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PubmedSumm6500 | ***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 previous issue of critical care , williams and colleagues provide an overview of the predominant causes of death in burned pediatric patients in order to develop new treatment avenues and future trajectories . over the past decades
there has been a significant decrease in mortality and morbidity in severe burns due to improved burn wound management and approaches in critical care [ 2 - 4 ] .
many advances have been made , not only concerning the pathophysiology of burns but also concerning burn management .
survival from severe burns is no longer the exception , but unfortunately death still occurs .
owing to the fact that the burn injury is multifaceted , the advances cross many injury processes .
these issues range from the management of the catabolic state to modern wound care .
one important aspect is that burn treatment has become more proactive , by searching out new technologies to solve old problems . now
the treatment approach is altering its focus on manipulating the course of a burn and its final outcome .
the survival rate is still of course the most important issue , but not the only issue .
the question of whether and to what degree the patient is able to enjoy a normal quality of life becomes more and more essential in how the outcome of the burn treatment is evaluated .
restoring function and esthetics are crucial in the difficult process of social reintegration and the return to a normal life .
great efforts were made in the past to develop epidermal and dermal replacements to overcome the problem of poor skin quality and scar contraction . in large and deep burns ,
the approach has changed to rapid excision and lesion - specific coverage of the burn wound , eliminating the burn as a source of complications .
rapid and effective wound coverage and closure are of utmost importance , but infection control and the preservation of active and passive motion are also essential for optimal recovery .
nonviable burn tissue is well recognized to be the driving force behind wound infection and burn wound sepsis .
williams and colleagues , who determined the predominant causes of death of burned children admitted between 1989 and 2009 , found that the dominant cause of death is sepsis ( 47% of all deaths ) .
moreover , they found an increase of deaths due to multidrug - resistant organisms from 42% to 86% over the past 20 years .
the aggressive use of antimicrobials has significantly improved survival , but has also led to an increased colonization of pathogens that have resistance to current therapies . in general , early removal and excision of the necrotic tissue with a consecutive rapid and effective closure of the burn wound has become the standard in the management of severe burns .
research has proven that application of antimicrobial dressings or early excision and grafting is the key to avoid burn wound infection and its extension to systemic infection [ 8 - 10 ] .
the timing and extent of surgery may vary , as well as the method of closing , between different burn centers , but the principal concept is almost the same . based on the findings of williams and colleagues , respiratory failure accounted for 29% of all deaths - 83% of these
although the methods used for the management of acute respiratory distress syndrome have changed dramatically over the past 20 years , mortality has remained almost the same .
moreover , it seems that there is a need for further studies or for a revisit to the manner in which studies are conducted and their results are implemented in the real world .
resuscitation is the major component of initial burn care and must be managed to restore and preserve organ function .
prevention of inadequate perfusion , due to burn fluid loss , remains the top priority for initial management .
advances in fluid management have led to a marked decrease in fatal burn shock and its related complications .
the obvious challenge concerning resuscitation is to provide enough fluid to maintain perfusion without causing overload . without effective and rapid intervention
, hypovolemia will develop . a delay in fluid resuscitation beyond 2 hours of the burn injury complicates resuscitation and increases mortality .
the consequences of excessive resuscitation and fluid overload are as deleterious as those of under - resuscitation : pulmonary edema , myocardial edema , conversion of superficial into deep burns , the need for fasciotomies and abdominal compartment syndrome .
a recent approach has led to conversion of a formula - driven process to a more critical care approach using more physiologic endpoints such as urinary output and other measurements , so the trend in burn resuscitation is shifting the focus from fluid formulas to adequate endpoint monitoring , edema control and adjuvant therapies . on some level
, a lot of burn deaths may be preventable with better airway management and more precise and adequate volume management .
sepsis due to multidrug - resistant organisms , however , will continue to impede efforts to increase survival .
we have to develop strategies to fight these organisms that go beyond the surgical and clinical techniques that are already implemented .
moreover there will be a need for further studies that are facing the problems concerning respiratory and multiorgan failure .
Output:
| many advances have been made in the understanding and treatment of burns .
advances in burn surgery and critical care have decreased mortality and morbidity . survival from severe burns
is no longer the exception , but unfortunately death still occurs .
williams and colleagues have determined in their recent paper the predominant causes of death in order to develop new treatment avenues and future trajectories suitable to increase survival and overall outcome .
a lot of burn deaths may be preventable with better airway management and a more precise and adequate volume management , but the leading cause of death in patients suffering from severe burns , which has to be faced , is sepsis .
sepsis due to multidrug - resistant organisms will continue to impede efforts to increase survival , and new strategies that go beyond the surgical and clinical techniques , which are already implemented , have to be developed in order to fight these organisms and their related complications . |
PubmedSumm6501 | ***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: global expansion of dengue virus ( denv ) has lead to endemicity in several regions , including central and south america.1,2 each year , returning travelers from these and other locations introduce the virus into a largely naive population in the united states.3 with the exception of self - limited chains of local transmission in florida , there has yet to be a sustained outbreak in the us.48 however , the threat remains as global travel , trade , and transport increase.1 to establish local transmission when virus is introduced , competent mosquito vectors need to be present . the primary vector , aedes aegypti , is present year - round throughout the southern us , including seasonally in subtropical and more temperate areas.9 vector competence is the ability of a mosquito population to become infected with and ultimately transmit an arbovirus . the vector competence of denv in a. aegypti is known to be affected by both intrinsic and extrinsic factors , such as viral strain and temperature / humidity , respectively.1013 the influence of temperature on vector competence is multifaceted and influences the rate of dissemination through the mosquito to the salivary glands , as well as the lifespan of the mosquito.14 the extrinsic incubation period ( eip ) is an important epidemiological measure and is defined as the time it takes for a virus to disseminate through a mosquito from the midgut where virus enters the mosquito after blood feeding to the salivary glands where it is then expectorated upon subsequent feeding .
the eip , while often reported as an average , discrete value , is a continuous process and is therefore tied to the mortality rate of a mosquito . if , for example , a specific strain of virus takes seven days ( on average ) to disseminate through a mosquito vector , the lifespan of that mosquito will determine how many days of infectiousness results from exposure ( fig .
1 ) . in a mosquito that is known to have multiple blood meals per gonotrophic cycle , such as a. aegypti ,
this is especially relevant as it results in a much higher potential for transmission through an increased rate of human contact .
temperature , as a driver of vector competence , eip , and mortality , is a critical environmental factor when considering transmission dynamics of arboviruses .
in addition , previous studies have observed altered protein expression in salivary glands of mosquitoes with disseminated denv2 infections , including metabolic proteins,15 which may indicate that there is some alteration in fitness to mosquitoes with a disseminated infection . to that end , we explored the interaction among temperature , infection / dissemination status , and mosquito mortality .
specifically , we investigated whether mosquitoes had different likelihoods of survival depending on their infection and/or dissemination status and the temperature to which they were exposed during the eip .
a. aegypti mosquitoes ( rockefeller strain ) from the louisiana state university ( lsu ) colony were reared at a constant temperature of 28 c with approximately 85% humidity and a 16:8 light / dark cycle.16 pupae were separated into batches of 100 per carton and allowed to emerge .
three to five days postemergence , cartons of adult mosquitoes were exposed to a blood meal containing a 1:2 mixture of either uninfected cell culture supernatant and blood or infected cell culture and blood .
the virus used was denv2 , strain 1232 was originally isolated from a patient in indonesia.17 for each experimental group , an environmental chamber was programmed to a constant extrinsic incubation temperature ( eit ) of 26 c , 28 c , or 30 c with all other parameters as above .
six cartons each of unexposed mosquitoes and denv2 exposed mosquitoes were placed in an environmental chamber and incubated at constant temperature for the duration of the eip until the study concluded at 22 days postexposure .
total sample sizes per group are listed in table 1 . each day , mosquitoes that had died within the previous 24 hours were removed from the carton and the day postexposure was recorded .
each mosquito was processed for the detection of denv2 rna in the bodies and legs , as infected legs are an indication of a disseminated infection and has previously been used as a proxy for vector competence.18,19 mosquitoes were grouped as follows : unexposed referring to mosquitoes receiving a blood meal with no virus present ; infected referring to mosquitoes that were exposed to denv2 and developed an infection in the abdomens at the time of death ; and disseminated referring to mosquitoes that were exposed and developed a disseminated infection in the legs.16 at the end of the study ( 22 days postexposure ) , mosquitoes that were still alive were killed via flash freezing and processed as described in ref . 20 . for the purposes of the survival analysis , these mosquitoes were coded in the dataset as right - censored observations , as they did not experience the event ( death ) during the study period .
a kaplan meier nonparametric survival analysis was performed using proc lifetest in sas ( version 9.4 ) to determine whether time to death among groups was significantly different .
we set the type i error rate at = 0.05 for pairwise comparisons , and applied a bonferroni adjustment to the type i error rate to account for multiple comparisons wherever appropriate .
we first analyzed only the unexposed group to determine whether there was a significant effect of temperature on mosquito survival in the absence of infection .
this required a bonferroni adjustment to the significance level of /3 = 0.0167 to account for three pairwise comparisons across three temperatures .
next , we performed pairwise comparisons of unexposed mosquitoes to infected mosquitoes at each temperature , followed by pairwise comparisons of unexposed mosquitoes to mosquitoes that developed a disseminated infection at each temperature . finally , we compared survival of infected mosquitoes at each temperature and that of disseminated mosquitoes at each temperature .
these two tests also required the same bonferroni adjustment to the significance level as described above .
there was no significant effect of temperature when we compared mortality among mosquitoes in the unexposed group ( p < 0.05 ) .
survival curves are depicted in figure 2 , and the average times to death for this and the other groups are given in table 2 .
there was also no significant difference when time to death was compared between unexposed mosquitoes and either ( 1 ) infected mosquitoes or ( 2 ) disseminated mosquitoes at 26 c and 28 c . at 30 c , there was a significant difference between the survival of unexposed mosquitoes and infected mosquitoes , with average times to death of 15.09 and 8.60 days ( post exposure ) , respectively ( fig .
when we then compared unexposed mosquitoes to mosquitoes that had developed a disseminated infection , we also observed a shorter lifespan in those mosquitoes with disseminated denv2 infections at 30 c by about half a day ( fig .
3b ) . though these differences are small for both infected and disseminated comparisons with unexposed mosquitoes , they are significant ( p - values = 0.0078 and 0.0219 , respectively ) .
we then compared differences in survival for infected individuals only across the three temperatures and found a significant difference among the three ( p - value = 0.002 , adjusted = 0.0167 ) .
interestingly , the difference was observed between those kept at 26 c and 30 c ( pairwise comparison p - value = 0.0004 , adjusted = 0.0167 ) , but no difference was observed between the 28 c and 30 c or 26 c and 28 c ( fig .
the same pattern was observed when we analyzed the survival of mosquitoes with disseminated infections across the three temperatures ( p - value = 0.0029 , adjusted = 0.0167 ) , with significance only between the 26 c and 30 c temperatures ( pairwise p - value = 0.0014 , adjusted = 0.0167 ; fig .
vector competence is an important factor in the emergence , expansion , and persistence of arboviruses , but this static quantity does not often capture the whole picture.16 quantification and assessment of relative differences in vector competence is incomplete without accounting for variation in temporality , which is in turn affected by factors such as temperature.21 as the global temperature trends toward warming , there will likely be two ( very general ) impacts on tropical mosquito vectors .
first , indigenous species may experience prolonged exposure to higher temperatures as well as exposure to more extreme temperatures .
second , the geographical range of these vectors will expand into more temperate regions , albeit only seasonally in some areas.22 our results suggest that infection and dissemination may alter the long - term mortality rate of mosquitoes infected with denv2 at higher temperatures , though others have shown and our data do not dispute that the short - term mortality of mosquitoes was not affected by infection and our result ( table 2).23 our results indicate that there is a fitness cost associated with infection and dissemination at higher temperatures .
the additional finding that , at a lower eit , the lifespan of a mosquito is longer coupled by the fact that viral dissemination is slower at lower temperatures may also suggest a trade - off of viral efficiency and potential fitness cost ( ie , differential mortality ) for mosquitoes . while temperature is a known effector of the rate of arboviral dissemination ,
our study demonstrates the nonlinearity of the relationship between mortality and virus replication.14,2426 however , the differences observed in our study still do not offer a clear interpretation of this interaction as driven by changes in eit .
thus , the interplay between these two processes should be further characterized , as our data suggest different likelihoods of survival depending on infection and/or dissemination of the vectors and the temperature to which they are exposed during eit .
this study offers insight into the combined processes of mortality and infection dynamics within the mosquito .
such information can not only offer insights into altered transmission patterns due to climate change and warming but also lead to more specific parameter development for mathematical models that look to predict expansion or emergence of future public health threats , such as dengue .
Output:
| the extrinsic incubation period is a critical component in the assessment of arboviral transmission potential .
it defines the time it takes for a mosquito to become infectious following exposure to an arbovirus . since this is a temporal process , the lifespan of a mosquito is intimately tied to the extrinsic incubation period and thus transmission potential of these viruses .
temperature is a known effector of both vector competence ( the ability of a vector to transmit a pathogen ) and mosquito mortality , but the interaction among temperature , vector competence , and mosquito mortality is not well characterized .
herein , we investigate this interaction for dengue virus , serotype 2 , and its primary vector aedes aegypti where we found that at 30 c , infection and/or dissemination shortened the average lifespan of the mosquito and that when considering only mosquitoes with a disseminated infection , those incubated at 26 c lived significantly longer . |
PubmedSumm6502 | ***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 peritoneal cavity is opened , in whatever type of surgery , bowel obstruction may develop due to bands or adhesions .
the release of such adhesions results in serosal injury to the bowel and is a potential threat for re - adhesion and obstruction .
use of intraluminal tube stenting of the bowel after release of adhesions precludes recurrent small bowel obstructions .
over a period of 14 years , six children needed intraluminal stenting of the bowel to prevent recurrent obstruction .
four of these children needed two surgeries in the immediate postoperative period . in two other children who developed adhesive obstruction in the postoperative period ,
release of dense adhesions resulted in raw areas in peritoneum and the bowel , and stenting of the bowel was done to prevent re - adhesion .
of the six children , three were following surgery for hirschsprung 's disease , while the other three were due to intestinal duplication , meckel 's diverticulum and meconium ileus . in the absence of the availability of pediatric size baker 's type of tube which has a bulb distally for easy passage across the bowel , we used two 10f ryle 's tubes of 100 cm each , stitched together and guided through a jejunostomy in two children .
the tubes were stitched with 2/0 silk twice and tested to see that it does not break before passing across the bowel .
the tubes were guided upward through the base of the appendix after appendicectomy to the jejunum . in children with gross distension of bowel
, a 10f ryle 's tube with side holes was inserted through a purse string in upper jejunum and the bowel was decompressed by suction , and then the second tube was stitched to the first and guided toward the cecum .
similar procedure was done when the tubes were guided from the base of the appendix after appendicectomy .
the stenting through the base of the appendix after appendicectomy and subsequent fixation of the tube through right iliac fossa results in natural lie of the bowel .
the four children in whom the above method was done went home without any problem .
the bowel is returned in anatomical way ; the adhesions which are certain to recur are thereby fixed with the bowel in a non - obstructing position .
the child can be fed orally after 34 days when the bowel function returns to normal .
stenting through jejunostomy was preferred when there was gross distension of proximal bowel for easy decompression and the base of the appendix in the rest [ figure 1 ] .
two 100 cm ryle 's tubes joined together and passed from the base of appendix to jejunum
postoperative intraperitoneal adhesions , or bands , resulting from any type of abdominal surgery are the main cause of adhesive postoperative small bowel obstructions , which represent a lifelong issue . after successful relief of obstruction in dense and extensive adhesions
, there is no proven method to prevent formation of further adhesions postoperatively , and a small number of patients are plagued by recurrent obstruction . the need for repeated laparotomy in such patients can pose great technical difficulties for the surgeon .
various methods of prevention of recurrence of adhesive obstructions were tried in adult patients earlier .
plication of the small intestine is often performed in situations suggesting an increased risk of subsequent adhesive obstruction .
this can be accomplished by the external suture methods of noble and modified technique of transmesenteric plication described by childs and phillips .
the major objections to noble 's plication are the duration of the operation and the incidence of postoperative complications .
hyaluronate carboxymethylcellulose preparations have been shown to reduce the extent of adhesions in pediatric patients .
however , in adult patients , several other studies have shown that the use of hyaluronate carboxymethylcellulose agents is associated with a significantly higher incidence of intra - abdominal abscesses and anastomotic leaks .
again , accepting that adhesions will form , intestinal intubation relies on the intrinsic stiffness of the intraluminal tube to permit adhesion formation in a favorable position and to avoid kinking of the bowel whilst adhesions form .
intraluminal stenting of the small bowel after adhesiolysis was originally described by white in 1956 as a possible way to maintain small bowel patency while fresh adhesions form , thereby reducing the risk of subsequent adhesional obstruction .
it was popularized by baker who introduced a long intestinal tube with a foley 's type of bulb distally to facilitate smooth introduction of the tube through jejunostomy .
he emphasised on the need to decompress the distended bowel thoroughly at the time of surgical release of the obstructing adhesion .
complications associated with the jejunal route of stent insertion are infection or prolonged drainage from the jejunostomy site following tube removal , or obstruction at the jejunostomy site and intussusception.[810 ] of the six cases who had intestinal tubing , four children had recurrent adhesive obstruction in the immediate postoperative period . in two children ,
the adhesions were so dense in the first instance and the intestinal stenting was done to prevent further small bowel obstruction
. technically it would be easy to pass the tube across the bowel if there is a foley type of bulb in the tube , and in its absence , ryle 's tube was used in our cases . in the above series ,
there had been no complication at the tube site or in its removal though there is a report that the tube got kinked and there was difficulty in its extraction .
the spillover of the intestinal contents , with its attendant complication of intra - abdominal abscess or wound infection in grossly distended bowel is prevented during jejunostomy or the retrograde passage of tube by passing initially a 10f ryle 's tube with multiple holes and the bowel is decompressed by suction and the second tube attached to it later .
baker returned the bowel with the tube in situ in an orderly manner simulating a plication and wrote that he has only incomplete evidence in some cases that the orderly intestinal pattern is permanently maintained .
we returned the bowel into abdomen in the anatomical way as the return of bowel in the plicated manner in small children was technically difficult .
intestinal intubation in the treatment of patients with recurrent adhesive small bowel obstruction has been documented in adult patients .
the present study , though with a small number of patients , shows its utility in preventing recurrent small bowel obstruction where initial surgery has produced adhesive obstruction .
it is unlikely to be of use in the treatment of localized adhesions or situations where formation of generalized adhesions is uncommon .
Output:
| aim : six children with adhesive obstruction in the postoperative period were treated with stenting the small bowel with long intestinal tube.materials and methods : in two children the stenting was done through jejunostomy , and in the other four through the base of appendix.results:during a follow - up period of 2 - 14 years , there had been no recurrence.conclusions:use of an intraluminal tube stent in preventing recurrent small bowel obstruction due to adhesions is safe and effective when used on appropriately selected patients . |
PubmedSumm6503 | ***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 spine can be involved in most inflammatory disorders encompassing rheumatoid arthritis ( ra ) , seronegative spondyloarthritides ( spa ) , juvenile arthritides and less frequent disorders such as pustulotic arthro - osteitis and sapho ( synovitis , acne , pustulosis , hyperostosis , osteitis ) syndrome . during the last decade
the diagnostic use of magnetic resonance imaging ( mri ) and computed tomography ( ct ) has increased considerably , although radiography is still the recommended initial examination .
it is therefore important to know the characteristic radiographic findings in arthritides in addition to the advantages of supplementary mri and ct .
this review will focus on the different imaging features and be concentrated on the most frequent inflammatory spinal changes seen in ra and spa , respectively .
involvement in ra is usually located in the cervical spine where erosive changes are predominantly seen in the atlanto - axial region . inflamed and thickened synovium ( pannus )
can occur around the odontoid process ( dens ) and cause bone erosion and destruction of surrounding ligaments , most seriously if the posterior transverse ligament is involved .
laxity or rupture of the transverse ligament causes instability with a potential risk of spinal cord injury .
cervical ra involvement is a progressive , serious condition with reduced lifetime expectancy , and its diagnosis is therefore important [ 2 , 3 ] .
it should always include a lateral view in a flexed position compared with a neutral position in addition to special views of the dens area to detect any lesions and/or instability ( fig . 1 )
. a supplementary lateral view during extension can be useful to assess reducibility of atlanto - axial subluxation possibly limited by pannus tissue between the anterior arc of the atlas and dens .
( a ) lateral radiographs in neutral position and ( b ) during flexion in addition to ( c ) lateral and ( d ) anterior - posterior ( ap ) open - mouth view of the atlanto - axial region ( 45-year - old woman ) .
the flexion view ( b ) shows abnormal distance ( > 3 mm ) between the posterior aspect of the anterior arc of the atlas and the anterior aspect of the dens ( black line ) .
note that the spino - laminar line of the atlas ( arrow ) does not align with that of the other vertebrae , confirming the presence of anterior subluxation , but there is no stenosis of the atlanto - axial canal ; the posterior atlanto - dental interval ( white line ) is > 14 mm .
the open - mouth view ( d ) shows erosion at the base of the dens ( arrow ) .
( a ) and ( b ) show concomitant disc degenerative changes at the c4c6 level standard radiography of the cervical spine in rheumatoid arthritis ( ra ) .
( a ) lateral radiographs in neutral position and ( b ) during flexion in addition to ( c ) lateral and ( d ) anterior - posterior ( ap ) open - mouth view of the atlanto - axial region ( 45-year - old woman ) .
the flexion view ( b ) shows abnormal distance ( > 3 mm ) between the posterior aspect of the anterior arc of the atlas and the anterior aspect of the dens ( black line ) .
note that the spino - laminar line of the atlas ( arrow ) does not align with that of the other vertebrae , confirming the presence of anterior subluxation , but there is no stenosis of the atlanto - axial canal ; the posterior atlanto - dental interval ( white line ) is > 14 mm .
the open - mouth view ( d ) shows erosion at the base of the dens ( arrow ) .
( a ) and ( b ) show concomitant disc degenerative changes at the c4c6 level anterior atlanto - axial subluxation is the most frequent form of ra instability in the occipito - atlanto - axial region , but lateral , rotatory and vertical subluxation can also occur .
distance between the posterior aspect of the anterior arc of the atlas and the anterior aspect of the dens exceeding 3 mm in a neutral position and/or during flexion ( fig . 1 ) .
it may cause stenosis of the atlanto - axial canal presenting as a posterior atlanto - dental interval < 14 mm ( fig . 1 ) .
displacement of the lateral masses of the atlas more than 2 mm in relation to that of the axis and asymmetry of the lateral masses relative to the dens , respectively ( fig . 2 ) .
rotatory and lateral subluxation is diagnosed on open - mouth anterior - posterior ( ap ) radiographs .
anterior subluxation often coexists because of the close anatomical relation between the atlas and the axis .
there is narrowing of the atlanto - axial joints with superficial erosions ( black arrow ) and lateral displacement of the axis with respect to the lateral masses of the atlas ( white arrow ) ; in addition signs indicating rotatory displacement with asymmetry of the distance between the dens and the lateral masses of the atlas lateral and rotatory atlanto - axial subluxation . ap open - mouth view in a 53-year - old man with ra .
there is narrowing of the atlanto - axial joints with superficial erosions ( black arrow ) and lateral displacement of the axis with respect to the lateral masses of the atlas ( white arrow ) ; in addition signs indicating rotatory displacement with asymmetry of the distance between the dens and the lateral masses of the atlas the anterior arc of the atlas moves over the odontoid process .
. is also referred to as atlanto - axial impaction , basilar invagination or cranial setting , and is defined as migration of the odontoid tip proximal to mcrae s line corresponding to the occipital foramen .
this line can be difficult to define on radiographs , and vertical subluxation has therefore also been defined by several other methods .
migration of the tip of the odontoid process > 4.5 mm above mcgregor s line ( between the postero - superior aspect of the hard palate and the most caudal point of the occipital curve ) indicates vertical subluxation ( fig . 3 ) .
( a ) lateral normal radiograph in neutral position showing the location of mcgregor s line ( black ) between the postero - superior aspect of the hard palate and the most caudal point of the occipital curve . migration of the tip of the dens > 4.5 mm above mcgregor s line indicates vertical subluxation . the distance indicated by the white line between mcgregor s line and the midpoint of the inferior margin of the body of axis
is used to evaluate vertical subluxation according to redlund - johnell and pettersson s method .
a distance less than 34 mm in men and 29 mm in women indicates vertical subluxation .
( b ) sagittal ct reconstruction of a normal cervical spine showing the location of mcrae s line corresponding to the occipital foramen and the division of the axis into three equal portions used by clark s method for diagnosing vertical subluxation .
if the anterior arc of the atlas is in level with the middle or caudal third of the axis there is slight and pronounced vertical subluxation , respectively .
( c ) ranawat s method includes determination of the distance between the centre of the second cervical pedicle and the transverse axis of the atlas .
a distance less than 15 mm in males and 13 mm in females indicates vertical subluxation vertical atlanto - axial subluxation , measurement methods . ( a ) lateral normal radiograph in neutral position showing the location of mcgregor s line ( black ) between the postero - superior aspect of the hard palate and the most caudal point of the occipital curve .
migration of the tip of the dens > 4.5 mm above mcgregor s line indicates vertical subluxation . the distance indicated by the white line between mcgregor s line and the midpoint of the inferior margin of the body of axis
is used to evaluate vertical subluxation according to redlund - johnell and pettersson s method .
a distance less than 34 mm in men and 29 mm in women indicates vertical subluxation .
( b ) sagittal ct reconstruction of a normal cervical spine showing the location of mcrae s line corresponding to the occipital foramen and the division of the axis into three equal portions used by clark s method for diagnosing vertical subluxation .
if the anterior arc of the atlas is in level with the middle or caudal third of the axis there is slight and pronounced vertical subluxation , respectively .
( c ) ranawat s method includes determination of the distance between the centre of the second cervical pedicle and the transverse axis of the atlas .
a distance less than 15 mm in males and 13 mm in females indicates vertical subluxation the occurrence of dens erosion can , however , make this measurement difficult to obtain .
the redlund - johnell method is therefore based on the minimum distance between mcgregor s line and the midpoint of the inferior margin of the body of the axis on a lateral radiograph in a neutral position ( fig .
( described in ) includes assessment of the location of the atlas by dividing the axis into three equal portions on a lateral radiograph .
location of the anterior arc of the atlas in level with the middle or caudal third of the axis indicates vertical subluxation ( fig .
have proposed using the distance between the centre of the second cervical pedicle and the transverse axis of the atlas at the odontoid process ( fig .
3 ) . to obtain the diagnosis of vertical subluxation a combination of the redlund - johnell , clark and ranawat methods has been recommended ( described in ) .
if any of these methods suggests vertical subluxation mri should be performed to visualise the spinal cord ( fig .
4 ) . using this combination of methods vertical subluxation will be missed in only 6% of patients .
it is mandatory to diagnose vertical subluxation ; this can be fatal because of the proximity of the dens to the medulla oblongata and the proximal portion of the spinal cord .
risk of cord compression / injury occurs , especially in patients with flexion instability accompanied by erosive changes in the atlanto - axial and/or atlanto - occipital joints , causing the vertical subluxation with protrusion of the dens into the occipital foramen ( figs .
( a ) lateral radiograph with mcgregor s line ( black line ; 61-year - old man with ra ) .
the tip of the dens is difficult to define , but measurement according to redlund - johnell s method ( white line ) results in a distance of 27 mm , which is below the normal limit . in accordance with this ,
the anterior arc of the atlas is level with the middle third of the axis .
( b ) ranawat s method , the distance between the centre of the second cervical pedicle and the transverse axis of the atlas is below the normal limit ( 9 mm ) .
supplementary mri , ( c ) sagittal stir and ( d ) t1-weighted images show erosion of the dens and protrusion of the tip into the occipital foramen causing narrowing of the spinal canal to 9 mm , but persistence of cerebrospinal fluid around the cord .
there is a 9-mm - thick mass of pannus tissue between the dens and anterior arc ( black line ) exhibiting small areas with high signal intensity on the stir image ( arrow ) compatible with slight activity , but signal void fibrous pannus tissue predominatesfig .
mri of the cervical spine in a 69-year - old woman with advanced peripheral ra , neck pain and clinical signs of myelopathy .
( a ) sagittal stir , ( b ) sagittal t1 and ( c ) axial t2 fat - saturated ( fs ) images show erosion of the dens and protrusion of the tip into the occipital foramen causing compression of the spinal cord , which exhibits irregular signal intensity ( white arrows ) .
the osseous spinal canal has a width of approximately 7 mm ( black line ) .
there is heterogeneous signal intensity pannus surrounding the dens compatible with a mixture of fibrotic and oedematous pannus tissue ( black arrows ) in the widened space between the dens and the anterior arc of the atlas vertical subluxation .
( a ) lateral radiograph with mcgregor s line ( black line ; 61-year - old man with ra ) .
the tip of the dens is difficult to define , but measurement according to redlund - johnell s method ( white line ) results in a distance of 27 mm , which is below the normal limit . in accordance with this ,
the anterior arc of the atlas is level with the middle third of the axis .
( b ) ranawat s method , the distance between the centre of the second cervical pedicle and the transverse axis of the atlas is below the normal limit ( 9 mm ) .
supplementary mri , ( c ) sagittal stir and ( d ) t1-weighted images show erosion of the dens and protrusion of the tip into the occipital foramen causing narrowing of the spinal canal to 9 mm , but persistence of cerebrospinal fluid around the cord .
there is a 9-mm - thick mass of pannus tissue between the dens and anterior arc ( black line ) exhibiting small areas with high signal intensity on the stir image ( arrow ) compatible with slight activity , but signal void fibrous pannus tissue predominates vertical subluxation with spinal cord compression .
mri of the cervical spine in a 69-year - old woman with advanced peripheral ra , neck pain and clinical signs of myelopathy .
