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PubmedSumm118700 | ***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 frequently used alone or in combination with statins to treat diabetic dyslipidemia and hypertriglyceridemia .
statins are also associated with rhabdomyolysis , and perhaps this raises concerns about possible adverse drug interactions .
rhabdomyolysis is a clinical and biochemical syndrome that results from skeletal muscle injury and involves the subsequent release of muscle cell constituents into the circulation .
the typical clinical presentation includes muscle weakness , myalgias and dark - colored urine due to myoglobinuria , and the diagnosis is usually based on elevated serum skeletal muscle enzyme levels .
rhabdomyolysis associated with fenofibrate monotherapy is extremely rare and may result in myoglobinuria with acute renal failure .
fenofibrate monotherapy is associated with the potentially fatal side effect of rhabdomyolysis , which induces acute renal failure .
we report a rare case of fulminant rhabdomyolysis of the psoas muscle with fenofibrate monotherapy in an 82-year - old man with chronic myelogenous leukemia ( cml ) . to the best of our knowledge ,
there are no reports of fenofibrate monotherapy leading to fulminant psoas rhabdomyolysis in a patient with cml .
the patient was an 82-year - old man in the chronic phase of cml who also had hypertriglyceridemia .
his past medical history was significant for imatinib mesylate ( gleevec ) treatment 400 mg daily for 4 years since his initial presentation .
he had tolerated the medication well and achieved a complete cytogenetic remission . then imatinib was stopped because of liver dysfunction .
six months later , he was started on 100 mg of fenofibrate daily , 4 months before presentation , to treat hypertriglyceridemia ( serum triglycerides : 380 mg / dl ) . before the initiation of fenofibrate therapy , the patient 's serum creatinine was 1.3 mg / dl and the thyroid - stimulating hormone concentration and liver function were within normal limits .
past medical history contained the following pertinent negatives : no recent viral illness , history of trauma , or epilepsy , and the absence of any other medications that could potentially be associated with rhabdomyolysis .
upon admission , the patient had generalized muscle pain and right abdominal pain and the following laboratory values : white blood cell count , 186,400/l ; aspartate aminotransferase ( ast ) , 1,677 u / l ; alanine aminotransferase ( alt ) , 619 u / l ; ldh , 3,380 u / l ; triglycerides , 234 mg / dl ; total cholesterol , 117 mg / dl ; myoglobin , 990 g / ml ; creatine , 4.1 mg / dl ; and creatinine phosphokinase ( cpk ) , 5,882 iu / l . the red blood cell and platelet counts were within normal limits .
the elevated cpk was not cardiac in origin because both electrocardiography and myocardial enzyme markers were within normal limits .
an abdominal computed tomography ( ct ) scan and ultrasonography showed a large and low attenuation and high echogenicity , respectively , in the right middle retroperitoneal area ( fig .
, a large hematoma and necrotic mass was found in the right psoas muscle ( fig .
histological examination of the resected specimens revealed a psoas muscle with disproportionate fiber sizes and degenerating fibers surrounding the inflammatory reaction .
these findings , along with the clinical history , confirmed a diagnosis of fenofibrate - induced rhabdomyolysis ( fig .
fenofibrate is effective in reducing serum ldl cholesterol and triglyceride concentrations [ 2 , 3 ] .
it has been shown to increase the serum concentration of hdl cholesterol and reduce the serum concentration of dense ldl cholesterol .
fenofibrate in combination with statins is being used more frequently for the treatment of combined hyperlipidemia and to lower non - hdl cholesterol .
statins are also associated with rhabdomyolysis , and perhaps this raises concerns about possible adverse drug interactions .
the side effects of fibrate treatment include gastrointestinal complaints , gallstones , and skin reactions , all of which are tolerable and reversible .
the most important side effect of fibrates is rhabdomyolysis [ 4 , 5 ] . all fibrates , either as monotherapy or in combination with statins or other agents , are associated with rhabdomyolysis .
gemfibrozil had the highest reported rates of rhabdomyolysis , followed by bezafibrate , fenofibrate , ciprofibrate , and clofibrate .
this condition presents as myalgias , weakness , fatigue , and dark - colored urine , which usually develop within a few days of starting the treatment .
rhabdomyolysis associated with fibrates appears 3 weeks to 3 months after the initiation of the medication .
it has been suggested that fibrates cause a cell - specific injury to human embryonal rhabdomyosarcoma cells in vitro via the activation of the nuclear receptor peroxisome proliferator - activated receptor - alpha , through which the lipid - lowering action of fibrates is facilitated .
it was hypothesized that fibrates only exacerbate latent preexisting mitochondrial myopathies or accelerate the normal physiologic changes in skeletal muscle .
we have reported a case of fulminant rhabdomyolysis of the psoas muscle in an 82-year - old man with chronic myelogenous leukemia ( cml ) .
the rhabdomyolysis of the psoas iliac muscle was detected using tc-99 m hmdp bone scintigraphy .
a case of fulminant rhabdomyolysis of the psoas muscle , which needed an operation , has not previously been reported .
myalgias and muscle complaints are common side effects in patients who take imatinib for cml .
elevations of cpk are described in only 0.1 - 1% of patients , according to the manufacturer 's labeling .
cases of muscle edema and rhabdomyolysis have rarely been reported [ 11 , 12 ] .
these are the etiologic mechanisms of imatinib - induced cpk elevation , and occur early in the course of treatment .
the patient in the current report had tolerated the medication well and was in complete cytogenetic remission .
oliguric or nonoliguric acute renal failure is the most common complication of rhabdomyolysis , occurring in 10 - 40% of patients .
the current report describes a rare case of rhabdomyolysis in a patient with cml associated with fenofibrate monotherapy .
fenofibrate monotherapy is associated with the potentially fatal side effect of rhabdomyolysis , which induces acute renal failure . to the best of our knowledge ,
this is the first report of fenofibrate monotherapy resulting in fulminant rhabdomyolysis of the psoas muscle .
Output:
| rhabdomyolysis associated with fenofibrate monotherapy is extremely rare . here , we report a rare case of rhabdomyolysis of the psoas muscle in an 82-year - old man with chronic myelogenous leukemia ( cml ) . he was prescribed fenofibrate because of a hypertriglyceridemia .
the patient reported generalized muscle pain and right abdominal pain while receiving fenofibrate monotherapy .
an abdominal computed tomography scan and an abdominal ultrasound showed a large and low attenuation and high echogenicity , respectively , in the right middle abdominal area .
laboratory values included a serum creatine concentration of 4.1 mg / dl and a creatinine phosphokinase concentration of 5,882 iu / l .
during laparotomy , a large hematoma and necrotic mass was identified in the right psoas muscle .
histological examination revealed that the resected specimens were of the psoas muscle with irregular fiber sizes , degenerating fibers surrounding the inflammatory reaction , and fiber necrosis that is typical for polymyositis .
based on these findings and the clinical history , a diagnosis of fenofibrate - induced rhabdomyolysis was made . to the best of our knowledge
, no patient has ever been diagnosed with fulminant psoas rhabdomyolysis due to a fenofibrate monotherapy .
this report details the rare case of rhabdomyolysis in a patient with cml associated with fenofibrate monotherapy and offers a review of the literature . |
PubmedSumm118701 | ***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: central retinal artery occlusion ( crao ) induced by emboli from carotid artery atherosclerosis , the most common cause of crao , is diagnosed based on sudden visual loss and characteristic fundus findings including narrowing of the retinal arteries and macular whitening around the fovea that is typically seen as a cherry - red spot .
arterial spasms , a relatively rare cause of retinal artery occlusion , can cause branch retinal artery occlusion with complete superficial retinal opacification .
we report a case of crao that presumably was caused by a vasospastic mechanism and characterized by a unique striated pattern of retinal edema in the macula .
a 56-year - old man was referred to our hospital about 48 h after sudden onset of painless central visual loss in his right eye ( od ) on a winter morning .
he had a more than 25-year history of systemic hypertension and smoking . at referral ,
the best - corrected visual acuity ( bcva ) was 0.03 od and 1.2 in the left eye ( os ) , and the respective intraocular pressure values were 12 and 16 mm hg .
funduscopic observation showed striated retinal whitening in the macular region , faint cotton - wool patches around the optic disc ( fig .
1a ) , and segmental narrowing of the retinal arteries near the optic disc edge ( fig .
a horizontal foveal spectral - domain optical coherence tomography ( sd - oct ) scan showed thickening of the inner retina ( fig 1c ) .
a horizontal sd - oct scan of the edematous region 0.5 disc diameter above the fovea showed discrete distributions of inner retinal thickening with patchy increases in reflectivity in the inner retina ( fig .
1d ) showed that the hyperreflectivity coincided with the retinal opacification around the venules and the lower reflectivity coincided with the nonedematous retinal tissue around the arterioles .
based on the pattern of onset and fundus findings , we diagnosed incomplete acute crao od and immediately started a venous drip injection of prostaglandin e1 ( pge1 ) .
fluorescein angiography performed after the initial pge1 drip showed an arm - to - retina circulatory time of 28 s and an early - phase filling defect in the small capillary networks in the macular region ( fig .
doppler echocardiography did not show arterial narrowing or endothelial plaque in either carotid artery . according to a reported protocol ,
the patient was treated with intravenous pge1 ( 80 g / day ) for 5 days and then oral pge1 ( 30 g / day ) for 1 month .
one month after onset , the bcva improved to 0.5 od and the striated retinal edema and most cotton - wool patches resolved ( fig .
sd - oct showed marked thinning of the inner retina in the macula ( fig .
typically , acute crao is characterized on fundus examination by a cherry - red spot surrounded by homogenous superficial retinal whitening , while cotton - wool patches are infrequently seen , and oct shows thickening in the entire inner half of the sensory retina with blood supply from the central retinal arteries .
thus , the appearance in the current case is atypical compared with the typical acute crao induced by a thrombus or embolus .
based on the findings that included sudden visual loss , retinal edema , and a filling defect of the macular capillary networks accompanied by segmental constriction of the retinal arteries and cotton - wool patches , we diagnosed this case as an incomplete form of crao induced by arterial vasoconstriction .
thus , winter onset , a history of systemic hypertension , and smoking might have been associated with the vasospastic crao in this case .
the fundus appearance in the current case seems identical to cases reported by kurimoto et al . , who described three cases of incomplete crao resembling purtscher - like retinopathy with scattered macular edema and cotton - wool patches , although the authors did not fully discuss the mechanism of the development of the scattered macular edema .
using the currently available modalities , we found that the alternating arrangement of the inner retinal edema is associated geographically with the distribution of the retinal vessels , i.e. , edema develops only around the retinal venules and no edema develops around the retinal arterioles .
accordingly , we propose that differences in oxygen saturation resulting in differences in the distances from the arterioles may explain the alternating pattern of retinal edema in incomplete crao .
pge1 administered systemically can improve the visual acuity if it is administered during the acute phase , i.e. , typically within 1 day after the onset of acute crao . the visual acuity in the current case recovered after administration of systemic pge1 2 days after onset .
thus , the effect of systemically administered pge1 in the current case is inconclusive . to avoid recurrent crao , our patient continued to take oral pge1 until 1 month after onset , although the need for sustained use of oral pge1 is undetermined . in conclusion
, we observed a unique fundus appearance of striped retinal edema with faint cotton - wool patches in a patient with incomplete crao due to vasospasm .
differences in the oxygen pressure gradient in the capillary networks due to differences in the distances from the arterioles may be the mechanism of periarteriolar - sparing retinal edema .
the patient provided written informed consent for publication of this case report and any accompanying images .
the authors declare that there is no conflict of interest regarding the publication of this paper .
Output:
| a 56-year - old man was referred to our hospital about 48 h after sudden onset of painless central visual loss in his right eye ( od ) on a winter morning .
he had a more than 25-year history of systemic hypertension and smoking .
funduscopic observation showed striated retinal whitening in the macular region , faint cotton - wool patches around the optic disc , and segmental narrowing of the retinal arteries near the optic disc edge .
based on the pattern of onset and fundus findings , he was diagnosed with vasospastic acute central retinal artery occlusion od , and a venous drip injection of prostaglandin e1 was started immediately .
optical coherence tomography showed bands of high and low density in the inner retina arranged alternately in the edematous area ; the bands corresponded to edematous and nonedematous areas , respectively , and geographically to venules and arterioles , respectively .
the best - corrected visual acuity of 0.03 at referral improved to 0.5 , and the striated retinal edema and most cotton - wool patches resolved 1 month after onset .
the oxygen pressure gradient in the capillary networks due to differences in the distance from the arterioles may be the mechanism of this unique periarteriolar - sparing retinal edema pattern . |
PubmedSumm118702 | ***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: coronary embolism as a cause of myocardial infarction is an uncommon finding.1 ) coronary embolism should be suspected in the context of a valvular prosthesis , dilated cardiomyopathy , rheumatic valvular disease , intracardiac shunts , infective endocarditis , chronic atrial fibrillation and hypercoaguable states including pregnancy.2 ) this list also includes distal embolization during primary percutaneous intervention for acute myocardial infarction ( ami ) .
percutaneous coronary intervention ( pci ) , thrombolysis and surgical treatment are management options available.1 ) here we report a case of ami due to migration of coronary emboli from a left main coronary artery ( lma ) thrombus during coronary angiography ( cag ) .
, he had a systolic blood pressure of 120 mmhg and a heart rate of 62 beats per minute .
an initial electrocardiogram ( ecg ) showed no definite st segment change and sinus rhythm ( fig .
initial creatine kinase - mb and cardiac troponin i levels were in the normal range .
cag revealed a filling defect of the distal left anterior descending artery ( dlad ) , distal left circumflex artery ( dlcx ) and lma ( fig .
we decided to aspirate the lma thrombus and to do pci at the dlad and dlcx .
on cag , the distal region of the 1st diagonal branch ( d1 ) and the obtuse marginal branch ( om ) were not visualized ( fig .
we thought that this event had developed due to coronary embolization that resulted from the migration of thrombi into the lma during cag .
we tried to aspirate the thrombus in the lma using a guiding catheter and to do balloon angioplasty in the dlad and dlcx .
however , the dlad , dlcx and om had thrombolysis in myocardial infarction ( timi ) grade 1 flow in spite of repeated balloon angioplasty .
applied platelet glycoprotein iib / iiia receptor antagonist ( abcimixab , reopro ) and balloon angioplasty of the dlad , om and dlcx were done sequentially .
creatine kinase - mb and cardiac troponin i levels were elevated to 349.4 ng / ml and 40.91 ng / ml , respectively .
follow up ecg showed a 3 mm st segment elevation at leads ii , iii , avf and v3 - 5 after angiography ( fig .
we thought that the ami developed due to distal embolization of the lma thrombus during angiography .
laboratory profiles associated with hypercoaguability such as lupus anticoagulant , protein c activity 102% ( nl 70 - 130% ) , protein s activity 74% ( nl 73.7 - 146.3% ) , d - dimer 0.36 g / ml ( nl 0.0 - 0.4 g / ml ) , antithrombin iii 91% ( nl 80 - 120% ) and homocysteine 12.2 mol / l ( nl 5.0 - 15.0
after 3 days of intravenous unfractionated heparin ( 25,000 iu / day ) , follow - up cag showed only slight resolution of the filling defect and only in the dlad , not in the om and dlcx ( fig . 3a and b ) .
after 1 year of this treatment , he experienced no chest pain and , on follow up cag , had no significant stenosis or intracoronary filling defects ( fig .
although rupture of atherosclerotic plaques and intracoronary thrombus formation is widely accepted as the main pathophysiological cause for the development of ami , four to seven percent of patients with ami do not have underlying coronary artery disease.1)3 ) coronary embolism as a cause of myocardial infarction is an uncommon but important entity in terms of both etiology and treatment.1 ) coronary embolism leading to myocardial infarction was first reported by virchow in 1856.4 ) previous cases of coronary emboli have been reported in association with valvular prosthesis , dilated cardiomyopathy , rheumatic valvular disease , intracardiac shunts , infective endocarditis , chronic atrial fibrillation and hypercoaguable states including pregnancy.2 ) in addition , primary percutaneous intervention for ami may be complicated by distal embolization of plaque or thrombotic debris , with infarct extension.5 ) henriques et al.6 ) reported distal embolization in patients treated with primary angioplasty is visible on the coronary angiogram in 15.2% of patients . in an unusual case , van gaal et al.7 ) showed that a localized thrombus at the site of plaque rupture may embolise , causing coronary occlusion downstream in the dependent vascular territory , as in our case .
the strategy of intervention varies according to the acuity of the clinical presentation . if coronary embolism results in myocardial infarction associated with st - elevation , various interventional procedures including fogarty maneuvers , sole balloon angioplasty , stenting or thrombus aspiration have been suggested .
however , in the case of non - st - elevation myocardial infarction , there is no conclusive evidence favouring an interventional or conservative strategy.8 ) these techniques are particularly advocated in the setting of acute coronary syndromes.9 ) in particular , coronary embolism associated with an lma thrombus is associated with increased and extensive myocardial damage and adverse clinical outcomes such as sudden death or ami.10 ) in some cases , aspiration thrombectomy has been successfully used for lma thrombus .
however , indications for this therapeutic approach are determined by coronary anatomy , clinical stability and the hemodynamic condition of the patient.10 ) ahn et al.11 ) reported intracoronary thrombosis treated with stent and abciximab .
we demonstrated that ami developed due to coronary embolism from an lma thrombus without any apparent cause of the systemic embolism , which progressed with angiography .
therefore , we thought that embolization of an lma thrombus should be considered in cases where , on cag , there are multiple coronary artery filling defects .
Output:
| coronary embolism is an uncommon cause of myocardial infarction .
a 48-year - old male presented with typical chest pain of an mi .
there was no definite st segment change on electrocardiogram ( ecg ) and no elevation of myocardial enzymes .
coronary angiography ( cag ) revealed occlusion of the distal left anterior descending coronary artery ( dlad ) , the distal left circumflex coronary artery ( dlcx ) , the diagonal branch ( d ) and the obtuse marginal branch ( om ) , with a large filling defect in the left main coronary artery ( lma ) that caused the myocardial infarction .
we considered the possibility that coronary embolization was caused by the migration of a thrombus in the lma during cag .
we did balloon angioplasty in the dlad , dlcx , om and d and treated the patient with glycoprotein iib / iiia receptor antagonist .
however , thrombi remained in the dlad , om , and dlcx .
after 3 days of anti - thrombotic treatment , follow - up cag revealed only slight resolution of thrombi in the lad .
after triple antiplatelet agent medication for 1 year , a follow - up cag showed a resolution of the thrombi in all coronary arteries . |
PubmedSumm118703 | ***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: halogen bonds have attracted increased
interest in molecular design
recently , offering alternatives to classical polar
interactions such as hydrogen bonds .
r ,
where x is chlorine , bromine or iodine acting as a lewis acid and
y can be any kind of lewis base . because of a deficiency in electron
density on the hind side of x along the r x bond axis , chlorine ,
bromine and iodine possess a characteristic region of positive electrostatic
potential , the -hole , which favors interaction with electron
donors .
halogen bonds involving main - chain
carbonyl oxygens were found to improve the binding of several ligands
to their target protein significantly . the most frequently observed halogen bonds
in protein
quantum chemical calculations also suggest that affinity and selectivity
of ligands can be increased by directed halogen sulfur contacts
with methionines . despite this potential
of halogen moieties to contribute favorably to ligand binding
, the
number of compounds containing heavy halides in standard libraries
for fragment - based screening is very low . here
, we have designed
a halogen - enriched fragment library ( heflib )
and screened this library for molecules binding to the y220c mutant
of the p53 tumor suppressor .
p53 is inactivated in virtually every
cancer either through direct mutation or through perturbation of its
associated pathways .
reactivation of p53 function in tumors has , therefore ,
become a prime target for therapeutic intervention .
most oncogenic p53 cancer mutations
are located in the dna - binding domain of the protein .
about one - third of these mutations simply destabilize this only
marginally stable domain , lowering its melting temperature so that
it rapidly unfolds at body temperature . in theory ,
wild - type function of these mutants
unfolding equilibrium toward
the folded state and also slow down the rate of unfolding .
we have
previously shown that the cancer hotspot mutant y220c , which accounts
for approximately 75 000 new cancer cases per year , is a particularly
suitable test case for developing and validating such compounds .
the mutation destabilizes the protein by creating
a surface crevice at a site that is distant from the functional interfaces
of the protein . from virtual screening
,
we discovered a carbazole - based small molecule , phikan083 , that binds
to this crevice with a kd of 150 m
and raises the melting temperature of the protein in vitro . using halogen - enriched fragment libraries ( heflibs )
,
we were able to exploit halogen bonding for lead discovery and apply
it to develop biologically active small molecules that stabilize the
p53 mutant y220c .
we used the previously solved structural features of the mutation - induced
surface crevice in y220c as starting points to design new leads .
the
central cavity has a number of water molecules that are displaced
upon ligand binding ( figure 1 ) .
one water molecule forms a hydrogen bond with the main - chain oxygen
of leu145 , which is embedded within a hydrophobic environment .
the
carbonyl is not saturated with hydrogen bonds in the complex of y220c
with the carbazole - based phikan083 compound ( figure 1b ) , whereas other small molecules
interact with this oxygen via an amino group .
quantum chemical calculations at mp2/tzvpp level revealed that the
carbonyl oxygen of leu145 is poised for halogen - bond interactions
with moieties binding to the central cavity , in addition to formation
of hydrogen bonds ( figure 1c , d ) .
we therefore
designed a heflib to exploit this additional chemical space in our
search for alternative scaffolds binding to the y220c mutant .
( a ) molecular surface of
the p53 mutant y220c bound to the carbazole derivative phikan083 ( pdb
code 2vuk ) .
the mutation - induced cavity can be subdivided into three parts : ( i )
a deep but narrow central cavity , colored in blue , which is occupied
by the carbazole ring ; ( ii ) an open rather shallow subsite 1 , colored
in red ; and ( iii ) subsite 2 , colored in green , which is flanked by
several prolines and main - chain oxygens .
( b ) ribbon diagram showing details of the binding mode
of phikan083 , in particular the role of leu145 at the bottom of the
central cavity . also shown are structural
water molecules in the ligand - free structure ( pdb code 2j1x ) that are displaced upon ligand binding .
one of these water
molecules sits at the bottom of the predominantly hydrophobic central
cavity and forms a hydrogen bond with the main - chain oxygen of leu145 .
( c and d ) potential for halogen - bond interactions with the carbonyl
oxygen of leu145 .
the iodine - interaction energy sphere is plotted
onto the carbonyl oxygen of leu145 in the y220c - phikan083 structure ,
showing that this oxygen at the bottom of the central cavity is poised
for interaction with iodine - containing ligands with maximum binding
energy .
blue regions have the lowest energy ; red regions have the
highest energy ( see supporting information for details ) .
the heflib was designed using criteria for fragment
selection similar
to the rule of three by congreve et al . but employing an upper limit of the number of
heavy atoms ( up to 22 ) rather than the original molecular weight - based
criterion ( mw 300 ) . as an additional cheminformatics selection
rule
, the molecules were required to contain heavy halides , such as
bromine and , in particular , iodine .
we chose 79 small , nonreactive ,
soluble halogenated aromatic compounds from standard vendors , tested
them using a thermal shift assay ( differential scanning fluorimetry ,
dsf ) and performed secondary screenings with h / n - hsqc nmr spectroscopy and isothermal titration calorimetry ( itc ) .
the most promising lead obtained was 2,4-diiodo-6-((methyl(1-methylpiperidin-4-yl)amino)methyl)phenol 3 , which bound to the mutation - induced cavity with a dissociation
constant , kd , of 184 23 m
as determined by nmr ( figure 2a ) . binding mode
of 3 in the mutation - induced pocket of
the p53 mutant y220c .
( a ) overlay of n / h
hsqc spectra of t - p53c - y220c without ligand ( red ) and increasing concentrations
of 3 ( 73 m , orange ; 145 m , yellow ; 291
m , green ; 582 m , cyan ; 2000 m , dark blue ) .
the
mutant is shown as a gray cartoon representation , with selected residues
in the cavity shown as stick models .
the ligand is shown as a yellow
stick model , and polar interactions with the protein are highlighted
with broken lines .
an unbiased simulated - annealing omit ( fo fc ) electron - density
map for the ligand is shown at a contour level of 3.0 . the
piperidine moiety of 3 protruding from the cavity was
not resolved in the crystal structure and has been omitted from the
model . to verify whether 3 shows halogen
bonding as an essential
binding interaction and to guide our further ligand design , we solved
the crystal structure of the y220c mutant bound to 3 ( 1.7-
resolution ) , revealing the detailed binding mode of the compound .
the benzene moiety sits at the center of the mutation - induced cavity
in y220c , flanked by three prolines ( pro151 , pro222 and pro223 ) , val147
and thr150 ( figure 2b ) .
one iodine atom sits close to
the sulfur atom of cys220 ( 4.1- distance ) , whereas the other
is further removed from the sulfur ( 5.4- distance ) and , most
importantly , forms an energetically favorable halogen bond with the
main - chain oxygen of leu145 .
the distance between the iodine and oxygen
atoms is 3.0 , which is significantly shorter than the sum of
the van der waals radii of the two atoms , consistent with
quantum chemical calculations on the nature of halogen bonds .
the halogen - bond angle ( c io )
is 172. the phenol group interacts with a conserved structural
water molecule , which in turn is stabilized by hydrogen bonds with
main - chain atoms of val147 and asp228 .
in addition , the phenol hydroxyl
forms an intramolecular hydrogen bond with the tertiary amine .
there
was no clear electron density to model the binding mode of the piperidine
ring in 3 , indicating a high flexibility of this moiety
in the complex ( figure 2b ) . with the binding mode of 3 confirmed by x - ray crystallography
, we developed a lead optimization
strategy as presented in figure 3 to extend
the ligand into subsites 1 and 2 of the y220c binding pocket .
dissociation
constants obtained by h / n - hsqc nmr and itc ,
as well as the increase in the melting temperature measured by differential
scanning fluorimetry ( dsf ) , are given in table 1 for selected compounds at different stages of the lead optimization
process .
compound 3 and its analogues are easily obtained
by reductive amination of the commercially available building block
3,5-diiodosalicylaldehyde ( 1 ) with a range of different
amines .
the salicylic acid derivative of this building block 2 bound to the mutation - induced cavity with a kd of about 800 m , which corresponds to a ligand
efficiency of 0.34 kcal / mol per non - hydrogen
atom .
we generated computer models of all possible products using
this building block and commercially available amines , and docked
them into the y220c structure to select suitable candidates for synthesis .
we employed a rigid scaffold match constraint using the binding mode
of 3 to fix the central scaffold , as halogen bonding
is not generally implemented in current docking tools .
optimizing
the amine moiety within subsite 1 ( red areas in figure 1a ) by this structure - guided design increased compound affinities
moderately .
the two amines with highest binding affinity were 4 and 5 , showing kds measured by nmr of 104 and 87 m , respectively .
the crystal
structure of the y220c complex with 4 showed essentially
the same binding mode of the central scaffold as observed for 3 .
in contrast to the crystal structure of 3 ,
the piperidine ring was well - defined .
it packs against residues 147150 ,
protruding from the central region of the pocket and extending into
the shallow subsite 1 and out into solvent ( figure 4a and supporting information figure s1 ) .
overview of the synthetic strategy based on the initial hit 3 resulting from heflibs screening .
variations in the amine
side chain ( 35 ) were created starting
from building block 1 by reductive amination ( red box ) .
variation in the halogen substitution pattern ( 68 ) for systematically studying the strength of the halogen
oxygen
interactions was done by using different building blocks ( blue box ) .
the established scaffold was further extended into subsite 2 by sonogashira
coupling of 4 with different acetylenes yielding analogues 913 ( green box ) .
crystal structures of y220c ligand complexes . shown
are
the binding modes of 4 ( a ) , phikan5116 ( b ) , and phikan5196
( c ) .
the protein is shown as a gray cartoon representation with selected
residues highlighted as stick models .
the halogen bond between the
iodine and the carbonyl oxygen of leu145 is indicated by a broken
magenta line ; additional polar interactions with the protein are shown
as green broken lines .
tm = tm(ligand - bound protein ) tm(free protein ) . for binders with a kd in
the low micromolar region , line broadening ( intermediate
exchange )
was observed instead of chemical shift perturbation . to evaluate the contribution of halogen bonding to
the observed
ligand affinities , we replaced the iodine moieties in 5 with the lighter halogens bromine and chlorine , which are expected
to form weaker halogen bonds based on theoretical calculations .
comparison
of data for the three ligands 6 , 7 and 8 with 5 ( see figure 3 ) demonstrates the importance of the iodine
oxygen halogen
bond ( table 1 ) ; substituting the iodine moiety
binding to leu145 by bromine resulted in a 4-fold decrease in kd , while substitution with chlorine severely
impaired binding of the compound to the y220c crevice and resulted
in a 20-fold loss in affinity .
in addition to reduced halogen bonding ,
reduced space filling by the smaller chlorine compared to iodine may
also affect binding affinity .
replacement of the other iodine in position
4 by chlorine resulted only in a 3-fold loss in affinity .
next ,
we extended the ligand into subsite 2 ( colored in green in
figure 1a ) , which required bridging the narrow
gap between cys220 and pro151 .
a significant benefit of our heflibs
strategy is that halogens not involved in essential interactions with
the binding site can be utilized by a multitude of pd - based cross - coupling
reactions for developing and decorating the original scaffold .
we
evaluated various possibilities in silico and found an acetylene linker
best suited to bridge this narrow gap between the central cavity and
subsite 2 .
the acetylene linker was introduced by a reaction of the
4-iodo moiety on the central scaffold with terminal acetylenes in
a sonogashira coupling reaction .
the first
compound with acetylene linker to be tested was 9 ( phikan5116 ) ,
exhibiting very similar binding affinity to that of the parent di - iodo
compound 4 .
hence , loss of the bulky 4-iodo moiety in
the central scaffold is compensated for by interactions formed by
the new substituent in 9 .
surprisingly , 10 , which has a propargylamine moiety instead of the propargyl alcohol
moiety in 9 , bound only weakly to p53-y220c , possibly
due to heavy desolvation penalties for this highly polar compound
( nmr kd 1.1 mm ) . in contrast ,
its t - boc - protected precursor , 11 ( phikan5174 ) ,
exhibited very tight binding to the mutation - induced crevice ( kd measured from itc = 15.5 m ) and substantially
stabilized the protein ( table 1 , figure 3 ) .
substitution of the free terminal hydroxyl group
in 9 by a phenoxy moiety resulting in compound 12 ( phikan5176 ) led to a 10-fold increase in binding affinity
predominantly due to a favorable ch- stacking of the phenyl
ring on pro153 .
finally , introducing an anilinic nh
group instead of the phenol ether resulted in 13 ( phikan5196 ) ,
the most potent y220c stabilizer identified to date . 13 bound to the mutation - induced cavity with a dissociation constant
of 9.7 m as determined by itc and raised the melting point
of the protein by about 3.6 k at 250 m compound concentration
( figure 5 ) .
concentration - dependent thermostabilization of the y220c
mutant by phikan5174 ( a ) and phikan5196 ( b ) measured by dsf . binding
of phikan5174 ( c ) and phikan5196 ( d ) to y220c as characterized by
itc . to validate
our ligand design results , we solved crystal structures of a series
of y220c ligand complexes at 1.41.6 resolution
( figure 4 and supporting
information figure s2 ) .
replacement of the iodine facing cys220
with an acetylene linker in our third - generation compounds had virtually
no effect on the binding mode of the central scaffold . in all ligand - bound
protein structures ,
oxygen halogen bond distance is consistently
between 3.0 and 3.1 ( representing only 8689%
of the sum of the van der waals radii ) , and the halogen - bond angles
( c io ) are between 169 and 173.
this verifies our quantum chemical calculations regarding energetically
favored iodine oxygen halogen bonds ( as shown in figure 1c , d ) , which formed the basis for the design of heflibs .
as anticipated , the acetylene group occupies the narrowest part of
the cavity between residues pro151 , cys220 and pro222 that leads into
the previously unoccupied subsite 2 , thus widening the scope for additional
interactions . the additional hydroxyl group in 9 , for
example , forms a hydrogen bond with the main - chain oxygen of pro151
( figure 4b ) .
this oxygen is also hydrogen bonded
with the amide of phikan5174 ( supporting figure
s2 ) .
key structural features of the tightest binding ligands
include the additional hydrophobic interactions linking pro153 to
pro222 .
12 and 13 , for example , are stabilized
by packing of a benzene ring against pro153 , allowing favorable ch
stacking interaction , and hydrophobic interactions with thr150 and
pro222 ( figure 4c and supporting
information figures s1 and s2 ) .
11 , however , combines
a hydrogen bond with the carbonyl group of pro151 and hydrophobic
interactions of the tertiary butyl moiety with the aforementioned
three residues ( supporting information figure
s2 ) .
the higher affinity of 13 compared to 12 results from an additional , albeit weak , hydrogen bond
formed between the benzamine moiety and the carbonyl oxygen of cys220
( hydrogen - bond distance of 3.2 ) .
overall , the structural and
biophysical data highlight the crucial role of the acetylene linker
for designing high - affinity ligands occupying both subsites of the
y220c binding pocket .
we tested the effects of 9 , 11 and 13 on the human gastric cancer cell lines
nugc-3 ( p53-y220c ) and nugc-4 ( wild - type p53 ) using a caspase 3/7 apoptosis assay at concentrations ranging from
6.25 to 100 m ( figure 6 ) .
9 , the weakest binder of the three ligands tested , showed no effect
on caspase activity in either nugc-3 or nugc-4 cells after 6 h at
37 c . the more potent binders phikan5174 and
phikan5196 ( 11 and 13 ) , on the other hand , induced apoptosis
in the y220c - containing nugc-3 cells in a dose - dependent manner .
onset
of apoptosis with 13 was observed at a concentration
of 50 m , whereas 11 induced apoptosis only at
100 m compound concentration , which is consistent with the
2-fold higher affinity of 13 toward the y220c mutant
measured in our in vitro studies .
in contrast , no significant effect
on apoptosis / caspase activity was observed in the nugc-4 cell line
with wild - type p53 under the same conditions , suggesting that the
apoptotic effects of 11 and 13 in the nugc-3
cell line are mutant - specific .
the compounds showed cytotoxic effects
at 50 and 100 m in both cancer cell lines in a y220c - independent
manner ( supporting information figure s3 ) .
future developments will be to increase the affinity to levels
that ensure target selectivity .
structure - guided scaffold decoration ,
in particular to probe subsite 2 interactions ( e.g. , based on phikan5196 , 13 ) , should be ideally suited for this purpose .
caspase-3/7 activities
are shown at different concentrations of phikan5116 ( a ) , phikan5174
( b ) , and phikan5196 ( c ) in nugc-3 ( p53-y220c ) and nugc-4
( p53-wt ) cell lines .
while phikan5116 does not induce
caspase-3/7 activation , apoptosis is induced by the more potent binders
phikan5174 and phikan5196 at high concentrations in y220c mutant cells
but not in wild - type cells .
we have designed a new class of biologically
active small - molecule
stabilizers of the p53 cancer mutant y220c , resulting in a significant
increase in affinity compared to the carbazole - based ligand phikan083
reported previously .
this class of compounds
has two key features : ( i ) a central scaffold anchored by halogen bonding
and ( ii ) an acetylene linker which targets an additional subsite of
the mutation - induced cavity . with its two iodine atoms ,
the lead fragment , 3 , identified from screening of a halogen - enriched library
is perfectly suited for the design of potent y220c binders and provided
a central scaffold with a very robust binding mode .
while one iodine
moiety facilitates ligand binding through energetically favorable
halogen bonding , the other iodine can be exploited for carbon
carbon
bond formation , such as the sonogashira coupling performed here , to
extend the ligand into subsite 2 .
we propose a general strategy
that uses halogen - enriched fragment
libraries ( heflibs ) for lead discovery , in addition to halogen bonding
having been successfully employed recently for scaffold decoration .
halogenated compounds are underrepresented in fragment libraries
because of the significant atomic weight of bromine and iodine . however ,
heflibs share the advantages of regular fragments , and as molecular
probes of small size they can explore binding sites for favorable
halogen - bond interactions , to identify unique binding modes that are
complementary to those obtained from classical fragment - based screening .
oxygen contacts ,
in particular , are stable across a multistep structure - based design
process .
we therefore suggest a more widespread use of heflibs in
molecular design and drug discovery .
this strategy may not only be
useful for tackling novel targets but also provide alternative leads
for well - established pharmaceutically relevant target proteins and ,
thus , circumvent patent restrictions .
all docking experiments were performed
using the gold v3.2 suite of programs
together with the scoring functions goldscore and chemscore at default parameters ,
as described previously .
the search efficiency
for the genetic algorithm was increased to 200% in automatic mode .
binding site residues were defined automatically by providing the
co - crystal structures of phikan083 ( pdb entry 2vuk ) or 3 as a template and using flood fill ( detect cavity
option enabled ) with an active site radius of 12 . for docking
of halogen - bond forming compounds derived from 3 ,
a scaffold
match constraint was used , with the central scaffold of 3 as a template .
further details of computational methods , and a description
of the quantum chemical calculations used to plot the iodine
oxygen
interaction energy sphere ( figure 1c , d ) are
given in the supporting information .
the stabilized
dna - binding domain of the p53 mutant y220c , t - p53-y220c , was expressed
and purified as described previously . for the expression of n - labeled protein for nmr experiments ,
m9 minimal medium with nh4cl ( 1
the screening compound 3 was purchased from chembridge ( san diego , ca ) with > 95%
guaranteed
purity .
compounds 58 were
synthesized by chembridge ( san diego , ca ) , and compounds 913 were synthesized by roowin ( romainville ,
france ) . for all compounds , compound identity and > 95% purity were
guaranteed by the supplier .
the effect
of compounds on the melting temperature of t - p53c - y220c was monitored
using sypro orange ( invitrogen ) as the fluorescent probe , which quantitatively
binds to the hydrophobic protein patches exposed upon thermal denaturation .
real - time melt analysis was performed using a corbett rotor - gene 6000
real - time qpcr thermocycler .
heating from 28 to 60 c ,
a constant heating rate of 270 k / h was applied . the protein ( final
concentration of 10 m )
was briefly mixed with sypro orange
( 10 ) in buffer ( 25 mm kpi ph 7.2 , 150 mm nacl , 1 mm tcep ) , and
compound ( 5 mm ) dissolved in dmso was added to give a final compound
concentration of 250 m in 5% ( v / v ) dmso .
the melting temperature
( tm ) of the protein ( 10 m ) in presence
of compounds was determined from the inflection point of the melting
curve .
melting temperatures were compared with control samples without
compound ( yielding tm dsf ) .
h / n - hsqc
spectra of uniformly n - labeled t - p53-y220c ( 75 m )
with and without compounds were acquired at 20 c on a bruker
avance-800 spectrometer using a 5-mm inverse cryogenic probe .
samples
were prepared by adding dilutions of compound from stock solutions
in dmso - d6 to a final concentration of
5% ( v / v ) dmso - d6 in buffer .
all hsqc spectra
were acquired with 8 transients per t1 data point , 1024 data points in t2 ,
and 64 complex data points in t1 , with
spectral widths of 11.0 khz for h and 2.7 khz for n , and a recycle delay of 800 ms .
after zero filling , forward
complex linear prediction in f1 and fourier
transformation , the digital resolution was 0.01 ppm / point for h and 0.13 ppm / point for n. chemical shifts were
considered significant if the average weighted h / n chemical shift difference (h / n ) = [ ( (h ) ) + ( (n)/5 ) ] was greater than 0.04 ppm .
to determine dissociation constants , at least five n / h hsqc spectra at different compound concentrations were measured .
spectra analysis was performed using sparky 3.114 and bruker topspin 2.0 software . to derive kd values ,
a quadratic saturation binding equation was
fitted to the concentration - dependent chemical shift changes of the
relevant shifting peaks : itc experiments
were conducted using a microcal ( amherst ) itc200 calorimeter .
protein
samples used in the cell unit were prepared to a final concentration
of 50200 m in 25 mm kpi , ph 7.2 , 150 mm nacl , 1 mm
tcep in 5% ( v / v ) dmso .
compounds for use in the syringe unit were
dissolved in the same buffer at 5% ( v / v ) dmso .
measurements were performed
at 20 c using injection steps of 2 l at a rate of 0.5
l / s ( initial injection : 0.5 l ) and 120 s spacing .
crystals of t - p53c - y220c were
grown by the sitting drop vapor diffusion method as described previously .
they were soaked in solutions of compound ( 30
mm or saturated solution ) in cryo buffer ( 19% polyethylene glycol
4000 , 20% glycerol , 10 mm sodium phosphate , ph 7.2 , 100 mm hepes ,
ph 7.2 , 150 mm kcl , 10 mm dtt ) for 13 h and flash frozen in
liquid nitrogen .
x - ray data sets were collected at 100 k at the diamond
light source , oxford ( beamlines i02 , i03 and i04 ) .
the
structures were solved by rigid body refinement with phenix using the structure of the ligand - free mutant
( pdb i d 2j1x ) as starting model .
data
collection and refinement statistics are shown in table 2 . the atomic coordinates and structure factors of the y220c ligand
complexes have been deposited in the protein data bank , www.pdb.org ( pdb i d codes 4agl , 4agm , 4agn , 4ago , 4agp , and 4agq ) .
rcryst and rfree = ||fobs| |fcalc||/|fobs| where rfree was calculated over 5% of the amplitudes chosen at random and not
used in the refinement .
they were maintained
in rpmi1640 medium with 10% fetal calf serum and 1% antibiotic stock
mix ( 10 000 u / ml penicillin , 10 000 u / ml streptomycin ) .
cell viability , cytotoxicity and apoptosis
were measured using the apotox - glo triplex assay kit ( promega ) following
the manufacturer s instructions .
briefly , cells were seeded
at 1 10 cells / well in packard viewplate blank clear - bottom
96-well microtiter plates . after 18 h
, cells were incubated with compounds
at different concentrations for 6 h at 37 c and 5% co2 . after treatment , 20 l of a mixture containing the cell - permeable
protease substrate
gf - afc ( marker for viability ) and the cell - impermeable
protease substrate bis - aaf - r11 ( marker for cytotoxicity ) was added
to each well .
the content was mixed by orbital shaking for 1 min ,
and cells were incubated for another 1 h at 37 c .
the fluorescence
signals to determine cell viability and cytotoxicity were recorded
on a pherastar plate reader using a 400/500 nm and a 480/520 nm optic
module , respectively .
luminescence was recorded using an orion microplate
luminometer ( berthold detection systems , germany ) after 30 min incubation
with caspase - glo 3/7 reagent ( 100 l / well ) at room temperature .
Output:
| the destabilizing p53 cancer mutation y220c creates a
druggable
surface crevice .
we developed a strategy exploiting halogen bonding
for lead discovery to stabilize the mutant with small molecules .
we
designed halogen - enriched fragment libraries ( heflibs ) as starting
points to complement classical approaches . from screening of heflibs
and subsequent structure - guided design , we developed substituted 2-(aminomethyl)-4-ethynyl-6-iodophenols
as p53-y220c stabilizers .
crystal structures of their complexes highlight
two key features : ( i ) a central scaffold with a robust binding mode
anchored by halogen bonding of an iodine with a main - chain carbonyl
and ( ii ) an acetylene linker , enabling the targeting of an additional
subsite in the crevice .
the best binders showed induction of apoptosis
in a human cancer cell line with homozygous y220c mutation .
our structural
and biophysical data suggest a more widespread applicability of heflibs
in drug discovery . |
PubmedSumm118704 | ***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: colorectal cancer is the third most common noncutaneous malignancy , and accounts for the second most frequent cause in cancer - related deaths .
oncologists have been aware that , compared with colon tumor , the diagnosis , staging and , treatment for rectal cancer have significant difference .
fortunately , local control and survival rate in colorectal cancer has been significantly improved with the improvement of operation and chemotherapy . in clinical laboratory , the levels of carcino - embryonic antigen ( cea )
several inflammatory biomarkers are valuable and easily available for the assessment of prognosis in patients with rectal cancer such as tumor necrosis factor ( tnf ) , interleukin ( il)-6 , and c - reactive protein ( crp ) .
moreover , crp has been involved with recurrence and prognosis in patients with rectal cancer . however , other laboratory markers also have been needed to monitoring tumor recurrence , metastasis , and prognosis .
uric acid ( ua ) is the product of purine metabolism in the body . in the past
recently , serum ua was found to be associated with various diseases , such as cardiovascular disease , acute ischemic stroke , and lung cancer .
a cross - sectional study found that elevated ua concentrations were not an independent risk factor of colorectal adenoma ; it might be considered as a risk indicator for metabolic syndrome - related colorectal adenoma .
in fact , serum ua has been regarded to be an antioxidant in the body , and presents a compensatory mechanism against inflammation .
adenoma is a developmental stage of rectal cancer , which is a progress from the adenoma - carcinoma sequence to invasive cancer , and inflammation may play a key role in metastasis of rectal cancer .
considering this , we tend to provide a hypothesis that rectal cancer metastasis may be related to serum ua in patients with rectal cancer .
accordingly , the aim of this study was to investigate the role of ua in assessing rectal cancer metastasis .
all patients who were diagnosed with rectal cancer at the first college of clinical medical science , china three gorges university and yichang central people 's hospital during the period 2013 to 2016 were selected from a prospective colorectal cancer database .
a total of 569 potential cases with rectal cancer were considered as candidates ; finally , there were 475 newly diagnosed patients with complete data in our study .
exclusion criteria included hyperuricemia , gout , cardiovascular disease , hypertension , diabetes , infectious disease , hepatic or renal insufficiency , and other malignancy .
we reviewed electronic patient records retrospectively ; clinical and laboratory data were extracted , including sex , age , imaging reports , histopathological records , total protein ( tp ) , alanine aminotransferase ( alt ) , aspartate aminotransferase ( ast ) , creatinine ( cr ) , urea nitrogen ( un ) , cea , crp , erythrocyte sedimentation rate ( esr ) , and ua . these laboratory parameters were evaluated when patients with rectal cancer experienced first laboratory tests in our hospital .
the study was approved by the ethics committee of the first college of clinical medical science , china three gorges university and yichang central people 's hospital , and all patients provided informed consent .
continuous variables were shown as mean standard deviation ( sd ) , and categorical variables as percentages . before analysis ,
continuous variables with normal distribution were analyzed by independent - sample t test , and non - normal distribution data were compared by rank - sum test . correlation analysis was carried out by spearman approach .
further , multiple logistic regression analysis was used to analyze factors possibly associated with rectal cancer metastasis . the receiver - operating characteristic (
roc ) curve was used to ascertain the sensitivity and specificity of serum ua as an estimator of rectal cancer metastasis .
all patients who were diagnosed with rectal cancer at the first college of clinical medical science , china three gorges university and yichang central people 's hospital during the period 2013 to 2016 were selected from a prospective colorectal cancer database .
a total of 569 potential cases with rectal cancer were considered as candidates ; finally , there were 475 newly diagnosed patients with complete data in our study .
exclusion criteria included hyperuricemia , gout , cardiovascular disease , hypertension , diabetes , infectious disease , hepatic or renal insufficiency , and other malignancy .
we reviewed electronic patient records retrospectively ; clinical and laboratory data were extracted , including sex , age , imaging reports , histopathological records , total protein ( tp ) , alanine aminotransferase ( alt ) , aspartate aminotransferase ( ast ) , creatinine ( cr ) , urea nitrogen ( un ) , cea , crp , erythrocyte sedimentation rate ( esr ) , and ua . these laboratory parameters were evaluated when patients with rectal cancer experienced first laboratory tests in our hospital .
the study was approved by the ethics committee of the first college of clinical medical science , china three gorges university and yichang central people 's hospital , and all patients provided informed consent .
all data were analyzed by using spss16.0 ( spss inc . , chicago , il ) .
continuous variables were shown as mean standard deviation ( sd ) , and categorical variables as percentages . before analysis ,
continuous variables with normal distribution were analyzed by independent - sample t test , and non - normal distribution data were compared by rank - sum test .
further , multiple logistic regression analysis was used to analyze factors possibly associated with rectal cancer metastasis . the receiver - operating characteristic (
roc ) curve was used to ascertain the sensitivity and specificity of serum ua as an estimator of rectal cancer metastasis .
a total of 475 cases were reviewed , and divided into patients with metastasis and without metastasis .
there were several statistical differences in age , tumor diameter , cea , and crp between the 2 groups .
importantly , serum concentrations of ua in patients with lymphatic metastasis were found to be increased compared with patients without lymphatic metastasis ( 270.9 52.99 vs 215.8 43.55 ; p < 0.001 ) . demographic and laboratory characteristics in metastatic nonmetastatic rectal cancer patients .
among these cases , correlation analysis showed that serum ua concentrations were positively correlated with cr , un , crp , and cea ( r = 0.327 , p <
0.001 ; r = 0.298 , p = 0.018 ; r = 0.305 , p = 0.002 ; r = 0.217 , p = 0.038 ) in all patients with rectal cancer . in addition
, there were positive correlations of serum ua with cr , crp , and cea ( r = 0.281 , p = 0.023 ; r = 0.312 , p = 0.001 ; r = 0.294 , p = 0.017 ) in rectal cancer patients with metastasis .
however , the correlations between increased serum ua concentrations and crp or cea were not found in rectal cancer patients without metastasis . after extensive univariate analysis , in comparison between the 2 groups , some significant variables that might be associated with tumor metastasis , to exclude other factors that might influence the association between ua and tumor metastasis in rectal cancer patients , all variables were included in the multivariable analysis to identify whether serum ua levels were related with tumor metastasis in rectal cancer patients .
therefore , age , sex , body mass index , tumor diameter , tumor location , alt , ast , tp , cr , un , crp , and cea were included in multiple logistic regression analysis , and the results found that increase in crp and cea concentrations was associated with metastasis , and tumor diameter also was related to lymphatic metastasis in patients with rectal cancer .
interesting , multivariate analysis model revealed that elevated serum levels of ua were significant prognostic marker for lymphatic metastasis in patients with rectal cancer , independently of crp , cea , and tumor diameter ( odds ratio [ or ] 1.035 , 95% confidence interval [ ci ] 1.0131.057 , p = 0.002 ; table 2 ) .
1 , was performed to estimate performance in identifying metastasis in rectal cancer patients ; the area under the curve of serum ua in assessing metastatic rectal cancer patients was 0.803 , with sensitivity of 0.864 and specificity of 0.739 .
receiver - operating characteristic ( roc ) curve of tumor diameter , cea , crp , and ua in identifying metastatic rectal cancer patients .
cea = carcino - embryonic antigen , crp = c - reactive protein , ua = uric acid .
we found that serum ua , cea , and crp was increased in rectal cancer patients with metastasis compared with those without metastasis , and higher serum ua levels were associated with metastatic rectal cancer patients in multiple logistic regression analysis .
however , we did not find the association between tumor location and tumor metastasis in patients with rectal cancer .
a large prospective study suggested that higher serum ua levels are associated with the outcome of more serious prognostic indication in patients with cancer .
serum ua level has been considered as an independent predictor of the prognosis in some cancer such as esophageal squamous cell carcinoma , nasopharyngeal carcinoma , and oral squamous cell carcinoma .
in addition , higher serum ua concentrations have been observed in cancer patients since nucleic acid turnover in proliferating diseased tissue .
indeed , serum ua concentrations have been demonstrated to be related to inflammation and oxidative stress in some non - neoplastic diseases .
mori et al found that serum levels of crp and cea were biological markers in the prognosis of patients with colorectal cancer . to our knowledge
, there is no study that directly confirmed the association between serum ua level and tumor metastasis in patients with rectal cancer . in the present study
, we observed that serum ua concentrations were positively correlated with crp and cea level in rectal cancer patients with metastasis , and increased serum concentrations of ua may predict metastasis in patients with rectal cancer .
presence of more severe inflammatory response may contribute to increased serum ua concentration in rectal cancer patients with metastasis .
growing data demonstrated that nuclear factor - kappa b signaling pathway and notch-1 play important roles in the ua - induced inflammatory response , and notch-1 is able to decrease inflammation and oxidative stress induced by ua . there were evidences that inflammation and oxidative stress can promote tumor cell proliferation and angiogenesis , and favor invasion and metastasis .
thus , the values of serum ua may be a good predictor of metastasis in patients with rectal cancer . in the current study
first , a relatively small sample size in this cross - sectional design is a major limitation .
moreover , some confounders associated with ua , such as diet , exercise , and alcohol consumption , were not included as variables in multiple regression analysis , and more clinical parameters for the severity of the disease were needed to explain the relationship between serum ua and metastasis status in multiple regression analysis .
finally , the association between ua and clinical prognostic significance was analyzed in patients with rectal cancer . despite these limitations
, our results suggest that serum ua may be a novel marker in assessing tumor metastasis in patients with rectal cancer .
the study was approved by the ethics committee of the first college of clinical medical science , china three gorges university and yichang central people 's hospital , and all patients provided informed consent .
the study was approved by the ethics committee of the first college of clinical medical science , china three gorges university and yichang central people 's hospital , and all patients provided informed consent .
Output:
| abstractthe aim of this study was to investigate the role of uric acid ( ua ) in assessing rectal cancer metastasis.there were 475 newly diagnosed patients with complete data in our study , a total of 475 cases were reviewed , and divided into patients with metastasis and without metastasis.there were several statistical differences in age , tumor diameter , carcino - embryonic antigen ( cea ) , and c - reactive protein ( crp ) between the 2 groups .
importantly , serum concentrations of ua in patients with lymphatic metastasis were found to be increased compared with patients without lymphatic metastasis ( 270.9 52.99 vs 215.8 43.55 ; p < 0.001 ) .
there were positive correlations of serum ua with creatinine ( cr ) , crp , and cea ( r = 0.281 , p = 0.023 ; r = 0.312 , p = 0.001 ; r = 0.294 , p = 0.017 ) in rectal cancer patients with metastasis .
multivariate analysis model revealed that elevated serum levels of ua were significant prognostic marker for lymphatic metastasis in patients with rectal cancer , independently of crp , cea , and tumor diameter ( odds ratio 1.035 , 95% ci 1.0131.057 , p = 0.002 ) .
in receiver - operating characteristic curve analysis , the area under the curve of serum ua in assessing metastatic rectal cancer patients was 0.803 , with sensitivity of 0.864 and specificity of 0.739.our results suggest that serum ua may be a novel marker in assessing tumor metastasis in patients with rectal cancer . |
PubmedSumm118705 | ***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:
several therapeutic strategies exist for the treatment of osteochondral lesions ( ocls ) of the talus [ 22 , 37 ] .
non - operative treatment consists of cast immobilization and non - weightbearing or weightbearing as tolerated along with a rehabilitation programme [ 13 , 26 ] . recently ,
platelet - rich plasma and hyaluronic acid injections have also been employed for treating talar cartilage defects .
common surgical techniques include arthroscopic debridement with curettage and drilling [ 3 , 19 ] , arthroscopic debridement with microfractures [ 6 , 8 ] , autologous chondrocyte transplantation [ 4 , 5 ] , autologous matrix - induced chondrogenesis [ 7 , 33 ] , and arthrotomy with osteochondral autologous or heterologous grafts .
the advantages of arthroscopic procedures for the treatment of ocls in the ankle are that they minimize invasiveness , reduce operating time , and allow a faster rehabilitation period and an earlier return to work in comparison with open procedures [ 10 , 11 , 23 ] . in the young and active population , ocls following sports - related injuries
are usually associated with the involvement of the external ligamental complex and with concomitant synovitis [ 24 , 28 , 30 , 35 ] , and thus , all aspects should be addressed during the treatment in order to maximize the outcomes . a four - step protocol , which consists of synovectomy , debridement and microfractures of the ocl , capsular shrinkage , and bracing and non - weightbearing , has been developed in the department of minimally invasive articular surgery of the g. pini orthopaedic institute of milan , italy .
the purpose of the present study was to retrospectively evaluate the outcomes of patients with sports - related ocls of the talus .
the hypothesis was that a comprehensive four - step approach would lead to a high success rate in patients affected by post - traumatic ocls of the ankle .
operative treatment was proposed to subjects with deep ankle pain symptoms during daily living or sports activities who were unresponsive to at least 6 months of non - operative treatment including physical therapy and proprioceptive training .
all subjects considered met the following inclusion criteria : age 1855 years , absence of previous ankle surgery , absence of multiple ligament insufficiency , cartilage defects less than 1.5 cm .
operative setting and preliminary arthroscopic inspection were made according to those described by the authors in a previous paper .
cartilage defects were first debrided with the use of a motorized 4.0-mm shaver ( tomcat , stryker endoscopy , san jose , ca , usa ; formula , stryker endoscopy , san jose , ca , usa).fig .
1operative procedure , including synovectomy ( a ) , debridement and microfracture of the ocl ( b ) , and capsular shrinkage ( c ) operative procedure , including synovectomy ( a ) , debridement and microfracture of the ocl ( b ) , and capsular shrinkage ( c ) after unstable cartilage had been excised and the overlying bone had been scraped , the defect area was curetted , and the area of the defect was perforated according to the technique described by steadman ( fig .
the shrinkage procedure was performed using a vapr t side effect thermal electrode ( mitek , westwood , ma , usa ) with a 3.5-mm tip at desication mode , a temperature setting of 70 c , and maximum power of 50 w. with the ankle placed in an everted position , the probe was swept from the anterior talo - fibular ligament ( atfl ) and progressing along the adjacent capsule based on visual observation of the macroscopic tissue contraction ( fig .
whenever the atfl presented a complete tear , ligament remnants were debrided before performing thermal shrinkage on the surrounding capsule in the same fashion as described by the authors in their previous study .
associate procedures such as the removal of loose bodies or osteophytes were performed if required . at the end of the procedure ,
the tourniquet was released to visualize bleeding of the ocl site , joint flushing was performed , portals were closed , and a sterile dressing was applied . immediately after the operation ,
for the first 3 weeks , patients were instructed to walk with non - weightbearing with the use of two crutches .
after the removal of the brace , patients were encouraged to regain weightbearing as tolerated and were instructed to perform proprioceptive and complete ankle range of motion ( rom ) exercises .
patients were examined pre - operatively and followed up after an average time of 4 years ( sd : 1.1 ) .
clinical assessment included the american orthopaedic foot and ankle society ( aofas ) ankle and hindfoot scoring system , karlsson - peterson score , tegner activity level , sefton articular stability scale , and objective examination comprehending rom , anterior drawer sign , and talar tilt test .
the test was considered either positive ( maximum manual translation more than 5 mm ) or negative ( manual translation less than 5 mm ) . magnetic resonance imaging ( mri )
patients were also asked to rate the success of their surgery as poor , fair , good , or excellent and to indicate whether they would undergo surgery again .
data were analysed using the program spss version 17.0 ( spss inc . , chicago , il , usa ) .
paired t - test ( two - sided test and = 0.05 ) was utilized to compare the pre - operative and follow - up status .
operative setting and preliminary arthroscopic inspection were made according to those described by the authors in a previous paper .
cartilage defects were first debrided with the use of a motorized 4.0-mm shaver ( tomcat , stryker endoscopy , san jose , ca , usa ; formula , stryker endoscopy , san jose , ca , usa).fig .
1operative procedure , including synovectomy ( a ) , debridement and microfracture of the ocl ( b ) , and capsular shrinkage ( c ) operative procedure , including synovectomy ( a ) , debridement and microfracture of the ocl ( b ) , and capsular shrinkage ( c ) after unstable cartilage had been excised and the overlying bone had been scraped , the defect area was curetted , and the area of the defect was perforated according to the technique described by steadman ( fig .
the shrinkage procedure was performed using a vapr t side effect thermal electrode ( mitek , westwood , ma , usa ) with a 3.5-mm tip at desication mode , a temperature setting of 70 c , and maximum power of 50 w. with the ankle placed in an everted position , the probe was swept from the anterior talo - fibular ligament ( atfl ) and progressing along the adjacent capsule based on visual observation of the macroscopic tissue contraction ( fig .
whenever the atfl presented a complete tear , ligament remnants were debrided before performing thermal shrinkage on the surrounding capsule in the same fashion as described by the authors in their previous study .
associate procedures such as the removal of loose bodies or osteophytes were performed if required . at the end of the procedure ,
the tourniquet was released to visualize bleeding of the ocl site , joint flushing was performed , portals were closed , and a sterile dressing was applied . immediately after the operation , an ankle brace was applied ( air - stirrup , aircast inc . , summit , nj , usa ) .
for the first 3 weeks , patients were instructed to walk with non - weightbearing with the use of two crutches .
after the removal of the brace , patients were encouraged to regain weightbearing as tolerated and were instructed to perform proprioceptive and complete ankle range of motion ( rom ) exercises .
patients were examined pre - operatively and followed up after an average time of 4 years ( sd : 1.1 ) .
clinical assessment included the american orthopaedic foot and ankle society ( aofas ) ankle and hindfoot scoring system , karlsson - peterson score , tegner activity level , sefton articular stability scale , and objective examination comprehending rom , anterior drawer sign , and talar tilt test .
the test was considered either positive ( maximum manual translation more than 5 mm ) or negative ( manual translation less than 5 mm ) . magnetic resonance imaging ( mri )
patients were also asked to rate the success of their surgery as poor , fair , good , or excellent and to indicate whether they would undergo surgery again .
data were analysed using the program spss version 17.0 ( spss inc . , chicago , il , usa ) .
paired t - test ( two - sided test and = 0.05 ) was utilized to compare the pre - operative and follow - up status .
one patient suffered further malleolar fracture on the operated ankle that was treated surgically , and one patient was lost at follow - up ; thus , 38 ankles were considered at follow - up .
the defects were mostly located in the anteromedial portion of the talus ( 31 ankles , 82 % ) , while in 7 cases ( 18 % ) they were located in the posterolateral talar region .
fourteen patients practised contact sports before injury ( martial arts , rugby , soccer , basketball , etc . ) , and 24 non - contact sports ( volleyball , running , tennis , etc . ) .
twelve practised sport at a competitive level , five of them as professionals , and the other 26 practised sport at the recreational level.table 1patient demographics and anthropometric datamedian age at surgery39 years ( range : 1852)gendermale23female15sideleft17right21mean body mass index ( bmi)26 ( sd : 3 ) patient demographics and anthropometric data an overview of the results is presented in table 2 .
the mean aofas and karlsson - peterson score significantly improved at follow - up ( p < 0.001 ) , as well as tegner activity level ( p < 0.001 ) .
return to sports occurred at an average of 15.4 weeks ( sd 3.1 ) after surgery .
articular stability as assessed by sefton scale documented a significant improvement ( p < 0.001).table 2overview of the results of clinical assessmentpre - operativepost - operativep valueaofas scale ( mean)60.2 ( sd : 7.8)89 . 4 ( sd : 7.1 ) ( < 0.001)karlsson - peterson score ( mean)62.7 ( sd : 9.9)90.1 ( sd : 7.8 ) ( < 0.001)tegner score ( median)4 ( range 25)4 ( range 35 ) ( < 0.001)sefton scale ( mean)2.9 ( sd : 0.9)1.8 ( sd : 0.8 ) ( < 0.001)positive anterior drawer test30 ( 79 % ) 1 ( 2.6 % ) ( < 0.001 ) overview of the results of clinical assessment twenty patients ( 52 % ) complained giving - way symptoms before surgery .
objective examination documented a statistically significant improvement in terms of ankle stability and demonstrated negative anterior drawer test in 37 ( 97.4 % ) patients .
results were compared to pre - operative manual laxity tests ( p < 0.001 ) .
rom was complete in 36 patients : one experienced 5 degrees dorsiflexion limitation and one patient 10 degrees less compared to the contralateral side .
concomitant arthroscopic findings are summarized in table 3 : most notably , atfl was found partially or totally ruptured in all subjects.table 3overview of concomitant arthroscopic findings and related treatmentpathologyno .
of patients%treatmentsynovitis38100synovectomyatfl lesion38100debridement and shrinkageloose bodies718removaltibiotalar bony impingement513bony spurs resectionatfl anterior talo - fibular ligament overview of concomitant arthroscopic findings and related treatment atfl anterior talo - fibular ligament complications that persisted at follow - up were observed in two patients ( 5.3 % ) who complained of permanent altered sensation of the anterolateral aspect of the foot .
mri scans taken at 18 months after surgery revealed filling of the defect in 27 ( 71 % ) cases . in 9 ankles ( 24 % ) , the treated area appeared partially repaired with slight bone marrow oedema which was still present . in 2 ankles ( 5 % ) ,
thirty - one patients ( 82 % ) rated the success of their surgery as good / excellent .
the most important finding of the present study was that the four - step technique presented is a valid therapeutic option for the treatment of osteochondral defects , since it contributes to fibrocartilage regeneration and confirms subjective and objective clinical improvement over a period of up to 6 years after surgery . secondly , the clinical and functional results of this study are similar or superior to those previously reported in patients treated for ocls of the talus with or without associated ankle instability , with no increased risk of complications . recently , several studies documented successful outcomes after bone marrow stimulation for the treatment of ankle ocls [ 6 , 8 , 14 , 27 , 32 ] , with optimal results observed in lesions smaller than 15 mm and in patients without concomitant factors that could negatively affect outcomes ( increasing age , higher body mass index , history of trauma , and presence of osteophytes ) .
the four - step operative treatment included synovectomy ( figure 1a ) , debridement and microfracturing of the ocl ( fig .
1c ) , and bracing and non - weightbearing for 21 days . in the sprained ankle
, synovitis is a common finding as it represents the reaction to an insult to the lateral ligament complex .
synovial hypertrophy was detected and treated in all patients who had suffered previous ankle sprain , similar to how described in a previous study by the same authors .
a strong association between ocls and ankle instability in athletes has been previously reported . in all the ankles examined in this case series
the resection of the borders of the avulsed ligament and the debridement of the adjacent area allow the stimulation of fibrous tissue and enhancement of the healing process of the atfl complex .
this procedure , together with the thermal shrinkage provided by radiofrequency , promotes the shortening of collagenous fibres within the connective tissue and leads to an effective reduction in capsular volume , thus enhancing joint stability [ 2 , 9 , 12 ] .
controversy exists regarding the concomitant treatment of ocls and lateral ankle instability , since different rehabilitation programmes exist for the two treatment strategies .
patients treated with microfractures would need early ankle motion to promote fibrocartilage healing , while immobilization with cast or brace is crucial to prevent lengthening of the treated tissue after thermal shrinkage . other papers addressing combined lateral ligament reconstruction and treatment of ocls report cast immobilization for three or 4 weeks . in this case series , the positioning of the air - stirrup brace during the first 3 weeks of the post - operative phase permitted the movement on the sagittal plane only , thus allowing earlier mobilization of the ankle without affecting ligament healing . in the patient group
considered , the positive results observed in subjective perception and functional scales were also confirmed by objective examination . at follow - up , all patients reported a reduction in pain and a functional improvement .
. reported on 35 ankles with isolated ocls of the talar dome which were treated with arthroscopic microfractures . at a mean follow - up of 33 months ,
however , differently from the cohort of patients reported in the present paper , no instability was found in any of the ankles considered .
takao et al . performed arthroscopic drilling of ocls of the talus in 69 unstable ankles that were treated with lateral ankle ligament reconstruction .
gregush and ferkel reported on 31 patients who underwent concomitant arthroscopic treatment of an ocl and lateral ankle stabilization in the same sitting after an average follow - up of 7.3 years .
the mean aofas score was 89 with no patients complaining of ankle instability at the time of follow - up . in the present study , mri scans taken 18 months after surgery documented complete filling of the defect in 71 % of cases .
the mri scans for two patients ( 5 % ) reported incomplete filling of the defect .
after 4 years , none of the patients expressed symptoms of giving way or any other complaint of secondary instability . in none of the subjects
was there noted persistent deep ankle pain affecting daily activities and causing joint swelling after sport or strenuous activity .
three patients ( 8 % ) reached a lower activity level at follow - up .
these patients did not return to their previous sport activity because of fear of reinjury .
no cases of wound infections nor recurrent instability was reported . in a previous paper on arthroscopic treatment of ankle instability by the same authors ,
5 cases ( 5.7 % ) of peroneal nerve injury persisting at follow - up were reported . in the present study , occurrence of neurologic complications
limitations of the present study include its retrospective nature , the lack of a control group , and the relatively small sample size .
the limited number of patients is due to the fact that this approach requires adopting highly selective indications as criteria for patient selection .
osteochondral talar dome lesions are strictly related to soft tissue pathology , and they may coexist because of the mechanism of injury [ 16 , 28 ] .
arthroscopic microfracturing itself could be insufficient for the treatment of sports - related ocls of the ankle since usually the presence of cartilage damage implies concomitant involvement of the lateral ligament complex .
the four - step procedure as suggested represents a comprehensive approach that can lead to reliable improvement in symptoms in the treatment of post - traumatic ocls ankle lesion in appropriately selected patients .
in addition , the four - step approach has multiple advantages compared to open techniques ( low complication rate , less operative time , no donor site morbidity ) and offers similar outcomes in comparison with previously reported case series .
a comprehensive four - step protocol as presented represents a safe and clinically effective treatment option in patients with post - traumatic ocls of the ankle .
Output:
| purposethe purpose of this retrospective study was to assess the treatment of post - traumatic osteochondral lesions ( ocls ) of the ankle with a four - step protocol.methodsthirty-eight patients with at least one mri - documented ocl of the ankle were treated from 2004 to 2010 .
median age at surgery was 39 years ( range : 1852 ) . mean lesion size was 1.0 cm2 ( sd : 0.2 ) .
all patients underwent a four - step surgical procedure including synovectomy , debridement and microfractures of the ocl , capsular shrinkage , and bracing and non - weightbearing for 21 days . clinical assessment included objective examination , the aofas ankle and hindfoot scoring system , karlsson - peterson score , tegner activity level , and sefton articular stability scale .
mri scans were taken 18 months after surgery in all patients.resultsfollow-up examination at an average of 4 years ( sd : 1.1 ) after surgery showed significant improvement of all variables compared to pre - operative values ( p < 0.05 ) .
most patients rated their outcome as good / excellent .
mri scans taken 18 months after surgery documented completely repaired lesion in 27 ankles , slight bone marrow oedema with partially repaired defect in 9 patients , and visible defect in 2 ankles.conclusionbased on the present results , we propose a comprehensive four - step protocol as a safe and clinically effective treatment option in patients with post - traumatic ocls of the ankle.level of evidenceretrospective case series , level iv . |
PubmedSumm118706 | ***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 field of gene expression analsysis has evolved dramatically in recent years . with a basis in microarray technology and the ongoing transition into next - generation sequencing technologies ,
the microarray technology provides a way of obtaining huge quantities of genome and transcriptome data ; it has developed from relatively small - scale experiments using in - house platforms and protocols to more robust studies using what are essentially genome - wide commercially manufactured arrays .
today , several commercial and academic platforms exist , with different array manufacturing and sample preparation approaches .
a common criticism of the field of global gene expression analysis has been its lack of standardised experimental protocols and well - defined reference studies comparing different platforms and procedures .
to address these issues , the microarray quality control consortium ( maqc ) performed a study where relative gene expression measurements , using one and two - colour platforms , were compared within and between platforms , as well as with taqman real - time pcr data [ 13 ] .
the reference data set , based on standardised commercially available rna sources , was made publicly available , enabling researchers to benchmark new procedures and platforms .
one overall purpose for developing new protocols for global gene expression analysis is to improve the quality of the results produced . during recent years
the quality of microarrays has been further improved in terms of content and fabrication procedures [ 46 ] , ensuring limited slide - to - slide and batch - to - batch variability .
equally important is sample preparation , during which several of the steps may introduce additional variability into the experiment . to minimise variation within an experiment ,
an experienced technician and a good laboratory protocol are required . in general , the statistical power increases as the variance in the experiment decreases , increasing the likelihood that , for example , differentially expressed genes and subtle differences between samples will be detected . in order to achieve these goals , we present a method where all the major steps in a typical cdna library preparation protocol are automated using a robotic workstation capable of handling superparamagnetic beads .
our procedure performs cdna synthesis , purification and subsequent labelling using nhs - modified fluorophores , and is capable of handling up to 48 samples per instrument in parallel .
studies have indicated that automation of sample preparation for single - colour microarray experiments can reduce variation and increase throughput [ 7 , 8 ] .
we present a similar approach , to benchmark our protocol against the freely available data from maqc to validate our results , and compare the automated approach to our own manual procedure as well as to several academic and commercial platforms .
several methods for the purification of nucleic acids are available today , including ethanol precipitation and spin - column - based methods .
these methods generally require manual input , thereby limiting the throughput of the experiment and increasing variability . in order to reduce human input and increase reproducibility , an automated protocol for cdna synthesis ,
labeling , and purification has been developed using a dedicated instrument capable of handling superparamagnetic beads .
the procedure is outlined in figure 1 , where the two purification steps are highlighted . for a full run of 48 samples ,
the current protocol takes about five hours , with most of the time being incubation steps ( e.g. , cdna synthesis takes two hours ) .
performing 24 similar reactions manually can be done in approximately the same time , but manual handling introduces variation that can be avoided using the automated approach .
the automated protocol outperform the manual procedure when it comes to within - experiment correlation between replicates .
an overview of the automated approach for total rna followed by cdna synthesis and labelling in illustrated in figure 1 .
this procedure consists of several critical steps that were optimised , including evaporation from open wells , investigation of bead capacity , and proper clean - up from free fluorophores . in conclusion , we show that an automated approach for cdna synthesis performs better than a similar manual procedure when interrogated using dna microarrays .
we believe that this conclusion is valid for other readouts platforms as well , including rna - sequencing [ 911 ] . in order to increase the yield from the purification steps
briefly , following the first elution , the beads are returned to the supernatant , enabling capture of any residual cdna .
this approach increases the yield from each purification step by approximately 15% , which has a significant impact on the overall yield of labelled cdna , given that the process makes use of two purification steps ( data not shown ) .
only small amounts of beads are necessary for a high yield : approximately 1.8 g of labelled cdna can be purified using as little as 20 g of beads if there are two captures during each purification step ( figure 2 ) . to facilitate complete capture
, we use 150 l of beads , thus purifying approximately 5 g of labelled cdna .
precipitation is carried out in an ethanol / teg buffer , after which the bead pellet is washed five times in 80% ethanol .
a large number of washes are necessary to remove unincorporated fluorophores , but does not affect the yield of sample cdna ( data not shown ) .
elution can easily be performed in a low salt buffer , such as water . in order to test the performance and reproducibility of the automated process
, we took advantage of the well - documented model system used by the maqc consortium [ 13 ] .
the aim of the macq study was to create a freely - available large reference data set and to compare multiple transcription profiling platforms using a standard set of rna samples .
we chose a subset of these platforms for our analysis . for within - experiment comparisons , the two - colour experiments , nci 3 and 4 ( national cancer institute ) ,
these platforms use the human probe set version 3 from operon , which is also used on the slides in our study .
we used the same sources of rna , total human reference rna ( stratagene ) , and firstchoice human brain reference total rna ( ambion ) to evaluate and compare the automated protocol with the manual procedure for cdna synthesis and labelling prior to microarray analysis .
ten replicates were run in two separate automated experiments and were compared with ten replicates prepared according to the manual procedure .
the differential gene expression between the two sources of rna was measured in these experiments as outlined for the previous macq experiments .
figure 3 shows the overall results by comparing the correlation between the m - values ( log2(sample a / sample b ) ) from our experiments ( kthauto and kthman ) and m - values from different experiments in previous studies [ 2 , 3 ] , including only two - colour platforms .
the samples from our two automated experiments cluster together closely and cluster less closely to the manual samples . within the automated cluster , two samples ( kthauto_b2 and kthauto_a4 )
are set slightly apart from the other samples but are close to each other ; they are still , however , within the same super - cluster ( blue cluster , figure 3(a ) ) . in both of these samples , the cdna synthesis and labelling procedure yielded about two thirds the amount of labelled cdna compared to the other samples ( this was due to manual handling - related issues ) , while the degree of labelling was about the same ( data not shown ) .
this may indicate that the total amount of hybridised material could play an important role in creating reproducible results .
the median spearman correlation of all available m - values between samples labelled using the automated protocol was 0.92 and 0.91 for the two parallel experiments ( kthauto1 and kthauto2 , resp . ) , compared to 0.86 for the manual procedure ( kthman , figure 3(b ) ) indicating an increase in well - to - well reproducibility .
this is in concordance with previous studies [ 7 , 8 ] . in the wider context
, a higher correlation between replicates means greater statistical ability to detect differentially expressed genes .
when comparing the top 200 differentially expressed genes , 175 ( 87.5% ) are common between kthauto1 and kthauto2 , which can be compared to 155 ( 77.5% ) between nci3 and nci4 ( supplementary figures 1(a ) and 1(b ) in supplementary material available online at doi:10.1155/2009/396808 ) . in the maqc study ,
after mapping the probes to refseq and aceview , a complete list of 12091 probes for each platform was created , representing 12091 refseq entries in 12091 entrez genes [ 3 , 14 ] .
after filtering out genes with stable expression levels across all experiments ( see section 2 ) , we used this list to calculate the spearman 's rank correlation coefficient between mean m - values from each experiment . when compared to other platforms investigated in the maqc project , the data generated using the automated approach cluster together with the two - colour arrays used by nci .
this is to be expected since , as aforementioned , both nci and the arrays used in the automation experiments made use of the human probe set version 3 from operon . as expected from previous studies , all one - colour platforms
( ge healthcare , applied biosystems , agilent one - colour , illumina , and affymetrix , see for more information on these platforms ) cluster together ( figure 4 ) . when comparing the spearman correlation values , the correlation between the kth auto experiments is 0.97 , whereas the highest correlation between the different experiments performed by nci is 0.94 .
a higher correlation between experiments ( lower technical noise ) means that samples can be added later , while introducing relatively little variability to the data .
here , we chose to take advantage of an efficient in - tip magnetic separation system [ 15 , 16 ] to assess throughput and variance within a gene expression experiment .
there are several approaches available for nucleic acid purification using paramagnetic beads ; these include the use of streptavidin - coated beads and a biotinylated primer in the reverse transcription step .
however , unless strictly controlled , free biotinylated primers or free biotinylated nucleotides can rapidly saturate the beads , leading to a low purification yield . here
we show that , by precipitating the first - strand cdna on carboxylic acid coated paramagnetic beads , a high yield can be achieved in the purification steps , giving a large quantity of purified product . using this automated procedure ,
thus , automation of cdna library preparation for analysis on microarrays or using massive - scale sequencing [ 911 ] leads to decreased variance and greater statistical power to detect for example differentially expresssed genes or alternative splicing patterns .
we describe an automated platform that can be used to increase the robustness of the overall performance of cdna library preparation , including target labelling .
the maqc study indicated two types of variation : array content and array performance , the latter relating to the manual variation associated with performing the experiments .
we show that this variation can be minimised by using an automated procedure , employing a standard microtiter plate .
the number of samples that can be run in parallel can also be increased using this protocol from one up to 48 .
a single row in the microtiter plate ( 1 to 12 samples ) takes approximately 4 hours and 40 minutes and the time increase for running four rows ( 48 samples ) is marginal . some modifications , other than changing the purification method , were necessary when automating the process .
these were mainly due to reactions associated with the microtiter wells , which have no lids , so that evaporation occurs and is pronounced at elevated temperatures .
the amount of evaporated water at a given temperature , however , is relatively constant . during the initial total rna denaturing step , about 3.5 l of water evaporates , and this
prior to optimisation , the amount of cdna obtained from the first strand synthesis on the workstation was approximately 20% less than from synthesis in closed tubes .
this effect was completely eradicated when water was added at regular intervals during the cdna synthesis ( data not shown ) .
the adjusted volume of the samples was determined empirically . to investigate the performance of our automated procedure , we chose dna microarrays because of the access to a well established reference set of rna samples and the standardized statistical procedure to address and demonstrate technical variation .
in general , well - to - well correlation increased when compared to a manual protocol .
correlation between different experiments ( i.e. , the same experiment performed at different days ) , we noted a higher correlation using our automated procedure when compared to the procedure carried out by nci .
our results indicate that automation of sample preparation improves technical reproducibility , and should be general indifferent of the platform for readout , dna microarrays or rna - sequencing .
in all experiments , total human reference rna ( stratagene ) ( sample a ) and firstchoice human brain reference total rna ( ambion ) ( sample b ) were used .
the two rna samples were labelled as described below , and subsequently hybridised to microarrays . in each experiment , a total of 10 microarrays was used . on five of these , sample a labelled with cy3 and sample b labeled with cy5 were hybridised . on the remaining five slides ,
the dye setting was reversed , giving a dye - balanced direct design , corresponding to the two - colour microarray experiments that were carried out within the maqc study . using the optimised protocol , we performed two experiments following the automated approach and one following our manual procedure .
for the automated sample preparation , the process from total rna to purified labelled cdna was performed on a magnatrix 1200 ( magnetic biosolutions , sweden ) robotic workstation .
this workstation is equipped with a heating block and a system for in - tip magnetic separation . for initial cooling in the instrument
the protocol takes approximately 4 hours and 40 minutes for a single microtiter row of 12 samples , and only slightly longer for the double amount of samples .
twenty micrograms of total rna was primed with 5 g of random hexamers ( invitrogen , usa ) in a total volume of 22 l depc - treated sterile deionised water .
after denaturing the rna for 10 minutes at 70c , the mixture was cooled in a pcr - cooler ( eppendorf ) in the instrument , maintaining 0c in the wells for 5 minutes prior to starting the first strand cdna synthesis .
after this step , approximately 3.5 l of liquid had evaporated , resulting in a total volume of about 18.5 l .
a volume of 11.5 l of a reverse transcription master mix was then added , setting the reaction composition to 1x first - strand buffer ( invitrogen ) , 0.01 mm dtt ( invitrogen ) , 0.4 mm aminoally l - modified dutp ( biotium ) , 0.1 mm dttp ( sigma - aldrich ) , 0.5 mm datp , dctp , and dgtp ( sigma - aldrich ) and 400 units of superscript iii reverse transcriptase ( invitrogen ) . an initial incubation of 10 minutes at room temperature ( approximately 22c ) was followed by two hours at 46c . during the incubation , 2.5 l depc - treated sterile deionised water was added every 15 minutes to compensate for evaporation .
the cdna synthesis reaction was stopped by the addition of 3 l 0.2 m edta after which rna was hydrolysed by the addition of 5 l 1 m naoh together with incubation at 70c for 15 minutes .
ph neutralisation was achieved by the addition of 15 l 1 m hepes , ph 7.0 , after the hydrolysis step .
prior to purification , the storage buffer was removed from 150 g of dynabeads myone carboxylic acid ( invitrogen ) by magnetic separation .
the beads were resuspended in the neutralised cdna synthesis mixture , after which three volumes ( 150 l ) of binding buffer , containing 80% ethanol and 6.7% teg , were added . after a single 10-minute incubation at room temperature ,
the beads were collected from the supernatant and washed five times in 45 l 80% ethanol .
elution was carried out by resuspending the beads in 10 l sterile deionised water and mixing for 1 minute . to increase the yield , collected beads were resuspended in 5 l of sterile deionised water and returned to the supernatant for a second capture .
the incubation , washing and elution steps were then repeated as described above , resulting in a final volume of 20 l . in order to set the ph to facilitate coupling to fluorophores , 2 l 1 m nahco3 , ph 9.0 , was added to the eluted cdna , after which the mixture was transferred to a 5 l aliquot containing one tenth of the contents of mono - functional nhs - ester cy3 or cy5 dye tubes ( ge healthcare ) dissolved in dmso ( sigma - aldrich ) . after a single 30-minute incubation at room temperature , 2 l of 1 m hepes , ph 7.0 ,
was added to neutralise the mixture prior to purification of fluorophore - coupled cdna using carboxylic acid coated paramagnetic beads as described above .
briefly , the pre - cdna synthesis incubation was performed at 25c instead of room temperature , and the purification steps were carried out using the minelute cleanup system ( qiagen ) according to the manufacturer 's recommendations .
differences include changing the recommended washing buffer before labelling the cdna to 80% ethanol and the elution buffer to sterile deionised water .
moreover , the neutralisation step was carried out using 5 l 1 m hcl .
the arrays used were provided by the kth microarray center ( http://www.ktharray.se/ ) , and consisted of the human genome oligo set version 3.0 ( operon ) printed in 30% dmso onto ultragaps slides ( corning ) .
after printing , the slides were uv cross - linked at 150 mj / cm .
the slides were prehybridised for 30 minutes at 42c in a prehybridisation solution consisting of 5x ssc , 0.1% sds ( sigma - aldrich ) and 1% bsa ( sigma - aldrich ) to avoid unspecific hybridisation to the glass surface .
the slides were subsequently washed in water and isopropanol ( sigma - aldrich ) and dried using a slide centrifuge .
the two samples were dye - balanced to make sure that equal amounts of dye were hybridised in each channel , then they were pooled and denatured ( 3 minutes at 95c ) in a hybridisation mixture containing 50% formamide ( sigma - aldrich ) , 5x ssc and 0.1% sds ( sigma - aldrich ) , 20 g human cot-1 dna ( invitrogen ) , and 20 g yeast trna ( invitrogen ) .
the 65-l hybridisation mixture was then cooled on ice for 1 minute and applied under a cover slip ( erie scientific company ) , placed on top of the printed array ; it was then hybridised for 24 hours at 42c in a water bath .
following hybridisation , the slides were washed with increasing stringency using 2x ssc and 0.1% sds at 42c , followed by 0.1x ssc and 0.1% sds at room temperature and finally by five repeated washes with 0.1x ssc at room temperature .
the arrays were scanned at 10-m resolution using an agilent g2565ba scanner ( agilent technologies , usa ) , with the photo multiplier tube set to 100% for each laser .
the images thus acquired were analysed using the irregular gridding algorithm in genepix pro 5.1 ( axon ) and the resulting data were imported into the r environment for statistical computing and visualisation .
the raw data were extracted from the median foreground intensity for both channels and subsequently filtered on the basis of flags ( features either not found by the image software , or marked as bad spots ) , a low signal compared to the local background and saturated signals .
data normalisation was carried out using a block - wise lowess approach , included in the aroma package and a per - feature mean log2-ratio ( m - value ) across all slides was calculated using the limma software package .
the data was compared with relevant parts of the maqc data set , using clustering and correlation analysis tools in the kth software package .
mean fold change and p - values for each platform were calculated , and all contrasts set up between all platforms using the limma software package .
the files containing raw data were made publicly available in the arrayexpress repository , with experiment number e - tabm-749 .
for intraplatform comparisons , a subset of platforms with the same probe set ( operon human probe set version 3 ) and experimental design from maqc was used .
features were mapped using the oligonucleotide i d , which is a unique identifier for each oligonucleotide sequence . for interplatform comparisons ,
the m - values for 12091 genes common to the platforms were extracted , as well as a subset of 906 genes with available taqman real - time pcr - data ; these were compared to all the microarray platforms within maqc .
genes for which the interquartile range was lower than 0.5 were removed from the analysis , in order to reduce background noise from genes with stable expressions levels across all tested platforms .
in addition to hybridising the labelled cdna samples to microarrays , the binding capacity of the carboxylic acid - coated paramagnetic beads was measured .
the number of washes after binding the cdna was optimised , after which elution was carried out and cdna and fluorophore concentrations were determined using a nanodrop nd-1000 instrument ( nanodrop ) .
Output:
| background .
several technologies , such as in - depth sequencing and microarrays , enable large - scale interrogation of genomes and transcriptomes . in this study , we asses reproducibility and throughput by moving all laboratory procedures to a robotic workstation , capable of handling superparamagnetic beads .
here , we describe a fully automated procedure for cdna synthesis and labelling for microarrays , where the purification steps prior to and after labelling are based on precipitation of dna on carboxylic acid - coated paramagnetic beads .
results .
the fully automated procedure allows for samples arrayed on a microtiter plate to be processed in parallel without manual intervention and ensuring high reproducibility .
we compare our results to a manual sample preparation procedure and , in addition , use a comprehensive reference dataset to show that the protocol described performs better than similar manual procedures . conclusions .
we demonstrate , in an automated gene expression microarray experiment , a reduced variance between replicates , resulting in an increase in the statistical power to detect differentially expressed genes , thus allowing smaller differences between samples to be identified .
this protocol can with minor modifications be used to create cdna libraries for other applications such as in - depth analysis using next - generation sequencing technologies . |
PubmedSumm118707 | ***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 rapidly changing lifestyles of our present times , the use of synthetic chemicals , chemotherapeutic agents , and carcinogenic substances , as well as the widespread environmental pollutants , have negatively impacted human and other living organisms at the cellular and genetic levels .
this is all the more dangerous because dna genome sequence , carrying the genetic code , replicates semi - conservatively , handing down this tainted biological heritage from one generation to the next ( 1 ) .
the dna molecule is continuously targeted by numerous carcinogenic and mutagenic agents that induce , either directly or indirectly , the production of free radicles , which react with each and every component of the dna molecule , damaging its purine and pyrimidine bases ( 2 , 3 ) .
free radicals are primarily generated as a result of various metabolic processes and are generally regarded as essential for molecular organization processes .
however , carcinogenic and mutagenic agents to which the human is continuously exposed leads to accumulation of free radicals in the body , compromising the ability of the biological system to remove toxins and repair the damage they cause , hence the oxidative phenomenon , which plays a major role in the development of many diseases ( 46 ) .
natural products also have been known since the most ancient ages for their therapeutic values due to their varied chemical content , which helps preserve and develop self - defense mechanisms , represented by the natural cellular resistance , which protects the cells from toxic products and other environmental stresses .
many studies have indicated the usability of naturally occurring chemical substances as effective antioxidants that improve human health and protect against cancer and heart diseases .
it is noteworthy here that antioxidants are both anti - mutagenic , i.e. , protect against potential nucleic acid damage and anti - carcinogenic , i.e. , prevent the development of secondary tumors without interfering with the therapeutic action of chemotherapeutic agents , whose efficacy it actually potentiates ( 4 , 711 ) .
evidence abounds as to the advisability of combining antioxidants with certain types of chemotherapeutic agents , due to their effectiveness in reducing neoplastic toxicity and limiting the generation of free radicals resulting from chemotherapy ( 12 ) .
allah has created a multitude of natural products that may reduce the genetic toxicity associated with chemotherapy or caused by mutagenic agents , and it is a human duty to see how natural products can become a promising source of new medicines .
god almighty has spoken the truth when he said in his holy book : then eat all the fruits and follow the ways of your lord laid down [ for you ] .
there emerges from their bellies a drink , varying in colors , in which there is healing for people . indeed , in that is a sign for a people who give thought [ sura an - nahl , verse 69 ] . out of the verse , this study aspires to demonstrate the scientific miracles in the divine power healing that god placed in bee products ( propolis ) and what lies in the diversity of compounds contained in the perfect consistency between effective in its material and its effectiveness , which may occur from the effects on cells physical transaction result from dacarbazine ( dtic ) as anti - cancer drugs .
this experimental in vivo study was conducted on male albino mice ( mus musculus , 2n = 40 ) of the mfi strain , aged 1012 weeks , which have been obtained from the animal house of the king fahd medical center located at king abdulaziz university in jeddah , where he developed these mice in special plastic cages under appropriate laboratory conditions in a well - ventilated private room .
the water is provided daily along with fed dry rations in order to maintain the animal experiments .
dacarbazine is chemotherapy used in cancer patients ; its trade name is known as deticene , obtained from king abdulaziz hospital in jeddah .
bee glue , a material collected by bees from leaves buds and has numerous benefits , and was obtained from wild honey company in saudi arabia , riyadh .
eighteen male mice were used in this study , which were divided into four main groups as follows : 1 ) group 1 was treated with a distilled water ; 2 ) group 2 was treated with a 50mg / kg dose of bee glue ( propolis ) ( 13 ) ; and 3 ) group 3 was treated with a 3.5mg / kg dose of dacarbazine , adjusted for mice in accordance with the international adjusted dosage schedule ( 14 ) ; 4 ) group 4 was treated with a combination of propolis at a dose of 50mg / kg and dacarbazine at a dose of 3.5mg / kg .
groups were further categorized into three categories as follows : category a ) : receiving sequentially combined treatment with propolis then 2h dacarbazine category b ) : receiving simultaneous treatment with propolis and dacarbazine category c ) : receiving sequentially combined treatment with dacarbazine then 2h propolis dacarbazine was administered by intraperitoneal injection ( i.p . )
the technique suggested by heddle ( 17 ) was followed in preparing bone marrow slices for the micronuclear test ( figure 1 ) . to calculate the preventive effect , i.e. , anti - mutagenic effect of propolis against the mutagenic effect of dacarbazine , the serpeloni et al .
statistical analysis was conducted on the basis of independent - samples t - test and analysis of variance ( anova ) to calculate the significance of findings arrived at through the test under study .
this experimental in vivo study was conducted on male albino mice ( mus musculus , 2n = 40 ) of the mfi strain , aged 1012 weeks , which have been obtained from the animal house of the king fahd medical center located at king abdulaziz university in jeddah , where he developed these mice in special plastic cages under appropriate laboratory conditions in a well - ventilated private room .
the water is provided daily along with fed dry rations in order to maintain the animal experiments .
dacarbazine is chemotherapy used in cancer patients ; its trade name is known as deticene , obtained from king abdulaziz hospital in jeddah .
bee glue , a material collected by bees from leaves buds and has numerous benefits , and was obtained from wild honey company in saudi arabia , riyadh .
eighteen male mice were used in this study , which were divided into four main groups as follows : 1 ) group 1 was treated with a distilled water ; 2 ) group 2 was treated with a 50mg / kg dose of bee glue ( propolis ) ( 13 ) ; and 3 ) group 3 was treated with a 3.5mg / kg dose of dacarbazine , adjusted for mice in accordance with the international adjusted dosage schedule ( 14 ) ; 4 ) group 4 was treated with a combination of propolis at a dose of 50mg / kg and dacarbazine at a dose of 3.5mg / kg .
groups were further categorized into three categories as follows : category a ) : receiving sequentially combined treatment with propolis then 2h dacarbazine category b ) : receiving simultaneous treatment with propolis and dacarbazine category c ) : receiving sequentially combined treatment with dacarbazine then 2h propolis
the technique suggested by heddle ( 17 ) was followed in preparing bone marrow slices for the micronuclear test ( figure 1 ) . to calculate the preventive effect , i.e. , anti - mutagenic effect of propolis against the mutagenic effect of dacarbazine , the serpeloni et al .
statistical analysis was conducted on the basis of independent - samples t - test and analysis of variance ( anova ) to calculate the significance of findings arrived at through the test under study .
results obtained 24 hours after the last treatment of male mice with a 50 mg / kg dose of propolis ( table 1 ) showed that the number of micronuclei was slightly less than the control sample , valued at 5.670.88 ( 0.57% ) .
however , there were no significant differences in the mean appearance of micronucleated polychromatic erythrocytes ( mn - pces ) , compared with the control sample s value of 6.001.53 ( 0.60% ) ( table 2 , figure 1 and 2 ) .
results obtained from table 2 indicate dacarbazine s high cytotoxicity to bone marrow cells of male mice treated with a 3.5 mg / kg therapeutic dose of dacarbazine .
such treatment showed a highly significant increase ( p<0.001 ) in the mean appearance of micronucleated polychromatic erythrocytes ( mn - pces ) , valued at ( 64.672.73 ) , estimated at ( 6.47% ) , compared with the control sample ( figure 2 ) .
examination of micronucleated polychromatic erythrocytes ( mn - pces ) of bone marrow cells of mice under sub - acute , combined treatment with a 50mg / kg dose of propolis and a 3.5 mg / kg therapeutic dose of dacarbazine .
precedent , simultaneous , and subsequent sub - acute treatment showed a highly significant increase ( p<0.001 ) in the mean appearance of micronucleated polychromatic erythrocytes ( mn - pces ) , valued at ( 12.672.03 ) , 29.332.85 , and 39.332.60 , estimated at 1.27% , ( 2.93% ) and 3.93% respectively , compared with 64.672.73 , estimated at 6.47% resulting from sub - acute treatment with dacarbazine at therapeutic dose of 3.5mg / kg . calculation of the anti - mutagenic impact on the inducer of nucleoli revealed that precedent , simultaneous , and subsequent sub - acute combined treatment with both propolis and dacarbazine had caused a marked improvement , valued at 80.37% , 54.71% , and 39.26% , respectively ( table 2 , figure 3 ) .
results obtained from anova indicate a highly significant increase ( p<0.001 ) in the mean appearance of micronucleated polychromatic erythrocytes ( mn - pces ) , valued at ( f=108.60 ) between sub - acute treatment with either 50mg / kg dose of propolis or 3.5 mg / kg therapeutic dose of dacarbazine , on the one hand , and the impact of combined , sub - acute treatment with both propolis and dacarbazine , compared with the control sample ( table 3 ) . a comparison test ,
using the least significant difference , showed the highest significant difference to be ( p<0.001 ) in the mean appearance of micronucleated polychromatic erythrocytes ( mn - pces ) , as a result of sub - acute treatment with dacarbazine therapeutic dose and the simultaneous , and subsequence combined treatment with both propolis and dacarbazine and to be ( p<0.05 ) , as a result of combined , sub - acute , precedent treatment with propolis and subsequent treatment with the chemotherapeutic agent . on the other hand , treatment with either propolis did not post any significant difference in the mean appearance of micronucleated polychromatic erythrocytes ( mn - pces ) ( figure 4 ) .
treatments , in terms of least impact on the inducer of nucleoli , can thus be placed in the following order : p < t2a < t3a < t4a < t1a .
results obtained 24 hours after the last treatment of male mice with a 50 mg / kg dose of propolis ( table 1 ) showed that the number of micronuclei was slightly less than the control sample , valued at 5.670.88 ( 0.57% ) .
however , there were no significant differences in the mean appearance of micronucleated polychromatic erythrocytes ( mn - pces ) , compared with the control sample s value of 6.001.53 ( 0.60% ) ( table 2 , figure 1 and 2 ) .
results obtained from table 2 indicate dacarbazine s high cytotoxicity to bone marrow cells of male mice treated with a 3.5 mg / kg therapeutic dose of dacarbazine .
such treatment showed a highly significant increase ( p<0.001 ) in the mean appearance of micronucleated polychromatic erythrocytes ( mn - pces ) , valued at ( 64.672.73 ) , estimated at ( 6.47% ) , compared with the control sample ( figure 2 ) .
examination of micronucleated polychromatic erythrocytes ( mn - pces ) of bone marrow cells of mice under sub - acute , combined treatment with a 50mg / kg dose of propolis and a 3.5 mg / kg therapeutic dose of dacarbazine .
precedent , simultaneous , and subsequent sub - acute treatment showed a highly significant increase ( p<0.001 ) in the mean appearance of micronucleated polychromatic erythrocytes ( mn - pces ) , valued at ( 12.672.03 ) , 29.332.85 , and 39.332.60 , estimated at 1.27% , ( 2.93% ) and 3.93% respectively , compared with 64.672.73 , estimated at 6.47% resulting from sub - acute treatment with dacarbazine at therapeutic dose of 3.5mg / kg . calculation of the anti - mutagenic impact on the inducer of nucleoli revealed that precedent , simultaneous , and subsequent sub - acute combined treatment with both propolis and dacarbazine had caused a marked improvement , valued at 80.37% , 54.71% , and 39.26% , respectively ( table 2 , figure 3 ) .
results obtained from anova indicate a highly significant increase ( p<0.001 ) in the mean appearance of micronucleated polychromatic erythrocytes ( mn - pces ) , valued at ( f=108.60 ) between sub - acute treatment with either 50mg / kg dose of propolis or 3.5 mg / kg therapeutic dose of dacarbazine , on the one hand , and the impact of combined , sub - acute treatment with both propolis and dacarbazine , compared with the control sample ( table 3 ) .
a comparison test , using the least significant difference , showed the highest significant difference to be ( p<0.001 ) in the mean appearance of micronucleated polychromatic erythrocytes ( mn - pces ) , as a result of sub - acute treatment with dacarbazine therapeutic dose and the simultaneous , and subsequence combined treatment with both propolis and dacarbazine and to be ( p<0.05 ) , as a result of combined , sub - acute , precedent treatment with propolis and subsequent treatment with the chemotherapeutic agent . on the other hand , treatment with either propolis did not post any significant difference in the mean appearance of micronucleated polychromatic erythrocytes ( mn - pces ) ( figure 4 ) .
treatments , in terms of least impact on the inducer of nucleoli , can thus be placed in the following order : p < t2a < t3a < t4a < t1a .
this study aimed at evaluating the potential genetic , cellular , and preventive impact of treatment with propolis per se , combined , precedent , simultaneous , and subsequent treatment with propolis and dacarbazine and treatment with dacarbazine per se . to achieve this goal ,
mfi albino mice of the species mus musculus , being mammals , were chosen , and a therapeutic dose of 3.5mg / kg was also chosen for chemotherapeutic treatment of 8-week - old male mice for five consecutive days .
results of the micronuclear test showed a highly significant ability of dacarbazine to produce micronucleated polychromatic erythrocytes ( mn - pces ) in bone marrow cells of mice treated with a therapeutic dose of dacarbazine , compared with the control sample .
this is consistent with results arrived at by many previous researchers , who treated bone marrow cells using members of the group of alkylating anticancer drugs of which the drug under study , dacarbazine , is also a member ( 1922 ) .
micronuclei originate from acentric chromatid or chromosomal splinters or from whole chromosomes that do not join the nucleus proper at the end of the final phase of cell division ( telophase ) , due to a failure of proper connection to spindle fibers during the anaphase of cell division .
these chromosomes or chromosomal splinters are joined together by means of a nuclear membrane and are small in size , compared with the size of the nucleus proper ( 23 ) .
because micronuclei result from whole or splintered chromosomes joining together during the anaphase of cell division and are connected , as well , to the appearance and development of many types of tumors and negative cell division , they are usually used as biologic indicators of chromosomal aberrations or genetic mutations resulting from chemotherapeutic treatment and are ranked as the first tool to test the ability of chemical substances / chemotherapeutic agents to induce chromosomal anomalies / damage , whether numerical or structural ( 2426 ) , the micronuclear test being the most sensitive and the most powerful statistical tool to evaluate dna breaks , which indicate potential mutations ( 27 ) .
micronuclei form as a result of treatment with antineoplastic drugs that either cause direct damage to the nucleic acid or inhibit the cell cycle or damage the spindle fibers of mitotic division ( 28 ) .
it was observed in previous studies that treatment with dacarbazine had caused chromosomal aberrations / anomalies , chromosomal separation and chromatids gaps ( 29 ) , dna breaks in lymphocytes of patients undergoing dacarbazine chemotherapy ( 30 ) , and a considerable increase in micronuclei , which is considered as an indicator of genetic toxicity exerted by this drug on lymphocytes ( 31 ) .
in addition to those two mechanisms , micronuclei may form as a result of breaks in anaphasic bridges and may itself be the cause of development of bi - centric chromatids , interference of annular chromosomes , or union of sister chromatids ( 28 ) .
it was further proven that treatment of mice with the alkylating agent dacarbazine at a dose of 30mg / kg body weight led to depression and chromosomal anomalies , mostly in the form of chromatid gaps and breaks that are directly proportional to the dosage and duration of the chemotherapeutic agent ( 29 ) . in 2002 , adler et al . conducted a test to determine dacarbazine clastogenic impact on somatic cells , as well as on microbial cells in mice ( 32 ) .
the test showed that dacarbazine - induced production of micronuclei in bone marrow cells , increasing progressively in proportion to the dose of the chemotherapeutic agent , ranging from 0125mg / kg .
dacarbazine is also considered as a powerful oxidizing agent , as dacarbazine - based chemotherapy leads to a release of free radicals , including types of reactive oxygen such as hydrogen peroxide , free hydroxyl radicals [ oh ] , known for its ability to destroy nucleic acids , and other vital cellular molecules ( 34 , 35 ) .
chemotherapy also reduces levels of antioxidant substances and enzymes in various tissues ( 7 ) . by reducing antioxidants , which eliminate cytotoxicity induced by chemicals , including chemotherapeutic agents , by acting as free radical scavenging traps , treatment with dacarbazine results in a deficient cellular defensive mechanism and increased oxidation processes , releasing free radicals , which are known for their ability to destroy cells and ultimately tissues
the appearance of micronuclei in bone marrow cells of mice treated with a therapeutic dose of dacarbazine , as evidenced by the current study , is , therefore , a credible proof of the genotoxic effects of this drug and an indicator of its mutagenicity . combined , precedent , simultaneous , and subsequent treatment with propolis and dacarbazine caused a highly significant reduction in the numbers of micronuclei in micronucleated polychromatic erythrocytes ( mn - pces ) by1.27% , 2.93% , and 3.93% , respectively .
this result is consistent with findings of previous studies that suggested the possibility of prevention of genotoxic effects resulting from chemotherapy , by using compounds that possess antioxidant properties , in vivo and in vitro .
another study was conducted to evaluate both in vivo and in vitro anti - mutagenicity of propolis in mice treated in vitro with propolis in combination with daunomycin ( dmc ) and 2-aminofluorene ( 2af ) and in vivo with propolis in combination with mitomycin ( mmc ) and cyclophosphamide ( cp ) , all of which are known to lead to the formation of micronuclei in bone marrow cells of mice as well as to the development of chromosomal aberrations .
results showed that propolis prevents the development of mutations as a consequence of treatment with ( dmc ) and ( 2af ) and that such prevention is directly dependent on dosage because propolis was observed to prevent the formation of micronuclei at concentrations ranging from 45135 mg / kg and to reduce the rate of recurrence of chromosomal aberrations at 135mg / kg concentration . from those findings
, we can safely conclude that propolis is a good inhibitor of mutations resulting from in vitro treatment with ( dmc ) and ( 2af ) , as well as in vivo treatment with cp and mmc ( 36 ) .
the results of the preventive effects study of different concentrations of propolis against genotoxicity resulting from the treatment aflatoxin b1 ( afb1 ) in mice through the micronuclei test to increase the production of micronuclei in peripheral lymphocytes , treatment with propolis decreased genotoxicity indicators that it causes by afb1 , which is attributed to the strong ability of propolis to eliminate free radicals ( 37 ) . upon using hydrogen peroxide to induce damage to lymphocytic nucleic acid in order to evaluate the preventive or protective potential of propolis , a marked reduction in hydrogen - peroxide - induced nucleic acid damage
this may be attributable to the antioxidant activity of phenolic compounds contained in propolis , which contributes to the limitation of nucleic acid damage resulting from hydrogen peroxide .
propolis has , therefore , a protective chemical activity , which may occur under various mechanisms ( 38 ) .
this study , thus , demonstrates that dacarbazine has a genotoxic and mutagenic impact and contributes to chromosomal breakage , as was shown by the micronuclear test .
results obtained from this test indicate that sub - acute , combined , precedent , simultaneous , and subsequent treatment with propolis and dacarbazine limited the cytotoxic and genotoxic impact of sub - acute treatment with dacarbazine per se .
this study suggests , therefore , based on the previous findings , that the ability of propolis to limit dacarbazine cytotoxic and genotoxic effects may be attributable to propolis being a potent antioxidant ( 39 ) .
propolis antioxidant and anticancer activity may be linked to the antioxidant property of its individual active components ( 39 , 40 ) such as : 1 ) group of vitamins of which the most important are vitamins b1 , b2 , b6 , c , and e. previous research attributed the anticancer activity of these substances as well as its ability to limit the cytotoxic and genotoxic effects of chemotherapy to the following mechanisms : inhibition of estrogen receptors , induction of expression and activation of receptors of peroxide , which prevents cellular proliferation and inhibits nuclear receptors and which induce cellular growth and proliferation ; induction of replicating agents , organizing antioxidation and detoxification , anti - inflammatory activities ; induction of programmed cell death ( apoptosis ) ; enhancement of self - cellular phagocytosis and collagen production ; enhancement of detoxification by p450 cytochrome ; reduction of neoplastic genes ; scavenger of free radicals ; enhancement of the immune system function ( 4143 ) ; 2 ) flavonoids are a group of naturally occurring , low - molecular - weight substances , which possess many beneficial biological effects , including an anti - inflammatory , anti - allergic , antiviral , antioxidant , and anticancer effect , in addition to biologically protective effects , both in vivo and in vitro . the most important members of this group are quercetin , chrysin , caffeic acid phenethyl ester ( cape ) , naringenin , glangin , acaacetin , apigenin , artepilin c. previous studies proved that flavonoids antioxidant impact is much more potent than that of vitamins c and e and that these compounds can prevent damage inflicted by free radicals via several mechanisms , namely , removal of reactive oxygen species ros , activation of antioxidant enzymes , metal chelating activity , reduction of alpha - tocopherol radicals , inhibition of oxidases , alleviation of oxidative stress resulting from treatment with mutagenic agents , augmentation of antioxidant properties of low molecular antioxidants , reduction of p53 protein mutations , arresting cancer cell cycle , inhibition of tyrosine kinase , binding to estrogen receptors , inhibition of ros proteins ( 44 , 45 ) .
the sincerity of the messenger of allah , peace is upon him when he said : the whole hand such believer like bee ate good and put a good signed did not break and did not spoil .
Output:
| objectivethis study was carried out to investigate the ability of propolis to ameliorate the adverse cytogenetic effects of dacarbazine on bone marrow cellsmethodsin this experimental in vivo study , 18 mice were used , divided into four groups : control group ; propolis - treated group ( treated with 50mg / kg propolis ) ; and dacarbazine - treated group ( treated with 3.5mg / kg dacarbazine ) .
the fourth , fifth , and sixth were treated with dacarbazine and propolis as pre 2h , post 2h , and concomitant treatment .
after five days , the bone marrow ( bm ) samples were obtained for cytogenetic investigation.resultsthe in vivo studies revealed that dacarbazine induced an abnormalities in polychromatic erythrocytes cells ( pecs ) as increase of cell with micronuclei , while the dual treatment accompanied with improvement of this abnormalities.conclusionsit could be concluded that there are protective effects of propolis against the adverse effects of dacarbazine .
it could be recommended to use propolis as an adjuvant with chemotherapeutic agents . |
PubmedSumm118708 | ***TASK***
the task is to summarize an input biomedical literature in six sentences
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the input is a biomedical literature
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the output is the summary of an input biomedical literature in six sentences
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Input: genital c. trachomatis infections have emerged as the most prevalent sexually transmitted diseases of bacterial origin . in women ,
the infection usually manifests as urethritis , cervicitis , salpingitis , and endometritis though a large proportion of the women remain asymptomatic .
if untreated , complications and sequelae such as pelvic inflammatory disease ( pid ) , ectopic pregnancy and tubal infertility , and still birth with important socioeconomic consequences are common
. to initiate early and appropriate therapy , definitive laboratory diagnosis should be available to the physicians as soon as possible .
the physicians should also be aware of the prevalence of infection in their patients to arrive at a quick presumptive diagnosis , since most of the patients remain asymptomatic .
previous studies from different parts of the world , documented that 1233% of women attending std clinics and the gynecologist 's clinics with cervicitis harbored chlamydia in their cervices [ 46 ] . in india
the prevalence reported from a small study was 10.5% in women in the age group of 2030 years in southern india in 2009 .
an earlier single point study in 1993 from new delhi , india reported that 41% of women with vaginal discharge ( cervicitis ) and 36% of women with infertility were c. trachomatis positive . however
no long - term study spanning several years regarding c. trachomatis involvement in female genital infections has been reported from india .
c. trachomatis consists of 18 serovars , a - k , l1-l3 , da , ia , and l2a ; serovars d - k and l1-l3 are implicated in genital infections .
determination of causative c. trachomatis serovar by conventional methods is cumbersome and usually difficult as the serovar - specific antibodies are not commercially available . the polymerase chain reaction ( pcr ) assay along with restriction fragment length polymorphism ( rflp ) analysis of the major outer membrane protein ( momp ) coding gene was successfully used for genotyping of c. trachomatis from clinical specimens [ 9 , 10 ] .
scanty information is available regarding the prevalent serovars or genotypes of c. trachomatis causing infections from india .
we are regularly testing for the presence of c. trachomatis infection in women of child - bearing age coming to the gyneaecology clinic of our hospital for the last 16 years .
furthermore , we genotyped few of the c. trachomatis from cervical specimens using rflp pattern analysis of the major outer membrane protein ( momp ) coding gene of c. trachomatis amplified by pcr assay .
from 1994 to 2010 , a total of 2466 women in the age group of 2050 years clinically suspected of having c. trachomatis - related infections and attending the obstetrics and gynecology clinic of all india institute of medical sciences , new delhi , were included in this study . these comprised of 436 cases of cervicitis , 1671 cases of infertility , 44 cases of pelvic inflammatory disease ( pid ) , and 315 cases with adverse pregnancy outcomes ( boh ) . after informed consent ,
endocervical swabs were collected using a sterile cotton wool swab from the endocervical canal by rotating the swab vigorously for 1630 seconds .
three separate swabs were collected randomly ; one was smeared onto the well of a teflon - coated glass slide for direct fluorescent antibody ( dfa ) test , and the other two were placed in vials containing 0.2 m sucrose phosphate buffer ( 0.2 msp ) medium and transported to the laboratory on ice immediately for pcr assay and tissue culture isolation .
chlamydia trachomatis direct specimen kit ( microtrak , usa ) was used for the purpose according to the manufacturer 's instructions as described before [ 11 , 12 ] .
briefly , the smears were fixed with cold methanol and stained with fluorescent tagged anti - chlamydia monoclonal antibody ( syva microtrack , usa ) for 30 minutes at 37c in a humid chamber .
the slides were washed with phosphate buffer saline for 10 minutes followed by double distilled water for 5 minutes , air - dried , mounted , and observed under the fluorescent microscope ( nikon , japan ) .
the positive and negative control sides provided by the manufacturers ( syva microtrack , usa ) were included in each batch of the test .
the endocervical swabs collected in 0.2 msp buffer were inoculated onto mitomycin - c - treated confluent monolayers of mccoy cells grown on cover slips in shell vials via centrifugation at 2000 rpm , according to the method described previously .
the cover slips were taken out , washed with pbs and stained with fitc tagged anti - chalmydia monoclonal antibodies according to manufacturer 's instructions using chlamydia trachomatis culture confirmation test kit ( microtrak , usa ) .
the cover slips were mounted and observed under the fluorescent microscope ( nikon , japan ) for c. trachomatis inclusions in mc coy cells .
appropriate positive control { c. trachomatis l2 434 bu strain } and negative control ( 0.2 msp buffer ) were included in each batch of the test .
an in - house conventional pcr assay for amplification of a 517 bp region of c. trachomatis cryptic plasmid was used in 333 endocervical specimens from patients with cervicitis using a set of published primers , as per the method used by us previously .
dna extracted from c. trachomatis l2 ( 434 bu strain ) grown in the yolk sac of embryonated hen 's egg and purified by renograffin gradient centrifugation was used as positive control and distilled water was used as negative control .
adequate precautions were taken for avoiding contamination such as use of separate laboratory rooms for dna extraction , pcr assay procedure and handling of pcr products and use of proper micropipettes . as described previously , results were confirmed by southern hybridization with a radio - labeled internal probe
. for genotyping using rflp pattern analysis , the entire omp1 gene coding for major outer membrane protein ( momp ) was amplified by conventional pcr assay using a set of published primers and procedures described by sayada et al . from 50 endocervical specimens from patients of cervicitis . a few conjunctival specimens from clinically proven trachoma cases
briefly , dna was isolated from 500 l of thoroughly mixed clinical specimens using proteinase k and phenol chloroform extraction as was described before .
dna extracted from c. trachomatis l2 ( 434 bu strain ) grown in the yolk sac of embryonated hen 's egg and purified by renograffin gradient centrifugation was used as positive control and distilled water was used as negative control . pcr assay for amplification of ~1 kb momp gene was done in 100 l volume as was described previously .
ten l of the pcr amplified product was electrophoresed through a 1% agarose gel to confirm the correct amplification product .
the precipitated and purified dna from the remaining 90 l of pcr product was used for rflp analysis with restriction enzyme alu i ( neb , uk ) , was prepared in a 20 l reaction mixture containing 3 g of purified dna , 15 u of alu i enzyme , and 2 l of 10x buffer provided with the enzyme and mili q water qs , and was incubated overnight at 37c .
after inactivation of the enzyme at 65c for 10 minutes , the product was electrophoresed through a 3% agarose gel in an electrophoresis apparatus ( lkb , pharmacia , sweden ) , stained with ethidium bromide and visualized under an uv transilluminator .
in order to attribute clear - cut specificity to the rflp pattern analysis we included a few conjunctival specimens from which the momp gene was pcr - amplified , restriction - digested and the product of this assay was electrophoresed in the same gel .
data were systematically recorded and managed on an excel spread sheet . for comparing the proportion positivity amongst the various disease groups such as cervicitis , infertility , pid and boh , during different time periods ,
also test for trend was employed to determine the significant trend during the period . to assess the relationship of dfa with tissue culture , we compared the sensitivity , specificity , positive predictive value ( ppv ) , negative predictive value ( npv ) , and agreement and their 90% confidence interval values .
in the direct immunofluorescence assay ( dfa ) , the chlamydia trachomatis elementary bodies were visible as regular bright apple green spherical particles .
table 1 and figure 1 depict the results of the dfa tests in the four groups of patients ( total 2466 ) in different block years ( 199499 , 20002004 , and 20052010 ) .
a total of 391 out of 2466 ( 15.85% ) specimens were positive for chlamydia antigen in dfa test . amongst the different categories , 73 of 436 ( 16.74% ) women with cervicitis , 268 of 1671 ( 16.03% ) women with infertility , 12 ( 27.27% ) of the 44 women with pid , and 38 of 315 ( 12.06% ) women with adverse pregnancy outcomes ( boh ) were antigen positive by dfa test .
as is evident grossly from figure 1 and table 1 , there seems to be a trend towards a gradual decline in the antigen positivity rates over the years in all the four disease groups .
however , statistically significant decline was noted only in the infertility group which showed an overall significant decline in the disease prevalence ( figure 1 and table 1 ; trend = 22.97 , p = 0.0001 ) .
a similar trend was also observed when the data were compared between the block years i and ii and the block years i and iii , for the infertility group only ( table 1 ) . in tissue culture isolation ,
bright apple green fluorescent para nuclear chlamydial inclusions were visible in positive specimens . from the 1507 specimens processed for tissue culture isolation , 198 ( 13.1% ) gave positive results ; from the same 1507 specimens chlamydia antigen
the detailed comparative results between dfa and tissue culture isolation are shown in table 2 . in the pcr assay for amplification of c. trachomatis 517 bp cryptic plasmid gene , 44 out of 333 ( 13.2% ) of the cervical specimens showed positive results ; the same 44 specimens were positive for antigen detection by dfa test : both the tests showing complete concordant results in these 333 specimens
. from the 50 endocervical specimens processed for the pcr assay for amplification of the momp gene , 22 ( 44% ) were positive .
in rflp pattern analysis , upon examination of the dna bands in 3% agarose gel stained with ethidium bromide , all the cervical specimens showed a similar pattern , which corresponded to published rflp pattern of c. trachomatis serovar e. for cervical specimens , after complete digestion with alu1 enzyme , 5 dna bands were visualized , corresponding to 2 bands each of 100 bp , one band of 138 bp and 2 bands each of 250 bp .
( figure 2).there was a clear - cut distinction between the rflp patterns of conjunctival and endocervical specimens .
the rflp pattern produced by the conjunctival specimens matched with those of c. trachomatis serovar a .
in the present study , chlamydia antigen could be detected in 391 out of 2466 ( 15.85% ) of patients studied over a 16-year period , significantly in 27.27% cases with pid and 16.03% cases with cervicitis .
barring a few isolated reports , no such long - term study regarding involvement of c. trachomatis in various female genital infections is available from india . according to the isolated reports
, chlamydia antigen could be detected in 38.46% of pid patients from bombay in 1990 , in 35.22% of pid patients from delhi in 1991 , in 35.22% patients of pid , and in 42.8% patients of cervicitis from delhi in 1993 .
results of a few community - based studies spanning 1 - 2-year period to determine chlamydia prevalence in female genital infections were available . according to these reports , in 2000 ,
chlamydia prevalence was 23.2% in female sex workers attending std clinics in bombay , chlamydia antigen positivity was 12.2% in women with vaginal discharge ( cervicitis ) and 28.7% in all symptomatic women in urban slums in delhi in 2000 and 2001 , respectively [ 19 , 20 ] . since the current study is based on presence of laboratory proven chlamydial infection among broadly symptomatic women attending hospital during past 16 years , the results are more or less comparable to other reports from different parts of india . though we presume that studies reporting higher positivity rates might have been conducted on very select group of patients .
as was mentioned earlier , in the present study there was a trend towards an apparent decline in the antigen positivity rates over the years , the exact reasons for which are not clear .
differentiation of c. trachomatis servoars by the use of rflp pattern analysis of amplified momp dna has been used widely [ 9 , 10 , 21 , 22 ] .
this method has an advantage , as it alone can be used for direct typing of most of the serotypes of c. trachomatis [ 15 , 21 ] . in a study by sayada et al .
, 78% of the clinical isolates could be typed directly by using alu 1 enzyme alone . in this study
we compared the banding pattern of alu1 digested momp gene from the clinical samples with the published pattern in the literature and the analysis showed the presence of c. trachoamtis e serovar in the endocervicalspecimens.poole and lamont had concluded from a study that serovars e , d , and f were the most commonly found serovars in patients with urogenital infections .
we could detect only one genotype , serovar e of c. trachomatis in the 22 specimens positive in pcr assay for momp gene .
although detection of only one serovar is uncommon , the small number of specimens processed only from cervicitis might have been the reason . nonetheless , it reveals the most prevalent serovar causing cervicitis .
although pcr - rflp is of importance in the epidemiological studies and very little amplified dna is required , it does not reveal the full extent of sequence variation in some strains [ 15 , 23 ] . however , the rflp analysis using the enzyme alu 1 is still preferred by many and it can differentiate between most of the serovars of c. trachomatis and thus this could be a starting point for further differentiation of the isolates by sequencing techniques .
nevertheless , rflp performed directly with cervical specimens in the present study , showed that , under optimized reaction conditions , amplification of an approximately 1 kb omp1 fragment followed by digestion with alu1 enzyme could determine the most prevalent serovar of c. trachomatis .
this is in agreement with the observations by others . for comparison purposes ,
we had included a few specimens from c. trachomatis eye infections for genotyping , these belonged to serovar a which corroborated with our previous serotyping result .
although we could detect only c. trachomatis serovar e , from india , others have reported presence of servaors d , e , g i , and f , representing 92% of their isolates . in another study from a different part of world , c. trachomatis serovars d , e , and f were found to be the most common types by rflp pattern analysis in 35 specimens from urogenital infections .
overall chlamydia antigen detection rate varied from 12.2% to 27% in different female genital infection patients ( 2466 ) attending hospital over a period of 16 years in new delhi , india .
even though the exact reason was not clear , there was significant decline and an apparent decline in chlamydia antigen positivity between years 19942000 and 200010 , respectively .
in the 333 specimens processed for both antigen detection and pcr assay , equal number of positives ( 13.2% ) was detected with concordant results .
pcr - based rflp pattern analysis concluded the prevalent serovar as c. trachomatis serovar e in cervicitis patients .
Output:
| presence of chlamydia trachomatis in endocervix was determined in 2466 women attending a tertiary care hospital in new delhi , india over a period of 16 years , using a monoclonal - based direct immunofluorescence assay , tissue culture isolation , and a conventional pcr assay .
chlamydia antigen could be detected in 391 out of 2466 ( 15.85% ) of patients studied ; in 27.27% women with pid , 16.74% women with cervicitis , 16.03% women with infertility , and 12.06% women with adverse pregnancy outcomes , respectively .
there was a statistically significant decreasing trend in chlamydia antigen positivity between the years 19941999 and 20002004 ; the apparent decline in antigen positivity between the years 20002004 and 20052010 was not statistically significant .
antigen detection assay detected equal number of positives as the pcr assay ; tissue culture isolation demonstrated lower positivity . in a few representative specimens from cervicitis patients ,
genotyping was done using rflp pattern analysis of c. trachomatis momp gene amplified by pcr assay , all of these belonged to chlamydia trachomatis serovar e. |
PubmedSumm118709 | ***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: magnesium ( mg ) is one of the most common cations in the intracellular fluid space that inhibits calcium entry into cell via blockade of n - methyl - d - aspartate ( nmda ) receptor .
the previous studies have been demonstrated that mg sulfate had effective role in eclampsia , and intravenous administration of mg sulfate also has preventive role in postoperative hyperalgesia .
however , they are accompanied with some side effect , and it is extremely important for the anesthesiologist to have an appropriate tracheal intubation without using neuromuscular blocking agents .
designed a double - blind study in patient with american society of anesthesiologists ( asas ) i and ii , and they reported that mg sulfate improved intubation without using the neuromuscular blocking drug .
hans et al . concluded that intravenous administration of 50 mg / kg of mg reduced the train - of - four ratio in patients when compared with control group . in patient undergoing thyroidectomy , 30 mg / kg of mg sulfate administration prevented remifentanil - induced hyperalgesia while in patient undergoing thoracotomy , a bolus dose of 3050 mg / kg of mg sulfate followed by continuous dose of 500 mg / h during the operation reduced intraoperative analgesic requirement .
therefore , this study was designed to determine the effect of mg sulfate accompanied with propofol and fentanyl as anesthesia induction in 6085-year - old patients undergoing ophthalmic surgery .
this study was designed as a double - blind clinical trial in 100 patients undergoing ophthalmic surgery in feiz hospital during the year of 2013 , and it was approved by isfahan university of medical sciences ethic committee . written informed consent was obtained from each patient after introduce them with study detail and design .
the including criteria was 6085 years old , physical status of i , ii , or iii based on asa , class of 1 , 2 , or 3 from modified mallampati test , class of 1 , 2 , or 3 from upper lip bite test ( ulbt ) , body mass index ( bmi ) between 20 and 30 , and thyromental distance ( tmd ) > 6.5 cm .
as excluding criteria , the patients with a history of hyper reactive airways disease , treatment with calcium channel blockers , renal , cardiovascular , respiratory or hepatic diseases , or allergy to any of study drugs were excluded from the study .
all patients were in non per oral ( npo ) condition for 8 h , and during this period they were received 1/32/3 crystalloid solution based on 4 , 2 , 1 law .
the mallampati class was assessed by asking the patients in sitting posture to open his / her mouth and protrude the tongue as much as possible .
the mallampati classes were classified as class 1 : soft palate , uvula , fauces , pillaris visible ; class 2 : soft palate , uvula , fauces visible ; class 3 : soft palate , base of uvula visible , and class 4 : only hard palate visible .
ulbt was achieved by asking the patients to bite their upper lip with lower incisor , and it was categorized as class 1 : lower incisor can hide mucosa of the upper lip ; class 2 : lower incisor can partially hide mucosa of the upper lip , and class 3 : lower incisor unable to touch mucosa of upper lip .
the tmd was measured from the thyroid notch to the tip of the jaw with head extended .
blood samples were obtained before the operation for determination of serum mg . before and during the operation , all patients were monitored via electrocardiogram , heart rate ( hr ) , oxygen saturation , and noninvasive blood pressure ; systolic blood pressure ( sbp ) and diastolic blood pressure ( dbp ) determination .
the randomization and drug infusion were blind for the anesthesiologist . before infusion of any drugs , intraocular pressure ( iop )
was measured and recorded ( applanation tono - pen , avia , reichert inc . ,
the patients ( total = 100 ) received 40 ( group 1 , n = 25 ) , 45 ( group 2 , n = 25 ) , 50 ( group 3 , n = 25 ) mg / kg of mg sulfate in 100 ml of saline , and saline alone ( group 4 , n = 25 ) .
the infusion time for mg sulfate / or saline was 10 min , and 7 min after the beginning of mg sulfate infusion fentanyl ( 3 g / kg ) was administrated intravenously in the period of 3 min accompanied with oxygenation .
finally , propofol ( 2.5 mg / kg ) was infused intravenously in 15 s , and 1 min later , the patient was subjected to tracheal intubation . the time from laryngoscope entrance to the end of tracheal intubation was recorded .
ten min after tracheal intubation , the second blood sample for mg determination was obtained .
the serum level of mg was measured by an autoanalyzer using pars azmoon ( tehran , iran ) kit . based on the previous study ,
the acceptable intubation condition ( ic ) in was 60% and need to improve to 90% by mg sulfate .
therefore , at 5% level of significant and 75% power , using the following formula including z1/2 = 1.96 , z1=0.67 , p1 = 0.9 and p2 = 0.60 , to estimate the sample size .
n = ( z1/2 + z1 ) ( p1 [ 1 p1 ] + p2 [ 1 p2])/(p1 p2 )
accordingly , at least 25 patients were needed in each group .
data for age , bmi , iop , tmd , sbp , dbp , hr , and laryngoscopic time ( lt ) [ tables 1 and 2 ] , and for mg [ figure 1 ] were reported as a mean standard deviation .
these data were analyzed using one - way analysis of variance ( anova ) and least significance difference as post .
wallis test or mann whitney u - test , p < 0.05 was considered statistically significant .
the patients ' characteristics and demographic data in four groups of patients the patients ' intubation condition in four groups of patients the serum level of magnesium before and after tracheal intubation in patients .
the star indicates significant difference from group 4 using one - way analysis of variance ( p < 0.0001 )
based on the previous study , the acceptable intubation condition ( ic ) in was 60% and need to improve to 90% by mg sulfate . therefore , at 5% level of significant and 75% power , using the following formula including z1/2 = 1.96 , z1=0.67 , p1 = 0.9 and p2 = 0.60 , to estimate the sample size .
n = ( z1/2 + z1 ) ( p1 [ 1 p1 ] + p2 [ 1 p2])/(p1 p2 )
accordingly , at least 25 patients were needed in each group .
data for age , bmi , iop , tmd , sbp , dbp , hr , and laryngoscopic time ( lt ) [ tables 1 and 2 ] , and for mg [ figure 1 ] were reported as a mean standard deviation .
these data were analyzed using one - way analysis of variance ( anova ) and least significance difference as post .
wallis test or mann whitney u - test , p < 0.05 was considered statistically significant .
the patients ' characteristics and demographic data in four groups of patients the patients ' intubation condition in four groups of patients the serum level of magnesium before and after tracheal intubation in patients .
the star indicates significant difference from group 4 using one - way analysis of variance ( p < 0.0001 )
the patients ' characteristics and demographic data in four groups of patients are tabulated in table 1 .
the patients from all groups were candidate for surgery of cataract , strabismus , retina , dacryocystorhinostomy , deep vitrectomy or corneal transplantation with no significant difference between the groups in kind of surgery ( p = 0.59 ) .
the patients ' ic in four groups of patients is tabulated in table 2 . a better mask ventilation feasibility ( mvf ) in mg sulfate 45 group ( group 2 )
was observed when compared with mg sulfate 50 group ( group 3 ) ( p = 0.022 ) and group 4 ( saline group ) ( p = 0.021 ) .
no significant differences were detected in laryngoscopic difficulty ( ld ) , cormack lehane ( cl ) classifications , ic classifications , and intubation response ( itr ) classifications between the groups .
however , the vocal cord movement ( vcm ) and muscle relaxant requirement ( mrr ) in group 4 was significantly different from others groups ( p < 0.05 ) ; that mean mrr was greater in group 4 than other groups .
the lt in group 4 also was greater than other groups significantly ( p < 0.0001 ) .
the average reduction of iop after tracheal intubation was 5.2 4.1 mmhg with no significant differences between the groups .
the data for sbp , dbp , and hr in all the patients were tabulated in table 1 , and no significant differences were observed between the groups . the serum level of mg before and 10 min after the end of mg sulfate or saline infusion is demonstrated in figure 1 . before infusion , the serum level of mg were 1.86 0.18 , 1.89 0.32 , 1.83 0.22 , 1.89 0.21 mg / dl in groups 14 , respectively .
however , it reached to 2.70 0.32 , 2.65 0.35 , 2.56 0.21 , and 1.82 0.0.40 mg / dl accordingly .
no significant differences were obtained before mg sulfate / or saline infusion between the groups .
however , the serum level of mg in saline group ( group 4 ) was less than other groups significantly after intubation ( p < 0.0001 ) .
the patients ' characteristics and demographic data in four groups of patients are tabulated in table 1 .
the patients from all groups were candidate for surgery of cataract , strabismus , retina , dacryocystorhinostomy , deep vitrectomy or corneal transplantation with no significant difference between the groups in kind of surgery ( p = 0.59 ) .
the patients ' ic in four groups of patients is tabulated in table 2 . a better mask ventilation feasibility ( mvf ) in mg sulfate 45 group ( group 2 )
was observed when compared with mg sulfate 50 group ( group 3 ) ( p = 0.022 ) and group 4 ( saline group ) ( p = 0.021 ) .
no significant differences were detected in laryngoscopic difficulty ( ld ) , cormack lehane ( cl ) classifications , ic classifications , and intubation response ( itr ) classifications between the groups .
however , the vocal cord movement ( vcm ) and muscle relaxant requirement ( mrr ) in group 4 was significantly different from others groups ( p < 0.05 ) ; that mean mrr was greater in group 4 than other groups .
the lt in group 4 also was greater than other groups significantly ( p < 0.0001 ) .
the average reduction of iop after tracheal intubation was 5.2 4.1 mmhg with no significant differences between the groups .
the data for sbp , dbp , and hr in all the patients were tabulated in table 1 , and no significant differences were observed between the groups .
the serum level of mg before and 10 min after the end of mg sulfate or saline infusion is demonstrated in figure 1 . before infusion
, the serum level of mg were 1.86 0.18 , 1.89 0.32 , 1.83 0.22 , 1.89 0.21 mg / dl in groups 14 , respectively .
however , it reached to 2.70 0.32 , 2.65 0.35 , 2.56 0.21 , and 1.82 0.0.40 mg / dl accordingly .
no significant differences were obtained before mg sulfate / or saline infusion between the groups .
however , the serum level of mg in saline group ( group 4 ) was less than other groups significantly after intubation ( p < 0.0001 ) .
the main objective of this study was to determine the effect of different dose of mg accompanied with propofol and fentanyl as anesthesia induction in 6085-year - old patients undergoing ophthalmic surgery .
our finding indicated that mvf qualification was better in mg sulfate 45 group ( group 2 ) .
this factor was not determined in aissaoui et al . study . however , similar result to aissaoui et al .
study was found for vcm data indicating the positive effect role of mg sulfate during laryngoscopy .
similar to our study , hans et al . used rocuronium for tracheal intubation , and they reported that administration of mg reestablishes the degree of muscle paralysis .
other study demonstrated that 10 and 20 mg / kg of mg before rocuronium reduced the overall movement in patients . on the contrary ,
some of our findings such as ld , cl , ic , or itr are different from other studies , and possibly the non - similarity is related to our study power .
regarding hemodynamics response , we did not find a significant decrease in sbp , dbp , or hr after drugs infusion and after anesthesia induction while puri et al
study also did not indicate any significant difference in hr and mean arterial pressure between mg sulfate receiver and control groups .
however , no significant difference in serum level of mg was observed when different doses of mg sulfate ( 40 , 45 , or 50 mg / kg ) were infused .
did not measured the serum level of mg , but other studies demonstrated that mg sulfate ( 50 mg / kg ) increase the serum level of mg . in our study , the serum level of mg was increased about 40% which is not clinically significant with any adverse effect .
when clinical limitation is existed to use muscle relaxant , intravenous infusion of mg sulfate could be a choice to facilitate tracheal intubation , and the infused mg sulfate does not elevate the plasma level of mg to clinical significant .
this research was supported by isfahan university of medical sciences ( grant number : 292191 ) .
this research was supported by isfahan university of medical sciences ( grant number : 292191 ) .
has was involved in study design , collecting the data and in preparing the article .
sjh was involved in study design , collecting the data and in preparing the article and data analysis .
mn was involved in study design , part of laboratory data collection , data analysis and preparing the final draft of the article .
Output:
| background : muscle relaxant agents usually use to facilitate tracheal intubation ; however , sometimes limitations exist .
magnesium ( mg ) sulfate is a candidate for muscle relaxant substitute .
this study was designed to determine the effect of mg sulfate accompanied with propofol and fentanyl in patients undergoing ophthalmic surgery.materials and methods : in a double - blind randomized protocol and before tracheal intubation , mg sulfate 40 , 45 , or 50 mg / kg in 100 ml of saline ( groups 13 , respectively ) or saline alone ( group 4 ) were administrated intravenously in 100 patients ( n = 25 in each group ) with the american society of anesthesiologist ( asa ) physical status i , ii , or iii .
the patients ' intubation condition in all subjects were determined and described.results:the patients ' demographic data including age , asa , systolic and diastolic blood pressures , intraocular pressure , and body mass index were not significantly different between the groups . a better mask ventilation feasibility in mg sulfate 45 group ( group 2 ) was observed when compared with mg sulfate 50 ( group 3 ) ( p = 0.022 ) and saline group ( group 4 ) ( p = 0.021 ) . in addition , the vocal cord movement and muscle relaxant requirement in saline group were significantly different from others groups ( p < 0.05 ) .
the laryngoscopic time in saline group was greater than other groups significantly ( p < 0.0001).conclusion : intravenous administration of mg sulfate accompanied with propofol and fentanyl facilitates the tracheal intubation without neuromuscular blocking agents . to avoid mg level increasing in plasma ; however , the low dose of mg sulfate is suggested . |
PubmedSumm118710 | ***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: vascular endothelial cells ( ecs ) constitute the inner lining ( endothelium ) of blood vessels that form an interface between the blood and the vessel wall .
blood vessels alter their morphology and function in response to changes in blood flow , and their responses are based on blood flow detection by the vascular endothelium .
ecs sense shear stress generated by flowing blood and transmit the signal to the interior of the cell , thereby evoking a cellular response .
the ec response to shear stress is closely linked to the regulation of vascular tone , blood coagulation and fibrinolysis , angiogenesis , and vascular remodeling .
ecs also control vascular barrier regulation , passive diffusion , and active transport of substances from the blood .
thus , ecs play important roles in vascular homeostatic functions , and excess activation or dysfunction of ecs is considered to lead to the development of vascular - related diseases , such as restenosis , arteriosclerosis , and cancer .
carbohydrate antigens ( also called glycans ) are expressed on the cell surface as components of glycoproteins , glycosphingolipids , and proteoglycans ; these carbohydrate antigens contribute significantly to fundamental biological functions , such as cell differentiation , cell adhesion , cell - cell interaction , pathogen - host recognition , toxin - receptor interactions , cancer metastasis , immune responses , and regulation of signaling pathways .
several studies have revealed that glycoconjugates play key roles in vascular biology . in this paper
, we describe the importance of glycoconjugates in human ecs , with respect to their regulated expression and functional roles , particularly under pathological conditions .
glycoproteins are proteins that contain oligosaccharide chains ( glycans ) covalently attached to polypeptide side chains .
this glycosylation of proteins is important for their physicochemical and biological properties , such as protein folding , stability , targeting , dynamics , and ligand binding .
the vascular endothelial cadherin ( ve - cadherin ) , including seven potential n - glycosylation sites , is endothelium specific and belongs to endothelial adherens junctions .
human ve - cadherin was purified from cultured human umbilical cord vein endothelial cells ( huvecs ) , and its glycosylation pattern was analyzed in order to enable further functional investigations .
the results revealed that ve - cadherin carries predominantly sialylated diantennary and hybrid - type glycans in addition to some triantennary and high - mannose - type species ( sialylated hybrid type is shown in figure 1(a ) ) .
sialidase treatment of whole cells to remove cell surface sialic acids changed ve - cadherin immunofluorescence from a continuous netlike superstructural organization to an unevenly scattered one .
these results indicate that cell surface sialic acids might play a role in ve - cadherin organization . to date
, several studies have been performed to unravel the relationship between changes in the expression of carbohydrate structures and the function of ecs in pathological conditions .
tnf- is one of the inflammatory factors that activate endothelial cells at sites of injury to recruit immune cells in acute and chronic inflammatory processes .
treatment with tnf- differentially modulates a set of glycosylation - related genes , resulting in the increase of the cell membrane - associated glycans , such as -2,6-sialic acid and fucose--1,2-galactose--1,4-n - acetylglucosamine .
also , tnf- stimulates endothelial expression of n - glycans , specifically the high - mannose and/or the hybrid types ( figures 1(b ) and 1(c ) ) , at cell junctions , and these epitopes play a role in modulating monocyte rolling and adhesion to the endothelium . in pathological conditions such as tumorigenesis and atherogenesis , endothelial dysfunction
may be related to a change in cell surface glycans as follows . using a flow cytometry assay with glycan - specific lectins , the expression profiles of a selected group of 9 carbohydrate structures ( -1,6-glcnac branching , high - mannose n - glycans ,
-linked fucose residues , n - acetylglucosamine , -2,3-sialic acid , n - acetyllactosamine , -2,6-sialic acid , -mannose , and -1,4-galactose ) were compared in huvecs under control and tumor - conditioned medium- ( tcm- ) treated conditions .
the expression of 6 of these structures ( -1,6-glcnac branching , high - mannose n - glycans , n - acetyllactosamine , -2,6-sialic acid , -mannose , and -1,4-galactose ) increased significantly after tcm treatment .
in particular , the -1,6-glcnac branching glycan expression level was greatly elevated after the stimulation . this -1,6-glcnac branching glycan was demonstrated to initiate endothelial cell contraction and gap formation , and these events lead to subsequent biological events such as tumorigenesis .
high - mannose - type n - glycans increase in haecs exposed to oscillatory shear or tnf- .
increasing surface n - linked mannose by inhibiting n - glycan processing potentiated monocyte adhesion under flow during tnf- stimulation .
conversely , enzymatic removal of high - mannose n - glycans or masking mannose residues with lectins significantly decreased monocyte adhesion under flow .
these results , therefore , indicate that surface n - linked mannose on ecs is a novel ligand for monocyte adhesion during atherogenesis .
a glycosphingolipid ( gsl ) is composed of a glycan structure attached to a lipid tail containing the sphingolipid ceramide .
gsls have frequently been used as important developmental marker molecules and have been suggested to have important biological functions [ 3 , 9 ] .
the expression profile of gsls in huvecs was investigated under normal conditions and after activation by inflammatory stimuli .
inflammatory cytokines , such as ifn- and il-1 , have been known to alter expression of cell surface molecules in ecs .
ifn- has a striking effect on the surface expression of gsls , in particular on the surface expression of the major neutral gsl , globoside ( globotetraosylceramide , gb4cer ) ( figure 1(d ) ) , but ifn- does not alter the total quantity of gsls .
by contrast , il-1 increases the cell content of neutral and acidic gsls but does not alter their surface expression .
ecs are believed to play an important role in the pathogenesis of hemolytic uremic syndrome ( hus ) .
ec damage by escherichia coli verocytotoxin in vitro is potentiated by additional exposure to inflammatory mediators such as tnf-. the inflammatory mediators tnf- and il-1 make ec sensitive to verotoxin by elevation of verotoxin receptors such as gsl globotriaosylceramide ( gb3cer / cd77 ) ( figure 1(e ) ) on the cell surface [ 12 , 13 ] .
ecs demonstrated that the level of ec sensitivity to verotoxin depends on the expression of gb4cer synthase .
the mechanism of vegf - driven angiogenesis involving lactosylceramide ( laccer ) ( figure 1(f ) ) was examined in huvecs and haecs by rnai - mediated silencing of laccer synthase expression ( galt - v ) and by use of the pharmacological inhibitor of laccer synthase , d - threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol ( d - pdmp ) .
laccer contributes to vegf - induced platelet ec adhesion molecule-1 ( pecam-1 ) expression and angiogenesis [ 15 , 16 ] .
this suggests that laccer is important in vegf - implicated angiogenesis associated with coronary heart disease , vascular complications in diabetes , inflammatory vascular diseases , and tumor metastases .
inhibition of ganglioside gm3 ( figure 1(g ) ) biosynthesis with the glucosyltransferase inhibitor , n - butyldeoxynojirimycin ( nb - dnj ) , increased the ec proliferation and the phosphorylation of vegfr-2 and akt .
thus , this report concludes that gm3 has antiangiogenic action in ecs and may possess therapeutic potential for reducing tumor angiogenesis .
sulfoglucuronosyl paragloboside ( sgpg ) ( figure 1(h ) ) , a minor gsl in ecs , is a ligand for l - selectin .
inflammatory cytokines such as tnf- and il-1 upregulate sgpg expression in human brain cerebromicrovascular ecs ( sv - hcecs ) by stimulating the gene expression of the p and s forms of glucuronosyltransferases ( glcatp and glcats ) and the human natural killer antigen ( hnk-1 ) sulfotransferase ( hnk-1 st )
downregulated sgpg expression , inhibited cytokine - stimulated t - cell adhesion , and offered protection against apoptosis .
this paper indicates the functional importance of sgpg expression for brain - associated ecs in neuroinflammatory diseases .
sgpg expression was inhibited by transfecting the cells with hnk-1 st gene sirna , and sgpg synthesis was promoted by overexpressing glcatp and glcats . and
then , either up- or downregulation of sgpg reduces activation of the nf-b pathway , which is mediated by the accumulation of inhibitor of b ( ib ) .
proteoglycans ( pgs ) are macromolecules composed of a specific core protein substituted with covalently linked glycosaminoglycan ( gag ) chains , namely , chondroitin sulfate ( cs ) , dermatan sulfate ( ds ) , and heparan sulfate ( hs ) .
hyaluronan ( ha ) is the only gag synthesized in a free form not covalently bound to a core protein .
gags are linear , negatively charged polysaccharides comprised of repeating disaccharides of acetylated hexosamines ( n - acetyl - galactosamine or n - acetyl - glucosamine ) and mainly uronic acids ( d - glucuronic acid or l - iduronic acid ) sulfated at various positions . in ha , there are no chemical modifications such as sulfation and epimerization .
pgs can be classified into two main groups according to their localization : those extracellularly secreted and those associated with the cell surface .
the secreted group consists of pgs involving large aggregating pgs , namely , hyalectans ( e.g. , versican ) , small leucine - rich pgs ( slrps ) , and basement membrane pgs ( e.g. , perlecan ) .
cell - surface - associated pgs are divided into two main subfamilies : syndecans and glypicans [ 21 , 22 ] .
pgs perform numerous biological functions , act as structural components in tissue organization , and affect several cellular parameters , such as cell proliferation , adhesion , migration , and differentiation .
pgs interact with growth factors and cytokines , as well as with growth factor receptors , and they are implicated in cell signaling . to clarify the roles of hs in endothelium under pathological conditions , hs expression on human ecs was studied following stimulation by inflammatory or hyperglycemic conditions .
it was found that il-1 , tnf- , and ifn- influence hs expression significantly in huvecs .
also , c - reactive protein , the prototypic marker of inflammation and cardiovascular risk marker , has been shown to promote atherogenesis , and increased levels of c - reactive protein are associated with endothelial dysfunction .
c - reactive protein treatment caused the expression of hs to significantly reduce . in diabetes , the endothelium is exposed chronically or transiently to hyperglycemic conditions .
in addition , endothelial dysfunction in diabetes is related to changes in the inflammatory response and turnover of the extracellular matrix . in hyperglycemic conditions , short - term inflammatory stimuli affected both the size and the sulfation pattern of hs on ecs , with the outcome depending on the type of stimulus .
thus , modification of hs under pathological conditions is considered a major cause of endothelial dysfunction , resulting in the disturbance of vascular integrity and barrier properties , due to decreased negative charge and increased permeability , and the consequent release of bioactive substances such as cytokines , enzymes , and growth factors . to date
adhesion of leukocyte to ecs is partly dependent on hs that binds to l - selectin .
the s100 family heterodimer , mrp-8/14 complex , which is abundantly expressed in inflamed endothelium , binds to ecs via the mrp-14 subunit , interacting chiefly with hs .
it has also been shown that hmgb1 ( high - mobility - group protein b1 ) , an inflammatory cytokine , and receptor for advanced glycation endproducts ( rages ) bind to hs . in another study ,
falciparum - infected erythrocytes ( parasitized red blood cells ) adhere to hs on ecs .
binding via hs followed by sequestration may be related to the severity of the diseases .
rnai - mediated downregulation of hsulf-1 , which selectively removes 6-o - sulfate from hs , resulted in increased proliferation mediated by hs - dependent fgf-2 , hepatocyte growth factor , and vegf165 .
downregulation also enhanced downstream signaling through the extracellular signal - regulated kinase pathway , when compared with untreated cells .
another study confirmed the importance of hs 6-o - sulfate in ec function . reducing hs 6-o - sulfotransferase-1 ( hs6st-1 ) or 6-o - sulfotransferase-2 ( hs6st-2 ) expression in ecs with rnai affected the prevalence of hs 6-o - sulfate moieties in hs sequences ; 1%40% reduction in 6-o - sulfates
these data indicate that 6-o - sulfate moieties in endothelial hs are of major importance in regulating fgf2- and vegf165-dependent ec functions .
cd97 , which is highly expressed on various inflammatory cells and some carcinomas , contributes to inflammation - mediated angiogenesis and possibly tumor progression .
cd97 acts as a potent chemoattractant for the migration and invasion of ecs , and this function is integrin dependent .
one study showed that coengagement of 51 and cs proteoglycan by cd97 synergistically initiates ec invasion .
chronic inflammation has a critical role in the onset of several diseases , including atherosclerosis , and endothelial dysfunction is a key early step in these diseases .
a study has shown that the expression of ha on huvecs is induced by il-15 , which has been suggested to play a role in the setting of the chronic autoimmune disease , particularly in the recruitment and activation of synovial t - cells .
the results of the study suggest that il-15 can regulate ec function and thereby enable a cd44-initiated adhesion pathway that facilitates the entry of activated t lymphocytes into inflammatory sites . in haecs , c - reactive protein , the expression of which is related to inflammation as well as endothelial dysfunction , dose dependently increased ha release .
this is thought to result in ec dysfunction by , for example , increasing monocyte - ec adhesion .
another study found that il-1 , tnf- , and tnf- strongly induce ha synthesis via the nf-b pathway .
moreover , it has been verified that u937 monocyte adhesion to stimulated ecs depends strongly on ha .
thus , in chronic inflammation , elevation of ha expression via inflammatory stimulation promotes adhesion of leucocytes to ecs , resulting in vascular - related diseases , such as atherosclerosis .
recent in vivo studies revealed that the inner blood vessel surface is lined with an endothelial surface layer at least 0.5 m thick , which serves as a shield protecting the vessel wall from arteriosclerosis .
ha seems to be an essential component that is related to the atheroprotective properties of this surface structure .
it has also been shown that ha is increased in a shear - stress - dependent manner via the phosphatidylinositol 3-kinase - akt pathway [ 35 , 36 ] .
thus , fluid shear stress stimulates the incorporation of ha into the glycocalyx , which may contribute to its vasculoprotective effects against proinflammatory and pro - atherosclerotic stimuli .
it has been reported that the amounts of heparan sulfate ( hs ) in perlecan ( an hspg ) are different in huvecs and haecs and that hs expression affects perlecan - dependent adhesion of vascular cells .
the functions of hs in endothelial perlecan were further investigated [ 38 , 39 ] .
the studies show that the binding abilities of fgf-1 and fgf-2 to endothelial perlecan differ depending on the hs structures in the different cell types .
one potential mechanism involves hyperglycemia - induced changes in arterial wall extracellular matrix components leading to increased atherosclerosis susceptibility .
a decrease in hs gag has been reported in the arteries of diabetics . in haecs ,
in addition , endothelial dysfunction in diabetes is related to changes in the inflammatory response and the turnover of extracellular matrix . in hyperglycemic conditions ,
perlecan , but not other hspgs , is dramatically downregulated in ecs treated with antiangiogenic cleaved and latent forms of antithrombin [ 41 , 42 ] .
the previously established key role of perlecan in mediating fgf-2 stimulation of ec proliferation and angiogenesis suggests that a primary mechanism by which antiangiogenic antithrombins exert their effects is through the downregulation of perlecan expression .
the role of perlecan in the antiangiogenesis function of nk4 , an angiogenesis inhibitor , was also studied . in this study ,
knockdown of perlecan expression in ecs by rnai significantly reduced the inhibitory effect of nk4 on fibronectin assembly and cell spreading .
thus , this study indicates that the association of nk4 with perlecan plays a key role in angiogenesis inhibition by nk4 .
endocan is a novel small soluble dermatan sulfate proteoglycan ( dspg ) produced specially by ecs . in sv40-transfected human ecs ( sv1 cells ) ,
endocan regulates hgf / sf - mediated mitogenic activity and may support the function of hgf / sf , not only in embryogenesis and tissue repair after injury but also in tumor progression .
additionally , endocan expression in huvecs is upregulated by tumor - cell - conditioned medium .
moreover , treatment with vegf resulted in dose- and time - dependent increases in endocan mrna .
the results suggest that endocan is preferentially expressed in tumor endothelium in vivo and that its expression is regulated by tumor - derived factors .
now , it is highlighted that endocan is a marker of ec activation during growth of the new vessels required for tumor progression .
decorin , a member of the small leucine - rich repeat proteoglycan ( slrp ) family , is expressed by sprouting ecs during inflammation - induced angiogenesis in vivo and by human ecs cocultured with fibroblasts in a collagen lattice .
activation with il-10 or il-6 treatment induces decorin mrna in human ecs . as function of decorin in human ecs
, it has been reported that decorin core protein can bind to and activate insulin - like growth factor - i receptor ( igf - ir ) and that decorin promotes 21 integrin - dependent ec adhesion and migration on fibrillar collagen type i .
it is now understood that modulation of cell - matrix interactions by decorin plays a key role during angiogenesis .
primary human ecs , if stimulated with tnf- or vegf , alter their expression of versican ( a large aggregating cspg ) by de novo transcription of the v3 isoform and by exhibiting a moderate v1/v2 production
. induced versican synthesis and de novo v3 expression were also observed in ecs induced to migrate in a wound - healing model in vitro and in angiogenic ecs forming tubule - like structures in matrigel or fibrin clots .
this study indicates that versican produced from ecs plays a key role in the pathological conditions such as inflammation , angiogenesis , and wound healing .
when ea.hy 926 cells , one of human ecs , form monolayer cultures typical of macrovascular ecs , they express and synthesize detectable amounts of biglycan and pg-100 ( members of the small leucine - rich repeat proteoglycan family ) .
tnf- , responsible for changing the morphology of the cells from a polygonal to a spindle shape and for stimulating the detachment of the cells from the culture dish , markedly decreased the synthesis of biglycan .
by contrast , pg-100 expression was increased in response to fgf-2 , fgf-7 , tnf- , and tgf- .
although the functional roles of biglycan and pg-100 are not yet clearly understood , their different responses to the stimuli may be critical for the progression of vascular diseases .
another study has shown that antiangiogenic antithrombin treatment significantly decreases biglycan in huvecs , suggesting that a mechanism of antiangiogenic antithrombins is through the downregulation of proangiogenic biglycan .
recently , the contribution of glypican-1 to the cell cycle and proliferation has been demonstrated in ecs .
proteoglycans ( pgs ) are important constituents of the plasma membrane and of the basement membrane supporting the ec layer .
changes in the amounts or the structures of pgs in the endothelium may affect important functions , such as turnover of lipoproteins , filtration properties , and regulation of chemokines during inflammation , which are all relevant to diabetes .
in huvecs , exposure to high glucose ( hyperglycemic condition ) leads to decreased secretion of syndecan-1 .
thrombospondin-1 ( tsp-1 ) , an extracellular matrix protein , modulates focal adhesion in mammalian cells and exhibits dual roles in angiogenesis .
there are indications that binding of tsp-1 to syndecan-4 proteoglycan mediates tubulogenesis and their protection from apoptosis .
syndecan-2 , the major syndecan expressed by human microvascular ecs ( hmecs ) , is regulated by growth factors and extracellular matrix proteins , in both bidimensional and tridimensional culture conditions .
downregulation of syndecan-2 reduced the spreading and adhesion of hmecs , and it not only enhanced their migration but also impaired the formation of capillary - like structures . therefore , syndecan-2 has an important function in some of the necessary steps in the angiogenic process .
syndecan-1 is a critical regulator of v3 and v5 integrins during angiogenesis and tumorigenesis , and it is inhibited by the novel peptide called synstatin .
galectins are a family of lectins that bind to -galactosides via a carbohydrate recognition domain containing many conserved sequence elements .
there are currently 15 known mammalian galectins , which are involved in a variety of biological processes .
expression of galectin-1 in cultured human ecs was first shown in 1995 by baum et al . .
they also showed that activation of cultured ecs by minimally oxidized low - density lipoprotein ( mm - ldl ) or cytokines and lps increases galectin-1 expression , as determined by elisa , northern blot analysis , and high - throughput cdna sequencing .
another study found that poly ic , a synthetic analog of double - stranded rna ( dsrna ) , enhances the expression of galectin-9 mrna and protein in ecs in concentration- and time - dependent manners .
treatment of cells with dsrna in vitro mimics viral infection and regulates the expression of various genes .
thus , it has been proposed that upregulation of galectin-9 expression by poly ic in the vascular endothelium may be part of the mechanism for leukocyte trafficking through the vascular wall after viral infection .
subsequently , galectin-1 , -3 , -8 , and -9 expression levels in quiescent ecs were measured , and the expression and distribution of these galectins changed after activation with tumor - derived culture medium .
recently , it was reported that galectin-9 protein expression is positively regulated by histone deacetylase 3 in ecs .
this study provides new evidence that hdac3 regulates galectin-9 expression in ecs via interaction with the pi3k - irf3 signaling pathway .
cancer - associated carbohydrate t antigen plays a leading role in docking breast and prostate cancer cells onto endothelium by specifically interacting with ec - expressed galectin-3 .
one of the low - molecular - weight synthetic lactulose amines ( slas ) , n , n-dilactulose - octamethylenediamine ( d - ldo ) , severely impaired tube formation of ecs .
d - ldo inhibited the binding of galectin-1 and/or galectin-3 to the highly glycosylated protein 90 k. thus , d - ldo may be a new galectin inhibitor for blocking angiogenesis . in huvecs , knockdown of galectin-3 and mgat5 , an enzyme that synthesizes high - affinity glycan ligands of galectin-3 , reduced vegf - a - mediated angiogenesis in vitro . a direct interaction was detected on the plasma membrane between galectin-3 and vegf - r2 , and this interaction was dependent on the expression of mgat5 . using immunofluorescence and cell surface labeling , an increase in the level of internalized vegf - r2 was observed in both mgat5 and galectin-3 knockdown cells , suggesting that galectin-3 retains the receptor on the plasma membrane via lattice formation .
thus , galectin-3 contributes to the plasma membrane retention and proangiogenic functions of vegf - r2 in ecs .
heparanase is an endo--d - glucuronidase responsible for heparan sulfate ( hs ) degradation at a limited number of sites , yielding hs fragments of an appreciable size ( 57 kda ) and with biological potency [ 69 , 70 ] . in 1991
the hs content of the endothelium is reduced under hyperglycemic conditions , and it may contribute to the pathogenesis of atherosclerosis .
this suggests that hs reduction in ecs is due to increased heparanase production under hyperglycemic conditions .
recently , high - glucose - induced heparanase production and hs degradation were detected in human several types of ecs [ 72 , 73 ] .
in fact , functional analyses revealed that the expression of heparanase contributed to ec migration and proliferation .
furthermore , it has been shown that ec proliferation and migration correlate with akt and erk phosphorylation levels .
sialidases are glycosidases that catalyze the removal of -glycosidically linked sialic acid residues from the carbohydrate groups of glycoproteins and glycolipids . to date
, at least 4 mammalian sialidases , neu14 , have been identified [ 74 , 75 ] .
whether the ec surface expresses sialidase activity was not known until recently . in human lung microvascular ecs ( hmvec - ls ) and human pulmonary artery ecs ( hpaecs ) , neu14 expression was examined , and functional analysis by knockdown and overexpression was performed .
these ecs express catalytically active neu1 and neu3 sialidases , and neu1 restrains the endothelial migratory response to wounding .
in this paper , we described previous research about glycoconjugates in human ecs . to date , the functional roles of glycoconjugates in vivo have been investigated in animal disease models ( e.g. , atherosclerosis ) ( figure 2(a ) ) . in apoe - null mice ,
this contribution may involve increased ldl retention , altered vascular permeability , or other mechanisms .
additionally , a proatherosclerosis function of biglycan has been suggested by the retention of ldl .
abnormal angiogenesis plays a critical role in the pathogenesis of many diseases such as cancer , ischemic vascular disorders , and diabetic retinopathy .
in particular , the importance of hs in tumor angiogenesis has been demonstrated by tumor - based studies in mice with endothelial - targeted genetic alterations in hs biosynthesis ( figure 2(a ) ) .
thus , the functional importance of glycoconjugates in vascular - related diseases has been demonstrated .
evidence from examination of human ecs indicates that glycoconjugates also serve as biomarkers and functional players in the human endothelium under pathological conditions as described here ( figure 2(b ) ) .
therefore , although many issues await clarification , glycoconjugates are attractive potential targets for the prevention and treatment of vascular - related diseases . in recent years , the incidence of vascular - related diseases , such as cancer , cardiac disease , and cerebrovascular disease , has increased with an aging population , and prompt countermeasures are sought . hence , further study of the functional roles of glycoconjugates in human ecs and identification of specific glycoconjugates related to disease are required in order to develop therapeutic strategies for vascular - related diseases , such as peripheral artery disease ( pad ) ( figure 2(c ) ) .
Output:
| vascular endothelial cells ( ecs ) form the inner lining of blood vessels .
they are critically involved in many physiological functions , including control of vasomotor tone , blood cell trafficking , hemostatic balance , permeability , proliferation , survival , and immunity .
it is considered that impairment of ec functions leads to the development of vascular diseases .
the carbohydrate antigens carried by glycoconjugates ( e.g. , glycoproteins , glycosphingolipids , and proteoglycans ) mainly present on the cell surface serve not only as marker molecules but also as functional molecules .
recent studies have revealed that the carbohydrate composition of the ec surface is critical for these cells to perform their physiological functions . in this paper , we consider the expression and functional roles of endogenous glycoconjugates and related molecules ( galectins and glycan - degrading enzymes ) in human ecs . |
PubmedSumm118711 | ***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 principal drive underlying many in situ high - pressure studies is the need to understand the materials that make up the earth under conditions in which they are stable , typically above 2 gpa .
however , many important phenomena in technologically relevant materials occur at more moderate pressures and , as such , the ability reliably to access less high pressure is valuable . the paris edinburgh ( pe ) pressure cell ( besson et al . , 1992 ;
, 2004 ) represents a robust compact easy - to - use large - volume pressure apparatus suitable for x - ray scattering structural studies .
it generates pressure through compression of the sample , confined within a gasket , between a pair of anvils by means of a hydraulic pump . for a given gasket size
, the physical properties of the gasket material largely limit the range of pressures accessible . at the upper bound ,
the gasket material extrudes and no longer keeps the anvils apart or the anvils themselves start to deform plastically . at the lower limit , the intrinsic strength of the gasket material must be overcome before controllable pressure is generated at the sample .
the boron epoxy composite routinely used as gaskets for x - ray scattering experiments with the pe cell ( mezouar et al .
, 1999 ) allows access to pressures up to 4 gpa for gaskets of 10 mm diameter , and 7 and 18 gpa for 7 and 5 mm gaskets , respectively .
here we demonstrate the viability of softer gasket materials ( k = 3.3 gpa ) , used in combination with fluid pressure - transmitting media , to allow controlled access to lower , hydrostatic pressures for x - ray scattering measurements for bragg and pair distribution function ( pdf ) analysis with sodium chloride used as both sample and internal pressure standard ( decker , 1971 ) .
although diamond - anvil cells can also be utilized in this range , they are not always ideal for these types of experiments due to the large contribution of compton scattering from the diamonds to the measured intensities and the comparatively small sample volume ( martin et al . , 2005 ) .
a gasket , of appropriate shape for use with anvils with 10 mm diameter conical indents ( 3.5 mm diameter sample cavity ) , was machined from commercially available torlon 4503 rod .
a manually pre - compressed nacl pellet was loaded into the gasket , wet with fluid pressure - transmitting media ( 2-propanol ) and sandwiched between anvils ( tungsten carbide , wc , inserts ) within a vx5 model pe cell .
the anvils were covered with polyimide film to minimize contact with the fluid pressure - transmitting media .
the pe cell was mounted on the instrument at beamline 11-id - b at the advanced photon source , argonne national laboratory , with the incident ( and scattered ) beam directed through the gasket via the gap between the anvils ( fig . 1 ) .
high - energy x - rays ( 90.48 kev , = 0.1370 ) were used in combination with a mar-345 image - plate detector to record diffraction images ( chupas et al .
data were collected at a sample - to - detector distance of 791.14 mm , at ambient pressure and as the applied pressure was increased at 10 ( 2 ) bar ( 1 mpa ) intervals up to 100 bar ( 10 mpa ) .
raw images were processed using fit2d ( hammersley , 1997 ; hammersley et al .
the lattice parameters were obtained from rietveld refinement of a structural model for nacl within gsas ( r
wp = 3.43.6% ) ( larson & von dreele , 1987 ) . the sample pressure was determined from the pressure - induced changes in cell volume based on a third - order birch murnaghan equation of state for nacl ( k
0 = 23.5897 gpa and = 4.8206 ) . for pdf analysis at the maximum pressure , the sample - to - detector distance was decreased ( 232.12 mm ) and higher - energy x - rays ( 126.8 kev , = 0.09778 ) were used to collect data to high values of momentum transfer ( q 17 ) .
, 2004 ) , subtracting the contributions from the sample environment and background to the measured diffraction intensity as measured by translating the pe cell such that x - rays were incident on the gasket only .
corrections for multiple scattering , x - ray polarization , sample absorption , and compton scattering were then applied to obtain the structure function s(q ) .
direct fourier transform of the reduced structure function f(q ) = q[s(q ) 1 ] up to q
max 17 gave g(r ) , the pair distribution function .
refinement of a model against g(r ) was performed within pdffit ( proffen & billinge , 1999 ) .
above 10 bar applied pressure , the torlon gasket was sufficiently compressed to generate pressure at the sample .
this corresponds to 10% of the applied pressure required to generate pressure using the boron epoxy gasket in an identical setup .
the sample pressure increased with applied pressure at a rate of 0.045 gpa per 10 bar ( fig .
2 ) until gasket failure at above 100 bar ( 0.042 gpa ) .
in contrast to the near linear behavior observed here , the increase in sample pressure with the boron epoxy gasket often decreases at higher pressures with plastic deformation of the anvils . while no strain - texture was evident for the sample peaks , the development of diffraction texture at low angle along the direction of compression ( x ) was observed with increasing pressure ( fig . 2 ) .
this arose from strain - induced ordering in the gasket material ( gorlier et al .
, 2001 ) and had minimal impact on the intensity in the perpendicular wedges of the image used to obtain the one - dimensional diffraction patterns .
near hydrostatic conditions were maintained with the inclusion of alcohol - based fluid pressure - transmitting media . under these conditions ,
the diffraction peaks from the sample shifted smoothly to shorter d - spacing with increasing pressure , with minimal broadening ( fig .
in contrast , data measured without pressure - transmitting media , with slightly different experimental conditions ( lower resolution due to the shorter sample - to - detector distance and wavelength used ) , showed significant peak broadening upon application of pressure . at the pressures achieved with the torlon gasket , it was not necessary to encapsulate the sample / fluid to prevent the anvil failure following contact with fluid seen at higher pressures ( marshall & francis , 2002 ) . here
as torlon is highly plastic , the fluid is reliably contained at low pressure without cracking , as often occurs for boron epoxy .
4 . the pdf calculated for the refined model of nacl was in good agreement with the data ( r = 0.1513 ) .
the contribution to the scattering from torlon is smoother , less structured with lower intensity at high q than that from boron epoxy , and this aids in the accurate normalization of the data .
the tolerance of the normalization to the neglected scattering from the pressure - transmitting media is presumably due its extremely weak contribution .
the use of smaller gaskets shifts the accessible pressure range to higher values , by factors of 24 for boron epoxy .
similar gains are expected for torlon gaskets such that pressures up to 0.81.6 gpa may be achieved .
it may also be possible to vary the pressure range by using other gasket materials .
offline tests on vespel sp-1 ( polyimide , k = 2.4 gpa ) gaskets indicates that they withstand 60% of the maximum applied pressure tolerated by torlon 4503 .
Output:
| the use of a polymeric ( torlon or polyamide imide ) gasket material in a paris edinburgh pressure cell for in situ high - pressure x - ray scattering measurements is demonstrated .
the quality of the data obtained in this way is suitable for bragg and pair distribution function analysis . |
PubmedSumm118712 | ***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: guide catheter induced dissection of coronary arteries is an uncommon but serious complication of coronary angioplasty ( 1 ) .
treatment can include emergent coronary artery bypass grafting to the affected vessel or percutaneous intervention including wiring the true lumen and exclusion stenting of the dissection flap to prevent further propagation ( 1 ) .
detailed descriptions have been published of techniques of intentional passage of guide wires into the false lumen and reentry into the true lumen with chronic total occlusions ( 2 - 3 ) .
we present an unusual case of what appeared to be successful intentional false lumen stenting with reentry into the true lumen of an iatrogenic dissection of the right coronary artery with restoration of timi iii coronary flow which , one year later , was complicated by recanalization of the true lumen and occlusion of the stented false lumen causing symptomatic angina . to our knowledge , this is the first reported case of complete longitudinal late recanalization of the true lumen of a type f long dissection after acute true - false - true lumen stenting of acutely dissected right coronary artery .
a 66-year old female with no significant past medical history presented to hospital with a 4-week history of progressive congestive heart failure .
echocardiography demonstrated a globally reduced left ventricular ejection fraction of 24% and the patient was referred for coronary angiography to rule out an ischemic etiology .
angiography of right ( rca ) and left coronary arteries showed only minimal irregularity consistent with a non - ischemic cause of the patient s cardiomyopathy , likely myocarditis .
twenty minutes post angiography the patient developed severe chest pain and st segment elevation in the inferior led to third degree atrioventricular block .
the patient was rapidly treated with atropine and dopamine and brought back to the ward with an initial systolic blood pressure of 60 - 70 mm hg .
b ) type f spiral dissection of rca from ostium to crux with large false lumen opacification .
c ) with ongoing contrast injection , perforation of contrast back into true lumen of pl , pda remains occluded .
d ) wire placed through false lumen in mid - rca into distal true lumen of pl .
e ) two bare metal stents implanted in ostial to mid - rca restoring timi 3 flow to pl .
f ) pilot wire used to perforate back into pda with ostial pda hazy dissection .
repeat angiography demonstrated a spiral dissection ( type f ) of the rca from the ostium to the crux beyond which the vessel was occluded on first injection ( fig .
in fact , the continued first injection spread the dissection ( hydraulic ) into the posterolateral ( pl ) branch with reentry of contrast perforating into the true lumen distally with branches of the pl visible ( fig .
there were no acute marginal branches seen coming off the course of the rca likely indicating large diffuse false lumen .
immediately the rca ostium was engaged at a slight distance from the ostium with a jr 4 guiding catheter and pilot 50 wire ( abbott vascular inc . )
the catheter was left outside the ostium to allow at least initial entry into true lumen of the rca .
after surgical consultation , given the patient s extremis status , coronary stenting was recommended .
although the wire was likely placed in the false lumen throughout the course of the mid - rca , it was felt to be in true lumen distally due to easy entry into branches of the pl vessel .
the mid - rca was then dilated with 3 mm balloons improving flow to the distal vessel .
subsequently , a 3.5 30 mm bare metal stent was used to the mid - rca and an overlapping 3.5 38 mm bare metal stent was deployed to the proximal rca at 16 atm . both were post - dilated with a 3.75 mm non - compliant balloon at high pressures ( 18 atm ) throughout ( fig .
this improved flow to the pl branch of the rca to timi 3 with resulting improvement in hemodynamics and chest pain and significant st segment resolution .
after repeated attempts , the pilot-50 wire was able to perforate from this distal false lumen into the occluded pda ( fig .
there was obvious dissection seen at the ostium of the pda with distal true lumen re - entry of the pda with all branches and perforators visualized ( fig .
1f ) . to achieve as complete a revascularization as possible , it was decided to place a 2.25 12 mm drug eluting stent at the ostium of pda with restoration of good flow into the distal pda ( fig
there was a discrete residual dissection seen in the mid - pda in the rao ( right anterior oblique ) view likely demonstrating the point of reentry to true lumen of the pda ( fig .
timi 3 flow had been achieved in the rca and both major branches and hemodynamic stability had been achieved with improvement in st segments , in spite of residual dissection in the pda .
however , given the patient s extremis status and the fact that no further stent implants were planned into the distal rca ( given the timi 3 flow and no angiographic obstructive dissection ) intravascular ultrasound was not performed .
the patient was weaned off dopamine immediately and showed good recovery in the coronary care unit .
she was subsequently discharged with a peak ck level of 1717 u. early follow up showed no angina and with aggressive medical therapy with ace - inhibition and b - blockade the ejection fraction improved to 55% over the next six months with no clinical heart failure symptoms . however , 12 months post angioplasty , the patient re - developed ccs class ii - iii angina .
after an initial trial of medical therapy with no improvement , coronary angiography was performed .
angiography revealed that the proximal half of the ostial rca stent was patent with mild restenosis at the ostium ( fig .
however , the distal half of this stent appeared occluded and , in fact , the ongoing vessel lumen appeared adjacent to the occluded stent .
this pattern continued into the previously placed mid - rca stent which was also occluded , again with an adjacent lumen recanalized beside the occluded midbody stent ( fig .
this true lumen recanalization appeared to form a helix around the occluded stents , likely representing the original course of the spiral dissection ( fig .
the previously placed stents were clearly demonstrated to be extraluminal , as anticipated in the original procedure .
the recanalized true lumen also demonstrated all the previous acute marginal / right ventricular branches seen on the original vessel demonstrating true lumen recanalization .
this was consistent with recanalization of the true lumen , and occlusion of the stents previously deployed to the false lumen .
although an attempt at percutaneous coronary intervention ( pci ) was made , no device ( balloon , intravascular ultrasound ) would cross beyond the proximal rca as expected , given that the true vessel lumen probably continued onwards in a sideways fashion from the proximal stent struts , likely at the original transition point from true to false lumen .
a ) lao 30 view rca one year post stenting demonstrating initial true lumen stenting followed by occluded false lumen stents ( arrows ) and recanalized true lumen in a helical configuration .
b ) rao 30 view of same rca demonstrating side by side placement of recanalized true lumen and unopacified false lumen stents in a spiral fashion similar to the original planes of dissection .
gated computed tomography ( ct ) coronary angiogram obtained prior to coronary artery bypass graft ( cabg ) revealed a patent proximal segment of stent ( true lumen ) with subsequent occlusion ( non - opacified ) of the remainder length of both stents ( likely false lumen ) with true lumen recanalization around the stents of reasonable caliber in spite of aggressive initial post dilation of the original stents which could have potentially caused the complete collapse of the true lumen ( fig .
similarly , at the origin of the pda , the previously placed stent was not opacified . however , an adjacent slender lumen of contrast was visualized again likely indicating true lumen recanalization around the stent ( fig .
a ) transverse and ( b ) curved planar reformation of the mid - right coronary artery , and ( c ) transverse and ( d ) curved planar reformation of the distal right coronary artery and proximal posterior descending artery .
these demonstrate unopacified stents ( arrows ) spiraling around the true lumen ( * ) of the right coronary artery and adjacent to the true lumen ( * ) of the proximal posterior descending artery .
the patient received further medical therapy and subsequently underwent two - vessel elective bypass grafting to the pda and pl branches with complete resolution of symptoms .
latrogenic coronary artery dissection is a rare but serious complication of percutaneous transluminal coronary angiography .
( 1 ) coronary artery dissection has been classified by the national heart , lung and blood institute ( nhlbi ) classification system for intimal tears as : type a - luminal haziness ; type b - linear dissection ; type c - extraluminal contrast staining ; type d - spiral dissection ; type e - dissection with reduced flow ; and type f - dissection with total occlusion .
( 4 ) parallel wire techniques have been described in the setting of chronic total occlusion stenting and for management of rca dissections .
( 3 - 4 ) in a case series by chai et al . , 18 cases of extensive anterograde and retrograde coronary artery dissection were described out of 12,600 patients ( 0.14% ) ( 3 ) .
single wire technique was able to enter the true lumen in 8 patients and a double wire technique was used for 8 patients ; in 2 patients the procedure was not successful ( 3 ) .
the double wire technique involved placement of a single wire into the false lumen to seal the entrance and a second wire was used to enter the true lumen ( 3 ) .
the first and most basic is the risk that gentle or no injection of contrast into a dissected vessel to reduce further propagation ( hydraulic dissection ) of dissection in a distal fashion often makes it impossible to complete the procedure . in fact , in this case , although the first injection to visualize the rca was gentle , it did propagate the dissection further into the posterolateral vessel . however , fortunately , it allowed perforation of contrast back into the true distal posterolateral vessel , allowing the procedure to be completed at least as far as acute infarct rescue is concerned .
the initial wiring was performed at a distance from the ostium of the rca as this dissection was visualized to spread as both antegrade and retrograde towards the rca ostium at the aortic take - off .
distance wiring may have helped to initially enter the true lumen of the rca as guide catheter engagement may often be directly into the false lumen preventing true lumen wiring .
the false lumen , however , in the mid - rca was extremely large causing complete obliteration of the true lumen preventing it being wired further . in this emergency setting , our plan was to perform true - false - true lumen stenting to restore flow .
however , ultimately , although proximal and mid - body stenting was performed in the main rca as well as ostial pda stenting , it is likely that residual false lumen and non - visible dissection was left distal to the stents and proximal to the crux of the rca .
it is entirely possible that there was remodeling and slow thrombosis of this distal rca false lumen with subsequent occlusion of the more proximal stents due to possible thrombosis of the ensuing false lumen run off .
we suspect this may have happened slowly as enough time was provided to recanalize the true lumen without intervening infarction .
a similar process likely occurred in the pda branch as there was residual focal non - flow limiting dissection in the mid - pda beyond the false lumen implanted stent with incomplete coverage of the dissection length .
the authors have not seen any previously reported cases of entire true lumen vessel recanalization to this extent , in spite of long lengths of false lumen stenting even with aggressive post dilation of the stented false lumen .
although true lumen wire placement in the mid - distal rca was attempted in the original procedure , this was not possible given the essential complete obliteration of the true lumen due to false lumen compression .
have previously reported a side by side stenting beside an occluded false lumen stent mistakenly delivered in a chronic total occlusion with subsequent wiring and stenting of the true lumen in a later procedure ( 5 ) . in our case , this was not possible due to the connection of true and false lumens occurring through the side struts of a proximal stent in a helical fashion .
although with aggressive techniques it may have been possible to crush the previous false lumen stents and enlarge the current true lumen of the mid - rca , this would have had to be repeated at the level of the pda as well in a much smaller caliber vessel with a likely poor end result .
this approach was not , therefore , pursued and medical and surgical approaches were considered to be safer . the importance and utility of multimodality imaging , in our case with gated cardiac ct , is demonstrated as this can clarify the course of the true and false lumens and act as an accurate adjunct to coronary angiography .
in this case report , we present a patient with iatrogenic type f catheter induced spiral dissection of the right coronary artery with intentional false lumen stenting of the mid and distal rca and pda . probably due to remodeling and collapse of residual false lumen , the subsequent recanalization and expansion of surrounding true lumen as well as helical stent occlusion around it ,
aww , drafted and reviewed the manuscript ; ik , drafted and reviewed the manuscript , provided ct images ; km , mk , reviewed the manuscript ; am , reviewed the manuscript ; fh , drafted and reviewed the manuscript .
Output:
| guide catheter induced dissection of coronary arteries is an uncommon , but serious complication of coronary angioplasty .
treatment can include emergent coronary artery bypass grafting to the affected vessel or percutaneous intervention including wiring the true lumen and exclusion stenting of the dissection flap to prevent further propagation .
detailed descriptions have been published of techniques of intentional passage of guide wires into the false lumen and reentry into the true lumen with chronic total occlusions .
we present an unusual case of what appeared to be successful intentional false lumen stenting with reentry into the true lumen of an iatrogenic dissection of the right coronary artery with restoration of timi iii coronary flow which , one year later , was complicated by recanalization of the true lumen and occlusion of the stented false lumen causing symptomatic angina . |
PubmedSumm118713 | ***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: gemcitabine is a commonly used antineoplastic agent that is a nucleoside analog and pyrimidine antimetabolite that inhibits rna synthesis.1 it is most commonly used in solid organ malignancies such as nonsmall cell lung cancer , and breast , ovarian , and pancreatic cancer , although is also used in diffuse large bcell lymphoma in relapsed or refractory elderly patients.2 it has rare cardiac side effects including acute myocardial infarction , but is not well known to cause cardiomyopathy .
a 67yearold woman with past medical history significant for follicular lymphoma with transformation to diffuse large b cell lymphoma status post multiple cycles of chemotherapy complicated by transient left ventricular systolic dysfunction presented with sensation of throat closing and difficulty breathing upon completion of cycle 2 of rituximab plus gemcitabine and oxaliplatin ( rgemox ) .
her follicular lymphoma was initially diagnosed in 2007 and treated with rituximab , cyclophosphamide , doxorubicin , and vincristine ( rchop ) .
prior to initiation of chemotherapy , her left ventricular ejection fraction ( lvef ) was normal .
her only risk factor for cardiovascular disease was hyperlipidemia ( total cholesterol 248 mg / dl , ldl 171 mg / dl ) ; with no known hypertension , diabetes , or family history of coronary disease , and a normal exercise nuclear stress test . in 2010 ,
her cancer transformed to diffuse large b cell lymphoma ( dlbcl ) requiring autologous stem cell transplant .
she was then treated with rituximab , ifosfamide , carboplatin , and etoposide ( rice ) .
her disease remained in remission until 2013 . at that time , a left groin biopsy revealed recurrent dlbcl .
she was placed on bretuximab / rituximab , but once her disease progressed on this regimen , she was transitioned to rituximab , dexamethasone , cytarabine , and platinol ( rdhap ) .
one month into treatment with rdhap , the patient 's echocardiogram showed severely depressed lvef ( 2530% ) with global hypokinesis .
rdhap was discontinued , and a repeat echocardiogram 3 months later showed an improved lvef to 3540% ( figure
1 , table
1 ) .
all ejection fractions were determined by visual estimation . ejection fraction over time . chemotherapy agent by year , drug class , and frequency of cardiac adverse event rituximab , gemcitabine , oxaliplatin .
one month later , the patient presented to the hospital with sensation of throat closing and difficulty breathing .
she was admitted with suspicion of laryngospasm from oxaliplatin . upon further questioning , since initiation of rgemox , the patient noted exertional dyspnea and fatigue .
she was previously able to walk three to four laps around her local shopping mall although now endorsed dyspnea upon ambulation to the nearby bathroom . on examination
, she was found to have a new oxygen requirement and a 7 pound weight gain .
her jugular venous pressure was elevated with diminished bibasilar lung sounds and 2 + pitting edema of the lower extremities .
transthoracic echocardiogram revealed an lvef of 20% with global free wall hypokinesis and severe mitral regurgitation .
repeat echocardiogram 6 months later showed an improved lvef of 40% and mild mitral regurgitation .
our patient was exposed to multiple chemotherapy agents with known cardiotoxicity , and her ejection fraction therefore fluctuated throughout the course of her treatment .
cardiomyocytes , as well as other cell types comprising the heart , have a limited capacity for repair after sustaining injury from one agent or another . perhaps , the most cogent example of the multiple hit hypothesis is found in cardiotoxicity occurring after chemotherapy for her2/neuamplified breast cancer . when administered alone ,
the antiher2/neu monoclonal antibody trastuzumab is associated with a low incidence of subsequent left ventricular contractile dysfunction , in the range of 46%.3 however , when administered after an anthracyclinebased adjuvant regimen , the incidence of left ventricular systolic dysfunction is as high as 28%.3 the most plausible explanation for this finding is that when anthracyclineinduced cardiomyocyte injury occurs , the limited ability of cardiomyocytes to repair this damage is abrogated by the subsequent administration of trastuzumab , which , by inhibiting her2/neudependent signalling ( including phoshoinositide 3kinase / akt ) in the cardiomyocyte , inactivates cell survival pathways .
our patient was initially exposed to doxorubicin at a total cumulative dose of 450 mg / m .
the mechanism of cardiotoxicity here involves disruption of topoisomeraseiimediated dna repair and generation of oxygenderived free radicals.4 , 5 , 6 , 7 serial echocardiograms during several years after doxorubicin administration showed stable lvef .
the fact that her lvef fluctuated , rather than displaying a secular downtrend , in her later course is more consistent with acute cardiomyocyte injury following administration of individual agents , and not with chronic anthracyclineinduced left ventricular systolic dysfunction which is irreversible .
three years after treatment with doxorubicin , the patient was exposed to cyclophosphamide at the time of her stem cell transplant .
cyclophosphamide can cause endothelial and myocyte injury mediated through its toxic metabolic phosphoramide mustard that leads to dna crosslinking and subsequent apoptosis.4 the patient was then exposed to rdhap , of which , cisplatin has been shown to cause congestive heart failure , particularly in the elderly .
its mode of toxicity involves crosslinking with purine bases on the dna and thus interfering with dna repair mechanisms , causing dna damage and cell apoptosis.4 , 6
following cessation of rdhap , and prior to initiation of gemox , our patient 's lvef improved to 3540% .
oxaliplatin , although commonly known for many side effects including laryngospasm ( for which the patient was likely initially referred for hospitalization ) , peripheral neuropathy , and ototoxicity , is not associated with cardiomyopathy .
the coadministration of this agent with intravenous fluids may have contributed to volume overload . however
, this alone would not explain the abrupt development of acute kidney injury , lactic acidosis , and pronounced drop in ejection fraction .
acute kidney injury and lactic acidosis resolved with intravenous diuresis . upon cessation of gemcitabine , the patient 's lvef improved to 40% , near her baseline prior to initiation of all chemotherapy agents .
most of these report supraventricular tachycardias including atrial fibrillation.8 , 9 atrial fibrillation is typically seen 1824 h of infusion .
this side effect is likely because of a gemcitabine metabolite , 2,2difluorodeoxyuridine ( difdu ) , which has a an equivalent halflife of approximately 1824 h similar to the time of onset of atrial fibrillation.8 , 9 several case reports have demonstrated acute myocardial infarction acutely postgemcitabine infection secondary to druginduced vascular injury or endothelial damage.10 , 11 , 12
of all the possible cardiac toxicities , cardiomyopathy appears to be the least reported . in phase
i clinical trials of gemcitabine use , significant reduction in lvef occurred in 0.2% of patient , whereas 0.41.7% of patients developed cardiac arrhythmias.13 review of the literature of phase ii clinical trials of approximately 979 patients revealed 0.2% arrhythmias , 0.4% cardiomyopathies , and 0.2% with exudative pericarditis.14 in these trials , patients who developed cardiomyopathies had underlying coronary artery disease , whereas our patient had no history of coronary disease .
outside of clinical trials , gemcitabineinduced cardiomyopathy has been reported only once in the literature.2 the patient described was similar to ours .
he did not have prior coronary artery disease or risk factors . as with our described case ,
the patient presented with signs and symptoms of congestive heart failure after the second cycle of gemcitabine for pancreatic cancer .
the patient 's lvef at the time of presentation with symptoms of exertional dyspnea was noted to be 1520% with findings of global hypokinesis in addition to functional mitral regurgitation .
gemcitabine was discontinued , and two months later an echocardiogram showed recovery of lvef to 40% and resolution of mitral regurgitation .
we propose a multiple hit mechanism that ultimately led to a severely depressed lvef in our patient .
the delayed toxicity of doxorubicin , in combination with the direct cytotoxic effects and apoptosis seen with cyclophosphamide , led to her initial drop in lvef.4 , 15 subsequent exposure to cisplatin in may 2014 further damaged dna repair mechanisms and quickly depressed our patient 's lvef to 25% . upon discontinuation of cisplatin ,
it was not until the administration of gemcitabine in november 2014 that her lvef once again decreased to 25% .
the primary message of our report is that the administration of multiple cytotoxic cancer treatments , each with a different mechanism of action , can result in major cardiotoxicity despite being given in doses that for each individual agent may not be cardiotoxic . in the era of combination chemotherapy employing multiple chemotherapeutic drugs , it is important to recognize that an interaction may exist between the effects of individual agents resulting in cardiac dysfunction that is either unexpected or more severe than expected .
this case highlights a multiple hit mechanism of cardiomyocyte damage that may occur when employing multiple cardiotoxic agents in doses that , individually , may not be associated with cardiotoxicity .
