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hippocrates
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PubMed_Summ_test

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id stringlengths 11 16	query stringlengths 279 826k	answer stringlengths 174 4.34k
PubmedSumm118800	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: despite a 2008 world health organization analysis which does not predict health workforce shortages in the developed world over the next decade , some developed countries still deal with health workforce shortages and specialty imbalances . different countries have begun to look to medical task - shifting as one way to address physician workforce shortages . since the 1960s , the united states ( us ) has deployed over 80,000 physician assistants ( pas ) . pas have been characterised as a new healthcare professional who , while not a doctor , works to the medical model , with the attitudes , skills and knowledge base to deliver holistic care and treatment under defined levels of supervision . . they have a semi - autonomous status and work under the supervision of a fully trained doctor . pas obtain medical history , perform physical examination , request additional testing ( from simple laboratory tests to advanced imaging investigations ) , render diagnoses , prescribe medication , assist in surgery , and perform a wide range of therapeutic services . numerous american studies suggest that quality of care provided by pas is comparable with physician care and that patients , healthcare administrators and doctors are all satisfied with the current implementation of pas . in the us , the anticipated shortage of physicians will most likely lead to a substantial increase in the number of practising physician assistants . the number of clinically active physician assistants is anticipated to increase by 72% to nearly 128,000 by 2025 . in contrast , only few european countries currently have adopted the physician assistant model to address health workforce concerns . employment of physician assistants and/or development of education programs are reported from germany , united kingdom and the netherlands . in order to characterize physician assistant practice and training in europe , a literature search was conducted . the literature search , while not being a systematic review , was performed using the academic search premier , cinahl , eric and medline databases . a search strategy was carried out using the terms physician assistant and germany , united kingdom and the netherlands . from this select group of articles it is set out to define the pa profession and the current state of the workforce in europe . therefore also the websites of the existing pa professional organizations and universities which train pas in europe were queried to gather current information on the numbers of practicing physician assistants , physician assistant students and pa training programs . currently , european physician assistants are trained and are practicing in three countries : germany , united kingdom and the netherlands . each of these three countries has a slightly different approach to training and deployment of physician assistants . this analysis excludes american physician assistants employed by the us government who practice on american military bases in europe and are regulated via the us government . there are currently no peer - reviewed systematic studies indexed in the above mentioned databases describing the practice of physician assistants in germany . however , query of german pa leaders reveals that there are three academic programs training physician assistants . all three programs educate registered nurses ( and other para - medical personnel ) after their three - year vocational training towards a b.sc . all three programs may be characterized as dual education programs ( academic training with integrated work experience in the profession ) and have a workload of 180 ects within three years . at the steinbeis - hochschule berlin ( shb ) , the program was expanded in 2009 to incorporate pa training as well as training for cardiology assistants and intensive care practitioners . a formal cooperation was initiated with the german society for orthopaedic and trauma surgeons in order to accommodate a certificate of competency in this field . a total of 41 physician assistants have been graduated at this institution , and 33 students are currently enrolled ( november 2011 ) . the mathias - hochschule in rheine ( mhr ) started its physician assistant program in 2011 . a total of 37 students have been admitted up to date ( november 2011 ) . as of the date of this publication , two of three programs ( shb and mhr ) received national accreditation ( akkreditierungsrat ) . legislation for pa practice was initiated in the federal state of baden - wrttemberg with the aim to protect the title arztassistent and to define the scope of practice . as of november 2011 , this initiative however has not yet proven successful . in germany , pas are reported to work in surgery ( cardiac , trauma , orthopedic , plastic ) , emergency departments , internal medicine , oncology and pediatrics . most of the articles identified in the literature search are simply descriptions of the experience of individual doctors or pas with the new profession in the uk . ritsema and paterson published the results of the first census of uk pas in october 2011 . the authors indicate that this census will be performed annually to track the development of the profession in the uk . drennan et al . published a qualitative study of the experience of general practice physicians who employ pas . in addition , formal evaluations of the english and scottish pa pilot projects , in which american pas were brought to the uk to test the feasibility of the pa role within the nhs , have been published . the united kingdom ( uk ) has been training physician assistants in limited numbers since 2005 . at the end of 2011 , george s university of london ( sgul ) and one at the university of aberdeen in scotland . thirty five students enrolled as first year students in the training programs at sgul or aberdeen in september 2011 . these programs award a post - graduate diploma in physician assistant studies and require an honours degree in biological or medical sciences prior to matriculation . physician assistant programs in the uk require a year of full - time classroom study , followed by a year of full time clinical placement experience in a variety of medical specialties , with a goal to train the pas for use as a generalist medical provider . as part of the process for developing the uk pa census , the united kingdom association of physician assistants , the uk and ireland universities board for pa education , and the existing pa programs were queried in december 2010 . these organizations identified 71 people who are qualified to practice as pas in the uk , and 94 individuals who were enrolled as students in a uk pa program . a census of uk pas performed in january 2011 reveals that both us and uk trained pas are practicing in a wide variety of specialties and settings . pas in the uk practice in at least 19 different specialities , with the more than 1/3 of pas serving in general practice . the remaining pas practice in both medical and surgical subspecialties , as well as in emergency medicine and psychiatry . pas are working in outpatient clinics , inpatient wards , emergency departments , intensive care units and psychiatric facilities . a recent change in the national government due to a parliamentary election has slowed progression of the application for professional registration . until pas are registered as a profession , they will be unable to prescribe medications , which may prove a limit to the expansion of the profession in the uk . other training programs are located in amsterdam ( in holland university of applied sciences ) , arnhem / nijmegen ( han university of applied sciences ) , groningen ( hanze university of applied sciences groningen ) and the rotterdam university . in 2010 , 135 students enrolled in one of the five dutch pa programs . the education model of the pa programs in the netherlands is unique in its kind and differs from the us model by being a competency - based , dual - approach curriculum . this curricular structure means that the pa students are also employed as pa trainees within a particular medical specialty starting from the day of their enrolment . so , next to their in - school generalist education , they also already gain specialty care competencies during their training . all programs are offered through universities of applied sciences and are fully accredited by the accreditation organisation of the netherlands and flanders ( nvao ) . the training program covers 30 months and accounts for 150 ects ( 4200 clock hours ) . dutch physician assistants have organized themselves by means of a professional association , the netherlands association of physician assistants ( napa ) . the napa has played an important role en route towards the legal recognition of the pa profession . recently , amendments to the act on professions in the individual health ( the so - called big law ) in order to enable medical task shifting , have been accepted by the first house of parliament . enactment of the changes in the big law - being an experiment article of the big law , under orders in council for a fixed term of five years after which it will be evaluated whether a full incorporation of the pa profession is justified - by publication in the law gazette , will allow the physician assistant to perform tasks that were previously reserved for medical doctors . in addition to establishing medical diagnoses , these tasks include the performance of surgical procedures , endoscopies , catheterizations , punctures , elective cardioversion , defibrillation and prescribing medications . this authorization covers acts that fall within the competence and training area of the pa , typically , routine procedures with a limited risk . these procedures may only be performed by pas if they adhere to current national guidelines , standards and protocols . medical practice by pas is only possible in a collaborative partnership with a medical doctor . from the napa website it is found that dutch physician assistants practice medicine in the specialties as displayed in box 1 . medical specialties of physician assistants in the netherlands these numbers do not reflect the up - to - date workforce . reasons include the fact that not all graduates are member of the napa , the survey was conducted in 2009 and also includes pa students . however , this data is indicative for the wide - range of medical specialties in which pas practice medicine . impact and quality indicators . the introduction of a new profession to medicine should be accompanied by studies on impact and quality of care . currently , only few studies have addressed this issue in europe . in a study from scotland , the scope of practice of physician assistants was evaluated . in primary care , intermediate care , emergency medicine , out of hours clinic and orthopaedics , the range of tasks varied from history taking , examination , formulation of a differential diagnosis to performing medical tasks without direct supervision . physician assistants performed tasks in the range from nurse practitioners to mid - level or generalist doctors . the authors found that the physician assistants worked safely , that their work was valued , that they added complementary skills to the team , but that a strong and trusting relationship with their supervising medical doctor was necessary . a 2005 study of the english pilot program of pas deployed in general practice and emergency medicine settings had similar findings . drennan , et al . performed a qualitative study of the general practice physicians who employ physician assistants in the united kingdom . the employers reported that physician assistants in general practice were able to conduct a high volume of work with low levels of supervision , although less experienced , but that new graduate pas were less efficient and required more supervision than those with more experience . also , patients accepted these professionals and sometimes even specifically asked to be treated by the physician assistant . the biggest limitation on the profession from the perspective of the employers was a lack of a regulatory framework for pa , together with a lack of prescribing authority . one study from the netherlands worked to characterize the role of the physician assistant and the degree to which pas can substitute for physician practice . this study also evaluated facilitators and barriers experienced in the reallocation of medical tasks . in that paper , it was noted that 45,2% of their working time was spent with direct patient care , and that medical activities was the largest portion ( 34,2% of total working time ) of this set of activities . however , one of the findings of that time of the study was that the lack of a legal framework was seen as prominent barrier . pas are slowly beginning to change the paradigm of medical practice in three european countries . regardless of the local definitions of the pa ( i.e. practicing medicine under supervision or in partnership with a medical doctor ) , the pa profession is beginning to establish itself as an important link to help guarantee access to and continuity of quality medical care . pas ought to be considered as a new type of medical professional , which has the potential to impact medical practice , once it is more widely deployed . despite differences in the model of training and deployment within europe , pas in these different health systems share a common denominator , namely performing medical tasks . while conducting this literature analysis it shows that the pa workforce , with approximately 500 graduates , in the netherlands takes a leading position regarding medical task shifting against the other european countries that employ pas . it is clear that pa training in the netherlands - although in terms of the educational model it differs from that of the united states - does satisfy the entry level of a master s degree as adopted in the united states . it should also be evident that the upcoming , though irreversible legalization of the profession in the netherlands , albeit through an experiment article in the professions act , brings about a major step forward in the recognition of this new medical professional and probably will serve as an example for pa workforces ( in development ) on the european continent . another remark which is justified to pose is the importance of the dual approach of training pas . to get enrolled to the professional master one of the admission criteria for starting the training as a pa , in as well the netherlands as in germany - which possibly has a number of advantages over a complete in - school training - is the minimum of two years clinical experience prior to enrollment . this , undeniably , brings the student into a situation in which they do not have to get used to working with patients . this allows a steeper , faster learning curve be made in expanding the already present basic medical knowledge and inherently increase the process of clinical reasoning . but it eventually also creates an additional advantage from the patient perspective , i.e. a trainee medical professional who is already able to approach the medical problem from a patient s standpoint of view . the assumption of expanding medical knowledge instead of learning everything from the start especially accounts for the situation in the netherlands , where students have already acquired a bachelor s degree in a health related science . during those previous 4 years students already got exposed to basic sciences and patient problems . besides these benefits it also has to be mentioned that training pas in a dual program prevents the negative impact of withdrawing pa students from their environment . most often , students namely remain working in their specialty , though in another role and new set of tasks , but not causing a drain based on the total staffing of a department . in order to overcome the effect of understaffing , in the netherlands the ministry of health also provides a salary compensation to the employer , so that they can fill in this gap , simply by hiring an alternate who continues to perform the previous work of the pa trainee . literature about the physician assistant from europe is scarce . rather a lot of information in this study is identified outside indexed journals , namely in policy documents , on websites of involved associations and based upon expert - opinion . to proof the potency of the pa profession for the european health market , further studies are needed in order to precisely measure the impact of the pa profession on medical healthcare in europe . such studies should endeavour to characterize the profession from the standpoint of the physician assistant , the doctors who employ pas , patients who are cared for by pas and health administrators of systems which use pas . Output:	introductionphysician assistants are medical care providers working under supervision and/or in collaboration with a medical doctor . the physician assistant profession has its origin in the united states , but in the last decade has also reached other nations to overcome medical staffing issues . with little summarized literature available , the aim of this study is to portray the physician assistant movement in europe.methodsa literature search was conducted in academic search premier , cinahl , eric and medline databases . in addition , european pa educational programs , professional associations , and local experts on the pa profession were queried.resultscurrently , in europe there are three countries in which physician assistants are trained and are working . the educational models of physician assistant training in the united kingdom , germany and the netherlands differ , as do the degrees offered by the training institutions.conclusionsthere is scant literature about physician assistant training and practice in europe available in the common scientific databases . the paucity of literature makes it difficult for an outsider to observe the developments and to value the impact of a new profession on national health systems . further high - quality research is needed to adequately characterize physician assistant education and implementation across europe .
PubmedSumm118801	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: osteoporosis is an important age - related disease constituting a major health problem especially among postmenopausal women . in women , the rate of bone loss increases dramatically after menopause or ovariectomy due to oestrogen deficiency . thus , there is an increased rate of activation of remodeling sites resulting in the decrease of both trabecular and cortical bones . in addition , oestrogen deficiency has been associated with oxidative stress because oestrogen is an antioxidant with radical - scavenging properties . the levels of lipid peroxidation ( lpo ) and hydrogen peroxide ( h2o2 ) were increased and enzymatic antioxidants like superoxide dismutase ( sod ) , glutathione peroxidase ( gpx ) , glutathione s transferase ( gst ) were decreased in the femur of ovariectomized rats . oxidative stress has been shown to stimulate osteoclast differentiation and function as well as inhibit osteoblast differentiation . glutathione peroxidase 1 ( gpx1 ) is the main antioxidant enzyme expressed in osteoclasts and is responsible for the degradation of hydrogen peroxide . hydrogen peroxide is essential for oestrogen deficiency bone loss and osteoclast formation , suggesting a crucial role for hydrogen peroxide in osteoclast formation . 17-estradiol stimulates gpx1 expression in bone - marrow - derived osteoclasts , and oestrogen deficiency was a key step in the reactive oxygen species ( ros- ) mediated stimulation of tnf expression , leading to enhanced osteoclastogenesis and bone resorption . plasma total oxidative status ( tos ) and oxidative stress index ( osi ) value were significantly higher , and plasma total antioxidant status ( tas ) level was lower in patients than in healthy controls ( p < 0.001 for all ) . there was a significant negative correlation between osi and bone mineral density ( bmd ) in lumbar and femoral neck region ( r = 0.63 , p < 0.001 ; r = 0.40 , p = 0.018 ) . these findings indicated that increased osteoclastic activity and decreased osteoblastic activity may be associated with an imbalance between oxidant and antioxidant status in postmenopausal osteoporosis . our own earlier studies showed that ferric nitrilotriacetate ( fe - nta ) , a strong oxidising agent , increased osteoclast number and reduced osteoblast number in rat femoral bone . trabecular thickness was also lower in the group treated with fe - nta , compared to the normal control . in light of these findings , it is hypothesized that antioxidants can prevent postmenopausal bone loss . each of them has four stereoisomers respectively , namely , - , - , - , and -tocopherols ( t ) and tocotrienols ( t3 ) . tocopherols contain a saturated phytol side chain in the chroman ring and a saturated hydrocarbon chain . on the other hand , palm tocotrienol at the dose of 100 mg / kg body weight significantly reduced the thiobarbituric acid reactive substances ( tbarss ) level in the femur with a significant increase in glutathione peroxidase activity compared to the age - matched control group . our earlier studies have shown that tocotrienol was able to prevent and even reverse osteoporosis in oestrogen deficiency , testosterone deficiency , glucocorticoid excess , and nicotine exposure [ 713 ] . the dose of tocotrienol , 60 mg / kg , had been established as the optimum dose for bone protection which we have established in our previous studies [ 5 , 1315 ] . the richest source of calcium includes cheeses and low - fat dairy products such as milk , yogurt , and tau - fu . calcium supplementation has been used as treatment for osteoporosis . in adults with a baseline calcium intake of 500900 mg / day , increasing or supplementing this intake by a further 5001000 mg / day has a beneficial effect on bone mineral density . quantitative changes in bone turnover can be assessed easily and noninvasively by the measurement of serum and urinary biochemical markers ; the most sensitive markers include serum osteocalcin , bone specific alkaline phosphatase , the n - terminal propeptide of type i collagen for bone formation , and the crosslinked c-(ctx ) and n-(ntx ) telopeptides of type i collagen for bone resorption . in this study we assayed serum osteocalcin and ctx . the serum cross - linked c - telopeptide of type i collagen ( ctx ) is a marker of osteoclast activity and is used to assess the level of bone resorption . it plays an important role in the regulation of bone growth and in the correct deposition of the minerals in the matrix . its expression follows the proliferative phase of osteoblastic differentiation , so it can be considered a marker of mature osteoblasts . bone histomorphometry is the quantitative study of the microscopic organization and structure of bone tissue by computer - assisted analysis of images formed by a microscope . bone histomorphometry contains three sets of parameters , namely , structural , static , and dynamic parameters . in this study we studied the dynamic bone histomorphometry which measures the rate of bone growth over time . the aim of this study was to compare between the effects of palm tocotrienols and calcium supplementation on bone metabolism ovariectomised ( oestrogen - deficient ) rats . the results of this study will indicate whether the tocotrienols are better than calcium as supplements to prevent osteoporosis in the postmenopausal state . thirty - two female sprague - dawley rats ( four months old ) weighing between 180 and 200 g were obtained from the laboratory animals resource unit , universiti kebangsaan malaysia . ovariectomised - control ( ovc ) , ovariectomised and given 60 mg kg of tocotrienol mixture ( ov+t ) , and ovariectomised and given 1% calcium in drinking water ad libitum ( ov+ca ) . two to three rats were kept in a cage under 12-hour natural light / dark cycles . all rats received normal rat chow from gold coin ( port klang , selangor , malaysia ) . calcium content of the rat chow as given by the supplier was between 0.8 1.2% . ( ipoh , malaysia ) consisting of -tocotrienol 24.67% , -tocotrienol 38.955% , -tocotrienol 4.55% , and -tocopherol 20.11% . it was diluted in olive oil ( bertolli , italy ) and given via oral gavage at the dose of 60 mg kg body weight daily at 9 am for 8 weeks . calcium supplementation was administered as 1% calcium in drinking water ad libitum . for measurement of dynamic histomorphometric parameters , the bone samples were double labelled by intraperitoneal injections of a fluorochrome , calcein , at 9 days and 2 days before sacrifice . the fluorochrome was incorporated into the active formation sites in the bone and can be visualised as fluorescent lines by fluorescent microscopy . a baseline control group ( bc ) of eight rats was given the calcein injections upon receipt and sacrificed without any treatment . blood samples were collected before the start and after eight weeks of treatment from the retroorbital vein after anesthetizing the rats with ether . after 3 hours in room temperature , the blood was centrifuged at 3000 rpm for 10 min and the serum was stored at 70c . bone biochemical markers of serum osteocalcin and c - terminal telopeptide of type 1 collagen ( ctx ) were measured before and after the treatment using an elisa reader ( versamax , sunnyvale , usa ) . the kits used were rat osteocalcin elisa ( biomedical technologies , herlev , denmark ) and ratlaps elisa ctx-1 ( nordic biosciences , ids , uk ) . the dynamic bone histomorphometric parameters were measured according to the american society of bone mineral research histomorphometry nomenclature committee 1987 . after one week , the femora were cut sagittally at the epiphyseal and metaphyseal area . the femora were then embedded in methyl methacrylate ( osteo - bed bone embedding kit ; polysciences , usa ) and sectioned at 9 m thickness using a microtome ( leica rm2155 , wetzlar , germany ) . the unstained bones were analyzed using an image analyzer pro - plus ( media cybernetics , silver spring , md , usa ) and a fluorescence microscope ( nikon eclipse 80 , japan ) . the dynamic bone histomorphometric parameters include single - labeled surface / bone surface ( sls / bs ) , double - labeled surface / bone surface ( dls / bs ) , mineralizing surface / bone surface ( ms / bs ) , bone formation rate / bone surface ( bfr / bs ) , and mineral apposition rate ( mar ) . the primary parameters are the single - labeled surface ( sls ) and double - labeled surface ( dls ) . the dls represented bone growth in seven days , while the sls was actually two calcein labels superimposed on each other due to insignificant bone growth . the sls / bs and dls / bs parameters are obtained using the weibel grid as described by freere and weibel . the other parameters were derived as follows : ms / bs = [ dls + 1/2 sls]/bs and bfr / bs = [ dls + 1/2 sls x mar]/bs . the mar was calculated by obtaining the mean interlabel distance using the pro plus image anaylzer and dividing it by seven days , which is the duration of time between the calcein injections . this secondary spongiosa area is located 3 to 7 mm from the lowest point of the growth plate and 1 mm from the lateral cortex , excluding the endocortical region . the kolmogorov - smirnoff tests were used for normality testing . following that the kruskal - wallis andmann - whitney u tests were used for comparison between treatment groups since the data were not normally distributed . to compare data between before and after treatment , the wilcoxon rank sign test was used . data analysis was carried out using the statistical package for social sciences ( spsss ) version 19.0 software . the results were expressed as mean values standard error of the mean ( sem ) . this study was approved by universiti kebangsaan malaysia animal ethics committee ( ukmaec ) certificate no : fp / far/2010/nazrun . sls indicates that there was poor bone growth , such that the two calcein labels were superimposed on each other . figure 1 showed that increased percentage of sls in the ovc group , while both calcium and tocotrienol significantly reduced the percentage of sls . ovariectomy did not significantly change the percentage of dls compared to bc and sham . however , tocotrienol significantly increased percentage of dls more than all the other groups ( figure 2 ) . calcium supplementation to the ovariectomised rats ( ov+ca ) did not increase the mar ( figure 4 ) . the ctx levels were significantly lower in all the groups after treatment . however , there were no significant differences before and after treatment for all the groups ( figure 6 ) . there were no significant differences in serum osteocalcin levels seen between groups as well as within groups ( figure 7 ) . during early adulthood , bone mass is stable until menopause . for about the first five years after menopause , women lose bone mass at the rate of about 2% to 3% per year and then continue to lose about 1% of bone mass per year to the end of life . early reports by others showed that calcium supplementation in postmenopausal women for two months was shown to be effective in preventing osteoporosis . however , no improvement in the dynamic histomorphometry was observed . the position statement on calcium and bone health by the australian and new zealand bone and mineral society , osteoporosis australia , and the endocrine society of australia states that the effect of calcium supplementation on bone health is modest , as shown by increases in bmd and reductions in excessive bone turnover . however , the relative risk reduction for osteoporotic fracture is likely to be no more than 10%20% . although inadequate calcium intake is likely to be deleterious to bone , calcium intake significantly above the recommended level is unlikely to achieve additional benefit for bone health . this is in agreement with our study which did not find any significant improvement in bone formation in rats supplemented with calcium . palm vitamin e contains a mixture of tocopherols and tocotrienols but with a higher percentage of tocotrienol . our previous animal studies found that both tocotrienols and tocopherols were able to prevent the decline in bone density due to various factors . however , the tocotrienols were found to have better efficacy in some studies [ 10 , 13 , 23 ] . in fact , tocotrienol was also shown to improve bone biomechanical strength better than -tocopherol . a study by fujita et al . found that -tocopherol actually increases bone resorption by stimulating osteoclast fusion , an effect that was not shown by -tocotrienol . this effect of -tocopherol was thought not to be due to its antioxidant properties , since other antioxidants , including -tocotrienol , simultaneously tested , did not show that effect . in this study , our preparation was mainly tocotrienol , and it showed significantly better effects on bone formation in oestrogen - deficient rats compared to calcium . therefore , we postulate that the beneficial effects were due to the tocotrienol component and not -tocopherol , since our previous studies showed that -tocopherol was less effective . furthermore , the study of fujita et al . indicated that -tocopherol was harmful to bone . thus , it is important to remove the -tocopherol component from palm vitamin e , leaving only the beneficial tocotrienols in place . in this study , however , no significant changes in the serum bone biomarkers were seen even though ctx was significantly lower in all the groups after treatment compared to before treatment was started . this may be because serum biomarkers are subject to circadian rhythm , therefore variation in serum levels may contribute to the insignificant results seen . another reason may be that bone remodeling is a dynamic process , thus serum biomarkers are in a constant state of fluctuation . furthermore , the technique may not be sensitive enough to detect small changes in nanograms per milliliter . the antiosteoporotic effects of tocotrienol are better illustrated in the dynamic histomorphometric parameters since findings in bone are more stable and lasting compared to serum findings . the rats in group ov+ca were treated with 1% calcium in drinking water , ad libitum daily for two months . one gram of calcium was powdered and mixed with 99 ml of deionised water which the rats drank when needed . in this way however , this method was selected since it did not cause any trauma to the animals . this is unavoidable since the tocotrienol and vehicle were administered by daily oral gavage . to administer calcium in this way will mean two oral gavages in a day which might traumatize the animal too much . we have successfully used this mode of administration of calcium in our earlier studies [ 14 , 26 , 27 ] . . mentioned that the benefits of calcium treatment are more consistent in late postmenopausal women than in perimenopausal women , perhaps because of greater variation in the rate of bone loss amongst perimenopausal women . in the present study , the menopausal state in rats this may contribute to the results seen in our study , which showed that calcium supplementation did not significantly affect bone resorption and formation . in conclusion , tocotrienols increased bone formation rate in oestrogen - deficient ovariectomised rats , while calcium did not . Output:	postmenopausal osteoporosis is the commonest cause of osteoporosis . it is associated with increased free radical activity induced by the oestrogen - deficient state . therefore , supplementation with palm - oil - derived tocotrienols , a potent antioxidant , should be able to prevent this bone loss . our earlier studies have shown that tocotrienol was able to prevent and even reverse osteoporosis due to various factors , including oestrogen deficiency . in this study we compared the effects of supplementation with palm tocotrienol mixture or calcium on bone biomarkers and bone formation rate in ovariectomised ( oestrogen - deficient ) female rats . our results showed that palm tocotrienols significantly increased bone formation in oestrogen - deficient rats , seen by increased double - labeled surface ( dls / bs ) , reduced single - labeled surface ( sls / bs ) , increased mineralizing surface ( ms / bs ) , increased mineral apposition rate ( mar ) , and an overall increase in bone formation rate ( bfr / bs ) . these effects were not seen in the group supplemented with calcium . however , no significant changes were seen in the serum levels of the bone biomarkers , osteocalcin , and cross - linked c - telopeptide of type i collagen , ctx . in conclusion , palm tocotrienol is more effective than calcium in preventing oestrogen - deficient bone loss . further studies are needed to determine the potential of tocotrienol as an antiosteoporotic agent .
PubmedSumm118802	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: adipose tissue is a major endocrine organ producing a variety of adipokines affecting energy balance . obesity is characterized by increases in the number ( hyperplasia ) and in the size ( hypertrophy ) of adipocytes through mitosis and differentiation , and through increased triglycerides ( tg ) storage in mature adipocytes . obesity is intimately associated with many metabolic diseases , such as lipid disorders , coronary heart diseases , hypertension , and diabetes mellitus . therefore , investigating safe , effective , and long - term ways to decrease body weight is an important issue in preventing a number of chronic diseases . aquaporin-7 ( aqp7 ) is expressed in adipose tissue , testis , kidney , and heart [ 47 ] , and is regulated through fasting / feeding , insulin , dexamethasone , glucocorticoids , cytokines , epinephrine , and peroxisome proliferator - activated receptor ( ppar)- agonists , including rosiglitazone , which activates adipogenesis and lipid accumulation in tissues , as well as increasing insulin sensitivity . aqp7 plays an important role in glycerol secretion from adipose tissue and facilitates glycerol transport , leading to a reduction in tg levels . apelin is a small peptide found in a number of tissues , including adipose tissue , and has emerged as a new factor with potent effects on energy metabolism and on the improvement of insulin sensitivity [ 1113 ] . previous studies reported that apelin was associated with obesity [ 1416 ] , but the mechanisms are still largely unknown . a study reported that long - term ( 2 weeks ) peripheral injection of apelin decreased the tg content in adipose tissue and the weight of different fat tissues in chow - fed mice and in obese mice . plasma tg levels were also decreased in normal and obese apelin - treated mice . among insulin - responsive tissues , the apelin receptor is expressed in adipose tissue , skeletal muscles , and the liver . however , upstream signal regulatory factors leading to apelin - induced effects are still not completely elucidated . a previous study showed that apelin-13 increased vascular smooth muscle cell proliferation through the pi3k pathway , but the involvement of pi3k in adipocyte metabolism is unknown . we selected apelin-13 because it was previously investigated in obese mice and was shown to influence adiposity in these mice , as well as being one of the most active isoforms . we hypothesized that apelin decreases lipid storage , at least in part , through an autocrine pathway involving aqp7 . therefore , the purpose of this study was to assess the effects of apelin-13 on decreased lipid storage and on aqp7 expression in hypertrophic adipocytes , and the involvement of the pi3k signaling pathway . the 3t3-l1 pre - adipocytes were purchased from the cell bank of the type culture collection of the chinese academy of sciences ( shanghai , china ) . carlsbad , ca , usa ) supplemented with 10% calf serum ( gibco , invitrogen inc . , carlsbad , ca , usa ) with 5% co2 at 37c . upon reaching 100% confluence , cells were incubated with dmem supplemented with 10% calf serum for 2 days and then transferred into a differentiation - induction medium containing methylisobutylxanthine ( 0.5 mm ) , dexamethasone ( 1 m ) ( sigma , st louis , mi , usa ) , and insulin ( 5 mg / l ) ( sigma ) in dmem containing 10% fetal bovine serum ( fbs ) ( hyclone , south logan , ut , usa ) . after 2 days ( at day 4 ) , the differentiation - induction medium was replaced with dmem containing only insulin ( 5 mg / l ) for another 2 days . cells were then cultured in dmem without insulin . on days 810 , more than 90% of cells displayed an adipocyte phenotype with the accumulation of lipid droplets . differentiated adipocytes were cultured for 12 h in serum - free dmem to synchronize them ; they were then cultured in dmem containing 10% fbs and 0.1 mm palmitate ( sigma ) for 48 h. hypertrophic 3t3-l1 cells were treated with 0 , 1 , 10 , 100 , and 1000 nm of apelin-13 ( phoenix biotech , phoenix , usa ) for 0 , 12 , 24 , 36 , and 48 h. cells were cultured with 10 m rosiglitazone ( taiji group , chongqing , china ) as the positive control . to determine the involvement of pi3k in apelin - stimulated aqp7 expression , ly294002 10 m ( sigma ) was preincubated 30 min before the incubation of hypertrophic 3t3-l1 cells with 100 nm of apelin-13 . after differentiation or hypertrophy , cells were washed 3 times with phosphate - buffered saline ( pbs ) , fixed with 4% paraformaldehyde for 30 min at room temperature , and stained with filtered oil red o solution ( 60% isopropanol and 40% water ) for 1 h at 37c . after staining , oil red o was removed and the plates were rinsed with water and dried . images were obtained using a microscope ( eclipse te2000-s , nikon instruments , tokyo , japan ) . cells were treated with palmitate at concentrations of 0 , 0.1 , 0.2 , and 0.4 mm for 48 h in 6-well plates after adipocyte differentiation for 8 days . hypertrophic 3t3-l1 adipocytes were cultured for 48 h with apelin-13 100 nm , with or without a 30-min preincubation with ly294002 10 m . cells were washed with pbs twice to remove glycerin , and were treated with 200 l of lysis buffer on ice . lysates ( 50 l ) were heated at 70c for 10 min , and centrifuged at 2000 rpm for 5 min at room temperature ; cellular tg content in supernatant was then assessed with the triglyzyme - v commercial tg assay kit ( applygen technologies , beijing , china ) . the remaining lysates were used to quantify protein concentration using a bca protein assay kit ( pierce chemical , dallas , tx , usa ) . the ratio of the absorbance at 260 nm and 280 nm ( a260/a280 ) was used to assess rna purity . reverse transcription was performed with 0.2 g of total rna using the high - capacity cdna reverse transcription kit ( beijing transgen biotech co. ltd . , pcr was performed using a mycycler thermal cycler pcr system ( bio - rad , hercules , ca , usa ) using : aqp7 : forward 5-gaa cag tga gaa aaa gac cg-3 and reverse 5-cca gac aat cca gag ttc at-3 ; 18s ribosomal rna ( 18s rrna ) : forward 5-ttg gtg gag cga ttt gtc tg-3 and reverse 5-aat ggg gtt caa cgg gtt ac-3 ) . all reactions involved initial denaturation at 95 c for 5 min followed by 36 cycles of 95c for 30 s , 54c for 30 s , and 72c for 30 s. pcr products were separated by 2% agarose gel electrophoresis , stained with ethidium bromide , and analyzed using the alpha innotech software ( bio - rad ) . a kinetic study was performed using different numbers of cycles in order to determine the optimal number of cycles for mrna quantification during the exponential phase . aqp7 expression was normalized to the 18s rrna expression level , and was quantified using a standard curve . there was no significant difference in baseline 18s rrna levels between control and apelin-13- or palmitate - treated adipocytes . cells were treated with the ripa lysis buffer ( biocolor bioscience & technology co. , ltd . , shanghai , china ) on ice for 10 min , and centrifuged at 4 c , 12000 g for 15 min . cell lysates ( 40 g ) were separated by 12% sds polyacrylamide gel electrophoresis , and then transferred on polyvinylidene difluoride ( pvdf ) membranes ( 0.45 m ; millipore corp . , membranes were blocked with 5% skimmed milk in tris - buffer ( tbs ) with 0.1% tween 20 ( tbst ) , for 2 h at room temperature . membranes were blotted with rabbit polyclonal antibody against aqp7 ( 1:500 dilution , abcam , cambridge , ma , usa ) and mouse monoclonal antibody against -actin ( 1:1000 , boster bioengineering co. , ltd . , after being washed 4 times ( 10 min each ) in tbst buffer at room temperature , membranes were incubated with horseradish peroxidase ( hrp)-conjugated goat anti - mouse igg and hrp - conjugated goat anti - rabbit igg ( boster bioengineering co. , ltd . ) for 1.5 h. immunoreactive proteins were detected using a chemiluminescence ecl assay kit ( ge healthcare , little chanfont , uk ) according to the manufacturer s instructions . bands were visualized using a universal hood ii 76s/0608 image analyzer ( bio - rad , hercules , ca , usa ) . grayscale value of each band in imaging data was analyzed using quantity one software ( bio - rad , hercules , ca , usa ) . all measurements were performed in triplicates during 3 or 4 independent experiments . because results from each triplicate was averaged and because the average of the 34 experiments was used for analysis , data are expressed as means sem . anova and the least - square difference ( lsd ) tests were used for multiple comparisons . the 3t3-l1 pre - adipocytes were purchased from the cell bank of the type culture collection of the chinese academy of sciences ( shanghai , china ) . carlsbad , ca , usa ) supplemented with 10% calf serum ( gibco , invitrogen inc . , carlsbad , ca , usa ) with 5% co2 at 37c . upon reaching 100% confluence , cells were incubated with dmem supplemented with 10% calf serum for 2 days and then transferred into a differentiation - induction medium containing methylisobutylxanthine ( 0.5 mm ) , dexamethasone ( 1 m ) ( sigma , st louis , mi , usa ) , and insulin ( 5 mg / l ) ( sigma ) in dmem containing 10% fetal bovine serum ( fbs ) ( hyclone , south logan , ut , usa ) . after 2 days ( at day 4 ) , the differentiation - induction medium was replaced with dmem containing only insulin ( 5 mg / l ) for another 2 days . cells were then cultured in dmem without insulin . on days 810 , more than 90% of cells displayed an adipocyte phenotype with the accumulation of lipid droplets . differentiated adipocytes were cultured for 12 h in serum - free dmem to synchronize them ; they were then cultured in dmem containing 10% fbs and 0.1 mm palmitate ( sigma ) for 48 h. hypertrophic 3t3-l1 cells were treated with 0 , 1 , 10 , 100 , and 1000 nm of apelin-13 ( phoenix biotech , phoenix , usa ) for 0 , 12 , 24 , 36 , and 48 h. cells were cultured with 10 m rosiglitazone ( taiji group , chongqing , china ) as the positive control . to determine the involvement of pi3k in apelin - stimulated aqp7 expression , ly294002 10 m ( sigma ) was preincubated 30 min before the incubation of hypertrophic 3t3-l1 cells with 100 nm of apelin-13 . after differentiation or hypertrophy , adipocytes were stained with oil red o to detect lipid droplets . cells were washed 3 times with phosphate - buffered saline ( pbs ) , fixed with 4% paraformaldehyde for 30 min at room temperature , and stained with filtered oil red o solution ( 60% isopropanol and 40% water ) for 1 h at 37c . after staining , oil red o was removed and the plates were rinsed with water and dried . images were obtained using a microscope ( eclipse te2000-s , nikon instruments , tokyo , japan ) . cells were treated with palmitate at concentrations of 0 , 0.1 , 0.2 , and 0.4 mm for 48 h in 6-well plates after adipocyte differentiation for 8 days . hypertrophic 3t3-l1 adipocytes were cultured for 48 h with apelin-13 100 nm , with or without a 30-min preincubation with ly294002 10 m . cells were washed with pbs twice to remove glycerin , and were treated with 200 l of lysis buffer on ice . lysates ( 50 l ) were heated at 70c for 10 min , and centrifuged at 2000 rpm for 5 min at room temperature ; cellular tg content in supernatant was then assessed with the triglyzyme - v commercial tg assay kit ( applygen technologies , beijing , china ) . the remaining lysates were used to quantify protein concentration using a bca protein assay kit ( pierce chemical , dallas , tx , usa ) . total cellular rna was extracted using trizol ( invitrogen ) . the ratio of the absorbance at 260 nm and 280 nm ( a260/a280 ) was used to assess rna purity . reverse transcription was performed with 0.2 g of total rna using the high - capacity cdna reverse transcription kit ( beijing transgen biotech co. ltd . , pcr was performed using a mycycler thermal cycler pcr system ( bio - rad , hercules , ca , usa ) using : aqp7 : forward 5-gaa cag tga gaa aaa gac cg-3 and reverse 5-cca gac aat cca gag ttc at-3 ; 18s ribosomal rna ( 18s rrna ) : forward 5-ttg gtg gag cga ttt gtc tg-3 and reverse 5-aat ggg gtt caa cgg gtt ac-3 ) . all reactions involved initial denaturation at 95 c for 5 min followed by 36 cycles of 95c for 30 s , 54c for 30 s , and 72c for 30 s. pcr products were separated by 2% agarose gel electrophoresis , stained with ethidium bromide , and analyzed using the alpha innotech software ( bio - rad ) . a kinetic study was performed using different numbers of cycles in order to determine the optimal number of cycles for mrna quantification during the exponential phase . aqp7 expression was normalized to the 18s rrna expression level , and was quantified using a standard curve . there was no significant difference in baseline 18s rrna levels between control and apelin-13- or palmitate - treated adipocytes . cells were treated with the ripa lysis buffer ( biocolor bioscience & technology co. , ltd . , shanghai , china ) on ice for 10 min , and centrifuged at 4 c , 12000 g for 15 min . cell lysates ( 40 g ) were separated by 12% sds polyacrylamide gel electrophoresis , and then transferred on polyvinylidene difluoride ( pvdf ) membranes ( 0.45 m ; millipore corp . , billerica , ma , usa ) at 4c . membranes were blocked with 5% skimmed milk in tris - buffer ( tbs ) with 0.1% tween 20 ( tbst ) , for 2 h at room temperature . membranes were blotted with rabbit polyclonal antibody against aqp7 ( 1:500 dilution , abcam , cambridge , ma , usa ) and mouse monoclonal antibody against -actin ( 1:1000 , boster bioengineering co. , ltd . , after being washed 4 times ( 10 min each ) in tbst buffer at room temperature , membranes were incubated with horseradish peroxidase ( hrp)-conjugated goat anti - mouse igg and hrp - conjugated goat anti - rabbit igg ( boster bioengineering co. , ltd . ) for 1.5 h. immunoreactive proteins were detected using a chemiluminescence ecl assay kit ( ge healthcare , little chanfont , uk ) according to the manufacturer s instructions . bands were visualized using a universal hood ii 76s/0608 image analyzer ( bio - rad , hercules , ca , usa ) . grayscale value of each band in imaging data was analyzed using quantity one software ( bio - rad , hercules , ca , usa ) . all measurements were performed in triplicates during 3 or 4 independent experiments . because results from each triplicate was averaged and because the average of the 34 experiments was used for analysis , data are expressed as means sem . anova and the least - square difference ( lsd ) tests were used for multiple comparisons . the hypertrophic 3t3-l1 adipocytes created by incubation with 0.1 mm palmitate for 48 h were identified by oil red o staining ( figure 1c and 1d ) and they had a different appearance from fully differentiated 3t3-l1 adipocytes not exposed to palmitate , as shown by oil red o staining ( figure 1a and 1b ) . after oil red o staining , compared with differentiated 3t3-l1 adipocytes not exposed to palmitate , hypertrophic adipocytes were qualitatively characterized by : 1 ) an increased cellular volume ; 2 ) lipid droplets increased in number and in size ; and 3 ) decreased cellular adhesion ( figure 1c and 1d ) . levels of cytoplasmic tg adjusted for total cytoplasmic protein levels were different in adipocytes treated with palmitate . the 3t3-l1 differentiated adipocytes treated with 0.1 mm palmitate for 48 h accumulated significantly more cytoplasmic tg compared with control cells ( 0.1 mm : 6.930.80 m per g / ml vs. control : 5.040.33 m per g / ml , p<0.05 ) . there were no statistically significant differences among adipocytes treated with 0.2 mm and 0.4 mm of palmitate and control cells ( all p>0.05 ) ( figure 1e ) . palmitate induced an in vitro model of hypertrophic adipocytes with decreased aqp7 mrna expression compared with control cells ( 0.260.04 vs. 0.460.07 , p<0.05 ) ( figure 1f ) . there was a significant difference compared with controls ( no apelin-13 or 0 h ) when hypertrophic adipocytes were treated with 100 nm and 1000 nm of apelin-13 ( 100 nm : 0.540.06 and 1000 nm : 0.580.09 vs. control : 0.330.04 , both p<0.05 ) ( figure 2a ) or with 100 nm of apelin-13 for 12 , 24 and 36 h ( figure 2b ) . as shown in figure 2a , upregulation of aqp7 mrna expression by apelin-13 1000 nm was similar to upregulation by rosiglitazone 10 m ( positive control ) ( apelin-13 1000 mm : 0.580.09 vs. rosiglitazone 10 m : 0.610.09 , p>0.05 ) . aqp7 protein levels followed a similar trend with mrna expression when hypertrophic adipocytes were treated with 100 nm and 1000 nm of apelin-13 ( figure 2c ) or with 100 nm of apelin-13 for 24 and 36 h ( figure 2d ) . apelin-13 upregulated aqp7 protein levels ( apelin-13 : 0.540.06 vs. control : 0.280.06 , p<0.05 ) ( figure 3a ) while decreasing tg accumulation in hypertrophic adipocytes ( apelin-13 : 3.320.08 m per g / ml vs. control : 3.820.13 m per g / ml , p<0.05 ) ( figure 3b ) . the pi3k signaling pathway has been reported to play an important role in the apelin - mediated regulation of energy metabolism . in the present study , pretreatment using ly294002 10 m for 30 min prevented the increase in aqp7 expression observed when using apelin-13 alone ( apelin-13+ly294002 : 0.380.03 vs. apelin-13 : 0.540.06 , p<0.05 ) ( figure 3a ) , as well as the decreased cytoplasmic tg accumulation ( apelin-13 + ly294002 : 3.790.04 m per g / ml vs. apelin-13 : 3.320.08 m per g / ml , p<0.05 ) ( figure 3b ) . the hypertrophic 3t3-l1 adipocytes created by incubation with 0.1 mm palmitate for 48 h were identified by oil red o staining ( figure 1c and 1d ) and they had a different appearance from fully differentiated 3t3-l1 adipocytes not exposed to palmitate , as shown by oil red o staining ( figure 1a and 1b ) . after oil red o staining , compared with differentiated 3t3-l1 adipocytes not exposed to palmitate , hypertrophic adipocytes were qualitatively characterized by : 1 ) an increased cellular volume ; 2 ) lipid droplets increased in number and in size ; and 3 ) decreased cellular adhesion ( figure 1c and 1d ) . levels of cytoplasmic tg adjusted for total cytoplasmic protein levels were different in adipocytes treated with palmitate . the 3t3-l1 differentiated adipocytes treated with 0.1 mm palmitate for 48 h accumulated significantly more cytoplasmic tg compared with control cells ( 0.1 mm : 6.930.80 m per g / ml vs. control : 5.040.33 m per g / ml , p<0.05 ) . there were no statistically significant differences among adipocytes treated with 0.2 mm and 0.4 mm of palmitate and control cells ( all p>0.05 ) ( figure 1e ) . palmitate induced an in vitro model of hypertrophic adipocytes with decreased aqp7 mrna expression compared with control cells ( 0.260.04 vs. 0.460.07 , p<0.05 ) ( figure 1f ) . there was a significant difference compared with controls ( no apelin-13 or 0 h ) when hypertrophic adipocytes were treated with 100 nm and 1000 nm of apelin-13 ( 100 nm : 0.540.06 and 1000 nm : 0.580.09 vs. control : 0.330.04 , both p<0.05 ) ( figure 2a ) or with 100 nm of apelin-13 for 12 , 24 and 36 h ( figure 2b ) . as shown in figure 2a , upregulation of aqp7 mrna expression by apelin-13 1000 nm was similar to upregulation by rosiglitazone 10 m ( positive control ) ( apelin-13 1000 mm : 0.580.09 vs. rosiglitazone 10 m : 0.610.09 , p>0.05 ) . aqp7 protein levels followed a similar trend with mrna expression when hypertrophic adipocytes were treated with 100 nm and 1000 nm of apelin-13 ( figure 2c ) or with 100 nm of apelin-13 for 24 and 36 h ( figure 2d ) . apelin-13 upregulated aqp7 protein levels ( apelin-13 : 0.540.06 vs. control : 0.280.06 , p<0.05 ) ( figure 3a ) while decreasing tg accumulation in hypertrophic adipocytes ( apelin-13 : 3.320.08 m per g / ml vs. control : 3.820.13 m per g / ml , p<0.05 ) ( figure 3b ) . the pi3k signaling pathway has been reported to play an important role in the apelin - mediated regulation of energy metabolism . in the present study , pretreatment using ly294002 10 m for 30 min prevented the increase in aqp7 expression observed when using apelin-13 alone ( apelin-13+ly294002 : 0.380.03 vs. apelin-13 : 0.540.06 , p<0.05 ) ( figure 3a ) , as well as the decreased cytoplasmic tg accumulation ( apelin-13 + ly294002 : 3.790.04 m per g / ml vs. apelin-13 : 3.320.08 m per g / ml , p<0.05 ) ( figure 3b ) . in the present study , using 0.1 mm of palmitate , we implemented a model of hypertrophic adipocytes characterized by lipid droplets accumulation in the cytoplasm ; higher palmitate concentrations did not induce adipocyte hypertrophy , possibly due to intracellular palmitate cytotoxicity . these results suggest that apelin-13 decreases lipid storage through upregulating aqp7 expression in hypertrophic adipocytes by the pi3k signaling pathway . adipocyte differentiation and growth is highly controlled , and a number of crucial genes are involved . a number of studies showed that aqp7 , as no other aquaporin in adipose tissue , has been linked to regulation of fat tissue metabolism during periods of feast and famine , and that it is regulated by known regulators of fatty acids metabolism , such as insulin , dexamethasone , and epinephrine . aqp7 is barely expressed in pre - adipocytes , while it is markedly expressed in mature adipocytes . aqp7 facilitates glycerol transport from the cells , leading to the decrease of cytoplasmic tg levels through a decreased tg synthesis due to a lack of substrate . an aqp7-knockout mice model showed that increased adipose glycerol kinase activity accelerates tg synthesis in adipocytes , finally inducing obesity . indeed , aqp7 expression in adipose tissue is different in lean individuals compared with obese patients and the delicate balance in aqp7 expression is perturbed in obese subjects . moreover , some patients with a mutated or parafunctional aqp7 gene are at increased risk of developing obesity and/or type 2 diabetes . a downregulated aqp7 expression could then be involved in obesity susceptibility by reducing glycerol release and by promoting the accumulation of lipids in subcutaneous adipose tissue . studies also suggested that aqp7 expression is higher in visceral adipose tissue from obese subjects , compared with subcutaneous , in agreement with the fact that visceral adipose tissue is more metabolically active ( higher lipolytic capability ) than subcutaneous ( higher fat accumulation ) . therefore , in the present study , palmitate - induced tg accumulation in adipocytes may be associated with a decreased aqp7 expression . designing new modulators of aqp7 expression might be a way to treat obesity and its related complications . adipose tissue is a major endocrine organ , producing a variety of adipokines affecting energy balance . previous studies reported that apelin secreted by adipocytes contributes to decreased adiposity and to improved insulin resistance , but the mechanisms are still unknown . in the present study the present study showed that the levels of aqp7 mrna were not significantly different in adipocytes treated with 1000 nm of apelin-13 or 10 m of rosiglitazone . since aqp7 is known to increase glycerol transport out of the adipocytes , leading to a reduction in tg synthesis , we hypothesize that apelin downregulated tg accumulation in adipocytes by upregulating aqp7 expression . however , the effects of apelin-13 on the expression levels of key lipolytic enzymes still need to be assessed . nevertheless , since apelin is effective in inducing aqp7 expression in hypertrophic adipocytes , its use might be beneficial in treating obesity , as previously shown in mice . the effects of apelin-13 on aqp7 expression vanished after 48 h , which may be associated with apelin-13 degradation . a major finding of our study is that the pi3k pathway is involved in aqp7 upregulation by apelin-13 in adipocytes . apelin and its receptor are expressed in many tissues , and previous studies observed that the pi3k / akt pathway is downstream of the apelin receptor . the present study showed that ly294002 , a pi3k inhibitor , prevented the effects of apelin-13 in apelin - treated hypertrophic adipocytes . these results suggest that aqp7 is a new factor involved in apelin - mediated decreased lipid storage and attenuated insulin resistance , and that the pi3k pathway is involved . our results are in agreement with a previous study suggesting that insulin and leptin modulate aqp7 expression through the pi3k pathway : inhibiting the pi3k also decreased the effects of insulin and leptin on aqp7 expression . a study also showed that apelin-13 is involved in vascular smooth muscle cell proliferation through the pi3k pathway , suggesting that apelin-13 might also be involved in the proliferation of other cell types , such as in the hyperplasia observed in obesity . however , other transduction signal pathways ( such as erk , p38 mapk , and protein c kinase ) may be involved , and future research should also assess their effects on aqp7 expression in adipocytes and their role in lipid accumulation [ 4044 ] . in conclusion , our results suggest that apelin-13 decreases lipid storage in hypertrophic adipocytes through an aqp7 upregulation , and that the pi3k signaling pathway is involved in these effects , suggesting potential therapeutic targets against obesity and related health problems . Output:	backgroundadipocyte - secreted apelin contributes to decreased adiposity and to improved insulin resistance , but the mechanisms remain unknown . the present study aimed to assess if apelin-13 is an upstream signal regulation factor of aquaporin 7 ( aqp7 ) , a water - glycerol transporter present in the plasma membrane of adipocytes that plays a key role in the regulation of lipid accumulation.material/methods3t3-l1 pre - adipocytes were induced to fully differentiated adipocytes ; hypertrophic adipocytes were then induced using palmitate . the effects of apelin-13 on aqp7 expression in hypertrophic adipocytes were investigated before and after treatment with ly249002 , a pi3k inhibitor . accumulation of cytoplasmic triglycerides ( tg ) in hypertrophic adipocytes was also determined.resultswe found that 0.1 mm of palmitate induced a model of hypertrophic adipocytes with a lower aqp7 expression ( 0.260.07 vs. 0.460.04 , p<0.05 ) . apelin-13 100 nm or 1000 nm upregulated aqp7 mrna expression ( 100 nm : 0.540.06 and 1000 nm : 0.580.09 vs. control : 0.330.04 , both p<0.05 ) , and decreased accumulation of cytoplasmic triglycerides in hypertrophic adipocytes . pretreatment using 10 m ly294002 prevented the increase in aqp7 expression observed when using apelin-13 alone ( apelin-13 + ly49002 : 0.380.03 vs. apelin-13 : 0.540.06 , p<0.05 ) , as well as the decreased cytoplasmic tg accumulation ( apelin-13 + ly294002 : 3.790.04 m per g / ml vs. apelin-13 : 3.320.08 m per g / ml , p<0.05).conclusionsapelin-13 decreases lipid storage in hypertrophic adipocytes in vitro , possibly through the upregulation of aqp7 expression by the pi3k signaling pathway . treatment using apelin-13 and aqp modulators might represent novel treatment strategies against obesity and its related complications .
PubmedSumm118803	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: acute pancreatitis is one of the most common medical conditions encountered by medical professionals worldwide . while most cases resolve without sequelae , between 10 % and 20 % of patients will develop more serious adverse events such as pancreatic necrosis , with an increased rate of morbidity and mortality 1 . furthermore , approximately 30 % of patients with necrotizing pancreatitis will develop a secondary infection in the weeks following , usually 3 to 4 weeks after the onset of necrosis 2 . if left untreated , infected pancreatic necrosis has a markedly elevated mortality rate ; however , aggressive supportive care and intervention significantly improves outcomes 3 4 . ideally , therapeutic intervention is delayed to allow maturation of the collection to form walled - off pancreatic necrosis ( wopn ) . historically , surgical necrosectomy was performed ; however with adverse event rates of 40 % to 70 % and mortality rates as high as 56 % reported , this procedure possess its own toxicity and is typically approached with trepidation 5 6 . the panter study demonstrated that a step - up approach , starting with ct - guided percutaneous drain placement was superior to up - front open surgical necrosectomy , thus demonstrating the value of a minimally invasive approach for this condition 7 . direct transgastric endoscopic necrosectomy involving endoscopic ultrasound ( eus)-guided , translumenal drainage and debridement has been shown to be an effective treatment for wopn with an improved safety profile 8 9 10 . however , this approach can be complex and is limited to necrosis abutting the stomach or duodenum . direct percutaneous endoscopic necrosectomy was first described in 2000 as a novel minimally invasive intervention for debridement and washout of wopn with two series more recently reported in china and india ( table 1 ) as well as several case reports 11 12 13 14 15 16 . this novel interventional endoscopy approach utilizes a percutaneous access tract previously placed by interventional radiology methods to directly access the abscess or necrosis for debridement and washout using flexible endoscopy . furthermore , direct percutaneous endoscopic necrosectomy could possibly be used for various types of intra - abdominal fluid collections , regardless of anatomic location , provided that it can be first accessed by interventional radiology techniques . a recent clinical series from india illustrated the efficacy and safety of direct percutaneous endoscopic necrosectomy in the treatment of infected wopn 12 . in this study , we intend to confirm these results in a us referral center and further evaluate the clinical value of direct percutaneous endoscopic necrosectomy in the treatment of other types of intra - abdominal fluid collections and necrosis . in this retrospective cohort study , 12 consecutive patients undergoing direct percutaneous endoscopic necrosectomy over the period of 2007 to 2014 were identified . all patients had previously undergone ct - guided percutaneous drain placement without resolution of their symptoms due to the presence of solid necrosis and/or loculations . time to intervention was defined as the number of days between the onset of symptoms and the first percutaneous endoscopic necrosectomy . the primary endpoint was complete removal of all percutaneous drains without recurrence of clinical symptoms . time to resolution was defined as the number of days between the first endoscopic intervention and the date in which all drains were removed . prior to endoscopy , all patients had their percutaneous drains upsized to 24- to 28-f diameter to accommodate the endoscope through the body wall access point ( fig.1 a ) . once accessed , a fluid sample was collected and sent for amylase level and cytology . the patients were then placed under either moderate sedation with fentanyl and midazolam or general anesthesia if clinically warranted . the percutaneous drain(s ) was then removed and standard 8.8-mm upper endoscope ( gif - q180 ; olympus inc . , center valley , pa ) was introduced through the established tract into the necrotic cavity ( fig.1 b and fig.1 c ) . 1 d ) , lavaged with normal saline , and necrotic debris then removed using blunt removal and washout . a standard polypectomy snare was typically used through the scope to mobilize and remove solid debris ( fig . large necrotic pieces were sequentially removed over the course of the procedure , and once debridement was satisfactory , the endoscope removed and the percutaneous drain replaced over a guidewire . if needed , repeat percutaneous debridement would occur within a few days until all necrotic material was removed ( fig . 1 f ) . drain output was monitored and drains were downsized and then removed once output fell below 30 ml per day and cross - sectional imaging confirmed resolution ( fig.1 g ) . patients were subsequently followed in clinic over the course of 1 year to monitor for recurrence of signs or symptoms and need for further intervention . c fluoroscopy of percutaneous endoscope accessing wopn via sinus tract d initial visualization of necrotic cavity prior to debridement . g follow - up axial ct scan 9 months after direct percutaneous endoscopic necrosectomy demonstrating complete resolution of wopn . prior to endoscopy , all patients had their percutaneous drains upsized to 24- to 28-f diameter to accommodate the endoscope through the body wall access point ( fig.1 a ) . once accessed , a fluid sample was collected and sent for amylase level and cytology . the patients were then placed under either moderate sedation with fentanyl and midazolam or general anesthesia if clinically warranted . the percutaneous drain(s ) was then removed and standard 8.8-mm upper endoscope ( gif - q180 ; olympus inc . , center valley , pa ) was introduced through the established tract into the necrotic cavity ( fig.1 b and fig.1 c ) . 1 d ) , lavaged with normal saline , and necrotic debris then removed using blunt removal and washout . a standard polypectomy snare was typically used through the scope to mobilize and remove solid debris ( fig . large necrotic pieces were sequentially removed over the course of the procedure , and once debridement was satisfactory , the endoscope removed and the percutaneous drain replaced over a guidewire . if needed , repeat percutaneous debridement would occur within a few days until all necrotic material was removed ( fig . 1 f ) . drain output was monitored and drains were downsized and then removed once output fell below 30 ml per day and cross - sectional imaging confirmed resolution ( fig.1 g ) . patients were subsequently followed in clinic over the course of 1 year to monitor for recurrence of signs or symptoms and need for further intervention . b endoscopic image of sinus tract . c fluoroscopy of percutaneous endoscope accessing wopn via sinus tract d initial visualization of necrotic cavity prior to debridement . g follow - up axial ct scan 9 months after direct percutaneous endoscopic necrosectomy demonstrating complete resolution of wopn . a total of 12 patients underwent direct percutaneous endoscopic necrosectomy over the study time period ( table 2 ) . the majority of patients ( 75 % ) were female with an average age of 51 . ten patients ( 83 % ) had been diagnosed with wopn , one ( 8 % ) with omental necrosis after resection of a gastrointestinal stromal tumor , and one ( 8 % ) with bilateral , necrotic , loculated hepatic abscesses . six patients ( 50 % ) presented with manifestations of marked disease severity including sepsis and multiorgan failure . the median time from onset of symptoms until the first necrosectomy was 85 days ( range 21 248 ) ( table 3 ) . pen , percutaneous endoscopic necrosectomy complete removal of percutaneous drains was accomplished in 11 patients ( 92 % ) . the one patient in whom the drains were not removed died 3 months after her last pancreatic endocrine neoplasm ( pen ) from metastatic colon cancer . the median time from the initial pen to complete removal of drains was 57 days . one patient ( 8 % ) experienced a persistent sinus tract fistula , which has been treated conservatively . ten patients ( 83 % ) completed 1 year of outpatient follow up , none of whom required further intervention . one patient has had drains removed for 7 months ( at the time of publication ) and has not yet completed 1-year follow up . one patient died of metastatic colon cancer 3 months after her last necrosectomy with drains in place . previous studies have shown that a more minimally invasive , step - up approach with percutaneous drainage is superior to up - front surgery ; however , these patients often fail drainage and ultimately require surgical necrosectomy which carries high morbidity and mortality rates 3 7 . more recently , several endoscopic modalities have been developed to improve or replace the step - up approach and avoid surgical necrosectomy 3 8 9 . direct percutaneous endoscopic necrosectomy has shown initial promise in this arena , however , the supporting data are limited 11 12 . in this study , we have demonstrated the effectiveness and safety of direct percutaneous endoscopic necrosectomy in the treatment of infected wopn as well as other intra - abdominal fluid collections . when compared with the recent indian study by dhingra et al , the current series demonstrates a lower mean number of necrosectomy procedures required per patient ( 2.3 vs. 5 ) . we also had a longer median time from onset of symptoms until the initial percutaneous necrosectomy ( 85 days vs. 39 days ) . this longer delay may have allowed further maturation of the walled - off fluid collection , thereby allowing for a more complete and aggressive debridement per session , which facilitated fewer total sessions per patient . we had successful removal of all percutaneous drains in all but one patient with a median time to resolution of 57 days . furthermore , there were no mortalities and only one minor adverse event . in comparison with the chinese series by mui et al , the current series had a significantly higher clinical success rate ( 92 % vs. 66 % ) . we attribute this difference to their use of a small 5-mm choledochoscope , thereby limiting the extent and efficacy of debridement . several other minimally invasive interventions have been studied in the treatment of wopn , particularly direct transgastric endoscopic necrosectomy . indeed , evidence demonstrates that direct transgastric endoscopic necrosectomy is effective with superior mortality and morbidity rates when compared with surgical approaches in the management of wopn in appropriate patients 3 8 9 10 . in the gepard study , 93 patients with infected wopn underwent direct transgastric endoscopic necrosectomy with an 80 % clinical success rate 9 . however , they also experienced a 26 % adverse event rate and 7.5 % 30-day mortality rate . in another multicenter study , 104 patients with wopn underwent direct transgastric endoscopic necrosectomy with a success rate of 91 % and an adverse event rate of 14 % with one periprocedural death 10 . thus , although a transgastric approach offers excellent clinical success rates and improved safety profiles when compared with surgical approaches , the overall morbidity and mortality rates of 25 and 7 are still significant 3 . here we have demonstrated a comparable success rate , but with an improved risk profile when compared with reported rates of surgical necrosectomy and even direct transgastric endoscopic necrosectomy . we believe direct percutaneous endoscopic necrosectomy offers several advantages over the transgastric approach in certain situations . first , percutaneous access along a predefined tract avoids many of the inherent complexities of a translumenal approach , which may explain the superior safety profile reported here . second , direct percutaneous endoscopic necrosectomy can be performed using conscious sedation in an endoscopy suite rather than the general anesthesia often required for prolonged per - oral endoscopies . third , the percutaneous approach is not limited to collections with abutment to the stomach or duodenum but rather , can be utilized for any intra - abdominal fluid collection accessible to interventional radiology techniques , such as the successful bilateral hepatic abscess debridement and washout and omental necrosis debridement included in this series . first , a well - known potential adverse event of percutaneous drainage of pancreatic fluid collections is pancreaticocutaneous fistula formation , as was seen in one patient in this study . our patient experienced only mild discomfort , but these fistulas have the potential to become infected and cause long - term problems . second , one of the advantages of direct transgastric endoscopic necrosectomy is complete internalization of all hardware and close proximity of the target to the drainage site without traversing intervening bowel or abdominal vessels . in that respect , each patient is unique and , in our experience , many patients will be best served with direct transgastric endoscopic necrosectomy or rarely a surgical approach , depending on their anatomic and clinical features . third , this was a retrospective study with no control group for comparison of outcomes . finally , this complex procedure should only be performed in a tertiary care center with expert interventional endoscopists and appropriate surgical availability . despite these limitations , this is the largest us report of outcomes from direct percutaneous endoscopic necrosectomy and supports the efficacy and safety of this approach . in conclusion , direct percutaneous endoscopic necrosectomy is a safe and effective intervention for intra - abdominal fluid collections and necrosis in appropriately selected patients . this modality offers several new advantages including use of conscious sedation , improved accessibility , and an excellent safety profile . Output:	background and study aims : direct percutaneous endoscopic necrosectomy has been described as a minimally invasive intervention for the debridement of walled - off pancreatic necrosis ( wopn ) . in this retrospective cohort study , we aimed to confirm these findings in a us referral center and evaluate the clinical value of this modality in the treatment of pancreatic necrosis as well as other types of intra - abdominal fluid collections and necrosis . patients and methods : twelve consecutive patients with wopn or other abdominal abscess requiring debridement and washout underwent computed tomography ( ct)-guided drainage catheter placement . each patient then underwent direct percutaneous endoscopic necrosectomy and washout with repeat debridement performed until complete . drains were then removed once output fell below 30 ml / day and imaging confirmed resolution . the primary endpoints were time to clinical resolution and sustained resolution at 1-year follow up . results : ten patients were treated for wopn , one for necrotic hepatic abscesses , and one for omental necrosis . the median time to intervention was 85 days with an average of 2.3 necrosectomies performed . complete removal of drains was accomplished in 11 patients ( 92 % ) . the median time to resolution was 57 days . no serious adverse events occurred ; however , one patient developed pancreaticocutaneous fistulas . ten patients completed 1-year surveillance of which none required drain replacement . no patients required surgery or repeat endoscopy . conclusions : this series supports the premise that direct percutaneous endoscopic necrosectomy is a safe and effective intervention for intra - abdominal fluid collections and necrosis in appropriately selected patients . our study demonstrates a high clinical success rate with minimal adverse events . this modality offers several potential advantages over surgical and transgastric approaches including use of improved accessibility , an excellent safety profile , and requirement for only deep or moderate sedation .
PubmedSumm118804	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: feeding on a high - calorie diet ( hcd ) causes obesity and diabetes ( vianna and coppari , 2011 ) , which are known cancer risk factors ( bianchini et al . , 2002 ; calle and kaaks , 2004 ; calle and thun , 2004 ; khandekar et al . , 2011 ) . thus , gaining a better understanding of the relationship between increased calorie intake and cancer is urgent , as it will provide insights into the mechanisms of cancer pathogenesis . increased anabolic signaling caused by hcd may explain higher cancer risk in obesity ( taubes , 2012 ) . for example , hcd increases blood levels of anabolic citokines ( e.g. , insulin , insulin - like growth factors , and leptin ) that are known to promote tumor growth and survival by signaling via the pi3k - akt - mtor and ras - mapk pathways ( banks et al . , 2000 ; engelman , 2009 ; schubbert et al . , 2007 ; vansaun , 2013 ; zoncu et al . , 2011 ) . another well - established event associated with hcd is the increased inflammatory ( e.g. , tnf- ) signaling , which is also known to favor tumorigenesis ( park et al . , 2010a ) . lung cancer is the leading cause of cancer - related death worldwide , with non - small cell lung cancer ( nsclc ) representing almost 85% of all cases . activating mutations of the proto - oncogene kras ( mutant kras ) occur in 30% of nsclc cases ( pylayeva - gupta et al . , 2011 ) . mutant kras - driven tumors are associated with an aggressive phenotype , resistance to therapy , and poor outcome ( pao et al . , 2005 ) . the results from epidemiological studies assessing the effect of obesity on lung cancer risk are still inconclusive ( calle and kaaks , 2004 ; dahlberg et al . , 2013 ; leung et al . , 2011 ; yang et al . , 2013).yet , calorie restriction exerts a robust anti - tumor effect on kras - driven lung cancer in rodents ( kalaany and sabatini , 2009 ) , indicating that this type of tumor is sensitive to dietary changes . however , preclinical studies assessing kras - driven lung tumorigenesis in the context of increased calorie intake are missing . we reasoned that if hcd feeding interferes with kras - driven lung tumorigenesis , then the study of this contextual effect could be exploited to unmask key cancer vulnerabilities . hence , we assessed the impact of hcd feeding on kras - driven lung tumors in mice . to comprehensively analyze the effect of hcd feeding on lung tumors in vivo , we fed genetically modified mice that develop kras - driven lung tumors ( i.e. , kras mice ) with hcd starting before or after tumor onset . kras mice were obtained by breeding a transgene encoding kras under the control of the tetracycline operator ( tet - op - kras ) to a transgene expressing the reverse tetracycline transactivator in the respiratory epithelium under the control of the clara cell secretory protein promoter ( ccsp - rtta ) . the resulting bi - transgenic kras mice develop lung cancer with 100% penetrance following continuous doxycycline ( doxy ) administration ( fisher et al . , 2001 ) . the effect of the different dietary treatments on lung tumors was assessed by comparing neoplastic lesion profiles between three groups : ( i ) kras mice constantly fed a standard diet ( sd kras group ) , ( ii ) kras mice switched and maintained on a hcd starting 4 weeks after tumor induction ( hcd - post - tumor - onset kras group ) , and ( iii ) kras mice switched and maintained on a hcd starting 12 weeks before tumor induction ( hcd - pre - tumor - onset kras group ) ( figure 1a ) . in all groups tumorigenesis was induced at the age of 18 weeks by doxy treatment , and endpoint analyses were performed at the age of 29 weeks ( figure 1a ) . hcd - pre - tumor - onset kras mice ( 18 and 29 weeks old ) had increased body weight , hyperinsulinemia , and hyperleptinemia , while these parameters were all normal in hcd - post - tumor - onset kras mice compared to age - matched sd kras mice . however , at the age of 29 weeks both hcd - fed groups displayed increased hepatic lipid accumulation ( figures s1a s1c , available online ) . strikingly , endpoint analysis of the lungs revealed opposite effects of the two different hcd feeding regimens on neoplastic lesions . the hcd - post - tumor - onset kras mice had a significant increase in tumor burden owing to increased tumor size and number , while hcd - pre - tumor - onset kras mice had these parameters significantly reduced compared to those of sd kras mice ( figures 1b and 1c ) . notably , the tumor burden- , size- , and number - suppressing effect of pretreatment with hcd applied to both genders ( figures 1b , 1c , and s1d ) . histopathological examination indicated that neoplastic lesions from all groups were adenomas ( figure 1b).yet , lesions from hcd - post - tumor - onset kras mice were distinguished by the presence of nests of cells containing large atypical nuclei ( figure 1b ) , indicating a more advanced tumor grade . next , we set out to determine the underlying mechanism of hcd effect on tumor growth . as the tumor formation and maintenance in kras mice is strictly dependent on oncogenic kras expression ( fisher et al . , this parameter was similar between groups ( figure s1e ) , hence ruling out the idea that the different tumor growth observed between groups was the consequence of dietary effects on kras expression . changes in tumor growth could be the result of altered cellular death , altered cellular proliferation , or both . notably , while the status of apoptosis markers ( assessed by tunel assay and immunostaining for cleaved caspase-3 ) was unchanged ( figures s1f and s1 g ) , the expression levels of proliferation markers ( p - h3 and cyclin - d1 ) were significantly reduced in tumors of hcd - pre - tumor - onset compared to sd kras mice ( figures 1d and s1h ) . conversely , cellular proliferation was increased in hcd - post - tumor - onset compared to sd kras mice ( figure 1d ) . for instance , inflammation caused by dietary obesity is an effective tumor promoter in a model of hepatocellular carcinoma ( park et al . , 2010a ) . in addition , recent studies have shown that chronic pancreatitis is required for kras - induced pancreatic ductal adenocarcinomas in adult mice ( guerra et al . , 2007 ) . therefore , nongenetic events associated with hcd feeding could modulate tumor initiation when the latter is driven by a defined oncogenic mutation including kras ( guerra et al . notably , lungs of sd or hcd - pre - tumor - onset kras mice treated with doxy for 4 weeks had no differences in tumor size and multiplicity ( figure s1i ) . combined , these findings indicate that hcd feeding imposed before tumor onset affects tumor progression rather than initiation . collectively , our results show that hcd feeding started before or after tumor onset can inhibit or promote kras - driven lung tumorigenesis by mechanisms that involve suppression or enhancement of cellular proliferation , respectively . we uncovered a surprising and potent anti - tumor effect of hcd imposed before tumor onset . this finding prompted us to look for the underlying mechanism because it could unveil key vulnerabilities of kras - driven lung tumors . to this end , we first analyzed the activation status of anabolic signaling pathways known to promote tumorigenesis and be altered in the context of increased calorie intake ( i.e. , akt , erk , and stat3 ) ( banks et al . 2007 ; taubes , 2012 ; vansaun , 2013 ; zoncu et al . , 2011 ) . for instance , chronic hcd feeding induces systemic insulin resistance characterized by reduced insulin / akt signaling in metabolically relevant tissues ( ramadori et al . , 2011 ) . thus , reduced akt signaling in tumors from hcd - pre - tumor - onset kras mice could in principle explain the reduced neoplastic growth . however , while we found reduced insulin - induced phosphorylation of akt , the basal level of phosphorylated akt and of one of its downstream targets ribosomal protein s6 was similar between tumors of hcd - pre - tumor - onset and sd kras mice ( figures s2a and s2b ) . these data suggest that exacerbated insulin resistance in tumors of hcd - pre - tumor - onset kras mice is not sufficient to dampen basal akt signaling . also , the status of phosphorylation and thus activation of erk and stat3 signaling was unchanged in hcd - pre - tumor - onset compared to sd kras mice ( figure s2b ) . an expected consequence of chronic hcd feeding is increased inflammatory signaling . indeed , we found that the serum level of the proinflammatory cytokine interleukin-6 ( il-6 ) and the mrna level of intracellular inflammatory readouts ( e.g. , ik- and tnf- ) were elevated in tumors of hcd - pre - tumor - onset compared to sd kras mice ( figures s2c s2e ) . collectively , the aforementioned results suggest that changes in basal akt , erk , stat3 , or inflammatory signaling are likely not underlying the antiproliferative effects of nutritional overload on kras - driven lung tumors . next , we assessed whole - genome expression profile of microdissected lung tumors and found a significantly reduced expression of chaperones in lung tumors of hcd - pre - tumor - onset compared to sd kras mice ( figures 2a and s2f ) . er chaperones are essential for normal protein folding and key components of the er - induced upr ( upr ) , a cellular mechanism limiting the degree of er stress due to the accumulation of unfolded proteins in the er ( walter and ron , 2011 ) . thus , we hypothesized that tumor cells in hcd - pre - tumor - onset kras mice may be unable to mount an effective upr . to directly address this idea , we further characterized the status of the upr in tumors of these mice . x - box binding protein 1 ( xbp1 ) is an essential component of the upr , and in response to er stress it is spliced to produce the nuclear - localized active transcription factor xbp1s ( walter and ron , 2011 ) . similarly , chronic hcd feeding induced xbp1 mrna splicing in lung tumor tissue of hcd - pre - tumor - onset kras , as indicated by increased and decreased xbp1s and xbp1-unspliced ( xbp1-u ) mrnas , respectively ( figure 2b ) . however , despite the increased amount of cytosolic xbp1s , the amount of nuclear xbp1s was lower in lung tumors of hcd - pre - tumor - onset compared to sd kras mice ( figure 2c ) . this result is in line with the reduced mrna level of the er chaperones erdj4 , p58ipk , pdia3 , and hedj ( which are known transcriptional targets of xbp1s ) in tumors of hcd - pre - tumor - onset compared to sd - fed kras mice ( figure 2d ) . consistently , protein content of the same chaperones was also reduced ( figure 2e ) . collectively , these results indicate a defective upr in tumors of hcd - pre - tumor - onset mice . to independently assay er stress level , we measured the status of several er stress transducers . our data show that the phosphorylation level of eukaryotic translational initiation factor 2 ( eif2 ) , of er transmembrane kinase / endoribonuclease ( rnase ) ire1 , and activation of c - jun n - terminal kinase ( jnk ) , all of which are found to be increased upon er stress ( ozcan et al . , 2004 ; ozcan et al . , 2006 ) , were significantly higher in tumors of hcd - pre - tumor - onset compared to sd - fed kras mice ( figure 2f ) . notably , increased p - eif2 is expected to lead to cell - cycle attenuation or even arrest in proliferating cells ( ranganathan et al . , 2008 ; ron , 2002 ) , a result consistent with reduced tumor proliferation in hcd - pre - tumor - onset kras mice ( figures 1d and s1h ) . interestingly , mrna level of another component of the upr , and a major component of the er stress - mediated apoptosis pathway , c / ebp homologous protein ( chop ) was downregulated in tumors of hcd - pre - tumor - onset compared to sd kras mice ( figure 2 g ) . these data are consistent with reduced expression of death receptor-5 ( dr5 ) ( figure s2 g ) , a transcriptional target of chop and an important mediator of er - stress - mediated apoptosis ( lu et al . , 2014 ) . chop regulates er - stress - induced apoptosis also by repressing bcl2 gene expression ( szegezdi et al . , 2006 ) whose expression was similar in tumors of the different dietary groups ( figure s2 g ) , another result that does not support chop - induced activation of apoptotic signaling . we suggest that reduced chop expression may explain , at least in part , why unresolved er stress does not lead to apoptosis in tumors of hcd - pre - tumor - onset kras mice . healthy lung tissue ( tumor free ) from hcd - pre - tumor - onset kras mice had increased er stress compared to sd controls , as determined by xbp1s , p - eif2 , and p - ire1 level ( figures s2h and s2i ) . however , the increased nuclear accumulation of xbp1s and the increased expression of er chaperones and chop ( figures s2j s2l ) indicated normal upr activation in this tissue . notably , the levels of the aforementioned er stress and upr activation markers and xbp1s protein contents were not different between tumors from hcd - post - tumor - onset and sd kras mice ( figures s2m s2q ) . altogether , our data indicate a tumor - specific defect in er chaperone expression in lungs of kras mice that strongly depends on the time hcd feeding is initiated relative to tumor onset . chaperones are also essential for the mitochondrial - induced upr ( upr ) , a response aimed at maintaining proper protein folding in the mitochondrial matrix ( pellegrino et al . , 2013 ) . upr is activated when mitochondrial protein balance is disrupted and is associated with mitochondrial and nuclear gene expression imbalance ( mouchiroud et al . , 2013 ; pellegrino et al . , our data show reduced expression of mitochondrial matrix chaperones in tumors of hcd - pre - tumor - onset kras mice compared to their lean controls ( figure s2r ) . however , no changes in the ratio between nuclear dna - encoded atp5a1 and mitochondrial dna - encoded mtco1 ( figure s2s ) were observed . moreover , level of protein carbonylation and expression of detoxification enzymes catalase ( cat ) and superoxide dismutase 2 ( sod2 ) did not differ between tumors from different dietary groups ( figures s2 t and s2u ) , indicating a similar level of reactive oxygen species . these results suggest that reduced expression of mitochondrial chaperones in tumors of hcd - pre - tumor - onset compared to sd kras mice did not cause significant changes in upr and mitochondrial function ; hence , it is not likely to be the reason for the anti - tumor effect of hcd feeding . collectively , our data indicate that hcd feeding started before tumor onset causes impaired upr response and consequentially unresolved er stress in kras - driven lung tumors . our results prompted us to directly test whether the anti - tumor action of hcd on kras - driven lung tumors is the result of unresolved er stress . if unresolved er stress underlies the antiproliferative effect of hcd feeding , its rescue in hcd - pre - tumor - onset kras mice should boost tumor growth to a level similar to that of sd kras mice . administration of chemical chaperones , such as taurorsodeoxycholic acid ( tudca ) or 4-phenyl butyric acid ( 4-pba ) , resolves er stress induced by increased calorie intake ( ozcan et al . , 2006 ) . thus , we tested whether treatment with tudca or 4-pba reverses the anti - tumor action of hcd on kras - driven lung tumors . during the last 2 weeks of doxy treatment , hcd - pre - tumor - onset kras mice were additionally treated daily with tudca ( or saline ) ( figure 3a ) . while tumor burden was again significantly reduced in saline - injected hcd - pre - tumor - onset compared to sd kras mice , it was comparable between these groups following tudca administration ( figures 3b and 3c ) . the increased tumor burden in tudca - injected hcd - pre - tumor - onset kras mice was the result of increased tumor size , but not tumor number ( figure 3c ) . tumor burden , number , and size were not affected by tudca administration in sd kras mice ( figures 3b and 3c ) . pharmacokinetic assessments revealed a similar level of tudca accumulation in lung tumors between the different dietary groups ( figures s3a and s3b ) . moreover , the treatment of hcd - pre - tumor - onset kras mice with tudca resulted in attenuation of er stress to a level similar to that of sd kras mice , as evidenced by expression of er stress markers ( figures 3d , 3e , and s3c ) . these effects were not secondary to changes in body weight , insulinemia , and leptinemia , as these parameters were not different between tudca - treated and saline - treated hcd - pre - tumor - onset kras mice ( data not shown ) . in line with the fact that chronic hcd feeding caused reduced cellular proliferation ( figures 1d and s1h ) , tudca reversed the antiproliferative effect of chronic hcd pretreatment on kras - driven lung tumors , as indicated by increased expression of p - h3 ( figure 3f ) . notably , the tumor - proliferating effect of tudca was not associated with changes in mitochondrial : nuclear gene expression ratio ( figure s3d ) or in protein carbonylation level ( figure s3e ) . similar treatment with another structurally unrelated chemical chaperone 4-pba ( figure s3f ) essentially reproduced the effect of tudca by relieving er stress and partially rescuing proliferation and growth of tumors of hcd - pre - tumor - onset kras mice ( figures s3g s3i and data not shown ) . altogether , our data indicate that chronic hcd feeding impairs upr and consequently causes unresolved er stress that hinders the growth of kras - driven lung tumors . our data suggest that the inhibition of er chaperones whose expression is negatively affected by hcd pretreatment may represent an effective antiproliferative therapeutic avenue against kras - driven lung cancer . a major drawback of current treatments against kras - driven lung cancer is the toxic side effects of the drugs due to the lack of selectivity between cancer and normal cells . therefore , we reasoned that an ideal target against kras - driven lung cancer could be an er chaperone expressed in tumor lesions but not healthy parenchyma . in order to determine a candidate target , we analyzed our microarray data searching for chaperones that are ( i ) a resident of the er , ( ii ) significantly downregulated in tumors of hcd - pre - tumor - onset kras mice compared to sd controls , and ( iii ) specifically expressed in tumor lesions . we found several er chaperones downregulated in tumors of hcd - pre - tumor - onset kras mice ( figure s2f ) . one of them , namely fkbp10 , has been reported not to be expressed in lung during adulthood ( lietman et al . , 2014 ; patterson et al . , 2000 ) . our data indicate that fkbp10 is ( i ) expressed in tumors of kras mice , ( ii ) reduced in tumors of hcd - pre - tumor - onset mice compared to their sd controls , and ( iii ) barely detectable in normal lung parenchyma ( figure 4a ) . therefore , fkbp10 could be an ideal cancer - selective target against kras - driven lung tumorigenesis . next , we assessed the significance of fkbp10 in human lung cancer cell lines and found that it is required for proliferation of lines bearing kras mutation or mutations different from kras ( i.e. , egfr or pi3k oncogenic mutations ) ( figures 4b and 4c ) . our in vivo data also show that knockdown of fkbp10 is sufficient to hinder tumor growth ( figure 4d ) . this anti - tumor effect is caused by reduced cellular proliferation , as determined by reduced cyclin - d1 and p - h3 ( figures 4e and s4a ) , and not an increased rate of apoptosis ( figure s4b ) . notably , our data indicate that the antiproliferative effect of fkbp10 knockdown is not restricted to lung cancer cell lines but extends to cancer cells derived from other tissues ( i.e. , breast and pancreas ) ( figures s4c and s4d ) . to add translational value to our preclinical studies , we assessed expression of fkbp10 in surgically collected human lung samples containing tumor lesions and healthy parenchyma . importantly , our results indicate that fkbp10 is expressed in kras - positive and -negative lung carcinoma , but not in healthy lung parenchyma ( figures 4f and 4 g ) . collectively , our data suggest that inhibition of fkbp10 is a promising avenue to selectively hinder lung cancer growth while sparing healthy lung tissue function . in fact , we demonstrate that if hcd starts before tumor onset it dampens growth of kras - driven lung tumors ( figures 1a1c ) . however , an opposite outcome is caused by hcd starting after tumor onset ( figures 1a1c ) . hence , the anti - tumor effect is not due to the diet per se but depends on when hcd feeding is initiated relative to tumor onset . our results indicate that impaired upr underlies , at least in part , the anti - tumor action of hcd imposed before tumor onset . we suggest that a contributor to impaired upr is the poor cytosol - to - nucleus translocation of xbp1s , a defect consistent with insulin resistance in tumors of hcd - pre - tumor - onset compared to sd kras mice ( figure s2a ) ( lee et al . , 2011 ; park et al . , 2010b , 2014 ) . why does hcd feeding imposed before tumor onset hinder tumor progression but not tumor initiation ( figures 1b , 1c , and s1i ) ? we propose that this could be explained , at least in part , by an effect of the hcd on tumor vascularization , as cd31-positive cells were found to be diminished in tumors of hcd - pre - tumor - onset mice compared to the sd kras mice ( g.r . in fact , this difference may not lead to relevant effects at the initial stage of the tumorigenesis ( when tumor lesions are sufficiently vascularized by the vessels in the parenchyma ) but may become a limiting factor for further tumor progression , a hypothesis that warrants future experimental testing . first , our data suggest that inhibition of chaperones downregulated by hcd pretreatment ( e.g. , fkbp10 ) may reduce kras - driven lung tumor growth . second , our data suggest that tudca or pba treatment improves er stress , therefore leading to increased growth of already - formed kras - driven lung tumors in the context of obesity . because tudca and pba are currently undergoing evaluation ( http://clinicaltrials.gov identifiers : nct00771901 , nct01877551 ) on insulin - resistant subjects ( a population typically also affected by increased body adiposity ) , our results caution for evaluation of cancer risk in these patients . it is important to note that we have studied the effects of relatively short - term hcd on kras - driven lung tumors . thus , long - term outcomes and the contribution of obesity and/or other metabolic defects caused by hcd to tumor behavior remain to be evaluated . also , while our pharmacological data shown in figures 3a3f and s3a s3i suggest that unresolved er stress underlies reduced tumor growth in hcd - pre - tumor - onset kras mice , further genetic studies will be needed to fully dissect the underpinning mechanisms . lastly , our data warrant thorough epidemiological assessment of lung cancer risk in obese people . in summary , we unveiled an anti - tumor effect of hcd feeding on kras - driven lung tumorigenesis . unresolved er stress owing to impaired upr underlies , at least in part , the anti - tumor action of hcd . hence , we propose that this vulnerability of kras - driven lung tumors could be targeted for therapeutic purposes ccsp - rtta / tet - op - k - ras mice ( fvb / sv129 mixed background ) were generated as previously described ( konstantinidou et al . , 2013 ) and housed in groups of 45 with food ( either sd or hcd ; d12331 from research diets ) and water available ad libitum in light- and temperature - controlled environments . drinking water was supplemented with doxycycline at the concentration of 200 g / ml . tudca was administered by intraperitoneal injection ( 250 mg / kg at 8 a.m. and 250 mg / kg at 8 p.m. ) . 4-pba was administered at the same time points ( 500 mg / kg ) by oral gavage . care of mice at utsw medical center at dallas and at university of geneva was within the procedures approved by institutional animal care and use committee and by the animal care and experimentation authorities of the canton of geneva , respectively . xenograft experiments were performed by subcutaneous inoculation of cells into 8-week - old male scid mice . these procedures were performed as previously described ( konstantinidou et al . , 2013 ) . clinical data were collected at universit politecnica delle marche from samples from patients who signed a waiver of authorization . gene expression profiles were obtained from microdissected lung tumors using mousewg-6 v2.0 expression beadchips ( illumina ) . plko vectors ( open biosystems ) were used to produce recombinant lentiviruses using transit-293 t mirus reagent following manufacturer s instructions . human cell lines a549 , h596 , h1650 , aspc , and mda - mb231 were transduced as previously described ( konstantinidou et al . , 2013 ) . levels of carbonylated proteins were determined by elisa ( enzo life sciences ) following manufacturer s instructions . analytical assay of plasma , lung , and tumor samples was performed using a qtrap 4000 lc - ms / ms system . two - tail unpaired student s t test or one - way anova ( tukey s post test ) was used when comparing two groups or more than two groups , respectively . Output:	summarydietary effects on tumor biology can be exploited to unravel cancer vulnerabilities . here , we present surprising evidence for anti - proliferative action of high - calorie - diet ( hcd ) feeding on kras - driven lung tumors . tumors of mice that commenced hcd feeding before tumor onset displayed defective unfolded protein response ( upr ) and unresolved endoplasmic reticulum ( er ) stress . unresolved er stress and reduced proliferation are reversed by chemical chaperone treatment . whole - genome transcriptional analyses revealed fkbp10 as one of the most downregulated chaperones in tumors of the hcd - pre - tumor - onset group . fkbp10 downregulation dampens tumor growth in vitro and in vivo . providing translational value to these results , we report that fkbp10 is expressed in human kras - positive and -negative lung cancers , but not in healthy parenchyma . collectively , our data shed light on an unexpected anti - tumor action of hcd imposed before tumor onset and identify fkbp10 as a putative therapeutic target to selectively hinder lung cancer .
PubmedSumm118805	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: the totally extraperitoneal ( tep ) method is essentially a laparoscopic modification of stoppa 's repair . we report a case of pneumomediastinum and subcutaneous emphysema of the neck , without pneumothorax , after tep repair . a 52-year - old man , american society of anesthesiologists ( asa ) level i , 75 kg , 173 cm , with left indirect groin hernia was admitted for elective inguinal repair using the tep operation . after an uneventful intubation , tep repair of the hernia utilizing three midline trocars technique was performed . at the beginning of the procedure , so2 was 98% , blood pressure 140/65 and fetco2 was 34 mm hg . operation time was 32 minutes , with a mean intra - abdominal pressure of 11 - 12 mm hg . during the procedure , immediately after extubation , the patient had severe chest pain , o2 saturation decreased to 84% , fetco2 increased to 44 mm hg , and subcutaneous emphysema of the neck was detected . there was no emphysema of the abdomen or of the back . a chest film and thoracic computed tomographic ( ct ) scan ( figure 1 ) confirmed the presence of pneumomediastinum without pneumothorax . after two hours of mechanical ventilation , the emphysema resolved , and the patient was extubated without any problem . theoretical advantages of laparoscopic hernioplasty are less pain and a quicker return to normal activity . complications of tep laparoscopic hernioplasty are reported infrequently . bowel , bladder and vessel injuries , bleeding in the preperitoneal space , severe testicular pain , hemoscrotum or nerve entrapment noted with tep hernioplasty have also have been described in open procedures . the detractors of lh mainly criticize the laparoscopic approach as usually being performed under general anesthesia with higher costs and an unknown recurrence rate . however , large series have been published showing a low recurrence rate ( 0% - 1% ) . tep repair is performed by dissecting the preperitoneal space and insufflating carbon dioxide to maintain an operative space without pneumoperitoneum . this method potentially avoids the risks of intra - abdominal organ lesions and peritoneal adhesions . air may enter the mediastinum from the esophagus , trachea , bronchi , lung , neck , abdomen or retroperitoneal space , producing mediastinal emphysema or pneumomediastinum . co2 usually passes through the hiatus secondary to a congenital anomaly , weak points , defects or a tear in the diaphragm . high - working co2 pressure or a prolonged insufflation time can also lead to pneumomediastinum . a recent article described a tep procedure complicated by hypercarbia and the development of massive subcutaneous emphysema without hemodynamic instability . this was thought to be due to a high intra - abdominal insufflation pressure that ranged between 14 and 18 mm hg . it is thought that pneumothorax as a complication of tep is most likely related to high insufflation pressure and the length of the procedure , itself . both cases occurred in healthy patients without hiatal or diaphragmatic hernia , and the condition was solved without the placement of a chest tube . a retroperitoneal route could be postulated on extraperitoneal procedures , but no retroperitoneal air was present on ct , and no back emphysema was detected . in our case , a hiatal route is the most reasonable explanation for the occurance of pneumomediatinum as insufflation time was short , working pressure was low , and bronchoscopy ruled out an airway disruption . we conclude that pneumomediastinum can occur after extraperitoneal laparoscopic hernia procedures due to small tears in the peritoneum that occur even with low - working pressures . Output:	a 52-year - old man with left indirect groin hernia was admitted for elective inguinal repair using the totally extraperitoneal ( tep ) approach . after an uneventful intubation , tep repair of the hernia was performed with three midline trocars . immediately after extubation , the patient noted severe chest pain . there was a decrease in pao2 saturation , and neck subcutaneous emphysema was detected . there was no emphysema of the abdomen or of the back . a chest film and thoracic computed tomographic ( ct ) scan confirmed the presence of pneumomediastinum without pneumothorax . the patient was discharged without complications .
PubmedSumm118806	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: depression in older people has been reported to differ from that in younger people because of their preoccupation with physical health problems , which can lead to a risk that the depression will not be diagnosed and that the patient will not seek further help [ 14 ] . in addition , nurses and healthcare professionals frequently believe that depressed older persons ' physical health problems are not real but a sign of depression . a possible consequence is that older persons with physical health problems and deprssion are misunderstood , discriminated against and abandoned by the healthcare system . pain can give rise to physical incapacitation followed by depression due to reduced physical and social activities [ 5 , 6 ] . . found that painful physical symptoms are associated with major depressive disorder and influence help seeking as well as use of medication . suen and tusaie reported that depressed persons exhibited guilt , sadness , anger , resentment , loneliness , helplessness , hopelessness , inability to enjoy activities , and anhedonia . according to these authors , depressed elderly persons should be given time to express their emotional pain and distress , as they are capable of separating their mental state from their pain and physical health problems . other studies have revealed that depressed older persons feel alienated from themselves and others , whose experiences pervade their whole life world , involving both body and soul . suffering from physical health problems has also been described as leading to an increased risk of suicide in older people [ 10 , 11 ] . do depressed elderly persons experience stigma when it is believed that their physical health problems are not real but a symptom of depression ? stigma occurs when a person perceives that he / she is ignored and has been defined as a process whereby certain individuals and groups are unjustifiably rendered shameful , excluded , and discriminated against . stigmatising attitudes towards people with a range of mental disorders including depression have been investigated in studies undertaken in several countries . one form of stigma is diagnostic overshadowing , defined as the misattribution of physical symptoms to a preexisting mental disorder . beliefs about and attitudes towards people with such disorders and the desire for social distancing have been explored [ 16 , 17 ] . experiences of discrimination ( i.e. , the behavioural aspects of stigma ) have only been addressed in a few studies , until recently the focus was on serious mental illness , such as schizophrenia . . contributed to the understanding of depression - related discrimination by assessing the nature and severity of experienced and anticipated discrimination reported by over 1,000 persons with depression in 35 countries . however , sirey et al . found that although younger patients perceived more stigma than their older counterparts , it only predicted treatment discontinuation among the latter . a study by roeloffs et al . described stigma as being related to a number of chronic medical conditions , in addition to age , gender , ethnicity , and social support . . revealed that a national time to change programme against stigma and discrimination was successful in improving attitudes and behaviour but not knowledge among the general public in england . stigma has been described as leading to the development of negative attitudes towards older persons such as prejudices , ageism , the creation of popular stereotypes and taboos , damaging self - beliefs , lack of public discussion , and alarmist popular and professional statements about burden and costs . according to sartorius , stigma leads to discrimination in the provision of services for physical health problems in older people with mental disorders . thus , older people with a mental disorder carry a double burden , which merits special attention in order to prevent stigma and discrimination . even when municipal resources are available to support older persons who suffer from mental ill health , such individuals do not always seek care . in 2012 and 2013 , our research team conducted exploratory studies on data collected from in - depth [ 25 , 26 ] interviews with depressed elderly persons from different parts of norway . the result revealed that isolation and refusal to make use of available municipal resources mean that older persons with mental ill health suffer in silence [ 25 , 26 ] . we explored depressed elderly persons ' experiences of physical health problems because during the in - depth interviews the participants mentioned such problems in connection with depression . to deepen the understanding of depressed elderly persons ' lived experiences of physical health problems . the study has an interpretive hermeneutic approach with in - depth interviews as the data collection method . the participants comprised two men and thirteen women from the east and west coast of norway . the inclusion criteria were persons diagnosed with a depressive or mood disorder , able to understand and speak the norwegian language , resident in a community in norway , referred to community healthcare during the previous six months , are over 60 years of age , and willing to speak about their experiences . fourteen of the participants had been admitted to psychiatric hospitals where two were diagnosed with bipolar disorder . data collection took place in community mental health centres in the east and west of norway attended by patients with depression or a mood disorder . in 2011 , a nurse manager in the community contacted the participants by telephone to arrange a date and time for an individual interview , which was held either in their own home or in the office of the first ( alh ) or the second author ( al ) . the interview took the form of a dialogue between the interviewer and the participant where the interpreted meanings constituted the results . the authors encouraged the participants to narrate about their physical health problems and how they influenced everyday life . 15 statements describing physical health problems were compiled in a table ( table 1 ) . the interviews , which lasted between 60 and 120 minutes were audio - taped and transcribed verbatim . approval for the study was granted by the regional ethics committee of western norway ( no . 2010/2242 ) . the interviews were conducted in a sensitive manner so as not to increase the depressed elderly persons ' feelings of powerlessness and helplessness . they were provided with detailed written information andtheysigned a consent form and were assured that their name and identity would not be disclosed and that they had the right to withdraw at any time . hermeneutic analysis means reflecting on one 's understanding and the knowledge on which the analysis is based . it follows the hermeneutic principle of moving from the whole to the parts and back to the whole . the authors reflected on the transcribed text and discussed divergent interpretations on several occasions before finally achieving consensus . understanding the whole text can constitute a starting point for an analysis of its meaning in relation to a new aim or question . sentences related to the aim were identified and grouped in a table alongside relevant abstractions , which formed the foundation of the search for themes representing the underlying meaning . the first author ( alh ) reread the text to ensure that it had been correctly transcribed and that nothing was excluded . one main theme was identified , which represented our understanding of the abstracted content of the participants ' statements . the hermeneutic circle is an essential tool for achieving new understanding and as researchers we experienced it as a back and forth movement between the whole and the parts of the interview text . every sentence was related to the text as a whole in order to capture new meanings and expand the overall meaning ( table 2 ) . the researchers reflected on , revised , discussed , and abstracted the text on several occasions , finally managing to identify a shared understanding that is intended to describe the participants ' experiences . as this study has a hermeneutic approach , it is important to establish trustworthiness , for which various strategies exist [ 29 , 30 ] . the themes that emerged represent an attempt to understand the meaning of physical health problems and their influence on the depressed older persons ' daily life . the epistemological notion was that the researchers and informants are interrelated and they interact with each other . the researchers influenced each other by discussing their reading and interpretation of the text on several occasions as well as by being flexible and changing the theoretical perspective throughout the analysis , which is related to the concept of dependability . we did not try to distance ourselves but attempted to treat the data in a neutral manner in accordance with the concept of confirmability . the term applicability as used by hman relates to the concept of transferability and whether the knowledge gained in this study can be transferred to a similar context . one main theme , living with stigma , and three themes emerged : longing to be taken seriously , being uncertain about whether the pain is physical or mental , and a sense of living in a war zone . the second theme comprised two subthemes : feeling like a stranger and feeling dizzy . in the third theme , several of the participants described experiences where physical health problems and depression involved living with stigma , which can be understood as an experience of being considered different from others . this difference is caused by the discrimination these persons can experience when labelled with a mental illness such as depression , which frequently increases their sense of not being taken seriously or considered deviant . when depressed , older persons also suffer from physical health problems , which the literature describes as part of depression ; healthcare providers seem to believe that the physical health problems are not real . other people behave as if the elderly persons are imagining things and that their physical health problems are due to depression . one of the participants stated;because i suffer from major depression , my gp did not believe me when i developed a prolapse , despite the x - ray examination revealing a prolapse in my neck . 1 ) because i suffer from major depression , my gp did not believe me when i developed a prolapse , despite the x - ray examination revealing a prolapse in my neck . 1 ) another participant reported that she went to two different gps , but neither of them gave her a referral for an x - ray examination , as they did not believe that her pelvis was broken . 4 ) the participants were reluctant to mention depression , as they had the impression that it made healthcare professionals ignore their physical problems . they revealed that gps did not explain why their physical health problems were not examined . one of the participants was nearly blind and related that the healthcare professionals did not believe her when she complained about the lack of insulation in her council apartment , which made the floor cold . as she suffered from ischaemia , she stated;the nurses at the centre do not believe my story and want me to take anti - depressive medication . however , the gp uses such medication to calm the old people at the centre . i refuse to take it . and the last time the older persons were invited to a party 6 ) the nurses at the centre do not believe my story and want me to take anti - depressive medication . however , the gp uses such medication to calm the old people at the centre . i refuse to take it . and the last time the older persons were invited to a party 6 ) a female participant stated that she suffered from backache as a result of osteoporosis . she was diagnosed with the condition the previous summer , which was a relief as it explained her pain . another of the participants described how she finally found a medical student who believed her and examined her for over one and a half hours . she stated;i was prescribed a medicine i was to take four times a day for 10 days . 13 ) i was prescribed a medicine i was to take four times a day for 10 days . 13 ) most of the participants reported uncertainty about whether their experiences of pain were physical or mental . every day they woke up hoping that their health would improve however , they found it impossible to plan everyday life , as the struggle between physical and emotional pain made their situation unpredictable , often exacerbated by lack of understanding on the part of the gp , other healthcare professionals , and their family members . one of the women had a pacemaker and also suffered from thyroid hormone problems , leading to fainting and hyperactivity . she related that she often argues with her gp about her situation and stated;i have read a lot about the pacemaker , and the thyroid hormone problem means that i 'm sometimes hyper , which my gp relates to depression . i have to use a laxative every day , which makes me nervous because i never know when i will have to run to a toilet . it 's awful , i wonder if all this is really related to my depression and anxiety ? 14 ) i have read a lot about the pacemaker , and the thyroid hormone problem means that i 'm sometimes hyper , which my gp relates to depression . i have to use a laxative every day , which makes me nervous because i never know when i will have to run to a toilet . it 's awful , i wonder if all this is really related to my depression and anxiety ? 14 ) uncertainty due to the absence of examinations was explained as feeling that something is physically wrong despite being assured by the gp that everything is fine . some of the participants explained that their physical pain made it almost impossible to fall asleep . at times they felt alienated from everyday life , characterized by the impression of being on the outside and not taking part in life . one of the men reported that even when he was admitted to a psychiatric hospital , he did not tell anyone about his pain . how can i explain this to another person when i do not understand it myself ? how can i explain this to another person when i do not understand it myself ? one woman who had been admitted to hospital twice because of dizziness explained;the gp told me they could not find anything wrong with me . but this was of no comfort because i 'm still dizzy and my body continues to shake . but this was of no comfort because i 'm still dizzy and my body continues to shake . 5 ) another woman revealed that she could not turn her head in any direction without pain . she stated;i can not clean my house because of the dizziness and pain in my head . 13 ) i can not clean my house because of the dizziness and pain in my head . 13 ) most of the participants revealed that they live with a sense of impending disaster similar to being in a war zone and some thought that this was related to their depression . they were often extremely sensitive about the information they received from healthcare professionals about their physical conditions . one participant narrated that the medical specialist at the hospital told her that the cancer might spread to her brain , thus increasing the risk of death.after receiving this information i felt that i was in a war zone . the specialist asked me if there was anything i wanted to do before it was too late . i often think that had i not been informed about this , my life would have been different . 13 ) after receiving this information i felt that i was in a war zone . the specialist asked me if there was anything i wanted to do before it was too late . i often think that had i not been informed about this , my life would have been different . 13 ) many of the participants stated that they were terrified and had a feeling of disaster when informed that they were seriously ill . catastrophic thoughts and feelings increased and one participant stated;one day i noticed a change in the skin above my lips . the gp told me i had skin cancer that could easily spread to my brain and eyes . the gp told me i had skin cancer that could easily spread to my brain and eyes . however , they were concerned that if they developed yet another illness it would increase their helplessness and make them dependent on others , which frightened them . one of the men stated;i have taken care of myself all my life , but after this stroke i have become more and more disabled , i can not move and have no strength in my hand . i 'm afraid of having another stroke that would make me even more helpless and dependent on others . 11 ) i have taken care of myself all my life , but after this stroke i have become more and more disabled , i can not move and have no strength in my hand . i 'm afraid of having another stroke that would make me even more helpless and dependent on others . 11 ) a female participant explained that after an ankle fracture she was sent home in a state of psychosis because nobody understood how helpless it made her.i need an operation on my hips as well but they sent me home . however , my arms are weak and i found it almost impossible to climb the stairs . 9 ) i need an operation on my hips as well but they sent me home . however , my arms are weak and i found it almost impossible to climb the stairs . 9 ) the participants were exhausted due to worrying about their children or grandchildren and sometimes did not even know what they were worrying about . one of them stated;i'm so exhausted worrying about my sons and i 'm constantly worried about everything . 8) i 'm so exhausted worrying about my sons and i 'm constantly worried about everything . according to goffman [ 31 , page 3 ] , stigma is an attribute that is deeply discrediting . stigma is due to a perception of deviating from the social norm and involves a relationship between an attribute and a stereotype . it leads to social sanctions whereby one person is labelled deviant , while another is considered normal and acceptable . the sanctions act as a social control mechanism by defining what is acceptable within a particular context . stigma is an expression of people 's responses to individuals who possess some undesirable characteristics . it can be discrediting and involve prejudicial and discriminatory practices [ 32 , 33 ] . in several studies stigma has been found to reduce social functioning [ 34 , 35 ] . nurses and healthcare professionals can decrease stigma by taking depressed elderly persons ' physical health problems seriously , thus alleviating their emotional pain and anxiety . the experience of stigma can involve a sense of being an outsider , where connecting with others is challenging for older persons in their struggle to make sense of their despair . depressed elderly persons ' experience of stigmatization may be a negative effect of the labelling process . the consequences of stigma for a person 's life can be as harmful as the direct effects of the disease and serve as a barrier to recovery . being treated as a person who can not be trusted can increase the feeling of inferiority and shame . a major difficulty in overcoming stigma , and probably one of its causes , is that it is next to impossible for those who have not experienced depression to understand the extent of the depressed elderly person 's suffering . wolpert [ 39 , page 223 ] stated that it may be too difficult to understand and that depressed individuals are seen as unpredictable persons who , if they really tried , could pull themselves together . it is difficult to believe what such unpredictable persons say about their physical health problems . research has revealed that support from others can serve as a buffer against the development of depression and facilitate recovery , thus preventing isolation and withdrawal [ 38 , 39 ] . longing to be taken seriously can be related to the discrimination that is often experienced by depressed older persons . the phenomenon of diagnostic overshadowing [ 15 , 41 ] refers to the fact that high levels of physical and mental ill health in elderly persons increase the risk of not being taken seriously . they are considered different and their physical health problems as imaginary and related to depression . lack of sensitivity in the provision of information can also increase the stigma of depression . when one is made to feel that one deviates from the norm , one becomes ashamed . perceived stigma involves internal shame associated with being depressed as well as fear of stigma ; one feels unworthy . sometimes being in a depressed state can imply a lack of self - management , a sense of estrangement , and loss of togetherness . in this state , depressed persons have no strength to fight for their rights . it is an existential dimension of being in the world related to experiences of freedom and dignity . in even the most difficult situations it is possible to increase a depressed elderly person 's strength by enhancing her / his self - determination and dignity . being uncertain about whether the pain is physical or mental seemed to involve an experience of insecurity , which was exacerbated by not knowing what the day would bring in terms of physical and emotional pain . the participants became increasingly uncertain of their own experiences because who can one trust when one can not trust oneself ? uncertainty has been described in the literature as a feeling related to insecurity and distrust . the review by hansen et al . provided a synthesis of patient experiences of uncertainty in illness . the included studies revealed a sense of unpredictability when living with physical health problems such as chronic hepatitis , hiv and aids , endometriosis , and stroke . however , hansen et al . suggested that nurses and healthcare professionals need to promote the experience of control , confidence , and insight among patients . it seems that the older persons ' struggle increased their confusion , emotional pain , and distress . such painful conditions require a deeper understanding of and insight into the complex interrelated issues of soma and psyche . chou and chi found that pain was an important predictor of depression in elderly chinese primary care patients . another study revealed that older persons who experience pain are at risk of developing depression and vice versa . if one is exposed to such suffering , one can feel like a stranger , even in a familiar environment . when perceptions of physical health problems are not confirmed , an individual can become estranged from her / himself and unsure of her / his own feelings and experiences . do i have pain or are my physical health problems a figment of my imagination ? it appears that complaints of dizziness are often misunderstood by mental health professionals in primary care , who seem to perceive it as a sign of depression . however , this may be relevant , as research has revealed that a large percentage of patients presenting with dizziness develop secondary psychiatric disorders over the course of their disease . sczepanek et al . stated that little is known about the course of incident dizziness . a sense of living in a war zone can be related to anxiety and disaster associated with physical health problems , especially serious diseases such as cancer . anxiety and depression in the elderly are often related to the burden of serious illness . depression is often associated with past loss and negative thoughts about the self and the world , while anxiety is linked to future harm and danger . research has revealed that depressed older persons are capable of differentiating emotional pain and distress from physical pain . anxiety can be related to the fear and worry of being increasingly dependent on others and is understandable in the context of older persons ' existential situation . it raises the question about how long one will be able to maintain one 's autonomy and independence . depressed older persons seem to have fewer mental and social resources to distract them from catastrophic feelings about the future . research has demonstrated that they increasingly worry about many things and that the type and degree of worry vary across the life span . emotional support from adult children had a positive effect on depression and worries , while social support was important for understanding one 's catastrophic feelings about the future [ 50 , 51 ] . human beings have a desire to make sense of their life as opposed to merely solving problems . such a desire can change the focus from ill health and illness to the human being , giving a person time and space to talk about her / his previously unarticulated worries related to grief and sadness . however , older persons may be more sensitive about being taken seriously , and it does not take very much to weaken an individual 's potential and optimism . the existential dimension of being in the world need not be related to complete freedom from worries . this study revealed that depressed elderly persons who suffer from physical health problems are vulnerable as they seem to have a double burden due to experiencing negative attitudes , discrimination , and stigma . nursing practice must provide information in a sensitive way and always ascertain whether physical health problems are real as opposed to a sign of depression . due to the cost of clinical interventions , depressed older persons pose a difficulty as they constitute a group with many physical health problems . it is necessary to develop an action plan to address their physical health problems because physical diseases increase in old age . this study highlighted the fact that discrimination means any distinction , exclusion , or preference that has the effect of nullifying or impairing equal enjoyment of rights . thus such individuals must be taken seriously in order to lessen the burden of stigma . according to martinez - arn et al . depressed or depressive has consequences such as sanctions associated with fear and lack of understanding on the part of society . the problem of diagnostic overshadowing must be investigated and educational interventions developed to target it . it is important to establish a consensus among general practitioners , nurses , and health care professionals about how to address these issues . de mendona lima suggested that coordinated efforts are necessary to reduce stigma and discrimination among older persons who suffer from mental disorders . now is the time to develop more coordinated efforts and to employ a range of research approaches . nurses and healthcare professionals need to address prejudices and negative attitudes towards depressed older persons , especially if having the impression that the person in question is trying to explain her / his struggle by means of physical health problems . reducing stigma has been on the agenda for at least ten years in most countries . a greater understanding and acceptance of depressed older persons with physical health problems is necessary . nurses and healthcare professionals need more education about how negative self - beliefs held by those who are or might be stigmatised can increase shame , low self - esteem , and unwillingness to discuss problems or access services . effective training programmes and procedures should be developed with greater focus on how to handle depressive ill health and physical problems in older people . more research is required on nonstigmatising treatment and care for depressed older persons with physical health problems and pain . Output:	the aim of this paper is to deepen the understanding of depressed elderly persons ' lived experiences of physical health problems . individual in - depth interviews were conducted with 15 depressed elderly persons who suffer from physical health problems . a hermeneutic analysis was performed , yielding one main theme , living with stigma , and three themes : longing to be taken seriously , being uncertain about whether the pain is physical or mental , and a sense of living in a war zone . the second theme comprised two subthemes , feeling like a stranger and feeling dizzy , while the third had one subtheme : afraid of being helpless and dependent on others . stigma deprives individuals of their dignity and reinforces destructive patterns of isolation and hopelessness . nurses should provide information in a sensitive way and try to avoid diagnostic overshadowing . effective training programmes and procedures need to be developed with more focus on how to handle depressive ill health and physical problems in older people .
PubmedSumm118807	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: the european guidelines for the management of bleeding in the trauma patient recently reported by spahn and coworkers is a multidisciplinary , multi - institutional , evidence - based , consensus - driven approach to the diagnosis and management of bleeding in the injured patient . although potentially susceptible to bias introduced by the authors , the grading system used is generally appropriate . the majority of the recommendations are sound and are centered around rapid control of surgical bleeding , proper resuscitation , and transfusion of red cells and coagulation factors . fittingly , the authors make their most important recommendation first ; ' the time between injury and definitive control of bleeding must be minimized . ' although seemingly obvious , in a recent study from a high - volume , mature trauma system , a common cause of preventable death was failure to identify and control surgical bleeding . however , some of the other recommendations based on less definitive data remain controversial and are not necessarily mainstream . also , some of the recommendations need to be placed in context , particularly in terms of the dynamic continuum of patient management over time . for example , the recommendation that red cell transfusion be based on a conservative transfusion trigger ( hemoglobin 7 to 9 g / dl ) is based on solid evidence . however , that evidence applies only to the stabilized ( postoperative ) patient who is no longer bleeding massively . within this context it would be unwise to await laboratory data to decide whether to transfuse an acutely bleeding patient . under such dynamic circumstances , the decision must be based on clinical factors such as vital signs , response to resuscitation , volume of ongoing bleeding , and the success of surgical attempts to control bleeding . likewise , transfusion of thawed plasma under those circumstances should not await the results of an international normalized ratio ( inr , for prothrombin time ) , but rather the decision should be based on clinical factors . once bleeding is controlled and the patient is stabilized , such strict laboratory - guided transfusion practices can be followed . in fact , recent evidence indicates that coagulation products should be infused very early , indeed pre - emptively , in the face of ongoing severe hemorrhage . in an attempt to minimize the coagulopathy associated with severe bleeding and transfusion , protocols for massive transfusion have been developed by a number of institutions as well as the us military in iraq . although the optimal ratio of blood to plasma transfusion is yet to be determined definitively , recent data suggest that this ratio is probably close to 1:1 in the patient with massive bleeding and shock . if they are eventually demonstrated to be effective , such early infusions of plasma would be given long before hemoglobin and inr tests could be performed . regardless of these types of caveats , converting evidence - based recommendations into standard day - to - day operational procedures can still leave plenty of opportunity for interpretation and resulting variability in practice . for example , recommendation 4 from the bleeding management guideline states that , ' we recommend that patients presenting with haemorrhagic shock and an identified source of bleeding undergo an immediate bleeding control procedure unless initial resuscitation measures are successful . ' for the purposes of an operational protocol , how does one define ' successful resuscitation ' ? a definition of successful resuscitation to one surgeon may still be considered a state of ongoing bleeding and continued need for transfusion by another . at the heart of this matter is the presumption that , ultimately , there is a ' best way ' to care for bleeding patients . the goal of evidence - based guidelines is to help develop recommendations not only to identify the best practice but also to decrease variability in delivery of care . however , while more definitive data are lacking , many guidelines including many of those in the present discussion must remain fairly broad in order to accommodate controversial and divergent points of view . accordingly , the european guideline should be viewed as an excellent and timely consensus , but one that will remain a work - in - progress that must continually be refined as new data are accumulated . the authors should be applauded for their tremendous initiative ; moreover , it is strongly recommended that they continue to regroup regularly in order to refine these recommendations further as permitted by the evolving evidence . Output:	the development of evidence - based guidelines has gained popularity as a strategy to reduce variation in practice and to orient clinical care around documentable best practices . based on available data , the new european guidelines for the management of bleeding in the trauma patient do deliver a number of sound recommendations . however , some issues remain controversial and , like many guidelines , the actual translation of these evidence - based recommendations into routine clinical practice protocols continues to leave opportunity for variation . nevertheless , this consensus guideline provides an excellent starting point . as evidence continues to accumulate , future iterations should provide greater specificity and move us closer to the definitive best practice .
PubmedSumm118808	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: fluid management in patients with acute respiratory distress syndrome ( ards ) is particularly difficult . in hemodynamically stable patients fluid restriction is warranted as it decreases the length of need for ventilatory support . however , at the initial phases , patients with ards also often present hemodynamic instability and are at risk of tissue hypoperfusion and even tissue hypoxia , which may further contribute to exacerbation of ards by boosting activation of inflammation and coagulation . guidance of fluid administration is often complicated by the high pleural pressures , associated with high positive end - expiratory pressure ( peep ) levels , that affect measurements of intravascular pressures . multiple studies have shown that static indices of preload , being pressures or volumes , often fail to predict the response to fluids . on the contrary , dynamic indices based on heart - lung interactions , such as pulse pressure variations ( pp ) , have repeatedly been found to reliably predict the response to fluids in mechanically ventilated patients . in patients with ards , ventilation with low tidal volume is recommended . in patients ventilated with low tidal volume , pulse pressure variations do not predict adequately the response to fluids [ 6 - 8 ] . in this issue of critical care , lakhal and lakhal and colleagues observed that pulse pressure variations moderately predicted the response to fluids and that the predictive value was equivalent to that of pulmonary artery pressure . first , this trial confirms that pulse pressure variations fail to predict fluid responsiveness in a large series of patients with ards ventilated according to current guidelines . indeed , it has been advocated that changes in pleural pressure may be preserved , as lung compliance is also reduced in ards patients . the issue is that changes in pleural pressure can not be reliably estimated from the difference between plateau and end - expiratory pressure as the transmission of pressure from airway to pleura markedly varies among patients . even selecting patients with large driving pressure failed to improve the predictive value of pp . these results are in line with the observations of valle and colleagues , who found that correcting dpp by driving pressure failed to improve the predictive value for fluid responsiveness . interestingly , in the few patients with a difference between inspiratory and expiratory pulmonary artery pressure higher than 4 mmhg , the prediction of pp was excellent ( area under the curve 1.0 ( 95% confidence interval 0.73 to 1.0 ) ) . this suggests that these indices can be used when changes in alveolar pressure are effectively transmitted to pleural pressure . unfortunately , this requires invasive measurements of intravascular pressures by pulmonary artery catheter or of esophageal pressure . another important factor may be that respiratory rate is often high when ventilating with low tidal volume . we observed that pp was negligible in fluid responders when the ratio of heart rate to respiratory rate was decreased below 3.6 by increasing respiratory rates . muller and colleagues recently confirmed that pp can be low in fluid responders when this ratio is low . lakhal and colleagues confirmed the combined influence of tidal volume and respiratory rate . using a composite index computed as the product of tidal volume by heart rate divided by respiratory rate , they observed that pp was significantly larger in responders than in non - responders only in patients with above median values of this composite index . it is important to acknowledge the limitations of pp and related indices . when applied correctly more importantly , resuscitation strategies based on these indices are associated with better hemodynamic stability and lower incidence of postoperative organ dysfunction . in patients with ards , the use of these indices is unfortunately limited by several factors , including low tidal volume , high respiratory rate and right ventricular dysfunction . Output:	respiratory - associated variations in stroke volume and pulse pressure are frequently used to predict the response to fluid administration . however , it has been demonstrated that low tidal volume ventilation may limit their use in patients with acute respiratory distress syndrome ( ards ) . in this issue , a trial investigates the value of pulse pressure variation to predict fluid responsiveness in a large series of patients with ards ventilated according to current guidelines .
PubmedSumm118809	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: this surveillance study was approved by the chairman of medical board , tan tock seng hospital ( ttsh ) , singapore . the clinical study was approved by the domain specific review board , national healthcare group , singapore . on april 25 , 2009 , singapore s ministry of health initiated containment measures in response to pandemic ( h1n1 ) 2009 . travelers returning from affected countries to singapore with acute febrile respiratory illness were screened at the ttsh emergency department , the designated screening center for pandemic ( h1n1 ) 2009 . thermal screening was conducted at all border entry points , and the mass media publicized nationwide that persons with a risk for pandemic ( h1n1 ) 2009 virus infection based on travel history , fever , and respiratory symptoms should go to the ttsh emergency department for screening . combined nasal and throat swab specimens were tested with an in - house , gel - based pcr for influenza a , h1 , h3 , h5 , n1 , and n2 . all specimens with subtype h1n1positive test results underwent in - house , probe - based influenza ( h1n1 ) 2009 pcr , and partial sequencing of the matrix gene was conducted to confirm positive pcr results . from april 27 through may 24 , 2009 , a total of 300 persons ( 244 travelers returning from affected countries with a respiratory illness and 56 symptomatic contacts ) were screened for influenza infection : 24.0% had subtype h3n2 , 1.6% had seasonal subtype h1n1 , and 2.7% had influenza b. the median age of patients was 36 years ( range 1070 years ) , and 14.7% had other illnesses ( asthma [ 52.3% of those with other illnesses ] , diabetes mellitus [ 29.5% ] , heart disease [ 11.4% ] , cancer [ 4.5% ] , and hiv [ 4.5% ] ) . fever was reported for 92.9% of all screened persons , cough for 82.4% , sore throat for 57.6% , rhinorrhea for 62.4% , myalgia for 25.9% , headache for 16.5% , and gastrointestinal symptoms for 9.4% . two thirds of the patients with influenza - positive pcr results met the criteria for influenza - like illness ( ili ) as defined by the us centers for disease control and prevention ( cdc ) ( 9 ) . patients who met these criteria were more likely than those who did not to have influenza - positive pcr results ( odds ratio [ or ] 8.1 , 95% confidence interval [ ci ] 4.614.3 , p = 0.0001 ) . compared with contacts who had no recent travel , travelers returning from north america were less likely to have influenza - positive pcr test results ( or 0.13 , 95% ci 0.060.27 , p = 0.0001 ) . to enhance detection of pandemic ( h1n1 ) 2009 , we obtained nasal and throat swab samples on may 2 and 3 , 2009 , from all hospitalized patients with clinically suspected pneumonia , regardless of their travel history . a total of 146 patients were screened , of whom 21 ( 14.4% ) were positive for influenza ; 10.3% of the 146 patients had h3n2 , 1.4% had seasonal h1n1 , and 2.7% had influenza b. the median age of these patients was 67 years ( range 2095 years ) , and their median hospital stay at screening was 1 day ( range 017 days ) . of the patients , 52% were male , and 86% had other illnesses . at the time of admission , 90% of patients had a fever , 76% had a cough , 24% had a sore throat , 52% had rhinorrhea , 24% had myalgia , and 19% had headache . findings on chest radiographs were abnormal for 10 patients ( 48% ) , of whom 5 had findings consistent with pneumonia . all but 1 patient were treated with antimicrobial drugs ; none was given antiviral drug therapy . in addition , during may 28 , 2009 , as part of nationwide enhanced influenza surveillance , nasal and throat swab specimens from patients screened at the ttsh emergency department were tested by pcr for influenza virus . the patients had fever or respiratory symptoms but no history of travel to an affected country . overall , 95 patients were screened , of whom 30 ( 31.6% ) had positive results for influenza ; 24.2% of the 95 patients had h3n2 and 7.4% had influenza b. fever was reported for 69.5% of the 95 patients , cough for 75.8% , sore throat for 56.8% , rhinorrhea for 58.9% , myalgia for 16.8% , and headache for 44.2% . of the 30 patients with pcr results positive for influenza , 22 ( 73% ) met the criteria for ili . compared with patients who did not meet these criteria , patients who did meet them were 3 more likely to have influenza - positive pcr results ( or 3.02 , 95% ci 1.177.75 , p = 0.019 ) . only 6 ( 6.3% ) of the 95 patients had self - reported influenza vaccination in the preceding 6 months . screening of patients with ili symptoms continued at the ttsh emergency department , and from may 3 through june 13 , 2009 , only seasonal influenza ( predominantly virus subtype h3n2 ) was detected . pandemic ( h1n1 ) 2009 was first detected during the week beginning june 14 , and the weekly incidence rapidly increased until the week ending july 25 , when all influenza cases were caused by pandemic ( h1n1 ) 2009 virus ( figure ) . influenza - positive test results for surveillance samples obtained at the emergency department , tan tock seng hospital , singapore , may 3july 25 , 2009 . an epidemiologic week starts on a sunday and ends on a saturday ( e.g. , week 18 started on may 3 and week 29 on july 19 ) . * by july 25 , 2009 , a total of 838 patients with pandemic ( h1n1 ) 2009 virus infection had been seen at the ttsh emergency department . fever was reported for 85.3% , cough for 87.2% , sore throat for 55.4% , rhinorrhea for 41.6% , myalgia for 11.1% , and headache for 11.0% ; 57% of patients met the cdc criteria for ili . patients with pandemic ( h1n1 ) 2009 were significantly younger ( p = 0.0001 ) than patients with seasonal influenza , but the proportion with ili in each group was similar ( or 0.65 , 95% ci 0.411.04 , p = 0.071 ) . each year in the united states , seasonal influenza accounts for > 200,000 hospitalizations and 41,000 deaths , and it is the seventh leading cause of death ( 10 ) . the effect of seasonal influenza in the tropics is less well studied . in thailand , influenza was detected in 11%12.5% of patients with community - acquired pneumonia and in 23% of outpatients with ili ( 11,12 ) . enhanced influenza surveillance in singapore in response to pandemic ( h1n1 ) 2009 yielded a high prevalence of seasonal influenza : 28.3% ( 85 of 300 ) among returning travelers and their contacts with respiratory symptoms , 14.4% ( 21 of 146 ) among hospitalized patients with suspected pneumonia , and 31.6% ( 30 of 95 ) among patients self - reporting to the ttsh emergency department with fever and respiratory symptoms but without a history of travel to affected countries . the risk of having seasonal influenza was lower among travelers returning from north america , a finding that was consistent with the timing of the peak local influenza season and the noninfluenza season in the northern hemisphere . of 21 patients with influenza - positive pcr results , only 5 had radiographic evidence of pneumonia despite having a pneumonia diagnosis based on an acute history of fever and cough . no patients , including those with positive test results , were treated with antiviral drugs . this finding , in addition to low influenza vaccine coverage in singapore , reflects the underappreciation of influenza by doctors in this country . of note , 67%73% of the patients with influenza - positive pcr results met the cdc ili criteria during the study period ; this finding may guide testing for seasonal influenza during peak influenza seasons in may june and december . its value in nonpeak seasons , however , requires further evaluation because influenza occurs year - round in the tropics ( 1 ) . temperature > 38c and either cough or sore throat ( 13 ) were the most specific screening criteria and had the best positive predictive value ; temperature of 37.5c and either cough , sore throat , or rhinorrhea were the most sensitive screening criteria and had the best negative predictive value for influenza ( table ) . our findings highlight a high prevalence of seasonal influenza during peak times in singapore ; the prevalence is comparable to that during typical influenza seasons in temperate countries in the southern hemisphere . this prevalence underscores the need for not neglecting seasonal influenza and for a more robust surveillance system to be in place for community and hospital monitoring in singapore . Output:	on april 25 , 2009 , singapore implemented strict containment measures for pandemic ( h1n1 ) 2009 with enhanced surveillance and hospital isolation . in the first month , seasonal influenza , predominantly virus subtype h3n2 , was diagnosed for 32% of patients with acute febrile respiratory illness . our findings underscore the high prevalence of seasonal influenza in singapore .
PubmedSumm118810	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: reticulate pigmentary dermatoses ( rpds ) are a group of uncommon disorders characterized by ephelid - like hyperpigmented macules coalescing to form reticular pattern , sometimes associated with scattered hypopigmented macules . most of the classifications of rpds rely on the sites of predilection , morphology , and arrangement of the lesions and the presence of hypopigmented lesions . common rpds include reticulate acropigmentation of dohi , reticulate acral pigmentation of kitamura [ rak ] ) , reticulate pigmented anomaly of the flexures ( dowling degos disease [ ddd ] ) , dyskeratosis congenita , naegeli franceschetti jadassohn syndrome , dermatopathia pigmentosa reticularis , confluent and reticulate papillomatosis of gougerot and carteaud , dyschromatosis universalis hereditaria , and others . ddd was described initially by dowling and freudenthal in 1938 and degos and ossipowski in 1954 . later in 1978 , wilson jones and grice portrayed ddd as demonstrating dusky dappled disfigurements and dark dot depressions and disclosing digitate downgrowths delving dermally . ddd and rak are both rare genodermatoses following autosomal dominant pattern of inheritance with variable penetrance that predominantly affect the flexures and the extremities , respectively . rebora and crovato in 1983 first suspected that ddd and rak were different phenotypic expressions of the same disease on the basis of their striking clinical and histopathological similarities . a 28-year - old indian male presented with multiple asymptomatic hyperpigmented macules over flexors , trunk , face , and extremities . the macules initially appeared on dorsum of both hands and feet during childhood and then on the extensor aspect of both forearms and legs . gradually freckle - like lesions appeared on axillae , groin , and forehead around the age of 22 years , which progressed to the upper back , flexural aspects of forearms , inner aspects of thighs , nape , and lateral aspects of the neck . interestingly , the interval between extensor and flexor involvement of the forearms was about 15 years ; the evolution of lesions was characteristically distal in first 15 years then gradually became proximal . the mucocutaneous examination revealed numerous symmetrical brownish hyperpigmented macules , 12 mm in size in axillae , groin , flexor and extensor aspects of both forearms , dorsae of hands and feet , both shins and inner aspects of thighs [ figure 1a and b ] . the lesions on the dorsae of hands , feet , and forearms were atrophic , whereas reticulate pattern was most pronounced on axillae , groins , and distal areas including proximal palms . few darkly pigmented comedo - like papules and few atrophic scars were noticeable over upper back and neck [ figure 1c ] . in addition , there were multiple palmar pits present with breaks in proximal palmer ridges . multiple pitted follicular scars were also noted on bilateral malar , mandibular , and perioral regions of face with no antecedent history of acne over same sites . ( c ) hyperpigmented macules over back and dark dot follicles histopathological examination of skin biopsy taken from nape of neck revealed circumscribed foci of epidermal proliferation in the form of elongated and confluent rete ridges , which displayed antler - like branching at places . the tips of rete pegs were hypermelanotic owing to concentrated pigment , which was also scattered within the papillary dermal macrophages [ figure 2a ] . biopsy taken from dorsal aspect of forearm revealed histopathology almost similar to that of biopsy taken from nape of neck except mild perivascular lymphocytic infiltrates [ figure 2b ] . these features are consistent with ddd . genetic study to identify hereditary pattern or possible mutations ( a ) elongated and confluent rete ridges with antler - like branching and dilated follicular infundibula 10 . ddd , also known as reticulate pigmented anomaly of the flexures is characterized by a dysfunctional mutation in the keratin-5 ( krt5 ) on chromosome 12q gene , leading to abnormal pilosebaceous epithelial proliferation . it classically manifests as an acquired progressive hyperpigmentation seen in females in their third or fourth decade . the sites involved are predominantly flexures ( axillae , groins , intergluteal and inframammary folds , anticubital fossa , neck ) , whereas trunk , arms , face , scalp , and genitalia are also involved in some cases . isolated involvement of the genitalia has also been reported . common additional findings include pitted follicular perioral and facial scars in patients with no previous history of acne and hyperkeratotic comedone - like follicular papules in the neck and/or back ( dark dot follicles ) . several recent reports have described an association of ddd with epidermal cysts , multiple keratoacanthomas , squamous cell carcinoma , abscess , hidradenitis suppurativa , seborrheic keratosis , and pilonidal cysts . our case may be unique as having an accessory tragus ; a condition apparently not previously reported . histopathological findings include acanthotic epidermis with irregular elongated rete ridges as filiform downgrowth in digitiform pattern ( antler - like branching ) , keratin cysts in the epidermis and dilated follicular infundibula . diffuse deposits of melanin are found in the basal layer and varying quantities of melanophages in the papillary dermis with no quantitative increase in the number of melanocytes . moderate hyperkeratosis , perivascular lymphohistiocytic infiltration within superficial dermis , and deep dermal fibrosis along with elongated rete ridges are additional features . on the other hand , rak usually manifests in first two decades of life and characterized by atrophic , slightly angulated freckle - like hyperpigmented macules in a symmetrical reticulate pattern on the acral skin ( dorsum of hands and feet ) , which may further progress up to the proximal aspects of limbs , neck , and occasionally face . earlier the rak cases were a majority from japan but now the cases have increasingly been reported from rest of the world . most of these have pointed toward autosomal dominant pattern of inheritance with variable penetrance , however , some intriguing patterns have been reported casting doubts about its pattern of transmission . histopathology is very similar to that of ddd , although epidermal atrophy , melanin incontinence , and perivascular lymphocytic infiltrate are more pronounced while lacking the antler - like pattern of the epithelial proliferation ; however , these features are no longer regarded as distinguishing features rak overlap in the literature and some authors even suggest the term dowling degos syndrome encompassing ddd , rak , haber syndrome , and acropigmentation of dohi . however , there are suggestions regarding the possibility of a chance association of multiple dermatoses , or atypical extensions of a single disease . the case we report also showed acral hyperpigmentation , palmar pits , and breaks in dermatoglyphics similar to that of rak and flexural macular lesions , comedo - like papules , and follicular pitted scars over the face , which were closely identical to that of ddd . interestingly , the patient developed features of rak in the first decade of life and of ddd in the third decade of life . there was no similar history of pigmentary lesions in the family , suggesting the sporadic nature of the disease . the other rpds such as haber 's syndrome and galli galli disease were excluded due to the absence of persistent facial erythema or rosacea - like features and absence of acantholysis histopathologically , respectively . other dyschromias such as dyschromatosis universalis hereditaria ( duh ) , and dyschromatosis symmetrica hereditaria ( dsh ) present as mottled hyperpigmentation and hypopigmented macules . the generalized variant of ddd has been described in the literature having hypopigmented or erythematous macules and papules but our case did not have such presentation . hypopigmented macules have been noted in ddd - overlap cases also from india previously . it may be emphasized that this case does not seem to be an incidental coexistence of ddd and rak as we noted the classical histopathological findings of ddd at a site of classical rak involvement . ( dorsal aspect of hands ) . moreover , atrophic macules were present even in the flexural aspects of forearms and ddd lesions , pointing to a true overlap . the authors concluded that the two might be different entities ; however , they have referred to only 6 and 11 cases of ddd and rak , respectively , where they mention three different gene defects localized in ddd and one in rak . the involvement of multiple genes in genetically studied cases of ddd could also point to the polygenetic nature of the disease and admits possible allowance of rak genes also in the same clinical spectrum . again , as the mentioned cases in that study had relatively distinct clinical features of either type of manifestation , the explanation of other reported overlap cases would need the presumed co - existence of the two very rare genetic diseases together that would be statistically very unlikely . in summary , our case connects to the hypothesis that overlaps between ddd and rak might be a single complex disease showing its different facets at different time points . Output:	dowling degos disease ( ddd ) and reticulate acropigmentation of kitamura ( rak ) are rare genodermatoses inherited as an autosomal dominant trait with variable penetrance . they are considered to be part of a spectrum of reticulate pigmentary dermatoses , characterized by the presence of hyperpigmented macules coalescing in a reticular fashion . the authors describe a 28-year - old male patient having hyperpigmented macules on the axillae , neck and face , reticulate acropigmentation of dorsum of the hands , forearms and feet , palmar pitting , and comedo - like lesions over back . the patient showed the unique clinical as well as histopathological overlap of both the rare diseases ( ddd and rak ) , substantiating the hypothesis that they represent two different features of a single entity with variable phenotypic expression .
PubmedSumm118811	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: there are several forms of transmissible spongiform encephalopathy ( tse ) diseases or prion diseases affecting humans and different species of farm and wild animals ( i.e. , sheep , cattle , and cervids ) . some of them have an apparently spontaneous occurrence ( i.e. , sporadic and genetic tses ; some forms of atypical bovine spongiform encephalopathy or scrapie ) , while others are linked to the consumption of prion - contaminated food as in the variant creutzfeldt - jakob disease ( cjd ) , feedstuff in bovine spongiform encephalopathy ( bse ) , or medical and surgical devices in iatrogenic cjd . transmission of variant cjd via blood transfusion and possibly plasma - derived factor viii from asymptomatic donors indicates that prion infectivity is present in blood months or years before clinical onset . thus , the occurrence of epidemics in farm animals and episodes of human cases linked to prion infection pose serious public health issues that are often difficult to solve . an eloquent example is given by the yet unexplained discrepancy between mortality ( 176 death from 1995 to june 2013 ) and estimated prevalence data ( 1 in 4,000 to 1 in 10,000 people ) of variant cjd in the british population . this incongruity is causing great concerns because healthy and infected donors who are not promptly identified might transmit disease by blood transfusion , surgical instruments , or plasma - derived products . the only validated surrogate marker of infection is the abnormally misfolded isoform of the cellular prion protein ( prp ) despite intensive but disappointing search for the identification of other disease - specific biomarkers in easily accessible tissues or body fluids [ 8 , 9 ] . misfolded prp ( prp ) accumulates in the cns and other tissues of infected hosts assuming different conformations that are related to the strain of prions . prp is easily detected by western blot or immunohistochemistry methods after removing the cellular isoform ( prp ) . most anti - prp antibodies , in fact , do not distinguish between prp and prp requiring the removal of the cellular isoform for achieving disease - specific signals . this is usually realised by pretreating samples with proteases ( usually proteinase k ) that partially digest prp but completely remove prp . the use of proteinase k ( pk ) , however , removes fractions of poorly aggregated misfolded prp that is usually present in blood and likely other body fluids decreasing the chance of detection . finally , it is still debated whether prp is unequivocally associated with prion infectivity as there are occasions in which prp is either not associated with infectivity or absent in infected hosts . despite these limits , prp remains the best available choice for confirming the diagnosis of prion diseases and for the identification of prion - associated infectivity in tissues and body fluids . moreover , the profile that assumes prp in western blot , reflecting different pathological conformations , is of great help for making a correct molecular diagnosis of sporadic cjd and for differentiating sporadic from variant cjd . in the last 15 years several methods have been developed for increasing the sensitivity of prp detection with the aim of finding a reliable assay for an early diagnosis of prion diseases in easily accessible tissues or body fluids . in 2001 , saborio and colleagues developed a novel protocol for the in vitro amplification of the misfolded prion protein based on the principle that disaggregated prp incubated in the presence of a large excess of prp produces novel prp . disaggregation of fibrils requires a sonication step , which can be repeated several times , in a cyclic process , to allow sensitive detection of the misfolded prp of the original seed . the protein - misfolding cyclic amplification ( pmca ) was originally developed using hamster brain homogenate and has since been shown to be an efficient method for the amplification of brain prp of other species including mouse , sheep , cattle , bank voles , cervids , and humans [ 1623 ] . in human samples , the amplification of prp is strongly influenced by the correct matching of methionine / valine in the 129 residue of prp , suggesting that this polymorphic site of the protein is important for the amplification of prp misfolding by the pmca assay [ 2426 ] . ten cycles of sonication are sufficient to increase the sensitivity of standard western blots from 612 picograms to 0.30.5 picograms of brain prp and , with an improved automated protocol which enables a substantial increase in the number of amplification cycles , up to femtogram levels . pmca is therefore a promising platform for prion diagnosis in body fluids ( blood , urine , and csf ) where the level of prp is estimated in the range of picograms per ml . the group led by soto reported the first successful identification of prp in blood ( buffy coat ) of scrapie affected hamsters with 89% sensitivity and 100% specificity and positive signals in 50% of samples taken in the preclinical stage of disease as early as 20 days after intraperitoneal 263k scrapie injection . the detection of prp in blood of preclinical scrapie - infected hamsters is consistent with data on infectivity detection in blood . since then , automated pmca revealed the presence of prp in plasma fractions , urine [ 2931 ] , and cerebral spinal fluid ( csf ) of scrapie - diseased hamsters with sensitivity ranging from 50 ( plasma ) to 100 percent ( csf ) ( table 1 ) . in the csf samples from scrapie - infected hamsters , pmca was performed by using a further improved protocol ( rprp - pmca ) in which prp was replaced by recombinant prp ( recprp ) , allowing a sensitivity greater than that observed with previous pmca protocols . other than in hamster models , prp was amplified from blood leukocytes of both naturally [ 20 , 34 ] and experimentally scrapie - infected sheep where prp bands were detected as early as 90 days postinoculation and correlated with infectivity titres . on leukocytes of naturally scrapie - infected sheep , prp was detected in all tested animals with 100% specificity by using an enhanced ( i.e. , addition of poly - a pmca ) protocol . attempts to detect prp in blood of other species such as cattle with bse and cervids with cwd produced negative or controversial results [ 34 , 37 , 58 ] . in patients with various forms of prion diseases , the detection of prp by pmca was not attempted ( or results were not published ) in sample of blood , blood derivatives , plasma , urine , or csf despite amplification of prp was successfully reported in human brain samples taken from both sporadic and variant cjds [ 16 , 2426 ] . finally , pmca amplification of prp in samples from body fluids , other than blood , taken from prion - infected hosts was successfully achieved in a variety of species and included saliva and urine in sheep with scrapie [ 36 , 36 ] ; saliva , urine , and csf in cervids with cwd [ 38 , 58 ] ; and csf and saliva in cattle with bse . a list of prion - infected body fluids analysed by pmca with the obtained sensitivity and specificity is shown in table 1 . in conclusion , pmca has certainly been a breakthrough for detection of minute amount of prp that are likely present in body fluids and therefore is a candidate method for developing sensitive tests for the diagnosis of prion diseases in animals and humans . moreover , the amplified product of pmca retains the prp signature of the original seed allowing the molecular diagnosis of cjd in humans and scrapie in sheep with important public health implications . in the last 10 years , pmca has frequently been modified by addition of poly - a or sulfated dextrans , by the use of recombinant prp instead of brain prp , or by coupling with sensitive immunoassays that have on one side improved the sensitivity of prp detection but , on the other hand , made the comparison of data produced by different laboratories difficult . pmca coamplifies infectivity together with prp [ 59 , 60 ] mimicking the disease - specific pathogenic event but requiring safety precautions in diagnostic laboratories . this finding , whether related to de novo formation of prp [ 20 , 60 , 61 ] or cross - contamination of samples , raised concern for the reliability of pmca in diagnostic applications . this inconvenience , however , is easily settled by using low pmca cycles and appropriate technical tips to avoid possible prion contamination . a spin - off of the pmca method was obtained by substituting sonication with automated tube shaking for the conversion of recprp substrates . the novel quacking induced conversion ( quic ) protocol enables the amplification of 1 femtogram of prp of scrapie hamster brain homogenate within one day , reducing the complexity and timing of misfolding amplification . hamster recprp promotes the conversion of brain misfolded proteins of other species such as sheep with scrapie and humans with sporadic and variant cjds , regardless of the primary sequence of the prp seed . some spontaneous pk - resistant fragments of less than 12 kd are occasionally observed in unseeded control samples , but they wane out by reducing the incubation time of the reaction . one of the most significant improvements of misfolding amplification methods was achieved when western blots were replaced by a real - time fluorescent colour reaction ( real - time quic ) [ 40 , 42 ] . this novel read - out system , based on a fluorescent amyloid - sensitive thioflavin dye ( tht ) , allowed the implementation of the whole quic procedure to a high - throughput 96-well format . the real - time quic ( rt - quic ) is an efficient quantitative method for the detection of minute amount of prp with estimates of the 50% seeding dose ( sd50 ) of hamster scrapie brain in the same order of magnitude of infectious doses ( ld50 ) . rt - quic protocol has been adapted to the detection of brain prp of other species such as cwd - infected deer , scrapie - infected sheep , and sporadic cjd patients by using species - specific recprp [ 40 , 42 , 64 ] . full - length human recprp and both truncated and full - length hamster recprps are efficient substrates for the amplification of prp in sporadic cjd brain irrespective of the 129 codon phenotypes [ 43 , 64 ] . a note of disappointment is that the efficacy of variant cjd brain in seeding rt - quic reaction is consistently lower than sporadic cjd samples . the presence of prp in the csf by the quic assay was initially revealed by atarashi and colleagues in 263k - scrapie infected hamsters and orr and colleagues in scrapie - infected sheep . in 2010 , wilham and colleagues revealed the presence of prp in the csf of 263k scrapie - infected hamsters by rt - quic and estimated a titre of about 10 sd50 per l . csf samples from control animals did not revealed any presence of prp indicating a high specificity of the assay . these encouraging results on the csf of scrapie - infected host promoted further studies in patients with various forms of prion diseases . a blinded experiment was initially performed on 30 csf samples of definite sporadic cjd patients provided by the australian national cjd registry and 155 controls ( 25 suspected cjd cases and 130 neurological controls ) achieving 87.5% specificity and 100% sensitivity . similarly , mcguire and colleagues screened csf samples from sporadic cjd patients provided by the national creutzfeldt - jakob disease research & surveillance unit , edinburgh , uk , including all three 129-codon genotype and obtaining 99% specificity and 94% sensitivity . in the same study , the specificity and sensitivity of the 14 - 3 - 3 protein , a surrogate marker currently used for the diagnosis of sporadic cjd , were 65% and 94% , respectively . an example of the rt - quic output in the csf of a sporadic cjd patient is given in figure 1 . finally , sano and colleagues reported that the rt - quic assay on the csf of patients with genetic prion diseases has 78% sensitivity in gss , 100% in ffi , 87% in e200k genetic cjd , and 100% in v203i genetic cjd , suggesting that the rt - quic assay for the detection of prp in the csf might become a valid method for improving the diagnosis of patients with a clinical suspicion of human prion disease . besides csf , the rt - quic assay revealed prp in nasal lavages from hamsters infected with the transmissible mink encephalopathy ( tme ) hyper strain and , by using immunoaffinity beads coupled with the conformational 15b3 anti- prp antibody ( enhanced quic ) , in plasma of scrapie - infected hamsters . the assay showed 100% sensitivity and specificity and was able to detect a positive signal long before the appearance of clinical signs of scrapie . finally , the application of 15b3-conjugated beads to the quic protocol and the use of a hamster - sheep chimeric recprp as substrate in the reaction increased the sensitivity ( up to attogram levels ) and the speed of detection ( 28 hrs ) of variant cjd brain misfolded proteins spiked into human blood . despite this good achievement there is still no report on the use of the enhanced quic assay in human blood . overall , rt - quic methodology is a powerful platform for the detection and large - scale screening of misfolded prp in both human and animals . up to attogram levels of misfolded prp can be detected and properly quantified within few hours by using high - throughput 96-well formats . the high levels of specificity obtained in a variety of tissues and species by using flexible recombinant substrates demonstrates the versatility of the novel method . it is of note that rt - quic pk - resistant products are reported to be noninfectious ( quoted by ) and therefore likely more secure in large - scale screening diagnostic procedures . the two disadvantages of this assay are the relatively poor performance in amplifying prp from variant cjd tissues and the failure to reproduce the original prp signature impeding the molecular diagnosis of sporadic cjd and the distinction between sporadic and variant cjds . the assay , originally developed by schmerr and colleagues and based on a competitive immunoassay with prp fluorescent peptides , was soon proven efficient for the detection of prp in blood of scrapie - infected sheep and elks with cwd . however , these results were not confirmed in other laboratories using blood samples from cjd - infected chimpanzees or sporadic , iatrogenic , genetic , and variant cjd patients [ 45 , 67 ] . it is therefore unlikely that this assay will be of any use for the diagnosis of human prion diseases . this assay consists in the immobilization of single prp aggregates on a capture antibody coated surface that are then visualized by the concomitant binding with two anti - prp fluorescent antibodies and a double - laser beam scanning system ( surface - fida ) . the method discriminates aggregated prp forms from monomeric prp without the use of the proteinase k ( pk ) digestion step and therefore recognizes both pk - resistant and pk - sensitive prp . surface - fida enabled the counting of bovine and hamster prp aggregates in brain homogenates and in bovine cerebrospinal fluid . prp aggregates were also blind - detected in blood of scrapie - infected sheep ( n = 15 ) with high specificity and sensitivity , although it remains unsettle whether the detection of prp aggregates correlates with infectivity . it is of note that spiking of blood plasma with prp from brain was unsuccessful suggesting that the properties of prp from brain are different from endogenous blood misfolded prp . terry and colleagues reported the detection of prp in 55% of blood mononuclear cells ( pbmc ) obtained from scrapie - affected sheep ( n = 80 ) and 71% of experimentally bse - affected sheep by a modified polyanionic ligand assay of the idexx herdcheck methodology . the assay resulted positive also in a subset of scrapie - infected sheep several months before the onset of clinical signs suggesting that prp can be detected in asymptomatic prion - infected hosts . however , the relatively low sensitivity observed in prion - infected sheep , the long timings of sample preparations , and the amount of blood volumes required for the purification of pbmc foretell that this assay would not be easily applicable to large - scale diagnostic scopes . the assay , based on the affinity that prp has for stainless steel particles [ 69 , 70 ] , was adapted for the detection of misfolded prp in blood of patients with various forms of cjds . the selective absorption of prp on the metal matrix concentrates misfolded protein up to the point that the signal can be detected by an elisa assay . because of the selectivity of the metal matrix in binding only misfolded prp , there is no need to pretreat samples with pk that likely removes a conspicuous fraction of prp in blood . this method was initially tested on human blood spiked with vcjd brain homogenate where misfolded particles in up to the 10 brain dilution were detected . subsequently , blood of variant and sporadic cjd patients was analysed on a blinded experiment including samples from patients with other neurological diseases and controls . about two - third of blood samples from variant cjd but none from sporadic cjd patients and neurological or nonneurological controls yield positive signals in both assays resulting in 100% specificity for variant cjd . in 2003 , paramithiotis and colleagues reported the manufacture of an antibody directed against prp epitopes that are exposed only upon protein misfolding and therefore specific to prp . this conformational anti - prp antibody was then used for the epitope - protection ( ep ) vcjd - screening assay , which was later implemented by amorfix . the high - throughput assay achieved 100% sensitivity and specificity on 1,000 blinded human plasma samples , which included samples that were spiked with variant cjd - infected and normal brains . in 2009 , the specificity of the method was ascertained on a large - scale screening initiated in france in over 20,000 human blood samples . results showed that on the first run 486 samples were positive ( 97.6% specificity ) , 20 of which were then confirmed positive on a second screening . subsequently , amorfix tested three variant cjd blood samples provided by the national institute for biological standards and control ( nibsc , uk ) that resulted negative . the sensitivity of the test was therefore further improved for the detection of 1 : 5,000,000 dilution of variant cjd - infected brain spiked into blood . however , despite this enhanced sensitivity , the test was still unable to detect prions in blood of variant cjd patients , and it was finally concluded that more research is required before the reevaluation of the assay . in 1998 , safar and colleagues developed an elisa - formatted , dissociation - enhanced time - resolved fluorescence detection system based on specific antibody binding to epitopes that are accessible in prp but that are unmasked only in denatured prp . this method does not require pk treatment and is able to recognize both sensitive and resistant pk misfolded proteins and different prp conformations . the assay , improved by incorporating a capture antibody , was able to discriminate prp signature in different molecular forms of sporadic cjds , iatrogenic cjds and genetic tses and detect up to a 10 dilution of prp from variant cjd brain used for spiking human normal plasma [ 54 , 73 ] . however , endogenous prp was undetectable in white blood cells of sporadic patients by cdi , but we are not aware of its use in variant cjd blood . this technique is based on a pyrene - labeled palindromic sequence of prion peptides that converts to -sheets in the presence of prp [ 56 , 74 ] . this process induces an excimeric signal from the conjugated pyrenes that propagates to other peptides with the final goal to amplify the prp signal . mpd assay detects prp in brain of 263k scrapie - infected hamsters during the preclinical and clinical stages of disease and in small volumes of plasma from prion - infected mice and sheep with sensitivity up to 1 infectious dose per ml . the same assay discriminated in blinded small - scale experiments control plasma from that of patients with sporadic cjd and squirrel monkeys with experimental cjd with 100% specificity and sensitivity . this technique is a modified elisa assay that recognizes only multimeric forms of prp without using any pretreatment with proteinases , which might remove prp forms likely present in body fluids . this assay uses the same principle previously described by pan and colleagues and is based on the use of two monoclonal antibodies that share overlapping epitopes . monomers ( prp ) are captured by an antibody attached to the surface of a plate and are not detected by the second antibody due to the absence of any exposed epitopes . on the other hand , multimers ( prp ) are easily recognized by the second antibody because they expose more copies of the same epitope . the assay was tested on plasma samples of nine scrapie - infected and nine control hamsters resulting in 100% specificity and sensitivity . this simple assay , however , requires validation in other laboratories and more basic work for determining whether the multimeric forms detected by the mds assay are related to infectivity . it is unquestionable that in the last 15 years there has been an outstanding progress in improving the detection of prp for developing sensitive and specific diagnostic assays . these sophisticated and highly sensitive methods successfully detect up to attogram levels of prp in body fluids of different species ( table 1 ) . a major breakthrough is the development of the rt - quic technology for the detection of prp in the csf of patients with sporadic [ 43 , 64 ] and genetic tses that as soon as is validated by other groups will change the diagnostic criteria of human prion diseases . endogenous prp has been identified in blood of scrapie - infected hamster by pmca [ 27 , 28 ] and rt - quic assays and of patients with variant cjd by the solid - state binding matrix assay . despite these successful observations , however , there are no published reports on the application of either pmca or enhanced rt - quic on blood samples of patients with any form of prion diseases suggesting that both assays still need substantial improvement before their use in the diagnostic setting . although the development of the rt - quic technology for the detection of prp in blood samples is more recent than pmca , an extra impediment of the rt - quic assay might come from the interference of blood molecules with the tht reading . on the other hand , the solid - state binding matrix assay might be a valid alternative for the development of a blood test for variant cjd , but the relative low sensitivity ( 71% ) and the finding that some control samples resulted positive in one of the two runs make the use of this assay a remote ambition . what remains elusive is the reproducible detection of endogenous prp in blood despite the successful identification of minute amounts of spiked brain prp into healthy blood . it becomes more and more evident that the properties of prp in brain are different from those in blood and that some components of blood both inhibit and interfere with prp detection causing false positive and negative results and compromising the reproducibility of the assay [ 46 , 51 , 76 ] . a clear example is given by the failure of the ep - vcjd assay that had excellent and reproducible performances on spiked blood but then completely failed to identify positive and negative human blood samples [ 5053 ] . these findings pose the question on whether the criteria delineated by the national institute for biological standards and control ( nibsc , uk ) for prion diagnostic assay validation in terms of satisfactory sensitivity and specificity on spiked blood and for the request of variant cjd blood samples are still relevant for defining the best condition of success of potential prion test in blood . we think that the principles for assay validation and accessibility to variant cjd blood samples should rather focus on reproducible and large scale blinded studies on blood taken from animal models of prion diseases , such as scrapie or bse in sheep followed by a large scale screening of healthy blood donors to ascertain a sufficient level of specificity . finally , our impression is that the research on prion detection in blood does not really need further sensitive assays but rather requires further work aiming to the identification of interfering blood components and understanding prion metabolism in blood . Output:	transmissible spongiform encephalopathy ( tse ) or prion diseases are fatal rare neurodegenerative disorders affecting man and animals and caused by a transmissible infectious agent . tse diseases are characterized by spongiform brain lesions with neuronal loss and the abnormal deposition in the cns , and to less extent in other tissues , of an insoluble and protease resistant form of the cellular prion protein ( prpc ) , named prptse . in man , tse diseases affect usually people over 60 years of age with no evident disease - associated risk factors . in some cases , however , tse diseases are unequivocally linked to infectious episodes related to the use of prion - contaminated medicines , medical devices , or meat products as in the variant creutzfeldt - jakob disease ( cjd ) . clinical signs occur months or years after infection , and during this silent period prptse , the only reliable marker of infection , is not easily measurable in blood or other accessible tissues or body fluids causing public health concerns . to overcome the limit of prptse detection , several highly sensitive assays have been developed , but attempts to apply these techniques to blood of infected hosts have been unsuccessful or not yet validated . an update on the latest advances for the detection of misfolded prion protein in body fluids is provided .
PubmedSumm118812	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: an approach that has met with some success has been the extension of criteria used to select donors , for example , including those older than 55 years , with a smoking history of more than 20 pack years , and an abnormal chest roentgenogram , a positive gram stain for sputum or bronchoalveolar lavage samples , or prolonged mechanical ventilation . despite this , people are dying while waiting for lung transplants , and there is thus an urgent need to increase the availability of donor lungs [ 13 ] . in many brain - dead donors , the arterial oxygen tension deteriorates to unacceptable values before organs can be harvested [ 4 , 5 ] . edematous lung tissue , due to excessive intravenous infusion in an attempt to maintain adequate donor circulation , may contribute to the deterioration of the gas exchange capacity . replacement of blood lost during the donor operation with crystalloid solutions will further hemodilute the donor and reduce the plasma colloid osmotic ( oncotic ) pressure [ 4 , 5 ] . due to their spongy structure , the lungs are especially vulnerable to edema under these conditions [ 4 , 6 ] . steen and colleagues have developed a new method for ex vivo lung evaluation [ 7 , 8 ] , which was used successfully for the first time in humans , when a lung from a non - heart - beating donor was transplanted at the department of cardiothoracic surgery at lund university hospital , sweden , in 2000 . the method can also be used for reconditioning of marginal and nonacceptable donor lungs , thus increasing the number of potential lungs available for transplantation . we have recently reported the results of the first six double lung transplantations performed with donor lungs , reconditioned ex vivo , that were rejected for transplantation by the scandiatransplant , eurotransplant , and uk transplant organizations . the six patients underwent double sequential lung transplantation with initially rejected donor lungs after reconditioning ex vivo . all six double lungs had an initial arterial oxygen pressure below 40 kpa during ventilation at 100% oxygen , and a positive end - expiratory pressure ( peep ) of 5 cm h2o before lung harvesting . the criteria for lungs chosen to undergo reconditioning were the same as for conventional donor lungs , except that a lower partial pressure of oxygen in arterial blood ( pao2 ) was accepted . to be accepted for transplantation after reconditioning , the pao2 at a fraction of inspired oxygen ( fio2 ) of 1.0 was required to be 50 kpa or higher , instead of the normal 40 kpa . one patient has since died from sepsis ( after 95 days ) , and one from rejection after nine months . four patients are alive and well two years after transplantation , without any signs of bronchiolitis obliterans syndrome [ 10 , 11 ] . in this paper we present our clinical experience from the first six patients in the world to receive such reconditioned lungs . figure 1(a ) shows the perfusion circuit , which consists of a hard - shell reservoir ( medtronic nederland , kerkrade , the netherlands ) , a centrifugal pump ( biomedicus , bio - console 550 ; electromedics inc . , grand rapids , mi ) , a membrane oxygenator with a built - in heat exchanger ( qadrox hmo 1011 ; jostra ag , germany ) , and a leukocyte / arterial filter ( lg 6 ; pall , newquay , cornwall , uk ) . a flow probe ( bio probe tx50 ; electromedics inc . ) , polytrode oxygen sensor ( po2 ; polystan , vrlse , denmark ) , and temperature sensors ( space labs medical inc . , redmond , wash usa ) are also included . a photograph of the setup is shown in figure 1(b ) . a 28-french venous cannula was placed with its tip in the main pulmonary artery ( figure 2 ) . a baby feeding catheter was placed in the pulmonary artery to measure the perfusion pressure . during reconditioning , , the pulmonary artery cannula was connected to the corresponding tube of the extracorporeal circuit , the air was removed , and the shunt of the circuit was clamped . the system was primed with 2 liters of steen solution ( vitrolife ab , lund , sweden ) , mixed with 2 units of abo - compatible erythrocyte concentrate , that had been irradiated , leukocyte filtered and washed , to a hematocrit of 15% . this solution is a buffered , extracellular solution with a composition designed to provide a colloid osmotic pressure allowing the physiological pressure and flow to be maintained without the development of pulmonary edema [ 5 , 7 , 8 , 10 , 12 ] . imipenem ( 0.5 g , tienam , merck sharp & dohme , sollentuna , sweden ) , insulin ( 20 iu , actrapid , novo nordisk , bagsvaerd , denmark ) , and heparin ( 10,000 iu , leo pharma , malm , sweden ) were added , and isotonic trometamol ( addex - tham , kabi , sweden ) was used to buffer the mixed solution to a temperature - adjusted ph of 7.4 [ 7 , 8 , 10 , 12 ] . figure 3 shows a flowchart of the first part of the reconditioning process , during which the lungs are not ventilated , and the perfusate blood is oxygenated . after removing the air from the pulmonary artery , slow perfusion ( perfusion pressure 20 mmhg ) the initial temperature of the perfusate was 25c , since the temperature of the lungs , after taking them out of the box with perfadex solution , and after connecting them to the ex vivo circuit , is approximately 15c , and the gradient between the lung temperature and the temperature of the perfusate is kept at approximately 10c . the temperature in the perfusate was gradually increased to 32c with a gradient of 10c . the flow was slowly increased , and the pulmonary pressure was kept at 20 mmhg . the left atrium pressure was maintained at 0 mmhg to prevent the development of edema . figure 4 shows a flowchart describing the second part of the reconditioning process , during which the lung is ventilated , and the perfusate blood is oxygenated . careful ventilation of the lungs was started ( 1 l / min ) when the temperature of the perfusate leaving the lungs had stabilized at 32c , as the ventilation of cold lungs may lead to lung membrane injury . the rate of ventilation was increased by one liter per minute for every degree increase in temperature of the perfusate leaving the lungs ( i.e. , the lung temperature ) up to 37c , at which normal ventilation ( 100 ml / kg / min ) was reached . the gases entering the oxygenator were mixed to obtain temperature - corrected perfusate gas values of pco2 of 4.55 kpa . the fio2 was maintained at 1.0 , and the respiratory frequency was gradually increased from 5 to 1520 per min . the perfusion flow was gradually increased and reached full flow ( 5 - 6 l / min ) at 37c . when the perfusate from the lung reached 37c , normal ventilation ( 100 mlkgmin ) was given . figure 5 shows a flowchart describing lung evaluation , during which the lung is fully ventilated and the perfusate blood is deoxygenated with a mixture containing 93% nitrogen and 7% co2 ( i.e. , the oxygenator is used to deoxygenate the perfusate ) , mimicking normal venous blood gas in the perfusate to the pulmonary artery , to be able to test the lung function . the peep was maintained at 5 cm h2o , except when it was temporarily increased to 8 cm h2o to eliminate atelectasis . the gases entering the oxygenator were mixed to obtain perfusate gas values of pco2 = 4.55 kpa . at this point , the rate of perfusion flow was maintained at 5 - 6 samples of blood were taken before and after passing through the lungs ( i.e. , venous and arterial blood samples ) to measure blood gases after 5 minutes ' exposure to fio2 of 0.21 , 0.5 , and , 1.0 . a deflation test was then performed , which consists of observing the lung after the endotracheal tube is suddenly disconnected from the ventilator . in a normal lung , the whole lung should be deflatied ( global atelectasis ) . if the deflation test was normal and the po2 at an fio2 of 1.0 was 50 kpa or higher , the lungs were accepted for transplantation . the duration of reconditioning and evaluation in the ex vivo circuit was between 1 and 2 hours . when reconditioning and evaluation of the lungs had been completed , and the surgeon had deemed them acceptable for transplantation according to the criteria described above , the lungs were cooled and preserved until the time of transplantation [ 13 , 14 ] . the temperature of the ingoing perfusate was reduced to 25c , and when the temperature had stabilized , perfusion was stopped . the pulmonary artery cannula and the trachea were clamped with the lungs in a semi - inflated state ( fio2 = 1.0 ) . the lungs were then immersed in the perfusate , to which a buffered perfadex solution was added . the extracorporeal circuit was then used to perfuse the solution through the box containing the immersed lungs , keeping the medium oxygenated and cooled at 8c . after ex vivo reconditioning , the initially rejected donor lungs were transplanted into the patients . double sequential lung transplantation was performed , with clam shell incision in four patients , and bilateral thoracotomy in the other two . three of the patients had been diagnosed with copd , one patient with cystic fibrosis ( cf ) , one with lung fibrosis , and one with 1-antitrypsin deficiency . the recipients had a median age of 54 years ( range 3564 y ) at the time of transplantation . the median height was 170 cm ( range 158180 cm ) , and the median weight 76 kg ( range 5594 kg ) . the donors had a median age of 59 years ( range 3463 y ) , a median height of 173 cm ( range 154182 cm ) , and a median weight of 77 kg ( range 4290 kg ) . the cause of death was cerebral bleeding in four of the donors , and two donors were resuscitated to spontaneous circulation after cardiac arrest . six of them had pao2 > 50 kpa at a fio2 of 1.0 after reconditioning ex vivo . the median pao2 of the donors of the six successfully reconditioned lungs was 21.1 kpa ( range 11.528.7 kpa ) at fio2 = 1.0 before harvesting . the corresponding values after ex vivo reconditioning were 68.7 kpa ( range from 51.6 to 79.5 ) . the median reconditioning time was 1 hour 29 minutes ( range , 1 hour 6 minutes to 2 hours 1 minute ) . the time from harvesting to connection to the ex vivo reconditioning circuit was 6.4 hours ( range 5.29.6 h ) , during which the lungs were stored in cold perfadex solution . the total median time from lung harvesting to transplantation was 16.4 hours ( range 10.617.5 h ) for the right lung and 18.0 hours ( range 12.621.5 h ) for the left lung . three of the six patients were reintubated after extubation , and one of these had to be reintubated a second time . the six patients were connected to a respirator for a median time of 191 hours ( range 252370 h ) . the patients remained in the intensive care unit for a median of 13 days ( range 499 d ) , and the median length of hospital stay was 52 days ( range 4599 d ) . one patient died due to sepsis , after 95 days , and one due to the rejection of the transplant after 9 months . the four patients surviving to the 12-month control showed increased 6-minute walking test values compared with the 3-month control , while the forced expiratory volume of air during 1 second increased in 3 and was the same in 1 patient . these four recipients are alive and well , without any signs of bronchiolitis obliterans syndrome , 24 months after the transplantation . in the present paper , we present our clinical experience from the first six patients undergoing double lung transplantation , with ex vivo reconditioned donor lungs initially considered unacceptable for transplantation . all the lungs had been rejected by transplantation centers , both national and international , due to low pao2 ( < 40 kpa ) after 5 minutes ' ventilation with 5 peep using 100% oxygen . if arrival time was before 11 pm , reconditioning and evaluation were performed followed by immediate double lung transplantation . lungs arriving after 11 pm were reconditioned and evaluated , and were then cooled , and transplantation was started at 8 am on the following day to avoid night - time surgery . we primed the system with steen solution and blood to a hematocrit of 15% , since all preclinical studies performed on animals by professor stig steen at our department have been carried out with this kind of priming . when performing the first clinical trials on humans , we believed it advisable to use the same priming as in the preclinical studies [ 7 , 8 ] . it may be possible to prime the machine in other ways with other solutions , or blood , but we have no such data . in patients where the total period of lung ischemia ( before reconditioning , reconditioning , evaluation , and after evaluation ) exceeded 17 - 18 hours , we found that even if the criteria for extubation regarding normal chest roentgenogram and excellent blood gases were fulfilled one to two days after surgery , they were not ready for extubation . if extubation was performed at this time , re - intubation and connection to a ventilator were often necessary a few hours later . we believe that half the fluid balance must be withdrawn from patients in this situation , and that one must wait at least two days after surgery , in addition to applying the conventional criteria for extubation , before extubation and disconnection from the ventilator are possible . we found that postoperative chest roentgenogram of the reconditioned lungs showed slightly increased vessel width and a tendency towards edema , which may indicate some kind of membrane injury in the lung parenchyma although the blood gas values were comparable to those in lungs not subjected to reconditioning prior to transplantation . double lung transplantation was carried out in all six patients , in order to be able to evaluate the reconditioning procedure . in single lung transplantation , blood may become oxygenated by the remaining native lung , making it difficult to evaluate the success of transplanting reconditioned lungs . all lung donors were free from pulmonary disease , and were not using any medication . the main reason for initial rejection of the lungs by the transplantation team was poor blood gas levels . poor oxygenation in brain - dead donors connected to a ventilator is often the result of pulmonary edema , atelectasis , lung emboli or aspiration . all these conditions are well - known causes of a rapid decrease in oxygenation capacity . with the ex vivo reconditioning and evaluation technique described here , it was also possible to carry out careful suction in the bronchus to minimize the effects of aspiration . using the technique described in the present paper , we were able to treat pulmonary edema and atelectasis in the donor lungs and reevaluate their suitability for transplantation . the technique had not previously been used clinically on humans , and we increased the limit for acceptance for transplantation from the golden standard of po2 > 40 kpa to > 50 kpa after 5 minutes of ventilation with 5 peep . there was no evidence for this increased level , but it was adopted to increase the safety margin . based on our findings and experience , we would like to make the following two important recommendations to other cardiothoracic transplantation centers considering such an ex vivo lung reconditioning process to increase the number of donor lungs available for transplantation . perform the transplantation immediately , or as soon as possible , after reconditioning and evaluation to limit the duration of ischemia . we encourage a careful attitude towards increasing ischemic time to an already marginal donor lung . at the same time , it would be an advantage , to both the surgeon and the patient , if night - time surgery could be avoided . promising results have been obtained from experimental studies in pigs , where it was shown that the lungs and their vascular function could be safely preserved for up to 24 h , that the gas exchange system of the lungs can tolerate 1 h of warm ischemia after circulatory arrest without significant loss of functional capacity , and that the pulmonary artery can withstand warm ischemia for 3 h after death without impairment of endothelium - dependent relaxation or vascular smooth - muscle function . furthermore , it has been demonstrated that simple topical cooling of nonventilated lungs provides excellent preservation conditions for 1224 h [ 13 , 14 ] . however , long - term followup of a larger patient cohort is necessary before this method can become a clinical routine . do not extubate and disconnect the patient from the ventilator during the first 24 hours after surgery , even if the chest x - ray appears normal , and the blood gases are excellent , that is , the criteria for extubation are fulfilled . we strongly recommend waiting 2 - 3 days , and ensuring that at least half of the fluid balance is withdrawn before extubation is performed . in normal clinical lung transplantation , poor posttransplantation function remains a major problem , with significantly impaired function in 10% to 20% of cases . it is , therefore , of the utmost importance to identify these lungs in advance , especially when using marginal donors . this method may be useful in the evaluation of marginal donor lungs as well as lungs from non - heart - beating donors . furthermore , this method allows the time between harvest and transplantation to be increased , thereby allowing better planning for transplantation . among other things , this will allow for the optimization of donor - recipient matching , for example , with hla ( human leukocyte antigen ) . we believe that this ex vivo reconditioning and evaluation model provides a valuable addition to the armamentarium for finding acceptable lungs in a donor population with inferior pao2 values . however , as always , donor selection comes down to sound clinical judgment based on all the available data . Output:	a major problem in clinical lung transplantation is the shortage of donor lungs . only about 20% of donor lungs are accepted for transplantation . we have recently reported the results of the first six double lung transplantations performed with donor lungs reconditioned ex vivo that had been deemed unsuitable for transplantation by the scandiatransplant , eurotransplant , and uk transplant organizations because the arterial oxygen pressure was less than 40 kpa . the three - month survival of patients undergoing transplant with these lungs was 100% . one patient died due to sepsis after 95 days , and one due to rejection after 9 months . four recipients are still alive and well 24 months after transplantation , with no signs of bronchiolitis obliterans syndrome . the donor lungs were reconditioned ex vivo in an extracorporeal membrane oxygenation circuit using steen solution mixed with erythrocytes , to dehydrate edematous lung tissue . functional evaluation was performed with deoxygenated perfusate at different inspired fractions of oxygen . the arterial oxygen pressure was significantly improved in this model . this ex vivo evaluation model is thus a valuable addition to the armamentarium in increasing the number of acceptable lungs in a donor population with inferior arterial oxygen pressure values , thereby , increasing the lung donor pool for transplantation . in the following paper we present our clinical experience from the first six patients in the world . we also present the technique we used in detail with flowchart .
PubmedSumm118813	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: arterial blood gas ( abg ) analysis is regarded as gold standard for assessing patient 's oxidation , ventilation , and acid - base balance status . however , compared to venous blood sampling , arterial blood sampling needs specially trained personnel and comes with a higher risk of complications , e.g. , pain , trauma , bleeding , hematoma , thrombosis with distal ischemia , aneurism formation , hemorrhage , and infection . reporting strong associations between venous and arterial blood gases , several studies have suggested taking venous instead of arterial blood samples to measure patient 's blood gases and acid - base balance . the aim of this study was an in - depth analysis and evaluation of associations between venous and arterial blood ph and partial pressure of carbon dioxide ( pco2 ) in post - brain surgery patients receiving mechanical ventilation . the participants were selected within two months with the inclusion criteria as follow : all patients were admitted to shariati educational hospital , were over 18 and selected while they were on mechanical ventilation at intensive care unit ( icu ) following a brain surgery . patients were excluded if any of the following conditions existed : a positive allen test , hypothermia ( temperature < 36c ) , hyperthermia ( temperature > 38.5c ) , hypotension ( systolic blood pressure < 90 mm hg ) , hypertension ( systolic blood pressure > 140 mm hg , or diastolic blood pressure > 90 mm hg , or treated ) , anemia ( hb < 10 mg / dl ) , or uncontrolled metabolic disease . of 60 patients , 9 were excluded ( 4 due to hypothermia , 2 due to anemia , 1 due to hypotension , 1 due to hypertension , and 1 due to acute tubular necrosis ) . arterial and venous blood samples were taken simultaneously with heparinated syringes from radial artery of the wrist and elbow vein . after informed consent was obtained and allen test was conducted with negative result , 0.5 - 1.0 cc of the blood samples were taken to measure abg and vbg levels . samples were analyzed in a blood gas electrolyte analyzer ( avl compact 2 ) . as suggested by bland and atman and generally accepted by other researchers , the agreement between arterial and venous values was measured using plots of mean of paired arterial and venous values against their differences . pearson 's correlation coefficient ( r ) was also used to measure the strength of association between arterial and venous ph and pco2 . these methods are generally accepted for evaluating the agreement of two methods of clinical measurements irrespective of the distribution of variables and residuals . in the present study , the goodness of fit of the models and the distribution of residuals was graphically evaluated by checking the distribution of regression residuals against arterial values . based on central limit theorem , normality was assumed fulfilled when regression equations and pearson correlation coefficients were calculated . in total , 51 patients with simultaneous arterial and venous blood samples participated in this study . mean patient age was 59.2 years ( sd = 15.1 , range = 38 - 91 ) . mean values for pulse rate and respiratory rate were 83 bpm ( sd = 23 ) and 17 breaths per minute ( sd = 8) , respectively . venous and arterial pco2 and ph statistics are presented in table 1 . as can be seen in table 1 , a wide range and non - zero ( biased ) average of differences between venous and arterial values for the above indices are observed ( mean of differences are 7.21 mm hg , p < 0.001 and -0.03 mm hg for pco2 and ph , respectively , p < 0.001 ) . venous and arterial blood gas ph and pco2 values the associations of venous and arterial ph and pco2 values are shown graphically and mathematically in figures 1 and 2 . the figures show lines of unity ( intercept = 0 , slope = 1 ; dotted lines ) , regression line ( solid line ) , and their regression equations . figures 3 and 4 represent the distribution of the residuals . precision and accuracy of venous values representing arterial ph and pco2 levels are illustrated by bland - altman plots [ figures 5 and 6 ] . the dotted lines show theoretically unbiased predictions , and the solid lines are regression lines fitted to the average and difference of arterial and venous measures to check whether differences between two measures are constant as the average of venous and arterial values increases . a horizontal regression line represents homogeneity of the differences between arterial and venous values throughout predictor variation . figure 1 shows a strong correlation between arterial and venous ph ( r= 0.64 , p < 0.001 ) . however , the distribution of the residuals for the regression equation seems to be heterogeneous , as the correlation becomes weaker as the arterial values ( dependent variable ) increase [ figure 2 ] . moreover , the significant association between residuals and arterial values ( p < 0.001 ) suggests that a linear regression model is sub - optimal for prediction of arterial ph across the observed range of measurements . differences between arterial and venous values against their averages suggest that venous values are predominantly less than arterial levels and the differences get closer to null as the average values increase [ figure 3 ] . dotted line represents line of unity ) correlation between arterial and venous blood pco2 ( solid line represents regression line . dotted line represents line of unity ) arterial ph vs residuals of regression of abg on vbg for ph although , compared to ph , the correlation coefficient for the venous versus arterial blood pco2 values is smaller , it is also highly significant ( r= 0.31 , p < 0.001 ) [ figure 4 ] . as shown in figure 5 , the distribution of the residuals of the regression model for venous and arterial pco2 is heterogeneous . the significant association between residuals and arterial values ( p < 0.001 ) suggests that a linear regression model is sub - optimal for prediction of arterial pco2 across the observed range of measurements . the difference between venous and arterial pco2 values is predominantly positive , and increases as average arterial and venous values increase [ figure 6 ] . arterial vs residuals of regression of abg on vbg for pco2 bland - altman bias plots of venous ( vbg ) and arterial ( abg ) blood gas values for ph bland - altman bias plots of venous ( vbg ) and arterial ( abg ) blood gas values for pco2 arterial blood gas and acid base analysis are essential parts of medical care in icu . however , arterial blood sampling is invasive and technically complicated , whereas venous blood sampling is easier and safer to obtain . strong associations of arterial and venous blood gases and acid - base balance have been reported previously ; all assumed sufficiency of a linear model . this study further evaluated the ability of linear models in predicting venous ph and pco2 from arterial ph and pco2 . consistent with other researchers , we found a significant correlation coefficient between arterial and venous blood ph ( r = 0.64 , p < 0.001 ) . however , the precision of prediction is not consistent and deteriorates as arterial blood ph increases . the distribution of residuals also indicates a significant variation in the prediction of arterial ph values from venous blood samples . the findings suggest that simple linear models may not represent the association between arterial and venous ph and pco2 values appropriately . accordingly , using the generally accepted methods , venous blood ph value may not be a reliable proxy for arterial ph . with respect to pco2 , a weaker but still highly significant correlation between venous and arterial measurements was observed ( r = 0.31 , p < 0.001 ) . compared to acid - base values , the correlation between venous and arterial pco2 values is more consistent across the range of measurements . however , the distribution of residuals indicates considerable variation in the precision of predicted arterial pco2 from venous blood samples . while several studies have suggested that the substitution of arterial with venous blood pco2 values is of clinically utility , our findings as some others suggested otherwise . debate over feasibility of substitution of arterial ph and pco2 with their equivalent venous measurements is ongoing . the difference between studies in methods , analyzer machines , and types of patients may explain the contradictions in the studies results . although the results of this study on the significant correlation between venous and arterial pco2 and ph are compatible with existing literature , our findings questioned the suitability of a simple linear regression and the precision and accuracy of arterial values estimated by venous values across all ranges of measurements . multivariate or non - linear regression models could be considered as alternative methods in similar situations . our conclusion is to be considered preliminary due to limited generalisability of the study results . our conclusion is to be considered preliminary due to limited generalisability of the study results . he is the director of research of medical school at islamic azad university branch najafabad . e - mail : [email protected] bahareh ghahramanpoori received her m.d degree from azad najafabad university , najafabad , iran in 2008 . she has been employed in namazi hospital neurosurgery icu and trauma ward as physician for three years . since 2011 she works as a family physician for shiraz university of medical sciences , shiraz , iran . e - mail : [email protected] mohammad fararouei received his b.sc . degree in public health in 1990 from the school of health of shahid beheshti university of medical sciences , tehran , iran . phd degrees in epidemiology in 1995 from shiraz university of medical sciences , shiraz , iran and in 2008 from imperial college london , london , uk respectively . since 2008 , he has been with the school health at yasuj university of medical sciences , yasuj , iran where he is currently an assistant professor . Output:	substitution of arterial with venous blood samples to estimate blood gas status is highly preferable due to practical and safety concerns . numerous studies support the substitution of arterial by venous blood samples , reporting strong correlations between arterial and venous values . this study further investigated the predictive ability of venous blood samples for arterial acid - base balance ( ph ) and pressure of carbon dioxide ( pco2 ) . participants were 51 post - brain surgery patients receiving mechanical ventilation , who had blood samples taken simultaneously from radial artery of the wrist and elbow vein . results showed significant associations between arterial and venous ph and pco2 . however , the variation of regression residuals was not homogenous , and the regression line did not fit properly to the data , indicating that simple linear regression is sub - optimal for prediction of arterial ph and pco2 by venous blood sample . although highly significant correlations were found between arterial and venous blood ph and pco2 , the results did not support the reliability of prediction of arterial blood ph and pco2 by venous blood samples across a range of concentrations .
PubmedSumm118814	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: growth failure in utero increases risk for both neurodevelopmental delays and the elements of the metabolic syndrome ( insulin resistance , coronary heart disease and hypertension ) later in life [ 2 , 3 ] . paradoxically , continued growth failure limits impact of prenatal undernutrition on subsequent metabolic syndrome [ 46 ] , but growth failure adds to the neurodevelopmental burden [ 79 ] . thus absence of a prenatal : postnatal mismatch in nutrition diminishes risk for the health consequences and increases risk for developmental delay later in life in populations at risk for undernutrition [ 49 ] . there have been dramatic increases in prevalence of pediatric obesity in the united states over the last 30 years [ 1012 ] . school age children in impoverished african and hispanic ancestry families are just as likely to be overweight or obese , defined as body mass index ( bmi ) above the 85th percentile for age and gender , as they are to be lean [ 11 , 13 ] . the objectives for the present study are to determine what relationship , if any , ( 1 ) birth weight and ( 2 ) weight gain in the first six months of life , divided as first 3 months and second 3 months , have with bmi of children at 4 to 6 years of age . variables available for study include birth weight , weights of infants at return visits to clinic in the first 6 months of life , and measures of weight and height with calculated bmi at 4 to 6 years of age . the subjects were a convenience sample cohort of 154 children attending the resident continuity clinic at suite d in brooklyn , new york . consecutive charts were reviewed retrospectively for the 154 children who had presented themselves for the set of immunizations commonly received at four years of age . the suite d clinic serves an inner - city population in which approximately 31% of the children live in families with incomes below the poverty level . the racial distribution of suite d families is 81% african ( black ) , 10% hispanic , 5% european ( white not hispanic ) , 1.5% asian , and 2.5% other classifications ; however , the racial designations commonly used by the census bureau are not explanatory variables for this population , which is of predominantly afro - caribbean ancestry . all children were born at the state university of new york - downstate medical center . multiple imputation of missing data was used to avoid low power and bias associated with complete set analyses . sas ( sas institute , cary , nc ) proc mi was used to impute 25 values from a normal distribution for each missing bodyweight value . data points were added for all children over the subsequent 12 months , permitting assessment of bmi for children 4 to 6 years of age . weight to the closest 10 grams and length at birth to 6 months of age and height at 4 to 6 years of age to the closest 0.5 cm were recorded with date of measurement using techniques described by jelliffe . mixed linear models were constructed with bmi in years 4 to 6 as the dependent variable . gender was introduced as a fixed factor as was age in years as use of a shorter age distribution would have increased the number of parameters in this complex model to the extent of unmanageability . following the postpartum age division made by eid , birth weight and weight changes in the first 3 months and in the second 3 months of life software used was sas release 9.1.3 ( sas institute , cary , nc ) . the suite d clinic serves a predominately afro - caribbean population that is representative of the community at large . families served receive broad access , which is made available through public programs including medicaid and state child health insurance . these programs require that incomes be below 2.6 times the united states poverty level of $ 22,500 per year for a family of 4 people . of note , children in families that do not have documentation of legal status in the united states are eligible for these child insurance programs . approval for the study was received from the institutional review board of suny - downstate medical center . of the total of 699 observations of bmi during years 4 to 6 of life for the 154 patients , there were 366 observations belonging to 76 patients with weight recorded at both birth and 3 months ; 280 observations belonging to 60 patients had weight recorded at birth , 3 and 6 months . while girls were more likely to become overweight , gender was not a statistically significant predictor of bmi in years 4 to 6 of life ( f = 3.78 , p = 0.058 ) . neither birth weight quartile ( f = 1.62 , p = 0.197 ) nor weight gain quartile from birth to 3 months of age ( f = 0.26 , p = 0.853 ) was a significant predictor of bmi in years 4 to 6 of life . weight change quartile during months 4 to 6 of life , however , was a significant predictor of subsequent bmi at 4 to 6 years of life ( f = 3.47 , p = 0.023 ) . controlling for the other terms in the model , estimated log bmi ( mean / standard error ) in years 4 to 6 of life by weight gain category in months 4 to 6 is shown in table 1 . the means of the two lower quartiles differed significantly from those of the two upper quartiles . the data presented herein show significant correlation between weight gain from four to six months of age and bmi at ages four to six years . these findings remained significant when adjusted for birth weight , age of measurement , and gender . by contrast , using the same data set , negligible and nonsignificant differences were found when comparing weight gain from birth to three months of age and bmi at ages four to six years ; noneffect for weight gain measures below three months of age shown by f statistics were all less than 1.0 . prenatal experiences with nutritional deprivation have a profound impact on postnatal responses to abundance ( metabolic syndrome ) [ 16 ] or continued malnutrition ( neurodevelopmental delay ) [ 79 ] . weight faltering , as described by emond et al . in their review of the impact of infant growth on subsequent neurodevelopmental delay , is a common occurrence in this community . the data presented herein provides evidence that weight gain in the first three months may not have the impact on subsequent overweight or obesity similar to that found for gain in the full first six months has . the data suggest that weight gain in the second three months following birth , however , is the significant predictor of body mass index in years 4 to 6 in our population . the weight gain from birth to 3 months of age , however , did not contribute significantly to the prediction . findings for the full sample of 154 children , analyzed using techniques provided for disrupted series , remained robust when adjusted for birth weight , age of measurement , and gender ( f test less than 1 ) . data from the present study showing weight gain for the first six months , considered in their entirety , are consistent with those of eid , and of dennison et al . who observed that weight gain from birth to six months of life was associated with increased risk of being overweight at 4 years of age ; these findings were independently of potential confounders . our data for weight gain in the first three months are , however , inconsistent with those provided by stettler et al . in a multicenter study of 19,497 infants with a wide variety of social and ethnic backgrounds . these authors used a cut - off of 4 months of age finding that [ a ] pattern of rapid weight gain during the first 4 months of life was associated with an increased risk of overweight status at age 7 years . a microanalysis of their data , taken from a subset of 300 african american children from inner - city philadelphia , replicated the correlation of rapid gain to 4 months of age and subsequent finding of overweight . limitations of the present study include using bmi as an outcome , as this measure does not necessarily imply obesity [ 12 , 22 , 23 ] . while children with bmi level at or above the 85th percentile are said to be overweight or at risk for obesity , the distribution of fat and muscle accumulation varies by age , ethnicity , timing of the adiposity ( or bmi ) rebound , birth weight , and rate of weight gain [ 12 , 24 , 25 ] . thus , accurate measures of fat deposition rather than lean muscle mass can not be determined from a retrospective analysis of weight and height measures . while data provided by hediger et al . suggest that the principle component of excessive weight gain in childhood is body fat , wells et al . provide data suggesting that effects of birth weight and rate of weight gain may influence lean and fat components of bmi differently in differing populations . an additional limitation is that our data are derived from measures of a population with the unique characteristics of central brooklyn , ny , an inner - city borough of new york city with 2.3 million residents . there are 315,000 people in suny - downstate 's primary service area , the venue for the present study . the genetic , social , and economic influences on families attending suite d are neither representative of the population of brooklyn as a whole nor of other inner - city communities in the united states such as the one described by stettler et al . . the families live at or just above the poverty level which substantially influences parenting practices , food purchase and consumption patterns , and increases risk for obesity [ 12 , 19 , 2630 ] . as gopalan points out differences . between communities can result in important differences with nutritional status ( especially of children ) between households , and between communities with nearly similar overall levels of dietary inadequacy " . other variables likely to affect propensity for weight gain would include both paternal and maternal obesity , surgery to correct obesity , parental education , and food insecurity in the family . the patient records reviewed to develop the data set for the current study do not have data to show differences between the population surveyed and others . use of data from the present study of a special sample in other populations and circumstances would require an in - depth analyses of antecedents , behaviors , and outcomes . a larger population would permit a shorter distribution of ages for outcome measures ; however , observations drawn from macrosocial studies should not deter investigation of specific populations with unique characteristics , nor should data accumulated in microstudies be applied generally without careful investigation of applicability . the data presented herein suggest that , for this specific population , weight gain can be promoted when it is most essential . all require careful investigation of the variables affecting weight gain in the first months of life . Output:	background . while rapid early weight gain are common in children who become obese later in life , so is growth faltering in the first 3 months of life . objective . we seek to determine what relationship weight gain in the first six months of age , separated into two 3-month periods , have with the bmi of children ages 4 to 6 years in an inner - city community . subjects . a convenience sample cohort of 154 children attending an inner - city clinic . methods . consecutive charts were reviewed retrospectively . age , gender , birth weight and weight change in the first and second 3 months of life were introduced as fixed factors using mixed linear models with bmi in years 4 to 6 as the dependent variable . results . weight change quartile in the first 3 months of life did not predict of bmi in years 4 to 6 ; however , weight changes quartiles during months 4 to 6 were significant predictors for subsequent overweight . conclusion . the data presented herein suggest that , for this specific population , weight gain can be promoted when it is most essential . it is necessary , however , to identify intermediary variables that could affect outcomes in this and other communities .