( a ) sagittal stir , ( b ) sagittal t1 and ( c ) axial t2 fat - saturated ( fs ) images show erosion of the dens and protrusion of the tip into the occipital foramen causing compression of the spinal cord , which exhibits irregular signal intensity ( white arrows ) .
the osseous spinal canal has a width of approximately 7 mm ( black line ) .
there is heterogeneous signal intensity pannus surrounding the dens compatible with a mixture of fibrotic and oedematous pannus tissue ( black arrows ) in the widened space between the dens and the anterior arc of the atlas also occur in the form of arthritis of the apophyseal and/or uncovertebral joints , appearing as narrowing and superficial erosions by radiography .
it can cause instability in the c2-th1 region , which is mainly seen in patients with severe chronic peripheral arthritis .
it is defined as at least 3 mm forward slippage of a vertebra relative to the underlying vertebra by radiography including a flexion view ( fig .
changes are particularly characteristic at the c34 and c45 level , but multiple levels may be involved , producing a typical stepladder appearance on lateral radiographs .
the condition is serious if the subaxial sagittal spinal canal diameter is < 14 mm , implying a possibility of spinal cord compression .
the instability may progress over time , especially if the c1c2 region is stabilised surgically ( fig .
( a ) flexion view in a 64-year - old woman with advanced peripheral ra showing anterior atlanto - axial instability as well as subaxial instability at multiple levels .
( b ) flexion view 2 years later after surgical stabilisation of the atlanto - axial region demonstrates progression of the subaxial instability , especially between c3 and c4 ( white arrow ) .
there is a characteristic stepladder appearance , which also occurred on the initial radiographs ( a ) , but is less pronounced subaxial instability .
( a ) flexion view in a 64-year - old woman with advanced peripheral ra showing anterior atlanto - axial instability as well as subaxial instability at multiple levels .
( b ) flexion view 2 years later after surgical stabilisation of the atlanto - axial region demonstrates progression of the subaxial instability , especially between c3 and c4 ( white arrow ) .
there is a characteristic stepladder appearance , which also occurred on the initial radiographs ( a ) , but is less pronounced discitis - like changes and spinous process erosion may also be detected by radiography in ra , but are relatively rare , whereas concomitant degenerative changes occur occasionally ( fig . 1 ) .
cross - sectional imaging in the form of ct and mri eliminates overprojecting structures and can improve the detection of ra changes .
osseous changes ( erosions , etc . ) can be clearly delineated by ct . additionally , mri visualises soft tissue structures ( pannus ; spinal cord , etc . ) , signs of disease activity and sequelae of inflammation in the form of fibrous pannus .
these advantages of ct and mri in patients with atlanto - axial involvement are illustrated in figs .
7 and 8 , including the possibility of detecting signs of arthritis by mri before the occurrence of erosive changes ( fig .
7advantages of ct and mri . ( a ) supplementary ct and ( b - f ) mri of the patient shown in fig . 1 .
ct demonstrates erosion not only at the base of the dens , but also at the tip and at the atlanto - axial and atlanto - occipital joints , which are difficult to visualise by radiography .
mri , ( b ) sagittal stir and ( c ) sagittal t1 of the entire cervical spine and post - contrast t1fs images of the atlanto - axial region , ( d ) sagittal , ( e ) coronal and ( f ) axial .
oedematous voluminous pannus surrounding the dens is seen on the stir and t1 images ( black arrows ) in addition to c4/5 and c5/6 disc degeneration with posterior protrusion of the disc at c4/5 .
the post - contrast t1fs images confirm the presence of vascularised enhancing pannus around the dens ( white arrows ) and demonstrate improved anatomical delineation compared with the stir image .
mri in a 41-year - old woman with peripheral erosive ra and neck pain , but normal cervical radiography .
( a ) post - contrast axial and ( b ) coronal tifs images show signs of active arthritis with synovial contrast enhancement at the left atlanto - axial joint in addition to enhancing pannus tissue at the left side of the dens ( white arrows ) .
there is also a subchondral enhancing area in the axis ( black arrow ) compatible with a pre - erosive lesion advantages of ct and mri .
( a ) supplementary ct and ( b - f ) mri of the patient shown in fig
ct demonstrates erosion not only at the base of the dens , but also at the tip and at the atlanto - axial and atlanto - occipital joints , which are difficult to visualise by radiography .
mri , ( b ) sagittal stir and ( c ) sagittal t1 of the entire cervical spine and post - contrast t1fs images of the atlanto - axial region , ( d ) sagittal , ( e ) coronal and ( f ) axial .
oedematous voluminous pannus surrounding the dens is seen on the stir and t1 images ( black arrows ) in addition to c4/5 and c5/6 disc degeneration with posterior protrusion of the disc at c4/5 .
the post - contrast t1fs images confirm the presence of vascularised enhancing pannus around the dens ( white arrows ) and demonstrate improved anatomical delineation compared with the stir image .
mri in a 41-year - old woman with peripheral erosive ra and neck pain , but normal cervical radiography .
( a ) post - contrast axial and ( b ) coronal tifs images show signs of active arthritis with synovial contrast enhancement at the left atlanto - axial joint in addition to enhancing pannus tissue at the left side of the dens ( white arrows ) .
there is also a subchondral enhancing area in the axis ( black arrow ) compatible with a pre - erosive lesion a diagnostic strategy according to younes et al .
this includes an indication for radiography in all ra patients with disease duration > 2 years as cervical involvement may occur in over 70% of patients and has been reported to be asymptomatic in 17% of ra patients .
it is recommended to monitor patients with manifest peripheral erosions accompanied by rf ( rheumatoid factor ) and anticcp ( antibodies to cyclic citrullinated peptide ) positivity every second year and patients with few peripheral erosions and rf negativity at 5-year intervals .
mri is indicated in patients with neurological deficit , radiographic instability , vertical subluxation and subaxial stenosis [ 2 , 3 ] .
visualisation of the spinal cord is especially important to detect cord injury or risk of injury .
mri should therefore always be performed in ra patients with neck pain and/or neurological symptoms [ 3 , 7 ] .
fig .
radiography of the cervical spine is indicated in all ra patients with disease duration > 2 years .
it should at least include open - mouth and lateral views in neutral and flexed positions . because of the occurrence of asymptomatic cervical involvement in 17% of ra patients , it is recommended to monitor patients with intervals of 25 years depending on positivity for the rheumatoid factor .
mri is indicated in patients with neurological deficit , radiographic instability , atlanto - axial impaction and subaxial stenosis .
ct may add information in rotatory and lateral subluxation because of the possibility of secondary reconstruction in arbitrary planes and a clear visualisation of the atlanto - occipital joints diagnostic strategy . according to younes et al .
radiography of the cervical spine is indicated in all ra patients with disease duration > 2 years .
it should at least include open - mouth and lateral views in neutral and flexed positions . because of the occurrence of asymptomatic cervical involvement in 17% of ra patients , it is recommended to monitor patients with intervals of 25 years depending on positivity for the rheumatoid factor .
mri is indicated in patients with neurological deficit , radiographic instability , atlanto - axial impaction and subaxial stenosis .
ct may add information in rotatory and lateral subluxation because of the possibility of secondary reconstruction in arbitrary planes and a clear visualisation of the atlanto - occipital joints according to european classification criteria [ 8 , 9 ] , spa is divided into : ( 1 ) ankylosing spondylitis ( as ) , ( 2 ) psoriatic arthritis , ( 3 ) reactive arthritis , ( 4 ) arthritis associated with inflammatory bowel disorders ( enteropathic arthritis ) and ( 5 ) undifferentiated spa . inflammatory changes at the sacroiliac joints always occur in as and are part of most other forms of spa .
spinal changes are also a feature of spa , especially in the late stages of as . ankylosing spondylitis is the most frequent and usually the most disabling form of spa .
it has a genetic predisposition in the form of a frequent association with the human leukocyte antigen ( hla ) b27 .
it is therefore important to diagnose this disorder . according to the modified new york criteria , the diagnosis of definite as requires the following : manifest sacroiliitis by radiography ( grade 2 bilateral or unilateral grade 34 sacroiliitis ; fig .
10 ) and at least one of the following clinical criteria : ( 1 ) low back pain and stiffness for more than 3 months improving with activity , ( 2 ) limited movement of the lumbar spine and ( 3 ) reduced chest expansion .
these criteria are still used in the diagnosis of as despite the increasing use of mri to detect the disease early .
it is therefore important to know both the characteristic radiographic features and the mr features of as .
( a ) ap radiograph of the sacroiliac joints in a 28-year - old man presenting with typical definite bilateral as sacroiliitis ( grade 3 ) in the form of bilateral joint erosion accompanied by subchondral sclerosis .
( b ) initial spinal changes consisting of erosion of vertebral corners ( romanus lesion ) with vertebral squaring corresponding to th11 , th12 , l4 and l5 accompanied by condensation of the vertebral corners
( a ) ap radiograph of the sacroiliac joints in a 28-year - old man presenting with typical definite bilateral as sacroiliitis ( grade 3 ) in the form of bilateral joint erosion accompanied by subchondral sclerosis .
( b ) initial spinal changes consisting of erosion of vertebral corners ( romanus lesion ) with vertebral squaring corresponding to th11 , th12 , l4 and l5 accompanied by condensation of the vertebral corners
shiny corners ( arrows ) early radiographic spinal changes encompass erosion of vertebral corners ( romanus lesions ) causing vertebral squaring and eliciting reactive sclerosis appearing as condensation of vertebral corners ( shiny corners ; fig .
these changes are caused by inflammation at the insertion of the annulus fibrosus ( enthesitis ) at vertebral corners provoking reactive bone formation .
later on slim ossifications appear in the annulus fibrosus ( syndesmophytes ) ( fig .
the spine gradually fuses because of syndesmophytes crossing the intervertebral spaces in addition to fusion of apophyseal joints , resulting in complete spinal fusion ( bamboo spine ; fig .
the supra- and interspinous ligaments may ossify and be visible on frontal radiographs as a slim ossified streak ( fig .
the occurrence of a single central radiodense streak has been named the dagger sign .
when the ligamentous ossification occurs together with ossification of apophyseal joint capsules , there are three vertical radiodense lines on frontal radiography ( trolley - track sign ) .
11syndesmophytes and erosions in as . ( a ) lateral radiograph in a 29-year - old man with the characteristic slim ossification ( syndesmophytes ) at the periphery of the annulus fibrosus ( black arrows ) in addition to erosion of the endplates at the intervertebral
supplementary mri , ( b ) sagittal stir and ( c ) t1-weighted images show small oedematous areas in the erosion at iv l3/4 on the stir image and surrounding fatty marrow deposition on t1 as a sign of previous osseous inflammation .
there are additional erosive changes ( black arrows , c ) not clearly delineated by radiography and slight oedema at the vertebral corners ( white arrows , b ) .
( a ) ap and ( b ) lateral radiograph in a 55-year - old man showing vertebral fusion due to syndesmophytes crossing the intervertebral spaces in addition to fusion of the apophyseal joints ( bamboo spine ) . the interspinous ligaments are ossified , presenting as a slim ossified streak on the frontal radiograph ( dagger sign ; arrows ) .
mri , sagittal t1-weighted images of ( c ) the cervico - thoracic and ( d ) lumbar region , respectively , shows a general narrowing of the intervertebral discs with partial osseous fusion of the vertebral bodies , especially in the lumbar region ( arrows ) .
in addition a characteristic as deformity with reduced lumbar lordosis and thoracic kyphosis syndesmophytes and erosions in as .
( a ) lateral radiograph in a 29-year - old man with the characteristic slim ossification ( syndesmophytes ) at the periphery of the annulus fibrosus ( black arrows ) in addition to erosion of the endplates at the intervertebral ( iv ) space between l3 and l4 ( white arrow ) .
supplementary mri , ( b ) sagittal stir and ( c ) t1-weighted images show small oedematous areas in the erosion at iv l3/4 on the stir image and surrounding fatty marrow deposition on t1 as a sign of previous osseous inflammation .
there are additional erosive changes ( black arrows , c ) not clearly delineated by radiography and slight oedema at the vertebral corners ( white arrows , b ) .
( a ) ap and ( b ) lateral radiograph in a 55-year - old man showing vertebral fusion due to syndesmophytes crossing the intervertebral spaces in addition to fusion of the apophyseal joints ( bamboo spine ) . the interspinous ligaments are ossified , presenting as a slim ossified streak on the frontal radiograph ( dagger sign ; arrows ) .
mri , sagittal t1-weighted images of ( c ) the cervico - thoracic and ( d ) lumbar region , respectively , shows a general narrowing of the intervertebral discs with partial osseous fusion of the vertebral bodies , especially in the lumbar region ( arrows ) .
in addition a characteristic as deformity with reduced lumbar lordosis and thoracic kyphosis erosive changes within intervertebral spaces ( andersson lesions ) have been detected by radiography in approximately 5% of patients with as , but more frequently by mri ( fig .
. persistent movement at single intervertebral spaces may occur in an otherwise ankylosed spine , sometimes caused by non - diagnosed fractures .
this can result in pseudo - arthrosis - like changes with the formation of surrounding reactive osteophytes due to excessive mechanical load at single movable intervertebral spaces .
the diagnosis of such changes may require a ct examination to obtain adequate visualisation ( fig .
( a ) ap and ( b ) lateral radiograph showing vertebral fusion except at iv th10/11 .
supplementary ct , ( c ) sagittal and ( d ) coronal 2d reconstruction , demonstrates lack of fusion of the vertebral bodies and apophyseal joints at this level ( arrows ) .
( e ) 3d reconstruction clearly demonstrates the exuberant surrounding reactive osteophytes pseudo - arthrosis - like changes in as .
( a ) ap and ( b ) lateral radiograph showing vertebral fusion except at iv th10/11 .
supplementary ct , ( c ) sagittal and ( d ) coronal 2d reconstruction , demonstrates lack of fusion of the vertebral bodies and apophyseal joints at this level ( arrows ) .
( e ) 3d reconstruction clearly demonstrates the exuberant surrounding reactive osteophytes one of the life - threatening complications of as is spinal fracture .
non - fatal fractures have been reported to occur in up to 6% of as patients , especially in patients with long disease duration .
fractures may occur after minor trauma because of the spinal stiffness and frequently accompanying osteoporosis .
fractures often occur at intervertebral spaces , but usually involve the ankylosed posterior structures and are thereby unstable ( fig .
it is therefore mandatory to supplement a negative radiography with ct if fracture is suspected ( in the case of trauma history or a change in spinal symptoms ) .
the occurrence of cervico - thoracic fractures may cause spinal cord injury and be lethal even following minor trauma .
( a ) ap and ( b ) lateral radiograph of the thoracic spine in a 64-year - old man with advanced as and increasing back pain over 4 weeks .
the lateral view demonstrates a slight malalignment at the anterior aspects of the vertebral bodies of th9 and th10 , and the iv is irregularly narrowed on the ap view , all suggesting fracture ( arrows ) .
ct , ( c ) sagittal and ( d ) coronal reconstruction , shows fracture through the iv space and the posterior structures ( arrows ) .
there is widening of the intervertebral space anteriorly in the supine position used for ct compared with the upright position used during radiography spinal fracture in as .
( a ) ap and ( b ) lateral radiograph of the thoracic spine in a 64-year - old man with advanced as and increasing back pain over 4 weeks .
the lateral view demonstrates a slight malalignment at the anterior aspects of the vertebral bodies of th9 and th10 , and the iv is irregularly narrowed on the ap view , all suggesting fracture ( arrows ) .
ct , ( c ) sagittal and ( d ) coronal reconstruction , shows fracture through the iv space and the posterior structures ( arrows ) .
there is widening of the intervertebral space anteriorly in the supine position used for ct compared with the upright position used during radiography cross - sectional ct or mr imaging can be advantageous in the diagnosis of as changes .
ct providing a clear delineation of osseous structures is the preferred technique for visualising pseudo - arthrosis and detecting fractures ( figs . 13 , 14 ) .
ct is superior to mri in detecting minor osseous lesions such as erosion and ankylosis of the apophyseal , costo - vertebral and costo - transversal joints ( fig .
mri can visualise signs of active inflammation in the form of bone marrow and soft tissue oedema and/or contrast enhancement .
mri can , however , also detect sequelae of inflammation consisting of fatty deposition in the bone marrow and chronic structural changes such as erosion and fusion of vertebral bodies .
axial ct slices showing erosive changes ( a ) and ankylosis of costo - vertebral joints ( b ) , respectively ( arrows ) ct detection of costo - vertebral changes in as .
axial ct slices showing erosive changes ( a ) and ankylosis of costo - vertebral joints ( b ) , respectively ( arrows ) characteristic mr findings early in the disease are activity changes mainly consisting of oedema at vertebral corners and/or costo - vertebral joints ( fig .
the inflammatory changes at vertebral corners are characteristic of as . based on the occurrence of severe or multiple ( 3 ) lesions in young patients , as changes can be distinguished from degenerative changes with a high reliability . during the disease course signs of activity
detection of inflammation at apophyseal joints by mri , however , demands pronounced involvement histopathologically .
the inflammation at vertebral corners is the most valid feature and has been observed related to the development of syndesmophytes by radiography , establishing a link between signs of disease activity and chronic structural changes .
sagittal stir of ( a ) the cervico - thoracic and ( b ) the lumbar spine of the patients shown in fig .
there are multiple high signal intensity areas corresponding to vertebral corners ( white arrows ) .
additionally , osseous oedema of the costo - vertebral joints ( a , black arrows ) seen on the lateral sagittal slice of the thoracic spine .
( c ) axial post - contrast t1fs of an inflamed costo - vertebral joint confirmed the presence of joint inflammation in the form of osseous enhancement in both the vertebra and the rib ( arrows ) in addition to joint erosion .
( e ) inflammatory changes at the apophyseal joint in a 27-year - old man ; sagittal stir image of the lumbar region showing subchondral osseous oedema in the lower thoracic region ( white arrows ) , and both osseous and soft tissue oedema corresponding to the lumbar apophyseal joints ( black arrows ) .
note that the osseous oedema in the pedicle of th12 extends to the region of the costo - vertebral joint .
( f ) coronal post - contrast t1fs of the lumbar spine shows additional enhancement corresponding to the interspinous ligament between l2 and l3 ( arrows ) activity changes in as by mri .
sagittal stir of ( a ) the cervico - thoracic and ( b ) the lumbar spine of the patients shown in fig .
there are multiple high signal intensity areas corresponding to vertebral corners ( white arrows ) .
additionally , osseous oedema of the costo - vertebral joints ( a , black arrows ) seen on the lateral sagittal slice of the thoracic spine .
( c ) axial post - contrast t1fs of an inflamed costo - vertebral joint confirmed the presence of joint inflammation in the form of osseous enhancement in both the vertebra and the rib ( arrows ) in addition to joint erosion .
( e ) inflammatory changes at the apophyseal joint in a 27-year - old man ; sagittal stir image of the lumbar region showing subchondral osseous oedema in the lower thoracic region ( white arrows ) , and both osseous and soft tissue oedema corresponding to the lumbar apophyseal joints ( black arrows ) .
note that the osseous oedema in the pedicle of th12 extends to the region of the costo - vertebral joint .
( f ) coronal post - contrast t1fs of the lumbar spine shows additional enhancement corresponding to the interspinous ligament between l2 and l3 ( arrows ) chronic as changes detectable by mri mainly consist of fatty marrow deposition at vertebral corners ( fig .
17 ) , erosion ( fig . 11 ) and vertebral fusion in advanced disease ( fig .
. fatty marrow deposition seems to be an important sign of chronicity being significantly correlated with radiographic changes , in particular vertebral squaring .
11 ) and can present with signs of active inflammation and/or surrounding fatty marrow deposition compatible with sequels of osseous inflammation .
syndesmophytes , however , may not always be visible by mri because they may be difficult to distinguish from fibrous tissue unless there is concomitant active inflammation or fatty deposition ( figs . 11 , 16 ) [ 15 , 20 ] .
sagittal t1 of ( a ) the cervico - thoracic and ( b ) the lumbar spine of the patients shown in fig .
there are multiple fatty marrow depositions at vertebral corners and also posteriorly in thoracic vertebral bodies ( b , arrows ) .
this was observed to have developed since the mri performed 3 years previously ( shown in fig .
16a - d ) and corresponds to areas of previous inflammation chronic changes in as by mri .
sagittal t1 of ( a ) the cervico - thoracic and ( b ) the lumbar spine of the patients shown in fig .
there are multiple fatty marrow depositions at vertebral corners and also posteriorly in thoracic vertebral bodies ( b , arrows ) .
this was observed to have developed since the mri performed 3 years previously ( shown in fig .
16a - d ) and corresponds to areas of previous inflammation the possibility of visualising disease activity by mri has increased its use to monitor as , especially during anti - tnf ( anti - tumour necrosis factor ) therapy [ 21 , 22 ] .
several studies have shown that mr changes are frequent in the thoracic spine ( fig .
it is therefore important to examine the entire spine using sagittal stir or t2 fat - saturated ( fs ) and t1-weighted sequences .
supplementary axial slices can be necessary for visualising involvement of apophyseal , costo - vertebral and costo - transversal joints ( fig .
post - contrast t1fs sequences can sometimes be advantageous as they provide better anatomical delineation .
additionally , dynamic contrast - enhanced mri may be superior to static mri in monitoring disease activity during anti - tnf therapy .
whole - body mri gives the possibility of detecting involvement in other areas without losing important information about spinal and sacroiliac joint involvement [ 28 , 29 ] .
radiographic changes in reactive and psoriatic arthritis are often characterised by voluminous non - marginal syndesmophytes ( parasyndesmophytes ) or coalescing ossification of the paravertebral ligaments in addition to asymmetrical sacroiliitis ( fig .
( a ) ap and ( b ) lateral radiograph of the lumbar spine in a 48-year - old man with psa showing voluminous paravertebral new bone formation ( arrows ) in addition to fusion of the second and third vertebral bodies .
( c ) ap radiograph of the thoraco - lumbar junction in a female patient with axial psa demonstrating coalescing paravertebral ossifications ( arrows ) psoriatic arthritis ( psa ) , paravertebral ossifications .
( a ) ap and ( b ) lateral radiograph of the lumbar spine in a 48-year - old man with psa showing voluminous paravertebral new bone formation ( arrows ) in addition to fusion of the second and third vertebral bodies .
( c ) ap radiograph of the thoraco - lumbar junction in a female patient with axial psa demonstrating coalescing paravertebral ossifications ( arrows ) reactive arthritis is self - limiting in most patients .
however , in patients with chronic reactive arthritis and hla b27 the axial changes may progress to changes somewhat similar to those seen in as and can then be regarded as as elicited by infection .
axial psoriatic arthritis ( psa ) occurs in approximately 50% of patients with peripheral psa .
it differs radiographically from as by the voluminous paravertebral ossifications and the occurrence of spinal changes without concomitant sacroiliitis in 10% of patients .
axial psa may be clinically silent , and involvement of the cervical spine is frequent ( atlanto - axial or apophyseal joint changes ) .
the cervical changes may include atlanto - axial instability as seen in ra ( fig .
19 ) , but the pathogenesis and thereby imaging findings are different . in psa radiography and ct
this is elicited by osseous inflammation ( osteitis ) and/or inflammation at ligament / tendon attachments ( enthesitis ) detectable by mri ( fig .
osteitis is often a feature of spinal psa and can occur together with paravertebral ossification / parasyndesmophytes and erosion of vertebral plates ( fig . 20 ) .
the above - mentioned and illustrated mr findings in psa are based on personal observations and seem to reflect the radiographic changes encompassing a mixture of osteitis , enthesitis and erosion . unfortunately , there is a lack of systematic description of spinal changes in psa by mri . some of the patients described under the term sapho ( synovitis , acne , pustulosis , hyperostosis , osteitis ) syndrome may have psa .
sapho is a collective term often used for inflammatory disorders primarily presenting with osseous hyperostosis and sclerosis , and they are frequently associated with skin disorders .
the most commonly affected site in sapho is the anterior chest followed by the spine . the psa changes shown in fig
. 20 are characterised by hyperostosis and sclerosis , both main features of sapho .
( a ) lateral radiographs in the neutral position and ( b ) during flexion in a 61-year - old woman show atlanto - axial instability with a 4-mm distance between the anterior arc and the dens ( white line ) .
additionally , ankylosis of the apophyseal joints ( black arrows ) and new bone formation anterior to the c4 - 7 vertebral bodies ( white arrows ) .
ct , ( c ) axial slice and coronal reconstruction of the dens area , demonstrates new bone formation in the atlanto - axial region ( arrows ) ; ( d ) coronal reconstruction of the lower cervical region shows voluminous new bone formation on the right side of the vertebral bodies ( arrows ) .
mri , ( e ) sagittal stir and ( f ) t1-weighted images , shows homogeneous osseous inflammation corresponding to the dens ( arrows ) with surrounding irregular oedema compatible with a mixture of osteitis and enthesitis .
note that the anterior new bone formation visualised by radiography is difficult to detect on mrifig .
( a ) ap and ( b ) lateral radiograph in a 50-year - old man show voluminous paravertebral ossifications anteriorly and at the right side of the third lumbar vertebra and adjacent iv spaces .
mri , ( c ) sagittal stir , ( d ) t1 and ( e ) post - contrast t1-weighted images , demonstrates manifest osseous inflammation ( osteitis ) in the form of oedema and enhancement of the vertebral body , slight enhancement in the paravertebral new bone formation and erosion of the upper vertebral plate compatible with a mixture of osteitis , enthesitis and erosive changes cervical psa .
( a ) lateral radiographs in the neutral position and ( b ) during flexion in a 61-year - old woman show atlanto - axial instability with a 4-mm distance between the anterior arc and the dens ( white line ) .
additionally , ankylosis of the apophyseal joints ( black arrows ) and new bone formation anterior to the c4 - 7 vertebral bodies ( white arrows ) .
ct , ( c ) axial slice and coronal reconstruction of the dens area , demonstrates new bone formation in the atlanto - axial region ( arrows ) ; ( d ) coronal reconstruction of the lower cervical region shows voluminous new bone formation on the right side of the vertebral bodies ( arrows ) .
mri , ( e ) sagittal stir and ( f ) t1-weighted images , shows homogeneous osseous inflammation corresponding to the dens ( arrows ) with surrounding irregular oedema compatible with a mixture of osteitis and enthesitis .
note that the anterior new bone formation visualised by radiography is difficult to detect on mri lumbar psa .
( a ) ap and ( b ) lateral radiograph in a 50-year - old man show voluminous paravertebral ossifications anteriorly and at the right side of the third lumbar vertebra and adjacent iv spaces .
mri , ( c ) sagittal stir , ( d ) t1 and ( e ) post - contrast t1-weighted images , demonstrates manifest osseous inflammation ( osteitis ) in the form of oedema and enhancement of the vertebral body , slight enhancement in the paravertebral new bone formation and erosion of the upper vertebral plate compatible with a mixture of osteitis , enthesitis and erosive changes in patients with enteropathic arthritis associated with crohn s disease or ulcerative colitis , the spine is often osteoporotic with various accompanying spa features by radiography , mostly as - like changes .
however , by mri there may be more pronounced inflammation in the posterior ligaments than seen in the other forms of spa ( fig . 21 ) .
sagittal stir image of the lumbar spine in a 27-year - old man with ulcerative colitis demonstrates oedema corresponding to the interspinous ligaments ( arrows ) and spinous processes as signs of inflammation .
there are only minimal activity changes corresponding to the vertebral bodies , located to the anterior vertebral corners enteropathic spa .
sagittal stir image of the lumbar spine in a 27-year - old man with ulcerative colitis demonstrates oedema corresponding to the interspinous ligaments ( arrows ) and spinous processes as signs of inflammation .
there are only minimal activity changes corresponding to the vertebral bodies , located to the anterior vertebral corners
involvement in ra is usually located in the cervical spine where erosive changes are predominantly seen in the atlanto - axial region .
inflamed and thickened synovium ( pannus ) can occur around the odontoid process ( dens ) and cause bone erosion and destruction of surrounding ligaments , most seriously if the posterior transverse ligament is involved .
laxity or rupture of the transverse ligament causes instability with a potential risk of spinal cord injury .
cervical ra involvement is a progressive , serious condition with reduced lifetime expectancy , and its diagnosis is therefore important [ 2 , 3 ] .
it should always include a lateral view in a flexed position compared with a neutral position in addition to special views of the dens area to detect any lesions and/or instability ( fig . 1 ) .
a supplementary lateral view during extension can be useful to assess reducibility of atlanto - axial subluxation possibly limited by pannus tissue between the anterior arc of the atlas and dens .
( a ) lateral radiographs in neutral position and ( b ) during flexion in addition to ( c ) lateral and ( d ) anterior - posterior ( ap ) open - mouth view of the atlanto - axial region ( 45-year - old woman ) .
the flexion view ( b ) shows abnormal distance ( > 3 mm ) between the posterior aspect of the anterior arc of the atlas and the anterior aspect of the dens ( black line ) .
note that the spino - laminar line of the atlas ( arrow ) does not align with that of the other vertebrae , confirming the presence of anterior subluxation , but there is no stenosis of the atlanto - axial canal ; the posterior atlanto - dental interval ( white line ) is > 14 mm .
the open - mouth view ( d ) shows erosion at the base of the dens ( arrow ) .
( a ) and ( b ) show concomitant disc degenerative changes at the c4c6 level standard radiography of the cervical spine in rheumatoid arthritis ( ra ) .