Output:
| abstractgemcitabine is a commonly used antineoplastic agent used to treat a variety of cancers with rarely reported cardiac side effects .
we describe a case of a 67yearold woman with follicular lymphoma who experienced a rarely reported side effect of gemcitabine : cardiomyopathy .
this case highlights a multiple hit mechanism of myocyte damage that may occur following the use of multiple cardiotoxic agents despite their administration in doses not associated with cardiotoxicity . |
PubmedSumm118714 | ***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: oral cancer is significant component of the global burden of cancer affecting more than 400,000 individuals per year worldwide .
it is the most common neoplasm in india and most southeast asian countries , the high incidence of which has been attributed to the prevalence of tobacco chewing among the populations of these countries .
based on the increasing incidence of head and neck cancers , problems associated with late diagnosis , and the public health dilemma they represent , it would seem prudent to enact screening protocols to check at - risk people .
early diagnosis would allow for conservative therapeutic approaches with a brief recovery and a more favorable prognosis .
one aspect of cancer research that has intrigued most scientists is the acquisition of unlimited proliferative potential of cancer cells . in the process of transformation of a cell from normal state to malignant ,
telomerase is an rna - dependent dna polymerase that synthesizes telomeric dna fragments de novo , using its rna moiety as a template , and compensates for the loss of telomere during the cell division .
telomeres are specialized heterochromatic structures at the ends of vertebrate chromosomes that have been implicated in stabilizing and protecting the chromosomes , anchoring chromosomes within the nucleus , and assisting the replication of linear dna .
approximately 50200 bp of telomeric dna in somatic cells is lost on each population doubling , which is implicated in the control of the life span .
telomerase is active in embryonal and germ line cells but remains silent in most differentiated somatic cells .
loss of telomerase activity ( ta ) has been correlated with cellular senescence whereas its reactivation may be prerequisite for the development of malignant tumor cells from somatic cells .
oral squamous cell carcinoma ( oscc ) shows highest ta while oral potentially malignant lesions have relatively lower ta .
in addition , telomerase has been found to be upregulated according to tumor progression and may , therefore , serve as a useful prognostic indicator in identifying the patients in need of a close follow - up and vigorous adjuvant treatment .
moreover , telomerase is an important target for the design of therapeutic agents that might have minimal side effects .
most of the previous studies on ta in oscc have qualitatively assessed ta positivity rates or semiquantitatively evaluated relative ta .
the present study aims at quantification of ta in oscc and normal oral mucosal tissue and comparison of the same .
in addition , correlation of ta with clinical disease status and pathologic features such as tumor differentiation is investigated to evaluate the clinical significance and validity of ta as useful biomarker not only for early detection of cancer but also in prognosis of oscc .
the study group comprised 45 histopathologically proven cases of oscc and the control group comprised 20 normal oral mucosal samples obtained from healthy individuals who underwent surgical extraction of impacted third molars .
patients who had previously undergone or were under any form of therapy for oscc , patients suffering from recurrence of oscc , and patients on long - term nsaids or corticosteroid therapy ( known to inhibit ta ) were excluded from the study . demographic data and clinical details of each patient
sixty - five fresh tissue specimens obtained from oral cavity were immediately placed in rna stabilizing reagent and frozen for cell extract preparation .
the study protocol was divided into three major steps rna extraction , telomeric repeat amplification protocol ( trap ) assay , and gel electrophoresis .
the tissue specimens placed in rna stabilizing reagent and frozen were washed twice in cold phosphate - buffered saline ( pbs ) by adding 500 l pbs to the sample placed in microfuge tube and centrifuging at 5000 g for 1 min .
the tissue specimens were then treated with 1 ml lysis buffer and incubated on ice for 30 min .
cell debris was pelleted ( 12,000 g for 30 min at 4c ) , and the supernatant was collected and frozen at 80c for future use .
aliquots of extracts containing 20 g protein were used for each trap assay . trap assay for test reactions ( oscc and normal oral mucosa samples )
a volume of 2.5 l of cell extract was mixed with 1 l of cx reverse primer and 6.5 l of diethylpyrocarbonate ( depc ) to make the volume of the rna primer mix to 10 l .
the above mix was incubated at 65c for 10 min and immediately chilled on ice .
master mix was prepared by adding the components in the following order : 200 l of reaction mix provided in the kit was added , followed by 16 l each of ts forward primer and enzyme mix , respectively .
finally , 16 l of depc water was added to complete the master mix composition .
15.5 l of this master mix was added in each polymerase chain reaction ( pcr ) tube having 10 l of rna primer mix . in the second step
, the telomerase - synthesized new oligonucleotides were amplified using pcr by including reverse cx primer in the presence of deoxynucleotide triphosphates .
the above - prepared final mix was placed in a thermocycler in which three - step pcr was performed .
the cycle conditions were 42c for 30 min followed by 94c for 15 min for denaturation process .
the annealing step comprised 36 cycles of 94c for 30 s , 58c for 30 s , and 72c for 30 s. following the annealing step , extension was done at 72c for 5 min and 4c for 1 min .
the products of reaction were removed from thermocycler and stored at 4c for gel electrophoresis .
control reaction which was later used as internal standard for comparison of ta was repeated at several dilutions ( 1:2 , 1:5 , 1:10 , 1:25 , and 1:50 ) of control rna template . after 7 l of bromophenol blue dye
was added to each tube containing the pcr product , the products of the reaction ( 10 l of each ) were resolved by electrophoresis in a 12% nondenaturing polyacrylamide gel containing ethidium bromide , in 10x tae ( tris acetate ethylenediaminetetraacetic acid ) .
ten microliters of control reaction pcr products in the above - mentioned several dilutions were also resolved on the gel .
the minimum dilution of control reaction at which detectable activity could be appreciated was 1 g .
therefore , for each run of test reactions , a control reaction pcr product ( 1 g ) was included for later comparison .
after separation of products in ladder pattern , the gel was removed and wet gel was scanned directly using 254 nm ultraviolet transilluminator [ figure 1 ] .
ethidium bromide that had bound specifically to nucleic acids depending on the molecular weight and concentration of the nucleic acid was excited by ultraviolet irradiation , and on excitation , it emitted fluorescent light which was captured by built - in camera .
the bar diagram depicts the mean quantified telomerase activity in oral squamous cell carcinoma and normal mucosa total lab phoretic software ( nonlinear dynamics limited , uk ) was used for gel analysis .
the sum of total integrated fluorescence intensities of telomerase ladders in each gel lane from test reaction was divided by the signal from the co - amplified internal standard ( control rna reaction ) to get quantified telomerase levels .
since the ta of control rna template was 1 g , this was considered as the cutoff value .
the test reactions showing ta levels of > 1 were considered positive and those showing ta levels of < 1 were considered negative .
ta levels were compared between oscc and normal oral mucosa using student 's t - test .
the relationship between the level of ta and clinicopathologic factors such as age , sex , adverse habits , intraoral site of the lesion , size of the lesion , lymph node status , stage of the disease , and histopathologic grade was analyzed .
student 's t - test and anova test were applied to validate the significance of the difference between groups .
pairwise comparison among the who grades of malignancy and ta levels was done by tukey 's post hoc procedure .
the tissue specimens placed in rna stabilizing reagent and frozen were washed twice in cold phosphate - buffered saline ( pbs ) by adding 500 l pbs to the sample placed in microfuge tube and centrifuging at 5000 g for 1 min .
the tissue specimens were then treated with 1 ml lysis buffer and incubated on ice for 30 min .
cell debris was pelleted ( 12,000 g for 30 min at 4c ) , and the supernatant was collected and frozen at 80c for future use .
trap assay for test reactions ( oscc and normal oral mucosa samples ) consisted of two steps .
a volume of 2.5 l of cell extract was mixed with 1 l of cx reverse primer and 6.5 l of diethylpyrocarbonate ( depc ) to make the volume of the rna primer mix to 10 l .
the above mix was incubated at 65c for 10 min and immediately chilled on ice .
master mix was prepared by adding the components in the following order : 200 l of reaction mix provided in the kit was added , followed by 16 l each of ts forward primer and enzyme mix , respectively .
finally , 16 l of depc water was added to complete the master mix composition .
15.5 l of this master mix was added in each polymerase chain reaction ( pcr ) tube having 10 l of rna primer mix . in the second step ,
the telomerase - synthesized new oligonucleotides were amplified using pcr by including reverse cx primer in the presence of deoxynucleotide triphosphates .
the above - prepared final mix was placed in a thermocycler in which three - step pcr was performed .
the cycle conditions were 42c for 30 min followed by 94c for 15 min for denaturation process .
the annealing step comprised 36 cycles of 94c for 30 s , 58c for 30 s , and 72c for 30 s. following the annealing step , extension was done at 72c for 5 min and 4c for 1 min .
the products of reaction were removed from thermocycler and stored at 4c for gel electrophoresis .
control reaction which was later used as internal standard for comparison of ta was repeated at several dilutions ( 1:2 , 1:5 , 1:10 , 1:25 , and 1:50 ) of control rna template .
after 7 l of bromophenol blue dye was added to each tube containing the pcr product , the products of the reaction ( 10 l of each ) were resolved by electrophoresis in a 12% nondenaturing polyacrylamide gel containing ethidium bromide , in 10x tae ( tris acetate ethylenediaminetetraacetic acid ) .
ten microliters of control reaction pcr products in the above - mentioned several dilutions were also resolved on the gel .
the minimum dilution of control reaction at which detectable activity could be appreciated was 1 g .
therefore , for each run of test reactions , a control reaction pcr product ( 1 g ) was included for later comparison .
after separation of products in ladder pattern , the gel was removed and wet gel was scanned directly using 254 nm ultraviolet transilluminator [ figure 1 ] .
ethidium bromide that had bound specifically to nucleic acids depending on the molecular weight and concentration of the nucleic acid was excited by ultraviolet irradiation , and on excitation , it emitted fluorescent light which was captured by built - in camera .
the bar diagram depicts the mean quantified telomerase activity in oral squamous cell carcinoma and normal mucosa
total lab phoretic software ( nonlinear dynamics limited , uk ) was used for gel analysis .
the sum of total integrated fluorescence intensities of telomerase ladders in each gel lane from test reaction was divided by the signal from the co - amplified internal standard ( control rna reaction ) to get quantified telomerase levels .
since the ta of control rna template was 1 g , this was considered as the cutoff value .
the test reactions showing ta levels of > 1 were considered positive and those showing ta levels of < 1 were considered negative .
ta levels were compared between oscc and normal oral mucosa using student 's t - test .
the relationship between the level of ta and clinicopathologic factors such as age , sex , adverse habits , intraoral site of the lesion , size of the lesion , lymph node status , stage of the disease , and histopathologic grade was analyzed .
student 's t - test and anova test were applied to validate the significance of the difference between groups .
pairwise comparison among the who grades of malignancy and ta levels was done by tukey 's post hoc procedure .
the results of the present study showed ta in 89% of oscc and 5% of normal oral mucosa .
the ta levels ranged from 0.28 to 6.91 ( mean 2.05 , standard deviation [ sd ] 1.33 ) in oscc and 0.21 to 1.09 ( mean 0.54 , sd 0.27 ) in normal oral mucosa .
ta level differed significantly between oscc and normal oral mucosa ( t = 4.9691 , p = 0.0000 ) [ figure 1 ] . on comparison of ta activity with clinical and pathological parameters
, it was found that there was a statistically significant difference in ta levels between patients above 50 years and above and below 50 years of age ( p = 0.0298 ) .
the student 's t - test did not show statistically significant difference in the mean ta levels among males and females , among patients with or without adverse habits , and also did not differ among groups with different types of tobacco habits .
significant difference in ta levels at different primary site of oscc was not observed such as tongue and buccal mucosa .
ta levels increased slightly but not significantly with progression from t3 to t4a and t4b .
the ta levels in t3 + t4 disease were slightly but not significantly higher than that in t1 + t2 disease ( p = 0.1060 ) .
ta levels in patients with regional lymph node metastasis ( n1 + n2 ) were slightly but not significantly higher than n0 disease ( p = 0.3623 ) . a statistically significant difference in ta according to overall clinical stage was not observed in the present study ( p = 0.2703 ) .
furthermore , statistically significant differences between early stages ( i + ii ) and late stages ( iii + iv ) were not observed in the present study with the p value being 0.8621 [ table 1 ] .
anova test for comparison of telomerase activity levels among clinical stages oral squamous cell carcinoma a higher histological grade of malignancy in who classification was associated with a higher ta level [ table 2 ] and the difference was statistically significant ( p = 0.0000 ) .
anova test for comparison of telomerase activity levels among who classification of grades of oral squamous cell carcinoma
the telomere hypothesis of cancer cell immortalization remains an attractive concept and ta in human oral cancer is a subject of great interest .
the highly sensitive pcr - based trap assay provides the means to analyze ta in a wide variety of tissues .
this method makes it possible to detect ta in a very small number of cells which is a major advantage for examining clinical specimens .
the overall prevalence of 85% among more than 3000 human tumor samples tested using trap assay makes the ta the most universal marker for human cancers .
the diagnostic and prognostic potential of telomerase could contribute to improving the outcome of patients with oscc .
although the incidence of oscc is so high , ta in this tumor has not been extensively studied .
there are several reports from all over the world and only a few from india , but the data remain limited .
in addition , most of the previous literature is limited to qualitative or semiquantitative estimation of ta . in order for cells to gain the ability to proliferate excessively and
the present study was aimed at quantitative detection of ta in normal oral mucosal tissue and oscc .
we investigated the clinical significance of telomerase activation in head and neck cancer patients in india .
ta was detected in 89% of oscc samples as compared to 5% of normal oral mucosal samples .
this is in accordance with previous studies in which ta detected in head and neck squamous cell carcinoma ( hnscc ) has ranged from 75% to 100% of the samples investigated .
califano et al . , liao et al . and koscielny et al . in their studies have demonstrated ta of < 85% in hnscc .
, curran et al . , sumida et al . , miyoshi et al . , and fujita et al .
thurnher et al . detected ta in 100% of oscc samples in their study . among the three studies conducted in the indian population , kannan et al . and patel et al . have reported ta of 75% , 80% , and 72.8% in oscc , respectively .
these results suggest that telomerase is activated in oscc and this is in keeping with the concept that the enzyme plays a key role of telomere maintenance in carcinogenesis .
however , it was also noted that the acquisition of ta was not an obligate pathway for oral carcinogenesis since 11% oscc lacked this activity .
the telomerase negative samples may exhibit alternative lengthening mechanism of telomere maintenance in form of chromosome maintenance or other uncharacterized mechanisms .
, sumida et al . , chang et al . , and miyoshi et al . have not reported any detectable ta in normal tissues , liao et al .
, xian et al . , and fujita et al . have made a distinctive observation of the presence of weak ta in normal samples .
the telomerase positivity rates in these studies have ranged from 2.78% to 100% for normal samples .
the reason for telomerase positivity in one of the normal oral mucosal samples in the present study may be related to stratification and complex differentiation pattern of squamous epithelium .
squamous epithelium has very high cell turnover rate , and the constant loss of superficial cells by the process of desquamation is replaced by continuous division in the basal cells .
hence , comparatively more stem cells are likely to be present in the squamous epithelium for the active self - renewal process . as in the case of immortalized cells ,
cellular kinetic studies have also revealed a similarity in cell proliferation pattern between the stem cells of squamous epithelium and hematopoietic tissues .
thus , the ta in normal oral mucosa may be due to the presence of stem cells . however , bickenbach et al .
have reported that epidermal stem cells were not the major source of ta and demonstrated that proliferating transit - amplifying cells exhibited more active telomerase .
it has also been demonstrated that a normal hematopoietic cell lineage has weak ta and that the telomere shortening occurred in the hematopoietic cell lineage which is subject to aging , implying that the level of ta in those cells may be insufficient for the prevention of telomere erosion .
a similar process may be present in oral epithelium which might be responsible for weak ta . in
the present study , quantification of ta in oscc and normal oral mucosal samples showed a statistically significant difference between ta of oscc ( 2.05 ) and normal oral mucosa ( 0.54 ) .
these results are in accordance with previous studies by fujita et al . and yajima et al .
our preliminary results indicate that ta may be a valuable marker for diagnosis of oscc . in this study ,
the wide distribution of ta is attributed to the mechanism of immortalization involving factors other than telomerase activation .
in addition , possibility of mesenchymal tissue contamination , lymphoid proliferation , and necrotic tissue contamination has to be considered .
considered the possibility of contamination by mesenchymal tissue and necrotic lesions which might affect telomere extension and pcr and thereby influence results of ta assay .
since ta was reported in normal hematopoietic cells , we also looked for any differences in inflammatory cell infiltration in telomerase - negative and telomerase - positive lesions with routine histopathological examination .
no significant difference between these groups with regard to inflammatory cell infiltration was observed because the telomerase - negative lesions also had marked inflammatory cell infiltration , similar to telomerase - positive lesions .
telomerase is a highly stable ribonucleoprotein complex , half - life of which is over 20 h in vivo .
therefore , samples obtained by biopsy or during surgery or autopsy can be analyzed by the trap assay .
however , in case of oral lesions , contamination by bacteria , plaque material , saliva , and blood may complicate the results . in our study
, we analyzed ta in tissue sections immediately adjacent to sections for which histological features were reviewed by bisecting the clinical specimen into two parts . using this technique
, we were able to compare ta in tumors and adjacent tissues with their precise histological features .
. a higher histological grade of malignancy in who classification was associated with a higher ta level .
it has been reported that who grade i oscc are slow - growing , compared with grade ii and iii oscc , which are also more aggressive in nature .
it is likely that less differentiated oscc ( grades ii and iii ) might contain more immortal cells than the more differentiated histological type ( grade i ) ; hence , ta would also be high .
the presence as well as the absence of a relation between ta and the who classification has been reported previously . a semiquantitative analysis performed by kannan et al . revealed high ta levels in 10 ( 29.4% ) of 34 well - differentiated oscc lesions and 7 ( 100% ) of 7 moderately to poorly differentiated oscc lesions , suggesting that a lower histological grade of differentiation is associated with higher ta .
the results of semiquantitative assay by sumida et al . indicated that grade iii oscc possessed higher ta than grade i oscc . however , miyoshi et al . reported the absence of such a relationship .
however , they analyzed 19 grade i lesions but only 1 grade ii and 1 grade iii lesion ; therefore , their results may not support the absence of a relation between ta and tumor grade .
found that relative ta varied widely among grades ii and iii lesions , with no significant difference .
however , most grade i lesions had low relative ta and ta level differed significantly between grades i and iii and between grades i and ii + iii , in their study .
the available data indicate that telomerase may be associated with increased cancer cell atypia and mitotic figures and structural changes of cancer tissue .
telomerase reactivation is a necessary and rate - limiting step of cellular immortalization and could provide a unique marker of aberrant cells , which may selectively be targeted . although telomerase was initially considered a specific marker of malignancy , weak activity of normal tissue can lead to false - positive results .
a quantitative telomerase assay that can distinguish between normal tissue and malignancy is , therefore , required . because of this expression pattern , testing for ta may deliver useful diagnostic information about clinical tumor behavior .
it can be concluded from the current study that enhanced expression of ta occurs during human oral carcinogenesis and supports the critical role of telomerase in the development of human oral cancer .
ta levels showed no correlation with clinical parameters such as sex of the patient , history of adverse habits , site of the lesion , size of the lesion , lymph node involvement , or overall stage of the patient .
however , significant correlation with age of the patient and histopathological grades of malignancy was observed in the present study .
thus , ta can be an additional tool , as a biomarker , for assessing the prognosis or biological grade of the oral carcinomas .
Output:
| background and objective : the role of telomeres and telomerase in oral cancer is an area of much recent interest .
the understanding of the role of telomere biology , the end replication problem leading to genomic instability and the reactivation of telomerase , is absolutely critical to our understanding of oral cancer , and more so , to our ability of early diagnosis and developing novel therapies and cancer prevention approaches .
the aim of the present study was to quantify telomerase activity ( ta ) in oral squamous cell carcinoma ( oscc ) and normal oral mucosa and assess the role of telomerase as diagnostic and prognostic marker of oral malignancy.materials and methods : we quantified ta in 45 patients with oscc and 20 normal oral mucosal specimens using polymerase chain reaction - based telomeric repeat amplification protocol assay and compared it with the clinical status and grade of malignancy.results:ta was detected in 89% of malignant and 5% of normal oral mucosal tissue .
the ta levels ranged from 0.28 to 6.91 ( mean 2.05 , standard deviation [ sd ] 1.33 ) in oscc and 0.21 to 1.09 ( mean 0.54 , sd 0.27 ) in normal oral mucosa .
there was no relationship between ta levels and clinical stages , site of the lesion , history of adverse habits , or sex of the patient .
however , under the who classification , there were significant differences ( p < 0.00 ) between grades i , ii , and iii .
furthermore , increasing age of the patient significantly correlated with ta.interpretation and conclusion : the results of the present study indicate that activation of ta is frequent in oscc .
statistically significant difference in quantified telomerase levels of oscc and normal oral mucosa ( p < 0.00 ) demonstrates the significant clinical usefulness of telomerase activation as a valuable marker for diagnosis while significant correlation of ta with grades of malignancy indicates its effectiveness as marker for prognosis of oscc . |
PubmedSumm118715 | ***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: glaucoma is becoming more common than expected , which is characterized by loss of retinal nerve fiber layers and an associated change in visual field , resulting in irreversible blindness worldwide .
the total number of people aged 4080 years diagnosed as having primary open - angle glaucoma ( poag ) is predicted to increase to 79.76 million in 2040 , approximately 85% of the glaucomatous population .
the pathogenesis of open - angle glaucoma ( oag ) has not been fully interpreted yet and accumulating evidence suggests that it is associated with the reduced blood perfusion to the optic nerve [ 24 ] .
as the peripapillary choroid branches are the main source of blood supply to this region , it has been proposed that an abnormal choroid circulation could be involved in the occurrence of glaucomatous optic neuropathy .
however , it is specifically challenging to study because it is located beneath the retinal pigment epithelium ( rpe ) .
a precise clinical assessment of choroidal changes might be particularly important for an accurate interpretation of glaucoma .
prior to the improvements of optical coherence tomography ( oct ) , the choroid could only be evaluated by indocyanine green angiography ( icga ) , laser doppler flowmetry , and ultrasound , all of which are not sufficient to examine the choroid in detail .
optical coherence tomography offers the opportunity of providing a relatively detailed quantitative measurement tool for choroidal structure at a range of locations across the posterior pole with high - quality and cross - sectional images [ 8 , 9 ] .
an estimate of choroidal thickness can be obtained by determining the distance from rpe / bruch 's membrane interface to sclerochoroidal interface . with renewed interest in the potential role of the choroid in the pathophysiology of oag
, some recent studies have explored ppct measured by oct in oag patients , only to find conflicting results .
if ppct changes correlate with oag , evaluation of ppct would be particularly important , because earlier detection and better monitoring of glaucoma would minimize the risk of blindness . to determine whether ppct changes in oag patients or not
this updated meta - analysis was conducted under the guidance of the preferred reporting items for systematic reviews and meta - analyses ( prisma ) statement ( see checklist s1 in supplementary material available online at http://dx.doi.org/10.1155/2016/5484568 ) .
an initial systematic search of pubmed , embase , isi web of knowledge , and the cochrane library was conducted without language or time restrictions .
systematic searches were conducted using the following key words in different combinations : peripapillary choroidal thickness , optical coherence tomography , and open - angle glaucoma .
in addition , the reviewers also went through the reference lists of relevant published articles manually for any additional study .
published studies were included if they were in cross - sectional or case - control design comparing the differences in peripapillary choroidal thickness measured by oct between patients with oag and healthy controls .
abstracts from conferences , case reports , duplicate publications , letters , and reviews were excluded .
the extracted contents included the following : first author , publication year , location , oct type , study size , mean age , mean axial length , iop at imaging , and mean visual field md .
the peripapillary choroidal thickness parameters evaluated were average , superior , inferior , nasal , and temporal thickness .
superior choroidal thickness was defined as choroidal thickness measured at a certain location superior to the center of optic nerve head or the mean value of several different points in this sector .
similarly , we used this method to extract the inferior , nasal , and temporal choroidal thickness .
the newcastle - ottawa scale ( nos ) was employed in the quality assessment in our meta - analysis .
this quality scoring system ranging between zero up to nine stars contains three broad perspectives , divided into 8 items specifically .
two review authors subjectively scored each included study and any differences were resolved by discussion .
statistical analysis was performed using revman software ( version 5.3 ; cochrane collaboration , oxford , united kingdom ) .
as the ppct was continuous outcomes , the effect sizes were measured using the weighted mean difference ( wmd ) and 95% confidence interval ( ci ) .
we examined heterogeneity among the studies using the chi - square test and i test .
p < 0.05 for chi - square test or i > 50% represented the presence of obvious heterogeneity ; then a random - effect analysis model was used and subgroup analysis would be conducted . otherwise , the fix - effect analysis model was applied .
p < 0.05 represented a statistically significant difference for overall effect . to explore the stability and reliability of our results , we performed sensitivity analysis using stata ( version 14 ; statacorp , college station , texas ) .
this was conducted by deleting one study successively and recalculating the effect sizes of the remaining studies . in order to detect potential publication bias ,
meanwhile , begg 's and egger 's tests were also calculated for the primary outcome using stata ( version 14 ; statacorp , college station , texas ) .
the majority of these were excluded after the application of inclusion and exclusion criteria , mainly because most of them were not relevant to our analysis .
six studies were finally excluded for various reasons : three due to unqualified control groups ( two using glaucoma suspects [ 12 , 13 ] and one using the collateral nonglaucomatous eyes ) , one due to insufficient data which just provided the mean value without the sd , and the other two were meta - analyses [ 16 , 17 ] .
four were conducted in korea [ 1821 ] , 2 were conducted each in america [ 22 , 23 ] , japan [ 24 , 25 ] , and china [ 26 , 27 ] , and 1 was conducted in canada , germany , and belgium .
various oct instruments were applied in these studies , such as heidelberg ( heidelberg engineering , heidelberg , germany ) , rtvue-100 sd - oct ( optovue inc . ,
fremont , ca ) , cirrus hd - oct ( carl zeiss meditec , dublin , ca ) , and swept - source oct ( ss - oct ) .
with regard to the quality assessment , table 2 shows the quality score of each included article using the newcastle - ottawa scale .
all the studies had a score of 6 or higher , suggesting a low risk of bias .
there was significant heterogeneity in the analysis of average ppct between oag and the control group ( = 92.49 , p < 0.05 , i = 85% ) and random - effects model was applied .
the result showed that the average ppct in oag patients was reduced significantly compared to the healthy individuals ( wmd = 24.07 , 95% ci : 34.29 , 13.85 ) ( figure 2 ) .
moreover , ppct in each sector between the two groups was used for meta - analysis .
the results revealed that there was particularly apparent heterogeneity among these studies : superior ( i = 82% ) , inferior ( i = 95% ) , nasal ( i = 92% ) , and temporal ( i = 95% ) .
however , meta - analysis of each sector showed that a significant reduction of ppct between the two groups in the superior ( wmd = 28.87 , 95% ci : 44.96 , 12.78 ) and nasal ( wmd = 21.75 , 95% ci : 41.52 , 1.98 ) parts was identified , but ppct in the inferior ( wmd = 9.57 , 95% ci : 36.55 , 17.40 ) and temporal ( wmd = 13.85 , 95% ci : 35.40 , 7.70 ) sectors was not significantly different in oag patients compared to the control group ( figure 3 ) .
subgroup analysis was carried out according to the type of glaucoma and the result showed that there was a significant difference of average ppct between poag patients and controls ( wmd = 14.60 , 95% ci : 23.41 , 5.80 ) with no heterogeneity ( i = 15% ) ; similar result was observed in ntg patients ( wmd = 37.18 , 95% ci : 66.13 , 8.22 ) but with significant heterogeneity ( i = 92% ) ( figure 4 ) .
the data showed changes in ppct appeared to be correlated with poag as well as ntg .
there was no sufficient data to conduct further analysis for ppct in the 4 sectors .
figures 5 and 6 were generated to evaluate the influence of a single study on the pooled results , and the results did not change significantly when any particular study was removed , which confirmed the stability of the results .
because of the small sample sizes , we did not conduct further sensitivity analyses in the subgroup analysis . to assess the publication bias of the literature for average peripapillary choroidal thickness
publication bias was also calculated using begg 's test ( p = 0.499 ) and egger 's test ( p = 0.859 ) , and no obvious evidence of publication bias was found .
similar results were revealed in the analysis of each sector ( figure 8) , which did not reveal any asymmetry .
we did not conduct publication bias analyses in the subgroups analysis due to the small sample sizes .
with the mounting clinical evidence indicating the involvement of the peripapillary choroid in glaucoma , it has become increasingly important to detect changes of the choroid .
optical coherence tomography is a useful method for investigating anatomical parameters of the choroid with high reliability and reproducibility [ 31 , 32 ] .
although oct could not provide the exact hemodynamic physiology of choroidal circulation flow , it gives us better visualization of the choroid compared to previous instruments by the application of an enhanced depth imaging ( edi ) model [ 33 , 34 ] .
thinner peripapillary choroidal thickness is thought to be the result of loss of innermost choroidal vasculature and may be an anatomic risk factor for open - angle glaucoma , contributing to the progression of optic neuropathy . the ability to quantify these peripapillary choroid changes may allow enhancement of current models of initiation and progression of glaucoma . despite a large amount of studies exploring the relationship between oag and ppct
the data in this meta - analysis showed that the average ppct in oag was significantly reduced compared to healthy individuals which was a potential support of the vascular theory of glaucoma and suggested the retrobulbar ischemia might have an impact on the optic nerve head .
contrary to this , previous meta - analyses conducted by wang and zhang and zhang et al .
both demonstrated no correlation between ppct and oag . besides , we found that the choroid was thinner in the superior and nasal sectors of the optic disc in glaucoma eyes .
however , several studies have reported thinnest ppct in the inferior region in normal eyes and hypothesized that thinner choroid makes this area more vulnerable to glaucomatous ischemic damage , giving a possible explanation why glaucoma typically affects the inferior optic nerve area first [ 3537 ] .
as we all know , glaucoma is often manifested with focal optic disc damage ; none of these included studies addressed the morphological patterns of optic disc damage which might be highly related with the choroidal thickness around the optic nerve head .
further investigations focused on the relationship between the type of glaucomatous disc damage and the distribution of peripapillary choroidal thickness are required to address this problem .
subgroup analysis revealed that glaucoma type had a close connection with ppct which needed to be considered .
both poag and ntg showed significant difference in average ppct but with opposite heterogeneities , which probably indicated that reduction of choroidal thickness around the optic disc might play a part in the pathogenesis of ntg and poag , just in accordance with previous published studies showing reduced peripapillary choroidal circulation in patients with poag as well as ntg [ 3840 ] . with more and more quantitative techniques becoming available
, the debate over choroidal deficits in the pathophysiology of glaucoma will come to a consensus .
in contrast with the earlier meta - analyses conducted by wang and zhang and zhang et al . , we examined a wider range of clinically relevant outcome measures and focused on direct comparisons between oag and healthy controls after extending the date of literature search by one year .
wang and zhang included relatively limited studies ( n = 6 ) and zhang et al . actually included 10 studies when analyzing the relationship between oag and ppct .
three studies in the synthesis conducted by zhang et al . were not included in our analysis and the reasons were stated as follows .
hosseini et al . only measured the ppct at the point about 1000 microns from the temporal side of the optic disc border , roughly at the same location where the 3.46 mm circumpapillary rnfl measurement circle crosses the horizon linear scan .
such a specified location could not represent the average choroidal thickness around the optic disc , which may introduce bias in the synthesis .
examined 61 unilateral ntg patients and compared the ppct of the glaucomatous eyes with the contralateral normal eyes .
maul et al . reviewed 23 oag patients and 30 oag suspects . since the latter two used those with high possibility to develop glaucoma as the control groups , it is possible that no association was identified .
the above three were excluded and four refreshed studies were included after a stricter application of the inclusion criteria .
they compared 24 eyes with poag with 32 control eyes and found statistical thinning of average ppct as well as the choroidal thickness in each quadrant in poag patients .
finally , 13 studies involving 1067 eyes in the experiment group and 876 eyes in the healthy control group were included in our meta - analysis .
smaller sample sizes could increase the risk of making a falsely negative conclusion and apparently conclusive meta - analysis may be inconclusive .
therefore , we do have reasons to believe the changes of ppct might exist in oag .
although there are important discoveries revealed by these studies , there were several limitations in this meta - analysis .
first , studies included in our meta - analysis examined patients with variable types of oct instruments and different oct provided different scan methods .
also , the segmentations of the choroid were performed manually and the measurements were conducted at different locations .
although we had made a significant effort to select the most consistent data for analysis , we still could not completely exclude the measurement bias .
different oct instruments , different measurement points , and patient characteristics , such as race , sex , age , and axial length , may contribute to the heterogeneities in our meta - analysis .
we only conducted a subgroup analysis according to the type of glaucoma , which indicated that the type of glaucoma might be a risk factor influencing peripapillary choroidal thickness .
the remaining factors were too various to perform subgroup analysis or meta - regression which might explain the heterogeneities to a certain extent .
third , only published studies were included and no apparent evidence of publication bias was presented in our analysis ; however , unpublished studies and original data may be neglected ; thus a potential publication bias may exist .
additionally , not all potentially confounding factors such as diurnal fluctuation of ppct , medication treatments , and systematic vascular related diseases were reported among the included studies , which would increase the risk of bias .
the results based on the quantitative research synthesis suggest that further researches are required to better describe the relationship between different glaucoma patients and peripapillary choroidal thickness in detail . in a word ,
recent innovations in optical coherence tomography have helped to better visualize and quantitatively analyze the choroid effectively .
but the association between the choroidal thickness measured by optical coherence tomography and the choroid circulation has not been completely understood . as the technology continues to evolve ,
the combination of oct and angiography shows the potential to assess ocular hemodynamics and reveals that glaucomatous eyes have reduced peripapillary flow .
though so many uncertain and unpredictable factors may be involved , oct shows excellent prospects for the future research .
further ongoing advancements in technologies are desiderated and expected to explore the relationship between the choroid circulation and open - angle glaucoma in detail .
our meta - analysis indicated that average peripapillary choroidal thickness decreased in open - angle glaucoma .
the results also highlight that peripapillary choroidal thickness measured by optical coherence tomography may be an important parameter to consider in open - angle glaucoma .
Output:
| purpose . to investigate the potential relationship between open - angle glaucoma ( oag ) and peripapillary choroidal thickness ( ppct ) . materials and methods .
relevant publications were searched systematically through various databases from inception to january 2016 .
studies comparing ppct in oag patients and healthy controls were retrieved .
all qualified articles were analyzed using stata 14.0 and revman 5.3 software .
results .
a total of 13 studies were identified for inclusion .
there was a significant reduction of average ppct in oag patients compared to control participants ( wmd = 24.07 , 95% ci : 34.29 , 13.85 ) .
reduction of ppct was significant in the superior ( wmd = 28.87 , 95% ci : 44.96 , 12.78 ) and nasal ( wmd = 21.75 , 95% ci : 41.52 , 1.98 ) sectors , but there was no significant reduction of ppct in the inferior ( wmd = 9.57 , 95% ci : 36.55 , 17.40 ) and temporal ( wmd = 13.85 , 95% ci : 35.40 , 7.70 ) sectors .
no obvious publication bias was detected .
conclusions .
this meta - analysis suggests that open - angle glaucoma patients have significantly decreased peripapillary choroidal thickness compared to healthy individuals .
peripapillary choroidal thickness measured by optical coherence tomography may be an important parameter to consider in open - angle glaucoma . |
PubmedSumm118716 | ***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 orbit , like the maxillary antrum , is an anatomical region which is of clinical and surgical interest to many disciplines .
it may be regarded as crossroads where the signposts , in the more complex injuries , clearly indicate the necessity for additional expertise , which can be provided by other specialties .
all traumas to the face , particularly above the level of the mouth , require a careful ocular examination , including an estimation of the visual acuity of each eye .
however , other potentially blinding complications can easily be missed unless they are actively sought .
the initial examinations may be the only time that the physician is able to observe the damage to such structures such as the retina and optic nerve that may later become obscured by continued hemorrhage and cataract formation .
ophthalmic injuries in relation to maxillofacial trauma may be non - occupational domestic injuries , injuries in travel and sports , industrial hazards , assaults , self - inflicted injuries , and so on .
the injuries vary from lacerations of the lids and abrasions of the cornea to wounds or ruptures of the sclera , intraocular hemorrhages , dislocation of the lens , and detachment of the retina .
accidents involving the injury to the eyes and their adnexal incurred in traveling are common . in all traveling accidents , whether incurred in trains , airplanes , or car
, the injury tends to be severe , as a rule contusion leading to fracture of the orbit and rupture of the globe or penetrating injuries due to glass is associated with considerable facial damage , particularly lacerations of the eyelids and cheek .
the treatment of facial trauma is generally reported separately from the management of specific ocular trauma due to the fact that many surgeons who manage facial injuries are not ophthalmologists .
therefore , they are not aware of many types of ocular injuries that may occur as well as their diagnosis , appropriate therapy , and ultimate prognosis
. some ocular injuries may require concomitant surgical treatment with facial injuries , while in other circumstances the presence of an ocular injury would contraindicate immediate surgery to repair the facial fractures .
the objective of this study was to determine the incidence and types of ocular and motility disorders , as assessed by ophthalmologist , in patients who had sustained maxillofacial fractures and who were under the care of a maxillofacial surgeon .
this prospective study was conducted involving patients with a history of mechanical injury to the facial region .
all the patients with persistent pathology were followed up to a period of two years .
the study included 136 patients with confirmed facial fractures who presented during a seven - month period .
these included 71 midfacial fractures , 55 mandibular fractures , four nasal fractures , and six frontal fractures .
all the patients sustaining confirmed maxillofacial fractures were examined by an ophthalmologist for any associated ophthalmic injury .
all data accruing from each ophthalmic consultation were as follows : all routine information all ocular injuries sustained and their functional consequences , complications , treatment , and recovery .
examination of ocular motility comprised assessment of movement in all directions of gaze and elicitation of diplopia .
all motility abnormalities were quantified by means of prism cover test , the synoptophore , the field of binocular single vision , and/or the hess chart , as appropriate for the type of motility disorder detected .
enophthalmos was detected using the keeler frame in those patients in whom the orbital margin was intact .
examination from above with careful delineation of the position of the globe with respect to the supraorbital margin was carried out in all other patients . in almost all the cases , classical signs and symptoms of facial fractures were present and particular diagnosis was arrived at after a thorough examination following first aid , and was in most cases supported by x - rays and/or ct scans . following category of patients were excluded : where due to the patient 's serious general conditions following severe injuries , an adequate clinical and radiographic examination was not possible and often not required , patients with solitary fractures of the alveolar process ( inferior and/or superior ) or pure dental injuries ( subluxation , luxation , avulsion ) , patients with soft tissue injuries of the facial region , and patients with fractures who were treated as outpatients .
facial injuries were grouped as fractures of the facial skeleton involving mandible , mid - face , nasal , and frontal region .
ophthalmic injuries were classified into three categories after a thorough examination as mild , those injuries without permanent visual or physiologic sequelae , moderate , defined as those producing sustained visual loss or adnexal sequelae requiring subsequent reconstruction and severe to those injuries with no light perception .
all ocular injuries sustained and their functional consequences , complications , treatment , and recovery .
examination of ocular motility comprised assessment of movement in all directions of gaze and elicitation of diplopia .
all motility abnormalities were quantified by means of prism cover test , the synoptophore , the field of binocular single vision , and/or the hess chart , as appropriate for the type of motility disorder detected .
enophthalmos was detected using the keeler frame in those patients in whom the orbital margin was intact .
examination from above with careful delineation of the position of the globe with respect to the supraorbital margin was carried out in all other patients . in almost all the cases , classical signs and symptoms of facial fractures were present and particular diagnosis was arrived at after a thorough examination following first aid , and was in most cases supported by x - rays and/or ct scans . following category of patients were excluded : where due to the patient 's serious general conditions following severe injuries , an adequate clinical and radiographic examination was not possible and often not required , patients with solitary fractures of the alveolar process ( inferior and/or superior ) or pure dental injuries ( subluxation , luxation , avulsion ) , patients with soft tissue injuries of the facial region , and patients with fractures who were treated as outpatients .
facial injuries were grouped as fractures of the facial skeleton involving mandible , mid - face , nasal , and frontal region .
ophthalmic injuries were classified into three categories after a thorough examination as mild , those injuries without permanent visual or physiologic sequelae , moderate , defined as those producing sustained visual loss or adnexal sequelae requiring subsequent reconstruction and severe to those injuries with no light perception .
these included 71 mid - face fractures , 55 mandibular fractures , four nasal fractures , and six frontal bone fractures .
mid - face fractures included 36 zygomatic complex fractures the fractures involving the malar bone in isolation or in combination with other mid face fractures .
only six patients sustained isolated fractures of the lefort type while 18 others sustained lefort fractures in combination with other facial fractures .
fifty - five mandibular fractures included seven symphysis , 22 parasymphysis , 19 body , three angle , and four condylar fractures .
patients having facial fractures ranged in age from an 8-year - old boy to a 72-year - old male .
males accounted for 67.7% ( n = 92 ) of all facial fractures and females , 32.3% ( n = 44 ) .
the majority of the patients were between the ages of 10 and 50 years , with the peak incidence occurring in the 20- to 30-year - age group for both the sexes .
the major cause of maxillofacial trauma in this study was road traffic accidents , which accounted for 71.3% of all patients ( 97/136 ) .
the second most common cause was falls ( 15.4% or 21 patients ) , followed by assault5.8% or eight patients .
this was followed by sports ( 4.4% or six patients ) , industrial ( 1.4% or two patients ) .
table 1 shows the incidence of ophthalmic disorder in relation to the etiology of maxillofacial trauma after ophthalmological examination .
incidence of ophthalmic disorders in relation to the etiology of maxillofacial trauma fifty - five patients who sustained mandibular fractures were examined and 34.5% ( 19 of 55 ) sustained eye injuries .
four patients who sustained nasal fractures were examined and one ( 25% ) sustained eye injury .
seventy- one patients with mid - facial fractures were examined and 95.7% ( 68 of 71 ) had eye injuries54 were males and 14 were females .
six patients with frontal fractures were examined and 83.3% ( 5 of 6 ) had eye injuries three were males and two were females . the type of ophthalmic injury with respect to the location of the fracture , the seriousness of the injury , and the extent of visual disability were analyzed .
table 2 illustrates the incidence of eye abnormalities , according to their severity in the population of study .
table 3 illustrates the same in relation to the type of mid - facial fracture sustained .
ninety - three of the patients ( 68.3% ) examined sustained eye injuries of various types .
of these , 61.2% were temporary or minor , 29.03% were moderate , and 9.6% were serious .
minor ophthalmic injuries like eyelid swelling / bruising may cause subcutaneous palpebral hemorrhages which gradually absorb .
twenty - seven patients ( 29.3% ) suffered moderately severe ophthalmologic injuries ( 33 in number ) , examples of which include minor eyelid and conjunctival lacerations and enophthalmos .
eyelid and conjunctival lacerations require suturing with careful apposition of the wound edges using a fine suture material .
all lens injuries should be referred to the ophthalmologist , there being no urgency for treatment of pure lenticular injuries .
nine patients ( 9.6% ) sustained severe eye injuries such as retinal or vitreous injury or optic nerve damage .
of those nine patients , six patients ( 66.6% ) lost vision in the affected eye .
left eye was affected in 49 patients ( 49/93 = 52.6% ) . when a tear of the retina is present , specialized ophthalmic treatment is usually needed .
similarly , detachment of retina is accompanied by a corresponding visual field defect and requires specialist attention .
all blunt ophthalmic injuries require fundus examination within a week of the injury to exclude retinal tear and/or detachment .
severe injuries such as proptosis give little damage to the eye itself , provided it is reduced early .
incidence of ophthalmic disorder in the population of study incidence of ophthalmic disorder in relation to midfacial trauma ophthalmic disorders in relation to other fractures subconjunctival hemorrhage two - third of all the patients with orbital fracture suffered a severe ophthalmic injury ( 7/11 = 63.6% ) .
three of eight patients with lefort ii level fracture had severe ophthalmic injury , whereas lefort i level fracture was not associated with any severe ophthalmic injury .
sixteen mandibular fractures were associated with mild ophthalmic injury , whereas three were associated with moderate complications .
ct scan image showing orbital # twenty - seven of 93 patients ( 29.09% ) had suffered transient or permanent visual loss .
causes of impaired vision varied from minor self - healing corneal abrasions to optic nerve avulsion .
permanent loss of vision ensued in six cases and was due to traumatic optic neuropathy in each case one in association to zygomatico maxillary complex fracture , two with orbital fractures , and three with frontal fractures .
the type of facial fracture was found to be an important factor in relation to visual deterioration .
nine of thirty - six patients with zygomatico maxillary complex fractures were associated with visual impairment .
all patients with enophthalmos had sustained some form of orbital fracture , either a pure blow out fracture or a medial wall fracture .
figure 3 shows a patient with enophthalmos . where enophthalmos is accompanied by diplopia that is not resolving
a total of five patients ( 5/93 = 5.37% ) complained of diplopia in one or more directions of gaze three associated with orbital fractures , one with lefort iii level fracture , and one with zygomatic complex fracture .
follow up showed resolution of visual symptoms within 6 months of the injury with early surgical repair .
sixteen patients ( 16/93 = 17.2% ) were confirmed to have infraorbital nerve disorders on initial examination seven of them were associated with orbital fractures and the rest were associated with zygomatic complex fractures and other maxillary fractures . on subsequent follow up , it was noted that 13 patients had completely recovered from infraorbital paresthesia after successful surgical management .
one in association with orbital blow out fracture and other in relation to zygomatic maxillary complex fracture .
although alarming to the patient , the emphysema disappears in a few days and its only significance is that a communication has been established between the orbit or the periorbital tissues and potential source of infection , so that antibiotic cover is desirable .
a 34-year - old patient was diagnosed as retrobulbar haemorrhage based on the signs and symptoms shown in figure 4 .
retrobulbar hemorrhage is unpredictable and variable in its effects upon retinal circulation but will , if progressive and untreated , irreversible ischemia of the retinal cells and permanent blindness .
if the papillary response to stimulation by direct light becomes diminished and is accompanied by progressive dilatation and reduced visual acuity , immediate action is indicated . retrobulbar hemorrhage
fifty - five patients who sustained mandibular fractures were examined and 34.5% ( 19 of 55 ) sustained eye injuries .
four patients who sustained nasal fractures were examined and one ( 25% ) sustained eye injury .
seventy- one patients with mid - facial fractures were examined and 95.7% ( 68 of 71 ) had eye injuries54 were males and 14 were females .
six patients with frontal fractures were examined and 83.3% ( 5 of 6 ) had eye injuries three were males and two were females .
the type of ophthalmic injury with respect to the location of the fracture , the seriousness of the injury , and the extent of visual disability were analyzed .
table 2 illustrates the incidence of eye abnormalities , according to their severity in the population of study .
table 3 illustrates the same in relation to the type of mid - facial fracture sustained .
ninety - three of the patients ( 68.3% ) examined sustained eye injuries of various types .
of these , 61.2% were temporary or minor , 29.03% were moderate , and 9.6% were serious .
minor ophthalmic injuries like eyelid swelling / bruising may cause subcutaneous palpebral hemorrhages which gradually absorb .
twenty - seven patients ( 29.3% ) suffered moderately severe ophthalmologic injuries ( 33 in number ) , examples of which include minor eyelid and conjunctival lacerations and enophthalmos .
eyelid and conjunctival lacerations require suturing with careful apposition of the wound edges using a fine suture material .
all lens injuries should be referred to the ophthalmologist , there being no urgency for treatment of pure lenticular injuries .
nine patients ( 9.6% ) sustained severe eye injuries such as retinal or vitreous injury or optic nerve damage .
of those nine patients , six patients ( 66.6% ) lost vision in the affected eye .
left eye was affected in 49 patients ( 49/93 = 52.6% ) . when a tear of the retina is present , specialized ophthalmic treatment is usually needed .
similarly , detachment of retina is accompanied by a corresponding visual field defect and requires specialist attention .
all blunt ophthalmic injuries require fundus examination within a week of the injury to exclude retinal tear and/or detachment .
severe injuries such as proptosis give little damage to the eye itself , provided it is reduced early .
incidence of ophthalmic disorder in the population of study incidence of ophthalmic disorder in relation to midfacial trauma ophthalmic disorders in relation to other fractures subconjunctival hemorrhage two - third of all the patients with orbital fracture suffered a severe ophthalmic injury ( 7/11 = 63.6% ) .
three of eight patients with lefort ii level fracture had severe ophthalmic injury , whereas lefort i level fracture was not associated with any severe ophthalmic injury .
sixteen mandibular fractures were associated with mild ophthalmic injury , whereas three were associated with moderate complications .
ct scan image showing orbital # twenty - seven of 93 patients ( 29.09% ) had suffered transient or permanent visual loss .
causes of impaired vision varied from minor self - healing corneal abrasions to optic nerve avulsion .
permanent loss of vision ensued in six cases and was due to traumatic optic neuropathy in each case one in association to zygomatico maxillary complex fracture , two with orbital fractures , and three with frontal fractures .
the type of facial fracture was found to be an important factor in relation to visual deterioration .
nine of thirty - six patients with zygomatico maxillary complex fractures were associated with visual impairment .
all patients with enophthalmos had sustained some form of orbital fracture , either a pure blow out fracture or a medial wall fracture .
figure 3 shows a patient with enophthalmos . where enophthalmos is accompanied by diplopia that is not resolving
a total of five patients ( 5/93 = 5.37% ) complained of diplopia in one or more directions of gaze three associated with orbital fractures , one with lefort iii level fracture , and one with zygomatic complex fracture .
follow up showed resolution of visual symptoms within 6 months of the injury with early surgical repair .
sixteen patients ( 16/93 = 17.2% ) were confirmed to have infraorbital nerve disorders on initial examination seven of them were associated with orbital fractures and the rest were associated with zygomatic complex fractures and other maxillary fractures . on subsequent follow up ,
it was noted that 13 patients had completely recovered from infraorbital paresthesia after successful surgical management .
two male patients had orbital emphysema one in association with orbital blow out fracture and other in relation to zygomatic maxillary complex fracture .
although alarming to the patient , the emphysema disappears in a few days and its only significance is that a communication has been established between the orbit or the periorbital tissues and potential source of infection , so that antibiotic cover is desirable .
a 34-year - old patient was diagnosed as retrobulbar haemorrhage based on the signs and symptoms shown in figure 4 .
retrobulbar hemorrhage is unpredictable and variable in its effects upon retinal circulation but will , if progressive and untreated , irreversible ischemia of the retinal cells and permanent blindness .
if the papillary response to stimulation by direct light becomes diminished and is accompanied by progressive dilatation and reduced visual acuity , immediate action is indicated . retrobulbar hemorrhage
injuries to globe and adnexal structures occur frequently during blunt facial trauma . in the present study , 34.5% of the mandibular fractures , 25% of the nasal fractures ,
95.7% of the mid face fractures , and 83.3% of the frontal fractures were associated with ophthalmic injury of some severity .
( 1983 ) , after formal ophthalmologic examination of patients with blunt facial trauma , found the following incidence of eye injuries29% mandibular fractures , 59% nasal fractures , 76% mid - face fractures , and 89% frontal fractures .
al qurainy et al . ( 1991 ) found an overall incidence of 90.6% ophthalmic injury in 363 patients with mid - facial injury .
gordon r. miller and tenzel ( 1967 ) reported five patients of 30 with mid - facial fractures to have serious ophthalmic complications .
( 1983 ) reported 79% temporary injuries in 382 patients ( 680 in number ) , 18% moderate injuries in 90 patients ( 401 in number ) , and 3% blinding injuries in 22 patients .
1991 ) presented 230 patients ( 230/363 = 63.4% ) with temporary injuries , 57 patients ( 57/363 = 15.7% ) with moderate injuries , and 42 patients ( 42/363 = 11.6% ) with blinding injuries .
( 2000 ) showed a 9% incidence of severe injury in a retrospective evaluation 104 patients with maxillofacial trauma .
( 2009 ) reported that 66.6% had minor ocular injuries such as subconjunctival hemorrhage , iris sphincter tear , and corneal abrasion ; 10% had major injuries like ruptured globe and retinal hemorrhage .
the present study shows 57 patients with minor or temporary injuries ( 57/93 = 61.2% ) , which were totally 176 in number .
twenty - seven patients ( 27/93 = 9.6% ) suffered moderately severe injuries , which were totally 33 in number .
nine patients ( 9/93 = 9.6% ) sustained severe eye injuries , totally 24 in number .
our figure of 9.6% severe injuries is high as compared to 3% incidence shown by holt et al .
( 1983 ) found that 90 patients had moderately severe eye injuries . amongst them , 3% had mandibular fractures , 7% had nasal fractures , 70% mid - face fractures , and 20% frontal sinus and supra orbital fractures . in the present study of total patients with moderately severe injuries ,
11.2% were associated with mandibular fractures , 3.7% had frontal fractures , and 85.1% were found in mid - facial fractures .
kai lund ( 1971 ) reported diplopia in six patients of a total of 62 patients with fractures of zygoma .
( 1985 ) gave an incidence of 74.5% of diplopia in pure blow out fractures .
( 2009 ) reported an incidence of 16% symptomatic diplopia . in the present study ,
a total of five patients had signs and symptoms of diplopia three were associated with orbital fractures and two were associated with zygomatico maxillary complex fractures .
merrill j. reeh and tsujinmura ( 1966 ) evaluated 12 cases of blow out fractures of the orbit and recorded the ophthalmic complications of diplopia and enophthalmos .
( 1985 ) reported an almost similar incidence of enophthalmos as diplopia in blow out fractures of the orbit .
( 2000 ) reported 6% of patients to have enophthalmos of 4 - 6 mm . in the present study , 9.6% ( 9 of 93 ) had enophthalmos and most of them were males .
all the nine patients had orbital fractures , i.e. , 9 of 11 ( 81.8% ) had enophthalmos .
fractures of the mid - facial region , especially zygoma usually affect the infraorbital foramen , which is the weakest point of the malar complex and sensory disturbances of the infraorbital nerve are practically always present in the acute stage .
kai lund ( 1971 ) reported sensory disturbances in the infraorbital region in 41 patients of the 62 patients with fractures of the zygoma .
amin el - attar ( 1985 ) showed a 50% incidence of infraorbital nerve anesthesia in all zygomatico - orbital fractures .
peter jugell and lindqvist ( 1987 ) told 81% incidence of paresthesia of the infraorbital nerve in 68 patients with the fractures of zygomatic complex .
the present study shows 16 patients with infraorbital nerve disorders seven of them ( 63.6% ) had orbital fractures and nine ( 25% of all patients ) were in conjunction with zygomaticomaxillary complex fractures .
the present study shows a low incidence of infraorbital nerve disorders in comparison to the previous mentioned studies .
huang et al . ( 1977 ) reviewed 10 patients with retrobulbar hemorrhage in eight years .
the present study also reports a case of retrobulbar hemorrhage in a 34-year - old male patient with zygomaticomaxillary complex fracture .
transient or permanent visual loss has been reported in previous studies in relation to maxillofacial trauma .
1991 ) reported a 15.4% ( 56 of 393 ) decrease in visual acuity . in a retrospective analysis by ashar
et al.(1998 ) , of 49 patients admitted with mid - facial fractures , ten patients lost vision in one eye .
shantha amrith ( 2000 ) reported 23% patients with decrease in visual acuity , with 12.5% having permanent visual impairment .
the present study shows 29.09% ( 27 of 93 ) with transient or permanent visual loss .
the concomitant occurrence of globe rupture and blow out fracture of the orbit is a rare occurring situation .
( 1970 ) reported two cases of concomitant blow out fractures of the orbit and globe rupture .
paul m. cherry ( 1972 ) reported 34 patients with direct or indirect rupture of the globe .
( 2000 ) reported four cases of globe rupture three with complicated fractures and one with orbital fracture . in the present study , simultaneous occurrence of a blow out fracture and
the present study shows two cases of orbital emphysema in two young males one in relation to blow out fracture of the orbit and one in relation to zygomaticomaxillary complex fracture .
facial fractures have been reported to increase the risk of developing an ocular injury by a factor of 6.7 when compared with major trauma in patients with no facial fractures .
the very low incidence of ophthalmic injury in previous studies probably indicates that significant ophthalmic pathology may have gone undetected , or only the more serious ocular injuries were reported while mild and moderate injuries were neglected .
the overall incidence of ophthalmic injury of any severity in the present study is 68.3% with the highest incidence in relation to midfacial trauma , i.e. , 95.7% .
the results of this present study reinforce the contention that road traffic accidents cause more severe ocular injuries than any other cause of facial trauma .
two - third of all the patients with orbital fractures were associated with severe ocular disorder , followed by frontal fractures .
then came the zygomaticomaxillary complex fractures , whereas no severe ocular complication was reported in mandibular or nasal fractures . fortunately , many of the ocular injuries were transient and of no permanent consequence .
however , the incidence of 9.6% ( 9 of 93 ) with blinding and serious injuries is significant .
of particular importance are those of optic nerve injury ( 6.4% or 6 patients ) .
the results of eye examination while they do not often alter the type of fracture repair may influence the indications and timing of the repair because treatment of certain ophthalmic injuries , such as optic nerve compression , must be instituted at once .
it is suggested that all traumas to the face , particularly above the level of the mouth , require a careful eye examination , including an estimation of the visual acuity of each type .
the study indicates that all patients with reduced visual acuity and those with complex facial fractures are likely to have sustained ocular injury that warrants referral to an ophthalmologist
. the index of suspicion for ocular injury must also be high in patients with mid - facial fractures caused by road traffic accidents .
considerable care should be taken to ensure that all patients who may have sustained eye injuries in association with facial fractures are managed appropriately to prevent any blinding complications . at the same time
, it would be wise to educate the general public about the impact of maxillofacial trauma and how some accidents can be prevented .
Output:
| background : ophthalmic injuries commonly occur in patients with facial fractures . this study was set up to determine the incidence of ophthalmic injuries as assessed by an ophthalmologist , in patients who had sustained maxillofacial fractures.objective:to determine the incidence of ophthalmic injuries in maxillofacial fractures in indian population.materials and methods : a study of 136 patients who had sustained facial trauma sufficient to lead to a facial bone fracture was undertaken and the patients received a comprehensive examination by an ophthalmologist and an orthoptist within one week of injury .
all the patients sustaining confirmed maxillofacial fractures were examined by an ophthalmologist for any associated ocular injury .
the ophthalmic injuries were classified into three categories mild , moderate , severe.resultsninety-three patients ( 68.3% ) examined sustained eye injuries of various types .
of these , 61.2% were temporary or minor , 29.03% were moderate , and 9.6% were serious .
the highest incidence was found in association with mid face fractures , i.e. , 95.7% .
fifty - seven patients sustained 176 minor ophthalmologic injuries ; 27 patients suffered moderately ; 33 had severe ophthalmic injuries .
nine patients sustained severe eye injuries.conclusion:it is suggested that all traumas to the face , particularly above the level of the mouth , require a careful eye examination , including an estimation of visual acuity of each type . |
PubmedSumm118717 | ***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: egypt was blessed with the river nile and ancient culture but was deemed with liver diseases .
liver cirrhosis is a common disease in egypt as egypt has the highest incidence rate of hcv infection worldwide ( 1 ) .
up to 20 % of hospitalized patients with cirrhosis develop aki ( 2 ) and once aki occurs there is a reported fourfold increased risk of mortality ( 3 ) .
typically , patients with decompensated liver cirrhosis have significant circulatory dysfunction which is characterized by a vasodilatory state , lower total peripheral resistance , activated renin - angiotensin - aldosterone system ( raas ) and finally renal arterial vasoconstriction ( 4 ) . in cirrhosis ,
aki types include pre - renal azotemia , hepatorenal syndrome ( hrs ) and acute tubular necrosis ( atn ) with prevalence rates of 68% , 25% , and 33% respectively but their effect on mortality risk varies ( 2 ) .
unfortunately these forms of aki are difficult to distinguish clinically as serum creatinine ( scr ) , the clinical standard to define kidney function , poorly discriminates aki type in cirrhosis ( 5 ) .
furthermore , various factors can affect serum creatinine in cirrhotic patients such as age , gender , nutritional status , muscle mass , drug and volume distribution in addition deranged hepatic synthesis of the precursor ( creatine ) may contribute to impaired creatinine production in liver cirrhosis so utilization of serum creatinine concentration for diagnosing renal dysfunction could be even more unsatisfactory ( 4 ) .
recently , in an effort to improve the definition of aki and to highlight the importance of non - hrs kidney dysfunction in cirrhosis , the acute dialysis quality initiative ( adqi ) and the international ascites club ( iac ) jointly published a consensus statement regarding aki classification ( 6 ) , incorporating the risk , injury , failure , loss and end stage disease ( rifle ) and the acute kidney injury network ( akin ) guidelines .
iac definition of hrs ( 7 ) was classified as a specific form of aki ( 8) . management of aki in the setting of cirrhotic patients depends primarily on detection of the cause .
hrs is treat ed pharmacologically whereas pre - renal azotemia is treated with plasma volume expansion which is not suitable in management of atn ( 9 , 10 ) .
neutrophils gelatinase - associated lipocalin ( ngal ) is a novel biomarker for diagnosing acute kidney injury ( aki ) .
several studies have demonstrated the utility of early ngal measurements for predicting the severity and clinical outcomes of aki ( 11 , 12 , 13 , 14 ) .
in fact , urine il-18 has been shown to serve as an accurate biomarker to differentiate atn from other etiological factors of renal disease ( 15 ) . moreover ,
the prognostic role of urine il-18 has been validated in general patient groups admitted to icu ( 16 ) .
therefore , the study was to assess the ability of urinary ngal and il-18 as early biomarkers of aki in patients with cirrhosis .
this is a cross sectional study included 160 patients with cirrhosis admitted to the liver units in zagazig university hospitals from july 2012 to december 2012 with history of follow up in outpatients clinics .
exclusion criteria include : a ) patients with hepatocellular carcinoma or cholangiocarcinoma ; b ) liver transplant patients ; c ) chronic kidney diseases patients maintained on regular hemodialysis before admission ; and d ) kidney transplant patients .
study design was approved by institutional review board ( irb ) of faculty of medicine , zagazig university .
patients included in the study gave informed written consents in accordance with the declaration of helsinki .
clinical and biochemical data were collected at the time of admission to liver units in zagazig university hospitals with reference to previous patients data done in outpatient clinics .
child - pugh score and meld score were calculated on admission ( 17 , 18 ) . estimated gfr was calculated using mdrd equation ( 19 ) .
a fresh urine sample was taken to measure the urinary levels of sodium , creatinine , ngal and il-18 .
classification of patients patients were classified into three groups : a ) non ascetic patients ( n=42 ) ; b ) ascetic patients without renal impairment ( n=50 ) , and c ) ascetic patients with renal impairment ( n=68 ) .
this classification was used because it reflects the different stages of cirrhosis ( 20 ) .
patients with renal impairment was further divided into four subgroups : a ) pre - renal azotemia ; b ) chronic kidney disease ( ckd ) ( 21 ) ; c ) hrs ( 7 ) ; and d ) atn ( 22 ) .
the definitions for these different causes of renal impairment are shown in the supplementary material urine samples for ngal and il-18 levels were immediately centrifuged , separated and stored at -80 c until further analysis .
urinary ngal was measured using ngal elisa kit ( biovendor gmbh , germany ) in relation to urinary creatinine .
urinary il-18 was measured using a human il-18 enzyme - linked immunosorbent assay kit ( medical and biologic laboratory , nagoya , japan ) in relation to urinary creatinine .
routine biochemical parameters were measured by calorimetric methods ( spinreact , sa ctra , and santa coloma , spain ) . results for continuous variables were expressed as meansd .
comparisons among groups were made with analysis of variance for continuous normal - distributed variables and with chi - squared test for categorical variables .
characteristics of the patient population the demographic , clinical data and biochemical parameters of all patients are shown in table 1 .
patients with renal impairment were divided into the four subgroups as show in table 2 . demographic , clinical and laboratory data of all patients .
meld : model for end - stage liver disease , ngal : neutrophil gelatinase - associated lipocalin .
characteristics of renal impairment patients ckd : chronic kidney disease , hrs : hepatorenal syndrome , atn : acute tubular necrosis .
urinary neutrophil - gelatinase associated lipocalin ( ngal ) patients with renal impairment had higher urinary ngal levels ( 357.78228.51 g / g creatinine ) compared to those of patients without renal impairment , either with or without ascites ( 96.8435.58 , 113.7647.98 g / g creatinine respectively ) .
the mean value of urinary ngal in hrs ( 380.6 132.32 g / g creatinine ) was significantly higher compared to pre - renal azotemia patients ( 161.15 60.75 g / g creatinine , p = 0.0015 ) and significantly lower compared to atn patients ( 580.51 238.75 , p=0.0001 ) furthermore urinary ngal levels in patients with ckd ( 232.6341.31 g / g creatinine ) were significantly different from those of patients with hrs ( p = 0.003 ) ( figure 1 ) .
box - plot of urinary ngal levels according to the study subgroups of impairment of kidney function . in simple regression analysis ,
urinary ngal was positively correlated with serum creatinine ( r= 0.465 , p<0.001 ) , urinary il-18 ( r=0.9 , p<0.001 ) , fractional excretion of na ( fena ) ( r= 0.687 , p<0.001 ) and mean blood pressure ( r=0.339 , p=0.005 ) in patients subgroups with renal impairment ( table 3 ) .
: regression coefficient the cut - off value of urinary ngal that differentiate between patients with aki and those with other causes of renal impairment was 286.3 g / g creatinine ( area under roc curve is 0.909 ) with ( sensitivity 95.5 % , specificity 76.1 % ) with positive predictive value ( ppv ) of 65.6 and negative predictive value ( npv ) of 99.2 ( figure 3 ) .
urinary interleukin -18 ( il-18 ) patients with renal impairment had higher urinary il-18 levels ( 983594 g / g creatinine ) compared to those of patients without renal impairment , either with or without ascites ( 296.56113 , 254.577.9 g / g creatinine respectively ) .
we observed that patients with atn had the highest values of urinary il-18 , while patients with pre - renal azotemia had the lowest values ( 1687447 vs. 451.47121.73 g / g creatinine , respectively ; p=0.0001 ) .
patients with hrs had intermediate values ( 953273 g / g creatinine ) , which were significantly higher than those of patients with pre - renal azotemia ( p=0.0015 ) and lower than those of patients with atn ( p=0.0001 ) .
urinary il-18 levels in patients with ckd ( 58298.24 g / g creatinine ) were significantly different from those of patients with hrs ( p=0.001 ) ( figure 2 ) .
box - plot of urinary il-18 levels according to the study subgroups of impairment of kidney function . in simple regression analysis ,
urinary il-18 was positively correlated to serum creatinine ( r=0.422 , p<0.001 ) , fena ( r = 0.807 , p<0.001 ) and mean blood pressure ( r= 0.329 , p=.006 ) ) in patients subgroups with renal impairment ( table 3 ) .
the cut - off value of urinary il-18 that differentiate between patients with aki and those with other causes of renal impairment was 1119.6 g / g creatinine ( area under roc curve is 0.975 ) , with ( sensitivity 95.5 % , specificity 91.3 % ) with ppv of 84 and npv of 99.3 ( figure 3 ) .
receiver operating characteristic ( roc ) curves to evaluate the capability of urinary il-18 , urinary ngal and serum creatinine to diagnose acute tubular injury .
in fact , atn is an important precipitating factor for the development of hepatorenal syndrome ( hrs ) ( 2 , 18 ) .
it has been proposed that intense renal vasoconstriction in hrs , if prolonged , may lead to tubular ischemia and ultimately progress into atn ( 24 , 25 , 26 ) .
therefore , it may be difficult to distinguish hrs from atn in clinical settings . in general patients without liver cirrhosis ,
diamond et al . have shown that , in cirrhotic patients , fena may not correspond to the usual range for general patients with atn ( 27 ) .
therefore , fena is a less useful diagnostic tool for tubular injury in patients with advanced liver diseases , whose pre - existing hemodynamic states make them sodium - avid ( 2 , 18 , 27 , 28 ) .
our study demonstrated a significant difference of urinary ngal and il-18 in each category of aki : highest in atn , intermediate in hrs and low in pre - renal disease .
moreover , urinary ngal and il-18 levels in patients with pre - renal azotemia were similar to those with normal kidney function and stable ckd .
the mechanism by which patients with hrs have intermediate urinary ngal and il-18 levels remains unclear .
hrs physiology is thought to be an extreme pre - renal state ( 29 , 30 ) with severe renovascular vasoconstriction and decreased gfr , but normal intrinsic kidney function .
kidney function can return to normal after improvement of hepatic hemodynamics ( 29 , 30 , 31 ) , or after renal transplantation into a recipient with normal hepatic function ( 32 , 33 ) .
however , pathologic investigations have reported subtle kidney tubular and glomerular damage in hrs kidneys , some seen only with electron microscopy ( 24 , 34 ) , perhaps resulting from the cellular changes associated with chronic activation of angiotensin - aldosterone signaling ( 35 ) .
it is conceivable that profound renovascular constriction may cause sub - clinical tubular damage in at least a subset of nephrons , not detectable by urinary sodium , which is not sensitive enough to detect mild or patchy tubular epithelial damage .
our study also confirms previous studies demonstrating that a single urinary ngal or urinary il-18 measurement on hospital admission has the potential to assist in determining type of kidney dysfunction , perhaps improving patient management and outcomes ( 13 , 36 , 37 ) .
urinary ngal and urinary il-18 demonstrated an excellent discriminative power compared to serum creatinine ( auroc 0.909 for ngal , 0.975 for il-18 , 0.622 for cr ) for discriminating atn from hrs in our patients .
this is in contrast to traditional measurements of kidney and liver disease severity including scr and meld score .
our data demonstrate that patients with cirrhosis are at a high risk for acute renal impairment ( 33.1 % of the patients , 41 % of them diagnosed as atn and 26.4 % diagnosed as hrs ) .
the present findings seem to be consistent with previous studies ( 3 , 38 ) which confirm that non - hrs types of aki are common in patients with cirrhosis and further studies are needed to determine inciting factors of aki in this population .
first , scr inaccurately measures kidney function in cirrhosis ( 5 , 39 , 40 ) , and there is no widely available technique to accurately measure gfr in these patients .
second , absence of kidney biopsy , which is rarely performed in this population , because of the high risk of complications and consequently lack a correlation between renal pathology and urinary ngal and urinary il-18 .
urinary ngal and urinary il-18 have the ability to differentiate between aki types in patients with cirrhosis .
this could improve risk stratification for patients admitted to the hospital with cirrhosis , perhaps leading to early icu admission , transplant evaluation , prompt initiation of hrs therapy and early management of aki .
these findings , if confirmed in larger cohorts , could lead to the development of biomarker algorithms to rapidly identify patients with hrs and atn and accurately predict prognosis .
Output:
| abstractbackground and aim : acute kidney injury is a common complication in cirrhotic patients .
serum creatinine is a poor biomarker for detection of renal impairment in cirrhotic patients .
the aim of this study was to evaluate urinary neutrophils gelatinase - associated lipocalin ( ngal ) and urinary interleukin-18 ( il-18 ) as early biomarkers of acute kidney injury in cirrhotic patients.patients and methods:160 cirrhotic patients was enrolled in this study divided into 3 main groups according to presence or absence of ascites and renal impairment .
results : significant elevation of both urinary ngal and urinary il-18 in cirrhotic patients with renal impairment especially in patients with acute tubular necrosis ( atn ) was observed .
auroc was ( 0.909 ) with ( sensitivity 95.5 % , specificity 76.1 ) for urinary ngal and auroc was ( 0.975 ) , with ( sensitivity 95.5 % , specificity 91.3 % ) for urinary il-18.conclusion:both urinary ngal and urinary il-18 can act as urinary biomarkers of acute kidney injury in cirrhotic patient |
PubmedSumm118718 | ***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 unusual clinical presentation of cow 's milk allergy ( cma ) in an infant gave us the opportunity to observe a very fast and intriguing decrease of ige concentrations after allergen withdrawal , raising new questions about ige production and metabolism in newborns and infants .
a 17-day - old neonate , born to atopic parents at full term , was hospitalized in the children hospital of tours ( france ) for poor feeding and increasing diarrhoea for 4 days , associated with a severe metabolic acidosis , after a symptom - free interval of 2 weeks .
erythema and a pustular rash of the face as well as a gloves and socks- type skin rash were noted at 18 days of age , leading to the finding of very high concentrations of total ige ( 1298 kiu / l ) and ige specific to cow 's milk ( cm ) ( 83 kau / l , phadia ) ( figure 1 ) .
first - stage formula milk had been introduced on day 11 in addition to breastfeeding according to the mother , although it is possible that this had been given since birth .
although the clinical presentation was very unusual and severe [ 1 , 2 ] , the diagnosis of cma was confirmed by a rapid regression of all symptoms after withdrawal of cm proteins .
seven days later , total ige fell to 121 kiu / l and specific ige to 1.44 kau / l , and total ige returned to within the normal range ( 10.5 kiu / l ) ( figure 1 ) five days later .
the ige detected in the newborn had been self - produced since ige did not cross the placenta and his mother had no cm - specific ige ( not shown ) .
this ige immune response thus probably reflected a rapid maturation of ige+ b cells into plasmablasts , as recently evidenced in mice .
no less spectacular was the 100-fold decrease in ige concentrations 12 days later ( figure 1 ) , following exclusion of any cm lysate from the diet .
high levels of both specific and total ige are regularly observed in infant cow 's milk allergy and are reminiscent of experimental models where their coexistence reflects a genetic ( atopic ) background .
however , their parallel evolution , and the fact that they both appeared to be strictly antigen dependent , could also suggest that the ige measured in the total assay is mostly directed against cm .
pharmacokinetic modelling techniques were used to describe the elimination kinetics of total ige in this infant .
the kinetics model was ln ( c(t ) ) = ln ( cn ) ke t , where c(t ) is the ige concentration over time ( kiu / l ) , cn is the estimated ige concentration just after cm withdrawal , ke ( day ) is the first - order elimination constant , and t ( day ) is time . the ke parameter was estimated using log - linear regression .
the elimination half - life ( t1/2 ) was calculated as t1/2 = ln ( 2)/ke and was 1.7 days in this infant .
the combined kinetics of ige and omalizumab , an anti - ige humanized monoclonal antibody , were previously described in adults using pk - pd modelling .
the parameters describing the interindividual distribution of ige elimination kinetics in this study were used to estimate the confidence interval containing 90% of t1/2 values
although low , the t1/2 of ige of our infant was within this ci90t1/2 and thus has to be considered as
however , to calculate this elimination kinetics , it was postulated that ige production ceased after cm withdrawal , which is not necessarily the case .
it is therefore possible that the true ige t1/2 of this patient may be shorter than 1.7 days .
nevertheless , our findings suggest that the ige production stopped rapidly if not immediately after allergen elimination , suggesting that a very limited ige plasmablast life span combined with the very short ige half - life . whether this hypothetical ige plasmablast short life span is restricted to ige or whether it is due a more general immaturity of lymphoid niches in the newborn , as suggested in murine models , warrants further investigations in a cohort of cm allergic newborns .
Output:
| we report a case of a very fast and intriguing decrease in ige concentrations after exclusion from the diet of any cm lysate in an unusual clinical presentation of cow 's milk allergy in an infant .
analysis of ige kinetics after allergen elimination suggests rapid cessation of ige biosynthesis and a short ige half - life . |
PubmedSumm118719 | ***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 its introduction
to the market in 1991 , imidacloprid ( n-{1-[(6-chloro-3-pyridyl)methyl]-4,5-dihydroimidazol-2-yl}nitramide )
is the most successful neonicotinoid insecticide containing the 2-(n - nitroimidazolidin ) pharmacophore and the ( 6-chloropyrid-3-yl )
methyl residue .
imidacloprid has been
widely used on various types of grains , vegetables , fruits , and turfs
to control agricultural insect pests as well as on domesticated animals
to control ectoparasitic arthropods ( e.g. , k9 advantix ii and advantage ) . in 2009 ,
the market sales for imidacloprid in the united states
alone was estimated to be u.s .
this extensive use of imidacloprid in agriculture , including seed
dressing , in recent years might further add to its presence in soil and water as well as detection in various
kinds of fresh and processed fruits and vegetables .
these possibilities suggest that the potential for human
exposure to imidacloprid , in the general public as well as agricultural
workers , would be relatively high .
imidacloprid use was restricted
by the european commission in 2013 along with two other neonicotinoids
due to its potential risk for the collapse of bee populations .
the selective potency of imidacloprid to insects
versus mammals has been well characterized and attributed to the higher
affinity at the insect nicotinic acetylcholine receptors ( nachrs ) .
this selective action of imidacloprid and its systemic property
make imidacloprid a preferable choice of insecticide in various field
situations .
in addition , imidacloprid
is relatively more water - soluble when compared to other classes of
insecticides ( e.g. , organochlorine , organophosphorus , and pyrethroid
insecticides ) and penetrates human skin slowly .
imidacloprid is also
known to be quite persistent , with an approximately 39 day photolysis
half - life at the soil surface ( a range of 26.5229 days ) and
an aerobic half - life of 3 years .
moreover , it is known that a plant metabolite , desnitro - imidacloprid ,
has been determined to be more toxic to mammals than the parent compound .
epidemiological studies suggest a link between exposure to
persistent
organic pollutants , including insecticides , and the epidemic of obesity
and diabetes .
recently , one animal study reported that exposure to contaminated
salmon oil containing persistent organic pollutants along with a high
fat diet resulted in insulin resistance , represented by hyperinsulinemia ,
glucose intolerance , and hypertriglyceridemia , as well as hepatic
steatosis , compared to control fed high fat diet alone in rats .
another study reported that exposure to dichlorodiphenyldichloroethylene
( dde ) has a biphasic effect on fasting blood glucose in high fat diet
fed male mice .
previously , a single study
reported that 20 mg imidacloprid / kg body weight / day through oral gavage
decreased body weight accompanied by significant elevation of serum
glucose , glutamic oxaloacetic transaminase ( got ) , glutamic pyruvic
transaminase ( gpt ) , and blood urea nitrogen in rats , whereas 10 mg
imidacloprid / kg body weight / day did not show such toxic effects .
another study concluded that imidacloprid ( 5
and 10 mg / kg bw / day ) has immunosuppressive effects , which might result
from the direct cytotoxic effects of imidacloprid against t - cells .
moreover , there are recent reports that imidacloprid
may have adverse effects on development . along with these papers ,
our previously published studies reported
that several pesticides , including imidacloprid , promote adipogenesis
in 3t3-l1 adipocytes and induce insulin resistance in c2c12 myotubes .
it is not known , however , if imidacloprid exposure alone or in combination
with other factors of obesity and insulin resistance , such as high
fat diet , will exacerbate obesity and insulin resistance symptoms .
thus , the current study was conducted to determine if exposure to
imidacloprid aggravated high fat diet - induced metabolic disorders
characterized by adiposity , dyslipidemia , hyperglycemia , and insulin
resistance in male c57bl/6j mice .
three - week - old male c57bl/6j
mice were obtained from the jackson laboratory ( bar harbor , me , usa ) .
semipurified powdered diets ( td 94048 , 4% fat w / w , low fat diet ; and
td 07518 , 20% fat w / w , high fat diet ) were based on harlan laboratories
( madison , wi , usa ) diets .
food ingredients were obtained from bio - serv
( flemington , nj , usa ) .
glucose and total cholesterol assay kits were
purchased from genzyme diagnostics ( charlottetown , pe , canada ) .
mouse
leptin assay kit was purchased from r&d systems ( minneapolis ,
mn , usa ) .
serum insulin level was analyzed with
mouse insulin elisa kit from alpco ( salem , nh , usa ) .
the amounts of
triglyceride were quantified using infinity triglycerides reagent
from thermo scientific ( waltham , ma , usa ) , and other chemicals were
purchased from fisher scientific ( pittsburgh , pa , usa ) .
radioimmunoprecipitation
assay ( ripa ) buffer supplemented with 1% protease inhibitor was purchased
from boston bioproducts inc .
rabbit antibodies
to ampk , phosphorylated ampk ( pampk ) , acetyl - coa
carboxylase ( acc ) , phosphorylated acc ( pacc ) , and horseradish peroxidase - conjugated
goat anti - rabbit igg were purchased from cell signaling technology
( beverly , ma , usa ) .
rabbit antibodies to sirtuin 1 ( sirt1 ) , peroxisome
proliferator - activated receptor gamma coactivator 1-alpha ( pgc-1 ) ,
and -actin were purchased from santa cruz biotechnology ( dallas ,
tx , usa ) .
ca / calmodulin - dependent protein kinase kinase
( camkk ) rabbit antibody was purchased abcam inc .
human recombinant insulin ( novolin , 100 u / ml ) was purchased
from novo nordisk pharmaceuticals industries inc .
dextrose ( 50% ) and bacteriostatic 0.9% sodium chloride injection were
obtained from hospira , inc .
all animal work was conducted in compliance
with the institutional animal care and use committee at the university
of massachusetts under protocol no .
mice were housed in
a temperature- and humidity - controlled room with a 12 h light / dark
cycle .
diet and water were given to mice ad libitum
throughout the experiment and were provided fresh twice a week .
after a 2 week adaptation ,
the mice were fed a control diet ( 4% fat w / w ) and subjected to baseline
tests for insulin tolerance and glucose tolerance .
all animals were
then divided into two dietary groups ( low fat and high fat diets ) ;
each dietary treatment group contained four imidacloprid treatment
doses ( 0 , 0.06 , 0.6 , and 6 mg / kg bw / day ) .
doses of imidacloprid were determined on the basis of previous
publications ; the highest imidacloprid dose was based on a no - observed - adverse - effect - level
( noael ) of imidacloprid at 5.7 mg / kg bw / day , and the lowest dose of
imidacloprid was based on estimated average daily intake of imidacloprid
of 60 g / kg body weight / day .
imidacloprid contents
in low fat diets were 0 , 0.516 , 5.16 , and 51.6 mg imidacloprid / kg
diet .
imidacloprid contents in high fat diets were 0 , 0.744 , 7.44 ,
and 74.4 mg imidacloprid / kg diet .
the average consumptions of imidacloprid
at the end of the study were 0 , 0.07 , 0.7 , and 7 mg / kg bw / day in low
fat dietary groups and 0 , 0.08 , 0.8 , and 7 mg / kg bw / day in high fat
dietary groups .
imidacloprid intakes between low fat diet and high
fat diet were not statistically different . at the end of the study , mice were fasted for 4 h and sacrificed
by co2 asphyxiation .
blood was collected by cardiac puncture ,
and serum was separated by centrifugation at 2000 g for 20 min .
the organs ( kidney , heart , liver , spleen , pancreas ,
and adipose tissues including epididymal , mesenteric , retroperitoneal ,
and subcutaneous adipose tissues ) were weighed following sacrifice .
one - eighth of the epididymal adipose tissue was kept in 10% buffered
formalin and used for adipocyte size determination .
the other parts
of the epididymal adipose tissue and all other organs including gastrocnemius
were snap frozen with liquid nitrogen and stored at 80 c
until analysis .
the levels of total
cholesterol , leptin ,
nonesterified fatty acids ( nefa ) , triglyceride ( tg ) , and insulin in
serum were determined with commercial kits following the manufacturers
instructions .
itt
was performed during
adaptation and treatment at weeks 5 and 9 as previously described .
all mice were fasted for 4 h. blood glucose
from the tail vein was measured at 0 , 15 , 30 , 60 , and 120 min post - intraperitoneal
injection of insulin solution ( 0.75 u / kg body weight ) , with a blood
glucose meter , advocate redi - code ( advocate meters inc . ,
dorado , puerto rico ) .
the areas under the curve ( aucs ) were calculated
with sigma plot 11.0 ( systat software , inc .
gtt was performed during
adaptation and treatment at weeks 6 and 11 as described previously .
all mice were fasted for 6 h before the first
measurement of blood glucose from the tail vein , and blood glucose
was measured with a blood glucose meter ( 0 min ) .
then , a 20% glucose
solution ( 2 g glucose / kg of body weight ) was administered intraperitoneally ,
and blood glucose levels were further monitored at 15 , 30 , 60 , and
120 min .
blood insulin level was also measured at 0 , 30 , 60 , and 120
min with a mouse insulin elisa kit from alpco .
aucs were calculated
with sigma plot . the homeostasis model assessment - insulin resistance
( homa - ir ) score was calculated with a homa - ir calculator ( university
of oxford ) .
epididymal adipose tissue
was fixed in 10% phosphate - buffered formalin and processed for paraffin
sectioning .
tissue sections ( 4 m )
were cut and stained with hematoxylin and eosin ( he ) staining .
pictures
were taken with an olympus ck2 inverted microscope ( olympus , tokyo ,
japan ) ( 100 magnification ) and microscope eyepiece camera ( amscope ,
irvine , ca , usa ) .
the mean area of 50 cells from each sample was measured with imagej
software .
briefly , pictures of the calibration slide ( amscope ) were
taken under the same settings as the tissue sections and were used
to set the scale in imagej , and then the areas of the adipocytes were
measured with imagej .
mouse epididymal
adipose tissue ,
liver , and gastrocnemius muscle were homogenized in trizol reagent
to extract total rna under rnase - free conditions .
total rna was reverse - transcribed
with a high - capacity reverse transcription kit ( applied biosystems ,
carlsbad , ca , usa ) .
mrna expression levels of fatty acid translocase
( fat / cd36 ) , sterol regulatory element - binding protein 1c ( srebp1c ) ,
tumor necrosis factor ( tnf ) , phosphoenolpyruvate carboxykinase
( pepck ) , peroxisome proliferator - activated receptor alpha ( ppar ) ,
glucose transporter type 4 ( glut4 ) , pyruvate dehydrogenase kinase
4 ( pdk4 ) , carnitine palmitoyltransferase 1b ( cpt1b ) , and 18s rrna
( 18s rrna ) were analyzed .
real - time polymerase chain reaction ( pcr )
was completed using a stepone plus real - time pcr instrument ( applied
biosystems ) and taqman probe - based gene expression analysis ( applied
biosystems ) .
respective integrated sequences used were nm_001159555.1
( cd36 ) , nm_011480.3 ( srebp1c ) , nm_001278601.1 ( tnf ) , nm_028994.2
( pepck ) , nm_001113418.1 ( ppar ) , nm_009204.2 ( glut4 ) , nm_013743.2
( pdk4 ) , nm_009948.2 ( cpt1b ) , and nr_003278.3 ( 18s rrna ) .
protein quantities
were determined using the assay kit ( bio - rad co. , hercules , ca , usa ) .
detections
were performed on an image station 4000 mm ( carestream health , new
haven , ct , usa ) with a clarity western ecl substrate kit ( bio - rad
co. ) .
data were analyzed
by proc mixed
of the sas software ( version 9.3 , sas institute inc . ,
cary , nc , usa ) .
for the result on body weight ( figure 1a ) , two - way repeated measures analysis of variance
( anova ) and the slice option in the least square ( ls ) means statement
were used to determine the differences at each time point . for all
other results , two - way anova along with ls means statement
p values < 0.05 are reported
as statistically significant . if there were significant interactions
between diet and imidacloprid , letters are used in the figures to
present the differences between each group .
when there were no interactions
between diet and imidacloprid , brackets are used in the figures to
represent overall differences between imidacloprid treatments and
control groups .
effects of imidacloprid on body weight , body weight gain ,
and food
intake : ( a ) body weight monitored weekly ; ( b ) body weight gain for
12 weeks ; ( c ) total food intake .
mice were fed a low fat diet or high
fat diet supplemented with ( 0 , 0.06 , 0.6 , and 6 mg / kg bw / day ) imidacloprid
for 12 weeks .
numbers are the mean se ( n =
58 for panels a and b ; n = 34 for
panel c )
to understand the effect of imidacloprid
on dietary fat induced
changes , we chose c57bl/6j male mice fed either a low fat ( 4% ) or
a high fat ( 20% ) diet .
high fat diets ( 4070% of kcal )
are known to induce obesity in this strain .
there were overall effects of diet or imidacloprid on body weight
( figure 1a ) .
significant
three - way interaction ( imidacloprid diet time ) was also
observed .
in high fat diet fed mice , all imidacloprid groups showed
a significant increase in body weight compared to the control group
from week 7 onward and maintained the trend throughout the experiment
( p < 0.001 for all weeks from 7 to 12 ) ( figure 1a ) .
no differences
of body weight were found in the low fat diet fed mice among all groups
throughout the experiment ( figure 1a ) .
overall , both dietary fat and imidacloprid significantly
affected body weight gain , and there was a significant interaction
between dietary fat and imidacloprid ( figure 1b ) . in high fat diet fed mice , imidacloprid
treatment groups ( 0.06 , 0.6 , and 6 mg / kg bw / day ) had significantly
greater weight gain compared to the high fat control group ( p = 0.0057 , 0.0149 , and 0.0038 , respectively ) ( figure 1b ) .
food intake
as determined by calorie consumption is shown in figure 1c . both imidacloprid and dietary
fat significantly affected the calorie intake alone but without any
interaction between them ( figure 1c ) .
mice fed the high fat diet had greater calorie
intake compared to mice fed the low fat diet ( p =
0.0080 ) .
there were no significant differences of calorie intake between
the control and three imidacloprid treatment groups .
however , there
was a significant difference of calorie intake between the 0.06 and
6 mg / kg bw / day imidacloprid treatment groups ( p =
0.0223 ) ( figure 1c ) .
organ
weights ( liver , pancreas , heart , kidneys , and spleen ) as well
as adipose tissue weights ( epididymal , subcutaneous , mesenteric , retroperitoneal ,
and total adipose tissue ) measured as percent of body weights are
shown in table 2 .
there
was a significant diet effect , but there were no imidacloprid and
diet imidacloprid interaction effects on liver , heart , and
spleen weights .
both imidacloprid and diet significantly affected
the kidney weight with a significant interaction . in high fat diet
fed mice , imidacloprid treatment groups ( 0.06 and 6 mg / kg bw / day )
had reduced kidney weight compared to the control group ( p = 0.0297 and 0.0006 , respectively ) .
there were overall effects of
diet and imidacloprid on all adipose tissue weights with interaction
except for mesenteric adipose tissue , for which only a diet effect
was observed .
in high fat diet fed mice , animals treated with imidacloprid
( 0.6 and 6 mg / kg bw / day ) had significantly greater epididymal ( p = 0.0337 and 0.0002 , respectively ) and retroperitoneal
( p = 0.0078 and 0.0008 , respectively ) adipose tissue
weights compared to the control group .
mice were treated with three doses
of imidacloprid ( 0.06 , 0.6 , and 6 mg / kg bw / day ) .
. means with different
letters within the same row are significantly different at p < 0.05 . abbreviations : ns , not significant .
histological analysis revealed that
there were significant effects
of diet and imidacloprid with diet imidacloprid interaction
on epididymal adipocyte size ( figure 2 ) .
imidacloprid ( 0.06 , 0.6 , and 6 mg / kg bw / day ) treatment
significantly increased adipocyte size in high fat diet fed mice ( p = 0.0081 , 0.0002 , and 0.0001 , respectively ) , but not in
low fat diet fed mice ( figure 2a , b ) .
effects of imidacloprid on adipocyte size : ( a ) representative
pictures
of epididymal adipose tissues after h&e staining ( 100 magnification ) ;
( b ) adipocyte size .
mice were fed a low fat diet or high fat diet
supplemented with ( 0 , 0.06 , 0.6 , and 6 mg / kg bw / day ) imidacloprid
for 12 weeks .
the serum
levels of glucose , cholesterol , leptin , nefa , tg , and insulin are
shown in table 3 . there
were overall treatment effects from both diet and imidacloprid ( without
interaction ) on blood glucose and insulin levels .
mice fed imidacloprid
( 0.06 and 6 mg / kg bw / day ) had significantly higher levels of blood
glucose compared to control groups ( p = 0.0096 and
0.0144 , respectively ) .
mice fed imidacloprid ( 6 mg / kg bw / day ) also
had significantly higher blood insulin levels compared to control
groups ( p = 0.0325 ) . there were overall treatment
effects from both diet and imidacloprid with their interaction on
leptin level .
compared to the high fat control group , animals fed
the high fat diet with ( 0.06 , 0.6 , and 6 mg / kg bw / day ) imidacloprid
had higher blood leptin levels ( p < 0.0001 , 0.0011 ,
and < 0.0001 , respectively ) .
there were overall treatment effects
from imidacloprid , but not diet and their interaction , on serum tg
levels .
mice fed imidacloprid ( 6 mg / kg bw / day ) had significantly higher
serum tg level compared to control groups ( p = 0.0099 ) .
there were significant effects of diet , but not to imidacloprid or
to their interaction , on cholesterol levels .
there were no significant
effects of both diet and imidacloprid on serum nefa levels .
mice were treated with three doses
of imidacloprid ( 0.06 , 0.6 , and 6 mg / kg bw / day ) .
. means with different
letters within the same row are significantly different at p < 0.05 .
abbreviations : ns , not significant ; tg , triglyceride ;
nefa , nonesterified fatty acid . to determine
the effect of imidacloprid and diet on glucose homeostasis , we measured
serum glucose levels during itt and gtt and measured serum insulin
level during gtt , which are presented in figure 3 and figure 1s . before treatment
, there were no differences between any of the
groups for itt , gtt , and insulin level ( figure 3a , d , g ) .
effects of imidacloprid on insulin tolerance
test ( itt ) ( a , b ,
c ) , glucose tolerance test ( gtt ) ( d , e , f ) , and insulin level determination
with serum from gtt ( g , h , i ) as the area under the curve ( auc ) .
mice
were fed a low fat diet or high fat diet supplemented with ( 0 , 0.06 ,
0.6 , and 6 mg / kg bw / day ) imidacloprid for 12 weeks .
blood was collected from the
tail vein , and glucose levels were determined at 0 min ; then the insulin
( itt ) or glucose solution ( gtt ) was administered by intraperitoneal
injection , and the glucose level was further measured at 15 , 30 , 60 ,
and 120 min . during gtt ,
the blood was collected from the tail vein
at 0 , 30 , 60 , and 120 min for determination of insulin level .
means
with different letters are significantly different at p < 0.05 . as shown in figure 3b , there were significant
diet and imidacloprid effects without interaction
on insulin tolerance after 5 weeks of treatment .
in particular , mice
that received the highest dose of imidacloprid ( 6 mg / kg bw / day ) had
significantly higher auc compared to control groups ( p = 0.0018 ) in week 5 ( figure 3b ) . after 9 weeks of treatment , there were significant effects
of diet and imidacloprid with interaction ( figure 3c ) .
high fat diet imidacloprid treated mice
at 6 mg / kg bw / day had significantly elevated auc compared to the high
fat control ( p = 0.0006 ) ( figure 3c ) .
as shown in figure 3e , only diet was
found to have a significant effect on impaired glucose tolerance at
week 6 . at week 11 ,
both diet and imidacloprid effects were observed
without interaction ( figure 3f ) . at the highest dose of imidacloprid ( 6 mg / kg bw / day ) ,
treated mice showed more severe glucose intolerance compared to control
groups ( p = 0.0331 ) ( figure 3f ) .
the serum samples collected from
the gtt tests were further utilized
for insulin level measurements .
there were significant diet and imidacloprid
effects with interaction on serum insulin level at both weeks 6 and
11 ( figure 3h , i ) .
high
fat diet with imidacloprid treated animals at 0.6 and 6 mg / kg bw / day
had significantly higher auc of insulin levels compared to high fat
controls ( p < 0.0001 for both 0.6 and 6 mg / kg
bw / day
at week 6 , p = 0.0007 and 0.0211 at week 11 , respectively )
( figure 3h , i ) .
similarly ,
there were significant diet and imidacloprid effects on homa - ir scores
with significant interaction at weeks 6 , 11 , and 12 ( figure 4 ) .
high fat diet with imidacloprid
( 0.6 and 6 mg / kg bw / day ) treated mice had higher homa - ir scores compared
with the high fat control ( figure 4 ) .
mice were fed
a low fat
diet or high fat diet supplemented with ( 0 , 0.06 , 0.6 , and 6 mg / kg
bw / day ) imidacloprid for 12 weeks .
homa - ir score was calculated during
the adaptation period , weeks 6 , 11 , and 12 , with a homa - ir calculator .
. means with different letters are significantly different
at p < 0.05 . because imidacloprid and high fat diet significantly affected the
lipid and glucose metabolism in mice , we first investigated their
effects on mrna expression levels of genes regulating lipid metabolism
in white adipose tissue .
cd36 , one of the fatty acid transporter proteins
in adipocytes , facilitates the cellular entry of lipoprotein derived
fatty acids , thus promoting the storage of triglycerides in adipose
tissue .
there were significant diet and
imidacloprid effects without interaction on cd36 mrna expression ( figure 5a ) .
compared to control
groups , mice fed with imidacloprid ( 6 mg / kg bw / day ) had significantly
higher expression of cd36 ( p = 0.011 ) ( figure 5a ) .
effects of imidacloprid
on molecular target genes involved in lipid
metabolism and inflammation in white adipose tissue : ( a ) fat / cd36 ,
fatty acid translocase ; ( b ) srebp1c , sterol regulatory element binding
protein 1c ; ( c ) tnf , tumor necrosis factor ; ( d ) representative
pictures ; ( e ) camkk , ca / calmodulin - dependent protein
kinase kinase ; ( f ) pampk/ampk , phosphorylated
amp - activated protein kinase-/amp - activated protein kinase- ;
( g ) pacc / acc , phosphorylated acetyl - coa carboxylase / acetyl - coa carboxylase .
mice were fed a low fat diet or high fat diet supplemented with ( 0 ,
0.06 , 0.6 , and 6 mg / kg bw / day ) imidacloprid for 12 weeks .
srebp1c is highly expressed
in adipose tissue and is a well - known
master regulator of the lipogenic pathway .
there was significant imidacloprid effect , without diet effects
or interaction , on srebp1c mrna expression in the white adipose tissue
( figure 5b ) .
mice fed
6 mg / kg bw / day imidacloprid had a significant increase in srebp1 expression
compared to controls ( p = 0.0035 ) ( figure 5b ) .
tnf , a pro - inflammatory cytokine , is highly expressed in
the adipose tissue of obese mice .
there were significant effects of diet and imidacloprid
as well as their interaction on tnf expression ( figure 5c ) .
mice fed a high fat diet
and imidacloprid at 6 mg / kg bw / day had an increased tnf mrna
expression level compared to high fat control ( p =
0.0029 ) ( figure 5c ) .
ampk is known as a master regulator of energy metabolism , and activation
of ampk leads to the stimulation of fatty acid oxidation and inhibition
of lipogenesis .
previously we reported
that imidacloprid may potentiate adipogenesis via an ampk mediated
mechanism in 3t3-l1 adipocytes . to determine
if oral administration of imidacloprid exerts its effect via a similar
mechanism , we have detected ampk and its downstream target ( acetyl
co - a carboxylase , acc ) as well as one of its upstream regulators ,
camkk , from epididymal adipose tissue
( figure 5d g ) .
there were significant imidacloprid and imidacloprid diet interaction
effects without diet effect on the expression of camkk ( figure 5e ) .
high fat diet
with imidacloprid ( 6 mg / kg bw / day ) had significantly reduced expression
of camkk compared to controls ( p = 0.0002 )
( figure 5e ) .
there
were significant diet and imidacloprid effects with interaction on
the ratio of expressions of pampk/ampk ( figure 5f ) .
high fat diet and imidacloprid
( 6 mg / kg bw / day ) fed mice had a significant decrease in the ratio
of pampk/ampk compared to high fat control ( p = 0.0028 ) ( figure 5f ) .
there was only an imidacloprid effect , without diet effect ,
on the ratio of phosphorylated acc / acc ( pacc / acc ) ( figure 5 g ) .
mice treated with imidacloprid
at 0.06 and 6 mg / kg bw / day had significantly lower pacc / acc ratios
compared to controls ( p = 0.015 and 0.0403 , respectively )
( figure 5 g ) .
these
results suggest that oral administration of imidacloprid might promote
adipogenesis via a camkk-ampk-dependent pathway in white
adipose tissue of mice .
liver is an important organ in regulating glucose and fatty acid
metabolisms ; thus , we further investigated the effects of imidacloprid
and high fat diet on two genes , pepck and ppar , which are the
rate - limiting enzyme for gluconeogenesis and a key regulator of fatty acid oxidation in liver , respectively .
there were significant diet and imidacloprid
effects with their interaction on the expression of pepck ( figure 6a ) . in mice
fed the
high fat diet , imidacloprid ( 0.06 and 6 mg / kg bw / day ) treatment groups
showed significantly higher mrna expression of pepck , compared to
control ( p = 0.0166 and 0.0336 ) ( figure 6a ) .
there were significant
diet and imidacloprid effects without interaction on ppar mrna
expression ( figure 6b ) .
mice fed imidacloprid at 0.6 and 6 mg / kg bw / day had significantly
reduced mrna expression of ppar compared to controls ( p = 0.0159 and 0.023 , respectively ) ( figure 6b ) .
effects of imidacloprid on molecular target
genes regulating lipid
and glucose metabolism as well as the ampk pathway in liver :
( a ) pepck , phosphoenolpyruvate carboxykinase ; ( b ) ppar , peroxisome
proliferator - activated receptor- ; ( c ) representative pictures ;
( d ) camkk , ca / calmodulin - dependent protein kinase
kinase ; ( e ) pampk/ampk , phosphorylated amp - activated
protein kinase-/amp - activated protein kinase- ; ( f ) pacc / acc ,
phosphorylated acetyl - coa carboxylase / acetyl - coa carboxylase ; ( g )
sirt1 , sirtuin 1 ; ( h ) pgc-1 , peroxisome proliferator - activated
receptor- coactivator-1. mice were fed a low fat diet
or high fat diet supplemented with ( 0 , 0.06 , 0.6 , and 6 mg / kg bw / day )
imidacloprid for 12 weeks .
we further investigated the effect of imidacloprid on protein
markers
important for lipid and glucose homeostasis in the liver .
pgc-1
is highly expressed in the liver and is known as a master regulator
of fatty acid oxidation .
two metabolic sensors ,
ampk and sirt1 , have been reported to directly increase pgc-1
activity .
there
were significant effects of imidacloprid and imidacloprid diet
interaction without significant effect of diet on camkk expression
( figure 6d ) .
high fat
diet with 6 mg / kg bw / day imidacloprid fed mice had a decrease in expression
of camkk compared to high fat control ( p =
0.0049 ) ( figure 6d ) .
significant effects of diet and imidacloprid with their interaction
were observed for the pampk/ampk and pacc / acc ratios
( figure 6e , f ) .
high
fat imidacloprid ( 6 mg / kg bw / day ) fed mice exhibited decreased ratios
of pampk/ampk and pacc / acc compared to high fat control
( p < 0.0001 and 0.0475 , respectively ) ( figure 6e , f ) . there were
effects of both diet and imidacloprid on sirt1 and pgc-1 expression
without interaction ( figure 6g , h ) .
mice treated with imidacloprid ( 0.6 and 6 mg / kg bw / day )
had a significant decrease in expression of sirt1 ( p = 0.0026 and 0.0121 ) and pgc-1 compared to controls ( p = 0.0356 and 0.011 , respectively ) ( figure 6g , h ) .
these results suggest that imidacloprid
might contribute to decreased fatty acid oxidation in the liver .
muscle is
responsible for 7090% of glucose disposal in our body , and insulin resistance in skeletal muscle is
the primary defect in type 2 diabetes . in muscle , glut4 is the main glucose transporter responsible for
glucose uptake in response to insulin stimulation .
it has been reported that mice lacking or overexpressing
glut4 have a decrease or increase in whole - body insulin sensitivity ,
respectively . in the current study , there
were significant effects of diet and imidacloprid without interaction
on muscle glut4 mrna expression ( figure 7a ) .
mice fed imidacloprid at 0.06 and 6 mg / kg
bw / day had significantly lower mrna expression of glut4 compared to
controls ( p = 0.0003 and 0.0012 , respectively ) ( figure 7a ) .
effects of imidacloprid
on markers regulating lipid and glucose
metabolism in gastrocnemius muscle : ( a ) glut4 , glucose transporter
type 4 ; ( b ) pdk4 , pyruvate dehydrogenase kinase 4 ; ( c ) cpt1 , carnitine
palmitoyltransferase 1 .
mice were fed a low fat diet or high fat diet
supplemented with ( 0 , 0.06 , 0.6 , and 6 mg / kg bw / day ) imidacloprid
for 12 weeks .
pdk4 , a kinase enzyme highly expressed in skeletal muscle ,
inactivates
the enzyme pyruvate dehydrogenase . as
a result ,
the pyruvate formed from glycolysis can not be oxidized ,
which leads to hyperglycemia due to the decrease in blood glucose
oxidation .
a previous study also reported
that pdk4 is overexpressed in skeletal muscle of people with type
2 diabetes , resulting in impaired glucose disposal . in the current mouse study , there were effects of diet
and imidacloprid on pdk4 mrna expression without interaction ( figure 7b ) .
mice fed imidacloprid
at 6 mg / kg bw / day had a higher expression level of pdk4 compared to
controls ( p = 0.0015 ) ( figure 7b ) .
cpt1 is a mitochondrial transmembrane
enzyme , recognized as rate
limiting for mitochondrial fatty acid -oxidation . in the current study
, there was a significant
diet effect on cpt1 mrna expression without imidacloprid effect and
interaction .
taken together , these results suggested that imidacloprid
and high fat diet might affect the expression of genes important for
lipid and glucose metabolism and contribute to adiposity and insulin
resistance in the current study .
in
this study , we demonstrated that dietary exposure to relatively
low doses of imidacloprid ( at or lower than noael ) exacerbated high
fat diet induced weight gain and insulin resistance in c57bl/6j male
mice during a 12 week treatment .
as such , it is the first mouse study
demonstrating the role of imidacloprid on the development of high
fat diet induced obesity and type 2 diabetes .
the current results
also suggest that imidacloprid may elicit its effects by post - translational
regulation of ampk via camkk and/or sirt1 in adipocytes and
the liver .
this finding is consistent with our previous reports that
imidacloprid inhibits the phosphorylation of ampk in 3t3-l1
adipocytes .
several studies have
reported an interaction between organophosphorous
insecticides ( diazinon and parathion ) and high fat diet , including
their contribution to increased weight gain and insulin resistance .
reported that persistent
organic pollutants ( pops ) in crude fish oil exacerbated high fat diet
induced increased visceral adipose tissue and insulin resistance compared
to refined salmon oil ( without pops ) in male sprague dawley
rats . in the ruzzin study , pops with high fat diet were reported to
induce increased liver srebp1c expression .
similarly , imidacloprid
exposure increased the expression of srebp1c in adipose tissue in
the current study .
in addition , our current results showed that imidacloprid
with high fat diet increased tnf ( a pro - inflammatory cytokine )
in adipose tissue of high fat diet fed mice , which may have significance
in insulin resistance .
a previous mouse study reported that
exposure to dde initially
facilitated high fat diet induced hyperglycemia at weeks 4 and 8 ,
which returned to normal at 1213 weeks .
reported
that pops with high fat diet increased homa - ir score and reduced insulin - stimulated
glucose uptake in skeletal muscle and adipose tissue .
this study is
consistent with the current results that imidacloprid with high fat
diet increased the blood glucose and insulin levels along with impaired
insulin resistance .
moreover , we observed that animals fed imidacloprid
with high fat diet potentiated gluconeogenesis in the liver by targeting
pepck and reduced glucose disposal from the skeletal muscle by decreasing
glut4 expression and glucose oxidation , both of which may have contributed
to overall impairment of glucose homeostasis .
it is important to point
out , however , that our results are limited because we did not measure
insulin - stimulated glut4 translocation in skeletal muscle .
nevertheless ,
it was previously reported that imidacloprid exposure might induce
insulin resistance by reducing insulin - stimulated glucose uptake and
phosphorylation of protein kinase b ( akt ) in adipocytes , hepatocytes ,
and myotubes .
thus , it is likely that
imidacloprid exacerbated high fat diet induced insulin resistance
by targeting the insulin signaling pathway . alternatively
inflammation , including the significance of pro - inflammatory cytokine
tnf , and oxidative stress were reported to be correlated with
the development of obesity and insulin resistance .
inflammation and oxidative stress are known to activate
jnk ( c - jun n - terminal kinase ) , which is linked to
insulin resistance .
thus , further studies
of imidacloprid s role in oxidative stress and inflammation ,
including the role of tnf and their contributions to obesity
and insulin resistance , are needed to understand how imidacloprid
elicits altered metabolism .
mice fed the high fat diet showed
physiological and metabolic changes
compared to low fat diet fed mice as expected ; including increased body weight ,
calorie intake , serum insulin level , homa - ir score , expression of
epididymal adipose tissue cd36 , tnf , adipocyte size , and impaired
insulin tolerance as well as glucose tolerance .
however , several studies
reported inconsistent results of lipogenesis in mice consuming a high
fat diet : increased , no change or decreased lipogenesis after high fat diet
feeding .
our current results show no significant
different expression levels of srebp1 , a key lipogenic gene , in adipose
tissue between high fat diet and low fat diet fed mice .
imidacloprid
is the most widely used neonicotinoid insecticide , and compared to highly lipophilic organochlorine
and organophosphorus insecticides , imidacloprid is relatively water - soluble .
imidacloprid is considered to be moderately
toxic , with an oral ld50 in rats of 420 mg / kg body weight ,
and the typical symptoms of poisoning include fatigue , cramps , and
muscle weakness . however , the dose we
used in the current study was based on a noael of 5.7 mg imidacloprid / kg
body weight / day or lower ; thus , we did not expect any of those acute
toxic symptoms in these animals .
a previous
mouse study showed that oral gavage of > 5 mg / kg bw / day imidacloprid
for 28 days resulted in immunosuppressive effects ; however , no changes
in body weight were observed for all doses of imidacloprid treatment
in that study .
another study reported
that oral administration of 20 mg / kg bw / day imidacloprid decreased
the body weight in rats ; however , this was not observed in 10 mg / kg
bw / day imidacloprid treated rats .
thus ,
the significance of the current study is the interaction between high
fat diet and imidacloprid , which would have significance for understanding
potential health implications of imidacloprid .
it is known that
imidacloprid is quickly absorbed from the gastrointestinal
tract and distributed in almost all organs and tissues .
although imidacloprid
intake between low fat diet and high fat diet in the current study
were not statistically different , we can not exclude the possibility
that high fat and low fat diet might have different effects on the
bioavailability of imidacloprid , thus leading to the differences observed
in the current study .
once absorbed , imidacloprid is degraded into
a variety of metabolites : 6-chloronicotinic acid , imidazolidine 4-
and 5-hydroxy compounds , olefinic imidacloprid , desnitro - imidacloprid ,
and the nitrosoimine compound .
these
metabolites are known to be excreted mainly in the urine as glutathione
and glycine conjugates of mercaptonicotinic acid and hippuric acid .
imidacloprid also photodegrades rapidly in water ,
with a half - life of <3 h. however , imidacloprid has been found
to be persistent in the environment with a photolysis half - life of
39 days at the soil surface ( a range of 26.5229 days ) when
absorbed by the soil . despite intensive
investigations and establishment of preventive
and therapeutic strategies for obesity and type 2 diabetes , these
diseases have increased significantly in the past few decades .
sedentary lifestyle and excessive caloric intake can only partially
explain the dramatic increase of metabolic diseases worldwide .
recently ,
air pollution and environmental contaminants such as bisphenol a ,
as well as other pops , have been suggested to contribute to the development
of obesity and insulin resistance . along with the current results , these reports provide compelling
evidence that environmental contaminants may contribute to the epidemic
of obesity , insulin resistance , and eventually type 2 diabetes . to conclude , our present finding is the first report that imidacloprid
exposure aggravates high fat diet induced obesity and insulin resistance
in c57bl/6j male mice .
the current results are significant in substantiating
a potential link between insecticide exposure , particularly imidacloprid ,
and dietary fat and adiposity as well as insulin resistance .
however ,
the underlying mechanisms by which imidacloprid promotes high fat
diet induced obesity and insulin resistance still need to be further
explored .
Output:
| imidacloprid ,
a neonicotinoid insecticide widely used in agriculture
worldwide , has been reported to promote adipogenesis and cause insulin
resistance in vitro .
the purpose of the current study was to determine
the effects of imidacloprid and its interaction with dietary fat in
the development of adiposity and insulin resistance using male c57bl/6j
mice .
imidacloprid ( 0.06 , 0.6 , or 6 mg / kg bw / day ) was mixed in a low - fat
( 4% w / w ) or high - fat ( 20% w / w ) diet and given to mice ad libitum for
12 weeks .
imidacloprid significantly promoted high fat diet - induced
body weight gain and adiposity .
in addition , imidacloprid treatment
with the high fat diet resulted in impaired glucose metabolism . consistently ,
there were significant effects of imidacloprid on genes regulating
lipid and glucose metabolisms , including the amp - activated protein
kinase- ( ampk ) pathway in white adipose tissue and liver .
these results suggest that imidacloprid may potentiate high fat diet - induced
adiposity and insulin resistance in male c57bl/6j mice . |
PubmedSumm118720 | ***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: among the chromosomal aberration syndromes , 1q duplications and 18q deletions have been reported separately .
the phenotype of 18q - syndrome is variable depending on the deleted region and size .
typical forms of 18q - syndrome include developmental delay , microcephaly , facial dysmorphism , growth retardation , congenital aural atresia , hypotonia , and limb anomalies12 ) . in patients with distal 18q22.3 - 23 deletions , dysmyelination and poor differentiation of grey and white matter on brain magnetic resonance image ( mri )
myelin basic protein ( mbp ) defect , contained in this region is considered responsible for brain dysmyelination .
galanin receptor ( galr1 ) gene is also located on 18q23 , which may be responsible for growth retardation of 18q - syndromes2 ) .
clinical features include plagiocephaly , large fontanelles , prominent forehead , down slanting palpebral fissures , low set ears , and others4 ) .
recent advanced genome wide screening with micro array - based cytogenetic technologies enabled us to detect the genomic imbalances with only a few hundred base pairs .
although interpretations of significance are not always possible , microarray - based comparative genomic hybridization ( acgh ) increases the identification of micro duplications or deletions in patients with previously unknown causes of congenital abnormalities and developmental delay5 ) .
we report on a 22-month - old boy presenting developmental delay and other abnormalities who was subsequently diagnosed with a new translocation karyotype of46,xy , der(18)t(1;18)(q32.1 ; q21.3)/46,xy ( 7.3% mosaicism ) by acgh , which had not been recognized by routine chromosomal analysis . to our knowledge
the 22-month - old patient was referred to our pediatric neurology department for developmental delay .
he was born at 40 weeks of gestation by repeated caesarean with no complications and a birth weight of 2,880 g ( 10th25th percentile ) .
he was a second child from a 36-year - old korean father with mild hearing impairment and 27-year - old filipino mother in good health .
old , he was sent to a pediatric cardiologist for heart murmur and diagnosed with a large patent ductus arteriosus ( pda ) , tricuspid regurgitation ( tr ) ( grade iv ) and mitral regurgitation ( grade ii ) by echocardiography .
a follow - up echocardiogram at 14 months showed disappearance of the pda and minimal tr .
he had experienced repeated respiratory infection and otitis media , and was once admitted for bronchitis at 14 months old . at 22 months old , patient 's height was 74 cm ( <3 percentile ) , weight 9.6 kg ( <3 percentile ) and head circumference 45.1 cm ( <3 percentile ) . on physical examination , he exhibited a mild dysmorphism of the face with frontal bossing , slight narrowing face , down slanting palpebral fissures , low lying ears , mild hypertelorism and a flat nose ( fig .
the patient began standing with assistance at 14 months old but could not stand or walk alone .
he spoke his first word at 12 months but could only say 3 meaningful words um - ma ( mama ) , a - bba ( papa ) , a - ppa ( painful ) .
he showed generalized developmental delay in standardized korean infant and child development tests at 22 months old .
total developmental quotient ( dq ) was 61.7 , and total developmental age ( da ) corresponded to 14.3 months old : the dqs ( corresponding das ) of gross motor / fine motor / personal social / language / cognitive adaptive areas were 47.8 ( 11 months)/60.8 ( 14 months)/78.2 ( 18 months)/52.1 ( 12 months)/69.5 ( 16 months ) .
laboratory findings at 22 months old were white blood cell 11,000/mm , haemoglobin 12.2 g / dl , and platelet 333/mm .
blood gases , electrolytes , blood ammonia , lactate / pyruvate , ketone , glucose , thyroid function tests , and serum iga level were within normal range .
, he was diagnosed with hearing impairment ( right , 70 db ; left , 50 db ) . at 39 months
old , he had been able to walk unassisted since 29 months ; however , he could say only 34 meaningful words .
his development was assessed as being increasingly more delayed : total dq 53.7 , total da 18.8 month .
serum insulin - like growth factor-1 was under 25.0 ng / ml ( reference , 54178 ng / ml ) , and human growth hormone ( gh ) was 1.3 ng / ml ( reference , < 0.76 ng / ml ) . at that time , his parents agreed to conduct genetic analysis .
the patient 's first chromosomal analysis was done by gtl - banding with a banding resolution of 550 ( 20 cells ) .
the second analysis was performed after acgh analysis and was done by gtg - banding with a banding resolution of 550 ( 164 cells ) ( neodin medical institute , seoul , korea ) .
oligonucleotide - based microarray analysis was performed using a 135k cgx-3 whole - genome microarray ( roche nimblegen , madison , wi , usa ) .
genomic dna was extracted from peripheral blood , and the patient 's dna and normal control dna ( human genomic dna : male / female , promega , madison , wi , usa ) were labeled with cy3 and cy5 with a roche nimlegen dna labeling kit .
array hybridization , washing and scanning were performed as specified by the manufacturer ( roche nimblegen ) .
fluorescence in situ hybridization ( fish ) analysis of 150 metaphase and 50 interphase fish analysis were done using bacterial artificial chromosome , clone , rp11 - 370k11(1q44 ) , and rp11 - 849i 19 ( 18q23),which located regions of gain or loss .
however , abnormal signals in the brain mri and the patient 's dysmorphic face suggested chromosomal aberration syndrome .
subsequent acgh analysis revealed a subtle copy - number gain of 2,255 oligo probes spanning ~46.38 mb at 1q32.1 1q44 ( chr1:200,797,519247,174,728 ) and a subtle copy - number loss of 874 oligo probes spanning ~46.38 mb at 18q21.3318q23 ( chr18:58,962,17076,114,684 ) ( fig .
these findings suggested the possibility of partial duplication of the long arm of chromosome 1 and partial loss of the long arm of chromosome 18 .
repeated chromosomal analysis with a large number of cells revealed unbalanced translocation karyotype of 46,xy , der(18)t(1;18)(q32.1;q21.3)/46,xy ( fig .
abnormalities were confirmed by fish using 1q44 and 18q23 probes . among 200 total cells , 185 cells ( 92.5% ) showed 2 red and 2 green signals , and 15 cells showed ( 7.5% ) 3 green signals and 1 red signal ( fig .
as the mother 's and father 's chromosomes turned out normal ( 46,xx and 46,xy , respectively ) , the translocation was a de novo mutation .
the patient 's first chromosomal analysis was done by gtl - banding with a banding resolution of 550 ( 20 cells ) .
the second analysis was performed after acgh analysis and was done by gtg - banding with a banding resolution of 550 ( 164 cells ) ( neodin medical institute , seoul , korea ) .
oligonucleotide - based microarray analysis was performed using a 135k cgx-3 whole - genome microarray ( roche nimblegen , madison , wi , usa ) .
genomic dna was extracted from peripheral blood , and the patient 's dna and normal control dna ( human genomic dna : male / female , promega , madison , wi , usa ) were labeled with cy3 and cy5 with a roche nimlegen dna labeling kit .
array hybridization , washing and scanning were performed as specified by the manufacturer ( roche nimblegen ) .
fluorescence in situ hybridization ( fish ) analysis of 150 metaphase and 50 interphase fish analysis were done using bacterial artificial chromosome , clone , rp11 - 370k11(1q44 ) , and rp11 - 849i 19 ( 18q23),which located regions of gain or loss .
however , abnormal signals in the brain mri and the patient 's dysmorphic face suggested chromosomal aberration syndrome .
subsequent acgh analysis revealed a subtle copy - number gain of 2,255 oligo probes spanning ~46.38 mb at 1q32.1 1q44 ( chr1:200,797,519247,174,728 ) and a subtle copy - number loss of 874 oligo probes spanning ~46.38 mb at 18q21.3318q23 ( chr18:58,962,17076,114,684 ) ( fig .
these findings suggested the possibility of partial duplication of the long arm of chromosome 1 and partial loss of the long arm of chromosome 18 .
repeated chromosomal analysis with a large number of cells revealed unbalanced translocation karyotype of 46,xy , der(18)t(1;18)(q32.1;q21.3)/46,xy ( fig .
3 ) , which indicated the 7.3% of mosaicism . abnormalities were confirmed by fish using 1q44 and 18q23 probes . among 200 total cells , 185 cells ( 92.5% ) showed 2 red and 2 green signals , and 15 cells showed ( 7.5% ) 3 green signals and 1 red signal ( fig .
4 ) . as the mother 's and father 's chromosomes turned out normal ( 46,xx and 46,xy , respectively ) , the translocation was a de novo mutation .
chromosome 18q deletion syndrome is one of the most common deletion syndromes with an estimated frequency of approximately 1/40,000 live births1 ) .
manifestations include intellectual disability , facial dysmorphism , microcephaly , stenotic ear canals , cardiac , endocrine , genitourinary , immunologic , ophthalmologic , musculoskeletal , and neurologic abnormalities .
neurologic manifestations include developmental delay , hypotonia , seizures , pyramidal and extrapyramidal signs , nystagmus , impaired coordination and white matter abnormalities on brain mri6 ) . at the deletion site ( 18q21.323 ) ,
two genes of interest at the 18q23 locus are mbp ( omim 159430 , genomic coordinates : 18:74,690,78874,844,773 ) and galr1 ( omim 600377 , genomic coordinates : 18:74,962,00774,982,097 ) .
haploinsufficiency of mbp has been considered as related with abnormal t2 signals on brain mri , suggesting dysmyelination .
as galanin is a potent stimulatory factor for gh secretion through growth hormone releasing hormone - dependent mechanisms , defect of galr1 is responsible for growth retardation in 18q - syndrome7 ) .
the european cytogeneticists association register of unbalanced chromosome aberrations ( ecaruca ) database ( www.ecaruca.net ) lists 2 patients with pure 18q21.318q23 , without complex rearrangements , among the 22 kinds of all 18q21.318q23 deletions .
clinical features include low birth weight , short stature , microcephaly , frontal bossing , hypertelorism , low set ears , small ears , upturned nose , flat nasal bridge , small mandible , hypotonia , single palmar crease , broad hands , club feet , pda , and tricuspid incompetence .
partial duplications of 1q are usually caused by unbalanced translocations and present as congenital abnormalities4 ) .
particular breakpoints are 1q21 , 1q25 , 1q32 , and 1q428 ) . among them , 1q32 to 1qter mostly involves pure partial trisomy 1q .
the ecaruca database lists 11 cases of partial 1q duplications of 1q321q44 or 1q321qter , with or without complex rearrangements . until now ,
three pure inverted or tandem duplications of 1q321q44 have been reported49 ) . in the region of 1q32.11q44 , a total of 210 omim genes are located .
major features of 1q32-qter are growth retardation , microcephaly , prominent forehead , midfacial hypoplasia , high arched palate , low - set ears , overriding toes , and micrognathia10 ) .
many of our patient 's clinical features were consistent with 18q deletion syndrome but he also displayed some features found in 1q duplication .
his cardiac abnormalities , developmental delay , and brain dysmyelination on mri were corresponded with 18q deletion syndrome .
mild facial dysmorphisms such as frontal bossing , down slanting palpebral fissure , low set ear , flat nose , and growth retardation were corresponded with both 1q duplication and 18q deletion syndromes . however ,
his white matter abnormality is a characteristic feature of mbp gene haploinsufficiency at the 18q23 locus .
our patient was initially suspected of aberration by acgh analysis , and subsequently confirmed by repeated chromosomal analysis with a large number of cells .
this case highlighted again the role of the microarray - based cytogenetic technology to cover insufficiencies of conventional cytogenetic assays .
Output:
| we report the case of a 22-month - old boy with a new mosaic partial unbalanced translocation of 1q and 18q .
the patient was referred to our pediatric department for developmental delay .
he showed mild facial dysmorphism , physical growth retardation , a hearing disability , and had a history of patent ductus arteriosus .
white matter abnormality on brain magnetic resonance images was also noted .
his initial routine chromosomal analysis revealed a normal 46,xy karyotype . in a microarray - based comparative genomic hybridization ( acgh ) analysis , subtle copy number changes in 1q32.1q44 ( copy gain ) and 18q21.3318q23 ( copy loss ) suggested an unbalanced translocation of t(1;18 ) .
repeated chromosomal analysis revealed a low - level mosaic translocation karyotype of 46,xy , der(18)t(1;18)(q32.1;q21.3)[12]/46,xy[152 ] .
because his parents had normal karyotypes , his translocation was considered to be de novo .
the abnormalities observed in acgh were confirmed by metaphase fluorescent in situ hybridization .
we report this patient as a new karyotype presenting developmental delay , facial dysmorphism , cerebral dysmyelination , and other abnormalities . |
PubmedSumm118721 | ***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:
| this review focuses on progress in the development of transport models for heterogeneous contaminated aquifers , the use of predicted contaminant concentrations in groundwater for risk assessment for heterogeneous human populations , and the evaluation of aquifer remediation technologies .
major limitations and areas for continuing research for all methods presented in this review are identified.imagesfigure 2 . |
PubmedSumm118722 | ***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: herpes simplex virus ( hsv ) , a double - stranded dna virus , is a common human pathogen , classically causing orofacial ( mostly hsv-1 ) or genital ( mostly hsv-2 ) infections .
the clinical presentation ranges from mild uncomplicated mucocutaneous infection to occasionally life - threatening , disseminated infection .
the pathogenesis follows the sequence of primary infection , latency in the local dorsal root ganglion of a sensory neuron , and reactivation [ 1 , 2 ] . of all human herpes viruses ,
about 90% of individuals between 20 and 40 years old have been shown to have antibodies against hsv-1 .
primary hsv-1 infections occur mainly in infancy or childhood and are usually mild or subclinical .
later , the virus can be reactivated spontaneously or by suppressed immunity , for example by trauma , fever , menstruation , ultraviolet radiation or immunosuppressive medication [ 1 , 2 ] .
latent hsv may be reactivated by primary immunodeficiency or treatment - induced immune suppression . in these patients extensive skin involvement
also , cases of disseminated hsv infections with internal organ involvement ( especially hepatitis ) have been described in immunocompromised patients .
a 79-year - old woman was referred to our out - patient dermatology department presenting with subacute onset , painful and itching blistering on the back .
her medical history mentioned an urothelial carcinoma which was treated by nephro - ureterectomy with lymph node dissection and adjuvant radiotherapy .
rectal blood loss due to mucosal radiation damage was treated by oral prednisone ( 20 mg daily ) maintenance therapy .
furthermore , her medical history mentioned atrial fibrillation , hypertension , depression , and arthrosis .
her medication listed carbasalate calcium , amiodarone , citalopram , domperidone , esomeprazole , fentanyl , ferrofumarate , furosemide , lactulose , lorazepam , nadroparin , oxycodone , paracetamol , and spironolactone .
clinically , multiple eroded vesicles and blisters with minimal surrounding erythema were seen on the back .
the lesions were located mostly on the left side of the back within a disseminated distribution ( fig .
two crusted erosions were present on the thorax and nose ; the oral mucosa was not affected .
the clinical differential diagnosis was herpes simplex infection , herpes zoster infection , pemphigus vulgaris or bullous pemphigoid .
the clinical working diagnosis was autoimmune blistering disorder due to the atypical distribution of the skin lesions and negative tzanck test .
the patient was treated with oral prednisone ( 1 mg / kg / day ) and class iv topical corticosteroids .
two days later , histopathology showed intra - epidermal blistering with multinucleated keratinocytes with ground glass nuclei and acantholysis .
immunofluorescence was negative for autoimmune blistering disorders . upon the diagnosis herpes simplex infection , oral and topical steroid treatment
was discontinued and oral aciclovir ( 1,000 mg 3 times daily ) and local zinc oxide were initiated .
hsv infections have been reported more often in immunocompromised patients than in immunocompetent hosts . generalized or atypical hsv infections have been described in pregnant women , neonates , with oral corticosteroid immune suppression and immunosuppression after kidney or bone marrow transplantation .
. characteristics of atypical infections in immunocompromised patients include : larger size of lesions , deeper ulceration , satellite lesions , longer healing time , hsv shedding in the saliva , and atypical locations .
atypical hsv infections in immunocompromised patients may resemble autoimmune blistering disorders like pemphigus vulgaris , pemphigus foliaceus or bullous pemphigoid .
atypical hsv infections mimicking autoimmune blistering disorders can cause diagnostic delay and delayed or incorrect treatment .
although the diagnosis of hsv infections is usually made clinically , tzanck test , electron microscopy , viral culture and polymerase chain reaction ( pcr ) detection of hsv dna can be utilized to verify the diagnosis [ 2 , 9 ] . in our case ,
the atypical clinical presentation and negative tzanck test discouraged the initial clinical diagnose of a hsv infection , resulting in the initial working diagnosis of autoimmune blistering disorder .
the tzanck test ( or direct smear ) is an easy , fast , and inexpensive diagnostic test to verify a clinical cutaneous hsv infection .
this rate is inferior to diagnostic tools like pcr and dependent upon doctors ' experience . also , the type and duration of the lesions evaluated are important for the accuracy of the tzanck test .
our negative tzanck test could be explained by suboptimal lesions ( crusted and eroded blisters ) .
immunohistochemical staining , using polyclonal antibodies with cross - reactivity between hsv-1 and hsv-2 can not differentiate between hsv-1 and hsv-2 . in our case ,
hsv-1 infection is most likely , because of the co - existence of orofacial crustae .
this case report emphasises the importance of clinical awareness of the occurrence of extensive and atypical mucocutaneous hsv infections in immunocompromised patients .
furthermore , a negative tzanck test does not rule out the presence of a hsv infection .
Output:
| immunodeficient patients are at risk of developing extended or atypical herpes simplex virus infections , which can be easily misdiagnosed .
we present the case of a 79-year - old , treatment - induced ( oral corticosteroid ) , immunocompromised female with an extensive atypical herpes simplex virus infection .
this patient presented with multiple erosions and vesicles on the trunk with a subacute onset .
the clinical differential diagnosis was herpes simplex infection , herpes zoster infection , pemphigus vulgaris or bullous pemphigoid . due to the atypical clinical presentation and negative tzanck test ,
suspicion of viral infection was low .
high - dose steroid treatment was initiated .
subsequent histopathology , however , showed a herpes simplex virus infection . after discontinuing steroid treatment and initiating antiviral treatment ,
the patient recovered within a week .
emphasis must be placed on the importance of clinical awareness of extended and clinically atypical herpes simplex infections in immunocompromised patients .
a negative tzanck test does not rule out the possibility of a herpes infection . |
PubmedSumm118723 | ***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: stroke affects quality of life through physical , mental , emotional , cognitive , and social
damage1 , 2 .
interest in improvement of quality of life and rehabilitation is
important because stroke patients suffer from various disabilities and various types of
damage3 , 4 .
the occupational performance occurs in the dynamic relationships
among occupations , roles , circumstances where they live , jobs and leisure activities5 . by focusing on occupational performance ,
occupational therapists are able to support the client to actively participate in activities
of daily living6 .
well - being is described as the state of recognizing harmony in all aspects of life :
satisfaction , pleasure , spiritual experience , and happiness .
the goal of occupational
therapy is to focus on those occupations that could maintain or improve a patient s health
and well - being7 .
the belief that
occupational performance is related to health and well - being is the basis of the fundamental
theory and practice of occupational therapy8 , 9 , and it implies that an individual s health
and well - being can be enhanced by participation in meaningful occupations10 .
however , there are few studies about the
relationship between occupational performance and well - being . furthermore , there are no
studies that have examined the relationship between occupational performance as assessed for
oneself and one s environment and well - being .
thus , the purpose of this study was to
evaluate the occupational performance of stroke patients and their environment by
occupational self - assessment and to investigate the relationship between occupational
performance and well - being .
the stroke patients participating in the study were receiving occupational therapy in the
cities of busan and gimhae , republic of korea , and there were 92 participants in total ( 61
males , 31 females ) .
the time since stroke was less than
12 months for 38 patients and more than 12 months for 54 patients .
the targeted stroke
patients were those without cognitive impairment as indicated by a score of at least 24
points on the mini - mental state examination - korean version ( mmse - k ) .
occupational self - assessment version 2.2 ( osa ) and the personal well - being index - adult
( pwi - a ) were used for evaluations .
a total of 101 questionnaires were distributed ; 9
returned questionnaires were excluded because of incomplete responses , and 92 were included .
the osa was created by baron , kielhofner , iyenger , goldhammer , and wolenski11 .
it has 29 questions divided into two
sections : 21 questions in the myself section and eight questions in the my environment
section . for the osa ,
the participant first scores his / her level of performance for each
activity on a 4-point scale
. then the participant scores the importance of each activity on
a 4-point scale .
finally , the participant indicates in order of importance 4 of the 21
myself items they would like to change , and they also do this for 2 of the 8 my
environment items .
the pwi - a was designed based on the comprehensive quality of life scale12 , and it consists of 8 items : standard of
living , personal health , achieving in life , personal relationships , personal
safety , community connectedness , future security , and
the
level of satisfaction is scored from very unsatisfied ( 0 points ) to very satisfied ( 10
points ) on an 11 point scale for each item .
a reliability survey showed that cronbach s
alpha was between 0.70 and 0.85 and that there was good test - retest reliability , with an
intra - class correlation coefficient of 0.8413 .
the pasw statistics 18.0 software was used for the analysis , and
pearson correlation analysis was applied to investigate the relationship between
occupational performance and well - being .
getting along with others ( 2.80 0.79 ) was scored highest among the 21 myself items
for occupational performance , and managing my basic needs was scored second highest .
taking care of others for whom i am responsible was scored lowest among the 21 myself
items for occupational performance ( 1.74 0.77 ) , followed by being involved as a student ,
worker , volunteer and family member . in importance ratings , taking care of myself showed
the highest score , 3.41 0.73 , followed by managing my basic needs .
the least important
item was being involved as a student , worker , volunteer and family member , the score which
was 2.83 0.83 ( table 1table 1.occupational self - assessmentmyself ( unit : scores)characteristicsperformancem sdimportancem sdi would liketo changeconcentrating on my tasks2.54 0.822.99 0.83physically doing what i need to do2.08 0.843.29 0.82taking care of the place where i live2.25
0.752.96 0.74taking care of myself2.21 0.773.41 0.731taking care of others for whom i am responsible1.74 0.772.99 0.972getting where i need to go2.24 0.913.15 0.75managing my finances2.16 0.893.00 0.86managing my basic needs2.72 0.793.40 0.66expressing myself to others2.61 0.763.04 0.71getting along with others2.80 0.793.14 0.74identifying and solving problems2.45 0.763.13 0.67relaxing and enjoying myself2.60
0.743.11 0.67getting done what i need to do2.30 0.843.27 0.59having a satisfying routine2.19 0.803.04 0.71handling my responsibilities2.31 0.853.08 0.79being involved as a student , worker , volunteer and family
member1.93 0.762.83 0.83doing activities i like2.01 0.813.09 0.69working toward my goals2.15 0.883.32 0.663making decisions based on what i think is important2.37 0.823.08 0.71accomplishing what i set out to do2.15 0.953.13
0.74effectively using my abilities2.02 0.893.15 0.714 ) . among the my environment items for occupational performance , people who do things with
me and people who support and
encourage me showed scores of 2.66 0.79 and 2.66 0.82 ,
which were the highest scores . the things i need to be productive
( 1.94 0.80 ) was the
my environment items scored lowest . similar to tendencies in performance ratings ,
people
who do things with me was scored highest ( 3.38 0.66 ) and the things i need to be
productive was scored lowest 2.99 0.74 among the environment - related importance ratings
( table 2table 2.occupational self - assessmentmy environmentcharacteristicsperformancem sdimportancem sdi would liketo changea place to live and take care of myself2.38 0.813.26 0.57a place where i can be productive ( work , study , volunteer)1.99 0.802.99 0.74the basic things i need to live and take care of myself2.29 0.733.23 0.631the things i need to be productive1.94 0.803.00 0.76people who support and encourage me2.66 0.823.34 0.70people who do things with me2.66 0.793.38 0.66opportunities to do things i value and like1.99 0.863.15 0.652places where i can go and enjoy myself2.10 0.833.10 0.65 ) . among the 8 items of the pwi - a , personal relationship
spirituality / religion and standard of living . on the other
hand ,
personal health showed the lowest satisfaction ( 3.26 2.19 ) ( table 3table 3.personal well - being index adultcharacteristicsm sdstandard of living5.13 2.18personal health3.26 2.38achieving in life4.50 2.13personal relationships5.32 2.19personal safety4.62
analysis of the correlation between occupational performance as assessed by
the myself and my environment sections of the osa and well - being revealed moderate
positive correlation .
( p<0.05 ) ( table
4table 4.correlation between occupational performance and well - beingoccupationalperformance(myself)occupationalperformance(my environment)well - being0.432 * 0.427**p<0.05 ) .
in this study , occupational performance and well - being were measured in stroke patients
through client - centered self - report questionnaires .
a significant positive relationship
between occupational performance and well - being was indicated based on analysis of the
questionnaires .
the occupational performance of getting along with others was relatively well performed ,
but that of taking care of others for whom i am responsible was not .
this implies that the
stroke patients found it difficult to implement the role of an assistant due to disability
but formed relatively better general relationships with others .
the patients identified
taking care of themselves as the most important factor and being involved as a student ,
worker , volunteer and family member as the least important factor .
a previous study showed
a similar tendency in stroke patients who focused on physical recovery and reduced effort
toward social relationships and leisure activities , resulting in incomplete restoration to
pre - stroke levels14 . among the my environment items for occupational performances ,
people who do things with
me and people who support and encourage me were scored highest , which suggested that the
stroke patients needed help from family and other people and were relatively well supported .
this support , however , could deteriorate depending on their ability to perform activities of
daily living after stroke and is an important factor that may prevent the resumption of work
and return to pre - stroke life15 .
analysis of the pwi - a date showed that the patients were most satisfied in personal
relationships and were least satisfied in personal health .
although personal relationship
was scored highest point ( 5.32 ) among the 8 items , it showed a minimal difference compared
with the other items .
personal health showed the lowest level of satisfaction because of
negative effects from physical disabilities after stroke .
in other previous studies of life
satisfaction among long - term stroke survivors , the participants indicated difficulties in
sexual activity and leisure activities and negative effects on satisfaction resulting from
the inability to participate in physical activity and other handicaps of daily living16 , 17 . the limitations of this study include that it was confined to the cities of busan and
gimhae , republic of korea , and that there were only 92 participants .
in addition , it was not
possible to examine variations in occupational performance and well - being because a
follow - up study was not been performed . despite these limitations ,
use of the osa may be
beneficial for clinical applications because it could aid in identifying the occupational
performance and abilities of individual patients , setting patient goals , and client - centered
treatment .
client - centered evaluation tools , which indicate performances , could be applied
to various people with disabilities18 .
the results of these tools could be used by physicians to understand the patient s
perspective about their own performance , and this could be applied to treatment plans19 .
further studies are needed to investigate
the long - term variation of occupational performance of stroke patients and to examine the
impact on well - being of improvement of occupational performance .
Output:
| [ purpose ] this study was performed to evaluate the occupational performance of stroke
patients and their environment by occupational self - assessment and to investigate the
relationship between occupational performance and well - being .
[ subjects and methods ] this
study enrolled ninety - two stroke patients who were receiving occupational therapy at a
general hospital , a rehabilitation hospital , or a community welfare center in the cities
of busan and gimhae , republic of korea . occupational performance and well - being
were
investigated with occupational self - assessment version 2.2 and the personal well - being
index - adult .
[ results ] analysis of the correlation between occupational performance as
assessed by the myself and my environment sections of occupational self - assessment
version 2.2 and well - being revealed moderate positive correlation for both sections .
[ conclusion ] the relationship between occupational performance and well - being was
identified .
further studies are needed to reveal whether improvement of occupational
performance could affect well - being in various dimensions . |
PubmedSumm118724 | ***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 the cardiac device implantation procedure , selection of the appropriate vein puncture site is important to reduce the risk of vascular and lead - related complications.1 ) nerve injuries that arise during device implantation procedures are sparsely reported in the literature.2)3 ) here , we report a case of brachial plexus injury caused by indwelling transvenous pacing leads .
a 64-year - old male patient underwent cardiac resynchronization therapy ( crt ) device with defibrillator implantation for dilated cardiomyopathy and recurrent ventricular tachycardia . during the implantation procedure ,
it was difficult to determine the location of the left axillary vein as although the left subclavian vein was punctured and a guide wire could be inserted , we could not insert a peel - away introducer across the costoclavicular junction and handle the inserted right ventricular lead due to mechanical resistance at the costoclavicular junction . to avoid the risk of difficult lead handling and future subclavian crush syndrome
, a second puncture was performed at a more lateral site approximately two fingers away from the initial puncture point .
although a puncture needle should be inserted almost vertically in order to reach the lateral axillary vein near the junction of the cephalic and brachial veins , we were able to insert peel - away introducers and the left ventricle ( lv ) and right atrium ( ra ) leads without any difficulty .
the lv and ra leads were positioned where the optimal values of sensing and pacing parameters were obtained . after starting biventricular pacing , the episodes of ventricular tachycardia decreased remarkably , suggesting successful electrical remodeling .
the patient was discharged without overt complications . however , two weeks after the implantation of the crt device , the patient started complaining of " electric shock - like " pain in the left axillary area radiating to the medial border of the left arm .
the patient described the pain as being usually triggered by active shoulder movements , especially when pulling up his pants . during physical examination , typical pain in the left axillary area was reproduced whenever his left shoulder was passively abducted more than 60 degrees .
chest computed tomography scans showed the lv and ra leads running together into the lateral axillary vein along the lateral side of the pectoralis minor muscle causing a curvature with an acute angle ( fig .
fluoroscopic examination in the supine position showed that the lv and ra leads were positioned at an acute angle directing towards the left brachial plexus whenever the patient 's shoulder was passively abducted more than 60 degrees ( fig .
2 ; video in the online - only data supplement ) . severe left axillary and radiating arm pain recurred whenever the lv and ra leads formed such an acute angulation on fluoroscopic examination .
analgesics and antibiotics were prescribed to control the pain and to treat the possible subclinical device - related infection .
however , the patient complained of gradual worsening of the pain despite continued administration of high - dose pain killers .
six months after implantation of the crt device , the patient was readmitted for adjustment of lead angulation due to worsening of the left axillary and radiating arm pain which impeded the patient 's daily physical activities . due to the fact that the lv and ra leads were inserted across the pectoralis major and minor muscles into the lateral axillary vein , which was located deep in the patient 's chest , correction of the lead angulation by generator repositioning was technically impossible .
operators had to move the entry site of the lv and ra leads from the distal to the proximal axillary vein using the cut - down method .
under general anesthesia , the pectoralis minor muscle was cut and the axillary vein was exposed .
after disconnection of the lv and ra leads from the generator , we attempted to manually extract the disconnected leads through the transverse incision line .
however , the leads were tightly adhered to the axillary venous wall , and the possibility of vascular injury and lv lead malpositioning due to extraction force was considered . finally , we had to open the left axillary vein to separate the leads safely .
the left axillary vein was incised longitudinally from the initial insertion site of the lv and ra leads to the more proximal site which was 3 cm away ( figs . 2d and 3b ) .
separated leads were moved to the proximal site through the longitudinal incision line and the remaining incision lines were closed . after adjusting the lv and ra lead insertion site ,
acute angulation was not observed during passive shoulder abduction more than 60 degrees on fluoroscopic examination ( fig .
although curvatures of the lv and ra leads were slightly modified after the correction surgery , there was no significant change in the lv lead tip location and lv capture threshold .
neuropathic pain decreased remarkably two weeks later and analgesic agents could be withheld two months later .
the ranges of passive and active shoulder movements increased gradually but were nearly completely normalized at six months after the surgery .
during the cardiac device implantation procedure , selection of the appropriate vein puncture site is important to avoid the risk of vascular or pacing lead - related complications.1 ) in the present case , to avoid the risk of subclavian crush syndrome , the lv and ra leads were inserted into the lateral axillary vein which is close to the brachial plexus , under the guidance of contrast venography.4 ) unfortunately , the inappropriately inserted crt device leads caused brachial plexus injury .
although transvenous pacing lead - induced nerve injury is not a frequent complication seen in clinical practice , this possibility should be kept in mind by the operators .
if this type of complication occurs , correction surgery for the lead insertion site using the cut - down method can be considered as a therapeutic option .
understanding the vascular anatomy with adjacent nerve structures and carefully selecting the vein puncture site are necessary for minimizing the risk of pacing lead - induced nerve injury .
Output:
| a 64-year - old male patient underwent cardiac resynchronization therapy ( crt ) device implantation via the axillary venous approach .
two weeks later , the patient started complaining of " electric shock - like " pain in the left axillary area . during physical examination , typical pain in the left axillary area
was reproduced whenever his left shoulder was passively abducted more than 60 degrees .
fluoroscopic examination showed that the left ventricle ( lv ) and right atrium ( ra ) leads were positioned at an acute angle directing towards the left brachial plexus whenever the patient 's shoulder was passively abducted .
brachial plexus irritation by the angulated crt leads was strongly suspected . to relieve the acute angulation , we had to adjust the entry site of the lv and ra leads from the distal to the proximal axillary vein using the cut - down method .
after successful lead repositioning , the neuropathic pain improved rapidly .
although transvenous pacing lead - induced nerve injury is not a frequent complication , this possibility should be kept in mind by the operators . |
PubmedSumm118725 | ***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: chlamydia trachomatis , an obligate intracellular bacterium , is worldwide a common cause of sexually transmitted infections .
since 1995 , the number of c. trachomatis infections has been officially notified in finland , and the number of notifications has been increasing . lately , there has been around 14 000 notified cases annually ( 250 cases/100 000 inhabitants ) . in finland , c. trachomatis infections are diagnosed mainly with sensitive and specific nucleic acid amplification tests ( naats ) , but these tests do not differentiate between genotypes . the seroimmunological analysis of c. trachomatis major outer membrane protein ( momp ) first leads to the identification of 15 different serovars , and sequence differences in the ompa gene , especially in the areas coding the variable domains of momp , later confirmed this discrimination [ 3 , 4 ] . c. trachomatis types a c cause trachoma , types d k cause urogenital infections , and types l1l3 cause lymphogranuloma venereum ( lgv ) . c. trachomatis has also a cryptic plasmid which is commonly used as a target sequence in diagnostic naats . in 2006
, there was an unexpected fall in c. trachomatis cases in sweden , which was caused by the appearance of a new variant of c. trachomatis ( nvct ) with a 377 base pair deletion in the cryptic plasmid .
at the same time , the proportion of urogenital samples that tested positive by cobas taqman ct test , old version ( roche ) , decreased slightly in southern finland ( dr . jukka suni , huslab ; personal communication ) .
the purpose of this work was to set up a real - time pcr - based method for genotyping c. trachomatis ( types d k and l1l3 ) in urogenital samples .
additionally , we wanted to set up a method for detection of the swedish nvct and to study the occurrence of this variant in finland .
in 2008 , 160 unselected c. trachomatis positive specimens from females and males were collected for genotyping .
the first - void urines ( n = 82 ) , cervical / vaginal swabs ( n = 75 ) , and conjunctival swabs ( n = 3 ) had been sent to huslab , department of virology for c. trachomatis nucleic acid testing .
huslab , the diagnostic laboratory of the helsinki university central hospital serving the capital area , used at that time both aptima combo 2 assay ( gen - probe ) and cobas taqman ct test ( roche ) . of the 160 samples ,
additionally , 38 c. trachomatis negative clinical samples were included as negative controls . to estimate the prevalence of the swedish nvct in finland ,
469 were c. trachomatis positive with aptima combo 2 assay ( gen - probe ) ( n = 414 ) or cobas taqman ct test , new version ( roche ) ( n = 55 ) , and 26 were negative with cobas taqman ct test , old version ( roche ) .
as the prevalence of the nvct at that time was quite high in sweden , we initially planned to collect specimens that tested c. trachomatis negative by the old version of the cobas taqman ct test ( roche ) , which fails to detect them .
however , the test was soon replaced by a new dual - target version by the manufacturer , and the majority of our material consisted of c. trachomatis positive specimens . for genotyping ,
dna was extracted from a specimen volume of 400 l with magna pure compact instrument ( roche ) using magna pure compact nucleic acid isolation kit i ( roche ) with dna bacteria protocol and eluted in 50 l . for detection of the nvct
, dna was extracted from a specimen volume of 200 l with magna pure lc ( roche ) instrument using magna pure lc dna isolation kit i ( roche ) with dna i blood cells high performance protocol and eluted in 100 l .
the concentration of total dna was measured with a nanodrop 1000 spectrophotometer ( thermo scientific ) .
the method is based on the sequence variation of the ompa gene , and it has two primer sets and eleven genotype - specific taqman probes for types d k and l1l3 . in this study , we used the non - nested version of the method . as controls , dna extracted from c. trachomatis reference strains ( types a k and l2 ) originally from atcc ( american type culture collection ) propagated in mccoy cells ( mouse fibroblast cells ) was used . to screen for the swedish nvct
this method has primers and a taqman probe flanking the deletion sequence in the cryptic plasmid of c. trachomatis .
a clinical sample containing the nvct , kindly provided by professor bjrn herrmann , uppsala , sweden , was used to construct a positive control for the assay .
the sequence flanking the deletion was amplified and cloned into a plasmid vector with zero blunt topo pcr cloning kit ( invitrogen life technologies ) according to the manufacturer 's instructions .
plasmids were extracted with qiaprep spin miniprep kit ( qiagen ) , and the dna concentration was measured with a nanodrop 1000 spectrophotometer ( thermo scientific ) .
real - time pcr analyses were performed with an abi 7500 instrument and sequence detection software version 1.3.1 ( applied biosystems ) .
the primers and probes used in this study were purchased from applied biosystems , metabion international ag , or tag copenhagen a / s .
the pcr reactions were performed in a 25 l volume containing 250 nm primers , 100 nm probes , and either 12.5 l platinum quantitative pcr supermix - udg ( invitrogen life technologies ) or 12.5 l taqman universal master mix ( applied biosystems ) .
thermal cycling conditions were , 50c 2 minutes , 95c 10 minutes and 40 cycles of 95c 15 seconds and 60c 1 minute .
template volume was 2 l or 5 l for genotyping and 2 l from two different samples pooled together for detection of the nvct .
of the 160 c. trachomatis positive clinical samples analyzed , 144 ( 90% ) could be genotyped .
ninety % of both first - void urines and swab samples sent for naat contained enough chlamydial dna for the ompa pcr .
sixteen samples ( 10% ) remained without a genotype with the non - nested version of the used method which was most likely due to the low amount of chlamydial dna present in the specimens .
genotypes e ( n = 57 , 40% ) , f ( n = 41 , 28% ) , and g ( n = 19 , 13% ) were the most prevalent in this study and comprised together over 80% of the c. trachomatis findings .
the 16 samples that remained negative for genotypes d k were analyzed for genotypes l1l3 .
all the 38 c. trachomatis negative clinical samples tested also negative in genotyping pcr . among the 469 c. trachomatis positive clinical samples screened for the swedish nvct , samples from two female patients were found to contain a bacteria with the variant plasmid ( 0.4% ) .
one of the samples was first - void urine and the other a vaginal swab .
both of the nvct were of genotype e , as has been described also in sweden and elsewhere [ 6 , 21 ] .
both also harbored a cryptic plasmid with a deletion site in the orf1 , and the sequence flanking the deletion in both strains was identical to that of the swedish nvct ( confirmed by sequencing ) .
the clinical samples containing the nvct were both initially tested by the aptima combo 2 assay ( gen - probe ) that is based on detection of the ribosomal rna and is thus able to detect also this type of variant c. trachomatis .
typing of c. trachomatis strains can be used in epidemiologic surveillance locally or internationally , to assess the changes in genotype distribution and to reveal transmission patterns in sexual networks .
it potentially also assists in understanding the pathogenesis of these infections for example , whether genotypes are associated with clinical phenotypes or clearance of infection or differentiating between new , repeated , and persistent infection [ 23 , 24 ] .
this information is elementary in efforts to monitor and prevent spread of c. trachomatis infections .
typing of c. trachomatis has traditionally been based on differences in momp or the ompa gene coding it . lately , also high - resolution genotyping for c. trachomatis [ 24 , 25 ] has been developed .
these novel methods could be advantageous especially when strains from a geographically localized area or from a population where certain ompa genotypes dominate are analyzed . of the unselected c. trachomatis positive specimens sent to the diagnostic laboratory for naat , 90% contained enough dna to allow genotyping . based on an ompa pcr , the most prevalent c. trachomatis genotypes in finland were e , f , and g comprising approximately 80% of the strains that could be typed . the proportion of types f and g seems to have increased whereas the proportion of types d and e seems to have remained rather stable , when set against the typing results from 1987 ( monoclonal antibodies ) and 1996 ( ompa pcr and restriction fragment length polymorphism , rflp ) .
although the different methods used in these studies and the relatively small numbers of strains typed could partly explain the observed differences , these might be true changes . indeed ,
also in seattle , washington , with a method based on monoclonal antibodies , a similar change was reported : the proportion of infections due to serovars f and g increased in 19881996 . when the type distribution in europe ( finland , sweden before the appearance of the nvct [ 12 , 13 ] , the netherlands [ 14 , 15 ] , and portugal ) and in the usa [ 1720 ] was evaluated , the proportion of types e and g tended to be slightly lower in the usa than in europe , while the proportion of types j / ja and i / ia seemed somewhat higher in the usa than in europe . again , the typing methods varied ( see table 2 ) .
however , when the european data is compared to that obtained with ompa sequencing in the usa , the aforementioned observations still remain [ 19 , 20 ] .
although the typing method used also detects genotypes l1l3 , we did not detect any l types among the urogenital specimens tested .
classic lgv infections caused by genotypes l1l3 have been uncommon in the western countries , including finland . however , lately outbreaks of proctitis caused by type l2 among hiv - positive msm have been reported in many european countries .
certain c. trachomatis sero-/genotypes have been linked to certain clinical features for example abdominal pain , pelvic inflammatory disease , and pregnancy complications , but also to asymptomatic infections [ 18 , 22 , 2729 ] . as the associations remain weak at best , it is not likely that typing ompa or ompa encoded protein momp of the urogenital strains will reveal clues to their pathogenicity .
classification relying on other , yet unidentified virulence attributes might better reflect associations of certain c. trachomatis subgroups with disease severity , persistence , or asymptomaticity .
the emergence of the swedish nvct has clearly pointed out the importance of epidemiologic surveillance and attentive evaluation of results obtained using diagnostic test kits .
as the cryptic plasmid is not absolutely essential for survival of c. trachomatis , mutations in the plasmid genes can even lead to a selection advantage for c. trachomatis . in this study
, we were able to find only two clinical samples with the swedish nvct , which was expected : only few cases outside sweden have been reported and most often the cases were linked to sweden .
unfortunately , we could not obtain information on our patients whether they had contacts to sweden because they were both lost from follow - up .
although the decrease in the positivity rate by the cobas taqman ct test , old version ( roche ) , in a major finnish diagnostic laboratory could not be explained by the appearance of nvct , this exercise has considerably improved our ability to detect novel variants .
in this study , we showed that the most prevalent genotype in finland was e ( 40% ) .
however , the swedish variant was rare in finland despite our close proximity to sweden and the frequent occurrence of genotype e.
Output:
| our aims were to genotype chlamydia trachomatis strains present in urogenital samples and to investigate the occurrence of the swedish new variant of c. trachomatis in finland .
we genotyped 160 c. trachomatis positive samples with ompa real - time pcr and analyzed 495 samples for the new variant .
the three most prevalent genotypes were e ( 40% ) , f ( 28% ) , and g ( 13% ) .
only two specimens containing bacteria with the variant plasmid were detected .
it seems that in finland the percentage of infections due to genotypes f and g has slightly increased during the last 20 years .
genotypes e and g appear to be more common , and genotypes j / ja and i / ia appear to be less common in europe than in the usa .
although the genotype e was the most common genotype among c. trachomatis strains , the new variant was rarely found in finland . |
PubmedSumm118726 | ***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 cord injury ( sci ) is a detrimental condition that affects mostly young adult individuals ( national sci statistical center , 2014 ) .
patients with this condition are subject to drastic changes in their lifestyle , as well as economic stress . after the trauma to the cord ,
several events take place at the lesion epicenter and surrounding areas ( rostral and caudal ) .
these changes start from the first millisecond to months after the lesion , and this eventually lead to the clinical symptoms that are observed in the patient . among these symptoms
are the loss of body functions such as voluntary muscle movement rendering the patient paraplegic or tetraplegic ( depending on the location of the injury ) , lack of somatosensory information , decreased breathing capacity , limited bowel and bladder control , and in some situations development of chronic pain .
sci is initiated by the physical impact to the cord that triggers molecular and cellular changes immediately after injury resulting in an acute phase where necrosis , axotomy , damage to blood vessels , ischemia , excitoxicity , increase in the production of free radicals and edema occurs ( hulsebosch , 2002 ) .
inflammation follows necrosis , facilitating axonal degeneration and demyelination at the lesion epicenter ( donnelly and popovich , 2008 ) . in the chronic phase
, further inflammation and demyelination continues , as well as programmed cellular death ( apoptosis ) , reactive gliosis and the formation of a gliotic scar ( hulsebosch , 2002 ; fitch and silver , 2008 ) .
neuroprotective compounds are necessary to reduce the number of dead cells ( neurons , astrocytes and/or oligodendrocytes ) at the lesion epicenter and surrounding areas , and regenerative drugs are needed to promote axonal outgrowth ( by either increase in the sprouting and/or regeneration process ) across the damaged region .
axonal outgrowth could be achieved by either promoting or stimulating neurite outgrowth or by reducing or blocking the expression of repulsive / repellent factors at the injury site .
therefore , multi - active drugs are required to target most of the cellular events initiated by the physical insult to the spinal cord and as a result may result in some functional locomotor recovery .
the use of estradiol as a neuroprotective hormone is very well known in central nervous system conditions like cerebral stroke , brain trauma and spinal cord injury ( dhandapani and brann , 2002 ; yune et al . , 2004 ; sribnick et al . , 2005 ; garcia - segura and balthazart , 2009 ; arevalo et al . , 2010 ;
this hormone promotes cell survival either by an increase in the expression of anti - apoptotic genes ( segarra and lee , 2004 ; scott et al . , 2012 ) or by a decrease in pro - apoptotic genes ( chaovipoch et al . , 2006 ; sribnick et al . ,
2006 ) , resulting in some functional locomotor recovery ( sribnick et al . , 2010 ) .
several investigators propose that the phenol hydroxyl ring provides antioxidant and anti - inflammatory activities ( sugioka et al .
however , the mitogenic effect of estradiol in tissues like breast and uterus , deep vein thrombosis or pulmonary embolism restricts the use of this hormone as a therapeutic drug for spinal cord injury patients ( cummings et al . , 2002 ; sare et al . , 2008 ; lalibert et al . ,
therefore , the consideration of tamoxifen as a neuroprotective and regenerative drug is under investigation in our laboratory and others ( don carlos et al . , 2009 ; tian et al . , 2009 ;
tamoxifen is a selective estrogen receptor modulator ( serm ) and an fda approved drug that interacts with estrogen receptors , producing estrogenic or anti - estrogenic effects .
the final outcome depends on the target tissue and the expression of co - activators or co - repressors that interact with the activated estrogen receptor ( mcdonnel and wardell , 2010 ) . for this reason
, tamoxifen is used mostly for the treatment of cancer , due to its antagonistic activity in tissues like breast and uterus . on the other hand
, tamoxifen acts as a neuroprotective drug in pathologies like amyotrophic lateral sclerosis ( traynor et al . , 2006 ) , ischemic brain injury ( dhandapani and brann , 2002 ; kimelberg et al . , 2003 ; mehta et al . , 2003 ; zhang et al . , 2007 ) and spinal cord injury ( tian et al . , 2009 ; ismailoglu et al . , 2010 ;
tamoxifen reduces the edema formation in adult rats after sci and results in some locomotor recovery ( tian et al .
this compound crosses the blood brain barrier ( biegon et al . , 1996 ) and could produce some behavioral improvement through a reduction in several molecular / cellular mechanisms related to the formation of reactive oxygen species , inflammatory molecules or the formation of reactive astrocytes ( zhang et al .
, 2007 ; barreto et al . , 2009 ; arevalo et al . , 2011 ;
in our laboratory , we observed an improvement in functional locomotor behavior when ovariectomized female rats were treated with tamoxifen .
significant changes were observed in the basso , beattie and bresnahan ( bbb ) open field test ( mosquera et al . , 2014 ) , as well as in the number of animals that crossed the round beam test at 7 , 14 , 21 and 28 days post injury ( figure 1 ) .
the narrow beam crossing test was used to monitor the contribution of equilibrium and balanced posture ( mediated through the vestibulospinal and propioception related tracts ) on walking .
rats crossed a 3 feet long round bar ( 2.5 cm diameter ) suspended about 15 inches from the ground ( merkler et al . , 2001 ) .
the percent of rats in each group able to cross the bar after sci , with or without the use of their hindlimbs , was determined weekly .
estradiol and tamoxifen treated rats showed a significant higher capacity for crossing the round beam at 7 , 14 , 21 and 28 days post injury than non - treated control group .
fifty percent of the rats in the estradiol ( n = 12 ) and tamoxifen ( n = 10 ) groups were able to cross the round beam without paw positioning but maintaining some balance by the first week .
in contrast , less than 0.01 % of the control rats ( n = 13 ) were able to cross the beam .
this pattern was kept until the 4 week where 75% of the estradiol - treated rats were able to cross the beam with or without paw positioning and only 0.2% of the control group crossed .
the locomotor recovery was associated with an increase in the amount of white mater spared tissue and a decrease in the superoxide activity ( mosquera et al . , 2014 ) .
estradiol or tamoxifen may upregulate the expression of glutathione and/or superoxide dismutase proteins , or these multi - active compounds could work as free radical scavengers to reduce reactive oxygen species after trauma to the spinal cord ( prokai and simpkins , 2007 ) .
post - treatment experiments demonstrated that tamoxifen administration after sci produced a significant locomotor recovery in the bbb open field test and beam crossing test , and this effect is related to an increase in the amount of spared tissue , increase in neurofilament immunoreactivity caudal to the lesion epicenter and reduction in the reactive gliosis ( unpublished results : colon et al . ,
additional mechanisms that may explain the locomotor improvement by tamoxifen administration after sci could be a reduction in the edema , a diminution in the apoptotic process , a decline in the production of inflammatory cytokines ( tnf & il-1 ) , and a decrease of myelin loss and inhibitory proteins ( tian et al . , 2009 ;
ismailoglu et al . , 2010 ; liu et al . , 2010 ; guptarak et al . ,
similar results with tamoxifen were observed after brain injury and cerebral ischemia ( zhang et al .
, 2007 ; liu et al . , 2010 ; franco - rodriguez et al .
, 2013 ; sun et al . , 2013 ) . therefore , tamoxifen ( an fda approved drug ) should be considered as a neuroprotective agent to treat spinal cord injury conditions ( figure 2a ) .
estradiol and tamoxifen ( tam ) improve the behavioral performance of injured rats in the beam crossing test .
ovariectomized rats were treated with estradiol ( 3 mg ) or tamoxifen ( 15 mg ) , either by silastic tubing or commercial pellets , respectively , 1 week prior to spinal cord injury .
the injured rats were tested weekly and the number of rats that crossed the narrow beam was analyzed with analysis of varivance followed by bonferroni post hoc test .
results demonstrated a significance difference between control ( n = 13 ) and treated ( estradiol : n = 12 ; tam : n = 10 ) animals ( * p < 0.0016 )
tam ( a ) and pp2 ( b ) are drugs that in a moderate spinal cord injury act as neuroprotective and neuroregenerative agents that promote functional locomotor recovery and increase spared white matter tissue .
increase ; decrease ; tam : tamoxifen ; pp2 : src kinase inhibitor ; ros : reactive oxygen species ; nf : neurofilament ; neun : neuronal transcription factor ; 5ht : 5-hydroxytryptamine ; bbb : blood brain barrier ; gap-43 : growth associated protein 43 ; gfap : glial fibrillary acidic protein .
investigators are attempting to enhance axonal outgrowth after spinal cord injury either by infusing factors that promote / stimulate neurite outgrowth ( lu and tuszynski , 2008 ) or by blocking the factors that have a non - permissive / repulsive effect on regeneration or sprouting ( bouquet and nothias , 2007 ) .
oligodendrocytes and reactive astrocyte produce these repellent factors . among the repulsive factors are nogo , mag , omgp , chondroitin sulfate and the eph receptors ( chen et al . , 2000 ;
wilson et al . , 2002 ; grados - munro and fournier 2003 ; mcgee and strittmatter 2003 ; fitch and silver , 2008 ) .
the complex intracellular signaling by which these proteins hold their effects is through activation of kinases that promote growth cone collapse . the aforementioned nogo - a is activated by src ( yokoyama et al . , 2006 ) and
the signaling cascade activated by epha receptors after ligand binding also requires src activation to induce the repulsive activity ( knoll and drescher , 2004 ) .
the src - tyrosine kinases ( sfks ) , is the largest family of non - receptor tyrosine kinases .
the sfks are widely expressed in many cell types and in different subcellular compartments ( thomas and brugge , 1997 ) .
sfks induce cellular responses associated with proliferation , growth control , survival , differentiation and cytoskeletal arrangements ( thomas and brugge , 1997 ; kalia et al . , 2004 ; zhao et al . ,
sfks can be switched from an inactive to an active state through control of its phosphorylation state , or through protein interactions .
sfks are the meeting point of several signaling pathways associated with neuropathologies like stroke , alzheimer 's disease , epilepsy and central nervous system trauma ( lennmyr et al . , 2004 ;
jadhav et al . , 2007 ; liang et al . , 2009 ; liu et al . ,
this family of kinases can phosphorylate or mediate the activation of central nervous system proteins such as epidermal growth factor ( egf ) , extracellular regulated kinase ( erk ) , eph , nogo , myelin associated glycoprotein ( mag ) ( thomas and brugge , 1997 ; georgakopoulos et al .
, 2006 ; yokoyama et al . , 2006 ; slack et al . , 2008 ;
after intracerebral hemorrhage in the striatum , blockade of sfks with pp1-inhibitor , decreased the number of tunel - stained cells and reduced behavioral abnormalities ( ardizzone et al .
in addition , the activation of sfk mediates changes in the blood brain barrier permeability and promotes edema by phosphorylation of metalloproteinase , tight junction proteins and other bbb proteins .
the access of sfk inhibitors , like pp1 and pp2 , to the endothelial cells from rat brain after its systemic administration inhibits post - ischemic src activation and vascular leakage , which resulted in the reduction of brain edema ( liang et al . ,
moreover , several studies in the adult spinal cord focus in the pain mediated by src after nerve injury .
the induced neuropathic pain by transection of spinal nerve appears to be related to n - methyl - d - aspartate receptor ( nmda ) receptor currents potentiated by sfks ( katsura et al . , 2006 ) .
the nerve injury induces activation of sfks in microglia of the dorsal root ganglion but also in the spinal cord .
this activation contributes to the development of hypersensitivity to mechanical stimulation that has been associated to an increased erk phosphorylation in microglia but not with astrocytes or neurons .
ephrinb2 induces tyrosine phosphorylation of the nmda receptor-2b subunit via sfks ( slack et al . , 2008 ) .
in the spinal cord , sfks are also involved in the repulsion of the axonal growth cone during development ( thomas and brugge , 1997 ; kalia et al . , 2004 ) .
sfks , as mentioned before , has been related to the activation of nmda receptor and inflammatory pain but also to the early inflammatory response mediated by uncontrolled microglia stimulation .
histological evidence from spinal cord tissue treated with 1-(1,1-dimethylethyl)-3-(4-methylphenyl)-1h - pyrazolo[3,4-d ] pyrimidin-4-amine ( ppi ) after 10 minutes of compression show a decrease in the edema , macrophage infiltration and inflammation ( akiyama et al . , 2004 ) .
sfks have also been associated with secondary damage after injury ( akiyama et al . , 2004 ) . during secondary damage
, the activation of sfk mediated by vascular endothelial growth factor ( vegf ) , leads to stimulation of endothelial cells survival , angiogenesis and edema ( akiyama et al . ,
2003 ) . in terms of neuroprotection , the inhibition of sfks reduced and restricted the macrophages infiltration to the lesion area as early as 3 days after injury ( akiyama et al . , 2004 ) . in models of cerebral ischemia and surgically induced brain injury , as occur in spinal cord injury , blockade of sfk prevented vegf - mediated signaling and vascular leakage , reduction in brain edema and decreased breakdown of the blood brain barrier ( jadhav et al .
deposition of fibrinogen in the central nervous system after damage to the blood brain barrier , either after a spinal cord transection or contusion , inhibits neurite outgrowth through sfk activation ( schachtrup et al . , 2007 ) . until now
, no study has elucidated the action of sfks in long - term recovery after spinal cord injury . in our laboratory , we have demonstrated with histological , immunohistochemical and behavioral studies that long - term blockade of sfks with pp2 in lesioned rats not only produced long - term functional locomotor recovery , but also augmented spared tissue and increased serotonin fibers caudal to the lesion epicenter ( rosas et al . , 2014 ) .
animals treated with pp2 after sci presented higher scores in the bbb open field test and also demonstrated a better performance in the beam crossing test ( rosas et al . , 2014 ) .
in contrast to other studies related to neuropathic pain , the effect of pp2 in locomotor recovery was not associated with a reactive gliosis response or the amount of microglial cells present at the injury site .
we suggest that phosphorylation of ephexin1 by src kinase after spinal cord injury may be involved in the collapse of axonal growth cones , as has been demonstrated during cns development after epha receptor ( knll and drescher , 2004 ) , generating a repulsive microenvironment at the injury site . when pp2 was administered to the injured rats the level of sfks activation was reduced and the activation of ephexin1 decreased , resulting in a better environment for axonal outgrowth . because sfks are associated with different events present after spinal cord injury , more studies are necessary to elucidate other key elements upstream or downstream in its signaling cascade that leads to inhibition of locomotor recovery .
these drugs demonstrated their neuroprotective actirity because of their effect in functional locomotor recovery and increased spared tissue after sci .
decrease in ros , inflammation and apoptosis are possible mechanisms regulated by tam ( figure 2a ) .
however , additional studies are required to determine which genes are activated in these cellular processes . moreover , if tamoxifen also provides some regenerative activity and the proteins involved in any axonal outgrowth are also unclear .
blockade of src activation with pp2 demonstrated , in the other hand , some regenerative activity due to an increase in serotonin fibers caudal to the lesion epicenter ( figure 2b ) .
although some molecular mechanisms have been related to tamoxifen and pp2 activity after sci , further experiments are warranted to establish the role of these drugs in the activation of anti - apoptotic genes , downregulation of pro - apoptotic proteins , changes in the expression of proteins that may generate a repulsive environment for axonal regeneration and expression of cytoskeletal proteins related to neurite outgrowth . moreover , in order to determine the future use of tamoxifen or sfk inhibitors ( pp1 or pp2 ) for the treatment of human spinal cord injury , more studies should be aimed to determine the optimal doses and therapeutic window for their use .
finally , the spinal cord injury field should consider the neuroprotective and neuroregenerative effects associated with the concomitant use of both drugs ( tamoxifen and pp1/pp2 ) as a therapy for sci .
Output:
| spinal cord injury ( sci ) is a devastating condition that produces significant changes in the lifestyle of patients .
many molecular and cellular events are triggered after the initial physical impact to the cord .
two major phases have been described in the field of sci : an acute phase and late phase .
most of the therapeutic strategies are focused on the late phase because this provides an opportunity to target cellular events like apoptosis , demyelination , scar formation and axonal outgrowth . in this mini - review , we will focus on two agents ( tamoxifen and a src kinase family inhibitor known as pp2 ) that have been shown in our laboratory to produce neuroprotective ( increase cell survival ) and/or regenerative ( axonal outgrowth ) actions . the animal model used in our laboratory
is adult female rat ( ~250 g ) with a moderate contusion ( 12.5 mm ) to the spinal cord at the t10 level , using the mascis impactor device .
tamoxifen or pp2 was administered by implantation of a 15 mg pellet ( innovative research of america , sarasota , fl , usa ) or by intraperitoneal injections ( 1.5 mg / kg , every 3 days ) , respectively , to produce a long - term effect ( 28 days ) .
tamoxifen and the src kinase inhibitor , pp2 , are drugs that in rats with a moderate spinal cord injury promote functional locomotor recovery , increase spared white matter tissue , and stimulate axonal outgrowth .
moreover , tamoxifen reduces the formation of reactive oxygen species .
therefore , these drugs are possible therapeutic agents that have a neuroprotective / regenerative activity in vertebrates with sci . |
PubmedSumm118727 | ***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: ( ro5 )
has had a profound impact on the build - up of small molecule screening
collections , as it delineates chemical space that is more likely to
yield cell permeable compounds and allow oral administration .
however ,
finding ro5 compliant ligands for targets with extended binding sites ,
e.g. , proteases and peptidic gpcrs , as well as protein protein
interactions has turned out to be a major challenge .
instead , modulation
of these targets often requires ligands substantially differentiated
from traditional small molecule screening collections by having properties
at the border of the ro5 or beyond ( bro5 ) .
attention
has therefore been focused on strategies for lead generation such
as natural - product - derived approaches and diversity - oriented
synthesis ( dos ) .
it is uncertain how physicochemical
properties apply to the cell
permeability of natural - product- or dos - derived compounds , especially
when the compound s properties are at , or beyond , the border
of ro5 .
understanding the key properties for design of pharmacodynamically
active compounds in this space , which are also able to penetrate cells
and modulate intracellular targets , is therefore a key challenge .
interestingly , extensive studies of the immunosuppressant cyclosporin
a , a cyclic peptide with properties far outside ro5 , have revealed
it to be conformationally flexible which allows shielding of polarity
through intramolecular hydrogen bonding .
most likely ,
this explains the unexpectedly high bioavailability of cyclosporin
a , which consequently can be administered orally .
recent studies of cyclic tri- and hexapeptide model systems also showed that intramolecular hydrogen bonding may contribute
to druglike membrane permeability . in a few cases intramolecular hydrogen
bonding
has also been found to improve the membrane permeability and
oral bioavailability of traditional small molecule drug candidates
with ro5 compliant properties . in order to capitalize on the opportunities
for modulation of challenging
targets ,
the broad institute has created a small molecule screening
collection through a diversity - oriented synthesis ( dos ) strategy .
the dos screening library consists of > 100 000
novel , discrete compounds with a fraction of sp centers
( fsp ) and stereochemical
diversity more consistent with those of natural products than traditional
ro5 screening libraries .
furthermore ,
the dos library is composed of a complete matrix
of stereoisomers as a result of being assembled through a build / couple / pair
strategy .
this modular synthetic approach and complete coverage of
stereoisomers provide a unique opportunity to systematically dissect
the factors controlling cell permeability and oral bioavailability
for natural product - like compounds with properties at or beyond ro5 . a high - throughput screening campaign with the broad s dos
screening library identified lactams 18 ( table 1 ) as novel
growth inhibitors of the recombinant tulahuen strain of t.
cruzi , with potencies ( ic50 ) for individual stereoisomers ranging from 1 nm to 0.5 m .
the key structural features of 18 include an eight - membered fused ring system , three stereocenters ,
and physicochemical properties at the border of the ro5 ( table 1 ) .
medicinal chemistry efforts and structure activity
relationships have been described elsewhere . however , in the profiling of stereoisomers 18 the solubility was found to vary greatly depending on the
stereochemical relationship of c8 and c9 , with trans - c8,c9 diastereomers
being 12 m in phosphate buffered saline ( pbs ) and the
cis - c8,c9 stereoisomers having an almost 100-fold higher solubility .
herein , we conduct detailed studies of 18 with regard to lipophilicity , pka , and cell permeability to investigate this unexpected finding further .
we observed major stereospecific differences in the experimental parameters
and report our successful efforts to explain the contributing factors
to these differences .
our findings suggest rational strategies for
modulation of cell permeability for natural - product - like compounds
that have properties at or beyond ro5 .
when the
lipophilicities of 18 were measured ,
this again revealed that the compounds clustered
into two groups depending on the stereochemical relationship of c8
and c9 ( figure 1a ) .
stereoisomers with a cis - c8,c9
relationship ( 58 ) , which were of
higher solubility , possessed log d values of
3.43.9 , while the trans - c8,c9 stereoisomers ( 14 ) had log d values that
were 0.41.1 units higher . in line with these findings , increased
epithelial permeability through a caco-2 cell monolayer was observed
for the stereochemical cluster with higher log d , while a lower permeability was found for the low log d cluster ( figure 1b ) .
the cellular
permeability was determined both with a ph gradient from 6.5 on the
apical side of the cellular monolayer to a ph of 7.4 on the basolateral
side and with a ph of 7.4 on both sides of the monolayer .
the former
is a common model for uptake from the small intestine into the bloodstream ,
mimicking the upper intestinal ph gradient , whereas the latter reflects
the transition from the bloodstream into most tissues .
in contrast ,
cis - stereoisomers 58 demonstrated
a significant increase in permeability with a ph of 7.4 on the apical
side ( orange diamonds ) , although the total values were still significantly
lower than for 14 .
the ratio between
the permeability from the basolateral to apical side of the cell monolayer
and the permeability in the opposite direction ( ph 7.4 on both sides ) ,
i.e. , the efflux ratio , varied from 0.31 to 0.48 ( table si 5 ) .
thus , the cell permeabilities determined
for the eight stereoisomers were not significantly influenced by efflux .
( a ) solubility
versus lipophilicity ( log d , ph 7.4 ) for compounds 18 .
( b )
permeability ( caco-2 papp(ab ) ) versus
lipophilicity ( log d ) for 18 , determined with a ph gradient of 6.5 ( apical ) to 7.4 ( basolateral )
between the two sides ( green squares for 18 ) and with a ph of 7.4 on both sides ( orange diamonds ) .
on the basis of the ph dependencies in the permeability assay ,
we hypothesized that the differences in solubility , lipophilicity ,
and permeability could originate from differences in pka between the stereochemical clusters .
determination of
pka for 18 by spectrophotometric titration indeed revealed a pka difference of 1 unit for the tertiary amine ,
with 14 being less basic and consequently
less soluble and more lipophilic than the more basic 58 ( table 2 ) .
this difference
is most significant from a medicinal chemistry perspective because
it determines the ionic state of the compounds at physiological ph
values .
the ionic state , in turn , will affect the cellular permeability ,
in both uptake from the intestine to blood and distribution from blood
into tissues .
a much smaller , but significant , difference ( 0.2
units ) for the pyridine group was also observed between the two stereochemical
clusters , but this does not influence compound properties at physiological
ph .
after identification of two sets of compounds with identical calculated
physicochemical properties and functional groups ( table 1 ) yet displaying vastly different in vitro properties , the
underlying cause was concluded to be stereochemistry . it was assumed that the two clusters had major differences in intramolecular
interactions and conformational preferences that led to the differences
in pka and in vitro properties .
the pka values reported here represent a thermodynamic
process in which the ammonium ion ( r3nh ) dissociates
to the free amine ( r3n : ) and a proton , a reaction that
is more endothermic for compounds with higher pka values .
each pka unit equates
to a free energy difference of 1.36 kcal / mol at 298 k as defined by
the henderson hasselbalch equation and the relationship between
the free energy difference and the equilibrium constant for the acid base
reaction ( cf . supporting information ) . to investigate this process ,
diastereomers 1 and 8 were selected as representatives for
the c8,c9-trans and c8,c9-cis stereochemical clusters , respectively .
first , molecular mechanics calculations with a continuum solvation
model ( mmffs / generalized born solvation )
were used to determine the difference in strain energy between the
neutral and protonated forms of 1 and 8 ,
respectively .
interestingly , the lowest energy conformations of the
neutral forms of amines 1 and 8 were found
to be rigid because of a strong intramolecular amide
however , the neutral
form of cis - isomer 8 had a strain energy 2.6 kcal / mol
higher than trans - isomer 1 ( table 3 ) .
for the more flexible ammonium ion forms , 8 was also
higher in energy than 1 but only by 0.4 kcal / mol .
together
the differences between the isomeric reactants and products in deprotonation
of the ammonium ion add to a 2.2 kcal / mol difference , which would
be equivalent to 1 having a pka value 1.6 units lower than 8 , assuming that the free
energy difference is similar to the difference in strain energy .
quantum
mechanics calculations with continuum solvation ( b3lyp/6 - 31 g * with
the sm8 solvation model ) provided the
same conclusion but with a smaller energy difference between 1 and 8 .
the neutral cis - isomer 8 was 3.1 kcal / mol higher in free energy than the trans - isomer 1 , while the cation form of 8 was higher in energy
by 1.2 kcal / mol , leading to a total difference of 1.9 kcal / mol ( table 3 ) .
this difference between the calculated free energies
of the two stereoisomers would result in a theoretical difference
in pka of 1.4 units , somewhat more consistent
with the experimentally observed difference .
furthermore , use of a
thermodynamic cycle that separates the gas phase deprotonation from
solvation led to a predicted difference
of 1.1 pka units which , astonishingly ,
is identical to the experimental value ( cf . supporting
information for calculation ) .
the difference in deprotonation
energy between 1 and 8 was thus predicted
with excellent accuracy with the sm8
model ; however , all methods did not yield the same accuracy .
boltzmann finite
element method ( pbf ) , calculated a net difference in
free energy of solvation that was over 5 kcal / mol higher , leading
to a correspondingly larger predicted pka difference .
importantly , the difference in magnitude of the solvation
energy was in line with benchmark calculations that have shown sm8
to provide significantly better agreement with experimental solvation
energies .
all of the methods predicted
trans - isomer 1 to be lower in energy than cis - isomer 8 and that this is predominantly driven by the difference
in energy of the intramolecularly hydrogen bonded neutral amines .
independent of whether
molecular mechanics or quantum mechanics
was used , the minimum energy conformation of the neutral form in both
diastereomers had the same rigid core conformation containing an intramolecular
hydrogen bond ( figure 2 ) .
this constrained
conformation provides a model for explaining the large difference
in energy between the neutral species of 1 and 8 and also of the difference in pka .
newman projections along the c10c9 and c9c8 bonds
highlight the larger number of gauche interactions in cis - isomer 8 versus trans - isomer 1 .
the energy difference
between the protonated forms is lower because of the loss of the intramolecular
hydrogen bond allowing for more conformational freedom for both compounds .
comparison
of the neutral state of diastereomers 1 and 8 showing newman projections looking down the c10c9
bond ( left ) and the c9c8 bond ( center ) with gauche interactions
highlighted with red arrows .
the lowest energy conformations found
by quantum mechanics ( b3lyp/6 - 31 g * ) and molecular mechanics ( mmffs
force field , gb solvation ) are shown in color .
the results from the conformational calculations of compounds 1 and 8 were further investigated by nmr spectroscopy ,
with particular emphasis on the predicted intramolecular hydrogen
bond .
as 1 had a low solubility in aqueous solution ,
dmso - d6 was used as a surrogate for a
polar environment whereas cdcl3 was used to mimic the lipid
environment of a cell membrane .
significant downfield shifts were
displayed by n28-h of trans - isomer 1 , compared to cis - isomer 8 , both in dmso - d6 and in cdcl3 ( figure 3a ) .
for 1 , the
chemical shift of n28-h was almost identical in both solvents , whereas
a significant upfield shift was found for 8 in cdcl3 .
the lack of solvent dependence of the shift of n28-h in 1 , in combination with the downfield shift relative to 8 , suggests that n28-h in 1 is involved in an
intramolecular hydrogen bond in both solvents .
in contrast , the solvent dependence found for 8 indicates
that n28-h forms an intermolecular hydrogen bond to solvent in dmso .
in addition , the chemical shift of n28-h of compound 8 in dmso - d6 has a greater temperature
dependence than in compound 1 ( supporting
information spectrum si 16 ) , providing further support
for the presence of an intramolecular hydrogen bond in 1 but not in 8 .
( a ) overlays of h nmr spectra of 1 ( c8,c9-trans ,
red and green ) and 8 ( c8,c9-cis , blue and violet ) in
dmso - d6 and cdcl3 , respectively .
the resonance of n28-h in 1 and 8 is marked
with red and blue ovals in the overlays .
( b ) parts of the roesy spectra
of 1 and 8 recorded in dmso - d6 showing crosspeaks from n28-h .
roesy crosspeaks across
the eight - membered hydrogen - bonded ring are marked with red ovals
in the spectrum of 1 .
the crosspeak resulting from the coupling of n28-h and n15 is marked
with a red circle . to obtain information
on intramolecular distances within 1 and 8 ,
2d - roesy experiments were performed .
for trans - isomer 1 , several distinct rotating frame overhauser
effect ( roe ) peaks support the presence of a hydrogen bond between
n28-h and n15 .
thus , strong roe crosspeaks are observed between n28-h
and c19,23-h , c8-h and c16-h3 , revealing that n28-h
is in proximity to the tertiary amine region of 1 ( figure 3b ) .
these roes are not observed for the cis - isomer 8 , which only displays one strong roe correlation from n28-h
to the adjacent c36,32-h .
finally , a correlation between n28-h and
n15 was observed in a natural abundance h
n heteronuclear multiple bond correlation ( hmbc ) spectrum
of 1 ( figure 3c ) but could not
be detected for 8 .
this through bond scalar coupling
definitively proves the existence of a hydrogen bond between these
atoms and also indicates that it has a high stability .
thus , chemical shift differences , including
solvent and temperature dependencies , together with distance information
from the roesy experiments and finally information from h n hmbc spectroscopy all verified the presence
of an intramolecular hydrogen bond in compound 1 but
not in 8 .
as dmso - d6 , which
can not act as a hydrogen bond donor , was used in the nmr studies ,
it could be argued that the intramolecular hydrogen bond may not be
formed in aqueous solutions .
however , the intramolecular hydrogen
bond is strong in dmso - d6 as revealed
by the finding that it exists also at temperatures around 338 k ( figure si 16 ) and by the fact that it is
detected as a cross peak in the h
as the formation
of an intramoleccular hydrogen bond is also in line with the calculations
and experimental findings , it is likely that it is also formed in
aqueous solutions of trans - c8,c9 stereoisomers 14 .
the presence of an intramolecular hydrogen bond in
trans - isomers 14 , and its absence
in cis - isomers 58 , thus provides
a rationale for the
difference in pka of the tertiary amine
in the two sets of stereoisomers .
the pka difference also explains the influence of ph on cell permeability
in the caco-2 assay ( cf .
the degree of intramolecular
hydrogen bonding and thus the cell permeability of trans - isomers 14 were not measurably influenced by
a change in ph from 6.5 to 7.4 on the apical side of the cell monolayer .
on the other hand , cis - stereoisomers 58 , which have pka 7.1 , will become
increasingly deprotonated at higher ph , leading to an increased likelihood
of intramolecular hydrogen bonding which in turn results in a higher
cell permeability . in a final effort to verify the influence of intramolecular
hydrogen bonding on the properties of the two sets of stereoisomers ,
n - methylated derivatives of 1 and 8 that
are unable to form an intramolecular hydrogen bond were synthesized
( cf . supporting information ) .
as could
be expected , prevention of intramolecular hydrogen bonding gave an
n - methylated derivative of 1 that had a lipophilicity
and cell permeability within the ranges observed for the non - hydrogen - bonded
stereoisomers 58 ( figure si 1 , tables si 1 and si 4 ) .
the n - methylated
derivative of 8 retained a lipophilicity and cell permeability
close to that of 8 , also in line with expectations .
in summary , profiling of the complete matrix of stereoisomeric t. cruzi inhibitors 18 unexpectedly revealed a striking influence of stereochemistry on
solubility , lipophilicity , and cell permeability .
this effect on compound
properties was traced to the relative stereochemistry at the two adjacent
stereocenters at c8 and c9 in the eight - membered rings of 18 . for stereoisomers 14 , which had a trans - c8,c9 relationship ,
an intramolecular
hydrogen bond was favored that reduced the basicity of the tertiary
amine of the inhibitors while simultaneously shielding polarity from
the surrounding environment . as a consequence ,
14 were more lipophilic , less soluble , and had higher cell
permeabilities than cis - c8,c9 stereoisomers 58 , for which an intramolecular hydrogen bond was less favorable .
in comparison ,
limited profiling of other dos compounds that lacked
the opportunity of forming an intramolecular hydrogen bond showed
statistically insignificant variation between stereoisomers with regard
to their lipophilicity , solubility , and cell permeability ( figure si 2 ) .
another unexpected finding
was that the intramolecular hydrogen bond that influences the properties
of 14 came via formation of an eight - membered
ring .
in contrast , the majority of intramolecular hydrogen bonds found
in a recent exhaustive analysis of crystal structure databases involve
formation of five- or six - membered rings .
our observations emphasize the importance of preparing and screening
pure stereoisomers in chemical probe or drug discovery projects , since
their physicochemical as well as pharmacokinetic and pharmacodynamic
properties may be significantly different . the results obtained
for the stereoisomeric t. cruzi inhibitors point
to the opportunity that intramolecular hydrogen
bonding can be used to hide hydrogen bond donors and
adjust pka in design of druglike compounds
with properties at or beyond the ro5 .
they also suggest that not only
thermodynamically favored five- and six - membered rings but also intramolecular hydrogen bonding leading
to formation of larger rings may be used in optimization of compound
properties .
it can be assumed that opportunities to adjust physicochemical
properties , and subsequently cell permeability and oral bioavailability ,
will be of increasing importance as compound properties deviate further
and further beyond the ro5 .
this is supported by the fact that intramolecular
hydrogen bonding confers cell permeability and oral bioavailability
to cyclosporin a , a cyclic undecapeptide , with
properties far outside of the ro5 .
as revealed in this work and suggested
by others , conformational calculations
may be used for prediction of intramolecular hydrogen bonding , and
they may therefore have value as prospective tools for design and
optimization of bro5 compounds .
computed log poct tol values , i.e. , differences in
log p determined for partitioning between water
and octanol or toluene , respectively , have also been suggested for
prediction of intramolecular hydrogen bonding .
in addition , a recent analysis of crystal structure databases gave a list of intramolecular hydrogen
bonding motifs for five- to seven - membered hydrogen - bonded rings that
can also be deployed in compound design or optimization .
modulation
of challenging targets with extended binding sites requires
compound classes that reach into chemical property space near the
limit of what is acceptable for cell permeability and oral bioavailability , i.e. , into bro5 space .
macrocycles constitute
one example of compounds that predominantly reside in bro5 chemical
space and that also have demonstrated success in modulation of challenging
targets .
a recent comprehensive investigation
of macrocyclic drugs and clinical candidates revealed that a significant
number that are orally bioavailable had molecular weights , lipophilicities ,
and polar surface areas that were higher than for traditional oral
small molecule drugs .
however , it was
discovered that macrocycles , just as small molecule drugs , may have
no more than five hydrogen bond donors to allow for oral administration .
this observation , in combination with the findings
reported herein , further emphasizes that masking of hydrogen bond
donors by logical incorporation of intramolecular hydrogen bonds may
be of particular value in efforts to improve cell permeability and
oral bioavailability of compounds at the border of , or beyond , ro5
chemical space .
solubility was determined in phosphate buffered
saline ( pbs ) , ph 7.4 , containing 1% dmso .
each compound was prepared
at 100 mm by diluting 5 l of a 10 mm dmso stock in triplicate
with 495 l of both 100% dmso and pbs with 1% dmso .
compounds
were allowed to equilibrate at room temperature with a 750 rpm vortex
shake for 18 h. stirstix were included in each preparation to lessen
compound aggregation .
after equilibration , samples were analyzed by
uplc ms ( waters , milford , ma ) with compounds detected by sir
detection on a single quadrupole mass spectrometer .
the dmso samples
were used to create a two - point calibration curve to which the response
in pbs was fitted . the
method for measurement
of log d
was based on the traditional shake
flask technique , using uplc with quantitative mass spectrometry ( ms )
to measure the relative octanol and aqueous concentrations .