PubmedSumm118815	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: interferon beta ( ifnb ) immunomodulatory treatment in patients with relapsing - remitting multiple sclerosis ( rrms ) demonstrates the average reduction of the relapse rate by 30% , with considerable variations between patients . the effect on radiological activity of the disease was confirmed in phase iii clinical trials with interferons and glatiramer acetate preparations , where the 30% reduction in the number of new t2 lesions on magnetic resonance imaging ( mri ) was demonstrated as compared with the placebo - treated patients . one of the factors that determine an incomplete response to treatment could be the production of antibodies against these drugs in patients . therefore , it is recommended to assess the patient 's response to treatment after the first year of immunomodulation . patients can produce binding antibodies ( babs ) and neutralizing antibodies ( nabs ) against ifnb . although only nabs are able to neutralize ifnb function in bioassays , while babs represent all antibodies binding to the interferon molecule , it has been shown that babs decrease ifnb bioavailability independently of nabs . moreover , these antibodies are capable of forming cross - reactions with other interferons . all of the known mechanisms of ifnb immunomodulatory activity are based on its binding to a target receptor on the surface of immune cells . this process activates the intracellular tyrosine kinase cascade leading to transcription of a number of genes . it may be disrupted when the antibodies change the normal structure of the protein , in this case interferon , which is necessary for the interaction with its receptor . according to gneiss et al , patients who present with nabs during ifn treatment will not benefit from continuous therapy with any subcutaneous ifnb preparation . it is generally not recommended to apply the drug of the same group ( i.e. interferon ) in case when neutralizing antibodies presence is confirmed ; however , these recommendations are based on single studies only . few studies were conducted with regard to cross - reactivity between 2 different interferon preparations used in clinical practice . in our pilot study , we wanted to determine whether any immunological cross - reactions occur between interferons in a full spectrum of ifn formulations that are commercially available . fourty - nine rrms patients receiving ifnb 1a in a dose of 44 g 3 times a week for 2 years were included in this prospective observational pilot study . patients were enrolled from the out - patient ms clinic by the department of neurology and cerebrovascular disorders , poznan university of medical sciences . written informed consent to participation in the study the study protocol was approved by the internal review board at the poznan university of medical sciences . the study group consisted of 35 women ( 71.4% ) and 14 men ( 28.6% ) , with the mean age of 32.8 7.9 years and the mean disease duration of 7.5 4.2 years . the median expanded disability status scale ( edss ) score in the group was 1.0 , with a minimum of 0.0 and a maximum of 4.0 , and the mean total number of relapses was 3 ( min 1 , max 4 ) . all patients enrolled in the study met the diagnostic criteria for ms according to polman et al . serum samples were tested for the presence of antibodies binding ifnb ( babs ) in patients after 2 years of immunomodulatory treatment and the same assay was repeated after 1 year from interferon treatment cessation . the reaction of patients serum with commercially available formulations of ifnb-1a ( rebif and avonex ) and beta-1b ( betaferon ) was tested to reveal interferon binding antibodies . babs assessment was carried out in the department of neurochemistry and neuropathology , chair of neurology , poznan university of medical sciences poznan , poland , by means of home - made indirect elisa . 96-well elisa plates ( nunc , roskilde , denmark ) were coated with interferon beta preparations diluted in 0.05 m sodium bicarbonate ( ph = 9.6 ) to obtain final concentration of 1 g / ml per well . the plates were incubated for 12 hours at room temperature for antigen immobilization . after careful washes with phosphate - buffered salt ( pbs ) with 0.05% ( vol / vol ) tween 20 , the nonspecific binding sites were blocked with 1% bovine serum albumin solution in pbs-0.05% tween 20 . washing with pbs-0.05% tween 20 was followed by addition of blind samples ( pbs added instead of serum ) , rat serum serving as negative control , goat anti - human interferon antibodies ( sigma - aldrich ) as the standard ( in decreasing dilutions 1:20 , 1:50 , 1:100 , 1:200 and 1 : 400 ) ; sera from treatment - naive ms patients and study group sera tested at a dilution of 1:100 , respectively . room temperature incubation , pbs-0.05% tween 20 washes were followed by the addition of secondary antibodies ( goat ant - rabbit igg , sigma - aldrich , or rabbit anti - human igg conjugated with alkaline phosphatase , sigma - aldrich , respectively ) . p - nitrophenyl phosphate was used as the substrate ( sigma - aldrich ) and the reaction was stopped with 1 m hcl . the absorbance was measured with the elisa reader elx800 ( bio - tek ) at the wavelength of 405 nm . the above - mentioned procedure was carried out consecutively for plates coated with all the tested interferon preparations rebif , betaferon , and avonex . the results were expressed as the optical density ( o.d . ) , arbitrary units au / ml ( au arbitrary units ) , and reciprocal serum dilution ( rsd ) . arbitrary units were calculated according to the formula : ( 10 absorbance of tested sample)/absorbance of the cut - off values . the cut - off was established as 95th percentile of absorbance for each series of tested samples ( with rebif , betaferon , avonex as antigens ) performed in immunomodulatory treatment naive ms patients . cut - off values in tests using rebif as the antigen were 0.180 , for avonex0.208 and betaferon0.074 . reciprocal serum dilution was calculated according to the formula : [ 1 : x ] , where x is dilution of standard antibodies obtained from the fitting of standard curve . the standard curve fitting was based on the calculation of log log regression between absorbance and reciprocal standard dilution ( r = 0.9777 ) . then , the absorbances of tested samples were substituted to the regression formula and reciprocal serum dilutions were calculated . fourty - nine rrms patients receiving ifnb 1a in a dose of 44 g 3 times a week for 2 years were included in this prospective observational pilot study . patients were enrolled from the out - patient ms clinic by the department of neurology and cerebrovascular disorders , poznan university of medical sciences . written informed consent to participation in the study the study protocol was approved by the internal review board at the poznan university of medical sciences . the study group consisted of 35 women ( 71.4% ) and 14 men ( 28.6% ) , with the mean age of 32.8 7.9 years and the mean disease duration of 7.5 4.2 years . the median expanded disability status scale ( edss ) score in the group was 1.0 , with a minimum of 0.0 and a maximum of 4.0 , and the mean total number of relapses was 3 ( min 1 , max 4 ) . all patients enrolled in the study met the diagnostic criteria for ms according to polman et al . serum samples were tested for the presence of antibodies binding ifnb ( babs ) in patients after 2 years of immunomodulatory treatment and the same assay was repeated after 1 year from interferon treatment cessation . the reaction of patients serum with commercially available formulations of ifnb-1a ( rebif and avonex ) and beta-1b ( betaferon ) was tested to reveal interferon binding antibodies . babs assessment was carried out in the department of neurochemistry and neuropathology , chair of neurology , poznan university of medical sciences poznan , poland , by means of home - made indirect elisa . 96-well elisa plates ( nunc , roskilde , denmark ) were coated with interferon beta preparations diluted in 0.05 m sodium bicarbonate ( ph = 9.6 ) to obtain final concentration of 1 g / ml per well . after careful washes with phosphate - buffered salt ( pbs ) with 0.05% ( vol / vol ) tween 20 , the nonspecific binding sites were blocked with 1% bovine serum albumin solution in pbs-0.05% tween 20 . washing with pbs-0.05% tween 20 was followed by addition of blind samples ( pbs added instead of serum ) , rat serum serving as negative control , goat anti - human interferon antibodies ( sigma - aldrich ) as the standard ( in decreasing dilutions 1:20 , 1:50 , 1:100 , 1:200 and 1 : 400 ) ; sera from treatment - naive ms patients and study group sera tested at a dilution of 1:100 , respectively . room temperature incubation , pbs-0.05% tween 20 washes were followed by the addition of secondary antibodies ( goat ant - rabbit igg , sigma - aldrich , or rabbit anti - human igg conjugated with alkaline phosphatase , sigma - aldrich , respectively ) . p - nitrophenyl phosphate was used as the substrate ( sigma - aldrich ) and the reaction was stopped with 1 m hcl . the absorbance was measured with the elisa reader elx800 ( bio - tek ) at the wavelength of 405 nm . the above - mentioned procedure was carried out consecutively for plates coated with all the tested interferon preparations rebif , betaferon , and avonex . the results were expressed as the optical density ( o.d . ) , arbitrary units au / ml ( au arbitrary units ) , and reciprocal serum dilution ( rsd ) . arbitrary units were calculated according to the formula : ( 10 absorbance of tested sample)/absorbance of the cut - off values . the cut - off was established as 95th percentile of absorbance for each series of tested samples ( with rebif , betaferon , avonex as antigens ) performed in immunomodulatory treatment naive ms patients . cut - off values in tests using rebif as the antigen were 0.180 , for avonex0.208 and betaferon0.074 . reciprocal serum dilution was calculated according to the formula : [ 1 : x ] , where x is dilution of standard antibodies obtained from the fitting of standard curve . the standard curve fitting was based on the calculation of log log regression between absorbance and reciprocal standard dilution ( r = 0.9777 ) . then , the absorbances of tested samples were substituted to the regression formula and reciprocal serum dilutions were calculated . in our study , we have analyzed the sera from patients treated with rebif for the presence of babs by means of elisa , using rebif , avonex or betaferon formulations as immobilized antigens . different methods of magnitude of quantity expressions were evaluated for their clinical significance . in the group of 49 patients receiving interferon beta 1a , the presence of antibodies binding to rebif ( anti - rebif ) was found after 24 months of treatment in 12 patients ( 24,4% ) , when the cut - off was exceeded . the cut - off was established as the 95th percentile of o.d . in the group of treatment naive ms patients . within a year of the treatment discontinuation babs levels measured after 2 years of rebif therapy and 1 year after rebif treatment termination expressed in optical density units ( o.d . ) , arbitrary units ( au ) , and reciprocal serum dilution ( [ 1 : ] ) , where x is dilution . continuously high levels of antibodies were found in 8 patients , whereas 4 patients had a significant reduction in their level during the observation period . moreover , babs level expressed as reciprocal serum dilution was higher ( mean 167 12 vs 130 12 , p = 0.0428 ) in patients who manifested worsening from edss score evaluated after completion of ifnb treatment to edss score evaluated 1 year after therapy cessation than in subjects with a stable disability score . such an effect was not observed when the babs level was expressed as o.d . or in arbitrary units . thus , worsening at least in edss score can be used as indication of bab 's testing . we have analyzed roc curves for babs as markers of clinical worsening during ifnb treatment . as a classifier we have used hard clinical endpoints like increase in the edss score or relapse . when coexisting worsening in the edss score together with any relapse during ifnb therapy was used as clinical indicator of disease activity , babs identified after 2 years of rebif therapy were relevant . in such a group of patients bab 's expressed as reciprocal serum dilution , showed area under the curve ( auc ) of 0.671 with p = 0.0321 and a cut - off criterion of > 126 ( see fig . moreover , the presence of bab 's expressed as reciprocal serum dilution and evaluated 1 year after infb treatment termination ( auc = 0.655 , p = 0.0258 , cut - off criterion > 122 , fig . 2 ) and after 2 years of rebif therapy cessation ( auc = 0.637 , p = 0.0626 , cut - off criterion > 140 , fig . 3 ) predicted the worsening from edss evaluated after completion of ifnb treatment to edss score evaluated 1 year after therapy cessation . such effect was not found when babs were expressed as o.d . or arbitrary units . babs = binding antibodies , edss = expanded disability status scale , ifnb = interferon beta . roc curve for babs identified 1 year after ifnb termination and worsening from edss evaluated after completion of ifnb treatment ( edss2 ) to edss score evaluated 1 year after therapy cessation ( edss3 ) used as the classifier . babs = binding antibodies , edss = expanded disability status scale , ifnb = interferon beta . roc curve for babs evaluated after 2 years of inf treatment and worsening from edss evaluated after completion of ifnb treatment ( edss2 ) to edss score evaluated 1 year after therapy cessation ( edss 3 ) used as the classifier . babs = binding antibodies , edss = expanded disability status scale , ifnb = interferon beta . with the use of cut - off value exceeding 140 of reciprocal serum dilution , 45% of patients tested babs positive after 2 years of ifnb treatment , and 55% tested positive 1 year after ifnb therapy termination . the change of currently used infb formulation can be considered in patients who do not respond to therapy . the analysis of correlation between levels of different antibodies ( anti - rebif / anti- betaferon , anti - rebif / anti - avonex and anti - betaferon / anti - avonex ) for the study group was carried out . 0.0001 ) correlation between the level of anti - rebif antibodies with the level of anti - betaferon antibodies ( r1 correlation coefficient = 0.4578 and r2 = 0.8095 ; slope1 = 0.6179 and slope2 = 1.0823 ) was observed as illustrated in fig . 4 . correlation between anti - rebif antibodies and anti - betaferon antibodies : ( 1 ) after 2 years of rebif therapy , ( 2 ) 1 year after rebif treatment termination . reduced major axis ( rma ) regression was used to present the data . in rma regression measurement errors are taken into account for both dependent ( y - axis ) and independent ( x - axis ) variables . the level of anti - rebif antibodies also correlated ( r1 = 0.6531 and r2 = 0.6781 ; slope1 = 0.5945 and slope2 = 0.3695 ) with the level of anti - avonex antibodies ( p1 < 0.0001 ; p2 correlation between anti - rebif antibodies and anti - avonex antibodies : ( 1 ) after 2 years of rebif therapy , ( 2 ) 1 year after rebif treatment termination . reduced major axis ( rma ) regression was used to present the data . in rma regression measurement errors are taken into account for both dependent ( y - axis ) and independent ( x - axis ) variables . rma = reduced major axis . a strong correlation ( r1 = 0.8255 and r2 = 0.6819 ; slope1 = 1.2367 and slope2 = 1.5244 ) between levels of anti - betaferon and anti - avonex antibodies ( p1 < 0.0001 ; correlation between anti - betaferon antibodies and anti - avonex antibodies : ( 1 ) after 2 years of rebif therapy , ( 2 ) 1 year after rebif treatment termination . reduced major axis ( rma ) regression was used to present the data . in rma regression measurement errors are taken into account for both dependent ( y - axis ) and independent ( x - axis ) variables . in this study , we have confirmed that binding antibodies are formed in a significant ( 24.4% to 55% , depending on the time of evaluation and units used for their expression ) proportion of ifnb-1a treated patients , which is consistent with other publications . according to the literature , babs are present in 5% to 30% of patients on avonex , 25% to 45% in patients on rebif and 50% to 80% in those treated with betaferon . in comparison , neutralizing antibodies occur in 2% to 6% of patients treated with avonex , 12% to 28% in those treated with rebif , and in 28% to 47% of patients on betaferon . pharmacological forms of beta interferons differ in their immunogenicity ; therefore , there is a different proportion of patients with elevated levels of antibodies for different formulations . a golden - standard method for detection of anti - interferon antibodies is elisa , which has also been applied in our study . importantly , the united states and canadian authors demonstrated that the test reliability for the individual patient is better when one uses as the antigen the drug with which the patient has been treated . all of the commercially available preparations of ifnb ( at the time of patient recruitment these included : rebif , avonex i betaferon ) were used in this study . it should be noted that in our study , we only assessed the levels of babs , and not nabs . in our opinion , this does not diminish the significance of the results since international recommendations describe the assessment of babs as a first choice screening in rrms patients treated unsuccessfully with interferons . it has been demonstrated that babs titers reliably predict the presence of nabs . in the same study it was shown that babs diminish ifnb bioavailability independently from nabs , as measured by reduced protein concentrations of cxcl-10 and strail . in patients with elevated babs however , it is recommended to stop ifn - b treatment already at the moment when babs are present . the type of expression of babs level may play a role in its clinical significance and can be responsible for observed discrepancies between studies . most of the methods used for babs evaluation and analyzed in efns guidelines for anti - ifn measurements are based on o.d . or au and only one on the standard curve . thus , the limitations attributed to babs analyses may , additionally to biological effects , result from the units used for their expression . in our study we have shown the differences in clinical significance of babs , which depended on the type of magnitude of quantity . to our knowledge , there are no other studies comparing the effects of babs measurements expression on clinical evaluations . moreover , we used roc curve analysis since edss and relapse number are clinical hard endpoints revealing ms activity . thus , clinical outcomes of ms patients evaluation in everyday clinical practice are based on dichotomous results ( stable / worsened edss ; relapse / no relapse ) . the concept of roc curve uses the notion of a separator variable , which defines such outcomes . for this reason , we have tested a novel mode of expression of bab 's results ( reciprocal serum dilution ) using roc curve analysis . interestingly , in our study we did not find any statistically significant differences between serum antibody levels after 2 years of treatment with subcutaneous interferon beta 1a , and 1 year after treatment cessation . this suggests a continuously high level of antibodies reached within 2 years of treatment for at least another year . another interesting finding in our study is the presence of strong correlations between antibody levels for all the tested interferon formulations . these correlations were found between anti - rebif and anti - betaferon , anti - rebif and anti - avonex , as well as anti - avonex and anti - betaferon antibodies ( figs . 35 ) . in a very small earlier study by khan and dhib - jalbut 3 out of 10 patients treated with ifn beta 1a developed babs and nabs , both of which demonstrating cross - reactivity with interferon beta 1b similarly , antibodies in 6 patients treated with ifnb 1b cross - reacted with ifnb 1a . this study confirmed the results of previous observations that cross - reactivity between ifnb 1a and endogenous ifnb occurs in patients with high levels of antibody binding . similar results were obtained in subsequent studies and were consistent with the earlier findings . however , to our knowledge , so far the cross - immunogenicity of all the different commercially available interferons has not been estimated . this work is a pilot study and was conducted on a relatively small group of patients . a definite advantage of this study is the follow - up antibody levels assessment after a year since therapy withdrawal . we could , therefore , demonstrate the persistence of elevated anti - interferon antibody levels in the majority of patients after treatment discontinuation . we have also managed , with the use of roc curve analysis , to show that babs could be useful markers of clinical worsening during ifnb treatment . we believe these results have important implications for the clinical practice as they relate to commonly used ifnb formulations and confirm that in patients diagnosed with high levels of antibodies against any of the interferons one should expect high levels of babs against other interferon preparations . to conclude , if antibodies against any interferon are found , switching therapy to alternative disease - modifying agent should be considered . such therapeutic strategy could be effective even within the first - line therapy , as it has been proved recently . the results of the recent coptimise trial demonstrated that switching rrms patients who did not benefit from initial ifnb therapy to glatiramer acetate is associated with a positive treatment outcome . in light of the above - mentioned findings , different methods of expression of babs levels may be crucial for clinical purposes , and switching therapy from one interferon to another is not likely to benefit the patient . Output:	abstractinterferon beta ( ifnb ) preparations are commonly used as first - line therapy in relapsing - remitting multiple sclerosis ( rrms ) . they are , however , characterized by limited efficacy , partly due to the formation of anti - ifnb antibodies in patients.in this pilot study , we assessed with the elisa method the presence of the binding antibodies ( babs ) against interferon beta after 2 years of therapy with subcutaneous interferon beta 1a ( rebif ) in 49 rrms patients . antibody levels were established again within 1 year after treatment withdrawal . we used 3 interferons that are commercially available for ms therapy , namely avonex ( biogen idec limited ) , rebif ( merck serono ) , and betaferon ( bayer pharma ag ) , as antigens.babs reacting with rebif were found in 24.4% to 55% of patients , depending on the units of their expression . the levels of anti - rebif antibodies remained high in 8 patients and in 4 patients they dropped significantly . strong correlations were obtained in all assays ( anti - rebif - anti - avonex , anti - rebif - anti - betaferon , and anti - betaferon - anti - avonex ) and the existence of cross - reactivity in the formation of antibodies against all the tested formulations of interferon beta was confirmed . the levels of babs remain significant in the clinical context , and their assessment is the first choice screening ; however , methods of babs evaluation can be crucial for further decisions . more studies are needed to confirm our results ; specifically it would be of interest to evaluate methods of neutralizing antibodies identification , as we only assessed the binding antibodies . nevertheless , our results support the concept that in interferon nonresponders , that are positive for binding antibodies , switching the therapy to alternative disease - modifying agent ( for example glatiramer acetate , fingolimod , or natalizumab ) is justified , whereas the switch to another interferon formulation will probably be of no benefit .
PubmedSumm118816	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: tuberculous lesions of the liver may be unexpectedly detected during abdominal surgery . also , these lesions can , mistakenly , be diagnosed as tumour - like mass or cystic lesions in the liver on screening investigations . , we discuss two cases of hepatic tuberculosis due to diagnostic dilemma and rarity of these lesions . a 30-year - old woman was admitted to our hospital with a history of abdominal pain , anorexia , weight loss and fever for one month . on physical examination , except hepatomegaly , no other physical finding was detected . liver function tests ( alt 64 u / l , ast 76 u / l ) and alkaline phosphatase ( alp 310 ultrasonography ( us ) of the abdomen revealed a lobulated cystic mass with air in the right lobe of the liver . computerized tomography ( ct ) of the abdomen showed an ill - defined cystic mass with air - fluid level in the anterior segments of right liver lobe ( fig . 1 ) . liver abscess or infected hydatid disease was considered with these radiologic and clinical findings . histopathological examination of the specimen demonstrated granulomas , epithelioid histiocytes and langhans giant cells , and caseating granulomatous inflammation . unfortunately we did not perform culture of the specimen for tuberculosis , because tuberculosis was not taken in account in the differential diagnosis . a 63-year - old man was admitted to our hospital with abdominal pain and fever for one week . except for abdominal tenderness , physical examination was normal . only white blood cells ( 16,400/mm ) and liver function values ( alt 48 u / l , ast 52 abdominal us revealed a tumour - like mass lesion on the right lobe of the liver . histopathological examination of the specimen demonstrated granulomas , epithelioid histiocytes and langhans giant cells , and caseating granulomatous inflammation . tuberculosis is the leading cause of death among infectious diseases . among extra - pulmonary tuberculosis , described three morphologic types of hepatic tuberculosis : ( 1 ) miliary tuberculosis of the liver associated with generalized miliary tuberculosis , ( 2 ) primary miliary tuberculosis of the liver without involvement of other organs , and ( 3 ) primary tuberculous granuloma or abscesses of the liver . our two cases had only hepatic tuberculosis without pulmonary infection , which we accept as type 3 . the symptoms and signs of hepatic involvement are non - specific . similar to our cases mri and ct findings of liver tuberculosis reveal different stages of disease , varying from granulomatous tubercles with or without caseation necrosis to fibrosis and calcification in the healing stage . ct findings demonstrate miliary , hypodense nodular lesions or cystic lesion . in our cases , one of the patients had cystic mass with air - fluid level , and the other patient had tumour - like mass lesion . percutaneous needle biopsy and laparoscopy can be used for the diagnosis and occasionally laparotomy may be required in some patients . infectious and non - infectious diseases which can cause caseating or non - caseating hepatic granulomatous such as leprosy , sarcoidosis , hodgkin 's disease , brucellosis , infectious mononucleosis , inflammatory bowel disease , drug - induced liver damage and syphilis should be considered in the differential diagnosis of hepatic tuberculosis . antituberculous treatment should be given at least for one year ; however , many anti - tuberculous drugs are hepatotoxic and may induce liver damage and jaundice . therefore the response and toxicity should be assessed carefully during treatment . our patients were successfully treated for one year with anti - tuberculous drugs , and no side effect was observed during the treatment period . in conclusion , tuberculosis should be considered in the differential diagnosis of cystic and tumour - like mass lesions of the liver , especially in endemic regions . Output:	hepatic tuberculosis is a rare manifestation of extra - pulmonary tuberculosis . hepatic tuberculous lesions are especially mimicking tumour - like mass or cystic lesions in the liver and so can be misdiagnosed with several diseases . histopathological examination of the specimen is essential in the diagnosis for hepatic tuberculosis . in this report , two cases with hepatic tuberculosis having cystic solid mass and abscess liver lesions are described .
PubmedSumm118817	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: in developing countries , including iran , producing reliable information has reached its real position in recent years , but the necessary and useful application of this information has not found its place in various fields , including medicine . physicians responsible for patient management are faced with many questions , which they respond by using sources of information such as magazines and books , the information in clinical records , or by a combination of information about a particular patient with their basic knowledge of medicine . thus , providing treatment services to patients by the physicians requires more awareness about the updated information produced by researchers and medical professionals . the updated information is regarded as a constant higher education for the physician as it tells about the experiences and recommendation of his / her professional colleagues . due to the benefits of electronic information resources in comparison with published materials , such as quick release , ease of access , no time limitation , no restrictions in place and location , etc . based on the above - mentioned facts about the importance of timely use of medical information in the health and life of humans , and the characteristics of electronic information resources ( speed and ease ) , adoption and use of these resources is very important . on the other hand , one of the most important criteria for evaluating the usefulness of a technology is the rate of its usage . in evaluating the awareness and use of library users of the various information resources and the obstacles in using them properly , there have been extensive researches in the universities of the country and abroad and treatment centers , but none of these researches have paid attention to the evaluation of awareness and the usage of these resources together and the causes or obstacles in using these resources . among these studies , the following deserve mention . hajebi showed that the usage of information databases by the medical researchers has been very limited and only 2% of the researchers have used the embase database . etesami observed that 97.7% of the professionals used the medical library for solving their problems in the treatment of patients . baba rezaei kashani found in his study that 95.8% of the faculty members used the internet networks . the reasons for using the internet was to obtain updated information ( 55.6% ) and for conducting researches ( 41% ) . salmani nodoushan found in his study that sciencedirect database has been used more than the other sites and the lowest rate was for wiley database . in the study of tavassoli et al . , 11.1% of physicians were found to refer to internet for updating their information and 42.9% of them sought the assistance of their colleagues , go to the library , and search in the cd - roms , in addition to using internet . the results of mohammadi et al . , showed that regarding the use of electronic resources and the ways to access these resources , electronic journals had the highest usage compared to other resources . habibi et al . , observed the targets and used of the physicians to be in line with the development of new medications , observing the medical problems , determining the percentage of ardabil physicians in using medical databases , formal and informal channels used for specialized information , and their comments in connection with the fresh advances in medicine . mohammadi and abdolhoseinzadeh in their research concluded that among the 33 libraries , only 15 libraries in their reference department were using internet information resources . the main reason for their usage was to answer the questions in relation to conducting extensive researches . the findings from the research of abels et al . , showed that the studied faculty members used network services for teaching , research , be aware of the new contents , scientific and research communication , and paperwork . based on this research , the ease of physical access and attending a training program aimed to become familiar in using the service are the key factors in the use of computer networks . hurd et al . , showed that on average , 86% of the medical faculty and faculties of nursing and pharmacy in the university of illinois used medline , but medline was not enough to satisfy their information needs and they used printed and electronic resources too . mckibbon and douglas in their research came to the conclusion that due to poorly chosen resources , inappropriate searching strategy , and lack of sufficient time , the electronic resources were not providing the answers for medical questions . they stated that the librarians have an important role in the navigation of the users in the use of these resources . as observed , in all the studied researches , the importance of electronic information resources in the transfer of medical information is evident and has been proved for the users . but for various reasons , proper and expected use of these resources has not been performed ( despite the efforts of the libraries and information centers to provide the resources ) . in the present study , attention has been paid to determine the awareness of the physicians of the hospitals of isfahan university of medical sciences about the electronic resources and the factors influencing their usage or lack of use . the study population included all the 350 physicians and specialty physicians in the educational hospitals of isfahan university of medical sciences ( at the time of the study ) . by using the morgan 's formula , the required sample size was determined ( 180 physicians ) . the required information was collected by referring to the hospitals and clinics of the study population . the collected data were analyzed by spss software version 19 and using descriptive statistics and distribution and percentage frequency . demographic survey showed that 33 physicians ( 31.7% ) among the respondents were females and 71 of the respondents ( 68.3% ) were males . table 1 shows the various reasons of the physicians information requirements . in all the tables , distribution and frequency percentage of various reasons of the physicians information requirements it should be noted that obtaining new and updated information , conducting researches , and article production were cited as the reasons by most of the physicians for information requirement ( much and too much ) and the need for everyday information was the least cited reason . table 2 shows the distribution and percentage of frequency of the physicians usages of a variety of data resources . distribution and frequency percentage of the physicians usage from various data resources according to the data in the table , to obtain the needed information , the most used resource ( much and too much ) have been the printed and electronic information resources and lowest in the case has been the assistance to external experts . as it is observed , regarding the medicine databases , medline database was the best - known site among physicians and the lowest awareness has been associated with blackwell database . distribution of the physicians awareness about different databases table 3 shows the usage of electronic information resources by the physicians . distribution and frequency percentage of the physicians awareness and usage of various electronic information resources regarding the types of electronic resources , the maximum awareness ( much and too much ) was related to electronic journals and the least level of awareness was related to offline relevant databases . distribution and frequency percentage of the obstacles for the physicians in obtaining electronic information resources the obtained data show that being busy and lack of time ( 61.5% ) has been reported as the most important obstacle in using electronic information resources and lack of useful content resources was the least important obstacle . the present study shows that the studied physicians used information resources for reasons such as conducting researches , preparing articles , obtaining new and updated information , management of patients treatment , teaching , and finally , everyday usage . this indicates the continuous need of the physicians to obtain information for diagnosis and treatment of new cases . it has been reported in that study that the general practitioners aim for obtaining the latest information was to update their information for solving the health issues . as the findings of this study also revealed , the majority of surveyed physicians used different data resources to conduct researches . it has been demonstrated in that research that more than half of the study population used computer and internet for scientific and research activities . in the study of mohammadi et al . , it was observed that the main reason for the use of internet resources was to conduct researches . many physicians considered that the need for information is necessary in the context of teaching , which also confirms the importance of information in this case . according to the results of the study of torabi , among the reasons for using electronic medical resources , educational tasks formed 72.4% . the physicians make use of different data resources such as taking help of the expert collaborators within the country and the assistance of foreign experts to meet their information needs . they reported that the physicians use more of formal channels such as medical books and magazines for finding answers for clinical questions . among the informal channels of obtaining information , they received the required information by participating in continuing education courses , conferences , and informational congresses . electronic information resources are mostly used by the physician community . among the available databases , the awareness of the studied society in decreasing order was for the following : medline , elsevier , ovid journals , iran medex , springer , proquest , and blackwell . he reported that 29.6% of the studied population had awareness about the coverage of blackwell and ovid databases ( clinical sciences ) and 41.9% of the population had mostly used elsevier 's database . regarding the usage of various electronic information resources , the rate of awareness about online and offline databases , indicated that despite of their usefulness and easy access , these resources were not known . electronic books ( e - books ) had a similar situation with the online and offline databases . the studied physicians just had a relatively higher level of awareness in the case of electronic journals ( e - journal ) . the main reason may be cited as the availability of this in comparison with others resources . on the other hand , due to the limited shelf life of information in the medical field , and thus , the feature of information in the articles , and the sooner possibility to publish the journal compared to some other formats , this type of publication will be of most interest . there are several obstacles for the physicians in accessing and using the information they need and these obstacles lead to unavailability of timely and comprehensive information . the most important of these obstacles in the studied physicians was reported as being busy and lack of time , which has been also reported by other researches in this regard . according to the present study results , lack of sufficient awareness of electronic resources and not being familiar with the electronic resources retrieval methods are the other important obstacles . this finding is also consistent with the findings of other similar studies . in the studied population , there were a few physicians who mentioned about electronic resources shortage and lack of adequate electronic resources in the hospital library . therefore , despite the presence of a good collection in these libraries , more efforts need to be taken for the availability of the required resources . in contrary to these findings , mohammadi et al . , in their research , had concluded that lack of hardware and software facilities is the main reason for not using the internet . salmani nodoushan had reported that insufficient resources ( quantity ) and lack of internet access were of secondary importance . in the present era , more attention needs to be paid by the data centers on the information needs of the users and the informational community by considering the circumstances and technological progress in providing the best resources and training . due to the importance of electronic information resources for the medical community , and considering the fact that lack of awareness of these resources leads to less use of them , it requires careful planning by the library trustees and information centers of the hospitals in order to introduce the facilities and capabilities of the resources , especially the electronic resources . based on the obtained results , the following suggestions are offered : it is necessary that the libraries of the studied hospitals consider providing the needed technology and ways to facilitate the use of electronic resources more , and the managers should allocate more funds to increase the annual budget for electronic resources compared to printed resourcesit is necessary that the reference librarians and information centers in hospitals , by providing different communication styles , be always available for the physicians and respond to their immediate information needs during the treatment period with speed and easeit is necessary that training courses on the use of electronic resources be conducted as a part of the physicians retraining programs by medical librariansdue to lack of time of the physicians , it is recommended to use methods such as selective dissemination of information alert or rss by medical librarians to provide the physicians with the necessary information . it is necessary that the libraries of the studied hospitals consider providing the needed technology and ways to facilitate the use of electronic resources more , and the managers should allocate more funds to increase the annual budget for electronic resources compared to printed resources it is necessary that the reference librarians and information centers in hospitals , by providing different communication styles , be always available for the physicians and respond to their immediate information needs during the treatment period with speed and ease it is necessary that training courses on the use of electronic resources be conducted as a part of the physicians retraining programs by medical librarians due to lack of time of the physicians , it is recommended to use methods such as selective dissemination of information alert or rss by medical librarians to provide the physicians with the necessary information . based on the obtained results , the following suggestions are offered : it is necessary that the libraries of the studied hospitals consider providing the needed technology and ways to facilitate the use of electronic resources more , and the managers should allocate more funds to increase the annual budget for electronic resources compared to printed resourcesit is necessary that the reference librarians and information centers in hospitals , by providing different communication styles , be always available for the physicians and respond to their immediate information needs during the treatment period with speed and easeit is necessary that training courses on the use of electronic resources be conducted as a part of the physicians retraining programs by medical librariansdue to lack of time of the physicians , it is recommended to use methods such as selective dissemination of information alert or rss by medical librarians to provide the physicians with the necessary information . it is necessary that the libraries of the studied hospitals consider providing the needed technology and ways to facilitate the use of electronic resources more , and the managers should allocate more funds to increase the annual budget for electronic resources compared to printed resources it is necessary that the reference librarians and information centers in hospitals , by providing different communication styles , be always available for the physicians and respond to their immediate information needs during the treatment period with speed and ease it is necessary that training courses on the use of electronic resources be conducted as a part of the physicians retraining programs by medical librarians due to lack of time of the physicians , it is recommended to use methods such as selective dissemination of information alert or rss by medical librarians to provide the physicians with the necessary information . Output:	background : understanding of the medical society 's from the types of information resources for quick and easy access to information is an imperative task in medical researches and management of the treatment . the present study was aimed to determine the level of awareness of the physicians in using various electronic information resources and the factors affecting it.materials and methods : this study was a descriptive survey . the data collection tool was a researcher - made questionnaire . the study population included all the physicians and specialty physicians of the teaching hospitals affiliated to isfahan university of medical sciences and numbered 350 . the sample size based on morgan 's formula was set at 180 . the content validity of the tool was confirmed by the library and information professionals and the reliability was 95% . descriptive statistics were used including the spss software version 19.results:on reviewing the need of the physicians to obtain the information on several occasions , the need for information in conducting the researches was reported by the maximum number of physicians ( 91.9% ) and the usage of information resources , especially the electronic resources , formed 65.4% as the highest rate with regard to meeting the information needs of the physicians . among the electronic information databases , the maximum awareness was related to medline with 86.5% . among the various electronic information resources , the highest awareness ( 43.3% ) was related to the e - journals . the highest usage ( 36% ) was also from the same source . the studied physicians considered the most effective deterrent in the use of electronic information resources as being too busy and lack of time.conclusion:despite the importance of electronic information resources for the physician 's community , there was no comprehensive knowledge of these resources . this can lead to less usage of these resources . therefore , careful planning is necessary in the hospital libraries in order to introduce the facilities and full capabilities of the mentioned resources and methods of information retrieval .
PubmedSumm118818	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: curvatures in logarithmic plots of enzyme - catalyzed reactions were detected and discussed as early as 1949 by kistiakowsky and lumry in a paper on the hydrolysis of urea by urease , and described as widespread by maier and tappel in 1955 . among the many examples of curved arrhenius plots known for enzyme - catalyzed processes are the cleaving of rna by deoxyribozyme , the activation of spinach chloroplast fructose-1,6-biphosphatase , the catalytic activity of urocanase from pseudomonas putida , adenylate cyclase from saccharomyces cerevisiae , turnip peroxidase , bovine intestinal phosphatase , the kinetics of shiff base formation between a cholesterol ozonolysis product and dimyristoyl phosphatidyl ethanolamine , the activity of cyanobacterial adp - glucose pyrophosphorylase from anabaena , and the hydrolysis of various amides catalyzed by -chymotrypsin . among the explanations put forward to rationalize the observed curvature are the temperature - induced conformational change in the reactant , the assumption that the measured rate coefficient actually is a combination of elementary rate coefficients for a multiple - step reaction , or the notion that the derivative of hwith respect to temperature is negative , i. e. . the curvature of lnkr versus 1/t is thus viewed as a result of a more complex microscopic mechanism in turn composed of individual elementary steps that do follow transition state theory ( tst ) behavior . the shortcomings of tst have been discussed by pineda and schwartz , who describe promoting vibrations coupled to the reaction coordinate . while their computational analysis spans a time scale of tens of picosecond , this work focuses on the low - frequency , long - range motions of the whole protein on a time scale of up to one second for -chymotrypsin . the link between enzyme dynamics and hydrogen - transfer reactions was also discussed by knapp and klinman in the context of the environmentally coupled hydrogen tunneling model . their analysis rests on the relatively large debroglie wavelength for hydrogen , and was tested on a thermophilic alcohol dehydrogenase and soybean lipoxygenase-1 . among the extended formulations of tst , the ensemble - averaged variational transition - state theory with multidimensional tunneling ( ea - vtst / mt ) was successfully applied to many proton- or hydride - transfer reactions , as the interconversion of l - alanine and d - alanine catalyzed by alanine racemase , and the hydride transfer from nicotinamide adenine dinucleotide to flavin mononucleotide catalyzed by morphinone reductase . another way of interpreting the curvature of arrhenius plots has been described by masgrau and gonzlez - lafont , who postulate the temperature dependence of the activation energy . their analysis shows that curvature is present even in the absence of variational or tunneling effects , and the calculated arrhenius plots for two gas - phase reactions are convex at low temperature and concave at high temperatures . quite interestingly , the experimental arrhenius plots taken into account in our work , which is not by any means exhaustive , are , without exception , convex at any temperature , with the curvature being even more negative at higher temperatures . this difference could be a consequence of the condensed - phase environment of the reactions investigated in this work to evaluate the curvatures of arrhenius plots . in this series of tests , we extend the analysis of the nature of the temperature dependence of rate constants to any reaction , not necessarily involving hydrogen transfer or enzyme - catalyzed . we consider the possibility that the plots deviating from arrhenius behavior actually are relevant to elementary steps , and attempt to give a unitary rationalization of the above observations using a recently proposed relation between the rate coefficient and the potential energy barrier . it was shown for a model system that the coupling between vibrational modes is crucial to the energy transfer to the reaction coordinate . within this cooperative mechanism , the energy transfer from the low - frequency thermally excited vibrational modes to the reaction coordinate is the leading effect that promotes the barrier crossing from the michaelis complex to product . once the coupling between the medium and the reacting system is taken into account , the unimolecular rate coefficient for the process is given by ( 1 ) with = uts / kt being the reduced potential energy barrier . in ( 1 ) the quantities are the complete , incomplete , and regularized gamma functions of euler , respectively . the vibrational partition functions and z are relevant to the transition structure and the reagent , is the intrinsic response frequency of the reacting system once the threshold energy is acquired . the corresponding expression for bimolecular reactions in solution was subsequently given as(2 ) with kd the diffusion rate coefficient , and a non - dimensional ratio of response frequencies . a bimolecular reaction is envisioned as two reactant species a and b with total energy e colliding with formation of a vibrationally excited species c * , which in turn can revert back to reactants or evolve to products p with the energy - dependent unimolecular rate constants k-1(e ) and k2(e ) , respectively . the ratio of the response frequencies v-1/v2 is the parameter . the systems following ( 1 - 2 ) exhibit a number a of active modes energetically coupled to the reaction coordinate . in these cases , the non - exponential dependence of the rate constant of the potential energy leads to curved arrhenius and eyring plots . on the other hand , the unimolecular expression given by tst provides the exponential dependence(3 ) from the reduced barrier or , allowing for a more general system - dependent response frequency,(4 ) this work aims to establish whether the validity of ( 1 ) and ( 2 ) extends beyond the successful interpretations of the hydrolysis of amides by -chymotrypsin and the alkylation of 3-bromopyridine by iodomethane in acetonitrile . to this effect , the rate coefficient at different temperatures for various unimolecular , bimolecular , and enzyme - catalyzed reactions were examined , restricting the analysis to sets of data with at least four experimental points . by no means does the data discussed in this work cover the extensive literature reporting arrhenius and eyring plots for a wide variety of reacting systems . whenever possible , a statistical analysis on the standard deviations of the activation parameters induced by the error bars of the rate coefficients was carried out . neglecting the weak temperature dependence of the partition functions , we may express ( 1 , 2 , and 4 ) as(5 ) with or for a unimolecular or bimolecular process , respectively . this approximation is further justified by the consideration in the following treatment of the relative variation of the rate coefficient with respect to through the first and second derivatives of ln k , given by(7 ) the second derivative of ln ka of is in turn(8 ) typically , a - 1 < , \| ln ka\| < < 1 , and the sign of is negative . for a = 1 ( 7 ) and ( 8 , 9 ) reduce to the arrhenius behavior where(10 ) consequently , if ( 6 ) holds true , we should observe plots of ln k1 versus with constant slope and zero curvature . on the other hand , ( 5 ) gives a nonzero curvature of ln ka , as shown in figure 1 for the activation parameters of the hydride transfer catalyzed by escherichia coli dihydrofolate reductase . to obtain the parameters a , , and uts in ( 5 ) , unconstrained nonlinear regressions of experimental rate constants for various reactions were performed minimizing the deviation(12 ) plot of the curvature of ln ka versus for the hydride transfer catalyzed by escherichia coli dihydrofolate reductase , as given by ( 9 ) . with the simplex search method of lagarias . the form ( 12 ) of was chosen in order to have the same response for xi and . a typical value of = 2.10corresponds to a 15% average deviation . for comparison , constrained minimizations with a = 1 for all reactions ( equivalent to arrhenius plots ) were also performed , and the results are given in the supporting information [ additional file 1 ] . the set of reactions taken into consideration includes 13 unimolecular , 13 enzyme - catalyzed , and 12 bimolecular processes . among the unimolecular reactions , rate coefficients for a series of thermolyses of n - benzyl - n - nitrosopivalamides 4-r - c6h4-ch2-n(n = o)-c ( = o)-c(ch3)3 and n - benzyl - n - nitrosotosylamides these nitrosoamides undergo a rearrangement with elimination of n2 to give the corresponding benzyl esters . other unimolecular processes taken into consideration are the hydrolysis of trans - dinitrobis(ethylenediamine ) cobalt iii nitrate in various acids , the rearrangement of bis-(4-chlorophenyl ) thioncarbonate to bis-(4-chlorophenyl ) thiolcarbonate , the solvolysis of methyldiphenylsulfonium ion in water and ethanol . the temperature dependence of the rate coefficients for the neutral hydrolysis of methyl trifluoroacetate in h2o / dmso ( mole fraction of water 0.973 ) was investigated with particular care by euranto , whose results stand alone both for the number of experimental points and their accuracy . the unimolecular rate constants for the enzyme - catalyzed processes considered in this work are the oxidation of xanthine to uric acid by xanthine oxidase , the hydrolysis of amides catalyzed by -chymotrypsin , and the hydride transfer from nadph to 7,8-dihydrofolate catalyzed by escherichia coli dihydrofolate reductase in various solvents . in the logarithmic plots for enzyme - catalyzed processes the deviations from linearity are more evident . the bimolecular processes include the atom transfer radical polymerization of alkyl halides catalyzed by cu(i)br(pmdeta ) in acetonitrile , the hydration of co2 by water and oh , and the solvolysis of 4-methylbenzhydryl 4-nitrobenzoate in 90% acetone . the data obtained by the regression procedures are collected in tables 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 and 12 , where it is shown that in 29 out of 38 cases , the minima of are located in regions where a > 1 . activation parameters for the thermolyses of n - benzyl - n - nitrosoamides standard deviations are given in parentheses . activation parameters for the hydrolysis of trans - dinitrobis(ethylenediamine ) cobalt iii ion standard deviations are given in parentheses . activation parameters for the rearrangement of bis-(4-chlorophenyl ) thioncarbonate to bis-(4-chlorophenyl ) thiolcarbonate ( without solvent ) activation parameters for the solvolysis of methyldiphenylsulfonium ion in h2o and etoh standard deviations are given in parentheses . activation parameters for the neutral hydrolysis of methyl trifluoroacetate in h2o / dmso activation parameters for the oxidation of xanthine by xanthine oxidase activation parameters for hydrolyses catalyzed by -chymotrypsin standard deviations are given in parentheses . activation parameters for the hydride transfer catalyzed by escherichia coli dihydrofolate reductase in various solvents standard deviations are given in parentheses . calculated ( q(a,h)/q(a,d ) ) and experimental kinetic deuterium isotope effects at 20 c for the hydride transfer catalyzed by escherichia coli dihydrofolate reductase in various solvents the corresponding tst value is 7.15 . activation parameters for the atom transfer radical polymerization of alkyl halides catalyzed by cu(i)br(pmdeta ) in acetonitrile pmdeta = n , n , n',n',n''-pentamethyldiethylenetriamine . the alkyl halides include three -bromoesters , four -halonitriles , benzyl bromide , and allyl bromide . activation parameters for the hydration of carbon dioxide in water standard deviations are given in parentheses . activation parameters for the solvolysis of 4-methylbenzhydryl 4-nitrobenzoate in 90% acetone standard deviations are given in parentheses . concerning the physical interpretation of the above analysis , we envision a reacting system as a system composed of s oscillators with the reduced vibrational energy n(13 ) computed according to the debye model . in ( 13 ) we have xj = xc(j+1 ) , xc = hc/2kt , c = 2c / dc , with dc the diameter of the cluster , c the speed of sound in the medium , and s = d/c with d the debye frequency . thus , a reaction occurs if the energy is localized in one coordinate , according to tst , or in a coordinates if ( 5 ) is valid . we may have a qualitative picture of the relative probability of the two events if we consider each unit kt independent of others . in reality the localization of energy into a group of oscillators is a function of how much energy is already in that group , and the more energy is localized , the more intense will be the flow out . in this approximation of independent events , the probability to have energy localized in a group of a oscillators out of a total of s is given by a binomial distribution with the probability of each event p = a / sv(14 ) the quantity sv = 3v - 6 is the number of vibrational degrees of freedom in a region of given composition , nuclei number density , and volume v. assuming , for the sake of exemplification , the following functional forms a = sv/(sv + ) , = 0 + a , we may estimate c(n, ) . since the calculations involve the evaluation of euler 's gamma function for large arguments , the result is approximate and the distribution is normalized only in the region of small values of dc . treating both n and as continuous variables , we may evaluate the cumulative distribution function(15 ) plots of the total energy and f(n ) are given as a function of the cell size dc in figure 2 for 0 matching the hydride transfer catalyzed by escherichia coli dihydrofolate reductase in 17% methanol . plots of the total vibrational energy in a cluster versus the cluster size dc , the energy per vibrational degree of freedom , and the cumulative binomial distribution functions for one active mode ( green ) and a active modes ( blue ) . the reduced reaction barrier is taken from the hydride transfer catalyzed by escherichia coli dihydrofolate reductase in 17% methanol . ( a ) total energy in units of kt for a cluster solute - solvent of size 10 dc 80 according to the debye model . ( b ) ratio of the vibrational energy given by ( 13 ) in a water cluster over its number of vibrational degrees of freedom . ( c - d ) cumulative binomial distribution functions as a function of dc for p = 1/sv ( green ) and p = a / sv ( blue ) . * the reduced reaction barrier is taken from the hydride transfer catalyzed by escherichia coli dihydrofolate reductase in 17% methanol with = 200 and = 10 . * note that in ( d ) the blue curve lies above the green curve only for dc approximately above 20 , indicating the presence of a threshold size for the cooperative effect to take over . if a classical oscillators among the set of s are coupled to the reaction coordinate , we may estimate that the average energy akt is available to overcome the reaction barrier . in systems with optimal catalysis , the energy akt matches the potential energy barrier , giving the condition a/ 1 . in all cases with a/ < 1 , the coupling is not optimal and the rates are correspondingly slower . in all the tables we report the average value of in the experimental temperature interval [ t1 , t2 ] calculated as(16 ) the high potential energy barriers obtained with the minimization of are a consequence of the augmented size of the reacting system with respect to the substrate molecule . although the barrier of 143.96 kcal molobtained with ( 5 ) ( second entry in table 1 ) might be considered unusual , its high value is due to the participation of the solvent to the reaction coordinate . the gas - phase barriers obtained computationally may thus be regarded as lower limits to a much higher barrier in the condensed phase , augmented by the increase in potential energy due to change in coordinates of the medium to reach the transition structure of a large substrate - solvent cluster . an efficient catalytic system displays a prompt frequency response ( hz ) and a value of approaching unity . if both the frequency and are lower than unity the reaction rate is less than ideal . in order to estimate the error bars on the parameters obtained by nonlinear regression to ( 5 ) and ( 6 ) , we reoptimized all the parameters in 10000 runs after allowing the rate constants to vary according to a normal distribution with the experimentally determined variance ( the averaged variances for the rate coefficients of the reactions under consideration are : 16.9% for the thermolyses n - alkyl - n - nitrosopivalamides , 5% for the hydrolysis of dinitrobis(ethylenediamine ) cobalt iii ion , 4.0% for the solvolysis of methyldiphenylsulfonium ion , 0.04% for the hydrolysis of methyl trifluoroacetate , 8.7% for the hydrolyses catalyzed by -chymotrypsin , 4.7% for the hydride transfer catalyzed by escherichia coli dihydrofolate reductase , 7.1% for the hydration of co2 , and 1.9% for the solvolysis of 4-methylbenzhydryl 4-nitrobenzoate ) . the standard deviations for each activation parameter were determined and are given in tables 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 and 12 in parentheses . in all cases where the standard deviations are large , the parameters must be regarded as mere estimates . the arrhenius - type plots give much narrower error bars with respect to the plots obtained with ( 5 ) . for example , the standard deviation on reaction barriers with a = 1 lie all below 2 kcal mol , while , with the available experimental precision , some values of a exhibit a 50% error bar . thus the accuracy required in order to obtain small error bars on the activation parameters with ( 5 ) this degree of accuracy is matched by the excellent set of rate coefficients for the neutral hydrolysis of methyl trifluoroacetate in h2o / dmso , affording the paramenters in table 5 , which exhibit standard deviations in stark contrast with their counterparts in the remaining tables . the sets of data for the thermolyses of n - benzyl - n - nitrosoamides ( figures 3 - 4 , table 1 ) include only four experimentally measured rate coefficients for each reaction , and the values of are relatively high ( from 3.8710to 1.1410 ) . with the exception of the unsubstituted pivalamide ( which we consider an anomaly ) , the response frequencies for pivalamides are about 10hz , while for tosylamides they fall below this value . the response frequencies are higher for the hydrolysis of trans - dinitrobis(ethylenediamine ) cobalt iii nitrate ( figure 5 , table 2 ) , but the coupling is less effective , as exemplified by the lower values of ( 0.48 0.81 ) . the values of the parameters for the rearrangement of bis-(4-chlorophenyl ) thioncarbonate to bis-(4-chlorophenyl ) thiolcarbonate ( figure 6 , table 3 ) fall between the two previous cases , with a response frequency of the order of 10hz and . the solvolysis of methyldiphenylsulfonium ion in water is the first case where the minimum of is given by a regression with a = 1 , i.e. an arrhenius plot ( all the linear plots are shown in green in the figures ) . the corresponding hydrolysis in ethanol exhibits a curved plot ( figure 7 , table 4 ) with low values of both and . although the average curvature can in principle only be assigned with confidence in those cases where the experimental determinations exhibit sufficient accuracy , as in the neutral hydrolysis of methyl trifluoroacetate in h2o / dmso ( figure 8) , we might tentativley interpret the alternation between zero and non zero curvature as a result of the high sensitivity of the coupling between the substrate and the medium to the values of the parameters governing the dynamics of the cluster ( see the effect of the parameter in figure 2 ) . this sensitivity was demonstrated for a model system of two oscillators driven by an external force according to the debye theory of solids . the oxidation of xanthine to uric acid by xanthine oxidase affords the plot that deviates the most from linearity ( figure 9 , table 6 ) , even though the actual calculated average curvature is not high , due to the large span of values . in this case also the hydrolysis of amides by -chymotrypsin ( figure 10 , table 7 ) may be interpreted along the same lines , large values of both the response frequencies and the parameter . the reactions catalyzed by escherichia coli dihydrofolate reductase exhibits overall higher values for and lower ( for an enzyme ) values of ( figures 11 - 12 , table 8) with respect to the previous enzymes . also , four reactions out of nine have zero curvature , albeit two of them with high values of . the experimental values of the deuterium kinetic isotope effects for the hydride transfer catalyzed by escherichia coli dihydrofolate reductase in table 9 may be an indication that the cooperative mechanism is in effect for all solvents . in fact all kie values are in the range 2.60 3.22 , well below the estimated value of 7.15 given by classical transition state theory for a difference of 800 cmbetween the stretching frequencies c - h and c - d . the first bimolecular reaction of our analysis is the activation step of the atom transfer radical polymerization of alkyl halides catalyzed by cu(i)br(pdmeta ) ( pmdeta = n , n , n',n',n''-pentamethyldiethylenetriamine ) in acetonitrile ( figures 13 - 14 , table 10 ) . the measured rate constants are relevant to the cleavage of the c - x bond ( x = cl , br ) of various halides . with respect to the unimolecular and enzyme - catalyzed reactions discussed previously , this process exhibits low values of a and correspondingly low values of the activation barriers . values of are relatively high ( never below 310 , corresponding to an average deviation of 19% ) and the values of are lower than optimal . also , three processes have plots with zero curvature . both the hydration of co2 by water ( figure 15 , table 11 ) and the solvolysis of 4-methylbenzhydryl 4-nitrobenzoate in 90% acetone ( figure 16 , table 12 ) are cases of nearly linear plots with low values of a. the numerical analysis however reveals the non - zero curvature . in these cases , the experimental error may decide between linear and non linear plots and we are not in a position to draw firm conclusions . concerning the cases that exhibit a mixed behavior of zero and negative curvatures within the same class of reactions , we limit ourselves to the observation that the value of the deviation , averaged over the processes with zero curvature ( 6.04 10 ) is about twice the value averaged over the reactions of the same class with negative curvature ( 3.58 10 ) . logarithmic plots of rate coefficients for the thermolyses of n - benzyl - n - nitrosopivalamides 4-r - c6h4-ch2-n(n = o)-c ( = o)-c(ch3)3 in dmso . the experimental points are taken from ref . . logarithmic plots of rate coefficients for the thermolyses of n - benzyl - n - nitrosotosylamides c6h5-ch2-n(n = o)-so2-c6h4 - 4-ch3 in dmso ( a ) and toluene ( b ) . logarithmic plots of rate coefficients for the hydrolysis of dinitrobis(ethylenediamine ) cobalt iii ion in hbr 3.547 m ( a ) , h2so4 2.575 m ( b ) , and hno3 6.148 m ( c ) . logarithmic plots of rate coefficients for the rearrangement of bis-(4-chlorophenyl ) thioncarbonate to bis-(4-chlorophenyl ) thiolcarbonate . logarithmic plots of rate coefficients for the solvolysis of methyldiphenylsulfonium ion in h2o ( a ) and etoh ( b ) . . logarithmic plot of rate coefficients for the neutral hydrolysis of methyl trifluoroacetate in h2o / dmso . logarithmic plots of rate coefficients for the hydrolysis of suc - phe - pna ( a ) , suc - ala - phe - pna ( b ) , and suc - ala - ala - pro - phe - pna ( c ) catalyzed by -chymotrypsin . logarithmic plots of rate coefficients for the hydride transfer catalyzed by escherichia coli dihydrofolate reductase in water and methanol at various concentrations . logarithmic plots of rate coefficients for the hydride transfer catalyzed by escherichia coli dihydrofolate reductase in glycerol and sucrose at various concentrations . logarithmic plots of rate coefficients for the atom transfer radical polymerization of alkyl halides catalyzed by cu(i)br(pmdeta ) in acetonitrile ( see ref . 30 for the actual structures ) . logarithmic plots of rate coefficients for the atom transfer radical polymerization of alkyl halides catalyzed by cu(i)br(pmdeta ) in acetonitrile . logarithmic plots of rate coefficients for the hydration of carbon dioxide in water by h2o ( a ) and oh(b ) . although the high values of the standard deviations for the activation parameters obtained with ( 5 ) demand caution in their interpretation , we may qualitatively take the average curvature to measure the amount of deviation from tst caused by the cooperative mechanism , and outline four types of reactions : ( a ) systems with a limited coupling between the medium and the substrate that follow arrhenius behavior . in this group the conventional mechanism of exclusive energy transfer to the reaction coordinate is the fastest , with a resulting linear logarithmic plot ( figure 2c ) ; ( b ) systems with moderate to good coupling ( ) and low response frequencies ( 10 10hz ) . as the ability of the medium to effectively couple modes to the reaction coordinate grows , the coupled mechanism prevails for sufficiently large clusters ( figure 2d ) ; ( c ) systems with moderate coupling ( ) and high response frequencies ( 10 10hz ) ; ( d ) lastly , we may have the predominance of the cooperative mechanism with high response frequencies ( 10 10hz ) , and optimal coupling with in enzyme - catalyzed reactions . 1 . when the vibrational coupling between the substrate and the medium is taken into account , the rate coefficients of unimolecular and bimolecular reactions exhibit a dependence of the reduced potential energy barrier = uts / kt proportional to the regularized gamma function of euler q(a, ) . 2 . the deviations obtained from the experimental rate constants as a function of temperature using equation ( 5 ) are in many cases lower with respect to the standard tst equation . 3 . the corresponding activation energies exhibit considerably higher values with respect to the values obtained with tst , a fact ascribed to the much larger size of the system under consideration , which adds the contribution of the reaction medium to the intrinsic gas - phase barrier . 4 . the standard deviations on the activation parameters obtained using equation ( 5 ) are of the same order of magnitude as the parameter themselves , a fact that puts more stringent requirements on the accuracy of the experimentally determined rate coefficients . the reactions subjected to the above analysis may be divided into four groups according to the extent and the features of the substrate - medium coupling : ( a ) no coupling , linear logarithmic plots of kr versus ; ( b ) coupling with low response frequencies ; ( c ) coupling with high response frequencies ; ( d ) optimal coupling ( a/ 1 ) with very high response frequencies ( enzyme catalysis ) . the proposed expression for the rate constants of reactions in the condensed phase does not yet allow direct calculations of rate coefficients of chemical reactions , in that the physical parameters in the expression ( the reduced potential energy barrier , the intrinsic response frequency of the reacting system , and the number a of active modes energetically coupled to the reaction coordinate ) remain computationally elusive . however , its statistical nature is able to account for the negative curvatures of experimental arrhenius plots through the intrinsically non - exponential dependence of the rate constants from the reduced potential energy barrier . the supporting information reports the arrhenius activation parameters for all the reactions discussed in the text . the parameters were obtained with the same regression procedure outlined in the paper with the constraint a = 1 . Output:	in terms of the reduced potential energy barrier = uts / kt , the rate coefficients for chemical reactions are usually expressed as proportional to e-. the coupling between vibrational modes of the medium to the reaction coordinate leads to a proportionality of the regularized gamma function of euler q(a, ) = (a,)/(a ) , with a being the number of modes coupled to the reaction coordinate . in this work , the experimental rate coefficients at various temperatures for several chemical reactions were fitted to the theoretical expression in terms of q(a, ) to determine the extent of its validity and generality . the new expression affords lower deviations from the experimental points in 29 cases out of 38 and it accounts for the curvature in the logarithmic plots of rate coefficients versus inverse temperature . in the absence of tunneling , conventional theories predict the curvature of these plots to be identically zero .
PubmedSumm118819	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: at high field strengths ( 3 t and greater ) , the excitation radio - frequency ( rf ) wavelength becomes comparable to the size of the human body , causing strong coil tissue interactions which are subject - specific , depending on geometry and tissue electrical properties . the result of these interactions is an inhomogeneous rf transmit ( b1 ) field , which leads to spatially varying image contrast . furthermore , conventional single - channel rf systems generally have a one - time adjustment to match the rf coil to a nominal load presented by an average patient , whereas in fact the loading of the rf coil is subject - dependent , which can result in variable performance . the use of multiple transmit channels offers a means for mitigating these effects by allowing for greater control over the rf electromagnetic fields . rf shimming , in which a subject - specific adjustment is made to the relative amplitudes and phases of each transmit channel , can be used to improve b1 homogeneity and/or reduce sar . while such techniques have been technically demonstrated for transmit arrays with eight or more channels [ 2 , 3 ] , systematic clinical studies of rf shimming have primarily used commercially available two channel systems . rf shimming at 3 t has been used to stabilise and improve b1 homogeneity while achieving shorter image acquisition times compared with single - channel quadrature excitation , and to also improve diagnostic quality of resulting images . these improvements come directly from the ability to manipulate the spatial b1 distribution as a linear sum of contributing fields from individual coil elements:1\documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ s({\mathbf{r } } ) = \sum\limits_{i = 1}^{nc } { \sigma_{i } ( { \mathbf{r}})b_{i } } $ $ \end{document } in the above expression , i(r ) is the transmit sensitivity of the ith coil , nc is the total number of coils , s(r ) is the overall transmit sensitivity , and bi are complex weights applied to each channel . transmit sensitivity is defined as the ratio of the actual b1 field to the nominal value ; it is a dimensionless value which describes spatial variation of the field amplitude and phase . equation 1 shows that the ability to obtain uniform overall sensitivity depends on the sensitivities of the different coils in the array . it might be expected , therefore , that more coils , or perhaps different coil designs , would yield even larger improvements than a two - channel configuration . in this investigation , a 3 t mri scanner with eight physical transmit channels has been used to emulate different 2- , 4- and 8-channel configurations in vivo . possible benefits of rf shimming were assessed in a multiple - volunteer study focusing on b1 homogeneity , image quality and rf power reduction . experiments were performed using an 3 t achieva mri system ( philips healthcare , best , the netherlands ) equipped with an 8-channel parallel transmit ( ptx ) body coil . the coil consists of an array of eight elements , arranged around the bore of the magnet to give maximum spatial variation in transmit sensitivity in the axial plane . the overall transmit sensitivity of the array coil is a linear sum depending on the complex weighting applied to each channel ( eq . 1 ) . this can be rewritten in matrix form as s = b , where s is an n 1 vector ( n is the number of voxels ) , is an n nc sensitivity matrix and b is an nc 1 vector containing the complex coil weightings for each channel . for the system used , nc = 8 and b = [ 1 1 1 1 1 1 1 1 ] is defined as quadrature mode ( single - channel ) transmission . this definition of quadrature mode depends on the system being calibrated ; this will be discussed later . emulation of systems with a reduced number of channels can be performed by introducing an nc nr channel reduction matrix , r. this reduction matrix allows for emulation of systems with nr < nc channels via linear combinations of the scanner s physical channels . the transmit sensitivity is then written s = rb , and b represents the weightings applied now not to individual physical coils , but to the nr emulated channels . full control of the physical coils implies r is the nc nc identity matrix . the phase / amplitude relationship between all channels that defines quadrature mode is a property of the system hardware that must be determined by calibration . for our system , this is done using a standard phantom . however , it adds a bias to reduced channel combinations by locking in some aspects of the calibration . in order to reduce the effect that this has , a new system calibration matrix was computed by performing full 8-channel shimming on 10 previously acquired pelvic b1 maps ( 10 different subjects ) individually , then taking the complex average of all results for each channel . the resulting weights ci , which provide an optimised average starting shim , can be incorporated into a diagonal matrix , cii = ci which is included in the overall expression for the combined system sensitivity : s = crb . the calibration matrix was explicitly defined prior to any experimental work and not altered subsequently . rf shim weights were calculated using magnitude least squares ( mls ) optimisation [ 6 , 7 ] using the local variable exchange method 2\documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ { \text{b } } = { \hbox{min } } \left\ { { \ , \left\\| { \left\| { \sigma crb - \ , s_{target } } \right\| } \right\\|^ { 2 } + \ , \lambda \left\\| { \text{rb } } \right\\|^ { 2 } } \right\ } $ $ \end{document}starget is the target combined transmit sensitivity ; in this work starget = 1.0 for all space . note that the solution , b , has nr entries ; the actual weights applied to the nc physical coils are determined from the product rb . hence the second term in eq . 2 , which enumerates the total rf power , considers this product . the overall scaling of r is not important in the term \|\|rb\|\| since scalar factors in r can be subsumed into the parameter . several candidate reduction matrices for emulating 2- and 4-channel systems were tested on the pilot data . these were evaluated using eq . 2 with a range of values of to find the combinations that produced the optimal combination of b1 homogeneity and lowest total rf power when applied to the pilot data . the optimised 4-channel reduction matrix used in this study is shown below ; in this case adjacent coils were paired together , corresponding to creation of an enveloping array with fewer , larger coil elements placed adjacently.3\documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ { \mathbf{r}}^{t } = \left ( { \begin{array}{{20}c } 1 & 1 & 0 & 0 & 0 & 0 & 0 & 0 \\ 0 & 0 & 1 & 1 & 0 & 0 & 0 & 0 \\ 0 & 0 & 0 & 0 & 1 & 1 & 0 & 0 \\ 0 & 0 & 0 & 0 & 0 & 0 & 1 & 1 \\ \end{array } } \right ) . the first used the following reduction matrix4\documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ { \mathbf{r}}^{t } = \left ( { \begin{array}{{20}c } 1 & 1 & 0 & 0 & 1 & 1 & 0 & 0 \\ 0 & 0 & 1 & 1 & 0 & 0 & 1 & 1 \\ \end{array } } \right ) , $ $ \end{document}which was found to yield the best results in the pilot data . the second was chosen to emulate orthogonal , nominally linear modes of a 2-channel birdcage system and was defined as:5\documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ { \mathbf{r}}^{t } = \frac{1}{2}\left ( { \begin{array}{{20}c } 2 & { 1 - i } & 0 & { 1 + i } & 2 & { 1 - i } & 0 & { 1 + i } \\ 0 & { 1 + i } & 2 & { 1 - i } & 0 & { 1 + i } & 2 & { 1 - i } \\ \end{array } } \right ) . $ $ \end{document } for each subject , experiments were performed using the three different combination matrices described above , as well as 8-channel optimization ( r = i ) . in each case , error vs. power curves ( l - curves ) were plotted by performing the optimisation ( eq . 2 ) for multiple values of . the mls algorithm , implemented in matlab 2009b ( the mathworks , natick , ma ) on a desktop pc ( windows xp , dual core cpu 2.4 ghz , 2 gb ram ) , calculated all shim settings for a subject in less than 10 s , allowing for straightforward implementation in a scanning session . the curves were used to select two solutions for each case : the first maximised the homogeneity improvement obtainable whilst using the same rf power level as quadrature mode excitation , the second minimised the rf power level while maintaining approximately the same homogeneity as quadrature excitation . figure 1 shows how these solutions were obtained using l - curves calculated for one of the study subjects . imaging experiments were performed for the first solutions ( maximised homogeneity ) where measurable differences in b1 were expected ; in order to keep the examination duration within 1 h for each subject , the minimized power solutions were not used for imaging.fig . 1trade off between relative rf power and inhomogeneity ( rmse ) for different coil configurations . each curve is generated by performing the rf shimming calculation for multiple values of regularization parameter . solutions for constant rf power are indicated by the intersection of the horizontal dotted line with the other curves . solutions for constant homogeneity are indicated by intersection with the vertical dotted line trade off between relative rf power and inhomogeneity ( rmse ) for different coil configurations . each curve is generated by performing the rf shimming calculation for multiple values of regularization parameter . solutions for constant rf power are indicated by the intersection of the horizontal dotted line with the other curves . solutions for constant homogeneity are indicated by intersection with the vertical dotted line rf shimming experiments were carried out on healthy volunteers , with the focus being thigh and pelvis imaging . research ethics committee approval was obtained for the study , and all participants gave written informed consent prior to enrolment . in total , seven healthy volunteers ( two male , five female ) underwent pelvic and/or thigh scanning ( five volunteers underwent both ) . axial b1 field maps were acquired using the actual flip angle imaging sequence including a modified spoiling regime , slice profile correction and linear combination mapping to improve snr [ 1113 ] . imaging parameters were fov = 440 mm 220 mm , 64 32 matrix , slice thickness 10 mm , nominal flip angle = 80 and pulse repetition times of 30 ms and 150 ms . a t1-weighted turbo spin echo ( t1w - tse ) sequence ( 440 mm 220 mm fov , 400 318 matrix , tr = 605 ms , te = 10 ms , tse turbo factor = 3 ) and a t2-weighted turbo spin echo ( t2w - tse ) sequence ( 440 mm 220 mm fov , 400 318 matrix , tr = 2,000 ms , te = 100 ms , tse turbo factor = 10 ) were chosen for body imaging so the effect of varying the number of channels had on image quality could be assessed . the tse sequences outlined above are often used to acquire multiple interleaved slices ; use of a single slice allows the sar to be kept as low as possible while maintaining the same contrast parameters as used in clinical examinations . a full examination , consisting of b1 mapping , rf shim calculation and acquisition of images for all channel combinations , could be completed within 45 min . b1 maps were also obtained for each optimized shim setting to allow comparison between the predicted and achieved shimmed b1 distributions , independent of the receiver coil . accurate calculation of sar , particularly the local sar , requires subject specific e - field models based on the individual s anatomy . obtaining this information and completing the required calculations remains a challenge to achieve during an examination and is a current research topic in its own right [ 14 , 15 ] . in this study whole body sar was dealt with simplistically using the \|\|rb\|\| term in the rf shimming cost function ( eq . 2 ) . this method allowed for a time - efficient , indirect minimisation of global sar through the limiting of total rf power . a single - subject , single - position e - field model was also used to calculate the local sar prior to every scan performed using the method from ref . , allowing for quantification of the sar reduction potential of multiple transmit channels . the e - field model is for a large male subject , positioned with torso at isocentre , therefore the results acquired are unlikely to be accurate for different body shapes and different body positions relative to the rf coils . due to the uncertainty in the sar taken from this model , a maximum estimated sar level of 10 % of the relevant regulatory limit was allowed for any imaging sequence , to allow a tenfold margin for error . homogeneity was assessed for acquired b1 maps using both root mean square error ( rmse ) and coefficient of variation ( cv ) . both measures considered only the homogeneity of the magnitude of the measured b1 . rmse quantifies the deviation in absolute terms from the desired field pattern , and is equivalent to the square root of the first term in eq . 2 . the coefficient of variation ( standard deviation divided by mean ) is purely a measure of spatial homogeneity ; unlike rmse , cv is not altered by scaling the b1 fields . we hypothesised that increasing the number of channels would improve homogeneity , and therefore decrease the cv . smirnov tests were used to test the normality of the data ( there was no evidence for non - normality ) , then paired sample t - tests were used to examine differences in cv for incremental increases in the number of channels controlled ( 2 vs. 1 ( quad ) , 4 vs. 2 , 8 vs. 4 ) . the requirement for statistical significance was p < 0.05 for one - tailed comparisons ( i.e. the alternative hypothesis is that cv for the configuration with more channels is less ) . an experienced radiologist was given all images in a randomised order and asked to grade them according to a five - point scoring system , previously described by willinek et al . , but modified as all volunteers were healthy and no pathology was assessed . perceived image quality was rated on a scale of 15 , with 1 being an image of non - diagnostic quality and 5 demonstrating optimal contrast with no b1 inhomogeneity artefacts . the overall transmit sensitivity of the array coil is a linear sum depending on the complex weighting applied to each channel ( eq . 1 ) . this can be rewritten in matrix form as s = b , where s is an n 1 vector ( n is the number of voxels ) , is an n nc sensitivity matrix and b is an nc 1 vector containing the complex coil weightings for each channel . for the system used , nc = 8 and b = [ 1 1 1 1 1 1 1 1 ] is defined as quadrature mode ( single - channel ) transmission . this definition of quadrature mode depends on the system being calibrated ; this will be discussed later . emulation of systems with a reduced number of channels can be performed by introducing an nc nr channel reduction matrix , r. this reduction matrix allows for emulation of systems with nr < nc channels via linear combinations of the scanner s physical channels . the transmit sensitivity is then written s = rb , and b represents the weightings applied now not to individual physical coils , but to the nr emulated channels . full control of the physical coils implies r is the nc nc identity matrix . the phase / amplitude relationship between all channels that defines quadrature mode is a property of the system hardware that must be determined by calibration . for our system , this is done using a standard phantom . however , it adds a bias to reduced channel combinations by locking in some aspects of the calibration . in order to reduce the effect that this has , a new system calibration matrix was computed by performing full 8-channel shimming on 10 previously acquired pelvic b1 maps ( 10 different subjects ) individually , then taking the complex average of all results for each channel . the resulting weights ci , which provide an optimised average starting shim , can be incorporated into a diagonal matrix , cii = ci which is included in the overall expression for the combined system sensitivity : s = crb . the calibration matrix was explicitly defined prior to any experimental work and not altered subsequently . rf shim weights were calculated using magnitude least squares ( mls ) optimisation [ 6 , 7 ] using the local variable exchange method 2\documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ { \text{b } } = { \hbox{min } } \left\ { { \ , \left\\| { \left\| { \sigma crb - \ , s_{target } } \right\| } \right\\|^ { 2 } + \ , \lambda \left\\| { \text{rb } } \right\\|^ { 2 } } \right\ } $ $ \end{document}starget is the target combined transmit sensitivity ; in this work starget = 1.0 for all space . the regularisation parameter is designed to control total rf power . note that the solution , b , has nr entries ; the actual weights applied to the nc physical coils are determined from the product rb . hence the second term in eq . 2 , which enumerates the total rf power , considers this product . the overall scaling of r is not important in the term \|\|rb\|\| since scalar factors in r can be subsumed into the parameter . several candidate reduction matrices for emulating 2- and 4-channel systems were tested on the pilot data . these were evaluated using eq . 2 with a range of values of to find the combinations that produced the optimal combination of b1 homogeneity and lowest total rf power when applied to the pilot data . the optimised 4-channel reduction matrix used in this study is shown below ; in this case adjacent coils were paired together , corresponding to creation of an enveloping array with fewer , larger coil elements placed adjacently.3\documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ { \mathbf{r}}^{t } = \left ( { \begin{array}{{20}c } 1 & 1 & 0 & 0 & 0 & 0 & 0 & 0 \\ 0 & 0 & 1 & 1 & 0 & 0 & 0 & 0 \\ 0 & 0 & 0 & 0 & 1 & 1 & 0 & 0 \\ 0 & 0 & 0 & 0 & 0 & 0 & 1 & 1 \\ \end{array } } \right ) . the first used the following reduction matrix4\documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ { \mathbf{r}}^{t } = \left ( { \begin{array}{{20}c } 1 & 1 & 0 & 0 & 1 & 1 & 0 & 0 \\ 0 & 0 & 1 & 1 & 0 & 0 & 1 & 1 \\ \end{array } } \right ) , $ $ \end{document}which was found to yield the best results in the pilot data . the second was chosen to emulate orthogonal , nominally linear modes of a 2-channel birdcage system and was defined as:5\documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ { \mathbf{r}}^{t } = \frac{1}{2}\left ( { \begin{array}{{20}c } 2 & { 1 - i } & 0 & { 1 + i } & 2 & { 1 - i } & 0 & { 1 + i } \\ 0 & { 1 + i } & 2 & { 1 - i } & 0 & { 1 + i } & 2 & { 1 - i } \\ \end{array } } \right ) . for each subject , experiments were performed using the three different combination matrices described above , as well as 8-channel optimization ( r = i ) . in each case , error vs. power curves ( l - curves ) were plotted by performing the optimisation ( eq . 2 ) for multiple values of . the mls algorithm , implemented in matlab 2009b ( the mathworks , natick , ma ) on a desktop pc ( windows xp , dual core cpu 2.4 ghz , 2 gb ram ) , calculated all shim settings for a subject in less than 10 s , allowing for straightforward implementation in a scanning session . the curves were used to select two solutions for each case : the first maximised the homogeneity improvement obtainable whilst using the same rf power level as quadrature mode excitation , the second minimised the rf power level while maintaining approximately the same homogeneity as quadrature excitation . figure 1 shows how these solutions were obtained using l - curves calculated for one of the study subjects . imaging experiments were performed for the first solutions ( maximised homogeneity ) where measurable differences in b1 were expected ; in order to keep the examination duration within 1 h for each subject , the minimized power solutions were not used for imaging.fig . 1trade off between relative rf power and inhomogeneity ( rmse ) for different coil configurations . each curve is generated by performing the rf shimming calculation for multiple values of regularization parameter . solutions for constant rf power are indicated by the intersection of the horizontal dotted line with the other curves . solutions for constant homogeneity are indicated by intersection with the vertical dotted line trade off between relative rf power and inhomogeneity ( rmse ) for different coil configurations . each curve is generated by performing the rf shimming calculation for multiple values of regularization parameter . solutions for constant rf power are indicated by the intersection of the horizontal dotted line with the other curves . rf shimming experiments were carried out on healthy volunteers , with the focus being thigh and pelvis imaging . research ethics committee approval was obtained for the study , and all participants gave written informed consent prior to enrolment . in total , seven healthy volunteers ( two male , five female ) underwent pelvic and/or thigh scanning ( five volunteers underwent both ) . axial b1 field maps were acquired using the actual flip angle imaging sequence including a modified spoiling regime , slice profile correction and linear combination mapping to improve snr [ 1113 ] . imaging parameters were fov = 440 mm 220 mm , 64 32 matrix , slice thickness 10 mm , nominal flip angle = 80 and pulse repetition times of 30 ms and 150 ms . a t1-weighted turbo spin echo ( t1w - tse ) sequence ( 440 mm 220 mm fov , 400 318 matrix , tr = 605 ms , te = 10 ms , tse turbo factor = 3 ) and a t2-weighted turbo spin echo ( t2w - tse ) sequence ( 440 mm 220 mm fov , 400 318 matrix , tr = 2,000 ms , te = 100 ms , tse turbo factor = 10 ) were chosen for body imaging so the effect of varying the number of channels had on image quality could be assessed . the tse sequences outlined above are often used to acquire multiple interleaved slices ; use of a single slice allows the sar to be kept as low as possible while maintaining the same contrast parameters as used in clinical examinations . a full examination , consisting of b1 mapping , rf shim calculation and acquisition of images for all channel combinations , could be completed within 45 min . b1 maps were also obtained for each optimized shim setting to allow comparison between the predicted and achieved shimmed b1 distributions , independent of the receiver coil . accurate calculation of sar , particularly the local sar , requires subject specific e - field models based on the individual s anatomy . obtaining this information and completing the required calculations remains a challenge to achieve during an examination and is a current research topic in its own right [ 14 , 15 ] . in this study whole body sar was dealt with simplistically using the \|\|rb\|\| term in the rf shimming cost function ( eq . 2 ) . this method allowed for a time - efficient , indirect minimisation of global sar through the limiting of total rf power . a single - subject , single - position e - field model was also used to calculate the local sar prior to every scan performed using the method from ref . , allowing for quantification of the sar reduction potential of multiple transmit channels . the e - field model is for a large male subject , positioned with torso at isocentre , therefore the results acquired are unlikely to be accurate for different body shapes and different body positions relative to the rf coils . due to the uncertainty in the sar taken from this model , a maximum estimated sar level of 10 % of the relevant regulatory limit was allowed for any imaging sequence , to allow a tenfold margin for error . homogeneity was assessed for acquired b1 maps using both root mean square error ( rmse ) and coefficient of variation ( cv ) . both measures considered only the homogeneity of the magnitude of the measured b1 . rmse quantifies the deviation in absolute terms from the desired field pattern , and is equivalent to the square root of the first term in eq . 2 . the coefficient of variation ( standard deviation divided by mean ) is purely a measure of spatial homogeneity ; unlike rmse , cv is not altered by scaling the b1 fields . we hypothesised that increasing the number of channels would improve homogeneity , and therefore decrease the cv . smirnov tests were used to test the normality of the data ( there was no evidence for non - normality ) , then paired sample t - tests were used to examine differences in cv for incremental increases in the number of channels controlled ( 2 vs. 1 ( quad ) , 4 vs. 2 , 8 vs. 4 ) . < 0.05 for one - tailed comparisons ( i.e. the alternative hypothesis is that cv for the configuration with more channels is less ) . an experienced radiologist was given all images in a randomised order and asked to grade them according to a five - point scoring system , previously described by willinek et al . , but modified as all volunteers were healthy and no pathology was assessed . perceived image quality was rated on a scale of 15 , with 1 being an image of non - diagnostic quality and 5 demonstrating optimal contrast with no b1 inhomogeneity artefacts . a consistent pattern of substantial inhomogeneity was found in the b1 field generated by quadrature excitation , in both the pelvis and thighs of all volunteers . the inhomogeneity was characterised by diagonally offset areas of low b1 intensity in the anterior and posterior regions . this resulted in areas of very low signal intensity in the resulting t1w - tse images ; the t2w - tse images were more robust to the inhomogeneity . the b1 fields and the corresponding t1w and t2w images acquired in quadrature mode for all volunteers are shown in fig . 2 for the pelvis and fig . 3 for the thighs . note that the variability seen in the average b1 value between different subjects in fig . 2 is the result of inaccuracy in the scanner s standard global power - optimisation procedure .fig . axial afi transmit sensitivity maps ( s(r ) ) ( top ) , t1w - tse images ( middle ) and t2w - tse images ( bottom ) . note that the t2w image is missing for one volunteer because technical problems led to the examination being terminated before all data had been acquiredfig . axial afi transmit sensitivity maps ( top ) , t1w - tse images ( middle ) and t2w - tse images ( bottom ) . significant areas of low sensitivity are seen in the upper right and lower left portions of the field of view with corresponding shading artefacts present on the t1w and t2w images nominal quadrature mode axial pelvis results for multiple volunteers . axial afi transmit sensitivity maps ( s(r ) ) ( top ) , t1w - tse images ( middle ) and t2w - tse images ( bottom ) . note that the t2w image is missing for one volunteer because technical problems led to the examination being terminated before all data had been acquired nominal quadrature mode axial thigh results for multiple volunteers . axial afi transmit sensitivity maps ( top ) , t1w - tse images ( middle ) and t2w - tse images ( bottom ) . significant areas of low sensitivity are seen in the upper right and lower left portions of the field of view with corresponding shading artefacts present on the t1w and t2w images figure 4 contains rf homogeneity , power and sar estimates for the pelvis and thigh experiments . all shim solutions had an approximately constant rf forward drive , relative to quadrature mode , as can be seen in parts e , f. the maximum local sar as indicated by the e - field model based sar calculator is displayed on parts g , h ; note that the local sar measurements are quoted for the afi b1 mapping sequence . this figure shows that by increasing the number of transmit channels , the b1 field can be made progressively more homogeneous for both the pelvis and thighs . the results of paired sample t - tests comparing cv for configurations with successively increasing numbers of channels showed that improvements were significant ( table 1 ) for both anatomies studied and for all increases in channel number . examples of the effect of these improvements in single volunteers can be seen in figs . 5 and 6 , which contain the b1 maps , t1w - tse and t2w - tse images obtained for each configuration from a single volunteer.fig . pelvis results are shown in the left hand column , with thigh results in the right column . the maximum whisker length on all box plots is 1.5 the interquartile range ; all points outside this are deemed outliers and marked with a red cross note that both rmse ( a / b ) and cv ( c / d ) were measured from acquired b1 maps , e , f rf power was held constant with respect to quadrature mode . g , h local sar estimate from numerical model for afi b1 mapping sequence versus channel configurationtable 1table of p values for pairwise comparison of c v measured from acquired b1 maps for configurations with increasing numbers of channelsanatomy p values2-channel ( opt ) compared with quadrature4-channel compared with 2-channel ( opt)8-channel compared with 4-channelpelvis0.00260.00050.0075thigh0.00380.00200.0004taking 0.05 as the threshold for significance , increasing from one to two , two to four channels and four to eight channels yielded significant improvements in homogeneity in all cases . note that only the optimal 2-channel configuration ( not the birdcage configuration ) is shown here to reduce the number of comparisonsfig . top afi axial pelvic s(r ) maps , middle t1w - tse and bottom t2w - tse axial pelvic images ; columns from left to right : quadrature , 2-channel ( birdcage ) , 2-channel ( optimal ) , 4-channel and 8-channel . the t2w images appear more robust to b1 inhomogeneity than the t1w sequencefig . top afi axial thigh s(r ) maps , middle t1w - tse and bottom t2w - tse axial pelvic images ; columns from left to right : quadrature , 2-channel ( birdcage ) , 2-channel ( optimal ) , 4-channel and 8-channel . the t2w images appear more robust to b1 inhomogeneity than the t1w sequence results for experiments designed to maximise homogeneity at constant rf power . pelvis results are shown in the left hand column , with thigh results in the right column . the maximum whisker length on all box plots is 1.5 the interquartile range ; all points outside this are deemed outliers and marked with a red cross . note that both rmse ( a / b ) and cv ( c / d ) were measured from acquired b1 maps , e , f rf power was held constant with respect to quadrature mode . g , h local sar estimate from numerical model for afi b1 mapping sequence versus channel configuration table of p values for pairwise comparison of c v measured from acquired b1 maps for configurations with increasing numbers of channels taking 0.05 as the threshold for significance , increasing from one to two , two to four channels and four to eight channels yielded significant improvements in homogeneity in all cases . note that only the optimal 2-channel configuration ( not the birdcage configuration ) is shown here to reduce the number of comparisons example data from pelvis scans of one volunteer . top afi axial pelvic s(r ) maps , middle t1w - tse and bottom t2w - tse axial pelvic images ; columns from left to right : quadrature , 2-channel ( birdcage ) , 2-channel ( optimal ) , 4-channel and 8-channel . the t2w images appear more robust to b1 inhomogeneity than the t1w sequence example data from thigh scans of one volunteer . top afi axial thigh s(r ) maps , middle t1w - tse and bottom t2w - tse axial pelvic images ; columns from left to right : quadrature , 2-channel ( birdcage ) , 2-channel ( optimal ) , 4-channel and 8-channel . the t2w images appear more robust to b1 inhomogeneity than the t1w sequence the mean maximum local sar measurements from the online sar model decreased with increasing numbers of channels for the pelvis experiment , although 4- and 8-channel configurations performed similarly . in the thighs there was also a gradual reduction with the exception of the 2-channel ( non - birdcage ) configuration which achieved a much lower calculated average local sar than the other configurations . when transmitting in single - channel ( nominal quadrature ) mode , the maximum local sar for the afi sequence is always 3 w / kg according to the experimental online electric field model as no phase / amplitude modifications have been made and the system is calibrated . the blind grading results from the anatomical images for all coil configurations averaged over all subjects are displayed in table 2 . in the case of the t1w images , increasing channel numbers also increases perceived image performance for both anatomies tested . for pelvic imaging there were no perceived improvements in the t2w images when increasing the number of transmit channels ; however , a slight improvement was noted when imaging the thighs.table 2results of blinded image quality grading ( mean sd across all subjects ) using five point scale adapted from willinek et al . anatomyimaging sequencequadrature2-channel ( birdcage)2-channel ( optimal)4-channel8-channelpelvist1w4.00 0.634.33 0.524.33 0.524.50 0.554.67 0.52t2w4.20 0.454.60 0.554.60 0.554.60 0.554.60 0.55thight1w2.50 0.553.20 0.843.67 1.034.33 0.524.67 0.52t2w4.00 0.634.60 0.554.60 0.554.83 0.414.83 0.41 results of blinded image quality grading ( mean sd across all subjects ) using five point scale adapted from willinek et al . for all experiments , optimized rf shims were also computed for minimizing rf power ( quantified by \|\|rb\|\| ) while maintaining a fixed homogeneity level ( constant rmse ) . no imaging was performed for these solutions ; b1 homogeneity was instead estimated from the predicted field maps for the solutions found . the total rf power reduces as the number of channels increases , with the 8-channel system having the lowest power requirement . the predicted local sar is also reduced for channel counts higher than one , however these do not follow the same pattern as total rf power . 7comparisons of homogeneity , power requirements and local sar with different numbers of channels when performing rf shimming at a fixed level of homogeneity . unlike fig . 4 , homogeneity values ( rmse / cv ) are predicted rather than measured . a , b rmse is held the same for all configurations ; variability comes from inter - subject differences . c , d cv falls with increasing channel count , indicating that although the rmse is held constant the actual field patterns do vary . g , h local sar prediction of afi b1 mapping sequence acquired with power reduction shims comparisons of homogeneity , power requirements and local sar with different numbers of channels when performing rf shimming at a fixed level of homogeneity . unlike fig . 4 , homogeneity values ( rmse / cv ) are predicted rather than measured . a , b rmse is held the same for all configurations ; variability comes from inter - subject differences . c , d cv falls with increasing channel count , indicating that although the rmse is held constant the actual field patterns do vary . g , h local sar prediction of afi b1 mapping sequence acquired with power reduction shims a consistent pattern of substantial inhomogeneity was found in the b1 field generated by quadrature excitation , in both the pelvis and thighs of all volunteers . the inhomogeneity was characterised by diagonally offset areas of low b1 intensity in the anterior and posterior regions . this resulted in areas of very low signal intensity in the resulting t1w - tse images ; the t2w - tse images were more robust to the inhomogeneity . the b1 fields and the corresponding t1w and t2w images acquired in quadrature mode for all volunteers are shown in fig . 2 for the pelvis and fig . 3 for the thighs . note that the variability seen in the average b1 value between different subjects in fig . 2 is the result of inaccuracy in the scanner s standard global power - optimisation procedure .fig . axial afi transmit sensitivity maps ( s(r ) ) ( top ) , t1w - tse images ( middle ) and t2w - tse images ( bottom ) . note that the t2w image is missing for one volunteer because technical problems led to the examination being terminated before all data had been acquiredfig . axial afi transmit sensitivity maps ( top ) , t1w - tse images ( middle ) and t2w - tse images ( bottom ) . significant areas of low sensitivity are seen in the upper right and lower left portions of the field of view with corresponding shading artefacts present on the t1w and t2w images nominal quadrature mode axial pelvis results for multiple volunteers . axial afi transmit sensitivity maps ( s(r ) ) ( top ) , t1w - tse images ( middle ) and t2w - tse images ( bottom ) . note that the t2w image is missing for one volunteer because technical problems led to the examination being terminated before all data had been acquired nominal quadrature mode axial thigh results for multiple volunteers . axial afi transmit sensitivity maps ( top ) , t1w - tse images ( middle ) and t2w - tse images ( bottom ) . significant areas of low sensitivity are seen in the upper right and lower left portions of the field of view with corresponding shading artefacts present on the t1w and t2w images figure 4 contains rf homogeneity , power and sar estimates for the pelvis and thigh experiments . all shim solutions had an approximately constant rf forward drive , relative to quadrature mode , as can be seen in parts e , f. the maximum local sar as indicated by the e - field model based sar calculator is displayed on parts g , h ; note that the local sar measurements are quoted for the afi b1 mapping sequence . this figure shows that by increasing the number of transmit channels , the b1 field can be made progressively more homogeneous for both the pelvis and thighs . the results of paired sample t - tests comparing cv for configurations with successively increasing numbers of channels showed that improvements were significant ( table 1 ) for both anatomies studied and for all increases in channel number . examples of the effect of these improvements in single volunteers can be seen in figs . 5 and 6 , which contain the b1 maps , t1w - tse and t2w - tse images obtained for each configuration from a single volunteer.fig . pelvis results are shown in the left hand column , with thigh results in the right column . the maximum whisker length on all box plots is 1.5 the interquartile range ; all points outside this are deemed outliers and marked with a red cross note that both rmse ( a / b ) and cv ( c / d ) were measured from acquired b1 maps , e , f rf power was held constant with respect to quadrature mode . g , h local sar estimate from numerical model for afi b1 mapping sequence versus channel configurationtable 1table of p values for pairwise comparison of c v measured from acquired b1 maps for configurations with increasing numbers of channelsanatomy p values2-channel ( opt ) compared with quadrature4-channel compared with 2-channel ( opt)8-channel compared with 4-channelpelvis0.00260.00050.0075thigh0.00380.00200.0004taking 0.05 as the threshold for significance , increasing from one to two , two to four channels and four to eight channels yielded significant improvements in homogeneity in all cases . note that only the optimal 2-channel configuration ( not the birdcage configuration ) is shown here to reduce the number of comparisonsfig . top afi axial pelvic s(r ) maps , middle t1w - tse and bottom t2w - tse axial pelvic images ; columns from left to right : quadrature , 2-channel ( birdcage ) , 2-channel ( optimal ) , 4-channel and 8-channel . the t2w images appear more robust to b1 inhomogeneity than the t1w sequencefig . top afi axial thigh s(r ) maps , middle t1w - tse and bottom t2w - tse axial pelvic images ; columns from left to right : quadrature , 2-channel ( birdcage ) , 2-channel ( optimal ) , 4-channel and 8-channel . the t2w images appear more robust to b1 inhomogeneity than the t1w sequence results for experiments designed to maximise homogeneity at constant rf power . pelvis results are shown in the left hand column , with thigh results in the right column . the maximum whisker length on all box plots is 1.5 the interquartile range ; all points outside this are deemed outliers and marked with a red cross . note that both rmse ( a / b ) and cv ( c / d ) were measured from acquired b1 maps , e , f rf power was held constant with respect to quadrature mode . g , h local sar estimate from numerical model for afi b1 mapping sequence versus channel configuration table of p values for pairwise comparison of c v measured from acquired b1 maps for configurations with increasing numbers of channels taking 0.05 as the threshold for significance , increasing from one to two , two to four channels and four to eight channels yielded significant improvements in homogeneity in all cases . note that only the optimal 2-channel configuration ( not the birdcage configuration ) is shown here to reduce the number of comparisons example data from pelvis scans of one volunteer . top afi axial pelvic s(r ) maps , middle t1w - tse and bottom t2w - tse axial pelvic images ; columns from left to right : quadrature , 2-channel ( birdcage ) , 2-channel ( optimal ) , 4-channel and 8-channel . the t2w images appear more robust to b1 inhomogeneity than the t1w sequence example data from thigh scans of one volunteer . top afi axial thigh s(r ) maps , middle t1w - tse and bottom t2w - tse axial pelvic images ; columns from left to right : quadrature , 2-channel ( birdcage ) , 2-channel ( optimal ) , 4-channel and 8-channel . the t2w images appear more robust to b1 inhomogeneity than the t1w sequence the mean maximum local sar measurements from the online sar model decreased with increasing numbers of channels for the pelvis experiment , although 4- and 8-channel configurations performed similarly . in the thighs there was also a gradual reduction with the exception of the 2-channel ( non - birdcage ) configuration which achieved a much lower calculated average local sar than the other configurations . when transmitting in single - channel ( nominal quadrature ) mode , the maximum local sar for the afi sequence is always 3 w / kg according to the experimental online electric field model as no phase / amplitude modifications have been made and the system is calibrated . the blind grading results from the anatomical images for all coil configurations averaged over all subjects are displayed in table 2 . in the case of the t1w images , increasing channel numbers also increases perceived image performance for both anatomies tested . for pelvic imaging there were no perceived improvements in the t2w images when increasing the number of transmit channels ; however , a slight improvement was noted when imaging the thighs.table 2results of blinded image quality grading ( mean sd across all subjects ) using five point scale adapted from willinek et al . anatomyimaging sequencequadrature2-channel ( birdcage)2-channel ( optimal)4-channel8-channelpelvist1w4.00 0.634.33 0.524.33 0.524.50 0.554.67 0.52t2w4.20 0.454.60 0.554.60 0.554.60 0.554.60 0.55thight1w2.50 0.553.20 0.843.67 1.034.33 0.524.67 0.52t2w4.00 0.634.60 0.554.60 0.554.83 0.414.83 0.41 results of blinded image quality grading ( mean sd across all subjects ) using five point scale adapted from willinek et al . for all experiments , optimized rf shims were also computed for minimizing rf power ( quantified by \|\|rb\|\| ) while maintaining a fixed homogeneity level ( constant rmse ) . no imaging was performed for these solutions ; b1 homogeneity was instead estimated from the predicted field maps for the solutions found . the total rf power reduces as the number of channels increases , with the 8-channel system having the lowest power requirement . the predicted local sar is also reduced for channel counts higher than one , however these do not follow the same pattern as total rf power . 7comparisons of homogeneity , power requirements and local sar with different numbers of channels when performing rf shimming at a fixed level of homogeneity . unlike fig . 4 , homogeneity values ( rmse / cv ) are predicted rather than measured . a , b rmse is held the same for all configurations ; variability comes from inter - subject differences . c , d cv falls with increasing channel count , indicating that although the rmse is held constant the actual field patterns do vary . g , h local sar prediction of afi b1 mapping sequence acquired with power reduction shims comparisons of homogeneity , power requirements and local sar with different numbers of channels when performing rf shimming at a fixed level of homogeneity . unlike fig . 4 , homogeneity values ( rmse / cv ) are predicted rather than measured . a , b rmse is held the same for all configurations ; variability comes from inter - subject differences . c , d cv falls with increasing channel count , indicating that although the rmse is held constant the actual field patterns do vary . g , h local sar prediction of afi b1 mapping sequence acquired with power reduction shims in this study , conducted at 3 t , pronounced areas of b1 inhomogeneity were found in the body with the areas of low b1 intensity following a distinctive diagonal characteristic of elliptic shaped loads , which the human body loosely resembles . our results show that increasing the number of rf channels , and hence the number of effective degrees of freedom , leads to successive improvement in the achievable b1 homogeneity . this is visible from the diagram in fig . 1 , which was generated using one of the datasets included in the study . the solutions found for configurations with more degrees of freedom are nested within those found with fewer degrees of freedom , indicating that a more favourable trade - off between power and inhomogeneity can be achieved by increasing the channel number . a systematic study using multiple volunteers confirmed that increasing the number of channels from one to two , two to four , and four to eight all resulted in statistically significant improvements in homogeneity . improved rf homogeneity also led to a quantifiable improvement in image quality as measured by a blinded evaluation , especially in t1 weighted images . the t2 weighted tse sequence used was found to be more robust to b1 homogeneity . the amplitude of a single spin echo produced by refocusing flip angle is proportional to sin(/2 ) , whereas the pseudo steady - state echo amplitude produced by a tse sequence with multiple refocusing is proportional to sin(/2 ) . for both the t1 and t2 weighted sequences , was 130 , however the former used centric phase encoding , while the latter used linear . as a result it would be expected that the t1 weighted images would be more influenced by the first echo ( proportional to sin(/2 ) ) while the t2 images would be closer to the pseudo steady - state ( sin(/2 ) ) , which is in accordance with the finding that the t2 weighted sequence is more robust to variations in b1 . as well as b1 field homogeneity rf shims were calculated for maximal homogeneity at a fixed rf drive power level , where drive power is the sum of squares of the rf drive levels supplied to each channel , quantified by \|\|rb\|\| . a single station e - field model for a single subject was available for the estimation of peak local sar for these solutions ( fig . these results indicate that there was some reduction in local sar for the shimmed solutions , but importantly none of the shimmed solutions produced a higher local sar than quadrature mode , according to the model . it should be noted that this optimisation did not aim to minimise local sar , and in fact held relative power constant . a second set of experiments which held homogeneity constant and aimed to reduce total power did indeed show consecutive reductions in total power as channel number increased . the local sar , as predicted by the model , also decreased when compared with quadrature mode , but again decreases were erratic . this is partly to be expected because the sar model did not accurately describe the imaging scenarios , either in the positioning or the size and build of the subject . personalised models for each subject might allow a subject - specific estimation of the local sar within the current framework . these could be used to much greater effect by allowing the replacement of the regularization term in eq . 2 with a term based directly on a true sar estimate . a recent study of this type by homann et al . investigated shimming with an 8-channel coil of a similar design to the one used in this study . in that study , it was found that including a subject - specific sar model when determining shim settings produced substantial sar reductions , which is in line with our findings using a single standard model and in relation to total input power . the method employed in the current study , in which an l - curve is calculated to explore balancing b1 homogeneity with total drive power , or ideally with peak local sar , allows flexible choice of operating point . in this study , constant power or constant homogeneity solutions were examined , but in practice any point along the curves could be selected , depending on the situation . as indicated by the imaging examples presented in figs . 2 , 3 , 5 and 6 , different sequences have variable sensitivity to b1 inhomogeneity . the t2w sequence employed here is more robust , and so a lower power solution might be selected to increase efficiency , whereas other parts of an examination may be much more vulnerable and so warrant a different homogeneity - power trade - off . this allows flexible balancing of sar load across a whole examination . at the other extreme , fig . 1 shows that it is possible to achieve highly homogeneous b1 fields over a large ( axial ) field of view with a multi - transmit system at 3 t if the total power is not a concern . however , useful solutions emerge as soon as any power considerations are introduced , in the case of the method used here , by setting to any non - zero value . the lack of suitability of the sar model for the subjects imaged meant that the true sar values were uncertain . for this reason , a conservative approach was taken , and imaging was limited to run at 10 % of the relevant sar limit . this limitation is the subject of a considerable research effort in the wider community : the use of generic models , simplified models generated in real time or even actual in situ measurement of the sar distribution are all current possibilities . more accurate models would allow subject - specific sar reductions to be calculated ; if predictions could be treated with confidence , then reductions in quoted sar would be translatable into an increase in permissible rf duty cycle , which can be used to reduce tr or increase the maximum number of slices within a fixed tr . if the number of slices were increased , extra b1 maps would also need to be acquired , potentially slowing the acquisition process . provide the possibility of rapid b1 measurement over large volumes , alleviating this issue . similarly , while computation times were acceptable for this study , they would not scale well to multiple slices . the code used was , however , not optimized for speed since it was not an issue here , though it could be accelerated if necessary . the human body , with its approximately elliptic cylindrical geometry , produces field variation mainly in the axial plane . as a result , prevailing coil designs consist of elements distributed azimuthally around the magnet , giving maximal axial control . consequently , in this study all imaging and field measurements were obtained in axial planes , where the effects of field inhomogeneity are generally greatest and the existing coil design offers its maximum flexibility in field control . we have found qualitatively similar performance differences between the different channel combinations for coronal orientation scanning . given the asymmetry in the coil design , with its lack of any head - foot segmentation , the manner in which changing the orientation of the scanning plane modulates the magnitude of the effect of the number of degrees of freedom exploited is likely to be strongly influenced by the properties of the coil . a systematic investigation of these effects in the context of an array configuration that has multiple elements arrayed in all three directions around the body will be of further interest and the current work suggests that such additional degrees of freedom would result in a powerful capacity for homogeneity control . similarly , while this study was conducted purely at 3 t , b1 inhomogeneity issues are greater at higher field strengths . the results of this work can not directly be translated to these other scenarios , but they do indicate that transmit arrays , perhaps with more than 8 channels , could mitigate related issues at field strengths greater than 3 t . the impact the number of rf transmit channels has on b1 homogeneity , rf power requirements / sar reduction and image quality when performing subject - specific rf shimming was investigated . increasing the number of transmit channels was found to yield progressive improvements in b1 homogeneity achieved under approximately constant total drive power , or reduction in total drive required to achieve the same level of b1 homogeneity . the regularised shimming approach adopted in this study allows b1 homogeneity and total rf power to be traded against one another and the balance adjusted throughout an examination to optimise imaging performance and control rf power deposition . rf shimming with large coil arrays allows for significant increases in homogeneity , beyond those found with 2-channels . in this study , potentially , further performance increases could be achieved in some anatomies with a greater number of transmit channels , with the use of suitable array coils . Output:	objectat high - field strengths ( 3 t ) inhomogeneity of the radio frequency ( rf ) field and rf power deposition become increasingly problematic . parallel transmission ( ptx)the use of segmented transmission arrays with independently driven elements affords the ability to combat both of these issues . there are a variety of existing designs for ptx coils , ranging from systems with two channels to systems with eight or more . in this work , we have investigated the impact of the number of independent channels on the achievable results for both homogeneity improvement and power reduction in vivo.materials and methodsa 3 t philips achieva mri system fitted with an 8-channel ptx body coil was driven so as to emulate configurations with 1 , 2 4 and 8 independent channels . rf shimming was used in two different anatomies in order to assess improvements in rf homogeneity.resultssignificant homogeneity improvements were observed when increasing from 1 to 2 , 2 to 4 , and 4 to 8 channel configurations . reductions in rf power requirements and local sar were predicted for increasing numbers of channels.conclusionincreasing the number of rf transmit channels adds extra degrees of freedom which can be used to benefit homogeneity improvement or power reduction for body imaging at 3 t .
PubmedSumm118820	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: we analyzed samples from 638 ccrcc patients who had undergone partial or radical nephrectomy at seoul national university hospital in seoul , korea between 1995 and 2005 . all the clinicopathologic data were obtained from medical records , pathology reports and the review of hematoxylin and eosin ( h&e)stained slides . the tumor stage was determined according to the ptnm staging guidline published by the 2010 american joint committee on cancer ( ajcc ) , and nuclear grading was performed based on the fuhrman nuclear grading scale . the recurrence or metastasis of ccrcc confirmation of patients deaths was obtained from medical records or death certificates . following a review of the tumor slides , a representative area from each tumor block was selected and utilized to construct tissue microarrays ( tma ) using a trephine apparatus ( superbiochips laboratories , seoul , korea ) . immunohistochemical staining was performed on 4-m - thick sections taken from the tma slides using the bond - max autostainer ( leica microsystems , bannockburn , il , usa ) . polyclonal rabbit anti - tg2 antibody ( neomarkers , fremont , ca , usa ) was diluted 1:100 . after heat - induced antigen retrieval the binding of the primary antibody was detected using the bond polymer refine detection kit ( leica microsystems ) according to the manufacturer s instructions . tg2 immunoreactivity was classified into four categories according to staining intensity : negative ( 0 ) , weak ( 1 + ) , moderate ( 2 + ) , and strong ( 3 + ) expression . 21 ( ibm co. , armonk , ny , usa ) was used for statistical analysis . the association between clinicopathologic findings and tg expression was analyzed using the linear by linear association . overall survival and cancer - specific survival were analyzed using the kaplan - meier method supported by the logrank test . the overall survival was defined as the time interval from primary radical or partial nephrectomy to last follow - up or patients death . the cancer - specific survival was defined as the time interval from primary radical or partial nephrectomy to last follow - up or cancer - related death and was recorded at final follow - up visit as alive or dead from an unrelated cause . we analyzed samples from 638 ccrcc patients who had undergone partial or radical nephrectomy at seoul national university hospital in seoul , korea between 1995 and 2005 . all the clinicopathologic data were obtained from medical records , pathology reports and the review of hematoxylin and eosin ( h&e)stained slides . the tumor stage was determined according to the ptnm staging guidline published by the 2010 american joint committee on cancer ( ajcc ) , and nuclear grading was performed based on the fuhrman nuclear grading scale . the recurrence or metastasis of ccrcc following a review of the tumor slides , a representative area from each tumor block was selected and utilized to construct tissue microarrays ( tma ) using a trephine apparatus ( superbiochips laboratories , seoul , korea ) . immunohistochemical staining was performed on 4-m - thick sections taken from the tma slides using the bond - max autostainer ( leica microsystems , bannockburn , il , usa ) . polyclonal rabbit anti - tg2 antibody ( neomarkers , fremont , ca , usa ) was diluted 1:100 . after heat - induced antigen retrieval the binding of the primary antibody was detected using the bond polymer refine detection kit ( leica microsystems ) according to the manufacturer s instructions . tg2 immunoreactivity was classified into four categories according to staining intensity : negative ( 0 ) , weak ( 1 + ) , moderate ( 2 + ) , and strong ( 3 + ) expression . ( ibm co. , armonk , ny , usa ) was used for statistical analysis . the association between clinicopathologic findings and tg expression was analyzed using the linear by linear association . overall survival and cancer - specific survival were analyzed using the kaplan - meier method supported by the logrank test . the overall survival was defined as the time interval from primary radical or partial nephrectomy to last follow - up or patients death . the cancer - specific survival was defined as the time interval from primary radical or partial nephrectomy to last follow - up or cancer - related death and was recorded at final follow - up visit as alive or dead from an unrelated cause . the ages of the patient population ranged from 24 to 84 years with a mean age of 56.0 years ( meansd , 56.0211.53 years ) . the measured tumors ranged in size from 0.8 to 22 cm with a mean size of 5.6 cm ( meansd , 5.633.40 cm ) . patient follow - up times ranged from 2 to 223 months with an average follow - up period of 85.7 months ( meansd , 85.7148.46 months ) . at the time of surgery , lymph node metastases were found in 18 cases ( 2.8% ) , and distant metastases were found in 53 cases ( 8.3% ) . four hundred and eight cases were classified as ptnm stage i ( 63.6% ) , 82 as stage ii ( 12.8% ) , 91 as stage iii ( 14.2% ) , and 57 as stage iv ( 8.9% ) . according to fuhrman nuclear grade , 49 cases were classified as grade 1 ( 7.7% ) , 291 as grade 2 ( 45.6% ) , 235 as grade 3 ( 36.8% ) , and 63 as grade 4 ( 9.9% ) . in the non - neoplastic renal parenchyme , , tg2 was diffusely expressed in the cytoplasm of tumor cells in most cases ( positive in 584 ccrccs , 91.5% ) , but the staining intensity was variable . the evaluation of the staining intensity revealed that 54 ( 8.5% ) were negative , 208 showed weak tg2 expression ( 32.6% ) , 322 showed moderate tg2 expression ( 50.5% ) , and 54 ( 8.5% ) showed strong tg2 expression ( fig . 1 ) . the relationship between tg2 expression and pathologic parameters is shown in table 1 . strong tg2 expression was correlated with high fuhrman nuclear grade ( p=.011 ) , high t category ( p=.049 ) , metastasis ( p=.043 ) and male sex ( p<.001 ) but not with n category . overall and cancer - specific survival times were not significantly different between groups showing tg2 staining intensities of 0 , 1 + , and 2 + ( p=.872 and p=.816 , respectively ) . in contrast , the strong ( 3 + ) tg2 expression grouphad significantly shorter overall and cancer specific survival periods compared with groups showing staining intensities 0 , 1 + , or 2 + ( p=.027 and p=.010 , respectively ) ( table 2 , fig . strong tg2 expression was shown to be a marginal independent prognostic indicator of cancer - specific survival for fuhrman nuclear grade and tnm staging ( p=.054 ) . however , these analyses were not statistically significant for overall survival ( p=.154 ) ( table 3 ) . the ages of the patient population ranged from 24 to 84 years with a mean age of 56.0 years ( meansd , 56.0211.53 years ) . the measured tumors ranged in size from 0.8 to 22 cm with a mean size of 5.6 cm ( meansd , 5.633.40 cm ) . patient follow - up times ranged from 2 to 223 months with an average follow - up period of 85.7 months ( meansd , 85.7148.46 months ) . at the time of surgery , lymph node metastases were found in 18 cases ( 2.8% ) , and distant metastases were found in 53 cases ( 8.3% ) . four hundred and eight cases were classified as ptnm stage i ( 63.6% ) , 82 as stage ii ( 12.8% ) , 91 as stage iii ( 14.2% ) , and 57 as stage iv ( 8.9% ) . according to fuhrman nuclear grade , 49 cases were classified as grade 1 ( 7.7% ) , 291 as grade 2 ( 45.6% ) , 235 as grade 3 ( 36.8% ) , and 63 as grade 4 ( 9.9% ) . in the non - neoplastic renal parenchyme , tg2 was faintly expressed , only focally . in ccrcc , tg2 was diffusely expressed in the cytoplasm of tumor cells in most cases ( positive in 584 ccrccs , 91.5% ) , but the staining intensity was variable . the evaluation of the staining intensity revealed that 54 ( 8.5% ) were negative , 208 showed weak tg2 expression ( 32.6% ) , 322 showed moderate tg2 expression ( 50.5% ) , and 54 ( 8.5% ) showed strong tg2 expression ( fig . strong tg2 expression was correlated with high fuhrman nuclear grade ( p=.011 ) , high t category ( p=.049 ) , metastasis ( p=.043 ) and male sex ( p<.001 ) but not with n category . overall and cancer - specific survival times were not significantly different between groups showing tg2 staining intensities of 0 , 1 + , and 2 + ( p=.872 and p=.816 , respectively ) . in contrast , the strong ( 3 + ) tg2 expression grouphad significantly shorter overall and cancer specific survival periods compared with groups showing staining intensities 0 , 1 + , or 2 + ( p=.027 and p=.010 , respectively ) ( table 2 , fig . strong tg2 expression was shown to be a marginal independent prognostic indicator of cancer - specific survival for fuhrman nuclear grade and tnm staging ( p=.054 ) . however , these analyses were not statistically significant for overall survival ( p=.154 ) ( table 3 ) . in this study , we investigated the expression level and clinicopathologic significance of tg2 in ccrcc . strong tg2 expression in ccrcc was associated with high fuhrman nuclear grade , but was not associated with tnm stage . in addition , strong expression of tg2 was associated with significantly worse cancer - specific survival in univariate analysis . a multivariate analysis also showed a marginally significant decrease in cancer - specific survival . to our knowledge , this is the first study to elucidate the prognostic significance of tg2 expression in ccrcc . previous studies using cancer cell lines or nude mice have shown the role of tg2 in cancer cell growth , survival and metastasis . in addition , there have been a few studies showing the clinicopathologic significance of tg2 expression in human cancer tissues . overexpression of tg2 was associated with poor prognosis in ovarian cancer , and high tg2 expression was associated with nodal metastasis and lymphovascular invasion in pancreatic ductal adenocarcinoma . it has also been suggested that tg2 contributes to cancer progression and metastasis by regulating cancer cell migration into the ecm , adhesion to endothelium , invasion , and angiogenesis . a few previous studies have described the relationship between tg2 and the vhl gene , a well - known gene altered in most ccrccs . wykoff et al . showed that tg2 is a novel target gene of vhl in rcc cell lines . in addition to vhl , p53 was also depleted by tg2 in many rcc cell lines a recent study examining microrna expression in rcc demonstrated that mir-1285 , one of the micrornas that are reduced in rcc specimens and cell lines , inhibited cancer cell proliferation , invasion and migration , as well as directly regulating tg2 expression . thus , previous studies indicate that tg2 may play a role in pathogenesis or progression of rcc . however , only few studies examined tg2 expression in human rcc samples . investigated tg2 mrna expression in 95 primary rcc samples and found that tg2 expression alone was not associated with rcc subtype , nuclear grade , t classification or tumor size . another study examined tg2 expression by immunohistochemistry in 70 rcc samples , finding an increased tg2 expression in rcc tissue compared to normal kidney tissue and a significant correlation between increased tg2 expression and high t classification . although these two previous studies showed the significance of tg2 expression in human rcc , in part , they also had some limitations such as relatively small sample sizes and no evaluation of the prognostic significance of tg2 expression . we showed the clinicopathologic significance and prognostic implications of tg2 expression in a large number of ccrccs . the majority of ccrccs showed diffuse tg2 staining , but the staining intensity was variable . only a small subset of ccrccs showed strong tg2 expression ( 54/638 , 6.5% ) that correlated with significantly worse prognosis . the remaining cases showing negative to moderate tg2 expression revealed no significant association of tg2 staining intensity with prognosis . although the precise role of tg2 in the progression of ccrcc is not clear , previous studies have suggested some possible mechanisms . overexpression of tg2 in breast cancer cell lines has been reported to contribute to cancer cell invasion and metastasis through the interaction of tg2 with ecm components such as integrins and fibronectin . in primary rcc samples , increased expression of tg2 , along with 1 integrin and syndecan-4 , was reported to be associated with metastasis . inhibition of tg2 was found to stabilize p53 expression , increasing apoptosis in rcc cell lines . our study also demonstrated that high tg2 expression is associated with tumor aggressiveness such as t category and metastasis . our results are similar to those of previous studies showing an association between tg2 expression and metastasis or tumor stage of rcc first , the study sample was smaller than that of our study ( 70 and 95 in previous studies versus 638 in our study ) . second , they did not separate the rcc subtypes , but we included ccrcc only . in addition our study showed that strong tg2 expression was related to high nuclear grade of ccrcc . this result suggests that tg2 expression might be related to the differentiation of ccrcc . in conclusion , our study is the first to demonstrate the clinicopathologic significance of tg2 expression in a large number of human ccrcc samples . strong tg2 expression was related to tumor aggressiveness , high nuclear grade and poor prognosis . Output:	background : a few recent studies have demonstrated a possible role of transglutaminase 2 ( tg2 ) in tumorigenesis or progression of renal cell carcinoma ( rcc ) . the aim of this study was to examine tg2 expression and its clinicopathologic significance in a large number of human clear cell rccs ( ccrccs).methods : we analyzed 638 ccrcc patients who underwent partial or radical nephrectomy between 1995 and 2005 . the expression of tg2 was determined by immunohistochemistry and categorized into four groups , according to staining intensity : negative ( 0 ) , mild ( 1 + ) , moderate ( 2 + ) , and strong ( 3+).results : tg2 staining intensity was negative in 8.5% of ccrcc ( n=54 ) , 1 + in 32.6% ( n=208 ) , 2 + in 50.5% ( n=322 ) , and 3 + in 8.5% ( n=54 ) . strong tg2 expression was correlated with high fuhrman nuclear grade ( p=.011 ) , high t category ( p=.049 ) , metastasis ( p=.043 ) and male sex ( p<.001 ) but not with n category.the survival analysis showed a significant association between strong tg2 expression and worse overall and cancer - specific survival ( p=.027 and p=.010 , respectively ) . on multivariate analysis , strong tg2 expression was a marginally significant prognostic indicator for fuhrman nuclear grade and tnm staging ( p=.054).conclusions : our study is the first to demonstrate the clinicopathologic significance of tg2 expression in a large number of human ccrcc samples . strong tg2 expression was associated with high nuclear grade and poor prognosis .
PubmedSumm118821	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: in normal somatic human cells , transcription of retrotransposon sequences like l1 and illegitimate recombination involving them are suppressed , restricting their activity to developing germ cells and placental tissues [ 13 ] . suppression of retroelement activity prevents not only retrotransposition , but also various disturbances of transcription by retroelement promoters , interference by retroelement enhancers , the activity of retroelement - encoded enzymes , and illegitimate recombination between homologous elements . moreover , while l1 sequences have the potential to create genomic instability , they probably exert certain beneficial , for instance , silencing of retrotransposons in somatic cells may help to organize the genome into macro- and microdomains with differential transcriptional activity . failure to silence retroelements in cancer cells could therefore permit adverse activities of retroelements as well as perturb any beneficial effects . the present paper summarizes current knowledge about l1 ( line-1 ) retrotransposons in human cancer . for comparison , some observations on human endogenous retroviruses ( herv ) are included . throughout the text , the emphasis will be on identifying open questions , of which there are plenty , as should become evident . since l1 general biology is treated in detail in recent reviews [ 13 ] and other contributions in this issue , only a short introduction will follow here . l1 sequences represent the major class of ltr - less retrotransposons in humans and constitute about 18% of the human genome . while they are interspersed throughout the genome , including euchromatic and heterochromatic regions , they are particularly frequent in gene - poor regions that correspond to chromosomal g - bands . full - length elements are 6 kb in size and contain an internal promoter at the 5-end that generates a genomic transcript which also serves as an mrna . orf1 encodes p40 , an rna - binding protein with cis preference for l1 rna . most are truncated , usually at the 5-end , and mutated , often at many sites . the up to 400 , 000 elements that are still distinctly recognizable as l1 can be categorized into several subclasses . most and perhaps all elements still capable of retrotransposition belong to a subclass named ta . normally , transcriptional activity of l1 is restricted to developing germ cells and to cells of the placenta . in somatic cells , l1 transcription and retrotransposition is prevented by a variety of control mechanisms , including methylation of l1 dna and specifically l1 promoters . in the germline , these mechanisms are relaxed , and retrotransposition does occur occasionally . dangers resulting from l1 reactivation in cancer cells comprise the direct adverse effects of retrotransposition , enhanced illegitimate recombination , and multiple ways of disturbance of transcriptional activity and gene regulation . in the human genome , fewer than 100 l1 elements however , while the danger of retrotransposition is posed only by these intact l1s , other adverse effects can be exerted by a larger number of elements . in addition , reactivation may interfere with potential effects of l1 sequences such as their contribution to the global and local organization of the genome and the provision of gene regulatory sequences . the mechanisms involved in l1 retrotransposition are now quite well understood [ 13 ] . orf2 induces single - strand breaks at at - rich dna target regions , preferably at consensus tttt / a sites . following l1 orf2 endonuclease action , the l1 rna poly - a sequence pairs with oligo - dt sequences in the target dna , which serve as primers for reverse transcription by the l1 orf2 encoded enzyme . reverse transcription yields a branched dna structure , which is presumably resolved by cellular dna repair systems . the retrotransposition mechanism thus requires at least one recombination and creates two dna single - strand breaks close to each other , which can in effect behave like a double - strand break . therefore , attempted or successful retrotranspositions carry a high risk of eliciting chromosome breaks , deletions , translocations , and recombinations . moreover , successful retrotransposition events are likely to change the activity of genes at the insertion site . diverse outcomes of insertions are conceivable , including increased or decreased transcriptional activity and the generation of novel , variant transcripts ( figure 1 ) . on a genome - wide scale , the effects of retrotranspositions might be mitigated by the propensity of l1 elements to insert into at - rich , gene - poor regions of the genome , and especially into or close to other elements . however , even retrotranspositions outside transcriptional units can have catastrophic effects on a cell by inducing dna strand breaks and initiating a breakage - fusion - bridge cycles . effects on transcription theoretically , a wide range of effects on the transcription of host genes can be exerted by l1 regulatory elements and transcriptional sequences that are located close to or within them ( figure 1 ) . the l1 promoter is moderately strong [ 8 , 9 ] and the polyadenylation signal is relatively weak permitting a substantial amount of read - through [ 10 , 11 ] . therefore , active l1 promoters located in sense orientation 5 to a gene could override the normal transcriptional controls of a gene to deregulate expression . active l1 promoters located in sense orientation within the transcriptional unit could generate alternative 5-truncated transcripts . indeed , many regulatory elements of human genes are derived from l1 or herv sequences . a prominent example is syncytin1 , a crucial protein required for the formation of syncytic cells in the placenta which has evolved from an herv env protein . the gene encoding syncytin1 is now consequently named ervwe1 for endogenous retrovirus w envelope protein1 . as in this case , regulatory sequences derived from l1 or herv sequences are often more active during germ cell or embryonic development than in somatic cells . in cancer cells , decreased methylation and a more open chromatin structure of such sequences could therefore allow the reexpression of genes or transcripts that are normally restricted to germ cells or the embryo , that is , oncofetal or cancer - testis gene expression . alternative transcripts may also be generated by the use of polyadenylation sites of intragenic l1 sequences , especially if these are 5-truncated . it is not known which mechanism ensures that they are normally ignored in elements located within a transcriptional unit . consequently , it is difficult to estimate how altered methylation and chromatin structure in cancer cells would affect their recognition . retroelements oriented in opposite direction inside a transcriptional unit might interfere with transcription by antisense effects , most prominently through formation of dsrna . this mechanism is implicated in the generation of heterochromatin in some organisms [ 14 , 15 ] . in mammalian cells , dsrna ought to induce general cellular antiviral defense mechanisms , for example , by activating pkr , or leads to the production of sirnas and gene - specific downregulation . interestingly , transcripts containing alu sequences in sense direction appear to be edited and consequently destabilized in human cells [ 1618 ] . it is possible that a similar process acts on l1 sequences , but it is currently unknown to what extent intact or partial l1 sequences in pre - mrna are edited and whether such sequences are employed for posttranscriptional gene regulation , in normal or in cancer cells . a recent study suggests that l1 rnas are not edited , at least not by the usual apobec3 g cytidine deaminase . a further possibility has been suggested by the recent discovery of an antisense promoter near the 5-end of intact l1 sequences . when active , this promoter could exert several effects on cellular genes , depending on its orientation . if located in sense direction , antisense transcripts could lead to downregulation ; if located in antisense direction , it might lead to overexpression of normal transcripts or the emergence of novel transcripts . accordingly , demethylation of l1 sequences in cancer cells may not only activate their canonical sense , but also their antisense promoters . orf1 encodes a p40 rna - binding protein supposed to act as a chaperone and transport factor for l1 rna . the properties of these enzymes have meanwhile been studied quite well in vitro [ 2224 ] , but their impact on normal and cancer cells remains difficult to estimate . one open question is how many l1 elements are actually capable of expressing active proteins , especially , whether only intact elements form the source . it is thought that less than 100 l1 sequences are capable of retrotransposition which all belong to the ta family . they are the most likely source of reverse transcriptase , endonuclease , and p40 protein in germ cells and the embryo as well as in cancer cells . however , many elements of other families are also intact , except for missense and stop mutations . they could still give rise to one or the other intact protein , as well as variant proteins . alu retrotransposition uses the enzymatic machinery provided by l1 and is therefore dependent on expression of l1 proteins [ 26 , 27 ] . similarly , complementation of transposition in trans among l1 sequences is inefficient , but not impossible , that is , full - length l1s with mutated protein - coding sequences might still be capable of retrotransposition , if proteins are supplemented by other elements . the proteins provided by l1s are also most likely involved in the formation of pseudogenes . it is unknown , however , whether their endogenous expression levels in cancer cells are sufficient to support retrotransposition . importantly , the potential danger of proteins encoded by l1s depends critically on their ability to exert effects beyond aiding retrotransposition in cis or in trans . in the context of cancer , the endonuclease introduces single - strand breaks ( nicks ) into dna with moderately stringent specificity . the ultimate result of single - strand breaks introduced by the endonuclease in a cell depends on several factors . nicks in s - phase are most problematic , because they can be converted into double - strand breaks by the replication complex . dna repair competence and capacity constitute a second factor that may differ between normal and cancer cells . thirdly , the presence of l1 rna and other proteins at the nicked site would be thought to influence the type and efficiency of repair . the potential impact of l1 reverse transcriptase and rna - binding protein similarly depend on their specificity , actually in two respects . first , to which extent are they specific for l1 ( and alu ) sequences ? second , are reverse transcription and rna - chaperoning their sole activities ? drug inhibitors of reverse transcriptase and , more specifically , sirna directed against l1 rt decrease the proliferation of cancer cell lines . such effects are difficult to explain by the known function of the enzyme in mediating l1 and alu retrotranspositions . illegitimate recombination successful and abortive retrotransposition can create chromosomal instability and initiate illegitimate recombination by inducing dna strand breaks and by generating a branched dna structure . however , even in the absence of retrotransposition , the presence of thousands of intact , rather long ( 6 kb ) , and relatively homologous sequences in the genome plus the presence of ten thousands of truncated and mutated sequences carries a permanent risk of illegitimate recombination between elements located at different sites . in the germline , recombination between different l1 elements contributes to human evolution , but also elicits inherited diseases . in somatic cells , recombination ought to be restricted strictly to homologous recombination repair of dna double - strand breaks using homologous sequences from sister chromatids or at most from the homologous chromosome . it is generally assumed that recombination between l1 sequences in somatic cells is suppressed by dense dna methylation and tight packaging into chromatin . decreased methylation and relaxed chromatin structure of l1 sequences in cancer cells might therefore facilitate illegitimate recombination contributing to chromosomal instability . disturbance of normal genome organization l1 sequences are thought to be involved in the organization of the human genome , their presence influencing short - range and long - range chromatin structures . l1 sequences are overrepresented in the late - replicating g - bands of human chromosomes . it is plausible that their presence is responsible for their more heterochromatic character . l1s are also overrepresented on the x - chromosome where they may act as way stations during x - chromosome inactivation [ 32 , 33 ] . in a similar fashion , methylated l1 sequences on other chromosomes which are packaged into hypermethylated and deacetylated chromatin may constitute the cores of localized facultative heterochromatic regions . intriguingly , some l1 sequences are associated with nuclear matrix attachment regions and may contribute to the organization of chromatin loops . l1 clusters located between genes may furthermore contribute to the segmentation of the genome into transcriptional units , helping to prevent interference by regulatory elements from neighboring genes ( figure 2 ) . function would explain why hox clusters , which require long - range interactions for their proper expression pattern , are largely devoid of retroelement sequences . importantly , the organization of the genome into subregions and loops pertains not only to transcription , but also to replication and imposes restrictions on the extent of dna repair and recombination . accordingly , alterations of dna methylation and chromatin structure at l1 sequences in cancer cells could have effects not only on transcription , but also on dna replication timing and on the extents of recombination and dna repair . deregulation of gene expression could not only be caused by activation of l1 elements , but also through altered chromatin structure at inactive l1s allowing transcriptional interference by neighboring enhancers or silencers . not only in this particular situation dna replication patterns could be disturbed , with normally late - replicating dna shifting towards earlier periods within s - phase . barrier functions of repeat dna in the genome could be alleviated , allowing dna processing during repair and holiday junctions formed during recombination to pass through stretches of dna that are less accessible in normal cells . effects on cell stress and immune responses endogenous retroelements have been implicated in the regulation of cell stress responses , of the immune system , and in the pathogenesis of several human autoimmune diseases . the strongest data on regulation of human retroelements by cell stress concern alu sequences . likewise , the most convincing data on regulation of the immune system by retroelements and on the involvement in autoimmune diseases implicates hervs . there are , however , indications that l1 sequences too are induced during stress responses , during cytotoxic chemotherapy , and by uv exposure of skin cells . furthermore , l1 sequences may act in a similar fashion as hervs in at least one autoimmune disease , rheumatoid arthritis . in this disease , synovial fibroblasts become aberrantly activated in a fashion that resembles in many respects fibroblast activation in the stroma of malignant tumors , with enhanced proliferation , migration , and secretion of cytokines , chemokines , and proteases . the fibroblast genomes at large and l1 promoters in particular were found to become hypomethylated . overexpression of the p40 orf1 protein in this disease has been suggested to activate stress - induced protein kinases . it is thought that l1 hypomethylation and expression provide an amplification step in the pathogenesis of the disease by enhancing immune responses . the function of the activation of retroelements during cellular stress responses is poorly understood . conceivably , it forms part of a signaling system that alerts the immune system to the presence of infected or altered cells . if that proposition is true , hypomethylation and activation of l1 sequences in cancer cells are likely to influence the immune response to malignant tumors . in support of this idea , some herv proteins have been found to behave as tumor antigens [ 44 , 45 ] , but it is not known whether proteins encoded by l1 do so too . a similarly open question is to which extent hypomethylated repeat dna liberated from tumor cells elicits danger signals in cells regulating the immune response . interestingly , l1 activation is considered as a cause of increased plasma dna levels in tumor patients . many of the effects that can be envisioned to be exerted by activated l1 retrotransposons have indeed been observed in the human germline and during fetal development [ 13 , 47 , 48 ] . in cancer cells , retroelement dna sequences become hypomethylated , transcripts as well as protein products can be detected , and l1 sequences are located at sites of breakage and recombination . for l1 retrotransposons , data on l1 expression are scarce , in contrast to several reports on the expression of herv gene products . l1 sequences have been found at or near deletion ends and translocation breakpoints , but the precise frequency and the mechanisms involved remain to be determined . intriguingly , actual retrotransposition events are exceptional . in a large number of human cancers , decreased methylation of l1 sequences has been documented ( table 1 ) . this decrease occurs in the context of general alterations in dna methylation patterns that accompany carcinogenesis in many human tissues . these are regarded as part of an important epigenetic mechanism driving cancer development and progression . alterations of methylation in cancer cells comprise hypermethylation which occurs focally and in a largely specific fashion , typically at cpg islands surrounding the transcriptional start regions of individual genes . somewhat paradoxically , in many , but not all cancers , increased methylation at specific sites is found alongside a decrease in methylation levels of the overall genome . the decrease in methylation appears to be relatively unspecific and is therefore commonly designated as genome - wide or global hypomethylation [ 64 , 65 ] . in normal somatic cells , the bulk of methylcytosine is found in repetitive sequences such as l1 , hervs , and alus , but also at cpg - rich satellites such as sat2 and sat3 . the overall decrease in methylation found in cancer cells therefore reflects a largely parallel decrease in the methylation of retrotransposon sequences . as a rule , however , hypomethylation of l1 sequences has traditionally been investigated by southern blot analysis following digestion of dna with methylation - sensitive restriction enzymes . recently , methods employing pcr following bisulfite treatment of dna have been developed for this purpose [ 52 , 66 ] . these techniques are promising , since they can also be applied to small amounts of suboptimal quality dna . however , because of the heterogeneity of l1 sequences , the extent of their demethylation is difficult to estimate precisely , especially by pcr - based methods . southern blot analyses suggest that in cancer cell lines up to 70%80% of cpg sites in l1 sequences become demethylated . accordingly , individual herv proviruses are essentially unmethylated in cancer cell lines with strong hypomethylation . nevertheless , l1 hypomethylation is anything but uniform in different cancers , in two respects . first , different extents of hypomethylation are found in cancers of the same type . these differences are also observed in cancer cell lines and are therefore not explained by differences in the proportion of tumor cells in tissue samples . second , l1 hypomethylation appears to develop at different stages in the development of different cancers . for instance , it is found at early stages of colon and bladder cancers [ 53 , 60 ] , but only in higher - stage prostate carcinomas [ 55 , 56 ] while primary renal carcinomas lack significant line-1 hypomethylation [ 52 , 53 ] . germ cell cancers are a special case since they have generally hypomethylated genomes , presumably due to their origin from cells with lower methylation levels [ 67 , 68 ] . accordingly , l1 [ 51 , 69 ] and herv sequences are strongly hypomethylated in testicular cancers . finally , note that very little is known on the methylation of individual l1 sequences , and accordingly , whether their hypomethylation in cancers is uniform . although genome - wide hypomethylation in human cancers has been known for more than twenty years , the mechanisms eliciting this alteration are still unknown . hypothetical mechanisms include insufficient levels of methyl group donors , ultimately of s - adenosylmethionine , inadequate expression or regulation of dna methyltransferases , reexpression of dna demethylases , and altered expression of chromatin regulators directing dna methyltransferases [ 64 , 65 ] . retroelements constitute approximately 45% of the human genome and contain an at least proportionate amount of methylcytosine . moreover , they appear to be preferentially recognized by the dna methylation machinery and at least in some circumstances appear to act as centers of methylation from which methylation spreads into adjacent sequences . therefore , genome - wide hypomethylation could theoretically arise as a consequence of a defect in the recognition of retroelements as methylation targets . unfortunately , it is still not known how retroelements are distinguished for silencing in mammalian genomes . therefore , l1 silencing in somatic cells can not be simply a consequence of transcriptional inactivity . instead , silencing must have been actively established during fetal development and is faithfully maintained through cell proliferation and differentiation in normal somatic cells . dna methylation of retroelements is established first during germ cell development and then again during gastrulation , when the genome at large becomes de novo methylated , except for sequences that are actively protected , such as cpg islands and active imprinted genes . de novo methylation in the mouse embryo requires dna methyltransferases , specifically dnmt3a and dnmt3b as well as dnmt1 for maintenance of the established methylation [ 74 , 75 ] . in male germ cells it is not entirely clear whether methylation of l1 during development requires specific chromatin regulators directing the methyltransferases . one candidate is smarca6 , as its mouse orthologue lsh has been found to be required for proper methylation of l1 sequences . inactivation of lsh in mice causes l1 hypomethylation , but only limited disturbances of the methylation of single - copy genes . in comparison , inactivation of another chromatin protein atrx causes hypomethylation of rdna , but leaves l1 methylation intact . this suggests that the specificity of dna methylation may be regulated by specific chromatin regulator proteins . a variety of chromatin regulator proteins have been reported to be aberrantly expressed or even mutated in human cancers [ 65 , 79 81 ] . however , many of these changes are rare or are specific to particular cancers . it is therefore difficult to envision a change in a single master regulator of l1 methylation as the cause of the widely distributed hypomethylation of these sequences . more likely , l1 hypomethylation could be associated with the general reorganization of chromatin structure in aneuploid cancer cells that disturbs the compartmentation of the genome [ 65 , 79 , 80 ] . genome - wide alterations in histone modification have recently been described in cancer cells [ 82 , 83 ] . given the high proportion of l1 sequences in the human genome , these are likely to affect these retrotransposons and to interact with their methylation . note that the relation between dna methylation and histone modifications at l1 sequences is far from being understood . l1 expression in cancers the mechanisms underlying hypomethylation changes in human cancers are not understood , but even the description of these changes is fragmentary . for instance , methylation of hervs has been studied in only a few cancers . available data suggest that they are affected by genome - wide hypomethylation in parallel to line-1 sequences ( table 1 ) . in selected cancers , endogenous retroviral sequences expressed sequences derived from hervs are found in germ cell cancers and antibodies directed against herv - encoded proteins are found in the blood of patients . in cancers of somatic cell origin , bona fide transcripts for envelope and auxiliary proteins have been reported , especially in breast cancer [ 44 , 85 ] , and recently in melanoma . some results suggest that herv expression occurs in a wider range of cancers and even normal tissues [ 87 , 88 ] . these data need further verification to exclude artifacts from genomic dna and unspliced transcripts . moreover , the somewhat surprising findings that different transcripts from different subfamilies may be expressed in a cancer - type - specific fashion call for a closer analysis of the mechanisms involved the available data suggest that expression of full - length l1 sequences is by far the strongest in teratocarcinomas , while weaker expression is observed in a wider range of carcinomas exhibiting hypomethylation . this expression pattern therefore resembles that of hervs . since hervs also give rise to spliced transcripts , rna analyses can provide a first indication of which protein products are expressed . for l1 so far , no definite data have been published on the expression of the proteins encoded by the retrotransposons in human cancer . their presence in germ cell cancers and teratocarcinoma cell lines , however , is very likely . involvement of l1 in chromosome breakage and recombination whereas retrotransposition events take place quite regularly in the germline , at an estimated rate of 1 event per 100 births [ 3 , 4 ] , very few have been reported in cancer cells [ 90 , 91 ] . similarly , although l1 sequences have been shown to become incorporated at sites of double - strand break dna repair in model experiments , according sequence changes have only exceptionally been observed in human cancers . in spite of the caveats discussed below , it is therefore probably safe to conclude that actual retrotransposition events are rare in human cancers and do not regularly contribute to genomic instability . the evidence is better for indirect mechanisms by which retrotransposons could promote chromosomal instability in human cancer . l1 hypomethylation and chromosomal instability correlate well with each other in several cancer types [ 55 , 58,94 ] . a similar relationship has been observed between the hypomethylation of tandem satellite sequences and alterations of the chromosomes that carry them as large juxtacentromeric region [ 9597 ] . in this case , hypomethylation of the satellite sequences is thought to cause decondensation of pericentromeric chromatin and an increased propensity for chromosomal breaks and rearrangements in this region . in a similar fashion , hypomethylation of retroelement sequences dispersed in the genome could facilitate illegitimate recombination . in favor of this idea , l1 sequences are enriched at the ends of 3p14.1 and 9p21 deletions in carcinomas [ 36 , 98 , 99 ] and homozygous deletions arise preferentially in chromosomal regions with high line content . it has also been suggested that l1 and herv sequences are involved in the formation of double - minute circular chromosomes in cancer cells [ 101 , 102 ] . the most straightforward hypothesis accounting for these findings is that decreased methylation and presumably more open chromatin structure at l1 sequences in cancer cells favors the illegitimate recombination between elements at different genomic locations , for example , during homologous recombination repair of dna strand breaks . however , closer analyses of the deletion ends in solid tumors indicate that this hypothesis is probably incorrect . while deletion ends are indeed often located in or near l1 sequences and particularly l1 clusters , the breakpoints invariably show hallmarks of dna double - strand break repair by nonhomologous end - joining ( nhej ) . typically , one end of the deletion is located in or close to an l1 sequence , while the other end is provided by an unrelated single copy or repeat sequence [ 36 , 99 , 103 ] . such structures also appeared as occasional end products of repair of dna double - strand breaks induced by a restriction endonuclease at a specific chromosomal site . a plausible explanation for this structure is that processing by the nhe1 protein complex damaged dna ends is slowed down at l1 sequences by denser chromatin , favoring reannealing and ligation there . if this explanation is correct , retroelement hypomethylation in cancer could paradoxically diminish the tendency of breakpoints to be located at l1 sequences . it would instead tend to increase the size of deleted and recombinated sequences , because dna processing and holiday junctions arising during recombination repair could move further through more open chromatin . first of all , far too few chromosomal breakpoints have been investigated , especially in carcinomas . secondly , it has not been established for any chromosomal alteration whether hypomethylation of repeat sequences at the affected site preceded it . they might be associated with local structures that are particularly prone to breakage , such as fragile sites or the anchorage sites of chromatin loops . retrotranspositions in the germline take place at a significant rate of approximately 1 event per 100 births . in addition , a substantial number of recombination events involving l1 elements have been detected , typically because they elicited translocations or rearrangements causing inherited diseases [ 2 , 47 , 48 ] . specifically , l1 retrotransposition and illegitimate recombination in the germline are causes of inherited and congenital cancers . for instance , a germline deletion in the mlh1 gene carries hallmarks of recombination initiated by a failed l1 retrotransposition event . in contrast , in spite of considerable evidence hinting at a reactivation of l1 retrotransposons in a variety of human cancers , there is limiting evidence for major consequences of this process . one is technical : even typical effects expected from l1 reactivation are difficult to detect by the techniques commonly used to investigate genetic alterations in human cancers . the other is biological : reactivation may be partial and the mechanisms ensuring silencing of l1 dna sequences and limiting the effects of transcribed sequences may remain functional to some degree . perhaps , limited reactivation of l1 sequences may exert effects more through the loss of symbiotic functions than through direct adverse effects on genomic stability . this possibility is even more difficult to ascertain . in general , investigations of genetic and epigenetic changes in human cancers avoid dealing with repeat sequences and focus on single - copy protein - coding genes . mutation analysis of genes is typically restricted to coding sequences and employs pcr techniques to analyze individual exons or mrna . insertions or recombinations caused by l1 or other retroelements would often not be detected by this approach , unless they occur within exons . therefore , it might not be coincidental that reports describing oncogene activation and tumor suppressor inactivation by l1 insertion date from a period when southern blot analysis was more en vogue . similarly , recombination and deletions in cancers are well documented at the level accessible by cytogenetic techniques , but are not well investigated at the molecular level , with the important exception of translocations in hematological cancers . in these , retroelements have indeed been found at many translocation sites , although their role in the generation of the translocations is not clear . in contrast , very few studies have addressed the precise structure of chromosomal breakpoints in solid tumors . a recent genome - wide study of 505 cancer cell lines yielded a strong association between line content and the presence of homozygous deletions , but no breakpoints were characterized in detail . detailed analyses of deletion endpoints at the fra3b fragile site and around cdkn2a at 9p21 revealed a preponderance of l1 sequences at or close to the deletion endpoints . such analyses remain tedious even with the finished human genome sequence having become available . therefore , we know little on the structure of amplicons , another category of unstable sequence in cancer cells , and next to nothing on the sites of illegitimate recombination in cancer cells . l1 sequences have been detected in double minutes , an important intermediate in one amplification mechanism , and have been proposed , but not proven to be involved in their formation . by a comparison of loss of heterozygosity analysis and cytogenetic techniques of chromosome 8p in bladder cancer cell lines , recombination events were recently shown to be much more frequent and were shown to take place across much smaller regions than hitherto assumed . however , it is not known and difficult to determine what initiated the recombination events and which sequences precisely were involved . in summary , therefore , whereas it seems unlikely that retrotransposition is common in human cancer cells , the role of l1s in recombination and chromosome breakage is probably underestimated due to a lack of studies with appropriate methodology . a similar argument can be made for epigenetic effects of l1 sequences in cancer . in genome - wide screens for altered methylation in cancer , repeat sequences are often and understandably considered a nuisance and typically removed by prehybridization . overall changes in l1 methylation are therefore well documented , but data on the behavior of individual sequences is lacking . bisulfite sequencing is restricted to a few hundred bp per pcr and is prone to artifacts from template switching and target priming when applied to repeat sequences . this method has revealed that in fetal fibroblasts , the promoters of most full - length l1 sequences are densely and symmetrically methylated , while selected elements are unmethylated . accordingly , it is not clear whether the number of completely unmethylated elements increases in cancer cells or whether the decrease in methylation is distributed across all l1 sequences . these questions extend of course to the issue of chromatin structure at l1 elements . the contribution of l1s to altered gene expression in cancer perhaps most striking are reports on frequent downregulation of genes ( usually tumor suppressor candidates ) without detectable genetic alterations in their vicinity and altered dna methylation in regulatory sequences . recently , increased expression of mirna has been introduced as a potential cause of such enigmatic observations . in the light of potential effects of l1 sequences , perhaps effects exerted by l1 elements in or near affected genes again , this is a highly difficult issue , especially if genes that are investigated are alternatively spliced even in normal cells . the argument can be broadened further to encompass the potential boundary function of repeat elements . its disturbance by altered chromatin structure in cancer cells may result in more or less subtle up- and downregulation . more than two decades of intense work have been spent on a small number of selected loci to understand the mechanisms of action of long - range regulatory elements and boundary elements at all . it is understandable that very little is known on how they are altered in cancer cells . still , it may be advisable to consider such effects and others mentioned in this paragraph when encountering instances of altered gene regulation in cancer that can not be straightforwardly explained by mutations or altered dna methylation of gene regulatory sequences . the difficulties in determining the impact of l1 sequences in cancer cells resulting from methodological limitations are compounded by biological factors . it is likely that this restriction of transcriptional activity is aided by an inactive chromatin structure , although this can not be considered proven . a second set of l1 controls appears to act at the rna level , perhaps exerted by cytidine deaminases , leading to rna instability . alu - containing rnas are subject to editing [ 1618 ] , but the evidence for l1 rna is scanty . active tp53 prevents retrotransposition , but this is very likely not the only barrier at this step . last and perhaps not least , there is some evidence that retroelement activation might attract immune responses . as discussed elsewhere in detail , such responses are better documented for hervs , but they might additionally or concurrently select against cells with strongly activated l1 retrotransposons outside immunoprivileged organs . there is good evidence for three of these protective mechanisms to be impeded in cancer cells : dna methylation is decreased , tp53 and checkpoints are often defective , and immune responses to advanced cancers are muted . we know very little about another mechanism , control of retroelements at the rna level . in summary , therefore , the regulation of l1 genomic structure , expression , and retrotransposition is clearly perturbed in many human cancers , but inactivation of all tiers of control may be rare . some cancer types exhibit few changes , for example , renal cell carcinoma , where even l1 dna methylation appears to be maintained , while germ cell cancers appear to represent the other end of the spectrum [ 49 , 50 , 52 , 53 ] . even in these , however , retrotransposition events appear to be rare and the evidence for major contributions of retrotransposon activity to the cancer phenotype is limited . a likely candidate is tp53 , since germ cell tumors are among the few cancer types in which mutations of this tumor suppressor are rare . dangers resulting from l1 reactivation in cancer cells comprise the direct adverse effects of retrotransposition , enhanced illegitimate recombination , and multiple ways of disturbance of transcriptional activity and gene regulation . in the human genome , fewer than 100 l1 elements however , while the danger of retrotransposition is posed only by these intact l1s , other adverse effects can be exerted by a larger number of elements . in addition effects of l1 sequences such as their contribution to the global and local organization of the genome and the provision of gene regulatory sequences . the mechanisms involved in l1 retrotransposition are now quite well understood [ 13 ] . orf2 induces single - strand breaks at at - rich dna target regions , preferably at consensus tttt / a sites . following l1 orf2 endonuclease action , the l1 rna poly - a sequence pairs with oligo - dt sequences in the target dna , which serve as primers for reverse transcription by the l1 orf2 encoded enzyme . reverse transcription yields a branched dna structure , which is presumably resolved by cellular dna repair systems . the retrotransposition mechanism thus requires at least one recombination and creates two dna single - strand breaks close to each other , which can in effect behave like a double - strand break . therefore , attempted or successful retrotranspositions carry a high risk of eliciting chromosome breaks , deletions , translocations , and recombinations . moreover , successful retrotransposition events are likely to change the activity of genes at the insertion site . diverse outcomes of insertions are conceivable , including increased or decreased transcriptional activity and the generation of novel , variant transcripts ( figure 1 ) . on a genome - wide scale , the effects of retrotranspositions might be mitigated by the propensity of l1 elements to insert into at - rich , gene - poor regions of the genome , and especially into or close to other elements . however , even retrotranspositions outside transcriptional units can have catastrophic effects on a cell by inducing dna strand breaks and initiating a breakage - fusion - bridge cycles . effects on transcription theoretically , a wide range of effects on the transcription of host genes can be exerted by l1 regulatory elements and transcriptional sequences that are located close to or within them ( figure 1 ) . the l1 promoter is moderately strong [ 8 , 9 ] and the polyadenylation signal is relatively weak permitting a substantial amount of read - through [ 10 , 11 ] . therefore , active l1 promoters located in sense orientation 5 to a gene could override the normal transcriptional controls of a gene to deregulate expression . active l1 promoters located in sense orientation within the transcriptional unit could generate alternative 5-truncated transcripts . indeed , many regulatory elements of human genes are derived from l1 or herv sequences . a prominent example is syncytin1 , a crucial protein required for the formation of syncytic cells in the placenta which has evolved from an herv env protein . the gene encoding syncytin1 is now consequently named ervwe1 for endogenous retrovirus w envelope protein1 . as in this case , regulatory sequences derived from l1 or herv sequences are often more active during germ cell or embryonic development than in somatic cells . in cancer cells , decreased methylation and a more open chromatin structure of such sequences could therefore allow the reexpression of genes or transcripts that are normally restricted to germ cells or the embryo , that is , oncofetal or cancer - testis gene expression . alternative transcripts may also be generated by the use of polyadenylation sites of intragenic l1 sequences , especially if these are 5-truncated . it is not known which mechanism ensures that they are normally ignored in elements located within a transcriptional unit . consequently , it is difficult to estimate how altered methylation and chromatin structure in cancer cells would affect their recognition . retroelements oriented in opposite direction inside a transcriptional unit might interfere with transcription by antisense effects , most prominently through formation of dsrna . this mechanism is implicated in the generation of heterochromatin in some organisms [ 14 , 15 ] . in mammalian cells , dsrna ought to induce general cellular antiviral defense mechanisms , for example , by activating pkr , or leads to the production of sirnas and gene - specific downregulation . interestingly , transcripts containing alu sequences in sense direction appear to be edited and consequently destabilized in human cells [ 1618 ] . it is possible that a similar process acts on l1 sequences , but it is currently unknown to what extent intact or partial l1 sequences in pre - mrna are edited and whether such sequences are employed for posttranscriptional gene regulation , in normal or in cancer cells . a recent study suggests that l1 rnas are not edited , at least not by the usual apobec3 g cytidine deaminase . a further possibility has been suggested by the recent discovery of an antisense promoter near the 5-end of intact l1 sequences . when active , this promoter could exert several effects on cellular genes , depending on its orientation . if located in sense direction , antisense transcripts could lead to downregulation ; if located in antisense direction , it might lead to overexpression of normal transcripts or the emergence of novel transcripts . accordingly , demethylation of l1 sequences in cancer cells may not only activate their canonical sense , but also their antisense promoters . orf1 encodes a p40 rna - binding protein supposed to act as a chaperone and transport factor for l1 rna . the properties of these enzymes have meanwhile been studied quite well in vitro [ 2224 ] , but their impact on normal and cancer cells remains difficult to estimate . one open question is how many l1 elements are actually capable of expressing active proteins , especially , whether only intact elements form the source . it is thought that less than 100 l1 sequences are capable of retrotransposition which all belong to the ta family . they are the most likely source of reverse transcriptase , endonuclease , and p40 protein in germ cells and the embryo as well as in cancer cells . however , many elements of other families are also intact , except for missense and stop mutations . they could still give rise to one or the other intact protein , as well as variant proteins . alu retrotransposition uses the enzymatic machinery provided by l1 and is therefore dependent on expression of l1 proteins [ 26 , 27 ] . similarly , complementation of transposition in trans among l1 sequences is inefficient , but not impossible , that is , full - length l1s with mutated protein - coding sequences might still be capable of retrotransposition , if proteins are supplemented by other elements . the proteins provided by l1s are also most likely involved in the formation of pseudogenes . it is unknown , however , whether their endogenous expression levels in cancer cells are sufficient to support retrotransposition . importantly , the potential danger of proteins encoded by l1s depends critically on their ability to exert effects beyond aiding retrotransposition in cis or in trans . in the context of cancer , the endonuclease introduces single - strand breaks ( nicks ) into dna with moderately stringent specificity . the ultimate result of single - strand breaks introduced by the endonuclease in a cell depends on several factors . nicks in s - phase are most problematic , because they can be converted into double - strand breaks by the replication complex . dna repair competence and capacity constitute a second factor that may differ between normal and cancer cells . thirdly , the presence of l1 rna and other proteins at the nicked site would be thought to influence the type and efficiency of repair . the potential impact of l1 reverse transcriptase and rna - binding protein similarly depend on their specificity , actually in two respects . first , to which extent are they specific for l1 ( and alu ) sequences ? second , are reverse transcription and rna - chaperoning their sole activities ? drug inhibitors of reverse transcriptase and , more specifically , sirna directed against l1 rt decrease the proliferation of cancer cell lines . such effects are difficult to explain by the known function of the enzyme in mediating l1 and alu retrotranspositions . illegitimate recombination successful and abortive retrotransposition can create chromosomal instability and initiate illegitimate recombination by inducing dna strand breaks and by generating a branched dna structure . however , even in the absence of retrotransposition , the presence of thousands of intact , rather long ( 6 kb ) , and relatively homologous sequences in the genome plus the presence of ten thousands of truncated and mutated sequences carries a permanent risk of illegitimate recombination between elements located at different sites . in the germline , recombination between different l1 elements contributes to human evolution , but also elicits inherited diseases . in somatic cells , recombination ought to be restricted strictly to homologous recombination repair of dna double - strand breaks using homologous sequences from sister chromatids or at most from the homologous chromosome . it is generally assumed that recombination between l1 sequences in somatic cells is suppressed by dense dna methylation and tight packaging into chromatin . decreased methylation and relaxed chromatin structure of l1 sequences in cancer cells might therefore facilitate illegitimate recombination contributing to chromosomal instability . disturbance of normal genome organization l1 sequences are thought to be involved in the organization of the human genome , their presence influencing short - range and long - range chromatin structures . l1 sequences are overrepresented in the late - replicating g - bands of human chromosomes . it is plausible that their presence is responsible for their more heterochromatic character . l1s are also overrepresented on the x - chromosome where they may act as way stations during x - chromosome inactivation [ 32 , 33 ] . in a similar fashion , methylated l1 sequences on other chromosomes which are packaged into hypermethylated and deacetylated chromatin may constitute the cores of localized facultative heterochromatic regions . intriguingly , some l1 sequences are associated with nuclear matrix attachment regions and may contribute to the organization of chromatin loops . l1 clusters located between genes may furthermore contribute to the segmentation of the genome into transcriptional units , helping to prevent interference by regulatory elements from neighboring genes ( figure 2 ) . such a boundary function would explain why hox clusters , which require long - range interactions for their proper expression pattern , are largely devoid of retroelement sequences . importantly , the organization of the genome into subregions and loops pertains not only to transcription , but also to replication and imposes restrictions on the extent of dna repair and recombination . accordingly , alterations of dna methylation and chromatin structure at l1 sequences in cancer cells could have effects not only on transcription , but also on dna replication timing and on the extents of recombination and dna repair . deregulation of gene expression could not only be caused by activation of l1 elements , but also through altered chromatin structure at inactive l1s allowing transcriptional interference by neighboring enhancers or silencers . not only in this particular situation dna replication patterns could be disturbed , with normally late - replicating dna shifting towards earlier periods within s - phase . barrier functions of repeat dna in the genome could be alleviated , allowing dna processing during repair and holiday junctions formed during recombination to pass through stretches of dna that are less accessible in normal cells . effects on cell stress and immune responses endogenous retroelements have been implicated in the regulation of cell stress responses , of the immune system , and in the pathogenesis of several human autoimmune diseases . the strongest data on regulation of human retroelements by cell stress concern alu sequences . likewise , the most convincing data on regulation of the immune system by retroelements and on the involvement in autoimmune diseases implicates hervs . there are , however , indications that l1 sequences too are induced during stress responses , during cytotoxic chemotherapy , and by uv exposure of skin cells . furthermore , l1 sequences may act in a similar fashion as hervs in at least one autoimmune disease , rheumatoid arthritis . in this disease , synovial fibroblasts become aberrantly activated in a fashion that resembles in many respects fibroblast activation in the stroma of malignant tumors , with enhanced proliferation , migration , and secretion of cytokines , chemokines , and proteases . the fibroblast genomes at large and l1 promoters in particular were found to become hypomethylated . overexpression of the p40 orf1 protein in this disease has been suggested to activate stress - induced protein kinases . it is thought that l1 hypomethylation and expression provide an amplification step in the pathogenesis of the disease by enhancing immune responses . the function of the activation of retroelements during cellular stress responses is poorly understood . conceivably , it forms part of a signaling system that alerts the immune system to the presence of infected or altered cells . if that proposition is true , hypomethylation and activation of l1 sequences in cancer cells are likely to influence the immune response to malignant tumors . in support of this idea , some herv proteins have been found to behave as tumor antigens [ 44 , 45 ] , but it is not known whether proteins encoded by l1 do so too . a similarly open question is to which extent hypomethylated repeat dna liberated from tumor cells elicits danger signals in cells regulating the immune response . interestingly , l1 activation is considered as a cause of increased plasma dna levels in tumor patients . many of the effects that can be envisioned to be exerted by activated l1 retrotransposons have indeed been observed in the human germline and during fetal development [ 13 , 47 , 48 ] . in cancer cells , mainly three phenomena point towards a reactivation of retroelements . retroelement dna sequences become hypomethylated , transcripts as well as protein products can be detected , and l1 sequences are located at sites of breakage and recombination . for l1 retrotransposons , . data on l1 expression are scarce , in contrast to several reports on the expression of herv gene products . l1 sequences have been found at or near deletion ends and translocation breakpoints , but the precise frequency and the mechanisms involved remain to be determined . intriguingly , actual retrotransposition events are exceptional . in a large number of human cancers , decreased methylation of l1 sequences has been documented ( table 1 ) . this decrease occurs in the context of general alterations in dna methylation patterns that accompany carcinogenesis in many human tissues . these are regarded as part of an important epigenetic mechanism driving cancer development and progression . alterations of methylation in cancer cells comprise hypermethylation which occurs focally and in a largely specific fashion , typically at cpg islands surrounding the transcriptional start regions of individual genes . somewhat paradoxically , in many , but not all cancers , increased methylation at specific sites is found alongside a decrease in methylation levels of the overall genome . the decrease in methylation appears to be relatively unspecific and is therefore commonly designated as genome - wide or global hypomethylation [ 64 , 65 ] . in normal somatic cells , the bulk of methylcytosine is found in repetitive sequences such as l1 , hervs , and alus , but also at cpg - rich satellites such as sat2 and sat3 . the overall decrease in methylation found in cancer cells therefore reflects a largely parallel decrease in the methylation of retrotransposon sequences . as a rule , however , hypomethylation of l1 sequences has traditionally been investigated by southern blot analysis following digestion of dna with methylation - sensitive restriction enzymes . recently , methods employing pcr following bisulfite treatment of dna have been developed for this purpose [ 52 , 66 ] . these techniques are promising , since they can also be applied to small amounts of suboptimal quality dna . however , because of the heterogeneity of l1 sequences , the extent of their demethylation is difficult to estimate precisely , especially by pcr - based methods . southern blot analyses suggest that in cancer cell lines up to 70%80% of cpg sites in l1 sequences become demethylated . accordingly , individual herv proviruses are essentially unmethylated in cancer cell lines with strong hypomethylation . nevertheless , l1 hypomethylation is anything but uniform in different cancers , in two respects . first , different extents of hypomethylation are found in cancers of the same type . these differences are also observed in cancer cell lines and are therefore not explained by differences in the proportion of tumor cells in tissue samples . second , l1 hypomethylation appears to develop at different stages in the development of different cancers . for instance , it is found at early stages of colon and bladder cancers [ 53 , 60 ] , but only in higher - stage prostate carcinomas [ 55 , 56 ] while primary renal carcinomas lack significant line-1 hypomethylation [ 52 , 53 ] . germ cell cancers are a special case since they have generally hypomethylated genomes , presumably due to their origin from cells with lower methylation levels [ 67 , 68 ] . accordingly , l1 [ 51 , 69 ] and herv sequences are strongly hypomethylated in testicular cancers . finally , note that very little is known on the methylation of individual l1 sequences , and accordingly , whether their hypomethylation in cancers is uniform . although genome - wide hypomethylation in human cancers has been known for more than twenty years , the mechanisms eliciting this alteration are still unknown . hypothetical mechanisms include insufficient levels of methyl group donors , ultimately of s - adenosylmethionine , inadequate expression or regulation of dna methyltransferases , reexpression of dna demethylases , and altered expression of chromatin regulators directing dna methyltransferases [ 64 , 65 ] . retroelements constitute approximately 45% of the human genome and contain an at least proportionate amount of methylcytosine . moreover , they appear to be preferentially recognized by the dna methylation machinery and at least in some circumstances appear to act as centers of methylation from which methylation spreads into adjacent sequences . therefore , genome - wide hypomethylation could theoretically arise as a consequence of a defect in the recognition of retroelements as methylation targets . unfortunately , it is still not known how retroelements are distinguished for silencing in mammalian genomes . therefore , l1 silencing in somatic cells can not be simply a consequence of transcriptional inactivity . instead , silencing must have been actively established during fetal development and is faithfully maintained through cell proliferation and differentiation in normal somatic cells . dna methylation of retroelements is established first during germ cell development and then again during gastrulation , when the genome at large becomes de novo methylated , except for sequences that are actively protected , such as cpg islands and active imprinted genes . de novo methylation in the mouse embryo requires dna methyltransferases , specifically dnmt3a and dnmt3b as well as dnmt1 for maintenance of the established methylation [ 74 , 75 ] . in male germ cells it is not entirely clear whether methylation of l1 during development requires specific chromatin regulators directing the methyltransferases . one candidate is smarca6 , as its mouse orthologue lsh has been found to be required for proper methylation of l1 sequences . inactivation of lsh in mice causes l1 hypomethylation , but only limited disturbances of the methylation of single - copy genes . in comparison , inactivation of another chromatin protein atrx causes hypomethylation of rdna , but leaves l1 methylation intact . this suggests that the specificity of dna methylation may be regulated by specific chromatin regulator proteins . a variety of chromatin regulator proteins have been reported to be aberrantly expressed or even mutated in human cancers [ 65 , 79 81 ] . however , many of these changes are rare or are specific to particular cancers . it is therefore difficult to envision a change in a single master regulator of l1 methylation as the cause of the widely distributed hypomethylation of these sequences . more likely , l1 hypomethylation could be associated with the general reorganization of chromatin structure in aneuploid cancer cells that disturbs the compartmentation of the genome [ 65 , 79 , 80 ] . genome - wide alterations in histone modification have recently been described in cancer cells [ 82 , 83 ] . given the high proportion of l1 sequences in the human genome , these are likely to affect these retrotransposons and to interact with their methylation . note that the relation between dna methylation and histone modifications at l1 sequences is far from being understood . l1 expression in cancers the mechanisms underlying hypomethylation changes in human cancers are not understood , but even the description of these changes is fragmentary . for instance , methylation of hervs has been studied in only a few cancers . available data suggest that they are affected by genome - wide hypomethylation in parallel to line-1 sequences ( table 1 ) . in selected cancers , endogenous retroviral sequences are found in germ cell cancers and antibodies directed against herv - encoded proteins are found in the blood of patients . in cancers of somatic cell origin , bona fide transcripts for envelope and auxiliary proteins have been reported , especially in breast cancer [ 44 , 85 ] , and recently in melanoma . some results suggest that herv expression occurs in a wider range of cancers and even normal tissues [ 87 , 88 ] . these data need further verification to exclude artifacts from genomic dna and unspliced transcripts . moreover , the somewhat surprising findings that different transcripts from different subfamilies may be expressed in a cancer - type - specific fashion call for a closer analysis of the mechanisms involved . the available data suggest that expression of full - length l1 sequences is by far the strongest in teratocarcinomas , while weaker expression is observed in a wider range of carcinomas exhibiting hypomethylation . this expression pattern therefore resembles that of hervs . since hervs also give rise to spliced transcripts , rna analyses can provide a first indication of which protein products are expressed . for l1 so far , no definite data have been published on the expression of the proteins encoded by the retrotransposons in human cancer . their presence in germ cell cancers and teratocarcinoma cell lines , however , is very likely . involvement of l1 in chromosome breakage and recombination whereas retrotransposition events take place quite regularly in the germline , at an estimated rate of 1 event per 100 births [ 3 , 4 ] , very few have been reported in cancer cells [ 90 , 91 ] . similarly , although l1 sequences have been shown to become incorporated at sites of double - strand break dna repair in model experiments , according sequence changes have only exceptionally been observed in human cancers . in spite of the caveats discussed below , it is therefore probably safe to conclude that actual retrotransposition events are rare in human cancers and do not regularly contribute to genomic instability . the evidence is better for indirect mechanisms by which retrotransposons could promote chromosomal instability in human cancer . l1 hypomethylation and chromosomal instability correlate well with each other in several cancer types [ 55 , 58,94 ] . a similar relationship has been observed between the hypomethylation of tandem satellite sequences and alterations of the chromosomes that carry them as large juxtacentromeric region [ 9597 ] . in this case , hypomethylation of the satellite sequences is thought to cause decondensation of pericentromeric chromatin and an increased propensity for chromosomal breaks and rearrangements in this region . in a similar fashion , hypomethylation of retroelement sequences dispersed in the genome , l1 sequences are enriched at the ends of 3p14.1 and 9p21 deletions in carcinomas [ 36 , 98 , 99 ] and homozygous deletions arise preferentially in chromosomal regions with high line content . it has also been suggested that l1 and herv sequences are involved in the formation of double - minute circular chromosomes in cancer cells [ 101 , 102 ] . the most straightforward hypothesis accounting for these findings is that decreased methylation and presumably more open chromatin structure at l1 sequences in cancer cells favors the illegitimate recombination between elements at different genomic locations , for example , during homologous recombination repair of dna strand breaks . however , closer analyses of the deletion ends in solid tumors indicate that this hypothesis is probably incorrect . while deletion ends are indeed often located in or near l1 sequences and particularly l1 clusters , the breakpoints invariably show hallmarks of dna double - strand break repair by nonhomologous end - joining ( nhej ) . typically , one end of the deletion is located in or close to an l1 sequence , while the other end is provided by an unrelated single copy or repeat sequence [ 36 , 99 , 103 ] . such structures also appeared as occasional end products of repair of dna double - strand breaks induced by a restriction endonuclease at a specific chromosomal site . a plausible explanation for this structure is that processing by the nhe1 protein complex damaged dna ends is slowed down at l1 sequences by denser chromatin , favoring reannealing and ligation there . if this explanation is correct , retroelement hypomethylation in cancer could paradoxically diminish the tendency of breakpoints to be located at l1 sequences . it would instead tend to increase the size of deleted and recombinated sequences , because dna processing and holiday junctions arising during recombination repair could move further through more open chromatin . first of all , far too few chromosomal breakpoints have been investigated , especially in carcinomas . secondly , it has not been established for any chromosomal alteration whether hypomethylation of repeat sequences at the affected site preceded it . they might be associated with local structures that are particularly prone to breakage , such as fragile sites or the anchorage sites of chromatin loops . retrotranspositions in the germline take place at a significant rate of approximately 1 event per 100 births . in addition , a substantial number of recombination events involving l1 elements have been detected , typically because they elicited translocations or rearrangements causing inherited diseases [ 2 , 47 , 48 ] . specifically , l1 retrotransposition and illegitimate recombination in the germline are causes of inherited and congenital cancers . for instance , a germline deletion in the mlh1 gene carries hallmarks of recombination initiated by a failed l1 retrotransposition event . in contrast , in spite of considerable evidence hinting at a reactivation of l1 retrotransposons in a variety of human cancers , there is limiting evidence for major consequences of this process . one is technical : even typical effects expected from l1 reactivation are difficult to detect by the techniques commonly used to investigate genetic alterations in human cancers . the other is biological : reactivation may be partial and the mechanisms ensuring silencing of l1 dna sequences and limiting the effects of transcribed sequences may remain functional to some degree . perhaps , limited reactivation of l1 sequences may exert effects more through the loss of symbiotic functions than through direct adverse effects on genomic stability . this possibility is even more difficult to ascertain . in general , investigations of genetic and epigenetic changes in human cancers avoid dealing with repeat sequences and focus on single - copy protein - coding genes . mutation analysis of genes is typically restricted to coding sequences and employs pcr techniques to analyze individual exons or mrna . insertions or recombinations caused by l1 or other retroelements would often not be detected by this approach , unless they occur within exons . therefore , it might not be coincidental that reports describing oncogene activation and tumor suppressor inactivation by l1 insertion date from a period when southern blot analysis was more en vogue . similarly , recombination and deletions in cancers are well documented at the level accessible by cytogenetic techniques , but are not well investigated at the molecular level , with the important exception of translocations in hematological cancers . in these , retroelements have indeed been found at many translocation sites , although their role in the generation of the translocations is not clear . in contrast , very few studies have addressed the precise structure of chromosomal breakpoints in solid tumors . a recent genome - wide study of 505 cancer cell lines yielded a strong association between line content and the presence of homozygous deletions , but no breakpoints were characterized in detail . detailed analyses of deletion endpoints at the fra3b fragile site and around cdkn2a at 9p21 revealed a preponderance of l1 sequences at or close to the deletion endpoints . such analyses remain tedious even with the finished human genome sequence having become available . therefore , we know little on the structure of amplicons , another category of unstable sequence in cancer cells , and next to nothing on the sites of illegitimate recombination in cancer cells . l1 sequences have been detected in double minutes , an important intermediate in one amplification mechanism , and have been proposed , but not proven to be involved in their formation . by a comparison of loss of heterozygosity analysis and cytogenetic techniques of chromosome 8p in bladder cancer cell lines , recombination events were recently shown to be much more frequent and were shown to take place across much smaller regions than hitherto assumed . however , it is not known and difficult to determine what initiated the recombination events and which sequences precisely were involved . in summary , therefore , whereas it seems unlikely that retrotransposition is common in human cancer cells , the role of l1s in recombination and chromosome breakage is probably underestimated due to a lack of studies with appropriate methodology . a similar argument can be made for epigenetic effects of l1 sequences in cancer . in genome - wide screens for altered methylation in cancer , repeat sequences are often and understandably considered a nuisance and typically removed by prehybridization . overall changes in l1 methylation are therefore well documented , but data on the behavior of individual sequences is lacking . bisulfite sequencing is restricted to a few hundred bp per pcr and is prone to artifacts from template switching and target priming when applied to repeat sequences . this method has revealed that in fetal fibroblasts , the promoters of most full - length l1 sequences are densely and symmetrically methylated , while selected elements are unmethylated . accordingly , it is not clear whether the number of completely unmethylated elements increases in cancer cells or whether the decrease in methylation is distributed across all l1 sequences . these questions extend of course to the issue of chromatin structure at l1 elements . the contribution of l1s to altered gene expression in cancer perhaps most striking are reports on frequent downregulation of genes ( usually tumor suppressor candidates ) without detectable genetic alterations in their vicinity and altered dna methylation in regulatory sequences . recently , increased expression of mirna has been introduced as a potential cause of such enigmatic observations . in the light of potential effects of l1 sequences , perhaps effects exerted by l1 elements in or near affected genes this suggestion likewise applies the mechanisms generating aberrant transcripts in cancer cells . again , this is a highly difficult issue , especially if genes that are investigated are alternatively spliced even in normal cells . the argument can be broadened further to encompass the potential boundary function of repeat elements . its disturbance by altered chromatin structure in cancer cells may result in more or less subtle up- and downregulation . more than two decades of intense work have been spent on a small number of selected loci to understand the mechanisms of action of long - range regulatory elements and boundary elements at all . it is understandable that very little is known on how they are altered in cancer cells . still , it may be advisable to consider such effects and others mentioned in this paragraph when encountering instances of altered gene regulation in cancer that can not be straightforwardly explained by mutations or altered dna methylation of gene regulatory sequences . the difficulties in determining the impact of l1 sequences in cancer cells resulting from methodological limitations are compounded by biological factors . it is likely that this restriction of transcriptional activity is aided by an inactive chromatin structure , although this can not be considered proven . a second set of l1 controls appears to act at the rna level , perhaps exerted by cytidine deaminases , leading to rna instability . alu - containing rnas are subject to editing [ 1618 ] , but the evidence for l1 rna is scanty . active tp53 prevents retrotransposition , but this is very likely not the only barrier at this step . last and perhaps not least , there is some evidence that retroelement activation might attract immune responses . as discussed elsewhere in detail , such responses are better documented for hervs , but they might additionally or concurrently select against cells with strongly activated l1 retrotransposons outside immunoprivileged organs . there is good evidence for three of these protective mechanisms to be impeded in cancer cells : dna methylation is decreased , tp53 and checkpoints are often defective , and immune responses to advanced cancers are muted . we know very little about another mechanism , control of retroelements at the rna level . in summary , therefore , the regulation of l1 genomic structure , expression , and retrotransposition is clearly perturbed in many human cancers , but inactivation of all tiers of control may be rare . some cancer types exhibit few changes , for example , renal cell carcinoma , where even l1 dna methylation appears to be maintained , while germ cell cancers appear to represent the other end of the spectrum [ 49 , 50 , 52 , 53 ] . even in these , however , retrotransposition events appear to be rare and the evidence for major contributions of retrotransposon activity to the cancer phenotype is limited . a likely candidate is tp53 , since germ cell tumors are among the few cancer types in which mutations of this tumor suppressor are rare . activation of l1 retrotransposons in cancer cells is expected to exert a variety of effects on the tumor phenotype , if it occurs . of course , this statement hinges on the if , and our present knowledge does not allow firm conclusions . considering that l1 retrotransposons make up almost a fifth of our genome , there are astonishingly large gaps in our knowledge on their general biology , and consequentially in our knowledge on their behavior in cancer . as argued above , there is an obvious need for more systematic investigations of dna methylation and chromatin structure of l1 dna , of the expression of full - length transcripts and l1-encoded proteins on one hand and for exemplary studies of individual elements and their influence on adjacent genes in cancer cells on the other hand . at this stage , it is probably safe to conclude that l1 retrotransposons do become reactivated to various degrees in different cancers , but that some of the many safeguards that prevent retrotransposition and their adverse effects in somatic cells hold up in most cancers . it follows that more subtle effects of l1 dysregulation in cancer cells , which may include adverse actions as well as loss of symbiotic functions , should be a focus of investigation . potential effects of l1 sequences on transcriptional regulation . ( a ) schematic view of a human gene . one l1 element is located upstream of the gene and one within . panels ( b)(g ) show various disturbances that could be caused by partial or complete reactivation of l1 elements : ( b ) deregulation by upstream l1 promoter ; ( c ) transcriptional interference by the promoter of an l1 in inverse direction to the gene ; ( d ) generation of an alternative 5-truncated transcript by an internal l1 promoter in sense direction ; ( e ) generation of an alternative 5-truncated transcript by the antisense promoter of an internal l1 element in inverse direction to the gene ; ( f ) transcriptional interference by the antisense promoter of an internal l1 element oriented in sense direction ; ( g ) generation of a truncated transcript by use of the poly - adenylation site of an internal l1 element . note that most effects do not require intact retrotransposons . postulated boundary effect of intergenic l1 clusters . being strongly methylated and tightly packed into chromatin , clustered l1 sequences might act as boundaries between genes , restricting the interaction of an enhancer ( enh ) to one gene ( a ) . in cancer cells , l1 hypomethylation could destroy this function and cause deregulation by allowing enhancer interaction with a neighboring gene ( b ) . Output:	retrotransposons like l1 are silenced in somatic cells by a variety of mechanisms acting at different levels . protective mechanisms include dna methylation and packaging into inactive chromatin to suppress transcription and prevent recombination , potentially supported by cytidine deaminase editing of rna . furthermore , dna strand breaks arising during attempted retrotranspositions ought to activate cellular checkpoints , and l1 activation outside immunoprivileged sites may elicit immune responses . a number of observations indicate that l1 sequences nevertheless become reactivated in human cancer . prominently , methylation of l1 sequences is diminished in many cancer types and full - length l1 rnas become detectable , although strong expression is restricted to germ cell cancers . l1 elements have been found to be enriched at sites of illegitimate recombination in many cancers . in theory , lack of l1 repression in cancer might cause transcriptional deregulation , insertional mutations , dna breaks , and an increased frequency of recombinations , contributing to genome disorganization , expression changes , and chromosomal instability . there is however little evidence that such effects occur at a gross scale in human cancers . rather , as a rule , l1 repression is only partly alleviated . unfortunately , many techniques commonly used to investigate genetic and epigenetic alterations in cancer cells are not well suited to detect subtle effects elicited by partial reactivation of retroelements like l1 which are present as abundant , but heterogeneous copies . therefore , effects of l1 sequences exerted on the local chromatin structure , on the transcriptional regulation of individual genes , and on chromosome fragility need to be more closely investigated in normal and cancer cells .
PubmedSumm118822	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: vietnam war veterans experience significantly increased mortality and morbidity as a result of chronic diseases as compared to the australian population ( 2,7 ) . regular exercise is known to improve health , fitness ( 12 ) and psychological health ( 15 ) in vietnam veterans , therefore this cohort should undertake regular exercise to reduce the likelihood and occurrence of mortality / morbidity attributed to chronic diseases and psychological conditions ( 16 ) . perceived barriers to exercise compliance include poor health , lack of physician support , lack of time , inadequate instruction and lack of social support ( 1,19 ) , with long - term exercise adherence reported at 4650% for the older population ( 18 ) and specifically war veterans ( 12,14 ) . further , a person s subjective experience of their first exercise session may indicate their likelihood of long - term exercise compliance ( 8) , and therefore should be considered by those designing exercise interventions particularly for elderly participants . due to their largely sedentary lifestyles , vietnam veterans may also be at risk of noncompliance due to fatigue associated with commencing an exercise program , therefore innovative exercise interventions that are reported as more time efficient and less fatiguing than the traditional exercise modalities may provide a viable alternative . one such exercise modality is vibration training . while more time efficient and less fatiguing than other modalities ( 4 ) vibration training results in similar functional improvements in the elderly compared to exercise without vibration ( 17 ) . further , vibration training improves strength ( 9 ) , cardiovascular fitness ( 5 ) , mobility ( 11 ) and glycemic control ( 3 ) , is effective for relieving pain ( 10 ) and results in sustained exercise participation ( 4 ) in the elderly . the aim of the current pilot study was to determine the effect of an acute bout of exercise on the subjective exercise experience of vietnam veterans , and to determine which exercise intervention results in the most positive acute outcome . specifically , this study included the use of a combination of traditional exercise modes ( stretching , aerobic exercise and resistance training ) and innovative exercise ( vibration trainers ) . it was hypothesised that following an acute exercise bout , programs incorporating vibration training would result in the least fatigue and that all acute exercise bouts would elicit improved positive well being and decreased psychological distress . this research has practical significance to those training the elderly , previously sedentary population . specifically , the long - term implementation of the intervention eliciting the most positive acute subjective experience should increase exercise adherence , resulting in improved health , fitness and quality of life of the elderly population vietnam veterans ( n = 32 , age = 62 4 yr , bmi = 33 5 kgm ) volunteered , obtained medical clearance from their medical practitioner and gave written informed consent to participate in the study . the participants presented with a high prevalence of chronic diseases / conditions with the most prevalent being psychological conditions such as posttraumatic stress disorder and depression ( 63% ) , followed by high blood pressure ( 56% ) , high cholesterol and knee pain ( 45% ) , back pain ( 40% ) , cardiovascular disease ( 25% ) , and diabetes and neurological conditions ( 13% ) . prior to participation in this study , all participants had been previously sedentary for at least 24 months . all procedures were approved by the university human ethics subcommittee prior to the commencement of the project , with procedures carried out in accordance with the declaration of helsinki . prior to participating in the acute exercise bout , participants were measured for height and mass to determine their bmi ; and had their resting heart rate and blood pressure assessed as a precautionary measure , with all participants cleared to participate in the exercise session . participants were allocated to one of three exercise groups , 1 ) lower - body vibration exercises plus upper - body resistance ( wbvt ) 2030 min ; 2 ) lower - body vibration plus upper - body resistance plus aerobic exercise ( wbvt+cv ) 4060 min or 3 ) full - body resistance plus aerobic exercise ( r+cv ) 4060 min ( table 1 ) . any participant who presented with a potential contraindication to vibration training exercise such as metal pins / plates ( n=5 ) or pacemakers ( n=1 ) were assigned to group 3 , with the rest of the participants randomly allocated to one of the three groups . there were no significant differences in age , bmi , resting heart rate or resting blood pressure between groups . aerobic exercise consisted of a combination of treadmill walking , ergometer cycling and/or ergometer rowing at a moderate intensity ( unable to maintain a conversation due to associated breathlessness ) for 10 minutes at the start and 10 minutes at the end of the session . lower - body vibration exercises ( table 1 ) were performed on a vibrating platform with handles ( hypervibetm , noosaville , australia ) at a vibration frequency of 15hz for 30s , for two sets . the upper - body resistance exercises ( table 1 ) consisted of two sets of 10 repetitions . the resistance exercises were performed on hydraulic exercise machines ( fitness technology , skye , australia ) with the level of resistance set individually for each participant to achieve muscle fatigue ( but not failure ) by the end of each set . this single bout , acute investigation represents a portion of a larger 12-week training intervention study . immediately before and 5 min after the single exercise bout , participants were asked to sit down and complete the subjective exercise experience scale , a valid and reliable instrument ( sees ) ( 13 ) used previously to describe acute exercise affect ( 6,8 ) . the sees is a 12-item instrument with four items each representing positive well being ( great , positive , strong , terrific ) , psychological distress ( awful , crummy , discouraged , miserable ) and fatigue ( drained , exhausted , fatigued , tired ) with each item rated along a likert scale from 1 ( not at all ) to 7 ( very much so ) . scores for positive well being , psychological distress and fatigue are reported as the sum of the scores for the four items that represent each category , with a maximum attainable score of 28 for each category . data was analysed using the statistical package for the social sciences ( spss inc , v16.0 ) and reported as means sd . a 32 , conditions ( wbvt , wbvt+cv , r+cv ) time ( pre - exercise , postexercise ) , repeated measures anova with post hoc tukey hsd was used to identify significant differences in the four sees items . vietnam veterans ( n = 32 , age = 62 4 yr , bmi = 33 5 kgm ) volunteered , obtained medical clearance from their medical practitioner and gave written informed consent to participate in the study . the participants presented with a high prevalence of chronic diseases / conditions with the most prevalent being psychological conditions such as posttraumatic stress disorder and depression ( 63% ) , followed by high blood pressure ( 56% ) , high cholesterol and knee pain ( 45% ) , back pain ( 40% ) , cardiovascular disease ( 25% ) , and diabetes and neurological conditions ( 13% ) . prior to participation in this study , all participants had been previously sedentary for at least 24 months . all procedures were approved by the university human ethics subcommittee prior to the commencement of the project , with procedures carried out in accordance with the declaration of helsinki . prior to participating in the acute exercise bout , participants were measured for height and mass to determine their bmi ; and had their resting heart rate and blood pressure assessed as a precautionary measure , with all participants cleared to participate in the exercise session . participants were allocated to one of three exercise groups , 1 ) lower - body vibration exercises plus upper - body resistance ( wbvt ) 2030 min ; 2 ) lower - body vibration plus upper - body resistance plus aerobic exercise ( wbvt+cv ) 4060 min or 3 ) full - body resistance plus aerobic exercise ( r+cv ) 4060 min ( table 1 ) . any participant who presented with a potential contraindication to vibration training exercise such as metal pins / plates ( n=5 ) or pacemakers ( n=1 ) were assigned to group 3 , with the rest of the participants randomly allocated to one of the three groups . there were no significant differences in age , bmi , resting heart rate or resting blood pressure between groups . aerobic exercise consisted of a combination of treadmill walking , ergometer cycling and/or ergometer rowing at a moderate intensity ( unable to maintain a conversation due to associated breathlessness ) for 10 minutes at the start and 10 minutes at the end of the session . lower - body vibration exercises ( table 1 ) were performed on a vibrating platform with handles ( hypervibetm , noosaville , australia ) at a vibration frequency of 15hz for 30s , for two sets . the upper - body resistance exercises ( table 1 ) consisted of two sets of 10 repetitions . the resistance exercises were performed on hydraulic exercise machines ( fitness technology , skye , australia ) with the level of resistance set individually for each participant to achieve muscle fatigue ( but not failure ) by the end of each set . this single bout , acute investigation represents a portion of a larger 12-week training intervention study . immediately before and 5 min after the single exercise bout , participants were asked to sit down and complete the subjective exercise experience scale , a valid and reliable instrument ( sees ) ( 13 ) used previously to describe acute exercise affect ( 6,8 ) . the sees is a 12-item instrument with four items each representing positive well being ( great , positive , strong , terrific ) , psychological distress ( awful , crummy , discouraged , miserable ) and fatigue ( drained , exhausted , fatigued , tired ) with each item rated along a likert scale from 1 ( not at all ) to 7 ( very much so ) . scores for positive well being , psychological distress and fatigue are reported as the sum of the scores for the four items that represent each category , with a maximum attainable score of 28 for each category . data was analysed using the statistical package for the social sciences ( spss inc , v16.0 ) and reported as means sd . a 32 , conditions ( wbvt , wbvt+cv , r+cv ) time ( pre - exercise , postexercise ) , repeated measures anova with post hoc tukey hsd was used to identify significant differences in the four sees items . the mean sd scores for positive well being , psychological distress and fatigue before and after the exercise bout for each of the exercise interventions are shown in table 2 . the purpose of the current study was to compare the effect of an acute bout of different exercise interventions on the subjective experience of vietnam veterans . all exercise bouts improved positive well being . while not significant , the wbvt and the r+cv bouts decreased fatigue and psychological distress while the wbvt+cv increased these factors . twenty - three participants ( 72% ) reported improved positive well being following an acute bout of exercise , resulting in a significant increase in positive well being for the combined participants . further , all individual exercise interventions showed non - significant improvements in positive well being , with the r+cv group demonstrating the biggest change . the improved positive well being after exercise is in agreement with research on both young and middle - aged female adults ( 6 , 8) with participants reporting improved positive well being after low , moderate and high intensity walking . however neither study showed a significant effect of exercise intensity on fatigue or psychological distress . in the current study , fifteen participants ( 47% ) reported less psychological distress following exercise while five participants reported increased psychological distress . as a combined group , a significant decrease in psychological distress after exercise was reported . while not significant , the wbvt and r+cv groups demonstrated a decline in psychological distress , while the wbvt+cv group reported sightly increased psychological distress following exercise . fifteen participants ( 47% ) increased fatigue , six participants reported no change and 11 participants decreased fatigue following exercise . despite no significant differences between groups , wbvt and r+cv groups reported slight decreases in fatigue while wbvt+cv increased fatigue . specifically , while wbvt+cv reported the lowest pre - exercise fatigue levels , this group reported the highest post - exercise fatigue . the current study indicates that an acute bout of exercise , regardless of the intervention , resulted in increased positive well being for previously sedentary vietnam veterans , with the wbvt and r+cv groups both reporting improvements across all areas of the sees . while increasing positive well being , wbvt+cv resulted in slightly increased psychological distress and the greatest increase in fatigue , therefore this intervention may be the least effective in eliciting an overall positive subjective experience of acute exercise in vietnam veterans a reason for these results may be that the participants found wbvt+cv too complicated , with the program containing a combination of four types of activities ( stretching , vibration , resistance and aerobic exercise ) while the other interventions utilised only three activities . commencing an exercise regime with a program that elicits immediate positive responses may increase exercise adherence ( 8) . given the risk of noncompliance in the current cohort with previous reports of 48% long - term exercise adherence for vietnam veterans ( 12 ) , exercise professionals may best serve their clients by commencing with a simple exercise program to provide the greatest likelihood of positive experience after the first session . it has already been established that vibration training improves a variety of health ( 3 ) , fitness ( 5 , 9 , 11 , 17 ) and quality of life ( 10 ) measures in the largely sedentary , elderly population . these known benefits , along with the current finding that acute vibration training elicits positive subjective experiences in the elderly , indicate that vibration training may provide a useful alternative to traditional exercise , however further investigation is warranted to determine whether vibration training alone elicits positive responses to exercise . the positive experience associated with acute exercise is an important finding for the vietnam veteran population . the increased incidence of chronic disease ( 2 ) , the low exercise adherence ( 12 ) and the health , fitness and quality of life benefits of regular exercise ( 12 , 15 ) in vietnam veterans is well documented . prescribing exercise that elicits an acute positive experience is likely to result in increased exercise adherence , which may decrease the incidence and severity of chronic disease and increase overall quality of life in vietnam veterans . overall this pilot study has demonstrated that an acute bout of exercise for previously sedentary elderly war veterans presenting with a combination of chronic conditions elicits improved positive well being and reduced psychological distress , and therefore warrants further research with a larger cohort to determine which exercise intervention results in the most beneficial subjective experience . the identification of specific exercise interventions that elicit acute positive exercise experiences has important implications for long - term exercise adherence in at - risk populations . Output:	a person s subjective experience to their first exercise session is likely to influence their long - term adherence to regular exercise . the aim of the current pilot study therefore is to quantify the subjective exercise experience of previously sedentary vietnam war veterans undertaking an initial bout of one of three different exercise interventions . thirty - two vietnam veterans presenting with one or more chronic diseases / conditions participated in one of three acute exercise bouts : 1 ) lower - body vibration , upper - body resistance and stretching ( wbvt ) ; 2 ) lower - body vibration , upper - body resistance , aerobic exercise and stretching ( wbvt+cv ) ; and 3 ) full - body resistance , aerobic exercise and stretching ( r+cv ) . pre and post acute exercise measures of positive well being , psychological distress and fatigue were assessed with the subjective exercise experiences scale ( sees ) . a 3(conditions ) 2(time ) repeated measures anova with post - hoc tukey hsd was used to identify any significant differences in sees between exercise groups and pre and post - exercise . all interventions increased positive well being , with wbvt and r+cv reporting improvements across all areas of the sees . the wbvt+cv group reported slightly increased psychological distress and the greatest increase in fatigue . an acute bout of exercise increases positive well - being in previously sedentary war veterans however a longer - duration exercise bout containing multiple exercise modes may be too demanding for this population . exercise professionals should consider commencing with a simple program to minimise psychological distress and fatigue as this may negatively impact on exercise adherence .