( a ) lateral radiographs in neutral position and ( b ) during flexion in addition to ( c ) lateral and ( d ) anterior - posterior ( ap ) open - mouth view of the atlanto - axial region ( 45-year - old woman ) .
the flexion view ( b ) shows abnormal distance ( > 3 mm ) between the posterior aspect of the anterior arc of the atlas and the anterior aspect of the dens ( black line ) .
note that the spino - laminar line of the atlas ( arrow ) does not align with that of the other vertebrae , confirming the presence of anterior subluxation , but there is no stenosis of the atlanto - axial canal ; the posterior atlanto - dental interval ( white line ) is > 14 mm .
the open - mouth view ( d ) shows erosion at the base of the dens ( arrow ) .
( a ) and ( b ) show concomitant disc degenerative changes at the c4c6 level anterior atlanto - axial subluxation is the most frequent form of ra instability in the occipito - atlanto - axial region , but lateral , rotatory and vertical subluxation can also occur .
distance between the posterior aspect of the anterior arc of the atlas and the anterior aspect of the dens exceeding 3 mm in a neutral position and/or during flexion ( fig . 1 ) .
it may cause stenosis of the atlanto - axial canal presenting as a posterior atlanto - dental interval < 14 mm ( fig . 1 ) .
displacement of the lateral masses of the atlas more than 2 mm in relation to that of the axis and asymmetry of the lateral masses relative to the dens , respectively ( fig . 2 ) .
rotatory and lateral subluxation is diagnosed on open - mouth anterior - posterior ( ap ) radiographs .
anterior subluxation often coexists because of the close anatomical relation between the atlas and the axis .
there is narrowing of the atlanto - axial joints with superficial erosions ( black arrow ) and lateral displacement of the axis with respect to the lateral masses of the atlas ( white arrow ) ; in addition signs indicating rotatory displacement with asymmetry of the distance between the dens and the lateral masses of the atlas lateral and rotatory atlanto - axial subluxation .
there is narrowing of the atlanto - axial joints with superficial erosions ( black arrow ) and lateral displacement of the axis with respect to the lateral masses of the atlas ( white arrow ) ; in addition signs indicating rotatory displacement with asymmetry of the distance between the dens and the lateral masses of the atlas the anterior arc of the atlas moves over the odontoid process .
. is also referred to as atlanto - axial impaction , basilar invagination or cranial setting , and is defined as migration of the odontoid tip proximal to mcrae s line corresponding to the occipital foramen .
this line can be difficult to define on radiographs , and vertical subluxation has therefore also been defined by several other methods .
migration of the tip of the odontoid process > 4.5 mm above mcgregor s line ( between the postero - superior aspect of the hard palate and the most caudal point of the occipital curve ) indicates vertical subluxation ( fig .
( a ) lateral normal radiograph in neutral position showing the location of mcgregor s line ( black ) between the postero - superior aspect of the hard palate and the most caudal point of the occipital curve .
migration of the tip of the dens > 4.5 mm above mcgregor s line indicates vertical subluxation . the distance indicated by the white line between mcgregor s line and the midpoint of the inferior margin of the body of axis
is used to evaluate vertical subluxation according to redlund - johnell and pettersson s method .
a distance less than 34 mm in men and 29 mm in women indicates vertical subluxation .
( b ) sagittal ct reconstruction of a normal cervical spine showing the location of mcrae s line corresponding to the occipital foramen and the division of the axis into three equal portions used by clark s method for diagnosing vertical subluxation .
if the anterior arc of the atlas is in level with the middle or caudal third of the axis there is slight and pronounced vertical subluxation , respectively .
( c ) ranawat s method includes determination of the distance between the centre of the second cervical pedicle and the transverse axis of the atlas .
a distance less than 15 mm in males and 13 mm in females indicates vertical subluxation vertical atlanto - axial subluxation , measurement methods .
( a ) lateral normal radiograph in neutral position showing the location of mcgregor s line ( black ) between the postero - superior aspect of the hard palate and the most caudal point of the occipital curve .
migration of the tip of the dens > 4.5 mm above mcgregor s line indicates vertical subluxation . the distance indicated by the white line between mcgregor s line and the midpoint of the inferior margin of the body of axis
is used to evaluate vertical subluxation according to redlund - johnell and pettersson s method .
a distance less than 34 mm in men and 29 mm in women indicates vertical subluxation .
( b ) sagittal ct reconstruction of a normal cervical spine showing the location of mcrae s line corresponding to the occipital foramen and the division of the axis into three equal portions used by clark s method for diagnosing vertical subluxation .
if the anterior arc of the atlas is in level with the middle or caudal third of the axis there is slight and pronounced vertical subluxation , respectively .
( c ) ranawat s method includes determination of the distance between the centre of the second cervical pedicle and the transverse axis of the atlas .
a distance less than 15 mm in males and 13 mm in females indicates vertical subluxation the occurrence of dens erosion can , however , make this measurement difficult to obtain .
the redlund - johnell method is therefore based on the minimum distance between mcgregor s line and the midpoint of the inferior margin of the body of the axis on a lateral radiograph in a neutral position ( fig .
( described in ) includes assessment of the location of the atlas by dividing the axis into three equal portions on a lateral radiograph .
location of the anterior arc of the atlas in level with the middle or caudal third of the axis indicates vertical subluxation ( fig .
ranawat et al . have proposed using the distance between the centre of the second cervical pedicle and the transverse axis of the atlas at the odontoid process ( fig .
3 ) . to obtain the diagnosis of vertical subluxation a combination of the redlund - johnell , clark and ranawat methods has been recommended ( described in ) .
if any of these methods suggests vertical subluxation mri should be performed to visualise the spinal cord ( fig .
4 ) . using this combination of methods vertical subluxation will be missed in only 6% of patients .
it is mandatory to diagnose vertical subluxation ; this can be fatal because of the proximity of the dens to the medulla oblongata and the proximal portion of the spinal cord .
risk of cord compression / injury occurs , especially in patients with flexion instability accompanied by erosive changes in the atlanto - axial and/or atlanto - occipital joints , causing the vertical subluxation with protrusion of the dens into the occipital foramen ( figs . 4 , 5 ) .
( a ) lateral radiograph with mcgregor s line ( black line ; 61-year - old man with ra ) .
the tip of the dens is difficult to define , but measurement according to redlund - johnell s method ( white line ) results in a distance of 27 mm , which is below the normal limit . in accordance with this ,
the anterior arc of the atlas is level with the middle third of the axis .
( b ) ranawat s method , the distance between the centre of the second cervical pedicle and the transverse axis of the atlas is below the normal limit ( 9 mm ) .
. supplementary mri , ( c ) sagittal stir and ( d ) t1-weighted images show erosion of the dens and protrusion of the tip into the occipital foramen causing narrowing of the spinal canal to 9 mm , but persistence of cerebrospinal fluid around the cord . there is a 9-mm - thick mass of pannus tissue between the dens and anterior arc ( black line ) exhibiting small areas with high signal intensity on the stir image ( arrow ) compatible with slight activity , but signal void fibrous pannus tissue predominatesfig .
mri of the cervical spine in a 69-year - old woman with advanced peripheral ra , neck pain and clinical signs of myelopathy .
( a ) sagittal stir , ( b ) sagittal t1 and ( c ) axial t2 fat - saturated ( fs ) images show erosion of the dens and protrusion of the tip into the occipital foramen causing compression of the spinal cord , which exhibits irregular signal intensity ( white arrows ) .
the osseous spinal canal has a width of approximately 7 mm ( black line ) .
there is heterogeneous signal intensity pannus surrounding the dens compatible with a mixture of fibrotic and oedematous pannus tissue ( black arrows ) in the widened space between the dens and the anterior arc of the atlas vertical subluxation .
( a ) lateral radiograph with mcgregor s line ( black line ; 61-year - old man with ra ) .
the tip of the dens is difficult to define , but measurement according to redlund - johnell s method ( white line ) results in a distance of 27 mm , which is below the normal limit . in accordance with this ,
the anterior arc of the atlas is level with the middle third of the axis .
( b ) ranawat s method , the distance between the centre of the second cervical pedicle and the transverse axis of the atlas is below the normal limit ( 9 mm ) .
supplementary mri , ( c ) sagittal stir and ( d ) t1-weighted images show erosion of the dens and protrusion of the tip into the occipital foramen causing narrowing of the spinal canal to 9 mm , but persistence of cerebrospinal fluid around the cord .
there is a 9-mm - thick mass of pannus tissue between the dens and anterior arc ( black line ) exhibiting small areas with high signal intensity on the stir image ( arrow ) compatible with slight activity , but signal void fibrous pannus tissue predominates vertical subluxation with spinal cord compression .
mri of the cervical spine in a 69-year - old woman with advanced peripheral ra , neck pain and clinical signs of myelopathy .
( a ) sagittal stir , ( b ) sagittal t1 and ( c ) axial t2 fat - saturated ( fs ) images show erosion of the dens and protrusion of the tip into the occipital foramen causing compression of the spinal cord , which exhibits irregular signal intensity ( white arrows ) .
the osseous spinal canal has a width of approximately 7 mm ( black line ) .
there is heterogeneous signal intensity pannus surrounding the dens compatible with a mixture of fibrotic and oedematous pannus tissue ( black arrows ) in the widened space between the dens and the anterior arc of the atlas also occur in the form of arthritis of the apophyseal and/or uncovertebral joints , appearing as narrowing and superficial erosions by radiography .
it can cause instability in the c2-th1 region , which is mainly seen in patients with severe chronic peripheral arthritis .
it is defined as at least 3 mm forward slippage of a vertebra relative to the underlying vertebra by radiography including a flexion view ( fig .
changes are particularly characteristic at the c34 and c45 level , but multiple levels may be involved , producing a typical stepladder appearance on lateral radiographs .
the condition is serious if the subaxial sagittal spinal canal diameter is < 14 mm , implying a possibility of spinal cord compression .
the instability may progress over time , especially if the c1c2 region is stabilised surgically ( fig .
( a ) flexion view in a 64-year - old woman with advanced peripheral ra showing anterior atlanto - axial instability as well as subaxial instability at multiple levels .
( b ) flexion view 2 years later after surgical stabilisation of the atlanto - axial region demonstrates progression of the subaxial instability , especially between c3 and c4 ( white arrow ) .
there is a characteristic stepladder appearance , which also occurred on the initial radiographs ( a ) , but is less pronounced subaxial instability .
( a ) flexion view in a 64-year - old woman with advanced peripheral ra showing anterior atlanto - axial instability as well as subaxial instability at multiple levels .
( b ) flexion view 2 years later after surgical stabilisation of the atlanto - axial region demonstrates progression of the subaxial instability , especially between c3 and c4 ( white arrow ) .
there is a characteristic stepladder appearance , which also occurred on the initial radiographs ( a ) , but is less pronounced discitis - like changes and spinous process erosion may also be detected by radiography in ra , but are relatively rare , whereas concomitant degenerative changes occur occasionally ( fig . 1 ) .
cross - sectional imaging in the form of ct and mri eliminates overprojecting structures and can improve the detection of ra changes .
osseous changes ( erosions , etc . ) can be clearly delineated by ct . additionally , mri visualises soft tissue structures ( pannus ; spinal cord , etc . ) , signs of disease activity and sequelae of inflammation in the form of fibrous pannus .
these advantages of ct and mri in patients with atlanto - axial involvement are illustrated in figs .
7 and 8 , including the possibility of detecting signs of arthritis by mri before the occurrence of erosive changes ( fig .
supplementary ct and ( b - f ) mri of the patient shown in fig . 1 .
ct demonstrates erosion not only at the base of the dens , but also at the tip and at the atlanto - axial and atlanto - occipital joints , which are difficult to visualise by radiography .
mri , ( b ) sagittal stir and ( c ) sagittal t1 of the entire cervical spine and post - contrast t1fs images of the atlanto - axial region , ( d ) sagittal , ( e ) coronal and ( f ) axial .
oedematous voluminous pannus surrounding the dens is seen on the stir and t1 images ( black arrows ) in addition to c4/5 and c5/6 disc degeneration with posterior protrusion of the disc at c4/5 .
the post - contrast t1fs images confirm the presence of vascularised enhancing pannus around the dens ( white arrows ) and demonstrate improved anatomical delineation compared with the stir image .
mri in a 41-year - old woman with peripheral erosive ra and neck pain , but normal cervical radiography .
( a ) post - contrast axial and ( b ) coronal tifs images show signs of active arthritis with synovial contrast enhancement at the left atlanto - axial joint in addition to enhancing pannus tissue at the left side of the dens ( white arrows ) .
there is also a subchondral enhancing area in the axis ( black arrow ) compatible with a pre - erosive lesion advantages of ct and mri .
( a ) supplementary ct and ( b - f ) mri of the patient shown in fig
ct demonstrates erosion not only at the base of the dens , but also at the tip and at the atlanto - axial and atlanto - occipital joints , which are difficult to visualise by radiography .
mri , ( b ) sagittal stir and ( c ) sagittal t1 of the entire cervical spine and post - contrast t1fs images of the atlanto - axial region , ( d ) sagittal , ( e ) coronal and ( f ) axial .
oedematous voluminous pannus surrounding the dens is seen on the stir and t1 images ( black arrows ) in addition to c4/5 and c5/6 disc degeneration with posterior protrusion of the disc at c4/5 .
the post - contrast t1fs images confirm the presence of vascularised enhancing pannus around the dens ( white arrows ) and demonstrate improved anatomical delineation compared with the stir image .
mri in a 41-year - old woman with peripheral erosive ra and neck pain , but normal cervical radiography .
( a ) post - contrast axial and ( b ) coronal tifs images show signs of active arthritis with synovial contrast enhancement at the left atlanto - axial joint in addition to enhancing pannus tissue at the left side of the dens ( white arrows ) .
there is also a subchondral enhancing area in the axis ( black arrow ) compatible with a pre - erosive lesion a diagnostic strategy according to younes et al .
this includes an indication for radiography in all ra patients with disease duration > 2 years as cervical involvement may occur in over 70% of patients and has been reported to be asymptomatic in 17% of ra patients .
it is recommended to monitor patients with manifest peripheral erosions accompanied by rf ( rheumatoid factor ) and anticcp ( antibodies to cyclic citrullinated peptide ) positivity every second year and patients with few peripheral erosions and rf negativity at 5-year intervals .
mri is indicated in patients with neurological deficit , radiographic instability , vertical subluxation and subaxial stenosis [ 2 , 3 ] .
visualisation of the spinal cord is especially important to detect cord injury or risk of injury .
mri should therefore always be performed in ra patients with neck pain and/or neurological symptoms [ 3 , 7 ] .
radiography of the cervical spine is indicated in all ra patients with disease duration > 2 years .
it should at least include open - mouth and lateral views in neutral and flexed positions . because of the occurrence of asymptomatic cervical involvement in 17% of ra patients
, it is recommended to monitor patients with intervals of 25 years depending on positivity for the rheumatoid factor .
mri is indicated in patients with neurological deficit , radiographic instability , atlanto - axial impaction and subaxial stenosis .
ct may add information in rotatory and lateral subluxation because of the possibility of secondary reconstruction in arbitrary planes and a clear visualisation of the atlanto - occipital joints diagnostic strategy . according to younes et al .
radiography of the cervical spine is indicated in all ra patients with disease duration > 2 years .
it should at least include open - mouth and lateral views in neutral and flexed positions . because of the occurrence of asymptomatic cervical involvement in 17% of ra patients
, it is recommended to monitor patients with intervals of 25 years depending on positivity for the rheumatoid factor .
mri is indicated in patients with neurological deficit , radiographic instability , atlanto - axial impaction and subaxial stenosis .
ct may add information in rotatory and lateral subluxation because of the possibility of secondary reconstruction in arbitrary planes and a clear visualisation of the atlanto - occipital joints
according to european classification criteria [ 8 , 9 ] , spa is divided into : ( 1 ) ankylosing spondylitis ( as ) , ( 2 ) psoriatic arthritis , ( 3 ) reactive arthritis , ( 4 ) arthritis associated with inflammatory bowel disorders ( enteropathic arthritis ) and ( 5 ) undifferentiated spa . inflammatory changes at the sacroiliac joints always occur in as and are part of most other forms of spa .
spinal changes are also a feature of spa , especially in the late stages of as .
it has a genetic predisposition in the form of a frequent association with the human leukocyte antigen ( hla ) b27 .
it is therefore important to diagnose this disorder . according to the modified new york criteria , the diagnosis of definite as requires the following : manifest sacroiliitis by radiography ( grade 2 bilateral or unilateral grade 34 sacroiliitis ; fig .
10 ) and at least one of the following clinical criteria : ( 1 ) low back pain and stiffness for more than 3 months improving with activity , ( 2 ) limited movement of the lumbar spine and ( 3 ) reduced chest expansion .
these criteria are still used in the diagnosis of as despite the increasing use of mri to detect the disease early .
it is therefore important to know both the characteristic radiographic features and the mr features of as .
fig .
10relatively early changes in ankylosing spondylitis ( as ) . ( a ) ap radiograph of the sacroiliac joints in a 28-year - old man presenting with typical definite bilateral as sacroiliitis ( grade 3 ) in the form of bilateral joint erosion accompanied by subchondral sclerosis .
( b ) initial spinal changes consisting of erosion of vertebral corners ( romanus lesion ) with vertebral squaring corresponding to th11 , th12 , l4 and l5 accompanied by condensation of the vertebral corners
( a ) ap radiograph of the sacroiliac joints in a 28-year - old man presenting with typical definite bilateral as sacroiliitis ( grade 3 ) in the form of bilateral joint erosion accompanied by subchondral sclerosis .
( b ) initial spinal changes consisting of erosion of vertebral corners ( romanus lesion ) with vertebral squaring corresponding to th11 , th12 , l4 and l5 accompanied by condensation of the vertebral corners
shiny corners ( arrows ) early radiographic spinal changes encompass erosion of vertebral corners ( romanus lesions ) causing vertebral squaring and eliciting reactive sclerosis appearing as condensation of vertebral corners ( shiny corners ; fig .
these changes are caused by inflammation at the insertion of the annulus fibrosus ( enthesitis ) at vertebral corners provoking reactive bone formation .
later on slim ossifications appear in the annulus fibrosus ( syndesmophytes ) ( fig .
the spine gradually fuses because of syndesmophytes crossing the intervertebral spaces in addition to fusion of apophyseal joints , resulting in complete spinal fusion ( bamboo spine ; fig .
the supra- and interspinous ligaments may ossify and be visible on frontal radiographs as a slim ossified streak ( fig . 12 ) .
the occurrence of a single central radiodense streak has been named the dagger sign .
when the ligamentous ossification occurs together with ossification of apophyseal joint capsules , there are three vertical radiodense lines on frontal radiography ( trolley - track sign ) .
( a ) lateral radiograph in a 29-year - old man with the characteristic slim ossification ( syndesmophytes ) at the periphery of the annulus fibrosus ( black arrows ) in addition to erosion of the endplates at the intervertebral ( iv ) space between l3 and l4 ( white arrow ) .
supplementary mri , ( b ) sagittal stir and ( c ) t1-weighted images show small oedematous areas in the erosion at iv l3/4 on the stir image and surrounding fatty marrow deposition on t1 as a sign of previous osseous inflammation .
there are additional erosive changes ( black arrows , c ) not clearly delineated by radiography and slight oedema at the vertebral corners ( white arrows , b ) .
( a ) ap and ( b ) lateral radiograph in a 55-year - old man showing vertebral fusion due to syndesmophytes crossing the intervertebral spaces in addition to fusion of the apophyseal joints ( bamboo spine ) . the interspinous ligaments are ossified , presenting as a slim ossified streak on the frontal radiograph ( dagger sign ; arrows ) .
mri , sagittal t1-weighted images of ( c ) the cervico - thoracic and ( d ) lumbar region , respectively , shows a general narrowing of the intervertebral discs with partial osseous fusion of the vertebral bodies , especially in the lumbar region ( arrows ) .
in addition a characteristic as deformity with reduced lumbar lordosis and thoracic kyphosis syndesmophytes and erosions in as .
( a ) lateral radiograph in a 29-year - old man with the characteristic slim ossification ( syndesmophytes ) at the periphery of the annulus fibrosus ( black arrows ) in addition to erosion of the endplates at the intervertebral ( iv ) space between l3 and l4 ( white arrow ) .
supplementary mri , ( b ) sagittal stir and ( c ) t1-weighted images show small oedematous areas in the erosion at iv l3/4 on the stir image and surrounding fatty marrow deposition on t1 as a sign of previous osseous inflammation .
there are additional erosive changes ( black arrows , c ) not clearly delineated by radiography and slight oedema at the vertebral corners ( white arrows , b ) .
( a ) ap and ( b ) lateral radiograph in a 55-year - old man showing vertebral fusion due to syndesmophytes crossing the intervertebral spaces in addition to fusion of the apophyseal joints ( bamboo spine ) .
the interspinous ligaments are ossified , presenting as a slim ossified streak on the frontal radiograph ( dagger sign ; arrows ) .
mri , sagittal t1-weighted images of ( c ) the cervico - thoracic and ( d ) lumbar region , respectively , shows a general narrowing of the intervertebral discs with partial osseous fusion of the vertebral bodies , especially in the lumbar region ( arrows ) .
in addition a characteristic as deformity with reduced lumbar lordosis and thoracic kyphosis erosive changes within intervertebral spaces ( andersson lesions ) have been detected by radiography in approximately 5% of patients with as , but more frequently by mri ( fig .
. persistent movement at single intervertebral spaces may occur in an otherwise ankylosed spine , sometimes caused by non - diagnosed fractures .
this can result in pseudo - arthrosis - like changes with the formation of surrounding reactive osteophytes due to excessive mechanical load at single movable intervertebral spaces .
the diagnosis of such changes may require a ct examination to obtain adequate visualisation ( fig .
( a ) ap and ( b ) lateral radiograph showing vertebral fusion except at iv th10/11 .
supplementary ct , ( c ) sagittal and ( d ) coronal 2d reconstruction , demonstrates lack of fusion of the vertebral bodies and apophyseal joints at this level ( arrows ) .
( e ) 3d reconstruction clearly demonstrates the exuberant surrounding reactive osteophytes pseudo - arthrosis - like changes in as .
( a ) ap and ( b ) lateral radiograph showing vertebral fusion except at iv th10/11 .
supplementary ct , ( c ) sagittal and ( d ) coronal 2d reconstruction , demonstrates lack of fusion of the vertebral bodies and apophyseal joints at this level ( arrows ) .
( e ) 3d reconstruction clearly demonstrates the exuberant surrounding reactive osteophytes one of the life - threatening complications of as is spinal fracture .
non - fatal fractures have been reported to occur in up to 6% of as patients , especially in patients with long disease duration .
fractures may occur after minor trauma because of the spinal stiffness and frequently accompanying osteoporosis .
fractures often occur at intervertebral spaces , but usually involve the ankylosed posterior structures and are thereby unstable ( fig .
it is therefore mandatory to supplement a negative radiography with ct if fracture is suspected ( in the case of trauma history or a change in spinal symptoms ) .
the occurrence of cervico - thoracic fractures may cause spinal cord injury and be lethal even following minor trauma .
( a ) ap and ( b ) lateral radiograph of the thoracic spine in a 64-year - old man with advanced as and increasing back pain over 4 weeks .
the lateral view demonstrates a slight malalignment at the anterior aspects of the vertebral bodies of th9 and th10 , and the iv is irregularly narrowed on the ap view , all suggesting fracture ( arrows ) .
ct , ( c ) sagittal and ( d ) coronal reconstruction , shows fracture through the iv space and the posterior structures ( arrows ) .
there is widening of the intervertebral space anteriorly in the supine position used for ct compared with the upright position used during radiography spinal fracture in as .
( a ) ap and ( b ) lateral radiograph of the thoracic spine in a 64-year - old man with advanced as and increasing back pain over 4 weeks .
the lateral view demonstrates a slight malalignment at the anterior aspects of the vertebral bodies of th9 and th10 , and the iv is irregularly narrowed on the ap view , all suggesting fracture ( arrows ) .
ct , ( c ) sagittal and ( d ) coronal reconstruction , shows fracture through the iv space and the posterior structures ( arrows ) .
there is widening of the intervertebral space anteriorly in the supine position used for ct compared with the upright position used during radiography cross - sectional ct or mr imaging can be advantageous in the diagnosis of as changes .
ct providing a clear delineation of osseous structures is the preferred technique for visualising pseudo - arthrosis and detecting fractures ( figs . 13 , 14 ) .
ct is superior to mri in detecting minor osseous lesions such as erosion and ankylosis of the apophyseal , costo - vertebral and costo - transversal joints ( fig .
mri can visualise signs of active inflammation in the form of bone marrow and soft tissue oedema and/or contrast enhancement .
mri can , however , also detect sequelae of inflammation consisting of fatty deposition in the bone marrow and chronic structural changes such as erosion and fusion of vertebral bodies .
axial ct slices showing erosive changes ( a ) and ankylosis of costo - vertebral joints ( b ) , respectively ( arrows ) ct detection of costo - vertebral changes in as .
axial ct slices showing erosive changes ( a ) and ankylosis of costo - vertebral joints ( b ) , respectively ( arrows ) characteristic mr findings early in the disease are activity changes mainly consisting of oedema at vertebral corners and/or costo - vertebral joints ( fig .
the inflammatory changes at vertebral corners are characteristic of as . based on the occurrence of severe or multiple ( 3 ) lesions in young patients , as changes can be distinguished from degenerative changes with a high reliability . during the disease course signs of activity
detection of inflammation at apophyseal joints by mri , however , demands pronounced involvement histopathologically .
the inflammation at vertebral corners is the most valid feature and has been observed related to the development of syndesmophytes by radiography , establishing a link between signs of disease activity and chronic structural changes .
sagittal stir of ( a ) the cervico - thoracic and ( b ) the lumbar spine of the patients shown in fig .
there are multiple high signal intensity areas corresponding to vertebral corners ( white arrows ) .
additionally , osseous oedema of the costo - vertebral joints ( a , black arrows ) seen on the lateral sagittal slice of the thoracic spine .
( c ) axial post - contrast t1fs of an inflamed costo - vertebral joint confirmed the presence of joint inflammation in the form of osseous enhancement in both the vertebra and the rib ( arrows ) in addition to joint erosion .
( e ) inflammatory changes at the apophyseal joint in a 27-year - old man ; sagittal stir image of the lumbar region showing subchondral osseous oedema in the lower thoracic region ( white arrows ) , and both osseous and soft tissue oedema corresponding to the lumbar apophyseal joints ( black arrows ) .
note that the osseous oedema in the pedicle of th12 extends to the region of the costo - vertebral joint .
( f ) coronal post - contrast t1fs of the lumbar spine shows additional enhancement corresponding to the interspinous ligament between l2 and l3 ( arrows ) activity changes in as by mri .
sagittal stir of ( a ) the cervico - thoracic and ( b ) the lumbar spine of the patients shown in fig .
there are multiple high signal intensity areas corresponding to vertebral corners ( white arrows ) .
additionally , osseous oedema of the costo - vertebral joints ( a , black arrows ) seen on the lateral sagittal slice of the thoracic spine .
( c ) axial post - contrast t1fs of an inflamed costo - vertebral joint confirmed the presence of joint inflammation in the form of osseous enhancement in both the vertebra and the rib ( arrows ) in addition to joint erosion .
( e ) inflammatory changes at the apophyseal joint in a 27-year - old man ; sagittal stir image of the lumbar region showing subchondral osseous oedema in the lower thoracic region ( white arrows ) , and both osseous and soft tissue oedema corresponding to the lumbar apophyseal joints ( black arrows ) .
note that the osseous oedema in the pedicle of th12 extends to the region of the costo - vertebral joint .
( f ) coronal post - contrast t1fs of the lumbar spine shows additional enhancement corresponding to the interspinous ligament between l2 and l3 ( arrows ) chronic as changes detectable by mri mainly consist of fatty marrow deposition at vertebral corners ( fig .
17 ) , erosion ( fig . 11 ) and vertebral fusion in advanced disease ( fig .
. fatty marrow deposition seems to be an important sign of chronicity being significantly correlated with radiographic changes , in particular vertebral squaring .
11 ) and can present with signs of active inflammation and/or surrounding fatty marrow deposition compatible with sequels of osseous inflammation .
syndesmophytes , however , may not always be visible by mri because they may be difficult to distinguish from fibrous tissue unless there is concomitant active inflammation or fatty deposition ( figs . 11 , 16 ) [ 15 , 20 ] .
sagittal t1 of ( a ) the cervico - thoracic and ( b ) the lumbar spine of the patients shown in fig .
there are multiple fatty marrow depositions at vertebral corners and also posteriorly in thoracic vertebral bodies ( b , arrows ) .
this was observed to have developed since the mri performed 3 years previously ( shown in fig .
16a - d ) and corresponds to areas of previous inflammation chronic changes in as by mri .
sagittal t1 of ( a ) the cervico - thoracic and ( b ) the lumbar spine of the patients shown in fig .
there are multiple fatty marrow depositions at vertebral corners and also posteriorly in thoracic vertebral bodies ( b , arrows ) .
this was observed to have developed since the mri performed 3 years previously ( shown in fig .
16a - d ) and corresponds to areas of previous inflammation the possibility of visualising disease activity by mri has increased its use to monitor as , especially during anti - tnf ( anti - tumour necrosis factor ) therapy [ 21 , 22 ] .
several studies have shown that mr changes are frequent in the thoracic spine ( fig .
it is therefore important to examine the entire spine using sagittal stir or t2 fat - saturated ( fs ) and t1-weighted sequences .
supplementary axial slices can be necessary for visualising involvement of apophyseal , costo - vertebral and costo - transversal joints ( fig .
post - contrast t1fs sequences can sometimes be advantageous as they provide better anatomical delineation .
additionally , dynamic contrast - enhanced mri may be superior to static mri in monitoring disease activity during anti - tnf therapy .
whole - body mri gives the possibility of detecting involvement in other areas without losing important information about spinal and sacroiliac joint involvement [ 28 , 29 ] .
radiographic changes in reactive and psoriatic arthritis are often characterised by voluminous non - marginal syndesmophytes ( parasyndesmophytes ) or coalescing ossification of the paravertebral ligaments in addition to asymmetrical sacroiliitis ( fig .