1-octanol
( hplc grade , 99% , sigma - aldrich ) and a 10 mm phosphate buffer
[ na2hpo42h2o ( p.a .
grade , merck )
and nah2po4h2o ( p.a . grade ,
merck ) ] were used .
equal parts of buffer and 1-octanol were vigorously
mixed in a separation funnel three times ( at least 15 min between
each mixing ) to saturate the solutions .
the mixture was left overnight
to separate the upper octanol phase from the lower buffer phase before
being used in the experiments .
compounds were assayed in pools of
eight , and four dilutions of buffer and octanol samples were analyzed
and evaluated for log d calculation .
all liquid
transfers were performed with a beckman biomek fx robot , and samples
were analyzed on a fast - scanning triple quadropole mass spectrometer
( waters micromass tqd with masslynx 4.1 ) coupled to a waters acquity
ultra performance lc using a acquity uplc hss t3 1.8 m , 2.1
mm 50 mm or acquity uplc beh c18 1.7 m , 2.1 mm
50 mm column .
transepithelial
transport of the
compounds through a caco-2 monolayer was determined in an automated
fashion using a tecan freedom evo 200 equipped with a te - mo 96 and
a teer station .
caco-2 cells were grown in dmem supplemented with
10% fcs for 1519 days on costar 24-well cell culture cluster
plates ( polycarbonate membrane , 0.4 m pore size ) .
chamber volumes
were 288 and 950 l on the apical and basolateral sides of the
cell monolayers , respectively , and all incubations were performed
with prewarmed buffers in a shaking incubator at 480 rpm and 37 c .
prior to assay , cells were washed with hbss supplemented with 25 mm
hepes ( hbss - hepes ) , ph 7.4 , to remove the culture medium .
after 15
min equilibration time the transepithelial electrical resistance ( teer )
was determined to assess acceptance of the cell plates into the assay .
a second measurement and a lucifer yellow leakage determination was
carried out after performing all the transport experiments to monitor
integrity of the cell monolayers throughout the study .
permeability
in the absorptive direction ( a b , apical - to - basolateral ) was
studied over 120 min at 10 m test compound .
the compound solutions
were freshly prepared from dmso stock solutions diluted into hbss
supplemented with 25 mm mes , ph 6.5 , or into hbss - hepes , ph 7.4 ; the
final solvent concentration was always 1% .
samples from the donor
side ( 2 l ) were drawn immediately after addition of test compound
and after 45 and 120 min .
the donor samples were diluted 1:100 with
198 l in hbss . from the receiver compartment
an amount of 200 l
is withdrawn after 45 and 120 min and replaced with fresh hbss - hepes ,
ph 7.4 . upon completion of the study all samples were quenched with
67 l of acetonitrile and analyzed subsequently using uplc / ms / ms
( see above ) .
the permeability was determined as the appearance rate
of compound on the receiver side , in relation to donor concentration ,
according to the following equation : where dq/[(dt)(t ) ] is the slope of the permeation profile across
the caco-2 cell monolayers , a is the surface area
of the transwell insert ( 0.33 cm ) , and d is the concentration on the donor side .
following the permeability
experiments , recovery from the donor and receiver compartments was
calculated from the following equation : where d0 and dend are the donor sample concentrations at the
beginning and last time points , respectively , vd is the donor side volume ( 0.288 ml for a b and 0.95
ml for b a ) , rend is the receiver
sample concentration at the last time point , and vr is the receiver volume ( 0.95 ml for a b and 0.285
ml for b a ) .
all measurements were performed in duplicate ,
and only minor standard
deviations ( ( 0.081.14 ) 10 cm / s )
and on average moderate to good mass recovery values ( 82% ) were observed .
for the caco abba measurements the
cells were grown as described above and the same robotic system ( tecan
freedom evo 200 equipped with a te - mo 96 and a teer station ) was used .
permeabilities were determined in both a b and b a ( basolateral - to - apical )
directions , and identical buffers , hbss - hepes , ph7.4 , were used on
both sides of the cell monolayer , irrespective of transport direction .
the test concentration was again 10 m for each test compound ,
and incubations were performed in duplicate . during incubation
the
transwell plates were placed in a shaking incubator at 480 rpm and
37 c .
b direction was at time points
0 and 60 min from the donor compartment ( a , 2 l , 1:100 dilution
in hbss ) and 200 l from the receiver side ( b ) after 60 min .
sampling in the b a direction was at time points 0 and 30 min
from the donor compartment ( b , 1 l , 1:100 dilution in hbss )
and 100 l from the receiver side ( a ) after 30 min .
permeabilities
were calculated as described above , and the efflux ratio was determined
from the permeability in b a and a b directions.where papp(b a )
indicates the apparent permeability coefficient in the basolateral
to apical direction and where papp(a b )
indicates the apparent permeability coefficient in the apical to basolateral
direction .
the pka values of the compounds were
determined with a glpka
instrument , equipped with a d - pas ( dip probe absorption spectroscopy )
lamp from sirius analytical ltd . a 10 mm standard dmso solution of
each compound
was made , 25 l of which was added to
25 l of phosphate buffer .
the phosphate buffer was added because
the amount of sample used is not enough to act as its own buffering
system while performing the titration .
the glpka instrument then added
a predetermined volume of ionic - strength - adjusted ( isa ) water ( 1.5
ml ) .
a ph - metric titration from low to high ph was performed . during
the titration ,
the glpka instrument collected a uv vis spectrum
by using the d - pas technique to establish a titration curve .
the electrode
was calibrated using a blank titration from ph 1.8 to ph 12.0 before
every individual determination .
precipitation
was continuously monitored at 500 nm , which was apparent for the more
insoluble analogues .
the calculated log p ( clogp ) was generated
using the acd / labs physchem batch
predictor with the shipped database .
conformations for the tertiary amine and the
ammonium conjugate acid were generated using the lowmodemd method
in moe 2012 , using the mmffs force field
and the generalized born solvation model .
these were then clustered using the conformer hierarchical
clustering using canvas , version 1.5 , with atomic rmsd of heavy atoms
plus oh and sh to yield 10 clusters .
the lowest energy
conformers within 2 kcal / mol , as well as the lowest energy conformer
in each of the clusters , were kept for optimization using quantum
mechanics in jaguar 8.1 .
the optimization
used a medium sized basis set ( 6 - 31 g * ) with the b3lyp hybrid density
functional method in conjunction with the poisson boltzmann
finite element method for solvent reaction field optimization
and aqueous solvation energy prediction .
the geometries and energy
ranking of the resulting conformers were similar for both methods .
the sm8 and pbf solvent models were used to calculate the free energy
of hydration for the gas - phase minimized geometries .
a bruker avance 600 mhz system equipped
with a 5 mm tci ( cryo ) probe or a bruker avance iii 500 mhz system
equipped with a 5 mm rt bbfo plus probe was used to analyze the compounds
in dmso - d6 ( sigma aldrich , 99.9% deuteration )
or cdcl3 ( sigma aldrich , 99.9% deuteration ) at 298 k. for
assignment typically 12 mg of substance was dissolved in 140
l of dmso - d6 and transferred to
a 2.5 mm bruker match tube .
h and c resonances
were assigned using standard 1d and 2d bruker pulse sequences ( topspin ,
version 2.1 ) .
h
hsqc , and c h hmbc experiments were performed to determine h , c connectivities .
h h roesy was used for intramolecular distance information ,
and an h
n hmbc experiment was
utilized to obtain indirect n chemical shift information
and connectivities .
h and c chemical shifts
were referenced relative to residual solvent signals set to 2.50 and
39.5 ppm ( dmso ) and to 7.27 and 77.0 ppm ( cdcl3 ) .
temperature dependence studies
were made on the same dmso - d6 samples
and on samples of similar concentration in cdcl3 .
Output:
| profiling
of eight stereoisomeric t. cruzi growth
inhibitors revealed vastly different in vitro properties such as solubility ,
lipophilicity , pka , and cell permeability
for two sets of four stereoisomers . using computational chemistry
and nmr spectroscopy , we identified the formation of an intramolecular
nhnr3 hydrogen bond in the set of stereoisomers
displaying lower solubility , higher lipophilicity , and higher cell
permeability .
the intramolecular hydrogen bond resulted in a significant
pka difference that accounts for the other
structure property relationships .
application of this knowledge
could be of particular value to maintain the delicate balance of size ,
solubility , and lipophilicity required for cell penetration and oral
administration for chemical probes or therapeutics with properties
at , or beyond , lipinski s rule of 5 . |
PubmedSumm118728 | ***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: they are usually luted with resin cements , which promote an increase in retention when compared to conventional cements , such as zinc phosphate [ 2 , 3 ] . however , this technique is very sensitive and the manufacturers protocol must be carefully followed in order to achieve successful restorations . to simplify the cementation technique ,
these cements are dual - curing , with the characteristic of self - adhesion to the tooth structure , which eliminates the need of adhesive systems .
studies have been developed to evaluate the influence of adhesive systems , resin cements , and curing modes on the retention of fiber posts [ 68 ] .
however , there have been few studies on the cement film thickness and its influence on the bond strength of these posts .
the use of prefabricated posts with a diameter that does not correspond to the size of the root canal preparation is common in dental practice . in some clinical situations , such as the presence of caries in the cervical third of a root canal , oval shaped roots , or canals that are larger in the cervical portion ,
an enlargement of the post space diameter is necessary to obtain a precise adaptation of the post to the canal , leading to excessive removal of tooth structure .
however , it has been speculated that the intimate contact produced by the drill and the fiber post may not provide enough space for the resin cement to provide its maximum strength .
therefore , the possibility of increasing the film thickness of the cement in order to increase the bond strength between resin cement and root dentin has been questioned .
the purpose of this in vitro study was to evaluate the influence of the cement film thickness on the bond strength of glass fiber posts in different portions of the root canal ( cervical , medium , and apical ) , cemented with a self - adhesive resin cement , using a push - out test .
the hypotheses tested were as follows : there was no difference between ( 1 ) the bond strength values and the three cement film thicknesses and ( 2 ) the bond strength values at the cervical , middle , and apical thirds of the root canals .
thirty single rooted human teeth , with a root length greater than 15 mm and without root curvature , were selected for this present study .
they were stored after extraction in distilled water at 37c and used within six months .
the teeth were transversally sectioned at the cementoenamel junction using a diamond blade ( diamond wafering blade 15 hc / buehler , lake bluff , il , usa ) in a cutting machine ( labcut 1010/extec corp . , enfield , ct , usa ) .
the roots were embedded in epoxy resin using plastic cylinders with a 17 mm diameter .
all roots were instrumented using the step - back technique and obturated using the lateral condensation technique with gutta - percha and the endodontic cement , sealer 26 ( dentsply maillefer ) .
after storage , the canals were enlarged with # 2 , # 3 , and # 4 gates - glidden burs , leaving 5 mm of gutta - percha at the apex .
the roots were randomly divided into three groups ( n = 10 ) , according to the whitepost dc system 's drills ( fgm , joinville , sc , brazil ) : ( g1 ) preparation of the canal with the # 2 drill ; ( g2 ) # 3 drill ; ( g3 ) # 4 drill .
cementation was performed using the dual - curing self - adhesive resin cement , relyx u100 in a clicker dispenser ( 3 m espe , st .
a small amount of powdered rhodamine b was incorporated into the cement during the mixing procedure to give the cement a pink color and allowing it to be easily distinguished from the fiber post and root canal dentin .
the amount of rhodamine b used was measured using the tip of a short needle to catch a few grains for one measure dosed by the clicker ( 197 mg ) .
all groups were cemented with the double - tapered translucent glass fiber post of the # 2 whitepost dc system .
the thickest end of the post has a diameter of 1.8 mm , while the thinnest end of the post has a diameter of 1.05 mm .
the posts were cleaned with 92.8% ethanol and silanized with relyx ceramic primer ( 3 m espe ) before cementation .
the cement was applied onto the post surface and injected into the root canal using a specific syringe with a tube and needle ( centrix system , dfl , rio de janeiro , rj , brazil ) .
light activation was performed at the top of the fiber post for 40 seconds with an irradiance of 950 mw / cm , as measured by a radiometer ( hilux ledmax curing light meter , sdi , bayswater , vic , australia ) .
the resin cement was covered with a glass ionomer cement ( ketac fil plus , 3 m espe ) .
after storage , the roots were transversally sectioned with a diamond blade ( diamond wafering blade 15 hc ) in a cutting machine ( labcut 1010 ) at a speed of 150 rotations per minute ( rpm ) .
six slices , with 1 0.10 mm thickness , were obtained , corresponding to the cervical , middle , and apical thirds , for a total of 2 slices per region .
the push - out bond strength test was performed with the universal testing machine , emic dl-200 mf ( emic / so jos dos pinhais , pr , brazil ) , using a cell load of 50 kg at a crosshead speed of 0.5 mm / min until post dislodgment .
the slices were positioned on a push - out jig immediately after the cutting procedures . due to the conical shape of the posts
the metallic end of the plunger , which measured 0.8 mm in diameter , was positioned to touch only the post , so as not to create tension in the surrounding dentin walls .
after the push - out test , the specimens were individually stored in a dry setting .
these values were obtained dividing the force to cause the failure in n for the adhesion area in mm .
considering its conical shape , the exact area of the post fragment was previously calculated using the following mathematical formula : (r + r)[h + ( r r)]0.5 , where r = radius of the cervical side of the post ( mm ) ; r = radius of the apical side of the post ( mm ) ; h = thickness of the slice ( mm ) .
the r and r dimensions were measured using images of the cervical and apical sides of the slices , captured before the mechanical test by the stereomicroscope , stereo discovery v8 , with 1.6x magnification and the integrated camera , axiocam icc1 ( carl zeiss micro imaging gmbh / jena , germany ) .
the scalings control tool of this software allowed the ability to obtain each pixel dimension in m , so the radii of the posts were obtained .
the thickness of the slices ( h ) was measured with the digital external micrometer ( digimess / so paulo , sp , brazil ) . in order to obtain the cement film thickness
, the images captured prior to the push - out test were again evaluated using the software , axiovision 4.8 .
tool was used to manually contour the perimeter of the perfectly round post or canals ( figure 1(a ) ) , and the outline spline
tool was used to contour the perimeter of oval or irregular canals ( figure 1(b ) ) .
the delimited contours of each image were converted into a new binary image with a white outline and black background , to be processed in the software , ks 400 8.0 ( carl zeiss ) . a macro routine ( sequence of commands from the software )
was developed to digitally process the binary images , to measure the cement film thickness of each specimen . in each image , 36 radius lines were traced from the center of the post , with 10-degree intervals , intercepting the perimeter of the post and the root canal ( figure 2(a ) ) , obtaining the intersection of the radius lines with the cement area ( figure 2(b ) ) .
the average of the 72 measurements ( cervical and apical ) was obtained . to determine the failure mode ,
new perpendicular and oblique images were captured after the mechanical testing from both sides of each slice using the stereomicroscope .
fracture modes were classified as adhesive between resin cement and dentin ( figure 3(a ) ) ; adhesive between resin cement and fiber post ( figure 3(b ) ) ; and mixed fractures ( figure 3(c ) ) .
nonparametric options to anova and post hoc multiple comparison tests were chosen due to departing from normality and heteroscedasticity in the data .
tables 1 and 2 show three analyses each : more general differences among groups ( horizontal comparison in the bottommost row of the table ) ; differences among groups for each third ( horizontal comparison ) ; and differences among thirds inside each group ( vertical comparison ) .
there were statistically significant differences in the cement film thickness among all groups ( p < 0.05 ) .
g3 ( 248.78 m ) presented statistically higher values of cement film thickness , followed by g2 ( 185.92 m ) and g1 ( 110.16 m ) ( table 1 ) .
it was also observed that the push - out bond strength was statistically influenced by the drill size of the whitepost ( wp ) system used on the preparation of the post space ( p < 0.05 ) .
g2 presented the highest bond strength values ( 14.62 5.15 mpa ) , followed by g1 ( 10.04 5.13 mpa ) and g3 ( 7.68 6.14 mpa ) . when comparing thirds , g2 showed statistically significant differences . in the apical third ( 18.37 4.13 mpa ) the values were higher than the middle third ( 15.10 3.60 mpa ) .
lower values were found in the cervical third ( 10.34 4.43 mpa ) for this group . for g1 higher values were found in the apical third ( 12.72 4.58 mpa ) . the cervical ( 7.67 4.92 mpa ) and middle ( 9.50 4.83 ) thirds presented statistically similar values .
g3 also presented higher values in the apical third ( 11.25 6.12 mpa ) , and the cervical ( 6.06 6.01 mpa ) and middle ( 5.92 5.00 mpa ) thirds presented statistically similar values ( table 2 ) .
g1 presented predominantly mixed failures ( 46% ) , while g2 presented adhesive failures between the post and cement ( 48% ) , and g3 presented adhesive failures between cement and dentin ( 71% ) ( table 3 ) .
the mechanical test used in the present study was the push - out test , which allows for the evaluation of the bond strengths in different regions of the root canal , with the results of the shear stress between the dentin / cement and cement / post being comparable to clinical conditions [ 4 , 11 , 12 ] . despite being a sensitive technique , the high standard deviation found in this study can be explained mainly due to the inherent characteristics of the root dentin , as the morphology , density , and orientation of the dentinal tubules , predominantly in the apical region [ 13 , 14 ] ; the root canal morphology and high c - factor ; presence of a smear layer ; difficult access of instruments and light , and presence of remnants of gutta - percha and endodontic cement . a factor that could be avoided in
the current study was the use of an endodontic cement without eugenol , sealer 26 ( dentsply maillefer ) .
some authors affirm that sealer 26 does not interfere with the bond strength of fiber posts cemented with self - adhesive cements .
the post used in this present study was a double - tapered glass fiber post that has an elastic modulus similar to the dentin , which may result in a more favorable fracture mode [ 16 , 18 , 19 ] .
additionally , it has a high fiber concentration per surface area , which may increase the fracture resistance of the posts . in order to cement the posts ,
the resin cement relyx u100 ( 3 m espe ) was used in this study . as
this cement is autoadhesive , acid etching prior to its application would be detrimental for the dentin bonding effectiveness , since it could promote an inadequate infiltration of the demineralized collagen mesh .
so , the pretreatment of the root dentin was performed exclusively with naocl , following the manufacturer 's instructions ( 3 m espe ) .
this technique favors the incorporation of air into the cement mix . in order to reduce the presence of air bubbles within the cement , a centrix syringe with a needle tip was used during the cementation procedure , and the absence of these voids in the majority of the specimens
some authors suggest that the presence of air bubbles in the structure of the resin cement may reduce the stress provided by the high c - factor .
however , the mechanical properties of the cement could be prejudiced , increasing the chances of adhesive failure . regarding the methodology used to measure the cement film thickness
, some methods can be found in the literature to measure the cement film thickness , as follows : average values obtained in 4 manual measurements using digitally processed images , values obtained with digitally processed images by subtracting the area of the post and root canal , and values obtained by subtracting the diameters of the post and bur [ 4 , 12 , 16 ] . in the current study , the analysis of the cement film thickness was made with 36 measurements on each side of the slice , with a total of 72 measurements , using a macro routine developed in the ks 400 software , which provided the ability to obtain a more precise average value , thereby simplifying the gathering of results by automation while standardizing the procedures .
the bond strength values among the groups were statistically different , with the lowest values found in g3 ( 7.68 6.14 mpa ) , which had the greatest cement film thickness ( 248.78 m ) .
g1 ( 10.04 5.13 mpa ) , with the thinnest cement film thickness ( 110.16 m ) , presented higher values than g3 ; however , those values were lower than g2 ( 14.62 5.15 mpa ) , which had an intermediate cement thickness ( 185.92 m ) . with these results ,
the first null hypothesis can be rejected , as there were differences among the groups .
some authors speculated that the intimate contact produced by drills and fiber posts systems with the same diameter may not provide enough space for the resin cement to develop its maximum strength .
additionally , it is known that the c - factor increases in root canals where there is a considerable thin cement film thickness .
some authors presented similar results , observing that the use of burs with a diameter slightly thicker than the one indicated by the manufacturer results in higher pull - out bond strength of fiber posts cemented in root canals with resin cement [ 9 , 12 ] . despite the similar results , the materials used in these studies were different from the ones used in this present study .
used cylindrical metallic posts ( parapost ) and autopolymerizing resin cement ( panavia 21 op ) .
used quartz fiber posts ( endo light - post ) and autopolymerizing resin cement ( panavia 21 op ) .
other studies did not observe significant differences in push - out bond strengths among the various cement film thickness tested [ 16 , 23 ] .
used the autopolymerizing resin cement , post cement hi - x , and perez et al . used the dual resin cement , duolink ( bisco ) . both studies used quartz fiber posts ( dt light - post )
one study showed that precisely fitted tapered glass fiber posts ( dentinpost er ) cemented with various cements , including the self - adhesive cement , relyx unicem , presented higher bond strengths . despite the similarity between the materials used in this present study , those specimens were subjected to thermocycling and the pull - out test , influencing the results . in the current study ,
the root canal section significantly influenced the bond strength , with higher values found in the apical third in all groups ( table 2 ) .
therefore , the second null hypothesis was also rejected , as there were differences among the thirds . bitter et al
. presented similar results , where the apical and middle thirds showed greater bond strength values .
however , cecchin et al . did not observe a difference in the bond strength values among the thirds .
other studies found different results , with a reduction on the bond strength values of the self - adhesive resin cements relyx u100 or unicem toward the apical third [ 15 , 26 ] .
some authors claim that the increase in bond strength is directly related to the increase of the density of the dentinal tubules [ 15 , 26 ] . a reduction of the bond strength toward the apical third
would be expected , considering that the density of the dentinal tubules is lower in this third when compared to the middle and cervical thirds . however , this was not observed in the current study , indicating that the bond strengths between fiber posts cemented with self - adhesive cements may be more related to the presence of solid dentin [ 27 , 28 ] .
g1 presented predominantly mixed failures , while g2 presented adhesive failures between the post and cement , and g3 presented adhesive failures between cement and dentin . some studies that used relyx u100 or unicem showed more failures between cement and dentin [ 11 , 29 , 30 ] .
it was not possible to draw a conclusion about the cause of the failures , since they were too diverse , which can indicate that the rhodamine b could have had an influence on the failure mode .
however , it has been demonstrated that the rhodamine b does not influence the bond strengths when used in low concentrations [ 32 , 33 ] , as used in the present study .
further studies are needed to evaluate thermal and mechanical aging while using more accurate methods to measure the cement film thickness . despite the important role of rhodamine b in the methodology of this study , the use of rhodamine b as a marker in adhesive cements
in addition , bur diameter should be considered for minimal removal of dentin structure to obtain sufficient bond strength of fiber posts cemented with self - adhesive resin cements . regarding the results of this present study
, it can be advised to prepare post spaces with a diameter slightly greater than the glass fiber post .
when considering the experimental conditions of the present study ( in vitro ) , it can be concluded thatthe three bur diameters tested significantly influenced the bond strength results .
higher values were obtained when using the # 3 bur associated with the # 2 fiber glass post from the whitepost dc system , indicating that the slight increase in the cement thickness allowed an increase in the values of shear bond strength in comparison with very thin ( # 2 bur ) or very thick ( # 4 bur ) cement films;the bond strength values were higher in the apical third of the root canal , when compared with the middle and cervical thirds .
higher values were obtained when using the # 3 bur associated with the # 2 fiber glass post from the whitepost dc system , indicating that the slight increase in the cement thickness allowed an increase in the values of shear bond strength in comparison with very thin ( # 2 bur ) or very thick ( # 4 bur ) cement films ; the bond strength values were higher in the apical third of the root canal , when compared with the middle and cervical thirds .
Output:
| the present study evaluated the influence of the cement film thickness on the push - out bond strength of glass fiber posts in the cervical , medium , and apical thirds of root canal spaces .
thirty roots were randomly divided into three groups , according to the fiber post system 's drills : ( g1 ) # 2 ; ( g2 ) # 3 ; ( g3 ) # 4 .
the posts were cemented using a self - adhesive cement , and a small amount of powdered rhodamine b was used as a stain .
images of both sides of each slice were obtained before and after the push - out test . to determine the cement thickness , a macro routine
was developed using the software ks 400 .
the data were analyzed statistically using kruskal - wallis and dunn 's test .
g2 ( 14.62 5.15 mpa ) showed statistically higher bond strength values than g1 ( 10.04 5.13 mpa ) and g3 ( 7.68 6.14 mpa ) .
all groups presented higher bond strength values in the apical third .
the bur diameter significantly influenced the results of the shear bond strength for the push - out test .
the slight increase in the cement thickness allowed an increase in the values of shear bond strength when compared to very thin or very thick cement films . |
PubmedSumm118729 | ***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: curves are congenital and rigid , larger than 80 at birth and progressing to more than 100 4 .
these lead to chronic pressure sores , impaired sitting balance , collapsing spine phenomena , decreased abdominal capacity , and reduced respiratory function 4 .
there is no consensus regarding the proper mode of correction in patients with mmc 5 .
to present the long - term results of a segmental spino - pelvic fixation method for correction of congenital thoracolumbar kyphotic deformities in patients with mmc using luque rods and neuroforaminal wires .
study design : retrospective case series ( all medical records of the children were reviewed ) .
thoracic level mmc ( t6t12 ) and congenital rigid kyphotic deformity all patients referred for surgical correction at one institution a patent ventriculoperitoneal shunt active skin or urinary tract infection inadequate nutritional status ( albumin levels within normal age correlated levels ) thirteen consecutive patients meeting study criteria all patients were paraplegic from mmc level down all patients had skin scarring from abrasions or lacerations on the apex of the deformity patients were placed on specialized silicon cushions and prepared for a posterior approach .
a posterior longitudinal incision was executed and dissection of the soft - tissue flap was kept as thick as possible .
the dural sac was released , ligated , cut , and removed at the level of the mmc .
fixation started four or five segments above the beginning of the deformity down to the sacrum using the galveston technique 1 ( fig 3 , figs 7,8a,8b,9,10 ) .
standard x - rays were performed every 6 to 8 weeks to evaluate : fusion rate fusion defined as connecting vertebrae in the lateral view and a bony mass on the sides of the bifid vertebrae uniting the two vertebrae in the anteroposterior view time to fusion defined as the first x - ray with evidence of fusion change in the cobb angle ( comparing preoperative with postoperative cobb angles ) functional outcomes using : katz independence in activity of daily living ( adl ) score 6 .
a scale of 06 points testing patient independence in bathing , dressing , toileting , transferring , continence , and feeding .
a patient gets 1 point for each activity he / she is unable to perform .
the higher the score , the lower the function . independence in adls suggested as a score of 0 to 1 point sitting position
assessed as either independent or needing hand - hold support descriptive statistics were performed including mean sd for continuous measures and frequency counts for categorical variables .
preoperative image of a child after being placed on the operating table ; note two silicon rolls lowering pressures from the chest .
average time to final follow - up was 120 months ( range , 20310 months ) . among the 13 subjects , 9 ( 69% ) were male .
the average age at time surgery was 9.2 years ( range , 4.517 years ) and average kyphosis was 108 ( range , 90130 ) ( table 1 ) .
mean time to fusion was 12 months ( range , 916 months ) ( fig 6 ) .
the mean postoperative kyphotic curve measurement was 22 ( range , 1530 ) ( fig 4 ) .
the katz adl 6 score improved by an average of 1.6 ( mean , 2 ; range , 03 : sd=0.8 ) points .
all patients achieved an erect , balanced sitting position allowing mobilization in wheelchairs and sitting in chairs without the need of hand support ( fig 5 ) .
correction of congenital kyphotic deformity in patients with mmc is challenging and has a high rate of complications .
the goal of surgery is to provide them with a stable , balanced , and fused spine allowing balanced sitting , free mobilization and proper nutrition 3 .
others have reported that the elimination of the need of an anterior approach reduces the morbidity of surgery 7,8 .
the correction affects not only the children but also their parents and caretakers , with an improvement in adls and a subjective improvement in social status and improved self - image 9 .
solid fusion was achieved in 9 patients ( 69% ) , with a mean time to fusion of 12 months .
the complication rate in the presented series was 38% , while in similar series it ranged 2889% ( table 2 ) 10,11,12,13,14,15 .
patients improved in their adls and were all independent at sitting after surgery . the tailor - made jacket worn by the patients
reduces the strain on the rods and adjacent soft tissues , thus decreasing persistent skin break down 16,17 .
compliance with the brace was high ; it was worn more than 90% of daytime .
strengths : the study evaluated consecutive patients with a long - term follow - up . a standardize adl score
limitations : this was a retrospective case series with a small number of cases and no comparison group . we can not state that this method of treatment is more effective or safer than others . for further discussion , see the web appendix at www.aospine.org/ebsj .
the long - term outcome of kyphectomy with long posterior segmental fixation provides for acceptable functional outcomes , a relatively low rate of manageable complications compared with other studies .
the main cause of complications in these patients is hardware related . in most cases , requiring the need of hardware removal , keeping the brace on , and treating infections can result in stable fibrous union and with a balanced sitter .
future studies are needed to compare this method with others to establish the evidence for safety and efficacy .
case series rightfully remain next to the bottom of the evidence hierarchy . however , they can have merit for exceptional conditions or as a basic fact - finding investigation , especially when conducted in truly sequential fashion with consistent care application and appropriate long - term follow - up . despite its limitation as case series ,
this article received favorable reviews for being interesting and commendable with excellent long - term follow - up of wound and hardware complications with a specific technique for a difficult clinical problem .
the katz functional outcome instrument was found to be applicable , relevant , and simple to use and a welcome expansion of the outcomes armamentarium .
the following limitations , which could not be resolved due to infrastructure and study design , were noted and could conceivably have enhanced the study further : methodology of patient identifications and records review was not elucidated .
the following complications common to this population were not discussed either because of incredible technique or the failure to document them : urinary tract infection hydrocephalus problems neurogenic pain or symptoms the only complications documented were related to hardware failure , nonunion , or wound complications . were any patients excluded from this case series or did every patient with myelomeningocele and kyphosis meet the criteria ?
an attempt at comparison to other treatment groups would have elevated the status of this study tremendously , for instance assessment of patients treated nonoperatively , or assessment of surgical technique other than neuroforaminal wires .
now the prevailing question on every surgeon 's mind after reading this article will be : how does this specific method of fixation compare to other options pedicle screws , iliac bolts , hooks , or unit rods ?
the comparisons with other articles are appreciated ; however an attempt to consolidate the variables looked at in those articles and an attempt to align them with the variables studied in this article more comprehensively would have been a welcome addition . in conclusion ,
the article of schroeder et al advances our knowledge base on this condition and refocuses our attention on the indication for which we operate , and raises the important question of relevance of high - tech implants to achieve optimal outcomes for specific conditions .
case series rightfully remain next to the bottom of the evidence hierarchy . however , they can have merit for exceptional conditions or as a basic fact - finding investigation , especially when conducted in truly sequential fashion with consistent care application and appropriate long - term follow - up . despite its limitation as case series ,
this article received favorable reviews for being interesting and commendable with excellent long - term follow - up of wound and hardware complications with a specific technique for a difficult clinical problem .
the katz functional outcome instrument was found to be applicable , relevant , and simple to use and a welcome expansion of the outcomes armamentarium .
the following limitations , which could not be resolved due to infrastructure and study design , were noted and could conceivably have enhanced the study further : methodology of patient identifications and records review was not elucidated .
the following complications common to this population were not discussed either because of incredible technique or the failure to document them : urinary tract infection hydrocephalus problems neurogenic pain or symptoms the only complications documented were related to hardware failure , nonunion , or wound complications . were any patients excluded from this case series or did every patient with myelomeningocele and kyphosis meet the criteria ?
an attempt at comparison to other treatment groups would have elevated the status of this study tremendously , for instance assessment of patients treated nonoperatively , or assessment of surgical technique other than neuroforaminal wires .
now the prevailing question on every surgeon 's mind after reading this article will be : how does this specific method of fixation compare to other options pedicle screws , iliac bolts , hooks , or unit rods ?
the comparisons with other articles are appreciated ; however an attempt to consolidate the variables looked at in those articles and an attempt to align them with the variables studied in this article more comprehensively would have been a welcome addition . in conclusion ,
the article of schroeder et al advances our knowledge base on this condition and refocuses our attention on the indication for which we operate , and raises the important question of relevance of high - tech implants to achieve optimal outcomes for specific conditions .
Output:
| study design : a retrospective case series of patients with myelomeningocele ( mmc ) who underwent kyphectomy and posterior segmental fixation using luque rods and 16-gauge wires.objective : to assess outcomes after posterior kyphectomy and segmental fixation for kyphosis in patients with mmc.methods : thirteen consecutive patients who underwent posterior kyphectomy for transforaminal fixation contiguous to everted lamina .
fusion rates , time to fusion , change in cobb angle , complications , and improvement in activities of daily living using the katz score were measured.results : average age at time of surgery was 9.2 ( range , 4.517 ) years .
average time to follow - up was 120 ( range , 20310 ) months .
solid fusion was achieved in 9 patients ( 69% ) with a mean time to fusion of 12 months .
the mean postoperative kyphotic curve was 22 with an average correction of 90. five patients ( 38% ) experienced a postoperative complication .
the mean improvement in activities of daily living score was 1.6 points and all patients achieved independent sitting balance.conclusion : segmental spino - pelvic fixation is a solid alternative mode of fixation in patients with mmc with congenital kyphosis .
patient selection , proper perioperative multidisciplinary assessment , and surgeons ' expertise are significant in the success of this complex surgery.methods evaluation and class of evidence ( coe)study design : prospective cohort retrospective cohort case control case seriesmethods patients at similar point in course of treatment follow - up 85% similarity of treatment protocols for patient groups patients followed - up long enough for outcomes to occur control for extraneous risk factorsoverall class of evidenceivthe definiton of the different classes of evidence is available on page 63 . |
PubmedSumm118730 | ***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 is caused by complex interactions between insulin resistance in the peripheral tissues and impaired insulin secretion by pancreatic -cells . there is a general consensus that the latter results from both impaired -cell function and decreased -cell mass .
the high activity of molecules , such as reactive oxygen species ( ros ) and clusters of reactive nitrogen species ( rns ) , could cause oxidative damage , leading to tissue injury .
the classical pathway of apoptosis includes the cell death receptor pathway ( extrinsic pathway ) and the mitochondrial death pathway ( intrinsic pathway ) .
recent studies have revealed that the endoplasmic reticulum ( er ) is an organelle that can sense various stresses and transmit apoptotic signals [ 1 , 2 ] .
one characteristic feature of -cells is a highly developed er , which arises from the large amounts of insulin secretion .
abnormal oxidation and impaired protein folding can lead to endoplasmic reticulum stress ( ers ) .
glucagon - like peptide 1 ( glp-1 ) , which is secreted in a glucose - dependent manner , is involved in glucose - stimulated insulin secretion , insulin biosynthesis , inhibition of glucagon secretion and gastric emptying , and the inhibition of food intake .
glp-1 also inhibits -cell apoptosis and promotes -cell proliferation in animals and cultured cells in vitro .
the chronic administration of glp-1 also promotes insulin synthesis , -cell proliferation , and -cell neogenesis [ 46 ] .
an important locus for the regulation of glp-1 biological activity is the n - terminal of the peptide via dipeptidyl peptidase iv ( dpp-4)-mediated cleavage at the position 2 alanine .
the half - life of active glp-1 in the circulation is only approximately 2 min , which limits its clinical value .
therefore , it has a longer half - life than glp-1 and would be more suitable as a therapeutic agent . at present
, the action of glp-1 on the ers signaling pathway in pancreatic cells has not been fully explained .
. demonstrated that glp-1 receptor signaling directly modulates the er stress response , leading to the promotion of -cell adaptation and survival .
. found that exendin-4 inhibits apoptosis elicited by il-1 , which highlights the importance of glp-1 mimetics as new potent inhibitors of cytokine - induced jnk signaling .
tert - butyl hydroperoxide ( t - bhp ) is an organic lipid hydroperoxide analog , which is commonly used as a pro - oxidant to evaluate mechanisms involving oxidative stress in cells and tissues . in this study
furthermore , we investigated whether exendin-4 could protect cells from t - bhp - induced apoptosis .
moreover , we explored the antiapoptotic molecular mechanisms of exendin-4 , including an assessment of the ers and jnk signaling pathways , in t - bhp - treated cells .
exendin-4 , t - bhp , dulbecco 's modified eagle 's medium ( dmem ) , hanks ' balanced salt solution ( hbss ) , and fetal bovine serum ( fbs ) were obtained from gibco ( grand island , ny , usa ) .
primary antibodies , including rabbit polyclonal antibodies to sheep p - ire1 and ire-1 , were purchased from santa cruz biotechnology ( santa cruz , ca , usa ) .
rabbit polyclonal antibodies to sheep nh2-terminal kinase ( jnk ) , p - jnk , c - jun , p - c - jun , caspase-3 were purchased from cell signaling ( beverly , ma , usa ) . the jnk inhibitor , sp600125 ,
hoechst 33342/pi , caspase-3 activity assay kits , and the annexin v - fitc apoptosis kit were purchased from sigma - aldrich ( st . louis , mo , usa ) . the western blot chemiluminescent detection system ( lumiglo system )
the pancreatic min6 -cell line was a gift from the institute of endocrinology of ruijin hospital , which is affiliated with shanghai 2nd medical university ( shanghai , china ) .
min6 cells were maintained in dmem supplemented with 15% fbs , 100 units / ml penicillin , and 100 g / ml streptomycin and were kept at 37c in humidified air with 5% co2 .
cells were double - stained with hoechst 33342 and propidium iodide ( pi ) to distinguish apoptotic cells from necrotic cells .
cells were treated with t - bhp ( 25 m ) with or without exendin-4 ( 100 nm ) for the indicated time , washed with pbs ( ph 7.4 ) , and then stained with hoechst 33342 ( 10 g / ml ) and pi ( 10 g / ml ) for 5 min at room temperature .
one hundred cells were selected at three independent times and counted under a fluorescence microscope , and the rate of apoptosis was then calculated .
annexin v - fitc binding and pi staining were performed according to the manufacturer 's protocol and then analyzed by flow cytometry ( facscan , becton dickinson ) .
apoptotic cells were defined as the population that were pi negative ( indicating an intact plasma membrane ) and annexin v - fitc positive .
briefly treated cells were washed once with ice - cold pbs and assayed for caspase-3 activity using a colorimetric assay .
cleavage of ac - devd - pna substrate by caspase-3 releases pna , which was quantified spectrophotometrically at 405 nm using an elisa reader .
the treated cells were rinsed with ice - cold pbs and then incubated with ripa lysis buffer containing 50 mm tris - hcl ( ph 7.4 ) , 150 mm nacl , 1% triton - x 100 , 1 mm edta , 1 mm naf , 1 mm na3vo4 , 0.1% sds , 0.5% ( w / v ) sodium deoxycholate , 1 mm phenylmethanesulfonylfluoride ( pmsf ) , 10 g / ml aprotinin , 1 g / ml leupeptin , and 1 g / ml pepstatin for 20 min .
the cell lysates were then centrifuged at 12,000 g for 10 min , and the protein concentrations were determined using the bradford method . total cell protein ( 50 g )
was separated by 8% or 12% sodium dodecyl sulfate - polyacrylamide gel electrophoresis ( sds - page ) and transferred to pvdf membranes .
the membranes were incubated with the following appropriate primary antibodies : p - ire1 ( 1 : 1,000 ) , ire-1 ( 1 : 1,000 ) , jnk ( 1 : 1,000 ) , p - jnk ( 1 : 1000 ) , c - jun ( 1 : 1,000 ) , p - c - jun ( 1 : 1,000 ) , caspase-3 ( 1 : 1,000 ) .
data were analyzed by sigmastat 3.5 software and shown by the mean standard deviation ( sd ) of at least three independent experiments .
statistical differences between values were determined by student 's t - test or anova followed by tukey 's post hoc test .
the treatment of -cells with 25 mol / l t - bhp produced the maximal apoptotic response after 1 h as evidenced by results of the hoechst / pi and annexin v - fitc / pi assays ( data not shown ) .
cells treated with 25 mol / l t - bhp for 1 h clearly exhibited staining that was indicative of apoptosis ( bright blue particles ) ( figure 1(a)(b ) ) .
interestingly , exendin-4 treatment markedly inhibited the apoptotic bright blue particle formation in min6 cells ( figure 1(a)(d ) ) .
an annexin v - fitc / pi quantification assay demonstrated that t - bhp - induced min6 cell death was mediated by apoptosis ( figure 1(b)(b ) ) and that exendin-4 protected min6 cells from t - bhp - induced apoptosis ( figure 1(b)(d ) ) .
the inhibitory effect of exendin-4 was 77.6% ( p < 0.001 ) , whereas jnk inhibitor produced a 72.5% ( p < 0.001 ) reduction in the level of apoptosis induced by t - bhp ( figure 1(b)(e ) ) , which suggested that jnk signaling is involved in this process .
as shown in figures 2(a ) and 2(b ) , exposure of min6 cells to 25 mol / l t - bhp for 1 h resulted in approximate 2.3-fold figure 2(a ) and 7.5-fold figure 2(b ) ( p < 0.001 ) increases in activity of the prototypic apoptotic marker caspase-3 .
pretreatment of cells with exendin-4 reduced caspase-3 activity levels to 44.7% figure 2(a ) and 72.8% figure 2(b ) lower than that observed in the group treated with t - bhp alone ( p < 0.001 ) .
these results suggest that exendin-4 can attenuate t - bhp - induced apoptotic death by inhibiting the activation of caspase-3 in cells and that jnk signaling is involved .
western blot analysis showed that t - bhp increases ire1 phosphorylation by 2.6-fold ( p < 0.001 ) relative to the control group ( figure 3 ) .
pretreatment of cells with exendin-4 reduced the t - bhp - induced increase in ire phosphorylation by 58.7% ( p < 0.001 ) compared to the t - bhp alone group .
these results indicated that ers is probably required for the apoptotic events mediated by t - bhp and that jnk signaling is involved .
it is well known that the accumulation of proteins in the lumen of the er initiates a stress response known as the unfolded protein response ( upr)/endoplasmic reticulum overload response ( eor ) .
further experiments showed that t - bhp increases jnk phosphorylation by 1.9-fold ( p < 0.001 ) ( figure 4(a ) ) and c - jun phosphorylation by 1.7-fold ( p < 0.001 ) ( figure 4(b ) ) . pretreatment of cells with exendin-4 reduced the t - bhp - induced increase in jnk phosphorylation by 50.4% ( p < 0.001 ) ( figure 4(a ) ) and reduced the t - bhp - induced increase in c - jun by 84.9% ( p < 0.001 ) ( figure 4(b ) ) .
these results suggest that exendin-4 attenuates t - bhp - induced apoptotic death by modulating jnk - c - jun signaling in cells .
in the present study , we investigated the effects of exendin-4 on t - bhp - induced apoptosis .
we demonstrated that exendin-4 protects pancreatic cells from t - bhp - induced apoptotic death via ire1-jnk - caspase-3 signaling , which suggests the probable involvement of er stress in apoptosis .
type 2 diabetes is associated with a gradual loss of insulin secretion and a progressive reduction in -cell mass .
insulin resistance produces a sustained increase in demand for insulin , and , over time , the cells are unable to sustain the augmented levels of insulin biosynthesis and secretion .
the er has several important functions , including posttranslational modification , folding , and assembly of newly synthesized secretory proteins , and it also acts as a cellular calcium store .
ers is conducive to the maintenance of the normal function of cells and their survival ; however , prolonged ers can induce cell apoptosis .
therefore , -cell apoptosis induced by chronic ers is important in type 2 diabetes [ 11 , 12 ] . in our previous studies
, we demonstrated that min6 cell viability , when treated with t - bhp , was reduced in a dose - dependent manner .
we also found that continuous exposure to t - bhp induced oxidative damage in min6 cells .
the present study suggests that t - bhp treatment leads to the activation of death effector caspases , such as caspase-3 , resulting in nuclear fragmentation and apoptosis ( figures 1 and 2 ) .
further , t - bhp might trigger apoptosis in cells via ers signaling pathways ( figure 3 ) .
a small fragment of the x - box binding protein 1 ( xbp1 ) mrna is spliced out by the active form of ire1 to produce the active form of xbp1 .
this is supported by the observation that the stress effect caused by ire is mediated no later than the role of pek - related endoplasmic reticulum eukaryotic initiation factor 2 kinase ( perk ) and activating transcription factor 6 ( atf6 ) .
however , in response to ers , ire1 has been found to recruit the adaptor protein , tnf receptor - associated factor 2 ( traf2 ) , to the er membrane .
the ire1/traf2 complex then recruits apoptosis signal regulating kinase 1 ( ask1 ) , causing activation of ask1 and the downstream mitogen - activated protein kinase family ( mapks ) cascades , which leads to cell death
once activated , jnk is translocated from the cytoplasm to the nucleus , which in turn induces phosphorylation of its target transcription factor c - jun .
the er stress - mediated apoptosis pathway finally activates the mitochondrial death pathway , leading to caspase-3 activation .
therefore , the mitochondrial death pathway plays a role in synthesis and amplification in this pathway . in the present study
, we observed that the jnk inhibitor , sp600125 , can inhibit the activity of caspase-3 ( figure 2 ) ; t - bhp increased jnk phosphorylation by 1.9-fold ( p
< 0.001 ) ( figure 4(a ) ) and c - jun phosphorylation by 1.7-fold ( p < 0.001 ) ( figure 4(b ) ) , suggesting that the jnk signaling pathway is involved in the oxidative damage - induced apoptosis pathway .
pandey and rizvi found that when ins-1 cells were incubated with exendin-4 in the presence or absence of il-1 , glp-1 functioned as a potential inhibitor of the jnk signaling pathway to protect cells through the activation of drug induced apoptosis .
therefore , glp-1 receptor agonists have potentially important applications in the treatment of diabetes . in our present study
, we also found that exendin-4 inhibited t - bhp - induced -cell apoptosis by 77.6% ( p < 0.001 ) ( figure 1(b)(d ) ) .
pretreatment of cells with exendin-4 reduced the t - bhp - induced increase in jnk phosphorylation by 50.4% ( p < 0.001 ) ( figure 4(a ) ) and reduced the t - bhp - induced increase in c - jun by 84.9% ( p
these effects were similar to those observed following pretreatment with the jnk inhibitor , sp600125 , suggesting that exendin-4 attenuates t - bhp - induced apoptotic death by modulating jnk - c - jun signaling in cells .
the glp-1 receptor agonist , exendin-4 , protects islet cells by reducing the level of ers .
exendin-4 protects cells against free fatty acids via the induction of the er chaperone bip and the antiapoptotic protein junb , which mediate -cell survival under lipotoxic conditions .
we show that a certain degree of oxidative injury produces obvious ers and that the intracytoplasmic domain of the er transmembrane protein , ire1 , undergoes self - dimerization and phosphorylation - induced activation .
ire1 activation may promote apoptosis , and exendin-4 can inhibit the activation of ire1 to reduce the ers response , thereby protecting pancreatic cells . in recent years , the protective mechanisms of glp-1 have been elucidated .
. showed that regulation of -cell numbers and functions by glp-1 depends on the camp / protein kinase a - mediated induction of igf-1r expression and the increased activity of an igf-2/igf-1r autocrine loop .
klinger et al . demonstrated that the camp / protein kinase a / creb and mapk / erk1/2 pathways can additively control -cell proliferation , whereas aikin et al
. demonstrated that pi3k / akt suppresses the jnk pathway in islets and that this crosstalk represents an important antiapoptotic consequence of pi3k / akt activation .
. found that glp-1 suppresses p38 mapk and jnk via akt - mediated changes in the phosphorylation state of the apoptosis signal - regulating kinase 1 in ins-1 cells and human islets , which results in the inhibition of its activity .
thus , a variety of interactions appear to be involved in the glp-1 protection of pancreatic cells against er stress , such as chop , bip , grp78 , xbp-1 , ask1 , p - elf2 and ap1 , amongst others , which remain to be investigated .
the present study has demonstrated that exendin-4 has a protective effect against t - bhp - mediated -cell apoptosis through the inhibition of er stress .
we have shown that ire1-jnk - c - jun - caspase-3 pathways are involved . however ,
this study has only focused on one aspect of the er stress response . future studies will aim to identify additional downstream events that are regulated during persistent er stress .
Output:
| objectives . this study aimed to explore the effect of exendin-4 on t
- bhp - induced apoptosis in pancreatic cells and the mechanism of action .
methods .
murine min6 pancreatic cells were treated with exendin-4 in the presence or absence of tert - butyl hydroperoxide ( t - bhp ) .
cell survival was assessed by mtt staining .
the percentage of apoptotic cells was determined by fluorescence microscopy analysis after hoechst / pi staining and flow cytometric assay after annexin v - fitc / pi staining .
the activity of caspase-3 was determined using a caspase-3 activity kit .
expression of p - ire1 , ire1 , c - jun n - terminal kinase ( jnk ) , p - jnk , c - jun , and p - c - jun was detected by western blotting . results .
exendin-4 was found to inhibit t - bhp - induced apoptosis in pancreatic -cells by downregulating caspase-3 activity .
exendin-4 also inhibited the endoplasmic reticulum transmembrane protein ire1 , the apoptosis - related signaling molecule jnk , and c - jun activation .
conclusions .
our findings suggest that exendin-4 ultimately reduces t - bhp - induced -cell apoptosis .
ire1-jnk - c - jun signaling is involved in the exendin-4-mediated modulation of -cell apoptosis . |
PubmedSumm118731 | ***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: adults with childhood - onset type 1 diabetes are at increased risk for premature cardiovascular disease ( cvd ) morbidity and mortality compared with the general population ( 1 ) .
the antecedents of cvd begin in childhood ( 2 ) , and early or preclinical atherosclerosis can be detected as intima - media thickening in the artery wall ( 3 ) .
carotid intima - media thickness ( imt ) is an established marker of atherosclerosis because of its associations with cvd risk factors ( 4,5 ) and cvd outcomes , such as myocardial infarction and stroke in adults ( 6,7 ) .
prior work , including data from our study , has shown that youth with type 1 diabetes have higher carotid imt than control subjects ( 813 ) . in cross - sectional studies ,
risk factors associated with higher carotid imt include younger age at diabetes onset , male sex , adiposity , higher blood pressure ( bp ) and hemoglobin a1c ( hba1c ) , and lower vitamin c levels ( 8,9,11 ) .
only one study has evaluated cvd risk factors longitudinally and the association with carotid imt progression in youth with type 1 diabetes ( 14 ) . in a german cohort of 70 youth with type 1 diabetes , dalla pozza et al .
( 14 ) demonstrated that cvd risk factors , including bmi z score ( bmiz ) , systolic bp , and hba1c , worsened over time .
they also found that baseline hba1c and baseline and follow - up systolic bp were significant predictors of change in carotid imt over 4 years .
cohort , and no study has attempted to quantify the burden of cvd risk factors over time on carotid imt .
thus , the aims of the current study were 1 ) to evaluate cvd risk factors over time in youth with type 1 diabetes by using measurements that incorporate risk factor data from a baseline and follow - up visit , and 2 ) to determine the association between the burden of cvd risk factors over time and follow - up carotid imt .
we hypothesized that a worse cvd risk factor burden over time will be associated with a higher carotid imt at follow - up .
participants in this study were enrolled in search cvd , an ancillary study to the search for diabetes in youth that was conducted in two of the five search centers ( colorado and ohio ) .
extensive details of the main search study have been published and are summarized by hamman et al .
participants were eligible for search cvd if they had physician - diagnosed type 1 diabetes .
the baseline search visit of 406 participants with type 1 diabetes was conducted in 20042005 and included questionnaires , demographics , anthropometrics , and laboratory data .
a follow - up search cvd visit was conducted between 2009 and 2011 , where questionnaires , demographics , anthropometrics , and laboratory data were repeated and carotid imt measurements were obtained .
the goal of the follow - up study was to recruit > 200 adolescents with type 1 diabetes from the original cohort .
this report includes 298 youth who completed both baseline and follow - up search cvd visits ( 16,17 ) .
the study was reviewed and approved by each local institutional review board , and all participants provided written informed consent or assent .
the baseline and follow - up research visits followed the same standard protocol ( 16,17 ) .
medications , including short - acting insulin , were withheld until blood draw was completed .
race and ethnicity were self - reported , and participants were categorized as non - hispanic white ( nhw ) or other racial / ethnic group ( hispanic , african american , and asian / pacific islander ) .
participants completed standardized questionnaires for medical history , medications , and smoking status ( never , former [ no cigarettes in the past 30 days ] , or current ) ( 18 ) . height and weight were measured twice during each visit and averaged .
bmi was calculated as an average of two measures of weight ( kg ) divided by height in meters squared , and age and sex - specific bmiz were derived ( 19 ) .
resting systolic and diastolic bps were measured three times with an aneroid sphygmomanometer and averaged .
mean arterial pressure ( map ) was calculated as ( [ 2 diastolic bp ] + systolic bp ) / 3 . measurements of hba1c , total cholesterol , triglycerides , and hdl cholesterol ( hdl - c ) were performed as previously described ( 17 ) .
ldl cholesterol ( ldl - c ) was calculated by the friedewald equation or measured by beta quantification if triglycerides were 400 mg / dl . the thresholds for defining cvd risk factors in this study were generated from published criteria for ideal targets in youth with diabetes ( 2022 ) .
cvd risk factors were defined as present if1 ) bmi 85th percentile for sex and age;2 ) systolic or diastolic bp 90th percentile for sex , age , and height;3 ) ldl - c 130 mg / dl;4 ) hdl - c 30 mg / dl;5 ) triglycerides 130 mg / dl if age 10 years or 100 mg / dl if age < 9 years;6 ) hba1c 7.5% ; or7 ) patient - reported status as a current smoker .
1 ) bmi 85th percentile for sex and age ; 2 ) systolic or diastolic bp 90th percentile for sex , age , and height ; 5 ) triglycerides 130 mg / dl if age 10 years or 100 mg / dl if age < 9 years ; 7 ) patient - reported status as a current smoker . carotid imt measurements
were obtained using standardized b - mode ultrasound images from the right- and left - side neck at the common , bifurcation ( bulb ) , and internal carotid arteries in the longitudinal and transverse views .
all ultrasound images were obtained with a variable frequency linear array probe ( 512 mhz ) .
pulsed doppler echocardiographic measurements were obtained at the internal carotid artery to confirm correct placement .
images were obtained at the predetermined angles of 90 , 120 , and 150 on the right side and 210 , 240 , and 270 on the left side for each participant .
multiple loops were stored , burned to disk , and transmitted to the vascular reading center in ohio for reading of far wall mean imt by a manual trace method ( amicas vericis software , merge healthcare , chicago , il ) . a mean imt value calculated by averaging the imt measurements from the six predetermined angles for each carotid segment is reported .
analyses of carotid studies on > 800 participants had coefficients of variability for all carotid measures ranging from 1.8 to 5.5% , indicating good reproducibility within published guidelines ( 10 ) .
differences between baseline and follow - up anthropometrics and cvd risk factors were tested with paired t tests for continuous variables or mcnemar test for categorical variables .
cvd risk factor thresholds are as described in definitions of cvd risk factors . to determine significant cvd risk factors associated with carotid imt , a stepwise approach was taken using general linear models .
all models adjusted for age at baseline ( in years ) , race ( nhw vs. other ) , sex ( male vs. female ) , duration of diabetes at follow - up ( in years ) , and clinic site ( oh vs. co ) .
an area under the curve ( auc ) measurement ( a continuous variable ) for each cvd risk factor ( except smoking ) was derived using baseline and follow - up data and length of time between visits .
models 15 explored individual effects of auc measurements of standard lipids , bp , insulin sensitivity , hba1c , and bmi over time on carotid imt . model 6 assessed the association between current smoking status ( yes / no ) at either the baseline or the follow - up visit and carotid imt .
model 1 assessed the effects of the ldl - c , hdl - c , and triglycerides auc .
map was used instead of systolic or diastolic bp to account for baseline distending pressure of the artery wall ( 23 ) .
model 3 included insulin sensitivity auc because lower insulin sensitivity ( or insulin resistance ) is believed to partially explain some of the increased cvd risk in youth with type 1 diabetes ( 24 ) .
insulin sensitivity was estimated using the following equation : log is = 4.64725 0.02032 waist in cm 0.00235 tg in mg / dl 0.09779 hba1c % .
this equation was developed and validated using direct measurements of glucose disposal rate from euglycemic - hyperinsulinemic clamps ( 25 ) .
model 4 evaluated hba1c auc , model 5 assessed bmiz auc , and model 6 evaluated smoking .
model 7 included all significant variables from models 16 and can be viewed as the overall model .
participants in this study were enrolled in search cvd , an ancillary study to the search for diabetes in youth that was conducted in two of the five search centers ( colorado and ohio ) .
extensive details of the main search study have been published and are summarized by hamman et al .
participants were eligible for search cvd if they had physician - diagnosed type 1 diabetes .
the baseline search visit of 406 participants with type 1 diabetes was conducted in 20042005 and included questionnaires , demographics , anthropometrics , and laboratory data .
a follow - up search cvd visit was conducted between 2009 and 2011 , where questionnaires , demographics , anthropometrics , and laboratory data were repeated and carotid imt measurements were obtained .
the goal of the follow - up study was to recruit > 200 adolescents with type 1 diabetes from the original cohort .
this report includes 298 youth who completed both baseline and follow - up search cvd visits ( 16,17 ) .
the study was reviewed and approved by each local institutional review board , and all participants provided written informed consent or assent .
the baseline and follow - up research visits followed the same standard protocol ( 16,17 ) .
medications , including short - acting insulin , were withheld until blood draw was completed .
race and ethnicity were self - reported , and participants were categorized as non - hispanic white ( nhw ) or other racial / ethnic group ( hispanic , african american , and asian / pacific islander ) .
participants completed standardized questionnaires for medical history , medications , and smoking status ( never , former [ no cigarettes in the past 30 days ] , or current ) ( 18 ) . height and weight were measured twice during each visit and averaged .
bmi was calculated as an average of two measures of weight ( kg ) divided by height in meters squared , and age and sex - specific bmiz were derived ( 19 ) .
resting systolic and diastolic bps were measured three times with an aneroid sphygmomanometer and averaged .
mean arterial pressure ( map ) was calculated as ( [ 2 diastolic bp ] + systolic bp ) / 3 . measurements of hba1c , total cholesterol , triglycerides , and hdl cholesterol ( hdl - c ) were performed as previously described ( 17 ) . ldl cholesterol ( ldl - c )
was calculated by the friedewald equation or measured by beta quantification if triglycerides were 400 mg / dl .
the thresholds for defining cvd risk factors in this study were generated from published criteria for ideal targets in youth with diabetes ( 2022 ) .
cvd risk factors were defined as present if1 ) bmi 85th percentile for sex and age;2 ) systolic or diastolic bp 90th percentile for sex , age , and height;3 ) ldl - c 130 mg / dl;4 ) hdl - c 30 mg / dl;5 ) triglycerides 130 mg / dl if age 10 years or 100 mg / dl if age < 9 years;6 ) hba1c 7.5% ; or7 ) patient - reported status as a current smoker .
1 ) bmi 85th percentile for sex and age ; 2 ) systolic or diastolic bp 90th percentile for sex , age , and height ; 5 ) triglycerides 130 mg / dl if age 10 years or 100 mg / dl if age < 9 years ; 7 ) patient - reported status as a current smoker .
carotid imt measurements were obtained using standardized b - mode ultrasound images from the right- and left - side neck at the common , bifurcation ( bulb ) , and internal carotid arteries in the longitudinal and transverse views .
all ultrasound images were obtained with a variable frequency linear array probe ( 512 mhz ) .
pulsed doppler echocardiographic measurements were obtained at the internal carotid artery to confirm correct placement .
images were obtained at the predetermined angles of 90 , 120 , and 150 on the right side and 210 , 240 , and 270 on the left side for each participant .
multiple loops were stored , burned to disk , and transmitted to the vascular reading center in ohio for reading of far wall mean imt by a manual trace method ( amicas vericis software , merge healthcare , chicago , il ) . a mean imt value calculated by averaging the imt measurements from the six predetermined angles for each carotid segment is reported .
analyses of carotid studies on > 800 participants had coefficients of variability for all carotid measures ranging from 1.8 to 5.5% , indicating good reproducibility within published guidelines ( 10 ) .
differences between baseline and follow - up anthropometrics and cvd risk factors were tested with paired t tests for continuous variables or mcnemar test for categorical variables .
cvd risk factor thresholds are as described in definitions of cvd risk factors . to determine significant cvd risk factors associated with carotid imt , a stepwise approach was taken using general linear models .
all models adjusted for age at baseline ( in years ) , race ( nhw vs. other ) , sex ( male vs. female ) , duration of diabetes at follow - up ( in years ) , and clinic site ( oh vs. co ) .
an area under the curve ( auc ) measurement ( a continuous variable ) for each cvd risk factor ( except smoking ) was derived using baseline and follow - up data and length of time between visits .
models 15 explored individual effects of auc measurements of standard lipids , bp , insulin sensitivity , hba1c , and bmi over time on carotid imt .
model 6 assessed the association between current smoking status ( yes / no ) at either the baseline or the follow - up visit and carotid imt .
model 1 assessed the effects of the ldl - c , hdl - c , and triglycerides auc .
map was used instead of systolic or diastolic bp to account for baseline distending pressure of the artery wall ( 23 ) .
model 3 included insulin sensitivity auc because lower insulin sensitivity ( or insulin resistance ) is believed to partially explain some of the increased cvd risk in youth with type 1 diabetes ( 24 ) .
insulin sensitivity was estimated using the following equation : log is = 4.64725 0.02032 waist in cm 0.00235 tg in mg / dl 0.09779 hba1c % .
this equation was developed and validated using direct measurements of glucose disposal rate from euglycemic - hyperinsulinemic clamps ( 25 ) .
model 4 evaluated hba1c auc , model 5 assessed bmiz auc , and model 6 evaluated smoking .
model 7 included all significant variables from models 16 and can be viewed as the overall model .
characteristics of search participants at baseline and follow - up are presented in table 1 . at the initial visit , youth with type 1 diabetes were a mean age of 13.3 2.9 years ( range 7.621.3 years ) and had an average disease duration of 3.6 3.3 years .
nhw accounted for 87.6% of the cohort , and 53.7% of the cohort was male . at baseline ,
four participants reported taking an ace inhibitor / angiotensin receptor blocker , and one reported use of a lipid - lowering medication .
characteristics of search cvd study participants at the baseline and follow - up visits data are mean sd or n ( % ) .
p values were determined by paired t tests for continuous variables and mcnemar test for categorical variables .
follow - up data were obtained at a mean age of 19.2 2.7 years , when the average duration of type 1 diabetes was 10.1 3.9 years . at follow - up ,
cvd risk factors , including bmiz , systolic and diastolic bp , hba1c , lipid levels , and insulin sensitivity , were all significantly worse at follow - up except for ldl - c , which was not significantly different . at follow - up ,
12 ( 3.0% ) participants reported taking an ace inhibitor / angiotensin receptor blocker , and 25 ( 6.0% ) reported taking a lipid - lowering drug .
table 2 shows the frequency of cvd risk factors at baseline and follow - up . at baseline ,
high hba1c was the most common cvd risk factor , present in 72.6% of the cohort .
high ldl - c level was the most common lipid abnormality , present in 10.3% .
cvd risk factors at baseline and follow - up ( n = 298 ) data are n ( % ) . elevated defined as bmi 85th percentile for sex and age ; systolic or diastolic bp 90th percentile for sex , age , and height ; ldl - c 130 mg / dl ; and triglycerides 130 mg / dl if age 10 years or 100 mg / dl if age < 9 years .
are the percentage of participants with zero to five cardiovascular risk factors at baseline and follow - up data .
cardiovascular risk factors were bmi 85th percentile for sex and age ; systolic or diastolic bp 90th percentile for sex , age , and height ; ldl - c 130 mg / dl ; and triglycerides 130 mg / dl if age 10 years or 100 mg / dl if age < 9 years .
* mean number of risk factors was higher from baseline to follow - up ( p < 0.05 ) . at follow - up , the frequency of participants in each risk category increased significantly , except for hdl - c where the frequency decreased significantly from baseline to follow - up ( all p < 0.05 ) . at follow - up ,
high bmi was present in more than one - third of the cohort , and high triglyceride levels were the most frequently observed lipid abnormality ( 32.3% ) .
figure 1 shows that more than one - half ( 53% ) of participants had two or more cvd risk factors at follow - up . at follow - up , the mean imt for youth with type 1 diabetes in the common carotid was 0.60 0.10 mm , the bulb imt was 0.62 0.10 mm , and the internal imt was 0.55 0.12 mm .
general linear models were constructed to explore risk factors associated with follow - up common , bulb , and internal carotid imt ( table 3a c ) .
older age at the baseline visit and male sex were significantly associated with all carotid imt outcomes .
hdl - c auc ( model 1 ) , map ( model 2 ) , insulin sensitivity auc ( model 3 ) , and bmiz auc ( model 5 ) were significantly associated with follow - up common carotid imt after adjusting for age , race , sex , duration of diabetes , and clinic site .
however , in the final model ( model 7 ) for common carotid imt that included each significant cv risk factor , only bmiz was significant .
similarly , hdl - c auc , insulin sensitivity auc , and bmiz auc were associated with follow - up internal carotid imt , but in the final model , only bmiz auc was significant .
auc and smoking were not associated with any carotid imt outcomes in either the individual models or the final model .
of all the cvd risk factors explored , higher bmiz auc was the only one significantly associated with follow - up common and internal carotid imt in multivariable analyses .
a borderline association was also observed for bmiz auc and the carotid bulb imt ( p = 0.075 ) .
predictors associated with follow - up common , bulb , and internal carotid imt bolded p values are significant .
table 2 shows the frequency of cvd risk factors at baseline and follow - up . at baseline ,
high hba1c was the most common cvd risk factor , present in 72.6% of the cohort .
high ldl - c level was the most common lipid abnormality , present in 10.3% .
cvd risk factors at baseline and follow - up ( n = 298 ) data are n ( % ) . elevated defined as bmi 85th percentile for sex and age ; systolic or diastolic bp 90th percentile for sex , age , and height ; ldl - c 130 mg / dl ; and triglycerides 130 mg / dl if age 10 years or 100 mg / dl if age < 9 years .
are the percentage of participants with zero to five cardiovascular risk factors at baseline and follow - up data .
cardiovascular risk factors were bmi 85th percentile for sex and age ; systolic or diastolic bp 90th percentile for sex , age , and height ; ldl - c 130 mg / dl ; and triglycerides 130 mg / dl if age 10 years or 100 mg / dl if age < 9 years .
* mean number of risk factors was higher from baseline to follow - up ( p < 0.05 ) . at follow - up , the frequency of participants in each risk category increased significantly , except for hdl - c where the frequency decreased significantly from baseline to follow - up ( all p < 0.05 ) .
at follow - up , high bmi was present in more than one - third of the cohort , and high triglyceride levels were the most frequently observed lipid abnormality ( 32.3% ) .
figure 1 shows that more than one - half ( 53% ) of participants had two or more cvd risk factors at follow - up .
at follow - up , the mean imt for youth with type 1 diabetes in the common carotid was 0.60 0.10 mm , the bulb imt was 0.62 0.10 mm , and the internal imt was 0.55 0.12 mm .
general linear models were constructed to explore risk factors associated with follow - up common , bulb , and internal carotid imt ( table 3a c ) .
older age at the baseline visit and male sex were significantly associated with all carotid imt outcomes .
hdl - c auc ( model 1 ) , map ( model 2 ) , insulin sensitivity auc ( model 3 ) , and bmiz auc ( model 5 ) were significantly associated with follow - up common carotid imt after adjusting for age , race , sex , duration of diabetes , and clinic site .
however , in the final model ( model 7 ) for common carotid imt that included each significant cv risk factor , only bmiz was significant .
similarly , hdl - c auc , insulin sensitivity auc , and bmiz auc were associated with follow - up internal carotid imt , but in the final model , only bmiz auc was significant .
auc and smoking were not associated with any carotid imt outcomes in either the individual models or the final model .
of all the cvd risk factors explored , higher bmiz auc was the only one significantly associated with follow - up common and internal carotid imt in multivariable analyses . a borderline association was also observed for bmiz auc and the carotid bulb imt ( p = 0.075 ) .
predictors associated with follow - up common , bulb , and internal carotid imt bolded p values are significant .
this study demonstrates for the first time to our knowledge that the degree and burden of cvd risk factors increases over time in youth with type 1 diabetes .
this study also shows that higher bmiz over time was the only modifiable risk factor associated with follow - up carotid imt .
previous cross - sectional studies have demonstrated that adolescents with type 1 diabetes have worse cvd risk profiles and higher carotid imt than control subjects ( 813 ) .
risk factors shown to associate with higher imt are age of diabetes onset ; higher adiposity , lipid levels , bp , and hba1c ; and lower vitamin c levels ( 8,9,11 )
. specifically , dalla pozza et al . ( 14 ) found that younger age at diabetes onset , systolic bp ( mean 111.3 11.3 mmhg ) and total cholesterol levels ( mean for females 185 32.0 mg / dl , mean for males 168 28.4 mg / dl ) were significantly associated with a higher common carotid imt in adolescents at age 14 years .
( 9 ) found hba1c ( mean 9.8 1.5% ) was borderline associated with a higher carotid imt ( r = 0.39 , p = 0.05 ) . before the current study ,
no published reports had assessed the impact of changes in cvd risk factors and carotid imt in u.s .
a study conducted in 70 german children with type 1 diabetes ( mean baseline age 12.6 2.5 years ) examined longitudinally the effect of cvd risk factors on carotid imt , reporting that over 4 years , bmiz , systolic bp , and hba1c worsened , whereas ldl - c and hdl - c did not ( 14 ) .
additionally , the authors noted that higher baseline hba1c and higher baseline and follow - up systolic bp were signficantly associated with change in carotid imt over time in linear regression models .
limitations of that study included loss of > 50% of the original cohort , use of individual baseline and follow - up cvd risk factor data instead of an auc measurement that accounts for burden of risk factors over time , and no report of diastolic bp , triglycerides , or insulin sensitivity measurements ( 14 ) . in the current study
, we show that older age ( at baseline ) and male sex were significantly associated with follow - up imt . by using auc measurements
, we also show that a higher bmiz exposure over 5 years was significantly associated with imt at follow - up . from baseline to follow - up , the mean bmi increased from within normal limits ( 21.1 4.3 kg / m ) to overweight ( 25.1 4.8 kg / m ) , defined as a bmi 25 kg / m in adults ( 26,27 ) . this large change in bmi may explain why bmiz was the only modifiable risk factor to be associated with follow - up imt in the final models . whether the observed increase in bmiz over time is part of the natural evolution of diabetes , aging in an obesogenic society , or a consequence of intensive insulin therapy is not known . however , this finding points to obesity as a common cvd risk factor in both type 1 and type 2 diabetes , despite the clear differences in the pathophysiology of the two types of diabetes .
weight loss in obese adolescents has been shown to be beneficial at improving carotid imt ( 28,29 ) .
whether weight loss improves carotid imt and reduces cvd risk in youth with type 1 diabetes remains to be determined . after adjusting for baseline covariates , we found no association between lipids , bp , and hba1c over time and follow - up imt .
the reasons for the lack of independent association are not known , but we postulate that although total cholesterol , hdl - c , triglycerides , and systolic and diastolic bp worsened over time , the mean values at baseline and follow - up remained below thresholds defined as cvd risk factors ( 2022 ) .
this could explain the discrepant results between our study and the study by dalla pozza et al .
( 14 ) , in which an association between mean systolic bp and change in imt over time was observed .
cohort was in the prehypertension range ( mean systolic bp 122 11.5 mmhg ) , whereas that in the current study at follow - up bp was in the normal range ( mean systolic bp 112 10 mmhg ) .
alternatively , lipid levels and bp may only be important cvd risk factors when duration of diabetes has been > 5 years .
similar findings have been observed in the diabetes control and complications trial ( dcct ) and its follow - up cohort the epidemiology of diabetes interventions and complications ( edic ) study , where traditional cvd factors did not associate with future imt until nearly one decade later ( 30 ) .
this may also explain why hba1c auc , although clearly abnormal at both baseline and follow - up , was not associated with follow - up carotid imt in the current study .
current smoking status ( at either baseline or follow - up ) was also not associated with carotid imt .
potential explanations for this lack of association may be due to underreporting of self - reported smoking behaviors ( 31 ) .
additionally , the duration of smoking may have been short , or the quantity of cigarettes smoked may have been too small to have detectable effects on the vasculature . finally , there may be a threshold effect of smoking ( in terms of both dose and duration ) at which accelerated vascular changes occur .
given that prior work in middle - aged adults has clearly documented adverse effects of smoking on the vasculature ( 32 ) , additional studies with quantification of cotinine are needed before conclusions can be drawn about the effects of smoking on carotid imt in youth with type 1 diabetes . similar to studies in adults ( 30 ) , we identified few risk factors that associate with follow - up carotid imt .
other work , including previously published data from our group , suggested that worsening insulin resistance ( or decreased insulin sensitivity ) may be an important cvd risk factor in youth with type 1 diabetes ( 33 ) .
however , after adjusting for bmiz in the current study , we did not find a statistically significant association between insulin sensitivity auc and follow - up imt , despite the worsening of insulin sensitivity over time .
data from the dcct / edic cohorts have suggested nontraditional risk factors , including acute phase reactants , thrombolytic factors , cytokines / adipokines ( 34 ) , oxidized ldl , and advanced glycation end products ( 30 ) may be important biomarkers of increased cvd risk in adults with type 1 diabetes . however , many of these nontraditional risk factors , including acute phase reactants , thrombolytic factors , and cytokines / adipokines , were not found to associate with imt until 812 years after the dcct ended , at the time when traditional cvd risk factors were also found to predict imt . collectively , these findings suggest that many traditional and nontraditional risk factors are not identified as relevant until later in the atherosclerotic process and highlight the critical need to better identify risk factors that may influence carotid imt early in the course of type 1 diabetes because these may be important modifiable cvd risk factors of focus in the adolescent population
. strengths of the current study include a large cohort of youth with type 1 diabetes , follow - up cvd risk factor data after 5 years ( the longest follow - up to date in youth ) , and the ability to evaluate the association between cvd risk factors over time and follow - up imt in a young adolescent cohort ( mean age 18 years at follow - up ) . limitations of the study include carotid imt measurements obtained only at one time point , lack of physical activity data , and the inability to assess nontraditional biomarkers .
additionally , we quantified adiposity only in terms of bmi , which does not capture information on lean body mass or types of fat . finally , generalizability of the results to other type 1 diabetes cohorts with a worse cvd risk profile may be limited
. however , the risk factor profile we report is consistent with that of the larger search cohort ( 35 ) , large type 1 diabetes cohorts in the u.s . and u.k .
in conclusion , we demonstrate that the cvd risk factor burden increases over time in youth with type 1 diabetes . although bmiz was the only identified risk factor to predict follow - up imt at this age , it is possible that increases in dyslipidemia , bp , smoking , and hba1c are related to carotid imt but only after longer duration of exposure .
Output:
| objectiveyouth with type 1 diabetes have worse cardiovascular ( cv ) risk factors and higher carotid intima - media thickness ( imt ) than their peers without diabetes . whether the burden of cv risk factors over time is associated with carotid imt at follow - up in youth with type 1 diabetes is not known.research design and methodstwo hundred ninety - eight youth with type 1 diabetes ( mean age 13.3 2.9 years , 87.6% non - hispanic white , 53.7% male ) had two study visits 5 years apart .
cv risk factors , including bmi , lipids , blood pressure , hemoglobin a1c , and smoking status , were assessed at both visits , and carotid imt was measured at follow - up using b - mode ultrasonography .
linear regression models with an area under the curve measurement that incorporated the baseline and follow - up cv risk factors were used to evaluate the relationship with carotid imt at follow-up.resultsall cv risk factors worsened significantly over time ( except ldl cholesterol ) ( p < 0.05 ) . from baseline to follow - up , the number of abnormal cv risk factors also increased ( p < 0.05 ) .
predictors of carotid imt were older age , male sex , and higher bmi z score area under the curve ( all p < 0.05).conclusionsthe cv risk factor burden increases over time in youth with type 1 diabetes .
bmi z score was the only modifiable cv risk factor that predicted carotid imt .
this study highlights the critical need to better understand the risk factors that influence carotid imt early in the course of type 1 diabetes . |
PubmedSumm118732 | ***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: whilst clinical studies have shown encouraging long - term clinical performance , failure of these devices can still occur .
specifically , the clinical complications and unexpected failure of hip prostheses linked to edge loading have been reported recently ( langton et al . , 2011 ; walter et al . , 2011 ; kwon et al . ,
this edge loading , defined as the contact of the head on the rim of the liner , has been associated with many factors , including patient activity , prosthesis design , surgical positioning and material combinations ( mellon et al . , 2011 ;
; harris , 2012 ; underwood et al . , 2012 ) . in particular , the primary contribution of the rotational and translational mal - positioning of the components to edge loading has been identified and well summarised ( fisher , 2011 ; harris , 2012 ) .
rotational mal - positioning is defined clinically as the steep inclination and excessive anteversion of the acetabular component while translational mal - positioning , also termed as microseparation , is described as the misalignment of the centres of the head and the cup ( nevelos et al . , 1999 , 2000 ) .
in vitro studies have shown that the introduction of microseparation in a hip joint simulator can successfully reproduce clinically relevant wear rates , wear patterns and wear particle distributions for both metal - on - metal ( mom ) and ceramic - on - ceramic ( coc ) articulations ( nevelos et al .
, 2000 ; stewart et al . , 2001 ) . these outcomes , however , could not be replicated under standard walking conditions with either a normal or a steep cup angle ( williams et al . , 2008 ;
this indicates that microseparation of the femoral head and the acetabular cup occurs in vivo during normal gait , a phenomenon which has also been observed with the aid of fluoroscopy ( dennis et al . , 2001 ; komistek et al . ,
microseparation usually occurs during the swing phase and is considered to be as a result of muscle weakness , mal - positioning of the acetabular cup or offset deficiency of the femoral head ( ryou et al . ,
these factors cause the femoral head to be moved laterally relative to the acetabular cup during the swing phase .
when a load is applied in the stance phase , the femoral head is moved upward , leading to edge loading , which can have a significant consequence on the wear and biomechanics of the total hip replacements ( thrs ) .
the effect of edge loading induced by microseparation on the biomechanics and performance of hard - on - hard articulations has been documented ( manaka et al . , 2004 ; williams et al .
, 2006 ; leslie et al . , 2009 ; al - hajjar et al . , 2010 ) . in mom articulations ,
edge loading can produce accelerated wear of whole joints ( williams et al . , 2006 ; leslie et al . , 2009 ) and
lead to metallosis , abnormal peri - prosthetic soft - tissue reactions such as pseudotumours ( kwon et al . ,
edge loading has been associated with accelerated articulating wear , squeaking , stripe wear on either the head or the cup , and in some situations , the fracture of the components ( nevelos et al . , 2001 ;
2010 ) . finite element ( fe ) studies have also been conducted to examine the stresses in the components due to edge loading and have shown a 3 - 8 fold increase in the stress of the components in coc hips compared to that under normal loading conditions ( mak et al . , 2002 ; sariali et al . , 2012 ) .
all these studies have provided significant indication that edge loading due to the rotational and translational malposition of the components has a negative impact on the thrs . however , whilst edge loading has been widely investigated for hard - on - hard articulations , fewer studies have been carried out for hard - on - soft combinations , especially with respect to the contact mechanics of modular mop thr under microseparation conditions .
the aim of the present study was therefore to investigate the contact mechanics of a modular mop thr under edge loading conditions due to the microseparation and rotational malpositioning of the components using fe methods .
a typical commercially available modular mop total hip system , consisting of metal shell , polyethylene liner and metallic femoral head , was analysed .
the nominal diameters of the femoral head and inner surface of the polyethylene liner were 36 mm and 36.6 mm respectively , giving a radial clearance of 0.3 mm between the femoral head and the liner .
the outer diameter of the acetabular component was assumed to be 54 mm . a polar fenestration with diameter of 20 mm was considered in the central dome region of the metal shell .
a three - dimensional fe model was created to simulate the position of both the femoral and acetabular components implanted in a hemi - pelvic bone model ( fig .
the hemi - pelvic bone model consists of a cancellous bone region surrounded by a uniform cortical shell of 1.5 mm thickness ( udofia et al . , 2007 ) .
all the materials in the fe model were modelled as homogenous , isotropic and linear elastic except the polyethylene liner which was modelled as non - linear elastic - plastic with the plastic stress - stain constitutive relationship showing in fig . 2 ( liu , 2005 ) .
the mechanical properties for the materials are presented in table 1 ( udofia et al . , 2007 ; hua et al . , 2012 ) .
the femoral component was assumed to be rigid because the elastic modulus of the metallic femoral component is at least two orders of magnitude greater than that of the polyethylene material .
the total number of elements for the fe model was approximately 92 , 000 , predominantly consisting of eight - node brick elements , six - node wedge elements , four - node tetrahedral elements and three - node shell elements . the sensitivity of the results to the mesh was carried out in the cases of standard conditions and 1500 m microseparation conditions under cup inclination angle of 65 , and results showed that when the number of the elements was doubled , the change in any of the parameters of interest was within 5% .
a sliding contact formulation was used both on the articulating surface and at the metal shell / liner interface , with friction coefficients of 0.083 and 0.15 respectively ( ramero et al . , 2007 ; amirouche et al . ,
the nodes situated at the sacroiliac joint and about the pubic symphysis were fully constrained to simulate the sacral and pubic support of the pelvic bone .
the interface between the bone and the implant was fully bonded to simulate a situation where the porous sintered coating and in - grown bone were well bonded ( fig .
the rotation of the femoral head was fully constrained while the translation was restrained to ensure that the femoral head was only allowed to move along the loading directions .
the fe analysis was performed using abaqus software package ( version 6.9 , dassault systmes simulia corp . , providence , united states ) .
the validation of the fe model was presented in detail in a previous study ( hua et al . , 2013 ) , which has shown good agreements of contact areas ( within 12% ) between the fe predictions and the experimental measurements using leeds prosim hip joint simulator .
different loads with magnitude of 2500 n and different directions of 10 medially , 0 ( vertical ) and 10 laterally were applied through the centre of the femoral head .
four cup inclination angles , varying between 35 and 65 in 10 increments , and 12 lateral microseparation distances of 0 m , 60 m , 100 m , 150 m , 200 m , 300 m , 400 m , 500 m , 800 m , 1000 m , 1500 m and 2000 m were considered in the present study .
the definition of the cup inclination angles and head lateral microseparation is shown in fig .
edge loading appeared for lower values of microseparation of the head as the cup inclination angles increased ( fig .
there was no substantial elevation in the stresses and plastic strain in the liner at the initial occurrence of edge loading .
however , the stresses and strain increased continuously when the microseparation distances increased ( figs . 5 and 7 ) . for all cup inclination
angles considered , the maximum von mises stress of the liner and the maximum contact pressure on the articulating surface and backside surface of the liner increased markedly by 88%160% , 135%256% , and 117%250% respectively when the microseparation distances increased to 2000 m compared to those under standard conditions ( fig . 5 ) . under standard conditions ,
as the cup inclination angles increased , all of the above parameters increased as well .
however , the increase of the maximum von mises stress and contact pressure induced by higher cup inclination angles became negligible as the microseparation distances increased ( fig .
the maximum equivalent plastic strain in the liner was predicted to be 5.610 under standard conditions and increased to 34.710 under 1000 m microseparation conditions for cup inclination angle of 45 ( fig .
angles considered , the maximum equivalent plastic strain in the liner increased substantially with increased microseparation distances ( fig .
the maximum equivalent plastic strain in the liner under microseparation conditions of 2000 m was predicted to be approximately six times that under standard conditions ( fig .
the model with a load direction of 10 laterally predicted higher maximum von mises stress , maximum contact pressure and maximum equivalent plastic strain compared to that with a vertical load direction and a load direction of 10 medially ( fig .
the discrepancies of these stresses and strain increased from 1.33 mpa , 1.89 mpa and 1.3610 under standard conditions to 2.7 mpa , 4.19 mpa and 4.1310 under 800 m microseparation conditions respectively , which then decreased to 0.59 mpa , 1.92 mpa and 0.7710 under 2000 m microseparation conditions ( fig . 8) .
edge loading as an adverse condition which could cause clinical problems has been widely investigated for hard - on - hard bearing designs ( manaka et al . , 2004 ; williams et al . , 2006 ; kwon et al . ,
however , for hard - on - soft combinations , limited work has been undertaken and the effect of edge loading on the behaviour of these articulations deserves further attention .
the aims of the present study were therefore to focus on edge loading in a current modular mop thr , and to examine the effect of cup inclination angles and microseparation on edge loading and contact mechanics of a modular mop thr .
the fe analysis in the present study showed that with increased cup inclination angles , the microseparation distances required to generate edge loading decreased , suggesting that a steep cup inclination angle could potentially facilitate the occurrence of edge loading when the head lateral microseparation exists .
this highlights the increased instability of hip prostheses with steep cups in vivo and was found to be consistent with previous clinical studies , indicating that cups positioned with high inclination angles were more likely to suffer from edge loading ( nevelos et al .
the contact areas on the articulating surface were located about the superior region of the liner under standard conditions , and were found to centralise at the rim of the liner when the microseparation distances increased to 2000 m , leading to a stripe contact area at the rim of the liner and elevated stresses in this area .
indeed , the fe predictions from this study showed that plastic deformation of the liner occurs under both standard conditions and microseparation conditions .
however , there was a substantial increase in the equivalent plastic strain as the microseparation distance increased , indicating severe plastic deformation of the liner under microseparation conditions , which has also been observed in an in vitro study ( williams et al . , 2003 ) .
the severe plastic deformation at the rim of the liner could potentially induce creep and fatigue of the liner ( penmetsa et al .
, 2006 ; hertzberg and manson , 1980 ) , and also pitting and delamination of the surface at this area , leading to fatigue damage and fracture of the component ( edidin et al . , 1999 ) .
the contact stresses on both the frontside articulating surface and backside surface of the liner were found to increase as the cup inclination angles increased .
this was consistent with a previous study ( kurtz et al . , 1997 ) .
however , the differences of contact stresses induced by different cup inclination angles became negligible due to the lateral microseparation of the component .
this indicated that in case of hip laxity , the dominating factor to affect the biomechanics of the modular mop thr is the level of microseparation , rather than acetabular component position .
it has been shown that clinically a steep cup inclination angle may increase the frequency of occurrence of microseparation at a certain level ( nevelos et al . , 1999 , 2000 ) .
microseparation is believed to generate elevated both localised wear and global wear for hard - on - hard articulations ( stewart et al .
, 2001 ; leslie et al . , 2009 ; al - hajjar et al . , 2010 )
however , it may not be true for hard - on - soft combinations . the limited experimental work to date with ceramic - on - polyethylene ( cop ) bearings did not indicate an increase in surface wear when inferior and lateral translations of 0.7 mm were introduced ( williams et al . , 2003 ) .
however , the present study has shown that the introduction of microseparation to the gait cycle did increase the von mises stresses in the liner and contact stresses on the articulating surface , and more importantly the plastic strain in the liner .
this highlights the importance of the surgical technique in positioning the centre of the head in the centre of the cup to avoid head lateral displacement and thus reduce the maximum stress and strain in the liner component .
the magnitude and orientation of the contact forces were reported to vary over the gait cycle ( bergmann et al . , 2001 ) , which were found to affect the biomechanical behaviour of the hip replacements ( kurtz et al . , 1997 ) .
the present study showed that with a lateral direction of load , the stress and plastic strain in the liner and contact pressure on the articulating surface were predicted to be higher compared to the conditions with a vertical direction and a medial direction of loads .
this phenomenon was found to be aggravated under moderate microseparation conditions ( i.e. 500 m and 800 m microseparation conditions ) where the discrepancies of predictions of stresses and plastic strain among the models with different load directions were 23 times that under standard conditions .
this again highlights the importance of the surgical technique in avoiding the head lateral microseparation in clinical practice .
first of all , the soft tissues surrounding the hip such as muscles and ligaments may have an important role in the stability of the hip replacement ( elkins et al . , 2011 ) .
secondly , the head lateral microseparation during gait is actually a dynamic process ( lombardi et al . , 2000 ;
in addition , the magnitude and orientation of the contact forces varied over gait cycle .
however , in the present study , a static analysis with fixed load was performed and the effect of dynamic impact on the stresses and strain was not explicitly considered .
nevertheless , a contact force of 2500 n was applied in the present study , which was higher than physiological loading during gait ( bergmann et al . , 2001 ) and can be expected to offset the dynamic impact .
different load directions of 10 medially and 10 laterally as well as a vertical load were also considered under microseparation conditions in the present study to simply represent the different load directions during gait .
even so , the dynamic process of microseparation during gait and exact physiological loading conditions should be simulated and addressed in the models in future studies
. additionally , the femoral head was loaded at its centre in the present study , without considering an off - centre location . however , as the femoral head was assumed to be rigid , the models would predict identical results with respect to the contact pressure on the bearing surface and the plastic strain of the liner irrespective of the location of applied loading on the femur .
moreover , the material properties of the liner used in the present study was suitable for conventional uhmwpe .
however , for current mop hip replacement , there is a higher usage of cross - linked uhmwpe , which has a 23 times higher youngs modulus compared to the conventional uhmwpe ( lewis , 2001 ) . in order to examine the effect of material properties , sensitivity analysis of model predictions to uhmwpe material properties
were conducted and the results showed that when the youngs modulus of uhmwpe changed from 1 gpa2.5 gpa , the maximum contact pressures and equivalent plastic strain in the liner increased by about 5% and 4% respectively under standard conditions , and about 7% and 8% respectively under 1000 m microseparation conditions .
another limitation in the present simulation was that the interface between the bone and metal shell was fully bonded to simulate a solid bone - implant osseointegration situation .
however , in reality , it is impossible to ensure perfect integration between the bone and the prosthesis with current surgical techniques , especially in the early stage of implantation . in order to assess the effect of such assumption on the predicted results , additional simulations considering a frictional contact interface between the bone and the implant were conducted .
the simulation results showed that the contact pressures at the articulating surface and the equivalent plastic strain of the liner decreased by about 13.4% and 17.3% when a friction coefficient of 0.6 ( ramamurti et al .
, 1997 ; mischler and pax , 2002 ) was considered at the bone / metal shell interface under microseparation conditions of 1000 m .
in addition , a certain degree of micromotion ( about 38 m ) for the implants was predicted at this situation .
this micromotion would contribute to the loosening and instability of the implants , especially at the primary stage of implantation . despite these limitations listed above
, this study did suggest that the head lateral microseparation would cause edge loading and induce a marked increase in the von mises stresses of the liner and contact stresses on the articulating surfaces , as well as severe plastic deformation of the liner , and that steep cup inclination angles would facilitate edge loading .
therefore , clinically it is important to avoid conditions that may lead to edge loading , which means reducing the levels of rotational and translational mal - positioning of the head and cup .
Output:
| edge loading can negatively impact the biomechanics and long - term performance of hip replacements .
although edge loading has been widely investigated for hard - on - hard articulations , limited work has been conducted for hard - on - soft combinations .
the aim of the present study was to investigate edge loading and its effect on the contact mechanics of a modular metal - on - polyethylene ( mop ) total hip replacement ( thr ) .
a three - dimensional finite element model was developed based on a modular mop bearing .
different cup inclination angles and head lateral microseparation were modelled and their effect on the contact mechanics of the modular mop hip replacement were examined .
the results showed that lateral microseparation caused loading of the head on the rim of the cup , which produced substantial increases in the maximum von mises stress in the polyethylene liner and the maximum contact pressure on both the articulating surface and backside surface of the liner .
plastic deformation of the liner was observed under both standard conditions and microseparation conditions , however , the maximum equivalent plastic strain in the liner under microseparation conditions of 2000 m was predicted to be approximately six times that under standard conditions .
the study has indicated that correct positioning the components to avoid edge loading is likely to be important clinically even for hard - on - soft bearings for thr . |
PubmedSumm118733 | ***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 socially - constructed and culturally - mediated concept of risk is used to give meaning to things , forces , or circumstances that are deemed to pose danger to people or what they value .
risk assessment in various forms has been used for centuries by individuals and societies to evaluate particular hazards that they believe to be of special concern .
after world war ii , many industrialized societies began to view risk from injurious by - products of technology and economic activity as a noxious quality present to varying degrees in diverse geospatial locations and environmental settings . in today s world , the principal method for describing environmental health risks is through a quantitative , or at least semi - quantitative estimation of the likelihood and severity of harm resulting from exposure to recognized hazards .
proponents of this approach assert that risk assessment is a valuable decision - making tool for identifying , evaluating , and resolving environmental health problems .
critics , on the other hand , tend to see it as an ethically suspect , resource - intensive , elitist , never - ending process used by those in power to maintain the status quo . in the united states , the u.s .
environmental protection agency ( epa ) is required by federal statutes , such as the clean air act , safe drinking water act , toxic substances control act ( tsca ) , and federal insecticide , fungicide , and rodenticide act ( fifra ) , to make decisions about safeguarding human health and environmental quality from the harmful effects of environmental hazards .
the conceptual framework underpinning these decisions is often referred to as the risk assessment risk management ( ra - rm ) paradigm .
the ra - rm paradigm consists of three complementary , sequential , and overlapping components : i ) risk - related research to provide necessary scientific information and understanding ; ii ) risk assessment to organize and analyze available scientific data in order to estimate the likelihood , magnitude , and uncertainty of risks ; and iii ) risk management to evaluate both facts and values so as to determine which risks are unacceptable and what , if anything , to do about them . a fourth component , risk communication , is often considered part of the ra - rm paradigm , and refers to efforts aimed at explaining risks and risk - related decisions to stakeholders and responding to their questions and concerns .
the ra - rm paradigm was established in 1983 through publication of the landmark national research council ( nrc ) report , risk assessment in the federal government : managing the process , usually referred to as the red book .
congress in 1863 , which calls on this society of distinguished scholars to provide advice to the u.s .
since it was first enunciated , the ra - rm paradigm has evolved considerably as new research methods and better scientific data became available , and it became obvious that environmental health risks were more complicated and expensive to solve than initially supposed . at the outset
, the process of risk - based decision making was seen as an expert - driven , largely opaque method for justifying decisions by regulatory agencies . over time , however , it has become apparent that regulatory decisions need to be based on more than just technical expertise they need to be informed by input from stakeholders and the public in order to improve the quality , legitimacy , and capacity of risk - based decisions .
the following discussion looks at how public participation in the ra - rm paradigm has evolved since 1983 , where public participation is defined to mean organizational processes adopted by the epa and other regulatory agencies to engage stakeholders , directly affected groups , interested observers , and the general public in decisions about assessment and management of environmental health risks .
the goal is to highlight key changes to the ra - rm process and examine important lessons learned .
the impetus for public participation and the challenges encountered during implementation occur within the context of risk - based decision making by epa and its sister regulatory agencies .
although scientific analysis is a necessary component of these decisions , it is not sufficient , by itself , to ensure proper consideration of tradeoffs among risks , costs , and benefits or their appropriate distribution across human populations .
there is broad consensus as well as statutory requirements that i ) risk - based decisions be founded on the best available scientific evidence and technical judgments , and ii ) that they also take into account the knowledge , values , and preferences of interested and affected parties .
according to the nrc , it is critical , therefore , to acknowledge that decision making about environmental health risks is inherently a political process , which depends not only on factual information , but also on values and preferences and on interpretation of factual information . aside from the statutory requirements
, there are continuing debates about why epa should involve the public as an integral part of the ra - rm paradigm and the costs and benefits of doing so .
those favoring public participation typically base their arguments on normative theories of democracy and collective action or on substantive and instrumental justifications related to improving quality , enhancing legitimacy , and building capacity .
critics , including academics and practitioners concerned about issues of practicality , transaction costs , and efficient decision - making , usually question the basic logic of public involvement in complicated scientific judgments .
they argue on practical grounds that the costs are not justified by the benefits , and that attempts to reach consensus among multiple stakeholders with conflicting values and diverging interests are either unsuccessful or lead to inconsequential results that reflect the lowest common denominator .
the reality is that decisions about the desirability of public involvement and the design of appropriate participation processes are value judgments that reflect the political power of certain stakeholders to influence those choices .
public participation in environmental decision making at the federal level has been institutionalized since 1946 by the administrative procedure act ( apa ) , which established general procedures to be used by all agencies for developing policy , promulgating rules , notifying the public and other agencies of intended actions , requesting public information , disseminating information to the public , and receiving comments from the public and other agencies ( 5 u.s.c . 551 - 559 , 701 - 706 ) .
the apa recognized the right of the public to know about , contribute to , and monitor the actions of federal agencies , and it established the federal register as an official mechanism for information dissemination and solicitation . although the apa did not call for public involvement in the actual decision - making itself , it did create requirements and procedures for public participation in the information gathering and feedback phases of the process .
more than 20 years later , in 1969 , the national environmental policy act ( nepa ) required federal agencies to inform one another and the public about the expected environmental , economic , and social ramifications of their proposed actions . whereas the apa required agencies to make relevant documents available to the public , the nepa guaranteed access to public information and the right to be heard before the final decision was made . in 1970 ,
president richard m. nixon issued executive order 11514 ( march 7 , 1970 , 35 f.r .
4247 ) , which increased the public notice requirements established by nepa so that federal agencies were required to develop procedures to ensure the fullest practicable provision of timely public information and understanding of federal plans and programs with environmental impact in order to obtain the views of interested parties .
the 1970s saw increased support for public participation in environmental assessment and decision making . the federal advisory committee act ( faca ) of 1972 mandated standards and procedures to assure that federal advisory committees served public rather than private interests , and required that committee composition fairly balance competing viewpoints and biases . in 1978 ,
the council on environmental quality ( ceq ) expanded nepa requirements by compelling federal agencies to ascertain which issues the public believed were important as part of the initial scoping process for environmental impact assessments . today
, federal agencies have significant latitude in determining who to involve in environmental decision making , when they are involved , the type and intensity of involvement , the influence of public participation on the final decision , and the goals of the participation process .
officially sanctioned processes and procedures for public participation typically aim to achieve one or more of six main objectives : i ) improve the quality of decision output ; ii ) represent values and preferences in proportion to their prevalence in the affected population ; iii ) encourage competition of arguments with respect to criteria of truth , normative validity , and truthfulness ; iv ) use common sense as the final arbiter in disputes , e.g. , the jury model ; v ) empower less privileged groups and individuals ; and vi ) demonstrate the variability , plurality , and legitimacy of dissent .
nevertheless , concerns remain that public participation might damage the decision - making process through unintended consequences and increased transaction costs .
criticisms generally fall into four main categories : i ) public participation may descend into political manipulation ; ii ) public participation may impair decision quality , particularly the use of scientific evidence ; iii ) public participation does not necessarily guarantee fairness and equity ; and iv ) public participation may produce trivial or undesirable results at substantial costs .
so , while there is general agreement that people whose lives are affected should have a say in environmental health decisions , there is still considerable debate about how best to integrate values and judgment into the science - based process of assessing and managing risks .
since publication of the nrc s red book in 1983 , four major trends in the evolution of the ra - rm paradigm are evident .
first , a consensus has emerged that it is important at the outset to develop a shared understanding of the context , formulation , and scope of the problem being addressed , including concurrence among participants about a suitable risk management approach .
second , it is now widely accepted that socioeconomically and politically disadvantaged communities , many of whom are ethnic and racial minorities , are likely to be more vulnerable to the adverse effects of environmental stressors because they tend to be both more exposed and more susceptible than the general population .
third , there is broad - based agreement among both experts and stakeholders that the domain of risk assessment must expand beyond single chemicals , individual emission sources , and specific exposure pathways and routes to encompass combined health effects from exposures to multiple chemical and non - chemical stressors via all relevant modes of exposure . and fourth
, public participation is now an explicit and intrinsic part of epa s process for assessing and managing environmental health risks .
the progression of public participation in the ra - rm paradigm can be traced through a series of influential public - sector reports that document its increasingly pivotal role over the past 30 years . in the nrc s red book ,
the emphasis was on establishing the basic four - step framework ( i.e. , hazard identification , dose - response assessment , exposure assessment , risk characterization ) for risk assessment and clarifying the interconnected and mutually supportive relationships among scientific research , risk assessment and risk management in the decision - making process .
as shown in figure 1 , the nrc did not include public participation as an explicit component of the ra - rm paradigm . the report deemed public concern to be an external pressure and recommended that detailed guidelines setting forth the scientific and policy bases of risk assessment could improve public understanding and help dispel the impression that government actions are based on tenuous and inadequate reasoning .
the nrc noted that public perceptions of risk and risk - based decisions could be inaccurate and inappropriate if government agencies do not provide suitable and timely information to the interested parties .
the nrc further recommended that before an agency decides whether a substance should or should not be regulated as a health hazard , a detailed and comprehensive written risk assessment should be prepared and made publicly available .
this written assessment should clearly distinguish between the scientific basis and the policy basis for the agencys conclusions .
they went on to say that the written assessment should be made accessible to the public at a time and in a form that facilitates public participation in any attendant risk management decision .
this is the first mention by the nrc of the need for public participation in the ra - rm paradigm .
eleven years later in 1994 , the nrc published a reappraisal of the ra - rm paradigm , titled science and judgment in risk assessment .
although the report focused primarily on risk assessment practices and strategies for improving them , it noted that the ra - rm paradigm had come under increasing criticism pertaining to both the conduct of risk assessments and the relationship between risk assessment and risk management .
the committee affirmed that social and cultural factors were important and might alter risk management priorities when taken into account .
they also observed that people s perceptions of environmental health risks do not necessarily match those of technical experts , and that public opinion about the need for regulations is influenced by factors such as trust in government , experience with expert judgments , and attitudes about social justice . among the committee
s recommendations was for epa to fully communicate to the public each risk estimate , the uncertainty in the risk estimates , and the degree of protection .
however , no changes related to public participation in the ra - rm paradigm were proposed .
the nrc report understanding risk : informing decisions in a democratic society was released in 1996 . in it
the nrc proposed reinterpreting risk characterization as a combination of analytical and deliberative processes that would increase the likelihood of achieving sound and acceptable risk - based decisions ( figure 2 ) .
the committee identified broad public participation by interested and affected parties as one of the essential aspects of this change , and listed three fundamental reasons for involving the public in the ra - rm paradigm ; i ) it is consistent with the principle that government should obtain the consent of the governed ; ii ) risk - related wisdom is not limited to scientific specialists and public officials , which suggests that participation by diverse groups and individuals will interject new information and practical insights into the decision - making process ; and iii ) meaningful participation by a broad - based constituency is likely to increase acceptance and build trust in risk - related decisions .
the committee felt that deliberations about risk characterization should occur prior to any agency proposals or actions , and that they should be aimed at improving mutual understanding of risk situations through collaborative exchanges in which public officials , risk experts , and key stakeholders share information and ideas while interacting as equals . in 1997 , the presidential / congressional commission on risk assessment and risk management ( pccrarm ) published its report framework for environmental health risk management , which introduced a new conceptual process for managing environmental health risks .
the commission defined a six - stage procedure for making good risk management decisions : i ) define the problem ; ii ) analyze risks associated with the problem in context ; iii ) examine options for addressing the risks ; iv ) make decisions about which options to implement ; v ) take action to implement the decisions ; and vi ) conduct an evaluation of the actions .
all six phases were to be conducted in collaboration with stakeholders as active partners so that different technical perspectives , public values and perceptions , and community ethics are considered ( figure 3 ) .
recommendations were made to establish a process for engaging stakeholders , and a set of guidelines for stakeholder involvement was proposed ( table 1 ) .
the pccrarm listed seven benefits of involving stakeholders in the risk management process : supports democratic decision - making ; ensures that public values are considered ; develops the understanding needed to make better decisions ; improves the knowledge base for decision - making ; reduces overall time and expense of decision - making ; improves the credibility of agencies responsible for managing risks ; and fosters risk management decisions that are better accepted and more readily implemented .
the nrc s science and decisions : advancing risk assessment , also known as the silver book , was published in 2009 .
it provided a scientific and technical review of current risk - analysis concepts and practices at the epa and offered recommendations for practical improvements .
the committee proposed that the ra - rm paradigm first established in 1983 be modified to include three distinct phases : phase 1 , problem formulation and scoping ; phase 2 , planning and conduct of risk assessment ; phase 3 , risk management ( figure 4 ) .
formal provisions were to be made for internal and external stakeholder involvement in all three phases because the committee recognized that greater stakeholder involvement is necessary to ensure that the process is transparent and the risk - based decision - making proceeds effectively , efficiently , and credibly .
the nrc recommended that epa should establish a formal process for stakeholder involvement in the framework for risk - based decision - making with time limits to ensure that decision - making schedules are met and with incentives to allow for balanced participation of stakeholders , including impacted communities and less advantaged stakeholders .
the nrc committee observed that without meaningful stakeholder involvement , there is no way to assure that risk - based decision - making will be satisfactory and , in fact , that decisions will be unavoidably incomplete in the absence of such involvement .
they went on to point out that the box representing stakeholder involvement at the bottom of figure 4 spans all three phases of the ra - rm paradigm , and that the two - headed arrows are meant to represent the necessity of two - way communication .
the committee opined that adequate stakeholder involvement and communication among those involved in the policy and technical evaluations are difficult to achieve , but they are necessary for success .
it is time that formal processes be established to ensure implementation of effective stakeholder participation in all stages of risk assessment .
over the past three decades , the role of public participation has expanded from being only a peripheral concern labeled as an external pressure in the 1983 red book , to being formally incorporated into the ra - rm paradigm in the 2009 silver book .
it is now the nrc s position that stakeholder involvement needs to be an integral part of all phases of risk - based decision making , including problem formulation and scoping , planning and conduct of risk assessments , and decisions about risk management options .
most observers and participants agree that affected parties , including members of impacted communities , representatives of ngos , business people , and interested citizens , should join with regulatory officials to evaluate threats from environmental hazards , make mutually acceptable risk management decisions and jointly solve environmental problems . while the costs and benefits of involving stakeholders in the decision - making process vary according to situations and circumstances , it has become evident that public participation offers three major benefits : i ) it promotes stakeholder buy in , which is vital for ensuring public acceptance of risk - based decisions ; ii ) it taps into unique stakeholder knowledge of the local situation , which can complement specialized knowledge of scientists and risk assessors ; and iii ) it promotes the concept of environmental democracy , an important social value , by treating stakeholders as equals in decision - making .
public participation in risk - based decision making is not a politically correct fad that will fade as new issues and ideas become fashionable .
the idea of meaningfully involving interested and affected parties in all aspects of environmental health decisions is indorsed by the nrc and incorporated into official epa policy .
moreover , environmental policy in the united states continues to undergo a transition from the partially successful but increasingly outdated pollution control strategies of the 20 century to new and innovative 21 century approaches that offer greater environmental improvements at less cost ( table 2 ) .
stakeholder involvement in collaborative coalitions and partnerships aimed at finding cooperative resolutions to complex and contentious environmental health problems is a key element of the new 21 century regulatory strategy .
public participation and stakeholder involvement are central to this emerging policy landscape , which emphasizes finding common ground among diverse stakeholders in order to achieve cooperative and cost - effective solutions . on january 21 , 2009 ,
president barack h. obama issued a memorandum on transparency and open government , in which he said : my administration is committed to creating an unprecedented level of openness in government .
we will work together to ensure the public trust and establish a system of transparency , public participation , and collaboration . in the memorandum he enunciated three principles : i )
knowledge is widely dispersed in society , and public officials benefit from having access to that dispersed knowledge .
looking ahead , it seems clear that public participation will remain a vital and intrinsic feature of the ra - rm paradigm for the foreseeable future .
both advocates and critics alike agree that risk - based decisions should not be based solely on scientific and technical expertise , but ought to be refined and enhanced through stakeholder involvement and public participation . to the extent that interested and affected parties are involved meaningfully in risk - based decision making , both the process and the product
what lessons can we draw from the u.s . experience with public participation in the ra - rm paradigm ? first , it is apparent that a private , nonprofit , self - perpetuating society of distinguished scholars , like the national academy of sciences ( nas ) , whose function is to provide independent advice to the federal government on scientific and technical matters , can serve a pivotal role in evaluating the ra - rm paradigm and recommending needed modifications . the scientific stature and respect accorded the nas ensures that its recommendations are publicized and taken seriously ; often acting as catalysts for action .
second , as experience is gained with ever more complex and costly - to - solve environmental health risks , it often becomes necessary to adapt and modify various aspects of the ra - rm paradigm to accommodate newly recognized and/or recently redefined problems .
third , a general consensus has emerged that public participation is usually desirable and that it constitutes a worthwhile goal ; sentiments which have caused it to be incorporated formally into the ra - rm paradigm .
fourth , although participation is embraced in principle , in practice questions remain about appropriate procedures and processes for successful implementation . and
fifth , evolution of the ra - rm paradigm , including the expanding role of public participation , tends to reflect adjustments and alterations in environmental health policy as the u.s .
transitions from a more adversarial pollution control system to one that is more of a collaborative partnership among government , industry , and stakeholders . but the escalating role of public participation in the ra - rm paradigm raises at least as many questions as it answers . among the more important are the following : i ) do present - day methods for risk assessment and risk management include adequate mechanisms for involving the public meaningfully in risk - based decision making ?
ii ) to what extent are different forms and degrees of public participation applicable to specific risk - based situations and circumstances ?
iii ) what are the relative transaction costs and opportunity costs associated with different forms of public involvement ?
iv ) are there practical limits to the value of public participation for risk - based decision making and , if so , what are they ?
v ) how do the political and policy contexts within which the ra - rm paradigm is rooted affect the form and function of public participation ?
vi ) how do social mores and cultural values affect the conceptual configuration of the ra - rm paradigm and the role of public participation within that framework ?
vii ) does increasing public involvement in risk - based decisions make them more likely to be accepted by the general public as well as affected communities and populations ?
viii ) does public participation ( in whatever guise ) as part of the ra - rm paradigm lead to better risk - based decisions where better means more effective , efficient , and equitable ?
ultimately , targeted research is needed to answer these and related questions so that we can make informed choices about adjustments to the ra - rm process that will encourage improved decisions about protecting environmental quality and safeguarding human health .
Output:
| significance for public healthrisk - based decision making is a core feature of government actions aimed at protecting public health from the adverse effects of environmental hazards . in the past
, it has often been an expert - driven , mostly obscure process used by federal agencies to justify and defend regulatory decisions made outside the public arena .
but the nature of decision making has changed as it has become apparent that environmental health problems are more complicated , controversial , and costly to solve than originally thought .
meaningful public engagement is now an inherent component of all phases of the risk assessment risk management paradigm because it promotes stakeholder buy in , taps into unique stakeholder knowledge , and promotes the concept of environmental democracy.in the united states , the risk assessment risk management paradigm that underpins federal decisions about environmental health risks was first established in 1983 . in the beginning ,
the importance of public participation was not explicitly recognized within the paradigm . over time , however , it has become evident that not only must risk - based decisions be founded on the best available scientific knowledge and understanding , but also that they must take account of the knowledge , values , and preferences of interested and affected parties , including community members , business people , and environmental advocates .
this article examines the gradually expanding role of public participation in risk - based decision making in the united states , and traces its evolution from a peripheral issue labeled as an external pressure to an integral element of the 21st century risk assessment risk management paradigm .
today , and into the foreseeable future , public participation and stakeholder involvement are intrinsic features of the emerging american regulatory landscape , which emphasizes collaborative approaches for achieving cooperative and cost - effective solutions to complicated and often controversial environmental health problems . |
PubmedSumm118734 | ***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: chemical sensing using
surface - enhanced raman spectroscopy ( sers )
has recently exploded in popularity as wet chemical nanosynthesis
techniques , especially related to surface control , have evolved . a technique called layer - by - layer
( lbl ) polyelectrolyte wrapping
has been used in recent years for a diverse set of surface control
applications ranging from drug delivery , biomimetic sensors , and biofilms for
medical implants .
lbl offers multiple
advantages in terms of practical sensing including facile , precise ,
and robust control over nanoparticle surface chemistry . with lbl ,
it is straightforward to modify the surface chemistry and charge of
hydrophilic nanoparticles with the incubation of polyelectrolyte - containing
solutions with minimal preparation
. nanoparticles
are easily functionalized with reactive moieties and reacted with
biomolecules or fluorescent tags for sensing applications .
additionally ,
lbl - wrapped nanoparticles resist aggregation in both polar and nonpolar
solvents through steric effects , making them a valuable tool for improving
colloidal nanoparticle stability .
lbl
wrapping is a major advance in terms of nanomaterial surface control
and will continue to be an important tool for biological sensing due
to the chemical and optical complexity of the tissue microenvironment .
the incorporation of specific optical reporter molecules into plasmonic
nanostructures is necessary to accomplish sers sensing .
optical reporter
molecules typically consist of fluorophores or other heavily conjugated
molecules with delocalized -electrons electrostatically bound
near the nanoparticle surface .
encapsulation of reporter molecules
is necessary upon exposure to harsh ionic environments or biological
systems where the molecules are likely to leach into the environment .
the most popular technique involves the encapsulation of raman - active
molecules into silica layers grown around metallic nanoparticles .
this process is based off the stber method in which silica
is formed via the condensation of tetraethyl orthosilicate ( teos )
or sodium silicate onto a nanoparticle surface bearing poly(ethylene
glycol ) ( peg ) or silane ligands . while silica is effective
at molecular encapsulation , its growth is prone to variability , requires
organic solvents , and is time - consuming . furthermore , it is difficult
to spatially localize vitrified molecules with respect to their distance
from the metallic surface , which is a critical factor in determining
sers activity .
lbl encapsulation of reporter molecules is an
emerging technique
that addresses many crucial aspects in the design of sers nanoprobes .
in this technique ,
reporter molecules are electrostatically bound
to an oppositely charged polyelectrolyte wrapped around the nanoparticle
surface . after a short incubation period ,
additional layers of polyelectrolyte
may be wrapped around the nanoparticle , effectively trapping the reporter
molecule in a soft template of polymer .
lbl wrapping , in contrast
to silica coating , is straightforward and reproducible and requires
minimal characterization during the wrapping stages .
design flexibility
involving factors such as porosity , coating density , and conformation
of the bound polyelectrolyte is possible through tuning the ph , salt
concentration , molecular weight of the polyelectrolyte , and electrolytic
strength .
furthermore , each polyelectrolyte multilayer adds an additional
thickness of 1.5 nm , from which it is possible to approximately
localize the trapped molecules .
we have
previously demonstrated this technique , illustrating
its robustness as a preparation method for sers nanoprobes . in this study , we investigated the long - term storage and stability
of sers nanoprobes in the form of polyelectrolyte - wrapped gold nanoparticles .
predicting and understanding the sers signal intensity over long periods
of time under a variety of environmental conditions is essential for
the design of sers nanoprobes intended for biological sensing applications .
numerous reports investigating the formation and control over layer
deposition of polyelectrolyte multilayers have yet to explore the
signal stability of polyelectrolyte encapsulated reporter molecules .
unlike drug delivery studies with intentionally porous or degradable
films , sers nanoprobes are designed to maintain their structure and
chemical signature over an indefinite period of time without noticeable
signal loss .
we maximized the reproducibility of our measurements
and mimicked the optical environmental conditions of a tissue - based
measurement by performing all raman measurements in - suspension with
near - infrared laser excitation .
suspension - based measurements within a finite path length cuvette
ensured proper accounting for the anticipated optical effects between
sers and light extinction in tissue measurements .
nanoprobe stability was investigated by storing aliquoted samples
at 4 c , room temperature , and physiological temperature ( 37
c ) for a period of 5 weeks .
to further
investigate the stability and lifetime of our nanoprobes , we also
studied chemically cross - linked polyelectrolyte layers and thiolated
molecules .
cetyltrimethylammonium
bromide ( ctab , > 99% ) ,
sodium borohydride ( nabh4 , > 99.99% ) , 15 000
g / mol poly(acrylic acid , sodium salt ) ( paa ) , 15 000
g / mol poly(allylamine hydrochloride ) ( pah ) , 5,5-dithiobis(2-nitrobenzoic
acid ) ( dtnb , > 98% ) , ascorbic acid ( > 99% ) , 5000 g / mol methyl
ether
poly(ethylene glycol ) thiol ( mpeg - sh ) , glutaraldehyde ( em grade 8%
in h2o ) , bovine serum albumin ( bsa , > 96% ) , and methylene
blue ( mb , > 82% ) were purchased from sigma - aldrich and used without
further purification .
all glassware were cleaned with aqua regia ( 3:1
hcl : hno3 ) and rinsed multiple times with 18 m cm
water .
holey carbon transmission electron
micrograph ( tem ) sample grids were purchased from pacific grid - tech .
the size distribution was verified by examining at least 100
particles per grid using imagej analysis software .
centrifugation was performed using a thermo scientific sorvall legend
x1 centrifuge with a swinging bucket configuration .
raman spectra were measured using
a horiba labram confocal raman microscope with the laser line configured
to an excitation wavelength of 785 nm .
all measurements were performed
in solution with a 1 cm path length quartz cuvette and an incident
power of 14 mw in reflection .
integration time was varied
between 10 and 20 s , depending on the concentration of individual
nanoparticle solutions , with a spectral resolution of 10 cm .
samples were stored at 4 c , room temperature ( 22
c ) , or 37 c .
all samples were allowed to equilibrate to
room temperature before raman measurements were performed .
gold nanospheres were first prepared
by synthesizing seed using a modified protocol intended for nanocube
synthesis . under vigorous magnetic stirring
0.25 ml of haucl4 ( 0.01 m ) and 7.5 ml of ctab ( 0.1 m ) were
mixed . to this solution , 0.6 ml of freshly prepared , ice - cold ( 0.01
m ) nabh4 was added .
the seed was kept at room temperature for a
minimum of 1 h to fully hydrolyze any remaining nabh4 .
gold nanospheres were synthesized in 40 ml batches consisting of 6.4
ml of ctab ( 0.1 m ) , 0.8 ml of haucl4 ( 0.01 m ) , and 32 ml
of h2o . to this solution , 3.8 ml of ascorbic acid ( 0.1
m ) was added and turned the solution colorless .
centrifugation was performed twice at
5000 g for 60 min to remove excess surfactant .
aqueous stock solutions
of paa and pah were prepared at a concentration
of 10 mg / ml ( containing 1 mm nacl ) . to 30 ml of gold nanospheres ,
at the as - synthesized concentration ,
6 ml of paa or pah stock was
added along with 3 ml of 10 mm nacl . to the first layer of paa
, 500
l of 1 mm methylene blue ( dissolved in methanol ) was added
and allowed to complex for 1 h. after each step , the nanoparticle
solutions were centrifuged at 3000 g for 1 h to remove
excess reagents .
the bsa layer was formed by adding 500 l of
1 wt % bsa to the suspension and allowing it to react for 2 h at room
temperature .
this corresponds to a 2000 molar excess
of bsa to nanoparticles . immediately afterward ,
the solution was dialyzed
in 4 l of water with a 100 000 g / mol membrane for 48 h. the
water was changed multiple times to ensure complete removal of unbound
reagents .
a highly concentrated stock solution was made such that
aliquots were taken and diluted into the appropriate buffer for each
experiment .
paa and pah layers have weak raman scattering cross sections
as compared to methylene blue ( figure s1 ) .
all samples were stored in 15 ml polypropylene conical tubes pretreated
with 1 wt % bsa solution to minimize sticking of nanoparticles to
the tube .
measurements were performed in triplicate and each solution
was adjusted to a concentration of 0.15 nm . to 40 ml of as - synthesized
gold nanospheres ,
5 ml of 1 mm mpeg - sh was added dropwise and under
sonication . immediately following mpeg - sh addition 2 ml of 1
note that the dtnb was adjusted to a ph 77.4 to
facilitate water solubility .
the solution was allowed to complex overnight
and then centrifuged at 4200 g for 1 h. the supernatant
was discarded , and the pellet was resuspended to 3 ml and 500 l
of 1 wt % bsa was added .
dialysis with a 100 000 g / mol membrane
was performed in 4 l of water over 48 h. twice purified gold nanospheres were
diluted to a volume of 30 ml .
6 ml of paa solution was added along
with 3 ml of 10 mm nacl and allowed to sit for 1 h. the solution was
then centrifuged at 4800 g for 1 h. following purification
of paa , 1 ml of 750 m of methylene blue ( in methanol ) was added .
after 1 h , the solution was centrifuged at 4800 g for
1 h to remove excess dye .
the solution was suspended in 30 ml of h2o , and 6 ml of pah stock was added with 3 ml of 10 mm nacl .
finally the solution was centrifuged again at 4000 g for 1 h and resuspended in h2o to obtain an optical density
of 4
. 1 ml of 8% glutaraldehyde was added and allowed to react for
2 h at 4 c .
purification was performed against a 3500 g / mol
dialysis membrane for 48 h in 4
raman measurements were performed on aliquots of this solution at
a concentration of 0.25 nm .
finite element method
calculations were performed using comsol multiphysics v4.3b with the
rf and chemical reaction engineering modules .
diffusion of methylene
blue through polyelectrolyte layers was modeled with an impermeable
boundary around a gold core of diameter 40 nm . a spherical shell 5
nm thick coated the gold core to represent the ctab and paa layer .
methylene blue was assumed to have a 2 nm thick layer with a uniform
distribution equating to 3000 molecules based off our previously experimental
work .
a 5 nm shell surrounded the methylene
blue layer to account for the paa / pah / bsa layers .
( a ) schematic
of prepared gold nanospheres with alternating layers
of paa ( light blue shell ) , pah ( red shell ) , and methylene blue ( blue
stars ) . to prevent aggregation in highly ionic solutions , bsa ( purple
circles ) was bound to the outer layer .
( b ) transmission electron micrograph
of gold nanospheres . scale bar : 50 nm .
( d ) electronic absorption
spectra of ctab - stabilized gold nanospheres ( dotted line ) compared
to polyelectrolyte - wrapped nanospheres ( solid line ) .
sers nanoprobes were fabricated by wrapping alternating
layers
of weakly anionic poly(acrylic acid , sodium salt ) ( paa ) and cationic
poly(allylamine hydrochloride ) ( pah ) around gold nanospheres stabilized
with cetyltrimethylammonium bromide ( ctab ) surfactant .
as shown in
figure 1a , cationic optical reporter molecules
( methylene blue ) were encapsulated electrostatically between the first
layer of paa and subsequent layers of polyelectrolyte and bovine serum
albumin ( bsa ) .
protein - induced flocculation was prevented by wrapping
a final layer of paa around the nanostructure before the addition
of bsa .
bioconjugation studies typically use bsa to quench excess
reactive sites on antibody - conjugated nanoparticles as well as to
prevent nonspecific binding to sticky cell receptors in vitro . here
, bsa serves dual purposes ; first , bsa stabilizes
nanoparticles in highly ionic solutions such as phosphate buffered
saline , which is a common buffer used in cell culture and mimics the
environment found in tissue .
second , all nanoparticles exposed to
whole blood or serum will immediately develop a protein corona in
which proteins dynamically associate and dissociate from the surface .
researchers continue to intensely study the effects of the protein
corona both in vitro and in vivo as it can have significant unavoidable consequences on biocompatibility ,
renal clearance , and targeting capabilities .
the synthesized nanostructures were characterized with transmission
electron microscopy ( tem ) and -potential ( figure 1b , c ) . at room temperature all samples displayed stable electronic
absorption spectra for > 5 weeks ( figure 1d ) .
this robust method provides some design guidance in terms of the spatial
localization of the reporter molecules .
we anticipate that the reporter
molecules will be located approximately 4 nm from the metallic surface .
molecules obeying raman selection rules
exhibit enhancement through a combination of the commonly attributed
chemical and electromagnetic enhancement
effects of sers .
the electromagnetic enhancement effect is generally
regarded as the dominant mechanism , although this remains an active
area of research .
recently , le
ru and etchegoin discussed mathematical and interpretative errors
made in the first two reports on single - molecule sers where enhancement
factors ( efs ) of 10 were reported .
the propagation of these errors in comparison to fluorescence
cross sections resulted in numerous subsequent reports claiming similar
results . in many of these studies ,
the ef was empirically determined
from the following equation ef = ( nramanisers / nsersiraman ) , where nraman and iraman are the number
of molecules in the focal volume and its corresponding spontaneous
raman intensity .
likewise , nsers and isers correspond to the number of probed molecules
bound to the nanoparticles and their corresponding sers intensity .
based
on the calibration curve and sers intensity of each sample ( normalized
to incident laser power ) , an equivalent spontaneous raman signal may
be calculated .
the raman equivalent signal corresponds to the equivalent
concentration of mb molecules required to produce the same spontaneous
raman signal intensity as the probed solution . with this technique
top : sers spectra of
lbl - wrapped nanospheres : day 1 , black ; day
4 , red ; day 11 , blue ; day 18 , purple ; day 37 , green .
samples were
stored at ( a ) 22 , ( b ) 37 , and ( c ) 4 c .
bottom : predicted signal
intensity ( red line ) and the experimental spontaneous raman equivalent
signal quantified at the 1616 cm band .
all samples
were normalized to 0.15 nm . using a spontaneous raman quantification technique , we investigated
the signal stability of the nanoprobes described in figure 1 over the course of 5 weeks .
triplicate aliquots
of solutions were stored at room temperature ( 22 c ) ,
37 c , and 4 c . as shown in figure 2 , the spectral features tend to change and decay as time progresses
.
samples stored at 4 c , while having the largest variation in
signal , maintained their spectral shape better than samples stored
at warmer temperatures .
intuitively , the diffusion of molecules through
polyelectrolyte layers is expected to be linearly related to temperature ,
i.e. , analogous to the stokes einstein relationship .
after
5 weeks of storage , several samples were centrifuged to concentrate
the nanoparticles into pellets .
we calculated that a 3 ml solution
of 0.15 nm nanoparticles should release approximately 5 m of
reporter molecules .
the supernatant was extracted , and we found that
it did not contain a micromolar quantity of dye molecules , indicating
that a fraction of the methylene blue molecules were trapped away
from the metallic surface but not free in solution . to understand
this process and determine if diffusion can be ascribed as a major
cause of the loss of signal , we carried out modeling .
the first part
of our model involves the temporal prediction of the diffusion of
the reporter molecules through the polyelectrolyte layers .
the second
part relates the concentration to the electromagnetic enhancement
factor , thereby producing a total predicted intensity .
( a ) concentration profile
as a function of time with a diffusion
coefficient of d = 10 cm / s . ( b ) calculated electromagnetic enhancement factor ( ef )
for a 40 nm gold nanosphere as a function of distance from the surface .
inset : gold nanosphere illustrating a dipolar plasmon resonance ( scale
bar 20 nm ) .
( d ) predicted
signal intensity s(t ) . neglecting the effects of concentration due to
the low loading
and charge , diffusion through polyelectrolyte layers
was assumed to
be constant and modeled using fick s second law of diffusion
( figure 3a):1where d is the diffusion
coefficient and c is the concentration as a function
of position , x , and time , t. equation 1 was solved using the finite element method with
an impermeable boundary condition at the surface of the gold core ,
a uniform distribution of methylene blue , and an enforced concentration
of zero at the edge of the bsa water interface . the latter
boundary condition is justified as diffusion within the solution would
be much faster than diffusion in the polyelectrolyte layers .
mathematically ,
the boundary conditions may be stated as234where c0 corresponds
to the initial distribution of molecules uniformly positioned within
a 2 nm thick layer .
furthermore , the model conserved flux across these
three regions : c1/x = c2/x and c2/x = c3/x with a fixed coefficient k = c1/c2 = c2/c3 = 0.9 the diffusion coefficient
was determined by simulating concentration versus time with a range
of values from d = 10 to 6
10 cm / s ( figure
s4 ) . after an approximate match was identified , the simulated
signal was compared to the experimental data ( figure 2 ) to further optimize the result .
we found that a diffusion
coefficient of d = 10 cm / s provided the most appropriate fit .
it should be noted that
the value of d is calculated under the assumption
of specific boundary conditions , i.e. , zero concentration at the particle
boundary .
it is likely that some methylene blue is trapped within
the particle and at its surface , resulting in a smaller concentration
gradient than the one assumed in our model that would lead to a lower
value of d being estimated . under these constraints ,
the value of d should be used to impute a loss of
signal rather than a loss of concentration .
the second portion
of our model incorporates the ability of a plasmonic
nanoparticle to surface - enhance the chemical signature of nearby molecules
from the metallic surface . for a spherical plasmonic nanosphere , a
dipolar evanescent electric field
the local electric field eloc dictates the degree of enhancement approximately by |eloc| . under the assumption of a quasi - static
electric field ,
a nanoparticle s enhancement factor ( ef ) decays
as ef 1/(a + d ) , where a is the radius of the nanoparticle and d is the distance of the molecule from the surface ( figure 3b ) .
the product of enhancement
and concentration is shown in figure 3c as
a function of time .
the predicted signal , s(t ) , was calculated by the following ( figure 3d):5reporter molecules are predicted
to diffuse
both toward and away from the metallic core . as a result
, signal intensity
is bolstered by molecules diffusing closer to the nanoparticle surface .
the diffusion coefficient was empirically determined from our data .
in a previous study , chung and rubner
experimentally determined the
diffusion coefficient for methylene blue in alternating layers of
paa and pah on substrates to be on the order of 1010 cm / s , depending on ph
and buffer conditions .
klitzing and mhwald
recorded a diffusion coefficient on the order of 10 cm / s for the diffusion of rhodamine through polyelectrolyte
films . in our case ,
numerous factors could
contribute to the discrepancy including the presence of a negatively
charged outer bsa layer , ionic strength , buffer conditions , or the
binding affinity of polyelectrolyte layers around gold nanoparticles
versus glass substrates .
it should also be noted that there have been
some reports describing the non - fickian behavior of small molecule
diffusion through polyelectrolytes as a result of swelling and electrostatic
effects .
typically , the design of sers nanoprobes
using encapsulation methods
seek to minimize diffusion . while simple encapsulation in a multilayer
system can be a facile route , it results in a limited shelf life due
to these effects .
hence , we explored a strategy to reduce diffusion
by gelling the outermost polymer layer and imparting much greater
stability to the nanoprobe s sers intensity over long periods
of time .
aliphatic amines from the pah layer were chemically
cross - linked and stored at 4 c to help prevent diffusion .
day 1 ,
black ; day 6 , red ; day 12 , blue ; day 17 , purple ; day 22 , green ; day
31 , gray .
( b ) quantification of sers intensity in terms of equivalent
spontaneous raman signal of methylene blue .
chemical cross - linking was investigated as a method for minimizing
undesirable diffusion of optical reporter molecules ( figure 4 ) .
an amine reactive cross - linker ( glutaraldehyde )
was added in molar excess to a solution consisting of lbl - encapsulated
nanostructures ( paa + mb + pah ) .
we observed that after
a 2 h incubation period lbl glutaraldehyde nanoparticles were stable
and did not show signs of aggregation as measured by electronic absorption
spectroscopy . in figure 4 , we show that cross - linked
nanoparticles are significantly less susceptible to diffusion - dominated
signal loss .
furthermore , cross - linked samples stored at 4 c
were more stable than samples stored at room temperature ( figure s5 ) .
cross - linking of the outer
polyelectrolyte layer likely improves
the outer shell stability of the nanoparticle and decreases pore size
such that the reporter molecules do not as readily diffuse .
dls was
used to verify the size distribution after multiple weeks of storage
( figure s6 ) .
the porosity and conformation
of polyelectrolyte layers bound to gold nanoparticles are difficult
to ascertain due to inherent variability in individual nanoparticles
and the sheer quantity of particles in solution .
to date , polyelectrolyte - based
studies have focused on the characterization of polyelectrolyte multilayer
thin films bound to substrates .
researchers have shown results demonstrating
that changes in a solution s ph can affect porosity .
in fact ,
when washing with acidic solutions ( ph = 2.4 ) , the porosity of paa / pah
films is greatly increased .
it has also
been demonstrated that exposure of paa / pah films to pure water can
increase the surface roughness of bound polyelectrolytes . by exploiting tunability in porosity , it may
also be possible to design versatile drug delivery systems . in addition
to porosity , the diffusive properties of polyelectrolyte - wrapped nanoparticles
has led to their use as drug delivery platforms , where
control of the diffusion of small molecules is desirable .
our experimental
and theoretical results indicate diffusive - like behavior in polyelectrolyte
multilayers , which is necessary for tuning the release profile in
terms of drug delivery and is , of course , likely to be crucial in
the design of multifunctional theranostic particles .
( a ) schematic of 5-thionitrobenzoic
acid ( orange shell ) and methyl
ether poly(ethylene glycol ) thiol ( tnb - peg ) coated nanoparticles with
adsorbed bsa ( purple spheres ) .
( c ) representative raman spectra of tnb - peg
coated nanoparticle : day 1 , black ; day 4 , red ; day 11 , blue ; day 16 ,
purple ; day 26 , green ; day 42 , gray .
( d ) spontaneous raman equivalent
of tnb - peg nanoparticles in terms of mm of dtnb .
while the previous discussion has focused on nanoprobes that
were
electrostatically trapped by lbl assembly , another route to effective
sers sensing is by way of passivating optical reporter molecules at
the surface of the nanoparticle .
thiolated molecules were used to
investigate the stability of nondiffusive , covalently bound raman
molecules .
thiol has a strong affinity for metals such as gold and
forms a covalent gold
thiolate bond . to investigate signal stability , we used ellman s reagent
or 5,5-dithiobis(2-nitrobenzoic acid ) ( dtnb ) , which has a
strong symmetric no2 stretch at 1333 cm . upon reduction ,
the disulfide bond
readily cleaves into two 5-thionitrobenzoic acid ( tnb ) molecules .
nanoprobes were prepared with a mixed layer of methyl ether poly(ethylene
glycol ) thiol ( mpeg - sh ) and tnb ( figure 5a ) .
a layer of bsa was adsorbed to the outermost layer to mimic the polyelectrolyte
configuration .
the -potential measurements verified that each
synthetic step was successful ( figure 5b ) .
samples were prepared in triplicate and stored at identical temperatures
as the polyelectrolyte - wrapped nanoparticles .
figure 5c shows representative raman spectra ( normalized to laser
power ) of tnb - peg coated nanoparticles stored for more than 5 weeks
at room temperature . throughout the storage period
spontaneous raman equivalents ( figure 5d ) were computed using a spontaneous raman calibration
curve of aqueous dtnb ( ranging from 5 to 15 mm ) with an adjusted ph
of 7 ( figure s3 ) . because of the strength
of the gold thiolate bond , tnb - peg coated nanoparticles were
less susceptible to signal loss over time .
as expected , the storage
considerations for thiolated raman reporters are less crucial than
lbl nanostructures .
careful consideration
of electrostatically encapsulated optical
reporter molecules for sers nanoprobes is critical . in this study ,
we investigated the signal stability of sers nanoprobes using polyelectrolyte
lbl wrapping to encapsulate reporter molecules .
we found that polyelectrolyte - wrapped
samples stored at colder temperatures ( 4 c ) are more likely
to maintain their spectral signature .
samples stored at room temperature
and 37 c were more likely to exhibit strong diffusion effects
over the course of 5 weeks . a diffusion coefficient of 10 cm / s was derived by fitting our experimental data to
a diffusion / electromagnetic enhancement model .
to overcome signal
degradation of sers nanoprobes , chemical cross - linking of a polyelectrolyte - wrapped
nanoparticle is sufficient .
we find that storage of cross - linked samples
at 4 c is best for long - term usage .
thiolate bonds also prevent reporter molecule
diffusion ; however , thiolated molecules are typically limited in availability
and expensive .
Output:
| the popularity of nanotechnology - based
sensing technologies has
rapidly expanded within the past decade .
surface - enhanced raman spectroscopy
( sers ) is one such technique capable of chemically specific and highly
sensitive measurements .
the careful preparation of sers - active nanoprobes
is immensely vital for biological applications where nanoprobes are
exposed to harsh ionic and protein rich microenvironments .
encapsulation
of optical reporter molecules via layer - by - layer ( lbl ) polyelectrolyte
wrapping is an emerging technique that also permits facile modification
of surface chemistry and charge .
lbl wrapping can be performed within
a few hours and does not require the use of organic solvents or hazardous
silanes .
nonetheless , the stability of its products requires further
characterization and analysis . in this study ,
raman - active methylene
blue molecules were electrostatically encapsulated within alternating
layers of cationic and anionic polyelectrolytes surrounding gold nanospheres .
we observed molecular diffusion of methylene blue through polyelectrolyte
layers by monitoring the change in sers intensity over a period of
more than 5 weeks . to minimize diffusion and improve the long - term
storage stability of our nanoprobes , two additional nanoprobe preparation
techniques
were performed : thiol coating and cross - linking of the
outer polyelectrolyte layer . in both cases ,
molecular diffusion is
significantly diminished . |
PubmedSumm118735 | ***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: microsatellites , or simple sequence repeats ( ssrs ) , are repetitive stretches of a tandemly repeated motif of one to six base pairs , which has evolved and expanded owing to the replication slippage mechanism that is supposed to be the cause of their high polymorphic rates . recently , using a genome - wide alignment of two orzya species var .
indica and japonica , it has been demonstrated that the distribution of microsatellites is also influenced by the motif sequence and the sequence characteristics of the adjoining regions possessing the microsatellites , in addition to the replication slippage and point mutation model .
these repetitive stretches may occur in coding and in non - coding regions of the genome .
ssrs have been potentially designated as a class of co - dominant markers for evaluating germplasm , establishing phylogenetic and evolutionary relationships .
it has been observed that clusters of microsatellite motifs with moderate gc are abundant on chromosome number 2 in the model plant arabidopsis thaliana , which suggests that repetitive stretches may be biased towards the accumulation in a certain regions .
microsatellites have been associated with various functional roles such as their possible role in the regulation of promoters , transcription and translation , and these sequence repeats have been credited with evolutionary importance .
the positioning of microsatellites in the genome seems to play an important role in their regulatory activity ; hence , studying the distribution and understanding the possible reasons of microsatellites expansions across genomes have currently been the focus of current intense research .
organelle genomes , plant chloroplast and animal mitochondrial genomes have been referred to as natural counterparts .
features such as conserved gene order , lack of heteroplasmy ( occurrence of more than one type of organelle genome ) , low recombination rates and their relative small size are making these organelle genomes the widely used tools for phylogenetic studies . however , lack of heteroplasmy has not been universally observed in all the mitochondrial genomes and has been earlier potentially reviewed with the occurrence and factors affecting the stoichiometry of heteroplasmy in mitochondrial genomes of plants and animals .
the uniparental inheritance of the organelle markers provides a means to elucidate the genetic flow and genetic structure of the population and the organelle markers have been widely used in population studies ( for a review see provan et al . ) .
in silico development of ssrs of organelle genomes
has brought them up as potential markers for transferability among the species , ease of development and as key players in genome length variation .
they have been widely demonstrated as potential markers for establishing molecular evolutionary histories , demographic diversity and resolving phylogeny in a wide variety of species from pinus ( forest species ) to oryza sativa ( monocots ) .
there have been recent reports on the identification of perfect repeats in organelle genomes of various organisms .
however , previous studies have only been focused on a relatively small number of genomes and only perfect repeats have been identified . a proper characterization system that would allow researchers to search for the association of these repeats with
the coding or non - coding regions has been lacking in these reports . in the past few years
, systematic curated web repositories have been developed for the organelle genomes , which includes fugoid that displays the curated distribution of introns in organelle genomes with functional and structural data .
a database of universally published primer sequences of chloroplast genomes has been developed , providing a platform for studying molecular variations and evolution in chloroplasts .
these organelle genomes have been exploited further for the mining of genes , exons , introns , gene products , taxonomy , rna editing sites , snps and haplotype information , all of which are displayed as curated information in gobase . a comprehensive repository of unique proteins expressed in chloroplast proteome using liquid chromatography - mass spectrometry / mass spectrometry has been developed ( at_chloro ) , serving as a knowledge base to explore the envelope proteins .
however , a complete curated web - oriented integrated repository of repeat pattern is still lacking .
this has motivated us to undertake a genome - wide study and to develop a web - enabled interface to analyse the perfect and the imperfect repeats in organelle genomes .
we propose chloromitossrdb that offers a wide visualization of perfect and imperfect repeats across the chloroplast and mitochondrial genomes with corresponding genomic coordinates .
the aim of chloromitossrdb is to constitute a platform to access the utility of ssrs as markers for phylogenetic classification across species . to our knowledge , this is the first updated integrated repository of the genomic repeats in chloroplast and mitochondrial genomes accessible via web interface .
all the studied chloroplast ( 179 ) and mitochondrial ( 1982 ) genomes were retrieved from the national center for biotechnology information ( ncbi ) refseq database ( www.ncbi.nlm.nih.gov/ ) .
the required files such as gbk , fna , faa , gff and ptt were downloaded for the studied chloroplast and mitochondrial genomes and were stored as flat files sorted for each genome . for the identification of the perfect and imperfect repeats , the software tool imperfect microsatellite extractor ( imex ) has been used , which uses a sliding window algorithm to identify the regions with a repetitive stretch of a particular nucleotide motif either stretched perfectly or with levels of imperfection .
the algorithm allows the user to specify the minimal length of the consecutive nucleotide stretch and reports the ssr motif , motif repeat counts , coordinates of the ssrs tract in the genome and its location relative to coding and non - coding regions .
the association of the repeats in coding and intercoding regions was determined based on the sequence annotation information available in genbank database ( ncbi , www.ncbi.nlm.nih.gov ) .
we applied the following length criteria ( mono- , 12 ; di- , 6 ; tri- , 4 ; and for tetra- to hexa repeats , a minimum stretch of three minimum repetitions ) to define each ssrs as a true repeat . in case of imperfect repeats , the parameter for imperfection percentage ( p% )
all the studied chloroplast ( 179 ) and mitochondrial ( 1982 ) genomes were retrieved from the national center for biotechnology information ( ncbi ) refseq database ( www.ncbi.nlm.nih.gov/ ) .
the required files such as gbk , fna , faa , gff and ptt were downloaded for the studied chloroplast and mitochondrial genomes and were stored as flat files sorted for each genome . for the identification of the perfect and imperfect repeats , the software tool imperfect microsatellite extractor ( imex ) has been used , which uses a sliding window algorithm to identify the regions with a repetitive stretch of a particular nucleotide motif either stretched perfectly or with levels of imperfection .
the algorithm allows the user to specify the minimal length of the consecutive nucleotide stretch and reports the ssr motif , motif repeat counts , coordinates of the ssrs tract in the genome and its location relative to coding and non - coding regions .
the association of the repeats in coding and intercoding regions was determined based on the sequence annotation information available in genbank database ( ncbi , www.ncbi.nlm.nih.gov ) .
we applied the following length criteria ( mono- , 12 ; di- , 6 ; tri- , 4 ; and for tetra- to hexa repeats , a minimum stretch of three minimum repetitions ) to define each ssrs as a true repeat . in case of imperfect repeats , the parameter for imperfection percentage ( p% )
chloromitossrdb is hosted on a 32-bit linux server pre - installed with mysql ( http://www.mysql.com/ ) , apache ( http://www.apache.org/ ) and php ( http://www.php.net/ ) commonly called as lamp . a flow chart explaining the organization and
the work flow of the chloromitossrdb has been presented ( fig . 1 ) .
chloromitossrdb is based on a simple comprehensive relational database management system , mysql , that is sufficient for organizing , storing and retrieving the data with a single query .
the details of the relational mysql tables used in the construction of the chloromitossrdb database are explained in tables 1 and 2 .
table 1 shows the metadata for each genome , whereas the structure of the mysql relational tables depicting the repeat information stored for the coding and the non - coding regions is given in table 2 .
each query has been split into hierarchical levels of information that displays information on each genome ( e.g. accession , sequence length and nucleotide composition ) ( table 1 ) .
table 1.structure of the table chloromitometa that stores the meta - information of all the mitochondrial and chloroplast genomesinformationfielddata typekeyexampleaccession numberacc_noint(11)5881414 , 110189662sequence idseq_idvarchar(11)princ_000834 , ac_000022sequence nameseq_namevarchar(500)rattus norvegicus strain wistar mitochondrion , porphyra purpurea chloroplastsequence typeseq_typevarchar(50)complete genome , complete sequencesequence lengthseq_lengthint(11)16 613 bp , 7686 bpnucleotide composition of aa_perfloat33.06%nucleotide composition of tt_perfloat41.87%nucleotide composition of gg_perfloat13.58%nucleotide composition of cc_perfloat11.49%organelle typeorganellechar(1)m ( for mitochondrion ) , c ( chloroplast)taxon idtaxonint263 995
table 2.structure of the tables chloromitoperfectmicrosatellite and chloromitoimperfectmicrosatellite that store the repeat information of all perfect and imperfect microsatellites of mitochondrial and chloroplast genomesinformationfielddata typekeyexamplesequence idindex_novarchar(11)princ_000834 , ac_000022starting co - ordinate of ssrstartint(11)pri172 , 12843ending co - ordinate of ssrendint(11)pri182 , 12885motif ( repeating unit)motifvarchar(10)at , g , caacnumber of repetitionsiterationsint(5)3 , 7length of repeat tracttract_lengthint(11)12 bp , 18 bpnucleotide composition of aa_perfloat50.00%nucleotide composition of tt_perfloat0.00%nucleotide composition of gg_perfloat33.33%nucleotide composition of cc_perfloat16.67%repeat position informationcoding_infovarchar(50)coding ( if repeat is in the coding region ) or null ( if outside)protein i d ( if repeat in coding region)protein_idint(11)110189664 ( if repeat is in the coding region ) or 0 ( if non - coding)imperfection percentage of the tractimperfectionfloat9% , 0%alignment line 1alignment_line1textttaa - taattaaalignment line 2alignment_line2text * * * * * * * * * * * alignment line 3alignment_line3textttaattaattaathe last four columns ( imperfection , alignment_line1 , alignment_line2 and alignment_line3 ) are present only in the table that stores imperfect microsatellites ( chloromitoimperfectmicrosatellite ) .
figure 1.schematic illustration showing the flow of the organization of the data in chloromitossrdb .
structure of the table chloromitometa that stores the meta - information of all the mitochondrial and chloroplast genomes structure of the tables chloromitoperfectmicrosatellite and chloromitoimperfectmicrosatellite that store the repeat information of all perfect and imperfect microsatellites of mitochondrial and chloroplast genomes the last four columns ( imperfection , alignment_line1 , alignment_line2 and alignment_line3 ) are present only in the table that stores imperfect microsatellites ( chloromitoimperfectmicrosatellite ) .
the information for the genome composition ( a- , t- , g- and c- counts , etc
. ) has been computed from the flat files obtained from the ncbi refseq database ( table 1 ) .
the complete repeat information of the database is stored in two different tables ( refer table 2 ) , storing the perfect and imperfect repeats of all chloroplast and mitochondrial genomes .
the repeat information includes the details of individual repeats such as the sequence i d , start and end coordinates of the repeat , the repeating motif , number of iterations , total tract length , nucleotide composition of the repeat , protein information of coding repeats . in addition
, the table displaying the imperfect repeats also stores the imperfection percentage and alignment information that can be used to study the evolution of these repeats .
the complete browsing outlay of the chloromitossrdb is displayed ( fig . 2 ) .
the curated information is organized into several search patterns , and proper navigation pages have been provided .
the curated information from the imex has been processed further according to gene ids , organism name , and the ssrs were sorted according to the coding or non - coding regions .
the position of the coding regions has been determined using the annotated ptt files of each chloroplast and mitochondrial genome as downloaded from the ncbi refseq database .
this figure appears in colour in the online version of dna research . how to browse : schematic browsing of chloromitossrdb .
chloromitossrdb interface provides information on several repeat statistics , including the distribution of the repeat types , length of the motifs and their positions ( coding or non - coding repeats ) .
the querying of chloromitossrdb through the web interface is organized into three search patterns that accomplish all interface functionalities : query page , result page and report page : ( i ) the first search pattern is according to the organelle classification and it has been classified into chloroplast and mitochondrial genomes , ( ii ) the second search pattern has been classified according to the type of repeat pattern ( perfect or imperfect ) and ( iii ) .
the last search pattern allows the user to select the repeat size . with the appropriate selection pattern
, the user will be directed to the organelle - specific page ( chloroplast and mitochondrial ) containing the list of the organism for which the ssrs have been identified , which are further linked to the organism - specific repeat pages for further information on the distribution of the repetitive tracts . to ease the access of the database and to enhance the user functionality
, we also provide chloroplast and mitochondrial repeat - specific pages alphabetically ordered according to the organism name .
an advanced search option has been provided to filter the repeats based on the user - specific criteria allowing the user to search for a repeat region of a specific length .
an option to export the search results and the repeat information in excel format has been provided , so that the user can save and analyse the repeats , design primers and can utilize the information for further downstream processing of the observed repeats .
a query page for every organism is directed to a chloromitossrdb repeat summary page for organism - specific summary page that gives a detailed illustration of the distribution of the perfect and the imperfect repeats distribution and the genome composition using bar and pie charts . the genome composition and the repeat occurrence graphs
were generated dynamically based on the repeat information using libchart , a php chart drawing library ( http://naku.dohcrew.com/libchart/ ) .
the repeat pattern summary displayed on the organism specific page are clickable links , which redirects and give further information on the start and end of the ssr repeat containing tract , motif and the occurrence of the respective repeat pattern across the genomes .
mutations in the ssr stretches prevailing in the coding region may affect the subsequent transcription and translation of the gene harbouring the repetitive stretches of ssrs .
mutations in chloroplast ssrs ( mutation rates at cpssr loci as between 3.2 10 and 7.9 10 ) have been described as low when compared with substitution rates .
recently , it was observed that the plant mitochondrial substitution rates are relatively lower when compared with the invertebrates and mammalian mitochondrial genomes . to evaluate the distribution of the ssrs in the coding regions ,
the repeat - rich regions on the organism page have been linked to the corresponding protein ids ( ncbi , www.ncbi.nlm.nih.gov/ ) , in case of coding repeats , which can shed light on the evolution of these repeated regions either through mutational bias or through selective forces in further ongoing work .
chloromitossrdb is hosted on a 32-bit linux server pre - installed with mysql ( http://www.mysql.com/ ) , apache ( http://www.apache.org/ ) and php ( http://www.php.net/ ) commonly called as lamp . a flow chart explaining the organization and
the work flow of the chloromitossrdb has been presented ( fig . 1 ) .
chloromitossrdb is based on a simple comprehensive relational database management system , mysql , that is sufficient for organizing , storing and retrieving the data with a single query .
the details of the relational mysql tables used in the construction of the chloromitossrdb database are explained in tables 1 and 2 .
table 1 shows the metadata for each genome , whereas the structure of the mysql relational tables depicting the repeat information stored for the coding and the non - coding regions is given in table 2 .
each query has been split into hierarchical levels of information that displays information on each genome ( e.g. accession , sequence length and nucleotide composition ) ( table 1 ) .
table 1.structure of the table chloromitometa that stores the meta - information of all the mitochondrial and chloroplast genomesinformationfielddata typekeyexampleaccession numberacc_noint(11)5881414 , 110189662sequence idseq_idvarchar(11)princ_000834 , ac_000022sequence nameseq_namevarchar(500)rattus norvegicus strain wistar mitochondrion , porphyra purpurea chloroplastsequence typeseq_typevarchar(50)complete genome , complete sequencesequence lengthseq_lengthint(11)16 613 bp , 7686 bpnucleotide composition of aa_perfloat33.06%nucleotide composition of tt_perfloat41.87%nucleotide composition of gg_perfloat13.58%nucleotide composition of cc_perfloat11.49%organelle typeorganellechar(1)m ( for mitochondrion ) , c ( chloroplast)taxon idtaxonint263 995
table 2.structure of the tables chloromitoperfectmicrosatellite and chloromitoimperfectmicrosatellite that store the repeat information of all perfect and imperfect microsatellites of mitochondrial and chloroplast genomesinformationfielddata typekeyexamplesequence idindex_novarchar(11)princ_000834 , ac_000022starting co - ordinate of ssrstartint(11)pri172 , 12843ending co - ordinate of ssrendint(11)pri182 , 12885motif ( repeating unit)motifvarchar(10)at , g , caacnumber of repetitionsiterationsint(5)3 , 7length of repeat tracttract_lengthint(11)12 bp , 18 bpnucleotide composition of aa_perfloat50.00%nucleotide composition of tt_perfloat0.00%nucleotide composition of gg_perfloat33.33%nucleotide composition of cc_perfloat16.67%repeat position informationcoding_infovarchar(50)coding ( if repeat is in the coding region ) or null ( if outside)protein i d ( if repeat in coding region)protein_idint(11)110189664 ( if repeat is in the coding region ) or 0 ( if non - coding)imperfection percentage of the tractimperfectionfloat9% , 0%alignment line 1alignment_line1textttaa - taattaaalignment line 2alignment_line2text * * * * * * * * * * * alignment line 3alignment_line3textttaattaattaathe last four columns ( imperfection , alignment_line1 , alignment_line2 and alignment_line3 ) are present only in the table that stores imperfect microsatellites ( chloromitoimperfectmicrosatellite ) .
figure 1.schematic illustration showing the flow of the organization of the data in chloromitossrdb .
structure of the table chloromitometa that stores the meta - information of all the mitochondrial and chloroplast genomes structure of the tables chloromitoperfectmicrosatellite and chloromitoimperfectmicrosatellite that store the repeat information of all perfect and imperfect microsatellites of mitochondrial and chloroplast genomes the last four columns ( imperfection , alignment_line1 , alignment_line2 and alignment_line3 ) are present only in the table that stores imperfect microsatellites ( chloromitoimperfectmicrosatellite ) .
the information for the genome composition ( a- , t- , g- and c- counts , etc
. ) has been computed from the flat files obtained from the ncbi refseq database ( table 1 ) .
the complete repeat information of the database is stored in two different tables ( refer table 2 ) , storing the perfect and imperfect repeats of all chloroplast and mitochondrial genomes .
the repeat information includes the details of individual repeats such as the sequence i d , start and end coordinates of the repeat , the repeating motif , number of iterations , total tract length , nucleotide composition of the repeat , protein information of coding repeats . in addition
, the table displaying the imperfect repeats also stores the imperfection percentage and alignment information that can be used to study the evolution of these repeats .
the complete browsing outlay of the chloromitossrdb is displayed ( fig . 2 ) .
the curated information is organized into several search patterns , and proper navigation pages have been provided .
the curated information from the imex has been processed further according to gene ids , organism name , and the ssrs were sorted according to the coding or non - coding regions .
the position of the coding regions has been determined using the annotated ptt files of each chloroplast and mitochondrial genome as downloaded from the ncbi refseq database .
this figure appears in colour in the online version of dna research . how to browse : schematic browsing of chloromitossrdb .
chloromitossrdb interface provides information on several repeat statistics , including the distribution of the repeat types , length of the motifs and their positions ( coding or non - coding repeats ) .
the querying of chloromitossrdb through the web interface is organized into three search patterns that accomplish all interface functionalities : query page , result page and report page : ( i ) the first search pattern is according to the organelle classification and it has been classified into chloroplast and mitochondrial genomes , ( ii ) the second search pattern has been classified according to the type of repeat pattern ( perfect or imperfect ) and ( iii ) . the last search pattern allows the user to select the repeat size . with the appropriate selection pattern
, the user will be directed to the organelle - specific page ( chloroplast and mitochondrial ) containing the list of the organism for which the ssrs have been identified , which are further linked to the organism - specific repeat pages for further information on the distribution of the repetitive tracts . to ease the access of the database and to enhance the user functionality
, we also provide chloroplast and mitochondrial repeat - specific pages alphabetically ordered according to the organism name .
an advanced search option has been provided to filter the repeats based on the user - specific criteria allowing the user to search for a repeat region of a specific length .
an option to export the search results and the repeat information in excel format has been provided , so that the user can save and analyse the repeats , design primers and can utilize the information for further downstream processing of the observed repeats . a query page for every organism
is directed to a chloromitossrdb repeat summary page for organism - specific summary page that gives a detailed illustration of the distribution of the perfect and the imperfect repeats distribution and the genome composition using bar and pie charts . the genome composition and the repeat occurrence graphs
were generated dynamically based on the repeat information using libchart , a php chart drawing library ( http://naku.dohcrew.com/libchart/ ) .
the repeat pattern summary displayed on the organism specific page are clickable links , which redirects and give further information on the start and end of the ssr repeat containing tract , motif and the occurrence of the respective repeat pattern across the genomes .
mutations in the ssr stretches prevailing in the coding region may affect the subsequent transcription and translation of the gene harbouring the repetitive stretches of ssrs .
mutations in chloroplast ssrs ( mutation rates at cpssr loci as between 3.2 10 and 7.9 10 ) have been described as low when compared with substitution rates .
recently , it was observed that the plant mitochondrial substitution rates are relatively lower when compared with the invertebrates and mammalian mitochondrial genomes . to evaluate the distribution of the ssrs in the coding regions ,
the repeat - rich regions on the organism page have been linked to the corresponding protein ids ( ncbi , www.ncbi.nlm.nih.gov/ ) , in case of coding repeats , which can shed light on the evolution of these repeated regions either through mutational bias or through selective forces in further ongoing work .
we have consecutively constructed a database chloromitossrdb that displays curated information of wide spread occurrences of genomic repeats in chloroplast and mitochondrial genomes available so far , and we will be constantly updating chloromitossrdb with the new chloroplast and mitochondrial genomes as and when they are released .
the repeats in the coding regions of the genes may prove to be candidate markers to study the functional role of repeats associated with the genes , as possible markers for species delimitation , evolutionary analyses and also for evaluating the germplasm and to hypothesize conservation strategies for endangered species .
in future release , we will make efforts to upgrade the primer pair information for the repeat - rich regions and will also upgrade the database with the systematic visualization of imperfect alignments through the availability of hyperlinked pages in case of imperfect repeats .
we believe that chloromitossrdb will serve as a standard database for exploring and understanding genomic repeats in organelle genomes , and the data represented in chloromitossrdb make a good starting point for further exploratory investigations on ssr polymorphism , large comparative genome comparison and provide a platform to understand the repetitive nature of organelle genomes .
this work was supported by biomasfor ( z0912003i , italy ) and ec fp7 ( biosupport , bulgaria ) .
m.a.f . was supported by a grant from the spanish ministerio de ciencia e inovacin ( bfu2009 - 12022 ) .
Output:
| microsatellites or simple sequence repeats ( ssrs ) are repetitive stretches of nucleotides ( a , t , g , c ) that are distributed either as single base pair stretches or as a combination of two- to six - nucleotides units that are non - randomly distributed within coding and in non - coding regions of the genome .
chloromitossrdb is a complete curated web - oriented relational database of perfect and imperfect repeats in organelle genomes . the present version of the database contains perfect and imperfect ssrs of 2161 organelle genomes ( 1982 mitochondrial and 179 chloroplast genomes ) .
we detected a total of 5838 chloroplast perfect ssrs , 37 297 chloroplast imperfect ssrs , 5898 mitochondrial perfect ssrs and 50 355 mitochondrial imperfect ssrs across these genomes .
the repeats have been further hyperlinked to the annotated gene regions ( coding or non - coding ) and a link to the corresponding gene record in national center for biotechnology information(www.ncbi.nlm.nih.gov/ ) to identify and understand the positional relationship of the repetitive tracts .
chloromitossrdb is connected to a user - friendly web interface that provides useful information associated with the location of the repeats ( coding and non - coding ) , size of repeat , motif and length polymorphism , etc .
chloromitossrdb will serve as a repository for developing functional markers for molecular phylogenetics , estimating molecular variation across species .
database url : chloromitossrdb can be accessed as an open source repository at www.mcr.org.in/chloromitossrdb . |
PubmedSumm118736 | ***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: sexual health is defined in part by the world health organization as a state of physical , emotional , mental , and social well - being in relation to sexuality ; not merely the absence of disease , dysfunction , or infirmity.1 the definition is based on landmark publications from sexual health researchers over the last century .
once normal is defined , abnormal can then be recognized , defined and ultimately treated .
diminished sexual desire is the most widely recognized sexual complaint reported in epidemiologic studies.24 hypoactive sexual desire disorder ( hsdd ) is the formal term used when diagnosing and treating women with various types and causes of diminished sexual desire .
despite over three decades since its definition and multiple changes in an attempt to improve the accuracy of the diagnosis , established treatment paradigms are lacking .
medical treatments for hsdd have relied on homeopathic products and off - label use of prescription medications .
this has been due in part to a poor understanding of the biology of desire . in 2015
, the us food and drug administration ( fda ) approved flibanserin for the treatment of hsdd in premenopausal women .
flibanserin is a centrally acting receptor agonist and antagonist affecting serotonin , dopamine and norepinephrine activity.5 these neurotransmitters are believed to be crucial in the biology of desire .
flibanserin s use has the potential to be the cornerstone in treatment paradigms for premenopausal women with hsdd .
theoretical models to define human sexual response have advanced over time . in the 1920s , sigmund freud described the sexual response as a complicated sequence of related events ultimately resulting in the execution of the sex act.6 in the 1960s , william masters and virginia johnson proposed a four - stage linear model to characterize the physical and emotional changes that occur when a person engages in sexual activities.7 the duration and characteristics of each stage is unique to a person , and vary between men and women .
the masters and johnson model starts with excitement , whereby physiologic signs of arousal are noticed , such as an increase in heart rate , increased blood flow to the genitals and faster breathing .
excitement is then followed by plateau . the duration of this stage is less than the former ; however , it is characterized by an increase in the physiologic responses that carry over from excitement .
the duration of this stage is the shortest of all only a few seconds . in this stage ,
changes from the initial stages are at their peak , which eventually results in the release of sexual tension and procession to the final stage , resolution . during resolution ,
all heightened conditions return back to normal and a feeling of satisfaction , fatigue and exhaustion is normal .
groundbreaking , this model for the human sexual response was revered . some researchers , however , saw room for improvement , mainly because the sexual response cycle lacked a fundamental aspect of human sexuality , a psychological component .
one such researcher was helen kaplan who , in 1970s , modified the sexual response linear paradigm by adding the desire stage and effectively compressing the four - stage model into a three - stage process : desire , arousal and orgasm.8,9 in the desire stage , a person is psychologically priming for sex .
this is characterized by physical arousal which may result in an erection for men or vaginal lubrication for women .
orgasm , the last stage , includes release of sexual tension and a general feeling of satisfaction . a key point of kaplan s model was to emphasize the fact that sexual dysfunctions can occur in any of the three stages , including the psychological stage of desire , resulting in the need for various interventions for each type of dysfunction . in the 1980s
harold lief held similar views as kaplan , and independently proposed a five - stage linear model where desire is followed by arousal then vasocongestion , orgasm and ultimately satisfaction.10 desire represented a notion to engage in sexual activity , with arousal being a physical awareness of changes associated with anticipation of sexual activity .
orgasm was a systematic release of sexual tension and satisfaction denoted by the global sense of wellbeing at the completion of sexual activity . despite being linear
it was coined the desire , arousal , vaso , congestion , orgasm , satisfaction cycle . also similar to kaplan
proposed a four - stage model for sexual response that progressed in a cyclic fashion : seduction , sensations , surrender , and reflection.11 until this time , all models proposed for human sexual response were linear .
each stage in the whipple model encompasses aspects from the multistage models proposed by earlier researchers .
seduction involves desire , sensations encompass excitement and plateau , surrender is related to orgasm and reflection is akin to resolution .
this model emphasizes the positive reinforcement effect of sex , such that each positive sexual experience reinforces a desire for more sexual experiences . in the early 2000s , rosemary basson built on whipple s cyclic model by expanding on sexual desire and emphasizing an emotional satisfaction aspect to sex.12 in addition
she described a woman s sexual response in dynamic nonlinear terms whereby a woman s sexual response ultimately results in satisfaction .
she described a process where a woman can enter the sexual response cycle at various stages as each stage can affect another in either direction .
the goal in her model is satisfaction , both physical and emotional and is determined by the individual .
similar to earlier models , the basson model acknowledged multiple entry points for the treatment of sexual dysfunctions . the formal history defining low sexual desire originated in the diagnostic classification system of the american psychiatric association .
the diagnostic and statistical manual of mental disorders ( dsm ) in 1980 first published its definition with changes occurring throughout updated publications .
it was defined as persistently or recurrently deficient or absent sexual fantasies and desire for sexual activity .
the definition of hsdd has developed over time to address current clinical information in an attempt to better diagnose and treat this condition . between 1994 and 2000
dsm - iv further supplemented the original definition with added criteria of the disorder requiring marked distress or interpersonal difficulty and not better accounted for by another sexual disorder and not due to the direct effects of drug abuse or a general medical or psychologic condition .
hsdd could further be classified as primary or secondary , acquired or lifelong , and generalized or situational . in the 2013 dsm-5 edition ,
disorders of desire and arousal were joined into one classification titled female sexual interest / excitement and arousal disorder ( fsiad ) .
the dsm-5 classification of fsiad requires that the lack of sexual interest must cause distress 75%100% of the time with > 6 months of persistence .
regardless of the adjustment in the dsm terminology from hsdd to fsiad , hsdd still exists as a center part of fsiad .
the complexities of the human sexual response rival those of any physiologic response in medicine .
testosterone , often thought of as a male hormone , is vital in normal sexual function in women .
free testosterone is crucial as it affects key receptors both centrally and peripherally to promote a normal sexual response and desire . for women
, testosterone is primarily produced from precursor hormones produced in the adrenal glands with final conversion in various locations including the adrenals , ovaries and peripheral tissue.13 although precursor hormones may also promote normal sexual responses , testosterone has the greatest effect . in women it acts centrally to promote desire as well as peripherally in the vulva and vagina to facilitate arousal by optimizing blood flow and facilitating lubrication.14 estrogen is another key sexual hormone in women .
identified in three major forms , estrone , estradiol and estriol , estrogen is also derived from precursor hormones with a central and peripheral effect promoting the sexual response and desire in women.15,16 centrally estradiol promotes sexual desire such as testosterone , it acts peripherally in the vulva and vagina to promote blood flow , lubrication and the arousal response.1720 nitric oxide is a chemotactic agent that can influence the sexual response . it is a potent vasodilator throughout the body and facilitates blood flow and lubrication to the vulva and vagina . optimizing blood flow and lubrication to the sexual organs promotes the arousal response facilitating a pleasurable experience .
dopamine , norepinephrine and serotonin are three important centrally acting neurotransmitters of the limbic system vital for normal sexual health and associated with sexual desire.21,22 dopamine positively influences pleasure and reward pathways in the brain .
sexual activity involving desire is a pleasurable activity rewarded with satisfaction when all goes well .
thus increasing dopamine levels has the potential to increase sexual desire.23 norepinepherine is another important neurotransmitter for sexual desire and is associated with motivation .
it has been shown to be elevated during sexual arousal and orgasm , both of which are motivating factors that can positively affect desire.24 serotonin is an inhibitory neurotransmitter for sexual desire and has been shown to be activated during periods of sexual inhibition and to restrict excitatory systems.21,25,26 in the absence of an fda approved medication to treat sexual dysfunction , homeopathic or alternative products have been promoted as a treatment option based on an understanding of the biology of desire .
the fda does not regulate alternative products such as herbal or nutritional supplements , so while proprietary alternative product companies can claim their products enhance the sexual response in women , they are not required to publish studies to support such claims .
that said , the public at large is eager to accept an alternative option especially when no other options exist .
thus it should come as no surprise that various prescription medications have been used in an attempt to treat hsdd ( table 2 ) .
a combination therapy of esterified estrogen and methyltestosterone is approved by fda to treat hot flashes and is also commonly used off - label to treat hsdd.27 multiple studies report improved sexual desire suggesting it is a viable treatment option for hsdd.2832 bupropion is a norepinephrine and dopamine reuptake inhibitor approved by the fda for the treatment of depression .
bupropion has been studied for its effect on sexual function and hsdd with results showing improved sexual desire in depressed patients as well as improved desire in patients with serotonin specific reuptake inhibitor induced hsdd.23,33,34 these results have led to its off - label use in the treatment of hsdd .
inhibition of pde5 promotes vasodilation via the sustained effects of nitric oxide in the vascular system throughout the body including the vulva and vagina .
fda approved for the treatment of erectile dysfunction and pulmonary hypertension , sildenafil has been studied for off - label use in women with hsdd with minimal benefit.25,26,35 buspirone is an azapirone , a class of drugs commonly used as anti - anxiety agents .
it is an fda approved drug for the treatment of general anxiety and binds to both serotonin and dopamine receptors in the brain .
it has been studied for its potential to affect sexual function and possible off - label use in hsdd with some promise.3638 flibanserin was first studied as a potential antidepressant due to its proposed mechanism of action .
flibanserin is a dynamic compound that affects serotonin , dopamine and norepinephrine activity with affinity for 5-ht1a , 5-ht2a , 5-ht2b , 5ht2c and dopamine d4 receptors in the brain.5,39,40 it was initially found to lower serotonin and raise dopamine and norepinephrine activity in the prefrontal cortex in rat studies.41 it was advanced to clinical human trials based on an understanding of these neurotransmitters and their role in depression but failed to prove effective in treating depression.42 it was , however , noted to improve sexual desire in depressed woman with decreased sexual desire at baseline.43 this improvement in sexual desire was felt to be related to flibanserin s effect on neurotransmitters in the limbic system and this led to a rerouting of the development of the drug as a potential nonhormonal treatment for hsdd.44 the results of four phase three and one safety and tolerability trials in premenopausal women initiated by the manufacturer were subsequently published in the journal of sexual medicine from 2011 to 2013 and formed the basis for flibanserin s fda approval process .
the first phase iii trial titled researching outcomes on sustained efficacy ( rose ) was a multicenter prospective withdrawal study.45 women diagnosed with hsdd via clinical interview in conjunction with a validated sexual health questionnaire who proved compliance with an electronic diary ( e - diary ) validated to capture sexual health information who were in stable monogamous heterosexual relationships with an otherwise sexually functional partner were enrolled .
exclusion criteria were exhaustive and included both medical and psychological conditions , various medications , other sexual dysfunctions in addition to hsdd or at the discretion of the investigator .
dosing options were 50 mg nightly , 50 mg twice daily or 100 mg each night .
women were evaluated with the e - diary , validated sexual health questionnaires and direct questions by the investigator to track effects on sexual desire and for adverse events . at the completion of the first 24 weeks responders defined as those women having an increase in satisfying sexual events ( sse ) of at least two per month or at least four desire days per month
were then randomly assigned flibanserin or placebo in a double blind fashion for another 24 weeks .
one hundred sixty - three women were randomized to flibanserin with 146 completing the study and 170 women were randomized to placebo with 146 completing the study . at the completion
all women were then followed for 4 weeks to assess efficacy , adverse events and withdrawal events .
overall at the end of the initial open label period 64% reported they were much or very much improved with improvements noted in sse and in the validated sexual health instruments . at the completion of the 24-week blinded period .
primary outcomes were assessed using sse and e - diary with secondary outcomes assessed with validated sexual health questionnaires .
mean sse and validated sexual health questionnaire scores did not retain their baseline levels reached at the completion of the initial open label 24 weeks . however , the flibanserin group s scores were significantly better than the placebo group at the completion of the 24-week blinded period .
flibanserin was noted to be well tolerated with the most common adverse events being nausea , somnolence , fatigue , headache , dizziness , irritability and depression .
similar aes were noted in the second phase of the study with many reported more commonly in the placebo group which had twice the discontinuation rate as the flibanserin group . there were no significant withdrawal symptoms noted .
the dose ascending study over half - a - year ( daisy ) was published in 2012.46 this randomized placebo controlled 24-week prospective double blinded multicenter trial compared placebo to flibanserin 25 mg twice daily , 50 mg flibanserin twice daily and 100 mg nightly for safety and efficacy in premenopausal women diagnosed with hsdd via clinical interview and validated sexual health questionnaire .
study inclusion and exclusion criteria were similar to the rose trial , such as rose , e - diary entries and validated sexual health questionnaires as well as recorded global impression of improvement were used for primary and secondary outcome measures .
one thousand five hundred eighty - one women were enrolled in roughly equal numbers for each group .
primary outcomes were more robust for the 100 mg nightly flibanserin dose indicated by significant improvement in sse scores .
secondary outcomes were significantly improved for all flibanserin doses by sexual health questionnaire measures and significant improvement was noted for the 50 and 100 mg regimens recorded by global impression of improvement over placebo .
e - diary desire scores , however , did not show significant improvement for any flibanserin dose .
reported aes were similar to the rose trial with discontinuation rates for all flibanserin doses being 13.4% and placebo being 10.1% .
also in 2012 the results of evaluation of the impact on sexuality with evening treatment ( violet ) trial were reported.47 similar to daisy it was a 24-week prospective randomized placebo controlled double blinded multicenter trial .
it compared 50 and 100 mg flibanserin dosed nightly to placebo for safety and efficacy in premenopausal women diagnosed with hsdd in the same fashion as the previous trials .
in addition this trial used e - diary , validated sexual health questionnaires and patient global assessment of improvement to assess primary and secondary outcomes .
eight hundred eighty women equally distributed were enrolled and study characteristics were similar to daisy .
each flibanserin dose significantly improved the number of sse and specific measures on sexual health questionnaires as well as global improvement evaluations compared to placebo , however neither dose showed improvement in e - diary scores . reported
the discontinuation rates due to aes for placebo , 50 mg flibanserin and 100 mg flibanserin were 3.4% , 7.8% and 11.4% , respectively .
every evening of flibanserin versus placebo in premenopausal women with hsdd ( begonia ) was the last of the phase three 24-week prospective randomized placebo controlled double blinded multicenter trials and was published in 2013.48 begonia compared 100 mg flibanserin each night to placebo in women diagnosed with hsdd in the same fashion previously mentioned .
it had noted changes in study design from daisy and violet for inclusion and exclusion as well as the design for outcome measures using only one validated sexual health questionnaire score and sse for primary outcome measures with secondary outcomes measured with two sexual health questionnaires .
aes were similar to rose , daisy and violet with discontinuation rates for placebo and flibanserin as 3.7% and 9.6% , respectively .
the results of a 52-week flexible dose open label uncontrolled safety and tolerability trial deemed sunflower were published in 2012.49 this trial was developed to assess the safety and tolerability of flibanserin and enrolled 1,723 women who completed a previous flibanserin trial .
women were allowed flexible dosing of flibanserin to include 25 mg twice daily , 50 mg twice daily , 50 mg nightly or 100 mg nightly .
primary outcomes were a measure of known flibanserin aes , discontinuation due to aes and serious aes .
somnolence was the most prevalent ae experienced by 15.8% of women with all other aes found in < 8% of women .
the discontinuation rate due to aes was 10.7% , with serious aes reported by 1.2% of women .
flibanserin was first submitted for approval in 2010 based largely on efficacy and safety data of the previously mentioned trials.50 however , the fda felt that the lack of efficacy demonstrated by e - diary data was concerning .
in addition the fda felt that aes specifically somnolence as well as the effects of alcohol and other commonly used drugs taken with flibanserin were highly concerning .
finally , the fda felt the trials were too restrictive in their inclusion and exclusion criteria precluding adequate assessment .
flibanserin s approval was initially denied but with recommendations for resubmission . on august 8 , 2015 after resubmission the fda felt that with restrictions to include risk evaluation management strategies , strong labeling to include a black box warning , and postmarketing studies flibanserin would fill an unmet need for women with hsdd .
theoretical models to define human sexual response have advanced over time . in the 1920s , sigmund freud described the sexual response as a complicated sequence of related events ultimately resulting in the execution of the sex act.6 in the 1960s , william masters and virginia johnson proposed a four - stage linear model to characterize the physical and emotional changes that occur when a person engages in sexual activities.7 the duration and characteristics of each stage is unique to a person , and vary between men and women .
the masters and johnson model starts with excitement , whereby physiologic signs of arousal are noticed , such as an increase in heart rate , increased blood flow to the genitals and faster breathing .
the duration of this stage is less than the former ; however , it is characterized by an increase in the physiologic responses that carry over from excitement .
the duration of this stage is the shortest of all only a few seconds . in this stage ,
changes from the initial stages are at their peak , which eventually results in the release of sexual tension and procession to the final stage , resolution . during resolution , all heightened conditions return back to normal and a feeling of satisfaction , fatigue and exhaustion is normal .
groundbreaking , this model for the human sexual response was revered . some researchers , however , saw room for improvement , mainly because the sexual response cycle lacked a fundamental aspect of human sexuality , a psychological component .
one such researcher was helen kaplan who , in 1970s , modified the sexual response linear paradigm by adding the desire stage and effectively compressing the four - stage model into a three - stage process : desire , arousal and orgasm.8,9 in the desire stage , a person is psychologically priming for sex .
this is characterized by physical arousal which may result in an erection for men or vaginal lubrication for women .
orgasm , the last stage , includes release of sexual tension and a general feeling of satisfaction . a key point of kaplan s model was to emphasize the fact that sexual dysfunctions can occur in any of the three stages , including the psychological stage of desire , resulting in the need for various interventions for each type of dysfunction .
in the 1980s harold lief held similar views as kaplan , and independently proposed a five - stage linear model where desire is followed by arousal then vasocongestion , orgasm and ultimately satisfaction.10 desire represented a notion to engage in sexual activity , with arousal being a physical awareness of changes associated with anticipation of sexual activity .
orgasm was a systematic release of sexual tension and satisfaction denoted by the global sense of wellbeing at the completion of sexual activity . despite being linear
it was coined the desire , arousal , vaso , congestion , orgasm , satisfaction cycle . also similar to kaplan
he emphasized a multifaceted approach when treating sexual disorders . in the 1990s beverly whipple proposed a four - stage model for sexual response that progressed in a cyclic fashion : seduction , sensations , surrender , and reflection.11 until this time , all models proposed for human sexual response were linear .
each stage in the whipple model encompasses aspects from the multistage models proposed by earlier researchers .
seduction involves desire , sensations encompass excitement and plateau , surrender is related to orgasm and reflection is akin to resolution .
this model emphasizes the positive reinforcement effect of sex , such that each positive sexual experience reinforces a desire for more sexual experiences . in the early 2000s , rosemary basson built on whipple s cyclic model by expanding on sexual desire and emphasizing an emotional satisfaction aspect to sex.12 in addition
she described a woman s sexual response in dynamic nonlinear terms whereby a woman s sexual response ultimately results in satisfaction .
she described a process where a woman can enter the sexual response cycle at various stages as each stage can affect another in either direction .
the goal in her model is satisfaction , both physical and emotional and is determined by the individual .
similar to earlier models , the basson model acknowledged multiple entry points for the treatment of sexual dysfunctions .
the formal history defining low sexual desire originated in the diagnostic classification system of the american psychiatric association .
the diagnostic and statistical manual of mental disorders ( dsm ) in 1980 first published its definition with changes occurring throughout updated publications .
it was defined as persistently or recurrently deficient or absent sexual fantasies and desire for sexual activity .
the definition of hsdd has developed over time to address current clinical information in an attempt to better diagnose and treat this condition . between 1994 and 2000
dsm - iv further supplemented the original definition with added criteria of the disorder requiring marked distress or interpersonal difficulty and not better accounted for by another sexual disorder and not due to the direct effects of drug abuse or a general medical or psychologic condition .
hsdd could further be classified as primary or secondary , acquired or lifelong , and generalized or situational . in the 2013 dsm-5 edition ,
disorders of desire and arousal were joined into one classification titled female sexual interest / excitement and arousal disorder ( fsiad ) .
the dsm-5 classification of fsiad requires that the lack of sexual interest must cause distress 75%100% of the time with > 6 months of persistence .
regardless of the adjustment in the dsm terminology from hsdd to fsiad , hsdd still exists as a center part of fsiad .
the complexities of the human sexual response rival those of any physiologic response in medicine .
testosterone , often thought of as a male hormone , is vital in normal sexual function in women .
free testosterone is crucial as it affects key receptors both centrally and peripherally to promote a normal sexual response and desire . for women
, testosterone is primarily produced from precursor hormones produced in the adrenal glands with final conversion in various locations including the adrenals , ovaries and peripheral tissue.13 although precursor hormones may also promote normal sexual responses , testosterone has the greatest effect . in women it acts centrally to promote desire as well as peripherally in the vulva and vagina to facilitate arousal by optimizing blood flow and facilitating lubrication.14 estrogen is another key sexual hormone in women .
identified in three major forms , estrone , estradiol and estriol , estrogen is also derived from precursor hormones with a central and peripheral effect promoting the sexual response and desire in women.15,16 centrally estradiol promotes sexual desire such as testosterone , it acts peripherally in the vulva and vagina to promote blood flow , lubrication and the arousal response.1720 nitric oxide is a chemotactic agent that can influence the sexual response . it is a potent vasodilator throughout the body and facilitates blood flow and lubrication to the vulva and vagina .
optimizing blood flow and lubrication to the sexual organs promotes the arousal response facilitating a pleasurable experience .
dopamine , norepinephrine and serotonin are three important centrally acting neurotransmitters of the limbic system vital for normal sexual health and associated with sexual desire.21,22 dopamine positively influences pleasure and reward pathways in the brain .
sexual activity involving desire is a pleasurable activity rewarded with satisfaction when all goes well . thus increasing dopamine levels has the potential to increase sexual desire.23 norepinepherine is another important neurotransmitter for sexual desire and is associated with motivation .
it has been shown to be elevated during sexual arousal and orgasm , both of which are motivating factors that can positively affect desire.24 serotonin is an inhibitory neurotransmitter for sexual desire and has been shown to be activated during periods of sexual inhibition and to restrict excitatory systems.21,25,26
in the absence of an fda approved medication to treat sexual dysfunction , homeopathic or alternative products have been promoted as a treatment option based on an understanding of the biology of desire .
the fda does not regulate alternative products such as herbal or nutritional supplements , so while proprietary alternative product companies can claim their products enhance the sexual response in women , they are not required to publish studies to support such claims .
that said , the public at large is eager to accept an alternative option especially when no other options exist .
thus it should come as no surprise that various prescription medications have been used in an attempt to treat hsdd ( table 2 ) .
a combination therapy of esterified estrogen and methyltestosterone is approved by fda to treat hot flashes and is also commonly used off - label to treat hsdd.27 multiple studies report improved sexual desire suggesting it is a viable treatment option for hsdd.2832 bupropion is a norepinephrine and dopamine reuptake inhibitor approved by the fda for the treatment of depression .
bupropion has been studied for its effect on sexual function and hsdd with results showing improved sexual desire in depressed patients as well as improved desire in patients with serotonin specific reuptake inhibitor induced hsdd.23,33,34 these results have led to its off - label use in the treatment of hsdd .
inhibition of pde5 promotes vasodilation via the sustained effects of nitric oxide in the vascular system throughout the body including the vulva and vagina .
fda approved for the treatment of erectile dysfunction and pulmonary hypertension , sildenafil has been studied for off - label use in women with hsdd with minimal benefit.25,26,35 buspirone is an azapirone , a class of drugs commonly used as anti - anxiety agents .
it is an fda approved drug for the treatment of general anxiety and binds to both serotonin and dopamine receptors in the brain .
it has been studied for its potential to affect sexual function and possible off - label use in hsdd with some promise.3638
flibanserin was first studied as a potential antidepressant due to its proposed mechanism of action .
flibanserin is a dynamic compound that affects serotonin , dopamine and norepinephrine activity with affinity for 5-ht1a , 5-ht2a , 5-ht2b , 5ht2c and dopamine d4 receptors in the brain.5,39,40 it was initially found to lower serotonin and raise dopamine and norepinephrine activity in the prefrontal cortex in rat studies.41 it was advanced to clinical human trials based on an understanding of these neurotransmitters and their role in depression but failed to prove effective in treating depression.42 it was , however , noted to improve sexual desire in depressed woman with decreased sexual desire at baseline.43 this improvement in sexual desire was felt to be related to flibanserin s effect on neurotransmitters in the limbic system and this led to a rerouting of the development of the drug as a potential nonhormonal treatment for hsdd.44 the results of four phase three and one safety and tolerability trials in premenopausal women initiated by the manufacturer were subsequently published in the journal of sexual medicine from 2011 to 2013 and formed the basis for flibanserin s fda approval process .
the first phase iii trial titled researching outcomes on sustained efficacy ( rose ) was a multicenter prospective withdrawal study.45 women diagnosed with hsdd via clinical interview in conjunction with a validated sexual health questionnaire who proved compliance with an electronic diary ( e - diary ) validated to capture sexual health information who were in stable monogamous heterosexual relationships with an otherwise sexually functional partner were enrolled .
exclusion criteria were exhaustive and included both medical and psychological conditions , various medications , other sexual dysfunctions in addition to hsdd or at the discretion of the investigator .
dosing options were 50 mg nightly , 50 mg twice daily or 100 mg each night .
women were evaluated with the e - diary , validated sexual health questionnaires and direct questions by the investigator to track effects on sexual desire and for adverse events . at the completion of the first 24 weeks responders defined as those women having an increase in satisfying sexual events ( sse ) of at least two per month or at least four desire days per month
were then randomly assigned flibanserin or placebo in a double blind fashion for another 24 weeks .
one hundred sixty - three women were randomized to flibanserin with 146 completing the study and 170 women were randomized to placebo with 146 completing the study . at the completion
all women were then followed for 4 weeks to assess efficacy , adverse events and withdrawal events .
overall at the end of the initial open label period 64% reported they were much or very much improved with improvements noted in sse and in the validated sexual health instruments . at the completion of the 24-week blinded period .
primary outcomes were assessed using sse and e - diary with secondary outcomes assessed with validated sexual health questionnaires .
mean sse and validated sexual health questionnaire scores did not retain their baseline levels reached at the completion of the initial open label 24 weeks . however , the flibanserin group s scores were significantly better than the placebo group at the completion of the 24-week blinded period .
flibanserin was noted to be well tolerated with the most common adverse events being nausea , somnolence , fatigue , headache , dizziness , irritability and depression .
similar aes were noted in the second phase of the study with many reported more commonly in the placebo group which had twice the discontinuation rate as the flibanserin group . there were no significant withdrawal symptoms noted .
the dose ascending study over half - a - year ( daisy ) was published in 2012.46 this randomized placebo controlled 24-week prospective double blinded multicenter trial compared placebo to flibanserin 25 mg twice daily , 50 mg flibanserin twice daily and 100 mg nightly for safety and efficacy in premenopausal women diagnosed with hsdd via clinical interview and validated sexual health questionnaire .
study inclusion and exclusion criteria were similar to the rose trial , such as rose , e - diary entries and validated sexual health questionnaires as well as recorded global impression of improvement were used for primary and secondary outcome measures .
one thousand five hundred eighty - one women were enrolled in roughly equal numbers for each group .
primary outcomes were more robust for the 100 mg nightly flibanserin dose indicated by significant improvement in sse scores .
secondary outcomes were significantly improved for all flibanserin doses by sexual health questionnaire measures and significant improvement was noted for the 50 and 100 mg regimens recorded by global impression of improvement over placebo .
e - diary desire scores , however , did not show significant improvement for any flibanserin dose .
reported aes were similar to the rose trial with discontinuation rates for all flibanserin doses being 13.4% and placebo being 10.1% .
also in 2012 the results of evaluation of the impact on sexuality with evening treatment ( violet ) trial were reported.47 similar to daisy it was a 24-week prospective randomized placebo controlled double blinded multicenter trial .
it compared 50 and 100 mg flibanserin dosed nightly to placebo for safety and efficacy in premenopausal women diagnosed with hsdd in the same fashion as the previous trials .
in addition this trial used e - diary , validated sexual health questionnaires and patient global assessment of improvement to assess primary and secondary outcomes .
eight hundred eighty women equally distributed were enrolled and study characteristics were similar to daisy .
each flibanserin dose significantly improved the number of sse and specific measures on sexual health questionnaires as well as global improvement evaluations compared to placebo , however neither dose showed improvement in e - diary scores . reported
the discontinuation rates due to aes for placebo , 50 mg flibanserin and 100 mg flibanserin were 3.4% , 7.8% and 11.4% , respectively .
every evening of flibanserin versus placebo in premenopausal women with hsdd ( begonia ) was the last of the phase three 24-week prospective randomized placebo controlled double blinded multicenter trials and was published in 2013.48 begonia compared 100 mg flibanserin each night to placebo in women diagnosed with hsdd in the same fashion previously mentioned .
it had noted changes in study design from daisy and violet for inclusion and exclusion as well as the design for outcome measures using only one validated sexual health questionnaire score and sse for primary outcome measures with secondary outcomes measured with two sexual health questionnaires .
aes were similar to rose , daisy and violet with discontinuation rates for placebo and flibanserin as 3.7% and 9.6% , respectively .
the results of a 52-week flexible dose open label uncontrolled safety and tolerability trial deemed sunflower were published in 2012.49 this trial was developed to assess the safety and tolerability of flibanserin and enrolled 1,723 women who completed a previous flibanserin trial .
women were allowed flexible dosing of flibanserin to include 25 mg twice daily , 50 mg twice daily , 50 mg nightly or 100 mg nightly .
primary outcomes were a measure of known flibanserin aes , discontinuation due to aes and serious aes .
the discontinuation rate due to aes was 10.7% , with serious aes reported by 1.2% of women .
flibanserin was first submitted for approval in 2010 based largely on efficacy and safety data of the previously mentioned trials.50 however , the fda felt that the lack of efficacy demonstrated by e - diary data was concerning .
in addition the fda felt that aes specifically somnolence as well as the effects of alcohol and other commonly used drugs taken with flibanserin were highly concerning .
finally , the fda felt the trials were too restrictive in their inclusion and exclusion criteria precluding adequate assessment .
flibanserin s approval was initially denied but with recommendations for resubmission . on august 8 , 2015 after resubmission
the fda felt that with restrictions to include risk evaluation management strategies , strong labeling to include a black box warning , and postmarketing studies flibanserin would fill an unmet need for women with hsdd .
sexual health and general health go hand in hand and the treatment of sexual dysfunction has global implications on health and wellbeing .
although early researchers tried to conceptualize the sexual response in linear terms , the later researchers have formulated a nonlinear model that seems to much better describe a woman s sexual response .
this has led to improved and more accurate definitions for sexual dysfunction and hsdd published in the regularly updated versions of the dsm . despite a better female sexual health model and more clear definitions ,
many homeopathic options have been formulated with limited data to support efficacy and until recently the only fda approved medications to treat sexual dysfunction in women were used off - label . that changed on august 8 , 2015 when for the first time the fda approved flibanserin for treatment of hsdd in premenopausal woman .
the authors , in full agreement with the fda , recognize that with strict adherence to prescribing guidelines flibanserin is now a clear and viable option for an unmet medical need in women .