PubmedSumm118823	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: spinal surgery in obese patients often poses challenges not only to proper patient positioning , but also to obtaining adequate surgical exposure and frequently leads to increased complexity of the procedure and risk for the patient . the excessive subcutaneous fat deposition in obese patients group can be daunting with regard to the surgical approach to the bony structures of the spine3 ) . the general rule has been to increase the length of the incision to allow adequate visualization at depth7 ) . the additional tissue injury associated with an increase in incision length and depth is likely a factor in the operative site morbidity6 ) . therefore , the operation has been associated with increased operation time , blood loss , wound infection , and other many perioperative complications10 ) . but , whether or not the body mass index ( bmi ) affects the surgical outcomes in obese patients is unclear and forms the basis of this study . we retrospectively analyzed a consecutive series of lumbar microdiscectomies performed in a single center with a minimum 6-month follow - up . our focus was the effect of patients ' bmi on one - level lumbar microdiscectomy . the hypothesis of the study was that obese patients would have worse outcomes than nonobese patients . we analyzed all patients who underwent one - level lumbar microdiscectomy performed at our institution between june 2003 and march 2007 . indications for surgery were intractable pain that had not responded to conservative management for 6 - 8 weeks and intervertebral disc herniation with compression of nerve root confirmed by magnetic resonance imaging . the hospital charts from these patients were reviewed and each patient 's bmi was calculated . patients with a history of previous lumbar spinal surgery , with foraminal disc herniation treated with lateral approach were excluded . patients treated with discectomy using tubular retractors were also excluded because there was the possibility of false interpretation . the bmi was based on the patient 's height and weight recorded in the patient 's chart at the time of the surgery . patients were classified into three groups , based on their bmi : normal weight , overweight and obesity . as defined by the national institutes of health , some with a bmi less than 25.0kg / m were considered as normal , others with 25.0 kg / m to 29.9 kg / m were overweight , and others with a bmi of 30.0 kg / m or greater were categorized as obese2 ) . patient demographics included bmi , gender , age , comorbidities , smoking habit , current medications , side of surgery , level of surgery , and time of maximum follow - up . intake of medications including aspirin , clopidogrel , and cilostazol was checked by chart review . operation time , estimated blood loss ( ebl ) , postoperative hospital day , recurrence , intraoperative durotomy , and postoperative epidural steroid injection were compared as surgical outcomes for obese , overweight , and normal patients . the surgery was reserved for patients with new neurological deficits occurring after recurrent disc herniation or persistent radicular symptoms despite nonsurgical management such as oral analgesia , physical therapy , and epidural steroid injections . to adjust for statistically significant demographic differences and surgical outcomes among groups , analysis of variance was used to evaluate differences in non - continuous variables , whereas the regression analysis was used to assess differences in continuous variables . to evaluate factors potentially impacting the operation time and ebl , covariates analyzed were gender , age , comorbidities , current medications , smoking habit , level or side of surgery , and duration of follow - up . in this study , 129 patients were enrolled in this study among patients who underwent one - level lumbar microdiscectomy . demographic and descriptive characteristics of the study cohort are presented in table 1 . of these , over half of the patients ( 57.4% ) were normal ( n=74 ) , 34.9% were overweight ( n=45 ) , and 7.8% were obese ( n=10 ) . mean age was 49.4 years ( range : 20 - 78 years ) for normal patients , 52.9 years ( range : 19 - 76 years ) for overweight patients , and 41.7 years ( range : 16 - 78 years ) for obese patients . the incidence of hypertension , diabetes mellitus , and hyperlipidemia was respectively 23.0 , 13.5% , and 6.8% in normal patients . correspondingly , the incidence was 31.1 , 8.9 , 6.7% in overweight patients . intake of aspirin was noted in 10.8% of normal patients , 11.1% of overweight patients , and 30.0% of obese patients . in all groups , discectomy was mainly made on the left side . the most common spine level operated on we performed multivariate analyses based on patients ' gender , age , comorbidities , current medications , smoking habit , level or side of the surgery , and follow - up duration . the average operation time was significantly longer in the obesity ( 99.3 min in the normal group , 110.2 min the overweight group , and 119.0 min in the obese group ; fig . the average ebl was also increased in the obesity ( 85.2 cc in the normal group , 116.1 cc in the overweight group , and 177.5 cc in the obese group ; fig . this confirmed the statistically significant association between obesity and surgical outcomes , including operation time and ebl . as bmi is greater , as the operation time is longer ( p=0.004 , beta=2.354 ) and the ebl is more ( p=0.014 , beta=8.889 ) . in particular , linear regression models were used to predict the relationships between bmi and surgical outcomes including operation time ( fig . this implies that 2.35 minute in the operation time is longer and 8.89 cc in ebl is much more , as bmi of 1 kg / m is increased . no substantial clinically relevant differences were observed for mean postoperative hospital day ( 6.9 days in normal group , 7.4 days in overweight group , and 6.5 days in obese group ) . of our patients who had microdiscectomy , 22 had reoperation for recurrent disc herniation ( 17.1% ) . there were no significant differences in other surgical outcomes , including postoperative hospital day ( p=0.349 ) , recurrent disc herniation ( p=0.901 ) , intraoperative durotomy ( p=0.414 ) , and postoperative epidural steroid injection ( p=0.590 ) among the groups . to determine the risk factors of operation time and ebl , among clinical characteristics , a regression analysis was done . multivariate regression analysis demonstrated that women ( p=0.026 , beta=14.389 ) and hypertension ( p=0.002 , beta=18.788 ) were significant factors for operation time . analysis for ebl showed that high level surgery ( p=0.049 , beta=-31.620 ) had more bleeding risk compared with low level surgery . spine surgery in the obese is a challenging endeavor for many reasons , including anesthetic considerations , intravenous access , and positioning , as well as the procedure itself9 ) . retraction was difficult and visualization of the important elements of the operation was obscured by the patient 's depth4 ) . this study was performed to evaluate outcomes after lumbar microdiscectomy in patient who are obese . although obesity has been shown to result in longer operation time and more intraoperative bleeding , it was not clear from previous reports if the surgical outcomes were dependent on the degree of obesity . a previous study comparing perioperative findings between obese and nonobese patients undergoing lumbar spine surgery demonstrated no difference in operation time , ebl , or length of hospital day1 ) . but , other study by jeffrey et al . demonstrated that obesity leads to increased operation time , ebl , and length of hospital day8 ) . we found a statistically significant difference in the operation time and ebl of obese patients compared with normal those . the coefficient for patients with a bmi above 25 kg / m was highly significant in the operation time and ebl . our study found that overweight or obese patients had a longer operation time and more intraoperative bleeding . but , there were no differences in surgical outcomes including postoperative hospital day , recurrent disc herniation , intraoperative durotomy , and postoperative epidural steroid injection . our results demonstrated that higher bmi might be not related with heightened morbidity in lumbar microdiscectomy . other factors associated with longer operation time and more intraoperative blood loss were found in multivariate regression analysis . gender , hypertension , and level of surgery also made an influence on the operation time and ebl . in this study , woman and hypertension were found to be a significant predictor of operation time and level of surgery was a predictor of ebl . conversely , another researcher reported that male and level of surgery were factors associated more intraoperative blood loss12 ) . the explanation for this difference in findings may be that the present study included patients with lumbar discectomy whereas the previous study evaluated patients with lumbar fusion surgery12 ) . this discrepancy warrants further investigation because risk factors to affect surgical outcomes are variable as the type of surgery . , the patients did n't show a higher recurrence rate even though with a higher bmi . previous investigator retrospectively reviewed 75 patients who had undergone a microdiscectomy , 8 ( 10.7% ) of whom had experienced a recurrent herniation5 ) . they associated obesity with a twelve times higher likelihood of postoperative recurrent herniation and a thirty times higher likelihood of requiring a reoperation and concluded that weight loss counseling should be incorporated in preoperative discussions . however , there was no confidence in reliability of the study , because of their small sample size . in our study which the sample size was larger than the previous study , there were no differences in surgical outcomes . additionally , our data demonstrated that age , current medications , smoking habit , side of the surgery , and follow - up duration are not significant predictors for the operation time or ebl . the use of a retrospective design from the cases at a single institution is a notable limitation of our study . as a retrospective case series , it has potential biases . the follow - up period ranged from 6 to 125 months with all patients having at least 6 months of follow - up . another weakness was that this follow - up duration is not extensive enough . in the future study , a longer follow - up period would prove useful and will endeavor to publish long - term results in the patients . in the current study , we could not investigate confounding baseline variables including level of education , income , marital status , and occupation , differed among three groups . these differences may have affected the results of the present study . in total of 129 patients , the proportion of obesity was too small in the study , which could be a limitation . finally , the imprecision of bmi as a marker of obesity was another important limitation . other measures , such as skin - fold thickness or body surface area , may be more specific measures of obesity to include in future studies . in summary , this analysis does n't support the hypothesis that patients with higher bmi are likely to encounter heightened morbidity in lumbar microdiscectomy . although the operation time and ebl was significantly increased in obesity , there were no differences in surgical outcomes including postoperative hospital day , recurrent disc herniation , intraoperative durotomy , and postoperative epidural steroid injection . based on the results of this study , our results suggested that higher bmi are not likely to encounter heightened morbidity in lumbar microdiscectomy . Output:	objectivethe purpose of this study was to evaluate the effect of patients ' bod mass index ( bmi ) on surgical outcomes following one - level lumbar microdiscectomy.methodsfrom june 2003 to march 2007 , 129 patients underwent one - level lumbar microdiscectomy performed at a single institution . we divided the patients into 3 groups , depending on bmi . a retrospective study was conducted among the 3 groups . the operation time , estimated blood loss ( ebl ) , postoperative hospital day , recurrent disc herniation , intraoperative durotomy , and postoperative epidural steroid injection were analyzed . regression models were used to predict the relationship between bmi and surgical outcomes including operation time and ebl.resultsas bmi is greater , as the operation time is longer and the ebl is more . in particular , linear regression model analysis implied that 2.35 minute in the operation time is longer and 8.89cc in ebl is more , as bmi of 1 kg / m2 is increased . no statistically relevant differences were observed for postoperative hospital day , recurrent disc herniation , intraoperative durotomy , and postoperative epidural steroid injection.conclusionthe operation time and ebl was significantly increased in obesity , but there were no differences in surgical outcomes . our results demonstrated that higher bmi are not likely to encounter heightened morbidity in lumbar microdiscectomy .
PubmedSumm118824	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: immune function is highly heritable [ 14 ] , governed from a large proportion by combination of alleles encoding functionally relevant immune - related molecules [ 57 ] . the alleles of immune genes coevolve in interaction with pathogens attacking the organism . according to the red queen hypothesis pathogens form constant pressure on host population , selecting in many cases on variability within immune genes . genetic variability underlying the selected heterogeneity in the immune function is observable in the host as allelic polymorphism , that is , a long - lasting occurrence of two or more genotypes in a population in frequencies that can not be attributed to a recurrent mutation . long - lasting polymorphism may be maintained in the human and animal host populations by balancing selection [ 1113 ] . intriguingly , this polymorphism maintained by selection may be shared across species and even between higher evolutionary lineages such as genera or rarely families [ 1418 ] . this sharing of immunologically important genetic variation may have then profound effects on the interspecific similarity of naturally occurring ranges of immune responsiveness upon specific antigen stimulation . trans - species polymorphism ( tsp ) refers to the occurrence of identical or similar alleles in related species , excluding instances where the similarity arose by convergence or introgression [ 19 , 20 ] . by definition , tsp alleles in related species are more similar in their sequences than are the alleles within individual species . tsp arises from the passage of alleles from ancestral species to descendant species by incomplete lineage sorting [ 1921 ] ( see also in figure 1 ) . generally , we distinguish two forms of tsp , neutral tsp and balanced tsp . neutral ( transient ) tsp is frequent in closely related newly diverged species and gradually disappears . thus , neutral tsp has a tendency to be widespread across loci only in a short window of time after the speciation event [ 22 , 23 ] . . this type of tsp results from balancing selection , that is , selection for variability maintenance . balanced tsp is typically long - lasting and may be maintained in immune genes for millions or even tens of millions of years [ 2426 ] . identification of balanced tsp variants is , therefore , a powerful approach to identify naturally occurring resistance alleles with application potential in human medicine as well as in animal breeding and nature conservation . the tsp concept was proposed three decades ago by klein who supported its existence by comparative evidence in major histocompatibility complex ( mhc , h2 antigen ) in mice . until present , mhc alleles from many mutually related species were sequenced and the tsp phenomenon was reported in numbers of studies in all sorts of taxa ( see supplement 1 in supplementary material available online at http://dx.doi.org/10.1155/2015/838035 ) . is tsp unique to mhc or does it represent a general evolutionary pattern masked by little endeavour paid to its investigation outside the mhc family ? in the present review we compile present evidence on tsp in human and animal immune genes and outline main directions for further evolutionary immunogenetic research . this type of selection maintains genetic variation in populations for extensive periods of time based on three possible mechanisms : ( 1 ) heterozygote advantage [ 29 , 30 ] , ( 2 ) negative frequency - dependent selection [ 31 , 32 ] , and ( 3 ) spatio - temporally fluctuating selection [ 33 , 34 ] . heterozygote advantage ( also termed overdominance ) arises when individuals heterozygous in a particular gene are able to resist the pathogen infection better than both homozygotes . in this case overdominance is well described for mhc genes in a number of species where the benefits of heterozygosity in certain loci depend on the degree of overlap in binding specificity of individual alleles [ 30 , 35 ] . negative frequency - dependent selection , in contrast , represents a mechanism where only particular genotypes provide resistance advantage in a given time . this advantage is , nevertheless , negatively linked to the allele frequencies in a population . it has been repeatedly shown that pathogens tend to infect and adapt to the most common genotypes of the host in a population , leaving out rare genotypes . rare alleles are , therefore , favoured and increase in frequency until they reach a specific equilibrium beyond which they start to be selected against . frequencies of the alleles thus oscillate in time and balanced polymorphism is maintained [ 12 , 30 ] . empiric supports come from associations of mhc alleles of susceptibility to diseases [ 30 , 35 , 36 ] . finally , fluctuating selection is based on variation in selective pressures in space and time . most pathogens are present in a limited area of distribution and their abundance change in time ( spatio - temporal fluctuations ) . this creates distinct and changing selective pressures on different host populations that may be , nonetheless , linked by migration [ 33 , 34 ] . in contrast to the negative frequency - dependent selection , in fluctuating selection the fitness value changes as a function of particular pathogen abundance and not as a function of the allele frequency itself . although there is still serious lack in empirical evidence supporting the existence of fluctuating selection , theoretical approaches suggest that this mechanism is admissible , for instance , for the maintenance of the mhc polymorphism . the three mechanisms of balancing selection are not mutually exclusive and in all perceivable combinations all may be involved in the maintenance of the balanced tsp . mhc groups several extremely polymorphic and dynamically evolving members of the immunoglobulin superfamily playing a crucial role in the adaptive immune defence against pathogens in jawed vertebrates [ 29 , 37 ] . mhc genes encode cytoplasm - membrane - bound glycoproteins which present endogenous and exogenous oligopeptides to t cells . although the strength of the association between mhc polymorphism and resistance to infectious diseases varies between species and populations [ 39 , 40 ] , the capability of certain alleles to bind certain pathogen - derived peptides is undoubtedly essential for individual survival . the type of the selection responsible for the variability maintenance linked to disease resistance may , however , not only be natural selection but also sexual selection [ 31 , 41 ] , since the two mechanisms are not mutually exclusive and both can contribute to balanced parasite - mediated polymorphism . the mhc gene family can be generally divided into two classes : mhc class i and mhc class ii . owing to their importance in the immune response and a high variability on both interspecific and intraspecific levels , traditionally , most studies dealing with tsp have focused on mhc class i and mhc class ii genes and their peptide binding regions ( pbrs ) in particular ( summarized in table 1 and figure 2 ) . mhc class i proteins consist of a transmembrane -chain composed of 1 , 2 , 3 domains and 2-microglobulin [ 29 , 30 , 38 ] . pbr is coded by exon 2 ( 1-domain ) and exon 3 ( 2-domain ) and binds shorter oligopeptide fragments ( approximately 811 amino acids in length ) originating from an intracellular pathogen or endogenous peptides . complexes of mhc class i molecules with their peptides are recognized by t - cell receptors ( tcrs ) of cd8 t cells . mhc class ii molecules , in contrast , consist of two noncovalently associated chains : chains ( 1 , 2 ) and chains ( 1 , 2 ) , encoded by two different genes termed mhc iia and mhc iib [ 30 , 32 ] . the mhc class ii pbr is formed by n - terminal domains of these molecules1 ( exon 2 ) and 1 ( exon 2 ) . opened binding groove of mhc class ii allows binding of longer peptides ( approximately 1117 amino acids in length ) originating from extracellular pathogens or intracellular pathogens inhabiting vesicular systems [ 29 , 30 ] . complexes of mhc class ii molecules with their peptides are recognized by cd4 t cells [ 29 , 38 ] . however , cross presentation of antigenic peptides enables the exposure of some mhc - class - ii - type exogenous peptides on the binding surface of mhc class i molecules , and vice versa [ 38 , 42 ] . in mhc genes tsp encompasses mainly variable exons encoding pbrs ( in mhc class i exons 2 and 3 , in mhc class ii exon 2 of both mhc iia and mhc iib genes ) that have been the targets of strong diversifying ( increasing allele numbers ) and positive ( adapting the alleles to pathogenic peptides ) selection followed by balancing selection modifying allele frequencies [ 19 , 43 ] . there are highly variable and divergent alleles which can persist as identical or nearly identical alleles within millions of years and as allelic lineages up to tens of millions of years . in contrast to pbr , non - pbr mhc domains are usually evolutionary conserved , often under purifying selection without or with minimal tsp [ 26 , 4446 ] . although evidence for tsp has been gathered from several mhc loci in mammals , birds , reptiles , amphibians , and fish indicating that tsp is a general phenomenon in mhc , the vast majority of studies focused on genotyping only the most variable exon 2 of the mhc iib genes ( table 1 and figure 2 ) . in mhc iia loci the lower number of studies reporting tsp may be explained by the general belief of their more conserved nature when compared to mhc iib genes [ 24 , 47 , 48 ] . furthermore , despite the broad range of taxa investigated , most evidence on tsp is limited to mammals ( especially primates , rodents , and even - toed ungulates ; see supplement 1 ) . time persistence of allelic lineages in mammalian classical mhc class i genes is assumed to be generally shorter than in classical mhc class ii genes [ 19 , 49 , 50 ] . for instance , in primates mhc class i allelic lineages hla - a , -b , -c are probably younger than 22 million years [ 19 , 49 ] . in contrast , some allelic lineages in primate mhc class ii appear to be older than 30 million years . in lemuriformes identical mhc class ii alleles of drb exon 2 persist for more than 3742 million years . similarly , in dqa genes in rodents , the oldest alleles are maintained for at least 48 million years . interestingly , tsp is maintained in fish , amphibians , and reptiles on much longer timescales than in mammals [ 45 , 5355 ] . for instance , the oldest allelic lineages of exon 2 mhc ia that are shared between salmoniformes and cypriniformes precede the taxa divergence and persist for more than 145 million years . the oldest reported tsp then concerns antigen presenting mhc class i within acipenseriformes , with time persistence of 187 million years . the existence of high genetic variability and tsp in heavy chains of immunoglobulins in rabbits and hares has been predicted by serological cross reactivity among serotypes as early as in 1980s . heavy chains of immunoglobulins are encoded by the immunoglobulin variable region heavy chain ( igvh ) genes . variability in these genes may affect the binding specificity of antigen binding sites of antibodies . apart from igvh genes directly involved in vdj arrangements , other igvh genes including pseudogenes can serve as a source of variation for gene conversion . it has been shown that the igvh tsp in the leporid lineage concerns the vh1/vha gene and predates the rabbit and hare divergence and persists for at least 1624 million years , perhaps as long as for 50 million years [ 58 , 60 , 61 ] . another example of tsp in the immunoglobulin superfamily has been reported among eight macaque species in exon 2 of the c constant region of iga heavy chain [ 62 , 63 ] . although previously considered as conservative , high interspecific as well as intraspecific variability has been discovered in primates [ 6264 ] . exon 2 encodes the hinge region which lies at the base of the heavy chain regions of immunoglobulin [ 62 , 63 ] . variability in the hinge region associated with variation in flexibility of the molecule might affect the spectrum of antigens recognised by the antigen binding site of the iga antibody or allow avoidance of the attacks of bacterial proteases in this region [ 62 , 65 ] . psmb8 ( proteasome subunit -type 8 gene , lmp7 ) encodes immunoproteasomal catalytic subunit of -ring which is involved in the cleavage of peptides processed for presentation on mhc class i molecules . this gene is located in mhc class i gene cluster , and together with another proteasomal gene psmb9 its expression is interferon - induced . polymorphism in this gene involves amino acid position 31 that affects the catalytic function of the subunit . two functionally distinct allelic lineages differing at this position have been distinguished in various vertebrate lineages : ( 1 ) a - type psmb8 having ala / val at the position 31 with a larger and opened s - pocket allowing the cleavage of aromatic amino acids with the chymotrypsin activity and ( 2 ) f - type psmb8 having phe / tyr at the position of 31 with a narrower s - pocket suitable for elastase cleavage of small hydrophobic amino acids . this type of tsp has been reported in psmb8 in bony fish of the oryzias genus , where two highly diverged allelic lineages differing in the sequence encoding the s - pocket ( called here psmb8n and psmb8d ) persist for at least 3060 million years . a similar pattern has also been reported among clawed frog ( xenopus ) species suggesting the existence of similar independent tsp allelic lineages in amphibians for 80 million years . intriguingly , allelic dichotomy in psmb8 gene between cypriniformes and salmoniformes ( psmb8f and psmba ) suggests extremely long - term transorder polymorphism maintained for more than 300 million years . to conclude , these examples demonstrate long - term tsp in lower taxonomic units ( oryzias , xenopus and between salmoniformes and cypriniformes ) in genetic traits that most probably converged between major vertebrate lineages [ 67 , 70 ] . host defence peptides ( hdps , also known as antimicrobial proteins ) are small , diverse , and evolutionary conserved effector molecules involved mainly in pathogen killing [ 71 , 72 ] , but also in immunomodulation , wound healing , cell development , and so forth [ 73 , 74 ] . there are many types of hdps in all sorts of organisms , and hdp intraspecific sequence variability maintained by balancing selection has been reported [ 76 , 77 ] . in hdps , tsp has been documented so far only in avian -defensin avbd12 gene . intraspecific polymorphism in -defensin genes affects susceptibility to pathogens , such as hiv . in avbd12 gene tsp was described in exon 3 in two passerine species : blue tits and great tits . given the limited sampling effort more widespread occurrence of tsp in hdps can not be excluded . trim5 ( tripartite motif protein 5 , -isoform ) is the longest isoform of a viral restriction factor which interacts with viral capsid proteins in cytosol during retrovirus infection and thus prevents reverse transcription [ 80 , 81 ] . similarly to mhc genes , trim genes are highly polymorphic and their evolution has been driven by gene loss , pseudogenization , duplication , and punctuated positive selection [ 80 , 82 ] . trim5 consists of c - terminal spry / b30.2 domain , ring domain , and b - box2a and coiled - coil ( cc ) . tsp is documented among macaques in the spry / b30.2 domain and among biting midges ( ceratopogonidae ) in the cc domain . the variability in spry / b30.2 domain determinates restriction specificity , while the functional significance of the polymorphism in cc domain still remains unresolved [ 80 , 82 ] . in addition to the tsp in coding region of the gene , tsp has also been detected in intron 1 , apparently maintained between humans and chimpanzees by balancing selection for 47 million years . oligoadenylate synthetases ( oass ) are interferon - inducible enzymes with pleiotropic functions involved in the organism protection against retroviral infections . after activation by interferons the rna - dependent 2,5-oas synthesizes 2,5-oligoadenylates from adenosine triphosphate , which activates latent endoribonuclease rnase l leading to degradation of dsrna and inhibition of viral replication . in mice , the variability in gene oas1b has functional consequences on variation in resistance against flavivirus infections , for example , to west nile virus [ 85 , 86 ] . species of palearctic mice share two deeply diverged allelic lineages of oas1b predating the split of house mouse ( mus musculus ) and servant mouse ( m. famulus ) 2.8 million years ago . both groups of allelic lineages provide resistance to flavivirus infections ; however , the lineage of major resistance alleles protects against a broader spectrum of flavivirus genotypes compared to this tsp appears to involve only the c - terminal domain of oas1b which is responsible for the enzyme tetramerization and protein - protein binding . in contrast , the oas1 tsp known in humans , chimpanzees , and gorillas concerns the n - terminal rna - binding region . although presently most studies dealing with tsp have concentrated only on the mhc loci ( mhc i and mhc ii and their peptide binding regions , in particular ) , the few examples described in other immune genes suggest that tsp is a common and general evolutionary phenomenon . indeed , besides immune genes , the tsp has been documented , for example , in self - incompatibility loci preventing self - fertilization in angiosperms [ 8991 ] , in mating loci in fungi [ 9294 ] , in abo blood system in primates [ 9597 ] , or in complementary sex determiner gene in hymenoptera [ 98 , 99 ] . investigation of tsp predominantly in association with mhc thus appears to be a historically given stereotype which might have slowed down the rate of similar investigation in other families of immune genes . it has been recently proposed for humans - chimpanzees that tsp is especially common in membrane glycoproteins . as shown in the present review , tsp may be present in genes encoding effector molecules as well as immune receptors . the products of both gene types physically interact with pathogen molecules and are , therefore , more likely than others to evolve under balancing selection . further research should clearly focus more intensively on investigation of tsp patterns in innate immune genes . it has been proposed recently that at least approximately half of the genetic variability for resistance to infection is attributable to non - mhc genes . we suggest that besides antimicrobial peptides , oligoadenylate synthetases , or viral restriction factors where the first evidence of tsp has been reported , further effort should be made to reveal tsp in pattern recognition receptors ( prrs ) . prrs are innate immunity receptors that recognize pathogen - associated molecular patterns ( pamps ) that serve as danger signals . considering the direct physical association between prrs and pamps in triggering the immune response , in concordance with the red queen hypothesis we may predict strong evolutionary pressures maintaining balanced frequencies of prr alleles . there are many families of prrs , toll - like receptors ( tlrs ) , c - type lectin receptor ( clrs ) , rig - like receptors ( rlss , retinoic acid - inducible gene - i - like receptors ) , nod - like receptors ( nlrs , nucleotide - binding oligomerization domain receptors ) , and others [ 102 , 104 ] . despite the fact that prrs are evolutionary relatively conserved , considerable nonsynonymous polymorphism with predicted functional significance has been recently documented in the binding sites of these receptors both on interspecific and intraspecific levels [ 105109 ] . recent comparison of human populations also revealed that balancing selection is the main force shaping the evolution of many innate immunity genes . although commonly assessed in gene coding regions , tsp may also be maintained in other functionally important parts of the genome , such as , for example , the promoter regulatory sequences of individual genes . it has been reported in primates that tsp may preferentially involve transcription factor binding sites regulating gene expression [ 100 , 111 ] . our knowledge on tsp in noncoding regions is currently insufficient and further research is needed to show how widespread this type of tsp is . when studying patterns of polymorphism on interspecific level , some caution is also needed before tsp is assigned and reported . several evolutionary mechanisms other than balanced tsp were also proposed to explain the existence of shared polymorphism in several related taxa . these are , namely , ( 1 ) incomplete lineage sorting by chance ( sometimes described as neutral or transient tsp as described in the introduction ) , ( 2 ) convergent evolution , and ( 3 ) genetic introgression . distinguishing these mechanisms from tsp is one of the greatest challenges in the present tsp research [ 112 , 113 ] ( see also figure 1 ) . in contrast to balanced tsp and incomplete lineage sorting by chance ( which is a state expected mainly in newly diverged species ) , convergent evolution is a process whereby organisms ( related or not ) independently evolve similar traits as a result of adaptation to similar environments or ecological niches [ 20 , 32 ] . although presumably common in immune genes [ 32 , 51 , 114 ] , convergence has been shown difficult to detect . convergent evolution usually operates in short functionally important motifs and may be , therefore , distinguished from tsp by specific coding resemblance only in these key regions . comparison of phylogenetic trees constructed based on regions with a distinct function ( e.g. , peptide - binding region , pbr , sequence and non - pbr sequence of mhc ) may be used to differentiate between tsp and convergence [ 26 , 51 , 114 ] . also the third mechanism that may be mistaken with tsp , that is , hybridization with subsequent adaptive introgression , may be far more common than generally assumed . introgression occurs mainly in evolutionary young , radiated , or closely related species with incomplete reproductive isolation mechanisms , which further complicates its differentiation from tsp . mixing alleles of the both trans - specific and hybrid origin ( that are barely distinguishable ) have been reported in adaptive radiated species , in darwin finches [ 115 , 116 ] or cichlid fish of haplochromis species flock of east african lakes . there is still lack of evidence to show how common is the hybridization - linked adaptive introgression in immune genes ( but see , e.g. , [ 14 , 112 , 113 , 118120 ] ) . one of the possible ways to distinguish between adaptive introgression and tsp is to compare the relative size of the haplotype blocks of the shared polymorphism . in case of tsp we expect these blocks to be smaller than in case of the gene introgression [ 113 , 118 , 119 ] . combining large data sets with novel genomic approaches such as the highly dense snp chips or next - generation sequencing may be useful in doing so . not only basic evolutionary research but also human and veterinary medical research may benefit from precise identification of tsp . in addition to the clear potential of tsp to identify functionally important variation in human and animal genomes ( that may be associated with disease susceptibility or resistance ) , tsp alleles may also be linked to deleterious mutations accumulated in the neighbourhood of the sites maintained by the balancing selection . identification of beneficial and deleterious variability in genomes is essential precondition allowing complex personalised medicine in the future . taken all together , despite its importance and general applicability , in recent research the tsp concept is being commonly associated only with mhc trans - specific genetic variation . this research stereotype is unfortunate , since lacking evidence on tsp in other types of immune genes precludes our understanding of the mechanisms shaping the present genetic variability maintained by host - pathogen coevolution . besides focusing on tsp in innate immunity genes ( and mainly prrs ) , more effort should also be made to distinguish true tsp from tsp - like patterns . although originally a question of an academic interest , tsp investigation may bring practically relevant results . identification of tsp variants is a powerful approach to identification of naturally occurring resistance alleles with application potential in human and veterinary medicine , animal breeding , and nature conservation . recent advance of genomics in immunology allows us systematic research of tsp in all sorts of immune genes and perceiving the tsp concept as a mhc - linked mechanism would jeopardise the interpretational potential of the current immunogenetic research . Output:	immunity exhibits extraordinarily high levels of variation . evolution of the immune system in response to host - pathogen interactions in particular ecological contexts appears to be frequently associated with diversifying selection increasing the genetic variability . many studies have documented that immunologically relevant polymorphism observed today may be tens of millions years old and may predate the emergence of present species . this pattern can be explained by the concept of trans - species polymorphism ( tsp ) predicting the maintenance and sharing of favourable functionally important alleles of immune - related genes between species due to ongoing balancing selection . despite the generality of this concept explaining the long - lasting adaptive variation inherited from ancestors , current research in tsp has vastly focused only on major histocompatibility complex ( mhc ) . in this review we summarise the evidence available on tsp in human and animal immune genes to reveal that tsp is not a mhc - specific evolutionary pattern . further research should clearly pay more attention to the investigation of tsp in innate immune genes and especially pattern recognition receptors which are promising candidates for this type of evolution . more effort should also be made to distinguish tsp from convergent evolution and adaptive introgression . identification of balanced tsp variants may represent an accurate approach in evolutionary medicine to recognise disease - resistance alleles .
PubmedSumm118825	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: inflammation is a natural protective mechanism that resolves infections and injuries of the target tissue . failure to effectively resolve the inflammation and return the affected tissue to homeostasis leads to maladaptation and precipitation of pathophysiologic consequences that often result in the development of chronic maladies , including cardiovascular diseases and diabetic complications . , it has been well established that injury - elicited inflammation in the vasculature often causes excessive proliferation of vascular smooth muscle cells within vessel walls and the subsequent expansion of the intima , leading to the eventual blockage of the vessel . although effective in combating neointima hyperplasia , current anti - inflammatory and antimitotic drugs often display significant side effects and toxicity that deem systemic applications unfeasible , and their local delivery is achieved via drug - eluting stents . , therapeutic reagents that can be administered systemically stand the benefit of providing alternative avenues for treating acute vascular injuries as well as circumventing overall chronic inflammation in the vasculature . rage is a pattern recognition receptor that recognizes multiple endogenous ligands and triggers innate and adaptive immune responses . , , , , signaling via rage has been associated with vascular inflammation and implicated in the development of cardiovascular diseases . , prior studies , have shown that administration of srage can protect against injury - mediated vascular inflammation and neointimal expansion by functioning as a rage decoy . such protection by srage , our recent study demonstrated that n - glycoform modifications of srage modulate its bioactivity : compared with srage produced in insect sf9 cells used in previous studies ( ie , 5 g / g body weight , daily injection for a week ) , a single , low dose of srage produced in chinese hamster ovary cells ( srage ) ( ie , 3 ng / g body weight ) can substantially reduce neointima growth and inflammation in a rat carotid balloon injury model . these findings render srage an attractive therapeutic candidate with clinical potential . , although previous studies assessed how srage treatment affected neointimal growth via histomorphologic analyses of postmortem vessel sections , , , direct assessment of srage action in vivo has not been performed . vessel ultrasound sonography is a technique that can be used noninvasively in clinical practice to monitor arterial structure and function . , , to further validate srage efficacy to suppress neointimal growth , and to provide a basis for future clinical applications , we performed sonograph studies on carotid balloon denudation - injured rats before histology and compared these results with those observed in histomorphologic analyses . such studies render an independent assessment of srage efficacy in vivo , and can validate its potential as a candidate therapeutic protein for treating vascular injury and inflammation . male wistar rats ( 400450 g ) were purchased from charles river laboratories ( wilmington , massachusetts ) and maintained in a vivarium fed the national institute on aging on ad libitum food diet ( nih-07 mouse / rat diet ; national institutes of health , bethesda , md ) with access to filtered water . the surgical procedure and postsurgery care have been described in detail , and have been in compliance with the national institutes of health s guide for the care and use of laboratory animals ( nih publication no . 3040 - 2 , revised 1999 ) , and with the institutional animal care and use committee approved protocol . immediately following the surgery , generation of srage , srage , and srage(n25t / n81 t ) expression vectors , as well as purification of srage recombinant protein have been described in detail . vessel ultrasound sonography was conducted on the 0 day ( ie , surgery day , before surgery ) , and on the seventh and 14th day postsurgery . rats were sedated with isoflorane ( 2% in oxygen ) via facemasks , and put in the supine position . after shaving frontal neck skin hair , an m - mode tracing was recorded at 3 points in the long - axis view : 3 and 10 mm distal to the base , and 2 mm proximal to the bifurcation . the vessel wall thickness and lumen diameter at minimal and maximal points were measured using national institutes of health image j software . the parameters from the nonoperated right carotid artery of the same rat were used as control . parameters from the nonoperated right side of the carotid artery of the same subjects were used as the normal control relative to the balloon - injured left side of the carotid artery . allocation concealment was applied to balloon denudation surgery , sonographic studies , and histomorphologic analyses . investigators involved in the procedure were also blinded in respect to srage types and dose administered . male wistar rats ( 400450 g ) were purchased from charles river laboratories ( wilmington , massachusetts ) and maintained in a vivarium fed the national institute on aging on ad libitum food diet ( nih-07 mouse / rat diet ; national institutes of health , bethesda , md ) with access to filtered water . the surgical procedure and postsurgery care have been described in detail , and have been in compliance with the national institutes of health s guide for the care and use of laboratory animals ( nih publication no . 3040 - 2 , revised 1999 ) , and with the institutional animal care and use committee approved protocol . immediately following the surgery , rats were administered the designated dose of srage via intraperitoneal injection . generation of srage , srage , and srage(n25t / n81 t ) expression vectors , as well as purification of srage recombinant protein have been described in detail . vessel ultrasound sonography was conducted on the 0 day ( ie , surgery day , before surgery ) , and on the seventh and 14th day postsurgery . rats were sedated with isoflorane ( 2% in oxygen ) via facemasks , and put in the supine position . after shaving frontal neck skin hair , an m - mode tracing was recorded at 3 points in the long - axis view : 3 and 10 mm distal to the base , and 2 mm proximal to the bifurcation . the vessel wall thickness and lumen diameter at minimal and maximal points were measured using national institutes of health image j software . the parameters from the nonoperated right carotid artery of the same rat were used as control . parameters from the nonoperated right side of the carotid artery of the same subjects were used as the normal control relative to the balloon - injured left side of the carotid artery . allocation concealment was applied to balloon denudation surgery , sonographic studies , and histomorphologic analyses . investigators involved in the procedure were also blinded in respect to srage types and dose administered . our previous studies had demonstrated that administration of srage immediately after arterial injury is most therapeutically effective . to monitor srage effects in live rats with carotid arterial injury , we performed the ultrasound sonography procedure on rats before the surgery , and at 1 and 2 weeks postsurgery . although at 1 week postsurgery the maximal vessel lumen diameter of injured vessels treated by srage is clearly distinguishable from that of placebo - treated vessels ( figure 1a ) , the measurement of average vessel wall thickness of these 2 groups was not clearly differentiated until 2 weeks postsurgery ( figure 1b ) , suggesting that sufficient time ( ie , at least 1 week ) is required to assess the benefits of srage treatment in a live animal model . to test the correlation of sonographic data with that obtained from postmortem histologic measurement , we plotted the data from the 2 independent measurements , using the lowest effective dose ( ie , 0.5 ng / g body weight ) . despite the shrinkage of vessel cross - sections during the histologic process , reasonably high correlations between the data from the 2 measurements were apparent in the scatter plots ( lumen diameter : r = 0.72 ; vessel wall thickness : r = 0.76 ) ( figure 2a and 2b ) , suggesting that the effect of srage treatment can be independently , and perhaps reliably monitored in vivo ( figure 2c ) . on the basis of timing and correlation with histologic results shown in figure 1 , figure 2 , we also measured lumen diameter and vessel wall thickness at 2 weeks postsurgery in rats treated with srage at lower ( 0.51.5 ng / g body weight ) ( figure 3a and 3b ) and higher doses ( 1.56 ng / g body weight ) ( figure 3c and 3d ) . when vessel wall thickness was measured , 1.5 ng / g and higher doses of srage treatment appeared to be statistically similar to those of nonoperated vessels ( figure 3a and 3c ) . however when lumen diameter was measured , dose - dependent improvement in groups treated with 0.5 to 3 ng / g srage was detected ( figure 3b and 3d ) , suggesting that the latter parameter may be more sensitive . our previous work showed that specific n - glycoform modifications are a key determinant of srage bioactivity , and that not only n - glycosylation , but also mammalian cell - specific , complex - type n - glycosylation is critical for the observed high therapeutic efficacy of srage . independent assessment using sonography ( figure 4 ) with an established optimal dose of srage further confirmed a significantly higher efficacy of srage relative to that of nonglycosylated srage ( n25t / n81 t ) and srage produced in insect sf9 cells . our previous studies had demonstrated that administration of srage immediately after arterial injury is most therapeutically effective . to monitor srage effects in live rats with carotid arterial injury , we performed the ultrasound sonography procedure on rats before the surgery , and at 1 and 2 weeks postsurgery . although at 1 week postsurgery the maximal vessel lumen diameter of injured vessels treated by srage is clearly distinguishable from that of placebo - treated vessels ( figure 1a ) , the measurement of average vessel wall thickness of these 2 groups was not clearly differentiated until 2 weeks postsurgery ( figure 1b ) , suggesting that sufficient time ( ie , at least 1 week ) is required to assess the benefits of srage treatment in a live animal model . to test the correlation of sonographic data with that obtained from postmortem histologic measurement , we plotted the data from the 2 independent measurements , using the lowest effective dose ( ie , 0.5 ng / g body weight ) . despite the shrinkage of vessel cross - sections during the histologic process , reasonably high correlations between the data from the 2 measurements were apparent in the scatter plots ( lumen diameter : r = 0.72 ; vessel wall thickness : r = 0.76 ) ( figure 2a and 2b ) , suggesting that the effect of srage treatment can be independently , and perhaps reliably monitored in vivo ( figure 2c ) . on the basis of timing and correlation with histologic results shown in figure 1 , figure 2 , we also measured lumen diameter and vessel wall thickness at 2 weeks postsurgery in rats treated with srage at lower ( 0.51.5 ng / g body weight ) ( figure 3a and 3b ) and higher doses ( 1.56 ng / g body weight ) ( figure 3c and 3d ) . when vessel wall thickness was measured , 1.5 ng / g and higher doses of srage treatment appeared to be statistically similar to those of nonoperated vessels ( figure 3a and 3c ) . however when lumen diameter was measured , dose - dependent improvement in groups treated with 0.5 to 3 ng / g srage was detected ( figure 3b and 3d ) , suggesting that the latter parameter may be more sensitive . our previous work showed that specific n - glycoform modifications are a key determinant of srage bioactivity , and that not only n - glycosylation , but also mammalian cell - specific , complex - type n - glycosylation is critical for the observed high therapeutic efficacy of srage . independent assessment using sonography ( figure 4 ) with an established optimal dose of srage further confirmed a significantly higher efficacy of srage relative to that of nonglycosylated srage ( n25t / n81 t ) and srage produced in insect sf9 cells . the therapeutic value of srage has been well recognized and tested in various animal models , including arterial injury models . , , , administration of srage , a decoy of rage , can reduce injury - associated , rage signal - mediated chronic inflammation and minimize maladaptation and remodeling in vasculature , thus decreasing the risk of cardiovascular diseases and other vessel - associated complications . although previous studies discovered that srage can be used to block neointimal growth and formation of atherosclerotic plaques in animal models , to achieve the blockage , a high dose and multiple administrations of srage produced in insect sf9 cells were employed . , , , , our recent study demonstrated that specific n - glycoform modifications are the key determinant underlying srage bioactivity and therapeutic efficacy : a low , single dose of srage produced in cho cells can significantly reduce injury - associated inflammation and neointimal growth . in addition to the observed low efficacy , glycoforms from insect cells are also immunogenic in mammals , and therapeutic glycoproteins must be produced from mammalian sources . previous studies , including ours , had evaluated therapeutic effects of srage mainly based on postmortem histomorphologic analyses of the vessel cross - sections and in vitro bioactivity assays . although these assessments , especially histologic studies , provided important and direct information of the vessel condition , including inflammation and formation of the neointima , these approaches can not be used for clinical evaluation of treatment . the present study demonstrates that injury of the vessel as well as the therapeutic effects of srage can be independently evaluated via vessel sonographic assessment . similar to the results obtained from histology shown in our previous study , current sonographic studies also showed a degree of dose - dependent attenuation of vessel lumen diameter , although this was less apparent in measured vessel wall thickness ( figure 3 ) . consistent with histology , sonography also showed that paucimannose - glycan modified srage and the nonglycosylated srage(n25t / n81 t ) were ineffective when used in the same dose ( 3 ng / g ) as srage ( figure 4 ) . previous studies , showed that srage administered immediately after arterial injury was most effective to restrict neointimal expansion . the manifested beneficial effects of srage are not readily detectable in vivo until at least 1 week after surgery and treatment , and the therapeutic outcome becomes apparent 2 weeks after surgery and treatment ( figure 1 ) . these observations suggest that blocking rage alarmin ligands immediately after injury circumvents rage - mediated inflammatory signaling , and allows the injured vessel to undergo a repair process with less , or controlled , inflammation leading to a healing course with reduced remodeling . compared with our previously published histology results , vessel ultrasound sonography appears to be less sensitive to discern the difference between nonoperated vessels and vessels operated on with treatment when a higher dose of srage ( 3 ng / g ) was used ( figure 4a ) , whereas such difference was discernable by histology . when a lower dose of srage was used ( 0.5 ng / g ) , the difference between treated and nonoperated vessels is clearly discernable and there was a better correlation between sonography and histology ( figure 2 ) . this is likely due to the fact that 0.5 ng / g is not an optimal dose , and that remodeling of the vessel wall by balloon denudation was not suppressed as much as that in a situation when a higher dose was administered . these observations suggest that sonographic data should serve as a reference for application , and that the exaggerated benefits observed in higher srage doses should be taken into consideration to determine a proper dose for the best treatment outcome . our research using vessel sonography to monitor srage effects in live rats reaffirmed that specific n - glycoform - modified srage , produced in cho cells is highly effective in vivo to attenuate neointimal growth after arterial injury , compared with that produced in insect cells . this in vivo approach also provides a basis for monitoring srage effects in future clinical applications . the authors have indicated that they have no conflicts of interest regarding the content of this article . Output:	objectivewe aimed to assess the therapeutic efficacy of differentially modified soluble receptor for advanced glycation end products ( srage ) in vivo using vessel ultrasound sonography and to compare the sonography data with those from postmortem histomorphologic analyses to have a practical reference for future clinical applications.methodsvessel ultrasound sonography was performed in a srage - treated rat carotid artery balloon injury model at different time points after the surgery , and therapeutic efficacy of different doses of srage produced in chinese hamster ovary cells and with different n - glycoform modifications were assessed.resultsvessel ultrasound sonography found that srage produced in chinese hamster ovary cells with complex n - glycoform modifications is highly effective , and is consistent with our recent findings in the same model assessed with histology . we also found that sonography is less sensitive than histology when a higher dose of srage is administered.conclusionssonograph results are consistent with those obtained from histology ; that is , srage produced in chinese hamster ovary cells has significantly higher efficacy than insect cell - originated srage cells .
PubmedSumm118826	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: fine needle aspiration cytology ( fnac ) is useful in the diagnosis and triage of skin adnexal tumors . however , there is limited literature on the fnac of skin adnexal tumors , including eccrine spiradenomas . herein , we present a rare case of a young lady , presenting with multiple subcutaneous nodules in her left shoulder , initially misdiagnosed as an ewing sarcoma ( es ) on fnac smears , elsewhere . a 28-year - old lady presented with multiple , subcutaneous supraclavicular swellings , associated with intermittent pain of one and half - year duration . she did not have any other significant medical , surgical , or family history . on clinical examination , there were multiple , subcutaneous discrete - to - confluent , firm , nonmobile , slightly tender nodular lesions in her left shoulder , fixed to the underlying structures . subsequently , she underwent a core needle biopsy from the various nodules . magnetic resonance imaging ( mri ) revealed multiple , discrete , and confluent rounded , enhancing nodular lesions within the skin and subcutaneous fat in her left supraclavicular region , located posteriorly over the trapezius muscles and superficial fascia . post - contrast , these lesions showed moderate inhomogeneous enhancement with smooth margins [ figure 1 ] . ( a ) post - contrast mri displaying multiple , discrete - to - confluent lesions ( arrow ) over the left shoulder . ( b ) fnac smears showing cohesive cluster of cells with round - to - oval nuclei and scant cytoplasm , including relatively darker , smaller nuclei at the periphery , along with interspersed metachromatic / pink hyaline droplets ( mgg , 200 ) . ( c ) higher magnification displaying rosetting arrangement of tumor cells around hyaline droplet ( mgg , 400 ) . ( d ) cluster of bland cells , including cells with pale and dense chromatin , forming rosette - like structures ( h&e , 400 ) fluorodeoxyglucose ( fdg ) f18 positron emission tomography ( pet ) computed tomography ( ct ) scan showed low - grade metabolic uptake in the left supraclavicular subcutaneous nodules ( suv max 2.25 ) . smears were moderately cellular , comprising cohesive clusters and acinar - rosetting arrangement of cells with round - to - oval nuclei and scant cytoplasm , along with cells containing relatively darker nuclei and few scattered lymphocytes , against a background of red blood cells ( rbcs ) . interspersed were stromal matrix cores that appeared as spherical hyaline droplets / bodies . microscopic sections revealed multiple , sharply defined basophilic tumor nodules in the dermis , extending into the subcutis and unattached to the overlying epidermis , comprising round - to - oval cells arranged in acinar , cord - like , trabecular , and diffuse arrangements . focal lumen formations were noted . there were two types of cells , including small dark basaloid cells with relatively dense nuclear chromatin towards the periphery ( myoepithelial cells ) and larger cells with pale nuclei closer towards the lumens . interspersed were numerous hyaline droplets / pink bodies that were periodic acid schiff ( pas ) positive , as well as diastase resistant , along with scattered lymphocytes [ figure 2 ] . ( b ) tumor comprising round - to - oval cells surrounding pink hyaline bodies . ( c ) dual population of small , dark , and relatively large , tumor cells with vesicular chromatin , around hyaline bodies . ( d ) tumor cells arranged in tubular and trabecular arrangement , including cells with pale chromatin toward lumens and relatively darker myoepithelial cells toward the periphery . scattered lymphocytes noted ( h&e , 200 ) by immunohistochemistry , the relatively pale cells towards the lumens displayed strong positivity for ck7 tumor cells were negative for carcinoembryogenic antigen ( cea ) ( monoclonal col1 ) and displayed weak c - kit / cd117 immunostaining . ( dab , x400 ) ( b ) s100-p positivity within tumor cells ( dab , 400 ) . ( e ) tumor cells displaying weak cd117/c - kit positivity ( dab , 400 ) smears were moderately cellular , comprising cohesive clusters and acinar - rosetting arrangement of cells with round - to - oval nuclei and scant cytoplasm , along with cells containing relatively darker nuclei and few scattered lymphocytes , against a background of red blood cells ( rbcs ) . interspersed were stromal matrix cores that appeared as spherical hyaline droplets / bodies . microscopic sections revealed multiple , sharply defined basophilic tumor nodules in the dermis , extending into the subcutis and unattached to the overlying epidermis , comprising round - to - oval cells arranged in acinar , cord - like , trabecular , and diffuse arrangements . focal lumen formations were noted . there were two types of cells , including small dark basaloid cells with relatively dense nuclear chromatin towards the periphery ( myoepithelial cells ) and larger cells with pale nuclei closer towards the lumens . interspersed were numerous hyaline droplets / pink bodies that were periodic acid schiff ( pas ) positive , as well as diastase resistant , along with scattered lymphocytes [ figure 2 ] . ( b ) tumor comprising round - to - oval cells surrounding pink hyaline bodies . ( c ) dual population of small , dark , and relatively large , tumor cells with vesicular chromatin , around hyaline bodies . ( d ) tumor cells arranged in tubular and trabecular arrangement , including cells with pale chromatin toward lumens and relatively darker myoepithelial cells toward the periphery . scattered lymphocytes noted ( h&e , 200 ) by immunohistochemistry , the relatively pale cells towards the lumens displayed strong positivity for ck7 tumor cells were negative for carcinoembryogenic antigen ( cea ) ( monoclonal col1 ) and displayed weak c - kit / cd117 immunostaining . ( dab , x400 ) ( b ) s100-p positivity within tumor cells ( dab , 400 ) . ( e ) tumor cells displaying weak cd117/c - kit positivity ( dab , 400 ) fnac is useful in the diagnosis and triage of skin adnexal tumors , considering these tumors invariably present as superficial lesions , which is accessible for fnac . the present case is the first report of multiple eccrine spiradenomas , identified as an challenge exists in differentiating adnexal tumors from their mimics on cytology , as noted in the present case , which was initially misdiagnosed as es . earlier , a pilomatrixoma was reported to be misdiagnosed as a round cell tumor on cytology . therefore , knowledge of clinical and cytopathologic features , along with histopathologic and immunohistochemical features of skin adnexal tumors , leading to their correct diagnosis by a holistic approach is crucial . nearly 5 cases describing cytopathological features of an eccrine spiradenoma have been reported [ table 1 ] . most of these have been reported in adult female patients , presenting with painful nodules , similar to the present case . on cytologic examination , presence of small hyaline bodies reminiscent of stromal matrix and basement membrane material within cohesive clusters of banal , round to oval cells , including relatively darker , myoepithelial cells and scattered lymphocytes constituted as diagnostic clues for a skin adnexal tumor , over es , even though both tumors display round cells with rosette formations . while diagnosis of an adnexal tumor can be made on fnac smears , its subcategorization is difficult , in view of overlapping morphological features . epithelial cells admixed with pink fibrillary material , and calcium deposits are identified in a pilomatrixoma . presence of epithelial cells , along with myoepithelial cells and scattered lymphocytes , are observed in an eccrine spiradenoma , in contrast to monomorphic cells that are more associated with an adenoid cystic carcinoma . . literature review of reported cases of eccrine spiradenoma on cytology diagnosis of an adnexal tumor in the present case prompted a biopsy from various nodules that the confirmed diagnosis of eccrine spiradenomas . histopathologically , cylindromas display jigsaw puzzle arrangement of tumor cells , whereas eccrine spiradenomas occur as multiple dermal and subcutaneous lobules . moreover , multiple eccrine spiradenomas are relatively more common than cylindromas that rarely occur in the form of multiple lesions in scalp location ( turban tumors ) . possibility of a malignant eccrine spiradenoma in this case was less likely because the biopsy cores were accessed from all the representative lesions and none of the tumor nodules on histopathological examination revealed features of malignancy . ck7 positivity in the luminal cells , seen in both eccrine spiradenomas and cylindromas , reinforced tumor origin from the secretory coil . similar to kolda et al . , we did not observe cea positivity with the clone col-1 . in addition , we observed cd117/c - kit positivity that is documented in 43% eccrine spiradenomas . another study has unravelled that spiradenoma and cylindroma originate from hair follicle bulge and not from the eccrine sweat gland because both these tumors were found to significantly express cd200 that is a stem cell marker involved in basal bulge cells . to summarize , careful attention toward clinicoradiological and cytopathologic features is useful in diagnosing rare adnexal tumors , such as multiple eccrine spiradenoma , using fnac . correct diagnosis in the present case helped in obviating a radical surgery and adjuvant chemotherapy that constitutes the treatment for es . despite recommendation for a surgical resection , unfortunately , our patient was lost to follow - up . Output:	a 28-year - old lady presented with multiple swellings in her left shoulder , associated with intermittent pain since last one and a half years . radiologic imaging revealed multiple , well - defined , subcutaneous lesions in her left supraclavicular region . fine needle aspiration cytology ( fnac ) smears were initially reported as ewing sarcoma , elsewhere . on review , the smears showed cohesive clusters of round - to - oval cells with scant cytoplasm , which were focally arranged in an acinar - rosetting pattern around hyaline droplets / bodies , along with few scattered lymphocytes against a background of red blood cells . the diagnosis considered was adnexal tumor . subsequent biopsy from the multiple lesions confirmed the diagnosis of eccrine spiradenoma . by immunohistochemistry , tumor cells were positive for ck7 , epithelial membrane antigen ( focally ) , s100 protein , and tyrosine - protein kinase kit(c - kit ) /cluster of differentiation ( cd117 ) . this case underscores the value of fnac in skin adnexal tumors and constitutes as the first case report of multiple eccrine spiradenomas , initially misdiagnosed as ewing sarcoma . literature review of similar reported cases with treatment implications are presented .
PubmedSumm118827	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: we report a 14 month old girl who developed early pacemaker infective endocarditis six weeks after insertion of the pacing device , and briefly discuss investigation and management . there are no other reported cases of paediatric pacemaker infective endocarditis from haemophilus parainfluenazae in the literature . in march 2007 a 14 month old girl with congenital complete heart block underwent implantation of an endocardial pacemaker into the right ventricle . six weeks after her pacemaker insertion , she presented with pyrexia , lethargy , diarrhoea , vomiting and poor fluid intake . she was pale and lethargic with a liver edge extending to 1.5 cm below the costal margin , and a grade 2/6 systolic murmur . two weeks after initial presentation she became acutely unwell , presenting in shock , with a grade 3/6 systolic murmur . cxr showed an enlarged heart with pacemaker and lead in situ ( fig 1 ) . chest x ray showing cardiomegaly with pacemaker in situ investigations showed a c - reactive protein of 275 mg / l , white cell count of 35.710/l , neutrophils 17.210/l , platelets 11110/l , and haemoglobin of 7.6g / dl . an echocardiogram showed a mobile mass attached to the pacing wire and tricuspid valve , moderate tricuspid regurgitation and a patent foramen ovale 2d echocardiography showing mobile vegetation 7.8 mm 9.6 mm gentamycin was added to the antibiotic regime . blood cultures showed a pure growth of gram negative rods later confirmed to be haemophilus parainfluenzae , sensitive to 3 generation cephalosporins and gentamycin . one week later she underwent open heart surgery under bypass for the complete removal of the infected cardiac pacemaker system ( fig . a follow - up 2d echocardiogram showed moderate tricuspid regurgitation and a small vegetation that was still present near the apical ventricular septum . if untreated pacemaker infective endocarditis is fatal . we discuss some management issues surrounding pacemaker endocarditis in children with emphasis on h parainfluenzae . one study by cohen et al , in a 20 year paediatric cohort , reports an overall incidence of 2.3% of implanted pacemakers.1 case reports of pacemaker endocarditis from h. parainfluenzae are rare . we conducted a literature search using medline ( 1950 to date ) and embase ( 1974 to date ) using the key words pacemaker , endocarditis , infection , haemophilus parainfluenzae . we found only two other case reports of pacemaker endocarditis caused by haemophilus parainflunzae , and both were in adults ( table 1).23 case reports of pacemaker endocarditis caused by haemophilus parainfluenzae haemophilus parainfluenzae is a commensal of the oral cavity and the upper respiratory tract , and belongs to a group of fastidious gram negative bacilli collectively known as hacek ( haemophilus spp , actinobacillus actinomycetemcomitans , cardiobacterium hominis , eikinella corrodens and kingella kingae ) . it is an unusual cause of device related bacterial endocarditis , the majority of which are caused by staphylococcus aureus and epidermidis . the commonest presenting feature is fever which is present in 80% of cases.4 septic shock is the presentation in only 9% of cases.5 when suspected , transthoracic echocardiography ( tte ) is an excellent tool for the detection of vegetations in children , with a reported sensitivity of 81% . transoesophageal echocardiography ( toe ) has been shown to have a superior detection rate in adults , but its role in children has yet to be established . a meta analysis by de costa et al was shown to significantly reduce the incidence of serious infective complications following pacemaker insertion.6 secondary prophylaxis is not routinely recommended , and the american heart academy still classifies this group as a negligible risk category . we could not define a clear source of infection in our patient , and can only postulate haematogenous spread from her middle ear infection . third generation cephalosporins are an excellent choice of antibiotic for hacek organisms which are often resistant to penicillins . however removal of the infected intracardiac device offers the best chance of complete eradication of the infection , with lower morbidity and mortality.78 device re - implantation should be at a new site when the patient is no longer bacteraemic . pacemaker endocarditis should always be suspected in a child with an implanted pacemaker presenting with fever . Output:	we report a case of pacemaker infective endocarditis in a 14 month old girl , caused by haemophilus parainfluenzae . there are no other cases in children reported in the literature . we discuss the issues surrounding the case and the evidence which influenced our management .
PubmedSumm118828	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: in the usa , breast cancer is the most commonly diagnosed malignancy in women . in 2010 , it is estimated that approximately 200,000 women were newly diagnosed with breast cancer and , currently , 1 in 8 women will be diagnosed within their lifetimes . the mortality picture and survival rate associated with breast cancer have been improving over the past two decades . these improvements have been reported to be related to early detection , adjuvant therapy , and radiation therapy [ 24 ] . however , despite overall improvement in survival , several reports indicate that african american ( aa ) females have poorer outcomes compared to caucasian females . data from the national cancer institute 's surveillance , epidemiology , and end results ( seer ) program indicate that age - adjusted breast cancer incidence rates in african americans are substantially lower than those from caucasian women with 141 cases per 100 000 in caucasian women and 122 in african americans [ 6 , 7 ] . although the incidence may be lower in aas , the mortality rate appears to be higher compared to caucasian women [ 810 ] . epidemiologically , aa women are diagnosed at a more advanced stage , have tumor - related characteristics that are more commonly estrogen receptor negative , and present with higher grade tumors compared to caucasian women [ 1215 ] . socioeconomically , access to health insurance , medical care , and variability in the aggressiveness of treatment have all been proposed as possible contributing factors [ 16 , 17 ] . finally , several investigations report that more aa breast cancer patients die from their medical comorbidities than from complications of their breast cancer few reports on racial disparities have investigated the role of community hospital care delivery and their effect on outcomes . we conducted a retrospective analysis of prospectively collected data from the brooklyn hospital center 's ( tbhc ) cancer registry . tbhc is an inner city , community - based teaching hospital with a high percentage of aa patients . the study was divided into two time periods , 19972004 ( period a ) and 20052010 ( period b ) . we limited our data analysis to postsurgery patients in an attempt to minimize the differences in inequality of access to medical facilities between different racial groups . our primary aim was to assess whether known and widely used clinical breast cancer biological factors would explain differences in breast cancer postsurgical survival over the two time periods . our objective was to determine if racial disparities existed and whether or not these disparities continue to exist . in addition , we sought to identify any factors associated with racial disparities that could serve as points of possible interventions at the healthcare system level . data was prospectively collected from tbhc cancer registry from 1997 to 2010 . of the 1537 registered patients , 1276 ( 79.5% ) are african americans , 281 ( 17.5% ) are white , and 42 ( 2.9% ) are asian . demographic data collected include age at diagnosis , sex , race ( self - reported ) , and insurance status . clinical data such as stage at diagnosis , tumor location , mode of diagnosis , histopathology , pathology stages , lymph nodes status , er , and pr status ( available after 2003 ) , and methods of treatment were also included . the study was divided into two time periods , 19972004 ( period a ) and 20052010 ( period b ) . baseline characteristics were compared between the two different periods and between the two racial groups . these comparisons include distribution of the histological grade , pathological stages , surgery , chemotherapy , er , and pr status . age was subdivided into three subgroups < 45 , 4560 , and > 60 for survival analysis . survival was compared between these two time periods in aa and caucasian women , respectively . based on the baseline characteristics and survival improvement between the two time periods , we compared whether there are survival disparities between the two populations . overall survival was calculated from the date of diagnosis to the data of death from any causes or the follow - up cutoff . statistical analyses were done with spss ( spss inc . , chicago , il , usa ) version 16 and epi info 3.5.3 ( center for disease control and prevention ) . chi square and fisher 's exact test were used to examine the distribution of cancer location , histological grade pathological stages , surgery versus nonsurgery , and chemotherapy versus nonchemotherapy . one - way analysis of variance ( anova ) was conducted to compare the difference in age at diagnosis between aa and caucasian women . kaplan - meier survival probabilities and multivariate cox proportional hazards models were applied to estimate hazard ratios ( hr ) with 95% confidence intervals ( 95% ci ) . the average age at diagnosis is 61.04 ( sd 13.99 ) in period a and 59.95 ( sd 13.80 ) in period b ( p > 0.05 ) . caucasian females were diagnosed at a younger age than aa in period b suggesting earlier detection ; however , no significant differences were observed ( see table 1 ) . significant differences in histological grade as well as pathology stages between the two time periods were observed . as there are approximately 21% of cell type reported as undetermined in histological grade in our registry and 10 - 11% unstaged in pathology , our data analysis was performed twice . we observed a high percentage of grades i and ii carcinomas in period a and a high percentage of grades iii and iv carcinomas in period b in the overall total population . when we analyzed the population according to race , a high percentage of high - grade differentiation was present in period b in aa compared to caucasian women . white females demonstrated more grade ii cancers in period b and more grade iii cancers in period a , suggesting earlier detection in caucasian females in the latter time period compared to aas ( see table 1 ) . we repeated our data analysis and included the cell type undetermined , which still demonstrated a high percentage of high - grade cancer in period b in aas . for the pathology stages , no significant differences between the two time periods were observed in aas and caucasian females combined together and aas alone . significant differences in breast cancer staging on presentation were observed in the caucasian group during the two time periods . a higher percentage of stage 0 and stage i cancers was observed in caucasian females in period b versus a high percentage of stage ii and stage iii cancers in period a ( p < 0.003 ) . significant difference was observed in the er / pr status with a high percentage of er positive in period b : 37/200 ( 19.0% ) compared with 46/401 ( 11% ) positive in period a ( p = 0.024 ) as well as high percentage of pr positive in the period b , 50/255 ( 20% ) compared with 34/145 ( 11 ) in period a ( p < 0.001 ) ( see table 1 ) in the overall cohort . no significant differences in caucasian females were observed in er ( p = 0.405 ) and pr ( p = 0.476 ) status in the two time periods . for aa females , a significant difference in both er ( p = 0.025 ) and pr ( p < among all the operative procedures performed , the two most common were modified radical mastectomy ( mrm ) and lumpectomy . for the mrm , there were 33.1% ( early period ) versus 31.4% ( late period ) and for lumpectomy there were 27.9% ( early period ) versus 39.1% ( late period ) . 21.6% versus 0.8% of patients had simple mastectomies during periods a and b , respectively . the percentage of patients receiving chemotherapy , radiation therapy , and hormone therapy increased in period b ( see table 2 ) . significant differences were observed in aa in all three therapies with p < 0.001 , p = 0.007 , and p = 0.018 , respectively . kaplan meier survival analysis : postsurgery survival probability significantly improved when comparing 19972004 versus 20052010 periods ( log - rank p < 0.001 ) . survival probability increased 12.25% in period b ( aa + white ) ; the increase in survival is greater in aa females than in caucasian females with an increase of 12.62% in aa compared with 11.29% in white . overall 5-year survival probabilities , survival among aa women and survival among caucasian women are compared in table 3 . during period a , 5-year survival probabilities of 75.37% , 74.53% , and 78.70% were seen among all patients , aa women and caucasian women , respectively . these probabilities increased to 87.62% , 87.15% , and 89.99% in period b. cox regression hazard ratio is 2.1824 . this postsurgery survival improvement was not affected by grade , site of tumor , and chemotherapy , but it was associated with pathology stages and number of lymph nodes removed . an increase in survival was observed between periods a and b. kaplan meier survival analysis did not demonstrate a difference in overall survival between aa ( 78.94% ) and caucasians ( 82.42% ) ( p = 0.5187 ) . however , when patient age was divided into three subgroups , a significant difference was observed in survival in patients aged 4560 years ( log - rank p = 0.05 ) , with 5 years of survival probability in african american being 86.98% and in white being 92% . this disparity is more obvious in early periods with log - rank p = 0.047 but not present in late periods ( data not shown here ) . cox hazard ratio 1.90 , 97.61% confidence , interval 3.72 , pathological stages , and the number of lymph nodes removed were associated with the prognosis ( p = 0.052 ) . however , there is no difference of the distribution in terms of the tumor grade , pathological stages , and er / pr status between african american and white in this age group ( data not shown here ) . in this retrospective , single - institution study , we found a significant improvement in survival between the two time periods in both populations . however , the baseline characteristics and treatment options that potentially contributed to the improvement are apparently different between these two ethnic groups . there is no significant difference for the age of patients at diagnosis between the two time periods . histological grade has been considered as an independent risk factor for the prediction of survival . it has been reported that aas have a higher percentage of poor grade tumors compared to caucasian females . considering the very significant survival improvement over the two time periods , we expected that the tumor would be detected in earlier tnm stages with a low - grade presentation . as undetermined tumor grades were more prevalent in period a , we can not exclude the possibility that the low number tumors with this characteristic may represent a sample bias rather than a change in tumor biology . however , our study also demonstrated that , in the early tnm stages with negative lymph nodes , histology grade was not an independent predictor for survival . so it is not a certainty that low grade is necessarily associated with a good outcome . the most recent study based on the molecular biomarker level reported that several molecules such as top2a , mcm2 , and bub1b proteins are potential molecular biomarkers of malignancy in histologically normal breast tissue and benign breast tissues may indicate a poor prognosis . we have also observed that significant differences were observed only in caucasian females with a high percentage of early stages in period b and advanced stages in period a. tnm pathology stages have been considered the most precise predictive factor for prognosis . it is not difficult to understand that with increased public awareness more and more tumors are detected in the early stages , which leads to early treatment and significant improvement in survival [ 21 , 22 ] . however , there is no significant difference in pathology stages in aa between the two time periods . a possible reason for this observation is that there is no significant change in terms of the screening rate or follow - up after screening in aa population . adams reported that aa women were 12% less likely than european american women to complete the recommended workup after mammography . this may explain why there was no significant difference observed in the pathological stages between the two time periods for aa women , suggesting that survival improvement in the aa population may be attributed to other changes . increased percentage of er and pr positive tumors was observed in period b in both aas and caucasian females . and pr positive status indicates better prognosis which can account for the survival improvement in period b. however , the correlation between er and pr status with histological grade is not clear . in our study , we observed that histological grade in period b is higher compared with period a in aa population which contrasts to the er and pr status . several studies try to identify the possible association between er and pr status with histological grade . correlation between er and pr positivity and histological grade has been reported in previous investigations [ 24 , 25 ] . er positive tumors were more likely than er negative tumors to demonstrate histological evidence of tumor differentiation , and the better - differentiated tumors rarely lacked the receptor , although this correlation was significant only in women defined as postmenopausal . however , at the molecular level , studies report that er negative breast cancers have unique characteristics : er - negative tumors show a higher expression of p53 , cerbb2 , and epidermal growth factor receptor compared to er - positive breast cancer and these unique features support the concept that er - negative tumors are a morphologically and phenotypically distinct entity , which are independent of histological grade . several molecules such as top2a , mcm2 , and bub1b proteins are reported as potential molecular biomarkers of malignancy presented in histological normal and benign breast tissues , which indicate poor prognosis . based on these studies , current new concept considered that breast cancer is a heterogeneous disease characterized by varied morphological appearances , molecular features , behavior , and difference response to therapy . based on the baseline characteristics , the factors that attributed to the improvement are different between these two groups . although surgery is considered the primary treatment for breast cancer and many patients with early stage breast cancer are cured with surgery alone , early detection through mammography , adjuvant therapy , and radiation therapy are considered the three most important factors that have contributed to overall survival improvements for the past two decades . studies indicate that adjuvant treatments have improved survival in early stages of breast cancer , metastatic breast cancer , and recurrent breast cancer . radiation therapy decreases local recurrence and improves survival as well [ 4 , 3234 ] . while there were no significant differences in pathologic stages for aa women between the two periods , significant differences were observed as far as the increased use of chemotherapy , adjuvant and radiation therapy in this population . based on that , our data suggests that improved survival in aas is likely related to the use of these therapies , as opposed to early detection . as significant difference for pathology stages was observed in caucasian females , survival improvement appears to be related to early detection in addition to adjuvant therapies . burton et al . reported that survival improvements were not related to mammographic screening efforts and concluded that adjuvant therapies must be responsible for survival benefits . adjuvant hormonal and chemotherapeutic administration has increased in australia since 1986 , whereas mammographic rates have remained unchanged . a report studying 5 neighboring european countries with different levels of screening but similar access to treatment revealed that the contrast between the time differences in implementation of mammography screening and the similarity in reductions in mortality between the country pairs suggest that screening did not play a direct part in the reductions in breast cancer mortality . as an exploratory analysis to compare two ethnic groups over two time periods in survival in postoperative patients , we also investigated whether racial disparity affects outcomes . although several authors state that biological factors , access to medical facility , and social economic status contribute to racial disparity [ 3739 ] , other investigations report that racial disparity does not play a major role in outcomes . our data also shows an age - specific disparity in the 40-to 59-year - old females , despite to absence of significant difference of the baseline characteristics of aa and caucasian females in this age ground , suggesting that there exists other factors that contribute to this disparity . a study from natarajan and colleagues analyze breast cancer survival by race , 2,296 black and 24,265 white from 565 hospitals in a long - term survival . race remained a prognostic factor after adjusting for stage , age , and tumor characteristics , which mean survival differences are only partially explained by differences in stages and related factors . newman et al . identified 20 studies from 1980 to 2005 . after adjusting for age , stage , and socioeconomic status , they reported that african american ethnicity was associated with a statistically significant increased mortality risk in overall survival ( mortality hazard , 1.27 ; 95% ci , 1.18 to 1.38 ) and in breast - cancer - specific survival ( mortality hazard , 1.19 ; 95% ci , 1.10 to 1.29 ) . whitman et al . calculated age - adjusted breast cancer mortality rates for women in chicago , new york city , and the usa from 1980 to 2005 . the rate ratios were approximately equal in 1980 and stayed that way until the early 1990s , when the rates started to decline while the aa rates remained rather constant . our study demonstrated age - related racial disparity and the differences were most pronounced in period a , which is in agreement with deshpande et al . . these investigators conducted a retrospective , population - based cohort study seer data from 1988 to 2003 . they compared overall and stage - specific breast - cancer mortality between black and white women within each age ( < 40 , 4049 , 5064 , and 65 + ) and stage ( stage 0-iv and unstaged ) group at diagnosis . racial disparities in breast - cancer - specific mortality were predominantly observed within each stage at diagnosis among women < 65 years old . as we could not find any biological difference between these two groups to explain what we have observed , some other possibilities need to be considered . one limitation of our study is the lack of enough information for the comorbidities such as obesity which may has the potential to impact racial disparity outcomes . one phenomenon that can not be ignored is the rapid increase of the obesity in the usa . the national healthcare quality report from us department of health and human services office of minority health states that african american women have the highest rates of being overweight or obese compared to other groups in the usa . of them , middle - aged adults are more likely to be obese than americans of other ages or ethnic groups . more investigations are reporting that obesity is an independent risk factor for the development of breast cancer , and it has been associated with a poor outcome [ 45 , 46 ] . furthermore , obesity is an independent prognostic factor for developing distant metastases and the effects of adjuvant therapy seem to be lost more rapidly in patients with obesity . most studies report that obesity is correlated with breast cancer in postmenopausal women ; however , study from population - based sample of 1,360 australian women with breast cancer indicated that obesity is independently associated with poorer outcomes in premenopausal women , as it is in postmenopausal women . therefore , we could not exclude the possibility that obesity and/or other comorbidities such as diabetes may attribute to this racial disparity in outcome in our study . several studies have observed adipocytes in close proximity to invasive cancer cells and have been referred to as cancer - associated adipocytes ( caas ) . these cells are considered to be essential for breast tumor development / progression through molecular crosstalk with their invasive cancer cell counterparts . obesity - related effects on insulin levels and the insulin - like growth factor-1 ( igf-1 ) axis , some adipokines , and inflammatory cytokines also stimulate breast cancer growth and metastasis , both directly and most probably by enhanced angiogenesis . exposure to estrogen is an important determinant of the risk of breast cancer , as it stimulates the growth of tissue and its metabolites have been found to be genotoxic and mutagenic . an interesting study shows that body fat distribution may be a better marker of a hormonal pattern associated with increased breast cancer risk than obesity ; obese premenopausal african american ( aa ) women with upper body fat ( ubf ) phenotype have a high - risk hormonal profile [ 52 , 53 ] . moreover , study also found that higher bmi was associated with worse pathologic complete response ( pcr ) . more and more studies are trying to identify predictive factors at the molecular level which is very promising . genomic analyses have subclassified breast cancer into 4 categories : luminal a ( er+ and/or pr+ , her2- ) ; luminal b ( er+ and/or pr+ , her2 + ) ; her2 + ( er- , pr- ) ; and basal - like ( er- , pr- , her2- ) . established molecular biomarkers such as estrogen receptor and progesterone receptor have played a significant role in the hormone treatment . premenopausal aa has a higher likelihood of developing triple negative cancer and has poorer prognoses [ 55 , 56 ] . triple negative breast cancers are increased in aa females regardless of age or body mass index . although our data indicate that the percentage of er+ and pr+ have increased over the two time periods which may account for the better prognosis in period b , we did not have data on her2 status and therefore can not comment on whether or not her2 status affected our survival data . an interesting new theory proposed by demicheli et al . in his review in which he summarized and described that breast cancer may be a mixture of at least 2 main diseases and/or cause pathways-2-diseases assumption [ 59 , 60 ] . the first one is early onset with peak incidence near age 50 years , overrepresented among aa women compared with caucasia women and generally more aggressive outcome . the second breast cancer is late onset with peak incidence at age of 70 years , more indolent course . this theory may be one of the possible explanations of the racial disparity in outcome in this age group as observed in our study . as an exploratory analysis that focuses on subjects who received surgical procedure based on registry data , first , this is a retrospective study and , therefore , is subject to all the biases inherent to a retrospective design . second , is the partially available information for er and pr status that limited sample size and subsequently reduced the power of the study . we observed a fair amount of undermined histological grade and unstaged pathology in our dataset . third , when we divided into age subgroup , the sample sized decreased in the caucasian female group . in general , we can not exclude the possibility of sample bias particularly in caucasian group as the sample size is smaller than the aa group . in conclusion , our study suggests that survival rate significantly improved over the two time periods in both aa and caucasian females . in aas , the improvement is related to adjuvant and radiation treatments , whereas early screening appeared to have a greater affect on caucasians . subgroup analysis indicated that aa survival was decreased in women between the ages of 45 and 60 compared to caucasian females . although registry studies have limitations , they do provide valuable information regarding the multifactorial differences in breast cancer outcomes among african americans as compared to caucasian females . aa women should emphasize prompt initiation of aggressive and specific chemo , adjuvant regimens once diagnosed . early detection of lower - stage tumors will also potentially reduce breast mortality in aa . more future studies identifying differences in gene expressions will help to target and enhance treatment more specifically , such as 21-gene recurrence score . genetic reclassification of histologic grade which delineates new clinical subtypes of breast cancer should be considered to implant in clinical practice for better prediction . a better understanding of the breast cancer at molecular level may lead to interventions that reduce racial disparities in breast cancer survival . Output:	breast cancer survival has significantly improved over the past two decades . however , the diagnosis of breast cancer is lower and the mortality rate remains higher , in african american women ( aa ) compared to caucasian - american women . the purpose of this investigation is to analyze postoperative events that may affect breast cancer survival . this is a retrospective analysis of prospectively collected data from the brooklyn hospital center cancer registry from 1997 to 2010 . of the 1538 patients in the registry , 1226 are aa and 269 are caucasian . the study was divided into two time periods , 19972004 ( period a ) and 20052010 ( period b ) , in order to assess the effect of treatment outcomes on survival . during period a , 5-year survival probabilities of 75.37% , 74.53% , and 78.70% were seen among all patients , aa women and caucasian women , respectively . these probabilities increased to 87.62% , 87.15% and 89.99% in period b. improved survival in aa women may be attributed to the use of adjuvant chemotherapy , radiation , and hormonal therapy . improved survival in caucasian patients was attributed to the use of radiation therapy , as well as earlier detection resulting in more favorable tumor grades and pathological stages .
PubmedSumm118829	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: cancer is one of the most common causes of mortality and morbidity today , with more than 10 million new cases and more than 6 million deaths each year worldwide . it is projected that by 2020 there will be every year 15 million new cases and 10 million cancer deaths . it is estimated that around 43% of cancer deaths are due to tobacco use , unhealthy diets , alcohol consumption and infections . india accounts for 86% of the world 's oral cancer cases , says the study conducted by the national institute of public health in february 2011 . ninety percent of these cases are due to chewing tobacco , unlike in the west where smoking is the main reason . . many properties of mammalian cells are expressed at , or mediated through the cell surface . immense increase in knowledge of altered characteristic of malignant cells glycoproteins are usually defined as protein - carbohydrate complexes in which oligosaccharides and or polysaccharides are joined by covalent linkage to specific amino acids of proteins . the carbohydrate portion contains amino sugars ( glucosamine , galactosamine and sialic acid ) and hexoses ( galactose , mannose ) or fucose . these glycoconjugates especially the terminal epitopes of glycoproteins are thought to play important role in cell - cell interactions , development of cell adhesion , malignant transformation and metastasis.[68 ] sialic acid is thought to be important in determining surface properties of cells and has been implicated in cellular invasiveness , adhesiveness and immunogenicity . fucosylation of glycoproteins at terminal ends is one of the most important features that mediate several specific biological functions . it has been documented that tumor cells modulate their surface by increasing fucosylation levels to escape recognition , thus contribute to decreased adhesion and uncontrolled tumor growth . high serum glycoconjugates levels have been reported in many cancers including head neck and oral cancers indicating their usefulness in diagnosis and monitoring therapy.[1115 ] oral cancer ( oc ) is preceded in many cases by pre cancerous conditions ( pc ) like osmf and pre cancerous lesions ( pl ) like leukoplakia . the malignant transformation rate of osmf is found to be 7.6% and for leukoplakia it is 1 to 17% with highest transformation rate for the lesions on floor of the mouth , soft palate and tongue . in search for biological markers , which can detect changes in oral tissue even at asymptomatic stage would be beneficial to monitor patients with high risk of malignancy , we investigated the serum levels of these glycoconjugates in pc , pl and oc to emphasize their diagnostic role in these diseases . this study was approved by institutional ethical committee , and written consent was taken from every participant . group - i : 40 age and sex matched healthy individuals who are non tobacco and areca quid consumers ( non tobacco control ) . group - ii : 40 age and sex matched healthy individuals who are tobacco and areca quid consumers ( tobacco control ) , who were not suffering from any systemic illness . group - iii comprises 27 newly diagnosed both male and f emale oral leukoplakia patients , group - iv : 27 osmf patients and group - v : 26 oral cancer patients of age between 23 to 50 years who have not received any previous treatment , and or on any antioxidant therapy and were conformed after the detailed case history and histopathological confirmation . blood samples were collected from all the subjects and centrifuged at 4c , serum was stored at -20c for quantitative estimation of glycoconjugates . briefly serum proteins were precipitated by 95% ethanol , and the pellet obtained from centrifugation was dissolved in 0.2 n naoh . the released fucose was reacted with cystein - hcl reagent , to form yellow colored chromospheres , whose intensity was read at 396 and 430 nm . serum protein bound hexoses were estimated by method adopted by weimer and moshin . in brief serum proteins were precipitated by 95% ethanol and the pellet obtained from centrifugation was dissolved in 0.1 n naoh . the hexoses of dissolved proteins were reacted with orcinol- h2so4 reagent to form red colored chromospheres , whose intensity was read at 540 nm . serum sialic acid was estimated by slight modified method of ayala et al . in brief the protein bound sialic acid was released by treating serum with 5% tca followed by boiling . the released sialic acid obtained by filtration with filter paper was treated with diphenylamine reagent to get pinkish red colored chromospheres , whose intensity was read at 530 nm . student t - test was used to assess statistical significance in serum glycoconjugates between non tobacco control , tobacco control , osmf leukoplakia and oral cancer . p value < 0.05 was considered significant and p value < 0.001 were considered as highly significant . one - way analysis of variance ( anova ) was applied to study the statistical significance of the difference in the mean values of above said parameters in precancerous conditions , lesions and oral cancer patients . briefly serum proteins were precipitated by 95% ethanol , and the pellet obtained from centrifugation was dissolved in 0.2 n naoh . the released fucose was reacted with cystein - hcl reagent , to form yellow colored chromospheres , whose intensity was read at 396 and 430 nm . serum protein bound hexoses were estimated by method adopted by weimer and moshin . in brief serum proteins were precipitated by 95% ethanol and the pellet obtained from centrifugation was dissolved in 0.1 n naoh . the hexoses of dissolved proteins were reacted with orcinol- h2so4 reagent to form red colored chromospheres , whose intensity was read at 540 nm . serum sialic acid was estimated by slight modified method of ayala et al . in brief the protein bound sialic acid was released by treating serum with 5% tca followed by boiling . the released sialic acid obtained by filtration with filter paper was treated with diphenylamine reagent to get pinkish red colored chromospheres , whose intensity was read at 530 nm . briefly serum proteins were precipitated by 95% ethanol , and the pellet obtained from centrifugation was dissolved in 0.2 n naoh . the released fucose was reacted with cystein - hcl reagent , to form yellow colored chromospheres , whose intensity was read at 396 and 430 nm . serum protein bound hexoses were estimated by method adopted by weimer and moshin . in brief serum proteins were precipitated by 95% ethanol and the pellet obtained from centrifugation was dissolved in 0.1 n naoh . the hexoses of dissolved proteins were reacted with orcinol- h2so4 reagent to form red colored chromospheres , whose intensity was read at 540 nm . serum sialic acid was estimated by slight modified method of ayala et al . in brief the protein bound sialic acid was released by treating serum with 5% tca followed by boiling . the released sialic acid obtained by filtration with filter paper was treated with diphenylamine reagent to get pinkish red colored chromospheres , whose intensity was read at 530 nm . student t - test was used to assess statistical significance in serum glycoconjugates between non tobacco control , tobacco control , osmf leukoplakia and oral cancer . p value < 0.05 was considered significant and p value < 0.001 were considered as highly significant . one - way analysis of variance ( anova ) was applied to study the statistical significance of the difference in the mean values of above said parameters in precancerous conditions , lesions and oral cancer patients . table 1 shows the levels of serum glycoconjugates in all the five groups and we observed statistically highly significant levels in osmf , leukoplakia and oc when compared with control ( p < 0.001 ) and shows no statistical difference in these serum glycoconjugates levels between non tobacco control and tobacco control ( p > 0.05 ) . table 2 shows the mean difference in serum levels of above said glycoconjugates between osmf , leukoplakia and oc and we observed significant difference in them ( p < 0.001 ) . the serum glycoconjugates levels in non tobacco control , tobacco consuming control , osmf , leukoplakia and oral cancer one - way anova of serum glycoconjugates levels between osmf , leukoplakia and oral cancer alterations in the cell surface glycosylation during transformation of a normal cell to a malignant cell have been suggested for many years . measurements of protein bound carbohydrates have been used as an index to glycoprotein levels that may be valuable in establishing diagnosis , staging of disease , detecting metastasis , identifying patients at high risk for recurrence and evaluating therapeutic response . many researchers[2225 ] observed increased serum glycoproteins like fucose , sialic acid in different types of malignancies like melanoma , breast cancer , and carcinoma of cervix and brain tumor . the carbohydrate moiety of these glycoproteins can be released into circulation through increased turnover , secretion and or shedding and are considerable interest for their potential diagnostic and prognostic value . in our study we observed no significant difference in serum glycoconjugates levels between non tobacco control and tobacco consuming controls ( p > 0.05 ) , suggesting that the glycoconjugates are directly correlated with the disease activity , and they are not affected by dietary habits . the same was observed by bina et al . in their study indicating no effective role of dietary variation on serum glycoconjugates levels . in this study serum levels of protein bound hexoses were significantly higher in osmf , leukoplakia and oral cancer ( p < 0.01 ) and was positively correlated with studies done by neeraj taneja et al . of the increasing pattern we observed very high levels in oc followed by leukoplakia and the difference in serum protein bound hexoses between osmf and leukoplakia is insignificant ( p > 0.05 ) . in this study we observed a very high serum fucose in osmf , leukoplakia and oc , when compared to controls ( p < 0.001 ) as like that was observed by parwani rn et al.28 in their study . according to manisha shah et al . high fucosylation one of the characteristic feature of malignancies is mainly due to increased activity of fucosyl transferase activity in malignant tissue . at the same time we observed an interesting and significant observation that there was a significant difference in serum fucose levels between osmf and leukoplakia , positively indicating the potential malignant transformation rate of leukoplakia in compare to osmf and effective role of fucosylation and fuco - proteins in malignant transformation of normal cells . sialic acid is a major constituent of carbohydrate moiety of cell membrane glycoproteins and glycolipids . in this study we observed significantly higher serum levels of sialic acid in osmf , leukoplakia and oc ( p < 0.01 ) and were positively correlated with findings of other studies.[3032 ] neoplasms often have increased concentration of sialic acid on tumor cell surface and sialoglycoproteins are shed or secreted by these cells increasing their concentration in blood . this increase in cancer is might also be due to selective increase in existing specific sialylated sequence or a tumor associated de - nova synthesis of specific sialylated sequence . from this study we conclude that serum glycoconjugates like sialic acid , fucose and protein bound hexoses can be used as routine markers in diagnosing oral pre malignant conditions , lesions and malignancies . more over in oral leukoplakia serum fucose can be better diagnostic and or prognostic marker of all the above glycoconjugates . Output:	background : cancer is one of the most common causes of mortality and morbidity today , with more than 10 million new cases and more than 6 million deaths each year worldwide . globally oral cancer is the sixth most common cause of cancer related death . india accounts for 86% of the world 's oral cancer cases . often it proceeds by pre cancerous conditions and lesions . in search for biological markers with diagnostic value , we investigated serum glycoconjugates like protein bound hexoses , fucose and sialic acid in these diseases.materials and methods : for this study 27 newly diagnosed oral leukoplakia , 27 osmf and 26 oral cancer patients , 40 healthy controls who are non tobacco users and 40 healthy controls who are tobacco users were selected . in all these groups we estimated serum glycoconjugates.results:we observed no difference in serum glycoconjugates levels between tobacco and non tobacco controls ( p > 0.05 ) , but very high levels in oral cancer , leukoplakia and oral sub mucous fibrosis ( osmf ) patients ( p < 0.001 ) when compared to control groups . fucose levels were significant ( p < 0.05 ) of all the glycoconjugates between osmf and leukoplakia.conclusion:the serum glycoconjugates whose levels were very high in osmf , leukoplakia and oral cancer , do have a significant diagnostic and prognostic value in these diseases .
PubmedSumm118830	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: during may 8june 15 , 2009 , a total of 273 wild birds died in the wetlands of gengahai lake , qinghai province , china ( figure 1 ) during an influenza outbreak . we obtained 224 great crested grebes ( podiceps cristatus ) , 16 great black - headed gulls ( larus ichthyaetus ) , 15 brown - headed gulls ( larus brunnicephalus ) , 9 bar - headed geese ( anser indicus ) , 5 ruddy shelducks ( tadorna ferruginea ) , 3 great cormorants ( phalacrocorax carbo ) , and 1 common coot ( family rallidae ) ( figure 1 ) . location in qinghai , china , of dead birds that were tested for avian influenza virus ( h5n1 ) , with images and common names of bird species tested . red box indicates gengahai lake , where dead birds were detected , and green box indicates bird islet of qinghai lake ; the distance between them is 90 km . numbers of dead birds of each species are indicated in parentheses . to determine the pathogenesis of this outbreak , we obtained organs , including lung and brain , and cloacal swabs from 13 birds at different times . eleven avian influenza viruses ( h5n1 ) were isolated from 3 species of wild birds : 4 from great crested grebes , 5 from great black - headed gulls , and 2 from brown - headed gulls . results of virus isolation for samples from a bar - headed goose and a shelduck were negative . we sequenced genomes of the 11 viruses and found that the viruses ( qh09 ) were closely related and showed 100% homology at the nucleotide level . sequences of the entire genome of qh09 ( representative strain a / great crested grebe / qinghai/1/09 ) are available in genbank ( accession nos . hemagglutinin of qh09 virus had a series of basic amino acids ( pqrerrrkr ) at the cleavage site . neuraminidase of this virus had a deletion of 20 aa at residues 4968 in the stalk region . no amino acid substitutions conferred resistance to adamantane or neuraminidase inhibitors . unlike many isolates related to qinghai lake strains of clade 2.2 , qh09 virus does not have an e627k substitution in basic polymerase . nonstructural protein 1 had a deletion of 5 aa at residues 8084 , which is commonly observed in hpai viruses ( h5n1 ) that are circulating in southeast asia . seven gene segments of qh09 , except for the acidic polymerase ( pa ) gene , showed the greatest homology with 2 clade 2.3.2 viruses , a / little egret / hongkong/8863/07(h5n1 ) and a / whooper swan / hokkaido/1/08(h5n1 ) ; identities were 97.0%99.5% . the strain that showed the greatest homology with qh09 pa was a / chicken / yamaguchi/7/04 ( h5n1 ) , which was the precursor of the pa gene of the a / bar - headed goose / qinghai/2/05 virus ( 1 ) ( table ) . homology of the 8 gene segments of qh09 with qh05-like viruses was 92%96.3% . * ha , hemagglutinin ; na , neuramindase ; pb , basic polymerase ; pa , acidic polymerase ; np , nucleoprotein ; m , matrix ; ns , nonstructural . phylogenetic analysis showed that 7 of 8 gene fragments of qh09 , except for the pa gene , mapped with clade 2.3.2 viruses a / little egret / hongkong/8863/07 and a / whooper swan / hokkaido/1/08 and were in a different cluster than clade 2.2 viruses isolated in qinghai during 20052007 ( figure 2 , panel a ) . the pa gene of qh09 had the same lineage as a / chicken / yamaguchi/7/04 ( figure 2 , panel b ) . phylogenetic trees of hemagglutinin genes ( nt 291,728 ) ( a ) and acidic polymerase genes ( nt 252,151 ) of avian influenza viruses ( h5n1 ) ( b ) . clade numbers are indicated on the right in panel a. trees were constructed by using the phylip program of clustalx software version 1.81 ( www.clustal.org ) , the neighbor - joining algorithm , and rooted to a / chicken / pennsylvania/1/83(h5n2 ) . viruses obtained in this study are shown in red , previously detected viruses that are closely related to avian influenza virus ( h5n1 ) qh09 are shown in blue , and closely related viruses that were detected after the qinghai wild bird outbreak in 2009 are shown in green . gcg , great crested grebe ; gbh , great black - headed gull ; bh , brown - headed gull ; gb , grebe ; ws , whooper swan ; cm , common magpie ; bg , bean goose ; rs , ruddy shelduck ; bhg , bar - headed goose ; le , little egret ; pk , pike ; dk , duck ; md , muscovy duck ; tk , turkey ; ck , chicken ; gs , goose ; cg , common goldendye . antigenic analyses by hemagglutination inhibition ( hi ) assay with chicken antiserum against a qh05 virus ( a / bar - headed goose / qinghai/3/05 ) ( clade 2.2 ) and qh09 virus showed that the cross - reactive hi titer of qh09 virus ( 64 ) was 16-fold lower than that of homologous qh05 virus ( 1,024 ) . the cross - reactive hi titer of qh05 virus ( 128 ) was also 16-fold lower than that of homologous qh09 virus ( 2,048 ) . genetic and antigenic characterization of hpai viruses ( h5n1 ) from wild birds in qinghai in 2009 suggests that these viruses are closely related to clade 2.3.2 and are clearly distinguishable from the classical qh05 clade 2.2 . previously reported qh05-like virus represented > 4 genotypes , and no 2 qh05-like viruses were identical at the amino acid or nucleotide sequence levels ( 1,6 ) . although isolates of qh09 were obtained from 3 species at different times , 100% homology of the 11 isolates of qh09 was observed , which suggests that wild birds in qinghai in 2009 were newly infected by 1 strain of virus . clade 2.3.2 viruses from wild nonpasserine bird species were reported in hong kong in 20072008 ( 10 ) . the fact that a similar virus was isolated from a whooper swan ( order anseriformes ) in japan in 2008 showed that clade 2.3.2 was dispersed by migration of wild birds ( 11 ) . our results indicated that qh09 virus is a reassortant containing 7 gene segments of clade 2.3.2 viruses detected in wild birds and the pa gene of ck / yamaguchi/7/04-like virus , which contributed the pa gene to 1 qh05 virus ( 1 ) . similar genotypes of qh09-like clade 2.3.2 viruses were also detected in great - crested grebes and black - headed gulls in russia in 2009 ( 12 ) . bar - headed geese , whooper swans , and other anseriforme birds in mongolia were infected with qh09-like clade 2.3.2 viruses ( 13 ) . therefore , qh09-like clade 2.3.2 virus is likely adapted to wild birds and is similar to clade 2.2 viruses , and its presence in qinghai suggests that wild birds have spread this virus to other regions . the possibility that wild birds in qinghai in 2009 were infected by domestic fowl that harbored clade 2.3.2 virus is low because of the location of qinghai province and the scarcity of poultry in this region . in addition , no influenza outbreak in poultry occurred in this region in 2009 . the ecology , epidemiology , genetics , and evolution of this virus are not fully understood . qh05-like clade 2.2 viruses and clade 2.3.2 viruses have been detected in wild pikas ( 14 ) . however , whether the 2 virus clades have propagated in other mammalian hosts is unknown . although there are no reports of detection of clade 2.3.2 virus in wild birds near qinghai lake , the finding of clade 2.3.2 virus in the gengahai wetlands of qinghai increases concerns about a potential pandemic and the likelihood that avian influenza virus ( h5n1 ) will again spread and increase its genetic diversity . therefore , determining movements of wild migratory waterfowl from qinghai lake and their virologic status is needed to assess potential avian vectors of hpai virus ( h5n1 ) . Output:	highly pathogenic avian influenza virus ( h5n1 ) ( qh09 ) was isolated from dead wild birds ( 3 species ) in qinghai , china , during may june 2009 . phylogenetic and antigenic analyses showed that qh09 was clearly distinguishable from classical clade 2.2 viruses and belonged to clade 2.3.2 .
PubmedSumm118831	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: thiamine ( vitamin b1 ) is a water - soluble vitamin absorbed in the duodenum and jejunum that functions as a coenzyme essential for glucose metabolism and neuronal activity.123 thiamine deficiency can result in wernicke 's encephalopathy ( we ) , which is a serious neurologic disorder and characterized by the clinical triad of acute mental confusion , ataxia , and ophthalmoplegia.4 in developed countries , thiamine deficiency is typically associated with chronic alcoholism because alcohol affects thiamine uptake and utilization.4 however , we may develop in non - alcoholic conditions such as prolonged starvation , gastrointestinal disease , vomiting due to hyperemesis gravidarum , and increased nutrient requirements such as in cases of trauma or septic shock.24 because we can be frequently undiagnosed and easily confused with other neurological problems , it may be more prevalent than commonly estimated . recently , the prevalence of we in intravenously fed patients owing to a lack of thiamine supplementation has been increasing.3 the indications for total parenteral nutrition ( tpn ) are inadequate nutrient absorption resulting from short bowel syndrome , gastrointestinal fistula , bowel obstruction , and prolonged bowel rest . these conditions are frequently met in patients with cd.5 here , we report the two cases of severely malnourished young patients with cd who developed we after prolonged tpn . a 22-year - old male patient diagnosed with cd was referred to our emergency room because of massive hematochezia and hypovolemic shock . he was treated for active cd involving the ileum and colon with a penetrating phenotype during a previous admission period . ct performed at another hospital revealed that the cd also involved multiple segments of the small bowel , including the jejunum , which is the main site of thiamine absorption ( fig . initially , he was severely malnourished , with a bmi of 17.8 kg / m . initial laboratory findings were as follows : white blood cell ( wbc ) count 22,850/l ; hemoglobin level 8.8 g / dl ; platelets 157,000/l , crp level 0.03 mg / dl ; protein level 3.0 g / dl ; albumin level 1.8 g / dl ; triglyceride level 73 mg / dl ; cholesterol level 119 mg / dl ; bun level 6 mg / dl ; creatinine level 1.09 mg / d ; and prothrombin time / international normalized ratio 20.6 s ( 1.78 ) . emergent angiography revealed active bleeding from the ileal branch of the superior mesenteric artery , and the interventionist performed embolization using glue and lipiodol . in addition , abdominal ct suspected right - sided perianal abscess . he underwent incision and drainage with primary closure for the perianal abscess . after surgical intervention , the fasting period was continued for about 3 weeks , and peripheral tpn ( combiflex lipid peri 1920 ml ) without thiamine supplementation was administered during the fasting period . he started to consume a liquid diet , and 2 days later complained of progressive blurred vision , cognitive dysfunction , intermittent confused speech , and dizziness . he also experienced a brief course of generalized tonic - clonic seizure for 10 minutes . neurologic examination and electroencephalography were not able to identify any abnormal neurologic signs except for slight latent nystagmus in the lateral gaze . mri revealed a high signal - intensity lesion at the both right and left sides of the mammillary body and tectum , and the periaqueductal space on a t2-weighted image ( t2wi , fig . he was discharged without any neurologic sequelae , and an oral vitamin supplement was prescribed . a 34-year - old female patient who was diagnosed with cd involving the small bowel including the distal ileum complained of abdominal cramping pain , postprandial vomiting , and diarrhea . her symptoms were aggravated despite treatment with an anti - tumor necrosis factor - alpha agent . initial laboratory findings were as follows : wbc count 22,850/l ; hemoglobin level 8.8 g / dl ; platelet count 423,000/l ; crp level 0.03 mg/ dl ; protein level 3.0 g / dl ; albumin level 1.8 g / dl ; cholesterol level 182 mg / dl ; bun level 6 mg / dl ; creatinine level 1.09 mg / dl ; and prothrombin time / international normalized ratio 13.1 s ( 1.27 ) . an abdominal ct scan revealed enteromesenteric fistula , enteroenteric fistula , and intraabdominal abscess ( fig . 3 ) , which were treated by fasting , high dose steroids , and antibiotics . she was also treated with peripheral tpn ( combiflex lipid peri 1920 ml ) without thiamine supplementation . after 17 days of fasting , she complained of sudden - onset dizziness and gait ataxia . the next day , her symptoms worsened and new symptoms including nausea , vomiting , and blurred vision developed . there was no organic abnormality apparent to explain her symptoms in ophthalmologic and otolaryngological examinations . brain mri revealed a high signalintensity lesion at the inferior colliculus of the midbrain and pontomedullary junction on a ( fig . although she underwent ileocecectomy for fistula and intraabdominal abscess , her neurologic symptoms were fully resolved . a 22-year - old male patient diagnosed with cd was referred to our emergency room because of massive hematochezia and hypovolemic shock . he was treated for active cd involving the ileum and colon with a penetrating phenotype during a previous admission period . ct performed at another hospital revealed that the cd also involved multiple segments of the small bowel , including the jejunum , which is the main site of thiamine absorption ( fig . initially , he was severely malnourished , with a bmi of 17.8 kg / m . initial laboratory findings were as follows : white blood cell ( wbc ) count 22,850/l ; hemoglobin level 8.8 g / dl ; platelets 157,000/l , crp level 0.03 mg / dl ; protein level 3.0 g / dl ; albumin level 1.8 g / dl ; triglyceride level 73 mg / dl ; cholesterol level 119 mg / dl ; bun level 6 mg / dl ; creatinine level 1.09 mg / d ; and prothrombin time / international normalized ratio 20.6 s ( 1.78 ) . emergent angiography revealed active bleeding from the ileal branch of the superior mesenteric artery , and the interventionist performed embolization using glue and lipiodol . in addition , abdominal ct suspected right - sided perianal abscess . he underwent incision and drainage with primary closure for the perianal abscess . after surgical intervention , the fasting period was continued for about 3 weeks , and peripheral tpn ( combiflex lipid peri 1920 ml ) without thiamine supplementation was administered during the fasting period . he started to consume a liquid diet , and 2 days later complained of progressive blurred vision , cognitive dysfunction , intermittent confused speech , and dizziness . he also experienced a brief course of generalized tonic - clonic seizure for 10 minutes . neurologic examination and electroencephalography were not able to identify any abnormal neurologic signs except for slight latent nystagmus in the lateral gaze . mri revealed a high signal - intensity lesion at the both right and left sides of the mammillary body and tectum , and the periaqueductal space on a t2-weighted image ( t2wi , fig . he was discharged without any neurologic sequelae , and an oral vitamin supplement was prescribed . a 34-year - old female patient who was diagnosed with cd involving the small bowel including the distal ileum complained of abdominal cramping pain , postprandial vomiting , and diarrhea . her symptoms were aggravated despite treatment with an anti - tumor necrosis factor - alpha agent . initial laboratory findings were as follows : wbc count 22,850/l ; hemoglobin level 8.8 g / dl ; platelet count 423,000/l ; crp level 0.03 mg/ dl ; protein level 3.0 g / dl ; albumin level 1.8 g / dl ; cholesterol level 182 mg / dl ; bun level 6 mg / dl ; creatinine level 1.09 mg / dl ; and prothrombin time / international normalized ratio 13.1 s ( 1.27 ) . an abdominal ct scan revealed enteromesenteric fistula , enteroenteric fistula , and intraabdominal abscess ( fig . 3 ) , which were treated by fasting , high dose steroids , and antibiotics . she was also treated with peripheral tpn ( combiflex lipid peri 1920 ml ) without thiamine supplementation . after 17 days of fasting , she complained of sudden - onset dizziness and gait ataxia . the next day , her symptoms worsened and new symptoms including nausea , vomiting , and blurred vision developed . there was no organic abnormality apparent to explain her symptoms in ophthalmologic and otolaryngological examinations . brain mri revealed a high signalintensity lesion at the inferior colliculus of the midbrain and pontomedullary junction on a ( fig . although she underwent ileocecectomy for fistula and intraabdominal abscess , her neurologic symptoms were fully resolved . micronutrient deficiencies in cd patients are not uncommon and usually result in a combination of reduced dietary intake , disease - related malabsorption , and a catabolic state.16 decreased serum thiamine levels are often reported in patients with cd.7 thiamine is an essential vitamin for glucose metabolism and energy production , and requirements increase during critical illness and chronically depleted states.4 the active form of thiamine ( thiamine pyrophosphate ) is also a cofactor in several biochemical pathways in the brain.8 because thiamine - dependent enzymes play an important role in cerebral energy use , deficiencies may initiate tissue injury by inhibiting metabolism in brain regions with high metabolic requirements and high thiamine turnover.9 we is a significantly disabling and potentially lethal condition that can be caused by thiamine deficiency and fully reversed with early thiamine replacement . previously , only five cases of cd with we have been reported in the literature . one was in a patient with clinically inactive cd,10 the second was in a young patient receiving tpn without vitamin supplementation,11 the third was in a middle - aged woman who suffered from chronic diarrhea and vomiting,12 the fourth was in patient receiving tpn during the postoperative period,1 and the last was in a korean patient who was diagnosed with cd and an enterocutaneous fistula . this final patient was also supported by prolonged tpn.5 the patient in the current report had several risk factors for thiamine deficiency , such as an underlying malnourished state , active cd combined with infection , and postoperative state . despite the relatively short period of fasting , the active inflammation caused by active cd , underlying malnourished state , infection , and surgery led to an increased thiamine requirement and the development of we . in addition , refeeding syndrome , which is a life threatening shift of electrolyte and fluid levels caused by initial refeeding in malnourished patients , could be a co - existing factor . we frequently occurs during early oral feeding periods.13 in the presence of excess glucose , low levels of thiamine could also potentially cause non - alcoholic we . we is diagnosed clinically and has no characteristic and pathognomonic abnormalities in diagnostic studies . the only clinical clue for we is the symptom triad including ophthalmopathy , cerebellar dysfunction , and confusion.348 laboratory and radiographic tests remain important to exclude alternate or coexisting medical conditions . an assay for serum thiamine is not typically available for timely diagnostic purposes , and its sensitivity , specificity , accuracy , and doseresponse relationship have not yet been proven.9 however , thiamine levels may help clinicians to differentiate in ambiguous cases . thiamine is a cofactor of several enzymes involved in glucose metabolism and cerebral energy utilization , so its depletion results in neuronal damage which can be seen on mri , including t2 and fluidattenuated inversion recovery hyper - intense signaling in the mammillary bodies , periventricular thalamus , and periaqueductal gray matter , as well as diffusion - weighted imaging to differentiate vasogenic from cytotoxic edema.141516 if patients present with symptoms consistent with we , they should be empirically treated with a high dose of thiamine hydrochloride.8 however , there is no consensus on the optimal dose of thiamine , duration of treatment , or number of treatments . according to many case reports , treatment with either 100 or 200 mg of intravenous thiamine is curative in non - alcoholics . however , alcoholic patients with we may need higher daily doses , and 500 mg three times daily has been recommended . the administration of thiamine alleviates the symptoms of we to some degree in almost all cases . however , persistent neurologic dysfunction is common . opthalmoplegia and mental confusion are typically resolved , but nystagmus and gait ataxia usually remain.9 it is important to remember that the early diagnosis and treatment of we is crucial in order to avoid persistent brain damage.8 the development of acute encephalopathy in patients with malnutrition and inflammation should always raise the suspicion of thiamine deficiency . if in doubt , treatment should be followed , as the administration of thiamine is not potentially harmful . it should be emphasized that thiamine supplementation is crucial in all patients with a compromised gut . the present case demonstrates to gastroenterologists that severe nutritional deficiencies such as those related to we can develop acutely in malnourished cd patients within relatively short periods of fasting . Output:	micronutrient deficiencies in crohn 's disease ( cd ) patients are not uncommon and usually result in a combination of reduced dietary intake , disease - related malabsorption , and a catabolic state . decreased serum thiamine levels are often reported in patients with cd . wernicke 's encephalopathy ( we ) is a severe form of thiamine deficiency that can cause serious neurologic complications . although we is known to occur frequently in alcoholics , a number of non - alcoholic causes have also been reported . here , we report two cases of non - alcoholic we that developed in two severely malnourished cd patients who were supported by prolonged total parenteral nutrition without thiamine supplementation . these patients complained of sudden - onset ophthalmopathy , cerebellar dysfunction , and confusion . magnetic resonance imaging allowed definitive diagnosis for we despite poor sensitivity . the intravenous administration of thiamine alleviated the symptoms of we dramatically . we emphasize the importance of thiamine supplementation for malnourished patients even if they are not alcoholics , especially in those with cd .
PubmedSumm118832	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: from 19962011 , the total fertility rate in nepal decreased from 4.6 to 2.6 births per woman . during the same time , the contraceptive prevalence rate was 50% among married women and 38% among all women.1,2 family planning services in nepal are provided by government - run health care facilities as well as by nongovernmental organizations , private facilities , and pharmacies.1,3 contraceptive methods are financially supported by the government , and in 2006 about 70% of women obtained their contraceptives free of charge.4 according to a national health survey , almost all nepalese women of fertile age ( 99% ) , including women seeking abortion , know about at least one modern contraceptive method.1,5 the most well - known methods include female and male sterilization , condoms , depo - provera ( intramuscular progestin injection ) and combined oral contraceptives . knowledge of long - acting reversible methods has been reported by a high percentage ( 83% for intrauterine copper devices and 90% for subcutaneous progestin implants ) , whereas only 29% have heard of emergency contraception ( progestin - only emergency contraceptive pills ) . despite the good knowledge about modern contraceptive methods , more than every fourth married woman is considered to have an unmet need for contraception.1 more than 50% of nepalese women stop using their birth control method within 12 months of starting , most often due to the experience of side effects , eg , poor bleeding control.1,4,68 however , women who received high levels of information about the contraceptives and their side effects were more likely to continue using them.6 induced abortion was legalized in nepal in 2002 , and the first comprehensive abortion care service was started in kathmandu in 2004 . still , 2 years later , only 50% of comprehensive abortion care clients seeking an abortion were aware that abortion was legal in nepal.9 there are both government - run services and private clinics . according to a national facility - based abortion study by the government of nepal , almost all clients were married , had at least primary education , and had at least one living child.9 common reasons for terminating the pregnancy were economic problems and that the family was considered completed and there was no desire for additional children . the majority of the comprehensive abortion care clients had used a birth control method , most commonly a condom , before the pregnancy . almost all clients received post - abortion contraceptive counseling , the most commonly accepted method being depo - provera.9 khanal et al studied practices and perceptions on contraception in a small sample of nepalese women seeking abortion.5 they concluded that the knowledge of available methods was generally good , whereas the knowledge and acceptance of side effects was poor , leading to discontinuation and risk of unwanted pregnancies . repeated abortions are emerging as a major public health issue in nepal , where every third abortion is a repeat abortion.10 in a study by thapa et al , almost every fifth woman undergoing her first abortion did not have any contraceptive method dispensed by the time of discharge , which of course contributes to the risk of repeated abortions.11 a better understanding of the women s knowledge of and attitudes toward contraception is crucial in the efforts to avoid unwanted pregnancies . the aim of this study was to map the knowledge of and attitudes toward contraceptives among a sample of women aged 1549 years seeking medical care in kathmandu , nepal . the primary question was if the knowledge of and attitudes toward contraceptives differed between women seeking induced abortion and women of the same age seeking other medical care at kathmandu medical college teaching hospital ( kmc ; kathmandu , nepal ) . the hypothesis was that women seeking induced abortion have a poorer knowledge of contraceptive methods compared to women seeking gynecological care for other reasons . women included in the study sought medical care at the outpatient department of gynecology and obstetrics ( opd ) at kmc . they were recruited either at the opd or at the ward when they had been admitted . a case was defined as a woman who sought an elective medical or surgical abortion , or who came to undergo a previously planned elective abortion . a control was defined as a woman who sought medical care at the opd or had already been admitted to the ward for reasons other than elective abortion . the exclusion criteria were known infertility , including previous sterilization , and serious illness that impaired the subject s ability to answer questions . parts of three previously validated questionnaires were used to construct a suitable questionnaire in english for the study.1214 the questions dealt with demographic characteristics and contraceptive knowledge . thus , questions were asked about which contraceptives and birth control methods the woman knew of , and at what stage in the fertilization process different contraceptives work . questions were also asked about how effective different methods were believed to be and if the methods were assumed to affect the ability to become pregnant after terminating its use . the women got one point per correct answer about the efficiency of five different contraceptives . to test attitudes toward contraceptives , questions were asked about how important they considered different features of birth control methods to be . when collection of data had started in kathmandu , 17 questions were excluded because of too scant knowledge about the fertilization process among the study subjects . the final questionnaire used in the study consisted of 29 questions . data were collected from january to april 2013 by two of the authors ( eb and ms ) . all women seeking an elective abortion during this period were invited to participate in the study . women seeking medical care at kmc for reasons other than unwanted pregnancy were used as controls . the original plan was to invite and include the controls by interviewing the next patient in the opd after a case and the patient in a bed next to a case in the ward . because of practical problems , this was not always possible ; hence , as many controls as possible were collected . to minimize the risk of selection bias , the examiners were not informed by the local staff on why the woman sought medical care . the women were informed orally about the project and gave their informed consent to participate in an interview based on the questionnaire . doctors and nurses helped to conduct the interviews by orally translating the english questionnaire into nepali . the questionnaire was filled out by two of the authors ( eb or ms ) or the doctor / nurse in accordance with the answers given by the woman . the questionnaires were handled confidentially and not coded , and could not afterwards be associated with any individual . the study was approved by the local ethical committee and the head of gynecology and obstetrics at kmc . ibm spss statistics 20.0 ( ibm corporation , armonk , ny , usa ) was used for analysis . student s t - test and analysis of variance were used for analysis of normally distributed parametric data , whereas the mann whitney u - test and kruskal wallis test were used in cases where data were not normally distributed . the mann whitney u - test was used as a post - hoc test for the kruskal pearson s chi - square test and risk ratio was used to compare categorized data . a 95% confidence interval and p0.05 most analyses compared results between cases and controls , but to analyze the knowledge of contraceptives in relation to demographic data , results from both groups were summarized and handled as one group . to analyze correlations between variables , linear regression with pearson s correlation coefficient was used . ibm spss statistics 20.0 ( ibm corporation , armonk , ny , usa ) was used for analysis . student s t - test and analysis of variance were used for analysis of normally distributed parametric data , whereas the mann whitney u - test and kruskal wallis test were used in cases where data were not normally distributed . the mann whitney u - test was used as a post - hoc test for the kruskal pearson s chi - square test and risk ratio was used to compare categorized data . a 95% confidence interval and p0.05 most analyses compared results between cases and controls , but to analyze the knowledge of contraceptives in relation to demographic data , results from both groups were summarized and handled as one group . to analyze correlations between variables , linear regression with pearson s correlation coefficient was used . three women declined , 13 were excluded ( four did not speak nepali , nine due to their state of health ) , and four withdrew after the interview had started . this generated 153 women consisting of a case group of 64 women and a control group of 89 women . there was no significant difference between the two groups regarding age , marital status , or income even though the income varied substantially within each group . almost all women ( 94.8% ) stated they were married ; 88.2% were hindus and 7.8% were buddhists . women seeking an abortion had a significantly higher number of total pregnancies ( mean value 2.7 versus 2.0 ) and live births ( mean value 1.3 versus 0.8 ) compared to the control group ( table 1 ) . eighty - two percent of controls and 71.1% of cases had at least primary education ( nonsignificant ) . women in the control group were more likely to have a high education ( school leaving certificate and above ) than women seeking an abortion at kmc ( p=0.018 ) . in total , 96.1% of the participants knew about at least one modern method of birth control ( 93.8% of cases and 97.8% of controls ) , but traditional methods like withdrawal and breastfeeding were less known ( figure 1 ) . the method best known by the women was depo - provera ( 89.5% ) , followed by condom ( 88.9% ) and oral contraceptives ( 81.7% ) . there was no significant difference between cases and controls in number of methods known , knowledge of the efficiency of different contraceptives , or whether oral contraceptives affect the ability to become pregnant after termination of use . significantly more of the cases than controls considered themselves having received information from their doctor or other health care provider about birth control methods ( 73.4% of cases versus 49.4% of controls ; p=0.003 ) but there was no difference regarding number of contraceptive methods known between the women claiming they had been informed and those who had not . women who had previously given birth or undergone an elective abortion were more than two times more likely to have been informed by their doctor or provider about contraceptives ( 75% versus 36% ; risk ratio 2.56 ; confidence interval 1.713.82 ) . ten percent of controls and 20% of cases claimed they had become pregnant despite using a birth control method . there was no significant difference between the cases and controls concerning whether they had ever used any birth control methods . there was no significant correlation between age and number of birth control methods known or between age and correctly believed efficiency of different contraceptives . neither was there any significant correlation between income and number of birth control methods known or between income and correctly believed efficiency of different contraceptives . women with a high education ( school leaving certificate and above ) on average knew about 6.9 birth control methods compared to 4.7 among women lacking formal education ( p<0.001 ) and 4.2 in women with only primary education ( p<0.001 ) . on the other hand , women with a high education did not have more correct answers than women without formal education about the efficiency of different methods . there was no significant difference between cases and controls regarding how important different features of birth control were considered to be when choosing a birth control method . the three features that had the highest total proportion of women answering that it was important ( above 90% for all three ) were the features : easy to use , easy access , and highest possible effectiveness . the results from this study show that contraceptive knowledge among nepalese women did not differ significantly between women seeking an abortion and a control group . the general knowledge of contraceptive methods was good , although not as good as has previously been described.5 previous studies indicate that women seeking an abortion have a lower contraceptive knowledge than women intending to give birth.15 the hypothesis that contraceptive knowledge among women seeking abortion would be lower than in a control group of women could not be confirmed . on the contrary , this study shows that women seeking an abortion have received more information about birth control than the women in the control group , but they still do not seem to have better knowledge about contraceptives , including number of methods known , expected efficiency of different contraceptives , and whether oral contraceptives affect the fertility after termination of use . similarly , there was no difference in contraceptive knowledge between women who had received information from their doctor or other health care provider about contraceptives and women who had not received information . these findings together indicate that the information about birth control given by doctors or other health care providers is insufficient and that contraceptive counseling needs to be improved . this is in line with findings from high resource countries , such as sweden , where the rate of repeated abortion exceeds 40% and the contraceptive counseling in relation to the abortion visits most often is clearly insufficient.16 thus , it seems as if the quality of contraceptive information and counseling is more related to attitudes rather than resources . there was no significant difference in attitudes about contraceptive methods between the two groups , which might be explained by the generally poor knowledge regarding the efficiency of different contraceptive methods . regardless course of action , attitudes about birth control should be further investigated to find ways to increase contraceptive use and avoid unwanted pregnancies . it was found that 75% of the women with at least one previous abortion or live birth had been informed about contraceptives by their doctor or provider compared to only 36% of women who had not delivered any children or gone through an abortion . these results support the theory that the major source of information about contraceptives in kathmandu is counseling in relation to childbirth or abortion , as women with these experiences had a 2.5 times greater chance to have been informed about contraceptives compared to women pregnant for the first time . this is in line with the finding that more women in the case group than in the control group had been informed about contraceptives since they had more children than the control group . this also emphasizes the need for contraceptive counseling to women without a history of previous pregnancies . the feature associated with better knowledge about contraceptives was instead higher education , in line with the results of several previous studies.1,8,17 even though there was a higher proportion of women with a high education in the control group , the difference in contraceptive knowledge between the cases and controls was not significant . previous studies conclude other important factors to be income and socioeconomic status.1,8 since this study showed no significant difference in income , this could be a reason why the contraceptive knowledge did not differ between cases and controls . unfortunately , systematic recruitment of controls in the opd was not always possible as the doctors needed for translation were often busy performing more urgent tasks ; thus , the study population could be considered as a convenience sample . although this could mean a risk for bias , most demographic characteristics of participants , such as age , marital status , and income , were similar in the two groups , which decreases the risk of these features affecting the result . the age , marital status , religion , and level of education of the women in this study furthermore correlate well with earlier identified characteristics of women seeking an elective termination of pregnancy in nepal.9 there is always a risk for bias when a questionnaire is translated , especially orally and by several people . even though the questionnaire had been validated beforehand in swedish , the translators could have interpreted the questions differently which could have affected the answers and further the results of the study . not all of the doctors and nurses who translated the interviews had previous experience from research projects , and they could have performed the interviews differently . this feature could have been minimized by translating the questionnaire to nepali prior to the interviews , which would have facilitated the interviewer asking the questions in a standardized way and thereby avoiding bias . the option to let the women fill out the questionnaire in nepali on their own would probably not have succeeded as most women would have needed help anyway to read and understand the questions . it is important though to clarify that the same doctors and nurses helped conduct the interviews for both cases and controls so any deviations in interpreting the questions should not differ between the two groups , and consequently not impact the comparison performed . another aspect that may have influenced the results of this study is that two of the co - authors were present during the interviews . this could cause bias if the study constructors interpreted aspects of the answers in a direction that would strengthen the hypothesis of the study more than an independent interviewer would have done . however , it was important that the study constructors were present to clarify any ambiguities during the interviews because all patients were not admitted to the ward and thus would be unable to be reached after the interview for clarification . moreover , all questions in the questionnaire , except for the one regarding religious affiliation , had a predetermined alternative set of answers that the interviewees had to choose from . this makes the room for interpretation by the interviewer , and therefore bias , smaller than if the questions had been of a more open character . also , the study constructors did not understand nepali , which makes the risk for a biased interpretation of the answers low . according to the nepal demographic health survey , the most commonly known contraceptive methods in nepal are sterilization , condom , depo - provera , and oral contraceptives . this study showed mostly the same results , the difference being that only 64% of participants in the present study knew about sterilization , including both female and male sterilization , compared to 99% in the national study.1 the number of previous induced abortions of pregnancies and miscarriages was low . there is a possibility that the real number of previous abortions was higher since the women may have wanted to hide abortions done before the legalization in 2002 . also , in 2006 , as many as 50% of women in nepal were still unaware that induced abortions were legal and some of the previous abortions could instead have been reported as previous miscarriages.9 the study was conducted only in kathmandu , the capital , and does therefore not represent the total female population of nepal . features such as education , income , and tradition differ a lot between people living in the suburbs and rural areas , and the material in this study has to be seen only to represent women in kathmandu seeking medical care at kmc . future studies should investigate the knowledge , attitudes , and availability of contraceptives in the rural areas of nepal . a worldwide goal within reproductive health is that all women should have the ability to control their fertility , which requires that they have access to reproductive education , modern contraceptives , and safe abortions.18 this study shows that contraceptive knowledge among nepalese women does not differ significantly between women seeking an induced abortion and a control group . highly educated women knew about more birth control methods , and women in the control group had a higher education . even though this study showed no significant correlation between better contraceptive knowledge and fewer unwanted pregnancies , other studies have done so , and information about family planning should be improved in the health sector and included in general education in nepal to increase the use of contraceptives and thereby avoid unwanted pregnancies . women should not have to wait until after their first , and sometimes unwanted , pregnancy to receive information about birth control . as this study shows that the efficiency of contraceptives is one of the most important features when choosing a birth control method , information about fertilization and how contraceptives work should be a focus when educating people about family planning . a previous study showed that only promoting contraceptive use is not enough , and education about the physiology of reproduction and fertilization is necessary for better compliance.19 when this study was conducted , no difference in contraceptive knowledge was observed between women who had received information from their doctor about birth control and women who had not been informed , suggesting that the information was insufficient . in the future , attitudes about contraceptives have to be further investigated to develop better and more effective methods to inform and educate women on this subject to avoid unwanted pregnancies and increase reproductive health . Output:	objectiveto map the knowledge about and attitudes toward birth control methods among women in kathmandu , nepal , and to compare the results between women seeking an induced abortion and a control group.methodthis was a cross - sectional cohort study with matched controls . women aged 1549 years seeking medical care at the department of gynecology and obstetrics at kathmandu medical college were included and interviewed . a case was defined as a woman who sought an elective medical or surgical abortion . a control was defined as a woman who sought medical care at the outpatient department or had already been admitted to the ward for reasons other than elective abortion . a questionnaire developed for the study dealing with different demographic characteristics as well as knowledge about and attitudes toward contraceptives was filled out based on the interview.resultsa total of 153 women were included : 64 women seeking an abortion and 89 controls . women seeking an abortion had been pregnant more times than the control group and were more likely to have been informed about contraceptives . women with higher education were less likely to seek an abortion than women with lower education . there was no significant difference in knowledge about and attitudes toward contraceptives between cases and controls . the women considered highest possible effectiveness to be the most important feature when deciding on a birth control method.conclusionwomen seeking abortion in kathmandu had shorter education and a history of more pregnancies and deliveries than women in the control group . education and counseling on sex and reproduction as well as on contraceptive methods probably need to be improved in nepal to avoid unwanted pregnancies . attitudes about contraceptives need to be further investigated to develop better and more effective methods to educate women about family planning in order to increase reproductive health .
PubmedSumm118833	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: enrollment in health maintenance organizations ( hmo 's ) increased about 18 percent per year between 1982 and 1984 and 25 percent in 1985 ( interstudy , various years ) . the number of people now enrolled in hmo 's exceeds 21 million , and the number of hmo 's approaches 500 . most new hmo 's are independent practice associations ( ipa 's ) , which account for over 50 percent of all hmo 's . ipa 's also account for over 50 percent of all hmo 's that have risk - based contracts with medicare . selection bias occurs if those who enroll in hmo 's are either more or less likely to use health services after adjusting for factors used to set rates ( e.g. , medicare sets hmo rates based on age , sex , medicaid eligibility , and institutional status ) . if after adjusting for factors used to set rates healthier people join an hmo , then the hmo enjoys favorable selection . if after adjusting for factors used to set rates sicker people join an hmo , then the hmo experiences adverse selection . within each group of enrollees charged the same rate , hmo 's and traditional insurers desire enrollees who use fewer services . there are reasons why high users of medical services within each category might want to join an hmo ( e.g. , hmo 's generally provide more comprehensive benefit packages ) and some reasons why they might prefer to seek care in the fee - for - service system ( e.g. , high users of medical services often have close contact with physicians that they may be reluctant to give up ) . efforts to increase hmo enrollment assume that hmo 's achieve at least some of their cost savings as a result of increased efficiency and not solely because they treat a healthier population . if the latter were true , then increased hmo enrollment would not lower health care costs . although my purpose in this article is to examine the problems that selection bias causes in identifying the true hmo effect on utilization of services , the extent to which other problems are caused by selection bias is an important question . pauly ( 1985 ) states , interest in a policy question such as biased selection usually has some foundation in welfare economics . we want to know whether there is either inefficiency or a transfer of welfare from one set of consumers to another . pauly is not sure that there is any inefficiency associated with self - selection bias in hmo 's . although he acknowedges that , if healthier people within each medicare rate category are more likely to join an hmo , medicare expenditures will increase . this transfer of funds from the general public to hmo 's is viewed by pauly as an equity problem . it is important to distinguish between discussions of adverse selection in conventional insurance markets and biased selection in hmo markets . adverse selection in conventional markets results from commodities exchanged , where the buyer and seller possess different information about the characteristics of a commodity . for example , adverse selection in the health insurance market exists if better risks are attracted to less comprehensive insurance plans and the insurers can not distinguish risk levels . if healthier people within each rate category join an hmo , biased ( favorable ) selection into hmo 's would exist . in this situation , it is not clear whether or not inefficiencies exist because of favorable selection . several studies on how people select health plans recently have been published ( wilensky and rossiter , 1986 ) . most of these studies have found no difference between the health status of hmo enrollees and those in conventional plans ( luft , 1981 ) . yet , a sizable body of research documents that the use of services by people who subsequently join an hmo is significantly lower than that by those who choose to remain in a conventional plan ( luft , 1981 ) . there also is evidence that prior use is a good predictor of future use . in this article , i analyze recent research regarding selection bias in hmo 's , review studies of health plan choice and use , explain recent evidence regarding selection bias of those people 65 years of age or over and the relevance of this issue for administrators of medicare 's hmo program , and examine evidence concerning selection bias for people under 65 years of age . luft 's review of hmo 's in 1981 indicated that hmo 's spend from 10 to 40 percent less to treat enrollees than the fee - for - service sector and that these savings are attributable to the lower hospitalization rates in hmo 's ( luft , 1981 ) . the hmo 's examined by luft experienced 20 to 40 percent fewer hospital admissions per enrollee . another is that the clear economic incentive inherent in hmo 's because of their fixed budget to care for enrollees encourages greater efficiencies in the use of all medical services . luft also suggested that hmo 's may save money because individuals who need and demand fewer health care services are more likely to choose an hmo . if the last explanation is true , then increasing the number of people in hmo 's will not reduce health care costs . people choose health plans based on the attractiveness of the health plan ( i.e. , utility ) . the utility of a health plan to a person is a function of many factors including specific characteristics of the person ( e.g. , age , sex , income , health status , and propensity to consume health resources ) and the health plan ( e.g. , out - of - pocket payments , copayments , deductibles , breadth of coverage , and choice of providers ) . in an equation explaining health plan choice with a discrete dependent variable ( either 0 or 1 according to whether a person joins an hmo ) , selection bias exists if those variables statistically significant in the health plan choice equation representing person characteristics ( e.g. , age , race , income , and health status ) are also statistically significant in an equation explaining the use of health services and these variables are not used to set rates . in addition , it should be noted that selection bias also may result from unobserved variables that arenecessarily excluded from both the choice and expenditure equations . first , studies of health plan choice and use do not limit their data set to individuals facing the same set of options ( i.e. , almost all published studies of health plan choice include single people with no children , single people with children , married people with children and a working spouse with health insurance options , and other categories of people in the same equation ) . no study of hmo versus fee - for - service choice to date has correctly modeled the choice across multiple health plans . the choice set has been restricted , in some cases quite arbitrarily , to two choices . it is unclear how the inclusion of people facing different choices affects estimates of selection bias . second , there are certain factors ( e.g. , a person 's propensity to consume health services ) that can not be directly observed that affect health plan choice and use . in addition for instance , a family may in general be low users of services and belong to a plan with low premiums but higher coinsurance amounts . however , if they anticipate higher use ( e.g. , maternity use ) they may make a change specifically for that reason . third , no study has data on all relevant variables in the health plan choice and use equations . most studies have poor data on health status , and few studies include such variables as the distance to an hmo or waiting times to see a physician . in most studies of health plan choice , characteristics of people at a single site who did or did not join an hmo are compared . usually , these studies are conducted at the time employees are provided a choice between staying in a conventional plan or switching to an hmo . these studies are subject to criticism because they do not correct for the influence of factors that are correlated with each other . , a number of studies based on national data sets and multivariate statistical techniques have been conducted to learn about health plan choice and use ( welch , 1985a ; farley and monheit , 1986 ; welch and frank , 1986 ) . unfortunately , in these studies , not only were different categories of people combined ( single with and without dependents , married with and without working spouse , married with and without dependents , etc . ) but also people who had no choice among plans to choose from ( less than one - fifth of the people in the national medical care expenditure survey had a choice among plans ) were combined with those who could choose among many different kinds of traditional plans and hmo 's . in addition , these studies often do not correct for differences in out - of - pocket premiums , copayments , deductibles , or in the number of covered services . it is impossible to assess the impact of these specification errors on estimates of selection bias . those who hypothesize favorable selection for hmo 's believe that , other things held equal , low - risk individuals are more likely to join an hmo than high - risk individuals . if attachment to a physician is a more important factor than broader coverage for high - risk individuals , then we may expect healthier people to join hmo 's . recent studies reveal that attachments to physicians is one of the most important reasons why people do not join hmo 's . juba , lave , and shaddy ( 1986 ) state that integration in the local medical care system is a dominant factor in the decision to select a particular health plan . families having strong , well - established ties with personal physicians will opt for an insurance plan that preserves these associations . although hmo 's generally provide broader coverage , this has not been found to be a significant determinant of health plan choice . the estimation of selection bias would be a simple task if high - risk and low - risk individuals could be identified prior to the enrollment decision . we could simply count the number of high risks and low risks who joined an hmo to determine whether selection bias existed . if a greater percentage of low - risk individuals joined an hmo most studies use self - assessed measures of health status , the number of chronic conditions , and prior use of health services to identify high risks and low risks . yet , these studies may suffer from self - selection bias if individuals select hmo 's based on factors that are not readily observable ( e.g. , propensity to consume health services may be correlated with health plan choice ) . the rand health insurance study ( manning et al . , 1984 ) was a social experiment that examined the experience of 1,580 persons who were randomly assigned to receive care from the fee - for - service physician of their choice or from the group health cooperative ( ghc ) of puget sound in the state of washington . this experiment , which began in 1974 and ended in 1982 , was not affected by self - selection bias because entrants were randomly assigned to an option . those assigned to the fee - for - service sector ( ghc does not charge for individual services , so it was not practicable to use copayments . ) people were excluded from this experiment if they had high incomes , were eligible for medicaid , or were over 62 years of age . the experiment revealed that expenditures for the ghc group were 25 percent less than the zero copayment ( i.e. , free care ) . this finding was statistically significant and may be explained by ghc 's low hospital admission rate which was 40 percent less than the fee - for - service group with zero copayment . although the rand study provides the strongest evidence to date that in the absence of selection bias hmo 's can achieve savings , several factors mitigate the impact of this study . first , this is a study of only one prepaid group practice hmo at one site . rand ascertained that those people who refused to enter the experiment were similar in some respects to those people who did join the experiment . yet , if those who did not enter the experiment differed systematically from those who entered on the basis of characteristics not observed by the rand analysts , then the results of this study are biased . for instance , it may be that people who were strongly associated with their physicians disproportionately refused to join the experiment and that these people would have required more care whether treated at ghc or in the fee - for - service sector . finally , the difference between expenditures for the fee - for - service enrollees with 25 percent copayment rates and ghc enrollees was not statistically significant . because most fee - for - service plans have copayments in this range , this suggests that transferring enrollees from most fee - for - service plans would not result in cost savings . for several reasons , studies of health plan choice for individuals 65 years of age or over are better specified than studies for those under 65 years of age . they do not face identical fee - for - service options because a substantial proportion of medicare beneficiaries possess supplementary policies . yet , there are more specification problems in a health plan choice equation for the nonaged relating to characteristics of the fee - for - service plan than for the aged . most working people receive health insurance from their place of employment , and people employed by different firms face very different options . it is also common for employees to have a choice among numerous fee - for - service options . second , the choice of health plan for medicare enrollees is rarely confounded by dual choice options and never confounded by choices between self - coverage and family coverage . for those 65 years of age or over medicare does not extend to one 's family , and rarely is the medicare beneficiary covered by a spouse 's health plan . people under 65 years of age generally may choose between self - policies and family policies . this choice is often complicated because the employee may be covered under a working spouse 's health plan . few studies of health plan choice for people under 65 years of age have information on the spouse 's health insurance options . in addition , most studies of those under 65 years of age do not distinguish between those who have only one viable option ( e.g. , family coverage is not a reasonable choice for a single employee with no dependents ) and those with several options . third , all studies of health plan choice involving the aged adjust for differences in age , sex , medicaid eligibility , and institutional status of the beneficiary because the rates hmo 's receive per beneficiary are set according to these variables . studies of health plan choice involving the nonelderly adjust for a variety of different factors . because they are better specified , studies of selection bias in risk - based medicare hmo 's are easier to compare than studies of health plan choice for the nonaged working population . this is fortunate because the potential impact of selection bias for risk - based medicare hmo 's is great . medicare regulations set reimbursement rates for risk - based hmo 's on the basis of the age , sex , medicaid eligibility , and institutional status of the beneficiary . hmo 's are not able to set rates for medicare beneficiaries based on their experience with this group . consequently , hmo 's are liable to the extent they are unable to adjust rates upward if they are losing money . medicare is at risk because it is required to pay a set rate to an hmo even though an hmo may be realizing a profit simply because it has enrolled healthier beneficiaries . to date , medicare has not terminated a risk - based contract because an hmo was making substantial profits on its medicare enrollees . in the remainder of this article recent studies of the health plan choices for individuals 65 years of age or over ( the elderly ) , will be examined , followed by an examination of recent studies of health plan choice for individuals under 65 years of age ( the nonelderly ) . the significance of the choices made are discussed with particular reference to the administration of the medicare program . section 1876 of the social security amendments of 1972 empowered medicare to sign risk - based contracts with hmo 's . group health cooperative ( ghc ) of puget sound was the only hmo with a risk - based contract in 1980 . medicare initiated numerous demonstration projects in the early 1980 's to encourage hmo 's to participate in the medicare program on a risk basis ( u.s . the tax equity and fiscal responsibility act ( tefra ) of 1982 made it more attractive for hmo 's to participate on a risk basis with medicare . it was not until january 1985 , however , that regulations were implemented for this provision of tefra . among other things , these regulations permitted non - federally qualified hmo 's ( referred to as competitive medicalplans ) to contract with medicare on a risk basis . all demonstration projects have been switched under tefra although a few still have waivers for specific requirements . there are more than 830,000 medicare enrollees in risk - based hmo 's and the rate of enrollment is increasing at a rapid rate ( american hospital association , 1987 ) . risk - based hmo 's are paid a set fee for each medicare enrollee , as opposed to providers in the traditional fee - for - service sector and hmo 's that do not sign a risk - based contract . if risk - based hmo 's enroll medicare beneficiaries who are less likely to consume health services , then medicare payments would exceed what they would have paid if all beneficiaries were in the fee - for - service system . also , if better risks join risk - based hmo 's , then payment rates to hmo 's will rise because these rates are based on the cost of providing care to beneficiaries in the fee - for - service sector ( ginsberg and hackbarth , 1986 ) . introduction in congress of the durenberger bill in december 1985 heightened concern about how people select health plans ( u.s . this bill establishes a voucher system to stimulate competition among health plans treating the elderly . there is evidence that care in hmo 's is less costly than care provided in the fee - for - service sector , and those who support a voucher system argue that vouchers would result in the greater use of hmo 's . a voucher system would make fixed per capita payments to qualifying medical plans ( either hmo 's or traditional indemnity insurance plans ) on behalf of medicare beneficiaries who chose the plan . medicare beneficiaries who chose a plan that cost less than the voucher amount would be permitted to keep the difference or use the money to purchase more comprehensive coverage . medicare beneficiaries who chose a plan that cost more than the voucher amount would be required to pay the difference out of pocket . proponents of this policy believe it would increase hmo enrollment because it would enable medicare beneficiaries to share the savings resulting from their decision to join an hmo . presently , most of the benefits of the lower costs experienced by medicare beneficiaries in hmo 's are captured by the medicare program . it was stated in a recent congressional budget office study that each year , barely 50 percent of medicare reimbursements are made on behalf of only 5 percent of enrollees . in 1984 , medicare is concerned that risk - based hmo 's will enroll disproportionately large numbers of beneficiaries who use few or no services . it was concluded from a draft report of the general accounting office ( gao ) that medicare enrollees are healthier than the general population ( the washington post , 1986 ) . the mortality rates of medicare enrollees in 27 risk - based hmo 's were examined . medicare beneficiaries in hmo 's had mortality rates equal to 74 percent of their projected level adjusted for age , sex , medicaid eligibility , and institutional status . the results of this study may be biased , however , because it did not control for geographic variations in mortality . thus , the low mortality of hmo enrollees in florida is at least partly the result of the generally low mortality rates among the aged in florida . the gao did not offer an explanation of why medicare enrollees who shift to hmo 's are healthier , but it did state that there is a potential for hmo 's to screen applicants to enroll healthier individuals . in the gao , it was concluded that , to realize any savings , the rates paid to hmo 's could be no more than 89 percent of the medicare 's adjusted average per capita cost ( aapcc ) for fee - for - service enrollees in thecounty . the aapcc is adjusted for age , sex , medicaid eligibility , and institutional status . new concerns have been raised that ipa 's signing risk contracts with medicare are adept at encouraging those least likely to need health care to join . there is fear that physicians who are members of ipa 's may encourage patients who are low utilizers of health services to join an ipa , and treat patients who are high users of medical services on a fee - for - service basis . it makes economic sense for physicians to enroll the low utilizers of services in an ipa and receive a fixed capitation fee for these enrollees , and treat the high users on a fee - for - service basis . to date , there is little evidence to indicate that this is occurring , and most of the evidence of favorable selection in medicare risk - based hmo 's comes from prepaid group practice hmo 's . there is considerable evidence that enrollees in hmo 's have lower pre - enrollment expenditures than those enrolled in traditional plans . this evidence will be discussed in this article , and evidence that prior use is a good predictor of future use will be examined . the evidence suggests that hmo 's with medicare risk - based contracts experience favorable selection . eggers ( 1980 ) compared 1,000 medicare enrollees at group health cooperative ( ghc ) between october 1976 and july 1979 and 200,000 medicare beneficiaries in the surrounding six - county area . he found that the ghc medicare enrollees had a hospital use rate of over 50 percent below the control group after controlling for age , sex , medicaid eligibility , and institutional status . in another study , eggers and prihoda ( 1982 ) reviewed the experience of medicare enrollees in the fallon community health plan in massachusetts , the kaiser permanente in portland , ore . comparison groups were composed of a 5-percent sample of medicare beneficiaries living in the hmo catchment areas . the fallon community health plan is a one - group staff model that signed up about 5,000 medicare beneficiaries under a risk - demonstration project . the inpatient hospital reimbursement rates for medicare beneficiaries at fallon were between 18 and 32 percent below the comparison group for the years 1976 through 1980 , and the part b reimbursements were between 8 and 18 percent less . inpatient hospital reimbursement levels for medicare enrollees at kaiser permanente were between 10 and 30 percent below its comparison group for this period . the greater marshfield community health plan is located in rural wisconsin and services 53,000 residents . it is a group - practice hmo that employs most of the physicians in the marshfield area . these physicians retain their private offices and many treat patients on a fee - for - service basis . the inpatient hospital reimbursement rate for medicare enrollees at marchfield ranged from 8 to 15 percent higher than the comparison group . eggers and prihoda hypothesized that , because marshfield employs almost all physicians in the area , it does not employ the same degree of favorable selection found at traditional type , group - practice hmo 's . it has been shown in other studies that prior use is a good predictor of future use . anderson and knickman ( 1984 ) studied the records of 200,000 medicare beneficiaries during 1974 and 1975 . they found that beneficiaries hospitalized in 1974 were more than twice as likely to be hospitalized in 1975 than beneficiaries not hospitalized in 1974 . in a similar study , anderson , resnick , and gertman ( 1982 ) used records of medicare beneficiaries in los angelescounty between 1974 and 1977 to demonstrate that prior use is a good predictor of future use . eggers ( 1981 ) used records from a sample of 13,000 beneficiaries in 1978 and 1979 to demonstrate the power of prior use to predict future use . he showed that the coefficient for the level of reimbursement for health services for a beneficiary in 1978 was more than five times as large as the coefficients for age and sex in an equation explaining the level of reimbursement in 1979 . mccall and wai ( 1985 ) examined a sample of 4,300 medicare beneficiaries from 1974 to 1978 and stated that , we find consistent high users of services who consume substantial portions of total expenditures and consistent nonusers having none or few services . studies of individuals under 65 years of age also reveal that prior use is a good predictor of future use . densen , shapiro , and einhorn ( 1959 ) and mullooly and freeborn ( 1979 ) examine those under 65 years of age and show that individual utilization patterns are consistent over time . in a recent article by welch ( 1985b ) regression toward the mean is the tendency of a variable to move towards its mean over time , and it was originally observed in offspring of tall parents ( i.e. , offspring of tall parents were not as far above the mean as their parents ) . welch argues that the assumption that last year 's medical expenditure is an unbiased estimation of this year 's expenditure is incorrect . from the rand health insurance experiment and the mccall and wai studies , he finds that autocorrelation of expenditures adjusted for age , sex , and other stable characteristics is about .2 . he concludes that , if medicare beneficiaries who enroll in a risk - based hmo have annual expenditures $ 500 less than beneficiaries who do not enroll , the expected difference in the following year is about $ 100 ; and this difference is expected to fall in subsequent years . although welch presents a compelling argument , there are several reasons to be skeptical about his conclusion . first , welch used estimates of autocorrelation obtained from the rand health insurance experiment and mccall and wai studies . yet , the error components model used in these studies is quite restrictive ; and it assumes that the correlation of error terms over time remains unchanged , regardless of how far apart in time the error terms are ( i.e. , that first , second , third , and higher order autocorrelations are equal ) . mccall and wai found that the probability that a nonuser of health services in 1975 would be a nonuser in 1976 was 63 percent , in 1977 it was 54 percent , and in 1978 it was 44 percent . this suggests that autocorrelation decreases over time and that the disturbance term in the error component model should be modeled using some scheme where the disturbance term in the current period is a function of the disturbance term in the prior period ( i.e. , where first , second , third , and higher order autocorrelation are not equal ) . ellis ( 1986 ) found that correlation between total covered costs in 1982 and 1983 for a sample of 13,816 non - hmo enrollees was .541 . congress , 1982 ) and andersen and knickman ( 1984 ) show that the expenditures of high and low users in 1 year regress towards the mean in subsequent years . welch uses this evidence to conclude that the low users who join hmo 's would have incurred higher expenditures in subsequent years . this is true only if the group of low users who join hmo 's is a random sample of all low users . it may be that the group of low users who join hmo 's are consistently low users over time . luft 's book on hmo 's contains a good review of the evidence on selection bias available in 1981 ( luft , 1981 ) . at that time because there were no studies of selection bias using data from this hmo , luft 's review of selection bias in hmo 's pertains to the nonelderly . luft found that surveys that compare characteristics of hmo and non - hmo enrollees reveal few systematic differences between the health status of these two groups . luft also found that data on people who subsequently joined hmo 's revealed that these people were lower users of hospital care than those who chose to remain in a conventional plan . luft reconciles these apparently conflicting observations by hypothesizing that there are two factors at work . he reasons that when hmo out - of - pocket premiums are high they attract generally sicker people who anticipate substantial usage of hmo services and that people who have strong ties with physicians ( generaly sicker people ) are less likely to join an hmo . however , they do not explain why before - and - after studies of expenditures find evidence of selection bias and why studies of health status of hmo and non - hmo enrollees find no evidence of selection bias . the studies reviewed by luft were descriptive , and they contained simple comparisons of the characteristics of those who did and did not join an hmo . multivariate statistical techniques were used in more recent studies of selection bias to analyze how people choose among hmo 's and traditional health plans and how this choice affects the utilization of health services . multivariate statistical techniques are designed to isolate and estimate the effect of each variable and to take into account the correlation among explanatory variables . several of these studies are based on national data . in general , the results found by luft are confirmed in recent studies , most of which reveal that hmo enrollees experience lower health expenditures during the period prior to joining an hmo than those who remain in traditional plans . in addition , in most recent studies , it was found that the health status of hmo and non - hmo enrollees is about the same . grazier and others ( 1986 ) found little or no difference in prior use between those who chose an ipa in seattle and those who remained in the fee - for - service plan . dowd and feldman ( 1986 ) found the health status of hmo enrollees in the twin cities to be better than enrollees in traditional plans . health status in this study was defined as the presence of chronic conditions . in the following paragraphs , we discuss some of the studies that confirm luft 's findings . in their studies , 1977 ) , jackson - beeck and kleinman ( 1983 ) , and buchanan and cretin ( 1986 ) show that people who enrolled in prepaid group practice hmo 's used fewer health care services than people who remained under traditional plans during the period prior to enrollment . , who had the option of enrolling in a prepaid group practice hmo , an ipa , or remaining under a traditional plan in 1975 . substantial favorable selection bias was found in the prepaid group practice plans and unfavorable selection bias was experienced by the ipa . persons joining the ipa used 13 percent more days in 1972 than those who remained in the fee - for - service plan . jackson - beeck and kleinman ( 1983 ) analyzed data on 57,684 people employed by 11 firms in the twincities area who were given an option in 1978 of joining an hmo . the group exiting to an hmo experienced 53 percent fewer hospital days per capita than the group that stayed with a traditional fee - for - service plan . buchanan and cretin ( 1986 ) analyzed data on about 30,000 employees of a large aerospace firm in california and arizona who , between 1978 and 1982 , were offered a choice between one of two hmo 's and a fee - for - service plan underwritten by the firm . the authors conclude that , when premium differentials are modest ( as they are in this case ) , single employees and younger families with lower total claims may opt for an hmo . this finding persisted even after pre - hmo enrollment expenditures were adjusted for age and sex . in studies by grazier et al . ( 1986 ) , welch and frank ( 1986 ) , and welch , frank , and diehr ( 1984 ) , it is shown that the health status of hmo enrollees is about the same as that of enrollees in traditional health plans . in their study , grazier et al . analyzed data from a sample of 2,000 families of washington state employees who were members of blue cross of washington and alaska or the group health cooperative of puget sound . these employees were offered the option of joining an ipa type hmo , united healthcare , in 1978 . found that , the physical health status measures were similar between blue cross and group health cooperative groups and did not appear to affect change - of - plan decisions . physical health status is measured by self - perceived assessments ( excellent , good , fair , or poor ) and by the number of chronic conditions . welch and frank used logit analysis to study the health plan choices of people in the national medical care utilization and expenditure survey , a national sample of the civilian , noninstitutionalized population collected by the national center for health statistics in 1980 . the authors created one observation per family with the variables age , education , and insurance coverage pertaining to the head of household . the only significant variables in the health plan choice equation were income and hmo percent of market share . self - perceived health status and the number of chronic conditions were not related to health plan choice . welch , frank , and diehr studied a sample of people in a section of seattle who were given a choice between ghc and blue cross of washington and alaska . the sample was limited to persons under 65 years of age who were not on public assistance and whose income did not exceed the poverty level by more than $ 2,000 ( i.e. , the medically needy ) . choice equations were estimated using logit techniques , and a multistage selection technique developed by heckman , lee , and olsen was used to estimate the effect of hmo choice on utilization . the authors concluded that , where health is assessed by self - measurement and the number of chronic conditions , there is little evidence that the healthy disproportionately selected ghc . the results found by luft and confirmed in most recent studies ( i.e. , that self - assessments of health status and the number of chronic conditions do not vary significantly between those who join and those who do not join an hmo ; those who joined hmo 's used fewer health services than those who did not join an hmo during the time period prior to the enrollment decision ) , make it difficult to generalize about selection bias in hmo 's . one way of interpreting these findings is that hmo 's attract people whose propensity to use health services given a specific health state is less than those who do not joinan hmo . part of the logic behind hmo 's is their emphasis on preventive medicine and health maintenance . emphasizing preventive services may be good marketing strategy not only because it attracts new enrollees , but because it attracts enrollees who are parsimonious users of medical services . if this were true , hmo enrollees might not possess better measures of health status than enrollees in conventional plans , but they would demand fewer health services . in other words , although there may be no difference in need ( i.e. , health status ) , there seems to be a difference in the propensity to consume health services as evidenced by the demand for health services . this reasoning hypothesizes the existence of an unobservable variable ( propensity to consume health services given a specific health state ) that affects both the decision whether or not to join an hmo and the quantity of health care services consumed . a new statistical technique pioneered by heckman , lee , and olsen is designed to take into account the impact of unobservable variables on estimates of selection bias in hmo 's ( heckman , 1979 ; lee , 1978 ; olsen , 1982 ) . first , analysts who have used it have found that estimates using the correction factor lack robustness ( i.e. , small changes in the specification of the expenditure equation yield substantial changes in estimates ) and often do not make sense ( welch , frank , and diehr , 1984 ) . it hypothesizes the existence of a linear choice function where all people who join an hmo have positive values for this function and that the error term in this function is normally distributed with mean zero . this technique also assumes that error terms in the choice and expenditure equations are bivariate normal . because of these concerns , it is still an open question of whether selection bias attributable to unobserved variables can be addressed adequately without conducting a randomized experiment . review of the available literature leads one to conclude that prepaid group practice hmo 's do experience favorable selection . numerous studies demonstrate that prior use of health services for hmo enrollees is less than prior use of health services for those who remain in the fee - for - service sector . there is considerable evidence that shows a statistically significant positive relationship between prior use and current use . these findings reflect the experience of hmo 's with both the elderly and nonelderly populations . available evidence indicates that the health status of those who join hmo 's is not significantly different from those who choose a traditional health plan . health status in these studies is measured by self - assessments and the number of chronic conditions . this can be reconciled with the finding that hmo enrollees experience lower use of health services during the period prior to the enrollment decision by hypothesizing that , for a given health status , those who join an hmo are more conservative users of medical services than those who do not . hmo 's stress their commitment to preventive care and health maintenance , and this may attract enrollees who are more conservative users of health services . there is concern about the potential impact of selection bias in medicare risk - based hmo 's , and a recent study by the u.s . general accounting office ( 1980 ) indicates that ipa 's and prepaid group practice hmo 's with medicare risk - based contracts do experience favorable selection . medicare is currently funding an evaluation of about 25 risk - based hmo 's , and this evaluation is examining the issue of selection bias . little is known about the consequences of selection bias in hmo 's on the performance of the market for health services . does selection bias in hmo 's affect the ability of the market to achieve a stable equilibrium ? in addition , there is a dire need for more information on the extent of selection bias in ipa 's . it would also be interesting to know whether selection bias in hmo 's varies with the proportion of people enrolled in hmo 's in different areas ( e.g. , does selection bias decrease as the percent of people in hmo 's increase ? ) . in addition , it would be interesting to know how the absolute level of the difference between the hmo and fee - for - service premiums affects selection bias . presumably , favorable selection bias into hmo 's decreases as hmo premiums increase relative to fee - for - service premiums . research in these areas is needed to enable policy analysts to learn about the extent of selection bias in hmo 's and its impact on the market for health services . Output:	an analysis of recent research regarding selection bias in health maintenance organizations ( hmo 's ) is presented in this article . review of the available literature leads one to conclude that prepaid group practice hmo 's do experience favorable selection . it has been demonstrated in numerous studies that prior use of health services by hmo enrollees is less than prior use of health services by those who remain in the fee - for - service sector , and there is considerable evidence that shows a statistically significant positive relationship between prior use and current use . this is true for both those under 65 years of age and those 65 years of age or over .
PubmedSumm118834	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: cyclin dependent kinase-5 ( cdk5 ) , a family member of the cyclin dependent kinases , plays a pivotal role in the nervous system development and function . cdk5 was first purified as one ( tpkii ) of two tau protein kinases , namely tpki and tpkii , from a bovine brain microtubule fraction ( ishiguro et al . , 1992 ) , as neuronal cdc2-like kinase from bovine brain extracts ( lew et al . , 1992 ) , and as a lys - ser - pro ( ksp ) sequence phosphorylating kinase from rat spinal cord ( shetty et al . , 1993 ) . we had also identified kinase and phosphatase players regulating neurofilament and tau phosphorylation in mammalian and squid neurons ( floyd et al . , 1991 ; veeranna et al . , 1998 ; veeranna et al . , 2000 ; grant and pant , 2004 ) , identified cdk5 as a principal kinase phosphorylating ksp sites in neurofilament subunit ( nfh ) tail domains ( sharma et al . , 1998 ) , and in a collaborative study of a cdk5 knockout , demonstrated its key role in neuronal development , function and survival ( ohshima et al . , 1996 ) . initially , its activity was found to be restricted to neurons in the central nervous system due to the expression of neuronal specific activators p35 and p39 . however , in the last decade p35 distribution and cdk5 activity have been found in a growing number of tissues such as the testis , pancreas , cornea and most recently in glial cells of the brain ( kesavapany et al . , 2007 ) . the tight regulation of cdk5 activity is achieved through the specific cellular localization of its major activator p35 . with an n - terminal myristoylation sequence of the activator , which anchor the membranes , when a neurotoxic insult involving amyloid- peptides , 1-methyl-4-phenyl-1 , 2 , 3 , 6-tetrahydropyridine ( mptp ) , reactive oxygen species ( ros ) or glutamate is initiated , there is an increase in intracellular calcium , which then activates the calcium - dependent protease calpain . calpain cleaves p35 into a p10 product that is still anchored to the membrane and a p25 moiety that is a potent hyperactivator of cdk5 . p25 is now free to move around the neuronal compartments and the net effect is that cdk5 is hyperactivated by p25 leading to hyper phosphorylation of the substrates . to confound the misery of the neuron , p25 has a very strong affinity to cdk5 but also has a longer half - life than its parent p35 protein , which leads to an aberrant hyperactivation of cdk5 ( kesavapany et al . , 2007 ) . the result of this is an abnormal phosphorylation of cytoskeletal proteins , such as the microtubule - associated protein tau and neurofilaments ( nfs ) and the hyperphosphorylation of these cytoskeletal proteins are found in pathological hallmarks of a number of neurodegenerative diseases including alzheimer 's disease ( ad ) , parkinson 's disease ( pd ) and amyotrophic lateral sclerosis ( als ) . one type of such lesion in ad is the neurofibrillary tangles ( nfts ) where the epitopes found to be phosphorylated in these inclusions are readily hyperphosphorylated by cdk5/p25 . lewy bodies , the inclusions found in pd brain , contain deposits of -synuclein and phosphor nf - h ( hill et al . , 1991 ; spillantini et al . , 1997 ) and cdk5 ( brion et al . , 1995 ; nakamura et al . , 1997 ; smith et al . , 2003 ) , while inclusions in the spinal cord contain hyperphosphorylated aggregated nf - h ( bajaj et al . , 1998 , 1999 ) . in pd , early involvement of cdk5 in the disease pointed to its presence in lewy bodies ( nakamura et al . , 1997 ) . since then , experiments using mptp to induce dopaminergic neuronal loss showed that the downstream effector of this is cdk5 ( smith et al . , calpains produces p25 and hyperactive cdk5 ( cdk5/p25 ) phosphorylates the transcription factor myocyte enhancer factor 2 ( mef2 ) to inactivate it . the inactivation of mef2 causes neuronal loss ( smith et al . , 2006 ) . in a recent report , cdk5 has been shown to interact with and phosphorylate parkin , a protein that contains e3-ubiquitin ligase activity . mutations in parkin are responsible for a large percent of autosomal recessive juvenile parkinsonism cases . cdk5 phosphorylation of parkin decreased its auto - ubiquitination activity and a phospho - deficient mutant of parkin displayed increased ubiquitination towards itself as well as its substrates synphilin and -synuclein , both constituents of lewy body inclusions in pd . the results showed that cdk5 activity is important in regulating inclusion formation and accumulations of toxic parkin substrates in a pd paradigm ( avraham et al . , 2007 ) . current strategies to produce inhibitors of kinase activity target atp binding regions of the kinases . however , since all kinases depend on these regions as a mode of action , the specificity of this approach has often been called into question . normal p35-mediated cdk5 activity , as mentioned before , is required for the proper formation and function of the nervous system and thus , only aberrant p25-mediated cdk5 hyperactivity must be targeted and atp analogues would not be useful in this paradigm . indeed , known inhibitors such as butyralactone , olomoucine and roscovitine all inhibit normal as well as aberrant cdk5 activity . while attempting to fully characterize the behavior of p25 and its subsequent hyperactivation of cdk5 , we identified cip ( 126a.a . residues ) , a truncated fragment of the cdk5 regulator , p35 , which specifically inhibited hyperactive cdk5/p25 ( amin et al . , 2002 ; sundaram et al . , 2013 ) , presumed to contribute to the pathology of ad ( patrick et al . , 1999 ; a further fine - tuning of these studies has identified a smaller , 24-aa peptide ( termed p5 ) derived by serial truncation of cip . this 24-aa peptide ( termed p5 ) has been shown to inhibit cdk5/p25 activity in transfected human embryonic kidney 293 ( hek ) cells and primary neurons without affecting normal cdk5/p35 or other cdks ( zheng et al . , 2002 , 2005 , 2007 , 2010 ; kesavapany et al . , 2007 ) . subsequently , p5 , modified as tfp5 so as to penetrate the blood - brain barrier after intraperitoneal injections in ad model mice , inhibited abnormal cdk5/p25 hyperactivity and significantly rescued ad pathology in ad model mice ( shukla et al . , 2013 ) . moreover , tfp5 also reduced toxicity in cortical neurons exposed to high glucose ( binukumar et al . , 2014 ) . encouraged by our previous results and cdk5 involvement in pd , cdk5/p25 has been identified as a prime therapeutic target for pd . in a recent study the efficacy of the tfp5 peptide was tested in a pd model ( binukumr et al . , 2015 ) . consistent with previous studies , we observed 24 hours of mpp incubation induces cdk5 hyperactivation in mesencephalic primary cultures . pretreatment and coincubation with tfp5 , however , was sufficient to significantly reduce the elevated activity . because the cdk5/p25 inhibitor tfp5 was effective at blocking deregulated kinase activity , we further tested whether the effect can be replicated in primary dopaminergic neurons from mesencephalic cultures . the number of tyrosine hydroxylase ( th ) positive neurons and the length of th - positive neurites were significantly reduced after mpp treatment . in contrast , treatment with tfp5 effectively attenuated mpp induced toxicity in dopaminergic neurons . scrambled peptide control however , had no protective effect on these cells . taken together , those results demonstrate that tfp5 has a neuroprotective effect in cell culture models of dopaminergic neurodegeneration . we also investigated the anti inflammatory action of tfp5 , primary neuron - glia cultures from mouse midbrains with tfp5 or scrambled peptide . it is evident that treatment with mpp increased the expression of both f4/f8 and gfap , astocytic marker compared with the control , whereas treatment with tfp5 ameliorates these effects . further we examined the effect of tfp5 on mpp induced apoptosis by measuring caspase-3 activation and cytochrome c release in the mixed cultures . treatment of mesencephalic primary cultures with mpp for 24 hours resulted in robust activation of caspase-3 and cytochrome c release . tfp5 significantly inhibited the increased levels of caspase-3 and cytochrome c. to confirm further the antiapoptotic function of tfp5 , we determined the expression levels of bcl-2 . this result is in line with previous reports ( liu et al . , 2010 ) . treatments with tfp5 significantly increased bcl-2 expression . together , these results showed that tfp5 treatment has antiapoptotic effects in mesencephalic primary culture . as a more effective test of the efficacy of tfp5 as a therapy for pd , we used an in vivo model system . for the initial sets of experiments , animals were injected intraperitoneally ( i.p . ) with a single tfp5 injection , 40 mg / kg every day for 9 days . on day 2 , tfp5-treated animals received four doses of mptp . we found that the dose of tfp5 was inadequate ; tfp5-treated animals did not show significant inhibition of cdk5/p25-deregulated activity compared with the mptp group accordingly , we increased the dose to a single , 80 mg / kg i.p . we used the peptide without the fitc tag ( tp5 ) since tfp5 aggregates at higher concentration . in this case , tp5 pretreatment produced significant inhibition of cdk5/p25 kinase activity . mptp treatment also reduced the number of th - positive neurons by 77% compared with saline - treated controls . mice that received daily treatments of tp5 at 80 mg / kg showed an increase of th - positive neurons in the snpc . the neuroprotective effect of tp5 was dose dependent , as a 40 mg / kg dose of tp5 failed to protect dopamine neurons due to mptp toxicity . moreover , mptp injections also caused significant decreases in the level of dopamine and its metabolites in the striatal region of mptp - injected mice . mptp - induced dopamine and homovanillic acid ( hva ) depletion was attenuated almost to control levels in mice treated with tp5 . taken together , these results suggest that tp5 can improve neurochemical deficits in the mptp mouse model of pd . microglial activation has been implicated in the propagation of snpc neurotoxicity in multiple animal models of pd . post - mortem analysis of idiopathic pd patients revealed strong immunoreactivity for cd68 , a marker of phagocytic microglia ( croisier et al . administration of mptp has been reliably shown to induce this phagocytic microglia phenotype in the snpc of mice ( vroon et al . previous studies reported in addition the presence of reactive microglia in mptp - treated sn exhibiting nigral da neuronal degeneration ( wu et al . , 2003 ; block et al . , 2007 ) . accordingly , we investigated whether a tp5 injection regimen can inhibit mptp - induced glial activation in the snpc in vivo . consistent with earlier reports ( wu et al . , 2003 ) , numerous gfap - positive reactive astrocytes and cd11b - positive ( activated ) microglia were observed in mptp - treated snpc compared with saline and scrambled peptide controls . post - mortem analysis of human pd tissue showed that microglia are immunoreactive for multiple proinflammatory cytokines , including tumor necrosis factor ( tnf- ) and interleukin-1 ( il-1 ; mcgeer and mcgeer , 2004 ) . further , mice that are genetically altered to inhibit cytokine production or are deficient in receptors for these cytokines provide neuroprotection in the snpc after mptp exposure ( klevenyi et al . , 1999 ; thus we examined whether mptp - induced expression of il-1 and tnf- in the sn was affected by tp5 . the results showed that the levels of tnf- protein and il-1 were significantly increased in the midbrain of mptp - treated mice compared with saline controls . treatment with tp5 inhibited these mptp - induced effects , reducing levels of tnf- and il-1 ~50% we observed a marked decrease in total distance traveled after mptp treatment ( 85% ) , which was restored ~30% after tp5 treatment . our recent data for the first time identify that intraperitoneal injection of peptide , tp5 into mptp - induced mice effectively blocks degeneration of dopamine neurons in the snpc and prevents the loss of striatal dopamine and its metabolites . the peptide treatment also ameliorates the mptp - induced behavioral deficits , inhibits neuroinflammation in vivo , and protects against mpp neurotoxicity in vitro . these results suggest that tfp5/tp5 may be effective in the treatment of parkinson 's disease . Output:	cyclin - dependent kinase 5 ( cdk5 ) is a member of the serine - threonine kinase family of cyclin - dependent kinases . cdk5 is critical to normal mammalian nervous system development and plays important regulatory roles in multiple cellular functions . recent evidence indicates that cdk5 is inappropriately activated in several neurodegenerative conditions , including parkinson 's disease ( pd ) . pd is a chronic neurodegenerative disorder characterized by the loss of dopamine neurons in the substantia nigra , decreased striatal dopamine levels , and consequent extrapyramidal motor dysfunction . during neurotoxicity , p35 is cleaved to form p25 . binding of p25 with cdk5 leads deregulation of cdk5 resulting in number of neurodegenerative pathologies . to date , strategies to specifically inhibit cdk5 hyperactivity have not been successful without affecting normal cdk5 activity . here we show that inhibition of p25/cdk5 hyperactivation through tfp5/tp5 , truncated 24-aa peptide derived from the cdk5 activator p35 rescues nigrostriatal dopaminergic neurodegeneration induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine ( mptp / mpp+ ) in a mouse model of pd . tp5 peptide treatment also blocked dopamine depletion in the striatum and improved gait dysfunction after mptp administration . the neuroprotective effect of tfp5/tp5 peptide is also associated with marked reduction in neuroinflammation and apoptosis . here we show inhibition of cdk5/p25-hyperactivation by tfp5/tp5 peptide , which identifies cdk5/p25 as a potential therapeutic target to reduce neurodegeneration in pd .
PubmedSumm118835	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: uterine leiomyosarcoma ( lms ) is a rare diagnosis and the majority of cases are diagnosed after surgery for uterine fibroid disease . these patients are often observed for long periods of time , and not infrequently percutaneous embolization is utilized in an effort to avoid surgery for large symptomatic fibroid disease . hysterectomy is usually performed only when the fibroids become excessively symptomatic with pain or bleeding . more recently the potential negative effects of uterine morcellation with fibroid surgery have been described in consideration of this rare entity . the incidence of uterine lms is unusual and represents about 1% of all uterine malignancies [ 3 , 4 ] , and the vast majority of cases are generally confined to the uterus and cervix at the time of diagnosis [ 57 ] . uterine lms must be distinguished from other mesenchymal tumors , such as endometrial stromal sarcoma , adenosarcoma , carcinosarcoma , epithelial tumors , and dedifferentiated mixed tumors as the biology , patterns of recurrence , overall behaviors , and response to treatment are distinct from each other [ 810 ] . hence , a separate figo classification identifies uterine lms as entity from the other types of uterine malignancies ( table 1 ) . and although the differences in staging between uterine lms and endometrial stromal sarcoma are subtle , the staging classification between these two diseases is distinct . in this report we examine only those cases with histologically documented recurrent uterine lms in an attempt to establish prognostic factors for survival in these patients . uterine lms is an aggressive disease and survival after initial diagnosis has been reported to be 50% in stage 1 and stage 2 disease and dismal in advanced - stage disease [ 1215 ] . the most important prognostic factor is stage , followed by age , mitotic count , and tumor size [ 8 , 16 ] . adjuvant therapies such as chemotherapy and radiation seem to have little effect on overall survival [ 8 , 1719 ] . the role of radiation therapy is extremely limited as it has only been examined in the adjuvant setting after the initial diagnosis and has been associated with decreased local recurrence but has no effect on overall survival [ 8 , 1719 ] . chemotherapy , such as dacarbazine , gemcitabine , and docetaxel , has been associated with slightly improved survival [ 18 , 20 ] ; however , the role of adjuvant medical therapy with recurrent disease is almost negligible . in most patients with extrauterine disease , recurrence occurs within 6 to 18 months from the initial diagnosis [ 4 , 21 , 22 ] and surgery seems to be the only treatment that has been demonstrated to improve survival in patients with resectable recurrent disease . despite the limited data in this regard [ 9 , 22 , 23 ] survival of patients with recurrent disease is poor ; however , secondary cytoreductive surgery did show benefits in selected patients with pulmonary , abdominal , and pelvic surgery [ 2123 ] . median survival of patients after secondary cytoreductive surgery was 71% at 2 years and a median survival of 2 years versus 1.1 years in comparison to those only treated medically . prolonged disease - free interval and complete tumor resection were associated with longer survival [ 22 , 23 ] . the overall survival is examined in order to ascertain possible factors that contribute to improved outcomes . all patients who underwent resection for the first recurrence of uterine lms were reviewed from an ongoing retrospective database over a 16-year period from 1997 to 2013 and approved by the institutional review board at our institution . comprehensive data was collected , including age , date of initial diagnosis , tumor histology and grade , stage , size , adjuvant therapies , and followup disease status from the initial diagnosis as well after surgery for recurrent disease . the pathology slides from the initial diagnosis were reexamined and the diagnosis of uterine lms was verified , while definitively excluding epithelial tumors , carcinosarcomas , endometrial stromal tumors , adenosarcomas , and undifferentiated uterine sarcomas . slides from the initial surgery were also compared to the specimens from the recurrent surgery and examined for histologic changes in cellular atypia and more aggressive patterns in appearance and alterations in tumor heterogeneity . staging at the time of the initial diagnosis was applied using the revised international federation of gynecology and obstetrics ( figo ) staging system specifically for uterine lms . the time of first recurrence was calculated from the time of the initial surgery to the date of the surgical resection of the recurrence . preoperative imaging was evaluated and only patients who were considered to have resectable disease underwent surgery . postresection survival was determined from the time of the first recurrence to the last followup . complete resection without evidence of macroscopic disease and microscopically negative tumor margins on final pathology was defined as a complete resection . residual disease was defined as microscopic disease on final pathology and incomplete tumor removal was defined as known macroscopic disease not removed at the time of surgery for the first recurrence . a total of 9 variables were analyzed for possible prognostic value . these included extent of surgical resection , initial tumor stage by figo , time to first recurrence , tumor grade , type of procedure , site of first recurrence , single versus multiple recurrences , local versus distant recurrence , postoperative adjuvant therapy after initial diagnosis ( none versus chemotherapy and/or radiation ) , and adjuvant therapy after recurrence . survival curves were estimated using kaplan - meier method and p values were generated using the log rank ( mantel - cox ) ratio as described by mantel . all statistical analyses were performed using spss software ( spss , version 20 , ibm , chicago , illinois , usa ) . a total of 24 patients were operated on for recurrent metastatic uterine lms with a median age of 57 years ( 37 to 82 years ) . single tumor recurrence occurred in 12 ( 50% ) patients while the others ( 50% ) had 2 or more lesions . overall survival was 2.6 years and survival at 2 , 5 , and 10 years was 57% , 24% , and 12% , respectively . surgery included abdominal , pelvic , and thoracic surgery either alone or in sequence if the metastases were considered resectable . surgery alone , either abdominal or thoracic , was performed in 10 ( 42% ) patients , while 14 ( 58% ) others had a combination of surgery plus chemotherapy ( n = 13 ) and the addition of radiation preoperatively in 1 ( 4% ) other . complete resection , with microscopically confirmed negative margins on final pathology , was achieved in 16 ( 67% ) patients . of those with isolated recurrences 4 ( 16% ) had isolated lung resections , 4 ( 16% ) had intestinal resections , 2 ( 8% ) had partial hepatectomies , 1 ( 4% ) had distal pancreatectomy , and 1 ( 4% ) had complete psoas muscle resection . in patients that had multiple site recurrences 5 ( 20% ) had multiple lesions resected from the pelvis ( urinary bladder , rectum , and colon ) , 4 ( 16% ) had multiple intra - abdominal intestinal resections , 1 ( 4% ) had colon and liver resection , 1 ( 4% ) had colon and lung resection , 1 ( 4% ) had bladder and lung resection , and 1 ( 4% ) other had liver and lung resection . there was one ( 4% ) operative death and 6 ( 25% ) other nonfatal complications . of the nonfatal complications 3 ( 12% ) had prolonged small bowel ileus , 1 ( 4% ) with a small bowel fistula that resolved with expectant management , 1 ( 4% ) with sepsis , and 1 ( 4% ) who had a permanent foot drop from peroneal nerve resection for recurrence involving the psoas muscle . there were 4 ( 17% ) patients with low - grade tumors and 20 ( 83% ) which were high grade . the grade at the time of the initial diagnosis did not have a significant impact on survival . however , 5 ( 21% ) patients had documented histologic change in the aggressiveness of the cytologic characteristics and cellular atypia at the time of recurrence , which was significantly different when compared to the histologic slides from the initial diagnosis . three of the four patients with initial low - grade tumors became high grade , and 2 other patients with initial high - grade tumors had significantly more aggressive appearance on cytologic examination after surgery for the recurrence . these more aggressive forms of leiomyosarcoma were also strongly associated with a trend towards decreased survival ; however , in comparison to those that had no change in cytopathologic features , the difference did not reach statistical significance . the clinical characteristics of the patients at the time of the initial diagnosis and at the time of the first recurrence are listed ( table 2 ) . the median time to first recurrence was 26 months ( range : 1 to 184 months ) from the initial diagnosis of lms , and the median followup after surgical resection for first time recurrence was 34 months ( range : 2 to 89 months ) . overall survival from the time of recurrence is presented ( figure 1 ) with the specific variables listed separately ( table 3 ) . comparing local versus distant recurrences resulted in no significant difference in survival ( p = 0.6 ) . patients with isolated lung metastases after thoracic surgery did not have survival statistically different from the others ( p = 0.89 ) . however , a negative histologic margin in those with documented complete resections in 16 ( 67% ) patients had significantly better survival when compared to those who had microscopic and macroscopic residual disease ( figure 2 ) . at last followup a total of 5 ( 21% ) patients were alive , of which 3 ( 13% ) were alive without disease . also , figo staging of uterine lms at initial time of diagnosis did have a predictive impact on overall survival . when we compared figo stage i to figo stages ii , iii , and iv those with earlier stage i disease had significant increased 2-year survival of 77% versus 30% ( p = 0.01 ) ( figure 3 ) . time to first recurrence greater than 12 months ( figure 4 ) significantly affected survival with a median survival of 25 versus 3 months for those diagnosed with a greater time interval between the initial diagnosis and the first recurrence ( p = 0.006 ) . it is worth noting that all patients that recurred within 12 months had high - grade tumors at initial diagnosis . single tumor recurrence significantly affected survival ( figure 5 ) with a median survival of 119 months for single lesions versus 10 months for those with 2 or more tumors ( p = 0.015 ) . overall median disease - free survival was 14 months and overall median survival was 27 months . at last followup , 2 patients were alive without evidence of disease , 3 were alive with evidence of disease , and the 19 others died from their disease . of the long - term survivors there were 3 ( 13% ) patients that had recurrence more than 5 years after the initial diagnosis and these patients demonstrated the longest survival of the whole group . patient 1 recurred 15 years after her initial diagnosis of a low - grade uterine leiomyosarcoma with an isolated lung lesion consistent with her primary cancer . patient 2 with low - grade disease had her first recurrence 6 years after initial diagnosis . she ultimately experienced multiple localized recurrences , which were treated with subsequent surgeries ; however , she died of disease 16 years after her initial diagnosis . patient 3 with initially diagnosed high - grade tumor had a first recurrence 6 years later involving the distal pancreas and another lesion on the soft tissue of the posterior chest wall . she later recurred with an isolated tumor in the remnant head of the remnant pancreas but refused further treatment . she remains alive with disease 10 years after her initial diagnosis . in all three of these long - term survivors the type of procedure performed , the site of first recurrence , and the use of adjuvant therapy either at the time of the initial diagnosis or after the recurrence had no significant impact on survival ( table 2 ) . the overall survival was significantly affected by the figo stage at the time of the initial diagnosis , the ability to obtain complete resection with histologic normal margins at the time of surgery for the recurrent disease , recurrence greater than 12 months from the time of the initial diagnosis , and single tumor recurrence . uterine lms affects 6 out of 1 million women annually [ 35 ] and , although rare , this is a deadly disease with a recurrence rate often greater than 60% [ 5 , 6 , 13 , 23 ] . the series examining similar groups are small ; however , surgery seems to be the treatment of choice for those with first time recurrent disease in selected patients . specifically , those with resectable disease from initial low stage disease and low - grade tumors might benefit the most with operative cytoreduction in this setting [ 4 , 6 , 7 , 13 ] . due to the limited number of patients affected and known benefits of surgical treatment , randomized controlled studies are not feasible . hence , management and prognostic factors have only been determined based on retrospective data [ 4 , 7 , 13 , 14 ] . furthermore , uterine lms is a separate biologic entity with a different prognosis from the other uterine sarcomas and it must be uniquely separated from other primary uterine sarcomas . establishing a histologic confirmation of this diagnosis is paramount for initiating the proper therapy . the rarity of this disease with the small sample size and paucity of published data concerning first time recurrence for uterine leiomyosarcoma limits extensive evaluation . studies exclusively limiting evaluation of patients with histologically confirmed uterine lms where diagnoses such as endometrial stromal sarcoma , adenosarcoma , and carcinosarcoma were excluded from analysis are rare . this is an extremely important variable when analyzing other reports in comparison since these other above entities , although being sarcomas , have completely different biologic behaviors and responses to medical and surgical therapies . confirmation of those with uterine lms as a separate subset is invaluable in establishing prognostic variables for this disease and can not be overemphasized . due to the paucity of published data , prognostic factors as a guide for management options once recurrence has been diagnosed , the reported survival of these patients is as low as 5 months . only a few have reported outcome and prognostic factors of patients with first time recurrence solely for uterine lms [ 22 , 23 ] . outlined are the comparisons between our report and the other similar publications [ 22 , 23 ] evaluating first recurrence for uterine lms ( table 4 ) . for example , the time to first recurrence was longer in this report ; however , the use of perioperative medical therapy was generally similar . this could be related to the fact that in our study we had notably fewer patients with single tumors ( 46% ) and multiple site recurrences ( 54% ) . significant variables associated with prolonged survival included the ability to completely resect the recurrent disease , greater length of time ( > 12 months ) to the first recurrence , and the figo stage at the time of the initial diagnosis . conversely , factors that did not affect survival in our study were the grade of the tumor , type of procedure performed , local versus distant recurrence , and the use of chemotherapy and/or radiation in the perioperative period . reported similar variables that did not affect survival and they included tumor grade , pelvic versus extrapelvic recurrence , thoracic versus nonthoracic surgery , or the use of chemotherapy and/or radiation at the time of the initial diagnosis or in the perioperative period at the time of the first recurrence . the overall survival at 2 and 5 years in the report by giuntoli et al . was consistent without data . overall survival at 2 and 5 years in the report by giuntoli et al . was consistent with our data ; however , the report by leitao et al . had increased survival at 2 years of 70% . our survival at 10 years was lower and could be attributed to more recurrences at multiple sites in our study , which could explain the lower number of patients having complete resection . we did have a longer time span to first recurrence ( 26 months ) versus 15 and 16 months , respectively , for the reports [ 22 , 23 ] . in conclusion , uterine lms is a rare disease with extremely poor prognosis . for selected patients who had time to first recurrence greater than 12 months , resectable disease at recurrence , and early figo stage ( stage 1 ) at the initial diagnosis , Output:	background . uterine leiomyosarcoma ( lms ) is a rare diagnosis , which is seldom cured when it recurs with metastatic disease . we evaluated patients who present with first time recurrence treated surgically to determine prognostic factors associated with long - term survival . methods . over a 16-year period , 41 patients were operated on for recurrent uterine sarcoma . data examined included patient age , date of initial diagnosis , tumor histology , grade at the initial diagnosis , cytopathology changes in tumor activity from the initial diagnosis , residual tumor after all operations , use of adjuvant therapy , dates and sites of all recurrences , and disease status at last followup . results . 24 patients were operated for first recurrence of metastatic uterine lms . complete tumor resection with histologic negative margins was achieved in 16 ( 67% ) patients . overall survival was significantly affected by the figo stage at the time of the initial diagnosis , the ability to obtain complete tumor resection at the time of surgery for first time recurrent disease , single tumor recurrence , and recurrence greater than 12 months from the time of the initial diagnosis . median disease - free survival was 14 months and overall survival was 27 months . conclusion . our findings suggest that stage 1 at the time of initial diagnosis , recurrence greater than 12 months , isolated tumor recurrence , and the ability to remove ability to perform complete tumor resection at the time of the first recurrence can afford improved survival in selected patientsat the time of the first recurrence can afford improved survival in selected patients .
PubmedSumm118836	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: fluorine-18 fluorodeoxyglucose positron emission tomography - computed tomography ( f-18 fdg pet - ct ) has evolved as an imaging modality of choice for staging , restaging , treatment response evaluation and surveillance of various cancers . increased fdg uptake is also noted in various benign conditions . we report a case where f-18 fdg pet - ct scan demonstrated residual disease in an operated case of i m . a 36-year - old male presented with slow growing painless lump in the left thigh . magnetic resonance imaging ( mri ) of the thigh demonstrated a well - defined soft tissue lesion in the left rectus femoris muscle with homogenous low - signal intensity on t1-weighted sequences and markedly high signal intensity on t2-weighted sequences . contrast - enhanced t1-weighted mris showed heterogeneous enhancement throughout the mass [ figure 1 ] . excision of the mass was performed and on histopathological examination the tumor showed composition of spindle and stellate shaped cells that were widely separated by myxoid stroma . the tumor cells were immunohistochemically positive for vimentin and cd34 , but negative for s-100 and desmin . however , the cut margins were not free and the patient was referred 10 weeks later for f-18 fdg pet - ct scan for the assessment of residual disease . increased f-18-fdg uptake was noted in the peripheral rim of a well - circumscribed centrally hypodense soft tissue lesion with thin septation in the left rectus femoris muscle [ figure 2 ] . the maximum standardized uptake value ( suvmax ) of the lesion was 3.2 g / ml . these findings were suggestive of residual i m and the same was confirmed on histopathological examination of the postexcision specimen . magnetic resonance imaging ( mri ) of the thigh demonstrated a well - defined soft tissue lesion in the left rectus femoris muscle with homogenous low signal intensity on t1-weighted sequences ( a ) and markedly high signal intensity on t2-weighted sequences ( b ) . contrast - enhanced mris showed heterogeneous enhancement throughout the mass ( c ) increased fluorodeoxyglucose uptake was noted in the left upper thigh on maximum intensity projected ( a ) , coronal positron emission tomography ( pet ) ( b ) and sagittal pet ( e ) images . this uptake corresponds to the peripheral rim of a well circumscribed centrally hypodense soft tissue lesion with thin septation in the left rectus femoris muscle on correlative coronal and sagittal computed tomography ( ct ) images ( c and f ) and pet - ct images ( d and g ) , respectively most of them appear in the fourth to sixth decades of life with a slight female preponderance . i m 's usually arise from large skeletal muscles , the commonest location being the lower extremities , particularly the thigh ( 51% ) , followed by the gluteal region ( 7% ) . the symptoms depend on the site and size of the mass lesion . although majority of the patients were asymptomatic and diagnosed incidentally , few present with slow growing , painless intramuscular tumor . occasionally , the symptoms of nerve root compression may be noted . i m usually occurs as an isolated lesion , but sometimes it is associated with skeletal fibrous dysplasia , when it is known as mazabraud 's syndrome . in such cases , preoperatively , it is difficult to differentiate i m from other malignant myxoid tumors such as myxoid liposarcoma , low - grade fibromyxoid sarcoma , myxoid malignant fibrous histiocytoma and extra skeletal myxoid chondrosarcoma . on imaging , i m appears as hypoechoic mass on ultrasound , shows low attenuation on ct , low - signal intensity on t1-weighted mris , and markedly high signal intensity on t2-weighted mris . contrast - enhanced imaging ( particularly mris ) more accurately reflects the truly solid ( although usually hypocellular ) consistency of the i m because it shows internal enhancement . several studies have been performed to evaluate the role of f-18 fdg pet - ct scan to differentiate benign and malignant myxoid neoplasms . however , the results were not encouraging . the definite diagnosis of i m can only be made from the histopathological examination after its surgical excision , which is considered to be the treatment of choice . complete resection is associated with excellent prognosis and no local recurrence generally occurs during an average follow - up of 7 years after excision . however , incomplete resection is associated with recurrence and completeness of surgery is the most important determinant of the overall outcome of the disease . i m shows low - grade f-18 fdg uptake with suv values between 1.3 and 2.6 . furthermore , whole body f-18 fdg pet - ct has been reported to be useful to detect fibrosis dysplasia and single or multiple i m 's in mazabraud 's syndrome . however , its role in assessing postoperative residual i m is not described in the literature to the best of our knowledge . this case demonstrates the possible role of f-18 fdg pet - ct scan to detect postoperative residual i m . Output:	intramuscular myxoma ( i m ) is a rare benign neoplasm . in a patient diagnosed with i m of left thigh , we report the utility of a postoperative fluorine-18 fluorodeoxyglucose positron emission tomography - computed tomography scan in assessing the efficacy of surgical excision .
PubmedSumm118837	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: a 9 kb fragment of the mglur6 promoter was used to express yellow fluorescent protein ( yfp ) and the light chain of tetanus toxin ( tent ) selectively in retinal on bcs . in the other ( mglur6-tdtomato ) the 9 kb mglur6 promoter fragment drove expression of the red fluorescent protein tandem dimer tomato ( tdtomato ) . paraformaldehyde ( 4% ) fixed retinal flat mount preparations or vibratome slices were labeled by standard immunohistochemistry procedures . we performed whole - cell patch clamp recordings from rgcs in retinal flat mount preparations to analyze spontaneous excitatory synaptic transmission and used multielectrode array recordings to characterize light responses during white noise presentation from an organic light emitting display ( oled ) . images of fixed tissue were acquired on an olympus fv1000 confocal microscope using a 1.35 na 60 oil objective . time lapse imaging experiments on retinas of mglur6-yfp / tent mice and wildtype littermates were performed in parallel on an olympus fv1000 confocal microscope ( mglur6-yfp / tent ) and either an olympus fv300 confocal or a custom built two photon microscope ( wildtype ) using 1.1 na 60 water objectives . image stacks were analyzed using amira ( mercury computer system inc . ) , imaris ( bitplane ) and software custom written in matlab ( the mathworks ) . retinas were fixed using standard em fixation techniques , cut into pieces and en bloc stained in uranyl acetate . a 9 kb fragment of the mglur6 promoter was used to express yellow fluorescent protein ( yfp ) and the light chain of tetanus toxin ( tent ) selectively in retinal on bcs . in the other ( mglur6-tdtomato ) the 9 kb mglur6 promoter fragment drove expression of the red fluorescent protein tandem dimer tomato ( tdtomato ) . paraformaldehyde ( 4% ) fixed retinal flat mount preparations or vibratome slices were labeled by standard immunohistochemistry procedures . we performed whole - cell patch clamp recordings from rgcs in retinal flat mount preparations to analyze spontaneous excitatory synaptic transmission and used multielectrode array recordings to characterize light responses during white noise presentation from an organic light emitting display ( oled ) . images of fixed tissue were acquired on an olympus fv1000 confocal microscope using a 1.35 na 60 oil objective . time lapse imaging experiments on retinas of mglur6-yfp / tent mice and wildtype littermates were performed in parallel on an olympus fv1000 confocal microscope ( mglur6-yfp / tent ) and either an olympus fv300 confocal or a custom built two photon microscope ( wildtype ) using 1.1 na 60 water objectives . image stacks were analyzed using amira ( mercury computer system inc . ) , imaris ( bitplane ) and software custom written in matlab ( the mathworks ) . retinas were fixed using standard em fixation techniques , cut into pieces and en bloc stained in uranyl acetate . full methods and any associated references are available in the online version of the paper at www.nature.com/nature . Output:	activity is thought to guide the patterning of synaptic connections in the developing nervous system . specifically , differences in the activity of converging inputs are thought to cause the elimination of synapses from less active inputs and increase connectivity with more active inputs1,2 . here we present findings that challenge the generality of this notion and offer a novel view of the role of activity in synapse development . to imbalance neurotransmission from different sets of inputs in vivo , we generated transgenic mice in which on but not off types of bipolar cells ( bcs ) in the retina express tetanus toxin ( tent ) . during development , retinal ganglion cells ( rgcs ) select between on and off bc inputs ( on or off rgcs ) or establish a similar number of synapses with both on separate dendritic arbors ( on - off rgcs ) . in tent retinas , on rgcs correctly selected the silenced on bc inputs over the transmitting off bcs , but were connected with them through fewer synapses at maturity . time - lapse imaging revealed that this was caused by a reduced rate of synapse formation rather than an increase in synapse elimination . similarly , tent - expressing on bc axons generated fewer presynaptic active zones . the remaining active zones often recruited multiple , instead of single , synaptic ribbons . on - off rgcs in tent mice maintained convergence of on and off bcs inputs and had fewer synapses on their on arbor without changes to off arbor synapses . our results reveal an unexpected and remarkably selective role for activity in circuit development in vivo , regulating synapse formation but not elimination , affecting synapse number but not dendritic or axonal patterning , and mediating independently the refinement of connections from parallel ( on and off ) processing streams even where they converge onto the same postsynaptic cell .