( a ) ap and ( b ) lateral radiograph of the lumbar spine in a 48-year - old man with psa showing voluminous paravertebral new bone formation ( arrows ) in addition to fusion of the second and third vertebral bodies .
( c ) ap radiograph of the thoraco - lumbar junction in a female patient with axial psa demonstrating coalescing paravertebral ossifications ( arrows ) psoriatic arthritis ( psa ) , paravertebral ossifications .
( a ) ap and ( b ) lateral radiograph of the lumbar spine in a 48-year - old man with psa showing voluminous paravertebral new bone formation ( arrows ) in addition to fusion of the second and third vertebral bodies .
( c ) ap radiograph of the thoraco - lumbar junction in a female patient with axial psa demonstrating coalescing paravertebral ossifications ( arrows ) reactive arthritis is self - limiting in most patients .
however , in patients with chronic reactive arthritis and hla b27 the axial changes may progress to changes somewhat similar to those seen in as and can then be regarded as as elicited by infection .
axial psoriatic arthritis ( psa ) occurs in approximately 50% of patients with peripheral psa .
it differs radiographically from as by the voluminous paravertebral ossifications and the occurrence of spinal changes without concomitant sacroiliitis in 10% of patients .
axial psa may be clinically silent , and involvement of the cervical spine is frequent ( atlanto - axial or apophyseal joint changes ) .
the cervical changes may include atlanto - axial instability as seen in ra ( fig .
19 ) , but the pathogenesis and thereby imaging findings are different . in psa radiography and ct
this is elicited by osseous inflammation ( osteitis ) and/or inflammation at ligament / tendon attachments ( enthesitis ) detectable by mri ( fig .
osteitis is often a feature of spinal psa and can occur together with paravertebral ossification / parasyndesmophytes and erosion of vertebral plates ( fig . 20 ) .
the above - mentioned and illustrated mr findings in psa are based on personal observations and seem to reflect the radiographic changes encompassing a mixture of osteitis , enthesitis and erosion . unfortunately , there is a lack of systematic description of spinal changes in psa by mri .
some of the patients described under the term sapho ( synovitis , acne , pustulosis , hyperostosis , osteitis ) syndrome may have psa .
sapho is a collective term often used for inflammatory disorders primarily presenting with osseous hyperostosis and sclerosis , and they are frequently associated with skin disorders .
the most commonly affected site in sapho is the anterior chest followed by the spine .
( a ) lateral radiographs in the neutral position and ( b ) during flexion in a 61-year - old woman show atlanto - axial instability with a 4-mm distance between the anterior arc and the dens ( white line ) .
additionally , ankylosis of the apophyseal joints ( black arrows ) and new bone formation anterior to the c4 - 7 vertebral bodies ( white arrows ) .
ct , ( c ) axial slice and coronal reconstruction of the dens area , demonstrates new bone formation in the atlanto - axial region ( arrows ) ; ( d ) coronal reconstruction of the lower cervical region shows voluminous new bone formation on the right side of the vertebral bodies ( arrows ) .
mri , ( e ) sagittal stir and ( f ) t1-weighted images , shows homogeneous osseous inflammation corresponding to the dens ( arrows ) with surrounding irregular oedema compatible with a mixture of osteitis and enthesitis .
note that the anterior new bone formation visualised by radiography is difficult to detect on mrifig .
( a ) ap and ( b ) lateral radiograph in a 50-year - old man show voluminous paravertebral ossifications anteriorly and at the right side of the third lumbar vertebra and adjacent iv spaces .
mri , ( c ) sagittal stir , ( d ) t1 and ( e ) post - contrast t1-weighted images , demonstrates manifest osseous inflammation ( osteitis ) in the form of oedema and enhancement of the vertebral body , slight enhancement in the paravertebral new bone formation and erosion of the upper vertebral plate compatible with a mixture of osteitis , enthesitis and erosive changes cervical psa .
( a ) lateral radiographs in the neutral position and ( b ) during flexion in a 61-year - old woman show atlanto - axial instability with a 4-mm distance between the anterior arc and the dens ( white line ) .
additionally , ankylosis of the apophyseal joints ( black arrows ) and new bone formation anterior to the c4 - 7 vertebral bodies ( white arrows ) .
ct , ( c ) axial slice and coronal reconstruction of the dens area , demonstrates new bone formation in the atlanto - axial region ( arrows ) ; ( d ) coronal reconstruction of the lower cervical region shows voluminous new bone formation on the right side of the vertebral bodies ( arrows ) .
mri , ( e ) sagittal stir and ( f ) t1-weighted images , shows homogeneous osseous inflammation corresponding to the dens ( arrows ) with surrounding irregular oedema compatible with a mixture of osteitis and enthesitis .
note that the anterior new bone formation visualised by radiography is difficult to detect on mri lumbar psa .
( a ) ap and ( b ) lateral radiograph in a 50-year - old man show voluminous paravertebral ossifications anteriorly and at the right side of the third lumbar vertebra and adjacent iv spaces .
mri , ( c ) sagittal stir , ( d ) t1 and ( e ) post - contrast t1-weighted images , demonstrates manifest osseous inflammation ( osteitis ) in the form of oedema and enhancement of the vertebral body , slight enhancement in the paravertebral new bone formation and erosion of the upper vertebral plate compatible with a mixture of osteitis , enthesitis and erosive changes in patients with enteropathic arthritis associated with crohn s disease or ulcerative colitis , the spine is often osteoporotic with various accompanying spa features by radiography , mostly as - like changes .
however , by mri there may be more pronounced inflammation in the posterior ligaments than seen in the other forms of spa ( fig .
sagittal stir image of the lumbar spine in a 27-year - old man with ulcerative colitis demonstrates oedema corresponding to the interspinous ligaments ( arrows ) and spinous processes as signs of inflammation .
there are only minimal activity changes corresponding to the vertebral bodies , located to the anterior vertebral corners enteropathic spa .
sagittal stir image of the lumbar spine in a 27-year - old man with ulcerative colitis demonstrates oedema corresponding to the interspinous ligaments ( arrows ) and spinous processes as signs of inflammation .
there are only minimal activity changes corresponding to the vertebral bodies , located to the anterior vertebral corners
however , mri and ct can detect signs of spinal involvement before they can be visualised by radiography .
mri adds information about potential involvement of the spinal cord and nervous roots in addition to signs of disease activity and chronic changes such as fibrous pannus in ra and fatty marrow deposition , erosion and vertebral fusion in spa .
mri is therefore widely used to monitor inflammatory spinal diseases , especially during anti - tnf therapy .
computed tomography is particularly valuable in the detection of fracture and minor osseous lesions as well as in the evaluation of pseudo - arthrosis .
Output:
| spinal involvement is frequent in rheumatoid arthritis ( ra ) and seronegative spondyloarthritides ( spa ) , and its diagnosis is important .
thus , mri and ct are increasingly used , although radiography is the recommended initial examination .
the purpose of this review is to present the typical radiographic features of spinal changes in ra and spa in addition to the advantages of mri and ct , respectively .
ra changes are usually located in the cervical spine and can result in serious joint instability .
subluxation is diagnosed by radiography , but supplementary mri and/or ct is always indicated to visualise the spinal cord and canal in patients with vertical subluxation , neck pain and/or neurological symptoms .
spa may involve all parts of the spine .
ankylosing spondylitis is the most frequent form of spa and has rather characteristic radiographic features . in early stages
it is characterised by vertebral squaring and condensation of vertebral corners , in later stages by slim ossifications between vertebral bodies , vertebral fusion , arthritis / ankylosis of apophyseal joints and ligamentous ossification causing spinal stiffness .
the imaging features of the other forms of spa can vary , but voluminous paravertebral ossifications often occur in psoriatic spa .
mri can detect signs of active inflammation as well as chronic structural changes ; ct is valuable for detecting fracture . |
PubmedSumm6504 | ***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 house dust mites ( hdm ) are major sources of indoor allergens for humans , which induce asthma , rhinitis , dermatitis , and other allergic diseases .
their major allergens ( dermatophagoides pteronyssinus [ der p ] and dermatophagoides farinae [ der f ] ) coexist in most geographical regions with a high proportion ( up to 85% ) of asthmatics being typically hdm allergic ; hence , sensitization is attributed as a risk factor for developing asthma .
recently , a birth cohort study showed that sensitization to hdm at age of 2 years was associated with current wheeze at age of 12 years in both monosensitized and polysensitized hdm - sensitized children . in previous studies , fourteen d. farinae allergens
( der f 13 , 6 , 7 , 10 , 11 , 1318 , and 22 ) were reported before other seventeen allergens belonging to twelve different groups were identified by a procedure of proteomics combined with two - dimensional immunoblotting from d. farinae extracts [ 3 , 4 ] . among the novel identified d. farinae allergens , der f 25 is a triosephosphate isomerase ( tpi ) with a molecular weight of 34 kda , showing 75.6% by immunoblotting and 60% by skin prick positive reaction to dust mite allergic patients , respectively .
tpi is an enzyme ( ec 5.3.1.1 ) that catalyzes the reversible interconversion of the triose phosphate isomers dihydroxyacetone phosphate and d - glyceraldehyde 3-phosphate .
it has been found in nearly every organism searched for the enzyme , including animals such as mammals and insects as well as in fungi , plants , and bacteria .
moreover , some tpis have been identified as an allergen in fish , midges , crustaceans , and various plants [ 612 ] . currently , specific immunotherapy is the only allergen - specific approach for its treatment of mite allergy .
the administration of increasing doses of allergen extracts to patients is the method most commonly applied .
. it could induce severe anaphylactic side reactions or lead to sensitization towards new allergens present in the mixture [ 13 , 14 ] .
different strategies have been designed to try to overcome these negative effects , as the use of allergen - derived b cell peptides , allergen - derived t cell epitope containing peptides , or vaccination with allergen - encoding dna . known
epitopes for some of these mite allergens are described in detail in cui 's review . however , there is no report about the epitope of der f 25 allergen . in the present study ,
we firstly identified the b and t cell epitopes of der f 25 allergen by in silico approach .
it implied their potential utility in a peptide - based vaccine design for mite allergy .
the complete amino acid sequence of der f 25 was acquired from the nucleotide database of ncbi ( http://www.ncbi.nlm.nih.gov/ ) with the accession number of kc305500.1 .
the amino acid sequence was also used as query to search for homologous sequences through the swiss - prot / trembl ( uniprot ) ( http://www.uniprot.org/ ) and tblastn in ncbi ( http://blast.ncbi.nlm.nih.gov/blast.cgi ) .
phylogenetic tree was obtained by using ml ( maximum - likelihood ) method on the basis of the jtt amino acid sequence distance implemented in mega 5.1 ; the reliability was evaluated by the bootstrap method with 1000 replications .
the possible domains and characteristic motifs and patterns contained in der f 25 were investigated by pfam v27.0 ( http://pfam.sanger.ac.uk/ ) , prosite ( http://prosite.expasy.org/scanprosite/ ) , interpro v46.0 ( http://www.ebi.ac.uk/interpro/ ) , and superfamily v1.75 ( http://supfam.cs.bris.ac.uk/superfamily/index.html ) .
physiochemical analysis including molecular weight , theoretical pi , amino acid composition , instability index , aliphatic index , and grand average of hydropathicity ( gravy ) of der f 25 was performed by using protparam tool ( http://web.expasy.org/protparam/ ) .
der f 25 characteristic pattern was checked for original sequence and further analysis was performed to highlight the presence of functional motifs by using the prosite database ( http://prosite.expasy.org/ ) . biologically meaningful motifs and susceptibility to posttranslational modifications
phosphorylation motifs with more than 80% of probability of occurrence were analyzed by using netphos v2.0 ( http://www.cbs.dtu.dk/services/netphos/ ) and netphosk v1.0 ( http://www.cbs.dtu.dk/services/netphosk/ ) .
der f 25 secondary structural elements were predicted by psipred ( http://bioinf.cs.ucl.ac.uk/psipred/ ) , which threads sequence segments through protein data bank ( pdb ) library ( http://www.rcsb.org/ ) to identify conserved substructures .
furthermore , the secondary structure elements were also identified with the result obtained with netsurfp ver .
as well , the homologous templates suitable for der f 25 were selected by psi - blast server ( http://blast.ncbi.nlm.nih.gov/blast.cgi ) and swiss - model server ( http://swissmodel.expasy.org/ ) [ 25 , 26 ] . the best template was retrieved from the results of previous methods and used for homology modeling .
der f 25 modeled protein structure was built through alignment mode in swiss - model using the complete amino acid sequence .
an initial structural model was generated and checked for recognition of errors in 3d structure by procheck , errat , and verify 3d programs in structural analysis and verification server ( saves ) ( http://nihserver.mbi.ucla.edu/saves/ ) .
the final model structure quality of der f 25 was assessed by qmean , by checking protein stereology with prosa program and the protein energy with anolea ( http://protein.bio.puc.cl/cardex/servers/anolea/ ) .
the ramachandran plot for all the models was generated , showing the majority of the protein residues in the favored regions .
der f 25 model was submitted to consurf server ( http://consurf.tau.ac.il/ ) in order to generate evolutionary related conservation scores helping to identify functional regions in the proteins .
functional and structural key residues in der f 25 sequence were confirmed by conseq server .
apbs molecular modeling software implemented in pymol 0.99 was used to investigate the electrostatic poisson - boltzmann ( pb ) potentials of der f 25 model structure .
amber99 in pdb2pqr server ( http://nbcr-222.ucsd.edu/pdb2pqr_1.8/ ) was used to assign the charges and radii to all of the atoms ( including hydrogens ) .
fine grid spaces of 0.35 were used to solve the linearized pb equation in sequential focusing multigrid calculations in a mesh of 130 points per dimension at 310.00 k. the dielectric constants were 2.0 and 80.0 for the protein and water .
the output mesh was processed in the scalar opendx format to render isocontours and maps onto the surfaces with pymol 0.99 .
potential values are given in units of kt per unit charge ( k boltzmann 's constant ; t temperature ) .
three immunoinformatics tools including dnastar protean system , bioinformatics predicted antigenic peptides ( bpap ) system ( http://imed.med.ucm.es/tools/antigenic.pl ) , and bepipred 1.0 server ( http://www.cbs.dtu.dk/services/bepipred/ ) were used to predicate the b cell epitopes of der f 25 .
the ultimate consensus epitope results were obtained by combining the results of the three tools together with the method published earlier . in the dnastar protean system , four properties ( hydrophilicity , flexibility , accessibility , and antigenicity ) of the amino acid sequence were chosen as parameters for epitopes prediction .
the bpap system and the bepipred 1.0 server only need the amino acid sequence and provide more straightforward results which are combined with physicochemical properties of amino acids such as hydrophilicity , flexibility , accessibility , turns , and exposed surface .
t cell epitopes are principally predicted indirectly by identifying the binding of peptide fragments to the mhc complexes .
the binding significance of each peptide to the given mhc molecule is based on the estimated strength of binding exhibited by a predicted nested core peptide at a set threshold level . for hla - dr - based t cell epitope prediction , the artificial neural network - based alignment ( nn - align ) method netmhciipan-3.0 ( http://www.cbs.dtu.dk/services/netmhciipan/ ) was applied . for hla - dq alleles , netmhcii-2.2 ( http://www.cbs.dtu.dk/services/netmhcii/ )
hla - dr 101 , hla - dr 301 , hla - dr 401 , and hla - dr 501 were used to predict hla - dr - based t cell epitope prediction .
the ultimate hla - dr - based t cell epitope results were obtained by combining those four results together that if three of them showed epitope , then the consensus result was epitope .
this method was also used in hla - dq - based t cell epitope prediction .
hla - dqa10101-dqb10501 , hla - dqa10501-dqb10201 , hla - dqa10501-dqb10301 , and hla - dqa10102-dqb10602 were used to predict hla - dq - based t cell epitope prediction . as a result
, the ultimate consensus epitope results were obtained by combining the results of the hla - dr - based t cell epitope and hla - dq - based t cell epitope .
b cell and t cell epitopes identified by computational tools were mapped onto linear sequence and on the three - dimensional model of der f 25 to determine their position and secondary structure elements involved .
the amino acid sequence of der f 25 was obtained from the nucleotide database of ncbi .
uniprot and tblastn were used to search the homologous sequences of der f 25 . as a result ,
thirty - six sequences were obtained and in order to determine the relationships between der f 25 and its homologous sequences , phylogenetic analysis was performed and the evolutionary tree inferred by the ml method was showed in figure 1 .
phylogenetic analysis result showed that there are proteins including der f 25 clustered into the same group , belonging to tips .
moreover , domain analysis results showed that der f 25 belongs to the tim phosphate binding superfamily ( superfamily number ssf51351 and interpro number ipr016040 ) and tpi family ( superfamily number ssf51352 and interpro number ipr000652 ) . after searching for characteristic motifs or patterns
, we found that der f 25 exhibited a tpi pattern , ps00171 ( 162172 , ayepvwaigtg ) ( figure 2 ) .
phosphorylation sites including two ser ( 95 and 221 ) and two thr ( 146 and 171 ) residues were predicted and showed in figure 2 .
two types of kinases ( pkc for 95 , 146 , and 171 and dnapk for 221 ) were predicted to be phosphorylated for der f 25 complete sequence .
the primary structure of der f 25 contained 247 amino acids and the molecular weight is 27134.1 .
the theoretical pi is 6.24 and the aliphatic index is 95.06 . the gravy is 0.103 meaning that der f 25 exhibited hydrophilic character .
the instability index is 30.57 meaning that the sequence of der f 25 is stable .
searching for the proteins with known tertiary structure in the pdb yielded tenebrio molitor tpi ( pdb accession number : 2i9e ) showing the highest sequence identity ( 74% ) with der f 25 .
the swiss - model server was also used to identify the best possible template and found a high score of 365 and very low e - value of e-101 for 2i9e template .
hence , the 2i9e template was used for homology modeling . as indicated by the ramachandran plot ( figure 3(b ) ) , 93% residues in der f 25 model were within the most favored regions , 7% residues in the additional allowed region , 0% residues in the generously allowed regions , and 0% residues in the disallowed region ; 93.4% residues in 2i9e template were within the most favored regions , 6.6% residues in the additional allowed region , 0% residues in the generously allowed regions , and 0% residues in the disallowed region . the goodness factor ( g - factor ) based on the observed distribution of stereochemical parameters ( main chain bond angles , bond length , and phi - psi torsion angles ) returned accurate values for a reliable model ( table 1 ) , in comparison with the template 2i9e ( table 1 ) .
as indicated by the errat program , the result showed that the overall quality factor is 97.034 for der f 25 and 97.789 for 2i9e meaning that both of the two structures have good high resolution .
as indicated by the verify 3d program , the result showed that 99.6% and 99.8% of der f 25 and 2i9e template residues had an average 3d ( atomic model)-1d ( amino acid sequence ) score > 0.2 also meaning that those two structures were good .
prosa analysis returned z - scores of 10.1 and 10.24 for der f 25 and 2i9e ( table 1 ) , respectively .
q values for der f 25 and 2i9e structures are 0.772 and 0.798 , respectively .
root mean square deviations ( rmsd ) between der f 25 structural model and 2i9e template c backbone are 0.062 ( table 1 ) . based on these validations
secondary structure prediction of der f 25 with psipred identified ten -helices and seven -sheets ( figure 2 ) in der f 25 .
the best template 2i9e was used for homology modeling ; the overall 3d structure of der f 25 was shown in figure 3(a ) .
sequence polymorphism was responsible for the changes in the spatial distribution of the skeleton alpha carbons , which is reflected in differences between the structures of der f 25 and 2i9e .
a superposition of the der f 25 with the 2i9e template is shown in figure 3(b ) and the values for superimposed c are 0.062 . as a tpi protein , der f 25 has two active sites ; his in the 94th position is an electrophile while glu in the 164th position is the proton acceptor .
it has two substrate binding sites , the asn in the 10th position and the lys in the 12th position .
moreover , the characteristic pattern predicted by scanprosite tool is shown in figure 3(c ) .
consurf conservational analysis of structural and functional key amino acids showed that the der f 25 protein surfaces were not well conserved , with almost forty high variability residues in different superficial areas .
surface electrostatic potential analysis reveals several prominent charged residues , with half of the side exhibiting large positive values ( blue regions ) and the other half showing predominantly negative values ( red regions ) ( figure 3(d ) ) .
in addition , the existence of regions with high hydrophobicity also provides strong evidence for epitope identification .
based on these sequence properties , the final predicting regions of dnastar were 1119 , 2835 , 6877 , 95111 , 130139 , 173187 , 193197 , and 211225 . also , the predicted results of the bpap system were 2026 , 3252 , 5470 , 8693 , 138168 , 175209 , and 218242 and bepipred 1.0 server were 1118 , 3034 , 7178 , 99107 , 132138 , 168183 , 194199 , and 210224 .
furthermore , the final potential b cell epitopes of der f 25 were selected on the basis of the results of these three tools .
the ultimate results of the three immunoinformatics tools finally predicted eight peptides ( 1118 , 3035 , 7177 , 99107 , 132138 , 173187 , 193197 , and 211224 ) ( table 2 ) and these peptides were also shown in figures 2 and 4 .
netmhciipan-3.0 and netmhcii-2.2 were used to identify the t cell epitope of der f 25 . for hla - dr - based t cell epitope prediction ,
the final predicting regions of hla - dr 101 , hla - dr 301 , hla - dr 401 , and hla - dr 501 were shown in table 1 and the ultimate results of hla - dr - based t cell epitope prediction finally predicted five peptides ( 2634 , 3854 , 6674 , 142151 , and 239247 ) .
for hla - dq alleles , the final results of hla - dqa10101-dqb10501 , hla - dqa10501-dqb10201 , hla - dqa10501-dqb10301 , and hla - dqa10102-dqb10602 were also shown in table 3 and the ultimate results of these four methods finally predicted one peptide , 3948 . as a result , der f 25 was predicted to have five t cell epitope sequences including 2634 , 3854 , 6674 , 142151 , and 239247 ( table 2 ) as shown in figures 2 and 4 .
the prevalence of human atopic disorders including allergic rhinitis , asthma , and atopic dermatitis is increasing during the past several decades .
house dust mite allergies constitute more than 50% of allergic patients and often have severe forms of respiratory allergy , such as asthma .
characterization of mite allergens will be beneficial in the diagnosis and treatment of mite - induced atopic illnesses . among the identified allergens ,
der f 25 is a new protein with a molecular weight of 34 kda , representing the major allergen in d. farinae .
the objective of this study was to predict the b and t cell epitopes of der f 25 .
firstly , in order to better understand the structure and function of der f 25 , we analyzed the basic sequence properties and studied the 2d and 3d structures of der f 25 .
phylogenetic analysis result showed that der f 25 protein clustered into the tips group ; domain analysis also proved a strong evidence illustrating that der f 25 belongs to the tpi family . in 2d structure analysis
, it is clearly shown that der f 25 composed of ten -helices and seven -sheets .
the 3d structure of der f 25 was performed by homology modelling which was widely used in many areas of structure - based analysis and study .
pdb server was used to search templates of der f 25 and found that the structure of tenebrio molitor tpi ( 2i9e ) was the best template with the highest identity . also , small dissimilates in rmsd were observed between der f 25 and 2i9e template .
the built model structure is feasible by the ramachandran plot analysis , errat program , verify 3d program prosa analysis , q values , and rmsd .
the similar methods for the structures modelling were also successfully conducted in other allergens of api si and api sii , der f 5 , ole e 2 ole e 11 , and ole e 12 .
based on the conservational analysis of the primary sequence of der f 25 , it is found that almost forty high variability residues sit in different superficial areas of protein surface .
the active sites his in 94th position and glu in 164th position as well as the substrate binding sites asn in 10th position and lys in 12th position are the completely conserved sites .
in silico prediction has already become a familiar and useful tool for selecting epitopes from immunological relevant proteins , which can save the expense of synthetic peptides and the working time .
recently , many algorithms have been developed to predict b cell epitopes on a protein sequence based on propensity values of amino acid properties of hydrophilicity , antigenicity , segmental mobility , flexibility , and accessibility . in the present study , we used three algorithms ( dnastar protean system , bpap , and
the previous study showed that the use of bioinformatics approach to predict b cell epitopes correlated well with the experimental approach .
earlier study showed that allergen epitopes were comprised of a high proportion of hydrophobic amino acids .
the amino acids ala , ser , asn , gly , and particularly lys play a key role in the ige binding allergenic epitopes . in our results ,
nearly half of the total residues lying in b cell epitopes were hydrophobic ( table 2 ) .
moreover , each predicted b cell epitope has one or more special five amino acids and the common residues in all b cell epitopes were gly and lys ( table 2 ) .
electrostatic interactions are known to determine the orientation of the molecules and stabilize antigen - antibody complexes .
surface electrostatic potential analysis result showed that a great part of der f 25 side exhibits large positive values ( blue regions ) .
most parts of b cell epitopes are distributed in the blue regions and showed a strong negative potential . as a result ,
eight peptides ( 1118 , 3035 , 7177 , 99107 , 132138 , 173187 , 193197 , and 211224 ) were predicted as the b cell epitopes .
however , these b cell epitopes need further investigation in clinical samples . in the last several years
, some methods have substantially improved their accuracy to predict t cell epitopes such as netmhcpan-3.0 and netmhcii-2.2 .
netmhcpan-3.0 is based on artificial neural networks and is trained on 52,062 quantitative peptide binding data covering all hla as well as two mouse molecules . in this study , it was used to predict the hla - dr - based t cell epitopes . for hla - dq - based t cell epitopes prediction ,
although limited binding - affinity data are available for hla - dq , it was recently reported to provide the best performance in predicting this locus . as a result , netmhciipan-3.0 and netmhcii-2.2
were used to predict the t cell epitopes in der f 25 allergens and predicted 7 potential t cell epitope sequences including 2634 , 3854 , 6674 , 142151 , and 239247 . despite the high accuracy of these predictions , this approach has not yet been applied to peptide - based vaccine development for allergic diseases .
allergen - specific immunotherapy ( sit ) represents the only allergen - specific and disease - modifying approach with long lasting effects for the treatment of allergic patients .
however , sit can induce side effects , ranging from mild and local to severe and life - threatening symptoms , such as anaphylactic shock .
severe side effects are frequently observed in patients with house dust mite ( hdm ) allergy . the continuous exposure to hdm
allergens further complicates the treatment of patients with hdm allergy . additionally , the quality of natural hdm allergen extracts and vaccines based on these extracts is often poor .
attenuated allergenic molecules , that is , hypoallergens or synthetic peptide fragments , have been used as high dose and safer alternatives to conventional extract - based sit .
vaccination with a combination of small peptides that together extend across the entire native allergenic protein theoretically could preserve t cell activation while avoiding ige - based immune responses .
ige recognizes conformational epitopes of larger peptides ( b cell epitopes ) and proteins while t cell receptors recognize small linear peptides of 8 to 10 amino acids ( t cell epitope ) . by immunizing with small peptides ,
t cell activation could occur while ige binding would be lost [ 55 , 56 ] .
then , we predicted b and t cell epitopes of der f 25 allergen , the major allergen in hdm , using in silico method which can be used to benefit allergen immunotherapies and reduce the frequency of allergic reactions .
in this study , we have a better understanding of the 2d and 3d structures of der f 25 and have predicted eight b cell epitopes ( 1118 , 3035 , 7177 , 99107 , 132138 , 173187 , 193197 , and 211224 ) and five t cell epitope including 2634 , 3854 , 6674 , 142151 , and 239247 of this tpi .
all these results can be used to benefit allergen immunotherapies and reduce the frequency of mite allergic reactions .