Output:
| the objective of the authors is to highlight the historical complexities for the diagnosis and treatment of hypoactive sexual desire disorder ( hsdd ) with a focus on flibanserin .
a systematic review of the medical literature published in pubmed using the search terms hsdd and flibanserin was conducted .
each author reviewed the results of the systematic review for articles to include in this study .
hsdd is defined as a persistent or recurrent deficiency or absence of sexual fantasies and desire for sexual activity causing marked distress or interpersonal difficulty that is not better accounted for by another diagnosis . until 2015 , only homeopathic products and off - label use of prescription medications were medical treatment options for women with hsdd .
flibanserin , approved by the us food and drug administration ( fda ) in 2015 , is the first to target female hsdd in premenopausal women .
flibanserin is a centrally acting nonhormonal oral medication taken once daily that affects serotonin , dopamine and norepinephrine levels , the key neurotransmitters in the biology of desire . understanding prescribing guidelines and awareness of black box warnings is paramount for prescribers .
adherence to proper oversight will ensure flibanserin can fulfil an unmet need for an fda approved prescription medication for the treatment of hsdd in premenopausal women . |
PubmedSumm118737 | ***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: drop - in group medical appointments ( digmas ) were provided for adult patients who are encouraged to attend group discussions .
digmas have been developed for diabetes , hypertension , well - child care , fibromyalgia , and functional bowel disease .
prior studies using the group model have reported improvements in hemoglobin a1c , diabetic knowledge , and quality of life [ 24 ] .
this model has been shown to increase physician and staff productivity as well as decrease healthcare cost .
the physician addresses medical concerns , the behaviorist facilitates group discussion and psychosocial issues , and the asthma educator addresses specific questions regarding monitoring and equipment .
this allows for patient education and self - management instruction without the limitation of a formal didactic presentation . our program , which we renamed doctor interactive group medical appointments ,
digmas was designed to allow the physician to evaluate asthmatic patients on a weekly basis and provide disease education .
in addition , these group visits allow the patients to interact with one another in a mutually supportive environment .
sixty - four adult asthmatic patients were enrolled in our digma program and followed for four years .
patients were seen in 3 steps : vital signs and spirometry recorded by a nurse , an interim brief history , and physical exam performed by the physician , and a group session usually lasting 6090 minutes , supervised by the behaviorist . the asthma quality of life questionnaire ( aqlq ) was utilized to benchmark the patient 's perception of their disease prior to their first digma visit and at one year after the initial group appointment .
aqlq is a validated instrument that measures responses in 4 domains : activity limitation , symptoms , emotional function , and environmental exposure .
the patients performed spirometry testing and completed an analog scale used to measure compliance and satisfaction with care ( figure 3 ) . an asthma control test ( act )
act results were then reviewed with the group , comments were elicited , and concerns addressed .
forty - two patients continued the digma program for four years and were considered regular attendees ( table 1 ) .
the aqlq scores were improved by 373 points at the end of the first year .
the average improvement per patient in each domain of aqlq scores can be seen in figure 1 .
although there was no control group , baseline data on each patient was analyzed one year prior to study entry .
the four - year outcomes data showed the following : average baseline fvc was 85% predicted with the last available fvc unchanged at 85% predicted .
baseline act scores were 18 at the time the test became available and were slightly improved at 19 at the last digma appointment .
the analog scale provides a basis for psychosocial inquiries , rescue inhaler use , and nocturnal awakening .
the baseline patient satisfaction score was 30.46 and improved to 34.43 at the last determination .
average baseline rescue inhaler use was 4 per week compared to 1.5 per week at the last determination .
nocturnal awakening average was 5.5 per month compared to 1 per month at the last determination .
average baseline er and hospital claims data during the year prior to enrollment was 5 compared to 2 claims at the end of the last year of the four - year period for the forty - two patients who continued digma ( table 1 ) .
digma is a targeted intervention that fulfills the treatment goals of asthma care , as described by the national asthma education and prevention program ( naepp ) guidelines .
these treatment goals include symptom and exacerbation prevention , the maintenance of pulmonary function , optimized activity levels , meeting expectations of satisfaction with asthma care , and the provision of optimal pharmacotherapy .
asthma symptoms were monitored by the act , pulmonary functions were monitored by serial spirometry , activity level was monitored by the aqlq test , exacerbations were monitored by claims data , and satisfaction with care was monitored by the analog scale .
all survey scores were either unchanged or slightly improved after a four - year time period .
our digma results agreed with a previous report of chronically ill older adults in a health maintenance organization ( hmo ) involving 9 facilities and 19 physicians .
these investigators found no difference in the number of outpatient visits , but significantly fewer emergency visits and hospital admissions . during the first visit confidentiality agreements and consents
the treating physician provides a one - to - one visit prior to the group intervention .
visits were billed and reimbursed as individual office visits using existing current procedural terminology ( cpt ) codes ranging from 99212 to 99215 .
digma removed these barriers and provides extra value by allowing patients to attend any session at any time , providing easy access to spirometry , vaccines , prescription renewals , and health care advice as often as weekly if necessary .
the patients completed the analog evaluation at each visit which led to a discussion of satisfaction and compliance with care .
psychosocial factors were discussed for each patient by the behaviorist . often , individual patient concerns were discussed as a group leading to a dialog of experiences by other participants .
one of the primary goals was to enhance education , awareness , and disease understanding without the limitation of a formal lecture .
Output:
| our digma program was established to allow patients time to interact with an allergist , a behaviorist and an asthma educator in a group setting .
weekly meetings targeted patients with chronic asthma .
digmas typically last for 90 minute s and include 10 patients per session .
outcome parameters were established to assess the effectiveness of the program over a 4 year time period .
sixty four adult asthmatic patients were enrolled and followed for 4 years .
patients were seen in a group setting in groups of ten .
the aqlq test was administered each year .
spirometry , an analog self assessment scale and the act were administered at each visit .
forty two of the 64 patients were followed for a minimum of 3 visits to digma during four years .
the average baseline fvc was 85% predicted and remained unchanged .
fev1 was 78% baseline and was 77% at the last determination .
baseline rescue inhaler use was 4 per week compared to 1.5 per week at last visit .
act scores are 18 at baseline and 19 at last visit .
er claims are 5 at one year prior to enrollment and 2 at the last year of digma .
patient satisfaction improved from 30 to 34 at the last visit .
this was an effective , multidisciplinary asthma intervention that focused on behavior .
it fulfilled the goals of asthma care as described by the 2007 naepp guidelines . |
PubmedSumm118738 | ***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 success of root canal therapy is dependent upon a thorough knowledge of the root and root canal morphology .
this helps us to locate all the canals and properly clean , shape , and obturate the canal spaces in all dimensions.[13 ] slowey has suggested that mandibular first premolars , often called as
endodontist 's enigma , may present the greatest difficulty of all teeth to perform successful endodontic treatment .
this is because they are anatomically unpredictable , and often present with a wide variety of morphological rarities .
one such morphological oddity is the presence of two roots , with a reported incidence of 1.8% .
this article reports on the clinical case of a mandibular first premolar with two roots .
a 32 year old male patient reported to the department of conservative dentistry and endodontics at rajasthan dental college and hospital , with the chief complaint of pain in the posterior right mandibular tooth for the past 1 week .
radiographic examination of the tooth indicated an unusual anatomy of two roots , and also there was widening of the apical periodontium , indicating periapical pathology and the necessity for root canal treatment [ figure 1 ] .
pre - operative intra oral periapical radiograph of the mandibular right first premolar in the patient in the case study , showing an unusual anatomy of two roots , and widening of the apical periodontium the clinical examination , radiographic examination and vitality tests led to a diagnosis of acute apical periodontitis of the right mandibular first premolar requiring endodontic therapy .
the tooth was anaesthetized by way of right inferior alveolar nerve block using a 2% solution of lignocaine hydrochloride containing 1:80000 adrenaline ( lignox 2% a , warren , indoco ) .
endodontic access was prepared with a round diamond bur in a high speed airotor handpiece .
the pulp chamber was inspected with the aid of a magnifying loupe ( seiler loupes ) and a sharp dg 16 explorer was used to locate the canal orifice . after obtaining the canal patency , a # 10 k file ( dentsply , maillefer ) was precurved and inserted in a distolingual direction to traverse the canal bifurcation into the second root [ figure 2 ] .
a working length radiograph confirmed the presence of a single coronal canal bifurcating in the middle one third , and coinciding with the separation of the two roots .
the two canals exited in separate apical foramina located in the respective roots [ figure 3 ] .
cleaning and shaping of the canals was performed using crown - down technique under copious irrigation with 5.25% sodium hypochlorite solution .
after three days , the canals were obturated with cold , lateral compaction of gutta percha cones ( dentsply ) and zinc oxide eugenol sealer .
a post obturation radiograph was taken to evaluate the quality of obturation [ figure 4 ] .
files inserted to traverse and confirm the root canal configuration working length radiograph of the mandibular right first premolar in the patient in the case study , showing the presence of a single coronal canal bifurcating in the middle one third and coinciding with the separation of the two roots .
the canals exited in separate apical foramina in the respective root post - operative radiograph of the mandibular right first premolar in the patient in the case study
anatomical variations , especially extra canals and roots , should always be kept in mind when treating teeth endodontically .
canals if left unclean may harbour microorganisms , which have been reported to be a major cause for treatment failure .
a study at the university of washington assessed the failure rate of non surgical root canal therapy in all teeth .
the root morphology of mandibular first premolar can be highly complex and extra root(s ) can be found .
scott and turner describe the accessory root of mandibular first premolar as tome 's root .
they observed ethnic differences in the root morphology ; and , reported the highest incidence ( > 25% ) of accessory roots in the australian and sub saharan african populations .
the lowest incidence of tome 's root ( 0 - 10% ) occurred in the american , arctic , new guinea , jomon and western eurasian populations .
sert and bayrili also reported sex differences in canal morphology , reporting higher incidence ( 44% ) of accessory roots and canals in females as compared to males ( 34% ) .
thus , a variety of factors contribute to variations in root anatomy of mandibular first premolars . successful endodontic outcome in such cases is dependent upon careful use of all the available diagnostic aids to locate and treat the entire root canal system .
careful interpretation of angled radiographs , proper access preparation and a detailed exploration of the tooth are essential prerequisites for a successful treatment outcome .
Output:
| thorough knowledge of the root canal morphology , appropriate assessment of the pulp chamber floor , and critical interpretation of radiographs are a prerequisite for successful root canal therapy .
the possibility of additional root / canal should be considered even in teeth with a low frequency of abnormal root canal anatomy .
this article reports on a case of mandibular first premolar with two roots , which was successfully treated with root canal therapy . |
PubmedSumm118739 | ***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 seventies , dr . harald zur hausen firstly postulated the link between human papillomaviruses ( hpvs ) and cervical cancer : studies to develop an anticancer vaccine followed .
approximately 70% of cervical cancers worldwide are associated with two high - risk hpv types ( 16/18 ) [ 1 , 2 ] and almost 90% of genital warts are associated with two low - risk hpv types ( 6/11 ) .
each year around 500,000 women develop invasive cervical cancer worldwide , with 83% of new cases and 85% of deaths occurring in developing countries [ 3 , 4 ] .
risk factors associated with hpv infection are younger age at first coitus , higher number of sexual partners , smoking cigarettes , and history of herpes simplex virus infection [ 5 , 6 ] .
some 75% of sexually active women develop a hpv infection , more frequently soon after their sexual debut : the majority of these infections ( between 70% and 90% ) spontaneously clear [ 810 ] .
a minority progress from acute infection to cervical cancer , a process taking decades and going through precancerous lesions named cervical intraepithelial neoplasia ( cin ) of increasing severity , from cin1 to cin3 ; spontaneous regression of the lesions is possible at any point [ 4 , 8 ] .
incidence of genital warts is less precisely known , due to lack of data on the general population , but it is estimated to be around 1% . based on the results of five randomized controlled trials ( rcts ) involving 40,000 women [ 1117 ] two hpv vaccines entered the market .
the quadrivalent vaccine against hpv6/11/16/18 was approved by the fda and the ema in 2006 [ 18 , 19 ] , whereas the bivalent vaccine against hpv16/18 was first approved in europe in 2007 and then in the usa in 2009 .
soon after , several western countries such as the usa , australia , and five european states started national immunization campaigns targeting adolescent girls .
the number of countries adopting the vaccines has since increased : in april 2014 , 23 out of 29 european countries were reported to have implemented it , budgetary constraints being one relevant obstacle for the remaining countries .
the primary target of hpv vaccination is adolescent girls aged 11 to 13 years , with some minor differences in national recommendations : in the usa routine vaccination is recommended at age 11 or 12 years with quadrivalent or bivalent vaccine for females and with quadrivalent vaccine for males in a 3-dose schedule during a 6-month interval ; in the uk hpv vaccine is recommended for girls under 15 years of age and consists in two injections spaced at least six and not more than 24 months apart .
both vaccines contain human papillomavirus l1 self - assembling virus - like particles and are not infectious .
differences between the two vaccines are the number of hpv types included and formulation of the adjuvant ( table 1 ) possibly leading to different vaccine efficacy ( ve ) [ 3638 ] .
head - to - head comparisons between the two vaccines are still exclusively based on immunogenicity [ 38 , 39 ] , although an immune correlate of protection has not yet been established .
three meta - analyses , published when vaccines were marketed , showed comparably high efficacy of the two vaccines against precancerous lesions associated with hpv16/18 [ 30 , 41 , 42 ] .
the meta - analyses subsequently published [ 43 , 44 ] have confirmed the high efficacy of the vaccines against lesions associated with hpv16/18 , but they did not provide information about ve against any cervical lesions irrespective of hpv type , nor did they discuss possible differences in terms of efficacy of the two vaccines .
thus , our systematic review that includes studies with longer follow - up aims to assess differences between the two vaccines from a public health perspective , considering all cervical lesions .
the systematic review was developed based on a prespecified protocol ( protocol number farm8n2zfl ) funded by the italian medicines agency ( aifa ) within a program of independent research on drugs .
the prisma ( preferred reporting items for systematic reviews and meta - analyses ) statement guided the content and reporting of the review . published and unpublished rcts comparing any of the two hpv vaccines versus placebo or any other control were considered for inclusion .
we exclusively considered studies involving women , irrespective of age at enrolment . as for protocol , primary outcome measures were cervical lesions ( i.e. , cervical cancer , cin2 , cin3 , and ais ) associated with any hpv type and cervical lesions exclusively associated with hpv16/18 occurring in three study populations : according to protocol population ( atp ) , the general population of vaccinated women ( total vaccine cohort ( tvc ) ) approximating all women regardless of status of hpv infection at vaccination , and a selected population of women seronegative for hpv16/18 and hpv dna negative for 14 oncogenic hpv types , approximating the group of young adolescent girls targeted in the national immunization campaigns ( tvc - nave ) . in this paper only data related to cervical lesions associated with any hpv type occurring in the tvc and in the tvc - nave population are reported , as the other data are not relevant from a public health perspective .
trial identification : we searched the cochrane library ( to issue 3 , 2014 ) , medline ( to march 2014 ) , and embase ( to march 2014 ) using keywords and mesh terms as reported in annex 1 online , in combination with a highly sensitive filter for identifying rct .
reference lists of relevant papers were also examined to identify additional studies . for unpublished rcts , we searched the internet for prepublication study presentations at conferences or meetings .
moreover experts in the field and vaccine manufacturers were contacted for further information ( unpublished studies and single patient data ) .
two review authors independently screened abstracts of potential studies and retrieved full articles for those deemed eligible .
two reviewers carried out independent assessment of citations retrieved . when more than one publication reported the same trial , the one with a longer follow - up was selected .
quality of trials was assessed using the criteria outlined in the cochrane handbook and included the assessment of ( i ) generation of the randomization sequence , ( ii ) quality of the allocation concealment , ( iii ) completeness of follow - up , and ( iv ) blinding of the outcome assessment . based on quality assessment the risk of bias of the included trials was defined as low , high , or unclear .
to event data the hazard ratio ( hr ) was used as a measure of association .
the results were summarized by using the inverse of variance method and the random effects model .
point estimates as well as their 95% confidence intervals ( 95% ci ) were calculated and represented by the forest plot .
vaccine efficacy ( ve ) was calculated as ve(% ) = ( ru rv)/ru 100 , where ru is the rate of disease in the unvaccinated and rv is the rate in the vaccinated .
the equation can be rewritten to use the hr in the following way : ve(% ) = ( 1 hrv / u ) 100 , where hrv / u is the hr of the vaccinated versus the unvaccinated .
the following prespecified subgroup analyses were planned : geographical areas ( europe , africa , asia , north america , and south and central america ) : the literature suggests that prevalence and circulation of hpv high risk types varies according to geographical areas [ 4951].vaccine type ( bivalent , quadrivalent ) : data on ve can be influenced by type of vaccine used as differences between the two formulations could be not negligible .
geographical areas ( europe , africa , asia , north america , and south and central america ) : the literature suggests that prevalence and circulation of hpv high risk types varies according to geographical areas [ 4951 ] .
vaccine type ( bivalent , quadrivalent ) : data on ve can be influenced by type of vaccine used as differences between the two formulations could be not negligible .
study identification and selection process is outlined in figure 1 . of the 726 records initially identified , 3 were duplicates and 670 were excluded based on title and abstract assessment . the most common reasons for exclusion were the following : reports were not rcts , did not assess the outcome of interest , were not related to oncogenic hpv or to vaccine administration , or were studies reporting exclusively laboratory or immunogenicity data .
we assessed the full text of 53 articles and excluded 44 ( reasons reported in figure 1 ) .
thus nine reports [ 2629 , 3135 ] , corresponding to five registered protocols [ 5256 ] , were included in the systematic review : in three trials ( 20,797 women ) the bivalent vaccine was used ( patricia trial being the larger study ) [ 2729 ] and in two trials ( 17,622 women ) the quadrivalent vaccine was assessed ( future i and future ii trials ) .
five publications reporting subset of data of the above - mentioned trials relating to specific geographical areas were also included [ 3135 ] .
the data of the phase iii trials included in our meta - analysis have a mean follow - up of 4 years for the bivalent trial and 3.6 years for the quadrivalent trial , longer than that of the systematic reviews with meta - analysis published up to now
eligible participants were healthy , not pregnant women aged between 15 and 26 years , with 6 or less lifetime sexual partners and no history of abnormal pap smear at enrolment .
risk of bias was low in 4 out of 5 trials : generation of the randomization sequence , quality of allocation concealment , completeness of follow - up , and blinding of outcome assessment were adequate .
risk of bias was unclear ( generation of the randomization sequence and allocation concealment were not described ) in one smaller trial conducted in japan ; as the japanese trial provided only data on cin2 + lesions exclusively associated with hpv16/18 , its results are not reported here .
characteristics of the women enrolled in the trials used in this meta - analysis are reported in table 3 .
pooling of the data was possible for cin2 + [ 2628 ] , cin3 + [ 26 , 27 ] , and ais [ 26 , 28 ] .
data for each outcome are presented below for the tvc and the tvc - nave cohorts .
the pooled hrs for cin2 + lesions associated with any type of hpv in the tvc and in the tvc - nave are reported in figure 2 .
corresponding values of ve were 26% ( 95% ci : 11 , 39 ) in the tvc
[ 26 , 27 ] and 58% ( 95% ci : 35 , 72 ) in the tvc - nave [ 2628 ] .
results suggested substantial heterogeneity among bivalent and quadrivalent vaccines : i test was 68.7% and 66.4% in the tvc and in the tvc - nave , respectively .
the pooled hrs for cin3 + lesions associated with any type of hpv in the tvc and in the tvc - nave are reported in figure 3 .
corresponding values of ve were 32% ( 95% ci : < 0 , 56 ) in the tvc [ 26 , 27 ] and 78% ( 95% ci : < 0 , 97 ) in the tvc - nave [ 26 , 27 ] .
results suggested substantial heterogeneity among bivalent and quadrivalent vaccines : i test was 86.3% and 90.7% in the tvc and in the tvc - nave , respectively .
the pooled hr for lesions associated with any type of hpv was 0.31 ( 95% ci : 0.140.70 ) in the tvc [ 26 , 27 ] , corresponding values of ve being 69% ( 95% ci : 30 , 86 ) .
ais cases in the tvc - nave cohort were zero in the vaccine group and ten in the placebo ; thus only an approximate estimate of the efficacy was possible .
the pooled hr for lesions associated with any type of hpv was 0.01 ( 95% ci : 0.010.22 ) resulting in a ve of 99% ( 95% ci : 78 , 99 ) [ 26 , 27 ] .
although formally required by the scientific advisory unit of ecdc in stockholm , the two manufacturers did not provide single patient data ( the authors received only partial data unsuitable for the analysis from gsk and no answer at all from sanofi pasteur msd ) .
five published papers [ 3135 ] reported data according to geographical areas . pooling of the data was not appropriate since geographical areas definition differed ( table 4 ) .
since their introduction into the market , the effectiveness of the two vaccines against cervical cancer , based on first published data [ 1117 ] , has been subject of debate .
enthusiastic positions assumed that if vaccines are immunogenic and prevent infections associated with hpv16/18 they also prevent cervical cancer and therefore should be widely used [ 5759 ] .
uncertainty was related to the following issues : correlation between immune response and clinical outcomes , need for a booster dose , replacement with other oncogenic strains , and possible reduction of pap - test screening among the vaccinated [ 6065 ] .
our systematic review highlights that , for precancerous lesions ( cin ) , the only available proxy of cervical cancer and heterogeneity among pooled studies is substantial ( figures 2 and 3 ) : the bivalent vaccine shows higher efficacy against precancerous lesions .
we focus our comments on the tvc - nave cohort , as ve in the tvc is confirmed to be much lower and hpv vaccination is not universally offered to women already sexually active and data on ais are too sparse to make sensible comments
. for cin2 + lesions estimates of efficacy of the two vaccines in the tvc - nave cohort differ but the wide limits of the confidence intervals partially overlap ( ve 65% ; 95% ci : 54 , 74 for the bivalent and ve 43% ; 95% ci : 23 , 57 for the quadrivalent ) , whereas for cin3 + lesions estimates of efficacy largely differ and the limits of the confidence intervals do not overlap ( ve 93% ; 95% ci : 77 , 98 for the bivalent and ve 43% ; 95% ci : 12 , 63 for the quadrivalent ) .
however , due to limited number of patients with lesions detected , leading to wide confidence intervals of our estimates of effect , our conclusions should be interpreted with caution .
the heterogeneity observed might be due to higher efficacy of the bivalent vaccine against cervical cancer possibly related to the specific adjuvant used ( aso4 adjuvant system ) , as suggested in two recent immune response head - to - head studies that consistently showed a higher neutralizing antibody production [ 38 , 39 ] and a higher cd4 + t cell response in bivalent than in quadrivalent vaccine recipients .
heterogeneity can also be due to baseline differences between the populations enrolled in the two trials , although such differences were not reported in the two trials ( table 3 ) .
however , misclassification of nave women can not be ruled out since the two manufacturers used different laboratory tests to measure immune response and to identify nave girls .
in fact clia test was used in the future trials whereas elisa test that has a higher sensitivity than clia was used in the patricia trial .
moreover , data are often differently and poorly reported in the published trials [ 2629 , 3135 ] ; thus our ability to make meaningful comparisons and further analysis ( e.g. , assess the possible effect modification by smoking status or age ) is hindered .
we asked the manufacturers to provide individual patient data , but we did not receive a positive answer .
another relevant point is that the length of the follow - up in the trials assessed seems insufficient to detect information relevant to the public and to policy - makers : as time interval from hpv infection to cervical cancer development is approximately 20 years , all information gathered in a much shorter period of time is not conclusive .
nevertheless the patricia trial has a planned follow - up of 4 years and longer follow - up data on bivalent vaccine are only available for 436 brazilian women enrolled in a previous phase ii trial .
we will have more information in 2020 , when the results of the finnish study that extended the follow - up for finnish girls enrolled in the patricia study will be published and when the extension studies for the future ii trial assessing the quadrivalent vaccine will also be available . in the meantime
an open debate in this respect is urgently needed : national health agencies should set up a surveillance system to provide data on actual vaccines efficacy in the field and to allow international comparisons .
at the moment , this comparison is not possible and we still do not know how to choose between the two vaccines .
contrary to what is previously reported in other meta - analyses [ 30 , 4144 ] , our systematic review suggests that the quadrivalent and the bivalent vaccines differ in terms of efficacy .
for example , in italy hpv vaccines are chosen and purchased through tendering schemes organized by regional health authorities that are based on the lowest price .
apart from cervical cancer prevention , quadrivalent vaccine is known to effectively prevent genital warts [ 71 , 72 ] , whereas the bivalent vaccine can only marginally impact on these benign but distressing lesions .
the uk and a few italian regions have recently substituted the bivalent with the quadrivalent vaccine , assuming comparable efficacy of the two vaccines against cervical cancer and giving an additional value to the activity against genital warts of the quadrivalent vaccine [ 10 , 74 ] .
unfortunately , it is not possible to anticipate the consequences of the uk 's and italian choice : if different vaccine efficacy of the bivalent and the quadrivalent vaccine is going to be confirmed , lack of equivalence in terms of cervical cancer prevention could become an issue .
the availability in the coming years of new broader spectrum hpv prophylactic vaccines could provide more insight into the current debate [ 75 , 76 ] .
in conclusion , we acknowledge that this systematic review has some limitations due to a low number of women with events and a high heterogeneity among trials that suggest caution in the interpretation of results . however , our conclusions are consistent with those from recent immunogenicity head - to - head studies [ 38 , 39 ] and that provides strength to our interpretation .
our systematic review suggests that after nine years since hpv vaccines were introduced , their estimates of efficacy seem to diverge over time .
the decision to consider the two vaccines similar in terms of cervical cancer prevention seems challenged by our longer term follow - up analyses .
this might have implications for policy and pragmatic choices and deserves an open and comprehensive discussion .
moreover , international comparisons of the actual effectiveness of the two vaccines used in the field can add valuable information .
finally , regulatory agencies should encourage the pharmaceutical companies to provide data across trials to assess all relevant outcomes in a comparable way , to reduce uncertainty , and to support health policy - makers that have to choose between alternative options [ 77 , 78 ] .
Output:
| background .
when the bivalent and the quadrivalent hpv vaccines were marketed they were presented as having comparable efficacy against cervical cancer .
differences between the vaccines are hpv types included and formulation of the adjuvant . method .
a systematic review was conducted to assess the efficacy of the two vaccines against cervical cancer .
outcomes considered were cin2 + , cin3 + , and ais .
results .
nine reports ( 38,419 women ) were included .
at enrolment mean age of women was 20 years , 90% had negative cytology , and 80% were seronegative and/or dna negative for hpv 16 or 18 ( nave women ) . in the tvc - nave ,
ve against cin2 + was 58% ( 95% ci : 35 , 72 ) ; heterogeneity was detected , ve being 65% ( 95% ci : 54 , 74 ) for the bivalent and 43% ( 95% ci : 23 , 57 ) for the quadrivalent .
ve against cin3 + was 78% ( 95% ci : < 0 , 97 ) ; heterogeneity was substantial , ve being 93% ( 95% ci : 77 , 98 ) for the bivalent and 43% ( 95% ci : 12 , 63 ) for the quadrivalent .
ve in the tvc was much lower .
no sufficient data were available on ais .
conclusions . in nave girls
bivalent vaccine shows higher efficacy , even if the number of events detected is low . in women
already infected the benefit of the vaccination seems negligible . |
PubmedSumm118740 | ***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: chronic obstructive pulmonary disease ( copd ) , a lung disease characterized by airflow limitations that are not fully reversible , is a major cause of chronic morbidity and mortality worldwide.13 the global burden of disease study predicted that copd is predicted to rise from the sixth most common cause of mortality worldwide , to the third most common cause of mortality in 2020.4 additionally , with the aging of the population , the burden of copd is increasing continuously.57 however , recent data likely underestimate the total burden of copd because the disease is usually not diagnosed until it is clinically apparent and already moderately advanced.8 although copd is primarily a pulmonary disease associated with an abnormal inflammatory response in the lungs , copd is also associated with a certain degree of systemic inflammation , which has been correlated with adverse clinical effects.911 several studies have reported potential associations between oral health and respiratory diseases , including copd.1214 scannapieco and mylotte15 suggested that periodontal disease might change oral microbiological conditions and permit mucosal colonization and infection by respiratory pathogens.15 additionally , oral health is likely to interact with other cofactors ( eg , smoking , environmental pollutants , infection , allergy , genetic factors ) that are also important in copd patients.16 among indicators of oral health , the number of natural teeth can be rapidly and easily determined in the clinic .
ztekin et al17 reported that the number of teeth was significantly lower in copd patients .
barros et al11 reported that edentulous copd patients were at greater risk of having a copd - related event ( hospitalization and death ) .
the aim of this study was to investigate the association between the number of natural teeth and airflow obstruction , which is a central feature of copd , by analyzing data from the korean population .
data were collected from the korean national health and nutrition examination survey ( knhanes ) , which was performed by the korean centers for disease control and prevention ( korean ministry of health and welfare ) in 2012.18 knhanes has been conducted regularly since 1998 to monitor the general health and nutritional status of the civilian , noninstitutionalized south korean population .
participants were selected using proportional allocation - systemic sampling with multistage stratification to produce a nationally representative sample of the resident , civilian korean population .
knhanes comprised three sections : a health interview survey , a health examination , and a nutrition survey.18 additional details about the knhanes have been provided elsewhere.18 among participants in the survey in 2012 , this current study analyzed participants over 40 years who underwent reliable spirometry and oral health assessments ( n=3,089 ; 1,291 males and 1,798 females ) .
this current study was approved by the institutional review board of seoul st mary s hospital .
the institutional review board of seoul st mary s hospital did not require patient consent for this present study because all participants gave their consent for the knhanes before the registration , and the knhanes data is open to the public after being anonymized .
height , weight , and waist circumference ( wc ) were measured with standard procedures .
wc was measured at the midpoint of the lower margin of the 12th rib and the iliac crest in the midaxillary line at the end of expiration .
weight was measured to the nearest 0.1 kg and body mass index ( bmi ) was calculated as weight in kilograms divided by height in meters squared .
all participants were asked about their demographic characteristics , socioeconomic characteristics , and medical history . trained interviewers performed the interviews using structured questionnaires .
subjects were considered as ever smokers if they had smoked > 100 cigarettes in their lifetime .
the amount of alcohol consumed ( in g / day ) was calculated using the average number of alcoholic beverages ingested and frequency of drinking .
monthly income was standardized according to the number of family members ( monthly income/number of family members ) and was divided into four quartile groups : lowest , lower middle , higher middle , and highest ( table s1 ) .
education level was classified as high , if the subjects finished high school education or more ( higher than 12th grade ) .
geographic regions were classified as rural ( gangwon , chungbuk , chungnam , jeonbuk , jeonnam , gyeongbuk , gyeongnam , and jeju ) or urban ( seoul , busan , daegu , daejeon , gwangju , incheon , ulsan , and gyeonggi ) areas .
regular exercise was defined as strenuous physical activity performed for at least 20 minutes at a time at least three times per week .
the nutrition surveys included questions about the participant s eating pattern , use of dietary supplements , knowledge of nutrition , and food intake using the 24 hours recall method
. the total energy intake and the percentage of energy from each nutrient ( fat , carbohydrate , and protein ) were then calculated .
diabetes mellitus ( dm ) was defined as a fasting glucose level 126 mg / dl , the current use of antidiabetic medications , or a self - reported physician diagnosis of dm .
metabolic syndrome was defined using the diagnostic guidelines from the american heart association and the national heart , lung , and blood institute.19 vitamin d is well known for its crucial role in bone homeostasis .
vitamin d showed significant association with pulmonary function , periodontitis , and tooth loss as seen from other studies.20,21 vitamin d level was measured with a 1470 wizard -counter ( perkin - elmer , turku , finland ) using a radioimmunoassay .
licensed trained technicians measured the forced vital capacity ( fvc ) , forced expiratory volume in 1 second ( fev1 ) , and the fev1/fvc ratio using a dry rolling seal spirometer ( model 2130 ; sensormedics , yorba linda , ca , usa ) .
a quality - control program was performed ; the spirometer was calibrated every morning before performing spirometry ( and recalibrated every time the room temperature changed by 3c ) , and the american thoracic society / european respiratory society criteria of acceptability and repeatability were followed by the examiners on site .
variables used to predict normal values included age , sex , height , and ethnicity.22 spirometry results were classified as normal , restrictive , and obstructive pattern .
subjects with fev1/fvc 70% and fvc 80% of the normal predicted value were considered normal.23,24 when fev1/fvc 70% and fvc was under 80% of the normal predicted value , the subjects were classified as restrictive pattern . obstructive pattern , which we considered to have airflow obstruction in this study , was defined with fev1/fvc < 70% .
the severity of airflow obstruction was based on the percentage of normal predicted prebronchodilator fev1 . the knhanes 2012 oral health data recorded the status for each of the 32 teeth . in this study , total number and pairs of natural teeth
based on this information , we categorized the subjects into three groups according to total numbers of natural teeth : full dentition ( 28 teeth ) , 2027 teeth , and fewer than 20 teeth .
we also classified the subjects into one of three groups according to pairs of natural teeth .
the world health organization community periodontal index ( cpi ) was used to assess periodontitis and when cpi code 3 , we deemed this to be periodontitis.25,26 code 3 indicates that at least one site had a > 3.5 mm pocket in the index teeth , which are 2 , 3 , 8 , 14 , 15 , 18 , 19 , 24 , 30 , and 31 , according to the universal numbering system , which has been adopted by the american dental association .
a cpi probe , which is appropriate for the world health organization guidelines , was used .
we also checked the number of tooth brushings and the use of secondary oral products for assessing oral health behavior .
number of tooth brushings was categorized as once , twice , and three or more times per day .
secondary oral products included mouthwash , dental floss , water flosser , an interdental brush , and an electric toothbrush .
all data were presented as mean standard error for continuous variables or as proportions ( standard error ) for categorical variables .
statistical analyses were performed with the sas survey procedure ( ver 9.3 ; sas institute , inc . ,
cary , nc , usa ) to reflect the complex sampling design and sampling weights of knhanes and to provide nationally representative prevalence estimates .
the test was used with categorical variables and a one - way analysis of variance with continuous variables .
we used analysis of covariance to compare the number and pairs of the natural teeth according to lung function after adjusting for potential confounders .
multivariate logistic regression analyses were performed to estimate the association of airflow obstruction and the number of natural teeth .
odds ratio ( or ) and 95% confidence intervals ( cis ) were estimated after adjustment for potential confounders . in the multivariate analyses for the number and pairs of natural teeth , we first adjusted for age ( model 1 ) and then adjusted for the variables in model 1 plus smoking , drinking , exercise , income , education , and bmi ( model 2 ) . finally , model 3 adjusted for the variables in model 2 plus periodontitis , number of tooth brushings , and the use of secondary oral products .
data were collected from the korean national health and nutrition examination survey ( knhanes ) , which was performed by the korean centers for disease control and prevention ( korean ministry of health and welfare ) in 2012.18 knhanes has been conducted regularly since 1998 to monitor the general health and nutritional status of the civilian , noninstitutionalized south korean population .
participants were selected using proportional allocation - systemic sampling with multistage stratification to produce a nationally representative sample of the resident , civilian korean population .
knhanes comprised three sections : a health interview survey , a health examination , and a nutrition survey.18 additional details about the knhanes have been provided elsewhere.18 among participants in the survey in 2012 , this current study analyzed participants over 40 years who underwent reliable spirometry and oral health assessments ( n=3,089 ; 1,291 males and 1,798 females ) .
this current study was approved by the institutional review board of seoul st mary s hospital .
the institutional review board of seoul st mary s hospital did not require patient consent for this present study because all participants gave their consent for the knhanes before the registration , and the knhanes data is open to the public after being anonymized .
height , weight , and waist circumference ( wc ) were measured with standard procedures .
wc was measured at the midpoint of the lower margin of the 12th rib and the iliac crest in the midaxillary line at the end of expiration .
weight was measured to the nearest 0.1 kg and body mass index ( bmi ) was calculated as weight in kilograms divided by height in meters squared .
all participants were asked about their demographic characteristics , socioeconomic characteristics , and medical history . trained interviewers performed the interviews using structured questionnaires .
subjects were considered as ever smokers if they had smoked > 100 cigarettes in their lifetime .
the amount of alcohol consumed ( in g / day ) was calculated using the average number of alcoholic beverages ingested and frequency of drinking .
monthly income was standardized according to the number of family members ( monthly income/number of family members ) and was divided into four quartile groups : lowest , lower middle , higher middle , and highest ( table s1 ) .
education level was classified as high , if the subjects finished high school education or more ( higher than 12th grade ) .
geographic regions were classified as rural ( gangwon , chungbuk , chungnam , jeonbuk , jeonnam , gyeongbuk , gyeongnam , and jeju ) or urban ( seoul , busan , daegu , daejeon , gwangju , incheon , ulsan , and gyeonggi ) areas .
regular exercise was defined as strenuous physical activity performed for at least 20 minutes at a time at least three times per week .
the nutrition surveys included questions about the participant s eating pattern , use of dietary supplements , knowledge of nutrition , and food intake using the 24 hours recall method .
the total energy intake and the percentage of energy from each nutrient ( fat , carbohydrate , and protein ) were then calculated .
diabetes mellitus ( dm ) was defined as a fasting glucose level 126 mg / dl , the current use of antidiabetic medications , or a self - reported physician diagnosis of dm .
metabolic syndrome was defined using the diagnostic guidelines from the american heart association and the national heart , lung , and blood institute.19 vitamin d is well known for its crucial role in bone homeostasis .
vitamin d showed significant association with pulmonary function , periodontitis , and tooth loss as seen from other studies.20,21 vitamin d level was measured with a 1470 wizard -counter ( perkin - elmer , turku , finland ) using a radioimmunoassay .
licensed trained technicians measured the forced vital capacity ( fvc ) , forced expiratory volume in 1 second ( fev1 ) , and the fev1/fvc ratio using a dry rolling seal spirometer ( model 2130 ; sensormedics , yorba linda , ca , usa ) .
a quality - control program was performed ; the spirometer was calibrated every morning before performing spirometry ( and recalibrated every time the room temperature changed by 3c ) , and the american thoracic society / european respiratory society criteria of acceptability and repeatability were followed by the examiners on site .
variables used to predict normal values included age , sex , height , and ethnicity.22 spirometry results were classified as normal , restrictive , and obstructive pattern .
subjects with fev1/fvc 70% and fvc 80% of the normal predicted value were considered normal.23,24 when fev1/fvc 70% and fvc was under 80% of the normal predicted value , the subjects were classified as restrictive pattern . obstructive pattern , which we considered to have airflow obstruction in this study , was defined with fev1/fvc < 70% .
the severity of airflow obstruction was based on the percentage of normal predicted prebronchodilator fev1 .
the knhanes 2012 oral health data recorded the status for each of the 32 teeth . in this study , total number and pairs of natural teeth were counted after excluding third molars . based on this information , we categorized the subjects into three groups according to total numbers of natural teeth : full dentition ( 28 teeth ) , 2027 teeth , and fewer than 20 teeth .
we also classified the subjects into one of three groups according to pairs of natural teeth .
the world health organization community periodontal index ( cpi ) was used to assess periodontitis and when cpi code 3 , we deemed this to be periodontitis.25,26 code 3 indicates that at least one site had a > 3.5 mm pocket in the index teeth , which are 2 , 3 , 8 , 14 , 15 , 18 , 19 , 24 , 30 , and 31 , according to the universal numbering system , which has been adopted by the american dental association .
a cpi probe , which is appropriate for the world health organization guidelines , was used .
we also checked the number of tooth brushings and the use of secondary oral products for assessing oral health behavior .
number of tooth brushings was categorized as once , twice , and three or more times per day .
secondary oral products included mouthwash , dental floss , water flosser , an interdental brush , and an electric toothbrush .
all data were presented as mean standard error for continuous variables or as proportions ( standard error ) for categorical variables .
statistical analyses were performed with the sas survey procedure ( ver 9.3 ; sas institute , inc . , cary , nc , usa ) to reflect the complex sampling design and sampling weights of knhanes and to provide nationally representative prevalence estimates .
the test was used with categorical variables and a one - way analysis of variance with continuous variables .
we used analysis of covariance to compare the number and pairs of the natural teeth according to lung function after adjusting for potential confounders .
multivariate logistic regression analyses were performed to estimate the association of airflow obstruction and the number of natural teeth .
odds ratio ( or ) and 95% confidence intervals ( cis ) were estimated after adjustment for potential confounders . in the multivariate analyses for the number and pairs of natural teeth , we first adjusted for age ( model 1 ) and then adjusted for the variables in model 1 plus smoking , drinking , exercise , income , education , and bmi ( model 2 ) . finally , model 3 adjusted for the variables in model 2 plus periodontitis , number of tooth brushings , and the use of secondary oral products .
all subjects were categorized into three groups ( normal , restrictive , and obstructive ) according to their pulmonary function test . among the total population , 12.9% had obstructive lung function , 10.0% had restrictive lung function , and 77.2% had normal lung function .
difference between males and females was 20.1% versus 6.0% , 8.9% versus 11.0% , and 71.0% versus 83.0% for obstructive , restrictive , and normal lung function , respectively .
there were significant differences among the three groups in age ( p<0.001 , both ) , height ( p<0.001 and p=0.017 , respectively ) , weight ( p<0.001 , both ) , bmi ( p<0.001 , both ) , and wc ( p<0.001 and p=0.002 , respectively ) in males and females . the obstructive group was older and had lower weight and bmi .
in socioeconomic characteristics , there were significant differences in income ( p<0.001 , both ) and education ( p<0.001 , both ) in males and females .
the obstructive group showed lower income and education than the other groups . in males ,
the obstructive group showed significantly more smokers ( p=0.040 ) , less exercise ( p=0.042 ) , and total energy ( p=0.041 ) .
although the amount of total energy was smaller in the obstructive group in females , the difference was of borderline significance ( p=0.054 ) .
dm ( p=0.003 and p=0.002 ) and metabolic syndrome ( p<0.001 , both ) were significantly more frequent in the restrictive group ( males and females ) .
vitamin d levels were significantly higher in the obstructive group in males ( p=0.005 ) . in terms of oral health , number of natural teeth was significantly lower in the obstructive group in males and females ( p<0.001 , both ) .
periodontitis index , number of tooth brushings , and use of secondary oral products showed no significant difference in the three groups . in both males and females , the proportion of participants with full dentition and all pairs of natural teeth tended to decrease in the order normal , restrictive , and obstructive group ( figure 1a and b ) .
the proportion of individuals who had fewer than 20 natural teeth or fewer than 10 pairs of natural teeth showed a reverse pattern , in both males and females .
we adjusted for variables that might influence the association between total number of natural teeth and lung function ( table 2 ) . after adjusting for age , bmi , socioeconomic status ( smoking , drinking , exercise , income , education ) , and oral health indexes ( periodontitis , number of tooth brushings , and use of secondary oral products )
, the obstructive group showed significantly fewer natural teeth than the other groups in males ( p=0.014 and p=0.008 for total number and total pairs of natural teeth , respectively ) .
there was no significant difference after adjustment in females in the total number or pairs of natural teeth .
the subjects were divided into three groups according to the total number ( < 20 , 2027 , 28 ) and pairs ( < 10 , 1013 , 14 ) of natural teeth ( table 3 ) . after adjusting for age , bmi , socioeconomic status , and oral health indexes
, ors for airflow obstruction were 4.18 ( 95% ci = 2.068.49 ) and 3.21 ( 95% ci = 1.855.58 ) in the groups with total numbers of teeth below 20 and 2027 , respectively .
the adjusted or for airflow obstruction of total pairs of natural teeth was 4.74 ( 95% ci = 2.349.62 ) and 3.08 ( 95% ci = 1.795.32 ) in the groups with total pairs of teeth below 10 and 1013 , respectively .
there was no significant relationship between the number or pairs of natural teeth and airflow obstruction in females .
figure 2 shows the trend of fev1 with subgroups of the number of natural teeth in patients with airflow obstruction . in both sexes ,
fev1 showed a decreasing trend in the groups with 2027 teeth and < 20 teeth compared with the 28-teeth group after adjustment for confounding factors ( age , smoking , drinking , exercise , income , education , and bmi ) .
although our study is a cross - sectional study using the results of prebronchodilator spirometry , we detected a statistically significant association between the number or pairs of natural teeth and airflow obstruction in males , even after adjusting for other variables such as age , bmi , socioeconomic factors ( smoking , drinking , exercise , income , education ) , and oral health factors ( periodontitis , number of tooth brushings , use of secondary oral products ) .
the adjusted or for airflow obstruction in males with fewer than 20 natural teeth was 4.18 ( 2.068.49 ) and that in males with fewer than 10 pairs of natural teeth was 4.74 ( 2.349.62 ) .
however , there was no significant association between the number or pairs of natural teeth and airflow obstruction in females . within patients with airflow obstruction ,
however , there was no statistically significant relationship between the number of natural teeth and percentage of normal predicted fev1 .
previous studies have suggested an association between airflow obstruction , which is a central feature of copd , and poor oral health.12,16,2730 scannapieco et al12 investigated the association between oral conditions and respiratory disease using data from the national health and nutrition examination survey i.12 subjects with maximum oral hygiene index values were 4.5-fold more likely to have a chronic respiratory disease than those with an oral hygiene index of 0 in their study .
hayes et al28 investigated the association between copd and periodontal disease , assessed by radiographic alveolar bone loss .
they showed that increased alveolar bone loss was associated with an increased risk of copd .
a case control study with 581 copd cases and 438 non - copd controls was performed by si et al27 in a chinese population .
the results showed a strong association between periodontitis and copd , and plaque index was a major periodontal factor for predicting copd ( or = 9.01 , 95% ci = 3.9820.4 ) .
although oral conditions likely work in concert with other factors and the underlying biological mechanisms still remain obscure,16 several mechanisms were suggested in these various studies to explain the association of copd with poor oral health .
aspiration of oral pathogens into the lower respiratory tract was one of these hypotheses.31 periodontal disease - associated enzymes in saliva may also change respiratory environmental conditions , permitting mucosal colonization and infection by respiratory pathogens.15,28,31 in addition , the association between poor oral health and respiratory disease was suggested to be mediated through systemic inflammatory responses.9,32 inflammatory cytokines , such as interleukin ( il)-6 or il-8 , from periodontal tissues may alter the respiratory epithelium to promote infection by respiratory pathogens.16 from other studies , tooth loss or less frequently brushing teeth was associated with an increased serum level of c - reactive protein.3335 levels of inflammatory biomarkers such as c - reactive protein and il-6 also have been reported to be elevated in copd.11 in this study , we used the number of natural teeth as a measure of oral health . rather than actually investigating oral hygiene or the presence of periodontitis , the number of natural teeth is a rapid and easy index for both clinicians and patients .
changes in oral health status due to caries and periodontitis lead to a reduced number of teeth.36 additionally , kressin et al37 showed that many oral health behaviors , including brushing , flossing , and prophylactic dental visits , can help retain a greater number of natural teeth.37 in our al products .
we believe that the cumulative effects of diverse oral health factors are reflected in the number of teeth .
we used pairs of natural teeth as a marker to reflect dental function , such as biting and chewing . in several other studies , functional units , defined as any opposing natural or prosthetic tooth pair ,
were used to account for the functional arrangement of the teeth.3840 from our results , both number and pairs of natural teeth showed an almost identical correlation with airflow obstruction .
males who had low numbers or pairs of teeth showed a stronger relationship with airflow obstruction .
in both sexes , patients with airflow obstruction tended to have the following characteristics : older in age , lower bmi , lower income , and less education .
subjects with restrictive lung patterns showed higher bmi , wc , and presence of dm and metabolic syndrome in both males and females .
however , only male subjects with airflow obstruction comprised a significantly greater number of smokers , partook in less exercise , and had a lower total energy intake . this difference may be because korean females in the general population traditionally have a low smoking rate , exercise , and total energy intake .
contrary to our expectations , levels of vitamin d were significantly higher in males with airflow obstruction .
several studies have reported a high prevalence of vitamin d deficiency in copd patients.4144 this may be explained by the nature of the study population .
all study groups showed vitamin d deficiency ( < 20 ng / ml ) regardless of lung function , and the group with airflow obstruction consisted mostly of mild cases .
after adjustments , the number or pairs of teeth were significantly related to airflow obstruction only in males . in females , other confounding factors , such as hormonal effects and the frequency of dental checkups , which were not considered in this study ,
additionally , the relationship between the number of natural teeth and airflow obstruction in females according to the severity of airflow obstruction should be compared in further studies .
using the results of prebronchodilator spirometry for diagnosing copd may overestimate the number of copd patients .
therefore , we defined the obstructive pattern of spirometry as airflow obstruction instead of copd .
second , the study was of a cross - sectional design and so no cause effect relationship could be determined .
third , this study involved healthy patients with mild airflow obstruction rather than those with severe airflow obstruction .
knhanes data were obtained from subjects participating in a nationwide survey ; individuals who were admitted to hospitals or nursing homes were not included . within these limitations ,
the knhanes data represent the public health of the total population of korea and is of considerable value in many respects.45 despite these limitations , there are several strengths in our study .
first , the number of teeth and oral condition was objectively assessed by dentist with same criteria .
in addition , several physical examinations and important confounding variables were also precisely recorded by trained examiners .
second , our study included a large number of participants who represent the korean population .
third , we used the number of natural teeth , which is a convenient index and reflects the cumulative effects of oral health .
loss of natural teeth was significantly associated with the presence of airflow obstruction in korean males . based on our results ,
the number of natural teeth could be one of the available indices for obstructive lung diseases , including copd .
further investigations are needed to clarify the relationship and mechanism between the oral health and obstructive lung diseases .
standard of monthly household income * ( us dollar ) notes : data from the korean national health and nutrition examination survey ( knhanes ) , 2012.18 the korean national health and nutrition examination survey provides the value of monthly income after standardization according to the number of family members .
Output:
| backgroundpotential associations between oral health and respiratory disease , including chronic obstructive pulmonary disease ( copd ) , have been suggested in several studies . among the indicators reflecting oral health ,
the number of natural teeth is an integrated and simple index to assess in the clinic . in this study
, we examined the relationship between the number of natural teeth and airflow obstruction , which is a central feature of copd.methodsa total of 3,089 participants over 40 years , who underwent reliable spirometry and oral health assessments were selected from the korean national health and nutrition examination survey 2012 , a cross - sectional and nationally representative survey .
spirometry results were classified as normal , restrictive , or obstructive pattern .
total number and pairs of natural teeth were counted after excluding third molars.resultsafter adjusting for other variables , such as age , body mass index , socioeconomic factors , and oral health factors , the group with airflow obstruction showed significantly fewer natural teeth than the other groups in males ( p=0.014 and 0.008 for total number and total pairs of natural teeth , respectively ) . compared with participants with full dentition ,
the adjusted odds ratio for airflow obstruction in males with fewer than 20 natural teeth was 4.18 ( 95% confidence interval : 2.068.49 ) and with fewer than 10 pairs of natural teeth was 4.74 ( 95% confidence interval : 2.349.62 ) .
however , there was no significant association between the total number or pairs of natural teeth and airflow obstruction after adjustment in females.conclusionsloss of natural teeth was significantly associated with the presence of airflow obstruction in males .
our finding suggests that the number of natural teeth could be one of the available indices for obstructive lung diseases , including copd . |
PubmedSumm118741 | ***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 pressure ulcer is an area of localized damage to the skin and underlying tissue caused by pressure , shear , or friction or by a combination of these ( european pressure ulcer advisory panel ) .
the reported incidence varies from 1.525% in long - term care facilities and can be as high as 70% in bed - ridden elderly population .
it remains a major cause of morbidity in the terminally ill and bedridden patients and a major cause of physical , psychosocial , and financial distress for the caregivers .
here , we describe the innovative and holistic model of management of pressure sores in a patient with motor neuron disease in a resource - constrained setting .
ps is a 52-year male with a diagnosis of motor neuron disease ( mnd ) and has been bedridden since last 7 months [ figure 1 ] .
his symptoms started 2 years back with a sudden onset of tingling in his arms followed by weakness that was irreversible .
he was diagnosed as a case of progressive muscular atrophy ( pma ) at a neurosciences centre .
note the wasting of the muscles of the shoulder girdle he is currently bedridden and can not sit - up without support and totally dependent on his wife , who is the primary care provider .
he was fully conscious , oriented , and co - operative and was distressed by pain in his lower back .
he also appeared to be depressed and was saddened that he was a burden to his family .
he was not on any drug therapy currently , although he had been advised therapy with riluzole , which he could not afford .
we gently probed for evidence of other concerns and assured him that we could provide symptomatic relief to him and accepted that we could not cure his disease .
we asked for his co - operation in the care process and outlined our management strategy to him , to which he accepted .
an examination revealed a grade - iii pressure sore 4 cm 5.5 cm , overlying the sacrum with malodour , local inflammation , significant serous exudation , and edema of the surrounding skin [ figure 2 ] .
he however was constipated and could not turn side - to - side without support .
his wife reported that the sore was there since last 2 months and had gradually increased in size and depth .
focused questioning revealed that she changed his posture twice in a day and cleaned the affected area with water from a tube well .
our hospice not having any access to funding could not provide him with dressing material ; however , we could provide him with some medications that we had received as
this was a resource constrained setting situated in a remote location and posed a challenge .
note the eschar ; it can prevent accurate grading of the ulcer we discussed the natural history of pma amongst our team ( emphasizing the importance of a multidisciplinary team approach in care ) and learnt that it affected 57% of people suffering from mnd , primarily affected the lower motor neurons , was progressive with an onset age of below 50 years and had a life expectancy of 510 years .
we learnt of the symptoms such as progressive weakness , loss of muscle bulk , fatigue , fasciculations , loss of reflexes , etc .
the management strategy is mainly nonpharmacological and centers around physiotherapy , optimizing pulmonary function , feeding , care of bladder , bowel , and skin .
we learnt about the diagnostic tests in addition to clinical diagnosis , being nerve conduction studies and electromyography .
we were also made aware of the possibility of the need of future interventions for feeding like a feeding tube or a percutaneous endoscopic gastrostomy ( peg ) and the possible future need for long - term ventilation at home .
we discussed the management plan with our team members keeping the prognosis , financial , and resource availability factors in mind .
our management plan began with educating and empowering the care - provider in the care process .
we stressed upon the importance of physiotherapy for ps and taught his wife how to perform passive range of movements of his joints .
we also highlighted the importance of skin care and advised her to give him a daily massage with groundnut oil , which was locally available .
we assured the care - providers that this was not a communicable disease and thus removed the stigma associated with the disease and encouraged visitors .
we taught his wife to use cut pieces of linen and boil them in a covered utensil prior to using them for wound dressings ( they did not have a pressure cooker ) .
we suggested her to use raw papaya paste for wound debridement till healthy slough was visible .
raw papaya has papain that has exfoliating properties , and can remove dead cells effectively .
this advice was given as we did not have access to facilities for surgical debridement at that point of time .
she was advised to use preboiled and cooled water ( 1 l ) to which one pinch of salt was to be added , thus preparing normal saline .
she was also advised to use turmeric paste to dress the wounds after applying it on a clean piece of linen .
recommended cleaning solutions are sterile water or normal saline ( level - iii evidence ) as disinfectants are toxic to tissues and can impair healing ( level - ii evidence ) .
we taught his wife the importance of frequent change of posture , preferably 2 hourly , to reduce interface pressure .
they could not afford mattresses and hence stress was given on frequent change of posture .
in addition , advice was given to avoid shear and friction forces as far as practicable while changing sheets or clothes of the patient .
we also taught them to pad bony prominences such as sacrum , elbows , greater trochanter , heels , which were particularly prone to pressure sore .
we also taught them about the importance of preventing secondary infection as that would prevent healing , aggravate the wound and could lead to septicaemia and death .
we also highlighted the importance of nutrition and supplementation with vitamins and minerals in prevention and healing of the sores .
we stressed on intake of zinc - enriched food such as peanuts , pumpkin , and watermelon seeds , etc . because of their positive effects on wound healing ( www.healthaliciousness.com/articles/zinc.php ) .
ps could swallow but was anorexic , probably resulting from his constipation , which was compounded by his immobility .
we advised that he should take plenty of water and fluids along with isabol husk that was available locally .
we understand that a stimulant laxative like bisacodyl would have been appropriate combined with a stool softener .
however , we only had access to isabol at that point of time and we suggested its use with adequate potassium supplementation .
we also suggested that he should consume bananas and coconut water ( which is rich in potassium and good for gut motility ) , both of which were available in plenty locally .
ps also had significant pain and of a burning nature in his lower back and appeared distressed .
we used the s - lanss ( self - report version of leeds assessment of neuropathic symptoms and signs ) questionnaire in the interview format , which revealed that he had neuropathic pain as well .
he also had difficulty in sleeping at night and was saddened that his wife no longer slept with him .
we gently brought up the issue with his wife and suggested that they talk about it .
we did not consider it appropriate to dive into the issue in detail in our first visit and also to respect the social and cultural issues .
( 500 mg ) , metronidazole ( 400 mg ) , ciprofloxacin ( 500 mg ) , and amitrytiline tablets ( 25 mg ) , which we gave him with instructions for .
his wife was advised to give him a daily bath before wound dressing , followed by topical application of lignocaine gel on the sore and one tablet of paracetamol 20 min prior to change of dressings .
in addition , amitryptiline 25 mg and paracetamol 500 mg were to be given at bedtime .
if we had been afforded the luxury , we would have started him on extended release tramadol ( 100 mg ) given at bed time , thereby ensuring good and pain - free sleep and reviewing his status after a couple of days to guide further therapy .
amitriptyline would act by its sedative , antidepressant and analgesic properties ( for neuropathic pain ) .
amitriptyline acts primarily by inhibiting the reuptake of noradrenaline and serotonin in the descending inhibitory pathways in the spinal cord , thus potentiating analgesia .
we advised that metronidazole tablets be crushed and applied topically on the ulcer to reduce malodour as we suspected anaerobic infection .
our management plan began with educating and empowering the care - provider in the care process .
we stressed upon the importance of physiotherapy for ps and taught his wife how to perform passive range of movements of his joints .
we also highlighted the importance of skin care and advised her to give him a daily massage with groundnut oil , which was locally available .
we assured the care - providers that this was not a communicable disease and thus removed the stigma associated with the disease and encouraged visitors .
we taught his wife to use cut pieces of linen and boil them in a covered utensil prior to using them for wound dressings ( they did not have a pressure cooker ) .
we suggested her to use raw papaya paste for wound debridement till healthy slough was visible .
raw papaya has papain that has exfoliating properties , and can remove dead cells effectively .
this advice was given as we did not have access to facilities for surgical debridement at that point of time .
she was advised to use preboiled and cooled water ( 1 l ) to which one pinch of salt was to be added , thus preparing normal saline .
she was also advised to use turmeric paste to dress the wounds after applying it on a clean piece of linen .
recommended cleaning solutions are sterile water or normal saline ( level - iii evidence ) as disinfectants are toxic to tissues and can impair healing ( level - ii evidence ) .
we taught his wife the importance of frequent change of posture , preferably 2 hourly , to reduce interface pressure .
they could not afford mattresses and hence stress was given on frequent change of posture .
in addition , advice was given to avoid shear and friction forces as far as practicable while changing sheets or clothes of the patient .
we also taught them to pad bony prominences such as sacrum , elbows , greater trochanter , heels , which were particularly prone to pressure sore .
we also taught them about the importance of preventing secondary infection as that would prevent healing , aggravate the wound and could lead to septicaemia and death .
we also highlighted the importance of nutrition and supplementation with vitamins and minerals in prevention and healing of the sores .
we stressed on intake of zinc - enriched food such as peanuts , pumpkin , and watermelon seeds , etc . because of their positive effects on wound healing ( www.healthaliciousness.com/articles/zinc.php ) .
ps could swallow but was anorexic , probably resulting from his constipation , which was compounded by his immobility .
we advised that he should take plenty of water and fluids along with isabol husk that was available locally .
we understand that a stimulant laxative like bisacodyl would have been appropriate combined with a stool softener . however , we only had access to isabol at that point of time and we suggested its use with adequate potassium supplementation .
we also suggested that he should consume bananas and coconut water ( which is rich in potassium and good for gut motility ) , both of which were available in plenty locally .
ps also had significant pain and of a burning nature in his lower back and appeared distressed .
we used the s - lanss ( self - report version of leeds assessment of neuropathic symptoms and signs ) questionnaire in the interview format , which revealed that he had neuropathic pain as well .
he also had difficulty in sleeping at night and was saddened that his wife no longer slept with him .
we gently brought up the issue with his wife and suggested that they talk about it .
we did not consider it appropriate to dive into the issue in detail in our first visit and also to respect the social and cultural issues .
( 500 mg ) , metronidazole ( 400 mg ) , ciprofloxacin ( 500 mg ) , and amitrytiline tablets ( 25 mg ) , which we gave him with instructions for .
his wife was advised to give him a daily bath before wound dressing , followed by topical application of lignocaine gel on the sore and one tablet of paracetamol 20 min prior to change of dressings .
in addition , amitryptiline 25 mg and paracetamol 500 mg were to be given at bedtime .
if we had been afforded the luxury , we would have started him on extended release tramadol ( 100 mg ) given at bed time , thereby ensuring good and pain - free sleep and reviewing his status after a couple of days to guide further therapy .
amitriptyline would act by its sedative , antidepressant and analgesic properties ( for neuropathic pain ) .
amitriptyline acts primarily by inhibiting the reuptake of noradrenaline and serotonin in the descending inhibitory pathways in the spinal cord , thus potentiating analgesia .
we advised that metronidazole tablets be crushed and applied topically on the ulcer to reduce malodour as we suspected anaerobic infection .
the nice guideline clearly states that while implementing evidence - based guidance it is important that all health care professionals understand the local context in which they work our management in this case might seem outrageous but on careful thought , one would realize that we used locally available , affordable , acceptable , and situationally appropriate management strategies .
hydrocolloid or hydrogel - based dressing materials would have been appropriate in this setting in view of the moderate amount of exudation and stage - iii sore . however , we had to use clean linen in view of the non - availability and affordability of proper dressing materials .
a trial found little difference between the use of hydrocolloid dressings and traditional saline - soaked gauze in ulcer healing .
most of the studies comparing different dressing materials did not find any statistically significant benefit over other .
in fact , one study comparing a modern dressing with placebo found no evidence of significant difference in wound closure rates .
ps had many risk factors for development of pressure ulcers such as immobility , poor nutrition , reduced physical activity , poor general physical condition , prolonged pressure , etc .
we assessed his risk index for developing pressure ulcers using waterlow , norton and braden 's scales in conjunction with clinical judgment .
we used a combination of chemical ( papain ) and mechanical methods ( saline irrigation ) for removal of slough and debridement .
there are other nonmechanical debridement agents such as hydrogels , dextranomer polysaccharide beads , adhesive zinc oxide tape , etc .
also , there is no evidence to indicate if surgery is effective in the treatment of pressure ulcers ; however , it is clearly indicated as a treatment option .
we also advised his wife and the local community members to reposition and turn ps within intervals of 2 h if possible based on ps needs and preferences and also on the importance of giving pain relief medications 20 - 30 min prior to this .
ps was also interested in music and we encouraged the community to arrange for a radio so that he could listen to music and the news , thus highlighting the importance of a holistic model of care .
we discussed the burden of the care process with him and his wife and empathized with them .
we even talked to the panchayat ( leader ) of the village to arrange some employment for his wife .
we were able to demonstrate the three central virtues in the praxis of palliative care , namely medical expertise , compassion , and respect for dignity .
we demonstrated our moral values by an unconditional respect for the dignity of ps and the acceptance of human finitude .
our reflections centered upon individual decision making ( micro - ethics ) as well as keeping the socioeconomic and cultural considerations in mind ( macro - ethics ) .
the principle of therapeutic proportionality was well demonstrated in which our moral obligation to provide ups with treatments that fulfilled a relation of due proportion between the employed means and the end pursued was employed .
we demonstrated the ethical principles of beneficence by our intention to provide symptom relief ( physical , psychological , social , and spiritual ) with appropriate use of available , acceptable , and affordable materials and techniques to promote healing of the ulcer .
non - maleficence was demonstrated as we used techniques and clinical practices that were supported by evidence - based medicine .
the principle of autonomy was adhered to by taking ups permission and co - operation in the care process that was discussed with him .
distributive justice was demonstrated as we used techniques and suggestions that were locally available , acceptable , affordable , and appropriate for his social environment .
a review 3 weeks later revealed a happy and confident ps who has minimal pain and good evidence of healing ( wound size - 1.5 cm 2 cm ) .
one group also reported on the topical application of insulin and its significant benefit on wound healing .
also there is insufficient evidence to indicate whether antimicrobials are effective in the management of pressure ulcers .
frequent change in posture to relieve pressure of paramount importanceremove necrotic tissuecontrol / treat infectionprotect new / healthy tissueteam workimprove quality of life holistic approach
frequent change in posture to relieve pressure of paramount importance remove necrotic tissue control / treat infection protect new / healthy tissue improve quality of life holistic approach
frequent change in posture to relieve pressure of paramount importanceremove necrotic tissuecontrol / treat infectionprotect new / healthy tissueteam workimprove quality of life holistic approach
frequent change in posture to relieve pressure of paramount importance remove necrotic tissue control / treat infection protect new / healthy tissue improve quality of life holistic approach
Output:
| managing pressure ulcers remain a challenge and call for a multidisciplinary team approach to care .
even more daunting is the management of such patients in remote locations and in resource constrained situations .
the management of pressure sores in a patient with progressive muscular atrophy has been discussed using resources that were locally available , accessible , and affordable .
community participation was encouraged . a holistic approach to care
was adopted . |
PubmedSumm118742 | ***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: dental trauma is considered a major public oral health problem because the high
prevalence and the impact caused in daily life .
the main causes of traumatic dental injuries are falls and
collisions with people and objects , both factors are very present during sports
practice .
it has been shown that sports practice increases the risk of traumatic injuries such as
dental trauma . in the activities
where contacts with athletes commonly occur , there is more susceptibility to dangerous
falls or blows , and consequently , to dental injuries .
the modalities with increased risk are the contact sports such
as wrestling and collective sports . despite the common belief that soccer is not a violent sport
, it presents a high risk of
injuries to the athletes , including oral and craniofacial injuries .
in fact , during soccer matches the head
is frequently used and the impact
between heads or head and elbow are the most prevalent causes of craniofacial
injuries . in europe , soccer is
responsible for 50% of sports related to orofacial trauma , probably due to the high
popularity of this sport in the continent .
dental trauma , which is a problem that can be prevented , should not affect
the amateur and professional soccer practice .
several authors mentioned that mouthguard
use could prevent the orofacial injuries in different kinds of sports . in spite of this , mouthguard use is not common worldwide .
soccer is the most popular sport in
brazil , with thousand of players in the national , regional or local leagues . in brazil ,
a
literature review performed in indexed basis ( pubmed , lilacs ) showed that no study has
investigated the occurrence and prevention of dental trauma in brazilian professional
soccer . considering that an increased attention has been directed to sports dentistry ,
more investigations regarding dental trauma in sports should be performed .
the aim of this study was to perform a survey regarding the occurrence and prevention of
dental trauma in professional soccer athletes by means of interviews with the medical
departments of professional teams .
the study had the approval of the local ethics committee ( federal university of
pelotas , rs , brazil ) .
each physician in charge for the medical department of the
soccer teams invited to participate in the study received an informational document
about the research and signed an informed consent form prior to enrollment in the
study .
for this study , a closed questionnaire ( tables
1 - 3 ) was prepared and sent to the
head of the medical departments of the 40 teams that were enrolled in the first and
second divisions of brazilian professional league soccer in 2007 . to be included in
the study ,
physicians needed to be working at the medical departments for at least 1
year .
the questionnaire contained questions about the occurrence of traumatic dental
injuries during the matches , the conducts adopted in cases of dental trauma , the
knowledge of mouthguards , and the existence of a dentist as part of the team 's health
professional staff .
absolute and relative frequencies of dental trauma 's occurrence - based questions
in brazilians soccer clubs , 2007 ( ci : confidence interval ) knowledge about mouthguards of health departments ' responsible ( ci : confidence
interval ) the questionnaires with the informational document were posted by regular mail
including envelopes stamped to ensure the return of the answers .
the data obtained was subjected to descriptive
analysis to determine absolute and relative frequencies of answers and 95% confidence
intervals for each one of the questions .
the study had the approval of the local ethics committee ( federal university of
pelotas , rs , brazil ) .
each physician in charge for the medical department of the
soccer teams invited to participate in the study received an informational document
about the research and signed an informed consent form prior to enrollment in the
study .
for this study , a closed questionnaire ( tables
1 - 3 ) was prepared and sent to the
head of the medical departments of the 40 teams that were enrolled in the first and
second divisions of brazilian professional league soccer in 2007 . to be included in
the study ,
physicians needed to be working at the medical departments for at least 1
year .
the questionnaire contained questions about the occurrence of traumatic dental
injuries during the matches , the conducts adopted in cases of dental trauma , the
knowledge of mouthguards , and the existence of a dentist as part of the team 's health
professional staff .
absolute and relative frequencies of dental trauma 's occurrence - based questions
in brazilians soccer clubs , 2007 ( ci : confidence interval ) knowledge about mouthguards of health departments ' responsible ( ci : confidence
interval ) the questionnaires with the informational document were posted by regular mail
including envelopes stamped to ensure the return of the answers .
the data obtained was subjected to descriptive
analysis to determine absolute and relative frequencies of answers and 95% confidence
intervals for each one of the questions .
physicians from 38 ( 95% ) of the 40 teams in the first and second divisions answered the
questionnaires .
table 1 shows the questions about dental trauma
occurrence and the absolute and relative frequencies of the obtained data . regarding the occurrence of dental trauma in professional soccer players , 71.1% of the
physicians saw at least once in their professional experiences , and 29.6% of them saw
more than 4 times .
the most common types of dental injuries observed were dental
fractures ( 74.1% ) followed by avulsions ( 59.3% ) . the players most affected by dental
injuries were forwards ( 59.2% ) and center defenders ( 44.4% ) . when the physicians were questioned about conducts adopted in cases of tooth avulsion
( table 2 ) , 94.6% answered that replantation
of the avulsed tooth is possible , and 76.6% said that it is possible to obtain success
if the replantation is done 6 h or more after the accident .
knowledge of heads of club 's health departments about the conducts to be adopted
in case of dental injuries during the game ( ci : confidence interval ) regarding mouthguard use ( table 3 ) , 48.6% of the
physicians did not know any type of them , and 67.6% had never recommended their use by
the athletes .
the lack of need was the most common reason ( 50% ) for physicians not
recommending mouthguard use .
of the interviewed teams , 52.6% have a dentistry department
included in their medical departments .
injuries are very common in sports , especially in those modalities involving more speed
and close contact between athletes , which are more susceptible to facial and dental
trauma .
although soccer is not
considered a dangerous activity ,
71.1% of the professional soccer team 's physicians that took part in this study reported
having observed dental injuries in soccer players during practice .
this finding is in
accordance with those of several authors that pointed soccer as a violent sport with
high risk of injuries .
however , in this
study , the time of experience of the physicians in the medical departments was not asked
and dental trauma occurrence could be overestimated .
the most frequent kinds of dental
trauma reported in this study were dental fractures ( 74.1% ) and avulsions ( 59.3% ) , which
are considered the most serious types of dental trauma .
such finding could be due to the fact that most severe
injuries are easily perceived , while less severe injuries , like concussions or enamel
fractures , could be underestimated . in the present study , the players more frequently affected by dental trauma
in a recent research , authors watched 10
matches of the premier league ( england ) and closely analyzed 18,000 play actions ,
concluding that when the ball is close to the goal , on defensive or offensive areas , its
possession is most vigorously contested , increasing the injury potential during the
match . despite the fact that the majority of the interviewees answered that they were aware of
the possibility of replanting avulsed teeth , and the need for immediate action for
successful prognosis ,
76.6% of them either reported that an avulsed tooth can be
replanted up to 6 h after the accident or did not know the answer .
the international
association of dental traumatology recommends that replantation must be done at most
after 1 hour of the accident , or the long - term prognosis is not favorable .
the fact that only 52.6% of the teams
have a dentist in their medical department can justify the lack of information about
this subject .
an appropriate treatment plan after injury is important for successful tooth
replantation , and the knowledge
of emergency services plays an important role in this aspect . in this study ,
73.0% of
the physicians interviewed knew a dental emergency service . despite this , a considered
number of brazilian professional soccer teams ( 47.4% ) do not have a dentistry
department , hindering the exchange between health specialties . as a consequence ,
the
majority of the physicians did not have adequate information about the emergency
conducts after a dental avulsion .
this fact becomes more important if we consider that
the physicians are the professionals that assist the athletes in the stadiums during the
matches .
the mandatory wear of mouthguards in various sports like american football , rugby and
boxing , makes it possible the prevention of dental injuries .
however , in
soccer , mouthguard wear is not mandatory ; consequently , the incidence of dental trauma
is higher than other sports considered more violent , like martial arts .
these injuries can be prevented by
protection of buccal region with mouthguards and by other strategies , like application
of preventive programs in players focused in the adherence to the match rules and spirit
of fair play .
studies have
demonstrated that most players do not have sufficient knowledge of prevention of dental
injuries and mouthguards .
forty - eight percent of the physicians in charge for medical departments in soccer teams
in this study had no knowledge of mouthguards , and this could impair the possibilities
of dental trauma prevention .
only 21.6% of the physicians interviewed recommended the regular use of mouthguards for
the players .
this low rate could be attributed to the lack of information regarding to
this protective device .
in fact , the most frequently mentioned reason for not indicating
mouthguards for the players was the belief that they are not necessary ( 50.0% ) .
other
studies have mentioned difficult to communication and breathe , and discomfort as the
main reasons for athletes avoiding mouthguards use .
different types of mouthguards are available and provide a sufficient level of
protection to soccer players .
custom - made mouthguards are considered as the best option
because they offer better protection with more comfort , without causing difficulties to
breathe or talk during the match .
the majority of health professionals
that knew mouthguards in this study described the custom - made ones ( 68.4% ) .
it is
evident that a low proportion of brazilian professional soccer players are wearing
mouthguards during the matches and training activities .
if this situation is present in
the elite soccer , one can assume that a worse situation could be expected in the other
minor leagues .
mouthguards started being used in
professional boxing in the early 1920 's and become mandatory in american football in
1962 , being currently requested in four sport modalities in usa ( ice hockey , lacrosse ,
field hockey and football ) .
however , the american dental association recommends the use
of mouthguards in 29 sports/ exercise activities .
also , meta - analyses have demonstrated
that the risk of an orofacial sports injury was 1.6 - 1.9 times higher when a mouthguard
was not worn .
to improve the situation observed in this study , the inclusion of a dentist as a member
of medical departments of the brazilian soccer professional teams should be mandatory ,
not only for prevention and treatment of dental injuries , but also for maintenance of
players ' oral health . in this context
, sports dentistry emerges as a specialty to supply these and other future
demands that appear in the universe of the professional elite soccer .
worldwide , sports
dentistry has gained an increased interest and brazilian dental professionals should be
aware of this new area of clinical practice . also , the federations or confederations
responsible for sports practice regulation must understand that dentistry is an
important part in the context of systemic health and different dental problems can
impair the performance of professional players .
it can be concluded that dental injuries are common during brazilian professional soccer
practice and that there is a lack of information in the medical departments related to
the emergency conducts and prevention of dental trauma .
strategies should be developed
to improve the knowledge of teams ' health professionals about the prevention and
management of dental injuries .
other studies should be performed to stimulate the
development of sports dentistry in brazil .
Output:
| objectivesthe aims of this study were to verify the occurrence of dental injuries in
professional brazilian soccer players , the level of knowledge of the teams '
medical departments about mouthguards , and the conducts adopted in cases of dental
trauma during the match .
material and methodsclosed questionnaires were sent to the physicians in charge of the medical
departments of the 40 teams enrolled in the first and second divisions of the
brazilian professional soccer league in 2007 .
the data obtained were subjected to
descriptive analysis to determine absolute and relative frequencies of answers for
each one of the questions .
resultsphysicians from 38 ( 95% ) of the 40 teams in the first and second divisions
answered the questionnaires and 71.1% reported the occurrence of some type of
dental injury during soccer practice , dental fractures ( 74.1% ) and avulsions
( 59.3% ) being the most prevalent ones .
regarding emergency conducts , approximately
50% answered that a successful replantation could be obtained in periods from 6 to
24 h after injury , and 27.8% were not able to answer this question .
regarding
mouthguard use , 48.6% of the physicians did not know about mouthguards , and only
21.6% usually recommended their use by the soccer players . among the physicians
who do not recommend the use of mouthguards , 50% justified that it was not
necessary .
almost 50% of the medical departments do not have a dentist as part of
the health professional staff .
conclusionsit was possible to conclude that dental injuries are common during professional
soccer practice and that there is a lack of information in the medical departments
related to the emergency conducts and prevention of dental trauma . |
PubmedSumm118743 | ***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: salmonella enterica serovar typhimurium is a gram - negative enteric motile bacterium and a member of the enterobacteriaceae family .
s. typhimurium can infect humans and animals , leading to the development of gastroenteritis . after entering intestinal epithelial cells , the bacteria damage the microvilli on the surface of the cells .
the pathogenicity of s. enterica infection depends on its ability to invade tissues and survive in macrophages ( 1 ) .
in addition to phagosomal killing resistance via the production of reactive oxygen species ( 2 ) , the emergence of antibiotic resistance has become a serious problem in salmonellosis control and treatment ( 3 ) .
although new antibiotics and medicinal plants have recently been introduced that are effective against infectious disease ( 4 , 5 ) , vaccination is the best way to combat resistance .
vaccination has economic aspects , in addition to hygiene promotion ( 6 , 7 ) .
several oral vaccines are available that killed cellular parts of the bacterium or contain attenuated bacterium .
some vaccines have been produced that include outer membrane proteins ( purines ) of s. typhimurium .
next - generation vaccines have also been developed that utilize polysaccharides as a subunit vaccine , but these polysaccharides are t - cell independent antigens and do not incite memory responses .
consequently , researchers have focused on bivalent subunit conjugate vaccines , which bind the polysaccharide to a proteinaceous macro - carrier as a carrier element in a hapten - carrier model ( 8 - 11 ) .
diphtheria toxoid ( dt ) is a common carrier with a molecular weight of 70 kda and antigenic properties that are used in subunit vaccines ( 12 ) .
in this study , the immunogenicity of ops ( o side chain isolation ) and a dt - conjugated compound was investigated in a mouse model to determine its efficacy as a vaccine candidate .
this was an experimental study performed in the department of microbiology , zanjan branch , islamic azad university , zanjan , ir iran .
s. typhimurium : lyophilized s. typhimurium sh4809 and s. typhimurium sh2201 were purchased ( biological research center of islamic azad university of zanjan ) and cultured on nutrient agar medium ( conda s.a . ,
s. typhimurium sh4809 was used for lipopolysaccharide ( lps ) preparation , and s. typhimurium sh2201 was used in the oral challenge .
lps extraction : bacterial lps was extracted according to published protocols ( 13 , 14 ) .
lps concentration : the tube was centrifuged at 4 c at 2500 rpm for 20 minutes to deplete protein , rna , and dna , and then the volume of the supernatant was measured .
a mixture of 96% ethanol ( merck co. , germany ) and nacl ( 3:1 ) was added to the supernatant and then placed in a refrigerator for 24 hours until halo formation . the next day , the mixture was centrifuged at 4 c , 2500 rpm for 60 minutes .
the supernatant was then discarded , and the residue containing the lps was stored ( 15 ) .
isolation of ops : the tube containing the lps precipitate was refrigerated , and then 4 ml of distilled water were added , and the tube was shaken . to dissolve the precipitate ,
12 ml of distilled water were added , drop by drop , followed by 200 l of 2% acetic acid ( merck co. , germany ) in distilled water .
it was sealed , placed in a beaker and then autoclaved at 120 c for 15 minutes .
next , the tube was centrifuged at 2500 rpm for 30 minutes at 4 c , followed by the addition of 2 grams of trichloroacetic acid ( merck co. , germany ) .
the tube was then shaken and centrifuged at 2500 rpm for 30 minutes at 4 c again
. finally , the ops - containing supernatant was isolated , and 96% ethanol in a volume of 3:1 was added and refrigerated for 2 hours to allow precipitation ( 15 ) .
gel filtration for purification of the o side chains : the ops - containing supernatants were purified , as described previously ( 16 ) . after gel filtration
was completed , the light absorbance of all the fractions was read at 210 nm ( figure 1 ) .
afterward , the absorption spectrum of each tube was measured at 100 and 300 nm , and the contents of tubes with higher absorption were merged with each other .
ph alignment : the ph of the solution was adjusted to 8.5 by adding hcl or naoh ( merck co. , germany ) and incubated in a refrigerator for 24 hours .
endotoxin level of the d - lps samples : the endotoxicity of the antigens was measured using the lal method , as described previously .
the permissible amount of endotoxin for humans is lower than 5 eu / ml ( 15 ) .
. the admissible amount of protein in lps is 10 mg , according to the who protocol ( 17 , 18 ) .
total carbohydrate assay : this assay was performed using phenol , as described previously ( 19 ) .
nucleic acid assay : uv spectrophotometry at 260 nm was performed to check for contamination by dna ( 17 ) .
detoxification of lps : this was done by the alkaline method , as reported previously ( 20 ) .
conjugation of detoxified ops samples with dt : conjugation was performed via the amidation reaction using cyanogen bromide , sodium bicarbonate , adipic acid dihydrazide , and 1-ethyl-3- ( 3-dimethylaminopropyl ) carbodiimide ( edac ) ( sigma co. , uk ) ( 15 , 17 ) . to purify ops - dt conjugation crossed through a sepharose cl-2b chromatography column using the gel filtration method ( 16 ) .
the light absorption of the fractions was then measured at 210 and 280 nm ( figure 2 ) .
the molecules were conjugated when the peaks of light absorption of the curves overlapped at 210 and 280 nm .
rabbit pyrogenicity test : to analyze the pyrogenicity of the prepared conjugations , rabbits were chosen in three groups , and their body temperatures were checked .
after first temperature recording by putting the thermometer into the rabbit s anal , next measurements were done each 15 minutes over a 1-hour period .
the inoculation was done by injecting through ear marginal vein , and the body temperature was recorded each 15 minutes over a 3-hour period .
body temperature changes lower than 0.5 c for each rabbit was considered as apyrogenic inoculum ( 21 ) .
toxicity test : to determine whether the inoculum was toxic , 10 g ( equals one human dosage ) were injected intraperitoneally into three mice .
the animals were then monitored for 7 days to determine weight reductions and mortality ( 21 ) .
sterility test : in this assay , prepared conjugations were cultured on tioglicolate , nutrient agar , blood agar , mac conkey agar , and saboraud dextrose agar ( conda s.a . ,
the media was maintained at both aerobic and anaerobic conditions , and the results were analyzed after an adequate time ( 22 ) .
vaccination : sixty female balb / c mice were purchased from the research institution of pasteur ( karaj , ir iran ) . before the experiment , the mice were housed in standard stainless cages at 23 - 25 c , 60 - 70% humidity , and a 12-hours light / dark cycle for a week .
the first group was vaccinated with ops , and the second group was vaccinated with ops - dt .
the third and fourth groups were vaccinated with dt and normal saline , respectively , as control groups .
the vaccine was administered intraperitoneally three times ( 0.5 cc each time ) for 2 weeks .
two weeks after each injection , peripheral blood was collected from five mice in each group .
each time , the blood was centrifuged at 3000 rpm for 5 minutes to obtain serum and stored at -20 c. enzyme - linked immunosorbent assay ( elisa ) : an indirect elisa was performed to determine the levels of iga , igm , igg3 , igg2b , igg2a , igg1 , and total igg antibodies in the titers , as published previously ( 15 ) .
challenge infection : to attain a satisfying profile of the ops - dt compound , the challenge strain of s. typhimurium sh2201 was cultured on nutrient agar ( conda s.a . ,
afterward , the colonies were suspended in pbs , and the dosage was determined according to the agar plate count technique .
each group ( ops , ops - dt , and control groups ) was orally administered a 50% lethal dose ( ld50 ) of s. typhimurium 21 days after the vaccination doses . to analyze the results of the oral challenge test , all the mice were examined three times daily after 3 days of the challenge for 3 weeks . to determine the clinical status of the animals ,
the following clinical responses to infection were recorded by direct observation : weight , feeding , activity , vitality , appearance , ataxia , and tremor .
the clinical status was scored , with scores for each factor ranging from 0.0 to 5.0 .
the average score of the three daily measurements was determined as the final daily score .
all the challenge procedures were done according to the principles of laboratory animal care ( 23 ) , and they were approved by the ethical committee of islamic azad university , zanjan ( ec 92 - 308 ) . after running the elisa in triplicate , the average titration of each antibody was calculated .
differences between the sera titrations of the ops and ops - dt groups with those of the control groups were analyzed by spss 18.0 software using a t - test , and p < 0.05 was considered a significant difference .
after running the elisa in triplicate , the average titration of each antibody was calculated .
differences between the sera titrations of the ops and ops - dt groups with those of the control groups were analyzed by spss 18.0 software using a t - test , and p < 0.05 was considered a significant difference .
according to the bradford protein assay method , the protein content was 0.2 mg per 1 kg of dried lps .
as shown in figure 2 , the light absorption of the ops - dt conjugations indicated that the ops polysaccharide antigens were conjugated to dt .
the rabbit pyrogen test and animal survival indicated that the prepared conjugations did not contain any pyrogen substance and were not toxic .
the iga titration analysis after the first injection indicated little variation in the iga levels of the ops and ops - dt groups . however , the iga titer of the ops - dt group was higher than that of the ops group 2 weeks after the second and third injections .
the iga titer in the ops - dt group increased from 20 iu / ml to 29.2 iu / ml after the third injection in comparison to the first .
the iga titer increased significantly 2 weeks after the administration of the vaccine , as compared to that of the control groups ( p < 0.001 ) ( table 1 ) . * and * * denotes a significant difference in comparison to the control groups ( p < 0.001 ) .
the igm titer of the ops - dt group increased from 97 iu / ml to 826 iu / ml after the third injection in comparison to after the first injection . the increase in the igm titer of the ops and ops - dt groups after 2 weeks was significant in comparison to that of the control groups ( p < 0.001 ) ( table 2 ) . * and * * denotes a significant difference in comparison to the control groups ( p < 0.001 ) .
the total igg in the titers of the groups vaccinated with the conjugate vaccine increased from 371 iu / ml after the first injection to 1870 iu / ml after the third injection ( table 3 ) .
the igg subclasses in the titers of the groups vaccinated with the conjugate vaccine are listed in tables 4 - 7 . 4 - 7 .
the titers of total igg and those of all the igg subclasses increased significantly after 2 weeks in the ops and ops - dt groups in comparison to those of the control groups ( p < 0.001 ) . * and * * denotes a significant difference in comparison to the control groups ( p < 0.001 ) * and * * denotes a significant difference in comparison to the control groups ( p < 0.001 ) * and * * denotes a significant difference in comparison to the control groups ( p < 0.001 ) . * and
* * denotes a significant difference in comparison to the control groups ( p < 0.001 ) . * and * * denotes a significant difference in comparison to the control groups ( p < 0.001 ) .
according to the antibody titration results , the oral challenge did not affect the clinical status of the ops - dt group .
this group showed strong protection 21 days after exposure to the challenge strain of s. typhimurium .
in contrast , the ops - only group showed little protection against the oral challenge , and the clinical status of the mice declined 2 weeks after the administration of the challenge .
the two control groups showed no protection against the challenge strain , and their clinical status decreased all during 3 weeks evaluation ( figure 3 ) .
the iga titration analysis after the first injection indicated little variation in the iga levels of the ops and ops - dt groups . however , the iga titer of the ops - dt group was higher than that of the ops group 2 weeks after the second and third injections .
the iga titer in the ops - dt group increased from 20 iu / ml to 29.2 iu / ml after the third injection in comparison to the first .
the iga titer increased significantly 2 weeks after the administration of the vaccine , as compared to that of the control groups ( p < 0.001 ) ( table 1 ) . * and * * denotes a significant difference in comparison to the control groups ( p < 0.001 ) .
the igm titer of the ops - dt group increased from 97 iu / ml to 826 iu / ml after the third injection in comparison to after the first injection .
the increase in the igm titer of the ops and ops - dt groups after 2 weeks was significant in comparison to that of the control groups ( p < 0.001 ) ( table 2 ) . * and * * denotes a significant difference in comparison to the control groups ( p < 0.001 ) .
the total igg in the titers of the groups vaccinated with the conjugate vaccine increased from 371 iu / ml after the first injection to 1870 iu / ml after the third injection ( table 3 ) .
the igg subclasses in the titers of the groups vaccinated with the conjugate vaccine are listed in tables 4 - 7 . 4 - 7 .
the titers of total igg and those of all the igg subclasses increased significantly after 2 weeks in the ops and ops - dt groups in comparison to those of the control groups ( p < 0.001 ) . * and
* * denotes a significant difference in comparison to the control groups ( p < 0.001 ) * and * * denotes a significant difference in comparison to the control groups ( p < 0.001 ) * and * * denotes a significant difference in comparison to the control groups ( p < 0.001 ) . * and * * denotes a significant difference in comparison to the control groups ( p < 0.001 ) . * and * * denotes a significant difference in comparison to the control groups ( p < 0.001 ) .
the iga titration analysis after the first injection indicated little variation in the iga levels of the ops and ops - dt groups . however , the iga titer of the ops - dt group was higher than that of the ops group 2 weeks after the second and third injections .
the iga titer in the ops - dt group increased from 20 iu / ml to 29.2 iu / ml after the third injection in comparison to the first .
the iga titer increased significantly 2 weeks after the administration of the vaccine , as compared to that of the control groups ( p < 0.001 ) ( table 1 ) . * and * * denotes a significant difference in comparison to the control groups ( p < 0.001 ) .
the igm titer of the ops - dt group increased from 97 iu / ml to 826 iu / ml after the third injection in comparison to after the first injection .
the increase in the igm titer of the ops and ops - dt groups after 2 weeks was significant in comparison to that of the control groups ( p < 0.001 ) ( table 2 ) . * and * * denotes a significant difference in comparison to the control groups ( p < 0.001 ) .
the total igg in the titers of the groups vaccinated with the conjugate vaccine increased from 371 iu / ml after the first injection to 1870 iu / ml after the third injection ( table 3 ) .
the igg subclasses in the titers of the groups vaccinated with the conjugate vaccine are listed in tables 4 - 7 . 4 - 7 .
the titers of total igg and those of all the igg subclasses increased significantly after 2 weeks in the ops and ops - dt groups in comparison to those of the control groups ( p < 0.001 ) . * and * * denotes a significant difference in comparison to the control groups ( p < 0.001 ) * and * * denotes a significant difference in comparison to the control groups ( p < 0.001 ) * and * * denotes a significant difference in comparison to the control groups ( p < 0.001 ) . * and * * denotes a significant difference in comparison to the control groups ( p < 0.001 ) . * and * * denotes a significant difference in comparison to the control groups ( p < 0.001 ) .
according to the antibody titration results , the oral challenge did not affect the clinical status of the ops - dt group .
this group showed strong protection 21 days after exposure to the challenge strain of s. typhimurium .
in contrast , the ops - only group showed little protection against the oral challenge , and the clinical status of the mice declined 2 weeks after the administration of the challenge .
the two control groups showed no protection against the challenge strain , and their clinical status decreased all during 3 weeks evaluation ( figure 3 ) .
diseases caused by s. typhimurium range from gastroenteritis to systemic infections . at present , no vaccine is available that can induce protective immunity ( 24 ) . in the present study ,
the immunogenicity of the s. typhimurium - derived ops conjugated with dt ( as the carrier protein ) was evaluated to determine its efficacy as a vaccine candidate . in various studies ,
therefore , in the present study , ops , a component of the cell wall component , was used .
many previous studies have tested the potential of bacterial lps as a vaccine candidate antigen .
these studies reported inadequate responses to nontyphoidal s. enterica infections because s. enterica is a facultative intracellular pathogen , and both b- and t - cell responses are required for successful clearance ( 24 ) .
polysaccharides , such as lps , are thymus - independent antigens and can not trigger t cells ; consequently , they can not elicit an efficient memory response .
furthermore , some bacterial polysaccharides are similar to the host s glycolipids and glycoproteins and therefore have poor immunogenicity ( 27 , 28 ) . in addition , as lps is a toxic component , it is not a suitable candidate for use in a vaccine . to eliminate this problem , the toxic portion ( lipid a ) of lps
is removed , and the remaining polysaccharide is used in the vaccine . however , the remaining polysaccharide side chain has low immunogenicity and is thus unable to generate a vigorous immune response , as mentioned above . to increase the immunogenicity of polysaccharides ,
they are bound to an immunogenic protein , resulting in the conversion of a thymus - independent antigen to a thymus - dependent antigen ( 28 ) . in the present study ,
the vaccine candidate was conjugated by dt as a carrier component . in previous studies ,
the results of the present study indicated that the antibody response to ops - dt was comparable to that reported in those studies .
in other research , an acceptable lps - dt conjugate vaccine against pseudomonas aeruginosa was introduced ( 15 ) .
in addition , in the present study , the antibody responses to the ops - dt compound were greater than those to ops .
long - term and effective immunity are crucial requirements of any vaccine ( 32 ) . in the present study ,
increases in the titers of all the antibodies were noticeable after ops - dt vaccination .
the predominant antibody was igg1 , which was similar to that reported in an earlier study ( 15 ) .
it seems that igg1 has the most protective activity . according to a previous study , mucosal and serum antibodies ( iga and igg ) , as well as cell - mediated immunity , provided protection against salmonella infections .
enhanced levels of secretory iga antibodies and serum igg and igm antibodies were also reported to be essential to the efficacy of a vaccine candidate ( 33 ) . in the present study , according to the antibody titers and the results of the oral challenge , ops - dt seemed to provide adequate protection . in this basic research study ,
the ops - dt compound induced a favorable response to s. typhimurium infection in mice .
these results may be helpful in the design of future vaccine and immunization studies against other bacterial infections . in conclusion ,
the antibody response of the ops - dt group was higher than that of the ops group .
the levels of all types of antibodies increased after vaccination , and the predominant antibody was igg1 .
therefore , ops - dt elicited a t - dependent antibody response , which enables isotype switching .
Output:
| backgroundsalmonella enterica serovar typhimurium ( s. typhimurium ) causes gastroenteritis in humans and paratyphoid disease in some animals .
given the emergence of antibiotic resistance , vaccines are more effective than chemotherapy in disease control.objectivesthe aim of this experimental study was to evaluate the immunogenicity of diphtheria toxoid ( dt ) conjugated with s. typhimurium -derived ops ( o side chain isolation ) in mice to determine its potential as a vaccine candidate against salmonellosis.materials and methodslipopolysaccharide ( lps ) was extracted from the bacterial strain .
after isolation of the o side chain of lps , detoxification , and conjugation of the detoxified ops samples with dt , pyrogenicity , toxicity , and sterility tests were performed . to vaccination , four groups of female balb / c mice were used in an immunization test .
antibody responses were measured by the elisa method .
challenging processes were performed to analyze the efficacy of the ops - dt compound.resultstwo weeks after the first vaccination dose , there was no significant difference in the antibody titers of the ops and ops - dt groups . however , after the second and third doses , the antibody titers of the ops - dt group increased significantly compared with those of the control groups ( p < 0.001 ) .
the induction of anti - ops antibodies was as follows : ops - dt > ops . the most anti - ops igg antibody was igg1 .
challenging procedure showed successful protective characteristics in clinical examinations.conclusionsthe results indicated that dt increased anti - ops antibodies against the ops - dt compound .
the antibody response to ops - dt was greater than that to ops alone .
we conclude that ops - dt is an appropriate and acceptable vaccine candidate against salmonellosis . |
PubmedSumm118744 | ***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: congenital leukemia , defined as a leukemia that occurs within 4 to 6 weeks of birth , is rare . excluding down syndrome - related transient neonatal myeloproliferation , its incidence is less than 1% of all childhood leukemia ( 1 , 2 ) .
the diagnostic criteria include the presence of immature leukemic blasts in the blood and in extrahematopoietic tissues and the absence of congenital infections ( syphilis , toxoplasmosis , herpes simplex , cytomegalovirus , rubella , and bacterial infections ) , hypoxia , and hemolytic disease , which may produce a similar clinical and hematological picture .
in addition , there may be absence of chromosomal disorders that may be associated with unstable hematopoiesis , such as trisomy 21 ( 3 ) .
although its biology and natural history are still under investigation , it is clear that the leukemic process originated in utero even in infants diagnosed within the first few months of life ( 2 ) . in infants with congenital leukemia under the age of 1 month ,
it has a higher mortality rate than any other congenital cancer , but recently some reports showed spontaneous remissions ( 3 , 5 ) .
these findings implicate therapeutic dilemmas on deciding which patients to treat or to wait . here
we present a case of congenital myeloid leukemia ( m5 ) initially characterized by the presence of leukemia cutis and hyperleukocytosis with chromosomal abnormality ( double translocation of t[8;16][p11;p13.2 ] and t[17;19][?;q13.3 ] ) . with the fear of toxic effect of chemotherapeutic agents
a term male infant weighing 3,360 gram was born to a 32-yr - old woman after uncomplicated pregnancy .
there was no history of exposure to radiation , any known teratogens , smoking , drinking , or drug use from his mother .
gross examination of the infant noted at birth to have an unusual purpuric rash on his whole body looking like " blueberry - muffin " rash ( fig .
skin examination revealed widespread , scattered , yellowish - colored firm nodules with multiple purpuric macules and papules predominantly on the face and proximal extremities with a few present on the trunk .
a punch - biopsy of a nodule showed proliferation of atypical hematologic cells in the dermis .
blood count at birth revealed white blood cell count of 17310/l with 58.8% neutrophils , 5.3% lymphocytes , 26.1% monocytes , and 0.5% eosinophils ; hemoglobin of 13.9 g / dl ; platelets of 13310/l .
torch titers ( against toxoplasmosis , cytomegalovirus , herpes simplex virus , rubella , and syphilis ) were all negative and blood cultures were also negative .
immunophenotyping showed that blasts were positive for cd14 , cd33 and hla - dr(+ ) .
flow cytometry on the bone marrow showed the blasts to be acute myeloid leukemia ( m5 ) in the french - american - british classification based on the morphologic features and special stains .
the results of special stain were peroxidase ( + ) , pas ( - ) , anae with naf inhibition ( + ) .
cytogenetic analysis revealed 46 , xy karyotype with multiple chromosomal defect , t(8;16)(p11;p13.2 ) , t(17;19)(?;q13.3 ) .
serial white blood cell count showed a progressive rise up to 25610/l with thrombocytopenia of 8810/l .
leukemia cutis also progressed and it became more pronounced on the face and somewhat hardened .
initial chemotherapy was started with daunorubicin , etoposide , and cytarabine , but , he died at 27 days of age .
leukemia is the most common malignancy presented during the childhood , however , congenital leukemia is a very rare disease , representing less than 1% of all childhood leukemia .
it should be differentiated from transient leukemoid reaction and other small round cell tumors ( 3 ) .
maternal alcohol consumption , tobacco smoking , maternal exposures to radiation , high birth weight , high levels of insulin - like growth factors , maternal consumption of topoisomerase ii inhibitors , such as fruits and vegetables , coffee , tea , cocoa , wine , and soybeans are those factors ( 2 , 6 ) . however , as in our case , some had been reported to have no known risk factors . frequently , reported cases of congenital leukemia with constitutional chromosomal abnormalities have led to suspicion whether congenital leukemia is a result of chromosomal fragility ( 2 ) .
congenital leukemia may reflect the early onset of intrauterine leukemia , that is , leukemic process originated in utero even in infants diagnosed within the first few months of life . since embryonic
hematopoiesis begins in undifferentiated mesenchyme starting the third week after fertilization , leukemia cutis may be a primary event and the first manifestation of congenital leukemia ( 6 ) .
prognosis of congenital leukemia is dismal and has a progressive downhill course , even with chemotherapy .
however , there are some reported cases of spontaneous remission ( table 1 ) ( 3 , 7 - 19 ) .
the reason that spontaneous remissions may occur in newborn infants is unclear ( 1 ) . the period of spontaneous remission varied widely from months to years , and several of the children with relapses remained in prolonged remission after chemotherapy ( 3 , 15 ) .
there appear to be no common clinical features between those who progressed and those that had spontaneous remissions .
neither bone marrow involvement at diagnosis nor hyperleukocytosis appears to increase the risk of relapse ( 3 , 4 , 15 - 17 , 19 ) .
chromosome abnormalities affecting chromosome 11 band q23 are involved in the majority of infant leukemia cases .
the major translocations involving the 11q23 locus are t(4;11 ) and t(11;19 ) ( 13 , 16 ) .
translocation involving 11q23 band or reciprocal translocations involving chromosomes 8 and 16 are known to be mapped with oncogene(s ) and are known to be associated with a poor prognosis ( 6 , 10 , 30 ) .
hence , even cytogenetic abnormality of 11q23 rearrangement of skin without involvement of bone morrow was also treated aggressively ( 6 ) .
moreover , aml with the t(8;16 ) is associated with a young age at diagnosis , myelomonocytic ( fab m4 ) or monocytic ( fab m5 ) morphology , erythrophagocytosis , disseminated intravascular coagulation and a poor outcome ( 9 ) .
the gene at 11q23 , known as mll ( all-1 , hrx , htrx , or hu - ets-1 ) , is required for the production of normal numbers of hematopoietic precursors and for their proper differentiation ( 2 , 13 ) .
translocations involving mll may fuse with other genes and hence mll usually retains at least two dna binding domains ( 2 , 13 ) .
since there are a few reports of double translocations as our case , exact meaning of double gene translocation is yet to be discussed .
because of the rarity of this disease , there is no standard protocol of chemotherapy .
although there had been reported cases of prolonged periods of remission , rapidly downhill course were also noted in some cases and some of them died after relapse during the course of chemotherapy ( 16 - 18 ) . while some cases with t(8 ; 16 ) remitted spontaneously without treatment ( 3 , 9 , 10 ) , paradoxically , those who had chromosomal abnormalities died after initiation of chemotherapy as our case ( 4 , 6 , 20 , 23 , 26 - 29 ) .
it seems like that karyotypic findings in blasts in the neonatal period may not be predictive of whether or not a spontaneous remission will occur ( 2 ) . for our case ,
hyperleukocytosis , progressive leukemia cutis , bone marrow involvement , double translocation involving ( 8;16 ) made us to decide to treat at first .
however , with the fear of unknown toxic effect of chemotherapeutic agents , parents refused to treat .
three weeks later after parents ' agreement , we treated with daunorubicin , etoposide , and cytarabine but he died of pulmonary hemorrhage three days after induction chemotherapy .
he may died of leukemia itself but , we are not sure whether he died due to chemotherapy or he could have survived with only conservative management as other spontaneous remitted cases . that is because it is the first case of congenital aml with double translocation of ( 8;16 ) and ( 17;19 ) to be reported in the english literature to the best of our knowledge .
although congenital leukemia remains a rare disorder , an international collection of data or register system is indispensable for establishing an optimal treatment protocols .
Output:
| congenital leukemia is uncommon and excluding transient myeloproliferation associated with down syndrome , makes up approximately 1% of childhood leukemias .
a newborn boy was born with multiple subcutaneous nodules and large purpuric papules .
skin biopsy revealed proliferation of atypical hematologic cells in the dermis .
bone marrow morphology was consistent with acute myeloid leukemia ( m5 ) and cytogenetic studies revealed t(8;16 ) and t(17;19 ) double translocation .
although prognosis of congenital leukemia is known to be dismal , recent reports showed spontaneous remissions . with the fear of chemotherapy - related toxicity , to treat or not to treat
may be a dilemma both to parents and pediatricians .
we report our experience and review the literature . |
PubmedSumm118745 | ***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: four years after food and drug administration ( fda ) approval , the first oral treatment for relapsing forms of ms , fty720 , is showing good efficacy for managing morbidity and the progression of active disease . therapeutically , the benefit afforded by fty720 in managing symptoms of relapsing - remitting ms appears largely dependent on s1p1-dependent modulation on immune blood cells , neurons , astrocytes and endothelia , all mediated by its active phosphorylated fty720-p ( s1p - mimic , figure 1 ) product . in 1996 , closely following its synthesis , fty720 demonstrated efficacy in preventing transplant rejection across animal models due to its potent immunosuppressive action .
it later became discontinued for that indication based on findings that fty720 did not afford additional benefit to standard of care therapy .
findings that s1p1 modulation was the driving force behind fty720 's efficacy and that the fty720-mediated sequestration of circulating lymphocytes , or immune modulation ( correlated with positive therapeutic outcomes ) , has prompted the search for second - generation compounds .
these compounds either have a structural similarity to the fty720 prodrug backbone , or are newer , directly acting modulators having chemically optimized aromatic backbones and a higher selectivity window for s1p1 over s1p3 , while still having s1p5 activity ( figure 2 and table 1 ) . the other difference between the newer class modulators and fty720 appears to be in the time course of immunosuppression , with the newer compounds having shorter half - lives and a shorter duration of lymphopenia , in contrast to the long - lasting fty720 actions .
in addition , the therapeutic efficacy of the newer compounds appears to correlate well with the lymphocyte reduction mechanism(s ) first defined by fty720 . in ms , there are several s1p receptor modulators being tested , such as siponimod , krp-203 , cs-0777 , and rpc-1063 .
siponimod is an oral , second - generation s1p1/5 modulator in phase 3 development for secondary progressive ms .
the results from the bold siponimod study , an adaptive dose - ranging phase 2 study , were published in 2013 and showed that , compared to placebo , siponimod reduced brain magnetic resonance imaging ( mri ) lesions and relapses by up to 80% in relapsing - remitting ms .
phase 3 development of siponimod in secondary progressive ms started in 2012 , and results should be available in 2017 .
this article will highlight key preclinical findings of immunomodulators with a high selectivity window for s1p1 and/or s1p5 in support of furthering available treatment options in various autoimmune conditions .
a ) sphingosine is a substrate for two long - chain base kinases , sphingosine kinase 1 and 2 ( sphk1 and sphk2 ) , which phosphorylate sphingosine on its primary hydroxyl group generating s1p .
s1p accumulation in distinct intracellular environments also mediates a variety of biological processes through non - receptor - mediated mechanisms .
these processes include a role for sphk2-generated s1p in the apoptosis of lymphoid cells and sphk2-mediated s1p formation and s1p binding to the histone deacetylases hdac1 and hdac2 to control gene transcription .
s1p can also be degraded intracellularly by dephosphorylation to sphingosine , or being diverted from lysolipid metabolism by degradation to phosphatidylethanolamine and hexadecanal by s1p lyase .
b ) circulating s1p binds to and activates five high - affinity g protein - coupled receptors ( gpcrs ) , s1p1 - 5 .
unlike sphingosine phosphorylation , fty720 phosphorylation appears to be exclusively mediated by sphk2 whereas the dephosphorylation of fty720-p has been shown to involve both lipid phosphate phosphatase 3 and 1a .
fty720-p is able to bind with high nanomolar affinity to all s1p receptors , except s1p2 .
in addition to s1p receptors , the prodrug has been found to target cytosolic phospholipase a2 ( cpla2 ) , sphingosine lyase , and transient receptor potential cation channel ( trp7 ) and while these other interactions may not prove critical in the regulation of lymphocyte sequestration by fty720 , they may play a role in its tolerability and potential side effects following long - term , broad exposure in patients .
structures of the endogenous ligand s1p , the non - selective s1p1,3 - 5 receptor modulator pro - drugs fty720 and aal - r , the s1p1/4/5 modulator prodrug krp-203 , and the s1p1/5 modulators ceralifimod , ponesimod , siponimod , cym-5442 and rp-001 .
av - block , atrioventricular block ; fev , forced expiratory volume ; ms , multiple sclerosis ; rr - ms , relapsing - remitting ms ; sp - ms , secondary progressive multiple sclerosis ; s1p , sphingosine-1-phosphate ; uc , ulcerative colitis .
first - line corticosteroidal therapy and sulfasalazine ameliorate intestinal inflammation but have substantial toxicity . suppressing local inflammation to the intestine by conventional 5-aminosalicylic acids ( 5-asa ) therapeutics reduces and
second - line anti - tumor necrosis factor alpha ( tnf- ) monoclonal antibodies , though safer than conventional immunosuppressants , are another option , yet can lose effectiveness over time , and can predispose certain patients to potentially fatal opportunistic infections .
s1p receptor modulatory strategies have been evaluated in animal models of ibd in the past .
data using fty720 and krp-203 , and later backed by the ono-4641 prototype w-061 ( s1p1/5 modulator of unpublished structure ) , show effectiveness for alleviating multiple aspects of chronic intestinal inflammation .
krp-203 is a s1p1/4/5 agonist prodrug with a molecular structure resembling fty720 . like fty720 , krp-203 sequesters circulating lymphocytes in secondary lymphoid organs in mice , and was first shown to prolong skin and heart allograft survival and significantly attenuate chronic rejection .
the efficacy of krp-203 was assessed in the validated il-10-deficient mouse model of human ibd .
il-10 knockouts develop distal small bowel inflammation spontaneously and display hallmark ibd histolopathological findings due to immune cell recruitment to the mucosa , enhanced production of t helper ( th)-1 cytokines , resulting in the disruption of the mucosal barrier , low body weight and poor survival .
song et al . reported that krp-203 administration to il-10 knockout mice reduced mortality once the disease had been established . both acute , 7-day , and chronic , 28-day , daily krp-203 protocols reduced histological scores in the colon and prevented weight loss vs. vehicle - treated controls . a decreased recruitment of lymphocytes to the colonic lamina propria in the krp-203 group correlated with the survival benefit and the immunohistological findings .
a separate study using w-061 reported reduced inflammation to the distal colon of mice that underwent chemical dextran sodium sulfate ( dss)-induced colitis .
w-061 administration in this model reduced cellular infiltration to the colonic lamina propria , with associated reductions in th17 and th1 cytokines as measured in cultured cd4-t cells isolated from the w-061 treated group at study end .
w-061 also prevented mucosal thickness and mucin depletion induced by dss , relative to vehicle treatment .
the results with krp-203 and w-061 are promising and recapitulate some of the findings of fty720 in animal models of ibd .
fty720 at low 0.3 mg / kg dose was effective in preventing body weight loss in the dss colitis model and the cd4 + cd62l+ t cell transfer models of colitis .
in addition , therapeutic efficacy of fty720 was reported in the 2,4,6-trinitrobenzenesulfonic acid ( tnbs ) inflammatory colitis model , whereby drug treatment led to the dampening of il-12p70 and subsequent th1 pro - inflammatory cytokines , while simultaneously inducing the functional activity of cd4+cd25 + regulatory t cells .
this indicates that , besides migration and the homing of lymphocytes to secondary lymphoid organs via s1p1 , fty720 can also influence cytokine effector function directly , as was shown by the prophylactic and therapeutic efficacy of fty720 in the th2-mediated oxazolone - induced colitis model in balb / c mice .
another class of s1p1 modulator , rpc-1063 ( of unpublished structure , but of similar backbone to rp-001 , figure 2 ) , is being currently tested worldwide as an oral therapeutic in phase 2 clinical trials of uc . in healthy subjects
, rpc-1063 has shown no qtc interval alterations , and is additionally being evaluated in phase 3 trials in relapsing - remitting ms .
fty720 has been compared against methylprednisolone in the mlr / lpr experimental autoimmune lupus mouse model , which has a mutation in t cell - dependent immune dysfunction with human - like sle phenotype .
the clinical goal of therapy relies on suppressing the renal complications , or lupus nephritis that leads the mortality index in sle .
genetically modified mrl / lpr mice have a mutational deficit in the fas - mediated apoptosis of lymphoid cells , and spontaneously develop severe glomerulonephritis , vasculitis and tubular atrophy , replicating some of the clinical features of the human disease .
proteinuria , microscopic deposition of anti - double stranded dna antibodies with complement contribution are strong markers of kidney malfunction in mlr / lpr mice , as well as in patients with sle .
okazaki et al . reported on survival , disease biomarkers , apoptotic indexes , and immune cellularity in mrl / lpr mice treated with fty720 or methylprednisolone . fty720 and the steroid showed survival protection vs. controls , with reduced igg glomerular complex deposition consistent with the survival advantage .
notably , fty720 treated mlr / lpr mice had drug - induced apoptotic destruction of a double - negative t cell population that is inherently dysregulated in this model . while the paper did not report on histopathology , wenderfer et al
. showed histological findings after a 12-week 6 mg / kg krp-203 daily dosing study in mlr / lpr mice .
drug treatment increased survival only at therapeutic dosing , inhibiting glomerulonephritis , vasculitis and tubular atrophy .
there was also decreased proteinuria by krp-203 , although no differences in serum anti - double stranded dna iggs titers were noted .
findings that krp-203 , like fty720 , promoted dose - dependent apoptosis in double - negative t cells in mlr / lpr mice strongly support the argument that s1p receptor targeting efficacy , in this model , is mostly dependent on fas - independent pathway apoptosis .
the selective s1p1/3/5 modulator ponesimod has successfully met the primary endpoint of efficacy and safety in patients with moderate to severe chronic plaque psoriasis .
the proportion of patients with at least 75% improvement in psoriasis area and severity index ( pasi ) from baseline ( pasi75 ) at week 16 was determined in a double - blind , placebo - controlled study consisting of 326 patients . with ponesimod 20 mg daily , nearly half of patients improved by at least 75% at week 16 ( p < 0.0001 vs. placebo ) .
doubling the dose improved the outcome by at least 75% in patients at week 16 ( p < 0.0001 vs. placebo ) , whereas only 13.4% of the placebo group improved by 75% .
safety and tolerability data from this study were consistent with the safety profile of ponesimod observed in the past , including a phase 2 study in ms . as expected of s1p receptor modulators , there was a transient bradycardia and , less frequently , a transient effect on atrioventricular conduction . dyspnea and
these results suggest that ponesimod could become a first in its class , oral therapeutic for treating psoriasis , although it has been discontinued as a potential ms therapeutic .
early studies of acute viral lung pathogenesis , using the wsn strain of the influenza a virus , demonstrated that compounds targeting multiple s1p receptor subtypes suppressed the cytokine response during infection .
specifically , the results demonstrated that intratracheal but not intraperitoneal administration of aal - r , an fty720 analog ( table 1 ) , to infected mice reduced mortality and the accumulation and proliferation of activated cd8 + -t cells into the lung .
subsequent studies with cym-5442 and rp-001 , compounds designed to target only the s1p1 subtype , also significantly reduced morbidity and mortality in mice infected with the highly virulent human isolate of pandemic 2009 h1n1 . the authors proposed that these compounds increased survival by blunting and not abolishing excessive cytokine production often associated with certain virus strains .
a follow up animal study using ferrets , a relevant model used in influenza research due to its human - like mode of airway viral propagation and ability to develop symptoms seen in humans , were performed using the s1p1-specific agonist rp-002 .
the study demonstrated that agonism of the s1p1 receptor down - regulated and controlled the overly robust innate inflammatory response while minimally altering viral replication .
gavage administration of rp-002 to h1n1:2009 infected ferrets significantly reduced mortality as compared to vehicle - administered controls .
additionally , the survival benefit in the ferret study was improved upon co - administration of rp-002 with the neuraminidase inhibitor oseltamivir .
the authors concluded that rp-002 and oseltamivir as combined therapy conferred maximal protection by blunting both the immune pathology and viral replication .
the mechanism used by the s1p1 receptor to modulate cytokine secretion and subsequent morbidity remains unknown .
future studies should examine whether the s1p1 receptor directly modulates toll - like receptor-7 ( tlr-7 ) .
it is feasible that both of these transmembrane proteins reside in the same subcellular compartment and upon s1p1 agonism whether a transient disruption of tlr-7 's microdomain occurs .
this disruption may result in the abrogation of tlr-7 signaling through the canonical myd88-irf-7 pathway . since this pathway is chemically tractable
overall , the data is promising in defining a proof - of - concept mechanism and should be carefully explored as an option to dampen excessive host innate immune collateral damage from highly pathogenic viruses .
early studies of acute viral lung pathogenesis , using the wsn strain of the influenza a virus , demonstrated that compounds targeting multiple s1p receptor subtypes suppressed the cytokine response during infection .
specifically , the results demonstrated that intratracheal but not intraperitoneal administration of aal - r , an fty720 analog ( table 1 ) , to infected mice reduced mortality and the accumulation and proliferation of activated cd8 + -t cells into the lung .
subsequent studies with cym-5442 and rp-001 , compounds designed to target only the s1p1 subtype , also significantly reduced morbidity and mortality in mice infected with the highly virulent human isolate of pandemic 2009 h1n1 .
the authors proposed that these compounds increased survival by blunting and not abolishing excessive cytokine production often associated with certain virus strains .
a follow up animal study using ferrets , a relevant model used in influenza research due to its human - like mode of airway viral propagation and ability to develop symptoms seen in humans , were performed using the s1p1-specific agonist rp-002 .
the study demonstrated that agonism of the s1p1 receptor down - regulated and controlled the overly robust innate inflammatory response while minimally altering viral replication .
gavage administration of rp-002 to h1n1:2009 infected ferrets significantly reduced mortality as compared to vehicle - administered controls .
additionally , the survival benefit in the ferret study was improved upon co - administration of rp-002 with the neuraminidase inhibitor oseltamivir .
the authors concluded that rp-002 and oseltamivir as combined therapy conferred maximal protection by blunting both the immune pathology and viral replication .
the mechanism used by the s1p1 receptor to modulate cytokine secretion and subsequent morbidity remains unknown .
future studies should examine whether the s1p1 receptor directly modulates toll - like receptor-7 ( tlr-7 ) .
it is feasible that both of these transmembrane proteins reside in the same subcellular compartment and upon s1p1 agonism whether a transient disruption of tlr-7 's microdomain occurs .
this disruption may result in the abrogation of tlr-7 signaling through the canonical myd88-irf-7 pathway . since this pathway is chemically tractable
overall , the data is promising in defining a proof - of - concept mechanism and should be carefully explored as an option to dampen excessive host innate immune collateral damage from highly pathogenic viruses .
the remarkable impact of therapeutic modulation of the s1p - s1pr1 axis reflects the multi - point interdiction of autoimmune pathogenesis . by blunting but not abolishing immune protection
, these therapies provide unprecedented efficacy in ms and uc with a tolerability window that enhances the possibilities of treating autoimmune diseases with fewer infectious complications . because disease relapse is clinically unpredictable , and especially difficult to treat in certain patients , evaluation of s1p receptor modulatory therapies needs to be thoroughly explored in additional pre - clinical studies .
underlying the disease is a chronic and progressive state of local inflammation known to alter the metabolism of pathway(s ) regulating s1p levels .
for instance , intestinal biopsy samples in patients with uc reveal a deregulated metabolic pathway whereby sphingosine kinase 1 ( sphk-1 ) and s1p phosphohydrolase-1 ( sph - ppase ) are upregulated and sphingosine 1-phosphate lyase ( spl ) is downregulated ( figure 1 ) , leading to high local tissue s1p concentration .
sphk-1 upregulation in humans is consistent with a key role of sphk1 in promoting murine intestinal inflammation and colitis - associated cancer via hyperactive intestinal nuclear factor-b ( nf - kb)-signal transducer and activator of transcription 3 ( stat-3 ) signaling .
one important question is whether s1p1 modulation alone would be sufficient to clinically reduce fully active intestinal disease , or whether it may be indicated as maintenance therapy .
the other question is whether global immunomodulation by s1p1 selective or s1p1/5 selective compounds may be contraindicated with adjunct therapeutics of ibd , as shown with tnf- blockers and other immunomodulators .
the uc touchstone phase 2 clinical trial results demonstrated the medically significant efficacy of daily 1 mg rpc1063 .
the study enrolled 199 patients split into three arms , placebo , low dose ( 0.5 mg ) and high dose ( 1.0 mg ) . at 8 weeks of treatment , induction of clinical remission reported by standard mayo scoring , was 16.4% ( p
< 0.05 ) of the patients on the 1 mg dose as compared to 6.4% on placebo .
whether human genetic factors are involved that would alter the predisposition for such sphk-1 pathways in uc and colitis - associated cancer needs to be investigated , and whether s1p1 and or s1p1/5 modulator therapy can dampen inflammation - promoting colitis - associated cancer is not known .
nevertheless , s1p1 modulations of lymphocyte trafficking and cytokine production strategies represent a good opportunity to reduce intestinal inflammation in ibd and provide a steroid alternative to chronic use .
hugh rosen is a scientific co - founder and scientific advisory board member of receptos and has a significant financial interest in the company .
Output:
| development of sphingosine-1-phosphate receptor 1 ( s1p1 ) modulators to dampen inflammation and its sequelae is becoming increasingly promising for treating medical conditions characterized by significant immunopathology . as shown by the non - selective s1p receptor modulator fty720 ( fingolimod [ gilenya ] ) in the treatment of relapsing - remitting multiple sclerosis ( ms ) , the ability to use s1p1 modulation to precisely block immune cell traffic
immunomodulation while maintaining immunosurveillance , has opened therapeutic opportunities in various other immune - derived chronic pathologies , including inflammatory bowel disease ( ibd ) , lupus , psoriasis , as well as , potentially , in early acute viral respiratory infection .
proof - of - concept studies across validated animal models with s1p receptor modulators highly selective for s1p1 , such as baf-312 ( siponimod ) , krp-203 , ono-4641 ( ceralifimod ) , ponesimod and rpc-1063 , and emerging clinical trials for safety and efficacy in humans , particularly in ms , ulcerative colitis ( uc ) and psoriasis , have set the stage for us to consider additional testing in various other autoimmune diseases . |
PubmedSumm118746 | ***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: vitamin d is considered a collection of fat - soluble steroids that found in two forms : vitamin d3 ( cholecalciferol ) from animal sources and vitamin d2 ( ergocalciferol ) from plant sources .
although vitamin d can be obtained from few dietary sources including oily fish ( salmon ) , eggs , fortified dairy products , or pharmacologic supplementation , most vitamin d requirements are provided from natural synthesis in the skin .
the 7-dehydrocholesterol in plasma membranes of the epidermis and dermis through sunlight exposure , ultraviolet b rays can be converted to vitamin d3 .
vitamin d from the skin and diet is activated during 25-hydroxylation in the liver , 25-hydroxyvitamin d ( 25(oh)d ) , and subsequent hydroxylation in the kidneys , 1,25-dihydroxyvitamin d ( 1,25(oh ) 2d ) .
25(oh)d , calcidiol , is the dominant metabolite of vitamin d in the circulation that represented the vitamin d status and 1,25(oh ) 2d , calcitriol , is known as the biological active form of vitamin d. the hormonal activity of calcitriol is exerted through binding to the nuclear vitamin d receptor ( vdr ) .
normal serum 25(oh)d value is 20 ng / ml ( 50 nmol / l ) which if be < 20 ng / ml is classified into the deficiency category .
low sun exposure , reduced dietary vitamin d intake , and older age are the most common factors associated with vitamin d deficiency .
the rate of inadequate vitamin d levels among younger and older postmenopausal women has been estimated to be about 50% globally . the suboptimal levels of 25(oh)d below 30 ng / ml was also reported in more than 50% of postmenopausal women consuming osteoporosis medication .
prevalence of vitamin d insufficiency and marginal status is higher in female than male population .
as vitamin d has important physiological functions through maintaining mineral homeostasis , it has proposed that vitamin d deficiency can lead to several musculoskeletal disorders including rickets and skeletal abnormalities in children , osteomalacia , osteopenia , osteoporosis , and incidence of fractures in adults . in recent years , researchers found that vdrs were expressed in several tissues and cells and , therefore , had a wide range of biological functions .
therefore , many hypotheses arose that low vitamin d values may be associated with various diseases such as cancers , infections , autoimmune diseases , diabetes mellitus , and cardiovascular diseases .
recent attention has been focused on the vitamin d effects on body health and the association between vitamin d and diseases has been extensively investigated in several studies . in this article , we assessed the recent review studies in regarding the roles of vitamin d in the several aspects of women health .
a literature search was conducted to identify studies assessing the associations of vitamin d intake and/or serum 25(oh)d levels with the risk of incident breast cancer , ovarian or endometrial cancers , hypertension , and osteoporosis .
search keywords included vitamin d , 25(oh)d , 1 , 25-dihydroxyvitamin d , breast cancer , ovarian cancer , endometrial cancer , hypertension , and osteoporosis .
then , the full text of remained papers was reviewed for those articles with relevant relationships .
finally , the most current systematic reviews and meta - analyses in this regards were selected .
flowchart of conducted studies in the field of vitamin d studies examined association of vitamin d and some of the health outcomes breast cancer is considered a common disease and a leading cause of mortality in women .
it has been estimated that there are approximately 1.4 million new cases of breast cancer and over 450,000 mortality annually .
there are several well - established risk factors for breast cancer such as age , gender , density of breast tissue , parity , genetic , and alcohol use .
vitamin d plays the important roles in the mammary gland through regulation of calcium transport during lactation , differentiation hormones , and milk protein production .
the complex of vitamin d and vdrs in the normal breast epithelial cells can regulate transcription of more than sixty genes that are responsible for effects of antiproliferative , prodifferentiating , antimetastatic , and proapoptotic on cells .
it has been suggested that vitamin d can lead to the decrease in benign epithelial proliferation disorders and subsequently the breast cancer risk through reduction of breast mammographic density and antiproliferation and prodifferentiation activities .
although evidence from experimental and laboratory studies has generally shown an association between higher vitamin d levels and lower breast cancer risk , the results of human researches are somewhat controversial .
reviewed the studies examining the association between breast cancer and vitamin d from different sources ( skin synthesis or food or supplementation ) .
they suggested that elevated serum 25(oh)d levels through the sun exposure as well as dietary intake and an over 400 iu / day vitamin d supplementation were associated with a reduced risk of breast cancer .
similar findings were also reported in a pooled analysis on the 11 epidemiological studies regarding the relationship between levels of serum 25(oh)d and breast cancer risk .
it was observed that individuals in the highest quintile versus the lowest quintile of serum 25(oh)d had a reduction in risk of breast cancer ( odds ratio [ or ] = 0.63 , 95% confidence interval [ ci ] = 0.470.80 ) . on the other hand , this study reported that there was an approximately 10% reduction in risk of breast cancer followed by every 10 ng / ml increase in serum 25(oh)d concentration .
another meta - analysis by maalmi et al . including five prospective cohort studies during a follow - up of 2.724 years has been conducted to evaluate the association between serum 25(oh)d levels and survival among patients with breast cancer .
they observed that patients with high 25(oh)d levels had a significant reduced risk of overall mortality ( hazard ratio [ hr ] = 0.62 , 95% ci = 0.490.78 ) and breast cancer - specific mortality ( hr = 0.57 , 95% ci = 0.380.84 ) compared to patients with low 25(oh)d levels .
furthermore , dose - response analyses demonstrated that the increase in 25(oh)d by 20 nmol / l leads to reduce in overall ( hr = 0.82 , 95% ci = 0.750.88 ) and breast cancer - specific ( hr = 0.82 , 95% ci = 0.710.93 ) mortality .
however , this significant association between vitamin d and risk of breast cancer in pervious reviews has not been completely confirmed by other researches .
a meta - analysis by comparing the high and low total vitamin d intake showed that there is a significant association between vitamin d intake and breast cancer risk in cohort studies ( relative risk [ rr ] = 0.90 , 95% ci = 0.830.98 ) but not in the case control studies ( rr = 0.95 , 95% ci = 0.691.32 ) .
in addition , when subgroup analysis was conducted according to menopausal status , there was a significant association between vitamin d intake and breast cancer risk in the premenopausal women ( rr = 0.83 , 95% ci = 0.730.95 ) .
on the other hand , no significant inverse relationship between circulating 25(oh)d levels and risk of breast cancer was observed in the both postmenopausal and premenopausal women .
furthermore , the findings of dose - response meta - analysis comprising 5206 cases of breast cancer and 6450 controls demonstrated that there was a marginal significant inverse association between circulating 25(oh)d and risk of breast cancer ( rr/5 ng / ml = 0.99 , 95% ci = 0.971.00 ) .
moreover , this meta - analysis revealed that menopause status can be affected on association between plasma 25(oh)d and breast cancer risk .
although the inverse relationship between circulating 25(oh)d and risk of breast cancer was observed in the postmenopausal women ( rr/5 ng / ml = 0.97 , 95% ci = 0.931.00 ) , there was no dose - response association among premenopausal women ( rr/5 ng / ml = 1.01 , 95% ci = 0.981.04 ) .
however , no reduction in risk of postmenopausal breast cancer per 5 ng / ml increase in 25(oh)d was observed above 35 ng / ml of 25(oh)d concentration .
the results of cohorts participating in the chances consortium showed that there was no association between lower 25(oh)d concentrations and increment of most cancers .
however , there was some evidence of increased breast cancer risk with higher 25(oh)d concentrations .
several risk factors have been recognized for these cancers such as old age , family history , high estrogen and low progesterone levels , nulliparity , and obesity .
the vdrs have been detected in endometrial and ovarian cell lines which mediate the role of 1,25(oh)2d in these tissues .
moreover , it has been suggested that 1,25(oh)2d can lead to inhibition of cell proliferation and induction of apoptosis in the ovarian cancer cells through down - regulation of telomerase activity .
although these biological reasons suggest that vitamin d may associate with the incidence and mortality of ovarian and endometrial cancers , the exact role of vitamin d in the etiology of these cancers has remained controversial .
the results of the studies that conducted in this field are not consistent . in a systematic review ,
the evidence related to association between ovarian cancer occurrence or mortality with vitamin d levels was evaluated .
although there was a reductions in the incidence or mortality with increased latitude , sunlight , or dietary / supplement vitamin d intake in the approximately half of the ecologic and case control studies , the other half case control and cohort studies reported no significant associations .
this systematic review suggests that there is no strong evidence regarding whether the increased vitamin d levels can reduce the risk of ovarian cancer incidence or mortality . in a nested case control study , including 830 endometrial cancer cases from seven cohorts , no associations were observed between 25(oh)d concentration and endometrial cancers risk .
the results regarding the association between circulating 25(oh)d and endometrial cancer risk represented that there was a nonsignificant overall ors associated with concentrations of < 25
nmol / l ( 0.98 , 95% ci = 0.711.35 ) to compare with the reference category ( 5075
nmol / l ) . indeed , these findings did not support the protective role of vitamin d against the endometrial cancer . in another meta - analysis including 883 cases of ovarian cancer , the association between 25(oh)d and the ovarian cancer risk was assessed .
although in the seven studies , a tentatively reduced risk of ovarian cancer incidence was observed , there was no significant inverse relationship in pooled analyses ( rr = 0.83 , 95% ci = 0.631.08 , p = 0.166 ) for an increase levels of circulating 25(oh)d by 20 ng / ml .
hypertension is considered a prevalent disorder worldwide as well as among the iranian population which imposes a substantial burden on the health system .
although vitamin d deficiency is another influential factor regarding high blood pressure ( bp ) , the role of serum vitamin d levels on hypertension remained not clear .
negative regulation of the renin gene , direct effects on vascular function through existence of 1-hydroxylase enzyme in the endothelial and vascular smooth muscle cells , and playing an important role in calcium metabolism are several potential mechanisms associating the regulation of vitamin d on bp which are not firmly established .
indeed , it has been assumed that vitamin d deficiency can promote the secondary hyperparathyroidism , increment the aldosterone secretion , and stimulate the renin - angiotensin system .
although a number of observational and epidemiologic researches have proposed that vitamin d deficiency can be associated with hypertension , in some trials , there are no convincing results representing that vitamin d supplementation has a protective role in hypertension .
liu et al . reviewed the evidence associating the effects of vitamin d on bp in postmenopausal women .
they found a direct association between low vitamin d status and hypertension in observational studies .
this review suggested that in hypertensive patients with vitamin d deficiency , vitamin d supplementation can be more effective .
similar findings were also reported in another review evaluating the association between vitamin d and the risk of developing elevated bp .
although there were strong observational evidence representing the association between vitamin d deficiency and hypertension , clinical trials have yielded inconclusive results .
a meta - analysis of 46 trials which comprised 4541 subjects was conducted to assess whether vitamin d supplementation can reduce bp .
the results found no significant effect of vitamin d supplementation on systolic ( effect size = 0.0 , 95% ci = 0.80.8 mmhg ) or diastolic bp ( effect size= 0.1 , 95% ci = 0.60.5 mmhg ) .
another systematic review and meta - analysis studied the evidence of prospective studies that investigated the associations of circulating 25(oh)d levels and dietary vitamin d intake with the risk of hypertension .
the results showed that there is a significant inverse relationship between baseline circulating 25(oh)d levels and risk of hypertension incident in seven studies measuring serum 25(oh)d levels ( rr = 0.70 , 95% ci = 0.580.86 ) , but it is not significant in four studies examining the dietary vitamin d intake ( rr = 1.00 , 95% ci = 0.951.05 ) .
moreover , dose - response analysis indicated that per 10 ng / ml increment in circulating 25(oh)d levels , the hypertension risk was reduced by 12% .
a systematic literature review and meta - analysis of all observational studies was conducted on data published up to early 2014 on vitamin d status and risk of hypertension .
there was no increment in hypertension risk in older ages with vitamin d deficiency , but high level of vitamin d showed significant association with risk of hypertension in younger females ( rr = 0.36 [ 0.180.72 ] , or = 0.62 [ 0.440.87 ] ) .
osteoporosis is associated with abnormalities of mineral homeostasis that can result in progression of bone loss , impaired bone microarchitecture , and consequently greater risk of fragility and fracture .
fractures , especially hip fractures , are common among postmenopausal women contributing to morbidity and mortality considerably . it has also been reported that the rate of inadequate vitamin d levels is high in postmenopausal women suggesting existence of a link between vitamin d deficiency and osteoporosis . there is evidence associating the existence of vdrs within the three major bone cell types including osteoblasts , osteocytes , and osteoclasts .
it regulates the serum calcium and phosphorus values by affecting their metabolism and absorption in bone , gut , and kidneys . on the other hand , vitamin d deficiency can also cause low bone mineral density via secondary hyperparathyroidism
moreover , it has been proposed that 1,25(oh)2d can stimulate the differentiation of osteoblasts and osteoclastogenesis .
nonetheless , the results of observational studies and clinical trials examining the effects of vitamin d supplementation on bone mineral density and fractures have been inconsistent .
furthermore , the controversy regarding the optimal concentrations of 25(oh)d for optimizing skeletal health has been yet remained .
the review study summarizing the recent recommendations on vitamin d by the international osteoporosis foundation ( iof ) , the institute of medicine , and the us endocrine society suggests that vitamin d3 or vitamin d2 supplements should be consumed at a dose of 800 iu / day among postmenopausal women for prevention of osteoporosis , falls , and fractures . according to the institute of medicine recommendation , a minimal serum 25(oh)d threshold of 20
ng / ml ( 50 nmol / l ) is needed for prevention of vitamin d deficiency . on the other hand ,
the iof and the us endocrine society recommend for prevention of falls and fracture , serum 25(oh)d levels should be higher threshold of 30 ng / ml ( 75 nmol / l ) . similarly , in another review is recommend that serum 25(oh)d level more than 30 ng / ml is suitable for bone health . furthermore , it has suggested that vitamin d supplementation in osteoporotic patients with vitamin d deficiency can reduce the fractures incidence through increment of bone mineral density and reduction of falls .
based on the findings of a meta - analysis included 31,022 persons ( 91% women ) , high - dose vitamin d supplementation ( 800 iu / day ) resulted in favorable reduction of hip fracture risk ( 30% ) and any nonvertebral fracture risk ( 14% ) among subjects aged 65 years .
the meta - analysis of 23 studies including 4082 participants ( 92% women ) was conducted to assess whether vitamin d supplementation can affect bone mineral density .
this analysis did not show any beneficial effect from vitamin d supplementation on bone density .
however , among five sites including lumbar spine , femoral neck , total hip , trochanter , total body , or forearm , a small but significant increase in bone density at the femoral neck was only observed ( mean difference = 0.8 , 95% ci = 0.21.4 ) .
another systematic review evaluated the results of six trials regarding calcitriol therapy alone and five trials on calcitriol therapy combined with other antiosteoporotic agents in elderly osteoporotic men and women .
this study suggested that calcitriol can reduce bone turnover markers and improve bone mineral density and muscle strength in short - term treatment without side effects .
however , it was observed that combination of calcitriol with various other therapeutic bone agents compared to calcitriol monotherapy can lead to more significant beneficial effects on fracture risk , bone pain , and bone mineral density in osteoporosis treatment .
breast cancer is considered a common disease and a leading cause of mortality in women .
it has been estimated that there are approximately 1.4 million new cases of breast cancer and over 450,000 mortality annually .
there are several well - established risk factors for breast cancer such as age , gender , density of breast tissue , parity , genetic , and alcohol use .
vitamin d plays the important roles in the mammary gland through regulation of calcium transport during lactation , differentiation hormones , and milk protein production .
the complex of vitamin d and vdrs in the normal breast epithelial cells can regulate transcription of more than sixty genes that are responsible for effects of antiproliferative , prodifferentiating , antimetastatic , and proapoptotic on cells .
it has been suggested that vitamin d can lead to the decrease in benign epithelial proliferation disorders and subsequently the breast cancer risk through reduction of breast mammographic density and antiproliferation and prodifferentiation activities .
although evidence from experimental and laboratory studies has generally shown an association between higher vitamin d levels and lower breast cancer risk , the results of human researches are somewhat controversial .
reviewed the studies examining the association between breast cancer and vitamin d from different sources ( skin synthesis or food or supplementation ) .
they suggested that elevated serum 25(oh)d levels through the sun exposure as well as dietary intake and an over 400 iu / day vitamin d supplementation were associated with a reduced risk of breast cancer .
similar findings were also reported in a pooled analysis on the 11 epidemiological studies regarding the relationship between levels of serum 25(oh)d and breast cancer risk . it was observed that individuals in the highest quintile versus the lowest quintile of serum 25(oh)d had a reduction in risk of breast cancer ( odds ratio [ or ] = 0.63 , 95% confidence interval [ ci ] = 0.470.80 ) .
on the other hand , this study reported that there was an approximately 10% reduction in risk of breast cancer followed by every 10 ng / ml increase in serum 25(oh)d concentration .
another meta - analysis by maalmi et al . including five prospective cohort studies during a follow - up of 2.724 years has been conducted to evaluate the association between serum 25(oh)d levels and survival among patients with breast cancer .
they observed that patients with high 25(oh)d levels had a significant reduced risk of overall mortality ( hazard ratio [ hr ] = 0.62 , 95% ci = 0.490.78 ) and breast cancer - specific mortality ( hr = 0.57 , 95% ci = 0.380.84 ) compared to patients with low 25(oh)d levels .
furthermore , dose - response analyses demonstrated that the increase in 25(oh)d by 20 nmol / l leads to reduce in overall ( hr = 0.82 , 95% ci = 0.750.88 ) and breast cancer - specific ( hr = 0.82 , 95% ci = 0.710.93 ) mortality .
however , this significant association between vitamin d and risk of breast cancer in pervious reviews has not been completely confirmed by other researches .
a meta - analysis by comparing the high and low total vitamin d intake showed that there is a significant association between vitamin d intake and breast cancer risk in cohort studies ( relative risk [ rr ] = 0.90 , 95% ci = 0.830.98 ) but not in the case control studies ( rr = 0.95 , 95% ci = 0.691.32 ) .
in addition , when subgroup analysis was conducted according to menopausal status , there was a significant association between vitamin d intake and breast cancer risk in the premenopausal women ( rr = 0.83 , 95% ci = 0.730.95 ) . on the other hand , no significant inverse relationship between circulating 25(oh)d levels and risk of breast cancer
furthermore , the findings of dose - response meta - analysis comprising 5206 cases of breast cancer and 6450 controls demonstrated that there was a marginal significant inverse association between circulating 25(oh)d and risk of breast cancer ( rr/5 ng / ml = 0.99 , 95% ci = 0.971.00 ) .
moreover , this meta - analysis revealed that menopause status can be affected on association between plasma 25(oh)d and breast cancer risk .
although the inverse relationship between circulating 25(oh)d and risk of breast cancer was observed in the postmenopausal women ( rr/5 ng / ml = 0.97 , 95% ci = 0.931.00 ) , there was no dose - response association among premenopausal women ( rr/5 ng / ml = 1.01 , 95% ci = 0.981.04 ) .
however , no reduction in risk of postmenopausal breast cancer per 5 ng / ml increase in 25(oh)d was observed above 35 ng / ml of 25(oh)d concentration .
the results of cohorts participating in the chances consortium showed that there was no association between lower 25(oh)d concentrations and increment of most cancers .
however , there was some evidence of increased breast cancer risk with higher 25(oh)d concentrations .
several risk factors have been recognized for these cancers such as old age , family history , high estrogen and low progesterone levels , nulliparity , and obesity .
the vdrs have been detected in endometrial and ovarian cell lines which mediate the role of 1,25(oh)2d in these tissues .
moreover , it has been suggested that 1,25(oh)2d can lead to inhibition of cell proliferation and induction of apoptosis in the ovarian cancer cells through down - regulation of telomerase activity .
although these biological reasons suggest that vitamin d may associate with the incidence and mortality of ovarian and endometrial cancers , the exact role of vitamin d in the etiology of these cancers has remained controversial .
the results of the studies that conducted in this field are not consistent . in a systematic review ,
the evidence related to association between ovarian cancer occurrence or mortality with vitamin d levels was evaluated .
although there was a reductions in the incidence or mortality with increased latitude , sunlight , or dietary / supplement vitamin d intake in the approximately half of the ecologic and case control studies , the other half case control and cohort studies reported no significant associations .
this systematic review suggests that there is no strong evidence regarding whether the increased vitamin d levels can reduce the risk of ovarian cancer incidence or mortality . in a nested case
control study , including 830 endometrial cancer cases from seven cohorts , no associations were observed between 25(oh)d concentration and endometrial cancers risk .
the results regarding the association between circulating 25(oh)d and endometrial cancer risk represented that there was a nonsignificant overall ors associated with concentrations of < 25
nmol / l ( 0.98 , 95% ci = 0.711.35 ) to compare with the reference category ( 5075
nmol / l ) . indeed , these findings did not support the protective role of vitamin d against the endometrial cancer . in another meta - analysis including 883 cases of ovarian cancer , the association between 25(oh)d and the ovarian cancer risk was assessed .
although in the seven studies , a tentatively reduced risk of ovarian cancer incidence was observed , there was no significant inverse relationship in pooled analyses ( rr = 0.83 , 95% ci = 0.631.08 , p = 0.166 ) for an increase levels of circulating 25(oh)d by 20 ng / ml .
hypertension is considered a prevalent disorder worldwide as well as among the iranian population which imposes a substantial burden on the health system .
old age , genetics , stressful lifestyle , obesity , etc . , have been recognized as various risk factors contributing to hypertension .
although vitamin d deficiency is another influential factor regarding high blood pressure ( bp ) , the role of serum vitamin d levels on hypertension remained not clear .
negative regulation of the renin gene , direct effects on vascular function through existence of 1-hydroxylase enzyme in the endothelial and vascular smooth muscle cells , and playing an important role in calcium metabolism are several potential mechanisms associating the regulation of vitamin d on bp which are not firmly established .
indeed , it has been assumed that vitamin d deficiency can promote the secondary hyperparathyroidism , increment the aldosterone secretion , and stimulate the renin - angiotensin system .
although a number of observational and epidemiologic researches have proposed that vitamin d deficiency can be associated with hypertension , in some trials , there are no convincing results representing that vitamin d supplementation has a protective role in hypertension .
liu et al . reviewed the evidence associating the effects of vitamin d on bp in postmenopausal women .
they found a direct association between low vitamin d status and hypertension in observational studies .
this review suggested that in hypertensive patients with vitamin d deficiency , vitamin d supplementation can be more effective .
similar findings were also reported in another review evaluating the association between vitamin d and the risk of developing elevated bp .
although there were strong observational evidence representing the association between vitamin d deficiency and hypertension , clinical trials have yielded inconclusive results .
a meta - analysis of 46 trials which comprised 4541 subjects was conducted to assess whether vitamin d supplementation can reduce bp .
the results found no significant effect of vitamin d supplementation on systolic ( effect size = 0.0 , 95% ci = 0.80.8 mmhg ) or diastolic bp ( effect size= 0.1 , 95% ci = 0.60.5 mmhg ) .
another systematic review and meta - analysis studied the evidence of prospective studies that investigated the associations of circulating 25(oh)d levels and dietary vitamin d intake with the risk of hypertension .
the results showed that there is a significant inverse relationship between baseline circulating 25(oh)d levels and risk of hypertension incident in seven studies measuring serum 25(oh)d levels ( rr = 0.70 , 95% ci = 0.580.86 ) , but it is not significant in four studies examining the dietary vitamin d intake ( rr = 1.00 , 95% ci = 0.951.05 ) .
moreover , dose - response analysis indicated that per 10 ng / ml increment in circulating 25(oh)d levels , the hypertension risk was reduced by 12% . a systematic literature review and meta - analysis of all observational studies
was conducted on data published up to early 2014 on vitamin d status and risk of hypertension .
there was no increment in hypertension risk in older ages with vitamin d deficiency , but high level of vitamin d showed significant association with risk of hypertension in younger females ( rr = 0.36 [ 0.180.72 ] , or = 0.62 [ 0.440.87 ] ) .
osteoporosis is associated with abnormalities of mineral homeostasis that can result in progression of bone loss , impaired bone microarchitecture , and consequently greater risk of fragility and fracture .
fractures , especially hip fractures , are common among postmenopausal women contributing to morbidity and mortality considerably .
it has also been reported that the rate of inadequate vitamin d levels is high in postmenopausal women suggesting existence of a link between vitamin d deficiency and osteoporosis .
there is evidence associating the existence of vdrs within the three major bone cell types including osteoblasts , osteocytes , and osteoclasts .
it regulates the serum calcium and phosphorus values by affecting their metabolism and absorption in bone , gut , and kidneys . on the other hand ,
moreover , it has been proposed that 1,25(oh)2d can stimulate the differentiation of osteoblasts and osteoclastogenesis .
nonetheless , the results of observational studies and clinical trials examining the effects of vitamin d supplementation on bone mineral density and fractures have been inconsistent .
furthermore , the controversy regarding the optimal concentrations of 25(oh)d for optimizing skeletal health has been yet remained .
the review study summarizing the recent recommendations on vitamin d by the international osteoporosis foundation ( iof ) , the institute of medicine , and the us endocrine society suggests that vitamin d3 or vitamin d2 supplements should be consumed at a dose of 800 iu / day among postmenopausal women for prevention of osteoporosis , falls , and fractures .
according to the institute of medicine recommendation , a minimal serum 25(oh)d threshold of 20 ng / ml ( 50 nmol / l ) is needed for prevention of vitamin d deficiency . on the other hand ,
the iof and the us endocrine society recommend for prevention of falls and fracture , serum 25(oh)d levels should be higher threshold of 30 ng / ml ( 75 nmol / l ) . similarly , in another review is recommend that serum 25(oh)d level more than 30 ng / ml is suitable for bone health . furthermore , it has suggested that vitamin d supplementation in osteoporotic patients with vitamin d deficiency can reduce the fractures incidence through increment of bone mineral density and reduction of falls .
based on the findings of a meta - analysis included 31,022 persons ( 91% women ) , high - dose vitamin d supplementation ( 800 iu / day ) resulted in favorable reduction of hip fracture risk ( 30% ) and any nonvertebral fracture risk ( 14% ) among subjects aged 65 years .
the meta - analysis of 23 studies including 4082 participants ( 92% women ) was conducted to assess whether vitamin d supplementation can affect bone mineral density .
this analysis did not show any beneficial effect from vitamin d supplementation on bone density .
however , among five sites including lumbar spine , femoral neck , total hip , trochanter , total body , or forearm , a small but significant increase in bone density at the femoral neck was only observed ( mean difference = 0.8 , 95% ci = 0.21.4 ) .
another systematic review evaluated the results of six trials regarding calcitriol therapy alone and five trials on calcitriol therapy combined with other antiosteoporotic agents in elderly osteoporotic men and women .
this study suggested that calcitriol can reduce bone turnover markers and improve bone mineral density and muscle strength in short - term treatment without side effects .
however , it was observed that combination of calcitriol with various other therapeutic bone agents compared to calcitriol monotherapy can lead to more significant beneficial effects on fracture risk , bone pain , and bone mineral density in osteoporosis treatment .
the overall results of the recent reviews suggest that vitamin d supplementation and high 25(oh)d levels can be beneficial in decreased risk of breast cancer as a one of the most common cancers among women
. however , there is no strong evidence to support the existence of a relationship between vitamin d and ovarian or endometrial cancers .
indeed , in numerous trials and observational studies have not been observed that vitamin d exposures can reduce the risk of these cancers .
furthermore , the results on the effects of vitamin d on hypertension were inconsistent ; a number of surveys especially observational studies have shown an association between vitamin d and hypertension , but in some other trials , there is no evidence regarding effectiveness of vitamin d as an agent for lowering bp .
moreover , the findings associating the impact of vitamin d on osteoporosis were more definitive and most studies have represented that vitamin d can have beneficial effects in osteoporosis .
moreover , it has been reported that vitamin d along with therapeutic bone agents has a more considerable role in osteoporosis treatment .
many possible reasons may be responsible for different findings of various studies in this regards .
there are many variables that can affect the vitamin d status including solar radiation , latitude , dietary and biochemical factors , supplements use , weight , total body fat percentage , age , and month of blood sampling , and the adjustment for these confounders may be different among studies causing various conclusions .
for instance , if the seasonal variation in 25(oh)d concentrations is not taken into account , it can lead to misclassification of vitamin d status .
in addition , the existence of other potential confounders such as publication bias , varying assessment methods , and measurement errors may potentially lead to biases and different results .
it has proposed that reduced estrogen can lead to decrease in vitamin d activation and vdr expression .
therefore , menopause status can be another factor associating with vitamin d status that many studies did not enable to adjust the effect of menopausal status on association between vitamin d and risk of diseases .
this review tries to summarize the result of most recent systematic review and meta - analysis regarding prevalent diseases among female population . however , there are some limitations in our studies .
we included only most recent systematic review and meta - analysis studies in our article and it did not conduct systematically .
further researches need to be conducted to find the exact effect of vitamin d , especially on endometrial and ovarian cancers .
although findings from the many studies have been represented that adequate vitamin d can play a protective role in the incidence and development of breast cancer , hypertension , and osteoporosis as well as sometimes in ovarian and endometrial cancers , these results have not yet been confirmed in the number of researches .
therefore , we can not make definitive deductions yet and more well - designed clinical trials and cohort studies considering all potential confounder factors with long follow - up period are needed to determine definite protective effect of vitamin d against these diseases and to find the optimal doses of vitamin d intake .
all authors approved the final version of the manuscript , and agreed for all aspects of the work .
Output:
| background : vitamin d has a wide range of physiological functions in skeletal and nonskeletal tissues which may play a role in many diseases . the aim of this study was to evaluate the recent evidence regarding the effects of vitamin d on several health outcomes in women including breast cancer , ovarian and endometrial cancers , hypertension , and osteoporosis.materials and methods : we searched pubmed and google scholar databases through march 2016 .
we included the most current systematic reviews and meta - analyses assessing the associations of vitamin d intake and/or serum 25-hydroxyvitamin d ( 25(oh)d ) levels with the risk of incidence of breast cancer , ovarian and endometrial cancers , hypertension , and osteoporosis.results:many studies have represented that vitamin d supplementation and high 25(oh)d levels can decrease the risk of breast cancer occurrence or mortality . however , there is no strong evidence to support the existence of a relationship between vitamin d and ovarian or endometrial cancers .
furthermore , the results regarding the effects of vitamin d on hypertension were inconsistent .
although observational studies have shown an association between vitamin d and hypertension , there is no evidence regarding effectiveness of vitamin d in lowering blood pressure in several clinical trials . on the other hand ,
the findings associating the impact of vitamin d on osteoporosis were more definitive and most studies have represented that vitamin d may have beneficial effects on osteoporosis.conclusion:although the adequate vitamin d level can play a protective role in the incidence and development of breast cancer , hypertension , and osteoporosis , there is limited evidence regarding ovarian and endometrial cancers . |
PubmedSumm118747 | ***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: inclusion criteria included age 1230 years , clinical diagnosis of type 1 diabetes of at least 1 year s duration , current use of insulin pump therapy , a1c < 9% ( < 75 mmol / mol ) , bmi < 95th percentile for age and sex , normal hematocrit and serum creatinine levels , no other chronic medical condition ( except treated hypothyroidism ) , and no medications ( other than insulin ) known to affect blood glucose levels ; also , female subjects could not be pregnant or lactating .
after a complete explanation of the study protocol , written informed consent was obtained in subjects 18 years ; in subjects < 18 years , both an adolescent assent and parent permission were obtained .
, crossover study design was used to compare overnight blood glucose control during ol and cl therapy on days with and without antecedent afternoon exercise .
we hypothesized that cl insulin delivery would be superior to ol control in preventing nh , especially on nights after antecedent afternoon exercise , and that cl control would be able to maintain a higher proportion of blood glucose levels within the 70180 mg / dl target range , even in the face of afternoon exercise .
all study subjects were admitted to the yale hospital research unit ( hru ) on two occasions for 48-h assessments ( study days 1 and 2 ) of glycemic control using either cl insulin delivery or conventional ol insulin pump therapy in random order ( fig .
, subjects underwent a treadmill exercise protocol in the afternoon on one of the 24-h periods ( exercise day ) and rested throughout the other 24-h period ( sedentary day)also in random order .
meals ( self - selected by study subjects from a hospital menu ) were identical during both admissions and on both study days were provided at 8:00 a.m. , noon , and 5:00 p.m .. carbohydrate intake averaged 93 24 g / meal ( 90 22 g breakfast , 93 26 g lunch , and 96 27 g dinner ) and ranged between 42 and 127 g. no snacks were allowed , except for treatment of hypoglycemia .
all subjects were admitted to the hru in the afternoon prior to study day 1 .
intravenous catheters were placed for measurement of reference plasma glucose levels , which were measured at the bedside every 30 min by the ysi 2300 glucose analyzer ( ysi life sciences , yellow springs , oh ) . in 10 of the 12 subjects ,
blood samples were obtained for determination of plasma insulin levels every 30 min between 10:00 p.m. and 6:00 a.m. patients were treated with 1530 g oral carbohydrates if reference blood glucose fell below 60 mg / dl . during both admissions ,
subjects were able to move about their rooms or the hallway , but vigorous physical activity was not permitted , except during the exercise protocol . on the afternoon of admission to the hru ,
a new infusion set was inserted for use with their home insulin pump . during this admission ,
subjects were advised to continue their usual care ; therefore , subjects tested blood glucose levels on a glucose meter as desired , determined how much insulin to bolus for meals , and made their usual adjustments ( if any ) to basal insulin infusion rates during exercise . on the afternoon of admission to the hru , two continuous glucose sensors ( the study sensor and a back - up sensor )
were inserted in the subcutaneous space of the anterior abdominal wall and calibrated ; a new insulin infusion set was placed in the hip / buttocks , and the home insulin pump was replaced by the study pump ( medtronic paradigm 715 ) .
insulin usage over the prior 37 days was used to determine algorithm parameters that were programmed into the study computer .
a run - in period of cl control was initiated at ~9:00 p.m. to achieve stable , target glucose levels at the start of the cl experiments the next morning ( 7:00 a.m. of study day 1 ) .
the hybrid cl system used in this study consisted of four components : a medtronic paradigm 715 insulin pump , a medtronic minilink real - time transmitter ( mmt-7703 ) adapted for 1-min transmission , a medtronic sof - sensor ( mmt-7002/7003 ) continuous glucose sensor , and the medtronic external pid algorithm , which uses a pid algorithm modified to include insulin feedback ( 1820 ) . with this system ,
glucose sensor signals were transmitted every minute from a radiofrequency transmitter and delivered insulin commands to the pump by radiofrequency signaling .
the algorithm s target glucose level was set to 120 mg / day during the day and night .
details regarding the algorithm parameters and calibration procedures have previously been reported ( 21 ) . as described previously ( 11 ) , during cl control subjects also received a small manual priming bolus of 0.05 units / kg ( average premeal bolus 3.1 1.2 units ) at the start of the meals .
although the system operates off of one sensor , the second sensor was available in the event of a sensor malfunction .
sensors were calibrated at the start of cl control and whenever reference / sensor errors exceeded 20% .
sensor accuracy , defined as mean absolute relative deviation between sensor and reference blood glucose levels , was 10.1 2.0% during the cl studies . on the afternoon of the first admission
, subjects underwent an abbreviated exercise tolerance test to determine the treadmill settings needed to obtain target heart rates .
the target heart rate was calculated to approximate 5055% maximal effort ( equivalent to 6570% maximum heart rate ) , where maximum heart rate was calculated as 220 subject age ( in years ) . as in the direcnet study
( 1 ) , exercise sessions were scheduled to begin at 3:00 p.m. to simulate typical after - school activity .
the exercise session consisted of four 15-min exercise periods interspersed with three 5-min rest periods .
reference blood glucose levels were measured just prior to the start of exercise and at the end of each 15-min exercise period .
on the day of exercise , supplemental carbohydrate was administered if starting blood glucose was < 120 mg / dl .
pre - exercise per - protocol supplemental carbohydrate was needed in 30% of subjects while on cl therapy ( range of carbohydrates 1575 g ) , with double the number of subjects requiring supplemental carbohydrates during the ol exercise condition ( range of carbohydrates 15120 g ) . during rest periods , subjects received 1530 g carbohydrate snack if reference blood glucose was < 80 mg / dl , and blood glucose levels had to be 80 mg / dl in order to resume exercise . reference plasma glucose concentrations were used to compare differences in glucose control between the two treatment conditions cl and ol . the overnight period was defined as 10:00 p.m. to 6:00 a.m. hypoglycemia was defined as reference blood glucose < 70 mg / dl . a treatable hypoglycemic event was defined as a reference blood glucose level < 60 mg / dl .
episodes of treatable hypoglycemia needed to be separated by more than 30 min to be counted as two discrete events .
the proportions of overnight blood glucose values < 70 , 70180 , and > 180 mg / dl were also compared under ol and cl control .
statistical comparisons between cl and ol groups were accomplished with paired t tests for normally distributed data and wilcoxon matched pairs signed rank tests for nonnormally distributed data .
comparison of reference blood glucose divided into predefined glycemic categories ( < 70 , 70180 , and > 180 mg / dl ) was achieved using a test .
calculations were performed using graphpad prism 5 ( graphpad software , san diego , ca ) .
inclusion criteria included age 1230 years , clinical diagnosis of type 1 diabetes of at least 1 year s duration , current use of insulin pump therapy , a1c < 9% ( < 75 mmol / mol ) , bmi < 95th percentile for age and sex , normal hematocrit and serum creatinine levels , no other chronic medical condition ( except treated hypothyroidism ) , and no medications ( other than insulin ) known to affect blood glucose levels ; also , female subjects could not be pregnant or lactating .
after a complete explanation of the study protocol , written informed consent was obtained in subjects 18 years ; in subjects < 18 years , both an adolescent assent and parent permission were obtained .
a randomized , crossover study design was used to compare overnight blood glucose control during ol and cl therapy on days with and without antecedent afternoon exercise .
we hypothesized that cl insulin delivery would be superior to ol control in preventing nh , especially on nights after antecedent afternoon exercise , and that cl control would be able to maintain a higher proportion of blood glucose levels within the 70180 mg / dl target range , even in the face of afternoon exercise .
all study subjects were admitted to the yale hospital research unit ( hru ) on two occasions for 48-h assessments ( study days 1 and 2 ) of glycemic control using either cl insulin delivery or conventional ol insulin pump therapy in random order ( fig .
, subjects underwent a treadmill exercise protocol in the afternoon on one of the 24-h periods ( exercise day ) and rested throughout the other 24-h period ( sedentary day)also in random order .
meals ( self - selected by study subjects from a hospital menu ) were identical during both admissions and on both study days were provided at 8:00 a.m. , noon , and 5:00 p.m .. carbohydrate intake averaged 93 24 g / meal ( 90 22 g breakfast , 93 26 g lunch , and 96 27 g dinner ) and ranged between 42 and 127 g. no snacks were allowed , except for treatment of hypoglycemia .
all subjects were admitted to the hru in the afternoon prior to study day 1 .
intravenous catheters were placed for measurement of reference plasma glucose levels , which were measured at the bedside every 30 min by the ysi 2300 glucose analyzer ( ysi life sciences , yellow springs , oh ) . in 10 of the 12 subjects ,
blood samples were obtained for determination of plasma insulin levels every 30 min between 10:00 p.m. and 6:00 a.m. patients were treated with 1530 g oral carbohydrates if reference blood glucose fell below 60 mg / dl . during both admissions ,
subjects were able to move about their rooms or the hallway , but vigorous physical activity was not permitted , except during the exercise protocol . on the afternoon of admission to the hru ,
a new infusion set was inserted for use with their home insulin pump . during this admission ,
subjects were advised to continue their usual care ; therefore , subjects tested blood glucose levels on a glucose meter as desired , determined how much insulin to bolus for meals , and made their usual adjustments ( if any ) to basal insulin infusion rates during exercise . on the afternoon of admission to the hru , two continuous glucose sensors ( the study sensor and a back - up sensor )
were inserted in the subcutaneous space of the anterior abdominal wall and calibrated ; a new insulin infusion set was placed in the hip / buttocks , and the home insulin pump was replaced by the study pump ( medtronic paradigm 715 ) .
insulin usage over the prior 37 days was used to determine algorithm parameters that were programmed into the study computer .
after dinner , a run - in period of cl control was initiated at ~9:00 p.m. to achieve stable , target glucose levels at the start of the cl experiments the next morning ( 7:00 a.m. of study day 1 ) .
the hybrid cl system used in this study consisted of four components : a medtronic paradigm 715 insulin pump , a medtronic minilink real - time transmitter ( mmt-7703 ) adapted for 1-min transmission , a medtronic sof - sensor ( mmt-7002/7003 ) continuous glucose sensor , and the medtronic external pid algorithm , which uses a pid algorithm modified to include insulin feedback ( 1820 ) . with this system ,
glucose sensor signals were transmitted every minute from a radiofrequency transmitter and delivered insulin commands to the pump by radiofrequency signaling .
the algorithm s target glucose level was set to 120 mg / day during the day and night .
details regarding the algorithm parameters and calibration procedures have previously been reported ( 21 ) . as described previously ( 11 ) , during cl control subjects also received a small manual priming bolus of 0.05 units / kg ( average premeal bolus 3.1 1.2 units ) at the start of the meals .
although the system operates off of one sensor , the second sensor was available in the event of a sensor malfunction .
sensors were calibrated at the start of cl control and whenever reference / sensor errors exceeded 20% .
sensor accuracy , defined as mean absolute relative deviation between sensor and reference blood glucose levels , was 10.1 2.0% during the cl studies .
on the afternoon of the first admission , subjects underwent an abbreviated exercise tolerance test to determine the treadmill settings needed to obtain target heart rates .
the target heart rate was calculated to approximate 5055% maximal effort ( equivalent to 6570% maximum heart rate ) , where maximum heart rate was calculated as 220 subject age ( in years ) . as in the direcnet study
( 1 ) , exercise sessions were scheduled to begin at 3:00 p.m. to simulate typical after - school activity .
the exercise session consisted of four 15-min exercise periods interspersed with three 5-min rest periods .
reference blood glucose levels were measured just prior to the start of exercise and at the end of each 15-min exercise period . on the day of exercise , supplemental carbohydrate was administered if starting blood glucose was < 120 mg / dl .
pre - exercise per - protocol supplemental carbohydrate was needed in 30% of subjects while on cl therapy ( range of carbohydrates 1575 g ) , with double the number of subjects requiring supplemental carbohydrates during the ol exercise condition ( range of carbohydrates 15120 g ) . during rest periods , subjects received 1530 g carbohydrate snack if reference blood glucose was < 80 mg / dl , and blood glucose levels had to be 80 mg / dl in order to resume exercise .
on the afternoon of admission to the hru , a new infusion set was inserted for use with their home insulin pump . during this admission ,
subjects were advised to continue their usual care ; therefore , subjects tested blood glucose levels on a glucose meter as desired , determined how much insulin to bolus for meals , and made their usual adjustments ( if any ) to basal insulin infusion rates during exercise .
on the afternoon of admission to the hru , two continuous glucose sensors ( the study sensor and a back - up sensor ) were inserted in the subcutaneous space of the anterior abdominal wall and calibrated ; a new insulin infusion set was placed in the hip / buttocks , and the home insulin pump was replaced by the study pump ( medtronic paradigm 715 ) .
insulin usage over the prior 37 days was used to determine algorithm parameters that were programmed into the study computer .
subjects were continued on ol control for dinner . after dinner , a run - in period of cl control was initiated at ~9:00 p.m. to achieve stable , target glucose levels at the start of the cl experiments the next morning ( 7:00 a.m. of study day 1 ) .
the hybrid cl system used in this study consisted of four components : a medtronic paradigm 715 insulin pump , a medtronic minilink real - time transmitter ( mmt-7703 ) adapted for 1-min transmission , a medtronic sof - sensor ( mmt-7002/7003 ) continuous glucose sensor , and the medtronic external pid algorithm , which uses a pid algorithm modified to include insulin feedback ( 1820 ) . with this system ,
glucose sensor signals were transmitted every minute from a radiofrequency transmitter and delivered insulin commands to the pump by radiofrequency signaling .
the algorithm s target glucose level was set to 120 mg / day during the day and night .
details regarding the algorithm parameters and calibration procedures have previously been reported ( 21 ) . as described previously ( 11 ) , during cl control subjects also received a small manual priming bolus of 0.05 units / kg ( average premeal bolus 3.1 1.2 units ) at the start of the meals .
although the system operates off of one sensor , the second sensor was available in the event of a sensor malfunction .
sensors were calibrated at the start of cl control and whenever reference / sensor errors exceeded 20% .
sensor accuracy , defined as mean absolute relative deviation between sensor and reference blood glucose levels , was 10.1 2.0% during the cl studies .
on the afternoon of the first admission , subjects underwent an abbreviated exercise tolerance test to determine the treadmill settings needed to obtain target heart rates .
the target heart rate was calculated to approximate 5055% maximal effort ( equivalent to 6570% maximum heart rate ) , where maximum heart rate was calculated as 220 subject age ( in years ) . as in the direcnet study ( 1 ) , exercise sessions were scheduled to begin at 3:00 p.m. to simulate typical after - school activity .
the exercise session consisted of four 15-min exercise periods interspersed with three 5-min rest periods .
reference blood glucose levels were measured just prior to the start of exercise and at the end of each 15-min exercise period . on the day of exercise ,
pre - exercise per - protocol supplemental carbohydrate was needed in 30% of subjects while on cl therapy ( range of carbohydrates 1575 g ) , with double the number of subjects requiring supplemental carbohydrates during the ol exercise condition ( range of carbohydrates 15120 g ) . during rest periods , subjects received 1530 g carbohydrate snack if reference blood glucose was < 80 mg / dl , and blood glucose levels had to be 80 mg / dl in order to resume exercise .
reference plasma glucose concentrations were used to compare differences in glucose control between the two treatment conditions cl and ol . the overnight period was defined as 10:00 p.m. to 6:00 a.m. hypoglycemia was defined as reference blood glucose < 70 mg / dl .
a treatable hypoglycemic event was defined as a reference blood glucose level < 60 mg / dl .
episodes of treatable hypoglycemia needed to be separated by more than 30 min to be counted as two discrete events .
the proportions of overnight blood glucose values < 70 , 70180 , and > 180 mg / dl were also compared under ol and cl control .
statistical comparisons between cl and ol groups were accomplished with paired t tests for normally distributed data and wilcoxon matched pairs signed rank tests for nonnormally distributed data .
comparison of reference blood glucose divided into predefined glycemic categories ( < 70 , 70180 , and > 180 mg / dl ) was achieved using a test .
calculations were performed using graphpad prism 5 ( graphpad software , san diego , ca ) .
thirteen subjects were recruited into the study . however , one subject withdrew consent prior to any study procedures being conducted .
the 12 subjects ( 5 females ) who completed the study were aged 16.8 3.6 years ( range 1226 years ) and had diabetes duration of 5.7 3.7 years ( range 111.5 ) and an a1c level of 7.4 0.6% ( 75 17
twenty - four hour mean blood glucose levels were modestly lower during ol compared with cl control on both sedentary ( 135 46 vs. 140 47 mg / dl , p = 0.02 ) and exercise ( 141 63 vs. 147 56 mg / dl , p = 0.04 ) days , but these differences disappeared when blood glucose levels < 70 mg / dl were removed from the analyses .
baseline blood glucose levels were similar at the start of the exercise protocol on both the cl ( 161 35 mg / dl ) and ol ( 181 80 mg / dl , p = 0.57 ) study days .
the mean nadir blood glucose values during exercise were also similar on both study days , and there was no difference in the number of treatments for hypoglycemia that were needed during exercise ( cl 5 vs. ol 6 , p = 0.82 ) .
predinner ( 5:00 p.m. ) and 10:00 p.m. blood glucose levels during cl control were similar to corresponding values during ol control ( supplementary table 1 ) , and there were no significant differences in the total amount of insulin delivered between 5:00 p.m. and 10:00 p.m. on cl exercise and ol exercise days . during ol control on sedentary days ,
the mean sd overnight blood glucose level was 126 37 mg / dl , with 87% of blood glucose levels within the 70180 mg / dl range and 4% of values < 70 mg / dl ( table 1 ) .
nevertheless , even lower mean blood glucose levels could be achieved with overnight cl control on sedentary days , with 98% of values between 70 and 180 mg / dl and only 1.5% of values
overnight glycemic control with ol vs. cl control as expected , antecedent afternoon exercise increased the frequency of low glucose levels to 11% during the night during ol control and the frequency of hyperglycemic values also rose ( table 1 ) . during cl treatment , excellent overnight glucose control was maintained despite antecedent afternoon exercise , with 91% of glucose values in the 70180 mg / dl range and only 5% < 70 mg / dl ( p < 0.0001 vs. ol ) . as insulin doses during cl therapy are based off of sensor glucose levels , mean sensor glucose levels were also calculated for the overnight period during both cl conditions and found to be similar to that derived from reference blood glucose data , except that on the cl exercise nights only 1% of sensor glucose readings were < 70 mg / dl compared with 5% of reference glucose levels . on the nights after exercise , there were 23 episodes of biochemical hypoglycemia ( reference blood glucose < 70 mg / dl ) for ol control compared with only 11 episodes for cl control ( p = 0.03 ) .
similarly , there were more than twice as many episodes of biochemical hypoglycemia detected on sedentary nights with ol control ( 8 episodes ) compared with cl control ( 3 episodes ) .
2 , there was a total of 14 episodes of treatable nh ( reference blood glucose < 60 mg / dl ) during ol control versus a total of only 2 episodes of treatable hypoglycemia on nights with cl control ( p = 0.04 ) . on nights after antecedent afternoon exercise
, there were eight episodes of treatable hypoglycemia in four subjects during ol control versus one episode during cl control .
episodes of overnight treatable hypoglycemia ( reference blood glucose < 60 mg / dl ) during ol and cl . on exercise days , six of the eight episodes of treatable hypoglycemia during ol therapy and the only episode of treatable hypoglycemia during cl control occurred between 10:00 p.m. and 2:00 a.m. , 711 h after starting afternoon exercise . while insulin delivery was fixed during this period of time during ol therapy , cl insulin delivery allowed for minute - to - minute alterations in the amount of insulin received . as demonstrated in fig .
3a , cl therapy was associated with lower insulin delivery between 10:00 p.m. and 2:00 a.m. compared with ol on nights after antecedent exercise ( mean sem , cl exercise 0.8 1.09 units / h vs. ol exercise 0.98 0.33 units / h ; p = 0.008 ) .
plasma insulin levels also tended to be lower on cl compared with ol control ( mean sem , cl exercise 15.57 7.3 u / ml vs. ol exercise 17.06 6.76 u / ml ; p = 0.06 ) ( fig .
3b ) during this time period . a : overnight insulin delivery in units / h 711 h postexercise ( 10:00 p.m. to 2:00 a.m. ) , with cl associated with lower insulin delivery ( p = 0.008 ) .
b : plasma insulin levels between 10:00 p.m. and 2:00 a.m. , with trend toward significance for lower plasma insulin levels on cl nights vs. ol nights ( p = 0.06 ) .
cl - e , cl exercise ( solid line ) ; ol - e , ol exercise ( dashed line ) .
twenty - four hour mean blood glucose levels were modestly lower during ol compared with cl control on both sedentary ( 135 46 vs. 140 47 mg / dl , p = 0.02 ) and exercise ( 141 63 vs. 147 56 mg / dl , p = 0.04 ) days , but these differences disappeared when blood glucose levels < 70 mg / dl were removed from the analyses .
baseline blood glucose levels were similar at the start of the exercise protocol on both the cl ( 161 35 mg / dl ) and ol ( 181 80 mg / dl , p = 0.57 ) study days .
the mean nadir blood glucose values during exercise were also similar on both study days , and there was no difference in the number of treatments for hypoglycemia that were needed during exercise ( cl 5 vs. ol 6 , p = 0.82 ) .
predinner ( 5:00 p.m. ) and 10:00 p.m. blood glucose levels during cl control were similar to corresponding values during ol control ( supplementary table 1 ) , and there were no significant differences in the total amount of insulin delivered between 5:00 p.m. and 10:00 p.m. on cl exercise and ol exercise days .
during ol control on sedentary days , the mean sd overnight blood glucose level was 126 37 mg / dl , with 87% of blood glucose levels within the 70180 mg / dl range and 4% of values
nevertheless , even lower mean blood glucose levels could be achieved with overnight cl control on sedentary days , with 98% of values between 70 and 180 mg / dl and only 1.5% of values < 70 mg / dl ( p < 0.0001 vs. ol ) .
overnight glycemic control with ol vs. cl control as expected , antecedent afternoon exercise increased the frequency of low glucose levels to 11% during the night during ol control and the frequency of hyperglycemic values also rose ( table 1 ) . during cl treatment , excellent overnight glucose control was maintained despite antecedent afternoon exercise , with 91% of glucose values in the 70180 mg / dl range and only 5% < 70 mg / dl ( p < 0.0001 vs. ol ) . as insulin doses during cl therapy are based off of sensor glucose levels , mean sensor glucose levels were also calculated for the overnight period during both cl conditions and found to be similar to that derived from reference blood glucose data , except that on the cl exercise nights only 1% of sensor glucose readings were < 70 mg / dl compared with 5% of reference glucose levels . on the nights after exercise
, there were 23 episodes of biochemical hypoglycemia ( reference blood glucose < 70 mg / dl ) for ol control compared with only 11 episodes for cl control ( p = 0.03 ) .
similarly , there were more than twice as many episodes of biochemical hypoglycemia detected on sedentary nights with ol control ( 8 episodes ) compared with cl control ( 3 episodes ) .
2 , there was a total of 14 episodes of treatable nh ( reference blood glucose < 60 mg / dl ) during ol control versus a total of only 2 episodes of treatable hypoglycemia on nights with cl control ( p = 0.04 ) . on nights after antecedent afternoon exercise
, there were eight episodes of treatable hypoglycemia in four subjects during ol control versus one episode during cl control .
episodes of overnight treatable hypoglycemia ( reference blood glucose < 60 mg / dl ) during ol and cl . on exercise days ,
six of the eight episodes of treatable hypoglycemia during ol therapy and the only episode of treatable hypoglycemia during cl control occurred between 10:00 p.m. and 2:00 a.m. , 711 h after starting afternoon exercise . while insulin delivery was fixed during this period of time during ol therapy , cl insulin delivery allowed for minute - to - minute alterations in the amount of insulin received .
3a , cl therapy was associated with lower insulin delivery between 10:00 p.m. and 2:00 a.m. compared with ol on nights after antecedent exercise ( mean sem , cl exercise 0.8 1.09 units / h vs. ol exercise 0.98 0.33 units / h ; p = 0.008 ) .
plasma insulin levels also tended to be lower on cl compared with ol control ( mean sem , cl exercise 15.57 7.3 u / ml vs. ol exercise 17.06 6.76 u / ml ; p = 0.06 ) ( fig .
a : overnight insulin delivery in units / h 711 h postexercise ( 10:00 p.m. to 2:00 a.m. ) , with cl associated with lower insulin delivery ( p = 0.008 ) .
b : plasma insulin levels between 10:00 p.m. and 2:00 a.m. , with trend toward significance for lower plasma insulin levels on cl nights vs. ol nights ( p = 0.06 ) .
cl - e , cl exercise ( solid line ) ; ol - e , ol exercise ( dashed line ) .
in this study , we used the same rigorous 75-min treadmill exercise protocol that was developed by direcnet to test whether feedback - controlled insulin delivery could respond to the delayed glucose - lowering effects of afternoon exercise and lower the risks of nh .
as in the direcnet study , the exercise protocol was started at 3:00 p.m. , since this is the time of the day when many youth with type 1 diabetes participate in sports and other physical activities .
( 4 ) and confirmed in our patients during ol control , the delayed glucose - lowering effects of afternoon exercise would be expected to peak 711 h after exercise or between 10:00 p.m. and 2:00 a.m. in this study .
as seen in our recent study with the medtronic cl system using the pid plus insulin feedback algorithm and the same 120 mg / dl target sensor glucose level ( 21 ) , overnight glucose control during cl insulin delivery was outstanding on sedentary days . indeed , 90% of reference blood glucose values were between 70 and 140 mg / dl , 98% were in the 70180 mg / dl , and only 1.5% were < 70 mg / dl a precision that could not be achieved during the overnight period on sedentary days during ol therapy . even more important , the cl system outperformed ol pump therapy in this group of very well - controlled adolescents and young adults on nights after afternoon exercise : the proportion of hypo- and hyperglycemic values was significantly lower during cl control , and the number of episodes of hypoglycemia that required treatment because of blood glucose levels < 60 mg / dl fell from eight during ol therapy to only one during cl control .
episodes of biochemical and treatable episodes of nh were reduced on exercise nights because feedback control of insulin delivery rates allowed the system to automatically reduce basal insulin delivery during the vulnerable 10:00 p.m. to 2:00 a.m. period .
it is also noteworthy that mean reference blood glucose levels during the overnight period with cl control during both sedentary and exercise days were nearly identical to the pid algorithm s 120 mg / dl target setting ( table 1 ) .
additionally , regardless of prior daytime activity level , the cl system achieved a similar proportion of time spent within a targeted range of 70180 mg / dl ( cl exercise vs. cl exercise : p = 0.23 ) .
thus , cl therapy was both safe and effective in allowing optimization of glycemic control under both sedentary and exercise conditions .
as per the direcnet protocol , during ol control in this study patients remained on the same overnight basal rates on both sedentary and exercise days . while many clinicians may recommend temporary reductions in overnight basal rates in pump - treated patients to reduce the risk of hypoglycemia on nights after afternoon exercise ,
there are no clear guidelines for the duration and extent of reduction in basal rates , which is likely to vary from patient to patient and depends on the type of exercise .
it is not surprising that previous reports have shown that use of this strategy often results in nocturnal hyperglycemia ( 22,23 ) .
the current study was conducted as a proof - of - concept assessment of the effects of exercise on cl performance , and our data provide compelling evidence regarding the effectiveness of cl insulin delivery in reducing the risk of nh regardless of prior daytime activity .
recently , the first outpatient testing of an artificial pancreas in a transitional setting of a camp demonstrated that use of such insulin delivery modalities can decrease nh while providing tighter glycemic control than could be achieved with sap therapy ( 24 ) . nevertheless , a number of obstacles remain before this technology can be safely used in the outpatient home setting .
the major obstacle that needs to be overcome is to minimize the risk of patient injury due to overdelivery of insulin because of a system malfunction . as cl insulin delivery
is determined by sensor glucose values , it is critical to have uninterrupted sensor data ; thus , in the current study , two sensors were placed so that should a sensor fail , the alternate sensor signal could be used and thus prevent placement of a new sensor .
development of orthogonal sensors or systems that have more than one electrochemical sensor may provide redundancy to the system without necessitating the placement of two sensors .
better sensor accuracy , greater integrity of radiofrequency transmissions , and enhanced ease of patient use are among the improvements that are needed to translate this technology into outpatient treatment . in the meantime
, reducing the risk of hypoglycemia by automatically reducing or temporarily suspending pump basal insulin infusion rates based on projected low glucose levels is an area of intense research interest .
our findings extend the findings of previous studies that sought to assess the effectiveness of cl systems on overnight glucose control in patients with type 1 diabetes . in those investigations ,
studies were carried out on sedentary days ( 1017 ) or days with shorter periods of physical activity ( 17,25,26 ) .
while the system could not decrease the rate of hypoglycemia that occurred during exercise , our data indicate that compared with ol therapy , cl insulin delivery is an effective means to ensure adequate glycemic control and reduce the risk of hypoglycemia in the overnight period , even on nights after vigorous and prolonged afternoon exercise .
it should also be noted that cl control markedly reduced but did not fully eliminate the incidence of nh during exercise and sedentary days .
thus , other approaches including improved algorithms or a bihormonal system that includes small rescue doses of glucagon ( 26 ) may still be needed to completely eliminate the problem of nh .
Output:
| objectiveafternoon exercise increases the risk of nocturnal hypoglycemia ( nh ) in subjects with type 1 diabetes .
we hypothesized that automated feedback - controlled closed - loop ( cl ) insulin delivery would be superior to open - loop ( ol ) control in preventing nh and maintaining a higher proportion of blood glucose levels within the target blood glucose range on nights with and without antecedent afternoon exercise.research design and methodssubjects completed two 48-h inpatient study periods in random order : usual ol control and cl control using a proportional - integrative - derivative plus insulin feedback algorithm .
each admission included a sedentary day and an exercise day , with a standardized protocol of 60 min of brisk treadmill walking to 6570% maximum heart rate at 3:00 p.m.resultsamong 12 subjects ( age 1226 years , a1c 7.4 0.6% ) , antecedent exercise increased the frequency of nh ( reference blood glucose < 60 mg / dl ) during ol control from six to eight events .
in contrast , there was only one nh event each on nights with and without antecedent exercise during cl control ( p = 0.04 vs. ol nights ) .
overnight , the percentage of glucose values in target range was increased with cl control ( p < 0.0001 ) .
insulin delivery was lower between 10:00 p.m. and 2:00 a.m. on nights after exercise on cl versus ol , p = 0.008.conclusionscl insulin delivery provides an effective means to reduce the risk of nh while increasing the percentage of time spent in target range , regardless of activity level in the mid - afternoon .
these data suggest that cl control could be of benefit to patients with type 1 diabetes even if it is limited to the overnight period . |
PubmedSumm118748 | ***TASK***
the task is to summarize an input biomedical literature in six sentences
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the input is a biomedical literature
***OUTPUT***
the output is the summary of an input biomedical literature in six sentences
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***EXAMPLES***
Input: arterial structure and function can now be simple and noninvasively assessed by different accurate methods , which have been extensively used in patients with cardiovascular risk factors . in this context , celermajer et al .