PubmedSumm118838	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: carcinoma of the uterine cervix is the most common malignancy that affects women in several parts of the world and causes high mortality ( 1 ) . it is the second most common cancer affecting women worldwide and its occurrence has steadily increased in young women ( 2 ) . it has been documented that approximately 500 000 new cases and 274 000 deaths occur each year due to this disease ( 3 ) . this disease is more prevalent among women of low socioeconomic status and is a major health problem in developing countries . in india , it has become the leading cancer among women with an annual incidence of about 130 000 cases and 7075 000 deaths ( 4 ) . it has been established that human papillomavirus ( hpv ) is an etiologic agent for development of cervical cancer , yet it has been observed that an infection caused by hpv alone is not a sufficient factor for causation of cervical cancer . rather , genetic and environmental factors that act in concordance have been suggested to contribute to the induction of cervical cancer . it is thought that other reasons including changes in tumor suppressor genes , activation of cellular proto - oncogenes , chromosomal alterations or altered expression of several genes too are required for tumorigenesis ( 5 ) . as a result several investigators in recent years have , by conducting small - scale ( individual gene ) and high - throughput studies like microarray expression profiling ( 6 ) , compared normal cervical cells with premalignant and malignant cervical cells . this has resulted in generation of enormous data and revelation of hundreds of genes that are differentially expressed , thus providing researchers important resources to potentially explore the molecular mechanisms and identify cervix - cancer - related genes . despite presence of voluminous biomedical literature in pubmed that provides evidence for variety of genes implicated in cervical cancer and women worldwide increasingly being affected from this malignancy , to our knowledge no resource exists that focuses on cervix cancer . strikingly , a number of databases have been published over the years that collect information on several specialized cancers like human lung cancer database ( 7 ) , prostate gene database ( 8) , oral cancer gene database ( 9 ) and breast cancer gene database ( 10 ) , but none of these databases exists for genes involved in cervix cancer causation , one of the leading cancers that affect women worldwide . therefore , we have collected cervix - cancer - related genes to construct an integrated database termed cervical cancer gene database ( ccdb ) that catalogs the genes known to be involved in cervical carcinogenesis as evidenced from the biomedical literature . to gather and uniformly present the available information on cervix cancer genes , the database integrates heterogeneous data including basic gene and protein information , manually curated literature references to support inclusion of a gene in the database , the biological alteration , gene ontology ( go ) information , homologous sequences in other eukaryotic genomes , interacting partners , microrna ( mirna ) reported to be altered in cervical carcinomas as compared with normal cervix , as well as information and links of several external resources / databases in order to help in retrieval of any other related information . in addition , the database provides search facility for querying the database and an online tool for sequence similarity search . overall , ccdb is a specialized , first of its kind value - added database that will enable the exploration of relevant information for all experimentally determined human cervix - cancer - related genes making it a unique resource in the area of cervix cancer biology . for collection of genes playing role in causation of cervix cancer we have extensively searched pubmed database and collected the relevant literature manually . after we obtained the literature , we read through the full text of each article to identify one or more genes involved in disease process . thereafter , information regarding the type of molecular and genetic events ( such as methylation , gene amplification , mutation , altered expression and polymorphism ) responsible for occurrence of cervical cancer disease as documented in the references was recorded along with the tracking number ( pmid ) . also , we have collected information about the location from which sample was collected by their respective authors to conduct the study . once a non - redundant list of genes was extracted from the literature further information regarding the gene was derived and has been integrated into other tables . overall , ccdb is divided into six tables : ( i ) the gene detail table , which stores information necessary for the conversion between different gene and protein identifiers , using the gene i d as primary key , ( ii ) the homology table , which stores the orthology relationships derived from homologene database ( 11 ) , ( iii ) the reference table ( detailed above ) , ( iv ) the go table , ( v ) the sequence table , which stores mrna , cds and protein location and sequences and ( vi ) 3d protein structure information table ( figure 1 ) . mirnas are a family of small non - coding rna molecules that downregulate the expression of their protein - coding gene targets . the recent studies provide evidences that multiple mirnas have altered expression in various human cancers , including cervical cancer . this provides a good indication that knowledge of differential expression of mirna in cancer may have substantial diagnostic and prognostic value and hence these are considered as an important resource for cancer research . therefore , we selected cervix - cancer - related mirnas with experimental information from the literature and documented information regarding host gene that codes for mirna , its location , the target gene and its potential role . once all the information was gathered we integrated the data in mysql , an object - relational database management system ( rdbms ) , which works at the backend and the web interface , was built in php . currently , we have collected 537 genes that are involved in the different stages of cervical carcinogenesis . the information thus accumulated is expected to be critical for both scientific researchers and clinicians to understand and determine the molecular mechanism that causes cervix cancer . users can query the database by gene name , gene i d or chromosome number , which results in display of gene - centered information in a new page ( figure 2 ) . the main page for each gene provides the following information ( i ) a schematic view of intron / exon structure , ( ii ) general information including the gene name , gene i d , contig , location , omim i d , unigene i d , ensembl i d , hprd i d , ( iii ) link to references that validate the presence of this gene in cervical cancer , ( iv ) link to homologous gene entries , ( v ) link to mrna / cds / protein sequence details and ( vi ) link to other public databases , e.g. hgnc and pharmagkb . clicking on hprd link leads to go information , and homologene i d link provides the details of similar sequences ( mrna and protein i d ) that are present in other eukaryotic genomes along with multiple sequence alignment generated using clustalx ( 12 ) in pdf format . further , to know how a gene is related to cervix cancer , the user can click on the reference link that displays the references used as evidence for establishing relationship of the gene to cervix cancer along with the aberrant biological process responsible for causing cervix cancer . moreover , the mrna / cds / protein link provides information regarding the various isoforms encoded by the gene , their location , length as well as mrna , cds and protein sequences of each isoform . figure 2.schematic workflow of ccdb . also ccdb provides three other ways to view and retrieve all cervix - cancer - related genes . first , a user can query the database for human chromosome number to display the genes present on each chromosome and then browse them individually . second , ccdb also offers a browsing section , which allows the user to access the entire collection of genes ( complete list ) or search the genes by their names that are ordered in the alphabetical mode . finally , the genes have been categorized into biological process whose alteration leads to cervix cancer disease as evident from literature . thus , ccdb provides a gateway through which the biomedical community can easily access the latest information on the genes involved in cervix cancer . further , a customized blast ( 13 ) tool has been made available that searches a user - defined query against the sequences available in the database . it may be useful in characterization of orphan sequences and fishing out of homologous sequences from the database , based on sequence similarity . additionally , an online submission facility has been provided to add gene entries that are associated with cervix cancer ( this option is yet to be functional ) . once the user adds new gene information with specified fields ( the fields with star are mandatory ) , the database would be updated after validation . although over the years a large number of cancer - specific databases ( e.g. human lung cancer database , prostate gene database , oral cancer gene database and breast cancer gene database ) have been published , yet , to date to our knowledge , there is no resource available that provides detailed information about the genes known to be associated with cervix cancer . therefore we have compiled the first ccdb , where manual curation along with information from other resources have been integrated to provide a knowledgebase that will allow researchers and clinicians to get an overview of biology of the genes involved in cervix cancer . we hope that the availability of this database would save time and effort of researchers involved in the field and thus will facilitate the biological discovery process . go terms have been used previously to characterize protein function and to elucidate trends in protein datasets . we too classified all cervix - cancer - related genes according to the molecular function of each protein and the biological process in which it is involved . assignment of 537 genes to various molecular functions revealed that the top five categories represented in the dataset are : transcription factor activity , transcription regulatory activity , cell adhesion molecule activity , receptor activity and dna binding , thereby suggesting importance of these gene products for developmental pathway of cervical cancer cells . also , we observed that the biological processes that are enriched in ccdb are ( i ) cell communication and signal transduction pathway : 26% , ( ii ) regulation of nucleobase , nucleoside , nucleotide and nucleic acid metabolism : 17% and ( iii ) protein metabolism : 12% . this suggests that these biological processes may be involved in transition of cell progression to cancerous state . further homology information is crucial as it reveals how conserved a protein has remained through evolution , and hence the degree to which it can tolerate alteration within the sequence . using the data of 537 genes involved in cervix cancer we find most of the proteins exhibit homology to other eukaryotic genomes except six . although almost all the proteins exhibit homologous sequences in other genomes , majority ( 39% ) are conserved in euteleostomi and only a small fraction are conserved in eukaryotic crown group ( 16% ) , i.e. they are highly conserved across the eukaryotic domain of life . the presence of a large proportion of ccdb genes within euteleostomi group suggests that these genes are present in fish species and have arisen recently on the evolutionary line and thus , it may be possible that these proteins are responsible for distinguished characteristics . also it is a well - established fact that hypermethylation of tumor - suppressor genes has long been associated with various cancers , including cervical cancer . in the present version of ccdb , we present evidence for 69 genes that are hypermethylated in cervical cancer , much more than the pubmeth database ( 14 ) . pubmeth is an annotated and reviewed database of methylation in cancer , which catalogs information for 36 genes involved in various stages of cervical cancer . however , presently our database is not supported by as many literature references as documented in pubmeth . therefore , we feel that our database will complement the existing database in serving scientific community . also , another advantage of this database will be that it allows researchers to make a thorough comparison of genes that are common in most of the cancers as well as detect the ones that are unique and demonstrate aberrant behavior in cervix cancer . for example , comparison of the present set of ccdb genes with two other databases ( human lung cancer database and prostate gene database ) revealed that there are 293 and 35 genes common among these cancers respectively . the current release ( v. 1.0 ) of ccdb contains 537 unique genes that are supported by evidence from unique pubmed records . the data are presented in a systematic way and apart from search facility , several browsing options facilitate fast , efficient and user - friendly retrieval of information . we propose to update this database on a regular basis adding new data from literature as well as other data analysis tools that will help in improving our knowledge about cervix cancer and potentially contribute to the development of novel therapeutic strategies . since not all genes published in literature are yet included in the current release of the database , our foremost objective would be to identify , collect and add those genes . also , another limitation of the present version is that not all the related references for a given gene have been covered . therefore , in the next update we plan to add more literature references for genes in the current version . we also propose to extend search facility and include information about transcription factor binding site . overall , we aim to increase the quality of data and to supply additional database function . in summary , ccdb is a first attempt to provide a comprehensive non - redundant catalog of genes involved in the cervix cancer along with information about the altered biological process and supporting evidence from published literature . it is expected that availability and use of ccdb will reduce the time and effort of scientists and clinicians to survey the literature on genes and their involvement in cervix diseases . it thus provides a unique value - added resource in the field of cervix cancer biology . funding for open access charge : institute of cytology and preventive oncology , indian council of medical research . Output:	the cervical cancer gene database ( ccdb , http://crdd.osdd.net/raghava/ccdb ) is a manually curated catalog of experimentally validated genes that are thought , or are known to be involved in the different stages of cervical carcinogenesis . in spite of the large women population that is presently affected from this malignancy still at present , no database exists that catalogs information on genes associated with cervical cancer . therefore , we have compiled 537 genes in ccdb that are linked with cervical cancer causation processes such as methylation , gene amplification , mutation , polymorphism and change in expression level , as evident from published literature . each record contains details related to gene like architecture ( exon intron structure ) , location , function , sequences ( mrna / cds / protein ) , ontology , interacting partners , homology to other eukaryotic genomes , structure and links to other public databases , thus augmenting ccdb with external data . also , manually curated literature references have been provided to support the inclusion of the gene in the database and establish its association with cervix cancer . in addition , ccdb provides information on microrna altered in cervical cancer as well as search facility for querying , several browse options and an online tool for sequence similarity search , thereby providing researchers with easy access to the latest information on genes involved in cervix cancer .
PubmedSumm118839	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: multiple myeloma ( mm ) is one of the most common hematological malignancies involving the spine . pathological fracture of the vertebral body and neurological deterioration can occur as a form of skeleton related event in patients with mm . under these conditions , surgical intervention or conservative treatment including radiotherapy have been tried for local control . however , there are still debates on which therapeutic approach is optimal7,10,13,17 ) . in particular , spinal cord compression by epidural myeloma with or without pathological fractures is a grave complication and , in this condition , timely optimal treatment is essential . , we present three patients suffering from spinal cord compression caused by an epidural myeloma with different clinical courses and results . by reviewing the related literatures brief descriptions of the presented patients are summarized in ( table 1 ) . a 62-year - old woman with no significant medical background , presented with upper back pain for one month and progressive lower extremity numbness and weakness . she was unable to walk unaided in the last several days and had developed urinary incontinence . a neurological examination revealed bilateral lower extremity weakness with grade iv strength , decreased deep and superficial sensation , a tingling sensation below the umbilicus and increased knee jerk . initial laboratory tests revealed a hemoglobin of 14.0 g / dl , white cells of 8200/mm , erythrocyte sedimentation rate of 120 mm / h , and elevated serum total protein of 10.1 g / dl ( normal range , 6.6 - 8.3 g / dl ) , but she did not have renal or hepatic insufficiency . additional laboratory tests including a bone marrow biopsy revealed chain immunoglobulin g ( igg ) multiple myeloma . on magnetic resonance imaging ( mri ) of the entire spine that was taken to evaluate the neurological condition , an epidural mass was found to compress the spinal cord posteriorly , extending from the c7 to t2 vertebra . the epidural mass was hypointense to the spinal cord on t1-weighted images and hyperintense on t2-weighted images , with moderate contrast enhancement . high - dose steroid therapy ( dexamethasone , 40 mg / day ) and emergent radiotherapy were performed under the diagnosis of mm and spinal cord compression . before this medical treatment , her neurological status was frankel b. mri , checked after 3000 cgy fractioned radiotherapy for the c7-t2 lesion , revealed complete resolution of the epidural mass ( fig . during 6 months of follow - up , the patient did not experience any neurological improvement ( final neurological status , frankel b ) . a 39-year - old woman presented with both shoulder and upper back pain for 1 month . a bone marrow biopsy was performed due to findings of an a / g ratio reversal , anemia , hypercalcemia and azotemia on laboratory tests revealed multiple myeloma . the findings of multiple punched out lesion in the skull and multiple osteolytic lesions over the spine on the radiological examination were matched with mm ( igg , chain ) . computed tomography ( ct ) scans for the upper back pain revealed an epidural mass compressing the spinal cord . high - dose steroid therapy and fractioned radiotherapy ( c7-t2 , 3000 cgy ) were conducted for the spinal cord compression lesion . after the ninth fraction of radiotherapy , she suddenly developed both lower extremity weakness , sensory disturbance below the t4 level and urinary incontinence ( frankel b ) . a follow - up mri revealed sustained compression of the spinal cord by an epidural mass without any additional pathological fractures . a friable bluish gray colored soft tissue mass was found at the epidural space compressing the spinal cord with mild adhesion to the underlying dura . coincident microscopic findings of multiple myeloma with < 10% necrosis rates were observed from the excised mass ( fig . a 62-year - old woman was presented with upper back pain and progressive weakness for one month . on her history , she had undergone posterior spine surgery for a multiple compression fracture 6 months ago . mri showed multiple pathological fracture involving t4 , 7 , and 9 and an epidural mass was compressing the spinal cord at the t4 level . on neurological examination , her lower extremity motor power was over grade iv and she was able to walk unaided ( frankel d ) , even though she complained of lower extremity weakness . high - dose steroid and fractioned radiotherapy were performed . a radiological examination conducted 3 months post - radiotherapy revealed complete resolution of the cord compression and disappearance of the epidural mass ( fig . a 62-year - old woman with no significant medical background , presented with upper back pain for one month and progressive lower extremity numbness and weakness . she was unable to walk unaided in the last several days and had developed urinary incontinence . a neurological examination revealed bilateral lower extremity weakness with grade iv strength , decreased deep and superficial sensation , a tingling sensation below the umbilicus and increased knee jerk . initial laboratory tests revealed a hemoglobin of 14.0 g / dl , white cells of 8200/mm , erythrocyte sedimentation rate of 120 mm / h , and elevated serum total protein of 10.1 g / dl ( normal range , 6.6 - 8.3 g / dl ) , but she did not have renal or hepatic insufficiency . additional laboratory tests including a bone marrow biopsy revealed chain immunoglobulin g ( igg ) multiple myeloma . on magnetic resonance imaging ( mri ) of the entire spine that was taken to evaluate the neurological condition , an epidural mass was found to compress the spinal cord posteriorly , extending from the c7 to t2 vertebra . the epidural mass was hypointense to the spinal cord on t1-weighted images and hyperintense on t2-weighted images , with moderate contrast enhancement . high - dose steroid therapy ( dexamethasone , 40 mg / day ) and emergent radiotherapy were performed under the diagnosis of mm and spinal cord compression . before this medical treatment , her neurological status was frankel b. mri , checked after 3000 cgy fractioned radiotherapy for the c7-t2 lesion , revealed complete resolution of the epidural mass ( fig . during 6 months of follow - up , the patient did not experience any neurological improvement ( final neurological status , frankel b ) . a 39-year - old woman presented with both shoulder and upper back pain for 1 month . a bone marrow biopsy was performed due to findings of an a / g ratio reversal , anemia , hypercalcemia and azotemia on laboratory tests revealed multiple myeloma . the findings of multiple punched out lesion in the skull and multiple osteolytic lesions over the spine on the radiological examination were matched with mm ( igg , chain ) . computed tomography ( ct ) scans for the upper back pain revealed an epidural mass compressing the spinal cord . high - dose steroid therapy and fractioned radiotherapy ( c7-t2 , 3000 cgy ) were conducted for the spinal cord compression lesion . after the ninth fraction of radiotherapy , she suddenly developed both lower extremity weakness , sensory disturbance below the t4 level and urinary incontinence ( frankel b ) . a follow - up mri revealed sustained compression of the spinal cord by an epidural mass without any additional pathological fractures . a friable bluish gray colored soft tissue mass was found at the epidural space compressing the spinal cord with mild adhesion to the underlying dura . coincident microscopic findings of multiple myeloma with < 10% necrosis rates were observed from the excised mass ( fig . a 62-year - old woman was presented with upper back pain and progressive weakness for one month . on her history , she had undergone posterior spine surgery for a multiple compression fracture 6 months ago . mri showed multiple pathological fracture involving t4 , 7 , and 9 and an epidural mass was compressing the spinal cord at the t4 level . on neurological examination , her lower extremity motor power was over grade iv and she was able to walk unaided ( frankel d ) , even though she complained of lower extremity weakness . high - dose steroid and fractioned radiotherapy were performed . a radiological examination conducted 3 months post - radiotherapy revealed complete resolution of the cord compression and disappearance of the epidural mass ( fig . however , as mm is a bone - marrow based neoplastic proliferation of plasma cells that secrete a monoclonal immunoglobulin , skeleton related events are not uncommon . among these skeleton events , the spine is one of the most commonly involved sites and pathological fractures of the spinal column are the most common spinal involvement of mm . spinal cord compression is reported to develop in 11 - 24% of patients with mm17 ) . most cord - compression lesions occur due to a pathological fracture of the involved vertebral body or extension of a vertebral body myeloma lesion . however , an epidural myeloma could elicit spinal cord compression as a rare form of extraosseous myeloma . although the exact incidence of spinal cord compression by epidural myeloma has not been reported , extraosseous involvement of mm is an uncommon condition and is found in < 5% of patients with mm5 ) . the sites of predilection for an extraosseous myeloma are the submucosal tissue of the upper respiratory tract , the gastrointestinal tract , pleura and the central nervous system3 ) . among them , spinal cord compression from an epidural myeloma without combined pathological fractures of the vertebral body is a rare condition and has mainly been reported as a case presentations in the literature1,8,10 ) . radiographs in patients with an epidural myeloma are usually normal and in some cases , multiple compression fractures and osteopenic appearance of the vertebral body could suggest mm . mri is the best diagnostic modality for detecting spinal cord compression , epidural masses and marrow involvement of mm . all of our patients were previously diagnosed by a hematological specialist and referred to our department for an evaluation of the spine lesions . although the third case showed an accompanying pathological fracture of t4 , the spinal cord compression developed not by the pathological fracture but by the posteriorly located epidural mass . this epidural lesion should be distinguished from several other neoplastic or inflammatory conditions , such as tuberculous infection particularly in endemic areas , metastatic lesion , lymphoma and meningioma . although other clinical data including laboratory results could be useful to differentiate , a histopathological diagnosis might be required to confirm the diagnosis . extraosseous epidural myeloma is believed to originate from lymphoid tissue in the epidural or paraspinal lymph node10 ) . however , a signal change in the adjacent spinous process was observed in all of our cases . a directly extension or connection to this posterior marrow lesion could not be ruled out . in general , extraosseous myeloma involvement at diagnosis or during the course of disease is considered a poor prognosis3 ) . failure of neurological recovery has been observed in most reported cases with various treatment modalities as our cases showed2,9,11 ) . because of the limited size of most reports and the differences in the treatment provided , no clear guidelines have been established for spinal cord compression caused by a myeloma . some authors recommend radiotherapy combined with high - dose steroid therapy as the first choice of treatment because mm is highly sensitive to radiotherapy6,12 ) . in one report , radiotherapy alone was tried for 63 patients with mm . the authors reported that 76% of the patients experienced an improvement in motor function , 2% deteriorated and local control was achieved in 98% in 1 year14 ) . in contrast , surgical decompression was attempted in several reports and early surgical decompression followed by radiotherapy or chemotherapy was recommended4,8,10,15 ) . however , most authors agreed that timely intervention is critical for spinal cord compression by a myeloma . as our cases and other reported cases have shown , neurological recovery beyond the critical point is extremely rare regardless of the radiotherapy or surgery attempted . although further research to define the optimal treatment for this condition is mandatory , close observation of the neurological status and patient and medical staff awareness of neurological deterioration are also important to prevent neurological deficits and obtain favorable results . moreover , the involved level by the epidural myeloma is one of the important factors to be considered . if the involved level is the cervical or thoracic level , likely these presented cases , more attentions should be paid to monitor the neurologic status . surgical intervention prior to non - surgical treatment should be considered in the cases presented with any deterioration of the neurologic status . although we could not reach a firm conclusion with theses cases of the limited numbers , we present an algorithm to help the clinical decision - making process and define the role for surgery in the spinal involvement of myeloma from the perspective of spine surgeon ( fig . the mechanical status of the spine and neurological status are two important factors to be assessed . as most surgeons recognize , these local factors are one of the many components used to determine management of the patient with spinal lesions caused by a myeloma . it is our obligation as spine surgeons to provide patients with the most reliable and optimal treatment and to alleviate pain and maintain their quality of life . optimal therapeutic strategy for epidural myeloma and spinal cord compression as one of devastating complications of multiple myeloma is still under debate . by review of cases with different clinical courses and related literatures close evaluation for mechanical stability and neurologic status , and multidiscipline approach are important factors leading successful results for this systemic disease . Output:	multiple myeloma , a multicentric hematological malignancy , is the most common primary tumor of the spine . as epidural myeloma causing spinal cord compression is a rare condition , its therapeutic approach and clinical results have been reported to be diverse , and no clear guidelines for therapeutic decision have been established . three patients presented with progressive paraplegia and sensory disturbance . image and serological studies revealed multiple myeloma and spinal cord compression caused by epidural myeloma . emergency radiotherapy and steroid therapy were performed in all three cases . however , their clinical courses and results were distinctly different . following review of our cases and the related literature , we suggest a systematic therapeutic approach for these patients to achieve better clinical results .
PubmedSumm118840	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: while the disease occurs occasionally in younger age groups , it predominates at retirement age . the incidence of the disease increases with each passing year . in the czech republic , its prevalence is highest in the oldest age groups , ( over 80 years ) in excess of ten occurrences . every 25th person suffering from dementia has not yet reached 60 years of age , whereas every eighth person is older than 80 years.1 in the group of people up to 65 years , every 866th person suffers from dementia . on the contrary , every 13th person in the age group over 65 years suffers from it . in the case of the oldest age category , over 80 years of age , every fifth person suffers from dementia . in the age group over 90 years , every second person suffers from it.1 the number of people suffering from dementia in prague is almost 19,000 , which is logical as the capital city has the oldest population structure.1 there are nearly 17,000 people with dementia in the south moravian region , whereas there are 16,000 and 15,800 people in the central bohemian region and moravian - silesian region , respectively . the lowest number of people with dementia ( 3,600 ) live in the karlovy vary region , which is also the region with the youngest population structure . it has always been difficult to determine the number of people suffering from alzheimer s disease or other types of dementia in the czech republic . to learn more about who takes care of the needy , and what services are provided to them , is even more complicated . with the exception of the selected data from the institute of health information and statistics ( ihis cr),2 research institute for labor and social affairs,3 and interim reports of the relevant ministries , there are almost no relevant resources that could be used , although service providers are required to publish huge amounts of data . in the health statistics ihis cr , where the data is most available , the selected indicators are published complexly in a 4-year period . moreover , learning more about the oldest age groups ( over 80 years ) is also impossible because only aggregated data are presented.4 nevertheless , the importance of this age category will grow and that might be a motivation for more appropriate and more often data provision . even though there were attempts to unify the care for people with dementia , it still takes place in separated and unconnected sectors . part of the care is provided through the health care system and some through social services . despite repeated efforts , the specific interface of these systems in the form of long - term social and health care is still unanchored . a substantial part of the services is also provided on an informal basis by family members and other carers at home . we know almost nothing about this area . among these , commercial interest in the context of the gray economy is followed in a smaller number of cases . the methods used in this paper included time series analyses , methods of direct questioning , interviews with experts , and analyses of medical documentation . the data used were nonpublic , which were provided by the scientific cooperation of the faculty of informatics and management , university of hradec krlov , and the hradec krlov branch of the general health insurance company of the czech republic . data were monitored in time series from 2010 to 2014 for the entire czech republic . the general health insurance company of the czech republic is the largest insurance company in the czech republic . approximately 58.3% of all the insured people in the czech republic are clients of this company5 ( data relevant to december 31 , 2013 ) . the paper also used data from large university hospitals , which are managed by the czech republic ministry of health , because these hospitals deal with the issue of alzheimer s disease . furthermore , the paper is based on the data present in the comprehensive report of the care for patients treated for dementia in out - patient and in - patient facilities of the czech republic in 20082012 , published by the institute of health information and statistics of the czech republic ( ihis cr ) in prague on december 31 , 2013.2 the authors also obtained data from their own investigation in the form of a guided interview with an expert , in this case with the head of the department of neurology , which took place in the university hospital in hradec krlov from september to december 2014 . the results are related to diagnoses according to the international classification of diseases ( icd ) , ie , g30 alzheimer s disease , g30.0 alzheimer s disease with early onset , g30.1 alzheimer s disease with late onset , g30.8 other alzheimer s disease , and g30.9 alzheimer s disease unspecified.5 except from the later , the diagnosis of f00 is dementia in alzheimer s disease , and diagnoses of f01f03 are other dementias . these two approaches involve totally different practices and consequently different costs and demands of other resources . in 2012 , 15,352 patients with the diagnosis of f00 ( dementia in alzheimer s disease ) and 21,279 patients with the diagnoses of f01f03 ( other dementias ) were treated in outpatients facilities in the czech republic.2 based on the investigation of the research team in the university hospital in hradec krlov , data were obtained through a guided interview with the head of the department of neurology . moreover , the outcomes were supported by the real data obtained from the department of neurology.6 hort et al7 provided recommendations for clinical diagnoses ; blood tests ; neuropsychology , neuroimaging , electroencephalography , and cerebrospinal fluid ( csf ) analysis ; genetic testing ; disclosure of diagnosis ; treatment of alzheimer s disease ; behavioral and psychological symptoms in dementia ; legal issues ; and counseling and support for caregivers . this research team revised all the available data and compared them with the european federation of neurological societies ( efns ) guideline . further data are illustrated in table 1 , which exemplify good practice from the department of neurology in the university hospital in hradec krlov , czech republic . points represent the assessment of particular medical examination or treatment according to the act no 324/2014 coll.8 test for tau protein may be used as a supplemental test to help with the establishment of a diagnosis of alzheimer s disease . moreover , its results can distinguish between alzheimer s disease and other forms of dementia . their use is limited to those suspected of dementia , and testing is typically performed after other causes of a person s symptoms have been ruled out . visits to a neurologist may be two times or three four times per year according to the patient s condition . it includes two visits to a neurologist per year , blood tests twice per year , sampling of csf once per year , h - tau test once per year , and the cost of medication.6 a total of 2,627.52 points were required and an amount of 97 was spent ( point value for 2014 was 0.037 ) . this needs to include the cost of drugs , which is 1,745 per year.6 the average annual cost of outpatient treatment per patient was 1,842 per year . the situation of the patients examined with dg g30 , g30.0 , and g30.1 in the university hospital of hradec krlov is described in the table 2 . a total of 8,669 cases with primary diagnosis f01 , f03 , and g30 ( dementia ) were hospitalized in psychiatric inpatient facilities . regarding alzheimer s disease , the most commonly hospitalized cases were with the diagnosis g30.1 , alzheimer s disease with late onset ( more than 38% , 1,468 cases ) . between 2008 and 2012 , the total number of hospitalizations of patients with dementia increased by almost a fifth ( from 7,363 to 8,669 ) . the largest increase was for alzheimer s disease ( by almost 44% , ie , 1,170 hospitalizations).2 the number of hospitalizations for alzheimer s disease with late onset ( dg g30.1 ) increased by 37% ( ie , 393 ) , and it increased by 29% ( from 765 to 990 hospitalizations ) for alzheimer s disease unspecified ( dg g30.9 ) . the number of hospitalizations of patients with alzheimer s disease with early onset ( dg g30.0 ) increased only minimally in the reporting period.2 the longest treatment time on average in the reporting period was reported for alzheimer s disease ( 90 days ) , including alzheimer s disease with late onset with more than 112 days and alzheimer s disease with early onset with 97 days.2 in 2012 , a total of 8,669 patients with dementia , ie , with basic diagnosis of f01 , f03 and g30 , were hospitalized in inpatient care facilities . the proportion of hospitalizations of patients with diagnosis of f01 , vascular dementia , was 36% ( 3,129 hospitalizations ) and diagnosis of g30 , alzheimer s disease , was 44% ( 3,815 hospitalizations ) ; one - fifth of the hospitalizations was linked with the diagnosis of f03 , unspecified dementia ( 1,725 hospitalizations).2,9 table 3 describes costs for inpatient care from 2010 to 2014 in the czech republic . table 4 illustrates the overall number of patients with a particular diagnosis and also the cost required for treatment . it is obvious that if the disease is diagnosed earlier ( g30.0 ) , the cost is nearly two times lower than that in the later stage ( g30.1 ) . first , the public health institutions can use this information for the purpose of prevention support and also for motivating endangered groups of people to visit doctors regularly . moreover , the government might be interested in these outcomes and allocate financial resources more appropriately . health care is provided to people with dementia in the form of outpatient and inpatient care . in 2012 , approximately 37,000 patients were treated in psychiatric outpatient facilities ; other care ( not covered by statistics ) was provided in neurological and geriatric clinics . in the case of inpatient care , over 8,500 hospitalizations of people with dementia were recorded , and the average length of treatment was 78 days . the number of hospitalizations of people with dementia slightly increased in the last 5 monitored years by a few percent , in line with the declining average length of treatment . in case of hospitalized patients , the number of hospitalizations is monitored as a patient may be hospitalized more than once during the reporting period . therefore , the number of hospitalized people and the number of hospitalizations vary . two - thirds ( 65% ) of hospitalized patients in outpatient care are women ; in inpatient care it is 64% . when standardizing the data with the number of people of the given sex in these age groups , the differences among the sexes are not significant.9 standardized data indicate that approximately a quarter ( 26% ) of people with dementia use outpatient health care and less than 6% use inpatient care . the investigation showed that the underpinning of patients with alzheimer s disease at early onset is advantageous from an economic perspective because the cost of outpatient care is much lower compared with inpatient care . furthermore , after discharge from hospital , the patient is usually transported to a facility for follow - up care , eg , departments for long - term patients . family care is usually impossible due to high demands on provided services.10 in the regions of the czech republic , there are fundamental differences that deserve a more detailed investigation . the amount of care needed for patients with dementia is lowest in the liberec region and south bohemian region , and highest in the moravian - silesian region . the amount of people with dementia who are provided with health services differ significantly among regions . in the case of inpatient care the amounts are twice as high , whereas in the case of outpatient care these are sometimes three times greater . in the regions , it is not possible to trace important context and relationships among various types of services . therefore , it can not be stated that one form of service is offset by another.11 the conducted research and the performed analysis are linked with a particular extent of inaccuracy , because of the lack of the public and nonpublic data . this fact should be taken into consideration , which might be a challenge for further research . in 2012 , 15,352 patients with the diagnosis of f00 ( dementia in alzheimer s disease ) and 21,279 patients with the diagnoses of f01f03 ( other dementias ) were treated in outpatients facilities in the czech republic.2 based on the investigation of the research team in the university hospital in hradec krlov , data were obtained through a guided interview with the head of the department of neurology . moreover , the outcomes were supported by the real data obtained from the department of neurology.6 hort et al7 provided recommendations for clinical diagnoses ; blood tests ; neuropsychology , neuroimaging , electroencephalography , and cerebrospinal fluid ( csf ) analysis ; genetic testing ; disclosure of diagnosis ; treatment of alzheimer s disease ; behavioral and psychological symptoms in dementia ; legal issues ; and counseling and support for caregivers . this research team revised all the available data and compared them with the european federation of neurological societies ( efns ) guideline . further data are illustrated in table 1 , which exemplify good practice from the department of neurology in the university hospital in hradec krlov , czech republic . points represent the assessment of particular medical examination or treatment according to the act no 324/2014 coll.8 test for tau protein may be used as a supplemental test to help with the establishment of a diagnosis of alzheimer s disease . moreover , its results can distinguish between alzheimer s disease and other forms of dementia . their use is limited to those suspected of dementia , and testing is typically performed after other causes of a person s symptoms have been ruled out . visits to a neurologist may be two times or three four times per year according to the patient s condition . for the calculation of costs , it includes two visits to a neurologist per year , blood tests twice per year , sampling of csf once per year , h - tau test once per year , and the cost of medication.6 a total of 2,627.52 points were required and an amount of 97 was spent ( point value for 2014 was 0.037 ) . this needs to include the cost of drugs , which is 1,745 per year.6 the average annual cost of outpatient treatment per patient was 1,842 per year . the situation of the patients examined with dg g30 , g30.0 , and g30.1 in the university hospital of hradec krlov is described in the table 2 . a total of 8,669 cases with primary diagnosis f01 , f03 , and g30 ( dementia ) were hospitalized in psychiatric inpatient facilities . regarding alzheimer s disease , the most commonly hospitalized cases were with the diagnosis g30.1 , alzheimer s disease with late onset ( more than 38% , 1,468 cases ) . between 2008 and 2012 , the total number of hospitalizations of patients with dementia increased by almost a fifth ( from 7,363 to 8,669 ) . the largest increase was for alzheimer s disease ( by almost 44% , ie , 1,170 hospitalizations).2 the number of hospitalizations for alzheimer s disease with late onset ( dg g30.1 ) increased by 37% ( ie , 393 ) , and it increased by 29% ( from 765 to 990 hospitalizations ) for alzheimer s disease unspecified ( dg g30.9 ) . the number of hospitalizations of patients with alzheimer s disease with early onset ( dg g30.0 ) increased only minimally in the reporting period.2 the longest treatment time on average in the reporting period was reported for alzheimer s disease ( 90 days ) , including alzheimer s disease with late onset with more than 112 days and alzheimer s disease with early onset with 97 days.2 in 2012 , a total of 8,669 patients with dementia , ie , with basic diagnosis of f01 , f03 and g30 , were hospitalized in inpatient care facilities . the proportion of hospitalizations of patients with diagnosis of f01 , vascular dementia , was 36% ( 3,129 hospitalizations ) and diagnosis of g30 , alzheimer s disease , was 44% ( 3,815 hospitalizations ) ; one - fifth of the hospitalizations was linked with the diagnosis of f03 , unspecified dementia ( 1,725 hospitalizations).2,9 table 3 describes costs for inpatient care from 2010 to 2014 in the czech republic . table 4 illustrates the overall number of patients with a particular diagnosis and also the cost required for treatment . it is obvious that if the disease is diagnosed earlier ( g30.0 ) , the cost is nearly two times lower than that in the later stage ( g30.1 ) . first , the public health institutions can use this information for the purpose of prevention support and also for motivating endangered groups of people to visit doctors regularly . moreover , the government might be interested in these outcomes and allocate financial resources more appropriately . health care is provided to people with dementia in the form of outpatient and inpatient care . in 2012 , approximately 37,000 patients were treated in psychiatric outpatient facilities ; other care ( not covered by statistics ) was provided in neurological and geriatric clinics . in the case of inpatient care , over 8,500 hospitalizations of people with dementia were recorded , and the average length of treatment was 78 days . the number of hospitalizations of people with dementia slightly increased in the last 5 monitored years by a few percent , in line with the declining average length of treatment . in case of hospitalized patients , the number of hospitalizations is monitored as a patient may be hospitalized more than once during the reporting period . therefore , the number of hospitalized people and the number of hospitalizations vary . two - thirds ( 65% ) of hospitalized patients in outpatient care are women ; in inpatient care it is 64% . when standardizing the data with the number of people of the given sex in these age groups , the differences among the sexes are not significant.9 standardized data indicate that approximately a quarter ( 26% ) of people with dementia use outpatient health care and less than 6% use inpatient care . the investigation showed that the underpinning of patients with alzheimer s disease at early onset is advantageous from an economic perspective because the cost of outpatient care is much lower compared with inpatient care . furthermore , after discharge from hospital , the patient is usually transported to a facility for follow - up care , eg , departments for long - term patients . family care is usually impossible due to high demands on provided services.10 in the regions of the czech republic , there are fundamental differences that deserve a more detailed investigation . the amount of care needed for patients with dementia is lowest in the liberec region and south bohemian region , and highest in the moravian - silesian region . the amount of people with dementia who are provided with health services differ significantly among regions . in the case of inpatient care the amounts are twice as high , whereas in the case of outpatient care these are sometimes three times greater . in the regions , it is not possible to trace important context and relationships among various types of services . therefore , it can not be stated that one form of service is offset by another.11 the conducted research and the performed analysis are linked with a particular extent of inaccuracy , because of the lack of the public and nonpublic data . this fact should be taken into consideration , which might be a challenge for further research . the international comparisons of the volume of care provided should be approached with great caution . these comparisons are based solely on the results from various expert estimations and are not usually supported by hard data . yet , they still illustrate an overall view of our ability to take care of people with dementia . according to the experts , the care in the czech republic significantly lags behind the rest of developed europe.1214 while services are provided to 26% of people with dementia in germany and 50% in france , the experts estimate that services are provided to only 10% of the population in the czech republic . if we were to offer a similar volume of services in the czech republic , to the same extent as the average in europe , we would have to triple the existing capacities.9,15 hort et al7 and wimo et al1 have provided a lot of useful recommendations , linked especially with good practices . they have emphasized the assessment , interpretation , and treatment of patients symptoms , disabilities , and specific needs . even more complicated comparison with other european union states is within the social care of patients with alzheimer s disease.1618 unlike health care in social services , there is no regularly published information that would cover the issue of dementia . publicly available information in the registers of social service providers does not help in identifying providers aimed at people with dementia . moreover , the volume of care provided is certainly not sufficient . in the search , it is possible to choose the type of social service provided according to the target group of clients . the target group is closest to the category of people with chronic intellectual illness and , to some extent , to the category of older people . the latter mentioned categories are covered mostly in terms of social services , mainly represented by daycare centers and special homes . Output:	this paper deals with the analysis of the costs , applied , for example , when treating specific diseases an important aid in prioritizing the process of resource allocation . in our review , the specific disease is dementia caused by alzheimer s disease . this paper aims to provide more information on the partial costs per patient that are calculated according to the aggregated data from publicly available sources as well as from the results of authors own investigation . the university hospital in hradec krlov and the general health insurance company of the czech republic participated in this research . the elementary research objective was to compare the costs per patient diagnosed early onset , to those of the patient diagnosed later . the czech republic lacks information regarding dementia . therefore , these issues require attention . the methods used in this paper included time series analyses , methods of direct questioning , interviews with experts , and analyses of medical documentation . these methods were combined to exploit their particular advantages and to ensure the issues discussed , were covered . the investigation showed that the underpinning of patients with alzheimer s disease at early onset is advantageous from an economic perspective , because the cost of outpatient care is much lower compared with that of inpatient care . the international comparisons of the volume of care provided should be approached with great caution . these are based solely on the facts of various expert estimates and are not usually supported by hard data . yet , they still illustrate the overall view of our ability to take care of people with dementia . according to experts , care in the czech republic significantly lags behind the rest of developed europe . while services are provided to 26% of people with dementia in germany and 50% in france , the experts estimate that services are provided to only 10% of the population in the czech republic . if we were to offer a similar volume of services in the czech republic , to the same extent as the average in europe , we would have to triple the existing capacities .
PubmedSumm118841	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: food allergies such as tree nut allergies are potentially fatal group of immune - mediated disorders . recent studies demonstrate that both the prevalence and severity of food allergies are escalating for reasons that are not well understood at present [ 1 , 2 ] . tree nut allergies , along with peanut allergy , are the leading causes of food - induced systemic anaphylaxis in usa and european countries . furthermore , once individuals are sensitized , there is a very low potential for outgrowing tree nut allergies [ 4 , 5 ] . consequently , they are considered not only serious but also persistent health problems for rest of the life of sensitized subjects [ 4 , 5 ] . the specific identity of t- and b - cell subsets that expand during the early stages of establishment of life - threatening nut allergies is largely unknown at present . notably , most of the current knowledge about early expansion and establishment of immune memory cells comes from studies of infectious diseases [ 612 ] . knowledge about identity of such immune cells is urgently needed for potential therapeutic targeting in nut allergies . we have previously reported an adjuvant - free mouse model of tree nut allergy using hazelnut as a model tree nut . this model employs a protocol combining transdermal sensitization followed by oral allergen challenge to elicit systemic anaphylaxis [ 1315 ] . furthermore , hazelnut allergy , once established , remains persistent even when the allergen is withdrawn for at least eight months in this model ; and persistence of clinical sensitivity is associated with robust memory t - cell and memory b - cell responses . since this model does not use an external adjuvant , it offers a unique opportunity to determine the phenotype of t- and b - cell subsets that expand during the early stage establishment of nut allergy . here we report the identification of the phenotype of t- and b - cell subsets that expand in the central and peripheral lymphoid organs during the establishment of nut allergy in this mouse . hazelnut protein extract ( greer labs , lenoir , nc , usa ) : protein content of these three protein extracts was measured by lowry 's method . normal saline was prepared in our lab ( 0.85% w / v nacl solution ) : streptavidin alkaline phosphatase ( jackson immunoresearch , west grove , pa , usa ) . the following fluorochrome - conjugated monoclonal antibodies were purchased from bd biosciences ( san diego , ca , usa ) : cd3e ( clone 145 - 2c11)-percp - cy5.5 , cd4(clone gk1.5)-apc - h7 , cd8alpha(clone 53 - 6.7)-fitc , cd80(16 - 10a1)-fitc , and cd73(ty/23)-pe , while cd44(im7)-pe , cd62l(mel-14)-apc , and b220(ra3 - 6b2)-alexafluor700 were purchased from ebiosciences ( san diego , ca , usa ) . all mice were purchased from jackson laboratories ( bar harbor , me , usa ) . transdermal sensitization followed by oral allergen challenge protocols was performed using the method described previously [ 17 , 18 ] . sensitization was determined by measuring hazelnut - specific ige antibody levels in the plasma using an elisa - based method as described . systemic anaphylaxis upon oral allergen challenge was quantified by rectal thermometry before and at 30 minutes after oral challenge using a digital temperature probe ( thermalert th-5 , physitemp ; nj , usa ; instrument specifications : resolution : 0.1c ; accuracy 0.1c 1 digit ; operating range : 2545c ) . animals were euthanized 1 hr after oral challenge and used for tissue collection . following euthanasia after 1 hour after oral challenge and collection of hypothermia data , bone marrow , spleen , and mesenteric lymph nodes cells were blocked with antimouse cd16/32 ( 2.4g2 prepared in house ) on ice for 10 minutes . subsequently , cells were stained with either a memory t - cell master mix ( cd3 , cd4 , cd8 , cd44 , and cd62l ) or memory b - cell master mix ( b220 , cd80 , cd73 , cd44 , and cd62l ) of monoclonal antibody - fluorochrome conjugates . each monoclonal antibody - fluorochrome conjugate was used at concentrations recommended by the manufacturer or previous antibody titration . cells were incubated with the master mix for 30 minutes on ice in the dark , washed twice with facs buffer , and run on a bd facs canto ii flow cytometer . postacquisition flow cytometry analysis was performed using flowjo software ( tree star , inc . , live cells were gated based on forward scatter and side scatter for both t- and b - lymphocyte samples . t cells were gated as cd3 + on a histogram , cd4 + or cd8 + based on a dot plot , and subsequently a quadrant was drawn to separate cd44 and cd62l+ for each t - cell subset . central memory cd4 and cd8 t cells were defined as cd44/cd62l [ 9 , 19 ] . for b - cell analysis , histogram of b220 was drawn out of live cells , and a quadrant gate was used to distinguish cd62l+ and cd80 + cells . increased expression of cd80 , cd62l and cd73 is indicative of memory b - cell phenotype , and expression of cd73 may indicate isotype switched b cells [ 20 , 21 ] . anova and student 's unpaired tests with welch correction were used to evaluate significance using a software program ( graphpad software , san diego , ca , usa ) . groups of mice were rendered hazelnut allergic using the transdermal sensitization followed by oral elicitation of systemic anaphylaxis to hazelnut that we have described before . the induction of hazelnut - specific ige antibody response upon transdermal exposure is shown ( figure 1(a ) ) . systemic anaphylaxis to oral allergen challenge was confirmed by hypothermia responses ( figure 1(b ) ) . the gating strategy we used , the phenotype of expanding t- and b - cell subsets , in the central and peripheral lymphoid organs is shown in figures 2(a ) and 2(b ) . we examined the subsets of cd4 cells for nave versus memory phenotype using high cd62l expression as a marker of nave cells and low cd62l expression as a marker of memory phenotype . as evident , there was consistent expansion of cd4 + cd62l t cells in bone marrow and spleen ( figures 3(a)3(c ) ) . although there was a similar trend in the mln , it was not statistically significant . we also examined the subsets of cd4 cells for nave versus memory phenotype using high cd44 expression as a marker of memory cells and low cd44 expression as a marker of naive phenotype . as evident , there was a modest increase in the number of cd4 + cd44 + t cells in bone marrow and spleen , but this was not statistically significant ( table 1 ) . then we examined the b cells for nave versus memory phenotype using antibodies to cd80 and cd62l as markers . as evident , there was a modest increase in the proportion of cd80 + b cells in the bm , spleen , and mln . a similar trend was noticed for cd62l b cells in bm and spleen but not in mln ( table 2 ) . we surprisingly found a significant reduction in cd73 expressing cells among b cells with both cd80 + cd62l+ and cd80 + cd62l phenotypes in the mesenteric lymph nodes but in bone marrow or the spleen ( figures 4(a)4(c ) ) . this study was undertaken to identify the phenotype of t- and b - cell subsets that expand during the early stages of establishment of hazelnut allergy in an adjuvant - free mouse model that we have described and characterized before [ 1315 , 22 ] . we studied the immune cell expansion in the bone marrow as a central lymphoid organ , spleen as a systemic peripheral lymphoid organ , and the mesenteric lymph node as representative draining lymphoid organ of the gut . there are three novel and important findings from this study : ( i ) we report a significant expansion of cd4 + cd62l t cells in both the bm and the periphery ; ( ii ) an increase in cd80 + and cd62l b cells in bm and the periphery ; ( iii ) a significant downregulation of cd73 expression on a subset of b cells particularly in the mln . we have previously reported that hazelnut allergy once established in model remains persistent for up to 8 months despite withdrawing allergen exposure . however , the specific phenotype of immune subsets that expand at early stages of the disease establishment in the allergic mice was unknown . as a first necessary step towards the long - term goal of identifying the phenotype of persistent t- and b - cell subsets in this model , here we characterized the phenotype of immune cells that expand early on in this model . we are not aware of previous studies examining this in hazelnut allergy or other models of nut food allergy . it has long been held that memory b cells that expand during immune responses during the early stages reside in the bm and memory t cells reside in the lymph nodes [ 2325 ] . however , recent studies clearly demonstrate that nearly 80% of antigen - specific memory t cells reside in the bm in mice upon infection . our data demonstrate for the first time that hazelnut causes significant expansion of cd4 + cd62l t cells in bm as well as in the periphery . in addition there was a modest elevation of such b cells in bm or the spleen that was not statistically significant . one previous study examined memory t - cell phenotype in a mouse model of airways allergy / asthma . they reported expansion of cd62l memory t cells in the lungs of mice with chronic asthma . it is noteworthy that our data using an adjuvant - free mouse model also demonstrates that cd4 + cd62l t cells are induced in both the spleen and bone marrow in response to hazelnut exposure . clearly , more studies are needed to test whether they are long - lasting memory cells and to determine whether long - term persistence of hazelnut allergy in this model is associated with long - lived such subsets in bone marrow or spleen or both . the surface marker , cd73 , is a glycosyl - phosphatidylinositol- ( gpi-)anchored signaling molecule expressed on both t and b cells [ 20 , 27 ] . other studies have identified cd73 as an important marker of b - cell memory subsets . because of this significance , we examined cd73 and found that a significant proportion of cd80 + b cells downregulates cd73 expression in allergic mice . this suggests that this unusual subset of cells might represent a subset of quiescent b cells that we hypothesize as a potential subset of memory b cells . based on previous reports in the literature , one can use cd62l as a marker to distinguish nave versus memory t cells and cd80 , cd62l , and cd73 as markers of memory b cell subset phenotype . we , however , acknowledge the fact that memory cells are known to be and expected to be heterogeneous , and choosing only a few selected markers is a limitation of our study . also cell analyses were done in mice after they were orally challenged with the allergen to induce shock . therefore , shock - induced redistribution of cells ( if at all occurred in this short time of 1 hour , which is very unlikely ) also possibly contributed to the observations in this study . these data demonstrate for the first time that during the early stages of establishment of hazelnut allergy there is ( i ) expansion of cd4 + cd62l t cell subset in both the bm and the periphery , ( ii ) expansion of cd80 + and cd62l b - cell subset in bm and the periphery , and ( iii ) a significant downregulation of cd73 on a subset of b cells particularly in mln . Output:	nut allergies are potentially fatal and rarely outgrown for reasons that are not well understood . phenotype of t- and b - cell subsets that expand during the early stages of nut allergy is largely unknown . here we studied this problem using a novel mouse model of nut allergy . mice were rendered hazelnut allergic by a transdermal sensitization / oral elicitation protocol . using flow cytometry , the t- and b - cell phenotype in the bone marrow ( bm ) , spleen , and the mesenteric lymph node ( mln ) of allergic and control mice was analyzed . nut allergic mice exhibited an expansion of cd4 + cd62l t cells in bm and spleen ; a similar trend was noted in the mln . there was expansion of cd80 + b cells in bm and spleen and mln and cd62l cells in bm and spleen . interestingly , among cd80 + b cells , significant proportion was cd73 particularly in the mln . these data demonstrate that during the early establishment of hazelnut allergy there is ( i ) expansion of cd4+cd62l t - cell subsets in both the bm and the periphery , ( ii ) expansion of cd80 + and cd62l b - cell subsets in bm and the periphery , and ( iii ) a significant downregulation of cd73 on a subset of b cells in mln .
PubmedSumm118842	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: this was a cross - sectional epidemiological survey of the nationwide , population - based norwegian childhood diabetes registry ( ncdr ) . the participants were recruited from the ncdr between 1 april 2010 and 31 march 2011 . in our study , a total of 1816 individuals with type 1 diabetes aged 1119 years in the ncdr were invited to participate in the study . the ncdr , a nationwide , population - based registry established in 2006 , includes all newly diagnosed children with diabetes . all the pediatric departments in norway perform an annual examination of all their patients with diabetes and report the results to the ncdr . the final sample consisted of 770 children and adolescents with type 1 diabetes aged 1119 years ( 42.40% response rate ) . participants were somewhat younger than nonparticipants ( 14.6 vs. 15.1 years ; p 0.001 ) , had slightly lower hba1c ( 8.5 vs. 8.7% ; p 0.01 ) , and had somewhat shorter duration of type 1 diabetes ( 5.3 vs. 6.1 years ; p 0.001 ) than nonparticipants ; however , the effect sizes were very small ( 0.2 , 0.1 , and 0.2 , respectively ) . these groups did not differ with respect to zbmi or age at onset of type 1 diabetes . written consent was obtained from participants and their parents , if the participant was below the age of 16 years . questionnaires were distributed to the participants at their regularly scheduled appointments at their local outpatient diabetes clinics . the deps ( 14 ) was the first measure designed to screen for deb in type 1 diabetes , such as insulin restriction to lose weight . the original instrument consisted of 28 items but has recently been revised to create the deps - r , a brief 16-item version that can be completed in less than 10 min and has demonstrated good psychometric properties ( 13 ) . responses are scored on a 6-point likert scale ranging from 0 to 5 , and higher scores indicate greater pathology . the eat ( 12 ) is a generic screening measure of eating pathology used internationally to detect pathologic eating attitudes and behaviors . a 12-item norwegian version , eat-12 has been developed ( 15 ) and has demonstrated adequate psychometric properties ( 16 ) . hba1c was determined for all participants by high - performance liquid chromatography ( tosoh g7 ; tosoh europe n.v . , tessenderlo , belgium ) at the same central diabetes control and complications trial standardized laboratory . bmi was calculated from weight and height ( kg / m ) and standardized to a z - score ( zbmi ) according to age and sex because the participants were primarily younger than 18 years using the centers for disease control and prevention ( cdc ) growth charts for 2000 ( 17 ) . weight was categorized in four groups according to the world health organization ( 18 ) : underweight ( bmi < 18.5 kg / m ) , normal weight ( bmi 18.524.9 kg / m ) , overweight ( bmi 2529.9 kg / m ) , and obese ( bmi 30 kg / m ) . data were assessed as part of the annual extended diabetes examination at the local diabetes outpatient clinic . nonparametric tests were used for skewed data . for the deps - r and the eat-12 , convergent validity between the deps - r and the eat-12 was investigated with spearman population correlation coefficient ( ) . in line with cohen ( 19 ) , correlations of 0.100.29 were interpreted as small , 0.300.49 as medium , and 0.501.0 as large . correlations were also carried out to explore relationships with other constructs hypothesized to covary with deps - r scores , such as hba1c , zbmi , age , and sex . a principal axis factoring ( paf ) was used to explore the factor structure of deps - r . the data were considered suitable for paf because the kaiser - meyer - olkin measure of sampling adequacy value was > 0.6 and the bartlett test of sphericity value was significant . effect sizes were calculated by means of cohen d value , and the guidelines used for interpreting this value were as follows : 0.20 , small effect ; 0.50 , moderate effect ; and 0.80 , large effect ( 19 ) . statistical analyses were conducted with spss version 18 ( ibm corporation , armonk , ny ) . this was a cross - sectional epidemiological survey of the nationwide , population - based norwegian childhood diabetes registry ( ncdr ) . the participants were recruited from the ncdr between 1 april 2010 and 31 march 2011 . in our study , a total of 1816 individuals with type 1 diabetes aged 1119 years in the ncdr were invited to participate in the study . the ncdr , a nationwide , population - based registry established in 2006 , includes all newly diagnosed children with diabetes . all the pediatric departments in norway perform an annual examination of all their patients with diabetes and report the results to the ncdr . the final sample consisted of 770 children and adolescents with type 1 diabetes aged 1119 years ( 42.40% response rate ) . participants were somewhat younger than nonparticipants ( 14.6 vs. 15.1 years ; p 0.001 ) , had slightly lower hba1c ( 8.5 vs. 8.7% ; p 0.01 ) , and had somewhat shorter duration of type 1 diabetes ( 5.3 vs. 6.1 years ; p 0.001 ) than nonparticipants ; however , the effect sizes were very small ( 0.2 , 0.1 , and 0.2 , respectively ) . these groups did not differ with respect to zbmi or age at onset of type 1 diabetes . was obtained from participants and their parents , if the participant was below the age of 16 years . questionnaires were distributed to the participants at their regularly scheduled appointments at their local outpatient diabetes clinics . the deps ( 14 ) was the first measure designed to screen for deb in type 1 diabetes , such as insulin restriction to lose weight . the original instrument consisted of 28 items but has recently been revised to create the deps - r , a brief 16-item version that can be completed in less than 10 min and has demonstrated good psychometric properties ( 13 ) . responses are scored on a 6-point likert scale ranging from 0 to 5 , and higher scores indicate greater pathology . the eat ( 12 ) is a generic screening measure of eating pathology used internationally to detect pathologic eating attitudes and behaviors . a 12-item norwegian version , eat-12 has been developed ( 15 ) and has demonstrated adequate psychometric properties ( 16 ) . hba1c was determined for all participants by high - performance liquid chromatography ( tosoh g7 ; tosoh europe n.v . , tessenderlo , belgium ) at the same central diabetes control and complications trial standardized laboratory . bmi was calculated from weight and height ( kg / m ) and standardized to a z - score ( zbmi ) according to age and sex because the participants were primarily younger than 18 years using the centers for disease control and prevention ( cdc ) growth charts for 2000 ( 17 ) . weight was categorized in four groups according to the world health organization ( 18 ) : underweight ( bmi < 18.5 kg / m ) , normal weight ( bmi 18.524.9 kg / m ) , overweight ( bmi 2529.9 kg / m ) , and obese ( bmi 30 kg / m ) . data were assessed as part of the annual extended diabetes examination at the local diabetes outpatient clinic . nonparametric tests were used for skewed data . for the deps - r and the eat-12 , convergent validity between the deps - r and the eat-12 was investigated with spearman population correlation coefficient ( ) . in line with cohen ( 19 ) , correlations of 0.100.29 were interpreted as small , 0.300.49 as medium , and 0.501.0 as large . correlations were also carried out to explore relationships with other constructs hypothesized to covary with deps - r scores , such as hba1c , zbmi , age , and sex . a principal axis factoring ( paf ) was used to explore the factor structure of deps - r . the data were considered suitable for paf because the kaiser - meyer - olkin measure of sampling adequacy value was > 0.6 and the bartlett test of sphericity value was significant . effect sizes were calculated by means of cohen d value , and the guidelines used for interpreting this value were as follows : 0.20 , small effect ; 0.50 , moderate effect ; and 0.80 , large effect ( 19 ) . statistical analyses were conducted with spss version 18 ( ibm corporation , armonk , ny ) . as shown below , mean age of the 770 participants was 14.6 ( 2.1 ) years and age at onset of type 1 diabetes was 8.9 ( 3.6 ) years . mean type 1 diabetes duration was 5.3 ( 3.4 ) years , mean zbmi was 0.3 ( 0.9 ) , and mean hba1c was 8.5% ( 1.4% ) . pubertal state was categorized by tanner stage 15 as prepubertal ( tanner stage 1 ) pubertal ( tanner stage 24 ) , and postpubertal ( tanner stage 5 ) . participant characteristics the cronbach coefficients for the deps - r were 0.89 , 0.81 , and 0.90 for the entire sample , males , and females , respectively . for the eat-12 , coefficients were 0.74 for the whole sample , 0.63 for males , and 0.76 for females . the deps - r was significantly and positively correlated with the eat-12 ( = 0.65 ; p 0.01 ) ( table 2 ) . additional significant , although small , correlations were found between the deps - r and zbmi ( = 0.28 ; p 0.01 ) , hba1c ( = 0.22 ; p 0.01 ) , age ( = 0.27 ; p 0.01 ) , and sex ( = 0.27 ; p 0.01 ) . the eat-12 was also significantly correlated with hba1c ; however , this was an even smaller correlation ( = 0.08 ; p 0.05 ) . correlations between deps - r and eat-12 , hba1c , zbmi , age , and sex the deps - r norms ( sd ) for the total sample , males , and females were as follows : 11.0 ( 10.7 ) , 7.7 ( 7.4 ) and 14.2 ( 12.4 ) , respectively . mean deps - r score was more than three times higher in the obese group than in the underweight group , and two times higher in the oldest than in the youngest age group . table 3 presents the deps - r scores according to sex , age , and zbmi category . norms according to different categories of age and weight after the suitability of data for factor analysis was assessed , paf was performed on the 16 items of the deps - r . the kaiser - meyer - olkin value was 0.92 , and the bartlett test of sphericity reached statistical significance , supporting the factorability of the correlation matrix . paf revealed three components with eigenvalues > 1 , explaining 38.7 , 8.5 , and 7.4% of the variance , respectively , accounting for a total of 54.6% of the variance . on the basis of eigenvalues and inspection of the scree plot , three components were chosen for further investigation . to assist in the interpretation of these three components , all three components showed relatively strong loadings and items loaded exclusively on one component , with the exception of one item ( item 13 ) . further examination of the three factors was conducted by running correlations with the deps - r total score and hba1c . factor 1 correlated more strongly with both the deps - r total score ( 0.91 ; p < 0.001 ) and hba1c ( 0.27 ; p < 0.001 ) than did factors 2 ( 0.88 ; p < 0.001 and 0.16 ; p < 0.001 , respectively ) and 3 ( 0.47 ; p < 0.001 and 0.09 ; p < 0.05 , respectively ) pattern matrix for paf with oblimin rotation of three - factor solution of the deps - r items to examine sex differences in factor structure , the paf was also conducted separately for males and females . when investigating males only , however , the intercorrelations among the items were not strong enough ( 20 ) , and consequently the data were not considered appropriate for factor analysis . as shown below , mean age of the 770 participants was 14.6 ( 2.1 ) years and age at onset of type 1 diabetes was 8.9 ( 3.6 ) years . mean type 1 diabetes duration was 5.3 ( 3.4 ) years , mean zbmi was 0.3 ( 0.9 ) , and mean hba1c was 8.5% ( 1.4% ) . ( tanner stage 1 ) pubertal ( tanner stage 24 ) , and postpubertal ( tanner stage 5 ) . participant characteristics the cronbach coefficients for the deps - r were 0.89 , 0.81 , and 0.90 for the entire sample , males , and females , respectively . for the eat-12 , coefficients were 0.74 for the whole sample , 0.63 for males , and 0.76 for females . the deps - r was significantly and positively correlated with the eat-12 ( = 0.65 ; p 0.01 ) ( table 2 ) . additional significant , although small , correlations were found between the deps - r and zbmi ( = 0.28 ; p 0.01 ) , hba1c ( = 0.22 ; p 0.01 ) , age ( = 0.27 ; p 0.01 ) , and sex ( = 0.27 ; p 0.01 ) . the eat-12 was also significantly correlated with hba1c ; however , this was an even smaller correlation ( = 0.08 ; p 0.05 ) . correlations between deps - r and eat-12 , hba1c , zbmi , age , and sex the deps - r norms ( sd ) for the total sample , males , and females were as follows : 11.0 ( 10.7 ) , 7.7 ( 7.4 ) and 14.2 ( 12.4 ) , respectively . mean deps - r score was more than three times higher in the obese group than in the underweight group , and two times higher in the oldest than in the youngest age group . table 3 presents the deps - r scores according to sex , age , and zbmi category . after the suitability of data for factor analysis was assessed , paf was performed on the 16 items of the deps - r . the kaiser - meyer - olkin value was 0.92 , and the bartlett test of sphericity reached statistical significance , supporting the factorability of the correlation matrix . paf revealed three components with eigenvalues > 1 , explaining 38.7 , 8.5 , and 7.4% of the variance , respectively , accounting for a total of 54.6% of the variance . on the basis of eigenvalues and inspection of the scree plot , three components were chosen for further investigation . to assist in the interpretation of these three components , all three components showed relatively strong loadings and items loaded exclusively on one component , with the exception of one item ( item 13 ) . further examination of the three factors was conducted by running correlations with the deps - r total score and hba1c . factor 1 correlated more strongly with both the deps - r total score ( 0.91 ; p < 0.001 ) and hba1c ( 0.27 ; p < 0.001 ) than did factors 2 ( 0.88 ; p < 0.001 and 0.16 ; p < 0.001 , respectively ) and 3 ( 0.47 ; p < 0.001 and 0.09 ; p < 0.05 , respectively ) . pattern matrix for paf with oblimin rotation of three - factor solution of the deps - r items to examine sex differences in factor structure , the paf was also conducted separately for males and females . when investigating males only , however , the intercorrelations among the items were not strong enough ( 20 ) , and consequently the data were not considered appropriate for factor analysis . this study replicates and extends previous research demonstrating the psychometric properties of the deps - r for children and adolescents . internal consistency was found to be very good ( 0.89 ) and consistent with the original validation study of deps - r ( 13 ) , which reported a cronbach of 0.86 . in contrast , the cronbach for eat-12 was 0.74 in our study . data also supported the construct validity of the deps - r , as indicated by significant and positive correlations with the eat-12 . additional positive , although relatively weak , correlations were found with hba1c , zbmi , and age , constructs previously found to be associated with deb ( 13,21 ) . the relatively small correlations between the deps - r and other variables are in line with earlier studies ( 13 ) . this underscores the importance of screening for deb in young patients with type 1 diabetes , because clinical variables such as zbmi and hba1c seem to be poor indicators of deb in this population . when comparing the deps - r with the eat-12 , the deps - r generally appears to be a better screening tool than the eat-12 for deb in young patients with type 1 diabetes . in addition to convincing internal consistency , the deps - r was more strongly correlated with hba1c than was the eat-12 , although both correlations were relatively weak . also , previous research comparing the deps with the 26-item eat found that deps scores were more strongly correlated with formally diagnosed eating problems than were eat scores . these findings might be explained by the fact that the deps and the deps - r can identify diabetes - specific deb , such as insulin omission to lose weight , which is a core feature of deb in type 1 diabetes . such diabetes - specific behaviors are not likely to be detected by the use of generic screening tools , indicating the risk of false negatives associated with these measures . norms of the deps - r were established in this study , and significant differences were found between males and females . our results are similar to those reported in the previous deps - r validation study ( 13 ) . the norms were additionally categorized according to zbmi and age and demonstrated a threefold increase in debs in the obese group relative to the underweight group and a twofold increase in the oldest age group ( 1719 years ) relative to the youngest age group ( 1113 years ) . determining fixed norms is challenging because of the variability in mean scores between different weight and age categories . in a clinical setting , we therefore recommend interpreting the deps - r score in relation to the patients zbmi and age . both higher zbmi and higher age appear to be risk factors for the development of debs among adolescents and children with type 1 diabetes . this finding is consistent with studies of eating pathology in the general population ( 22,23 ) . because the factor structure of the deps - r has not been previously reported , paf was conducted . although our model identified three factors , it is difficult at this point to establish obvious subscales related to these three factors . one possible interpretation is that factor 1 appears to address maladaptive eating habits , factor 2 the preoccupation with thinness or weight , and factor 3 the concept of maintaining high blood glucose values to lose weight . further examination of the three factors showed that factor 1 correlated more strongly with hba1c than did factors 2 and 3 . even though three factors were identified , it is unclear at this time whether the deps - r would benefit from using this factor structure for scoring purposes . the ease of administration and short administration time already make the deps - r clinically useful as a screening tool in busy clinical settings . nonetheless , the factor structure could be worth considering for further psychometric work on the deps - r . it is possible that scores on each factor could facilitate treatment recommendations according to which factors the individual scores highest . as expected , and in line with other studies of deb ( 13,22 ) , females scored significantly higher than males on both the deps - r and the eat-12 . this is consistent with previous research demonstrating that females are at higher risk of developing deb than males , both among patients with type 1 diabetes and in the general population ( 24 ) . it is also possible that males have underreported their symptoms of eating pathology compared with females . this has also been suggested in studies of other types of pathology ( 25,26 ) . further , when males and females were analyzed separately , internal consistency and construct validity of the deps - r were stronger among females . for example , the cronbach coefficient was lower among males ( 0.81 ) than among females ( 0.90 ) . weaker validity among males has been previously demonstrated in studies conducted with other measures of disordered eating ( 21,27 ) . because of sex disparities in prevalence rates of disordered eating ( 28 ) , assessment tools have largely been developed with female populations ; however , some studies suggest that traditional assessments may fail to provide a comprehensive assessment of male - specific eating , weight , and shape concerns ( 29 ) . items focused predominantly on restricted eating and a desire for thinness may not reflect the dual presence of a drive for thinness and a drive for muscularity that characterizes the lean , mesomorphic body ideal unique to boys and men . this may contribute to the lower validity coefficients for the deps - r among males in this study and raises the general issue of whether existing screening tools provide an adequate assessment of deb among men . in norway , all patients with type 1 diabetes are offered the same modern and intensive insulin treatment independent of social status . the strengths of this study include the high number of participants , the population - based national registry inclusive of > 95% of all eligible children and adolescents , and the validation of deps - r against an established measure of disturbed eating and somatic data . first , the response rate was relatively low ( 42% ) , and participants were on average 6 months younger with a shorter duration of illness ; however , effect sizes were small . second , it fails to compare the deps - r with a diagnostic interview such as the eating disorder examination ( 30 ) . comparison with the eating disorder examination would allow an investigation of the ability of the deps - r to identify clinical eating disorder diagnoses . future research is warranted to validate the deps - r against a diagnostic interview . in conclusion , because of the significant risks of morbidity and mortality associated with the occurrence of disordered eating and type 1 diabetes together in youth , screening and early intervention for deb should be routinely included in standard diabetes care ( 3 ) . the deps - r is a valid screening tool for deb in type 1 diabetes , is easy to administer , and is a potentially important addition to clinical practice . there were significant differences in deps - r scores according to sex , age , and zbmi , and we therefore recommend that these aspects be considered when interpreting deps - r scores . Output:	objectivethe purpose of this study was to examine the psychometric properties of the diabetes eating problem survey revised ( deps - r ) in a large sample of young patients with type 1 diabetes , to establish norms , and to validate it against the eating attitudes test12 ( eat-12).research design and methodsa total of 770 children and adolescents aged 1119 years with type 1 diabetes completed the deps - r and the eat-12 . in addition , age- and sex - standardized bmi and hba1c data were obtained from the norwegian childhood diabetes registry . in addition to tests of validity , principal axis factoring was conducted to investigate the factor structure of the 16-item deps-r.resultsthe deps - r demonstrated satisfactory cronbach ( 0.89 ) and was significantly correlated with the eat-12 ( 0.65 ; p < 0.01 ) , indicating convergent validity . the mean ( sd ) deps - r scores were 11.0 ( 10.7 ) for the total sample and 7.7 ( 7.4 ) and 14.2 ( 2.4 ) for males and females , respectively.conclusionsthis study replicates and extends previous research demonstrating the psychometric properties of the abbreviated 16-item deps - r . findings support the utility of this important screening tool to identify disturbed eating in young patients with type 1 diabetes .
PubmedSumm118843	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: a 63-year old male former construction worker was referred for massage therapy for treatment of debilitating low - back pain . he had pain in all areas of the back ; although he sometimes experienced cervical pain and/or thoracic pain , the majority of pain was in the lumbar area . his objective was to reduce pain medication ( percocet ) , prescribed at 7.5 mg 4 times daily ; he stated that it made him feel lethargic and disoriented . the subject was chosen based on his interesting condition of having multiple diagnoses , any one of which could have been responsible for his low - back pain : osteoarthritis , scoliosis , spinal stenosis , and degenerative disc disease . he was also diagnosed with hypertension , controlled with medication and not relevant to this study . normal medical treatment protocols for these conditions include pain medication and muscle relaxants , anti - inflammatory drugs , physical therapy and , in some cases , surgery . it is the most common cause of job - related disability and a leading contributor to missed work days . back and older adults and poorer adults are more likely to have back pain than other groups . back pain is a condition in which the sufferer self - limits , deciding what activities they are and are not able to do . a 2010 study published in complementary therapies in medicine states a problem frequently encountered in the massage profession : doctors want an evidence base for interventions , while massage therapists perceive patient reports of benefitting as evidence . a 2012 study on the development and validations of client expectations noted that clients tend to think positively of massage and their massage therapists , and that client expectations contribute to positive changes in pain and serenity . massage therapists should remember that people who have a positive outlook on their health may possibly still be suffering from an undiagnosed condition causing their pain . a similar 2010 study by furlan et al . reviewed efficacy , cost - effectiveness , and harms of acupuncture , spinal manipulation , mobilization , and massage in the management of back , neck , and/or thoracic pain . massage was found to be superior to placebo treatment or no treatment only among participants with acute / sub - acute low - back pain , but was found to be significantly better than physical therapy in improving back pain . zheng et al . compared the use of lumbar tender point deep - tissue massage , with and without traction , on 64 subjects with chronic low - back pain , concluding massage and lumbar traction produced better improvement in the pressure pain threshold , muscle hardness , and pain than lumbar traction alone . studies integrating massage with other treatments are becoming more common , as medical professionals are becoming more willing to include massage in their treatment protocols . a 2011 study of 401 subjects published in the annals of internal medicine concluded that massage may be effective for treatment of low - back pain , with benefits lasting at least six months after receiving weekly massage for ten weeks . outcomes were compared for patients receiving relaxation massage , patients receiving structural massage , and patients receiving the commonly prescribed protocol of physical therapy and pain medication . both types of massage were found to be more effective than the usual protocol , with no clinical meaningful difference between the two types of massage . the research question for this case study was whether a subject with chronic pain who has been diagnosed with so many different back pathologies could be helped by massage . the positive results achieved , and the articles cited , demonstrate that massage may help those with chronic low - back pain and multiple diagnoses of pain - causing conditions . the practitioner works at a multiprofessional natural health clinic . she is licensed as an lmtb in north carolina , and has additional training in various modalities of massage therapy and movement education . the referring physician had systematically assessed the subject s condition , including physical examination as well as mri . usual tools for assessing subjects presenting with low - back pain include physical examination , palpation , observation of gait and posture , the use of orthopedic tests , and radiography . the subject stated that his back pain started when he was about 35 years of age ; that he tried for years to ignore it and kept on working but , as he aged , it became more debilitating . by age 50 , he was down to working 2 to 3 hours per day ( self - employed in construction ) , and he applied for disability in 2006 . during the last year before going on disability , the subject stated that the physical therapy primarily consisted of lying flat on a table and raising his legs one at a time , which he felt caused him further pain . he estimated that he attended less than a dozen sessions over a period of a couple of months . at the initial massage therapy session , the subject indicated on the oswestry disability index that his pain level was 5 , and that it varied anywhere from mild to debilitating , depending on his activities . he mentioned that the index offered answers that did not exactly describe his case and made additional comments on it . he stated his pain and stiffness seem worse during cold weather , and attributed that to his being more active outdoors in warmer months . if he skipped his morning medication , by noon his pain level was at 78 ( his statement ; the odi stops at 5 for maximum pain ) . he could only sleep comfortably on his side , waking whenever he turned over , although he stated falling back to sleep relatively easily . he could not sit for more than a half hour without having to stand , and could not stand for longer than 10 to 15 minutes without his pain increasing . he estimated that he could not walk more than a quarter of a mile without debilitating pain . he reported sitting down to put his pants on and being unable to lift over 20 lbs . one hour in a car sent his pain level to 78 which restricted many activities and social life for two years prior to the massage intervention . the subject s goal was to become more pain - free and less dependent on pain medication . he would like to increase strength and flexibility ; he believed he could be more physically active if he felt better . he was on percocet , prescribed 4x per day , but stated he would like to get by with three tablets per day , and would like to reach the point of not needing it at all . based on the literature review supporting that both relaxation massage and deeper work are beneficial to low - back pain , the therapy chosen was swedish massage from the cervical to the lumbar area , followed by deep myofascial release strokes and the use of muscle stripping . swedish full - body massage was performed first with the intent of relaxing the subject and warming his muscles to receive deeper specific work in his lower back and gluteal areas . as he was in constant pain prior to receiving massage , after the initial focus on his entire back and gluteal muscles , the same techniques were performed on his legs , as he stated his posture had changed so much over the years ; i believed it was best to work his lower extremities with the intention to support the work on his lower back . the subject completed an oswestry disability index , also known as the oswestry low back pain disability questionnaire , prior to the first session , and following the fourth session . the questionnaire has been in use since 1980 ; it is one of the most commonly recommended condition - specific outcome measures for spinal disorders . it is a self - reporting measure of the pain occurring during 10 different activities of daily living , with scores ranging from 0 ( the least amount of pain ) to 5 ( the most amount of pain ) . the subject additionally made subjective statements on decreased pain levels and decreased need for medication , and positive effects on activities of daily living after each session . this report has been prepared using the adaptation of the care guidelines for therapeutic massage and bodywork publications . finances necessitated a treatment plan that the subject could afford : 60 minutes of massage once per week for six weeks and then reevaluation , in the hope that he would be able to receive regular maintenance care thereafter . the subject is dependent on disability income and was unable to commit to more frequent visits . techniques were chosen based on my 14 years of experience in working with clients who are in pain , and the research reviewed that supports the use of massage therapy . finances necessitated a treatment plan that the subject could afford : 60 minutes of massage once per week for six weeks and then reevaluation , in the hope that he would be able to receive regular maintenance care thereafter . the subject is dependent on disability income and was unable to commit to more frequent visits . techniques were chosen based on my 14 years of experience in working with clients who are in pain , and the research reviewed that supports the use of massage therapy . the question being examined was : did the subject s pain decrease across the treatment period ? table 1 , the scores from the oswestry disability index at the first and last ( fourth ) sessions , showed a 22% overall reduction of the odi score ( reduction from severe disability category ( 4160% ) to moderate disability category ( 2140% ) , a clinically relevant change for this patient . the subject reported feeling so much better that we mutually agreed to end the study at four sessions instead of the six originally discussed in the treatment plan . this was because the subject s reported pain was at zero after the fourth session . summary of oswestry disability index scores comparing category and total score values from first and last visits the subject stated feeling optimistic about progress after the first massage , although he felt sore for a couple of days . , he was thrilled at the improvement in his back pain , and stated that his injured shoulder also felt more flexible and less painful when moving his arm . he reported being able to stretch out his medication doses over longer periods , cutting out at least one of the doses daily . he stated feeling so much better a couple of days after the third session , he rode his bicycle for the first time in several years and had ridden it daily for short rides the four days immediately prior to the fourth session . he reported his shoulder had continued to feel better and being able to raise his arm over his head without feeling any pain , which he had not been able to do since injuring it in 2010 . he related the pain that had bothered him the most at the beginning , in his lower back at the sacral area and left gluteus , was gone altogether . at the first maintenance visit , he continued alternating a lot between sitting and standing , but stated that it is a habit he had for so many years , that he may be doing it almost automatically instead of because of actually being in pain . he reported taking two percocet per day , with occasional days of feeling so well he took only one . he is treated at the v.a . and sometimes waits months for an appointment . ) the subject reported more vitality in general since reducing his pain medication , which he had stated in the initial interview left him feeling lethargic and disoriented . his posture and gait showed no noticeable changes , but he reported feeling more at ease performing activities of daily living , and after years of pain and limited abilities , being grateful to find help . his ability to sit and stand more comfortably for longer periods of time increased , whereas he formerly got up and down frequently because of discomfort if he stayed too long in either position . no specific measures of strength were done during the study , and he still does not try to do any lifting of heavy objects . although he is not 100% pain free , and will probably never be due to all the diagnosed problems he has , his increase in feeling better and his decrease in having to be so heavily medicated improved his outlook and his quality of life . it is not unusual to get good results from just a few sessions ; there are studies demonstrating that only a massage or two produced positive results . different clients experience different results because many factors affect every individual : cause of dysfunction , duration , degree of pain and disability , psychological effects , and even how the condition has affected relationships with friends and family members . as with all studies based on self - reporting instead of controlled scientific observation , it is impossible to definitely attribute improvement to true effect , placebo effect , or both . massage is noninvasive , generally available , can produce timely results , and is more cost - effective than most other treatments for chronic low - back pain . it is likely that , as more research validates the efficacy of massage therapy , more primary care physicians will be willing to integrate massage therapy into treatment protocols and refer patients to licensed massage therapists . Output:	objectivesto study the effects of massage on chronic low - back pain in a patient with four different diagnoses : osteoarthritis , scoliosis , spinal stenosis , and degenerative disc disease . the patient s goal was to cut down on the amount of pain medication he takes.methodsa 63-year - old man with chronic back pain received four massages across a twenty - day period . progress was recorded using the oswestry low back pain scale , as he self - reported on levels of pain and interference with his activities of daily living.resultsimprovement was noted in 9 out of 10 measurements of self - reported pain and activities of daily living , with the only exception being his ability to lift heavy objects , which remained unchanged . the most dramatic differences were improvements in his ability to walk , and in the changing degrees of pain . the client also self - reported being able to decrease his pain medication and the ability to ride his bicycle for the first time in years.conclusionsmassage therapy is a promising treatment for chronic low - back pain for patients who may have multiple pathologies , any one of which could be responsible for the condition . further study is encouraged to determine the efficacy of massage therapy as a readily accessible , lower - cost alternative to more invasive therapies and as an adjunct to regular medical care , when appropriate .
PubmedSumm118844	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: a 33-year - old male with a history of supraventricular tachycardia presented to us with frequent palpitations . the tachycardia at that time was mapped to the right free wall . despite giving multiple ablation pulses at the site of earliest retrograde atrial electrogram , the pathway could not be eliminated . repeat ablation was considered as he remained symptomatic and did not wish to remain on flecainide . an atrial ectopic beat resulted in manifest pre - excitation with qrs morphology suggestive of a right antero - lateral accessory pathway ( delta wave + ve in v1 , ii , iii and avf , small r in v1 and late qrs transition in chest lead ) . during the electrophysiology study , intracardiac electrograms showed a basal sinus cycle length of 1000 ms with an ah interval of 90 ms and hv interval of 30 ms . with incremental atrial pacing , maximum pre - excitation was noted at 400 ms ( fig . there was no evidence of decremental pathway conduction , and the anterograde refractory period was 390 ms . atriofascicular fiber - mediated tachycardia could be ruled by lack of decremental conduction property along with intact retrograde accessory pathway conduction . va interval during the tachycardia and v pacing was approximately 140 ms over the pathway . a duodecapolar catheter was placed at the tricuspid annulus ( ta ) for better delineation of the accessory pathway . mapping of the tricuspid annulus was done with a 3.5 mm irrigated thermacool catheter via sr2 sheath . ventricular pacing from the right ventricular ( rv ) apex showed earliest retrograde a at the ta 5 electrode ( corresponding to the 8 o'clock position in the left anterior oblique view ) . in view of previous failed ablations , differential pacing from the rv confirmed the oblique course of the pathway . during anterior paraseptal rv pacing , the local ventriculoatrial ( va ) interval was long at the ta 5 electrode ; during posterobasal rv pacing , the local va interval was short at the ta 5 electrode . at the 8 o'clock tricuspid annular position , bipolar electrograms of the distal mapping catheter electrodes showed good va fusion and earliest retrograde a. there was a small pathway potential noted at the onset of a wave ( fig . 2a ) , but the unipolar electrograms showed that the pathway potential corresponded to the second electrode ( fig . since the earliest retrograde a site in patients with oblique pathway might not be the ideal site to target , annulus was mapped for a sharp and early pathway potential . after repositioning the catheter , local electrode showed va signal with sharp and early accessory pathway potential ( fig . unipolar electrogram confirmed that the sharp signal was from the distal electrode ( fig . even though there was no local va fusion , the pathway potential appeared to be early at that site . radiofrequency ablation ( power 50 w , temperature 50 ) delivered at that site resulted in immediate interruption of pathway conduction with local va separation . catheter ablation of the accessory pathway ( ap ) is the treatment of choice for patients with symptomatic wolff although the site with the shortest local va interval during orthodromic av reentrant tachycardia or ventricular pacing is often considered the optimal target for pathway ablation , this has been debated . most aps described had their atrial and ventricular insertions in separate histological sections consistent with an oblique course . the direction of atrial and ventricular wavefronts along the tricuspid annulus was reversed by differential atrial and ventricular pacing from the opposite sides of the aps . reversing the ventricular wavefront increased the local va interval by > 15 ms in 91 of 106 patients ( 88% ) . mapping during longer va intervals identified accessory pathway potential in 102 of 114 patients ( 89% ) . ablation at the accessory pathway recording site eliminated ap conduction with a median of one radiofrequency ablation . the ablation was targeted at the site of early and sharp accessory pathway potential and not at the site of earliest retrograde atrial electrogram . a single ablation pulse eliminated the pathway conduction immediately , again confirming the oblique course of the pathway . the utility of unfiltered unipolar electrograms for successful ablation of the accessory pathway has been extensively studied . barlow et al . studied the characteristics of the unipolar electrogram that are useful in predicting successful ablation of accessory pathways . a qs pattern was seen at 90% of permanently successful sites as compared to 55% of the unsuccessful sites . activation times were significantly shorter at permanently successful sites than at unsuccessful sites ( p value < 0.0001 ) . furthermore rapid these features were equally applicable for both atrial and ventricular potential mapping . nevertheless , filtered bipolar electrogram is the preferred mapping tool because of its concentration on local activation . the unipolar electrogram provides information about the onset of distant activation , precise timing of the local activation and the quality of tissue contact by the catheter . the bipolar electrogram reflects the equal influence of two electrodes separated by the interelectrode distance , whereas the unipolar electrogram reflects the activity under one particular electrode . consequently , the unipolar recording from the distal tip of an ablation catheter provides more accurate and relevant information than a bipolar recording from the distal pair of electrodes . even in our patient , the initial catheter position ( position a ) showed good va fusion with accessory pathway potential in the bipolar electrogram ; the unipolar electrograms localized the potential to the second electrode . after repositioning , the sharp pathway potential was recorded at both distal unipolar and bipolar electrograms . this has to be considered especially in patients with a history of previous failed ablation . differential atrial and ventricular pacing protocols should be utilized to demonstrate the course and to identify the site of successful ablation . the site showing early and sharp accessory pathway potential in both the bipolar and unipolar distal electrode should be targeted . Output:	radiofrequency ablation has been shown to be a safe and effective treatment strategy for the management of symptomatic patients with wolff parkinson white syndrome . it is supported by a success rate of 95% and a recurrence rate of less than 5% . however , ablation of accessory pathways can be challenging at times . the causes for failure can be grouped into three categories unusual location of the pathway , technical difficulties in delivering the ablation and localization error [ 1 ] . in this case report we are reporting a case of a young male who presented to us with symptomatic wolff parkinson white syndrome with two failed prior ablations at another institution . this case illustrates the importance of knowing accurate localization and course of the accessory pathway by utilizing the unipolar and bipolar electrograms simultaneously during radiofrequency ablation .
PubmedSumm118845	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: Output:	these are peer - reviewed poster - platform submissions finalized by the scientific program committee . a total of 153 abstracts ( 14 platforms [ pp1 through pp14 ] & 139 posters [ 1 through 139 ] ) were selected from 161 submissions to be considered for presentation during november 4 8 , 2011 , at the hilton baltimore hotel , to pathologists , cytopathologists , cytotechnologists , residents , fellows , students , and other members of cytopathology - related medical and scientific fields .
PubmedSumm118846	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: fluorescence spectroscopy represents an appropriate technique for investigating structural properties of fluorophores in liquid system . the electronic absorption and emission spectra of molecules in solution , respectively , give reliable information about solvation effects in the ground and excited states . in general , fluorescence emission of molecules is governed by kasha s rule which states that fluorescence normally occurs from the lowest vibrational level of the first excited electronic state . it is obvious from this rule that fluorescence should be independent on the excitation wavelengths . on the other hand , it is known for some time , that the fluorescence bands maxima of some system ( polar molecules ) can shift towards longer wavelengths with an increase in the excitation wavelength [ 215 ] . since this effect is observed only under conditions of restricted mobility , it has been used as a potential tool to estimate the fluorophore ( both intrinsic and extrinsic ) environment in the organized biological assemblies as membranes , micelles , and proteins [ 215 ] . it is generally accepted that wavelength - dependent fluorescence involves emission from multiple states or different conformers of the molecule . in a medium where inhomogeneous distribution of species appears , each solute molecule with its own surrounding possesses different absorption and fluorescence band . as a result of this the absorption and emission spectra possess a complex nature i.e. , an inhomogeneous broadening of electronic spectra . these conformations of solute molecules interchange rapidly in a fluid medium whereas in a rigid medium the probe molecules are trapped in various geometric configurations . the fluorescence intensity maximum position of the molecule under study in thf glass at 77 k shows considerable dependence on the excitation wavelengths . the origin of this behavior lies in the variety of solute - solvent interaction ( fluorescence centers ) in the ground and excited states . such assembles of solute molecules excited in a narrow band causes a photoselection of different conformers of eaadcy , which emit own characteristic band . b dipole moments in the ground and first excited states as a function of the dihedral angle a ground - state rotational potential and the corresponding rotamer distribution function n( ) , b dipole moments in the ground and first excited states as a function of the dihedral angle in the present paper , we are continuing our previous investigation of the spectral inhomogenity of eaadcy . we present results of systematic studies concerning the excitation - wavelength dependent dual fluorescence of eaadcy . steady - state and time - resolved measurements are made on molecule under study in thf at room temperature . it is found that the ratio of the fluorescence intensity of the long - wavelength and short - wavelength fluorescence bands ( iexc ( lw)/iexc ( sw ) and iem ( lw)/iem ( sw ) ) strongly depends on the observation / excitation wavelength , whereas the wavelengths of the fluorescence excitation and fluorescence bands maxima are independent on observation / excitation wavelengths . recently , several theoretical models of the solvation of molecule in liquid solvent have been developed . phenomenological description of inhomogeneous broadening of electronic spectra of organic molecules in solution has been given by nemkovich et al . [ 11 , 12 ] . they proposed a free energy diagram which describes the dependence of the free energy of the probe - environment centers ( solvates ) on the strength of the local electric field . according to nemkovich et al . , the ground - state solvate free energy can be written as : 1\documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ { u_g}(r ) = \frac{{{{\left ( { r - r_g^{eq } } \right)}^2}}}{{2f } } , $ $ \end{document}where \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ r_g^{eq } $ $ \end{document } is the electric field strength of the equilibrium solvate , f is the factor of the reaction field , which , in a linear approximation , equals to the coefficient of proportionality between the field and ground - state electric dipole moment ( g ) \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ r_g^{eq } = f{\mu_g } $ $ \end{document}. the free energy of the excited solvates is given by [ 11 , 12 ] : 2\documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ { u_e}(r ) = \frac{{{{\left ( { r - r_e^{eq } } \right)}^2}}}{{2f } } + h{\nu_0 } + \frac{f}{2}\left ( { { { \vec{\mu } } _ e } + { { \vec{\mu } } _ g } } \right)\left ( { { { \vec{\mu } } _ e } - { { \vec{\mu } } _ g } } \right ) , $ $ \end{document}where v0 is the frequency of the pure ( 00 ) electronic transition of the free probe molecule , h the planck constant , e is the dipole moment in the excited state . \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ r_e^{eq } $ $ \end{document } is the local electric field in the solvent established by the solute molecules in the thermally equilibrated excited state . from the above , it is evident that inhomogeneous broadening occurs because different set of solute molecule possesses different solvation shell and different strength of the reaction field r. the range of the inhomogeneous broadening , which dictates photoselection of the energetically different species , depends on the values of dipole moments of the dye molecules in the ground and excited states , and on the dielectric properties and structure of a solvent [ 11 , 12 ] . as it was mentioned earlier , the excitation - wavelength dependence of fluorescence band intensity is a result of the existence of energetically different luminescence centers solute molecules with different shell structure of the nearest solvent molecules ( e.g. , presence of various solute conformers having different geometries and absorbing at different wavelengths ) . in this case , it is necesary to use the rotamer distribution function n( ) determined from boltzmann s law : 3\documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ n\left ( \varphi \right ) = { e^{\frac { { - e\left ( \varphi \right ) - e\left ( { { \varphi_{eq } } } \right)}}{{rt}}}}/\int\limits_0^{180 } { { e^{\frac { { - e\left ( \varphi \right ) - e\left ( { { \varphi_{eq } } } \right)}}{{rt } } } } } d\varphi . $ $ \end{document}excited states processes are usually studied by measurements of the time - resolved emission spectra . in such experiments , light absorption promotes molecules to non - relaxed franck - condon state , which undergoes fast transition to the relaxed equilibrium singlet state . this dynamic process can be observed monitoring the time depending position of maximum of the fluorescence spectrum . the relaxation dynamic between solute and solvent molecules are generally expressed in terms of the correlation function c(t ) , defined as : 4\documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ c(t ) = \frac{{\tilde{\nu } ( t ) - \tilde{\nu } \left ( \infty \right)}}{{\tilde{\nu } ( 0 ) - \tilde{\nu } \left ( \infty \right ) } } , $ $ \end{document}where \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tilde{\nu } ( t ) $ $ \end{document } , \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tilde{\nu } ( 0 ) $ $ \end{document } , and \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tilde{\nu } \left ( \infty \right ) $ $ \end{document } are the wavenumbers of the fluorescence band maximum at times t , 0 , and . the continuum model of the solution predict an exponential decay of the correlation function , = exp(t/l ) , with a longitudinal relaxation l time ( \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ { \tau_l } = { \tau_d}\frac{{{\varepsilon_\infty } } } { { { \varepsilon_0 } } } $ $ \end{document};d denotes the dielectric relaxation time , 0 and \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ { \varepsilon_\infty } $ $ \end{document } the static and optical permittivity ) . it is important to note here that many experiments investigating solvation dynamics have shown that this model does not account fully for the observed changes of c(t ) . the solvent used in the present study ( tetrahydrofuran thf ) was the spectroscopic grade and was used without any additional purification . absorption , fluorescence excitation and emission spectra at room temperature were recorded using , respectively , a shimadzu uv-2401 pc spectrophotometer and a shimadzu rf-5301 spectrofluorometer with 5.0 nm band - widths in both excitation and emission . fluorescence measurements were carried out using the triangular cuvette with frontal excitation to minimize the effect of reabsorption . thus the errors due to fluorescence reabsorption were reduced in a way that mathematical corrections were superfluous . time - resolved emission spectra of the sample were measured applying streak camera ( c4334 - 01 hamamatsu ) and 2501 s spectrograph ( bruker optics ) . solid state nd : yag laser ( pl 2143a / ss ekspla ) and optical parametric generator ( pg 401/sh ekspla ) were used as an excitation light pulses source . to test whether the changes in the absorption , fluorescence excitation and fluorescence spectra originate from the solute conformers possesing different angles between their interatomic planes of the donor and acceptor moieties , a series of conformational semiempirical quantum mechanical calculations were carried out . we found that for eaadcy molecule the ground - state rotational potential is essentially flat ( in the range from 60 to 120 ) [ 18 , 19 ] . figure 1a shows the calculated ground - state ( s0 ) rotational potential and the corresponding rotamer distribution function n( ) determined from boltzmann s low at 298 k , for the molecule under study . according to the boltzmann s low , in the ground state about 33% of the all eaadcy molecules possess twist angle between two fragments ( donor and acceptor ) in the range from 60 to 120. thus , quantum - chemical calculations suggest the presence of various conformers in the ground state which have different geometry and absorb at different wavelengths . in addition , it should be noted that eq ( obtained using quantum - chemical calculations ) does not differ from the mean twisting angle \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ < { \varphi_n } > = \int\limits_0^{180 } { \varphi \;n\left ( \varphi \right ) } \,d\varphi $ $ \end{document } , which is convoluted with the distribution function n( ) , and equals \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ { \varphi_{eq } } = < { \varphi_n } > \cong { 90^\circ } $ $ \end{document}. as it was mentioned earlier , the range of inhomogeneous broadening depends on the values of dipole moments of the dye molecules in the ground and excited states . from the quantum - chemical calculations [ 18 , 19 ] ( see fig . 1b ) it is evident that dipole moment of eaadcy in the ground state shows a very week dependence on the dihedral angle , whereas in the first excited state planar molecule possesses five times greater dipole moment than that with perpendicular donor - acceptor arrangement ( i.e. , 15.6 d versus 3.0 d ) . the large differences between \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ { \mu_{{s_1}}}\left ( { le } \right ) $ $ \end{document } and \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ { \mu_{{s_1}}}\left ( { ict } \right ) $ $ \end{document } suggest existence of molecules possessing different solvation shell and different strength of the reaction field r. figure 2a presents the observation - wavelength dependence of fluorescence excitation spectra ( maxima position and shape of the spectra ) of eaadcy in thf at room temperature . the major observation that can be made suggests the strong dependence of the fluorescence excitation spectrum on the observation wavelength . the long - wavelength fluorescence excitation band of eaadcy are composed of at least two bands , centered at about 360 nm and 430 nm . as it was shown in fig . 2a , upon increasing the observation wavelength the intensity of the short - wavelength band at 360 nm decreases . this behavior is accompanied by an increase of the long - wavelength band centered at 430 nm . it is important to note here that each of the area under the fluorescence excitation and fluorescence ( fig . 2a and b ) curves were normalized to unity . in this case , each of fluorescence spectrum corresponds to the emission of the same number of emitting eaadcy molecules . 2fluorescence excitation spectra ( a ) and fluorescence spectra of eaadcy in thf at room temperature as a function of obs ( a ) and exc ( b ) fluorescence excitation spectra ( a ) and fluorescence spectra of eaadcy in thf at room temperature as a function of obs ( a ) and exc ( b ) we also carefully examined the excitation - wavelength dependence of fluorescence spectra of eaadcy in thf . we found that upon increasing the excitation wavelength the intensity of short - wavelength fluorescence band decreases . this behavior is accompanied by an increase of the long - wavelength emission band . analyzing the fluorescence excitation ( fig . 2b ) spectra of eaadcy in thf obtained at different observation and excitation wavelengths , it is found that the ratio of the fluorescence intensity of the long - wavelength and short - wavelength fluorescence bands ( iem ( lw)/iem ( sw ) ) strongly depend on the excitation wavelength . a typical excitation- and observation - wavelength dependent behavior 3b ) , when the excitation wavelength is increased from 360 nm to 445 nm , the ratio iem ( lw)/iem ( sw ) increases from ~0.5 to ~8 . it is important to note here that the ratio iem ( lw)/iem ( sw ) is of the solute concentration independent ( with the limit of experimental error ) . 3the ratio iexc(sw)/iexc(lw ) ( a ) and iem(lw)/iem(sw ) ( b ) as a function of obs and exc , respectively the ratio iexc(sw)/iexc(lw ) ( a ) and iem(lw)/iem(sw ) ( b ) as a function of obs and exc , respectively the steady - state fluorescence excitation spectra are also strongly observation - wavelength dependent . as can be seen ( fig . 3a ) the ratio iexc ( sw)/iexc ( lw ) undergoes a significant decrease when increasing the observation wavelength ( e.g. , from ~6.5 ( obs = 480 nm ) to ~0.8 ( obs = 605 nm ) . this observation / excitation wavelength dependence is similar to the typical red - edge effect observed in low - temperature glasses , polymer matrixes , and organized assemblies such as micelles , vesicles , proteins and membranes [ 215 ] . these results , as well as , our previous study [ 10 , 1820 ] indicate that for eaadcy a distribution of spatial conformers ( lie in difference of rotational angles between donor and acceptor moieties ) is always present ( see fig . 1 ) . when the excitation is carried out at the maximum of the absorption band , the conformers having perpendicular or nearly perpendicular geometry ( ~ 90 ) are excited . as the excitation wavelength is shifted to the red , the rotamer with different angles ( 0 < it can be concluded that ict state ( long - wavelength fluorescence band ) may be formed either by further geometrical changes of the normal conformer ( ~ 90 ) in the locally excited state or directly by excitation of flattened conformers . in order to confirm the interpretation of the steady - state measurements data , the time - resolved emission spectra and from them these measurements were carried out at 5 ns range of streak camera window , what gave us point - to point time resolution of 10.86 ps per point . figure 4 shows the emission spectra of eaadcy in thf at various times after excitation ( exc = 400 nm ) . as can be seen , upon increasing the time after excitation the short - wavelength ( le ) and long - wavelength ( ict ) fluorescence maxima positions are red - shifted . figure 4 clearly shows that a pronounced shift of the sw and lw bands occurs already at very short time after excitation . in order to make it more evident , the temporal behavior of \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tilde{\nu } _ { sw}^{\max } ( t ) $ $ \end{document } and \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tilde{\nu } _ { lw}^{\max } ( t ) $ $ \end{document } are shown in fig . 5 . fig . 4time - resolved emission spectra of eaadcy in thf at room temperature at various times after excitation ( exc = 400 nm)fig . 5time - dependence of the frequency of the short - wavelength ( sw ) and long - wavelength ( lw ) emission band maximum of eaadcy in thf time - resolved emission spectra of eaadcy in thf at room temperature at various times after excitation ( exc = 400 nm ) time - dependence of the frequency of the short - wavelength ( sw ) and long - wavelength ( lw ) emission band maximum of eaadcy in thf in order to determine the stokes - shift correlation function c(t ) , the time - dependent frequencies \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tilde{\nu } _ { sw}^{\max } ( t ) $ $ \end{document } and \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tilde{\nu } _ { lw}^{\max } ( t ) $ $ \end{document } are normalized according to eq . 4 . figure 6 illustrates the resulting c(t ) curves for short - wavelength and long - wavelength fluorescence bands . the decay times ( obtained for different exc ) of c(t ) are summarized in table 1 . analyzing the experimental decay data , it follows that the obtained \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tau_{sw}^l $ $ \end{document } and \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tau_{lw}^l $ $ \end{document } values do not depend on exc . from the \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tau_{sw}^l $ $ \end{document } and \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tau_{lw}^l $ $ \end{document } values obtained for both of the conformers ( perpendicularle form , flattenedict form ) , it is evident that the longitudinal relaxation time is very different . the ratio of the corresponding longitudinal relaxation times \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \frac{{\tau_{sw}^l}}{{\tau_{lw}^l } } $ $ \end{document } is about 3 . this large difference between \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tau_{sw}^l $ $ \end{document } and \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tau_{lw}^l $ $ \end{document } values is understandable taking into account different interactions of the conformers with the reactive electric field of the surrounding solvent . in our previous publication , it was shown that the flattened ( ict ) form of eaadcy possesses greater dipole moment in the excited state than in the ground state , while perpendicular ( le ) form of eaadcy possesses lower dipole moment value in the excited state in comparison to its value in the ground state . the following changes of dipole moment were obtained : \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \delta { \mu_{perpen . } } = - { 1}.{82}\,{\hbox{d } } $ $ \end{document } , \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \delta { \mu_{flatt . } } = { 13}.{5}\,{\hbox{d } } $ $ \end{document}. fig . 6decay of the solvent correlation function c(t ) of le ( b ) and ict ( a ) form of eaadcy in thf at room temperaturetable 1the longitudinal relaxation times ( \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tau_{sw}^l $ $ \end{document } , \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tau_{lw}^l $ $ \end{document } ) , fluorescence decay times ( sw , lw ) and preexponential factors ( asw , alw ) of eaadcy in thf\documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tau_{sw}^l\left ( { \hbox{ps } } \right ) $ $ \end{document}\documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tau_{lw}^l\left ( { \hbox{ps } } \right ) $ $ \end{document}sw ( ps)asw ( % ) lw ( ps)alw ( % ) exc = 370 nm162 2053 45.6578.20.2221.81.21exc = 390 nm170 1564 85.8366.40.2133.61.09exc = 400 nm187 2059 55.7353.30.2546.71.18exc = 420 nm182 1262 85.5543.20.2056.81.22 decay of the solvent correlation function c(t ) of le ( b ) and ict ( a ) form of eaadcy in thf at room temperature the longitudinal relaxation times ( \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tau_{sw}^l $ $ \end{document } , \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tau_{lw}^l $ $ \end{document } ) , fluorescence decay times ( sw , lw ) and preexponential factors ( asw , alw ) of eaadcy in thf the experimental decay curves were fitted to a multiexponential function \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ f(t ) = \sum\nolimits_{i = 1}^n { { a_i}\exp \left ( { - t/\tau } \right ) } $ $ \end{document } , where ai and i are the preexponential coefficient ( describing the contribution of the i - th fluorescence decay component to the total emission ) and decay time of the i - th component , respectively . the average value of , describing the goodness of the fitting procedure for all decay curves , i.e. , one- and two - exponential fitting , equals \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ { \chi^2 } = 1.2\pm 0.1 $ $ \end{document}. table 1 collects the calculated fluorescence decay time data , , and the preexponential factors , a , describing the contribution of the i - th fluorescence decay component of the total emission . this results point that the luminescent solution of eaadcy in thf established a spectroscopic inhomogeneous system attributed to the emission from locally excited , s1 ( le ) , and intramolecular charge transfer , s1 ( ict ) , states . for all studied excitation wavelengths ( 370 nm , 390 nm , 400 nm , 420 nm ) emission decay exhibits fast ( lw 0.22 ns ) and slow ( sw 5.7 ns ) decay components . the slow decay component originated from the emission of locally excited state ( perpendicular conformer ) , whereas the fast decay component results from an ensemble of spatial conformers possessing the ict structure ( flattened conformer ) . it is important to note here that the relative amplitude of le and ict emissions strongly depend on the excitation wavelength . the preexponential factor asw ( describing the contribution of the le fluorescence decay component of the total emission ) decreases with increasing excitation wavelength from 78% for excitation at 370 nm to 43% for excitation at 420 nm . in contrast , as the excitation wavelength is increased from 370 nm to 420 nm , the alw increases from 22% to 57% . to test whether the changes in the absorption , fluorescence excitation and fluorescence spectra originate from the solute conformers possesing different angles between their interatomic planes of the donor and acceptor moieties , a series of conformational semiempirical quantum mechanical calculations were carried out . we found that for eaadcy molecule the ground - state rotational potential is essentially flat ( in the range from 60 to 120 ) [ 18 , 19 ] . figure 1a shows the calculated ground - state ( s0 ) rotational potential and the corresponding rotamer distribution function n( ) determined from boltzmann s low at 298 k , for the molecule under study . according to the boltzmann s low , in the ground state about 33% of the all eaadcy molecules possess twist angle between two fragments ( donor and acceptor ) in the range from 60 to 120. thus , quantum - chemical calculations suggest the presence of various conformers in the ground state which have different geometry and absorb at different wavelengths . in addition , it should be noted that eq ( obtained using quantum - chemical calculations ) does not differ from the mean twisting angle \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ < { \varphi_n } > = \int\limits_0^{180 } { \varphi \;n\left ( \varphi \right ) } \,d\varphi $ $ \end{document } , which is convoluted with the distribution function n( ) , and equals \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ { \varphi_{eq } } = < { \varphi_n } > \cong { 90^\circ } $ $ \end{document}. as it was mentioned earlier , the range of inhomogeneous broadening depends on the values of dipole moments of the dye molecules in the ground and excited states . from the quantum - chemical calculations [ 18 , 19 ] ( see fig . 1b ) it is evident that dipole moment of eaadcy in the ground state shows a very week dependence on the dihedral angle , whereas in the first excited state planar molecule possesses five times greater dipole moment than that with perpendicular donor - acceptor arrangement ( i.e. , 15.6 d versus 3.0 d ) . the large differences between \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ { \mu_{{s_1}}}\left ( { le } \right ) $ $ \end{document } and \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ { \mu_{{s_1}}}\left ( { ict } \right ) $ $ \end{document } suggest existence of molecules possessing different solvation shell and different strength of the reaction field r. figure 2a presents the observation - wavelength dependence of fluorescence excitation spectra ( maxima position and shape of the spectra ) of eaadcy in thf at room temperature . the major observation that can be made suggests the strong dependence of the fluorescence excitation spectrum on the observation wavelength . the long - wavelength fluorescence excitation band of eaadcy are composed of at least two bands , centered at about 360 nm and 430 nm . as it was shown in fig . 2a , upon increasing the observation wavelength the intensity of the short - wavelength band at 360 nm decreases . this behavior is accompanied by an increase of the long - wavelength band centered at 430 nm . it is important to note here that each of the area under the fluorescence excitation and fluorescence ( fig . 2a and b ) curves were normalized to unity . in this case , each of fluorescence spectrum corresponds to the emission of the same number of emitting eaadcy molecules . 2fluorescence excitation spectra ( a ) and fluorescence spectra of eaadcy in thf at room temperature as a function of obs ( a ) and exc ( b ) fluorescence excitation spectra ( a ) and fluorescence spectra of eaadcy in thf at room temperature as a function of obs ( a ) and exc ( b ) we also carefully examined the excitation - wavelength dependence of fluorescence spectra of eaadcy in thf . we found that upon increasing the excitation wavelength the intensity of short - wavelength fluorescence band decreases . this behavior is accompanied by an increase of the long - wavelength emission band . analyzing the fluorescence excitation ( fig . 2b ) spectra of eaadcy in thf obtained at different observation and excitation wavelengths , it is found that the ratio of the fluorescence intensity of the long - wavelength and short - wavelength fluorescence bands ( iem ( lw)/iem ( sw ) ) strongly depend on the excitation wavelength . a typical excitation- and observation - wavelength dependent behavior 3b ) , when the excitation wavelength is increased from 360 nm to 445 nm , the ratio iem ( lw)/iem ( sw ) increases from ~0.5 to ~8 . it is important to note here that the ratio iem ( lw)/iem ( sw ) is of the solute concentration independent ( with the limit of experimental error ) . 3the ratio iexc(sw)/iexc(lw ) ( a ) and iem(lw)/iem(sw ) ( b ) as a function of obs and exc , respectively the ratio iexc(sw)/iexc(lw ) ( a ) and iem(lw)/iem(sw ) ( b ) as a function of obs and exc , respectively the steady - state fluorescence excitation spectra are also strongly observation - wavelength dependent . as can be seen ( fig . 3a ) the ratio iexc ( sw)/iexc ( lw ) undergoes a significant decrease when increasing the observation wavelength ( e.g. , from ~6.5 ( obs = 480 nm ) to ~0.8 ( obs = 605 nm ) . this observation / excitation wavelength dependence is similar to the typical red - edge effect observed in low - temperature glasses , polymer matrixes , and organized assemblies such as micelles , vesicles , proteins and membranes [ 215 ] . these results , as well as , our previous study [ 10 , 1820 ] indicate that for eaadcy a distribution of spatial conformers ( lie in difference of rotational angles between donor and acceptor moieties ) is always present ( see fig . 1 ) . when the excitation is carried out at the maximum of the absorption band , the conformers having perpendicular or nearly perpendicular geometry ( ~ 90 ) are excited . as the excitation wavelength is shifted to the red , the rotamer with different angles ( 0 < it can be concluded that ict state ( long - wavelength fluorescence band ) may be formed either by further geometrical changes of the normal conformer ( ~ 90 ) in the locally excited state or directly by excitation of flattened conformers . in order to confirm the interpretation of the steady - state measurements data , the time - resolved emission spectra and from them calculated fluorescence decay times of eaadcy in thf were investigated . these measurements were carried out at 5 ns range of streak camera window , what gave us point - to point time resolution of 10.86 ps per point . figure 4 shows the emission spectra of eaadcy in thf at various times after excitation ( exc = 400 nm ) . as can be seen , upon increasing the time after excitation the short - wavelength ( le ) and long - wavelength ( ict ) fluorescence maxima positions are red - shifted . figure 4 clearly shows that a pronounced shift of the sw and lw bands occurs already at very short time after excitation . in order to make it more evident , the temporal behavior of \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tilde{\nu } _ { sw}^{\max } ( t ) $ $ \end{document } and \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tilde{\nu } _ { lw}^{\max } ( t ) $ $ \end{document } 4time - resolved emission spectra of eaadcy in thf at room temperature at various times after excitation ( exc = 400 nm)fig . 5time - dependence of the frequency of the short - wavelength ( sw ) and long - wavelength ( lw ) emission band maximum of eaadcy in thf time - resolved emission spectra of eaadcy in thf at room temperature at various times after excitation ( exc = 400 nm ) time - dependence of the frequency of the short - wavelength ( sw ) and long - wavelength ( lw ) emission band maximum of eaadcy in thf in order to determine the stokes - shift correlation function c(t ) , the time - dependent frequencies \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tilde{\nu } _ { sw}^{\max } ( t ) $ $ \end{document } and \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tilde{\nu } _ { lw}^{\max } ( t ) $ $ \end{document } are normalized according to eq . figure 6 illustrates the resulting c(t ) curves for short - wavelength and long - wavelength fluorescence bands . the decay times ( obtained for different exc ) of c(t ) are summarized in table 1 . analyzing the experimental decay data , it follows that the obtained \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tau_{sw}^l $ $ \end{document } and \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tau_{lw}^l $ $ \end{document } values do not depend on exc . from the \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tau_{sw}^l $ $ \end{document } and \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tau_{lw}^l $ $ \end{document } values obtained for both of the conformers ( perpendicularle form , flattenedict form ) , it is evident that the longitudinal relaxation time is very different . the ratio of the corresponding longitudinal relaxation times \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \frac{{\tau_{sw}^l}}{{\tau_{lw}^l } } $ $ \end{document } is about 3 . this large difference between \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tau_{sw}^l $ $ \end{document } and \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tau_{lw}^l $ $ \end{document } values is understandable taking into account different interactions of the conformers with the reactive electric field of the surrounding solvent . in our previous publication form of eaadcy possesses greater dipole moment in the excited state than in the ground state , while perpendicular ( le ) form of eaadcy possesses lower dipole moment value in the excited state in comparison to its value in the ground state . the following changes of dipole moment were obtained : \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \delta { \mu_{perpen . } } = - { 1}.{82}\,{\hbox{d } } $ $ \end{document } , \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \delta { \mu_{flatt . } } = { 13}.{5}\,{\hbox{d } } $ $ \end{document}. fig . 6decay of the solvent correlation function c(t ) of le ( b ) and ict ( a ) form of eaadcy in thf at room temperaturetable 1the longitudinal relaxation times ( \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tau_{sw}^l $ $ \end{document } , \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tau_{lw}^l $ $ \end{document } ) , fluorescence decay times ( sw , lw ) and preexponential factors ( asw , alw ) of eaadcy in thf\documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tau_{sw}^l\left ( { \hbox{ps } } \right ) $ $ \end{document}\documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tau_{lw}^l\left ( { \hbox{ps } } \right ) $ $ \end{document}sw ( ps)asw ( % ) lw ( ps)alw ( % ) exc = 370 nm162 2053 45.6578.20.2221.81.21exc = 390 nm170 1564 85.8366.40.2133.61.09exc = 400 nm187 2059 55.7353.30.2546.71.18exc = 420 nm182 1262 85.5543.20.2056.81.22 decay of the solvent correlation function c(t ) of le ( b ) and ict ( a ) form of eaadcy in thf at room temperature the longitudinal relaxation times ( \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tau_{sw}^l $ $ \end{document } , \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ \tau_{lw}^l $ $ \end{document } ) , fluorescence decay times ( sw , lw ) and preexponential factors ( asw , alw ) of eaadcy in thf the experimental decay curves were fitted to a multiexponential function \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ f(t ) = \sum\nolimits_{i = 1}^n { { a_i}\exp \left ( { - t/\tau } \right ) } $ $ \end{document } , where ai and i are the preexponential coefficient ( describing the contribution of the i - th fluorescence decay component to the total emission ) and decay time of the i - th component , respectively . the average value of , describing the goodness of the fitting procedure for all decay curves , i.e. , one- and two - exponential fitting , equals \documentclass[12pt]{minimal } \usepackage{amsmath } \usepackage{wasysym } \usepackage{amsfonts } \usepackage{amssymb } \usepackage{amsbsy } \usepackage{mathrsfs } \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt } \begin{document}$$ { \chi^2 } = 1.2\pm 0.1 $ $ \end{document}. table 1 collects the calculated fluorescence decay time data , , and the preexponential factors , a , describing the contribution of the i - th fluorescence decay component of the total emission . this results point that the luminescent solution of eaadcy in thf established a spectroscopic inhomogeneous system attributed to the emission from locally excited , s1 ( le ) , and intramolecular charge transfer , s1 ( ict ) , states . for all studied excitation wavelengths ( 370 nm , 390 nm , 400 nm , 420 nm ) emission decay exhibits fast ( lw 0.22 ns ) and slow ( sw 5.7 ns ) decay components . the slow decay component originated from the emission of locally excited state ( perpendicular conformer ) , whereas the fast decay component results from an ensemble of spatial conformers possessing the ict structure ( flattened conformer ) . it is important to note here that the relative amplitude of le and ict emissions strongly depend on the excitation wavelength . the preexponential factor asw ( describing the contribution of the le fluorescence decay component of the total emission ) decreases with increasing excitation wavelength from 78% for excitation at 370 nm to 43% for excitation at 420 nm . in contrast , as the excitation wavelength is increased from 370 nm to 420 nm , the alw increases from 22% to 57% . analyzing the data obtained from the steady - state , time - resolved measurements and quantum - chemical calculations one can state that : at room temperature , eaadcy exists as an equilibrium mixture of various conformers having different geometry ( in the range from 60 to 120 ) and absorb at different wavelengths . as the excitation wavelength is changed , a slightly different species are excited.the ratio of the fluorescence intensity of the long - wavelength and short - wavelength fluorescence bands strongly depends on the observation / excitation wavelength , whereas the wavelengths of the fluorescence excitation and fluorescence bands maxima are independent on the observation / excitation wavelengths in accordance to the kasha rule.the difference between stokes shift in the le and ict states was attributed to the solvent response to the large photoinduced dipole moment of eaadcy in the fluorescent charge transfer state.the excitation wavelength dependent biexponential decay times ( and preexponential factors asw and alw ) of eaadcy in thf lead us to conclude that ict state really may be formed either by further geometrical changes of the locally excited conformer or directly by excitation of flattened conformers . at room temperature , eaadcy exists as an equilibrium mixture of various conformers having different geometry ( in the range from 60 to 120 ) and absorb at different wavelengths . the ratio of the fluorescence intensity of the long - wavelength and short - wavelength fluorescence bands strongly depends on the observation / excitation wavelength , whereas the wavelengths of the fluorescence excitation and fluorescence bands maxima are independent on the observation / excitation wavelengths in accordance to the kasha rule . the difference between stokes shift in the le and ict states was attributed to the solvent response to the large photoinduced dipole moment of eaadcy in the fluorescent charge transfer state . the excitation wavelength dependent biexponential decay times ( and preexponential factors asw and alw ) of eaadcy in thf lead us to conclude that ict state really may be formed either by further geometrical changes of the locally excited conformer or directly by excitation of flattened conformers . Output:	the excitation wavelength dependence of the steady - state and time - resolved emission spectra of ethyl 5-(4-aminophenyl)-3-amino-2,4-dicyanobenzoate ( eaadcy ) in tetrahydrofuran ( thf ) at room temperature has been examined . it is found that the ratio of the fluorescence intensity of the long - wavelength and short - wavelength fluorescence bands strongly depends on the excitation wavelength , whereas the wavelengths of the fluorescence excitation and fluorescence bands maxima are independent on the observation / excitation wavelengths . the dynamic stokes shift of fluorophore in locally excited ( le ) and intramolecular charge transfer ( ict ) states has been studied with a time resolution about 30 ps . the difference between stokes shift in the le and ict states was attributed to the solvent response to the large photoinduced dipole moment of eaadcy in the fluorescent charge transfer state . on this base we can state that , the relaxation of the polar solvent molecules around the fluorophore was observed .
PubmedSumm118847	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: all metathesis reactions were performed under an n2 atmosphere . solvents , e.g. ch2cl2 and benzene , were purified and dried in a glasscontour solvent push - still system . deuterated solvents for all ring - opening reactions were degassed and filtered through basic alumina before use . [ ( h2imes)(pcy3)(cl)2ru = chph ] and ethyl 1-bromocyclobutane carboxylate were purchased from aldrich . the synthesis of grubbs iii catalyst , [ ( h2imes)(3-br - pyr)2cl2ru = chph ] , was performed according to the procedure of love et al . a fresh stock solution of the grubbs iii catalyst ( 0.02 m for aromp or 0.03 m for rom , arom-1 , and arom-2 ) and fresh stock solutions of monomers 3 and 4 ( 0.171.0 m for aromp , depending on the desired length , or 0.03 m for rom , arom-1 , and arom-2 ) were prepared in cd2cl2 for each of the nmr experiments . mallinckrodt silica gel 60 ( 230400 mesh ) was used for column chromatography . analytical thin layer chromatography ( tlc ) was performed on precoated silica gel plates ( 60f254 ) , chromatography on silica gel-60 ( 230400 mesh ) , and combi - flash chromatography on redisep normal phase silica columns ( silica gel-60 , 230400 mesh ) . varian inova400 , inova500 , inova600 and bruker nanobay 400 , avance iii 500 , avance iii 700 , avance iii - hd 850 mhz nmr instruments were used for analysis . chemical shifts are denoted in ppm ( ) and calibrated from residual undeuterated solvents . the degree of polymerization ( dp ) of linear polymers was assessed by comparing the h nmr integration of the polymer alkene protons to that of the phenyl end group . molecular weights and molar mass dispersities were measured with a gel phase chromatography system constructed from a shimadzu pump coupled to a shimadzu uv detector . ch2cl2 served as the eluent with a flow rate of 0.700 ml / min on an american polymer standards column ( phenogel 5 mxl gpc column , phenomenex ) . a modification of the two - step procedure of elsheimer was followed.safety warning : cf2br2 has a very low boiling point , and addition of cf2br2 to norbornene is very exothermic . therefore , for a large - scale reaction , this procedure should be carried out carefully behind a safety shield . to a mixture of norbornene ( 6.10 g , 65 mmol ) , cucl ( 0.99 g , 1 mmol ) , ethanolamine ( 3.00 g , 50 mmol ) , and tert - butyl alcohol ( 7.40 g , 100 mmol ) in a 50 ml flask , cf2br2 was slowly added ( 27.30 g , 130 mmol ) . the resulting mixture was protected from light and stirred at reflux ( 8085 c ) for 48 h. then it was cooled and diluted with deionized water ( 50 ml ) and et2o ( 25 ml ) . the et2o layer was washed with h2o ( 5 25 ml ) and dried over anhydrous na2so4 . after filtration , the extract was concentrated and the residue was purified by flash column chromatography to yield a mixture of bicyclo[2.2.1]heptanes as a colorless oil ( 16.75 g , 87% ) . h nmr ( 500 mhz , cdcl3 ) : 4.09 ( d , j = 10 hz , 1h ) , 2.78 ( td , j = 15 hz , 10 hz , 1h ) , 2.71 ( s , 1h ) , 2.68 ( d , j = 10 hz , 1h ) , 2.12 ( d , j = 10 hz , 1h ) , 1.76 ( m , 1h ) , 1.64 ( m , 1h ) , 1.401.20 ( m , 3h ) . in a screw - top vial under an n2 atmosphere , koh ( 5.89 g , 10.5 mmol ) was dissolved in deionized h2o ( 4 ml ) . a sample of 2-bromo-3-(bromodifluoromethyl)bicyclo[2.2.1]heptanes ( 0.776 g , 2.66 mmol ) was added to the solution , and the mixture was heated at 130 c in a microwave reactor at 20 bar for 2 h. then the solution was cooled and washed with chcl3 ( 2 4 ml ) , and the ph of the basic extract was adjusted to 2 with 3 n aqueous hcl . the aqueous solution was extracted with chcl3 ( 3 4 ml ) , and the combined chcl3 solution was dried over anhydrous na2so4 and concentrated in vacuo to give a brown oil . purification by flash column chromatography ( 95:5/ch2cl2:meoh ) yielded bicyclo[2.2.1]hept-2-ene-2-carboxylic acid as a colorless oil ( 160 mg , 50% ) . bicyclo[2.2.1]hept-2-ene-2-carboxylic acid ( 40 mg , 0.29 mmol ) was treated with n , n - diisopropyl - o - methylisourea ( 180 mg , 1.16 mmol ) in dry ether ( 5 ml ) and stirred for 48 h. the urea byproduct precipitated at 20 c , and it was removed by filtration . removal of the solvent afforded a yellow oil which was purified by flash column chromatography ( 90:10/hexane : ch2cl2 ) to yield ester 2 ( 26 mg , 58% ) . h nmr ( 400 mhz , cd2cl2 ) : 6.91 ( d , j = 2.8 hz , 1h ) , 3.72 ( s , 3h ) , 3.26 ( s , 1h ) , 3.02 ( s , 1h ) , 1.75 ( m , 2h ) , 1.48 ( d , j = 8.4 hz , 1h ) , 1.20 ( d , j = 8.4 hz , 1h ) . c nmr ( 100 mhz , cdcl3 ) : 164.9 , 146.6 , 140.5 , 51.0 , 48.0 , 43.4 , 41.8 , 24.5 , 24.4 . these monomers were prepared according to snider s approach ; the purification of monomer 4 was modified as noted . to a 50 ml flask with anhydrous alcl3 powder under an n2 atmosphere the reaction mixture was cooled in an ice bath and quenched with saturated nh4cl solution . the precipitate was removed by filtering the resulting mixture through a pad of celite . the filtrate was extracted with three portions of et2o , and the combined et2o extract was washed with brine and dried over anhydrous mgso4 . the solvent was removed in vacuo , and the crude product was subjected to flash column chromatography . alcl3 ( 160 mg , 1.21 mmol , 0.5 equiv ) , methyl propiolate ( 204 mg , 2.42 mmol ) , and cyclopentene ( 170 l , 2.90 mmol , 1.2 equiv ) were stirred for 7 days in dry benzene ( 50 ml ) . flash column chromatography of the crude product ( 30:70/hexane : ch2cl2 ) yielded ester 3 ( 175 mg , 48% yield ) . h nmr ( 400 mhz , acetone - d6 ) : 6.62 ( br s , 1h ) , 3.69 ( s , 3h ) , 3.33 ( br dd , j = 3.2 hz , 7.6 hz , 1h ) , 3.06 ( br dd , j = 3.6 hz , 8.0 hz , 1h ) , 1.781.21 ( m , 6h ) . c nmr ( 100 mhz , cdcl3 ) : 162.5 , 147.5 , 138.2 , 51.1 , 46.9 , 44.5 , 25.5 , 25.4 , 22.9 . alcl3 ( 227 mg , 1.72 mmol , 0.86 equiv ) , methyl propiolate ( 168 mg , 2.00 mmol ) , and cyclohexene ( 263 l , 2.60 mmol , 1.30 equiv ) were stirred for 7 days in dry benzene ( 5 ml ) and yielded a mixture of compound 4 and isomer methyl ( e)-3-(cyclohex-1-enyl)propenoate in a ratio of 1:0.110.23 . the mixture was treated with m - chloroperoxybenzoic acid ( m - cpba ) to epoxidize the isomeric byproduct , followed by flash column chromatography ( 30:70/hexane : ch2cl2 ) to provide bicyclic ester 4 ( 210 mg , 65% yield ) . h nmr ( 400 mhz , acetone - d6 ) : 6.89 ( d , j = 1.2 hz , 1h ) , 3.71 ( s , 3h ) , 3.073.04 ( m , 1h ) , 2.802.77 ( m , 1h ) , 2.001.30 ( m , 8h ) . c nmr ( 100 mhz , cdcl3 ) : 162.4 , 150.1 , 141.4 , 50.7 , 39.8 , 38.1 , 23.5 , 23.3 , 18.6 , 18.0 . alcl3 ( 1.00 g , 7.56 mmol , 0.5 equiv ) , methyl propiolate ( 1.27 g , 15.2 mmol ) , and cycloheptene ( 2.16 ml , 18.2 mmol , 1.2 equiv ) were stirred for 7 days in dry benzene ( 50 ml ) . flash column chromatography of the crude product ( 30:70/hexane : ch2cl2 ) yielded 5 ( 1.40 g , 50% yield ) . h nmr ( 400 mhz , cdcl3 ) : 6.70 ( d , j = 1 hz , 1h ) , 3.61 ( s , 3h ) , 2.99 ( m , 1h ) , 2.77 ( m , 1h ) , 1.771.21 ( m , 10h ) . c nmr ( 100 mhz , cdcl3 ) : 162.6 , 148.9 , 140.5 , 50.6 , 46.9 , 45.4 , 31.6 , 29.1 , 28.6 , 27.9 , 27.7 . all kinetic experiments were performed at least twice , and preparative polymerization experiments were performed three times . under an n2 atmosphere , a solution of monomer a ( cyclobutene derivative ) in cd2cl2 ( 300 l ) was added to the nmr tube . then 300 l of grubbs iii stock solution ( c = 0.02 m ) was added to the nmr tube . after complete mixing of the solution , nmr spectra were acquired at 25 c until the catalyst had reacted with monomer a as determined by the disappearance of its alkylidene proton signal . after no further propagation occurred , the reaction was quenched with ethyl vinyl ether and stirred for 1 h. solvent was evaporated , and polymer was purified by chromatography over silica gel ( 97:3/ch2cl2:acetone ) . yield was determined by assuming 100% conversion of monomer a. monomer 2 ( 8.3 mg , 60 mol , 10 equiv ) and grubbs iii catalyst ( 5.3 mg , 6.0 mol , 1 equiv ) were mixed in cd2cl2 . the reaction was followed by h nmr spectroscopy at 25 c for 5 h before the temperature was elevated to 50 c . cyclohexene 6 ( 12 l , 120 mol , 20 equiv ) was added . no change in the alkylidene peak of the catalyst was observed within 300 min . monomer 3 ( 23.8 mg , 150 mol , 25 equiv ) and grubbs iii catalyst ( 5.3 mg , 6.0 mol , 1 equiv ) were mixed . cyclohexene 6 ( 24.5 mg , 30 l , 50 equiv ) was added 30 min later . flash column chromatography ( 97:3/ch2cl2:acetone ) of the crude product yielded poly(3-alt-6)13 ( 15 mg , 43% ) . h nmr ( 600 mhz , cd2cl2 ) : 7.357.14 ( m , 5h ) , 6.60 ( m , 13h ) , 5.32 ( m , 27h ) , 3.683.60 ( m , 54h ) , 3.203.10 ( m , 14h ) , 2.02.3 ( m , 10h ) , 2.601.00 ( m , 267h ) . monomer 3 ( 9.5 mg , 50 mol , 10 equiv ) and grubbs iii catalyst ( 5.3 mg , 6.0 mol , 1 equiv ) were mixed . cyclohexene 6-d10 ( 9.8 mg , 12 l , 20 equiv ) was added 30 min later . the crude product was purified by flash column chromatography ( 97:3/ch2cl2:acetone ) to yield poly(3-alt-6-d10)6 ( 4.8 mg , 40% ) . h nmr ( 600 mhz , cd2cl2 ) : 7.357.14 ( m , 5h ) , 7.02 ( dd , j = 8.1 , 5.7 hz , 1h ) , 5.32 ( m , 6h ) , 3.683.60 ( m , 22h ) , 3.201.00 ( m , 80h ) . alternating ring - opening polymerization of monomer 4 and 6 was carried out at different temperatures ranging from 25 to 60 c to optimize reaction conditions . monomer 4 ( 19.9 mg , 120 mol , 20 equiv ) and grubbs iii catalyst ( 5.3 mg , 6.0 mol , 1 equiv ) were mixed in cd2cl2 . cyclohexene 6 ( 19.7 mg , 24 l , 40 equiv ) was added after 50 min . the nmr tube was spun for 8 h at 25 c to reach 90% consumption of monomer 4 . the crude product was subjected to flash column chromatography ( 97:3/ch2cl2:acetone ) to yield poly(4-alt-6)16 ( 16 mg , 53% ) . h nmr ( 600 mhz , cd2cl2 ) : 7.357.14 ( m , 5h ) , 6.52 ( m , 16h ) , 5.79 ( m , 15h ) , 5.31 ( m , 26h ) , 3.693.59 ( m , 45h ) , 2.60 ( m , 23h ) , 2.25 ( m , 60h ) , 2.001.22 ( m , 266h ) . c nmr ( 100 mhz , cdcl3 ) : 169.4 , 142.4 , 141.9 , 136.3 , 131.2 , 130.7 , 130.6 , 130.4 , 130.2 , 130.2 , 130.0 , 129.1 , 128.4 , 51.5 , 51.5 , 51.4 , 43.9 , 42.8 , 37.3 , 28.7 , 28.1 , 21.8 , 21.7 . monomer 4 ( 19.9 mg , 120 mol , 20 equiv ) and grubbs iii catalyst ( 5.3 mg , 6.0 mol , 1 equiv ) were mixed in cd2cl2 , and cyclohexene 6 ( 19.7 mg , 24.2 l , 40 equiv ) was added after 50 min . the nmr tube was spun for 6 h at 35 c to reach > 95% consumption of monomer 4 . the crude product was subjected to flash column chromatography ( 97:3/ch2cl2:acetone ) to yield poly(4-alt-6)16 ( 20 mg , 65% ) . h nmr ( 600 mhz , cdcl3 ) : 7.357.14 ( m , 6h ) , 6.52 ( m , 16h ) , 5.79 ( m , 15h ) , 5.50 ( m , 1h ) , 5.31 ( m , 17h ) , 3.693.59 ( m , 47h ) , 2.78 ( m , 23h ) , 2.10 ( m , 64h ) , 1.981.20 ( m , 263h ) . monomer 4 ( 19.9 mg , 120 mol , 20 equiv ) and grubbs iii catalyst ( 5.3 mg , 6.0 mol , 1 equiv ) were mixed in cd2cl2 . after 50 min , cyclohexene - d106-d10 ( 19.7 mg , 24.2 l , 40 equiv ) was added . the product was purified by flash column chromatography ( 97:3/ch2cl2:acetone ) to yield poly(4-alt-6-d10)15 ( 18 mg , 60% ) . h nmr ( 600 mhz , cd2cl2 ) : 7.357.4 ( m , 5h ) , 5.78 ( m , 15h ) , 5.42 ( m , 2h ) , 3.703.60 ( m , 45h ) , 2.82 ( m , 23h ) , 2.25 ( m , 27h ) , 1.781.20 ( m , 164h ) . monomer 4 ( 49.7 mg , 300 mol , 50 equiv ) and grubbs iii catalyst ( 5.3 mg , 6.0 mol , 1 equiv ) were mixed in cd2cl2 , and cyclohexene 6 ( 49.2 mg , 60.6 l , 100 equiv ) was added after 30 min . the nmr tube was spun for 6 h at 35 c to reach 68% conversion of monomer 4 . partial h nmr of crude poly(4-alt-6)34 ( 600 mhz , cd2cl2 ) : 7.357.14 ( m , 5h ) , 6.89 ( d , j = 1.2 hz , 8h ) , 6.50 ( m , 34h ) , 5.79 ( m , 32h ) , 5.28 ( m , 41h ) , 3.703.60 ( m , 150h ) , 3.073.04 ( m , 10h ) . ( partial h nmr spectroscopic data are reported due to incomplete polymerization and significant upfield overlap of 4 and 6 with the new peaks from the polymer . ) monomer 4 ( 49.7 mg , 300 mol , 50 equiv ) and grubbs iii catalyst ( 5.3 mg , 6.0 mol , 1 equiv ) were mixed in cd2cl2 . after 30 min , cyclohexene 6 ( 49.2 mg , 60.6 l , 100 equiv ) was added . the nmr tube was spun for 2 h at 60 c to reach 72% conversion of monomer 4 . the product was purified by flash column chromatography ( 97:3/ch2cl2:acetone ) to yield poly(4-alt-6)36 ( 36 mg , 65% ) . h nmr ( 600 mhz , cd2cl2 ) : 7.357.14 ( m , 5h ) , 6.50 ( m , 36h ) , 5.79 ( m , 34h ) , 5.28 ( m , 55h ) , 3.703.60 ( m , 129h ) , 2.75 ( m , 53h ) , 2.302.10 ( m , 142h ) , 1.951.20 ( m , 589h ) . monomer 5 ( 54.8 mg , 300 mol , 50 equiv ) and grubbs iii catalyst ( 5.30 mg , 6.00 mol , 1 equiv ) were mixed in cd2cl2 , and cyclohexene 6 ( 49.0 mg , 60 l , 100 equiv ) was added after 50 min . the nmr tube was spun for 72 h at 35 c until no further propagation was observed by h nmr spectroscopy . the crude product was subjected to flash column chromatography ( 97:3/ch2cl2:acetone ) to yield poly(5-alt-6)10 ( 11 mg , 14% ) . h nmr ( 600 mhz , cd2cl2 ) : 7.357.12 ( m , 5h ) , 6.58 ( m , 10h ) , 5.42 ( m , 19h ) , 5.28 ( m , 10h ) , 3.703.60 ( m , 36h ) , 3.103.00 ( m , 10h ) , 2.771.95 ( m , 254h ) . under an n2 atmosphere , a solution of monomer a ( cyclobutene derivative , 1 , 3 , 4 , or 5 , [ a ] = 0.03 m ) in cd2cl2 ( 300 l ) was added to an nmr tube . then 300 l of the stock solution of grubbs iii catalyst ( c = 0.03 m ) was added to the nmr tube . after complete mixing of the solution , the reaction was closely monitored by h nmr or c nmr spectroscopy . a solution of monomer a ( 3 or 4 , [ a ] = 0.03 m ) in cd2cl2 ( 300 l , 18.86 mol ) was added to an nmr tube that had been flushed with n2 . then 300 l of the stock solution of grubbs iii catalyst ( c = 0.03 m ) was added to the nmr tube . after complete mixing of the solution , the reaction was followed by h nmr or c nmr spectroscopy until > 90% of the catalyst ( 1012 h ) was consumed as determined by disappearance of the ru alkylidene proton or carbon resonance of the grubbs iii catalyst at 19.1 or 316.1 ppm . then cyclohexene 6 was added in 10-fold excess , and the reaction was monitored until the ru alkylidene proton resonance at 19.0 ppm disappeared . the reaction was terminated with ethyl vinyl ether , and the crude mixture was subjected to silica chromatography ( 100% ch2cl2 ) . for the products of the 36 arom-1 experiment , partially purified fractions were characterized by mass spectrometry , h nmr , c nmr , and hsqc spectroscopy ( supporting information ) . h nmr ( 850 mhz , cd2cl2 ) : 7.53 ( dd , j = 8.1 , 0.9 hz , 2h ) , 7.36 ( t , j = 7.7 hz , 2h ) , 7.287.23 ( m , 2h ) , 7.13 ( s , 1h ) . c nmr ( 214 mhz , cd2cl2 ) : 137.9 , 129.2 , 129.1 , 128.2 , 127.0 . a solution of monomer a ( 3 or 4 , [ a ] = 0.03 m ) in cd2cl2 ( 300 l , 18.86 mol ) was added to an nmr tube that had been flushed with n2 . then 300 l of the stock solution of grubbs iii catalyst ( c = 0.03 m ) was added to the nmr tube . after complete mixing of the solution , the reaction was followed by h nmr spectroscopy until > 90% of the catalyst ( 1012 h ) was consumed as determined by disappearance of the ru alkylidene proton of the grubbs iii catalyst at 19.1 ppm ; then cyclohexene 6 was added in 10-fold excess . generation of [ ru]-b - a was monitored by the appearance of a multiplet resonance at 19.0 ppm . when the formation of [ ru]-b - a was complete as judged by the integrated intensity of the resonance , 1 equiv of monomer a was added to form [ ru]-a-b - a and then [ ru]-b - a-b - a . the reaction was monitored until the ru alkylidene proton resonance at 19.0 ppm disappeared or the intensity was constant . we noted that using grubbs iii catalyst for the incorporation of a ring into the propagating chain backbone limits backbiting in the case of the well - investigated norbornene romp . therefore , we decided to examine norbornene ester 2 as a partner for cyclohexene in aromp . we prepared monomer 2 by a modification of the method of elsheimer ( see experimental methods ) . however , when we subjected monomer 2 to aromp conditions with cyclohexene 6 , we observed no polymerization . furthermore , when the catalyst was mixed with monomer 2 , no ring - opened product was observed at all . we attributed the loss of romp activity of monomer 2 to the steric hindrance posed by the combination of the bridging methylene group and the ester . we next tested bicyclic monomers 35 , designed for their ring strain and lower steric hindrance around the alkenes ( figure 1 ) . these monomers were prepared by lewis acid catalyzed [ 2 + 2 ] cycloaddition according to snider s approach . for practicality , we developed a simplified purification procedure for monomer 4 to remove the isomeric byproduct ( see experimental methods ) . first , we undertook kinetic monitoring of the initial ring - opening metathesis ( rom ) reactions for each of these monomers by h nmr spectroscopy ( figure 2 ) . in each of the experiments , an equimolar amount of monomer a ( the bicycloalkene ester ) and grubbs iii catalyst was mixed in cd2cl2 . the disappearance of the alkylidene signal of the catalyst at 19.1 ppm was followed by h nmr spectroscopy ; the signal was integrated relative to the methyl ester signals between 3.8 and 3.5 ppm . under the conditions of the experiment , 50% of monomer 3 was ring opened in 25 min , whereas 50% of monomer 1 was ring - opened in 40 min . under the same conditions , monomer 4 underwent 50% ring - opening in 100 min and monomer 5 required 300 min for 50% ring - opening . thus , upon addition of grubbs iii catalyst , monomer 3 has the fastest ring - opening rate , in accordance with the predicted ring strains . monomer and grubbs iii catalyst were mixed in a 1:1 ratio , [ a ] = [ grubbs iii ] = 0.03 m. percent conversion was determined by h nmr spectroscopy and integration of the ru alkylidene proton resonance relative to the methyl ester resonances ( supporting information ) . t1/2 were obtained from the plot , monomer 1 : t1/2 = 40 min , monomer 3 : t1/2 = 25 min , monomer 4 : t1/2 = 100 min ; monomer 5 : t1/2 = 300 min . each experiment was performed at least twice , and data from representative experiments are shown . when subjected to grubbs iii catalyst in the absence of cyclohexene 6 , each of the three bicyclic monomers 3 , 4 , and 5 underwent ring - opening ; however , no polymerization could be detected . thus , we established that these monomers are suitable for the preparation of alternating copolymers because their rates of homopolymerization are zero . all three monomers produced copolymers with cyclohexene 6 in the presence of grubbs iii catalyst . the rates of polymerization varied substantially , and all were slower than the rate of aromp between cyclobutene ester 1 and cyclohexene 6 as determined by h nmr spectroscopy ( table 1 ) . lengths of polymers were determined by integration of alkene proton peaks ( h1 , h3 , and h4 , figure 3 ) relative to that of the phenyl end group in the h nmr spectrum . copolymerization of monomer 3 or 5 with 6 yielded much shorter polymers than did that of monomer 4 with 6 under the same conditions ( table 1 ) . alternating ring - opening metathesis polymerization ( aromp ) of monomers 4 and 6 . the region of h nmr spectra in which backbone olefinic hydrogen resonances of poly(4-alt-6)n appear is shown . ( b ) polymer product prepared from cyclohexene - d10 and dissolved in cd2cl2 . poly(4-alt-6-d10)n was dissolved in cd2cl2 instead of cdcl3 to allow accurate integration of the phenyl resonances . percent conversion determined by integration of h nmr spectra of monomer a unless specified otherwise . dp[ab ] was determined by h nmr spectroscopy with integration relative to the phenyl end group and represents the average numbers of ab dyads incorporated in linear copolymers . % conv could not be determined by h nmr spectroscopy due to overlap of alkene and polymer peaks . furthermore , the h nmr spectrum of each of the polymers is consistent with an alternating backbone structure ( supporting information ) in which the olefin bearing a carbomethoxy substituent has an e configuration . for example , in the spectrum of poly(4-alt-6)13 , the proton resonance for the carbomethoxy - substituted olefin ( h1 ) , which is derived from cyclohexene 6 , has an integration identical to that of the h3 alkene resonance at 5.8 ppm which is derived from monomer 4 ( figure 3a ) . likewise , the analogous proton resonances in poly(3-alt-6)n and poly(5-alt-6)n have nearly identical integration values . moreover , characterization of poly(4-alt-6)n by hsqc spectroscopy confirmed that the carbomethoxy - substituted olefin is a single stereoisomer ; there is a single h1 signal at 6.5 ppm that correlates with c1 ( supporting information ) . comparison of model compound chemical shifts with the h1 alkene chemical shift further confirmed that the e configuration was obtained . further evidence for the alternating structure was obtained for the poly(4-alt-6)n copolymers by experiments with cyclohexene - d10 , 6-d10 . h nmr analysis of the deuterium - labeled copolymer poly(4-alt-6-d10)n indicates a complete loss of the carbomethoxy - substituted olefin ( h1 ) resonance at 6.5 ppm and the h4 alkene resonance at 5.3 ppm ( figure 3b ) . complete loss of the h1 and h4 resonances upon deuteration is consistent with a rigorously alternating ab linear scaffold . their loss indicates the absence of aa dyads that can form upon backbiting during the aromp . likewise , in the experiments with deuterated cyclohexene , the integrated ratio of h3 versus the methyl ester remains at 1:3 , suggesting that no bb dyad is formed . therefore , introduction of a cyclohexyl ring fused to the cyclobutene ester monomer provides access to linear , alternating copolymers . however , at the same concentrations and monomer / catalyst ratios , monomers 3 and 5 both generated shorter polymers than did monomer 4 ( table 1 ) . reaction conditions for poly(4-alt-6)n were examined , and the best yield was obtained in ch2cl2 , at temperatures between 35 and 60 c . the gpc elution profile of poly(4-alt-6)n displayed a monomodal molecular weight distribution ( supporting information ) . this distribution is consistent with the absence of cyclic polymer . likewise , the dispersity ( dm = 2.0 0.1 ) of poly(4-alt-6)n was significantly smaller than that of the previously reported poly(1-alt-6)n ( dm = 5 ) , which displayed a bimodal molecular weight distribution . the molecular weight profile is consistent with the absence of intramolecular chain transfer for the aromp of monomer 4 and cyclohexene . monomer 3 was selected for comparison with monomer 4 in order to study how their structures affect the initiation and propagation rates and the extents of polymerization . to preclude the possibility that impurities in monomer 3 inherited from synthesis ( see experimental methods ) deactivated the catalyst , monomer 3 this sample was utilized in aromp and compared with monomer 3 synthesized otherwise . no difference in activity or polymer length was observed . then we undertook kinetic monitoring of arom-1 ( formation of ba dimer ) with monomers 3 or 4 and cyclohexene 6 by c nmr spectroscopy . in both reactions , we observed formation of [ ru]-a upon addition of the a monomer to grubbs iii catalyst ( figure 4 , [ ru ] + 3 and [ ru ] + 4 ) and disappearance of ru catalyst . in the case of [ ru]-4 , the formation of a single ru carbene ( 314.5 ppm ) was observed . addition of cyclohexene cleanly yielded [ ru]-6 - 4 ( 338.0 ppm , figure 4 , 6 + [ ru]-4 ) in 1.5 h , and there was no further change in the nmr spectrum over 30 h. alternating ring - opening metathesis ( arom-1 ) of monomers 3 and 6 and monomers 4 and 6 . the carbene regions of c nmr spectra of ( 3-alt-6)1 ( left ) and ( 4-alt-6)1 ( right ) are shown . in the top spectra , [ ru ] catalyst was mixed with 3 or 4 in cd2cl2 for 1012 h. cyclohexene was added after > 90% of ru catalyst was consumed . the 6 + [ ru]-3 reaction was monitored for 300 min , and 6 + [ ru]-4 reaction was monitored for 30 h. the c nmr spectrum of 6 + [ ru]-3 was acquired 3050 min after addition of cyclohexene , and the c nmr spectrum of 6 + [ ru]-4 was acquired 5070 min after addition of cyclohexene . each experiment was performed at least twice , and data from representative experiments are shown . in the case of [ ru]-3 , after the addition of cyclohexene , we observed regeneration of the grubbs iii catalyst ( 316.1 ppm ) in addition to the [ ru]-6 - 3 carbene ( 337.8 ppm , figure 4 , 6 + [ ru]-3 ) during the first 2 h of reaction . within 5 h of cyclohexene addition , both the [ ru]-6 - 3 and ru catalyst carbene resonances disappeared , and no new carbene resonances appeared . we analyzed products of the arom-1 reaction and obtained ph-(3-alt-6)1-ph , e - stilbene , and cyc-(3-alt-6)1 ( scheme 1a ) . hence , backbiting or cross - metathesis can occur very early in the reaction . an independent experiment in which ru catalyst was mixed with monomer 3 for 18 h showed that [ ru]-3 remains intact . thus , the ru enoic carbene is not reactive with itself , and side reactions must occur after cyclohexene addition . formation of stilbene suggests that if the desired propagation pathway is kinetically less favorable , the ru alkylidene ( [ ru]-6 - 3 ) species undergoes cross - metathesis in an intra- or intermolecular reaction with the styrene end group . in contrast , no regeneration of grubbs iii catalyst was observed in the ( 4-alt-6)1 experiment ( figure 4 , 6 + [ ru]-4 ) . the [ ru]-6 - 4 carbene remained stable for 2 days under the reaction conditions . this result is consistent with our observations that monomer 4 provides a longer and backbiting - free linear alternating copolymer via aromp . carbenes ( circled ) were monitored by c nmr spectroscopy ( figure 4 ) . we also carried out double arom ( arom-2 ) experiments with monomers 3 and 4 to compare their behavior in systems with longer chains ( scheme 1 and figure 5 ) . in these experiments , we mixed monomer a and catalyst in a 1:1 ratio in an nmr tube to form [ ru]-a , and we monitored the reactions by h nmr spectroscopy . the mixtures were allowed to react for 1012 h to ensure nearly complete conversion to [ ru]-a ( the benzylidene proton signal at 19.1 ppm was reduced to less than 10% of its original intensity ) . at this time , 10 equiv of cyclohexene ( monomer b ) was added to generate [ ru]-b - a ( figure 5 ) . the formation of [ ru]-b - a was monitored by the appearance of a new multiplet resonance at 19.0 ppm corresponding to the alkylidene proton ( supporting information ) . we found that cyclohexene 6 reacts with ring - opened monomer 3 enoic carbene 1.5 times faster ( t1/2 = 28 1 min ) than with the corresponding enoic carbene from monomer 4 ( t1/2 = 43 5 min ) ( figure 5 and supporting information ) . when the formation of ru alkylidene ( [ ru]-b - a ) was complete as judged by integration of the resonance at 19.0 ppm , 1 equiv of monomer a was added to investigate the rate of ring - opening catalyzed by [ ru]-b - a . we examined all four cases of double rom : rom of 3 with [ ru]-6 - 3 and with [ ru]-6 - 4 and rom of 4 with [ ru]-6 - 4 and with [ ru]-6 - 3 . the disappearance of the monomer a alkene signal at 6.7 ppm and that of the [ ru]-b - a alkylidene signal at 19.0 ppm were monitored as a function of time . both signals disappeared at the same rate as measured by comparison of the integrals with that of the signal for ester peaks . we found that reaction of monomer 3 with [ ru]-6 - 4 ( t1/2 = 26 1 min ) was 27% faster than its reaction with [ ru]-6 - 3 ( t1/2 = 33 1 min ) . in the case of the reaction of monomer 4 with [ ru]-6-a , the rate with [ ru]-6 - 4 ( t1/2 = 41 4 min ) is 17% faster than the rate with [ ru]-6 - 3 ( t1/2 = 48 2 min ) . moreover , oligomers derived from monomer 3 as either a or a failed to completely convert to [ ru]-6-a-6-a ; this result is consistent with the premise that competing cross - metathesis reactions dominate the reaction ( figure 5 ) . kinetic monitoring of double ring - opening metathesis ( arom-2 ) reactions of monomer a ( 3 or 4 ) with [ ru]-6-a ( scheme 1b ) . time zero corresponds to the addition of 1 equiv of monomer a ( 3 or 4 ) to 1 equiv of [ ru]-6-a in the presence of excess cyclohexene 6 . mole fraction of ru alkylidene at 19.0 ppm was determined by integration of the ru alkylidene resonance relative to the methyl ester resonances between 3.5 and 3.8 ppm . the mole percent of [ ru]-6-a at time zero was only 3042% due to the low concentrations , and thus , the extended reaction times used in the initial arom to generate [ ru]-6-a . each experiment was performed at least twice , and data from representative experiments are shown . although the rates of the second rom did not vary widely , the rom reaction appears to be very sensitive to long - range polymer structure , i.e. , the presence of a five - membered ring in the backbone one position removed from the living [ ru ] species reduces the reaction rate of either bicyclic monomer with the unhindered [ ru]-alkylidene . the rates of reaction indicate that the backbone containing a six - membered ring ( derived from [ 4.2.0 ] monomer ) is superior to the backbone containing a five - membered ring ( derived from [ 3.2.0 ] monomer ) for propagation . we ascribe the differences in reactivity between oligomers derived from monomer 3 versus monomer 4 to the differences in dihedral angles between the cis-1,2 substituents of cyclopentane versus those of cyclohexane ( 2040 , depending on the conformation , and 60 , respectively ) . these dihedral angles determine the relative orientation of the two polymer chain ends as the backbone extends from the cyclic moiety . if the chain ends are aligned , intramolecular cross - metathesis will ensue , as is the case for aromp of monomers 3 and 6 . if access of the incoming monomer to [ ru]-alkylidene is hindered , the rate of propagation will be suppressed and the polymerization reaction is unable to compete with cross - metathesis . thus , despite the higher strain and inherent reactivity of monomer 3 , the resulting polymer backbone appears to hinder propagation and to favor cross - metathesis ; both effects lead to the premature termination of polymerization . we have demonstrated that alternating copolymers are synthetically accessible via aromp with bicyclic carbomethoxy olefin monomers 35 and cyclohexene . these aromp - active monomers do not self - metathesize regardless of monomer feed ratios or concentrations . thus , formation of homopolymeric blocks , as is observed in some other systems , does not occur in the 35/6 aromp systems . ruthenium - catalyzed ring - opening metathesis of cyclohexene and methyl bicyclo[4.2.0]oct-7-ene-7-carboxylate , 4 , provides rigorously linear and alternating copolymers free of backbiting and chain transfer . the resulting polymer backbone constrained by a cis-1,2-substituted cyclohexane provides an exciting alternative to traditional norbornyl - derived polymers for the preparation of functional alternating copolymers . Output:	strained bicyclic carbomethoxy olefins were utilized as substrates in alternating ring - opening metathesis polymerization and found to provide low - dispersity polymers with novel backbones . the polymerization of methyl bicyclo[4.2.0]oct-7-ene-7-carboxylate with cyclohexene in the presence of the fast - initiating grubbs catalyst ( h2imes)(3-br - pyr)2cl2ru = chph leads to a completely linear as well as alternating copolymer , as demonstrated by nmr spectroscopy , isotopic labeling , and gel permeation chromatography . in contrast , intramolecular chain - transfer reactions were observed with [ 5.2.0 ] and [ 3.2.0 ] bicyclic carbomethoxy olefins , although to a lesser extent than with the previously reported monocyclic cyclobutenecarboxylic ester monomers [ songa . ; parkerk . a. ; sampsonn . s.j . am . chem . soc.2009 , 131 , 344419275253 ] . inclusion of cyclohexyl rings fused to the copolymer backbone minimizes intramolecular chain - transfer reactions and provides a framework for creating alternating functionality in a one - step polymerization .
PubmedSumm118848	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: cardiac valvular surgery has excellent long - term survival results and is the treatment of choice in patients with severe valvular disease ; however , postsurgical morbidity remains high . frequent complications such as atrial fibrillation ( af ) may worsen prognosis , prolong hospital stay and increase medical costs . therefore , it is important to improve strategies to reduce postsurgical morbidity . in this respect , statins are interesting drugs . statins have shown to reduce morbidity and mortality in a broad range of patients with cardiovascular diseases [ 2 , 3 ] . in addition to cholesterol - lowering properties , experimental and clinical data suggest that statins may also exhibit anti - inflammatory , endothelial protective , antioxidative and anti - remodelling effects [ 48 ] . indeed , statins may prevent af after coronary artery bypass grafting ( cabg ) surgery [ 9 , 10 ] ; however , this does not prove a pleiotropic effect since this may be caused by the vasoprotective effects of statins and reduction of ischaemia , thereby preventing af . ischaemia due to coronary artery disease is less likely to play a major role after valvular surgery ; however , few data exist on the possible protective effects of statins after cardiac valvular surgery . therefore , we hypothesise that statins may reduce af and shorten hospital stay after cardiac valvular surgery . in retrospect , 272 consecutive patients undergoing cardiac valvular surgery in our department between july 1996 and march 2004 were identified . patients with af on the day of surgery or with concomitant cabg were excluded to avoid treatment bias due to symptomatic coronary artery disease . patients referred from other hospitals were excluded because of incomplete pre- and postoperative data for this observational study . after these exclusions , our study cohort consisted of 272 patients who underwent cardiac valvular surgery without concomitant cabg in our hospital during this period . in addition , admission levels of haemoglobin and creatinine were retrieved as well as the maximal creatinine phosphokinase in the first 24 h after surgery . each medical chart was reviewed for preoperative medication , including statins , -adrenergic receptor blockers , angiotensin - converting enzyme inhibitors , angiotensin ii receptor blockers and antiarrhythmic drugs . these drugs needed to be prescribed for at least 1 week prior to surgery if a drug was considered to be given . af was defined as any episode of af longer than 10 s. rhythm data during admission were attained by retrieving all electrocardiographic and holter recordings from the medical chart . data on previous episodes of af were attained from the chart and from our clinical ecg database . in retrospect , 272 consecutive patients undergoing cardiac valvular surgery in our department between july 1996 and march 2004 were identified . patients with af on the day of surgery or with concomitant cabg were excluded to avoid treatment bias due to symptomatic coronary artery disease . patients referred from other hospitals were excluded because of incomplete pre- and postoperative data for this observational study . after these exclusions , our study cohort consisted of 272 patients who underwent cardiac valvular surgery without concomitant cabg in our hospital during this period . echocardiographic data were collected from our routine clinical database . in addition , admission levels of haemoglobin and creatinine were retrieved as well as the maximal creatinine phosphokinase in the first 24 h after surgery . each medical chart was reviewed for preoperative medication , including statins , -adrenergic receptor blockers , angiotensin - converting enzyme inhibitors , angiotensin ii receptor blockers and antiarrhythmic drugs . these drugs needed to be prescribed for at least 1 week prior to surgery if a drug was considered to be given . af was defined as any episode of af longer than 10 s. rhythm data during admission were attained by retrieving all electrocardiographic and holter recordings from the medical chart . data on previous episodes of af were attained from the chart and from our clinical ecg database . results are presented as the mean value sd for continuous variables and as the percentage of total patients for categorical data . the independent samples t test was used for comparison of continuous variables and the test for categorical variables . potential predictors of hospital stay were related to the duration of stay in days using linear regression analysis . for this purpose , therefore , we first assessed whether the missing status was statistically informative using a dummy variable . since this was not the case , the missing values were imputed using the mean value of the whole group approach . multivariable logistic regression was performed to test whether statin prescription was associated with postoperative af occurrence when correcting for potential confounders . variables entered in the model were age , sex , new york heart association class , previous af , history of percutaneous coronary interventions ( pci ) , history of cabg , prior valvular surgery , pulmonary hypertension , haemoglobin level , atrial size , the use of -blockers , antiarrhythmic drugs , aortic valve surgery , combined surgery on more than one valve and the use of statin and the propensity score . the effect of statin prescription on occurrence of postoperative af might be biased by the absence of randomisation in this observational study , and therefore a propensity score was added to the multivariate logistic regression model in order to correct as well as possible for the propensity of a physician to select patients for prescribing statins . individual propensity scores were calculated by means of backward deletion logistic regression ( see methods ) . the propensity score was added as a continuous variable to the multivariable logistic regression analysis . the variable for statin prescription and its propensity score were kept at all times in the model regardless of their significance , since this was the main effect we wanted to test . the mean age of the patients was 65 11 years , the mean left ventricular ejection fraction was 57 12% , 142 patients ( 52% ) were male and 20% had a history of af ( table 1 ) . aortic valve replacement was performed in 189 ( 70% ) patients , mitral valve repair or replacement in 78 ( 29% ) patients and 21 ( 8% ) patients had surgery on more than one valve . table 1 shows the baseline characteristics and a comparison of statin vs non - statin users . allstatin usersnon - statin userspn = 272n = 79n = 193age ( years)65 1165 1165 110.510male ( % ) 142 ( 52)41 ( 52)101 ( 52)0.948previous history , n ( % ) nyha i37 ( 14)8 ( 11)29 ( 15 ) nyha ii55 ( 21)16 ( 22)39 ( 21 ) nyha iii146 ( 56)41 ( 56)105 ( 56 ) nyha iv23 ( 9)8 ( 11)15 ( 8)0.728 af54 ( 20)17 ( 22)37 ( 19)0.659 pci37 ( 14)20 ( 25)17 ( 9)<0.001 cabg26 ( 10)19 ( 24)7 ( 4)<0.001 valve surgery23 ( 9)10 ( 13)13 ( 7)0.111 diabetes27 ( 10)17 ( 22)10 ( 5)<0.001 copd31 ( 12)8 ( 11)23 ( 12)0.743 hypertension110 ( 40)37 ( 47)73 ( 38)0.169 pulmonary hypertension107 ( 41)30 ( 39)77 ( 42)0.641laboratory haemoglobin ( mmol / l)8.4 1.08.4 1.08.4 1.00.741 creatinine ( mol / l)98 ( 78104)106 ( 74107)94 ( 79103)0.604 cholesterol ( mg / dl)212 49190 43222 48<0.001echocardiography left atrial size ( mm)48 849 748 80.894 lvef ( % ) 57 1256 1158 120.349drugs , n ( % ) ace - i127 ( 47)41 ( 52)86 ( 45)0.271 beta - blocker87 ( 32)40 ( 51)47 ( 24)<0.001 aad44 ( 16)12 ( 15)32 ( 17)0.777surgery , n ( % ) emergency12 ( 4)3 ( 4)9 ( 5)0.752 aortic valve189 ( 70)57 ( 72)132 ( 68)0.541 mitral valve78 ( 29)19 ( 24)59 ( 31)0.280 > 1 valve21 ( 8)2 ( 3)19 ( 10)0.043 mechanical prosthesis201 ( 75)62 ( 81)139 ( 72)0.166 ecc time ( min)105 42102 35106 450.430 acc time ( min)75 2970 2277 310.075nyha new york heart association , copd chronic obstructive pulmonary disease , ace - i angiotensin - converting enzyme inhibitor or angiotensin ii receptor blocker , aad class i or iii antiarrhythmic drugs , ecc extracorporal circulation clamp time , acc aorta circulation clamp , lvef left ventricular ejection fraction25th and 75th percentilesmann whitney u results nyha new york heart association , copd chronic obstructive pulmonary disease , ace - i angiotensin - converting enzyme inhibitor or angiotensin ii receptor blocker , aad class i or iii antiarrhythmic drugs , ecc extracorporal circulation clamp time , acc aorta circulation clamp , lvef left ventricular ejection fraction 25th and 75th percentiles mann whitney u results statin users more often had diabetes mellitus ( 22% vs 5% , p < 0.001 ) and more often used -blockers ( 51% vs 24% , p < 0.001 ) . in addition , these patients more often had a history of pci ( 25% vs 9% , p < patients in the non - statin group more often had surgery on more than one valve ( 10% vs 3% , p = 0.043 ) , and a higher cholesterol level ( 222 48 vs 190 43 mg / dl , p < 0.001 ) . af occurred after a mean of 4.0 3.7 days in patients without and after 3.7 3.3 days in patients with a statin ( p = 0.615 ) . table 2 shows the univariate differences in characteristics between patients who had postoperative af vs the ones without af . in addition , they more often had a history of pci or pulmonary hypertension , had a lower haemoglobin level , a larger left atrium , more often used an antiarrhythmic drug and were more often operated on more than one valve . af occurred in 149/272 ( 55% ) of the patients undergoing surgery in sinus rhythm . forty - three out of 79 patients ( 54% ) taking statins developed af , compared with 106/193 ( 55% ) patients not taking these cholesterol - lowering drugs ( p = 0.941 ) . the incidence of af in patients without any previous episode of af was 49% in non - statin users vs 50% in statin users , ( p = 0.864 ) . no afafpn = 123n = 149age ( years)63 1267 100.002male , n ( % ) 48 ( 39)82 ( 55)0.009previous history , n ( % ) nyha i24 ( 21)13 ( 9 ) nyha ii20 ( 17)35 ( 24 ) nyha iii64 ( 55)82 ( 57 ) nyha iv9 ( 8)14 ( 10)0.047 af12 ( 10)42 ( 28)<0.001 pci19 ( 15)12 ( 8)0.056 cabg16 ( 13)10 ( 7)0.079 valve surgery29 ( 10)11 ( 13)0.198 diabetes10 ( 8)17 ( 11)0.368 copd17 ( 14)14 ( 10)0.219 hypertension47 ( 38)63 ( 42)0.496 pulmonary hypertension36 ( 32)71 ( 49)0.006laboratory haemoglobin ( mmol / l)8.6 0.98.3 1.10.019 creatinine ( mol / l)104 ( 78106)92 ( 78102)0.947 cholesterol ( mg / dl)211 51212 470.781echocardiography left atrial size ( mm)47 849 30.048 lvef ( % ) 57 1357 110.824drugs , n ( % ) ace - i53 ( 43)74 ( 50)0.279 beta - blocker33 ( 27)54 ( 36)0.098 statin36 ( 29)43 ( 29)0.941 aad13 ( 11)31 ( 21)0.023surgery , n ( % ) emergency7 ( 6)5 ( 3)0.351 aortic valve92 ( 75)97 ( 65)0.084 mitral valve32 ( 26)46 ( 31)0.378 > 1 valve5 ( 4)16 ( 11)0.037 mechanical prosthesis95 ( 77)106 ( 73)0.384 ecc time ( min)103 43106 410.554 acc time ( min)74 3076 280.668nyha new york heart association , copd chronic obstructive pulmonary disease , ace - i angiotensin - converting enzyme inhibitor or angiotensin ii receptor blocker , aad class i or iii antiarrhythmic drugs , ecc extracorporal circulation clamp time , acc aorta circulation clamp , lvef left ventricular ejection fraction25 and 75 percentilesmann whitney u results nyha new york heart association , copd chronic obstructive pulmonary disease , ace - i angiotensin - converting enzyme inhibitor or angiotensin ii receptor blocker , aad class i or iii antiarrhythmic drugs , ecc extracorporal circulation clamp time , acc aorta circulation clamp , lvef left ventricular ejection fraction 25 and 75 percentiles mann whitney u results in the multivariate analysis , statin use was not associated with af occurrence ( p = 0.345 ) . significant predictors of postoperative af were age , a previous episode of af , a history of cabg and pulmonary hypertension ( table 3 ) . the mean propensity score for statin use was 0.27 ( 25th and 75th percentiles , 0.05 and 0.42 , respectively ) . p valueor ( 95% ci)age0.0021.05 ( 1.0171.074)previous af0.0014.55 ( 1.90510.856)previous cabg0.0290.24 ( 0.0670.867)pulmonary hypertension0.0221.98 ( 1.1023.557)statin0.3451.49 ( 0.6513.403 ) interactions were observed between statin and haemoglobin levels ( p = 0.024 ) ; however , statin therapy was still not predictive of postoperative af in patients with a mean haemoglobin of 8.41 mmol / l ( p = 0.914 ) vs those with levels > 8.41 mmol / l ( p = 0.552 ) . other interactions were noted between age and sex ( p = 0.013 ) and between history of af and surgery on more than one valve ( p = 0.012 ) . the mean length of hospital stay was 13.9 days ( 25th and 75th percentiles , 7 and 18 days , respectively ) . the use of statins was not associated with shorter hospitalisation , 4% decrease in hospital stay duration , 95% ci 18 12% ( p = 0.602 ) . in - hospital mortality was 4% in both statin and non - statin users ( p = 0.971 ) . one may argue that if statins were not able to prevent af prior to surgery , they may also not prevent af after surgery . therefore , another subanalysis was performed in patients without a history of af . by excluding these , 218 ( 80% ) patients remained in the model , of which 62 ( 28% ) used a statin and 107 ( 49% ) developed af . multivariate predictors of postsurgical af were age ( p = 0.015 ) and haemoglobin levels prior to surgery ( p = 0.035 ) . still , the use of a statin was not associated with af ( p = 0.392 ) . another subanalysis was performed in patients without previous pci or cabg , leaving a total of 226 ( 83% ) patients . in this subgroup , 52 ( 23% ) when excluding patients with prior cabg , none of the patients undergoing prior valve surgery remained . except for this , the same variables as in the main model were entered in the multivariate analysis , as all had univariate p values < 0.10 . multivariate predictors of postsurgical af were age ( p = 0.005 ) and prior af ( p = 0.001 ) . the use of statin was not associated with af ( p = 0.782 ) . in this model af occurred after a mean of 4.0 3.7 days in patients without and after 3.7 3.3 days in patients with a statin ( p = 0.615 ) . table 2 shows the univariate differences in characteristics between patients who had postoperative af vs the ones without af . in addition , they more often had a history of pci or pulmonary hypertension , had a lower haemoglobin level , a larger left atrium , more often used an antiarrhythmic drug and were more often operated on more than one valve . af occurred in 149/272 ( 55% ) of the patients undergoing surgery in sinus rhythm . forty - three out of 79 patients ( 54% ) taking statins developed af , compared with 106/193 ( 55% ) patients not taking these cholesterol - lowering drugs ( p = 0.941 ) . the incidence of af in patients without any previous episode of af was 49% in non - statin users vs 50% in statin users , ( p = 0.864 ) . no afafpn = 123n = 149age ( years)63 1267 100.002male , n ( % ) 48 ( 39)82 ( 55)0.009previous history , n ( % ) nyha i24 ( 21)13 ( 9 ) nyha ii20 ( 17)35 ( 24 ) nyha iii64 ( 55)82 ( 57 ) nyha iv9 ( 8)14 ( 10)0.047 af12 ( 10)42 ( 28)<0.001 pci19 ( 15)12 ( 8)0.056 cabg16 ( 13)10 ( 7)0.079 valve surgery29 ( 10)11 ( 13)0.198 diabetes10 ( 8)17 ( 11)0.368 copd17 ( 14)14 ( 10)0.219 hypertension47 ( 38)63 ( 42)0.496 pulmonary hypertension36 ( 32)71 ( 49)0.006laboratory haemoglobin ( mmol / l)8.6 0.98.3 1.10.019 creatinine ( mol / l)104 ( 78106)92 ( 78102)0.947 cholesterol ( mg / dl)211 51212 470.781echocardiography left atrial size ( mm)47 849 30.048 lvef ( % ) 57 1357 110.824drugs , n ( % ) ace - i53 ( 43)74 ( 50)0.279 beta - blocker33 ( 27)54 ( 36)0.098 statin36 ( 29)43 ( 29)0.941 aad13 ( 11)31 ( 21)0.023surgery , n ( % ) emergency7 ( 6)5 ( 3)0.351 aortic valve92 ( 75)97 ( 65)0.084 mitral valve32 ( 26)46 ( 31)0.378 > 1 valve5 ( 4)16 ( 11)0.037 mechanical prosthesis95 ( 77)106 ( 73)0.384 ecc time ( min)103 43106 410.554 acc time ( min)74 3076 280.668nyha new york heart association , copd chronic obstructive pulmonary disease , ace - i angiotensin - converting enzyme inhibitor or angiotensin ii receptor blocker , aad class i or iii antiarrhythmic drugs , ecc extracorporal circulation clamp time , acc aorta circulation clamp , lvef left ventricular ejection fraction25 and 75 percentilesmann whitney u results nyha new york heart association , copd chronic obstructive pulmonary disease , ace - i angiotensin - converting enzyme inhibitor or angiotensin ii receptor blocker , aad class i or iii antiarrhythmic drugs , ecc extracorporal circulation clamp time , acc aorta circulation clamp , lvef left ventricular ejection fraction 25 and 75 percentiles mann whitney u results in the multivariate analysis , statin use was not associated with af occurrence ( p = 0.345 ) . significant predictors of postoperative af were age , a previous episode of af , a history of cabg and pulmonary hypertension ( table 3 ) . the mean propensity score for statin use was 0.27 ( 25th and 75th percentiles , 0.05 and 0.42 , respectively ) . p valueor ( 95% ci)age0.0021.05 ( 1.0171.074)previous af0.0014.55 ( 1.90510.856)previous cabg0.0290.24 ( 0.0670.867)pulmonary hypertension0.0221.98 ( 1.1023.557)statin0.3451.49 ( 0.6513.403 ) interactions were observed between statin and haemoglobin levels ( p = 0.024 ) ; however , statin therapy was still not predictive of postoperative af in patients with a mean haemoglobin of 8.41 mmol / l ( p = 0.914 ) vs those with levels > 8.41 mmol / l ( p = 0.552 ) . other interactions were noted between age and sex ( p = 0.013 ) and between history of af and surgery on more than one valve ( p = 0.012 ) . the mean length of hospital stay was 13.9 days ( 25th and 75th percentiles , 7 and 18 days , respectively ) . the use of statins was not associated with shorter hospitalisation , 4% decrease in hospital stay duration , 95% ci 18 12% ( p = 0.602 ) . in - hospital mortality was 4% in both statin and non - statin users ( p = 0.971 ) . one may argue that if statins were not able to prevent af prior to surgery , they may also not prevent af after surgery . therefore , another subanalysis was performed in patients without a history of af . by excluding these , 218 ( 80% ) patients remained in the model , of which 62 ( 28% ) used a statin and 107 ( 49% ) developed af . multivariate predictors of postsurgical af were age ( p = 0.015 ) and haemoglobin levels prior to surgery ( p = 0.035 ) . still , the use of a statin was not associated with af ( p = 0.392 ) . another subanalysis was performed in patients without previous pci or cabg , leaving a total of 226 ( 83% ) patients . in this subgroup , 52 ( 23% ) used a statin and 124 patients ( 55% ) developed af . when excluding patients with prior cabg , none of the patients undergoing prior valve surgery remained . except for this , the same variables as in the main model were entered in the multivariate analysis , as all had univariate p values < 0.10 . multivariate predictors of postsurgical af were age ( p = 0.005 ) and prior af ( p = 0.001 ) . the use of statin was not associated with af ( p = 0.782 ) . in this model this study shows that treatment with statins is not associated with a reduction of af in patients undergoing valvular surgery . in line with these observations , statins were not associated with a shorter hospital stay . risk factors for atherosclerotic disease such as hypertension and age are associated with an increased risk for af . this suggests an association between af and atherosclerotic vascular disease . in contrary to most studies , we excluded concomitant cabg surgery to minimise the effect of atherosclerotic vascular disease . thus far , several studies after thoracic surgery have shown conflicting results . four observational studies in patients after cabg and non - cardiac thoracic surgery have shown a decreased postoperative af incidence with the use of a statin [ 1215 ] . in addition , a randomised trial of 200 patients showed that in patients after cabg surgery , af was reduced by almost 40% with atorvastatin starting 1 week before the operation ( 35% vs 57% , p = 0.003 ) . this is in accordance with the finding that statins may reduce af in patients with symptomatic coronary artery disease . such an effect seems plausible since statins can prevent atherosclerosis and its consequences ; however , these data are in conflict with a large retrospective cohort analysis in 4,044 patients in which statins were not associated with af reduction after cabg . in concert with this , we found no relation between statin treatment and postoperative af in patients after valvular surgery . it may be assumed that patients with coronary artery disease respond better to statins than patients undergoing valvular surgery . in addition , the severe valvular disease has already led to a substrate for af , irrespective of the inflammatory effects caused by the operation . this is illustrated by a higher incidence of af after valvular surgery compared with cabg surgery . in the latter , postoperative af is more likely to depend on excess triggers caused by the inflammatory response to surgery . therefore , reduction of inflammation by statins may decrease the incidence of af in the cabg patients , but not after valvular surgery . our patients may differ significantly from previous studies since they had a high postoperative af rate suggesting significant remodelling and inflammation not suppressible by statins . firstly , statins may exert systemic anti - inflammatory effects by reducing t cell activation , thereby reducing inflammatory cytokine production such as il-6 and c - reactive protein ( crp ) [ 17 , 18 ] . a high crp level is a risk factor for cardiovascular events , including the development and maintenance of af [ 4 , 1921 ] . in addition , higher crp levels are associated with higher af burden . further evidence of an inflammatory basis of af is supported by atrial biopsies , showing that atrial myocarditis is frequent in lone af . inflammation may lead to af by slowing atrial conduction , thereby facilitating re - entry [ 22 , 23 ] . other reported beneficial effects of statins to prevent af are their antioxidant , anti - remodelling properties , modification of neurohormonal activation of the renin angiotensin and the autonomic nervous system , direct antiarrhythmic effects by cell membrane ion channel stabilisation , direct protection of the ischaemic myocardium or modulation of the extracellular matrix . although the statin group more often had diabetes mellitus , the non - statin group more often had surgery on more than one valve and a higher cholesterol level ; however , by adding propensity scores to the multivariate analysis , we corrected as well as possible for the differences between the statin and non - statin users . in addition , the sample size may be too small for drawing firm conclusions ; however , no small trend in favour of statin use was seen . in the univariate analysis , a statin was used in 29% of patients with and without af ( p = 0.941 in univariate analysis ) . therefore , it is unlikely that sample size precluded significance , although it can not be excluded . all patients in the statin group used a statin for at least 1 week . we did not analyse duration , dosing and the different types of statins . despite these drawbacks , our study does not support the hypothesis that pleiotropic effects of statins may decrease af in this population . risk factors for atherosclerotic disease such as hypertension and age are associated with an increased risk for af . this suggests an association between af and atherosclerotic vascular disease . in contrary to most studies , we excluded concomitant cabg surgery to minimise the effect of atherosclerotic vascular disease . thus far four observational studies in patients after cabg and non - cardiac thoracic surgery have shown a decreased postoperative af incidence with the use of a statin [ 1215 ] . in addition , a randomised trial of 200 patients showed that in patients after cabg surgery , af was reduced by almost 40% with atorvastatin starting 1 week before the operation ( 35% vs 57% , p = 0.003 ) . this is in accordance with the finding that statins may reduce af in patients with symptomatic coronary artery disease . such an effect seems plausible since statins can prevent atherosclerosis and its consequences ; however , these data are in conflict with a large retrospective cohort analysis in 4,044 patients in which statins were not associated with af reduction after cabg . in concert with this , we found no relation between statin treatment and postoperative af in patients after valvular surgery . it may be assumed that patients with coronary artery disease respond better to statins than patients undergoing valvular surgery . in addition , the severe valvular disease has already led to a substrate for af , irrespective of the inflammatory effects caused by the operation . this is illustrated by a higher incidence of af after valvular surgery compared with cabg surgery . in the latter , postoperative af is more likely to depend on excess triggers caused by the inflammatory response to surgery . therefore , reduction of inflammation by statins may decrease the incidence of af in the cabg patients , but not after valvular surgery . our patients may differ significantly from previous studies since they had a high postoperative af rate suggesting significant remodelling and inflammation not suppressible by statins . firstly , statins may exert systemic anti - inflammatory effects by reducing t cell activation , thereby reducing inflammatory cytokine production such as il-6 and c - reactive protein ( crp ) [ 17 , 18 ] . a high crp level is a risk factor for cardiovascular events , including the development and maintenance of af [ 4 , 1921 ] . in addition , higher crp levels are associated with higher af burden . further evidence of an inflammatory basis of af is supported by atrial biopsies , showing that atrial myocarditis is frequent in lone af . inflammation may lead to af by slowing atrial conduction , thereby facilitating re - entry [ 22 , 23 ] . other reported beneficial effects of statins to prevent af are their antioxidant , anti - remodelling properties , modification of neurohormonal activation of the renin angiotensin and the autonomic nervous system , direct antiarrhythmic effects by cell membrane ion channel stabilisation , direct protection of the ischaemic myocardium or modulation of the extracellular matrix . although the statin group more often had diabetes mellitus , the non - statin group more often had surgery on more than one valve and a higher cholesterol level ; however , by adding propensity scores to the multivariate analysis , we corrected as well as possible for the differences between the statin and non - statin users . in addition , the sample size may be too small for drawing firm conclusions ; however , no small trend in favour of statin use was seen . in the univariate analysis , a statin was used in 29% of patients with and without af ( p = 0.941 in univariate analysis ) . therefore , it is unlikely that sample size precluded significance , although it can not be excluded . all patients in the statin group used a statin for at least 1 week . we did not analyse duration , dosing and the different types of statins . despite these drawbacks , our study does not support the hypothesis that pleiotropic effects of statins may decrease af in this population . statins are not associated with a decreased incidence of af after cardiac valvular surgery . our results conflict with most reports in patients with vascular disease further research should focus on the role of statins in subjects who are not vascularly compromised . Output:	introductionstatins may theoretically reduce postoperative atrial fibrillation ( af ) in patients after cardiac valvular surgery due to preservation of endothelial function and anti - ischaemic , anti - inflammatory and anti - remodelling effects.methodstwo hundred seventy - two patients who underwent cardiac workup and subsequently cardiac valvular surgery without af and concomitant coronary artery bypass grafting ( cabg ) at our hospital were selected . preoperative drug use and postoperative af were recorded . af was defined as any episode of af longer than 10 s. in addition , results from echocardiography and blood samples were retrieved.resultsbaseline characteristics were as follows : mean age was 65 11 years , 142 ( 52% ) patients were male , 189 ( 70% ) had undergone aortic valve surgery and the mean left ventricular ejection fraction was 57 12% . statins were used by 79 patients ( 29% ) . statin users , more often , had a prior percutaneous coronary intervention ( 25% vs 9% , p < 0.001 ) or cabg ( 24% vs 4% , p < 0.001 ) , diabetes mellitus ( 22% vs 5% , p < 0.001 ) and more often used -blockers ( 51% vs 24% , p < 0.001 ) . patients in the non - statin group more often had surgery on more than one valve ( 10% vs 3% , p = 0.043 ) and had a higher cholesterol level ( 222 48 vs 190 43 mg / dl , p < 0.001 ) . postoperative af occurred in 54% ( 43/79 ) of the patients with and in 55% ( 106/193 ) of the patients without statins ( p = 0.941 ) . there was also no difference in the timing of onset of af or duration of hospital stay.conclusionin this observational study , statin use was not associated with a reduced incidence of af in patients after cardiac valvular surgery .
PubmedSumm118849	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: mediastinal germ cell tumors ( gcts ) are rare , accounting for 34%percnt ; of all gcts in both adults and children . they are divided into several categories : seminoma , malignant nonseminomatous gcts [ nsgcts ; embryonal carcinoma ( ec ) , yolk sac tumor , choriocarcinoma ( cc ) , and mixed gct ] , mature teratoma , and immature teratoma . of these , the prognosis for nsgcts of mediastinal origin is worse than that of tumors originating from gonadal or extragonadal sites . according to the risk classification of the international germ cell cancer collaborative group ( igcccg ) , mediastinal nsgcts are classified as poor risk , with a 5-year relapse - free chance of survival of 40%percnt ; , regardless of the presence or absence of metastasis , or of levels of the serum tumor markers , lactate dehydrogenase ( ldh ) , -fetoprotein ( afp ) , and human chorionic gonadotropin ( hcg ) . the standard care for advanced nsgcts is combination chemotherapy with bleomycin , etoposide , and cisplatin ( bep ) , followed by resection of the residual tumor . serum ldh , afp , and hcg levels should be measured to monitor the response to treatment . some studies have indicated that a logarithmic decrease in these markers , consistent with their respective serum half - life time , predicts a good treatment outcome . here , we report a rare case of a mediastinal gct that exhibited rapidly progressive disease , which eventually killed the patient , despite an optimal decrease in serum tumor markers . we also conducted a pathological and biological analysis of autopsy and biopsy specimens to gain insight into the cause of this peculiar clinical course . a 34-year - old man who had developed gynecomastia about 4 months previously visited a local hospital on july 10 , 2013 , due to hemosputum , which had developed 3 days previously . chest radiography and computed tomography ( ct ) both showed a very large mediastinal tumor with multiple lung nodules . he was referred to a cancer center , where a core - needle biopsy of the anterior mediastinal tumor was performed . since his dyspnea and hemosputum were getting worse , he was referred to our hospital on july 29 , 2013 . on examination , his eastern cooperative oncology group ( ecog ) performance status was 2 ; body temperature was 37.5c , blood pressure 102/62 mm hg , pulse 93 beats per min ( regular ) , respiratory rate 28/min , and oxygen saturation 8892%percnt ; ( room air , spontaneous respiration ) . imaging studies , including chest and abdominal - plane ct , positron emission tomography ct , and brain magnetic resonance imaging ( mri ) , showed a bulky anterior mediastinal tumor with liver , lung , and brain nodules ( fig . 1a laboratory findings were as follows : white blood cell count 169 10 /l , hemoglobin 10.1 g / dl , c - reactive protein 13.7 mg / dl , aspartate aminotransferase ( ast ) 63 u / ml , alanine aminotransferase 76 u / ml , ldh 656 u / ml , total bilirubin 1.6 mg / dl , afp 1 ng / ml , and hcg 289,500 miu / ml . the biopsy specimen from the anterior mediastinum was diagnosed as an nsgct , most likely an ec based on positive hcg and cd30 staining ( fig . 1 g , h , respectively ) . according to the risk classification of the igcccg , the patient was classified as having a poor risk because of his primary mediastinal tumor . we immediately initiated chemotherapy with a bep regimen ( bleomycin 30 u / body , days 2 , 9 , and 16 ; etoposide 100 mg / m , days 15 , and cisplatin 20 mg / m , days 15 , q 3 weeks ) on july 30 , the day after admission . unexpectedly , we observed an increased number and size of cystic liver lesions on ct on august 22 compared to those at admission ( fig . 2b d ) . because of his optimal tumor marker response and a high fever at that point , we first suspected liver abscesses in the patient and initiated meropenem treatment on august 22 . intracystic fluid aspiration and a liver biopsy were undertaken to determine whether the liver lesions were tumors or abscesses on august 23 . although the intracystic fluid was a yellowish brown , cloudy , odorless solution , compatible with an abscess , it was aseptic microscopically and on culturing , and negative for malignant cells on cytology . the liver biopsy specimen was composed of normal hepatocytes with no evidence of tumor or infection , including mycobacterium and mycosis . the liver lesions had increased further in size on ct on august 28 ( fig . 2e ) , and we initiated treatment with amphotericin b on the assumption of a fungal infection . we considered his condition to indicate clinically progressive disease and decided to give gemcitabine combined with paclitaxel ( gp ; gemcitabine 1,250 mg / m , day 1 ; paclitaxel 135 mg / m , day 1 ) on august 30 . an ifosfamide - based standard salvage regimen was considered unfeasible based on his poor general condition . though his liver enzyme levels transitionally decreased over several days after gp ( fig . 2a ) , hepatic failure associated with increased serum total bilirubin and a rapid increase in liver enzyme levels ( ast 813 u / ml on september 12 ; fig . 2a ) were seen ; multiorgan failure subsequently developed , and the patient finally died on september 13 . autopsy findings were as follows : the liver contained cystic tumors of various sizes up to 10 cm in diameter and filled with cloudy necrotic material , where we found no evidence of infection ( fig . 3c ) tumors showed the presence of very few viable syncytiotrophoblast cells , and seemingly cc . immunohistochemical analysis of the mediastinal tumor at autopsy showed the diffuse expression of hcg , including in necrotic areas ( fig . collectively , these findings suggest that this particular tumor was a mixed gct composed of cc ( hcg - positive ) and ec ( cd30-positive ) . given preclinical studies showing that matrix metalloproteinase-2 ( mmp-2 ) was involved in the invasive phenotype of a cc cell line and in trophoblast cell invasion , we conducted an immunohistochemical analysis for mmp-2 . as shown in figure 3 g , we found that mmp-2 was expressed in primary mediastinal tumor cells as well as in liver lesions ( both viable tumor cells and debris ) ( fig . these results strongly suggested that the gct was highly invasive , leading to extensive metastases and aggressive expansion in the liver . we report a rare case of a mediastinal gct that exhibited a discrepancy between the time course of serum hcg levels , imaging studies , and the patient 's condition . in general , an unsatisfactory decline in serum levels of tumor markers in the first 12 cycles of chemotherapy is associated with a worsening outcome [ 9 , 10 , 11 ] . in previously published papers , the cutoff value of the half - life of hcg was defined to be between 3.0 and 3.5 days [ 9 , 10 , 11 ] . in our case , the estimated half - life of hcg was nearly 3.3 days ( between days 1 and 22 of the first cycle of chemotherapy ) , as calculated by a previously described method . therefore , it is surprising that the metastatic lesions in the liver were enlarged by about the third week of the first chemotherapy regimen , despite an optimal decrease in serum hcg . since we detected no infectious pathogens in the punctatum or infectious changes in the liver specimen , we eventually speculated that this might have been due to disease progression but not to liver abscesses , which was subsequently confirmed , but only at autopsy . several examples reporting the enlargement of a mediastinal gct despite a decline in tumor markers have been reported . one is the growing teratoma syndrome , first described by logothetis et al . in 1982 this is a rare phenomenon characterized by a growing lesion despite the normalization of serum markers after chemotherapy for nsgct . importantly , a mature teratoma is normally involved , which is usually negative for hcg . in our case , the pathological analysis showed that the viable cells in the metastatic lesion were composed of hcg - positive cells , most likely cc , making growing teratoma syndrome unlikely . because gcts with somatic malignancy are usually reported to contain teratoma components and because residual viable cells within the tumors in our case resembled cc and no teratoma component was detected , it is unlikely that the primary mediastinal gct transformed to a somatic type of malignancy . most importantly , despite the enlarged liver lesion in our case , an autopsy showed that almost all tumor cells in the liver had undergone necrosis , and very few resident viable cells remained ( fig . it appeared that the metastatic tumors destroyed the surrounding normal tissues in the liver by inducing necrosis . while no definitive mechanism of this phenomenon can be identified , we offer the following hypothesis : the gct had a malignant phenotype , having cells with the capacity to aggressively invade the outer region , as indicated by mmp-2 expression , leading to enlarged liver lesions . the enlarged liver regions developed a hypoxic environment in the core region , leading to hypoxia - induced central necrosis . in addition , the tumor cells may have released inflammatory molecules or digestive enzymes such as mmp-2 when killed by chemotherapy , which we speculate led to the secondary necrosis of surrounding liver tissues . indeed , total bilirubin and liver enzymes increased rapidly during the 10 days before his death , indicating that cystic lesion expansion caused liver destruction . in this manner , while chemotherapy and central necrosis may have reduced the number of viable tumor cells , which was associated with a decrease in serum hcg levels , the extremely invasive tumor destroyed normal liver structure , eventually leading to the death of the patient . retrospectively , bep successfully reduced the number of viable tumor cells . nevertheless , the efficacy of bep was considered clinically insufficient because the patient 's condition worsened with treatment . in cases where a discrepancy exists between the observed trend of serum tumor markers , imaging studies , and/or the patient 's condition , any decision about whether to switch from bep therapy to salvage chemotherapy will be challenging . in our case , we unfortunately missed the opportunity to administer standard ifosfamide - based salvage chemotherapy because of still decreasing serum hcg levels and the suspicion of infection , only to adopt a less intensive gc regimen on day 31 of bep therapy . for clinicians making important clinical decisions on the best treatment strategies for nsgst , the observation that serum tumor markers for this tumor do not always precisely reflect treatment efficacy should be kept in mind . we report a case of a mediastinal gct which exhibited a discrepancy between the time course of serum tumor markers and the imaging evaluation . we speculate that the extremely invasive tumor destroyed normal liver structure , whereas chemotherapy and central necrosis reduced the number of viable tumor cells themselves , causing a decrease in serum hcg levels . written informed consent was obtained from the patient and his family for publication of this case report and any accompanying images . Output:	we report a mediastinal germ cell tumor ( gct ) that exhibited a discrepancy between the time course of serum human chorionic gonadotropin ( hcg ) levels and clinical consequences . an otherwise healthy man , aged 34 years , was diagnosed with a nonseminomatous gct , most likely embryonal carcinoma ( ec ) , based on a mediastinal tumor biopsy . standard chemotherapy resulted in an optimal decrease in serum hcg levels . however , multiple lesions in the liver continued to enlarge , which led to his death . autopsy revealed few viable tumor cells in the liver , with the great majority of the tumor cells appearing to have undergone necrosis , suggesting that they responded to the chemotherapy . the residual tumor cells in the mediastinum and the liver were similar to syncytiotrophoblast cells , suggesting a cho - riocarcinoma ( cc ) . on immunohistochemical analysis , the mediastinal tumor cells in the diagnostic biopsy specimen expressed both cd30 and hcg , whereas residual mediastinal and hepatic tumor cells in the autopsy specimen after chemotherapy also expressed hcg , but not cd30 . these findings suggested that the patient suffered from a primary mixed gct consisting of an ec and a cc . both pre- and postchemotherapy tumors strongly expressed matrix metalloproteinase-2 , supporting the aggressive and invasive features of the tumor phenotype . we speculate that the extremely invasive tumor destroyed normal liver structure , whereas chemotherapy and central necrosis reduced the number of viable cells themselves , causing a discordant decrease in serum hcg levels .