Output:
| the house dust mites are major sources of indoor allergens for humans , which induce asthma , rhinitis , dermatitis , and other allergic diseases .
der f 25 is a triosephosphate isomerase , representing the major allergen identified in dermatophagoides farinae .
the objective of this study was to predict the b and t cell epitopes of der f 25 . in the present study
, we analyzed the physiochemical properties , function motifs and domains , and structural - based detailed features of der f 25 and predicted the b cell linear epitopes of der f 25 by dnastar protean system , bpap , and bepipred 1.0 server and the t cell epitopes by netmhciipan-3.0 and netmhcii-2.2 . as a result , the sequence and structure analysis identified that der f 25 belongs to the triosephosphate isomerase family and exhibited a triosephosphate isomerase pattern ( ps001371 ) .
eight b cell epitopes ( 1118 , 3035 , 7177 , 99107 , 132138 , 173187 , 193197 , and 211224 ) and five t cell epitopes including 2634 , 3854 , 6674 , 142151 , and 239247 were predicted in this study . these results can be used to benefit allergen immunotherapies and reduce the frequency of mite allergic reactions . |
PubmedSumm6505 | ***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: takayasu arteritis ( ta ) , also known as aortoarteritis and pulseless disease , is a rare condition .
it is a form of granulomatous arteritis , which affects large- and medium - sized arteries , primarily the aorta and its large branches as well as proximal portions of pulmonary , coronary , and renal arteries .
initially , there are mononuclear cell infiltrations in the adventitia and granulomas with langerhans cells in the media , followed by disruption of the elastin layer and subsequent massive medial and intimal fibrosis
. these lesions result in segmental stenosis , occlusion , dilatation , and aneurysmal formation in the affected vessels .
ta is predominantly a disease of young adults in the second and third decades of life , but it has also been reported in childhood and in adults older than 40 years [ 20 , 28 , 44 ] .
the youngest patient described was 6 months old , and the oldest one was 75 years .
females are more likely to be affected than males . in adults approximately 80% of patients with ta
are women , although the female - to - male ratio varied from 9:1 in reports from japan , 6.9:1 in mexico to 1.2:1 in israel . in the pediatric population ,
a series of studies of ta in childhood from india and south africa report a 2:1 female - to - male ratio [ 16 , 46 ] .
although the disease has a worldwide distribution , the incidence is considered to be substantially greater in regions such as india and east asia than europe or north america . unfortunately , there are no worthwhile epidemiological studies from these supposedly high incidence countries to support this assertion . according to the published reports ,
the worldwide incidence of ta is estimated at 2.6 cases per million population per year .
the incidence of ta is estimated to be 2.6 persons per million population per year in minnesota olmsted county . however , the applicability of this number to the diverse population of the usa as a whole is uncertain .
the incidence in europe overall is reported at one case per million persons per year . in sweden
, the annual incidence is 1.2 per million , whereas in the united kingdom it is 0.15 case per million per year .
kerr et al . included about 30% of pediatric patients in their study and reported an incidence in all ages of 2.6 per million .
although patients with takayasu arteritis may present with numerous clinical manifestations , arterial hypertension is the most common feature of the disease in both adults and children [ 10 , 16 , 17 , 24 , 46 ] .
a 16-year - old caucasian girl was referred to our hospital due to elevated arterial blood pressure , which was detected by chance . upon admission ,
her body weight and height were 49 kg ( the10th percentile ) and 161 cm ( the 25th percentile ) , respectively , with a bmi of 18/kg / m .
however , weakness and fatigability of the upper left extremity were disclosed by a detailed history .
in addition , we found out that 2 years earlier , difficulties in measurement of blood pressure on her left arm had occurred .
her family history was unremarkable . on physical examination , there was no evidence of heart failure .
vascular bruits over the interscapular and right supra- and the subclavian areas were heard on auscultation .
the muscles of the upper left extremity were slightly atrophic , and their tone was decreased .
the pulse of the left external carotid artery and that of the left radial artery was absent .
the femoral pulses were present and equal . on admission , a significantly elevated systolic blood pressure 192/77 mmhg on the right arm was observed ( systolic blood pressure above 95th percentile for patient s age , gender , and height , and normal diastolic blood pressure ) , whereas the measurement of blood pressure on the left arm was difficult but was about 90/52 mmhg .
the blood pressure on right and left legs was 137/74 and 134/70 mmhg , respectively .
laboratory findings showed an elevated erythrocyte sedimentation rate ( esr ) of 46 mm / h ( normal value < 20 mm/1 h ) and serum c - reactive protein level of 1.13 mg / dl ( normal value < 0.5 mg / dl ) .
the rest of the laboratory investigations , including serum creatinine , electrolytes , autoantibodies , and urinalysis , were normal , as well as the ecg and chest x - ray .
on echocardiography , except for small mitral valve regurgitation , intracardiac anatomy abnormalities were not observed .
the left ventricular walls were not hypertrophied , the left ventricular internal diastolic dimension was 47.5 mm and remained within the normal range for the patients age and weight ( 37.554.7 mm ) .
dilatation of the ascending aorta and stenosis of the descending aorta were visible but without a significant poststenotic increase in blood flow velocity .
no prograde blood flow was observed in the left common carotid and in the left subclavian arteries .
1 and 2 ) showed a thickened thoracic aortic wall ( 2.74.5 mm ) and narrowing of its lumen .
the aortic measurements and z score date , according to kaiser et al . , were performed as presented in table 1 . on the basis of clinical manifestations and angiographic abnormalities ,
1spiral computed tomography angiography examination , cross - section slices presenting circumferential thickening of aortic wall . a level of aao and dao with slightly thickened wall of proximal section of pulmonary trunk ; b level of aortic arch with nonenhanced l ita ; c proximal sections of aortic arch branches with occluded l cca and l sca ; d widening of r va , lack of opacification of l va and l cca ( marked with arrows ) .
aao ascending aorta , aa aortic arch , dao descending aorta , bct brachiocephalic trunk , cca common carotid artery ( l left , r right ) , sca subclavian artery ( l left , r right ) , va vertebral artery ( l left , r right ) , ita internal thoracic artery ( l left , r right ) , pt pulmonary trunkfig . 2scta examination
thickened aortic wall with slightly narrowed lumen of dao ; b volumetric reconstruction view of branches of aortic arch with occluded l cca and l sca marked with arrowstable 1the results of scta examinationsites of measurementdiameter ( mm)z score ascending aorta293.87 first transverse segment20 second transverse segment19 the isthmic region141.87 the minimal diameter of the descending aorta84.77 ( below 3 percentile)abnormalities smooth external outline of the aorta , irregular internal outline , and laminar calcification in the ascending aorta wall thickened walls of brachiocephalic trunk , right common carotid artery proximal portion ( about 7 cm in length ) , and right subclavian artery proximal portion ( about 1 cm in length ) with narrowed lumina complete occlusion of the left common carotid artery and the left subclavian artery collateral circulation on the thoracic wall and parathyroid vessels slight thickening of the pulmonary trunk wall normal abdominal aorta and renal arteriesmeasurements and observed abnormalities spiral computed tomography angiography examination , cross - section slices presenting circumferential thickening of aortic wall .
a level of aao and dao with slightly thickened wall of proximal section of pulmonary trunk ; b level of aortic arch with nonenhanced l ita ; c proximal sections of aortic arch branches with occluded l cca and l sca ; d widening of r va , lack of opacification of l va and l cca ( marked with arrows ) .
aao ascending aorta , aa aortic arch , dao descending aorta , bct brachiocephalic trunk , cca common carotid artery ( l left , r right ) , sca subclavian artery ( l left , r right ) , va vertebral artery ( l left , r right ) , ita internal thoracic artery ( l left , r right ) , pt pulmonary trunk scta examination
thickened aortic wall with slightly narrowed lumen of dao ; b volumetric reconstruction view of branches of aortic arch with occluded l cca and l sca marked with arrows the results of scta examination measurements and observed abnormalities treatment with prednisone in the initial dose of 60 mg / day ( 1.3 mg / kg ) was introduced together with given orally methotrexate in a dose of 20 mg / m / week .
hypertension was treated using three medications namely : amlodipine ( 10 mg / day ) , hydrochlorothiazide ( 12.5 mg twice a day ) , and carvedilol ( 6.25 mg twice a day ) .
after 3 months , the dose of prednisone was gradually tapered to 10 mg / day .
initially the hypertension was not well controlled , so the option of stenting of the descending thoracic aorta had also been considered .
but due to the fact that nonspecific markers of inflammation were elevated and this girl had never been treated before , she was qualified for continued medical treatment . at present , under treatment , her blood pressure on the right arm varies between 123/70 and 140/96 mmhg and there is no pressure difference between her right arm and legs . in laboratory tests ,
c - reactive protein is only slightly elevated 0.67 mg / dl , esr is 17 mm / h .
moreover , an scta examination after a couple of months revealed a similar range of inflammatory changes within the aorta but the thickness of the infiltration had been reduced .
the patient is currently under a long - term clinical surveillance by a cardiologist , rheumatologist , nephrologist , and psychologist .
although our knowledge of ta has considerably improved over the last decade , the etiology and pathogenesis of this disease still remain controversial .
several etiologic factors have been proposed , including spirochetes , mycobacterium tuberculosis , streptococci , circulating antibodies due to an autoimmune process , and genetic aspects .
one hypothesis states that an antigen deposited in vascular walls activates cd4 + t cells , followed by the release of cytokines chemotactic for monocytes .
these monocytes are transformed into macrophages that mediate endothelial damage and granuloma formation in the vessel wall .
human studies , suggesting endothelial cell activation , have demonstrated increased expression of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 in patients with ta .
antimonocyte antibodies and anti - endothelial cell antibodies are present in patients with ta and correlate with disease activity .
genetic susceptibility to ta has been extensively studied . a significant association with hla b-52 and dr-2
was demonstrated in japanese patients , but this finding was not confirmed in the western countries [ 28 , 39 ] . rarely has ta also been associated with other autoimmune diseases such as glomerulonephritis , systemic lupus erythematosus , juvenile idiopathic arthritis , anterior uveitis , sarcoidosis , seronegative spondyloarthropathy , crohn s disease , wegener s granulomatosis , sweet syndrome , and ulcerative colitis , which may indicate immune mechanisms in the pathogenesis [ 1 , 6 , 9 , 18 , 33 , 34 , 40 , 43 , 51 ] .
considering arterial lesion location , on the basis of angiographic findings , ta is divided into six types ( table 2).table 2angiography - based categoriestypethe vessels involvedtype ibranches of the aortic archtype iiaascending aorta , aortic arch , and its branchestype iibtype iia region and thoracic descending aortatype iiithoracic descending aorta , abdominal aorta , and/or renal arteriestype ivabdominal aorta and/or renal arteriestype ventire aorta and its branches angiography - based categories there are some differences in the sites affected by inflammatory process among different ethnic groups .
japanese patients with ta have a higher incidence of aortic arch involvement , whereas in patients from korea , india , and western countries , the abdominal aorta and renal arteries are most frequently affected .
the clinical course of the disease is divided into an early active inflammatory phase and late chronic phase .
the active phase lasts for weeks to months and may have a remitting and relapsing course .
it is characterized by systemic disease with symptoms of fever , general malaise , night sweats , loss of appetite , weight loss , headaches , dizziness , arthralgia , skin rashes , etc .
the acute phase does not occur in all patients , but constitutional symptoms are often seen in children with ta .
it should be highlighted that the correct diagnosis of ta is seldom made in the early phase .
evidence of vessel inflammation such as tenderness along arteries , bruits , and aneurysm may point to the diagnosis of ta .
the late chronic phase is the result of arterial stenosis and/or occlusion and ischemia of organs .
its clinical manifestations are varied and related to the location of arterial lesions [ 28 , 39 ] , as presented in table 3.table 3clinical features of takayasu arteritis related to ischemiathe vessels involvedclinical features1 .
aortic branchesmalaise , decreased or absent pulse of upper extremities , dysfunction of upper extremities , headaches , dizziness , vision and orientation disturbances , syncope [ 25 , 48]2 .
aortic archcongestive heart failure , aortic valve insufficiency , arterial hypertension [ 13 , 14 , 29]3 . coronary arteriesischemic heart disease , myocardial infarction [ 4 , 11]4 .
abdominal aorta or celiac trunkischemia of the stomach and intestines , abdominal pain , nausea , vomiting 6 .
renal arteriesarterial hypertension , chronic renal failure [ 5 , 7 , 15 ] clinical features of takayasu arteritis related to ischemia it should be remembered that , although ta has been described in patients of all races , reports of caucasian patients in europe are infrequent .
therefore , key data concerning the condition , both in adults and in children , come from experience in asian as well as south african and south american countries . at present
, ta in children is diagnosed on the basis of the criteria proposed by european league against rheumatism
pediatric rheumatology international trials organization pediatric rheumatology european society , ankara 2008 , presented in table 4.table 4the diagnostic criteria for takayasu arteritis in childrenthe mandatory criterion the presence of an angiographic abnormality , i.e. , aneurysm / dilatation , narrowing , occlusion or thickened arterial wall not due to fibromuscular dysplasia and shown by conventional angiography , spiral computed tomography angiography or mra of the aorta or its main branches and pulmonary arteriesin addition to the mandatory criterion , at least one of the five following criteria must be met : pulse deficit ( lost , decreased , unequal ) or claudication ( focal muscle pain induced by physical activity ) discrepancy of four limb systolic blood pressure > 10 mmhg difference in any limb audible vascular bruits or palpable thrills over large arteries arterial hypertension ( systolic and/or diastolic blood pressure greater than 95th centile for patient s age , gender , and height ) elevation of acute phase reactant ( erythrocyte sedimentation rate > 20 mm per first hour or serum c - reactive protein of any value above normal according to the local laboratory ) the diagnostic criteria for takayasu arteritis in children in our patient , all the above - mentioned criteria were met . on the basis of the scta examination , ta of type iib , with pulmonary trunk involvement , was recognized . in our patient case ,
the onset of her disease was undetectable , and severe systolic arterial hypertension , which was revealed accidentally , was the predominant clinical manifestation .
pathogenesis of arterial hypertension due to ta is complex , multifactorial , and not fully understood . at present , it is thought to be the result of three mechanisms : ( a ) mechanical , in which hypertension proximal to narrowed aorta(atypical coarctation ) is due to high resistance to cardiac output imposed by narrowing ; ( b ) neural , in which hypertension proximal to narrowed aorta results from aortic arch baroreceptors readjustment and this allows to ensure adequate blood supply to organs distal to narrowed aorta ; and ( c ) hormonal , in which hypertension is caused by renal hypoperfusion due to stenotic lesions of one or both renal arteries or aorta alone [ 12 , 39 ] . a decrease in elasticity of arterial walls observed in ta may also contribute to the elevation of the blood pressure . in our patient
, systolic arterial hypertension seemed to result from narrowing of thoracic aorta , renal ischemia , and probably aortic arch baroreceptors hyposensitivity .
it should be emphasized that in ta , blood pressure may be over- or underestimated because alternation in wave pulse propagation occurs when cephalad arteries of the aortic arch and both subclavian arteries are affected .
the clinical spectrum at presentation of children with takayasu arteritis differs from that of adults . however , hypertension is the most common sign in both groups .
the clinical studies in three large series of pediatric cases from mexico , india , and south africa have revealed that systemic symptoms are seen in a high proportion of children with ta .
the usual presenting symptoms are due to hypertension , heart failure , or a neurological event .
claudication , bruit , and a missing pulse in an asymptomatic child are uncommon presentations , although those symptoms were present in our patient and they were crucial for establishing the diagnosis .
while the intra - arterial angiography still remains the standard for diagnosis and evaluation of takayasu arteritis , it has been largely replaced by computed tomography angiography or magnetic resonance angiography ( mra ) .
these techniques , in addition to visualizing the arterial lumen , may provide valuable information about inflammation in the arterial wall and periarterial structures .
this might facilitate the diagnosis of ta at an early stage , in which arterial wall thickening is present and the lumen diameter is preserved [ 3 , 42 ] .
the other investigative modalities , such as gallium-67 radionuclide scanning and positron emission tomography utilizing 18f - fdg , are currently in vogue when evaluating such patients [ 8 , 31 ] , although they are not widely available yet .
it should be emphasized that despite the significant advance in noninvasive imaging modalities over past decade , detailed medical history and thorough physical examination still remain important for clinical diagnosis .
treatment of ta is based on the use of immunosuppressants such as prednisone and/or methotrexate to decrease or eliminate inflammatory activity .
alternative therapies such as azathioprine , cyclophosphamide , mycophenolate mofetil , and tacrolimus hydrate are also used in ta , especially for corticosteroid - resistant disease [ 8 , 20 , 28 , 39 ] .
hypertension should be treated aggressively often with multidrug regimen , but pediatricians should be warned against ace inhibitors until renal artery stenosis has been excluded . in the presence of symptomatic stenotic or occlusive lesions ,
endovascular revascularization procedures like bypass grafts , patch angioplasty , endarterectomy , percutaneous transluminal angioplasty , or stent placement should be taken into consideration [ 15 , 49 , 50 ] .
the status of such treatment is controversial in the literature . despite providing short - term benefit , endovascular revascularization procedures
published results suggest that these procedures should be undertaken with great care and be reserved for specific indications .
both , surgical and endovascular , treatments become risky and achieve poorer outcomes , if they are undertaken during a period of inflammatory activity [ 31 , 36 , 47 ] .
the 5-year survival rate in adults is as high as 94% . the mortality rate in children ,
increasing knowledge of the pathogenesis of takayasu arteritis might eventually lead to novel - targeted therapies , such as antitumor necrosis factor agents .
although early diagnosis holds the key to improved outcome , a novel biological approach to treatment might prove more effective and be potentially less toxic than the immunosuppressive regiments used at present [ 31 , 38 ] .
Output:
| we report a 16-year - old girl in whom takayasu arteritis ( ta ) was manifested mainly by severe arterial hypertension on her right arm , which was detected during a routine examination at school .
her systolic blood pressure on the right arm was significantly higher than that on the left one .
there was also a pressure difference between the right arm and legs .
the pulse of the left external carotid artery and that of the left radial artery was absent .
vascular bruits over interscapular and right supra- and subclavian areas were heard on auscultation .
the diagnosis of ta was confirmed by a spiral computed tomography angiography , which showed a thickened thoracic aortic wall and narrowing of its lumen .
in addition , complete occlusion of the left common carotid artery and the left subclavian artery was observed .
conclusion : the rarity of the disorder and the heterogeneous nature of its clinical manifestation predispose to a late diagnosis and delayed treatment .
our report highlights the fact that the condition can and does occur in a pediatric population in europe and hence must be considered in patients presenting with suggestive symptoms and signs , especially in young patients with unexplained hypertension . clinical suspicion and proper imaging
are crucial for the correct diagnosis and management of patients with ta .
a brief review of literature completes this report . |
PubmedSumm6506 | ***TASK***
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the input is a biomedical literature
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Input: a 57-year - old patient with a diagnosis of chronic itp for 1 year was referred to our emergency department with complaints of left flank pain and diffuse petechial bleeding all over his body .
a complete blood count revealed thrombocytopenia ( 4,000/mm ) , which led to his admission into the clinics of internal medicine . on the third day of chronic itp therapy ,
the patient developed macroscopic hematuria , and we consulted with the patient after the urinary system ultrasound revealed bilateral perirenal hematoma .
we learned from his medical history that he had not previously had any complaints of gross hematuria .
he had previously undergone extracorporeal shock wave lithotripsy ( eswl ) because of a left ureteral distal stone .
the physical examination revealed a relaxed abdominal region with left costovertebral angle tenderness in addition to diffuse petechiae all over his body . in his biochemical analysis , blood urea nitrogen
( 53 mg / dl ) , creatinine ( 3.2 mg / dl ) , and fasting blood sugar ( 167 mg / dl ) levels were also measured .
escherichia coli was detected in the urine culture , and the urinalysis revealed microscopic hematuria and pyuria .
the results of the complete blood count analysis were as follows : white blood cells 27,000/mm , hemoglobin 12.2 g / dl , hematocrit 37.3% , platelet count 4,000/mm , prothrombin time 16.6 seconds ( 9 to 14 ) , and international normalized ratio 1.36 ( 0.8 to 1.19 ) .
owing to suddenly evolving macroscopic hematuria , the patient received prednisolone ( 80 mg / d ) and intravenous immune globulin ( 0.5 g / kg / d ) ( kiovig 10 g/100 ml - eczacba - baxter ) , and an ultrasound examination of the urinary system demonstrated right and left perirenal hematoma and irregular renal contours . a non - contrast computed tomography ( ct )
the ct scan revealed a right perirenal hematoma with dimensions of 212042 mm , a 15-mm stone in the right distal ureter without any marked ectasia , a left perirenal hematoma with dimensions of 15012090 mm ( fig .
1 ) , left distal ureteral ectasia , and a 20-mm distal ureteral stone ( fig .
the patient had an extremely low hematocrit ( 22% ) , hemoglobin ( 7.2 g / dl ) , and platelet counts ( 3,000/mm ) and received 6 iu erythrocytes and 3 iu platelets to improve his hematologic status .
an operation was performed for his distal ureteral stones when his platelet counts reached 89,000/mm .
there was no increase in the size of the hematoma , and regression was even shown on the postoperative control ct scan ( fig .
4 ) , and his blood urea nitrogen was 25 mg / dl and his creatinine was 0.79 mg / dl after 1 year .
chronic itp is an acquired bleeding diathesis with an immune origin . the onset and clinical course of the disease show variations .
mild and moderately severe forms of itp are asymptomatic in the absence of trauma , whereas in severe cases of itp , clinical manifestations consist mostly of mucocutaneous bleeding such as purpura , petechiae , nosebleeds , and gingival bleedings .
gastrointestinal bleeding , hematuria , and intracranial hemorrhages are relatively more severe conditions and occasionally fatal [ 1 - 3,6,7 ] . in a meta - analysis conducted by cohen et al . in 1,817 patients ,
the rate of age - adjusted fatal hemorrhage risk for patients who were younger than 40 years , between 40 and 60 years , and older than 60 years was 0.004 , 0.012 , and 0.130 , respectively .
spontaneous perirenal and subcapsular renal bleeding are rarely seen clinical manifestations that lead to serious problems .
are chronic hemodialysis , vascular pathologies such as atherosclerosis and arteritis , anticoagulant therapy , and hemorrhagic diathesis [ 2,4 - 9 ] . because the clinical course of the disease in patients with perirenal hematoma varies according to the severity of bleeding , the therapeutic approach is closely related to the clinical condition of the patient . in cases of persistent bleeding and a worsening general health state , surgical treatment predominates , whereas in patients with stable vital parameters , palliative treatment can be performed .
none of the very rarely encountered cases of renal bleeding due to itp reported mortality . in two cases we found during a literature search , bedrest ,
steroid therapy , and platelet suspensions were sufficient without the need for surgical management . according to the guidelines of the american hematologic association
, hospitalization is required for patients with mucocutaneous bleeding and platelet counts less than 20.000/mm ; for candidates for surgery , the american hematologic association recommends increasing platelet counts to above 50.000/mm .
our case of bilateral perirenal hematoma secondary to itp with a concurrent bilateral distal ureteral stone is the first such case report in the literature . in the management of distal ureteral stones , eswl and ureteroscopic lithotripsy
are effective and safe treatment modalities , but in patients with hemorrhagic diathesis , extreme care should be exercised for eswl . in a case report presented in japan , safe use of eswl
was mentioned in a ureteral stone patient with itp . in a study performed in patients with hemorrhagic diathesis , the frequency of severe perirenal bleeding secondary to eswl
did not report any cases of hematoma or bleeding in 17 patients with hemorrhagic diathesis following eswl .
however , in patients with hemorrhagic diathesis , coagulation tests should be done because of the risk of hematoma occurrence , and platelet counts should be increased above 50.000/mm . as far as we know
, our case had undergone a single session of eswl nearly 2 months previously for a left ureteral stone .
even though the risk of development of perirenal hematoma secondary to eswl increases in chronic itp , the absence of any urinary system symptoms in our patient after eswl and the application of eswl targeted to the distal ureter suggest that the bleeding was not a complication of eswl but rather originated from thrombocytopenia due to itp
. still , stasis and compression resulting from hydronephrosis caused by bilateral distal ureteral stones might be influential in the development of perirenal hematoma . in conclusion
, urinary system diseases can be seen in patients with bleeding diathesis , such as chronic itp , and related hematologic test results should be carefully evaluated in the following up and treatment of these patients . in these cases ,
therapeutic procedures targeting urinary system abnormalities can be optimally performed after normalizing hematologic test results while continuing itp therapy without making any change in the current treatment modalities .
Output:
| idiopathic thrombocytopenic purpura ( itp ) is an immune thrombocytopenia with a usually benign clinical course .
bleedings are mostly of the mucocutaneous type with mild symptoms
. massive bleedings requiring transfusion are rarely seen , unless the number of platelets decreases to extremely low levels . in this case ,
bilateral perirenal hematoma and bilateral distal ureteral stones were detected on a non - contrast computed tomography scan of a 57-year - old male patient who developed macroscopic hematuria during his treatment in the clinics of internal medicine because of left flank pain and diffuse petechial rashes all over his body .
the patient , who had been receiving chronic itp treatment for 1 year , had a very low platelet count ( 4,000/mm3 ) .
the patient was prescribed bed rest , and his platelet count increased to a safe level for surgical intervention of above 50,000/mm3 with administration of prednisolone , intravenous immune globulin , and platelet suspension .
a stone - free state was achieved after bilateral ureterorenoscopy and pneumatic lithotripsy .
a conservative approach was followed for the perirenal hematoma . upon regression of the perirenal hematoma ,
the patient was discharged at 9 weeks postoperatively . |
PubmedSumm6507 | ***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
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Input: it provides structural support in bone , cartilage , and the basement membrane ; specific association of cells with the ecm also provides contextual information that controls cellular phenotype , including differentiation , proliferation , or apoptosis .
ecm also regulates availability and activity of many signaling molecules , including tgf- , through controlled sequestration , presentation , and release .
the primary cell surface receptors for the ecm are the integrins , a family of 24 heterodimeric proteins composed of one of 18 -subunits and 8 -subunits .
integrins bind to motifs present in the ecm though an interaction domain located between the - and -subunit ; while many integrin - binding motifs have been identified , the best studied is the arginine - glycine - aspartate ( rgd ) sequence that is present in fibronectin and many other extracellular molecules .
integrins become activated in a process that is regulated both by availability of ecm substrate ( outside - in activation ) and signals from within the cell ( inside - out activation ) .
activated integrins can bind to the actin cytoskeleton and recruit a variety of cytosolic components into adhesion complexes . through those interactions integrins
can transduce biochemical signaling dependent on ecm composition , as well as directly link physical forces acting on the ecm to the cellular cytoskeleton ( fig .
stimulation of cellular signaling pathways can lead to increased affinity for binding sites in the ecm .
integrin ligation to the ecm triggers assembly of cytoplasmic molecules that can lead to focal adhesion complex formation and connection to the actin cytoskeleton
integrin activation .
stimulation of cellular signaling pathways can lead to increased affinity for binding sites in the ecm .
integrin ligation to the ecm triggers assembly of cytoplasmic molecules that can lead to focal adhesion complex formation and connection to the actin cytoskeleton
three tgf- isoforms are present in mammals , tgf-1 , -2 , and -3 , each encoded by a separate gene , and each playing distinct physiological roles during development .
exposure of cells to an active tgf- isoform leads to assembly of a tgf--ligated tetrameric receptor complex , composed of 2 type i and 2 type ii tgf- receptor subunits ( tgfbri and tgfbrii ) .
tgfbrii then phosphorylates tgfbri , enabling it to activate downstream signaling responses , which are regulated through canonical and noncanonical signaling pathways ( fig .
tgf- signaling can be initiated by binding of tgf- to tgf- receptor type iii ( tgfbriii ) , which can then assemble with tgf- receptors types ii and i ( tgfbrii , tgfbri ) to form an active signaling complex . in the canonical signaling pathway , the active signaling complex phosphorylates the receptor smads ( smad2 and smad3 ) , which then associate with smad4 , translocate to the nucleus and affect gene transcription . in the noncanonical pathway , phosphorylation of the tgf- receptor complex leads to activation of cytosolic signaling pathways , including mapk , pi3k / akt , and rho gtpases
tgf- signaling can be initiated by binding of tgf- to tgf- receptor type iii ( tgfbriii ) , which can then assemble with tgf- receptors types ii and i ( tgfbrii , tgfbri ) to form an active signaling complex . in the canonical signaling pathway , the active signaling complex phosphorylates the receptor smads ( smad2 and smad3 ) , which then associate with smad4 , translocate to the nucleus and affect gene transcription . in the noncanonical pathway , phosphorylation of the tgf- receptor complex leads to activation of cytosolic signaling pathways , including mapk , pi3k / akt , and rho gtpases . in the canonical signaling pathway , tgfbri phosphorylates the receptor smad proteins , smad2 or smad3 .
phosphorylated receptor smads associate with smad4 and the resultant oligomeric complex becomes translocated to the nucleus , where it can bind to a variety of other transcription factors and cofactors .
transcriptional alterations induced by the canonical pathway vary according to the strength and sustained maintenance of the tgf- receptor signaling , the composition and availability of existing transcriptional cofactors , and the epigenetic landscape of the chromatin at the time of tgf- pathway activation .
the gene expression effects are highly cell type and context dependent ; for example , the canonical signaling pathway inhibits expression of the inhibitor of differentiation ( id1 ) gene in normal mammary epithelial cells , but activates its expression in breast cancer cells . in the noncanonical signaling pathway , the activated tgf- receptor complex directly regulates non - smad - dependent pathways to activate , sustain , or modulate cellular responses .
non - canonical pathways include activation of erk / mapk signaling through tyrosine phosphorylation of tgfbr1 and recruitment of grb / shc , and subsequent activation of ras , which may contribute to tgf--dependent induction of senescence and prevention of transformation in normal human mammary epithelial cells .
tgf- can also induce jnk / p38 through a smad - independent pathway , which can then reinforce smad - dependent transcriptional alterations through a reactive oxygen species ( ros)-mediated mechanism .
rho family gtpases can be regulated through smad - independent tgf- signaling : rhoa , rac1 , and cdc42 can be activated in epithelial cells , or rhoa can be targeted for degradation via a pathway initiated by direct phosphorylation of the polarity protein par6 by tgfbrii .
tgf- can also activate akt through smad - independent induction of pi3k , which can in turn act as a regulator of the canonical pathway through phosphorylation of erk and consequent activation of smads .
the principal determinant and mediator of whether tgf- will signal through the canonical or noncanonical pathway in normal cells is smad7 , which is able to inhibit phosphorylation of receptor smads through multiple mechanisms .
smad7 is a transcriptional target of the canonical pathway , which constitutes a mechanism for channeling signaling from canonical to noncanonical pathways .