's technique , commonly known as flow - mediated dilation ( fmd ) , which utilizes the vasoreactivity test ( vrt ) , has stood the test of time and remains the most popular method to assess endothelial function [ 1 , 2 ] .
the vrt consists in positioning a pneumatic cuff around the forearm and provoking an arterial occlusion for five minutes ( i.e. , transient ischemia ) .
this maneuver elicits an increase in blood flow in the brachial artery once the cuff is deflated ( i.e. , reactive hyperemia , rh ) , which subsequently stimulates endothelium to release several vasoactive biochemical factors ( i.e. , nitric oxide ) .
finally , locally produced factors result in a dilation of the brachial artery ( measured by b - mode ultrasound ) and a reduction in arterial stiffness ( changes in pulse wave velocity [ pwv ] assessed by mechanotransducers ) .
the vrt has also been also applied in healthy pregnancy and in pregnancy - related diseases [ 4 , 5 ] . independently of the setting
, the magnitude of the arterial dilation is used as an indicator of endothelial function and healthy pregnant women show an enhanced vascular response evaluated by this method compared with healthy nonpregnant women [ 6 , 7 ] . however , whereas fmd provides information about the recruitability of endothelial function ( i.e. , its responsiveness to a specific stimulus ) , it does not provide information concerning basal / tonic endothelial function ( i.e. , release of endothelial autacoids before fmd measures are initiated ) . in this context , gori et al .
described a novel index for assessing the response of the artery to low flow , which utilizes data obtained from the cuff occlusion period of an fmd scan .
synonymous to fmd , the vasoconstriction observed under conditions of reduced blood flow has been named low - flow - mediated vasoconstriction ( l - fmc ) .
inclusion of l - fmc data to traditional measurement of fmd could provide additional and/or complementary information , which , they propose , may improve the detection of patients with cardiovascular disease and profile the vascular response to exercise among healthy volunteers .
whether healthy pregnancy is associated with changes in l - fmc remains to be established . in this context , it is also unknown if the integration of l - fmc into traditional fmd studies will be able to provide additional / complementary information among pregnant women .
in addition , changes in carotid - to - radial pwv ( pwvcr ) due to the same maneuver have been proposed as an alternative tool for the evaluation of recruitable endothelial function [ 3 , 11 ] .
pwv is recognized as the gold standard parameter for the evaluation of regional arterial stiffness and has had a wide biomedical application [ 12 , 13 ] .
a reduction in pwvcr values has been reported in response to vrt in healthy young adults whereas a blunted reduction has been reported in pathophysiological circumstances , such as hypertension and congestive heart failure .
a preliminary report suggested that changes in pwvcr due to vrt offer additional information of endothelial dynamics and thus could have a potential role in the assessment of endothelial function during pregnancy with a potential clinical application in predicting pregnancy - induced hypertension and preeclampsia .
finally , there is still a lack of knowledge about the expected changes for several structural and functional parameters widely used in noninvasive arterial studies . in this regard ,
if pregnancy is associated with changes in central aortic pressure , wave reflections levels and/or elastic and muscular arteries stiffness remains to be determined .
changes in arterial structure and function of both maternal muscular and elastic arteries could be of value in accommodating pregnancy - induced increasing cardiac output and blood volume for a correct maternal - fetal hemodynamic interaction [ 16 , 17 ] .
therefore , we here hypothesize that normal pregnancy , in contraposition to the nonpregnant status and particularly during the third trimester stage in which profound cardiovascular changes are expected , will evidence notable vascular adaptations ( i.e. , reduction in wave reflections levels and arterial stiffness ) , features capable of being assessed and quantified by using promising and complementary noninvasive arterial parameters . in this context
, the work aims were firstly to determine and analyze basal and recruitable endothelial function through the measurement of brachial artery fmd and l - fmc and pwvcr rh - related changes in a group of healthy nonpregnant and pregnant women and , secondly , to determine noninvasively central and peripheral arterial parameters , by using validated and gold standard techniques .
this was an analytic observational case - control study involving 11 healthy pregnant ( hp ) and 22 healthy nonpregnant women ( np ) .
the hp women were recruited from the routine antenatal clinic where they were asked and agreed to participate in the study ( convenience sampling ) .
np group was obtained from our database ( cuiidarte project and centre , republic university ) once hp women were matched based on age , height , and cardiovascular risk factors [ 1820 ] .
baseline demographic and anthropometric data were obtained by an obstetrician / physician during a clinical interview and exam , and laboratory samples were extracted prior to the examination .
they were all healthy ( with the exception of dyslipidemia in some of them ) and without family history of premature cardiovascular disease .
exclusion criteria for hp and np included previous history of pregnancy - induced hypertension ( including preeclampsia ) , gestational diabetes , or current chronic hypertension and/or diabetes mellitus .
significant unexplained proteinuria ( > 300 mg total protein in a 24 h urine collection ) developing in obstetric controls was also an exclusion criterion for hp .
the definitions for pathologies used for exclusion criteria took into account the one recommended by the national institute for health and clinical excellence guidelines [ 21 , 22 ] .
participants were asked to abstain from physical activity , tobacco products , and vitamin supplementation for at least 4 hours prior to the examination .
the study protocol was approved by the ethics research committee of the republic university ( uruguay ) and all participants gave written informed consent .
subjects were instructed to lie in a left lateral position ( particularly for hp , to avoid vena cava compression by the uterus ) in a temperature - controlled ( 2123c ) room , for at least 15 minutes , in order to establish stable hemodynamic conditions . heart rate ( hr ) and right brachial ( peripheral ) systolic and diastolic blood pressure ( psbp and pdbp , resp . )
were measured using an oscillometric device ( omron hem-433int oscillometric system ; omron healthcare inc . ,
mean blood pressure ( mbp ) was determined using classic empirical formula currently used at the peripheral level as pdbp plus one - third times of peripheral pulse pressure ( ppp = psbp pdbp ) .
the carotid - femoral pulse - wave velocity ( pwvcf ) was measured to analyze aortic regional stiffness .
to this end , carotid and femoral artery waveforms were consecutively obtained with a high - fidelity applanation tonometer from the carotid and femoral regions simultaneously with continuous ecg monitoring ( sphygmocor 7.01 , atcor medical , sydney , australia ) ( figure 1 ) .
then , carotid - femoral propagation time ( t3 ) was determined by subtracting the time delay between the peak of r wave of the ecg recording to femoral foot of the pressure waveform ( t2 ) of the corresponding cardiac cycle and the time delay between the peak of r wave to carotid foot of the pressure waveform ( t1 ) .
the algorithm utilized to detect the so - called foot of the wave was the intersecting tangents , explained elsewhere .
straight distance between the recording sites ( carotid - to - femoral distance [ c - f x ] ) was then carefully measured using tape on the body surface to reduce the influence of altered body contour in pregnancy .
finally , pwvcf was automatically calculated as the quotient between c - f x and t3 ( figure 1 ) .
the reported value of pwvcf for a subject was always the average of at least eight consecutive beats .
pulse wave analysis ( pwa ) was used to assess central hemodynamics as well as systemic arterial stiffness and wave reflections . for this porpoise ,
mean radial artery waveform was obtained ( through the acquisition of many cycles ) with the applanation tonometer from the wrist , and a corresponding mean ascending aortic pressure waveform was generated with a validated generalized transfer function using the same mentioned customized software ( sphygmocor 7.01 , atcor medical , sydney , australia ) .
the radial pulse waveform was then calibrated using the diastolic and mean arterial pressure obtained at the brachial artery .
central systolic , diastolic , and pulse pressure ( csbp , cdbp , and cpp , resp . ) , heart rate corrected central augmentation index ( aix@75 , adjusted to a rate of 75 beats / minute ) , and amplification ratio ( ppp / cpp ) were determined with the integrated software .
ultrasound assessment of carotid arteries was based on the techniques and recommendations described in international consensus .
high - resolution b - mode ultrasound images of both ( right and left ) common carotid arteries ( cca ) were obtained using a linear - array transducer connected to a portable ultrasound system ( probe l38e , 510 mhz , sonosite , micromaxx , sonosite inc .
, 21919 30th drive se , bothell , wa 98021 , usa ) . measurements ( still images and video clips / cine loops ) were digitally stored for offline analysis ( figure 1 ) . near and far walls were analyzed and images were obtained from anterior , lateral , and posterior angles . at first ,
a carotid plaque screening was performed , for which the definition used was a focal wall thickening at least 50% greater than that of the surrounding vessel , a thickening that protrudes into the lumen 0.5 mm or as a region with carotid intima - media thickness ( cimt ) greater than 1.5 mm .
then , longitudinal views of the ccas were acquired and a video ( cine loop ) of at least 30 seconds was recorded and stored .
the cimt and beat - to - beat diameter waveforms were obtained and analyzed offline using a step - by - step border detection algorithm ( based in changes in acoustic impedance [ z ] ) , applied to each digitized image ( hemodyn-4 m software , buenos aires , argentina ) .
a region 1.0 cm proximal to the carotid bulb was identified , and the far wall cimt was determined as the distance between the lumen - intima and the media - adventitia interfaces ( figure 1 ) .
the software performs multiple automated or semiautomated measurements along the centimeter and averages them , increasing the accuracy of the measures .
the instantaneous mean diameter ( from the leading edge of the near wall intima - media interface to the intima - media interface of the far wall ) waveform was obtained during pulsation in order to obtain diastolic and systolic diameter .
then , the pressure strain or peterson 's elastic modulus ( ep ) was calculated relating these measures with central blood pressure as follows : ( 1)ep = csbpcdbpsddd / dd , where csbp , cdbp , sd , and dd are central systolic and diastolic blood pressure and carotid systolic and diastolic diameter , respectively ( figure 1 ) .
ep measures the ability of the arteries to change its dimensions in response to the pulse pressure caused by cardiac pulsatile ejection ( pressure change required for ( theoretic ) 100% increase in diameter ) [ 12 , 26 , 27 ] .
once baseline noninvasive arterial evaluation was carried out , we utilized the theoretical basis , general protocol , and methodological aspects of the vrt recommended by the guidelines for the ultrasound assessment of endothelial - dependent flow - mediated vasodilation of the brachial artery [ 2 , 28 ] .
for this purpose , participants were submitted to five minutes of ischemia by occluding left radial and cubital arteries using a pneumatic cuff placed around the left forearm ( just below the elbow to at least 50 mm hg above psbp ) and several parameters of vascular reactivity were measured before , during , and after ischemia ( figure 1 ) .
the parameters used for the evaluation of endothelial function are listed below . taking into account
recruitability and simultaneously pwvcr measurement ( see later ) , left brachial artery was visualized longitudinally above the antecubital crease using the same high resolution b - mode ultrasound device mentioned earlier ( sonosite ; micromaxx ; usa ) ( figure 1 ) .
similarly , video sequences were recorded at rest ( 1 minute ) , during forearm occlusion ( 5 minutes ) , and after cuff deflation ( 4 minutes ) . subsequently and similarly to the processing of carotid images , recordings were analyzed offline using same automated step - by - step algorithm applied to each digitalized image that allows for the brachial diameter waveform obtainment and l - fmc and fmd calculation .
l - fmc was quantified as the percentage of change in brachial artery diastolic diameter ( dd ) , considering the basal levels and the dd before cuff deflation:(2)l - fmc%=ddbefore cuff deflationddbaselineddbaseline100 .
fmd was quantified as the percentage of change in brachial dd , considering the basal levels and the maximal diastolic diameter after cuff deflation:(3)fmd%=ddafter cuff deflationddbaselineddbaseline100 .
in addition , doppler signals were performed to acquire blood flow velocity in baseline conditions and at specific moments during the rh period .
doppler signals were used to obtain the brachial shear rate ( sr ) and its percentage of change , relating mean blood flow velocity ( vm [ cm / s ] ) to brachial mean diameter ( dm ) according to the following equations:(4)sr = vmdm , sr%=srafter cuff deflationsrbaselinesrbaseline100 .
sr is an estimate of shear stress without accounting for blood viscosity and was obtained for the characterization of the endothelial stimulus .
noninvasively , carotid and radial pressure waveforms were simultaneously obtained using strain gauge mechanotransducers ( motorola mpx 2050 , motorola inc .
, corporate 1303 e. algonquin road , schaumburg , illinois 60196 , usa ) by placing them on the skin over the carotid and radial sites ( left hemibody ) .
pwvcr was determined taking into account the given distance between these arterial sites ( c - r x ) and the time delay ( t ) between the carotid and radial waveforms onset ( figure 1 ) .
the algorithm used for the detection of the foot waves was described and explained in previous work .
although a four - minute recording postcuff release was obtained , one - minute postischemia was the specific moment where the analysis was especially taken , according to previous reports [ 14 , 31 , 32 ] .
pwvcr levels corresponding to baseline and to post - ischemia period were determined by averaging eight consecutive beats . after that , percent of change of pwvcr ( with respect to basal levels ) was quantified as follows:(5)pwvcr%=pwvcrafter cuff deflationpwvcrbaselinepwvcrbaseline100 .
the statistical analyses were performed using the statistical package for social sciences ( version 19.0 ) .
all data were expressed as mean value ( mv ) standard deviation ( sd ) and
comparisons between pregnant and non - pregnant women were performed using two - tailed unpaired student t - test .
differences in prevalence were analyzed using test with or without yates 's correction if appropriate .
differences in percentage of change of variables determined before and after the vrt ( arterial diameter , pwv and shear rate ) were evaluated using two - tailed paired student t - test .
recordings were successfully obtained from all women and all studies were included in the analysis .
the mean duration of the studies was one hour approximately and they were all well tolerated ( without symptoms and/or complications ) .
demographic , anthropometric , and clinical data are shown in table 1 . as was mentioned above , age , height , and cardiovascular risk factors
body mass index was significantly higher in hp compared with np ( p < 0.05 ) .
in addition , baseline pdbp and mbp levels were significantly higher in np in comparison with hp ( p < 0.05 ) .
however , in addition to differences in cdbp , significantly higher values in csbp were evidenced in np women .
mean aix@75 was higher in np with respect to hp ( 18.8 10.1% versus 8.9 8.6% ; resp . ; p = 0.019 ) , whereas amplification ratio was significantly reduced ( table 2 ) .
when analyzing geometrical and biomechanical characteristics of muscular peripheral arteries important differences were found between groups . in concrete , basal brachial sd and dd were significantly increased in hp versus np ( p < 0.001 ) and pwvcr values were higher in np compared with hp ( p = 0.003 ) .
elastic arteries such as aorta and ccas were also analyzed by both regional and local arterial stiffness parameters ( table 2 ) .
meaningfully differences in stiffness were only evidenced in regional stiffness ( pwvcf ) , which was significantly reduced in hp .
values of local stiffness ( ep ) of both right and left cca did not reach statistical differences among groups , despite the lower mean values that were found in hp .
structural differences were only noticed on the right cca , where cimt was significantly reduced in hp with respect to np women ( p = 0.044 ) .
taking into account the vrt , all groups evoked endothelial stimulus ( reactive hyperemia ) evaluated by changes in sr before and after cuff deflation ( p < 0.001 ) ( table 3 ) .
pregnancy was associated with increased baseline sr values in comparison with np controls ( 66.2 24.4 s versus 110.8 40.1 s ; p < 0.001 ) . nevertheless ,
after cuff deflation , peak sr and sr% were not different between groups ( p = 0.079 and p = 0.525 , resp . ) , ensuring a similar hyperemic stimulus ( table 3 ) .
as was expected , no significant changes were found in heart rate or blood pressure intra- and intergroup before and after the cuff deflation ( data not shown ) . regarding the fmd
, both groups showed dilatation of the brachial artery with respect to basal state , but as was expected , hp women showed quantitatively the highest fmd response ( 9.6 3.4% versus 7.1 2.3% ; p < 0.05 ) ( table 3 ) , despite the higher basal brachial artery diameter existing in hp ( table 2 ) .
one minute after cuff deflation , pwvcr significantly decreased in both hp ( 6.8 1.4 to 5.8 0.9 m / s ; p = 0.005 ) and np ( 8.4 1.1 to 7.4 0.9 m / s ; p < 0.001 ) .
the mean absolute change of the study groups was similar ; however pwvcr response in % differed comparing hp women with np women ( 14.0% versus 8.5% ; p < 0.05 ) ( table 3 ) .
l - fmc of the brachial artery occurred in both groups independently of the physiological status ( p < 0.001 ) .
however , even though maximal vasoconstriction of the brachial artery ( negative values ) was observed in hp women ( 7.0 4.7% ; p < 0.001 ) in comparison to np ( 5.7 2.4% ; p < 0.001 ) , the magnitude of the reduction of arterial diameters was not statistically different between the groups ( table 3 ) . finally , there were no significant correlations between endothelial function parameters ( fmd , l - fmc , or pwvcr% ) and aix@75 , pwvcf , or central blood pressure ( data not shown ) . however , fmd correlated with l - fmc ( r = 0.54 , p = 0.038 ) and pwvcr% ( r = 0.419 , p = 0.037 ) , whereas no significant correlation was evidenced between pwvcr% and l - fmc ( r = 0.30 , p = 0.198 ) .
a positive correlation between l - fmc ( negative number ) and basal sr ( positive number ) was found across the whole studied population ( r = 0.587 , p = 0.017 ) .
the present study is , to our knowledge , the first one to determine and assess simultaneously , in a group of healthy pregnant women , the endothelial function by using three different but complementary methods in conjunction with the determination of central and peripheral structural and functional arterial validated parameters .
these approaches allow us to conclude that , with respect to nonpregnant women matched by age , anthropometric features and cardiovascular risk factors , pregnant women showed ( 1 ) reduced aortic and upper limb
arterial stiffness levels , in coherence with the higher basal brachial artery diameters that were found in this group ; ( 2 ) reduced central ( aortic ) , but not peripheral , systolic blood pressure , determined by a reduced contribution of reflected waves to central aortic pressure waveform ( lower aix@75 ) ; ( 3 ) an enhanced recruitable ( fmd ) , but not resting ( l - fmc ) , endothelial function , despite higher basal brachial diameters . regarding the hemodynamic parameters
, we found that hp women showed , in comparison to controls , increased hr and reduced pdbp and mbp in basal state .
these findings are in consonance with an expected pregnancy - induced decrease in peripheral vascular resistance and increased cardiac output at rest . however , pregnancy - related changes were also notable when central hemodynamics is analyzed .
central ( aortic ) systolic blood pressure and pwvcf ( aortic stiffness ) were lower in hp comparing to controls , independently of brachial systolic blood pressure levels .
in addition , aix@75 , a composite parameter of systemic arterial stiffness and wave reflection amplitude , was different between hp and np .
this suggests that healthy pregnancy is associated with reduced wave reflection contribution to the central aortic pressure waveform and central arterial ( aortic ) stiffness .
however , changes in cca stiffness ( ep ) related with pregnancy were not statistically significant , despite lower mean levels in hp .
report , since these authors evidenced that carotid arterial distensibility ( inverse of ep ) decreased towards the end of the pregnancy reaching the lowest values in the third trimester
. nevertheless , taking our results together , we evidenced that healthy pregnancy is associated with reduced aortic stiffness , central systolic pressure , and wave reflections . among the methods that allow for measurement of endothelial function in the clinical setting , fmd has rapidly gained popularity because of its simplicity , reproducibility , and noninvasiveness [ 2 , 28 ] . however , as was mentioned earlier , one important limitation of fmd is that it only provides information about the recruitability of endothelial function ( i.e. , its responsiveness to a specific stimulus ) and not about resting endothelial function ( i.e. , release of endothelial autacoids before fmd measures are initiated ) .
we here analyze , in healthy pregnant women , both types of functional aspects of endothelial function , endothelial recruitability through fmd and pwvcr changes and resting endothelial tone through l - fmc . as it was expected , the magnitude of fmd observed in hp in response to vrt surpassed that observed in np .
this finding , which is similar to that described in previous reports , is in coherence with an enhanced endothelial function assessed by this method [ 6 , 7 ] . on another side , when analyzing changes in arterial stiffness due to vrt , even though both groups showed a reduction in pwvcr values , hp showed the major decrease ( p < 0.05 ) .
it is noteworthy that both groups showed a similar endothelial stimulus , since peak sr and sr% were similar between them .
in addition , even though starting ( basal ) levels of brachial diameter and pwvcr ( basal state ) in hp were higher and lower , respectively , these values were not correlated with the vascular response ( i.e. , fmd and pwvcr% ) .
when examining the relationship between fmd and pwvcr the analysis should take into account the moens and korteweg equation .
in that sense , pwv is determined by both arterial diameter and the elastic modulus , among other factors . in a previous study , we evidenced in healthy subjects that changes in pwvcr due to the vrt may be also provoked by a smooth muscle relaxation .
if there were a right shift in the brachial pressure - volume loop , post - cuff deflation , in addition to a slope decrease due to smooth muscle relaxation , the global response might suit our results ( as pwvcr changes were even higher than those only expected by changes in vmf ) . in light of our results
, we hypothesize that besides an enhanced vasodilatory response , smooth muscle relaxation could be pronounced in healthy pregnancy . taking into account
resting endothelial tone , our results show that , during the cuff inflation , l - fmc occurred in the brachial artery independently of the physiological status .
although l - fmc was firstly described at the radial artery as a specific phenomenon , in the 90 's it had been already reported in the brachial artery in response to the cuff occlusion in subjects with hypercholesterolemia .
evidenced that this specific phenomenon also occurs in healthy subjects at the brachial artery and it can be measured reliably .
studies agree that vasoconstriction of the radial artery occurs during the cuff inflation in nonpregnant women , although the mechanisms involved remain not completely understood [ 9 , 35 , 36 ] .
l - fmc of the brachial artery has been controversial and several studies demonstrated conflicting results [ 3335 , 37 , 38 ] .
did not evidence l - fmc in the brachial artery in pregnant women , in contraposition with our results .
differences in cardiovascular profile , technical aspects , methodological issues , and/or interobserver variability could explain the widely variable results , as it occurs with fmd measurements [ 3941 ] .
for example , we here measure l - fmc of the brachial artery in a regimen of low but not zero blood flow ( as it occurs in the radial artery ) in a level that is upstream of the occlusion site .
therefore , the magnitude of reduced blood flow in the brachial artery and its relationship with the basal levels ( endothelial negative stimulus for vasoconstriction ) should surely yield different brachial responses .
nevertheless , our results indicate that the more the basal blood flow ( or sr ) , the more the vasoconstriction of the brachial artery provoked by the occlusion of the pneumatic cuff . even though we did not measure the residual brachial blood flow during the cuff occlusion , it is expected that the absolute change in brachial blood flow may be of greater amount with the same occlusion protocol , if the starting point of blood flow in basal conditions is increased ( i.e. , increased negative
we found a significant correlation between fmd and l - fmc , fmd and pwvcr% , but not between l - fmc and pwvcr% .
our results indicate that brachial artery responses to inflation and deflation of the cuff related with endothelial dynamics could share some vascular mechanism
. however , there are confusing results around the fmd and l - fmc correlation , with variable results depending on the analyzed artery ( brachial versus radial ) and type of physiological or pathophysiological circumstance [ 810 , 34 ] .
although both l - fmc and fmd are an expression of the vascular reactivity in response to changes in blood flow , their relationship is neither conceptually simple nor mathematically linear .
nevertheless , it is reasonable to think that the same vasodilatatory mechanisms ( i.e. , nitric oxide ) involved in response to increased blood flow ( shear stress ) will diminish ( with the consequent vasoconstriction ) when the stimulus for its production is reduced / abolish .
the important additional information brought by the introduction of changes in pwvcr and l - fmc , together with the information of central and peripheral hemodynamics , is that these variables provide information concerning different aspects of vascular reactivity and endothelial function , therefore complementing ( and not overlapping ) the information provided by fmd .
an enhanced response and/or increased vasodilator reserve to changes in blood flow in a concrete vascular ledge ( i.e. , brachial artery ) implicates an elevated capability of the arterial system to accomplish an appropriate vascular adjustment against hemodynamic changes in the long term ( fetal growth ) and even in the short term ( exercise , change of position , etc . ) .
in addition , these could be associated with cardiovascular benefits reported by other authors like reduced left ventricle afterload and improve diastolic function and reduced myocardial oxygen demand in the maternal circulation [ 4244 ] .
previous results of our group suggested that pregnancy - induced hypertension ( i.e. , preeclampsia - eclampsia syndrome ) could be associated with increased central aortic pressure , elastic arteries stiffness , and wave reflections , in conjunction with both resting and recruitable endothelial dysfunctions .
these arterial disturbances would not only blunt the mentioned hemodynamic benefits of the pregnancy physiological condition but also add extra load to the maternal circulation in the context of increased cardiac output and fetal requirements .
however , although this comprehensive arterial assessment would improve our understanding of the haemodynamics of both healthy pregnancy and pregnancy - related diseases , the inclusion of this information together with the recognized validated clinical , obstetric , and laboratory variables remains to be addressed during the first trimester of pregnancy , since at this time they could have an additional / complementary value in the prediction of preeclampsia [ 46 , 47 ] . in this small study , that addresses the feasibility of measuring these parameters simultaneously , simply , and noninvasively , we found encouraging results that , we believe , warrant further investigation .
however , our findings were statistically significant and , by definition , this indicates that the study was adequately statistically powered .
our technical approaches including the use of both multiple types of automated and semiautomated edge - detection / point software in ultrasound image and pressure wave assessment are largely operator independent and also empower our findings .
given the means of the different variables and sds observed in previous works and in the present sample , twenty - eight subjects ( n = 28 ) of the total sample size ( the sum of the sizes of comparison groups ) would be required to detect a statistically significant effect of the pregnancy status with at least 80% of power . secondly , even groups were properly matched , women with dyslipidemia were included in the analysis , and this could have an impact in our results , being a limitation of the healthy groups .
this vascular approach may provide a more comprehensive assessment of vascular state and endothelial function in normal pregnancy .
future studies will have to determine if accounting of this information , particularly during the early stages of pregnancy ( i.e. , first trimester ) , in conjunction with recognized important clinical , obstetric , laboratory variables , will be able to improve early detection of pathophysiological circumstances like pregnancy - induced hypertension .
with respect to nonpregnant women matched by age , anthropometric features and cardiovascular risk factors , pregnant women showed ( 1 ) reduced aortic and upper limb
arterial stiffness levels , in coherence with the higher basal brachial artery diameters that were found in this group ; ( 2 ) reduced central ( aortic ) , but not peripheral , systolic blood pressure , determined by a reduced contribution of reflected waves to central aortic pressure waveform ; and ( 3 ) an enhanced recruitable , but not resting , endothelial function , despite higher basal brachial diameters .
Output:
| introduction .
flow - mediated dilation ( fmd ) , low flow - mediated constriction ( l - fmc ) , and reactive hyperemia - related changes in carotid - to - radial pulse wave velocity ( pwvcr% ) could offer complementary information about both
recruitability and resting endothelial function ( ef ) . carotid - to - femoral pulse wave velocity ( pwvcf ) and pulse wave analysis - derived parameters ( i.e. , aix@75 ) are the gold standard methods for noninvasive evaluation of aortic stiffness and central hemodynamics . if healthy pregnancy is associated with both changes in resting and recruitable ef , as well as in several arterial parameters , it remains unknown and/or controversial .
objectives .
to simultaneously and noninvasively assess in healthy pregnant ( hp ) and nonpregnant ( np ) women central parameters in conjunction with basal and recruitable ef , employing new complementary approaches .
methods .
hp ( n = 11 , 34.2 3.3 weeks of gestation ) and age- and cardiovascular risk factors - matched np ( n = 22 ) were included .
aortic blood pressure ( bp ) , aix@75 , pwvcf , common carotid stiffness , and intima - media thickness , as well as fmd , l - fmc , and pwvcr % , were measured .
results .
aortic bp , stiffness , and aix@75 were reduced in hp .
pwvcr% and fmd were enhanced in hp in comparison to np .
no differences were found in l - fmc between groups . conclusion .
hp is associated with reduced aortic stiffness , central bp , wave reflections , and enhanced recruitable , but not resting , ef . |
PubmedSumm118749 | ***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 associated with high morbidity and mortality especially in children under five years of age . the economic loss due to malaria infection is huge in malaria endemic regions .
it has been estimated that , in some countries of sub - saharan africa ( ssa ) , up to 10% of monthly income could be spent on procuring a complete dose of act for a child [ 1 , 2 ] .
the epidemic of malaria has been fuelled by widespread resistance to cheap antimalarial drugs like chloroquine .
thus , there was an urgent need to shift from monotherapy to combination therapy in order to prevent further development of resistance . in 2001 , the world health organization ( who ) recommended artemisinin - based combination therapy ( act ) as the first line therapy for uncomplicated malaria .
since then adoption of act in malaria endemic countries especially in ssa has been slow due to the lack of understanding of the concept of act , its fundamental principles , and its high cost .
other problems relate to the nonavailability of appropriate paediatric formulations and the erratic supply of acts in endemic areas .
adoption of act as the first line treatment for uncomplicated malaria could have positive impact on individuals , their families , and the community at large by reducing incidence of complications , preventing development of multidrug resistant malaria species and reducing the socioeconomic burden of malaria infection .
in addition act reduces morbidity and mortality from malaria indirectly by preventing progression of uncomplicated malaria to severe malaria .
acts not only are good in treatment of malaria but also serve as tools for prevention and control of malaria due to their ability to reduce the infectivity of mosquitoes especially in areas of low or moderate malaria transmission .
several act combinations available include artemether - lumefantrine ( al ) , artesunate - amodiaquine ( as / aq ) , artesunate - mefloquine ( as / mq ) , artesunate - chlorproguanil - dapsone ( as / cd ) , artesunate - sulphadoxine - pyrimethamine ( as / sp ) , dihydroartemisinin - piperaquine ( da / pq ) , artesunate - piperazine ( as / pz ) , and artesunate - atovaquone - proguanil ( a / ap ) . out of these act combinations who recommended al , as / mq , as / aq , and as / sp .
several countries have now adopted acts as the first line agents for uncomplicated malaria . however , a major challenge with act is that because of the rapid response and resolution of symptoms patients or caregivers of children tend to terminate treatment prematurely keeping the remaining tablets for future malaria episodes [ 8 , 9 ] .
studies conducted across the world have reported varying levels of adherence to act both in the public and retail sectors .
moreover , two recently published reviews also noted this wide variation in adherence to act [ 10 , 11 ] .
this meta - analysis was therefore conducted to derive pooled estimates of prevalence and predictors of adherence to acts since adherence has been shown to be a key challenge in the implementation and adoption of act .
peer - reviewed articles published in english language were searched for electronically in google scholar , medline , embase , ajol , web of science , cochrane database , and other relevant web sites .
medical subject heading ( mesh ) terms applied in different combinations include malaria , adherence , non adherence , predictors , risk factors , artemisinin , antimalarial , and treatment .
all studies that satisfied the following criteria were included.reported prevalence and/or predictors of adherence to act given for the treatment of uncomplicated malaria.reported method of assessing adherence . reported prevalence and/or predictors of adherence to act given for the treatment of uncomplicated malaria . reported method of assessing adherence .
this meta - analysis was conducted and reported according to the guidelines of preferred reporting items for systematic reviews and meta - analysis ( prisma ) and meta - analysis of observational studies in epidemiology
for each of the included studies we recorded the prevalence of adherence to act and the 95% confidence interval ( ci ) , the standard error , the log of the prevalence , the odds ratio of adherence , and the log of odds ratio .
dersimonian and laird meta - analyses were performed on the prevalence and odds ratio of adherence to act .
the level of statistical heterogeneity was used to select an appropriate model for the meta - analysis .
specifically , where we encountered significant heterogeneity ( i statistics > 50% ) , a random effects model ( rem ) is applied whereas if heterogeneity is not significant we apply a fixed effects model ( fem ) .
publication bias was assessed with begg 's and egger 's tests [ 17 , 18 ] . because these tests could be inconsistent and
sometimes a funnel plot could be misleading , we considered publication bias to be present if both tests were able to detect it [ 19 , 20 ]
. sensitivity analysis was done to examine if any of the studies exerts profound influence on meta - analysis estimates .
stata version 12 ( stata corp . , college station , tx , usa ) was used for data analysis . as shown in figure 1 , thirty - one studies ( twenty - five main studies and six substudies ) [ 12 , 2245 ] met the inclusion criteria and their characteristics are shown in table 1 .
twenty - two of the studies ( and three substudies ) were done in the public sector where medications were given for free and dispensed by health professionals with clear instructions [ 2235 , 37 , 3945 ] .
the other six studies were done in the retail sector where patients or caregivers buy medications from drug stores or supermarkets without proper instructions on how to take them [ 12 , 36 , 38 , 40 ] .
all the studies included in the systematic review and meta - analysis had satisfactory data quality as shown in table 2 .
questions on adherence to act were responded to by adults , adolescents , and caregivers of children .
as indicated in figure 2 , using rem the pooled prevalence ( 95% ci ) of adherence to act from the twenty - five studies done in the public sector was 75.78% ( 68.08%83.49% ) .
there was publication bias indicated by significant p values in both begg 's and egger 's tests ( 0.002 and 0.012 , resp . ) .
sensitivity analysis showed that none of the studies exert profound influence on the derived estimates of adherence . from the six studies done in the retail sector the rem pooled prevalence ( 95% ci ) of adherence to act was 44.75% ( 36.90%77.43% ) .
no publication bias was detected ( begg 's test p value = 0.851 and egger 's test p value = 0.699 ) . when meta - analysis was restricted to the eighteen studies ( and two sub - studies )
[ 12 , 22 , 24 , 25 , 2831 , 3440 , 42 , 43 , 45 ] that administered al , the rem pooled prevalence of adherence ( 95% ci ) was 70.52% ( 60.82%80.22% ) .
no publication was detected ( begg 's test p value = 0.056 and egger 's test p value = 0.018 ) . from the six studies [ 22 , 23 , 26 , 27 , 38 , 44 ] that administered as - aq , the rem pooled prevalence of adherence ( 95%ci ) was 68.05% ( 50.90%85.19% ) .
no publication bias was detected ( begg 's and egger 's tests p values were 0.133 and 0.003 , resp . ) . from the 13 studies ( and 5 substudies )
[ 22 , 23 , 26 , 28 , 30 , 31 , 34 , 35 , 38 , 39 , 41 , 42 , 44 ] performed in areas with high malaria transmission intensity , the prevalence ( 95% ci ) of act adherence was 77.88% ( 69.08%86.67% ) .
there was publication bias ( begg 's and egger 's tests p values were 0.002 and 0.001 , resp . ) .
the pooled prevalence ( 95% ci ) of act adherence from the ten studies ( and one substudy ) [ 12 , 24 , 27 , 29 , 32 , 33 , 36 , 37 , 40 , 45 ] performed in areas with low to moderate malaria transmission intensity was 55.58% ( 44.23%66.94% ) with nonsignificant p values in both begg 's and egger 's tests ( 0.640 and 0.237 , resp . ) .
from the eighteen studies ( and two substudies ) [ 12 , 2225 , 2831 , 3438 , 40 , 42 , 43 , 45 ] that used twice daily act , the prevalence of adherence was 69.33% ( 59.57%79.09% ) .
there was publication bias ( begg 's test p value = 0.022 and egger 's test p value = 0.011 ) .
from the ten studies [ 22 , 26 , 27 , 32 , 33 , 38 , 41 , 42 , 44 ] that used once daily act , the prevalence of adherence was 66.01% ( 52.72%79.29% ) with no publication bias ( begg 's test p value = 0.074 and egger 's test p value = 0.001 ) .
the prevalence of adherence to act derived from the eleven studies ( and one substudy ) [ 22 , 23 , 26 , 27 , 32 , 33 , 38 , 4042 , 44 ] that administered copackaged act was 66.53% ( 54.23%78.83% ) . there was no publication bias ( begg 's test p value = 0.075 and egger 's test p value = 0.008 ) .
the prevalence of adherence from the nineteen studies ( and two substudies ) [ 12 , 22 , 24 , 25 , 2831 , 3440 , 4245 ] that administered fixed drug combination act was 70.11% ( 60.88%79.34% ) .
there was no publication bias ( begg 's test p value = 0.070 and egger 's test p value = 0.016 ) . in metaregression analysis
the prevalence of adherence to act significantly decreases with increasing year of publication as shown in figure 3 ( p = 0.046 , 95% ci = 4.223 to 0.036 ) . these are shown in figures 4 and 5 .
this meta - analysis found significantly higher level of adherence to act in the public sector as compared to retail sector ( 76% and 45% , resp . ,
this is not unexpected as the two sectors differ in functions , structure , and quality of services offered . in the public sectors ,
acts are usually given for free and health professionals offer clear instructions on how to take medications .
in this meta - analysis some of the included studies done in the public sector provided acts with pictorial instruction . this may enhance compliance and ingestion of correct dosages at the right time .
on the other hand the retail sector observations reflect the real life situation in most communities in malaria endemic countries where patients or caregivers of children commonly purchase acts from informal private outlets such as drug stores , pharmacies , and supermarkets .
these private outlets may or may not be licensed to sell drugs and about 80% of malaria episodes commonly receive antimalarial therapy in these settings .
diagnoses of malaria in these settings most of the time are presumptive and drugs with questionable potency are dispensed without clear instructions . in drug shops , presumptive treatment of malaria is one of the factors identified to be responsible for the inappropriate act treatment of most cases .
the reported efficacy of acts from clinical trials may be difficult to maintain in communities with poor act adherence , inappropriate drug policies , substandard drugs , and poor supervision and monitoring by drug regulatory agencies .
this meta - analysis found poor adherence in children less than five years of age which may be related to the lack of appropriate dose formulations for this vulnerable age group .
the probability of developing drug resistant malaria species is higher in children less than five years of age than in adults because of higher parasite biomass in children . in places of low intensity malaria transmission ,
poorly or incompletely treated malaria infections in the presence of a high parasite biomass could promote development of de novo resistance to antimalarial drugs . due to
the high cost of act , parents or caregivers of children may favour traditional medication over act .
moreover , coadministration of act with traditional medication could lead to treatment interruption , subtherapeutic drug concentration , poor parasitological and clinical response , and nonadherence .
findings from this meta - analysis indicate that lower socioeconomic status ( ses ) predicts poor adherence to act .
children from poorer families may not receive optimum treatment and care during episodes of malaria infection as compared to children from richer families .
the role of ses in act adherence is multidimensional because some of the factors associated with good adherence to act from this meta - analysis may be directly or indirectly related to ses .
other factors we found to be associated with good adherence to act include instructing patients or caregivers to ingest act with fatty food , receiving the exact number of pills required for full treatment , and knowledge of correct act dose .
these dispensing - related factors could positively influence adherence where the pharmacists or healthcare workers routinely practice them while dispensing act .
proper communication skills could promote adherence to act as we observed in this meta - analysis .
informing caregivers or parents that their child had malaria and availability of visual aid to enhance understanding of dosing instructions were associated with good adherence .
severity of malaria at presentation may determine the level of adherence as we found that patients with jaundice and high body temperature at presentation had good adherence to act .
patients , parents , or caregivers of children may perceive these symptoms as serious thereby promoting adherence with treatment instructions .
the cost of act is up to 20 times that of previous conventional drugs such as chloroquine and sulphadoxine - pyrimethamine used for the treatment of uncomplicated malaria . the high cost of act together with the cost of effecting policy change may have contributed to the delay in adopting act as the first line choice for uncomplicated malaria in resource poor settings .
concern over the safety of acts had also contributed to delay in adopting it as first line therapy .
neurotoxicity manifesting as hearing loss has been reported with use of coartemether to treat uncomplicated malaria .
we observed fairly similar levels of adherence to al and as / aq ( 71% and 80% , resp .
it has been reported that adherence to antimalarial agents is inversely proportional to length of therapy and frequency of taking dosages .
the complete treatment of uncomplicated malaria requires a patient to take 6 doses of al as compared to 3 doses for other act - based combinations . despite the increased dosages of al over as / aq
, we did not observe a statistically significant difference in adherence to these antimalarial agents .
further , fairly similar levels of adherence were observed between single and twice daily acts in this meta - analysis ( 66% and 69% , resp .
adherence to copackaged acts was also fairly similar to that of fixed drug combination acts ( 67% and 70% , resp . ,
however , it is worthy to note that the accuracy of adherence to copackaged acts is limited by publication bias .
further studies are needed to assess the influence of dosing regimen complexity , copackaging , and fixed drug combination on adherence to act .
it was observed in this study that poor adherence to act was mainly in the last two doses at the end of treatment [ 25 , 28 , 35 , 45 ] .
this may be related to the rapid resolution of symptoms after the first few doses which caregivers or patients wrongly interpret as cure .
for economic reasons some patients may be tempted to keep remaining tablets for anticipated episodes of malaria .
substandard antimalarial drugs pose a major threat to global efforts to combat malaria . a survey of drugs conducted in 21 countries in ssa found substantial proportion of drugs that failed chemical and packaging analysis while others were falsified .
poor quality acts in addition to poor adherence could amplify the rate at which multidrug resistant malaria strains develop .
resistance to artemisinin has already been reported [ 54 , 55 ] and efforts to curtail this resistance should consider level of poor adherence to act in the retail sector , public sector , and areas with low to moderate malaria transmission intensity .
it was observed in this meta - analysis that adherence to act in areas with high malaria transmission intensity was significantly higher than adherence in areas with low to moderate transmission intensity ( 78% and 56% , resp . ,
this poor adherence to act in areas with low to moderate malaria transmission intensity is a major concern because drug resistant plasmodium falciparum infection may spread more rapidly in this setting [ 56 , 57 ] .
self - report used to assess adherence when blister pack is not available for verification is not a good measure of adherence due to recall bias .
only one study used electronic pill - box monitoring which is a more accurate way of assessing adherence . different thresholds of adherence were used in the studies and include percentage of correctly ingested doses or number of tablets left on day three .
determination of blood concentration of drugs to confirm adherence was done only in 4 studies [ 28 , 31 , 35 , 41 ] and self - report of adherence was found to have a failure rate of 2.4% in one of the studies .
although assaying blood levels of acts could increase accuracy of defining adherence , its role in this meta - analysis may be limited by pharmacokinetic differences between children and adults .
variable blood concentrations of acts could arise from age- or weight - based dosing and ingestion of lumefantrine with fatty meal ( instruction not given in some of the studies ) .
despite these caveats , restricted analysis reduces heterogeneity and confounding thereby increasing reliability of estimates .
the strength of this meta - analysis lies in its large sample size ( 8654 subjects ) , exclusion of confounders , and unannounced home visit in most of the studies included ( see table 2 ) .
two recently conducted systematic reviews found wide variability of act adherence across different populations [ 10 , 11 ] . in these reviews
there are no pooled estimates of prevalence of adherence and this could undermine their epidemiologic significance .
however , effort was made to substantially reduce heterogeneity between studies by meta - analytically pooling estimates from fairly similar populations via restricted analysis .
currently act is the best and recommended first line therapy for uncomplicated malaria in several countries ( see table 3 ) . to maintain its long term efficacy
there is a need to train healthcare providers on appropriate dosing and dispensing of act .
the poor adherence observed in the retail sector and areas with low to moderate malaria transmission and suboptimal adherence in public sector calls for more efforts to improve adherence to act in malaria endemic countries of the world .
barriers to adherence should be addressed because nonadherence could be a platform for the development of antimalarial resistance . at community level people
training of healthcare providers and adequate supply of subsidized potent acts with clear instructions and packaging leaflets in local languages could improve adherence .
furthermore , pictorial instructions could help bridge the communication gap that may exist between health professionals and patients or caregivers .
findings from this systematic review and meta - analysis indicated that adherence to act in the retail sector and areas with low / moderate malaria transmission are poor .
healthcare providers , policy makers , and other stakeholders involved in malaria control programs should take cognisance of these findings when designing targeted interventions to improve act adherence . educational programs to increase awareness and understanding of act dosing regimen are interventions urgently needed to improve adherence to act .
patients or caregivers should be provided with an adequate explanation at the time of prescribing and/or dispensing act .
prescribers , dispensers , and vendors should , therefore , give a clear and comprehensible explanation on how to use act .
user - friendly packaging ( e.g. , blister packs ) should be used to encourage completion of the treatment course and correct dosing .
Output:
| adherence to artemisinin - based combination therapy ( act ) is not clearly defined .
this meta - analysis determines the prevalence and predictors of adherence to act .
twenty - five studies and six substudies met the inclusion criteria .
the prevalence of act adherence in the public sector was significantly higher compared to retail sector ( 76% and 45% , resp .
, p < 0.0001 )
. however , act adherence was similar across different act dosing regimens and formulations . in metaregression
analysis prevalence estimates of adherence significantly decrease with increasing year of study publication ( p = 0.046 ) .
factors found to be significant predictors of act adherence were years of education 7 { odds ratio ( or ) ( 95% ci ) = 1.63 ( 1.052.53 ) } , higher income { 2.0 ( 1.352.98 ) } , fatty food { 4.6 ( 2.498.50 ) } , exact number of pills dispensed { 4.09 ( 1.6010.7 ) } , and belief in traditional medication for malaria { 0.09 ( 0.010.78)}. the accuracy of pooled estimates could be limited by publication bias , and differing methods and thresholds of assessing adherence . to improve act adherence ,
educational programs to increase awareness and understanding of act dosing regimen are interventions urgently needed .
patients and caregivers should be provided with an adequate explanation at the time of prescribing and/or dispensing act . |
PubmedSumm118750 | ***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 peripheral nervous system ( pns ) , neuromuscular junctions contain a well - defined basal lamina composed of a highly ordered network of extracellular matrix ( ecm ) proteins such as laminins and collagens .
this structure is important for the formation and function of this synapse ( patton 2003 ) .
the lack of such an obvious organization of the ecm in the central nervous system ( cns ) has led to the misconception that the ecm does not exist in the brain .
therefore , its role in the development and the function of the cns has been largely neglected . however , many ecm proteins are indeed expressed in the nervous system ( dityatev and schachner 2006 ) . among these are the matricellular proteins which do not appear to contribute directly to the structural organization of the ecm , but rather seem to function by modulating cell - cell and cell - matrix interactions ( bornstein 2000 ) .
thrombospondin family members tsps1 - 4 , sparc and its homolog sparc - like 1 ( hevin ) and tenascin c are matricellular proteins with interesting spatial and temporal expression patterns in the cns ( adams and tucker 2000 ; lively and brown 2008a ; mendis et al . 1995 ; vincent et al . 2008 ) .
recent gene expression profiling of different cell types in the brain further showed that the messenger rnas ( mrnas ) for these matricellular proteins were mostly enriched in glia and were particularly expressed by developing astrocytes ( table 1 , ( cahoy et al . 2008 ) ) .
table 1cellular origin of matricellular protein gene expression in the developing and adult rodent brain . adapted from data published in ( cahoy et al .
2008)neuronsearly postnatal astrocytesadult astrocytescultured astrocytesoligodendrocytestsp1absentpresentabsenthighabsenttsp2absentpresentabsenthighabsenttsp3absentpresentlowhighpresenttsp4absentabsentpresentabsentabsenttn - cabsentvery highpresentpresentabsentsparcabsenthighpresentvery highlowhevin / sparc like1presentvery highvery highhighlow cellular origin of matricellular protein gene expression in the developing and adult rodent brain .
2008 ) astrocytes are the most abundant cells in the mammalian brain , however the full extent of their properties and the specific roles they play in the formation and function of the cns remains to be determined ( barres 2008 ) .
one astrocyte is estimated to contact thousands of synapses through these intricate processes ( bushong et al . 2002 ) .
this close association enables astrocytes to participate actively in synaptic signaling through release and uptake of neurotransmitters and neuroactive substances ( reviewed in ( eroglu et al .
recognition of this tight structural and functional association of astrocytes with the synaptic cleft led to the redefinition of the compartments of the synapse to include perisynaptic astrocytic process and neuronal pre and postsynaptic specializations , collectively referred to as the tripartite synapse ( araque et al .
for example , the majority of excitatory synapses in the brain form during the second and third postnatal weeks , even though the neuronal maturation and axon path - finding events are mostly completed by birth .
this 1-week delay between target innervation by neurons and the establishment of synapses correlates with the appearance and maturation of astrocytes in the brain , which suggests that astrocytes may provide instructive cues that contribute to the initiation of excitatory synapse formation ( ullian et al .
studies of the role of astrocytes in the mammalian nervous system have been a challenge since glia are crucial for the survival of neurons both in vivo and in vitro ( banker 1980 ; craig and banker 1994 ; shaham 2006 ) . as such , neuronal culture systems that are traditionally utilized to study synapse formation contain glia . to circumvent this limitation ,
meyer - franke and colleagues developed a retinal ganglion cell ( rgc ) culture system that utilizes an immunopanning strategy to purify these neurons with up to 99.9% homogeneity from rodent retina ( meyer - franke et al .
rgcs then can be cultured in a serum - free media of known composition and in the complete absence of glia making this an ideal in vitro model to study the role of astrocytes in synaptic development .
interestingly , an initial analysis of synapse formation and function in these cultures revealed that rgcs do not establish synapses in culture .
however when these cells were cultured either in the presence of astroglial feeding layers or astrocyte conditioned media ( acm ) , rgcs formed many active synapses , suggesting the presence of secreted synaptogenic signals provided by astrocytes ( pfrieger and barres 1997 ; ullian et al .
to identify the synaptogenic activity present in astrocyte - conditioned media ( acm ) christopherson and colleagues screened a list of astrocyte - secreted proteins , including matricellular proteins , such as sparc , tenascin c , osteopontin and tsp1 , for their ability to induce synapse formation . among the twenty or so candidates tested , only purified tsp1 , when added to rgc cultures , significantly increased the number of synapses formed between rgcs , as determined both by immunocytochemistry and electron microscopy ( fig .
tsp1 could increase the synapse number in rgc cultures to a similar degree as acm , and tsp1 s activity was not additive to that of acms .
tsp2 , which is a closely related tsp family member , was also found to induce synapse formation at levels similar to that of tsp1 .
christopherson et al . found that tsp2 is the major tsp type in the acm , and that immunodepletion of tsps from acm reduced its synaptogenic effect to control levels .
taken together , these results showed that tsps are necessary and sufficient components of the synaptogenic activity in acm ( christopherson et al .
1thrombospondins induce cns synapse formation : a rgcs , when cultured alone do not form many synapses ( left ) . on the contrary , rgcs cultured in the presence of purified tsp form many synapses , which are visualized by the co - localization of the presynaptic marker bassoon ( red ) and the post - synaptic marker , homer ( green ) .
b tsp - induced synapses are ultrastructurally normal ( middle ) , with pre- and post- synaptic structures that are similar to the synapses induced by astrocytes ( astros ) or acm .
wt and ko brains were co - stained for the pre - synaptic marker , bassoon ( green ) and postsynaptic marker sap102 ( red ) .
the number of co - localized synaptic puncta was significantly lower in tsp1/2kos when compared to wts .
quantification of co - localized puncta showed a 2530% decrease in the number of synapses in the ko mice .
reproduced with permission from cell press thrombospondins induce cns synapse formation : a rgcs , when cultured alone do not form many synapses ( left ) . on the contrary ,
rgcs cultured in the presence of purified tsp form many synapses , which are visualized by the co - localization of the presynaptic marker bassoon ( red ) and the post - synaptic marker , homer ( green ) .
b tsp - induced synapses are ultrastructurally normal ( middle ) , with pre- and post- synaptic structures that are similar to the synapses induced by astrocytes ( astros ) or acm .
wt and ko brains were co - stained for the pre - synaptic marker , bassoon ( green ) and postsynaptic marker sap102 ( red ) .
the number of co - localized synaptic puncta was significantly lower in tsp1/2kos when compared to wts .
quantification of co - localized puncta showed a 2530% decrease in the number of synapses in the ko mice .
. also showed that tsp - induced synapses are ultrastructurally normal , with pre- and postsynaptic specializations similar to those observed in rgc cultures grown with an astrocyte feeding layer ( as determined by em , fig .
tsp - induced synapses were also presynaptically active , since synaptic vesicles were cycling , which was determined by lipophilic fm - dye uptake and release analysis .
however electrophysiological analysis showed that tsp - treated cells formed postsynaptically inactive ( silent ) synapses .
this lack of postsynaptic activity was due to the absence of glutamate receptors in the postsynaptic membrane ( christopherson et al .
this discovery suggested the presence of at least two steps in the establishment of cns synapses that are regulated by astrocytes ( ullian et al .
the first step is the establishment of a synaptic adhesion that leads to the recruitment of pre- and post - synaptic specializations .
the second step is the insertion of glutamate receptors into the postsynaptic site , which is mediated by an as of yet unknown astrocytic signal .
interestingly , the conversion from silent to active synapses by increasing glutamate receptors at the synapse is a mechanism also observed during developmental synaptic maturation and following the induction of long - term potentiation ( freeman 2005 ; liao et al .
whether there are other matricellular proteins that are synaptogenic and control different steps of synapse formation , maturation and synaptic plasticity is an area for future research .
in addition to the in vitro results of the synaptogenic activity of tsp1 and tsp2 , christopherson and colleagues showed that tsp1 and 2 are necessary for synapse formation in vivo by analyzing the number of synapses in the cortices of tsp1/2 double - null mice . these mice have a 2530% reduction in the number of excitatory synapses formed in their cortices during first and third postnatal weeks ( fig .
it is not yet known whether the synaptic defects seen in tsp1/2 double null - mice are specific to cortical excitatory synapses only or whether tsps are also required for excitatory synapse formation in other parts of the cns .
taken together , the results of this study identify tsps as the key synaptogenic signal coming from astrocytes in culture , and that loss of tsp1/2 function in mice significantly decreased synapse formation during development ( christopherson et al .
earlier studies exploring tsp1 - 2 expression during embryonic and postnatal development have shown that tsp protein expression can be detected in the neural plate as early as e8.5 and is present all through cns development ( oshea and dixit 1988 ; oshea et al .
tsp expression in the cns dramatically decreases in the adult rodent cns and becomes restricted to areas of neurogenesis and plasticity ( hoffman et al .
interestingly , in the nervous systems of organisms with enhanced regenerative capacity , such as newt and goldfish , tsp expression stays high even in the adult ( hoffman and oshea 1999a ; hoffman and oshea 1999b ) . in agreement with these earlier studies ,
christopherson and colleagues detected tsp1/2 protein expression in cortical lysates from an early postnatal age ( p5 ) that corresponds with the initiation of the synaptogenic period , but not in the adult cortex ( christopherson et al .
gene expression analysis of cortical cns cell types further showed that tsp1 and 2 mrnas are expressed by acutely isolated early postnatal astrocytes from mouse cerebral cortex as well as in astroglial cultures but are downregulated in mature astrocytes ( p17 ) ( table 1 , ( ( cahoy et al . 2008 ) ) . besides tsps 1 and 2 , other tsps ( tsp3 - 5 )
in contrast to other tsps , tsp4 expression is only detected in mature astrocytes ( after p17 , table 1 ( cahoy et al .
tsp4 could represent the adult isoform of tsp in the cns important for the control synaptogenesis and synaptic plasticity in the adult brain .
interestingly , tsp4 is also present in the neuromuscular junction , suggesting a function for tsps in neuromuscular junction formation ( arber and caroni 1995 ) .
recent work comparing gene expression patterns in brains of humans and other primates turned the spotlight on tsps . in humans , tsp2 and tsp4 expression levels
though speculative , these results raise the question of whether higher tsp expression levels provides the human brain with a greater capacity to form synapses , and thus enhance human cognitive functions , compared to those of other primates .
since tsps mediate a wide range of functions in modulating cell - cell and cell - matrix interactions via interacting with cell surface receptors ( bornstein et al .
2004 ) , it was postulated that tsp induces synapse formation via interacting with a neuronal receptor and that this interaction is required for the initiation of an axodendritic synaptic contact ( christopherson et al . 2005 ) .
a number of known tsp receptors are expressed by neurons , however , eroglu and colleagues found that none of the known tsp receptors were involved in the synaptogenic activity of tsp ( eroglu et al .
instead they identified a novel interaction partner for tsps , namely the non - pore - forming auxiliary subunit of calcium channels 2-1 , to be the tsp receptor involved in synapse formation .
synapse formation by tsps is mediated through an interaction between the epidermal growth factor - like repeats of tsps and the von - willebrand factor a like - domain of 2-1 .
furthermore , sirna knockdown of 2-1 revealed that 2-1 is necessary for tsp - induced synapse formation in vitro .
the role of 2-1 in synapse formation is not dependent on its known roles in calcium channel function and trafficking , suggesting that this molecule might have other functions in the cell that do or do not involve calcium channels . in agreement with in vitro findings , over expression of 2-1 , specifically in neurons , in a transgenic mouse line , results in a significant increase in the number of excitatory synapses in vivo ( eroglu et al .
in addition to binding tsps , 2-1 is a known target for the anti - convulsant , anti - neuropathic pain drug gabapentin ( gbp ) which is known to mediate its therapeutic function through this interaction ( field et al .
gbp blocked tsp-2-1 interaction and astrocyte / tsp - induced synapse formation in vitro ( eroglu et al .
in addition , gbp injection into neonatal mice during the first postnatal week led to a very severe reduction in the number of excitatory synapses , which was as low as ten percent of control levels in half of gbp - injected animals ( eroglu et al .
the magnitude of reduction seen in this study far exceeded that seen in tsp1/2 double kos ( christopherson et al .
2005 ) , suggesting that that tsp3 and 4 might partially compensate for the loss of tsp1 and 2 in the kos .
the ability of gbp to strongly decrease synapse formation in the brains of wild - type mice points to a critical role for tsp-2-1 interactions in driving synaptogenesis in vivo . in summary these findings add to the growing data showing that astrocytes and the tsps they release contribute to synapse formation in the developing brain , and identify 2-1 as a new molecule that regulates synapse formation .
future research investigating how the tsp-2-1 interaction leads to synapse formation is necessary to understand the intracellular signaling molecules and mechanisms that govern the process of synapse formation in the cns .
2-1 is also expressed at high levels outside the cns , in tissues including skeletal and cardiac muscles and bone ( arikkath and campbell 2003 ) .
extensive previous research on tsp function has been performed in these non neuronal tissues , therefore , it will be interesting to explore in the future whether the tsp-2-1 interaction is also involved in some of the known functions of tsp in these tissues .
it is a recurring theme for many matricellular proteins , including tsps , that upon injury to the nervous system their expression is upregulated .
for example the levels of tsps 1 and 2 are increased after a stroke ( lin et al .
purinergic signaling and mechanical stimulation have been shown to play a role in tsp upregulation in astrocytes ( tran and neary 2006 ) .
liauw and colleagues investigated whether tsp1/2 were required for synaptic and functional recovery after strokes ( liauw et al . 2008 ) .
to do so , they induced focal ischemia in 8- to 12-week - old wild - type ( wt ) and tsp-1/2 double knockout ( tsp1/2 ko ) mice by unilateral occlusion of the distal middle cerebral artery and the common carotid artery .
these investigators showed that in wt mice tsp 1 and 2 mrnas and protein levels were increased .
they compared wt and ko mice for angiogenesis , synaptic density , axonal sprouting , infarct size , and functional recovery at different time points .
tsp-1/2 ko mice exhibited a significant deficit in their ability to recover , particularly in the tongue protrusion test of motor function , when compared with wt mice .
previously , the increase of tsps after a stroke was postulated to take part in post - ischemic angiogenesis ( lin et al . 2003 ) .
however , liauw and colleagues found no differences in infarct size and blood vessel density between the wt and tsp1/2ko groups , suggesting that angiogenesis was not significantly affected by the lack of tsps .
instead tsp-1/2 ko mice exhibited significant deficits in synaptic density and axonal sprouting ( liauw et al .
since a deficiency of tsp-1/2 leads to impaired recovery after a stroke , mainly due to impaired synapse formation and axonal outgrowth , it is likely that tsps are involved in a synaptic recovery process after injury in the adult cns .
understanding how the brain remodels its neuronal networks is a major goal of neurobiology , as these processes underlie learning , memory and recovery from injury . to determine whether astrocytes and the tsps they secrete are involved in lesion - induced synaptic remodeling in the developing cns , eroglu and colleagues utilized a well - established developmental plasticity paradigm , the barrel cortex plasticity assay ( eroglu et al . 2009 ) .
the nerves that innervate the major whiskers on the snout of the mouse project to the brain as a topographically ordered somatotopic
map where afferent axons and target cells form ordered modules that recapitulate the structural organization of the whisker pad ( erzurumlu et al .
the somatotopic map in the cortex forms a pattern consisting of what are known as
the barrel cortex exhibits structural changes in its circuitry in response to peripheral whisker manipulations .
thus if a row of whiskers on the snout is lesioned during a critical period of postnatal development ( the first three postnatal days in mice ) , the corresponding barrels in the cortex shrink and fuse , while axons that innervate the neighboring barrels invade the territory vacated by projections from the lesioned whiskers ( van der loos and woolsey 1973 ) .
interestingly , inhibition of tsp - mediated synapse formation , either by injection of gbp or by the use of tsp1/2-deficient mice , led to extensive outgrowth of the intact afferents that extended beyond the affected region .
these manipulations caused barrels to lose form and fuse in varying degrees , a phenotype which was never observed in saline - injected or wild - type mice ( eroglu et al .
these findings suggest that astrocyte - secreted tsps induce the synapse formation required for rewiring of barrels following injury . blocking tsp - induced synapse formation may lead to the loss of a
stop and connect signal such that the axons continue to search for an appropriate target , resulting in the inability to reform barrels correctly .
interestingly , neither the gbp - injected mice nor the tsp1/2 ko mice had problems in the normal establishment of the barrels in the unlesioned control hemisphere , suggesting that tsps specifically play a role in synaptic remodeling - plasticity upon injury in this system .
it is possible that a whisker lesion - dependent upregulation of tsps , or their neuronal receptor 21 , might be necessary to mediate this function .
in fact an increase in 2-1 levels after injury has been demonstrated to occur in the spinal nerve ligation model of neuropathic pain ( li et al . 2004 ) .
together , these data suggest that the increase in the expression levels of 2-1 and tsps could be an essential part of the synaptic remodeling in response to synapse loss following injury . in addition , since gbp is a drug against neuropathic pain and is able to block the tsp-2-1 interaction and resulting synapse formation , it is possible that its therapeutic function includes the inhibition of excess synapse formation induced by upregulation of these molecules after injury to the cns .
these findings also highlight tsps as potential drug targets for diseases such as neuropathic pain and epilepsy .
tenascin c ( tn - c ) is highly expressed by astrocytes at early stages of the development of the cns while its expression is strongly reduced in the adult cns ( bartsch et al .
however in the mature cns , tn - c is still expressed by specific cell populations , notably those in close proximity to areas of active neurogenesis , such as the hippocampus , subventricular zone borders and the rostral migratory stream ( bartsch et al .
these expression patterns suggest important roles for tn - c in the remodeling of the cns , both during development and in the adult .
studies using either neuron or glial cultures have revealed that tn - c can alter cns cell behavior significantly , often in a cell type - specific manner .
for example , tn - c has been reported to promote axon outgrowth and modulate growth cone dynamics , as well as to inhibit the migration of oligodendrocyte precursor cells and stimulate granule cell migration ( crossin 1994 ; faissner and steindler 1995 ; husmann et al . 1995 ; kiernan et al .
given tn - c s extensive expression and its strong effects in cell culture , the observation that tn - c - null mice show no obvious abnormalities was very surprising and suggested redundancy of tn - c function ( erickson 1993 ) .
however , later studies have revealed behavioral abnormalities and alterations in neurotransmitter levels in the adult cns ( fukamauchi et al .
a homolog of tn - c , tenascin r ( janusin ) , is also expressed in cns , mainly by oligodendrocyte lineage cells ( bartsch et al .
1993 ) , and might compensate for lack of tn - c in the cns .
another possibility is that tn - c and other matricellular proteins have specific and important roles during early stages of development , but that later developmental processes are able to correct for the loss of this matricellular protein . in support of this possibility
, analyses of the developing cns in tn - c knockout mice revealed contributions of tn - c that were not apparent in the adult brain .
these studies confirmed the role of tn - c in the cell migration of oligodendrocyte precursors , and demonstrated novel roles for tn - c in the regulation of neural precursor cell proliferation ( garcion et al .
interestingly , reduced levels of programmed cell death were observed in tn - c ko mice which may have provided a corrective mechanism that accounted for the grossly normal phenotype ( garcion et al .
recent evidence also suggested that tn - c contributes to the generation of a stem cell niche within the subventricular zone that acts to orchestrate growth factor signaling so as to accelerate neural stem cell development ( garcion et al .
colleagues found that there was abnormally high neuronal density , astrogliosis and reduced density of parvalbumin - positive interneurons in the somatosensory and motor cortices of adult tn - c ko compared to those of wild - type mice ( irintchev et al .
the ratios of oligodendrocytes to neurons and of inhibitory to excitatory neurons were reduced in the kos as opposed to in wt animals .
interestingly , layer v pyramidal neurons in the tn - c ko animals were found to have abnormal dendritic morphology and abnormal distribution of stubby spines suggesting roles for tn - c in regulation of neurite outgrowth and spinogenesis in vivo .
significantly enhanced responses to whisker stimulation were recorded in the barrel and in the motor cortices of ko mice compared to wt animals .
the authors suggested that the increased excitation observed in these mice is most likely due to a reduction in inhibitory neuronal signaling ( irintchev et al . 2005 ) .
it is possible that part of the phenotypes observed in tn - c - deficient mice could be due to the lack of expression of this protein , not only in astrocytes or other glia , but also in neurons . taken together , these studies suggest that tn - c is critical for determination of neuronal cell - fate and for cell migration and maturation in the developing cns .
similar to tn - c , sparc and its close homolog , hevin , are highly expressed in the developing cns .
early postnatal expression of sparc is mostly restricted to radial glial cells , and this expression seems to subside with development , coinciding with the disappearance of radial glia ( vincent et al .
is enriched in specialized radial glial derivatives , including the mller glia of the retina and the bergmann glia of the cerebellum .
sparc is also expressed by blood vessels , and by some cells along the rostral migratory stream , which are restricted to the subventricular zone in adulthood ( fig .
astrocytes and schwann cells also secrete sparc both in vivo and in vitro ( bampton et al . 2005 ; mendis et al .
1995 ) and schwann cell - secreted sparc was shown to promote retinal ganglion cell survival and neurite outgrowth ( bampton et al . 2005 ) .
2sparc and hevin expression in the adult brain . a in situ analysis of sparc and hevin expression in 55 day - old mouse brain .
expression analysis ( right ) is a heat map for intensity of the in situ signal ( right ) .
hevin staining was observed in the synaptic cleft closely associated with the postsynaptic element . po = postsynaptic , pr = presynaptic .
( right ) hevin staining was also present on perisynaptic astrocyte processes outlined by dashed lines .
a in situ analysis of sparc and hevin expression in 55 day - old mouse brain .
expression analysis ( right ) is a heat map for intensity of the in situ signal ( right ) .
hevin staining was observed in the synaptic cleft closely associated with the postsynaptic element . po = postsynaptic , pr = presynaptic .
( right ) hevin staining was also present on perisynaptic astrocyte processes outlined by dashed lines .
images from ( lively et al . 2007 ) . reproduced with permission from springer netherlands of the matricellular proteins discussed in this review , hevin s expression in the cns is perhaps the strongest .
hevin s expression increases during early postnatal development , coinciding well with the synaptogenic period and stays high in the adult brain ( lively et al . 2007 ; lively and brown 2008a ; mendis et al . 1994 , 1996b ) ( fig .
hevin mrna is expressed by almost all cell types in the brain , but the levels in astrocytes are extremely high when compared to that of any other cell type ( table 1 , ( cahoy et al .
one interesting feature of hevin is that it was initially identified as a component of synaptosomes and named synaptic cleft protein 1 ( sc1 ) ( johnston et al .
em immunolabeling studies confirmed that hevin is concentrated at synaptic junctions , as well as along the astrocytic processes that surround synapses ( fig .
therefore hevin is a prime candidate for future studies of the role of astrocyte - secreted proteins in synapse formation and function .
similar to tsp1/2 and tn - c - deficient mice , sparc and hevin nulls are viable and do not display any gross abnormalities ( bassuk et al . 1999 ; gilmour et al .
however , sparc - null mice develop severe lens degeneration in adulthood ( bassuk et al .
future detailed physiological and behavioral studies are needed to uncover the roles these proteins play in the development and maintenance of the nervous system .
like tsps , hevin and sparc expression is also upregulated after injury to the cns , correlating with the onset of reactive gliosis ( liu et al .
2005 ; lively and brown 2007 , 2008b ; mckinnon and margolskee 1996 ; mendis et al .
in addition , sparc delays tumor growth in vitro and in vivo , which reveals the molecule as a potential antitumorigenic drug target ( menon et al .
tenascin c ( tn - c ) is highly expressed by astrocytes at early stages of the development of the cns while its expression is strongly reduced in the adult cns ( bartsch et al .
however in the mature cns , tn - c is still expressed by specific cell populations , notably those in close proximity to areas of active neurogenesis , such as the hippocampus , subventricular zone borders and the rostral migratory stream ( bartsch et al .
these expression patterns suggest important roles for tn - c in the remodeling of the cns , both during development and in the adult .
studies using either neuron or glial cultures have revealed that tn - c can alter cns cell behavior significantly , often in a cell type - specific manner .
for example , tn - c has been reported to promote axon outgrowth and modulate growth cone dynamics , as well as to inhibit the migration of oligodendrocyte precursor cells and stimulate granule cell migration ( crossin 1994 ; faissner and steindler 1995 ; husmann et al . 1995 ; kiernan et al .
given tn - c s extensive expression and its strong effects in cell culture , the observation that tn - c - null mice show no obvious abnormalities was very surprising and suggested redundancy of tn - c function ( erickson 1993 ) .
however , later studies have revealed behavioral abnormalities and alterations in neurotransmitter levels in the adult cns ( fukamauchi et al .
a homolog of tn - c , tenascin r ( janusin ) , is also expressed in cns , mainly by oligodendrocyte lineage cells ( bartsch et al .
1993 ) , and might compensate for lack of tn - c in the cns .
another possibility is that tn - c and other matricellular proteins have specific and important roles during early stages of development , but that later developmental processes are able to correct for the loss of this matricellular protein . in support of this possibility
, analyses of the developing cns in tn - c knockout mice revealed contributions of tn - c that were not apparent in the adult brain .
these studies confirmed the role of tn - c in the cell migration of oligodendrocyte precursors , and demonstrated novel roles for tn - c in the regulation of neural precursor cell proliferation ( garcion et al .
interestingly , reduced levels of programmed cell death were observed in tn - c ko mice which may have provided a corrective mechanism that accounted for the grossly normal phenotype ( garcion et al .
recent evidence also suggested that tn - c contributes to the generation of a stem cell niche within the subventricular zone that acts to orchestrate growth factor signaling so as to accelerate neural stem cell development ( garcion et al .
colleagues found that there was abnormally high neuronal density , astrogliosis and reduced density of parvalbumin - positive interneurons in the somatosensory and motor cortices of adult tn - c ko compared to those of wild - type mice ( irintchev et al .
the ratios of oligodendrocytes to neurons and of inhibitory to excitatory neurons were reduced in the kos as opposed to in wt animals .
interestingly , layer v pyramidal neurons in the tn - c ko animals were found to have abnormal dendritic morphology and abnormal distribution of stubby spines suggesting roles for tn - c in regulation of neurite outgrowth and spinogenesis in vivo .
significantly enhanced responses to whisker stimulation were recorded in the barrel and in the motor cortices of ko mice compared to wt animals .
the authors suggested that the increased excitation observed in these mice is most likely due to a reduction in inhibitory neuronal signaling ( irintchev et al . 2005 ) .
it is possible that part of the phenotypes observed in tn - c - deficient mice could be due to the lack of expression of this protein , not only in astrocytes or other glia , but also in neurons . taken together , these studies suggest that tn - c is critical for determination of neuronal cell - fate and for cell migration and maturation in the developing cns .
similar to tn - c , sparc and its close homolog , hevin , are highly expressed in the developing cns . early postnatal expression of sparc is mostly restricted to radial glial cells , and this expression seems to subside with development , coinciding with the disappearance of radial glia ( vincent et al .
is enriched in specialized radial glial derivatives , including the mller glia of the retina and the bergmann glia of the cerebellum .
sparc is also expressed by blood vessels , and by some cells along the rostral migratory stream , which are restricted to the subventricular zone in adulthood ( fig .
astrocytes and schwann cells also secrete sparc both in vivo and in vitro ( bampton et al . 2005 ; mendis et al .
1995 ) and schwann cell - secreted sparc was shown to promote retinal ganglion cell survival and neurite outgrowth ( bampton et al . 2005 ) .
a in situ analysis of sparc and hevin expression in 55 day - old mouse brain .
expression analysis ( right ) is a heat map for intensity of the in situ signal ( right ) . blue = low , orange = high .
hevin staining was observed in the synaptic cleft closely associated with the postsynaptic element . po = postsynaptic , pr = presynaptic .
( right ) hevin staining was also present on perisynaptic astrocyte processes outlined by dashed lines .
a in situ analysis of sparc and hevin expression in 55 day - old mouse brain .
expression analysis ( right ) is a heat map for intensity of the in situ signal ( right ) .
hevin staining was observed in the synaptic cleft closely associated with the postsynaptic element . po = postsynaptic , pr = presynaptic .
( right ) hevin staining was also present on perisynaptic astrocyte processes outlined by dashed lines .
reproduced with permission from springer netherlands of the matricellular proteins discussed in this review , hevin s expression in the cns is perhaps the strongest .
hevin s expression increases during early postnatal development , coinciding well with the synaptogenic period and stays high in the adult brain ( lively et al . 2007 ; lively and brown 2008a ; mendis et al . 1994 , 1996b ) ( fig .
hevin mrna is expressed by almost all cell types in the brain , but the levels in astrocytes are extremely high when compared to that of any other cell type ( table 1 , ( cahoy et al .
one interesting feature of hevin is that it was initially identified as a component of synaptosomes and named synaptic cleft protein 1 ( sc1 ) ( johnston et al .
em immunolabeling studies confirmed that hevin is concentrated at synaptic junctions , as well as along the astrocytic processes that surround synapses ( fig . 2b , ( lively et al . 2007 ; lively and brown 2008a ) ) .
therefore hevin is a prime candidate for future studies of the role of astrocyte - secreted proteins in synapse formation and function .
similar to tsp1/2 and tn - c - deficient mice , sparc and hevin nulls are viable and do not display any gross abnormalities ( bassuk et al .
however , sparc - null mice develop severe lens degeneration in adulthood ( bassuk et al .
future detailed physiological and behavioral studies are needed to uncover the roles these proteins play in the development and maintenance of the nervous system . like tsps
, hevin and sparc expression is also upregulated after injury to the cns , correlating with the onset of reactive gliosis ( liu et al .
2005 ; lively and brown 2007 , 2008b ; mckinnon and margolskee 1996 ; mendis et al . 1996a , 1998 , 2000 ) .
in addition , sparc delays tumor growth in vitro and in vivo , which reveals the molecule as a potential antitumorigenic drug target ( menon et al .
matricellular proteins tsp1 - 4 , tn - c , sparc , and hevin are expressed mainly by astrocytes in the cns .
they serve important roles both in vitro and in vivo in neuronal cell development , migration and in the establishment of synaptic connections .
the expression of these proteins is upregulated in disease conditions and in response to injury to the cns suggesting a role for these proteins in cns repair mechanisms .
future studies will determine whether matricellular proteins other than tsps are involved in synapse formation , function and plasticity .
Output:
| matricellular proteins , such as thrombospondins ( tsps1 - 4 ) , sparc , sparc - like1 ( hevin ) and tenascin c are expressed by astrocytes in the central nervous system ( cns ) of rodents . the spatial and temporal expression patterns of these proteins suggest that they may be involved in important developmental processes such as cell proliferation and maturation , cell migration , axonal guidance and synapse formation .
in addition , upon injury to the nervous system the expression of these proteins is upregulated , suggesting that they play a role in tissue remodeling and repair in the adult cns .
the genes encoding these proteins have been disrupted in mice .
interestingly , none of these proteins are required for survival , and furthermore , there are no evident abnormalities at the gross anatomical level in the cns .
however , detailed analyses of some of these mice in the recent years have revealed interesting cns phenotypes . here
we will review the expression of these proteins in the cns .
we will discuss a newly described function for thrombospondins in synapse formation in the cns in detail , and speculate whether other matricellular proteins could play similar roles in nervous system development and function . |
PubmedSumm118751 | ***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: glaucoma is the most common optic neuropathy which is characterized by progressive loss of retinal ganglion cells , the excavation of the optic nerve head , associated with defects in the visual field ( 1 ) .
multiple factors are equally active in cell bodies and their axons leading to the death of retinal ganglion cells .
it is not a disease , but the final result of united and yet completely unidentified cellular and subcellular processes and effects of many factors responsible for changes in retinal ganglion cells leading to their accelerated apoptosis .
since glaucoma is a sindrome of eye disease in which there is damage to the optic nerve , and if left untreated can result in total loss of sight .
defects in the nerve fiber layer of the retina prior to visible changes at the head of the optic nerve and defects in the visual field are detected when it is already 40% of axons irretrievably lost ( 2 ) .
glaucoma is the second cause of blindness worldwide , after cataracts , and unlike cataract , glaucoma causes irreversible blindness . according to the world health organization ( who ) and the world association of glaucomatologist ( wgo ) , in the year 2010 , 66.8 million people worldwide suffer from glaucoma , and 6.7 million are blind from this disease ( 3 ) .
it manifests itself in damage to the optic nerve , loss of vision and eventually decline in central visual acuity ( 4 ) . in order to understand and assess the presence of glaucomatous changes in the optic nerve ,
it is necessary to know and understand the optic nerve head characteristics of healthy people . as in other biological characteristics ,
changes on the optic nerve head differ among healthy population , impeding recognition of pathological changes ( 5 ) .
the relationship between the optic disc size , neuroretinal rim and cup / disc ratio , are crucial in identifying glaukomatous changes in the optic nerve head ( 6 ) .
size depends on the size of the optical disc , and the size of the bulbus .
eyes with small scleral canal have small optical discs , and those with large channels have large discs ( 7 ) .
different ways of entering the optic nerve in the sclera provides irregular and unusual look like optical discs such as tilted disc .
according to recent research , the link between myopia and glaucoma remains unexplained in most cases , mainly due to the fact that it is difficult to sort out the structural and functional abnormalities we meet in myopia from the real glaucoma changes ( 8) . there is strong epidemiological evidence linking myopia and glaucoma .
miopic optic disc can be a major challenge in terms of correct diagnosis of glaucoma . by using optical coherence tomography
, it was found that myopia is associated with changes in retinal nerve fiber layer , in the form of temporal displacement and the thinning of the upper and lower segments of retinal layers of nerve fibers .
as is the case with all the progressive condition , it is often not possible to distinguish glaucomatous from nonglaucomatous changes of the optical disc based on a single examination , but the follow up by the oct analysis of the optic nerve head and associated changes in the visual field may result in the usefull data ( 9 ) .
although myopia is a known risk factor for glaucoma , it can also lead to structural and functional defects that can not be distinguished from those caused by glaucoma ( 10 ) .
this is a prospective - retrospective , comparative , randomized clinical trial that included 150 patients , 97 were female and 53 male .
the age of patients ranged from 18 to 80 years . in order to make scientifically valuable statistical comparison ,
100 eyes in 3 groups of patients of both sexes : group i - patients with glaucoma , group ii - patients with myopia and glaucoma , group iii - patients only with myopia .
criteria for inclusion in the study : patients with myopia , the patients of both sexes caucasian , patients older than 18 and younger than 80 years , patients who are diagnosed with glaucoma , patients who , in addition to ophthalmologic tests carried out and test with soct 3d and computerized perimetry test , we took into account only those results in which the reliability factor ( rf ) was in the permissible overdrafts , under 15% . criteria for exclusion from the study : patients with a previous ophthalmic surgery or laser treatment to the eye that is the subject of tests , patients with other diseases of the eye ( macular disease , hemophtalmos , cataracts , uveitis , keratitis ) , patients with head injuries and eye patients neuroophthalmological diseases and diseases of the retina that may affect the visual field disturbance ( neuritis , eye contusion , retinopathy ) , patients with neuropsychiatric disorders , patients with claustrophobia and inability to withstand the tests of the visual field to the end , patients in which the reliability factor in excess of 15% , patients being treated with chemotherapeutic agents , anti - metabolites , patients with severe systemic diseases .
all patients after anamnesis underwent following ophthalmological examination : natural visual acuity and best corrected visual acuity , applanation tonometry goldman , biomicroscope examination autorefractometry , gonioscopy , fundus examination - direct ophthalmoscopy ( stereobiomicroscopy volk lens + 90d ) , three - dimensional spectral optical coherence tomography ( soct 3d ) , static computerized perimetry ( kowa ) .
the the study included 300 eyes of patients who were divided into three equal groups , according to the criteria for inclusion in the study .
the first group includes subjects diagnosed with glaucoma and analyzed 100 eyes with glaucoma , the second group includes subjects who have been diagnosed with glaucoma and myopia ( n = 100 ) , and the third group includes participants only with myopia ( n = 100 ) .
table 1 shows the average age of the respondents in relation to the experimental group .
the average age of patients with glaucoma was 65.83 14.15 years ( 18 - 86 ) , while the average age of patients with glaucoma and myopia was 64.26 12.68 years ( 27 - 82 ) .
the average age of patients with myopia amounted to 50.09 17 years ( 23 - 81 ) , and the participants of this group were significantly younger than did those in the first two groups , f = 34,668 ; p < 0.05 ( table 2 ) . the average age of the respondents in relation to the study group gender structure of respondents of the total number of subjects included in this study ( n300 ) , males were 35.3% and female 64.7% .
in all three groups dominated the respondents were female and not a statistically significant difference compared to the test group , 2 = 0.381 ; p = 0.827 .
an analysis of the average value of the height of the diopter in patients with myopia in subjects which in addition to glaucoma and myopia have established a statistically significant difference ( table 3 ) .
the average height of the diopter in patients with glaucoma and myopia amounted to -3.77 1.55 , while in patients with myopia it was only -2.49 1.25 , f = 40,940 ; p < 0.05 ( table 4 )
. statistically significant difference was found in ddls values in relation to rnfl findings in patients with glaucoma in all three of optical disc sizes using hi - square test ( table 5 ) . in the group of patients that have had a large optic disc ,
the average cup disc diameter size was significantly higher in patients with myopia than in the other two test groups ( p < 0.05 ) .
however , in patients who have a medium optic disc size , the cup disc diameter was significantly higher in patients who have had myopia and glaucoma , as compared to subjects who had only glaucoma or just myopia ( p < 0.05 ) . in patients with small disc was no significant difference in the average cup disc diameter ( p = 0.139 ) ( table 6 ) .
myopia degree in relation to the study group ddls impact on rnfl findings in relation to the study group and the size of the optic disc average cup disc diameters in relation to the optic disc size average ddls values in relation to the optic disc size through the analysis of the average ddls values in relation to the optic disc size of the respondents in the study groups we established a statistically significant difference only for large discs considering the ddls values in other participants study groups ( p = 0.033 ) , in patients who have had small and medium disc size a statistically significant difference has not been established .
it was also found that respondents with a higher degree of visual field changes have greater ddls values ( chart 1 ) .
it is important to note that the subjects with terminal stage in visual field loss in the group with diagnosed glaucoma had average ddls value 7.11 , and those with a joint diagnosis of glaucoma and myopia 8.75 of the ddls ( chart 2 ) . by determining the average ddls values in relation to the optic disc mophology in all study groups we established a statistically significant difference among the three groups considering the shape and ddls values ( chart 3 ) .
respondents with tilted discs had a significantly higher ddls values in relation to the patients with other forms of the disc in all three groups ( p < 0.05 ) .
average ddls values in relation to the visual field changes of the respondents in all study groups average ddls values compared to the optic disc morphology in all analyzed groups the average value of myopia in relation to the size and shape of the optic disc
previous studies on the relationship between myopia and open - angle glaucoma are based on the results of observational studies .
however , according to recent findings , based on the available studies , the systematic approach to estimate the association between myopia and glaucoma does not exist .
myopic eyes have a longer axial length . experimental models of myopia and epidemiological data have shown that myopia is most often the result of disproportionate elongation of the posterior segment of the eye , which physically limits the fibrous sclera . in general , the axial length is the most important element of the refraction of the eye , which most determines the occurrence of refractive errors ( 11 ) .
this could contribute to the greater sensitivity of the optic nerve head in glaucoma changes ( 12 ) .
no one knows with absolute certainty what causes myopia , but they noticed a certain connection between the occurrence of myopia and certain factors that are reasonably believed to have a significant role in its development .
some of the potential risk factors are : race , ethnicity , industrial development , heredity , education , profession , environment , gender , diet , stress , and other factors .
gvozdenovic and colleagues in their study concluded that optic discs of glaucoma patients with high myopia have a larger diameter , larger and more irregular distributed neuroretinal rim zone damage and thinner retinal nerve fiber layer than in glaucoma patients with low myopia ( 4 ) .
kimura and colleagues have been examining the damage of retinal nerve fiber layer rnfl for early glaucoma in eyes with high myopia , reaching important results .
these results suggest that in high myopia common nerve damage is the damage of the papillomacular nerve fiber layer in early stage of glaucoma ( 10 ) .
the evaluation of morphological parameters of the optic nerve head and peripapillary areas of testing in patients with different degree of myopia we are one step closer to identifying changes in the optic disc as the earliest signs related to glaucoma . via analysis of comorbidity of glaucoma and myopia ,
it is possible to make the algorithm of diagnostic techniques and procedures for early detection of glaucoma .
disc damage likelihood scale ( ddls ) is a new system for assessing glaucomatous damage of the optic disc which strongly correlates with the degree of visual field loss .
the average age of the respondents ranged from 50 to 66 years and in all three groups dominated female patients .
we did not found a statistically significant effect of age on the development of glaucoma .
the analysis of the results did not established influence of gender on the form of an optic disc .
the highest percentage of male respondents ( 50.9% ) and female ( 62.4% ) had a round optic disc , and then tilted ( 22.3% ) and oval ( 14.3% ) .
the highest degree of myopia , regerdless the optic disc size had patients with tilted optic disc in all three groups .
the highest degree of myopia in category of tilted optic discs had patients with large disc(4.05 + -0.65 ) .
values of the degree of myopia have linearly declined in relation to the size of the oblique disc .
the analysis of the results revealed that the subjects who had a higher degree of myopia associated with glaucoma had frequent parapapillar atrophy of alpha and beta zones .
the highest percentage of subjects with parapapillar changes were in the group of patients who had other than glaucoma and myopia ( 62% ) , then in the group of patients with glaucoma only ( 56% ) .
Output:
| introduction : glaucoma is the most common optic neuropathy which is characterized by progressive loss of retinal ganglion cells , the excavation of the optic nerve head , associated with defects in the visual field . it is not a disease , but the final result of united and yet completely unidentified cellular and subcellular processes and effects of many factors responsible for changes in retinal ganglion cells leading to their accelerated apoptosis.methods:this is a prospective - retrospective , comparative , randomized clinical trial that included 150 patients , 97 were female and 53 male .
the age of patients ranged from 18 to 80 years.results:the highest degree of myopia in category of tilted optic discs had patients with large disc ( 4.05 + -0.65 ) .
values of the degree of myopia have linearly declined in relation to the size of the oblique disc .
the analysis of the results revealed that the subjects who had a higher degree of myopia associated with glaucoma had frequent parapapillar atrophy of alpha and beta zones .
the highest percentage of subjects with parapapillar changes were in the group of patients who had other than glaucoma and myopia ( 62% ) , then in the group of patients with glaucoma only ( 56%).conclusion : previous studies on the relationship between myopia and open - angle glaucoma are based on the results of observational studies .
however , according to recent findings , based on the available studies , the systematic approach to estimate the association between myopia and glaucoma does not exist .
disc damage likelihood scale ( ddls ) is a new system for assessing glaucomatous damage of the optic disc which strongly correlates with the degree of visual field loss . |
PubmedSumm118752 | ***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 generally whitish , yellowish , or greenish vaginal discharge in females that might be normal or a symptom of infection .
it is almost mucus discharge , which exhibit exfoliation of vaginal epithelial cells due to estrogen influence on the vaginal mucosa .
leucorrhea is a well - known disease in iranian traditional medicine ( itm ) . in their manuscripts , the word
sayalan - e rahem was used by avicenna and some other iranian traditional practitioners to describe this condition .
ancient practitioners believed that excessive residue ( kesrate fozool ) and weakness of digestion ( zaafe hazm ) were the main causes of leucorrhea , for which herbal therapy was the main proposed treatment . in the present study ,
in this research , six iranian traditional textbooks including canon of medicine ( avicena 980 - 1037 ad ) , a - hawi ( razes 865 - 925 ad ) , tuhfat ul - momineen ( momen tonekaboni , 17th century ) , makhzan - ul - adwiah ( aghili 18th century ) , ikhtiarat badii ( ansari 1329 - 1404 ad ) , and al - jmi li - mufradt al - adwiyawa al - aghdhiy ( ibn al - baitar 1197 ad ) were studied and searched for anti - leucorrhea medicines . then the herbal medicines were selected and scored depending on their frequency in the above - mentioned textbooks .
this study introduced many materia medica with anti - leucorrhea activity and among them seven herbs including rubus fruticosus l. , rhus coriaria l. , phoenix dactylifera l. , pimpinella anisum l. , rumex acetosa l. , olea europaea l. and quercus lusitanica lam . showed the most repetition in itm prescriptions
these herbs can be introduced as new anti - leucorrhea herbal medicines for clinical research .
Output:
| background : leucorrhea or vaginal discharge is a conventional complaint . it is generally whitish , yellowish , or greenish vaginal discharge in females that might be normal or a symptom of infection . it is almost mucus discharge , which exhibit exfoliation of vaginal epithelial cells due to estrogen influence on the vaginal mucosa .
it is important to identify the differences between physiologic and pathologic discharges .
leucorrhea is a well - known disease in iranian traditional medicine ( itm ) . in their manuscripts , the word
sayalan - e rahem was used by avicenna and some other iranian traditional practitioners to describe this condition .
ancient practitioners believed that excessive residue ( kesrate fozool ) and weakness of digestion ( zaafe hazm ) were the main causes of leucorrhea , for which herbal therapy was the main proposed treatment . in the present study , medicinal plants used in itm for leucorrhea are introduced.methods:in this research , six iranian traditional textbooks including canon of medicine ( avicena 980 - 1037 ad ) , a - hawi ( razes 865 - 925 ad ) , tuhfat ul - momineen ( momen tonekaboni , 17th century ) , makhzan - ul - adwiah ( aghili 18th century ) , ikhtiarat badii ( ansari 1329 - 1404 ad ) , and al - jmi li - mufradt al - adwiyawa al - aghdhiy ( ibn al - baitar 1197 ad ) were studied and searched for anti - leucorrhea medicines .
then the herbal medicines were selected and scored depending on their frequency in the above - mentioned textbooks .
additional attention was paid to provide the most suitable scientific name for each plant.results:this study introduced many materia medica with anti - leucorrhea activity and among them seven herbs including rubus fruticosus l. , rhus coriaria l. , phoenix dactylifera l. , pimpinella anisum l. , rumex acetosa l. , olea europaea l. and quercus lusitanica lam .
showed the most repetition in itm prescriptions.conclusion:these herbs can be introduced as new anti - leucorrhea herbal medicines for clinical research . |
PubmedSumm118753 | ***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: rhabdomyosarcomas ( rmss ) are a group of soft - tissue malignant tumors which derive from primitive skeletal muscle tissue that mainly affect children and adolescents .
rmss are very rare in adults , where they are usually located in the extremities .
a previously healthy 32-year - old male presented at our ent ( ear , nose and throat ) outpatient clinic after experiencing a parotid region swelling for 2 months .
the patient was treated surgically by excising the mass and by modified radical ipsilateral neck dissection .
the patient received radiochemotherapy , and he is still alive with no evidence of disease spread 1 year after diagnosis .
this is the first case of a masseter alveolar rms to be reported in the literature in a patient older than 25 years ; it highlights the broad spectrum of neoplasms that cause parotid region swellings and the importance of considering rare tumors during differential diagnosis .
rhabdomyosarcomas ( rmss ) are a group of soft - tissue malignant tumors which derive from primitive skeletal muscle tissue and affect children and adolescents .
rmss are classified according to their location in the extremities versus axial lesions ; the latter subgroup arises from the head and neck , the paraspinal region , and the genitourinary tract .
the head and neck region is the most common axial site in children , and these rmss are divided into three subgroups : orbital , parameningeal , and nonorbital nonparameningeal .
the international classification divides rmss into three histological subgroups with different prognoses : the embryonal subtype with two variants , i.e. spindle cell and botryoid , with a better prognosis ; the alveolar subtype ; and unspecified rms with a poor prognosis .
most rmss are sporadic , and there is no evidence of risk factors , although a small subgroup is linked with familiar syndromes such as neurofibromatosis and li - fraumeni syndrome .
chemello et al . also reported a case of embryonal rms of the masseter muscle in a 12-year - old girl , who had previously been irradiated for a bilateral retinoblastoma .
a previously healthy 32-year - old male nonsmoker presented at our ent ( ear , nose and throat ) outpatient clinic complaining of a painless swelling in the right parotid region , which had been increasing for 2 months .
the macroscopic examination reported a firm mass measuring about 3.5 1.5 cm with shaded limits , while ipsilateral lymphadenopathy was also present .
hematological and infectious diseases were evaluated , but both pathologies were negative based on hematological and microbiological examinations .
the patient was submitted to neck ultrasound , which identified a hyperechogenic nodular mass measuring about 2.5 1.3 cm in the right parotid region , with concomitant ipsilateral enlarged cervical nodes .
multislice computed tomography ( ct ) detected a mass in the right masseter with a maximum diameter of approximately 2.2 cm with central necrosis and perifocal inflammatory reaction , which was associated with thickening of the masseter muscle . at the lower parotid pole
, there was a coexisting area of high enhancement , while multiple enlarged cervical nodes were found in the level iii and iv cervical nodes , with a diameter of 11.8 cm ( fig . 1 , fig .
2 ) . magnetic resonance imaging ( mri ) with paramagnetic contrast identified an oval mass in the right masseter muscle , which was mildly hyperintense in t1-weighted images and hyperintense in long repetition time ( tr ) , with regular margins and high contrast intake .
the concomitant low pole mass had a cystic appearance with regular margins and low intensity in t1-weighted images and a higher intensity in short tau inversion recovery ( stir ) .
the patient was also submitted to f - fdg positron emission tomoscintigraphy ( pet ) , which indicated a high pathological increase in the glucose metabolism in the intramasseteric right region [ maximum standardized uptake value ( suv max ) 10.5 ] , right jugular nodes , right submandibular nodes ( suv max 6.6 ) , and right cervical nodes ( suv max 6.7 ) .
surgical treatment was proposed to the patient , and he gave written informed consent for treatment and case report publication .
thus , the patient was treated surgically by removal of the masseteric mass and by modified radical ipsilateral neck dissection . during surgery ,
the tumor appeared irregularly limited and it was strongly adherent to the mandibular bone surface and the masseter , with a colliquative lower pole .
histological examination identified alveolar rms in the right masseter mass and 44 cervical nodes ( superficial periparotid node , intraparotid node , and levels iia iib iii iv v right cervical nodes ) , with small and intermediate - sized round tumor cells according to hematoxylin and eosin stain ( fig .
the tumor was classified according to the intergroup rhabdomyosarcoma study ( irs ) postsurgical pathological system as group iia ( table 1 ) .
the patient received radiochemotherapy with radiation at 45 gy , while chemotherapy consisted of 14 cycles of vincristine , dactinomycin , and cyclophosphamide ( vac ) .
he was free of locoregional disease with no evidence of distant metastasis 1 year after diagnosis .
a masseter mass associated with an ipsilateral lymphadenopathy may be diagnosed as an infectious disease ( e.g. epidemic parotitis or cat scratch disease ) or a malignant neoplasm , such as non - hodgkin 's lymphoma or sarcoma .
rmss are malignant tumors with a mesenchymal origin , which arise from cells committed to a skeletal muscle lineage that initiate myogenic differentiation but fail to disconnect from their proliferative cycle .
they are related to somatic development alterations , which might explain the high likelihood of these tumors in children . a recent data collection by the surveillance epidemiology and end result ( seer ) registry found that one third of head and neck rmss affected adults ( 2055 years , 23.1% ; > 55 years , 8.1% ) with no gender bias , where the main localization was a parameningeal site with the embryonal histological subtype .
la quaglia et al . reported data from a combined pediatric and adult rms database , where they found that 14.6% of rmss affected patients older than 30 years of age and were typically localized in the extremities , while the head and neck region accounted for only 18% of all adult rmss .
hawkins et al . evaluated data from 84 adult rmss and identified the head and neck region and extremities as the most frequent sites , accounting for 24 and 22% of tumors , respectively .
embryonal was the most common histological subtype ( 53% ) , followed by alveolar ( 30% ) .
little et al . reported data on 82 adult rmss and identified the head and neck region as the most common site ( 52% ) , while most rmss belonged to the pleomorphic and embryonal histological subtypes .
literature case series are heterogeneous , with few studies distinguishing adult data from child data , and they do not divide head and neck case series according to the site . the alveolar subtype has the worst prognosis because of its great propensity for lymph node metastasis .
turner and richmon reported 24% alveolar subtype rmss in the head and neck region , and there was a significant survival difference between the alveolar and embryonal subtypes ( 44.1 and 72.2% at 5 years , respectively ) .
reported that 32% belonged to the alveolar subtype in an adult rms series , and 32% affected the head and neck region .
little et al . reported that 23% belonged to the alveolar subtype of tumors in an adult rms series , while 63% were locally extended at diagnosis .
little et al . confirmed that the therapeutic goal is typically complete surgical excision followed by chemoradiotherapy . in their series , 45% of rmss
, half of which were located in the head and neck region , were not surgically removable .
they confirmed that regional treatment should be included in the overall treatment strategy for the alveolar rms subtype because of its higher incidence of lymphatic metastasis .
systemic chemotherapy , based on dactinomycin or doxorubicin combined with vincristine and cyclophosphamide , was provided to 71% of patients .
there was a median survival time of 38 months for all adult patients , with a 10-year actuarial disease and overall survival rate of 41 and 40% , respectively .
moreover , patients that responded to chemotherapy had a longer metastasis - free period ( 72% at 10 years ) than nonresponders ( 19% at 10 years ) .
raney et al . reported data from the irs group iii and iv protocols in patients younger than 21 years and identified 5 masseter rmss ( 10.6% ) , of which only 1 was an alveolar rms .
reported a case of embryonal rms in a 12-year - old girl affected by bilateral retinoblastoma .
toranzo - fernandez et al . reported a case of alveolar masseter rms in a child , while reynard and brinkley reported an alveolar masseter rms in a 16-year - old boy .
all reported masseter rmss were treated by surgical removal followed by chemoradiotherapy with a poor prognosis , and most patients died after locoregional recurrence .
this is the first case of a masseter alveolar rms reported in literature in an italian patient older than 25 years .
this case highlights the broad spectrum of neoplasms causing parotid region swellings and the importance of considering rare tumors during differential diagnosis .
Output:
| backgroundrhabdomyosarcomas ( rmss ) are a group of soft - tissue malignant tumors which derive from primitive skeletal muscle tissue that mainly affect children and adolescents .
rmss are very rare in adults , where they are usually located in the extremities.case presentationa previously healthy 32-year - old male presented at our ent ( ear , nose and throat ) outpatient clinic after experiencing a parotid region swelling for 2 months .
the patient was treated surgically by excising the mass and by modified radical ipsilateral neck dissection .
histological and immunohistochemical examination indicated masseteric alveolar rms with lymphatic metastasis .
the patient received radiochemotherapy , and he is still alive with no evidence of disease spread 1 year after diagnosis.conclusionthis is the first case of a masseter alveolar rms to be reported in the literature in a patient older than 25 years ; it highlights the broad spectrum of neoplasms that cause parotid region swellings and the importance of considering rare tumors during differential diagnosis . |
PubmedSumm118754 | ***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: to estimate and compare serum cortisol levels in periodontally diseased patients and periodontally healthy individuals .
to compare serum cortisol levels between chronic periodontitis and healthy controlsto compare serum cortisol levels between aggressive periodontitis and healthy controlsto correlate the serum cortisol levels with the clinical parameters within the groups .
to compare serum cortisol levels between chronic periodontitis and healthy controls to compare serum cortisol levels between aggressive periodontitis and healthy controls to correlate the serum cortisol levels with the clinical parameters within the groups
a total of 45 subjects in the age group of 2050 years were recruited for this study .
patients were grouped into chronic and aggressive periodontitis group based on the criteria of aap 1999 .
group i - chronic periodontitis patients ( n = 15)group ii - aggressive periodontitis patients ( n = 15)group iii - healthy controls ( n = 15 ) .
group i - chronic periodontitis patients ( n = 15 ) group ii - aggressive periodontitis patients ( n = 15 ) group iii - healthy controls ( n = 15 ) .
smokersany periodontal treatment within past 6 monthssubjects taking any medicationsystemically ill subjectspregnant or lactating subjects .
any periodontal treatment within past 6 months subjects taking any medication systemically ill subjects pregnant or lactating subjects . institutional ethical committee approval was obtained .
all the patients were instructed the course of study and informed consent was obtained from all patients prior to the start of the study .
the following periodontal parameters were recorded :
plaque indexgingival index ( gi)pocket probing depth in mmgingival recession in mmclinical attachment level in mm was recorded in six sites of all teeth .
gingival index ( gi ) pocket probing depth in mm gingival recession in mm clinical attachment level in mm was recorded in six sites of all teeth .
three milliliter of blood samples were taken from each group from the cephalic vein between 9 am and 11 am .
after collection of blood , serum was decanted and stored at 80 and sent for cortisol analysis which was done using cortisol immunoassay kit .
the mean , median , and standard deviation of the clinical parameters and of blood serum values were determined for each patient group and for controls .
comparison between the serum cortisol levels and clinical parameters was done by nonparametric t - test ( kruskal wallis test ) .
correlation between serum cortisol levels and clinical parameters were done by spearman 's rank correlation coefficient .
significance levels with respect to serum cortisol levels and age , clinical parameters were determined by chi - square test .
smokersany periodontal treatment within past 6 monthssubjects taking any medicationsystemically ill subjectspregnant or lactating subjects .
any periodontal treatment within past 6 months subjects taking any medication systemically ill subjects pregnant or lactating subjects . institutional ethical committee approval was obtained .
all the patients were instructed the course of study and informed consent was obtained from all patients prior to the start of the study .
the following periodontal parameters were recorded :
plaque indexgingival index ( gi)pocket probing depth in mmgingival recession in mmclinical attachment level in mm was recorded in six sites of all teeth .
gingival index ( gi ) pocket probing depth in mm gingival recession in mm clinical attachment level in mm was recorded in six sites of all teeth .
three milliliter of blood samples were taken from each group from the cephalic vein between 9 am and 11 am .
after collection of blood , serum was decanted and stored at 80 and sent for cortisol analysis which was done using cortisol immunoassay kit .
the mean , median , and standard deviation of the clinical parameters and of blood serum values were determined for each patient group and for controls .
comparison between the serum cortisol levels and clinical parameters was done by nonparametric t - test ( kruskal wallis test ) .
correlation between serum cortisol levels and clinical parameters were done by spearman 's rank correlation coefficient .
significance levels with respect to serum cortisol levels and age , clinical parameters were determined by chi - square test .
the mean cortisol values were higher in group i ( 11.750 3.534 ) compared to other groups [ table 1 ] .
on comparison of mean cortisol levels among the groups , the values were statistically significant between group - i and group - iii [ table 2 ] .
comparison of mean serum cortisol levels comparison of mean cortisol levels between the groups group - i showed a statistically significant negative correlation between cortisol levels and gi and positive correlation between cortisol levels and other clinical parameters [ table 3 ] . in group - ii
, a negative correlation was seen between serum cortisol and gi but was not statistically significant .
a positive correlation was found between cortisol and other clinical parameters [ table 4 ] .
correlation between serum cortisol levels and clinical parameters ( group i ) correlation between serum cortisol levels and clinical parameters ( group ii )
a relationship between periodontitis and psychosocial stress was proposed by many investigators over the years , but its relation with regard to the psycho - neuro - immunologic mechanism is poorly understood because of limited information . in the present study , mean serum cortisol levels were higher in chronic periodontitis group compared to healthy controls .
this result is in agreement with the study done by genco et al . in which the mean cortisol levels were higher in group of patients with the disease .
serum cortisol levels showed a negative correlation with the gi which can be explained by the anti - inflammatory effect of cortisol .
furthermore , a positive correlation was found between serum cortisol levels and other clinical parameters in the disease groups .
the impact of stress on the periodontium can be demonstrated by two models : ( 1 ) behavioral model ( 2 ) biological model .
behavioral model explains the influence of health impairing behaviors including poor oral hygiene , increased consumption of cigarettes , alcohol , disturbed sleeping patterns , poor nutritional intake .
biological model suggests that the stress effects may be biologically mediated through the activation of hpa axis , promoting the release of corticotrophin releasing hormone from the hypothalamus and cortisol from the adrenal cortex .
cortisol is an important glucocorticoid hormone released via activation of hpa axis is important due its ability to regulate the recruitment of immune cells in to inflamed tissues as well as to skew the th1/th2 balance toward a th2 dominant response responsible for progressive periodontal disease .
factors influencing cortisol production are age , gender , socioeconomic status , life events , marital status , smoking . on adjusting for the possible confounders
, there was no correlation found for the above factors with the serum cortisol levels . in our present study ,
mean cortisol levels were higher in the chronic periodontitis group compared to aggressive and healthy group , even though , the values were within the reference range .
this variation in the levels is explained by the alteration in the cytokine levels thus activating the hpa through negative feedback loop ( brain - neuro - endocrine immune interaction ) .
this finding is in line with the study done by harbuz et al . which showed no correlation but explained the influence of cytokines levels on the alteration of hpa axis .
however , monteiro da silva et al . found no correlation between psychological stress and periodontal disease .
he studied the psychological status in 40 patients with chronic and aggressive periodontitis each and found no association between psychological factor and periodontal disease . in the present study
, the presence of significant difference in the serum cortisol levels between the disease group and control group explains the influence of stress factor on the periodontal status .
however , the difference in the serum cortisol levels between the chronic group and aggressive group is less significant which may be attributed to the small sample size selected for the study and the larger sample size would provide better conceptual evidence .
however , many longitudinal studies are necessary in the periodontal epidemiology area to evaluate the role of social support and stress coping strategies together with the psychosocial / physiological stress , on the establishment and progression of periodontitis .
within the limits of the study serum cortisol levels were higher in the chronic periodontitis group compared to the other groups .
positive correlation was found between the cortisol levels and other clinical parameters except for the gi .
Output:
| introduction : psychological conditions , particularly psychosocial stress have been implicated as risk indicators of periodontal disease .
stress increases cortisol production from the adrenal cortex by stimulating an increase in the release of acth from the pituitary gland .
increased cortisol production suppresses the immune response and increases the potential of periodontal tissue destruction.aim:the aim of the present study was to estimate and compare the serum cortisol levels in periodontally diseased patients and periodontally healthy individuals.materials and methods : total of 45 subjects were recruited for this study and were categorized into three groups .
group i - comprised of aggressive periodontitis patients ( n = 15 ) , group ii - chronic periodontitis patients ( n = 15 ) , and group iii - healthy controls ( n = 15 ) .
serum samples were collected from each of the groups and cortisol levels were determined using cortisol immunoassay kit . clinical examination covered probing depth , gingival index ( gi ) , gingival recession , plaque index , and clinical attachment level .
the statistical analysis was done using nonparameteric t - test and spearman 's rank correlation coefficient.results:with respect to cortisol , the levels were higher in group - i compared to the other groups .
on comparison of mean cortisol levels among the groups , the values were statistically significant between group - i and group - iii .
group - i showed a significant negative correlation between cortisol levels and gi.conclusion:within the limits of the study serum cortisol levels was higher in the chronic periodontitis group compared to the other groups .
positive correlation was found between the cortisol levels and other clinical parameters except for the gi . |
PubmedSumm118755 | ***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 most common clinical presentation of patients with lupus anticoagulant antibody is arterial or venous thromboembolism1 ) .
hemorrhage is much less common and this is usually attributable to the associated thrombocytopenia , a platelet dysfunction , a prothrombin deficiency or other underlying coagulopathies2 , 3 ) .
, steroid is required to treat patients ' hemorrhages , and steroid has been noted to promptly correct the hypoprothrombinemia and control bleeding events4 ) .
he was referred to our hospital because of his prolonged coagulation time , which was discovered during his lab work - up for an orthopedic operation .
the laboratory studies showed lahps with microscopic hematuria ; however , any viral infection or other systemic disease was not found .
a 34-year - old - man was admitted to another hospital for an orthopedic operation .
the coagulation studies showed a prolonged prothrombin time ( pt ) and an activated partial thromboplastin time ( aptt ) .
he was not taking any medication , and especially , any anticoagulant and antiplatelet agents .
the initial laboratory tests showed a leukocyte count of 8,200/mm , a hemoglobin of 14.7 g / dl and a platelet count of 226,000/mm .
the pt was 15.2 sec ( normal values ( nv ) : 10.0 - 13.0 sec ) , the aptt was 37.7sec ( nv : 27.5 - 34.7 sec ) .
evaluation of the clotting factors revealed decreased levels of factors ii , v , viii , ix and xi ( table 1 ) .
a 1:1 dilution of patient plasma with normal plasma nearly corrected the pt , but this failed to correct the aptt . the diluted russell 's viper venom time ( drvvt , american diagnostica , ) was positive .
the tests for antinuclear antibodies and anti double stranded dna antibodies were negative ; the c3 and c4 complement levels were low .
the patient denied any symptoms that would be suggestive of sle , and there was no family history of bleeding or connective tissue disease .
an extensive infectious disease workup ruled out hepatitis a , b and c , cytomegalovirus and epstein barr virus .
finally , we diagnosed the patient as having lupus anticoagulant - hypoprothrombinemia ( lahps ) .
however , he displayed only microscopic hematuria and he was without sle or any underlying disease .
so , we closely followed the patient 's laboratory findings and clinical symptoms for 2 months .
he did not show any symptoms or signs of bleeding , yet the abnormal laboratory findings were sustained .
we decided to try corticosteroid treatment to prepare the patient for orthopedic surgery and then 2 weeks later , the coagulation studies were significantly improved .
he successfully underwent the operation and was discharged . at present , he hasn't any symptoms or signs of thrombosis , hemorrhage and sle .
lupus anticoagulant ( la ) is an antiphospholipid antibody that causes prolonged in vitro coagulation times .
a bleeding diathesis is a rare manifestation of lupus anticoagulant , and when it occurs , it was nearly always due to thrombocytopenia or factor ii deficiency2 , 3 ) . lupus anticoagulant hypoprothrombinemia syndrome ( lahps ) is a rare clinical malady that can occur in association with sle , transient viral infections , drug reactions or even in healthy individuals5 , 6 ) .
it mostly occurs in young females , and only rarely in those adults who are without systemic lupus erythematosus , an underlying disease or a preceding illness2 ) .
the clinical findings are generally asymptomatic , but there can be severe hemorrhagic symptoms such as brain hemorrhage , gastrointestinal bleeding and diffuse muscular hemorrhage . these patients may present with severe life threatening bleeding diathesis if the factor ii level is very low ( i.e. , usually under 10%)2 ) .
in our case , the factor ii level was 29% and only microscopic hematuria was observed .
have reported on a case of lahps for which the patient did not respond to replacement therapy , and the patient showed a significant response to immunosuppressive drugs7 ) .
most of the cases previously reported in the literature have responded well to administering only prednisone treatment4 ) .
a few cases needed an additional immunosuppressive drug such as cyclophosphamide or azathioprine7 , 8) .
corticosteroid therapy is the treatment of choice for lahps associated with sle ; it normalizes the abnormal coagulation times , including the pt , the aptt and the clotting factors . for those cases associated with viral infection ,
the lahps spontaneously reverses itself when the infection has been resolved , and so steroid therapy is not necessary .
therefore , we followed up the laboratory findings and clinical symptoms for 2 months ; during this time , he did not display any symptoms and signs of bleeding .
we decided to institute corticosteroid treatment for getting him ready for orthopedic surgery ; 2 weeks later , the coagulation studies were significantly improved .
prompt , close follow up of these patients is crucial because they may develop , at any time , the full clinical syndrome of sle and thrombosis because of the presence of la .
Output:
| the presence of lupus anticoagulant is associated with an elevated risk of venous and arterial thrombosis , and recurrent miscarriages as well .
for some cases , this disease can present with bleeding as a consequence of lupus anticoagulant hypoprothrombinemia ( lahps ) .
lahps is a rare disease and it is reported to be most frequent in young females with / without systemic lupus erythematosus or in healthy children who are suffering with a viral infection . in such cases , steroid therapy is usually effective in normalizing the biological abnormalities and controlling the bleeding problems.a 34-year - old previously healthy man was admitted to our department because of his prolonged coagulation times ; these abnormalities were discovered before performing orthopedic surgery .
the prothrombin time ( pt ) was 15.2 sec , and the activated partial thromboplastin time ( aptt ) was 37.7 sec .
a 1:1 dilution of patient plasma with normal plasma nearly corrected the pt , but this failed to correct the aptt .
evaluation of the clotting factors revealed decreased levels of factors ii , v , viii , ix and xi .
the presence of la was demonstrated by the drvvt test , and the patient was diagnosed with lahps . he was successfully treated with corticosteroid before performing the orthopedic surgery . |
PubmedSumm118756 | ***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: colorectal cancer represents the second leading cause of cancer - related deaths due to therapy resistance both in europe and united states . drug resistance is thought to cause treatment failure in over 90% of patients with metastatic cancer , while drug resistant micrometastic tumour cells may also reduce the impact of adjuvant chemotherapy treatment .
drug resistance , underlying tumour recurrence and the lack of curative treatments in metastatic disease , raises the question whether conventional anticancer therapies target the right cells . indeed , these treatments might miss circulating tumour cells ( ctcs ) , and particularly the chemoresistant and radioresistant subpopulation within them .
recent evidences suggest that the count of ctcs has prognostic significance in metastatic colorectal cancer , as well as in other epithelial malignancies .
it has been suggested that more aggressive ctcs share genotypic characteristics with cancer stem cells , characterized by multidrug resistance , which allow these cells to drive tumour growth evading apoptosis and conventional therapy . in colorectal cancer , specifically , cd44 , cd133 and aldheyde dehydrogenase 1 ( aldh1 ) have been recently suggested as potential markers of colorectal cancer stemness .
apoptosis evasion through the overexpression of survivin also represents one of the mechanisms by which tumour cells acquire the ability to enter into the blood flow and escape to drug - induced death . in colon cancer ,
specifically , the induction of survivin signalling pathway represents one mechanism of resistance to oxaliplatin ( l - ohp ) and 5-fluoruracil ( 5-fu ) by modulating caspase - dependent and caspase - independent apoptosis .
furthermore , the expression of multidrug resistance related protein 5 ( mrp5 ) , belonging to atp binding cassette transporters family , is associated to resistance to 5-fu and platin compounds . in a previous study , we demonstrated that a drug resistance profile on ctcs from epithelial cancers through the evaluation of specific mrps is predictive of resistance to chemotherapy , independently of tumour type and stage of disease [ 6 , 7 ] .
we thus investigated the prognostic significance of drug resistance and stemness markers in ctcs isolated from metastatic colorectal cancer patients treated with l - ohp and 5-fu based regimens .
forty ( 40 ) patients with metastatic colorectal cancer were enrolled between october 2007 and october 2009 at sapienza university of rome .
inclusion criteria were measurable metastatic colorectal cancer , commencement of a new systemic therapy with 5-fu and l - ohp , with eastern cooperative oncology group performance status score of 0 to 2 .
ctcs were isolated from 10 cc of peripheral blood by cellection dynabeads coated with the monoclonal antibody towards the human epithelial cell adhesion molecule . from the isolated ctcs cdnas
were synthesised and subjected to pcr amplifications specific for cea ( used as a marker for colorectal cancer cells ) aldh1 , cd44 , cd133 ( used as markers of stemness ) , mrp5 ( used as marker of resistance to 5-fu and l - ohp ) and survivin ( used as a marker of apoptosis resistance ) .
statistical analysis was performed with bmdp statistical software , version 7 ( statistical solutions , saugus , ma , usa ) and spss ( chicago , version 15.00 for windows ) .
progression - free survival ( pfs ) was defined as the time elapsed between the date of blood sampling , corresponding to the start of treatment and the date of clinical disease progression or death for any cause .
meier product - limit method was used to correlate pfs with expression of survivin , mrp5 , aldh1 , cd133 and cd44 .
twenty - seven of 40 ( 67% ) patients were found positive for the presence of ctcs . in the group of ctc patients , 12/27 ( 45% ) had progression of disease ( pd ) and 15/27 ( 55% ) had a clinical response ( cr ) during the time course of chemotherapy with l - ohp and 5-fu based regimens .
an amplification reaction with cea primers was performed on rnas extracted from ctc patients ; all 27 samples were found positive .
aldh1 ctcs were detected in 9 ( 33% ) out of 27 ctc patients . among these aldh1 patients ,
a significant correlation between aldh1 expression and poor outcome ( p 0.046 ) was found ( fig .
cd44 and cd133 ctcs were found in 3/27 ( 11% ) and 2/27 ( 7% ) patients , respectively .
no correlation was found between expression of either cd44 and cd133 or outcome of patients ( p 0.8 for both ) .
survivin was detected in ctcs from 13/27 ( 48% ) patients . in the group of survivin
positive patients , 10/13 ( 77% ) had pd and 3/13 ( 23% ) had cr . in the group of 14 survivin negative patients , pd was observed in 2/14 ( 14% ) of cases , and cr in 12/14 ( 86% ) . the difference in pfs between the two groups
mrp5 , which transports l - ohp and 5-fu , was found expressed in ctcs from 15/27 patients ( 55% ) . among these patients ,
mrp5 patients had a significantly shorter pfs compared to patients whose ctcs were negative for mrp5 expression ( p < 0.001 ) ( fig .
2 , rt - pcr amplification products for all genes examined in ctcs from four exemplificative patients are shown .
the expression of all markers analysed on ctcs in the population with and without drug resistance is shown in table 1 .
meier curves showing the difference in pfs between patients with ctcs positive and negative for aldh1 ( a ) , survivin ( b ) and mrp5 ( c ) expression .
cea , cd133 , cd44 , aldh-1 , mrp5 and survivin rt - pcr amplification products obtained by ctcs isolated from four colorectal cancer patients ( lanes 14 ) loaded on 2% agarose gel ; + , positive control ; , negative control ( sample without rna ) ; m , molecular weight marker .
the expression of cd44 , cd133 , aldh1 , survivin and mrp5 in a population with and without resistance to chemotherapy is shown . in the same population response to therapy ( pd = progressive disease ; cr = clinical response ) and pfs in months are indicated .
recent in vitro studies suggest that survivin expression represents a significant and independent predictor of resistance to l - ohp and 5-fu .
consistently with this observation , we describe for the first time that expression of survivin is a significant indicator of poor response to 5-fu and l - ohp in ctcs from metastatic colorectal cancer patients .
thus , the first conclusion is that the detection of survivin - positive ctcs may be predictive of poor response to chemotherapy in metastatic colorectal cancer . in a similar manner , patients whose ctcs express mrp5 had a shorter pfs and higher progression rate when treated with 5-fu and l - ohp specific mrp5 substrates .
preliminary data obtained in vitro have suggested that survivin plays a role in the chemoresistance mediated by p - glicoprotein ( pgp ) in breast cancer cells by modulating the turnover of pgp or transport by pgp in the cell , which then results in anti - apoptosis and drug resistance .
furthermore , the association between survivin and pgp has been correlated to poor prognosis of patients . in our series a similar concomitant expression of survivin and mrp5 was found in ctcs from 13/15 ( 87% ) patients , all characterized by early progression of disease ; we thus suggest that the expression of survivin may directly interfere with mrp5 mediated drug resistance , resulting in chemotherapy failure .
in addition , it has been demonstrated that drug resistance is often associated with aldh1 expression in several cancer tissues ; thus it was expected that aldh1 would be associated with poor prognosis due to chemotherapy inefficiency .
corresponding experimental results for ctcs are still outstanding , except for breast cancer , where it has been recently demonstrated that the expression of aldh1 among ctcs is associated with therapy failure . to date , no similar data on ctcs have been reported for colorectal cancer . in conclusion
, these results may suggest that isolating survivin and mrp5 expressing ctcs may help in the selection of metastatic colorectal cancer patients resistant to 5-fu and l - ohp , for which alternative chemotherapy regimens may be appropriate .
this addresses the important question whether ctcs can guide therapy choice and whether molecular analyses of these cells can aid in patient selection for targeted agents .
Output:
| abstractthe prognosis of metastatic cancer patients is still largely affected by treatment failure , mainly due to drug resistance .
the hypothesis that chemotherapy might miss circulating tumour cells ( ctcs ) and particularly a subpopulation of more aggressive , stem - like ctcs , characterized by multidrug resistance , has been recently raised .
we investigated the prognostic value of drug resistance and stemness markers in ctcs from metastatic colorectal cancer patients treated with oxaliplatin ( l - ohp ) and 5-fluoruracil ( 5-fu ) based regimens .
forty patients with metastatic colorectal cancer were enrolled .
ctcs were isolated from peripheral blood and analysed for the expression of aldheyde dehydrogenase 1 ( aldh1 ) , cd44 , cd133 ( used as markers of stemness ) , multidrug resistance related protein 5 ( mrp5 used as marker of resistance to 5-fu and l - ohp ) and survivin ( used as a marker of apoptosis resistance ) .
ctcs were found in 27/40 ( 67% ) patients .
no correlation was found between the expression of either cd44 and cd133 in ctcs and the outcome of patients , while a statistically significant shorter progression - free survival was found in patients with ctcs positive for the expression of aldh1 , survivin and mrp5 .
these results support the idea that isolating survivin and mrp5 + ctcs may help in the selection of metastatic colorectal cancer patients resistant to standard 5-fu and l - ohp based chemotherapy , for which alternative regimens may be appropriate . |
PubmedSumm118757 | ***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: when confronted with the title what is new in surgical treatment of vesicoureteric reflux ? many readers will automatically think of endoscopic techniques with subureteric injection of bulking agents , also known as sting ( subureteral teflon injection ) . over the years
several substances have been advocated as bulking agents , but the original teflon is no longer in use .
( the most commonly used substance nowadays is deflux , a dextranomer / hyaluronic acid copolymer . )
however , a technique that has been around for a quarter of a century can hardly be considered for a text on surgical novelties .
vesicoureteric reflux ( vur ) remains one of the most frequent conditions in paediatric urology , although the exact prevalence is largely unknown .
vur can be primary , secondary ( e.g. to elevated bladder pressures in neurogenic bladders or dysfunctional voiding ) and sometimes intermittent in nature , only disclosing itself when infection has possibly induced a degree of insufficiency of the ureterovesical junction .
it is generally assumed that vur predisposes to urinary tract infections and that surgical treatment of reflux and prophylactic antibiotics are equivalent in terms of preventing infections and renal scarring .
the relative merit of these interventions in the natural course of these conditions remains to some extent controversial .
the importance of voiding dysfunction with detrusor overactivity , underactivity or dysfunctional elimination disorder in the aetiology of vur should not be underestimated [ 4 , 30 ] and this has its implications in the treatment offered to these children . hence bladder training and minimally invasive techniques
children with vur and concomitant voiding dysfunction are likely to suffer more breakthrough infections and have lower spontaneous resolution rates and therefore represent a large proportion of the patients undergoing surgical intervention .
antimicrobials form the mainstay in the treatment of vur , in combination with other conservative measures , because vur will spontaneously disappear in a majority of children and rarely gives rise to serious long - term complications . increasingly however
the exact role of prophylaxis is being questioned as well - designed prospective trials are rare .
nevertheless , a small subgroup of patients does pose problems of break - through infections despite all conservative measures and in fact some of them seem prone to renal scarring leading to hypertension and exceptionally even end stage renal failure .
all techniques share the same basic principle of creating an anti - reflux mechanism by increasing the portion of the distal ureter lying in a submucosal tunnel between the detrusor muscle and the bladder mucosa .
they offer comparable and very high success rates with few complications . from a purely technical standpoint
there are those that involve mainly or entirely intravesical ureteral dissection ( and hence a need for postoperative bladder drainage ) and those that use a purely extravesical approach to the ureter without disconnecting it from the bladder .
to the former group belong the techniques of politano and leadbetter ( 1958 ) , glenn and anderson ( 1967 ) , the psoas - hitch technique and the ( most widely used ) cohen technique ( 1975 ) [ 6 , 11 , 13 , 25 ] . in these techniques
the ureter is disconnected from the bladder and reimplanted in a new and longer submucosal tunnel from the luminal side of the bladder . in the cohen technique ,
a cross - trigonal tunnel is created bringing the ureter to the contralateral side , the other techniques result in a more natural course of the ureter , but are somewhat more prone to complications such as bowel injury or kinking of the ureter .
the psoas - hitch technique is generally reserved for more complex situations as in mega - ureters or re - do surgery and is helpful in creating a longer tunnel .
the conceptually different extravesical approach was popularized by lich and gregoir , reducing postoperative bladder irritation to insignificance , but predisposing to temporary bladder retention when performed bilaterally [ 14 , 21 ] .
the more recent and certainly minimally invasive sting technique where bulking agents are injected submucosally has gained wide acceptance .
undoubtedly this is technically a very easy , relatively cheap and patient - friendly treatment modality , tempting many doctors into an increasingly pre - emptive approach to vur , using it as first - line treatment in cases of ( antenatally detected ) high - grade reflux even in infants .
success rates , even in low - grade reflux , are clearly lower than in open surgery and a second injection of bulking agent is often necessary
. moreover , prospective randomised trials and long - term results are still not available .
the tendency to use this endoscopic technique as an alternative to medical treatment is underscored by the fact that since the food and drug administration ( fda ) approval of deflux the total number of procedures for reflux has increased , while open surgery rates have remained stable .
all these facts and tendencies mentioned above in turn suggest that , at least for the foreseeable future , there will remain a group of patients in whom sting is deemed - or proves to be - insufficient .
open surgery on the other hand has its drawbacks as well due to its invasiveness . in an ideal world physicians
would be able to define very precisely and at the earliest possible point in time which group of patients with vur is at increased risk for the complication of pyelonephritic scarring and which group is not .
this would in turn allow a very tailored approach to each individual child with pre - emptive surgical measures in the group at risk .
failing this knowledge , the next best thing to aim for is to combine the superior results of time - honoured open procedures like a cohen reimplantation or lich - gregoir operation with the much sought after minimal invasiveness of laparoscopy , possibly with the added ultra - precise tissue handling and dexterity of robotic surgery .
both intra- and extravesical laparoscopic treatments have been described in a great variety of techniques .
were the first to report in 1994 and 1995 on two and six children undergoing laparoscopic lich - gregoir anti - reflux surgery for vesicoureteral reflux [ 7 , 17 ] .
described decreased peri- and post - operative pain and improved cosmesis by comparison with open surgery .
the other hand concluded that the lich - gregoir anti - reflux procedure was a complicated one because of the difficult suturing and knot - tying , offering no clear advantage over the conventional procedure .
other teams were very reluctant to join in the efforts to develop this approach for several years to come .
the choice for a lich - gregoir technique for the first attempts at correction of vur can be explained by the fact that , at that time , experience with laparoscopy in cavities other than the abdomen was very limited .
five years later lakshmanan and fung reported technical modifications to further minimize invasiveness , basically by downsizing ports and instruments and limiting tissue dissection . a more recent paper by riquelme et al .
again reported excellent outcomes in 15 children , even in cases of bilateral reflux and duplex ureters .
laparoscopic ureteral reimplantation with extracorporeal tailoring and stenting of megaureters combined with a lich - gregoir type of extravesical reimplantation was recently reported by ansari et al . in three children .
although the cohen procedure was the more widely used in the treatment of vur , a laparoscopic version thereof was investigated later than the extravesical laparoscopic techniques .
the obvious reason is the anticipated difficulties with port placement and the limitations of the intravesical working space .
gill et al . combined the use of two suprapubic ports with a transurethral resectoscope for unilateral cases whereas yeung et al .
a recent report by kutikov et al . on either transvesical laparoscopic cross - trigonal ureteral reimplantation in patients with reflux or a glenn - anderson reimplantation in patients with a primary obstructing mega - ureter mentions operative success in 25 of 27 patients with vur and 4 out of 5 patients with mega - ureters , results that are comparable to the ones obtained in open surgery .
complications were postoperative urinary leak in four patients and ureteral stricture at the anastomosis in two .
the authors noted that most complications occurred in the younger patients with small bladder capacities . for completeness two papers on reimplantations in ( young ) adults can be mentioned .
chung et al . described successful laparoscopic nonrefluxing ureteral reimplantation with a psoas hitch using a submucosal tunnelling technique after submucosal injection of saline under cystoscopy in two adult female patients without postoperative complications .
described laparoscopic extravesical ureteroneocystostomy with psoas hitch in five gynaecologic patients , clearly minimizing the procedural morbidity . again no intraoperative or postoperative complications occurred .
gradually more relevant series with larger numbers of patients and longer follow - up are being presented . at the 2007 european society for paediatric urology ( espu ) annual meeting two groups will present their experience in about 80 patients each , with success rates above 90% ( http://www.espu.org ) .
over the last 2 years a few authors reported robot - assisted laparoscopic techniques using the da vinci ( intuitive surgical , mountain view , ca ) system for the treatment of vur , adding yet another approach to this rapidly expanding field [ 3 , 23 , 24 ] .
they made good use of the experience gained with conventional laparoscopy , adding the advantages of robotics : enhanced dexterity of the instruments , absence of tremor and 3-d vision .
the generally used term of robotic surgery is to some extent actually misleading because it suggests completely autonomous function of the equipment . in reality
it works as a master - slave system , merely transferring the movements of the surgeon s hands to the tip of the instruments ( fig . 1 ) .
the evolution parallels the one seen in conventional laparoscopy , experience having started with the extravesical approach and later moving to intravesical procedures .
as stated , they closely mirror the steps in conventional laparoscopy .
fig .
1outside view once the draped robotic arms are connected to the laparoscopic ports : the child seems completely embraced by the machine outside view once the draped robotic arms are connected to the laparoscopic ports : the child seems completely embraced by the machine to start , a cystoscopic evaluation of the relevant anatomy is carried out .
the camera port is then placed in the umbilicus and the two working ports in each lower abdominal quadrant .
a small transverse peritoneal incision is made on the laterodorsal side of the bladder where the ureter is retrieved .
the ureter is then buried in a trough between the mucosa and detrusor to create the anti - reflux mechanism ( figs . 2 and 3 ) .
the bladder catheter is removed already at the end of the procedure unless a significant perforation needing suturing of the mucosa has been made .
2extravesical approach : very gently the detrusor muscle is incised and peeled away until the delicate bladder mucosa starts to bulgefig .
3extravesical approach : the completely freed ureter is hinged into the trough to create an anti - reflux valve mechanism extravesical approach : very gently the detrusor muscle is incised and peeled away until the delicate bladder mucosa starts to bulge extravesical approach : the completely freed ureter is hinged into the trough to create an anti - reflux valve mechanism in our experience there were no bladder symptoms post surgery in any of the patients .
all cases of reflux resolved , but there was one case of de novo contralateral low - grade reflux .
later we successfully performed this operation in an adult male patient after a failed subureteral injection ( unpublished data ) .
recently reported on the use of the open lich - gregoir technique as salvage in these patients as well and already in 2004 one similar laparoscopic patient was reported by shu et al . . both in open and laparoscopic surgery this was a novel approach , meant to avoid the sometimes difficult intravesical dissection due to foreign material after sting .
peters and borer reported persisting low - grade reflux in 2 of their 24 patients .
olsen was the first to experiment with a cohen cross - trigonal ureter reimplantation by laparoscopic access to the bladder in a pig model using the da vinci system .
the advantage of the robotic equipment seemed to be the better access to submucosal tunnelling of the ureter and the intravesical suturing of the anastomosis .
peters and woo in 2005 and callewaert in 2006 reported their experience with robot - assisted cohen procedures in six and three paediatric patients respectively [ 3 , 24 ] .
initial port placement and closure of the incisions at the end of the procedure were the crucial steps , the rest of the procedure being straightforward .
once inside the bladder the mucosa is circumferentially incised around the ostium using the cautery hook . after both ureters are freed ,
a submucosal tunnel connecting the most proximal part of the two mucosal incisions is created , using forceps and scissors ( fig .
creation of the submucosal tunnel and reimplantation of the ureters is remarkably easy because of the three dimensional visualisation and great dexterity inside the very small volume of a child s bladder .
the anatomical detail is such that dissection of the plane between the detrusor and mucosa is achieved with more detail than in open surgery .
the bladder catheter is left indwelling for 24 to 48 h.
fig .
( the jaws of the forceps measure 5 mm in length ) intravesical approach : creation of the submucosal tunnel connecting the periureteral incisions .
( the jaws of the forceps measure 5 mm in length ) we had one conversion to open surgery out of three cases in our early experience because of port - related problems in a small child .
kutikov et al . using conventional laparoscopy similarly found that the smaller children were more prone to complications and that these procedures were technically more demanding .
peters and woo on the other hand reported no conversions in a series of six children aged between 5 and 15 .
they did however have a case of port - site urinary leakage requiring prolonged bladder drainage .
peters and callewaert each reported one case of persisting low - grade reflux in their initial experience .
unlike the situation in open surgery , bladder spasms remained completely absent and anticholinergics were unnecessary .
this fact is highly suggestive of the minimal invasiveness and limited trauma incurred by the bladder wall . when comparing the robotically assisted intra- and extravesical operations it is our impression that the lich - gregoir technique offers some advantages over the intravesical operation : no need for catheters , no haematuria and easier reproducibility .
the abdominal cavity even in smaller children is large enough to allow comfortable movement of the instruments , whereas intravesical operations in this patient group can be technically impossible due in part to the relative bulkiness of the robotic instruments .
to start , a cystoscopic evaluation of the relevant anatomy is carried out . the camera port is then placed in the umbilicus and the two working ports in each lower abdominal quadrant . a small transverse peritoneal incision is made on the laterodorsal side of the bladder where the ureter is retrieved .
the ureter is then buried in a trough between the mucosa and detrusor to create the anti - reflux mechanism ( figs . 2 and 3 ) .
the bladder catheter is removed already at the end of the procedure unless a significant perforation needing suturing of the mucosa has been made .
2extravesical approach : very gently the detrusor muscle is incised and peeled away until the delicate bladder mucosa starts to bulgefig .
3extravesical approach : the completely freed ureter is hinged into the trough to create an anti - reflux valve mechanism extravesical approach : very gently the detrusor muscle is incised and peeled away until the delicate bladder mucosa starts to bulge extravesical approach : the completely freed ureter is hinged into the trough to create an anti - reflux valve mechanism in our experience there were no bladder symptoms post surgery in any of the patients .
all cases of reflux resolved , but there was one case of de novo contralateral low - grade reflux .
later we successfully performed this operation in an adult male patient after a failed subureteral injection ( unpublished data ) .
interestingly , elmore et al . recently reported on the use of the open lich - gregoir technique as salvage in these patients as well and already in 2004 one similar laparoscopic patient was reported by shu et al . . both in open and laparoscopic surgery this was a novel approach , meant to avoid the sometimes difficult intravesical dissection due to foreign material after sting .
peters and borer reported persisting low - grade reflux in 2 of their 24 patients .
olsen was the first to experiment with a cohen cross - trigonal ureter reimplantation by laparoscopic access to the bladder in a pig model using the da vinci system . in all pigs
the advantage of the robotic equipment seemed to be the better access to submucosal tunnelling of the ureter and the intravesical suturing of the anastomosis .
peters and woo in 2005 and callewaert in 2006 reported their experience with robot - assisted cohen procedures in six and three paediatric patients respectively [ 3 , 24 ] .
initial port placement and closure of the incisions at the end of the procedure were the crucial steps , the rest of the procedure being straightforward .
once inside the bladder the mucosa is circumferentially incised around the ostium using the cautery hook . after both ureters are freed ,
a submucosal tunnel connecting the most proximal part of the two mucosal incisions is created , using forceps and scissors ( fig .
creation of the submucosal tunnel and reimplantation of the ureters is remarkably easy because of the three dimensional visualisation and great dexterity inside the very small volume of a child s bladder .
the anatomical detail is such that dissection of the plane between the detrusor and mucosa is achieved with more detail than in open surgery .
the bladder catheter is left indwelling for 24 to 48 h.
fig .
( the jaws of the forceps measure 5 mm in length ) intravesical approach : creation of the submucosal tunnel connecting the periureteral incisions .
( the jaws of the forceps measure 5 mm in length ) we had one conversion to open surgery out of three cases in our early experience because of port - related problems in a small child .
using conventional laparoscopy similarly found that the smaller children were more prone to complications and that these procedures were technically more demanding .
peters and woo on the other hand reported no conversions in a series of six children aged between 5 and 15 .
they did however have a case of port - site urinary leakage requiring prolonged bladder drainage .
peters and callewaert each reported one case of persisting low - grade reflux in their initial experience .
unlike the situation in open surgery , bladder spasms remained completely absent and anticholinergics were unnecessary .
this fact is highly suggestive of the minimal invasiveness and limited trauma incurred by the bladder wall . when comparing the robotically assisted intra- and extravesical operations it is our impression that the lich - gregoir technique offers some advantages over the intravesical operation : no need for catheters , no haematuria and easier reproducibility .
the abdominal cavity even in smaller children is large enough to allow comfortable movement of the instruments , whereas intravesical operations in this patient group can be technically impossible due in part to the relative bulkiness of the robotic instruments .
conventional or robot - assisted laparoscopic techniques must be considered a possible future alternative to the more traditional ways of treating this condition .
there is no proven superiority at this time and experience is limited to a few centres only and relatively small numbers of patients .
it is well established that with open surgery very high success rates can be achieved and that morbidity is relatively low and hospitalisation nowadays can be kept short .
the first impressions are that morbidity using laparoscopic techniques is lower still and that there is some cosmetic gain , but it is obvious that the most important issue will be whether the long - term success rates are at least comparable .
most surgeons agree that robotics certainly add to the precision and ease of the individual surgical steps when compared to conventional laparoscopy , but the financial costs are very high .
the intravesical approach using robotics is feasible , but technical difficulties must be taken into account in smaller children .
the extravesical robotic approach clearly seems the more promising , possibly even after failed submucosal injection therapy .
nevertheless we feel that the intravesical approach deserves further pursuing because it may allow surgical correction of other malformations at the level of the bladder neck and ureterovesical junction in a minimally invasive and very precise way .
it would be premature to promote laparoscopy as the golden mean between sting and open surgery for a subgroup of reflux patients at this point , as this would imply diverting a large number of patients to a few centres where either the technical laparoscopic expertise or a robotic system is available .
however , we remain convinced that in the ( near ) future laparoscopy will find its place in the care for these patients .
Output:
| in addition to conventional open surgery and endoscopic techniques , laparoscopic correction of vesicoureteric reflux , sometimes even robot - assisted , is becoming an alternative surgical treatment modality for this condition in a number of centres around the world .
at least for a subgroup of patients laparoscopists are trying to develop new techniques in an effort to combine the best of both worlds : the minimal invasiveness of the sting and the same lasting effectiveness as in open surgery .
the efficacy and potential advantages or disadvantages of these techniques are still under investigation .
the different laparoscopic techniques and available data are presented . |
PubmedSumm118758 | ***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 fact that vertical dimension control is one of the most difficult tasks in orthodontic treatment has been recognized for a long time . to thoroughly understand the vertical facial height ( vfh )
vertical dimension , generally speaking , includes anterior ( afh ) and posterior facial height ( pfh ) . according to bjrk
forward mandibular rotation occurs when pfh overdevelops relative to afh ; however , in many literature sources more attention was focused on the afh and lower afh has been confirmed as having a strong influence on the formation of vertical facial disproportions [ 27 , 28 , 34 ] . on the other hand some accepted terminologies used in describing vertical morphology , such as long and short face or dolichofacial and brachyfacial
are mainly based on afh . in the extreme case the short or long face syndrome
is believed to be always characterized by low or high mandibular plane angle , respectively [ 32 , 25 ] .
nanda gave a similar viewpoint in a longitudinal study by differentiating the sample using the presence of anterior open bite or deep bite .
however , in extreme vertical cases , muscle or organ dysfunction , such as nasal obstruction as suggested by vig is always involved .
van spronsen et al . also proposed that musculoskeletal interactions might differ between populations with normal faces and a selected group of individuals with long faces .
therefore , the orthodontic strategy on vertical control could be different between normal and extreme vertical cases .
thus it is important to study the facial height by excluding the extreme case of anterior open bite and deep bite so that the effect played by the muscle or organ dysfunction could be considerably diminished . under the circumstances of anterior
relatively normal overbite , the role played by both afh and pfh in the formation of vertical facial type could become clear . at the same time
it was also planned to verify if it is always true that the steeper the mandibular plane anteriorly inclines , the greater the afh becomes or vice versa .
there is no doubt that longitudinal studies enable facial growth development to be understood more thoroughly than cross - sectional studies .
however , fit is also necessary to know how the adult facial height , including afh and pfh , correlates with mandibular plane angle , facial depth and width as well through the cross - sectional method . to identify such correlations is crucial for fully understanding human craniofacial morphology and the functional interrelationship among the three dimensional ( 3d ) structures so that orthodontic treatment strategies can be more effectively designed . only a few studies , however , have focused on the assessment of the correlations of the 3d craniofacial structures measurements , especially on the linear measurements .
because of the well - known reason of the distortion and magnification of linear measurements in the conventional cephalometric measurements , angle measurements wherever feasible were suggested to be employed .
on the other hand lundstrm et al . evaluated facial depth and height changes by using ratio measurements .
in addition to inaccuracy the traditional two - dimensional ( 2d ) cephalometric analysis was actually based on a combination of lateral and posteroanterior films although it was referred to as a 3d method for several decades [ 6 , 10 , 16 ] . the same landmarks located in lateral and posteroanterior films were not always identical in these traditional studies .
the advent of 3d computed tomography ( ct ) technology allows direct visualization of the entire craniofacial structure instead of combining two projected films .
furthermore , advances in 3d software have led to actual 3d measurements becoming a reality .
it is indubitable that the traditional cephalometry is still a valuable tool that can provide important information when used properly . during the past decade
however , it has been verified many times in the literature that 3d ct , especially 3d cone - beam ct ( cbct ) has shown to be greatly superior to the 2d approach both in the reliability of anatomical landmark identification [ 17 , 7 ] and in measurement accuracy [ 1 , 11 , 23 ] .
therefore , in the present study in order to investigate the craniofacial structure three dimensionally accurately the 3d cbct technique was used to preliminarily evaluate how the vertical facial height correlates with mandibular plane angle , facial width and depth in caucasian dry skulls to deepen the understanding of vertical facial dimension and its functional interrelationships among 3d structures .
the sample consisted of the cbct data from 43 dry skulls which had been previously acquired in the natural history museum of vienna by scanning the dry skulls of the weisbach collection which includes the dry skulls of soldiers of the austrian imperial army who died around 1870 .
archival records show that the skulls mainly belonged to adult males who died between the ages of 19 and 50 years .
the following inclusion criteria were used in this study : no cranial deformities , complete skull bone structure , stable and reproducible mandibular position , no obvious skeletal asymmetry and normal anterior bite or mild deep bite ( maximum deep bite is on the lingual cervical one third of upper incisors ) or mild open bite ( maximum of edge to edge bite ) .
a team of orthodontists checked the occlusion of each specimen to confirm stability and reproducibility before scanning .
silicone plaster was placed in the joint space between the mandibular fossa and the condylar head to improve stability .
the orientation protocol and reference system were set up in maxilim software as described by swennen et al . .
orienting the skulls in 3d space was carried out in a similar manner to that which radiologists use to position a patient s head in a cephalostat
. however , the operators of 3d images have far more anatomical structures as objective references than radiologists . the lateral and frontal cephalograms ( fig .
1 ) were combined with frontal and caudocranial views ( fig . 2 ) to reconfirm head positioning .
in the lateral film the bilateral structures should be perfectly superimposed , especially on the mandibular inferior border and the central axis of the skull should be parallel to the lateral film ( fig
the median reference plane should pass through the central axis of the skull in the caudocranial view ( fig . 2 ) .
the bilateral structures should be perfectly superimposed especially on the mandibular inferior border ( left ) and the central axis of the skull should be parallel to the lateral film ( right ) in the lateral film the bilateral structures should be perfectly superimposed especially on the mandibular inferior border ( left ) and the central axis of the skull should be parallel to the lateral film ( right ) fig .
2the median reference plane is shown passing the central axis of the skull in the frontal ( left ) and caudocranial ( right ) views the median reference plane is shown passing the central axis of the skull in the frontal ( left ) and caudocranial ( right ) views once the points of sella ( s ) and nasion ( n ) were defined the 3d cephalometric reference system was automatically generated by the computer .
although most of the 3d landmarks were easily visualized and identified in reconstructed 3d virtual space some landmarks , such as the condyle could not be directly visualized . under these conditions
the coronal and sagittal slice view was used to help locate the landmarks ( fig .
6 ) and this coronal and sagittal slice view was also used to check if the landmarks had been correctly located in the reconstructed 3d virtual space .
3the 3d landmarks in the frontal view : 1 n , 2 ans , 3 a , 4 b , 5 pg , 6 me , 7 max , 8 zyg and 9 frz the 3d landmarks in the frontal view : 1 n , 2 ans , 3 a , 4 b , 5 pg , 6 me , 7 max , 8 zyg and 9 frz fig .
4the 3d landmarks in the lateral view : 1 n , 2 ans , 3 a , 4 b , 5 pg , 6 go , 7 max , 8 zyg and 9 s the 3d landmarks in the lateral view : 1 n , 2 ans , 3 a , 4 b , 5 pg , 6 go , 7 max , 8 zyg and 9 s fig .
5the 3d landmarks in the caudocranial view : 1 zyg , 2 go , 3 ba , 4 pns , 5 me and 6 pg the 3d landmarks in the caudocranial view : 1 zyg , 2 go , 3 ba , 4 pns , 5 me and 6 pg fig .
6coronal ( left ) and sagittal ( right ) slice view of the condyle ( co ) landmark coronal ( left ) and sagittal ( right ) slice view of the condyle ( co ) landmark table 1description of the 3d cephalometric landmarks used in this studylandmarkdefinitions ( sella)midpoint of the pituitary fossa in the sagittal planen ( nasion)middle point of the frontonasal suture in the frontal planefrz ( frontozygomatic point)intersection of the frontozygomatic suture and the inner rim of the orbit in the frontal planemax ( maxillary basal point)points in the lateral outline of the maxilla at which the lateral surfaces of the maxilla turn into the inferior surfaces of the maxillary zygometic processes in the frontal planeans ( anterior nasal spine)most anterior point of the premaxillary bone in the sagittal planepns ( posterior nasal spine)most posterior point of the palatine bone in the sagittal planea ( point a)deepest point in the anterior outline of the maxilla between supradental and anterior nasal spine in the sagittal planeb ( point b)deepest point in the anterior outline of the mandible between infradental and pogonion in the sagittal planepg ( pogonion)most anterior point in the mandibular chin area in the sagittal planegn ( gnathion)middle point between pg and me at the surface of mandibular chin in the sagittal planeme ( menton)most inferior point in the mandibular chin area in the sagittal plango ( gonion)point in the inferoposterior outline of the mandible at which the surface turns from the inferior border into the posterior border in the sagittal planeco ( condyle)most posterosuperior point of mandibular condyle.zyg ( zygomatic)most lateral aspect of the zygomatic archba ( basion)anterior - inferior margin of the foramen magnum description of the 3d cephalometric landmarks used in this study table 2 and figs . 7 , 8
the dimensions of height were mostly measured along the vertical axis ( fig . 7 ) except for the mandibular ramus , which was measured directly from the co to go . in this way the 3d length of the mandibular ramus was obtained . to study the complete structure the true length was important rather than the projected length which was liable to be influenced by a poor head position .
the only angle measurement applied in this study was mp - sn and the ratio measurement s - go / n - me . as for the measurements of bilateral sides the means of the values measured on the bilateral sides were considered as final values .
7lateral view of height measurements : 1 n - me , 2 ans - me , 3 s - go , 4 co - go lateral view of height measurements : 1 n - me , 2 ans - me , 3 s - go , 4 co - go fig .
8lateral ( left ) and caudiocranial ( right ) views of depth measurements : 1 s - n , 2 s - b , 3 s - a , 4 s - ba , 5 ba - n , 6 ans - pns , 7 go - gn lateral ( left ) and caudiocranial ( right ) views of depth measurements : 1 s - n , 2 s - b , 3 s - a , 4 s - ba , 5 ba - n , 6 ans - pns , 7 go - gn fig .
9frontal view of width measurements : 1 frz - frz , 2 co - co , 3 zyg - zyg , 4 max - max , 5 go - go frontal view of width measurements : 1 frz - frz , 2 co - co , 3 zyg - zyg , 4 max - max , 5 go - go table 2definition of the measurements used in this studymeasurementdefinition
width
frz - frzdistance between the right and the left frz along the transverse - axiszyg - zygdistance between the right and the left zyg along the transverse - axismax - maxdistance between the right and the left max along the transverse - axisco - codistance between the right and the left co along the transverse axisgo - godistance between the right and the left go along the transverse axis
height
n - me ( total face height)distance between n and me along the vertical axisn - ans ( upper face height)distance between n and ans along the vertical axisans - me ( lower face height)distance between ans and me along the vertical axisco - go ( ramus length)distance between co and gos - go ( posterior height)distance between s and go along the vertical axiss - go / n - meratio of the linear measurement s - go to n - memp / snangle between the projection of the lines of mp and sn on the median plane where mp plane is defined as connecting go and me
depth
s - ndistance between s and ns - badistance between s and ba along the anteroposterior axisba - ndistance between ba and n along the anteroposterior axisans - pnsdistance between the projection of ans and pnsgo - gndistance between point go and point gns - adistance between s and a along the anteroposterior axiss - bdistance between s and b along the anteroposterior - axis definition of the measurements used in this study depth was mostly measured along the anteroposterior - axis ( fig .
8) except the distances between s and n , between ans and pns and between go and gn .
the reason as mentioned before was that the study focused on the actual length of cranial base , the maxilla and the mandibular corpus rather than the projected length .
because direct measurements between identical anatomic structures of bilateral sides indicate not only width but also the vertical and anteroposterior difference between them , values measured along the transverse axis were defined as width ( fig .
pearson correlation coefficients among facial height measurements and mandibular plane angle and the correlation coefficients of height - width and height - depth were calculated , respectively and were considered significant when p < 0.01 and probably significant when p ranged between 0.01 and < 0.05 . the absolute value of r was used to arbitrarily classify the correlation as low , moderate or high when it was < 0.40 , 0.400.80 or > 0.80 , respectively and when r was between zero and 1 the correlation was positive and when between 1 and zero it was negative . before the pearson correlation analysis , the normal distribution of all measurements had been tested and all the data were normally distributed .
the same investigator located the same landmarks and measured the same items on 25 randomly selected cbct images as described above at a 4-week interval to assess the intraobserver reproducibility .
random errors were estimated by correlation analysis and the reliability coefficient between the repeat measurements ranged from 0.893 to 0.991 .
systematic errors were assessed using a paired t - test at the 10 % level of significance as houston suggested and no systematic errors were detected .
the sample consisted of the cbct data from 43 dry skulls which had been previously acquired in the natural history museum of vienna by scanning the dry skulls of the weisbach collection which includes the dry skulls of soldiers of the austrian imperial army who died around 1870 .
archival records show that the skulls mainly belonged to adult males who died between the ages of 19 and 50 years .
the following inclusion criteria were used in this study : no cranial deformities , complete skull bone structure , stable and reproducible mandibular position , no obvious skeletal asymmetry and normal anterior bite or mild deep bite ( maximum deep bite is on the lingual cervical one third of upper incisors ) or mild open bite ( maximum of edge to edge bite ) .
a team of orthodontists checked the occlusion of each specimen to confirm stability and reproducibility before scanning .
silicone plaster was placed in the joint space between the mandibular fossa and the condylar head to improve stability .
a plastic holder was custom - designed to support skulls during ct scanning . for the details on image acquisition
the orientation protocol and reference system were set up in maxilim software as described by swennen et al . .
orienting the skulls in 3d space was carried out in a similar manner to that which radiologists use to position a patient s head in a cephalostat
. however , the operators of 3d images have far more anatomical structures as objective references than radiologists . the lateral and frontal cephalograms ( fig .
1 ) were combined with frontal and caudocranial views ( fig . 2 ) to reconfirm head positioning .
in the lateral film the bilateral structures should be perfectly superimposed , especially on the mandibular inferior border and the central axis of the skull should be parallel to the lateral film ( fig . 1 ) .
the median reference plane should pass through the central axis of the skull in the caudocranial view ( fig . 2 ) .
the bilateral structures should be perfectly superimposed especially on the mandibular inferior border ( left ) and the central axis of the skull should be parallel to the lateral film ( right ) in the lateral film the bilateral structures should be perfectly superimposed especially on the mandibular inferior border ( left ) and the central axis of the skull should be parallel to the lateral film ( right ) fig .
2the median reference plane is shown passing the central axis of the skull in the frontal ( left ) and caudocranial ( right ) views the median reference plane is shown passing the central axis of the skull in the frontal ( left ) and caudocranial ( right ) views once the points of sella ( s ) and nasion ( n ) were defined the 3d cephalometric reference system was automatically generated by the computer .
although most of the 3d landmarks were easily visualized and identified in reconstructed 3d virtual space some landmarks , such as the condyle could not be directly visualized . under these conditions
the coronal and sagittal slice view was used to help locate the landmarks ( fig .
6 ) and this coronal and sagittal slice view was also used to check if the landmarks had been correctly located in the reconstructed 3d virtual space .
3the 3d landmarks in the frontal view : 1 n , 2 ans , 3 a , 4 b , 5 pg , 6 me , 7 max , 8 zyg and 9 frz the 3d landmarks in the frontal view : 1 n , 2 ans , 3 a , 4 b , 5 pg , 6 me , 7 max , 8 zyg and 9 frz fig .
4the 3d landmarks in the lateral view : 1 n , 2 ans , 3 a , 4 b , 5 pg , 6 go , 7 max , 8 zyg and 9 s the 3d landmarks in the lateral view : 1 n , 2 ans , 3 a , 4 b , 5 pg , 6 go , 7 max , 8 zyg and 9 s fig .
5the 3d landmarks in the caudocranial view : 1 zyg , 2 go , 3 ba , 4 pns , 5 me and 6 pg the 3d landmarks in the caudocranial view : 1 zyg , 2 go , 3 ba , 4 pns , 5 me and 6 pg fig . 6coronal ( left ) and sagittal ( right ) slice view of the condyle ( co ) landmark coronal ( left ) and sagittal ( right ) slice view of the condyle ( co ) landmark table 1description of the 3d cephalometric landmarks used in this studylandmarkdefinitions ( sella)midpoint of the pituitary fossa in the sagittal planen ( nasion)middle point of the frontonasal suture in the frontal planefrz ( frontozygomatic point)intersection of the frontozygomatic suture and the inner rim of the orbit in the frontal planemax ( maxillary basal point)points in the lateral outline of the maxilla at which the lateral surfaces of the maxilla turn into the inferior surfaces of the maxillary zygometic processes in the frontal planeans ( anterior nasal spine)most anterior point of the premaxillary bone in the sagittal planepns ( posterior nasal spine)most posterior point of the palatine bone in the sagittal planea ( point a)deepest point in the anterior outline of the maxilla between supradental and anterior nasal spine in the sagittal planeb ( point b)deepest point in the anterior outline of the mandible between infradental and pogonion in the sagittal planepg ( pogonion)most anterior point in the mandibular chin area in the sagittal planegn ( gnathion)middle point between pg and me at the surface of mandibular chin in the sagittal planeme ( menton)most inferior point in the mandibular chin area in the sagittal plango ( gonion)point in the inferoposterior outline of the mandible at which the surface turns from the inferior border into the posterior border in the sagittal planeco ( condyle)most posterosuperior point of mandibular condyle.zyg ( zygomatic)most lateral aspect of the zygomatic archba ( basion)anterior - inferior margin of the foramen magnum description of the 3d cephalometric landmarks used in this study table 2 and figs . 7 , 8 , 9 show the measurements designed in this 3d study .
the dimensions of height were mostly measured along the vertical axis ( fig . 7 ) except for the mandibular ramus , which was measured directly from the co to go . in this way the 3d length of the mandibular ramus was obtained . to study the complete structure the true length was important rather than the projected length which was liable to be influenced by a poor head position .
the only angle measurement applied in this study was mp - sn and the ratio measurement s - go / n - me . as for the measurements of bilateral sides the means of the values measured on the bilateral sides were considered as final values .
7lateral view of height measurements : 1 n - me , 2 ans - me , 3 s - go , 4 co - go lateral view of height measurements : 1 n - me , 2 ans - me , 3 s - go , 4 co - go fig . 8lateral ( left ) and caudiocranial ( right ) views of depth measurements : 1 s - n , 2 s - b , 3 s - a , 4 s - ba , 5 ba - n , 6 ans - pns , 7 go - gn lateral ( left ) and caudiocranial ( right ) views of depth measurements : 1 s - n , 2 s - b , 3 s - a , 4 s - ba , 5 ba - n , 6 ans - pns , 7 go - gn fig .
9frontal view of width measurements : 1 frz - frz , 2 co - co , 3 zyg - zyg , 4 max - max , 5 go - go frontal view of width measurements : 1 frz - frz , 2 co - co , 3 zyg - zyg , 4 max - max , 5 go - go table 2definition of the measurements used in this studymeasurementdefinition
width
frz - frzdistance between the right and the left frz along the transverse - axiszyg - zygdistance between the right and the left zyg along the transverse - axismax - maxdistance between the right and the left max along the transverse - axisco - codistance between the right and the left co along the transverse axisgo - godistance between the right and the left go along the transverse axis
height
n - me ( total face height)distance between n and me along the vertical axisn - ans ( upper face height)distance between n and ans along the vertical axisans - me ( lower face height)distance between ans and me along the vertical axisco - go ( ramus length)distance between co and gos - go ( posterior height)distance between s and go along the vertical axiss - go / n - meratio of the linear measurement s - go to n - memp / snangle between the projection of the lines of mp and sn on the median plane where mp plane is defined as connecting go and me
depth
s - ndistance between s and ns - badistance between s and ba along the anteroposterior axisba - ndistance between ba and n along the anteroposterior axisans - pnsdistance between the projection of ans and pnsgo - gndistance between point go and point gns - adistance between s and a along the anteroposterior axiss - bdistance between s and b along the anteroposterior - axis definition of the measurements used in this study depth was mostly measured along the anteroposterior - axis ( fig .
8) except the distances between s and n , between ans and pns and between go and gn .
the reason as mentioned before was that the study focused on the actual length of cranial base , the maxilla and the mandibular corpus rather than the projected length .
because direct measurements between identical anatomic structures of bilateral sides indicate not only width but also the vertical and anteroposterior difference between them , values measured along the transverse axis were defined as width ( fig .
pearson correlation coefficients among facial height measurements and mandibular plane angle and the correlation coefficients of height - width and height - depth were calculated , respectively and were considered significant when p < 0.01 and probably significant when p ranged between 0.01 and < 0.05 . the absolute value of r was used to arbitrarily classify the correlation as low , moderate or high when it was < 0.40 , 0.400.80 or > 0.80 , respectively and when r was between zero and 1 the correlation was positive and when between 1 and zero it was negative . before the pearson correlation analysis , the normal distribution of all measurements had been tested and all the data were normally distributed .
the same investigator located the same landmarks and measured the same items on 25 randomly selected cbct images as described above at a 4-week interval to assess the intraobserver reproducibility .
random errors were estimated by correlation analysis and the reliability coefficient between the repeat measurements ranged from 0.893 to 0.991 .
systematic errors were assessed using a paired t - test at the 10 % level of significance as houston suggested and no systematic errors were detected .
table 3descriptive statistics of each measurement used in the studyvariable
n
minimum ( mm)maximum ( mm)mean ( mm)standard deviation ( mm)frz - frz4384.6099.9092.993.52max - max4354.3070.0061.713.74zyg - zyg43116.10138.40124.755.32co - co4382.5099.3092.814.67go - go4381.70107.8094.256.26mp - sn4319.3539.0029.865.18s - go / n - me4359.4080.2069.134.44n - me4398.10122.50111.875.48n - ans4343.1055.3049.443.03ans - me4353.5079.4062.445.65s - go4362.2587.1077.346.06co - go4348.4068.1058.024.62s - n4355.172.765.823.41ans - pns4339.7055.5049.593.86s - a4351.8075.0065.884.77s - b4341.4077.0060.277.28go - gn4377.3598.5587.024.79s - ba4317.9032.9025.303.59ba - n4378.60101.7090.715.03for explanation of terms see tables 1 and 2
descriptive statistics of each measurement used in the study for explanation of terms see tables 1 and 2
on the correlations among height measurements , mp - sn , s - go / n - me ratio ( table 4 ) , co - go and s - go moderately correlated with both mp - sn and the s - go / n - me ratio .
the afh , including anterior upper face height ( aufh measured between n and ans ) , anterior lower face height ( alfh measured between ans and me ) and anterior total face height ( atfh measured between n and me ) did not significantly correlate with either mp - sn or s - go / n - me , whereas atfh and alfh moderately and positively correlated with co - go and s - go .
table 4correlations between height measurements , mp - sn and s - go / n - me ratiovariablemp - sns - go / n - meco - gos - gon - ansn - mes - go / n - me0.902
1co - go0.464
0.635
1s - go0.572
0.787
0.846
1n - ans0.0350.0830.1550.2041n - me0.2620.0450.535
0.580
0.2201ans - me0.2390.0920.433
0.450
0.321
0.853
correlation is significant at the 0.01 level ( 2-tailed )
correlation is significant at the 0.05 level ( 2-tailed)for explanation of terms see tables 1 and 2
correlations between height measurements , mp - sn and s - go / n - me ratio
correlation is significant at the 0.01 level ( 2-tailed )
correlation is significant at the 0.05 level ( 2-tailed ) for explanation of terms see tables 1 and 2
on the significant correlations between height and width ( table 5 ) the bizygomatic ( zyg - zyg ) distance significantly correlated with co - go , s - go , s - go / n - me and mp - sn and co - go also showed low correlation with both the bicondylar ( co - co ) and the bigonial ( go - go ) width .
table 5statistically significant correlations of height and widthvariablezyg - zyggo - goco - coco - go0.390
0.340
0.349
s - go0.371
0.2040.290mp - sn0.401
0.0170.181s - go / n - me0.414
0.0770.247
correlation is significant at the 0.01 level ( 2-tailed)correlation is significant at the 0.05 level ( 2-tailed)for explanation of terms see tables 1 and 2
statistically significant correlations of height and width
correlation is significant at the 0.01 level ( 2-tailed)correlation is significant at the 0.05 level ( 2-tailed ) for explanation of terms see tables 1 and 2
as for the statistically significant correlations between height and depth ( table 6 ) , afh , atfh and alfh showed moderate correlation with s - n and relatively lower correlation with ans - pns and s - a . on the other hand , co - go and s - go correlated moderately with s - a and s - b and slightly with ans - pns and go - gn .
table 6statistically significant correlations of facial height and depthvariables - ns - aans - pnss - bgo - gnn - me0.562
0.498
0.395
0.2820.241ans - me0.509
0.382
0.320
0.2740.258s - go0.2500.485
0.304
0.526
0.288co - go0.2770.435
0.400
0.361
0.357
correlation is significant at the 0.01 level ( 2-tailed )
correlation is significant at the 0.05 level ( 2-tailed)for explanation of terms see tables 1 and 2
statistically significant correlations of facial height and depth
correlation is significant at the 0.01 level ( 2-tailed )
correlation is significant at the 0.05 level ( 2-tailed)for explanation of terms see tables 1 and 2
although it was reasonable to find that mp - sn and pfh / atfh showed moderate correlation with the pfh and the ramus height , it was quite implausible to discover that neither mp - sn nor pfh / atfh correlated with any afh measurements ( table 4 and fig . 10 ) . even as the denominator of pfh / atfh , atfh did not correlate with this ratio .
this might suggest that in normal overbite case the pfh or the ramus height rather than afh appears to play a key role in vertical facial type .
10correlations between mandibular plane angle with posterior height ( upper left
) , ramus height ( upper right ) , anterior total face height ( lower left ) and anterior lower face height ( lower right ; for explanation of terms see tables 1 and 2 ) correlations between mandibular plane angle with posterior height ( upper left
) , ramus height ( upper right ) , anterior total face height ( lower left ) and anterior lower face height ( lower right ; for explanation of terms see tables 1 and 2 ) at the same time , pfh and ramus height moderately and positively correlated with atfh and alfh ( table 4 ) which means that a face with a long pfh is normally accompanied by a relatively long afh and vice versa .
therefore , in a normal overbite case , mandibular forward rotation can not be simply regarded as the growth result of relatively long pfh together with relatively short afh . in other words ,
the reason for mandibular forward rotation is not because of increase of pfh together with a decrease of afh but the different increased dimension of them .
these study results showed that it is the underdevelopment or overdevelopment of pfh instead of afh that plays a key role in mandibular rotation .
this agrees with bjrk who stated that under ideal circumstances the fulcrum point for anterior or forward mandibular growth rotation is located at the incisors .
therefore , as the result of forward rotation both the afh and pfh increase . on the other hand , extreme short or long face syndrome is definitely always accompanied by low or high mandibular plane angle . however , in the extreme case , muscle or organ dysfunction , such as nasal obstruction is suggested to be always involved .
this kind of dysfunction probably interferes with the functional capacity of adaptation that normal faces are supposed to have .
van spronsen et al . argued that musculoskeletal interactions might differ between populations with normal faces and a select group of individuals with long faces .
as for the normal overbite person observed in this study , which can perfectly compensate some discrepancy within a certain extent , the mandibular plane angle was by no means associated with the anterior face height . as for the reason why in relatively normal cases , the pfh instead of afh plays a key role in mandibular rotation
several authors have stated that the morphology and position of the mandible should be adaptable to functional demand in the occlusal configuration [ 21 , 31 ] .
the posterior part of the dentition has furthermore been proposed as a main factor affecting the functional positioning of the mandible [ 14 , 30 , 8 ] the longitudinal growth studies conducted by tanaka and sato revealed that continuous horizontalization of the posterior occlusal plane is accompanied by a simultaneous reduction in the mandibular plane angle during growth .
they suggested that the posterior occlusal plane is the key point responsible for changes in mandibular position .
if this assumption is valid , the possibility can be raised that with the horizontalization of the posterior occlusal plane , the vertical growth of mandible ramus might be obtained and as a result the mandibular plane will flatten ( fig .
11diagram of the lateral view of the skull showing that horizontalization of the posterior occlusal plane causes more vertical growth of mandible ramus and the mandibular plane will become flat .
alfh anterior lower face height , op occlusal plane and mp mandibular plane diagram of the lateral view of the skull showing that horizontalization of the posterior occlusal plane causes more vertical growth of mandible ramus and the mandibular plane will become flat .
alfh anterior lower face height , op occlusal plane and mp mandibular plane with respect to the correlation between face height and depth , atfh and alfh moderately correlated with anterior cranial base length ( s - n ) , whereas pfh and anterior cranial base length did not correlate .
as s - n is generally considered stable and reliable , environmental or functional factors seem less likely to change the s - n length .
this might suggest that in normal cases , afh is more likely to undergo relatively intrinsic growth than pfh or it is not easily influenced by functional factors such as changes in the posterior occlusal plane as noted above . with respect to the posterior height ,
it weakly associated with the actual mandibular length and maxilla length and moderately and positively correlated with the anteroposterior position of the mandible and maxilla .
that sounds reasonable with afh being regarded as vertical height in the extreme case of long or short face type . in relative normal overbite case ,
however , as this study showed the vertical growth of pfh is consistent with anteroposterior growth . in order to correct the anteroposterior discrepancy ,
orthodontists have tried to stimulate the capacity of adaptation to changes in mandibular position and non - human primate studies have demonstrated that the temporomandibular joint in the condylar region definitely has such functional capacity [ 22 , 12 ] . according to mcnamara and bryan and mcnamara the dentofacial complex is adaptable to the functional demands in the occlusal configuration even in young adult monkeys .
clinical studies , however , also by mcnamara using a functional regulator on adult humans , manifested that only minimal skeletal and dental adaptation occurred and that adaptation were considered insufficient to completely resolve patient malocclusions .
it seems that for adults the protrusive function only is not enough to maintain the mandible in the forward position .
sato et al . , sasaguri et al . and tanaka et al .
tried to maintain the mandible in the forward position by changing the occlusal configuration not only anterioposteriorly but also vertically . as a result ,
obvious remodelling of the condyle in adults has been found [ 26 , 29 , 36 ] .
they suggested that the stable condyle adaptation might be available when the occlusal plane was reconstructed with either an orthodontic or prosthetic approach by increasing posterior teeth support , horizontalizing posterior occlusal plane and as a result the mandible being forward rotated . together with the present study
it can be deduced that to obtain enough mandible anteroposterior growth or forward adaptation a correct increase of posterior height might be an important factor . as for the correlation between height and width , the ramus height together with the mandibular plane angle and the pfh / atfh moderately correlated with the bizygomatic width and the width of co - co and go - go also correlated with ramus height to some extent , which implies that the bicondylar and bigonial width of the mandible is related to the height of the mandibular ramus .
thus , a face with a low angle , normally accompanied by a long ramus and a wide frontal region ( wide bizygomatic and bigonial ) can easily produce an illusion of a short face , although the anterior lower face height could be normal .
this also explains why many faces with a low angle are taken for granted to be assumed as a short face , whereas a wide face and a square profile are responsible for making faces appear short . in this study , depending on different purposes , direct or projected measurement was selected as the research method .
the direct measurement method was used when the complete structure was evaluated , for instance , in measuring ramus length , mandibular corpus length and anterior cranial base length .
the reason was that in this situation the study was more concerned with the real length of the structures than the projected ones and the direct measurement results could not be influenced by a poor position of the skull . in previous 2d cephalometric studies , however , as there is no way to measure the true length of any structure , observers had to make use of the projected length .
the projected measurement was used here in the width measurement because only the width of identical anatomic structures on bilateral sides was made and direct measurements indicate not only width but also the vertical and anteroposterior difference between them .
the larger vertical and anteroposterior difference of bilateral sides was , the more enlarged value was obtained compared with the actual result . in this study pearson correlation
coefficients were used to find out the interrelationship among 3d structures . with these findings human craniofacial architecture and its multiple interactions among structures can be better understood but correlation studies can not answer the cause and effect relationship among structures and also that between the skeletal morphology and jaw muscle function remain unclear .
within the limitations of this 3d cbct study on skulls of relatively normal adult caucasian males it was concluded that low or high mandibular plane angle might not necessarily be accompanied by short or long afh , respectively as has commonly been believed .
the pfh rather than afh is assumed to play a key role in the vertical facial type , whereas afh seems to undergo relatively intrinsic growth .
the authors declare that there are no actual or potential conflicts of interest in relation to this article .
this article is distributed under the terms of the creative commons attribution noncommercial license which permits any noncommercial use , distribution , and reproduction in any medium , provided the original author(s ) and the source are credited .
the authors declare that there are no actual or potential conflicts of interest in relation to this article .
this article is distributed under the terms of the creative commons attribution noncommercial license which permits any noncommercial use , distribution , and reproduction in any medium , provided the original author(s ) and the source are credited .
Output:
| introductionthe aim of the present study was to evaluate how vertical facial height correlates with mandibular plane angle , facial width and depth from a three dimensional ( 3d ) viewing angle.methodsin this study 3d cephalometric landmarks were identified and measurements from 43 randomly selected cone beam computed tomography ( cbct ) images of dry skulls from the weisbach collection of vienna natural history museum were analyzed .
pearson correlation coefficients of facial height measurements and mandibular plane angle and the correlation coefficients of height - width and height - depth were calculated , respectively.resultsthe mandibular plane angle ( mp - sn ) significantly correlated with ramus height ( co - go ) and posterior facial height ( pfh ) but not with anterior lower face height ( alfh ) or anterior total face height ( atfh ) .
the alfh and atfh showed significant correlation with anterior cranial base length ( s - n ) , whereas pfh showed significant correlation with the mandible ( s - b ) and maxilla ( s - a ) anteroposterior position.conclusionshigh or low mandibular plane angle might not necessarily be accompanied by long or short anterior face height , respectively .
the pfh rather than afh is assumed to play a key role in the vertical facial type whereas afh seems to undergo relatively intrinsic growth . |
PubmedSumm118759 | ***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: open surgical repair remains a gold standard therapeutic option in the management of descending thoracic aorta ( dta ) aneurysm . because of the progress in cardiopulmonary bypass ( cpb ) strategies , spinal cord protective adjuncts , as well as improvements in postoperative care ,
outcomes of open repair of dta have improved [ 13 ] . despite these improvements ,
morbidity and mortality rates in dta replacement still remain high [ 24 ] , with the recent data showing operative mortality rate of 4.7% , lower extremity paralysis rate of 3.4% , and stroke rate of 2.7% even in the high - volume aortic centers .
, concerns regarding the challenging risks of open surgical repair of dta have led to the global atmosphere favoring thoracic endovascular aortic repair ( tevar ) more frequently even without hard evidence in support of the long - term benefits of tevar .
reviewing the literature published in korea , only a few studies have analyzed clinical outcomes of open surgical repair of dta , of which the largest - scale study is one that evaluated 22 patients decades ago .
we therefore sought to evaluate the outcomes following open surgical repair of dta in a reasonably sized cohort in the current era and to determine independent predictors of long - term outcomes .
out of 212 patients who underwent dta repair between june 1999 and august 2011 at asan medical center , we identified 103 patients ( mean age , 53.813.1 years ; 23 women ) who underwent aortic surgery only for thoracic aortic segments .
one hundred and nine patients who underwent aortic surgery combined with thoracoabdominal aorta repair and arch replacement were excluded in this study .
the operative procedure was conducted as follows : patients were intubated with a double lumen endotracheal tube .
cerebrospinal fluid ( csf ) drainage was in 56 patients ( 54% ) who were supposed to receive lower thoracic aorta replacement . left posterolateral thoracotomy was performed for all patients , and the level of entrance ( 46th intercostal spaces ) was determined on the basis of the aortic segment replaced .
the left femoral artery was the preferred site for arterial cannulation in the absence of atherosclerotic changes in the distal arteries .
in general , arterial and venous cannulation was established with a wire - directed approach .
deep hypothermic circulatory arrest ( dhca ) was used in 44 patients ( 42.7% ) , and partial cbp was used in 58 patients ( 56.3% ) . the decision between dhca versus partial cpb strategies depended on anatomic factors including involvement of the distal arch or feasibility of aortic cross - clamping , but
the patients who underwent dhca ( n=44 , 45% ) were cooled to the core body temperature of 18c , and when circulatory arrest was initiated , the aorta was opened .
proximal aortic anastomosis was made with a branched vascular graft in an open fashion , and then , an additional arterial cannula was inserted through the side branch of the aortic graft so that both the upper and the lower body could be perfused . for partial cpb strategies ,
proximal dta clamping or distal arch clamping ( between left common carotid and left subcalvian artery [ lsca ] ) with separate lsca clamping was performed under mild hypothermia ( > 30c ) .
distal anastomosis was performed in an open fashion if distal clamping was not feasible in both dhca and partial cpb techniques .
after cpb weaning , protamine was administered to return the activated clotting times to baseline .
stroke was defined as any new clinically and radiographically evident brain injury including focal and global deficits .
paraplegia was defined as a deficit of the lower extremities including weakness or complete loss of motor function . for study purposes ,
renal failure was defined as the new requirement for hemodialysis , and low cardiac output syndrome ( lcos ) was defined as heart failure requiring mechanical ventricular support such as intra - aortic balloon pulsation or veno - arterial extracorporeal membrane oxygenation .
categorical variables were presented as frequencies and percentages , and continuous variables were expressed as meanstandard deviation or medians with inter - quartile ranges . for multivariable analyses , cox proportional hazards models were used to determine the risk factors of death .
variables listed in table 1 were evaluated in the models , and those with a p - value of 0.20 or less in the univariable analyses were candidates for the multivariable cox models .
multivariable analyses involved a backward elimination technique , and only variables with a p - value of less than 0.10 were used in the final model .
all statistical analyses were performed with pasw spss ver . 18.0 ( spss inc . , chicago , il , usa ) .
out of 212 patients who underwent dta repair between june 1999 and august 2011 at asan medical center , we identified 103 patients ( mean age , 53.813.1 years ; 23 women ) who underwent aortic surgery only for thoracic aortic segments .
one hundred and nine patients who underwent aortic surgery combined with thoracoabdominal aorta repair and arch replacement were excluded in this study .
the operative procedure was conducted as follows : patients were intubated with a double lumen endotracheal tube .
cerebrospinal fluid ( csf ) drainage was in 56 patients ( 54% ) who were supposed to receive lower thoracic aorta replacement . left posterolateral thoracotomy was performed for all patients , and the level of entrance ( 46th intercostal spaces ) was determined on the basis of the aortic segment replaced .
the left femoral artery was the preferred site for arterial cannulation in the absence of atherosclerotic changes in the distal arteries .
in general , arterial and venous cannulation was established with a wire - directed approach .
deep hypothermic circulatory arrest ( dhca ) was used in 44 patients ( 42.7% ) , and partial cbp was used in 58 patients ( 56.3% ) . the decision between dhca versus partial cpb strategies depended on anatomic factors including involvement of the distal arch or feasibility of aortic cross - clamping , but
the patients who underwent dhca ( n=44 , 45% ) were cooled to the core body temperature of 18c , and when circulatory arrest was initiated , the aorta was opened .
proximal aortic anastomosis was made with a branched vascular graft in an open fashion , and then , an additional arterial cannula was inserted through the side branch of the aortic graft so that both the upper and the lower body could be perfused . for partial cpb strategies ,
proximal dta clamping or distal arch clamping ( between left common carotid and left subcalvian artery [ lsca ] ) with separate lsca clamping was performed under mild hypothermia ( > 30c ) .
distal anastomosis was performed in an open fashion if distal clamping was not feasible in both dhca and partial cpb techniques .
after cpb weaning , protamine was administered to return the activated clotting times to baseline .
stroke was defined as any new clinically and radiographically evident brain injury including focal and global deficits .
paraplegia was defined as a deficit of the lower extremities including weakness or complete loss of motor function . for study purposes ,
renal failure was defined as the new requirement for hemodialysis , and low cardiac output syndrome ( lcos ) was defined as heart failure requiring mechanical ventricular support such as intra - aortic balloon pulsation or veno - arterial extracorporeal membrane oxygenation .
categorical variables were presented as frequencies and percentages , and continuous variables were expressed as meanstandard deviation or medians with inter - quartile ranges . for multivariable analyses , cox proportional hazards models were used to determine the risk factors of death .
variables listed in table 1 were evaluated in the models , and those with a p - value of 0.20 or less in the univariable analyses were candidates for the multivariable cox models .
multivariable analyses involved a backward elimination technique , and only variables with a p - value of less than 0.10 were used in the final model .
all statistical analyses were performed with pasw spss ver . 18.0 ( spss inc . , chicago , il , usa ) .
eleven patients ( 10.7% ) underwent emergency or urgent surgeries as indicated in table 1 .
cpb time was longer in the dhca group ( 196.459.7 minutes versus 116.984.0 minutes , p<0.001 ) , and mean circulatory arrest time was 23.313.5 minutes in the dhca group .
the causes of early deaths were lcos in all patients , among which four patients showed multi - organ failure
. regarding the early mortality cases , one patient had low left ventricle ( lv ) ejection fraction ( 35% ) preoperatively , in whom partial cpb strategy was applied .
early major complications occurred in 21 patients ( 20.3% ) including 7 patients ( 6.8% ) of re - exploration for postoperative bleeding .
ten patients ( 9.7% ) required new dialysis for acute renal failure and 7 patients ( 6.8% ) developed stroke , but no cases of paraplegia were reported . between the dhca group and the partial cpb group , the dhca group had a higher rate of lcos ( 13.3% versus 1.7% , p=0.041 ) and
the duration of mechanical ventilation was longer than in the partial cpb group . during the median follow - up duration of 56.3 months ( inter - quartile range , 23.1 to 85.1 months )
, there were 17 ( 16.5% ) late mortalities including 11 cardiovascular - related deaths .
non - cardiovascular causes of death were malignancy in one , respiratory failure in four , and alcoholic liver disease in one patient .
the overall survival rates at 5 and 10 years were 80.9%4.3% and 71.7%5.9% , respectively ( fig .
1 ) . the 5- and 10-year reoperation - free survival rates were 77.3%4.8% and 70.2%5.8% , respectively ( fig .
there was one aortic reoperation case during follow - up , in whom asymptomatic pseudoaneurysm at the anastomoses site was seen at regular follow - up computed tomography performed 3 months after surgery .
the patient variables associated with mortality in the univariate analysis were age ( p<0.001 ) , lv ejection fraction ( p=0.001 ) , and glomerular filtration rate ( p=0.002 ) .
multivariable analyses revealed that age ( hazard ratio [ hr ] , 1.10 ; 95% confidence interval [ ci ] , 1.05 to 1.15 ; p<0.001 ) and lv function ( hr , 0.88 ; 95% ci , 0.82 to 0.96 ; p<0.003 ) were significantly associated with mortality ( table 3 ) . ruptured aorta and urgent / emergency cases , however ,
furthermore , different cpb strategies ( p=0.49 ) and distal arch involvement ( p=0.92 ) did not significantly affect mortality .
open surgical repair remains a gold standard approach in the management of dta lesions requiring invasive intervention .
progress in pre - operative management and cpb strategies as well as adjunctive maneuvers to protect the kidneys , visceral organs , and central nervous system has significantly improved surgical outcomes . however , open surgical repair of dta is still regarded as a surgical challenge having a reported early mortality rate of 4.8% to 22.4% .
in addition , in the era of endovascular alternatives , patients who undergo open repair of dta generally have highly complex aortic pathology where tevar approaches are regarded inappropriate , and these circumstances make it more challenging for practicing surgeons to undertake open surgery for dta , particularly for surgeons in low - volume aortic centers . in the past decades , a number of researches have been conducted to improve the preservation of end - organ functions from ischemic damages . several perfusion techniques were developed such as dhca and partial cpb including femoral - femoral bypass and left heart bypass .
adjunctive strategies such as intercostal reimplantation , csf drainage , motor / somatosensory - evoked potential monitoring , and rapid renal cooling have also been developed . despite these improvements in surgical techniques and adjuncts for end - organ protection ,
recent studies reviewed that dhca for open repair of dta has several advantages over non - dhca [ 9,11,1315 ] .
first , a bloodless field without clamping the aorta can be obtained . in particular , since clamping of the aorta is not safe if the aortic disease involves the distal aortic arch , dhca may offer a safe environment for surgery in this situation .
patel et al . demonstrated that half of the patients suffered from postoperative stroke when cross - clamping was conducted for the atheromatous aortic arch , but the stroke rate decreased to 11% when dhca was used without aortic clamping .
secondly , hypothermia has a protective effect on the spinal cord and visceral organs by decreasing the oxygen demand . in support of this hypothesis ,
rokkas et al . reported that the spinal cord is protected by dhca not only by decreased metabolism but also by the inhibition of the release of excitatory amino acids in the extracellular neuronal space . in dhca strategies , however , prolonged cpb time may require more transfusion , and hypothermia induces impairment of coagulation cascade .
partial cpb strategies have certain advantages such as requirement for shorter cpb time than dhca , which consequently reduce the risks of coagulopathy and lethal intrapulmonary hemorrhage that may hamper postoperative recovery .
moreover , several recent studies reported excellent spinal cord protection using a mild - hypothermic distal perfusion technique in combination with csf drainage .
acher suggested that the quality of spinal cord protection relies mainly on perfusion , metabolism , and oxygen delivery to the spinal cord during mild hypothermia rather than the cpb strategies themselves .
spinal cord perfusion can be further augmented by csf drainage and maintaining the mean arterial pressure above 80 mmhg .
along with the optimization of the hemoglobin level , oxygen saturation and cardiac index are regarded important to prevent postoperative delayed paraplegia . in support of these previous reports
, the present study also showed that the cpb strategy was not significantly related to early mortality , multi - organ failure , neurologic injury , and arf .
although the rate of immediate postoperative lcos requiring mechanical support was higher in the dhca group ( table 2 ) , the cpb strategy did not affect long - term survival even in a univariate analysis ( table 3 ) .
the independent predictors were age ( hr , 1.10 ; 95% ci , 1.05 to 1.15 ; p<0.001 ) and lv ejection fraction ( hr , 0.88 ; 95% ci , 0.82 to 0.96 ; p < 0.003 ) , which are not factors adjustable by surgery . because of the retrospective nature of this study
however , considering the higher rates of lcos ( p=0.041 ) in the dhca group , we recently changed our strategy to assertively insert an lv vent ( via lv apex ) when conducting dhca . despite the improvements in the operative outcomes of open surgical repair of dta
early mortality rates following tevar are reported to be up to 7.4% and 4-year mortality after tevar for ruptured thoracic aneurysm has been estimated to be 25.4% . for elective cases ,
tevar was associated with lower risks of early death and complications compared with open repair of dta
. however , there are only a few studies that have compared long - term outcomes between tevar and open repair in dta . of note , makaroun et al .
reported that tevar showed a comparable 5-year survival rate ( 68% versus 67% , p - value=0.433 ) with that of open surgery .
nevertheless , the risk of vascular complications following tevar is reported to be substantial , and the 5-year re - intervention rate was reported to be 3.6% to 17% . in this regard , overall clinical outcomes including intervention - related complications should be compared between tevar and open surgery in further large - scale studies in order to determine optimal candidates for each treatment option .
this study is limited by a retrospective analysis that includes an inherent bias . non - randomized design may have affected the results because of unmeasured confounders , procedure bias , or detection bias , even with the use of rigorous statistical adjustment .
further , this study represents the experience of a single large tertiary referral center and might not be generalized to other centers .
the outcomes of open surgical repair of dta were feasible in terms of excellent perioperative mortality / morbidity as well as favorable long - term outcomes .
age and lv function were independent predictors of long - term mortality , whereas the surgical strategies did not significantly affect the clinical outcomes .
this study is limited by a retrospective analysis that includes an inherent bias . non - randomized design may have affected the results because of unmeasured confounders , procedure bias , or detection bias , even with the use of rigorous statistical adjustment .
further , this study represents the experience of a single large tertiary referral center and might not be generalized to other centers .
the outcomes of open surgical repair of dta were feasible in terms of excellent perioperative mortality / morbidity as well as favorable long - term outcomes .
age and lv function were independent predictors of long - term mortality , whereas the surgical strategies did not significantly affect the clinical outcomes .
Output:
| backgroundto determine the predictors of clinical outcomes following surgical descending thoracic aortic ( dta ) repair.methodswe identified 103 patients ( 23 females ; mean age , 64.112.3 years ) who underwent dta replacement from 1999 to 2011 using either deep hypothermic circulatory arrest ( 44% ) or partial cardiopulmonary bypass ( cpb , 56%).resultsthe early mortality rate was 4.9% ( n=5 ) .
early major complications occurred in 21 patients ( 20.3% ) , which included newly required hemodialysis ( 9.7% ) , low cardiac output syndrome ( 6.8% ) , pneumonia ( 7.8% ) , stroke ( 6.8% ) , and multi - organ failure ( 3.9% ) .
none experienced paraplegia . during a median follow - up of 56.3 months ( inter - quartile range , 23.1 to 85.1 months ) , there were 17 late deaths and one aortic reoperation .
overall survival at 5 and 10 years was 80.9%4.3% and 71.7%5.9% , respectively .
reoperation - free survival at 5 and 10 years was 77.3%4.8% and 70.2%5.8% .
multivariable analysis revealed that age ( hazard ratio [ hr ] , 1.10 ; 95% confidence interval [ ci ] , 1.05 to 1.15 ; p<0.001 ) and left ventricle ( lv ) function ( hr , 0.88 ; 95% ci , 0.82 to 0.96 ; p<0.003 ) were significant and independent predictors of long - term mortality . cpb strategy , however , was not significantly related to mortality ( p=0.49).conclusionsurgical dta repair was practicable in terms of acceptable perioperative mortality / morbidity as well as favorable long - term survival . age and lv function were risk factors for long - term mortality , irrespective of the cpb strategy . |
PubmedSumm118760 | ***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: ca19 - 9 is a monosialoganglioside , which is associated with various types of mucinous tumors in the gastrointestinal tract , such as in the pancreas and biliary tract [ 13 ] .
serum ca19 - 9 plays an important role in the diagnosis and prognostication of colorectal , pancreatic , and biliary tract cancers [ 46 ] . in the gastrointestinal tract and ovaries ,
there have been a number of studies suggesting that serum ca19 - 9 level might be a useful marker in diagnosis of benign dermoid cyst . in those studies , large tumor size , bilateral tumor involvement , and tumor torsion
were correlated with serum ca19 - 9 elevation . however , there have been limited reports of ca19 - 9 as a diagnostic marker in ovarian mucinous tumors .
although many gynecologic oncologists are using serum ca19 - 9 level as a preoperative marker in the investigation of women with an ovarian mass , evidence is still insufficient .
in addition , differentiation of malignant tumors from benign tumors will be more challenging if the role of ca125 as a screening tool is controversial in ovarian malignancy .
serum ca125 is frequently elevated in benign conditions , including pregnancy , endometriosis , and pelvic inflammatory disease , as well as in malignant disorders .
moreover , a number of studies suggest that ca125 is not elevated in most primary ovarian mucinous neoplasms [ 1013 ] .
therefore , we investigated the clinical characteristics correlated with serum ca19 - 9 elevation and evaluated the role of serum ca19 - 9 in differentiating benign from borderline or malignant mucinous tumors in the ovaries .
from 2001 to 2011 in hallym medical university hospital , a total of 149 women with pathologically - confirmed primary ovarian mucinous tumors were preoperatively checked for serum ca19 - 9 and ca125 levels . of those ,
all the patients with malignant mucinous tumors were in stage 1 or 2 . among 122 women with pathologically - confirmed benign mucinous cystadenomas in the ovaries ,
the control group was established by 1:2 matching for age to complement the small sample size of borderline or malignant tumors compared to benign tumors .
patients with benign disease in the gastrointestinal tract , such as in the pancreas and gall bladder , and patients with other co - existing malignant tumors , were excluded from the study group .
patient characteristics ( age at operation , parity , and menopause ) , ultrasonographic ( us ) findings of the lesion ( the largest diameter and site of the lesion ) , preoperative level of serum tumor markers ( ca125 and ca19 - 9 ) , and existence of torsion were retrieved from medical records and pathology reports .
the serum level of ca 19 - 9 and ca 125 were determined by radioimmunoassay by using the modular analytics e 170 module ( roche laboratory systems , mannheim , germany ) .
the cut - off values for ca19 - 9 and ca 125 are 37 u / ml and 35 u / ml , respectively .
statistical analyses were performed using spss for windows ( version 18.0 , spss inc . ) .
the hazard ratio ( hr ) and 95% confidence intervals ( ci ) were calculated . for all statistical tests , p value less than 0.05
serum ca19 - 9 was elevated in the ovaries in 16.7% , 56.3% , and 45.5% of benign , borderline , and malignant mucinous tumors , respectively ( table 1 ) .
in contrast , serum ca125 was elevated in only 27.3% of cases with malignant mucinous tumors in the ovaries .
although the mean value of serum ca19 - 9 was not significantly different among histological subtypes ( p=0.774 ) , serum ca19 - 9 was more frequently elevated in borderline or malignant mucinous tumors than in benign tumors ( 57.9% vs. 16.7% , p=0.001 ) .
clinical characteristics in association with serum ca19 - 9 elevation in women with primary ovarian mucinous tumors are described in table 2 .
specifically , the largest diameter of tumor ( 15 cm in us finding ) , serum ca125 elevation , and tumor pathology ( borderline or malignant ) were correlated with elevated serum ca19 - 9 levels .
however , torsion , bilateral involvement of tumor , and other patient characteristics , including parity and menopause , were not correlated with serum ca19 - 9 elevation .
multivariate analysis revealed that tumor pathology ( borderline or malignant ) was the only independent factor for serum ca19 - 9 elevation in primary ovarian mucinous tumors ( odds ratio [ or ] 3.842 , 95% ci 1.27711.558 , p=0.017 ) ( table 3 ) .
interestingly , subgroup analysis in women with normal serum ca 125 level revealed that serum ca19 - 9 elevation was significantly correlated with borderline or malignant tumors than benign ( 12.8% vs. 43.8% , p=0.014 ) ( table 4 ) .
odds ratio for serum ca19 - 9 elevation was 6.3 ( 95% ci 1.43819.648 ) .
in other words , negative predictive value and positive predictive value of ca19 - 9 was 87.2% and 43.8% , respectively , for cancer discrimination in patients with normal ca125 .
ca19 - 9 is a sialylated lewis a antigen , which is associated with mucins in gastrointestinal adenocarcinomas and also is frequently expressed in mucinous tumors in the ovaries .
although ca19 - 9 is recognized as a useful diagnostic marker in various types of mucinous tumors in the gastrointestinal tract ( e.g. , in the pancreas and biliary tree ) , there have been limited reports of ca19 - 9 as a diagnostic marker in ovarian mucinous tumors .
primary mucinous tumors , which account for approximately 1215% of all ovarian tumors , can be subdivided into 2 distinct histogenetic types : the much more common intestinal ( or non - specific ) type and the less common mllerian ( or endocervical ) type .
therefore , ca125 , which is secreted by mainly mllerian origin tissue , can not be a major tumor marker in mucinous tumors of the ovaries .
pathologically , primary ovarian mucinous tumors are classified as benign , borderline ( mucinous tumor of low malignant potential ) , or malignant tumors .
although 75% of primary mucinous tumors are benign , the other 10% and 15% are comprised of borderline and malignant tumors , respectively . according to a recent model for ovarian carcinogenesis
, ovarian neoplasms can be divided into type i and type ii , and each should be considered as a different disease .
type i tumors , including low - grade serous , mucinous , endometrioid , clear cell , and transitional cell carcinomas , are often confined to the ovary at the time of diagnosis , with a stable genome and without tp53 mutations .
in contrast , type ii tumors , including high - grade serous carcinomas , undifferentiated carcinomas , and carcinosarcomas , are more aggressive and genetically highly unstable [ 19,2123 ] .
actually , the behavior of mucinous ovarian carcinoma is different from that of serous ovarian carcinoma . despite a relatively good prognosis in early - stage disease ,
mucinous ovarian cancers are frequently associated with poorer response to platinum / taxane chemotherapies , and poorer survival , compared to serous ovarian cancers [ 2426 ] .
in addition , mucinous borderline ovarian tumors , which are generally characterized as having low malignant potential without obvious stromal invasion , may present with peritoneal implants , lymph node metastases , and recurrence after the resection .
however , in contrast to serous tumors , differential diagnosis of benign from borderline or malignant tumors is more challenging in mucinous tumors because of their typical large size and the great variation in the degree of differentiation of individual tumors .
although magnetic resonance imaging ( mri ) has recently been suggested as a useful diagnostic tool for mucinous borderline or malignant tumors , considering its cost - effectiveness , the role of mri is still questionable [ 3033 ] .
moreover , serum ca 125 level , which is a typical tumor marker in serous - type ovarian cancer , is less frequently elevated in mucinous tumors than in non - mucinous tumors .
therefore , verification of ca19 - 9 as an effective diagnostic marker is important . in our results ,
serum ca19 - 9 was frequently elevated in primary ovarian mucinous tumors . moreover , borderline and malignant mucinous tumors , but not benign mucinous tumors , were significantly associated with serum ca19 - 9 elevation .
it might be natural that serum ca19 - 9 , which is a sialylated lewis a antigen associated with mucins , is frequently elevated in primary mucinous ovarian tumors .
the principal mechanism of the elevation of ca19 - 9 in ovarian cysts is well - documented in a number of studies of mature cystic teratomas .
for instance , ito et al . demonstrated the presence of ca19 - 9 in the bronchial mucosa and glands of ovarian mature cystic teratoma by immunohistochemical staining .
they also revealed the secretion of ca19 - 9 into the cystic cavity of the lesion .
considering to those findings , the leakage of ca19 - 9 from the cystic cavity into the blood stream might be a main mechanism of serum ca19 - 9 elevation .
we can predict that probable conditions of leakage into the blood stream , such as a larger size tumor , bilateral involvement of the tumor , and tumor torsion , may be correlated with serum ca19 - 9 elevation .
several studies have described the clinical characteristics correlated with serum ca19 - 9 elevation in women with primary ovarian mature cystic teratomas .
reported that ca19 - 9 elevation was correlated with larger tumor size and higher rate of ovarian torsion in ovarian mature cystic teratomas .
demonstrated significant correlation between serum ca19 - 9 levels and larger tumor size , although they failed to show a positive relationship between bilateral tumor involvement and serum ca19 - 9 levels .
likewise , cho et al . reported that serum ca19 - 9 elevation was associated with larger tumor size and presence of a fat component in ovarian mature cystic teratomas .
moreover , they suggested that simultaneous elevation of serum ca125 and ca19 - 9 was associated with a higher cancer risk ( p<0.001 ; or : 23.7 ; 95% ci : 8.86363.576 ) than single elevation of serum ca 19 - 9 . in our results , clinical characteristics associated with serum ca19 - 9 were not the bilateral tumor involvement or existence of torsion , but rather larger tumor size , serum ca125 elevation , and tumor pathology ( borderline or malignant ) . in agreement with results of prior studies
, we found that the elevation of serum ca19 - 9 in ovarian mucinous tumors was significantly correlated with larger tumor size , with leakage as a likely mechanism . but more importantly
, we should focus on the fact that tumor pathology ( borderline or malignant ) was the only independent risk factor for serum ca19 - 9 elevation in primary ovarian mucinous tumors ( or 3.842 , 95% ci 1.27711.558 , p=0.017 ) .
subgroup analysis in women with normal serum ca 125 level showed that cancer risk ( borderline ) in women with serum ca19 - 9 elevation is 6.3 times higher than in those with normal serum ca19 - 9 level ( 95% ci 1.43819.648 , p=0.014 ) , which is comparable to results of cho et al . . as previously mentioned , serum ca19 - 9 is a well - recognized tumor marker in diagnosis and in predicting prognosis of various types of mucinous tumors in the gastrointestinal tract .
there is little published evidence of the potential of ca19 - 9 as a preoperative diagnostic tool in ovarian cancer .