PubmedSumm118850	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: the neglected disease human african trypanosomiasis ( hat ) , or african sleeping sickness , is caused by two subspecies of the protozoan parasite trypanosoma brucei . if not successfully treated , hat is fatal , and it is estimated to be responsible for about 30000 deaths each year in sub - saharan africa.(1 ) there is no effective vaccine for hat , and the current therapeutics used to treat the disease possess a number of limitations including high toxicity , efficacy against only a single t. brucei subspecies , and the emergence of resistance . undoubtedly , there is an urgent need for the identification and development of new antitrypanosomal compounds . t. brucei and a number of related parasites utilize a redox metabolism based around the dithiol trypanothione [ n , n - bis(glutathionyl)spermidine ] ( figure 1 ) , which is absent in humans.(3 ) therefore , the enzymes involved in this redox pathway are considered to be attractive targets for the development of new antitrypanosomal drugs . one component of the trypanothione - based redox pathway is trypanothione reductase ( tryr , ec 1.8.1.12 ) , an nadph - dependent disulfide oxidoreductase , which is responsible for reducing trypanothione disulfide ( t[s]2 ) to dihydro - trypanothione ( t[sh]2 ) ( figure 1).(3 ) this reduction is analogous to that performed by glutathione reductase ( gr , ec 1.8.1.7 ) in most organisms , including humans . however , the active sites of the two enzymes have opposite net charges , facilitating the development of inhibitors selective for tryr over gr.(6 ) trypanothione provides reducing equivalents either directly or via tryparedoxin for several essential enzymes that protect t. brucei parasites from oxidative damage.(7 ) the tryr - catalyzed reduction of trypanothione disulfide ( t[s]2 ) to dihydrotrypanothione ( t[sh]2 , n , n - bis(glutathionyl)spermidine ) . genetic studies have demonstrated that tryr activity is essential for t. brucei parasites to grow in culture and to be infective in an animal disease model.(8 ) therefore , tryr is a genetically validated drug target , one important criterion in drug target assessment . in addition , tryr inhibitors with diverse core - scaffolds have been reported . however , many of the reported inhibitors are of low potency ( tryr ic50 > 1 m ) , or are not drug - like ( e.g. , mol wt > 500 ) and therefore do not represent suitable starting points for the development of antitrypanosomal drugs . this requirement for high molecular weight compounds to effectively inhibit tryr may in part be a consequence of the large , solvent - exposed trypanothione - binding site of the enzyme.(20 ) although it has been possible to readily identify tryr inhibitor series by both high - throughput and virtual screening , the development of these hits into submicromolar inhibitors has been limited by the lack of crystallographic information required to guide structure - based drug design . none of the proposed tryr inhibitor binding modes derived from docking experiments have been verified by structural techniques and the only high - resolution tryr inhibitor complex that has been reported is that from a covalent adduct between quinacrine mustard and t. cruzi tryr.(26 ) in this current article , we report the synthesis and evaluation of a series of novel t. brucei tryr inhibitors based on the 3,4-dihydroquinazoline core structure ( figure 2 ) . this series was identified from a high - throughput screen against trypanosoma cruzi tryr and subsequently confirmed to also inhibit t. brucei tryr . inhibition data are reported for all analogues against t. brucei tryr and for selected compounds against the parasite in a whole cell assay . the structure activity relationship ( sar ) derived from the in vitro data is discussed . additionally , the key molecular interactions formed between the 3,4-dihydroquinazolines and tryr have been identified by determining the x - ray crystal structure of inhibitors in complex with t. brucei tryr . the liganded structures were used to guide further synthesis , resulting in the preparation of analogues with increased potency against the target enzyme . 3,4-dihydroquinazolines 1a and 1b , small molecule inhibitors of t. cruzi and t. brucei tryr ( see table 1 ) . the general synthetic route used to access the 3,4-dihydroquinazoline analogues is outlined in scheme 1 . this route was based on a modification of a literature route for the preparation of 2-trifluoromethyl-3,4-dihydroquinazolines.(27 ) briefly , substituted 2-aminobenzophenones ( 2a d ) were converted to amides ( 3a d ) by treatment with functionalized acid chlorides . the ketone functionality of 3a d was subsequently reacted with primary amines under microwave irradiation to afford substituted imines ( 4a k , 7a d , 10 , 12 , 14b d , 20 ) . reduction of the imines with nabh4 gave the corresponding secondary amines , from which the 3,4-dihydroquinazolines could be accessed either by reaction with pocl3 or by temperature - assisted cyclization . alternatively , both the imine reduction and cyclization reactions could be achieved in a single pot by treating the imines with nabh4 in refluxing etoh ( scheme 1 ) . this synthetic route proved to be tolerant of a variety of substituents and was used to prepare a number of small compound arrays and individual compounds . reagents and conditions : ( i ) rcocl , dmap , pyridine , ch2cl2 , 25 c , 16 h ; ( ii ) h2n(ch2)nr , etoh , 160 c ( mw ) , 2 h ; ( iii ) nabh4 , dmf , or etoh , 50 c , 16 h ; ( iv ) pocl3 , ch2cl2 , 025 c , 16 h ; ( v ) etoh , 160 c ( mw ) 2 h ; ( vi ) nabh4 , etoh , 78 c , 16 h. to prepare two small collections of substituted amide analogues ( scheme 2 ) the t - boc - protected analogues 11a and 13a were first prepared by following the chemical transformations outlined above ( scheme 1 ) . deprotection of 11a and 13a by treatment with excess hcl , followed by reaction of the resultant amines with a collection of acid chloride building blocks , gave amides 11b h and 13b h , respectively ( scheme 2 ) . reagents and conditions : ( i ) ( 1 ) hcl , dioxane / thf , 25 c , 2 h ; ( 2 ) rcocl , pyridine , ch2cl2 , 40 c , 16 h. variation at the r position required the synthesis of intermediate 5-substituted - benzophenones . where r was halogen ( 15c and 15d ) , this was obtained by regiospecific halogenation of 2-aminobenzophenone(28 ) ( scheme s4 of the supporting information ) . using the 6-bromo derivative ( 15c ) , it was possible to introduce aromatic rings at the 6-position using suzuki chemistry(29 ) ( scheme 3 ) . similarly , reaction of the 8-bromo - derivative 18 under suzuki reaction conditions(29 ) gave the 8-phenyl analogue ( 19 ) ( scheme 3 ) . reagents and conditions : ( i ) ( ho)2b - r , k3po4 , pd(pph3)4 , dioxane / h2o , 120 c ( mw ) , 0.5 h. to further investigate the series , it was necessary to prepare analogues where the substituent r was varied . this required substituted 2-aminobenzophenone starting materials , which were synthesized by three different routes ( scheme 4 ) . following a literature sequence , anthranilate 23 was converted to benzoxazinone 24(30 ) and subsequently reacted with p - tolylmagnesium bromide to give benzophenone 27a in an 18% yield.(31 ) benzophenone 27a was then converted to quinazoline analogue 29a using the general reaction sequence described above . given the poor yield of 27a , an improved two - step synthesis was employed for the preparation of 27b e ( scheme 4 ) . briefly , anthranilate 23 was treated with substituted aryl lithiums followed by tmscl to give the substituted 2-aminobenzophenones 26b e.(32 ) subsequent reaction with accl gave amides 27b e , which were converted to 29b e as outlined in scheme 4 . alternatively , benzophenone analogues could be accessed by reacting grignard reagents with nitrile 25 , followed by hydrolysis of the resultant imine ( scheme 4 ) . this was useful for the preparation of analogues that were not accessible by other routes ( scheme s6 of the supporting information ) . reagents and conditions : ( i ) ac2o , 138 c , 2 h ; ( ii ) ( 1 ) rli , thf , 0 c , 2 h ; ( 2 ) tmscl , 025 c , 15 min ; ( iii ) r mgx , et2o , 025 c , 16 h ; ( iv ) accl , dmap , pyridine , ch2cl2 , 25 c , 16 h ; ( v ) r mgx , thf , 25 c , 30 min , 67 c , 2 h ; ( vi ) h2n(ch2)nch2r , etoh , 160 c ( mw ) , 2 h ; ( vii ) nabh4 , etoh , 78 c , 16 h. the route used to prepare each of 29b f required four dedicated steps from 23 , or 25 making this route unsuitable for the rapid generation of analogues . therefore , a shorter , more suitable route ( scheme 5 ) was developed for the preparation of a small collection of r analogues ( 32a g ) . benzoxazinone 24 was converted into quinazolinone 30 by reaction with 1-(2-aminoethyl)piperidine and subsequent microwave - assisted cyclocondensation.(33 ) reaction of 30 with either substituted phenyl grignard reagents or benzylmagnesium chloride afforded the 4-substituted 3,4-dihydroquinazolin-4-ols 31a h.(34 ) however , the attempted reactions between 30 and cyclohexylmagnesium or cyclopentylmagnesium chloride were unsuccessful , suggesting a limitation in the range of r groups that could be incorporated via this route . benzylic alcohols 31a g were subsequently reduced by treatment with et3sih and bf3oet2 to give the desired 3,4-dihydroquinazolines 32a g . reagents and conditions : ( i ) ( 1 ) 1-(2-aminoethyl)piperidine , ch2cl2 , 25 c , 1 h ; ( 2 ) formamide , 130 c ( mw ) , 10 min ; ( ii ) r mgcl , thf , 025 c , 24 h ; ( iii ) bf3oet , hsiet3 , ch2cl2 , 25 c , 16 h. the two c4 methoxyphenyl analogues ( 32c and 29d ) were converted into the corresponding phenol analogues ( 35 and 36 ) by treatment with bbr3 ( scheme s8 of the supporting information ) . this gave a total of 15 analogues containing different c4 substitutions ( table 5 ) . compounds were assayed against recombinant t. brucei tryr using a spectrophotometric nonenzymatically coupled assay . in this assay , the activity of tyrr is coupled to the reduction of dtnb ( 5,5-dithiobis-(2-nitrobenzoic acid ) ) to 2tnb , which can be measured as an increase in absorbance at 412 nm ( figure s1 of the supporting information ) . the same assay was used to conduct a more detailed kinetic analysis in order to determine the mode of inhibition of selected inhibitors ( see section 2.2 of the supporting information for more details ) . selected compounds were also assayed against bloodstream form t. brucei using the resazurin fluorescence - based cell viability assay(37 ) modified from a previous method.(38 ) in addition , the compounds were assayed using a similar protocol against mrc-5 cells as an indicator of mammalian toxicity . compound 1a was also assayed against human gr using a protocol conceptually similar to the tryr assay . a high - throughput screen of 100000 compounds against t. cruzi tryr identified the 3,4-dihydroquinazolines 1a and 1b ( figure 2 , table 1 ) as low potency inhibitors ( ic50 19 and 38 m , respectively ) . the 3,4-dihydroquinazolines were considered promising screening hits for further investigation due to their low molecular weights ( 373 and 308 ) , reasonable ligand efficiencies ( 0.28 and 0.27 kcal mol per non - h atom , respectively ) , and low polar surface area , an important property due to the requirement for blood brain barrier permeability to treat stage 2 hat . ( as defined here , ligand efficiency = free energy of binding ( g)/number of non - hydrogen ( heavy ) atoms , where g = rtlnkd with r = 1.987 cal k mol ; t = 300 k ; and assuming kd ic50 ( m ) . ) t. cruzi tryr ic50 = 38 m . to determine the validity of this series as a starting point for the development of a lead compound for the treatment of hat , 1a , 1b , and a small collection of commercially available analogues ( 1c n ) were assayed against t. brucei tryr ( table 1 ) . the hit compounds 1a and 1b were found to have ic50 values of 6.8 and 67 m , respectively , confirming their activity against the t. brucei enzyme . the similar levels of activity observed for 1a and 1b against t. cruzi and t. brucei tryr ( < 3-fold difference ) is as expected given the high degree of sequence identity between tryr in the two species ( 83% at the amino acid level overall , 100% for active site residues ) . the remainder of the commercial analogues ( 1c n ) display a range of tryr inhibitory activities ( ic50 9.4 to > 100 m , table 1 ) . although no analogues with improved potency were identified , it was possible to develop a preliminary sar analysis ( figure 3 ) . therefore , the 3,4-dihydroquinazolines represent a validated tryr inhibitor series and a hit expansion program was initiated . sar derived from screening analogues 1a n ( table 1 ) . a more detailed kinetic analysis ( figure s2 of the supporting information ) established that 1a is a linear competitive inhibitor of tryr ( with respect to trypanothione disulfide ) , with a ki value of 0.92 0.06 m , in reasonable agreement with the ic50 value determined in the high - throughput assay ( table 1 ) . therefore , it is possible that the 3,4-dihydroquinazolines are binding to tryr in an orientation that partially occludes the substrate binding pocket . compound 1a is a selective tryr inhibitor because it was inactive against human gr ( ic50 > 100 m ) , the nearest human homologue of tryr . this is consistent with 1a binding to the negatively charged substrate - binding pocket of tryr , in contrast to the positively charged pocket in gr . analogue 1a was assayed against bloodstream form t. brucei and found to have an ec50 of 40 m representing a > 5-fold reduction in potency between the biochemical and cell assay . in a counter - screen against a mammalian cell line ( mrc5 cells ) , screening of commercial analogues demonstrated that the c6-bromine could be replaced with a chlorine atom without a significant loss of activity ( 1a vs 1c , table 1 ) . this beneficial reduction in molecular weight together with the availability of starting material 2a resulted in all further compound arrays consisting of analogues with a c6-chlorine substitution ( except where c6 was the point of variation ) . initial synthesis aimed to identify a replacement for the potentially labile ester functionality of 1c . therefore , benzyl analogues 6a j , amine analogues 9a f , and alcohol - containing analogue 21 were prepared ( table 2 , scheme 1 , and schemes s1 and s2 of the supporting information ) . analogues 6a j , 9a f , and 21 all demonstrated an improved potency with respect to ester 1c in the t. brucei tryr assay , including examples showing a 10-fold improvement ( 6a , 6d , 6 g , and 9c ) . however , there is only a 4-fold difference in potency between the most and least potent analogues in the two arrays ( 6 g vs 6e/9d ) , resulting in a flat sar . to improve potency , a chemistry - driven , systematic sar analysis was performed to investigate the n3- , c4- , c6- , and c8-positions . additional functionality at the c2-position had been shown to result in a large reduction of potency ( 1i1l , table 1 , figure 3 ) , so was not further investigated . to probe the n3-position , amide derivatives of analogues 9f and 9c were prepared ( 11a h and 13a h , scheme 2 and scheme s3 of the supporting information ) . these amides retained their tryr inhibitory activity ( table 3 ) , but there was a narrow range of potencies ( ic50 0.372.6 m ) , giving no identifiable sar . compounds 11e and 13h were found to have a mixed mode of inhibition , although comparison of their ki and ki values show that they bind to the free enzyme more readily than to the enzyme t[s]2 complex , similar to the mode of inhibition of 1a . although more potent , the ligand efficiencies(39 ) of 13e and 13h are poorer than that of 9c ( 0.27 and 0.28 vs 0.31 kcal mol per non - h atom , respectively ) . tryr ki = 0.27 0.02 m , tryr ki = 1.78 0.3 m . when investigating the c6-position ( scheme 3 , table 4 ) , the n3 ester was replaced with a more potent basic moiety ( e.g. , 9a vs 1c ) . the potency of analogues 1a and 15c demonstrated that a bromine atom was tolerated at c6 ( tables 1 and 4 ) . therefore , the c6-position was explored by introducing aryl substituents , prepared as outlined in scheme 3 . the c6-aryl analogues all demonstrated low micromolar tryr ic50 values ( table 4 ) , giving no significant improvement in potency . it was observed that the furan and thiophene analogues ( 16c and 16d ) were 5- to 10-fold more potent than the other c6-aryls ( 16a , b , e , f ) . the fact that analogues containing large bicyclic substitutions at c6 retain some activity ( 16e , f ) suggests that the protein does not entirely occlude the c6 position of the inhibitor upon binding . in addition , the observation that the c6-bromine analogue ( 15c ) is 10-fold more potent than the similarly sized c6-phenyl analogue ( 16a ) implies that the beneficial effect of a bromine substitution is not entirely due to its steric bulk and hydrophobic character . the c8-substituted analogues ( 18 and 19 ) were significantly less active when assayed against tryr ( table 4 ) , suggesting that the introduction of a large hydrophobic group at c8 is detrimental to the inhibitor 's ability to bind to tryr . as the chemistry - driven approach failed to identify inhibitors with improved ligand efficiency , protein crystallographic investigations the sar expanded to include the analogues in tables 24 above is summarized in figure s3 of the supporting information . the x - ray crystal structure for the hit compound 1a in complex with t. brucei tryr was solved and refined at a resolution of 2.8 with an r factor and rfree of 16.4% and 21.9% , respectively ( figure 4a , b , table s1 of the supporting information ) . in addition , the x - ray crystal structures of nonliganded tryr ( 2woi ) , tryr in complex with nadph ( 2wov ) , and tryr in complex with trypanothione dithiol and nadph ( 2wow ) have been determined . ramachandran analyses of the structures show more than 99% of residues are in the allowed regions in all models . the few residues outside these regions correspond to tyr45 , which is known to reside in a strained loop region of all other tryr structures and arg331 , the main chain of which is also held in a strained conformation in some tryr structures . see the supporting information ( sections 3.23.5 ) for a detailed discussion of the comparison between the t. brucei tryr x - ray structures reported in this manuscript and other tryr structures previously reported in the literature . the x - ray protein crystal structure of 1a in complex with t. brucei tryr . ( a ) and ( b ) show two orientations , rotated about 90 , of the tryr compound 1a complex active site showing experimental density ( magenta ) for the inhibitor contoured at 2.5 . compound 1a is shown in blue and fad in turquoise . carbon atoms are shown in brown , oxygens in red , nitrogens in dark blue , and sulfurs in yellow . important residues have been highlighted in black including trp21 and met113 , forming the hydrophobic wall and electron donor glu18 . those residues involved in binding the halogen component are labeled in green , and those involved in the novel hydrophobic pocket are in blue . ( c ) shows the same complex with the solvent accessible surface shown in beige and the ligand in green to demonstrate where the inhibitor is occupying subpockets within the active site cleft . the structure of t[sh]2 ( yellow ) bound to tryr from pdb entry 2wow has been overlaid . examination of the tryr1a complex revealed that the ligand binds in a region of the enzyme s active site cleft that would normally be occupied by the gly - i and spermidine moieties of t[s]2 ( figure 4d ) . therefore , the observed binding mode is consistent with the mode of inhibition of 1a being competitive with respect to t[s]2 as described above . the most interesting feature of the tryr1a structure is the observation that the enzyme undergoes an induced conformational change upon inhibitor binding . this conformational change generates a new subpocket within the active site , which accommodates the c4-phenyl of 1a ( figure 4c ) . previously , the active site of tryr was believed to be a rigid structure,(40 ) formed by residues that belong to a congregation of -helices . accordingly , the substrate t[s]2 is highly flexible and adopts a conformation to accommodate the rigid active site . however , upon binding of 1a , the met113 side chain moves approximately 5 outward into the active site , creating a new hydrophobic pocket . this subpocket is lined by leu120 , phe114 , val33 , leu17 , ala12 , val9 , val31 , and leu48 . the entrance to the subpocket is guarded by trp21 , met113 , and tyr110 . this induced fit had not previously been predicted in tryr , and the significant movement of the met113 side chain clearly changes the properties of the active site , thus affecting the binding of t[s]2 . the bound inhibitor not only sterically impedes the binding of the spermidine moiety of t[s]2 but also alters the shape of the hydrophobic patch that normally binds this substrate moiety . the orientation of 1a in the active site anchors it tightly in position ; the large bromine atom pushes against one end of the cleft and trp21 interacts with the n3 substitution ( see below ) acting as a physical barrier , preventing the inhibitor from locating further up the opposite side of the cleft . there is only one hydrogen bonding interaction with the protein from n1 to the o1 of glu18 ( 2.7 ) . the bromine atom of 1a sits in an area of the active site cleft surrounded by gly13 , ser14 , leu17 , gly49 , val53 , and tyr110 . the catalytic cys52 is situated at this end of this region and sits 6.7 from the c6-bromine . in the nonliganded structure , the area in which the bromine atom binds is instead occupied by a water molecule . the large size of the subpocket around the bromine atom is consistent with analogues 16e and 16f that contain bicyclic aromatic substituents at c6 retaining some , albeit reduced , potency ( ic50 8.0 and 8.5 m , respectively , table 4 ) . the phenyl group sits at an angle of 108 to the plane of the dihydroquinazoline core . in this position , the phenyl group makes an edge face hydrophobic interaction with tyr110 , which has rotated 62 from the nonliganded structure . although one of the weakest hydrophobic interactions,(41 ) it still contributes binding energy to the inhibitor complex . the residues within van der waals interacting distances ( 4 ) from this phenyl group and likely to be participating in hydrophobic interactions include met113 , trp21 , tyr110 , leu17 , phe114 , and leu120 ( figure 4a , b ) . the synthetic routes to substituted dihydroquinazolines that were utilized in this study ( scheme 1 ) result in analogues that are racemic at c4 . however , the ligand binding mode described above allows only the 4s - enantiomer to effectively occupy the induced - fit subpocket created by the movement of met113 . the methyl acetate moiety of 1a is directed out into the active site cleft and sits 3.1 from met113s. it is within 3.5 of , and stacks against , trp21 , which has pivoted about c1 to move the indole group 1.0 closer to the inhibitor when compared to the nonliganded structure . the c2-methyl of 1a also stacks with trp21c1 at a distance of 3 , helping to stabilize the inhibitor in this position . the binding mode of 1a is consistent with 1i1l showing weak or no inhibitory activity ( ic50 89 to > 100 m ) against tryr ( table 1 , figure 3 ) . these analogues contain bulky substitutions at c2 that would prevent ligand binding due to occlusion of this position by the protein . similarly , compounds 18 and 19 ( table 4 ) display reduced potency ( ic50 53 and 24 m , respectively ) due to a steric clash between their c8 substituents and the surface of the active site cleft ( figure 4c ) . , trp21 , and met113 , which form key interactions with 1a , are not conserved in human gr ( see figure s4 of the supporting information ) , which is consistent with the fact that 1a is not an inhibitor of the human enzyme ( see above ) . interestingly , the irreversible tryr inhibitor quinacrine mustard ( figure s7 of the supporting information ) has also been shown to bind to the same hydrophobic area of the protein.(26 ) despite binding in the same region as 1a , the binding of quinacrine mustard does not induce a conformational change in the active site of tryr . a more detailed comparison of the tryr dihydroquinazoline complex with the published tryr quinacrine structures is discussed in section 3.4 of the supporting information . to help rationalize the sar derived from the dihydroquinazoline analogues , additional protein ligand complexes were structurally characterized . to investigate the n3 substitution tryr complexes with analogues 6a , 11e , and comparison of the complexes for compounds 6a , 11e , and 13e with that for 1a show that the 3,4-dihydroquinazoline core superimposes in identical positions and that the c6-halogen substitutions overlay with one another ( figure 5 ) . therefore , the n3 substitution does not have any significant effect on the position of ligand binding . in analogue 6a , the n3 acetyl ester group has been replaced with a benzyl group , resulting in a 10-fold increase in potency ( 6a ic50 = 0.93 m vs 1c ic50 = 9.4 m ) . interestingly , the benzyl group does not stack against trp21 but is angled such that it is pointing away from the side chain of trp21 and into the active site cleft in a similar fashion to the methyl acetate of 1a and so does not appear to contribute to inhibitor binding . in compounds 11e and 13e , the ester moiety has been replaced with substituted amides , giving 11- and 22-fold improvements in potency ( ic50 0.86 and 0.42 m , respectively ) . in 11e and 13e , the n3-substituent runs along the surface of the protein , forming hydrophobic interactions with trp21 and other residues . the displacement of water molecules from the protein surface and the resultant hydrophobic interactions are likely to be the major effect contributing to the improvement in potency observed with these analogues , as there are no other specific molecular interactions between the protein and the additional n3-amide functionality . the lack of specific molecular interactions between tryr and the n3-substituent of 11e/13e is consistent with the relatively flat sar observed from screening 6a j , 9a f , 11a h , and 13a h ( tables 2 and 3 ) . the crystallographically determined binding orientations of compounds 6a , 11e , 13e , and 29a overlaid in the active site of the tryr1a complex structure . 1a is displayed in cyan , 6a in orange , 11e in magenta , 13e in green , and 29a in yellow . the 3,4-dihydroquinazoline and phenyl ring systems overlay well , while the more variable and flexible n3-substituents point out into the active site opening in a variety of orientations . although numerous modeling studies have predicted binding modes for various classes of tryr inhibitors , the accuracy of these models has not been corroborated by structure - based experiments and do not consider the ability of met113 to undergo a conformational change as observed upon binding of 1a . therefore , the current study represents a unique opportunity to perform a validated structure - assisted inhibitor design project for tryr . examination of the tryr ligand structures suggested three primary areas for further investigation : ( 1 ) the effect of altering the halogen substitution at c6 , ( 2 ) challenging the hydrophobic pocket created by the movement of met113 by altering the c4 phenyl moiety , and ( 3 ) reducing the size of the n3 substitution to improve ligand efficiency . d ) ( table 4 ) indicated that they were approximately equipotent . therefore , 3,4-dihydroquinazoline - based inhibitors do not need to occupy the ser14 , leu17 , gly49 , and val63 subpocket ( figure 4a ) to effectively inhibit tryr , providing that 15b binds in an analogous fashion to 1a . to investigate the effect of challenging the induced subpocket with additional steric bulk , compound 29a , containing a para - toluene substituent at c4 , was prepared as outlined in scheme 4 and assayed against tryr ( table 5 ) . the introduction of the additional methyl group resulted in a 4-fold improvement in potency ( cf . 9e , ic50 = 1.0 m , table 2 ) , suggesting that additional hydrophobic interactions in the subpocket are beneficial for ligand binding . structural determination of the tryr29a complex revealed that the overall effect of introducing the methyl group is to push the inhibitor further out into the active site by 0.5 ( figure 5 ) . the c6-chlorine and n1 atoms act as anchor points , having moved only 0.5 , whereas the c4-aryl ring has moved outward by 1.0 toward the mouth of the active site . to accommodate this outward movement , the phenol side chain of tyr110 rotates through 30. the combination of this side chain rotation and inhibitor translation brings the phenyl group of 29a closer to tyr110 by 0.5 when compared to compounds 1a , 6a , 11e , and 13e ( figure 5 ) , allowing stronger hydrophobic stacking interactions to occur . therefore , the 4-fold improvement in potency can be attributed to stronger hydrophobic interactions from occupying more of the subpocket and being closer to tyr110 . a more detailed kinetic analysis of 29a revealed that its mode of inhibition is linear mixed with respect to trypanothione , compared to linear competitive for 1a . however , comparison of the ki and ki values for 29a ( table 5 ) shows that 29a has a greater affinity to the free enzyme than to the enzyme tryr ki = 0.19 0.01 m , ki = 1.46 0.32 m . to further explore the subpocket , a small collection of analogues containing a c4-aryl ( 29b e , 32a g , 35 , and 36 ) , a c4-cyclohexyl ( 29f ) , or a c4-benzyl ( 34 ) substituent were prepared and tested ( table 5 ) . all of the analogues in this collection contained an n - ethylpiperidine substitution at n3 in order to make them directly comparable to the majority of the other dihydroquinazolines prepared in this study . the ortho - substituted analogue 1d was known to be inactive ( table 1 ) , probably due to the additional steric bulk of the ortho - chlorine atom , preventing the c4 substituent from occupying the induced - fit subpocket . therefore , all of the phenyl derivatives were substituted at the meta and/or para positions . however , none of the aryl analogues ( 29b e , 32a c , 32e g , 35 , and 36 ) showed any improvement in potency compared to the para - tolyl analogue 32d ( table 5 ) . increasing the size of the para - substituent to a tert - butyl group ( 29b ) gives an analogue which retains activity , albeit less active than the para - hydrogen analogue ( 9a ) . this suggests that either the induced - fit pocket can accommodate larger hydrophobic groups or that the ligand can bind further away from the top surface of the induced subpocket , although either hypothesis must result in suboptimal ligand binding . this is supported by the observation that the para - methoxy and para - chloro analogues ( 32c and 32a ) are equipotent to 9a . the meta - methoxy analogue 29d is 15-fold less active than 9a , suggesting that the protein can not readily accommodate additional steric bulk in that region of the subpocket . there is no clear relationship between the electronic character of the aryl substituent and tryr inhibitory activity , with the meta - fluoro ( 29c ) and para - fluoro ( 32b ) displaying a 5-fold difference in potency , which can not be attributed to sterics . the 4-cyclohexyl analogue 29f is 15-fold less active than the 4-ph analogue ( 9a ) , consistent with the observation that a 4-aryl substituent contributes to binding affinity by forming an edge three of the 4-oh intermediates on the route to the 3,4-dihydroquinazolines ( 31b d , scheme 5 ) were also assayed against tryr ( table 5 ) and found to retain activity , albeit at a slightly reduced level compared to their reduced counterparts ( 32b d , respectively ) . this is consistent with the observed binding mode of the ligands , which suggests that the additional hydroxyl group would point out into the solvent exposed active site and as a result neither enhance nor impede ligand binding . the sar ( figure s3 of the supporting information ) and tryr ligand complexes suggest that the n3-substituent makes no significant contribution to inhibitor binding . therefore , quinazolines 6k and 21 , which have truncated n3-substituents , were assayed against tryr and found to be equipotent with analogues containing large r - groups ( 6a j , 9a f , table 2 ) . the reduction in substitution size results in compounds with improved ligand efficiencies ( 6k = 0.41 kcal mol per non - h atom ) and reduced polar surface area . selected dihydroquinazoline analogues were screened against both bloodstream form t. brucei parasites and mrc5 cells in whole cell assays ( tables 25 ) . analogues were selected such that representative examples of each array were screened . for the larger arrays , all of the dihydroquinazoline analogues that were screened demonstrated antitrypanosomal activity greater than that for the hit compound ( 1a ) , consistent with them all being more potent tryr inhibitors . however , there is a poor correlation between the tryr ic50 and the t. brucei ec50 , with some analogues ( 9a , 15c , 16a ) having t. brucei ec50 values lower than their corresponding ic50 values . this suggests that some analogues are not exerting all of their antitrypanosomal activity through inhibition of tryr . brucei ec50 ) varies from 1 to 20 , the poor selectivity of some analogues being consistent with off - target activities . it is hoped that , as this series is further optimized against tryr there will be a concomitant reduction in the off - target effects and an increase in selectivity . alternatively , the detailed understanding of the ligand binding mode may facilitate the identification of alternative inhibitor scaffolds with greater selectivity . the nature of the n3-substituent has a large effect upon both the selectivity and t. brucei ec50:tryr ic50 ratio . most analogues which contain a basic n3-functionality ( 9c , e , 11e , h , and 13e , h ) have poor selectivity ( 0.922.3 ) . in addition , the amide - containing analogues ( 11e , h and 13e , h ) display the largest ( > 15-fold ) drop off between their enzyme and cellular inhibition values . however , 9a , which contains an ethylpiperidine n3-substituent , does not follow this trend , instead being 11-fold selective . analogues lacking a basic substitution at n3 ( 1a , 6a , d , g ) show reduced cell activity in both assays , suggesting that overall the amine substituent is increasing off - target activity or is important for cellular uptake . however , although the n3 moiety has an effect upon selectivity and ic50:ec50 ratio within the series , it does not make any significant contributions to tryr binding ( figure 5 ) . compounds 9a , 15c , and 15d , which vary only in their c6-halogen substituent , all display similar activities in all assays ( table 4 ) . however , analogue 15b ( r6 = h ) is 10-fold less potent against t. brucei and as a result significantly less selective . this suggests that the nonspecific antitrypanosomal activity is in part related to the hydrophobicity of the inhibitors ( calculated logd ph 7.4 ; 15b = 2.1 , 15d = 3.2 ) . compound 16a , which contained a c6 phenyl substituent , is 10-fold more potent against t. brucei cells than it is against tryr ( table 4 ) , identifying this inhibitor as acting primarily off - target . in addition , 16a is also one of the most potent analogues in the mrc5 assay . dihydroquinazoline 29a , the most potent analogue against tryr ( ki = 0.19 m , ki = 1.46 m ) , is also one of the most potent against t. brucei ( ec50 = 0.73 m ) , demonstrating that improved tryr potency can drive antitrypanosomal activity . all c4-substituted analogues ( 29a , c , 31d , and 32d ) retain their antitrypanosomal activity ( table 5 cf . 9a ) , in contrast with analogues containing large n3-substitutions ( 11e , h and 13e , h , table 3 ) , despite both sets of compounds having similar tryr inhibitory activities ( tables 3 and 5 ) . the current level of antitrypanosomal activity and selectivity against mammalian cells is insufficient to test these compounds in an animal model of infection . therefore , continued development is required to identify a lead compound from this hit series . large and open active site pockets such as that found in tryr are difficult targets to effectively inhibit with small drug - like molecules . to date , no high - resolution , noncovalent enzyme inhibitor complexes of tryr have been structurally characterized , further limiting attempts to develop potent , low molecular weight inhibitors . in this study , we have reported the crystal structures of t. brucei tryr in complex with a noncovalently bound inhibitor series based around a 3,4-dihydroquinazoline scaffold . in addition , the structure of t. brucei tryr in complex with the cofactors fad , nadph , and reduced trypanothione is presented . the results describe a novel and small hydrophobic pocket generated upon inhibitor binding that lies within a it is anticipated that these results will facilitate the area of tryr inhibitor design and assist in the generation of further protein inhibitor complex structures which until now have relied mainly on in silico modeling and docking studies . given the urgent need for new hat therapeutics , we hope that the structural information reported herein will accelerate the development of tryr inhibitors and possibly identify new drug leads . in addition to the crystallographic studies , we have reported the identification and characterization of a novel tryr inhibitor series based upon the 3,4-dihydroquinazoline ring system . from hit compounds 1a and 1b , a systematic sar study has expanded the series to include > 75 analogues ( tables 15 , figures 3 and 6 , and figure s3 of the supporting information ) . a chemistry - driven approach was used to identify compounds which were more potent than 1a in both the tryr biochemical and t. brucei cell assays ( cf . however , the analogues developed by this strategy contained large n3-substitutions , resulting in high molecular weight inhibitors which were unsuitable for further optimization . the structural elucidation of ligand tryr complexes allowed us to subsequently adopt a structure - based inhibitor design approach , which was used to develop compounds with both improved tryr and t. brucei inhibitory activities ( cf . 1a and 29a , figure 6 ) while maintaining ligand efficiencies > 0.3 kcal mol per non - h atom ( 6k , 29a , figure 6 ) . as the dihydroquinazoline series underwent development , the mode of inhibition changed from competitive to mixed ( cf . 1a and 13h/29a , figure 6 and see figure s2 of the supporting information ) . the development of a mixed inhibitor is potentially advantageous , as these are more resistant to substrate accumulation , a feature that could be important due to the high intracellular concentration of trypanothione . summary of the development of hit compound 1a by an initial chemistry - driven approach and subsequent structure - based inhibitor design strategy . compound 29a is the most potent , drug - like inhibitor of tryr reported to date . however , this series requires further optimization to improve its cellular potency and selectivity . because of their high ligand efficiencies and low molecular weights , analogues 29a and 6k represent good starting points for further structure - based drug design . the hit - to - lead development of the 3,4-dihydroquinazoline inhibitor series is summarized in figure 6 . chemicals and solvents were purchased from the aldrich chemical co. , fluka , abcr , vwr , acros , fisher chemicals , and alfa aesar and were used as received unless otherwise stated . air- and moisture - sensitive reactions were carried out under an inert atmosphere of argon in oven - dried glassware . analytical thin - layer chromatography ( tlc ) was performed on precoated tlc plates ( layer 0.20 mm silica gel 60 with fluorescent indicator uv254 , from merck ) . developed plates were air - dried and analyzed under a uv lamp ( uv254/365 nm ) . flash column chromatography was performed using prepacked silica gel cartridges ( 230400 mesh , 4063 m , from silicycle ) using a teledyne isco combiflash companion , or combiflash retrieve . h nmr , c nmr , f nmr , and 2d - nmr spectra were recorded on a bruker avance dpx 500 spectrometer ( h at 500.1 mhz , c at 125.8 mhz , f at 470.5 mhz ) . chemical shifts ( ) are expressed in ppm recorded using the residual solvent as the internal reference in all cases . signal splitting patterns are described as singlet ( s ) , doublet ( d ) , triplet ( t ) , quartet ( q ) , multiplet ( m ) , broad ( br ) , or a combination thereof . lc - ms analyses were performed with either an agilent hplc 1100 series connected to a bruker daltonics microtof or an agilent technologies 1200 series hplc connected to an agilent technologies 6130 quadrupole lc / ms , where both instruments were connected to an agilent diode array detector . lcms chromatographic separations were conducted with a waters xbridge c18 column , 50 mm 2.1 mm , 3.5 m particle size ; mobile phase , water / acetonitrile + 0.1% hcooh , or water / acetonitrile + 0.1% nh3 ; linear gradient 80:20 to 5:95 over 3.5 min , and then held for 1.5 min ; flow rate 0.5 ml min . all assay compounds had a measured purity of 95% as determined using this analytical lc - ms system ( tic and uv ) . pyridine ( 1.2 equiv ) was added to a solution of the relevant 2-aminobenzophenone analogue , dmap ( cat . ) , and the relevant acid chloride in anhydrous ch2cl2 and stirred at 25 c for 16 h. the reaction mixture was then added to a solution of naoh ( 2.0 m , aq ) , the layers separated , and the aqueous extracted with ch2cl2 . the organic layers were combined , dried over mgso4 , filtered , and the solvent removed under reduced pressure to give the crude amide product . the required amine ( 1.2 equiv ) was added to a solution of the relevant benzophenone analogue in etoh and the reaction mixture heated at 160 c for 1 h in a microwave reactor . nabh4 ( 20 equiv ) was added to a solution of the appropriate imine in anhydrous dmf ( 2 ml ) and heated at 60 c for 16 h. the reaction was then quenched by the addition of water ( 1 ml ) and subsequently extracted into et2o ( 3 5 ml ) . the workup was completed as outlined in method a. note that the amine products were observed to slowly convert to the cyclic amidines when in solution . nabh4 ( 20 equiv ) was added to a solution of the appropriate imine in etoh and heated at 78 c for 1648 h. the reaction was then quenched by the addition of an aqueous solution of citric acid ( 10% w / v ) , the etoh removed under reduced pressure , and the ph of the remaining aqueous adjusted to 10 before being extracted with ch2cl2 . the workup was completed as outlined in method a. pocl3 ( 5 equiv ) was added to a solution of the relevant amine in chcl3 and heated at 61 c for 1624 h. the reaction mixture was added to a solution of naoh ( 2.0 m , aq ) , the layers separated , and the aqueous extracted with ch2cl2 . the workup was completed as outlined in method a. hcl ( 4.0 m in dioxane , 40 equiv ) was added to a solution of boc protected amine 11a or 13a in anhydrous thf and stirred at 25 c for 2.5 h before removal of the solvent under reduced pressure . the crude amine was then redissolved in ch2cl2/pyridine ( 4:1 ) , to which was added dmap ( cat . ) and the relevant benzoyl chloride ( 2 equiv ) . the reaction was subsequently heated at 40 c for 16 h , after which the reaction mixture was added to a solution of naoh ( 2.0 m , aq ) , the layers separated and the aqueous extracted with ch2cl2 . the workup was completed as outlined in method a. pd(pph3)4 ( 0.03 equiv ) was added to a degassed solution consisting of the relevant aryl bromide , the relevant boronic acid , and k3po4 ( 2 equiv ) in dioxane / water ( 10:1 ) . subsequently , the reaction was heated at 120 c for 30 min in a microwave reactor , followed by evaporation of the solvents under reduced pressure . n - buli ( 19.4 mmol , 1.6 m in hexanes , 12.1 ml ) was added to a solution of the relevant aryl bromide ( 17.6 mmol ) in anhydrous et2o ( 20 ml ) at 78 c . subsequently , the reaction was allowed to warm to 0 c over 2 h , after which a solution of 5-chloro anthranilate ( 23 ) ( 4 mmol , 686 mg ) in dry thf ( 30 ml ) was added to the resultant aryl lithium and the reaction stirred for a further 2 h at 0 c . work up was initiated by the addition of tmscl ( 10 ml ) , and the reaction was allowed to warm to 25 c over 15 min . subsequently , 1n hcl ( aq , 30 ml ) was added and the mixture stirred at 25 c for a further 15 min . the biphasic mixture was then separated and the aqueous layer neutralized and extracted into et2o ( 3 50 ml ) . the workup was completed as outlined in method a. the appropriate grignard reagent ( 8 mmol ) was added to a solution of quinazolinone ( 30 ) ( 2 mmol , 612 mg ) in anhydrous thf ( 10 ml ) at 0 c . the reaction was then allowed to warm to 25 c over 2 h before workup was initiated by the addition of nacl solution ( satd aq 20 ml ) . the resultant mixture was filtered and the solids washed with etoac ( 2 10 ml ) . subsequently , the biphasic filtrate was separated and the ph of the aqueous layer adjusted to 10 prior to further extraction with etoac ( 3 50 ml ) . the workup was completed as outlined in method a. bf3oet2 ( 40 equiv ) and hsiet3 ( 40 equiv ) were sequentially added to a solution of the relevant alcohol in ch2cl2 and the reactions stirred at 25 c for 60 h. workup was initiated by the addition of nacl solution ( satd aq ) , the ph of which was adjusted to 10 prior to the layers being separated and the aqueous further extracted with ch2cl2 . the workup was completed as outlined in method a. prepared according to method a from 2-amino-5-chlorobenzophenone ( 2a ) ( 23.2 g , 100 mmol ) and acetyl chloride ( 9.42 g , 120 mmol ) . the crude product was purified by recrystallization from etoac / hexane to give a white solid ( 21.5 g , 79% ) . h nmr ( 500 mhz , cdcl3 ) : 10.63 ( br s , 1h , nh ) , 8.61 ( d , 1h , j = 9.0 hz , h-6 ) , 7.717.69 ( m , 2h , 2 arh ) , 7.667.62 ( m , 1h , arh ) , 7.547.50 ( m , 4h , 4 arh ) , 2.22 ( s , 3h , ch3 ) . c nmr ( 125 mhz , cdcl3 ) : 198.5 ( c ) , 169.2 ( c ) , 138.9 ( c ) , 137.9 ( c ) , 134.0 ( ch ) , 133.1 ( ch ) , 132.6 ( ch ) , 129.9 ( ch ) , 128.6 ( ch ) , 127.3 ( c ) , 124.6 ( c ) , 123.1 ( ch ) , 25.3 ( ch3 ) . lrms ( es+ ) : m / z ( % ) 232 ( 67 ) [ cl m ac + h ] , 234 ( 22 ) [ cl m ac + h ] , 274 ( 100 ) [ cl m + h ] , 276 ( 42 ) [ cl m + h ] . prepared according to method b from benzylamine ( 129 mg , 1.2 mmol ) and n-(2-benzoyl-4-chlorophenyl)acetamide ( 3a ) ( 274 mg , 1 mmol ) in etoh ( 3 ml ) . upon cooling , the product crystallized from the crude reaction mixture and was subsequently recovered by filtration and washed with cold etoh ( 2 5 ml ) to give a white crystalline solid ( 89 mg , 25% ) . h nmr ( 500 mhz , cdcl3 ) : 13.32 ( br s , 1h , nh ) , 8.70 ( d , 1h , j = 9.0 hz , arh ) , 7.597.54 ( m , 3h , 3 arh ) , 7.387.35 ( m , 2h , 2 arh ) , 7.337.28 ( m , 4h , 4 arh ) , 7.237.21 ( m , 2h , 2 arh ) , 6.91 ( d , 1h , j = 2.5 hz , h-3 ) , 4.51 ( s , 2h , ch2 ) , 1.82 ( s , 3h , ch3 ) . c nmr ( 125 mhz , cdcl3 ) : 171.5 ( c ) , 169.6 ( c ) , 139.5 ( c ) , 139.1 ( c ) , 135.3 ( c ) , 132.3 ( ch ) , 131.0 ( ch ) , 129.3 ( ch ) , 129.1 ( ch ) , 128.7 ( ch ) , 128.1 ( ch ) , 127.4 ( ch ) , 126.7 ( c ) , 124.4 ( c ) , 121.8 ( ch ) , 57.9 ( ch2 ) , 25.0 ( ch3 ) . lrms ( es+ ) : m / z ( % ) 363 ( 100 ) [ cl m + h ] , 365 ( 41 ) [ cl m + h ] . prepared according to method c1 from n-(2-((benzylimino)(phenyl)methyl)-4-chlorophenyl)acetamide ( 4a ) ( 109 mg , 0.3 mmol ) . the crude product was purified by flash column chromatography ( etoac / hexane 0:100 50:50 ) to give a cream solid ( 48 mg , 44% ) . h nmr ( 500 mhz , cdcl3 ) : 11.0 ( br s , 1h , nh ) , 8.22 ( d , 1h , j = 8.5 hz , arh ) , 7.327.15 ( m , 10h , 10 arh ) , 7.047.02 ( m , 1h , arh ) , 6.96 ( d , 1h , arh ) , 4.90 ( s , 1h , ch ) , 3.71 ( s , 2h , ch2 ) , 1.98 ( s , 3h , ch3 ) . lrms ( es+ ) : m / z ( % ) 365 ( 100 ) [ cl m + h ] , 367 ( 33 ) [ cl m + h ] . prepared according to method d from n-(2-((benzylamino)(phenyl)methyl)-4-chlorophenyl)acetamide ( 5a ) ( 48 mg , 0.13 mmol ) . the crude product was purified by triturating from et2o ( 40 mg , 87% ) . h nmr ( 500 mhz , cdcl3 ) : 7.69 ( d , 1h , j = 8.5 hz , arh ) , 7.487.42 ( m , 6h , 6 arh ) , 7.277.23 ( m , 3h , 3 arh ) , 7.197.17 ( m , 1h , arh ) , 6.77 ( d , 1h , j = 2.0 hz , h-5 ) , 5.53 ( s , 1h , h-4 ) , 4.89 ( d , 1h , j = 16.0 hz , chh ) , 4.29 ( d , 1h , j = 16.0 hz , chh ) , 2.81 ( s , 3h , ch3 ) . c nmr ( 125 mhz , cdcl3 ) : 158.4 ( c ) , 139.2 ( c ) , 133.1 ( c ) , 131.4 ( c ) 130.2 ( ch ) , 130.1 ( ch ) , 129.91 ( ch ) , 129.88 ( ch ) , 129.5 ( ch ) , 128.2 ( c ) , 127.3 ( ch ) , 126.9 ( ch ) , 126.8 ( ch ) , 122.2 ( c ) , 120.5 ( ch ) , 62.3 ( ch ) , 52.2 ( ch2 ) , 18.5 ( ch3 ) . lrms ( es+ ) : m / z ( % ) 347 ( 100 ) [ cl m + h ] , 349 ( 34 ) [ cl m + h ] . hrms ( es+ ) : calcd for c22h20cln2 [ m + h ] 347.1310 , found 347.1299 ( 3.06 ppm ) . prepared according to method b from 1-(2-aminoethyl)piperidine ( 154 mg , 1.2 mmol ) and n-(2-benzoyl-4-chlorophenyl)acetamide ( 3a ) ( 274 mg , 1 mmol ) . the reaction solvent was removed under reduced pressure and purified by column chromatography ( meoh / ch2cl2 0:100 10:90 ) to give a white solid ( 210 mg , 54% ) . h nmr ( 500 mhz , cdcl3 ) : 13.56 ( br s , 1h , nh ) , 8.72 ( d , 1h , j = 9.0 hz , h-6 ) , 7.517.45 ( m , 3h , 3 arh ) , 7.29 ( dd , 1h , j = 9.0 , 3.0 hz , h-5 ) , 7.127.10 ( m , 2h , 2 arh ) , 6.83 ( d , 1h , j = 3.0 hz , h-3 ) , 3.43 ( t , 2h , j = 7.0 , ch2 ) , 2.66 ( t , 2h , j = 7.0 , ch2 ) , 2.372.28 ( m , 4h , 2 ch2 ) , 2.24 ( s , 3h , ch3 ) , 1.551.51 ( m , 4h , 2 ch2 ) , 1.431.38 ( m , 2h , ch2 ) . c nmr ( 125 mhz , cdcl3 ) : 171.8 ( c ) , 169.6 ( c ) , 139.2 ( c ) , 135.5 ( c ) , 132.1 ( ch ) , 130.8 ( ch ) , 129.1 ( ch ) , 129.0 ( ch ) , 127.1 ( ch ) , 126.6 ( c ) , 124.3 ( c ) , 121.6 ( ch ) , 60.2 ( ch2 ) , 54.8 ( ch2 ) , 51.1 ( ch2 ) , 25.9 ( ch2 ) , 25.5 ( ch3 ) , 24.3 ( ch2 ) . lrms ( es+ ) : m / z ( % ) 192.5 ( 24 ) [ cl m + 2h ] , 384 ( 100 ) [ cl m + h ] , 386 ( 31 ) [ cl m + h ] . prepared according to method c2 or method d. method c2 from n-(4-chloro-2-(phenyl(2-(piperidin-1-yl)ethylimino)methyl)phenyl)acetamide ( 7a ) ( 360 mg , 0.94 mmol ) in etoh ( 5 ml ) : the crude product was purified by flash column chromatography ( 0.5 m nh3 in meoh / ch2cl2 1:100 4:96 ) to give a cream solid ( 211 mg , 61% ) . method d from n-(4-chloro-2-(phenyl(2-(piperidin-1-yl)ethylamino)methyl)phenyl)acetamide ( 8a ) ( 16 mg , 0.04 mmol ) : work up gave a colorless semisolid ( 11 mg , 71% ) that required no further purification . h nmr ( 500 mhz , cdcl3 ) : 7.327.24 ( m , 5h , 5 arh ) , 7.05 ( dd , 1h , j = 8.5 , 2.5 hz , h-7 ) , 6.99 ( d , 1h , j = 8.5 hz , h-8 ) , 6.74 ( d , 1h , j = 2.5 hz , h-5 ) , 5.53 ( s , 1h , h-4 ) , 3.43 ( ddd , 1h , j = 14.5 , 8.5 , 6.0 hz , chh ) , 3.16 ( ddd , 1h , j = 14.5 , 8.5 , 6.0 hz , chh ) , 2.50 ( ddd , 1h , j = 12.5 , 8.5 , 6.0 hz , chh ) , 2.382.28 ( m , 5h , chh eand 2 ch2 ) , 2.26 ( s , 3h , ch3 ) , 1.551.51 ( m , 4h , 2 ch2 ) , 1.431.37 ( m , 2h , ch2 ) . c nmr ( 125 mhz , cdcl3 ) : 156.4 ( c ) , 143.7 ( c ) , 139.6 ( c ) , 129.1 ( ch ) , 128.7 ( c ) , 128.4 ( ch ) , 128.3 ( ch ) , 126.7 ( ch ) , 126.3 ( c ) , 126.0 ( ch ) , 125.0 ( ch ) , 63.2 ( ch ) , 57.4 ( ch2 ) , 55.1 ( ch2 ) , 46.9 ( ch2 ) , 26.0 ( ch2 ) , 24.2 ( ch2 ) , 22.4 ( ch3 ) . lrms ( es+ ) : m / z ( % ) 184.5 ( 88 ) [ cl m + 2h ] , 185.5 ( 35 ) [ cl m + 2h ] , 368 ( 100 ) [ cl m + h ] , 370 ( 35 ) [ cl m + h ] . hrms ( es+ ) : calcd for c22h27cln3 [ m + h ] 368.1888 , found 368.1888 ( 0.01 ppm ) . two identical reactions containing n-(2-benzoyl-4-chlorophenyl)acetamide ( 3a ) ( 1.37 g , 5.0 mmol ) and n - boc-(2-aminoethyl)amine ( 1.19 ml , 7.5 mmol ) in etoh ( 20 ml ) were reacted according to method b. the two reactions were then combined and diluted with etoh ( 60 ml ) and reacted directly according to method c2 . the product was purified by column chromatography ( meoh / ch2cl2 2:98 10:90 ) to give a white solid ( 1.19 g , 30% ) . h nmr ( 500 mhz , cdcl3 ) : 7.337.26 ( m , 5h , 5 arh ) , 7.08 ( dd , 1h , j = 8.5 , 2.0 hz , h-7 ) , 7.05 ( d , 1h , j = 8.5 hz , h-8 ) , 6.76 ( d , 1h , j = 2.0 hz , h-5 ) , 5.44 ( s , 1h , h-4 ) , 3.573.52 ( m , 1h , chh ) , 3.253.14 ( m , 3h , chh and ch2 ) , 2.25 ( s , 3h , ch3 ) , 1.40 ( s , 9h , 3 ch3 ) . c nmr ( 125 mhz , dmso - d6 ) : 156.6 ( c ) , 155.9 ( c ) , 143.3 ( c ) , 129.3 ( ch ) , 129.1 ( c ) , 128.6 ( ch ) , 128.5 ( ch ) , 126.6 ( ch ) , 126.1 ( ch ) , 126.0 ( c ) , 125.0 ( ch ) , 79.9 ( c ) , 62.5 ( ch ) , 48.4 ( ch2 ) , 38.2 ( ch2 ) , 28.3 ( ch3 ) , 22.3 ( ch3 ) . lrms ( es+ ) : m / z ( % ) 400 ( 100 ) [ cl m + h ] , 402 ( 41 ) [ cl m + h ] . hrms ( es+ ) : calcd for c22h27n3o2 [ m + h ] 400.1786 , found 400.1796 ( 2.33 ppm ) . prepared according to method e from tert - butyl 2-(6-chloro-2-methyl-4-phenylquinazolin-3(4h)-yl)ethylcarbamate ( 11a ) ( 120 mg , 0.3 mmol ) and benzoyl chloride ( 84 mg , 0.6 mmol ) . the product was purified by flash column chromatography ( 0.5 m nh3 meoh / ch2cl2 0:100 10:90 ) to give a clear glass ( 53 mg , 44% ) . h nmr ( 500 mhz , cdcl3 ) : 7.687.66 ( m , 2h , 2 arh ) , 7.537.50 ( m , 1h , arh ) , 7.447.41 ( m , 2h , 2 arh ) , 7.367.30 ( m , 5h , 5 arh ) , 7.11 ( dd , 1h , j = 8.5 , 2.5 hz , h-7 ) , 7.06 ( d , 1h , j = 8.5 hz , h-8 ) , 6.78 ( d , 1h , j = 2.5 hz , h-5 ) , 6.27 ( br s , 1h , nh ) , 5.47 ( s , 1h , h-4 ) , 3.683.43 ( m , 4h , 2 ch2 ) , 2.29 ( s , 3h , ch3 ) . c nmr ( 125 mhz , dmso - d6 ) : 168.0 ( c ) , 156.5 ( c ) , 143.6 ( c ) , 139.4 ( c ) , 133.7 ( c ) , 132.0 ( ch ) , 129.3 ( ch ) , 129.2 ( c ) , 128.8 ( ch ) , 128.63 ( ch ) , 128.55 ( ch ) , 126.8 ( ch ) , 126.5 ( ch ) , 126.1 ( c ) , 126.0 ( ch ) , 125.3 ( ch ) , 63.0 ( ch ) , 48.5 ( ch2 ) , 38.3 ( ch2 ) , 22.6 ( ch3 ) . lrms ( es+ ) : m / z ( % ) 404 ( 100 ) [ cl m + h ] , 406 ( 35 ) [ cl m + h ] . hrms ( es+ ) : calcd for c24h23n3o1 [ m + h ] 404.1524 , found 404.1520 ( 1.01 ppm ) . nbs ( 1.87 g , 10.5 mmol ) was added to a suspension of 2-aminobenzophenone ( 1.97 g , 10 mmol ) and tosic acid - derivatized silica gel ( 0.68 mmol / g , 150 mg ) in mecn / et2o ( 1:3 , 50 ml ) . the reaction mixture was stirred for 30 min , filtered , the silica washed with ch2cl2 ( 10 ml ) , and the combined filtrate removed under reduced pressure . the crude aryl bromide was purified by flash column chromatography ( ch2cl2 ) to give a yellow solid ( 2.25 g , 82% ) . h nmr ( 500 mhz , cdcl3 ) : 7.667.64 ( m , 2h , 2 arh ) , 7.607.57 ( m , 2h , 2 arh ) , 7.527.49 ( m , 2h , 2 arh ) , 7.38 ( dd , 1h , j = 8.5 , 2.0 hz , h-4 ) , 6.67 ( d , 1h , j = 8.5 hz , h-3 ) , 6.11 ( br s , 2h , nh2 ) . c nmr ( 125 mhz , cdcl3 ) : 198.0 ( c ) , 149.7 ( c ) , 139.3 ( c ) , 136.9 ( ch ) , 136.2 ( ch ) , 131.6 ( ch ) , 129.1 ( ch ) , 128.4 ( ch ) , 119.4 ( c ) , 118.8 ( ch ) , 106.6 ( c ) . lrms ( es+ ) : m / z ( % ) 276 ( 100 ) [ br m + h ] , 278 ( 100 ) [ br m + h ] . prepared according to method f from 6-bromo-2-methyl-4-phenyl-3-(2-(piperidin-1-yl)ethyl)-3,4-dihydroquinazoline ( 15c ) ( 41 mg , 0.1 mmol ) and phenylboronic acid ( 18 mg , 0.15 mmol ) . the crude product was purified by flash column chromatography ( 0.5 m nh3 ( meoh)/ch2cl2 0:100 10:90 ) to give a brown solid ( 26 mg , 63% ) . h nmr ( 500 mhz , cdcl3 ) : 7.484.46 ( m , 2h , 2 arh ) , 7.407.30 ( m , 7h , 7 arh ) , 7.287.24 ( m , 2h , 2 arh ) , 7.18 ( d , 1h , j = 8.0 hz , arh ) , 7.03 ( d , 1h , j = 2.5 hz , arh ) , 5.65 ( s , 1h , h-4 ) , 3.51 ( ddd , 1h , j = 15.0 , 9.0 , 6.0 hz , chh ) , 3.23 ( ddd , 1h , j = 15.0 , 9.0 , 6.0 hz , chh ) , 2.57 ( ddd , 1h , j = 12.5 , 9.0 , 5.5 hz , chh ) , 2.442.31 ( m , 8h , chh , 2 ch2 , ch3 ) , 1.591.54 ( m , 4h , 2 ch2 ) , 1.461.41 ( m , 2h , ch2 ) . lrms ( es+ ) : m / z ( % ) 410 ( 100 ) [ m + h ] . hrms ( es+ ) : calcd for c28h32n3 [ m + h ] 410.2591 , found 410.2599 ( 2.08 ppm ) . prepared according to general method e from 3-(6-bromo-8-chloro-2-methyl-4-phenylquinazolin-3(4h)-yl)-n , n - dimethylpropan-1-amine ( 18 ) ( 42 mg , 0.1 mmol ) and phenylboronic acid ( 12 mg , 0.1 mmol ) . the crude product was purified by preparative hplc to give a white solid ( 17 mg , 41% ) . h nmr ( 500 mhz , cdcl3 ) : 7.647.62 ( m , 2h , 2 arh ) , 7.417.37 ( m , 2h , 2 arh ) , 7.327.25 ( m , 6h , 6 arh ) , 7.16 ( d , 1h , j = 2.5 hz , arh ) , 6.79 ( dd , 1h , j = 2.5 , 0.5 hz , arh ) , 5.48 ( s , 1h , ch ) , 3.46 ( ddd , 1h , j = 14.5 , 8.5 , 6.0 hz , chh ) , 3.11 ( ddd , 1h , j = 14.5 , 8.5 , 6.0 hz , chh ) , 2.332.22 ( m , 5h , ch2 and ch3 ) , 2.20 ( s , 6h , 2 nch3 ) , 1.821.65 ( m , 2h , ch2 ) . c nmr ( 125 mhz , cdcl3 ) : 156.0 ( c ) , 143.9 ( c ) , 138.7 ( c ) , 137.4 ( c ) , 136.9 ( c ) , 130.5 ( ch ) , 129.5 ( ch ) , 129.1 ( ch ) , 128.3 ( ch ) , 127.7 ( ch ) , 127.4 ( c ) , 127.0 ( ch ) , 126.6 ( ch ) , 125.1 ( ch ) , 62.6 ( ch ) , 56.3 ( ch2 ) , 46.8 ( ch2 ) , 45.4 ( ch3 ) , 26.3 ( ch2 ) , 22.9 ( ch3 ) . [ note : one quaternary carbon resonance is absent , possibly due to it having an identical chemical shift to another quaternary carbon resonance ] . lrms ( es+ ) : m / z ( % ) 209.5 ( 42 ) [ cl m + 2h ] , 210.5 ( 13 ) [ cl m + 2h ] , 418 ( 100 ) [ cl m + h ] , 420 ( 38 ) [ cl m + h ] . hrms ( es+ ) : calcd for c26h29cl1n3 [ m + h ] 418.2045 , found 418.2034 ( 2.54 ppm ) . p - tolylmagnesium bromide ( 1.0 m in thf , 10 ml , 10 mmol ) was slowly added to a solution of benzoxazinone ( 24 ) ( 1.96 g , 10 mmol ) in anhydrous thf ( 40 ml ) at 0 c . the reaction mixture was allowed to warm to 25 c over 30 min and stirred for an additional 1.5 h before the reaction was quenched by the addition of nacl solution ( satd aq 50 ml ) . the resultant biphasic mixture was separated and the aqueous layer extracted with etoac ( 3 50 ml ) . subsequently , the combined organic layers were dried over mgso4 , filtered , and the solvent removed under reduced pressure . the crude product was purified by flash column chromatography over silica ( et2o / hexanes 0:100 50:50 ) to give a white solid ( 511 mg , 18% ) . h nmr ( 500 mhz , cdcl3 ) : 10.54 ( br s , 1h , nh ) , 8.57 ( d , 1h , j = 9.5 hz , arh ) , 7.637.61 ( m , 2h , aabb , 2 arh ) , 7.517.49 ( m , 2h , 2 arh ) , 7.327.30 ( m , 2h , aabb , 2 arh ) , 2.46 ( s , 3h , ch3 ) , 2.21 ( s , 3h , ch3 ) . c nmr ( 125 mhz , cdcl3 ) : 198.0 ( co ) , 169.1 ( c ) , 144.1 ( c ) , 138.7 ( c ) , 135.1 ( c ) , 133.6 ( ch ) , 132.4 ( ch ) , 130.2 ( ch ) , 129.3 ( ch ) , 127.2 ( c ) , 125.0 ( c ) , 123.1 ( ch ) , 25.2 ( ch3 ) , 21.7 ( ch3 ) . lrms ( es+ ) : m / z ( % ) 288 ( 100 ) [ cl m + h ] , 290 ( 31 ) [ cl m + h ] . prepared according to general method b from n-(4-chloro-2-(4-methylbenzoyl)phenyl)acetamide ( 27a ) and 3-(dimethylamino)-1-propylamine . the crude product was purified by flash column chromatography over silica ( 0.5 m nh3 in meoh / chcl3 1:99 4:96 ) to give a white solid ( 485 mg , 65% ) . h nmr ( 500 mhz , cdcl3 ) : 13.66 ( s , 1h , nh ) , 8.71 ( d , 1h , j = 9.0 hz , h-6 ) , 7.297.25 ( m , 3h , aabb and h-5 ) , 6.996.97 ( m , 2h , aabb ) , 6.86 ( d , 1h , j = 2.5 hz , h-3 ) , 3.33 ( t , 2h , j = 7.0 hz , ch2 ) , 2.42 ( s , 3h , ch3 ) , 2.30 ( t , 2h , j = 7.5 hz , ch2 ) , 2.21 ( s , 3h , ch3 ) , 2.19 ( s , 6h , 2 ch3 ) , 1.891.84 ( m , 2h , ch2 ) . c nmr ( 125 mhz , cdcl3 ) : 171.7 ( c ) , 169.3 ( c ) , 139.1 ( c ) , 138.9 ( c ) , 132.4 ( c ) , 132.2 ( ch ) , 130.6 ( ch ) , 129.6 ( ch ) , 127.1 ( ch ) , 126.6 ( c ) , 124.4 ( c ) , 121.5 ( ch ) , 57.7 ( ch2 ) , 51.8 ( ch2 ) , 45.6 ( ch3 ) , 29.7 ( ch2 ) , 25.4 ( ch3 ) , 21.4 ( ch3 ) . lrms ( es+ ) : m / z ( % ) 186.5 ( 100 ) [ cl m + 2h ] , 187.5 ( 32 ) [ cl m + 2h ] , 372 ( 61 ) [ cl m + h ] , 374 ( 18 ) [ cl m + h ] . prepared according to general method c2 from n-(4-chloro-2-((3-(dimethylamino)propylimino)(p - tolyl)methyl)phenyl)acetamide ( 28a ) . the crude product was purified by flash column chromatography over silica ( meoh / ch2cl2 0:100 10:90 ) to give a clear gum ( 99 mg , 28% ) . h nmr ( 500 mhz , cdcl3 ) : 7.207.17 ( m , 2h , aabb,2 arh ) , 7.157.13 ( m , 2h , aabb , 2 arh ) , 7.09 ( dd , 1h , j = 8.5 , 2.5 hz , h-7 ) , 7.05 ( d , 1h , j = 8.5 hz , h-8 ) , 6.77 ( d , 1h . j = 2.5 hz , h-5 ) , 5.46 ( s , 1h , h-4 ) , 3.46 ( ddd , 1h , j = 14.5 , 8.0 , 6.5 hz , chh ) , 3.11 ( ddd , 1h , j = 14.5 , 8.5 , 6.0 hz , chh ) , 2.33 ( s , 3h , ch3 ) , 2.30 ( s , 3h , ch3 ) , 2.292.21 ( m , 2h , ch2 ) , 2.20 ( s , 6h , 2 nch3 ) , 1.811.64 ( m , 2h , ch2 ) . c nmr ( 125 mhz , cdcl3 ) : 156.5 ( c ) , 140.9 ( c ) , 139.8 ( c ) , 138.1 ( c ) , 129.7 ( ch ) , 128.7 ( c ) , 128.2 ( ch ) , 126.6 ( ch ) , 126.5 ( c ) , 126.0 ( ch ) , 125.1 ( ch ) , 62.1 ( ch ) , 56.2 ( ch2 ) , 46.8 ( ch2 ) , 45.4 ( ch3 ) , 26.2 ( ch2 ) , 22.4 ( ch3 ) , 21.1 ( ch3 ) . lrms ( es+ ) : m / z ( % ) 178.5 ( 27 ) [ cl m + 2h ] , 356 ( 100 ) [ cl m + h ] , 358 ( 31 ) [ cl m + h ] . hrms ( es+ ) : calcd for c21h27cl1n3 [ m + h ] 356.1888 , found 356.1881 ( 1.84 ppm ) . prepared according to general method g from 1-bromo-4-(tert - butyl)benzene ( 3.75 g , 17.6 mmol ) . the final product was purified by flash column chromatography over silica ( etoac / hexanes 0:100 50:50 ) to give a yellow solid ( 679 mg , 59% ) . h nmr ( 500 mhz , cdcl3 ) : 7.617.58 ( m , 2h , aabb , 2 arh ) , 7.507.48 ( m , 2h , aabb , 2 arh ) , 7.47 ( d , 1h , j = 2.5 hz , h-6 ) , 7.24 ( dd , 1h , j = 9.0 , 2.5 hz , h-4 ) , 6.69 ( d , 1h , j = 9.0 hz , h-3 ) , 1.37 ( s , 9h , 3 ch3 ) . c nmr ( 125 mhz , cdcl3 ) : 197.8 ( co ) , 155.3 ( c ) , 149.2 ( c ) , 136.4 ( c ) , 133.9 ( ch ) , 133.2 ( ch ) , 129.3 ( ch ) , 125.3 ( ch ) , 120.0 ( c ) , 119.2 ( c ) , 118.4 ( ch ) , 35.1 ( c ) , 31.2 ( ch3 ) . lrms ( es+ ) : m / z ( % ) 288 ( 100 ) [ cl m + h ] , 290 ( 33 ) [ cl m + h ] . prepared in three steps from 26b , acetyl chloride , and 1-(2-aminoethyl)piperidine following general methods a , b , and c2 . the final product was purified by reverse phase preparative hplc to give a white solid ( 40 mg , 6% over 3 steps ) . h nmr ( 500 mhz , cdcl3 ) : 7.337.31 ( m , 2h , aabb ) , 7.217.19 ( m , 2h , aabb ) , 7.07 ( dd , 1h , j = 8.5 , 2.0 hz , h-7 ) , 7.01 ( d , 1h , j = 8.5 hz , h-8 ) , 6.77 ( d , 1h , j = 2.0 hz , h-5 ) , 5.51 ( s , 1h , h-4 ) , 3.45 ( ddd , 1h , j = 14.5 , 8.5 , 6.0 hz , chh ) , 3.20 ( ddd , 1h , j = 14.5 , 8.5 , 6.0 hz , chh ) , 2.52 ( ddd , 1h , j = 13.0 , 8.5 , 6.0 hz , chh ) , 2.402.31 ( m , 5h , chh and 2 ch2 ) , 2.28 ( s , 3h , ch3 ) , 1.581.53 ( m , 4h , 2 ch2 ) , 1.451.40 ( m , 2h , ch2 ) , 1.29 ( s , 9h , 3 ch3 ) . c nmr ( 125 mhz , cdcl3 ) : 156.4 ( c ) , 151.2 ( c ) , 140.9 ( c ) , 139.9 ( c ) , 128.6 ( c ) , 128.2 ( ch ) , 126.5 ( c ) , 126.3 ( ch ) , 126.00 ( ch ) , 125.95 ( ch ) , 125.0 ( ch ) , 62.8 ( ch ) , 57.4 ( ch2 ) , 55.1 ( ch2 ) , 46.9 ( ch2 ) , 34.6 ( c ) , 31.3 ( ch3 ) , 26.0 ( ch2 ) , 24.2 ( ch2 ) , 22.5 ( ch3 ) . lrms ( es+ ) : m / z ( % ) 424 ( 100 ) [ cl m + h ] , 426 ( 34 ) [ cl m + h ] . hrms ( es+ ) : calcd for c26h35cl1n3 [ m + h ] 424.2514 , found 424.2520 ( 1.52 ppm ) . prepared according to general method h using 4-chlorophenylmagnesium bromide ( 1.0 m solution in et2o , 8 ml , 8 mmol ) . the final product was purified by recrystallization from mecn to give a white solid ( 339 mg , 41% ) . h nmr ( 500 mhz , cdcl3 ) : 9.48 ( br s , 1h , oh ) , 7.497.46 ( m , 2h , aabb , 2 arh ) , 7.357.32 ( m , 2h , aabb , 2 arh ) , 7.14 ( dd , 1h , j = 8.5 , 2.5 hz , h-7 ) , 7.11 ( d , 1h , j = 8.5 hz , h-8 ) , 6.79 ( d , 1h , j = 2.5 hz , h-5 ) , 3.513.47 ( m , 1h , chh ) , 3.103.05 ( m , 1h , chh ) , 2.602.55 ( m , 1h , chh ) , 2.502.45 ( m , 2h , 2 chh ) , 2.352.31 ( m , 3 chh and ch3 ) , 1.721.68 ( m , 4h , 2 ch2 ) , 1.541.48 ( m , 2h , ch2 ) . c nmr ( 125 mhz , cdcl3 ) : 153.5 ( c ) , 145.4 ( c ) , 138.2 ( c ) , 133.9 ( c ) , 129.10 ( c ) , 129.08 ( c ) , 128.7 ( ch ) , 128.5 ( ch ) , 128.1 ( ch ) , 127.4 ( ch ) , 125.4 ( ch ) , 85.2 ( c ) , 58.9 ( ch2 ) , 54.6 ( ch2 ) , 43.9 ( ch2 ) , 25.2 ( ch2 ) , 23.6 ( ch2 ) , 23.2 ( ch3 ) . lrms ( es+ ) : m / z ( % ) 418 ( 100 ) [ cl2 m + h ] , 420 ( 64 ) [ cl cl m + h ] . prepared according to general method i from dihydroquinazolinol ( 31a ) ( 42 mg , 0.1 mmol ) . the final product was purified from the crude reaction mixture by flash column chromatography over silica ( meoh / ch2cl2 0:100 10:90 ) to give a clear glass ( 31 mg , 77% ) . h nmr ( 500 mhz , cdcl3 ) : 7.357.33 ( m , 2h , aabb , 2 arh ) , 7.257.22 ( m , 2h , aabb , 2 arh ) , 7.157.11 ( m , 2h , h-7 and h-8 ) , 6.78 ( d , 1h , j = 1.5 hz , h-5 ) , 5.76 ( s , 1h , h-4 ) , 3.52 ( ddd , 1h , j = 15.0 , 6.5 , 6.5 hz , chh ) , 3.293.24 ( m , 1h , chh ) , 2.592.53 ( m , 1h , chh ) , 2.482.26 ( m , 8h , chh , ch3 and 2 ch2 ) , 1.571.53 ( m , 4h , 2 ch2 ) , 1.441.39 ( m , 2h , ch2 ) . c nmr ( 125 mhz , cdcl3 ) : 157.5 ( c ) , 140.7 ( c ) , 135.0 ( c ) , 130.6 ( c ) , 129.70 ( ch ) , 129.2 ( ch ) , 128.2 ( ch ) , 126.2 ( ch ) , 124.4 ( c ) , 122.9 ( ch ) , 62.9 ( ch ) , 57.2 ( ch2 ) , 55.1 ( ch2 ) , 47.3 ( ch2 ) , 26.0 ( ch2 ) , 24.0 ( ch2 ) , 21.0 ( ch3 ) . note : hmbc analysis suggests that the quaternary carbon peak at 135.0 results from two quaternary carbon atoms . lrms ( es+ ) : m / z ( % ) 402 ( 100 ) [ cl2 m + h ] , 404 ( 71 ) [ cl cl m + h ] . hrms ( es+ ) : calcd for c22h26cl2n3 [ m + h ] 402.1498 , found 402.1501 ( 0.62 ppm ) . compounds were assayed against recombinant tryr from t. brucei brucei strain s427 , which was expressed and purified as previously described.(35 ) potency was determined as independent duplicates for all compounds tested as previously . a serial titration of clomipramine was used as a positive control in each assay plate : btcp was used as an additional control in some screening plates . the assay was assessed for robustness , yielding the following typical performance statistics : z = 0.84 0.001 ; % cv ( plate ) = 3.65 0.4 ; s : b = 10 0.25 ; ic50 ( clomipramine ) = 12.4 0.14 m . all reported ic50 values are the mean of at least two replicates , with the standard deviations typically being less than 20% of the mean . compounds were assayed against bloodstream form t. brucei brucei and mrc5 cells using resazurin fluorescence - based viability assays as previously described . all reported ec50 values are the mean of at least two replicates , with the standard deviations typically being less than 50% of the mean . the hat drug pentamidine was present in all t. brucei plates as a positive control . pentamidine has an ec50 of 5 nm ( n > 1000 ) in this assay , which is in close agreement with published ec50 values.(37 ) these were determined as previously described using a dtnb - coupled assay.(12 ) briefly , the assay mixture contained 150 m nadph , 50 m dtnb , and 20 mu ml tryr and was initiated by the addition of t[s]2 ranging from 0.58 to 50 m . the linear rate of increase in absorbance at 412 nm was determined using a molecular devices thermomax plate reader . each data set was fitted by nonlinear regression to the michaelis menten equation using grafit 5.0 ( erithacus software ) . the entire data set was then globally fitted to the appropriate equation ( competitive , mixed , or uncompetitive inhibition ) and goodness - of - fit between models compared using the f - test ( see figure s2 of the supporting information for an example ) . the gene corresponding to t. brucei trypanothione reductase was cloned into a pet15b vector ( novagen ) for overexpression with a 6-histidine tag . the plasmid was transformed into escherichia coli strain bl21 ( de3 ) codon plus ril . the cell pellet was resuspended in 25 mm tris - hcl , ph 8.0 , 500 mm nabr , and 5 mm imidazole and lysed using a french press at 16000 psi . insoluble debris was removed by centrifugation at 40000 g for 20 min and the soluble lysate clarified by filtration through a 0.2 m syringe filter . ni affinity chromatography , thrombin removal of the 6-histidine tag , and q sepharose anion exchange chromatography on an akta purifier ( ge healthcare ) yielded 80 mg l of purified protein as assessed by sds - page . the protein was dialyzed into 50 mm hepes , ph 7.5 , 50 mm nabr , and concentrated to 15 mg ml to be used for crystallography . sparse matrix screens ( jena biosciences ) were used to identify initial crystallization conditions , which were optimized and refined using the hanging drop vapor diffusion method to 26% mpd , 10% polyethylene glycol 3350 , and 40 mm imidazole , ph 8.0 . thin , plate - type crystals grew in 3 days with dimensions 0.3 0.2 0.05 mm . the crystallization mother liquor acted as a suitable cryoprotectant during data collection in which the crystals were cooled to 100 k in a stream of nitrogen gas . for the inhibitor complex structures , crystals were soaked for between 2 and 24 h with solid inhibitor compound introduced into the hanging crystallization drops . data were collected both in - house on a rigaku 007 micromax rotating anode x - ray generator coupled to an r - axis iv++ image plate detector and at the european synchrotron radiation facility on beamlines id142 and id144 . the crystals were space group p21 with cell dimensions of a = 101.8 , b = 63.6 , c = 169.8 , = 97.9. data were processed and scaled using the xds package , and statistics are shown in table s1 of the supporting information . the structure of nonliganded t. brucei tryr was solved by molecular replacement using molrep ( ccp4 ) and the t. cruzi tryr model 1aog(20 ) [ 82% sequence identity ] . matthews coefficient calculations implied that there were two dimers in the asymmetric unit with a solvent content of 51% , which were found by molrep . coot(55 ) was used to correct the nonidentical residues in the tryr model chain a , which was then superposed on chain b , c , and d to generate the two dimers in the asymmetric unit . the nonliganded protein was used as a template to solve the complex structures of the inhibitor series and other ligands in the study . statistics for each of the complex structures are shown in table s1 of the supporting information . compounds were assayed against recombinant tryr from t. brucei brucei strain s427 , which was expressed and purified as previously described.(35 ) potency was determined as independent duplicates for all compounds tested as previously . a serial titration of clomipramine was used as a positive control in each assay plate : btcp was used as an additional control in some screening plates . the assay was assessed for robustness , yielding the following typical performance statistics : z = 0.84 0.001 ; % cv ( plate ) = 3.65 0.4 ; s : b = 10 0.25 ; ic50 ( clomipramine ) = 12.4 0.14 m . all reported ic50 values are the mean of at least two replicates , with the standard deviations typically being less than 20% of the mean . compounds were assayed against bloodstream form t. brucei brucei and mrc5 cells using resazurin fluorescence - based viability assays as previously described . all reported ec50 values are the mean of at least two replicates , with the standard deviations typically being less than 50% of the mean . the hat drug pentamidine was present in all t. brucei plates as a positive control . pentamidine has an ec50 of 5 nm ( n > 1000 ) in this assay , which is in close agreement with published ec50 values.(37 ) these were determined as previously described using a dtnb - coupled assay.(12 ) briefly , the assay mixture contained 150 m nadph , 50 m dtnb , and 20 mu ml tryr and was initiated by the addition of t[s]2 ranging from 0.58 to 50 m . the linear rate of increase in absorbance at 412 nm was determined using a molecular devices thermomax plate reader . each data set was fitted by nonlinear regression to the michaelis menten equation using grafit 5.0 ( erithacus software ) . the entire data set was then globally fitted to the appropriate equation ( competitive , mixed , or uncompetitive inhibition ) and goodness - of - fit between models compared using the f - test ( see figure s2 of the supporting information for an example ) . the gene corresponding to t. brucei trypanothione reductase was cloned into a pet15b vector ( novagen ) for overexpression with a 6-histidine tag . the plasmid was transformed into escherichia coli strain bl21 ( de3 ) codon plus ril . the cell pellet was resuspended in 25 mm tris - hcl , ph 8.0 , 500 mm nabr , and 5 mm imidazole and lysed using a french press at 16000 psi . insoluble debris was removed by centrifugation at 40000 g for 20 min and the soluble lysate clarified by filtration through a 0.2 m syringe filter . ni affinity chromatography , thrombin removal of the 6-histidine tag , and q sepharose anion exchange chromatography on an akta purifier ( ge healthcare ) yielded 80 mg l of purified protein as assessed by sds - page . the protein was dialyzed into 50 mm hepes , ph 7.5 , 50 mm nabr , and concentrated to 15 mg ml to be used for crystallography . sparse matrix screens ( jena biosciences ) were used to identify initial crystallization conditions , which were optimized and refined using the hanging drop vapor diffusion method to 26% mpd , 10% polyethylene glycol 3350 , and 40 mm imidazole , ph 8.0 . thin , plate - type crystals grew in 3 days with dimensions 0.3 0.2 0.05 mm . the crystallization mother liquor acted as a suitable cryoprotectant during data collection in which the crystals were cooled to 100 k in a stream of nitrogen gas . for the inhibitor complex structures , crystals were soaked for between 2 and 24 h with solid inhibitor compound introduced into the hanging crystallization drops . data were collected both in - house on a rigaku 007 micromax rotating anode x - ray generator coupled to an r - axis iv++ image plate detector and at the european synchrotron radiation facility on beamlines id142 and id144 . the crystals were space group p21 with cell dimensions of a = 101.8 , b = 63.6 , c = 169.8 , = 97.9. data were processed and scaled using the xds package , and statistics are shown in table s1 of the supporting information . the structure of nonliganded t. brucei tryr was solved by molecular replacement using molrep ( ccp4 ) and the t. cruzi tryr model 1aog(20 ) [ 82% sequence identity ] . matthews coefficient calculations implied that there were two dimers in the asymmetric unit with a solvent content of 51% , which were found by molrep . coot(55 ) was used to correct the nonidentical residues in the tryr model chain a , which was then superposed on chain b , c , and d to generate the two dimers in the asymmetric unit . the nonliganded protein was used as a template to solve the complex structures of the inhibitor series and other ligands in the study . statistics for each of the complex structures are shown in table s1 of the supporting information . Output:	trypanothione reductase ( tryr ) is a genetically validated drug target in the parasite trypanosoma brucei , the causative agent of human african trypanosomiasis . here we report the discovery , synthesis , and development of a novel series of tryr inhibitors based on a 3,4-dihydroquinazoline scaffold . in addition , a high resolution crystal structure of tryr , alone and in complex with substrates and inhibitors from this series , is presented . this represents the first report of a high resolution complex between a noncovalent ligand and this enzyme . structural studies revealed that upon ligand binding the enzyme undergoes a conformational change to create a new subpocket which is occupied by an aryl group on the ligand . therefore , the inhibitor , in effect , creates its own small binding pocket within the otherwise large , solvent exposed active site . the tryr ligand structure was subsequently used to guide the synthesis of inhibitors , including analogues that challenged the induced subpocket . this resulted in the development of inhibitors with improved potency against both tryr and t. brucei parasites in a whole cell assay .
PubmedSumm118851	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: the natural history of diseases has been elucidated by detailed assessments of enormous amounts of available data . in the management of cancer treatment , there is an expanding movement that overdiagnosis and over - treatment should be eliminated in order to avoid unnecessary treatment - related invasiveness for the patients and to lower medical costs . both active surveillance ( as ) and watchful waiting ( ww ) are accepted policies in several low - risk malignancies , such as prostate cancer , small renal masses , nonseminomatous germ cell tumors of clinical stage i , and papillary thyroid carcinoma . there may be some confusion between as and ww . according to the nci dictionary of cancer terms ( see the website , http://www.cancer.gov/publications/dictionaries/cancer-terms ) , as is defined as ' a treatment plan that involves closely watching a patient 's condition but not giving any treatment unless there are changes in test results that show the condition is getting worse . ' during as , tests and exams such as radiographic evaluation , endoscopic exams , and/or blood / urine tests are performed on a regular schedule . on the other hand , ww is defined as ' closely watching a patient 's condition but not giving treatment unless symptoms appear or change . watchful waiting is sometimes used in conditions that progress slowly . ' during ww , patients may be given certain tests and exams . clinicians need to consider the adverse effects of surgical intervention and nonsurgical treatment such as radiotherapy . the aim of as is to avoid overtreatment or to delay the need for treatment , while there is still a chance for curative intervention when needed during close follow - up in as . urologists are familiar with the concept of as for urogenital malignancies such as low - risk prostate cancer and renal cell masses . although the initial assessment of as for bladder cancer was reported more than 10 years ago , it is still an uncommon option , but it may be ideal in selected patients . the present paper presents the rationale for as for low - risk primary and recurrent nonmuscle invasive bladder cancer ( nmibc ) and reviews the evidence for as for managing this disease . bladder cancer is the sixth most common malignancy in men worldwide , with 297,300 new cases and 112,300 deaths in 2008 . based on the nationwide data of japan , estimated new cases and deaths from bladder cancer in 2013 were 17,461 and 7,299 ( 5,003 men and 2,296 women ) , respectively . most visible bladder tumors are diagnosed by visual inspection under cytoscope , and are confirmed of their grade and stage pathologically by transurethral resection ( turbt ) specimens and radiographically for initial management . approximately 70%80% of urothelial carcinomas are diagnosed as nmibc , consisting of ta ( 70% ) , t1 ( 20% ) , and isolated tis ( 10% ) . the treated natural history of nmibc is characterized by a favorable prognosis ; however , with a high intravesical recurrence rate . nmibc is known to be a heterogeneous disease with different recommended options for treatment and follow - up regimens , and varying oncologic outcomes . up to 70% of patients with nmibcs will experience intravesical recurrences , and 10%30% will progress to life - threatening muscle - invasive bladder cancer ( mibc , t2 ) . however , among nmibcs , low - risk tumors defined as ta low - grade solitary papillary tumors are associated with a favorable cancer - specific survival , along with a lower likelihood of stage and grade progression . the 1- and 5-year recurrence rates range from 15%61% to 31%78% , respectively , while both the 1- and 5-year progression rates are less than 1% . kobayashi et al . reported retrospectively the outcomes of newly diagnosed patients with low - grade ta bladder cancer undergoing initial turbt . in this retrospective study , worsening progression was defined as recurrence with high - grade ta , t1 , or tis / concomitant carcinoma in situ ( cis ) . among 190 cases , 82 ( 43% ) had recurrence and 21 ( 11% ) had worsening progression during follow - up ( median , 101 months ) . considering the treated natural history of nmibc , the quality of turbt and pathologic diagnosis are important factors . the 5-year recurrence - free rate after turbt monotherapy differed across institutions , ranging from 30% to 70% . in addition , the residual cancer rate detected by a second turbt also had a wide range , 20% to 78% , which implies incomplete resection of tumors in initial turbt is common . the quality of turbt is not a negligible factor to minimize the risk of recurrence and progression of nmibc . discrepancies in pathological findings of turbt are also key factors depending on examiners because of their experience as well as artifacts due to cauterization . our previous study demonstrated that general pathologists tend to overdiagnose the specimens of bladder tumors both in stage and grade compared to central uropathologists ( unpublished data ) . experienced urologists have great skills in estimating tumor grade and/or stage by visual appearance on cystoscopy , such as shape , size , and color . a previous report by herr demonstrated that the histology of low - grade ta lesions was able to be predicted with an accuracy of 93% , which was increased to 98% when combined with urine cytology . papillary shaped - bladder tumors have been known to be more indolent than nodular - shaped ones . n - butyl - n-(4-hydroxybutyl ) nitrosamine ( bbn)-induced bladder cancer is one of the most common bladder cancer models . bladder tumors in mice exposed to bbn ad libitum in the drinking water progress through hyperplasia , dysplasia , and cis , and eventually to huge nodular invasive cancers . in contrast , bbn - induced rat bladder cancers are papillary in nature and less aggressive . bladder urothelia in rats treated with bbn develop papillary / nodular hyperplasia after 4 weeks and eventually form papillary tumors through papilloma . bbn - induced urothelial carcinogenesis of the bladder in dogs ( beagle dogs and mongrel dogs ) has been investigated in detail by our colleagues , okajima et al . . when 2 beagles were treated daily with 160 mg of bbn in oral capsules , multifocal papillary g1/g2 tumors were seen 137 weeks after the initiation of bbn treatment . at the time of tumor detection , bbn administration was discontinued and the two beagle dogs were observed without any treatment for over 11 years . pathology revealed papillary nmibc with increased number and size , and small foci of concomitant cis at autopsy . in addition , no distant metastasis was observed . in the bladder cancer models of beagles and rats , the results indicate that these tumors remained papillary nmibc over a long period of time , strongly suggested that the majority of papillary bladder tumors inherently possess little potential to progress to life - threating mibc . this clearly suggests that low - risk papillary bladder cancer is a candidate for an as policy . needless to say , the fundamental goal of treatment of nmibc is the bladder preservation . it consists of turbt with or without intravesical treatment with chemotherapeutic reagents and/or bacille de calmette et gurin . intraoperative and postoperative complications of turbt have been reported previously . in a series of 2,821 patients with 65 years old ( range , 1694 years ) of average age 145 complications ( 5.1% ) were observed . most common ones were bleeding in 78 patients ( 2.8% ) and bladder perforation in 36 ( 1.3% ) requiring open surgery in 4 patients ( 11% ) . bladder perforation occurs more frequently in elderly or female patients who tend to have a thin bladder wall . the true incidence of perforation may be higher , with small perforations that are unrecognized and treated with routine indwelling catheterization without incident . prospective studies have revealed that leakage of contrast media during cystography was detected in more than half of patients undergoing turbt . reported the blood coagulation system disorders ( < 1% ) such as lower - extremity deep vein thrombosis , pulmonary embolism , and acute myocardial infarction , which are known to be potentially life threatening . the authors demonstrated that the incidence of complications correlated with the size and number of tumors , but did not with tumor stage , grade or location . other potential demerit of turbt comprises lower urinary tract symptoms due to the resection and urethral catheterization , which make the bladder susceptible to infection . the repeated extensive resection using electric cautery may cause bladder scarring . in addition , routine cystoscopic examination is also a big issue in the follow - up protocol . the sensitivity of urine cytology is low for the detection of recurrence in low - risk bladder cancers , while cystoscopy is able to detect small recurrent lesions . cystoscopy ( even with flexible scope ) is a discomfort and invasive examination , and has substantial psychological impact to the patients . it potentially causes urethral trauma and subsequent urethral stricture during the long - term follow - up . as to the medical cost , cystoscopy coupled with urine cytology is expensive at outpatient clinic , approximately $ 150 in japan with refer to the exchange rate against us dollar value as of march 2016 . based on the clinical data of the favorable prognosis associated with low - grade ta bladder cancer , there may be no need for immediate turbt or fulguration for primary or recurrent disease . it has been over a decade since soloway et al . presented the initial series of expectant management and reported the feasibility and safety of this concept in patients with low - risk bladder cancer in 2003 . to date , several reports have shown as ( sometimes referred to as expectant management ) for this disease is a reasonable option . table 1 shows the study design and outcomes of as for low - risk bladder cancer . one of the issues may be a lack of optical follow - up protocols regarding the interval between surveillance cystoscopy and the timing of treatment interventions . the initial report of as was a retrospective review of 32 patients with one or more tumors that were visually small , papillary , or low - grade appearing . criteria for turbt were tumor growth or any changes in tumor appearance implying grade and/or stage progression or gross hematuria . during follow - up ( mean , 38 months ) , the mean number of tumor recurrences was 3.8 per patient . of 45 observed tumors that were preceded by tag12 , only three ( 6.7% ) resected by turbt revealed progression to high - grade lesions : high - grade ta in one and t1 in two , while no tumor progressed to mibc . gofrit et al . reported the first homogenous series of low - risk bladder cancer defined by strict inclusion criteria . two years later , the authors updated their series with 31 patients and 43 observation periods at a mean observation follow - up time of 16.1 months . of 4 observation periods , 35 were terminated because of the appearance of additional tumors ( n=15 ) , excessive tumor growth ( n=12 ) , patients ' request ( n=7 ) , and the need for prostatectomy ( n=1 ) . reported two consecutive studies evaluating as for low - risk nmibc in 2009 and 2015 . patients were allocated to as with the criteria similar to the studies by gofrit et al . and low - grade t1 tumors were included . in the largest and most recent study , hernandez et al . evaluated 186 patients ( 252 observation periods ) including 161 men and 25 women with a mean age of 6612 years . during active follow - up including urine cytology plus cystoscopy ( first 2 years ) or urine cytology plus ultrasound test ( thereafter ) , the most frequent reason for termination of as was an increment of lesion number / size , accounting for 178 out of the total 252 observation periods ( 70.6% ) . as a result , 17.1% ( 43 patients ) remained under as for more than 2 years and 8.7% ( 22 patients ) have been under as for more than 3 years . one of the most important issues of as is oncological safety representing no progression in stage and grade . across the surveillance periods , the stage progression - free rate and grade progression - free rate were 86.4% and 79.3% , respectively . progression to t2 was seen in only four patients ; all of them originally had t1g2 tumors . inclusion criteria for as in patients with recurrent low - risk nmibc are refined by gofrit et al . as follows : ( 1 ) previous resection of low - grade ( g12 ) ta tumors ; ( 2 ) no history of previous high - grade ( g3 ) tumors ; ( 3 ) asymptomatic , small ( < 10 mm ) papillary tumor found on routine cystoscopy ; ( 4 ) negative urinary cytology before and during surveillance ; and ( 5 ) patient willingness to participate in the surveillance protocol . however , it is still controversial whether criteria can include t1 tumors or not . the largest study reported by hernndez et al . included the past history of t1 tumors in their criteria . of 252 observation periods , t1g1 tumors and t1g2 tumors account for 25 ( 10% ) and 42 ( 17% ) , respectively . although there was no progression to mibc in 25 t1g1 tumor , but four cases ( 10% ) progressed to mibc in 42 t1g2 tumors . in addition , european association of urology ( eau ) guidelines of nmibc categorize t1 tumors into the high - risk group . these findings imply that a history of t1g2 tumor may not meet the criteria for as . the pathological information including tumor grade , stage and lymphovascular involvement is not available unless turbt or biopsy are performed . recently there are several novel supplementary imaging techniques have been applied in the clinical setting . there is increasing evidence on the usefulness of the enhanced photodynamic imaging , narrow band imaging , optical coherence tomography and confocal laser endomicroscopy , which might be promising aids for cancer detection , disease monitoring and risk stratification . reported the data suggesting high grade and high stage bladder tumors show significantly higher fluorescent intensity compared to low grade and low stage ones . this result implies imaging data or information highly reflect tumor aggressiveness and biology . to date , there has been no report showing the clinical potential of these novel imaging techniques in the patient selection and monitoring during as . another issue in as for bladder cancer is that the follow - up protocol has not been established yet . many previous studies included cystoscopy and urine cytology every 3 months for the first 2 years , every 6 months for the next 3 years , and annually thereafter ( table 1 , summary of standard follow - up protocols ) , which complies with the nmibc guidelines of eau , american urological association , and the national comprehensive cancer network for patients treated with turbt . these follow - up protocols may be too strict in the routine clinical practice for low - risk nmibc . in contrast , the consensus of the socit internationale d'urologie experts indicted that cystoscopy can be skipped for up to 12 months if the first cystoscopy at three months after tur does not detect recurrent tumors . we have conducted a couple of clinical trials to examine the natural history of nmibc including tag12 and t1g2 treated with turbt alone or combined with prophylactic intravesical chemotherapy . in a subanalysis regarding the recurrence detection rate by follow - up cystoscope on the standard protocol , 41 recurrences were observed out of 784 cystoscopic examinations in the tur alone group , and 20 recurrences out of 881 cystoscopic examinations in the epirubicin - treated group during the follow - up period ( table 2 ) . it turned out that number of cystoscope to detect a recurrence was 19.1 times in the control group and 44.1 times in the epirubicin - treated group . as mentioned above , urologists should also bear in mind that cystoscopy is a discomfort , invasive and expensive examination , and have substantial psychological impact to the patients . although papillary low - risk nmibc is characterized by frequent intravesical recurrence and a low potential for disease progression , the intervals between cystoscopy could be delayed or even skipped . in order to advocate as as a standard option in selected patients , a specific follow - up protocol including intervals of cystoscopy , urine cytology , urine markers , and other radiographic exams needs to be validated on the basis of a high level of evidence , so that unnecessary cytoscopic examinations can be avoided . additional parameters estimating the tumor biological behavior are expected in the development of tailor - made follow - up strategies . a recent report assessed the approved urinary tests such as urinary cytology , immunocyt , bta stat , hemoglobin dipstick , and nmp22 bladderchek as potential predictors of recurrence and progression of nmibc . among these five , only nmp22 had an independent prognostic impact on intravesical recurrence and disease progression . because nmp22 is an approved test that is easy to access , this result may be applicable to the clinic . several studies have been carried out to confirm the clinical usefulness of molecular biomarkers for predicting risks . biomarkers such as the ki-67 labeling index , gene mutation of the fibroblast growth factor receptor 3 ( fgfr3 ) , p53 status and chromosomal abnormalities detected by fluorescence in situ hybridization have been reported to be promising molecular tests ; however , there is still a need for them to be validated prior to application to clinical practice . the activated missense mutation of fgfr3 is one of the most frequent gene aberrations in human bladder cancer . among low - grade nmibcs , 50%70% harbor the mutation , whereas it is detected in only 10%20% of high - grade mibcs and cis . these findings support the idea that activated fgfr3 plays critical roles in both carcinogenesis and the cell growth of low - grade nmibc . hernandez et al . reported the largest prospective study to date to investigate the potential of fgfr3 mutation as a prognostic factor for nmibc . the results showed that mutated fgfr3 was associated with a higher risk of intravesical recurrence , but was also associated with a lower risk of disease progression and cancer - specific mortality . an fgfr3 mutation test can be supplementary to determining the optimal follow - up schedule . microrna and genetic alterations detected in the exfoliated urine cells should also be regarded as important auxiliary markers to monitor patients during as . influence of cell growth stimulators such as growth factors and cytokines in urine or tissue are not negligible as urine - based markers . in the meantime , urinary cytology using photodynamic diagnosis is likely to become a novel tool of the as follow - up program . 1 . when peduncular and papillary tumor is found on cystoscopy , as can be recommended to the patient as a one of treatment options . in case of the patient with history of nmibc , it is mandatory that the patients have no past history of high grade tumors , cis or mibc . tumor size , tumor number , and negative urine cytology were included in the criteria for as in most of the previous reports . thus , in the inclusion criteria of the algorithm , tumor size , tumor number and negative urine cytology were included as optional conditions . however , patients for whom urologists hesitate to perform turbt due to high age and severe concomitant diseases would be allocated to ww rather than as . after the patient is allocated to the as program , he or she is followed up at the regular interval with cystoscopy , urine tests and radiographic examinations . interval of cystoscopy depends on the tumor behavior such as tumor size , tumor number and fgfr3 mutation status if available . changes in tumor appearance , occurrence of tumor - related symptom and patient 's request are absolute indications for treatment intervention . tumor growth , increased tumor number , urine cytology and nmp-22 urine test are not included , because they have not been validated and optimized yet . even if patients have a history of allocation to an as program , they can be reallocated repeatedly . as treatment intervention , urologists are intuitively aware that immediate removal is not required in all recurrent tumors such as low - grade ta bladder cancer with an indolent behavior . in spite of considerable evidence supporting as for bladder cancer , follow - up protocols and intervention modalities have not yet been validated at a high level of evidence . however , accumulating data suggest the feasibility , clinical significance , and economic impact of this option . large - scale randomized clinical trials are required to prove the real benefit of as for well - selected patients . similarly , we need to make maximal efforts to obtain significantly reliable biomarkers for as in the urine or sera and to establish monitoring systems . Output:	nonmuscle invasive bladder cancer ( nmibc ) is known to be a heterogeneous malignancy that requires varying treatment modalities and follow - up schedules . low - grade ta papillary tumors are categorized as low - risk nmibc because of their favorable prognosis . there is an expanding movement that overdiagnosis and overtreatment should be avoided considering the economic impact and the patients ' quality of life . it has been over 10 years since the initial assessment of active surveillance for low - risk nmibc suggested its feasibility and safety . however , urologists are still unfamiliar with this treatment option , which can be ideal in appropriately selected patients . in this review article , we focus on active surveillance for low - risk nmibc and discuss the evidence and rationale for this treatment option . there are several issues to resolve in order to advocate active surveillance as a standard option in selected patients . a specific follow - up protocol including intervals of cystoscopy , urine cytology , urine markers , and other radiographic examinations need to be optimized and validated . finally , we integrate the available data into the follow - up strategy and propose a new surveillance protocol for active surveillance of recurrent low - risk bladder cancer .
PubmedSumm118852	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: there are conflicting findings regarding the association between hepatitis b ( hb ) virus ( hbv ) infection and atherosclerosis . ten years previously he had been diagnosed with hbv infection and treated with lamivudine ( 100 mg / day ) . serologic tests revealed that he was positive for hb early antigen , hb surface antigen , and anti - hb core . brain magnetic resonance images were normal , but magnetic resonance angiograms revealed severe stenosis of the right middle cerebral artery , both external carotid arteries , and the basilar artery . this case report reveals that a young patient with reactivated hbv developed multiple arterial stenoses even though he had no risk factors for this disease . hepatitis b ( hb ) virus ( hbv ) infection has generally been used to test the infection - atherosclerosis hypothesis due to several of its characteristics.1 - 3 for example , hbv can cause immune responses and may colonize the vascular tissues . in addition , it can cause thrombotic states , such as obliteration of the small portal and hepatic veins due to phlebitis and thrombosis associated with the disease progression.3,4 however , despite these characteristics , it has been recognized that the findings regarding the association between hbv infection and atherosclerosis are conflicting . furthermore , because previous studies have usually been based on the general population , it is not yet known how atherosclerosis or ischemic stroke is related to hbv infection.5,6 we describe herein a case of multiple cerebral arterial stenoses associated with hbv infection , and discuss the role of hbv infection in the development of atherosclerosis . a 34-year - old man was admitted to our tertiary hospital for transient dysarthria and facial weakness . he had experienced slurred speech , left facial weakness , and dizziness for several hours . his symptoms had completely recovered and he had no neurological abnormalities at admission . there were no vascular risk factors including hypertension , diabetes , hyperlipidemia , smoking , alcohol drinking , or a family history of vascular diseases . ten years previously this patient had been diagnosed with hbv infection and treated with lamivudine ( 100 mg / day ) at a local clinic . six months before admission to our hospital he had suffered abdominal discomfort , nausea , and fatigue , at which time reactivation of hbv was detected . he was seropositive for hb early antigen ( ag ) and hb surface ( hbs ) ag , antibodies against these ags , and hb core antibodies . thereafter , the treatment was changed from lamivudine to entecavir ( 1 mg / day ) . serologic tests performed in our hospital revealed that this patient remained positive for hb early ag , hbs ag , and hb core antibodies . findings of laboratory tests including cholesterol profiles , c - reactive protein , d - dimer , fibrin degradation product , venereal disease research laboratory test , helicobacter pylori ag ( enzyme - linked immunosorbent assay ) , and immunoglobulin m of chlamydia pneumonia were normal . screening tests for autoimmune and coagulation diseases including erythrocyte sedimentation rate , antinuclear antibody , anticardiolipin antibody , rheumatoid factor , lupus anticoagulant , anti - dsdna , anti - ro , anti - la , anti - neutrophilic cytoplasmic antibody , c3 , c4 , prothrombin time , activated partial thromboplastin time , protein - c , protein - s , and antithrombin - iii also produced normal results . brain magnetic resonance ( mr ) images were normal , but mr angiograms revealed severe stenosis of the right middle cerebral artery , both external carotid arteries , and the basilar artery . conventional cerebral angiograms also demonstrated that the patient had eccentric and irregular stenoses in the same arteries ( fig . 1 ) . abdominal and aortic angiograms for differential diagnosis of vasculitis such as takayasu 's arteritis , fibromuscular dysplasia , and/or polyarteritis nodosa ( pan ) yielded normal findings . arterial stiffness was slightly higher compared to the norm for healthy men aged 34 years . the patient was treated with methylprednisolone ( 500 mg / day for 5 days , then tapered and stopped ) , entecavir ( 1 mg / day ) , and combined antiplatelet medication ( aspirin and clopidogrel ) . although transcranial doppler performed 6 months later revealed that there was no improvement in flow velocity at the stenotic arteries , the patient had not developed any ischemic symptoms . this case report reveals that multiple intracranial arterial stenoses were observed in association with hbv reactivation in a young patient without conventional vascular risk factors . the patterns of arterial stenosis and collateral supplies suggested that arterial stenoses develop due to long - standing atherosclerosis . there have been no reports about intracranial arterial stenosis and/or multiple cerebral arterial stenosis associated with hbv infection in young adults . this patient had been taking an antiviral agent when he developed neurological symptoms , which makes antiviral - drug - induced vasculitis a possible cause of this case . however , follow - up transcranial doppler revealed that there was no improvement of flow velocity following appropriate treatment . furthermore , atherosclerosis is usually shown to be eccentric and irregular stenosis.7 our patient had eccentric and irregular stenosis of the middle cerebral artery and basilar artery , and so his atherosclerosis may have been caused by chronic and reactivated hbv infection . we presumed that hbv had recently reactivated and played a role in the progression and destabilization of atherosclerotic plaques in multiple cerebral arteries . first , because hbv is an intracellular organism , it may invade the vascular system.2,8 in order to confirm this hypothesis , pathologic studies that were not available for this case should be performed . a substantial proportion of cases of pan are related to hbv infection.9,10 however , in our case there was no evidence of either pan or any other vasculitis . finally , chronic hbv infection may stimulate inflammatory and immune - mediated responses.11 there was no laboratory evidence in our patient of an immune - mediated response , such as an elevated erythrocyte sedimentation rate . however , because reactivation of hbv infection started 6 months before admission to our hospital , this is a possible mechanism underlying the development of multiple arterial stenoses . the clinical course of chronic hbv infection is characterized by a series of exacerbations and remissions . our patient with multiple arterial stenoses presented with transient dysarthria and facial palsy during the reactivation of hbv . although no baseline mr images were acquired before the hbv reactivation , timely association of the hbv reactivation and the ischemic events led us consider a possible pathogenic link . previous studies have shown that certain infectious agents play an important role in atherogenesis.12,13 however , it is unclear whether atherogenesis is associated with any infection that provokes activation of inflammatory processes or whether only specific organisms play an important role . in addition , some investigators have reported that the activation of an inflammatory process , rather than specific infectious agents , might be responsible for the development of atherosclerotic diseases.14,15 ishizaka et al.5 recently investigated the possible association between hbs ag positivity and carotid arteriosclerosis . in contrast , kiechl et al.14 found no significant association between chronic hepatitis and the presence of carotid atheromatous plaques , but it has also been shown that hbv infection has several features that make it potentially atherogenic.6 these conflicting results6,14 make large population studies necessary for clarification . in conclusion , we describe herein a patient who developed multiple cerebral arterial stenoses associated with hbv infection . this case suggests that patients with hbv infection can develop multiple cerebral arterial stenoses even though they have no risk factors for this disease . however , because there are some conflicting findings , further studies are needed to confirm the association between hbv infection and atherosclerosis . Output:	backgroundthere are conflicting findings regarding the association between hepatitis b ( hb ) virus ( hbv ) infection and atherosclerosis.case reporta 34-year - old man was admitted for transient dysarthria and facial palsy . ten years previously he had been diagnosed with hbv infection and treated with lamivudine ( 100 mg / day ) . reactivation of hbv was detected 6 months before this recent admission . serologic tests revealed that he was positive for hb early antigen , hb surface antigen , and anti - hb core . brain magnetic resonance images were normal , but magnetic resonance angiograms revealed severe stenosis of the right middle cerebral artery , both external carotid arteries , and the basilar artery.conclusionsthis case report reveals that a young patient with reactivated hbv developed multiple arterial stenoses even though he had no risk factors for this disease .
PubmedSumm118853	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: a 48-year - old , previously healthy woman was found to have a subepithelial tumor during health screening endoscopy ( fig . 1a ) . abdominal computed tomography demonstrated a 3.6 2.2 cm , well - defined , solid , enhancing submucosal mass on the posterior wall of the stomach midbody ( fig . there was no further history , symptoms , or signs of systemic disease , and laboratory tests were unremarkable . given a presumptive diagnosis of submucosal neoplasm , wedge resection was performed . grossly , the lesion was a poorly circumscribed , yellowish grey , fusiform mass involving the area from the submucosa to subserosa ( fig . microscopically , the mass showed marked fibrosis , often in a storiform pattern of many lymphoid follicles with well - formed germinal centers , and diffuse inflammatory cell infiltration . the infiltrated inflammatory cells were mainly lymphocytes and plasma cells , but some eosinophils were also found ( fig . there were numerous igg4-positive cells throughout the lesion , and the number of igg4-positive plasma cells was up to 210 per high - power field ( fig . the igg4 to igg - positive cell number ratio was about 85% ; however , there were only a few igg4-positive cells in the mucosa . there was no significant myofibroblastic proliferation or immunostaining for anaplastic lymphoma kinase ; therefore , the possibility of inflammatory myofibroblastic tumor was excluded . the patient s postoperative course was uneventful , and she was discharged without any complications . here , we described a case of isolated gastric igg4-rd presenting as a fusiform mural mass mimicking neoplasm , such as gi stromal tumor or neuroendocrine tumor . to the best of our knowledge , histologically , this case demonstrated all the important features of igg4-rd , including dense lymphoplasmacytic infiltration , storiform fibrosis , obliterative phlebitis , and abundant igg4-positive cells . although other diagnostic criteria , such as elevated serum igg4 level or response to steroid therapy , could not be confirmed due to the clinical presentation , typical histopathologic features led us to consider igg4-rd . increased igg4-positive plasma cells can be seen in other organs and in many conditions , including non - specific chronic inflammation , lymphoma , and other malignancies [ 4,6 - 8 ] . however , these lesions lack other characteristic histopathologic findings , such as storiform fibrosis and oblierative phlebitis , as has been described in the consensus statement on the pathology of igg4-rd . although abundant igg4-positive plasma cell infiltration is not uncommon in the gi tract in the setting of autoimmune pancreatitis , the simple presence of igg4-positive cells does not justify a diagnosis of igg4-rd in the absence of other gross and microscopic features , such as tumefactive nature , storiform fibrosis , and obliterative phlebitis . including the present case , there have been nine cases of massforming igg4-rd in the stomach [ 9 - 14 ] . a case of probable igg4-rd that presented as a gastric ulcer has also been reported , but we excluded this case from the present review . as is summarized in table 1 , most gastric igg4-rd was detected in middle age ( mean , 58.8 years ; range , 45 to 75 years ) , and men and women were affected equally , although the total number of patients is likely too small to reveal any meaningful data . seven patients had solitary nodules or masses , whereas two patients had multiple polyps or nodules . the two patients with multiple lesions also had autoimmune pancreatitis and autoimmune polyendocrinopathy , respectively . four of the seven cases showing a solitary lesion had no sign of multi - organ involvement . most cases of gastric igg4-rd ( six of nine ) involved the submucosal layer of the gastric body . most gastric igg4-rd patients were treated surgically except for one patient with autoimmune pancreatitis who was treated with steroid . steroid treatment is the first therapeutic option in igg4-rd , but all reported isolated gastric igg4-rd cases were surgically resected , presumably because they are rare and difficult to diagnose without pathologic examination of a resected specimen . unnecessary surgery might be avoided if the possibility of igg4-rd is kept in mind and careful pathologic evaluation including igg4 immunostaining is performed on a deep biopsy obtained using endoscopic ultrasonography . Output:	isolated gastric igg4-related disease ( igg4-rd ) is a very rare tumefactive inflammatory condition , with only a few cases reported to date . a 48-year - old woman was incidentally found to have a subepithelial tumor in the stomach . given a presumptive diagnosis of gastrointestinal stromal tumor or neuroendocrine tumor , she underwent wedge resection . the lesion was vaguely nodular and mainly involved the submucosa and proper muscle layer . microscopically , all classical features of type i autoimmune pancreatitis including lymphoplasmacytic infiltration , storiform fibrosis , obliterative phlebitis , and numerous igg4-positive plasma cells were seen . she had no evidence of igg4-rd in other organs . although very rare , igg4-rd should be considered one of the differential diagnoses in the setting of gastric wall thickening or subepithelial mass - like lesion . deep biopsy with awareness of this entity might avoid unnecessary surgical intervention .
PubmedSumm118854	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: the issue of whether to use corticosteroids for treating septic shock has been ongoing for 20 or 30 years . indeed , there is much clinical and preclinical data that provide ample reasons for using corticosteroids in septic shock . for instance , we know that steroids increase catecholamine - stimulated contractility , vasomotor catecholamine response , and adrenergic receptor density . the normal cortisol range is 524 g / dl , and during the stress response this rarely goes above 200 g / dl . during septic shock , classic adrenal insufficiency is rare ( 03% of cases ) and cortisol levels can range from 7 to 400 g / dl . a series of studies has examined the relative adrenal insufficiency that is sometimes seen in septic shock . in one such study patients were stimulated with adrenocorticotrophic hormone ( acth ) and their blood cortisol levels were measured at 0 , 30 , and 60 min . high mortality ( 82% ) was associated with high baseline cortisol levels that did not respond to acth stimulation , whereas low mortality ( 26% ) was associated with low baseline cortisol levels that did respond to acth stimulation . this makes perfect sense and is very logical , which is one of the reasons why i think it has been adopted so quickly even though the data are fairly preliminary and have not been reproduced . a recent study examined a cohort of patients with septic shock , separated them according to the presence or absence of relative adrenal insufficiency , randomized them into a placebo - controlled trial of steroid therapy , and then stratified the analysis according to the adrenal insufficiency variable . at the onset , patients were tested for eligibility using acth stimulation ( although the results of this were not immediately disclosed ) and were then randomly assigned to either hydrocortisone plus a fluorinated steroid or placebo for 7 days , in other words adrenal replacement therapy versus none . the authors found that the group with relative adrenal insufficiency ( by the new criteria ) were observed to have statistically significantly improved survival . this tells us that there is a select population of patients with adrenal insufficiency during septic shock who improve when treated with steroids . in spite of the fact that the responders ( to acth ) did not show a benefit , steroids worked in the group as a whole . the ' take home message ' ought to be that steroids work in septic shock based on the overall study result in all enrolled patients on an intent - to - treat basis . the sticky part is that this population has been studied with steroids many times in the past but without success . so , do cortisol levels predict outcome ? several studies have looked at this : five studies found that nonsurvivors have higher levels of cortisol ; one found that survivors have higher levels ; and three found no correlation . two studies found no correlation with outcome , whereas two other studies found that a small ( inadequate ? ) response predicts death . therefore , as yet there is not enough evidence to state that response to acth is a critically important determinant of outcome . moreover , in those studies , as well as in others , cortisol response is poorly reproducible , even on the same day and in the same patient . thus , even if response to acth were a good measure , it is hard to get reliable clinical data . we know that appropriate levels are not yet known , low random values are difficult to interpret , and the concept of relative adrenal insufficiency is still poorly established . thus , why not study all comers in septic shock , ignoring whether the patient is adrenally insufficient or not ? a study by briegel and colleagues was a double - blind , randomized trial of 40 patients that used the duration of vasopressor therapy as the end - point . the inclusion criterion was patients on vasopressor therapy with a cardiac index greater than 4 , in other words those with vasodilated shock . the treatment was 100 mg hydrocortisone over the first 30 min , and then 0.18 mg / kg per hour for as long as the vasopressor was required . for shock reversal there was no significant difference from the control group ; the median time on vasopressor was different ( but it is not clear what this means because shock reversal showed no difference ) ; and the mortality was identical . in another randomized double - blind study ( this time in 41 patients with septic shock requiring vasopressors for more than 48 hours ) , the end - points were shock reversal , haemodynamics , and survival . there was a statistically significant increase in the number of patients whose shock had reversed by day 7 , and there was a trend toward increased survival , although the numbers were small ( 6 deaths out of 22 in the corticosteroid group and 13 out of 19 in the control group ) . based on those two studies , the acth response does not appear to be necessary to see the shock effect . one interpretation of these data would be that stress steroids was the right approach , whereas high - dose pulse steroid therapy in all patients ( not just adrenal insufficient patients ) with septic shock was the wrong approach . some have stated that steroids might have worked if they had been administered in a less potent way , for instance 100300 mg / day over several days rather than the high doses given in earlier studies , suggesting that replacement of stress levels is what is important this brings us to the study conducted by sprung and colleagues of high - dose hydrocorticosteroids in septic shock . here it was a randomized , prospective trial of 59 patients with septic shock and systolic blood pressure below 90 mmhg after adequate fluids . treatment was industrial strength methylprednisolone 30 mg / kg or dexamethasone 6 mg / kg , and if shock persisted the dose was repeated after 4 hours to a maximum of two doses ( i.e. very short pulse therapy ) . shock reversal occurred more rapidly in the corticosteroid - treated patients than in the control group , and this lasted until day 14 . there was no difference in mortality between the control group and the corticosteroid group at 25 days . therefore , shock was actually improved more rapidly with treatment but mortality was no different . one or two pulses of very high - dose steroids is effective in reversing shock , but with a conflicting effect on mortality . in summary , the pathophysiologic basis for using steroids in septic shock remains very confusing ; the field is plagued by a large number of small trials and there is no doubt that steroids carry risk . thus , if we do not know that something works , then we should not be using it . we do not know who to treat , we do not know when to treat , we do not know the dose to use , and we certainly do not know for how long to maintain treatment . finally , in a meta - analysis of all major studies conducted since 1963 it was shown that the relative risk for death with corticosteroid treatment is slightly increased ; in other words , there is a slight increased risk for death associated with corticosteroids . therefore , the challenge is for us to come up with a study design that can give us a clear idea of what we should be doing in our everyday practice . for now , the data indicate that we should not administer steroids to patients who are in shock . pst received an honorarium from the international sepsis forum for helping to write this commentary . i also thank the international sepsis forum ( isf ) for inviting me to participate in this debate during the society of critical care medicine ( sccm ) annual congress in san diego , usa , in january 2002 . for more information about isf , see . Output:	corticosteroid treatment of severe sepsis has been one of the most controversial clinical issues in critical care . in fact , few agents can claim to have been evaluated in scores of studies spanning 34 decades . yet , convincing proof that corticosteroids are useful pharmacologic agents in the treatment of this major clinical problem remains elusive . recently , interest has resurfaced but this time the focus is on a steroid replacement approach for what has now been termed " relative adrenal insufficiency " rather than relying on the pharmacologic effects of steroids . this route holds promise , but proof remains lacking .
PubmedSumm118855	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: this study was conducted as a sub - study of a population - based prospective cohort study of health , aging , and common geriatric diseases in elderly koreans , and baseline data were collected from september 2005 to august 2006 on residents of seongnam city , south korea . candidates were randomly drawn from a roster of all individuals aged 65 years or older in seongnam city using a computergenerated list of resident registration numbers . a total of 1,118 residents were invited to participate in the study by letter and telephone , of which 696 residents agreed to participate ( a response rate of 62.3% ) . among them , participants with a past history of trauma or surgery around the hand , knee , and hip joints were excluded . finally , the remaining 266 subjects were enrolled , and had completed hand and knee radiographs and bmd measurement . the mean age was 70.8 4.4 years ( range , 65 to 87 years ) , and the study population was composed of 143 men ( 53.8% ) and 123 women ( 46.2% ) . there were no significant differences in the age and body mass index ( bmi ) distribution between the men and women ( table 1 ) . this study was approved by the institutional review board of the authors ' hospital , and informed consent was obtained from all participants . a standard posteroanterior radiograph of the dominant hand was taken for all participants and evaluated for hand oa using a picture archiving and communication system ( impax , impax : agfa , antwerp , belgium ) . fifteen joints of the dominant hand ( 4 distal interphalangeal joints , 4 proximal interphalangeal joints , 5 metacarpophalangeal joints , the first interphalangeal joint , and the first carpometacarpal joint ) were graded from 0 to 4 for oa using the kellgren - lawrence ( k - l ) criteria . according to this grading scale , grade 0 indicates no oa ; grade 1 ( doubtful oa ) , possible osteophytes only ; grade 2 ( minimal oa ) , definite osteophytes and possible cysts ; grade 3 ( moderate oa ) , moderate osteophytes with definite joint space narrowing and some sclerosis ; grade 4 ( severe oa ) , large osteophytes and bony sclerosis with severe joint space narrowing . the worst grade overall among the fifteen joints of the dominant hand was chosen as the radiographic hand oa grade for each participant , and those participants with grade 2 or higher were categorized as having radiographic hand oa . two kinds of radiographs for both knee joints ( a weight bearing anteroposterior radiograph and a posteroanterior radiograph made with the knee in 45 of flexion ) were evaluated for knee the radiographs of each knee were graded separately according to the k - l criteria , and the worse grade of the two was chosen as the radiographic knee oa grade . radiographs were evaluated by two of the authors , who are orthopedic surgeons and were blinded to all other subject information , such as age , sex , bmi , status of the other joints , and the value of bmd . intraobserver reliability was evaluated by having the examiner repeat all radiographic assessments after 3 weeks . the kappa coefficient for the intraobserver reliability was 0.899 ( p = 0.031 ) , and for interobserver reliability was 0.831 ( p = 0.029 ) . thus , the radiographic assessments of only one examiner were used in the analysis , given the high interobserver reliability . femoral neck bmd was measured in the all participants by dual - energy x - ray absorptiometry ( dxa ; ge lunar prodigy , prodigy encore software ver . t - scores were calculated by using the difference between the measured bmd and the mean bmd of healthy young adults matched for sex and ethnicity , divided by the standard deviation ( sd ) of the young adult population . a minimum sample size of 84 participants was required to detect a correlation of greater than r = 0.3 between the t - score of the bmd and the radiographic oa grades of the hand and knee , with a power of 80% ( meaning that the chance that a true correlation would be overlooked is less than 20% ) at a significant level of p < 0.05 . baseline demographic data , such as age and bmi , were compared according to the presence or absence of radiographic oa of the hand and knee using the student t - test . analysis of covariance , adjusting for age and bmi , was performed to compare the bmd according to the presence or absence of radiographic oa of the hand and knee . the adjusted bmd was also compared between those with oa only in the hand , and those with oa only in the knee . partial correlation analysis was performed to evaluate the relationship between the bmd and the radiographic oa grade of the knee and hand , where age and bmi were adjusted for . this study was conducted as a sub - study of a population - based prospective cohort study of health , aging , and common geriatric diseases in elderly koreans , and baseline data were collected from september 2005 to august 2006 on residents of seongnam city , south korea . candidates were randomly drawn from a roster of all individuals aged 65 years or older in seongnam city using a computergenerated list of resident registration numbers . a total of 1,118 residents were invited to participate in the study by letter and telephone , of which 696 residents agreed to participate ( a response rate of 62.3% ) . among them , participants with a past history of trauma or surgery around the hand , knee , and hip joints were excluded . finally , the remaining 266 subjects were enrolled , and had completed hand and knee radiographs and bmd measurement . the mean age was 70.8 4.4 years ( range , 65 to 87 years ) , and the study population was composed of 143 men ( 53.8% ) and 123 women ( 46.2% ) . there were no significant differences in the age and body mass index ( bmi ) distribution between the men and women ( table 1 ) . this study was approved by the institutional review board of the authors ' hospital , and informed consent was obtained from all participants . a standard posteroanterior radiograph of the dominant hand was taken for all participants and evaluated for hand oa using a picture archiving and communication system ( impax , impax : agfa , antwerp , belgium ) . fifteen joints of the dominant hand ( 4 distal interphalangeal joints , 4 proximal interphalangeal joints , 5 metacarpophalangeal joints , the first interphalangeal joint , and the first carpometacarpal joint ) were graded from 0 to 4 for oa using the kellgren - lawrence ( k - l ) criteria . according to this grading scale , grade 0 indicates no oa ; grade 1 ( doubtful oa ) , possible osteophytes only ; grade 2 ( minimal oa ) , definite osteophytes and possible cysts ; grade 3 ( moderate oa ) , moderate osteophytes with definite joint space narrowing and some sclerosis ; grade 4 ( severe oa ) , large osteophytes and bony sclerosis with severe joint space narrowing . the worst grade overall among the fifteen joints of the dominant hand was chosen as the radiographic hand oa grade for each participant , and those participants with grade 2 or higher were categorized as having radiographic hand oa . two kinds of radiographs for both knee joints ( a weight bearing anteroposterior radiograph and a posteroanterior radiograph made with the knee in 45 of flexion ) were evaluated for knee the radiographs of each knee were graded separately according to the k - l criteria , and the worse grade of the two was chosen as the radiographic knee oa grade . radiographs were evaluated by two of the authors , who are orthopedic surgeons and were blinded to all other subject information , such as age , sex , bmi , status of the other joints , and the value of bmd . intraobserver reliability was evaluated by having the examiner repeat all radiographic assessments after 3 weeks . the kappa coefficient for the intraobserver reliability was 0.899 ( p = 0.031 ) , and for interobserver reliability was 0.831 ( p = 0.029 ) . thus , the radiographic assessments of only one examiner were used in the analysis , given the high interobserver reliability . femoral neck bmd was measured in the all participants by dual - energy x - ray absorptiometry ( dxa ; ge lunar prodigy , prodigy encore software ver . 10.50.086 , madison , wi , usa ) . t - scores were calculated by using the difference between the measured bmd and the mean bmd of healthy young adults matched for sex and ethnicity , divided by the standard deviation ( sd ) of the young adult population . a minimum sample size of 84 participants was required to detect a correlation of greater than r = 0.3 between the t - score of the bmd and the radiographic oa grades of the hand and knee , with a power of 80% ( meaning that the chance that a true correlation would be overlooked is less than 20% ) at a significant level of p < 0.05 . baseline demographic data , such as age and bmi , were compared according to the presence or absence of radiographic oa of the hand and knee using the student t - test . analysis of covariance , adjusting for age and bmi , was performed to compare the bmd according to the presence or absence of radiographic oa of the hand and knee . the adjusted bmd was also compared between those with oa only in the hand , and those with oa only in the knee . partial correlation analysis was performed to evaluate the relationship between the bmd and the radiographic oa grade of the knee and hand , where age and bmi were adjusted for . according to the k - l criteria , the oa scores of the hand in the participants were determined at the following frequencies : grade 0 in 0.4% ( 1/266 ) , grade 1 in 39.1% ( 104/266 ) , grade 2 in 45.9% ( 122/266 ) , grade 3 in 11.7% ( 31/266 ) , and grade 4 in 3.0% ( 8/266 ) . the overall prevalence of radiographic hand oa ( k - l criteria 2 ) was 60.5% ( 161/266 ) . it occurred in 56.6% ( 81/143 ) of male participants and 65.0% ( 80/123 ) of female participants , but the difference was not statistically significant ( p = 0.162 ) . oa scores for the knee , according to the k - l criteria , were determined in the following frequencies : grade 0 in 18.8% ( 30/266 ) , grade 1 in 51.1% ( 136/266 ) , grade 2 in 9.4% ( 25/266 ) , grade 3 in 10.9% ( 29/266 ) , and grade 4 in 9.8% ( 26/266 ) . the overall prevalence of radiographic knee oa ( k - l criteria 2 ) was 30.1% ( 80/266 ) . the prevalence was 18.2% ( 26/143 ) in male participants and 43.9% ( 54/123 ) in female participants , which represented a statistically significant difference ( p < 0.001 ) ( table 1 ) . thirty - two percent ( 85/266 ) of participants had neither radiographic hand nor knee oa . thirty - eight percent ( 101/266 ) had radiographic oa only in the hand , and 7.5% ( 20/266 ) had radiographic oa only in the knee . the remaining 22.6% ( 60/266 ) had radiographic oa in both the hand and knee . in male participants , the mean t - score was -0.82 1.01 in those with radiographic hand oa and -0.59 1.06 in those without radiographic hand oa , which had no significant difference after adjustment for age and bmi ( p = 0.717 ) . in female participants , the mean t - score was -1.62 0.87 in those with hand oa and -1.58 0.74 in those without oa , also with no significant difference ( p = 0.862 ) ( table 2 ) . in male participants , the mean t - score was -0.70 1.24 in those with radiographic knee oa and -0.73 0.99 in those without radiographic knee oa , which had no significant difference in the age and bmi adjusted analysis ( p = 0.974 ) . in female participants , the mean t - score was -1.53 0.91 in those with knee oa and -1.67 0.77 in those without oa , also with no significant difference ( p = 0.563 ) ( table 2 ) . in male participants , the mean t - score was -0.86 0.97 in those with radiographic oa only in the hand oa , and -0.63 1.52 in those only in the knee . in female participants , these values were -1.71 0.76 and -1.48 0.67 . there was no significant difference in the mean t scores between those with oa in only one of the locations ( p = 0.920 in male and p = 0.961 in female ) ( table 2 ) . radiographic hand oa grades were not found to be correlated with the t - scores of femoral neck bmd in male participants ( r = -0.113 , p = 0.182 ) nor in female participants ( r = -0.012 , p = 0.897 ) . furthermore , radiographic knee oa grades were not found to be correlated with the t - scores of femoral neck bmd in male participants ( r = 0.098 , p = 0.245 ) nor in female participants ( r = 0.150 , p = 0.098 ) ( table 3 ) . according to the k - l criteria , the oa scores of the hand in the participants were determined at the following frequencies : grade 0 in 0.4% ( 1/266 ) , grade 1 in 39.1% ( 104/266 ) , grade 2 in 45.9% ( 122/266 ) , grade 3 in 11.7% ( 31/266 ) , and grade 4 in 3.0% ( 8/266 ) . the overall prevalence of radiographic hand oa ( k - l criteria 2 ) was 60.5% ( 161/266 ) . it occurred in 56.6% ( 81/143 ) of male participants and 65.0% ( 80/123 ) of female participants , but the difference was not statistically significant ( p = 0.162 ) . oa scores for the knee , according to the k - l criteria , were determined in the following frequencies : grade 0 in 18.8% ( 30/266 ) , grade 1 in 51.1% ( 136/266 ) , grade 2 in 9.4% ( 25/266 ) , grade 3 in 10.9% ( 29/266 ) , and grade 4 in 9.8% ( 26/266 ) . the overall prevalence of radiographic knee oa ( k - l criteria 2 ) was 30.1% ( 80/266 ) . the prevalence was 18.2% ( 26/143 ) in male participants and 43.9% ( 54/123 ) in female participants , which represented a statistically significant difference ( p < 0.001 ) ( table 1 ) . thirty - two percent ( 85/266 ) of participants had neither radiographic hand nor knee oa . thirty - eight percent ( 101/266 ) had radiographic oa only in the hand , and 7.5% ( 20/266 ) had radiographic oa only in the knee . the remaining 22.6% ( 60/266 ) had radiographic oa in both the hand and knee . in male participants , the mean t - score was -0.82 1.01 in those with radiographic hand oa and -0.59 1.06 in those without radiographic hand oa , which had no significant difference after adjustment for age and bmi ( p = 0.717 ) . in female participants , the mean t - score was -1.62 0.87 in those with hand oa and -1.58 0.74 in those without oa , also with no significant difference ( p = 0.862 ) ( table 2 ) . in male participants , the mean t - score was -0.70 1.24 in those with radiographic knee oa and -0.73 0.99 in those without radiographic knee oa , which had no significant difference in the age and bmi adjusted analysis ( p = 0.974 ) . in female participants , the mean t - score was -1.53 0.91 in those with knee oa and -1.67 0.77 in those without oa , also with no significant difference ( p = 0.563 ) ( table 2 ) . in male participants , the mean t - score was -0.86 0.97 in those with radiographic oa only in the hand oa , and -0.63 1.52 in those only in the knee . in female participants , these values were -1.71 0.76 and -1.48 0.67 . there was no significant difference in the mean t scores between those with oa in only one of the locations ( p = 0.920 in male and p = 0.961 in female ) ( table 2 ) . radiographic hand oa grades were not found to be correlated with the t - scores of femoral neck bmd in male participants ( r = -0.113 , p = 0.182 ) nor in female participants ( r = -0.012 , p = 0.897 ) . furthermore , radiographic knee oa grades were not found to be correlated with the t - scores of femoral neck bmd in male participants ( r = 0.098 , p = 0.245 ) nor in female participants ( r = 0.150 , p = 0.098 ) ( table 3 ) . in the present study done on a community - dwelling elderly korean population , we examined the relationship between bmd and oa in the hand and knee . the results of this study indicated that there is no association between bmd and radiographic oa of the hand and knee . our results do not correspond with most of the earlier studies on caucasians , which reported the relationship between osteoporosis and oa . after foss and byers1 ) first reported abnormally high bmd in the forearm of patients with hip oa , this association between high bmd and oa , especially in the hip and knee joints , has been confirmed by several studies.2,3,4,5,7,8 ) regarding hand oa , there have been several contradictory reports about the relationship between osteoporosis and oa.12,13,14,15,16,17,18,19,20 ) for example , a finnish population based cross - sectional and longitudinal study demonstrated that distal interphalangeal and basal joint oa is directly related with low cortical bone mineral mass , in proportion to the severity of oa.16 ) another case - control study indicated that phalangeal bmd is significantly reduced in caucasian women with hand oa , and is related to radiologic severity.18 ) meanwhile , there have been relatively few studies performed in asians.14,19,21,22,23 ) moon and lee23 ) studied 297 korean women with knee osteoarthritis and found that hip bmd and radiographic knee oa were negatively correlated , although the mechanism remains unclear . another study done on 180 korean women with hand joint pain and swelling found that the bmd levels of the distal radius were significantly lower in those with hand oa compared to those of controls.19 ) however , these two studies were done on a hospital - based population.19,23 ) in a study done in 567 community - dwelling japanese women , similar to our study population , the authors reported that appendicular bmd was not associated with oa of the knee , distal interphalangeal and proximal interphalangeal joints , which is consistent with our findings.14 ) although only a few studies are available , we speculate that there may be differences between asians and caucasians , and between hospital - based and community - based populations , which caused the different epidemiologic results . more than half of the participants in this study were male ( 53.8% ) . many studies have focused primarily on women , while relatively few have been performed on men.4,7,13,15,16 ) one epidemiologic study reported that men with hand oa have a higher bmd , while women with hand oa have lower bmd.13 ) another study also suggested that men with hand oa do not lose their bmd , although women with hand oa experience bmd loss over time.15 ) in our study , we could not find such an association between bmd and oa . however , by including the male participants , we believe this study explored the relationship between oa and osteoporosis more comprehensively . in this study , the formation of osteophytes and subchondral bone remodeling occurring near osteoarthritic joints may alter bmd measured around local bones.24 ) spinal bmd measurements were also excluded , because relatively high bmd may be a false measure , caused by the presence of osteophytes , joint space narrowing , and sclerosis in elderly subjects.25,26 ) femoral bmd has been known to be much less affected by osteophytes , because the regions of interest usually studied are distal to the sites of hip joint oa.25 ) moreover , it has been reported that proximal femur bmd measurements consistently outperform lumbar spine measurements for global fracture prediction , which is the most concerning factor in the management of osteoporosis.27,28 ) the strengths of our study are that we analyzed the association between bmd and oa of both weight bearing and non - weight bearing joints simultaneously , focused on aged people including male participants in a community - based population , and measured femoral neck bmd . however , several limitations of the present study should be noted . first , although age and bmi were adjusted as covariates , other possible confounding factors were not included due to the lack of information . hormonal status has been well known as one of the determinants of bmd , especially in elderly women . in addition , degree of physical activity , which might play an important role between osteoporosis and oa , was not adjusted for either . second , although the sample was large enough for correlation analysis between bmd and radiographic oa grade , analysis of covariance for comparison of the bmd according to oa status was under - powered . in comparison of bmd according to hand oa status in male participants , the mean difference of bmd between two groups was 0.23 , and the sds were 1.01 and 1.06 , respectively . as a meaningful difference of mean bmd with a power of 80% , the adequate sample size would be 638 , with 319 subjects in each group . in conclusion , in our cohort of the general korean elderly population , we found no association between osteoporosis and oa , regardless of the weight bearing status of the joints . further studies with a larger population and more relevant variables are required to further examine the relationship between osteoporosis and oa . Output:	backgroundreports on the relationship between osteoporosis and osteoarthritis ( oa ) have tended to disagree , especially in non - weight bearing joints such as the hand joints . we aimed to investigate the relationship between bone mineral density ( bmd ) and hand and knee oa in a general korean elderly population.methodswe evaluated femur neck bmd and the hand and knee radiographs of 143 men and 123 women over 65 years of age who participated in a population - based cohort study . the kellgren - lawrence criteria for grading oa were implemented , and grade 2 or higher were categorized as radiographic oa . bmd was compared according to the existence of radiographic oa in the hand and knee using analysis of covariance , and correlation analyses were performed to explore the relationship between bmd and radiographic oa grade.resultsafter controlling for age and body mass index , there was no significant difference in bmd between participants with and without hand oa ( p = 0.717 in male and p = 0.862 in female ) , between those with and without knee oa ( p = 0.974 in male and p = 0.563 in female ) , and between those with only hand oa and those with only knee oa ( p = 0.920 in male and p = 0.961 in female ) . furthermore , there was no significant correlation between bmd and the radiographic oa grade of the hands ( p = 0.182 in male and p = 0.897 in female ) and knees ( p = 0.245 in male and p = 0.098 in female).conclusionsin our cohort of the general korean elderly population , no association was found between osteoporosis and oa , regardless of the weight bearing status of the joints .
PubmedSumm118856	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: teaching residents to perform cataract surgery is one of the most important and challenging tasks in an ophthalmology training program . since its introduction by howard gimbel in 1991 , four - quadrant divide and conquer has become the standard method for teaching resident surgeons to safely and effectively remove the nucleus during cataract surgery.1,2 to date , only few studies have analyzed other methods of nuclear disassembly for novice surgeons . in this study , the safety and efficiency of teaching pop and chop as an alternative method to divide and conquer to novice resident surgeons were examined . this is a prospective and randomized study of resident cataract surgery using two different techniques of nucleofractis performed at the veterans administration hospital in hampton , virginia . this study was approved by the institutional review boards of the veterans administration hospital and eastern virginia medical school . the first 60 cases performed by two senior residents between july 2014 and december 2015 were randomly assigned to pop and chop or divide and conquer phacoemulsification using a random - number generator . in all the cases , two attending surgeons supervised the divide and conquer cases , whereas a third surgeon assisted with the pop and chop cases . all attending surgeons had 20 years of experience in performing and teaching divide and conquer . the attending surgeon who taught pop and chop had used and taught this method for 10 years . the alcon centurion system for cataract extraction patients with comorbidities such as intraoperative floppy iris syndrome , posterior synechiae , pseudoexfoliation , and previous eye surgery or trauma were excluded from this study . in addition , patients who experienced surgical complications such as vitreous loss , capsular rupture , or zonular dehiscence were also excluded from the analysis . patient demographic data , cumulative dissipated energy ( cde ) , case times , and best corrected postoperative visual acuity were recorded and analyzed for the study cohort . data from 120 cataract surgeries performed by two resident surgeons were examined in this study . in total , 13 cases who met the exclusion criteria were eliminated from the study ( table 1 ) ; six patients were excluded for comorbidities , and seven were excluded for intraoperative complications . of the 107 cases studied , 53 ( 49.5% ) were operated by surgeon 1 and 54 ( 50.5% ) by surgeon 2 ; 54 cases ( 50.5% ) were operated by using divide and conquer , whereas the remaining 53 cases ( 49.5% ) were operated by using pop and chop . demographic data such as age , race , and sex were similar in these two groups ( table 2 ) . figure 1 shows the analysis of cde data of each surgeon separately and for the total samples included in this study . surgeon 1 had an average cde of 15.0 ( 95% confidence interval [ ci ] = 11.819.2 ) for the divide and conquer method and 11.1 ( 95% ci = 8.714.2 ) for the pop and chop method ; this difference was not statistically significant ( p=0.0888 ) . surgeon 2 had an average cde of 16.7 ( 95% ci = 12.123.1 ) for the divide and conquer method and 6.1 ( 95% ci = 4.48.5 ) for the pop and chop method ; this difference was statistically significant ( p0.0001 ) . when the data of both the surgeons were combined together , the average cde was 15.9 ( 95% ci = 12.919.6 ) for the divide and conquer method and 8.6 ( 95% ci = 7.010.7 ) for the pop and chop method ; this difference was statistically significant ( p0.001 ) . figure 2 shows the analysis of case time data of each surgeon separately and for the total samples included in this study . on average , case times for surgeon 1 were 27.8 minutes ( 95% ci = 24.931.0 ) for the divide and conquer method and 15.0 minutes ( 95% ci = 13.416.7 ) for the pop and chop method ; this difference was statistically significant ( p0.0001 ) . case times for surgeon 2 were 34.4 minutes ( 95% ci = 30.039.4 ) for the divide and conquer method and 20.5 minutes ( 95% ci = 17.923.5 ) for the pop and chop method ; this difference was statistically significant ( p0.0001 ) . when the data of both the surgeons were combined together , the average case time was 31.1 minutes ( 95% ci = 28.334.2 ) for the divide and conquer method and 17.8 minutes ( 95% ci = 16.219.6 ) for the pop and chop method ; this difference was statistically significant ( p0.0001 ) . final best corrected visual acuity of 20/40 was achieved in 90% of patients in the pop and chop group and 95% in the divide and conquer group . after excluding patients with preexisting retinal pathologies ( five had age - related macular degeneration and one had a macular hole ) , 100% of patients in the pop and chop group and 99% of the patients in the divide and conquer group achieved 20/40 or better vision ( figure 3 ) . intraoperative complications occurred in four ( 7.5% ) pop and chop cases and three ( 5.6% ) divide and conquer cases . these cases had two posterior capsular tears and two zonular dehiscences with pop and chop method and three posterior capsular tears with divide and conquer method . pop and chop is a supracapsular method of nuclear chopping initially described by pandit and oetting.3 in this technique , nucleus is partially prolapsed out of the capsular bag during hydrodissection and then divided between the phaco tip and a second instrument into heminuclei or quadrants that can easily be removed by phaco - assisted aspiration in the pupillary plane or anterior chamber . because nuclear fragmentation is performed under direct visualization above the capsular bag , it is easier to learn and perform than endocapsular chopping techniques that require significant surgical experience and skill.4 in a retrospective chart review comparing pop and chop with divide and conquer , parlitsis et al concluded that both the techniques are appropriate for resident surgeons and noted no significant differences in visual outcomes or complication rates.5 in the present study , the safety and efficacy of teaching pop and chop to resident surgeons were confirmed . in addition , we report that pop and chop is a significantly more efficient surgical technique than divide and conquer , which requires lesser phaco energy and surgical time than divide and conquer when performed early in residency training . supranuclear methods of nucleofractis have used lesser energy than divide and conquer when performed by experienced surgeons.6,7 a variety of supranuclear techniques have been described , which may be appropriate to teach to resident surgeons . these include davis and lindstrom s tilt and tumble , pandit and oetting s pop and chop , and starr s pop and prechop.3,8,9 in a retrospective study of cataract surgery performed by trainees , starr reported significantly lower levels of energy utilization , resulting in better corneal clarity scores using his pop and prechop technique.8 similarly , the present study found that significant reductions in phaco energy could be achieved by novice resident surgeons performing pop and chop in their first 60 cases . in this study , pop and chop cases were all supervised by a single attending surgeon because he has greater familiarity with this technique and greater experience in teaching it to novice surgeons . a previous publication reported low and zero cde phaco in resident cases using the pop and chop technique performed under the supervision of that and other attending surgeons.10 in several studies , it is found that lower energy has been associated with improved outcomes.68,11 further studies are required to show whether the lower energy levels that we observed while using pop and chop will produce improved surgical outcomes in resident cataract surgery . the results from this study also clearly demonstrate that pop and chop is significantly faster than divide and conquer when performed by resident surgeons . shorter case times have been reported to be associated with less endothelial cell loss and fewer surgical complications.6,11 on average , it was found that case time was 27.8 minutes ( 95% ci = 24.931.0 ) for the divide and conquer method and 15.0 minutes ( 95% ci = 13.416.7 ) for the pop and chop method . in a previous study on resident cataract surgery , hosler et al reported that resident case times improved from an average of 63 minutes at the beginning of the academic year to 27 minutes at the end of the academic year.12 in the present study , although surgical cases were observed early in training , the average case times were clearly reduced by the exclusion of complicated and difficult cases . however , based on the data from both the studies , a case time of ~30 minutes could be used as a reasonable goal for resident surgeons for performing uncomplicated cases of divide and conquer . in addition , goals for shorter case times could be reasonable when using supranuclear chopping techniques . from the present study , it was found that the shorter case times that were observed with pop and chop suggest that novice residents can quickly master this technique with measurable advantages in surgical efficiency in their first 60 cases . in this study , the overall rate of intraoperative complications was 5.6% with divide and conquer and 7.5% with pop and chop in the first 60 cases performed by two resident surgeons . these values are consistent with the results of previous studies that report rates of vitreous loss in resident cases ranging from 6% to 15%.13,14 randleman et al reported that the complication rate in resident cases clearly decreases after the first 80 cases and continues to decline as residents gain more experience.2 although the present study observed cases early in residency training , based on the data obtained , it was concluded that pop and chop seems to be as safe as divide and conquer for novice surgeons . in a study on more experienced trainees performing pop and prechop , christopher starr found a significantly lower rate of vitreous loss ( 0.9% ) and concluded that supranuclear chopping is safer than endocapsular cracking or chopping for novice surgeons.8 further studies comparing these nucleofractis techniques over the course of an entire residency year would be beneficial to confirm this hypothesis . the present study demonstrated that pop and chop is safe to be taught to novice resident surgeons as an initial method of nuclear disassembly . this technique is faster and uses less energy than divide and conquer in early residency training . in addition , the data from this study suggest that the learning curve for this procedure is short , which allows residents to achieve proficiency in performing this quickly . further studies are required to better define the role of this technique in residency education . Output:	in this randomized prospective study , the cumulative dissipated energy and case time of pop and chop and of traditional four - quadrant divide and conquer in the first 60 cases ( in total 120 eyes ) of cataract surgery performed by two residents at the veterans administration hospital in hampton , virginia , were compared . overall and individually , the residents had significantly shorter case times and used significantly less cumulative dissipated energy for performing pop and chop than that for divide and conquer technique . there was no difference in complication rates or visual outcomes between these two techniques . the results of this study suggest that pop and chop is a more time- and energy - efficient method of nucleofractis than divide and conquer for novice resident surgeons .
PubmedSumm118857	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: it is well known that patients with legionella pneumonia present with multisystemic extrapulmonary manifestations , such as electrolyte disorders , renal dysfunction , and liver dysfunction . among the electrolyte disorders , hypophosphatemia is noted as one of the common features and is used as part of the diagnostic criteria for legionella pneumonia . in general , phosphate homeostasis is mainly regulated by the endocrine system , specifically by parathyroid hormone ( pth ) , 1,25(oh)2 vitamin d , and fibroblast growth factor-23 ( fgf-23 ) . we report 2 cases of legionella pneumonia compli cated with hypophosphatemia and the evaluated mineral homeostatic regulators associated with phosphate control . a 54-year - old male visited the emergency department because of fatigue and fever a day before admission . the patient 's medical history revealed that he had started treatment for hypertension 3 years ago and that he had been prescribed valsartan ( 80 mg / day ) and amlodipine ( 5 mg / day ) . physical examination showed a bmi of 27.5 kg / m , blood pressure of 156/96 mm hg , pulse rate of 137 bpm , temperature of 40.1c , oxygen saturation of 95% ( room air ) , and crackles at the base of the right lung . ct was performed , and ground - glass opacities were detected in the right middle and lower lobes . considering these clinical findings together with a positive urinary test for legionella antigen ( binax , portland , maine , usa ) , a diagnosis of legionella pneumonia was confirmed . the patient had mild renal dysfunction and hypophosphatemia , while the other electrolytes were within the normal range . urinary n - acetyl - d - glucosaminidase ( u - nag ) and urinary 2-microglobulin ( u-2-mg ) levels were also elevated . after initiation of antibiotic therapy , serum c - reactive protein ( crp ) levels improved ( fig . serum phosphate and ratio of maximal tubular reabsorption of phosphorus / glomerular filtration rate ( tmp / gfr ) levels reached the normal range on the 5th day after admission . a 71-year - old male presented with fever , nausea , and fatigue 3 days before admission . physical examination showed a bmi of 21.7 kg / m , blood pressure of 140/90 mm hg , pulse rate of 102 bpm , temperature of 40.1c , oxygen saturation of 95% ( 2 liter / min , nasal cannula ) , and crackles in the left lung . a urinary test for legionella antigen was positive , and the diagnosis of legionella pneumonia was confirmed . serum creatinine levels were within the normal range ( 0.88 mg / dl ) , and estimated gfr was 65.6 ml / min/1.73 m. arterial blood gas measurement revealed hypoxemia and mild respiratory alkalosis . as for mineral homeostatic regulators , serum fgf-23 level was unmeasurably low , 1,25(oh)2 vitamin d was within the normal range ( 57.2 pg / ml , normal range : 20.060.0 ) , and intact pth ( i - pth ) was not elevated ( 30 pg / ml , normal range : 15.068.0 ) on admission . after administration of ciprofloxacin at 600 mg / day , the levels of serum crp , u - nag , and u-2-mg improved ( fig . renal tubular dysfunction , including glycosuria , proteinuria , panaminoaciduria , and phosphaturia , improved with recovery from pneumonia . delayed serum fgf-23 levels gradually increased with improvement in renal tubular dysfunction , serum phosphate , and tmp / gfr levels . a 54-year - old male visited the emergency department because of fatigue and fever a day before admission . the patient 's medical history revealed that he had started treatment for hypertension 3 years ago and that he had been prescribed valsartan ( 80 mg / day ) and amlodipine ( 5 mg / day ) . physical examination showed a bmi of 27.5 kg / m , blood pressure of 156/96 mm hg , pulse rate of 137 bpm , temperature of 40.1c , oxygen saturation of 95% ( room air ) , and crackles at the base of the right lung . ct was performed , and ground - glass opacities were detected in the right middle and lower lobes . considering these clinical findings together with a positive urinary test for legionella antigen ( binax , portland , maine , usa ) , a diagnosis of legionella pneumonia was confirmed . the patient had mild renal dysfunction and hypophosphatemia , while the other electrolytes were within the normal range . urinary n - acetyl - d - glucosaminidase ( u - nag ) and urinary 2-microglobulin ( u-2-mg ) levels were also elevated . after initiation of antibiotic therapy , serum c - reactive protein ( crp ) levels improved ( fig . serum phosphate and ratio of maximal tubular reabsorption of phosphorus / glomerular filtration rate ( tmp / gfr ) levels reached the normal range on the 5th day after admission . a 71-year - old male presented with fever , nausea , and fatigue 3 days before admission . physical examination showed a bmi of 21.7 kg / m , blood pressure of 140/90 mm hg , pulse rate of 102 bpm , temperature of 40.1c , oxygen saturation of 95% ( 2 liter / min , nasal cannula ) , and crackles in the left lung . a urinary test for legionella antigen was positive , and the diagnosis of legionella pneumonia was confirmed . serum creatinine levels were within the normal range ( 0.88 mg / dl ) , and estimated gfr was 65.6 ml / min/1.73 m. arterial blood gas measurement revealed hypoxemia and mild respiratory alkalosis . as for mineral homeostatic regulators , serum fgf-23 level was unmeasurably low , 1,25(oh)2 vitamin d was within the normal range ( 57.2 pg / ml , normal range : 20.060.0 ) , and intact pth ( i - pth ) was not elevated ( 30 pg / ml , normal range : 15.068.0 ) on admission . after administration of ciprofloxacin at 600 mg / day , the levels of serum crp , u - nag , and u-2-mg improved ( fig . 2 ) . renal tubular dysfunction , including glycosuria , proteinuria , panaminoaciduria , and phosphaturia , improved with recovery from pneumonia . delayed elevation of 1,25(oh)2 vitamin d levels was present on the 3rd day after admission . serum fgf-23 levels gradually increased with improvement in renal tubular dysfunction , serum phosphate , and tmp / gfr levels . hypophosphatemia is a common complication associated with legionella pneumonia , although the underlying mechanism is unclear . both showed increased renal phosphate excretion on admission , which rapidly resolved during recovery from legionella pneumonia . renal phosphate reabsorption takes place mostly in the proximal renal tubules . in general , the etiology of increased renal phosphate excretion includes 2 main causes : proximal renal tubular dysfunction , such as fanconi syndrome , and a disorder of the physiological mineral homeostatic regulators such as fgf-23 , pth , and 1,25(oh)2 vitamin d . the present cases demonstrated elevated u - nag and u-2-mg levels , proteinuria , glycosuria , and panaminoaciduria , all of which resolved rapidly with improvement of legionella pneumonia . these findings suggest that proximal renal tubular dysfunction may occur transiently in cases of legionella pneumonia . however , no report has measured mineral homeostatic regulators in legionella pneumonia . in the present case 2 , serum fgf-23 level was unmeasurably low on admission and gradually increased as serum phosphate levels normalized , whereas serum pth levels were not elevated during the whole period . these results suggest that both fgf-23 and pth were not responsible for hypophosphatemia in legionella pneumonia . serum 1,25(oh)2 vitamin d level was within the normal range on admission despite the presence of severe hypophosphatemia . three days after admission , delayed elevation of serum 1,25(oh)2 vitamin d level was observed with improvement of renal tubular dysfunction . hypophosphatemia has been postulated to accelerate the production of 1,25(oh)2 vitamin d through the activation of cytochrome p450 27b1 ( cyp27b1 ) in renal proximal tubules [ 6 , 7 ] . previous reports have mentioned that impaired activation of 1,25(oh)2 vitamin d is induced by proximal renal tubular dysfunction associated with tubulointerstitial nephritis or fanconi syndrome [ 8 , 9 ] . taking these facts into consideration , we speculated that there was a possibility that proximal renal tubular dysfunction caused the delayed elevation of 1,25(oh)2 vitamin d. it could be one of the additive reasons for hypophosphatemia in legionella pneumonia . interestingly , serum fgf-23 levels gradually increased with improvement in renal tubular function , serum phosphate , and tmp / gfr levels . although the regulator of fgf-23 is still not fully understood , the time course of serum fgf-23 levels gives us speculation that renal tubular function , renal phosphate excretion , and serum phosphate levels might contribute to the regulation of fgf-23 secretion . known causes of proximal renal tubular dysfunction include congenital diseases , adverse drug reactions , m - protein disorders , collagen diseases , and exposure to heavy metals . in the present cases , proximal renal tubular dysfunction could have been caused by legionella pneumonia itself because the findings of renal tubular dysfunction were resolved when legionella pneumonia improved , and the patients did not have any other causes . legionella pneumophila is a well - known facultative intracellular bacterium . to avoid interaction with host cell lysosomes and proliferative pathogens , legionella pneumophila requires components of many host cell organelles , such as endosomes , mitochondria , ribosomes , and endoplasmic reticulum . as for renal complications , tubulointerstitial nephritis and the presence of legionella pneumophila considering these features , we speculated that renal proximal tubules might be the most susceptible tissues because of the presence of mitochondria - rich lesions . as a limitation , we evaluated mineral homeostatic regulators in only 1 of the present cases . however , there were no previous reports that showed its regulators in legionella pneumonia , and thereby we considered that the present cases were worth reporting . in conclusion , our cases suggested that hypophosphatemia due to legionella pneumonia was caused not by fgf-23 and pth but by renal tubular dysfunction . Output:	we encountered 2 cases of hypophosphatemia due to legionella pneumonia . both cases showed increased urinary phosphate excretion and renal tubular dysfunction , which ameliorated with recovery from legionella pneumonia . serum fibroblast growth factor-23 level was suppressed , whereas serum 1,25(oh)2 vitamin d and parathyroid hormone levels were normal . delayed elevation of serum 1,25(oh)2 vitamin d levels was observed with improvement in renal tubular function . these findings suggested hypophosphatemia might be mediated by renal tubular dysfunction .
PubmedSumm118858	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: understanding the factors responsible for trp fluorescence changes is critical to interpretation of biologically relevant , solvent - phase protein structure . the basis for the observed thirty - fold variation in tryptophan ( trp ) fluorescence emission intensity ( quantum yield ) in proteins has been under study for the last 40 years . within the past 20 years , the role of charge transfer has gained increasing importance in explaining fluorescence changes in intensity , lifetime , and wavelength and is probably considered the primary factor in quantum yield reduction for trp in proteins . proton transfer from a terminal ammonium group to trp can reduce quantum yield , but in proteins , where amide groups predominate , quenching occurs by electron transfer from the ring to an amide . the protein environment of a single tryptophan can be very complex as many residues , charged or nonpolar , as well as backbone amides may be within a 4 radius of interaction with the fluorescent indole ring . in order to reduce the potential number of groups affecting quantum yield , we chose to examine the fluorescence characteristics of the lys - trp dipeptide in all possible charge states . as in previous studies of trp dipeptides , we employ quantum mechanical ( qm ) calculations and molecular dynamics ( md ) simulations to provide information on the dominant molecular conformations . we examine these in tandem with fluorescence lifetimes , steady - state fluorescence emission spectra , and quantum yield determinations for all lys - trp charged species . as before , we find that backbone - ring interactions for all lys - trp species are controlled by the dihedral angle , chi 1 , and that three angles predominate : 60 , 180 , and 300. digital switching between the chi 1 conformers is also observed . unlike past studies , however , terminal amine cation indole interactions are all but absent and so can not be used to explain spectroscopic features for the cationic species . the van der waals contacts for lys - trp cations are not qualitatively or quantitatively different from those observed for the zwitterion or anion species , and so these also can not account for the precipitous decrease in cationic quantum yield and shorter fluorescence lifetimes . in addition , the relative stability of the 60 , 180 , or 300 chi 1 rotamers is unlikely to be a factor because , unlike the previous trp - glu study , they do not display recognizably significant differences in their stability . these spectroscopic features remain inexplicable until the evidence of exoring negative charge on c and the possibility of alternate indole resonance structures and changes in aromaticity are considered . therefore , we examine qm - md - derived indole ring isosurfaces , which show the ground state -electron density at specific distances from the ring plane . this exercise reveals a trend in decreased ring charge density and delocalization ( i.e , loss of aromaticity ) with increased positive charge on the peptide backbone and lys residue , which is paralleled by decreased quantum yield and fluorescence lifetime . a dramatic decrease in the intensity is seen above the pka of the indole amine , which is also predicted by the notable alteration in isosurface charge distribution or aromaticity . in the absence of isosurface data for proteinaceous trps , observed extremely low quantum yield is explained with similar changes in aromaticity for tryptophans that are hydrogen bonded at the indole amine . this is expected to give rise to the nonaromatic -electron density distribution observed for the deprotonated indole tautomer . the association between ground state conformation and fluorescence of aromatic compounds , including indole derivatives , was first studied in 1970 by ib berlman . more recently , the optical and electronic properties of aryl - substituted benzobisoxazoles and pyrenes have been tuned via substituents that affect the -conjugated electrons . these substituents mainly affect the highest occupied molecular orbital ( homo , ground state ) and lowest unoccupied molecular orbital ( lumo , first excited fluorescent state ) , but it has been demonstrated that the homo can be tuned without significantly affecting the lumo . thus it is found that the ground state can tune fluorescence properties . these results further support our finding that the ground state isosurfaces of lys - trp dipetide species correlate with quantum yield and fluorescence lifetimes because for indole , the homo is the predominant ground state for the fluorescing transition dipole , la . in comparing the isosurfaces of the lys - trp dipeptide species , we find that the electron density distribution for the isosurfaces of the highly fluorescent zwitterion and 1 charged species resemble that for the calculated homo molecular orbital for indole , which is the dominant ground state orbital for the fluorescent transition dipole , la . this is the first time that changes in tryptophan quantum yield and lifetimes have been linked to changes in ring aromaticity . the fluorescence emission maximum for each lys - trp species is given in table 1 . these values are red - shifted relative to the emission maximum for aqueous trp at 350 nm . the quantum yield measurements require recording absorption spectra for the lys - trp dipeptides . the quantum yields for lys - trp charged species fall into two sets : a low quantum yield for ( lys - trp ) ( ph 1.5 , qy = 0.032 ) , ( lys - trp ) ( ph 5.3 , qy = 0.059 ) , and ( lys - trp ) with deprotonated indole amine ( ph 13.0 , qy = 0.014 ) , and a higher quantum yield , qy= 0.14 , identical to that of l - trp , for lys - trp zwitterion ( ph 9.3 ) and ( lys - trp ) ( ph 11.0 ) . protonation at the indole amine at ph 1.5 is not a consideration because trp quantum yield is already at a minimum at this ph while the indole minimum is at a ph < 1 . in a study of tyr mutants at positions 8 and 10 of a 12-mer -hairpin peptide , the quantum yield of the adjacent trp dropped to 0.02 at a ph above the tyr pka . this suggests formation of a tyro , indole amine hydrogen bond , where partial deprotonation of the indole amine results in a very low qy as for the lys - trp dipeptide at ph 13.0 ( above the pka of the indole amine ) . the first set of lifetimes , ( set 1 ) , found in the first column of table 2 , is derived from measurements made on the ti : sapphire - pumped laser system ( ca . 45 ps instrument response function , fwhm ) , while the second set ( set 2 ) derives from the photodiode system ( 1.47 ns instrument response function , fwhm ) . the fluorescence decay datum obtained on the ti : sapphire instrument for the lys - trp species at ph 1.5 is shown in figure s1 of the supporting information , while the data obtained from both instruments for the species at ph 11.0 are shown in figures s2 and s3 of the supporting information . fluorescence decay analyses found two or three lifetimes for each lys - trp species ( table 2 ) . a subnanosecond lifetime dominates the results for ( lys - trp ) ( ph 1.5 ) : 0.589 ns ( amplitude = 71% ) , set 1 . the average lifetime for ( lys - trp ) is 0.769 ( table 2 , italics ) . a reliable fit to lifetime decay data from the photodiode system could not be obtained . two lifetimes of equivalent amplitude comprise the set 1 results for ( lys - trp ) ( ph 5.3 , table 2 ) : 0.629 and 2.17 ns . set 2 is dominated by similar lifetimes with a different amplitude distribution : 0.538 ns ( a = 15% ) and 1.45 ns ( a = 79% ) . the average lifetimes for ( lys - trp ) in both data sets are 1.4 ns , noticeably longer than that for the ( lys - trp ) species . both sets of lifetimes for lys - trp zwitterion ( ph 9.3 ) are dominated by two ns lifetimes of magnitude 2 < < 4 but amplitudes vary . amplitude is nearly evenly split between lifetimes of 2.44 and 4.01 ns in set 1 , while a lifetime of 3.25 ns dominates set 2 ( a = 71% ) . the average lifetime in both data sets is 3 ns , which is significantly longer than that of the ( lys - trp ) species . the two lifetimes of set 1 for ( lys - trp ) ( ph 11.0 ) , 1.78 and 3.70 ns , are shorter than those for the lys - trp zwitterion in set 1 , but the average lifetime is the same ( 3 ns ) . set 2 lifetimes consist mainly of a dominant ( a = 72% ) lifetime of 2.72 ns and a longer lifetime of 7.89 ns ( a = 21% ) with an average lifetime of 4 ns . the lifetime measurement for the indole conjugate base of ( lys - trp ) ( ph 13.0 ) ( i.e. , the indole amine is deprotonated ) is dominated ( a = 98% ) by a 0.9 ns lifetime . gly - trp , and trp - glu dipeptide species , molecular dynamics simulations for the lys - trp dipeptide species show that the relative position of the backbone to the indole ring is defined by the chi 1 dihedral angle . 60 , 180 , and 300. the simulated time course of the chi 1 angle changes for four of the lys - trp species are given in figures s4s7 of the supporting information . as for other trp dipeptides , conformational switching between chi 1 angles can generally be described as digital . that is , the molecule resides at or near one of the characteristic chi 1 angles before switching instantaneously ( ca . 1 fs ) to another of the preferred chi 1 angles . italicized numbers are amplitude - weighted average lifetimes . the chi 1 = 300 conformation is generally the most disfavored for all lys - trp charged species while the chi 1 = 60 conformation is the most favored by all species except ( lys - trp ) . the lowest energy conformers for lys - trp dipeptide charged species are shown in figure 1 along with their probability , and the electrostatic potential ( in atomic units ) through the indole plane . indole ring interactions within 4 are included in table s1 of the supporting information , although the strength of these interactions is not included . generally , ring - backbone attractive interactions are balanced by an equal number of repulsive interactions . intramolecular backbone the atomic labeling used to describe these intramolecular interactions is given in figure 2 . electrostatic potential surfaces of the indole plane for all lowest energy lys - trp species . all conformers are arranged in order of increasing chi 1 angle from left to right : 60 , 180 , and 300. the probability , p , of each conformer is indicated . ( a c ) ( lys - trp ) , ( d f ) ( lys - trp ) , ( g i ) ( lys - trp ) , ( j l ) ( lys - trp ) . significant electrostatic interactions ( < 4 ) are given in table s1 of the supporting information . the electrostatic potential scale at the bottom of each conformer is in atomic units , with red indicating negative charge and blue , positive charge . the lysine residue is usually not found in the vicinity of the indole ring ( figure 1 ) except for the ( lys - trp ) chi 1 = 60 , ( lys - trp ) , and ( lys - trp ) chi 1 = 300 conformers . the general disposition of the lysine residue in the remaining conformers is one of an extended chain positioned far from the indole plane . in general , ring - backbone stabilizing interactions are balanced by destabilizing interactions at similar interatomic distances for most lys - trp conformers ( table s1 of the supporting information ) . these interactions support the idea that backbone - ring orientation is driven by steric hindrance rather than electrostatic interactions . such destabilizing interactions provide for the increased frequency of chi 1 angle switching between the three dominant angles and , therefore , the roughly equal probability of the major lys - trp conformers . interaction of the n - terminal amine cation with the indole ring , observed in trp - gly , gly - trp , and trp - glu charged species , is observed only in the ( lys - trp ) chi 1 = 60 conformer . lys - trp backbone conformations are stabilized by hydrogen bonds between backbone charged groups ( table s2 of the supporting information ) . for the sake of brevity , only the conformers with higher probability are discussed . for all ( lys - trp ) conformers ( table s1 of the supporting information ) , there are 19 favorable ring - backbone interactions within 4 . the chi 1 = 180 conformer ( p = 56% ) is stabilized by four interactions of the c - terminal carboxylic acid hydroxyl group with indoles c3 , c4 , c4-h , and c9 . the lower probability ( p = 24% ) chi 1 = 300 conformer is stabilized by peptide carbonyl and amine interactions with the ring . the peptide nh is electrostatically attracted to c2 and c3 , and the peptide carbonyl is positioned 2.83 from the indole c2 hydrogen . there are also 19 favorable ring - backbone interactions within 4 for all ( lys - trp ) conformers ( table s1 of the supporting information ) . only the chi 1 = 60 conformer ( p = 43% ) shows ring interaction with the terminal amine cation . the chi 1 = 180 ( p = 40% ) conformer only shows three terminal cooh ring interactions and one peptide carbonyl interaction . = 60 conformer ( p = 48% ) , interactions with the terminal coo are favored over those with the peptide carbonyl and amine . the 180 conformer ( p = 31% ) has four attractive interactions with the terminal coo . the chi 1 = 60 conformer ( p = 50% ) has numerous ring interactions with the peptide carbonyl and amine and the terminal carboxylate . the chi 1 = 180 conformer ( p = 39% ) has only a single ring interaction each with the terminal carboxylate and the peptide carbonyl . while a pattern for charged species backbone indole ring interactions is difficult to distinguish , we note that a terminal nh3amide o hydrogen bond is peculiar to conformers for the positively charged species ( table s2 of the supporting information ) . electron density isosurfaces ranging from 0.02 to 0.30 in increments of 0.01 were generated for the indole ring of trp in each of the conformers for five lys - trp species . isosurfaces where negative charge first appears over the indole ring are given in figure 3 for one low - energy chi 1 conformer for each dipeptide charged species . for all charged species , the isosurface shown represents the charge distribution for one or more of the remaining two conformers of that charged species . note the progressive shift of the zero charge point to the blue end of the scale as negative charge on the dipeptide increases . where isosurface charge distribution varied for a conformer , that isosurface is represented by an inset structural model . isosurfaces not illustrated are included in supporting information as slide files of isosurfaces up to an isosurface value of 0.15 . -electron density ( 0.00049 ) first appears at c4 c7 , along the n c2 bond and at c at the 0.08 isosurface for the chi 1 = 60 conformer of ( lys - trp ) ( figure 3a ) . the remaining ring carbons , c3 , c8 , and c9 , are positive at this isosurface value ( 0.195 ) . at isosurface value 0.11 , c7 and c are the most negative ( 0.0631 ) ; c3 , c8 , and c9 remain positive ( ca . 0.200 ) ; remaining ring atoms have close to zero charge . at an isosurface value of 0.15 , the c carries more negative charge ( 0.170 ) than any ring atom except nitrogen . isosurfaces for the chi 1 = 300 conformer of ( lys - trp ) share this charge distribution . -electron density first appears at isosurface 0.05 ( 0.00190 ) from c4c7 . at isosurface 0.08 , c4c7 and c at an isosurface value of 0.13 , c4 , c7 , and c are most negative ( 0.112 ) ; c3 , c8 , and c9 remain positive . the pattern of -electron density for the chi 1 = 180 conformer of ( lys - trp ) differs ( figure 3a , inset ) . c4c7 and c2 bond first appear negatively charged ( 0.000157 ) at isosurface 0.06 , but c is positive , as are c8 and c9 ( ca . negative charge ( 0.0623 ) can be found at c4 c7 and at the n for all ( lys - trp ) conformers , the ring -electron density is not uniform over the indole ring ; the aromaticity would be diminished . for all ( lys - trp ) conformers , a weak -electron density ( 0.076 to 0.03 ) appears at an isosurface value of 0.02 ( figure 3b ) , further from the indole ring plane than in ( lys - trp ) . c8 and c9 remain positive ( < 0.1 ) . for the chi 1 = 60 conformer of ( lys - trp ) ( figure 3b , inset ) at isosurface 0.02 , the weak negative charge extends to c , while for the chi 1 = 180 and chi 1 = 300 , it does not ( figure 3b ) . for this cation , the ring -electron density lacks uniformity over the entire indole molecule , and the aromaticity is still diminished over most of the isosurfaces studied for this charge species . for all ( lys - trp ) conformers , -electron density ( ca . 0.15 0.10 ) appears at c4c7 at an isosurface value of 0.02 ( figure 3c ) . c8 , c9 , and c are weakly negative in the 60 and 180 conformers only . c2c3 portion of the pyrrole ring also has relatively high -electron density in the 60 and 180 conformers ( figure 3c ) . as the isosurface value increases ( where the distance is closer to the ring plane ) , -electron density concentrates at c4c7 and n c2c3 , while c8 and c9 become less negative . the -electron density distribution for the 300 conformer ( figure 3c , inset ) deviates from the above pattern in that n and c3 carry a charge of ca . 0.1 , but c2 is only slightly negative . as the isosurface value increases , c3 carries the greatest ring charge for the 300 conformer . all ring atoms of all ( lys - trp ) conformers carry a -electron density of ca . for both the ( lys - trp ) and ( lys - trp ) species , the -electron density is continuous even at the 0.020 isosurface , conferring aromaticity to these species . deprotonation of the indole amine is predicted to result in bond migration ( tautomerization ) from c2 - --c3 to n --- c2 . while the pka of indole in dimethyl sulfoxide is 21 , and substitution of c3 with n reduces pka to only 16.4 , osysko and muino similarly found that the quantum yield of aqueous trp , trp - asp , and trp - arg dipeptides dropped precipitously above ph 11 . they attributed the quantum yield decrease to deprotonation of the indole amine , as crossing of the potential energy surface for the nonradiative rydberg state , a ( * ) , with those of the fluorescent la( * ) and ground states occurs as a function of the indole n --- h distance . the 0.02 isosurface for the ( lys - trp)/ind n conj base ( figure 3e ) indeed shows 0.17 to 0.1 -electron density around the benzyl ring and at c2 . the pyrrole n has the highest negative charge ( 0.2 ) , while c3 is only weakly negative ( less than 0.06 ) . a different pattern of -electron density on the indole ring results for this species . the tautomer structure for indole with deprotonated pyrrole is given in the inset of figure 3e . nmr spectroscopy of lys - trp at ph 1.5 and 12.5 was carried out to confirm the changes in aromaticity observed in isosurfaces . chemical shifts for indole c2 , c4 , and c7 hydrogens were 0.5 ppm , which is within the standard error on peak positions in proteins . therefore , nmr is insensitive to the diminished aromaticity found in the isosurface studies , unlike fluorescence quantum yield . the harmonic oscillator measure of aromaticity ( homa ) and nucleus - independent chemical shifts method ( nics ) were not appropriate for our molecules and did not yield values that tracked with changes in quantum yield or fluorescence lifetime . the homa measure of aromaticity ( 41 ) is better - suited to predicting aromaticity in different extended ring systems where there are substantial changes in bond length and the number of rings changes . for example , for perylene , the center ring homa index is 0.140 , whereas the highest index for an outer ring is 0.842 . the difference between our dipeptides is in the charge on the backbone and the change in orientation of the backbone with respect to the indole ring . the variation in homa aromaticity index for the indoles in the lystrp dipeptides in different charge states is small : 0.8290.845 , and does not track with the quantum yield or fluorescence lifetimes . this is an indirect effect of the electron density and configuration within the molecule . the absorption and fluorescence , however , relate to the state of the electronic energy levels and are more directly affected by the electron density in the indole ring . the ncsi information tells very little , if anything at all , about the aromaticity differences . it does show a very slight increase of aromaticity for the ( lys - trp ) over the ( lys - trp ) when not in the plane of the nuclei of the indole ring , but a slight decrease of aromaticity when in or very close to the atoms of the indole ring . the calculated differences between the two species might be small enough to be indistinguishable experimentally . charge density isosurfaces for the indole of each lys - trp charged dipeptide . the color - coded electrostatic potential scale , with zero potential marker , is given above each figure . the inset figures are models for the isosurface of conformers not represented by the color images . solid contour lines represent ring position of high electron density ( 10 ) while dashed lines represent ring position of weak election density ( less than 10 ) . where no contour line is present , the isosurface show zero or positive charge . ( a ) ( lys - trp ) , chi 1 = 60 , 0.080 isosurface ; also represents the 0.050 isosurface of the 300 conformer . inset : chi 1 = 180 , 0.060 isosurface ( b ) ( lys - trp ) , chi 1 = 180 and 300 , 0.020 isosurface . ( c ) ( lys - trp ) , chi 1 = 60 and 180 , 0.020 isosurface . ( d ) ( lys - trp ) chi 1 = 60 , 0.020 isosurface ; represents 0.020 isosurface of all anionic conformers . ( e ) ( lys - trp)/ind n conj base , chi 1 = 60 , 0.02 isosurface . ( f ) highest occupied molecular orbital ( homo ) for indole in vacuum calculated via an ab initio method ( mp2/631 g * ) image adapted from ref ( 44 ) . this is the major ground state orbital for the la transition , the primary fluorescing transition in indole . a common pattern is found for lys - trp species quantum yields and fluorescence lifetimes . while the number of lifetimes for each data set ( table 2 ) and species varies , lifetimes with the highest amplitude have a match across the two sets for each species when available , and weighted average lifetimes are similar for both data sets . the dominant lifetime for ( lys - trp ) ( ph 1.5 , table 2 ) is 0.589 ( a = 71% ) . a 10 ns lifetime is also found for ( lys - trp ) ( ph 5.3 , table 2 ) in both data sets , but the amplitude of this component has diminished ( a = 48% and 15% ) . instead , 10 ns lifetimes dominate fluorescence decays . with the loss of a proton on the n - terminal amine , lifetimes are dominated by two 10 ns values ( table 2 , phs 9.3 and 11.0 ) . when the indole amine is deprotonated ( table 2 , ph 13.0 ) , a 10 ns lifetime once again dominates ( a = 98% ) , and there is a minor ( a = 2% ) 9 ns component . weighted average lifetimes result in a 0.77 ns lifetime for ( lys - trp ) , 1.0 for ( lys - trp)/ind n conj base , and a 1.4 ns lifetime for ( lys - trp ) . weighted average lifetimes for ( lys - trp ) and ( lys - trp ) are all in the 34 ns range for both data sets ( table 2 ) . weighted average lifetime ( ns , sets 1 and 2 , table 2 ) plotted as a function of quantum yield ( table 1 ) for lys - trp species at ph 1.513.0 . linear fit plotted with y intercept at ( x , y ) = ( 0,0 ) , r = 0.894 . cations , ( lys - trp ) and ( lys - trp ) , have low quantum yields of 0.032 and 0.059 ( table 1 ) . the quantum yield for the ( lys - trp)/ind n conj base is the lowest obtained , 0.014 . the lys - trp zwitterion and anion , however , both have quantum yields of 0.14 , which is the same value obtained for trp at ph 7.4 . plotting the weighted average lifetime as a function of quantum yield reveals a linear relationship for the lys - trp species ( figure 4 ) . such a clear relationship between these fluorescence parameters does not exist for single tryptophan proteins . this is likely due to the superposition of effects caused by numerous residues for protein tryptophans . in earlier studies of the trp - gly , gly - trp , and trp - glu species , a terminal amine cation was found in close proximity to the indole ring for several conformers of charged species , which would facilitate proton transfer . for the lys - trp species studies here , a terminal amine cation in close proximity ( 3.7 , table s1 of the supporting information ) to an indole ring is found only for the ( lys - trp ) chi 1 = 60 conformer . favorable van der waals ring contacts with the peptide amide and/or terminal carbonyl groups provide for possible electron transfer for all four lys - trp species below ph 13 . indeed , these van der waals contacts are most likely a major quenching route for all species , as even the relatively strong fluorescing zwitterion and anion have a diminished quantum yield of 0.14 relative to the high value of 0.34 observed for aqueous 3-methylindole . theoretical and spectroscopic studies of n - acetyl tryptophan amide ( nata ) and its methyl amide ( natma ) have revealed an le excited state along a peptide backbone hydrogen bond , which acts as an excitation conduit from the fluorescent la state to charge transfer ( ct ) deexcitation . the reduced and asymmetric -electron density for the indole in these lys - trp cationic species may constitute a telltale for such a ct state . quantum mechanical isosurface charge distribution for lys - trp peptides shows changes in ring aromaticity with molecular charge and pkr . one factor that has not been considered is the effect of molecular charge on distribution of ring -electron density . the isosurface charge distribution on the indole ring for ( lys - trp ) conformers reveals a -electron density that is diminished and weak , extending above the ring plane only to isosurface 0.050.08 ( i.e. , near the ring plane ) ( figure 3a ) . furthermore , charge density does not encircle the ring , and charge density is found off the ring on c , suggesting that a resonance structure with off - ring conjugation is favored . this results in greatly diminished aromaticity for the ( lys - trp ) species , which increases the ground state energy of the indole ring , placing it closer to the le origin . short - lived deexcitation pathways , such as the le to ct transition , are favored over the nanosecond fluorescence emission route . a low quantum yield ( 0.032 ) and a predominant subnanosecond lifetime ( table 2 ) is characteristic of nonaromatic compounds and are observed here for the ( lys - trp ) species . a small increase in ring charge density is found for ( lys - trp ) conformers in that weak charge is extended out to the 0.02 isosurface ( figure 3b ) , but the -electron density is not continuous about the ring here either . charge density along the c3c bond is observed for the 60 conformer , suggesting that exoring conjugation also contributes to the -electron density distribution . quantum yield is also low for ( lys - trp ) ( 0.059 ) , but lifetimes have increased with an average lifetime of 1.4 ns . a smaller positive charge on the dipeptide allows for an increased stabilization of the excited state and , therefore , a small increase in fluorescence lifetime . the lys - trp zwitterion 0.02 isosurface charge density is stronger still and continuous about the ring ( figure 3c ) . exoring charge density does not appear to be a part of the -electron distribution as the isosurface shows c to be positively charged . the quantum yield , 0.14 , is identical to that for trp in water . the -electron density distribution on the indole ring for the ( lys - trp ) conformers is strong and relatively uniform at the 0.02 isosurface ( figure 3d ) . aromaticity prevails , and the quantum yield is the same as for aqueous trp . negative charge on the peptide should stabilize the excited state where electrons are at a further distance from the indole plane and , therefore , favor the long - lived fluorescence emission process . deprotonation of the indole amine at ph 13.0 again disrupts the ring electron distribution ( figure 3e ) . there is little electron density at c3 and high electron density at the pyrrole nitrogen . the result is that quantum yield drops to 0.014 and the average lifetime is shortened to 1.0 ns . positive charge on c3 and the pyrrole ring is consistent with the dissociative state , * , which is predicted to cross the lb energy function just above the indole nh stretch vibration . our finding of loss of aromaticity for lys - trp cationic and deprotonated indole amine species provides a plausible explanation for the drop in quantum yield from 0.14 , observed for aqueous trp , to the minima of 0.01 observed in proteins . for the cationic species , backbone and lys residue positive charge can shift fluid ring -electron density toward the exoring c , as shown by the isosurfaces ( figure 3 , panels a and b ) . the ground state isosurfaces for the cationic lys - trp species ( figure 3 , panels a and b ) are lacking in -electron density at the c2 or c3 ring atoms characteristic of the fluorescent la ground state , the homo ( figure 3f ) . concomitantly , these same positive charges destabilize the electronic excited state , disfavoring the longer , nanosecond process of fluorescence emission . for the deprotonated indole amine species , the pyrrole c2 - --c3 double bond is shifted to n --- c2 and electron density is concentrated at the pyrrole nitrogen , a tautomer is favored ( figure 3e , inset ) . the corresponding isosurface ( figure 3e ) shows a very distorted ring -electron distribution , which is also very different from the fluorescent la ground state . loss of aromaticity favors a nonradiative process of deexcitation and a lower quantum yield , as found in the fluorescence spectra . this line of reasoning can be applied to the pka - dependent quantum yield results for mutants of a dodecamer -hairpin peptide , where residues flanking either face of a single tryptophan were mutated . plots of fluorescence yields follow the pka for the trp - flanking residue and the associated molecular charge . if the flanking residue is asp ( pkr = 3.65 ) , glu ( pkr = 4.25 ) , cys ( pkr = 8.18 ) , or his ( pkr = 6.00 ) , quantum yield is higher when the residue is in the anionic state and lower when the residue is protonated . this is readily explained by the diminished indole aromaticity found in the presence of positive charge as found here for lys - trp cations . when the flanking residue is tyr , the quantum yield for the -hairpin peptide follows a different rule with respect to the residue pkr , as discussed below . the strength of a concept rests in how well it explains the observed phenomena . as hydrogen bonding at the indole amine favors trp tautomerization ( figure 3e , inset ) , and the c3 tautomer has been shown to be of lowest energy , it is reasonable to expect that indole aromaticity and , therefore , quantum yield , would be affected , as observed here for lys - trp at ph 13 . this scenario has , in fact , been documented in studies of trp fluorescence in proteins . the ph - dependent fluorescence yields for trp in the -hairpin phe10tyr and ala8tyr mutants follow tyr pkr = 10.07 . examination of the nmr structure for the phe10tyr mutant provided therewithin shows that tyro --- trp pyrrole nh hydrogen bonding is possible . hydrogen bonding at the indole amine favors an indole tautomer - like structure and , therefore , a low quantum yield is expected and observed for the -hairpin mutant . in a study of the ph - dependence of fluorescence for the w126y / w158y / q105h single trp mutant of t4 lysozyme , average lifetime falls from 3 to 2 ns and fluorescence yield decrease 3-fold as ph rises above his pka . this result is in disagreement with the low trp quantum yields that have been associated with protonated his . as his replaces the wild - type gln105 in mutant t4 lysozyme , which crystal structure shows is hydrogen bonded to the trp138 indole amine , similar hydrogen bonding by the his anion was indicated . once again , a trp tautomer would be favored , leading to the observed lower fluorescence . the evidence supports a loss of aromaticity and a tautomer structure for the t4 lysozyme mutant trp138 above his pkr as observed here for lys - trp at ph 13.0 . finally , we examine the low quantum yield obtained for members of the homeodomain element from the family of homeotic proteins . the single trp human homeodomain , pbx-1 , with an extremely low quantum yield , contains a trp25 pyrrole nh - glu39 oe hydrogen bond of length 2.37 , as revealed by nmr.drosophila homeodomain antennapedia c39s mutant , which contains two trps , shows very low fluorescence emission with an average folded lifetime of 1.30 ns and a 4-fold increase in fluorescence emission upon unfolding . the nmr structure for this homeodomain shows a thr13 residue o - trp48 pyrrole nh hydrogen bond distance of 1.97 ( pdb 1hom ) . other drosophila homeodomains , ubx and eng , also exhibit very low fluorescence yield ; however , nmr or crystal structures free of the structure - altering dna adduct are not available , and so hydrogen bonding at the indole amine can not be checked . the concurrence of these results supports the concept of indole ring -electron density redistribution via hydrogen bonding at the indole amine and a drastic reduction in trp quantum yield as a result of loss of aromaticity that this electron density change causes . the lys - trp dipeptide was studied both spectroscopically and in silico in ph - induced charge states ranging from 2 to 1 and deprotonated at the indole amine . quantum yields for the lys - trp dipeptide species followed a linear relationship with fluorescence lifetime averages . as for trp - gly , gly - trp , and trp - glu dipeptides , the chi 1 dihedral angle is found to control the relative disposition of the backbone to the indole ring . simulations for lys - trp cations did not reveal a predilection for the terminal amine cation to interact with the indole ring . the absence of backbone and lys residue interaction with the indole ring in all charge states necessitates some explanation for the quantum yield and fluorescent lifetime decreases observed when lys - trp is in the cationic state or when the indole amine is deprotonated . a feasible explanation is provided by the quantum mechanically derived isosurfaces of the indole ring , which reveal molecular charge- and pkr - associated changes in -electron density that are tantamount to changes in ring aromaticity . it is noteworthy that the isosurface charge distributions for the higher quantum yield lys - trp zwitterion and anion most closely matches that of the calculated indole homo , which is the main ground state for the fluorescing la transition dipole moment . thus it is not necessary to calculate individual molecular orbital charge distribution as the isosurface represents the sum charge distribution , which can be compared to the ground state of the fluorescing la transition dipole moment . at ph 13 , where the indole amine is deprotonated , a tautomer is favored that concentrates -electron density at the nitrogen , and consequently the quantum yield is extremely low ( 0.014 ) . the ground state does not resemble that for the la transition dipole . in the absence of isosurfaces for proteinaceous trps , verification of a correlation between extremely low trp quantum yield and loss or aromaticity is found in extremely low fluorescing trp - containing proteins where hydrogen bonding at the indole amine can be demonstrated . the expected indole -electron charge distribution is like that observed here for lys - trp with deprotonated indole amine . it is noteworthy that these changes in aromatic character are not found using ordinary proton nmr . the electron density has a direct effect on the energy states that govern fluorescence phenomena , whereas the effect of aromaticity on the deshielding of neighboring protons is an indirect effect . here we see that fluorescence spectroscopy can be a more sensitive probe of the aromatic character of the indole ring electron density distribution . the ph was adjusted to 1.5 for ( lys - trp ) ( fully protonated ) , 5.5 for ( lys - trp ) ( additionally , terminal acid deprotonated ) , 9.5 for ( lys - trp ) ( terminal amine deprotonated ) , 11.5 for ( lys - trp ) ( lysine deprotonated ) , and 13.0 for ( lys - trp ) , indole conjugate base ( indole amine deprotonated ) . l - tryptophan was purchased from acros organics ( thermo - fisher scientific , nj ) , and 2-aminopyridine was purchased from alfa aesar ( ward hill , ma ) . background corrected absorption spectra were recorded on a cary 100 bio uv vis spectrophotometer ( varian instruments , walnut creek , ca ) with a 2 nm slit width , 1 cm path length , and 1 nm interval . fluorescence emission spectra for quantum yield determinations were recorded on a fluorolog 3 model fl-1000 ( horiba jobin yvon , edison , nj ) fluorometer using an excitation wavelength of 280 nm and a 1 nm interval . the integration time was set to 0.1 s. the slit width matched that of absorption spectrophotometer ( 2 nm ) . aqueous l - trp ( qy = 0.14 ) and 2-aminopyridine in 0.1 m sulfuric acid ( qy = 0.60 ) were used as quantum yield standards . lys - trp quantum yields were determined by the method given in ref ( 59 ) . briefly , the quantum yield of the two quantum yield standards are first determined via reference against each other to ensure confidence in quantum yields measured for the unknown . the integrated fluorescence intensity of each fluorophore is determined from emission spectra at several fluorophore concentrations , all less than 0.01 mm , to avoid the inner filter effect . the integrated intensity is plotted as a function of the measured absorbance at each concentration . a linear fit is calculated , ensuring that the fit line runs through the origin . the slope of the fit is the gradient , g , used in calculation of the quantum yield , qy : where the subscript , st , signifies the quantities for the quantum yield standard , and x are the quantities for the fluorophore of unknown quantum yield . is the refractive index for each solution : = 1.333 for water and = 1.334 for 0.1 m sulfuric acid . fluorescence lifetime measurement of the lys - trp dipeptide species , ph 1.511.0 , was carried out on two different instruments : a commercial instrument that employs a laser diode excitation source with a broad ( 1.47 ns ) instrument response function ( horiba jobin yvon , edison , nj ) , and a ti : sapphire - pumped , lab - built laser system at the nih - sponsored ultrafast optical processes laboratory ( university of pennsylvania , philadelphia , pa ) . lifetimes for the ph 13.0 species were measured on the laser diode system only . the ti : sapphire - based instrument uses the time - correlated single photon counting method . it provides 300 mw of approximately 800 nm with a repetition rate of 85 mhz . a lab - build beta barium borate - based , third harmonic generator yields the necessary 280 nm excitation pulses . ps fwhm ) was collected from the scattered light off a thin wire , which is necessary for proper deconvolution . emission at 340 nm was monitored in a magic angle geometry through a subtractive double monochromator with a microchannel plate - photomultiplier tube ( model r2809u , hamamatsu photonics , bridgewater , nj ) connected to a time - correlated single photon counting computer board ( model spc-630 , becker and hickl , berlin , germany ) . excitation was achieved at 280 nm , while emission was monitored at 340 nm in both set of lifetime measurements . the lifetime measurements were duplicated with an instrument of narrower response function ( i.e. , the ti : sapphire system ) . the lifetimes for decays collected on the diode instrument were determined by iterative convolution using the vendor - provided decay analysis , das6 . the lifetime decay data acquired on the ti - sapphire - pumped system were analyzed with the fitting program , fluofit ( picoquant , photonics north america , west springfield , ma ) . nmr spectra were obtained on a 200 mhz varian nmr ( agilent technologies , ca ) , using mestre - c v. 2.1.0 ( mestrelab research , escondido , ca ) for data processing and analysis . as mentioned , the b3lyp density functional theory method and 631++g(df , p ) basis set were utilized . the polarizable continuum method with implicit ground - state qm calculations for the favored chi 1 angles and lowest energy conformation , revealed by molecular dynamics , were performed . atomic charges were checked against the nbo ( natural bond orbital ) results and found to be consistent . the main goal of the calculations was to determine the electrostatic potential distribution in the dipeptide , as this gives insight into intramolecular interactions . the molekel 5.4.0.8 was used for visualization of the peptide species and their isosurfaces . isosurface values are not directly proportional to the actual distances from the nuclei , but the relationship between these isosurfaces and the distance from the indole ring can be estimated with the formula of d = y0 + ae , where d is the distance in , y0 = 0.370 , a = 1.105 , t = 0.07228 , and i is the isosurface value . simulations were carried out using gromacs 4.5.3 for all dipeptide species except the indole conjugate base . a cubic box of dimension 1 nm beyond the dipeptide boundary with 1000 water molecules was utilized . periodic boundary conditions were applied in three dimensions . 0.5 fs time steps for a total of 2030 ns were simulated , thus ensuring that all of the chi 1 dihedral angle space was sampled . Output:	several nonradiative processes compete with tryptophan fluorescence emission . the difficulty in spectral interpretation lies in associating specific molecular environmental features with these processes and thereby utilizing the fluorescence spectral data to identify the local environment of tryptophan . here , spectroscopic and molecular modeling study of lys - trp dipeptide charged species shows that backbone - ring interactions are undistinguished . instead , quantum mechanical ground state isosurfaces reveal variations in indole electron distribution and density that parallel charge ( as a function of pk1 , pk2 , and pkr ) on the backbone and residues . a pattern of aromaticity - associated quantum yield and fluorescence lifetime changes emerges . where quantum yield is high , isosurfaces have a charge distribution similar to the highest occupied molecular orbital ( homo ) of indole , which is the dominant fluorescent ground state of the 1la transition dipole moment . where quantum yield is low , isosurface charge distribution over the ring is uneven , diminished , and even found off ring . at ph 13 , the indole amine is deprotonated , and lys - trp quantum yield is extremely low due to tautomer structure that concentrates charge on the indole amine ; the isosurface charge distribution bears scant resemblance to the indole homo . such greatly diminished fluorescence has been observed for proteins where the indole nitrogen is hydrogen bonded , lending credence to the association of aromaticity changes with diminished quantum yield in proteins as well . thus tryptophan ground state isosurfaces are an indicator of indole aromaticity , signaling the partition of excitation energy between radiative and nonradiative processes .