`` tgf- expression has been studied in many tumor types , where it has been found to function both as a tumor suppressor and a tumor promoter . in normal cells and in early stage tumors , tgf- acts to block cell proliferation through the canonical pathways , including via smad - dependent inhibition of myc , as well as activation of cyclin - dependent kinase inhibitors . additionally , in premalignant cells which have acquired oncogenic mutations , tgf- can induce apoptosis . in more advanced tumors ,
the tgf--dependent cytostatic effects are suppressed , and emt - associated cell invasion and metastasis become dominant . the transition from tumor - inhibitory to tumor - promoting behaviors has been described as the tgf- paradox , and while multiple components of this transition have been discovered , many aspects remain unknown . additionally , tgf- can induce a variety of different anti- and pro - tumorigenic effects indirectly by acting on stromal cells in the cancer microenvironment .
one of the most highly investigated roles of tgf- in pathology is in the context of development of tissue fibrosis . under normal circumstances
, tissue damage triggers a wound healing response characterized by deposition of transitional ecm , followed by activation and invasion of fibroblasts that remodel and contract the wound ecm ; once tissue homeostasis is restored , the fibroblasts undergo apoptosis . under fibrotic conditions ,
however , a feedback loop is activated in which excessive ecm deposition leads to increased proliferation and activation of ecm - producing fibroblasts . maintained for extended periods of time
, fibrosis can become a significant problem in its own right , and can also stimulate malignant transformation and promote tumor progression .
tgf- has been implicated as a critical player in chronic fibrosis of many organs , including lung , kidney , liver , and skin .
tgf- directly stimulates expression of ecm proteins , including collagen , fibronectin , and proteoglycans .
tgf- induces conversion of fibroblasts into myofibroblasts which can further contract and distort the ecm .
tgf- can also directly stimulate myofibroblast formation from epithelial and endothelial cells through emt - related processes , and this function is essential for development of fibrosis in several organs .
the relative amount of epithelial- vs fibroblast - derived myofibroblasts is a current point of debate and is likely to be highly tissue specific .
in addition to inducing integrin signaling through increased production of ecm , tgf- can also regulate integrin function directly .
tgf- can control expression of v- , 3- , and 1-integrin subunits through both canonical and noncanonical pathways , according to cell type .
tgf- signaling can also directly phosphorylate and activate 1-integrin , stimulating cell invasion and facilitating tissue regeneration .
tgf- can also induce cross - talk between integrins and growth factor receptors , including via activation of focal adhesion kinase ( fak)-dependent clustering of erbb2 ( her2 ) and integrins 6 , 1 , and 4 through a pathway initiated by egfr - dependent phosphorylation and activation of src ; the overall effect of this pathway is increased cell migration and survival .
tgf- isoforms are translated as preproproteins that contain a 2530 kda latency associated peptide ( lap ) and the 13 kda tgf- molecule .
lap - tgf- homodimers linked by disulfide bonds are formed in the endoplasmic reticulum ( er ) , followed by protoelytic cleavage of lap from tgf- in the golgi ; the resultant homodimers of tgf- and lap remain noncovalently associated following secretion as an inactive protein complex called the small latency complex ( slc ) .
many cell types also produce latent tgf--binding protein ( ltbp ) , which can covalently bind to the slc , producing the large latency complex ( llc ) , which can become associated with fibrillar ecm molecules . outside of the cell
, tgf- can be activated following release from the slc , which can occur through selective proteolytic digestion , exposure to ros , or through direct interaction with ecm molecules .
recent studies have identified a process by which tgf-1 and tgf-3 can be released from their lap - tgf- complex through a force - dependent conformational shift induced by association of rgd motifs in their respective lap proteins with integrins ; all v - containing integrins ( v1 , v3 , v5 , v6 , and v8 ) as well as 81 integrin have been shown to bind lap , although whether v1 and 81 can activate latent tgf- has not been determined .
the relevance of v integrin - mediated activation of latent tgf- was demonstrated by studies showing that transgenic mice with mutations in the rgd motif of the tgf-1-associated lap protein recapitulate the phenotype of the tgf-1 knockout mouse ; similar developmental alterations are seen in mice lacking a functional v - integrin gene . of v - containing integrins that can activate latent tgf- , v6- and v8-integrins have been shown to play a critical role in tgf- activation during development and in immune homeostasis , while v3 and v5 may play a more important role in tgf- activation during fibrosis .
( a ) integrin binding to latent tgf- complexes can lead to release of active tgf-. ( b ) signaling from integrins or tgf- receptors can stimulate expression of receptors or effectors of the other signaling pathway .
( c ) activation of integrins or tgf- receptors can lead to activation or inhibition of the other signaling receptor .
( d ) cooperative signaling from integrins and tgf- receptor may be necessary to stimulate phenotypic outcomes , including emt .
interaction of integrins and tgf- signaling pathways . ( a ) integrin binding to latent tgf- complexes can lead to release of active tgf-. ( b ) signaling from integrins or tgf- receptors can stimulate expression of receptors or effectors of the other signaling pathway .
( c ) activation of integrins or tgf- receptors can lead to activation or inhibition of the other signaling receptor .
( d ) cooperative signaling from integrins and tgf- receptor may be necessary to stimulate phenotypic outcomes , including emt .
in addition to controlling tgf- activation , integrins can also affect signaling downstream of the tgf- receptor .
this can occur through integrin - mediated activation of the tgf- receptor , through stimulation of canonical and noncanonical signaling pathways , and through increased transcription of genes encoding tgf- and tgf- receptor isoforms .
recent studies have shown that the pathways regulating these effects vary in different cell and tissue types .
activity of 1-integrins and the integrin signaling mediator integrin - linked kinase ( ilk ) are required for tgf--induced emt in mammary epithelial cells .
integrin 31 is necessary for tgf--induced emt of alveolar epithelial cells and development of pulmonary fibrosis , and integrin 11 is required for tgf--induced kidney fibrosis .
furthermore , the response of the tgf receptor can be potentiated through binding of specific integrins to tgfbrii , leading to phosphorylation of the receptor in a fak- and src- dependent manner .
these effects can be quite cell - type specific : in mammary epithelial cells , the activation of tgfbrii by interaction with integrin 3 is inhibited by signaling from integrin 1 , while in chondrocytes , integrin 1 preferentially associates with and activates tgfbrii . as an additional layer of control
, the strength of the signal from the tgf- receptor complex depends on which tgf- ligand is bound , as the ligands vary in their ability to bind to tgfbri and to assemble the active tetrameric receptor complex with tgfbrii ; the co - receptor , tgfbriii , can further modulate the ligand - dependent assembly and activation of the complex .
while a role for integrin - mediated regulation of tgf- and receptor isoform expression is relatively unexplored , it is known that activation of integrin 51 stimulates tgfbrii expression , while expression of both tgfbri and tgfbrii can be repressed by integrin v3 .
as tgf- has been found to play a central role in promotion of tumor cell invasion and metastasis , stimulation of pathological emt , and induction of cancer - promoting microenvironmental changes , it is unsurprising that there has been considerable effort to develop inhibitors targeting the tgf- pathway as potential cancer therapeutics . to date , multiple inhibitors of the tgf- signaling have been developed and tested in animal models and clinical trials .
these include monoclonal antibody - based inhibitors of tgf- signaling , for example fresolimumab ( gc1008 ) , a fully human monoclonal antibody against tgf--1 , -2 and -3 , currently tested in clinical trials for combinatorial treatment with radiation therapy in metastatic breast cancer ( clinicaltrials.gov identifier : nct01401062 ) and in glioma ( clinicaltrials.gov identifier : nct01472731 ) .
another avenue for tgf- pathway inhibition is through synthetic antisense oligonucleotides , such as trabedersen ( ap 12009 ) , targeting tgf-2 , currently being tested for treatment of glioma , pancreatic cancer , melanoma and colorectal cancer .
other types of tgf- pathway inhibitors include small molecule tgf- receptor kinase inhibitors which bind to and directly block receptor signaling , as well as peptide aptamers which bind to and inhibit downstream mediators of the tgf- pathway , such as smads . an alternative way to interfere with tgf- signaling would be to target v integrin subunit integrins required for activation of latent tgf-. multiple anti - integrin v small molecule synthetic inhibitors and monoclonal anitbodies have been developed and are being tested in preclinical and clinical trials . among these , the monoclonal antibody intentumumab is currently being tested in patients with melanoma ( clinicaltrials.gov identifier : nct00246012 ) and prostate cancer ( clinicaltrials.gov identifier : nct00537381 ) .
it should be noted that , given the pleiotropic effects of tgf- and potential development of resistance , the current paradigms for targeting tgf- signaling in cancer treatment have focused on short term dosing in combination with other therapies .
it can act as a tumor suppressor , blocking proliferation and inhibiting stromal mitogens , as well as a tumor promoter and an inducer of cancer - associated emt , allowing evasion of immune surveillance and stimulating invasion and metastatic spread .
those opposing consequences of tgf- signaling are highly cell type dependent and regulated by the cellular context .
ecm is a key regulator of both initiation of tgf- signaling and a determinant of its outcomes .
integrins , acting as bidirectional signal transducers between the cellular microenvironment and the cell itself , play crucial roles in this process . often , the presence of certain integrins is required for activation of latent tgf- and thus induction of downstream signaling pathways ; integrins can also lead to ligand - independent signaling via activation of tgf- receptor .
the complexity and dual nature of tgf- signaling effects reinforce the need to specifically study the context and determinants of those different responses .
moreover , while it is the paradigmatic view that in early stages of tumor development tgf- acts to inhibit proliferation , whereas in later stages that aspect of signaling is lost in favor of promotion of emt and invasiveness , we should be mindful that this phenotypic transition from cytostasis to motility is unlikely to occur in every cell within a tumor , and that competition between pathways responsible for these different phenotypes likely leads to complex and sometimes unexpected outcomes .
most importantly , if tgf- pathway is to be targeted in cancer therapy , the challenge remains to predict the types and stages of tumors in which tgf- signaling inhibition would prevent metastasis without facilitating growth of the primary tumor .
this work was supported by grants from nih ( ca116201 ) , susan b. komen foundation ( kg110542 ) , and jimmy v. foundation .
Output:
| extracellular matrix ( ecm ) provides both structural support and contextual information to cells within tissues and organs .
the combination of biochemical and biomechanical signals from the ecm modulates responses to extracellular signals toward differentiation , proliferation , or apoptosis ; alterations in the ecm are necessary for development and remodeling processes , but aberrations in the composition and organization of ecm are associated with disease pathology and can predispose to development of cancer .
the primary cell surface sensors of the ecm are the integrins , which provide the physical connection between the ecm and the cytoskeleton and also convey biochemical information about the composition of the ecm .
transforming growth factor- ( tgf- ) is an extracellular signaling molecule that is a powerful controller of a variety of cellular functions , and that has been found to induce very different outcomes according to cell type and cellular context .
it is becoming clear that ecm - mediated signaling through integrins is reciprocally influenced by tgf- : integrin expression , activation , and responses are affected by cellular exposure to tgf- , and tgf- activation and cellular responses are in turn controlled by signaling from the ecm through integrins .
epithelial - mesenchymal transition ( emt ) , a physiological process that is activated by tgf- in normal development and in cancer , is also affected by the composition and structure of the ecm . here
, we will outline how signaling from the ecm controls the contextual response to tgf- , and how this response is selectively modulated during disease , with an emphasis on recent findings , current challenges , and future opportunities . |
PubmedSumm6508 | ***TASK***
the task is to summarize an input biomedical literature in six sentences
***INPUT***
the input is a biomedical literature
***OUTPUT***
the output is the summary of an input biomedical literature in six sentences
***DOCUMENTATION***
***EXAMPLES***
Input: we recently applied a urea in - solution digestion ( uisd ) method to prepare protein from ffpe tissue for liquid chromatography tandem mass spectrometry ( lc - esi - ms / ms ) , providing a more efficient workflow relative to qproteome ffpe tissue kit .
uisd poses several advantages to other preparation techniques : preparation is carried out in a single tube minimizing sample handling , urea is lc - esi - ms / ms compatible requiring no additional washing beyond desalting , and both of these factors enhance sample throughput .
however , artificial carbamylation is introduced when using urea at elevated temperatures , reducing trypsin digestion efficiency . in solution , urea is in equilibrium with isocyanate and ammonium . between ph 7 and 9 , isocyanate reacts with -amines on n - termini and -amines on lysine side chains of peptides to form carbamyl groups .
trypsin digestion efficiency was reduced by carbamylation , and uisd had more missed cleavages and a lower lysine to arginine ( k : r ) peptide terminal amino acid ratio relative to the commercially available qproteome ffpe tissue kit ( qkit ) .
ammonium bicarbonate , included in the uisd extraction buffer , inhibits carbamylation when using urea as a protein denaturant , but its efficacy is greatly reduced above 37c [ 4 , 5 ] . despite having this drawback , uisd preparation detected similar numbers of peptides and proteins obtained using qkit and some not detected by qkit with a bias toward arginine terminal peptides .
it has been demonstrated previously that ffpe tissue shows high equivalence with fresh tissue , but ffpe preservation introduces peptide modifications , particularly lysine methylation . as ffpe tissue appears to be an unreliable substrate for investigating lysine modifications , the introduction of lysine carbamylation primarily affects proteomic study by reducing cleavage efficiency . in addition
, the introduction of artificial carbamylation with isotopically labeled urea can provide an alternative quantitative tool to conventional methods .
the benefits of uisd as a preparation method outweigh the drawback of reduced cleavage efficiency , and in this study we optimize its application to ffpe tissue .
there are multiple approaches which may enhance protein solubility and enhance digestion efficiency for uisd . in this study
, we test each condition separately and some in combination to find the optimum identifiable peptide solubility while maintaining the minimum level of introduced carbamylation .
different factors including buffer composition , ph , temperature of extraction , and duration of extraction were investigated .
the tumor was fixed using 10% neutral buffered formalin and processed by an automated processor into a paraffin - embedded block .
serial 4 m slices were made on a microtome and mounted on glass slides .
the first and last slices were stained with hematoxylin and eosin to ensure the tissue was homogenous tumor cells across serial sections and to select tissue for analysis .
slide mounted ffpe tissue sections were deparaffinized twice in xylene for 5 min followed by two washes in 100% ( v / v ) ethanol for 5 min .
the tissue was then hydrated in 85% ( v / v ) ethanol for 1 min , 70% ( v / v ) ethanol for 1 min , and distilled water for 1 min .
protein was macrodissected with a 30-gauge needle from pairs of serial sections that were randomized between each set of extraction conditions with a total area of 1650 mm .
tissue was placed directly into a 2 ml microtube containing 160 l of freshly prepared 7 m urea , 2 m thiourea , and 1 m ammonium bicarbonate with modifications outlined in table 1 .
protein digestion was carried out using reconstituted proteomics grade trypsin with concentrations outlined in table 1 ( sigma - aldrich , st .
after digestion , 99.8% acetic acid ( acros organics , fair lawn , nj , usa ) was added dropwise to reduce to ph 4 , and the solution was desalted using c18 peptide cleanup tubes according to the manufacturer 's instructions ( agilent technologies inc .
total protein was quantified by the reducing agent compatible bicinchoninic acid protein assay according to the manufacturer 's instruction ( pierce , rockford , il , usa ) .
three technical replicate injections from each extraction condition were analyzed using lc - esi - ms / ms system in a nanospray configuration ( absciex 6600 tripletof , ab sciex , framingham , ma , usa ) coupled with eksigent nanolc 415 with a chiplc system ( eksigent , dublin , ca , usa ) as previously described . the paragon and pro group algorithms were used for protein identification and grouping in proteinpilot 5.0 ( ab sciex , framingham , ma , usa ) .
data analysis parameters included data - dependent analysis , h. sapiens as the species , iodoacetamide cysteine alkylation , and trypsin digestion , and the analysis was carried out both with and without urea denaturation considered as a special factor .
all data files were searched using a uniprotkb / swissprot database downloaded in august of 2015 .
positive protein detection for comparisons between methods was defined as two peptide matches per protein and a global false discovery rate of 1% .
a series of conditions were tested to inhibit peptide carbamylation and to maximize protein yield ( table 1 ) .
peptide carbamylation was an important factor for the performance of uisd that can affect spectral data analysis .
a summary of results from proteinpilot without urea denaturation considered as a special factor for data analysis is shown in table 2 and the summary of results from proteinpilot with urea denaturation considered as a special factor is shown in table 3 .
the improvements with this search setting are demonstrated by the gain in spectra and peptides detected at < 1% fdr .
improvements in the identification of peptide spectra indicate better detection of peptides with urea denaturation induced artifacts .
all uisd conditions increased the number of spectra , peptides , and proteins detected with urea denaturation considered as a special factor ( tables 2 and 3 ) . additionally , the number of carbamyl groups detected and the number of missed cleavages detected both increased for all uisd conditions under the same search parameters ( tables 2 and 3 ) .
the most significant improvement for uisd is that protein and peptide detection were better than qkit for multiple conditions tested when accounting for urea induced modifications , and the values in table 3 are used in further comparisons between methods .
the paragon algorithm is used in proteinpilot to identify peptides from mass spectra measured during lc - esi - ms / ms .
give a complete description on how the paragon algorithm uses a scoring method to modulate search space based on evidence from sequence tags .
briefly , probabilities are calculated for peptide hypotheses based on predefined parameters set by the user such as digestion enzyme , alkylating agent , and special factors ; these probabilities are empirically determined by measuring how frequently they occur .
this is an important feature of the algorithm for this study because the special factor of urea denaturation selected in the search settings provided better peptide detection for uisd preparation of ffpe tissue . selecting urea denaturation accounts for the empirically determined frequency that urea induced
modifications like carbamylation occur which are built into the algorithm to influence the probability of a given peptide hypothesis . in conjunction with peptide hypothesis probabilities , segment probabilities based on de novo sequence tags termed sequence temperature value for regions of the sequence database and protein probabilities based on initial precursor mass filtered search
are used to generate an overall probability that determines the search space segments of the sequence database .
extraction temperature affects the total protein yield from ffpe tissue , but greater overall protein yield did not always result in the most detected proteins . the control condition with longest high temperature extraction yielded only 2.9 g / mm but detected the most proteins of all uisd conditions ( table 3 ) .
ikeda et al . and fowler et al . found short term intense heating at 100c for 20 minutes followed by extended mild heating at 60c or 80c for 2 hours provided the optimum protein recovery from ffpe tissue [ 9 , 10 ] .
similar conditions were applied to uisd starting with extraction at 60c for 2 hours in condition ( a ) as shown in table 1 , and it yielded 1.1 g / mm more than control . even though condition ( a ) had greater overall protein yield , 347 fewer proteins were detected relative to control ( table 3 ) . extracting protein for 5 minutes at 95c prior to 2 hours at 60c provided no change to results relative to condition ( a ) ( data not shown ) . increasing extraction time at 95c to 20 minutes prior to extraction at 60c for 2 hours in condition ( b ) increased the total protein yield by 3.3 g / mm relative to control .
longer extraction time at mild temperature used in condition ( b ) resulted in detection of only 16 fewer proteins than control while increasing the number of detected peptides by 1030 ( table 3 ) . in condition ( c ) , extraction at 95c was maintained at 20 minutes , but it was followed by 80c instead of 60c for 2 hours ( table 1 ) .
condition ( c ) yielded 2.3 g / mm more protein than control but also resulted in detection of 44 fewer proteins .
since the extraction temperature in condition ( b ) made the most improvement in peptide detection , the remaining conditions were tested using these extraction temperatures combined with changes to buffer composition ( table 1 ) . in an attempt to reduce isocyanate formation , 3 m ammonium bicarbonate ( sigma - aldrich , st .
louis , mo , usa ) alone was introduced to the extraction buffer , but carbamylation remained unchanged and fewer proteins were detected than control ( data not shown ) . in condition ( d ) , ammonium bicarbonate was increased to 2 m and ph was reduced to 7.2 with hcl ( sigma - aldrich , st .
louis , mo , usa ) to test the effect of ph on extraction while maintaining a higher concentration of ammonium .
total protein yield for condition ( d ) was 1.6 g / mm lower than condition ( b ) , and it detected 384 fewer proteins and 2324 fewer peptides .
one major drawback for using neutral ph to enhance digestion efficiency is that extraction buffers with ph > 8 have been shown previously to be important for protein yield .
other buffer changes were made to maximize solubility and protein yield beyond gains seen with temperature manipulation . in order to approach protein yield of qkit , 6% -mercaptoethanol ( sigma - aldrich , st .
louis , mo , usa ) was added for extraction under reducing conditions , but yield and protein detection were reduced relative to control ( data not shown ) .
shen et al . found that 0.2% zwittergent 3 - 16 yielded better results than buffer containing 8 m urea , and the result was attributed to the enhanced lytic strength of the detergent .
in order to enhance cell lysis and protein solubility , 0.2% zwittergent 3 - 16 ( santa cruz biotechnology , dallas , tx , usa ) was included in the extraction buffer for condition ( e ) , and this was combined with the extraction temperatures from condition ( b ) ( table 1 ) .
the addition of 0.2% zwittergent 3 - 16 decreased total protein yield 1.19 g / mm relative to condition ( b ) , and 930 fewer peptides and 55 fewer proteins were detected ( table 3 ) . due to the limited amount of available clinical tissue that was used for this study , only a single tissue section was available to test the effect of zwittergent 3 - 16 on total protein yield . as the total yield for condition ( e ) , 6.01 g / mm , was only slightly lower than the 6.16 g / mm yield for condition ( b ) and protein and peptide detection levels were within previously seen ranges , a second replicate was not included for this modification .
in addition , the number of proteins and peptides detected was not sufficiently different from condition ( b ) to justify a second tissue section .
after maximizing the peptide detection and total protein yield of uisd , the second goal for manipulating extraction temperature was to limit lysine carbamylation for enhanced digestion efficiency .
the percentage of carbamylated peptides reached a minimum of 2.2% for uisd with only 60c extraction in condition ( a ) , and it also resulted in k : r of 0.643 , the highest obtained using uisd .
condition ( b ) had 7.9% less total carbamylation than control while detecting 1030 more peptides .
the percentage of missed cleavages out of the total number of peptides was 7.3% lower and total carbamylation was 7.9% lower for condition ( b ) relative to control .
condition ( c ) reduced carbamylation by only 3.1% relative to control . as an alternative to decrease lysine carbamylation , reduction of ph to near 7 should increase bias toward n - terminal carbamylation rather than lysine carbamylation since -amines react faster at more neutral ph than -amines .
condition ( d ) reduced ph to 7.2 with 2 m ammonium bicarbonate and successfully decreased total carbamylation to 17.7% compared to 52.4% for condition ( b ) using the same extraction temperature .
the fraction of carbamyl lysine residues out of total peptides was reduced by 23.8% relative to condition ( b ) , and carbamyl n - termini only decreased by 0.2% .
missed cleavages for condition ( d ) were also decreased by 29.3% relative to condition ( b ) .
the reduction in carbamylation for condition ( d ) approached condition ( a ) by lowering ph instead of temperature , but peptide and protein detection was decreased for both relative to condition ( b ) or control ( table 3 ) . both condition (
a ) and condition ( d ) had reduced carbamylation and showed smaller gains in terms of the number of proteins , peptides , and spectra gained when accounting for urea denaturation in the search conditions or not , further demonstrating the importance of accounting for urea induced modifications ( tables 2 and 3 ) .
elimination of high temperature extraction and neutral buffer ph both reduced carbamylation only at the cost of reduced overall protein and peptide detection .
the sample is also heated at 37c for overnight digestion , which is a long period to introduce additional peptide carbamylation at a slower rate . as an alternative to extraction manipulation , trypsin digestion was limited to 30 minutes at 50c for condition ( f ) using extraction time and temperature from condition ( b ) in order to reduce overall sample exposure time to heating while maintaining adequate yields ( table 1 ) .
carbamylation for condition ( f ) was increased by 1.0% relative to condition ( b ) .
missed cleavages were elevated for condition ( f ) relative to all other uisd conditions , and arginine missed cleavages in particular were elevated for condition ( f ) , indicating reduced overall digestion efficiency for rapid digestion independent of lysine carbamylation ( table 3 ) .
any enhancement cleavage efficiency at lysine residues was negated by reduced overall digestion efficiency under rapid digestion . accelerated digestion reduces sequence coverage and has been cautioned against for complex protein mixtures . as previously mentioned for condition ( e ) ,
a single tissue section replicate was used for condition ( f ) due to the clearly apparent reduction in digestion efficiency from the increased number of missed arginine cleavages from a single tissue section . in this study ,
overall digestion efficiency was reduced , but accelerated preparation may outweigh the reduced efficiency given the need for rapid sample preparation .
uisd provides a protein extraction workflow from ffpe tissue with minimal sample handling steps , but it introduces significant artificial modifications to peptides in the form of carbamylation .
carbamylation reduces trypsin digestion at lysine residues leading to the generation of predominantly arginine terminal peptides . despite this bias , distribution of sequence coverage across the set of conditions
is very similar to those obtained using qkit with positive skew across all conditions ( figure 1(a ) ) .
the higher temperatures used in control and condition ( c ) both show a smaller interquartile range in addition to reduced median sequence coverage relative to all other conditions ( table 3 ) .
demonstrated that incomplete trypsin digestion provides more complete proteome coverage in a simple protein mixture by minimizing small peptide generation and decreased ion intensity .
the distribution of detected peptide lengths across the different conditions varied little ( figure 1(b ) ) .
uisd condition ( b ) had a slightly higher average peptide length of 15 6 amino acids compared to qkit with 13 5 .
no advantage in sequence coverage was seen relative to qkit in terms of overall distribution of protein sequence coverage , but conditions with the optimum temperature ( b ) , ( d ) , ( e ) , and ( f ) all show greater numbers of proteins with very high sequence coverage as outliers in the distribution ( figure 1(a ) ) .
the lack of any improvement may be due to limitations of the mass detection range by lc - esi - ms / ms for longer peptides or limited sampling due to the relatively short 60-minute elution gradient used for lc - esi - ms / ms ( figure 1(a ) ) .
improvements to sequence coverage and overall detection of peptides can be made by peptide fractionation prior to lc - esi - ms / ms . as we pointed out in our previous paper analyzing this method ,
overall protein detection and total protein yield vary across studies using different instrumentation , tissue type , and data analysis methods , making direct comparisons difficult across studies .
when artifacts introduced by uisd using control conditions are accounted for during analysis , the optimized uisd condition ( b ) detects more proteins and peptides than qkit with comparable distribution of sequence coverage and equivalent yield .
protein extraction at 95c for 20 minutes followed by 60c for 2 hours provided the best total protein yield and best peptide detection for the tissue analyzed . modifications to extraction buffer or digestion conditions all reduced overall performance for uisd . despite artificially introducing carbamylation , the optimized uisd conditions detected more peptides and proteins relative to qkit with a comparable distribution of protein sequence coverage making it a useful method for proteomic studies . during data analysis of mass spectra , considering urea denaturation as a special factor is important for maximizing protein and peptide detection with the paragon algorithm .
this study has two main limitations : first using only a limited amount of clinically available tissue for extraction method comparisons and second the inability to modify or view specific calculations in the proprietary software used to analyze mass spectra .
uisd provides efficient protein extraction that can be applied to clinically relevant ffpe tissue for proteomic analysis providing a useful tool for target development in immunohistochemical studies .