, which failed to show a significant correlation between serum ca19 - 9 elevation and histologic subtype of primary ovarian mucinous tumors ( benign 27% vs. borderline 38% vs. malignant 40% , p=0.32 ) .
although they found a weak but statistically significant correlation between tumor size and serum ca19 - 9 level ( spearman s rank correlation coefficient=0.17 , p=0.04 ) , they concluded that serum ca19 - 9 can not be used to predict histologic subtype of mucinous tumors .
serum ca19 - 9 was elevated more frequently in borderline and malignant mucinous tumors , and multivariate analysis revealed that tumor pathology was the only independent correlating factor for serum ca19 - 9 elevation , regardless of tumor size and serum ca125 elevation .
particularly , subgroup analysis in women with normal serum ca 125 level showed that cancer risk ( borderline ) in women with serum ca19 - 9 elevation is 6.3 times higher than in those without elevated levels of ca19 - 9 .
serum ca19 - 9 , which is frequently elevated in primary ovarian mucinous tumors , can be a useful marker in predicting malignancy , particularly when serum ca125 level is not elevated .
this is the first study suggesting a possible role of serum ca19 - 9 in diagnosis of borderline or malignant ovarian tumors , despite several weaknesses , including retrospective design and a small number of subjects . to clarify the diagnostic role of serum ca19 - 9 in discrimination of borderline and malignant tumors from benign mucinous ovarian tumors
Output:
| backgroundthis study was designed to investigate the clinical characteristics correlated with serum ca19 - 9 elevation in primary mucinous ovarian tumors and to evaluate the role of serum ca19 - 9 in predicting borderline or malignant tumors.material/methodswe retrospectively identified 27 women with pathologically - confirmed primary ovarian mucinous neoplasms ( 16 borderline and 11 malignant ) , who had been preoperatively checked for serum ca19 - 9 and ca125 levels .
the control group was established by 1:2 matching for age among all women with pathologically - confirmed benign mucinous tumors over the same time period .
the associations of the serum ca19 - 9 elevation and clinical characteristics , including tumor pathology , were evaluated.resultsserum ca19 - 9 was more frequently elevated in borderline or malignant than benign tumors ( 57.9% vs. 16.7% , p=0.001 ) , although the mean value of serum ca19 - 9 was not significantly different among histological subtypes .
ca19 - 9 elevation was correlated with large tumor size ( largest diameter 15 cm ; p=0.028 ) , serum ca125 elevation ( p=0.006 ) , and tumor pathology ( borderline or malignant tumors ; p=0.001 ) .
other clinical characteristics , including parity , menopause , bilateral tumor involvement , and torsion were not correlated with ca19 - 9 elevation .
multivariate analysis revealed that tumor pathology was the only independent factor for ca19 - 9 elevation in primary ovarian mucinous tumors ( odds ratio 3.842 , 95% ci 1.27711.558 , p=0.017 ) .
interestingly , subgroup analysis in women with normal serum ca 125 level revealed that ca19 - 9 was significantly correlated with borderline and malignant tumors but not with benign tumors ( odds ratio 6.3 , 95% ci 1.43819.648 , p=0.014).conclusionsserum ca19 - 9 can be a useful complementary marker in differentiating benign from borderline or malignant mucinous tumors in the ovaries , particularly when serum ca125 level is not elevated . |
PubmedSumm118761 | ***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 large number of clinical situations playing the role of forerunners within the pathology of the dental - maxillary apparatus was inappropriately assessed in the past and this situation extended nowadays .
the establishing of medical diagnoses by the dentist is often completed subsequent to an evaluation of the dental status without including the dental and facial aspect through which the dysfunction and aesthetic issues interpenetrate . by observing the new requirements related to the orodental therapy with a preventive orientation a proper concept of diagnosis assessment shall be therefore presented .
it includes , except for the basic diagnosis , guidelines regarding the detailed study of the clinical examination and the association , at the same time , for the purpose of elaborating an extended diagnosis which should include the options and the aesthetic reassessment .
the clinical study was carried out within the occlusology clinic of craiova university of medicine and pharmacy during the period 2009 - 2010 and was founded on the assessment of patients according to a proper clinical protocol which permitted the diagnosis and treatment as well as the final dental - facial reassessment . for an accurate determination of inter - maxillary relations
the ultrasonic system has been used therein based on the measuring of the time traversed by sonic waves for a 3d measurement of mandibular movements in all 6 degrees .
the assessment of occlusal integration as regards prosthetic constructions has been carried out by means of protar 7 articulator .
deviations from normal craniomandibular relations encounter a complex aetiology and pathology which involves several factors acting at the level of different elements of the stomatognate system resulting in the modification of common reference frames which actually defines these relations .
the dental occlusion accomplishes the role of stabilizing the mandible in its positions towards the cranium therefore participating at the fulfilment of some systemic functions .
the occlusal disorders arise as a consequence of dental anomalies related to number , volume , position of coronary odontal lesions , dental migrations , edentation , modifications of occlusal parameters , inappropriate prosthetics but it may also result , within a subsidiary plane , due to muscular and articulatory dysfunctions ( fig.1 - 4 ) .
it is revealed under the form of premature contacts ( which characterize the static stages of the occlusion ) , occlusal interferences ( within the mandible dynamics with dental contact ) , localized abrasion ( at the level of a tooth or of a group of teeth which take over the occlusal load ) or generalized for the entire arch .
any occlusal contact which prevents the uniform coaptation of support areas and of occlusal contact points is known as premature occlusal contact .
the premature occlusal contact appears in static occlusion ( at the end of the occlusion terminal trajectory ) , or in dynamic occlusion in the event the mandible movement trajectory interferes with dental contact .
the traumatogenic capacity of a contact point depends on several factors such as : localization of the contract point , the size of the contact point , the condition of the contact surfaces .
therefore , the surface of a contact point is all the more extended as the friction force increases as well as its pathogen potential at the same time .
a reduced contact point in terms of the surface involved but achieved between two rugous surfaces could be as traumatogenic as a contact point extended on a well polished surface due to the increased friction coefficient or it could even be capable of producing more injuries .
contacts could be multiple and symmetrical keeping the mandible in a close or almost identical position with the central relation or with the intercuspidal position without causing anterior , posterior or side deviations .
this happens very rarely as the presence of limited occlusion contracts creates a phenomenon known as occlusal instability .
the clinical assessment of the static and dynamic occlusion can not be performed without a registration of craniomandibular relations .
therefore the registration permits the control , assessment and bringing out of premature contacts and occlusal interferences by means of study patterns ( fig.5 , 6 ) tracking down premature contacts by means of study patterns . marking out of premature contacts on the study pattern . while trying to establish the maximum intercuspidal contact ( for patients with long - centric occlusion ) or the centric occlusion ( for point - centric patients ) , the mandible departs from the rest position rising towards the maxillary under the action of raiser muscles .
the trajectory completed by the mandible between the posture position and the maximal intercuspidal position is known as terminal posture trajectory and the closing trajectory in centric occlusion is called centric terminal trajectory . as far as the disorders of the stomatognate system are concerned this trajectory is interfered , in its final part , by premature contacts or interference contacts or occlusal interferences . during the clinical examination the stages regarding the assessing of muscular function , the presence of articular noises , the mandible mobility on vertical and horizontal planes should be included on a mandatory basis supplemented by signs generated by overstressing at the level of hard and mild tissues .
the marking overjet releases the mandible movements while the tight overjet is seen as an occlusal stress factor . within the craniomandibular malrelations
the overbite frequently appears modified by the existence of a primary deep occlusion or acquired subsequent to the loss of side support .
various combinations of the two elements controlling the frontal occlusion may generate more or less traumatogenic effects . the analysis of the dynamic occlusion is carried out within some test movements transmitted to the mandible as well as during mastication , phonation and deglutition movements .
the analysis of test movements ( retrusion , protrusion , right and left laterality ) often reveals the presence of some occlusal blocks or of some traumatic sliding gradients . the retrusion movement performed between the maximal intercuspidal position and the centric relation could be blocked by some premature contacts therefore impeding the path of the mandible towards the centric relation during deglutition . during the protrusion movement
the premature contact points from lateral area appear on distal gradients of mandibular lateral incisors and on mesial gradients of maxillary cuspids .
the occlusal interference resulted on this path of the mandibular movement reveals an emphasized pathogen potential by the fact that the duration of occlusion contacts and the force intensity are extremely high .
when there is a severe dysfunction the patient interposes his tongue between arches in order to reduce the occlusal trauma during deglutition process .
the protrusion might register premature contacts within the lateral zone which would further prevent the anterior guide of the occlusion on the retroincisive gradient .
the premature contact points belonging to the anterior zone in the protrusion impede the balanced contact of the entire frontal group during teeth movement guide , therefore determining an overloading of the teeth which maintains the contact .
the disorders at the level of occlusal parameters characterized by the shortening and interruption of occlusal areas , their inappropriate artificial or mixed execution , discontinuities , incorrect reinstatements of the retroincisive gradient , modifications of the integrity and form of the support and guide cuspid teeth , changed occlusion curves , the subsided occlusal plane represent important factors of the occlusal dysfunction resulting in modifications of mandibular patterns related to dynamics with consequences at the level of muscular and articular system while taking into account the role of dental determinant within the achievement of mandibular dynamics .
the association of these data with deviations from appropriate statics and the functional disorders at the level of the axial skeleton , especially the of the cervical spine could generate functional errors of associated muscularity ; it is accompanied , in turn , by errors related to the functionality of antagonist masticator muscles .
the assessment protocol of the aesthetic status has also included , besides the determination of the vertical symmetry axis of the horizontal planes and the bipupilar line ( bp ) the plane of commissures of the buccal orifice , the frontal occlusal plane and the facial profile .
also , the locating and assessing of the contact points , contact surfaces , papillas and gingival level has also been taken into account ( 7 - 10 ) .
besides the above mentioned , the study was also intended on the evaluation of dental morphology which comprised the determination of dental axes , the length and width of teeth as well as the determination of the specific chromatic spectrum for each tooth or groups of teeth .
their association with the facial study alongside with the assessment of the cosmetic status , imposed by the patient in this case but improvable or not through suggestions of the dentist , represents the completion of a thorough clinical examination and the commencement of a new protocol for assessment and prosthetic treatment .
1 . the registration of intermaxillary relations on a mandatory basis and their transfer on the articulator shall impose as a unique solution for the appropriate execution of gnato - prosthetic devices . 2 .
the modifications of the form of support and guide cuspid teeth , the occlusion curves and the occlusion plane represent important factors of the occlusal dysfunction resulting in modifications of mandibular patterns related to dynamics .
4 . the deviations from normal statics and functional disorders at the level of axial skeleton especially of the cervical spine could generate functional errors of associated muscularity ; it is accompanied , in turn , by errors related to the functionality of antagonist masticator muscles .
the association of the aesthetic examination to the clinical examination represents an essential condition with a view to achieve the functional reconstruction .
Output:
| the functional disorders of the masticator apparatus impose the accomplishment of a phased assessment protocol which should permit the marking out and prefigure the future treatment plan , at the same time .
the association of clinical data with therapeutic options and last but not least with the patient s expectations represent a particularly important stage within the final occlusal and aesthetic integration . in order to analyse the data collected through examination various assessment systems are available nowadays which permit the correlation of symptoms identified with adequate diagnoses .
the planning of the therapy on the basis of clinical registrations associated with the challenges of the bio - aesthetics shall impose a new conduct within the orofacial rehabilitation of patients . |
PubmedSumm118762 | ***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 ectrodactyly - ectodermal dysplasia cleft lip / palate ( eec ) syndrome is a rare autosomal dominant genetic syndrome characterized by various degrees of ectrodactyly and syndactyly ( hands and feet ) , cleft lip and/or palate and ectodermal dysplasia .
usually it is associated with renal malformations , deafness , mental retardation , and cloacal atresia .
a great majority of the classic eec syndrome cases are due to heterozygote mutations on the p63 gene .
the prenatal diagnosis is usually confirmed by two - dimensional ultrasonography ( 2dus ) , that demonstrates the classic extremity malformations , such as the lobster - claw hands and face ( cleft lip and/or palate ) , frequently associated with urinary tract malformations the three - dimensional ultrasonography ( 3dus ) have been used to analyze the ectrodactyly cases nonetheless , the classic form of eec syndrome has been reported only once in literature .
we present a case of eec syndrome diagnosed on the 19 week of pregnancy in a mother , a carrier of the classic form , in whom the 2dus showed the characteristic extremity and face malformations .
the 3dus allowed a spatial analysis of the malformations , specially the lobster - claw hands .
primigravid woman , 25-year - old , had her first obstetric transvaginal ultrasonography , in which she was confirmed to have a singleton embryo with the crow - rump length ( crl ) of 21 mm , compatible with the 9,0 weeks of gestation .
second ultrasonography , by transvaginal route , was performed on the 11 week that showed a fetus with crl of 47.0 mm , nuchal translucency of 1.3 mm , hands and feet were poorly defined ; at this time eec syndrome was suspected .
2dus was able to demonstrate a fetus with lobster - claw hands ( absence of the 2 and 3 fingers ) , left foot with the absence of the 3 toes and a right foot with syndactyly on the 2 and 3 toes , and presence of a cleft lip / palate .
the 3dus , done with a convex volumetric transductor ( rab 4 - 8l ) of voluson 730 pro machine ( general electric medical systems , healthcare , zipf , austria ) in rendering mode , showed the spatial relations of all malformations of the extremity and face , specially the lobster - claw hands [ figures 1 , 2 and 3 ] .
the 3dus was not essential to the eec syndrome diagnosis , however , it allowed a better depiction of the abnormalities and it was very helpful in explaining the abnormalities to the parents and for genetic counseling .
the prenatal care was uneventful , the delivery was done by caesarian section on the 39 week , and the newborn female with weight of 3,150 g and apgar score 9/9 was born .
three - dimensional ultrasound in rendering mode demonstrates the lobster - claw hands ( white arrow ) .
three - dimensional ultrasound in rendering mode demonstrates the lobster - claw feet ( white arrows ) .
three - dimensional ultrasound in rendering mode demonstrates the left cleft lip ( white arrow ) .
the term eec syndrome was first used by rdiger et al . , to describe a girl with trimelic ectrodactyly , ectodermal dysplasia of hair , teeth , and nails , and also harelip facial cleft .
the eec syndrome has many phenotypic variability and may be associated with thin skin , with hyperkeratosis and nipple hypoplasia .
the ophthalmologic abnormalities are also frequent , varying from blue iris , blepharitis , and dacryocystitis to corneal perforation .
the eec syndrome should be differentiated from the other syndromes that have ectodermal dysplasia and facial clefts such as : rapp - hodgkin syndrome , the hay - wells syndrome , ankyloblepharon ectodermal and harelip facial cleft ; the split - hand and foot malformation syndrome ( shfm ) , syndactyly
median clefts of hands and feet and aplasia / hypoplasia of the phalanges , metacarpals and metatarsals .
haratz - rubinstein et al . , described a case of prenatal diagnosis of shfm at 18 weeks of pregnancy . in this case , the fetus presented with both hands with limited mobility than expected and the thumbs were fixed in an abducted position .
the right hand had a median cleft with fusion of second and third fingers . the pregnant woman had pain and vaginal bleeding at 19 weeks , and she developed inevitable abortion .
the post - mortem skeletal x - ray proved the anomalies detected by prenatal ultrasound .
the second and most common form of this disorder , designated eec3 , is caused by a mutation in the tp63 gene .
the precise prenatal diagnosis is possible by dna extraction by chorionic villus sample done between the 11 and 14 week of pregnancy . in our specific case ,
the prenatal diagnosis of eec syndrome can be done early by the 2dus , when the hands and feet malformations are associated with a cleft lip and/or palate deformities .
the 3dus in the rendering mode has been used to better define the malformations , this mode is better to explain the malformations to the parents .
there are evidences of benefits of 3dus in isolated cases of ectrodactyly , however there is only one image based report related to the eec syndrome in the literaure .
allen and maestri described a case of eec syndrome , similar to ours , diagnosed by 2dus on the 17 week of gestation in a high - risk pregnant woman .
the 2dus showed a cleft palate associated with bilateral ectrodactyly and lobster - claw anomaly of hands and feet .
the 3dus in the rendering mode allowed a proper view of facial anomalies and ectrodactyly of hands . in the absence of other anomalies such as ophthamolical or genito - urinary abnormalities ,
the postnatal prognosis is excellent , with the majority of the subjects presenting with normal intelligence and normal life style after the correction of the face and extremity anomalies .
in summary this is the second case of eec syndrome diagnosed with 3dus in prenatal period .
2dus is sufficient for the diagnosis of eec and 3dus is not essential for its diagnosis .
Output:
| the eec syndrome is a genetic anomaly characterized by the triad : ectodermal dysplasia ( development of anomalies of the structures derived from the embryonic ectodermal layer ) , ectrodactyly ( extremities , hands and feet malformations ) and cleft lip and/or palate ; these malformations can be seen together or in isolation .
the prenatal diagnosis can be made by two - dimensional ultrasonography ( 2dus ) that identifies the facial and/or limb anomalies , most characteristic being the lobster - claw hands .
the three - dimensional ultrasonography ( 3dus ) provides a better analysis of the malformations than the 2dus .
a 25-year - old primigravida , had her first transvaginal ultrasonography that showed an unique fetus with crow - rump length of 47 mm with poorly defined hands and feet , .
she was suspected of having sporadic form of eec syndrome .
the 2dus performed at 19 weeks confirmed the eec syndrome , showing a fetus with lobster - claw hands ( absence of the 2nd and 3rd fingers ) , left foot with the absence of the 3rd toe and the right foot with syndactyly , and presence of cleft lip / palate .
the 3dus defined the anomalies much better than 2dus including the lobster - claw hands . |
PubmedSumm118763 | ***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: isolated internal iliac artery aneurysms are very rare , accounting for around 0.4% of abdominal aneurismal disease ( 1 ) . with a rupture rate of 38% and associated high mortality , early detection and intervention
signs and symptoms at presentation are often nonspecific so a high index of clinical suspicion is required .
timely intervention in cases of isolated internal iliac artery aneurysm has the potential to improve survival .
an 84 year old , retired electrician , presented to the emergency department with reduced urine output and lower abdominal pain .
he reported a three day history of urinary hesitancy and increased frequency , associated with generalised lower abdominal pain radiating to the testes .
his medical history included transurethral resection of the prostate in 2005 , inguinal hernia repair and hypertension .
the patient lived alone and was an ex - smoker . on examination he appeared well , with stable observations .
he was noted to have lower abdominal tenderness , without being peritonitic , and had a palpable bladder .
a provisional working diagnosis of urinary retention was therefore made , with no cause identified .
axial view of ct abdomen - pelvis showing right internal iliac artery aneurysm with a contained pre - sacral leak ( as indicated by arrow ) the patient deteriorated the following day , becoming hypotensive and anuric , with an increasingly tender abdomen .
after initial resuscitation , an urgent ct scan of the chest , abdomen and pelvis showed an 8.5 cm aneurysm of the right internal iliac artery .
there appeared to be a contained leak from the aneurysm in the pre - sacral region ( fig .
a moderate amount of intraperitoneal free fluid was noted . a right sided hydronephrosis with associated right hydroureter was also noted .
an urgent transfer to a vascular facility was arranged and a same day endovascular repair of the aneurysm was performed .
prompt identification of the underlying cause is then essential in directing further management . in elderly men causative factors can be grouped into : obstructive , neurogenic and detrusor inactivity .
benign prostatic hyperplasia is the most common individual cause but often there are multiple underlying factors ( 2 ) .
careful history and examination , combined with the use of specific diagnostic testing will usually establish a cause , and therefore result in the identification of high risk patients ( 3 ) .
iliac artery aneurysms account for an estimated 2% of intra - abdominal aneurysmal disease , with a quarter of these primarily affecting the internal iliac artery .
typically presentation is late , with an estimated 40% rupturing and a mortality of over 50% in those cases .
identifying patients with internal iliac artery aneurysms of any size is challenging , because they often remain asymptomatic .
patients may present with non specific symptoms of abdominal pain and tenderness , or symptoms and signs of local compression .
this case demonstrates how a rare and potentially life threatening aneurysm manifested as a relatively common presentation abdominal pain and urinary retention .
it is likely that the patient s urinary symptoms were caused by local compression exerted by the aneurysm and its subsequent rupture .
a triad of symptoms abdominal pain , urinary retention and haemodynamic instability , prompted the clinician to request urgent imaging thus allowing early intervention and a good outcome .
the importance of considering a broad range of differential diagnoses is clearly demonstrated particularly when more common causes are less likely .
this patient had already undergone a turp making a prostatic cause of retention less probable .
aneurysmal dilation and rupture ought to be among any clinicians differential diagnosis for urinary retention , especially in the context of progressive symptoms in an acutely deteriorating , unstable patient .
there are a number of case reports on the various different presentations of iliac artery aneuryms : lumbrosacral plexopathy , bowel obstruction and a case of a patient presenting with cullen s sign .
these varied presentations collectively demonstrate the difficultly in swift diagnosis of an internal iliac artery aneurysm with potential associated rupture ( 5 - 8 ) .
the presenting problem in this case report and of those reviewed remains consistent urinary retention and abdominal discomfort .
haemodynamic instability , as seen in this case , is another indicator that the underlying diagnosis may be vascular in origin .
we propose that any patient presenting acutely with urinary retention , abdominal pain and haemodynamic instability should qualify for an urgent ct abdomen in order to rule out an iliac artery aneurysm .
this case emphasises the importance of maintaining a broad and open mind in approach to the management of urinary retention associated with other symptoms , and reacting quickly to clinical developments .
Output:
| internal iliac artery aneurysms are rare , but with a mortality approaching 50% in those that rupture , prompt diagnosis is essential . often presentation is nonspecific ; a wide variety of symptoms and signs have been encountered , illustrating a challenge in identification .
we report a case of ruptured internal iliac artery aneurysm presenting as urinary retention .
the importance of maintaining a broad differential in cases of urinary retention is clearly highlighted . |
PubmedSumm118764 | ***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: within eukaryotic cells , endosomes are key sorting stations that receive material ( proteins and lipids ) from both the biosynthetic and the endocytic pathways . a membrane protein arriving at an endosome
can be sorted for delivery to one of three destinations : the cell surface , the golgi , and the lysosome .
the retromer complex is a conserved multimeric protein complex that is required to sort proteins into both the endosome - to - golgi , and endosome - to - cell surface pathway .
the role of cargo selection within retromer is performed by a trimer of the vps35 , vps26 , vps29 proteins where binding to cargo is known to be mediated by both vps35 and vps26 .
the other key activity of retromer is membrane bending to form tubules into which cargo is sorted .
tubules are formed by the action of the sorting nexin ( snx ) dimer component of retromer , which associates loosely with the trimeric cargo - selective complex ( csc ) .
the snx dimer binds to phosphatidyl inositol 3-phosphate ( ptdins 3p ) in the membrane and is able to generate tubules through an intrinsic self - assembly activity and the action of c - terminal bin - amphiphysin - rvs ( bar ) domains that adopt a curved banana - shaped conformation to drive tubulation .
the snx1 protein is a key element of retromer - mediated endosomal protein sorting and can generate membrane tubules both in vivo and in vitro .
in addition to mediating sorting of membrane proteins into nascent tubular domains for delivery to the golgi or the cell surface , the retromer csc also functions as a hub for recruiting a host of accessory proteins to endosomes . a key retromer accessory is the wash complex a pentameric protein complex that mediates production of filamentous ( f- ) actin patches on endosomes to facilitate the partitioning of membrane protein into discrete regions of the endosome so that sorting into distinct pathways is accomplished .
loss of wash complex function results in an accumulation of endosomal tubules indicating that the wash complex contributes to the scission of tubules , possibly through an association with dynamin-2 .
the recruitment of the wash complex to endosomes occurs through the interaction of the vps35 protein with the extended tail domain of the fam21 protein of the wash complex . along with binding to the wash complex
, vps35 also interacts with a protein called fkbp15 ( also known as fkbp133 and wafl ) .
thus a tripartite complex comprising the retromer csc , the wash complex , and fkbp15 is formed .
the precise role of fkbp15 has yet to be determined but it may function to modulate actin dynamics at the endosome .
the retromer cargo - selective complex ( csc ) associates with endosomal membranes to sort cargo proteins ( e.g. the cation - independent mannose 6-phosphate receptor cimpr ) into tubules formed by the sorting nexin ( snx ) dimer .
the retromer csc also recruits the wash complex that mediates f - actin production through vps35 binding to the extended tail of the fam21 protein ( shown in pink ) .
the rme-8 protein has recently been shown to associate with the wash complex through binding to fam21 and regulates the kinetics of snx dimer association - dissociation with the membrane .
the sorting nexin dimer , including the snx1 protein , also associates with accessory factors ; one of which is a protein called rme-8a member of the dnaj family of proteins that are implicated in regulating the assembly and disassembly of macromolecular complexes via an interaction with chaperone proteins . in a recent publication , it has been shown that rme-8 also associates with the wash complex through binding to the tail of the fam21 protein .
when rme-8 expression was abolished using rnai , the morphology of endosomes was profoundly altered becoming a highly branched network of membrane tubules that contained many membrane proteins that require retromer and the wash complex for their proper localization including the iron transporter protein slc11a2 ( also known as dmt1-ii ) and the 51 integrin complex .
proteins that comprise the retromer csc , i.e. , vps26 and vps35 , also became extensively localized to tubules , as did the snx1 protein .
the knockdown of rme-8 leads to an accumulation of endosomal tubules that are positive for retromer proteins and cargo such as the cimpr .
it was hypothesised that the increase in membrane tubules observed after loss of rme-8 function may be due , at least in part , to reduced kinetics of snx1 association and dissociation with the membrane .
this was investigated using fluorescence recovery after photobleaching ( frap ) experiments that confirmed that the kinetics of snx1 association with the membrane were altered so that the recovery of gfp - snx1 fluorescence was markedly slower after loss of rme-8 expression .
the precise role of rme-8 in modulating the activity of the wash complex has yet to be elucidated but it is possible that rme-8 functions to regulate the localization of the wash complex so that the wash complex is primarily localized to vesicular endosomes and not tubules as the function of the wash complex to promote f - actin production is required on vesicular endosomes to facilitate sorting of membrane proteins .
consistent with this hypothesis , the fam21 protein and a gfp - tagged wash1 protein become localized to endosomal tubules following sirna - mediated silencing of rme-8 .
interestingly , the dnajc13 gene that encodes rme-8 has recently been shown to be mutated in an inherited form of parkinson disease ( pd ) .
it is not currently known whether the pd - causing mutation affects the association of rme-8 with either the wash complex or snx1 but this may be a fruitful area to investigate .
the identification of dnajc13/rme-8 as a player in pd cements the importance of endosomal protein sorting in the pathogenesis of pd and follows the identification of vps35 as a pd gene . for vps35 ,
the pd - causing mutation is a substitution of aspartate for asparagine at residue 620 ( d620n ) .
this mutation has now been shown to impair the association of the wash complex with the retromer csc resulting in reduced wash complex recruitment to the endosome .
thus the fam21 protein of the wash complex interacts with two proteins vps35 and rme-8both of which are mutated in pd .
this suggests that wash complex function may be especially important in the mechanisms that underlie pd .
in fact , wash complex function is already associated with another neurodegenerative movement disorder , namely hereditary spastic paraplegia ( hsp ) , as the strumpellin component of the wash complex is encoded by the kiaa0196 gene at the spg8 locus a locus associated with hsp .
currently it is not known why mutations in strumpellin cause hsp whilst mutations to wash complex - associated proteins result in pd .
curiously , although the retromer - wash complex association is impaired by the vps35 pd mutation , the most pronounced effect of the vps35 d620n mutation is on the association with fkbp15 , a protein whose role in endosomal protein sorting remains poorly understood .
one role of the fkbp15 protein may be to facilitate or stabilize the retromer - wash complex association as increased fkbp15 expression can enable retromer to co - immunoprecipitate the wash complex under less favourable conditions .
indeed when fkbp15 is overexpressed , in a subset of highly expressing cells , it forms cytoplasmic aggregates that contain both the wash complex and rme-8 ( see fig .
3 ) indicating that fkbp15 forms a strong association with the wash complex and can exert dominant negative effects on wash - complex associated proteins such as rme-8 .
the fkbp15 protein is linked to inflammatory bowel disease but it is currently not known what role fkbp15 plays in this disease .
cells were transiently transfected with mcherry - tagged fkbp15 . in the highly expressing cells fkbp15 forms bright cytoplasmic aggregates that are also positive for wash complex proteins and rme-8 .
scale bar = 20 m . among the pd - causing genes , mutations in lrrk2
it has recently been reported that overexpression of wildtype vps35 could rescue lysosomal defects caused by lrrk2 mutants but the vps35 d620n mutant does not rescue suggesting that retromer function is possibly downstream of lrrk2 activity .
interestingly , it has been reported that the loss of lrrk2 function can also cause inflammatory bowel disease although it is mechanistically unclear how this occurs . as both lrrk2 and
fkbp15 have been linked to inflammatory bowel disease and both are players in pd ( fkbp15 through the vps35 d620n mutant ) it is tempting to speculate that a common mechanism or pathway involving fkbp15 and lrrk2 underlies both pathologies .
within eukaryotic cells , endosomes are key sorting stations that receive material ( proteins and lipids ) from both the biosynthetic and the endocytic pathways . a membrane protein arriving at an endosome
can be sorted for delivery to one of three destinations : the cell surface , the golgi , and the lysosome .
the retromer complex is a conserved multimeric protein complex that is required to sort proteins into both the endosome - to - golgi , and endosome - to - cell surface pathway .
the role of cargo selection within retromer is performed by a trimer of the vps35 , vps26 , vps29 proteins where binding to cargo is known to be mediated by both vps35 and vps26 .
the other key activity of retromer is membrane bending to form tubules into which cargo is sorted .
tubules are formed by the action of the sorting nexin ( snx ) dimer component of retromer , which associates loosely with the trimeric cargo - selective complex ( csc ) .
the snx dimer binds to phosphatidyl inositol 3-phosphate ( ptdins 3p ) in the membrane and is able to generate tubules through an intrinsic self - assembly activity and the action of c - terminal bin - amphiphysin - rvs ( bar ) domains that adopt a curved banana - shaped conformation to drive tubulation .
the snx1 protein is a key element of retromer - mediated endosomal protein sorting and can generate membrane tubules both in vivo and in vitro .
in addition to mediating sorting of membrane proteins into nascent tubular domains for delivery to the golgi or the cell surface , the retromer csc also functions as a hub for recruiting a host of accessory proteins to endosomes . a key retromer accessory is the wash complex a pentameric protein complex that mediates production of filamentous ( f- ) actin patches on endosomes to facilitate the partitioning of membrane protein into discrete regions of the endosome so that sorting into distinct pathways is accomplished .
loss of wash complex function results in an accumulation of endosomal tubules indicating that the wash complex contributes to the scission of tubules , possibly through an association with dynamin-2 .
the recruitment of the wash complex to endosomes occurs through the interaction of the vps35 protein with the extended tail domain of the fam21 protein of the wash complex . along with binding to the wash complex
, vps35 also interacts with a protein called fkbp15 ( also known as fkbp133 and wafl ) .
thus a tripartite complex comprising the retromer csc , the wash complex , and fkbp15 is formed .
the precise role of fkbp15 has yet to be determined but it may function to modulate actin dynamics at the endosome .
the retromer cargo - selective complex ( csc ) associates with endosomal membranes to sort cargo proteins ( e.g. the cation - independent mannose 6-phosphate receptor cimpr ) into tubules formed by the sorting nexin ( snx ) dimer .
the retromer csc also recruits the wash complex that mediates f - actin production through vps35 binding to the extended tail of the fam21 protein ( shown in pink ) .
the rme-8 protein has recently been shown to associate with the wash complex through binding to fam21 and regulates the kinetics of snx dimer association - dissociation with the membrane .
the sorting nexin dimer , including the snx1 protein , also associates with accessory factors ; one of which is a protein called rme-8a member of the dnaj family of proteins that are implicated in regulating the assembly and disassembly of macromolecular complexes via an interaction with chaperone proteins . in a recent publication , it has been shown that rme-8 also associates with the wash complex through binding to the tail of the fam21 protein . when rme-8 expression was abolished using rnai ,
the morphology of endosomes was profoundly altered becoming a highly branched network of membrane tubules that contained many membrane proteins that require retromer and the wash complex for their proper localization including the iron transporter protein slc11a2 ( also known as dmt1-ii ) and the 51 integrin complex .
proteins that comprise the retromer csc , i.e. , vps26 and vps35 , also became extensively localized to tubules , as did the snx1 protein .
the knockdown of rme-8 leads to an accumulation of endosomal tubules that are positive for retromer proteins and cargo such as the cimpr .
it was hypothesised that the increase in membrane tubules observed after loss of rme-8 function may be due , at least in part , to reduced kinetics of snx1 association and dissociation with the membrane .
this was investigated using fluorescence recovery after photobleaching ( frap ) experiments that confirmed that the kinetics of snx1 association with the membrane were altered so that the recovery of gfp - snx1 fluorescence was markedly slower after loss of rme-8 expression .
the precise role of rme-8 in modulating the activity of the wash complex has yet to be elucidated but it is possible that rme-8 functions to regulate the localization of the wash complex so that the wash complex is primarily localized to vesicular endosomes and not tubules as the function of the wash complex to promote f - actin production is required on vesicular endosomes to facilitate sorting of membrane proteins .
consistent with this hypothesis , the fam21 protein and a gfp - tagged wash1 protein become localized to endosomal tubules following sirna - mediated silencing of rme-8 .
interestingly , the dnajc13 gene that encodes rme-8 has recently been shown to be mutated in an inherited form of parkinson disease ( pd ) .
it is not currently known whether the pd - causing mutation affects the association of rme-8 with either the wash complex or snx1 but this may be a fruitful area to investigate .
the identification of dnajc13/rme-8 as a player in pd cements the importance of endosomal protein sorting in the pathogenesis of pd and follows the identification of vps35 as a pd gene . for vps35 ,
the pd - causing mutation is a substitution of aspartate for asparagine at residue 620 ( d620n ) .
this mutation has now been shown to impair the association of the wash complex with the retromer csc resulting in reduced wash complex recruitment to the endosome .
thus the fam21 protein of the wash complex interacts with two proteins vps35 and rme-8both of which are mutated in pd .
this suggests that wash complex function may be especially important in the mechanisms that underlie pd .
in fact , wash complex function is already associated with another neurodegenerative movement disorder , namely hereditary spastic paraplegia ( hsp ) , as the strumpellin component of the wash complex is encoded by the kiaa0196 gene at the spg8 locus a locus associated with hsp .
currently it is not known why mutations in strumpellin cause hsp whilst mutations to wash complex - associated proteins result in pd .
curiously , although the retromer - wash complex association is impaired by the vps35 pd mutation , the most pronounced effect of the vps35 d620n mutation is on the association with fkbp15 , a protein whose role in endosomal protein sorting remains poorly understood .
one role of the fkbp15 protein may be to facilitate or stabilize the retromer - wash complex association as increased fkbp15 expression can enable retromer to co - immunoprecipitate the wash complex under less favourable conditions .
indeed when fkbp15 is overexpressed , in a subset of highly expressing cells , it forms cytoplasmic aggregates that contain both the wash complex and rme-8 ( see fig .
3 ) indicating that fkbp15 forms a strong association with the wash complex and can exert dominant negative effects on wash - complex associated proteins such as rme-8 .
the fkbp15 protein is linked to inflammatory bowel disease but it is currently not known what role fkbp15 plays in this disease .
cells were transiently transfected with mcherry - tagged fkbp15 . in the highly expressing cells fkbp15 forms bright cytoplasmic aggregates that are also positive for wash complex proteins and rme-8 .
scale bar = 20 m . among the pd - causing genes , mutations in lrrk2
it has recently been reported that overexpression of wildtype vps35 could rescue lysosomal defects caused by lrrk2 mutants but the vps35 d620n mutant does not rescue suggesting that retromer function is possibly downstream of lrrk2 activity .
interestingly , it has been reported that the loss of lrrk2 function can also cause inflammatory bowel disease although it is mechanistically unclear how this occurs .
as both lrrk2 and fkbp15 have been linked to inflammatory bowel disease and both are players in pd ( fkbp15 through the vps35 d620n mutant ) it is tempting to speculate that a common mechanism or pathway involving fkbp15 and lrrk2 underlies both pathologies .
the retromer and wash complexes play key roles in endosomal protein sorting and are emerging as cellular machinery that is especially important in many neurological diseases , including pd .
the convergence of genetic studies identifying disease - causing mutations with the functional studies of endosomal protein sorting represents a significant advance in understanding the molecular basis of diseases such as pd , but there is much left to learn about how the various proteins operate in endosomal protein sorting and what consequences arise when these processes are perturbed .
the next few years offer the potential for further advances that will illuminate both the pathology of pd and also the basic mechanisms of endosomal protein sorting .
Output:
| the retromer complex mediates endosomal protein sorting by concentrating membrane proteins ( cargo ) into nascent tubules formed through the action of sorting nexin ( snx ) proteins .
the wash complex is recruited to endosomes by binding to the vps35 subunit of retromer and facilitates cargo protein sorting by promoting formation of endosomally - localized f - actin .
the vps35 protein is mutated in parkinson disease ( pd ) and a recent report has revealed that the pd - causing mutation impairs the association of retromer with the wash complex leading to perturbed endosomal protein sorting . another important player in endosomal protein sorting is the dnajc13/rme-8 protein , which associates with snx1 and has also recently been linked to pd . an additional recent report has now shown that rme-8 also interacts with the wash complex thus establishing retromer and wash complex - mediated endosomal protein sorting as a key pathway linked to the pathology of pd and providing new avenues to explore in the search for insights into the disease mechanism . |
PubmedSumm118765 | ***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: diabetic retinopathy is the commonest cause of blindness in patients of working age in developed countries , principally due to the complications of neovascularization , or to maculopathy ( focal or diffuse macular edema).1,2 although considerable progress has been made in reducing the incidence of blindness through improved medical control , screening , and timely laser therapy,36 many patients with maculopathy are either relatively resistant to photocoagulation , or develop recurrent edema , with consequent visual deterioration despite undergoing repeat laser therapy.7 reported outcomes from vitreoretinal surgery for macular edema have been relatively disappointing , with the risk of sight - threatening side effects arising from such a complex procedure.8,9 intravitreal steroids and anti - vascular endothelial growth factor ( anti - vegf ) preparations are increasingly employed , but there is also a recognized morbidity and a requirement for repeated injections.10,11 it is likely that the pathogenesis of diabetic macular edema is due to a complex interaction of a number of factors , and these include vitreoretinal relationships at the macula . specifically , it seems that an attached vitreous may tend to sustain or exacerbate edema , while conversely a posterior vitreous detachment ( pvd ) may ameliorate existing retinopathy.12,13 these observations provided the rationale for the current study , whereby a technique of intravitreal gas injection was employed to evaluate its effect on diabetic macular edema through the induction of a pvd .
a detailed protocol was submitted to and agreed by the local ethics committee . all patients provided fully informed consent before enrolment in the study .
inclusion criteria were : medically diagnosed diabetes ( type i or ii ) ; clinically significant macular edema ( csmo ) , according to the early treatment diabetic retinopathy study ( etdrs ) guidelines:14 retinal thickening within 500 m of the center of the fovea ; hard , yellow exudates within 500 m of the center of the fovea with adjacent retinal thickening ; at least 1 disc area of retinal thickening , any part of which is within 1 disc diameter of the center of the fovea ; four or more previous macular laser treatments ; no significant macular ischemia on fluorescein angiography ; an attached vitreous ( including vitreomacular traction ) , identified by biomicroscopy and b scan ultrasonography ; no untreated retinal pathology ( retinal breaks , significant degeneration , etc ) .
exclusion criteria were : atrophic macular degeneration ; proliferative diabetic retinopathy ; inability to provide informed consent .
pre - treatment investigations included visual acuity ( etdrs chart ) , biomicroscopy , fluorescein angiography , and optical coherence tomography ( oct ) scanning ( stratus oct , zeiss meditec , jena , germany ) ; mydriasis of the treatment eye was accomplished with cyclopentolate 1% drops .
a volume of 0.3 ml of 100% perfluoropropane ( c3f8 ) gas was then injected into the vitreous cavity at 3.54.0 mm posterior to the limbus via a 27-gauge needle .
topical maxitrol and cyclopentolate 1% drops ( alcon , fort worth , tx ) were prescribed ( and the appropriate hypotensive agent if there was an elevation in intraocular pressure ) , and the patient instructed to posture in a prone position for 40 minutes in each hour for 1 week .
post - treatment evaluation was performed at 1 week , 1 month , 3 months , and 46 monthly thereafter . at each visit ,
color fundus photography was also performed , but fluorescein angiography only if biomicroscopy and oct findings provided insufficient information for an adequate evaluation .
a minimum of 3 months was allowed to gauge the effect of the gas injection .
a pvd was judged to have developed if there was a visible weiss ring and/or posterior hyaloid face ( phf ) .
if there was persistent csmo by 3 months , consideration was given to administering additional therapy ( laser , or intravitreal injection ) .
due to the strict inclusion and exclusion criteria for this study , only five eyes of five patients were recruited over a 2-year period .
all patients had type ii diabetes , with a mean age of 69 ( range 6483 ) and mean review was 18 months ( range 936 ) .
a pvd was induced in all eyes , with unequivocal vitreomacular separation being observed between 1 week and 1 month following injection in all cases .
none of the patients treated had prior vitreomacular traction ( although the efficacy of this method for this condition has been indicated in another publication by the authors.15 signs of reduction in macular thickness and early resorption of exudates were observed by 1 month , with the beneficial trend continuing for 912 months following treatment .
median visual improvement and macular thickness was 11 etdrs letters ( range 421 ) and 157 m respectively ( table 1 and figures 13 ) .
no eyes lost vision over the review period due to persistent or recurrent macular edema . apart from a transient vitreous hemorrhage in one eye at 1 month ( patient 2 , possibly due to minor retinal vascular trauma during vitreous separation ) , there were no significant retinal treatment - related complications . in those eyes which were phakic ,
although no patient required further macular laser therapy over the period of review , one patient ( patient 5 ) developed an area of peripheral neovascularization 9 months following gas injection , and panretinal photocoagulation was performed .
the influence of the vitreoretinal relationship in diabetic macular edema has been long recognized,12,13 and pars plana vitrectomy has been employed to induce a pvd and peel the inner limiting membrane , or any associated epiretinal membrane .
the observed postoperative improvement in macular status has however been mitigated by such side effects as cataract formation , retinal breaks , and retinal detachment.8,9 there are also logistical considerations with this technique in that it requires access to specialized facilities and must be performed by a vitreoretinal specialist . in many regions and countries , there are insufficient resources to allow the ready availability of this form of treatment .
previous studies have commented on the effectiveness of pneumatic retinopexy in inducing a pvd for the treatment of macular holes and in cases of nonproliferative diabetic retinopathy , with consequent beneficial effects on the pathology.16,17 in the current study , the observed resolution of exudates and edema in these refractory cases was remarkable .
although the previous laser treatments might have had some beneficial effect , this may have been counter - acted by persistent vitreoretinal traction , on which laser treatment alone would have had no significant influence .
apart from relief of traction , induction of a pvd may also confer a secondary beneficial effect in increasing retinal oxygenation derived from the fluid phase between the neuroretina and the phf .
an increase in oxygen tension within the inner retina could have a mitigating effect on macular edema by a number of mechanisms : reduced vegf production causing decreased retinal vascular permeability ; autoregulatory arteriolar vasoconstriction reducing hydrostatic pressure in capillaries and venules .
there will be in turn decreased extravascular fluid flow ( the starling equation ) and reduced edema formation.18 one notable feature of the current and of these previous studies utilizing gas injection is the low complication rate and in particular the absence of retinal tear or detachment formation , compared with pars planavitrectromy and indeed pneumatic retinopexy for established retinal detachment.19,20 in comparison with a vitrectomy , the relative safety of gas injection may relate to the gas having a gradual effect in separating the phf from the retina , in the absence of preexisting peripheral retinal pathology ( inducing a more physiological pvd ) .
pneumatic retinopexy for an established retinal detachment confers compressive and tractional forces on vitreous and retina , which are already ( at least partially ) detached and as a consequence , secondary break formation is commonly observed , often at sites diametrically opposed to the original break location .
a different situation is present when gas is injected into an eye where there is no pvd and no preexisting peripheral retinal pathology .
induction of a pvd in this instance is more analogous to the formation of a spontaneous pvd , which is typically associated with a risk of break formation of the order of 10% and a much lower risk of retinal detachment.21 in the current series , the high frequency of clinical review would in any case have identified any fresh retinal break formation , allowing its timely management ( although to date this has not occurred ) .
the low numbers of eyes treated in this series reflects the cautious approach that was taken to a novel application of an established technique in eyes with advanced retinopathy .
the promising results of this pilot series , together with the low complication rate now encourages the establishment of a randomized trial to test further the authors hypothesis and arguably the incorporation of pneumatic retinopexy in combination therapy with laser photocoagulation and intravitreal steroid and anti - vegf injection .
Output:
| purposethis study investigates the efficacy of an intravitreal gas injection in inducing a posterior vitreous detachment ( pvd ) in patients with clinically significant diabetic macular edema refractory to laser therapy.methodsa local ethics committee - approved technique of an intravitreal injection of pure perfluoropropane gas ( c3f8 ) was performed for all participants . after a period of prone positioning
, the patients underwent regular and detailed clinical review.main outcome measuresthe induction of a pvd , change in macular thickness , change in visual acuity.resultsa pvd was induced in all five eyes with subsequent signs of reduction in macular thickness and resolution of exudates .
mean visual improvement was 11 etdrs ( early treatment diabetic retinopathy study ) letters ( range 421 ) .
apart from a transient vitreous hemorrhage in one eye , there were no significant treatment - related complications.conclusionthe induction of a pvd by pneumatic retinopexy appears to have a significant influence on diabetic macular edema in eyes which have not successfully responded to macular laser therapy .
a randomized clinical trial is justified on the basis of the initial promising data . |
PubmedSumm118766 | ***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: nearly everyone has seen negative afterimage illusions , and most textbooks discuss them in the context of trichromatic vision and opponent cells .
this illusion is a good place to start because it introduces adaptation and opponent processes , which have bearing beyond color vision , and is tied to a simple model from which students can make straightforward predictions .
students set the color and duration of adaptation and can time the duration of the afterimage .
questions : ( 1 ) what color of afterimage do you get with each of the adaptation colors ?
( 2 ) what color do you expect to see when viewing cyan after adapting to blue ?
( 3 ) do you predict an afterimage from adaptation to a black image ? ( 4 ) does closing your eyes after adaptation make the afterimage last longer ? ( 5 ) what do you see if , after adaptation , you move your head closer to or further from the white screen or look at the sky ? ( 6 ) if you adapt one eye with the other eye closed and then switch eyes , is there an afterimage ? interpretations :
( 1 ) students should be able to predict the afterimage of any color by using the opponent model .
( 2 ) the opponent model also predicts biasing perception of another color ; after adaptation to blue , any color should appear less blue ( cyan becoming greenish , or magenta becoming redder ) .
( 3 ) the opponent model applies to black and white as well as to colors ; it is also interesting to see a whiter - than - white afterimage on even the brightest background , which seems dingy in contrast .
this also makes the point ( reinforced by the contrast illusions ) that perception of brightness depends on relative rather than absolute values .
( 4 ) eye closing extends the afterimage duration , while blinking may restore a faded afterimage ; i have not yet found a good explanation of this .
( 5 ) when the head moves closer to the screen , the afterimage appears to shrink , while it appears larger when the head is further from the screen or one looks at the sky .
the adapted part of the visual field remains the same size ( visual angle ) , but we interpret that size differently depending on distance cues ; a given visual angle indicates a larger size when its source is distant than when it is near .
( 6 ) in my experience , the negative afterimage does not transfer from one eye to the other .
while color is handled at many levels in the visual system , the first color - opponent cells are found in the lateral geniculate nucleus ( lgn ) , before significant binocular processing .
in addition to these questions , students could do experiments testing the duration of the afterimage under different conditions such as very short or long adaptation periods , different levels of color saturation and so on .
the motion aftereffect , also known as the waterfall illusion , was first described by aristotle .
after one watches motion in one direction , stationary objects appear to move in the opposite direction .
it poses a rich set of questions but is also just plain fun for students .
( project inward - moving concentric circles and then listen for reactions when students look at their hands . ) figure 2 shows an adapting stimulus , after which a mottled or blank screen is presented .
students set the duration , direction , speed , color , contrast , and size of the moving stimulus , and can time the duration of the aftereffect .
questions : ( 1 ) how can you demonstrate the existence of detectors tuned to different directions of motion in the same part of the visual field ? ( 2 ) adapt to downward motion and then view horizontal motion . what do you predict ? ( 3 ) adapt to downward motion and then switch to upward motion ; what do you predict ? ( 4 ) how can you test whether motion detectors are present throughout the entire visual field ?
( 5 ) how could you determine whether motion detection is primarily peripheral ( retina to lgn ) or central ( v1 and up ) ? ( 6 ) what do you see if you adapt to motion and then view a blank surface ? ( 7 ) how do the color and contrast of the adapting stimulus affect the aftereffect ? ( 8) how do the speed of movement and size of the stripes affect the strength of aftereffect ?
interpretations : ( 1 ) the same part of the visual field can respond to , and have aftereffects from , motion in any direction . in principle
, we could detect any direction from the vector sum of four detectors ( right , left , up , down ) .
( 2 ) with downward motion detectors adapted , horizontally moving stripes appear to move diagonally upward .
this suggests that perceived motion is due to the ratio of responses of opposing detectors rather than to the absolute value of any one detector s response .
( 4 ) the aftereffect is strongest at the periphery , with little motion in the center .
. peripheral vision may be specialized to direct attention to moving objects while central vision is specialized for detailed form .
( 5 ) adapt one eye with the other closed , then check for the aftereffect with the adapted eye closed and the rested eye open .
the aftereffect transfers across eyes ( albeit more weakly ) , suggesting that it is due to neurons with binaural input ( primary visual cortex or later ) .
human fmri studies implicate motion - sensitive areas of visual cortex ( area mt ) in the aftereffect ( huk et al . , 2001 ) .
simultaneously present upward movement to the left eye and downward movement to the right eye ; each eye will have an independent negative aftereffect .
( this can be done easily in psycog ; use a piece of cardboard or pair of tubes to prevent each eye from seeing the display intended for the other . ) ( 6 ) the motion aftereffect can be seen even on a blank surface .
it may reflect the processing of motion and form by different pathways in visual cortex .
( 7 ) color has no effect on the strength of the aftereffect , suggesting that motion detection relies on edges defined by luminance .
contrast also has little effect , and even the lowest - contrast moving stripes can give a robust aftereffect .
i have not found a good explanation for this ; perhaps motion detectors only require that contrast exceed some low threshold .
( 8) strength of the aftereffect is affected not by stripe width and speed per se , but by the number of edge crossings .
thus wide stripes require faster movement or longer movement duration to achieve the same aftereffect as narrow stripes . as with the negative afterimage , students can measure the duration of aftereffect under various conditions , such as short or long adaptation periods and varying sizes , speeds , contrasts , or colors of adapting stimuli .
some of them translate one type of motion into another ( e.g. , expansion into rotation ) , while others appear to move when completely stationary .
these illusions are not as easily explained as the aftereffect , but students can still benefit from studying them . questions : ( 1 ) is motion equally strong across the visual field ? ( 2 ) can you start and stop the motion by looking at the image in different ways ? ( 3 ) are all four colors needed ? can you change the strength or direction of motion by altering the color scheme ? ( 4 ) can adaptation to illusory motion cause a motion aftereffect ? interpretations : ( 1 ) most people see little or no motion at the point of fixation , with movement being most apparent in the peripheral visual field .
( 2 ) if one makes an effort to stare fixedly at one point without eye movements , motion is reduced or stopped .
( 3 ) only three colors are needed ( motion survives replacement of red with black in figure 3 ) .
motion is usually in the direction of the darker of the two ovals that surround a dark hourglass shape , but exceptions can be found , including some that appear to move weakly and in an ambiguous direction ( make all shapes black but one white hourglass ) .
( 4 ) after adapting to one large disc , one may get a weak aftereffect .
although these exercises seem to reveal little about the mechanisms behind this illusion , they reflect the ways in which scientists approach the subject .
observations about weakness in the central visual field , the effect of contrast , and eye movements led to the current explanations of this illusion ( conway et al . , 2005 ; murakami et al . , 2006 ) .
there are many illusions of contrast , both in luminance and color . despite straightforward explanations invoking lateral inhibition or other local mechanisms ,
figure 4 shows two cases in which gray blocks of equal density appear darker or lighter because of their surroundings and one case in which identically colored crosses appear quite different . in psycog and many online demonstrations
questions : ( 1 ) can you predict the outcome of a variety of contrast illusions ? how are they usually explained ? ( 2 ) how do assimilation illusions ( e.g. , the munker - white illusion , figure 4 center ) challenge those explanations ? ( 3 ) how would you measure the strength of a contrast illusion or test whether everyone is fooled by the same amount ?
interpretations : ( 1 ) it is not always easy to predict how a patch of color will appear based on its surroundings , since surroundings sometimes enhance contrast ( top and bottom panels of figure 4 ) and sometimes reduce it ( center panel ) . ( 2 ) explanations invoking contrast or edge enhancement make the wrong predictions in assimilation illusions . in the munker - white illusion ( figure 4 center panel ) , gray areas on the right border more white than black and thus should darken , while the reverse applies to gray areas on the left . however , our perception is the opposite .
that does not mean that the usual explanations are wrong , only that they can not be applied to all aspects of a scene .
they may still apply to other aspects ( for example , mach bands appear in the munker - white illusion ) .
( 3 ) to measure a contrast illusion , adjust two areas until they are subjectively equal and then measure their difference .
figure 5 illustrates this for a contrast enhancement illusion and an assimilation illusion . as a class project
, student could measure their own contrast adjustments and do a statistical analysis of the pooled data .
( 4 ) look at figure 1 again ; its negative afterimage is magenta , but the center of the afterimage is green . since the original stimulus had no obvious magenta tint in the center , greenness in the afterimage is not itself an afterimage , but contrast enhancement occurring within the afterimage .
thus contrast enhancement is taking place after color - opponent cells , in v1 or later .
i have omitted some very striking ones such as the scintillating grid ( schrauf et al . , 1995 ) because of their complexity .
they still have use in teaching , both to excite interest and as fodder for mechanistic speculation . for further discussion of contrast illusions , particularly those resistant to easy explanation , see purves and lotto ( 2003 ) .
explanations of size and orientation illusions are still very much in dispute , but they have the advantage of being easy to measure . nearly everyone has seen the mller - lyer illusion ( figure 6 ) , so i use it as an example .
the questions it raises apply equally to the ponzo , poggendorf , vertical - horizontal , bisection , lipps , ebbinghaus - delboef , zollner , and hering illusions and many others .
questions : ( 1 ) how would you measure the strength of a size illusion or test whether everyone is off by the same amount ?
( 2 ) what experimental controls would you need to show that people misperceive size ?
( 3 ) how could you test the hypothesis that misjudgment of length results from use of perspective cues ?
( 4 ) can you train yourself to make accurate size judgments in the mller - lyer illusion ?
if so , do the two lines actually look equal , or are you just compensating to make them equal ? interpretations : ( 1 ) rather than showing two equal lines that appear unequal , have the observer make the lines subjectively equal .
data from a large class ( along with controls ) could be used for practice in statistical analysis .
( 2 ) at a minimum , we should check that people are able to adjust simple lines to equality ( we do so easily ) .
( 3 ) if the mller - lyer illusion is due to perspective cues , then it should occur when the ends are arrowheads but not when they are circles , brackets , or other shapes that make no sense in the context of depth .
( 4 ) most people can set the lines equal with practice but still see them as unequal .
gregory ( 1998 ) and gillam ( 1998 ) argue that the slants and angles in illusions are interpreted as perspective cues .
rock ( 1995 ) proposes that the size and orientation of an object are perceived in contrast with those of its local background .
prinzmetal and beck ( 2001 ) attribute several illusions to mechanisms that correct for head tilt .
purves and lotto ( 2003 ) propose that perception is determined by the statistical relationship between the retinal image and all its possible sources .
it is interesting that , after years of study , there are still no generally accepted explanations for these ubiquitous illusions . although disappointing at some level , this makes such illusions ripe for student projects that test competing hypotheses .
there are so many good ( and bad ) web sites with visual illusions that it is difficult to keep track of them .
these four sites offer explanations along with good graphics :
http://sites.sinauer.com/wolfe3e/home/startf.htmwolfe et al.s sensation and perception companion site has demonstrations and explanations keyed to the text but available to all.http://www.michaelbach.de/ot/index.htmlmichael bach s site lets one manipulate many illusions ; also includes explanations and references.http://www.ritsumei.ac.jp/~akitaoka/index-e.htmlakiyoshi kitaoka s site has many illusions , including his novel illusory motion ones , with links to his research papers on illusions.http://illusioncontest.neuralcorrelate.com/the vision sciences society has an annual contest for new illusions ; the site links to published explanations .
http://sites.sinauer.com/wolfe3e/home/startf.htm wolfe et al.s sensation and perception companion site has demonstrations and explanations keyed to the text but available to all .
michael bach s site lets one manipulate many illusions ; also includes explanations and references .
akiyoshi kitaoka s site has many illusions , including his novel illusory motion ones , with links to his research papers on illusions .
http://illusioncontest.neuralcorrelate.com/ the vision sciences society has an annual contest for new illusions ; the site links to published explanations .
as even these simple examples show , illusions are often complex and contradictory , with results that are hard to explain with basic textbook - level knowledge . while this can be frustrating at times , it is also exciting
. it shows students that science is not simply a recitation of facts , but a process of testing hypotheses about the unknown .
better still , this process is open to students through their own perception of stimuli that they can design and manipulate .
illusions can be used in introductory classes to stimulate interest and illustrate basic concepts ( at the risk of over - simplification ) . beyond that , in - class demonstrations can identify critical aspects of stimuli , show the importance of controls , and possibly analyze class - generated data .
more advanced classes might focus on mechanisms and the complexity of an apparently simple illusion .
most illusions combine several effects at once , and a class could work on identifying all features or simplifying an illusion to isolate one mechanism .
meeting these challenges should make teaching more fun for instructors as well as their students .
Output:
| many phenomena that we take for granted are illusions color and motion on a tv or computer monitor , for example , or the impression of space in a stereo music recording .
even the stable image that we perceive when looking directly at the real world is illusory .
one of the important lessons from sensory neuroscience is that our perception of the world is constructed rather than received .
sensory illusions effectively capture student interest , but how do you then move on to substantive discussion of neuroscience ?
this article illustrates several illusions , attempts to connect them to neuroscience , and shows how students can explore and experiment with them .
even when ( as is often the case ) there is no agreed - upon mechanistic explanation for an illusion , students can form hypotheses and test them by manipulating stimuli and measuring their effects . in effect , students can experiment with illusions using themselves as subjects . |
PubmedSumm118767 | ***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: occupational noise exposure is recognised as a substantial risk factor for hearing loss , and worldwide , it remains the most frequent cause of preventable sensorineural hearing loss .
this has led to an extensive research into the auditive effects of occupational noise , and in consequence , preventive measures have been implemented .
these include engineering solutions minimising noise emission and reflection , and legislations limiting the time of work - related noise exposure and obliging the use of hearing protection devices ( hpd ) .
this means that industrial noise levels and individual occupational noise exposure have potentially changed over the last few decades , at least in the developed countries .
there are , therefore , good reasons to continue assessing the burden of auditive disease from occupational noise at national or sub - national levels to follow up on the possible effect of preventive initiatives .
a recent systematic review on occupational noise exposure and hearing concluded that hearing loss due to workplace noise was a significant problem in the 1960s and 1970s in industrialised countries , but the impact seemed to have decreased since that period .
this was suggested to be due to preventive measures , improved regulation or decreased noise exposure .
the evidence , however , was still limited mainly due to blunt or incomplete exposure data .
results from other recent studies , also seem to differ between industries , and these studies are often based on one specific profession , limiting generalisation of results . on the basis of the cross - sectional data collected in 20012003 , we found a three - fold increased risk of hearing handicap among the workers with first exposure to occupational noise before the 1980s .
however , the workers starting their work in a noisy environment during later years showed no increased risk .
the main objectives of this study were to describe the trends in industrial noise exposure levels and use of hpd over a 10-year period .
furthermore , we aimed to evaluate the association between current , danish industrial noise levels and hearing threshold shift in the same period and analyse whether year of first occupational noise exposure was associated with hearing loss .
this study has taken advantage of an initial survey of 819 workers conducted between 2001 and 2003 in aarhus , denmark , with the purpose of monitoring occupational noise exposure , auditory function and preventive measures ( use of hearing hpd ) among noise - exposed workers .
participants were recruited from randomly selected companies within 12 trades : children day care ( due to reports indicating high noise levels in these units ) , financial services ( expected to have low - level noise exposure ) and the 10 manufacturing trades in denmark with the highest reporting of noise - induced hearing loss according to the danish working environment authority . in 20092010 , the same companies and workers were asked to participate again .
owing to time and economic restraints , 202 participants ( 27% ) were not contacted ( at random ) leaving 554 eligible for follow - up .
a total of 271 workers ( 49% ) responded and agreed to participate again . at follow - up
, 394 workers within the 12 trades were recruited de novo to include new workers first to have been noise - exposed during later years , making a total of 665 participants in the follow - up cohort . for cross - sectional analysis of the baseline population
, we excluded 76 workers with incomplete questionnaire exposure information or no noise dosimetry , 16 workers with incomplete audiometry , 109 white - collar workers ( typically managers and office workers considered to differ considerably from the remaining population with respect to extraneous predictors of hearing loss ) , 65 workers reporting current or prior chronic middle - ear infection or tympanic membrane perforation ( possible conductive hearing loss ) and finally 14 workers with asymmetrical hearing loss ( possible hearing loss from other causes than noise , as defined in section audiometric measures ) , resulting in 539 eligible workers for baseline cross - sectional analysis .
correspondingly , for cross - sectional analyses on the follow - up population , we excluded 38 workers with incomplete questionnaire exposure information or no noise - dosimetry , 98 white - collar workers , 75 workers reporting current or prior chronic middle - ear infection or tympanic membrane perforation and 30 workers with asymmetrical hearing loss , resulting in 424 eligible workers .
for the longitudinal analyses , we focused on the 271 workers participating in both surveys .
we excluded two workers with incomplete questionnaire exposure information , 48 white - collar workers and the workers reporting either chronic middle ear infection ( n = 2 ) , tympanic membrane perforation ( n = 2 ) , scull fracture ( n = 0 ) concussion ( n = 1 ) , meningitis ( n = 0 ) or meniere s disease ( n = 0 ) in the follow - up period , resulting in a final study population of 207 persons .
air - conduction thresholds were determined for each ear at 0.25 , 0.5 , 1 , 2 , 3 , 4 , 6 and 8 khz by pure - tone audiometry at the workplaces , using a voyager 522 audiometer equipped with tdh-39 headphones ( madsen electronics , taastrup , denmark ) .
the audiometer was installed in a mobile examination unit equipped with a soundproof booth ( model ab-4240 , eckel noise control technologies , bagshot , uk ) .
audiometry was performed by trained examiners using a standardised protocol ( according to iso 8253 - 1:2010 ) . to avoid the temporary threshold shifts ( tts ) from possible noise sources , all participants were asked to wear hpd from the beginning of the workday until the audiometry was performed .
the majority of the workers were daytime workers ( around 90% in both surveys ) , and we expected a limited noise exposure prior to starting the work ( mostly night time noise at home ) and thus limited risk of tts .
otoscopy verified that ears were free of wax , and the tympanic membrane was visible .
the audiometer was calibrated every six months according to iso 389 - 1:1998 . on the basis of pure - tone air - conduction thresholds , we calculated an average binaural hearing threshold level for the critically noise - sensitive frequencies at baseline and follow - up ( 36 khz - htl - bl or 36 khz - htl - fu ) . correspondingly , a baseline hearing loss variable and a follow - up hearing loss variable ( 36 khz - hl - bl and 36 khz - hl - fu ) were defined , if 36 khz - htl - bl or 36 khz - htl - fu was above 20 db . threshold shift from baseline to follow - up ( 36 khz - htl ) was calculated by subtracting the baseline hearing thresholds ( 36 khz - htl - bl ) from the follow - up hearing thresholds ( 36 khz - htl - fu ) .
we regarded an inter - aural difference of 20 dbhl or more in two consecutive frequencies from 3 to 6 khz as an asymmetrical hearing loss .
for the purpose of this study , information on age , sex , professional history ( current and prior employment , duration , industry , occupation ( blue vs. white collar ) ) , use of hpd and the workers judgement ( whether noise levels in prior jobs were higher , comparable or lower ) was retrieved . at baseline and follow - up , individual dosimeters ( bruel & kjr , model 4443 , naerum , denmark ) measuring a - weighted equivalent sound levels ( l
aeq ) in 5-second intervals during the full work shift were handed out to the participants .
microphones were fitted at the right side collar if they were right - handers and vice versa if left - handers .
individual a - weighted equivalent noise levels were computed for the full work shift ( l
aeq , work ) .
subsequently , workplace and trade - specific mean noise levels were calculated based on the individual dosimetries . as noise levels
were expected to vary more from day to day for the individual worker than between the different workers , we estimated the most efficient grouping strategy based on the highest contrast in mean exposure level between the groups .
this was accomplished by modelling the noise exposure with two mixed effect models including either worker and the industry or worker and company as random effects .
the highest contrast was found using company - means , and thus worker s noise exposure was classified by the mean l
aeq - value calculated for their workplace and not by her / his individual measurement .
the estimation of cumulative occupational noise exposure in the follow - up period was based on ( 1 ) the questionnaire information on current and previous employment details including company , period , and the workers subjective judgement of whether any previous jobs involved comparable or higher noise exposure levels than their current job , and ( 2 ) workplace average l
aeq levels at baseline and follow - up .
each individual employment year was given a noise exposure level based on the following criteria : ( 1 ) if the year was within an employment period in a company included in the study , the average workplace level was applied ( 2 ) for employment periods in companies not included in the study , the noise exposure was classified from the participants judgement of the noise levels , that is , ( a ) if the worker reported that the noise levels in a prior job were comparable to or higher than the level of the current job ( were noise measurements was performed ) , these years were given the same level as in the current workplace or ( b ) if the noise level was judged to be substantially lower than that of the exposure at the current company , then this employment period would be classified as non - exposed . finally , we calculated cumulative occupational noise exposure levels for each participant in the follow - up period as the product of estimated noise exposure level ( l
aeq in db(a ) ) and the duration of employment ( t ) using the formula : 10 log [ (10 t ] , resulting in
the same model was used to estimate the first year of occupational noise exposure > 80 db(a ) and the number of years exposed to the mean occupational noise levels > 80 db(a ) and > 85 db(a ) , respectively .
we tabulated sex , age and industry across decade of first year of an occupational noise exposure above 80 db(a ) for the baseline and follow - up populations [ table 1 ] .
for the workers who participated in both surveys , we tabulated sex , age , 36 khz - hl - bl , occupational noise exposure before baseline and hpd use across three categories of cumulative occupational noise in the follow - up period [ table 2 ] .
characteristics of 539 workers from the baseline population and 424 workers from the follow - up population by year of first occupational noise exposure > 80 db(a ) , aarhus , denmark characteristics of the 207 workers participating at both baseline and follow - up by tertiles of cumulative occupational noise exposure ( db(a)-years ) in the follow - up period , aarhus , denmark , 2009 * defined as an average binaural hearing threshold > 20 db in the noise sensitive frequencies ( 3 , 4 and 6 khz ) .
logistic regression was used to estimate the association between first year of occupational noise exposure > 80 db(a ) and hearing loss in the critically noise - sensitive frequencies for the baseline and the follow - up populations , adjusting for age and sex [ table 3 ] .
age and sex adjusted odds ratios ( or ) of hearing handicap in the critically noise sensitive frequencies according to year of first noise exposure among the baseline and follow - up populations * defined as an average binaural hearing threshold > 20 db in the noise sensitive frequencies ( 3 , 4 and 6 khz ) among the workers participating in both the surveys , the crude and the adjusted associations between noise exposure variables and hearing threshold shift in the follow - up period were examined , using the linear regression with the lowest exposure group as a reference [ table 4 ] .
stratified analyses were performed to evaluate the possible effect modification from a prior occupational noise exposure and baseline hearing loss on the association between cumulative noise exposure and hearing threshold shift in the follow - up period .
crude and adjusted associations between noise exposure variables and bilateral hearing threshold shift in the critically noise sensitive frequencies ( 36 khz ) among 207 workers followed from baseline to follow - up adjusted for sex and age . adjusted for sex , age , baseline hearing threshold and prior noise exposure > 10 years hpd use at baseline and follow - up was cross - tabulated with age and gender to identify possible changes in use over the follow - up period [ table 5 ] . to look for changes in noise emission from the industries included in this study , we calculated mean industry noise levels based on all individual blue - collar noise recordings at baseline and follow - up [ table 6 ] . hpd use at baseline and follow - up according to occupational noise level ,
sex and age group mean noise levels per industry at baseline and follow - up , aarhus , demnark in a sub - analysis , we subtracted 10 db(a ) from company noise levels if workers reported to use hpd , and we repeated the analyses between the cumulative noise exposure variable and hearing threshold shift in the follow - up period as described above . the stata statistical package ( version 13 , statacorp , college station , tx , usa ) was used for all analyses .
this study has taken advantage of an initial survey of 819 workers conducted between 2001 and 2003 in aarhus , denmark , with the purpose of monitoring occupational noise exposure , auditory function and preventive measures ( use of hearing hpd ) among noise - exposed workers .
participants were recruited from randomly selected companies within 12 trades : children day care ( due to reports indicating high noise levels in these units ) , financial services ( expected to have low - level noise exposure ) and the 10 manufacturing trades in denmark with the highest reporting of noise - induced hearing loss according to the danish working environment authority . in 20092010 , the same companies and workers were asked to participate again .
owing to time and economic restraints , 202 participants ( 27% ) were not contacted ( at random ) leaving 554 eligible for follow - up .
a total of 271 workers ( 49% ) responded and agreed to participate again . at follow - up
, 394 workers within the 12 trades were recruited de novo to include new workers first to have been noise - exposed during later years , making a total of 665 participants in the follow - up cohort . for cross - sectional analysis of the baseline population
, we excluded 76 workers with incomplete questionnaire exposure information or no noise dosimetry , 16 workers with incomplete audiometry , 109 white - collar workers ( typically managers and office workers considered to differ considerably from the remaining population with respect to extraneous predictors of hearing loss ) , 65 workers reporting current or prior chronic middle - ear infection or tympanic membrane perforation ( possible conductive hearing loss ) and finally 14 workers with asymmetrical hearing loss ( possible hearing loss from other causes than noise , as defined in section audiometric measures ) , resulting in 539 eligible workers for baseline cross - sectional analysis .
correspondingly , for cross - sectional analyses on the follow - up population , we excluded 38 workers with incomplete questionnaire exposure information or no noise - dosimetry , 98 white - collar workers , 75 workers reporting current or prior chronic middle - ear infection or tympanic membrane perforation and 30 workers with asymmetrical hearing loss , resulting in 424 eligible workers .
for the longitudinal analyses , we focused on the 271 workers participating in both surveys .
we excluded two workers with incomplete questionnaire exposure information , 48 white - collar workers and the workers reporting either chronic middle ear infection ( n = 2 ) , tympanic membrane perforation ( n = 2 ) , scull fracture ( n = 0 ) concussion ( n = 1 ) , meningitis ( n = 0 ) or meniere s disease ( n = 0 ) in the follow - up period , resulting in a final study population of 207 persons .
air - conduction thresholds were determined for each ear at 0.25 , 0.5 , 1 , 2 , 3 , 4 , 6 and 8 khz by pure - tone audiometry at the workplaces , using a voyager 522 audiometer equipped with tdh-39 headphones ( madsen electronics , taastrup , denmark ) .
the audiometer was installed in a mobile examination unit equipped with a soundproof booth ( model ab-4240 , eckel noise control technologies , bagshot , uk ) .
audiometry was performed by trained examiners using a standardised protocol ( according to iso 8253 - 1:2010 ) . to avoid the temporary threshold shifts ( tts ) from possible noise sources , all participants were asked to wear hpd from the beginning of the workday until the audiometry was performed .
the majority of the workers were daytime workers ( around 90% in both surveys ) , and we expected a limited noise exposure prior to starting the work ( mostly night time noise at home ) and thus limited risk of tts .
otoscopy verified that ears were free of wax , and the tympanic membrane was visible .
the audiometer was calibrated every six months according to iso 389 - 1:1998 . on the basis of pure - tone air - conduction thresholds , we calculated an average binaural hearing threshold level for the critically noise - sensitive frequencies at baseline and follow - up ( 36 khz - htl - bl or 36 khz - htl - fu ) . correspondingly , a baseline hearing loss variable and a follow - up hearing loss variable ( 36 khz - hl - bl and 36 khz - hl - fu ) were defined , if 36 khz - htl - bl or 36 khz - htl - fu was above 20 db .
threshold shift from baseline to follow - up ( 36 khz - htl ) was calculated by subtracting the baseline hearing thresholds ( 36 khz - htl - bl ) from the follow - up hearing thresholds ( 36 khz - htl - fu ) .
we regarded an inter - aural difference of 20 dbhl or more in two consecutive frequencies from 3 to 6 khz as an asymmetrical hearing loss .
all participants filled in a questionnaire providing information on medical and professional history . for the purpose of this study , information on age , sex , professional history ( current and prior employment , duration , industry , occupation ( blue vs. white collar ) ) , use of hpd and the workers judgement ( whether noise levels in prior jobs were higher , comparable or lower ) was retrieved .
at baseline and follow - up , individual dosimeters ( bruel & kjr , model 4443 , naerum , denmark ) measuring a - weighted equivalent sound levels ( l
aeq ) in 5-second intervals during the full work shift were handed out to the participants .
microphones were fitted at the right side collar if they were right - handers and vice versa if left - handers .
individual a - weighted equivalent noise levels were computed for the full work shift ( l
aeq , work ) .
subsequently , workplace and trade - specific mean noise levels were calculated based on the individual dosimetries . as noise levels
were expected to vary more from day to day for the individual worker than between the different workers , we estimated the most efficient grouping strategy based on the highest contrast in mean exposure level between the groups .
this was accomplished by modelling the noise exposure with two mixed effect models including either worker and the industry or worker and company as random effects .
the highest contrast was found using company - means , and thus worker s noise exposure was classified by the mean l
aeq - value calculated for their workplace and not by her / his individual measurement .
the estimation of cumulative occupational noise exposure in the follow - up period was based on ( 1 ) the questionnaire information on current and previous employment details including company , period , and the workers subjective judgement of whether any previous jobs involved comparable or higher noise exposure levels than their current job , and ( 2 ) workplace average l
aeq levels at baseline and follow - up . each individual employment year
was given a noise exposure level based on the following criteria : ( 1 ) if the year was within an employment period in a company included in the study , the average workplace level was applied ( 2 ) for employment periods in companies not included in the study , the noise exposure was classified from the participants judgement of the noise levels , that is , ( a ) if the worker reported that the noise levels in a prior job were comparable to or higher than the level of the current job ( were noise measurements was performed ) , these years were given the same level as in the current workplace or ( b ) if the noise level was judged to be substantially lower than that of the exposure at the current company , then this employment period would be classified as non - exposed . finally , we calculated cumulative occupational noise exposure levels for each participant in the follow - up period as the product of estimated noise exposure level ( l
aeq in db(a ) ) and the duration of employment ( t ) using the formula : 10 log [ (10 t ] , resulting in
the same model was used to estimate the first year of occupational noise exposure > 80 db(a ) and the number of years exposed to the mean occupational noise levels > 80 db(a ) and > 85 db(a ) , respectively .
we tabulated sex , age and industry across decade of first year of an occupational noise exposure above 80 db(a ) for the baseline and follow - up populations [ table 1 ] .
for the workers who participated in both surveys , we tabulated sex , age , 36 khz - hl - bl , occupational noise exposure before baseline and hpd use across three categories of cumulative occupational noise in the follow - up period [ table 2 ] .
characteristics of 539 workers from the baseline population and 424 workers from the follow - up population by year of first occupational noise exposure > 80 db(a ) , aarhus , denmark characteristics of the 207 workers participating at both baseline and follow - up by tertiles of cumulative occupational noise exposure ( db(a)-years ) in the follow - up period , aarhus , denmark , 2009 * defined as an average binaural hearing threshold > 20 db in the noise sensitive frequencies ( 3 , 4 and 6 khz ) . logistic regression was used to estimate the association between first year of occupational noise exposure > 80 db(a ) and hearing loss in the critically noise - sensitive frequencies for the baseline and the follow - up populations , adjusting for age and sex [ table 3 ] .
age and sex adjusted odds ratios ( or ) of hearing handicap in the critically noise sensitive frequencies according to year of first noise exposure among the baseline and follow - up populations * defined as an average binaural hearing threshold > 20 db in the noise sensitive frequencies ( 3 , 4 and 6 khz ) among the workers participating in both the surveys , the crude and the adjusted associations between noise exposure variables and hearing threshold shift in the follow - up period were examined , using the linear regression with the lowest exposure group as a reference [ table 4 ] .
stratified analyses were performed to evaluate the possible effect modification from a prior occupational noise exposure and baseline hearing loss on the association between cumulative noise exposure and hearing threshold shift in the follow - up period .
crude and adjusted associations between noise exposure variables and bilateral hearing threshold shift in the critically noise sensitive frequencies ( 36 khz ) among 207 workers followed from baseline to follow - up adjusted for sex and age . adjusted for sex , age , baseline hearing threshold and prior noise exposure > 10 years hpd
use at baseline and follow - up was cross - tabulated with age and gender to identify possible changes in use over the follow - up period [ table 5 ] . to look for changes in noise emission from the industries included in this study
, we calculated mean industry noise levels based on all individual blue - collar noise recordings at baseline and follow - up [ table 6 ] .
sex and age group mean noise levels per industry at baseline and follow - up , aarhus , demnark in a sub - analysis , we subtracted 10 db(a ) from company noise levels if workers reported to use hpd , and we repeated the analyses between the cumulative noise exposure variable and hearing threshold shift in the follow - up period as described above . the stata statistical package ( version 13 , statacorp , college station , tx , usa ) was used for all analyses .
as shown in table 1 , the women - to - man ratio was lower with earlier first noise exposure in baseline and follow - up populations .
in addition , mean age was higher with earlier first noise exposure in both the populations . among the 207 workers participating in both surveys
, we observed a tendency towards a higher prevalence of males among the workers exposed to higher cumulative noise levels and more frequent use of hpd , but no difference in the prevalence between baseline and follow - up [ table 2 ] .
conversely , the mean age seemed to be lower with the higher cumulative noise exposure [ table 2 ] .
table 3 shows adjusted odds ratios ( ors ) of hearing loss in the critically noise - sensitive frequencies ( as defined in section audiometric measures ) by year of first occupational noise exposure for the baseline and follow - up populations . for the baseline population , we observed no increased risk of hearing loss among those with first exposure after the 1980s compared to that of the reference group ( adjusted or : 1.02 , 95% confidence interval ( ci ) 0.59 ; 1.77 ) .
for the baseline workers with the first exposure before the 1980s , we found a statistically significantly increased risk of hearing loss ( adjusted or : 1.90 , 95% ci 1.11 ; 3.22 ) compared to that of the reference group .
for each extra year since the first exposure , we found an or of 1.02 for the hearing loss ( 95% ci 1.00 ; 1.04 ) among the baseline workers .
for the follow - up population , we also observed a tendency towards an increased risk of hearing loss with a longer time since the first exposure , but results were statistically insignificant .
thus , the adjusted or for hearing loss for the group with the earliest exposure ( before the 1980s ) was 1.48 ( 95% ci 0.58 ; 3.77 ) . in the longitudinal analyses of the 207 workers , participating in both the surveys , we initially performed analyses on the association between the cumulative noise exposure and the hearing threshold shift in the follow - up period stratified by baseline hearing status and prior noise exposure , to account for a possible effect modification from these factors [ table 4 ] .
results showed only marginal differences between the strata , and wald tests indicated no effect modification by these variables .
therefore , we proceeded with the main longitudinal analyses without stratification for baseline hearing status and prior noise exposure .
adjusted results showed a weak , statistically insignificant , inverse association between higher cumulative noise exposure and the hearing threshold shift during the 10-year period .
thus , an average hearing threshold shift in the period was 0.09 db for each extra noise - year ( 95% ci 0.35 ; 0.17 ) ( adjusted for age and sex ) . a vague inverse association was also found between higher number of years exposed > 80 db ( 0.06 db threshold shift per extra year exposed > 80 db(a ) ( 95% ci 0.57 ; 0.29 ) ( adjusted for age and sex ) , but this association turned weakly positive when analysing number of years exposed > 85 instead ( 0.08 db threshold shift per extra year exposed > 85 db(a ) ) ( adjusted for age and sex ) .
no association was found between occupational noise level measured at baseline and hearing threshold shifts .
accounting for the use of hpd by adjusting analyses for hpd use or subtracting 10 db(a ) from company noise levels for the sub - group reporting daily use of hpd did not noticeably change the association between the cumulative occupational noise and hearing threshold shift in the follow - up period ( association when adjusting for hpd : 0.11 db per noise - year ( 95% ci 0.38 ; 0.16 ) , and association when subtracting 10 db if hpd was used : 0.09 ( 95% ci 0.26 ; 0.10 ) ) . according to table 5 , 70% of the baseline population exposed to noise levels > 85 db(a ) used hpd , raising to 76% among the follow - up population .
around 75% of men and 50% of women used hpd when exposed > 85 db(a ) at both surveys .
no distinctive differences in hpd use between the age groups were observed at either the baseline or follow - up populations .
table 6 shows a general decline in noise levels from baseline to follow - up across the noisy industries included in this study . only
manufacture of machinery showed an increasing noise level from 81.3 db(a ) at baseline to 81.8 db(a ) at follow - up .
the most prominent fall in noise level over the follow - up period was seen in
average decline for all the included industries from baseline to follow - up was 1.1 db(a ) .
main results from this study indicate that worker s cumulative occupational noise exposure during the follow - up period from 2000 to 2010 was not associated with statistically significant changes in hearing in the critically noise - sensitive frequencies . by categorising the baseline and the follow - up workers by their year of first noise exposure
> 80 db(a ) , we found the highest risk of hearing loss among workers with first exposure before the 1980s in the baseline as well as the follow - up populations .
the prevalence of hpd use among workers exposed to average occupational noise levels > 85 db(a ) increased from 70.1% in 20012003 to 76.1% in 20092010 , whereas mean noise levels in the included industries decreased with 1.1 db(a ) .
an average decline in noise level of 1.1 db(a ) over 10 years may appear small , but remembering that 1 db represents a power ratio of approximately 1.26 ( the decibel is a logarithmic unit ) , the effect on hearing preservation may be significant .
in addition , some of the largest declines in mean noise levels are found among the industries with the highest baseline levels , meaning that no mean industry levels exceeded 85 db(a ) in 20092010 .
however , mean company noise levels used to classify worker s noise exposure still exceed 85 db(a ) for a substantial part of workers , and in this case , around three - quarters of workers reported to use hpd .
accordingly , the finding of no association between recent occupational noise levels and hearing threshold shift among our participants was not unexpected . in a longitudinal cohort study from 2006 ,
an inverse association between 10-year binaural hearing loss rates in the noise - sensitive frequencies ( 3 , 4 and 6 khz ) and higher occupational noise exposure was found among 6217 noise - exposed employees . the authors found
no indication of a healthy worker bias in their analyses and , therefore , speculated if the result could be related to differential use of hpd as they found the majority of large threshold shifts among workers exposed to average noise levels < 85 db , where hpds may not be used as consistently .
we asked workers whether they used hpd in their current job and found that among workers exposed to average noise levels < 85 db(a ) , the use of hpd was in fact substantially lower than that at higher levels [ table 5 ] .
misclassification of actual noise at the ear from differential use of hpd could , therefore , also have introduced a similar bias in our study explaining the null findings .
another 10-year longitudinal study recently conducted on construction workers in the usa demonstrated that noise levels in this particular industry still constitute a risk for hearing loss in the noise - sensitive frequencies ( 3 , 4 and 6 khz ) , even though the average estimated noise exposure l(eq ) for the workers was only 2 db(a ) above 85 db(a ) .
the study population included only newly hired construction apprentices ( mean age 27.6 years ) assumed to have a limited prior noise exposure and good hearing at inception .
thus , only 50% of the construction workers reported to use hpd , and when observed , the fraction of exposure time , in which hpds were used , was only 1724% . including newly hired apprentices
is an advantage to the study , because an effect modification otherwise may occur from prior noise exposure and poor baseline hearing .
we also included workers with prior noise exposure and workers from a broader age spectrum ( mean age at baseline : 39.9 years ) and , therefore , also performed stratified analyses .
a review from 2015 on occupational noise exposure and hearing concluded that the industrial noise levels in general had been reduced over the last few decades , and that this led to an improved hearing in noise - exposed groups in recent years . only among construction workers
our population was too small to allow for trade - specific sub - analyses , but in general , the conclusions of the review were in line with our findings and , interestingly , we observed the largest fall in noise exposure level from baseline to follow - up among construction workers ( 4.4 db(a ) ) . among the strengths of our study
much of prior literature in this field is derived from cross - sectional studies lacking temporal specificity .
furthermore , our exposure quantification derived from individual dosimetries gives objective measures instead of subjective questionnaire information as often used to classify noise level .
we did not have the capacity to measure bone conduction thresholds , which would have been a better measure of sensorineural hearing threshold .
instead , we excluded participants with possible conductive hearing loss and asymmetric hearing loss from analyses to avoid misclassification .
as the white - collar workers were considered to differ considerably from the remaining population with respect to covariates ( e.g. leisure time noise ) that we were not able to adjust for , we decided to restrict the population to occupationally noise - exposed workers .
exposure contrast in this group was considered sufficient , with individual exposure levels ranging from 67.5 db(a ) to 106.0 db(a ) . a lower loss to follow - up than 51% in our study
would have been desirable , but in our selected industries with expected low job tenancy , we find a follow - up of 49% reasonable . among the workers participating in both the surveys
, we identified 12 workers ( 4.4% ) , who moved from high to low exposure jobs . if this shift was made because of a higher susceptibility to noise exposure among the 12 workers , it could potentially introduce a
healthy worker bias by attenuating the exposure response relationship . by regression analysis , we , therefore , analysed if there was an association between a change from high - to - low exposure job during the 10-year period and baseline hearing levels .
we found no significant association , indicating that this was not an issue of concern .
another possibility of bias in our study is the misclassification of noise exposure due to hpd use .
information on hpd use was retrieved from the questionnaire and was not controlled by observation of actual behaviour .
as mentioned above , prior studies have revealed a large discrepancy between self - reported use and actual behaviour which could also be the case in our study .
to analyse whether ( self - reported ) hpd use had any impact on our results , we performed the sub - analyses subtracting 10 db from the company noise exposure levels for workers reporting the hpd use and also tried to adjust the regression analyses for the use of hpd .
however , as mentioned above , a differential misclassification of actual noise at the ear by a more consistent use of hpd at noise levels above 85 db(a ) is still a possibility and could have biased our results by attenuating the exposure response relationship . to avoid tts , we instructed participants to wear hpd from the beginning of the working day until an audiometry was performed .
participants hearing could , however , still be affected by , for example , prior traffic or leisure time noise exposure .
as most participants ( around 90% in both surveys ) worked only daytime ( approximately 7 a.m. to 4 p.m. ) , we expected their prior noise exposure ( mostly night time noise at home ) to be low and should , therefore , not cause significant tts . using average company noise levels to classify worker
we expected the sound levels to vary more from one day to another day for the individual workers than that between the different workers and chose it over industry means , because analyses of variance showed most exposure contrast using company levels .
misclassification is , however , still a possibility but should be non - differential across noise exposure levels and would , therefore , bias results towards the null .
this study demonstrates a fall in recent industrial noise levels , increasing use of hpd and no association between the current occupational noise levels and hearing threshold shift .
we interpret these findings as an indication of a successful implementation of preventive measures enforced in denmark during the last few decades to prevent noise - induced hearing loss .
Output:
| aims : to survey current , danish industrial noise levels and the use of hearing protection devices ( hpd ) over a 10-year period and to characterise the association between occupational noise and hearing threshold shift in the same period .
furthermore , the risk of hearing loss among the baseline and the follow - up populations according to first year of occupational noise exposure is evaluated.materials and methods : in 20012003 , we conducted a baseline survey of noise- and hearing - related disorders in 11 industries with suspected high noise levels . in 20092010
, we were able to follow up on 271 out of the 554 baseline workers ( 49% ) .
mean noise levels per industry and self - reported hpd use are described at baseline and follow - up .
the association between cumulative occupational noise exposure and hearing threshold shift over the 10-year period was assessed using linear regression , and the risk of hearing loss according to year of first occupational noise exposure was evaluated with logistic regression.results:over the 10-year period , mean noise levels declined from 83.9 db(a ) to 82.8 db(a ) , and for workers exposed > 85 db(a ) , the use of hpd increased from 70.1 to 76.1% .
we found a weak , statistically insignificant , inverse association between higher ambient cumulative noise exposure and poorer hearing ( 0.10 db hearing threshold shift per db - year ( 95% confidence interval ( ci ) : 0.36 ; 0.16 ) ) .
the risk of hearing loss seemed to increase with earlier first year of noise exposure , but odds ratios were only statistically significant among baseline participants with first exposure before the 1980s ( odds ratio : 1.90 , 95% ci : 1.11 ; 3.22).conclusions : we observed declining industrial noise levels , increased use of hpd and no significant impact on hearing thresholds from current ambient industrial noise levels , which indicated a successful implementation of danish hearing conservation programs . |
PubmedSumm118768 | ***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: rejection in renal allograft is mediated by t cells ( t - cell - mediated rejection ) or by donor - specific antibodies ( dsas ) ( antibody mediated rejection , abmr ) .
after its introduction in banff 1997 , the criteria for abmr have been revised and refined on the basis of morphologic tissue injury , evidence of current / recent antibody - vascular endothelial interaction , and serologic evidence of dsas , human leukocyte antigen 's ( hla 's ) or other antigens . though not included in banff schema , plasma cell - rich acute rejection ( pcar )
is recognized as a distinct entity due to its peculiar morphology and poor prognostic behavior .
several original studies and case reports have elicited the clinicomorphologic features of pcar along with therapeutic nuances in elaborate details .
it is known that pcar is a combined cell - mediated and abmr . in the last 20 months , we have observed seven allograft biopsies showing morphologic features of pcar with positivity for c4d and dsa satisfying the banff criteria for an additional component of abmr .
our centre is a tertiary care university hospital with active nephrology services routinely performing renal transplants ( cadaver and live related ) .
the standard triple immunosupression is followed at our centre that includes steroid based therapy , calcineurine inhibitors ( cyclosporine or tacrolimus ) along with azathioprine or mycophenolate mofetil .
the clinical details were noted with respect to age , type of graft , transplant duration , hla matching , baseline serum creatinine , and creatinine at the time of biopsy , therapy given after diagnosis of acute rejection , and subsequent follow - up data .
the biopsies were classified as per the banff 2007 schema by reading the light microscopy with the help of hematoxylin and eosin , periodic acid schiff and silver methanamine stains .
immunohistochemistry ( ihc ) with c4d ( biogenex , india ) is performed on all allograft biopsies as a protocol by polymer horse - radish peroxidize technique .
positivity for c4d is assessed in the peritubular capillaries and scored according to banff 2007 criteria .
the biopsies of pcar with abmr were subjected to additional ihc with cd20 , cd3 , cd 138 and kappa and lambda light chains ( to detect monoclonality ) , and sv 40 large t antigen ( cell marque , usa ) .
scoring for active lesions including interstitial inflammation , tubulitis , glomerulitis , peritubular capillaritis , and arteritis was done as per banff 2007 schema .
total 210 allograft biopsies were performed in the study period of which seven biopsies ( 3.3% ) were diagnosed as pcar with abmr .
total 45 ( 21.4% ) biopsies showed features of acute rejection ; 19 ( 8.0% ) being cell - mediated rejections acute cellular rejection ( acr ) and 26 ( 11.9% ) of acute abmr .
clinical and follow - up parameters comparison of all types of acute rejections all patients of pcar with abmr had received live donor allo grafts and were on standard triple immunosuppression regimen .
all these were late ( more than 6 months ) abmrs with median posttransplant duration of 17 months .
the cytomegalovirus and bk virus ( bkv ) polymerase chain reaction ( pcr ) were negative in all but one patient .
plasma cells were more than 10% in all the biopsies and were seen in the cortical portion [ figure 1 ] separating the tubules .
these were morphologically mature and were found to be polyclonal on kappa and lambda ihc .
the allograft biopsies showing dense infiltrate of plasma cells all the biopsies showed morphologic features of acr in the form of interstitial inflammation and tubulitis as well as abmr such as peritubular capillaritis , glomerulitis , and intimal arteritis [ figures 2 and 3 ] .
all the biopsies showed c4d positivity in peritubular capillaries ( c4d3 ) [ figure 4 ] .
the allograft biopsies with interstitial edema , peritubular capillary dilaltation , and capillaritis ( a and b ) the biopsies showing tubulitis , ( c ) glomerulitis and ( d ) intimal arteritis scoring of the activity and chronicity parameters ( a and b ) immunohistochemical positivity for c4d along the peritubular capillaries ( c ) positivity of plasma cells for cd 138 none of the biopsies showed cd20 lymphoid aggregates .
four of the patients had follow - up biopsies and the scoring on these is given in table 4 .
the morphologic features of rejection persisted in the follow - up biopsies albeit of lesser degree .
follow - up biopsy scoring all the patients were treated with standard therapeutic measures of acr and abmr including methyprednisolone ( 1 g / day three doses ) , plasma exchange , rituximab and intravenous immunoglobulins ( ivig ) and bortezomib .
however , the serum creatinine showed persistent elevation in the due course in four with graft loss in two patients .
the outcome in terms of graft dysfunction and loss was particularly found to be worse in the patients with pcar with abmr in comparison to other acute rejections .
plasma cells were more than 10% in all the biopsies and were seen in the cortical portion [ figure 1 ] separating the tubules .
these were morphologically mature and were found to be polyclonal on kappa and lambda ihc .
the allograft biopsies showing dense infiltrate of plasma cells all the biopsies showed morphologic features of acr in the form of interstitial inflammation and tubulitis as well as abmr such as peritubular capillaritis , glomerulitis , and intimal arteritis [ figures 2 and 3 ] .
all the biopsies showed c4d positivity in peritubular capillaries ( c4d3 ) [ figure 4 ] .
the allograft biopsies with interstitial edema , peritubular capillary dilaltation , and capillaritis ( a and b ) the biopsies showing tubulitis , ( c ) glomerulitis and ( d ) intimal arteritis scoring of the activity and chronicity parameters ( a and b ) immunohistochemical positivity for c4d along the peritubular capillaries ( c ) positivity of plasma cells for cd 138 none of the biopsies showed cd20 lymphoid aggregates .
four of the patients had follow - up biopsies and the scoring on these is given in table 4 .
the morphologic features of rejection persisted in the follow - up biopsies albeit of lesser degree .
all the patients were treated with standard therapeutic measures of acr and abmr including methyprednisolone ( 1 g / day three doses ) , plasma exchange , rituximab and intravenous immunoglobulins ( ivig ) and bortezomib .
however , the serum creatinine showed persistent elevation in the due course in four with graft loss in two patients .
the outcome in terms of graft dysfunction and loss was particularly found to be worse in the patients with pcar with abmr in comparison to other acute rejections .
the presence of plasma cells is associated with viral infections , drug toxicities , posttransplant lymphoproliferative disorder ( ptld ) and acute rejection .
the earliest correlation of plasma cells with graft loss was reported by ndasdy et al . and david - neto et al .
this was followed by the reports of actual pcar was by charney et al . in 1999 .
they described 27 patients of pcar occurring in late posttransplant duration and having poor graft survival .
the series by desvaux et al . and gupta et al . further contributed to the understanding of pcar .
these being relatively late onset of rejection , slight female dominance , polyclonal plasma cell infiltrate , unresponsiveness to treatment and poor prognosis .
charney et al . and gupta et al . have clearly mentioned absence of tissue injury related to abmr in their biopsies and also negativity for c4d .
however in their study demonstrated circulating anti donor antibodies ( n = 12 ) and c4d positivity ( n = 3 ) on the allograft biopsies .
charney et al . also discuss a th 2 cytokine pathway in pcar indicating a humoral response . on similar lines , xu et al .
in an analysis of 40 explanted grafts , found that 57.5% of the grafts having cd138 + plasma cells and 32.5% being positive for both ; cd138 + plasma cells and diffuse c4d deposits .
they thought that plasma cell infiltrate participate in humoral rejection through local secretion of antibodies .
the evidence of abmr was proved without doubt in our biopsies on the basis of light microscopic features as well as positivity for c4d and dsa .
peculiarly all our patients of pcar were male unlike that reported by charney et al . and gupta et al . to have slight female predominance
have most recently described a patient of pcar with abmr occurring 1-year posttransplant who responded to antirejection medication .
the biopsy features described by them are most similar to that observed in our biopsies .
late abmr is being thought as a distinct form of rejection away from chronic abmr .
chronic abmr is characterized by transplant glomerulopathy , peritubular capillary basement membrane multilayering , interstitial fibrosis / tubular atrophy , fibrous intimal thickening with c4d deposition , and positive dsa .
the term chronic is not related to posttransplant duration and thus late amr can have a phenotype of acute or chronic amr .
late amrs are associated with reduction in immunosuppression / noncompliance , unresponsiveness to treatment and graft loss .
though not reported earlier with pcar , three of our patients were found to be noncompliant to the immunosuppression therapy .
the diagnosis of abmr requires the presence of morphologic features , c4d positivity and also positive dsa .
however , it is known that there is no absolute correlation between dsa and amr or c4d positivity .
in a recent publication by larpparisuth et al . , it was shown that dsa was detected in 25 of the 34 patients with late acute abmr .
the presence of plasma cells in allografts has also been studied with respect to chronic graft dysfunction .
have reported the presence of plasma cells , diffuse c4d staining of ptc and dsa on serial allograft biopsies of recipients with chronic dysfunction as compared to a control group with normal renal function .
distinguishing bk nephropathy from acute rejection is of utmost importance due to diverse line of management .
pcar biopsies can show tubular epithelial atypia that can be mistaken for viral cytopathic effects .
in addition , bk nephropathy can show overlapping features of rejection like tubulitis and peritubular capillaritis .
the absence of staining with sv 40 antigen and negative bkv pcr rules out the presence of bkv nephropathy in our biopsies .
polymorphic ptlds can show plasma cell infiltrate with expression of epstein - barr virus ( ebv ) rna .
plasma cells in our biopsies were not atypical , but the presence of ebv rna could not be established in our biopsies .
the treatment options for abmr include steroids , plasmapheresis , rituximab , bortezomib and ivig .
pcars have shown a distinct treatment failure to all these lines of treatment with a poor prognosis in most of the published literature .
the other cases of nonplasma cell acr and abmr showed better therapeutic response and good graft outcome with similar lines of treatment .
the study has limitations since protocol biopsies are not followed at our center . in most of these patients , earlier allograft biopsies were not done which could have picked up possible subclinical rejections or early appearance of plasma cell infiltrates and other morphologic features .
we report seven patients of pcar with abmr diagnosed in late posttransplant period with resistance to the standard antirejection therapy and persistent graft dysfunction with graft loss in two patients .
Output:
| renal allograft rejection is mediated by t - cells ( t - cell mediated rejection ) or by donor - specific antibodies ( dsas ) ( antibody mediated rejection , abmr ) .
plasma cell - rich acute rejection ( pcar ) is a unique entity due to its peculiar morphology and poor prognostic behavior .
all allograft biopsies done at our center from january 2013 to october 2014 were reviewed , and seven were identified with a diagnosis of pcar with antibody mediated rejection ( abmr ) .
the allograft biopsies were classified as per the banff 2007 schema .
immunohistochemistry with c4d , sv 40 , cd3 , cd20 , cd138 , kappa and lambda light chain was performed .
total 210 allograft biopsies were performed in the study period of which seven biopsies ( 3.3% ) were diagnosed as pcar with abmr . all these were late abmrs ( more than 6 months ) with median posttransplant duration of 17 months .
the allograft biopsy showed features of pcar along with glomerulitis , peritubular capillaritis , and positive c4d .
dsa was positive in six patients .
all the patients were treated with standard therapeutic measures of acute cellular rejection ( acr ) and abmr including steroids , plasma exchange , rituximab and intravenous immunoglobulins .
all the patients had persistent graft dysfunction or graft loss on follow - up . |
PubmedSumm118769 | ***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: visual attention is the selection of visual information for purposes such as in - depth processing , perception , or action control . because we have to select information at all times ,
understanding attention is a key to an understanding of almost any form of cognition . to date , however , the mechanisms by which attention operates are not fully understood .
one persistent debate in this area concerns the role of inhibition of irrelevant stimuli as one form of top - down control over attention . whereas some researchers believe that inhibition of attention is a response to initial capture of attention and , thus , follows preceding attentional capture by an irrelevant stimulus
, other researchers believe that active inhibition of attentional capture by an irrelevant stimulus is possible right from the start of such a stimulus .
to start with the first proposition , many researchers argued that salient objects capture attention in a bottom - up way ( cf . [ 3 , 4 ] ) .
according to the salience model of attention , any visual stimulus that stands out among its surroundings by a strong feature contrast in color , orientation , or luminance may capture attention in an exogenous stimulus - driven way , regardless of the current goal of the observer ( cf .
[ 5 , 6 ] ) . in line with this prediction , an irrelevant color singleton distractor that is a stimulus with a color different from its surrounding stimuli , such as one green circle among several red circles , interferes with finding a shape - defined target stimulus ( i.e. , the one rectangle among several circles ) ( cf . ) .
this is the case although attending to the specific color of the singleton is neither necessary nor helpful for finding the target .
such findings have been attributed to the bottom - up capture of attention by an irrelevant singleton . as a consequence , attention
is thought to first be distracted away from the relevant target and only later be redirected towards the target .
this is possible after a deliberate inhibition of the irrelevant stimulus , allowing attention to disengage from the distractor .
findings by kim and cave are in general agreement with this late - inhibition or disengagement hypothesis .
these authors used a probe stimulus as a second target in a combined search and probe reaction task .
critically , the probe was shown after the search display with the probe either at the position of the search display 's shape - defined target or at the position of the search display 's color - singleton distractor . with an interval of 60 ms between search display and probe , kim and cave observed ( nonsignificantly ) faster responses to probes at color - distractor positions than to probes at shape - target positions . however , with a cue - target onset asynchrony ( ctoa ) of 150 ms between the color - singleton distractor ( cue ) and the probe ( target ) , responses to probes at the position of the color - singleton distractor were significantly delayed relative to responses to probes presented at the location of the shape target .
like theeuwes et al . , kim and cave took their results as an indication of bottom - up capture by the color - singleton distractor with a short ctoa , giving way to disengagement and even active inhibition with a long ctoa . the core notion of the disengagement hypothesis ,
that is , the idea of active inhibition following initial allocation of attention towards a stimulus , is also at the heart of another well - known phenomenon called inhibition of return ( ior ) .
ior denotes the finding that attracting visual attention toward one position in space by a cue delays a second attention shift to the same position at a later point in time [ 810 ] .
ior is observed with long ctoas and corresponds to longer reaction times where cue and target are presented at the same position ( sp ) compared to cue and target at different positions ( dp ) .
thus , the idea of stimuli initially triggering attentional capture and later inhibition is a very dominant notion found throughout the attention literature .
however , recent findings by mcdonald et al . and by ansorge et al .
are potentially in disagreement with this late - inhibition or disengagement hypothesis for irrelevant stimuli .
ansorge et al . asked their participants to saccade to one out of four positions , varying randomly from trial to trial ( see figure 1 for an illustration of a similar stimulus and task sequence ) .
prior to the saccades , participants were presented with a relevant or an irrelevant color singleton cue .
participants only had to attend to the relevant cue because this cue indicated the position of a discrimination target later in the trial .
in contrast , the participants were asked to ignore the irrelevant cue : when an irrelevant cue was presented , no target discrimination was required so that it was safe to ignore this cue .
in addition , ignorance of the irrelevant cue was encouraged : because cue and saccade target positions were uncorrelated ( cf . ) and because saccades require a prior attention shift to the target position [ 13 , 14 ] , the participants could fully concentrate on the saccade task and ignore the irrelevant cues completely .
in contrast , the participants were forced to shift their attention to the relevant cue for the encoding of its position for the discrimination task and at the potential cost of a suboptimal preparation of their saccades .
all of these cues were nonpredictive of the saccade target position , and relevant and irrelevant cues had different fixed colors , so that the participants knew exactly which color they had to attend to ( e.g. , red ) and which color they could ignore ( e.g. , green ) . under these conditions , ansorge et al
. studied the time course of selective attentional capture and/or inhibition by looking at the development of the saccadic latencies across the latency distribution , from quick to slow saccades . with a long ctoa , and with relevant cues , ior followed initial capture : initial capture among the fast responses was reflected in quicker saccades to a saccade target at the same position ( sp ) as the cue compared to slower saccades to a saccade target at a different position ( dp ) than the cue . with relevant cues ,
this pattern reversed into ior among the slower responses . in contrast , with a long ctoa and irrelevant cues , inhibition in the form of slower saccades to sp than dp targets was found right from the beginning and without preceding capture effects .
these findings point to a form of proactive inhibition of irrelevant cues , completely preventing attentional capture by the irrelevant cues , rather than late disengagement .
in fact , the only reliable capture effect for irrelevant cues showed up in a condition with a different procedure and no subsequent inhibition ( experiment 4 ) .
thus , no conclusion could be drawn about transitions from capture to disengagement . a recent study by mcdonald et al .
equally found evidence for proactive inhibition of irrelevant stimuli without a trace of preceding attention capture . to discern between capture and inhibition , mcdonald and colleagues used two lateralized components of the event - related potential ( erp ) : the n2pc ( cf .
[ 15 , 16 ] ) or posterior contralateral negativity ( pcn ) and the pd [ 18 , 19 ] .
the n2pc has been widely used to investigate both stimulus - driven capture and top - down contingent capture [ 2125 ] .
importantly , when mcdonald et al . tested for initial capture of attention by irrelevant stimuli , all they found was a pd , that is , evidence for proactive inhibition of the irrelevant stimuli .
this was found after splitting the erps into fast and slow responses : the quickest target responses of the participants indicated proactive inhibition of attentional capture by an irrelevant distractor .
even so , it is not entirely clear whether the findings reflected only early inhibition or whether some capture of the irrelevant singletons occurred before it was suppressed . regarding the findings of ansorge et al .
, these authors used saccadic latencies after relatively long ctoas ( > 200 ms ) .
this method is relatively insensitive to the early attentional effects , so that preceding attention capture even by irrelevant cues might have gone unnoticed ( see their condition with a ctoa of 200 ms ) . regarding the findings of mcdonald et al .
, it is possible that their observations reflected a mixture of weaker capture effects of the irrelevant distractors in some of the trials and of stronger inhibition of distraction in other trials . as a result
, a net inhibitory pd effect could have masked evidence for early capture in the form of an n2pc in the study of mcdonald et al .
at least in the slower responses , there was also clear evidence for this possibility : on slow response trials ( ) there was neither an early distractor ( ) nor a late target n2pc ( ) .
the absence of either n2pc suggests that the target and distractor n2pc wave cancelled each other out ( )
thus , to test once more whether capture by irrelevant cues could precede subsequent inhibition , we combined the methods of ansorge et al .
and of mcdonald et al . , using two different measures for early and late effects based on the very same trials .
late inhibition was assessed through the presence of ior in saccadic reaction times after a sufficiently long ctoa of 1 s. this procedure allows for the registration of an early capture effect by all singletons , without masking by a concomitant n2pc by the targets . in this situation ,
in addition , we conducted a median - split of the erps on the basis of whether a fast or a slow saccade was given that allowed us to test whether the fastest responses were associated with a pd component , similar to mcdonald et al . .
the aim of the current experiment was to investigate the connection between attention capture by relevant and irrelevant stimuli and ( subsequent ) inhibition .
we examined within the same trials ( 1 ) the amount of initial capture of attention by an irrelevant cue and a relevant cue in the form of the n2pc and ( 2 ) the amount of inhibition in the form of an early pd and late saccadic inhibition of return . in detail , in the first display of each trial , we used one of two color - singleton cues : the first cue was relevant in half of the trials and it was irrelevant in the other half of the trials .
a relevant first cue had a fixed color ( e.g. , it was green ) , known to the participant .
the participant had to look for the relevant first cue and importantly , also covertly , attend to its location because it indicated the position of a subsequent discrimination target .
we call this cue relevant to make clear that its color serves the same purpose as a searched - for feature of a target in a standard color - search task .
in contrast , the irrelevant first cue had a different color ( e.g. , it was blue if the relevant cue was green ) , also known to the participants .
therefore , the participants could have ignored this cue completely and were not required to shift spatial attention to its location .
we call this cue irrelevant because its color served the same purpose as the color of an irrelevant distractor in a visual search display .
that is , the color of the irrelevant first cue indicated with 100% certainty that this stimulus could be safely ignored . to test ior
after the first cue , our participants had to encode the position of a second singleton cue in a second display for a saccade in a subsequent third display ( see figure 1 ) .
importantly , positions of the first cue and of the second saccade cue were uncorrelated . because the participants have to allocate their attention to the position of the saccade target ( cf .
[ 13 , 14 , 28 , 29 ] ) , they had to disengage their attention away from any first cue and to redirect it towards the position of the second cue in anticipation of the saccade target . also , the ctoa was 1 s long allowing for both inhibition ( or disengagement ) of attention and saccadic inhibition ( of return ) .
we therefore expected saccadic inhibition with respect to the position of the first or covert cue ( [ 11 , 30 , 31 ] ; see also ) .
the question is whether with irrelevant first cues a capture effect in the form of an n2pc precedes this inhibition effect or whether inhibition is observed from the start , in the form of a pd .
also , in the relevant condition , an n2pc to the first cue was to be expected because an attention shift to this first cue was required to encode its position .
twelve volunteers participated but one was excluded because her saccade latencies were more than three standard deviations slower than that of the other participants .
the remaining participants ( with a mean age of 25 years and a male / female ratio of 6 : 5 ) reported normal or corrected - to - normal vision . written and informed consent was obtained from each participant before the experiment .
visual stimuli were presented on a 19-inch crt color monitor ( sony multiscan g400 ) , with a screen resolution of 1,024 768 pixels and a refresh rate of 100 hz .
the participants sat at a distance of 57 cm from the screen in a quiet , dimly lit room , with their head resting on a chin rest to ensure a constant viewing distance and a straight - ahead gaze direction .
the first and second displays were presented for 50 ms and the last display for 1 s. all displays were separated by an interstimulus interval of 450 ms , such that the onset asynchrony between two displays was 500 ms .
a gray central fixation cross was presented on a black background ( < 1 cd / m ) , visible throughout each trial .
the first display consisted of six equidistant placeholders , each in the shape of the digital letter 8 ( with a size of 1.7 1 and with stroke strength of .3 ) .
a placeholder was located per each of the positions at 0 , 60 , 120 , 180 , 240 , and 300 from the vertical meridian that is ,
the shape-8s were presented equally spaced on the circumference of a virtual circle centered on the screen , with an eccentricity of 7. five placeholders were presented in gray ( cielab color coordinates : 6.9 , 16.8 ) , and one was presented in a different color , either in green ( cielab : 30.2 , 24.9 ) or blue ( cielab : 46.9 , 89 ) .
it was always shown at one of the four lateral positions but never presented above or below the fixation .
the shape-8s were replaced by three letters e and three digits 3 , in digital notation .
five of these shapes were presented in gray and one was presented in red ( cielab : 47.6 , 41.1 ) .
this red stimulus was the second or saccade cue and it could also only appear at one of the four lateral positions .
the red singleton was called a saccade cue because this second cue served as the cue for the saccade target in the subsequent display .
also , in this display , one figure served as a discrimination target if it had been cued by a relevant first cue ( blue or green cue ) in the preceding display , with relevant first cue color fixed across trials and balanced across participants .
positions of the discrimination target and second ( or red ) cue were uncorrelated across trials . consequently , in 25% of the trials
the discrimination target and second or saccade cue were at the same position ( sp condition ) , and in 75% of the trials they were at different positions ( dp condition ) .
this display consisted solely of six empty circles surrounding the stimulus positions as used in the preceding displays .
the saccade display was presented for 1 s. the color of the first singleton cue in the first screen indicated whether the discrimination task in the second screen had to be performed on a given trial .
for instance , a first green singleton was linked to the discrimination task while a first blue singleton could be ignored , or vice versa . in the discrimination task , participants had to encode and remember the shape of the digit presented in the second screen at the position of the relevant first singleton cue .
this was necessary for the report of this figure at the end of the trials .
as soon as the third display , the saccade display , appeared the saccade had to be executed .
after the saccade was executed , in a relevant - cue trial , participants typed the identity of the discrimination target letter ( i.e. , whether the letter e or the digit 3 was presented ) by pressing the marked buttons # f and # j labeled left and right on a standard keyboard directly in front of the participants .
if no discrimination was necessary ( i.e. , after irrelevant cues ) , this part of the trial was skipped .
participants started the next trial in a self - pace manner , by pressing the space bar .
participants were informed that the color singleton cues could only appear at the four lateral positions on the screen and that the position of the second or saccade singleton cue was independent of the position of the first singleton cue .
blocks consisted of 64 trials and feedback was given about whether the target discrimination was correct and about whether the saccade was registered during the third screen .
altogether ten blocks of trials were conducted , of which the first was training and not analyzed .
each factor combination of the variables discrimination target ( e or 3 ) , first cue position ( above / left , above / right , below / left , and below / right ) , first cue color ( blue , green ) , and second cue 's position ( above / left , above / right , below / left , and below / right ) was equally likely and presented in a pseudorandom order within each block .
saccades were recorded with an eyelink 1000 desktop mount system ( sr research , mississauga , on , canada ) with a 35 mm lens and eyelink software version 4.52 , sampling at 1,000 hz .
a 9-point calibration was used to adjust the eye - tracker before the experiment and in advance of every single block .
saccadic reaction time ( saccadic rt ) was calculated as the time between ( 1 ) the onset of the third display ( with the saccade - target stimulus circle ) and ( 2 ) the time of a local velocity minimum that immediately preceded the point in time at which eye velocity exceeded 80/s .
a saccade counted as correct if it landed in an area of 1.5 around the center of the saccade target .
saccade landing position was calculated as the x - y coordinates of the eye - tracker signal at the time at which eye velocity returned to a presaccadic baseline level .
also , if the eyes started to move earlier than 100 ms after the saccade target , a trial was discarded .
dc - eeg was recorded from 23 scalp electrodes mounted in an elastic cap at standard positions of the extended 10/20 system at sites fpz , f7 , f3 , fz , f4 , f8 , fc5 , fc6 , t7 , c3 , cz , c4 , t8 , cp5 , cp6 , p7 , p3 , pz , p4 , p8 , o1 , o2 , and oz . the continuous eeg was sampled at a rate of 1,000 hz with a digital low - pass filter of 50 hz .
all scalp electrodes were online referenced to a noncephalic sternovertebral site , above the seventh vertebra and the right manilum sternum .
the vertical eog ( electrodes below and above the left eye ) and the horizontal eog ( electrodes at the outer canthi ) were recorded bipolarly , so as to delete trials with eye movements during the critical eeg recording interval .
trials with saccades earlier than 100 ms after the saccade target ( detected with the eye - tracker ) or muscular artifacts ( exceeding 80 v at any electrode ) , as well as trials in which the target was not correctly discriminated , were excluded from analysis .
erps were calculated for 400 ms after the first cue 's onset relative to a 50 msec precue baseline .
n2pc amplitudes in response to the first color cue were calculated separately for left and right and relevant and irrelevant cue , collapsed across all saccade target positions as mean erp amplitudes at locations p3/4 in the 160270 ms interval after cue onset .
a switch box was implemented behind the parallel port of the master to send one unique synchronization trigger every 500 ms ( one for the onset of the first display , one for the second display , and one for the third display in each trial ) in parallel , separately to the two slaves , eye - tracker and eeg recorder . in total , 17.5% of all trials were excluded .
trials with saccades faster than 100 ms and slower than 1 s after the saccade target accounted for 8.1% , trials with saccades towards the wrong target or with muscular artifacts for another 6.4% , and trials with a false identification of the discrimination target for 3% .
to take the dynamics of the saccadic response into account , saccadic rts were sorted and grouped into five percentiles from fast to slow ( cf . ) .
this was done to test our hypotheses about ior with differently fast responses because the amount of capture and of ior does vary over time and an effect that is absent in the average of all responses can well be present when looking at only the faster or only the slower responses ( e.g. , [ 11 , 34 ] ) . as can be seen in figure 2 , from fast responses on the left to slow responses on the right
this was reflected in faster saccadic rts under dp conditions ( broken lines ) as compared to sp conditions ( solid lines ) , more so with the irrelevant cues ( red lines ) than with the relevant cues ( blue lines ) . a repeated - measures anova with the variables position ( same versus different position of first or covert cue and saccade cue / target ) , cue type ( relevant first cue or irrelevant first cue ) , and percentile ( 1st to 5th ) revealed inhibition at the location of the first or covert cue only among the slowest responses in the form of slower saccadic latencies in sp than dp conditions .
this was reflected in a significant interaction of position and percentile , f(4,40 ) = 2.79 , p < .05 . from the 1st to the 5th quintile , saccadic inhibition ( saccadic rt in sp conditions minus saccadic rt in dp conditions ) was 0 ms , 1 ms , 4 ms , 3 ms , and 32 ms ( 1st to 4th quintile , all ts < 1 ; 5th quintile , t(9 ) = 2.29 , p < .05 ) .
in addition , we found faster saccadic rts in trials with a relevant than an irrelevant cue in the first display ( 241 ms versus 273 ms ) , resulting in a marginally significant main effect for cue type , ( 1,10 ) = 4.72 , p = .055 .
there was also a trivial main effect of percentile ( increasing saccadic rts with percentile ) , ( 4,10 ) = 94.56 , p < .01 . further , there was a numerically stronger inhibitory effect on saccades after the irrelevant cue ( 10 ms ) than after the relevant cue ( 2 ms ) , as would be expected based on an active inhibition explanation .
however , the two - way interaction of relevance and position was not significant , ( 1,10 ) = .55 , p = .48 , as was the three - way interaction , f < 1 . in sum , saccadic inhibition was selectively present in the slowest saccades and it was largely independent of the type of cue that was used in the first display .
figure 3 shows erps time - locked to the first cue 's onset at lateral posterior electrodes p3 and p4 contra- and ipsilateral to the first cue , separately for cues with a relevant color ( panel a ) , cues with an irrelevant color ( panel b ) , and difference waves ( i.e. , contra- minus ipsilateral activity for relevant and irrelevant cues , panel c ) .
the differences are depicted together with topographical erp - difference maps for the time window of the n2pc ( 160 ms to 270 ms ) .
all erps are relative to a baseline from 50 ms before the first cue to the onset of the first cue . as can be seen , there was an n2pc in the relevant and in the irrelevant cueing conditions .
also , by looking at figure 3 , it seems as if the n2pc started later and was weaker in the irrelevant than in the relevant cueing condition .
these observations were confirmed in a repeated - measures anova with the variables cue type ( relevant or irrelevant cue ) , laterality ( electrode ipsi- or contralateral to the first cue ) , and hemisphere ( right or left hemisphere ) .
the analysis revealed a significant main effect for laterality , ( 1,10 ) = 7.3 , p < .05 , and a significant interaction of laterality and cue type , f(1,10 ) = 10.14 , p < .01 .
however , if the cue was relevant , the n2pc was stronger ( contra- minus ipsilateral activity : 0.76 v ) and started earlier than if the cue was irrelevant ( .30 v ) , as was shown in section 2.2.3 .
we were concerned that the choice of the electrode locations of the n2pc might have been unfortunate .
therefore , we repeated our major analysis of the n2pc in a repeated - measures anova with the additional variable site ( p3/p4 , p7/p8 , and o1/o2 ) and the variables cue type ( relevant or irrelevant cue ) and laterality ( electrode ipsi- or contralateral to the first cue ) as before .
besides replicating the main effect of laterality , f(1,10 ) = 6.86 , p < .05 , and an interaction of laterality and cue type , f(1,10 ) = 5.56 , p < .01 , there were no significant main effects , all fs < 1.40 and all ps > .28 , and no significant interactions including the three - way interaction of site , cue type , and laterality , all fs < 2.10 all ps > .15 .
in addition , the anova was also repeated with the erps pooled across p3 , p7 , and o1 ( for the left side ) and across p4 , p8 , and o2 ( for the right side ) .
this anova also confirmed a laterality effect , ( 1,10 ) = 6.86 , p < .05 , and an interaction of laterality and cue type , f(1,10 ) = 5.56 , p < .01 , and no main effect of cue type , f < 1 . to demonstrate the earlier onset of the n2pc with relevant cues than with irrelevant cues , we split the n2pc window into an early phase ( 160 ms to 215 ms after the cue onset ) and into a late phase ( 215 ms to 270 ms after the cue onset ; cf . ) . in the early window ,
an anova revealed a significant two - way interaction of laterality and cue type , ( 1,10 ) = 30.17 , p < .01 .
post - hoc t - tests revealed that the contra - to - ipsilateral negativity difference ( .78 v ) was only significant in the relevant condition , ( 10 ) = 4.33 , p < .01 , but not in the irrelevant condition ( .02 v ) , t(10 ) = .08 , p = .93 .
a similar anova of the late time window only led to a main effect of laterality , ( 1 , 10 ) = 8.10 , p < .05 .
the contra - to - ipsilateral negativity difference was about similar in relevant ( .77 v ) and irrelevant ( .66 v ) cueing conditions .
there was neither a main effect of cue type , nor of hemisphere , nor any interaction between the variables , all other fs < 2.10 all ps > .18 .
recently , mcdonald and colleagues showed that irrelevant distractors elicited a pd among the fastest responses .
we therefore also repeated our anova of the activity at p3 and p4 , with only the fastest 50% of the saccades and the two within - participant variables cue type ( relevant or irrelevant cue ) , and laterality ( electrode ipsi- or contralateral to the first cue ) .
again , activity was more negative at contra- than ipsilateral electrodes , ( 1 , 10 ) = 11.16 , p < .05 .
this time , however , the interaction was far from significant , f < 1 . in contrast to the findings of mcdonald et al . , a more prominent n2pc rather than a pd was observed with the irrelevant singleton cues during the fastest responses .
in the present study , we tested whether irrelevant cues were proactively inhibited or whether they captured attention before being inhibited . in line with the latter possibility , relevant , and importantly also irrelevant , cues elicited an n2pc and both stimuli led to inhibition of saccades 1 s after the cues .
this was reflected in slower saccadic rts to targets in sp than dp conditions . in other words
, we found the typical ior effect , an observation in line with the late inhibition or disengagement hypothesis of theeuwes et al . .
this finding is also in agreement with prior findings of ansorge et al . with relevant cues . in their study
, these authors found a capture effect of the relevant cues when a ctoa of 200 ms was used .
ansorge et al . also observed that ior started earlier with an irrelevant cue than with a relevant cue .
this particular finding could not be observed in the present study . in the present study , among the slowest responses , ior with irrelevant cues
this latter finding is thus also not so well in line with theeuwes et al .
's disengagement theory , according to which one would have expected stronger disengagement or ior after irrelevant than after relevant cues . according to disengagement theory , only the stronger disengagement of attention that follows irrelevant cues accounts for seemingly stronger capture effects by relevant than irrelevant cues . clearly , this prediction of the disengagement theory was not confirmed .
in contrast , our results suggested a mixture of early capture differences with more capture by relevant than irrelevant cues and a later disengagement effect that was numerically stronger with irrelevant than relevant cues , as two sources contributing to stronger capture effects by relevant than irrelevant cues .
concerning stronger capture by relevant than irrelevant cues , this was reflected in the n2pc .
when we looked at the n2pc as an index of the initial capture of attention , we found a larger overall n2pc .
this reflected on average an earlier start of the n2pc elicited by the relevant cue .
these findings are in line with prior findings showing an earlier or temporally less variable capture effect and often even a selective capture effect for top - down matching than nonmatching cues [ 12 , 21 , 23 , 35 , 36 ] .
this difference in capture for top - down matching as compared to nonmatching cues is typically assumed to reflect either of two processes : selective top - down tuning to sets of features so that initial capture is restricted to the cues matching the set [ 12 , 37 ] or less inhibition of attention captured by the top - down matching cue [ 1 , 38 ] . with the current procedure , we can not decide which of these interpretations holds true , that is , whether the temporally more variable or trailing onset of the n2pc by the irrelevant cues reflected less initial capture by these cues or a combination of initial capture by the irrelevant cues and proactive inhibition of the irrelevant cues . with respect to the latter ,
however , we did not find any evidence for strong early proactive inhibition of the irrelevant cues in the form of a pd .
the trailing of the n2pc for irrelevant cues might be a tentative hint for some proactive inhibition . without any proactive influence
, one would expect similar onset times of the n2pc for relevant and irrelevant stimuli ( although the initially smaller n2pc for irrelevant stimuli may camouflage its early onset ) .
in particular , prior studies found proactive inhibition in the form of a pd when only looking at the fastest responses .
in contrast to this finding , early or proactive inhibition was not associated with the fastest responses in the present study .
this was evident when we sorted the erps as to whether they were recorded in a trial with a quick or slow saccade : among the fast saccades , the n2pcs of irrelevant and relevant cues became even more similar .
this means that in the present study , more proactive inhibition would have counteracted the irrelevant cue 's n2pc onset in the trials with the slower saccades . which factors might account for the differences between the present study and the previous study by mcdonald et al . ?
to reconcile the different findings , results from kiss and colleagues might be of interest .
these authors presented target and distractor simultaneously ( similar to ) and found proactive inhibition of the irrelevant distractor in the form of a pd when the display was shown for 200 ms but an n2pc plus subsequent inhibition ( again in the form of a pd but occurring at a later point in time ) when the display was presented until a response was given .
this might indicate that the irrelevant distractor elicits an n2pc and captures attention when the participants have time for their attention to shift to the target so that the distractor - elicited capture is not masked by a concomitant target - elicited n2pc .
this might also explain why we found an n2pc of the irrelevant cues whereas most contingent - capture studies did not find any evidence for capture by irrelevant singleton distractors ( e.g. , [ 21 , 39 ] ) .
with respect to the finding of an n2pc to the irrelevant cue in the present study and its absence in prior studies , a few other procedural differences might also play a role .
first of all , the relevant cue was 100% valid ( 100% sp ) ; that is , it predicted the discrimination target position with certainty .
although there was no discrimination target in the irrelevant target position it is possible that a bit of the general informative value of the relevant cues spilled over to the irrelevant cues .
in other words , participants might have inadvertently attended to the irrelevant cue on at least some trials , for example , because they were not paying close enough attention to the color of the first cue . in support of this possibility
, it would have been possible to find the relevant cues by the so - called singleton search strategy [ 40 , 41 ] .
in fact , the use of two different relevant colors one ( e.g. , blue ) for the first display 's relevant cue and another one ( red ) for the saccade cue in the second display might have encouraged our participants to use a singleton search strategy rather than a feature search strategy .
a few findings seem to indicate that the use of a top - down set containing two relevant colors leads to the erroneous capture of attention by an irrelevant color - singleton distractor in at least some trials ( cf .
in addition , participants might have actively searched for even the irrelevant cues because these cues informed the participants that they would not have to discriminate between the different target orientations and keep the cue 's position in mind .
the relatively long ctoa might have encouraged this strategy further because it would have allowed sufficient time to first willingly attend to each cue relevant and irrelevant and then to return attention to a neutral position after the irrelevant cue and before the onset of the target . even though this particularity of our procedure might explain why we did find an n2pc for both relevant and irrelevant cues , it is important to note that we were still able to ascertain two things : first , recording eeg we were able to demonstrate capture where behavioral measures only indicated inhibition .
thus , although one might argue that the difference in the way participants processed relevant and irrelevant cues in our study was only small , our eeg measure was definitely sensitive to it . in sum
, we might not have ended the debate over early proactive inhibition for complete prevention of capture once and for all with our study .
however , we provide one more piece in the puzzle and another demonstration of the usefulness of combining eeg with behavioral measures to obtain a more complete picture of the processes engaged through a given paradigm . a further point that needs
, it would be strange if different degrees of initial capture by relevant versus irrelevant cues ultimately lead to relatively similar degrees of ior by these stimuli .
however , researchers had argued from very early on that capture and certain forms of inhibition could be partly independent processes . today , it is clear that nonattentional factors like motor inhibition and sensory habituation can also contribute to inhibition [ 8 , 49 , 50 ] .
therefore , it is in principle possible to find similar degrees of late inhibition after different degrees of capture [ 5153 ] or even more inhibition following less capture by an irrelevant stimulus .
along similar lines , prinzmetal et al . reported that attention capture and ior are differentially modulated by , on the one hand , the number of potential target locations and , on the other , the presence of distractor stimuli in the target display .
dissociations of attention capture and ior are also in line with neurophysiological observations suggesting that the two effects arise at different stages of processing and may therefore be modulated differentially ( e.g. , ) . in more functional terms , prinzmetal et al .
recently suggested that attention capture may best be described by a serial search mechanism , reminiscent of the attentional spotlight that ( at least for top - down matching cues ) is first allocated to the cued location and has to be redirected on invalid ( dp ) trials .
ior , however , may better be accounted for by a decision process in a competitive accumulator model in which the decision to respond to a particular location previously visited by attention is systematically delayed ( see also ) . in conclusion , the two mechanisms proposed for attention capture and ior are very distinct , supporting the possibility for dissociations .
previous studies such as gibson and amelio failed to find any evidence for ior with color singletons , a result that was ascribed to the special role of abrupt onsets for the occurrence of ior . here , we show that relevant and even irrelevant color singletons lead to ior when an eye movement instead of a manual response is used and when the saccadic rt distribution is taken into account . in line with this interpretation , godijn and theeuwes and more recently priess et al . and ansorge et al
in conclusion , in line with the late inhibition or disengagement theory , we have shown that the irrelevant and the relevant distractor first both captured attention ( reflected in their n2pcs ) before they were actively inhibited ( reflected in saccadic ior ) .
this lack of proactive inhibition was also found if only the fastest responses were analyzed .
however , we found little indication that ior was stronger after irrelevant than relevant cues . therefore , it is not likely that disengagement was the only responsible process
. early inhibition ( among the slower responses ) or contingent capture must have also contributed to the n2pc differences between relevant and irrelevant cues .
Output:
| attentional capture is usually stronger for task - relevant than irrelevant stimuli , whereas irrelevant stimuli can trigger equal or even stronger amounts of inhibition than relevant stimuli .
capture and inhibition , however , are typically assessed in separate trials , leaving it open whether or not inhibition of irrelevant stimuli is a consequence of preceding attentional capture by the same stimuli or whether inhibition is the only response to these stimuli . here
, we tested the relationship between capture and inhibition in a setup allowing for estimates of the capture and inhibition based on the very same trials .
we recorded saccadic inhibition after relevant and irrelevant stimuli . at the same time , we recorded the n2pc , an event - related potential , reflecting initial capture of attention .
we found attentional capture not only for , relevant but importantly also for irrelevant stimuli , although the n2pc was stronger for relevant than irrelevant stimuli .
in addition , inhibition of saccades was the same for relevant and irrelevant stimuli .
we conclude with a discussion of the mechanisms that are responsible for these effects . |
PubmedSumm118770 | ***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: mucilage compounds are pharmaceutically important polysaccharides that have an extensive range of applications , including binding agents , thickeners , water retention agents , emulsion stabilizers , suspending agents , disintegrates , film formers , and gelling agents .
a historical approach to medical science written by iranian scholars could help in identifying excellent ideas and provide valuable information in this field for proper application .
the aim of the current study was to introduce some mucilage uses derived from traditional persian medicine ( tpm ) .
in this literature review , we assessed a few main traditional manuscripts of iranian medicine , including the books al havi , canon of medicine , qarabadine - kabir , zakhireh - ye khwarazm shahi , tuhfat ul - momineen and makhzan - ul - adwiah . the word loab in the aforementioned books were searched and all data about mucilage compounds were collected .
the use of medicinal plants containing mucilage in iran dates back to ancient times . in traditional persian manuscripts , mucilage is one of the most cited applications of medicinal plants for therapeutic objectives .
there are various mucilage - producing plants in tpm such as malva silvestris , linum usitissimum , althaea officinalis , plantago psyllium , descureania sophia and ziziphus vulgaris .
they have been used traditionally via oral or topical routes for respiratory , gastrointestinal , urinary , musculoskeletal , and genital systems as well as skin disorders .
a scientific assessment of these valuable manuscripts would provide a better insight into the thoughts of the past sages and applicable for clinical use of the mucilage compounds .
Output:
| background : mucilage compounds are pharmaceutically important polysaccharides that have an extensive range of applications , including binding agents , thickeners , water retention agents , emulsion stabilizers , suspending agents , disintegrates , film formers , and gelling agents . a historical approach to medical science written by iranian scholars could help in identifying excellent ideas and provide valuable information in this field for proper application .
the aim of the current study was to introduce some mucilage uses derived from traditional persian medicine ( tpm).methods : in this literature review , we assessed a few main traditional manuscripts of iranian medicine , including the books al havi , canon of medicine , qarabadine - kabir , zakhireh - ye khwarazm shahi , tuhfat ul - momineen and makhzan - ul - adwiah .
the word
loab in the aforementioned books were searched and all data about mucilage compounds were collected.results:the use of medicinal plants containing mucilage in iran dates back to ancient times . in traditional persian manuscripts , mucilage is one of the most cited applications of medicinal plants for therapeutic objectives .
there are various mucilage - producing plants in tpm such as malva silvestris , linum usitissimum , althaea officinalis , plantago psyllium , descureania sophia and ziziphus vulgaris .
they have been used traditionally via oral or topical routes for respiratory , gastrointestinal , urinary , musculoskeletal , and genital systems as well as skin disorders .
certain applications are unique and promising for today s chronic ailments.conclusion:a scientific assessment of these valuable manuscripts would provide a better insight into the thoughts of the past sages and applicable for clinical use of the mucilage compounds .
this may lead to research opportunities in the future . |
PubmedSumm118771 | ***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: every year , influenza a ( ia ) and b ( ib ) viruses co - circulate from late fall through to early spring , causing respiratory tract infections among persons of every age group with highest rates of illness in children .
severe infections often cause death due to bacterial superinfection . in immunocompromised patients , invasive pulmonary aspergillosis ( ipa )
nevertheless , little is known about the association between invasive fungal super - infections and influenza . since the introduction of multiparameter molecular assays for the detection of respiratory agents
, it is clear that viral infections may trigger the development of fungal superinfections in both immunocompromised and non - immunocompromised patients .
these superinfections occur predominantly after ia infections , whereas the exact role of an ib infection in the pathogenicity and its complications are less clear . in our opinion
, this case proves that an ib virus infection may equal the severity of an ia infection .
critically ill patients are prone to develop disturbances in immunoregulation during their stay in the intensive care unit ( icu ) , which render them more vulnerable for fungal infections .
risk factors such as chronic obstructive pulmonary disease , prolonged use of steroids , preceding viral infection , advanced liver disease , chronic renal replacement therapy , near - drowning and diabetes mellitus have been described .
written consent from the patient s next of kin to publish this case report has been provided .
a previously healthy 51-year - old woman , without known comorbidity or risk factors for complicated influenza , was transferred from a regional hospital .
three days earlier , she had symptoms of a general malaise with myalgia , fatigue , nausea , dizziness , hyperventilation , no fever , but with diffuse severe pain .
a transthoracic echography showed a hypertrophic diffuse hypocontractile left ventricle , a left ventricle ejection fraction of 40% , a limited pericardial effusion without impairment of the myocardial contractility , and no evidence of a valvular disease . as she became hemodynamically unstable , acetylsalicylic acid 1 g iv q.i.d .
, methylprednisolone 40 mg / day and inotropic support were started . during icu admission ,
c - reactive protein was 2.4 mg / dl , urea 101 mg / dl , creatinine 1.17 mg / dl , glomerular filtration rate 49 ml / min/1.73 m , creatine kinase 166,752 u / l , platelets 115 10/l , leukocytes 16.7 10/l ( 85% neutrophils ) , d - dimer 1,268 ng / ml , potassium 5.76 mmol / l , calcium 3.1 meq / l , troponin t 234 ng / l , aspartate transaminase 2,323 u / l , alanine transaminase 851 u / l , and myoglobin 91,180 g / l .
arterial blood gas determination revealed a ph of 7.36 , po2 of 92.1 mmhg , o2 saturation of 96.0% , and a pco2 of 32.4 mmhg .
initially , the chest x - ray showed no abnormalities ( figure 1 day 1 ) .
she was admitted in severe organ failure ( multiple organ failure ) , and shortly after developed severe respiratory distress ( acute respiratory distress syndrome [ ards ] ) .
after a failed trial of non - invasive ventilation , she became hypoxic and hypercapnic and was intubated . on day 3 ,
a respiratory taqman microarray for the detection of 31 respiratory pathogens revealed a strong ib rna signal in a nasopharynx sample .
the influenza strain was typed by the national reference laboratory ( institute of public health , brussels , belgium ) and belonged to the yamagata lineage .
continuous venovenous hemofiltration ( cvvh ) , meropenem 1 g iv t.i.d , and oseltamivir 75 mg orally b.i.d . were administered . on day 3
, renal failure forced us to reduce the oseltamivir dose to 75 mg every other day .
eventually , oral oseltamivir dose was replaced by 40 mg iv b.i.d . in compassionate use for a total of 14 days .
five days after admission , aspergillus fumigatus was cultured from bronchial aspirations . a loading dose of 6 mg / kg voriconazole followed by 4 mg / kg b.i.d .
maintenance and caspofungin with a loading dose of 70 mg followed by 50 mg once a day was started . during the entire icu
stay , no bacteria were cultured from respiratory samples . on day 10 , a muscle biopsy was performed .
an autoimmune necrotizing myopathy could not be excluded , and there were no arguments for a classic metabolic or mitochondrial myopathy .
autoimmune serology was negative , and there was no evidence of any recent infection due to cytomegalovirus , epstein
barr virus , coxsackie virus , hepatitis c virus , parvo b19 virus , or toxoplasma gondii . however , a repeat broncho - alveolar lavage ( bal ) confirmed the strong ib rna signal .
bronchoscopy showed white - yellow cauliflower - shaped budding as well as soft plate - shaped plaque - like elevations at the distal trachea , carina , and the lower airways .
histopathology of the biopsies showed necrosis , massive presence of hyphae , and very little remaining squamous endothelium .
on the other hand , the index in bal determined on days 11 and 16 was 7.8 and 10.9 , respectively .
serum voriconazole levels determined on days 14 and 20 were 2.9 and 8.7 g / ml , respectively . from day 7 , development of pleural effusion with bilateral basal compressive atelectasis of the lower lobes and diffuse alveolar infiltrates over both lungs were noted , suggestive for ards or overwhelming pneumonia . after 2 weeks , bilateral confluent parenchymal shadowing over the entire lungs ensued , with signs of lung edema ( figure 1 ) .
poor oxygenation , refractory to nitrous oxide ventilation , and prone position led to extracorporeal membrane oxygenation ( ecmo ) , and the administration of intravenous immunoglobulin ( ivig ) .
finally , after 22 days without any clinical improvement as well as the development of massive lung edema , all efforts were ceased and the patient died .
, the antigenic drift of ib appears more slowly , does not undergo an antigenic shift , and therefore never causes pandemics .
ib has had an evolution into two distinct circulating lineages : b / victoria lineage and b / yamagata lineage.1,2 except for seals , humans are the only animal ib reservoir .
ib causes infection of the tracheal mucous glands and respiratory bronchial epithelium , but not of the alveolar endothelium.1,2 the capability of an influenza virus to infect epithelial cells of the upper or lower respiratory tract is dependent on the virus hemagglutinin ( ha ) and the cellular receptors on the respiratory epithelium.1 the ib ha and neuraminidase are heavily glycosylated , bind collagenous lectins in lung surfactant , and are then readily cleared from the lungs .
the respiratory tract cellular receptor preference of influenza virus may also play an important role in localization of the infection .
the yamagata virus lineage predominantly bind to -2,6-linked sialic acids , which are mainly present in the upper respiratory tract .
although victory lineage virus also cause mainly upper respiratory tract infection , some viruses are able to bind both -2,6- and -2,3-linked sialic acids.1,2 therefore , ib is probably only involved in infection and inflammation of the upper respiratory tract , in contrast to ia which also destroys the alveolar endothelium of the lower respiratory tract.13 consequently , during an ib infection , the bronchial ciliary epithelium is stripped , local hemorrhages and necrosis may occur , possibly leading to superinfections by bacteria or fungi . furthermore , ia infections are also responsible for cell - mediated defects and secondary leukopenia , which further may predispose infected patients to invasive fungal infections.4 ia viruses may cause mild to fulminant and fatal respiratory infections . for a long time ,
ib was considered to be less pathogenic than ia . however , there is now convincing evidence that ib may cause equally serious infections.1,3 this statement is supported by similar hospitalization rates , and comparable morbidity and mortality figures .
it is currently assumed that infections caused by ib viruses are commonly milder than a / h3n2 infections , but more virulent than seasonal a / h1n1 infections.13,5 epidemiologic surveillance indicates that , at the age of 7 , every child has antibodies against at least one ia strain.1,6 between 2004 and 2013 , the average percentage of circulating ib viruses in the northern hemisphere was 21.4% .
however , there is considerable variation among different epidemic seasons , ranging from < 1% to > 60%.7 between 2004 and 2012 , 27%38% of us influenza - associated pediatric deaths were attributed to ib , while this only corresponded to 18%26% of all circulating viruses.2,8,9 about half of these children did not have any known medical conditions.8 therefore , children and adolescents may experience higher ib attack rate than adults , and infections may be more severe.1,2,8 an influenza virus infection typically presents as general malaise with fever , headache , cough , and rhinorrhea .
most cases present as a mild upper respiratory infection or a primary viral pneumonia / pneumonitis .
gastrointestinal complaints , including vomiting , diarrhea , and abdominal pain , usually occur in young children.6,9 diffuse myalgia , occurring before or simultaneously with the systemic symptoms , may also be a common initial complaint .
influenza infection complications include sinusitis , otitis media , exacerbation of underlying medical conditions , secondary bacterial pneumonia , and co - infections with other viral or bacterial pathogens .
non - pulmonary complications of influenza include myositis , myocarditis / pericarditis , encephalopathy , transverse myelitis , and reye s syndrome .
the complications are observed in all age groups , but more frequently in school - aged children.6 muscle involvement is greater with ib than ia virus .
this phenomenon is not yet fully elucidated , but glycoprotein ( nb ) encoded by the viral rna is suspected to be responsible for the muscle tropism .
nb is an integral component of the ib virion membrane , which may have a role in viral entry and may render ib more myotropic than ia.1,5,6,9 myositis differentiates from myalgia by its later and sudden onset , usually 15 days , more focal location , and greater intensity.6,9 myositis occurs in , respectively , 6% and 34% of children with an ia and ib infection .
tenderness on palpation and gait difficulties are present.10 the diagnosis is usually established by clinical history , presence of influenza in the community , and detecting influenza virus in respiratory samples
. a muscle biopsy is not routinely recommended , and patients recover without the need for neuraminidase inhibitors.6,10 myocarditis is very rarely diagnosed in adults and is mostly associated with ia.11,12 there is a sudden onset of the disease .
echocardiography reveals normal ventricular dimensions , a strong left ventricle dysfunction , and a thickened left ventricular wall is noticed.11 in a recent publication on fatal ib virus infections , the mean age was 11 years , and 78% of them were < 18 years old .
cardiac injury was seen in 20 of the 29 ( 69% ) autopsies , predominantly in patients younger than 18 years .
significantly fewer patients < 18 had a secondary bacterial infection , mostly with staphylococcus aureus , compared with patients over 18 , respectively , 24% and 82% .
therefore , these results indicate that in immunocompetent children , fatal viral infections may occur in the absence of a secondary bacterial infection.2 the treatment of influenza - associated myocarditis is supportive , with early initiation of ecmo.12 rhabdomyolysis involves a rapid dissolution of damaged skeletal muscle , with intracellular muscle components release .
the disease can range from an asymptomatic to a life - threatening condition , associated with acute renal failure ( arf ) , and disseminated intravascular coagulation.13 in severe rhabdomyolysis , the massive amounts of myoglobin released by necrotic myocytes exceed the binding capacity by albumin .
myoglobin is filtered by the glomeruli and reaches the tubules , where it can induce renal dysfunction.14 rhabdomyolysis may be the consequence of both viral and bacterial infections and non - infectious causes.13 the classic triad of myalgia , weakness , and myoglobinuria is only observed in ~10% of patients .
over 50% of the patients have discolored urine as single clinical finding . in 10%40% , patients develop arf ; in children , this may be up to 50% .
so far , little is known about influenza - associated rhabdomyolysis ( iar).15 a study showed that influenza viruses account for 42% of all rhabdomyolysis cases . in 300 cases of influenza myositis ,
3% was accompanied by rhabdomyolysis.6 in both children and adults , rhabdomyolysis was more frequently caused by influenza a. iar may be complicated by the development of a compartment syndrome . while myositis appears more in boys , girls are more prone to develop rhabdomyolysis.6 a muscle biopsy may exclude alternative non - infectious causes , but usually influenza rna is not recovered . therefore , the cause of muscular inflammation or destruction can be derived from the identification of ib in respiratory aspirates during sickness.6,14 rhabdomyolysis treatment is mainly supportive and aiming at arf prevention , usually by using hemodialysis , iv fluid administration and , in severe cases , fasciotomy and ecmo.12,14 the effectiveness of a short course of very high doses of methylprednisolone in rhabdomyolysis treatment has not been established yet , but it was successful in a patient with post cytomegalovirus infection rhabdomyolysis.16 finally , central nervous system ( cns ) complications after an influenza virus infection are very rare , and a variety of cns manifestations may be observed .
seizures ( 80% ) and acute necrotizing encephalopathy ( ane ) are the two most common influenza - related cns complications.17 all age groups are affected .
mortality is ~7% and is higher in adult patients . complications usually appear in conjunction with a recent respiratory infection . in the presence of ane symptoms
occur early , and the clinical course progresses rapidly to coma and death within 23 days . except for a slightly elevated protein concentration in cerebrospinal fluid ,
no abnormalities are found in 90% of the patients.1719 treatment of cns complications is mainly supportive , with control of intracranial pressure , anti - epileptics for seizure control , management of brain edema , and the addition of antiviral treatment with oseltamivir.18 treatment of severe ib infection is essentially the same as for an ia infection , with neuraminidase inhibitors oseltamivir , peramivir , laninamivir , and zanamivir.20 in europe , oseltamivir and zanamivir are the only neuraminidase inhibitors available . regarding the disappearance of fever and shedding of the virus from the respiratory tract , oseltamivir is believed to be less active against ib and influenza a / n1 subtypes , while isolates of the influenza a / n2 subtype were more sensitive.21,22 the amino acid homology between ia and ib neuraminidase is only 30% .
the emergence of viral resistance is a serious concern , as far less is known regarding the ib resistance markers.2 zanamivir , on the other hand , seems to be more active on ib but is only available for inhalation therapy or iv administration in compassionate use and is not used as first - line treatment.2,22,23 the general recommendation is to start oseltamivir within 48 h of symptom appearance .
however , some recent observational studies reported that oral oseltamivir treatment started even 45 days after onset in hospitalized patients with suspected or confirmed influenza is also associated with a lower risk for severe outcomes.20,23 furthermore , viral shedding in ia infection peaks during the first 2 days of illness , whereas viral shedding already increased 2 days before the onset of symptoms in ib infection and is more prolonged in contrast to ia.24 consequently , ib - infected patients are contagious before symptoms appear , so more subsequent cases may develop .
it remains to be elucidated whether early shedding influences the outcome of patients with severe ib infections under antiviral therapy .
the shedding time may partially explain why ib virus infections respond more slowly to oseltamivir .
however , ib viral clearance and clinical response are faster with zanamivir , and in our opinion , treatment regimens should match the clinical circumstances and may need to be altered.25 the duration of the antiviral treatment is determined by the severity of the illness , immune status , viral clearance , and often lasts longer than 5 days.20 the standard dose of oseltamivir is 75 mg b.i.d . , but up to 150 mg b.i.d .
a doubled dose is usually well tolerated and might be beneficial.26,27 in patients with end - stage renal disease , 75 mg once a day is given orally . in critically ill multiple organ failure patients , physicians may want to avoid overdosing oseltamivir and , therefore , the risk of not reaching adequate plasma drug levels may exist.28 a recent review comparing studies of critically ill patients shows that the oseltamivir absorption is not influenced by the presence of vasopressors or enteral feeding . also , the serum level of oseltamivir carboxylate after a standard dose exceeds by far the pharmacodynamic threshold.23 however , evidence - based data identifying the optimal antiviral dose for severe infections with mof are lacking in patients with ecmo and with continuous hemofiltration .
some studies demonstrated adequate drug concentrations with conventional oral dose therapy , while others noted inadequate drug exposure.28 however , dose reduction may be required for patients receiving continuous renal replacement therapy . despite the fact that compared to healthy patients , ecmo patients have a larger distribution volume , dose adjustment is apparently not necessary.18 in a recent pharmacokinetic study , after only 100 mg oseltamivir iv b.i.d . to a patient under cvvh and ecmo ,
adequate plasma levels were obtained , resulting in declining viral loads and clinical improvement.23,28 it is reasonable to assume that the orally and iv administered oseltamivir in our patient was insufficient to decrease viral shedding rapidly .
therefore , a collaboration between specialists and therapeutic drug monitoring of orally administered oseltamivir is necessary to establish the optimal personalized antiviral therapy.26 also , children shed higher viral loads for a longer period than adult patients.8 the administration of ivig shows significant cross - reactive - specific antibody concentrations against influenza and may serve as an adjuvant in severe infections , particularly in immunocompromised patients and in patients with drug - resistant influenza infections . although promising , the isolated effect of ivig in severe influenza infections is hard to assess , as most patients are simultaneously treated with high - dose oseltamivir.29 respiratory viruses and influenza viruses are easily detected by sampling nasopharynx and throat .
however , a recent publication of critically ill icu patients with laboratory - confirmed influenza showed that sampling the lower respiratory tract may be more predictive of clinical outcome , duration of respiratory support , and length of icu stay than sampling the nasopharynx.30 the association of bacterial superinfections after respiratory virus infections and influenza infections , in particular , is well described .
publications of post - influenza fungal super - infections are less numerous and often stem from before the availability of diagnostics tools for fungal infections such as galactomannan.4,31,32 also , there is no doubt about an association between primary viral and fungal superinfections . with the introduction of molecular assays for the detection of viral respiratory nucleic acids , virus infections
are more rapidly detected , improving the clinical outcome of patients with more accurate patient management .
ipa is often described in severely immunocompromised patients and has a high mortality in this group . in apparently immunocompetent critical ill patients without classical immunosuppression but with potential aggravating factors related to icu admittance , ipa
should also be considered when respiratory viruses have been detected.3,4,3337 in our case report , serum galactomannan remained undetectable during the entire course of the infection .
this is not surprising as the patient was relatively young , immunocompetent , had no medical history , and did not take any medication .
the most probable explanation is a transient methylprednisolone and viral - induced depression of the cell - mediated immunity .
loss of ciliary function of the bronchial tree during acute ib infection may have predisposed the patient to the development of an invasive fungal infection.1,34
a. fumigatus culture turned positive only after 5 days of intubation . despite adequate treatment with voriconazole and association with caspofungin ,
for one , she was young and immunocompetent , and further early admittance to icu , adequate mechanical support , and respiratory stabilization certainly influenced the course of her stay .
unfortunately , we lacked existent information regarding zanamivir / oseltamivir plasma concentrations in this severely infected patient under cvvh and ecmo .
Output:
| our objective is to highlight and focus on post - influenza aspergillosis , triggered by influenza b virus .
this relatively new clinical entity is often associated with a fulminant course of respiratory decline and high mortality . a 51-year immunocompetent woman , without any medical history or risk factors for developing a complicated influenza infection ,
was admitted to the intensive care unit . during admission , she presented with an afebrile flu - like syndrome , myocarditis , rhabdomyolysis , multiple organ failure , and evolved to severe respiratory distress .
the broncho - alveolar lavage contained influenza b rna , and the culture revealed aspergillus fumigatus . despite maximal organ support ,
immunoglobulin , antiviral and antifungal therapy , the patient died .
this case demonstrates that influenza b virus may be life threatening even to immunocompetent adults and may trigger an invasive aspergillus superinfection . |
PubmedSumm118772 | ***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: clin kidney j ( 2015 ) 8 : 265270 and by al shakarchi and inston .
Output:
| thomas inman ( 182076 ) wrote practice two things in your dealings with disease : either help or do not harm the patient , echoing writings from the hippocratic school .
the challenge of practicing safely with the avoidance of complications or harm is perhaps only heightened in the context of modern medical settings such as the haemodialysis unit where complex interventions and treatment are routine .
the current issue of ckj reports two studies aimed at improving the care of haemodialysis patients targeting early use of arteriovenous grafts as access for haemodialysis and the implementation of a dialysis checklist to ensure the prescribed dialysis treatment is delivered .
the further challenge of ensuring that such evidence - based tools are used appropriately and consistently falls to all members of the clinical team . |
PubmedSumm118773 | ***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: consensus guidelines have been drafted by several large international working groups on different occasions in an attempt to standardise the surveillance , diagnosis , and management of hcc . of the major working groups ,
the european association for the study of the liver was the first to establish consensus guidelines on the clinical management of hcc following the barcelona european association for the study of the liver ( easl ) conference in 2000 .
the american association for study of liver diseases ( aasld ) adapted these recommendations to issue a set of consensus recommendations in 2005 .
the asian pacific association for the study of the liver ( apasl ) itself also developed a set of consensus recommendations in december 2008 .
the rationale for a set of guidelines on management of the growing problem of hcc is several fold .
firstly , it aims to maximise healthcare resources when targeting large populations at risk , based on current evidence - based practice .
secondly , it allows for a standardised method of diagnosis in the era of computed tomography ( ct ) and magnetic resonance imaging ( mri ) .
lastly , it provides clinicians with a guide to the treatment of hcc . establishing universal guidelines for imaging diagnosis of hcc can be challenging , particularly in the lesions that do not display classical imaging features .
nevertheless , imaging diagnosis of hcc is important because it is noninvasive , given that the incidence of needle tract tumour seeding following biopsy of hcc is small but not negligible ( overall 2.7% , or 0.9% per year ) , while the risk of significant haemorrhage - related complications following image guided liver biopsy is 0.5% ( based on a retrospective review of 3636 percutaneous core biopsies performed at a single institution ) .
furthermore , it allows for proper delineation of extent of disease , which impacts on the type of treatment , including local ablative therapy , such as radiofrequency ablation , transhepatic arterial chemo - embolisation ( tace ) , surgery or transplant .
it can allow for accurate localisation of tumour foci , making it possible for local ablative therapies and proper surgical planning .
the purpose of this paper is to review the similarities and differences between the more recent guidelines on radiological diagnosis of hcc as proposed by the apasl and the aasld .
the use of imaging in hcc diagnosis can be best divided into two main categories .
the first is in the surveillance of patients at high - risk for developing hcc .
prospective screening of patients at high - risk of developing hcc increases the proportion diagnosed with potentially curable disease .
a screening strategy should focus on those patients with chronic hbv or hcv virus infection that has progressed to cirrhosis since more than 40% of these patients will develop hcc . as for the time interval between surveillance tests ,
both the aasld and apasl recommend measurement of serum alpha - fetoprotein ( afp ) levels combined with grey - scale ultrasound ( us ) of the liver for surveillance of hcc [ 3 , 4 ] at 6-monthly intervals for hbv carriers and patients with chronic hepatitis , since it has been shown on metaregression analysis to demonstrate a significantly higher sensitivity for early hcc with us every 6 months than with annual surveillance [ 8 , 9 ] .
although detailed discussion regarding the serological markers for hcc are beyond the scope of this paper , brief mention needs to be made with regards to afp since it is the single most commonly used serologic marker for hcc . as with all diagnostic tests , the sensitivity profile of afp
is reduced when a higher threshold is applied in order to improve specificity . on its own , afp is not sufficient as a screening test for hcc .
taking the most commonly report cut - off of 20 ng / ml , afp carries a sensitivity of 4165% and a specificity of 8094% . particularly in high - risk patients
combined use of afp monitoring and us is recommended , in patients with chronic hcv [ 15 , 16 ] as well as hbv , where it has been found to reduce mortality ( 3741% ) [ 17 , 18 ] . despite the higher sensitivity and specificity of ct and mri for detection of hcc , these have not been validated for and are therefore not currently recommended for screening .
a feature common to the apasl and aasld guidelines is that the recommendations for imaging diagnosis of hcc are to be interpreted in the context of patients at high - risk for hcc [ 3 , 4 ]
. this would include patients with liver cirrhosis and those with chronic hbv infection without definite cirrhosis .
it is important to make this distinction , since the guidelines may not necessarily apply to the general population .
there is little disagreement between the consensus guidelines of the apasl and the aasld on the definition of imaging features of classical hcc .
the presence of arterial hypervascularity and washout are generally considered to be highly specific for the diagnosis of hcc , and shall henceforth be referred to as
in particular , this enables differentiation from intrahepatic cholangiocarcinoma , which shows delayed enhancement . at the time of the easl guidelines in 2001 ,
the importance of washout was not fully appreciated , hence not included . however , this is now specifically emphasized as a crucial feature in the apasl and aasld guidelines .
arterial hypervascularity is defined as increased enhancement of the lesion in the hepatic arterial phase of imaging relative to the background liver .
this is based on the fact that hcc receives predominant vascular supply via the hepatic artery .
a precontrast and a dynamic postcontrast scan of the liver is necessary to demonstrate this on imaging .
washout of the lesion is based on the fact that hcc contains predominantly arterial blood and so , by the time portal venous and delayed images are acquired , the lesion is observed to be hypoattenuating on ct ( or in the case of us , hypoechoeic and in the case of mri , hypointense ) to the surrounding liver at the portal venous or equilibrium phase .
washout can be explained in terms of tracer kinetic modeling of a lesion with high proportion of intravascular space for demonstration of washout , the delayed phase has been shown to be superior to the portal venous phase , both for ct and mri ; this is estimated at 2 - 3 minutes following injection of intravenous contrast agents [ 23 , 24 ] .
the timing of the scans are important , and this has led to the recommendation that imaging be performed in specialised centers . the presence of elevated afp greater than 200 ng / ml is no longer required under the revised aasld guidelines , as it is recognised that there are inherent false - positives ( in cirrhotic patients ) and false negatives [ 3 , 25 ] .
detailed discussion on the role of afp is beyond the scope of this paper , although the limitations of afp as a serologic marker for hcc has previously been alluded to . despite the abundant use of multidetector row technology
although it has been established in that mri is superior in the detection of hccs , particularly the lesions smaller than 2 cm in size [ 27 , 28 ] , neither the apasl nor the aasld recommends the use of mri over ct for staging of disease . in the study by pitton et al . where direct comparison between mri and 64-row ct , mri was significantly more sensitive in detecting tumour nodules
however , the decision to use mri over ct can be limited by its relatively high cost and technical demand .
most of the differences between the aasld and apasl guidelines for the radiological diagnosis of hcc lie in the approach to lesions that do not demonstrate the classical imaging features of hcc .
the aasld essentially does not recognise use of nonvascular imaging criteria , and in the absence of the classical arterial hypervascularity and venous washout pattern of hcc , further evaluation is necessary . while this makes the aasld guidelines more applicable to transplant guidelines ( milan and ucsf criteria ) , where diagnoses were based on vascular enhancement pattern of hccs [ 30 , 31 ] , it may also lead to understaging of disease .
often , the lesions that do not conform to the classical imaging features are better differentiated and smaller than 2 cm in size .
these early hccs have been shown to contain not only fewer portal tracts but also fewer arterioles .
this is reflected by their atypical imaging appearances , where 87% of well - differentiated lesions and 4162% of lesions
smaller than 2 cm showed either absence of arterial hypervascularity , venous washout , or both ( figure 1 ) [ 33 , 34 ] .
importantly , these are the lesions that should be the target of surveillance and diagnoses , since they can be ablated with high likelihood of cure .
conversely , for the larger lesions , even in the absence of the classical imaging features , size alone is a risk factor . in the series by yu et al . in patients with known hbv - induced cirrhosis , lesions with a spherical contour greater than 2 cm
indeed , the classical enhancement features for hcc in large lesions may be confounded by the presence of central necrosis and lesion heterogeneity ( nodule - in - nodule appearance ) . in the revised aasld guidelines
, lesion size continues to predominate , though less so compared to the earlier edition . in the earlier aasld guidelines , any lesion greater than 2 cm in size and demonstrates classical imaging features can be treated without biopsy . for lesions that were between 1 to 2 cm in size
, two imaging modalities , rather than one , with classical features were needed to confirm the presence of hcc and avoid biopsy .
this has been recently revised such that any lesion larger than 1 cm that demonstrate the classical pattern of hcc can be deemed as such and treated accordingly without biopsy .
this is because as with the larger lesions , the approach of using a single imaging technique for lesions that are between 1 to 2 cm yields acceptable results [ 3739 ] . in the presence of atypical findings from a single imaging test ( ct or mri )
, the aasld recommends a different imaging modality ( ct or mri ) for further assessment .
in which single imaging scans were found to have similar specificity ( 9199% ) to two coincidental positive scans ( 91100% ) with much less resource utilization and higher sensitivity ( 7489% versus 5362% ) .
biopsy restores the specificity of imaging to 100% where any of the findings are atypical .
note that contrast - enhanced ultrasound ( ceus ) is not considered to be specific enough ( besides the fact that the ceus agents are not commercially available in the united states ) and is excluded from the revised aasld guidelines .
even though the majority of cirrhotic nodules smaller than 1 cm are benign , kim et al . found that in patients with mild cirrhosis related to hbv , hccs were present in two - thirds of hypervascular lesions smaller than 1 cm .
as such , in lesions smaller than 1 cm , the specificity of imaging for hcc is limited , and based on aasld guidelines , these can not be regarded as hcc , regardless of the enhancement pattern .
a foreseeable problem with imposing this size criteria is that it can pose dilemma in clinical practice , since it has been shown that subcentimetre lesions can be diagnosed , particularly with mri . instead of aggressively chasing the diagnosis through biopsy for lesions smaller than 1 cm ( which in itself can be technically challenging due to size ) , close interval followup in 3 months using the modality that best depicts the lesion is recommended . here , the guidelines may be debated .
it has been suggested that for among hypervascular nodules smaller than 1 cm , those smaller than 5 mm , are subcapsular in location , wedge shaped , or ill defined ( more likely to represent vascular shunts ) a 6-month followup is sufficient , but when the nodule is round , oval , intraparenchymal , or in a dominant mass ( more suspcious for hcc ) , closer imaging followup at 3-monthly intervals should be performed .
typically , nodules are declared benign only if they regress or remain stable for two years , since hcc nodules can grow very slowly .
it has been shown that kupffer cell density decreases with dedifferentiation of the cirrhotic nodule [ 45 , 46 ] and is reflected by two different classes of imaging contrast agents .
the first is a second generation ceus agent containing perfluorobutane microbubbles ( sonazoid , ge healthcare ) ; its use is currently limited as it is not available outside of japan .
the other is superparamagnetic iron oxide ( spio ) mr contrast agents , namely ferucarbotran ( resovist , bayer ) and ferumoxide ( feridex , amag pharmaceuticals ) .
since normal liver tissue contains kupffer cells , which are in turn part of the reticuloendothelial system , malignant lesions can be reliably differentiated from nontumourous liver based on the fact that they do not contain kupffer cells .
the apasl guidelines basically divides the atypical lesions into those that are hypervascular ( and do not demonstrate washout ) and those that are hypovascular ( and do not show arterial hypervascularity ) . for hypervascular lesions that do not demonstrate washout ,
early hccs can be reliably differentiated from focal nodular hyperplasia and arterioportal shunts based on differential uptake of kupffer - specific contrast agents . on the parenchymal phase of imaging
, hccs should appear as unenhanced areas on ceus and as t2 * -hyperintense lesions on spio - enhanced mri .
however , a foreseeable limitation is in the characterisation of other hypervascular malignancies , such as neuroendocrine carcinoma metastases .
the approach to the hypovascular lesion is a little more complex , while at the same time , the differential list for this includes a larger group of hepatic malignancies , including intrahepatic cholangiocarcinoma and metastases .
basically , if the lesion is initially shown to be hypovascular on ct and mri , ceus may be attempted to demonstrate enhancement in the hepatic arterial phase . if this is shown to be true , the lesion
if kupffer - specific imaging demonstrates a relative lack of uptake , the lesion can be regarded as hcc .
again , the limitation of such an approach is that the other concomitant hypovascular lesions such as adenocarcinoma metastases are not definitely excluded .
although ct arterial portography and ct hepatic arteriography ( ctpa and ctha ) are considered to be significantly more sensitive for demonstrating the early vascular changes in small hccs , these are invasive and the expertise for these procedures is not readily available in many centres around the world . the ensuing sections will briefly review various imaging modalities used in diagnosis and assessment of hcc ; some of these are included in the current apasl guidelines , the rest are meant to inform the reader of recent advances in imaging of hcc that may potentially be integrated into future diagnostic imaging algorithms .
given that the apasl recommends the use of kupffer - specific agents ( sonazoid and spio agents ) for lesion characterisation , a more detailed discussion on the utility of these contrast agents needs to be made .
however , in part because neither sonazoid nor currently commercially available spio agents are approved by the united states food and drug administration ( fda ) for clinical use , these are not included under the diagnostic algorithm by the aasld .
ceus on its own is an accepted imaging modality for hcc diagnosis under the apasl guidelines and this has been validated even for lesions smaller than 2 cm .
jang et al . showed that the sensitivity , specificity , and accuracy of ceus for diagnosing hcc was 87% , 100% , and 93% , respectively , .
inherently , the enhancement patterns of lesions on ceus reflect tumour microvascular morphology , making it a valuable method for predicting the histological grade while providing valuable information for antiangiogenic therapy
. the keys limitations of ceus are that it is operator dependent and has decreased sensitivity in obese patients and lesions far from the skin surface .
furthermore , the phenomenon of washout on ceus is less specific for hcc than it is with ct or mri , due to significant overlap between nearly all malignant and some benign lesions .
washout in ct or mri is determined by contrast dynamics in both the intravascular space and the interstitium whereas ceus washout is predominantly related to contrast dynamics in the intravascular space ( figure 2 ) .
moderately differentiated hcc generally shows classic enhancement features , while well - differentiated and poorly differentiated tumours account for most atypical variations .
adding kupffer - specific phase imaging to ceus protocols may yield additional information that can be used to further assess histologic grades of tumour and enable better characterisation among dysplastic nodules , moderately - differentiated and poorly differentiated hccs .
as with spio imaging , kupffer - specific imaging enables detection of all moderately and poorly differentiated hccs .
the reader should however bear in mind that these findings are read in the context of patients at high - risk for hcc development .
kupffer phase imaging itself remains nonspecific , since even benign lesions , such as haemangiomas , that do not contain kupffer cells , will appear as hypoechoeic on kupffer - specific phase of ceus .
similarly , use of spio has been shown in multiple studies to improve accuracy of mri for detection of hccs .
however , detailed discussion of the spio agents will be avoided since these are currently out of production , except to say that experience with spio agents thus far had been promising and that it potentially improves imaging detection of hccs [ 40 , 53 , 54 ] .
double contrast mri , is technically more cumbersome , even though it appears to increase the tumour to liver contrast to noise ratio , and therefore sensitivity , over multiphasic ct [ 55 , 56 ] routine gd - enhanced mri , or spio - enhanced mri [ 58 , 59 ] . although important for staging and treatment decision making , assessment of portal vein thrombosis for tumour involvement is currently not considered in both the apasl or aasld guideline recommendations .
image guided percutaneous biopsy of suspected portal vein tumour thrombosis is feasible but invasive . it may be possible to apply the same ( aasld or apasl ) criteria used in diagnosis of hcc nodules to the vessel of interest to determine tumour involvement , but this does not appear to have been well studied .
various noninvasive techniques have been investigated , and among them , ceus appears to show fairly good success , superior to that of ct .
ceus itself carries a sensitivity of 88% for diagnosing malignant portal vein thrombosis . combining ceus and ct , sorrentino and colleagues found 100% positive predictive value if both imaging modalities demonstrated arterial hypervascularity within the thrombi . in that study ,
18-fdg pet may discriminate between benign and malignant portal vein thrombi but larger numbers are necessary .
based on the absolute adc values , diffusion - weighted ( dw ) mri shows promise for discriminating between bland and tumour portal vein thrombi , but has not been fully validated .
functional imaging of hcc is fast becoming a reality and a brief mention of some of these techniques shall be made .
hepatocyte - specific gadolinium chelate agents are relatively new and are not currently included in the guideline recommendations .
gadoxetic acid ( gd - eob - dtpa , primovist , bayer ) and gadopentetate dimeglumine ( gd - bopta , multihance , bracco ) are two such contrast agents that have been shown to improve diagnosis of hcc , showing diagnostic performance similar to or better than spio [ 67 , 68 ] and comparable to double contrast mri .
hepatocyte - specific gadolinium chelate agents allow for multiphasic dynamic contrast - enhanced mr imaging to be combined with the hepatocyte - specific phase .
these require delayed scanning of approximately 20 minutes in the case of gd - eob - dtpa and 60120 mins in the case of gd - bopta to provide maximal lesion to liver contrast .
specifically , they may be used to differentiate hccs from the arterial enhancing pseudolesions and are recommended for diagnosis of focal nodular hyperplasia [ 71 , 72 ] . like spio agents , they may allow for characterisation of the degree of tumour differentiation .
gd - bopta - enhanced mri with hepatocyte - specific phase imaging improves diagnosis over routine multiphasic ct or mri , with quoted sensitivity and specificity rates of 97% and 88% , respectively , [ 75 , 76 ] ( figure 3 ) .
gd - eob - dtpa - enhanced mri is also superior to ct , with reported accuracy of 0.88 , compared to 0.74 in ct [ 7779 ] . between the two agents , gd - eob - dtpa was more sensitive than gd - bopta for hcc detection ( 86% compared to 64% ) , perhaps related to the fact that the extent of hepatobiliary uptake is considerably less with gd - bopta ( 5% versus 50% ) .
combining gd - eob - dtpa - enhanced mri and sonazoid ceus detected 73% of the nodules not detectable by multiphasic ct .
it may also be combined with diffusion - weighted ( dw ) mri to improve diagnosis .
however , assessment for lesions smaller than 1 cm can be still poor ( sensitivity of 2943% ) , and hence further experience is necessary with these hepatocyte - specific agents before they are included in imaging guidelines .
dw mri studies the random motion of water molecules and shows promise for detection and characterisation as well as posttreatment assessment of tumours .
it improves mr detection of hccs , particularly in lesions smaller than 2 cm , with sensitivities of 8498% compared to 7685% for multiphasic mri alone [ 8688 ] .
potentially , objective measurement of the apparent diffusion coefficient ( adc ) may allow for distinction between the different tumour grades [ 89 , 90 ] .
it can be combined with spio - enhanced mri , raising sensitivity from 66% to 70% , while maintaining high specificity of 98% .
dw mri also shows potential for assessment of treatment response to local ablative therapies [ 88 , 92 ] .
its role in the diagnostic algorithm is not certain at this point , although , given the promising results and its ease of implementation in routine clinical practice ( due to fast acquisition times , no needs for additional hardware and ease of interpretation ) , incorporation into future guidelines is anticipated .
fluorodeoxyglucose ( fdg ) pet is generally accepted to have low sensitivity ( 5068% ) for intrahepatic hcc [ 9395 ] and is therefore not considered to be useful for diagnosis of hcc , except perhaps in cases of poorly differentiated hcc where it may show better results .
dual tracer imaging with the addition of c - acetate improves sensitivity for intrahepatic disease from 3749% for 18-fdg and 11-c alone to 90% when combined .
the role of 18-fdg is limited to evaluation of extrahepatic disease , with sensitivity of 1384% , depending on the size of the lesions .
newer tracers such as f - choline andf - thymidine have shown slightly better results , but further experience is needed . at present , pet plays a small role in imaging assessment of hcc , but tumour - specific tracers may be the key to its use in future .
this has been paralleled by advancements in us , ct and mri technology , along with development of various kupffer- and hepatocyte - specific imaging contrast agents .
as the treatment of hcc becomes more sophisticated , a greater need for highly accurate diagnosis is necessary .
the consensus recommendations by the aasld and apasl on the radiological diagnosis of hcc underscore the push for noninvasive diagnosis of hcc in avoidance of biopsy . while there is general consensus with regards to the surveillance for hccs in high - risk patients , pertinent differences in the recommendations for imaging diagnosis of hcc exist .
for example , sonazoid is not available for use outside of japan and is therefore unique to the apasl guidelines . in a way
, they also point to differences in practice patterns and the controversies in our understanding of early hcc . the aasld guidelines demand that the classical enhancement features of hcc are demonstrated , accepting that this may limit sensitivity ; biopsy is regarded as a means to restore sensitivity . on the other hand ,
the apasl guidelines emphasizes the use of kuppfer specific imaging techniques to improve diagnostic performance . with rapid and continual improvement in diagnostic imaging modalities and validation of these guidelines , further refinements to the diagnostic algorithm
have fallen out of favour ; spio agents are on the decline due to decreased clinical usage , while double contrast mri , ctha and ctap are cumbersome to perform and not compatible with routine clinical practice .
hepatocyte - specific mri contrast agents are increasingly used in the united states , europe and parts of asia , as well as dw imaging , which is now already widely applied in routine clinical practice , demonstrate great promise to improve current methods of imaging diagnosis . however , before these can be incorporated into the imaging algorithms , validation of their utility is necessary .
similarly , the utility of imaging for other important aspects of hcc management , such as for noninvasive diagnosis of portal vein tumour thrombosis , may also need to be addressed in time to come .
Output:
| consensus guidelines for radiological diagnosis of hepatocellular carcinoma ( hcc ) have been drafted by several large international working groups .
this article reviews the similarities and differences between the most recent guidelines proposed by the american association for study of liver diseases and the asian pacific association for the study of the liver .
current evidence for the various imaging modalities for diagnosis of hcc and their relevance to the consensus guidelines are reviewed . |
PubmedSumm118774 | ***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 total of 58 cid patients , consisting of both as and fmd patients , and a group of 58 healthy volunteers were included in the study .
all participants were evaluated for major cardiovascular risk factors such as diabetes mellitus ( dm ) , history of coronary artery disease ( cad ) , and use of cigarettes or alcohol .
exclusion criteria were history of stroke ; congestive heart failure ( chf ) ; cad ; hypertension ; obstructive sleep apnea ( osa ) ; impaired glucose tolerance ; familial dyslipidemia ; hepatic , henolytic , and renal diseases ; excess alcohol intake ( > 120g / d ) ; morbid obesity ( body mass index [ bmi]>35 kg / m ) ; and vasoactive drug users .
patients with q wave , left bundle block , st segment , and t wave changes specific to myocardial ischemia on electrocardiogram ( ecg ) were also excluded .
the study was conducted in compliance with the world medical association declaration of helsinki : ethical principles for medical research involving human subjects .
approval of the ethics committee was granted , and written informed consent was obtained from all study participants .
study groups were advised to abstain from intense physical activity and alcohol intake for 3 days before biochemical analysis .
venous blood samples were drawn from each participant after 24 hours of fasting to measure biochemical parameters .
for the measurement of serum glucose , spectrophotometry was performed using aeroset automated analyzer ( abbott laboratories , abbott park , il , usa ) .
total serum cholesterol , hdl - c , and low - density lipoprotein cholesterol ( ldl - c ) levels were measured using enzymatic methods .
plasma high - sensitivity - c - reactive protein ( hs - crp ) levels were calculated using enzyme - linked immunosorbent assay ( elisa ) test .
all echocardiographic measurements were made using a ge vivid 7 cardiac ultrasound ( us ) machine ( ge healthcare , horton , norway ) .
standard pulse wave , tissue doppler , m - mode , and 2-d echocardiographic measurements were recorded .
measurements of left ventricular end diastolic diameter ( lvedd ) and left ventricular end systolic diameter ( lvesd , interventricular septal ( ivs ) , and posterior wall ( pd ) thickness were performed using m - mode modality from parasternal long - axis view .
e wave and e wave deceleration time ( dt ) , and early ( e ) and late ( l ) diastolic peak flow velocities were retrieved from transmitral doppler images .
all tissue doppler measurements were made from apical 4-chamber view with 5 mm - sample volume positioned lateral to the edge of mitral annulus . during doppler screening ,
tissue doppler measurements included myocardial early ( e ) , and atrial ( a ) peak velocities ( m / sec ) .
doppler us measurements were recorded during normal respiration . for the evaluation of lv diastolic function , e / a , e / e , and
measurements were performed by a researcher blind to patient data and analyzed by two researchers who were also blind to the study results .
fmd of brachial artery was evaluated with measurement of response to transient ischemia using high - resolution ultrasonography .
measurements were made while all participants were in supine position and rested for 10 minutes .
entire length of brachial artery was scanned using ge vivid 7 175 mhz linear array transducer .
basal diameter of brachial artery was measured , and cuff of sphygmomanometer was wrapped proximal to artery visualized on forearm .
pressure cuff of sphygmomanometer was inflated to 30 mm hg above systolic blood pressure of the patient and left in place for 5 minutes before being deflated .
fmd percentages of maximum diameter of brachial artery during hyperemia triggered by basal and transient ischemia were estimated based on the formula fmd=(maximum brachial artery diameter - basal brachial artery diameter / basal brachial artery diameter)x100 .
descriptive statistics were expressed as medians ( 2575 percentiles ) for continuous variables and frequencies , and as percentages for categorical variables . in intergroup comparisons of continuous variables ,
mann - whitney u test was used , and for categorical variables chi - square test was used .
correlation coefficient and its significance were calculated using spearman s rank correlation test , and p<0.05 was accepted as the level of significance .
a total of 58 cid patients , consisting of both as and fmd patients , and a group of 58 healthy volunteers were included in the study .
all participants were evaluated for major cardiovascular risk factors such as diabetes mellitus ( dm ) , history of coronary artery disease ( cad ) , and use of cigarettes or alcohol .
exclusion criteria were history of stroke ; congestive heart failure ( chf ) ; cad ; hypertension ; obstructive sleep apnea ( osa ) ; impaired glucose tolerance ; familial dyslipidemia ; hepatic , henolytic , and renal diseases ; excess alcohol intake ( > 120g / d ) ; morbid obesity ( body mass index [ bmi]>35 kg / m ) ; and vasoactive drug users .
patients with q wave , left bundle block , st segment , and t wave changes specific to myocardial ischemia on electrocardiogram ( ecg ) were also excluded .
the study was conducted in compliance with the world medical association declaration of helsinki : ethical principles for medical research involving human subjects .
approval of the ethics committee was granted , and written informed consent was obtained from all study participants .
study groups were advised to abstain from intense physical activity and alcohol intake for 3 days before biochemical analysis .
venous blood samples were drawn from each participant after 24 hours of fasting to measure biochemical parameters .
for the measurement of serum glucose , spectrophotometry was performed using aeroset automated analyzer ( abbott laboratories , abbott park , il , usa ) .
total serum cholesterol , hdl - c , and low - density lipoprotein cholesterol ( ldl - c ) levels were measured using enzymatic methods .
plasma high - sensitivity - c - reactive protein ( hs - crp ) levels were calculated using enzyme - linked immunosorbent assay ( elisa ) test .
all echocardiographic measurements were made using a ge vivid 7 cardiac ultrasound ( us ) machine ( ge healthcare , horton , norway ) .
standard pulse wave , tissue doppler , m - mode , and 2-d echocardiographic measurements were recorded .
measurements of left ventricular end diastolic diameter ( lvedd ) and left ventricular end systolic diameter ( lvesd , interventricular septal ( ivs ) , and posterior wall ( pd ) thickness were performed using m - mode modality from parasternal long - axis view .
e wave and e wave deceleration time ( dt ) , and early ( e ) and late ( l ) diastolic peak flow velocities were retrieved from transmitral doppler images .
all tissue doppler measurements were made from apical 4-chamber view with 5 mm - sample volume positioned lateral to the edge of mitral annulus . during doppler screening ,
tissue doppler measurements included myocardial early ( e ) , and atrial ( a ) peak velocities ( m / sec ) .
doppler us measurements were recorded during normal respiration . for the evaluation of lv diastolic function ,
measurements were performed by a researcher blind to patient data and analyzed by two researchers who were also blind to the study results .
fmd of brachial artery was evaluated with measurement of response to transient ischemia using high - resolution ultrasonography .
measurements were made while all participants were in supine position and rested for 10 minutes .
entire length of brachial artery was scanned using ge vivid 7 175 mhz linear array transducer .
basal diameter of brachial artery was measured , and cuff of sphygmomanometer was wrapped proximal to artery visualized on forearm .
pressure cuff of sphygmomanometer was inflated to 30 mm hg above systolic blood pressure of the patient and left in place for 5 minutes before being deflated .
fmd percentages of maximum diameter of brachial artery during hyperemia triggered by basal and transient ischemia were estimated based on the formula fmd=(maximum brachial artery diameter - basal brachial artery diameter / basal brachial artery diameter)x100 .
descriptive statistics were expressed as medians ( 2575 percentiles ) for continuous variables and frequencies , and as percentages for categorical variables . in intergroup comparisons of continuous variables ,
mann - whitney u test was used , and for categorical variables chi - square test was used . correlation coefficient and its significance were calculated using spearman s rank correlation test , and p<0.05 was accepted as the level of significance .
median age of the patient ( cid ) and control group was 37 ( 3147 ) and 39 ( 3741 ) years , respectively , without any intergroup difference .
systolic and diastolic blood pressure and body mass indices of groups did not differ significantly ( table 1 ) .
comparison of demographic characteristics and biochemical parameters of study groups bmi : body mass index ; dbp : diastolic blood pressure ; fbg : fasting blood glucose ; hdl - c : high - density lipoprotein cholesterol ; hs - crp : high - sensitivity c - reactive protein ; ldl - c : low - density lipoprotein cholesterol ; sbp : systolic blood pressure ; tg : triglyceride .
hs - crp levels of cid patients were significantly higher ( 4.8 [ 1.812.0 ] vs 1.3 [ 0.82.2 ] ; p<0.001 ) ( table 1 ) .
tg / hdl - c levels of the patients with cid were significantly higher when compared to control group ( 2.5 [ 2.22.8 ] vs 2.3 [ 2.12.5 ] ; p=0.03 ) ( figure 1 ) .
lvedd , lvesd , ejection fraction ( ef ) , thickness of ivs , and pd were similar between groups ( table 2 ) .
e / e ratios of patients with cid were lower when compared to control group with a p - value close to level of significance ( 3.80.9 vs 4.21.1 ; p=0.06 ) ( table 2 ) .
comparison of echocardiographic parameters and fmd values of study groups a : atrial ; dt : deceleration time ; e : early ; ef : ejection fraction , fmd : flow - mediated dilatation ; ivrt : isovolumic relaxation time ; ivs : interventricular septum ; lvedd : left ventricular end - diastolic diameter ; lvesd : left ventricular end - systolic diameter ; ppd : posterior wall .
fmd values of the patients with cid were significantly lower when compared to cid patients ( 5.2 [ 4.26.3 ] vs 6.7 [ 6.39.7 ] ; p<0.001 ) ( figure 2 ) .
in addition , negative correlation was detected between elevated tg / hdl - c ratio and fmd values ( figure 3 ) .
correlation curve for comparison between tg / hdl - c ratio and fmd values of study population .
median age of the patient ( cid ) and control group was 37 ( 3147 ) and 39 ( 3741 ) years , respectively , without any intergroup difference .
systolic and diastolic blood pressure and body mass indices of groups did not differ significantly ( table 1 ) .
comparison of demographic characteristics and biochemical parameters of study groups bmi : body mass index ; dbp : diastolic blood pressure ; fbg : fasting blood glucose ; hdl - c : high - density lipoprotein cholesterol ; hs - crp : high - sensitivity c - reactive protein ; ldl - c : low - density lipoprotein cholesterol ; sbp : systolic blood pressure ; tg : triglyceride .
hs - crp levels of cid patients were significantly higher ( 4.8 [ 1.812.0 ] vs 1.3 [ 0.82.2 ] ; p<0.001 ) ( table 1 ) .
tg / hdl - c levels of the patients with cid were significantly higher when compared to control group ( 2.5 [ 2.22.8 ] vs 2.3 [ 2.12.5 ] ; p=0.03 ) ( figure 1 ) .
lvedd , lvesd , ejection fraction ( ef ) , thickness of ivs , and pd were similar between groups ( table 2 ) .
e / e ratios of patients with cid were lower when compared to control group with a p - value close to level of significance ( 3.80.9 vs 4.21.1 ; p=0.06 ) ( table 2 ) .
comparison of echocardiographic parameters and fmd values of study groups a : atrial ; dt : deceleration time ; e : early ; ef : ejection fraction , fmd : flow - mediated dilatation ; ivrt : isovolumic relaxation time ; ivs : interventricular septum ; lvedd : left ventricular end - diastolic diameter ; lvesd : left ventricular end - systolic diameter ; ppd : posterior wall .
fmd values of the patients with cid were significantly lower when compared to cid patients ( 5.2 [ 4.26.3 ] vs 6.7 [ 6.39.7 ] ; p<0.001 ) ( figure 2 ) . in addition
, negative correlation was detected between elevated tg / hdl - c ratio and fmd values ( figure 3 ) .
correlation curve for comparison between tg / hdl - c ratio and fmd values of study population .
studies have demonstrated that inflammation plays a fundamental role at all stages of atherosclerosis from beginning through development of thrombotic complications [ 2 , 3 ] .
fmf is an autoinflammatory disease caused by mutation of fmf gene , and is characterized by periodic hyperfebrile episodes and polyserositis .
asymptomatic periods exist between episodes of fmf , but during these intervals subclinical inflammation continues and it has been established that in cases of chronic inflammatory disease such as fmf , risk of atherosclerosis remains [ 15 , 16 ] .
anxylosing spondylitis is a prototype of spondyloarthropathies , and in these patients 1.52-fold increase in mortality rates is seen due to cardiovascular complications compared to overall population .
as is the case with other chronic inflammatory rheumatologic diseases , accelerated atherosclerotic processes are responsible for increase in cardiovascular mortality .
inflammation plays a fundamental role in accelerated atherogenesis in this patient group [ 17 , 18 , 19 , 20 , 21 ] . in spondyloarthropathic patients with chronic inflammatory polyarthritis
, a significant correlation was observed between levels of c - reactive protein , erythrocyte sedimentation rate , and presence of endothelial dysfunction .
endothelial dysfunction was determined with a noninvasive method , while response of brachial artery diameter to reactive hyperemia was measured with the aid of high - resolution us device .
reactive hyperemia induces increase in blood flow , wall strain , nitric oxide release , and fmd .
fmd can be measured as an index of vasomotor function [ 22 , 23 ] .
demonstrated presence of endothelial dysfunction in patients with as based on significant decrease in fmd values compared to healthy population , and sar et al .
found significantly lower fmd values in as patients when compared to healthy population . in the present study , fmd values in a group of cid patients consisting of cases of as , and fmf ,
were compared to those of healthy population and , similar to previous studies , significantly lower fmd levels were detected in the cid patient group .
fmd indirectly demonstrates endothelial dysfunction of coronary arteries , and tg / hdl - c ratio is an easily calculated and reproducible predictor of atherosclerosis in daily practice .
close relationship between tg / hdl - c ratio and insulin resistance has been noted .
in addition , tg / hdl - c has been demonstrated to be a strong predictor independent of important prognostic variables , including total mortality , incidence of coronary artery disease , cardiovascular mortality , age , cigarette use , hypertension , and diabetes [ 31 , 32 , 33 , 34 ] .
detected significantly higher tg / hdl - c ratio in patients with fmf versus healthy population .
however , the correlation between tg / hdl - c ratio and endothelial dysfunction in cid cases has not been fully clarified . in this study ,
correlation between tg / hdl - c ratio , defined as an atherogenic index , and fmd was investigated . in parallel with findings in previous studies ,
this study found tg / hdl - c ratio in patients with cid was significantly higher when compared to control group .
the findings of this study indicate that in patients with cid , increased tg / hdl - c ratio is correlated with decreased fmd value , an indicator of endothelial dysfunction that is precursor of atherosclerosis .
thus , higher tg / hdl - c ratio was found to be associated with presence of endothelial dysfunction and atherogenesis . in conclusion
, this study determined that tg / hdl - c ratio in cid patients may be used as an easily evaluated , reliable predictor of atherosclerosis .