PubmedSumm118859	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: " doctors are men who prescribe medicines of which they know little , to cure diseases of which they know less , in human beings of whom they know nothing " francois - marie arouet voltaire some nonphysicians may argue that little has changed since the 18th century . however , the advent of the clinical trial and multicentre studies may have helped to shed some light on practice . to this end the results of the soap ( sepsis occurrence in acutely ill patients ) study , published recently in critical care medicine , will cause a stir . that prospective study of 3147 patients took place in early may 2002 and joins the ranks of other such epidemiological work on the subject . the study was endorsed by the european society of intensive care medicine , and 24 european countries were involved , encompassing almost 200 intensive care units ( icus ) . patients were followed for up to 60 days , or until discharge or death if this occurred before 60 days . the volume of data collected is impressive , and further insight into outcomes from sepsis , as defined by the classical consensus conference criteria , can be gleaned . the incidence of sepsis approached 40% ( 37.4% ) , with the lung being the commonest site of infection . unsurprisingly , staphylococcus aureus was the most frequent organism , but rather worryingly 14% of isolates were methicillin resistant . there was a marked difference in the frequency of sepsis between countries , and higher frequencies of sepsis were mirrored by higher icu mortality rates . it is difficult to correlate this finding with any one factor but it may well reflect regional differences in icu resources as well as variations in case - mix and thresholds for icu admission . patients with sepsis had a longer length of stay both in the icu and in hospital , and they had more severe organ dysfunction and higher mortality rates . age , cancer , medical admission and septic shock were all associated with a worse outcome . also , an observed increase in patient mortality was associated with the degree of organ dysfunction , but interestingly there was little difference between the sepsis and nonsepsis groups in this regard , cementing the view that organ dysfunction is a bad thing whether sepsis is present or not . the soap study is interesting and a triumph in organizational terms , but its findings also contain one extremely important point that may provide a focus for several more studies . cumulative fluid balance within the first 72 hours of onset of sepsis was an independent predictor of outcome in the sepsis group . although multivariate analysis has attracted many criticisms , including its inability to account for unmeasured differences , this is still an intriguing finding , especially when it is viewed in tandem with findings reported by rivers and coworkers . perhaps this indicates that early , appropriate recognition of critical illness , and treatment of it , should be our aim and with this may come improved outcomes . one aim in treatment that has been embraced with great vigour is that of intensive insulin therapy and tight glycaemic control in the critically ill . this followed the landmark study by van den berghe and colleagues in 2001 , who demonstrated an impressive mortality benefit in surgical intensive care patients , such that previously ignored elevations in blood glucose have now become high priority therapeutic targets . that study and the wholesale implementation of intensive insulin therapy based on its findings have not been without their critics , given that the original work represented data from a single centre that was biased toward cardiac surgery with a relatively low severity of illness . few data are currently available regarding treatment of the more severely ill . however , the impact on clinical practice is unquestionable . recently published guidelines of the surviving sepsis campaign recommend intensive insulin therapy despite a lack of overwhelming evidence . it was hoped that the latest study from belgium would yield answers to some of these questions . van den berghe and colleagues enrolled 1200 patients over a 3-year period from 2002 on an intention - to - treat basis . all were patients on a medical icu who had a predicted length of stay of at least 3 days on the unit . patients were randomly assigned either to intensive insulin therapy ( insulin infusions to keep blood glucose between 4.4 and 6.1 mmol / l [ 80110 mg / dl ] ) or to standard therapy ( insulin to be administered if blood glucose exceeded 12 mmol / l [ 215 mg / dl ] and eased when levels fell below 10 overall , there was no significant difference in survival at 28 and 90 days for each patient group . more strikingly , there appeared to be a worse outcome in the intensive therapy group who were discharged to the general wards fewer than 3 days from admission to icu . however , in keeping with their previous work , the investigators found that patients who were on the icu for longer than 3 days exhibited an apparent morbidity and survival benefit , which was significant following intensive insulin therapy . this included reductions in days to wean from intermittent positive pressure ventilation , incidence of renal impairment ( but not incidence of dialysis ) and incidence of hyperbilirubinaemia . the investigators suggested that , for the protective effect of strict normoglycaemia to be realized , the therapy must be established for longer than the first few days of the illness , although they proposed no reason for the observed increase in mortality in the group treated for fewer than 3 days . what is clear is that hypoglycaemia was far more frequently observed in the intensive treatment than in the conservative group , and this was demonstrated to be an independent predictor of death . leading on from this , egi and colleagues reported on a study designed to assess the risks and benefits of intensive insulin therapy in postoperative icu patients . they selected a cohort of patients with clinical features similar to those of the cohort described by van den berghe and coworkers . for the 783 patients studied , all information on glucose control was retrieved , although none of the units employed specific protocols for insulin therapy . there overall findings suggested that 102 patients would have to be treated with intensive insulin treatment to prevent one death . they also calculated that treatment of 13 patients would lead to one episode of harm , in this instance severe hypoglycaemia ( defined as < 2.2 mmol / l ) . however , these results did vary widely depending on the clinical setting and case - mix . clearly , comparing the ultimate end - point with transient hypoglycaemia is far from ideal , but the study does alert us to the fact that application of intensive insulin therapy may not , as suggested previously , be universally applicable and is not without risk . this latter point was addressed by vriesendorp and coworkers . since employing more intensive insulin treatment regimens , those investigators have noticed an increase in hypoglycaemic events , similar to those reported by van den berghe and colleagues . they therefore set out to identify the factors that may make this such a common scenario within their patient population . over a 2-year period they examined all patients who had at least one episode of hypoglycaemia during the icu stay . vriesendorp and coworkers examined several parameters and found that diabetes , sepsis , need for inotropic support , use of bicarbonate - buffered replacement fluid during haemofiltration and decreased nutrition without insulin adjustment were independently associated with hypoglycaemia . so where do these studies leave us ? certainly , the days of ignoring high blood sugars on the basis of an ' adaptive response ' are gone . however , the dictatorial constraints of the van den bergh protocol may not be applicable to those of us who work in a predominantly medical icu . perhaps the way forward may well be a slightly more relaxed approach , certainly during the first 72 hours of admission , similar to the proposal by finney and colleagues in 2003 who speculated that a blood glucose level below 8.0 mmol / l should be the preferred treatment aim . assuming that we have identified our patient with sepsis and of course treated the blood glucose appropriately , what then ? when we are dispensing our polypharmacy , we should perhaps consider continuing the patient 's statin therapy . some studies have implied that statins may have diverse effects other than just lowering lipids . hackam and colleagues , in the lancet , reported that statin therapy in patients with cardiovascular disease may have additional benefits in preventing sepsis . in their observational study conducted in 141,487 patients in canada , they found reduced rates of sepsis , severe sepsis and fatal sepsis . this protective association was observed in all groups including those deemed to be at higher risk , such as patients with diabetes and renal failure . although not icu based , this is an interesting study and well worth a look . Output:	the eagerly awaited soap ( sepsis occurrence in acutely ill patients ) study is published and its observational data provide much of interest , not least in generating further hypotheses on improving treatment in this challenging group . glycaemic control in the critically ill is once more the focus of attention , and we discuss three studies in this area . not least among these reports is that from the van den bergh group , who provide further data on their intensive insulin protocol in a more heterogeneous group , namely medical intensive care unit patients . finally , we discuss another good reason to take statins .
PubmedSumm118860	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: eosinophilic esophagitis ( ee ) is a disease entity that has been diagnosed with increasing frequency . the first reported case of ee was in 1977 in an adult patient with food allergies , gastroesophageal reflux disease ( gerd ) symptoms , and esophageal eosinophilia . the definitive link between food allergies and ee was shown by dr kelly and colleagues in 1995 , when they described 10 patients with isolated esophageal eosinophilia unresponsive to acid blockade who improved with an elemental formula . their findings introduced the role of food allergy in ee . since the mid - nineties , there has been a dramatic rise in the number of patients diagnosed with ee . ee has now been reported in every continent except for africa , including every state in the united states and most of western europe . several reports have suggested that the prevalence of ee has increased in both pediatric and adult patients by 18- to 35-fold in the past 20 years [ 3 - 6 ] . it is important to note that there are no current approved medications for the treatment of ee , however , the use of the patients typically swallow inhaled corticosteroids used for asthma in moderate to high doses ( given without use of spacer and avoiding foods / liquids for 30 minutes ) . the goal of this therapy is to deposit steroids in the esophagus leading to apoptosis of the eosinophils and reduction of symptoms . konikoff et al . completed a randomized double - blind placebo - controlled trial of 36 pediatric patients with ee who either refused or failed dietary modification . they reported improved control of symptoms and less eosinophils per high power field ( eosinophils / hpf ) in biopsy in 50% of the patients . the success rate was 50% compared to an 80 - 90% success rate in the open - label trials with fluticasone or budesonide . cromolyn , montelukast ( a leukotriene receptor antagonist ) , and omalizumab ( an anti - ige antibody ) , did not show any histological improvement in open - label clinical trials . at this point , these drugs can not be recommended for ee . a recent open label trial of mepolizumab ( an anti - interleukin ( il)-5 antibody ) showed a significant improvement in four patients , with biopsy improving from 150 to 40 eosinophils / hpf ; however , this was still well above the normal level of 0 eosinophils / hpf . a second approach is to treat the cause of ee by eliminating the appropriate food . an elemental diet has been successful in both pediatric and adult patients , with success rates surpassing 95% . however , due to the poor palatability of these formulas , it is difficult for patients to remain on them . a more directed approach to eliminating the particular food antigen is possible ; two possible ways to remove the food antigen include removing the most common food allergens or removing the allergens based on allergy testing . the first method has been primarily studied by kagalwalla et al . in pediatric patients and by gonsalves in adults ( n gonsalves , personal communication ) . they found that a six - food elimination diet [ no milk , soy , egg , wheat , seafood ( fish and shellfish ) , and peanuts ( peanuts and tree nuts ) ] led to a significant reduction of esophageal eosinophilia . in their pediatric trial , kagalwalla et al . started 35 children on the six - food elimination diet ; 74% of the children had resolution ( < 10 eosinophils / hpf ) on this diet . in adult trials , the success rate is reported to be 50% with the elimination diet and 90 - 95% for the elemental diet ( n gonsalves , personal communication ) . three standard methods are used for food testing : prick skin testing , in vitro specific ige assays and atopy patch tests . in a study on children , diets based on positive specific ige assays had a response rate near 0% when foods were eliminated based purely on the in vitro specific ige assay results . in the same study , this strongly suggests that the food allergy in ee is not strictly ige mediated , consistent with the results with omalizumab . atopy patch testing is designed to look for non - ige - mediated food reactions , presumably t cell - mediated . we have found that the combination of both the prick skin and atopy patch tests , looking for both ige- and non - ige - mediated disease , has been highly successful in the treatment of ee . a food that was negative on both the prick skin and atopy patch tests was unlikely to cause ee , with a predictive value of 90% or more for all foods except milk . additionally , the combination of the skin prick and atopy patch tests resulted in resolution of ee symptoms and normalization of biopsies in 80% of patients [ if any treatment , medical or dietary , is stopped , the symptoms return and esophageal eosinophilia reoccurs with very rare exceptions . it is important to note that there are no current approved medications for the treatment of ee , however , the use of the patients typically swallow inhaled corticosteroids used for asthma in moderate to high doses ( given without use of spacer and avoiding foods / liquids for 30 minutes ) . the goal of this therapy is to deposit steroids in the esophagus leading to apoptosis of the eosinophils and reduction of symptoms . konikoff et al . completed a randomized double - blind placebo - controlled trial of 36 pediatric patients with ee who either refused or failed dietary modification . they reported improved control of symptoms and less eosinophils per high power field ( eosinophils / hpf ) in biopsy in 50% of the patients . the success rate was 50% compared to an 80 - 90% success rate in the open - label trials with fluticasone or budesonide . cromolyn , montelukast ( a leukotriene receptor antagonist ) , and omalizumab ( an anti - ige antibody ) , did not show any histological improvement in open - label clinical trials . at this point , these drugs can not be recommended for ee . a recent open label trial of mepolizumab ( an anti - interleukin ( il)-5 antibody ) showed a significant improvement in four patients , with biopsy improving from 150 to 40 eosinophils / hpf ; however , this was still well above the normal level of 0 eosinophils / hpf . a second approach is to treat the cause of ee by eliminating the appropriate food . an elemental diet has been successful in both pediatric and adult patients , with success rates surpassing 95% . however , due to the poor palatability of these formulas , it is difficult for patients to remain on them . a more directed approach to eliminating the particular food antigen is possible ; two possible ways to remove the food antigen include removing the most common food allergens or removing the allergens based on allergy testing . the first method has been primarily studied by kagalwalla et al . in pediatric patients and by gonsalves in adults ( n gonsalves , personal communication ) . they found that a six - food elimination diet [ no milk , soy , egg , wheat , seafood ( fish and shellfish ) , and peanuts ( peanuts and tree nuts ) ] led to a significant reduction of esophageal eosinophilia . in their pediatric trial , kagalwalla et al . started 35 children on the six - food elimination diet ; 74% of the children had resolution ( < 10 eosinophils / hpf ) on this diet . in adult trials , the success rate is reported to be 50% with the elimination diet and 90 - 95% for the elemental diet ( n gonsalves , personal communication ) . three standard methods are used for food testing : prick skin testing , in vitro specific ige assays and atopy patch tests . in a study on children , diets based on positive specific ige assays had a response rate near 0% when foods were eliminated based purely on the in vitro specific ige assay results . in the same study , the prick skin test had only a slightly better success rate of about 50% . this strongly suggests that the food allergy in ee is not strictly ige mediated , consistent with the results with omalizumab . atopy patch testing is designed to look for non - ige - mediated food reactions , presumably t cell - mediated . we have found that the combination of both the prick skin and atopy patch tests , looking for both ige- and non - ige - mediated disease , has been highly successful in the treatment of ee . a food that was negative on both the prick skin and atopy patch tests was unlikely to cause ee , with a predictive value of 90% or more for all foods except milk . additionally , the combination of the skin prick and atopy patch tests resulted in resolution of ee symptoms and normalization of biopsies in 80% of patients [ 17 - 19 ] . ee is a chronic disorder . if any treatment , medical or dietary , is stopped , the symptoms return and esophageal eosinophilia reoccurs with very rare exceptions . one of the major advances in the past 2 years was the first international gastrointestinal eosinophil research symposium ( figers ) , a consensus meeting of allergists , gastroenterologists , and pathologists that developed clinical recommendations for the diagnosis and treatment of ee . primary clinicopathological disorder of the esophagus with diagnosis made by esophageal biopsy with a finding of 15 eosinophils / hpf in one or more specimens . the report emphasized that gastroesophageal reflux must be aggressively managed prior to endoscopy with a high dose proton pump inhibitor or the patient must have evidence of normal distal esophageal ph as detected by ph probe ; this was based on a case report by ngo and colleagues describing three patients whose esophageal eosinophil count of up to 52 eosinophils / hpf resolved with reflux medications . besides gastroesophageal reflux , clinicians must keep in mind that esophageal eosinophils can be seen in other disease entities , including eosinophilic gastroenteritis ( increased eosinophils throughout the gastrointestinal tract ) , crohn 's disease , collagen vascular disease , hypereosinophilic syndrome , and drug - associated diseases , and are occasionally associated with infections . additional recent studies have indicated that ee is a chronic disease , with less than 10% of patients outgrowing it . the relationship was confirmed in studies in both adults and children , approximately 75% of whom had other atopic diseases ( allergic rhinitis , asthma or atopic dermatitis ) and associations with celiac disease [ 27 - 30 ] and tracheoesophageal fistula . young infants and toddlers typically present with gerd or failure to thrive due to the assumed pain associated with eating . these patients were all diagnosed at an early age and were treated aggressively through avoidance of allergens . because the symptoms of ee do not correlate with endoscopy and histological findings , it is important to use endoscopy for diagnosing and following patients with ee . several articles by the rothenberg and justinich laboratories have made advances in determining the potential mechanism of ee , showing that il-13 and fibroblast growth factor-9 have important roles in the proliferative responses in the esophagus [ 33 - 36 ] . examined the use of infliximab ( an anti - tumor necrosis factor- antibody ) in treating ee , but it had no effect on histological findings . the most recent studies suggest there is a certain phenotype that should be examined carefully for ee . the stereotypical patient is a male caucasian with classic symptoms ( dysphagia or food impaction in adolescents and adults ; abdominal pain in school - age children ; gerd symptoms in young children ) . also , the lack of correlation of symptoms with endoscopy findings indicates the importance of using endoscopy for diagnosing and following patients with ee . management of this disease is primarily through diet as foods are causative in more than 90% of adults and children . the author was a local principal investigator for multi - center studies by ception therapeutics ( rockville , md , usa ) and nutricia north america ( gaithersburg , md , usa ) . Output:	eosinophilic esophagitis is a newer disease entity that has been diagnosed with increasing frequency over the past 10 years . patients present with a variety of symptoms including vomiting , failure to thrive , abdominal pain , dysphagia , and/or food impaction depending on the age of the patient . the diagnosis is confirmed by endoscopy with eosinophilic inflammation localized to the oesophagus , an area typically void of eosinophils .
PubmedSumm118861	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: double crush syndrome is referrs to the coexistence of dual compressions along the course of a peripheral nerve . a proximal compression may lessen the ability of the nerve to withstand a distal one.1 when involving median nerve , the coexistence of carpal tunnel syndrome ( cts ) and cervical radiculopathy is the type of double crush syndrome with the highest frequency.2 except for the nerve roots , any other sites proximal to carpal tunnel along the median nerve can also serve as the proximal compression sites . we present a patient who developed a symptomatic cts after plating of the humeral shaft fracture . a 62 year old woman sustained a closed fracture of right humeral shaft resulting from a car accident ( ota 12a3 ) . we performed the open reduction and internal fixation through an anterolateral approach under general anesthesia and placed a 4.5 mm dynamic compression plate on the lateral aspect of the humerus . the placement of the implants was good except that the tip of the most proximal screw protruding approximately 1 cm through the medial cortex [ figure 1 ] . during in - hospital treatment , the patient recovered without complaining any discomfort of the right hand . 4 weeks postoperatively , however , she began to feel tingling over the thumb , index and middle fingers of the right hand , which was worse at night . when coming to our clinics 3 months postoperatively , she presented a sensory deficit of those fingers . both tinel 's sign over carpal tunnel and phalen 's test were positive , as well as atrophy of the thenar muscles . the neurophysiological study confirmed the clinical suspicion of cts , with a prolonged distal latency and low amplitude of compound muscle action potential , so did the sensory nerve [ figure 2 ] . the criteria for electro - diagnosis of cts included : distal median motor latency > 4.4 ms ; difference between distal motor latency of median and ulnar nerve > 1.1 ms ; difference between distal sensory latency of median and ulnar nerve > 0.2 ms.3 although a transient improvement was observed with night splint treatment , the symptoms recurred after a few weeks . a carpal tunnel decompression was therefore recommended but the patient refused . ( a ) preoperative ( b ) postoperative radiographs of the humerus showing humeral shaft fracture . note that the most proximal screw protrudes through the anteromedial cortex the right median nerve conduction study showed a low amplitude compound muscle action potential ( a ) and sensory nerve action potential ( b ) with a prolonged latency . for motor nerve study , recording electrode was over the abductor pollicis brevis muscle , with stimulation at the wrist radial to palmaris longus . for sensory nerve study , amp , amplitude ; lat , latency at 16 months postoperatively , the patient asked for removal of the implants . during the operation , we observed that the tip of the protruding screw twisted the median nerve with scar tissues . extensive neurolysis around the median nerve was not performed , because we did not expect relief of symptoms of cts after removal of the implants . at 2 weeks later , however , the patient experienced a significant relief of the tingling over fingers . at last review , 6 months after the implants removal , her sensations returned to near normal with full movement of the fingers . although mild thenar atrophy was still present , the patient remained asymptomatic and denied additional carpal tunnel decompression surgery as she had no great difficulty in carrying out her daily activities . a humeral shaft fracture is usually associated with radial nerve palsy , a review by shao et al . reported an average rate of 11.8%.4 on the contrary , the injuries of the median nerve with fractures of the humeral shaft are extremely unusual , because it is protected from direct contact with bone by several muscles including the brachialis and coracobrachialis . macnicol reported a case of the median nerve palsy after a humeral shaft fracture in a 10-year - old girl , who fell from a pony.5 veilleux and richardson also reported a case of median neuropathy associated with a humeral neck fracture.6 our case developed a cts 4 weeks after plating of the humeral shaft fracture . if it was not a coincidence , several potential causative factors might be involved in the presence of the cts . the postoperative immobilization decreased the use of the muscle pump and caused an additional entrapment of the median nerve . however , the immobilization or swelling could not explain the rapid improvement of the numbness after removal of the implants . the clinical effects caused by intraoperative injuries , such as drilling , surgical stretch or compression , would usually be noticed immediately postoperative . therefore , we speculated that the symptoms of cts were caused by the implants of the humeral shaft , i.e. a double crush syndrome might account for it . the theory of double crush syndrome emphasizes that the damage produced by the dual compression exceeds the additive damage caused by each low grade compression.2 although there were still some controversies about the mechanism of coexistence of cts and cervical radiculopathy , the theory of double crush syndrome had been proved in the model of dual compressions on a single nerve pathway.78 regarding this case , the tip of a screw protruded 1 cm through the medial cortex at the middle of the humerus shaft after fracture plating , where the median nerve courses distally . it was extremely likely that the protruding screw produced a subclinical compression of the median nerve . the intraoperative exploration during the implants removal also observed the contact between the screw and nerve . although the proximal compression was very slight , the susceptibility to compression of the median nerve might be increased at the carpal tunnel level . the scar formation surrounding the humerus limited the mobility of the nerve and resulted in further deterioration of the proximal compression . ultimately , the additive effect of these factors converted a subclinical cts into a clinically evident one and a double crush syndrome of the median nerve developed . in management of double crush syndrome , whether proximal or distal compression should be treated first , is still controverial , given that there are few reported series with specific scrutiny of both conditions.9 in this case , it would have been more logical to do a carpal tunnel decompression if the patient agreed . however , most chinese patients prefer to have the implants removed after the fracture . the incomplete recovery of the thenar atrophy may be related to the long period of the compression . the picture of the screw entangling the nerve and causing nerve compression was not presented , as we did not expect that the implants removal could relieve the cts symptoms . this study described a case of symptomatic cts caused by the protruding screw in arm . placement of any screw with excessive length should be avoided during the internal fixation of the humeral shaft fracture . Output:	median nerve injury is rarely associated with the humeral shaft fracture . a sixty two year old woman with a displaced humeral shaft fracture , developed a symptomatic carpal tunnel syndrome after plating with a screw protruding medially . 16 months later , the implants were removed and the symptoms gradually improved without carpal tunnel release surgery . a double crush syndrome resulted due to the proximal compression by the medially protruding screw and the distal compression by carpal tunnel . the proximal decompression produced by removal of the screw led to relief of the symptoms .
PubmedSumm118862	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: the determination of a biomolecule 's complete three - dimensional structure provides invaluable information about the molecule 's function , and how that function might be modulated . unfortunately , determining protein or nucleic - acid structures from the molecules themselves is difficult owing to physical impediments . likewise , accurate computational prediction of such structures from physical principles remains computationally intractable owing to the overwhelming number of degrees of freedom in the system . techniques that can determine constraints on the potential molecular conformations can dramatically improve the chances of determining structures with both measured and predictive methods . one possible method for predicting physical proximity is to examine large families of sequences that have presumably similar structures , and to catalog positional pairs that show correlation between the identities of the residues occupying them . this calculation produces a four - dimensional matrix of positions , identities , related positions and strengths of relationship . for a small rna molecule of 80 nt , this 4d matrix contains 160 000 values , while a small protein of 300 amino acids produces a cross - correlation matrix containing 39 690 000 values . since there is no single value or distinctly definable pattern amongst these values that signals a structural relationship , an abstraction that allows the expert researcher to visualize , interpret and query the matrix is clearly necessary ( ) . mavl / stickwrld was developed to visualize interpositional dependencies within nucleic acid and amino acid sequence alignments ( 1,2 ) . in this representation , a positional weight matrix representing the alignment is wrapped around a cylinder by placing spheres for each identity and position . the diameters of the spheres are proportional to the percentage frequency of the corresponding identity . the diameter of the sticks is based on the over - representation or under - representation of sequences sharing these identities as compared with a weight - matrix - based expectation for the sequences as a family . this visualization method allows the researcher to detect patterns of pairwise positional dependencies easily , and comment on possible structural implications of these observations . in this paper , we present a complete rewrite of mavl / stickwrld in java3d ( ) . the new implementation has three significant areas of improvement over the vrml version : enhanced real - time user interaction ; clustering of residues by aggregate physicochemical properties and availability of pre - calculated stickwrld wrlds for all families in the pfam database ( 3 ) . our java3d implementation leaves the computationally intensive calculation of the complete interpositional correlation matrix on the server , but moves the selection of features for display , to the client applet running on the user 's computer . it is no - longer necessary to completely re - compute the correlation matrix to change display preferences . therefore the user interface is no longer limited to a static graph with pre - applied statistical and display parameter choices . instead , the various stickwrld statistical parameters ( tr , the global over / underpopulation threshold ; pr , the per - edge overpopulation threshold ; nr , the per - edge underpopulation threshold ; and alpha , the edge - significance threshold ) , and display parameters such as residue coloring and grouping can be adjusted by the user on - the - fly . this allows the parameters to be adjusted to suit the complexity of the alignment being visualized , and the user can now toggle between coarse visualization parameters to quickly explore and locate interesting features of an alignment , and fine parameters to investigate detailed aspects of the relationship . to allow the system to more intuitively deal with the potentially weak relationships amongst poorly constrained sequences , this allows , for example , the conserved residue properties and interpositional requirements of distant homologs to be discovered , even in the absence of specifically conserved residues . residues can currently be grouped by hydropathy , charge and volume , and the relationship between these aggregate properties at each position visualized , just as the specific sequence identities can be . using this option in many protein families results in the discovery of correlated physical properties , even when the contributing residue identities fall below the significance threshold , or are obscured by other more dramatic individual - residue relationships . finally , we are interested in the distribution of the variety of interpositional relationships highlighted by mavl / stickwrld , amongst known sequence families . to facilitate access to this information , and to make it easier for researchers to examine popular sequence families , we have pre - computed stickwrld wrlds for the complete pfam database of sequence families . the pfam alignments , and the wrlds generated from them , are available directly from the mavl / stickwrld java interface . we currently house 7868 sequence families ( the average number of sequences per family is 23 and average sequence length is 227 ) from pfam , and we update the stickwrld database regularly . some interesting statistics have come out of our examination of this data collection : the average number of possible correlations per family is approximately 1 000 000 . on average , 5% of these display over / underpopulations > 10% of expected population ( tr > 0.10 ) . however , > 60% of those with tr > 0.10 have a significance better than 0.0001 . this strongly suggests that many of the relationships highlighted by mavl analysis are biologically relevant , rather than simple random outliers discovered by the massive number of correlations considered . the above improvements in the implementation result in fast , easy and accurate examinations of sequence families . enhanced user interaction and availability of pre - calculated stickwrld wrlds for pfam alignments provide fast and convenient analysis . grouping of the residues based on physicochemical properties supplies more information on conserved patterns within families . applying mavl / stickwrld to a typical protein domain results in improved understanding of the interacting residues , and the physical properties required to maintain structure or function . figure 1 shows stickwrld representations and corresponding three - dimensional protein structures for the pfam family of integrin alpha cytoplasmic regions ( pdb 1m8o shown ) . this family contains the short cytoplasmic region of integrin alpha chains , and has small , strongly conserved -helix , followed by a generally acidic region ( 4,5 ) . mavl / stickwrld analysis ( figure 1a ) suggests that there are two alternative preferred sequences within the family { r9 p10 p11 q12 e13 } or { y9 k10 m12}. that is , while the canonical structure contains an -helix , terminating in r9 and broken by prolines at p10 and p11 , there is an alternate sequence motif that contains neither p10 nor p11 , but instead a preferred tyrosine , lysine , methionine triplet at { 9 , 10 , 12}. a tutorial on reading the stickwrld diagrams produced by the java version is available from the mavl / stickwrld help - files page ( ) . furthermore , grouping of the residues by charge , to elucidate bulk - property - related propensities ( figure 1b , 1c ) reveals more molecular preferences of the distinct sequence subfamilies . the turn following the -helix of the cytoplasmic domain appears to be stabilized by either 5 residues following the pattern { 9 + , 10np , 11np , 12p , 13 } or 8 residues { 8 + , 9p , 10 + , 11 , 12np , 13np , 14p , 15 } ( + : positively charged , :negatively charged , p : polar , np : nonpolar ) there is also a preference in the first pattern for a slightly polar residue at 2 , and against a non - polar residue at this position . a high - resolution copy of figure 1 , as well as links to live versions of the java stickwrld diagram are available from the mavl / stickwrld help - files page ( ) . strongly conserved ( consensus ) residues of this small domain are colored and labeled in figure 1d , and participate in the 10-residue n - terminal -helix of the domain . acidic , and do not capture the sequence or property requirements , or suggest their involvement in stabilizing the hairpin . it is clear that the positively charged arginine and negatively charged glutamate are brought together by the hairpin , and can act in concert to stabilize the hairpin with the support of other polar and non - polar residues . while crystal or solution structures are not available for any non - proline - motif integrin alpha domains , we predict that the alternative positive residues at 8 and 10 , and negative residues at 11 and 15 will be found to interact similarly to stabilize the domain structure . mavl / stickwrld 's new java interface provides rapid exploration of alignment properties and insight into potential structural requirements that are embedded in the sequence identities . the analysis and visualization method has proven both intuitive and accurate for predicting likely structural features in protein and nucleic acid families for which representative crystal or solution structures are known . we are developing additional utilities to assist the researcher by providing automatic suggested partitions of sequence families into subgroups , and are actively extending our pre - computed analysis database so that researchers may mine other interesting structural features from the pfam families database . stickwrld graph representations of the integrin alpha cytoplasmic domain family alignments , and a corresponding domain solution structure . ( a ) shows interpositional correlations within the family in the form of a default stickwrld graph ; [ b ( detail ) and c ( overview ) ] show correlations obtained when residues are grouped by charge ( red positive , blue negative , cyan polar , tan slightly - polar , green non - polar , grey gap ) ; ( d ) illustrates the position of strongly conserved residues on the domain 's structure ( e ) displays strongly correlating residues based on mavl / stickwrld analysis of the aligned members of the domain . Output:	the increasing availability of structurally aligned protein families has made it possible to use statistical methods to discover regions of interpositional dependencies of residue identity . such dependencies amongst residues often have structural or functional implications , and their discovery can supply valuable constraints that assist in the refinement of measured , or predicted molecular structure assignments . multiple alignment variation linker ( mavl ) and stickwrld [ w. ray ( 2004 ) nucleic acids res . , 32 , w59w63 ] were developed to analyze and visualize nucleic acid and protein alignments , to discover and illuminate position / location relationships to the user . the original system analyzed users ' data from a web - form submission and presented the user with a static vrml diagram describing their data . we are pleased to report that mavl / stickwrld has been completely redesigned and rewritten . mavl / stickwrld now functions as a platform - independent java applet , with real - time dynamic controls that enable much more intuitive exploration and interaction with the data . the system has also been upgraded to enable visualization of a range of aggregate residue properties , and an extensive database of pre - computed stickwrld diagrams based on pfam families is now available directly from the interface . the java stickwrld applet is available via the www at .
PubmedSumm118863	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: the barcelona clinic liver cancer ( bclc ) treatment guidelines divide patients diagnosed with hepatocellular carcinoma ( hcc ) into very early , early , intermediate , advanced and terminal stages . while very early and early - stage patients would be candidates for curative therapy , those with intermediate or advanced stage are not . unfortunately , more than 80% of hcc patients are diagnosed at an advanced stage , with poor prognosis and a lack of effective therapies . recently , a multicenter , randomized , double - blind , placebo - controlled , phase 3 trial in western countries has shown that the median overall survival and time to progression of patients treated with sorafenib were nearly 3 months longer than for placebo treatment . thus , the bclc staging classification and treatment strategy recommends sorafenib as a standard treatment of advanced hcc . the bclc advanced stage involves a wide spectrum of diseases : vascular invasion ( portal vein thrombosis ) , lymph node metastasis , distant metastasis , and mildly symptomatic performance status ( eastern cooperative oncology group grade 1/2 ) . although sorafenib is a standard of care , its limited benefit urges further investigation of new approaches . particularly in liver - confined disease , a liver - directed therapy is worth serious consideration . before the introduction of sorafenib , our group developed a protocol - based hepatic arterial concurrent chemoradiotherapy ( ccrt ) consisted of local radiotherapy ( rt ) and concurrent 5-fluorouracil ( 5-fu ) hepatic arterial infusion chemotherapy ( haic ) , followed by monthly haic ( 5-fu and cisplatin ) for 6 months . even though sorafenib was introduced to medical practice in 2009 , its high cost has been a major barrier to routine clinical use in korea . therefore ccrt has continued to be used in our clinic . a pilot trial reported in 2008 showed a response rate of 45% , a 3-year overall survival rate of 24.1% , and a median survival time of 13.1 months , which exceeds the previously reported 6 months more than 2-fold . intrahepatic - outfield and extrahepatic metastases were frequently seen after ccrt . to improve the therapeutic outcome of hcc patients treated with ccrt , , we aimed to analyze patterns of failure and to find out predictive clinical factors in hcc treated with a liver - directed therapy of ccrt . medical records of 138 hcc patients treated with ccrt in severance hospital between may 2001 and november 2009 were reviewed retrospectively . the patient , tumor and treatment characteristics of the study group are shown in table 1 . the median patient age was 55 years ( range , 3379 years ) , and the ratio of males to females was 7:1 . the number of patients with modified international union against cancer ( uicc ) stage t3n0m0 and t4n0m0 was 24 ( 17.4% ) and 86 ( 62.3% ) , respectively . while ccrt was applied to locally advanced hcc with t3 and t4 stage , 20 patients ( 14.5% ) with t2 stage were also included due to large tumors of 10 cm . a total of 104 patients ( 75.4% ) were newly diagnosed as hcc ( primary treatment group ) , and 34 patients ( 24.6% ) had been treated with another treatment modality before ccrt ( recurrence treatment group ) . table 1.patient characteristicscharacteristicsno . of patients ( % ) age ( median year)55 ( range , 3379 ) < 5037 ( 26.8 ) 50101 ( 73.2)gender male120 ( 87.0 ) female18 ( 13.0)viral type b116 ( 84.1 ) c9 ( 6.5 ) non - b , non - c13 ( 9.4)child - pugh class a125 ( 90.6 ) b13 ( 9.4)icg r15 ( median % ) 10.8 ( range , 1.470.9)modified uicc stage ii t2n0m020 ( 14.5 ) iii t3n0m065 ( 47.1 ) iva t4n0m041 ( 29.7 ) t2n1m01 ( 0.7 ) t3n1m010 ( 7.2 ) t4n1m01 ( 0.7)portal vein thrombosis no61 ( 44.2 ) yes77 ( 55.8)lymph node metastasis no126 ( 91.3 ) yes12 ( 8.7)pre - ccrt afp ( median iu / ml)570.4 ( range , 1.088 336.5 ) < 20060 ( 43.5 ) 20078 ( 56.5)pre - ccrt pikva - ii ( median mau / ml)1641 ( range , 10.02 000.0 ) < 6017 ( 12.6 ) 60118 ( 87.4)pre - ccrt treatment history no ( primary treatment group)104 ( 75.4 ) yes ( recurrence treatment group)34 ( 24.6)contents of pre - ccrt treatment tace19 ( 55.9 ) tace , internal rt ( holmium-166)4 ( 11.8 ) tace , rfa3 ( 8.8 ) tace , surgery1 ( 2.9 ) tace , systemic chemotherapy1 ( 2.9 ) tace , internal rt ( holmium-166 ) , sorafenib1 ( 2.9 ) rfa1 ( 2.9 ) intra - arterial chemotherapy2 ( 5.9 ) internal rt ( holmium-166)1 ( 2.9)radiotherapy technique 3d crt113 ( 81.9 ) imrt25 ( 18.1)total dose ( median gy)45.0 ( range , 45.064.8)dose / fraction ( median gy)1.8 ( range , 1.83.0)icg = indocyanine green , uicc = international union against cancer , ccrt = concurrent chemoradiotherapy , tace = transarterial chemoembolization , rt = radiation therapy , rfa = radiofrequency ablation , afp = alpha - feto - protein , pivka - ii = protein induced by vitamin k absence , 3d crt = three - dimensional conformal radiation therapy , imrt = intensity - modulated radiation therapy.systemic adriamycin / cisplatin.cisplatin 1 , fluorouracil / cisplatin 1 . patient characteristics icg = indocyanine green , uicc = international union against cancer , ccrt = concurrent chemoradiotherapy , tace = transarterial chemoembolization , rt = radiation therapy , rfa = radiofrequency ablation , afp = alpha - feto - protein , pivka - ii = protein induced by vitamin k absence , 3d crt = three - dimensional conformal radiation therapy , imrt = intensity - modulated radiation therapy . the ccrt protocol in our institution consists of ccrt followed by hepatic arterial chemotherapy , as described in our previous study . before ccrt was started , a percutaneous hepatic arterial catheter ( chemoport ) was inserted , then drug distribution was simulated by hepatic angiography through the chemoport . concurrent continuous - infusion hepatic arterial 5-fu ( at a dose of 500 mg / day ) was delivered during the first and last weeks of rt through the chemoport . one month after ccrt , haic with 5-fu ( at a dose of 500 mg / m for 5 h on days 13 ) and cisplatin ( at a dose of 60 mg / m for 2 h on day 2 ) were administered every 4 weeks for 312 cycles , according to tumor response ; these courses are termed repeated haic. repeated haic was stopped if disease progression was shown . three - dimensional conformal radiotherapy ( 3d - crt ) was performed on 81.9% of patients , and intensity - modulated radiotherapy was applied in the remaining 18.1% . the median radiation dose was 45 gy ( range , 4564.8 gy ) , and the median dose per fraction was 1.8 gy ( range , 1.82.95 gy ) . the median pre - ccrt serum level of the liver tumor marker alpha - fetoprotein ( afp ) was 570.4 iu / ml ( range , 1.088 336.5 ) , and 78 patients had levels > 200 iu / ml . the median pre - ccrt level of the second marker , prothrombin induced by vitamin k absence ( pivka - ii ) , was 1641 mau / ml ( range , 10.02000.0 ) , and 118 patients had serum levels > 60 mau / ml . tumor responses were evaluated using modified response evaluation criteria in solid tumors , defining the viable tumor by its uptake of contrast agent in the arterial phase of dynamic computed tomography or magnetic resonance imaging . the tumor response was categorized as complete response ( cr ) , i.e. the disappearance of any intratumoral arterial enhancement in all targets ; partial response ( pr ) , at least a 30% decrease in the sum of diameters of viable target lesions ; progressive disease ( pd ) , an increase of at least 20% in the sum of the diameters of viable target lesions ; or as stable disease ( sd ) , any cases that do not qualify for either pr or pd . patterns of failure were categorized into three groups : infield failure , intrahepatic - outfield failure , and extrahepatic failure . infield failure was defined as progression of the tumor within the radiation field that covered the planning target volume . intrahepatic failure was defined as progression of the tumor within the liver but outside of the radiation field . . overall survival , progression - free survival ( pfs ) , and clinical factors influencing each failure were analyzed using the kaplan - meyer method . multivariate analysis was performed using the cox - proportional hazard model , and p values were calculated from the log - rank test . median follow - up time was 10.4 months ( range , 0.492.4 ) in all patients and 35.2 months ( range , 13.992.4 ) in surviving patients . the median overall survival time from the end of rt was 11.1 months , and the survival rates at 1 and 2 years were 46.1% and 27.9% , respectively ( fig . 1 ) . at the last follow - up , 115 patients ( 83.3% ) had died , the status of 2 ( 1.4% ) was unknown , and 21 ( 15.2% ) were still alive . of the patients who were alive , 16 patients had no evidence of disease , and five were living with disease . the median pfs for infield , intrahepatic - outfield and extrahepatic failures were 22.4 , 18 and 21.5 months , respectively . the 1-year pfs rates for the same failure groups were 72.2 , 62.1 and 56.6% , respectively . the 1-year survival rate was 46.1% and median overall survival ( os ) was 11.1 months . progression - free survival rates at 1 year after rt were 72.2% , 62.1% , and 56.6% for infield , intrahepatic - outfield , and extrahepatic failures , respectively . the median pfs for the same failure groups were 22.4 , 18 , and 21.5 months , respectively . the 1-year survival rate was 46.1% and median overall survival ( os ) was 11.1 months . progression - free survival rates at 1 year after rt were 72.2% , 62.1% , and 56.6% for infield , intrahepatic - outfield , and extrahepatic failures , respectively . the median pfs for the same failure groups were 22.4 , 18 , and 21.5 months , respectively . the treatment response was evaluated at 3 months after finishing rt in the ccrt protocol ( table 2 ) . follow - up , treatment failure occurred in 106 patients ( 76.8% ) and 46 patients ( 33.3% ) had infield failure . the sites of extrahepatic failure , in order of frequency , were lung , distant lymph node , bone , peritoneal seeding , adrenal gland , pleura and brain . ( % ) complete response4 ( 2.9)partial response77 ( 55.8)stable disease45 ( 32.6)progressive disease12 ( 8.7 ) fig . patterns of failure were categorized into three groups ; infield , intrahepatic - outfield , and extrahepatic failures . at 3 months after concluding rt in the ccrt protocol , treatment failures occurred in 47 patients ( 34.0% ) . patterns of failure were categorized into three groups ; infield , intrahepatic - outfield , and extrahepatic failures . at 3 months after concluding rt in the ccrt protocol , treatment failures occurred in 47 patients ( 34.0% ) . about half of treatment failure was combined with other categories of failure such as infield with intrahepatic - outfield failure , or infield with extrahepatic failure ; 7 of 12 infield failures , 13 of 26 intrahepatic - outfield failures , and 14 of 27 extrahepatic failures . the association of clinical factors involving age , sex , stage , portal vein thrombosis , treatment history and pre - ccrt tumor marker level were analyzed by univariate and multivariate analysis for prognostic significance for pfs ( table 3 and fig . the pfs for infield failure was improved in patients in the primary treatment group compared with patients in the recurrence treatment group ( at 2 years after rt , pfs of 53.5% vs 29.6% , p = 0.035 ) . other clinical factors including t stage , tumor size and rt dose were not associated with local control . both the elevation of pre - ccrt afp levels ( 200 iu / ml ) and pivka - ii ( 60 mau / ml ) were significant factors for intrahepatic - outfield failure ( at 2 years after rt , pfs 43.5% vs 38.7% , p = 0.005 ) . for extrahepatic failure , an age of < 50 years was a significant factor ( p = 0.007 ) , as were biomarker levels of afp 200 iu / ml and pivka - ii 60 mau / ml ( p = 0.003 ) . in multivariate analysis , the levels of the two biomarkers were not associated with intrahepatic - outfield failure , but they were the only significant factors identified as associated with extrahepatic failure . table 3.risk factors of progression - free survival ( pfs)a ) univariate analysislocal failuredistant failureinfield failureintrahepatic - outfield failureextrahepatic failureno.2-year pfs ( % ) p - valueno.2-year pfs ( % ) p - valueno.2-year pfs ( % ) p - valueage ( y ) < 503754.80.9073726.60.3093726.20.007 5010144.510143.510148.9stage ii2059.80.4742040.70.6102060.80.116 iii - iv11846.311840.511840.2portal vein thrombosis no6155.20.2336140.60.2756136.60.443 yes7738.57739.37752.3pre - ccrt treatment history primary treatment group10453.50.03510438.50.89210441.80.314 recurrence treatment group3429.63441.63448.3pre - ccrt afp ( iu / ml ) < 2006043.50.9166042.70.0626044.80.087 2007853.87838.87843.7pre - ccrt pivka - ii ( mau / ml ) < 601751.40.9621753.20.1601760.50.177 6011844.911836.211840.2pre - ccrt afp & pivka - ii 200 & 606750.30.4656738.70.0056742.40.003 < 200 & /or failurehr95% cip - valuehr95% cip - valuehr95% cip - valueage0.7420.3601.5310.4200.8530.4801.5180.5890.6800.3821.2090.189 50stage1.0360.4312.4930.9370.8780.4261.8100.7241.8690.8454.1340.122 iii ivportal vein thrombosis1.3860.7252.6510.3241.2670.7292.2030.4010.6690.3981.1260.131 yespre - ccrt treatment history2.1901.1324.2350.0201.1980.6772.1200.5360.8580.4581.6060.631 recurrence treatment grouppre - ccrt afp ( iu / ml)0.4440.0962.0480.2981.0450.2314.7260.9540.2420.0461.2760.094 200pre - ccrt pivka - ii ( mau / ml)0.7420.2502.2070.5921.4220.4234.7840.5690.6020.2231.6220.315 60pre - ccrt afp & pivka - ii 200 and 602.5110.48512.9970.2721.7400.3538.5870.4966.9491.21939.6140.029pfs = progression - free survival , ccrt = concurrent chemoradiotherapy , afp = alpha - feto - protein , pivka - ii = protein induced by vitamin k absence ; hr , hazard ratio ; ci , confidence interval . ( a ) pfs of infield failure was improved in patients treated with ccrt as the initial treatment ( primary treatment group ) . a history before pre - ccrt treatment was also identified as a significant factor in multivariate analysis ( p = 0.020 ) . ( b ) both the elevation in the pre - ccrt levels of afp ( 200 iu / ml ) and pivka - ii ( 60 mau / ml ) were significant factors for intrahepatic - outfield failure . however , changes in the levels of these tumor markers were not significant in multivariate analysis ( p = 0.496 ) . ( c , d ) patients < 50 years of age and with incremental changes in the levels of pre - ccrt afp ( 200 iu / ml ) and pivka - ii ( 60 mau / ml ) showed poorer pfs for extrahepatic failure . incremental changes in the levels of the pre - ccrt tumor marker were the only significant factor identified in multivariate analysis ( p = 0.029 ) . risk factors of progression - free survival ( pfs ) pfs = progression - free survival , ccrt = concurrent chemoradiotherapy , afp = alpha - feto - protein , pivka - ii = protein induced by vitamin k absence ; hr , hazard ratio ; ci , confidence interval . progression - free survival ( pfs ) of treatment failure by risk factor . ( a ) pfs of infield failure was improved in patients treated with ccrt as the initial treatment ( primary treatment group ) . a history before pre - ccrt treatment was also identified as a significant factor in multivariate analysis ( p = 0.020 ) . ( b ) both the elevation in the pre - ccrt levels of afp ( 200 iu / ml ) and pivka - ii ( 60 mau / ml ) were significant factors for intrahepatic - outfield failure . however , changes in the levels of these tumor markers were not significant in multivariate analysis ( p = 0.496 ) . ( c , d ) patients < 50 years of age and with incremental changes in the levels of pre - ccrt afp ( 200 iu / ml ) and pivka - ii ( 60 mau / ml ) showed poorer pfs for extrahepatic failure . incremental changes in the levels of the pre - ccrt tumor marker were the only significant factor identified in multivariate analysis ( p = 0.029 ) . although data was not shown , we also analyzed the clinical factors related to overall survival . t3/4 stage , child - pugh class b , infield failure at 3 months after finishing rt and both the elevation of pre - ccrt afp levels ( 200 iu / ml ) and pivka - ii ( 60 mau / ml ) were significant factors in multivariate analysis . neutropenia grade 3 and thrombocytopenia grade 3 were observed in 17 and 23 patients , respectively . of the 138 patients , 20 had died 3 months after ccrt , and hepatic failure was the cause of death in 13 patients . hepatic failure seemed to have resulted from complex factors involving treatment and disease progression . ( % ) neutropenia14 ( 10.1%)3 ( 2.2%)anemia2 ( 1.4%)3 ( 2.2%)thrombocytopenia21 ( 15.2%)2 ( 1.4%)ast elevation19 ( 13.8%)8 ( 5.8%)alt elevation11 ( 8.0%)2 ( 1.4%)bilirubin elevation5 ( 3.6%)11 ( 8.0%)gi mucositis , ulcer5 ( 3.6%)0ast = aspartate transaminase , alt = alanine aminotransferase , gi = gastrointestinal . toxicity during ccrt and the following 3 months ast = aspartate transaminase , alt = alanine aminotransferase , gi = gastrointestinal . liver - directed therapy , consisting of local radiotherapy and concurrent haic , has been demonstrated as prolonging survival in patients with liver - confined hcc [ 4 , 69 ] . ben - josef et al . performed high - dose 3d - crt ( median 60.75 gy in 1.5 gy per fraction , twice daily , range 4090 gy ) with concurrent haic with floxuridine ( 0.2 mg / kg / day ) . out of 128 patients in their study , 35 had hcc and showed amedian overall survival of 15.2 months . han and seong et al . used concurrent 5-fu haic ( 500 mg / day ) and 3d - crt ( 45 gy in 25 fractions ) , followed by monthly haic . the median survival time of 40 patients with advanced but liver - confined hcc was 13.1 months and the median for pfs was 6 months . although lack of a phase iii randomized study excludes this approach as a standard of care for advanced hcc , the therapeutic outcome seems promising with a longer survival time compared with that for sorafenib treatment , suggesting that this would be worthy of active investigation for a subgroup of advanced hcc patients . in our study , the median pfs was 22.4 , 18 and 21.5 months for infield , intrahepatic - outfield and extrahepatic failures , respectively . treatment failure still remains to be overcome , particularly intrahepatic - outfield and extrahepatic failures . patients with sufficiently high pre - ccrt serum levels of the two biomarkers afp and pivka - ii showed significantly longer pfs . patients treated with other modalities before ccrt , most frequently tace ( 85.2% ) , had worse infield pfs . however , tace frequently fails to induce complete necrosis , and this may result in residual viable tumor [ 10 , 11 ] . the mechanism of tace is extensive ischemic necrosis by hepatic artery obstruction with embolic material . in this process the latter stimulates the proliferative activity of intratumoral endothelial and tumor cells in the residual hcc after tace [ 11 , 12 ] , which can further induce resistance to either chemotherapy or radiotherapy . the lung is the most common site of extrahepatic metastasis , and an increased risk of lung metastasis after tace has been reported . since vascular endothelial growth factor ( vegf ) is a key factor in angiogenesis , an increase in vegf levels after tace may induce development of collateral blood vessels , nourishing the surviving residual tumor tissue [ 10 , 13 , 14 ] . a possible relationship between vegf levels and treatment failure has been investigated in patients treated by tace [ 10 , 13 ] . this relationship between vegf levels and treatment failure might also be relevant in patients treated with ccrt . in our previous reports , addition of rt improved tumor response and survival both for patients with tace failure and for patients with incomplete tace [ 1517 ] . a history of pre - ccrt treatment was identified as a risk factor for infield failure , suggesting a need for more intensified local treatment for this recurrence treatment group . in this regard , the dose of 45 gy in our ccrt protocol needs to be escalated according to the patients ' subgroup . subgroup analysis was done for patients with or without a history of pre - ccrt treatment . median pre - ccrt afp levels were 664.5 iu / ml in the primary treatment group and 527.6 iu / ml in the recurrence treatment group , and the median pre - ccrt pivka - ii levels were 2000.0 mau / ml and 610.0 mau / ml , respectively . in the primary treatment group , elevation of afp and pivka - ii was a significant factor in outfield and extrahepatic pfs ( p = 0.002 and 0.003 , respectively ) . however , the factor was not significant in the recurrence treatment group ( p = 0.171 and 0.07 , respectively ) . levels of both afp and pivka - ii before ccrt were associated with extrahepatic failure . the serum indicators afp and pivka - ii are the most commonly used tumor markers in hcc , and it is well known that an hcc with high levels of afp and pivka - ii is associated with more aggressive tumor behavior , e.g. large numbers of tumors , frequent vascular invasion , early intrahepatic and distant metastasis , and poor prognosis [ 1921 ] . in our study , elevation of only one of the biomarkers was not significant for treatment failure , but elevation of pre - ccrt levels of both was significant . as shown in fig . 3d , differences in the survival curves according to the pre - ccrt tumor markers were marked in early period of follow - up . therefore , pre - ccrt levels of tumor markers could be helpful for predicting early failure . since our protocol - based ccrt consisted of local rt and regional chemotherapy through haic our results suggest that systemic treatment is necessary for a subgroup of patients . in this study , we have identified risk factors for treatment failure : history of pre - ccrt treatment , as a factor associated with infield failure ; and elevation of both afp and pivka - ii levels before ccrt , as a risk factor for extrahepatic failure . this suggests that more intensified treatment is required for the patients presenting risk factors ; intensification of local treatment for those with a past treatment history , and more effective systemic treatment for those with elevated serum tumor markers . since sorafenib is the only recommended systemic agent at present , a novel approach combining sorafenib and ccrt needs further investigation treatment failure was frequent in hcc patients treated with a liver - directed therapy of ccrt , more commonly intrahepatic - outfield and extrahepatic failures than infield failure at 3 months after rt . a history of pre - ccrt treatment , as well as levels of pre - ccrt tumor markers , were identified as risk factors that can predict treatment failure . this study was supported by a grant from the korean health technology r&d project , ministry of health and welfare , republic of korea ( a121982 ) . Output:	before the sorafenib era , advanced but liver - confined hepatocellular carcinoma ( hcc ) was treated by liver - directed therapy . hepatic arterial concurrent chemoradiotherapy ( ccrt ) has been performed in our group , giving substantial local control but frequent failure . the aim of this study was to analyze patterns of failure and find out predictive clinical factors in hcc treated with a liver - directed therapy , ccrt . a retrospective analysis was done for 138 hcc patients treated with ccrt between may 2001 and november 2009 . protocol - based ccrt was performed with local radiotherapy ( rt ) and concurrent 5-fluorouracil ( 5-fu ) hepatic arterial infusion chemotherapy ( haic ) , followed by monthly haic ( 5-fu and cisplatin ) . patterns of failure were categorized into three groups : infield , intrahepatic - outfield and extrahepatic failure . treatment failure occurred in 34.0% of patients at 3 months after rt . infield , intrahepatic - outfield and extrahepatic failure were observed in 12 ( 8.6% ) , 26 ( 18.7% ) and 27 ( 19.6% ) patients , respectively . median progression - free survival for infield , outfield and extrahepatic failure was 22.4 , 18 and 21.5 months , respectively . for infield failure , a history of pre - ccrt treatment was a significant factor ( p = 0.020 ) . pre - ccrt levels of alpha - fetoprotein and prothrombin induced by vitamin k absence or antagonist - ii were significant factors for extrahepatic failure ( p = 0.029 ) . treatment failures after ccrt were frequent in hcc patients , and were more commonly intrahepatic - outfield and extrahepatic failures than infield failure . a history of pre - ccrt treatment and levels of pre - ccrt tumor markers were identified as risk factors that could predict treatment failure . more intensified treatment is required for patients presenting risk factors .
PubmedSumm118864	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: thyroid hormone levels drop down in starvation and in severe illness without detectable clinical effect of hypothyroidism . this condition was generally known as euthyroid sick syndrome , but was later renamed as nonthyroidal illness syndrome ( ntis ) . ntis is evidenced by low levels of thyroxines and normal or low levels of thyroid - stimulating hormone ( tsh ) and elevated reverse tri - iodothyronine ( rt3 ) level . clinical features of hypothyroidism do not develop within even 2 - 3 weeks , but require much longer period for expression . ramrez et al . studied patients receiving chronic hemodialysis and found a high prevalence of goiter ( 58% ) and low serum tetra - iodothyronine ( t4 ) , t3 , and tsh levels . however , rt3 levels were not elevated in patients with end stage renal disease ( esrd ) . the low levels of thyroid hormones may be due to decreased peripheral de - iodization of t4 and low levels of hormone binding proteins . the nonthyroidal illness serves to defend protein loss and an attempt to supplement hormone causes excess protein loss . the kidneys preserve iodine in patients suffering from esrd and prevalence of goiter and hypothyroidism was observed high in patients with esrd compared with the general population in iodine deficient region . hyperthyroidism is uncommon in patients receiving dialysis , but sporadic case reports are available since 1980 . a 28-year - old female reported in march 2005 for evaluation of renal dysfunction noted during her first pregnancy . she developed bilateral pedal edema , hypertension and proteinuria during the third trimester of the first pregnancy in 1998 . she underwent caesarean section at 8 month of gestation , indication being accelerated hypertension . on evaluation 2 months after delivery , she was found to have persistent hypertension , proteinuria , and elevated serum creatinine ( 1.72 mg / dl ) . tests for hiv , hepatitis b and c were negative . screening tests for systemic lupus erythematosus were found negative . kidney biopsy showed focal glomerular sclerosis with an increase in the mesangial matrix and tubular atrophy , suggestive of focal segmental glomerulosclerosis . she was treated with oral prednisolone , but developed pain in both hip joints after 5 months . regional magnetic resonance imaging showed avascular necrosis of left femur head and so prednisolone was tapered and discontinued . thyroid hormone levels were normal [ table 1 ] . in 2009 , she experienced a sudden loss of weight ( 4 kg over 4 months ) . clinical examination revealed body mass index 18.59 kg / m , with grade i diffuse enlargement of thyroid gland and grade ii inactive orbitopathy . technetium 99 thyroid scintigraphy showed diffuse uptake of 6.8% ( normal 1 - 4% ) indicating graves ' disease ( gd ) [ figure 1 ] . technetium pertechnetate thyroid thyroid scintigraphy she was placed on carbimazole ( 20 mg daily as a single dose ) and propranolol ( 20 mg twice daily ) . she developed relapse of hyperthyroidism upon weaning carbimazole after 14 months , and total thyroidectomy was offered . she developed generalized body pain , asthenia and muscle weakness suggestive of myopathy and became wheel chair bound by 2012 . bone mineral densitometry studies of right wrist and lumbar spines showed t score of 3 and 2.7 , respectively . technetium mibi double phase parathyroid scintigraph after control of thyrotoxicosis , total thyroidectomy and subtotal parathyroidectomy retaining portion of right superior parathyroid gland were done . thyroid gland was diffusely enlarged with nodules in the right lobe and weighed 49 g. histology showed hyperplasic follicles lined by occasional tall follicular cells . the final histology showed features suggestive of gd of the thyroid gland and hyperplasia of parathyroid glands . the first case was reported in 1980 but later about 18 such cases were reported . however , boubakera et al . in a comprehensive review the present case demonstrated clinical features of hyperthyroidism with diffuse goiter and orbital involvement suggesting an autoimmune etiology . the clinical diagnosis of hyperthyroidism in esrd may be delayed due to overlap of symptoms . in suspected patients . the serum iodine level as well as intrathyroidal iodine content can be high in esrd patients and likely to exert transient or extended wolf - chaikoff phenomenon . the excess iodine may induce thyroiditis resulting in hypothyroidism . on the other hand , whether the excess iodine stimulates the gland to a hyperactive state ( jod - basedow effect ) is not clear . carbimazole was used in this patient after dialysis on those days since the drug could be washed off during the procedure . high dose of carbimazole was recommended since failure of conversion to active form is likely due to metabolic acidosis . surgical treatment was planned in this patient due to the presence of active orbitopathy and secondary hyperparathyroidism . all the more use of glucocorticoids was not advisable in case of deterioration of orbitopathy . Output:	thyroid hormone level may be altered in chronic renal failure patients . low levels of thyroxine protect the body from excess protein loss by minimizing catabolism . hyperthyroidism is rarely encountered in end - stage dialysis dependent patients . less than 10 well - documented cases of graves ' disease ( gd ) are reported in literature so far . we report a case of gd in a patient on dialysis .
PubmedSumm118865	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: a risk factor analysis has shown that patients with severe injury of the pancreas are significantly more prone to develop a candida infection . we describe a disseminated fungal infection as a complication of acute pancreatitis of the graft after simultaneous pancreas - kidney transplantation ( spkt ) . a 43-year - old caucasian male suffering from type 1 diabetes and chronic renal failure with peritoneal dialysis underwent spkt in december 2008 . the donor was a 26-year - old male ; the cross - match was negative . the transplant procedure was performed with no complications : the pancreas venous outflow was systemic via an end - to - side anastomosis between the portal vein of the graft and the recipient 's vena cava . the inflow was restored through an end - to - side anastomosis between the donor 's y iliac graft and the recipient 's common iliac axis . the kidney was transplanted intraperitoneally with arterial and venous anastomosis on the left external iliac axis . the cold and warm ischemia times were 355 and 510 minutes , 45 and 35 minutes for the pancreas and the kidney , respectively . eight days after transplantation the pancreas had to be removed because of the development of acute pancreatitis due to the thrombosis of the splenic artery of the graft . empirical antimicrobial therapy with piperacillin - tazobactam ( 2.2 grams x4/day i.v ) and fluconazole ( 400 mg / day i.v . ) was administered . a successful suture of the right external iliac artery was performed because of an acute rupture . histological examination of the artery evidenced fungal arteritis by candida glabrata ( c. glabrata ) with extended necrosis ( figures 1(a ) and 1(b ) ) , and culture yielded c. glabrata , with dose - dependent fluconazole and itraconazole sensitivity ( s - dd ) . antimycotic therapy with caspofungin ( 50 mg / day after a loading dose of 70 again , eight days later , the patient developed peritonitis and underwent another emergency operation ; a hartmann procedure was performed on the intraoperative finding of single perforation of the sigmoid colon . histological examination of the intestinal tract evidenced the presence of fungal spores and c. glabrata grew from culture of surgical specimens ( figures 2(a ) and 2(b ) ) , although the patient had already started antimycotic therapy with capsofungin ( effective on c. glabrata ) . the antimtycotic therapy , started 8 days before , was apparently insufficient to eradicate c. glabrata completely . on histological examination the surgical specimen revealed , besides fungal iphae , ischemic type lesions , probably responsible for perforation . the postoperative course was regular , the patient was switched from caspofungin ( total therapy 25 days ) to fluconazole ( 400 gm / die administered orally ) , and was discharged from hospital in good general conditions . candida is more likely to cause infection in patient having surgery for acute pancreatitis than in those with either gastrointestinal perforations or other surgical conditions [ 46 ] . in the transplantation field , arterial infection associated with candida some authors suggest that the infection is transmitted from the donor , with a potential source of infection represented by the contaminated graft , whereas the variability of the infectious risk is related to the duration and complexity of the harvesting and storage process . however , in our case no risk factors or positive fungal cultures were reported from the donor ; no signs or symptoms suggestive of systemic fungal infection were present in our case before transplant . the patient had a major risk factor for candida infection , represented by a history of peritoneal dialysis , but no episodes of peritonitis or other infections had been reported before transplant . moreover during the post transplant phase , no blood cultures were positive for candida spp . therefore , while the colonic localization of candida spp might be related to an endogenous source , the development of the arteritis is more difficult to explain without any episode of candidemia and graft contamination remains the more reasonable pathogenetic mechanism of infection . from a therapeutic point of view , it is worth remarking that invasive candidiasis developed despite fluconazole therapy ; although the isolation of an s - dd c. glabrata strain well explains the fluconazole failure . in literature , the incidence of gastrointestinal complications in renal transplantation is relatively high , about 20% . many predisposing factors have been suggested as steroids use , uremia and wound - healing capacity , chronic constipation , atherosclerotic change of the colon vascularization , and so forth , although the main causes reported are complication of a preexisting diverticular disease and intestinal ischemia [ 11 , 12 ] . in conclusion , this case points out that awareness and prevention of fungal infections are major issues in the transplant field . the best way for the early recognition of infectious risk remains the routine application of the colonization index screening , followed by preemptive antifungal therapy in case of positive results . Output:	fungal infections after kidney transplantation are a major cause of morbidity and mortality , and candida infection of the pancreas is considered an infrequent but important agent in necrotizing pancreatitis . we report the case of a 43-year - old caucasian patient who underwent simultaneous pancreas - kidney transplantation because of diabetes type i , and chronic renal failure with peritoneal dialysis . the postoperative course was complicated by acute pancreatitis due to the thrombosis of the splenic artery of the graft , the subsequent acute rupture of the external iliac artery caused by fungal arteritis ( candida glabrata ) , and peritonitis a few days later caused by sigmoid perforation with detection of candida glabrata infection of the resected intestinal tract . the present case remarks that awareness and prevention of fungal infection are major issues in the transplant field . important information can be added by systematic culture of conservation perfusates but , probably , the best way for early recognition of a critical level of infectious risk remains the routine application of the colonization index screening . in cases of positive results , preemptive antifungal therapy could be warranted .
PubmedSumm118866	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: reactive lymphoid hyperplasia ( rlh ) is characterized by the proliferation of a polymorphic lymphocytic infiltrate without an identifiable monoclonal subpopulation or other markers of malignancy.1 rlh is distinguished from orbital inflammatory syndrome clinically and histologically.2 rlh is a proliferation of lymphocytes within a structure as opposed to an inflammatory response . accordingly it usually presents more indolently with less pain , discomfort , and other inflammatory associates.2 traditional treatment modalities for rlh include corticosteroids and external beam radiation therapy ( ebrt).3 rituximab is a chimeric humanized monoclonal antibody directed against cd20 receptors , found on b lymphocytes.4 variably successful treatment of orbital rlh has been described with rituximab.57 in the largest series , 10 out of 11 patients ( 91% ) with orbital rlh refractory to steroids were reported to have responded favorably.5 disease recurrence was seen in six patients , between 4 and 70 months after initial treatment . in this manuscript , we present our experience with two patients with widespread multisystem rlh who presented with orbital involvement . he reported a 7 year history of steadily progressive bilateral painless proptosis and visual loss . he had a mild relative afferent pupillary defect on the right and mild optic disk pallor bilaterally . exophthalmometry measured 20 mm oculus dexter ( od ) and 17.5 mm oculus sinister ( os ) [ figure 1a ] . patient # 1 , pretreatment : ( a ) external photograph demonstrating bilateral proptosis ( b ) humphrey visual field demonstrating a superior arcuate defect and general constriction od ; normal field os ( c ) axial ( left ) and coronal ( right ) mri of the orbits demonstrating bilateral diffuse infiltration involving the extraocular muscles and lacrimal glands ( d ) pretreatment positron emission tomography ( pet ) demonstrating increased metabolic activity in the orbits ( left ) and paraspinal region ( right ) visual field testing was abnormal in the right and normal in the left eye [ figure 1b ] . [ figure 1c ] several extraorbital sites of involvement were detected on positron emission tomography ( pet ) . [ figure 1d ] biopsies of both the orbital and paraspinal masses were consistent with rlh . [ figure 2 ] patient # 1 : orbital biopsies demonstrating lymphoid hyperplasia ( a ) hematoxylin and eosin stain showing lymphoid follicles with well - formed germinal centers surrounded by mantle zones composed of a polymorphous mixture of small lymphocytes ( b ) cd20 immunohistochemical stain : cd20 positive b - cells are prominent in scattered follicles ( c ) cd21 immunohistochemical stain : highlighted dendritic cells underlie the follicles ( d ) cd3 immunohistochemical stain : t - cells are seen in both follicles and inter - follicular areas following failed treatment with steroids ( roughly 1 mg / kg for 1 month ) and doxycycline , two cycles of rituximab ( 370 mg / m weekly for 4 weeks ) were given . the visual field resolved with the exception of a slight depression od [ figure 3a ] . much improved but persistent abnormality was detected on mri . patient # 1 , post treatment : ( a ) humphrey visual field demonstrating a normal field os and near complete normalization od ( b ) mri demonstrating improved but persistent areas of abnormality ten months after the last rituximab treatment returned with periocular discomfort . exophthalmometry measurements had increased to 15 mm ou and progression of disease was seen on mri . following repeat rituximab therapy using a similar dosing regimen , the patient was again asymptomatic and remains so 11 months following treatment . a 66-year - old man was referred with a 3 month history of progressive proptosis [ figure 4a ] . he had bilateral blepharoptosis with a margin reflex distance ( mrd ) of 1 mm od and 3 mm os . multiple abnormal areas were also identified in the chest , most densely within the right hilum . [ figure 4c ] patient # 2 , pretreatment : ( a ) external photograph demonstrating bilateral proptosis ( b ) pretreatment axial ( left ) and coronal ( right ) orbital mri demonstrating bilateral infiltration involving the lacrimal glands ( c ) pet scan demonstrating increased metabolic activity of the right submandibular space ( left ) and at multiple focal areas in the chest ( right ) . multiple bilateral mediastinal foci are seen and likely represent lymph node involvement two cycles of rituximab ( 370 mg / m ) were given . the patient responded promptly with normalization of most findings : proptosis improved to 14 mm od and 13 mm os , supraduction returned to normal , and blepharoptosis improved with mrd of 2.5 od and 3.5 os . mri showed marked reduction in the soft tissue infiltrate of the lacrimal glands and extraocular muscles . mri demonstrated increased orbital infiltration and pet scan identified increased activity within the submandibular , hilar , and mediastinal lymph nodes . following repeat rituximab therapy , the patient was again asymptomatic and remains so 9 months following treatment . he reported a 7 year history of steadily progressive bilateral painless proptosis and visual loss . he had a mild relative afferent pupillary defect on the right and mild optic disk pallor bilaterally . exophthalmometry measured 20 mm oculus dexter ( od ) and 17.5 mm oculus sinister ( os ) [ figure 1a ] . patient # 1 , pretreatment : ( a ) external photograph demonstrating bilateral proptosis ( b ) humphrey visual field demonstrating a superior arcuate defect and general constriction od ; normal field os ( c ) axial ( left ) and coronal ( right ) mri of the orbits demonstrating bilateral diffuse infiltration involving the extraocular muscles and lacrimal glands ( d ) pretreatment positron emission tomography ( pet ) demonstrating increased metabolic activity in the orbits ( left ) and paraspinal region ( right ) visual field testing was abnormal in the right and normal in the left eye [ figure 1b ] . [ figure 1c ] several extraorbital sites of involvement were detected on positron emission tomography ( pet ) . [ figure 1d ] biopsies of both the orbital and paraspinal masses were consistent with rlh . [ figure 2 ] patient # 1 : orbital biopsies demonstrating lymphoid hyperplasia ( a ) hematoxylin and eosin stain showing lymphoid follicles with well - formed germinal centers surrounded by mantle zones composed of a polymorphous mixture of small lymphocytes ( b ) cd20 immunohistochemical stain : cd20 positive b - cells are prominent in scattered follicles ( c ) cd21 immunohistochemical stain : highlighted dendritic cells underlie the follicles ( d ) cd3 immunohistochemical stain : t - cells are seen in both follicles and inter - follicular areas following failed treatment with steroids ( roughly 1 mg / kg for 1 month ) and doxycycline , two cycles of rituximab ( 370 mg / m weekly for 4 weeks ) were given . the visual field resolved with the exception of a slight depression od [ figure 3a ] . much improved but persistent abnormality was detected on mri . patient # 1 , post treatment : ( a ) humphrey visual field demonstrating a normal field os and near complete normalization od ( b ) mri demonstrating improved but persistent areas of abnormality ten months after the last rituximab treatment returned with periocular discomfort . exophthalmometry measurements had increased to 15 mm ou and progression of disease was seen on mri . following repeat rituximab therapy using a similar dosing regimen , the patient was again asymptomatic and remains so 11 months following treatment . a 66-year - old man was referred with a 3 month history of progressive proptosis [ figure 4a ] . extraocular motility was full with the exception of limited supraduction ou . anterior and posterior segment examinations were unremarkable with the exception of early nuclear sclerosis . he had bilateral blepharoptosis with a margin reflex distance ( mrd ) of 1 mm od and 3 mm os . [ figure 4b ] pet scan demonstrated abnormalities in both orbits and the right submandibular area . multiple abnormal areas were also identified in the chest , most densely within the right hilum . [ figure 4c ] biopsies of the right orbital and submandibular masses were consistent with rlh . patient # 2 , pretreatment : ( a ) external photograph demonstrating bilateral proptosis ( b ) pretreatment axial ( left ) and coronal ( right ) orbital mri demonstrating bilateral infiltration involving the lacrimal glands ( c ) pet scan demonstrating increased metabolic activity of the right submandibular space ( left ) and at multiple focal areas in the chest ( right ) . multiple bilateral mediastinal foci are seen and likely represent lymph node involvement two cycles of rituximab ( 370 mg / m ) were given . the patient responded promptly with normalization of most findings : proptosis improved to 14 mm od and 13 mm os , supraduction returned to normal , and blepharoptosis improved with mrd of 2.5 od and 3.5 os . mri showed marked reduction in the soft tissue infiltrate of the lacrimal glands and extraocular muscles . mri demonstrated increased orbital infiltration and pet scan identified increased activity within the submandibular , hilar , and mediastinal lymph nodes . following repeat rituximab therapy , the patient was again asymptomatic and remains so 9 months following treatment . although variable success has been reported in the management of orbital rlh;57 this is the first report specifically addressing orbital involvement in widespread rlh . in this study we present two patients with systemic with orbital involvement . although clinical resolution was achieved with rituximab , in both patients , recurrent disease necessitated maintenance therapy . this recalcitrant disease emphasizes the limitations of rituximab therapy and could arguably be interpreted as failure . however , both of our patients responded to subsequent rituximab therapy and remain clinically asymptomatic years after presentation . until definitive treatment of widespread rlh is available , rituximab remains a viable option for such patients . Output:	rituximab , a monoclonal antibody to the b cell marker cd20 , is becoming increasingly popular in the treatment of various orbital disorders . in this university - based interventional case series , we describe two patients with bilateral orbital and extra - orbital reactive lymphoid hyperplasia ( rlh ) treated with rituximab . initially both had favorable responses ; but roughly a year later recurrent disease necessitated maintenance therapy in both cases . both again responded to additional courses of rituximab . although recalcitrant disease may persist after treatment , rituxmab may play a role in the management of rlh with widespread involvement .
PubmedSumm118867	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: aortic infection caused by aspergillus , including infection in immunocompromised hosts [ 18 ] and after cardiovascular surgery , , , , , , , is a rare event . aspergillus infection in immunocompromised hosts can occur in patients with hematologic disorders [ 15 ] , acquired immunodeficiency syndrome , or immunosuppression following kidney or heart transplant , . most patients with invasive aspergillosis have underlying hematologic neoplasms and neutropenia , and the duration and extent of neutropenia are significant risk factors for invasive aspergillosis . here , we present a particularly rare case of invasive aspergillosis in the aortic arch in a patient without hematologic neoplasms or neutropenia . a 79-year - old man who was a current smoker was admitted to our hospital for hemoptysis in july 2011 ( day 0 ) . before admission , pulmonary emphysema and multiple pulmonary bullae were detected on a chest computed tomography ( ct ) scan , and we also discovered that the patient had hypertension . he had a history of lobectomy of the left lower lobe for lung cancer in 1993 , with no recurrence ; two episodes of bacterial pneumonia ; gastrectomy for gastric cancer in august 2010 ; right spontaneous pneumothorax that required tube drainage in november 2010 ; and hospitalization for dyspnea in february 2011 , at which time chest radiographs showed left lung opacity and a chest ct scan showed consolidation with pleural effusion in the left lung . the lack of efficacy of bacterial antibiotics and the presence of multiple bullae and precipitating antibody to aspergillus in the serum ( day -163 ) led to a presumptive diagnosis of chronic necrotizing pulmonary aspergillosis . voriconazole with a loading dose of 800 mg a day followed by a maintenance dose of 400 mg a day was started on day -155 . a switch from intravenous to oral administration of voriconazole at a dose of 400 mg a day was made on day -106 . with administration of voriconazole , the opacity on chest radiographs had significantly improved by june 2011 . 1a ) showed consolidation in the upper field of the left lung and an infiltration shadow in the middle and lower fields of the left lung . serological human immunodeficiency virus ( hiv ) testing was not performed , but the patient had no obvious risk factors for hiv infection . the amount of expectorated blood decreased with rest , but massive hemoptysis occurred on day 16 . despite bronchial artery embolization , a macroscopic examination showed a hole in the aortic wall into the bullae ( fig . 2 ) . this hole was unlikely to have been a consequence of the autopsy procedure because a microscopic examination of the tissue around the hole showed extensive accumulation of inflammatory cells ( fig . this microscopic examination also revealed small fungal lesions in the pulmonary bullae adjacent to the aortic wall ( fig . the fungal hyphae were 5 - 10 m in width , with septae and a dichotomous pattern of branching at 45. these features are consistent with those of aspergillus species . microscopically , extensive necrotic lesions with aspergillus hyphae were found in the media of the aortic wall ( fig . immunohistochemical analysis with an anti - aspergillus antibody ( rabbit polyclonal antibody , anti - aspergillus antibody ab20419 ; abcam plc , cambridge , uk ) identified aspergillus hyphae in lesions in pulmonary bullae ( fig . 6a and b ) and in the necrotic media of the aortic wall ( fig . there was no other histopathologic evidence for aspergillosis elsewhere in the body , but we note that autopsy was not performed on the brain . there was no histopathological evidence for recurrence of gastric cancer , lung cancer , or bladder cancer . aortic infection by aspergillus has been described in patients with hematologic disorders , including mycotic aneurysm of the thoracic aorta , rupture of a sinus of valsalva aneurysm , occlusion of the aortic arch , a polypoid mass within the lumen of the descending aorta , and a mycotic sinus of valsalva pseudoaneurysm . in cases with a mycotic aneurysm of the thoracic aorta , occlusion of the aortic arch , and a polypoid mass within the lumen of the descending aorta , patients had neutropenia and developed pulmonary aspergillus infection , , and the pulmonary lesions invaded the aorta directly . in cases with a sinus of valsalva aneurysm or pseudoaneurysm , the preceding disease was aspergillus endocarditis or aspergillus pericarditis due to an immunocompromised state [ 2 , 6 ] . aortic infection has also been described after cardiovascular surgery for valvular replacement , , , aortocoronary bypass , , , and replacement of the aorta for aortic dissection . aspergillus aortitis includes ascending aortic pseudoaneurysm , aortic aspergilloma with supravalvular aortic stenosis , and fungal ascending aortic aneurysm . a histopathological study of aortic lesions in aspergillosis in immunologically compromised patients with hematological disorders showed formation of a mural thrombus in the intima , complete necrosis of smooth muscle cells in the media , and granulomatous chronic inflammatory change in the adventia . extensive necrotic lesions in the media of the aortic wall with aspergillus hyphae were also observed in our case . our patient had no hematological disorder and we did not detect any aspergillus lesions such as a fungus ball in a ct scan . the presence of infectious aspergillus lesions in pulmonary bullae and aortic infection by aspergillus became evident microscopically for the first time in the postmortem examination . aspergillus may have been inhaled into pulmonary bullae and colonized the bullae to produce more infectious lesions . we speculated that aspergillus in the lesions in pulmonary bullae had also invaded the aorta and made extensive necrotic lesions in the media of the aortic wall , including making a hole in the wall . this case was particularly unusual because the patient was immunocompetent and had neither hematologic disorder nor neutropenia . scedosporium apiospermum is a difficult fungus to differentiate from aspergillus in tissues and has been reported as a cause of mycotic aortic aneurysm in an immunocompromised patient . thus , without immunohistochemical evidence , fungal aortitis ( as observed in our case ) might be due to a non aspergillus spp . such as s. apiospermum . however , in our case , immunohistochemical results established the diagnosis of invasive aspergillosis in the aortic arch . although positive immunohistochemistry using an anti - aspergillus antiserum favors aspergillus spp . as causative agents , potential cross - reactivity of this serum can not be excluded . the observation that the pulmonary bullae were filled with blood at autopsy suggested that the source of bleeding in our case was the hole in the aortic wall , through which massive hemoptysis occurred due to the connection between the systemic circulation and the airway . a previous report has also described massive hemoptysis due to a thoracic aorta infected with aspergillus . however , a case with bleeding other than massive hemoptysis due to a hole in the descending aorta invaded by aspergillus fumigatus has also been described . our case with invasive aspergillosis in the aortic arch is particularly rare because most cases of aspergillosis in the aorta occur with accompanying hematologic neoplasms and neutropenia . Output:	a patient with pulmonary bullae died of massive hemoptysis . at autopsy a hole was observed in the aortic wall . a microscopic examination indicated small aspergillus lesions in pulmonary bullae and extensive necrotic lesions with aspergillus hyphae in the media of the thoracic aorta . these findings led to a diagnosis of invasive aspergillosis in the aortic arch . this is a rare case in which aspergillus invaded the aorta in a patient without hematologic neoplasms or neutropenia .
PubmedSumm118868	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: stimuli - responsive materials able to convert external stimuli reversibly to three - dimensional ( 3d ) mechanical motion have attracted significant attention for their potential to enable controllable and programmable shape morphing . great success has been achieved in utilizing stimuli - responsive materials for the self - assembly of 3d structures and the realization of shape - memory polymers . however , in many cases the self - assembled 3d structures are not designed to disassemble , and shape - memory polymers require a reprogramming cycle for repeated response . dynamically tunable materials capable of repeatedly and reversibly converting simple environmental stimuli into mechanical motion are of interest for developments in adaptable clothing , climate - responsive buildings , controlled encapsulation / delivery , solar tracking in photovoltaic farms , and the actuation of soft robotics . most living systems are capable of repeatedly responding to changes in their environment with a series of mechanical reconfigurations . the ability to fabricate synthetic materials that meet or exceed these capabilities is a substantial and significant engineering challenge . although some biological movements require complicated chemical and biological mechanisms , several plants demonstrate mechanoresponsive behaviors for seed dispersal that are deceptively simple and independent of cellular mechanisms . for example , an investigation into the mechanisms of unfolding / folding of pine cones and ice plants has revealed that they are based on a simple mechanism of differential swelling in response to variations in relative humidity . the simple change in humidity is able to create a complex mechanical response due to the controlled composition and structural attributes of the plant material . here a cellulosic inner layer organized in a stratified structure is capable of absorbing large amounts of water . paired with an opposing tissue that has a different cellulose fibril orientation that restricts the swelling behavior , a bending moment is generated . similar to the uniform heating of bimetallic strips , the difference in expansion coefficients does not allow for uniform expansion , and the internal stresses are equilibrated with a bending moment . the location of the bimorph within the plant creates a hinged structure where origami - like folding is realized . upon removal of the stimulus , the bimorph will return to its original shape , providing a straightforward way to create reversible and repeatable shape - morphing structures . reversible shape transformations from the differential swelling of synthetic bimorph structures in solution have been widely observed . differential swelling in hydrogel - based materials is a prominent example . in solution , their elastic networks allow for significant volume change based on polymer hydration and chain mobility . however , such a response to humidity outside of solution is difficult for solid synthetic networks where the increased stiffness imposes larger restrictions on chain mobility within the network , directly limiting responsiveness . the nanoscale structural control and versatility of layer - by - layer ( lbl ) assembly has been proven to be a simple technique for the fabrication of solid functional materials that respond to a variety of external stimuli . in most cases , these materials have been applied to trigger morphological changes on flat surfaces or to control the permeability of capsules within solution . surprisingly , little investigation into freestanding structures that can generate mechanical motion outside of solution has been performed . in addition to the fabrication of stimuli - responsive materials , lbl has also been employed to fabricate a wide variety of nanocomposites with very distinctive mechanical , electrical , biological , thermal , and optical properties . although traditionally a technique used to fabricate planar thin films , the introduction of multiscale and multidimensional patterning to create permanent shapes has been developed as an important step toward the incorporation of such materials into advanced functional devices . the next logical step is the incorporation of advanced stimuli - responsive functionality into such nanocomposite structures . herein we present lbl - assembled solid polymeric multilayers capable of driving shape transformations in response to environmental humidity and temperature variations . a hydrophilic polyelectrolyte multilayer is stacked with a less - responsive lbl - assembled carbon nanotube ( cnt ) composite . the differential swelling of the two lbl layers results in repeatable and reversible out - of - plane deformations . the sorption properties of polyelectrolyte multilayers are then revealed to drive a pseudonegative thermal expansion that is applied to drive similar shape morphing with temperature variations . in agreement with a theoretical model , the ability of lbl assembly to control thickness on the nanoscale allows for the responsive behavior of the material to be strictly controlled . lbl deposition by inkjet is employed to pattern the active material onto the base in order to localize the stresses for programmable folding . finally , a biomimetic structure is fabricated for the realization of a 3d responsive structure as inspired by the awn of wheat grass or tendrils of climbing plans . in a typical lbl cycle , glass slides cleaned by piranha solution for 24 h were immersed in 1% cationic polyurethane ( hepce chem co. , south korea , mw 92 000 ) for 5 min , rinsed with deionized water , and then dried with compressed air . subsequently , these slides were dipped into 0.25 mg / ml p3 single - walled carbon nanotube ( swnt , carbon solution inc . ) two hundred bilayer films were deposited on a glass substrate by a nanostrata robot . the ( pu / cnt)200 films were then removed with brief exposure to hydrofluoric acid . high - molecular - weight poly(diallyldimethylammonium ) chloride ( pdda ) and poly(sodium 4-styrenesulfonate ) ( pss , mw 70 000 ) were purchased from aldrich and diluted with deionized water . a ( pdda / pss)250 film was fabricated on a teflon substrate with 1 wt % solutions of each polyelectrolyte using the typical lbl cycle described above . upon removal from teflon , the films were stacked 4-fold before hot pressing under four tons at 80 c for 5 h to obtain a film thick enough to withstand characterization . the hot - pressed ( pdda / pss ) film and the ( pu / cnt)200 film were cut into 2-mm - wide and 15-mm - long strips for thermal mechanical analysis . the coefficient of thermal expansion , , of the film was measured in extension mode with a perkinelmer tma7 following the astm test method for the linear thermal expansion of solid materials by thermomechanical analysis ( e 831 ) and slightly modified to measure thin films . the extension probe and grips were customized by rt instruments , inc . to minimize the expansion of the grips during the measurement . ultrapure helium was used as a purge gas to give an inert atmosphere and facilitate heat transfer . cooling of the chamber was accomplished by circulating water at 8 c provided by a chiller . the tma instrument was calibrated using an aluminum standard ; the experimental error for of aluminum was 7.6% for temperatures as high as 300 c . the of kevlar fibers from dupont was also measured as an additional calibration for negative expansion , yielding a value of 4.58 ppm/c , which is in agreement with data reported elsewhere . the strips were stretched under 45 mn of force , and the length changes were recorded by monitoring the probe displacement for temperature ramps of 5 c / min . the sample was initially heated from 30 to 80 c and then stabilized for 2 h to remove free water and residual stress . the length change for both cooling and heating segments was used to calculate , represented by the slope of the curve normalized by the initial length at 30 c . for varied humidity testing , relative humidity values of approximately 7.7 , 2.5 , 1.4 , 0.7 , and 0.4% were achieved with a controlled flow of ultrapure 99.9995% helium . pdda and pss were diluted in deionized water to 0.025 wt % and sent through 0.22 m filters . two 10 pl droplet size cartridges with 16 piezoelectric nozzles were loaded separately with each polyelectrolyte . a fujifilm dimatix material printer ( dmp-2800 ) was used to deliver both polyelectrolytes to the surface with a typical voltage cycle ( waveform ) with two steps at a duration of 5.056 s each . first , a slew rate of 0.9 was applied to reach a level of 87% , followed by a slew rate of 0.19 decreasing to 0% . cartridge settings were set to a print height of 0.5 mm , a vacuum meniscus set point of 3.5 in . two overprints of each polyelectrolyte were alternately deposited to produce a ( pdda / pss)z film where z , the total number of repetitions of the 2 2 printing program , was varied between 4 and 10 . all samples were aligned and patterns were developed to print lengthwise as to allow for a brief drying moment between printed drops as the printer was repositioned along the y axis . patterns with lines in both the x and y directions were printed in two separate patterns with sample rotation in between to allow for all lines to be printed in this fashion . although the droplets are delivered at 5 m intervals , it is estimated that each droplet adds 50 m in width to the line . in the case of the multifold structure , ( pdda / pss)10 was printed in one direction before the sample was rotated , and ( pdda / pss)6 was printed orthogonally . after imaging , four additional layers were deposited so that both hinges had the thickness of ( pdda / pss)10 . in the case of the spiral , each hinge was made up of ( pdda / pss)10 . the hinges were patterned prior to cutting the spiral structure with a razor blade . for humidity - controlled investigation , a quartz chamber 1 in . 1 in . and 6 in . in height was fabricated to have two openings , one at the very top and one at 3 in nitrogen was switched on and off at 3 psi where it was allowed to flow into the top opening while the bottom opening remained open to ambient conditions . the chamber was placed on a small square of rubber to minimize leakage . in the case of temperature analysis , a 250 w heat lamp was set up at a distance of 15 cm above the sample . a small magnet was used to hold the sample in place to allow for imaging . temperature and ambient humidity were monitored with an hi 8064 hanna instruments hygrometer . several features of layer - by - layer ( lbl)-assembled polyelectrolyte multilayers ( pem ) make them attractive for solid stimuli - responsive materials that can drive reversible and repeatable shape morphing . first , during the lbl assembly of polyelectrolytes , the formation of polyanion polycation complexes provides an electrostatically cross - linked structure capable of holding water under ambient conditions . changes in environmental humidity drive the sorption and desorption of water , resulting in repeatable and reversable volumetric fluctuations . second , as a solid material with a young s modulus , e , around 1 gpa , lbl polyelectrolyte composites provide greater mechanical integrity than , for example , high - performing hydrogels with sub - mpa moduli . third , although the increased mechanical integrity of a solid limits the swellability , the nanoscale structural control of lbl assembly may provide the means to allow for optimal volumetric expansion to be realized . when exposed to the same change in relative humidity , polyelectrolyte films assembled by lbl experienced a greater change in film thickness as compared to complexes prepared by simply mixing the same polyelectrolytes together . fourth , the presence of nanoscale pores and the success of lbl - based humidity sensors suggest that such dimensional changes may be able to occur rather quickly , as would be desirable for stimuli - responsive structures . finally , lbl materials are prepared under ambient conditions with nanoscale control over thickness and can be deposited directly into specific patterns without additional processing . this provides the potential to develop unique patterns easily for the prescribed 2d to 3d transformation of many different materials , including lbl - assembled nanocomposites . to investigate the performance of lbl polyelectrolyte multilayers as stimuli - responsive materials capable of driving reversible and repeatable shape morphing , poly(diallyldimethlammonium ) chloride ( pdda ) and poly(sodium 4-styrenesulfonate ) were prepared in a bilayer structure with a less - responsive carbon nanotube ( cnt ) composite . the cnt composite was fabricated by the lbl deposition of 200 layers of cationic polyurethane ( pu ) and single - walled cnts . it was removed from its glass substrate , and a thin strip ( 15 mm 3 mm ) was removed to serve as the shape - morphing platform . inkjet lbl assembly , an lbl patterning approach that allows for the direct - writing and strictly additive patterning of lbl materials in an accelerated manner , was used to deposit the stimuli - responsive lbl polyelectrolytes selectively onto a cnt strip . in this case , 10 bilayers of ( pdda / pss ) were deposited in a line 300 m in width that perpendicularly traversed the entire width of the strip . the pem was deposited 3 mm into the 15 mm ( pu / cnt)200 strip , creating a short arm and a long arm separated by a small bilayer that will serve as a hinge to actuate the long arm of the cnt strip ( figure 1 ) . after deposition , there is no need for additional adhesives or processing because the same electrostatic forces used for their assembly also hold the two layers of the bimorph together . this adhesion will allow for the expansion / contraction of the stimuli - responsive lbl material to apply stress to the cnt layers below , resulting in out - of - plane deformation as the lowest stress configuration is achieved . in fact , before any introduction of controlled stimuli , the stress generated during fabrication as the inkjet deposited ( pdda / pss)10 layers dry on the ( pu / cnt)200 film is reflected in an initial deflection angle , , of 43.9 1.5 at an ambient humidity of 24% . here , is a measurement of the trajectory of the large cnt arm at 0.5 mm with respect to the plane of the short cnt arm . schematic of the ( pu / cnt)200 strip with inkjet - deposited ( pdda / pss)10 . when exposed to humidity and temperature stimuli , the bimorph responds by bending , creating an angle of deflection of in the longer arm . here , depends on the thickness ( h ) , stiffness ( e ) , and expansion coefficient ( ) of each layer , along with the total length of the bimorph ( l ) . the stimuli - responsive behavior of the hinged films was first investigated at constant temperature with variations in environmental humidity . the sample was placed in a quartz chamber , and the shorter arm of the hinged film was weighed down to allow for any out - of - plane actuation of the bilayer hinge to be realized in the long arm of the lbl nanocomposite . the weight was placed no closer than 0.5 mm to the bilayer hinge so as not to influence the location of the fold . a stream of nitrogen was introduced into the chamber to decrease the relative humidity and drive desorption of water from the internal structure of the film . after 5 min ( i.e , t = 5 min ) , the nitrogen exposure led to a greater volumetric contraction of the ( pdda / pss)10 layer as a result of the desiccation of water . the different extents of contraction in the two layers generates an internal stress that increases the deflection angle of the hinged bilayer to = 80.9 1.5 ( figure 2a ) . upon termination of the nitrogen stream , the ambient humid air diffuses into the chamber and hydrates the structure , initiating a decrease in . after 20 min ( t = 25 min ) , the nitrogen stream is reintroduced and the cycle is repeated a total of three times for the realization of repeatable and reversible actuation of the bilayer hinge ( figure 2 , movie s1 ) . ( a ) graphical and ( b ) image representations of the dependence of the angle of deflection , , of the hinged film over time , t. nitrogen was turned on at t = 0 , 25 , and 50 and turned off at t = 5 , 30 , and 55 . the introduction of nitrogen causes to increase , and the removal of nitrogen allows to return to a lowered position . note that whereas the hinged film recovers to = 49.0 1.5 consistently when exposed to the same conditions , the recovery time of 20 min is not sufficient for a full return to the observed immediately after fabrication . however , when allowed to equilibrate for 1 h , the film makes a completely reversible recovery to = 43 . a range of 9 1.5 as will be employed to investigate temperature - induced shape morphing below . next , we investigated the stimuli - responsive behavior of the hinged film in response to temperature , t. as compared to a humidity chamber , the tools used to manipulate temperature are much more transportable , readily available , and simple , allowing shape - morphing structures that respond to temperature to be highly versatile . although the response of lbl pems has been established for humidity variations , their reponse to temperature variations outside of solution has received little attention . a recent investigation of the thermal response of layered graphene oxide assemblies suggests that materials with nanoscale channels that respond fairly quickly to a decrease in environmental humidity may respond to temperature variations with a pseudonegative thermal expansion ( pnte ) . here the thermodynamically required decrease in relative humidity with an increase in temperature drives the desiccation of water and a corresponding decrease in dimension that overcomes the intrinsic positive thermal expansion of the material . the fairly quick response to humidity observed in figure 2a prompted us to investigate ( pdda / pss ) multilayers as a pnte material for the widespread application of lbl pems for temperature - induced shape morphing . the coefficient of thermal expansion , , of lbl pems was evaluated with a stack of four ( pdda / pss)250 films fabricated with traditional lbl techniques and hot pressed together . the sample was exposed to a temperature ramp of 5 c / min over a t of 30 to 80 c while the linear displacement was monitored with a thermal mechanical analyzer ( perkinelmer ) ( figure 3a ) . the lbl pem exhibits a pnte effect with a repeatable and reversible response to temperature that occurs almost immediately following the environmental change . at an ambient relative humidity of 24 1% , the apparent linear coefficient of thermal expansion of the lbl pem was calculated to be 1 = 368 9 ppm/c over the temperature increase from 35 to 75 c . the extreme extent of contraction can be realized in comparison to the lbl cnt composite , which displays an apparent of only 2 = 6.5 4 ppm/c at ambient humidity . ( a ) thermal mechanical analysis of stimuli - responsive lbl pem showing an apparent negative thermal expansion that reversibily and repeatedly responds . a less - drastic contraction occurs while heating with less available water vapor ( relative humidity ) . to investigate the role of water , a continuous flux of ultrapure helium was applied during thermal mechanical analysis to decrease the environmental humidity incrementally around the sample . as observed in the graphene oxide assemblies , the extent of contraction and apparent of the lbl polyelectrolyte multilayers became less extreme as the source of water vapor ( relative humidity ) was decreased ( figure 3b ) . also similar to the pnte graphene oxide assemblies , the lbl film shows a quicker dimensional response to heating as compared to cooling . because unequal water sorption and desorption rates have been predicted in other polyelectrolyte systems , it is likely that water is playing a significant role in this behavior . even at a relative humidity of 0.37% , the lowest possible humidity that we could obtain within the tma sample chamber , the lbl pem still displays a negative expansion coefficient of 5.3 2.7 ppm/c . although this seems inherently unexpected , previous investigation into the relationship between water content and the expansion of lbl pems suggests a complicated mechanism of water sorption where the volumetric expansion is greater than required for the volumetric displacement of the increased water content . the exaggerated volumetric contraction with increased temperature , along with the quick , reversible , and repeatable response ( figure 3a ) , makes the lbl pem an excellent candidate for the active material in a solid , stimuli - responsive bilayer that transforms its shape with temperature stimuli . to demonstrate the feasibility of temperature - based shape morphing with lbl pem , the same ( pdda / pss)10 and ( pu / cnt)200 hinged film actuated above was heated remotely from 20.5 to 37 c with a 250 w heat lamp . because the presence of the cnt composite aids in the efficient absorption of near - ir radiation , the hinged film responds within 5 s of exposure to the lamp , reaching an average peak of = 79.9 2 within 2 min ( figure 4a ) . the hinged film recovers completely after 18 min ( t = 20 ) , when the environmental temperature under the heat lamp returns to 20.5 c . subsequent cycles of actuation of the heat lamp show reversible and repeatable shape morphing ( figure 4 and movie s2 ) . the heat lamp set up provides a faster response than the humidity chamber ; however , some instability is realized from the convection currents generated as the surrounding air is heated . ( top ) graphical and ( bottom ) image representation of the dependence of the angle of deflection , , on temperature variations over time , t. the heat lamp was turned on at t = 0 , 20 , and 40 and turned off at t = 3 , 23 , and 43 . the out - of - plane deformation under ambient humidity is driven by the difference in expansion coefficients ( 1 = 368 9 ppm/c , 2 = 6.5 4 ppm/c ) over the temperature change delivered remotely from the heat lamp of t = 16.5 c . the greater contraction of the ( pdda / pss)10 layer generates a compression stress on the ( pu / cnt)200 layer of the bimorph hinge , which delivers an opposing tensile stress to the lbl pem . the material and structural properties of the components allow for the internal stresses within the bilayer hinge to balance through an out - of - plane deformation . originally derived by timoshenko , a force balance can be performed to estimate the radius of curvature , , of the bending moment . in the case where the bilayer is employed as a hinge , the unsecured arm can be assumed to follow a trajectory that is tangent to this curvature when in close proximity to the hinge . this tangent extends at an angle of displacement that is geometrically equivalent to the angle subtended by the curved bilayer . combining timoshenko s equation for with the geometric definition of arc length allows for the angle of displacement to be expressed in the following manner , where variables m and n are defined as the ratio of layer thickness , h1/h2 , and elastic moduli , e1/e2 , respectively . the theoretical model enables one to investigate and optimize how the angular deflection depends on the material and structural properties of each component . while assuming that n and the value of ( 2 1 ) remain constant over the temperature range explored , we can mathematically investigate how variations in the thickness of the pem layer influence ( figure 5 ) . from previous studies , e1 is assumed to be 1 gpa , and e2 and h2 were measured to be 1.8 gpa and 1.5 m , respectively . the thickness of the lbl pem , h1 , was varied while l was held constant at 300 m . here we see that nanoscale control over pem thickness can provide strict control over the morphology of the actuated structure . one of the many benefits of lbl assembly over alternative composite fabrication techniques is its nanoscale control over thickness . when the thickness of the pem layer is varied , the angle of deflection can be strictly controlled as expected by the theoretical analysis ( figure 5 ) . although the theoretical model assumes that the bilayer is uniformly heated / cooled , curvature is occurring only in one direction and neglects any shear or external forces . over the range of thicknesses explored , the model fits quite well . for larger temperature ranges , we expect to see larger deflections that eventually will plateau because the pem layer will be fully dehydrated . influence of the thickness , h1 , of the stimuli - responsive lbl pem layer on the change in deflection angle , , over t = 16.5 c . not only is inkjet lbl capable of controlling the thickness of the stimuli - responsive bilayer , but it can also be used to pattern stresses specifically into localized regions of the nanocomposite . an attractive but relatively unexplored area is the fabrication of reconfigurable or stimuli - responsive polymeric structures that can fold or unfold in specified patterns . although theoretical models exist for simple hinge - type structures , the introduction of additional and multidirectional hinges into one structure quickly complicates the balance of internal forces within the nanocomposite . figure 6a shows a square ( pu / cnt)200 strip with orthogonal prints of ( pdda / pss)z where z = 10 is printed in the vertical direction and only z = 6 is printed in the horizontal direction . upon exposure to the heat lamp , the structure folds in a manner where ( pdda / pss)10 dominates and only slight bending is realized across the ( pdda / pss)6 hinge ( figure 6b ) . additional stimuli - responsive material can then be added to make both hinges the same thickness ( pdda / pss)10 . as shown on the right , the folded structure of the film is completely different because both hinges provide approximately the same stress on the lbl nanocomposite ( figure 6c ) . such structures are of interest because of the numerous applications that can benefit from precise control over 3d actuation . of possible greater impact , the controllability provided by inkjet lbl opens the door for opportunities to investigate the fundamental mechanics of complex folding so that the development of prescribed 2d to 3d transformations can be widely applied . the vertical hinge is ( pdda / pss)10 , and the horizontal hinge is ( pdda / pss)6 . ( b ) upon exposure to heat , the structure folds into a structure where the thicker film dominates . ( c ) the same sample folds into a shape with equal curvature at the hinge with the addition of extra layers of pem to make both vertical and horizontal hinges the same thickness . this demonstrates control of the final shape based on the number of layers deposited at the hinge . in nature , an example of a structure that relies on actuation methods beyond that of a single hinged bimorph is the dispersion mechanisms of awns . select seeds of grass and wheat have long awns attached to them that aid in dispersing the seeds through a coil and uncoil motion driven by humidity . here the functionality of the awn is achieved through very subtle yet highly precise twisting movements based on the spatial arrangement of the cellulose fibrils . although traditional machinery can offer great strengths and frequencies , the ability to make subtle , gentle , and precise movements is often challenging . materials such as wheat awns serve as a source of inspiration for the design of adaptive and stimuli - responsive materials , with applications in soft robotics . to investigate the opportunity to create a nanocomposite material capable of a controlled and stimuli - responsive twisting motion , a spiral - like structure was prepared from the lbl nanocomposite , where pem hinges of ( pdda / pss)10 were specifically patterned onto the corners of the spiral as shown in figure 7a . when hung within the humidity chamber , the cnt spiral stretches out into a long coil . upon exposure to nitrogen , the structure responds in a very subtle yet predictable fashion . the stress generated by the bimorph hinges causes the structure to rotate just enough for the central panel to face a different direction before returning back to it is original direction when the nitrogen flow is discontinued ( figure 7b and movie s3 ) . because lbl serves as a universal approach to the fabrication of nanostructured materials , the simple addition of additional materials to make the structure responsive to multiple stimuli for alternative shape transformations ( a ) a spiral is cut into an lbl nanocomposite that has stimuli - responsive hinges inkjet printed into the edges of the spiral ( drawn in as dotted lines ) . ( b ) when hung from a support and introduced to nitrogen , the structure responds with reversible and subtle twisting motion . nature frequently produces solid materials capable of repeatedly and reversibly transforming shape in response to variations in environmental temperature and humidity . mimicking these motions achieved in nature in synthetic materials provides opportunities for inducing controllable motion into lbl nanocomposites . lbl pems provide stimuli - responsive swelling with changes in humidity that also allow for actuation based on temperature due to the pnte . when patterned with inkjet technology on a cnt nanocomposite , the two form a bimorph structure capable of controllable and reversible shape transformations with fairly advanced complexity . a number of challenges remain for both the theoretical and experimental front of shape - morphing structures . furthermore , integration with diverse materials is required to enable electronic , optical , and biomedical functionalities . widespread application will require further miniaturization and scaling of the self - folding mechanisms . in terms of theoretical challenges , further investigation into the mechanism of swelling , especially in the case of pnte , the application of lbl and inkjet technology , however , serves as a promising approach to addressing several of these challenges based on the high level of structural control granted with the combination of the two technologies . Output:	nature provides a vast array of solid materials that repeatedly and reversibly transform in shape in response to environmental variations . this property is essential , for example , for new energy - saving technologies , efficient collection of solar radiation , and thermal management . here we report a similar shape - morphing mechanism using differential swelling of hydrophilic polyelectrolyte multilayer inkjets deposited on an lbl carbon nanotube ( cnt ) composite . the out - of - plane deflection can be precisely controlled , as predicted by theoretical analysis . we also demonstrate a controlled and stimuli - responsive twisting motion on a spiral - shaped lbl nanocomposite . by mimicking the motions achieved in nature , this method offers new opportunities for the design and fabrication of functional stimuli - responsive shape - morphing nanoscale and microscale structures for a variety of applications .
PubmedSumm118869	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: there is an emerging concern about the shortage of child psychiatrists in canada and elsewhere [ 1 , 2 ] , a problem that is expected to worsen in the coming years . as availability of psychiatric expertise diminishes , access to timely and appropriate specialty mental health care for children and youth , the problem of access is particularly problematic in rural communities and complicates provision of mental health services . the ratio of child psychiatrists to children with mental health needs is approximately 1 : 6,148 . however , only 2% of child psychiatrists practice primarily in areas with populations of less than 20,000 , though approximately 18% of the population lives in rural areas . the shortage of resources and support services in rural communities means that children requiring urgent care often are frequently placed in residential care outside of their community . live interactive videoconferencing technology offers an innovative opportunity to address the shortage of child psychiatrists in canada . the use of interactive video technology is endorsed by the canadian academy of child psychiatry . also , the canadian standing senate committee on social affairs , science , and technology recommends that telepsychiatry be used in rural and remote communities for consultations , education , and training of mental health practitioners . in 1997 , the hospital for sick children ( sickkids ) , in toronto , ontario , undertook a pilot project to provide mental health support to primary care settings through videoconferencing . fully operational in 2000 , the program evolved to become the telelink mental health program . the program aims to enhance the knowledge , skill set , and confidence of children 's mental health practitioners using videoconferencing and other technologies by providing timely , equitable access to bilingual ( english and french ) specialist services . videoconferencing between recipient far sites and telelink hub site occurs by way of internet protocol ( ip ) , ( maximum bandwidth 384 kbits / second ) . two or more sites can be connected simultaneously , and videos , powerpoint , and scanned documents may be transmitted . the hub site is equipped with five stationary studios , each utilizing a 50 inch plasma or lcd monitor , and one mobile unit containing a 17 inch lcd monitor . both hub and far sites can be viewed simultaneously , and all cameras have local and remote pan - tilt - zoom control . infrastructure support is provided by core staff at the hub and a designated telepsychiatry coordinator at far sites . referral routes are multiple : 15 primary children 's mental health agencies in rural ontario ( including satellite locations ) ; three community hospitals ; one youth detention centre ; one community youth justice diversion program ; and community physicians . models of service delivery include clinical consultation and/or short - term follow - up , professional to professional consultation , shared care , program consultation , and education and training . as a consultative program , responsibility for the case remains primarily with the referring agency or physician , with the consulting psychiatrist neither accepting ongoing responsibility for primary care , nor prescribing medication . referring clinicians complete a mental health assessment before the consultation . supporting documentation such as past psychological / psychoeducational evaluations , school reports , and screening tools , is also requested . it is highly encouraged that the client 's primary clinician / case manager be present during the session ; other participants may include parents / caregivers and others involved in the child 's care . since its inception , the telelink mental health program has successfully recruited a stable core of consulting child psychiatrists . twenty - three child psychiatrists within the division of child and adolescent psychiatry at the university of toronto provide the bulk of services through a regular weekly or monthly roster , as determined by the consultant 's interest , availability , and commitment . an additional 16 faculty members are called on regularly for specific consultations and educational sessions , depending on their expertise and availability . the recruitment of child psychiatrists into the telelink mental health program has grown since its inception . however , little is known about the factors that may influence the decision of residents and child psychiatrists to work with rural and remote communities via televideo . in a child and youth mental health system that is fragmented , underfunded , and with a critical shortage of specialists in rural areas , it is important to identify the factors that could enhance recruitment into telepsychiatry and contribute to the expansion of telepsychiatry services to rural and remote communities . this study identifies aspects of psychiatry work that are most rewarding , as well as those that are challenging , from the perspective of psychiatrists and residents participating in televideo consultation services . to enhance our understanding of psychiatrists ' decisions to participate in the provision of services via televideo , this study used a mixed method design , combining quantitative and qualitative methods . for the quantitative component , a web - based survey was developed using surveygizmo online software . for the qualitative phase , in - depth interviews and a focus group the survey was distributed via e - mail to all child psychiatrists ( n = 80 ) within the division of child and adolescent psychiatry at the university of toronto . the distribution sample was based on the fact that the telelink program is well promoted within the division and all faculty members are eligible to participate in the program . the survey included questions related to their experiences with the telelink program ( see tables 15 ) . twenty - six responses ( 32.5% ) were received , a response rate exceeding expectations for web - based surveys ( 27.4% ) [ 9 , 10 ] . it was created by the authors based on their collective experience in the field , literature review , and consultation with key stakeholders . its design was informed by a social ecological framework that highlights the need to address phenomena from the interaction among many factors at the individual , relationship , community , and societal level . focus groups and semistructured individual interviews were conducted to provide a more detailed examination of the survey questions . invitations to participate in a focus group were sent to all division child and adolescent psychiatrists ( n = 80 ) and all psychiatry residents ( n = 26 ) located at the hospital for sick children at the time of data collection . despite multiple attempts to engage focus group participants , as such , one focus group was held with four psychiatry residents . for the individual interviews , eight individuals involved or familiar with pediatric telepsychiatry services were approached , both in ontario and internationally . six individuals agreed to participate ; four providing services to the telelink program in ontario and two providing services to programs outside the country , one in the united states and one in australia . this sampling strategy , focused on information - rich cases , was selected as most productive in helping us understand the factors that influence the decision to participate in a telepsychiatry program and those that may be unique to the telelink program . interviews lasted approximately 4060 minutes and were conducted either face - to - face or by telephone . a semistructured interview guide directed the interviews and focus group discussion ( see table 6 ) . as with the survey , the interview guide was informed by the authors ' previous work , the literature , and consultation with key informants . an open - ended text report assisted in the analysis of multiple choice questions as well as verbatim responses . the first step of the analytic process is bracketing , followed by construction and contextualization of findings . bracketing the process of construction classifies , orders , and reassembles the phenomenon back into a coherent whole . finally , with contextualization the 26 survey respondents consisted of 14 ( 53.8% ) males and 12 females ( 46.2% ) , ranging in age from under 34 to over 65 and averaging 47.1 years . there was a range of experience in working as a child psychiatrist , from 1 to 47 years , with a median of 21 years . over 80% of respondents ( n = 21 ) indicated that more than 50% of their practice was dedicated to working with children and adolescents . the type of services provided included outpatient ( 88% ) , consultation ( 80% ) , private practice ( 40% ) , in - patient ( 36% ) , and others ( 32% ) . survey respondents were all familiar with the telelink program but diverse in terms of their experience with the program . while more than one third indicated that they provide frequent consultation services of more than 12 per year ( 34.6% ) , there were respondents who had never provided services ( 23.1% ) ( table 1 ) . the majority ( 68% ) indicated that telepsychiatry is an important innovation that allows access to much needed resources in underserviced communities and that it is important for psychiatric trainees to develop expertise in providing consultation . to this end , 68% of respondents recommend that the university 's curriculum committee make telepsychiatry mandatory for subspecialty training . those who resist mandatory telepsychiatry training believe that people are more likely to choose it if it is not forced upon them . working with telelink technology was not identified as a significant barrier . as reported in tables 2 and 3 , respondents indicate that they are moderately ( 20% ) to very comfortable ( 60% ) conducting assessments via televideo ( with 72% selecting 7 or above on a 10-point likert scale ) , as well as with operating the video equipment and associated technology ( 40% and 56% , resp . ) . at least 50% of respondents identify a number of factors as being very important or important in their decision to provide psychiatric services via televideo , including the ability to provide services to underserviced communities , the support they receive from telelink administrative staff , contributing to the enhancement of rural provider capacity , and maintaining ongoing relationships with rural providers , financial incentives , and convenience ( table 4 ) . the novelty of the technology , privileges associated with a hospital appointment , and the opportunity to be a part of a larger group of professionals were of relatively lower importance . the management of the program , supporting telelink 's mission , working within a consultation model , trying out telepsychiatry on a trial basis and diversification of income sources were not identified at all as influencing the decision to become involved . survey respondents were asked to indicate the extent to which they agreed with a series of statements about the delivery of psychiatric services via televideo ( table 5 ) . the majority ( 76% ) agreed / strongly agreed that the technology was secure and confidential although about one - third ( 33.3% ) expressed concerns about safety and liability issues . more than half ( 56% ) desired more feedback about the helpfulness of the consultation . there was some need expressed for more knowledge about the particular culture of the community ( 20% ) and for more awareness of the specific resources available in rural communities ( 52% ) . respondents were asked to identify the circumstances that would allow them to provide more hours to the telelink program . responses included flexibility to see the child on more than one occasion , increased time for teaching and training , and review of documents , opportunity to work more closely with community physicians and to have their follow - up and support . for the qualitative phase of the study , participants were asked to discuss their involvement in a telepsychiatry program and the factors that may encourage or deter their participation . four main factors were identified : ( 1 ) organizational ; ( 2 ) shared values ; ( 3 ) innovation ; and ( 4 ) the consultation model . an important component in recruiting and retaining consulting psychiatrists is the support provided by the program 's executive and administrative staff . this result is supported in the survey data , with 96% of respondents identifying staff support as very important or important in their decision to participate in a telepsychiatry program . interview participants identified friendly staff , welcoming environment and comfortable set - up as influencing factors . consultants with the telelink program cited effective leadership by the telelink medical director , and his visibility within the department of psychiatry as important aspects of participation . psychiatrists noted that strong administrative and technical support ensures worry - free consultation sessions . as revealed in the survey data , the telelink program 's ability to provide a flexible work environment and willingness to adapt to consultant needs emerged as a deciding factor . in the qualitative interviews , further exploration revealed that prospective consultants , uncertain about participating , appreciated the offer of a trial period without obligation . further tailoring included flexibility regarding the number of hours worked per week or month and the type of cases offered . participants acknowledged that it takes time to become comfortable with televideo , and the option to try it out on a trial basis is a facilitator . for one international participant , the increasing demands on pediatric teaching hospitals and the psychiatry department make participation in telepsychiatry difficult to negotiate . while most consultants find participating in the telelink program convenient , those located at a distance from the program 's head office find it inconvenient and costly given commuting times and parking costs . one international participant notes that her institution schedules several televideo consultations in one day , similar to a half - day clinic , to make participation more attractive to consulting psychiatrists . ( 2 ) shared values . in keeping with survey respondents , interviewees indicate that a shared sense of purpose and belief in the mission of telepsychiatry is an important aspect of participation . involvement in telepsychiatry allows consultants the opportunity to improve access to mental health services in rural and remote communities and support local health practitioners . also in keeping with survey data , interview participants value the opportunity to enhance the knowledge and skills of rural clinicians , recognizing it as an innovative way to extend your skills beyond your local practice , and serve great benefits to rural communities . psychiatrists providing regular service to particular sites develop a strong connection and beneficial relationship with the rural clinicians and wider community . the sense of contributing to a shared mission and a collective pride in program accomplishments is attributed to the staff retention rates . the fact that a program is well supported within the psychiatry department and showcased nationally and internationally enhances its profile . one consultant with telelink stated that the synchronicity of purpose between the program and its consultants is the vital ingredient in recruiting dedicated child and adolescent psychiatrists . retention is not just about money , but rather creating an environment where an individual feels comfortable , recognized , contributory to the mission . the role of innovation and technological advances in bringing scarce psychiatric resources to underserved communities emerged as a key factor to both the quantitative and qualitative participants . while survey data suggests that only 12% of respondents identify novelty of the technology as important or very important in their decision to provide services via televideo , 96% reported the opportunity to provide services to rural communities as important / very important . in our individual interviews , participants explore this theme further , acknowledging the increasing use of electronic connections such as skype and facebook in modern culture , the appeal this has for younger generations , and its potential role in attracting medical students to the field of psychiatry . psychiatry residents in the focus group session concur , describing the delivery of mental health services via televideo as a creative way to deliver a scarce resource to communities in need . in both interview and focus group data , the telelink program is credited with offering psychiatric residents unique training opportunities ( each of the core child residents at the university of toronto must participate in two telepsychiatry consultations , during their six - month rotation ) . in particular , it is seen as addressing important learning gaps , including how to do a consultation , work collaboratively , and use televideo technology effectively . according to the psychiatric residents , participating in telepsychiatry sessions is rewarding , particularly if the consulting psychiatrist provides opportunities to participate on camera and ask questions . being outside of the camera 's view was difficult , awkward , and not as rewarding . according to one participant , this positive experience may be both interview and survey data reveal a high level of comfort with technology among consultants , with many stating little or no differences between video and face - to - face consultations . others identify the immediacy of the service as important , as well as the ability to follow - up with patients via video . while participants noted that the technology does not interfere with performing a mental health assessment , some difficulties were identified such as poor picture quality , audio lag , uncertainty in operating the equipment , and unstable internet connections in remote communities . also , one participant noted that room setup and camera placement at the far sites are not always ideal . despite these difficulties , one participant states that the advantages of telepsychiatry far outweigh these small disadvantages , while another dismisses them as a consultation model of service delivery was the fourth theme to emerge from the qualitative phase of research . though this theme was not selected by survey respondents as an important factor in their decision to work with telelink , 92% strongly agreed or agreed with the statement i am comfortable with the consultation model of service delivery and i am only given cases that match my area of expertise as important or very important to their participation . also , 80% identified telepsychiatry as a valuable resource to communities with limited access to specialized mental health care . in the interviews , psychiatrists indicate that the consultation model of service delivery encourages participation since the consulting psychiatrist does not accept ongoing responsibility for primary care , nor does he or she prescribe medication or do treatment . with a full - time job and regular patient load elsewhere , interview participants appreciate the opportunity to expand their practice without having to take on new patients . the financial incentives are attractive , as is the possibility to diversify their income sources . the majority of interview participants indicate that conducting psychiatric assessments via televideo does not significantly differ from those conducted face - to - face . one experienced psychiatrist , new to telepsychiatry , however , expresses a preference for face - to - face encounters and the need for more than one consultation session to do a thorough assessment . an added concern was the lack of feedback from rural clinicians regarding the effectiveness of his recommendations , stating i have no idea whether any of this is making any difference in kids ' lives because i have not seen any follow - up data . other concerns emerging from the qualitative data include the lack of information regarding resources in rural communities , rural clinicians who may be inexperienced due to high turnover rates , and having to tread carefully so as not be seen as a there was also a lack of knowledge regarding liability and safety issues , clinical follow - up procedures , and funding mechanisms , with one consultant stating what is the renumeration ? i do not know how i get paid ; i do not know what it is . many of these themes echo concerns expressed by survey respondents , as reported earlier . despite these concerns , study participants acknowledge that , by providing timely , equitable access to specialist services , the telelink program fills an important gap in the children 's mental health system , distributing ( psychiatric expertise ) to a wide area . the delivery of psychiatric services using videoconferencing technology is an efficient , cost - effective [ 1316 ] , and user - friendly approach that has been recommended for expansion in jurisdictions across canada . however , it has been noted that the growth and advancement of telepsychiatry programs may be constrained by human resource factors , including psychiatry workforce shortages [ 2 , 18 ] and resistance from specialists to participate in such programs [ 19 , 20 ] . as such , it is important to understand what factors may encourage or deter specialists from engaging with telepsychiatry programs . the telelink mental health program offers a compelling case as it has regular access to approximately 40 child psychiatrists and , since its inception in 2000 , retained much of its original workforce . the main factors contributing to this success as identified by study participants provide important strategies for the field in attracting and retaining child psychiatrists to a telepsychiatry program . for both survey and interview participants , features such as efficient administrative staff , convenient setup , flexible work hours , and financial compensation allowed consulting psychiatrists to deliver services with minimal workload . in the literature , time , money , and technical skills are identified as barriers to the uptake of telemedicine . this study and others [ 22 , 23 ] indicate that such barriers can be significantly reduced by providing dedicated administrative and technological support . also , adequate funding is critical , with 80% of survey participants identifying financial compensation as important or very important to their participation . for consultants working primarily in locations at a distance from the host site , costs associated with commuting could be mitigated by offering multiple consultations per visit , or offsite service provision , where feasible . a second set of factors linked to telepsychiatry participation is related to the technology itself . the majority of survey and interview participants reported being comfortable with the equipment and technology , as well as conducting assessments via televideo . however , results suggest that more could be done to improve technical aspects and provider comfort . as reported in a recent literature review , problems related to nonverbal communication and audiovisual quality are seen as drawbacks to telepsychiatry and that more needs to be done to improve infrastructure issues . also , training , ongoing technical support , and more user - friendly technology have been shown to facilitate acceptance . comfort levels could also be improved through better communication and information exchange , for example , providing consultants with information regarding available resources in local communities as well as postconsultation feedback regarding the appropriateness and usefulness of their recommendations . finally , providing potential recruits and new consultants with an orientation package would help promote the program and provide answers to common questions , such as remuneration schemes and security issues . a third factor in attracting consulting psychiatrists is active participation in postgraduate training ; since 2005 , all psychiatry residents at the university of toronto are required to participate in at least two telepsychiatry consultations with the telelink program . additionally , three- and six - month electives are offered to interested residents . this strategy is supported by survey respondents who believe that an organized effort is needed to introduce medical students and residents to specialized pediatric training early in their training , with 68% recommending that the university 's curriculum committee make telepsychiatry mandatory for subspecialty training . in focus group data , psychiatry residents indicated that the opportunity to actively participate in televideo consultations was exciting and strengthened their interest in this model of psychiatric work . these data align with research that suggests exposure to positive training opportunities , and participation in psychiatry electives may enhance recruitment into psychiatry . given the downward trend in psychiatric recruitment [ 2830 ] , it behooves telepsychiatry programs to work with medical schools and psychiatric recruitment officers . to this end , the canadian mental health commission has encouraged the inclusion of telemental health instruction in medical schools . this study aimed to gather objective data regarding how a telepsychiatry program in toronto , canada , is able to attract and keep child psychiatric consultants to the program , in the context of declining psychiatric recruitment and the difficulty in attracting psychiatrists to do this work , as indicated informally by similar programs in canada and elsewhere . these results help us understand what aspects of telepsychiatry are most likely to attract and retain psychiatry practitioners , as well as aspects most appreciated by consulting psychiatrists and residents . also , this study helps inform the effective recruitment of new graduates to the field , a current challenge for the telelink program . in response to this challenge , the university of toronto 's department of psychiatry has made adult telepsychiatry a key goal and has asked the telelink program to assist in setting up the program and attracting consulting psychiatrists . more research is needed to better understand residents ' experiences of participating in the telelink program , and more specifically what might attract them to continue to work in telepsychiatry after graduation . future research would include a multicentered study involving other telepsychiatry programs in ontario and across canada . this study offers important insights into addressing possible barriers in attracting psychiatrists and residents to a telepsychiatry program . it also provides an opportunity to think about wider recruitment and retention issues in the field of psychiatry . understanding what aspects of the telelink mental health program are most appreciated by consulting psychiatrists and what attracts residents to the program offers useful strategies to telepsychiatry administrators and medical school educators seeking to attract , train , and retain psychiatry practitioners . Output:	objective . identify aspects of psychiatry work that are rewarding , as well as those that are challenging , from the perspective of psychiatrists and residents participating in televideo consultation services . method . a web - based survey was distributed to psychiatrists within the division of child psychiatry at the university of toronto . also , semistructured interviews were conducted with six child psychiatrists providing services to a telepsychiatry program . finally , a focus group interview was held with four psychiatry residents . results . child psychiatrists are very comfortable conducting assessments via televideo . factors identified as being important in the decision to participate in telepsychiatry include assisting underserved communities , supportive administrative staff , enhanced rural provider capacity , financial incentives , and convenience . the study 's qualitative phase identified four themes in the decision to participate in telepsychiatry : ( 1 ) organizational , ( 2 ) shared values , ( 3 ) innovation , and ( 4 ) the consultation model . conclusion . the success of televideo consultation programs in attracting child psychiatrists to provide consultation services to underresourced communities makes an important contribution to psychiatric workforce shortages . understanding what aspects of telepsychiatry are most appreciated by consulting psychiatrists and residents offers useful strategies to telepsychiatry administrators and medical school educators seeking to attract , train , and retain psychiatry practitioners .
PubmedSumm118870	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: brain volume loss and increase in white matter lesions ( wml ) are common consequences of aging , and both are related to worse cognitive function and risk of dementia [ 36 ] . little is currently known about the genetic determinants of age - related brain volume loss or increase in wml or how genes may modify the effect of other environmental risk factors for these outcomes . certain genetic polymorphisms associated with a greater risk for neurodegenerative diseases such as alzheimer 's disease ( ad ) in later life are potential candidates . the apolipoprotein e ( apoe ) gene is the best - documented genetic risk factor for ad , with the 4 allele significantly increasing the risk for ad [ 810 ] and cognitive decline . the angiotensin converting enzyme ( ace ) gene is associated with ad [ 12 , 13 ] and wml . certain vitamin d receptor ( vdr ) gene polymorphisms have also been associated with increased risk of ad , cardiovascular disease , and diabetes [ 16 , 17 ] , and these , in turn , have been linked to wmls [ 18 , 19 ] . these genes are , therefore , strong candidates for evaluation of genetic determinants of brain volume loss and increased wml in living persons through the use of neuroimaging technology . furthermore , because it is hypothesized that exposure to certain external agents may induce upregulation of neurodegenerative disease - associated genes , it is appropriate to also examine the effect of these genes in the light of gene by environment interaction . specifically , well - known risk factors for neurodegenerative disease , including cardiovascular risk factors and occupational lead exposure , may modify the effect of certain genotypes on brain volume loss and wml . research has begun to evaluate relationships between genetic risk factors and structural differences in the human brain , the vast majority investigating apoe [ 2131 ] . however , there are a number of limitations to this body of work , including a reliance on cross - sectional data and extrapolation of differences in structure across persons in different age ranges to within - person change . many of these studies also involve small sample sizes , limiting power to detect differences , and some focus specifically on certain brain structures such as the hippocampus rather than structures across the whole brain . furthermore , there has been little examination of the effect of gene by environment interaction on structural brain changes . in this paper , we report on the associations between apoe , ace , and vdr foki genetic polymorphisms and longitudinal change in brain volumes and wml from a cohort of over 350 older men who participated in two structural mris an average of 5 years apart . additionally , because these genetic polymorphisms may not directly contribute to changes in brain structure , but rather may modify the effect of other risk factors ( i.e. , gene by environment interaction ) , we tested for interactions between these genes and cardiovascular risk factors as well as occupational lead exposure in determining changes in brain volumes and wml . as previously described [ 3234 ] , subjects were initially recruited during two study phases between 1994 and 2003 . in phase i ( 19947 ) , former employees of a chemical manufacturing plant in the eastern united states were identified and recruited . in phase ii ( 20013 ) , additional study participants were enrolled and the first mri data was acquired . in phase iii ( 20058 ) , subjects who completed the first mri were invited for a second mri . all phases of the study were reviewed and approved by the johns hopkins bloomberg school of public health committee on human research and written informed consent was obtained from all participants . the selection , recruitment , and enrollment of former lead workers and controls ( community - dwelling persons without occupational lead exposure ) have been previously reported [ 3 , 3235 ] . during phase ii , all participants were eligible for mri measurement , and first mris were completed on 589 of 979 ( 60% ) former lead workers and 67 of 131 ( 51% ) controls . during phase iii , a second mri was obtained from a total of 377 persons : 317 of 589 ( 54% ) former lead workers and 45 of 67 ( 67% ) controls . reasons for not obtaining a second mri are reported elsewhere . the analytic cohort herein includes the 309 former lead workers and 44 controls with two adequate mris ( n = 353 ; 8 former lead workers and 1 control had inadequate first mris ) . detailed data collection methods for the first two phases of the study have been previously described . the remaining description is confined to measures specifically used for the analysis presented herein . in phase iii , the subject interview was expanded to include a number of additional study variables [ 37 , 38 ] . health outcomes ( e.g. , diabetes and heart disease ) were ascertained by interview response to the question , has a doctor ever told you that you had ( each condition ) ? only yes responses were counted ; participants who answered possible were classified as negative for all outcomes in order to increase specificity of outcome classification . for educational attainment , information was obtained by interview on years of education , trade school , general educational development ( ged ) credential , and other educational certificates using previously published methods . tibia lead , an estimate of lifetime cumulative lead dose , was available from earlier phases of the study on all former lead workers and all but one control with two mris . for former lead workers , current tibia lead was back - extrapolated to peak tibia lead , the estimated level at the end of employment in the factory . the measurement of tibia lead and this extrapolation to peak tibia lead are described elsewhere . all serum assays were performed in the core laboratory of the general clinical research center ( johns hopkins bayview medical center ) . c - reactive protein was measured by enzyme - linked immunosorbent assay ( elisa ) using the american laboratory products company ( salem , nh ) kit , with a sample sensitivity of 0.5 ng / ml , an intrasample coefficient of variation ( cv ) of 6.33% and an intersample cv of 2.20% . the lipid profile was performed on a medical computer systems analyzer with a sample sensitivity of 0.80% , an intrasample cv of 3.08% and an intersample cv of 3.72% . apoegenotyping was completed using different methods in the different phases of the study as technology progressed . the method of hixson was used during phase i. in phase ii , dna was isolated using the flexigene dna kit ( qiagen , valencia , calif , usa ) , and genotyping was performed using published pcr conditions [ 40 , 41 ] . in phase iii , dna was isolated as for phase ii . for genotyping , for determination of the c to t substitution causing the arg112cys and arg158cys polymorphisms , we performed allelic discrimination using taqman probes as previously described with the following modifications : ( 1 ) instead of using the nested pcr approach for the arg112cys polymorphism , 1x genotyping master mix ( applied biosystems , foster city , calif , usa ) was used with 20 ng of genomic dna and processed according to the manufacturer 's recommended protocol , ( 2 ) the 1x genotyping master mix was also used for the apoe arg158cys polymorphism , and ( 3 ) plate reads were performed in the 7500 real time pcr system to capture fluorescence , and genotypes were determined by manual clustering ( applied biosystems 7500 software v1.2.3 ) . of the subjects with two mris , apoe genotyping was performed with the phase ii method in 39.9% of subjects and with the phase iii method in 58.5% of subjects ( the rest genotyped in phase i ) . genotyping was completed using different methods in the different phases of the study as technology progressed . the method of hixson was used during phase i. in phase ii , dna was isolated using the flexigene dna kit ( qiagen , valencia , calif , usa ) , and genotyping was performed using published pcr conditions [ 40 , 41 ] . in phase iii , dna was isolated as for phase ii . for genotyping , for determination of the c to t substitution causing the arg112cys and arg158cys polymorphisms , we performed allelic discrimination using taqman probes as previously described with the following modifications : ( 1 ) instead of using the nested pcr approach for the arg112cys polymorphism , 1x genotyping master mix ( applied biosystems , foster city , calif , usa ) was used with 20 ng of genomic dna and processed according to the manufacturer 's recommended protocol , ( 2 ) the 1x genotyping master mix was also used for the apoe arg158cys polymorphism , and ( 3 ) plate reads were performed in the 7500 real time pcr system to capture fluorescence , and genotypes were determined by manual clustering ( applied biosystems 7500 software v1.2.3 ) . of the subjects with two mris , apoe genotyping was performed with the phase ii method in 39.9% of subjects and with the phase iii method in 58.5% of subjects ( the rest genotyped in phase i ) . acewe used a published pcr method to determine the insertion / deletion polymorphism of the ace gene with the following modifications : annealing time of 30 seconds and the final concentrations : 0.4 mol / l primers , 1.5 mmol / l mgcl , 200 m / l dntps , and 0.5 u taq . gels were imaged and photographed with a fuji las 1000 system and analyzed with fuji multigauge version 3.0 software . we used a published pcr method to determine the insertion / deletion polymorphism of the ace gene with the following modifications : annealing time of 30 seconds and the final concentrations : 0.4 mol / l primers , 1.5 mmol / l mgcl , 200 m / l dntps , and 0.5 u taq . gels were imaged and photographed with a fuji las 1000 system and analyzed with fuji multigauge version 3.0 software . vdrgenomic dna was isolated as for a previous study from stored blood using the flexigene dna kit from qiagen ( valencia , ca ) . for determination of the t to c substitution causing the vdr 12022 polymorphism ( allowing identification of ff , ff , and ff genotypes ) , we performed allelic discrimination using taqman probes ( applied biosystems , foster city , calif , usa ) using previously published methods for single nucleotide polymorphisms . allelic discrimination assays , consisting of primers and allele - specific taqman mgb probes labeled with 6fam and vic , were designed with primer express 2.0 and custom - ordered from applied biosystems ( sequences of primers and probes available upon request ) . all reactions contained 1x assay mix , 1x taqman genotyping mastermix , and 20 ng dna in 25 microliters . cycling was performed in the applied biosystems 7500 real time pcr system with the following conditions : 95c for 10 minutes and 50 cycles of amplification at 95c for 15 seconds and 60c for 1 minute . genomic dna was isolated as for a previous study from stored blood using the flexigene dna kit from qiagen ( valencia , ca ) . for determination of the t to c substitution causing the vdr 12022 polymorphism ( allowing identification of ff , ff , and ff genotypes ) , we performed allelic discrimination using taqman probes ( applied biosystems , foster city , calif , usa ) using previously published methods for single nucleotide polymorphisms . allelic discrimination assays , consisting of primers and allele - specific taqman mgb probes labeled with 6fam and vic , were designed with primer express 2.0 and custom - ordered from applied biosystems ( sequences of primers and probes available upon request ) . all reactions contained 1x assay mix , 1x taqman genotyping mastermix , and 20 ng dna in 25 microliters . cycling was performed in the applied biosystems 7500 real time pcr system with the following conditions : 95c for 10 minutes and 50 cycles of amplification at 95c for 15 seconds and 60c for 1 minute . mri acquisitionfor the first mri , all subjects were imaged at the same location on the same general electric 1.5 t signa model as previously described . t1-weighted images were acquired using an spgr sequence ( te = 8 ms , tr = 21 ms , flip angle = 30 , fov = 24 cm ) . axial pd / t2 ( tr / te / te2 = 2,200/27/120 ) and flair ( tr / te / t1 = 8,000/100/2000 ) images were also acquired for wml grading . for the first mri , all subjects were imaged at the same location on the same general electric 1.5 t signa model as previously described . for the second mri , t1-weighted images were acquired using an spgr sequence ( te = 8 ms , tr = 21 ms , flip angle = 30 , fov = 24 cm ) . axial pd / t2 ( tr / te / te2 = 2,200/27/120 ) and flair ( tr / te / t1 = 8,000/100/2000 ) images were also acquired for wml grading . clinical mri review and assignment of wml grade scoresmris were reviewed to exclude urgent or emergent brain disease and subjects and their physicians were notified if present . mris were assigned a wml grade score by a trained neuroradiologist using the cardiovascular health study ( chs ) ten - point ( 0 to 9 ) scale [ 44 , 45 ] , as previously reported , which allowed for analysis of change in ratings . mris were reviewed to exclude urgent or emergent brain disease and subjects and their physicians were notified if present . mris were assigned a wml grade score by a trained neuroradiologist using the cardiovascular health study ( chs ) ten - point ( 0 to 9 ) scale [ 44 , 45 ] , as previously reported , which allowed for analysis of change in ratings . the methods to obtain regional and voxel - wise volumes , including skull stripping , segmentation , registration , and transformation to regional analysis of volumes examined in normalized space ( ravens ) , were completed using published methods [ 34 , 36 , 4650 ] . due to changes in scanner technology and pulse sequences , we employed specialized image analysis methods that minimized the discontinuity between the two scans . we used the classic algorithm , which employs a 4-dimensional segmentation framework in which the baseline and follow - up scans are considered jointly to minimize discrepancies between the two segmentations and better estimate longitudinal change . the purpose of the present analysis was to first determine if genotypes for three different candidate genes were associated with changes in brain volumes and wml and then evaluate whether the genes modified relations of cardiovascular factors and tibia lead with changes in brain volumes and wml . multiple linear regression was used to evaluate associations of the polymorphisms with change in brain volumes using both roi - based and voxel - wise approaches as well as change in chs scores ( wml ) . all regression models were adjusted for baseline age , duration of time between mris , control status ( i.e. , former lead worker versus control ) , height ( cm ) , and education and baseline roi volume for roi analysis or baseline chs score for the wml analysis . results were similar for models that did not include terms for baseline roi volume or chs score ( not presented ) . because lead is associated with smaller brain volumes , we first evaluated whether the association between genotypes and change in brain volumes or wml differed between former lead workers and population - based controls or , within former lead workers , the associations of genotypes with mri outcomes differed by peak tibia lead ( ptl ) level . there was no evidence that associations of interest differed by control status , so we proceeded with our main analyses using data from both lead workers and controls . furthermore , a separate analysis found no association between ptl and change in brain volumes . we incorporated the results of ptl by gene interactions in former lead workers into our analyses as described below . we modeled change in 20 previously selected roi volumes consistent with our prior published reports ( as listed in table 2 ) . for bilateral structures , the volume represented the sum of right and left structures to minimize multiplicity concerns , but analyses were also performed separately for change in left- and right - sided roi volumes ( data not reported ) . we did not formally adjust for multiple comparisons in the analysis , choosing instead to report unadjusted p values and the number of regressions . we first examined the relationship between each genotype and change in roi volumes ( core models ) . we then separately examined the relationships between cardiovascular risk factors ( hypertension ( htn ; yes versus no ) , cardiovascular disease ( cvd ; yes versus no ) , diabetes mellitus ( dm ; yes versus no ) , total cholesterol , high - density lipoprotein ( hdl ) , low - density lipoprotein ( ldl ) , and c - reactive protein ( crp ) ) and change in brain volumes . to evaluate effect modification by genotypes on relations of cardiovascular risk factors with change in volumes or wmls , we added a term for cardiovascular risk factors ( separately ) and a cross - product term for genotype risk factor to the core models . effect modification by genotypes on age relations were also examined in separate models with a cross - product term for genotype age at baseline . we then examined effect modification by genotype on the relationship of chs score at baseline , as well as change in chs score across visits , with change in roi volumes . finally , in former lead workers , we examined interactions of ptl and genotypes on change in roi volumes . the relationship between genotypes and change in voxel volumes was modeled controlling for the aforementioned covariates using multivariate permutation testing in the r statistical programming language ( http://www.cran.r-project.org/ ) . the spm5 package ( statistical parametric software , functional imaging laboratory , wellcome department of imaging neuroscience , university college london , 2003 ) was used to perform smoothing using a 3d isotropic gaussian filter and mricro to display results . statistical significance was evaluated using a permutation approach that controlled for confounding variables . the maximum cluster size and cluster peak above the threshold was used to define a conservative permutation distribution on cluster sizes and peaks that , when compared to the observed cluster sizes and peaks , controls for multiple comparisons . linear regression was used to model change in wml grade scores controlling for covariates and evaluating the same effect modification variables . as in the roi - based analysis , we examined the relationships between cardiovascular risk factors and change in wml , and then effect modification by genotype on relationships of cardiovascular risk factors with change in wml . effect modification by genotype on the relationship of age and change in wml was also examined . in former lead workers , we examined interactions of ptl and genotypes on change in wml . basic descriptive characteristics of the 353 subjects with two valid mris are presented elsewhere . in short , the mean ( sd ) age was 65.1 ( 7.9 ) years ( range : 4882 ) , 93% had a high school education , and 90% were white . seven subjects were missing ace genotyping , 6 subjects were missing ace and vdr genotyping , and 1 subject was missing data for ace , vdr , and apoe . with the exception of crp by apoe genotype and diabetes by vdr genotype , there were no differences in distributions of cardiovascular risk factors by genotype ( table 1 ) . there were no differences in apoe , ace , or vdr genotypes by control status ( data not shown ) . there were no differences in apoe or vdr genotypes by mri status ( i.e. , zero versus one versus two mris ; data not shown ) ; we did not perform ace genotyping on persons without two mris . controls had significantly lower mean ( sd ) levels of total cholesterol ( 182.0 ( 31.5 ) versus 200.9 ( 40.8 ) , p = 0.004 ) and ldl ( 97.5 ( 29.4 ) versus 114.5 ( 34.8 ) , p = 0.003 ) , and higher levels of crp ( 3.3 ( 3.8 ) versus 2.4 ( 2.5 ) , p = 0.04 ) than former lead workers . as presented elsewhere in more detail , the volumes of all rois except for occipital wm declined from the first to the second mri over an mean ( sd ) time of 5.0 ( 0.4 ) years , with a more substantial decline in gray ( 24.4 cm ) versus white ( 5.4 cm ) matter . on average , total brain volume declined an average of 30 cm . cardiovascular risk factors and wmlthere was little consistent evidence of a main effect of cardiovascular risk factors on change in roi volumes . however , higher hdl was associated with more decline in 5 roi volumes : total brain volume ( (se ) = 0.183(0.078 ) , p = 0.02 ) , total wm ( (se ) = 0.101 ( 0.047 ) , p = 0.03 ) , parietal wm ( (se ) = 0.038 ( 0.011 ) , p < 0.001 ) , cingulate gyrus ( (se ) = 0.009 ( 0.004 ) , p = 0.01 ) , and hippocampus ( (se ) = 0.004 ( 0.001 ) , p = 0.006 ) . more wml at baseline and change in wml were not associated with change in roi volume . there was little consistent evidence of a main effect of cardiovascular risk factors on change in roi volumes . however , higher hdl was associated with more decline in 5 roi volumes : total brain volume ( (se ) = 0.183(0.078 ) , p = 0.02 ) , total wm ( (se ) = 0.101 ( 0.047 ) , p = 0.03 ) , parietal wm ( (se ) = 0.038 ( 0.011 ) , p < 0.001 ) , cingulate gyrus ( (se ) = 0.009 ( 0.004 ) , p = 0.01 ) , and hippocampus ( (se ) = 0.004 ( 0.001 ) , p = 0.006 ) . more wml at baseline and change in wml were not associated with change in roi volume . apoethere were consistent associations of apoe genotype with change in roi volumes ( table 2 ) . results are only presented for the 3/4 and 4/4 genotypes combined , from a model that also included terms for 2/2 plus 2/3 and 2/4 ( with 3/3 as the reference group ) . the positive beta coefficients indicate less decline for those with the 3/4 or 4/4 genotypes ( e.g. , the tbv for persons with the 3/4 or 4/4 genotypes declined an average of 23 cm versus 31 cm for persons with the 3/3 genotype ( figure 1 ) ) . the differences in roi volume declines by apoe genotype were largest and most consistent for changes in white matter volumes . there were consistent associations of apoe genotype with change in roi volumes ( table 2 ) . results are only presented for the 3/4 and 4/4 genotypes combined , from a model that also included terms for 2/2 plus 2/3 and 2/4 ( with 3/3 as the reference group ) . the positive beta coefficients indicate less decline for those with the 3/4 or 4/4 genotypes ( e.g. , the tbv for persons with the 3/4 or 4/4 genotypes declined an average of 23 cm versus 31 cm for persons with the 3/3 genotype ( figure 1 ) ) . the differences in roi volume declines by apoe genotype were largest and most consistent for changes in white matter volumes . there was evidence that apoe genotype modified relations of age with change in roi volumes . persons who were older at baseline and had the 3/4 or 4/4 genotype experienced more decline in the following roi volumes : frontal wm ( (se ) = 0.207 ( 0.086 ) , p = 0.02 ) , parietal wm ( (se ) = 0.115 ( 0.048 ) , p = 0.02 ) , corpus callosum ( (se ) = 0.023 ( 0.007 ) , p = 0.001 ) , hippocampus ( (se ) = 0.013 ( 0.006 ) , p = 0.02 ) , and amygdala ( (se ) = 0.008 ( 0.003 ) , p = 0.02 ) ( frontal wm displayed in figure 2 . there were no consistent interactions between cardiovascular risk factors and genotype for change in any roi volume . we next evaluated whether relations among change in wml and change in roi volumes were modified by apoe genotype . in models that included terms for change in wml and a cross - product for apoe genotype change in wml persons who had apoe 3/4 or 4/4 genotype and an increase in wml experienced less decline in the following roi volumes ; total brain volume ( (se ) = 6.658 ( 2.402 ) , p = 0.006 ) , total wm ( (se ) = 3.727 ( 1.419 ) , p = 0.009 ) , frontal wm ( (se ) = 1.717 ( 0.611 ) , p = 0.005 ) , temporal wm ( (se ) = 0.806 ( 0.358 ) , p = 0.03 ) , parietal wm ( (se ) = 1.183 ( 0.341 ) , p = 0.001 ) , medial structures ( (se ) = 0.802 ( 0.304 ) , p = 0.009 ) , cingulate gyrus ( (se ) = 0.251 ( 0.116 ) , p = 0.03 ) , insula ( (se ) = 0.242 ( 0.081 ) , p = 0.003 ) , corpus callosum ( (se ) = 0.117 ( 0.052 ) , p = 0.03 ) , internal capsulate ( (se ) = 0.125 ( 0.048 ) , p = 0.01 ) , and hippocampus ( (se ) = 0.139 ( 0.040 ) , p = 0.001 ) ( see , e.g. , figure 3 ) . there was no evidence that ace genotype modified relations of age with change in roi volumes . there was evidence that ace genotype modified relations of hdl with change in roi volumes . persons with greater hdl who had the i / i genotype experienced less decline in the following rois : total brain volume ( (se ) = 0.533 ( 0.211 ) , p = 0.01 ) , total wm ( (se ) = 0.342 ( 0.127 ) , p = 0.007 ) , frontal wm ( (se ) = 0.131 ( 0.055 ) , p = 0.02 ) , parietal wm ( (se ) = 0.080 ( 0.030 ) , p = 0.009 ) , occipital wm ( (se ) = 0.034 ( 0.017 ) , p = 0.04 ) , and hippocampus ( (se ) = 0.007 ( 0.004 ) , p = 0.04 ) . there was no evidence that ace genotype modified relations of any other cardiovascular risk factors or wml scores with change in roi volumes . there was no evidence that ace genotype modified relations of age with change in roi volumes . there was evidence that ace genotype modified relations of hdl with change in roi volumes . persons with greater hdl who had the i / i genotype experienced less decline in the following rois : total brain volume ( (se ) = 0.533 ( 0.211 ) , p = 0.01 ) , total wm ( (se ) = 0.342 ( 0.127 ) , p = 0.007 ) , frontal wm ( (se ) = 0.131 ( 0.055 ) , p = 0.02 ) , parietal wm ( (se ) = 0.080 ( 0.030 ) , p = 0.009 ) , occipital wm ( (se ) = 0.034 ( 0.017 ) , p = 0.04 ) , and hippocampus ( (se ) = 0.007 ( 0.004 ) , p = 0.04 ) . there was no evidence that ace genotype modified relations of any other cardiovascular risk factors or wml scores with change in roi volumes . there was no evidence that vdr genotype modified relations of age with change in roi volumes . there was evidence that vdr genotype modified relations of diabetes with change in roi volumes . persons who had diabetes and were heterozygous for the vdr foki ff genotype experienced less decline in the following rois : total wm ( (se ) = 9.873 ( 4.102 ) , p = 0.02 ) , frontal wm ( (se ) = 3.557 ( 1.755 ) , p = 0.04 ) , temporal wm ( (se ) = 2.412 ( 1.013 ) , p = 0.02 ) , occipital wm ( (se ) = 1.281 ( 0.537 ) , p = 0.02 ) , internal capsule ( (se ) = 0.336 ( 0.137 ) , p = 0.02 ) , and entorhinal cortex ( (se ) = 0.153 ( 0.062 ) , p = 0.01 ) . there was no consistent evidence that vdr genotype modified relations of any other cardiovascular risk factors with change in roi volumes . there was evidence that vdr modified relations of change in wml scores and change in roi volumes . persons who were homozygous for the vdr foki ff genotype and had an increase in wml experienced more decline in the following roi volumes : total gm ( (se ) = 4,570 ( 2.089 ) , p = 0.03 ) , frontal gm ( (se ) = 1.402 ( 0.604 ) , p = 0.02 ) , and parietal gm ( (se ) = 0.696 ( 0.319 ) , p = 0.03 ) , but less decline in two rois : frontal wm ( (se ) = 1.513 ( 0.723 ) , p = 0.04 ) , and parietal wm ( (se ) = 0.895 ( 0.401 ) , p = 0.03 ) . there was no evidence that vdr genotype modified relations of age with change in roi volumes . there was evidence that vdr genotype modified relations of diabetes with change in roi volumes . persons who had diabetes and were heterozygous for the vdr foki ff genotype experienced less decline in the following rois : total wm ( (se ) = 9.873 ( 4.102 ) , p = 0.02 ) , frontal wm ( (se ) = 3.557 ( 1.755 ) , p = 0.04 ) , temporal wm ( (se ) = 2.412 ( 1.013 ) , p = 0.02 ) , occipital wm ( (se ) = 1.281 ( 0.537 ) , p = 0.02 ) , internal capsule ( (se ) = 0.336 ( 0.137 ) , p = 0.02 ) , and entorhinal cortex ( (se ) = 0.153 ( 0.062 ) , p = 0.01 ) . there was no consistent evidence that vdr genotype modified relations of any other cardiovascular risk factors with change in roi volumes . there was evidence that vdr modified relations of change in wml scores and change in roi volumes . persons who were homozygous for the vdr foki ff genotype and had an increase in wml experienced more decline in the following roi volumes : total gm ( (se ) = 4,570 ( 2.089 ) , p = 0.03 ) , frontal gm ( (se ) = 1.402 ( 0.604 ) , p = 0.02 ) , and parietal gm ( (se ) = 0.696 ( 0.319 ) , p = 0.03 ) , but less decline in two rois : frontal wm ( (se ) = 1.513 ( 0.723 ) , p = 0.04 ) , and parietal wm ( (se ) = 0.895 ( 0.401 ) , p = 0.03 ) . lead by gene interactionin former lead workers , there was little evidence that ptl modified the relationship of candidate genes with change in roi volumes . a significant interaction of ptl with apoe 3/4 or 4/4 genotype was found in only one roi , occipital gm ( (se ) = 0.031 ( 0.016 ) , p = 0.045 ) . in former lead workers , there was little evidence that ptl modified the relationship of candidate genes with change in roi volumes . a significant interaction of ptl with apoe 3/4 or 4/4 genotype was found in only one roi , occipital gm ( (se ) = 0.031 ( 0.016 ) , p = 0.045 ) . change in voxel volumesin a parallel analysis , the supra - threshold clusters for the association of ace genotype and vdr genotype with change in gm and wm volume were within the range expected by chance ( not shown ) . the adjusted association between apoe 3/4 or 4/4 genotype and change in voxel volumes identified large supra - threshold clusters in wm , whose sizes were above the distribution of the maximum cluster size under the null hypothesis ( largest association cluster depicted in figure 4 ) . in a parallel analysis , results were substantively similar using a voxel - wise approach . the supra - threshold clusters for the association of ace genotype and vdr genotype with change in gm and wm volume were within the range expected by chance ( not shown ) . the adjusted association between apoe 3/4 or 4/4 genotype and change in voxel volumes identified large supra - threshold clusters in wm , whose sizes were above the distribution of the maximum cluster size under the null hypothesis ( largest association cluster depicted in figure 4 ) . summary statistics for change in chs wml scores between the first and second mri have been previously reported . in brief the apoe and ace genotypes were not associated with changes in wml scores . in adjusted analysis , controlling for age , duration between mris , control status , height , education , and baseline chs score , the vdr foki polymorphism was associated with increases in wml in a gene - dose - dependent fashion , with beta coefficients ( se , p - value ) of 0.18 ( 0.12 , p = 0.13 ) and 0.45 ( 0.16 , p = 0.006 ) for ff and ff genotypes , respectively . this indicates , for example , that , on average , subjects with the ff genotype had chs scores that increased 0.45 categories higher than did those with the ff genotype ( figure 5 ) . in former lead workers , there was no evidence of interactions of genes with ptl . in this cohort of nondemented older men with two mri scans an average of five years apart , we examined relations of three genetic polymorphisms with longitudinal change in brain volumes and wmls , our main findings were that the apoe 3/4 and 4/4 genotypes were associated with less decline in brain volumes over time , especially in wm , and that these genotypes modified the relationship of age as well as change in wml with change in brain volumes . we also found that the vdr foki ff genotype was associated with an increase in wmls . there was some evidence that the genotypes modified relations of cardiovascular risk factors with change in both roi volumes and wmls , but these findings were not consistent across brain regions or consistent across risk factors . there was no evidence that genotypes modified relations of lead levels with change in roi volumes and wmls in former lead workers . these findings give us some insight into the genetic determinants of structural changes in the brain that may contribute to cognitive impairments in later life . the 4 allele has been associated with smaller total brain , gray matter , hippocampus , amygdala , and corpus callosum volumes , and more wmls [ 2124 ] . however , there are a number of studies that have found no association between apoe and brain volumes [ 25 , 26 ] or wml in healthy samples , and at least three studies in ad patients have found an association between 4 and larger volumes [ 2729 ] . the majority of these studies used cross - sectional study designs in which change in structure volumes across age ranges is extrapolated from inter - individual differences in age . very little research has focused on how these genetic risk factors relate to longitudinal intraindividual changes in brain structure . in nondemented cohorts , one longitudinal study found an association of the 4 allele with greater hippocampus volume loss , while another found a nonsignificant trend for a relation between the 4 allele and greater brain atrophy . one longitudinal study on apoe genotype and wmls has been conducted , which found an increase in wmls in 4/4 individuals only . there has been little published research on ace polymorphisms and differences in brain structure . one study found an association between the i / i genotype and smaller hippocampus and amygdala volumes in women only , but no association with wml and another found no relation to volume or wml . a recent review found evidence of association between ace i / d polymorphism and wml from 9 cross - sectional studies , but cautioned against publication bias . our results are not consistent with the small number of studies that have previously examined the relations between the apoe 4 allele and change in brain volumes in nondemented cohorts . we found that subjects with the 4 allele had less rather than more decline in volumes of brain structures compared to those without the allele . this finding is unexpected in light of the established relation between the 4 allele and neurodegenerative diseases such as ad and the concomitant brain atrophy experienced by individuals who have these diseases . however , given the paucity of evidence regarding this relationship , these findings should be treated as preliminary and may suggest a different pathway from gene to ad expression as mediated through structural changes in the brain than have been previously recognized . for example , the association between 4 and less decline in volume was strongest in wm ; this could be consistent with an adverse effect in persons with the 4 allele if the slower rate of wm volume loss is due to inflammation , edema , swelling of cells , or other changes in wm that are present in early lesions in these relatively young study subjects . this hypothesis may be supported by the accompanying finding that higher levels hdl , usually considered protective against vascular events , was associated with more wm decline as well . alternatively , these findings may align with the emerging theory of apoe antagonistic pleiotropy in which the 4 allele confers an advantage at younger ages while producing detrimental neurocognitive consequences in later life . this is supported by our finding of an interaction between age and 4 status on wm decline in which persons with 3/4 or 4/4 genotype experience less decline than 3/3 carriers at earlier ages , but this difference attenuates and actually reverses after the age of 70 , after which 3/4 or 4/4 experience more decline . further , there is evidence that apoe antagonistic pleiotropy is related to integrity of the cholinergic system ; the most robust associations between 3/4 or 4/4 genotype and less decline was found in the basal forebrain ( figure 4 ) , a region considered to be the major cholinergic output of the brain . we also observed effect modification by apoe genotype on the relation of change in wml with change in brain volumes . persons with 3/4 or 4/4 genotypes experience more decline in brain volumes with increases in wml . notably , cardiovascular risk factors were not associated with increased wml , perhaps indicating that both decline in wm and progression of wml may not have linear relationships with traditional risk factors for cognitive impairment over the life course . finally , our study is the first to report on an association between vdr foki genotype and change in wml . this finding needs to be replicated before any conclusions can be drawn , but connections between vdr , cardiovascular disease , and wmls gives this finding biological plausibility [ 16 , 19 ] . the study had several strengths , including larger sample size than most prior studies , longitudinal design , use of roi - based and voxel - wise analyses , relatively long duration between scans , and analysis of wmls as determined by application of the chs wml grading method . the main strength of this study was the ability to examine intraindividual change in brain structures over a 5-year period using longitudinal data . this provides a more valid measure of change and predictors of change than extrapolating an estimate of change from separate individuals across a range of ages using cross - sectional data . a limitation of this study is the selected nature of the cohort , which was made up entirely of men , most of whom had histories of occupational lead exposure . however , general population samples have shown tibia lead levels similar to this cohort [ 60 , 61 ] , consistent with documentation that all americans over the age of 50 years had significant environmental lead exposure . thus , our ability to adjust for and examine interactions with lead is also a strength of this study . the fact that prior studies of older americans have not considered this ubiquitous neurotoxicant that influences brain volumes could be an important source of confounding . the ubiquity of lead exposure could also mask a potential gene by lead interaction , resulting in a gene appearing to exert a main effect . however , a gene by lead interaction was not observed for change in brain volumes or increase in wml . an important consideration that could affect the internal validity of these results is selection bias , as persons who had an mri scan in previous papers , we reported that there was unlikely to be meaningful selection bias , and if present , would likely mask rather than spuriously create associations [ 34 , 36 ] . we attempted to minimize the problems introduced by these changes by using an image analysis technique that was specifically developed and validated for longitudinal studies that is more likely to underestimate rather than overestimate longitudinal brain changes . in conclusion , this analysis adds to the emerging body of literature on genetic contributions to brain changes in later life . the findings suggest that early wm lesions in middle - aged persons with the apoe 4 allele may initially be space - occupying , due to inflammation , edema , or swelling of cells , but that with advancing age and increases in wm lesions , persons with the 4 allele experience more volume loss . this analysis is also one of the first to show an association between vdr genotype and changes in wm lesions . Output:	this study examined associations between polymorphisms in three genes , apolipoprotein e ( apoe ) , angiotensin converting enzyme ( ace ) , and vitamin d receptor ( vdr ) , and longitudinal change in brain volumes and white matter lesions ( wml ) as well as effect modification by cardiovascular factors and tibia lead concentrations . two mris , an average of 5 years apart , were obtained for 317 former organolead workers and 45 population - based controls . both regions - of - interest and voxel - wise analyses were conducted . apoe 3/4 and 4/4 genotypes were associated with less decline in white matter volumes . there was some evidence of interaction between genetic polymorphisms and cardiovascular risk factors ( ace and high - density lipoprotein ; vdr and diabetes ) on brain volume decline . the vdr foki ff genotype was associated with an increase in wml ( no association for apoe or ace ) . this study expands our understanding of how genetic precursors of dementia and cardiovascular diseases are related to changes in brain structure .
PubmedSumm118871	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: in 2014 , more than 32 000 women in the usa are estimated to be diagnosed with melanoma , with more than 3000 women dying from melanoma . moreover , nearly one - third of women diagnosed with melanoma are of childbearing age and 8% of malignancies are diagnosed during pregnancy . the treatment of melanoma in pregnant patients remains difficult and controversial as there are obvious concerns for the fetus , which include administering contrast agents , general anesthesia and as well as the stress of a major operation . although open inguinal lymphadenectomy has historically been the standard treatment for metastatic melanoma in the inguinal lymph node basin , multiple studies have reported significant morbidity following the procedure , with wound complication rates of 50% or higher [ 35 ] . videoscopic inguinal lymphadenectomy ( vil ) is a minimally invasive alternative that reports fewer wound complications , shorter hospital length of stay and a similar lymph node yield . this case report further illustrates the safety of vil as it is successfully performed in an expectant mother of 24 weeks . in june 2013 , a 38-year - old woman underwent wide local excision of her right thigh 1.4 mm thick melanoma with a negative sentinel lymph node biopsy ( slnbx ) . one year later and now 20 weeks pregnant , the patient was referred to our clinic with a palpable mass in the slnbx basin . preoperative imaging included computed tomography of the chest and magnetic resonance imaging of the abdomen and pelvis . these studies revealed post - biopsy changes in the right groin without involvement of the deep lymph nodes or other sites of concern . both video - assisted and standard open superficial groin dissections were discussed with the patient , as well as the risks and benefits of undergoing surgery during pregnancy . after conferring with our melanoma multidisciplinary clinic and obtaining approval from anesthesia and maternal fetal medicine , the patient and our team agreed to proceed with vil . at the time of her she was positioned supine on a split - leg table with a bump under her right hip to offload the inferior vena cava from the uterus . the femoral triangle boundaries were mapped out with a surgical pen , and the area was prepped and draped in a sterile fashion . a skin incision was made 10 cm inferior to the femoral triangle apex to accommodate a 10-mm balloon trocar . carbon dioxide ( co2 ) insufflation was started at 20 mmhg for the first 15 min and then lowered to 12 mmhg for the duration of the case . end - tidal co2 never reached above 35 mmhg during the case per anesthesia . under direct visualization using a zero - degree laparoscope , two 10 mm trocars were placed outside the medial and lateral boundaries of the demarcated femoral triangle . we identified the medial and lateral boundaries of the dissection to include the adductor longus and the sartorius muscle fascia . starting at the apex of the femoral triangle , dissection above the deep fascia of the thigh was advanced superiorly to the level of the inguinal ligament with identification of key structures , including the femoral vein and artery . the lymph node packet was removed from our working space and a 19-fr blake drain was introduced through the anterolateral 10-mm port and secured to the skin . both 3 - 0 vicryl and 4 - 0 monocryl sutures were used to approximate the dermal and skin edges . the patient was awakened from anesthesia and transported to the obstetrics recovery unit where fetal heart tones were monitored and a viable fetus was confirmed . her wounds healed well with no complications and the drain was removed 6 weeks after surgery . common complications include seromas , flap necrosis , wound infections and lymphedema . using vil , previous studies have demonstrated both equal and improved lymph node retrieval with decreased morbidity [ 6 , 7 ] . avoiding wound - related complications not only improves recovery time , but also decreases hospital readmission rates and need for postoperative antibiotics . this is most likely due to the fact that since the wounds do not breakdown , the drains continue to work instead of draining by way of an open wound and requirements for a wound vac . an additional potential concern is the retention of co2 during the case secondary to subcutaneous induced emphysematous changes of the dissection . while this remains a real concern , it has not yet required us to abort vil to convert to an open approach . this case demonstrates a safe approach to melanoma management without delaying treatment for an aggressive malignancy in the delicate setting of pregnancy . using this approach , we were able to harvest adequate nodes to fully workup a patient who has had multiple melanomas despite presentation in her second trimester of pregnancy . working in a multidisciplinary setting with inclusion of radiologists , oncologists , surgeons , maternal fetal medicine and anesthesia was essential to easily and safely facilitating the patient 's plan of care . while further research is clearly needed , our case demonstrates that vil can be a safe and effective option for inguinal node harvest for melanoma in the previously excluded population of pregnant women . Output:	lymphadenectomy is the standard of care for metastatic melanoma in the inguinal lymph node basin . historically , open surgery was the only treatment option . however , in recent years , videoscopic inguinal lymphadenectomy ( vil ) has become a popular approach as it offers a minimally invasive alternative , provides similar oncologic control and reduces wound complications . even though the vil approach is being used more frequently , the patient populations that stand to benefit the most from this approach are still under investigation . despite continued advances in safety for laparoscopic surgery , many surgeons are hesitant to perform these procedures on pregnant women . in this report , we present a successful vil in a pregnant patient , describe our technique and demonstrate the safety of performing vil in expectant mothers . to our knowledge , this case represents the first vil performed in an expectant mother .
PubmedSumm118872	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: trunk stability is essential for maintaining antigravity postures such as sitting and standing , and the smooth execution of limb movements1,2,3 . transcranial magnetic stimulation and electrical stimulation studies4,5,6 have revealed that the trunk muscles are innervated by fibers from both brain hemispheres . therefore , the impairment of trunk muscle function is less than that of the affected side limb muscle function in patients with unihemispheric stroke6 . however , previous studies have shown that trunk muscle strength is lower in patients with stroke compared with that of healthy age - matched subjects7,8,9,10,11 . bohannon et al.8 reported that stroke patients demonstrated weakness during lateral and forward flexion of the trunk . weakness of the trunk muscles influences balance and activities of daily living ( adl)11 . karatas et al.11 reported a significant positive correlation of trunk muscle strength with balance and adl , suggesting that exercise of the trunk muscles is important for the improvement of adl . although previous studies have reported that overall adl is related to trunk muscle strength11 , the relationships of adl items ( e.g. , eating , grooming , dressing , etc . ) and trunk strength remain unclear . in addition , adl independence is reportedly related to not only trunk muscle strength but also to the motor function of the paretic limbs12,13,14 , sensory deficits15 , 16 , cognitive disorders17 , 18 , apathy19 , and unilateral spatial neglect13 , 20 . accordingly , to clarify the influence of trunk strength on adl , these factors should be evaluated individually whenever possible . therefore , the present study evaluated the influence of trunk muscle strength on individual adl items among mild stroke patients without severe motor or cognitive disorders , or apathy . the study protocol was approved by the institutional ethics review board of northern fukushima medical center ( fukushima , japan ; no.56 ) . the study cohort included 24 stroke patients ( 12 men and 12 women ) who were admitted to the northern fukushima medical center from april 2011 to november 2013 and fulfilled the following inclusion criteria : first stroke ; unilateral supratentorial hemispheric lesion ; and the absence of severe paralysis ( a maximum of 4 motor function items of the stroke impairment assessment set21 , 22 ( sias ) , severe sensory deficits ( a maximum of 2 sensory items of sias ) , marked cognitive function deterioration [ 5 cognitive items of the functional independence measure23 ( fim ) ] , unilateral spatial neglect ( unilateral spatial neglect item of sias , 3 ) , and apathy [ vitality index24 , 8 ] . the mean patient age was 70.5 years , and the mean time from stroke onset was 63.5 days . we evaluated sias21 , 22 , the berg balance scale ( bbs)25 , and fim scores23 , conducted a simple test for evaluating hand function ( stef)26 , 27 , and measured grip strength . sias is a tool for measuring stroke impairment and includes the following items : motor function , muscle tone , sensory function , range of motion , pain , trunk function , visuospatial function , speech , and unaffected side function . the bbs25 ( score range , 056 ) is designed to measure the balance of the elderly and consists of 14 items , including balance while sitting and standing on one leg , which requires a high level of balance ability . the stef26 , 27 ( score range , 0100 ) is a standardized test for assessing upper extremity function . the grip strength of the affected and unaffected hands was recorded two times in the sitting position using a squeeze dynamometer . the motor domain has 13 items in the areas of self - care , sphincter control , transfer , and locomotion . the 24 stroke patients were divided into 2 groups according to the score for abdominal strength on the sias : a nonweakness group , including patients with a score of 3 ( n = 15 ) , and a weakness group , including patients with a score of 2 ( n = 9 ) . subject characteristics are listed in table 1table 1.demographic and stroke - related characteristics of the study subjectsnonweakness group(n=15)weakness group(n=9)age ( yrs)66.2 13.3 * 77.7 14.4days post - stroke62.7 15.564.9 15.5women ( % ) 5344right side hemiparesis ( % ) 6067significant difference between groups . although there were no significant differences in the time since stroke onset , gender , and the side of the affected limb , there was a significant difference in age between the two groups . significant difference between groups the t - test was used to compare age , time since stroke , and time since admission between the nonweakness and weakness groups . gender , side of the affected limb , and type of cva were compared using the test . sias , bbs , stef , grip strength , and fim scores were compared between the two groups using the mann - whitney test . spss for windows software ( version 22 ) was used for all statistical analyses . as shown in tables 2table 2.comparison of the two groups stroke impairment assessment setitemsnonweakness groupweakness groupmedianrangemedianrangemotor functionknee - mouth test445545finger - function test445545hip - flexion test545545knee - extension test545545foot - pat test545545muscle toneu / e muscle tone323323l / e muscle tone323323u / e deep tendon reflex213323u / e deep tendon reflex313323sensationu / e light touch323323l / e light touch323323u / e position33323u / e position33323range of motionu / e rom323323l / e rom323323pain323323trunk functionverticality test33323unaffected side functiongrip strength213223quadriceps strength323313visuo - spatial deficit3333speech323313total score716175686474abdominal muscle strength3 * 3212significant difference between groups . there was a significant difference in the abdominal muscle strength because subjects were divided into two groups according to it . u / e : upper extremity ; l / e : lower extremity ; rom : range of motion and 3table 3.comparison of the two groups grip strength and stefoutcomenonweakness groupweakness groupmeansdmeansdaffected side grip strength18.412.817.79.3unaffected side grip strength27.811.922.37.6affected side stef80.418.575.718.3unaffected side stef93.05.989.09.2stef : a simple test for evaluating hand function . there was no statistically significant difference in grip strength and stef between the two groups . , scores for abdominal muscle strength on the sias and bbs were significantly lower in the weakness group than in the nonweakness group . however , there were no significant differences in sias items except abdominal muscle strength , grip strength , and stef score between the two groups . there was a significant difference in the abdominal muscle strength because subjects were divided into two groups according to it . u / e : upper extremity ; l / e : lower extremity ; rom : range of motion stef : a simple test for evaluating hand function . there was no statistically significant difference in grip strength and stef between the two groups . with respect to adl , dressing the upper and lower body , toilet use , transfer to bed , and walk items as well as the motor domain score and total score on the fim were significantly lower in the weakness group than in the nonweakness group ( table 4table 4.comparison of the two groups berg balance scale and functional independence measure scoresitemsnonweakness groupweakness groupmedianrangemedianrangeberg balance scale50.2 6.841.211.8fimself - careeating767757grooming767757bathing757517dressing upper body 5 * 67537dressing lower body 7 * 67527toileting 7 * 57646sphincter controlbladder management757657bowel management757657transferbed , chair , wheelchair7 * 67657toilet757657tub , shower537517locomotionwalk / wheelchair 6 * 47517stairs517517communicationcomprehension757657expression757757social cognitionsocial interaction77767problem solving657657memory757757fim motor score 84 * 7391665091fim cognitive score342735322834fim there were no significant differences in cognitive items and cognitive domain scores on the fim between the two groups . trunk strength weakness as well as motor paralysis and sensory deficits frequently occur after stroke7,8,9,10,11 . disuse may be one of the causes of muscle weakness9,10,11 . in this study , the relationships between adl items and the abdominal muscle strength of stroke patients were investigated . our results revealed significant differences in the scores for balance and the adl items of independent dressing , toilet use , transfer , and locomotion between the weakness and nonweakness groups . we reasoned that the major factor influencing these differences in scores was abdominal muscle strength , because there were no differences in scores for the motor and cognitive items other than abdominal muscle strength . although the correlation of abdominal muscle strength with transfer and locomotion has been reported11 , 28 , this is the first report , to our knowledge , to identify the relationship of abdominal muscle strength with the ability to dress and use the toilet . dressing requires a high level of trunk stabilization because it involves limb movements and shifts in the center of gravity while sitting without back support or standing . with regard to toilet use , adjustment of clothing before and after toilet use while standing and maintaining perineal hygiene requires the ability to control the trunk . on the other hand , it is believed that eating , grooming , and bathing require neither abdominal muscle strength nor balance because these activities can be performed even in a seated position using a backrest . first , there was a significant difference in mean age between the two groups . although there was no significant difference in motor and cognitive functions between groups , the possibility that adl are influenced by age - induced deterioration ( e.g. , agility and endurance ) can not be overlooked . third , although the subjects in this study were mild stroke patients , the influence of abdominal muscle strength on adl would be different in severe stroke patients , such as those with severe paralysis and cognitive disorders . finally , although the present study clarified some of the relationships between abdominal muscle strength and adl items , it is unknown whether or not exercise to build abdominal muscle strength can improve balance and the ability to dress , use the toilet , transfer , or walk . however , several authors have reported that trunk stabilization exercises improve the abdominal muscle strength and balance of stroke patients29 , 30 . therefore , there s a possibility that such exercises could improve the performance of these adl items by stroke patients with mild paralysis . Output:	[ purpose ] the trunk muscles frequently become weak after stroke , thus impacting overall activities of daily living . however , activities of daily living items closely related with trunk strength remain unclear . this study aimed to clarify the influence of trunk muscle weakness on activities of daily living items . [ subjects ] the subjects were 24 stroke patients who fulfilled the following inclusion criteria : first stroke and the absence of severe paralysis , marked cognitive function deterioration , unilateral spatial neglect or apathy . [ methods ] according to abdominal strength , the 24 patients were divided into a nonweakness group and a weakness group . for the assessment , we used the stroke impairment assessment set , the berg balance scale , a simple test for evaluating hand function , grip strength , and functional independence measure scale scores and the results were compared between the groups . [ results ] the berg balance scale score and scores for dressing , toilet use , transfer to bed , and walk items of the functional independence measure were significantly lower in the weakness group than in the nonweakness group . [ conclusion ] our results suggest that weakness of the abdominal muscles adversely impacts the balance of patients with mild stroke as well as their ability to dress , use a toilet , transfer , and walk . trunk training , including abdominal muscle exercises , can effectively improve the performance of these activities of daily living items .