Output:
| urea based protein extraction of formalin - fixed paraffin - embedded ( ffpe ) tissue provides the most efficient workflow for proteomics due to its compatibility with liquid chromatography electrospray ionization tandem mass spectrometry ( lc - esi - ms / ms ) .
this study optimizes the use of urea for proteomic analysis of clinical ffpe tissue .
a series of protein extraction conditions manipulating temperature and buffer composition were compared to reduce carbamylation introduced by urea and increase protein detection .
each extraction was performed on a randomized pair of serial sections of homogenous ffpe tissue and analyzed with lc - esi - ms / ms .
results were compared in terms of yield , missed cleavages , and peptide carbamylation .
lowering extraction temperature to 60c decreased carbamylation at the cost of decreased protein detection and yield .
protein extraction for at least 20 minutes at 95c followed by 60c for 2 hours maximized total protein yield while maintaining protein detection and reducing carbamylation by 7.9% .
when accounting for carbamylation during analysis , this modified extraction temperature provides equivalent peptide and protein detection relative to the commercially available qproteome ffpe tissue kit .
no changes to buffer composition containing 7 m urea , 2 m thiourea , and 1 m ammonium bicarbonate resulted in improvements to control conditions .
optimized urea in - solution digestion provides an efficient workflow with maximized yields for proteomic analysis of clinically relevant ffpe tissue . |
PubmedSumm6509 | ***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: according to the world health organization ( who ) , obesity can be defined as the accumulation of body fat in an abnormal and/or excessive manner showing serious health problems . in this scenario ,
overweight and obesity are considered a serious public health problem , and it is therefore a subject of considerable impact and worldwide interest .
this particular condition characterized by increased adipose tissue from the positive energy calculation in the relation intake versus calorie expenditure has a multifactorial etiology ; among these we can highlight genetic susceptibility , metabolic disorders , sex , age , occupation , diet , and others [ 2 , 3 ] .
the concern with this health condition is becoming increasingly clear since the exponential increase in its prevalence and incidence , due to declining levels of physical activity and increased inadequate food intake [ 46 ] .
it is estimated that the worldwide prevalence of obesity in the period between 1980 and 2008 has doubled ; today it is estimated that worldwide approximately 2.8 million annual deaths are related to the harmful effects of excess weight [ 1 , 79 ] , raising global public spending as a result of this condition [ 10 , 11 ] . until recently , obesity was considered a problem only in developed countries ; however , it is currently on the rise in developing countries [ 1 , 79 ] . in brazil ,
the overweight and obesity are on the rise among children and adolescents , mainly after the age of five , in all economic classes and in all regions . between 2008 and 2009
the excess weight reached 33.5% of children from five to nine years old and within this group 16.6% of boys were obese , while 11.8% of girls were obese .
overweight in childhood predisposes the short- and long - term comorbidities such as diabetes mellitus , hypertension , and dyslipidemia .
since children are still in their infancy , early control is necessary at this stage of life , in order to avoid an unfavorable long - term prognosis , as in adulthood .
future complications of this condition in adulthood can be serious if early intervention measures are not established . in this context
, it is essential to identify the prevalence of obesity and overweight children and adolescents in brazil and in which regions of the country .
for this reason , the aim of this systematic review is to determine the prevalence of overweight and obesity in children and adolescents from the age range of 2 to 19 years old in different regions of brazil .
a systematic review was conducted according to the recommendations of the preferred reporting items for systematic reviews and meta - analyses ( prisma ) .
this review included prospective and/or cross - sectional designs studies on the prevalence of overweight and obese infant juvenile in different regions of brazil .
inclusion criteria were as follows : brazilian studies , with subjects aged 219 years , considered obese and/or overweight .
there was no language restriction for the search , and all included studies were translated where necessary and possible .
the search for relevant scientific articles was conducted by independent researchers in electronic databases such as medline ( pubmed ) , lilacs , and scielo from september through november 2013 .
the search was structured as pico , acromion for target patient , intervention , control , and outcome .
the search was based on the words of the dictionary medical subject heading terms ( mesh ) , descriptors , and boolean operators .
the first search was conducted in pubmed database as follows : ( ( obesity ) , and ( overweight ) and ( child ) and ( prevalence ) and ( brazil ) ) .
the searches in the subsequent databases were adjusted according to the specifications needed for the databases keeping similar words in the search process . in order to complement the search process ,
a manual search was performed of the references included in the articles found in the databases .
initially , the studies were selected according to the title , then the abstracts were reviewed , and only those which were potentially eligible were selected . based on the abstracts , full articles were acquired for the final analysis . in case of disagreement between reviewers , a third reviewer made the decision on the eligibility of the study .
a total of 191 articles were identified in the search ( figure 1 ) ; 72 were selected for evaluation in accordance with the title and their revised abstracts .
based on these eligible articles for a full review , a total of 17 articles met all the proposed inclusion criteria . from the 17 articles identified in this systematic review , all used cross - sectional designs . when verified the scope of the studies , 16 [ 1834 ]
were carried out at the municipal level , just , and one particular study was carried out statewide . after searching the databases
when the geographic regions are observed , studies for seven articles were performed in the south of brazil ( states of rio grande do sul , santa catarina , and paran ) , five in the southeast ( states of so paulo , rio de janeiro , espirito santo , and minas gerais ) , three in the northeast region ( states of maranho , piau , rio grande do norte , cear , paraba , pernambuco , alagoas , bahia , and sergipe ) , one in the north region ( states of acre , amazonas , rondnia , roraima , amap , par , and tocantins ) , and one in the central west of brazil ( states of mato grosso , mato grosso do sul , gois , and distrito federal ) ( figure 2 ) ( table 2 ) . taking into account the year of publication
, there was an increase in the number of articles published in the last five years .
likewise , it is important to point out that there was an exponential increase in the number of individuals evaluated ( 5,889 in the period from 2003 to 2008 and 10,227 in the period from 2009 to 2012 ) . in different regions of brazil
, there was a variation in the prevalence rates of overweight and obesity . in the south ,
the rates were approximately 25.7% and 10.4% , respectively , with subjects aged 618 years . in the southeast ,
rate of overweight was 13.7% and obesity 15.4% , with subjects aged 219 years . in the northeast region ,
rate of overweight was 15.8% and obesity 4.3% with population aged 619 years . in the north ,
the only study found showed a prevalence of 28.8% overweight with population aged 619 years .
likewise , the only study in the central west region showed a prevalence of overweight of 16.8% and 5.3% obesity in children aged 610 years .
the results of this study demonstrated that a higher prevalence of overweight was found in the south ( 25.7% ) and northeast ( 28.8% ) of the country , as well as a higher prevalence of obesity in the southeast ( 15.4% ) and south ( 10.4% ) .
note that only one study was conducted in the north region , showing the limitation of this particular finding .
however , regardless of the region in which different studies had been conducted , a high prevalence of overweight and obesity in brazilian children and adolescents was identified .
currently , the increasing prevalence of obesity and overweight in children and adolescents is observed worldwide and it has effects on the status of health and quality of life . in brazil , data from the national demographic and health survey indicated that 7.3% of children under 5 years old are overweight .
another national study found that one in three children aged 5 and 9 years are overweight , according to the guidelines of the world health organization . a survey conducted in the period from 2008 to 2009 by the brazilian institute of geography and statistics in partnership with ministry of health showed that the prevalence of overweight among children aged 59 years increased from approximately 13.4% in 1989 to 33.4% in 2008 .
regarding adolescents , the same survey in 1989 showed a prevalence of overweight of 10.8% and obesity of 1.3% , in which the rates were increased to 20.5% and 4.9% , respectively .
in a study realized in the united states , in the period from 1999 to 2012 , it was revealed that 17.3% of children were obese , and 5.9% and 2.1% were in obesity classes 2 and 3 , respectively .
another survey showed that , in the age group 219 years old , 16.9% of north americans were obese . in latin america
, a systematic review showed that between 18.9% and 36.9% of children of school age ( 59 years old ) and between 16.6% and 35.8% of adolescents ( 1219 years old ) are obese .
in this particular study it is estimated that 20% to 25% of children and adolescents between 5 and 19 years old are affected by obesity .
these findings demonstrate the clinical and epidemiological relevance of obesity in the context of public health in brazil and in the world as it has become a global epidemic , directly affecting the world population .
the development of juvenile obesity is related to eating habits , level of physical activity , sedentary practices , socioeconomic status , and genetics , among others [ 4042 ] ; however , it is attributed to the increase of overweight in children and adolescents , observed in recent decades , the concomitant decline in levels of physical activity , and increased eating inappropriate behaviors [ 4345 ] significant effects on body composition of these individuals .
studies included in this review demonstrated an association between overweight and inactivity in children and young brazilians , ranging from 39% to 84.4% [ 18 , 29 ] . these findings can be explained by the fact that a sedentary lifestyle is currently facilitated by technological advances ( e.g. , computers , television , and video games ) , which make no need for children to struggle physically , unlike some years ago . for fear of urban violence and by the request of the parents , staying indoors with activities that do not encourage them to do physical activities such as running , playing ball , and playing hide and seek results in spending most of the time in sedentary [ 18 , 29 ] .
the fast foods are adopting marketing strategies , aiming to capture the preference of the infantile public , and became immensely popular in brazil .
it is believed that the time spent watching television and using the computer and video games is an indicator of sedentary behavior that is associated with obesity .
also , the time spent on these activities is aggravated by excessive calorie intake and by minimum nutritious food intake , often induced by the media , because the children are mainly exposed to unhealthy food advertising on television .
our findings corroborate such information once they have demonstrated a strong association between poor eating habits of children and young brazilians and overweight .
it is important to highlight that the presence of a sedentary life in obese brazilian children and adolescents is an important risk factor , since physical inactivity has been directly related as a decisive factor in the current global epidemic of overweight and obesity in all age groups [ 45 , 49 ] . in developing countries ,
economic factors strongly influence the determination of the prevalence of overweight and obesity in a superior way compared to biological determinants [ 50 , 51 ] .
young brazilians have a higher prevalence of overweight when residing in urban areas , higher family income , and higher socioeconomic status , which is in line with our findings .
it is well known that the pathological process of obesity may result in consequences such as the short - term ones in cardiovascular and metabolic system as hypertension , hypercholesterolemia , cardiovascular dysfunction , insulin resistance , diabetes mellitus type 1 , and atherosclerosis . in the same manner ,
the long - term consequences include the persistence of obesity into adulthood with associated comorbidities , including cardiovascular disease , diabetes type 2 , and premature death [ 13 , 53 ] . from the 17 articles selected , seven of them [ 19 , 21 , 22 , 25 , 26 , 30 , 33 ] also presented the information on the prevalence of hypertension and dyslipidemia associated with overweight and obesity in brazilian children and adolescents at the municipal level . in relation to hypertension
, studies have been conducted in the south region ( n = 2 ) , southeast ( n = 2 ) , and northeast ( n = 1 ) with prevalence that may reach values of up to 13.6% in the northeast , 13.5% in the south , and 11.7% in the southeast .
only two studies investigated the values of dyslipidemias , one in the southeast and another one in the north , and both showed increased levels of triglycerides , total cholesterol , and low density lipoprotein ( ldl ) and reduced levels of high density lipoprotein ( hdl ) .
although a small number of studies [ 19 , 21 , 25 , 26 , 30 , 33 ] have addressed the cardiovascular and metabolic comorbidities in this population , the results showed significant prevalence of hypertension and hypercholesterolemia in young brazilians . for being children and adolescents , borderline and/or high values for systolic blood pressure ( sbp ) and diastolic blood pressure ( dbp )
changes in lifestyle , involving a combination of diet and physical activity are essential elements in the management of juvenile obesity and recommended by national and international entities .
moreover , emergency strategies for brazilian children and adolescents , as well as the development of overweight and obesity prevention programs , avoiding the associated diseases , are essential , reducing the economic impacts of this condition [ 54 , 55 ] since in addition to being seen as a major public health problem , obesity is responsible for the high financial cost in the global economy [ 10 , 11 ] . based on that , there is a growing worldwide concern because over the years the country will face the economic impact of the increasingly high incidence of this condition , mainly due to the comorbidities associated with the disease [ 5658 ] . in this context , the supply of information on the major health problems of the population to the decision makers can support the development of the field of public health policy directed to this condition .
furthermore , such information should be aligned with the growing concern for the best achievable outcome in terms of public health policies .
the limitations of the findings in this study may have been attributed to the existence in the systematic review of only cross - sectional designs studies , which are characterized by not involving periodical monitoring of individuals , and could be useful in better establishment of associations between factors risk . in addition , cross - sectional designs studies do not allow measuring any changes in eating behavior and lifestyle [ 1834 ] . in developing countries , studies on the juvenile obesity are still limited .
our systematic review showed a reduced number of prevalence studies in different brazilian regions with the absence of nationwide studies , limiting a more conclusive statement on the prevalence of this public health problem that affects brazil .
finally , regardless of the country and its regional divisions , it is a must for all parents , educators , and health professionals to ensure the health of children and adolescents with overweight by attitudes that are consistent with established guidelines in order to promote health and reduce morbidity and mortality , trying thus to reverse the alarming prevalence rates expected to rise up .
in this systematic review , only 17 articles contemplated all inclusion criteria established in this study and demonstrated a higher prevalence of overweight and obesity in the south , southeast , and northeast regions of brazil . the investigated studies were mostly municipal scope , which limited conclusive analysis on this subject .
the gap in the literature became evident , showing the need for further studies of prevalence at the national level , with emphasis on public health in obese children and adolescents throughout the brazilian territory .
thus , it will be possible to obtain more direct and specific actions for the regions of brazil in need of assistance as a result of this global epidemic that is spreading alarmingly in the brazilian territory .
Output:
| introduction .
infant juvenile obesity is currently a worldwide public health problem and it is increasing at alarming rate in the brazilian population , showing its relevance in terms of public health . objectives .
determine the prevalence of overweight and obesity in children and adolescents between 2 and 19 years old in different regions of brazil .
methods .
the following electronic databases were searched ( from september through november 2013 ) : medline ( pubmed ) , lilacs , and scielo , using the descriptors and boolean operators ( obesity ) and ( overweight ) and ( child ) and ( prevalence ) and ( brazil ) .
prospective and/or cross - sectional designs studies were found regarding the prevalence of overweight and obese children and adolescents in the five regions of brazil .
results .
a total of 191 scientific articles were found of which 17 met all inclusion criteria .
a higher prevalence of overweight was found in the south ( 25.7% ) and north ( 28.8% ) of the country , and obesity in the southeast ( 15.4% ) and south ( 10.4% ) .
conclusions .
the scope of the studies was mostly based on municipal coverage , which resulted in limitations for conclusive analysis , showing the need for further studies of prevalence at the national level , with emphasis on public health in obese children and adolescents throughout the brazilian territory . |
PubmedSumm6510 | ***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: for patients with newly diagnosed breast carcinoma , evaluation of the extent of the disease in the breast is of paramount importance in planning appropriate surgical therapy . magnetic resonance imaging ( mri )
plays an ever increasing role in the evaluation of additional areas in the affected breast deemed suspicious but indeterminate by other radiologic modalities .
technical developments such as mri with high spatial resolution , special breast coils , dynamic kinetic imaging techniques , and intravenous contrast agents contribute to enhanced diagnosis of breast abnormalities . while excitement about
the role of this modality in improving the planning of surgical treatment of breast cancer patients is increasing [ 16 ] , many areas of uncertainty remain , especially related to the clinical importance of additional lesions that are detected by the use of mri [ 79 ] . in this study
we evaluated the pathologic findings in mri - guided needle core biopsies of the breast obtained from other suspicious areas in the affected breast of patients with a new diagnosis of breast carcinoma .
our study population consisted of 44 mri - guided needle core breast biopsies performed on 40 patients with newly diagnosed breast carcinoma at rush university medical center , chicago , il , usa between may 2007 and july 2008 .
overall , 9/44 ( 20.4% ) of our mri - guided breast biopsies were malignant , 29/44 ( 66% ) were benign , and 6/44 ( 13.6% ) showed atypia ( table 1 ) . of the 9 malignant cases , 4 were infiltrating ductal carcinomas with tubular features , 2 infiltrating lobular carcinomas , and 3 ductal carcinoma in situ lesions ( table 2 ) .
of the 6 atypical cases , 2 were atypical ductal hyperplasia ( adh ) , 2 were atypical lobular hyperplasia ( alh ) , and 2 showed areas of columnar cell hyperplasia with atypia ( table 3 ) . of interest ,
more than one third of our benign cases ( 11/29 , 38% ) consisted of a specific complex multicystic lesion lined by apocrine metaplastic epithelium , a lesion we called
during the last few years there has been a heightened interest in the application of magnetic resonance imaging ( mri ) in the management of breast cancer .
currently , mri is used as a supplemental tool to complement conventional methods of radiologic and ultrasonographic breast evaluation .
a number of appropriate indications for the clinical use of mri in breast cancer diagnosis and management include clarification of questionable findings on mammography , evaluation and accurate staging of breast tumors in dense breasts , accurate evaluation of specific subtypes of breast carcinomas such as infiltrating lobular carcinoma , assessment of response to preoperative chemotherapy , diagnosis of occult primary breast tumors presenting with axillary nodal involvement , and surveillance programs assessing high - risk patients such as breast cancer gene carriers or patients with a history of chest irradiation [ 16 ] .
however , as the use of mri at the time of new diagnosis of early stage breast cancer is quickly becoming a new standard of care , there is heightened concern that routine use of mri for preoperative staging may lead to more extensive surgery , while solid evidence for improvement of surgical management , improved rates of local control , or improved overall prognosis is lacking [ 812 ] .
in addition , while in a number of studies the detection of additional foci of breast cancer by mri in the affected breast is reported to be around 16% ( ranging from 6 to 34% ) [ 12 , 13 ] , only limited information exists on the histology of the additional lesions that mri testing falsely identifies as worrisome . in this paper
, we report that mri - guided needle core biopsies of separate lesions in the affected breast of patients with newly diagnosed breast carcinoma show additional foci of malignancy in 20% of cases . a high percentage ( 66% ) of these additional suspicious areas by mri are benign by histologic examination .
more specifically , mri - guided needle core biopsies seem to target a characteristic complex multicystic lesion lined by apocrine metaplastic epithelium , in over one third of the cases , a lesion we called
our findings suggest that mri - guided core biopsies result in an important change of detection of additional foci of malignancy in a significant number of cases .
in addition , mri - directed needle core biopsies often target benign lesions with specific histopathologic characteristics , namely , a characteristic complex multicystic lesion lined by apocrine epithelium , the so - called cystic apocrine metaplasia . we suggest that awareness of the correlation of this benign lesion with abnormal mri findings by radiologists will be helpful as they evaluate breast mri studies of patients with newly diagnosed early stage breast carcinoma . ongoing carefully controlled studies comparing the strengths and weaknesses of breast mri to those of conventional breast imaging in different clinical scenarios , as well as detailed correlation of mri findings to underlying histopathology of breast lesions , are urgently needed in order to clearly define diagnostic criteria for widespread mri use .
Output:
| the role of mri in the management of breast carcinoma is rapidly evolving from its initial use for specific indications only to a more widespread use on all women with newly diagnosed early stage breast cancer .
however , there are many concerns that such widespread use is premature since detailed correlation of mri findings with the underlying histopathology of the breast lesions is still evolving and clear evidence for improvements in management and overall prognosis of breast cancer patients evaluated by breast mri after their initial cancer diagnosis is lacking . in this paper
, we would like to bring attention to a benign lesion that is frequently present on mri - guided breast biopsies performed on suspicious mri findings in the affected breast of patients with a new diagnosis of breast carcinoma . |
PubmedSumm6511 | ***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: electrophysiological studies in animal models have shown that propafenone reduces the maximum rate of rise and the amplitude of the action potential ( 1 ) , and increases the duration of the action potential ( 2 , 3 ) .
furthermore , the drug has been shown to depress the transient outward current ( ito ) in atrial myocytes of the rabbit and ventricular myocytes of the rat ( 4 ) , the hyperpolarization - activated inward current ( if ) in isolated human atrial myocytes ( 5 ) and the delayed rectifier current ( ikr ) in sinoatrial node cells and atrial myocytes of rabbits and ventricular myocytes of guinea pigs ( 3 , 4 , 6 ) .
voltage - operated potassium currents play important roles in shaping and terminating cardic action potentials .
although several potassium current components have been isolated , two types of currents can be distinguished : fast activating and inactivating currents , referred to as ito , and delayed , more slowly inactivating currents , referred to as ikr ( 7 ) . for ito , in particular , kv1.4 potasium channel has been identified or discussed , since the kv1.4 channel carries the ito current which is a major contributor to the repolarizing currents terminating the cardic action potential .
several experiments have showed that the expression of kv1.4 channels in heart is altered under pathologic conditions associated with arrhythmias .
thus , 1 ) hyperthyroidism drastically decreased the protein level of kv1.4 in cultured newborn rat ventricular myocytes ( 8) ; 2 ) rats with infarcted myocardium showed reduced mrna and protein levels of kv1.4 in different regions of left ventricular myocardium ( 9 ) ; 3 ) cardic hypertrophy in rats ( induced by phorbol esters ) increased the density of kv1.4 ( 10 ) ; 4 ) diabetic heart ( induced by streptozotocin ) yielded a increase of kv1.4 mrna density and protein level in rat ventricle ( 11 ) .
therefore , understanding the molecular basis of the kinetic behavior of kv1.4 channels in response to changes in ph and [ k]0 may be of considerable physiological important .
we used an n - terminal deletion construct of kv1.4 ( kv1.4n ) , which lacks rapid n - type inactivatin , but exhibits robust c - type inactivation ( 12 , 13 ) . in the present study
, we aimed to investigate effects and mechanism of action of propafenone on the kv1.4n channel , and to examine the response to changes in ph and [ k]0 .
the constructs and sequences of the cdnas ferret kv1.4n ( fkv1.4n ) used in this study have been previously described ( 12 , 13 ) .
ferret kv1.4n channels possess slow ( c - type ) inactivation ( 12 , 13 ) .
removal of residues 2 - 146 from the n - terminal domain ( fkv1.4n ) results in the loss of the fast component of inactivation but leaves c - type inactivation .
oocytes were collected from mature female xenopus laevis under anaesthesia ( immersion in 1.5 g l tricaine ) . the follicular layer was removed enzymatically by placing the lobes in a collagenase - containing , ca - free or2 solution ( mm : 82.5 nacl , 2 kcl , 1 mgcl2 and 5 hepes , ph 7.4 , with 1 - 2 mg ml collagenase ( type i , sigma ) .
the oocytes were gently shaken for about 2 hr and collagenase activity was then halted by bovine albumin as previously described ( 12 ) .
defolliculated oocytes ( stage v - vi ) were then injected with transcribed crnas ( up to 27 - 34 nl ) and incubated at 18 for 24 - 72 hr in antibiotic - containing barth 's solution ( mm : 88 nacl , 1 kcl , 2.4 nahco3 , 0.82 mgso4 , 1.5 cacl2 and 5 hepes , ph 7.4 ) which was supplementd with penicillin ( 100 iu / ml ) .
oocytes were clamped using a two - microelectrode bath clamp amplifier ( ca-1b , dagan corp , minneapolis , mn , u.s.a . ) .
microelectrodes were made from borosilicate glass tubing and had a resistance of 0.5 - 1 m for the current electrodes and 1 - 2 m for the potential electrodes when filled with 3 m / l kcl . during recording , oocytes were continuously perfused with control solution ( mm : 96 nacl , 2 kcl , 1 mgcl2 , 1.8 cacl2 and 10 hepes , adjusted to ph 7.4 with naoh ) or high extracellular potassium concentration solution ( mm : 98 kcl , 1 mgcl2 , 1.8 cacl2 and 10 hepes , adjusted to ph 7.4 with naoh ) or normal extracellular potassium concentration solution ( mm : 93 nacl , 5 kcl , 1 mgcl2 , 1.8 cacl2 and 10 hepes , adjusted to ph 7.4 with naoh ) or low extracellular potassium concentration solution ( mm : 97 nacl , 1 kcl , 1 mgcl2 , 1.8 cacl2 and 10 hepes , adjusted to ph 7.4 with naoh ) the ph value of this solution was changed in some experiments and was set 6.0 with hcl and to 8.0 with naoh .
whenever propafenone was used , 10 min of perfusion time was used to allow equilibration of propafenone with the oocyte .
propafenone ( as hydrochloride ; sigama , isenhofen , bayern , germany ) in final concentrations of 0.01
m / l up to 1,000 m / l was added to the bath solution .
all experimnts were performed at days 1 and 3 after injection of crna and were carried out at room temperature ( 221 ) .
data were recorded on videotape using an a / d vcr adaptor ( axon instruments , union city , ca , u.s.a . ) and were digitised and analysed directly using pclamp 9 software ( axon instruments , union city , ca , u.s.a . ) , microsoft excel ( microsoft , redmond , wa , u.s.a . ) . unless otherwise stated , raw data traces from two - microelectrode voltage - clamp recordings were not leakage or capacitance subtracted .
the potassium current amplitude was measured at the peak of current obtained during the depolarizing voltage step .
conductance - voltage relations were obtained by normalizing the conductance data to the maximal value under control conditions and by fitting the data to the boltzmann equation y = gmax ( 1+exp [ ( v1/2-v)/b ] ) , where y is the normalized conductance , gmax is the normalized maximal conductance , v1/2 is the potential of the half - maximal conductance , v is the voltage , and b is the slope factor .
concentration - response curves were determined by fitting the mean current values at different prop concentrations to the langmuir equation y=(kd / c)/[1+(kd / c ) ] , where y is the fraction of control current , kd is the half blocking concentration , c is the concentration of prop , and is the hill coefficient .
the voltage dependence of block was determined using the kd values that were obtained for these calculations from the fractional current ( f ) , measured as the current in the presence of propafenone ( prop ) at a concentration [ d ] of 100 m and under control conditions ( ictrl ) at the end of the voltage step : f = iprop / ictrl and kd=[d]f/(1-f ) .
the constructs and sequences of the cdnas ferret kv1.4n ( fkv1.4n ) used in this study have been previously described ( 12 , 13 ) .
ferret kv1.4n channels possess slow ( c - type ) inactivation ( 12 , 13 ) .
removal of residues 2 - 146 from the n - terminal domain ( fkv1.4n ) results in the loss of the fast component of inactivation but leaves c - type inactivation .
oocytes were collected from mature female xenopus laevis under anaesthesia ( immersion in 1.5 g l tricaine ) . the follicular layer was removed enzymatically by placing the lobes in a collagenase - containing , ca - free or2 solution ( mm : 82.5 nacl , 2 kcl , 1 mgcl2 and 5 hepes , ph 7.4 , with 1 - 2 mg ml collagenase ( type i , sigma ) .
the oocytes were gently shaken for about 2 hr and collagenase activity was then halted by bovine albumin as previously described ( 12 ) .
defolliculated oocytes ( stage v - vi ) were then injected with transcribed crnas ( up to 27 - 34 nl ) and incubated at 18 for 24 - 72 hr in antibiotic - containing barth 's solution ( mm : 88 nacl , 1 kcl , 2.4 nahco3 , 0.82 mgso4 , 1.5 cacl2 and 5 hepes , ph 7.4 ) which was supplementd with penicillin ( 100 iu / ml ) .
oocytes were clamped using a two - microelectrode bath clamp amplifier ( ca-1b , dagan corp , minneapolis , mn , u.s.a . ) .
microelectrodes were made from borosilicate glass tubing and had a resistance of 0.5 - 1 m for the current electrodes and 1 - 2 m for the potential electrodes when filled with 3 m / l kcl . during recording
, oocytes were continuously perfused with control solution ( mm : 96 nacl , 2 kcl , 1 mgcl2 , 1.8 cacl2 and 10 hepes , adjusted to ph 7.4 with naoh ) or high extracellular potassium concentration solution ( mm : 98 kcl , 1 mgcl2 , 1.8 cacl2 and 10 hepes , adjusted to ph 7.4 with naoh ) or normal extracellular potassium concentration solution ( mm : 93 nacl , 5 kcl , 1 mgcl2 , 1.8 cacl2 and 10 hepes , adjusted to ph 7.4 with naoh ) or low extracellular potassium concentration solution ( mm : 97 nacl , 1 kcl , 1 mgcl2 , 1.8 cacl2 and 10 hepes , adjusted to ph 7.4 with naoh ) the ph value of this solution was changed in some experiments and was set 6.0 with hcl and to 8.0 with naoh .
whenever propafenone was used , 10 min of perfusion time was used to allow equilibration of propafenone with the oocyte .
propafenone ( as hydrochloride ; sigama , isenhofen , bayern , germany ) in final concentrations of 0.01 m / l up to 1,000 m / l was added to the bath solution .
all experimnts were performed at days 1 and 3 after injection of crna and were carried out at room temperature ( 221 ) .
data were recorded on videotape using an a / d vcr adaptor ( axon instruments , union city , ca , u.s.a . ) and were digitised and analysed directly using pclamp 9 software ( axon instruments , union city , ca , u.s.a . ) , microsoft excel ( microsoft , redmond , wa , u.s.a . ) . unless otherwise stated , raw data traces from two - microelectrode voltage - clamp recordings were not leakage or capacitance subtracted .
the potassium current amplitude was measured at the peak of current obtained during the depolarizing voltage step .
conductance - voltage relations were obtained by normalizing the conductance data to the maximal value under control conditions and by fitting the data to the boltzmann equation y = gmax ( 1+exp [ ( v1/2-v)/b ] ) , where y is the normalized conductance , gmax is the normalized maximal conductance , v1/2 is the potential of the half - maximal conductance , v is the voltage , and b is the slope factor .
concentration - response curves were determined by fitting the mean current values at different prop concentrations to the langmuir equation y=(kd / c)/[1+(kd / c ) ] , where y is the fraction of control current , kd is the half blocking concentration , c is the concentration of prop , and is the hill coefficient .
the voltage dependence of block was determined using the kd values that were obtained for these calculations from the fractional current ( f ) , measured as the current in the presence of propafenone ( prop ) at a concentration [ d ] of 100 m and under control conditions ( ictrl ) at the end of the voltage step : f = iprop / ictrl and kd=[d]f/(1-f ) .
with application of depolarizing voltage steps to oocytes injected with fkv1.4n crna , outward currents appeared at potentials of around -40 mv ( fig .
the administration of 100 m / l propafenone resulted in a decreased of the sustained currents ( fig . 1b , open squares ) .
the block of the sustained currents showed a voltage dependence with the largest blocking effect at the highest amplitudes ( fig .
100 m / l propafenone reduced the amplitude of the current to 41% of the control value .
the block appeared to be voltage - dependent and to be increased in the positive potential range ( from 614% fraction of control current amplitude at -40 mv to 322% at + 50 mv with 100 m / l propafenone ) .
voltage dependence of propafenone - induced block of fkv1.4n currents was presented after application of 10 m / l , 100 m / l , and 1,000 m / l propafenone , respectively . at a potential + 50 mv , 1,000 m / l propafenone ( fig .
2 , triangles ) reduced the amplitude of the current more than that of 100 m / l ( fig .
frequent - dependent block of fkv1.4n channels induced by propafenone can be identified in fig .
the current induced by the first pulse of the pulse train in the presence of 100 m propafenone was dramatically decreased comparing with that in the pre - drug control ( p<0.05 , n=5 ) and then quickly reaches a steady - state current level , when the cell was continuously stimulated at 1 hz .
all these behaviors reflected the process of 100 m propafenone blocking fkv1.4n ( at + 50 mv ) and showed a use - dependent kinectics .
it showed with the increasing of numbers of opening channels , the block of propafenone on fkv1.4n increased , that is open channel block .
4 showed the effect of propafenone on fkv1.4n recovery from inactivation with a standard two - pulse protocol .
the fkv1.4n channel in propafenone recovered more slowly than the channel in control ( fig .
4a ) ( p<0.05 , n=5 ) . with the increasing of inter - pulse duration ,
it can be concluded that closed state inactivation does not exist and just open channel block exists .
the 50% recovery time was 98089.39 ms for controland it was 1,653.15108.45 ms for drug - treated group ( fig .
4b ) ( p<0.05 , n=5 ) . this change in time constant with propafenone suggests that prpafenone can accelerate the inactivation of fkv1.4n currents ( fig . 5 , n=8 ) .
at a potential of + 50 mv the time constants of monoexponential fits were found to 4,494508 ms under control conditions and 704179 ms with 100 m / l propafenone .
there was significant difference between the time of constants for fkv1.4n under control conditions and propafenone with 100 m / l .
the concentration dependence of the propafenone effect was obtained by eliciting fkv1.4n currents at propafenone concentrations between 1 m / l and 1,000 m / l and by fitting the amplitudes of the currents with langmuir equations ( fig .
the maximal block of the fkv1.4n currents was 93% and was almost completely blockade by 1,000 m / l .
the concentration dependence of the propafenone effect was also studied in high - potassium solution ( 98 mm ) , normal - potassium solution ( 5 mm ) and low - potassium solution ( 1 mm ) in fig .
the fractioins of inhibition of propafenone at a concentration of 1,000 m / l were 83% , 89% , and 94% , respectively .
the ic50 for propafenone block of the fkv1.4n currents in 98[k]0 , 5 mm[k]0 , and 1 mm[k]0 were 153 m / l , 128 m / l , and 94 m / l , respectively .
effects of extracellular ph on the concentration dependence of the propafenone effect were studied on fkv1.4n currents in extracellular potassium concentration of 98 mm[k]0 , 5 mm[k]0 , and 1 mm[k]0 ( fig .