Output:
| objective : the term chronic inflammatory disease ( cid ) refers to a category of inflammatory diseases that includes ankylosing spondylitis ( as ) and familial mediterranean fever ( fmf ) .
the incidence of adverse cardiovascular events is greater among patients with cid , though they may not have conventional atherosclerotic risk factors .
endothelial dysfunction is one of the underlying fundamental mechanisms that trigger development of atherosclerotic alterations in arteries , and flow - mediated dilatation ( fmd ) is a noninvasive method to determine endothelial dysfunction .
recent studies have shown a relationship between high triglyceride high - density lipoprotein cholesterol ( tg / hdl - c ) ratio and coronary atherosclerosis .
many studies have demonstrated that patients with cid have lower fmd values compared to healthy population , indicating endothelial dysfunction
. however tg / hdl ratio and its relationship to fmd in patients with cid has not been investigated .
the present study investigated whether tg / hdl ratio in cid patients differs from that of healthy population , and its relationship to fmd in patients with cid.methods:a total of 58 patients with cid and a group of 58 healthy volunteer individuals were enrolled in the study .
fmd measurements were taken with high resolution ultrasound ( us ) , and tg / hdl ratios were calculated.results:patients with cid had significantly higher tg / hdl - c ratio ( 2.5 [ 2.22.8 ] vs 2.3 [ 2.12.5 ] ; p=0.03 ) and lower fmd values ( 5.2 [ 4.26.3 ] vs 6.7 [ 6.39.7 ] ; p<0.001 ) , compared to healthy group , and a negative correlation was found between fmd levels and tg / hdl ratio of the study population.conclusion:higher tg / hdl ratio and lower fmd values found in cid patients may reflect increased atherosclerotic risk . |
PubmedSumm118775 | ***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: pine et al have used recently developed measuring tools1 to demonstrate that the presence of surface deposits on prosthetic eyes is associated with less conjunctival inflammation and less severe mucoid discharge in anophthalmic sockets.2 however , the causal direction of these associations was not established in this study . furthermore , there appears to be no literature describing deposit buildup on prosthetic eyes , even though extensive literature describes deposit buildup on contact lenses .
prosthetic eyes are somewhat analogous to contact lenses , but are made from different materials and worn for very different reasons .
both devices come into contact with the conjunctiva , share a similar eyelid action , are bathed in the same ocular fluids , and accumulate surface deposits . because of these similarities
for example , the composition of deposits on contact lenses is likely to be similar to deposits on prosthetic eyes .
contact lens deposits include tear proteins , lipids ( lipid deposit buildup may be both on the surface and inside the lens matrix3,4 ) , mucin , and contaminants , such as skin lipids , dirt , micro - organisms , and metallic and nonmetallic debris.5 the aims of this investigation were : to describe the formation of surface deposits on prosthetic eyes over time ; to investigate rates of deposit buildup on prostheses with different standards of polish ; and to understand the cause of the reported associations between deposits , conjunctival inflammation , and severity of mucoid discharge.1
forty - three unilateral prosthetic eye wearers were entered into the study after they completed a questionnaire and agreed to participate in prosthetic eye research which had prior approval from the university of auckland human participants ethics committee and the multi - region ethics committee of the new zealand ministry of health .
participants were excluded from the study if they were aged younger than 18 years , had ocular health issues , or had not worn a prosthetic eye for at least 6 months .
a staining solution was made by dispersing 5 g of plaque disclosing gel ( a mix of mainly ethyl alcohol , food red 105 , and water ; gc corporation , tokyo , japan ) in 30 ml of 0.85% saline solution.1 the participants prostheses were submerged in the solution at 20c ( 68f ) for a period of 2 minutes . after removing and blotting with tissue paper , the prosthetic eyes were photographed front and back against a black background which included a standard gray scale and a color scale to ensure the consistency of photographic settings throughout the study .
standardized camera settings were used.2 photographs of the stained prostheses were coded to deidentify the participant but to allow tracking .
each photograph was copied onto the center of a microsoft powerpoint ( microsoft corporation , redmond , wa ) slide which contained a previously developed 010 photographic grading scale by which the extent and intensity of deposit buildup could be measured.1 separate anterior surface and posterior surface deposit scales allowed assessment of the severity of deposit buildup according to the extent and intensity of the stained deposits .
the graders were the authors ( an experienced ophthalmologist , optometrist , and ocular prosthetist ) who used interpolated grades to the nearest 0.1 between 0 and 10 when assessing the deposits .
the final grade for the stained deposits on each prosthetic eye was the average of the three graders anterior surface and posterior surface scores .
firstly , the prosthesis was trimmed and the surfaces ground all over with a fine ( 120 grit ) arbor band .
secondly , diatomaceous earth was applied to the surfaces with a wet calico polishing mop and/or a felt cone to remove the marks left by the arbor band .
thirdly , polishing compound for plastics final polish ( bego , lincoln , ri6 ) was applied with a dry calico polishing mop to achieve the normal polish grade .
the bego product is no longer in production but is similar to other commercially available denture polishing compounds .
fourthly , an optical quality contact lens polishing standard was obtained using aluminum oxide paste applied with a foam polyurethane rotating cone .
twenty - three of the 43 participants enrolled in the study had their prostheses finished to a normal polishing standard before return to the socket where they were worn without removing and cleaning for 2 weeks . at the end of the 2-week period ,
the prostheses were removed and their surface deposits were graded according to the method for measuring surface deposits on prosthetic eyes described above .
the prostheses were then cleaned and polished to an optical quality contact lens standard before being returned to the participants and worn continuously for a further 2 weeks . at this point , they were removed and their surface deposits were graded as before .
concordance correlation7 and paired t - tests were used to investigate differences after 2 weeks of continuous wear between the grade of deposit buildup on prosthetic eyes polished to normal standard and to optical quality contact lens standard .
two of the 43 participants were chosen because their prostheses had not been removed and cleaned for 12 months .
their prostheses were removed and the surface deposits were measured according to the method for measuring surface deposits on prosthetic eyes described above .
the stained deposits were removed by wiping them firmly with a paper towel wetted with cold water before being returned to the participants for continued wear without removing or cleaning .
this measuring process was repeated eight more times at decreasing intervals ranging from one month to one day . the extent and intensity of the stained deposits at each interval
was plotted as a function of time , and regression analysis was used to describe the results further .
the final 18 of the 43 participants were requested to not remove or clean their prostheses for at least 24 hours . after this time , their prostheses were removed and gently blotted dry with tissue paper before being placed in a goniometer .
distilled water droplets were applied to the least convex area that could be found on each prosthesis ( usually just on or above the superior limbus ) .
wetting angles were assessed and the average of right and left angles made by each droplet of water was calculated for each prosthetic eye .
the prostheses were wiped clean of deposits with a wetted paper towel and the wetting angles were measured again . they were measured a third time after the prostheses were polished to a normal standard ( as described earlier in the methods used for polishing prosthetic eyes ) , and a fourth time after the prostheses were polished to an optical quality contact lens standard .
the prosthetic eyes were then returned to the participants and ten of them wore their prostheses for 10 minutes before returning to have the wetting angles on their prosthetic eyes measured a fifth time .
a staining solution was made by dispersing 5 g of plaque disclosing gel ( a mix of mainly ethyl alcohol , food red 105 , and water ; gc corporation , tokyo , japan ) in 30 ml of 0.85% saline solution.1 the participants prostheses were submerged in the solution at 20c ( 68f ) for a period of 2 minutes . after removing and blotting with tissue paper , the prosthetic eyes were photographed front and back against a black background which included a standard gray scale and a color scale to ensure the consistency of photographic settings throughout the study .
standardized camera settings were used.2 photographs of the stained prostheses were coded to deidentify the participant but to allow tracking .
each photograph was copied onto the center of a microsoft powerpoint ( microsoft corporation , redmond , wa ) slide which contained a previously developed 010 photographic grading scale by which the extent and intensity of deposit buildup could be measured.1 separate anterior surface and posterior surface deposit scales allowed assessment of the severity of deposit buildup according to the extent and intensity of the stained deposits .
the graders were the authors ( an experienced ophthalmologist , optometrist , and ocular prosthetist ) who used interpolated grades to the nearest 0.1 between 0 and 10 when assessing the deposits .
the final grade for the stained deposits on each prosthetic eye was the average of the three graders anterior surface and posterior surface scores .
firstly , the prosthesis was trimmed and the surfaces ground all over with a fine ( 120 grit ) arbor band .
secondly , diatomaceous earth was applied to the surfaces with a wet calico polishing mop and/or a felt cone to remove the marks left by the arbor band .
thirdly , polishing compound for plastics final polish ( bego , lincoln , ri6 ) was applied with a dry calico polishing mop to achieve the normal polish grade .
the bego product is no longer in production but is similar to other commercially available denture polishing compounds .
fourthly , an optical quality contact lens polishing standard was obtained using aluminum oxide paste applied with a foam polyurethane rotating cone .
twenty - three of the 43 participants enrolled in the study had their prostheses finished to a normal polishing standard before return to the socket where they were worn without removing and cleaning for 2 weeks . at the end of the 2-week period ,
the prostheses were removed and their surface deposits were graded according to the method for measuring surface deposits on prosthetic eyes described above .
the prostheses were then cleaned and polished to an optical quality contact lens standard before being returned to the participants and worn continuously for a further 2 weeks . at this point , they were removed and their surface deposits were graded as before .
concordance correlation7 and paired t - tests were used to investigate differences after 2 weeks of continuous wear between the grade of deposit buildup on prosthetic eyes polished to normal standard and to optical quality contact lens standard .
two of the 43 participants were chosen because their prostheses had not been removed and cleaned for 12 months .
their prostheses were removed and the surface deposits were measured according to the method for measuring surface deposits on prosthetic eyes described above .
the stained deposits were removed by wiping them firmly with a paper towel wetted with cold water before being returned to the participants for continued wear without removing or cleaning .
this measuring process was repeated eight more times at decreasing intervals ranging from one month to one day . the extent and intensity of the stained deposits at each interval
was plotted as a function of time , and regression analysis was used to describe the results further .
the final 18 of the 43 participants were requested to not remove or clean their prostheses for at least 24 hours . after this time , their prostheses were removed and gently blotted dry with tissue paper before being placed in a goniometer .
distilled water droplets were applied to the least convex area that could be found on each prosthesis ( usually just on or above the superior limbus ) .
wetting angles were assessed and the average of right and left angles made by each droplet of water was calculated for each prosthetic eye .
the prostheses were wiped clean of deposits with a wetted paper towel and the wetting angles were measured again . they were measured a third time after the prostheses were polished to a normal standard ( as described earlier in the methods used for polishing prosthetic eyes ) , and a fourth time after the prostheses were polished to an optical quality contact lens standard .
the prosthetic eyes were then returned to the participants and ten of them wore their prostheses for 10 minutes before returning to have the wetting angles on their prosthetic eyes measured a fifth time .
the rate of deposit buildup was greater on normally polished prostheses than on prostheses polished to optical quality contact lens standard .
after 2 weeks of continuous wear , the normally polished prostheses had significantly more deposits ( mean 3.06 1.91 ) than prostheses polished to optical quality contact lens standard ( mean 2.26 2.00 , paired - samples t - test , mean difference 0.81 1.40 , 95% confidence intervals 1.48 to 0.13 , p = 0.02 ) .
regression analysis results ( coefficient of determination r = 0.98 , residual standard deviation = 0.4 , p < 0.0001 ) are shown in figure 3 .
the photographic series in figure 4 illustrates the rate of buildup of deposits on the surface of the prosthetic eye worn by participant 2 in figure 2 .
a notable characteristic of deposit formation indicated by the photographs is that the interpalpebral zone ( observed without magnification ) remained clear of stained deposits for considerable periods of continuous wear .
however , it was observed that deposits could encroach onto this space after prolonged periods .
the wetting angles of prosthetic eyes when first removed from the socket increased significantly when the eyes were wiped clean with a paper towel wetted with cold water ( p < 0.0001 ) and when they were polished to a normal standard ( p < 0.0001 ) .
the increased wetting angles indicated that the wettability of prosthetic eye surfaces was reduced when deposits were removed and was reduced further still when the prostheses were polished to a normal standard .
however , the wetting angles of prosthetic eyes when first removed from the socket were not significantly different to the wetting angles of prostheses freshly polished to an optical quality contact lens standard ( p = 0.117 ) or to wetting angles 10 minutes after the prosthetic eyes were placed back in their sockets ( p = 1.0 ; table 1 and figure 6 ) .
these wetting angle measurements indicate that the wettability of the prosthetic eye surfaces was the same for prostheses worn continuously for at least 24 hours , for prostheses polished to an optical quality contact lens standard before wear , and for freshly polished prostheses after 10 minutes in the socket .
the rate of deposit buildup was greater on normally polished prostheses than on prostheses polished to optical quality contact lens standard .
after 2 weeks of continuous wear , the normally polished prostheses had significantly more deposits ( mean 3.06 1.91 ) than prostheses polished to optical quality contact lens standard ( mean 2.26 2.00 , paired - samples t - test , mean difference 0.81 1.40 , 95% confidence intervals 1.48 to 0.13 , p = 0.02 ) .
regression analysis results ( coefficient of determination r = 0.98 , residual standard deviation = 0.4 , p < 0.0001 ) are shown in figure 3 .
the photographic series in figure 4 illustrates the rate of buildup of deposits on the surface of the prosthetic eye worn by participant 2 in figure 2 .
a notable characteristic of deposit formation indicated by the photographs is that the interpalpebral zone ( observed without magnification ) remained clear of stained deposits for considerable periods of continuous wear .
however , it was observed that deposits could encroach onto this space after prolonged periods .
the wetting angles of prosthetic eyes when first removed from the socket increased significantly when the eyes were wiped clean with a paper towel wetted with cold water ( p < 0.0001 ) and when they were polished to a normal standard ( p < 0.0001 ) .
the increased wetting angles indicated that the wettability of prosthetic eye surfaces was reduced when deposits were removed and was reduced further still when the prostheses were polished to a normal standard .
however , the wetting angles of prosthetic eyes when first removed from the socket were not significantly different to the wetting angles of prostheses freshly polished to an optical quality contact lens standard ( p = 0.117 ) or to wetting angles 10 minutes after the prosthetic eyes were placed back in their sockets ( p = 1.0 ; table 1 and figure 6 ) .
these wetting angle measurements indicate that the wettability of the prosthetic eye surfaces was the same for prostheses worn continuously for at least 24 hours , for prostheses polished to an optical quality contact lens standard before wear , and for freshly polished prostheses after 10 minutes in the socket .
before the introduction of hydrogel ( soft ) and rigid gas permeable lenses , almost all contact lenses were made from poly - methyl methacrylate ( pmma ) , which is the same material used for manufacturing prosthetic eyes .
deposits on pmma contact lenses are similar in form to deposits on soft lenses,8 but no comparisons between deposits on pmma lenses and pmma prosthetic eyes are available .
fowler et al8 used scanning electron microscopy to investigate deposits on the anterior surfaces of pmma contact lenses .
they found that deposits on pmma lenses were readily removed with a single cleaning and that pmma lenses attracted fewer deposits than soft lenses .
the layered coatings , films , or plaques of tear protein deposits described by franklin et al9 appear to be similar to the most prevalent type of deposits on prosthetic eyes .
they mainly occupy the surfaces that are in continuous contact with the conjunctiva and can be seen in figure 7 , which depicts dry stained deposits on the temporal limbus of a left prosthetic eye worn continuously for 3 months ( magnification 400 ) .
two distinct zones of surface deposit buildup on prosthetic eyes were observed in this study .
the first was the interpalpebral zone , where deposits are exposed to air and the action of the eyelids , and the second was the retropalpebral zone , where deposits are in continuous contact with the conjunctiva .
these areas are clearly shown in figure 1 , prosthesis 2 . while the interpalpebral zone appeared to be clear of deposits , microscopic analysis was not used in this study .
if deposits are present in the interpalpebral zone , they are likely to be the same or similar to the deposits on contact lenses described by fowler et al8 and franklin et al.9 issues such as inefficient or incomplete blinking are likely to influence deposit buildup in the interpalpebral zone , but not on other areas of the prosthesis .
the normal polishing technique described in this study is the usual standard of finish for dentures and most prosthetic eyes ( at least in new zealand ) , while the optical quality contact lens polish is the technique commonly used for polishing hard contact lenses .
optical quality contact lens polish has been recommended for prosthetic eye polishing by legrand.10 the finding that prosthetic eyes polished to an optical quality contact lens standard accumulated deposits at slower rates than normally polished prosthetic eyes suggests that adherence of deposits depends on the relationship between surface matrix fineness and the size of protein molecules , and that the surface matrix of normally polished prosthetic eye surfaces enables protein molecules to adhere more readily than finer polishes .
for example , franklin et al reported that one of the reasons that deposits take longer to build up on rigid gas permeable lenses than on hydrogel lenses is that rigid gas permeable polymers have lower matrix porosity.3 surface wettability is another factor that influences deposition on contact lenses , with increasing wettability having been shown to decrease deposition.11 a goniometer was used in this study for measuring wetting angles on prosthetic eyes .
wetting angle ( or contact angle ) analysis has become a widely accepted method by which to infer the wetting characteristics of contact lenses .
it involves measuring the angle between a liquid and the lens surface at the three - phase boundary where a liquid , gas , and solid intersect.12 the findings that prosthetic eyes polished to an optical quality contact lens standard show more wettability than those polished to a normal standard , and that higher polished surfaces accumulate deposits at a slower rate , might be particularly important for the surface finish of the interpalpebral zone of the prosthesis .
this is the zone where wetting and drying cycles occur and where the cleansing action of tears takes place .
the interpalpebral zone needs to be as free from deposits as possible to avoid conjunctival battering during blinking .
as the eyelids slide over the interpalpebral zone of a prosthetic eye containing deposits and debris , the area most likely to receive this battering is marx s line13 which has been shown to develop epitheliopathy in contact lens patients with dry eye symptoms.14 clearly , deposits left in the interpalpebral zone of prosthetic eyes are not likely to be beneficial to wearing comfort and , consequently , it is recommended that prostheses polished to an optical quality contact lens standard be the minimum standard for prosthetic eye finishes .
an optical quality contact lens standard of finish may also facilitate the lubricating function of tears in the retropalpebral zone when the prosthesis is first inserted into the socket and before the layered coatings , films , or plaques of tear protein deposits become established .
the finding that wetting angles decreased ( and wettability increased ) significantly when deposits were present in the retropalpebral zone may be the reason why surface deposits are associated with less severe conjunctival inflammation in anophthalmic sockets1 and that more frequent cleaning of prosthetic eyes ( deposit removal ) is associated with more severe discharge.15 by increasing surface wettability , the deposits may improve the ability of socket fluids to lubricate the prosthesis .
if mucins are present in prosthetic eye deposits , as they are in contact lens deposits,16 components of glycoproteins such as the surfactant glycocalyx17 may also facilitate the lubricating function .
the consequence of these properties of deposits would be that less frictional irritation of the conjunctiva occurs when deposits are present .
the finding that wetting angles of prosthetic eye surfaces decreased after only ten minutes of wear ( suggesting the presence of protein deposits ) is consistent with a number of observations reported in the contact lens literature.16,1820 limitations of the study include the short period of the 2-week experiment with different surface polishes ( figure 1 ) because this did not reveal how long the difference in deposit buildup rates for the two polishing standards might last .
the investigation concerning the rate of deposit buildup on prosthetic eyes worn by two participants had limitations because of the small sample size .
the reason for this small number was the invasive nature of the experiment coupled with the shortage of available participants who cleaned their prostheses less frequently than yearly .
both devices come into contact with the conjunctiva , share a similar eyelid action , are bathed in the same ocular fluids , and accumulate surface deposits .
because of these similarities , relevant information from contact lens investigations has been included in this study .
the first is the interpalpebral zone where deposits are exposed to the air and the action of the eyelids , and the second is the retropalpebral zone where deposits are in continuous contact with the conjunctiva .
we recommend that an optical quality contact lens standard of finish ( shown to have better wettability and a slower rate of deposit buildup ) be the minimum standard of finish for prosthetic eyes .
this standard may be important for the interpalpebral surface , where it assists the smooth action of the lids over the interpalpebral zone of the prosthesis and the cleansing action of tears .
when deposits were removed by cleaning , surface wettability decreased significantly , suggesting that the presence of deposits in the retropalpebral zone improves the lubricating properties of socket fluids which , in turn , may result in less frictional irritation of the conjunctiva when the prosthesis moves .
this finding provides evidence for a causal link between the presence of deposits and less conjunctival inflammation and discharge reported by pine et al.2
Output:
| backgroundthe aim of this study was to investigate deposit buildup on prosthetic eyes and the implications for conjunctival inflammation and discharge.methodsforty-three prosthetic eye wearers participated in the study .
twenty - three had their prostheses polished normally before being worn continuously for 2 weeks .
after this time , surface deposits were stained , photographed , and graded .
the prostheses were then repolished to optical quality contact lens standard and worn for a further 2 weeks , when the deposits were again stained , photographed , and graded .
two participants had deposits on their prostheses stained , photographed , and graded on nine occasions at decreasing intervals ranging from 1 year to 1 day .
eighteen participants had the wetting angles on their prostheses measured with a goniometer before and after cleaning , after polishing normally , after polishing to optical quality contact lens standard , and after 10 minutes of wearing their optical quality contact lens polished prostheses .
concordance correlation , multiple regression , and paired t - tests were used for the statistical analysis.resultsmore surface deposits accumulated on prostheses polished normally than on those polished to an optical quality contact lens standard after 2 weeks of wear .
the interpalpebral zone of most prostheses ( observed without magnification ) appeared to be clear of deposits .
removal of deposits significantly decreased surface wettability , but wettability returned after 10 minutes of wear .
optical quality contact lens polishing produced more wettable surfaces and a slower rate of deposit accumulation than normal polishing.conclusionwe recommend that an optical quality contact lens standard be the minimum standard of finish for prosthetic eyes .
this standard may assist the smooth action of the lids over the interpalpebral zone of the prosthesis and the cleansing action of tears .
the presence of deposits in the retropalpebral zone may improve the lubricating properties of socket fluids which , in turn , may result in less frictional irritation of the conjunctiva and less mucoid discharge . |
PubmedSumm118776 | ***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:
| in our recently published article , we investigated the behavioral addiction model of obsessive compulsive disorder ( ocd ) , by assessing three core dimensions of addiction in patients with ocd healthy participants .
similar to the common findings in addiction , ocd patients demonstrated increased impulsivity , risky decision - making , and biased probabilistic reasoning compared to healthy controls .
thus , we concluded that these results support the conceptualization of ocd as a disorder of behavioral addiction .
here , we answer to abramovitch and mckay ( 2016 ) commentary on our paper and we support our conclusions by explaining how cognitive impulsivity is also a typical feature of addiction and how our results on decision - making and probabilistic reasoning tasks reflect cognitive impulsivity facets that are consistently replicated in ocd and addiction . |
PubmedSumm118777 | ***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: attendance at emergency departments and unplanned hospital readmissions are common for frail older patients after discharge from the hospital.1 patients with chronic illnesses frequently perceived powerlessness in managing their disease after hospital discharge , and they are prompted to seek hospital readmission immediately upon symptom exacerbation.2 unplanned readmission is usually defined as readmission to the hospital within 28 days postdischarge.3,4 in hong kong , it was estimated that the unplanned readmission rate was 16.7% in the general population,3 and more than 20% in the elderly subpopulation.4 the hong kong hospital authority has developed a 14-variable predictive model
the hospital administration risk reduction programme for the elderly ( harrpe ) to predict the risk of emergency medical admissions in 28 days after an index hospital visit among elderly patients aged 65 years or above.4 an elderly patient with a harrpe score of 0.2058 was considered as having a high risk of emergency admission . according to the unpublished statistical record from the medical unit of six hospitals under the operation of the hospital authority in 2009 ,
the average length of stay for patients with a harrpe score of 0.4 is 23 days , which is much higher than the corresponding figure of 5.9 days in the hong kong general population.3 currently , patients are provided with a community nursing service after hospital discharge in hong kong ; it is , therefore , essential to develop effective intervention programs to help prevent unplanned readmission among those elderly patients who are at high risk .
the concept of virtual ward is a new model of care that was pioneered in 2004 in the uk.5,6 the aim is to provide clients at high risk of hospital readmission with intensive multidisciplinary and coordinated extensive services so as to facilitate their receiving the necessary care in their own homes , thereby reducing hospital readmissions .
since the concept of virtual ward employs the systems , staffing , and daily routine of a hospital ward to deliver care to clients in their home settings,6 the virtual ward does not have a physical ward building .
patients admitted to the virtual ward are visited by community nurses for the delivery of routine nursing care normally provided in the hospital , such as measuring their blood sugar levels , administering insulin , and performing wound dressing , at their homes .
physicians and other allied health care professionals may also be involved , depending on the patient s health condition.5 evidence supporting the effectiveness of the virtual ward service was reported in the literature .
the hospital - at - home care resulted in a reduction in the length of hospitalization compared to inpatient care in a systematic review,7 and it was shown to have a better effect in reducing emergency visits in comparison with usual home care visits in patients with acute or complex conditions requiring care for an anticipated 510 days.8 a 7-year longitudinal study on a large cohort of patients receiving acute hospital services at home reported low rates of unexpected mortality ( 0.15% ) and unplanned returns to hospital ( 4.2%).9 previous studies also supported that patient satisfaction was greater with virtual ward care,6,8 and potential improvements in quality of life ( qol ) , depression , and nutritional status in elderly patients with chronic heart failure have also been reported.10 the greater satisfaction might be attributed to a more personal style of care and a feeling that staying at home was therapeutic.11 the purpose of this study is to evaluate the effectiveness of the virtual ward service as compared to community nursing care on health services utilization and the qol of patients who are at extremely high risk for emergency readmission .
the study was conducted from march 2012january 2013 at the kowloon and new territories west clusters under the catchment areas of community nursing services of four regional hospitals of the hong kong hospital authority .
subjects were eligible if they had been discharged from hospital , had a harrpe score 0.4 , or had a major functional disability as clinically indicated , and were being supported by home carers who were living with the patients .
the study was approved by the institutional review board of kowloon east cluster , kowloon central cluster , kowloon west cluster , and new territories west cluster of hong kong hospital authority .
a total of 40 pairs of patients and their carers recruiting from three of the four participating hospitals were assigned to the intervention group , while another 40 matched patient carer dyads recruiting from the remaining hospital were assigned to the control group .
carer dyads in the control group ; these included : 1 ) disease type of the patient ; 2 ) frailty level of the patient as measured by the validated clinical frailty index;12,13 3 ) sex of the patient ; 4 ) age of the patient ( 5 years ) ; and 5 ) the carer s relationship with the patient ( maid / spouse / children / relatives ) .
this sample size is considered to be adequate for estimating a between - group difference for the pilot study.14 eligible patients were admitted to the three selected hospitals delivering the virtual ward service and their carers were invited to participate in the study .
the screening of the subjects was performed by virtual ward nurses at the participating hospitals .
the research assistant of the project then conducted the baseline assessment to both the patient and the carer in the intervention group at home before the implementation of the service by the virtual ward team .
carer dyad in the intervention group , a matched control dyad was then selected from the fourth hospital by using the above five matching criteria by the nurses in the hospital .
the research assistant then administered the baseline assessment to the consented matched control at their homes .
participants in the intervention group received the virtual ward service while those in the control group received the usual community nursing service provided to patients discharged from hospitals in hong kong . at 3 months or discharge from the virtual ward ( whichever is earlier ) , a follow - up survey using a standardized questionnaire via face - to - face interviews was administered to both the patients and their carers .
three measures that are related to services utilization of the emergency department were reported in the current study : length of the hospitalization via emergency department ; number of unplanned emergency hospital admissions ; and number of emergency attendances in the past 90 days .
the patient s qol was measured by the locally validated instrument , namely , the chinese version modified quality - of - life concerns in the end of life questionnaire ( mqolc - e).15,16 the scale consists of 23 items measuring the six dimensions of : 1 ) negative emotions ; 2 ) physical discomfort ; 3 ) value of life ; 4 ) existential distress ; 5 ) care and support ; and 6 ) food - related concerns , on a 4-point likert scale , and the scores ranged from 1 , the least satisfaction to 4 , the most satisfaction toward the condition , with higher scores indicating a better qol .
modifications were made to two items on the care and support concern subscale of the instrument regarding perception of the care the patient received .
in particular , the two items originally asking the respondents to rate the care they received in hospital have been changed to the care they are currently receiving ( ie , the virtual ward service for subjects in the intervention group and the usual community nursing care in the control group ) .
aggregate scores were created for the overall score and each of the six dimensions of the scale by averaging the corresponding items .
cronbach s alpha value for the overall score was 0.835 , and those for the six dimensions ranged from 0.791 for value of life to 0.879 for negative emotions in the current sample .
the patients in the intervention group received the service provided by the virtual ward health care team that consisted of nurses and physicians in the respective cluster .
the virtual ward service focused on the provision of hospital - level care to patients and health care supports to their carers at their homes .
patients were then individually assigned to a virtual ward nurse ( primary nurse ) ; and the virtual ward nurse conducted the first home visit as soon as possible within 48 hours after the patient was discharged from the hospital .
the virtual ward physician might conduct a physician home visit within the first week after the patient was discharged .
based on the health assessment results , the virtual ward nurses planned the schedule of home visits which could range from daily to once every 2 weeks . during the home visits ,
the virtual ward nurses provided direct patient care and health education , such as monitoring and handling symptom exacerbation , to the patients and their carers .
the virtual ward nurses also provided psychosocial supports to both the patients and their carers .
the schedule of home visits was individualized , and each patient was visited about four times per week on average during the study . in addition , an extended service beyond office hours and a hotline consultation service were also provided for the patients and their carers by the virtual ward teams .
this additional service aims to enable the patients to have fast - track medical consultations by establishing various fast - track services , such as fast - track clinic , direct clinical admission , and enhanced nonemergency ambulance transportation service support .
the frequency of calls to the hotline was reported to be at most three times in a week during the study .
patients in the control group received community nursing service , referred by the physician in charge , that was based on the patients specific nursing care needs postdischarge ; this included wound dressing , catheterization , and health education for the patients self - care of their chronic diseases .
descriptive statistics , including frequencies and percentages for categorical data and means and standard deviations for continuous data , were calculated for the baseline data of the sample .
normality of data was checked by using z - tests for skewness and kurtosis.17 paired t - tests for normal data and wilcoxon signed - rank tests for nonnormal data were used to compare the differences in the changes of the outcome variables between the two groups using all available data .
we also conducted a sensitivity analysis for hospital service utilization by excluding those patients who had died during the study .
all statistical tests were two - sided , and a p - value < 0.05 was considered statistically significant .
all the analyses were performed by using spss version 20.0 ( ibm corporation , armonk , ny , usa ) .
the study was conducted from march 2012january 2013 at the kowloon and new territories west clusters under the catchment areas of community nursing services of four regional hospitals of the hong kong hospital authority .
subjects were eligible if they had been discharged from hospital , had a harrpe score 0.4 , or had a major functional disability as clinically indicated , and were being supported by home carers who were living with the patients .
the study was approved by the institutional review board of kowloon east cluster , kowloon central cluster , kowloon west cluster , and new territories west cluster of hong kong hospital authority .
a total of 40 pairs of patients and their carers recruiting from three of the four participating hospitals were assigned to the intervention group , while another 40 matched patient carer dyads recruiting from the remaining hospital were assigned to the control group .
carer dyads in the control group ; these included : 1 ) disease type of the patient ; 2 ) frailty level of the patient as measured by the validated clinical frailty index;12,13 3 ) sex of the patient ; 4 ) age of the patient ( 5 years ) ; and 5 ) the carer s relationship with the patient ( maid / spouse / children / relatives ) .
this sample size is considered to be adequate for estimating a between - group difference for the pilot study.14 eligible patients were admitted to the three selected hospitals delivering the virtual ward service and their carers were invited to participate in the study .
the screening of the subjects was performed by virtual ward nurses at the participating hospitals .
the research assistant of the project then conducted the baseline assessment to both the patient and the carer in the intervention group at home before the implementation of the service by the virtual ward team .
carer dyad in the intervention group , a matched control dyad was then selected from the fourth hospital by using the above five matching criteria by the nurses in the hospital .
the research assistant then administered the baseline assessment to the consented matched control at their homes .
participants in the intervention group received the virtual ward service while those in the control group received the usual community nursing service provided to patients discharged from hospitals in hong kong . at 3 months or discharge from the virtual ward ( whichever is earlier ) , a follow - up survey using a standardized questionnaire via face - to - face interviews was administered to both the patients and their carers .
three measures that are related to services utilization of the emergency department were reported in the current study : length of the hospitalization via emergency department ; number of unplanned emergency hospital admissions ; and number of emergency attendances in the past 90 days .
the patient s qol was measured by the locally validated instrument , namely , the chinese version modified quality - of - life concerns in the end of life questionnaire ( mqolc - e).15,16 the scale consists of 23 items measuring the six dimensions of : 1 ) negative emotions ; 2 ) physical discomfort ; 3 ) value of life ; 4 ) existential distress ; 5 ) care and support ; and 6 ) food - related concerns , on a 4-point likert scale , and the scores ranged from 1 , the least satisfaction to 4 , the most satisfaction toward the condition , with higher scores indicating a better qol .
modifications were made to two items on the care and support concern subscale of the instrument regarding perception of the care the patient received .
in particular , the two items originally asking the respondents to rate the care they received in hospital have been changed to the care they are currently receiving ( ie , the virtual ward service for subjects in the intervention group and the usual community nursing care in the control group ) .
aggregate scores were created for the overall score and each of the six dimensions of the scale by averaging the corresponding items .
cronbach s alpha value for the overall score was 0.835 , and those for the six dimensions ranged from 0.791 for value of life to 0.879 for negative emotions in the current sample .
the patients in the intervention group received the service provided by the virtual ward health care team that consisted of nurses and physicians in the respective cluster .
the virtual ward service focused on the provision of hospital - level care to patients and health care supports to their carers at their homes .
patients were then individually assigned to a virtual ward nurse ( primary nurse ) ; and the virtual ward nurse conducted the first home visit as soon as possible within 48 hours after the patient was discharged from the hospital .
the virtual ward physician might conduct a physician home visit within the first week after the patient was discharged .
based on the health assessment results , the virtual ward nurses planned the schedule of home visits which could range from daily to once every 2 weeks . during the home visits , the virtual ward
nurses provided direct patient care and health education , such as monitoring and handling symptom exacerbation , to the patients and their carers .
the virtual ward nurses also provided psychosocial supports to both the patients and their carers .
the schedule of home visits was individualized , and each patient was visited about four times per week on average during the study . in addition , an extended service beyond office hours and a hotline consultation service were also provided for the patients and their carers by the virtual ward teams .
this additional service aims to enable the patients to have fast - track medical consultations by establishing various fast - track services , such as fast - track clinic , direct clinical admission , and enhanced nonemergency ambulance transportation service support .
the frequency of calls to the hotline was reported to be at most three times in a week during the study .
patients in the control group received community nursing service , referred by the physician in charge , that was based on the patients specific nursing care needs postdischarge ; this included wound dressing , catheterization , and health education for the patients self - care of their chronic diseases .
descriptive statistics , including frequencies and percentages for categorical data and means and standard deviations for continuous data , were calculated for the baseline data of the sample .
normality of data was checked by using z - tests for skewness and kurtosis.17 paired t - tests for normal data and wilcoxon signed - rank tests for nonnormal data were used to compare the differences in the changes of the outcome variables between the two groups using all available data .
we also conducted a sensitivity analysis for hospital service utilization by excluding those patients who had died during the study .
all statistical tests were two - sided , and a p - value < 0.05 was considered statistically significant .
all the analyses were performed by using spss version 20.0 ( ibm corporation , armonk , ny , usa ) .
carer dyads in the intervention group and 46 dyads in the control group were invited to participate in the study . for the intervention group ,
13 dyads refused , patients in four dyads were readmitted to the hospital , and 32 dyads were excluded because they were unable to be matched with a control dyad . for the control group , six dyads refused to join the study .
one dyad in the intervention group withdrew their consents before receiving the virtual ward service , because the patient was expecting to frequently travel to the people s republic of china in the near future and , therefore , could not receive the service . at 3 months
, 27 patients in the intervention group and 33 patients in the control group were successfully followed - up . among patients who were lost to follow - up , eleven died and one refused to complete the questionnaire in the intervention group , and six died and one was in a vegetative stage in the control group .
thus , a total of 39 matched patient pairs in the two groups were available for the analysis on hospital services utilization . for the qol , due to loss to follow - up and missing data at the item level ,
the results reported in tables 2 and 3 revealed that the intervention group showed a significantly greater reduction in the number of unplanned emergency hospital admissions ( 1.411.23 versus 0.771.31 ; p=0.049 ) .
although there were no significant differences in both the length of hospitalization via emergency admission ( 11.6217.91 versus 4.3826.41 ; p=0.14 ) and the number of emergency attendances ( 1.511.25 versus 1.081.48 ; p=0.29 ) in the past 90 days between the two groups , the decreases in these two clinical measures were greater in the intervention group ( table 2 ) .
sensitivity analysis by excluding those patients who had died during the study period also gives similar results on the three clinical outcomes ( table 3 ) .
for qol , patients receiving the virtual ward service reported higher mean values in the changes of the overall scores and the scores in all the six dimensions of mqolc - e from the baseline to the follow - up than patients receiving the community nursing service ( table 4 ) .
significant differences were observed in the overall qol scores ( 0.600.56 versus 0.070.56 ; p=0.02 ) and the three dimensions of food - related concerns ( 0.820.87 versus 0.140.95 ; p=0.003 ) , negative emotions ( 0.730.74 versus 0.021.03 ; p=0.01 ) , and existential distress ( 0.721.06 versus 0.150.81 ; p=0.04 ) .
our pilot study shows that for frail patients with chronic diseases , the virtual ward service , with physicians and nurses undertaking visits to the patient s home , results in a significantly greater reduction in the number of admissions via emergency admissions as compared to matched controls receiving the usual community nursing service . the result on frequency of admission via emergency admission remained significant in the sensitivity analysis by excluding those patients who died during the study period . although non - significant , the reductions in length of stay via emergency admission and emergency attendance were also greater in the intervention group .
consistent with a previous study , our study also showed that health care provided at home by a multidisciplinary team involving physicians , nurses , and carers is effective in reducing emergency visits than is the usual care provided by community nurses and carers.8 compared to a previous local randomized controlled trial ( rct ) which examined the effectiveness of nursing home visits driven by a protocol which used the omaha scheme and the standard community nursing service,18 our subjects were older and frailer , and they had to be taken care of , which means that they are expected to be at a higher risk of emergency hospitalization .
their study showed that home visits driven by a protocol that used the omaha scheme had a similar effect as the basic community nursing service on the frequency of hospitalization .
the current results highlight the potentially important role of the main feature of targeting those patients who are at high risk of emergency hospitalization in the virtual ward services , which distinguishes it from other programs designed to prevent hospitalization .
our study had provided new evidence for the efficacy of the virtual ward service , as compared to home visits by community nurses , in reducing the number of readmissions .
this suggests that providing a more intensive care at home by a team of multidisciplinary health care professionals might be more effective than a low intervention dose , ie , home visits delivered by community nurses only for frail older patients.18,19 this observation also echoed the views that patients with chronic , functional , and relatively intractable health problems require a higher level of intervention.20 however , further studies using an rct with adequate power on testing the effectiveness of the virtual ward service on the target population are warranted .
the mortality rate in the intervention group was higher than that in the control group , although the difference was not significant ( mcnemar test , p=0.27 ) .
it is possible that some of the patients were at their end stage of life and that the patients as well as their carers might prefer to stay at home and forgo life - sustaining treatment.21 although the accessibility of hospitals and the low cost for a hospital pay in hong kong might be important factors for unplanned readmission,16 both patients and their carers may not opt for this option unless necessary .
hospitalization inevitably induces stress both to patients and their family carers.22,23 repeated emergency hospital admissions are also a significant and disruptive event for families , because it may herald the possibility of an uncertain future and anticipated loss to both the families and the patients.24 thus , it is possible that the frail patients or their carers may feel that it is safer for the patients to stay in the hospital if their conditions are out of control even though both of them may not be well - prepared for such readmission.25 furthermore , many forms of care and support , particularly comfort measures like feeding and bathing , that family members normally provide to older adults with multiple comorbidities or impaired functional ability are to be continued but in a hospital setting.24 this situation is especially true in chinese society , because the chinese have a strong sense of moral obligation to take care of a sick family member.26 hence , it is very important to manage the patients condition by providing timely professional advice , such as a change of medication prescription , so that some emergency admissions could be avoided .
the close monitoring of the patients health condition and the prompt adjustment of medication orders are risk factors of readmission27 that can be remedied by better health care coordination , such as that provided by the virtual ward service .
patients receiving the virtual ward service reported greater improvements in the overall score and all the six dimension scores in qol as compared to patients receiving the community nursing service ; this is in line with the findings from a previous study on elderly patients with chronic heart failure.10 in particular , the changes in the overall qol score and the three dimensions of food - related concerns , negative emotions , and existential distress were statistically significant between the two groups .
the results might suggest that the virtual ward service may exert positive effects on the qol of the patients by providing individualized care , health education , and emotional support to the patients and their carers so that the conditions of the patients can be better monitored .
however , the results from our nonrandomized matched control study should be interpreted with caution because of potential bias due to patients loss to follow - ups .
first , this is a pilot study , and it may have produced imprecise estimates of the differences in the outcome variables between the groups .
nevertheless , our study has produced an estimate of the effect size of the virtual ward service to the usual community nursing service for future studies .
second , although we have successfully recruited matched controls by using the five criteria for comparison , it is still possible that we have not controlled other possible confounders , such as the characteristics of the carers and the study site , and this might have induced bias into the study results .
however , we were not able to recruit control subjects in the experimental hospitals due to the time constraint of this pilot study , and the small sample size precludes the inclusion of the carers characteristics in the analysis .
further studies should consider using rct with a larger sample size , to examine the effectiveness of the virtual ward service in the target population .
third , we have high attrition rates in patients in both groups , and this might have introduced bias in the results of qol .
fourth , we have a mixture of disease - specific patient groups including chronic obstructive pulmonary disease ( copd ) , chronic heart failure , cancer , and other diseases in our study .
each patient group might require different types of interventions at home , and some of the required interventions might not be covered by the virtual ward service .
thus , it may be possible that the impact of the service might differ in accordance with the disease types of the patients . given the encouraging results obtained in this pilot study , it is worthwhile to further investigate the effect of the virtual ward service on patients with some specific diseases , such as copd and chronic heart failure , who are at high risk of emergency hospitalization individually . finally , we did not collect cost information of the virtual ward and the usual community nursing service for this pilot study due to time and financial constraints .
because the virtual ward service is still available at the three experimental hospitals , one of the main focuses of further studies should be on the cost - effectiveness of the service as compared to the community nursing care .
supported by the results of this pilot study , the virtual ward service is effective in reducing unplanned hospital readmissions and improving the patients qol .
it is also potentially effective in reducing the patients length of stay via emergency admissions and emergency attendances .
these results support the potential benefits of virtual ward service for frail elderly patients who live with their carers .
Output:
| introductionattendance at emergency departments and unplanned hospital readmissions are common for frail older patients after discharge from hospitals .
a virtual ward service was piloted to deliver hospital - at - home services by community nurses and geriatricians to frail older patients immediately after their discharge from hospital to reduce emergency services utilization.objectivesthis study examined the impacts of the virtual ward service on changes in the patients emergency attendance and medical readmissions , and their quality of life ( qol).methodsa matched - control quasi - experimental study was conducted at four hospitals , with three providing the virtual ward service ( intervention ) and one providing the usual community nursing care ( control ) .
subjects in the intervention group were those who are at high risk of readmission and who are supported by home carers recruited from the three hospitals providing the virtual ward service . matched control patients were those recruited from the hospital providing usual care .
outcome measures include emergency attendance and medical readmission in the past 90 days as identified from medical records , and patient - reported qol as measured by the modified quality - of - life concerns in the end of life questionnaire ( chinese version ) .
wilcoxon signed - rank tests compared the changes in the outcome variables between groups.resultsa total of 39 patients in each of the two groups were recruited .
the virtual ward group showed a greater significant reduction in the number of unplanned emergency hospital readmissions ( 1.411.23 versus 0.771.31 ; p=0.049 ) and a significant improvement in their overall qol ( n=18 ; 0.600.56 versus 0.070.56 ; p=0.02 ) , but there was no significant difference in the number of emergency attendances ( 1.511.25 versus 1.081.48 ; p=0.29).conclusionthe study results support the effectiveness of the virtual ward service in reducing unplanned emergency medical readmissions and in improving the qol in frail older patients after discharge . |
PubmedSumm118778 | ***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: these were previously graded by pathologists using a three - tier system as low , intermediate or high grade tumors . in recent years
there has been a shift to a two - tier grading system classifying tumors as either low grade or high grade , .
low grade and high grade serous carcinomas of the ovary have differing histologic appearances , types of genetic mutations , clinical presentations , responsiveness to chemotherapy and prognosis , .
low grade serous carcinomas are less common than high grade serous carcinomas . to our knowledge
, the imaging appearance of low grade serous carcinoma ( lgsc ) of the ovary has not been previously described in the radiologic literature .
a combined search of the radiology and pathology database was performed to identify patients with a pathologic diagnosis of low grade serous carcinoma involving the ovary as well as cross - sectional imaging studies in pacs over an 8-year period .
after review of the pathology reports , 7 patients were excluded either due to lack of lgsc in the ovary ( n = 5 ) or only microscopic foci of lgsc in the ovary ( n = 2 ) at pathology . 4 of these patients had serous borderline tumors of the ovaries with low grade serous carcinoma peritoneal implants ( three synchronously and 1 metachronously 6 years later ) .
1 patient did not have a definitive diagnosis of low grade serous carcinoma the patient had a borderline tumor in the ovary with implants that were possibly low grade serous carcinoma . 1 patient had a borderline tumor of the ovary with a microscopic focus of low grade serous carcinoma . 1 patient had microscopic foci of low grade serous carcinoma on the surface of one ovary but no preoperative imaging of the low grade serous carcinoma in the contralateral ovary .
of the remaining 18 patients , 4 patients only had digitized film of the ct scans in pacs and were therefore excluded from analysis .
the ct was performed prior to chemotherapy in 12 of the 14 patients . in 10 patients
a single preoperative ct was available , and was performed a median of 20 days ( range 551 days ) prior to oophorectomy .
the initial scan was prior to chemotherapy in 3 of the 4 patients and was performed a median of 174 days ( range 89295 days ) prior to oophorectomy .
3 of the 4 patients each had 3 ct scans and 1 patient had 2 ct scans prior to oophorectomy .
the final ct scan prior to oophorectomy was performed a median of 30 days ( range 949 days ) before surgery .
for the 4 patients with multiple ct scans , the initial ct was used for describing the tumor findings in table 1 , table 2 while the findings on followup ct are noted in table 3 .
ct of the abdomen and pelvis was done in 13 patients , and 1 patient ( patient number 10 ) only had a pelvic ct .
ct was done with oral and intravenous contrast in 10 patients , with only oral contrast in 3 patients ( patient numbers 4 , 5 , 11 ) and with only intravenous contrast in 1 patient ( patient number 3 ) . in 2 patients ,
. 1 patient ( patient number 9 ) had pre and post intravenous contrast phase images .
1 patient ( patient number 14 ) had post intravenous contrast images in the renal corticomedullary and excretory phases .
an abdominal radiologist , with greater than 15 years of postfellowship experience in ct , evaluated each ct for the following characteristics presence of an adnexal mass , peritoneal implants , calcified nodes and ascites .
the adnexal masses were characterized as primarily ( > 75% ) cystic , mixed cystic solid , or primarily ( > 75% ) solid .
in addition to the following ct criteria , the solid or cystic nature of the mass was corroborated by ultrasound in 3 patients , by mri in 3 patients , by both ultrasound and mri in 1 patient , and by subsequent multiphase ct in 1 patient .
the presence of a cystic or solid component in the adnexal mass was corroborated by the gross pathologic description in 10 patients .
on ct , a component of the lesion was classified as cystic if it met one of the following criteria
attenuation < 40 hu , or if there were visible internal septations or mural nodularity , or if there was absence of enhancement on a multiphase study .
the attenuation of the cystic component was recorded by placing a region of interest encompassing at least two thirds of the component on an axial slice ( region of interest roi size median 764 mm range 526293 mm ) .
a component of the lesion was classified as solid if it met one of the following criteria central calcifications , density greater than pelvic muscle , or evidence of enhancement on a multiphase study .
as the bilateral adnexal masses and multiple peritoneal masses were confluent in some cases and the omental plaque had variable measurements depending on the axial slice , the largest measurement of the adnexal and peritoneal masses was obtained on an axial slice and the masses were classified as < 1 cm , 15 cm or > 5 cm in size .
ascites was recorded as present or absent and qualitatively categorized as minimal , small , moderate or large in volume . in patients who had multiple ct studies prior to surgical resection , change in the morphology of the primary and metastatic masses was qualitatively assessed .
a combined search of the radiology and pathology database was performed to identify patients with a pathologic diagnosis of low grade serous carcinoma involving the ovary as well as cross - sectional imaging studies in pacs over an 8-year period .
after review of the pathology reports , 7 patients were excluded either due to lack of lgsc in the ovary ( n = 5 ) or only microscopic foci of lgsc in the ovary ( n = 2 ) at pathology . 4 of these patients had serous borderline tumors of the ovaries with low grade serous carcinoma peritoneal implants ( three synchronously and 1 metachronously 6 years later ) .
1 patient did not have a definitive diagnosis of low grade serous carcinoma the patient had a borderline tumor in the ovary with implants that were possibly low grade serous carcinoma . 1 patient had a borderline tumor of the ovary with a microscopic focus of low grade serous carcinoma . 1 patient had microscopic foci of low grade serous carcinoma on the surface of one ovary but no preoperative imaging of the low grade serous carcinoma in the contralateral ovary .
of the remaining 18 patients , 4 patients only had digitized film of the ct scans in pacs and were therefore excluded from analysis .
the ct was performed prior to chemotherapy in 12 of the 14 patients . in 10 patients
a single preoperative ct was available , and was performed a median of 20 days ( range 551 days ) prior to oophorectomy .
the initial scan was prior to chemotherapy in 3 of the 4 patients and was performed a median of 174 days ( range 89295 days ) prior to oophorectomy .
3 of the 4 patients each had 3 ct scans and 1 patient had 2 ct scans prior to oophorectomy .
the final ct scan prior to oophorectomy was performed a median of 30 days ( range 949 days ) before surgery .
for the 4 patients with multiple ct scans , the initial ct was used for describing the tumor findings in table 1 , table 2 while the findings on followup ct are noted in table 3 .
ct of the abdomen and pelvis was done in 13 patients , and 1 patient ( patient number 10 ) only had a pelvic ct .
ct was done with oral and intravenous contrast in 10 patients , with only oral contrast in 3 patients ( patient numbers 4 , 5 , 11 ) and with only intravenous contrast in 1 patient ( patient number 3 ) . in 2 patients ,
. 1 patient ( patient number 9 ) had pre and post intravenous contrast phase images .
1 patient ( patient number 14 ) had post intravenous contrast images in the renal corticomedullary and excretory phases .
an abdominal radiologist , with greater than 15 years of postfellowship experience in ct , evaluated each ct for the following characteristics presence of an adnexal mass , peritoneal implants , calcified nodes and ascites .
the adnexal masses were characterized as primarily ( > 75% ) cystic , mixed cystic solid , or primarily ( > 75% ) solid .
in addition to the following ct criteria , the solid or cystic nature of the mass was corroborated by ultrasound in 3 patients , by mri in 3 patients , by both ultrasound and mri in 1 patient , and by subsequent multiphase ct in 1 patient .
the presence of a cystic or solid component in the adnexal mass was corroborated by the gross pathologic description in 10 patients .
on ct , a component of the lesion was classified as cystic if it met one of the following criteria
attenuation < 40 hu , or if there were visible internal septations or mural nodularity , or if there was absence of enhancement on a multiphase study .
the attenuation of the cystic component was recorded by placing a region of interest encompassing at least two thirds of the component on an axial slice ( region of interest roi size median 764 mm range 526293 mm ) .
a component of the lesion was classified as solid if it met one of the following criteria central calcifications , density greater than pelvic muscle , or evidence of enhancement on a multiphase study . as the bilateral adnexal masses and multiple peritoneal masses were confluent in some cases and the omental plaque had variable measurements depending on the axial slice , the largest measurement of the adnexal and peritoneal masses was obtained on an axial slice and the masses were classified as < 1 cm , 15 cm or > 5 cm in size .
ascites was recorded as present or absent and qualitatively categorized as minimal , small , moderate or large in volume . in patients who had multiple ct studies prior to surgical resection , change in the morphology of the primary and metastatic masses was qualitatively assessed .
6 patients had low grade serous carcinoma without associated serous borderline tumor while 8 patients had a combined diagnosis of low grade serous carcinoma and serous borderline tumor . for the 6 patients with only low grade serous carcinoma at pathology , the tumor involved both ovaries in all cases , and was possibly peritoneal in origin in 2 patients .
for the 8 patients with a combined diagnosis of low grade serous carcinoma ( lgsc ) and serous borderline tumor ( sbt ) of the ovary , both tumors were present bilaterally in 3 patients .
2 patients had a co - existing lgsc and sbt in one ovary and a lgsc in the contralateral ovary .
1 patient had a co - existing lgsc and sbt in one ovary and a sbt in the contralateral ovary . 1 patient had a co - existing lgsc and sbt in one - ovary and tumor emboli in the hilar vessels of the contralateral ovary .
1 patient with a remote history of unilateral oophorectomy for a benign cyst had a co - existing lgsc and sbt in the remaining contralateral ovary .
table 1 gives the ct findings in 6 patients with low grade serous carcinoma without co - existing serous borderline tumor .
the tumors were primarily solid or mixed solid cystic in 4 of the 6 patients ( fig .
1 patient had a complex adnexal mass that was indeterminate for solid or cystic lesion on ct .
calcification was present in about half of the adnexal masses ( 7 of 12 ovaries ) .
table 2 gives the ct findings in 8 patients with low grade serous carcinoma present in conjunction with serous borderline tumor .
the tumors were complex primarily cystic lesions in 7 of the 8 patients , 4 of whom had co - existing soft tissue nodules , and 3 of whom had septations ( fig .
calcification was present in half of the adnexal masses ( 7 of 14 ovaries ) .
2 patients also had calcified nodes . in the 3 patients with differing pathology between the right and left ovaries , i.e. co - existing lgsc and sbt in one ovary and a lgsc or sbt in the contralateral ovary
ascites was absent in 5 patients and was minimal or small in volume in 3 patients .
table 3 gives the ct findings in 4 patients who had multiple ct scans prior to oophorectomy .
increased calcification of the adnexal , peritoneal and nodal masses was noted on the followup study ( fig .
6 patients had low grade serous carcinoma without associated serous borderline tumor while 8 patients had a combined diagnosis of low grade serous carcinoma and serous borderline tumor . for the 6 patients with only low grade serous carcinoma at pathology , the tumor involved both ovaries in all cases , and was possibly peritoneal in origin in 2 patients .
for the 8 patients with a combined diagnosis of low grade serous carcinoma ( lgsc ) and serous borderline tumor ( sbt ) of the ovary , both tumors were present bilaterally in 3 patients .
2 patients had a co - existing lgsc and sbt in one ovary and a lgsc in the contralateral ovary .
1 patient had a co - existing lgsc and sbt in one ovary and a sbt in the contralateral ovary . 1 patient had a co - existing lgsc and sbt in one - ovary and tumor emboli in the hilar vessels of the contralateral ovary .
1 patient with a remote history of unilateral oophorectomy for a benign cyst had a co - existing lgsc and sbt in the remaining contralateral ovary .
table 1 gives the ct findings in 6 patients with low grade serous carcinoma without co - existing serous borderline tumor .
the tumors were primarily solid or mixed solid cystic in 4 of the 6 patients ( fig .
1 patient had a complex adnexal mass that was indeterminate for solid or cystic lesion on ct .
calcification was present in about half of the adnexal masses ( 7 of 12 ovaries ) .
table 2 gives the ct findings in 8 patients with low grade serous carcinoma present in conjunction with serous borderline tumor .
the tumors were complex primarily cystic lesions in 7 of the 8 patients , 4 of whom had co - existing soft tissue nodules , and 3 of whom had septations ( fig .
calcification was present in half of the adnexal masses ( 7 of 14 ovaries ) .
2 patients also had calcified nodes . in the 3 patients with differing pathology between the right and left ovaries , i.e. co - existing lgsc and sbt in one ovary and a lgsc or sbt in the contralateral ovary , there was no visible difference in morphology on ct .
ascites was absent in 5 patients and was minimal or small in volume in 3 patients .
table 3 gives the ct findings in 4 patients who had multiple ct scans prior to oophorectomy .
increased calcification of the adnexal , peritoneal and nodal masses was noted on the followup study ( fig .
the majority are high grade serous carcinomas ( hgsc ) while an estimated 310% are low grade serous carcinomas ( lgsc ) , , .
significant clinical , pathologic , and pathogenesis differences have been described between lgsc and hgsc .
patients with lgsc tend to be younger than patients with hgsc and to have a better survival .
in one study , mean age and mean survival were 55 years and 99 months for lgsc and 63 years and 57 months for hgsc . at pathology , lgsc and hgsc
differ in the degree of nuclear atypia and mitotic rate with less atypia and fewer mitoses in lgsc . on a genetic level , kras or braf
lgsc is theorized to arise more slowly from precursor lesions while hgsc develops more rapidly possibly arising from tubal intraepithelial carcinoma .
the pathogenesis of lgsc is believed to occur step - wise from cystadenoma to atypical proliferative serous tumor ( apst ) to noninvasive micropapillary serous borderline tumor ( sbt ) to low grade serous carcinoma ( lgsc ) .
this development of lgsc from serous borderline tumors likely accounts for the association between the two entities in the literature as well as in our study .
approximately 60% of lgsc are reported to be associated with a sbt and patients with advanced stage sbt often recur as lgsc .
the distinction between lgsc and sbt is made based on the presence of destructive stromal invasion in lgsc on histology . given the microscopic nature of this distinction , distinguishing the lgsc and sbt components in ovaries with both lesions on a gross scale on ct will likely be challenging .
on mri , sbt have a range of appearances which include unilocular or multilocular cysts with papillary projections , septated cystic lesions , or mixed solid cystic masses with enhancing soft tissue components , , .
high signal intensity is reported in the cyst fluid on t1 weighted images in some cases suggesting hemorrhage or proteinaceous material .
this likely accounts for the cyst fluid being higher than water density on ct in several cases in our study .
the mixed solid cystic mass appearance of borderline tumors is similar to that of ovarian malignancy .
psammoma bodies are calcified extracellular bodies that can occur in serous ovarian and peritoneal neoplasms as well as in thyroid masses .
they are common in lgsc . in a series of 53 patients , 29 ( 56% ) patients had psammoma bodies at pathology without meeting the definition of psammomacarcinoma , . in order for a serous neoplasm to be considered a psammomacarcinoma
, at least 75% of the papillae have to contain psammoma bodies in addition to other pathologic criteria , .
there are a few clinical case reports of psammomacarcinomas and calcification in serous neoplasms has also been reported on ct , , , .
this appearance of a calcified solid or complex cystic mass places lgsc in the differential for adnexal masses that can calcify .
these include exophytic uterine or broad ligament fibroids and ovarian lesions such as brenner tumors , fibromas and dermoids .
brenner tumors can be complex cystic or solid masses and have extensive calcifications similar to the lgsc tumors in our study
fibromas have focal or diffuse dense calcification in a minority of cases ( < 10% ) and calcification is rare in thecomas , , , .
features that can distinguish lgsc from benign entities include the presence of nodal calcification or peritoneal masses .
nodal calcification was seen in 4 of the 14 patients with lgsc in our study . in the absence of an infectious or inflammatory etiology
, the presence of nodal calcification in a patient with a calcified adnexal mass raises the concern for a serous neoplasm .
peritoneal implants are also seen in lgsc but not in patients with benign adnexal masses .
ascites was not a prominent finding in the patients with lgsc in our study , even in those with peritoneal masses and serial ct scans .
ascites is also uncommon in fibromas , with meigs syndrome occurring in 1% of cases . in the few patients with multiple ct scans ,
the adnexal and peritoneal masses showed increased calcification over time possibly due to the natural course of the disease and/or secondary to chemotherapy effect .
although the number of patients in this study is small , the ct findings of this uncommon tumor were evaluated in patients in whom the diagnosis of lgsc had been made by specialty gynecologic pathologists from a single institution .
low grade serous carcinoma of the ovary can appear as a solid , mixed solid cystic , or complex primarily cystic adnexal mass , and the appearance may be due to a co - existing serous borderline tumor .
lgsc is a diagnostic consideration in patients with a calcified adnexal mass and concurrent peritoneal masses or calcified nodes on ct .
Output:
| objectiveto evaluate the ct features of pathologically proven low grade serous carcinoma ( lgsc ) of the ovary.methodspatients with a pathologic diagnosis of lgsc and ct prior to oophorectomy were retrospectively identified .
the ct scans in 14 patients were available and were analyzed for an adnexal mass , peritoneal mass and ascites .
the adnexal mass was characterized as complex primarily cystic , mixed cystic solid , or primarily solid .
calcification in the adnexal and peritoneal masses and nodes was noted.resultspathology revealed 6 patients had lgsc and 8 patients had a combined diagnosis of lgsc and serous borderline tumor ( sbt ) of the ovary .
of the 6 patients with only lgsc , 4 had primarily solid or mixed solid cystic adnexal masses and 5 had peritoneal masses .
calcification was present in the adnexal and peritoneal masses in 4 patients , and in nodes in 2 patients .
of the 8 patients with co - existing lgsc and sbt , 7 had complex primarily cystic adnexal masses and 6 had peritoneal masses .
calcification was present in the adnexal and peritoneal masses in 5 patients and in nodes in 2 patients.conclusionlgsc can appear as a solid , mixed solid cystic , or complex primarily cystic ovarian mass , and the appearance may be due to a co - existing sbt .
calcification of the adnexal and peritoneal masses appears to be common .
lgsc is a diagnostic consideration in patients with a calcified adnexal mass and concurrent peritoneal masses or calcified nodes on ct . |
PubmedSumm118779 | ***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 oxygen species ( ros ) are chemically reactive molecules that contain oxygen [ 1 , 2 ] .
endogenous ros are produced as byproducts during aerobic respiration or by oxidation reactions catalyzed by metal and oxidoreductase enzymes such as phenoloxidases ( pos ) [ 3 , 4 ] .
pos , together with tyrosinases , catechol oxidase , and hemocyanin , belong to the type 3 copper protein family , all of which have an active site composed of two histidine - coordinated copper atoms [ 5 , 6 ] .
po possesses both monophenol monooxygenase activity ( ec 1.14.18.1 , tyrosine , dihydroxyphenylalanine , oxygen , and oxidoreductase ) and o - diphenoloxidase activity ( ec 1.10.3.1 , o - diphenol , oxygen , and oxidoreductase ) [ 7 , 8 ] .
therefore , pos can catalyze the hydroxylation of monophenols to o - diphenols and subsequent oxidation of o - diphenols to corresponding highly reactive o - quinones .
po - generated quinones act as cross - linkers for wound healing or polymerize to form melanin capsules around the invading parasites and parasitoids [ 10 , 11 ] or interact with oxygen to form ros to kill microbial pathogens directly [ 4 , 12 ] .
although type 3 copper proteins are distributed among almost all organisms , pos are mainly found in arthropods including insects [ 6 , 13 ] . in insects ,
the number of po genes ranges from ten in the mosquito aedes aegypti to just one in the honeybee apis mellifera . in most lepidoptera
, there are two po genes . for example , two po sequences have been reported in the silkworm bombyx mori , the beetle holotrichia diomphalia , and the tobacco hornworm manduca sexta
. however , three transcripts for potential po were identified in the transcriptome of asian corn borer , ostrinia furnacalis ( gune ) .
po is predominantly synthesized in hemocytes as a zymogen called prophenoloxidase ( ppo ) and released into hemolymph ( insect blood ) to perform functions .
however , all arthropod ppos studied so far lack a signal peptide for secretion into hemolymph [ 11 , 16 ] .
ppo is believed to be released after rupture of hemocytes [ 21 , 22 ] .
then inactive ppo is converted into active po form by proteolytic cleavage in hemolymph [ 2325 ] .
the cleavage site in ppo has been experimentally confirmed in several insect species , including arg - phe in b. mori ppo , arg - phe in m. sexta ppo [ 27 , 28 ] , and arg - phe followed by the second cleavage at arg - ala in h. diomphalia ppo [ 23 , 24 ] . in vitro
, ppo can also be activated without proteolytic cleavage by certain chemicals such as ethanol or detergents ( e.g. , sodium dodecyl sulfate ( sds ) , cetylpyridinium chloride ( cpc ) ) [ 29 , 30 ] .
a model has generally been accepted for ppo activation in insects : upon pathogenic infections or physical injuries , a serine protease cascade is triggered to activate the prophenoloxidase - activating protease and prophenoloxidase - activating protease then cleaves ppo at a conserved peptide bond to produce po [ 11 , 20 ] .
this process involves multiple proteins , including pattern recognition proteins , a series of serine proteases , serine protease homologs , and serine protease inhibitors .
the asian corn borer , o. furnacalis ( gune ) ( lepidoptera : crambidae ) , is an important insect pest in asia , causing serious damage to corn , sorghum , and millet .
our previous work identified three transcripts for potential ppos in the transcriptome of this pest . among these , only one , designated as ofppo2 , contained a complete open reading frame [ 20 , 37 ] . in this study , we cloned a full - length nucleotide sequence for another two o. furnacalis ppos , which we called ofppo1 and ofppo3 ( genbank : kx437621 ) .
ofppo1 from the transcriptome is actually an assembly mosaic , consisting of two variant ppo sequences , ofppo1a ( genbank : kx452359 ) and ofppo1b ( genbank : kx437622 ) , which are 86.82% identical in amino acid sequences .
we investigated the expression profiles of these 4 ppos in different developmental stages , in different tissues , and upon the infection of different microorganisms .
additionally , we performed the recombinant expression for these 4 proteins using a prokaryotic expression system .
o. furnacalis larvae were reared on an artificial diet at 28c under a relative humidity of 7090% and a photoperiod of 16 h light and 8 h darkness .
three transcripts for potential ppos ( cl5552.contig1 , cl997.contig1 , and unigene28348 ) were previously identified from o. furnacalis transcriptome . among these , cl997.contig1 was a complete cdna sequence , but another two transcripts ( 1,299-bp cl5552.contig1 and 1,152-bp unigene28348 ) were incomplete . on the basis of these two fragments , primers ( see table s1 in supplementary material available at http://dx.doi.org/10.1155/2016/1781803 )
were designed for 5 and 3 rapid amplification of cdna ends ( race ) to obtain the remaining sequences .
the 5 and 3 race reactions were performed according to the manufacturer 's instructions for its race kit ( takara , biotechnology ( dalian ) co. , ltd . ,
china ) with cdna from the whole body of fifth - instar o. furnacalis larvae collected 24 h after injection with 3 l of micrococcus luteus ( 3 g/l ) .
briefly , after the first - round 3 race reaction using primer f1 ( table s1 ) , a 1,566-bp fragment with 225 bp at 5-end covered by cl5552.contig1 was obtained .
it was then assembled into a 2,865-bp cdna sequence ( ppo1-assembled in figure 1(a ) ) combined with cl5552.contig1 ( figure 1(a ) ) .
however , two variant pcr products , which are both inconsistent with expected ppo1-assembled , were amplified with selected primer pairs f3/r1 or f3/r2 ( figure 1(a ) , table s1 ) .
ppo1a-1st and ppo1b-1st following the manufacturer 's instructions ( figure 1(a ) ) .
the resulting products were cloned and sequenced . after assembling , primers ( table s1 ) were designed to amplify the full - length cdna encompassing the entire reading frame using the same larval cdna for race .
the final pcr products ( ppo1a and ppo1b ) were cloned into pmd19-t vector ( takara , biotechnology ( dalian ) co. , ltd , china ) , and the nucleotide sequences were confirmed by dna sequencing .
we carried out a series of sequence analyses for ofppo1a , ofppo1b , ofppo2 , and ofppo3 .
the deduced amino acid sequences were obtained by using the translate tool provided by the swiss institute bioinformatics .
analysis of deduced amino acid sequences , including prediction of signal peptide , molecular weight , and isoelectric point , was executed in the expasy ( expert protein analysis system ) proteomics server ( http://www.expasy.org/ ) .
characteristic domains or motifs were identified using dnassist prosite profile database ( http://prosite.expasy.org/scanprosite/ ) . to investigate the phylogenetic relationship between o. furnacalis ppos and other arthropod ppos , prophenoloxidase
was used as a keyword to search the nonredundant database from the national center for biotechnology information ( ncbi ; https://www.ncbi.nlm.nih.gov/ ) .
the retrieved ppo sequences were aligned with o. furnacalis ppo sequences using the clustal w program .
phylogenetic trees were constructed by the neighbor - joining method using mega version 5 software . for neighbor - joining method ,
gaps were treated as characters , and statistical analysis was performed using the bootstrap method with 1000 replicates . to investigate the changes of o. furnacalis ppo transcript levels in several developmental stages , total rna samples were individually prepared ( n = 5 ) from three different stages including egg , larvae , and pupa using trnzol reagent ( tiangen , biotech ( beijing ) co. , ltd . , china )
. 1 g of rna samples equally from 5 individual rna samples in each stage was treated with dnase i ( tiangen , biotech ( beijing ) co. , ltd . ,
china ) and converted into first - strand cdna from an oligo ( dt ) primer following the instructions for quantscriptrt kit ( tiangen , biotech ( beijing ) co. , ltd , china ) .
the cdna products independently from 3 biological replicates were diluted 10-fold for use as template in rt - pcr experiments .
o. furnacalis ribosomal protein l8 ( rpl8 ) was used as an internal standard to adjust the template amounts in preliminary pcr experiments .
the thermal cycling conditions were 94c for 2 min and then 28 cycles of 94c for 30 s , 58c for 30 s , and 72c for 30 s followed by incubation at 72c for 10 min .
the pcr products were separated by electrophoresis on a 1.5% agarose gel . to determine the expression patterns of o. furnacalis ppos in different tissues , total rna samples were isolated separately from combined heads , midguts , fat bodies , and hemocytes from 20-day - zero fifth - instar larvae .
the synthesis of first - strand cdna and rt - pcr analysis was performed as described above . to check the expression of o. furnacalis ppos after different microbial injections , day
one fifth - instar larvae from the same batch were injected into the hemocele with 3 l of sterile water containing formalin - killed escherichia coli dh5 ( 2 10 cells/l ) , dried m. luteus ( 3 g/l ) , beauveria bassiana suspension ( 2 10 conidia/l , b. bassiana conidia suspension was prepared as described previously ) , or sterile water as a control .
after 20 h ( 10 h for b. bassiana treatment ) , five larvae were collected from the challenged group and 5 from the control group , and total rna samples were prepared from each larva .
the following rt - pcr analysis was conducted as described above . to express recombinant o. furnacalis ppos in e. coli ,
briefly , the vector pet28a ( novagen , germany ) and the coding region of mature ofppo1a , ofppo1b , ofppo2 , and ofppo3 were amplified by pcr , respectively , using specific primers listed in table s1 .
the forward primer for vector amplification ( 5-caccaccaccaccaccactgagat-3 ) matched to the 3 side of the polylinker region of expression vector pet28a .
the reverse primer for vector amplification ( 5-gtgatgatgatgatgatggctgct-3 ) was reversely complementary to the 5 side of the polylinker .
the primers for ofppo amplification had specific sequences and additional 15 nucleotides overlapping with the vector ends .
the pcr products containing amplified vector and each ofppo was mixed and digested with dpni ( takara , biotechnology ( dalian ) co. , ltd . ,
after sequence verification , the resulting plasmids encoding correct ofppos were further transformed into e. coli strain bl21 ( de3 ) cells and plated onto luria bertani ( lb ) agar with kanamycin ( 0.05 mg / ml ) for selection .
for the coexpression of two ofppos , the constructed plasmids encoding ofppo1a or ofppo1b were individually transformed to e. coli bl21 ( de3 ) cells which already contained plasmids encoding ofppo2 or ofppo3 , named as ofppo1a and ofppo2 ( ofppo1a/2 ) , ofppo1a and ofppo3 ( ofppo1a/3 ) , ofppo1b and ofppo2 ( ofppo1b/2 ) , and ofppo1b and ofppo3 ( ofppo1b/3 ) .
then single colony was picked and inoculated into 7 ml of lb medium with kanamycin ( 0.05 mg / ml ) and incubated overnight at 37c with constant shaking . the following day , 2 ml of the overnight cultures was inoculated into 100 ml of lb with kanamycin ( 0.05 mg / ml ) .
when od600 of the culture reached 0.7 , isopropyl thio--d - galactoside ( iptg ) was added to a final concentration of 0.1 mm , and the recombinant ppo proteins were expressed for 12 h at 18c .
the bacteria were harvested by centrifugation at 10,000 g for 15 min and resuspended in lysis buffer ( 50 mm sodium phosphate , 300 mm nacl , 10 mm imidazole , ph 8.0 ) to a uniform od600 to ensure equal protein loading .
cells were lysed by sonication and then centrifuged at 10,000 g for 30 min .
the cleared supernatant was recorded as soluble fraction ( which contained the soluble recombinant ppos ) while the cell debris was recorded as insoluble fraction ( which contained the insoluble recombinant ppos ) . for sds - page ,
protein samples were treated with 2 sds sample buffer containing dithiothreitol ( dtt ) at 95c for 5 min and then separated by 10% sds - page .
for immunoblot analysis , proteins were transferred onto a nitrocellulose membrane and detected with mouse anti - his ( 1 : 2,000 ) as primary antibody .
antibody binding was visualized using alkaline phosphatase - conjugated goat anti - mouse or anti - rabbit igg ( 1 : 1,500 ) and 5-bromo-4-chloro-3-indolyl phosphate / nitro blue tetrazolium ( bcip / nbt ) staining buffer containing 165 g / ml bcip and 330 g / ml nbt in 100 mm tris ( ph 9.5 ) , 150 mm nacl , and 5 mm mgcl2 . to check the po activity of recombinant proteins , a convenient way was utilized as described by li et al . .
briefly , cu was also added into the culture to a final concentration of 0.5 mm upon the addition of iptg . following the recombinant expression
as described above , 1 ml of e. coli culture expressing each ofppo was centrifuged at 10,000 g for 3 min .
the resulting e. coli cells were washed using 10 mm tris buffer ( ph7.4 ) three times and then suspended in 30% ethanol for nonproteolytic activation of recombinant ppos .
after incubation at room temperature for 30 min , the reaction mixture was centrifuged at 10,000 g for 3 min .
the cell pellet containing ppos was then incubated with 250 l of dopamine ( 10 mm ) for 5 min .
then po activity of each sample was measured by monitoring a490 in a microplate reader ( bio - tek instrument , inc . ) .
one unit of po activity was defined as the amount of enzyme producing an increase in absorbance ( a490 ) of 0.001 per min .
with next generation high - throughput sequencing , we obtained an o. furnacalis transcriptome dataset containing 62,382 unigenes . among these ,
three ( 1,299-bp cl5552.contig1 , 2,366-bp cl997.contig1 , and 1,153-bp unigene28348 ) were predicted to encode potential ppos .
the 2,366-bp cl997.contig1 contains a complete 2,079-bp open reading frame and encodes a polypeptide sequence with 100% identity to o. furnacalis ppo ( genbank : abc59699 ) previously reported by feng et al . .
we performed 5- and 3-race to obtain the missing ends of the transcript cl5552.contig1 and unigene28348 .
the obtained full - length cdna was nominated as ofppo1a , ofppo1b , and ofppo3 , respectively .
they were submitted to ncbi and assigned the accession number as kx452359 , kx437622 , and kx437621 , respectively . ofppo1a and ofppo1b matched with the 3- and 5-end of cl5552.contig1 , respectively ( figure 1(a ) ) .
we conducted pcr using the primers common in both ofppo1a and ofppo1b ( table s1 ) and subjected the pcr products for sequencing .
among 12 clones randomly selected , 6 ones were identical to ofppo1a while the other 6 were identical to ofppo1b .
this indicated that ofppo1a and ofppo1b were expressed with the same abundance in o. furnacalis larvae .
the full - length cdna of ofppo1a , ofppo1b , and ofppo3 contains 2,462 , 2,391 , and 2,388 nucleotides , with a 2,052- , 2,058- , and 2,100-bp open reading frame , respectively ( figures 1 and 2 ) .
a poly(a ) tail was found in the cdna sequences of ofppo1b and ofppo3 , but not in ofppo1a .
the conceptual proteins deduced from nucleotide sequences of ofppo1a , ofppo1b , and ofppo3 cdna consist of 683 , 685 , and 699 amino acid residues , respectively ( figures 1 and 2 ) .
all four o. furnacalis ppos , including the previous ofppo2 , lack a typical secretion signal peptide at their n - terminal regions .
the calculated molecular mass and isoelectric point of the deduced proteins are 78.6 kda and 6.59 for ppo1a , 78.6 kda and 5.99 for ppo1b , 79.8 kda and 5.72 for ppo2 , and 81.0 kda and 7.41 for ppo3 , respectively . to clarify whether the amino acid residues and motifs critical for ppo activation and activity were also conserved in o. furnacalis ppos , the deduced amino acid sequences of four o. furnacalis ppos were aligned with well - characterized ppos from b. mori , m. sexta [ 19 , 42 ] , and h. diomphalia [ 23 , 24 ] .
the alignments revealed that 6 key regions were highly conserved in 4 o. furnacalis ppos ( figure 3 ) .
the ofppos contain a conserved sequence ( arg - phe - gly ) around the cleavage and activation site : rf in ofppo1a , rf in ofppo1b , rf in ofppo2 , and rf in ofppo3 ( figure 3(a ) ) .
they possibly contain another proteolytic cleavage site : ra in ofppo1a , ka in ofppo1b , qa in ofppo2 , and ea in ofppo3 ( figure 3(a ) ) .
two copper binding sites , cua and cub , are very similar among these proteins : 198246 and 358413 in ofppo1a , 199247 and 359414 in ofppo1b , 201250 and 358413 in ofppo2 , and 203254 and 362417 in ofppo3 , respectively .
these two copper binding sites carry three indispensable histidine residues in each site at h - h - h and h - h - h in ofppo1a , h - h - h and h - hh in ofppo1b , h - h - h and h - h - h in ofppo2 , and h - h - h and h - h - h in ofppo3 , respectively .
these conserved histidine residues are likely to be involved in the copper binding ( figures 3(b ) and 3(c ) ) .
moreover , cua contains hemocyanin encoding patterns like signature at hhwhwhlv in ofppo1a , hhwhwhlv in ofppo1b , hhwhwhlv in ofppo2 , and hhwhwhli in ofppo3 , respectively .
cub contains both hemocyanin signatures ( tamrdpffy in ofppo1a , tamrdpffy in ofppo1b , ttmrdpffy in ofppo2 , and ttmrdpyfy in ofppo3 ) and tyrosinase signatures ( dpffyrwhayvd in ofppo1a , dpffyrwhafvd in ofppo1b , dpffyrwhafid in ofppo2 , and dpyfyrwhafid in ofppo3 ) ( figures 3(b ) and 3(c ) ) .
additionally , two conserved motifs are present in the c - terminal end of all 4 ofppos : one ( cgcgwph / qhml ) matches the thiol ester region of -macroglobulin and complement proteins c3 and c4 , and the other one ( mgfpfdr ) is nearly identical in all compared ppos ( figure 3(d ) ) . the catalytic residue ( e364 ) key to the hydroxylation and oxidation activities of anopheles gambiae ppo8
is identified as e in ofppo1a , e in ofppo1b , e in ofppo2 , e in ofppo3 , respectively . besides
, two disulfide bonds are predicted to be in the ofppos based on the comparisons with previously characterized m. sexta ppos and a. gambiae ppo8 : cys-581/cys-623 and cys-583/cys-630 in ofppo1a , cys-582/cys-624 and cys-584/cys-631 in ofppo1b , cys-583/cys-627 and cys-585/cys-634 in ofppo2 , and cys-589/cys-634 and cys-591/cys-641 in ofppo3 ( figures 1(b ) and 2 ) .
all above results suggest that the obtained 4 nucleotide acid sequences ( ofppo1a - ofppo3 ) encode functional ppo proteins .
database search and sequence alignment indicated that 4 o. furnacalis ppos exhibited high amino acid sequence similarity ( 42%79% identity ) with ppos from other insect species : ofppo1a , ofppo1b , ofppo2 , and ofppo3 are most similar in amino acid sequences to b. mori ppo1 ( aag09304 ) , mythimna separata ppo ( bam76811 ) , galleria mellonella ppo2 ( aaq75026 ) , and g. mellonella ppo2 ( aaq75026 ) , with the sequence identity of 74.5% , 74.1% , 79.3% , and 70.5% , respectively .
a phylogenetic analysis was performed to investigate the evolutionary relationships between ofppos and other homologs .
as shown in figure 4 , insect and crustacean ppos form separate clades in the phylogenetic tree .
the aligned insect ppos ( totally 89 ppos from 34 insect species ) are clustered into six distinct groups , including the subfamilies for two lepidopteran ppos , two dipteran ppos , one coleopteran ppo , and one hymenopteran ppo .
the only inconsistency is hemiptera ppo ( choristoneura fumiferana ppo2 , abw16862 ) is assigned to the group of lepidopteran ppos .
these six groups are divided into three major clades : clade a consists of the conserved ppos distributed among various insect orders , whereas clades b and c comprise the paralogs specifically present in lepidoptera and diptera , respectively ( figure 4 ) .
o. furnacalis ppo1a and ppo1b clustered with lepidopteran ppos in clade a and ofppo2 and ofppo3 grouped with lepidopteran ppos in clade b. we analyzed the mrna levels of 4 o. furnacalis ppos in various development stages , different tissues , and different pathogen challenges using semiquantitative rt - pcr methods . as shown in figure 5 , the four o. furnacalis ppos exhibited distinct expression patterns .
the ofppo1a transcript was at the highest levels in eggs and the fifth - instar larval stage and then in the pupae .
this transcript was barely detectable in the first to fourth - instar larval stage , especially in the first and second - instar larval stage . ofppo1b and
ofppo2 were expressed in all tested developmental stages , including egg , larval , and pupal stages .
however , ofppo1b was expressed at the highest levels in eggs while ofppo2 was expressed at similar levels in all stages .
the ofppo3 mrna level increased from the second - instar larval stage , reached a maximum at the fifth - instar stage , and decreased dramatically in the pupal stage ( figure 5(a ) ) .
rt - pcr analyses showed that the 4 o. furnacalis ppo mrnas were all detected in the hemocytes at the highest levels among the tested four tissues including heads , guts , hemocytes , and fat bodies .
ofppo1b mrna was not detected in guts and fat bodies ( figure 5(b ) ) . to check the o. furnacalis ppo expression patterns after exposure to microbial elicitors
, we analyzed their transcript level after o. furnacalis larvae were injected with e. coli , m. luteus , b. bassiana , or water as a control .
the result from rt - pcr assay indicated that all 4 o. furnacalis ppo mrna levels clearly increased in the larva challenged by bacteria or fungi , especially in the e. coli - injected larvae .
injection of m. luteus or b. bassiana resulted in a much smaller increase in the ofppo1a transcript level compared to the treatment with e. coli ( figure 5(c ) ) .
as a first step to biochemically characterize o. furnacalis ppos , we tried to produce recombinant proteins using prokaryotic expression system .
after several preliminary experiments ( data not shown ) , we selected the pet system for recombinant o. furnacalis ppo production , in which the inserted o. furnacalis ppo genes were under control of strong bacteriophage t7 transcription and translation signals and their expression was induced by providing a source of t7 rna polymerase in the host bl21 ( de3 ) cells .
using a highly simplified and efficient pcr - based cloning technique , the complete open reading frame of 4 o. furnacalis ppos was successfully inserted into the pet28a vector individually . in the constructed plasmids ,
his tags were added into the amino- and carboxyl - terminus of recombinant ppo proteins , respectively ( figure s1 ) . additionally , we successfully transformed dual plasmids into bl21 ( de3 ) cells in order to express pairs of ppos simultaneously , including ofppo1a and ofppo2 , ofppo1a and ofppo3 , ofppo1b and ofppo2 , and ofppo1b and ofppo3 ( figure s3a ) .
the recombinant expression of 4 o. furnacalis ppos was evaluated at different temperatures and induction conditions to determine the optimum parameters for protein expression ( data not shown ) .
eventually , three of four o. furnacalis ppos ( ofppo1b , ofppo2 , and ofppo3 , but not ofppo1a ) were successfully expressed under the iptg induction ( figure 6(a ) ) .
although the insect - produced ppos are soluble proteins [ 24 , 41 , 42 ] , large proportions of recombinant ofppo1b , ofppo2 , and ofppo3 formed insoluble aggregates in the e. coli cells even using a low concentration of iptg ( 0.1 mm ) and a relatively low temperature ( 18c ) .
these aggregates fractionated with the cell debris following lysis ( figure 6(a ) ) . under the same induction and lysis conditions , the solubility of recombinant ofppo2 was obviously higher than that of recombinant ofppo1b and ofppo3 .
the soluble fractions of recombinant ofppo1b and ofppo3 were nearly undetectable in polyacrylamide gel electrophoresis ( figure 6(a ) ) .
additionally , recombinant ofppo1b , ofppo2 , and ofppo3 , but not ofppo1a , could be recognized by antibody against his - tag ( figure 6(b ) ) .
the cultured cells were treated with 30% ethanol for activating recombinant ofppos as described by li et al . .
the resulting po activity was checked using dopamine as substrate . as figure 6(c ) shown , four ethanol - treated ofppos with the exception of ofppo1a exhibited detectable po activities .
there was no significant difference among the po activity of recombinants ofppo1b , ofppo2 , and ofppo3 .
phenoloxidase ( po ) is the important enzyme in the melanin synthesis , a pathway in which some secondary reaction products including reactive oxygen species ( ros ) and reactive nitrogen species ( rns ) are also generated [ 3 , 11 ] .
po plays a key role in multiple physiological processes including wound healing , hemolymph clotting , and innate immune response especially in defensive encapsulation and melanization of foreign organisms [ 11 , 46 ] . in this study , we cloned full - length nucleotide sequences for 3 previously unknown o. furnacalis ppos ( ofppo1a , ofppo1b , and ofppo3 ) together with ofppo2 , which had been reported previously .
we investigated the expression profiles of these 4 ppos and performed the recombinant expression using the prokaryotic expression system .
the three previously undocumented full - length cdna sequences for o. furnacalis ppos encode polypeptides with ~700 amino acid residues and apparent molecular weight of ~80 kda . as described in other insects [ 41 , 47 ] , the conceptual o. furnacalis ppo proteins also contain four conserved regions including two possible copper binding sites , one thiol ester - like motif and one common c - terminal end ( figures 13 ) .
the copper binding sites with six absolutely conserved histidine residues are common in all arthropod pos and other closely related proteins such as arthropod hemocyanins .
o. furnacalis ppos are potentially responsible for oxygen transport and melanization process due to the presence of these two binding sites .
the high similarity and the shared conserved domains of o. furnacalis ppos and arthropod ppos infer that the identified o. furnacalis ppos in this study are members of the po family .
in addition to the structurally necessary domains and motifs mentioned above , there are other two aspects worthy of note in o. furnacalis ppos .
firstly , no typical secretion signal peptide was predicted at the n - terminal region of the deduced o. furnacalis ppo1a , ppo1b , and ppo3 ( figures 1 and 2 ) .
this is also consistent with the case in o. furnacalis ppo2 and other insect ppos excluding venom ppo in the parasitoid wasp , pimpla hypochondriaca [ 11 , 19 , 49 ] . in d. melanogaster
, ppo was demonstrated to be released by the rupture of crystal cells . in other arthropods , there are possibly other ways to release ppo than by cell rupture [ 11 , 50 ] .
so far , it is unclear whether and how o. furnacalis ppos are released into the extracellular milieu .
secondly , the released ppo exists as zymogen in the hemolymph and must be activated by proteolytic cleavage [ 11 , 20 ] .
the presumed cleavage and activation sites of 4 o. furnacalis ppos were predicted between arg and phe in ofppo1a , arg and phe in ofppo1b , arg and phe in ofppo2 , and arg and phe in ofppo3 , as previously reported [ 13 , 16 , 46 ] . in h. diomphalia ,
hdppo was cleaved at the conserved bond arg - phe , followed by the second cleavage at arg - ala [ 23 , 24 ] . in the housefly musca domestica
the arg - ala bond in hdppo was identified at the common position in ofppo1a and ofppo1b , but not in ofppo2 and ofppo3 .
the arg - glu bond in mdppo was consistently present in o. furnacalis ppos except for ofppo3 with arg - thr instead ( figure 3(a ) ) .
we have determined two serine proteases , sp13 and sp105 , which functioned as prophenoloxidase - activating proteases to cleave and activate ofppo2 .
it is also unclear whether or not there exist other possible cleavage sites other than the typical arg - phe bond .
insect pos are artificially divided into tyrosinase - type pos and laccase - type pos in some reports : the former can hydroxylate monophenols to o - diphenols ( ec 1.14.18.1 ) and then oxidize the o - diphenols to quinones ( ec 1.10.3.1 ) , but it can not oxidize p - diphenols ; the latter lack the monophenol monooxygenase activity but can oxidize both o- and p - diphenols ( ec 1.10.3.2 ) [ 53 , 54 ] .
a phylogenetic analysis of the 4 o. furnacalis ppos with insect tyrosinase - type and laccase - type pos revealed two distinct clades with 100% bootstrap support .
all 4 o. furnacalis ppos fell inside the cluster of tyrosinase - type pos ( figure s2 ) .
this suggests that the identified o. furnacalis ppos are orthologous to tyrosinases rather than laccases .
the precise classification of o. furnacalis ppos can not be determined until their activities toward monophenols and p - diphenols are analyzed .
furthermore , the phylogenetic relationship among o. furnacalis ppos and other arthropod tyrosinase - type pos was proposed in this work .
o. furnacalis ppo1a and ppo1b were clustered in one lepidopteran ppo group while ppo2 and ppo3 were in the other lepidopteran ppo group ( figure 4 ) .
it suggests that lepidopteran ppo genes including o. furnacalis ppos may have undergone duplication and divergence during evolution .
it is of particular interest that up to 4 o. furnacalis ppo sequences are identified in this study since only two ppo genes have been reported in most lepidopteran species [ 13 , 16 ] .
these 4 o. furnacalis ppos were differentially expressed with respect to developmental stages , tissues , or induced conditions ( figure 5 ) .
even ppo1a and ppo1b , which are 86.82% identical in deduced amino acid sequences , also exhibited distinct expression patterns .
for example , ppo1a mrnas were detected in all tested tissues including head , gut , hemocytes , and fat bodies while ofppo1b transcripts were barely detectable in gut and fat bodies ( figure 5(b ) ) . moreover
, recombinant ofppo1b , ofppo2 , and ofppo3 could be produced successfully in prokaryotic expression system and be activated by ethanol .
three ppo genes were also identified in the swallowtail butterfly , papilio xuthus ( figure 4 ) .
therefore , we infer that all identified ppos indeed exist and potentially perform different functions in o. furnacalis , although we currently do not know why o. furnacalis possesses more ppo genes than other lepidopterans . explanations for the presence of 4 ppo sequences will be possible only when more data on po function in o. furnacalis are obtained . obtaining the recombinant ppo proteins in vitro in this study was just the first step to this aim .
the 3 o. furnacalis ppos expressed in e. coli were observed to have obvious enzyme activities after activation by ethanol ( figure 6(c ) ) . in order to potentially increase the solubility
, we also tried to obtain ppo heterodimer by performing the coexpression , but failed possibly due to plasmid instability or incompatibility ( figure s3 ) . in future work
, we will attempt to produce the recombinant ppos with higher activity and then investigate their activation mechanisms and detailed functions .
Output:
| insect phenoloxidase ( po ) belongs to the type 3 copper protein family and possesses oxidoreductase activities .
po is typically synthesized as a zymogen called prophenoloxidase ( ppo ) and requires the proteolytic activation to function .
we here cloned full - length cdna for 3 previously unidentified ppos , which we named ofppo1a , ofppo1b , and ofppo3 , from asian corn borer , ostrinia furnacalis ( gune ) , in addition to the previously known ofppo2 .
these conceptual ppos and ofppo2 all contain two common copper - binding regions , two potential proteolytic activation sites , a plausible thiol - ester site , and a conserved c - terminal region but lack a secretion signal peptide sequence at the n - terminus .
o. furnacalis ppos were highly similar to other insect ppos ( 42% to 79% identity ) and clustered well with other lepidopteran ppos .
rt - pcr assay showed the transcripts of the 4 ofppos were all detected at the highest level in hemocytes and at the increased amounts after exposure to infection by bacteria and fungi .
additionally , we established an escherichia coli ( e. coli ) expression system to produce recombinant o. furnacalis ppo proteins for future use in investigating their functions
. these insights could provide valuable information for better understanding the activation and functioning mechanisms of o. furnacalis ppos . |
PubmedSumm118780 | ***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 women , cancer of the breast is one of the most common incident cancer and cause of death from cancer.(1 ) anthropometric factors of weight , height , and body mass index ( bmi ) have been associated with breast cancer risk.(23 ) obesity leads to increased levels of fat tissue in the body that can store toxins and can serve as a continuous source of carcinogens.(4 ) body fat is an important locus of endogenous estrogen production and storage , and hence , could increase the risk of breast cancer.(5 ) there is considerable evidence that free estrogen levels are raised in obese women , especially in those with abdominal ( visceral ) obesity.(6 ) also , there is an increase in the bioavailable estrogen fraction which may promote tumor growth , either directly or by modulating steroid activity and has been implicated as a risk factor for breast cancer.(713 ) though a large number of women are affected with breast cancer , there is paucity of data on the association of anthropometry with breast cancer in the indian population .
hence , we conducted a hospital - based case - control study to identify the association of overweight and obesity with breast cancer .
the present study was a hospital - based matched case - control study conducted in the year 20012003 .
three hundred and twenty newly diagnosed breast cancer patients ( all consecutive cases ) from the out - patient and hospital admissions of the departments of surgery / surgical oncology at the all india institute of medical sciences , constituted the study population .
the criteria for selection of the patients was i ) they should be proven cases of breast cancer by histopathology / cytopathology ; ii ) they should have not undergone any treatment specific for breast cancer ; iii ) they should not have suffered from any major chronic illness in the past , before the diagnosis of breast cancer so as to change their dietary pattern ; iv ) they should not have taken long course of any vitamin or mineral supplements during the last one year ; and v ) they should not be on corticosteroid therapy or suffering from hepatic disorders / severe malnutrition .
three hundred and twenty normal healthy individuals accompanying the patients in the department of gastroenterology , medicine and surgery at all india institute of medical sciences , new delhi , and at comprehensive rural health services project at ballabgarh hospital , faridabad , haryana , constituted the control group .
the subjects in the control group were matched individually with the patients for their age 2 years and socioeconomic status .
the criteria for selection of the controls was i ) the attendants of patients who did not suffer from any major illness in the past ; ii ) they should not have taken long course of any vitamin or mineral supplements during the last one year ; and iii ) they should not be on corticosteroid therapy or suffering from hepatic disorders or severe malnutrition .
the study was ethically approved by the ethics committee of all india institute of medical sciences , new delhi .
all the investigations to be performed were explained to the subjects and those who consented for participation were included in the study .
, semistructured questionnaire was administered to each individual to collect information on identification data and sociodemographic profile .
anthropometric measurements of weight and height were recorded utilizing the standard equipments and methodology.(14 ) weight was recorded using seca electronic weighing scale , to the nearest 100 g. the subjects were asked to be barefoot and with light clothing .
she was asked to stand straight on the electronic weighing scale and the weight displayed on the screen was recorded .
the subject was asked to stand straight with head position such that frankfurt plane is horizontal , feet together , knees , heels and shoulder blades straight , arms hanging loosely on either side with palms facing the thighs .
accordingly , the nutritional status was defined as follows : i ) bmi 2024.9 ( normal ) ; ii ) bmi 2529.9 ( overweight ) ; and iii ) bmi 30 ( obesity ) . the mid upper arm circumference ( muac )
the left mid upper arm circumference was measured , while hanging the arm freely and gently placing the tape round the limb at its midpoint.(14 ) the paired
t test was utilized to compare the mean anthropometric values between breast cancer patients and controls .
the univariate logistic regression analysis was also carried out to calculate the odds ratios and the confidence intervals .
a total of 320 breast cancer patients and 320 matched controls were enrolled for the present study .
the mean age of the patients and controls was 45.5 and 40.98 years , respectively .
all the patients were married and about 95.9% of the patients and 95.6% of the controls were housewives . nearly 37.2 and 35.9% of the patients and controls were illiterate , respectively .
forty six percent of the patients and 36.3% of the controls belonged to lower middle socioeconomic status .
the distribution of breast cancer patients and controls according to their mean anthropometric measurements is depicted in table 1 .
it was observed that the patients had a statistically higher mean weight ( 59.75 10.92 kg ) as compared to the controls ( 56.44 11.24 kg ) .
the mean bmi and muac were also found to be significantly higher in patients as compared to the controls .
mean anthropometric measurements of breast cancer patients and controls it was observed that 13.4% of the patients and 6.6% of the controls were obese according to their bmi .
it was observed that the risk of breast cancer increased with increasing levels of bmi .
overweight and obese women had or of 1.06 ( 95% ci : 0.761.47 ) and 2.27 ( 95% ci : 1.284.01 ) as compared to women with normal weight [ table 2 ] .
the breast cancer patients had a statistically higher mean weight , bmi , and muac as compared to the controls .
obesity and weight gain are positively associated with serum concentrations of endogenous estrogens leading to moderate elevations in both the incidence and mortality from the disease , thus affecting breast cancer growth and metastasis.(1516 ) a study conducted in usa revealed that the adjusted or for women weighing over 81 kg relative to women weighing under 63 kg was 2.1 ; 95% ci : 1.33.2.(17 ) an earlier case control study conducted in ireland revealed that bmi was significantly higher in cases ( 26.2 kg / m ) as compared to controls ( 24.5 kg / m ) ( p < 0.05).(18 ) it was observed that the risk of breast cancer increased with increasing levels of bmi .
overweight and obese women had or of 1.06 ( 95% ci : 0.761.47 ) and 2.27 ( 95% ci : 1.284.01 ) as compared to women with normal weight . an earlier case - control study conducted in usa revealed that the risk of breast cancer increased with increasing levels of bmi .
overweight and obese women had or of 1.14 ( 95% ci : 0.961.36 ) and 1.22 ( 95% ci : 0.991.50 ) as compared to women at normal weight.(19 ) meta analysis of case control data from countries at high , moderate , and low risk for breast cancer demonstrated that breast cancer incidence rates consistently increased with adiposity among both premenopausal and post menopausal women.(20 ) similar results have been shown by other studies.(2127 ) the results of the present study revealed a strong association of overweight and obesity with breast cancer in the indian population .
hence , weight control may be a modifiable risk factor for breast cancer prevention and thus may have significant public health impact in women .
Output:
| background : in women , cancer of the breast is one of the most common incident cancer and cause of death from cancer .
anthropometric factors of weight , height , and body mass index ( bmi ) have been associated with breast cancer risk.objectives:to study the association of overweight and obesity with breast cancer in india.materials and methods : a hospital - based matched case - control study was conducted .
three hundred and twenty newly diagnosed breast cancer patients and three hundred and twenty normal healthy individuals constituted the study population .
the subjects in the control group were matched individually with the patients for their age 2 years and socioeconomic status .
anthropometric measurements of weight and height were recorded utilizing the standard equipments and methodology . the paired
t test and univariate logistic regression analysis were carried out.results:it was observed that the patients had a statistically higher mean weight , body mass index , and mid upper arm circumference as compared to the controls .
it was observed that the risk of breast cancer increased with increasing levels of bmi .
overweight and obese women had odd 's redio of 1.06 and 2.27 , respectively , as compared to women with normal weight.conclusions:the results of the present study revealed a strong association of overweight and obesity with breast cancer in the indian population . |
PubmedSumm118781 | ***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: vitamin d is a fat - soluble vitamin obtained by the human body in two ways , through dietary intake mainly from fatty fish , eggs and fortified food and through endogenous production in the skin after ultraviolet - b exposure .
rising evidence suggests that vitamin d deficiency is associated with a higher risk of preeclampsia , growth retardation , multiple sclerosis , schizophrenia , diabetes and asthma ( scholl & chen , 2009 ) .
there is currently no consensus what the correct reference values for serum vitamin d in pregnancy are , whether these reference values should be the same for all ethnic populations nor what the physiologic changes during pregnancy are .
immigrants in northern countries , especially when they are dark skinned and/or wear total body covering clothes ( e.g. the traditional muslim clothing ) , are more prone to vitamin d deficiency , particularly in pregnancy ( mccullough , 2007 ; van der meer et al . , 2006 ) .
we studied the prevalence of vitamin d deficiency in maternal and umbilical cord blood in a pregnant population of mixed ethnic origin .
this was a descriptive single center study performed at antwerp university hospital ( edegem , belgium ) . from april 1st
to may 31st 2011 all term pregnant women presenting with spontaneous term labour were asked to have a blood sample drawn for vitamin d. a venous maternal serum sample and a sample form the umbilical vein at delivery were collected .
the study was approved by the local ethics committee and all patients signed a written informed consent .
term pregnancy was defined as from 37 weeks on ; complications such as diabetes , hypertension , fetal growth retardation or any other maternal disorder necessitating special care during pregnancy ( including bariatric surgery and a previous baby with a congenital malformation ) were excluded .
a short food questionnaire was presented including questions on previous pregnancy and delivery , birth weight of previous children , previous surgery , congenital anomalies in the family , use of vitamin supplements during pregnancy , any medication , eating eggs , meat , fish , vegetables , fruits and using alcoholic beverages .
patients were also asked for their self - identified ethnic group : autochthonous belgian , moroccan , turkish , central african , western european ( other than belgian ) , ( east)-asian and other . 25-hydroxy vitamin d was analysed with the modular analytics e170 ( roche diagnostics , belgium ) , the measurement area used was 4 to 100 ng / ml . a serum level below 20 ng / ml was considered vitamin b12 deficiency ( iom , 2010 ) .
spearman s rank correlation analysis was used to check for correlation between maternal and umbilical cord values .
linear regression was performed to evaluate other factors such as nutrition and use of supplements .
of 110 women included in the study , 90 ( 81.8% ) completed the questionnaire . there were 54 ( 48.8% ) primiparous and 56 ( 51.2% ) multiparous women .
the only brand used was omnibionta pronatal ( merck , belgium ) 10 microgram ( 400 iu ) of vitamin d. there were 56 ( 51% ) autochthonous belgian women , 26 ( 24% ) moroccan , 8 ( 7% ) asian , 8 ( 7% ) central african , 10 ( 9% ) western european other than belgian , and only 2 ( 2% ) turkish .
maternal serum 25-hydroxy vitamin d was available for 94 ( 85.5% ) of women ; missing samples were almost all from women having signed the informed consent , but whose delivery was completed before blood samples were taken , mainly during night time .
mean serum 25-hydroxy vitamin d was 16.6 ng / ml ( standard deviation 12.7 ng / ml , minimum 4 ng / ml , maximum 64 ng / ml ) .
vitamin d deficiency was noted in 62 ( 65.9% ) of women . for the women with vitamin d deficiency 28 ( 45.2% of those deficient for vitamin d ) was autochthonous belgian , 20 ( 32.3% ) moroccan , 6 asian ( 9.7% ) , 4 central african ( 6.4% ) , 2 western european other than belgian ( 3.2% ) and 2 turkish ( 3.2% ) .
this means that for belgian mothers 50% , for moroccan 76.9% , for asian 75% , for central african 50% , for other european 20% and for turkish women 100% was vitamin d deficient .
mean 25-hydroxy vitamin d was 20.5 ng / ml ( standard deviation 10.1 ng / ml , maximum 35 ng / ml , minimum 4 ng / ml ) . in 42 cases ( 50% )
the level was below 20 ng / ml . correlation between maternal and umbilical cord levels was rather strong ( spearman s correlation coefficient r = 0.91 ) .
umbical cord deficiency was present in 44 belgian mothers ( 52.4% of deficiencies ; 78.6% of belgian mothers ) , 24 moroccan ( 28.6% of deficiencies , 92.3% of moroccan women ) , 4 central african ( 4.7% and 50.0% respectively ) , 8 asian ( 9.5% and 100% of asian samples ) , 2 other european ( 2.4% and 20.0% respectively ) and 2 turkish ( 2.4% , including 100% of turkish babies ) . the only significant factor ( except ethnicity ) in the linear regression determining maternal serum levels for 25 hydroxy vitamin d was eating eggs : the more per week the less deficiency ( eating 1 to 2 eggs per week ; p = 0.025 , eating 3 to 4 eggs per week : p = 0.016 ) . using a vitamin supplement
despite the fact that the majority of women in our sample was using vitamin supplementation , deficiency for vitamin d was present in the majority . this can be due both to biologic factors such as interference with food or absorption , but it can also be due to bias in reporting if women who report using vitamins fail to effectively take them .
the brand used in our population , the most popular one , sold over the counter to pregnant women in belgium , contains too low an amount of vitamin d to counter deficiencies , but the optimal dose and timing continue to be a matter of dispute ( hovdenak et al . , 2012 ) .
another possibility is that the available criteria for vitamin d deficiency , as we and others have used , are not reflecting true vitamin d deficiency .
vitamin d deficiency is clearly more frequent in women from north african ( moroccan ) , central african and asian descent .
we have previously described traditional clothing with a veil covering the face to be an independent risk factor for vitamin d deficiency ( vercruyssen et al . , 2012 ) , probably due to lower skin to sun contact . as all of our measurements have been performed in a short period during spring , a seasonal influence between groups has been excluded . recently
the amount of air pollution at the mother s home address was identified as another determining factor , but for this we have no data in our study ( baz et al . ,
a recent review has summarized the impact of low vitamin d on pregnancy , demonstrating a correlation with preeclampsia , gestational diabetes , bacterial vaginosis and postpartum depression , which suggests a potential effect of vitamin d on several pregnancy outcomes ( christesen et al . , 2012 ) .
it should be kept in mind though that this does not mean that vitamin d supplementation would lower the incidence of the above - mentioned pregnancy complications ; published trials on supplementation have been of low quality and have only demonstrated none to borderline significant changes in outcome ( de - regil et al . , 2012 ; thorne - lyman et al . , 2012 ) .
in fact , there is as yet no sound scientific prove of any beneficial effect of vitamin d supplementation in pregnancy .
this should be kept in mind before considering systematic supplementation with vitamin d. there is no consensus on the clinically relevant values to use for defining vitamin d deficiency ; other studies have also demonstrated a very high prevalence of vitamin d deficiency in pregnant women both in northern america and western europe ( van der meer et al . , 2006 ;
recently confusing and contradictory publications have been issued from the institute of medicine and from the endocrine society , demonstrating inadequate evidence to guide clinical management ( rosen et al . , 2012 ) . before considering interventions major and convincing studies on
the majority of women in our study had what is considered vitamin d deficiency although this was a selected low risk pregnancy group excluding preterm labour , growth retardation and hypertension .
furthermore one should consider the ethnic origin of the mother , as it seems rather inconsequent to consider almost all north and central african women , having uncomplicated pregnancies and deliveries , as suffering from hypovitaminosis d ( van noord & berghout , 2012 ) .
women having an uncomplicated pregnancy and delivery in antwerp , belgium , frequently show vitamin d deficiency which was correlated with lower umbilical cord vitamin d levels .
the prevalence of low vitamin d levels is highest in women from north african , central african and asian descent and is not influenced by the intake of the available over the counter vitamin supplements .
we question the appropriateness of a vitamin d deficiency cut - off value of 20 ng / ml for a multiethnic population in western europe .
Output:
| objective : to describe the status of vitamin d levels in maternal and umbilical cord blood in term pregnant woman in a mixed ethnic population in an inner - city european maternity.methods : a single centre prospective cohort descriptive study including all uncomplicated singleton term pregnancies from april 1 , 2011 until may 31 , 2011 .
plasma 25-hydroxy vitamin d level was determined in maternal and umbilical cord blood and data on age , previous obstetric history , ethnicity , nutritional intake and use of vitamin supplements were registered.results : complete data were collected in 94 patients . mean maternal serum vitamin d was 16.6 ng / ml . using a cut - off of 20 ng / ml ,
66% of women were classified as deficient .
deficiency was present in all ethnic groups , but lower levels were noted in north - african , central - african and asian women . a strong correlation between maternal and umbilical cord levels was noted ( r = 0.91 ) .
number of previous pregnancies and intake of supplements had no influence.conclusion : the majority of low risk pregnant women showed vitamin d deficiency which was strongly correlated with umbilical cord levels .
the prevalence was highest in the immigrant non - european population and was not influenced by intake of vitamin supplements .
it can therefore be questioned whether the proposed cut - off values are appropriate . |
PubmedSumm118782 | ***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: toxic epidermal necrolysis ( ten ) is a severe and life - threatening condition involving skin and mucous membrane .
the drugs most commonly causing ten are sulfonamides , penicillins , other antibiotics , non - steroidal anti - inflammatory drugs , anti convulsants , etc .
these drugs reaction are more common in individuals having human immunodeficiency virus ( hiv ) infection / aids than the general population .
fluconazole , an antifungal drug of the azole group , is frequently used for management of candidial infections , coccidiodal meningitis , cryptococcal meningitis , and in empiric treatment of critically ill hiv - infected patients .
the usual side effects of fluconazole mentioned in the literature are mild like nausea , vomiting , headache , elevation of hepatic transaminases , etc .
ten / stevens - johnson syndrome ( sjs ) caused by fluconazole in immunesuppressed patients is very rare and reported in only three reports previously.[46 ] we present an additional case of this type in view of lack of such reports in the indian literature .
a 28 year old male patient , taking anti - tuberculosis treatment for last 3 months for pulmonary tuberculosis , now presented with oral thrush .
he was not married but gave history of multiple unprotected roadside sexes . on examination ,
there was pallor and extensive oral thrush over tongue extending up to tonsil , and posterior pharyngeal wall .
other systemic examination revealed no abnormality . in view of high risk behavior and the presence of oral thrush
, his sera were subjected to hiv1 and hiv2 testing that turned out to be reactive . his other investigations revealed hemoglobin 8 g% with normal leukocyte count , differential count , fasting blood sugar , liver function test , renal function test , etc .
a skiagram chest showed regression of pulmonary infiltrates in comparison to previous chest x - ray .
the antituberculosis treatment was continued and oral fluconazole 150 mg daily was started with povidone iodine gargles . on the second day of fluconazole therapy ,
the patient developed generalized body ache along with pruritic rash over face , trunk , and extremities .
the rashes first appeared over the trunk and then spread to involve extremities and face .
the lesions subsequently ruptured with sloughing of large sheets of skin , leaving behind erythematous areas involving more than 70% of the body surface area .
based on clinical course following fluconazole therapy , a diagnosis of fluconazole - induced ten ( naranjo score 6 ) was made .
laboratory investigations this time revealed normal total leukocyte counts , but slight elevation of liver enzyme ( alt50 iu / l , ast64 iu / l ) .
the patient was managed conservatively with local soothing agents , analgesics , azithromycin , antihistaminics , and eye care with adequate parenteral hydration . the patient improved with above therapy .
ten and sjs are acute and life - threatening disorder of unclear pathophysiology , characterized by epidermal necrosis , erosions of mucous membrane , and detachment of epidermis with constitutional symptoms . cases having less than 10% of epidermis involvement are designated as sjs , while those having 30% epidermis involvement are labeled as ten .
cases with between 10% and 30% involved areas are defined as overlap sjs ten .
the estimated incidence of ten is about 1.171.89 cases per million inhabitants per year in observational studies .
the risk of ten is much higher in individuals having hiv infection and other autoimmune disorders.[1012 ] ten is almost always induced by drugs .
although a long list of drugs have been implicated as a cause for ten , the drugs commonly associated with ten are sulfonamides , anticonvulsants , allopurinol , non - steroidal anti - inflammatory drugs , etc .
ten / sjs induced by fluconazole is very rare and till date only three cases have been reported .
the very first case involved a 30-year - old gay , hiv positive man developing sjs following fluconazole therapy for oral candidiasis .
the second case involved a 33-year - old hiv positive male who developed ten following treatment with fluconazole for dysphagia and recurrent oral thrush .
the third one was a 52-year - old immunosuppressive woman developing ten after fluconazole for the treatment of esophageal candidasis .
the exact mechanism for drug - induced ten is unclear but immunological mechanisms , reactive drug metabolites and interactions between the two have been proposed .
multiple prior cutaneous drug reaction or prior reaction to a specific drug is also found to be a risk factor for ten in hiv infected individuals .
the higher incidence of ten among hiv - infected patients may also be related to glutathione deficiency .
b cells which are defectively activated to secrete immunoglobulins leading to circulatory immune complexes and autoimmune phenomenon .
all these mechanism makes hiv - infected individuals more vulnerable to ten due to drugs .
therefore in all patients with drug - induced ten , an underlying hiv infection should always be ruled out . to our knowledge
this is the fourth reported case and probably be the first one in india of ten secondary to fluconazole in a patient having hiv infection .
Output:
| stevens - johnson syndrome and toxic epidermal necrolysis ( ten ) are rare but serious dermatologic disorders .
these grave conditions present as medical emergency , requiring prompt diagnosis and management .
these are often drug induced and various groups of drugs , such as sulfa drugs , nsaids , etc .
, have been implicated as to cause ten .
fluconazole is a commonly used drug with mild side effects .
ten caused by fluconazole is rare , and till now only few cases have been reported in the literature .
we present a case of ten in a human immunodeficiency virus infected man following fluconazole therapy in view of its rare occurrence . |
PubmedSumm118783 | ***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: sample size was computed using this formula.n=(z1-/2)2*p*(1-p)d2
the subjects were selected by nonprobability method from akhavan and saba treatment and rehabilitation clinic , tehran , iran . written informed consents were taken and the study was approved by the ethics committee of ethnics in the university of social welfare and rehabilitation sciences .
diagnoses were established according to the diagnostic and statistical manual ( dsm)-iv - tr criteria and only nonpsychotic major depressive disorder was included .
patients were between 18 and 65 years of age and had to be free from psychiatric drugs at least four weeks before their entry into this study .
exclusion criteria were as follows : lactation or pregnancy , drug abuse ( if a patient had a history of drug abuse at least four months prior to the study , he / she was excluded from the study ) , suicidal ideation , co - morbid severe disorders .
the study consisted of one hundred and four research subjects suffering from major depressive disorder ( male : 26 ; female : 78 ; 18 - 65 years old ) .
of the subjects , 25 came back to drug usage , 20 abundant their treatment , and 41 could not follow the therapeutic process systematically , and were excluded from the study.the treatment regime at level 1 aimed to evaluate outcome of treatment with the antidepressant drug citalopram ( minimal dose : 20 mg / d ) . to reduce the risk of inadequate dosing , and to ensure that patients who progressed to the next level of the treatment were truly resistant to the level 1 treatment , the study was carried out with a desired end point after 14 weeks of treatment which is regarded as a long enough period for adjusting an optimal dosage and evaluating the corresponding effects . if deemed necessary , patients were , however , allowed to proceed into level 2 before 4 weeks of the treatment ( 40 - 60mg / d ) , and were included in this analysis if they had received at least 8 weeks of treatment with citalopram .
concomitant psychotropic drug that patients used was alprazolam up to 2 mg / d for sleep ( until 15 days and then tapered ) . in the next visit ( 3 - 4 weeks later ) , depression symptoms and the recovery rates were studied . after examining the mental state of each patient ,
adherence was monitored by weekly self - reports which corrected by a psychiatrist , and plasma levels of antidepressants were measured at weeks 4 and 8 .
adverse effects of medication were measured using the uku side - effect rating scale ( 29 ) and self - report antidepressant side - effect checklist ( 30 ) .
to determine httlpr genotypes , genomic dna was extracted from whole blood by salting out method ( 31 ) and polymerase chain reaction ( pcr ) amplification to generate the 487- or 523- base pair fragments corresponding to the s and l 5-httlpr alleles , respectively .
amplification of genomic dna was performed using 50 ng dna , 0.25 mm of each primer ( forward : 5'-ggc gtt gcc gct ctg aat c-3 ' and reverse : 5'-gag gga ctg agc tgg aca acc ac-3 ' ) ( 32 ) reaction conditions were 1x pcr buffer ; 1x q - solution ( qiagen ) , 0.2 mm dntps , 2 mm mgcl2 ( total concentration including from buffer ) ; 20 ng/l of each primer and a total of 10 ng of dna in a 10-l reaction . to obtain the best sharp bands ,
cycling conditions were 95c for 3 min ; 35 cycles at 94c for 1 min , 58c for 1 min , 72c for 45 s , 72c for 5 min , and hold on 4c .
the labeled pcr products were separated on 2% agarose gel to differentiate the l ( 523bp ) and s ( 487bp ) variants .
the analysis was performed on a knaver hplc system ( smart model ) , consisting a uv detector and an injector with 100l loop .
chromatographic separation was achieved isocratically at room temperature on a spherisorb ods2 column ( 250 mm4 mm , 5 m particle size ( lkb , bromma , sweden ) .
the plasma level of all the patient 's citalopram were in the therapeutic range ( 30 - 130 ng / ml ) .
researchers who were blind to the clinical scores of depression performed quantification of plasma levels and genotyping .
the clinician - rated 21 items of beck depression inventory was used to measure the treatment response at each treatment visit and at the end of the treatment period of up to 12 weeks . in the categorized outcome definition ,
remitters were defined as having a beck score 10 at endpoint of the level 1 treatment , whereas non - remitters still had a score 10 at the last visit as long as they were not classified as intolerant of the medication . in a parallel analysis , response was defined as a 50% reduction of beck score at the last treatment visit and non - response as less than a 40% reduction . in order to minimize the risk for misclassification , individuals who received scores between these ranges or had less than 6 weeks of treatment were excluded from the respective analysis .
after such exclusions , a total of 104 individuals were eligible for the treatment - response study when response was the outcome .
clinicians were blind to the plasma levels and genotype of each patient till the end of the study . at first , we used chi - square to test the significance of association between sex , genotype and treatment .
then , we used logistic regression to model the relationship between the odds of treatment and sex and genotype .
two independent variables were entered into a logistic model simultaneously to assess the predictive ability of each variable while controlling for all other variables . the interaction term between sex and genotype
the hosmer and lemeshow test was used in this model to evaluate the significance of improved port with introduction of additional variables .
sample size was computed using this formula.n=(z1-/2)2*p*(1-p)d2
the subjects were selected by nonprobability method from akhavan and saba treatment and rehabilitation clinic , tehran , iran . written informed consents were taken and the study was approved by the ethics committee of ethnics in the university of social welfare and rehabilitation sciences .
diagnoses were established according to the diagnostic and statistical manual ( dsm)-iv - tr criteria and only nonpsychotic major depressive disorder was included .
patients were between 18 and 65 years of age and had to be free from psychiatric drugs at least four weeks before their entry into this study .
exclusion criteria were as follows : lactation or pregnancy , drug abuse ( if a patient had a history of drug abuse at least four months prior to the study , he / she was excluded from the study ) , suicidal ideation , co - morbid severe disorders .
the study consisted of one hundred and four research subjects suffering from major depressive disorder ( male : 26 ; female : 78 ; 18 - 65 years old ) .
of the subjects , 25 came back to drug usage , 20 abundant their treatment , and 41 could not follow the therapeutic process systematically , and were excluded from the study.the treatment regime at level 1 aimed to evaluate outcome of treatment with the antidepressant drug citalopram ( minimal dose : 20 mg / d ) . to reduce the risk of inadequate dosing , and to ensure that patients who progressed to the next level of the treatment were truly resistant to the level 1 treatment , the study was carried out with a desired end point after 14 weeks of treatment which is regarded as a long enough period for adjusting an optimal dosage and evaluating the corresponding effects . if deemed necessary , patients were , however , allowed to proceed into level 2 before 4 weeks of the treatment ( 40 - 60mg / d ) , and were included in this analysis if they had received at least 8 weeks of treatment with citalopram .
concomitant psychotropic drug that patients used was alprazolam up to 2 mg / d for sleep ( until 15 days and then tapered ) . in the next visit ( 3 - 4 weeks later ) , depression symptoms and the recovery rates were studied .
after examining the mental state of each patient , the severity of depression was assessed with beck depression inventory .
adherence was monitored by weekly self - reports which corrected by a psychiatrist , and plasma levels of antidepressants were measured at weeks 4 and 8 .
adverse effects of medication were measured using the uku side - effect rating scale ( 29 ) and self - report antidepressant side - effect checklist ( 30 ) .
to determine httlpr genotypes , genomic dna was extracted from whole blood by salting out method ( 31 ) and polymerase chain reaction ( pcr ) amplification to generate the 487- or 523- base pair fragments corresponding to the s and l 5-httlpr alleles , respectively .
amplification of genomic dna was performed using 50 ng dna , 0.25 mm of each primer ( forward : 5'-ggc gtt gcc gct ctg aat c-3 ' and reverse : 5'-gag gga ctg agc tgg aca acc ac-3 ' ) ( 32 ) reaction conditions were 1x pcr buffer ; 1x q - solution ( qiagen ) , 0.2 mm dntps , 2 mm mgcl2 ( total concentration including from buffer ) ; 20 ng/l of each primer and a total of 10 ng of dna in a 10-l reaction . to obtain the best sharp bands ,
cycling conditions were 95c for 3 min ; 35 cycles at 94c for 1 min , 58c for 1 min , 72c for 45 s , 72c for 5 min , and hold on 4c .
the labeled pcr products were separated on 2% agarose gel to differentiate the l ( 523bp ) and s ( 487bp ) variants .
the analysis was performed on a knaver hplc system ( smart model ) , consisting a uv detector and an injector with 100l loop .
chromatographic separation was achieved isocratically at room temperature on a spherisorb ods2 column ( 250 mm4 mm , 5 m particle size ( lkb , bromma , sweden ) .
the plasma level of all the patient 's citalopram were in the therapeutic range ( 30 - 130 ng / ml ) .
researchers who were blind to the clinical scores of depression performed quantification of plasma levels and genotyping . the clinician - rated 21 items of beck depression inventory was used to measure the treatment response at each treatment visit and at the end of the treatment period of up to 12 weeks . in the categorized outcome definition
, remitters were defined as having a beck score 10 at endpoint of the level 1 treatment , whereas non - remitters still had a score 10 at the last visit as long as they were not classified as intolerant of the medication . in a parallel analysis ,
response was defined as a 50% reduction of beck score at the last treatment visit and non - response as less than a 40% reduction . in order to minimize the risk for misclassification , individuals who received scores between these ranges or had less than 6 weeks of treatment were excluded from the respective analysis .
after such exclusions , a total of 104 individuals were eligible for the treatment - response study when response was the outcome .
clinicians were blind to the plasma levels and genotype of each patient till the end of the study .
at first , we used chi - square to test the significance of association between sex , genotype and treatment .
then , we used logistic regression to model the relationship between the odds of treatment and sex and genotype .
two independent variables were entered into a logistic model simultaneously to assess the predictive ability of each variable while controlling for all other variables . the interaction term between sex and genotype
the hosmer and lemeshow test was used in this model to evaluate the significance of improved port with introduction of additional variables .
of the one hundred and four participants , 36 ( 34.6% ) were homozygous for the l allele ( l / l genotype ) , 34 ( 32.7% ) were heterozygous ( l / s genotype ) , and 34 patients ( 32.7% ) were homozygous for the s allele ( s / s genotype ) . according to our study , carriers of the l allele , either homozygous of l / l or heterozygous of l / s , had a better and faster response to the treatment with citalopram .
on the other hand , gender should also be considered when examining the genetic effects of 5-httlpr on psychological outcomes ( 33 ) .
significant main effects in participants treated with citalopram qualified the interaction effects especially in men .
we found a statistically significant association between sex and treatment ; citalopram response odds ratio was 4.22 ( 95 percent ci : 1.29 - 13.76 ) for men compared with women ( table 3 ) .
an association was observed between l / s and treatment . using s / s as the reference group , treatment odds ratios for l / s and l / l were 3.90 ( 95 percent ci : 1.29- 11.80 ) and 1.90 ( 95 percent ci : 0.72 - 5.08 ) , respectively ( table 3 ) . among patients treated with citalopram , those homozygous for the short allele had significantly worse outcome than long - allele carriers , and this effect of the 5-httlpr genotype was more considerable among males treated with citalopram but was absent among females treated with citalopram ( table 1 ) .
odds ratio for males genotype ( ( l / l or l / s ) / ss ) is equal to 0.074 with 95% confidence interval ( 0.006 , 0.911 ) , whereas odds ratio for females genotype ( ( l / l or l / s ) / ss ) was equal to 0.516 , with 95% confidence interval ( 0.201 , 1.327 ) .
characteristics of the 65 analytical samples by sex , genotype and treatment obviously , there is a huge difference between female 's and male 's genotype in response to antidepressant treatment . as it is shown in table 2 , overall response of individuals with the l / l genotype and l / s genotype ( 70% ) , confirming a dominant effect of the l allele compared with the response of homozygotes of the s allele ( 47.1% ) .
the statistical analyses proved the strong correlation between the presence of the l allele and better response to antidepressant drug citalopram , ( p = 0.023 , and pearson chi - square test statistic = 5.139 ) .
there has been much recent interest in the use of genetic variants for the prediction of response to medication treatments ( 34 ) , which is so important for the psychopharmacologic treatment of psychiatric disorders ( 20 ) . in this study of iranian sample population for the slc6a4 promoter polymorphism
, we observed that specifically male carriers of the 5-httlpr long allele showed a better response to citalopram treatment than male short - allele homozygotes ( p = 0.047 ) , whereas such affect is absent among women ( p= 0.167 ) .
the finding of this study is consistent with that of previous reports of gender specific genetic influences on serotonergic function ( 35 ) that might indicate a biological interaction between the serotonergic system and ovarian hormones . through the oestrogen alpha receptor ,
oestrogens stimulate the production of the 5-ht receptor that is involved in the regulation of serotonin release and is down regulated in response to serotonin reuptake inhibitors ( 27 ) .
it is possible that the impact of the less functional short 5-httlpr allele is moderated by the oestrogen - induced stimulatory effect on serotonin transporter expression in hormonally active women .
although this evidence shows biological plausibility to the observed 5-httlpr - gender interaction , this finding requires replication in an independent sample .
therefore , overall , the study revealed a significant correlation between carrying the l allele and better response to citalopram treatment that confirms the previous western reports ( 3639 ) , and one meta - analysis ( 23 ) , whereas it is in contrasts with a korean study ( 40 ) and some other meta - analysis ( 24 , 41 ) . adjusted odds ratios for treatment b , in the logistic analysis adjusted for another variable in the table . refers to participants with a treatment - yes .
first , most of the previous studies were gender independent , so the number of female individuals who showed poorer response to treatment with the antidepressant drug , citalopram , might modulate the results .
second , the 5-httlpr polymorphism may be in linkage disequilibrium with a functional variant that affects ssri response , and the extent of this linkage disequilibrium would be different in each of that ethnic populations .
thus , the association between 5httlpr genetic variants and ssri treatment response may be ethnicity - dependent ( 42 ) .
thirdly , this discrepancy may have resulted from differences in severity of mdd or subtypes for mdd populations enrolled in various studies , and as compared with the european american population , the l allele frequency in chinese ( 42 , 43 ) or korean ( 40 ) populations was much lower .
on the other hand , we believe that therapeutic antidepressant effect may involve the interaction of many different genes . therefore , a single gene may play only a relative role , and not be strongly associated with antidepressant response .
thus , analysis of the interactions of multiple genes implicated in the pharmacokinetics of ssris is suggested to be mentioned in future pharmacogenetic study of antidepressants , although it is unlikely that the 5-httlpr polymorphism alone will be clinically useful in predicting response to antidepressants in people with depression ( 44 ) . in summary ,
in this study it was revealed that for iranian population , male patients bearing the 5httlpr l / l or l / s genotype have a superior response to ssri treatment than s allele - carriers , supporting western reports .
Output:
| objectiveseveral studies have implicated the 5-httlpr polymorphism in treatment outcomes of selective serotonin re - uptake inhibitors in patients with major depression . the aim of this study was to examine the association between polymorphism in the serotonin transporter gene and citalopram effectiveness in iranian patients suffering from major depressive disorder ( mdd).methodsthe sample consisted of 104 patients , with fars ethnic background , who were diagnosed according to dsm - iv - tr criteria .
beck depression inventory was used to evaluate the severity of the symptoms during the follow - up , and to determine clinical response of the patients at 4th and 8th week , respectively.resultsour results showed a correlation between the genotype and response to antidepressant drug citalopram , ( odds ratios for l / s and l / l were 3.90 ( 95 percent ci : 1.29- 11.80 ) and 1.90 ( 95 percent ci : 0.72 - 5.08 ) , respectively).conclusionin conclusion , our results reveal that genetic variation of serotonin transporter is involved in clinical remission of major depressive episodes in iranian patients after citalopram treatment . |
PubmedSumm118784 | ***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 skin is the largest organ of the body there are no standardized reproducible methods for assessing skin function or severity of skin disease . during recent years
several scoring systems have been introduced to help clinical practice and clinical research on many skin diseases , which mainly compare inter - individual differences in disease activity .
the most known dermatologic tool is the psoriasis area severity index ( pasi ) , which is currently the gold standard score for the assessment of severity of psoriasis .
it combines the severity ( erythema , induration and desquamation ) and percentage of affected area . a free online application helping physicians and patients in the computation of the pasi is available as well .
vitiligo is an acquired depigmentary disorder characterized by the loss of functioning epidermal melanocytes it would be important to have accurate measurement of the size of vitiligo surface areas to assess treatment efficacy .
recently some new score systems were proposed . the vitiligo european task force ( vetf )
was proposed a system combining analysis of extent , stage of disease and disease progression .
the vitiligo area scoring index ( vasi ) is another score system offering accurate measures of disease severity indexes and treatment evaluation criteria .
nevertheless both scores are not comprehensive , have some limitations : they do not produce a constant total number with discrepancy and inter - individual variations .
reasonably it would make sense to combine the vasi with the vetf system and make a system much more similar to pasi score with constant total number and less inter - individual differences .
the purpose of this manuscript was to combine vetf and vasi system and develop a practical and standardized scoring system similar to pasi score with the aim to assess the treatment response and evaluate changes in affected area .
additionally it has a potential to be a source of any computed application for researchers who work on vitiligo patients .
vetf is a system that incorporates three components of vitiligo : extent , stage and progression of disease .
staging is based on cutaneous and hair pigmentation in vitiligo patches and divided in three stages :
stage 0 : normal pigmentationstage 1 : incomplete depigmentationstage 2 : complete depigmentation ( hair whitening less than 30% ( < 30%)stage 3 : complete depigmentation plus hair whitening more than 30% ( > 30% ) stage 0 : normal pigmentation stage 1 : incomplete depigmentation stage 2 : complete depigmentation ( hair whitening less than 30% ( < 30% ) stage 3 : complete depigmentation plus hair whitening more than 30% ( > 30% ) spreading in vetf is ( + 1 : progressive ; 0 : stable ; 1 : regressive ) .
the degree of pigmentation is estimated to the nearest of one of the following percentages : 100% - complete depigmentation , no pigment is present ; 90% - specks of pigment present ; 75% - depigmented area exceeds the pigmented area ; 50% - pigmented and depigmented areas are equal ; 25% - pigmented area exceeds depigmented area ; and 10% - only specks of depigmentation present .
the vasi for each body region is determined by the product of the area of vitiligo in hand units and the extent of depigmentation within each hand unit measured patch .
total body vasi = s all body sites [ hand units ] [ residual depigmentation ] .
vida score based on patients opinion divided in 6 stages : grading is as follows .
vida score :
+ 4 : activity of 6 weeks or less period+3 : activity of 6 weeks to 3 months+2 : activity of 3 to 6 months+1 : activity of 6 to12 months0 : stable at least for 1 year and1 : stable at least for 1 year with spontaneous repigmentation + 4 : activity of 6 weeks or less period + 3 : activity of 6 weeks to 3 months + 2 : activity of 3 to 6 months + 1 : activity of 6 to12 months 0 : stable at least for 1 year and 1 : stable at least for 1 year with spontaneous repigmentation lower vida scores indicate less activity .
benzekari et al . in 2013 demonstrated a new index ( pri ) for prediction of potential repigmentation in non - segmental vitiligo and showed that the patients with higher pri were more prone to obtain higher pigmentation .
the veti score is a new system that proposes to measure the extent of vitiligo by a numerical score and combines analysis of extensity and severity of vitiligo and produce a constant and reproducible number like pasi .
the percentage of extension involvement ( p ) evaluates using the rule of nines ( figure 1 ) already used in burn assessment .
five sites affected , head ( h ) , upper limbs ( u ) , trunk ( t ) and lower limbs ( l ) and genitalia ( g ) are separately scored by using five stages of disease tensity ( t ) :
stage 0 : normal skinstage 1 : hypopigmentation ( including trichrome and homogeneous lighter pigmentation ) ( figure 2)stage 2 : complete depigmentation with black hair and with perifollicular pigmentation ( figure 3)stage 3 : complete depigmentation with black hair and without perifollicular pigmentation ( figure 4)stage 4 : complete depigmentation with compound of white and black hair with / without perifollicular pigmentation ( figure 5)stage 5 : complete depigmentation plus significant hair whitening ( figure 6 ) stage 1 : hypopigmentation ( including trichrome and homogeneous lighter pigmentation ) ( figure 2 ) stage 2 : complete depigmentation with black hair and with perifollicular pigmentation ( figure 3 ) stage 3 : complete depigmentation with black hair and without perifollicular pigmentation ( figure 4 ) stage 4 : complete depigmentation with compound of white and black hair with / without perifollicular pigmentation ( figure 5 ) stage 5 : complete depigmentation plus significant hair whitening ( figure 6 ) notably an area where hair does not exist normally , like the extremities , is very resistant to treatment and placed in grade five . the total body veti is calculated using the following formula that includes contributions from all body regions : veti score : ( percentage of head involvement grade of tensity ) + ( percentage of trunk involvement grade of tensity ) 4 + ( percentage of upper limbs involvement grade of tensity ) 2 + ( percentage of lower limbs involvement grade of tensity ) 4 + ( percentage of genitalia involvement grade of tensity ) 0.1 the coefficients reported in this formula are based on percent of skin surface by the rule of nines . accordingly
the coefficient of head is 1 ( 9:9=1 ) , trunk and lower limb is 4 ( 36:9=4 ) , upper limb is 2 ( 18:9=2 ) and genitalia is almost 0.1(1:9= 0.1 ) .
percentage of involvement : p veti :
( phth)+(pttt)4+(putu)2+(pltl)4+(pgtg)0.1
5 + 20 + 10 + 20 + 0.5=55.5 the maximum score of veti is 55.5 . for example , in figure 3 if just the anterior of the body is involved , the veti is calculated as follows :
veti:(00)+(0.252)4+(00)2+(00)4+(00)0.1=2
vitiligo is an acquired depigmentary disorder characterized by the loss of functioning epidermal melanocytes and affects more than 0.51% of the worldwide population with devastating psychological and social consequences .
current lack of consensus on methods of assessment of this conundrum and inexistence of precise scoring to the extent that pasi does makes it principally impossible to evaluate the efficacy of new drugs or perform meta - analyses on the results of different studies of the same treatment .
several scores have been proposed to surmount this problem and offer more accurate measures of disease severity indexes and inter - individual variations . among the above scores designed for assessment of vitiligo ,
vasi provides a relatively simple method analogous to the psoriasis area severity index ( pasi ) and vitiligo european task force ( vetf ) is a more complex system that incorporates three components of vitiligo : extent , stage and progression of disease , but these scores have some limitations with discrepancy in results and , unlike the pasi score do not make a constant total number . regarding the other two scores , it should be pointed out that the vida score is based on the patient s opinion resulting in eventual discrepancy as a result .
pri is a predictive index for repigmentation in non - segmental vitiligo not a numerical index for measuring the extent and severity of vitiligo .
since the vida score is based on patient opinion , it makes sense to combine the vasi , vetf and some parts of the pri systems and invent a system much more similar to the pasi score with constant total number and less inter - individual differences .
veti score is a new treatment evaluation criteria and assessment method for vitiligo which can be easily handled in clinical practice .
although it is difficult to compare different modalities in vitiligo , we think veti score is more like the pasi score for psoriasis , and unlike other vitiligo scores , produces a constant and reproducible number and would greatly help clinical research on vitiligo patients .
notably , it has the potential to be a source of any computed application for researchers who work on vitiligo patients .
Output:
| although skin is the largest organ of the body , there are no standardized reproducible methods for assessing severity of many skin diseases . due to lack of consensus , methods of assessment and inexistence of precise scoring system
, there is no application for vitiligo estimation in real practice . in this paper
the author describes veti score as a new treatment evaluation criteria and severity assessment method for vitiligo .
this new tool , as does the pasi score in psoriasis , may be able to produce a constant and reproducible number and to help clinical research on vitiligo patients .
additionally it has a potential to be a source of any computed application for researchers working on vitiligo patients . |
PubmedSumm118785 | ***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: oxidative stress ( ros ) is accompanied by aging and several neurodegenerative diseases and cancers .
indeed , ros are generated as byproducts of cellular metabolism and have the potential to increase significant biological damage ( 1 ) .
there are several evidences to support the idea that the most important mechanism of protein oxidative damage is metal - catalyzed oxidation ( mco ) , leading to cleavage of polypeptide backbone , cross linking , and modification of the amino acid side chains leading to the loss of protein function and to structural alteration .
protein oxidation has become a crucial focus of research , as increased levels of oxidized proteins are one of the most important biomarkers of oxidative stress ( 2 , 3 ) .
it is almost clear that post - translational modifications ( ptms ) generated by oxidative damage from ros and rns on protein integrity are responsible for many pathologies and biological aging ( 3 ) .
this protein is the most abundant protein in human plasma with a molecular weight of 66 kd .
it has been well known that human serum albumin ( hsa ) is an easy target for ros ( 4 ) .
thereby , hsa is continuously exposed to oxidative stress , so that modifications of the conformation and function of hsa could happen and lead to alteration of its properties . by now
, it is shown that advanced oxidation protein products ( aopps ) are formed as a main result of interaction between plasma proteins , especially hsa , and hydroxyl radicals ( oh ) produced by fenton reaction , which takes place during ros production or ischemia events ( 5 ) . in the present study
, we chose a simple oxidation system consisting of h2o2 and feso4 , namely , fenton reaction , to induce the formation of hydroxyl radicals from h2o2 .
it is a common belief that the highly reactive hydroxyl radical ( ho ) is a main product generated in fenton s reaction ( 6 ) .
the aim of this work is to oxidize human serum albumin ( hsa ) by fenton reaction in various levels and quantified different protein damages such as carbonyl groups , protein degradation , fragmentations , aggregations , and thiol groups .
this experimental research was planned to study the effects of different ratios of a fenton system , ranging from 0.1 to 20 mm of h2o2 and a fixed concentration of feso4 ( 1 mm ) on hsa .
human serum albumin ( hsa ) ( sigma , a9511 ) , sodium dodecyl sulphate ( merck , germany ) , tetramethylethylenediamide ( applichem , a1148 ) , ammonium persulphate ( merck , germany ) , acrylamid for electrophoresis ( merck , germany ) , n - n-methylene diacrylamide ( merck , germany ) , sodium carbonate ( merck , millipore ) , formaldehyde 37% ( merck , germany ) , tris - base , methanol ( merck , germany ) , ethanol ( merck , germany ) , glycerol ( merck , germany ) , acetic acid ( glacial , merck ) , 2,4-dinitrophenylhydrazine ( daejung , south korea ) , trichloroacetic acid ( tca ) ( merck , germany ) , guanidine - hcl ( daejung , south korea ) , ethyl acetate for analysis ( merck , germany ) , bromophenol blue ( merck , germany ) , sodium thiosulfate pentahydrate ( merck , germany ) , hydrogen peroxide 30% ( merck , millipore ) , ferrous sulphate ( sigma , f7002 ) , dtnb(5,5-dithiobis(2-nitrobenzoic acid ) 99% ( sigma ) , hcl 37% ( merck , germany ) , 1,4-dithiothreitol ( scharlau chimie s.a , european union ) , coomassie brilliant blue g250 for electrophoresis ( merck , germany ) .
the concentration of h2o2 stock solution ( 0.4 m ) , typically 30% ( v / v ) h2o2 , was determined accurately using a molar extinction coefficient ( ) of 39.4m-1 cm-1 at 240 nm .
all spectrophotometer analysis was performed by a nanodrop 2000 uv - vis spectrophotometer , thermo fisher scientific inc . under in vitro conditions , fe2 + is able to generate the oh by modification of h2o2 according to the fenton redox reaction ( 7 ) .
the metal - catalyzed oxidation was launched in 10 mm potassium phosphate buffer ph 7 .
oxidation was accomplished by supplementing 500 l of protein solution ( 1 mg / ml ) with a freshly prepared mixture of feso4 ( 1 mm ) to increasing concentrations of h2o2 between 0.1 and 20 mm .
the reaction was incubated for 30 min at room temperature and stopped by addition of cold 10% tca ( 8 , 9 ) .
subsequently , samples centrifuged at 10000g for 15 min and washed three times with 10% tca ( 8) . finally , supernatant was removed and pellets were dissolved in 10 mm phosphate buffer ph 7 .
all experiments were carried out in triplicate . after treating human serum albumin ( 1 mg / ml ) with fenton reaction , its modifications were analyzed by sodium dodecyl sulphate / polyacrylamide gel electrophoresis ( sds - page ) under reducing conditions . before putting samples ( 4gr ) in each well , they were treated with 10% sds , 0.5 m tris - base ph 6.8 , 2.7 mm glycerol and 0.2 m dithiothreitol ( dtt ) and resolved by 8% sds - page according to laemmli s method ( 10 ) . for gel staining , each gel was dyed with coomassie blue g-250 .
image analysis was carried out using a labscan machine ( powered by melanie ) and analyzed with imagej software . the software allowed background subtraction , automatic band detection , and comparative analysis of normalized band optical densities ( ods ) .
protein carbonylation assay was performed by spectrophotometric dnph assay for detection of protein carbonyl groups ( 11 ) .
briefly , 200l of each sample were incubated with 200l of dnph 0.2% ( prepared in 2n hcl ) in the dark for 1 hour at room temperature and vortexed each 10 minutes .
the samples were precipitated by an ice cold solution of tca 20 % and centrifuges at 10000 rpm for 10 minutes .
collected pellets were washed three times with ethanol / ethyl acetate ( 1/1 ; v / v ) to remove the excess of dnph reagent .
the resulting protein pellet was dissolved in 100 l of 6 m guhcl , and the absorbance was measured at 370 nm against blank ( hcl treated ) as reference . to quantify the level of protein carbonylation groups
, we used the molar extinction coefficient ( 22000 m -1 cm -1 ) and expressed protein carbonyl groups in mol carbonyl per mol protein .
we calculated carbonyl / protein concentration ( molc / molp ) by division of carbonyl content to protein concentration .
the free thiol concentration of protein was measured by ellman s reagent ( 11 ) .
a 50 l of protein solution ( 2mg / ml ) was dispensed into 1ml centrifuge tubes and 50 l of dtnb ( 0.5 mm ) , prepared in 100 mm phosphate buffer ph 7 , was added to each sample .
finally , all solutions were vortexed and incubated in the dark conditions for 30 min at room temperature . a protein solution consisted of 50 l of 100 mm phosphate buffer , plus 50 l of protein solution
in addition , a dtt ( 10 mm ) group was chosen as a positive control group .
absorbance of each solution was measured at 412 nm against blank as follows : absorbance change = a412 ( protein+dtnb ) - a412 ( protein + phosphate buffer )
a thiol concentration was determined for each solution by dividing the above value by an extinction coefficient at 412 ( 13600 m-1 cm-1 ) .
this experimental research was planned to study the effects of different ratios of a fenton system , ranging from 0.1 to 20 mm of h2o2 and a fixed concentration of feso4 ( 1 mm ) on hsa .
human serum albumin ( hsa ) ( sigma , a9511 ) , sodium dodecyl sulphate ( merck , germany ) , tetramethylethylenediamide ( applichem , a1148 ) , ammonium persulphate ( merck , germany ) , acrylamid for electrophoresis ( merck , germany ) , n - n-methylene diacrylamide ( merck , germany ) , sodium carbonate ( merck , millipore ) , formaldehyde 37% ( merck , germany ) , tris - base , methanol ( merck , germany ) , ethanol ( merck , germany ) , glycerol ( merck , germany ) , acetic acid ( glacial , merck ) , 2,4-dinitrophenylhydrazine ( daejung , south korea ) , trichloroacetic acid ( tca ) ( merck , germany ) , guanidine - hcl ( daejung , south korea ) , ethyl acetate for analysis ( merck , germany ) , bromophenol blue ( merck , germany ) , sodium thiosulfate pentahydrate ( merck , germany ) , hydrogen peroxide 30% ( merck , millipore ) , ferrous sulphate ( sigma , f7002 ) , dtnb(5,5-dithiobis(2-nitrobenzoic acid ) 99% ( sigma ) , hcl 37% ( merck , germany ) , 1,4-dithiothreitol ( scharlau chimie s.a , european union ) , coomassie brilliant blue g250 for electrophoresis ( merck , germany ) .
the concentration of h2o2 stock solution ( 0.4 m ) , typically 30% ( v / v ) h2o2 , was determined accurately using a molar extinction coefficient ( ) of 39.4m-1 cm-1 at 240 nm .
all spectrophotometer analysis was performed by a nanodrop 2000 uv - vis spectrophotometer , thermo fisher scientific inc .
under in vitro conditions , fe2 + is able to generate the oh by modification of h2o2 according to the fenton redox reaction ( 7 ) .
the metal - catalyzed oxidation was launched in 10 mm potassium phosphate buffer ph 7 .
oxidation was accomplished by supplementing 500 l of protein solution ( 1 mg / ml ) with a freshly prepared mixture of feso4 ( 1 mm ) to increasing concentrations of h2o2 between 0.1 and 20 mm .
the reaction was incubated for 30 min at room temperature and stopped by addition of cold 10% tca ( 8 , 9 ) .
subsequently , samples centrifuged at 10000g for 15 min and washed three times with 10% tca ( 8) . finally , supernatant was removed and pellets were dissolved in 10 mm phosphate buffer ph 7 .
after treating human serum albumin ( 1 mg / ml ) with fenton reaction , its modifications were analyzed by sodium dodecyl sulphate / polyacrylamide gel electrophoresis ( sds - page ) under reducing conditions . before putting samples ( 4gr ) in each well ,
they were treated with 10% sds , 0.5 m tris - base ph 6.8 , 2.7 mm glycerol and 0.2 m dithiothreitol ( dtt ) and resolved by 8% sds - page according to laemmli s method ( 10 ) . for gel staining , each gel was dyed with coomassie blue g-250 .
image analysis was carried out using a labscan machine ( powered by melanie ) and analyzed with imagej software .
the software allowed background subtraction , automatic band detection , and comparative analysis of normalized band optical densities ( ods ) .
protein carbonylation assay was performed by spectrophotometric dnph assay for detection of protein carbonyl groups ( 11 ) .
briefly , 200l of each sample were incubated with 200l of dnph 0.2% ( prepared in 2n hcl ) in the dark for 1 hour at room temperature and vortexed each 10 minutes .
the samples were precipitated by an ice cold solution of tca 20 % and centrifuges at 10000 rpm for 10 minutes .
collected pellets were washed three times with ethanol / ethyl acetate ( 1/1 ; v / v ) to remove the excess of dnph reagent .
the resulting protein pellet was dissolved in 100 l of 6 m guhcl , and the absorbance was measured at 370 nm against blank ( hcl treated ) as reference . to quantify the level of protein carbonylation groups
, we used the molar extinction coefficient ( 22000 m -1 cm -1 ) and expressed protein carbonyl groups in mol carbonyl per mol protein .
we calculated carbonyl / protein concentration ( molc / molp ) by division of carbonyl content to protein concentration .
the free thiol concentration of protein was measured by ellman s reagent ( 11 ) .
a 50 l of protein solution ( 2mg / ml ) was dispensed into 1ml centrifuge tubes and 50 l of dtnb ( 0.5 mm ) , prepared in 100 mm phosphate buffer ph 7 , was added to each sample .
finally , all solutions were vortexed and incubated in the dark conditions for 30 min at room temperature .
a protein solution consisted of 50 l of 100 mm phosphate buffer , plus 50 l of protein solution was selected as blank for each group .
in addition , a dtt ( 10 mm ) group was chosen as a positive control group .
absorbance of each solution was measured at 412 nm against blank as follows : absorbance change = a412 ( protein+dtnb ) - a412 ( protein + phosphate buffer ) a412 ( dtnb alone blank ) .
a thiol concentration was determined for each solution by dividing the above value by an extinction coefficient at 412 ( 13600 m-1 cm-1 ) .
sds - page is a practical technique to analyze protein damages that were produced by fenton reaction
. a fenton reaction may give rise to breakage of polypeptide chains through oxidative damage of amino acids in protein , and these damages can be visualized by the creation of cross links , fragments , and smearing of the gel .
densitometry of bands showed the loss of protein in higher ratios of a fenton system .
fenton products caused breakage of covalent bonds , the effects of which are illustrated in the sds - page portrait by progressive disappearance of monomer band ( figure 1b ) .
the results demonstrated that , by increasing the hydrogen peroxide concentration , the rate of protein removal was increased .
this is owing to the formation of more hydroxyl radicals . as can be seen in the sds - page profile ( figure 1a )
, there is no aggregation or cross link due to formation of covalent bands between specific amino acids such as tyrosine leading to dimer and oligomer . considering the sds - page profile
, protein fragmentations are increasing in higher ratios of fenton reaction ( figure 1b ) .
it is noteworthy that , in the highest ratio of the fenton system , about 50% of native protein has broken down .
it can be obviously seen that the sample treated with h2o2 has approximately the same band intensity compared with non - oxidized protein , but the fe2 + treated group showed a 40% drop in its band densitometry against native counterpart ( figure 1c ) .
protein carbonylation is the most deteriorating irreversible modification as a result of oxidative stress ( 12 ) . according to figure 2
, a carbonyl / protein ( mol / mol ) ratio is increasing linearly in lower fenton ratios and the values plateau at higher levels of h2o2/fe 2 + .
it is noteworthy that reaction of hsa with h2o2 alone gave a low level of carbonyl groups bound to protein ( 0.0880.012 ) while fe2 + treatment at a fixed concentration ( 1 mm ) could produce a significant level of carbonyl on protein by itself ( 0.420.019 ) .
these results indicate that the type of oxidizing agent can play an important role in protein carbonylation and are consistent with former results presented by madian et al .
( 14 ) . as previous studies showed , conversion of proline , lysine , arginine , and hystidine residues ( rkpt ) into carbonyl derivatives
is the most important precursor of carbonylated compounds , which increase the susceptibility and sensitivity of hsa to irreversible modification owing to oxidative stress ( 12 ) .
as there are several rkpt - enriched regions on this protein , this increased the sensitivity of this protein to damage by oxidants .
nevertheless , metal catalyzed oxidation ( mco ) of a protein may be a site - specific process , in which fe ( ii ) makes a complex with protein and react with h2o2 to yield oh .
it was shown that hydroxyl radicals are able to generate structural changes in the n - terminal side of hsa ( 5 ) .
these results revealed that hydroxyl radicals which have been formed through fenton reaction in in vivo conditions can present a new source of numerous ros and rns producers in the animal s body .
hsa is a great antioxidant in blood owing to its free thiol at cys-3 , which accounts for about 80% of the total plasma thiol component ( 15 ) . in the present study
, we investigated the possible effect of fenton reaction on hsa ( 1 mg / ml ) in various levels of oxidation .
our results showed that the ratio of thiol / protein was 0.26 0.05 ( molt / molp ) for native protein .
after oxidation of samples through fenton reaction , the ratios have dipped to zero in each sample .
although the thiol content for a feso4 ( 1 mm ) treated sample , alone , was 0.23 0.02 ( molt / molp ) , it is important to note that the thiol ratio also has dropped to zero in h2o2 exposed solely .
these results are in accordance with the former investigation , which has indicated the h2o2-mediated and fenton reaction oxidation of thiol groups ( 16 ) . as for the positive control group ( dtt group ) ,
hsa ( 66kd ) is a heart - shape protein containing 585 residues ( 17 ) .
it contains 35 cysteine amino acids , in which all of these residues are engaged in the formation of 17 disulfide bonds except cys-34 , containing the only free thiol group .
several studies have shown the modification of free sh group on cys to different oxidized products such as sulfenic acid ( soh ) , sulfinic acid ( so2h ) , sulfonic acid ( so3h ) through different ros ( 18 ) . moreover
, it has shown that oh radicals , which are produced through gamma radiolysis and fenton reaction , have an important role in protein oxidation and totally oxidative stress ( 19 ) . in this report
, we propose an antioxidant activity of hsa owing to simple reduction of sulfhydryl groups on cys-34 exposed with increasing amounts of oh radicals produced by fenton system .
the results are in agreement with the former report concerning the radical scavenger properties of hsa through the free thiol group on cys-34 residue ( 20 , 21 ) . despite this , we need to analyze the structure of oxidized hsa precisely to identify the actual modifications of sulfhydryl side chain of this residue .
regarding the fact that carbonylation is site selective , this phenomenon may be due to its structure or conformation .
these findings confirmed the results of guilherme vargas bochi et al . , indicating advanced oxidation products ( aopps ) formation as a result of fenton reaction ( 4 ) .
it would be of interest to say that hsa has no propensity to the formation of cross link , as we have no protein aggregation in the sds - page profile .
however , the band s densitometry indicates the loss of protein in a higher level of the fenton system .
it is important to point out that protein carbonylation ( figure 2 ) and band densitometry disappearance ( figure 1a ) are increasing in higher levels of fenton reaction , concomitantly .
considering the sds - page profile , breakdown of the polypeptide chain results in the formation of destroyed low - molecular - weight subunits .
schuessler and schilling showed that proline subunits are the main target for chain sequestering in bsa ( 22 ) .
for quantification of thiol and carbonyl groups , the dtnb and dnph assays were used as sensitive methods , respectively . as these techniques were not qualified to identify the types of oxidation products on the protein structure , we could not report on the type of oxidation byproducts that has been formed on protein throughout this study .
sds - page is a practical technique to analyze protein damages that were produced by fenton reaction
. a fenton reaction may give rise to breakage of polypeptide chains through oxidative damage of amino acids in protein , and these damages can be visualized by the creation of cross links , fragments , and smearing of the gel .
densitometry of bands showed the loss of protein in higher ratios of a fenton system .
fenton products caused breakage of covalent bonds , the effects of which are illustrated in the sds - page portrait by progressive disappearance of monomer band ( figure 1b ) .
the results demonstrated that , by increasing the hydrogen peroxide concentration , the rate of protein removal was increased .
this is owing to the formation of more hydroxyl radicals . as can be seen in the sds - page profile ( figure 1a )
, there is no aggregation or cross link due to formation of covalent bands between specific amino acids such as tyrosine leading to dimer and oligomer . considering the sds - page profile
, protein fragmentations are increasing in higher ratios of fenton reaction ( figure 1b ) .
it is noteworthy that , in the highest ratio of the fenton system , about 50% of native protein has broken down .
it can be obviously seen that the sample treated with h2o2 has approximately the same band intensity compared with non - oxidized protein , but the fe2 + treated group showed a 40% drop in its band densitometry against native counterpart ( figure 1c ) .
protein carbonylation is the most deteriorating irreversible modification as a result of oxidative stress ( 12 ) . according to figure 2
, a carbonyl / protein ( mol / mol ) ratio is increasing linearly in lower fenton ratios and the values plateau at higher levels of h2o2/fe 2 + .
it is noteworthy that reaction of hsa with h2o2 alone gave a low level of carbonyl groups bound to protein ( 0.0880.012 ) while fe2 + treatment at a fixed concentration ( 1 mm ) could produce a significant level of carbonyl on protein by itself ( 0.420.019 ) .
these results indicate that the type of oxidizing agent can play an important role in protein carbonylation and are consistent with former results presented by madian et al .
( 14 ) . as previous studies showed , conversion of proline , lysine , arginine , and hystidine residues ( rkpt ) into carbonyl derivatives
is the most important precursor of carbonylated compounds , which increase the susceptibility and sensitivity of hsa to irreversible modification owing to oxidative stress ( 12 ) .
as there are several rkpt - enriched regions on this protein , this increased the sensitivity of this protein to damage by oxidants .
nevertheless , metal catalyzed oxidation ( mco ) of a protein may be a site - specific process , in which fe ( ii ) makes a complex with protein and react with h2o2 to yield oh .
it was shown that hydroxyl radicals are able to generate structural changes in the n - terminal side of hsa ( 5 ) .
these results revealed that hydroxyl radicals which have been formed through fenton reaction in in vivo conditions can present a new source of numerous ros and rns producers in the animal s body .
hsa is a great antioxidant in blood owing to its free thiol at cys-3 , which accounts for about 80% of the total plasma thiol component ( 15 ) . in the present study
, we investigated the possible effect of fenton reaction on hsa ( 1 mg / ml ) in various levels of oxidation .
our results showed that the ratio of thiol / protein was 0.26 0.05 ( molt / molp ) for native protein .
after oxidation of samples through fenton reaction , the ratios have dipped to zero in each sample . although the thiol content for a feso4 ( 1 mm ) treated sample , alone , was 0.23 0.02 ( molt / molp ) , it is important to note that the thiol ratio also has dropped to zero in h2o2 exposed solely .
these results are in accordance with the former investigation , which has indicated the h2o2-mediated and fenton reaction oxidation of thiol groups ( 16 ) . as for the positive control group ( dtt group ) ,
hsa ( 66kd ) is a heart - shape protein containing 585 residues ( 17 ) .
it contains 35 cysteine amino acids , in which all of these residues are engaged in the formation of 17 disulfide bonds except cys-34 , containing the only free thiol group .
several studies have shown the modification of free sh group on cys to different oxidized products such as sulfenic acid ( soh ) , sulfinic acid ( so2h ) , sulfonic acid ( so3h ) through different ros ( 18 ) . moreover , it has shown that oh radicals , which are produced through gamma radiolysis and fenton reaction , have an important role in protein oxidation and totally oxidative stress ( 19 ) . in this report , we propose an antioxidant activity of hsa owing to simple reduction of sulfhydryl groups on cys-34 exposed with increasing amounts of oh radicals produced by fenton system .
the results are in agreement with the former report concerning the radical scavenger properties of hsa through the free thiol group on cys-34 residue ( 20 , 21 ) . despite this
, we need to analyze the structure of oxidized hsa precisely to identify the actual modifications of sulfhydryl side chain of this residue . our results indicated that hsa has a significant propensity to protein carbonylation .
regarding the fact that carbonylation is site selective , this phenomenon may be due to its structure or conformation .
, indicating advanced oxidation products ( aopps ) formation as a result of fenton reaction ( 4 ) .
it would be of interest to say that hsa has no propensity to the formation of cross link , as we have no protein aggregation in the sds - page profile .
however , the band s densitometry indicates the loss of protein in a higher level of the fenton system .
it is important to point out that protein carbonylation ( figure 2 ) and band densitometry disappearance ( figure 1a ) are increasing in higher levels of fenton reaction , concomitantly . considering the sds - page profile , breakdown of the polypeptide chain results in the formation of destroyed low - molecular - weight subunits .
schuessler and schilling showed that proline subunits are the main target for chain sequestering in bsa ( 22 ) .
for quantification of thiol and carbonyl groups , the dtnb and dnph assays were used as sensitive methods , respectively . as these techniques were not qualified to identify the types of oxidation products on the protein structure , we could not report on the type of oxidation byproducts that has been formed on protein throughout this study .
in conclusion , our data propose that fenton reaction may be an important pathway to the harmful effect on human serum albumin .
to scrutinize the structural and conformational damages created through oxidation , other techniques are underway .
in addition , the modification of protein arrangement after oxidation will be later investigated using tem .
Output:
| introductionhuman serum albumin ( hsa ) is a critical protein in human blood plasma , which can be highly damaged by oxidative stress .
the aim of this study was to analyze modifications of this protein after oxidation using a fenton system.methodsin this 2015 experiment , different ratios of fenton reagent ( fe2+/h2o2 ) was incubated with one concentration of human serum albumin ( 1mg / ml ) .
hence , hsa was incubated 30 min with various combinations of a fenton system and quantified oxidation products such as carbonyl groups , fragmentations , degradations , and oxidized free thiol group using reliable techniques .
image and data analysis were carried out using imagej software and excel ( version 2007 ) , respectively.resultsan sds - page profile showed no cross link and aggregation . however , protein band intensity has decreased to 50% in the highest ratio of h2o2/fe .
carbonylation assay indicated carbonyl / protein ( molc / molp ) ratio increased linearly in lower ratios and the values plateau at higher levels of h2o2/fe 2 + .
the only free sulfhydryl group on hsa was oxidized in all ratios of the fenton system.conclusionto sum , the structure of hsa has been changed following treatment with hydroxyl radical as the main product of fenton reaction .
these data confirm the antioxidant activity of hsa . |
PubmedSumm118786 | ***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 identification , in the mid-1960s , of the major psycochoactive component of cannabis sativa and marijuana ( 9-tetrahydrocannabinol , 9 thc ) and the discovery of its membrane receptors , paved the way to reveal a whole endogenous signaling system known as the endocannabinoid ( ec ) system ( 7 ) .
several studies have demonstrated the role of the ec system in physiological functions , such as homeostasis and stress response .
ec have neuroprotective and analgesic properties , controlling movement and some memory processes ( 8 , 9 )
finally , ec influence the pulmonary and cardiovascular system , controlling blood pressure and heart rhythm and having bronchodilatating properties ( 69 ) .
anandamide ( n - arachidonoyl - ethanolamine ( aea ) ) and 2-arachidonoyl - glycerol ( 2-ag ) are the most studied ec , but recently new synthetic and non - synthetic molecules have been proposed as cannabinoid receptor agonists ( fig .
it is well established that aea and 2-ag are not prestored in secretory vesicles but are de novo biosynthesized following an increase in the intracellular concentration of calcium , within a framework of a metabolic reaction involving phospholipid precursors ( n - acyl - phosphatidyl - ethanolamine and diacylglycerol ) and specific calcium - sensitive enzymes ( phospholipasis d and diacylglycerol lipasis ) .
ec are released from the cell immediately after their biosynthesis and then quickly removed from the extracellular space by a rapid and selective cellular reuptake mechanism ( not yet clear ) . in particular , ec transport is not leaded by transmembrane ionic gradients , but to passive diffusion through a transporter not yet identified . instead , ec degradation consists of the hydrolysis of aea to ethanolamine and arachidonic acid by fatty acid amide hydrolase ( faah ) and of 2-ag by monoacyl - glycerol lipases ( 6 , 7 ) . to date
, only two cannabinoid receptors have been cloned : the cb1 and cb2 receptors ( 8 , 9 ) . at first
the cb1 receptor was thought to be expressed just in the cortical brain region ( neocortex , hippocampus , amigdala ) , in the basal ganglia , in the mesolimbic system , in the thalamus and hypothalamus and in the cerebellum : neurons of these areas regulate the expression of orexigenic and anorexigenic signals ( 10 , 11 ) .
recent studies have demonstrated that cb1 receptors are expressed in peripheral cells and tissues controlling energy homeostasis , including gut , liver adipocytes , skeletal muscle and pancreas .
cb2 receptors are present in several immune cells and blood cells where they participate in the regulation of cytokine release and function ( 10 ) .
nevertheless , cb2 receptors also develop functions in other cells such as the cheratinocitis , the osteoclastis and the endocrine pancreas .
since cb2 agonists have no psychological effects on central nervous system they have become the object of numerous studies in the therapeutic use of cannabinoids , particularly as regards the analgesic , anti - inflammatory and antineoplastic effects .
synthetic cannabinoids have been created so as to act as highly selective agonists or antagonists for cb1 or cb2 receptors . 9-tetrahydrocannabinol and
2-ag approximately have similar affinity for cb1 and cb2 receptors , while the aea has a marginal selectivity for cb1 receptors . however , the effectiveness of the 9-thc and the aea is lower in cb2 receptor than in cb1 receptor ( 7 ) .
both receptors belong to the family of the receptors coupled to the g protein ( gpcrs ) .
the intracellular signaling events include :
inhibition of stimulus - induced adenylate cyclase and subsequent impairment of camp / protein kinase a - mediated short and long - term effects;stimulation of mitogen - activated protein kinase signaling;in case of cb1 receptors , inhibition of voltage - gated ca channels and stimulation of inwardly rectifying g protein - coupled k channels;in case of cb1 , stimulation of phosphatidylinositol 3-kinase and of intracellular ca mobilization ( 7 ) .
inhibition of stimulus - induced adenylate cyclase and subsequent impairment of camp / protein kinase a - mediated short and long - term effects ; stimulation of mitogen - activated protein kinase signaling ; in case of cb1 receptors , inhibition of voltage - gated ca channels and stimulation of inwardly rectifying g protein - coupled k channels ; in case of cb1 , stimulation of phosphatidylinositol 3-kinase and of intracellular ca mobilization ( 7 ) .
anandamide ( n - arachidonoyl - ethanolamine ( aea ) ) and 2-arachidonoyl - glycerol ( 2-ag ) are the most studied ec , but recently new synthetic and non - synthetic molecules have been proposed as cannabinoid receptor agonists ( fig .
it is well established that aea and 2-ag are not prestored in secretory vesicles but are de novo biosynthesized following an increase in the intracellular concentration of calcium , within a framework of a metabolic reaction involving phospholipid precursors ( n - acyl - phosphatidyl - ethanolamine and diacylglycerol ) and specific calcium - sensitive enzymes ( phospholipasis d and diacylglycerol lipasis ) .
ec are released from the cell immediately after their biosynthesis and then quickly removed from the extracellular space by a rapid and selective cellular reuptake mechanism ( not yet clear ) . in particular , ec transport is not leaded by transmembrane ionic gradients , but to passive diffusion through a transporter not yet identified . instead
, ec degradation consists of the hydrolysis of aea to ethanolamine and arachidonic acid by fatty acid amide hydrolase ( faah ) and of 2-ag by monoacyl - glycerol lipases ( 6 , 7 ) .
to date , only two cannabinoid receptors have been cloned : the cb1 and cb2 receptors ( 8 , 9 ) . at first the cb1 receptor was thought to be expressed just in the cortical brain region ( neocortex , hippocampus , amigdala ) , in the basal ganglia , in the mesolimbic system , in the thalamus and hypothalamus and in the cerebellum : neurons of these areas regulate the expression of orexigenic and anorexigenic signals ( 10 , 11 ) .
recent studies have demonstrated that cb1 receptors are expressed in peripheral cells and tissues controlling energy homeostasis , including gut , liver adipocytes , skeletal muscle and pancreas .
cb2 receptors are present in several immune cells and blood cells where they participate in the regulation of cytokine release and function ( 10 ) .
nevertheless , cb2 receptors also develop functions in other cells such as the cheratinocitis , the osteoclastis and the endocrine pancreas .
since cb2 agonists have no psychological effects on central nervous system they have become the object of numerous studies in the therapeutic use of cannabinoids , particularly as regards the analgesic , anti - inflammatory and antineoplastic effects .
synthetic cannabinoids have been created so as to act as highly selective agonists or antagonists for cb1 or cb2 receptors . 9-tetrahydrocannabinol and 2-ag approximately have similar affinity for cb1 and cb2 receptors , while the aea has a marginal selectivity for cb1 receptors .
however , the effectiveness of the 9-thc and the aea is lower in cb2 receptor than in cb1 receptor ( 7 ) .
both receptors belong to the family of the receptors coupled to the g protein ( gpcrs ) .
the intracellular signaling events include :
inhibition of stimulus - induced adenylate cyclase and subsequent impairment of camp / protein kinase a - mediated short and long - term effects;stimulation of mitogen - activated protein kinase signaling;in case of cb1 receptors , inhibition of voltage - gated ca channels and stimulation of inwardly rectifying g protein - coupled k channels;in case of cb1 , stimulation of phosphatidylinositol 3-kinase and of intracellular ca mobilization ( 7 ) .
inhibition of stimulus - induced adenylate cyclase and subsequent impairment of camp / protein kinase a - mediated short and long - term effects ; stimulation of mitogen - activated protein kinase signaling ; in case of cb1 receptors , inhibition of voltage - gated ca channels and stimulation of inwardly rectifying g protein - coupled k channels ; in case of cb1 , stimulation of phosphatidylinositol 3-kinase and of intracellular ca mobilization ( 7 ) .
the ec system participates in the modulation of the so - called mechanisms of pleasure and the manipulation of this system influences appetite .
elevated cb1 expression in cerebral areas involved in the control of pleasure indicates a strong involvement of this system in different psychological functions , regulated by these regions of the brain , including appetite ( 10 ) . under these circumstances , the ingested food that acts on the nervous fibers which connect the hindbrain and the midbrain to the hypothalamus influences dopamine , opioids , serotonine and noradrenaline modulating appetite and satisfaction .
the study of this system clearly shows the existence of an increase of dopamine extracellular levels inside the accumbens nucleus after the ingestion of tasty food .
psychoactive drugs such as marijuana and ethanolol , but also pleasant stimuli or tasty foods , are known to induce the release of dopamine in specific cerebral regions . at this level , the existence of a relationship has also been shown between the ec system and the oppioid and serotoninergic system ( 12 ) .
it is now widely accepted that ec released from depolarized post - synaptic neurons retrogradely activate presynaptic cb1 receptors , thereby reducing both inhibitory ( gaba mediated ) and excitatory ( glutamate mediated ) neurotransmission .
this property seems to participate in ec regulation of the hypothalamic networks and of the anorexigenic ( arcuate nucleus expressing cocaine - amphetamine regulated transcript cart and paraventricular nucleus expressing corticotrophin - releasing hormone ) and orexigenic signals ( lateral hypoyhalamus neurons containing melanin - concentrating - hormone and orexins ) ( 1315 ) .
signals coming from various peripheral organs such as the liver , the gut and the adipose tissue direct hormonal and biochemical signals to the hypothalamus to notify the central nervous system about nutritional state .
an example of this peripheral control is leptin , a hormone produced only by adipose tissue able to interact with specific receptors located in the hypothalamus to carry an anorexigenic signal .
the ec system is modulated by leptin too ; it was demonstrated that acute treatment with leptin reduces hypothalamic levels of aea and 2-ag in normal mice , but above all it was underlined that , in mice made obese and hyperphagic by a defect of the leptin signal , ec hypothalamic levels are permanently and pathologically elevated ( 14 , 15 ) .
finally , some experimental evidence indicated that ec and cb1 receptors regulate energetic metabolism through a peripheral action at the level of the adipose tissue , liver and pancreas ( 1618 ) .
cota et al ( 11 ) demonstrated for the first time that wild - type rats exhibit significantly higher amounts of fat mass than cb1 receptor deficient rats .
in addition , cb1 receptors stimulate lipoprotein lipase ; as a consequence they activate lipogenesis , suggesting that ec contribute to the accumulation of body fat not only stimulating food intake , but also acting directly at the adipose tissue level .
recent studies in vitro on adipose cell cultures underlined that cb1 receptors blockage induces an arrest of adipocytis proliferation , while chronic stimulation of these receptors induces differentiation of preadipocytis to adipocytis , shown by the early appearance of the differentiation marker ppar ( peroxisome proliferator activated receptor ) .
these results confirm that ec actively participate in adipogenesis and fat accumulation ; however , it was observed that aea is able to act on ppar receptors , independently from cb1 receptors ( 7 ) . in the liver ,
cb1 receptors are expressed around the centrolobular vein , where , stimulating the expression of srebp-1c ( steroid regulatory element binding protein 1-c ) and its target ( acetilcoa - carboxylase 1 and fatty acid synthase ) , they activate lipogenesis and fatty acid synthesis ( 7 ) .
more recently , it was observed that ec are able to regulate insulin levels , peripheral glucose uptake ; and therefore , to increase glucose tolerance . ec through cb1 activation , would seem to be able to modify the secretion of ca and , therefore , of insulin ( 19 ) .
nevertheless , further studies will be necessary to define the role of the ec system in the pancreas .
this recent hypothesis is supported by a series of studies developed on animal models of obesity ; nevertheless , it still needs to be demonstrated in humans .
it was demonstrated that the cb1 receptor is overex - pressed in tissues which control energetic metabolism such as the liver ( 18 ) , skeletal muscles ( 9 ) and the adipose organ ( 12 , 16 ) when animals are made obese by a high fat diet . in addition , the most important demonstration about metabolism , is that the hyperactivation of the ec system induces in adipocyte cultures a reduction in the levels of adiponectin and an increase in visfatin , two adipokines having opposing roles .
adiponectin , a hormone produced only by adipose tissue , plays an important role in the modulation of fat and glucose metabolism , because it inhibits hepatic gluconeogenesis and controls free fatty acid production , through the suppression of lipogenesis and the activation of fatty acid oxidation ( 16 ) ( fig .
2effects of rimonobant on adiponectin mrna levels in lean and obese rats and in cb1 knockout mice .
effects of rimonobant on adiponectin mrna levels in lean and obese rats and in cb1 knockout mice .
it is still premature to express a judgment on the clinical meaning of circulating levels of ec in humans and the mechanisms that would stimulate overactivity of the ec system in obesity remain unclear . in obese women , with no others comorbidities , and whose cause of obesity was correlated to alimentary disorders or to the menopause , aea and 2-ag levels were significantly greater than in the control group ( 17 ) ( fig .
3 ) . in addition , in patients affected by diabetes mellitus type 2 , ec levels were significantly greater than in non - diabetic controls ( 20 ) .
according to a recent study ( 21 ) , a possible mechanism of ec system hyperactivation would be represented by a reduced degradation of aea ; the authors identified in a population of obese subjects a polymorphism , at the level of the faah sequence , the enzyme appointed to the degradation of aea , which would behave as reduced enzymatic activity ( 21 ) .
the increasing evidence of the role of the ec system in the regulation of food intake and energetic balance has stimulated the development of cb1 receptor blockers , whose the most studied one in the treatment of obesity is rimonabant ( fig .
4possible action mechanisms of cb1 receptor blockers and rimonabant effects .
possible action mechanisms of cb1 receptor blockers and rimonabant effects .
an extensive study of experimental phase iii denominated rio ( rimonabant in obesity ) , was conducted on about 6600 obese or overweight patients ( 22 ) .
this experiment was composed of four substudies ( rio - north america , rio - europe , rio - lipids and rio - diabetes ) directed to identify the effectiveness of rimonabant on bodyweight as a primary end - point and on various metabolic alterations such as secondary end - point .
the pharmacological treatment , of 5 or 20 mg of rimonabant vs. placebo , was associated with a reduction in energy intake of 600 calories in respect of basal metabolic rate and to an increase in physical activity ( fig .
( 23 ) compared to rio - europe ( 24 ) , patients enrolled after the first year were re - randomized to placebo or rimonabant , for monitoring possible resumption of body weight at the end of the drug treatment .
rio - lipids ( 25 ) and rio - diabetes ( 26 ) were programmed for investigating the improvements due to the administration of rimonabant , in patients that were associated with obesity or with overweight diabetes and dyslipidemia , respectively .
treatment with rimonabant 20 mg produced results significantly greater than 5 mg and the results were equivalent for primary and secondary endpoints .
the treatment with 20 mg rimonabant determined in comparison to the placebo group a significant reduction in body weight ( 8.7 vs. 2.8 kg in rio - north america , 8.6 vs. 3.6 kg in rio - europe , 8.6 vs. 2.3 kg in rio - lipids , 6.1 vs. 1.9 kg in rio - diabetes ) and of waist circumference ( 8.5 vs. 4 cm in rio - north america , 9 vs. 3 cm in rio - europe , 9 vs. 4 cm in rio - lipids , 5.2 vs. 1.9 cm in rio - diabetes ) ( fig . 6 ) . in the group treated with rimonabant a significant improvement in the lipidic profile was also observed , with an increase in high - density lipoprotein ( hdl ) cholesterol , a reduction in triglycerides , and an improvement in glycemia and insulinemia during oral glucose tolerance test .
6results of rio : reduction in body - weight in rimonabant vs. placebo group .
results of rio : reduction in body - weight in rimonabant vs. placebo group . in rio - lipids ,
changes in leptin and adiponectin levels were observed , demonstrating a significant decrease of leptin and an increase of the circulating levels of adiponectin in patients treated with rimonabant .
multivariate analysis showed that rimonabant had independent positive effects from weight loss on lipidic profile and adiponectin levels . in rio - europe around 50% of the variation in hdl cholesterol and in triglycerides
was independent from weight loss , while in the rio - lipids the increase of 57% in adiponectin did not seem justifiable on the basis of caloric reduction only , but rather related to the peripheral action of rimonabant . in rio - diabetes , the hba1 levels were lower in both rimonabant groups compared to the placebo group and showed a persistent reduction in the rimonabant 20 mg group .
in addition , it was possible to show that the reduction of hba1 levels , that was two - fold higher than the reduction due to weight loss , was independent from the reduction in body weight , related to a peripheral action of rimonabant . finally , in rio - north america during the second year of treatment in the group that continued with rimonabant , a continuous and progressive reduction in body weight was observed , while in the group randomized to placebo a recovery of most of the weight lost during the first year was associated with an increase in triglycerides and a reduction in hdl cholesterol .
rimonabant was generally well tolerated and the most frequent side effects were gastrointestinal ( nausea and diarrhea ) and humoral ( anxiety and depression ) .
the prevalence of obesity is continuously increasing and represents one of the principal causes of cardiovascular morbidity and mortality .
the recent discovery of the role of the ec system in the control of energetic metabolism and the presence of the overactivity of this system in obesity , has enabled the development of new drugs , antagonists of cb1 receptors such as rimonabant .
these drugs are able not only to determine a reduction in body weight , but also to promote favorable effects on lipidic and glycemic profiles , independently from weight reduction .
therefore , cb1 antagonists could represent a new therapeutic option for the treatment of obesity and the comorbidities related to it , when the currently available data will be confirmed by further clinical studies .
Output:
| the prevalence of obesity continues to increase and represents one of the principal causes of cardiovascular morbidity and mortality . after the discovery of a specific receptor of the psychoactive principle of marijuana , the cannabinoid receptors and their endogenous ligands , several studies have demonstrated the role of this system in the control of food intake and energy balance and its overactivity in obesity .
recent studies with the cb1 receptor antagonist rimonabant have demonstrated favorable effects such as a reduction in body weight and waist circumference and an improvement in metabolic factors ( cholesterol , triglycerides , glycemia etc ) .
therefore , the antagonism of the endocannabinoid ( ec ) system , if recent data can be confirmed , could be a new treatment target for high risk overweight or obese patients .
obesity is a growing problem that has epidemic proportions worldwide and is associated with an increased risk of premature death ( 13 ) .
individuals with a central deposition of fats have elevated cardiovascular morbidity and mortality ( including stroke , heart failure and myocardial infarction ) and , because of a growing prevalence not only in adults but also in adolescents , it was reclassified in aha guidelines as a major modifiable risk factor for coronary heart disease ( 4 , 5 ) .
although first choice therapy in obesity is based on correcting lifestyle ( diet and physical activity ) in patients with abdominal obesity and high cardiovascular risk and diabetes , often it is necessary to use drugs which reduce the risks .
the ec system represents a new target for weight control and the improvement of lipid and glycemic metabolism ( 6 , 7 ) . |
PubmedSumm118787 | ***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 august 2008 , vesicle fluid specimens were collected from 2 children and 1 parent with hfmd at the central hospital of seinjoki , southern ostrobothnia .
specimens were sent to the department of virology , university of turku , for identification of the causative agent .
after detection of cva6 in these index cases , the virus was also found in specimens obtained from the pirkanmaa hospital district ( tampere ) , turku university hospital ( turku ) , pori central hospital ( pori ) , and central - ostrobothnia central hospital ( kokkola ) ( table ) . * cva6 , coxsackievirus a6 ; vp1 , virus protein 1 ; rt - pcr , reverse transcriptase
pcr ; ncr , noncoding region ; hfmd , hand , foot , and mouth disease ; pos , positive ; neg , negative ; na , not available ; nd , not done ; nr , no result ( vp1 sequencing was attempted without result ) .
nucleic acids were extracted from specimens by using the nuclisens easymag automated extractor ( biomrieux , boxtel , the netherlands ) . when the extracts were analyzed for enteroviruses by using real - time reverse transcriptase
pcr ( rt - pcr ) specific for the 5 noncoding region ( ncr ) of picornaviruses ( 4 ) , amplicons with melting points indistinguishable from each other and typical to enteroviruses were obtained . to identify the enterovirus type in the specimens , rt - pcr , specific for a partial sequence of the viral protein 1 ( vp1 ) region ,
was performed by using the consensus - degenerate hybrid oligonucleotide ( codehop ) primers ( bioinformatics.weizmann.ac.il/blocks/codehop.html ) ( 5 ) .
the amplicons were separated by agarose gel electrophoresis , purified with the qiaquick pcr purification kit ( qiagen , hilden , germany ) , and sequenced in the dna sequencing service laboratory of the turku centre for biotechnology .
the virus type in the 3 index specimens , 3 samples of vesicular fluids , and 1 throat swab was successfully identified with sequencing and blast ( www.ncbi.nlm.gov/blast ) analysis as cva6 .
phylogenetic relationships of the sequences were examined by using cva6 ( gdula strain ) , cva16 ( g10 ) , and enterovirus 71 ( brcr ) prototype strains as well as selected clinical cva6 isolates obtained from genbank .
sequence alignments were generated with the clustalw program ( www.ebi.ac.uk/clustalw ) , and the phylogenetic tree was computed by using the jukes - cantor algorithm and the neighbor - joining method .
phylogenetic analyses were conducted by using mega4 software ( www.megasoftware.net ) and the bootstrap consensus tree inferred from 1,000 replicates ( 6 ) ( figure 2 ) .
phylogenetic analysis of coxsackievirus ( cv ) a6 partial ( 289 bp ) viral protein 1 sequences showing the relationships between the recent clinical cva6 samples isolated in finland ( triangles ) , selected cva6 isolates from genbank , and prototypes of cva6 , cva16 , and enterovirus ( ev ) 71 .
phylogenetic analysis placed all cva6 strains from the hfmd outbreak in 1 cluster ( 97%100% identity ) , whereas the nucleotide identities between those isolates and cva6 prototype strains gdula , cav16 , g-10 , and enterovirus 71 brcr were 82.5%83.2% , 55.6%56.6% , and 55.6%57.3% , respectively .
the closest preceding cva6 strain was isolated from cerebrospinal fluid in the united kingdom in 2007 and had 92%94% nucleotide identity with the strains described here ( 7 ) . to improve the detection of the novel cva6 strains in clinical specimens , we designed specific vp1 primers from the aligned sequences .
cva6vp1 reverse primer ( 5-actcgctgtgtgatgaatcg-3 ) and cva6vp1 forward primer ( 5-cgtcaaagcgcatgtatgtt-3 ) generated a 199-bp amplicon .
first , cdna was synthesized in a 20-l reaction mixture containing 1 mol / l cva6vp1 reverse primer , 2.5 mmol / l of each dntp , 20 u revertaid h minus m - mulv reverse transcriptase ( fermentas , st .
leon - rot , germany ) , reaction buffer ( fermentas ) , 4 u ribolock rnase inhibitor ( fermentas ) , and 5 l rna incubated at 42c for 1 h. then , 5 l of cdna was added to 20 l of master mixture containing 0.4 mol / l each of the cva6vp1 primers and maxima sybr green qpcr master mix ( fermentas ) .
pcr with melting curve analysis was performed in a rotor - gene 6000 real - time instrument ( corbett research , mortlake , victoria , australia ) by using the following cycling conditions : initial denaturation at 95c for 10 min , 45 cycles at 95c for 15 s , 60c for 30 s , and at 72c for 45 s , followed by generation of melting curve from 72c to 95c with temperature increments of 0.5c / s .
partial 5 ncr sequence of the strains in clinical specimens was determined as described ( 4 ) and compared with the known sequences by using blast ( http://blast.ncbi.nlm.nih.gov/blast.cgi ) . during autumn 2008 , a total of 47 acute - phase specimens , including 12 vesicle fluid samples , 23 throat swabs , 2 tracheal aspirates , 5 fecal samples , and 5 cerebrospinal fluid specimens from 43 patients yielded amplicons with similar melting points as the originally identified cva6 strains in 5 ncr rt - pcr .
all specimens were subjected to the specific cva6-vp1 real - time rt - pcr , and a positive result was obtained for 11 vesicle fluid samples , 14 throat swabs , 2 tracheal aspirates , and 4 fecal samples ( table ) .
the virus in 1 throat swab was identified as cva6 from the result of 5 ncr sequencing alone .
none of the cva6-positive specimens were positive by an rt - pcr assay with cva16- and ev71-specific primers ( 8) .
attempts to cultivate the virus from 8 cva6 rt - pcr - positive specimens were unsuccessful , whereas the prototype strain could be propagated in rhabdomyosarcoma cells .
onychomadesis was 1 characteristic feature in patients during this hfmd outbreak ; parents and clinicians reported that their children shed fingernails and/or toenails within 12 months after hfmd ( figure 1 ) .
only a few published reports of nail matrix arrest in children with a clinical history of hfmd exist in the medical literature ( 911 ) .
we obtained shed nails from 2 siblings who had hfmd 8 weeks before the nail shedding .
the nail fragments were stored at 70c for a few weeks and treated with proteinase k before nucleic acid extraction .
the virus in one of them was identified as cva6 by the specific rt - pcr and yielded a 5 ncr sequence that was similar to the novel cva6 strains .
enterovirus cva6 was a primary pathogen associated with hfmd during a nationwide outbreak in finland in autumn of 2008 .
hfmd epidemics have primarily been associated with cva16 or enterovirus 71 infections ; those caused by enterovirus 71 have occurred more frequently in southeast asia and australia in recent years ( 12 ) .
reportedly , cva10 has been found in minor outbreaks ; other coxsackievirus a types have been found in only sporadic cases of hfmd ( 2,3 ) . in general , cva6 infections have been seldom detected and mostly in association with herpangina ( 13,14 ) . in finland , cva6 has been identified only on 4 occasions over 8 years during enterovirus surveillance from 2000 to 2007 ( 15 ) .
although the codehop primers were elementary for rapid genotyping of the novel cva6 strains , we identified more viruses with the designated cva6-vp1 specific primers .
onychomadesis was a hallmark of this hfmd outbreak . to our surprise , we detected cva6 also in a fragment of shed nail .
the same virus could have given rise to the outbreak in spain in 2008 ( 10 ) .
this study demonstrates that cva6 , in addition to cva16 and enterovirus 71 , may be emerging as a primary cause of hfmd .