PubmedSumm118873	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: recent genome - wide transcriptome studies have revealed that the majority of the mammalian genome is transcribed , thereby giving rise to a range of coding and noncoding rna ( ncrna ) transcripts . the latest human gencode release ( version 24 ) , presented by the encyclopedia of dna elements consortium ( encode ) , showed that the human genome is composed of 60554 genes ( figure 1 ) . among those , 19815 are protein - coding genes , whereas the remaining two - thirds of the genome represents noncoding rna genes ( 15941 long noncoding rna genes , 9882 small noncoding rna genes , and 14505 pseudogenes ) . noncoding rnas are predominant in the genome and are classified as either housekeeping or regulatory noncoding rnas . housekeeping noncoding rnas are constitutively expressed and they function as key regulatory molecules of many cellular processes . this group includes ribosomal ( rrna ) , transfer ( trna ) , small nuclear ( snrna ) , and small nucleolar rnas ( snornas ) . the second group , regulatory noncoding rnas , is divided into short ncrnas ( < 200 nucleotides ) or long noncoding rnas ( lncrnas , > 200 nucleotides ) . short ncrnas are represented by micrornas ( mirnas ) , small interfering rnas ( sirnas ) , and piwi - associated rnas ( pirnas ) , and , in few cases , by antisense rnas and enhancer rnas ( ernas ) . long noncoding rnas group includes antisense rnas and enhancer rnas ( ernas ) [ 13 ] ( figure 2 ) . in this review , this class of ncrnas was first discovered in the mouse during large - scale sequencing of full - length cdna libraries . generally , lncrnas were characterized as transcripts longer than 200 nucleotides with some features typical for protein - coding mrna . they are transcribed by rna - polymerase ( pol ) ii , capped on the 5 end , polyadenylated , and commonly expressed as alternatively spliced variants . moreover , lncrnas were found to have the same trimethylation marks of h3k4 and h3k36 at their promoters and transcribed regions . in contrast to mrna , lncrnas usually contain intron / exon structure , they are expressed at lower levels , often in a tissue - specific manner , and their sequence is poorly evolutionary conserved . additionally , they do not possess open reading frames ( orfs ) , 3 utr , and termination regions ; thus the majority have limited coding potential . nevertheless , recent studies have demonstrated that some lncrnas can be associated with polysomes and ribosomes , suggesting that they may act as coding transcripts and give rise to small peptides . an emerging number of studies related to the discovery of new lncrnas and their position to the nearest protein - coding genes have resulted in the introduction of a new nomenclature for these molecules . long noncoding rnas may be classified into five categories : ( 1 ) sense lncrnas that overlap the nearest protein - coding genes at the same strand ; ( 2 ) antisense lncrnas located across the exons of protein - coding genes from the opposite strand ; ( 3 ) bidirectional lncrnas transcribed on the opposite strand within 1 kb from the nearest protein - coding gene ; ( 4 ) intronic lncrnas that overlap intronic regions of coding genes in either the sense or antisense orientation ; ( 5 ) intergenic lncrnas that represent the largest group of lncrna ; they are located between protein - coding genes but are at least 1 kb away from the nearest protein - coding gene ( figure 3 ) . in recent years , numerous studies have aimed to identify functions of newly discovered long noncoding rnas . although the primary role of lncrnas was their epigenetic regulation of protein - coding gene expression , only a limited number of such long noncoding transcripts have been identified . it was soon discovered that lncrnas play a role in variety of biological process , acting in the nucleus , or in the cytoplasm , or in both . functions of lncrnas are manifested by three types of interaction : rna - rna , rna - dna , and rna - protein , all of which depend on the site of action . in the nucleus , for example , the main role of lncrnas is assumed to be epigenetic imprinting . one of the best - described mechanisms of lncrnas action during the epigenetic regulation is the x chromosome inactivation , in which x chromosome inactive - specific transcript ( xist ) plays a key role . recent studies demonstrated that lncrnas can interact with chromatin remodeling complexes including polycomb repressive complex ( prc2 ) 2 , trithorax / mll , and h3k9 methyltransferase g9a , acting as docking platforms to specific genomic loci . these protein complexes modify dna methylation patterns via trimethylation leading to transcriptional repression ( prc2 ) or activation ( trithorax / mll ) of the lncrna target genes . numerous lncrnas have been recognized as scaffolds for inhibitory prc2 including xist , kcnq1ot1 , and hotair [ 8 , 25 ] . other lncrnas , like hottip , directly bind to protein complexes of trithorax / mll . in these situations , , it has been postulated that these lncrnas are guides for chromatin - modifying complexes , where they first recognize the target localizations at the chromatin , bind to them , and then form docking platforms for protein partners . in addition to regulation of genomic imprinting , lncrnas are also involved in the control of gene expression at the transcriptional level . lncrnas can directly interact with transcription factors , acting as decoys or inhibitors for their binding to the target dna sequence . for example , two lncrna molecules , lethe and p50-associated cox-2 extragenic rna ( pacer ) , have been shown to interact with different subunits of nf-b , thus preventing it from binding to the promoter region of the target gene [ 10 , 27 ] . moreover , lncrnas exert their regulatory function during mrna processing and stability , interacting with the heterogeneous nuclear ribonucleoproteins ( hnrnps ) . an example of this type of rna - protein linkage is demonstrated for several lncrnas including lincrna - p21 , lincrna - cox2 , or thril ; thus they affect either activation or repression of target genes . other actions of lncrna in the nucleus are manifested by alternative splicing regulation and subnuclear compartment formation ( figure 4 ) . in the cytosol , lncrnas exert their function by interacting with target mrnas ( or mirnas ) through base - pairing . in this manner , lncrnas may either stabilize ( e.g. , bace1-as prevents mirna - induced repression of bace1 transcript ) or decay ( e.g. , 1/2-sbsrnas bind to the alu element of smd target mrnas within the 3 utr region ) target transcripts . moreover , lncrnas promote translation of transcripts ( e.g. , antisense uchl1 interacts with uchl1 mrna , resulting in recruitment of ribosomes ) or repress this process ( e.g. , lincrna - p21 binds to target mrna causing recruitment of translation repressors ) ( figure 4 ) . inflammation is a complex process , aiming to defend the body against harmful agents by removing or neutralizing them in order to restore tissue homeostasis . the complexity of this process results from the broad spectrum of inflammatory pathways , various inflammatory inducers , sensors , and mediators . in the classic view , the inflammatory response is induced immediately after stimulation by the inflammatory stimuli , such as a bacterial pathogen . cells , such as neutrophils , dendritic cells ( dcs ) , and macrophages , express evolutionarily conserved toll - like receptors ( tlrs ) on their surface . the tlr family is composed of several classes of transmembrane proteins and recognizes specific structures present on the microbes , known as pathogen - associated molecular patterns ( pamps ) . induction of tlrs triggers a multistep signaling cascade , thereby resulting in the modulation of gene expression involved in the immune response . key processes regulated by tlrs are related to the secretion of various mediators by immune cells , phagocytosis , cell migration , metabolic reprogramming , and tissue repair . in general , based on the length , the inflammatory response can be classified into acute or chronic . acute inflammation usually develops locally , and its role is to eliminate toxic agents , repair damaged tissue , and restore homeostasis . in some circumstances , local inflammation might be greater , therefore called a generalized inflammatory response , which is associated with the response of the whole organism . although the acute phase leads to the beneficial recovery of the injured tissue and healing , this nonspecific immune process could have also negative effects . without the proper resolution phase , it can easily turn into a chronic state . chronic inflammation may appear after the switch from the acute phase , and it is characterized by the specific , long - term cellular , and humoral immune response present at the site of tissue injury . in consequence , it may significantly contribute to dangerous pathophysiological changes and initiate the development of chronic diseases . each inflammatory stage one such factor is nf-b ( nuclear factor kappa - light - chain - enhancer of activated b cells ) , representing a family of transcription factors . nf-b plays an important role in gene expression regulation of multiple factors involved in immune , acute phase , and inflammatory responses . nf-b , in addition to controlling the development and function of the immune system , is required in other physiological processes such as suppression of apoptosis and cell proliferation and differentiation . in mammals , the active form of nf-b is composed of homo- and heterodimers of the nf-b family members , which can be divided into five different subunits : p50 , p52 , p65 ( rela ) , c - rel , and relb . all of these share homology of the specific n - terminal domain responsible for the dimerization and binding to target dna sequences . depending on the local cytokines produced by the immune cells , nf-b also controls macrophage relocalization , activation , and differentiation into two different phenotypes : proinflammatory ( m1 ) or anti - inflammatory ( m2 ) . in response to proinflammatory cytokines , nf-b is also involved in the activation of t lymphocytes , which proliferate and secrete cytokines such as interferon gamma ( ifn ) , interleukin 6 ( il-6 ) , or tnf-. the result of nf-b activation is stimulation of proinflammatory cytokine production by macrophages and t lymphocytes , thereby enhancing the inflammatory response . it is characterized by an excessive fat accumulation and enhanced production of proinflammatory cytokines / chemokines by adipose tissues . it is commonly caused by a combination of excessive food intake , lack of physical activity , and genetic susceptibility . a great majority of obese individuals present features of the metabolic syndrome : ( a ) increased waist circumference , ( b ) insulin resistance , ( c ) hyperglycemia , ( d ) hypertension , and ( e ) hypertriglyceridemia . appearance of these symptoms is associated with a high risk of serious disease development , including type 2 diabetes , cardiovascular diseases , , nonalcoholic fatty liver disease ( nafld ) , and even some cancers . the mechanism of metabolic disorder development is still not fully understood ; nevertheless numerous studies have suggested an adipocyte dysfunction as a main cause of metabolic system failure . in this pathological state , adipose tissue secretes various mediators , including cytokines , inducing a chronic , low - grade inflammatory response that results in recruitment of immune cells into the tissue . the excessive accumulation of tissue fat leads to disturbance both in the secretory and in the storage functions of adipocytes . it is postulated that the excessive fat mass induces the production of reactive oxygen species and the development of chronic oxidative stress in patients with obesity and metabolic dysfunction [ 44 , 45 ] . in adipose tissue of obese patients is observed severe inflammatory response , characterized by high production of cytokines and increased infiltration of immune cells , including monocytes , stimulated to differentiate into macrophages and lymphocytes t , activated to proliferate and secrete cytokines [ 46 , 47 ] . cytokines secreted by activated macrophages act on tlrs present on the surface of adipocytes , stimulating them to produce adipokines and cytokines . based on these observations , it has been found that the reactions of both the immune and metabolic systems are closely connected , and they play an important role in the development of metabolic disorders . adipocytes play a central role in energy homeostasis by fine - tuning the equilibrium between nutrient deposition ( white adipose tissue , wat ) and energy expenditure ( brown adipose tissue , bat ) . additionally , adipose tissue acts as an endocrine organ by secreting factors ( adipokines ) that regulate whole body energy and glucose homeostasis . adipogenesis is a complex process governed by a network of transcription factors , cofactors , and signaling intermediates from numerous pathways . the transcriptional cascade that regulates adipocyte differentiation is predominantly driven by peroxisome proliferator - activated receptor gamma ( ppar ) , shown to be both necessary and sufficient for adipogenesis . importantly , adipogenesis is highly regulated not only by ppar but also by the coordinated effects of other transcription factors including ccaat / enhancer - binding proteins ( c / ebps ) , kruppel - like factors ( klfs ) or wingless proteins ( wnt ) , and transcriptional cofactors [ 5254 ] . in recent years , there has been growing attention paid to noncoding rnas as a novel , cell intrinsic regulatory mechanism . specifically , lncrnas are now emerging as important regulators of gene expression both on the transcriptional and on the posttranscriptional levels . long noncoding rnas are being discovered using modern techniques of microarray or next - generation sequencing . however , only small portions have been fully characterized . in the case of adipogenesis , there is wide expression of lncrnas , controlling a variety of genes involved in the formation , differentiation , and activation of adipocytes ( figure 5 ) . steroid receptor rna activator ( sra ) lncrna was described for the first time as a molecule regulating adipogenesis . it was shown that lncrna sra , initially identified as a coactivator of steroid receptors , also acts as a transcriptional coactivator of ppar [ 55 , 56 ] . lncrna sra promotes adipocyte differentiation by binding to the n - terminal portion of ppar and enhances its transcriptional activity . additionally , its overexpression significantly increased mrna and protein levels of adipocyte master regulators ppar and c / ebp as well as ppar target genes . moreover , gene expression profiling showed that lncrna sra regulates expression of genes related to various cellular processes including cell cycle and insulin transduction pathways . further experiments proved that lncrna sra overexpression inhibits phosphorylation of p38 mitogen activated protein kinase ( mapk ) and c - jun nh2-terminal kinase ( jnk ) in the early differentiation of st2 mesenchymal precursor cells . in contrast , knockdown of lncrna sra increased p38 and jnk phosphorylation while reducing insulin receptor mrna and protein levels , which led to decreased downstream signaling . supporting that data , sra knock - out mice ( sra ) are resistant to high fat diet ( hfd ) induced obesity . after 14 weeks of hfd , sra mice are characterized by reduced wat mass and decreased expression of adipocyte genes such as adiponectin or fatty acid - binding protein 4 . the lean phenotype is also associated with smaller adipocytes in wat compared to wt mice , reduced liver mass , fewer lipid droplets in the liver , and decreased expression of lipogenesis - associated genes . finally , sra animals have improved insulin sensitivity . in a recent paper , xiao and coworkers identified lncrna adinr ( adipogenic differentiation induced noncoding rna ) that , in cis , transcriptionally activates c / ebp. it was upregulated 2030-fold during the course of adipogenesis and was transcribed from a position ~450 bp upstream of the c / ebp gene . knockdown of lncrna adinr with sirna resulted in a dramatic adipogenic defect as shown by a decreased number of oil red o positive cells and reduced adipogenic transcripts c / ebp , ppar , fatty acid - binding protein 4 , and lipoprotein lipase . importantly , inhibition of adipogenesis caused by depletion of lncrna adinr was rescued by overexpression of c / ebp. the lncrna adinr mechanism of action relies on its binding to pa1 followed by recruitment of mll3/4 histone methyltransferase complexes . in turn , that causes an increase in h3k4me3 and a decrease in h3k27me3 histone modification in the c / ebp locus during adipogenesis . expression of the pu.1 gene gives rise to both the mrna encoding pu.1 protein and antisense ( as ) lncrna originating from a promoter in the antisense strand of intron 3 . the protein pu.1 was originally demonstrated to be a key transcription factor regulating hematopoiesis , but recent studies revealed that it is also expressed in 3t3-l1 preadipocytes and murine adipocytes isolated from wat [ 60 , 61 ] . gain and loss of function studies established the pu.1 protein as an inhibitor of 3t3-l1 preadipocyte differentiation , acting via downregulation of ppar . on the other hand , pu.1 as lncrna promotes adipogenesis through preventing pu.1 mrna translation by binding to pu.1 mrna to form an mrna / as lncrna duplex . formation of this sense - antisense rna duplex was also confirmed in porcine adipocytes by an endogenous ribonuclease protection assay combined with rt - pcr . in line with the previous data , expression of ppar and fatty acid synthase ( fasn ) was significantly upregulated in the lncrna pu.1 shrna treated group . in a number of studies , global transcriptome profiling was used to select specific lncrnas either involved in adipogenesis or characteristic for adipocytes specifically isolated from wat or bat . in a seminal study done by sun and coworkers , the transcriptome of primary brown and white adipocytes , preadipocytes , and cultured adipocytes was profiled . scientists identified 175 lncrnas that were specifically regulated during adipogenesis . to further validate lncrnas that are functionally important for adipogenesis , researchers selected the top 20 lncrna genes based on the following criteria : ( i ) significant upregulation in both brown and white fat cultures , ( ii ) binding to ppar or cepb promoters , and ( iii ) independent validation of adipose - specific expression . by using rnai - mediated loss of function , the top 10 most important lncrnas were selected and called regulated in adipogenesis ( lncraps ) in order to highlight their key role in proper differentiation of adipocyte precursors . in comparison to white adipocytes , brown adipocytes have a higher mitochondrial content and express uncoupling protein 1 ( ucp1 ) , which disperses chemical energy through heat production . brown adipose tissue helps to regulate energy expenditure in rodents and newborn babies , but it has been considered to have no physiologic relevance in adults [ 65 , 66 ] . however , recent studies demonstrated that metabolically functional bat is also present in adult humans . as a result , an understanding of bat physiology might provide an effective treatment of obesity or other metabolic disorders . identification of the lncrnas crucial for bat differentiation and function was done using whole transcriptome rna sequencing . next , gain and loss of function studies established lncrna blnc1 as a potent activator of thermogenic adipocyte differentiation . it functions upon formation of rna - protein complex with the early b cell factor 2 ( ebf2 ) transcription factor to stimulate bat formation . additionally , lncrna blnc1 itself is a target of ebf2 , thereby forming a feed - forward regulatory loop . on the other hand , despite its stimulatory effects on brown preadipocyte differentiation , lncrna blnc1 failed to promote differentiation of 3t3-l1 cells into ucp1 positive adipocytes . another global profiling of gene expression during mouse brown fat cell differentiation , followed by candidate lncrnas genomic context analysis , pathway analysis , and gene ontology enrichment of their associated protein - coding genes was recently described . in this study , scientists identified three lncrnas ( gm15051 , tmem189 , and cebpd ) associated with their flanking coding genes ( hoxa1 , c / ebp , and c / ebp ) that participated in adipose commitment . more recently , rna - seq analysis of murine brown , inguinal white , and epididymal white fat allowed for identification of lncrna cluster enriched in bat . among them , authors showed that bate1 binds to the heterogeneous nuclear ribonucleoprotein u , a factor also required for bat formation . finally , interactions of lncrnas with micrornas in the context of adipogenesis were also described . as demonstrated by gernapudi and coworkers , the mir-140/lncrna neat1 signaling network is necessary for adipogenesis . adipocyte derived stem cells isolated from mir-140 knock - out mice had dramatically decreased adipogenic capabilities found to be associated with the downregulation of lncrna neat1 expression . they also found that the physical interaction with mir-140 in nucleus led to increased expression of neat1 . excessive fat accumulation not only causes pathological expansion of adipose tissue but also leads to triglyceride deposition in the liver . presence of lipid droplets in excess of 5% of total hepatocytes is a diagnostic hallmark of nonalcoholic fatty liver disease ( nafld ) . although most patients suffer from a mild course of illness , approximately 25% of cases progress and can subsequently lead to the development of steatohepatitis , hepatic fibrosis , liver cirrhosis , and hepatoma . scientists and physicians estimate that between 20% and 30% of west 's general population suffers from nafld , which makes this affects more than a billion people worldwide . to address questions about the global expression pattern and functional contribution of lncrnas during nafld , sun and coworkers analyzed microarray expression using rna extracted from liver biopsies of healthy patients and those suffering from nafld . in this analysis , 535 lncrnas were found upregulated in nafld samples compared with controls and 1,200 were downregulated in nafld ( figure 5 ) . out of these , seven nafld samples that had highly up- or downregulated gene expression were validated by quantitative real - time pcr ( qpcr ) . three lncrna results obtained by qpcr were different in comparison to the microarray data , showing no change between analyzed groups . however , changes in other selected hits were confirmed , highlighting the importance of microarray data validation . pancreatic islets , through the secretion of endocrine hormones such as insulin and glucagon , play a key role in metabolic homeostasis . however , one of the most common malfunctions of -cells is caused by lack of insulin , leading to the development of diabetes . additionally , diabetes may develop as a result of insulin resistance , a condition in which the body can not effectively use the insulin produced by -cells . as a result , blood sugar levels are deregulated and various tissues are exposed to prolonged hyperglycemia that , over time , causes serious damage to many of the body 's systems . it should be emphasized that hyperglycemia , a hallmark of diabetes , can cause both acute and long - term complications like cardiovascular disease , stroke , foot ulcers , ketoacidosis , or hyperosmolar coma . based on etiology , who classifies diabetes into four categories , but the vast majority of cases fall into two broad etiopathogenetic groups : type 1 diabetes mellitus ( t1 dm ) or type 2 diabetes mellitus ( t2 dm ) . accounting for 510% of all cases , t1 dm is characterized by the loss of insulin producing -cells due to an autoimmune reaction . type 2 diabetes mellitus represents 9095% of all cases and , unlike t1 dm , is strongly associated with patients ' lifestyle . a number of lifestyle factors are known to be important for development of t2 dm including obesity ( bmi above 30 ) , lack of physical activity , poor diet , or stress . it is a chronic disease that begins with insulin resistance , a condition in which cells ( mostly adipocytes , hepatocytes , and muscle cells ) fail to properly absorb and metabolize glucose . as a result , -cells increase insulin production to overcome hyperglycemia , but this compensatory mechanism is transient and generally fails over time . intensified metabolism of -cells leads to a gradual loss of their endocrine function and finally causes -cell apoptosis . who , in 2014 , the global prevalence of diabetes was estimated to be 9% among adults aged over 18 years and it is expected to double before 2030 [ 75 , 80 ] . additionally , experts project that , in 2030 , diabetes will be the 7th leading cause of death . initial studies aimed at identification of specific lncrnas expressed in murine and human pancreatic islets were done in 2012 [ 81 , 82 ] . by using next - generation sequencing , scientists revealed a large collection of 1359 intergenic lncrnas expressed in murine -cells ( figure 5 ) . many of them were highly tissue - specific , but their function was not evaluated , and future experiments are still needed . similar numbers of 1128 intergenic and antisense lncrnas were identified in human -cells and many of them ( e.g. , hi - lnc12 and hi - lnc77 ) were highly tissue - specific . additionally , lncrna - encoding genes were preferentially located near genes encoding important regulators of -cell function , development , and transcription . one of them , lncrna hi - lnc25 , conserved between mouse and human , was shown to positively regulate glis3 mrna . glis3 encodes a pancreatic islet transcription factor that is mutated in monogenic diabetes and contains t2 dm risk variants [ 83 , 84 ] . in the same set of experiments , scientists also showed that selected lncrnas ( e.g. , hi - lnc12 and hi - lnc25 ) are linked to -cell differentiation program as their expression was significantly higher in human islets when compared to the embryonic pancreas . moreover , the addition of glucose to in vitro -cell culture induced expression of some lncrnas , suggesting their importance for mature islet cell physiology . finally , authors showed deregulation of islets ' lncrnas in t2 dm by comparing profiles of lncrnas in islets from 19 nondiabetic and 16 t2 dm donors . two lncrnas , namely , kcnq1ot1 and hi - lnc45 , were significantly increased or decreased in t2 dm islets , respectively . seven lncrnas specific for -cells , as reported by morn and coworkers , were also discussed in another study that analyzed pancreatic islets from 89 individuals with or without diabetes . microarray analysis , rna sequencing , and exome sequencing methods enabled researchers to identify 493 lncrnas that were differentially expressed in the pancreatic islets . out of those , 17 long intergenic noncoding rnas ( lincrnas ) were significantly associated with donor 's hba1c levels , and two ( loc283177 and snhg5 ) were also involved in gene expression regulation . to obtain insight into functional target genes of lncrnas loc283177 and snhg5 , the authors performed a coexpression analysis , linking their expression with all other genes in pancreatic islets . lncrna loc283177 levels correlated with expression of genes that play a key role in islet function , namely , synaptotagmin 11 , map - kinase activating death domain ( madd ) , and paired box 6 ( pax6 ) . synaptotagmin 11 is known to regulate the exocytosis of insulin and madd proinsulin synthesis , and pax6 is involved in development of pancreatic islets [ 85 , 86 ] . supporting these findings , lncrna loc283177 expression was found to be directly associated with insulin exocytosis in the islets . insulin is secreted from -cells in response to glucose , while other nutrients such as free fatty acids and amino acids can augment glucose - induced insulin secretion . in addition , various hormones ( e.g. , leptin , growth hormone , glucagon like peptide-1 , and estrogen ) also regulate insulin secretion . as a result , -cells are called a metabolic hub in the body that coordinate nutrient metabolism with endocrine system . insufficient insulin production , or insulin resistance , is a prime cause of diabetic complications . among the many tissues affected by hyperglycemia , endothelial cells are very important because they are implicated in pathogenesis of diabetes - related microvascular and macrovascular complications . one of these complications , diabetic retinopathy , was recently shown to be influenced by lncrna malat1 ( metastasis - associated lung adenocarcinoma transcript 1 ) ( figure 5 ) . in a mouse model of streptozotocin - induced diabetes microarray analysis , followed by qpcr validation of selected genes , allowed for identification of 303 differentially expressed lncrnas including 214 downregulated and 89 upregulated genes in diabetic versus nondiabetic samples . one gene , lncrna chr19 : 57956895802671 , a murine ortholog of human lncrna malat1 , had a greater than 10-fold upregulation in diabetic retinas . lncrna malat1 was previously described in humans to be deregulated in several solid tumors and was associated with cancer metastasis and recurrence . it was shown to be significantly upregulated in a rf/6a cell model of hyperglycemia , in the aqueous tumor samples and in fibrovascular membranes of diabetic patients . to further investigate the molecular mechanism of lncrna malat1 action , scientists decided to analyze its function in retinal vasculature and endothelial cell dysfunction in diabetes mellitus . lncrna malat1 knockdown in retinas of db / db mice resulted in amelioration of diabetic retinopathy as manifested by reduced apoptosis of retinal cells and pericytes . importantly , after administration of lncrna malat shrna , scientists observed decreased retinal vascular permeability as measured by evans blue leakage . moreover , in vitro tests showed that lncrna malat1 knockdown decreased retinal endothelial cell proliferation , migration , and tube formation . in rf/6a endothelial cells , lncrna malat1 acts via induction of p38 mapk signaling , and its silencing reduced phosphorylated p38 level but had no effect on phosphorylated erk1/2 or jnk1/2 . pretreatment of rf/6a cells with sb203580 , a p38 mapk pathway inhibitor , strongly blocked the effect of lncrna malat1-induced cell proliferation . more recently , the same research group reported that lncrna miat ( myocardial infarction - associated transcript ) also regulates diabetes mellitus microvascular dysfunction , acting as a competing endogenous rna ( figure 5 ) . similar to a previous report , lncrna miat expression was increased in diabetic retinas and endothelial cells cultured in high glucose medium . as shown by in vivo tests , lncrna miat knockdown ameliorated diabetes mellitus induced retinal microvascular dysfunction . in line with in vivo data , silencing of lncrna miat in endothelial cells cultured in vitro led to an inhibition of proliferation , migration , and tube formation . lncrnas may act as an mrna molecular sponge and regulate mirnas available for binding their target mrnas . bioinformatics suggested that the lncrna miat sequence contains 4 putative mirna binding sites including mir-29a-3p , mir-29b-3p , mir-29c-3p , and mir-150 - 5p . one of these , mir-150 - 5p , was proven to directly target lncrna miat in endothelial cell both in vitro and in vivo . this particular mirna is of great importance for angiogenesis because it regulates the expression of vegf , a key angiogenic factor involved in physiological and pathological angiogenesis . yan and coworkers proved that miat regulates the expression of mir-150 - 5p target gene vegf creating a critical regulatory loop for endothelial cell function . during angiogenesis , lncrna miat is significantly upregulated , which in turn alleviates the mir-150 - 5p repression effect , thereby upregulating the level of mir-150 - 5p target gene , vegf . in contrast to lncrna miat , lncrna meg3 ( maternally expressed gene 3 ) expression was significantly downregulated in the retinas and endothelial cells of stz - induced diabetic mice upon high glucose and oxidative stress conditions . its knockdown regulated retinal endothelial cell proliferation , migration , and tube formation in vitro . as demonstrated in rf/6a endothelial cells , inhibition of lncrna meg3 by sirna significantly increased levels of phosphorylated pi3k and phosphorylated akt at thr and ser . addition of pi3k inhibitors to cell cultures abrogated the observed phenotype , proving that lncrna meg3 regulates hyperproliferation of retinal endothelial cells through pi3k / akt signaling . additionally , its activation influences endothelial cell biology by modulating angiogenesis , proliferation , and microvascular permeability . Output:	ribonucleic acids ( rnas ) are very complex and their all functions have yet to be fully clarified . noncoding genes ( noncoding rna , sequences , and pseudogenes ) comprise 67% of all genes and they are represented by housekeeping noncoding rnas ( transfer rna ( trna ) , ribosomal rna ( rrna ) , small nuclear rna ( snrna ) , and small nucleolar rna ( snorna ) ) that are engaged in basic cellular processes and by regulatory noncoding rna ( short and long noncoding rna ( ncrna ) ) that are important for gene expression / transcript stability . in this review , we summarize data concerning the significance of long noncoding rnas ( lncrnas ) in metabolic syndrome related disorders , focusing on adipose tissue and pancreatic islands .
PubmedSumm118874	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: both motor blockade and sensory level can be used as a primary endpoint to evaluate the relative potency of local anesthetics . the potency can be determined by investigating the median effective doses ( ed50 ) of motor block using the up - down sequential allocation technique . the ed50 for motor block of several anesthetics ( bupivacaine , levobupivacaine , and ropivacaine ) have been determined . using these approaches , we previously determined the ed50 for motor block of spinal 0.75% plain bupivacaine in adult patients undergoing urological or lower limb surgery , and found this to be 10.22 mg in patients aged 2030 years , and 5.78 mg in those aged 7080 years . some researchers have reported that the concentration of local anesthetic is an important factor determining the maximum sensory level and motor block of spinal anesthesia . reported that the concentration of local anesthetic affected the ed50 for motor block in adults . in our previous study , we also found that the concentration of plain bupivacaine influenced the ed50 in young patients , demonstrating that the ed50 for motor block of intrathecally administered bupivacaine with 0.75% bupivacaine was higher than that of the lower concentration ( 0.375% bupivacaine ) . researchers have found that the spinal cord and nerves changed significantly with age in the biochemical , morphological , and histochemical patterns , and in the anatomical structure [ 1012 ] . it has been reported that age not only affects the compound action potential amplitude of the muscle and its duration on motor and sensory nerves , but also affects the conduction velocity of the motor nerve [ 1517 ] . there are no reports in the literature about the ed50 for motor block in elderly patients using different concentrations of bupivacaine solutions . the aim of the study was to determine the median effective dose ( ed50 ) for motor block using 3 different concentrations of intrathecally administered plain bupivacaine in elderly patients . this study was registered in the chinese clinical trial registry ( i d : chictr - trc-12001897 ) . the local ethics committee of the first college of clinical medical science , china three gorges university , yichang , china , approved the study on july 8 , 2010 . written informed consents were obtained from all patients prior to their enrollment . between october 8 , 2011 and july 8 , 2013 , we enrolled 64 american society of anesthesiologists ( asa ) stage i ii patients aged 70 years undergoing transurethral prostatectomy , anorectal surgery , and under - knee lower limb surgery , with combined spinal and epidural anesthesia ( cse ) . patients with diabetes , obesity , bleeding diathesis , hypersensitivity to amide local anesthetics , neuromuscular disease , or abnormalities of the lumbar vertebrae were excluded . the patients were randomly assigned into 3 groups according to a computer - generated random number table : group 1 received 0.75% bupivacaine ; group 2 received 0.375% bupivacaine ; and group 3 received 0.25% bupivacaine . the anesthesiologist in charge performed the entire anesthetic procedure and 1 nurse assessed the clinical results and collected the data , and was blinded to the local anesthetic dose ; a second nurse was responsible for preparing the research drug according to the assessed results . before the cse was performed , 500 ml of lactated ringer s solution was infused within 30 minutes . for cse , the patient was positioned in the left lateral decubitus position , and punctured at the l3/4 interspace with a 16-gauge tuohy needle . the hole of the needle was oriented in the cranial direction when inserted through the tuohy needle . the study anesthetic solution was injected into the subarachnoid space at a rate of 0.2 ml / second after cerebro - spinal fluid ( csf ) appeared in the spinal needle hub . the epidural catheter was threaded 3 cm into the epidural space , and the patient was placed in a supine neutral position . after the study determinations were made , the patient s position was changed according to the requirements of the surgical procedure . based on our previous research , the initial dose chosen was 7.5 mg ( 1.0 ml ) of the 0.75% plain bupivacaine solution ( bupivacaine . zhaohui company , shanghai , china ) , and the dose interval was set at 0.75 mg ( 0.1 ml ) in all groups . in group 1 , the 0.75% plain bupivacaine solution was used directly ; in the group 2 , a concentration of 0.375% bupivacaine was achieved by adding the same volume of 0.9% saline ; and in group 3 , a concentration of 0.25% bupivacaine was obtained by adding 2/3 volume of 0.9% saline . the subsequent doses of the drug in each group were decided depending on the outcome in the previous patient in the same group according to dixon s up - and - down method . the efficacy of the drug was determined using the modified bromage scale and the hip motor function scale . it was assessed from completion of the spinal injection every minute for 5 min , and at 10 min ( table 1 ) . an ineffective outcome was defined as a bromage and a hip motor function score of 0 in either leg within 5 min of injection . if this occurred , the bupivacaine dose was incremented of 0.75 mg for the next patient in the same group . an effective outcome was defined as a modified bromage and a hip motor function score > 0 in either leg within 5 min of injection . in this case the bupivacaine dose was decreased 0.75 mg for the next patient in the same group . the median ed50 for motor block of bupivacaine was obtained from the midpoints of the ineffective - to - effective crossover . patients were enrolled until 6 pairs were obtained , as per paul and fisher s study . according to our previous experience , a technical failure was defined as a patient that did not feel heat or numbness sensations in the leg and sacral dermatomes with 2 min of spinal injection . then , the same dose was repeated in the next patient of the same group . the highest level of pinprick sensation in the midaxillary line was assessed and recorded at 5 min and 10 min after completion of spinal injection ( table 2 ) . the highest sensory level blocked was also determined , and the duration of the motor blockade was also recorded . ten minutes after spinal injection , supplemental doses of 2% lidocaine were given through an epidural catheter if the level of anesthesia was not sufficient for surgery . general anesthesia was used if required . the number of cases requiring epidural local anesthetic reinforcement and the total volume of local anesthetic used , the number of cases with incomplete motor block ( bromage scale < 2 ) , and the number of cases requiring general anesthesia were recorded . intraoperative monitoring , included noninvasive blood pressure ( bp ) , heart rate ( hr ) , and o2 saturation by pulse oximetry values , were recorded before anesthesia , and at 5 and 10 min after intrathecal injection of bupivacaine . arterial hypotension was defined as a 30% decrease in the systolic bp compared to the baseline value , and was treated by the intravenous administration of 5 mg ephedrine . heart rate decrease to under 55 beats / min was treated with 0.25 mg of atropine . data are expressed as the mean ( sd ) , median ( range ) , or count / number . the means were compared using one - way analysis of variance ( anova ) , while medians ( ranges ) were analyzed by kruskal - wallis one - way analysis , and counts or proportions were analyzed by using the fisher s exact test . the ed50 for motor block was determined according to the up - and - down sequences method of dixon and massey , while the probit regression analysis was used as a backup or sensitivity test . one - way analysis of variance ( anova ) was used for comparisons of the ed50 , and the tukey multiple comparison test was used for multiple comparisons between groups . based on the study by paul and fisher , patients were enrolled until 6 crossovers were obtained ; therefore , we could complete the study enrollment when we had enrolled 64 patients . data are expressed as the mean ( sd ) , median ( range ) , or count / number . the means were compared using one - way analysis of variance ( anova ) , while medians ( ranges ) were analyzed by kruskal - wallis one - way analysis , and counts or proportions were analyzed by using the fisher s exact test . the ed50 for motor block was determined according to the up - and - down sequences method of dixon and massey , while the probit regression analysis was used as a backup or sensitivity test . one - way analysis of variance ( anova ) was used for comparisons of the ed50 , and the tukey multiple comparison test was used for multiple comparisons between groups . based on the study by paul and fisher , patients were enrolled until 6 crossovers were obtained ; therefore , we could complete the study enrollment when we had enrolled 64 patients . the patient characteristics and demographic data were not signifigantly different among the 3 groups ( table 3 ) . one patient in group 1 and 1 patient in group 2 required general anesthesia due to technical difficulty during epidural space detection ; these patients were excluded from the analysis . sixty - two patients were punctured successfully and felt sensations of heat or numbness in the leg and sacral dermatomes within 2 min , indicating that the study drug had been correctly injected into the subarachnoid space . in group 3 , there were 3 patients whose motor nerves were not blocked completely during the entire period of surgery ( bromage scale < 2 ) . there was 1 patient each in group 2 and 3 whose level of analgesia did not allow surgery ; therefore , they were administered epidural supplement drugs . one patient in group 1 needed general anesthesia because the sensory block level was insufficient to start surgery . the number of patients who needed supplemental epidural anesthesia did not differ significantly among the 3 groups . there were no significant differences among the groups in maximum sensory block level at 5 min and 10 min after completion of spinal injection ( table 2 ) . the ed50 for motor blockade of bupivacaine was 6.10 ( 95% ci 5.586.66 ) mg in group 1 , 6.04 ( 95% ci 5.826.28 ) mg in group 2 , and 5.43 ( 95% ci 5.195.67 ) mg in group 3 . the ed50 for motor block of bupivacaine was significantly different among groups ( one - way analysis of variance : p=0.008 ) , and the ed50 for motor block of group 1 was significantly higher than group 3 ( tukey multiple comparison test : p=0.005 ) . using probit regression analysis , the ed50 for motor block was 6.04 ( 95% ci 5.106.89 ) mg in group 1 , 5.90 ( 95% ci 5.356.42 ) mg in group 2 , and 5.30 ( 95% ci 5.055.57 ) mg in group 3 ( table 4 ) . the present study showed that the ed50 for motor block in older patients was significantly different when various concentration of intrathecal plain bupivacaine solutions were used , which was significantly higher when 0.75% bupivacaine was used compared to when 0.25% bupivacaine was used . this study used the motor blocking minimum local anesthetic dose methodology to assess the motor block potencies of various concentrations of anesthetic solution , administered as spinal anesthesia , in older patients . reported that the ed50 for motor block of intrathecal ropivacaine was 50% higher in a 0.1% solution , but this trend was not consistent with our present findings . first , plain ropivacaine has lower lipid solubility , which results in lower distribution of ropivacaine into the cord . second , the plain ropivacaine solution is slightly hypobaric , and the spread is likely to be more dependent on other factors such as injection rate , and volume and doses of ropivacaine . finally , the great difference of anesthetic concentration ( a 10-fold difference ) results in a different trend . in the present study only a 3-fold difference in hyperbaric bupivacaine was used for spinal anesthesia . observed that slightly increasing local anesthetic concentration ( lidocaine ) , and comparing it with a small increase in the dose at a lower concentration , achieved the same degree of motor and sensory block . however , with the plain bupivacaine in the present study , we noted that the doses for motor block were higher in the higher concentration group . this is probably because the density of the local anesthetic solution determines the spread of the anesthetic drugs . according to previous research using highly precise equipment to accurately measure the density of commonly used intrathecal drugs in human csf at 37c , plain bupivacaine is indeed hypobaric [ 2729 ] . in a previous study , we determined the ed50 for motor block with 0.75% plain bupivacaine for spinal anesthesia , and compared the values between adults of various age groups . the ed50 was found to be 5.78 mg in adults aged 7080 years , which is similar to the result of the present study . furthermore , we have measured the ed50 for motor block of 2 different concentrations of bupivacaine ( 0.375% and 0.75% ) in young patients , and observed that the ed50 for motor block of intrathecally administered bupivacaine with higher concentration ( 0.75% ) was higher ( 9.998 mg ) than that of a lower concentration ( 0.375% , 8.890 mg ) . many factors influence the level of spinal sensory anesthesia , including the dose and volume of the anesthetics and the lumbosacral csf volume . . found that the ratio of the long axis and the transection area of the abdomen also affected maximal spinal level . in this study , although dosage variations existed between different individuals and also the volume of bupivacaine solution was different in different groups , the level of sensory analgesia was similar at 5 min and 10 min after spinal injection , differing by just 1 or 2 sensory dermatomes among the 3 groups . this is probably because the volumes of local anesthetic used in our current study ( <3 ml ) are substantially lower than the lumbosacral csf volumes , which have been reported to range from 42.7 to 81.1 ml . previous studies have also shown that the volume of intrathecal bupivacaine is not an important determinant of local anesthetic spread . achieved a t10 sensory peak block level using low hyperbaric bupivacaine doses ( 6 and 7 mg , respectively ) and used head - down tilt to reach it , thus explaining the differences with our work ( lower sensory block level reached ) . for reducing the incidence of hypotension and fast recovery from anesthesia , errando et al . used very low hyperbaric bupivacaine doses ( 3.75 mg ) at very low concentration ( 0.25% ) for fracture repair in the elderly , but some of their patients needed intravenous anesthesia rescue in hip fracture repair surgery . in our study , we determined the ed50 was 5.43 mg in 0.25% plain bupivacaine , a slightly higher dose . the average duration of motor block in the 3 groups assessed here was 150~220 min , with no significant difference among groups . the limitations of our study are : the sample size was obtained in an indirect manner . the volume of csf was not determined in the spine and the height of a patient would affect the sensory level , and also affect the results of this study . ten minutes after injection completion could be an insufficient time lapse to evaluate the motor block and sensory level characteristics during spinal anesthesia . however , we imposed this time limitation due to clinical / practical reasons . moreover , as we have previously described , although the up - and - down method is often used in small samples to determine the ed50 of a drug , the ed95 can not be accurately assessed using this approach . therefore , further investigations are required to determine the ed95 of bupivacaine for different anesthetic concentrations and injection volumes . in addition , although our results showed statistically significant differences , in the clinical setting these could be less important . the concentration of bupivacaine solutions affects the ed50 for motor block with intrathecally administered bupivacaine in elderly patients . the ed50 doses of these 3 concentrations were significantly different and the dose of 0.75% bupivacaine was significantly higher than that of 0.25% bupivacaine . Output:	backgroundthe aim of the study was to determine the median effective dose ( ed50 ) for motor block of various concentrations of intrathecally administered plain bupivacaine.material/methodsbetween 2011 and 2013 , 64 patients aged 70 years , undergoing transurethral , or lower limb surgery with combined spinal and epidural anesthesia in a single hospital were enrolled . the patients were randomized into 3 groups to receive intrathecal 0.75% bupivacaine ( group 1 ) , 0.375% bupivacaine ( group 2 ) or 0.25% bupivacaine ( group 3 ) . spinal anesthesia was achieved using injections of up - and - down doses of 0.75% , 0.375% , or 0.25% plain bupivacaine . the first patient in each group received 7.5 mg bupivacaine , and the testing interval was set at 0.75 mg . the efficacy of motor block in both legs was determined using a modified bromage and a hip motor function scale . the ed50 for motor block was estimated according to the dixon s up - and - down method.resultsthe ed50 for motor block of bupivacaine was 6.10 ( 95% ci 5.586.66 ) mg in group 1 , 6.04 ( 95% ci 5.826.28 ) mg in group 2 , and 5.43 ( 95% ci 5.195.67 ) mg in group 3 . there were significant differences in the ed50 for motor block among the groups ( p=0.008).conclusionsthe ed50 doses for motor block with 3 bupivacaine concentrations were significantly different in elderly patients ; the ed50 dose of 0.75% bupivacaine being significantly higher than that of 0.25% bupivacaine .
PubmedSumm118875	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: are extremely rare . early and accurate diagnosis of the condition based on perinatal history , clinical examination , and radiographic evaluation is essential because of high rate of lethal outcome with delayed therapy and avoid unnecessary laparotomy . we present this case focusing on usefulness of percutaneous needle aspiration under ultrasonographic guidance in the management . a 26-days - old male neonate weighing 2.9 kg presented with a history of abdominal distention for the past 4 days . clinical examination revealed an active infant having abdominal distention and palpable abdominal masses in bilateral upper quadrant . ultrasonography was performed with prosound-4000 ( aloka , japan ) ultrasound unit using 3.5 mhz curvilinear trasducer . gray - scale sonography demonstrated cystic masses with internal echoes and debris at bilateral supra renal area measuring right 7.9 4.3 cm and left 4.4 4.6 cm , respectively [ figure 1 ] . transverse ultrasound image reveals anechoic cystic masses containing internal echoes and debris at bilateral supra renal area and right is measuring more than left color doppler and power doppler imaging confirmed avascular nature of the mass . magnetic resonance imaging of the abdomen was performed with a 1.5 t unit ( sigma ; ge , u.s.a . ) revealed well - defined bilateral suprarenal cystic masses measuring 7.5 5.6 cm on the right side and 4.0 4.5 cm on the left side . the masses were hypointense to muscle on t-1 weighted imaging and markedly hyperintense on t-2 weighted imaging [ figures 2a and b ] . coronal t1-weighted image ( tr / te 395/13 ms ) ( a ) of the abdomen showing a bilateral suprarenal cystic lesion with hypointense signal intensity and coronal t2-weighted image ( tr / te 4000/101 ms ) ( b ) of the abdomen showing a bilateral suprarenal cystic lesion with hyperintense signal intensity ultrasonographic guidance aspiration was done through posterolateral approach using a 20 gauge needle [ figure 3 ] . ninety milliliters of thick pus was aspirated from right suprarenal abscess and 60 ml from left side and the aspirate was sent for bacteriological study . abdominal distention was reduced within 24 h. serial ultrasonography showed gradual regression of the residual adrenal cavities . the culture of aspirated purulent fluid revealed no growth and there was no clinical evidence of adrenal insufficiency . after 3-months follow up ultrasonography revealed the complete resolution of bilateral suprarenal mass with foci of calcification . longitudinal ultrasound image reveals anechoic cystic mass with wall calcification and needle in the lesion during procedure two theories have been proposed for the development of neonatal adrenal abscess : first , hematogenous bacterial seeding of a normal adrenal gland and second , the seeding of a neonatal adrenal hemorrhage with subsequent abscess formation . in some cases , it is likely that most adrenal abscesses begin with adrenal hemorrhage that is not infrequently associated with traumatic or difficult delivery , hypoxia , sepsis , and coagulopathy . in most reported cases , bacterial examination of abscess material revealed e. coil , or staph aureus but streptococcus , bacteriodes , echovirus , and herpes simplex could also be isolated . differential diagnosis of adrenal collection includes adrenal hemorrhage , cyst , neuroblastoma , wilm 's tumor , renal duplication with dilatation of the upper segment and hydronephrosis . an early and accurate diagnosis of neonatal adrenal abscess is essential to avoid a potentially lethal outcome , as bilateral adrenal abscess in our case . extension of the abscess with involvement of adjacent organs has been reported . a case of retroperitoneal pulmonary fistula caused by a neonatal adrenal abscess ultrasonography and intravenous pyelography ( ivp ) were shown to be useful for diagnosis . at present , ct scan and/or magnetic resonance imaging ( mri ) should enable one to usually arrive at the correct preoperative diagnosis . mondor et al . , described successful drainage using a pigtail catheter placed under ultrasonography guidance . the authors stressed the need to closely follow up the patient by regularly repeated ultrasonography until the adrenal gland is back to normal size . the mainstay of treatment , especially for large lesions or where differentiation from a malignant lesion is difficult is surgical drainage with or without excision . in concordance with other case reports we would like to point out that percutaneous drainage under ultrasonography guidance of bilateral suprarenal abscess has good response . early diagnosis and early nonsurgical treatment may lead to a successful outcome with decreased incidence of unnecessary laparotomy . Output:	neonatal adrenal abscess is a rare condition . bilateral adrenal abscess are extremely rare . we present this case focusing on the usefulness of needle aspiration under ultrasonographic guidance . the bilateral suprarenal cystic masses are identified by ultrasonography and different sequences of magnetic resonance imaging .
PubmedSumm118876	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: type 2 diabetes mellitus ( t2 dm ) is a major public health burden that poses management challenges in clinical practice.1 the core pathophysiology of t2 dm has been attributed to the classic triad of decreased insulin secretion , increased insulin resistance , and elevated hepatic glucose production . research has shown that additional mechanisms , including those related to the fat cell ( accelerated lipolysis ) , gastrointestinal tract ( incretin deficiency / resistance ) , -cell ( hyperglucagonemia ) , kidney ( increased glucose reabsorption ) , and the brain ( insulin resistance ) , referred to as the ominous octet,2 are also involved . overt t2 dm occurs only when -cells fail ( due to decreased mass or their failure to recognize the hyperglycemic signal ) and can no longer compensate for the increased insulin secretion required to maintain normoglycemia.3 amelioration of the decline in -cell function must be addressed to alter the progressive nature of the disease.4,5 agents that may prevent deterioration of -cell function or enhance endogenous insulin concentrations are much needed for the management of t2 dm . other pathophysiologic defects of t2 dm that current therapeutic agents do not address include hyperglucagonemia , accelerated gastric emptying , and decrease or loss of the incretin effect . it had been demonstrated that glucagon secretion in t2 dm is not suppressed after a carbohydrate - rich meal.6,7 this results in an inability to suppress postprandial hepatic glucose production and excessive plasma glucose excursions . the rate of gastric emptying is a key determinant of postprandial glucose excursions and is often accelerated in people with diabetes.8,9 in t2 dm , glucagon - like peptide-1 ( glp-1 ) concentrations are reduced in response to a meal , whereas glucose - dependent insulinotropic polypeptide concentrations are normal or increased . this observation suggests resistance to the actions of glucose - dependent insulinotropic polypeptide , making glp-1 the favored potential therapeutic target.10,11 many of the pathophysiologic disturbances that are present in t2 dm can be corrected by incretin replacement with glp-1 . in response to the physiologic loss of incretin activity associated with t2 dm , administration of exogenous glp-1 has been shown to lower both fasting and postprandial plasma glucose significantly.12,13 the main limitation in developing glp-1 for the treatment of t2 dm is its short half - life of less than two minutes . by removing two n - terminal amino acids , dipeptidyl peptidase-4 ( dpp-4 ) rapidly inactivates glp-1.14 the development of the glp-1 receptor agonists offers incretin - based therapies with built - in modifications to provide resistance to dpp-4 degradation . liraglutide ( victoza ; novo nordisk inc , bagsvaerd , denmark ) is a modified form of human glp-1 ( -lglutamyl [ n--hexadenoyl]-lys,26 arg34-glp-1 [ 737 ] ) . native glp-1 is a 30-amino acid peptide produced by cleavage of the transcription product of the preproglucagon gene.15 liraglutide was obtained by substitution of lysine 34 to arginine near the nh2 terminus , and by addition of a c16 fatty acid at the - amino group of lysine ( at position 26 ) using a -glutamic acid spacer , which allows noncovalent binding to albumin ( see figure 1).16 the resultant molecule shares 97% ( 36/37 amino acids ) sequence identity with native human glp-1.17 the high degree of homology of liraglutide to glp-1 may in part explain the relatively low levels of antibodies produced in response to liraglutide . pharmacokinetic studies show that liraglutide , after subcutaneous injection , has a time to maximum plasma concentration ( tmax ) of 913 hours and a half - life ( t1/2 ) of 13 hours . indeed , following subcutaneous injection , the fatty acid chain allows liraglutide to self - associate and form heptamers at the injection site depot . it is thought that the size of the heptamer and strong self - association are the most likely mechanisms by which delayed absorption of liraglutide from the subcutis is facilitated . 18 once in the bloodstream , the fatty acid chain allows reversible binding to serum albumin , providing partial stability and resistance to metabolism by ddp-4 and reduces renal clearance , giving liraglutide a protracted mechanism of action.19 liraglutide metabolism does not depend on one single organ for its elimination . about 89%100% of intact liraglutide is present in plasma , with only two minor metabolites and no intact liraglutide detected in urine or feces,17 suggesting slow degradation into small peptides , amino acids , and fatty acid fragments eliminated through the liver or the kidney.20,21 to evaluate the effect of hepatic impairment on the pharmacokinetic properties of liraglutide , six patients with normal hepatic function and 18 patients with mild , moderate , or severe hepatic impairment received a single dose of subcutaneous liraglutide 0.75 mg.22 liraglutide bioavailability appeared to decrease with an increasing degree of hepatic impairment , with no significant differences in the safety parameters between the two groups . the effect of injection site ( abdomen , upper arm , and thigh ) on the pharmacokinetic profile of liraglutide was investigated.23 it was found that based on the area under the concentration - time curve ( auc ) , the abdomen and thigh were equivalent . although tmax and t1/2 were similar between the injection sites , maximum concentration ( cmax ) was lower in the thigh than in the abdomen . based on these results , the differences in bioavailability were not considered clinically relevant , and the three injection sites can be used interchangeably . age and gender pharmacokinetic equivalence of subcutaneous liraglutide 1 mg / day demonstrated that when adjusted for body weight , similarity was confirmed between young and elderly subjects , and no significant effect of gender was observed.24 liraglutide delays gastric emptying and could affect the absorption pattern of concomitant drugs . the effect of subcutaneous liraglutide 1.8 mg on the pharmacokinetic properties of atorvastatin 40 mg , griseofulvin 500 mg , lisinopril 20 mg , and digoxin 1 mg was evaluated in healthy subjects.25 the aucs of griseofulvin and atorvastatin were equivalent in liraglutide - treated and placebo - treated subjects . on the other hand , the aucs of lisinopril and digoxin were decreased by 15% and 16% , respectively . the cmax for atorvastatin , digoxin , and lisinopril was decreased and for griseofulvin was increased . tmax for atorvastatin , digoxin , and lisinopril was also delayed , confirming a liraglutide - induced shift in absorption kinetics . a similar study assessing the effects on acetaminophen after exposure to liraglutide23 also demonstrated lower cmax and delayed tmax compared with placebo . one of the first large single - center , randomized , double - blind , sequential dose escalation ( 1.25 to 20.0 g / kg single dose ) study of 64 healthy nondiabetic men confirmed that liraglutide has a pharmacokinetic profile that is consistent with once - daily administration ( tmax 912 hours after dosing and t1/2 1115 hours).26 absorption of liraglutide was slow , with cmax achieved between 9 and 12 hours after dosing . a frequently sampled intravenous glucose tolerance test ( ivgtt ) was performed and showed a statistically significant increase in insulin secretion ( p = 0.0002 ) , but there was no significant effect on glucagon levels . no significant effect was observed on glucose levels during the ivgtt , but there was a dose - dependent increase in the glucose disappearance constant . there were no reports of serious adverse events and all subjects completed the study . a higher number of adverse events were reported in subjects in active treatment versus placebo treatment , such as headache , dizziness , nausea , and vomiting . whereas headache and dizziness occurred at the majority of dose levels , nausea and vomiting mainly occurred at 1015 g / kg . there was a tendency toward lower urine volumes at doses 12.5 g / kg , but there was no overall significant difference in urine volumes 024 hours after dose administration between active and placebo treatment . another study in 30 healthy men with consecutive dose levels of liraglutide ( 1.2512.5 g / kg)19 showed similar results . there were dose - proportional increases in exposure ( auc and cmax ) with increasing doses . overall , there was a higher frequency of adverse events in the active - treated patients than in the placebo - treated subjects . three subjects were withdrawn due to adverse events , dizziness , fever and pharyngitis , and nausea and diarrhea . combined urine volume data showed a statistically significant reduction following a dose of liraglutide compared with placebo . in a dose - finding study in 24 healthy japanese men who received three consecutive dose levels of liraglutide ( 1525 g / kg ) , the daily pharmacokinetic profiles after receiving the last dose showed dose - dependent increases in the auc at 024 hours , cmax , and minimum concentration . elimination rate constant , volume of distribution , and clearance were not affected by dose.27 a similar profile was found when the drug was administered to t2 dm patients once daily as a subcutaneous injection for one week.28 relatively high plasma concentrations of liraglutide were maintained throughout the 24-hour dosing period , demonstrating that once - daily administration of liraglutide should be sufficient . liraglutide has demonstrated glucose - dependent insulin secretion , improvements in -cell function , deceleration of gastric emptying , and promotion of early satiety leading to weight loss.29 the effects of liraglutide on -cells in vitro and in animal models were of particular interest . when mice with diabetes mellitus ( db / db mice ) were exposed to liraglutide , a significantly increased -cell mass ( p < 0.05 ) and -cell proliferation rate ( p < 0.001 ) were observed versus placebo exposure.30 the effect of liraglutide on -cell mass was also noted in zucker diabetic fatty rats.31 after six weeks of treatment , a higher total -cell mass was observed in zucker diabetic fatty rats treated with liraglutide than in those in the placebo group ( p < 0.03 ) . when normoglycemia was maintained in these animals , this may suggest that the influence of glp-1 agonism on -cell mass dynamics in vivo may depend on the glycemic state . liraglutide was significantly better than native glp-1 in inhibiting apoptosis in cells treated with either agent . particularly , liraglutide was able to inhibit cytokine - induced apoptosis in primary rat islet cells in a dose - dependent manner , and to reduce free fatty acid - induced apoptosis by approximately 50%.32 furthermore , a recent study investigated the efficacy of liraglutide to prevent or delay diabetes in uc davis t2 dm rats , a model of polygenic obese t2dm.33 liraglutide treatment delayed diabetes onset by 4.1 0.8 months compared with control ( p < 0.0001 ) and by 1.3 0.8 months compared with energy - restricted animals ( p < 0.05 ) . energy restriction and liraglutide treatment lowered fasting plasma glucose and glycosylated hemoglobin ( hba1c ) compared with control . liraglutide - treated animals demonstrated lower fasting plasma insulin , glucagon , and triglycerides compared with both control and energy - restricted animals . additionally , energy - restricted and liraglutide - treated animals exhibited more normal islet morphology . the effect of a single subcutaneous dose of liraglutide 10 g / kg on glycemic control was assessed in patients with t2dm.34 liraglutide significantly reduced fasting plasma glucose compared with placebo ( 6.9 1.0 versus 8.1 1.0 mmol / l , p < 0.01 ) . in another study , subcutaneous liraglutide 0.6 mg once daily35 improved fasting plasma glucose , and this effect was significant after the first week and persisted through eight weeks of treatment ( p = 0.002 versus placebo ) . there was also a significant decrease in hba1c levels compared with placebo ( 0.80% , p = 0.028 ) . liraglutide caused a moderate delay in the postprandial rate of gastric emptying and reduced the rate at which postprandial plasma glucose appeared in the circulation . a study in patients with t2 dm showed that liraglutide increased -cell function in the fasting state by 30% , by homeostasis model assessment for function ( homa - b).28 the maximum -cell secretory capacity was significantly higher after treatment with liraglutide compared with placebo , and the proinsulin - to - insulin ratio was reduced by 40%50% , an additional indication of improved -cell function . this resulted in a significant reduction by approximately 20% in 24-hour glucose auc and postprandial glucose after liraglutide injection . with liraglutide , insulin concentrations were significantly higher after an intravenous glucose bolus ( first - phase insulin secretion , a 60% increase ) and during steady - state hyperglycemia ( second - phase insulin secretion , a 240% increase).36 patients with t2 dm were randomized to treatment with liraglutide 0.65 , 1.25 , or 1.9 mg / day or placebo to evaluate insulin secretion.37 after 14 weeks , first - phase insulin secretion ( measured by ivgtt ) was significantly increased at the two highest doses of liraglutide by 118% and 103% , respectively . second - phase insulin secretion was significantly increased only in the 1.25 mg / day group versus placebo . arginine - stimulated insulin secretion during a hyperglycemic clamp test also increased significantly at the two highest dose levels versus placebo , by 114% and 94% , respectively . it has been demonstrated that treatment with liraglutide , at a dose of 1.8 mg daily , significantly decreased the mean energy intake by 18% during an ad libitum meal ( ~850 kj).38 a modest effect on appetite sensation has also been reported . a significant 58 mmhg reduction in systolic blood pressure with different doses of liraglutide was seen , with no change in diastolic blood pressure . 39 a meta - analysis of three large pooled - data studies with liraglutide showed a significant 2.74.5 mmhg reduction in systolic blood pressure.40 finally , treatment with liraglutide may have positive effects on plasma glucagon secretion , and does not impair the counterregulatory glucagon response to hypoglycemia in patients with t2dm.41 however , other studies26,36,44 failed to reproduce these findings . encouraging preclinical and phase i clinical pharmacology results with liraglutide led to larger phase ii trials in patients with t2 dm , demonstrating that liraglutide is effective and well tolerated , both in monotherapy and in combination with oral antidiabetic drugs . in a 12-week , double - blind , randomized , placebo - controlled trial with an open - label sulfonylurea comparator in 190 patients with t2 dm , five fixed dosage groups of liraglutide were tested ( 0.045 , 0.225 , 0.45 , 0.60 , or 0.75 mg).42 treatment with the two highest dose of liraglutide reduced hba1c significantly more than placebo ( 0.70% , p = 0.0002 , and 0.75% , p < 0.0001 , respectively ) . fifty - nine percent of patients completing the trial in the two highest dosage groups achieved hba1c 7% . in the 0.45 mg liraglutide dosage group , a statistically significant decrease in body weight ( p = 0.0184 ) compared with placebo was noted . mean -cell function ( measured by homa ) was significantly higher in the 0.75 mg liraglutide group than in the placebo group ( p = 0.0002 ) . the proinsulin - to - insulin ratio decrease was statistically significant after treatment with 0.75 mg of liraglutide compared with placebo ( p = 0.0244 ) . of the 135 patients exposed to liraglutide , one in the 0.60 mg group experienced minor hypoglycemia . the number of patients with adverse events was comparable across the liraglutide groups and the placebo group . for gastrointestinal events ( nausea ) , the incidence seemed to increase with increasing doses of liraglutide . another 12-week , randomized , multicenter study compared the same five doses of liraglutide with metformin.43 hba1c was maintained at a relatively stable level during treatment in the metformin group and in the 0.45 mg , 0.6 mg , and 0.75 mg liraglutide groups . after 12 weeks , patients in the metformin group had a slight weight loss of 0.61% ( p = 0.124 versus baseline ) , whereas the five liraglutide groups has a weight loss ranging from 0.05% ( 0.045 mg , p = 0.825 versus baseline ) to 1.87% ( 0.225 mg , p = 0.006 , versus baseline ) . all treatment groups , except for the lowest dose , showed a decrease in total body mass and total fat mass ( measured by dual - energy x - ray absorptiometry scan ) . the study demonstrated , except for the lowest liraglutide dose group , an increase in fasting serum insulin levels , with greater increases observed in the 0.75 mg dosage group ; the same dosage group showed an increase in c - peptide levels that were significantly different from the metformin group ( p = 0.002 ) . the proportion of patients reporting adverse events with liraglutide treatment ( 52%68% ) was comparable with those treated with metformin ( 56% ) . the most frequent adverse event was injection site bruising , constipation , and diarrhea in the liraglutide group . the frequency of injection site bruising was not different between the liraglutide groups ( 5.7% ) and the metformin group ( 5.9% ) , which only received placebo injection , indicating that bruising was most likely caused by the injection , rather than the trial medication . nauck et al44 evaluated 144 t2 dm patients on metformin treatment in a five - week study where patients were randomized to receive metformin plus liraglutide , liraglutide or metformin , or metformin plus glimepiride ( open - label ) . the dose of liraglutide in the study was increased weekly from 0.5 mg to 2 mg . adding on liraglutide to existing metformin therapy resulted in a 3.9 mmol / l decrease in fasting plasma glucose in favor of liraglutide treatment ( p < 0.0001 ) , whereas switching subjects from metformin to liraglutide monotherapy gave an additional 1.4 mmol / l reduction ( p = 0.011 ) . hba1c lowered after treatment with metformin plus liraglutide compared with metformin alone ( 0.8% , p < 0.001 ) . -cell function ( measured by homa ) was significantly increased for metformin plus liraglutide versus metformin plus glimepiride ( 13.0% , p = 0.014 ) , and for liraglutide versus metformin therapy ( 28.7% , p < 0.0001 ) . liraglutide monotherapy increased homa compared with metformin therapy ( 3.3% , p = 0.0001 ) . after treatment , body weight had significantly decreased from baseline by 2.2 kg and 2.1 kg in the groups receiving liraglutide combination and monotherapy , respectively , and significantly by 1.7 kg on metformin monotherapy , with a significant difference in body weight reduction between the metformin plus liraglutide group compared with metformin plus glimepiride group ( 2.9 kg , p < 0.0001 ) . the study was double - blind , randomized , and placebo - controlled using three doses of liraglutide ( 0.65 , 1.25 , or 1.90 mg ) . after 14 weeks of treatment , the hba1c changes in the liraglutide groups compared with placebo were 1.74% , p < 0.0001 ; 1.69% , p < 0.0001 ; and 1.27% , p < 0.0001 , for the 1.90 , 1.25 , and 0.65 mg doses , respectively . the proportion of patients reaching hba1c < 7% was 46% ( 1.90 mg ) , 48% ( 1.25 mg ) , 38% ( 0.65 mg ) , and 5% ( placebo ) in the four groups . glycemic control was associated with a decrease in body weight in all treatment groups , with a maximum estimated weight loss of 2.99 kg in the 1.90 mg liraglutide group ( p = 0.0390 ) . the median change from baseline in proinsulin - to - insulin ratio was significant for all three liraglutide groups versus placebo ( p = 0.0111 , p = 0.0062 , and p = 0.0218 for the 1.90 , 1.25 , and 0.65 mg doses , respectively ) . in addition , there was a significant lowering in fasting glucagon concentrations in the 1.90 mg liraglutide group compared with placebo ( p = 0.0497 ) . systolic blood pressure decreased significantly in all treatment groups compared with placebo ( 7.9 mmhg , p = 0.0023 ; 5.2 mmhg , p = 0.0417 ; 7.4 mmhg , p = 0.0041 in the 1.90 , 1.25 , and 0.65 mg groups , respectively ) , but the drop of 23 mmhg in the diastolic blood pressure in all groups was not statistically significant . lipid parameters were also measured , but only triglyceride levels decreased compared with placebo ( 22% , p = 0.0110 ; 15% , p = 0.0854 ; 19% , p = 0.0303 in the 1.90 , 1.25 , and 0.65 mg groups , respectively ) . the proportions of patients reporting a gastrointestinal adverse event were 37% , 29% , 38% , and 23% of patients treated with liraglutide 1.90 mg , 1.25 mg , 0.65 mg , and placebo , respectively , with a higher event rate reported at the highest dose in the comparison with placebo ( p < 0.05 ) . only four of 123 liraglutide - treated patients withdrew from the study because of gastrointestinal adverse events . there were no treatment - related effects on induction of antibodies and no thyroid ultrasonographic changes . there were no clinically relevant changes reported in vital signs , electrocardiographic parameters , physical examination , or safety laboratory parameters ( hematology , biochemistry , and urinalysis ) in any of the above studies.39,4244 the first comparison between liraglutide and a ddp-4 inhibitor was in a parallel - group , open - label , multicenter trial , in which 658 patients with t2 dm with inadequate glycemic control ( hba1c 7.5%10% ) on metformin were randomized to receive 1.2 mg or 1.8 mg of subcutaneous liraglutide once daily , or 100 mg oral sitagliptin once daily for 26 weeks.45 mean decreases in hba1c from baseline were 1.50% for 1.8 mg liraglutide , 1.24% for 1.2 mg liraglutide , and 0.90% for sitagliptin ( p < 0.0001 between both the liraglutide and sitagliptin groups ) . mean decreases in fasting plasma glucose were 2.14 mmol / l for 1.8 mg liraglutide , 1.87 mmol / l for 1.2 mg liraglutide , and 0.83 mmol / l for sitagliptin ( p < 0.0001 between both the liraglutide and sitagliptin groups ) . mean weight loss was 3.38 kg for 1.8 mg liraglutide , 2.86 kg for 1.2 mg liraglutide , and 0.96 kg for sitagliptin ( p < 0.0001 between both the liraglutide and sitagliptin groups ) . in assessment of -cell function by homa , c - peptide concentration , and proinsulin - to - insulin ratio , both liraglutide doses were associated with improvement compared with sitagliptin . changes in the lipid profile between liraglutide and sitagliptin were not significant , except for total cholesterol reduction that was greater with liraglutide 1.8 mg compared with sitagliptin ( p = 0.0332 ) . when comparing with sitagliptin , liraglutide 1.8 mg and 1.2 mg caused a higher proportion of nausea , but this was transient ( ~13 days ) . one patient on liraglutide 1.2 mg had a major hypoglycemic episode ( 3.6 mmol / l ) . one thyroid problem ( reported as a formation in the thyroid gland ) in a patient on 1.2 mg liraglutide was classified as a serious adverse event , but histology showed no signs of malignancy . no pancreatitis was reported . in view of a weight benefit from treatment with liraglutide compared with other antidiabetic drugs , a study in obese individuals without t2 dm using higher doses of liraglutide was performed.46 obese subjects ( body mass index 3040 kg / m ) were randomly assigned to receive liraglutide ( 1.2 mg , 1.8 mg , 2.4 mg , or 3.0 mg by subcutaneous injection once a day ) , placebo ( also subcutaneously ) , or orlistat ( 120 mg three times a day orally ) . the trial was therefore masked for liraglutide or placebo treatment ( but not the dose ) , and open - label for orlistat treatment . the estimated mean weight loss in the intention - to - treat population from randomization to week 20 was significantly greater with liraglutide at all doses than with placebo ( 2.8 kg ) , and was dose - dependent ( 4.8 kg , 5.5 kg , 6.3 kg , 7.2 kg , for 1.2 mg , 1.8 mg , 2.4 mg , and 3.0 mg doses , respectively ) . sixty - one percent of individuals in the liraglutide treatment groups lost more than 5% of their baseline weight , which was significantly more than that in the placebo group ( p 0.0001 ) . furthermore , more individuals treated with liraglutide 3.0 mg lost more than 5% baseline weight than those treated with orlistat ( 76% versus 44% , p < 0.0001 ) . the proportion of patients with metabolic syndrome at week 20 decreased by more than 60% in those treated with liraglutide 2.4 mg and 3.0 mg mean hba1c in individuals treated with liraglutide was slightly reduced compared with that in individuals on placebo and orlistat at week 20 ; the reduction seemed to be dose - dependent , ranging from 0.14% in the 1.2 mg group to 0.24% in the 3.0 mg dose group . median -cell function ( as assessed by homa ) decreased on placebo and orlistat treatment by 17% and 21% , respectively , but increased on liraglutide treatment by 5%24% . the most common adverse events with liraglutide were nausea and vomiting , which occurred seven times more frequently with liraglutide 2.4 mg and 3.0 mg than with placebo . this was mostly transient and of mild or moderate intensity , and the frequency increased with dose . most nausea events ( 80% ) developed within the first four weeks of the trial during dose titration . psychiatric disorders ( insomnia , depressed mood , nervousness ) were slightly more frequent in subjects treated with liraglutide 2.4 mg and 3.0 mg than in those on placebo . finally , a comprehensive phase iii evaluation consisting of six randomized clinical trials was developed . the lead ( liraglutide effect and action in diabetes ) program involved 6500 subjects seen at 600 sites in 41 countries worldwide , of whom 4445 received liraglutide . the aim of these trials was to evaluate the efficacy and safety of liraglutide as monotherapy and in combination with other antidiabetic drugs and insulin ( see table 1 ) . lead 147 was a 26-week , five - arm randomized trial testing the effect of three doses of liraglutide ( 0.6 , 1.2 , and 1.8 mg ) added to glimepiride 4 mg / day in comparison with the same dose of glimepiride in combination with placebo or rosiglitazone 4 mg / day . at the end of the study , hba1c levels were significantly more reduced in all liraglutide groups ( 0.6% , 1.08% , and 1.13% for the 0.6 , 1.2 , and 1.8 mg doses , respectively ) than with the placebo ( + 0.23% ) or rosiglitazone ( 0.44% ) groups ( p < 0.0001 ) . the estimated proportion of subjects treated with either liraglutide 1.2 mg or 1.8 mg reaching hba1c target was substantially greater compared with either placebo ( p < 0.0001 ) or rosiglitazone ( p 0.0003 ) , with more patients reaching hba1c < 7.0% with liraglutide 1.8 mg compared with 1.2 mg ( p = 0.018 ) . all doses of liraglutide decreased fasting plasma glucose more than did placebo ( p < 0.0001 ) , while only liraglutide 1.2 mg or 1.8 mg produced greater reductions than rosiglitazone . changes in body weight were minor in all liraglutide and placebo groups , compared with the 2.1 kg increase in the rosiglitazone group . reductions in the proinsulin - to - insulin ratio were greater with both liraglutide 1.2 mg and 1.8 mg compared with either rosiglitazone or placebo ( p 0.02 ) . homa ( -cell function ) increased with liraglutide ( 1.8 mg or 1.2 mg ) compared with rosiglitazone ( p < 0.05 ) , while this increase was only different from placebo with liraglutide 1.2 mg ( p = 0.01 ) . lead 248 was a 26-week , placebo - controlled , double - blind , five - arm , randomized trial testing the effect of three doses of liraglutide ( 0.6 , 1.2 , and 1.8 mg ) added to metformin 1 g twice daily as compared with the same dose of metformin in combination with placebo or glimepiride 4 mg / day . in comparison with placebo , hba1c levels decreased significantly more with liraglutide 0.6 mg ( 0.8% ) , 1.2 mg ( 1.1% ) , and 1.8 mg ( 1.1% ) . the hba1c target ( 7.0% ) was achieved by significantly more subjects in the 1.8 mg liraglutide group than in the 1.2 mg liraglutide group ( 42.4% versus 35.3% , p = 0.0265 ) . the decreases in fasting plasma glucose from baseline for the liraglutide groups ( 1.1 , 1.6 , and 1.7 mmol / l for 0.6 , 1.2 , and 1.8 mg , respectively ) were significantly greater than the increase observed for the placebo group ( + 0.4 mmol / l , p < 0.0001 ) , but were similar to the decrease observed for the glimepiride group ( 1.3 weight loss was dose - dependent in the liraglutide treatment groups ( 1.8 0.2 , 2.6 0.2 , and 2.8 0.2 kg for 0.6 , 1.2 , and 1.8 mg , respectively ) and was significantly different ( p < 0.0001 ) from the weight gain in the glimepiride group ( 1.0 0.2 kg ) . weight losses in the 1.2 mg and 1.8 mg liraglutide groups were also significantly greater ( p 0.01 ) than the weight loss in the placebo group ( 1.5 0.3 kg ) . decreases in the proinsulin - to - insulin ratio from baseline for the liraglutide groups were comparable with those in the glimepiride group and were significantly different ( p < 0.0001 ) from those in the placebo group . the liraglutide groups had improvements in homa ( -cell function ) of 63 , 70 , and 71% for the 0.6 , 1.2 , and 1.8 mg liraglutide groups , respectively . the 1.2 mg and 1.8 mg liraglutide groups had significant reductions in systolic blood pressure of 23 mmhg compared with an increase of 0.4 mmhg observed in the glimepiride group ( treatment difference compared with glimepiride : 1.2 mg liraglutide , 3.2 mmhg , p = 0.0128 ; 1.8 mg liraglutide , 2.7 mmhg , p = 0.0467 ) . an extension of the lead 2 trial with an 18-month open - label period where all patients were maintained on their randomized therapy was done to investigate treatment satisfaction obtained using a validated questionnaire.49 all the liraglutide groups showed improved overall satisfaction from baseline , which was significantly greater than for metformin ( p < 0.05 ) , but comparable with glimepiride in combination with metformin . all the liraglutide groups were more satisfied with their current treatment and more likely to continue versus the metformin group after 26 and 78 weeks ( p < 0.05 ) . moreover , the liraglutide 1.2 mg and 1.8 mg groups were more likely to recommend to others versus the metformin group ( p < 0.05 ) . lead 350 was a 52-week randomized trial comparing liraglutide ( 0.8 , 1.2 , 1.8 mg ) and glimepiride 8 mg / day . in comparison with glimepiride , hba1c levels decreased significantly more with liraglutide 1.2 mg ( 0.33% , p = 0.0014 ) and 1.8 mg ( 0.62% , p < 0.0001 ) . the reduction with liraglutide 1.8 mg was significantly greater than that with 1.2 mg ( 0.29% , p = 0.0046 ) . participants previously treated with diet and exercise had greater decreases in hba1c than did those who switched from an oral antidiabetic drug to liraglutide . at the end of the study , 28% of participants treated with liraglutide 1.2 mg and 38% treated with liraglutide 1.8 mg reached the target hba1c of 6.5% or less , compared with 16% in those on glimepiride ( p = 0.0025 and p < 0.001 for liraglutide 1.2 mg and 1.8 mg , respectively ) . overall , compared with 28% in the glimepiride group , 43% of participants treated with liraglutide 1.2 mg ( p = 0.0007 ) and 51% on liraglutide 1.8 mg ( a greater proportion of participants in the liraglutide groups achieved the fasting plasma glucose target ( 5.07.2 mmol / l ) than in the glimepiride group ( 37.6% and 41.4% versus 22.2% for liraglutide 1.2 mg and 1.8 mg versus glimepiride group , respectively , p 0.0001 ) . treatment with liraglutide was also associated with weight loss , whereas the glimepiride group presented weight gain . insulin resistance ( measured by homa ) was reduced by 0.65% in the liraglutide 1.2 mg group and 1.35% in the 1.8 mg group , but increased in the glimepiride group ( p = 0.0249 and p = 0.0011 for liraglutide 1.2 mg and 1.8 mg , respectively ) . the proinsulin - to - insulin ratio and -cell function showed no significant differences between treatments . the double - blind period was followed by an open - label , two - year extension , involving 73% of the patients who had completed the one - year follow - up . results showed that the greater benefit of liraglutide on metabolic control and body weight as compared with glimepiride was maintained after two years , with a lower risk of hypoglycemia.51 patient - reported outcome assessments were performed as part of the lead 3 trial.52 the battery of scales compromised 77 self - administered questions . patient weight assessment was more favorable with liraglutide 1.8 mg ( p = 0.002 ) , and 52% were less likely to feel overweight . mean weight concerns were less with liraglutide than with glimepiride ( p < 0.0001 and p < 0.001 for 1.2 and 1.8 mg liraglutide , respectively ) . mean mental and emotional health and general perceived health assessments improved more with liraglutide 1.8 mg than with glimepiride ( p = 0.012 and p = 0.033 , respectively ) . lead 453 was a 26-week , placebo - controlled , doubleblind , randomized , parallel - group trial testing the effect of two doses of liraglutide ( 1.2 and 1.8 mg ) added to metformin 1 g twice daily and rosiglitazone 4 mg / day compared with the same dose of metformin and rosiglitazone in combination with placebo . mean hba1c levels decreased significantly more in the liraglutide groups than in the placebo group ( 0.9% and 1.1% for liraglutide 1.2 and 1.8 mg , respectively , p < 0.0001 ) . at the end of the study , 57.5% and 53.7% of subjects in the 1.2 and 1.8 mg liraglutide groups , respectively , had an hba1c < 7% , compared with 28.1% in the placebo group , with 37.3% and 36.2% , respectively , reaching hba1c of 6.5% compared with 14.4% on placebo . the decreases in fasting plasma glucose from baseline for the liraglutide groups ( 2.2 mmol / l and 2.4 mmol / l for 1.2 mg and 1.8 mg liraglutide , respectively ) were significantly greater than the decrease observed in the placebo group ( 0.4 mmol / l , p < 0.0001 ) . weight loss was observed in the liraglutide - treated groups ( 1.0 0.3 and 2.0 0.3 kg from baseline for 1.2 mg and 1.8 mg liraglutide , respectively ) , and was significantly different ( p < 0.0001 ) from the weight gain in the placebo group ( 0.6 0.3 kg ) . the weight loss in the 1.8 mg liraglutide group was significantly greater than in the 1.2 mg liraglutide group ( p = 0.011 ) . the 1.2 and 1.8 mg liraglutide groups had significant reductions in mean systolic blood pressure compared with the placebo group ( 1.2 mg liraglutide p < 0.0001 ; 1.8 mg liraglutide p = 0.0009 ) . minor but statistically significant increases in pulse rate were observed in the liraglutide - treated groups versus placebo ( p = 0.0071 and p = 0.0001 , respectively , for 1.2 mg and 1.8 mg ) . the decrease in the proinsulin - to - insulin ratio and increase in c - peptide concentration from baseline for the liraglutide groups were significant ( p < 0.05 for both ) compared with the placebo group . both liraglutide treatment groups had significant improvement in -cell function ( p < 0.0001 for both groups versus placebo ) . insulin resistance ( measured by homa ) was reduced in all three treatment groups , but was not significantly different between groups . lead 554 was a 26-week , randomized , placebo - controlled , double - blind , parallel - group trial testing the effect of 1.8 mg of liraglutide added to metformin 1 g twice daily plus glimepiride 24 mg / day in comparison with the same dose of metformin and glimepiride with placebo or insulin glargine . after 26 weeks of treatment , the hba1c reduction from baseline with liraglutide was 1.33% , 0.24% with placebo , and 1.09% with insulin glargine ( treatment differences for liraglutide versus placebo ( 1.09% , p < 0.0001 and liraglutide versus insulin glargine 0.24% , p = 0.0015 ) . the reduction in mean fasting plasma glucose in the liraglutide group , and the likelihood of achieving targets ( 57.2 mmol / l ) was significantly superior compared with the placebo group ( p < 0.0001 ) but not versus the insulin glargine group . the mean weight loss from baseline of 1.8 kg achieved in the liraglutide group was significantly superior to that in the placebo group ( weight difference of 1.39 kg , p = 0.0001 ) . weight increased by 1.6 kg with insulin glargine , resulting in a mean treatment difference of 3.43 kg , p < 0.0001 . overall , weight loss was independent of nausea , although in the very small number of patients with sustained nausea , there seemed to be a greater weight loss ( 3.2 kg ) . the proinsulin - to - c - peptide ratio showed a significant improvement in the liraglutide group compared with the insulin glargine group ( p = 0.0019 ) and the placebo group ( p < 0.0001 ) . a significant reduction in systolic blood pressure was observed with liraglutide ( 4.0 mmhg ) compared with insulin glargine ( 0.54 mmhg increase ; treatment difference 4.51 mmhg , p = 0.0001 ) , but not in comparison with placebo . blonde and russell - jones summarized the safety of liraglutide during lead 15 studies.55 throughout the trials , liraglutide was generally well tolerated ; most adverse events reported were mild to moderate in severity . gastrointestinal events were most frequently reported with liraglutide monotherapy and combination therapy and were often dose - related ; 29.3% of patients receiving 1.8 mg liraglutide reported nausea . however , this symptom tended to decrease in frequency after four weeks in each trial . serious adverse events were uncommon . in the lead 5 trial , patients treated with insulin glargine or placebo reported a 7% frequency of serious adverse events in comparison with 4% on liraglutide therapy . as monotherapy , no major hypoglycemia incidents were reported , and 8% of patients treated with liraglutide 1.8 mg reported minor hypoglycemia ( plasma glucose < 3.1 mmol / l ) . only one major hypoglycemic episode ( blood glucose = 3.0 the proportion of subjects experiencing minor hypoglycemia across a 26-week treatment period with liraglutide 1.8 mg in combination with glimepiride was 8.1% , significantly greater than the proportion of subjects on rosiglitazone in combination with glimepiride ( 4.3% , p = 0.0065 ) . the incidence of minor hypoglycemia was lower when liraglutide was used in combination with metformin ( ~3% ) . antibodies to liraglutide were found in 9%13% of subjects treated with liraglutide in the lead 1study ; 4.1% and 6.7% of subjects treated with 1.2 and 1.8 mg liraglutide , respectively , at the end of lead 4 ; and in 9.8% of patients in the liraglutide group in lead 5 . no significant differences in calcitonin levels were found between the liraglutide groups and comparators in the lead 2 , 3 , and 5 studies . there was a significant increase in calcitonin levels for the 1.2 mg liraglutide group versus placebo group ( p = 0.022 ) , but not with the 1.8 mg liraglutide group in the lead 4 study ( although all levels were in the normal range).47,48,50,53,54 lead 6 was the first study that compared two glp-1 analogs . 56 this was a 26-week , randomized , open - label trial testing the effect of liraglutide 1.8 mg once daily versus exenatide 10 g twice daily in combination with metformin 1 g twice daily and/or glimepiride 24 mg / day . patients treated with liraglutide showed a reduction in hba1c of 1.12% , compared with a reduction of 0.79% in the exenatide group ( p < 0.0001 ) , and more patients achieved an hba1c < 7% in the liraglutide group ( 54% versus 43% , respectively , p = 0.0015 ) . mmol / l versus 0.60 mmol / l of exenatide , p < 0.0001 ) . increases in fasting plasma insulin ( p = 0.0355 ) and -cell function ( p < treatment differences for fasting c - peptide and proinsulin - to - insulin ratio were not significant . reduction of triglyceride ( p = 0.0485 ) and free fatty acid ( p = 0.014 ) values were significantly greater in the liraglutide group than in the exenatide group . despite an overall lower reporting of adverse events in the liraglutide group than the exenatide group , the liraglutide group had more serious ( 5.1% versus 2.6% ) and severe ( 7.2% versus 4.7% ) adverse events . the most frequent severe adverse events were dyspepsia in the liraglutide group and nausea in the exenatide group . although the incidence of nausea was similar initially , it was less persistent with liraglutide . the proportion of patients who had minor hypoglycemia was lower with liraglutide than with exenatide ( 26% versus 34% , respectively ) . heart rates increased slightly in both treatment groups , but were significantly greater for liraglutide ( p = 0.0012 ) . after 26 weeks , patients continued into a nonrandomized 14-week extension;57 all exenatide patients were switched to liraglutide 0.6 mg then escalated to 1.8 mg . mean hba1c further decreased from 7.2% at week 26 to 6.9% at week 40 ( p < 0.0001 ) after switching from exenatide to liraglutide , but remained similar with continued liraglutide ( 7.0%6.9% ) . further reductions in fasting plasma glucose , body weight , and systolic blood pressure ( all p < 0.0001 ) occurred , while the homa ( -cell function ) increased ( p = 0.0001 ) after switching from exenatide to liraglutide . in patients continuing liraglutide , reductions in fasting plasma glucose ( p = 0.0973 ) , body weight ( p = 0.0089 ) , and systolic blood pressure ( p = 0.0128 ) occurred . nausea and diarrhea occurred in 3.2% of patients switching from exenatide to liraglutide and in 1.5% of those continuing liraglutide . calcitonin levels remained at the lower level of the normal range and did not differ between the groups . in a two - year mouse and rat carcinogenicity study , liraglutide resulted in treatment - related proliferative changes in c - cells of the thyroid gland . these changes ranged from focal hyperplasia to benign and malignant neoplasia , and were dose - dependent.58 the clinical relevance of this finding is unknown . moreover , five cases of papillary thyroid carcinoma have been reported in clinical trials in patients treated with liraglutide compared with one case in a comparator treatment group.59 according to novo nordisk,60 because of the uncertain relevance of the rodent c - cell tumor findings in humans , liraglutide should be prescribed only to patients for whom the potential benefits are considered to outweigh the potential risks . liraglutide is contraindicated in patients with a personal or family history of medullary thyroid carcinoma and in patients with multiple endocrine neoplasia syndrome type 2 . based on the findings in rodents , monitoring with serum calcitonin or thyroid ultrasound was performed during clinical trials , but this may have increased the number of unnecessary thyroid surgeries . liraglutide appears to be associated with a risk of acute pancreatitis , with seven cases in 3900 patients receiving liraglutide versus one case in a patient taking another diabetic drug.61 all liraglutide trials have demonstrated a consistent and sustained reduction in hba1c and fasting plasma glucose when the drug was used as monotherapy or added to other antidiabetic therapy . the advantages are its incretin effect , and the convenience of once - daily injection . the presence of antibodies was observed , but there were no indications in any of the liraglutide studies that antibody formation compromised efficacy . liraglutide will acquire an important role , not only in t2 dm treatment , but also in preservation of -cell function , if the data thus far are confirmed by long - term studies and post - marketing surveillance . furthermore , the reduction in hba1c associated with the beneficial effects of liraglutide in insulin resistance , systolic blood pressure , and weight loss , as shown by the lead studies , could represent a significant probability of prevention of diabetic complications and may reduce atherosclerotic cardiovascular events . Output:	the pathophysiology of type 2 diabetes has been attributed to the classic triad of decreased insulin secretion , increased insulin resistance , and elevated hepatic glucose production . research has shown additional mechanisms , including incretin deficiency or resistance in the gastrointestinal tract . liraglutide is a modified form of human glucagon - like peptide-1 . liraglutide was obtained by substitution of lysine 34 for arginine near the nh2 terminus , and by addition of a c16 fatty acid at the - amino group of lysine ( at position 26 ) using a -glutamic acid spacer . liraglutide has demonstrated glucose - dependent insulin secretion , improvements in -cell function , deceleration of gastric emptying , and promotion of early satiety leading to weight loss . liraglutide has the potential to acquire an important role , not only in the treatment of type 2 diabetes , but also in preservation of -cell function , weight loss , and prevention of chronic diabetic complications .
PubmedSumm118877	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: early identification of alzheimer s disease ( ad ) is needed to facilitate timely treatment delivery and to improve quality of life for affected patients and their families.1 cholinergic deficit is present early in the course of ad2,3 and is a likely contributor to the earliest clinical manifestations of this illness , including declarative memory impairments2,3 and disturbances of preattentive information filtering ( ie , impaired auditory sensory gating).4,5 the latter of these impairments reflects cholinergic deficit - related abnormal hippocampal physiology , disturbances of which are amenable to identification using the functional magnetic resonance imaging ( fmri ) auditory sensory gating paradigm . first described by tregellas et al,6 this brief and behaviorally passive fmri paradigm interrogates the functional integrity of the cholinergically dependent hippocampal frontal information processing network involved in auditory sensory gating.6,7 diminished availability or action of acetylcholine to the hippocampus impairs the ability of this structure to perform its inhibitory ( ie , information filtering ) function in this network . this cholinergic deficit - induced failure of inhibitory function is the putative neurobiological basis for the increased blood oxygen level - dependent ( bold ) signal ( ie , excessive activation ) in the hippocampus that is evoked by the auditory sensory gating paradigm.6 the fmri auditory sensory gating paradigm therefore might be a viable method by which to identify ad - induced , cholinergic deficit - mediated , hippocampal dysfunction . the primary aim of this proof - of - concept study was to assess the feasibility of evaluating auditory sensory gating among persons with ad with this fmri paradigm . a secondary and exploratory aim was a preliminary test of the hypothesis that the fmri auditory sensory gating paradigm evokes greater activation ( ie , identifies failed inhibitory function ) of the hippocampus in ad subjects when compared with healthy comparison subjects . only decisionally capable subjects with ad were eligible for study participation , and informed consent was obtained from all study participants . subjects were included if clinical interview , neuropsychiatric examination , and medical records review established a diagnosis of probable ad by the national institute for neurological and communicative disorders and stroke - alzheimer s disease and related disorder association ( ninds - adrda ) criteria.8 subjects were assessed cognitively using the mini - mental status examination ( mmse),9 frontal assessment battery ( fab),10 and alzheimer s disease assessment scale - cognitive subscale ( adas - cog).11 mmse z - scores12 2 were required for a diagnosis of probable ad . subjects with focal neurological deficits , parkinsonism , a hachinski ischemic scale13 score > 4 , neurodevelopmental , substance use , and psychiatric disorders and those taking cognitively impairing medications were excluded . data from healthy adults studied previously in the laboratory of one of the investigators ( jrt ) were used to develop a convenience comparison sample for the mri analyses . studies were performed with a 3 t ge mri system ( ge healthcare , milwaukee , wi , usa ) using a standard quadrature head coil . imaging parameters were followed as described by tregellas et al,6 as was administration of the fmri sensory gating paradigm . briefly , subjects were administered a hearing test in the scanner to set the task volume at 50 db above the hearing threshold . the paradigm used a clustered volume acquisition approach to allow a 6-sec silent period following scanner noise for neuronal inhibitory circuitry to reset and allow auditory stimuli to be presented during silence . during the 12-sec period between scanner noise , subjects heard 4 sec of 1 ) silence , 2 ) one click , or 3 ) multiple ( repeated ) clicks with a 0.5-sec interclick interval . the following volume was acquired 46 sec after auditory stimulation to capture peak hemodynamic response . five blocks of each stimulus type were randomly distributed throughout each run . between runs , the contrast repeated clicks one click was the measure of auditory sensory gating . this subtraction removes most of the effects of overall auditory responsiveness , which was measured separately in the contrast one click silence. multiple clicks , rather than a click pair , were used to maximize sensitivity to the difference in bold response between the two stimulus conditions . the fmri analyses were performed using statistical parametric mapping software version 5 ( spm5 ; wellcome trust centre for neuroimaging , london , uk ; http://www.fil.ion.ucl.ac.uk/spm/software/spm5/ ) and used a region of interest ( roi ) approach . data from each subject were realigned to the first volume , normalized to the montreal neurological institute gray - matter template , using a gray - matter - segmented ir - epi as an intermediate to improve registration , and smoothed with 8-mm fwhm gaussian kernel . data were modeled with an hrf - convolved boxcar function , using the general linear model in spm5 . a 128-sec high - pass filter was applied to remove low - frequency fluctuation in the bold signal . the roi was an 8-mm sphere centered at x = 24 , y = 18 , and z = 15 , the hippocampal location that showed maximal group differences in a previous study using the sensory gating task.6 data within the roi were small volume corrected at a family - wise error rate of p < 0.05 . subjects were included if clinical interview , neuropsychiatric examination , and medical records review established a diagnosis of probable ad by the national institute for neurological and communicative disorders and stroke - alzheimer s disease and related disorder association ( ninds - adrda ) criteria.8 subjects were assessed cognitively using the mini - mental status examination ( mmse),9 frontal assessment battery ( fab),10 and alzheimer s disease assessment scale - cognitive subscale ( adas - cog).11 mmse z - scores12 2 were required for a diagnosis of probable ad . subjects with focal neurological deficits , parkinsonism , a hachinski ischemic scale13 score > 4 , neurodevelopmental , substance use , and psychiatric disorders and those taking cognitively impairing medications were excluded . data from healthy adults studied previously in the laboratory of one of the investigators ( jrt ) were used to develop a convenience comparison sample for the mri analyses . studies were performed with a 3 t ge mri system ( ge healthcare , milwaukee , wi , usa ) using a standard quadrature head coil . imaging parameters were followed as described by tregellas et al,6 as was administration of the fmri sensory gating paradigm . briefly , subjects were administered a hearing test in the scanner to set the task volume at 50 db above the hearing threshold . the paradigm used a clustered volume acquisition approach to allow a 6-sec silent period following scanner noise for neuronal inhibitory circuitry to reset and allow auditory stimuli to be presented during silence . during the 12-sec period between scanner noise , subjects heard 4 sec of 1 ) silence , 2 ) one click , or 3 ) multiple ( repeated ) clicks with a 0.5-sec interclick interval . the following volume was acquired 46 sec after auditory stimulation to capture peak hemodynamic response . five blocks of each stimulus type were randomly distributed throughout each run . between runs , the contrast repeated clicks one click was the measure of auditory sensory gating . this subtraction removes most of the effects of overall auditory responsiveness , which was measured separately in the contrast one click silence. multiple clicks , rather than a click pair , were used to maximize sensitivity to the difference in bold response between the two stimulus conditions . the fmri analyses were performed using statistical parametric mapping software version 5 ( spm5 ; wellcome trust centre for neuroimaging , london , uk ; http://www.fil.ion.ucl.ac.uk/spm/software/spm5/ ) and used a region of interest ( roi ) approach . data from each subject were realigned to the first volume , normalized to the montreal neurological institute gray - matter template , using a gray - matter - segmented ir - epi as an intermediate to improve registration , and smoothed with 8-mm fwhm gaussian kernel . data were modeled with an hrf - convolved boxcar function , using the general linear model in spm5 . a 128-sec high - pass filter was applied to remove low - frequency fluctuation in the bold signal . the roi was an 8-mm sphere centered at x = 24 , y = 18 , and z = 15 , the hippocampal location that showed maximal group differences in a previous study using the sensory gating task.6 data within the roi were small volume corrected at a family - wise error rate of p < 0.05 . two individuals satisfying ninds - adrda criteria for ad were imaged using the fmri auditory sensory gating paradigm . the first was a 71-year - old , right - handed man with a 6-year history of probable ad who was on stable treatment with donepezil 10 mg daily and memantine 10 mg twice daily . his mmse was 24/30 ( z = 2.5 ) , fab was 11/18 , and adas - cog was 22/70 . the second was a 78-year - old , right - handed woman with a 7-year history of probable ad who was on stable treatment with donepezil 10 mg daily and memantine 5 mg twice daily . her mmse was 22/30 ( z = 3.8 ) , fab was 11/18 , and adas - cog was 34/70 . clinical examination and assessment of functional status ( obtained by caregiver interview ) classified ad severity in both subjects as mild . both subjects tolerated the imaging procedure easily , remained alert ( per visual monitoring of subjects during scanning by our research assistant ) , and yielded fmri data of quality sufficient to subject those data to analyses . the convenience comparison sample consisted of four healthy subjects drawn from prior studies in our laboratory . as the mean age of the ad group was significantly older ( 74.5 4.9 ; p < 0.001 ) , age was used as a covariate in the fmri data analyses . consistent with our a priori hypothesis , subjects with ad demonstrated abnormal activation of the hippocampus ( t = 3.61 ; see figure 1 ) . single - subject bold responses at the hippocampal local maxima , expressed as percent signal change relative to the global mean , are presented in figure 2 . the fmri auditory sensory gating paradigm appears to be a feasible method of evaluating the preattentive information - filtering function of the cholinergically dependent hippocampally mediated auditory sensory gating network among persons with ad . in respect of its potential practicality , the fmri auditory sensory gating paradigm assesses hippocampal function in a single , relatively brief , mr imaging session ; such brevity is an important feature for the practical application of fmri assessments in the ad population . additionally , it assesses hippocampal function using a passive protocol ; the only in - scanner behavioral requirement of persons with ad is to remain awake . as dementia due to ad entails difficulty learning new information and executing complex tasks , imaging paradigms that interrogate hippocampal function by passive means , like ours and that of others,14 offer potential practical advantages over those that require subjects to learn and perform novel inscanner cognitive tasks.1518 the unimodal imaging approach employed here also offers potential feasibility advantages over others that , although robust , may be relatively more time and resource intensive in respect of data acquisition and analyses.14,19,20 additionally , the emphasis on hippocampal function rather than structure is an important feature of this approach , given the variable relationship between hippocampal structure and clinical symptoms in the early stages of ad.3,2124 the preliminary analysis of the fmri data obtained during this demonstration project identif ied greater bold signal in the hippocampus of the two ad subjects when compared with healthy comparison subjects , even after correcting for the between - group age difference . this observation is consistent with our predicted effects of ad neuropathology on the neurobiology of auditory sensory gating . the single - subject bold responses at the hippocampal local maxima identified in the between - group comparison presented in figure 2 are also noteworthy in that there is no overlap between the ad and healthy comparison subjects . as a proof - of - concept exercise , these data are encouraging of the possibility that , with further development , bold responses during the fmri auditory sensory gating paradigm might contribute usefully to the research and/or clinical assessments of persons with late - life cognitive impairments . the preliminary nature of this study , however , necessitates cautious interpretation of these findings and suggestions . replication of this work in a larger sample of subjects with ad and age- and gender - matched healthy comparison subjects is required to evaluate the usefulness of this fmri protocol as a method of identifying ad - induced hippocampal dysfunction . given the preponderance of women affected by this condition and previously observed sexual dimorphism in cerebral responses to fmri - related auditory stressors,18 the possibility of sexual dimorphism in bold responses in the fmri auditory sensory gating paradigm requires consideration and investigation . additionally , studies are needed to determine whether this paradigm distinguishes individuals with ad from individuals with memory impairment due to other common late - life neuropsychiatric conditions , especially dementias caused by other forms of neurodegeneration and/or cerebrovascular disease . it is also important to note that sensory gating impairments are not specific to ad but are instead features of a wide range of neuropsychiatric conditions , most notably schizophrenia6,25 and traumatic brain injury.7 a common theme across these conditions is cholinergic dysfunction . loss of ventral forebrain neurons and their cortical efferents in ad2,3 and traumatic brain injury2628 and ( maladaptive ) mutation of alpha-7 nicotinic cholinergic receptors in schizophrenia25 are the putative bases for auditory sensory gating impairments in these conditions . it is possible that the fmri auditory sensory gating paradigm will be understood most usefully as an assessment of the integrity of this system independent of clinical diagnosis . if so , then it may not be a marker of early ad per se but instead a marker of any condition in which cholinergic dysfunction occurs , whether by loss of cholinergic neurons , injury to their axons , or altered responsiveness to acetylcholine at their cortical targets . increased bold responses observed in older patients during the fmri auditory sensory gating paradigm might only narrow the range of potential etiologic explanations for cognitive complaints to those conditions in which cholinergic dysfunction figures prominently ( ie , ad , amnestic mild cognitive impairment , diffuse lewy body disease , traumatic brain injury , and , possibly , cerebrovascular disease).29 if such studies demonstrate that this method is useful for any of these purposes at the group and single - patient levels , then the timing and economic implications of its introduction into the diagnostic evaluation of persons with suspected ad will also need to be considered . for the present , this initial proof - of - concept demonstration is encouraging of the potential usefulness of the fmri auditory sensory gating paradigm in ad research . the present findings suggest that further development and investigation of this neuroimaging technique are warranted . Output:	cholinergic deficits are an early and functionally significant manifestation of alzheimer s disease ( ad ) . these deficits contribute to impairment of hippocampally mediated information processing , including declarative memory impairments and abnormal auditory sensory gating . a functional imaging technique that facilitates identification of changes in cholinergically dependent hippocampal information processing would be of considerable use in the study and clinical evaluation of persons with this condition . techniques that interrogate hippocampal function passively , ie , in a manner requiring no cognitive effort or novel task learning during the neuroimaging procedure , would also be especially useful in this cognitively impaired population . the functional magnetic resonance imaging sensory gating paradigm developed at the university of colorado , co , usa , is a functional neuroimaging technique that possesses both of these characteristics . we developed a demonstration project using this paradigm in which we passively interrogated hippocampal function in two subjects with probable ad of mild severity . imaging data were quick and easy in these subjects and served usefully as an initial demonstration of the feasibility of using this neuroimaging method in this population . preliminary analyses of the data obtained from these subjects identified abnormal blood oxygen level - dependent responses when compared with four healthy comparators , and the pattern of these responses was consistent with impaired function of the auditory sensory gating network . the strengths and limitations of this neuroimaging paradigm and the additional issues that require investigation in order to continue its development into a research and clinical technique for use in this population are discussed .
PubmedSumm118878	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: the prevalence of type 2 diabetes has increased , and type 2 diabetes is now one of the main threats to human health . it is known that environmental factors , especially lifestyle , are associated with the risk of diabetes and that adequate lifestyle intervention can reduce the incidence of diabetes . although several risk factors for type 2 diabetes have been identified , most of them were identified on the basis of studies in western populations . the effect of the risk factors should be evaluated for the japanese population , because there are genetic and environmental differences between the two populations . in 2010 , the japan diabetes society ( jds ) released a new diagnostic criteria for diabetes mellitus that included the use of hemoglobin a1c ( hba1c ) as a diagnostic tool for diabetes mellitus and a single examination of hba1c 6.5% alone being used to define diabetes mellitus in epidemiological studies . although there are several drawbacks to making a diagnosis of diabetes based on hba1c values , it is quite appealing for epidemiological studies , because no glucose tolerance test or fasting blood sample is required , detecting chronic hyperglycemia by a single measurement , and there is a low risk of misclassification , which is a result of low variability of hba1c . the aim of the present study was to evaluate risk factors for type 2 diabetes in a japanese population . the present study was based on the diabetes research carried out in a large cohort study in japan , the japan public health centerbased prospective study ( jphc study ) , an ongoing , longitudinal cohort study investigating cancer , cardiovascular diseases and other lifestylerelated diseases . the jphc study population consists of all registered japanese inhabitants of the public health center areas who were aged 4059 years in 1990 ( cohort i ) and 4069 years in 1993 ( cohort ii ) . the jphc diabetes study , which consisted of the measurement of hba1c , and an additional questionnaire about diabetes and lifestyle , was carried out at the time of health checkups and the subjects were the jphc participants who received a health checkup . written informed consent to participate in the diabetes study was obtained separately from the informed consent to the jphc study . the baseline survey of the diabetes study was carried out in 19981999 for cohort ii and in 2000 for cohort i , and the 5year followup survey was carried out in 20032004 and 2005 , respectively . as two public health center areas ( katsushika and kamigoto ) were excluded from the analysis in the present study , because different definitions of the study population were used in one area and because the followup survey was carried out 6 years after the baseline survey in the other area , the analysis in the present study was carried out on subjects in the remaining eight public health center areas ( four in cohort i and four in cohort ii ) . each participant completed a selfadministered questionnaire for the jphc study that included questions about previously diagnosed medical conditions , medication and lifestyle factors , such as physical activity , alcohol intake and smoking . the separate questionnaire regarding the diabetes study included questions about a detailed past history of diabetes , treatment of diabetes , family history of diabetes , walking and daily physical activity . of the 24743 subjects ( 9065 men and 15678 women ) who completed the baseline questionnaires , 11601 ( 3946 men and 7655 women ) completed the followup questionnaire . we excluded subjects who had any of the following conditions at baseline : cardiovascular disease , chronic liver disease , any type of cancer , or diabetes ( n = 1491 ) . we excluded subjects who had diabetes at baseline as subjects of the present study , because it was designed to investigate the incidence of diabetes . in the present study , individuals who had missing baseline data for any of the exposure parameters described later were also excluded ( n = 1154 ) . after the aforementioned exclusions , the remaining cohort consisted of 9223 subjects ( 3076 men and 6147 women ) . in the present study , diabetes was defined based on selfreport or a hba1c value of 6.5% or more in national glycohemoglobin standardization program equivalent value ( see the supporting information for details ) . those who did not have diabetes at baseline , but who had diabetes at the time of the 5year followup survey , were defined as incident cases of diabetes . coffee intake was assessed based on the consumption of cups of coffee and cans of coffee ( canned coffee is popular in japan ) separately by dividing it into the following categories : 12 days per week , 34 days per week , 56 days per week , 1 cup ( or can ) per day , 23 cups ( or cans ) per day , 46 cups ( or cans ) per day , 79 cups ( or cans ) per day and 10 or more cups ( or cans ) per day . physical activity was assessed on the basis of leisure time physical activity , daily physical activity and walking . leisure time physical activity was divided into two categories : active ( participate in sports at least once a week ) and inactive , as in the previous report . daily physical activity was classified into four levels : light , moderate , slightly heavy and heavy . walking was classified into the following four categories according to average number of hours walked per day : < 0.5 , 0.50.9 , 11.9 and 2 h or more . all analyses were carried out by using the data from the 9223 individuals ( 3076 men and 6147 women ) . we carried out multivariate logistic regression analysis to evaluate the contribution of the risk factors ( some of them are beneficial ) to diabetes incidence . as the primary objective of the present study was to examine the effect of established ( mainly in western countries ) risk factors of diabetes in the japanese population , the established risk factors for incidence of diabetes were selected as explanatory variables . alcohol intake was divided into the following four groups : nondrinker ( consume alcoholic beverage less than once a week ) and three groups of alcohol drinkers ( consume alcoholic beverage one or more times per week ) according to tertile of weekly ethanol intake . we included several risk factors , such as coffee intake , waking and daily physical activity , that were not included in the previous study . for each category of coffee intake , an average daily intake was assigned as follows : 0.2 for 12 days per week , 0.5 for 34 days per week and 0.75 for 56 days per week , 1 for 1 per day , 2.5 for 23 per day , 5 for 46 per day , 8 for 79 per day and 10 for 10 or more per day . total daily coffee intake was calculated by adding average daily intake from cups of coffee and double the average daily intake from cans of coffee based on the estimate that one can of coffee is the equivalent of two cups of coffee . then , total coffee intake was divided into four categories : less than one cup per day , 11.9 cups per day , 22.9 cups per day and 3 cups or more per day . risk factors of diabetes were evaluated by logistic regression as odds ratios adjusted for potential confounding factors including age ( 4655 , 5665 and 6675 years ) , body mass index ( quartiles ) , smoking status ( never smoker , past smoker or current smoker at < 20 or 20 cigarettes per day ) , alcohol intake , family history of diabetes ( at least one parent or one sibling with diabetes ) , leisure time physical activity , walking ( < 0.5 , 0.50.9 , 11.9 and 2 h or more ) , daily physical activity ( light , moderate , slightly heavy and heavy ) , hypertension ( defined as systolic blood pressure 140 mmhg or diastolic blood pressure 90 mmhg or being on medication for hypertension ) , coffee intake and baseline hba1c value . we analyzed cohorts i and ii together , because the results of separate analysis for cohorts i and ii did not differ largely . in the present study , diabetes was defined based on selfreport or a hba1c value of 6.5% or more in national glycohemoglobin standardization program equivalent value ( see the supporting information for details ) . those who did not have diabetes at baseline , but who had diabetes at the time of the 5year followup survey , were defined as incident cases of diabetes . coffee intake was assessed based on the consumption of cups of coffee and cans of coffee ( canned coffee is popular in japan ) separately by dividing it into the following categories : 12 days per week , 34 days per week , 56 days per week , 1 cup ( or can ) per day , 23 cups ( or cans ) per day , 46 cups ( or cans ) per day , 79 cups ( or cans ) per day and 10 or more cups ( or cans ) per day . physical activity was assessed on the basis of leisure time physical activity , daily physical activity and walking . leisure time physical activity was divided into two categories : active ( participate in sports at least once a week ) and inactive , as in the previous report . daily physical activity was classified into four levels : light , moderate , slightly heavy and heavy . walking was classified into the following four categories according to average number of hours walked per day : < 0.5 , 0.50.9 , 11.9 and 2 h or more . all analyses were carried out by using the data from the 9223 individuals ( 3076 men and 6147 women ) . we carried out multivariate logistic regression analysis to evaluate the contribution of the risk factors ( some of them are beneficial ) to diabetes incidence . as the primary objective of the present study was to examine the effect of established ( mainly in western countries ) risk factors of diabetes in the japanese population , the established risk factors for incidence of diabetes were selected as explanatory variables . alcohol intake was divided into the following four groups : nondrinker ( consume alcoholic beverage less than once a week ) and three groups of alcohol drinkers ( consume alcoholic beverage one or more times per week ) according to tertile of weekly ethanol intake . we included several risk factors , such as coffee intake , waking and daily physical activity , that were not included in the previous study . for each category of coffee intake , an average daily intake was assigned as follows : 0.2 for 12 days per week , 0.5 for 34 days per week and 0.75 for 56 days per week , 1 for 1 per day , 2.5 for 23 per day , 5 for 46 per day , 8 for 79 per day and 10 for 10 or more per day . total daily coffee intake was calculated by adding average daily intake from cups of coffee and double the average daily intake from cans of coffee based on the estimate that one can of coffee is the equivalent of two cups of coffee . then , total coffee intake was divided into four categories : less than one cup per day , 11.9 cups per day , 22.9 cups per day and 3 cups or more per day . risk factors of diabetes were evaluated by logistic regression as odds ratios adjusted for potential confounding factors including age ( 4655 , 5665 and 6675 years ) , body mass index ( quartiles ) , smoking status ( never smoker , past smoker or current smoker at < 20 or 20 cigarettes per day ) , alcohol intake , family history of diabetes ( at least one parent or one sibling with diabetes ) , leisure time physical activity , walking ( < 0.5 , 0.50.9 , 11.9 and 2 h or more ) , daily physical activity ( light , moderate , slightly heavy and heavy ) , hypertension ( defined as systolic blood pressure 140 mmhg or diastolic blood pressure 90 mmhg or being on medication for hypertension ) , coffee intake and baseline hba1c value . we analyzed cohorts i and ii together , because the results of separate analysis for cohorts i and ii did not differ largely . the baseline characteristics of the subjects of the analysis are shown in table 1 . during the 5year followup period , we documented 232 incident cases ( 7.5% ) of diabetes among the men and 286 cases ( 4.7% ) among the women . of the 518 incident cases of diabetes , 132 were diagnosed by selfreport alone , and 310 on the basis of the hba1c value alone , and 76 cases on the basis of both selfreport and hba1c value . * alcohol intake was divided into tertiles based on weekly ethanol intake ( 1st tertile , < 16 g / week for men and < 35.2 g / week for women ; 2nd tertile , 161321.9 g / week for men and 35.380.4 g / week for women ; 3rd tertile , 322 g / week for men and 80.5 g / week for women ) . the multivariateadjusted odds ratios for the incidences of diabetes mellitus are shown in table 2 . among the men , age , body mass index , smoking ( both past smoking and current smoking ) and family history of diabetes significantly increased the risk of diabetes . among the women , body mass index , family history of diabetes and hypertension significantly increased the risk of diabetes . although some factors became insignificant and others became significant , the results did not change markedly after being adjusted for the baseline hba1c values . walking , daily physical activity ( for men ) and coffee intake ( for women ) tended to decrease the risk of diabetes , but the odds ratios were not statistically significant . every 0.1% increase in baseline hba1c value increased the risk of diabetes by 1.36 among the men and by 1.52 among the women . * adjusted for age , body mass index , smoking status , alcohol intake , family history of diabetes , leisure time physical activity , walking , daily physical activity , hypertension and coffee intake . adjusted for variables listed above and baseline hemoglobin a1c ( hba1c ) value . body mass index was divided into quartiles ( 1st quartile , < 21.6 kg / m for men and < 21.5 kg / m for women ; 2nd quartile , 21.623.5 kg / m for men and 21.523.4 kg / m for women ; 3rd quartile , 23.625.4 kg / m for men and 23.525.5 kg / m for women ; 4th quartile , 25.5 kg / m for men and 25.6 kg / m for women ) . in the present study , we examined the effect of risk factors for diabetes , which were established in western populations , in a japanese population . although we reported such an evaluation previously , there was a major difference between the definition of diabetes in the two studies , which was selfreport and hba1c in the present study as opposed to selfreport alone in the previous study , in addition a difference in the followup period and study population . one of the main problems in the previous study was the relatively low sensitivity of selfreported diabetes . in the previous study , in fact , just 208 of the 518 incident cases of diabetes were diagnosed by selfreport in the present analysis . the previous study used the data obtained from a 1990 survey in cohort i as the baseline data , and followedup 10 years later , therefore the area , the ages of the subjects at baseline and followup period of the present study were also different from those of the previous study . despite these differences , however , the results were not very different ; that is , the established risk factors of age , body mass index and family history of diabetes increased the risk of diabetes in both studies . the effect of smoking was stronger in the present study , and although the reason for the difference is unclear , there are several possible explanations . as the baseline survey in the present study was carried out 5 or 10 years after the baseline survey in the previous study , the cumulative exposure of the smokers might have been greater in the present study . the effect of smoking became stronger with the duration of the smoking period and that might be why the effect of smoking was stronger in the current study . another possible explanation is the difference between the accuracy of selfreports of diabetes by smokers and by nonsmokers , that is , smokers are generally less healthconscious than nonsmokers , and the proportion of unrecognized diabetes among men in the incident cases of diabetes was in fact larger among the current smokers ( 60% ) than the nonsmokers ( 49% ) in the present study . we also examined the effect of walking , daily physical activity and coffee intake in the present study , because these have been regarded as factors that protect against diabetes . although their effects were not statistically significant , walking and coffee intake tended to reduce the risk of diabetes in both men and women , and daily physical activity tended to reduce the risk of diabetes in men , but not in women . the difference between the men and women the failure of the differences to reach the level of significance might be a result of the relatively small numbers of subjects or the limitation of our assessment of physical activity . a negative association between coffee intake and risk of type 2 diabetes has been reported in studies carried out on various populations and in various countries . as japanese people consume much less coffee than western people , the categorization of coffee intake was shifted to a small amount compared with studies in western countries . that might be the reason why the effect of coffee intake against diabetes did not become significant in the present study . we also found that the baseline hba1c value was a significant risk factor for diabetes mellitus , and the other risk factors had independent associations of baseline hba1c value . the finding that most of the risk factors have independent associations of baseline hba1c value is important , because some risk factors were correlated with the hba1c values and the risk associated with such factors might be attributable to confounding with baseline hba1c . for example , hba1c and age were correlated , and hba1c increased as age increased . however , because the risk associated with age did not change markedly and remained statistically significant after adjustment for baseline hba1c in the men , age increased the risk of diabetes for men independently of the baseline hba1c value . in contrast , the risk associated with age decreased after adjustment for baseline hba1c in women . although the risk associated with age in women was not significant before adjustment for baseline hba1c and this might come from the relatively small numbers of incident cases , the decrease in risk associated with age in women after adjustment of baseline hba1c suggests that the risk was mainly mediated by hba1c . this also holds in the case of body mass index in men , that is , the risk associated with body mass index in men was mainly mediated by hba1c . in the present study , we defined diabetes based on hba1c values . in 2010 , the jds released new diagnostic criteria and a single examination of hba1c 6.5% alone can be defined as diabetes mellitus in epidemiological studies . diagnosing diabetes based on hba1c values is quite appealing , especially for epidemiological studies , because no glucose tolerance test or fasting blood sample is required . in addition , chronic hyperglycemia , which is the characteristic of diabetes mellitus , can be detected by a single measurement by using hba1c . furthermore , because the variability of hba1c values is low compared with that of fasting plasma glucose or 2h plasma glucose values , the risk of misclassification is considered to be low . however , there are several problems with diagnosing diabetes based on hba1c value alone . aside from the standardization problem , hba1c values do not reflect the plasma glucose level of subjects with hemoglobinopathy or diseases that result in abnormal erythrocyte turnover , such as anemia or liver cirrhosis . however , these problems do not seem to have caused serious problems in the present study because ( i ) we excluded subjects with severe diseases , such as liver cirrhosis ; ( ii ) diabetes was diagnosed not only on the basis of the hba1c values , but selfreport as well ; and ( iii ) misclassification occurs only when a shift in hba1c as a result of hemoglobinopathy or disease crosses the threshold value , that is , the hba1c value shifts from 6.5% to < 6.5% or vice versa and therefore it is possible to misclassify subjects with hba1c values around 6.5% , but the number of subjects with values around the hba1c value was not large and the number of misclassified subjects are expected to be small . the main limitation of the current study was the relatively low proportion of subjects who participated in the followup survey ( 47% ) . this was a limitation that was attributable to the study design , because the subjects of the present study were voluntary participants in a health checkup and only a small proportion of subjects of the jphc study received the checkup ( 26.8% ) . however , the differences between the baseline characteristics ( including major risk factors for diabetes ) of the subjects who participated in followup study and those who did not were not large ( data not shown ) , and we do not think that the relatively low rate of participation in the followup survey introduced a large bias in the present study . another limitation was that the subjects of the present study were the participants of health checkups and , generally , health checkup participants were more health conscious compared with those who did not participate . therefore , it is not clear whether the results of the present study can be generalized to the whole population and further studies are needed to clarify this point . in conclusion , we evaluated risk factors for diabetes mellitus established in western populations in a japanese population defining diabetes based on the subjects hba1c values , and the results showed that the established risk factors for diabetes were also risk factors in a japanese population . Output:	abstractaims / introduction : although several risk factors for type 2 diabetes have been identified , most of them have been identified in studies on western populations , and they should be evaluated in a japanese population . in 2010 , new diagnostic criteria for diabetes mellitus using hemoglobin a1c ( hba1c ) were released and its use in epidemiological studies has many advantages . the aim of the present study was to evaluate risk factors for type 2 diabetes defined based on hba1c values in a japanese population.materials and methods : a total of 9223 subjects ( 3076 men and 6147 women ) were followed up for 5 years . diabetes was defined based on selfreport or hba1c value . risk factors for diabetes were evaluated as odds ratios adjusted for potential confounding factors by logistic regression.results : during the 5year followup period , we documented 518 incident cases of diabetes ( 232 men and 286 women ) . of the 518 incident cases , 310 cases were diagnosed by hba1c alone . among the men , age , smoking ( both past smoking and current smoking ) and family history of diabetes significantly increased the risk of diabetes . among the women , body mass index , family history of diabetes and hypertension significantly increased the risk of diabetes . these results did not change markedly after adjustment for the baseline hba1c values , and the baseline hba1c value itself was a significant risk factor for diabetes mellitus.conclusions : known risk factors for diabetes established in western populations also increased the risk of diabetes in a japanese population defined on the basis of hba1c values . ( j diabetes invest , doi : 10.1111/j.20401124.2011.00119.x , 2011 )
PubmedSumm118879	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: despite declining incidence of acute viral hepatitis in recent years , it remained the most common cause of chronic liver disease ( cld ) world - wide . globally , more than 350 million people are chronic carriers of hepatitis b virus ( hbv ) and up to 40% of these individuals may progress to cirrhosis , liver failure or hepatocellular carcinoma . many of the estimated 130 - 170 million people with chronic hepatitis c virus ( hcv ) infection may also progress to cirrhosis and hepatocellular carcinoma . due to the gradual course of disease , its morbidity and mortality is often underestimated . cld is the tenth cause of mortality in the united states and is responsible for 25,000 deaths annually . it is estimated about 40% of all clds in the united states is due to hcv infection . hcv - associated cirrhosis is the most common indication for orthotopic liver transplantation in adults . the centers for disease control ( cdc ) estimates that 8,000 - 13,000 deaths occur each year in the united states due to chronic hcv infection . a number of preventive measures for patients with cld have been recommended to improve quality - of - life , prevent the development of complications and improve overall survival . one of them is the prevention of hbv super - infection by hbv vaccination and is recommended for people at high risk of either exposure to or severe morbidity of hbv infection , such as patients with other cld , particularly chronic hepatitis c. in co - infection with chronic hbv and hcv , replicating hbv lowers the replication of hcv , but both independently enhance the severity of hepatitis and the risks of liver cirrhosis and hepatocellular carcinoma . these include the world health organization , the cdc and prevention , the national institutes of health , the veteran 's health administration , the american liver foundation and the advisory committee on immunization practices . the first hbv vaccine was produced by the inactivation and purification of hepatitis b surface antigen ( hbsag ) obtained from the plasma of chronic hbv carriers . this was replaced by the production of hbsag using recombinant deoxyribonucleic acid ( dna ) technology . all the studies have shown that available ribosomal deoxyribonucleic acid ( rdna ) hbv vaccines of 5 - 10% or more do not create an antibody response to the hbsag component present in these preparations ( non - responders ) or they respond poorly ( hypo - responders ) in individuals with healthy immune system . the definition of non - responsiveness and hypo - responsiveness , generally , is anti - hbs level less than 10 miu / ml and 100 miu / ml , respectively . several factors affect the antibody response to hbsag , including the site of injection , sex , advancing age , being overweight and immunodeficiency . available information suggests that the immunogenicity of the hbv vaccine is reduced in patients with clds and in liver transplant recipients , but is unimpaired in patients with fatty liver . testing for post - immunization antibody titers is not recommended ; exceptions include patients at increased risk for recurrent exposure . this includes health - care workers , patients on chronic hemodialysis , gay or bisexual men and sexual partners of carriers . some experts also test for post - immunization antibody titers in patients with clds , due to the high risk of severe infection in this subgroup . the study was designed as an open prospective trial to compare the immunogenicity of the recombinant hbv vaccine of 40 and 20 g in patients with chronic hcv infection . trial was performed in two out - patient clinics infectious department of research center of sedighe tahere and imam reza hepatitis clinic of isfahan city , iran , from may 2010 to february 2011 . blood sample was obtained to assess the anti - hbs concentration 1 month after the basic vaccine schedule was completed to determine the rate of non - responsiveness ( anti - hbs < 10 miu / ml ) , seroconversion ( anti - hbs between 10 and 99 miu / ml ) and seroprotection ( anti - hbs 100 miu / ml ) . criteria for inclusion were subjects between 18 and 65 years old with chronic hcv infection and negative serum markers for hbv infection . chronic hcv infection was defined based on positive hcv - ab and hcv - ribonucleic acid ( rna ) , in a patient without clinical or laboratory findings , indicating acute hepatitis ( jaundice , very high aminotransferases ) . the exclusion criteria were transplanted patients or those on waiting lists , dialysis therapy and chronic renal patients with gfr < 60 ml / min/1.73 m , hiv - positive patients , patients with neoplasias , immunosuppressed patients , pregnant women and alcoholic hepatitis or cirrhosis . individuals already immunized against hbv ( presence of anti - hbs ) were excluded too . hiv - ab was tested in all patients and also the control group and those with positive results were not recruited . alcoholic patient was considered in the study , if he / she did drink at least 40 g of alcohol / day ( males ) and 20 g / day ( females ) for at least 5 years . presence of chronic hepatitis or cirrhosis in proven hcv infected patients ( by hcv rna or recombinant immuno blot assay ( riba ) , was detected based on clinical , laboratory , ultrasonographic , endoscopic and histopathological findings . cirrhotic patients were sorted using the original classification proposed by child - turcotte and modified by pugh . all precipitants who did not match the exclusion criteria and had given written , informed consent were recruited . a total of 64 patients with chronic infection of hcv and 32 healthy volunteers , as a control group , were included in the study . healthy volunteers were chosen from newly arrived hospital staff who were not vaccinated against hbv and needed to be vaccinated before starting their job as medical staff . we did nt match the patients and the controls by sex , because sex is not an important factor in response to hbv vaccination . chronic hcv infected patient were randomized to two groups ( standard dose and a double dose groups ) , using a computerized randomization software . for all participants , body mass index ( bmi ) was calculated at the beginning of the study and the quantitative anti - hbs titer was checked . patients were also inquired about the high - risk behaviors such as drinking , smoking , iv abuse and history of tattooing and transfusion . the sample size was calculated by the formula : n = ( z1-2 + z)[p1(1 p1 ) + p2(1 p2)]/(p1 p2 ) hbv vaccine ( hepavax - gene ) that used in this study was a liquid containing highly purified , non - infectious particles of hbsag , produced by dna recombinant technology in hansenula polymorpha cells . recombinant dna hbv vaccine ( hepavax - gene ) with a standard dosage , 1 ml ( 20 g ) was administered to all healthy volunteers in the control group and 32 patients who were selected randomly from hcv infected group whereas the double dosage , 2 ml ( 40 g ) , was administered to 32 remaining hcv infected patients , intramuscularly in the deltoid muscle at three different times ( months 0 , 1 and 6 ) . local and systemic side - effects related to the vaccine were documented following the injection of each dose of vaccine . for data missing prevention , we called every participant 1 day before the scheduled time for vaccination or blood sampling . the spss statistical analysis package ( version 18 ) was used for all calculations . patient and control groups were compared in relation to continuous variables with an independent t - test for independent variables and chi - square test for categorical variables . for all these comparisons , level of significance was considered to be less than 5% . the study was designed as an open prospective trial to compare the immunogenicity of the recombinant hbv vaccine of 40 and 20 g in patients with chronic hcv infection . trial was performed in two out - patient clinics infectious department of research center of sedighe tahere and imam reza hepatitis clinic of isfahan city , iran , from may 2010 to february 2011 . blood sample was obtained to assess the anti - hbs concentration 1 month after the basic vaccine schedule was completed to determine the rate of non - responsiveness ( anti - hbs < 10 miu / ml ) , seroconversion ( anti - hbs between 10 and 99 miu / ml ) and seroprotection ( anti - hbs 100 miu / ml ) . criteria for inclusion were subjects between 18 and 65 years old with chronic hcv infection and negative serum markers for hbv infection . chronic hcv infection was defined based on positive hcv - ab and hcv - ribonucleic acid ( rna ) , in a patient without clinical or laboratory findings , indicating acute hepatitis ( jaundice , very high aminotransferases ) . the exclusion criteria were transplanted patients or those on waiting lists , dialysis therapy and chronic renal patients with gfr < 60 ml / min/1.73 m , hiv - positive patients , patients with neoplasias , immunosuppressed patients , pregnant women and alcoholic hepatitis or cirrhosis . individuals already immunized against hbv ( presence of anti - hbs ) were excluded too . hiv - ab was tested in all patients and also the control group and those with positive results were not recruited . alcoholic patient was considered in the study , if he / she did drink at least 40 g of alcohol / day ( males ) and 20 g / day ( females ) for at least 5 years . presence of chronic hepatitis or cirrhosis in proven hcv infected patients ( by hcv rna or recombinant immuno blot assay ( riba ) , was detected based on clinical , laboratory , ultrasonographic , endoscopic and histopathological findings . cirrhotic patients were sorted using the original classification proposed by child - turcotte and modified by pugh . all precipitants who did not match the exclusion criteria and had given written , informed consent were recruited . a total of 64 patients with chronic infection of hcv and 32 healthy volunteers , as a control group , were included in the study . healthy volunteers were chosen from newly arrived hospital staff who were not vaccinated against hbv and needed to be vaccinated before starting their job as medical staff . we did nt match the patients and the controls by sex , because sex is not an important factor in response to hbv vaccination . chronic hcv infected patient were randomized to two groups ( standard dose and a double dose groups ) , using a computerized randomization software . for all participants , body mass index ( bmi ) was calculated at the beginning of the study and the quantitative anti - hbs titer was checked . patients were also inquired about the high - risk behaviors such as drinking , smoking , iv abuse and history of tattooing and transfusion . the sample size was calculated by the formula : n = ( z1-2 + z)[p1(1 p1 ) + p2(1 p2)]/(p1 p2 ) hbv vaccine ( hepavax - gene ) that used in this study was a liquid containing highly purified , non - infectious particles of hbsag , produced by dna recombinant technology in hansenula polymorpha cells . recombinant dna hbv vaccine ( hepavax - gene ) with a standard dosage , 1 ml ( 20 g ) was administered to all healthy volunteers in the control group and 32 patients who were selected randomly from hcv infected group whereas the double dosage , 2 ml ( 40 g ) , was administered to 32 remaining hcv infected patients , intramuscularly in the deltoid muscle at three different times ( months 0 , 1 and 6 ) . local and systemic side - effects related to the vaccine were documented following the injection of each dose of vaccine . for data missing prevention , we called every participant 1 day before the scheduled time for vaccination or blood sampling . patient and control groups were compared in relation to continuous variables with an independent t - test for independent variables and chi - square test for categorical variables . for all these comparisons , level of significance was considered to be less than 5% . a total of 64 patients were eligible according to the inclusion criteria and divided into two equal groups , randomly ; 32 ones received standard dose vaccine and 32 patients received a double dose vaccine . baseline characteristics and relative frequencies of risk factors of all participants are showed in table 1 . the mean age of the entire group was 34.4 9.0 years ( range , 21 - 65 years ) . the mean age of patients in the standard dose and a double dose vaccine group was 33.8 9.6 and 33.7 9.1 years , respectively and 32.1 7.6 years in the healthy group . the variance analysis showed that the age of the control group was nt significantly different from the age of patients groups ( p = 0.45 , p = 0.18 for comparison to standard dose and a double dose groups , respectively ) . the majority of patients were male ( 90.6% ) and had high - risk behaviors such as smoking , intraravenous drug users ( ivdu ) and tattooing . it was not surprising that injection drug abuse was the most common identifiable risk factor of hcv infection in our study ( 75% ) . a total of 56 patients were hcv rna positive proven by pcr and viral genotype was obtained in 49 patients . sex , bmi and genotype had similar distribution in all groups ( p > 0.05 ) . on physical examination of patients , there was no significant abnormality such as icterus , hepatosplenomegaly , ascites and edema . iu / l ) and ast ( mean 36.5 18 ) were mildly elevated in most patients . alkaline phosphatase , prothrombin time and bloodcell count were normal and the platelet count was more than 100,000/l in all subjects . demographic characteristics and risk factors of participants administration of hbv vaccine with three - doses of 20 and 40 g protocols in two chronic hcv groups and 20 g in all healthy controls created 65.6% , 62.5% and 53.1% seroprotection rate , respectively . non - responsiveness was observed in 12.5% of patients with standard dose ( 20 g ) protocol , whereas there was no non - responder in patients with a double dose ( 40 g ) protocol and healthy control group . hypo - responsiveness ( seroconversion ) was detected in 30.0% , 37.5% and 29.5% of standard dose protocol , double dose protocol patients and healthy group , respectively . responsiveness rates and anti - hepatitis b surface antibody titers of all participants are shown in table 2 . responsiveness rates and anti - hbsab titers surprisingly , our results showed significant lower rate of seroprotection in the healthy group compared with hcv positive patients with the same dose protocol vaccination . . however , anti - hbs mean level had no significant difference among three groups ( p = 0.052 ) . pearson correlation test showed no correlation between age and anti - hbs mean level ( r = 0.07 , p = 0.52 ) . there was no correlation between bmi and anti - hbs mean level ( r = 0.03 , p = 0.77 ) it was 165.3 150 miu / ml in males and 92.5 56 miu / ml in females ( p = 0.04 ) . mean anti - hbs level in genotype 1 and 3 was 174.0 125 miu / ml and 151.3 120 miu / ml , respectively ( p = 0.52 ) . from 96 participants who completed the vaccination protocol , nine individuals ( 8.3% ) reported local adverse reactions ( pain at the site of injection and erythema ) after vaccination . neither severe systemic adverse reactions nor neurologic symptoms occurred in the follow - up period . a total of 64 patients were eligible according to the inclusion criteria and divided into two equal groups , randomly ; 32 ones received standard dose vaccine and 32 patients received a double dose vaccine . baseline characteristics and relative frequencies of risk factors of all participants are showed in table 1 . the mean age of the entire group was 34.4 9.0 years ( range , 21 - 65 years ) . the mean age of patients in the standard dose and a double dose vaccine group was 33.8 9.6 and 33.7 9.1 years , respectively and 32.1 7.6 years in the healthy group . the variance analysis showed that the age of the control group was nt significantly different from the age of patients groups ( p = 0.45 , p = 0.18 for comparison to standard dose and a double dose groups , respectively ) . the majority of patients were male ( 90.6% ) and had high - risk behaviors such as smoking , intraravenous drug users ( ivdu ) and tattooing . it was not surprising that injection drug abuse was the most common identifiable risk factor of hcv infection in our study ( 75% ) . a total of 56 patients were hcv rna positive proven by pcr and viral genotype was obtained in 49 patients . sex , bmi and genotype had similar distribution in all groups ( p > 0.05 ) . on physical examination of patients , there was no significant abnormality such as icterus , hepatosplenomegaly , ascites and edema . iu / l ) and ast ( mean 36.5 18 ) were mildly elevated in most patients . alkaline phosphatase , prothrombin time and bloodcell count were normal and the platelet count was more than 100,000/l in all subjects . administration of hbv vaccine with three - doses of 20 and 40 g protocols in two chronic hcv groups and 20 g in all healthy controls created 65.6% , 62.5% and 53.1% seroprotection rate , respectively . non - responsiveness was observed in 12.5% of patients with standard dose ( 20 g ) protocol , whereas there was no non - responder in patients with a double dose ( 40 g ) protocol and healthy control group . hypo - responsiveness ( seroconversion ) was detected in 30.0% , 37.5% and 29.5% of standard dose protocol , double dose protocol patients and healthy group , respectively . responsiveness rates and anti - hepatitis b surface antibody titers of all participants are shown in table 2 . responsiveness rates and anti - hbsab titers surprisingly , our results showed significant lower rate of seroprotection in the healthy group compared with hcv positive patients with the same dose protocol vaccination . conversely , non - responsiveness was lower in healthy groups ( p = 0.026 ) . however , anti - hbs mean level had no significant difference among three groups ( p = 0.052 ) . pearson correlation test showed no correlation between age and anti - hbs mean level ( r = 0.07 , p = 0.52 ) . there was no correlation between bmi and anti - hbs mean level ( r = 0.03 , p = 0.77 ) . it was 165.3 150 miu / ml in males and 92.5 56 miu / ml in females ( p = 0.04 ) . mean anti - hbs level in genotype 1 and 3 was 174.0 125 miu / ml and 151.3 120 miu / ml , respectively ( p = 0.52 ) . from 96 participants who completed the vaccination protocol , nine individuals ( 8.3% ) reported local adverse reactions ( pain at the site of injection and erythema ) after vaccination . neither severe systemic adverse reactions nor neurologic symptoms occurred in the follow - up period . mild local reaction that occurred in 8.3% of precipitants in this study was similar to another study ( 7% of vaccines ) . shaw et al . reported extremely rare neurologic adverse events that did not exceed the incidence of that in the general population except the guillain - barre syndrome that occurred more frequently than expected ( 9 cases vs. 3.6 , respectively ) in follow - up of more than 850,000 vaccines in the united states . there is no doubt that the development of hbv vaccines is a major accomplishment in modern medicine . dual - infection with chronic hbv and hcv enhances the severity of hepatitis and the risks of liver cirrhosis and hepatocellular carcinoma and response to treatment is lower . literatures suggest that the immunogenicity of the hbv vaccine is reduced in patients with clds in 2004 , mattos et al . in a prospective study of 85 patients with chronic hcv infection and 46 healthy adults , reported non - response rate of 45 and 2% to three - dose regimen of the recombinant hbv vaccine in patients and control group , respectively . earlier studies showed the response rates in hcv infected patients varying between 69% and 100% . impaired immunogenicity has been described in patients with alcoholic liver disease , liver transplant recipients and in those awaiting liver transplantation . a randomized , double - blind trial in 110 alcoholic patients was conducted to assess whether the use of high - dose versus standard - dose hbv vaccine would be more effective . patients were randomly assigned to 20 g at baseline , 1 and 6 months versus 40 g at baseline , 1 , 2 and 6 months . seroconversion rates were improved in the high - dose arm ( 46 vs. 75% , respectively ) . in our study , non - responsiveness to three - dose ( 20 g ) regimen of the recombinant hbv vaccine , observed in 12.5% of 32 patients with chronic hcv infection versus 0.0% of 32 healthy control group . this was slightly more than expected response in the normal population ( 5 - 10% ) reported in other studies . although with a three - doubling dose ( 40 g ) regimen in other 32 chronic hcv patients , non - response rate was the same as that of healthy control group ( 0.0% ) . several factors may affect the antibody response to hbsag components in hbv vaccine . overall , according to the findings in this study and given the fact that the antibody response simply was divided into three groups of non - response , hypo - response and seroprotection , we may fail to appropriately decide about the borderline responses . there were four non - responders ( 12.5% ) in chronic hcv infected patients with standard dose vaccination compared with 100% response rate in double dose vaccination group . we conclude that using double dose vaccination in these patients is an effective way to increase the response rate . Output:	background : hepatitis b virus ( hbv ) vaccination is a well - known , safe and effective way for protection against hbv infection ; however , non - responders remain susceptible to infection with hbv . this is so important in patients with any kind of chronic liver disease , especially chronic hepatitis c virus ( hcv ) patients in whom acute hbv infection may lead to decompensation of liver disease . some of the studies have shown that immunogenicity of hbv vaccination is decreased in these patients . the aim of this study was to evaluate the efficacy and safety of double dose vaccination of hbv in these patients , compared with standard dose vaccination in similar patients and healthy adults.methods:a total of 64 patients with chronic hcv infection were randomized into 2 groups of 32 . group a received standard dose hbv vaccine , at 0 , 1 , 6 months , whereas group b received double dose hbv vaccine . group c consisted of 32 healthy adults who also received standard dose vaccination . at 1 month after the end of vaccination , hepatitis b surface antibody ( hbsab ) titer was checked in all participants and the results were compared.results:there was no significant difference in age or sex among three groups . the response rate in groups b and c was 100% ( all had hbsab titer > 10 miu / ml ) , while in group a , 4 patients ( 12.5% ) were non - responders ( hbsab titer < 10 miu / ml ) . the difference in response rate was statistically significant between group a and the other two groups ( p < 0.05).conclusions : the efficacy of standard dose hbv vaccination in patients with chronic hcv infection was suboptimal . using double dose vaccination in these patients was an effective way to increase the antibody response .
PubmedSumm118880	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: hypertension is not only a major risk factor for stroke and heart failure ( hf ) , but more importantly for coronary heart disease ( chd ) . based on the blood pressure ( bp ) cutoff of 140/90 mm hg for hypertension , as defined by the seventh report of the joint national committee on prevention , detection , evaluation , and treatment of high blood pressure ( jnc 7 ) , over 65 million adult americans , or approximately one fourth of the american population , have hypertension . the report of the interheart study involving 52 countries all over the world showed that hypertension conferred a greater adjusted relative risk of acute myocardial infarction than diabetes . among individuals aged 40 to 90 years , each 20/10 mm hg rise in bp doubles the risk of fatal coronary events . reports of national surveys conducted in various countries in north america , asia , and africa indicate that hypertension is highly prevalent , but poorly treated and/or controlled . this observation may be one reason while chd remains the leading cause of death and disability in the developed countries and is projected to be the leading cause of death in the developing world by 2020 [ 79 ] . hypertension accelerates the development and progression of atherosclerosis , and sustained elevation of bp can destabilize vascular lesions and precipitate acute coronary events . these cvs risks attributed to hypertension can be greatly reduced by optimal control of bp . although several antihypertensive agents exist , the optimal choice of agents and the appropriate target bp for patients with chd remain controversial . the goals of treating patients with hypertension and chd are to lower bp , reduce ischemia , and prevent cvs events . in this succinct paper , we examine the epidemiological evidence and the pathophysiological mechanisms for the linkage between hypertension and chd and we discuss the treatment options and the goals of therapy that are consistent with the recommendations of jnc 7 and american heart association ( aha ) scientific statement [ 1 , 10 ] . as more data from hypertension trials become available , we anticipate changes in the recommendations of the forthcoming jnc 8 . the pathophysiological link between hypertension and chd can be described under two major pathways as described below and shown in figure 1 . injured endothelium results in impairment in the synthesis and the release of the potent vasodilator nitric oxide and also promotes the accumulation of reactive oxygen species and other inflammatory factors which mediate the development of atherosclerosis , thrombosis , and vascular occlusion . this inflammatory process is a prominent feature in the pathogenesis of both hypertension and atherosclerosis . some mechanisms such as the rennin - angiotensin - aldosterone system ( raas ) and the sympathetic nervous system that maintain hypertension are also those that promote atherosclerosis . angiotensin ii increases bp and facilitates progression of atherosclerosis through vasoconstrictive and vascular remodeling effects . this observation led to the idea that some antihypertensive agents such as angiotensin - converting enzyme ( ace ) inhibitors may have beneficial effects on atherosclerosis and chd in addition to their bp lowering effect . hypertension by itself can cause myocardial ischemia in the absence of chd . increased afterload due to hypertension can result in significant left ventricular hypertrophy ( lvh ) , which may impair ventricular relaxation and compromise coronary blood flow during diastole . although genetic factors have been associated with lvh , chronic uncontrolled hypertension appears to be the major cause [ 13 , 14 ] . research has shown that lvh diminishes coronary flow reserve and independently predicts future chd , hf , stroke , and sudden cardiac death . both jnc 7 and 2007 aha guideline stressed the importance of antihypertensive therapy in the high - risk population , including chd [ 1 , 9 ] . in jnc 7 , target bp was defined for general population and patients with diabetes , hf , and renal disease , but not for those with chd . however , aha guideline clarified this issue and recommended the same target bp of 130/80 mm hg as for other high - risk population with caution in lowering the dbp below 60 mmhg which may impair coronary perfusion . the goals of treating hypertension in patients with chd are to lower bp , reduce ischemia , and prevent cardiovascular events and death . to achieve these goals , both nonpharmacological interventions and pharmacological therapy exercise improves cardiac function , reduces bp and cardiac afterload by a variety of mechanisms , including reduced arterial stiffness . research has shown that physical activity predicts the likelihood of cvs disease beyond that explained by the commonly measured cardiometabolic risk factors . although the mechanism is not entirely clear , evidence indicates that exercise improves coronary artery flow reserves in chd patients and pathophysiological mechanisms that are potentially important in generating chd have been linked to physical activity . studies have also shown that various lifestyle behaviors , including unhealthy diet , physical inactivity , and smoking , promote the development and clinical manifestations of chd . therefore , lifestyle changes and adoption of healthful behaviors are equally important in the management of hypertension and chd . special attention should be given to weight loss , diet control , salt intake , alcohol consumption , smoking , and stress management . pharmacological treatment is inevitable in high - risk populations such as those with chd , although lifestyle modifications alone may suffice in the general population with prehypertension . the recommended target bp for individuals with chd or chd equivalents : diabetes mellitus , chronic renal disease , peripheral arterial disease , carotid artery disease , and abdominal aortic aneurysm is < 130/80 mm hg . although several antihypertensive agents exist , it is not completely clear whether all antihypertensive agents are equally effective in preventing or decreasing progression of chd . here the treatment of hypertension in chd patients should begin with -blockers as first - line therapy , unless contraindicated [ 2225 ] . relative contraindications to their use include hypotension , severe bronchospastic lung disease , decompensated hf , sinus or atrioventricular node dysfunction , and severe peripheral vascular disease . also , diabetic patients with significant history of hypoglycemic episodes should use -blockers with great caution because of the risk of masking symptoms of hypoglycemia . these agents reduce myocardial oxygen consumption and heart rate and enhance coronary flow by increasing diastolic filling period . among patients with both acute myocardial infarction ( mi ) and hypertension , -blockers have been shown to limit infarct size , improve survival , and decrease the risk of recurrent mi and the incidence of sudden cardiac death , which is secondary to fatal arrhythmias [ 2628 ] . while metoprolol , carvedilol , and bisoprolol were shown to improve outcomes in hf patients , atenolol - based therapy was found to be inferior to amlodipine - based therapy in reducing cvs events in the anglo - scandinavian cardiac outcomes trial ( ascot ) . similarly , a substudy of ascot , the conduit artery function evaluation ( caf ) , showed that atenolol was less effective in reducing systolic bp and cardiac afterload than amlodipine , which perhaps could be explained by the observation of increased arterial stiffness and aortic wave reflections in patients using beta - blockers . hence , in the absence of mi , chd , or hf , the use of -blockers as first - line therapy for hypertension is controversial and not supported . long - acting dihydropyridines calcium channel blockers ( ccbs ) , amlodipine , and nifedipine can be added to the basic regimen if bp remains elevated or angina continues while on -blocker therapy . the nondihydropyridine agents , diltiazem and verapamil , can also be substituted for -blocker when contraindications exist or side effects develop . although nondihydropyridine ccbs can be used as antianginal in combination with a -blocker , there is associated risk of severe bradycardia or atrioventricular block . therefore , if a ccb is needed in addition to -blocker to control angina or bp , it should be a long - acting dihydropyridine ccb . these agents decrease bp by causing vasodilation and decreasing peripheral resistance and wall tension , thus reducing myocardial o2 demand . the controlled - onset verapamil in cardiovascular endpoint ( convince ) trial , the nordic diltiazem ( nordil ) study , and the international verapamil sr / trandolapril ( invest ) study showed that outcomes with ccbs - based therapy were not different from those of -blockers - based therapy [ 3335 ] . based on these studies , ccbs appear to be good substitutes for -blockers in the treatment of angina in hypertensive patients ; however , they are not recommended for secondary prevention because of their inability to prevent ventricular dilatation and hf [ 3640 ] . hence , nondihydropyridine agents should not be used in patients with systolic hf and short - acting dihydropyridine ccbs should be avoided in patients with acute mi , pulmonary edema , or lv dysfunction [ 24 , 42 , 43 ] . the role of ccbs in the prevention of cvs events among patients with chd remains unclear , and several studies that evaluated cvs outcome with the use of ccbs have yielded mixed results [ 35 , 3740 , 44 , 45 ] . nitrates have not been shown to be of significant use in hypertension treatment ; however , they are indicated for acute relief of angina or treatment of chronic angina which can not be controlled with -blockers and ccbs . the reports of two large trials comparing nitrates with placebo showed no difference in mortality with the use of nitrates [ 46 , 47 ] . hence , nitrates are not recommended to reduce cardiac events but only to relieve angina , control bp , and manage pulmonary congestion . however , individuals taking nitrates should be advised not to use phosphodiesterase inhibitors such as sildenafil , as the combination of both may cause severe hypotension . two major trials , the european trial on reduction of cardiac events with perindopril in stable coronary artery disease ( europa ) and heart outcome prevention evaluation ( hope ) study , showed the cardioprotective effect of ace inhibitor in hypertensive chd patients [ 4851 ] . in the europa study , 12,218 patients were randomized to treatment with an ace inhibitor ( perindopril ) or placebo . individuals in the perindopril group had significantly less mi , cvs death , or cardiac arrest . the hope study involved 9,297 patients with cvs risk factors , who were randomized to ramipril or placebo . ramipril therapy was associated with small ( 3/2 mm hg ) reduction in bp but significant reduction in cvs death , stroke , and mi [ 49 , 50 ] . these cardioprotective effects were initially thought to be independent of bp control , until a subgroup analysis of the hope trial revealed a significant reduction in 24-hour ambulatory bp with ramipril that was not found in the main trial that measured only office bp . in another trial , the prevention of events with angiotensin converting enzyme inhibition ( peace ) , involving stable chd patients with normal or slightly reduced ejection fraction , there was no difference between trandolapril therapy and placebo in the incidence of mi or coronary revascularization , despite 4.4/3.6 mm hg reduction in bp . the findings of this study raised question about the usefulness of ace inhibitors in low - risk chd patients with normal lv systolic function . thus , ace inhibitors are indicated for all hypertensive patients with acute mi who have no contraindications , especially if there is associated depressed lv systolic function ( lvef < 40% ) [ 53 , 54 ] . in individuals who are ace inhibitor intolerant or allergic , angiotensin receptors blockers ( arbs ) have been shown to be an effective alternative in the treatment of hypertension , chd , and hf . emerging data appear to support the use of arbs in mi . in the valiant study , the arb , valsartan was as effective as captopril in patients at high risk of cvs events after mi [ 55 , 56 ] . among 15,245 hypertensive patients that were enrolled in the valsartan antihypertensive long - term use evaluation ( value ) trial , the arb , valsartan , and ccb , amlodipine had similar primary protection against cvs events . hence , arb appears to be a good substitute in those individuals in which acei is contraindicated . the allhat trial clearly showed the benefit of thiazide diuretic in the treatment of hypertension [ 3739 ] , although there are concerns about the contribution of the metabolic effects of thiazide to chd risk . the effectiveness of thiazide in controlling bp and preventing cvs events has been demonstrated in several studies [ 5860 ] , but their use in the setting of acute mi is not encouraged and if at all required , should be done with caution . while there is an ongoing debate over whether the clinical benefits observed with thiazide - type diuretic are drug specific , it is not unreasonable to assume that there is a class effect , given the high degree of homogeneity in the mechanism of action of this group of antihypertensive agents . the control of bp is more important than the choice of antihypertensive agent in the prevention chd and other complications of hypertension [ 61 , 62 ] . research has shown that effective combination of antihypertensive agents is usually required to achieve and sustain long - term bp control . therefore , the most important strategy for achieving target bp level is by using combination therapy most especially in individuals with stage 2 hypertension . other adjunctive therapies such as antiplatelet therapy and the use of statins are also encouraged for lowering atherosclerotic burden in chd patients . nonpharmacological therapy such as regular exercise , smoking cessation , healthy diet , and healthful psychosocial functioning should be emphasized in all patients , even when antihypertensive agents are being used . the target bp in hypertensive patients with chd is < 130/80 mm hg with caution in lowering the dbp below 60 mm hg . to achieve this target , effective combination antihypertensive drug therapy is usually required to achieve and sustain long - term bp control . treatment regimen should include -blocker , ace inhibitor , or arb , most especially if there is lv systolic dysfunction and/or diabetes mellitus , and possibly a thiazide diuretic . ccbs can be used as alternative to -blocker or added to the basic regimen , and nitrates are useful for relieve of ischemic pain . the overall goal of therapy is to reduce morbidity and mortality associated with both hypertension and chd . as more data from hypertension trials are made available , we anticipate changes in the recommendations of the forthcoming jnc 8 . Output:	evidence suggests that coronary heart disease ( chd ) is the most common outcome of hypertension . hypertension accelerates the development of atherosclerosis , and sustained elevation of blood pressure ( bp ) can destabilize vascular lesions and precipitate acute coronary events . hypertension can cause myocardial ischemia in the absence of chd . these cardiovascular risks attributed to hypertension can be reduced by optimal bp control . although several antihypertensive agents exist , the choice of agent and the appropriate target bp for patients with chd remain controversial . in this succinct paper , we examine the evidence and the mechanisms for the linkage between hypertension and chd and we discuss the treatment options and the goals of therapy that are consistent with the report of the seventh joint national committee on the prevention , detection , evaluation , and treatment of high blood pressure ( jnc 7 ) and american heart association scientific statement . we anticipate changes in the recommendations of the forthcoming jnc 8 .
PubmedSumm118881	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: judgments of the temporal order or simultaneity of two stimuli are collected in studies of prior entry , multisensory integration , or causality perception ( schneider and bavelier , 2003 ; stetson et al . , 2006 ; spence and parise , 2010 ; vroomen and keetels , 2010 ; yates and nicholls , 2011 ) and , more generally , in research on perception of temporal order ( sternberg and knoll , 1973 ; occelli et al . , 2011 ) . the two stimuli that are involved may pertain to different sensory modalities but , without loss of generality , we will assume the audiovisual case in the following description . in these experiments , visual and auditory stimuli are presented with a range of auditory delays ( or stimulus onset asynchrony , soa ) , defined as the difference between the onset of the auditory stimulus and that of the visual stimulus . in the ternary version of the simultaneity judgment task ( sj3 task ; ulrich , 1987 ) , the observer must judge whether the auditory stimulus was presented before , after , or simultaneously with the visual stimulus , yielding audio - first ( af ) , video - first ( vf ) , or models of timing judgments fall within the class of independent - channels models described by sternberg and knoll ( 1973 ) , in which signals from the two stimuli reach a central mechanism with randomly distributed arrival latencies . at the central mechanism , the judgment arises on application of a decision rule to the arrival - time difference between the signals . sternberg and knoll derived general properties of independent - channels models without making assumptions about the distribution of arrival latencies or about the form of the decision rule . with explicit assumptions about these components , independent - channels models yield expressions for the psychometric functions af , s , and vf , respectively describing how the probabilities of af , s , and vf judgments vary with auditory delay . sternberg and knoll also showed that the attention - switching models of kristofferson and allan ( 1973 ) can be cast in terms of independent - channels models and , thus , they do not represent an essentially different type of models as regards the issues addressed in this paper . a theoretically important feature of independent - channels models of perception of temporal order is that they entail a representation of the processes governing observed performance at timing judgment tasks . model parameters are thus straightforwardly interpretable as reflecting characteristics of the distributions of arrival latencies ( determined by sensory transmission and perceptual processing ) , and they also characterize the observer as a decision maker whose judgments rely on sensory information , subject to limitations imposed by the temporal resolution with which observers can tell small differences in arrival latency . these models are thus useful in studies of prior entry or temporal recalibration because parameter estimates directly indicate how experimental manipulations affect either the distributions of arrival latencies or the operating temporal resolution of the observer . however , empirical tests of the models revealed their inadequacy because data failed to satisfy certain formal properties that should manifest in sj3 tasks . for instance , allan ( 1975 ) showed that independent - channels models imply that vf should differ from 1 af only by horizontal translation ( a property called parallelism ) , but her data did not bear out this prediction . ulrich ( 1987 ) showed that these models ( as well as attention - switching models ) also imply that vf should be a strictly increasing function whereas af should be a strictly decreasing function ( a property called monotonicity ) , he derived further properties of the models , and he also reported data violating them . alternative models were proposed by allan and by ulrich and yet another model was later proposed by jaskowski ( 1991 ) , but these alternative models are not without problems either . for instance , allan s model is an amended attention - switching model that includes guessing mechanisms and predicts four - limbed linear psychometric functions always including a zero - slope limb ; the model can account for lack of parallelism but not for lack of monotonicity , but piecewise linear psychometric functions including a flat portion for af and vf data have never been reported . ulrich only sketched an amended attention - switching model that he regarded as very promising but , to the authors knowledge , development and test of this model was never published . finally , jaskowski s model is an amended independent - channels model with dual streams on the assumption that judgments of successiveness and judgments of temporal order arise from independent processing paths , an assumption whose validity had been empirically disproved by allan ( 1975 ) . perhaps because of these shortcomings , none of these alternative models has been subsequently used to fit sj3 data ( for the single exception that we are aware of , see jaskowski , 1993 ) . by putting aside independent - channels models and their variants for the analysis of timing judgment data , benefits of the interpretability of their parameters are lost . but data must nevertheless be analyzed somehow and current practice consists of fitting arbitrary functions of adequate shape to the data . thus , survival gaussians are typically fitted to accommodate the decreasing trend of af data ( or equivalent data when other sensory modalities are involved ) , cumulative logistic or gaussian functions are used to fit the increasing trend of vf data ( or their equivalent for other sensory modalities ) , and gaussians or piecewise cumulative - survival gaussians are fitted to inverted - u shaped s data ( shore et al . , 2002 ; stone et al . , 2001 ; spence et al . , 2003 ; harrar and harris , 2008 ; van eijk et al . , 2008 , 2010 ; , 2008 ; fujisaki and nishida , 2009 ; yates and nicholls , 2009 , 2011 ; nicholls et al . , although separate functions fitted in this way can capture lack of parallelism of af and vf data , the fitted functions are monotonic and can not accommodate lack of monotonicity in the data . also , and for lack of a theoretical framework within which these arbitrary functions are derived , their parameters only describe the data themselves with no links to interpretable parameters that might indicate the characteristics of underlying processes . one aspect that has never been considered theoretically in any depth is that observers occasionally have lapses of attention ( yielding pure guesses as responses ) or make errors upon pressing the response keys ( sometimes yielding unexpected responses ) . besides the observers spontaneous reports of these events at the end of the experimental session , inspection of raw data typically shows evidence of them , namely , unexpected af responses at long positive auditory delays ( where vf responses should always occur ) and unexpected vf responses at long negative auditory delays ( where af responses should always occur ) . the arbitrary functions referred to above are also typically fitted without allowance for asymptote parameters that account for these events ( for rare exceptions , see spence et al . allan s and ulrich s analyses of the properties of independent - channels models did not consider these events either . this contrasts with the tradition in other fields ( e.g. , visual psychophysics ) , where the importance of including lapse or finger - error parameters in psychometric functions is acknowledged ( see swanson and birch , 1992 ; wichmann and hill , 2001 ) . in this paper we explore whether an extension of independent - channels models that considers these factors can account for data showing lack of monotonicity and lack of parallelism , which would generally be taken as ruling out such models entirely . consideration of parameters to represent these factors in the ternary sj3 task is slightly more complex than in the binary tasks involved in visual psychophysics . thus , we first present an amended independent - channels model that includes parameters to represent response errors in a realistic manner and we show that parallelism and monotonicity are no longer properties of the model when response errors are considered . subsequently , we show that the model fits sj3 data adequately and , hence , that empirically observed deviations from these properties can be explained as a consequence of these events . the importance of this result lies in that independent - channels models can be reinstated and , thus , temporal order judgment data can be analyzed in terms of the interpretable parameters of these models . thus , data can be used to make direct inferences about the underlying processes ( e.g. , distributions of arrival latencies across experimental conditions in studies of prior entry ) instead of merely used to obtain quantitative indices that describe empirical performance through arbitrary functions that lack theoretical underpinnings . our starting point is an independent - channels model similar to a perceptual latency model with a threshold decision process ( allan , 1975 ) or to a triggered - moment model ( schneider and bavelier , 2003 ) , with some modifications . the arrival latencies tv and ta of visual and auditory signals are random variables with densities gv and ga , respectively . in contrast to the gaussian assumption in the models just mentioned , we will assume shifted exponential distributions given by where ti ( in ms ) is the actual onset of the corresponding signal , i ( in ms ) is the rate parameter of the distribution ( indicating how fast probability density decreases as t increases ) , and i ( in ms ) is a further processing delay . exponential distributions are commonly assumed to describe arrival latencies and peripheral processing times ( heath , 1984 ; colonius and diederich , 2011 ; diederich and colonius , 2011 ) , whose mean is thus 1/i + i and whose sd is 1/i . without loss of generality , we set the origin of time at the onset of the visual stimulus so that tv = 0 and , thus , t ta is the auditory delay manipulated experimentally , where t < 0 ( t > figure 1a shows sample distributions for a = 1/60 , v = 1/30 , a = 20 , and v = 40 when the auditory delay is t = 50 . on a given trial , arrival latencies are realizations of these distributions and the observer s judgment arises from a decision rule applied to the arrival - time difference d = ta tv , which has a bilateral exponential distribution given by model of timing judgments . ( a ) exponential distributions for the arrival latency of a visual stimulus ( red curve ) presented at time 0 and an auditory stimulus ( blue curve ) presented at time t = 50 ms . ( b ) bilateral exponential distribution of arrival - time differences and boundaries on the decision space ( vertical lines , at d = with = 100 ) , determining the probability of each type of judgment . error - free psychometric functions for each type of response as a function of auditory delay . circles denote the probabilities indicated in ( b ) for t = 50 ms . ( d ) psychometric functions when response errors occur as described in the text . where = a v . figure 1b shows the distribution of arrival - time differences for the case in figure 1a . a resolution parameter which was referred to as threshold by sternberg and knoll ( 1973 ) , allan ( 1975 ) , and ulrich ( 1987 ) and as moment duration by schneider and bavelier ( 2003 ) limits discriminability so that an af judgment occurs when d is sufficiently large and negative ( d < ) , a vf judgment occurs when d is sufficiently large and positive ( d > ) , and an s judgment occurs when the arrival - time difference is below the resolution limit ( d ) . for the example in figure 1b , where = 100 , the probability of af , s , and vf judgments are , respectively , 0.0044 , 0.7880 , and 0.2076 ( as indicated in figure 1b ; see also the circles on the curves of figure 1c ) . these probabilities change with auditory delay t and figure 1c shows complete psychometric functions . to obtain them , first note that the cumulative distribution for d is where f is given byeq . clearly , vf and af are both monotonic and parallelism holds because vf(t ) = 1 af(t + 2 ) , that is , the blue curve in figure 1c differs from an upside - down reversal of the red curve only by a lateral shift . equations 4a4c give the probabilities of the unobservable af , s , and vf judgments as a function of auditory delay , but the probabilities of observed af , s , and vf responses may differ from them . for instance , errors in pressing the response keys make the observer s response differ from the judgment that was made . in addition , blinks or lapses of attention preclude judgments at all and force the observer to guess a response that may not match the judgment that would have been made in the absence of a lapse . we will refer to these misreports as response errors and lapses , respectively , and we will first describe how to incorporate the former into the model . let af , s , and vf be the probabilities ( or error rates ) that the observer misreports af , s , and vf judgments , respectively , as a result of an error in pressing the response keys . these errors may actually differ across the judgments that were made , if only because the layout of the response interface may make the observers more likely to misreport one of the judgments and , in such cases , also more likely to misreport it in a particular form . since misreporting any given judgment can take two forms ( i.e. , there are two possible intruding responses ) , let a - b be the conditional probability of misreporting an a judgment as a b response so that a - c = 1 a - b is the conditional probability of misreporting an a judgment as a c response . only three conditional probabilities are free parameters , say , s - af , vf - af , and af - s , because s - vf = 1 s - af , vf - s = 1 vf - af , and af - vf = 1 af - s . the model incorporating response errors thus becomes where af , s , and vf on the right - hand sides are given by eqs 4a4c . figure 1d shows the resultant psychometric functions for an observer with a relatively high error rate whereby vf judgments are misreported as af responses ( vf = 0.18 and vf - af = 1 ) , a weaker error rate whereby af judgments are misreported as vf responses ( af = 0.12 and af - s = 0 ) , and no misreports of s judgments ( s = 0 ) . note that the blue and red curves in figure 1d are non - monotonic and do not satisfy parallelism ( after upside - down reversal ) . note also that an absence of errors ( i.e. , af = s = vf = 0 ) renders the model in eqs 4a4c , in which responses faithfully indicate judgments . equations 4a4c give the probability of ( unobservable ) judgments , whereas eqs 5a5c give the probabilities of observed responses . thus , observed responses potentially reflect mixtures of authentic judgments and intrusions due to errors upon reporting judgments of other types . we will refer to the weights of the intruding responses in these mixtures as intrusion parameters . for the example in figure 1d , eqs 5a5c become so that s=s for lack of intrusions from af and vf judgments and also for lack of intrusion of s judgments into af and vf responses . in contrast , af misses 12% of the authentic af judgments ( which intrude into vf responses ) and vf * misses 18% of the authentic vf judgments ( which intrude into af responses ) . our next step to model development considers lapses of attention . these lapses ( or blinks , yawns , sneezes , ) obviously occur randomly across trials and independently of the auditory delay at the trial and also independently of the judgment that would have been made in the absence of a lapse . there is a ( conceivably small ) probability that a lapse occurs on some trial and , in such case , an observer can only arbitrarily give af , s , or vf responses perhaps with some bias . let af , s , and vf = 1 af s be the probabilities of these responses in case of a lapse , where af = s = vf = 1/3 for an unbiased observer ( although unbiased guessing behavior can not be generally assumed in advance ) . the model incorporating only lapses and the ensuing ( potentially biased ) guesses thus becomes the effect of lapses on the shape of observable psychometric functions can be described without graphical illustration : compared to the psychometric functions in figure 1c , multiplication by 1 shrinks the range of the functions ( i.e. , shifts the upper asymptotes of af and vf down and also scales s down , without affecting the lower asymptotes of any of them ) whereas the additive term pushes the functions upwards by a small amount , thus shifting the lower asymptotes upwards . now , combining the effects of lapses and response errors into an integrated model is as simple as replacing the unmarked psychometric functions on the right - hand sides of eqs 7a7c with the right - hand sides of eqs 5a5c , yielding the effect of lapses in this integrated model is again analogous to that described above , except that the shrunken range and vertical shift occur for the psychometric functions in figure 1d instead of those in figure 1c . there are three reasons why we will not consider this integrated model , all of which pertain to the limited utility of modeling lapses . the first one is that the model for lapses in eqs 7a7c violates parallelism but not monotonicity : all that is implied when only lapses occur is vertical shrinkage and vertical shift of the psychometric functions and , thus , lapses can not possibly account for the non - monotonicity observed in some data sets . second , the integrated model in eqs 8a8c is unidentifiable , as lapses and response errors both affect the asymptotes of the psychometric functions in an inextricable way for lack of independent evidence as to how much of the effect found in empirical data is caused by lapses and how much is caused by response errors . finally , many experiments are designed so as to eliminate the influence of lapses by enabling an additional response key for observers to abort the trial if they missed the stimuli and could not make a judgment . this key is usually programmed so that the trial is placed back in the stack of pending trials for administration at a later time ( generally not immediately afterward ) , and observers are instructed to refrain from using this key if they only were uncertain and wanted to have a second chance . if the commendable precaution to enable such abort key is taken , lapses do not need to be modeled at all . our decision to use only the model with response errors should not be misconstrued for a denial of the existence of lapses . in the context of our goals in this paper , the potential effects of lapses are absorbed by the error parameters in the model that we will use , and the only consequence is that the estimated values for these parameters can not be literally interpreted as representing only the probabilities of response errors . this is not a crucial problem , because the relevant parameters in research on prior entry or perception of temporal order are only a , v , , and ; parameters describing errors or lapses are rarely of any theoretical interest and they are included in the model only to improve the accuracy with which the relevant parameters are estimated . ( 2008 ) from an audiovisual sj3 task carried out by 11 observers . only results for data from their flash click stimulus will be presented here , as data from the other stimulus yielded similar outcomes . the visual component of the stimulus was a white disk flashed for 12 ms against a dark background and the auditory component was a 12-ms white - noise burst . auditory delays ranged from 350 to 350 ms in steps of 50 ms , and 60 trials were administered at each auditory delay . model parameters for each observer were sought by maximizing the likelihood equation where r is the set of empirical responses , = ( a , v , , , af , s , vf , s - af , vf - af , af - s ) is the vector of free parameters , { t1 , t2 , , tn } is the set of n = 15 auditory delays at which responses were collected , and ai , si , and vi are the observed counts of af , s , and vf responses at ti . equation 9 was maximized using nag subroutine e04jyf ( numerical algorithms group , 1999 ) , which implements a quasi - newton algorithm for constrained optimization . the parameter space spanned the ranges [ 1/200 , 1 ] for a and v , the range [ 150 , 150 ] for , the range [ 0 , 300 ] for , the range [ 0 , 0.8 ] for af , s , and vf , and the range [ 0 , 1 ] for af - s , s - af , and vf - af . two or three initial values were defined for each parameter , which were evenly spaced within the search space for that parameter . initial values for each parameter were factorially combined to yield 3 2 starting points in the 10-dimensional parameter space and the maximization routine ran for each of these starting points , yielding in each case a vector of estimates and a divergence index . on completion , we took the vector of estimates for which divergence was lowest and the likelihood - ratio statistic g was computed as a measure of goodness - of - fit because this statistic is the one that maximum - likelihood estimates minimize ( collett , 2003 , pp . 8788 ) . thus , we estimated parameters and measured the goodness of the fit using the same currency ( wichmann and hill , 2001 ) . the asymptotic distribution of all goodness - of - fit statistics is known to yield inaccurate significance levels when expected frequencies are small ( garca - prez , 1994 ; garca - prez and nez - antn , 2001 , 2004 ) and this is a common encounter when fitting psychometric functions . for this reason , significance levels were obtained through parametric bootstrap by simulating 5000 data sets using the estimated parameters for each observer and the same number of auditory delays and trials per delay as in the actual experiment . figure 2 shows empirical data and fitted functions for each observer , and also shows a summary panel for average data and average fitted curves for all observers ( which we include only because this is the format in which alternative fitted curves were reported by van eijk et al . , table 1 lists parameter estimates as well as the value and p - value of the g statistic for each observer . perhaps the most salient aspect of figure 2 is that model curves follow the path of the data accurately , accommodating systematic deviations from monotonicity in af and vf data . also , s data ( black circles ) show symmetric or asymmetric patterns that are well described by the model functions ( black curves ) . despite the visual quality of the fit , a goodness - of - fit test rejected the model for three observers ( stars in table 1 ) but these rejections seem spurious , as discussed next . the data vary smoothly up to intermediate positive auditory delays , and the model curves follow the path of the data very accurately . yet , at the four longest positive auditory delays s data ( black circles ) and vf data ( blue circles ) appear somewhat noisy , unlike af data ( red circles ) at the same auditory delays . thus , it seems that this observer was occasionally misreporting vf judgments as s responses at long positive auditory delays . it is hard to imagine how an alternative model might produce curves that accommodate the smoothly varying data points on the left and center of the panel and then suddenly wind strangely to also accommodate the stray vf and s data points on the far right . it is even harder to agree to model rejection for observers 4 and 9 ( for whom the p - values are also only marginally significant ; see table 1 ) , since model curves follow the path of the data accurately across the panel except for occasional data points that deviate haphazardly from the path of the rest of the data . in all cases , the fitted model does not deviate systematically from the data for any observer but the stray location of some data points sometimes causes statistical rejection . an analysis of residuals identified the data points that caused rejection of the model for each observer , and these points are indicated by arrows in figure 2 . note that , for observer 3 , the only two misfitting data points involving af and vf responses ( indicated with red and blue arrows ) imply very small observed frequencies and expected frequencies that are even smaller , a well - known cause of improper model rejections ( garca - prez , 1994 ; garca - prez and nez - antn , 2001 , 2004 ) . estimated model parameters . the columns labeled g and p - value respectively give the value and bootstrap significance level of the likelihood - ratio statistic ; stars indicate rejection at the 5% significance level . data and fitted curves in the flash click experiment of van eijk et al . the numeral in each panel denotes the observer ; the panel at the bottom right shows summary results as averages of data and averages of the fitted functions across the 11 observers . arrows in the panels for observers 3 , 4 , and 9 indicate the data points responsible for the misfit according to a residual analysis . we do not report sample - wise goodness - of - fit analyses because there is no reason that the model should hold for a given sample as a whole ( or just for 95% of the samples when the type - i error rate is 0.05 ) but also because analyzing data aggregated across observers poses serious problems ( estes , 1956 ; estes and maddox , 2005 ) . a subject - by - subject analysis of fit seems more reasonable and is the only means for identifying problematic assumptions in a model and potential replacements for them . although figure 2 shows that the model fits the data adequately , we checked for parallelism of vf data ( blue symbols ) and inverted af data ( red symbols ) for each observer , as follows . first , the locations tvf - pss and taf - pss of the 50% point on af * and vf * were determined . then , we plotted 1-af(t+taf - pss ) and vf(t+tvf - pss ) , thus shifting them so that their 50% points coincide . finally , we shifted the data analogously and also plotted them ( after upside - down reversal of af data ) . the results are shown in figure 3 along with a summary panel for data and curves averaged across observers . the curves only show some deviations from parallelism for observers with relatively high error rates ( observers 2 , 3 , 5 , 7 , and 10 ; see table 1 ) , and these deviations mostly affect the outer ends of each curve , where non - monotonicity also occurs ( see figure 2 ) . it is interesting to note that the data for which allan ( 1975 ) and ulrich ( 1987 ) reported a failure of parallelism also showed non - monotonic patterns at the outer ends , as is expected from intrusions from vf and af judgments into af and vf responses . this characteristic is more apparent in the plots that jaskowski ( 1991 ) presented for the same data . test of parallelism . in comparison to figure 2 , af and vf data and curves are merely shifted horizontally ( and inverted upside - down in the case of af data ) . overfitting applies to models that have an unnecessarily large number of parameters and , thus , fit data by sheer volume of parameters . all the parameters in our model have empirical referents and , thus , their inclusion is justifiable . each parameter produces a distinctive and identifiable effect on the shape of the psychometric function , and these effects are not confounded ( when lapses and the ensuing guesses are eliminated by design ) . and , more important , the data to which the model was fitted here show clear signs of these effects , which produce the non - monotonicity and lack of parallelism that conventional models can not account for . when considering the risk of overfitting , a comparison with the conventional approach that separately fits arbitrary functions to af , s , and vf data is enlightening . in particular , on analyzing this same data set , van eijk et al . ( 2008 ) fitted a four - parameter function to af data , an independent four - parameter function to vf data , and still two other independent three - parameter functions to s data ( one of them for the ascending part and the other for the descending part ) . this yields a total of 14 parameters to describe the same data . without the simplifications used by van eijk et al . not only the number of parameters is larger than that implied in our model , the functions fitted in this way can not produce non - monotonic shapes for af or vf data and the estimated parameters are uninterpretable in terms of underlying processes : they only indicate the slope , location , and asymptotes of the fitted functions . nevertheless , there is still the issue of whether some of the parameters of our model could be disposed of ( particularly some of those representing response errors ) , or whether the simpler model with lapses would suffice to account for the data without response errors . the latter issue can be easily dispatched , as we showed above that a model including only lapses can not produce non - monotonic psychometric functions for af and vf data . since the data actually show these characteristics , the model with only lapses ( eqs 7a7c ) is disproved . to show that overfitting does not affect the model including response errors , we fitted simpler versions of it to the data , as described next . in the simplest version , response errors are assumed to not occur at all , which implies making af = s = vf = 0 ( wiping out s - af , vf - af , and af - s along the way ; see eqs 5a5c ) and leaving a model with only four free parameters ( a , v , , and ) . the results are shown in figure 4 , which reveals that forcing model curves to have their asymptotes at 0 or 1 ( as applicable ) prevent them from accommodating the data , and the fit is particularly bad for observers whose data show clear signs of non - monotonicity or lack of parallelism . the g statistic rejected the model for all observers ( the largest p - value across observers was 0.002 ) , a result that raises no concerns of potentially improper rejections given the obvious mismatch between the path described by the data and the path described by the curves in figure 4 . results of fitting a simpler version of the model in which no response errors are assumed to occur . , all response errors were assumed to occur with the same probability ( which implies making af = s = vf = ) and errors were further assumed to take all possible forms with the same probability ( which implies making s - af = vf - af = af - s = 1/2 ) . this renders a model with five parameters ( a , v , , , and ) for which figure 5 shows the results . again , the assumption that all response errors are equally likely prevents the model from fitting data that show clear signs to the contrary : this assumption forces the lower asymptote of all curves to be at the same height , and the upper asymptotes of curves for af and vf data to also be at the same height , but the data say otherwise . this model was rejected for all observers except 2 , 6 , and 11 , but it does not seem to do justice to the data for observer 2 ( see data and curves in the bottom part of the panel for this observer in figure 5 ) . results of fitting a version of the model in which all types of response error are assumed to occur with the same probability and where the two types of misreported responses in case of error are assumed to occur with the same probability . we also tried out other simplifications , with analogous outcomes . although some models fitted the data for some observers , accounting for the diversity of patterns of non - monotonicity and lack of parallelism across observers was impossible without allowance for all parameters . but this allowance does not imply that all parameters were actually useful to fit the data for all observers . indeed , fitting the full model eliminates unnecessary error parameters by estimating them at or near zero . consider the data for observer 3 in figure 2 and note in table 1 that the estimated values of af and s are nearly zero , which makes the estimated values of parameters s - af and af - s meaningless and immaterial . at the same time , the estimated value of vf is 0.147 with an estimated vf - af of 0 ( or , equivalently , a derived value for vf - s of 1 , which are both meaningful because their companion error parameter vf is not null ) . this matches what the data for observer 3 suggest : only vf judgments seem to be occasionally misreported and always in the form of s responses . a similar analysis for observer 10 reveals the same match between features of the data and interpretation of parameter estimates , with the implicit elimination of unnecessary error parameters and their companion s . four of the ten free parameters in the model ( a , v , , and ) govern judgments and six ( af , s , vf , s - af , vf - af , and af - s ) pertain to response errors . this may raise concerns of theoretical identifiability , that is , whether different sets of parameter values may produce the same psychometric functions af * , and s*. since the problem can not be addressed analytically , we took the approach of determining the extent to which the generating parameters were recovered from data sets essentially implying an infinite number of observations ( because sampling error is not of concern here ) . one - thousand data sets were produced from random combinations of parameters with uniform distributions on [ 1/80 , 1/20 ] for a and v ( independently ) , on [ 80 , 80 ] for , on [ 20 , 150 ] for , on [ 0 , 0.1 ] for af , s , and vf ( independently ) , and on [ 0 , 1 ] for af - s , s - af , and vf - af ( independently ) . the particular parameters that would produce each data set were inserted into eqs 5a5c and the resultant probabilities at auditory delays ranging from 350 to 350 ms in steps of 50 ms were transformed into ( rounded off ) expected numbers of af , s , and vf responses across 10,000 putative trials per auditory delay . the model was subsequently fitted to each data set and parameter estimates were compared with the generating parameters in search for evidence of non - identifiability . the results are shown in figure 6 in the form of scatter plots of estimated against true parameter values . as is clear , all parameters are recovered with no evidence of non - identifiability . the minor misestimation problems affecting conditional probabilities af - s , s - af , and vf - af ( third row in figure 4 ) are only a result of the fact that evidence on their actual values is limited or null when af , s , and vf are very small . the bottom row of figure 6 shows that this misestimation is not a problem when intrusion parameters are considered . theoretical parameter identification . each panel shows a scatter plot of estimated value against true value for the parameter indicated at the top - left corner , including the ten parameters of the model ( first three rows ) and the derived intrusion parameters ( bottom row ) . non - identifiability would show as data points falling along lines or curves other than the diagonal identity line in two or more panels within the first three rows . a related issue is that of practical identifiability , that is , the extent to which model parameters can be recovered accurately from a finite number of observations affected by sampling error . when theoretical identifiability holds , as just documented , lack of practical identifiability speaks more of the scarcity of data than it speaks of the model itself . we looked into this issue under the same conditions discussed in the preceding paragraph ( i.e. , n = 15 auditory delays and the same ranges of generating parameters ) , but now using 1000 sets of simulated counts ( instead of expected counts ) for numbers of trials ranging from 50 to 400 per auditory delay . the accuracy with which parameters were identified was measured through the concordance coefficient ( lin , 1989 ) . the results are shown in figure 7 , which indicates how the concordance coefficient varies with number of trials per auditory delay . the parameters describing perception of temporal order ( a , v , , and ; first panel ) , the error parameters af and vf ( second panel ) , and the conditional probabilities af - s and vf - af ( third panel ) can be sufficiently accurately recovered with 100 trials per auditory delay . yet , s and s - af are harder to recover , a result of the fact that misreports of s judgments ( which would occur at short auditory delays ) are harder to identify than misreports of af or vf judgments ( which would occur at long positive and negative auditory delays ) . each panel shows how recovery of the 10 parameters of the model ( first three panels ) and the derived intrusion parameters ( fourth panel ) varies with the number of observations collected at each of 15 auditory delays ranging from 350 to 350 ms in steps of 50 ms . an asymptotic 0.05-size chi - square test yielded empirical rejection rates of 4.3 , 4.1 , 5.4 , and 5.5% as the number of observations per auditory delay increased from 50 to 400 ; an analogous asymptotic 0.05-size likelihood - ratio test yielded inaccurate empirical rejection rates of 8.1 , 8.0 , 7.3 , and 8.3% . in sum , model parameters are theoretically and practically identifiable with only a slight misestimation of error parameters affecting s judgments , something that does not hamper the estimation of the relevant parameters governing perception of temporal order ( a , v , , and ) . in any case , error rates are nuisance parameters that are known to be generally difficult to estimate accurately ( garca - prez and alcal - quintana , 2005 ) but it is also known that including them in the functions to be fitted increases the precision with which relevant parameters can be estimated ( see also garca - prez and alcal - quintana , 2010a , b , 2011 ) . actually , allowance for error or lapse parameters in model psychometric functions for binary tasks is routine practice in visual psychophysics ( kingdom and prins , 2010 ) , but not so much in psychoacoustics or in research on prior entry or perception of temporal order . more thorough studies of parameter recovery also involving alternative estimation methods should be carried out , but these lie beyond the scope of this paper . sj3 data can be described by independent - channels models when response errors are considered , as lack of monotonicity and parallelism results from these errors . lapses of attention , in turn , produce lack of parallelism but not lack of monotonicity . response errors are often made inadvertently and , then , can not be easily removed from the data . yet , the contaminating influence of lapses can be easily removed by allowing observers to abort trials in which they missed the stimuli , instead of forcing them to indicate a judgment that they could not possibly have made . implementing this feature in the response interface is highly recommendable . reinstating independent - channels models with their interpretable parameters will contribute to a more precise analysis of the effects of experimental manipulations in studies of prior entry or temporal recalibration . recourse to these models will also be useful in general studies on the perception of temporal order under different stimulus conditions ( see van eijk et al . , 2008 , 2010 ) and for the analysis of observed differences in performance across tasks ( i.e. , the ternary sj3 task considered here , its binary version sj2 in which observers only indicate whether presentation was simultaneous or sequential , and the temporal order judgment task toj in which observers are forced to respond af or vf without allowance for an s response ; see garca - prez and alcal - quintana , submitted ) . the model presented here emphasizes the distinction between unobservable judgments and observed responses , where the latter are not direct indicators of the former when response errors occur . evidence of response errors is conspicuous in empirical data and errors are likely to occur more often when reaction times are also measured , due to the pressure to respond quickly and the ternary nature of the task ( i.e. , observers have to be quick but without mistaking which of the three response keys they have to press to indicate their judgment ) . because response errors are not unlikely in these cases , fitting a model that allows for them is thus of outmost importance in these cases . user - friendly software packages ( in matlab and r ) are under development for fitting the model presented here to sj3 data ( alcal - quintana and garca - prez , submitted ) . the authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest . Output:	independent - channels models of perception of temporal order ( also referred to as threshold models or perceptual latency models ) have been ruled out because two formal properties of these models ( monotonicity and parallelism ) are not borne out by data from ternary tasks in which observers must judge whether stimulus a was presented before , after , or simultaneously with stimulus b. these models generally assume that observed responses are authentic indicators of unobservable judgments , but blinks , lapses of attention , or errors in pressing the response keys ( maybe , but not only , motivated by time pressure when reaction times are being recorded ) may make observers misreport their judgments or simply guess a response . we present an extension of independent - channels models that considers response errors and we show that the model produces psychometric functions that do not satisfy monotonicity and parallelism . the model is illustrated by fitting it to data from a published study in which the ternary task was used . the fitted functions describe very accurately the absence of monotonicity and parallelism shown by the data . these characteristics of empirical data are thus consistent with independent - channels models when response errors are taken into consideration . the implications of these results for the analysis and interpretation of temporal order judgment data are discussed .
PubmedSumm118882	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: meningiomas are the second most common intradural spinal tumors , accounting for 25% of all spinal tumors14 ) . being a slow growing and invariably benign tumor , it responds favorably to surgical excision . risk factors for the disease recurrence after surgical excision have been discussed in many literature7,8,9,14 ) . in this report , we describe a patient with intradural extramedullary spinal meningioma that recurred 16 years after the initial surgery . a 64-year - old woman presented with weakness in both lower limbs , which had gradually progressed over the previous 4 months , and difficulty in walking on admission . she had no sensory dysfunctions or visceral involvements , but had a surgical history ( the removal of thoracic spinal tumor ) for a similar episode of bilateral lower leg weakness 16 years ago ( fig . 1 ) . clinical examination revealed a tender linear scar extending from the c7 to t9 spinous process . neurological assessment revealed bilaterally increased muscle tone , associated with symmetrical paraparesis ( 3/5 ) . no sensory loss or bladder / bowel involvement was evident . magnetic resonance images revealed at tl and t2 ; godolinium enhanced image showed a well - enhanced tumor mass on the left side in the spinal canal and marked the compression of the spinal cord combined with compressive myelopathy ( fig . she underwent a second surgery at the same site and a pale yellowish tumor was excised . 3 ) , compared with previously transitional type ( microscopic examination showed nests or concentric whorls of menigothelilal cells revealing polygonal or oval cells with eosinophilic and indistinct bordered cytoplasm and round nuclei , also showing of frequent psammoma bodies in the center of the tumor whorls ) . after 2 weeks , she showed a slight improvement of motor power and was discharged . meningioma is a common type of tumor that accounts for 25 - 46% of spinal neoplasms8 ) . its prognosis is known to be favorable and the disease recurrence is also rare if the tumor is totally removed . in general , the reported rates of recurrence are ranged from 4% to 10%7,3,4,14 ) . furthermore , most results have been reported good functional outcomes in 74% to 85% of operated cases . however , cohen - gadol et al.1 ) reported that a recurrence rate was as high as 22% in younger patients with age less than 50 years old . this study result showed that younger patients with the disease recurrence had aggressive histology , more extradural extension and longer follow - up periods . therefore , younger age at the time of the first surgery could be a risk factor for recurrence in spinal meningioma . mirimanoff et al.8 ) reported that the recurrence free survival rates after total removal of meningioma during the follow - up periods of 5 , 10 and 15 years were 93% , 80% and 68% , respectively . after subtotal removal of meningioma , the progression free rates were reported to be 63% , 45% and 9% , respectively , for the same follow- up periods . the most common histological features of spinal meningioma include meningotheliomatous , fibroblastic , transitional and psammomatous . the other risk factors for the tumor recurrence are calcified meningioma and residual tumor remnants12 ) . in a previous study , it was reported that histologically classified psammomatous meningioma had a low risk of aggressive growth and recurrence11 ) . doita et al.2 ) reported a case of psammomatous type of spinal meningioma which recurred 33 years after the surgery . in this case , a calcified recurrent spinal tumor was detected on a plain radiograph at the same site after an initial operation and preoperative paraplegia improved after the surgery . nadkarni et al.9 ) reported a similar case as ours , which described a recurrence 18 years after the initial surgery . it may suggest that psammomatous histological type associated with calcification is a risk factor for recurrent spinal meningioma . our case was a histopathologically confirmed psammomatous meningioma which was a pathological variant most likely to be associated with calcification . moreover , the first operation revealed that the tumor was a histologically transitional type with frequent psammoma body in the center of the tumor whorls . therefore , contrary to the precedent reports in the literature , it is considered that psammomatous meningioma of our case have been transformed from the previous transitional type , of psammomatous types , to a calcification - associated psammomatous type when it recurred over the time . this suggests that the disease recurrence rate increases if histological calcification of meningioma is postoperatively manifested and if there are residual tumor remnants . this leads us to emphasize the importance postoperative histological re - examination to establish more active additional therapeutic strategies . spinal meningiomas were located laterally to the spinal cord or had a component that extended laterally . unlike intracranial meningiomas , there was no correlation between recurrence and the resection of dural attachment and locations4,5 ) . although extradural attachment of spinal meningioma has not yet been determined as a cause of recurrence , a variety of spinal meningioma is shown to increase the rates of recurrence13,14 ) . surgery is a preferred method in the treatment of spinal meningiomas owing to excellent functional improvements and low recurrence rates following surgery . our patient has not shown any worsening of neurological symptoms during the follow - up period . a marked neurological improvement after the second surgery in this case implies that it is possible to achieve favorable surgical outcomes in the treatment of recurrent meningiomas . we intend to highlight that the factors leading to the recurrence of meningiomas after surgery include young age , subtotal re- section of the lesion , calcification and extradural attachment . Output:	meningiomas are the second most common intradural spinal tumors accounting for 25% of all spinal tumors . being a slow growing and invariably benign tumor , it responds favorably to surgical excision . in addition , spinal meningioma has low recurrence rates . however , we experienced a case of intradural extramedullary spinal meningioma which recurred 16 years after the initial surgery on a 64-year - old woman . she presented with progressive neurological symptoms and had a surgical history of removal of thoracic spinal meningioma 16 years ago due to bilateral low leg weakness . she underwent a second operation at the same site and a pale yellowish tumor was excised , which was histopathologically confirmed as meningothelial meningioma , compared with previously transitional type . she showed neurological recovery after the operation . we , therefore , report the good results of this recurrent intradural spinal meningioma case developed after 16 years with literature review .
PubmedSumm118883	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: retroperitoneal laparoscopic ureterolithotomy ( rlu ) is recognized as a method that can replace open ureterolithotomy as a first - line treatment for large impacted upper or midureteral calculi and as a salvage treatment for use when ureteroscopic removal of stone ( urs ) or extracorporal shock wave lithotripsy ( eswl ) has failed . when rlu is used to treat stones larger than 1 cm , the stone - free rate reaches 100% , which confirms rlu as an effective minimally invasive treatment modality . some authors support the idea of deploying a double j ( d - j ) stent after the stone is removed to prevent urine leakage and ureteral stricture , but others do not agree because d - j stenting has shown no correlation with the complication rate and increases the number of inconveniences to the patient , such as lower urinary tract symptoms , pain , and cost of cystoscopic removal of the d - j stent . because of this controversy , in the present study , we assessed the need for ureteral stents after rlu . between june 2010 and january 2013 , rlu was performed by one surgeon in chonbuk national university hospital on 41 patients who had impacted upper ureteral stones larger than 1 cm and who had experienced unsuccessful eswl or urs . exclusion criteria included a positive urine culture , which is a conventional contraindication to surgery . before the operation , the age , gender , and body mass index of the patients and the results of their physical examinations and laboratory tests ( urinalysis , urine culture , and renal function test ) were obtained , as were their non - contrast computed tomography ( ct ) images . the kidney , ureter , and bladder x - ray , the postoperative laboratory test results , and the physical examination results 1 week and 3 months after discharge were reviewed , and additional imaging studies were performed when needed . of the total 41 patients , the first 17 patients received d - j stents and the next 24 patients did not . thus , the stent group consisted of patients in whom a d - j stent was placed and the stentless group consisted of patients treated without a d - j stent . the surgery was performed with the patient under general anesthesia . with the patient in the lateral position , a 1-cm skin incision was made at the umbilicus level on the midaxillary line , and blunt dissection was performed on the muscle and the dorsolumbar fascia by using straight kelly forceps . a retroperitoneal space was made by using a lubricated index finger , and additional space was secured by using an air balloon dilator . a 10-mm camera port was inserted and two 5-mm ports were inserted under direct vision . using co2 gas , the surgery was performed in the following order : ureter identification , minimum dissection of ureter , confirmation of the stone location , longitudinal incision of the proximal ureteral area of the bulge caused by the stone by use of a cold knife ( because it results in less inflammation of the tissue and less injury to the vasculature ) , stone extraction by use of a right - angled clamp , meticulous interrupted intracorporeal suture of the incised ureter by use of vicryl 5 - 0 , 5-mm camera insertion and stone removal through the 10-mm port , and placement of a drain via a 5-mm port . baseline characteristics , operation time , stone - free status , blood loss , drain removal , and postoperative complications of the two groups were analyzed . the data were analyzed by using the mann - whitney test and a p - value < 0.05 was considered statistically significant . between june 2010 and january 2013 , rlu was performed by one surgeon in chonbuk national university hospital on 41 patients who had impacted upper ureteral stones larger than 1 cm and who had experienced unsuccessful eswl or urs . exclusion criteria included a positive urine culture , which is a conventional contraindication to surgery . before the operation , the age , gender , and body mass index of the patients and the results of their physical examinations and laboratory tests ( urinalysis , urine culture , and renal function test ) were obtained , as were their non - contrast computed tomography ( ct ) images . the kidney , ureter , and bladder x - ray , the postoperative laboratory test results , and the physical examination results 1 week and 3 months after discharge were reviewed , and additional imaging studies were performed when needed . of the total 41 patients , the first 17 patients received d - j stents and the next 24 patients did not . thus , the stent group consisted of patients in whom a d - j stent was placed and the stentless group consisted of patients treated without a d - j stent . the surgery was performed with the patient under general anesthesia . with the patient in the lateral position , a 1-cm skin incision was made at the umbilicus level on the midaxillary line , and blunt dissection was performed on the muscle and the dorsolumbar fascia by using straight kelly forceps . a retroperitoneal space was made by using a lubricated index finger , and additional space was secured by using an air balloon dilator . a 10-mm camera port was inserted and two 5-mm ports were inserted under direct vision . using co2 gas , pneumoperitoneum was maintained at a pressure of 11 to 13 mmhg . the surgery was performed in the following order : ureter identification , minimum dissection of ureter , confirmation of the stone location , longitudinal incision of the proximal ureteral area of the bulge caused by the stone by use of a cold knife ( because it results in less inflammation of the tissue and less injury to the vasculature ) , stone extraction by use of a right - angled clamp , meticulous interrupted intracorporeal suture of the incised ureter by use of vicryl 5 - 0 , 5-mm camera insertion and stone removal through the 10-mm port , and placement of a drain via a 5-mm port . baseline characteristics , operation time , stone - free status , blood loss , drain removal , and postoperative complications of the two groups were analyzed . the data were analyzed by using the mann - whitney test and a p - value < 0.05 was considered statistically significant . the mean age of the patients , serum creatinine level , and stone size ( stent group , 17.64 mm ; stentless group , 18.26 mm ) were not significantly different between the two groups . nine patients had a history of eswl , and three had a history of urs . the retroperitoneal approach was used in all patients by a single surgeon . of the total 41 patients , the first 17 patients received a d - j stent and the next 24 patients did not . the mean operative time was significantly shorter in the stentless group than in the stent group ( 59.48 minutes vs. 77.88 minutes , p<0.001 ) . parenteral analgesic use and anticholinergic medication were observed in the stent group only ( analgesics , 3 patients ; anticholinergics , 2 patients ) . the mean blood loss , mean hospital stay , and mean drain removal day were not significantly different between the two groups . the stone - free rate was 100% , and no case was converted to open surgery . no other complications , such as blood transfusion , febrile urinary tract infection , wound infection , or paralytic ileus , were reported . the intra- and postoperative data of the subjects are shown in table 2 . at the 1-week and 3-month follow - up , the non - enhanced ct images of the eight patients showed no findings of hydroureteronephrosis or ureteral stricture . at the next follow - up , the patients ' symptoms had spontaneously disappeared . less invasive laparoscopic ureterolithotomy ( lu ) has been recognized as the first - line treatment for 1.5-cm or larger upper or midimpacted ureteral stones and as a salvage treatment for unsuccessful urs and eswl . when a skilled surgeon performs lu for a 1-cm or larger upper ureteral stone , the stone - free rate reaches 100% , as it did in this study . compared with the transperitoneal approach , the retroperitoneal approach is reported to have better outcomes in terms of pain , ileus , port site hernia , and hospital stay . nevertheless , when the transperitoneal approach was used , a larger working space could be secured and the anatomical landmark could be easily confirmed , unlike in the retroperitoneal approach . upon consideration of the location of the ureteral stone and its anatomical relationship , the method of approach we believe that selection of the approach before the lu results in a shorter operative time and an enhanced success rate . there is no definite answer to the question of whether a need exists to place a d - j stent after lu . a group of surgeons support the idea of placement of the d - j stent to prevent urine from leaking , but another group recommends that a stent not be used and instead that solely intracorporeal suturing be performed . karami et al . compared the cases in which a d - j stent was used with those in which it was not used and reported that the use of the d - j stent significantly decreased the development of complications without extending the operative time . accordingly , they supported the placement of a stent . however , hammady et al . compared a stent group with a stentless group and reported that the stentless group asked for a lower dose of analgesics and that their operative time was shorter and more economical without an increase in complications compared with the stent group . kijvikai and patcharatrakul suggested the use of the d - j stent only in cases of severe ureteral inflammation in which ureteral sutures can not be performed . in 2011 , we decided to start to perform rlu without d - j stenting according to the results of this study . however , we have not experienced a case in which suturing could not be performed because of severe ureteral inflammation . recommended the use of a cold knife to make an incision on the ureter to prevent ureteral strictures . by contrast , other groups have suggested that an electric hook is easier to use in ureterotomy than a cold knife and does not cause any problems . we thought that the use of the electric hook would not be absolutely free from the ischemic damage caused by capillary injury nor from direct tissue damage ; thus , we used the cold knife for the longitudinal ureterotomy . many surgeons have performed ureterotomy directly on the site of the bulge of the ureter , but we used a cold knife to make a longitudinal incision of the proximal ureteral bulge caused by the stone . in most cases we thought that when the bulge was incised , suturing might be difficult , the possibility of recovery after the suturing might decrease , and the possibility of ureteral stricture due to adhesion at the suture site would increase . the process of removing the stone by use of a right - angle clamp after incising the proximal ureter of the area of the bulge with a cold knife was not difficult . comparative studies on the development of complications in cases that involved the use of a cold knife versus an electric hook , and of bulge site ureterotomy versus non - bulge - site ureterotomy , may be needed in the future . the limitations of our study included the lack of an imaging study such as ultrasonography or ct scans to confirm ureteral strictures in all the subjects ; these were only performed on the eight patients who complained of mild flank discomfort at the follow - up . selective imaging studies were conducted because no patient had a significantly increased serum creatinine level after surgery and because of the high cost and the risk of radiation exposure of the imaging study . another limitation was the short follow - up period ; the shortest case was 5 months . although the most extensive period of development of ureteral stricture after lu was not clearly investigated , the follow - up period in this study is considered short . in the future , long - term and large - scale studies may be needed . through this study , rlu was reconfirmed as a safe , effective , and minimally invasive treatment method for large stones or for cases of unsuccessful treatment with other methods . in this study , no complications such as urine leakage or ureteral stricture developed when the d - j stent was not used . we believe that laparoscopic ureteral stone surgery without d - j stenting is safe , economical , and less inconvenient for patients . in the future , large - scale studies that are focused on the development of complications , such as urine leakage and ureteral stricture , according to the surgical technique may be needed . Output:	purposethere is some debate over the necessity of ureteral stenting after laparoscopic ureterolithotomy . we evaluated the need for ureteral stenting after retroperitoneal laparoscopic ureterolithotomy ( rlu).materials and methodsbetween january 2009 and january 2013 , 41 patients underwent rlu to remove upper ureteral stones . the retroperitoneal approach was used in all patients by a single surgeon . a double j ( d - j ) stent was placed in the first 17 patients after the procedure but not in any of the next 24 patients.resultsthe mean patient age , serum creatinine levels , and stone size were not significantly different between the two groups . the stone - free rate was 100% . the mean operative time was significantly shorter in the stentless group than in the stent group ( 59.48 minutes vs. 77.88 minutes , p<0.001 ) . parenteral analgesic use and anticholinergic medication use were observed in the stent group only . the blood loss , drain removal day , and hospital stay were not significantly different between the two groups . no other significant complications occurred during or after the operation in any patients.conclusionsrlu is a safe and effective treatment modality for large impacted ureteral stones . in this study , d - j stent placement was not necessary after rlu . in the future , large - scale studies of rlu without d - j stenting , especially on the frequency of the development of complications according to the surgical technique , may be needed .