Output:
| during fall 2008 , an outbreak of hand , foot , and mouth disease ( hfmd ) with onychomadesis ( nail shedding ) as a common feature occurred in finland .
we identified an unusual enterovirus type , coxsackievirus a6 ( cva6 ) , as the causative agent .
cva6 infections may be emerging as a new and major cause of epidemic hfmd . |
PubmedSumm118788 | ***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: molecular
dynamics ( md ) simulations are commonly used for ( a ) studying
dynamics of protein structures , ( b ) protein structure prediction ,
and ( c ) calculating thermodynamic properties such as free energies ,
enthalpy , and entropy of conformational states of proteins .
all - atom cartesian md simulations is a classical mechanics based
toolkit using cartesian coordinates as degrees of freedom .
the cartesian
md method is used widely for calculating statistical and thermodynamic
properties of materials and biomaterials .
one of the attractive features
of the cartesian all - atom dynamics model which uses absolute coordinates
is its mathematical simplicity .
there has been extensive development
of all - atom cartesian dynamics algorithms for thermostats and simulation
ensembles such as constant temperature ( nvt ) , constant pressure ( npt ) ,
and constant stress ( grand canonical ensemble ) .
the thermodynamic properties calculated from these ensemble
simulations can be directly compared with experimental measurements .
additionally , constraints and/or bias potentials are often used in
cartesian md to increase the time step size , enhance conformational
sampling , and simulate large - scale conformational changes .
the addition
of these constraints into the cartesian dynamics makes the equations
of motion differential algebraic , requiring differential - algebraic
equation solvers that can adversely impact simulation robustness and
complexity .
bond length , bond angle , and torsion angle ( bat )
relative coordinates are more natural than cartesian absolute coordinates
for describing the bonded structure of proteins .
md simulations in
bat coordinates are referred to as internal coordinate md ( icmd ) methods .
in icmd models of proteins ,
degrees of freedom that are nonessential
for effecting large scale conformational changes in proteins , such
as high frequency bond length degrees of freedom , can be constrained
by simply excluding them from the model . not only do the resulting icmd models have
fewer number of degrees of freedom , but they also retain the simpler
structure of ordinary differential equations instead of the more complex
differential - algebraic structure required for constrained cartesian
models . other advantages of icmd are the following:1.the low - frequency
torsional coordinates
allow larger time steps for integration of the equations of motion.2.conformational search is
more effective
in the low frequency torsional degrees of freedom and leads to significant conformational changes.3.enhanced sampling methods are more
effective when performed in torsional space.4.the six translation and orientation
degrees of freedom for a molecule are explicit coordinates rather
than implicit as in cartesian models .
this is useful when calculating
the conformational entropy using quasi - harmonic analysis.5.they provide a large range
of options
for selecting and controlling the granularity of the dynamics model.6.fixman potential corrections
for constraint - induced biases in the partition
function are easier to apply .
the low - frequency
torsional coordinates
allow larger time steps for integration of the equations of motion .
conformational search is
more effective
in the low frequency torsional degrees of freedom and leads to significant conformational changes .
the six translation and orientation
degrees of freedom for a molecule are explicit coordinates rather
than implicit as in cartesian models .
they provide a large range
of options
for selecting and controlling the granularity of the dynamics model .
fixman potential corrections
for constraint - induced biases in the partition
function are easier to apply .
the ability of the icmd simulation methods to control
the granularity of the dynamics model makes them highly suitable for
the development of multiscale methods and strategies for the simulation
of protein macromolecular complexes and polymeric materials .
our vision
is to develop a robust and advanced icmd method that capitalizes on
the inherent advantages of icmd , and to use these methods to develop
a comprehensive icmd simulation toolkit for tackling important problems
in structural biology .
the coupled nature of the icmd coordinates
and the higher complexity of icmd models however demands far more
sophisticated mathematical techniques and algorithms .
torsional md is a well - known example of
an icmd method that constrains
all bond lengths and bond angles .
many research groups have used the
torsional md method for simulating the dynamics of peptides and proteins in addition to clarifying the stubborn challenges
associated with the torsional md methods .
the wider usage of torsional md methods has been
hampered by serious bottlenecks that slowed their progress and viability
of icmd methods as a structural biology tool .
two long - standing concerns
have been ( a ) the mathematical and computational complexity of the
equations of motion associated with the icmd models and ( b ) the increased
rigidity in the torsional md dynamics resulting from keeping the bond
lengths and angles constrained , affecting the transition barriers
and probability density functions of states in a protein .
when
all the bond lengths and bond angles are constrained in torsional
md , the equations of motion in the dihedral angle space become computationally
expensive with the solution scaling as the cubic power of the number
of torsion degrees of freedom .
this has been a major bottleneck that
stunted the use and growth of icmd methods .
euler inverse mass operator ( gneimo ) method that is
based on the wealth of mathematical theory and analysis using spatial operator algebra techniques originally developed
for spacecraft and robot dynamics domains .
there has been a considerable amount of research over the years
on the development of the spatial operator algebra methods for the analysis of robot multibody
system dynamics .
the key insights that have been developed included
analytical techniques for the factorization and inversion of the mass
matrix for tree - topology systems .
these techniques have opened up
the opportunities to revisit and advance torsional md simulations
and make it computationally accessible to the wider community .
our
spatial operator algebra based icmd algorithm for solving the equations
of motion was the first to overcome the icmd computational cost bottleneck
by reducing costs to being just linearly , instead of cubically , proportional
to the number of degrees of freedom .
this low cost
algorithm has been adopted by other groups to implement torsional
md capability .
the gneimo method has been applied
to study a wide variety of structural biology problems such as protein
folding , protein structure refinement , and domain motion in proteins .
this algorithm is now being used routinely in refining
nmr structures ( in the software called cyana ) and x - ray crystal structures
( in the software called nih - xplor ) . however , these two applications
require only short time scale dynamics and do not require calculation
of accurate thermodynamic properties from simulations .
although
the first challenge was eliminated making torsional md
simulations computationally feasible with the spatial operator algebra
based solution , the second bottleneck arising from the rigidity of
the model still persisted .
the increased rigidity of the dynamic model
stemming from freezing degrees of freedom led to fewer dihedral transitions
and to systematic errors in the probability density functions for
proteins and peptides .
researchers have observed that the use of rigid
constraints in both bond lengths and bond angles in the torsional
md simulations alters the potential energy surface and the free energy
surface of the system compared with unconstrained md simulations . addressing the rigidity of the dynamics model imposed
in the torsional md simulations , fixman in the 1970s proposed a compensating
potential that rigorously corrects for treating stiff and uncoupled
bond angles as rigid in the icmd model , and generates a partition
function that gives probability density functions closer to that of
all - atom cartesian simulations .
while the fixman potential removes such biases for those bond angles
that are stiff , it remained intractable and hence not tested for larger
branched molecules . by developing a spatial operator algebra based
general purpose and low - cost computational method to calculate the
fixman potential for all linear and branched molecules , we have solved the longstanding problem of using the fixman potential
in icmd simulations to remove constraint - induced biases in thermodynamic
properties and the probability density function .
our studies verify
that , as predicted , the inclusion of the fixman potential recovers
the equilibrium probability density function of the conformational
states , the transition barrier crossing rates , and the free energy
surface for serial and branched molecules . to the best of our knowledge , this is the first time that the fixman
potential has been used for icmd of large and realistic branched polymers . overcoming the two long - standing bottlenecks along with several
theoretical and algorithmic advances in the gneimo icmd method made
in the past five years
has led to a robust long time scale icmd simulation
method and an associated software package for use to study protein
structural dynamics .
the highlights of these methods
are described in section 2 , and the highlights
of the results for several protein simulation applications and their
comparison to experimental findings are given in section 3 .
the current state of the icmd methods and the
areas that need further development are discussed in section 4 .
the icmd
method is a molecular dynamics simulation method performed
in bat coordinates also known as internal coordinates .
the gneimo
method is a generalized icmd method based on spatial operator algebra ,
for performing multibody dynamics of macromolecules .
constraints on
the high frequency bond lengths can be placed in the gneimo method
to perform icmd simulations with the bond angles and torsion angles
as degrees of freedom . if both the bond lengths and bond angles are
kept rigid , the resulting torsional md method is also supported by
gneimo . in the gneimo torsional md method ,
the bond length and bond
angle degrees of freedom are treated as rigid and the macromolecule
of tree topology is modeled as a collection of rigid bodies ( of varied
sizes ) connected by flexible hinges .
the rigid bodies also known as clusters can vary in size and shape ranging from a single
atom to a methyl group , or a helix or an entire domain of a protein .
however , these hinges have one to six degrees of freedom ,
with the one degree of freedom being just the torsion angle .
when
the hinge has six degrees of freedom , it allows the bond stretch ,
bond angle bending , and torsion about the bond connecting the clusters .
the default cluster model of proteins in the gneimo method is shown
in figure 1 . when the bond lengths and
bond angles are treated as rigid
, the
equations of motion in icmd become coupled and are shown in eq 11where is the vector of the generalized
coordinates ( e.g. , torsional angles ) , denotes
the vector of generalized forces
( e.g. , torques ) , denotes the mass matrix ( moment of inertia
tensor ) , and includes
the velocity dependent coriolis
forces .
the dynamics of motion is obtained by solving eq 1 for the acceleration and integrating them
to obtain new velocities and coordinates . with conventional algorithms ,
the equations of motion involve calculating the inverse of the dense
mass matrix that scales as the cubic power of the number of degrees
of freedom .
the gneimo method uses a spatial
operator algebra based method to derive an analytical expression for
the inverse of the mass matrix followed by the following expression
for 2the , , , etc .
, terms
in the above expression are
associated with mass matrix related factorizations and are described
in detail in refs ( 5 and 19 ) .
standard clustering
scheme used for torsional md in gneimo shown
for the tripeptide ala - tyr - ala .
the rigid clusters are shown in a
single color , and these clustered atoms move together as a single
unit . the gray rods and arrows represent hinges connecting two clusters .
the expression on the
right can be evaluated using recursive algorithms
whose cost scales just linearly with the number of degrees of freedom
and thus provides a computationally tractable method for solving the
equations .
this recursive algorithm described in detail in ref ( 5 ) avoids the computationally
intensive inversion of the dense mass matrix shown in the matrix equation
in eq 1 .
we further extended this method to
simulate the canonical n , v , t ensemble with constant temperature dynamics using the
nos hoover thermostat method .
hoover
icmd method are given below.34 here is the additional
frictional force term
due to the canonical ensemble which is
dependent on , the dynamic variable representing the thermostat ,
is the mass parameter of the thermostat , t is
the instantaneous temperature , and tb is the
thermostat temperature . since the gneimo nos
hoover
equations of motion shown above are similar to the equations of motion
in eq 1 , all the spatial operator equations
and factorization discussed in ref ( 5 ) hold good for these equations as well . the nos
hoover
thermostat mass parameter was optimized to be 10 times the
time step size for torsional md simulations .
the accuracy and stability of the gneimo torsional md simulations
were measured by the conservation of the total hamiltonian and the
extent of fluctuations in the temperature .
other
research groups such as brooks and co - workers and schweiters and co - workers
adapted the gneimo algorithm into charmm and nih - xplor programs for
icmd simulations .
however , the systematic
biases in the probability density functions
calculated from icmd simulations arising from the rigidity of the
model remain to be solved .
to rigorously correct for the systematic
biases in the probability density function caused by treating stiff
bond angles as rigid , fixman proposed a compensating potential of
the form5where denotes the
mass matrix in the full bat
coordinates , q0 the coordinates for the
frozen degrees of freedom , k the boltzmann constant ,
and t the temperature . while the fixman potential removes such biases , it was computationally
intractable for generalized branched molecules and hence remained
untested and unused for several decades for icmd simulations , except
for small model systems such as c4 or c5 .
we derived a spatial operator algebra based
algorithm that calculates the fixman potential with just 24% additional
cost in the computation time .
this method which we
call gneimo - fixman is rigorous , general purpose , low - cost , and applicable
to general linear and branched systems with little additional cost .
more significantly , the gneimo - fixman method is also able to compute
the partial derivatives of the fixman potential .
these partial derivatives
define the additional forces , i.e. , the fixman torque , to be applied
within constrained md simulations .
this makes it feasible to use the
fixman potential during the torsional md simulations and test the
effect of the fixman potential on recovering the accuracy of the probability
density functions and the dihedral transition rates . to study the effectiveness of
the fixman potential in recovering the thermodynamic probability density
function of torsion angles , we performed torsional md simulations
with langevin force for various linear and branched molecular systems
without force fields .
the effect of the fixman potential can be most
clearly seen by comparing the probability density functions calculated
from torsional md simulations with the fixman potential to the probability
density functions calculated from unconstrained cartesian md simulations .
figure 2 shows the joint probability distribution function
of the two main chain torsion angles in alanine dipeptide .
it is seen
from the plots that the torsional md introduces biases in the joint
probability density function that are removed when the torsional md
simulations are performed with the fixman potential and the torques .
the magnitude of the fixman potential is much smaller in comparison
to the potential energy from the all - atom force field .
there are some
bond angles in the protein that are weakly coupled to the dihedrals
and the nonbond forces while other bond angles such as backbone bond
angles that show strong coupling to the dihedrals and the nonbond
forces .
although the fixman potential corrects for the errors in the
probability density function stemming from treating stiff and uncoupled
bond angles as rigid , it does not do so for soft bond angles that
couple to the torsion angles or the nonbond interactions .
there
are two approaches for eliminating the bias in the potential energy
surface imposed by treating the bond angles that are coupled to torsions
and nonbond interactions , as rigid .
the first approach is to open
up some of the bond angles and treat them as movable degrees of freedom
in the icmd simulations .
this approach reduces rigidity
and the error in probability density function and transition rates ,
with little impact on time step size .
the second approach is to use
correction torsional potentials that compensate for the rigidity in
the coupled bond angles to recover the probability density function .
examples of this approach are the ecepp family of force fields or icmff that correct the torsional angle potential
for all of the bond angles .
the icmff corrects the force constants
used for the torsional angle potentials by refitting the torsional
energy curve obtained from the rigid model to the torsional energy
curve calculated using the flexible model .
the force constants thus
obtained will reproduce the torsion energy barriers of the flexible
cartesian model .
chen et al . showed that this method enhances the
number of dihedral transitions during the torsional md simulations .
the possible caveat with this method is that it is not rigorous and
is system specific .
the icmff has been tested for alanine dipeptide
and remains to be tested for larger systems . in summary , it is necessary
to treat the bond angles that show strong coupling to torsion angles
as flexible degrees of freedom in order to achieve thermodynamic accuracy
in the probability density function . however , this is not required
if the torsional md simulations are used for structure prediction
applications .
this is because the goal in structure prediction applications ,
such as refining the loop structures in proteins , is to enrich the
native ensemble by widening the conformational sampling and generally
not in recovering the accuracy of the partition function of the cartesian
md simulations .
besides the two
major challenges ( described above ) that have hampered icmd method
development , there were other developments that were required to make
the icmd method robust and suitable for long time scale simulations .
several research groups have shown that constrained icmd models are
not the limiting case of stiff cartesian models . to address the differences between constrained icmd models and cartesian
models of the molecule
, we showed that the application of the conventional
equipartition theorem that is based on the cartesian model to the
icmd model in internal coordinates does not yield an equipartition
principle analogous to that for cartesian models .
instead , the ensemble
averages involve configuration dependent coupled coordinates , that
are not easy to interpret or use .
therefore , we introduced a coordinate
transformation to modal coordinates that transforms the system s
kinetic energy into a decoupled form similar to that for cartesian
models .
additionally , we showed that using the modal velocity
coordinates one can derive an equipartition principle for the icmd
model that is analogous to the one for cartesian models .
this principle
holds even though the modal coordinates are not canonical coordinates
in the hamiltonian sense . the equipartition principle based on modal
coordinates provides a method for the thermodynamically correct initialization
of velocities in icmd simulations .
joint probability
distribution function of the two backbone torsion
angles in alanine dipeptide : ( a ) cartesian simulations ; ( b ) icmd simulations ;
( c ) icmd + fixman simulations .
the bin size for each axis is d
= 18. material : reprinted with permission from ref ( 18 ) .
we have
developed a modular software package called gneimosim for efficient implementation of icmd simulations .
gneimosim is quite possibly the first software package
to include advanced features such as the icmd equipartition principle
and methods for including the fixman potential to eliminate systematic
statistical biases introduced by the use of hard constraints .
moreover ,
gneimosim s architecture allows it to be extended and easily
interfaced with third party force field packages for icmd simulations .
the availability of a comprehensive
python interface to the underlying c++ classes and their methods provides
a powerful and versatile mechanism for users to develop simulation
scripts to configure the simulation as well as to control the simulation
flow .
the alpha version of the gneimosim software is available
for use for the research community at http://dartslab.jpl.nasa.gov/gneimo/index.php . in figure 3
, the blue line shows the
average run time for a simulation for the start - up and solution of
the equations of motion in the gneimo algorithm without using a force
field .
it shows the effective linear scaling of the dynamics equations
solver cost for the gneimo method in gneimosim .
the average run time
for calculating the forces using openmm with gbsa ( on a gpu ) and using
lammps and rosetta force fields on a cpu are shown in yellow , red ,
and green lines , respectively .
the cost of running the equations of
motion solver in gneimo is equivalent to the force field cost of using
the amber force field with the generalized born solvation module on
gpu using the openmm force field engine .
however , for larger systems ,
the cost of the gneimo equations of motion solver will have a linear
dependence while the cost of the calculation of forces will show a
higher order increase in computational time .
additionally , the increase
in computational time for icmd is compensated to an extent by the
ability to take larger time steps than are possible in a cartesian
simulation .
we have implemented
in gneimosim several methods that are routinely used in md simulations
such as1.advanced
integrators including runge
kutta ,
lobatto , adaptive cvode , and verlet integrators for stable long time
scale ( microseconds ) torsional md simulations.2.an adaptation
of the generalized born
solvation method ( gbsa ) for implicit solvation.3.support for multiple molecules of any
type , including explicit solvent.4.a temperature - based replica - exchange
( remd ) method in which temperatures may
be switched randomly or probabilistically using the metropolis algorithm.5.periodic boundary conditions
for simulations
with explicit water.6.support for standard cartesian simulations
for comparison.7.user
defined harmonic distance restraints
between pairs of atoms.8.more recently , we have added langevin
dynamics and accelerated md ( amd ) methods to gneimosim .
kutta ,
lobatto , adaptive cvode , and verlet integrators for stable long time
scale ( microseconds ) torsional md simulations .
an adaptation
of the generalized born
solvation method ( gbsa ) for implicit solvation .
a temperature - based replica - exchange
( remd ) method in which temperatures may
be switched randomly or probabilistically using the metropolis algorithm .
more recently , we have added langevin
dynamics and accelerated md ( amd ) methods to gneimosim .
average
run times per step for the gneimosim simulation using different
force fields .
the
bat coordinates are natural coordinates to describe a bonded system
like proteins and polymers .
they also lend themselves readily to freezing
and thawing any internal coordinate degree of freedom .
for example ,
many torsional degrees of freedom can be kept constrained during dynamics
such as freezing a whole helixin a protein structure , if needed .
this
freeze and thaw can be done at the start of the simulation or during
the course of the md simulations in the gneimo icmd method .
we refer
to the freeze and thaw technique on the fly during the dynamics simulations
as dynamic clustering .
the dynamic clustering scheme can be applied automatically on the
basis of user specified criteria to freeze and thaw internal coordinate
degrees of freedom .
the default clustering scheme for the gneimo torsional
md treats all the torsions of the backbone and main chain as degrees
of freedom .
all - torsion md simulations may not be adequate for simulating
long time scale events such as large conformational changes in proteins .
adaptable clustering strategies that allow change in the cluster model
of the protein during the simulations are more suitable for simulating
large conformational changes .
wagner et al . used criteria to freeze secondary
structure elements when performing folding simulations at high temperature
replicas and allow them to thaw at lower temperature replicas .
however , it should be noted that , since the
freeze and thaw mechanism can alter the pathway of the process being
simulated , it is advisable to use this method for conformational search
purposes only . other criterion to freeze or thaw a degree of freedom
is by using an upper threshold for the velocity , a hinge can be treated
as flexible if its velocity stays closer to the threshold velocity .
this ensures that torsions that undergo significant motion are not
treated as rigid . additionally , monitoring the accumulation of stress
forces at a hinge that is treated rigid
we have
used the freeze and thaw strategy to fold four proteins starting from
their respective extended structure .
the secondary structure elements
were predicted using sequence information and built into the extended
structure .
gneimo torsional md with the replica exchange method was
used to run the folding simulations . the adaptive time step cvode integrator using the adams
the cvode adaptive
integrator ensures stable simulations while allowing rapid conformational
sampling of clustered rigid bodies , by adjusting the time step size
to avoid clashes that destabilize the md simulations . using the md
trajectory of the b domain of staphylococcal protein a , we calculated
the population density histogram shown in figure 4 .
this figure also shows the corresponding representative
structures from each of the conformational clusters .
the x - axis is the root - mean - square deviation ( rmsd ) of the backbone atom
coordinates from the crystal structure .
we used 12 temperature replicas ranging from
300 to 1050 k. the folding process begins with the extended structure
with just the predicted helices using secondary structure prediction
methods .
initially , a small number of interhelical contacts are made
that collapses the structure to a rmsd range of 1216 .
at 811 ,
slightly incorrect protein topologies are explored
that finally fold to the correct topology below 7 .
this example
demonstrates the rapid conformational sampling realized using the
dynamic clustering strategy .
large scale domain
motion caused by the low frequency modes in a protein are often difficult
to capture with cartesian md simulations .
the conformational transitions
between the substates are often affected by long time scale and rare
events difficult to capture within the relatively short ( hundreds
of nanoseconds ) time scale md simulations .
enhanced sampling methods
are therefore often used to simulate the conformational transitions
in proteins .
some of the enhanced sampling
methods require explicit knowledge of the conformations for which
the transitions are being simulated , and therefore not readily applicable
to unknown systems .
the temperature based remd method when used with
cartesian md simulations often leads to unraveling and reforming of
secondary structure motifs .
thus , the transitions are wasted in high
frequency modes and the extra thermal energy is not focused on searching
in the low frequency modes .
we studied the use of remd with gneimo
torsional md simulations to see how effective they are in conformational
search in two highly flexible proteins , namely , fasciculin and calmodulin .
calmodulin is a calcium signaling protein that
belongs to the ef - hand family of proteins .
the three - dimensional structure
of calmodulin consists of two domains , namely , the amino terminus
( n - terminus ) domain and the carboxy - terminus ( c - terminus ) domain ,
that are connected by a long helical stretch .
calmodulin is a dynamic
protein that exhibits major conformational changes in response to
calcium binding as revealed by nmr studies . upon binding
to calcium ,
calmodulin samples a large ensemble of structures that
allows it to bind to a wide range of proteins .
there are several experimental
studies on the dynamics and conformational changes in calmodulin .
these studies show that there are two major steps involved in the
conformational changes : ( 1 ) upon removal of the bound calcium , the
central helix that connects the carboxy terminal domain and the amino
terminal domain collapses followed by ( 2 ) the dynamics of the n - terminus
domain relative to the static c - terminus domain .
cartesian md simulations in explicit solvent showed the collapse
of the central helix connecting the two domains but could not map
the entire dynamics ensemble obtained from the nmr study .
the gneimo - remd simulations with no bias potential were performed
on the entire calmodulin protein .
the trajectory showed conformational
sampling of the collapse of the central helix , and the sampling of
various conformations resulting from the relative reorientation of
the two domains .
although the collapse was observed in the cartesian
md , the flexibility of the n - terminus domain was observed only in
the gneimo - remd simulations .
comparison of the ensemble of conformations
of the carboxy terminus domain to the ensemble of conformations from
nmr experiments is shown in figure 5 .
it is
seen that the gneimo conformations ( shown in blue in figure 5 ) cover most of the nmr conformations .
backbone crmsd
histogram of a dynamic clustering
replica - exchange simulation of 1bdd , beginning from an extended conformation
containing predicted secondary structure elements with representative
structures .
overlay of the conformations
sampled in the gneimo - remd torsional
md simulations ( shown in blue ) of calmodulin without calcium , to the
nmr structures pdb i d : 1dmo ( shown in gold ) .
quantitative comparison of the average hydrogen bond distances
between residues showing hydrogen bonds in the nmr structures ( pdb i d : 1dmo ) to those in the gneimo - generated trajectories
shows that about half of the average distances calculated fall within
one standard deviation of the corresponding distances in the nmr structures .
gneimo torsional md simulations on proteins such as crambin and bpti
at 310 k have shown that the correlations in the torsional motions
of residues that are farther apart in space can be captured in a shorter
simulation time scale than with cartesian md simulations .
for example ,
in the case of bpti , analysis of correlation in the backbone torsion
angles of residues in two loops connected
by a disulfide bond was shown to be strong in the millisecond level
simulations of shaw and co - workers .
we
have shown that we could capture the torsional angle correlations
between residues 9 to 18 and residues 35 to 40 in 100 ns of nvt gneimo
torsional md simulations at 310 k. the
gneimo algorithm has been implemented in the software package
cyana for nmr structure refinement and
in nih - xplor for x - ray crystal structure refinement . brooks and co - workers have tested torsional md simulations
based on the gneimo algorithm for few proteins . however
, this method has not been tested for refining protein
homology models of lower accuracy compared to their respective crystal
structures . due to the large number of protein structures of similar
proteins available in the protein data bank ,
homology or template
based modeling of related protein sequences has been shown to be the
most feasible and accurate method of predicting protein structures .
however , the target sequence has to have a > 60%
sequence similarity to the template crystal structure .
the accuracy
of the model derived using homology modeling methods depends on the
sequence similarity between the template and the target .
there is
an increasing need for high throughput computational methods that
refine low accuracy homology models .
using
cartesian md simulation methods leads to refined structures only when
used with restraints with the choice of restraints remaining
arbitrary and system dependent and hence difficult to automate .
starting from the homology based models , robust structure refinement
methods are important to derive high useful accuracy models .
an efficient conformational sampling method and an accurate energy
function to identify the native structure are the two important components
of a structure refinement algorithm .
we have evaluated the usefulness
of the conformational sampling afforded by gneimo - remd with the generalized
born solvation method in enriching the refined structures compared
to the starting decoy .
the gneimo - remd method
leads to a refinement of up to 1.3 for 28 out of 30 casp target
proteins .
these torsional md simulations using gneimo were done without
any experimental information as restraints .
figure 6 shows the contact map for one target ( t0453 ) as an example
of the refinement using the gneimo method .
figure 6 shows the contact map for refinement of the target protein
t0453 . the contact map shows
far is a given residue in the gneimo refined model from its crystal
structure .
the white color regions indicate the residue positions
that are closer to the native structure than the residues in the deep
red regions .
it is evident from figure 6 that
the gneimo refined structure shows significant refinement in the packing
of the loop structure against the core of the protein .
the long - range
contacts between the loop residues 30 to 40 to those residues between
40 and 60 improve remarkably from 14 to 16 to 2 to 4 ,
as seen in figure 6 .
the
contact map shows the distance to the decoy structure , and the contact
map in the third column shows how far each residue is refined corresponding
to the native structure .
while the gneimo method leads to substantial refinement in
the
loop packing , the unconstrained cartesian remd method shows unraveling
and reformation of secondary structure elements and hence is less
effective in conformational search .
thus , starting from homology models
of varying accuracy , the gneimo method shows improvement in structure
refinement without unraveling the structures .
the overall extent of
refinement across many targets was modest and needs further improvement .
the icmd simulation
method is not a replacement for the cartesian
md method .
we envision developing an icmd simulation method to perform
md simulations in bond , angle , and torsion ( bat ) coordinate systems .
such a md simulation method is highly suitable for selecting and controlling
the granularity of the dynamics model of proteins and polymers , and
is a foundation for the development of multiscale simulation methods
for the simulation of protein macromolecular complexes .
the multiscale
icmd simulation method can also be used for real space refinement
of structural model fitting to low resolution crystallography or electron
microscopy data of large protein complexes .
currently ,
studies of the large scale dynamics that govern protein function commonly
use all - atom cartesian md simulations , often with geometric constraints .
such geometric constraints can adversely impact the integration time - step
size and the stability of the dynamics . on the other hand ,
our recent theoretical developments based
on spatial operator algebra have led to a robust long time scale icmd
simulation method gneimo and associated toolkit known as gneimosim .
we have demonstrated the power of the gneimo icmd technique with applications
to protein domain motion studies and homology model refinement studies .
the results of these applications have shown great promise in the
wider use of this icmd technique .
however , there remain extensions
of the methods that need to be addressed to harness the advantages
of icmd methods to their fullest .
some of the possible extensions
are the following:1.to calculate accurate conformational
entropy using the gneimo torsional md simulation trajectories with
the quasi - harmonic analysis ( qha ) method to improve the accuracy while
correctly including traditionally difficult metric tensor correction
terms.2.the second advancement in icmd simulations
will be to extend the icmd simulation method to allow movement of
certain bond angles that show strong coupling to the dihedral angles .
for example , it has been shown that the bond angle hinged on the c
atoms of a protein have strong coupling to the backbone dihedral angles .
we will extend the gneimo icmd method to free up desired bond angle
degrees of freedom .
this will lead to a comprehensive suite of hybrid
icmd models that bridge the wide gap between coarse grain torsional
md and fine grain all - atom md models .
these hybrid icmd models , with
all bond angles open , can also be used for accurately calculating
conformational entropy as discussed here.3.gneimosim software has enhanced sampling methods such as langevin
dynamics , replica exchange method implemented .
gneimo can be readily
combined with other enhanced sampling techniques such as steered md ,
umbrella sampling , or accelerated md ( amd ) to name a few . to calculate accurate conformational
entropy using the gneimo torsional md simulation trajectories with
the quasi - harmonic analysis ( qha ) method to improve the accuracy while
correctly including traditionally difficult metric tensor correction
terms .
the second advancement in icmd simulations
will be to extend the icmd simulation method to allow movement of
certain bond angles that show strong coupling to the dihedral angles .
for example , it has been shown that the bond angle hinged on the c
atoms of a protein have strong coupling to the backbone dihedral angles .
we will extend the gneimo icmd method to free up desired bond angle
degrees of freedom .
this will lead to a comprehensive suite of hybrid
icmd models that bridge the wide gap between coarse grain torsional
md and fine grain all - atom md models .
these hybrid icmd models , with
all bond angles open , can also be used for accurately calculating
conformational entropy as discussed here .
gneimosim software has enhanced sampling methods such as langevin
dynamics , replica exchange method implemented .
gneimo can be readily
combined with other enhanced sampling techniques such as steered md ,
umbrella sampling , or accelerated md ( amd ) to name a few . with these improvements
,
the gneimo method will be useful for applications
to large protein dynamics simulations with explicit solvent .
the gneimo
method can be used with any type of force field such as an all - atom
force field or a coarse grain force field .
we also envision using
the gneimo torsional md method combined with the torsional monte carlo
method for protein structure prediction applications . in summary ,
the gneimo method offers a comprehensive icmd simulation method that
allows easy coarse graining of the dynamics model ranging from all - atom
to large domains of proteins being treated as clusters .
Output:
| internal coordinates such as bond
lengths , bond angles , and torsion
angles ( bat ) are natural coordinates for describing a bonded molecular
system . however , the molecular dynamics ( md ) simulation methods that
are widely used for proteins , dna , and polymers are based on cartesian
coordinates owing to the mathematical simplicity of the equations
of motion .
however , constraints are often needed with cartesian md
simulations to enhance the conformational sampling .
this makes the
equations of motion in the cartesian coordinates differential - algebraic ,
which adversely impacts the complexity and the robustness of the simulations .
on the other hand ,
constraints can be easily placed in bat coordinates
by removing the degrees of freedom that need to be constrained .
thus ,
the internal coordinate md ( icmd ) offers an attractive alternative
to cartesian coordinate md for developing multiscale md method .
the
torsional md method is a special adaptation of the icmd method , where
all the bond lengths and bond angles are kept rigid .
the advantages
of icmd simulation methods are the longer time step size afforded
by freezing high frequency degrees of freedom and performing a conformational
search in the more important low frequency torsional degrees of freedom .
however , the advancements in the icmd simulations have been slow and
stifled by long - standing mathematical bottlenecks . in this review
,
we summarize the recent mathematical advancements we have made based
on spatial operator algebra , in developing a robust long time scale
icmd simulation toolkit useful for various applications
. we also present
the applications of icmd simulations to study conformational changes
in proteins and protein structure refinement .
we review the advantages
of the icmd simulations over the cartesian simulations when used with
enhanced sampling methods and project the future use of icmd simulations
in protein dynamics . |
PubmedSumm118789 | ***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: amyloidosis defines a group of diseases characterized by extracellular deposition of protein precursorsas insoluble fibrillar aggregates , able to induce both organ dysfunction and/or cellular death .
amyloid fibrils can be identified in biopsy specimens both by their characteristic appearance on electron microscopy and by their ability to bind congo red and thioflavine - t .
they are randomly organized and are approximately 8 - 10 nanometers in diameter . despite a common beta fibrillar structure
, the protein precursors and pathogenetic mechanisms of amyloid fibrils may vary according to the different type of amyloidosis ; amyloid light - chain ( al ) ( primary or immunoglobulin light chain associated ) , amyloid a ( aa ) ( secondary or reactive to chronic inflammation ) and familial amyloidosis ( af ) or heredofamilial .
familial mediterranean fever ( fmf ) , chronic infections ( such as tuberculosis ) , chronic rheumatologic diseases and inflammatory bowel disease are the most frequentetiologies .
kidneys are the most common sites of amyloid deposition in al , aa , and several of hereditary amyloidoses .
the hallmarks of renal amyloidosis are severe proteinuria and progressive renal failure . without treatment ,
amyloidosis - associated kidney disease usually progresses to end - stage renal disease ( esrd ) . in this study
, we retrospectively analyzed clinical features , survival and prognostic markers in aa amyloidosis with renal involvement .
all records of patients who were treated in our in / outpatient clinic of nephrology between january of 2001 and may of 2013 were reviewed for the presence of biopsy - proven aa amyloidosis with renal involvement .
all patients had renal biopsy and aa amyloidosis was confirmed by hematoxylin - eosin , congo red , crystal violet and anti - aa antibody stains .
data were obtained from patients follow - up charts and electronic hospital records , and all patients had to have at least one clinical control after diagnosis .
diagnosis of fmf was confirmed according to criteria 's described by livneh et al . , while other etiologies were reassessed by reviewing past medical records .
date of onset and type of dialysis and causes of death were recorded , if identified .
spss 20.0 software ( spss inc . , chicago , usa ) was used for statistical analysis .
student 's t - test was used for parametric variables and mann - whitney u - test was used for nonparametric variables .
yates correction chi - square test and fisher 's exact test were used for comparison of qualitative data .
survival was estimated by kaplan - meier and log rank ( mantel - cox ) test .
spss 20.0 software ( spss inc . , chicago , usa ) was used for statistical analysis .
student 's t - test was used for parametric variables and mann - whitney u - test was used for nonparametric variables .
yates correction chi - square test and fisher 's exact test were used for comparison of qualitative data .
survival was estimated by kaplan - meier and log rank ( mantel - cox ) test .
mean age at diagnosis was 42.6 14.4 ( range : 17 - 74 ) years .
mean follow - up period was 38.2 37.2 ( 1 - 167 ) months .
fmf ( 37.1% ) and tuberculosis ( 24.7% ) were the most frequent causes , followed by unknown etiology ( 19.8% ) , chronic rheumatologic diseases ( 8.2% ) , chronic obstructive pulmonary diseases ( 6.6% ) and others ( 3.3% ) .
all fmf patients received 1 - 2 mg colchicine for an average of 8.7 6.4 years prior to renal biopsy . compared with fmf ,
patients who had underlying tuberculosis were older ( p = 0.007 ) and had significantly lower levels of albumin ( p = 0.005 ) , higher levels of proteinuria ( p = 0.007 ) and ferritin ( p = 0.035 ) [ table 1 ] .
amyloid deposition was mainly located in the glomerulus showing a mesangial nodular pattern and extraglomerular vessels were involved in 65% of cases .
nephrotic syndrome was the presentation of 47 ( 38.5% ) patients , whereas nonnephrotic proteinuria with and without renal failure was present in 41.5% and 20% of patients , respectively .
the demographic features and laboratory findings at the time of diagnosis sixty - eight ( 56.2% ) needed dialysis treatment during follow - up ( 62 hemodialysis [ hd ] , 6 peritoneal dialysis [ pd ] ) .
mean renal survival was 64.7 6.3 months ( median : 52 11 ) .
renal survival rates at 1 , 2 and 5 years were 81.7% , 67.3% and 46.1% , respectively [ table 2 ] . patients who needed dialysis were significantly older , had higher serum urea , creatinine , phosphorus , intact parathormone , proteinuria and lower estimated glomerular filtration rate ( egfr ) , serum albumin , hemoglobin levels at presentation [ table 3 ] .
a multivariate logistic regression analysis showed that age , serum creatinine and albumin levels were predictors of esrd [ table 4 ] .
etiology was not a significant predictor of requirement for dialysis . during the first 3 months
follow - up period 26 patients ( 21.4% ) were started on dialysis and14 patients died ( nine patients were receiving dialysis ) .
renal and patient survivals were not significantly different between fmf and tuberculosis groups , except for the first 3 months where patients with tuberculosis significantly more frequently required dialysis ( 8% vs. 23% , p = 0.004 ) ; and had a higher mortality rate ( 2.2% vs. 16.6% , p = 0.018 ) .
renal survival time according to etiology and stage of renal failure demographic features and laboratory findings of the patients according to dialysis requirement multivariate logistic regression analysis of the factors that predicts esrd fifty patients ( 41.3% ) died during follow - up period .
survival rates at 1 , 2 and 5 years were 80.7% , 68.2% and 51.3% , respectively [ table 5 ] .
older age , male gender , lower body mass index , egfr , serum albumin and ca levels , shorter time to dialysis , and higher levels of serum phosphorus , intact parathyroid hormone ( ipth ) , ferritin and protein uria were associated with lower odds of patient survival [ table 6 ] .
a multivariate logistic regression analysis indicated that higher serum creatinine ( for creatinine > 1.3 mg / dl , hazard ratio [ hr ] 1.97 , p = 0.019 ; 95% confidence interval [ ci ] 1.1 - 3.5 ) , lower albumin level ( for albumin < 2.6 g / dl , hr 1.87 , p = 0.028 ; 95% ci 1.06 - 3.30 ) , short time to dialysis , dialysis requirement and stage of renal disease were predictors of death [ table 7 , figures 1 and 2 ] .
analysis of survival characteristics according to age groups revealed a dramatically lower life expectancy of patients older than 60 years [ table 8 ] .
patient survival time according to etiology , dialysis requirement and stage of renal failure demographic features , laboratory findings of died and alive patients multivariate logistic regression analysis of the factors that predicts mortality patient survival according to serum albumin level patient survival according to stage of renal disease patients survival time according to age groups mortality of patients who reached to esrd was significantly higher than those who did not ( p = 0.001 ) .
forty - three ( 43/68 , 63.2% ) of all dialyzed patients died , while only 7 ( 13.2% ) of the 53 patients who did not reach to esrd .
mean survival of patients who required dialysis versus who did not were 61.3 8.5 versus 119.1 7.6 months , respectively .
1 , 2 and 5 years survival rates from the start of dialysis were 44.7% , 40.0% and 22.0% compared to 89.2% , 86.3% and 82.7% for patients who did not need dialysis , respectively [ table 5 ] .
mean survival of patients with fmf and tuberculosis were 105.6 12.1 and 66.2 11.6 months , respectively . 1 , 2 and 5 years survival rates of patients with fmf were 92.9% , 82.9% and 62.2% , as compared to 75.8% , 63.1% and 41.5% for patients with tuberculosis , respectively [ table 5 ] .
overall mortality was not significantly different between patients with fmf and tuberculosis , except for greater mortality rate of tuberculosis patients within the first 3 months of follow - up ( p = 0.018 ) .
of 50 patients who died , 9 ( 18% ) were due to chronic nutritional debility , which led to cachexia , malnutrition and infection , 26 ( 52% ) were due to hypotension that led to complications of hd insufficiency such as uremia , hyperkalemia and hypervolemia , and 15 ( 30% ) were due to unidentified causes .
sixty - eight ( 56.2% ) needed dialysis treatment during follow - up ( 62 hemodialysis [ hd ] , 6 peritoneal dialysis [ pd ] ) .
mean renal survival was 64.7 6.3 months ( median : 52 11 ) .
renal survival rates at 1 , 2 and 5 years were 81.7% , 67.3% and 46.1% , respectively [ table 2 ] . patients who needed dialysis were significantly older , had higher serum urea , creatinine , phosphorus , intact parathormone , proteinuria and lower estimated glomerular filtration rate ( egfr ) , serum albumin , hemoglobin levels at presentation [ table 3 ] .
a multivariate logistic regression analysis showed that age , serum creatinine and albumin levels were predictors of esrd [ table 4 ] .
etiology was not a significant predictor of requirement for dialysis . during the first 3 months
follow - up period 26 patients ( 21.4% ) were started on dialysis and14 patients died ( nine patients were receiving dialysis ) .
renal and patient survivals were not significantly different between fmf and tuberculosis groups , except for the first 3 months where patients with tuberculosis significantly more frequently required dialysis ( 8% vs. 23% , p = 0.004 ) ; and had a higher mortality rate ( 2.2% vs. 16.6% , p = 0.018 ) .
renal survival time according to etiology and stage of renal failure demographic features and laboratory findings of the patients according to dialysis requirement multivariate logistic regression analysis of the factors that predicts esrd
survival rates at 1 , 2 and 5 years were 80.7% , 68.2% and 51.3% , respectively [ table 5 ] .
older age , male gender , lower body mass index , egfr , serum albumin and ca levels , shorter time to dialysis , and higher levels of serum phosphorus , intact parathyroid hormone ( ipth ) , ferritin and protein uria were associated with lower odds of patient survival [ table 6 ] .
a multivariate logistic regression analysis indicated that higher serum creatinine ( for creatinine > 1.3 mg / dl , hazard ratio [ hr ] 1.97 , p = 0.019 ; 95% confidence interval [ ci ] 1.1 - 3.5 ) , lower albumin level ( for albumin < 2.6 g / dl , hr 1.87 , p = 0.028 ; 95% ci 1.06 - 3.30 ) , short time to dialysis , dialysis requirement and stage of renal disease were predictors of death [ table 7 , figures 1 and 2 ] .
analysis of survival characteristics according to age groups revealed a dramatically lower life expectancy of patients older than 60 years [ table 8 ] .
patient survival time according to etiology , dialysis requirement and stage of renal failure demographic features , laboratory findings of died and alive patients multivariate logistic regression analysis of the factors that predicts mortality patient survival according to serum albumin level patient survival according to stage of renal disease patients survival time according to age groups mortality of patients who reached to esrd was significantly higher than those who did not ( p = 0.001 ) .
forty - three ( 43/68 , 63.2% ) of all dialyzed patients died , while only 7 ( 13.2% ) of the 53 patients who did not reach to esrd .
mean survival of patients who required dialysis versus who did not were 61.3 8.5 versus 119.1 7.6 months , respectively .
1 , 2 and 5 years survival rates from the start of dialysis were 44.7% , 40.0% and 22.0% compared to 89.2% , 86.3% and 82.7% for patients who did not need dialysis , respectively [ table 5 ] .
mean survival of patients with fmf and tuberculosis were 105.6 12.1 and 66.2 11.6 months , respectively . 1 , 2 and 5 years survival rates of patients with fmf were 92.9% , 82.9% and 62.2% , as compared to 75.8% , 63.1% and 41.5% for patients with tuberculosis , respectively [ table 5 ] .
overall mortality was not significantly different between patients with fmf and tuberculosis , except for greater mortality rate of tuberculosis patients within the first 3 months of follow - up ( p = 0.018 ) .
of 50 patients who died , 9 ( 18% ) were due to chronic nutritional debility , which led to cachexia , malnutrition and infection , 26 ( 52% ) were due to hypotension that led to complications of hd insufficiency such as uremia , hyperkalemia and hypervolemia , and 15 ( 30% ) were due to unidentified causes .
as a complication of chronic inflammatory diseases , chronic infections and fmf , aa amyloidosis is relatively a rare disease in the western world , whereas it is more common in turkey due to the high prevalence of fmf and tuberculosis . in developed countries ,
rheumatic diseases comprise up to 75% of all causes of secondary amyloidosis ; whereas fmf and tuberculosis were the most common underlying diseases both in our and in another large report from turkey .
this difference is supported by a review of 64 patients with aa amyloidosis from the mayo clinic reporting that chronic rheumatologic disorders were responsible for 65% of cases , while 17% were due to chronic infections .
renal involvement , typically manifested by nephrotic range proteinuria and renal failure , occurs in 80 - 90% of cases with amyloidosis and portends poor prognosis and high morbidity .
long standing inflammation forms the basis of development of aa amyloidosis with a mean duration of latency was found 17 years in a uk series , though only a minority of these patients ends up with amyloidosis .
the reasons of this is not clear , but certain genetic isoforms of severe aplastic anemia ( saa ) were found to increase the risk and severity of secondary amyloidosis .
this field of research will provide practical methods to discriminate between high and low risk patients .
the progressive nature of the disease may be predicted very early by the levels of serum aa protein in serum , where levels well above the reference range were shown be indicative of increased amyloid load and organ dysfunction . as with more conventional methods , gertz and kyle analyzed 64 patients with aa amyloidosis and demonstrated that renal dysfunction ( serum creatinine value of > 2 mg / dl ) at presentation was strongly associated with shorter survival .
other studies also confirmed that serum creatinine concentration is an important predictive factor for survival of patients with aa amyloidosis . in our study , patients with serum creatinine of > 2 mg / dl and albumin < 3.5 mg / dl had shorter both renal and overall survival .
in addition , we also found that older age , male gender , higher levels of phosphorus , ipth , albuminuria and lower levels of serum albumin , calcium , hemoglobin were associated with poor prognosis .
this is supported by the fact that serum creatinine level , stage of renal disease , short time to dialysis , dialysis requirement and low serum albumin were found as predictors of mortality in logistic regression analysis .
reports on survival vary depending on whether they are early or new , with older studies had a median survival ranging from 24 to 31 months .
median survival of patients with creatinine levels of at least 1.69 mg / dl ( 150
however , overall survival in our study was better than older reports ( mean : 88.7 7.8 months ) .
furthermore , mean survival reached to nearly 10 years for patients who did not need dialysis .
amyloidosis was associated with poor patient survival following dialysis and/or renal transplantation , reduced renal allograft survival and a significant incidence of disease recurrence in the allograft .
survival rates on dialysis were slightly lower in our patients when compared to 1 , 2 and 6 years survival rates of 72% , 62% and 44% reported by martinez , 1 and 5 year survival rates of 68% and 30% reported by moroni et al .
however , a study by torregrosa showed that 1-year survival rate in dialysis was 42.7% , similar to our results .
another report by estevereveal even worse survival rates at 1 and 2 years , 30% and 5% , respectively . however , in the analysis of studies by moroni and esteve the majority of patients had aa amyloidosis ; they had also patients with primary ( al ) amyloidosis included which could have altered the survival rates
. the differences in survivals could also be due to socioeconomic factors , dialysis practices , extrarenal organ involvement , etc .
furthermore , underlying causes of aa amyloidosis may have an effect on survival , as our study showed that the difference in mortality between patients with fmf and tuberculosis was obvious in favor of fmf , although it did not reach a statistical significance due to a low event rate .
we were not able to assess the effect of normalizing inflammation / high serum saa , but both from a mechanistic standpoint and outcomes of a large series ; one can understand that such an attempt should have a major role in prognosis .
none of the patients in our study received renal transplantation as a mean of renal replacement therapy .
although experience with renal transplantation is limited , studies suggest that patient and graft survivals are similar in amyloidosis and matched control groups with other disorders . in addition ,
posttransplant recurrence of amyloidosis was also low ( 1 in 23 patients ) with colchicine treatment .
these findings should encourage clinicians to provide appropriate candidates with cadaveric or living donor transplantation , as morbidity and mortality with dialysis appear to be worse .
similar to the features of our 31 patients with early mortality , joss et al .
reported that patients who commenced renal replacement therapy or died within 3 months of presentation were significantly older , suffered from more advanced renal disease , had more severe albuminuria and lower serum albumin levels .
in addition , we also found that these patients had higher phosphorus and ipth , and lower calcium and hemoglobin levels .
most common causes of mortality were renal failure ( 35% ) and infections ( 8.5 - 46.6% ) in previous series .
either hd or pd can be used effectively for the treatment of esrd due to amyloidosis , with the limiting factors being the degree of extra renal amyloid deposition , hypotension with hd , and peritonitis with continuous ambulatory peritoneal dialysis . in the present study ,
familial mediterranean fever and tuberculosis are the most frequent underlying causes of aa amyloidosis . aa amyloidosis with renal involvement is progressive and carries a high risk of morbidity and mortality , particularly in those who had massive proteinuria , severe hypoalbuminemia and dialysis requirement at the outset .
we suggest that careful evaluation of manifestations of amyloidosis may give the possibility of making earlier diagnosis , thereby prognosis could be improved .
ea : data collection , literature review , design of the study , patient follow - up .
ek : design of the study , literature review , statistical analysis , patient follow-up.ts : design of the study , literature review , review of manuscript , patient follow-up.tb : patient follow - up , review of manuscript .
Output:
| background : amyloid a ( aa ) amyloidosis is a multisystem , progressive and fatal disease .
renal involvement occurs early in the course of aa .
we aimed to investigate the etiology , clinical and laboratory features , and outcome of patients with biopsy - proven renal aa amyloidosis.materials and methods : a total of 121 patients ( male / female : 84/37 , mean age 42.6 14.4 years ) were analyzed retrospectively between january of 2001 and may of 2013 .
demographic , clinical and laboratory features and outcomes data were obtained from follow - up charts.results:familial mediterranean fever ( 37.2% ) and tuberculosis ( 24.8% ) were the most frequent causes of amyloidosis .
mean serum creatinine and proteinuria at diagnosis were 2.3 2.1 mg / dl and 6.7 5.3 g / day , respectively .
sixty - eight ( 56.2% ) patients were started dialysis treatment during the follow - up period .
mean duration of renal survival was 64.7 6.3 months .
age , serum creatinine and albumin levels were found as predictors of end - stage renal disease .
fifty patients ( % 41.3 ) died during the follow - up period .
the mean survival of patients was 88.7 7.8 months ( median : 63 13.9 ) . 1 , 2 and 5 years survival rates of patients were 80.7% , 68.2% and 51.3% , respectively .
older age , male gender , lower levels of body mass index , estimated glomerular filtration rate , serum albumin , calcium , and higher levels of phosphor , intact parathyroid hormone and proteinuria were associated with a higher mortality .
higher serum creatinine , lower albumin , dialysis requirement and short time to dialysis were predictors of mortality.conclusion:the outcome of patients with aa amyloidosis and renal involvement is poor , particularly in those who had massive proteinuria , severe hypoalbuminemia and dialysis requirement at the outset . |
PubmedSumm118790 | ***TASK***
the task is to summarize an input biomedical literature in six sentences
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the input is a biomedical literature
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the output is the summary of an input biomedical literature in six sentences
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Input: sex differences in brain structure and behavior are ubiquitous in many species , including humans and rodents [ 13 ] .
the gonadal steroid hormones , testosterone ( t ) and estradiol , are essential for these differences [ 46 ] .
there is a strong link between the sex steroids and gender differences not only in normal physiological functions , but also in the prevalence , symptoms , and associated features of many neurological diseases and mental illnesses [ 710 ] .
for example , the greater the t levels in the amniotic fluid during pregnancy , the higher the child 's score on tests of autistic traits .
in addition autism is four times more likely to occur in boys than in girls .
therefore , elucidation of the mechanisms underlying the effects of sex steroids on brain sexual differentiation may help identify the essential processes that mediate gender - specific susceptibility to different diseases and assist in the development of new treatments for these sex - biased disorders . in male mice , the developing testes secrete t with two surges during late gestation ( embryonic days 16 and 17 , e16 and e17 ) and on the day of birth ( postnatal day 0 , pn0 ) , respectively [ 1315 ]
. the perinatal rises in t masculinize and/or defeminize the neural circuits underlying sex - specific behaviors [ 13 , 1517 ] . besides reproductive behavior , androgens are important for sex differences in cognitive and social behaviors that are regulated by the cortex and hippocampus [ 46 , 18 ] . in association with distinct behavioral phenotypes between the sexes , there are structural differences in male and female cortex and hippocampus . in adult mice ,
these differences are associated with the gonadal hormone milieu , especially perinatal t exposure , rather than with the sex chromosome complement .
t exerts its effect on brain sexual differentiation by directly binding to androgen receptor ( ar ) or , after aromatization to estradiol , via estrogen receptors [ 2123 ] .
the critical role of t and ar in masculinization of sexually dimorphic brain regions and various behaviors , including cognitive processing , sexual behavior , and response to stress , is supported by previous studies conducted in rodent models lacking functional ar [ 6 , 24 , 25 ] .
analysis of ar expression in the developing and adult rodent brain reveals sexual dimorphism in the bed nucleus of the stria terminalis ( bnst ) and medial preoptic area ( mpoa ) with higher ar mrna and protein levels in males than females [ 2628 ] . in mice and rats , sex differences in ar expression develop in these brain regions during early postnatal development ( between pn 4 and 10 ) [ 28 , 29 ] .
the bnst belongs to the limbic system and has reciprocal connections with the mpoa , and these two brain regions are part of the neural circuitry that controls male sexual behavior in the adult animals .
sexually dimorphic expression of ar in the bnst and mpoa has been implicated to mediate the actions of androgens in the developing brain in between the sexes .
we have previously observed sex differences in histone modifications in the developing mouse cortex / hippocampus with more h3 acetylation on k9/14 ( h3k9/14ac ) in males around e18 and pn0 and more h3 trimethylation on k9 ( h3k9me3 ) in males around pn0 and pn6 .
sex differences in h3k9/14ac were observed to be regulated by t as a significant increase in h3k9/14ac but not h3k9me3 was found in prenatally t - treated female neonates . since ar interacts with histone modifying enzymes and transcriptional regulation of brain - specific genes by histone modifications has been demonstrated to associate with changes in neural function and behaviors in mice and rats [ 3234 ] , our finding suggests that t might act on ar to alter gene expression in the mouse brain around the time of birth .
based on the importance of t in brain sexual differentiation , we hypothesized that , during early development , ar expression in the mouse cortex / hippocampus might be sexually dimorphic and therefore responsible for the development and function of neural circuits governing distinct behaviors between the sexes . to test our hypothesis , we determined ar mrna and protein levels by rt - qpcr and immunblotting , respectively .
our results reveal the presence of ar mrna and two ar protein isoforms ( 110 kda and 70 kda ) in the male and female mouse cortex / hippocampus during early postnatal development . while males have higher ar protein expression than females on pn7 only , the developing mouse cortex / hippocampus showed a robust increase in ar mrna and protein levels as function of age .
the developmental profile of ar expression in the mouse cortex / hippocampus not only implicates ar in the organization and function of neural circuits for higher cognitive function , such as learning and memory , but also supports ar as a direct target through which different levels of circulating androgens can differentially regulate cortical and hippocampal development and function between the sexes .
adult male and female c57bl/6j ( 000664 ) mice were purchased from the jackson laboratory ( bar harbor , me ) and housed in the california state university long beach ( csulb ) animal care facility .
animals were kept on a 12 : 12 h light : dark cycle ( lights on at 0600 h ) .
food ( teklad mouse / rat diet # 7012 ; harlan laboratories , inc . ,
all experimental procedures were approved by csulb institutional animal care and use committee ( iacuc ) and performed according to association for assessment and accreditation of laboratory animal care international ( aaalac ) guidelines .
adult female mice were individually paired with a fertile male to produce the pups used in this study .
male and female pups were sacrificed by rapid decapitation on the day of birth ( pn0 ) and 7 ( pn7 ) , 14 ( pn14 ) , and 21 ( pn21 ) days after birth .
these ages were chosen to overlap with the sensitive period for brain masculinization ( critical period ) , during which endogenous or exogenous sex steroids have been shown to be effective at inducing male - like brain structure and function as adult ( organizational effect ) .
the brains were immediately removed from the skulls and coronally blocked rostral to the optic chiasm and caudal to the mammillary body .
the top ( dorsal ) half of the brain block , including the cerebral cortex and hippocampus , was dissected out , frozen on dry ice , and then stored at 80c until processing for rna or protein extraction as described previously . besides the presence ( males ) or absence ( female ) of pigmentation in their anogenital regions , the gonads and reproductive tracts of all pups were examined to confirm their sexes . using rneasy lipid tissue kits ( qiagen inc . ,
valencia , ca ) , total rna was extracted from the mouse cortex / hippocampus block according to the manufacturer 's protocol .
individual samples were diluted ( 1 : 50 ) in 10 mm tris ( ph = 7.5 ) ( sigma - aldrich , st .
absorbance at 260 nm ( a260 ) , 280 nm ( a280 ) , and 320 nm ( a320 ) was detected by a bio - rad smartspec plus spectrophotometer ( hercules , ca ) .
rna concentration was calculated at a260 , and purity was determined by the a260/a280 ratio ( between 1.9 and 2.1 ) .
the cdna samples were synthesized from 1 g extracted rna in 20-l reactions using the bio - rad iscript cdna synthesis kit .
the reverse transcription was performed at 25c for 5 min , 42c for 30 min , and 85c for 5 min in a bio - rad mycycler thermocycler .
the pcr primers for ar were the same as those described by bonthuis et al . .
the ar primers were checked for sequence specificity using ncbi 's primer - blast program ( http://www.ncbi.nlm.nih.gov/tools/primer-blast/ ) against refseq rna .
the forward and reverse primers match the sequences of exons 7 and 8 of the mouse ar gene , respectively .
in addition , the primers for two house - keeping genes , actb and rpl13a , were also used as described in our previous study .
all primers were purchased from eurofins mwg operon ( huntsville , al ) and tested in rt - pcr assays for 40 cycles using gotaq hot start green master mix ( promega , madison , wi ) according to the manufacturers ' protocol .
initial tests used an annealing temperature of 2c below the lower melting temperatures of the primers as indicated by eurofins mwg operon .
pcr products were separated and visualized on a 1.5% agarose gel with ethidium bromide and then visualized by molecular imager gel doc xr system ( bio - rad ) .
all primers used in this study produce single pcr products with the correct size in the positive control as calculated and no product in the negative control .
next , diluted cdna stocks were prepared with 8 serial dilutions ranging from 1 : 8 to 1 : 1,024 . for each qpcr reaction , 4 l of cdna , 1 l of each of forward and reverse primers ( 840 nm ) , and 6 l of absolute qpcr sybr green mix ( waltham , ma ) were mixed and amplified on an agilent stratagene mx3000p qpcr system with mxpro qpcr software ( santa clara , ca ) with an initial 15 min denaturation / polymerase - activation at 95c , 40 cycles of 15 s at 95c , 1 min at the optimized annealing temperature , and 30 s at 72c and a dissociation step with 1 min at 95c , 30 s at 60c , and 30 s at 95c .
cycles of threshold ( ct ) were analyzed by linear regression with log base 2 of the dilution as the predictor and ct of the reaction as the response .
all of these primers were suitable for quantification with ( 1 ) the r2 of the regression of at least 0.98 , ( 2 ) ct values at the dilutions of 1 : 4 ( ar and actb ) and 1 : 16 ( rpl13a ) below 30 , and ( 3 ) the dissociation curve with single peaks .
the sequences , annealing temperatures used , and sizes of the resulting pcr products were listed in table 1 .
rt - qpcr reactions for gene expression quantification were run under the same conditions as described above , with 4 l of diluted cdna ( 1 : 4 for ar and actb and 1 : 16 for rpl13a ) .
two replicate reactions for each sample were run , and their ct values averaged before further analysis . for a given sample , unnormalized relative expression values for ar expression
were calculated using pfaffl 's method against the pn0 female baseline , and the female baseline was established by averaging the ct values of all pn0 females .
unnormalized relative ar expression values were divided by the geometric mean of the relative expression values of the two reference genes , rpl13a and actb , to yield normalized relative expression values .
values more than two standard deviations from their group mean were trimmed to two standard deviations from the group mean in the same direction as described previously .
in addition , relative xist mrna levels were similarly measured to further confirm the sexes of the pups used .
mouse brain tissues , including the cortex and hippocampus , were homogenized in cold modified t - per buffer ( pierce biotechnology , rockford , il ) with protease inhibitor cocktail ( sigma - aldrich ) and pmsf ( 1 mm ; sigma - aldrich ) .
brain tissues were homogenized by drawing and ejecting 1520 times through sterile 20 g needles , followed by centrifugation at 10,000 g for 5 min at 4c . the supernatant was separated and stored at 80c .
the lysate protein concentrations of individual samples were determined by bicinchoninic acid ( bca ) assays ( pierce biotechnology ) before electrophoresis .
since the protein samples from eight groups of mice ( n = 6 - 7 per group ) could not be run together on the same gel , immunoblotting was conducted by comparing two different sexes ( females versus males ) at each age ( pn0 , pn7 , pn14 , or pn21 ) or two different ages ( pn0 versus pn21 ) of the same sex ( males or females ) .
protein samples of 20 g each were first separated on 8% sodium dodecyl sulfate polyacrylamide gel electrophoresis ( sds - page ) gels or any kd mini - protean tgx precast gels ( bio - rad ) and then transferred to nitrocellulose membranes using the biorad trans - blot turbo transfer system .
each membrane was rinsed then blocked in tris - buffered saline with 0.1% tween 20 ( tbst ) containing 10% milk at 4c overnight . after blocking ,
blots were rinsed with tbst and then incubated with the primary antibody against ar ( 1 : 5,000 ; n-20 ; santa cruz biotechnology , inc . ,
after rinsing , blots were incubated for 1 h in a horseradish peroxidase- ( hrp- ) conjugated , anti - rabbit igg secondary antibody ( 1 : 10,000 ; sigma - aldrich ) , followed by detection of ar protein bands with supersignal west pico chemiluminescent substrate ( pierce biotechnology ) using the proteinsimple fluorchem e system ( santa clara , ca ) .
the blots were reprobed with the antibody against -actin ( 1 : 200,000 ; sigma - aldrich ) with the anti - mouse igg secondary antibody ( sigma - aldrich )
. the intensities of ar and -actin on individual membranes were measured by densitometry and analyzed with alphaview ( proteinsimple ) . to calculate relative ar protein levels of individual samples , the densities of ar were first normalized with the densities of -actin , and the ratios of ar and -actin levels in individual samples were then standardized to the mean level of females at the same developmental stage ( sex effect ) or the mean level of the pn0 group of the same sex ( age effect ) .
each sample was expressed as the fold - difference from either the female or pn0 value , which were both set at 1-fold .
the body weight , tissue weight , and rt - qpcr data from individual groups were first tested for normality of the residuals by the anderson - darling test and next tested for equality of variances using levene 's test .
if significant deviations were detected ( p < 0.05 ) , a log transformation was applied to the data . after showing normality and homogeneity of variances ,
the data were analyzed by two - way anova to evaluate the effects of sex , age , and their interaction .
when two - way anova showed significant differences , tukey 's post hoc test was used to determine which groups were significantly different .
relative ar protein data were analyzed using student 's t - tests with either sex or age as the single factor .
the ratios of the smaller ar isoform ( 70 kda ) to the full - length ( 110 kda ) were similarly analyzed with two - way anova to reveal the effects of sex and age and their interactions .
the numbers of mice at different ages and sexes used in the current study and their body weights and cortex / hippocampus weights are listed in table 2 .
no significant sex difference in mean body weight ( p = 0.506 ) or tissue weight ( p = 0.55 ) was observed ( table 2 ) .
in contrast , there was a significant effect of age on body weight and brain tissue weight ( p < 0.001 ) , the minimum occurring on pn0 and the maximum on pn21 .
interestingly , while the body weights of these animals continued to increase as age advanced , the maximum brain tissue weight was attained by pn14 .
we used rt - qpcr to determine relative mrna levels of ar in the mouse cortex / hippocampus on pn0 , pn7 , pn14 , and pn21 .
a two - way anova revealed a significant effect of age ( p < 0.001 ) but not sex ( p = 0.058 ) or their interaction ( p = 0.567 ) on ar mrna expression .
using tukey 's post hoc test , we further demonstrated that ar mrna levels in the cortex / hippocampus were significantly higher on pn7 ( 8.29 0.77 , n = 17 ) than pn0 ( 1.06 0.05 , n = 36 ) and continued to rise on pn14 ( 29.89 1.29 , n = 16 ) and pn21 ( 59.10 1.36 , n = 16 ) ( figure 1(a ) ) . although the sex difference did not reach statistical significance ( p = 0.058 ) , there was a trend toward a female bias in ar expression in the mouse cortex / hippocampus , especially on pn14 ( females , 32.45 1.88 , n = 8 versus males , 27.33 1.32 , n = 8) .
in addition , relative xist mrna levels were measured in these animals , and this x - linked gene was exclusively expressed in all female pups , not males , regardless of age ( figure 1(b ) ) . immunoblotting with the antibody against the aminoterminal of ar protein was used to detect ar proteins in the adult mouse brain . as shown in figure 2 ,
two ar protein bands were observed in the adult mouse cortex / hippocampus and hypothalamus , the full - length ar with a molecular weight of 110 kda and a smaller isoform of approximately 70 kda . in the representative blot ,
the mouse hypothalamus showed a male - biased expression of ar proteins ( full - length : female , 1.00 versus male , 2.69-fold ; smaller isoform : female , 1.00 versus male , 3.10-fold ) .
in contrast , in the cortex / hippocampus , the ar protein levels were similar between the sexes ( full - length : female , 1.00 versus male , 1.04-fold ; smaller isoform : female , 1.00 versus male , 0.86-fold ) .
we first tested if ar protein expression in the developing mouse cortex / hippocampus was different between the sexes at the protein level . because all samples could not be run on the same gel , we performed immunoblotting with same - age male and female samples on a single blot to test the effect of sex on ar protein expression .
relative ar levels of individual samples were calculated by normalizing to the mean ratio of ar versus -actin of females in the same developmental stage .
a t - test was conducted to evaluate the effect of sex on ar protein expression in the mouse cortex / hippocampus at pn0 , pn7 , pn14 , and pn21 . as shown in figure 3(b ) , on pn0 , full - length ar protein levels in males ( 0.66 0.10 , n = 7 ) were 66% of those in female controls ( 1.01 0.15 ,
n = 6 ) ( p = 0.084 ) ; however , this trend was reversed on pn7 when ar protein levels were 1.3 times greater in males ( 1.39 0.06 ,
n = 6 ) than in females ( 1.00 0.08 , n = 6 ) ( p = 0.004 ) .
unlike the full - length ar , there was no sex difference in levels of the smaller ar isoform at any time ( pn0 , p = 0.407 ; pn7 , p = 0.603 ; pn14 , p = 0.670 ; and pn21 , p = 0.758 ) ( table 3 ) .
since ar mrna expression increased with age , we next measured ar protein levels in the mouse cortex / hippocampus collected on pn0 and pn21 to determine if there was an age - dependent increase in ar proteins .
all pn0 and pn21 male or female samples were run on single blots ( figure 4(a ) ) , and the relative ar levels in individual samples were normalized to the mean level of pn0 mice of the same sex .
regardless of sex , expression of the 110-kda ar protein in the cortex / hippocampus was higher on pn21 than pn0 in both males ( pn0 , 1.00 0.04 , n = 6 versus pn21 , 8.45 0.74 , n = 7 ) ( p < 0.001 ) and females ( pn0 , 1.00 0.04 , n = 6 versus pn21 , 5.88 0.34 , n = 7 ) ( p < 0.001 ) ( figure 4(b ) , left panels ) . similarly , relative protein levels of the 70-kda ar isoform also increased as age advanced in both males and females ( p < 0.001 ) ( figure 4(b ) , right panels ) .
we found no sex difference in the ratios of the smaller ar isoform to the full - length ar , but there was an age - dependent increase in the ratios : 32.0 2.9% ( pn0 ) , 44.9 4.3% ( pn7 ) , 64.7 1.8% ( pn14 ) , and 59.5 3.1% ( pn21 ) ( p < 0.001 ) ( figure 5 ) .
our study reveals that , as age advanced , levels of ar mrna and two protein isoforms , 110 kda ( full - length ) and 70 kda , increase in the male and female mouse cortex / hippocampus during the first three weeks after birth ( figures 1(a ) and 4 ) . to our knowledge , this investigation represents the first report of identification of a smaller ar isoform in the developing mouse brain .
in addition , we have observed a novel timeline when sexually dimorphic ar expression at the protein , not mrna , level occurs in the developing mouse cortex / hippocampus , with males showing about 39% more full - length ar than females on pn7 ( figure 3(b ) ) .
the sex - specific development of rodent cerebral cortex and hippocampus are sensitive to sex steroids .
for example , adult male mice possess a thicker cerebral cortex than females , which depends on gonadal hormones , rather than the complement of sex chromosomes .
similar to the cortex , the hippocampus of male rats has larger ca3 pyramidal cell field volumes and soma sizes than females , which can be reversed by prenatal treatment of male rats with antiandrogen flutamide or females with testosterone propionate ( tp ) and dihydrotestosterone ( dht ) .
the presence of ar in the developing mouse cerebral cortex and hippocampus may serve as an important mechanism through which androgens can directly regulate the development of dimorphic structures in these two brain regions underlying behavioral and functional differences between the sexes .
given sexual dimorphism in ar protein expression in the mouse brain , the explanation could be as simple as regulation in ar protein synthesis ( translation ) and/or stability ( degradation ) between the sexes via ligand - receptor interaction . while gonadectomy causes a loss of ar protein , androgen supplement after castration restores ar levels in the adult mouse brain and rat prostate [ 27 , 43 ] . in vitro studies
have further demonstrated that the ligand - receptor interaction stabilizes ar protein from degradation and possibly increases its synthesis to upregulate ar expression [ 4447 ] .
thus , the perinatal rise in circulating t released by the developing testes may exploit similar molecular and cellular mechanisms to increase ar protein levels in the male cortex / hippocampus on pn7 ( figure 3(b ) ) .
in addition , masculine elevation of cortical and hippocampal ar protein might be simply caused by increasing the number of ar - expressing cells located in these brain regions via neurogenesis , migration , and differentiation . in good agreement with masculine expression of cortical and hippocampal ar protein shown in figure 3(b ) , nuez et al .
found greater ar - immunoreactive cell density in the primary visual cortex of male rats than females on pn10 , not at younger ages , and further demonstrated that such a sex difference in ar expression was laminar - specific ( limited to layers ii
the latter suggests that more cortical neurons are likely to migrate into the superficial layers of the male cortex , where they differentiate and express ar .
we speculate that , similar to the rat visual cortex , increasing the number of ar - expressing cells via migration might be responsible for the elevated masculine levels of cortical / hippocampal ar protein in pn7 mice ( figure 3(b ) ) .
consistent with their immunocytochemical data , nuez and colleagues also reported higher ar mrna levels detected in the male visual cortex than in females by in situ hybridization whereas we found no sex difference in ar mrna in the developing mouse cortex / hippocampus ( figure 1(a ) ) . besides differences in species ( rat versus mouse ) and quantification techniques ( i.e. , in situ hybridization versus rt - qpcr ) , these discrepancies may be due to the heterogeneity of the cortical and hippocampal neurons , which may mask small variations in ar mrna levels occurring in subpopulations of cells when they are mixed with the rest of the cortex and hippocampus .
other than the cortex and hippocampus , sexual dimorphism in ar expression has also been noted in the rodent bnst and mpoa , which appears near the first postnatal week and then persists throughout adulthood [ 2629 ] . during late gestation and on the day of birth
, there is a transient rise in circulating t in male mice , which is critical for masculine development of ar expression in these two brain regions .
juntti et al . found that treatment of neonatal female pups with tp increased the number of ar - positive cells in their bnst and mpoa on pn6 .
similar to mice , neonatal gonadectomy lowered levels of ar mrna in these two brain regions of pn10 male rats , and replacement of tp to gonadectomized animals maintained their ar mrna content at levels equal to those in intact males .
it has been further demonstrated that estrogenic metabolites aromatized from testosterone may act via ers to regulate sex differences in ar expression in the bnst and mpoa .
this conclusion is based on the findings that estradiol benzoate ( eb ) masculinizes ar expression in females while demasculinization of ar expression is found in males lacking functional aromatase . since there is robust er expression in the developing mouse cortex during first week after birth , the perinatal rise in t
might be converted into estradiol locally to activate er to similarly drive increased ar protein expression in the male mouse cortex and hippocampus during early postnatal development .
unlike the bnst and mpoa , sexually dimorphic ar protein expression in the developing mouse cortex / hippocampus disappears by pn14 ( figure 3(b ) ) .
while two studies reported higher ar mrna expressed in the cortex of male mice than in females [ 50 , 51 ] , thakur et al . and
our data shown in figure 2 show that the full - length ar protein levels seem to remain sexually indifferent in the adult mouse cortex and hippocampus .
these results indicate that ar transcription and translation as well as posttranscriptional and posttranslational modifications in the developing cortex and hippocampus might be regulated differently as compared to the bnst and mpoa .
in addition , several unique features render ar cells in the cortex distinctly different those in the hypothalamus .
first , in comparison to ar - immunoreactive cells in the hypothalamus , the intensity of ar label per cell in the cerebral cortex is moderate .
second , the total population of ar - positive cells is greater in the telencephalon , including the cortex and hippocampus , than in the diencephalon .
third , immunoreactivity for intracellular ar is abundant within the layers ii / iii and v / vi of the sensory and motor cortex , in which the majority of ar - positive cells are pyramidal neurons .
fourth , ars in the cerebral cortex are located not only in the nucleus but also in the axons and dendrites while ar expression in the hypothalamic regions is exclusively nuclear .
although sexual dimorphism in ar expression in the mouse cortex / hippocampus does not persist beyond pn7 or into adulthood , differences in circulating androgens between the sexes can still modulate ar function in a sex - dependent manner . in mice ,
ar transcripts can be detected in the neuroepithelium of brain vesicles as early as e11 and later appear in the cerebral cortex and hippocampus as well as the hypothalamus during e15-e16 .
in contrast to a relatively small , transient difference in ar expression between the sexes on pn7 ( 39% more in males than in females ) , we demonstrate a robust , age - dependent elevation of ar mrna and proteins in the male and female mouse cortex / hippocampus during early postnatal development .
when comparing pn0 and pn21 mice , there are a 59- and an 11-fold increases in mrna and protein levels , respectively ( figures 1(a ) and 4(b ) ) .
the difference in the fold changes between ar mrna and protein in the cortex / hippocampus suggest differential rates of ar transcription and translation as well as degradation of its mrna and protein .
in addition , the differences in detection sensitivity and quantification mechanisms between rt - qpcr and immunoblotting might also be part of the cause .
in addition to differential regulation of transcription , translation , and degradation , developmental changes in cortical and hippocampal ar protein levels in the developing brain might be the result of increased migration , proliferation , and differentiation of ar - expressing cells with age , which is supported by previous studies .
found moderate numbers of ar - immunopositive cells in the ca1 , ca2 , and subiculum at pn0 , and then the numbers of ar - positive cells in these three regions increased at pn15 and reached the maximum by pn45 .
similar to the hippocampus , the rat primary visual cortex and anterior cingulate / frontal cortex both show an increase in ar - immunoreactive cell density with age , lower on pn0 than on pn10 .
additionally , ar cells were observed only in layers v and vi of the neonatal visual cortex .
as age advances , ar immunoreactivity was observed in more superficial layers , layers ii vi , on pn4 , followed by robust increases in the ar cell density in layers ii iv and modest increases in layers v and vi on pn10 .
these findings indicate that the developmental changes in the density and number of ar - immunoreactive cells in the cortex and hippocampus are region - specific , which might result from neuronal migration and differentiation occurring in the specific layers of the cerebral cortex . in the present study
, we observed a smaller ar isoform with a molecular weight of approximately 70 kda coexpressed with the full - length ar ( ~110 kda ) in the developing and adult mouse cortex / hippocampus and hypothalamus ( figures 2 , 3(a ) , and 4(a ) ) . both ar
proteins are recognized by the same antibody raised against a peptide mapping at the aminoterminus of human ar , suggesting that the smaller ar might be composed of at least part of the aminoterminal sequence of the full - length ar . a variety of smaller ar isoforms
have been previously identified and characterized in prostate cancer cells . like the mouse cortex / hippocampus , 22rv1 cells , a human prostate carcinoma epithelial cell line ,
are also found to express two ar protein species of ~112 and 7580 kda .
first , it can be produced via proteolytic degradation of full - length ar by calpain-2 or caspase-3 .
second , alternative splicing could be another important contributor to the synthesis of truncated ar species lacking the ar ligand binding domain ( lbd ) . using antibody mapping , the smaller ar species
is composed of the ar aminoterminal domain and dna binding domain but lacks the carboxyl - terminal lbd .
further , the truncated ar is nuclear , binds to are , and regulates gene transcription independent of androgens but does not interact with full - length ar .
selective abolition of expression of the full - length ar or both ars by sirna demonstrates that androgen - independent ar target gene expression and cell growth are mediated by the smaller ar species .
although the exact function of the 70-kda ar isoform in the brain is unclear , based on the in vitro data , we speculate that this smaller ar isoform might regulate the transcription of specific genes responsible for cortical and hippocampal function via interfering with t - dependent and t - independent pathways .
in summary , ar mrna and proteins are present in the developing mouse cortex / hippocampus on the day of birth in both males and females , followed by a robust increase in ar expression at the mrna and protein levels with age during the early postnatal period .
this developmental profile of ar expression indicates that age - dependent regulation of ar transcription , splicing , and/or translation might be involved in programming the structure of the cortex and hippocampus , ultimately contributing to the control of social and cognitive behaviors as well as the underlying neural circuits .
although the sexually differentiated expression of full - length ar protein in the developing mouse cortex / hippocampus is transient , whenever ar protein expression is similar between the sexes , the differences in circulating androgens could still play an important role in modulating ar function in a sex - dependent fashion .
future studies will focus on investigating ar expression specifically in discrete subregions of the cortex and hippocampus .
Output:
| during the perinatal period , male mice are exposed to higher levels of testosterone ( t ) than females , which promotes sexual dimorphism in their brain structures and behaviors .
in addition to acting via estrogen receptors after being locally converted into estradiol by aromatase , t also acts directly through androgen receptor ( ar ) in the brain .
therefore , we hypothesized that ar expression in the developing mouse cortex and hippocampus was sexually dimorphic . to test our hypothesis , we measured and determined ar mrna and protein levels in mouse cortex / hippocampus collected on the day of birth ( pn0 ) and 7 ( pn7 ) , 14 ( pn14 ) , and 21 ( pn21 ) days after birth .
we demonstrated that , as age advanced , ar mrna levels increased in the cortex / hippocampus of both sexes but showed no sex difference .
two ar proteins , the full - length ( 110 kda ) and a smaller isoform ( 70 kda ) , were detected in the developing mouse cortex / hippocampus with an age - dependent increase in protein levels of both ar isoforms at pn21 and a transient masculine increase in expression of the full - length ar protein on pn7 .
thus , we conclude that the postnatal age and sex differences in ar protein expression in combination with the sex differences in circulating t may cause sexual differentiation of the mouse cortex / hippocampus . |
PubmedSumm118791 | ***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: urolithiasis is one of the most common urological diseases with various surgical treatments available for its management .
one of most utilized surgical modalities is ureteroscopy ( urs ) with endoscopic stone lithotripsy .
urs , either rigid or flexible , is the treatment of choice for almost all ureteral stones and for certain cases of intrarenal lithiasis .
although its therapeutic benefits are recognized , urs is associated with complications that range from pain and hematuria to ureteral perforation , ureteral avulsion , fever , sepsis , and death . with regard to the infectious complications of urs lithotripsy ,
there are certain serum markers including pro - inflammatory cytokines that are gaining importance in clinical practice [ 35 ] .
cytokines are a group of peptides that regulate the humoral and cellular components of the immune system and in vivo inflammatory responses .
interleukin-6 ( il-6 ) is an inducer of activation and differentiation of b and t cells during inflammatory responses . il-6
tumor necrosis factor- ( tnf- ) is produced by many cells in vivo . increased and
prolonged release of tnf- is harmful and causes inflammation and tissue damage . in the present study
, we used serum levels of il-6 and tnf- as markers of inflammation in order to investigate the potential association between these markers and the infectious complications of urs lithotripsy .
thirty patients ( 19 males , 11 females ) , mean age of 47 ( range : 2668 ) with ureteral lithiasis treated with ureteroscopic lithotripsy , and 10 healthy volunteers serving as the control group were studied .
none of the patients treated with urs had received previous treatment for stones ( urs , pcnl , or esw ) and none had a history of systemic or immunosuppressive disease . other exclusion criteria included age less than 18 or more than 80 , previous insertion of a ureteral stent or nephrostomy tube , neoplasmatic disease , and renal insufficiency .
urine cultures , before and after urs , were routinely obtained in all patients in order to exclude the presence of urinary tract infection .
all urs cases were performed at the dedicated stone center of the university hospital of alexandroupolis .
a 8.5 f semirigid ureteroscope ( olympus medical systems europa gmbh ) was used and lithotripsy was performed using a holmium laser lithotripter ( dornier medilas med tech emea ) .
standard rigid forceps or disposable baskets ( cook medical , bloomington , in , usa ) were selectively used for retrieval of stone fragments .
a double - j catheter was usually left after the surgical intervention depending on the surgeon 's discretion .
serum levels of both tnf- and il-6 were measured in all patients before the procedure ( previous day ) and at certain time points following the urs .
tnf- was measured at 1 hour postoperatively and again at 24 and 48 hours postoperatively , while il-6 levels were measured at 2 hours postoperatively and again 24 and 48 hours after the case .
the samples were centrifuged at 4000 rpm for 10 minutes at 4. the serum samples were divided into aliquots and stored at 85c for the assessment performed in weekly intervals .
serum interleukin-6 concentrations were measured using the commercial biosource europe sa il-6- irma and tnf-- irma ( rue de l'industrie 8 b-1400 nivelles , belgium ) kit ( code 30 126 00 for il-6 and
the reference range for il-6 normal values was 631 pg / ml for healthy controls and for tnf- 5 pg / ml , respectively .
statistical analyses of serum tnf- and il-6 values of control group and 1 ( or 2 for il-6 ) , 24 , and 48 hours after urs were performed using bivariate linear correlation model between the groups of interest ( pearson 's test ) .
the dependence of serum tnf- and il-6 values with the other variables ( blood sample collections after urs ) was assessed using paired samples t - test with confidence interval 95% .
we found significant differences between the cytokine levels in the serum samples taken before and two hours after urs ( independent variable the control group ) ( table 2 ) .
some changes in serum cytokine levels were observed in bivariate linear correlation between the groups of interest ( pearson 's test ) and are shown in table 3 .
serum tnf- levels were significantly increased after one hour ( p = 0.0083 ) and 28 hours ( p < 0.001 ) after urs .
il-6 was also significantly increased after 2 and 24 hours of urs ( p < 0.001 ) .
macroscopic hematuria was observed in 4 patients , while in the remaining 26 patients microscopic hematuria was detected .
postoperative fever ( > 38.5c ) was developed in 2 patients ( 6,6% ) and was managed with i.v antibiotics ( ciprofloxacin 1 gr / day for 7 days ) .
both patients had negative urine culture both before and after urs and both had double - j stents inserted at the end of the case . in these two patients the preoperative values for tnf- were 30 pg / ml , 22 pg / ml for tnf- , and 50 and 48 pg / ml for il6 .
postoperatively in one hour for tnf- the serum values increased to 40 , 45 pg / ml and in two hours for il increased to 62 , 59 pg / ml .
urs although highly effective in the treatment of ureteral stones may be associated with certain complications .
complications related to inflammation and infection are those more commonly seen after urs lithotripsy . in an effort to predict the patients that are more prone to inflammatory complications following urs a number of potential markers have been proposed .
activation of local and systemic metabolic response to trauma and systemic inflammatory response syndrome ( sirs ) is mediated mainly by activation of interleukins ( il ) and tumor necrosis factor- ( tnf- ) .
once il and tnf are secreted , they activate several other reactions exacerbating the host inflammatory response . in vitro human blood monocytes produce il and tnf- when they are exposed to 25 to 50 pg / ml of endotoxin concentration .
these endotoxin levels have been reported in the bloodstream of patients during septic shock . in a clinical report of 97 consecutive patients ,
56% developed sepsis with about 26 pg / ml of tnf- 37% had 20 pg / ml of il-1 and in 80% ; 415 pg / ml of il-6 was detected , including a lps mean concentration of 2.6 endotoxin units ( eu)/ml ( 1 eu / ml = 0.6 ng / ml ) . in our study
we observed that patients with a postoperative fever showed a higher preoperative expression of serum tnf- and il6 .
these high levels were maintained and increased in one hour ( for tnf- 40 and 45 pg / ml ) and two hours ( for il 62 and 59 pg / ml ) .
these two patients were treated with intravenous antibiotics and required more days of hospitalization ( 4 additional days ) .
infection and fever were considered as an unpleasant postoperative complication possibly unrelated to the minimally invasive nature of urs .
serum il-6 level is a suitable indicator for clinical purposes , because its peak can be measured even on the day after the operation ( 14 to 20 hours after surgery ) . in the study by igarashi et al .
briefly , open surgery resulted in the most exaggerated increase in serum il-6 levels , followed by laparoscopic surgery , endoscopy , and eswl . on the other hand tnf levels increase within 1 hour and then return to baseline within 3 hours after endotoxin administration .
also the plasma concentration of il-6 showed an increase in 2 to 4 hours following intravenous endotoxin .
il-1 was detected in 60 min and high levels occurred in 3 hours following lipopolysaccharide stimulation of monocytes .
peak levels of il-1b were also observed at 3 hours during experimental endotoxemia . based on this data , in our study
the cytokine levels were measured at the first and second hour for tnf- and il-6 , respectively , after urs .
the significance in the increase of serum tnf- and il-6 levels may be due to the sampling method , which serum once at a specific time .
serum tnf- levels were statistically significant , increased 1 hour ( p = 0.0083 ) and 48 hours ( p < 0.001 ) after operation .
il-6 levels were found statistically significant , elevated after 2 and 24 hours from the urs ( p < 0.001 ) .
furthermore our series revealed that the serum il-6 and tnf- levels differed according to postoperative timing of blood collection .
as indicated in table 2 the mean value for serum il-6 before urs was 24 pg / ml and 41,74 36,87 66,54 for 2 , 24 , and 48 hours after urs and for tnf- the values were 19,90 40,09 17,19 and 26,28 before urs 1 , 24 , and 48 hours postoperatively .
limitations of our study include its small size and also the lack of data on stone composition and culture .
however we were able to show that cytokines could be helpful as markers of inflammation and potential infectious complications following urs with more accuracy than urine culture .
therefore despite the above mentioned limitations , we consider that our results may be helpful in designing future studies that will address the clinical significance of serum markers of inflammation in the management of patients with stones .
high preoperative levels of serum tnf- and il-6 may be indicators of an inflammatory predisposition and could be used as preoperative markers .
further studies that measure the cytokine levels at various intervals before and after urs lithotripsy treatment may help to investigate the possible association between preoperative serum values and postoperatively infectious complications .
Output:
| introduction . ureteroscopic lithotripsy ( urs )
although highly effective for the treatment of ureteral stones is associated with certain complications , the more common of which are postoperative fever and infection . in the present study we aimed to evaluate the levels of serum cytokines in patients undergoing ureteroscopic lithotripsy and investigate any possible correlation between levels of cytokines and infectious complications after urs .
materials and methods .
thirty patients ( 19 males , 11 females ) , with a mean age of 47 ( range : 2668 ) that underwent urs lithotripsy for ureteral stones , and 10 healthy volunteers serving as the control group were enrolled in this study .
serum samples for tnf- and il-6 were obtained before surgical intervention and after 1 , 24 , and 48 hours and 2 , 24 , and 48 hours , respectively .
the preoperative and postoperative levels were compared and correlated with the possible complications after urs .
results .
serum tnf- levels were statistically significant , increased 1 hour ( p = 0.0083 ) and 48 hours ( p < 0.001 ) after operation .
il-6 levels were found statistically significant , elevated after 2 and 24 hours from the urs ( p < 0.001 ) . in 2 patients we observed postoperative fever ( > 38.5c ) .
these two patients had high preoperative values of tnf- and il-6 ( 30 and 50 pg / ml , resp . ) and these values increased postoperatively . conclusion .
high preoperative levels of serum tnf- and il-6 may indicate a predisposition for postoperative inflammation and infection following urs lithotripsy . |
PubmedSumm118792 | ***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 assessment of gelatin authentication and origin is of major concern for standards authorities , not only to assist in the prevention of commercial fraud in the food , cosmetic , and pharmaceutical industries [ 1 , 2 ] , but also to help avoid the safety risks derived from diseases among livestock that might be harmful for human health .
the correct identification of gelatin species thus becomes an issue of primary relevance for these industries .
the characterization of external morphological features is a particularly difficult method for gelatin species differentiation because of their apparent similarities and to the fact that they are frequently lost during the manufacturing process .
an alternative , molecular method for gelatin species identification based on dna or protein analysis is tedious and time consuming .
polymerase chain reaction ( pcr ) method has been used in dna analysis but again is not available for gelatin identification because of the heavy destruction of dna in gelatin during processing , although this method has been widely applied in collagen identification [ 3 , 4 ] .
similarly , the immunochemical method has been used to identify collagen , but again the usefulness of this method might be influenced by the extent of the proline hydroxylation which plays an important role in determining the antigenicity of collagen . as a result of the problems with the methods that we have outlined ,
proteomics methods have been proposed as alternative tools for the assessment of the authenticity and traceability of collagen species in gelatins , and mass spectrometry has been successfully applied to elucidate differences among homological gelatins . in line with these results , we developed an analytical method based on proteomics to distinguish these gelatins effectively .
, we have characterized the specific peptides from five species of gelatins by means of uplc - qtof / ms coupled with pca .
the analysis of tryptic peptides , as commonly used in proteomics , is a powerful technique for the identification of proteins [ 9 , 10 ] .
a complex peptide sample is typically first separated into its constituents by using hplc - dad ( diode array detector ) and hplc / ms / ms [ 11 , 12 ] procedures . in recent years , the new analytical technique of ultraperformance liquid chromatography has been developed for the study of proteins [ 13 , 14 ] .
this method uses small particle size packing in the column to provide better chromatographic resolution .
a peptide resulting from tryptic digestion normally has a basic residue ( arginine or lysine ) at its c - terminus and yields a prominent doubly charged ion peak when ionized by esi .
if this ion is chosen as the parent ion for an ms / ms measurement , the production of a series of y - ion daughters ( ions resulting from cleavage at the amide bonds and containing the c - terminus ) is favored and the resulting spectrum is likely to be easy to interpret .
for this reason we selected the doubly charged ion as the parent ion for our analysis .
the objective of this work is the study of gelatins using the doubly charged selected ion coupled with ms / ms fragments monitoring ( dcsi - ms / ms ) to aid in the identification of gelatins .
the gelatins were digested by trypsin , liquid chromatography separation , and peptide identification by ms using the dcsi - ms / ms scanning mode , as a reliable method for fast and effective gelatin identification .
in addition , the possibility of detecting the target peptides in these samples with rapid resolution liquid chromatography ( rrlc ) separation , using an electrospray ionization- ( esi- ) ion trap ( it ) ms , was tested .
acetonitrile ( hplc grade ) was purchased from merck ( rahway , nj , usa ) .
methanol ( hplc grade ) was purchased from fisher scientific ( pittsburgh , pa , usa ) .
ultra - high - purity water was prepared by a milli - q water purification system ( millipore corporation , bedford , massachusetts ) .
trypsin ( sequencing grade ) was obtained from promega ( madison , wi , usa ) .
a syringe filter ( 0.22 m ) was purchased from millipore ( billerica , ma , usa ) .
five of the 20 samples tested were donkey - hide gelatins , belonging to the family equidae , six samples were bovine - hide gelatins belonging to the family bovidae , three samples were porcine - hide gelatins belonging to the family suidae , three samples were deerhorn gelatins belonging to the family cervidae , and three samples were of tortoise shell glue , belonging to the family emydidae .
first , 100 mg of the gelatin standard was dissolved in 50 ml of a 1% nh4hco3 solution ( ph 8.0 ) .
then , 100 l of the gelatin solution was drawn , and 10 l of trypsin solution ( 1 mg / ml in 1% nh4hco3 , ph 8.0 ) was added .
chromatographic separation was performed on an agilent g6320 series lc / msd trap mass spectrometer system .
the actual chromatographic separation was carried out using an agilent 1200 series rapid resolution lc system ( agilent technologies , usa ) , equipped with a binary pump , a microvacuum degasser , a high performance autosampler , a column compartment , a diode array detector , and a ms detector .
the samples were separated on an agilent zorbax sb - c8 ( 100 mm 2.1 mm , 1.8 m ) . the mobile phase consisted of solvent a ( 0.1% formic acid in water , v / v ) and solvent b ( acetonitrile ) .
the optimized rrlc elution conditions were as follows : 0.025.0 min , 5%20% b ; 25.040.0 min , 2050% b ; 40.041.0 min , 5099% b ; 40.045.0 min , 99% b ; 45.045.1 min , 99.05.0% b ; 45.155.0 min , 5.0% .
the flow rate of the drying gas and the pressure of the nebulizing gas were set at 6 l / min and 60 psi , respectively .
the capillary voltage was kept at 3.5 10 v. full - scan spectra were acquired over a scan range of m / z 502200 .
qualitative analyses were programmed to be carried out by using the doubly charged selected ion monitoring ( dc - sim ) mode of the doubly charged ion peak from previously characterized peptides .
an agilent chemstation was used to control and process the data from the agilent 6320 series ion trap lc - ms .
specificity was performed by using one gelatin as a sample , while the other four gelatins were present as blank samples .
the chromatographic peak was verified by comparing the retention times and the fragments of the peaks , with the retention times and the fragments of the characterized species - specific peptides of every kind of gelatin listed in table 1 .
five same samples were digested in the same condition ; the marker peptides in these five same samples could be detected ; the selected ions chromatograms for the five samples from the family equidae are shown in figure 1 .
the samples were frozen at 20c , thawed at room temperature , and then , when completely thawed , refrozen for 24 hours under the same conditions with at least a 12-hour interval between each cycle .
this freeze - thaw cycle was repeated three times before the analysis of the samples was carried out using the method described above .
long - term stabilities were measured by leaving samples at 20c or at ambient temperature for a certain time period ( 20 days or 24 hours , resp . ) , after digestion .
the results show that the characterized species - specific peptides of samples kept at 20c for 20 days and then thawed at room temperature can still be detected .
the complex peptide pools obtained by tryptic digestion of gelatins were subjected to lc - ms / ms , analyzing only five precursor ions at m / z 765.8 , m / z 641.8 , m / z 924.5 , m / z 758.8 , and m / z 732.8 , which were the doubly charged ions of the previously described species - specific peptides .
once the ms / ms spectra of these precursor ions were recorded , chromatogram traces for the different fragment ions could be obtained .
the fragmented ions produced by precursor ions were determined by the sequence of the marker peptide , so the averaged ms / ms spectra obtained around this retention time gave a perfect agreement with the peptide pattern , even without knowledge of sequence of the marker peptides .
figure 2 shows the selected ion chromatography of five gelatins obtained by dc - smim .
figure 3(a ) is the doubly charged ion m / z 765.8 fragmentation spectra representing the presence of the characteristic species - specific peptide of donkey - hide gelatin .
four spectra proving the presence of the corresponding characteristic species - specific peptides for the remaining gelatins are shown in figures 3(b)3(e ) .
commercial samples were also effectively identified after matching specific peptides in these samples with the corresponding reference samples .
ten of twenty commercial samples were donkey - hide gelatins , five were bovine - hide gelatins , three were deerhorn gelatins , and two were tortoise shell glue .
the results presented in this paper confirm the validity of our previously presented approach , which showed that the characterized species - specific peptides of gelatins can be used to distinguish one gelatin from a second or to identify individual gelatins in a mixture . in our work , five doubly charged ions at m / z 765.8 , m / z 641.3 , m / z 924.5 , m / z 758.8 , and m / z 732.8 , which are the respective species - specific peptides of donkey - hide gelatin , bovine - hide gelatin , pig - hide gelatin , tortoise shell glue , and deer - horn glue , were selected as monitor ions .
our results show that using the method we outline in this paper based on the high separation capability of rrlc and the peptide identification ability of ms using the dcsi - ms / ms scanning mode to detect and monitor diagnostic peptides from five different gelatins is simple , rapid , and exclusive .
Output:
| in electrospray ionization ( esi ) mode , peptides and proteins can be multiply charged ions ; in this situation a doubly charged selected ion ( dcsi ) coupled with mass spectrometry ( ms / ms ) fragments monitoring ( dcsi - ms / ms ) method is the most suitable scanning mode to detect known peptides in complex samples when an ion - trap mass spectrometer is the instrument used for the analysis . in this mode ,
the ms detector is programmed to only select a doubly charged ion as a precursor and to perform continuous ms / ms on one or more of the selected precursors , either during a specific time interval or along the whole chromatographic run .
gelatin is a mixture of high molecular weight polypeptides from the hydrolysis of collagen . in this study ,
the dcsi - ms / ms monitoring mode was applied to the detection of previously characterized species - specific peptides from different gelatins .
the proposed methodology makes use of tryptic digestion for sample preparation and peptide separation and identification by rapid resolution liquid chromatography coupled to an ion trap working in the dcsi - ms / ms mode for the analysis .
this methodology was applied to the differential classification of five commercial , homological species of gelatins and proved to be an excellent tool for gelatin product authentication . |
PubmedSumm118793 | ***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 rising interest in esthetic dentistry by patients over the past decade has led to an increased demand for metal - free restorations in the posterior as well as anterior region25 .
because of their esthetics and biocompatibility , many patients prefer all - ceramic crowns to metal - ceramic crowns . nowadays
, strong ceramic core materials have been developed to support the weaker veneering ceramic materials , particularly for the use of all - ceramic restorations in the posterior region6 .
lithium - disilicate glass - ceramic , glass - infiltrated alumina and tetragonal stabilized zirconia are useful for three - unit bridges in present time15 . in 1998 ,
three - unit bridges made of lithium disilicate glass ceramic were introduced for the replacement of a missing tooth up to the first premolar , where the recommended connector crosssection area is 16 mm2,20,23 . in 2005
, an improved press ceramic material called ips e.max press was introduced to the market .
this pressed ceramic is intended to expand the range of indications of empress 2 . while it features similar physical properties as the latter ,
ips e.max press system encompasses a high - stability framework material which consists of lithium disilicate ( 2 sio - li2o ) .
the restorations can be customized either by using a layering technique based on fluorapatite glass ceramic or by using the staining technique24,26 .
as far as it could be arcertained , there is no study concerning the resistance of implant - supported ips e.max press restorations in the literature .
as they have aided overcoming several of the limitations encountered with prosthetic solutions , dental implants have become a reliable alternative in the treatment of partial or complete edentulism .
studies evaluating the long - term prognosis of implant - supported restorations have been published2,9 .
it is well known that the load bearing capacity of bridges depends on the ceramic material 's properties , but also to a high extent on the size , shape and position of the connectors , as well as on the span of the pontics20 , the fabrication technique , the surface finish of the crowns and the luting method1,3,4 .
pontic designs were well described for situations that require pontics in the fabrication of fixed partial dentures .
these designs are include : saddle ( ridge lap ) , modified ridge lap , hygienic ( sanitary ) , conical and ovate .
pontics of bridges have to fulfill esthetic , mechanical , functional , and hygienic requests in prosthetic dentistry .
proper design is more important for cleanability and good tissue health than the choice of materials22 .
the final healed ridge shape may be an even greater departure from the orginal configuration .
the tooth opposite the gap can begin to drift out of its socket . in these cases
if the pontic design is altered , the characteristic stress pattern can be optimized to improve the survival time of implant - supported all - ceramic bridges .
the purpose of the the study was to evaluate the effect of different frameworks designs ( concave , convex and biconvex pontic design ) on fracture resistance of all - ceramic systems by loading test .
the null hypothesis tested was that the different pontic designs do not affect the fracture resistance of all - ceramic restorations .
to simulate clinical conditions , 2 implants ( iti solid screw implants , 3.8-mm diameter , 10-mm bone sink depth ; straumann ag , waldenburg , switzerland ) were arranged in a stainless steel model .
this distance was approximately corresponded to a three - unit dental bridge from a second lower premolar to a second lower molar .
the cement retention abutments ( solid abutments ; straumann ag ) were tightened to 35 ncm using the implant manufacturer 's torque device ( straumann ag ) .
biconvex form designed as the control group , 1 mm curves to the direction of the occlusal surface ( convex form ) and 1 mm curves to the direction of the gingival surface ( concave form ) .
convex and concave pontics had an occluso - gingival height of 4 mm , and a bucco - lingual width of 4 mm whereas biconcave pontic had an occluso - gingival height of 6 mm , and a bucco - lingual width of 4 mm .
a high viscosity ( zetaplus ; zhermack , rovigo , italy ) and low viscosity hydrocompatible condensation silicone ( oranwash l ; zhermack , rovigo , italy ) were used to fabricate indexes on a wax - up of the first specimens .
this index was used to prepare standardized wax patterns with the same dimensions for the rest of the specimens .
the dimensional accuracy of each of the specimens was controlled with a micrometer ( mitutoyo absolute digimatic ; mitutoyo ltd , hampshire , england ) .
the wax frameworks were sprued and invested with a speed investment material ( ips pressvest speed ; ivoclar vivadent ag , schaan , liechtenstein ) .
a lithium - disilicate glass - ceramic ingot ( ips e.max press ; ivoclar vivadent ag ) was heated and pressed into an investment mold in the furnace ( ep 600 ; ivoclar vivadent ag ) after the burn out of the wax analogue .
after divestment with glass polishing beads at 4 bar pressure , fine divestment was carried out with glass polishing beads at 2 bar pressure .
the pressed frameworks were immersed into the 1% hydrofluoric acid ( invex liquid ; ivoclar vivadent ag ) and clean in an ultrasonic cleaner ( whaledent biosonic jr .
the white reaction layer was removed carefully using aluminium oxide at 2 bars . to standardize the ceramic layer thickness ,
one framework for each group was veneered ( ips e.max ceram dentin a1 , ips e.max ceram transpa incisal , ips e.max ceram glaze paste , ivoclar vivadent ag ) .
three silicone molds were manufactured for each group , allowing all other bridges to be veneered similarly .
one type of porcelain was used for all specimens , and the manufacturer 's instructions were followed .
the protocol applied comprised dentin firing i and ii , and glaze firing with glazing material .
all frameworks were independently evaluated by 2 experienced clinicians using visual and tactile methods to ensure that the fit was acceptable . the shapes of the three - unit restorations are shown in figure 1 .
axial compressive load was applied at central of pontic through steel ball ( 10.5 mm in diameter ) ( figure 2)14,18,29 .
the fracture resistance of bridges was determined at a constant cross - head speed of 0.5 mm / min on a universal testing machine ( tstm 02500 , elista corp . ,
loading was continued to the point of fracture , and values of failure loads ( n ) were recorded with computer software .
the crack initiation point on the load - versus - chart - speed curve for the all - ceramic bridges was determined by a sharp decrease in the loading curve and confirmed by an audible sound .
additionally , the location and nature of the fracture patterns was recorded and photographed by using a ccd camera ( dfk 21af04 , the imaging source europe gmbh , bremen , germany ) and a computer ( toshiba satellite l10 - 102 ; toshiba europe gmbh , hampshire , england ) ( figures 2 and 3 ) .
the fracture resistance values of all specimens were analyzed statistically by kruskal - wallis and mann - whitney u tests .
the groups were compared to verify the differences at a significance level set at p<0.05 using the spss 11 for windows statistical software ( spss inc . , chicago , il , usa ) .
the fracture resistance values of all specimens were analyzed statistically by kruskal - wallis and mann - whitney u tests .
the groups were compared to verify the differences at a significance level set at p<0.05 using the spss 11 for windows statistical software ( spss inc . , chicago , il , usa ) .
the fracture resistance values of bridges designed with biconvex , convex or concave pontics were 349.71 , 438.20 and 300.78 n , respectively . kruskal - wallis test revealed a significant difference ( p= 0.026 ) between mean fracture loads according to type of pontic design ( table 1 ) .
bridges designed with convex pontic showed the best mechanical properties as demonstrated by the high values of fracture resistance .
however , no statistically significant differences ( p>0.05 ) were found between the fracture resistances of the groups , except for convex and concave groups ( p<0.05 ; p=0.009 ) ( table 1 ) .
different letters indicate statistically significant difference at 5% level the fractures were located between the loading point and one of the connectors .
the ways of crack propagation were mostly oblique gingivo - occlusally through the connector and pontic and parallel bucco - lingually to the occlusal surface along the occlusal embrasure ( figure 3 ) .
the fracture location occurred in the mesial or distal regions of the pontic ( table 2 ) .
all - ceramic bridges exhibited outstanding esthetics and excellent biocompatibility have been increasingly used during the past decade and today .
continuous development of both ceramic materials and fabrication techniques in addition to recent advances in bonding materials allowed for the introduction of new all - ceramic systems17,12,13 .
the mechanical properties of these systems have to meet the requirements needed to withstand the stresses and strains that can arise in this region because of the increasing use in posterior regions21 .
many studies on the fracture resistance of all - ceramic fixed partial dentures were investigated the effect of connector area and span of the pontic10,15,18,19,28 .
however , the shape of pontics may also influence the clinical performance of a restoration .
tsumita , et al.30 ( 2005 ) stated that the concave shape caused the highest maximum tensile stress , and high tensile stresses were appeared at the lower surface of pontic .
researchers also reported that convex design reduced the stress contrentration at the connector area of the gingival embrasure , and this pontic shape resisted the load as compressive stress .
kokubo , et al.14 ( 2007 ) evaluated the effect of straight , convex and concave pontic designs on the fracture resistance of implant - supported all - ceramic fixed partial dentures and declared that convex design is particularly useful for molar region .
the results of present study agree with those of tsumita , et al.30 ( 2005 ) and kokubo , et al.14 ( 2007 ) .
it is known that porcelain is weaker when stressed at tension and it is much stronger under compression17 .
tensile stresses tend to occur at lower surface of concave or straight beams by loading16 .
also , the convex arches are the most efficient method of forming a structure with materials that have good compressive strength and low tensile strength16 .
therefore , highest values of fracture resistance with respect to the other pontic designs studied were observed at convex design , while concave design showed lowest values of fracture resistance .
based on these results , the null hypothesis that different pontic designs would not affect the fracture resistance of all - ceramic restorations was rejected .
it has been reported that the mean adult occlusal force is about 400 to 800 n at the molar region , 300 n at the premolar region , and 200 n in the anterior region5
. oh and anusavice18 ( 2002 ) stated that clinical contact areas on the pontic and the adjacent abutments may generate variations in the mode of failure in all - ceramic 3-unit bridges and ceramic prostheses may fail at values far lower than the mean values measured intraorally .
the mean fracture loads for all designs were found lower than the mean maximum masticatory forces for molar region .
although luting can improve resistance of metal free restoration , fpds were not cemented on the abutments in this study .
this procedure may explain the low fracture resitance values . also , lack of a thermomechanical loading is another limitation . nevertheless , manufacturer suggested the use of ips e.max press system to remain limited with anterior and premolar regions , and there is no data about the use of this system at posterior region . since the aim of the present study was to compare the effects of different designs rather than to assess the clinical performance , providing standard conditions for all test designs would be enough for evaluation .
thus , the inherent limitations in this study should be considered . in the present study , cracks propagated obliquely through the gingival embrasure and pontic ( directing from the gingival embrasure to the occlusal contact area ) except for one specimen belonging to group 3 , at which the crack was between one of the connectors and pontic .
oh and anusavice18 ( 2002 ) and sundh , et al.29 ( 2005 ) reported results similar to those of this study .
the greatest incidence of fractures was observed in the premolar - molar connector for convex design .
the findings indicate that the direction of force transmission for this design is different than the other two groups .
the major drawback of specimens with geometry similar to that of real prosthesis is the difficulty to prepare specimens with reproducible dimensions27 .
the core / veneer thickness ratio and the properties of the veneering porcelain have been shown to affect the resistance of bilayered core / porcelain specimens8,11,29 .
the connector 's cross - section diameter , shape and position is founded to be important for the appropriate design of dental bridges10,18,19,28 . in the present study
, ips e.max bridges were fabricated by the same dental technician by using silicone molds to standardize the ceramic layer thickness . in the same way as observed for several in vitro studies , it is difficult to extrapolate the results of this study directly to a clinical situation , and data obtained from current study must be supported by clinical investigations .
within the limitations of this study , the following conclusions can be drawn : 1 .
the pontic designs were affected the fracture resistances of implant - supported all - ceramic fixed partial dentures ; 2 .
Output:
| objective : the purpose of this study was to compare the fracture resistance of implant - supported all - ceramic fixed partial dentures , which have three different pontic designs.material and methods : two implants were placed in a metal model simulating mandibular left second premolar and mandibular left second molar .
thirty standardized 3-unit all - ceramic fixed partial dentures with biconvex , convex or concave pontic designs were fabricated using ips e.max system ( n=10 ) .
afterwards , specimens were centrally loaded on the pontics until failure with a universal testing machine .
results were analyzed by kruskal - wallis and mann - whitney u tests at 5% significance level.results:the fracture resistance values of all - ceramic fixed partial dentures designed with biconvex , convex or concave pontics were 349.71 , 438.20 and 300.78 n , respectively .
there were no statistically significant differences between the fracture resistances of the groups ( p>0.05 ) , except for convex and concave groups ( p<0.05 and p=0.009 , respectively).conclusions : convex design showed the best mechanical properties as demonstrated by the high values of fracture resistance . |
PubmedSumm118794 | ***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 terms of esthetics , the anterior maxillary region in particular contributes to an enhanced smile and self - esteem of patients . to achieve a favorable outcome in periodontal and implant treatment , it is crucial to pay attention to morphological characteristics of periodontal tissue such as buccal bone and soft tissue thickness .
teeth roots are surrounded by two layers of cortical bone namely the outer cortical plate and alveolar bone proper ; cancellous bone is located between the two bone plates .
no cancellous bone is seen in regions with very thin buccal bone and these regions are mainly formed by bundle bone .
bundle bone is a tooth - related structure and is resorbed upon extraction of teeth .
a thick buccal bone supports the soft tissue and dental papillae and a thick tissue biotype is more resistant to recession [ 13 ] , provides superior implant esthetics and better conceals the prosthetic components of dental implants .
a thick tissue biotype plays a significant role in outcome of periodontal therapy such as root coverage procedures [ 6,8 , 9 ] .
hence , measuring the thickness of soft tissue and the underlying bone before implant placement is beneficial to prevent complications such as soft tissue recession , implant exposure and consequent psychological problems . when required , augmentation can be considered to achieve adequate contours .
spray et al , reported buccal bone thickness of 1.81.41 mm using a caliper .
katranji et al , reported 1.59 0.07 mm thickness using a boley gauge , and nowzari et al , reported 1.1230 mm thickness using cone beam computed tomography ( cbct ) scans . for soft tissue thickness ,
different techniques have also been used such as visual inspection , probe transparency , ultrasound and soft tissue cbct , in which the patients use a plastic lip retractor at the time of scanning for better visualization of soft tissue . also , cbct is a suitable method for visualization of teeth and soft tissue anatomy and has the advantage of superior diagnostic value and precise measurement of periodontal dimensions .
barriviera et al , and mller et al , reported the mean canine gingival thickness to be 0.2 and 0.7 mm , respectively , and fu et al , reported a mean labial soft tissue thickness of 0.5 mm in the maxillary anterior region .
variations in soft tissue and buccal bone dimensions have been speculated to be a result of differences in ethnicity , tooth positions and methodologies .
although determination of soft tissue and buccal bone thickness has been investigated by many authors , only a limited number of studies have assessed the association between these variables .
primary thickness of maxillary bone has a significant effect on the final level of soft and hard tissues following tooth extraction and also on selecting the appropriate method of implant placement ( immediate / early / delayed ) and prevention of subsequent complications .
therefore , this study aimed to measure the dimensions of soft tissue and the underlying bone in the anterior maxilla using cbct and to determine the association of bone and soft tissue thickness in the maxillary anterior teeth .
this cross - sectional study was conducted on patients requiring implant treatment in the department of periodontics and implantology .
sixty patients ( 35 women , 25 men ) with a mean ( standard deviation ) age of 37.510.1 years were selected .
the criteria of eligibility were as follows : presence of at least four teeth in the maxillary anterior region ( central incisors , lateral incisors and canines ) , absence of redness , inflammation or bleeding on probing , absence of attachment loss , probing pocket depth3 mm , absence of extensive subgingival restorations and tooth mal - alignment , no pregnancy or lactation and not taking medications affecting periodontal soft tissue .
written informed consent was obtained from all the patients who were then referred to a radiology center for cbct examination .
the cbct scans were taken with a planmeca promax 3d unit ( planmeca , helsinki , finland ) with 8080 mm field of view , total scanning time of 30 seconds at 8082 kvp and 12 ma , and an exposure time of 12 seconds.the scans were acquired in high - resolution mode with a voxel size of 0.16 mm , and the gray scale was 12 bits . romexis software ( planmeca , helsinki , finland ) was used for analysis of the images ( the observer was trained to use romexis ) .
the scans were displayed on an ea43fx viao laptop ( sony corporation , shanghai , china ) with the screen resolution of 1366768 pixels . for better visualization of soft tissue ,
the patients were asked to use plastic retractors in order to retract their lips and cheeks away from the gingival tissue before taking the scans ( fig .
the software provided frontal , axial and sagittal views of cbct scans . after exploring the 3d model by an observer ,
the model was oriented in order to find the best orientation to generate a 2d image .
the distances were measured on 2d images using the measurement tool of the given software . by using the cross - sectional views taken from the midline of each maxillary anterior tooth ( fig .
2 ) , measurement of facial bone and soft tissue thickness was performed at three different locations : at the crestal level and at 2 and 5 mm apical to the crest and perpendicular to the inner cortical plate at the site of each tooth .
the measurements were repeated on 15 randomly selected scans in order to estimate the intra - examiner reliability by calculating the intraclass correlation coefficient , which was found to be 0.7 .
the patient uses a plastic retractor before scanning line a shows the midline of the selected tooth the cross - sectional view of the tooth vertical line a indicates the long axis of the tooth .
horizontal lines b ( white ) from coronal to apical are : cementoenamel junction , crestal level , 2 mm apical to the crest and 5 mm apical to the crest , respectively ; horizontal line c ( gray ) indicates buccal bone thickness ; horizontal line d ( gray ) indicates soft tissue thickness ; vertical line e ( black ) shows the cementoenamel junction - crest distance for higher precision , thickness of hard and soft tissue was measured in three points ( at the crest and at 2 and 5 mm from the crest ) of each tooth and the mean of the three values was recorded as thickness of hard and soft tissue for each tooth .
data analysis was done using pearson s correlation coefficient to assess the correlation of hard and soft tissue thickness for each tooth .
anova was used to compare the thickness of hard tissue and soft tissue between different teeth .
results of data analysis in 330 anterior teeth of 60 eligible patients who required cbct scans showed that in the right and left canines , there was a mild correlation ( r=0.276 , p=0.282 ) between soft tissue and the underlying bone .
similar results were obtained in the right and left central incisors ( r=0.369 , p=0.332 ) between soft tissue and the underlying bone . in the right and left lateral incisors , no such association was observed ( table 1 ) .
there was a significant difference in the mean thickness of buccal bone in the studied teeth ( p= 0.0001 ) .
the bone thickness of the lateral incisors was greater than that of central incisors and canines .
concerning soft tissue thickness , the result was the same ( p=0.0001 ) and the least thickness was observed in the right and left canines .
no significant differences were found in cementoenamel junction - crest distance between the maxillary anterior teeth ( p>0.05 , table 2 ) .
association between soft and hard tissue thickness in the maxillary anterior teeth the meanstandard deviation of hard and soft tissue thicknesses ( mm ) and cementoenamel junction - crest distance ( mm ) in maxillary anterior teeth buccal soft tissue thickness in the aforementioned locations was different between the maxillary anterior teeth , and the soft tissue thickness was the least in the right canine .
buccal bone thickness at 2 and 5 mm below the crest differed between the maxillary anterior teeth and in the left lateral incisor , the mean thickness was more than in other areas ( table 3 ) .
the mean standard deviation of thickness of buccal soft and hard tissues ( mm ) in the selected locations in anterior maxillary teeth
the thickness of buccal bone and soft tissue and the correlation between them in the maxillary anterior region were evaluated in the present study . in 330 anterior teeth ,
the mean thickness of facial bone was 0.730.23 mm ( range : 0.131.8 mm ) and the mean buccal soft tissue thickness was 0.870.21 mm ( range : 0.401.7 mm ) . the mean cementoenamel junction
the results of the present study with respect to the mean buccal bone thickness were consistent with those reported by braut et al , who measured the mean buccal bone thickness in the maxillary anterior teeth using cbct , with the thicknesses in the central , lateral and canine areas at the crest being 0.47 , 0.54 and 0.45 mm , respectively .
additionally , the results of the present study were consistent with those reported by fu et al , who evaluated buccal bone and soft tissue thickness in 22 cadavers using cbct scans and showed the mean thickness to be 0.94 mm and 0.57 mm , respectively with moderate correlation between them ( r=0.4 ) .
nevertheless , in the study by fu et al , criteria such as healthy periodontium of the examined teeth were not included . in the present study
, a mild correlation was found between buccal hard and soft tissues in canines and central incisors ; however , such association was not detected for the lateral incisors . in a study by ghassemian et al , buccal bone thickness
the buccal bone thickness was 1.39 mm for canines , 1.28 mm for the lateral incisors and 1.22 mm for central incisors . in their study ,
the thickness of facial bone increased from the bone crest to the apical area whereas in the present study the thickest facial bone was detected at 2 mm below the crest and then at 5 mm apical to the crest and at the crest , respectively .
the reason for such finding might be the bone s tendency to become thin as a result of root convexity at the crest and possible fenestration in the apical region . variations in the reported measurements may also be related to racial disparities between the two different populations and their effect on soft tissue and facial bone thickness . in this study ,
soft tissue cbct was used in this study to measure labial soft tissue and bone thickness . in this method ,
the soft tissues of the lips and cheeks were retracted and a dark space was created between the lip and the buccal gingiva .
otherwise , the above - mentioned tissues would collapse on the facial gingiva and clear visualization of the soft tissue would not be possible .
high resolution , great precision in linear measurements and low radiation exposure are other advantages of this technique .
fu et al , reported no statistically significant differences between clinical and radiographic measurements of facial bone and soft tissue thickness .
it seems that cbct can be used as an objective method for labial bone and soft tissue assessments .
measuring tissue dimensions at three different levels was one of the advantages of this study . among these locations , the crestal position may be the most relevant since the crestal bone supports the gingival margin and if this bony structure resorbs , mucosal recession would ensue , contributing to esthetic problems .
the bone covering the root consists of two layers of cortical bone ( the outer cortical plate and the alveolar bone proper ) separated by a layer of trabecular bone . if the buccal bone is very thin , the trabecular bone may be completely missing and it may solely be comprised of bundle bone .
bundle bone is a tooth - dependent structure , which is resorbed after tooth extraction .
the mean thickness of facial bone was 0.81 mm in our study , which was the same as the value reported by chappuis et al .
the thin buccal bone in the maxillary anterior teeth has been shown in several studies ; therefore , an esthetic outcome may require adjunctive bone augmentation for most patients .
the characteristics of the soft tissue are determined by alveolar process dimensions , form , position and inclination of the teeth . in this study ,
also , patients taking medications affecting periodontium , pregnancy and any condition , which could affect soft and hard tissue thickness were excluded . eliminating these confounding variables was a strength of the present study .
meanwhile , there were also some limitations due to too many inclusion and exclusion criteria , which not only complicated the sampling procedure due to the limited number of eligible subjects , but also decreased generalizability of the study results to the general population .
the mean thickness of buccal bone and soft tissue in the anterior maxilla was < 1 mm and there was a mild linear association between them . the thinnest facial bone and soft tissue was detected in canine teeth .
Output:
| objectives : the purpose of this study was to determine buccal bone and soft tissue thicknesses and their correlation in the maxillary anterior region using cone beam computed tomography ( cbct).materials and methods : in this cross sectional study , 330 sound maxillary incisors in 60 patients with a mean age of 37.5 years were assessed by cbct scans . for better visualization of soft tissue , patients were asked to use plastic retractors in order to retract their lips and cheeks away from the gingival tissue before taking the scans .
measurements were made in three different positions : at the crest and at 2 and 5 mm apical to the crest . the cementoenamel junction
crest distance was measured . for data analyses ,
the pearson s correlation coefficient , anova and intraclass correlation coefficient were used.results:there were mildly significant linear associations between labial soft tissue and bone thickness in the canines and incisors ( r<0.40 , p<0.05 ) , but no association was found for the lateral incisors .
the mean thickness of buccal bone differed significantly in the maxillary anterior teeth , being greater for the lateral incisors ( p<0.05 ) . for soft tissue thickness
, the results were the same , and the least thickness was recorded for the canines .
there was a mild association between labial soft tissue and bone thickness in canines and incisors ( r=0.2 , p=0.3 ) , but no such linear association was seen for the lateral incisors.conclusions:the mean thickness of buccal bone and soft tissue in the anterior maxilla was < 1 mm and there was a mild linear correlation between them . |
PubmedSumm118795 | ***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: calcium pyrophosphate dihydrate ( cppd ) deposition in the cervical spine is an unusual cause of cervical spinal cord compression and myelopathy .
retro - odontoideal crystal deposits may lead to acute pseudogout and can be visualized as calcifications that surround the apex of the dens , and is therefore known as crowned dens syndrome ( cds).1
2 this entity may manifest itself in a variety of ways , but it usually presents as acute neck pain and stiffness.3
4 with disease progression , it may present as a mass - occupying lesion , causing progressive cervical spinal cord compression and myelopathy .
in general , noninfectious , nontumorous retro - odontoid cystic masses are exceedingly rare.5 they have mainly been described in the literature as synovial cysts , ganglion cysts , transverse ligament degeneration , or herniated discs.5
6
we present a rare case of retro - odontoid cppd resulting in cervical myelopathy that required surgical intervention .
our patient is an 83-year - old woman with a cystic lesion within the body of the dens , as well as a retro - odontoid mass , causing cervical spinal cord compression .
we successfully decompressed her lesion using a minimally invasive transoral decompression , under fluoroscopic visualization . the literature on cervical cppd
an 83-year - old female patient presented to our emergency department ( ed ) with progressive difficulty with balance and upper extremity clumsiness . while the balance difficulty had been progressive for some time , it had worsened drastically in the few weeks before presentation in the ed .
there was no history for joint swelling or inflammation in any of her major joints .
physical examination revealed hyperreflexia in her upper and lower extremities with bilateral positive hoffman and pathological clonus .
she also had diffuse paresthesias that was nondermatomal . computed tomography ( ct ) and magnetic resonance imaging ( mri ) scans
the ct scan revealed multilevel spondylosis without evidence of acute fracture or instability , and with a cystic lesion located within the body of the dens ( fig .
this lesion was noted to be hyperintense on t2-weighted mri and to be associated with a large extradural mass .
the mass caused significant cord compression , and was also associated with a bilobulated cystic mass that resulted in additional anterior compression , best appreciated on the axial mri ( fig .
2 ) .
sagittal and coronal computed tomography scan demonstrating cystic mass at the base of the dens , with multilevel cervical spondylosis .
magnetic resonance imaging ( t1 ( a ) and t2 ( b , c ) sequences ) demonstrating a retro - odontoid compressive mass with additional bilobulated cystic compression , with myelomalacia noted in the cord .
as our patient had progressive neurologic decline , we felt that surgical decompression was indicated .
as this was an elderly 83-year - old patient , we were concerned about the morbidity of either a posterior fusion followed by an anterior transoral approach or a posterior fusion alone . after a lengthy discussion with the patient and her family
, we elected to proceed with an anterior minimally invasive transoral aspiration of the cystic lesion to determine the etiology and to decompress the spinal cord within the canal .
the patient was positioned and intubated supine and we used the crockard transoral instrumentation system to maintain the exposure ( codman & shurtleff , inc .
the uvula was reflected out of the way using a suture and red rubber catheter through the nasopharyngeal cavity .
the retropharyngeal soft tissue was visualized , and using computer - assisted navigation , the correct trajectory and entry point was selected .
a small 5-mm incision was made into the retropharyngeal tissue anterior to the body of c2 .
then using fluoroscopy , a trochar was advanced into and through the body of c2 into the retro - odontoid pannus ( fig .
4 ) . histology revealed inflammatory cells with positively birefringent rhomboid crystals , consistent with the diagnosis of cppd .
intraoperative fluoroscopic images of the sleeved trocar placed through the retro - odontoid mass and into the cyst , and removal of the cystic material .
gross specimen : gelatinous material removed from cyst .
immediate postoperative magnetic resonance imaging ( mri ) , demonstrating successful cyst aspiration .
this resolved with supportive care and the patient was discharged home in stable condition , with resolution of her myelopathy including improved strength and sensation . at 6-month follow - up , the patient was walking with a cane only , and showed continued functional improvement .
a repeat mri at that time revealed complete resolution of the cysts and improved spinal canal diameter ( fig .
the patient was positioned and intubated supine and we used the crockard transoral instrumentation system to maintain the exposure ( codman & shurtleff , inc . ,
the uvula was reflected out of the way using a suture and red rubber catheter through the nasopharyngeal cavity .
the retropharyngeal soft tissue was visualized , and using computer - assisted navigation , the correct trajectory and entry point was selected .
a small 5-mm incision was made into the retropharyngeal tissue anterior to the body of c2 . then using fluoroscopy ,
a trochar was advanced into and through the body of c2 into the retro - odontoid pannus ( fig .
4 ) . histology revealed inflammatory cells with positively birefringent rhomboid crystals , consistent with the diagnosis of cppd .
intraoperative fluoroscopic images of the sleeved trocar placed through the retro - odontoid mass and into the cyst , and removal of the cystic material .
gross specimen : gelatinous material removed from cyst .
immediate postoperative magnetic resonance imaging ( mri ) , demonstrating successful cyst aspiration .
this resolved with supportive care and the patient was discharged home in stable condition , with resolution of her myelopathy including improved strength and sensation . at 6-month follow - up
, the patient was walking with a cane only , and showed continued functional improvement .
a repeat mri at that time revealed complete resolution of the cysts and improved spinal canal diameter ( fig .
cervical myelopathy that occurs as a result of compression at the craniocervical junction is uncommon and may be difficult to diagnose .
the etiology of the compression may include rheumatic disease , craniocervical tumors , synovial cyst and cppd deposition .
although more likely at advanced ages , in 2009 , unlu et al described a case of idiopathic cds in a young male , causing severe neck pain.7
8 clearly , the diagnosis of cppd should be considered in all patient populations , and may occur in the absence of significant risk factors .
most cases of cds arise in patients with known cppd disease . in 2001 , ryan et al noted that there was asymptomatic calcification of the periodontoid region in half of patients with a known diagnosis of chondrocalcinosis , suggesting a high incidence of involvement of these structures in cppd disease.9 interestingly , they noted that this deposition did not cause clinical disease in any of their patients . a 2004 case - control study by finckh et al described that cervical calcifications were found in 69% of cppd patients ( 24 of 35 ) , compared with only 11% in controls .
in addition , these patients were five times more likely to report neck pain.10 in 2008 , salaffi et al had similar results with 51% ( 25 of 49 ) having periodontoid calcifications in known cppd .
they continued further to describe subchondral cysts or erosion in 40% ( 10 of 25 ) of those patients.3 when clinically significant , the crystal deposition can present either acutely or insidiously , and mimics an inflammatory process.6 the correct diagnosis may be difficult , as cppd deposition can occur at any location in the spine .
resnick et al conducted a postmortem study of more than 1,000 spines and found cppd deposition in the intervertebral discs , interspinous and supraspinous ligaments , ligamentum flavum , posterior longitudinal ligament , sacroiliac joint , transverse atlas ligament , and posterior median atlantoaxial joint.10
11 there are numerous case reports showing cppd in various locations in the spine , supporting this .
atlantoaxial cppd deposition is best visualized on ct and plain film.1
12 it was initially described by bouvet et al as the crowned dens in 1985.13 ct is generally considered the most sensitive modality of visualizing periodontoid calcifications , and the existing literature suggests that diagnosis of cppd deposition is largely radiographic.14
15 the largest review of this syndrome was reported in the journal of bone and joint surgery in 2007 by goto et al.16 they reviewed 40 patients retrospectively that had characteristic calcium deposits visualized on ct scan ; however , none of these patients had histologic confirmation , and none displayed symptomatic disease . in the english literature ,
a limited number of cases of cds have had their diagnosis confirmed . in our case ,
the cppd diagnosis was verified via histology , which was especially important due to the absence of significant calcium deposition on ct scan .
a cystic odontoid mass , while also previously documented in cppd , usually lends itself to an alternate diagnosis , including synovial or ganglionic cysts , and transverse ligament degeneration.3 we attained confirmation with the classic weakly positively birefringent rhomboid crystals on histological analysis .
our mri findings were similar to others , with the compressing mass roughly isointense on t1-weighted , and very hyperintense on t2-weighted.17
18
19
20 as with any abnormal presentation , we recommend thorough radiographic studies to rule out other diagnoses .
treatment for cppd is symptomatic , and certainly nonsurgical modalities , including medications , should be attempted before surgical intervention when possible , with management tailored to both disease and patient . of the existing literature on cervical cppd disease , only a small fraction of cases required surgical intervention due to either pain , myelopathy , or type-2
odontoid fracture.19
21 retro - odontoid masses are difficult to reach safely with traditional surgical techniques .
whiteside approach allows access to the dens , but requires significant bony resection , and does not easily allow for instrumentation .
a transoral approach allows for direct access from the anterior clivus down to c3 or c4 .
it also reduces manipulation of the nearby neurovascular structures , compared with posterior and lateral approaches .
however , the approach introduces oral flora into the surgical field , increasing the risk of infection .
other complications include upper airway obstruction secondary to edema , velopalatine insufficiency , dental injury , tongue necrosis / edema , odynophagia , dysphagia , meningitis , pharyngeal cellulitis , and tmj syndrome.22
23
24 all of these approaches have significant morbidity and may require surgical stabilization before or after anterior decompression .
at the very least , they require a period of modified nutritional support and attention to aspiration and possible swallowing difficulties , as well as observation for potential infection . in 1996 , znkeler et al described seven cases of histology - confirmed cppd masses that were posterior to the odontoid process . these patients underwent a transoral transpharyngeal resection of the anterior arch of c1 , odontoid process , and the compressing mass.25 however , six of the seven patients required posterior fixation at a later time to treat instability.22
to minimize complications , different techniques have been used to reduce pharyngeal dissection , such as endoscopic - assisted and minimally invasive approaches .
our technique utilized a cannula to assist with decompression of the retro - odontoid space .
this minimizes the risks associated with a transoral approach , with the advantage of direct decompression of the mass .
it also allows for resection of the mass with minimal bone resection , which may prevent late instability .
the limitations are that this approach is technically demanding , is reliant on ideal intraoperative imaging , and requires a mass that can be removed via the cannula . despite the previously stated limitations ,
this approach has proven to be a viable alternative for direct surgical aspiration through the transoral approach , and avoids the need for surgical stabilization .
while cppd is a rare cause of cervical spinal cord compression , deposition may occur at a variety of locations in the craniocervical junction , and should be included in the differential diagnosis of cervical inflammatory diseases.26
27
28
29
30
31 advanced imaging is required to correctly identify the etiology of the compression , and may offer some clues to the diagnosis , particularly if the dens is surrounded by calcifications .
we present a case of cppd in the retro - odontoid space that caused significant spinal cord compression .
we utilized novel minimally invasive transoral aspiration to establish the diagnosis , and affect appropriate decompression with minimal morbidity .
jefferson r. wilson , michael g. fehlings
division of neurosurgery and spinal program , university of toronto , toronto , ontario , canada in this article , the authors report on their management of an elderly patient with a rare form of cervical compressive myelopathy secondary to retro - odontoid calcium pyrophosphate dehydrate ( cppd ) deposition . with an overall goal of achieving decompression of the spinal cord , while minimizing the risk of serious morbidity to the patient , the authors chose to perform a transoral aspiration of the associated epidural cystic mass . although the patient 's immediate postoperative course was complicated by respiratory distress syndrome , the authors reported good clinical and radiological outcomes at follow - up .
the presented case presents a variety of challenges both at a disease and patient level .
although the deposition of cppd is a common cause of peripheral joint arthropathy , it is a rare cause of cervical myelopathy.1
2 as a result , in comparison to cervical spondylotic myelopathy or myelopathy secondary to ossification of the posterior longitudinal ligament , the natural history and ideal treatment approach to cppd related myelopathy remains more poorly defined . with respect to patient factors ,
the advanced age of the discussed patient requires the surgeon to choose an operative approach that balances the desire for complete and permanent spinal cord decompression with the potential for complications and morbidity . in accordance with these principles ,
the surgical approach selected effectively minimized the extent of potentially destabilizing tissue dissection and bony resection , obviating the need for posterior placed instrumentation .
furthermore , the cyst aspiration resulted in significant spinal cord decompression with concurrent improvement in symptoms .
first , advancing a trochar in the midline through diseased bone toward the spinal canal carries the risk of iatrogenic spinal cord injury .
in addition , the chosen method would be limited to those lesions with a major cystic component .
second , the durability of the chosen treatment approach remains in question . as seen on the postoperative imaging ,
while the epidural lesion is reduced in size as compared with preoperatively , it does remain present . over time
, potential reaccumulation of cyst contents resulting in recurrent symptoms of myelopathy would necessitate the revisiting of potential surgical options . even if a similar , minimally invasive approach is used , this would expose an even older patient to the risks of repeat surgery and hospital admission .
moreover , cppd is often associated with degenerative atlantoaxial instability , and continued motion at c1c2 could also predispose the patient to recurrent cyst formation .
that said , at 6 months follow - up , the patient remained clinically and radiologically stable , indicating that the chosen treatment approach may be sufficient throughout the long term . in summary ,
the authors are to be congratulated for their innovative approach to the treatment of a rare form of myelopathy in an elderly patient .
although this approach may not be suitable for a younger individual , due to potential concerns surrounding durability , it achieved the goals of attaining cord decompression while minimizing patient harm . with the overall aging of the population ,
we are likely to see an expanded use of similar minimally invasive techniques when treating spinal disorders amongst the elderly in the coming years .
ebsj welcomes the case presentation and the thoughtfully rendered concerns about the technique described by drs .
the main purpose of including this article rested in the increasing number of elderly patients who present with disabilities secondary to severe spinal disorders , usually with considerable delays in recognition .
the crowned dens syndrome is an example . by showing pertinent images of this case , recognition of this condition or other storage diseases
ebsj does not endorse the technique described because no conclusions can be drawn from a single case , especially as disease recurrence is a very distinct possibility , as pointed out by drs .
furthermore , this patient quite evidently has diffuse subaxial spondylosis with likely contributions on healthy spinal cord function , rendering determination of clinical success over time quite difficult .
Output:
| study design case report and review of the literature .
objective a retro - odontoid mass is a rare cause of cervical compression and myelopathy .
the differential diagnosis includes the following : metastatic disease , primary tumor , collagen disorder , or inflammatory disease .
calcium pyrophosphate dihydrate ( cppd ) deposition has been referred to as crowned dens syndrome when there are periodontoideal calcifications .
there are only a few reported cases where cppd presents as a cystic retro - odontoid mass in the atlanto - dens interval . in previous descriptions of surgical intervention , transoral resection of the mass
is associated with significant morbidity and usually requires stabilization .
the objective of this article is to report a case of an unusual presentation of cppd disease of c1/c2 , where we used a novel , minimally invasive surgical technique for decompression without fusion .
patients and methods an 83-year - old female patient presented with progressive cervical myelopathy over a 3-month period . computed tomography and magnetic resonance imaging demonstrated a cystic odontoid mass with a separate retro - odontoid compressive mass . a novel , minimally invasive transoral aspiration was performed .
histologic confirmation of cppd was obtained .
results postop imaging showed satisfactory decompression , which was maintained at the 6-month follow - up .
this correlated with clinical improvement postop and 6-month follow - up .
conclusion cppd in the atlanto - dens interval may present as a cystic retro - odontoideal mass and should be included in the differential .
we used a transoral minimally invasive approach to aspirate the cyst .
this novel technique avoided the need for a stabilization procedure or morbid transoral resection and provided excellent results immediately and at 6 months . |
PubmedSumm118796 | ***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: tooth size discrepancy ( tsd ) is different among the sizes of the individual teeth . for ideal occlusion
, teeth in both arches should be proportional in size , significant tsds prevent an ideal occlusion being produced at the end of orthodontic treatment .
tooth size analysis was presented by bolton in 1958 , and the anterior segment ratio was derived to be 77.2 0.22% and 91.3 0.26% for the total arch ratio .
bolton 's ratio has been suggested as the seventh key for an ideal occlusion , as it plays an important role for ideal occlusion .
overall , tsds relate to all teeth excluding permanent second and third molars , whereas anterior tsds involve the six anterior teeth from left side canine to the right side .
prevalence of an overall tsd has varied from 4% to 11% among the patients undergoing orthodontic treatment .
anterior tsds , have a prevalence between 17% and 31% among orthodontic patients , that is similar to the prevalence of 20.5% in non - orthodontic patients .
the prevalence of tsds are more common in class ii division 1 malocclusions and in class iii malocclusions .
studies have found smaller tooth size ratios in women than in men , but the differences at 0.61.0% that were not significant .
found that black people had the highest overall tooth size ratios ( 93.4% ) , followed by hispanics ( 92.3% ) and whites ( 91.2% ) .
there are various methods to measure the mesiodistal width of teeth such as conventional fine pointed caliper or digital caliper , measuring photocopies of casts with a caliper , divider , etc .
the purpose of this study was to evaluate the bolton ratio in a north indian population with different malocclusion groups .
this cross - sectional study was carried out at various dental clinics at lucknow in north india .
orthodontic diagnosis and treatment planning requires the patient 's history , extra and intra - oral examination , analysis of diagnostic records comprising of orthodontic photographs , radiographs and study casts .
tooth size is the sum of the mesiodistal widths of the maxillary and mandibular teeth that is measured in this study over the study casts . a thorough examination of all the study casts was done .
110 out of 150 study casts [ age : female ( 14.2 1.5 years , male ( 13.9 2.3 years ) ] were filtered based upon the inclusion and exclusion criteria [ table 1 ] .
study casts were further divided into three groups : group i ( angle 's class i , n = 40 ) , group ii ( angle 's class ii , n = 50 ) and group iii ( angle 's class iii , n = 20 ) according to angle 's classification of malocclusion . the mesiodistal widths of all maxillary and mandibular teeth from right permanent first molar to left permanent first molar were calibrated with the use of a digital caliper .
the readings were used to calculate the anterior and total bolton ratios and the data were analyzed using spss-14 .
mean and standard deviation ( sd ) were calculated for anterior and total bolton ratios for the whole sample and for all the three groups individually .
the anova test was used to compare the three groups with each other and with the bolton 's proposed norms for total and anterior bolton ratios .
a mean total bolton ratio of 91.36 2.13 and a mean anterior bolton ratio of 78.14 4.09 were found for the complete sample [ table 2 ] . the minimum total bolton ratio calculated for group ii patients while the highest ratio was calculated for group i patients .
anova and tukey 's test failed to show any significant difference in the total bolton ratios of different sample groups ( p > 0.05 ) [ table 3 ] . the minimum anterior bolton ratio calculated for group i patient while the highest ratio was calculated was for group ii patient [ table 2 ] .
anova and tukey 's test showed a significant difference for anterior bolton ratios between bolton 's proposed norms and group ii patients and also between group i and group ii patients ( p < 0.01 ) [ table 4 ] .
mean ( sd ) of tooth size ratios for different malocclusion groups anova and tukey 's test for total bolton 's ratios anova and tukey 's test for anterior bolton 's ratios
in order to achieve excellence in orthodontic finishing , clinician should be familiar to the discrepancies in tooth size at the initial diagnosis and treatment planning stages .
a good occlusion depends on a correct ratio between the dental masses in the maxillary and mandibular arches . by measuring the greatest mesiodistal width of each permanent tooth , including all the teeth since the 1 left to the 1 right permanent molar a ratio of 91.3% 1.91
when only the six anterior teeth of the arch were evaluated , the ratio was 77.2%1.65 ) . for bolton ,
patients with means of anterior and total tooth size ratio above or below 2% of the values established in his research , should be classified as having tsd .
the mean sd for overall and anterior tsd ratios in the present sample were 91.36 2.13 and 78.14 4.09 , respectively , similar to the recent study in the lybia . in our study
, a comparison was made between tsd in class i , ii and iii patients on study cast based on angle 's classification of malocclusion .
the mean total ratio for the whole sample was 91.36 2.13 which is very close to bolton 's proposed ideal ratio .
however , the anterior ratio for the whole sample was found to be 78.14 4.09 , which is higher than bolton 's proposed ideal ratio , which reflected a greater mesiodistal widths in the mandibular anterior segment in our population sample . in group
i patients , the mean total ratio calculated was 91.73 3.60 and the mean anterior ratio calculated was 76.89 4.16 , both of which are close to bolton 's proposed ideal ratios .
similarly , the total mean ratio calculated for group ii ( 90.77 2.13 ) and group iii ( 91.33 2.32 ) patients and the anterior mean ratio for group iii patients ( 77.51 5.64 ) was in close agreement with bolton 's proposed ideal ratios .
a significantly higher ( p < 0.05 ) mean anterior ratio ( 81.10 5.01 ) for group ii patients was found and this reflects a tendency toward wider mesiodistal dimensions in the mandibular anterior segment in our study sample . there was a significant difference in the anterior tooth ratios between group i and group ii patients .
no significant difference was found between group i and group iii or group ii and group iii patients .
no correlation was found between angle 's classification of malocclusion and bolton discrepancy as shown by crosby and alexander .
uysal and sari compared interarch tsd in 150 untreated , normal occlusion subjects and 560 patients of four different malocclusion groups .
al - khateeb and abu alhaija found no statistically significant differences in bolton 's ratios between the different malocclusions .
their sample consisted of 140 orthodontic models of school children aged between 13 and 15 years of jordanian origin . in
this study found that group ii patients had higher mesiodistal width in mandibular anterior region and group ii includes angle 's class ii malocclusion patients , but the study did by neamah , they found that excess mesiodistal width in maxillary anterior region in skeletal class ii subjects .
ahir and shah studied a gujrati population and found mandibular excess in angle 's class i and class iii malocclusion .
the results of the presentstudy are in partial agreement with some of the above studies considering the fact that no significant difference was found between bolton 's norms and tooth size ratios in group i and group iii patients . however , unlike other studies , group iii did not show a significantly higher anterior tooth ratio as compared to group , i patients .
the observation of this study was that in group ii that includes angle 's class ii malocclusion subjects showed a significantly higher anterior ratio , indicating wider mandibular teeth in angle 's class ii malocclusion or smaller teeth in maxillary arch .
mean anterior tsd for angle class ii subjects was significantly greater compared to bolton 's mean anterior ratiothere was relatively more tooth size excess in the mandibular anterior or smaller teeth in the anterior maxillary arch in selected samples of malocclusions ( north indian population ) as compared to bolton 's original sample of excellent occlusions .
mean anterior tsd for angle class ii subjects was significantly greater compared to bolton 's mean anterior ratio there was relatively more tooth size excess in the mandibular anterior or smaller teeth in the anterior maxillary arch in selected samples of malocclusions ( north indian population ) as compared to bolton 's original sample of excellent occlusions .
Output:
| objective : the objective was to evaluate the bolton ratio in a north indian population in lucknow with different malocclusion.materials and methods : totally , 110 study cast [ age : female ( 14.2 1.5 years , male ( 13.9 2.3 years ) ] were taken from the patients undergoing orthodontic treatment and subjects were divided into three groups : group i ( angle 's class i , n = 40 ) , group ii ( angle 's class ii , n = 50 ) and group iii ( angle 's class iii , n = 20 ) according angle 's classification of malocclusion . the mesiodistal widths of all maxillary and mandibular teeth from right first molar to left first molar were measured with a digital caliper to calculate the bolton ratio .
the readings were then used to compute the anterior and total bolton ratios .
anova and tukey 's test were used for the statistical analysis.results:a mean total bolton ratio of 91.36 2.13 and a mean anterior bolton ratio of 78.14 4.09 were found for the sample , significantly higher mean anterior tooth ratios were found for group ii ( angle 's class ii ) patients ( p < 0.01 ) .
all other ratios were within close range of bolton 's norms.conclusions:angle's class ii patients showed a tendency toward wider mesiodistal widths of teeth in the mandibular anterior region or smaller tooth sizes in the maxillary anterior region . |
PubmedSumm118797 | ***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: nephrotic syndrome has an incidence of three new cases per 100 000 population each year in adults and about 2/100 000 in children .
corticosteroids ( specifically prednisolone [ pdn ] ) form first line of treatment for nephrotic syndrome in children and it is used for prolonged period and sometimes repeatedly for relapses . although there is lack of clinical guidelines for management of nephrotic syndrome in adults , it is managed by controlling edema , using angiotensin - converting enzyme inhibitors with controversial role of steroids . the response rates to corticosteroids in adult minimal change disease is variable ( remission in 37% to 50% within four weeks , 51% to 76% within eight weeks , and 76% to 97% within 16 weeks with failure in 10% and relapse in about two third patients ) as compared with similar disease in children .
cyclophosphamide , cyclosporine , chlorambucil , and other immunosuppressive have been used for patients with either steroid - resistant or frequently relapsing nephrotic syndrome .
immunosuppressive therapy for nephrotic syndrome is not without adverse effects which such as infection , malignancy , peptic ulceration , diabetes mellitus , infertility , kidney failure , bone marrow suppression , hypertrichosis , and alopecia .
important side effects of steroids in adults include fall in bone mineral content ( bmc ) , cushingoid appearance , and increased blood pressure . in children
particularly , corticosteroids have known adverse effects such as obesity , impaired growth , hypertension , impaired glucose tolerance , osteoporosis , cushingoid symptoms , and adrenal suppression and these are more prevalent in those children who relapse frequently requiring multiple courses of corticosteroids .
deflazacort ( dfz ) is an oxazoline derivative of pdn with anti - inflammatory and immunosuppressive activity .
the potency ratio of dfz vs pdn is estimated to be 1.28 ( 6 mg of dfz : 5 mg pdn ) .
the use of dfz in duchenne muscular dystrophy , juvenile idiopathic arthritis ( previously , juvenile chronic or rheumatoid arthritis ) , chronic inflammatory diseases in adults , renal transplantation,[1416 ] various hematological disorders ( non - hodgkin 's lymphoma , idiopathic thrombocytopenic purpura , etc . ) , drug - resistant epilepsies in children , and type 1 autoimmune hepatitis is found to be as efficacious as other steroids with less worrying adverse - effect profile .
although therapeutic effects are inseparable from adverse metabolic effects of steroids , the goal of corticosteroid therapy should be to achieve maximum clinical benefit with minimum side effects .
dfz appeared to have almost similar efficacy with fewer side effects for various immune - mediated diseases as compared with pdn or other steroids . in management of nephrotic syndrome ,
thus , it will be prudent to find a drug with similar efficacy but fewer side effects for patients with nephrotic syndrome .
objective of this systematic review is to evaluate the efficacy and toxicity of dfz for nephrotic syndrome and whether dfz is effective for inducing and maintaining remission in patients with nephrotic syndrome , similar or more effective than other steroids or therapies ? and have fewer side effects as compared to other steroids or therapies .
the review included randomized control trials ( rct ) comparing dfz as compared with placebo or other therapies in patients with nephrotic syndrome for efficacy ( remission or not , time to remission , number of relapses ) and adverse effects .
the cochrane central register of controlled trials ( central ) 2011 , issue 2 was also searched with words
we searched asn ( american society of nephrology ) , wcn ( world congress of nephrology ) , and era - edta ( european renal association - european dialysis and transplantation association ) conference proceedings available online for additional relevant study .
two authors individually screened abstract of studies found in search to locate studies eligible to be included in review .
both the review authors assessed for risk of bias in included studies related to random sequence generation , allocation concealment , blinding , incomplete outcome data , selective reporting , and other sources of bias .
the search of asn , wcn , and era - edta conference proceedings did not reveal any additional study .
full texts of three studies were assessed for eligibility and all three were selected for qualitative synthesis as per inclusion criteria of review.[2123 ] one crossover rct was excluded .
the corresponding authors of two included studies ( olgaard et al . and liern et al . )
were contacted through email for additional information and we got more unpublished data from liern et al . but not from olgaard et al .
all three studies finally selected for the review were randomized controlled trials and published in english , except for study by liern et al . which was published in spanish but the english version was also available .
the included studies involved a total of 91 participants . only children were included in study by broyer et al . and liern et al .
enrolled steroid - dependent nephrotic patients and details of nephrotic state was not defined in study by liern et al .
all included studies were conducted at one center each ; broyer et al . in france , olgaard et al . in denmark , and liern et al . in argentina .
the intervention received were dfz and pdn ( on dose ration of 1.2 : 1 ) in studies by broyer et al . and olgaard et al . and dfz and methylprednisolone ( mpd ) ( in dose ratio of 1.5 : 1 ) in study by liern et al .
broyer et al . recorded time to achieve remission , number of relapse during study period , bone mineral density of lumbar spine , growth velocity , and clinical signs of cushing syndrome .
olgaard et al . mainly evaluated the effect of dfz vs pdn on bone metabolism by measuring bmc of spine , arm , forearm , and mandible .
mainly evaluated recovery of different immunoglobulin sub - classes in patients with ns treated with mpd vs dfz .
flow diagram of study selection characteristics of included studies evaluating deflazacort in patients with nephrotic syndrome quality measures of included studies are shown in table 2 .
liern et al . did not describe about allocation concealment , whereas in rest of the two studies , it was done properly .
subjects were blinded in all three included studies and investigators were also blinded in studies by broyer et al . and olgaard et al . in study by liern et al .
, there was no drop out ; in study by broyer et al . , drop outs were similar in both groups and reason were given by authors .
no study protocol was available for any of the study , so it is difficult to comment on selective reporting in included studies . none of the included studies were stopped early .
quality measures of included randomized controlled trials summaries of results of all three included studies are illustrated in tables 3 and 4 . because the participants ( broyer et al . included steroid dependent nephrotic children , olgaard et al .
included frequently relapsing nephrotic children ) reported outcome measures ( measurement of effectiveness and metabolic effects of steroids in study by broyer et al . ,
evaluation of osteoporosis in study by olgaard et al . , and it was assessment of recovery of immunoglobulins in nephrotic patients in study by liern et al . )
varied markedly , we focused on describing the studies , their results , their applicability , and their limitations , and on qualitative synthesis rather than meta - analysis .
regarding efficacy of dfz in nephrotic syndrome as compared with other steroids , the mean time for attaining remission was similar in dfz group and other steroids in studies by broyer et al . and liern et al .
, the 24-hour urinary protein decreased significantly among both groups of dfz and pdn without significant difference between the drugs [ table 3 ] .
mean number of new relapses during one year of study period were significantly less in dfz group as compared with pdn group in the study by broyer et al .
similarly , the patients free of relapse during study period were significantly more in dfz group in the same study .
the mean numbers of new relapses during study period were not significantly different in study by liern et al . and such data are not available in study from olgaard et al . regarding side effects of steroids in nephrotic syndrome , the mean growth velocity was not significantly different between dfz and pdn in study by broyer et al .
and such data are not available in other two included studies [ table 4 ] . in study by broyer et al . , the mean bmc of spine changed significantly from baseline in pdn group but not in dfz group . in the same study ,
mean decrease in bone density was -12% and -6% in pdn and dfz group , respectively , although it was not statistically significant [ table 4 ] .
total bmc of lumbar spine and mandible decreased significantly from baseline in both dfz and pdn group in study by olgaard et al . , but the it was significantly less in dfz as compared with pdn group for lumbar spine but not for mandible [ table 4 ] .
the mean decrease in bone density / year in lumbar spine was significantly more in pdn group as compared with dfz group in the same study .
data on bmc were not available from study by liern et al . change in body weight was not significantly different between groups in studies by broyer et al . and liern et al .
but in study by olgaard et al . , weight decreased significantly in dfz group as compared with pdn group [ table 4 ] .
blood sugar levels were not significantly different between the groups in any of included studies .
the blood pressure changes were also not significantly different between the groups in any of included studies , except in study by olgaard et al . where diastolic blood pressure increased significantly in pdn group as compared with dfz group .
urinary calcium excretion increased significantly in pdn group as compared with dfz group in study by olgaard et al . , but there was no difference in urinary calcium excretion between the groups in study by broyer et al . and such data were not available in study by liern et al .
cushingoid features were not significantly different among dfz and other steroids in studies by broyer et al . and liern et al .
study characteristic and efficacy of deflazacort as compared to other steroids in nephrotic syndrome side effects of deflazacort as compared to other steroids in nephrotic syndrome
there is lack of sufficient evidence for comparing dfz with other steroids in relation to efficacy and adverse effects in patients with nephrotic syndrome .
the identified studies were small in number which seems insufficient to address all objectives of the review .
methodologies of included studies varied : all were rct with proper allocation concealment in two and it was not described in one study ; method of random sequence generation described in two studies ; participants were blinded in all and in two studies investigators were also blinded .
it is difficult to comment on selective reporting in studies as study protocol was not available for any of the study .
the available evidence suggest that dfz at equipotent dosage appears to be of similar ( better in one study ) efficacy as compared with pdn or mpd for inducing remission or decreasing proteinuria in patients with nephrotic syndrome .
adverse effects of dfz as compared with other steroids in patients with nephrotic syndrome were not consistent except for effect on bmc where dfz had favorable effects as compared with pdn .
effects on blood pressure , weight change , urinary excretion of calcium , and cushingoid features were not consistent between the studies . the possible explanation for this discrepancy may be difference in participants among studies , e.g. , broyer et al
for this review , the search strategy was broad without any limitations making likelihood that all relevant studies were identified .
two authors were involved individually for study selection and data retrieval and any discrepancy was resolved by discussion .
the corresponding authors of two included studies were contacted through email for additional information and we got some additional data from one .
the quality of included studies varied [ table 2 ] and there were some missing data related to outcome of review .
there was inconsistency of results regarding adverse effect profile of dfz as compared with other steroids .
a crossover rct , excluded from review , compared the treatment sequence of dfz - prednisone or prednisone - dfz in ten adult nephrotic patients and reported similar efficacy for both the treatment sequence .
avioli described the equipotent ratio of dfz to pdn as 1.28:1 , although equipotency between dfz and pdn varies in different conditions , e.g. , 1.2:1 for nephrotic syndrome , rheumatoid arthritis , and juvenile chronic arthritis ; 1.4 :1 for asthma and polymyalgia rheumatica .
two of the included studies , where dfz was compared with pdn , used the 1.2:1 ratio .
scudeletti et al . showed that a single oral dose of dfz induced t cell depletion and affected the ratio of helper , inducer / suppressor , cytotoxic t cells for up to 72 hours , while they returned to baseline levels within 24 hours following pdn .
this change in ratio of t4/t8 cells had been consistently found in patients treated daily with dfz , while it was not consistent during pdn therapy .
these changes in t lymphocyte subsets by dfz were also noticed in patients after kidney transplantation .
this difference in the immune - modulatory effect of dfz and pdn may explain the different efficacy and side - effect profile in subjects with nephrotic syndrome as dysfunction of t lymphocytes is suspected to be one of the underlying mechanisms in nephrotic patients . a cochrane review on corticosteroid therapy for nephrotic syndrome in children by hodson et al
. included one study related to dfz which also is the part of our review .
dfz is costlier and treatment with dfz 36 mg daily for six months costs 235 ( pounds 235 ) compared with 19 ( pounds 19 ) for pdn 30 mg daily .
there were insufficient studies comparing dfz and other steroids for nephrotic syndrome . by reviewing the available evidence , dfz appeared to be of similar efficacy for nephrotic patients as compared with other steroids and had favorable effect on bmc of spine but there were inconsistent results regarding other side - effect profile of dfz as compared with other steroids .
there was lack of evidence to recommend / not dfz in place of pdn for treating nephrotic syndrome .
this review highlights the need for larger randomized controlled trials with sufficient follow - up period to evaluate effectiveness and adverse effect profile of dfz as compared with other steroids in subjects with nephrotic syndrome , especially children with first episode of nephrotic syndrome .
further research is also needed for defining accurate equipotency ratio of dfz as compared with pdn .
there were insufficient studies comparing dfz and other steroids for nephrotic syndrome . by reviewing the available evidence , dfz appeared to be of similar efficacy for nephrotic patients as compared with other steroids and had favorable effect on bmc of spine but there were inconsistent results regarding other side - effect profile of dfz as compared with other steroids .
there was lack of evidence to recommend / not dfz in place of pdn for treating nephrotic syndrome .
this review highlights the need for larger randomized controlled trials with sufficient follow - up period to evaluate effectiveness and adverse effect profile of dfz as compared with other steroids in subjects with nephrotic syndrome , especially children with first episode of nephrotic syndrome .
further research is also needed for defining accurate equipotency ratio of dfz as compared with pdn .
Output:
| patients with nephrotic syndrome require steroids for long time and sometimes repeatedly resulting in various adverse effects .
deflazacort ( dfz ) had been described as equally effective and with fewer side effects as compared with other steroids .
this review evaluates the literature on efficacy and toxicity of dfz as compared with other therapies for nephrotic syndrome . a systematic review of pubmed database and cochrane central register of controlled trials with last search date of 20th april 2011 .
search terms included
nephrotic and deflazacort without any limitations .
randomized control trials comparing dfz vs placebo or other therapies in subjects with nephrotic syndrome were included .
two authors extracted data independently .
three studies meet inclusion criteria and data were synthesized qualitatively .
the limited evidence suggested that dfz appeared to be equally effective in inducing remission or decreasing proteinuria in patients with nephrotic syndrome .
it caused significantly less decrease in bone mineral content ( bmc ) in spine as compared with prednisolone .
the results related to weight change , blood pressure change , cushingoid symptoms , and urinary calcium excretion were inconsistent between included studies . by reviewing the available limited evidence , dfz appears to be of similar efficacy for nephrotic patients , but there were inconsistent results regarding side effect profile of dfz as compared with other steroids except for decrease in bmc where dfz was better .
there is need for larger randomized controlled trials to evaluate effectiveness and adverse effect profile of dfz as compared with other steroids in nephrotic syndrome . |
PubmedSumm118798 | ***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: one of the causes of sperm dna damage and male infertility is the presence of unbalanced reactive oxygen species ( ros ) .
os occurs when ros production exceeds the body 's own natural antioxidant defences , resulting in cellular damage .
there are three different forms of ros : the primary form of ros including superoxide anion from which secondary ros can be derived directly or indirectly , the secondary form of ros including hydrogen peroxide , hydroxyl radical , and peroxyl radical , and the tertiary form of ros represented by nitrogenous compounds ( peroxynitrous acid , nitroxyl anion , peroxynitrile , and nitrous oxide ) .
human ejaculate consists of different types of cells such as mature and immature spermatozoa , round cells at different stages of the spermatogenic process , leukocytes , and epithelial cells .
however , it is implied that leukocytes contribute the most to os because compared with spermatozoa the rate of ros production in leukocytes is 1000 times greater .
extrinsic source of ros as opposed to the intrinsic source from sperm which correlates strongly with different sperm parameters such as dna fragmentation [ 35 ] .
in addition , os in semen may be secondary to a lot of other exogenous sources such as environmental pollution by heavy metals and lifestyle factors such as obesity , smoking , and alcohol abuse but also some medical conditions such as varicocele , spinal cord injury , and genitor - urinary tract infections .
it also describes a significant increase in seminal ros production in men older than 40 years ; despite these higher seminal ros levels in older men , no increase in the seminal leukocyte concentration was found .
low and controlled concentrations of ros play an important role in sperm physiological processes such as capacitation , hyperactivation , acrosome reactions , and signaling processes necessary for fertilization .
moreover , an increase in os significantly impairs sperm function ; these impairments have resulted in male infertility .
in fact , ros can damage sperm membrane resulting in poor motility and impaired sperm - oocyte fusion .
as previously described , os can also be linked with sperm dna damage which may result in poor embryo development , miscarriage , and infertility .
ros attack the integrity of dna in sperm nucleus resulting in base modification , strand breaks , and chromatin cross - link .
sperm chromatin has a highly condensed and organized structure that helps to protect it from oxidative damage , making it very resistant to dna damage .
however , when compaction is poor and chromatin protamination is incomplete sperm dna is more vulnerable to os .
several studies have pointed out a central role of oxidative stress , leading to the formation of ros , in the etiology of sperm dna damage [ 7 , 1113 ] .
these findings extended earlier original observations on the role of oxidative stress in the etiology of male infertility [ 14 , 15 ] .
high ros concentrations in infertile men have been associated with dna fragmentation and poor chromatin packing .
some studies have shown that the administration of antioxidant may improve sperm dna integrity [ 16 , 17 ] and pregnancy outcomes ; therefore , there is a clear need for andrology laboratories to be able to identify sperm os .
a reduction of some semen parameters is frequently seen in man with os ; also hyperviscosity of seminal plasma and ureaplasma urealyticum infections are associated with increased ros production . as previously described , the presence of a large number of round cells can imply os caused by leukocytospermia besides abnormal sperm morphology related to excess residual cytoplasm and cytoplasmic droplets .
fertile healthy men with normal seminal parameters almost consistently have low levels of dna breakage , while infertile men with abnormal seminal parameters have higher fraction of sperm dna damage .
the aim of our study was to evaluate any possible relationship between the unbalance of oxidative stress in human semen assessed by oxisperm with the presence of an increased sperm dna fragmentation estimated by sperm chromatin structure assay ( scsa ) and high concentration of round cells .
the study sample included 56 randomly selected males from couples suffering from male infertility between october 2013 and february 2014 .
male factor infertility is defined as the inability of a couple to conceive a child after one year of unprotected sexual intercourse with a female that has a normal reproductive history , normal ovulation , and tubal patency .
male factor infertility patients included in the study consisted of both men with normal sperm parameters according to world health organization ( who ) criteria and men who had at least one defect in either count , motility , or morphology .
samples with severe dispermy ( sperm concentration minor of 2 10/ml ) were not included ; a minimum amount of sperm to reliably perform the various sperm assays is required .
semen samples were produced by masturbation after a period of 27 days of sexual abstinence .
after liquefaction at 37c , standard comprehensive semen analysis of the evaluation of macroscopic and microscopic parameters was performed according to who 2010 guidelines .
both scsa and oxisperm require an extremely small fraction of the total ejaculate with a reasonable sperm count .
an aliquot of semen was used for oxidative stress estimation by oxisperm ( halotech dna , madrid , e , eu ) . for scsa
, another semen aliquot was diluted in isotonic phosphate buffered saline ( pbs ) for adjusting sperm concentration to 2 10/ml and frozen in liquid nitrogen ; cryoprotectants are not needed .
samples with sperm concentration minor of 5 10/ml were diluted in proportion 1 : 1 semen - pbs .
os levels from n1 ( low ) to n4 ( high ) were assessed using oxisperm kit that measures an excess of superoxide anions present in the ejaculate .
the test is based on the nitro blue tetrazolium assay ( nbt ) , a well - established laboratory technique used to quantify neutrophil function and cellular oxidative metabolism .
the nbt test has been shown to be useful in quantifying both leukocytes and ros production . in oxisperm kit nitro
blue tetrazolium is in the form of a reactive gel ( rg ) ; water soluble tetrazolium salt incubated with cells is converted by the action of superoxide anions into an insoluble blue crystal known as formazan .
these crystals are trapped within the cell but can be released by solubilization in a solvent solution ; they produce and increase color intensity in the rg from yellow to different levels of purple - blue which can be easily and comparatively quantified by eye through the use of a color scale .
the intensity of the color is related to the level of os in the sample ( figure 1 ) .
rg was liquefied in a water bath at 90c for 5 minutes and then the rg temperature was reduced to 37c .
the rg was mixed with the semen sample in an eppendorf tube in order to have a final sperm concentration of 1 10/ml ( volume proportion 1 : 1 semen - rg ) ; it is possible to multiply the volumes by a common factor up to a maximum of 100 l for both of the parts of the mix .
a temperature close to 37c must be maintained when mixing the semen sample with the rg ; otherwise the mix will jellify .
the mix was gelified at 4c for 5 minutes and then incubated for 45 minutes at 37c .
the resulting color of the mix was compared with the color scheme and the corresponding os level was estimated .
alternatively a colorimeter can be used to measure the absorbance of wavelengths ranging from 530 nm to 630 nm . to obtain the best results ,
the samples were tested not after 60 minutes after ejaculation ; false positives may be obtained if longer delays are produced .
it is also very important to have a precise count of sperm concentration . in effect
, high sperm concentrations may produce high color intensities because of acceleration of os pressure by sperm collision followed by membrane damage .
samples were subsequently divided into two groups depending only on the os level detected with oxisperm : low os samples ( los ) including levels n1 and n2 and high os samples ( hos ) including levels n3 and n4 .
los samples have optimal / low levels of ros considered not able to damage cells .
hos samples have levels of ros so high that may cause pathological effects on sperms such as dna fragmentation .
this is a flow cytometric test that measures the ability of sperm dna to maintain its native double - stranded form after exposure to an acid environment , followed by staining with metachromatic fluorescent dye acridine orange ( ao ) ( 6 mg / ml sigma , st .
louis , mo , usa ) to differentiate single - stranded and double - stranded dna .
ao intercalates into native dna and fluoresces green when exposed to blue light and fluoresces red when associated with single - stranded ( abnormal ) dna .
the percentage of sperms with denatured dna was initially termed the percentage comp alpha t ( cells outside the main population ) and has recently changed to dna fragmentation index ( dfi ) .
the term alpha t is created from these fluorescence values , which uniquely identifies each sperm based on its own metachromatic emission characteristics .
scsa was carried out following the protocol described by evenson et al . with some modification of our laboratory .
flow cytometer beckman coulter fc 500 ( beckman coulter , pasadena , ca , usa ) was set up with excitation at 488 nm filters and dichroic filters to collect red ( 630 nm ) and green ( 515 to 530 nm ) fluorescence .
frozen samples were rapidly thawed in a 37c water bath until the last remnant of ice disappears and 100 l of sample was treated with 200 l of acid solution ( 0.08 n hcl , 0.15 m nacl , and 0.1% triton - x 100 , ph 1.2 ) for 30 seconds to induce sperm dna denaturation .
600 l of ao staining solution ( 1.2 ml , 6 g / ml ) was added to sperm suspension and incubated for 3 minutes .
the stained sample was placed on the flow cytometer and sample flow was started immediately .
duplicate measurements were performed taking the sample from the same thawed aliquot in order to have statistical considerations .
the percentage of sperms with denatured dna was expressed in terms of dfi using fcs4 express software that creates a scatter plot showing the ratio of green ( not fragmented ) and red ( fragmented ) sperms ( figure 2 ) .
a statistical threshold has been established to < 30% and 30% dfi for normal and high sperm dna fragmentation , respectively .
data were presented as median values ( interquartile ranges ) as sperm parameters were not normally distributed .
two - sample wilcoxon rank - sum ( mann - whitney ) test was used to test the relationship between os level and sperm dna damage ( % dfi ) and between os level and semen parameters including concentration of round cells .
a linear regression analysis was also done to address the change of dfi in accordance with the increase of os level .
table 1 shows p value of the data from seminal analysis of the samples analyzed in the study .
no statistically significant differences were found ( p < 0.05 ) when comparing the values obtained for each of the conventional semen analysis variables between the two groups .
the parameters evaluated in seminal analysis included sperm concentration ( p = 0.2297 ) , sperm motility ( p = 0.9462 ) , sperm viability ( p = 0.7312 ) , and the percentage of normal sperm forms ( p = 0.5513 ) .
the median of dfi and round cells concentration in the two groups is reported in table 2 . regarding the assessment of the integrity of sperm dna we evidenced a higher and statistically more significant dfi ( dfi 30% ) in the hos group as compared to the los group ( p = 0.0379 ) suggesting that superoxide anion unbalance is related to sperm dna fragmentation .
hos group shows a dfi median of 21.58% ( 6.8464.44 ) while the los group has a dfi median of 16.345% ( 4.9945.07 ) .
the linear regression analysis shows a statistically significant relationship between dfi and os level with a correlation coefficient value of 3.76 ( 95% ci : 0.52 , 6.99 ) . by evaluating the concentration of round cells in semen samples
, we observed high levels of os in the presence of high concentration of this kind of cells suggesting a strong correlation between round cells concentration > 1.5 10/ml in semen and high os levels ( p = 0.0084 ) ; this supports the knowledge that ros in human ejaculate originate mainly from leukocytes .
the median concentration of round cells in hos semen group is 0.8 10/ml ( 0.13.3 ) in opposition to 0.3 10/ml ( 0.12.5 ) in the los group .
os has been identified as one of the main causes of male infertility by causing sperm dysfunction .
os is a state related to increased cellular damage triggered oxygen and oxygen - derived free radicals known as ros .
usually , most clinicians do not test infertile man for os presence because available tests are expensive or difficult to perform as compared to a routine semen analysis . as antioxidant supplementation may improve sperm dna integrity and pregnancy outcome
, there is a clinical need to perform assays to identify os in order to put these results in relationship with sperm dna fragmentation . somehow , none of the parameters recommended by who ( sperm concentration , motility , and morphology ) are sufficient for male infertility determination . even though standard semen analysis continues to be the backbone of clinical evaluation of male infertility , who parameters only address few aspects of sperm quality and function and
this can explain why the discriminative power in relation to fertility is quite low and why high numbers of idiopathic infertility are observed [ 32 , 33 ] .
to the best of our knowledge , this study is the first to correlate seminal os using the semiquantitative test oxisperm with markers of sperm quality such as sperm dna fragmentation assessed by scsa . a significant positive correlation ( p < 0.05 ) between high semen os levels depending on superoxide anion unbalance and an increase in sperm dna fragmentation
was noted , in accordance with the well - established ros capacity to damage sperm dna .
some authors have reported a positive correlation between ros production and sperm dna fragmentation [ 4 , 35 ] . a positive correlation ( p < 0.05 ) between round cells concentration in semen major of 1.500.000/ml and growing in sperm dna fragmentation was also noted ; this is because round cells in semen include leukocytes and male germ cells that are considered the main endogenous sources of ros .
however , the relationship of high os levels and a decrease in normal semen parameters did not reach statistical significance ( p > 0.05 ) disagreeing with previous findings that spermatozoa from patients with abnormal sperm concentration , morphology , and motility show increased levels of dna damage .
this is probably due to the fact that all the patients involved in the study had andrological indication for the assessment of sperm dna fragmentation ; in this class of patients are included men with unexplained infertility that is diagnosed whenever routine testing methods including semen analysis fail to identify a reason for delay in achieving pregnancy .
other testing methods such as assessment of ros and dna fragmentation may reveal the actual cause of infertility in these cases . for these reasons
an accurate assessment of the seminal os levels should become an integral part of the andrology workup in order to assist clinicians in elucidating the fertility status and in establishing the optimal treatment .
this study provides support for oxisperm as a low cost and easy - to - perform assessment of sperm oxidative stress .
we acknowledge that our study is relatively small and needs to be replicated by others and compared with other methods for the assessment of sperm dna damage such as comet and tunel assays
. the future goal will be the collection of more data in order to assess if there is a primary role of seminal plasma in the oxidative stress process as seen from the results .
in conclusion , os is related to sperm dna fragmentation and high concentrations of round cells .
the evaluation of os and sperm dna damage would make a solid contribution to standard seminal analysis profile and become diagnostic tools for evaluation of male infertility especially of idiopathic origin which must be taken into consideration during andrological workup .
Output:
| oxidative stress ( os ) plays an essential role in male infertility aetiology by affecting sperm quality , function , and also the integrity of sperm dna .
the assessment of oxidative stress in semen may be an important tool to improve the evaluation of sperm reproductive capacity .
the purpose of this study was the evaluation of any possible relation between the unbalance of oxidative stress caused by superoxide anion in the ejaculate with the presence of sperm dna fragmentation and high concentration of round cells .
56 semen samples from males from couples suffering from infertility were evaluated according to world health organisation ( who ) 2010 guidelines .
oxidative stress levels from n1 ( low ) to n4 ( high ) were assessed in ejaculates using oxisperm ; dfi ( sperm dna fragmentation index ) as assessed by the scsa ( sperm chromatin structure assay ) was used for evaluation of sperm chromatin integrity .
our data show that high oxidative stress ( n3-n4 levels ) correlated positively with a dfi 30% ( p = 0.0379 ) and round cells 1.500.000/ml ( p = 0.0084 ) . in conclusion
, os increases sperm dna damage .
thus evaluation of semen os extent of sperm dna damage in infertile man could be useful to develop new therapeutic strategies and improve success of assisted reproduction
techniques ( art ) . |
PubmedSumm118799 | ***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 hyperstimulation syndrome ( ohss ) is a potentially life - threatening situation , and thus regarded to be the most serious complication of assisted reproduction treatment ( art ) .
it is characterized by the presence within the ovaries of multiple luteinized cysts , which leads to ovarian enlargement and secondary complications such as increased capillary permeability and fluid shift to the third space .
recent findings have identified vascular endothelial growth factor ( vegf ) as the major molecule responsible for increased capillary permeability .
the production of vegf in ovarian follicles increases during stimulation period , and results in a rapid increase in vascular permeability upon binding to type 2 vegf receptors .
although , cytokines and growth factors ( interleukins il-2 , il-6 , il-8 , il-10 , and il-18 ) , histamine , prolactin , prostaglandins and renin - angiotensin have been proposed as participants in ohss pathophysiology , the exact responsible factor is under debate .
standard treatments for ohss are generally conservative , and potentially life - threatening complications of ohss , which require costly long - term hospitalizations , render prophylactic measures a must . some approaches , which are based on the pathophysiology of ohss , are now applied for its prevention .
studies show a reduced incidence of ohss when recombinant luteinizing hormone ( rlh ) or a gonadotropin releasing hormone ( gnrh ) analogue is used to trigger the final steps of oocyte maturation .
prophylactic administration of cabergoline , a dopamine agonist , is associated with a significant reduction in the incidence of symptoms and signs of moderate to severe ohss .
its use is not associated with an inferior art outcome or obstetric / neonatal complications . in some cases ,
ovarian hypersensitivity to gonadotropins is the consequence of mutations in the follicular stimulating hormone ( fsh ) receptors .
genetic variations may cause different responses in various populations ; therefore , different responses to cabergoline may be detected .
the present study was conducted to determine the preventive effects of cabergoline on ohss , especially its severe forms , in patients referring to an iranian university hospital .
the study is a non - randomized clinical trial recruiting 75 patients , who had undergone assisted reproductive procedure and were at risk of ohss .
the study was conducted in the infertility department of shariati hospital , a teaching hospital affiliated to tehran university of medical sciences during 2006 - 2008 .
the project was approved by the ethics committee of the infertility department , and was initiated after obtaining written consents of the participants .
high risk patients were defined as young females , who had antral follicle counts of more than 15 , poly cystic ovaries on ultrasound scan and/or polycystic ovarian syndrome ( pcos ) , serum estradiol of more than 3500 pg / ml and/or multiple follicular recruitments in both ovaries during ultrasound monitoring in controlled ovarian hyperstimulation ( coh ) .
the inclusion criteria were an age of less than 33 years , high risk of developing ohss in the absence of taking antipsychotic medications , no known allergy to cabergoline or ergot alkaloids , and absence of hepatic dysfunction or hypertension .
polycystic ovarian syndrome was diagnosed according to rotterdam criteria . according to the rotterdam criteria , patients with two of the three characteristics including : 1 )
oligomenorrhea / amenorrhea , 2 ) clinical ( hirsutism ) finding of hyperandrogenism , or 3 ) polycystic ovaries on transvaginal sonography , were included in the study .
metabolic features of pcos patients were not of concern in this study ; therefore , insulin resistance and androgen index were not measured .
the oligomenorrhea / amenorrhea and polycystic appearance of ovaries were seen in more than two third of the pcos patients .
all of the participants underwent controlled ovarian hyperstimulation ( coh ) with gonadotropin / gnrh - agonist long protocol .
all of them received folic acid ( one mg / day ) before initiating the induction cycle , low dose oral contraceptive pills ( on the third of the previous cycle ) and doxycycline ( 100 mg twice a day ) for the first 10 days of the previous cycle .
long term desensitization protocol using subcutaneous gnrh agonist buserelin ( 500 g ) was started on the day 21 of the previous cycle .
after complete desensitization , ovarian stimulation using recombinant - fsh ( gonal f , serono , switzerland ) was commenced on day 3 of the next cycle at a daily dose 150 iu .
transvaginal ultrasound ( siemens , sonoline g20 ) was done every 3 - 5 days for the examination of follicular development , and serum estradiol levels were measured every 2 - 3 days using radioimmunoassay method . when at least two follicles with diameter of at least 17 mm were observed , final oocyte maturation was triggered with 10,000 iu human chorionic gonadotropin ( hcg , ferring , germany ) administered as a single intramuscular injection .
oocytes were collected 36 - 38 hours later under general anesthesia using transvaginal guided follicle aspiration .
after fertilization through intracytoplasmic sperm injection ( the routine art practiced at our center ) , three good quality embryos were transferred transcervically three days later .
luteal phase support was started the day after ovum pick up by the administration of progesterone suppository cyclogest ( actavis , uk ) at 800 mg / day .
the first group ( intervention or case group ) comprised 50 women treated with 1 mg of cabergoline ( dostinex,pharmacia italia s.p.a , italy ) every other day for eight days commencing on the day of ovum pick up .
the second group ( historical control group ) was comprised of 25 women , who were similar to the former group with respect to age as well as the number and quality of the retrieved oocytes , number and quality of the transferred embryos , embryonic stage at transfer , and the sperm quality .
the latter group did not receive cabergoline ; however , their ohss ( if occurred ) were managed conservatively according to our standard protocols after hospital admission .
all ohss patients were admitted to the hospital , and the diagnosis of ohss as well as its severity was performed according to a standard definition .
the standard classification categorizes the disease based on its severity to mild , moderate , and severe ohss . in mild ohss
, patients often report mild abdominal distention and soreness , nausea , vomiting , and ovarian enlargement between 5 to 12 cm .
severe diseases were diagnosed when there are clinical signs of tense ascites , hydrothorax , shortness of breath , hemoconcentration , hypercoagulability , or any complications of ohss such as renal failure , thromboembolism , or acute respiratory distress syndrome ( ards ) .
age , body mass index ( bmi ) , number of retrieved oocytes , number of metaphase ii oocytes , number and days of gonadotropin injections , estradiol level on the day of hcg administration were recorded .
chemical pregnancy was detected by the measurement of serum beta - hcg 14 days after the embryo transfer .
the existence of clinical pregnancy was confirmed using transvaginal ultrasound scan , which was scheduled two weeks later to detect the gestational sac of pregnancy .
abortion , early ohss ( mild , moderate , severe ) , cycle cancellation , frozen embryos and multifetal pregnancy were also recorded .
early ohss was defined as the onset of the syndrome during the first 9 days after hcg administration .
cycle cancellation was defined as receiving hcg and transvaginal guided follicle aspiration followed by fertilization through intracytoplasmic sperm injection , and freezing the resultant embryos for future transfers .
all of the patients were checked for any complaints or side effects of cabergoline , however , none of them reported any side effects .
baseline characteristics of patients in cabergoline - treated and control groups values are presented as meansd or frequency ( percent ) .
bmi ; body mass index , pcos ; polycystic ovarian syndrome , ohss ; ovarian hyperstimulation syndrome , fsh ; follicle stimulation hormone , lh ; leutinizing hormone quantitative data are presented as meansd .
quantitative and qualitative data were analyzed using student 's t test , and chi - square or fisher s exact test , respectively .
the data were analyzed using statistical package for social sciences ( spss version 14 , ( spss inc . ,
the mean age of the patients in the cabergoline - treated and control groups were 28.244.93 and 28.804.63 years , respectively.there was no significant ( p=0.637 ) difference between the ages of the two groups .
also , there was no significant difference between the two groups in terms of body mass index ( bmi ) , infertility duration , type and cause of infertility , serum levels of fsh and lh , pocs or history of previous ohss ( table 1 ) .
moreover , there was no significant difference between the method of art ( embryo transfer or rapid zygote intrafallopian transfer ) , serum estradiol levels on the day of hcg administration , fertilization rate , and the number of retrieved oocytes , mature oocytes , days of gonadotropin injections , pregnancy , or abortion of the two groups ( table 2 ) .
the incidence of ohss in cabergoline - treated group was significantly ( p=0.001 ) lower than that in the control group ( 12% vs. 36% ) .
embryo freezing ( surplus embryos ) was significantly ( p=0.001 ) lower in the latter group .
cycle cancellation in the cabergoline - treated group was significantly ( p=0.03 ) lower than that in the control group ( table 2 ) .
the incidences of mild , moderate and severe ohss in cabergoline - treated groups were 4% , 6% and 2% , and in the control group were 24% , 10% , 4% , respectively .
although the incidence of mild ohss was considerably lower in the cabergoline group , there was no significant difference between the incidence of moderate or severe ohss in cabergoline and control groups ( table 2 ) .
cabergoline , a dopamine agonist inhibiting vegfr-2 phosphorylation and signalling , effectively reduced the incidence of ohss and cycle cancellation without any adverse effects on pregnancy .
ovarian hyperstimulation syndrome , as a potentially life - threatening situation and the most serious complication of assisted reproduction treatment , is regarded as an iatrogenic complication which must be avoided , and in case of occurrence its severity must be reduced .
considering the physical and psychological consequences along with medical costs like hospitalization , every intervention to decrease vegf expression or antagonizing its effects would be valuable .
the ovary is the main source of cytokines and vegf , which are mediators that cause increased capillary permeability and ascites .
it has been suggested that parameters of ovarian activity during stimulation such as serum levels of estradiol and number of oocytes retrieved correlate closely with vegf gene expression .
animal studies have demonstrated that the expression of gene for tyrosine hydroxylase enzyme , which is the rate - limiting enzyme in dopamine synthesis , is significantly lower in rats with overstimulated ovaries .
high vegf expression and activity in ohss seem to be associated with reduced dopamine production .
moreover , serum levels of progestrone and rates of luteal apoptosis remained unchanged , suggesting the absence of a luteolytic effect of cabergoline .
the outcomes of ovarian stimulation in cabergoline - treated and control groups values are presented as meansd or frequency ( percent ) .
hcg ; human chorionic gonadotropin ; mii oocytes ; metaphase ii oocytes , art ; assisted reproduction treatment , ohss ; ovarian hyperstimulation syndrome .
zift ; zygote intrafallopian transfer beside inhibiting vegfr-2 phosphorylation and signalling , other theories have been suggested for the mechanism of action for cabergoline . in a study on hyperprolactinemic
pcos patients , a dopaminergic control of lh release and a support for the use of cabergoline in the management of these patients were shown .
cabergoline provided a better clinical control of ovarian response and consequently a reduction of the risk of ohss , and did not cause a decrease in pregnancy rate .
approximately half of the patients in each group ( cabergoline and control groups ) were those with pcos , and all of them had normal serum concentrations of prolactin .
the present study did not aim at evaluating the effect of cabergoline in hyperprolactinemic patients with pcos , and further studies are in need to shed light on the issue .
alvarez and colleagues , conducted a randomized , placebo - controlled double - blind clinical trial in oocyte donors at risk of ohss , and found that the incidence of moderate or severe ohss was significantly reduced in the cabergoline - treated group , without an adverse effect on ovarian function . in a retrospective analysis , alvarez and
colleagues showed that implantation and clinical pregnancy rates in women who received cabergoline for the prevention of ohss was similar to those in women matched for age , embryo quality , and semen parameters .
the present study showed that bmi , patients ' age , infertility duration , type and cause of infertility , serum levels of fsh and lh , pcos , or the history of previous ohss , estradiol level , pcos prevalence , and number of oocytes retrieved were similar between the two groups . in spite of the small sample size
, the present study has the advantages similarity of basal or background characteristics , cycle stimulation characteristics and minimal selection bias all of which make the study reliable for future practical and clinical purposes .
another study , compared early ohss , defined as the onset of the syndrome during the first nine days after hcg administration , and late ohss , characterized by the onset of the syndrome after 10 days after hcg administration .
cabergoline decreased the risk of early ohss significantly ( p<0.001 ) , but the risk of late onset ohss was not decreased .
there was no significant difference between the two groups in terms of pregnancy , implantation or miscarriage rates .
though not a randomized clinical trial , the findings of our study , namely decreasing the incidence of early ohss , are in agreement with those of such a report .
although the incidence of mild ohss decreased , the incidence of severe form of ohss did not change significantly . moreover , the effects of the cabergoline found in the present study are in agreement with those of previous publications .
the present study showed that cabergoline did reduce the incidence of ohss and the risk of hospitalization due to the lower occurrence of ohss .
these findings might be taken as evidence to suggest that cabergoline might be a valuable drug for the prevention and treatment of the abnormality . however , randomized controlled trials are in need to study the efficacy as well as safety of different doses and durations of cabergoline administration for both prophylactic and therapeutic purposes .
Output:
| type 2 receptors for vascular endothelial growth factor are believed to be involved in the pathophysiology of ovarian hyperstimulation syndrome ( ohss ) .
the objective of this study was to examine the preventive effects of cabergoline on ohss and its complications .
the study is a non randomized clinical trial conducted in 2006 - 2008 on 75 patients , which were at risk of ohss and underwent assisted reproductive techniques .
the diagnosis and severity of ohss were determined using standard criteria .
the study included an intervention and a control group .
the intervention group comprised of 50 women at risk of ohss , who were treated with cabergoline ( 1 mg every other day for 8 days ) commencing from the day of ovum pick up .
the control group comprised of 25 historical cases , which were similar to the case group .
the latter group did not receive cabergoline , and their ohss , if occurred , were managed conservatively after hospital admission . the rates of ohss , baseline characteristics , ovarian stimulation parameters , and pregnancy occurrence were compared . there was no significant difference between baseline characteristics or ovarian stimulation parameters form the two groups .
the incidence of ohss in the cabergoline - treated group , was significantly ( p=0.01 ) lower than that in the control group ( 12% vs 36% ) .
embryo freezing was significantly ( p=0.001 ) lower in the control group , but cycle cancellation was significantly ( 0.03 ) lower in the cabergoline group .
the findings of the study indicate that cabergoline reduces the incidence of ohss , and is not associated with adverse effects on pregnancy . |
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