PubmedSumm118884	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: el albinismo constituye una amenaza significativa para las funciones visuales , y causa una morbilidad ocular considerable que deriva a menudo en discapacidades visuales . el objetivo del estudio fue la descripcin de la condicin visual de los pacientes con diagnstico de albinismo oculocutneo completo ( oca ) , en un hospital ocular terciario de nepal . este es un estudio transversal y descriptivo llevado a cabo en mbito hospitalario , que incluy a todos los casos diagnosticados de albinismo oculocutneo ( 16 varones y 9 mujeres ; edad media , 16 aos ) que visitaron el departamento de oftalmologa del instituto de medicina para realizar una revisin ocular entre el 1 de septiembre de 2011 y el 1 de diciembre de 2013 . todos los participantes tenan agudeza visual mximamente reducida ( media : 1,240,50 logmar ) . considerando el equivalente esfrico , la mayora de los ojos ( n=30 ; 60% ) tenan miopa , con un valor medio de -1,595,39 d. la agudeza visual mejor considerablemente con la realizacin de la correccin refractiva ( prueba de t de la muestra pareada , p<0,05 ) . el nistagmo pendular horizontal fue el nistagmo ms comn ( n=34 ojos ; 68% ) . la esotropa alternante y la exotropa alternante se observaron cada una en el 16% de los casos con estrabismo ( el 40% de los casos ) . los pacientes con oca presentan un amplio espectro de dficits visuales que afectan a la funcin visual . la mejora considerable de la agudeza visual tras la correccin ptica sirve de estmulo para reducir las discapacidades visuales en los individuos con albinismo . albinism is a genetic disorder involving defective melanin biosynthesis , attributed to an inborn error of metabolism . a defective synthesis of melanin from tyrosine or its absence resulting from the mutation of one or more associated genes causes albinism . the consequence of such mutations is a reduction or absence of melanin in various parts of the body , particularly hair , skin and eyes . its frequency is estimated to be approximately one in 20,000 . on account of its autosomal recessive inheritance pattern in most cases , males and females are often equally affected.3 , 4 varying degrees of hypopigmentation occur due to different mutation types , which give rise to phenotypic heterogeneity . oculocutaneous albinism succinctly implies reduction ( incomplete oca ) or absence ( complete oca ) of melanin in the eyes , skin and hair , whereas ocular albinism entails the reduction or absence of melanin in the eyes only , with the melanocytic system offering normal pigmentation to the rest of the body . abnormal refractive profiles in patients with oca have been previously established , with high refractive errors , including high with - the rule astigmatism being frequently encountered . there has been a bias towards both hyperopia2 , 15 , 16 and myopia6 , 17 in various studies regarding the distribution of refractive errors . furthermore , oca has significant anatomical defects , such as large corneal astigmatism , foveal hypoplasia and abnormal decussation of optic nerve fibers . the abnormal decussation is due to reduced or absent melanin , which is thought to determine the neuronal target specificity in the brain . this occurs secondary to misrouting of retinogeniculate projections resulting in strabismus and reduced stereoscopic vision.3 , 4 , 7 consequently , visual acuity is generally reduced , leading to visual impairment , and cases tend to have severe photophobia as a consequence of ocular hypopigmentation . in addition , nystagmus and color vision impairment tend to occur frequently in patients with oca . although the condition is rare , it is potentially blinding because of its strong association with higher amounts of refractive error , especially corneal astigmatism , intra - ocular light scatter , light - induced retinal damage , and a partially or un - differentiated fovea . it is highly important that refractive errors and poorer visual acuity presenting from an early age be detected and managed appropriately . in the asian literature , there is a paucity of data on the vision and refractive status of patients with oca . optometric care can help albinotic cases enhance their visual performance by improving their retinal image or training them to use their residual vision in the best possible way . as the first of its kind in nepal , the study documents the visual deficits present in a clinical population with oca and compares them with those observed in previous studies abroad . twenty - five consecutive cases ( 50 eyes ) diagnosed with complete oculocutaneous albinism were included in the study . koirala lions center for ophthalmic studies , institute of medicine between september 1 , 2011 and december 1 , 2013 . the study adhered to the tenets of the declaration of helsinki and written informed consent was obtained from all the participants . the diagnostic criteria for oculocutaneous albinism were the presence of iris transillumination , retinal hypopigmentation and depigmentation of the skin , hair , and nails.5 , 8 due to the absence of tyrosinase hair bulb incubation tests in the hospital , the participants were not further classified into tyrosinase positive or negative . a semi - structured questionnaire was designed to record the relevant history and clinical findings . the information extracted and the clinical evaluations completed were demographics ( age and sex ) , unaided and aided visual acuities by using the balie - lovie logmar illiterate and literate charts ( whichever appropriate ) , a case history of chief complaints , previous ocular examination and use of any refractive correction , objective refraction ( retinoscopy ) findings and subjective acceptance , a detailed examination of the anterior and posterior segments by using slit lamp biomicroscopy and fundus evaluation under mydriasis with auxiliary lenses , and assessment of extraocular motility , strabismus , color vision , stereopsis , nystagmus , null zone and head posture . cycloplegic refraction was carried out , in which cycloplegia was achieved upon the instillation of three drops of 1% cyclopentoalate ( cyclogyl ) 10 min apart . : grade i , normal iris pigmentation ; grade ii , reduced iris pigment with punctuate iris transillumination in visible locations ; grade iii , almost complete transillumination with the collarette having minimal pigment ; grade iv , completely unpigmented irides . also , the description of summers et al . was used to grade macular transparency : grade i , a transparent macula with easily visible choroidal vasculature ; grade ii , slightly obscured choroidal vasculature ; grade iii , an opaque macula with invisible choroidal vasculature . amblyopia was defined when there was reduced best corrected visual acuity or interocular difference in visual acuity in the presence of amblyogenic factors ( both functional and organic ) . the unilateral cover test was used to determine whether the participants were orthotropic or heterotropic . when the heterotropia was observed , its direction and magnitude were determined by using the alternate cover test while the krimsky test was used to find the magnitude of the manifest ocular deviation in the presence of poor fixation . the titmus fly stereotest was used to assess stereopsis , which was subsequently graded into the three groups , namely no stereopsis ( ns ) , coarse stereopsis ( cs ) and fine stereopsis ( fs ) ; nds group no stereoacuity , cs group no better than 140 of stereopsis and fs group at least 100 of stereopsis and the assessment was carried out with refractive correction , whenever appropriate . all the objective tests were carried out by an optometrist while the anterior and posterior segment findings were confirmed by an ophthalmologist . ametropia was classified into myopia , hyperopia , myopic astigmatism , hyperopic astigmatism and mixed astigmatism . astigmatism was further classified into with - the rule , against - the rule and oblique on the basis of the strongest and weakest meridian . visual function was classified into four levels , namely normal vision , moderate visual impairment , severe visual impairment and blindness , according to the international classification of disease-10 . low vision , comprising moderate and severe visual impairment together with blindness represented all types of visual impairment . the student 's t - test was used to determine the significance of the differences between the means of two groups and a pearson linear correlation coefficient was used to study the correlation ; p < 0.05 was considered statistically significant . twenty - five albinotic cases ( median age = 16 years ; interquartile range = 12 ) were included in the study . there were 16 males ( 64% ) and 9 females ( 36% ) , with a male : female sex ratio of 1.78 . the 514 and the 1423 age groups had an equal number of participants , 11 in each ( 44% ) , whereas the least number of participants ( n = 1 ) was in the 2332 age group ( table 1 ) . presenting distance visual acuity was > 1.30 logmar in 14 eyes ( 28% ) , > 1.00 logmar but 1.30 logmar in 16 eyes ( 32% ) , > 0.48 logmar but 1.00 logmar in 19 eyes ( 38% ) and 14 eyes were blind . mild visual impairment was observed in only one eye , with pva of 0.48 logmar , out of 50 eyes . after optical correction using glasses , six eyes ( 12% ) had mild visual impairment , 28 eyes ( 56% ) had va greater than 0.48 but 1.00 logmar ; 12 eyes ( 24% ) had va greater than 1.00 logmar , but 1.30 logmar , and four eyes ( 8% ) had va greater than 1.30 logmar ( table 2 ) . as per the world health organization classification based on best corrected distance visual acuity , 12% , 56% , 24% and 8% of 50 eyes had mild vi , moderate vi , severe vi and blindness respectively . there occurred a significant mean difference between uncorrected acuity ( mean acuity : 1.24 0.50 logmar ) and corrected acuity ( mean acuity : 1.0252 0.48 logmar ) ; t(49 ) = 4.91 , p < 0.0001 . a moderately positive correlation ( karl pearson linear correlation coefficient , r = 0.80 , p < 0.001 ) was obtained between uncorrected and corrected distance visual acuities ( table 3 ) . myopic astigmatism was most prevalent ( n = 17 , 34% ) , which was followed by mixed astigmatism ( n = 9 , 18% ) , and simple myopia ( n = 8) , simple hypermetropia ( n = 8) and hypermetropic astigmatism ( n = 8) each accounted for 16% of all refractive error ( table 4 ) . considering the spherical equivalent refractive error , 60% eyes were myopic and 40% eyes were hyperopic . all cases of astigmatism were the with - the - rule type except two cases , which had against - the - rule astigmatism . the astigmatic cylinder ranged from 0.50 diopters to 4.00 diopters , with a mean of 1.93 1.00 diopters . visual acuity improvement was noted in 27 eyes following the refractive correction , while 23 eyes demonstrated no change in distance visual acuity even after the correction . those whose visual acuity were reduced and remained statistically the same before and after the correction in the presence of amblyogenic factors ( functional and organic ) were diagnosed with amblyopia . very notable visual acuity improvement occurred when it reached 1.00 logmar and 0.48 logmar from 2.0 logmar and 1.48 logmar respectively . the eyes were divided into two groups based on the whether their acuity improved upon optical correction . group 1 ( g1 ) showed an improvement , while group 2 ( g2 ) did not . the participants in g1 had a mean age of 16.52 1.45 years , and a mean corrected distance visual acuity of 0.89 0.04 logmar . the participants in g2 had a mean age of 14.78 1.93 years , and a mean corrected distance visual acuity of 1.19 0.64 logmar ( table 5 ) . we could not single out any error type that showed best improvement statistically after the institution of an optical correction . nystagmus was present in 21 participants ( 84% ) , with horizontal pendular type ( n = 34 eyes , 68% ) being most common , followed by horizontal left jerky ( n = 6 , 12% ) and horizontal right jerky ( n = 2 ; 4% ) nystagmus ( fig . primary position ( n = 34 , 68% ) was the most common null point ( fig . right eye exotropia ( n = 1 ; 4% ) and left eye exotropia ( n = 1 ; 4% ) were the least common of all ( fig . fine stereopsis ( fs ) was observed in four participants ( 16% ) , coarse stereopsis ( cs ) in 8 participants ( 32% ) , and no detectable stereopsis ( nds ) in 13 participants ( 52% ) ( fig . all of the participants reported they had blurring of vision for both distance and near and experienced photophobia . foveal hypoplasia , iris diaphanous translucency and the absence of foveal reflex were universally present . the participants were also divided into three groups based on the stereopsis grading ( table 6 ) . the nds group consisted of 13 participants , the cs group consisted of 8 participants and the fs group consisted of 4 participants . as stereopsis improved , the visual acuity was seen to increase ; however , this increment in distance visual acuity was not of statistical significance ( one - way anova with post hoc tests , p = 0.66 ) . of the three groups , macular transparency was found to be least in the nds group ; the highest transparency was observed in the fs group , followed by the cs group . the mean difference in the macular transparency was not statistically significant whilst comparing the nds and cs groups , whereas the transparency difference was significant whilst comparing the nds and fs groups ( p = 0.010 ) , and comparing the cs and fs groups ( p = 0.04 ) . participants in the fs and cs groups exhibited a lower iris transillumination defect compared to those in the nds group . the mean iris transillumination grade in the nds group was the highest and differed significantly from that in the fs group ( p = 0.036 ) , whose mean also differed from that of the cs group ( p = 0.038 ) . color vision was normal in 19 participants ( 76% ) , while three participants ( 12% ) had a red - green color vision deficiency . in three participants ( 12% ) the magnitude of strabismus averaged 24.15 8.02 prism diopters ( magnitude interval , 1240 prism diopters ) . none of the participants were found to adopt a compensatory head posture to dampen nystagmus . individuals with oculocutaneous albinism have visual impairment that renders their social interactions compromised compared to their typical peers , hence encumbered cognitive , emotional , social and academic development . this makes them more prone to social isolation and greater stigmatization . as a result , they are caught in a vicious circle of the poor development and social ostracism . in the current study , that all the eyes had visual impairment with the majority ( 38% ) of them having moderate vi can be explained in part by higher refractive error that was amblyogenic and in part by other factors , such as hypoplastic foveae , squint , nystagmus , and photophobia ; this is consistent with the results by eball et al . who reported that the majority ( 70% ) of the eyes had moderate visual impairment . there have been reports in the literature that higher spherical and astigmatic refractive errors are associated with albinism.13 , 14 as both hypermetropia2 , 15 , 16 and myopia6 , 17 have been reported to be associated with albinism , this study also encountered both types even with higher magnitude refractive errors . in much the same way , this study found that 20% of all participants ( 5 participants , 10 eyes ) had refractive error greater than 10 d. this finding is also comparable to that obtained by perez - carpinell et al . who reported that 14% of the albinos had refractive error greater than 10 d. the participants in this study exhibited a refractive bias towards myopia ; the finding being distinct from wildsoet et al.s study which showed a bias towards hypermetropia . mvogo et al , in their study , reported the prevalence of 61.9% and eballe et al . observed that of 40% establishing myopic astigmatism to be the most common refractive error in albinos.12 , 19 this study also found the similar result in which 34% of the cases had myopic astigmatism making it the most prevalent refractive error in patients with oca . on the contrary , other studies reported hypermetropia to be the most common refractive error.2 , 15 , 16 because emmetropization is afflicted by large corneal astigmatism and a constant motion of the retinal image , large refractive errors ensue . in strong agreement with our study which obtained larger amounts of astigmatism , especially a with - the - rule type , the studies also maintain strong associations of albinism with with - the - rule astigmatism.2 , 12 , 15 refractive astigmatism thus seen is largely corneal in origin , in that the cornea is steeper along the vertical meridian compared to the horizontal meridian . the preferential curvature change along the vertical meridian is possibly due to the pressure exerted by the upper lid on the moving cornea.17 , 21 in this study , the mean pva was 1.24 logmar , while the same in the study by eball et al . had a mean pva of 0.96 logmar , which was expressed as a decimal value of 0.11 . the fact that significant improvement in visual acuity followed after refraction correction bears strong positive resemblance to the study by eball et al . , who also categorized all eyes in two groups : one group ( g1 ) which showed improvement and the other ( g2 ) that did not show improvement ; the ratio of the number of eyes in g1 to that in g2 was approximately 1.06 . binocular anomalous color vision was reported in 44% of cases in the study by perez - carpinell et al . in this study , binocular color vision was normal in 19 participants ( 76% ) , which represents a substantial percentage . misrouting of reticulate projections at the optic chiasm is attributed to melanin deficiency , causing strabismus which is frequent in albinism and therefore results in a lack of stereoscopic vision . a large angle kappa as high as 17.11 exo prism dioptres was observed in a study . in this study , the mean magnitude of strabismus was recorded at 24.15 8.02 prism diopters ( magnitude interval , 1240 prism diopters ) , which is significant . absence of nystagmus and strabismus correlated well with fine stereopsis , i.e. , there was no fine stereopsis if either nystagmus or strabismus or both were present and when either or both of them were absent , individuals possessed a stereoscopic vision . and also that visual acuity was greatest in the fs group suggests the role of nystagmus in the deterioration of visual acuity . this study is similar to the study by lee et al . which reported that the patients with fine stereopsis had better visual acuity . similar to the reports that nystagmus is invariably present in oca and that in most cases it is horizontal and pendular , this study had 84% of participants with nystagmus and 68% had a horizontal and pendular type.2 , 24 none of the participants assumed an abnormal head posture . it could be explained by the fact that there occurred no vertical misalignment and the participants had adapted to the straight - head posture . in addition , 17 participants ( 68% ) had the null zone in the primary position . also , as obtained in the study by lee et al . , who reported more melanin in the macula and the iris in albinism is associated with greater acuity and increased stereopsis , this study confirmed those findings . in relation to the fovea only , poor visual acuity can therefore be ascribed to less pigment as suggested by this study , and varied cone morphology and cone specialization . despite its low prevalence , albinism remarkably causes visual impairment , blindness , amblyopia and challenges an educational environment , all leading to educational retardation ; therefore , optometric care must be administered with refractive optical correction which incorporates filters to lessen or eliminate photophobia and prisms to eliminate abnormal head postures , if any , at their very early age so as to prevent them from stigmatization related to poor development and impairment.12 , 26 , 27 in light of a significant role that optometrists can play in the rehabilitation of the individuals with albinism and improving their quality of life , it is high time other health care professionals started referring albinos for optometric intervention in the form of refractive correction and low vision rehabilitation . the fact that the 514 and 1423 age groups each had 44% of all participants ( the highest compared to any other age group ) illustrates that oculocutaneous albinos seek medical attention as early as possible in their lives because it is a congenital and visually impairing condition , which limits a child 's overall development ; a greater number of males in this study could be suggestive of easier access to health care by males than females , who are still unjustly treated , because of nepal 's patriarchal societies which view females as subordinate to males . due to small sample size however , small sample size signifies the rarity of condition in nepal and the lack of appropriate referrals for low vision examination . despite a small sample size , the present study effectively presents the gravity of the visual deficits found in oculocutaneous albinism and attempts to apprise the concerned authority of the burden , and also calls for planning and advocacy of appropriate optometric care essential for visually impaired people living with albinism in nepal and abroad . in low - income countries like nepal where disability care is often not a priority , this study helps mark an important milestone for more optometric care . the ultimate aim of this study is to increase awareness and improve vision care and intervention for albinism cases . in addition , this study provides a baseline for possible prospective research in the future , including studies on visual deficits in albinism by oca sub - types . as a result of various factors associated with oculocutaneous albinism , visual performance can be greatly enhanced by instituting appropriate optical treatment following cycloplegic refraction performed by optometrists . optical treatment is a blend of refractive correction and photophobia alleviation with appropriate lenses and filters . since albinism has strong associations with higher refractive error and ocular pathologies , the likelihood of occurrence of amblyopia ( both functional and organic ) increases , whose severity becomes likely to be reduced , if not effaced , provided refractive intervention is done early in life . this study warrants adequate optometric interventions to help care for oculocutaneous albinos because 54% of all participants significantly improved their acuity with refractive correction . albinism is a condition , but carries a spectrum of other deficits which necessitate optometric care , which is possible by increased public awareness and appropriate referral . Output:	backgroundalbinism poses a significant threat to visual functions and causes remarkable ocular morbidity often resulting in visual disabilities . the study aimed at describing the visual status in patients with diagnosed cases of complete oculocutaneous albinism ( oca ) attending to a tertiary eye hospital in nepal.methodsthis was a cross - sectional descriptive hospital - based study of all diagnosed oculocutaneous albinotic cases ( 16 males and 9 females ; mean age of 16 years ) who visited the department of ophthalmology at the institute of medicine , for ocular consultation between september 1 , 2011 and december 1 , 2013.resultstwenty-five cases ( 50 eyes ) with oca were enrolled in the study . all the participants had maximally reduced visual acuity ( mean : 1.24 0.50 logmar ) . myopic astigmatism was the most common refractive error ( n = 17 ; 34% ) . 58% of all participants had with - the - rule astigmatism.considering the spherical equivalent power , most of the eyes ( n = 30 ; 60% ) had myopia , with overall mean se refractive error of 1.59 5.39 d. visual acuity improved significantly with refractive correction in place ( paired sample t - test , p < 0.05 ) . horizontal pendular nystagmus was the most common nystagmus ( n = 34 eyes ; 68% ) . alternating esotropia and alternating exotropia each were observed in 16% of participants who had strabismus ( 40% of all cases ) . the diaphanous iris , foveal hypoplasia and poliosis were the most consistent clinical features.conclusionpatients with oca present with a broad spectrum of visual deficits that impair the visual functions . significant improvement in visual acuity following optical correction serves as an impetus to the reduction of visual disabilities in individuals with albinism .
PubmedSumm118885	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: it the most common solid pelvic tumor , affecting 2025% of reproductive - aged women , of whom 50% are symptomatic . the severity of symptoms associated with uterine leiomyoma depends on the number , size , and location of the tumor . the most common symptoms leading to treatment are abnormal uterine bleeding , pelvic pain and pressure . risk factors include increased estrogen stimulation including controlled ovarian stimulation , family history of uterine fibroid tumor , and race . growth hormone and human placental lactogen have also been shown to be major growth regulators of myomas . leiomyoma is seldom the sole cause of infertility , but data from several studies have demonstrated a link between fibroid tumors , fetal growth restriction , and premature delivery . symptomatic leiomyoma is also a significant cause of hospitalization , high annual health costs , absence from work , and morbidity in women aged 1554 years . approximately 510% of patients with infertility have uterine fibroid tumors and are not a candidate for hormonal therapy , leaving myomectomy as the main option . endometriosis is also a common gynecologic condition , affecting 1050% of reproductive - aged women . . its prevalence can be as high as 40% in infertile women and up to 87% in women with chronic pelvic pain . there has also been concern regarding the association between endometriosis and malignancy specifically ovarian cancer . patients with endometriosis also face the burden of high health costs before and after proper diagnosis . the coexistence rate of endometriosis and leiomyoma continues to be poorly understood , as few studies have investigated the association . dismissing the diagnosis of endometriosis during surgical intervention for fibroid tumors , can result in suboptimal treatment , especially in patients with chronic pelvic pain , infertility , or both . the purpose of our study was to investigate the incidence of coexisting endometriosis in patients undergoing surgical treatment for symptomatic uterine fibroid tumors without a known history of endometriosis . this study was a retrospective analysis of data collected from all patients who presented to the center for special minimally invasive and robotic surgery ( palo alto , california , usa ) , a tertiary referral center for endometriosis , uterine fibroid tumors , infertility , and pelvic pain . patients who were referred to the center for the specific treatment of leiomyoma from march 2011 through december 2015 with complaints of symptomatic uterine fibroids without a previous diagnosis of endometriosis were included in the study . a total of 244 women with a chief concern of symptomatic leiomyoma with abnormal uterine bleeding without a prior diagnosis of endometriosis met inclusion criteria . patients with fibroid tumors who also had a diagnosis of infertility and pelvic pain were included if they also had concomitant abnormal uterine bleeding . at our institution , endometrial biopsy , magnetic resonance imaging , and lactate dehydrogenase levels are routinely performed on all patients with symptomatic fibroid tumors before undergoing surgery because of the recent controversy over leiomyosarcoma . patients reporting menorrhagia or irregular bleeding underwent preoperative endometrial biopsy or diagnostic / operative hysteroscopy before myomectomy . all patients with a complaint of infertility had chromopertubation performed at the time of surgery . tissue extraction was accomplished through extracorporeal morcellation , vaginally or via minilaparotomy . because information was obtained from the records in such a manner that human subjects could not be identified directly or through the identifier linked to the subjects , institutional review board approval was not necessary and a deidentifiable database was maintained . of the 244 patients who met the criteria , the remaining 208 patients underwent laparoscopic myomectomy ( with or without robot assistance ) , laparoscopic - assisted myomectomy , or laparoscopic hysterectomy . in all patients , the indication for surgery was bleeding , infertility , and pain . demographic data such as age , parity , and fertility history were collected from patients ' medical records ( tables 1 and 2 ) . patients who were scheduled for myomectomy / hysterectomy were also asked to consent to treatment of endometriosis in the event of intraoperative diagnosis . characteristics of patients with uterine fibroids and associated coexisting extrauterine endometriosis vs adenomyosis alone patient characteristics associated with mild and severe endometriosis the advancement of the improved endoscopic camera and monitor technology allows for more detailed visualization of endometriotic lesions . lesions that raise concern for endometriosis seen on laparoscopic survey were removed and confirmed by histologic examination of targeted biopsies . the revised american society of reproductive medicine classification of endometriosis was used to assess for severity of disease , which was classified as minimal ( stage 1 ) , mild ( stage 2 ) , or moderate ( stage 3 ) to severe ( stage 4 ) . all reported p - values are 2 sided , so both directions of alpha were tested for statistical significance ; p < .05 was statistically significant . a total of 208 patients underwent surgical treatment for symptomatic uterine fibroid tumors during the study period . most patients underwent laparoscopic or laparoscopic - assisted myomectomy ( 71.6% ) compared with hysterectomy ( 28.3% ) . the chief concern of all patients was abnormal uterine bleeding , with 84% of the study population also reporting pelvic pain ; 20.7% reporting infertility ; 20.7% reporting dyspareunia ; 21.2% reporting urinary symptoms including frequency , urgency , and dysuria ; and 21.2% reporting gastrointestinal symptoms , including dyschezia and alternating constipation and diarrhea during menses . 181 ( 87.1% ) had endometriosis noted at the time of surgery and subsequently confirmed by histology . of the 27 patients where endometriosis was not noted at the time of laparoscopic survey , 9 had adenomyosis on the final histology report . only 18 patients ( 8.6% ) were diagnosed solely with uterine fibroids after surgical evaluation . a total of 124 patients had a large fibroid tumor weighing more than 100 g , and of those , 107 ( 86.2% ) had associated endometriosis on the pathology report . the average weight of the fibroids was 381 g , with the weights ranging from 19.9 to 3000 g. this average and range are based on 160 patients ' pathologies , as 48 pathology reports did not include the weights of the tumor . concomitant diagnosis of endometriosis was noted in 181 of the 208 ( 87% ) patients and 93 of those ( 51.3% ) had moderate to severe disease ( stage 3 and 4 ) . of the patients who reported dyspareunia , urinary symptoms , and gastrointestinal symptoms , patients who had concomitant leiomyoma and endometriosis were on average 4.0 years younger than patients with leiomyoma alone ( 40.7 vs 44.5 ; p = .036 ; table 1 ) . patients between the ages of 30 and 39 had a 56% prevalence of endometriosis , occurring in 40% of those 4049 years of age and in only 0.038% of women aged 50 and older . in our cohort , we had 3 patients above 60 years of age , and none of them had endometriosis at the time of surgery or on their final pathology specimens . of the patients with a concomitant diagnosis of both fibroid tumor and endometriosis , 71.7% had more pronounced pelvic pain when compared with the fibroid - only group ( p = .001 ) . nulliparous patients were also more likely to be simultaneously diagnosed with both endometriosis and fibroid tumor than with fibroid tumor alone ( p = .005 ) . similarly , infertile women were more likely to have both diagnoses ( p = .08 ) , although these differences did not reach significance . we compared patients with mild ( stage 1 and 2 ) endometriosis with those with severe ( stage 3 and 4 ) endometriosis . patients with smaller fibroid tumors , ( < 4 cm or < 100 g in weight ) , were significantly more likely to have severe endometriosis than those with larger fibroid tumors ( p = .0009 ; table 2 ) . there was no significant difference in abnormal uterine bleeding , pain , nulliparity , and infertility between the 2 groups . from our cohort of 208 women , the first was an incidental cystotomy repaired laparoscopically during total laparoscopic hysterectomy in a patient with stage 4 endometriosis , extensive adhesions , and a fibroid uterus weighing 606 g on final pathology report . the second patient had a vaginal cuff hematoma after total laparoscopic hysterectomy for stage 4 endometriosis , extensive adhesions , and a 122-g fibroid uterus . an incision and drainage of the vaginal cuff was performed , and the patient recovered well . the last complication involved a patient who required a postoperative blood transfusion after laparoscopic - assisted myomectomy for a 3000-g fibroid uterus . no endometriosis was noted at the time of the laparoscopic survey , but the final pathology reported revealed adenomyosis . it is estimated that 25% of women over the age of 36 have 1 or more leiomyomas , with 50% of these being symptomatic . our study shows that it is possible for women to have both of these conditions at the time of surgery , emphasizing the importance of keeping a broad differential both before and during surgery . should endometriotic lesions be overlooked at the time of surgical treatment for fibroid tumors , treatment of pain may be suboptimal . both conditions are estrogen - dependent , which is congruent with our observation that endometriosis had increased prevalence in a younger patient population . this finding is consistent with previous studies associating younger age , higher estrogen levels , and increased prevalence of disease during reproductive years and improvement after menopause . the goal of our study was to assess the prevalence of endometriosis in our patient population with symptomatic leiomyoma as defined by abnormal uterine bleeding . strengths of the study include a single senior surgeon with decades of experience performing all surgeries , which decreased the inconsistency in diagnosis of endometriosis between surgeons at the time of laparoscopy . in addition to its retrospective design , a limitation to our study is that we are a tertiary referral center specializing in the treatment of endometriosis which introduces a potential population bias . we would expect the incidence of endometriosis in our patient population to be higher than that of the general population . however , given that we found that most of our patients had concomitant endometriosis at the time of surgery for treatment of uterine fibroid tumor , we believe that this association deserves further investigation . the current literature reports an incidence of concomitant fibroids and endometriosis ranging between 12 and 20% , based on 2 previously published studies . the first was a large multicenter study conducted in italy involving more than 3600 patients , 735 of whom had an indication for surgery that did not include fibroid tumor or pain . the second study was performed in finland and included 605 participants , 183 of whom underwent tubal ligation for sterilization . our study limited inclusion of patients to those with fibroid tumor and complaints of abnormal uterine bleeding . tanmahasamut et al diagnosed endometriosis by pathology report or visual inspection , not necessarily both . thus , it is possible that endometriotic lesions were miscategorized or missed altogether at the time of surgery . our study required the diagnosis of endometriosis to be made by both laparoscopic survey and pathologic confirmation , and our observed incidence of coexisting fibroid tumor and endometriosis was significantly higher than that reported in the current literature . based on these preliminary findings , we believe that in a subset of patients with symptomatic fibroid tumors and pelvic pain , endometriosis must be seriously considered as a concomitant diagnosis and may be more common than previously thought . because of the multifaceted nature of this disease , endometriosis is often called the great masquerader or the chameleon of the pelvis , as lesions are easily overlooked . it is especially possible to miss it by laparotomy , because one may not be able to completely visualize the posterior cul - de - sac , ovarian fossa , and broad ligaments in great detail . it is well recognized that optimal visualization provided by laparoscopy enhances diagnosis of the disease . in our study , thorough and systematic visual inspection was performed , and all possible lesions were biopsied , with histology - proven disease described in the cohort . it is possible that our higher incidence of coexisting disease found at the time of fibroid treatment was due to our high index of suspicion for endometriosis , which led to a careful and methodical survey of the abdomen and pelvis . there was no significant difference in the prevalence of minimal / mild and moderate / severe endometriosis in our cohort of patients with symptomatic fibroid tumors . although one might expect stage 1 and 2 disease to be more common in all women , including women with fibroid tumors , it is possible that these patients first explored medical therapy , which would delay their diagnosis and allow progression of the endometriosis . in addition , specifically for the subset of patients with fibroid tumors undergoing infertility treatment , controlled ovarian stimulation can worsen endometriosis as well . all except 1 of our patients with infertility and symptomatic fibroid tumors were found to have endometriosis as well . in addition , nulliparous patients were more likely to be simultaneously diagnosed with the 2 pathologies , which is consistent with the current literature , as the relationship between endometriosis and subfertility has been well documented . there is a reduced monthly fecundity rate ( 210% ) in patients with endometriosis , as compared with fertile couples ( 1520% ) . there is also an increased monthly fecundity rate and cumulative pregnancy rate after surgical removal of stage 1 and 2 endometriosis . we were surprised to find that in our study population , women with smaller fibroid tumors had more severe ( stage 3 and 4 ) endometriosis . one potential explanation is that women who have only fibroid tumors may be able to avoid surgical intervention until the tumor reaches a critical mass where the bleeding and pressure symptoms become unbearable . however , women who have severe endometriosis may have severe pain in addition to bothersome abnormal uterine bleeding that leads them to undergo surgery sooner as compared to their fibroid - only counterparts . based on the prevalence of myomas ( 1:5 ) , roughly more than 700 million women will have a fibroid tumor during their reproductive years . our preliminary results suggest that the incidence of endometriosis in these women is higher than currently reported in the literature . presently , there is a paucity of information describing the coexistence between the 2 pathologies . prospective studies evaluating for endometriosis at the time of surgery for uterine fibroids are currently lacking and constitute an area for further future investigation . our findings demonstrate that patients who have symptomatic leiomyoma may be at higher risk for endometriosis as well . because of the significant overlap of symptoms , it is often difficult to discern which pathology is responsible for the patient 's complaints . this highlights the importance of maintaining a high level of suspicion for endometriosis before and during surgery in these women , with the goal of treating both pathologies in a single surgery . one should be especially mindful of young patients who present with uterine fibroid tumors , abnormal uterine bleeding , and subfertility or nulliparity and those who present with pain disproportionate to the size of the tumor . failure to diagnose and treat can lead to continued pain , subfertility , and need for reoperation . Output:	background and objectives : the relationship between leiomyoma and endometriosis is poorly understood . both contribute to considerable pain and may cause subfertility or infertility in women . we conducted this retrospective study to assess the rate of coexistence of endometriosis in women with symptomatic leiomyoma . the primary outcome measured was the coexistence of histology - proven endometriosis in women with symptomatic leiomyoma.methods:this is a retrospective review of a data - based collection of medical records of 244 patients treated at a tertiary medical center , who were evaluated for symptomatic leiomyoma from march 2011 through december 2015 . of those , 208 patients underwent laparoscopic or laparoscopic - assisted myomectomy or hysterectomy . all patients provided consent for possible concomitant diagnosis and treatment of endometriosis . the remaining 36 patients underwent medical therapy and were excluded from the study . all patients who had myomectomy or supracervical hysterectomy underwent minilaparotomy for extracorporeal morcellation and specimen removal beginning in april 2012.results:of the 208 patients with the presenting chief concern of symptomatic leiomyoma and who underwent surgical therapy , 181 had concomitant diagnoses of leiomyoma and endometriosis , whereas 27 had leiomyoma . of the 27 patients , 9 also had adenomyosis . patients with only fibroid tumors were , on average , 4.0 years older than those with endometriosis and fibroids ( mean age , 44 vs 40 sd ) . patients with both pathologies were also more likely to present with pelvic pain and nulliparity than those with fibroid tumors alone.conclusions:in our patient population , 87.1% of patients with a chief concern of symptomatic fibroids also had a diagnosis of histology - proven endometriosis , which affirms the need for concomitant diagnosis and intraoperative treatment of both conditions . overlooking the coexistence of endometriosis in women with symptomatic leiomyoma may lead to suboptimal treatment of fertility and persistent pelvic pain . it is important for physicians to be aware of the possibility of this association and to thoroughly evaluate the abdomen and pelvis for endometriosis at the time of myomectomy or hysterectomy in an effort to avoid the need for reoperation .
PubmedSumm118886	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: this is principally based on the chemical characteristics of oxygen ; a series of reductions by one electron each is possible four times , until the oxygen is reduced to a stable species and solvent , h2o ( fig . 1 ) this characteristic enables efficient electron flow that is essential for any moving material , including motors and robots . during this electron flow , three intermediate species are generated , among which hydroxyl radical ( oh ) has been identified as the most damaging to biomolecules . accordingly , cells strategically prevent the generation of oh by metabolizing h2o2 directly into h2o via various types of enzymes , including catalase , peroxidases and peroxiredoxins . the roles of o2 and h2o2 as signaling molecules have been well established by studies within the past two decades . the adverse effects of oxygen were already recognized in the 1950 s , and oxygen free radicals were hypothesized to be the direct cause of aging . cancer has been the leading cause of death in japan for 30 years , while in most western countries , coronary heart disease is the current leading cause of death . i suspect that cancer would become the predominant cause of death in western countries as well if metabolic syndrome could be overcome by proper preventive exercise and diet . the longer we live , the more genetic alterations we obtain through persistent oxygen consumption and environmental exposure to genotoxic agents . thus , exposure to atomic bomb radiation in hiroshima and nagasaki was shown to increase leukemia and lymphoma , and ultraviolet radiation has been closely associated with skin cancer . chronic helicobacter pylori infection is associated with gastric cancer and low - grade lymphoma of mucosa - associated lymphoid tissue . similarly , inflammatory bowel diseases such as crohn s disease and ulcerative colitis are associated with colon cancer . in these cases , inflammation causes pain and various other symptoms , and x - radiation is currently under strict legal regulation . iron overload per se does not induce inflammation , nor is it under legal control . although the pathology of iron overload is really insidious , it can eventually lead to cancer . in this sense , iron deficiency causes anemia , but excess iron can be a risk for carcinogenesis because iron works as a catalyst for the fenton reaction , thus promoting the generation of the undesirable molecule , oh ( fig . 1 ) . iron stores within the body accumulate insidiously with aging because iron intake exceeds loss and no biologic mechanisms exist for excretion of iron in excess of physiological requirements . it was initially reported in 2008 that iron reduction by phlebotomy not only decreased visceral cancer risk by 35% but also decreased mortality in cancer patients by 60% in a supposedly normal population with peripheral arterial disease . in spite of some criticisms regarding design of this study , this is a highly significant observation supporting other epidemiological studies and one should not underestimate the role of iron in carcinogenesis . there are ample human epidemiological data to support the involvement of excessive iron in carcinogenesis . genetic hemochromatosis is a hereditary disorder of iron sensing and currently 4 genetic types are recognized . among them a mutation in the gene encoding slc40a1 ( omim # 606069 ) is associated with an autosomal - dominant type of hemochromatosis . it is of note that defects in hamp ( omim # 602390 ) or in transferrin receptor 2 ( omim # 604250 ) also induce hemochromatosis . major causes of death today in hereditary hemochromatosis are due to either hepatic failure with cirrhosis or hepatocellular carcinoma . in addition , hemochromatosis patients were shown to have 240-fold greater risk developing primary hepatocellular carcinoma than the age - matched control population . persistent damage to hepatocytes reduces the production of a peptide hormone , hepcidin , leading to iron absorption and deposition irrespective of existing iron stores . thus , hepatic iron levels are significantly increased in patients with chronic viral hepatitis b / c . currently , phlebotomy along with a low iron diet is the second - line therapeutic strategy after -interferon administration to prevent hepatocellular carcinoma in japan . several epidemiological studies have suggested an association between endometriosis and ovarian cancer by demonstrating a high risk of ovarian cancer in women with a long - standing history ( > 10 years ) of ovarian endometriosis . here , hemorrhagic retention every month leads to localized iron overload in the ovary . we recently showed that the epithelia of endometriotic cysts are oxidatively stressed and contain high levels of catalytic iron . asbestos fibers have been heavily used for industrial applications since world war ii because of their durability , heat - resistance and low cost . however , in 1987 , iarc designated asbestos fibers as a group i ( definite ) carcinogen for humans ( http://monographs.iarc.fr/eng/classification/crthgr01.php ) . epidemiological studies suggest that asbestos fibers that contain iron ( a transition metal which catalyzes free radical generation ) are more carcinogenic . our research group has been working on iron - induced carcinogenesis for more than 20 years . i came across the ferric nitrilotriacetate ( fe - nta)-induced renal carcinogenesis model when i was a graduate student . shigeru okada , my mentor , serendipitously discovered this model while he was studying the iron loading effects of fe - nta on the liver . chelation of metals alters their biological effects , presumably because metals are not easily dissolved into solution at neutral ph while chelation makes dissolution possible . this is an excellent model that accurately reproduces both acute renal tubular damage and carcinogenesis . multiple studies and subsequent papers have been based on the use of this single model , including the development of monoclonal antibodies against 4-hydroxy-2-nonenal - modified proteins and 8-hydroxy-2'-deoxyguanosine . thus , it is natural to think that every portion of the genome is randomly damaged by this species and to hypothesize that there would be no specific target genes in this carcinogenesis model . we tried to address this question in the 1990 s and unexpectedly found that target genes do exist . at that time , rat genomic information was largely not available , so we had to literally perform thousands of pcr reactions to find common allelic loss in the genome by using microsatellite markers . fortunately , we reached a conclusion that cdkn2a/2b , which encode inhibitors for cyclin - dependent kinases , are major target genes in this model . recently , our results were confirmed with a modern technology called array - based comparative genome hybridization analysis . surprisingly , cdkn2a/2b are target genes in human malignant mesothelioma , a type of cancer which has been strongly associated with asbestos exposure . as many as 74% of cases of human malignant mesothelioma had homozygous deletion of cdkn2a . we observed an even higher frequency of homozygous deletion of cdkn2a/2b in rat peritoneal mesothelioma induced either by chryostile , crocidolite or amosite ( jiang l and toyokuni s , unpublished observation ) . interestingly , iron compounds alone ( ferric saccharate with nitrilotriacetate ) can generate malignant mesothelioma in rats albeit lower incidence and longer incubation period , and we recently found that sarcomatoid types of these mesotheliomas had a high incidence ( 80% ) of homozygous deletion of cdkn2a . based on these three examples of animal experiments , we can hypothesize that excess iron causes deletion of cdkn2a/2b . the genomic sequence at cdkn2a generates another tumor suppressing gene called arf by alternative splicing that works as an inhibitor of tp53 specific ubiquitin ligase . thus , this genomic location acts as a guardian of the genome , and genes corresponding to this location are involved in both the rb and tp53 pathways ( fig . 2 ) . it is also interesting to note that p16 protein ( the product of cdkn2a ) levels decrease with age , and that established cancer cell lines have a high incidence of cdkn2a homozygous deletion . taken together , these findings suggest that oxidative stress , either by excess iron or a high concentration of oxygen , induced this genetic alteration . cdkn2a/2b are really mysterious genomic points , and we are currently using oxygenomics as a strategy to investigate the loci . during this decade , iron metabolism has been further elucidated and many novel molecules and transporters have been identified . among the organelles , the mitochondrion is at the center of iron metabolism , producing iron - sulfur cluster and heme . abnormality of its specific chaperone , frataxin , causes decreased iron storage in mitochondria with concomitant cytoplasmic iron accumulation . this can lead to a neurodegenerative disorder called friedreich ataxia , thus indicating that iron excess damages neurons as well . throughout evolutional and developmental processes , iron has been and will continue to be necessary . however , it is now apparent that iron excess is harmful and even promotes cancer . the current mean lifetime for the japanese was 86.1 years for females and 79.3 years for males in 2009 . this is a great victory of the public health service , considering that the mean lifetime expectancy was approximately 50 years immediately following world war ii . iron modulation by phlebotomy ( blood donation ) , low iron diet or chelation therapy may be a strategy to prevent cancer and possibly other diseases on the condition that the person is healthy and without anemia ( fig . 3 ) . cdkn2a/2b are intriguing genomic crossroads for cancer and aging , which is involved in both the rb and tp53 pathways . this gene is evolutionally conserved between fish ( xyphophorus maculates and fugu rubripes ) and mammals . elucidation of the evolution of this gene would help to clarify further grounds for research into longevity . Output:	persistent oxidative stress has been associated with carcinogenesis . iron overload is considered one such condition that causes oxidative stress . epidemiological studies support a close link between iron overload and carcinogenesis . reportedly , regular semiannual phlebotomies reduced cancer risk in an otherwise normal population . more specifically , genetic hemochromatosis , chronic viral hepatitis , ovarian endometriosis and asbestosis induce iron overload , which can lead to hepatocellular carcinoma , ovarian carcinoma or mesothelioma in humans . through a combination of animal experiments and microarray analyses , homozygous deletion of cdkn2a/2b has been recognized as one of the major target genes involved in iron overload - induced carcinogenesis . cdkn2a/2b are the second most frequently inactivated tumor suppressing genes in human cancers . currently , when infection is becoming sufficiently controlled worldwide , iron regulation may be the next target for human longevity .
PubmedSumm118887	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: psoriasis is a chronic inflammatory skin disease characterized clinically by red scaly patches developing in any part of the body with a relapse - remitting course . systemic arthritis complicates psoriasis in approximately 20% of the patients,1 and its clinical picture resembles that of rheumatoid arthritis with regard to therapeutic efficacy of the monoclonal anti - tumor necrosis factor ( tnf)- antibody , such as infliximab and adalimumab . several recent reports have demonstrated that t - helper 1 cells ( th1 ) , t - helper 17 cells ( th17 ) and regulatory t cells ( treg ) may play a central role in the pathogenesis of psoriatic arthritis ( psa ) via interaction with dendritic cells , leading to accelerated production of tnf.2,3 here , we report a patient with psa associated with chronic renal failure on hemodialysis who was successfully treated with adalimumab alone . flow cytometry showed a persistent decrease in th1 cells after starting adalimumab , and we postulate that this circulating lymphocyte subpopulation may be useful as a therapeutic marker of psa . a 57-year - old man with a 9-year history of hemodialysis for chronic renal failure due to glomerulonephritis became aware of arthralgia in multiple joints with no precipitating cause . he was treated with oral prednisolone at a dose of 5 to 7.5 mg daily in a neighboring hospital , but systemic arthralgia worsened gradually . when he was referred to our hospital , physical examination showed swelling and tenderness in bilateral proximal interphalangeal ( pip ) joints , wrists , knees , ankles and metatarsophalangeal joints with no significant skin lesions . laboratory tests demonstrated an increase in inflammatory reactions , such as c - reactive protein ( crp ) ( 1.28 mg / dl , normal < 0.1 mg / dl ) and renal dysfunction ( creatinine 4.28 mg / dl , normal 0.61.0 mg / dl ; blood urea nitrogen 78.5 mg / dl , normal 820 mg / dl ) but no positive results in autoantibodies , including rheumatoid factor and the anti - cyclic citrullinated peptide and anti - nuclear antibodies . the disease activity score including a 28-joint count ( das28)-crp calculated according to the approved formula ( http://www.das-score.nl/ ) was 3.79 . approximately 10 months later he noticed eruptions on his head , elbows , fingers and knees with hyperkeratosis and discoloration in his nails , which were clinically diagnosed as psoriasis by a dermatologist , in conjunction with worsening of his systemic arthritis and elevations of crp ( 3.31 mg / dl ) ( fig . the psoriasis area and severity index ( pasi ) was relatively low ( 6.0 ) , but das28-crp indicated high disease activity of arthritis ( 6.88 ) . adalimumab was started at 80 mg initially , followed by 40 mg every other week . the patient showed dramatic improvement of his arthritis as well as psoriasis , and das28-crp and pasi decreased to 2.41 and 2.8 , respectively , 2 weeks after starting adalimumab ( fig . 2 ) . on flow cytometry before treatment cd4 interferon- ( th1 ) and cd4 interleukin-17 ( th17 ) cells in peripheral blood were higher than those of age - matched healthy controls , but cd4cd25foxp-3 cells ( treg ) showed no obvious increase . all of these lymphocyte subpopulations were decreased eight weeks after starting adalimumab compared with before ( fig . cd4 interleukin-4 cells ( t - helper 2 ) showed no significant change before and after treatment . twelve weeks after starting adalimumab , cd4 interleukin-17 and cd4cd25foxp-3 cells returned to the pretreatment level but cd4 interferon- cells remained at low levels . he has since been in good general health with no arthralgia or adverse events under regular administration of adalimumab . the present patient was diagnosed as having psa based on polyarthritis with skin and nail lesions characteristic of psoriasis . in approximately 19% of psa polyarthritis has been reported to precede psoriasis , as seen in the present patient.4 methotrexate and cyclosporine a are usually potent therapeutic options for psa , but these drugs were inadequate in the present patient because of chronic renal failure requiring hemodialysis.5 biologics are the next choice . several recent reports have demonstrated that early use of biologics can ameliorate polyarthralgia and skin lesions in rheumatic disorders , including psa , associated with chronic renal failure on hemodialysis ( table 1).512 biologics targeting tnf are most frequently used in this situation , and among them etanercept has been reported to show pharmacokinetics similar to those in healthy subjects even under chronic renal failure on hemodialysis.13 however , the use of etanercept is not allowed in psa in japan . in the present patient , therefore , we decided to employ adalimumab , which is a human anti - tnf- monoclonal antibody usable in psa without coadministrations of methotrexate . the usual dose of adalimumab is 40 mg , but 80 mg was selected as an initial dose in the present patient because of severe systemic arthritis.14 soon after starting this drug both polyathritis and psoriasis improved in parallel with a decrease in inflammatory reactions . the patient has so far shown no serious adverse events ascribable to adalimumab . in the present patient we serially analyzed phenotypes of peripheral blood lymphocytes using flow cytometry . th1 and th17 cells showed significantly higher levels before treatment compared with those of age - matched healthy controls as described in the previous report from another institute,2 but treg cells did not . th17 and treg cells returned to the pretreatment level 12 weeks after starting adalimumab , while th1 cells remained at low levels in conjunction with the suppressed activity of psa . the decreases in th1 , th17 and treg cells after treatment are ascribable to 3 possible mechanisms . this drug can react with tnf- in peripheral blood but also with that expressed on immune competent cells , including t lymphocytes.15 the interaction between tnf- on the cell surface and adalimumab may have produced cytotoxicity , resulting in a rapid elimination of th1 , th17 and treg cells . the second possible mechanism is anti - tnf - mediated induction or recovery of cell populations capable of regulating th1 and th17 cells.16 treg cells are suitable candidates , but in the present patient this subpopulation was simultaneously decreased 8 weeks after starting adalimumab . the third possible mechanism is inhibition of circulating tnf- , which has multipotentials on immune systems . as tnf- can promote differentiation and maturation of t cells,2,16 adalimumab - induced reduction of this cytokine in peripheral blood may have caused alterations of t - lymphocyte subpopulations as seen in the present patient . the reincreases in th17 and treg cells 12 weeks after starting treatment are probably due to rapid differentiation or mobilization into peripheral blood via some other stimulating mediators , such as interleukin-2 and transforming growth factor-1719 although the precise mechanisms are unclear . chronic renal failure itself also has a positive effect on th17 cells irrespective of maintenance hemodialysis.20 considering that th1 cells were the only lymphocytes showing obvious change persistently after starting adalimumab in the present patient , this subpopulation may be able to more sensitively reflect disease activity of psa than th17 and treg . in conclusion , adalimumab monotherapy is a potent therapeutic option in patients with psa with regard to clinical efficacy and safety even under hemodialysis for associated chronic renal failure . further studies in a set of patients are necessary in order to clarify whether or not th1 cells are a useful clinical marker indicating disease activity of psa . Output:	we report a patient with psoriatic arthritis ( psa ) who was successfully treated with adalimumab even while under hemodialysis therapy for associated chronic renal failure . flow cytometry of circulating lymphocytes revealed an obvious decrease in both th1 and th17 cells after starting adalimumab . the latter returned to the pretreatment level in the course of adalimumab therapy , while the former did not . adalimumab is a potent therapeutic option for psa patients with chronic renal failure on hemodialysis , and th1 in peripheral blood may reflect the disease activity .
PubmedSumm118888	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: although the incidence of bacterial pneumonia has steadily decreased according to the improved public hygiene in the developed countries , streptococcus pneumoniae is still one of the most common pathogens of childhood empyema ( 1 ) . transient hypogammaglobulinemia of infancy ( thi ) is originally defined as a physiological maturation defect of immunoglobulin g ( igg ) production that occurs at 3 - 6 months of age and it lasts until 18 to 36 months of age . the majority of children with thi may be asymptomatic , but children with recurrent infections have been incidentally detected as having thi ( 2 - 5 ) . we report here on a 22-month - old child with thi and iga deficiency and she had massive pneumococcal empyema . after this episode , she has not experienced recurrent infections or a severe infectious episode , and she has shown a normal growth pattern . her igg level returned to normal within 6 months , but iga level is still low at 6 yr of age . a 22-month - old girl was admitted to our hospital because of dyspnea and peripheral cyanosis for 2 days . she had no known history of severe infections and no familial history of immunodeficiency . before admission , she had complained of cough with sputum for 2 weeks and she had visited private clinics 3 times . fever was noticed for 2 days at the first visit to the clinic , since then she had remained afebrile . the weight , height and head circumference of the patient were within the normal percentile ranges for her age . laboratory investigations revealed hemoglobin 14.9 g / dl , white blood cell count 14,000/l ( 66% neutrophils and 30% lymphocytes ) , platelet count 123,000/l , erythrocyte sedimentation rate at 1 hr 2 mm / hr and c - reactive protein 0.1 mg / dl . the blood chemistry analysis was non - specific except elevated alkaline phosphatase 685 iu / l ( 96 - 254 iu / l ) and lactate dehydrogenase ( ldh ) 823 iu / l ( 145 - 420 the serum complement levels were c3 61.4 mg / dl ( 77 - 195 mg / dl ) , and c4 10.0 g / dl ( 7 - 40 mg / dl ) . a chest computed tomography ( ct ) performed on admission day showed massive pleural effusion with a totally collapsed left lung , and the heart was shifted to the right side ( fig . the values of immunoglobulins on the 14th admission day were igg 336 mg / dl ( reference level for age : 345 - 1,236 mg / dl ) , iga < 13 mg / dl ( 14 - 159 mg / dl ) , igm 87.6 mg / dl ( 43 - 207 mg / dl ) and ige 31 iu / ml ( 0 - 170 iu / ml ) . although all the values of igg subclasses were low , there was no igg subclass that was not detected . isohemagglutinin and the antibodies from vaccination ( anti - diphtheria igg , anti - tetanus igg and anti - polio virus iggs ) were all detected . the lymphocyte subset tests showed that the pan - t cells were 51.6% ( 28 - 77% ) , the cd4 + cells 25.3% ( 32 - 68% ) , the cd8 + cells 23.6% ( 10 - 36% ) and the b cells 36.5% ( 10 - 20% ) . the degree of t cell proliferation to mitogens ( phytohemagglutinin and anti - cd3/anti - cd 28 monoclonal antibodies ) was comparable to that of the age - matched control . on the second day of hospitalization , a chest tube was inserted to the pleural cavity and ~300 ml of milky colored fluid was evacuated . the pleural fluid analysis revealed an exudate with subsequent heavy growth of s. pneumoniae ; the organism was resistant to penicillin , but sensitive to ceftriaxone . the clinical course of the patient treated with the chest tube drainage and an antibiotic regimen ( ceftriaxone ) was uneventful and there was no residual lesion on the chest radiograph taken 6 months later . the patient did not receive intravenous immunoglobulin therapy during hospitalization or subsequent supplementary therapy for hypogammaglobulinemia . after 1 yr , the low levels of igg and c3 and the ratio of cd4 + t cells were recovered to within the normal range for her age , but her iga level did not recover ( table 1 ) . the immune system of early childhood is not fully matured compared to adults , and some immune functions may mature during childhood . the phenotype of some infectious diseases such as hepatitis a is age - dependent , and most children under 5 yr of age are largely asymptomatic or innocuous without jaundice when they are affected by hepatitis a virus ( 6 ) . kawasaki disease is an acute febrile systemic vasculitis of an unknown etiology , but it may be an immunemediated disease that manifests after an infection by unknown pathogens ( 7 ) . this disease has a strict age predilection between 6 months and 4 yr of age . in addition , other early childhood immune - mediated disorders that have a strict age restrictions with a self - limited clinical nature are known ; transient erythroblastopenia of childhood ( tec ) ( 8) , autoimmune neutropenia of infancy ( ani ) ( 9 ) , and childhood immune thrombocytopenic purpura ( itp ) ( 10 ) . all these findings indicate that the maturing immune system in early childhood ( < 5 yr of age ) may be involved in the phenotype of infectious and immune - mediated disorders . thi also occurs mainly at 3 - 6 months of age and it lasts until 18 to 36 months of age with self - limiting recovery . thus , it may be regarded as one of the disease category that reflects immunologic immaturity during early childhood . the pathogenesis of thi remains unknown , although delayed functional maturation of b cells , a numerical reduction of helper t cells ( also suggested in our case ) , and cytokine imbalance have been postulated ( 2 - 5 , 11 , 12 ) . most of the children with tec , ani or itp are proposed to experience a variety of infections , and especially those of a viral origin before presentation of illness . it is postulated that thi may also be associated with an infection and the subsequent immune perturbation is responsible for the pathogenesis of thi . neutrophils and other phagocytes are the first defense line against extracellular bacterial pathogens , and humoral immunity ( antibodies ) has a crucial role for phagocytosis against encapsulated bacteria such as s. pneumoniae and h. influenzae . thus , the patients with humoral immunodeficiencies such as x - linked agammaglobulinemia ( xla ) and common variable immunodeficiency ( cvid ) mainly complain of recurrent infections from such bacteria ( 13 ) . a majority of children with thi are detected by clinical manifestations like recurrent upper respiratory infections , but they have few severe infections during the follow - up period ( 2 - 5 ) . some children with thi experience severe or life - threatening infections such as sepsis or severe pneumonia , like happened in our case ( 14 - 16 ) . since the patients with thi are believed to have a normal capacity to produce specific antibodies , in contrast to xla and cvid patients , the low level of igg alone may not be responsible for a severe infection with encapsulated bacteria . our patient was also noted to have an intact humoral immunity and a normal t cell proliferation response with a decreased cd4 + t cell count . the low levels of igg , c3 and cd4 + t cells were recovered within 6 - 12 months . thus , other transient immune disturbances concerned with phagocytosis or other immune function may manifest severe infections in some of the patients with thi , including our case , although we did not perform extended immunologic studies at presentation . previous studies have indicated that a subgroup of thi patients had a persistent low value of igg beyond > 4 yr of age and this was commonly associated with low iga values ( iga immunodeficiency ) or dysgammagrobulinemia ( 2 - 5 , 14 ) . these findings suggest that thi may consist of a heterogenous group of immunodeficiencies and thi may have the possibility of an early manifestation of a primary immunodeficiency such as cvid , although there are few reports on the association between thi and primary immunodeficiency . although thi is an age - dependent and self - limiting disorder , severe infections may occur , including atypical presentation of infections that need immunologic study . long - term follow - up of the clinical condition of these patients and their immunologic status are necessary to rule out primary immunodeficiency disorders . Output:	transient hypogammaglobulinemia of infancy ( thi ) is originally defined as a physiological maturation defect of immunoglobulin g ( igg ) production that occurs at 3 - 6 months of age and lasts until 18 to 36 months of age . we report here on a 22-month - old child with thi and iga deficiency , who had massive pneumococcal empyema . her depressed igg level returned to normal within 6 months , but iga level was still low at 6 yr of age . although thi is an age - dependent and self - limiting disorder , severe infection that includes an atypical presentation of an infection may occur in some patients and this requires evaluation with immunologic study .
PubmedSumm118889	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: major adverse effects include peripheral neuropathy , myelotoxicity , bradycardia , hypotension , arthralgia , myalgia , granulocytopenia and hypersensitivity [ 2 , 3 ] . to date , several cases of patients developing paclitaxel - induced interstitial pneumonitis have been reported , with estimated frequencies of 0.7312% . trastuzumab - induced pneumonitis may present as rapidly progressive pulmonary infiltrate respiratory failure after the administration of 1 dose of trastuzumab or after 6 weeks of therapy . although there is one report of fatal pneumonitis associated with docetaxel ( taxotere)/trastuzumab therapy , no fatalities associated with paclitaxel / trastuzumab combination therapy have been reported to date . a 51-year - old female patient , nonsmoker and with no comorbid disease , was diagnosed with locally advanced left breast cancer ( t2n1m0 ) . neoadjuvant treatment comprised paclitaxel 80 mg / m weekly for 12 weeks concurrent with trastuzumab 4 mg / m loading dose in week 1 , then 2 mg / m weekly for 11 weeks . as per protocol , the patient was given dexamethasone prior to chemotherapy . when she was due for week 10 of the therapy , she complained of shortness of breath , dry cough and fever . her clinical examination revealed the following : temperature 39.6c , heart rate 104 bpm , bp 96/33 mm hg , respiratory rate 30 cycles / min and spo2 84% on room air . the patient was admitted to hospital and started on therapy with 4 liters o2 per nasal canula , and tazocin ( piperacillin sodium- tazobactam sodium ) 4.5 g every 8 h and vancomycin 1 g every 12 h empirically after drawing blood for culture and sensitivity . at this time , the patient was not neutropenic and the following laboratory values were noted : wbc 5.5 10/l , anc 4.3 10/l , hb 91 her renal and liver functions were within normal range , echocardiography was normal , both blood and sputum cultures were negative for acid - fast bacteria and fungal infection , and urine culture showed no growth . x - ray showed ground - glass opacification of the lungs ( fig . 1 ) and spiral chest ct showed satisfactory opacification of the pulmonary trunk , and right and left main pulmonary arteries , with no evidence of central pulmonary embolism . bilateral airspace disease consistent with pulmonary edema was noted , along with no detectable lung nodules , and no evidence of either pleural or pericardial effusion ( fig . special stains for afb , fungus , pneumonitis jirovecii ( carinii ) pneumonia and cmv immunohistochemistry were all negative . bronchoscopic lung biopsy showed moderate interstitial inflammatory infiltrate composed of polymorphonuclear leukocytes , lymphocytes and some histiocytes forming occasional aggregates . the alveolar spaces showed focal deposits of fibrin ; there was focal pneumocyte atypia and hyperplasia , as well as focal intra - alveolar hemorrhage . bronchoalveolar lavage was negative for malignant cells and viral inclusion bodies ; however , reactive lymphocytes were present . scattered pulmonary macrophages were noted against a background of reactive lymphocytes , and only occasional eosinophils were seen . based on the above - mentioned findings , a diagnosis of acute interstitial pneumonitis was made . although the patient 's fever had subsided and her blood pressure had begun to normalize , lung auscultation revealed the same initial crepitations and the patient was still in need of o2 supply ( 4 l / h ) . a pulmonary function test ( spirometry ) yielded the following prebronchodilator results : fev1 49.9% and fvc 43.5% ; the postbronchodilator differences were 16% for fev1 and 27.6% for fvc . due to a very short exhalation time of 12 s max . , the patient was unable to exhale maximally in order to record total lung capacity furthermore , the patient refused to complete the postbronchodilator spirometry test due to shortness of breath . given the data at hand , the best possible flow volume loop was chosen . as there was no indication of any type of infection , the case was diagnosed as drug - induced interstitial pneumonitis , antibiotics were withdrawn and treatment with prednisone 40 mg orally once daily was begun within 18 h of initial presentation . the patient 's crepitations disappeared and her oxygen saturation reached 95% on room air . a chest x - ray taken 18 h after initiation of prednisone ( fig . 3a ) showed improvement in the lung picture compared to the initial radiograph . a follow - up x - ray taken 48 h after initiation of prednisone ( fig . 3b ) was completely normal , so the patient was discharged home in very good general condition without the need for o2 supply . follow - up continued in the outpatient clinic , including the completion of a 10-day course of prednisone . drug - induced infiltrative lung disease ( di - ild ) is the most common form of anti - neoplastic agent - induced respiratory disease . patterns of di - ild are non - specific interstitial pneumonia , eosinophilic pneumonia , hypersensitivity pneumonitis , pulmonary fibrosis , or organizing pneumonia . early withdrawal of the causative drug will often lead to improvement or even cure of the ild . in several series , trastuzumab has been well tolerated , and its addition to chemotherapy does not significantly increase the frequency of side effects . infusion - related events are common but rarely severe , and more common during the first administration of the drug . in an analysis of the safety of trastuzumab administered to 25,000 patients , the only respiratory - associated serious adverse event was bronchospasm . however , apart from the previously described infusion - related bronchospasms , rare cases of interstitial pneumonitis have been reported . one patient with organizing pneumonia and another with pneumonitis were reported ; both events were probably due to trastuzumab administration [ 11 , 12 ] . in trial b-31 , four patients in the trastuzumab group had interstitial pneumonitis , one of whom died . in the n9831 trial , five patients in the trastuzumab group had grade 3 + pneumonitis or pulmonary infiltrates , one of whom died . paclitaxel acts against tumors through both promotion of microtubule assembly and inhibition of microtubule disassembly , activities that result in disruption of cell division and cell death . hypersensitivity reactions are well - recognized complications of paclitaxel therapy and typically occur with the first or second dose . these reactions are characterized by dyspnea , hypotension , bronchospasm , urticaria , and erythematous rashes . severity of these symptoms ranges from mild dyspnea to respiratory failure requiring mechanical ventilation [ 15 , 16 ] . it may be mediated by the release of histamines or other vasoactive substances similar to anaphylactoid reactions encountered with iv contrast agents , or it may result from a delayed hypersensitivity response . kuip and muller reported a case in which a patient presented with fever and dyspnea after a second dose of docetaxel / trastuzumab . the patient died due to respiratory failure 3 weeks later and interstitial pneumonitis was diagnosed at autopsy . in spite of accompanying dexamethasone and antihistamines given concurrently with paclitaxel / trastuzumab , our patient , like that of kuip and muller , developed interstitial pneumonitis with concomitant complaint of dry cough , fever and dyspnea after 9 weeks of therapy . our patient 's symptoms appeared later than what has been reported in the literature for each medication separately . fortunately , the diagnosis of interstitial pneumonitis was expected and confirmed and our patient recovered completely . since they have synergistic efficacy against the tumor , could they be synergistic in the side effects as well ? as the two drugs were given concurrently and the patient had no known risk factors to anticipate this reaction , and there is no clear diagnostic test to confirm which drug caused the pneumonitis , it is difficult to be sure of the offensive drug . it is well known that trastuzumab infusion - related events are common but rarely severe , and that they are more common during the first administration , usually within 2.5 h. trastuzumab - associated pneumonitis may develop many months after initiation of treatment and may run a more insidious course . in view of the extensive use of trastuzumab nowadays , trastuzumab - induced pneumonitis , if existent , seems rarer than paclitaxel - induced pneumonitis . this leads us to conclude that the pneumonitis in our patient was most likely due to paclitaxel . although pneumonitis is a rare side effect of paclitaxel / trastuzumab administration , it is important to be aware of this specific toxicity . importantly , Output:	pneumonitis is a rare but serious complication associated with paclitaxel and/or trastuzumab treatment . we report a 51-year - old female patient with locally advanced breast cancer who presented with shortness of breath , fever , dry cough and pulmonary infiltrates . she had been treated without complications for 10 weeks with paclitaxel ( taxol ) and trastuzumab ( herceptin ) as neoadjuvant therapy , with complete clinical and pathological response . infections and cardiomyopathy were excluded as causes of her symptoms . bronchoscopy and biopsy were performed and a diagnosis of drug - induced interstitial pneumonitis was made . after treatment with steroids , the patient showed a significant response in less than 24 h ; she was discharged home without the need for oxygen less than 48 h after therapy initiation . although no causative association could be found between either trastuzumab or paclitaxel and this patient 's pulmonary syndrome , the potential for such toxicity should be considered , especially as paclitaxel / trastuzumab is a vey common combination therapy for breast cancer .
PubmedSumm118890	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: abdominal pregnancy is a rare form of ectopic pregnancy with high morbidity and mortality for both the mother and the fetus . ectopic pregnancy represents about 12% of all pregnancies , with 95% of those occurring in the fallopian tubes . the incidence of abdominal pregnancy varies in different populations , ranging from 1:10 000 to 1:30 000 pregnancies , and being most prevalent in developing countries with limited resources and limited diagnostic facilities . the diagnosis of abdominal pregnancy can be challenging , especially in a resource - limited setting . when discovered early , laparotomy is usually done due to the high risk it carries to the mother . an abdominal pregnancy that reaches term with a healthy mother and fetus , thus , is a rare occasion . a 25-year - old g2p0 , presented to the maternity department in msf agok hospital in south sudan , on 14th of october 2016 with abdominal pain . her pregnancy was estimated to be 3435 weeks , as she did not know the exact date of her last menstrual cycle . she had a previous miscarriage , and was concerned about this pregnancy . on examination , the abdomen was mildly tender , and the fetal head could be easily palpated at the right upper quadrant . ultrasound scan was performed , which confirmed a live term fetus , in transverse lie , with no indication of extra - uterine pregnancy . caesarean section was planned in view of the transverse lie . a pfannenstiel ( transverse lower abdominal ) incision was used . a normal non - pregnant uterus there was active bleeding from the placenta , which was attached to the fundus and left cornual region of the uterus , the small bowel mesentery and the left lateral abdominal wall . left ovary was found to be normal , but the left fallopian tube could not be discerned . the baby was well , weighing 2.5 kg , and showing no obvious external congenital abnormalities . both the mother and the baby were kept in the hospital for 2 weeks postoperatively , during which the mother recovered well from surgery , with no signs of infection or bleeding . the child has shown normal developmental milestones till date ( 6 weeks after birth ) . primary abdominal pregnancy refers to an extra - uterine pregnancy where implantation of a fertilized ovum occurs directly in the abdominal cavity while the secondary abdominal pregnancy is a tubal pregnancy that ruptures with reimplantation within the abdominal cavity usually resulting in tubal or ovarian damage . our patient most likely had a secondary abdominal pregnancy , as the left sided fallopian tube could not be identified intraoperatively . a patient usually presents with signs of intra - abdominal bleeding due to separation of the placenta . abdominal pain , painful fetal movements , abnormal presentation and uneffaced cervix should arouse suspicion of ectopic pregnancy , especially abdominal pregnancy . ultrasonography findings of intra - abdominal , extra - uterine fetus and placenta confirms the diagnosis . but even with routine ultrasonography examination , the diagnosis can be missed , especially in the later stages of pregnancy . in a limited - resource setting , such as a field hospital in south sudan optimal management requires careful evaluation and planning . generally speaking , for previable abdominal pregnancies , i.e. prior to 24 week of gestation , immediate operative intervention is indicated , but for viable pregnancies presenting after 24 weeks of gestation , a more conservative approach is advocated , provided the patient can be under strict observation , preferably in a hospital . bleeding from the placental implantation site is the most serious and life - threatening complication of abdominal pregnancy . usually complete removal of the placenta is not advised , and partial removal is only advised to control bleeding . otherwise , it should be left in situ and is removed by involution and resorption . this is usually monitored by measuring the serum human chorionic gonadotropin levels on follow up . in this case , clinical examination and monitoring of the haemoglobin level were the only means available for monitoring the patient . for the newborn , congenital malformations are common , with reports of fetal malformations as high as 40% , with only 50% of these babies surviving the first week of life . Output:	abstractabdominal pregnancy is a rare form of ectopic pregnancy with high morbidity and mortality for both the mother and the fetus . diagnosis can be challenging , especially in a resource - limited setting . we report a case of abdominal pregnancy that presented to mdecins sans frontires field hospital in agok , south sudan , with abdominal pain . examination revealed a term pregnancy and a live fetus in transverse lie . the diagnosis of abdominal pregnancy was made intraoperatively , with successful management and delivery of a healthy baby .
PubmedSumm118891	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: s - adenosyl - l - methionine ( sam ) was discovered approximately 60 years ago . since then , sam has been identified with a wide spectrum of biological processes ranging from the synthesis of various neurotransmitters in the brain and catecholamine metabolism to gene expression and cell growth , differentiation , and apoptosis , to establish the sam empire called by cantoni [ 13 ] . especially as a biological methyl group donor , sam is used as a nutritional supplement and as a prescription drug for various diseases , including liver disease , osteoarthritis , neurologic syndrome , and depression . because sam could only be ingested from the diet but could not be synthesized endogenously in the human body , the demands for sam in synthetic medication and the nutritional supplements have received wild attention all over the world . therefore , an effective method for detecting sam is beneficial to the investigation of the major role of sam in cell function metabolism and the treatment of clinical disorders . also the method can be used to optimize the fermentation conditions in fermentation process by monitoring the production of sam . recently , sturgess measured sam content of the commercially available supplements by high - pressure liquid chromatography - uv diode array detection and showed that the percentage of measured sam was greater than threefold variation compared to the stated amount on the packaging . used high - pressure liquid chromatography ( hplc ) to measure the production of sam and l - isoleucine with 0.67 hayakawa et al . reported that the regulation mechanisms are responsible for sam production by c - metabolic flux analysis . notice that hplc , as the major approach for accurate detection of sam , is rather complex and takes time , implying that it is not suitable for real - time analysis in industry . this stimulates us to seek a novel method which can detect sam concentration easily and quickly as well as cheaply . raman spectroscopy belonging to the molecular vibration spectrum permits the identification of numerous analytes with high discrimination because of its narrow spectral band response . however , the normal raman signal is extremely weak because of its very small raman scattering cross - section which limits seriously its applications in fast and sensitive detection . the raman signals could be efficiently enhanced by surface - enhanced raman scattering ( sers ) technique when molecules were on or near the surface of certain noble metal structures with nanoscale features [ 1214 ] . silver nanoparticles had drawn particular attention for its potential as sers substrate due to their highest electrical and thermal conductivities and strong surface plasmon resonance , which make them attractive for use in biochemistry . the enhancement factors ( efs ) of sers can be as much as 10~10 [ 15 , 16 ] . nowadays , sers , which could minimize photobleaching , peak overlapping , and background signal in complex biological systems , was widely used as a signal - transduction mechanism in biological and chemical sensing . additionally , biological processes containing abundant materials need a more efficient and sensitive detection method . so the sers technique was applied to the detection of sam . in this work , a three - dimensional and highly sensitive sers - active substrate of highly ordered si nanowire array ( si nwa ) decorated by ag nps was prepared first , and the sers spectra of sam were investigated at various concentrations with the ag / si substrate ( ag / si nwa ) . the limit of detections ( lod ) of sam was found experimentally to be as low as 0.1 g / l . furthermore , according to the sers signals of sam with a concentration of 0.1~30 g / l , the linear relationship between the concentration of sam and integrated intensity of peak centered at ~2920 cm ( s2920 ) was established , enabling the qualitative detection of sam . as the practical application , the fast detection of sam concentration can be considered as of two steps : s2920 was first measured in real solutions and then the sam concentration was calculated based on the measured s2920 and the linear relationship . meanwhile , the sam concentrations could also be measured more accurately by hplc for the verification of the calculation result . the relative deviations ( ) of the sam concentration are defined as the ratio of the absolute value of the difference between sam concentration with the fast detection method and that with hplc method . sam and the real solutions were obtained from the school of life sciences of beijing university of chemical technology ( sls , buct ) . n - type ( 100 ) si wafers ( 1~10 cm ) purchased from the tianjin semiconductor technology research institute were used as the substrate material . acetone , alcohol , hf ( 40% ) , h2o2 ( 30% ) , silver nitrate , and deionized water were purchased from the beijing chemical works . all chemical reagents were used as received without further purification . before deposition of ag , si wafer was first cut into dimensions of 1 3 cm and was then ultrasonically cleaned with acetone , ethanol , and distilled water for 5 min , respectively . next the clean si wafer was dried in air . the wafer was placed in a mixture of 4.6 m hf and 0.005 m agno3 for 1 min and then washed with deionized water several times to remove excess ag particles . ag nanoparticles ( nps ) were then deposited on the surface of the si wafer by placing the wafer in a mixture 4.6 m hf and 0.5 m h2o2 at room temperature for 60 min . after that the si wafer was taken out steadily . finally , it was kept in 1 m agno3 solution for 1 min and dried in air . the concentration of sam of real fermentation system is from 1 g / l to 14 the solutions of sam were prepared with concentration ranges of 0.01~30 g / l by diluting the stock solution of sam ( 30 the concentration range is enough to meet the demand for the detection of sam in real fermentation process . the cells were disrupted by sonication for 10 min on ice and then separated by centrifugation at 1000 rpm for 10 min at 0c from the fermentation liquids . sers measurements were performed at room temperature on a labram aramis raman system with the 632.8 nm laser as excitation . the diameter of the light spot area was ~1 m and the incident power was 9 mw . the spectral resolution was 1 cm and the spectra were recorded with an accumulation time of 15 s. the sers substrates were preimmersed in corresponding solution for 30 min to ensure adsorption equilibrium , then rinsed with deionized water , and dried in a vacuum chamber for 5 min at 25c before each sers measurement . the range of sers detection through the whole process was from 550 to 3100 cm at the same condition . the raman band of a si wafer at 520.7 cm was used to calibrate the spectrometer . the background with no chemical information caused by the fluorescence effect in obtained raman spectrum should be removed . the rolling - circle filter ( rcf ) there are two main advantages of the rcf : ( 1 ) it has a single parameter ( radius ) and ( 2 ) there is no restriction on the background shape . this method is based on the geometrical difference between characteristic peaks and background [ 1921 ] . the algorithm and a code written in matlab language we select highly ordered porous si nwa as a template to fabricate ag - based nanostructured sers - active substrates where large - quantity ag nps with appropriate and uniform size were assembled on the surface of si nwa via the reaction between ag ions and si - h bonds . compared with sers substrates based on ag nanoparticle films on monocrystalline si substrate , the porous si nwas have much wider specific areas , allowing an increased loading of ag nps and adsorption of target molecules , as well as the higher possibility of forming hot spots . the typical morphologies of si nwa and ag / si nwa were shown in figure 1 . from the top ( figure 1(a ) ) and cross - sectional ( figure 1(c ) ) views of si nwa , si nws are distributed uniformly on the whole wafers and are oriented perpendicularly to the substrate surface with good uniformity . the diameters of si nws are in the range of 300~1000 nm , while the length is around 10 m . from the amplified fe - sem image of the top view of si nwa , as shown in the inset of figure 1(a ) , it can be observed that the upper ends of si nws bend towards each other to form small bunches . the porous nanostructures of si nws provide a much larger surface area , which is of great significance to load ag nps and to enhance light trapping . after the si nwa is decorated , the representative top ( figure 1(b ) ) and cross - sectional ( figure 1(d ) ) fe - sem images of ag / si nwa , which also intuitively show that substantive ag nps are attached to the surface of each si nw , and a complex and unique nanocomposite array were formed . the raman enhancement effect of the ag / si nwa substrate is studied , and an ef as large as 3.33 10 is calculated , as shown in supplementary figure s1 . the high ef value indicates ag / si nwa has a much better raman enhancement effect than si nwa , which is favorable to ultrasensitive detection . figure 2 shows the original spectrum ( black curve ) and the optimized spectrum ( red curve ) at 10 it could be found that the fluorescence background with no chemical information was removed by rcf processing . the prominent raman peaks of sam at about 677 , 729 , 1041 , 1324 , 1405 , 1510 , and 2920 cm were assigned to ( cs ) , s ( cn ) , ( ch2 ) , ( cc ) , as ( cn ) , and ( ch3 ) , respectively [ 22 , 23 ] . the radius of rcf , as a key parameter , was analyzed to achieve the optimal results . supplementary figure s2(a ) shows the original spectra and the results after applying the rcf with various radii ( 50 , 200 , 400 , 650 , 800 , 1000 , 1200 , and 1600 cm ) . supplementary figure s2(b ) shows how the difference value between the spectra optimized by the rcf and that with the background subtracted manually varies with the radius of rcf . from supplementary figure s2(b ) , it could be concluded that the optimal radius r is around 650 cm . when r > 650 cm , the background is partly subtracted , and when r < 650 cm , the raman spectra may have distortion . therefore , it is verified that r of rcf is significantly greater than the raman line width and less than the radius of curvature of the background in the spectrum . usually , the statistical approaches such as partial least square regression ( plsr ) , support vector machine ( svm ) , and gaussian mixture discriminant analysis are combined with principal components analysis ( pca ) to quantitatively analyze mixture by raman or sers . in the sam fermentation solution , there is a mass of materials , including the water , inorganic salt , alcohol , ketone with no obvious raman signals , and sam with sharp characteristic peaks . with single analyte , we introduce the linear analysis with the relationship between raman intensity and the concentration of sam . figures 3(a ) and 3(b ) show , respectively , the detection of 0.01 to 30 g / l sam and the establishment of linear relationship between sam concentration and s2920 . as shown in figure 3(a ) , the sers spectra exhibit good regularity , and the intensity recedes with the decrease of sam concentration . based on the data presented in figure 3(a ) , the relationship curve between the s2920 ( average and standard deviation from 8 samples ) and the concentration was established . clearly , the dependence of s2920 on the sam concentration is nearly linear over the concentration range which was depicted in figure 3(b ) . this linear relationship ( y = 240.10x + 112.65 ) between s2920 and sam concentration allows for the calibration of our substrate to determine unknown concentration of sam in solutions . as shown in supplementary figure s3 , there is no obvious raman spectrum when the sam concentration decreases to 0.01 g / l whether on ag / si nwa or si nwa substrate , and sers signals can be merely detected at the concentration of 0.1 g / l , and the linear relationship established above is applicable in the range from 0.1 g / l to 30 g / l , allowing for the quantitative determination of sam . in order to investigate whether the concentration of sam could be assessed by sers technology in real biological samples , we try to study the application of raman spectrum in real solutions containing sam at different concentration . the corresponding raman spectra could be seen in figure 4 . as shown in figure 4(a ) , the spectra showed obviously that raman peaks were centered at 970 cm and 2920 cm . the sers intensity of the mineral salts and glucose contained in real solutions was so weak that it could not be obviously observed . the raman peaks centered at 970 cm and 2920 cm were assigned to si nwa and the ch3 symmetric stretching of sam , respectively . the area of peak centered at 2920 cm showed an increasing trend with concentration of sam which verified that the raman peak at 2920 cm was aroused by sam . based on the linear relationship in figure 4(b ) , the sam concentration could be calculated and the results were listed in table 1 . hplc analysis of real solutions had also been applied to verify the linear function relation and the corresponding results were also listed in table 1 . the measured value and error of the real solutions were presented , which validates the consistency and the accuracy of the linear relationship . comparing these data , less than 13% ( including two bigger relative deviations with 12.6% and 11.13% and others less than 5% ) the predicted concentrations of sam as a function of the value obtained by hplc were plotted and shown in figure 3(b ) . therefore , the determination data were well consistent with the calculated data , indicating that a new method of quantitative determination of concentration of sam has been developed based on the ag / si nwa sers substrate . a new method , surface - enhanced raman scattering , to detect the sam concentration rapidly and conveniently was proposed by us . in the investigation carried out here , the linear relationship ( y = 240.10x + 112.65 ) between the concentration of sam and the integrated intensity of peak centered at ~2920 cm was established . experimentally the lod of sam is 0.1 g / l . as the concentration of sam the linear relationship has the same dependence of sam concentration in aqueous solutions and the real solutions , due to the weak influence on 2920 cm of other contents in biological cells . this investigation provided a possibility for carrying out rapid detection on sam . with the mathematic approaches used to establish the predictable relationship including rcf and linear analysis , this research provided a reference to study the relationship between the concentration of sam and the sers signals . furthermore , the results obtained may be applied to the detection for synthesis of sam and the sam contention in biological process . Output:	concentrations of s - adenosyl - l - methionine ( sam ) in aqueous solution and fermentation liquids were quantitatively determined by surface - enhanced raman scattering ( sers ) and verified by high - pressure liquid chromatography ( hplc ) . the ag nanoparticle / silicon nanowire array substrate was fabricated and employed as an active sers substrate to indirectly measure the sam concentration . the linear relationship between the integrated intensity of peak centered at ~2920 cm1 in sers spectra and the sam concentration was established , and the limit of detections of sam concentrations was analyzed to be ~0.1 g / l . the concentration of sam in real solution could be predicted by the linear relationship and verified by the hplc detection method . the relative deviations ( ) of the predicted sam concentration are less than 13% and the correlation coefficient is 0.9998 . rolling - circle filter was utilized to subtract fluorescence background and the optimal results were obtained when the radius of the analyzing circle is 650 cm1 .
PubmedSumm118892	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: the study design and procedures were approved by the study site 's institutional review board . the study was conducted at kaiser permanente northwest ( kpnw ) , a not - for - profit hmo in the pacific northwest with 480,000 members . electronic medical records include patient weight , blood pressure , height , smoking status , diagnoses , treatment procedures , medications , and laboratory results . the kpnw diabetes registry has been shown to be 99.5% specific and 99% sensitive for diabetes diagnosis compared with chart review ( 9 ) . kpnw members with diabetes are demographically and clinically similar to the national population of patients with diabetes ( 9 ) . the study site 's clinical guidelines for diabetes care are consistent with prevailing guidelines ( 10 ) . guidelines recommend lifestyle management for all people with diabetes and a stepped - care approach to medication use for control of risk factors . most newly diagnosed members attend diabetes classes , and hmo weight - related health - education classes are available for a fee . this retrospective cohort study evaluated 3-year weight trajectory patterns in subjects aged 2175 years and newly diagnosed with type 2 diabetes , as well as the patterns effects on a1c and blood pressure in year 4 . we identified all men and women aged 2175 years with any evidence of type 2 diabetes ( n = 38,430 ) . we then limited the population to those with newly diagnosed type 2 diabetes from 1 january 1997 to 31 december 2002 ( n = 17,403 ) and then further limited it to those with 12 months pre- and 36 months postdiagnosis continuous hmo membership ( n = 8,540 ) . a diabetes diagnosis was assigned to those who met diabetes registry criteria : documentation of an inpatient or outpatient type 2 diabetes diagnosis , fasting plasma glucose > 125 mg / dl , or diabetes medication dispensed . a diagnosis was considered new if the patient had not met the qualifying criteria in the 12 months before diabetes registry entry . we excluded 3,833 patients with a severe illness or condition associated with unintentional weight change in the 12 months preperiod or during trajectory : 69.0% ( n = 2,645 ) with cancer , 12.0% ( n = 460 ) on home oxygen , 5.0% ( n = 191 ) with a pregnancy , 5.0% ( n = 193 ) with amputation(s ) , and 9.0% ( n = 344 ) with any of the following conditions : hiv , nutritional deficiency , bariatric surgery , dialysis , hospice , or care facility stay > 30 days and bmi < 20 kg / m ( n = 4,707 remained ) . finally , we included only those with a weight measurement at baseline and at least five weight measurements in the 3 years postdiagnosis ( to explore differently shaped weight - change curves ) ; the final weight measurement had to occur 30 to 36 months postindex ( final n = 2,574 patients ) . those excluded as a result of weight requirements were younger ( 54.5 vs. 56.3 years ; p < 0.001 ) and more likely to be male ( 52.3 vs. 47.3% ; p < 0.001 ) and have a higher a1c ( 8.2 vs. 8.0% ; p = 0.023 ) , but they did not have significantly different blood pressure . the primary outcomes were above - goal a1c ( 7% ) and above - goal blood pressure ( 130/80 mmhg ) ( 10 ) during the 4th year after the index date , using mean values . to adjust for baseline a1c , we defined baseline as a1c measures that were taken during year 1 because few participants had pre diabetes diagnosis a1c measures . additional analyses considered only patients with a1c measured in a 3-month window around the index date . baseline blood pressure ( above goal ) was based on mean blood pressure in the 12 months before index . the 3-year weight was the measure collected closest to the end of the 30- to 36-month interval . we included a group of covariates traditionally associated with weight or weight change ( 1113 ) : age at index date ( 11 ) , sex ( 12 ) , whether the individual was in a group at race - risk for obesity ( black , hispanic , native american , and pacific islander , combined ) ( 12 ) , medicaid enrollment , and family income < $ 40,000 per year ( 11 ) . race data were available for 77% of patients . to approximate missing race data and to assign family income , we used participants mailing addresses to obtain census tract block data . we used baseline weight and any available height to determine baseline bmi and obesity ( bmi 30 kg / m ) status ( 1 ) . we used the mean number of unique medications dispensed in the prediagnosis period as a measure of disease burden ( 14 ) . we noted baseline diagnoses that could affect or be affected by weight or weight change : hypertension , dyslipidemia , cardiovascular disease ( excluding congestive heart failure ) , microvascular disease ( retinopathy , neuropathy , and nephropathy , combined ) , depression , and conditions that could interfere with activity ( asthma , chronic obstructive pulmonary disease , and arthritis , combined ) ( 13 ) . we used the following diabetes medication categories for any single medication dispensed for > 30 days during year 4 : sulfonylureas for patients dispensed sulfonylureas ( but not metformin ) , metformin for those dispensed metformin ( but not sulfonylureas ) , sulfonylureas and metformin for those dispensed both , thiazolidinedione , acarbose , and repaglinide . insulin use was indicated for those to whom any insulin was dispensed during year 4 . we used the blood pressure medication categories beta blocker , diuretic , ace inhibitor , angiotensin receptor blocker , or other antihypertensive medication for those dispensed for > 30 days during year 4 . individual weight trajectories were estimated using growth curve analyses ( multilevel modeling ) with hlm 6.0 . time formed the first level of the model , with weight as the dependent variable . the intercept and slope parameters describing individual weight trajectories were entered into a hierarchical cluster analysis , using ward 's method in spss 15.0 , to identify groups of patients with similar weight trajectories . multiple logistic regression models estimated the unadjusted effect of membership in a weight - trajectory cluster on above - goal a1c and blood pressure in year 4 , as well as the effect while controlling for factors that were statistically significant in univariate analyses and are known to affect glycemic and blood pressure control ( 3 ) . adjusted model one controlled for age , sex , and baseline a1c or blood pressure control , and model two added diabetes or blood pressure medication use at year 4 . the weight loss the study was conducted at kaiser permanente northwest ( kpnw ) , a not - for - profit hmo in the pacific northwest with 480,000 members . electronic medical records include patient weight , blood pressure , height , smoking status , diagnoses , treatment procedures , medications , and laboratory results . the kpnw diabetes registry has been shown to be 99.5% specific and 99% sensitive for diabetes diagnosis compared with chart review ( 9 ) . kpnw members with diabetes are demographically and clinically similar to the national population of patients with diabetes ( 9 ) . the study site 's clinical guidelines for diabetes care are consistent with prevailing guidelines ( 10 ) . guidelines recommend lifestyle management for all people with diabetes and a stepped - care approach to medication use for control of risk factors . most newly diagnosed members attend diabetes classes , and hmo weight - related health - education classes are available for a fee . this retrospective cohort study evaluated 3-year weight trajectory patterns in subjects aged 2175 years and newly diagnosed with type 2 diabetes , as well as the patterns effects on a1c and blood pressure in year 4 . we identified all men and women aged 2175 years with any evidence of type 2 diabetes ( n = 38,430 ) . we then limited the population to those with newly diagnosed type 2 diabetes from 1 january 1997 to 31 december 2002 ( n = 17,403 ) and then further limited it to those with 12 months pre- and 36 months postdiagnosis continuous hmo membership ( n = 8,540 ) . a diabetes diagnosis was assigned to those who met diabetes registry criteria : documentation of an inpatient or outpatient type 2 diabetes diagnosis , fasting plasma glucose > 125 mg / dl , or diabetes medication dispensed . a diagnosis was considered new if the patient had not met the qualifying criteria in the 12 months before diabetes registry entry . we excluded 3,833 patients with a severe illness or condition associated with unintentional weight change in the 12 months preperiod or during trajectory : 69.0% ( n = 2,645 ) with cancer , 12.0% ( n = 460 ) on home oxygen , 5.0% ( n = 191 ) with a pregnancy , 5.0% ( n = 193 ) with amputation(s ) , and 9.0% ( n = 344 ) with any of the following conditions : hiv , nutritional deficiency , bariatric surgery , dialysis , hospice , or care facility stay > 30 days and bmi < 20 kg / m ( n = 4,707 remained ) . finally , we included only those with a weight measurement at baseline and at least five weight measurements in the 3 years postdiagnosis ( to explore differently shaped weight - change curves ) ; the final weight measurement had to occur 30 to 36 months postindex ( final n = 2,574 patients ) . those excluded as a result of weight requirements were younger ( 54.5 vs. 56.3 years ; p < 0.001 ) and more likely to be male ( 52.3 vs. 47.3% ; p < 0.001 ) and have a higher a1c ( 8.2 vs. 8.0% ; p = 0.023 ) , but they did not have significantly different blood pressure . the primary outcomes were above - goal a1c ( 7% ) and above - goal blood pressure ( 130/80 mmhg ) ( 10 ) during the 4th year after the index date , using mean values . to adjust for baseline a1c , we defined baseline as a1c measures that were taken during year 1 because few participants had pre diabetes diagnosis a1c measures . additional analyses considered only patients with a1c measured in a 3-month window around the index date . baseline blood pressure ( above goal ) was based on mean blood pressure in the 12 months before index . the 3-year weight was the measure collected closest to the end of the 30- to 36-month interval . we included a group of covariates traditionally associated with weight or weight change ( 1113 ) : age at index date ( 11 ) , sex ( 12 ) , whether the individual was in a group at race - risk for obesity ( black , hispanic , native american , and pacific islander , combined ) ( 12 ) , medicaid enrollment , and family income < $ 40,000 per year ( 11 ) . race data were available for 77% of patients . to approximate missing race data and to assign family income , we used participants mailing addresses to obtain census tract block data . we used baseline weight and any available height to determine baseline bmi and obesity ( bmi 30 kg / m ) status ( 1 ) . we used the mean number of unique medications dispensed in the prediagnosis period as a measure of disease burden ( 14 ) . we noted baseline diagnoses that could affect or be affected by weight or weight change : hypertension , dyslipidemia , cardiovascular disease ( excluding congestive heart failure ) , microvascular disease ( retinopathy , neuropathy , and nephropathy , combined ) , depression , and conditions that could interfere with activity ( asthma , chronic obstructive pulmonary disease , and arthritis , combined ) ( 13 ) . we used the following diabetes medication categories for any single medication dispensed for > 30 days during year 4 : sulfonylureas for patients dispensed sulfonylureas ( but not metformin ) , metformin for those dispensed metformin ( but not sulfonylureas ) , sulfonylureas and metformin for those dispensed both , thiazolidinedione , acarbose , and repaglinide . insulin use was indicated for those to whom any insulin was dispensed during year 4 . we used the blood pressure medication categories beta blocker , diuretic , ace inhibitor , angiotensin receptor blocker , or other antihypertensive medication for those dispensed for > 30 days during year 4 . individual weight trajectories were estimated using growth curve analyses ( multilevel modeling ) with hlm 6.0 . time formed the first level of the model , with weight as the dependent variable . we used both linear and quadratic models to determine best fit for the data . the intercept and slope parameters describing individual weight trajectories were entered into a hierarchical cluster analysis , using ward 's method in spss 15.0 , to identify groups of patients with similar weight trajectories . multiple logistic regression models estimated the unadjusted effect of membership in a weight - trajectory cluster on above - goal a1c and blood pressure in year 4 , as well as the effect while controlling for factors that were statistically significant in univariate analyses and are known to affect glycemic and blood pressure control ( 3 ) . adjusted model one controlled for age , sex , and baseline a1c or blood pressure control , and model two added diabetes or blood pressure medication use at year 4 . when estimating weight trajectories , we found that the quadratic model fit significantly better than the linear model ( p < 0.0001 ) . therefore , three variables representing an individual 's weight trajectory were included in the cluster analysis : intercept ( estimated baseline weight ) , linear slope , and quadratic slope . the group with a higher stable weight ( n = 418 ; 16.2% ) and the group with a lower stable weight ( n = 1,542 ; 59.9% ) largely maintained their weights . the weight - gain group ( n = 300 ; 11.7% ) began at a mean weight of 107.8 kg and gained weight until about 18 months , reaching a mean of 114.7 kg ( 6.4% gain ; p < 0.001 ) , followed by a weight loss ; ending mean weight was near baseline . the weight - loss group ( n = 314 ; 12.2% ) began at a mean weight of 109.3 kg and lost weight until about 18 months , reaching a mean of 98.6 kg ( 9.8% loss ) , followed by a regain to approximately baseline weight . notably , the weight - gain and weight - loss groups began and ended at similar mean weights . the four groups were significantly different with respect to age , sex , baseline weight and bmi , race , diagnosed depression , and hypertension and blood pressure . of note is that the mean baseline ( year 1 ) a1c and the percent above goal were significantly different across groups and lower in the weight - loss compared with the weight - gain group . table 2 summarizes the unadjusted a1c and blood pressure results in year 4 by group . the weight - loss group had the lowest percentage of individuals with above - goal a1c ( by year 4 , the difference between it and other groups had become more prominent ) and blood pressure and more favorable means and distributions of both measures . metformin use in the weight - loss group remained stable ( 19.4% in year 1 vs. 23.6% in year 4 ) , whereas use in the weight - gain group increased from 18.3% in year 1 to 41.3% in year 4 ( data not shown ) . table 3 presents the logistic regression models comparing above - goal a1c in year 4 in the three other weight - change trajectories with that in the weight - loss group ( limited to the 1,911 [ 74.2% ] patients who had one or more a1c measures in both years 1 and 4 ) . in the three models , the likelihood of above - goal a1c remained significantly higher among the groups with higher stable weight , lower stable weight , and weight gain than in the weight - loss group . the magnitude of the effect is diminished by adding the covariates . in the fully adjusted model 2 , those with higher stable weight were 1.7 times more likely ( 95% ci 1.12.5 ) to have above - goal a1c than those in the weight - loss group , those with lower stable weight were 1.5 times more likely ( 1.12.1 ) , and those with weight gain were 1.8 times more likely ( 1.22.7 ) . each year of age reduced the odds of above - goal a1c by 3% ( odds ration [ or ] 0.97 [ 95% ci 0.960.98 ] ) . those with above - goal a1c at year 1 were 2.4 times more likely to be above goal at year 4 ( 95% ci 2.74.0 ) . when analyses were restricted to 1,599 patients with a true baseline a1c measure , the odds of above - goal a1c in year 4 were 2.3 ( 95% ci 1.43.7 ) times higher in the weight - gain group than in the weight - loss group . also , baseline bmi alone ( vs. trajectory membership ) did not significantly predict above - goal a1c in year 4 ( data not shown ) . table 3 also presents logistic regression models comparing above - goal blood pressure in year 4 in the other weight - change trajectories to blood pressure in the weight - loss group ( limited to the 2,410 [ 93.6% ] patients who had one or more blood pressure measures in year 4 ) . in the fully adjusted model 2 , those with higher stable weight were 1.8 times more likely ( 95% ci 1.32.6 ) than those in the weight - loss group to have above - goal blood pressure , and those with weight gain were 1.5 times more likely ( 1.12.1 ) . each year of age increased the odds of being above goal by 2% ( or 1.02 [ 95% ci 1.011.03 ] ) . those with above - goal blood pressure at year 1 were 2.9 times more likely to be above goal at year 4 ( 95% ci 2.43.6 ) . we found that 12.2% of people with type 2 diabetes in our population had a mean 3-year weight - change trajectory that included a clinically significant ( 9.8% at 18 months ) ( 2 ) mean weight loss . despite weight regain during the 3-year period , those who initially lost weight had improved glycemic and blood pressure control in year 4 compared with that in groups with stable or weight - gain trajectories . these findings suggest that , even in the face of weight regain ( 15 ) , losing weight can have long - lasting benefits in type 2 diabetes . the therapeutic advantage achieved through weight loss is exceedingly important given the close connection between glycemic and blood pressure control ( especially in the first years postdiagnosis ) and cardiovascular outcomes ( 16,17 ) . although helping patients achieve weight loss can be overwhelming ( 18 ) , physicians can feel encouraged by the weight trajectories we observed in free - living people with type 2 diabetes during the 3 years after initial diagnosis . some people achieved weight loss despite the fact that the study site , similar to many communities ( 18 ) , directs fewer resources to weight loss than to monitoring and medications . practitioners frustrated by the frequency of weight regain ( 15 ) may be reinvigorated by our finding that weight regain in diabetes may not imply lack of therapeutic benefits of weight loss . the weight - loss group , on average , began regaining at about 18 months . this suggests that the first months postdiagnosis may provide a window to capitalize on patient and clinician motivation by actively applying weight - loss interventions . recent findings from the look ahead weight loss in diabetes study revealed that the intensive lifestyle intervention group lost , on average , 8.6% of their initial weight at 1 year , compared with 0.7% in the education control group ( 3 ) . the magnitude of weight change noted in our community weight - losing cohort was similar . at year 4 , the absolute a1c and blood pressure differences between those who lost or gained weight were small but similar to differences observed between intervention and control subjects in look ahead ( 3 ) . the a1c effects seen here are clinically significant : prior studies have concluded that every percentage point reduction in mean a1c correlates with a 37% reduction in risk of microvascular complications and a 21% reduction in risk of any diabetes - related end point and diabetes - related deaths . risk of death from ischemic heart disease and stroke also increases progressively and linearly starting from blood pressure levels as low as 115/75 mmhg ( 20 ) . last , our models controlling for medication use in year 4 may have provided conservative estimates of effects of weight trajectories on a1c control , in that diabetes medication use likely also affects weight trajectories ( 21 ) . the weight - loss group had little change in metformin use ( often associated with weight loss ) ( 21 ) . thus , medication use patterns can not explain the improved trajectory and a1c patterns in the weight - loss group . the study was conducted at one hmo in two states , so findings may not be generalizable to other settings . we studied only survivors , so we do not know weight - change patterns for everyone or how they related to outcomes . however , our study was strengthened by access to many measures taken in a large group of community - based diabetes patients , including diagnostic data that might suggest unintentional weight change . our data were collected during clinical care ; thus , weight and other measurements may not have been as precise or complete as they would be during a clinical trial . for example , we did not have a true baseline a1c on all patients and , instead , used year 1 findings . however , this was a conservative approach , and findings were largely unchanged when analyses were restricted to those with a baseline measure . we did not evaluate possible mechanisms that might explain the improved a1c and blood pressure control observed in the weight - loss group . the lasting benefit , in spite of weight regain , may derive from increased insulin sensitivity remaining from weight loss ( 22 ) ; mechanisms related to metabolic memory ( 23 ) ; lifestyle changes accompanying weight loss , such as improved diet or increased activity ; or other unmeasured factors that differed among the weight - trajectory groups . interestingly , the strength of the trajectory method is highlighted by the finding that baseline bmi alone did not significantly predict above - goal a1c in year 4 . we conclude that , in this analysis , a weight - loss trajectory predicted improved glycemic and blood pressure control when compared with stable - weight or weight - gain trajectories . in light of previously reported positive effects of weight loss on therapeutic outcomes in people with diabetes ( 3,17,19 ) and our added findings of the natural history of weight loss and outcomes in diabetes in the community , more focus should be placed on helping clinicians implement programs to manage weight trajectories in new diabetic patients . Output:	objective weight loss in type 2 diabetes is undisputedly important , and data from community settings are limited . we evaluated weight change and resulting glycemic and blood pressure control in type 2 diabetic patients at an hmo.research design and methods using electronic medical records , this retrospective cohort study identified 2,574 patients aged 2175 years who received a new diagnosis of type 2 diabetes between 1997 and 2002 . we estimated 3-year weight trajectories using growth curve analyses , grouped similar trajectories into four categories using cluster analysis , compared category characteristics , and predicted year-4 above - goal a1c and blood pressure by group.resultsthe weight - trajectory groups were defined as higher stable weight ( n = 418 ; 16.2% ) , lower stable weight ( n = 1,542 ; 59.9% ) , weight gain ( n = 300 ; 11.7% ) , and weight loss ( n = 314 ; 12.2% ) . the latter had a mean weight loss of 10.7 kg ( 9.8% ; p < 0.001 ) by 18 months , with near - complete regain by 36 months . after adjusting for age , sex , baseline control , and related medication use , those with higher stable weight , lower stable weight , or weight - gain patterns were more likely than those who lost weight to have above - goal a1c ( odds ratio [ or ] 1.66 [ 95% ci 1.122.47 ] , 1.52 [ 1.082.14 ] , and 1.77 [ 1.152.72 ] , respectively ) . those with higher stable weight or weight - gain patterns were more likely than those who lost weight to have above - goal blood pressure ( 1.83 [ 1.312.57 ] and 1.47 [ 1.032.10 ] , respectively).conclusions a weight - loss pattern after new diagnosis of type 2 diabetes predicted improved glycemic and blood pressure control despite weight regain . the initial period postdiagnosis may be a critical time to apply weight - loss treatments to improve risk factor control .
PubmedSumm118893	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: supplementary material is available for this article at 10.1007/s13659 - 013 - 0053 - 4 and is accessible for authorized users . Output:	phytochemical investigation of the aerial parts of dodonaea viscosa led to the isolation of six new compounds including four isoprenylated flavonoids , dodovisones a - d ( 14 ) , and two clerodane diterpenoids , dodovislactones a and b ( 5 and 6 ) . their structures were established by extensive spectroscopic analysis . electronic supplementary materialsupplementary material is available for this article at 10.1007/s13659 - 013 - 0053 - 4 and is accessible for authorized users .
PubmedSumm118894	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: since the successful development of methods to synthesize fullerenes in macroscopic quantities , the properties of metal - doped fullerene solids and their potential applications have been studied . early experiments on fullerides doped with alkali ( a ) metals revealed metal insulator transitions and the appearance of superconductivity in potassium - doped fullerides below tc = 18 k. various crystal structures form depending on the dopant concentration which may be as large as 12:1 in li12c60 . superconductivity , however , is restricted to the a3c60 fulleride salts in which the alkalis transfer their valence electrons to the lowest unoccupied triply degenerate molecular orbital of t1u symmetry , resulting in a half - filled conduction band of c60 . the superconducting transition temperature in binary a1b2c60 fulleride salts ( a , b = alkali metal ) indeed , the highest transition temperature of any alkali - doped fulleride has been reported for cs3c60 which is an insulator at ambient pressure but becomes superconducting below tc = 38 k at elevated pressure without changing its body - centered cubic structure . in a recent report we presented ion abundances of ( c60)mcsn cations prepared in the gas phase by electron ionization of helium nanodroplets doped with c60 and cs . a key finding was that ( c60)mcsn ions ( m 6 ) are particularly abundant if they contain n = 6 m + 1 cesium atoms ; ( c60)mcsn dications were abundant ( with the exception of ( c60)4csn ) if n = 6 m + 2 . by and large these results were consistent with earlier photoionization experiments by martin and co - workers involving potassium and rubidium which indicated that up to six alkali metal atoms per c60 transfer their valence electrons into the t1u orbital , resulting in particularly stable c60a6 building blocks . one or two additional alkali ions are needed to provide the net charge of the mono- and dications , respectively . c60 powder is , in fact , known to react rapidly with liquid alkalis to form the body - centered cubic c60a6 phase . evidence for c60a6 building blocks also appeared in abundance distributions of ( c60)mnan ( m 10 ) and ( c60)mnan ( m 5 ) , consistent with reports by martin and co - workers for m 3 and photodissociation data reported by pellarin et al . for m 2 . interestingly , the photodissociation experiments by pellarin et al . revealed another pattern , namely , enhanced abundance of c60na3 and ( c60)2na5 . the authors noticed that these species marked the onset of cluster ion distributions in spectra reported by martin and co - workers and proposed the existence of stable c60na2 units in which the fullerenes are covalently bonded through a [ 2 + 2 ] cycloaddition . similar onsets at c60a3 and ( c60)2a5 with a = k or rb were noticed in photodissociation experiments by kappes and co - workers . for c60 trimers , however , kappes and co - workers reported that ( c60)3a8 ( a = k , rb ) formed the onset whereas martin et al . identified ( c60)3na7 as onset . a different experimental approach was pursued by kern and co - workers who heated neutral c60-potassium clusters in helium gas . the preferred composition of clusters containing four or fewer c60 that survived at 900 k for about 1 ms was ( c60k2)m . in the present work we have doped helium nanodroplets with much smaller amounts of cesium than in our previous experiments , resulting in ions containing as many as 10 c60 and between 1 and about 12 cs atoms . finding is a pronounced maximum in the abundance of ( c60)mcs3 cations and anions for all values of m except for c60csn whose abundance declines very rapidly with increasing n. another , weaker anomaly appears at ( c60)mcs5 . the fact that these anomalies are independent of m and the charge state might suggest that they are due to particularly stable cesium cluster ions that are favored irrespective of the number of fullerenes . we observe , indeed , corresponding anomalies at n = 3 and 5 in abundance distributions of neat csn and csn , consistent with theoretical predictions that these ions are particularly stable . however , in the literature we find no support for the proposed presence of stable alkali trimer and pentamer units in neutral or charged ( c60)man . we also report the dependence of the abundance of ( c60)mcs3 anions on the electron energy which shows an intriguing alternating pattern as m increases . abundanpce distributions of ( c60)mcsn cations containing up to seven c60 are displayed in figure 1 . the staggered distributions have been individually normalized ; their baselines and corresponding m values are indicated along the ordinate on the right . error bars are plotted if they exceed the size of the symbols . for m = 1 we observe a steep drop in the abundance after n = 3 ; for larger m values n = 3 forms a local maximum . this maximum persists up to m = 10 ( not shown ) , the largest value for which statistically significant data exist . a weaker local maximum is observed at n = 5 , especially for m = 2 , 3 , and 4 . the distributions are individually normalized for each value of m and vertically offset ( staggered ) ; baselines are indicated on the ordinates . maxima or abrupt drops occur at n = 3 and 5 for all but the largest m values . we did not notice these features in our previous report on heavily coated c60 cluster cations , but close inspection of figure 1 in that report reveals a steep rise in the ion abundance of ( c60)mcsn from n = 4 to 5 followed by a plateau , for m = 2 , 3 , and 4 . the abundance of ions with n 4 was simply too small to discern any anomalies . figure 2 presents staggered abundance distributions of ( c60)mcsn anions formed by electron attachment at 13 ev , for m 7 . they are surprisingly similar to those of cations , with ( c60)mcs3 forming local maxima or , for m = 2 and 3 , featuring abrupt drops . the abundance of c60csn decreases very rapidly with n ; the presence or absence of anomalies at n = 3 and 5 can not be assessed . staggered , normalized abundance distributions of ( c60)mcsn for m 7 , recorded with an electron energy of 13 ev . maxima or abrupt drops occur at n = 3 and 5 for 2 m 6 . data were extracted from mass spectra recorded without c60 doping . for csn , similar distributions were deduced from droplets co - doped with c60 but the yield of csn was very weak in the presence of c60 . a logarithmic scale was chosen for the ordinate because the abundance of cations and anions decreases rapidly with n. anions display strong maxima at n = 3 and 5 . cs3 is nearly 4 times more abundant than cs2 ; cs5 is 5 times more abundant than cs4 . the most pronounced anomaly in the distribution of cations occurs at cs9 ; less pronounced drops appear at cs3 and cs5 . it is worth mentioning that abundance distributions of csn extracted from a liquid - metal ion source show the same anomalies but the contrast is much larger , roughly 1:10 for the abundance ratio of csn+1 versus csn , for n = 3 , 5 , 9 . the contrast ratio depends on instrumental factors such as the time window during which hot cluster ions are allowed to evaporate and whether or not ions produced by unimolecular dissociation after acceleration are detected or rejected . ( b d ) theoretical dissociation energies of cesium cluster cations , neutrals , and anions , deduced from published total binding energies . the dependence of the ( c60)mcs3 ion abundance on the electron energy is displayed in figure 4a for 1 m 7 . we selected this ion series ( with n = 3 ) because of its prominent appearance in figure 2 . the staggered distributions are normalized ; baselines and values of m are indicated along the ordinate . surprisingly , the patterns alternate with increasing m. ions with odd values of m feature a broad maximum that gradually shifts from 10 ev for m = 1 to 15 ev for m = 5 ; ions with even m feature an even broader maximum around 23 ev . for m = 7 and larger ( not shown ) , the distributions become rather similar , exhibiting a maximum between 15 and 20 ev . dependence of the anion abundance on electron energy , for ( c60)mcs3 with m 7 ( a ) and cs3 and cs5 ( b ) . data are normalized and staggered ; individual baselines are indicated along the ordinate . the energy dependences of cs3 and cs5 are shown ( staggered and normalized ) in figure 4b . note that the csn data were recorded in experiments that did not involve co - doping with c60 . in a recent report we had measured abundance distributions of ( c60)mcsn cations containing up to six c60 and several dozen cs . local maxima in the ion abundance suggested that ions with n = 6 m + 1 are particularly stable . the findings were consistent with earlier research by martin and co - workers on potassium- and rubidium - doped fullerene aggregates ; the authors suggested the presence of c60a6 building blocks in which the alkali metal atoms transfer their valence electrons to the 3-fold degenerate lowest unoccupied orbital ( t1u ) of the fullerene , forming essentially ionic bonds . subsequent theoretical studies of sodium and potassium adsorbed on c60 have supported this interpretation . further support for the model comes from a shift of the anomalies to n = 6 m + 2 for ( c60)mcsn dications and to n = 6 m + 3 for x(c60)mcsn where x = h2o or co2 . the results in the present study pertain to much weaker doping , i.e. , smaller values of n ; they can not possibly reveal the existence of c60a6 building blocks . instead , from observation of particularly abundant ( c60)mcs3 and , to a lesser degree , ( c60)mcs5 ions , either positively or negatively charged , one might conclude that cs3 and cs5 ions are particularly stable entities that form irrespective of the environment . note that the prominence of cs3 and cs5 could also be augmented by particularly weak binding in cs4 and cs6 . this interpreation is apparently supported by the enhanced ion abundances of bare cs3 and cs5 cluster ions ; see figure 3a , as well as theoretical studies of these species . ali et al . have used density functional theory ( dft ) to determine the structure and electronic properties ( including ionization energies and electron affinities ) of csn and csn , n 10 . dissociaton energies dn , deduced from plots showing computed total energies in ali s work are plotted in figure 3b and figure 3c for cationic and neutral clusters , respectively . also applied dft to compute total energies of csn , csn , and csn , n 8 . dissociation energies derived from their graphs are displayed in figure 3b , figure 3c , and figure 3d , respectively . also included in figure 3c are dissociation energies computed for neutral csn , n 20 , by assadollahzadeh et al . several other theoretical studies of neutral csn have focused on much larger clusters ; those results are not included in figure 3 . dissocation energies derived from florez s work reveal that cs3 and cs5 enjoy enhanced stability . the enhanced stability of cs3 does not appear in ali s work which has been criticized by florez et al . for using an extremely small basis set and neglecting relativistic effects . within the spherical jellium approximation cs3 has enhanced stability because it features a closed s shell . the computed high stability of cs3 is supported by photoelectron spectra which show that its vertical detachment energy is nearly twice that of cs2 . we note in passing that the anomaly in the abundance and computed stability of cs9 ( figure 3a and figure 3b ) is expected within the spherical jellium model because this ion would have a closed 1s1p configuration . however , a corresponding anomaly for anions , at cs7 , is not reflected in the ion abundance ( figure 3a ) and only weakly in the computed stability ( figure 3d ) . however , the hypothesis of intact cs3 and cs5 entities in c60 aggregates of either charge state finds little support from other investigations of neutral or charged c60-alkali complexes . one should emphasize though that previous work mostly pertains to the lighter alkalis ( a = li , na , k ) and that their properties are still debated . one topic of interest has been the nature of bonding which is dominantly ionic . have computed the susceptibility and electric dipole moment of c60 complexed with one alkali atom . for cs , rb , and k the mulliken charge on the alkali is very close to + 1.00e but it decreases to about 0.90e for na and 0.70e for li . qualitatively the same decreasing trend has been reported by other researchers for li , na , k. for c60 doped with multiple alkalis , however , charge transfer decreases with increasing n , thus decreasing the coulombic repulsion between the ions . furthermore , the above - mentioned trend reverses and charge transfer gradually increases from k to li . another topic of interest has been the energetically preferred adsorption site of a single alkali . density functional theory studies find that na and k alkali atoms preferentially adsorb at a hexagonal site ( note that some studies mentioned here refer to charged complexes ) . c60-lithium complexes have received the greatest attention because of their potential application as a lightweight medium for hydrogen storage , but their properties do not seem to be characteristic of c60 complexed with heavier alkalis ; they will not be considered any further in this discussion . the topic of greatest relevance to the present work is the structure and stability of c60 dressed with several alkali atoms . theoretical studies reveal a delicate balance between coulomb repulsion between atomic ions favoring uniform ( homogeneous ) coverage and metallic bonding favoring island formation , i.e. , segregation . conflicting results have been found for c60nan . on the basis of mass spectra and photoelectron spectra of c60nan , n 12 , palpant et al . their conclusion is supported by a dft study of c60nan by wang et al . , although these authors find another preferred motif , a tetrahedral na4 . for n = 4 , 6 , 7 , 9 the ground state structure consists of a single three - dimensional sodium cluster , while for n = 5 and 8 two isolated clusters form on opposite sides of the fullerene . researchers at the university of lyon have measured the electric susceptibility of neutral c60nan in a molecular beam deflection experiment . strong deflection was attributed to complete segregation , i.e. , formation of a single sodium droplet for all values of n. in later work though , supported by dft studies , it was concluded that the first 8 sodium atoms spread uniformly over the c60 surface . in a subsequent dft study rabilloud concluded that up to 12 sodium atoms prefer to form distinct tetrahedral islands . the relevance of results pertaining to c60-sodium complexes for the interpretation of our c60-cesium data may be questioned , but work on heavier alkalis is scarce . in a dft study of c60k12 rabilloud the appearance of electronic shell structure in abundance distributions of c60 heavily coated with cesium has stimulated a few theoretical studies of this core shell system , but they are of little relevance to the present discussion . our group has recently investigated adsorption of hydrogen on neutral and cationic c60cs . dft calculations including empirical dispersion correction and harmonic vibrational zero - point corrections resulted in dissociation energies of 0.793 ev for c60cs . in another dft study we have concluded that the lowest energy configuration of neutral c60cs2 consists of two cs atoms located on opposite sites of c60 . the various studies summarized above provide no support for the hypothesis of stable cs3 and cs5 entities ; we therefore seek an alternative explanation . as mentioned in the introduction , pellarin et al . reported evidence for particularly stable c60na3 and ( c60)2na5 based on mass spectrometric expereriments in which c60-sodium complexes were deliberately heated by the ionizing laser . the authors pointed out that related features appeared in mass spectra reported by martin s group in form of abrupt onsets at c60na3 , ( c60)2na5 , and ( c60)3na7 . conjectured that ( c60)2na5 and ( c60)3na7 might dissociate by losing a c60na2 unit . although this reaction could not be experimentally observed , the hypothesis of stable c60a2 units has been beautifully confirmed by kern and co - workers for a = potassium . the researchers thermalized neutral c60-potassium clusters for about 1 ms in hot helium gas ; the clusters were then softly ionized by one - photon ionization . at temperatures of 900 k they observed abundance distributions that sharply peaked at ( c60k2)m for m 4 . their dft calculations of c60kn and ( c60)2kn at finite temperatures revealed that ( c60)2k4 is , indeed , thermodynamically most stable among all ( c60)2kn species for n 6 . the authors emphasized that ( c60k2)m owe their superior stability to their high entropy rather than to closure of any electronic or geometric shells . the computed ground state structure of c60k2 features two alkali atoms at opposite hexagonal sites , whereas that of ( c60)2k4 consists of a c60 dimer with the four alkali atoms wrapped around its waiste . this configuration is also favored when atoms or molecules are physisorbed on ( c60)2 , but coulomb repulsion between adsorbed alkali cations tends to destabilize it . in fact , the most stable geometries computed for ( c60)2k5 and ( c60)2k6 have two k atoms at opposite sites of the ( c60)2 dumbbell axis . the computational results for c60k2 and ( c60k2)2 provide little guidance as to the structures of ( c60k2)3 and ( c60k2)4 and the reason for their superior thermodynamic stability . where are the cesium atoms located in clusters containing more than two c60 ? do the three cesium atoms in the magic ( c60)mcs3 ( m 2 ) prefer sites that are separated as far as possible , as computed for c60k2 , or do they cluster in groove sites as computed for ( c60k2)2 ? and why do not we observe an anomaly at the presumably magic ( c60)3cs7 ? perhaps , one may argue that the low cesium concentration in our experiments renders the observation of this ion impossible and the prominence of ( c60)mcs3 and ( c60)mcs5 is owed to the well - known odd even effect in the stability of alkali clusters . a look at figure 1 makes this explanation unconvincing ; the falloff in the ion abundance beyond the magic ( c60)3cs5 is gradual and smooth . we can think of two factors that might cause the differences between our data and previous reports : ( i ) differences between cesium and its lighter and smaller cousins and ( ii ) differences in the way by which aggregates are synthesized and ionized . in previous studies , aggregates were formed in gas - phase collisions between c60 and alkali atoms ( sometimes brought into the gas phase by laser ablation ) and subsequently ionized by photons . in the present study as well as our earlier work aggregates were synthesized in helium droplets and ionized by electrons . in many cases mass spectra resulting from these different approaches are very similar . superfluid helium does not wet bulk cesium ; even large neutral cesium clusters will not be solvated by helium nanodroplets but rather remain on the surface . the situation changes , though , in the presence of other solutes that are highly polarizable . recently we could show that neutral c60 or c60 aggregates embedded in a droplet will pull neutral cesium clusters into the droplet by a harpooning mechanism , the only exception being atomic cesium . although not discussed in that work , it seems likely that atomic cesium will be pulled into the droplet once a c60an aggregate has formed because the electric polarizability of c60an is an order of magnitude larger than that of c60 . if a cs dimer but not a cs atom would be pulled into a droplet containing a c60csn aggregate , an interesting odd even effect would appear where c60-doped helium droplets containing n cs atoms would consist of solvated ( c60)mcsn if n is even but solvated ( c60)mcsn1 plus a cs atom on the surface if n is odd . perhaps the most intriguing and hardest to explain feature in our data is the peculiar pattern in the energy dependence of ( c60)mcs3 anions which alternates with increasing m ; see figure 4 . the spectrum of c60cs3 with its main maximum around 10 ev is not unlike those of c60 and ( c60)2 obtained from c60-doped helium nanodroplets which feature a broad maximum around 510 ev plus a weaker one at about 25 ev . the spectra of ( c60)2cs3 and ( c60)4cs3 , however , are missing the 10 ev resonance . if the ( c60)m aggregates were van der waals bound , this odd even effect would be difficult to explain . but are they ? pellarin et al . have proposed that the fullerenes are covalently bonded through a [ 2 + 2 ] cycloaddition . they did not explain how that reaction would be initiated but dimerization of fullerenes in ( c60)m may provide a clue toward the observed odd even effect . electron ionization of helium droplets doped with c60 and cesium results in mass spectra that consistenly feature maxima in the abundance of positively and negatively charged ( c60)mcs3 and ( c60)mcs5 for a range of m values . this also holds true for m = 0 , i.e. , for bare cesium ions . the most straightforward explanation , the presence of highly stable cs3 and cs5 clusters , is not supported by previous work involving complexes of c60 with lighter alkalis . the features are reminiscent of features in cationic spectra of c60 complexed with lighter alkalis ( a ) which point to particularly stable c60a2 building blocks , but we do not observe a corresponding enhancement of the abundance for ( c60)3cs7 or ( c60)4cs9 . also , it is not clear why anions should show the same magic numbers as cations . perhaps the most puzzling finding is a pattern in the energy dependence of ( c60)mcs3 that alternates with increasing m. odd even effects are well - known for monovalent metal clusters but not for presumably van der waals bound c60 aggregates . further experiments are needed , preferably involving lighter alkalis that are more amenable to high - level theoretical investigations . Output:	we report on the formation and ionization of cesium and c60cs clusters in superfluid helium nanodroplets . size distributions of positively and negatively charged ( c60)mcsn ions have been measured for m 7 , n 12 . reproducible intensity anomalies are observed in high - resolution mass spectra . for both charge states , ( c60)mcs3 and ( c60)mcs5 are particularly abundant , with little dependence on the value of m. distributions of bare cesium cluster ions also indicate enhanced stability of cs3 and cs5 , in agreement with theoretical predictions . these findings contrast with earlier reports on highly cs - doped cationic fullerene aggregates which showed enhanced stability of c60cs6 building blocks attributed to charge transfer . the dependence of the ( c60)mcs3 anion yield on electron energy shows a resonance that , surprisingly , oscillates in strength as m increases from 1 to 6 .
PubmedSumm118895	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: successful organ regeneration relies on organized and timely cross - talk among distinct cell niches . insights into the molecular basis of such cross - talk can be obtained by examining the mammalian hair follicle , which serves as an example of such collaboration , notably between keratin 15 ( k15 ) epithelial stem cells ( epscs ) located within the bulge and secondary hair germ and mesenchymal cells located within the dermal papilla ( dp ) and dermal sheath ( cotsarelis et al . , 1990 ; millar , 2002 ; liu et al . , 2003 ; rendl et al . , 2008 ) . the dp is embedded within the hair bulb during the anagen phase and forms a compact ball during the telogen phase ; conversely , dermal sheath cells line the outside of the epithelial follicle from the bulge to the base . in development , hair follicle morphogenesis takes place during the late embryonic and early neonatal period ( millar , 2002 ) . postnatally , hair follicle neogenesis can be induced in adult mouse skin in response to transgenic or wound - induced epidermal activation of wnt/-catenin ( lo celso et al . , 2004 ; , 2005 ; ito et al . , 2007 ; lei et al . , k15 epscs produce canonical wnt ligands capable of activating hair follicle formation ( lei et al . , 2013 ) . associated with new hair follicles are dp ( silva - vargas et al . , 2005 ; ito et al . , 2007 ; 2013 ) , implying that cross - talk exists between wnt - activated epidermis and signals emanating from the dp . however , the mechanism underlying this cross - talk is largely unknown . cells sense the microenvironment via signal transduction pathways , culminating in altered gene expression ( jewer et al . , 2012 ) . candidate molecules secreted by the dp into the microenvironment that are in principle capable of mediating dermal / epidermal cross - talk are the so - called matricellular proteins . matricellular proteins are secreted extracellular matrix associated proteins that , through their ability to modify the activity of signaling molecules ( bornstein and sage , 2002 ) , are potential candidate molecules for mediating cellular cross - talk within niches . for example , the ccn family of matricellular proteins is increasingly being recognized as important in mediating pathological processes such as angiogenesis , oncogenesis , and fibrosis ( leask and abraham , 2006 ; jun and lau , 2011 ; perbal , 2013 ) . connective tissue growth factor ( ctgf , ccn2 ) , a member of the ccn family of secreted matricellular proteins , was discovered in 1991 during screening of a cdna expression library from human vein endothelial cells ( bradham et al . , 1991 ) . binding protein domain , a von willebrand factor type c domain , a thrombospondin type i repeat , and a c - terminal cysteine knot domain ( rachfal and brigstock , 2005 ; leask and abraham , 2006 ; jun and lau , 2011 ; perbal , 2013 ) . ccn2 is expressed by fibroblasts in response to fibrogenic agents such as transforming growth factor- ( tgf ; holmes et al . , 2001 ) . ccn2 directly promotes cell adhesion and indirectly mediates angiogenesis and fibrogenesis by modulating the activity of other molecules , notably platelet - derived growth factor and tgf ( mori et al . , 1999 ; rachfal and brigstock , 2005 ; shi - wen et al . , 2006 ) . we showed , using a mesenchymal cell specific knockout model , that ccn2 is required for fibrogenesis in skin ( liu et al . , 2011 ) for example , whether ccn2 expression by mesenchymal cells regulates hair follicle cycling is unknown . ccn2 is not readily detectable in adult mouse dermis unless it is induced , for example , in tissue repair and fibrosis ( kapoor et al . , 2008 ; liu et al . , previously , we used a tamoxifen - dependent cre recombinase under the control of a collagen type i promoter / enhancer to show that mice deleted for ccn2 in collagen type i producing cells were resistant to bleomycin - induced skin fibrosis ( liu et al . , 2011 ; zheng et al . , 2002 ) . however , the specific cells in which the activity of the collagen promoter / enhancer is active in uninjured adult skin , as well as the expression pattern of ccn2 within the hair follicle , are unclear . to address this issue , we generated col1a2-cre(er)-t ; rosa - stop - lacz mice . in these mice , lacz is not expressed in cells unless a stop codon is deleted via the expression of cre recombinase . postnatally , 3-wk - old mice were injected with corn oil or tamoxifen to activate cre recombinase in cells in which the col1a2 promoter is active . two weeks after tamoxifen injection , both ccn2 and lacz expression were surprisingly colocalized specifically to the outer root sheath ( ors ) and the dp ( figure 1a ; liu et al . , 2013 ) , indicating that in normal skin , ccn2 and the col1a2 promoter are coexpressed in the dp niche . costaining of tissue sections with anti - ccn2 antibody and an anti fibroblast surface protein 1 ( fsp1 ) antibody , which detects fibroblasts , revealed that ccn2 , but not fsp1 , was readily detected in the dp niche , whereas both ccn2 and fsp colocalized to the ors ( figure 1b ) , suggesting that fibroblasts were largely absent from the dp . ccn2 expression and col1a2 promoter activity colocalize to the dermal papillae ( dp ) , and ccn2 in dp was deleted in col1a2-cre(er)t/0 ; ccn2 mice after tamoxifen injection . ( a ) to identify cells in the skin that expressed the col1a2 promoter , col1a2-cre(er)t/0 ; rosa - stop - lacz/0 mice were generated . three - week - old mice were treated with tamoxifen as described in materials and methods . as a result , -galactosidase is expressed only in cells in which the col1a2 promoter is active at the time of injection . two weeks after cessation of tamoxifen injection , tissue sections were stained with anti - ccn2 and anti-galactosidase antibodies , as indicated . ( b , c ) as described in materials and methods , col1a2-cre(er)t/0 ; ccn2 mice were generated and treated with tamoxifen or corn oil to generate mice deleted ( k / k ) or not ( c / c ) for ccn2 in col1a2-expressing cells ( dp niche ) . ( b ) tissue sections of c / c mice undergoing hair follicle cycling were subjected to indirect immunofluorescence with anti - ccn2 and anti - fsp1 antibodies . ( c ) tissue sections of c / c and k / k mice undergoing hair follicle cycling were subjected to indirect immunofluorescence with anti - ccn2 and anti - ncam antibodies . note the early appearance of ncam staining , indicating dp activation , in k / k mice . n = 6 ; representative images are shown . to assess whether dp expression of ccn2 could affect hair follicle cycling , we generated col1a2-cre(er)-t/0 ; ccn2 mice . as described in materials and methods , 3-wk - old mice were injected with tamoxifen or corn oil to generate mice deleted ( k / k ) or not ( c / c ) for ccn2 in fibroblasts . we synchronized hair follicles by depilation at 1 wk after cessation of tamoxifen injection ( i.e. , the mice were in telogen ) . note the absence of ccn2 expression in the dp in ko mice ( figure 1c ) . note also that neural cell adhesion molecule ( ncam ) , a marker of hair follicle induction ( mller - rver et al . , 1998 ) , showed premature induction in anagen ii ( figure 1c ) . moreover , the length of the resting phase between cycles was reduced in ccn2 knockout mice ( figure 2a ) . to assess the effect of loss of ccn2 in fibroblasts on normal hair cycling , we generated an additional set of mice deleted ( k / k ) or not ( c / c ) for ccn2 in fibroblasts . instead , 6 mo after cessation of tamoxifen injection , skin was removed from mice and the number of hair follicles was assessed ; k / k mice had more hair follicles than wild - type ( c / c ) mice ( figure 2b ) . loss of ccn2 results in decreased time of telogen and increased number of hair follicles . as described in materials and methods , col1a2-cre(er)t/0 ; ccn2 mice were generated and treated with tamoxifen or corn oil to generate mice deleted ( k / k ) or not ( c / c ) for ccn2 in col1a2-expressing cells ( dp niche ) . ( a ) one week after cessation of tamoxifen injection , hair follicle cycles were synchronized by depilation . time to onset was calculated , duration of black skin was calculated as growth phase , and duration from disappearance of black skin to appearance of black skin was calculated as resting phase . ( b ) to test the effects of loss of ccn2 on normal hair cycling , 6 mo after cessation of tamoxifen injection , tissue sections were taken from mice deleted ( k / k ) or not ( c / c ) for ccn2 in col1a2-expressing cells ( dp niche ) and stained with hematoxylin and eosin , and the number of hair follicles / field was calculated for each of six mice . hence we assessed whether ccn2 could , in principle , alter the wnt signaling pathway in epithelial cells . wnt signals by binding to its receptor lrp6 ( angers and moon , 2009 ) . to begin to assess the potential effect of ccn2 on wnt signaling , we conducted an immunoprecipitation assay using rccn2 , rwnt3a , and rlrp6 . we found that rwnt3a could bind lrp6 , and this interaction was competed by increasing amounts of rccn2 ( figure 3a ) . these data are consistent with prior observations that rccn2 binds rlrp6 in an active site of the latter molecule ( mercurio et al . , 2004 ) . moreover , addition of rccn2 to cultured keratinocytes resulted in reduced steady - state levels of endogenous -catenin ( figure 3b ) . we injected 3-wk - old mice with tamoxifen or corn oil to delete ccn2 or not in cells in which the col1a2 promoter was active . two months after cessation of tamoxifen injection , loss of ccn2 resulted in an increase in -catenin accumulation and -catenin reporter activity in epithelial cells ( figure 4 , a and b ) . a subset of -catenin accumulation colocalized with k15 , suggesting that epscs showed increased -catenin steady - state levels ( figure 4c ) . rccn2 , rwnt3a , and rlrp-6 were combined in vitro and subjected to immunoprecipitation assays , as described in materials and methods . as described in materials and methods , a549 epithelial cells were exposed to different amounts of rccn2 . top , 0200 ng / ml of rccn2 incubated with cells for 24 h. bottom , 200 ng / ml of rccn2 incubated with cells for 012 h. ccn2 alters wnt - dependent signaling in vivo . ( as described in materials and methods , mice hemizygous for col1a2-cre(er)t and homozygous for ccn2 were generated . three - week - old mice were treated with tamoxifen or corn oil to generate mice deleted ( k / k ) or not ( c / c ) for ccn2 in col1a2-expressing cells ( i.e. , dp niche ) . two months after cessation of tamoxifen injection , tissue sections were stained with anti-catenin and anti - ccn2 antibodies . ( b ) fibroblast - specific ccn2 knockout mice show elevated topgal ( tcf / lef ) reporter activity . as described in materials and methods , mice hemizygous for col1a2-cre(er)t and for the topgal reporter that were also homozygous for ccn2 three - week - old mice were treated with tamoxifen or corn oil to generate mice deleted ( k / k ) or not ( c / c ) for ccn2 in col1a2-expressing cells ( i.e. , dp niche ) . two months after cessation of tamoxifen injection , whole - mount -galactosidase activity was stained as described in materials and methods . reporter activity in fibroblast - specific ccn2 knockout mice exists in k15 + eppcs . as described in materials and methods , mice hemizygous for col1a2-cre(er)t and for the topgal reporter that were also homozygous for ccn2 three - week - old mice were treated with tamoxifen or corn oil to generate mice deleted ( k / k ) or not ( c / c ) for ccn2 in col1a2-expressing cells ( i.e. , dp niche ) . two months after cessation of tamoxifen injection , tissue sections were stained with anti-gal and anti - k15 antibodies . as an independent confirmation that ccn2 expression by the dp and ors niche influences the wnt signaling pathway in target cells , we examined the effect of ccn2 on melanocytes , as wnt signaling coordinately promotes epithelial and melanocyte stem cell activation in hair regeneration ( rabbani et al . , 2011 ) . loss of ccn2 resulted in increased association of tyrosinase - related protein ( trp ) 2 , a melanocyte marker ( yavuzer and goding , 1994 ; rabbani et al . , 2011 ) , with the hair follicle that colocalized with -catenin reporter activity , suggesting that loss of ccn2 resulted in increased melanocyte differentiation ( figure 5 ) . collectively these data suggest that ccn2 controls the number of hair follicles within the skin . loss of ccn2 results in increased melanocyte differentiation . as described in materials and methods , mice hemizygous for col1a2-cre(er)t and for the topgal reporter that were also homozygous for ccn2 were generated and treated with tamoxifen or corn oil to generate mice deleted ( k / k ) or not ( c / c ) for ccn2 in col1a2-expressing cells . one week after cessation of tamoxifen injection , hair follicle cycles were synchronized by depilation . mice were killed at different stages of cycling , and tissue sections were stained with anti - trp2 and anti-gal antibodies and dapi to detect nuclei . cross - talk between epithelial and mesenchymal niches governs hair follicle cycling ; however , the underlying mechanism is unclear ( ohyama et al . , 2010 ) . it is likely that factors secreted from the mesenchymal niches govern the action of epithelial stem cells ; because of their abilities to modulate cell signaling , matricellular proteins are likely to play a significant role in this process ( bornstein and sage , 2002 ) . the ccn family of secreted matricellular proteins is emerging as a critical modulator of pathological processes such as cancer and fibrosis ( leask and abraham , 2006 ; jun and lau , 2011 ) , but the precise role of this family in normal tissue is unclear . here we uncover a heretofore unappreciated role for ccn2 in modulating hair follicle cycling ; ccn2 acts as a key regulator that controls niche signals and hence acts as an essential regulator of mesenchymal epithelial cross - talk that orchestrates the number of hair follicles . in particular , we show that loss of ccn2 expression postnatally affects normal hair cycling ; moreover , loss of ccn2 in collagen type i producing cells results in overall increases in hair follicle number concomitant with activation of -catenin reporter activity . our results are consistent with previous data identifying ccn2 mrna as being expressed in hair stem cells , associated with elevated hedgehog signaling ( tumbar et al . , 2004 ; rittie et al . , in addition to their role in modulating adhesion ( babic et al . , 1999 ; leask and abraham , 2006 ) , ccn proteins also bind extracellular ligands , modifying their activity ( perbal , 2013 ) . in this article these data suggest that ccn2 , by blocking the ability of wnt to bind its receptor , normally suppresses hair follicle cycling . in the future , ccn2 agonists / antagonists might be used to alter hair stem cell function and hence hair regeneration . for example , ccn3 , which is known to antagonize ccn2 activity ( riser et al . , 2010 ; perbal , 2013 ) , might be used to promote hair growth . mice deleted or not for ccn2 in collagen type i expressing cells were generated as previously described ( liu et al . , 2011 ) . briefly , mice ( c57bl/6 ) hemizygous for col1a2-cre ( er)-t and homozygous for ccn2 mice were generated by crossing . three - week - old mice were injected with corn oil or tamoxifen to generate mice deleted or not for ccn2 in fibroblasts . when indicated , mice were generated that were also hemizygous for topgal reporter ( c57bl/6 ) mice , which express -galactosidase as a reporter in the presence of the lymphoid enhancer binding factor 1/transcription factor 3mediated signaling pathway and activated -catenin ( jackson labs , bar harbor , me ) . when indicated , depilation of mid dorsal hair follicles was achieved on anaesthetized mice 1 wk after cessation of tamoxifen injection to provide a proliferative stimulus and to synchronize a population of anagen hair follicles . all experiments were approved by the appropriate regulatory committee of the university of western ontario . to identify cells expressing the col1a2 promoter , col1a2-cre ( er)-t mice ( zheng et al . , 2002 ) were crossed with rosa - stop - lacz ( c57bl/6 ) mice ( jackson labs ) in which the loxp - flanked dna stop sequence preventing expression of the downstream lacz gene was used . competition binding between rccn2 , rwnt3a , and receptor rlrp-6 was detected by an immunoprecipitation assay . mouse rlrp-6 with histidine ( his ) tag ( r&d systems , minneapolis , mn ; 0.5 g in 50 l of 150 mm nacl , 50 mm tris - hcl , ph 7.5 , 0.1% triton x-100 , and proteinase inhibitors ) was preincubated with full - length rccn2 ( 1 g ; prospec , east brunswick , nj ) at 4c for 2 h. then rwnt3a ( 0.4 g ; sigma , st . after incubation , nickel - nitriloacetic acid agarose ( qiagen , toronto , on , canada ) was added to the mixture and incubated on ice for 2 h. the agarose beads were pelleted by centrifugation and washed six times over 30 min with incubation buffer . proteins were subjected to sds page and immunoblotted with the following antibodies according to the manufacturer 's instructions : anti - his tag ( 1:2000 for lrp-6 ; sigma ) , anti - wnt3a ( 1:1000 ; santa cruz biotechnology , santa cruz , ca ) , and anti - flag ( 1:2000 for ccn2 ; sigma ) . the ecl+ detection technique ( amersham ) the effect of rccn2 on -catenin expression in a549 epithelial cells ( american type culture collection ) was assessed by culturing cells in dmem ( invitrogen , burlington , on , canada ) containing 10% fbs ( invitrogen ) in six - well plates . at 70% confluence , cells were starved overnight in dmem with 0.5% fetal bovine serum and then stimulated with rccn2 ( prospec ) at different concentration for the durations indicated . the cells were then washed two times with phosphate - buffered saline ( pbs ) and lysed in ripa buffer containing cocktail proteinase inhibitors ( roche ) . cell lysates were subjected to sds page and immunoblotted with anti-catenin antibody ( 1:5000 ; sigma ) . paraffin - embedded tissue sections ( 0.5 m ) were cut using a microtome ( leica , richmond hill , canada ) , collected on superfrost plus slides ( thermo fisher , ottawa , canada ) , dewaxed in xylene , and rehydrated by immersion in descending concentrations of alcohol . tissue sections were blocked by incubation with 5% donkey serum for 1 h and then incubated with primary antibodies overnight at 4c under humidified conditions . primary antibodies used were as follows : goat anti - ccn2 ( 1:200 dilution ; santa cruz biotechnology ) , mouse anti-galactosidase ( 1:100 dilution ; abcam ) , anti - k15 ( 1:200 dilution ; neomarker , thermo fisher , ottawa , on , canada ) , anti - trp1 ( 1:200 dilution ; santa cruz biotechnology ) , and anti - fsp1 ( 1:100 dilution ; abcam , cambridge , uk ) . after primary antibody incubation , sections were washed with pbs and incubated with appropriate fluorescent secondary antibodies ( jackson immunoresearch , west grove , pa ) for 1 h at room temperature . sections were washed with pbs , mounted using 4,6-diamidino-2-phenylindole ( dapi ) , and imaged using fluorescence microscopy and northern eclipse software ( empix , mississauga , canada ) . for whole - mount -galactosidase staining , skin samples were fixed in 0.2% glutaraldehyde/1% formaldehyde/0.02% nonidet p-40 in pbs overnight at 4c . after washing with pbs for 3 10 min at room temperature , tissues were incubated in x - gal staining solution ( 5 mm k3fe(cn)6 , 5 mm k4fe(cn)6 , 2 mm mgcl2 , 1 mg / ml x - gal in pbs ) overnight at room temperature on a rocking platform . tissues were kept in pbs for 2 d to allow for the stain to develop . the staining was then stopped by 4% paraformaldehyde , embedded in paraffin , and subsequently sectioned for histology . the sections were dewaxed in xylene , rehydrated by immersion in descending concentrations of alcohol , and costained with eosin . mice deleted or not for ccn2 in collagen type i expressing cells were generated as previously described ( liu et al . , 2011 ) . briefly , mice ( c57bl/6 ) hemizygous for col1a2-cre ( er)-t and homozygous for ccn2 mice were generated by crossing . three - week - old mice were injected with corn oil or tamoxifen to generate mice deleted or not for ccn2 in fibroblasts . when indicated , mice were generated that were also hemizygous for topgal reporter ( c57bl/6 ) mice , which express -galactosidase as a reporter in the presence of the lymphoid enhancer binding factor 1/transcription factor 3mediated signaling pathway and activated -catenin ( jackson labs , bar harbor , me ) . when indicated , depilation of mid dorsal hair follicles was achieved on anaesthetized mice 1 wk after cessation of tamoxifen injection to provide a proliferative stimulus and to synchronize a population of anagen hair follicles . all experiments were approved by the appropriate regulatory committee of the university of western ontario . to identify cells expressing the col1a2 promoter , col1a2-cre ( er)-t mice ( zheng et al . , 2002 ) were crossed with rosa - stop - lacz ( c57bl/6 ) mice ( jackson labs ) in which the loxp - flanked dna stop sequence preventing expression of the downstream lacz gene was used . competition binding between rccn2 , rwnt3a , and receptor rlrp-6 was detected by an immunoprecipitation assay . mouse rlrp-6 with histidine ( his ) tag ( r&d systems , minneapolis , mn ; 0.5 g in 50 l of 150 mm nacl , 50 mm tris - hcl , ph 7.5 , 0.1% triton x-100 , and proteinase inhibitors ) was preincubated with full - length rccn2 ( 1 g ; prospec , east brunswick , nj ) at 4c for 2 h. then rwnt3a ( 0.4 g ; sigma , st . after incubation , nickel - nitriloacetic acid agarose ( qiagen , toronto , on , canada ) was added to the mixture and incubated on ice for 2 h. the agarose beads were pelleted by centrifugation and washed six times over 30 min with incubation buffer . proteins were subjected to sds page and immunoblotted with the following antibodies according to the manufacturer 's instructions : anti - his tag ( 1:2000 for lrp-6 ; sigma ) , anti - wnt3a ( 1:1000 ; santa cruz biotechnology , santa cruz , ca ) , and anti - flag ( 1:2000 for ccn2 ; sigma ) . the ecl+ detection technique ( amersham ) the effect of rccn2 on -catenin expression in a549 epithelial cells ( american type culture collection ) was assessed by culturing cells in dmem ( invitrogen , burlington , on , canada ) containing 10% fbs ( invitrogen ) in six - well plates . at 70% confluence , cells were starved overnight in dmem with 0.5% fetal bovine serum and then stimulated with rccn2 ( prospec ) at different concentration for the durations indicated . the cells were then washed two times with phosphate - buffered saline ( pbs ) and lysed in ripa buffer containing cocktail proteinase inhibitors ( roche ) . cell lysates were subjected to sds page and immunoblotted with anti-catenin antibody ( 1:5000 ; sigma ) . paraffin - embedded tissue sections ( 0.5 m ) were cut using a microtome ( leica , richmond hill , canada ) , collected on superfrost plus slides ( thermo fisher , ottawa , canada ) , dewaxed in xylene , and rehydrated by immersion in descending concentrations of alcohol . tissue sections were blocked by incubation with 5% donkey serum for 1 h and then incubated with primary antibodies overnight at 4c under humidified conditions . primary antibodies used were as follows : goat anti - ccn2 ( 1:200 dilution ; santa cruz biotechnology ) , mouse anti-galactosidase ( 1:100 dilution ; abcam ) , anti - k15 ( 1:200 dilution ; neomarker , thermo fisher , ottawa , on , canada ) , anti - trp1 ( 1:200 dilution ; santa cruz biotechnology ) , and anti - fsp1 ( 1:100 dilution ; abcam , cambridge , uk ) . after primary antibody incubation , sections were washed with pbs and incubated with appropriate fluorescent secondary antibodies ( jackson immunoresearch , west grove , pa ) for 1 h at room temperature . sections were washed with pbs , mounted using 4,6-diamidino-2-phenylindole ( dapi ) , and imaged using fluorescence microscopy and northern eclipse software ( empix , mississauga , canada ) . for whole - mount -galactosidase staining , skin samples were fixed in 0.2% glutaraldehyde/1% formaldehyde/0.02% nonidet p-40 in pbs overnight at 4c . after washing with pbs for 3 10 min at room temperature , tissues were incubated in x - gal staining solution ( 5 mm k3fe(cn)6 , 5 mm k4fe(cn)6 , 2 mm mgcl2 , 1 mg / ml x - gal in pbs ) overnight at room temperature on a rocking platform . tissues were kept in pbs for 2 d to allow for the stain to develop . the staining was then stopped by 4% paraformaldehyde , embedded in paraffin , and subsequently sectioned for histology . the sections were dewaxed in xylene , rehydrated by immersion in descending concentrations of alcohol , and costained with eosin . Output:	mesenchymal cells play a role in controlling the number of hair follicles . however , the precise molecules involved are unclear . absence in mesenchymal cells of the expression of the secreted matricellular protein ctgf / ccn2 results in an increased number of hair follicles , concomitant with increased -catenin activity .
PubmedSumm118896	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: ovarian cancer is the 5th leading cause of death among malignancies and accounting for approximately 240,000 cases and 150,000 deaths in 2012 worldwide . nearly 2/3 of cases are diagnosed in its advanced stages or unstaged and just 30% for 5-year survival rate for these patients . this emphasizes the need to focus on identifying risk factors , in order to reduce the risk of ovarian cancer . the associations among dietary flavonoids , flavonoid subclasses , bilateral salpingectomy , depression and anxiety , dietary fat and fatty acid , overweight , or obesity and the incidence of ovarian cancer have been evaluated in previous meta - analyses . however , several other factors associations with the risk of ovarian cancer are not precisely understood and remain controversial . diabetes mellitus ( dm ) is a growing global pandemic affecting approximately 3.0% to 4.0% of adults worldwide . systematic reviews and meta - analyses have already evaluated the risk of cancer incidence at different sites . a previous study indicated that women with dm have a moderately increased risk of developing ovarian cancer . however , traditional case control studies were included in the previous study , which are less strong than cohort studies , and the findings of stratified analyses were affected by differences in study design . several prospective cohort studies that explored the relationship between dm and ovarian cancer risk have already been published . several studies suggested that dm is associated with an elevated risk of ovarian cancer , whereas other studies showed no evidence for this association . clarifying any potential correlation between dm and ovarian cancer , which has not been definitively established , is particularly important in the general population . we therefore attempted a comprehensive examination of the available cohort studies to determine the association between dm and the incidence of ovarian cancer . this study was conducted and reported according to the meta - analysis of observational studies in epidemiology protocol . any prospective observational study that examined the relationship between dm and ovarian cancer was eligible for inclusion in this review . the included articles were restricted to those published in english ; however , there was no restriction on publication status ( published , in press , or in progress ) . electronic databases including pubmed , embase , and the cochrane library were systematically searched by using the combination of the search terms ( diabetes or dm or glucose ) and ( cancer , carcinoma , neoplasm , and tumor ) and ovarian , with the deadline being september 2016 . to identify unpublished studies or collect updated information in some of the included studies that could provide useful data , we contacted the authors , reviewed abstracts and presentations of recent major meetings , and searched for ongoing studies that were registered as completed but not yet published . manual searches of reference lists from all the relevant articles were conducted to identify additional potential eligible studies . all analyses were based on previous published studies , thus no ethical approval and patient consent are required . after the literature search , the selected studies were independently reviewed by 2 of the authors , and a group discussion settled any inconsistencies until a consensus was reached . a study was eligible for inclusion if the following criteria were met : the study had a prospective cohort design ; the study investigated the association between dm and the risk of ovarian cancer ; and the study reported an effect estimate ( risk ratio [ rr ] , hazard ratio , or odds ratio ) and 95% confidence intervals ( cis ) for comparisons of dm and non - dm participants . we excluded all retrospective case control studies owing to various confounding factors that could bias the results . the data extraction and quality assessment processes were conducted independently by 2 of the authors . data were extracted on the basis of the first author , publication year , country , sample size , mean age at baseline , body mass index ( bmi ) , number of ovarian cancer cases , follow - up duration , and adjusted factors . for studies that reported several multivariable adjusted effect estimates , we selected the maximally adjusted estimates for potential confounders . this scale was categorized into 3 groups of items : selection ( representativeness of the exposed cohort ; selection of the nonexposed cohort ; ascertainment of dm ; demonstration that ovarian cancer was not present at start of study ; 4 points ) , comparability ( comparability on the basis of the design or analysis ; 2 points ) , and outcome ( assessment of outcome ; adequate follow - up duration ; adequate follow - up rate ; 3 points ) , with a total of 9 points . in this review , studies with a total of score of 8 or 9 were considered to be of high quality . we examined the relationship between dm and the risk of ovarian cancer on the basis of the effect estimate ( rr , hazard ratio , or odds ratio ) and its 95% ci published in each study . the random effects model was used for data pooling of dm versus non - dm participants . i values of < 25% , 25% to 50% , 50% to 75% , and > 75% were considered to indicate no , low , moderate , and high heterogeneity , respectively . p < .05 or i > 50% was deemed to denote a significant heterogeneity . subgroup analyses were conducted for ovarian cancer incidence on the basis of publication year , country , mean age , follow - up duration , adjusted bmi , adjusted smoking status , and study quality . sensitivity analysis was conducted by removing a single study from the overall analysis to evaluate the impact of an individual study . visual inspections of funnel plots for ovarian cancer were conducted . the egger and begg tests were employed to statistically assess publication bias for ovarian cancer . all reported p values were 2-sided , and p values < .05 were considered statistically significant for all included studies . statistical analyses were performed by using stata software ( version 10.0 ; stata corporation , college station , tx ) . this study was conducted and reported according to the meta - analysis of observational studies in epidemiology protocol . any prospective observational study that examined the relationship between dm and ovarian cancer was eligible for inclusion in this review . the included articles were restricted to those published in english ; however , there was no restriction on publication status ( published , in press , or in progress ) . electronic databases including pubmed , embase , and the cochrane library were systematically searched by using the combination of the search terms ( diabetes or dm or glucose ) and ( cancer , carcinoma , neoplasm , and tumor ) and ovarian , with the deadline being september 2016 . to identify unpublished studies or collect updated information in some of the included studies that could provide useful data , we contacted the authors , reviewed abstracts and presentations of recent major meetings , and searched for ongoing studies that were registered as completed but not yet published . manual searches of reference lists from all the relevant articles were conducted to identify additional potential eligible studies . all analyses were based on previous published studies , thus no ethical approval and patient consent are required . after the literature search , the selected studies were independently reviewed by 2 of the authors , and a group discussion settled any inconsistencies until a consensus was reached . a study was eligible for inclusion if the following criteria were met : the study had a prospective cohort design ; the study investigated the association between dm and the risk of ovarian cancer ; and the study reported an effect estimate ( risk ratio [ rr ] , hazard ratio , or odds ratio ) and 95% confidence intervals ( cis ) for comparisons of dm and non - dm participants . we excluded all retrospective case control studies owing to various confounding factors that could bias the results . the data extraction and quality assessment processes were conducted independently by 2 of the authors . any discrepancy was resolved through a discussion or by consulting the corresponding author . data were extracted on the basis of the first author , publication year , country , sample size , mean age at baseline , body mass index ( bmi ) , number of ovarian cancer cases , follow - up duration , and adjusted factors . for studies that reported several multivariable adjusted effect estimates , we selected the maximally adjusted estimates for potential confounders . this scale was categorized into 3 groups of items : selection ( representativeness of the exposed cohort ; selection of the nonexposed cohort ; ascertainment of dm ; demonstration that ovarian cancer was not present at start of study ; 4 points ) , comparability ( comparability on the basis of the design or analysis ; 2 points ) , and outcome ( assessment of outcome ; adequate follow - up duration ; adequate follow - up rate ; 3 points ) , with a total of 9 points . in this review , studies with a total of score of 8 or 9 were considered to be of high quality . we examined the relationship between dm and the risk of ovarian cancer on the basis of the effect estimate ( rr , hazard ratio , or odds ratio ) and its 95% ci published in each study . the random effects model was used for data pooling of dm versus non - dm participants . i values of < 25% , 25% to 50% , 50% to 75% , and > 75% were considered to indicate no , low , moderate , and high heterogeneity , respectively . p < .05 or i > 50% was deemed to denote a significant heterogeneity . subgroup analyses were conducted for ovarian cancer incidence on the basis of publication year , country , mean age , follow - up duration , adjusted bmi , adjusted smoking status , and study quality . sensitivity analysis was conducted by removing a single study from the overall analysis to evaluate the impact of an individual study . the egger and begg tests were employed to statistically assess publication bias for ovarian cancer . all reported p values were 2-sided , and p values < .05 were considered statistically significant for all included studies . statistical analyses were performed by using stata software ( version 10.0 ; stata corporation , college station , tx ) . among the 2042 studies that were identified through searching pubmed , embase , and the cochrane library , 1984 duplicates ( n = 1152 ) and irrelevant ( n = 832 ) records were first excluded . 9 studies with a case control design , 13 studies showing insufficient data , and 23 epidemiology studies on other risk factors were excluded . of the 13 included studies , 5 were conducted in europe , 2 were conducted in the united states or canada , and the remaining 6 were conducted in asia . the number of participants ranged from 11,686 to 1,152,122 , with a total of 3,708,313 women . the mean age of participants ranged from 44.0 to 62.6 years , and the follow - up duration ranged from 3.5 to 15.0 years . the nos score of the included studies ranged from 6 to 8 , with 5 studies being of high quality and the remaining 8 studies being of low quality ( table 1 ) . overall , 5 studies had a score of 8 , 6 studies had a score of 7 , and the remaining 2 studies had a score of 6 . the summary result is shown in fig . 2 , and we noted that women with dm had a higher risk of developing ovarian cancer when compared with non - dm participants ( rr : 1.19 ; 95% ci : 1.061.34 ; p = .004 ; fig . 2 ) , and a significant heterogeneity was observed ( i = 43.8% ; p = .040 ) . as a result , a sensitivity analysis was conducted , and after each study was sequentially excluded from the pooled analysis , the conclusion was not affected by the exclusion of any specific study ( table 2 ) . q - test for the analysis showed a value of p < .05 for ovarian cancer . therefore , we conducted subgroup analyses to minimize the heterogeneity among the included studies and evaluate this relationship in specific subsets ( table 3 ) . overall , we noted that women with dm had an elevated risk of ovarian cancer in studies published after 2010 ( rr : 1.18 ; 95% ci : 1.041.34 ; p = .010 ) , studies not conducted in europe or the united states ( rr : 1.26 ; 95% ci : 1.061.50 ; p = .008 ) , studies that did not adjust for bmi ( rr : 1.15 ; 95% ci : 1.041.27 ; p = .007 ) or smoking status ( rr : 1.20 ; 95% ci : 1.051.35 ; p = .005 ) , and studies with lower nos scores ( rr : 1.22 ; 95% ci : 1.071.38 ; p = .003 ) . no other significant difference was observed between the presence and absence of dm for ovarian cancer based on predefined factors . a review of the funnel plots could not rule out the potential for publication bias for ovarian cancer ( fig . the egger and begg test results showed no evidence of publication bias ( p value for egger = .378 ; p value for begg = .381 ) . the purpose of the present meta - analysis was to determine the correlates of dm and the incidence of ovarian cancer . this result will help in better defining the risk factors of ovarian cancer , and could help physicians in evaluating the risk score of the general population . the impact factor for the incidence of ovarian cancer has already been reported in previous meta - analyses . hua et al reported that consumption of dietary flavonoids and their subtypes ( isoflavones , flavonols ) has a protective effect against ovarian cancer ( reduces the risk of ovarian cancer ) ; however , flavone consumption had no such effect . yoon et al found that removal of the fallopian tubes is an effective approach to protect against ovarian cancer risk in the general population . liu et al indicated that a high body weight might have a harmful impact on the risk of ovarian cancer , especially for premenopausal women with severe obesity . chodick et al conducted a retrospective cohort study and found that dm increased the ovarian cancer risk by 139% after an average of 8 years follow - up . dankner et al indicated that dm posed an increased risk of ovarian cancer , with the rrs being particularly elevated during the first year after the diabetes diagnosis ; however , their study had a shorter follow - up duration of between 1 and 2 years . the increased risk of ovarian cancer could be due to perturbations in insulin , insulin - like growth factors , gonadotropin , and steroid hormone metabolism , which could affect cell proliferation . the subgroup analyses suggested that dm had a harmful impact on ovarian cancer in studies not conducted in europe or the united states . the reason for this could be that the prevalence of dm was higher in asia , and the diagnosis of dm took a longer time than in western countries . in studies that did not adjust for bmi or smoking status , a significant difference was found between the presence and absence of dm for ovarian cancer , which might have biased the true correlates of dm and ovarian cancer . progesterone and leptin may be potential endocrine mediators of the risk of ovarian cancer , and obesity was associated with the levels of insulin , androgens , and free insulin - like growth factor - i , which play an important role in the risk of ovarian cancer . faber et al suggested that current smokers had an increased risk of developing invasive mucinous and borderline mucinous ovarian tumors , and former smokers also have an increased risk of developing borderline serous ovarian tumors . in addition , we noted dm was associated with higher incidence of ovarian cancer if the study published after 2010 . the reason for this could be mostly included studies published after 2010 ( 9/13 ) . the relationship between dm and ovarian cancer in study published before 2010 was available in few studies , and the follow - up , number of participants were lower than study published after 2010 , which always acquired broad cis , that is , no statistically significant difference . in this study , we intended to conduct a stratified analysis based on these factors ; however , data in each subset were not available . in addition , for several other subpopulations , the findings might be unstable owing to the smaller number of included studies . first , a language bias may exist in the selection of studies published only in english . second , the types of dm and ovarian cancer were not available , which could have introduced confounder biases . third , the heterogeneity among included studies was relatively high , and the heterogeneity in subgroup analysis was also higher . . finally , the adjusted models , which might play an important role in the development of ovarian cancer , differed among the included studies . the present meta - analysis demonstrated that women with dm had an increased risk of developing ovarian cancer , especially among asians . to lower the risk of ovarian cancer , any potential risk factors need to be investigated , in order to allow early diagnosis and treatment . Output:	abstractepidemiologic studies have suggested that diabetes mellitus ( dm ) might be associated with risk of ovarian cancer ; however , the results have been inconsistent . the aim of this study was to determine the relationship between dm and the incidence of ovarian cancer on the basis of cohort studies.relevant studies from pubmed , embase , and the cochrane library until september 2016 were collected . the summary risk ratio ( rr ) was used as the effect measure in a random effects model . sensitivity analysis , subgroup analysis , and calculation of publication bias were conducted.thirteen articles including 14 cohorts comprising a total of 3708 , 313 women and reporting 5534 cases of ovarian cancer were included . the summary rr suggested that patients with dm had a higher risk of ovarian cancer than patients without dm ( rr : 1.19 ; 95% confidence interval : 1.061.34 ; p = .004 ) , and no evidence of publication bias was found . the subgroup analysis indicated a higher incidence of ovarian cancer in patients with dm in studies published after 2010 , studies not conducted in europe or the united states , studies that did not adjust for body mass index or smoking status , and studies with lower newcastle ottawa scale scores.the present findings indicated that dm is a risk factor for ovarian cancer , and future large - scale epidemiologic studies should be performed to evaluate this relation in specific populations .
PubmedSumm118897	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: a 41-year - old systemically healthy female patient presented with the chief complaint of missing teeth in the left upper posterior region for past 7 months . patient gave a dental history of implant placement in relation to 24 , 44 , and 47 1 year back . patient had undergone endodontic therapy in relation to 11 , 21 , 15 , 16 , and 17 with postendodontic restoration . a tooth supported fixed partially denture in relation to 34.35 and 36 and an implant supported fixed partial denture in relation to 44 , 45 , 46 , and 47 region . digital orthopantomogram ( opg ) revealed a residual bone height of < 2 mm in relation to 26.27 and around 4 mm in 25 region with a pneumatized sinus and horizontal bone loss on the mesial aspect of implant in 24 region . treatment plan of lateral wall osteotomy approach for sinus augmentation associated with simultaneous implant placement in 25 , 26 , and 27 region was decided upon . in spite of the literature data insisting on the minimum of 4 mm alveolar bone height for simultaneous implant placement during sinus augmentation procedures the decision of simultaneous implant placement was still considered due to the fact that implants placed creates a tenting effect resulting in excellent space maintenance for optimal regeneration . moreover such approach greatly reduces over all treatment duration and multiple surgical appointments . considering the bone loss in 24 region a laser debridement was also planned followed by placement of splinted metal ceramic crowns involving 4 implants including implant in 24 region . the risk of perforating the sinus membrane and the possible complications was also explained and written informed consent was obtained . the surgical site was anaesthetized by local infiltration with 2% lignocaine hydrochloride ( 1:200000 adrenalin ) . two vertical releasing incisions one on the distal line angle of 24 and the other on the distal most aspect of the ridge with a para crestal incision joining both these vertical releasing incisions was given [ figure 1a and 1b ] . a mucoperiosteal flap was elevated exposing the lateral wall of the maxillary sinus [ figure 1c ] . ( a ) preoperative intraoral view , ( b ) placement of para crestal and vertical releasing incisions , ( c ) flap elevated exposing the lateral bony wall , ( d ) preparation of bony window using a round end piezo tip a bony window was prepared [ figure 1d ] and was infractured , followed by the elevation of the schneiderian membrane using the sinus elevation tips . during sinus membrane elevation a class iia type perforation occurred [ figure 2a ] , following complete elevation of the sinus membrane an implant osteotomy was performed in 25 , 26 and 27 region [ figure 2b ] . ( a ) infracture of bony window , perforation of sinus membrane encountered during membrane elevation , ( b ) implant osteotomy sites prepared in 25 , 26 and 27 , ( c ) type i collagen membrane ( biomend extend ) placed to repair the perforated sinus membrane , ( d ) sinus cavity partially packed with deproteinized bovine bone ( bio - oss ) before placing the implants the perforation of the schneiderian membrane was managed by adapting a contoured guided bone regeneration ( gbr ) type i collagen membrane ( biomend extend - zimmer dental , 1900 aston avenue , carlsbad , ca 92008 - 7308 usa , lot no . : 1094148 ) in such a way that the perforated membrane was completely shielded from the elevated sinus cavity [ figure 2c ] . the sinus space was partially packed with deproteinized bovine bone ( bio - oss - geistlich biomaterials batch no . 080307 ) hydrated with blood [ figure 2d ] followed by the placement of three wide platform tapered self - threaded titanium implants ( hi - tec life care israel for life care devices private limited , 202 jesia building , jame jamshed road , dadar east , mumbai - 14 lot no : 030610,08097,16108 ) [ figure 3a ] . the residual spaces around the implants were further packed with bio - oss graft [ figure 3b ] . a type 1 collagen gbr membrane ( biomend extend ) was contoured and adapted to cover the bony window and tucked under the palatal flap [ figure 3c ] . the reflected flap was approximated with 4 - 0 vicryl ( ethicon , inc . , johnson and johnson , somerville , nj , usa ) using simple interrupted sutures [ figure 3d ] . ( a ) implant placed in prepared osteotomy sites , ( b ) residual sinus cavity filled with bio oss , ( c ) placement of collagen membrane ( bio mend extend ) to cover the implants and access window , ( d ) flap approximated using 4 - 0 vicryl suture material the patient was placed on amoxicillin / clavulinic acid 625 mgs 2 tablets / day for 5 days , ibuprofen / paracetomol 3 tablets / day for 5 days and fexofenadine chloride 60 mg plus pseudoephedrine chloride 120 mg 1 tablet every 12 h , for 7 days ( decongestant ) . patient was advised to rinse with chlorhexidine gluconate 0.2% mouth wash twice daily for the following 4 weeks . patient was reviewed the next day and after 4 weeks with the postsurgical healing being uneventful at this junction laser debridement for the aligning implant in 24 region was performed . patient was placed on periodic recall every 2 months until the 8 month during which a digital opg and computed tomography was taken . the radiographs showed the position of implant and dense bone fill in the sinus cavity [ figure 4a d ] . ( a ) fully functional metal ceramic prosthesis , ( b ) computed tomography shows the position of implants , ( c ) preoperative radiograph shows ridge deficiency , ( d ) 8 months postoperative radiograph shows the augmented site with implants during the second stage the implant recovery was done with laser and healing caps were placed and left in place for 4 weeks . 4 weeks following healing cap placement the prosthetic abutment was screwed in with a 40 ncm torque . the metal ceramic crown on 24 implant was retrieved and a silicone impression was taken involving implant abutments in 24 , 25 , 26 and 27 region . following metal and ceramic try in , a metal ceramic prosthesis ( 5 units considering the mesiodistal space available ) was cemented and patient was reviewed after a week during which the patient was comfortable and the prosthesis was fully functional . using a round end piezo tip a bony window was prepared [ figure 1d ] and was infractured , followed by the elevation of the schneiderian membrane using the sinus elevation tips . during sinus membrane elevation a class iia type perforation occurred [ figure 2a ] , following complete elevation of the sinus membrane an implant osteotomy was performed in 25 , 26 and 27 region [ figure 2b ] . ( a ) infracture of bony window , perforation of sinus membrane encountered during membrane elevation , ( b ) implant osteotomy sites prepared in 25 , 26 and 27 , ( c ) type i collagen membrane ( biomend extend ) placed to repair the perforated sinus membrane , ( d ) sinus cavity partially packed with deproteinized bovine bone ( bio - oss ) before placing the implants the perforation of the schneiderian membrane was managed by adapting a contoured guided bone regeneration ( gbr ) type i collagen membrane ( biomend extend - zimmer dental , 1900 aston avenue , carlsbad , ca 92008 - 7308 usa , lot no . : 1094148 ) in such a way that the perforated membrane was completely shielded from the elevated sinus cavity [ figure 2c ] . the sinus space was partially packed with deproteinized bovine bone ( bio - oss - geistlich biomaterials batch no . 080307 ) hydrated with blood [ figure 2d ] followed by the placement of three wide platform tapered self - threaded titanium implants ( hi - tec life care israel for life care devices private limited , 202 jesia building , jame jamshed road , dadar east , mumbai - 14 lot no : 030610,08097,16108 ) [ figure 3a ] . the residual spaces around the implants were further packed with bio - oss graft [ figure 3b ] . a type 1 collagen gbr membrane ( biomend extend ) was contoured and adapted to cover the bony window and tucked under the palatal flap [ figure 3c ] . the reflected flap was approximated with 4 - 0 vicryl ( ethicon , inc . , johnson and johnson , somerville , nj , usa ) using simple interrupted sutures [ figure 3d ] . ( a ) implant placed in prepared osteotomy sites , ( b ) residual sinus cavity filled with bio oss , ( c ) placement of collagen membrane ( bio mend extend ) to cover the implants and access window , ( d ) flap approximated using 4 - 0 vicryl suture material the patient was placed on amoxicillin / clavulinic acid 625 mgs 2 tablets / day for 5 days , ibuprofen / paracetomol 3 tablets / day for 5 days and fexofenadine chloride 60 mg plus pseudoephedrine chloride 120 mg 1 tablet every 12 h , for 7 days ( decongestant ) . patient was advised to rinse with chlorhexidine gluconate 0.2% mouth wash twice daily for the following 4 weeks . patient was reviewed the next day and after 4 weeks with the postsurgical healing being uneventful at this junction laser debridement for the aligning implant in 24 region was performed . patient was placed on periodic recall every 2 months until the 8 month during which a digital opg and computed tomography was taken . the radiographs showed the position of implant and dense bone fill in the sinus cavity [ figure 4a d ] . ( a ) fully functional metal ceramic prosthesis , ( b ) computed tomography shows the position of implants , ( c ) preoperative radiograph shows ridge deficiency , ( d ) 8 months postoperative radiograph shows the augmented site with implants during the second stage the implant recovery was done with laser and healing caps were placed and left in place for 4 weeks . 4 weeks following healing cap placement the prosthetic abutment was screwed in with a 40 ncm torque . the metal ceramic crown on 24 implant was retrieved and a silicone impression was taken involving implant abutments in 24 , 25 , 26 and 27 region . following metal and ceramic try in , a metal ceramic prosthesis ( 5 units considering the mesiodistal space available ) was cemented and patient was reviewed after a week during which the patient was comfortable and the prosthesis was fully functional . maxillary sinus augmentation is commonly undertaken to enhance otherwise inadequate bone dimension for placement of dental implants in the posterior maxilla . the most important factor is to keep the schneiderian membrane intact during sinus augmentation so that once lifted , it can become the recipient site for the bone graft and it stabilizes the graft during the healing period , constituting an important barrier for the protection and defense of the sinus cavity . complications reported during sinus augmentation surgery are excessive bleeding during surgery , implant migration , hematoma , injury of the infraorbital neurovascular bundle and adjacent tooth sensitivity of which the most significant complication is membrane perforation which has a negative impact on graft remodeling . though piezo surgical techniques are frequently employed in sinus augmentation procedures for atraumatic osteotomy and to minimize membrane perforation , incidence of schneiderian membrane tear various techniques used for the treatment of membrane tear are circumelevation technique , loma linda pouch technique and the perforated membrane can be managed by using tissue fibrin glue , suturing or by covering them with a resorbable barrier membrane in case of small perforation ( < 5 mm ) , if the perforation is > 5 mm larger barrier membranes , lamellar bone plates or suturing either alone or combination with fibrin glue can be advocated . in the present case report the type of perforation was a class ii a and the size of perforation was larger than 3 mm so it was managed using a resorbable membrane . various graft materials such as autogenous , allogenous , xenograft and alloplastic materials have improved the results of sinus augmentation techniques and made them more predictable . deproteinized bovine bone ( bio - oss ) as used in the present study have shown to be favorable due to its optimal resorption period , commercial availability , higher survival rate of implants and excellent handling characteristics . simultaneous implant placement during external sinus augmentation requires a minimum of 4 mm of remaining alveolar bone for minimal initial stability and preventing implant migration during regeneration . in the present case report , implants were placed in the sites with the residual alveolar bone of lesser than 2 mm considering various advantages such as fewer surgical procedures , reduced overall treatment duration , less morbidity , less financial expense and less patient anxiety . added advantage of the implant placed in the residual alveolar bone of lesser than 2 mm is the tenting effect of the implant on the repaired sinus membrane acting as a space maintainer . in the present case report , implants were placed simultaneously during sinus augmentation procedure in spite of < 2 mm of bone height available in 26 and 27 region and during the sinus augmentation membrane perforation occurred , which was carefully managed , postoperative healing showed optimal bone fill in the sinus region and successful ossiointegration in the implant sites . external sinus augmentation with simultaneous implant placement is a viable option even in areas with residual bone height of < 4 mm as this approach reduces overall treatment duration and the stress of multiple surgical procedures for the patients . Output:	dental implant associated rehabilitation of the posterior maxilla poses unique challenge owing to the presence of pneumatized sinuses and atrophied alveolar bone . sinus augmentation procedure to manage expanded sinuses frequently results in membrane tear resulting in unfavorable stabilization of the graft and associated bone regeneration . simultaneous implant placement during sinus augmentation procedures frequently requires a minimal alveolar bone height , which when not present forces clinician to defer implant placement resulting in extended treatment duration and multiple surgical appointments . the present case report is about a piezosurgery assisted lateral wall osteotomy approach for sinus augmentation associated with membrane repair with simultaneous implant placement in the posterior maxilla .
PubmedSumm118898	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: maternal oral health knowledge , behaviors and beliefs such as feeding practices , oral hygiene maintenance for the child , failure to access professional dental care , and the beliefs that a child is not susceptible to caries or that primary teeth are not important are associated with early childhood caries ( ecc ) . these maternal beliefs and oral health practices appear to place a child at greater risk of developing dental caries . also , mothers ' oral health status is a strong predictor of the oral health status of their children . ecc is a multifactorial disease involving biological , microbial , and behavioral factors and the three etiological factors must simultaneously be present for initiation and progression of the disease . there is strong evidence that s. mutans and lactobacilli are the primary agents involved in the development of caries in both children and adults . studies using genetic / molecular techniques have shown that the source of the s. mutans infection in children is , predominantly although not exclusively , attributed to vertical transmission from the mothers . high levels of s. mutans andlactobacilli in the mother 's mouth contribute to maternal transfer as do maternal dietary habits and poor oral hygiene . maternal behaviors such as tasting the infant 's food and sharing utensils can transmit bacteria from the mother to the child . maternal psychosocial factors , including stress , oral health beliefs , fatalistic attitudes , and cultural factors , are associated with ecc and with dental health services utilization [ 1 , 79 ] . other characteristics such as maternal oral health literacy , self - efficacy , and ethnic and cultural - specific beliefs about oral health can be contributing factors to ecc [ 9 , 10 ] . because a child 's oral health is largely dependent on maternal biological and psychosocial factors , ecc becomes a women 's health issue , making it imperative to engage mothers in behavior change methods beginning at a child 's birth , or even prenatally . american indian ( ai ) children have the highest rate of ecc of any population group within the united states . american indian mothers living on reservations often are disproportionately burdened with the social disadvantages associated with unemployment , low levels of education , and poverty . these environmental factors may contribute to maternal psychological distress and , along with other factors such as low self - efficacy , social support , and inadequate preventive health services , can place ai children at still higher risk of ecc . our data have demonstrated that ai parents who do not adhere to recommended oral health behaviors also report more chronic distress than others . they also had poor oral health knowledge and demonstrated external locus of control , suggesting little confidence in their ability to influence their children 's oral health . in fact , the oral health of these ai children was significantly worse than that of children whose parents had greater oral health knowledge and more positive attitudes . these data suggested that working to improve maternal behavior , knowledge , and attitudes might lead to improved oral health in ai children . an oral health prevention trial for behavior change using motivational interviewing ( mi ) in ai mothers is underway in a northern plains tribal region . we speculated that when mothers learn more about oral health during mi sessions and engaged in supportive discussions about the importance of oral health practices and appropriate action steps , they will be better able to formulate oral health care goals for their children and develop the confidence and motivation needed for behavior change . however , several challenges were faced by investigators and research field staff in recruiting and engaging these mothers in the study . this paper describes the challenges and barriers faced by the field staff for an oral health prevention trial as they worked to engage ai mothers living in rural and remote locations . we also discuss the strategies developed as these staff worked to overcome the challenges they faced . in 2008 , the center for native oral health research at the university of colorado anschutz medical center was funded by the national institute for dental and craniofacial research ( u54de019259 ) to conduct a randomized controlled trial to determine whether a behavioral intervention using mi with ai new mothers will achieve a greater reduction of caries experience in children younger than three years than would enhanced community services alone . six hundred mothers and their newborns were enrolled and randomized to one of two groups over two years , with a period of follow - up lasting until the child 's third birthday . the trial has been approved by the tribal research review board and the colorado multiple institutional review board . this study was a qualitative evaluation of the challenges faced by the field staff in engaging ai mothers in the prevention trial ; as such , it falls under the purview of quality assurance and management of data collection for the trial and is not subject to irb review , other than what is required for the clinical trial . the authors created a semistructured interview guide and conducted in - depth interviews , lasting 4050 minutes each , with the five field staff members , who carried out the intervention . verbal consent was obtained from the staff members who participated in the interviews , and participation was voluntary . staff members were requested not to identify other staff members or themselves during the interviews to maintain confidentiality . all digital recordings are stored on a secure server . following standard qualitative analysis procedures [ 16 , 17 ] , after initial coding was completed , codes were iteratively refined as various themes and subthemes emerged as shown as follows . challenges . engaging the mothers : low priority , lack of knowledge , distractions . balancing potential conflicts between research policy and cultural norms . not being american indian . no gender based challenges . engaging the mothers : low priority , lack of knowledge , distractions physical and environmental barriers : poor road conditions , lack of transportation and communication , remoteness of data collection sites . physical and environmental barriers : poor road conditions , lack of transportation and communication , remoteness of data collection sites . poor road conditions , lack of transportation and communication , remoteness of data collection sites . strategies . new communication methods . interacting with the community at various venues . culturally sensitive strategies . the field staff described several challenges they faced in implementing the research , particularly those related to engaging new mothers in the study and the mi intervention . the staff pointed out that some mothers living on the reservation placed low priority on the oral health of their children , thus making it difficult to recruit them into the study . reflecting on the fact that ai families living on the reservation often have to deal with unemployment , food insecurity , and problems related to inadequate housing and transportation , they expressed empathy and understanding that oral health often was not the highest priority for some of these mothers . staff comment : mothers deal with so many things here , they want to participate in something like this , they want the best for their children but it is almost impossible.the field staff described that ai mothers had relatively little knowledge about oral health ; for instance , they often did not have knowledge about the importance of primary teeth or about the causes of dental caries . moreover , the main source of their knowledge was their mothers and extended family . mothers deal with so many things here , they want to participate in something like this , they want the best for their children but it is almost impossible . staff comment : i think my biggest challenge is ignorance ; they just do not know . and the other challenge is to get them to think differently than their mothers and grandmothers.pointing out that many study visits are done in the participants ' homes , staff noted that the mothers often were distracted by older children or by household chores and could not always fully engage with the staff who were there for an mi session or for conducting the dental assessment for the child . and the other challenge is to get them to think differently than their mothers and grandmothers . staff comment : the main challenge that i face in engaging new mothers is distractions , mainly their other older kids who want attention.though all the staff are from the community , some of them are not american indian , and this sometimes makes it difficult to create trust and thereby makes the job of recruiting mothers more difficult . the main challenge that i face in engaging new mothers is distractions , mainly their other older kids who want attention . staff comment : i think it is also different for me because i am a caucasian person , i am not from here and for me it is different to come in here , i am the outcast here , i am the different person here.all the field staff members are women , and they indicated that they have not faced any gender based challenges or barriers in engaging the mothers in the study . in fact , they said that being a woman was helpful in building rapport with the study participants . they believed that participants felt safer and more comfortable inviting women into their homes and sharing their stories with them . i think it is also different for me because i am a caucasian person , i am not from here and for me it is different to come in here , i am the outcast here , i am the different person here . staff comment : i always get positive responses from mothers as i am a mom too . i think mothers are more attentive to other women.the staff described some physical and environmental barriers they encountered that prevented them from being more productive in improving participant engagement in the study . they spoke about the vastness and remoteness of the reservation , poor road conditions , inclement weather , and poor communication methods all of which could be overwhelming and delay the process of reaching out to study participants . they thought that not reaching the participants at a given time could send the wrong signals related to their role in helping new mothers in reaching oral health goals for their child . staff comments : i guess the number one difficulty is that everything is so spread out and so far away . you have to have a vehicle to survive around here.just access , whether we are going to them or they ( study participants ) are coming to us . anytime it rains or snows it reduces our ability to reach to them as the roads are muddy.despite all the challenges they have faced , the staff have developed innovative ways to engage the mothers and the ai community at large in this oral health prevention trial . they informed us in the interviews that they are using new communication strategies such as facebook and sending postcards to interact and engage new mother on the reservation . i guess the number one difficulty is that everything is so spread out and so far away . just access , whether we are going to them or they ( study participants ) are coming to us . anytime it rains or snows it reduces our ability to reach to them as the roads are muddy . staff comment : people have no phone , no car , but they have facebook 24/7.they said they interact with the mothers at various community events , health clinics , and after - school programs for the children . this has not only provided ways to gain the trust of the community and the study participants but also increased their interest in oral health in general . they said they try to be culturally sensitive and are adapting to the local culture . people have no phone , no car , but they have facebook 24/7 . staff comment : when i call them i talk to them as if they are my friends on an everyday basis rather than clients or a participant in the study . when i call them i talk to them as if they are my friends on an everyday basis rather than clients or a participant in the study . results from this qualitative assessment reveal a number of difficulties of engaging ai mothers in an oral health intervention for their children , even though ai children have the highest need for such preventive interventions . one of the challenges is to prioritize the child 's oral health for ai mothers and to increase their acceptance of such interventions . though there are many physical and environmental barriers in reaching out to these mothers , the most salient challenge is to get them interested in the prevention of oral disease and then to help them develop an understanding of oral health issues and the steps they can take to prevent oral disease in their children . the use of motivational interviewing ( mi ) in this trial is helping to prioritize the oral health of children for the participating mothers and the families . mi is complementary to the cultural values of ai / an people ; it emphasizes listening , learning , and respect , and it creates space to include spirituality and religious practices , all of which are essential to engage and elicit behavior change in ai mothers . previous studies have recommended including oral health in anticipatory guidance during prenatal visits for indigenous women and using community - based promotion initiatives to emphasize the importance of oral health for pregnant women and their infants , which might help to prioritize oral health in all indigenous children since birth . data from this study and the previous work reported in the research literature have shown that maternal physical and psychosocial health and oral health knowledge are associated with oral health in their children , or with oral health behavior on behalf of their children . for example , mother 's self - efficacy is strongly associated with frequency of brushing child 's teeth . a number of false beliefs have been found , including the idea that primary teeth are not important because they fall out and the child will get a second chance with the permanent teeth . we also have found that , in ai populations , oral health decisions for children often are made by multiple members of the family , and some of those family members may discourage preventive oral health practices and support accessing dental care only when there is a serious problem . research staff in the study are overcoming the barriers of conducting research in remote and rural settings and developing successful strategies to engage new mother in oral health interventions by gaining trust of the community and being sensitive to local norms . these include conducting home visits , applying new communication strategies ( facebook ) , and interacting with the community at various venues . by providing flexibility to accommodate the work and childcare schedules of the study participants , conducting home visits , and participating in community events and pow wows , the field staff not only have gained the trust of the participants and the community but also have been able to spread awareness about oral health in general . involving the ai communities as active members of research and adapting engagement approaches according to community or tribal feedback are some of the successful strategies reported in the literature [ 20 , 21 ] . these approaches were welcomed by the mothers and the ai community more generally and suggest that interacting with mothers , who are the main gatekeepers for a child 's oral health , targeting behavior change in them , and building capacity at the family and community level could reduce ecc in ai children . future oral health prevention interventions can utilize these tested strategies and approaches to successfully engage mothers and increase oral health awareness for the family at large . clearly , the prevention of ecc needs to target ai mothers ; improving their oral health knowledge and decision making capacity could bring about family - level and community - level changes in preventing ecc . Output:	objective . this study explores the challenges faced by the research implementation team in engaging new mothers in a community oral health prevention intervention in an american indian ( ai ) reservation community . methods . qualitative methods in the form of in - depth interviews were used in the study . qualitative data were collected from research staff workers at a field site , who were involved in the implementation of a culturally tailored , randomized controlled trial of a behavioral intervention utilizing motivational interviewing ( mi ) . results . several challenges were described by the field staff in engaging new mothers , including low priority placed on oral health , lack of knowledge , and distractions that reduced their ability to engage in learning about oral health of their child . other difficulties faced in engaging the mothers and the ai community at large were distrust related to racial differences and physical and environmental barriers including poor road conditions , lack of transportation and communication , and remoteness of data collection sites . the field staff developed and applied many strategies , including conducting home visits , applying new communication strategies , and interacting with the community at various venues . conclusion . prevention interventions for ecc need to target ai mothers . strategies developed by the field staff were successful for engaging mothers in the study .
PubmedSumm118899	*TASK* the task is to summarize an input biomedical literature in six sentences *INPUT* the input is a biomedical literature *OUTPUT* the output is the summary of an input biomedical literature in six sentences *DOCUMENTATION* *EXAMPLES* Input: siewert first described the combination of situs inversus , chronic sinusitis , and bronchiectasis in 1904 . however , manes kartagener first recognized this clinical triad as a distinct congenital syndrome in 1933 . the immotility is due to variety of ultrastructural defects in respiratory cilia and sperm tail . afzelius was the first to recognize the relationship between ks and male infertility when he observed lack of dynein arms in the sperms and cilia of four subjects , three with ks and a fourth one , brother of one of the three subjects . however , our patient was 12 years old ; hence , we did not have spermatozoa for microscopic diagnosis . a twelve year - old boy came to our institute with complaints of recurrent sore throat and cough with yellowish expectoration intermittently for past three to four years with episodes of fever ; weight loss of about two to three kg over past one year ; chronic wheezing ; and chronic use of antibiotics for past two to three years with occasional steroids . the patient was a moderately built fair young boy , who was dyspneic , coughing , and short of breath . auscultation of the chest revealed diffuse bilateral ronchi with scattered crepitations over both infrascapular regions . surprisingly , we could not hear his heart sounds on the left side , but they were appreciable over right side and those were normal cardiac sounds . apex beat was palpable over the fifth intercostal space on the right side of chest . we did an electrocardiogram ( ecg ) on him with both right and left - sided chest leads , which revealed inverted the ecg was normal on right - sided chest leads [ figures 2 and 3 ] . chest x - ray showing dextrocardia computed tomography showing situs inversus computed tomography showing bronchiectasis the ultrasonography of abdomen revealed situs inversus , but rest of the scan was normal . his high resolution computed tomography ( hrct ) chest revealed bronchiectatic changes [ figure 4 ] and ct abdomen again confirmed situs inversus [ figure 5 ] . color doppler showing transposition of the aorta and ivc computed tomography pns ( coronal cut ) showing fused bulla with uncinate process 2d echo was consistent with dextrocardia ; all four chambers were normal . anti nuclear antibody , anti nutrophilic cytoplasmic antibody , and human immunodeficiency virus serolgy were negative . gram stain of the sputum revealed numerous gram positive cocci in pairs and gram negative bacilli . he was operated for sinusitis ( functional endoscopic sinus surgery ) at the same institute by our ent team . subsequently , he was advised vaccination for influenza and pneumococcal vaccine , inhaled steroid and bronchodilator , a mucolytic , and antibiotic course with regular follow - up in ent , pulmonology , and internal medicine opd . after 2 months of follow - up , the patient is doing well , although he continues to have intermittent cough of mild intensity . the patient was a moderately built fair young boy , who was dyspneic , coughing , and short of breath . auscultation of the chest revealed diffuse bilateral ronchi with scattered crepitations over both infrascapular regions . surprisingly , we could not hear his heart sounds on the left side , but they were appreciable over right side and those were normal cardiac sounds . apex beat was palpable over the fifth intercostal space on the right side of chest . we did an electrocardiogram ( ecg ) on him with both right and left - sided chest leads , which revealed inverted the ecg was normal on right - sided chest leads [ figures 2 and 3 ] . chest x - ray showing dextrocardia computed tomography showing situs inversus computed tomography showing bronchiectasis the ultrasonography of abdomen revealed situs inversus , but rest of the scan was normal . his high resolution computed tomography ( hrct ) chest revealed bronchiectatic changes [ figure 4 ] and ct abdomen again confirmed situs inversus [ figure 5 ] . color doppler showing transposition of the aorta and ivc computed tomography pns ( coronal cut ) showing fused bulla with uncinate process 2d echo was consistent with dextrocardia ; all four chambers were normal . anti nuclear antibody , anti nutrophilic cytoplasmic antibody , and human immunodeficiency virus serolgy were negative . gram stain of the sputum revealed numerous gram positive cocci in pairs and gram negative bacilli . he was operated for sinusitis ( functional endoscopic sinus surgery ) at the same institute by our ent team . fused portion was opened using microdibrider and frank pus was found in both bulla ethmoidalis . subsequently , he was advised vaccination for influenza and pneumococcal vaccine , inhaled steroid and bronchodilator , a mucolytic , and antibiotic course with regular follow - up in ent , pulmonology , and internal medicine opd . after 2 months of follow - up , the patient is doing well , although he continues to have intermittent cough of mild intensity . sinusitis , bronchiectasis , situs inversus and male infertility occurring in this condition are attributed to abnormal ciliary motility . these patients had poor mucociliary clearance because the cilia that lined their upper airways were not functioning . each ciliated cell gives rise to approximately 200 cilia that vary in length from 5 to 6 m and decrease in size as the airway becomes smaller . patients with primary ciliary dyskinesia exhibit a wide range of defects in ciliary ultrastructure and motility , which ultimately impairs ciliary beating and mucociliary clearance . the most common defect , first described by afzelius , is a reduction in the number of dynein arms , which decreases the ciliary beat frequency . sturgess et al . described how the radial spoke , which serves to translate outer microtubular sliding into cilial bending , was absent in some patients with primary ciliary dyskinesia . cilia in other patients lacked central tubules ; however , instead of the central tubules , an outer microtubular doublet transposed to the cell of the axoneme was present that displayed an abnormal 8 + 1 doublet - to - tubule pattern . the diagnostic criteria recommended for this syndrome are history of chronic bronchial infection and rhinitis from early childhood , combined with one or more of following features : ( a ) situs inversus or dextrocardia in a patient or a sibling , ( b ) living but immotile spermatozoa , ( c ) tracheobronchial clearance , which is absent or nearly so . our case had all these features ; however , due to age , immotile spermatozoa could not be demonstrated . treatment of this rare congenital disorder includes antibiotics , intravenous or oral , intermittent or continuous , and are used to treat upper and lower airway infections . obstructive lung disease / bronchiectasis should be treated with inhaled bronchodilators , mucolytics , and chest physiotherapy . the evidence base is largely anecdotal , but there may also be a role for inhaled antibiotics , inhaled and oral corticosteroids , and recombinant dnas . influenza and pneumococcal vaccination should be encouraged . endoscopic sinus surgery and the formation of a nasal antral window underneath the inferior turbinate may afford a transient improvement in upper and lower respiratory tract symptoms . taiana and associates reported on successful pulmonary operations in a 25-year - old man , consisting of left lower lobectomy , lingulectomy , and anterior segmentectomy of the left upper lobe . lung transplantation and heart - lung transplantation have occasionally been tried in severe cases with some success . on follow - up , our case improved significantly after endoscopic sinus surgery and the incidence of recurrent infections reduced drastically , which emphasizes the fact that early diagnosis and treatment of associated complications of this rare syndrome significantly improves the quality of life and prognosis of the patients . late diagnosis with established bronchiectasis worsens the overall the prognosis , even with the best of treatment modalities . a high degree of suspicion about ks among pediatricians around the globe is the need of the hour . Output:	kartagener s syndrome is a very rare congenital malformation comprising of a classic triad of sinusitis , situs inversus and bronchiectasis . primary ciliary dyskinesia is a genetic disorder with manifestations present from early life and this distinguishes it from acquired mucociliary disorders . approximately one half of patients with primary ciliary dyskinesia have situs inversus and , thus are having kartagener syndrome . we present a case of 12 year old boy with sinusitis , situs inversus and bronchiectasis . the correct diagnosis of this rare congenital autosomal recessive disorder in early life is important in the overall prognosis of the syndrome , as many of the complications can be prevented if timely management is instituted , as was done in this in this case .

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