7 , n=5 ) . with extracellular potassium acide solution ( ph 6 , triangles ) ,
neutral solution ( ph 7.4 , squares ) and alkaline solution ( ph 8 , diamonds ) , propafenone was applied in concentration between 10 m / l and 1,000 m / l and the currents were fitted with langmuir equations . as described in literature ,
the kinetics of the fkv1.4n currents were ph - dependent and the deactivation was accelerated with acidification and slowed down with alkalization in high- , normal- and low- extracellur potassium concentration .
whereas the ic50 value increased in acidic solution to 463 m / l , it was decreased in the alkaline extracellular solution to 58 m / l ( differences statistically significant ) for the high extracellular potassium concentration .
therefore , understanding the molecular basis of the kinetic behavior of kv1.4 channel in response to changes in ph and [ k]0 may be of considerable physiological importance .
ion channels undergo substantial physical rearrangements during gating when they transition between conducting and non - conducting states .
this rearrangements can have a strong influence on channel affinity and drug binding , access to binding sites , and the environment in which they are in , can be altered considerably .
the result of study allow to infer on the mechanisms of action of propafenone at the fkv1.4n channel molecule .
the voltage dependence of the block suggests that the amount of block increased with the relative conductance and thus with the open probability of the fkv1.4n channel .
this means that the block because more effective when the period of time was prolonged in which fkv1.4n channel was in the open state .
the finding allow the conclusion that propafenone blocks the fkv1.4n channel in the open state .
this is consistent with blocking mechanisms of propafenone found for kv1.5 ( 15 ) and herg channel ( 16 ) .
the use dependence of the block shows with the increasing of numbers of opening channels , the block of propafenone on fkv1.4n increased , that is open channel block .
previous studies have shown that propafenone binds to the open conformation of herg channels , and that propafenone inhibit the transient outward k current in human atrium , but this study is the first to examine the relationship between propafenone binding and c - type inactivation in a voltage - gated k channel .
concerning the site of action of propafenone on fkv1.4n channel , the results are not decisive .
however , there is one line of evidence might be interpreted to point to a block by propafenone from the intracellular with lowering of the ph value . in acidic solution
, propafenone has to cross the cell membrane and since it is more likely that unchanged molecules can transverse into the cell interior , a changing of propafenone by protonation can be assumed to reduce the concentration of propafenone within the cell , thus causing smaller blocking effects . for this interpretation , however , it has to be taken into consideration that the change of efficacy of propafenone can be assumed to be affected by the time the channel remained in the open state by reducing the probability of open channel block .
almost the same result has been found for the effect of the antiarrhythmic drug quinidine at the kv1.5 channel and has been taken as an argument for an action from the inside .
there are two main hypotheses concerning the link between occlusion of the intracellular pore by drug or lipophilic peptides and the coupling to c - type inactivation : the " permeation " mechanism and the " allosteric " mechanism .
the permeation mechanism ( 17 ) is based on the idea that blocking permeation directly effects c - type inactivation .
the reduction in [ k]0 means fewer k ions bind to the extracellular binding site , so there is no hindrance to the channel adopting the c - type inactivated state ( 17 ) .
the allosteric mechanism ( 18 , 19 ) proposes that the effect of reducing the k accumulation is negligible compared to the contribution from a direct physical interaction between events at the intracellular pore and c - type inactivation , which are mediated by the channel protein .
c - type inactivation involves a conformational change at the extracellular mouth of pore ( 20 ) .
however , considerable evidence is emerging to indicate that c - type inactivation also involves major conformational changes on the intracellular side of the channel .
the channel was regarded as an integrated unit in conformational terms , i.e. a conformational change at a remote site may result in allosteric changes throughout the protein .
this leads to the results that an action at the intracellular face of the channel can affect an extracellular event such as c - type inactivation .
transmembrane communication with allosteric mechanisms connecting physically remote sites has already been demonstrated for kv1.4 channels , eg .
mutating a valine at the c - terminal end of s6 has a dramatic effect on c - type inactivation of the kv1.4 channel ( 21 ) .
elevation of [ k]0 can reduce the affinity for drug binding by a direct ( electrostatic or knock - off ) effect or by an indirect effect via modification of the pore region by some kind of conformational change ( allosteric effect ) , or by a combination of both ( 22 ) .
if the direct electrostatic effect was the basis of the interaction , elevating [ k]0 should reduce propafenone binding to kv1.4n channel .
however , our data show that increasing [ k]0 had no significant effect in ic50 of propafenone for fkv1.4n .
this suggests that the modulation of drug binding by [ k ] is not the result of an electrostatic interaction .
the allosteric mechanisms dominate coupling in fkv1.4n channels , and , by extension , may dominate in the wild type channel .
recent studies have shown that propafenone blocks the kv2.1 channel in the open state from the intracellular side by entering the inner vestibule of the channel .
these results are consistent with a direct interaction of propafenone with the lower part of the pore helix and/or residues of s6 .
these data show there is a link between c - type inactivation mediated pore closure and the propafenone - binding sites in the intracellular vestibule region .
since the orientation of s6 is critical to drug binding ( 23 ) , and recent studies have shown a link between this domain and c - type inactivation ( 21 ) , this suggests that s6 moves during c - type inactivation .
therefore , the conformational change accompanying c - type inactivation includes more of the channel than previously thought and has allosteric effect on the intracellular propafenone - binding site .
previous studies have shown that ph change influence of c - inactivation involves the change on h508 and k532 , and that a model of kv1.4 pore based on the crystal structure of kcsa , shows that h508 and k532 lie close together .
our study concludes that propafenone acts from the intracellular side of the membrane , and may result in a structural change near the sites of h508 and k532 .
several regions have been found that when replaced by the corresponding parts of the kv1.2 channel , reduced the sensitivity of the prop for kv2.1 channel ( 24 ) .
because there is growing evidence that these parts of the channel form an intracellular compartment placed near membrane - associated part of the channel pore ( 25 ) , the intracellular termini and the s4-s5 linker might impair the access of prop to its proper site of action in the internal mouth of the channel . a complete abolition of prop sensitivity of kv2.1 ( to the level of kv1.2 ) was found with exchanges of the linker s5-s6 , as well as with the s6 segment itself .
based on radiography analysis of the kcsa potassium channel , these parts can be assumed to form the inner wall of the pore proper ( 26 ) .
the intracellular amino and carboxyl terminus and the intracellular linker s4-s5 reduced the blocking effect of propafenone , whereas the linker s5-s6 , as well as the segment s6 of the kv1.2 channel . in the linker s5-s6 , this effect could be narrowed down to two groups of amino acids ( groups 372 to 374 and 383 to 384 ) , which also affected the sensitivity tetraethylammonium . in segment s6 ,
several amino acids in the intracellularly directed part of the helix significantly reduced propafenone sensitivity ( 24 ) .
taking all the findings into consideration , we suggest that prop enters the cell by allosteric mechanism across the cell membrane and acts from the intracellular side .
pror blocks the kv1.4n channel in the inner vestibule of the channel while it is in the open state .
residues of segment s6 might contribute to this impairment or to the formation of the binding site , which most probably includes the lower part of the pore helix .
Output:
| the effects of the antiarrhythmic drug propafenone at c - type kv1.4 channels in xenopus laevis oocytes were studied with the two - electrode voltage - clamp techinique .
defolliculated oocytes ( stage v - vi ) were injected with transcribed crnas of ferret kv1.4n channels . during recording
, oocytes were continuously perfused with control solution or propafenone .
propafenone decreased the currents during voltage steps .
the block was voltage- , use- , and concentration- dependent manners .
the block was increased with positive going potentials .
the voltage dependence of block could be fitted with the sum of monoexponential and a linear function .
propafenone accelerated the inactivate of current during the voltage step .
the concentration of half - maximal block ( ic50 ) was 121 m / l . with high , normal , and low extracellular potassium concentrations , the changes of ic50 value had no significant statistical differences .
the block of propafenone was ph- dependent in high- , normal- and low- extracellular potassium concentrations .
acidification of the extracellular solution to ph 6.0 increased the ic50 values to 463 m / l , alkalization to ph 8.0 reduced it to 58 m / l .
the results suggest that propafenone blocks the kv1.4n channel in the open state and give some hints for an intracellular site of action . |
PubmedSumm6512 | ***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: leiomyoma is a benign smooth muscle neoplasm of mesenchymal origin which commonly occurs in the genitourinary system and the gastrointestinal tract of the body but which rarely occurs in the liver [ 1 , 2 ] .
the first case report of primary leiomyoma of the liver was first described in a 42-year - old woman by demel in 1926 .
this paper seeks to review primary leiomyoma of the liver in the literature because of its rarity , unclear pathogenesis , and the diagnostic challenges it poses in clinical practice .
case reports and case series of primary leiomyoma of the liver were retrieved by extensive literature search of pubmed , ovid sp , cochrane database of systematic reviews , embase , and clinical evidence online .
further search of the literature was carried out by manually searching the relevant references of the studies retrieved .
the inclusive criteria include relevant publications of primary leiomyoma of the liver and hence studies with coexisting leiomyoma in other parts of the body were excluded .
epidemiologic , pathologic , clinical , imaging , and prognostic data were retrieved and assessed for all studies .
the search keywords include primary hepatic leiomyoma , primary leiomyoma of the liver , primary benign lesions of the liver , and primary tumours of the liver .
the clinical and pathologic characteristics of the 35 cases reviewed with the treatment and the clinical outcome are outlined in table 1 .
eighty - seven years after the first case of primary leiomyoma of the liver was reported , to the best knowledge of the author , 36 cases of primary leiomyoma of the liver have so far been reported in the literature .
hawkins et al . in 1980 proposed criteria that must be met for the diagnosis of primary liver leiomyoma .
secondly , the presence of leiomyoma in other sites of the body like uterus and the gastrointestinal tract must be excluded .
if the uterus is surgically absent , the diagnosis of primary leiomyoma of the liver must not be made without the review of the report and sections from the hysterectomy .
there are reports in the literature to suggest the incidence of the tumour in both immunocompetent and immunosuppressed patients .
primary leiomyomas of the liver have been reported to have female sex predilection [ 2 , 57 ] .
luo et al . suggested that the observed female preponderance may be partly due to the activity of the smooth muscle cells in female urogenital tissue in carcinogenesis .
however this view seems to contradict one of the main diagnostic criteria for primary leiomyoma of the liver as proposed by hawkins et al . which seeks to exclude leiomyoma in other parts of the body especially in the urogenital tissue .
this review of 36 cases however demonstrates slight female sex affectation with females accounting for 55.6% of the cases .
the distribution of the lesion is equal in both right and left lobes of the liver with two cases involving the caudate lobe of the liver [ 8 , 9 ] .
proliferations of smooth muscle of the hepatic vessels or the biliary tree have been suggested as a possible origin [ 2 , 1013 ] . however
the argument against origin from the bile ducts is that large extra hepatic ducts have very few smooth cells [ 11 , 14 ] .
immunosuppressive states which include either posttransplant patients on immunosuppressive therapy or patients with human immunodeficiency virus ( hiv ) have been suggested as a possible causal factor in primary leiomyoma of the liver .
increased risks of de novo neoplasia after transplantation are well documented in the literature [ 1517 ] .
possible explanations for the susceptibility of immunocompromised patients to neoplasms include the disruption of the immunosurveillance ability of the host with the subsequent development of the tumours that would otherwise have been suppressed by a normal immune system .
the incidence of primary leiomyoma of the liver within the setting of immunosuppression in this review which accounts for 39.3% of the cases appears to be in support of this theory [ 2 , 10 , 1825 ] .
immunosuppression alone does not totally explain the pathogenesis of this tumour because of the incidence of the tumour in immunocompetent individuals .
this is because of the evidence that implicates some dna viruses in the aetiology of some neoplasms particularly epstein - barr virus in smooth muscle tumours [ 16 , 18 ] .
this theory is further supported by the observation that patients with immunosuppression are at high risks of developing virus - associated neoplasms although the exact mechanism is not known [ 18 , 26 ] .
a possible explanation is a multistep theory of viral oncogenesis which suggests that virus infected cells undergo an uncontrolled polyclonal proliferation in the setting of the reduced immune surveillance of the viral transformed cells .
further cytogenetic events alter the growth regulation of a subset of cells , leading to a monoclonal expansion of tumour cells . in support of this theory
is the observation that 5 cases were reported to be positive for ebv in this review and the 5 cases were also in the setting of immunosuppression [ 10 , 1820 , 22 ] .
the fact that other case reports in this review were not associated with epstein - barr virus suggests a rather complex pathogenesis for primary leiomyoma of the liver .
virus associated tumours have been observed to exhibit different range of differentiation from well differentiated to poorly differentiated and some may show features suggestive of leiomyosarcomas .
the risk of other cancers in patients with immunosuppression not linked to viruses is also increased [ 2830 ] .
the clinical presentation of primary leiomyoma of the liver is similar to the presentation of other liver neoplasms .
the most common clinical symptom in this review is abdominal , epigastric , or right upper quadrant pain which accounts for 42.4% of cases reported [ 13 , 5 , 11 , 13 , 1921 , 3133 ] .
33.3% of the cases were incidental with one of them an incidental finding at autopsy .
other clinical features include abdominal mass [ 4 , 7 , 12 , 34 , 35 ] , abdominal discomfort , dyspepsia , and liver dysfunction .
reported the case of a 59-year - old lady with 13 10 9 cm firm tumour with mainly a solid tissue portion and interconnected multilocular cystic lesions .
screening for tumour markers alpha fetoprotein , carbohydrate antigen 19 - 9 and carcinoembryonic antigen are usually negative [ 11 , 12 , 19 ] .
serological testing for ebv combined with in situ hybridization indicates the tumour cells positive for ebv encoded small rna ( figure 1 ) [ 2 , 10 , 18 , 20 ] . in situ hybridization
imaging alone does not show tissue specific diagnosis and can not reliably differentiate between primary leiomyoma and other differential diagnosis like leiomyosarcoma , hepatocellular adenoma , hepatocellular carcinoma , angiomyolipoma , and hypervascular metastatic lesions [ 36 , 37 ] .
ct findings in leiomyoma of the liver have been variously reported in the cases reviewed as hypodense lesions with strong enhancement in both arterial and portal phase [ 5 , 11 , 13 , 21 , 23 , 36 , 38 ] with some reports describing peripheral rim enhancement [ 8 , 37 ] .
an increased enhancement in the arterial phase and a sustained homogeneous enhancement in both hepatic venous and equilibrium phases have also been reported ( figure 2 ) .
ultrasound findings in primary leiomyoma of the liver in the literature have been described as hypoechoic lesions with varying degrees of heterogeneity [ 5 , 8 , 11 , 36 , 37 ] .
reported heterogeneous mass displacing the inferior vena cava ( ivc ) and the right kidney medially across the midline .
mri findings from several studies suggest hypointense lesions on t1-weighted mri images with hyperintense lesions on t2-weighted sequences with inhomogeneous contrast uptake [ 8 , 19 , 20 , 37 ] .
however hypointense lesions in the t2-weighted mri images have also been reported which the authors associated with the dense fusocellular nature of the tumour . the development of liver specific mr contrast agents which includes reticuloendothelial system specific contrast agents and hepatocytes specific contrast agents have been shown to potentially improve the detection and characterization of liver lesions by providing functional and morphologic information of the liver simultaneously [ 3941 ] .
gadobenate dimeglumine is a gadolinium - based contrast agent that is partially taken up by functioning liver cells and excreted without biotransformation through the biliary duct system .
gadobenate dimeglumine shows a vascular - interstitial distribution in the first minutes after bolus injection .
normal liver and benign liver lesions show increased signal intensity on t1-weighted mr images during the delayed liver - specific phase because of active contrast uptake by functioning hepatocytes .
the absence of contrast retention during the liver - specific phase is believed to be indicative of malignant liver lesions .
it has also been suggested that liver specific mr contrast agents may be misleading in the diagnosis of primary leiomyoma of the liver .
the absence of contrast retention during the liver specific contrast enhanced mri , in the case report , led them to suspect a malignant lesion of the liver but it turned out to be a primary leiomyoma on histology after surgical resection .
this finding is consistent with earlier reports in the literature that demonstrated equivocal appearance of primary leiomyoma of the liver after the administration of liver specific contrast agents [ 36 , 41 ] .
hawkins also reported a selective angiogram through the left hepatic artery which demonstrated abnormal mass effect , stretching of the feeding vessels , and scattered pooling throughout the tumour .
attempts have been made to make a preoperative diagnosis of this tumour so as to prevent unwarranted diagnostic surgical procedures .
ct guided fine needle biopsy had reportedly failed to determine the nature of the mass despite the fact that the primary leiomyoma of the liver in this case was the largest ever reported in the literature with a size of 30 cm .
percutaneous biopsy was attempted with mixed outcomes in the two cases reported by sadler et al . .
well differentiated smooth muscle neoplasm consistent with hepatic leiomyoma while multiple attempts at percutaneous biopsy were not successful in the second case .
sousa et al . initially performed a us - guided fine needle aspiration ( fna ) which was inconclusive because of because of insufficient sample which included only a small group of normal looking hepatocytes .
the histological review of the 18 g trucut biopsy sample taken by sousa et al . proved to be accurate in the diagnosis of leiomyoma of the liver which was further confirmed after surgical resection .
this accurate preoperative diagnosis from biopsy sample is consistent with other reports in the literature [ 24 , 25 ] .
the inconclusive fna report from the case reported by sousa et al . is consistent with the series reported by guy et al . who further reiterated the difficulty of getting adequate sample in 10% of cases where fna was used in the diagnosis of spindle cell lesions of the liver .
hence fna does not seem appropriate and adequate for the diagnosis of primary leiomyoma of the liver .
the average size of the tumour in this review is 8.7 cm ( range 230 ) .
the largest size of this tumour in the literature , 30 cm , was reported by belli et al . in a 67-year - old woman who presented with abdominal mass .
primary leiomyoma of the liver has been described in the literature as a solitary firm , white , fasciculate , and well demarcated tumour which is consistent with the findings of this review [ 4 , 10 , 19 , 39 ] .
one author reported a case of primary leiomyoma of the liver with two sharply delineated tumours but other cases in the review have been reported as solitary tumours .
the shape has been reported to be roughly spherical to oval ( figure 3(a ) ) .
histological review of tissue sections and specimens is absolutely important because the distinction between benign and malignant smooth muscle tumours of the gastrointestinal tract on imaging is not very clear .
the cellular architecture has been variably described as multiple interlacing bundles of uniform spindle cells homogeneous pattern of interlacing bundles of uniform elongate cells with a plump spindle shaped , whirling bundles of well differentiated regular spindle shaped smooth muscle cells [ 2 , 12 ] , and highly cellular population of spindle cells arranged in interwoven fascicles ( figure 3(b ) ) .
high density reticular fibres with a peripheral collagen rich zone which indicates expanding growth have been reported [ 20 , 24 ] .
electron microscopy findings suggest tumour cells with well - defined basement membrane , scattered electron dense condensations in the plasma membrane , abundant glycogen , and pinocytotic vesicles and cytoplasmic filaments .
central [ 19 , 25 ] and focal areas of necrosis have been described in the case reports . however it was not stated in the case reports if the necrosis were coagulative in nature .
primary leiomyomas of the liver have been largely reported without evidence of mitotic changes except for few case reports which variously reported scarce , low , and rare mitoses [ 2 , 4 , 6 , 12 , 18 , 20 , 21 , 24 ] .
histological features suggestive of malignancy include prominent cellular atypia with nuclear pleomorphism , large size , presence of infiltration , dense cellularity , degenerative changes , areas of coagulative necrosis , and increased mitotic rates ( more than 1/10 hpf ) [ 1 , 12 , 18 , 19 ] .
mitotic index as defined by the number of mitoses per specified high power field was not documented for some of the case reports [ 2 , 12 , 21 ] .
and hawkins et al . reported mitotic count of less than 1/10 hpf ( high power field ) .
and sclabas et al . reported a mitotic count of 1/50 hpf and less than 1/20 hpf , respectively .
various mitotic indexes have been suggested as a cut off criteria for leiomyosarcoma in nonuterine smooth muscle tumours .
ranchod and kempson suggested five or more mitoses/10 hpf while between 510/50 hpf has been suggested by some authors [ 4446 ] .
the use of mitotic index in a uniform manner for all cases reported in the future is needful to ensure unequivocal diagnosis especially in a case reported with mild cellular atypia in the presence of mitoses which may suggest a distinct possibility of malignancy .
the cells in the case reports reviewed have been reported to be positive to alpha smooth muscle actin ( figure 3(c ) ) .
some of the cells also stained positive to desmin ( figure 3(d ) ) [ 2 , 24 ] and vimentin .
there is lack of expression of cd 34 [ 20 , 39 ] , cd 68 , vimentin hmb-45 , s100 [ 19 , 20 ] , cd 117 , and dog1 .
ultrastructural studies have been reported to show filaments , some dense bodies , and a few pinocytic vesicles .
cd 117 , cd34 , and dog1 are markers of gastrointestinal stromal tumours ( gist ) and hmb-45 reactivity suggests angiomyolipoma [ 5 , 36 , 47 ] .
surgical resection of the tumour appears to be both diagnostic and curative in this review of the literature .
the prognosis of this tumour appears to be excellent without evidence of disease during the follow - up of the cases .
the average follow - up of the cases in this review is 33 months ( range 4108 ) .
this paper to the best of the knowledge of the author is the largest review of case reports of primary leiomyoma of the liver in the literature .
primary leiomyoma of the liver is a very rare tumour with a complex pathogenesis which remains largely unknown .
the diagnosis of the primary leiomyoma of the liver must meet a set of diagnostic criteria proposed by hawkins et al . which ensures the cells are leiomyocytes and the exclusion of coexisting leiomyoma from other sites of the body .
this should include investigations like oesophagogastroduodenoscopy , colonoscopy , imaging techniques like ct scans and mri , and a thorough exploration during surgery .
primary leiomyoma of the liver should be considered as a differential diagnosis of liver lesions with or without immunosuppression .
multiple imaging techniques do not allow for a tissue specific diagnosis ; hence histological review of the tissue specimen and immunohistochemical stains are imperative for diagnosis .
Output:
| context . primary leiomyoma of the liver is a rare tumour with uncertain pathogenesis with similar presentation with other tumours of the liver .
little is known about its clinical course .
objectives . to review the literature for case reports of primary leiomyoma of the liver . methods .
extensive literature search was carried out for case reports of primary leiomyoma of the liver .
results . a total of 36 cases of primary leiomyoma of the liver were reviewed .
the mean age of presentation is 43 years with slight female sex affectation ; females accounted for 55.6% of the cases reported in the literature .
the average size of the tumour is 8.7 cm .
34.4% of the cases reviewed were incidental finding with the mean follow - up time of 33 months with most cases reporting no evidence of disease .
conclusions .
primary leiomyoma of the liver is very rare tumour with complex pathogenesis which remains largely unknown .
imaging of the tumour does not allow for a tissue specific diagnosis ; hence histological review of the tissue specimen and immunohistochemical stains are imperative for diagnosis .
surgical resection is both diagnostic and curative .
the diagnosis of primary leiomyoma of the liver should be considered as a differential in the management of liver tumours . |
PubmedSumm6513 | ***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 following mice strains were used : c57bl / j ins2 , which display elevated glucose at 46 weeks of age ; b6 ( c57bl/6 ) ( a gift from dr . s. smith , georgia health sciences university ) and db / db ( bks cg - dock7 m ) , which display elevated glucose at 48 weeks of age ; and blks ( c57blks / j ) ( diabetes and obesity discovery institute , georgia health sciences university ) . blood glucose was measured after a tail clip using accu - chek aviva ( roche , worldwide ) .
fibroblasts were obtained through trypsin digestion of mouse ears for 1 h and cultured in dulbecco s modified eagle s medium ( dmem ) ( invitrogen , carlsbad , ca ) from rage - deficient ( rage , n = 3 ) ( 17 ) , c57bl / j ins2 ( n = 4 ) , and b6 ( n = 4 ) mice . all protocols for animal use and euthanasia were reviewed and approved by the animal use committee at georgia health sciences university and were in accordance with national institutes of health guidelines .
solei were dissected from mice , secured to 35-mm culture dishes by a drop of new - skin ( medtech , irvington , ny ) liquid bandage , and kept ( < 1 h ) in ice - cold tyrode solution : 128 mmol / l nacl , 4.7 mmol / l kcl , 1.36 mmol / l cacl2 , 20 mmol / l nahco3 , 0.36 mmol / l nah2po4 , 1 mmol / l mgcl2 , and 10 mmol / l glucose , ph 7.4 ( 18 ) . laser analysis was carried out in 37c tyrode solution containing 1.36 mmol / l cacl2 , or tyrode without added cacl2 .
fm 143 dye ( invitrogen ) , a membrane impermeant dye , was added ( 2.5 mol / l ) before laser injury ( 19 ) .
intact plasma membranes of healthy myocytes , highlighted by staining of fm dye , were targeted for laser injury using a two - photon laser scanning confocal microscope ( lsm 510 ; zeiss , thornwood , ny ) coupled with a 10-w argon / ti - sapphire laser ( spectra - physics lasers ) operated at 100% power , 100 iterations , with a 5 35 pixels bleach area .
fluorescence , associated with the injured domain of the myocyte , was measured in a 120-m diameter circular window centered on the myocyte injury site using zeiss lsm 510 software .
fluorescence measured before the injury was subtracted . after laser injury , myocyte contractions were often observed , moving fibers out of focus , and manual refocusing was used .
cultured cells were wounded in phosphate - buffered saline ( pbs ) containing 137.9 mmol / l nacl , 2.7 mmol / l kcl , 15.2 mmol / l na2hpo4 , 1.5 mmol / l kh2po4 , 1 mmol / l mgcl2 ( with or without 1.2 mmol / l ca ) ( sigma , st .
louis , mo ) , and 2.5 mol / l fm 143 or fm 464 ( invitrogen ) for injury .
the disruptions were made using 100% power and one laser iteration with a 15 15 pixels bleach area .
ins2 mice ( n = 9 ) with blood glucose levels > 600 mg / dl ( accu - chek hi ) and b6 mice ( n = 9 ) with blood glucose levels of 151.11 7.95 mg / dl were run on a treadmill set at a 15-degree decline as previously described ( 11 ) ( omnipacer treadmill lc4/m - mga / at ; accuscan instruments , columbus , oh ) .
these mice were subjected to a moderate downhill run of 10 m / min for 1 h. control mice remained in their cages ( n = 4/group ) .
after completion of the downhill run , all mice were injected with evan s blue dye ( ebd ) ( 10 mg ebd/1 ml pbs , 100 l/10 g body wt ; sigma ) ( 20 ) , and 24 h later , the quadriceps and gastrocnemius were excised , weighed , and frozen in o.c.t .
ebd stains albumin present within tissue , clearly highlighting the exterior of muscle fibers , while also staining albumin present within fibers that are no longer intact ( 16,20 ) .
cross sections were cut at a 10-m thickness and analyzed microscopically ( 10 magnification ) for ebd - positive fibers .
fluorescently labeled cells were scored per cross - section taken at four random muscle locations and averaged per muscle .
c2c12 , bs - c-1 , and hela cells were cultured in dmem , passaged twice weekly , and supplemented with glucose ( glucose at 5.5 mmol / l simulates a fasting blood glucose of 99 mg / dl , 7.5 mmol / l glucose represents fed blood glucose level of 135 mg / dl , and 30 mmol
/ l glucose elevated blood glucose level of 540 mg / dl ) or mannitol ( 21 ) and , where noted , treated with 1 mmol / l aminoguanidine ( amg ) ( sigma ) .
the 96-well plates of cells were subjected to scraping using a spring - loaded 96-well transfer device ( 22 ) .
this device was used in a circular motion to scrape cells off their substratum , therefore creating plasma membrane disruptions ( 23 ) .
survival in this population was assessed using a live / dead viability / cytotoxicity kit according to the manufacturer s instructions ( molecular probes , carlsbad , ca ) .
the live / dead fluorescence ratio , calcein acetoxymethyl ester ( excitation / emission 495 nm/515 nm ) to ethidium homodimer-1 ( excitation / emission 495 nm/635 nm ) ratio , was determined after 1 h of incubation using a fluorescent plate reader ( flx800 ; biotek , winooski , vt ) . alternatively ,
after replating cells from the multiwell scrape assay , fresh dmem was added to each well .
a dmem rinse was used to remove dead nonadherent cells from the plate after 4 h at 37c .
the mtt ( 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide ) assay was then performed using the methods previously described ( 24 ) .
the cells surviving the scrape injury were compared with uninjured control populations to calculate percent survival .
a rage construct was produced by subcloning the full - length human rage gene into the enhanced green fluorescent protein ( pegfp)-n1 vector to generate pegfr - n1-rage ( egfp is fused to the cooh terminus of rage ) .
bs - c-1 cells were transfected with 1 g pefgp - n1-rage using lipofectamine ( invitrogen ) .
cells were treated for 20 h with 5 mmol / l of age - modified bsa ( age - bsa ) ( sigma ) 4 h after transfection .
microscope images of laser injury were taken using a 40 ir - acroplan lens , 0.8 numerical aperture ; a zeiss axioplan 2 microscope ; and lsm 510 software for image analysis .
microscope images of ebd were taken using a 10 plan - neofluar lens , 0.3 numerical aperture ; a zeiss axioplan 2 microscope ; and a zeiss axiocam high - resolution camera .
comparisons were made with prism 5.0 software using repeated - measures anova and tukey post - analysis tests for significance .
a student t test was used to determine the difference between muscle diameters ( two - tailed ) , mouse weights ( two - tailed ) , and decreased muscle weights ( one - tailed ) .
for all analysis , p < 0.05 was considered to be significant . in text and graphs ,
the following mice strains were used : c57bl / j ins2 , which display elevated glucose at 46 weeks of age ; b6 ( c57bl/6 ) ( a gift from dr . s. smith , georgia health sciences university ) and db / db ( bks cg - dock7 m ) , which display elevated glucose at 48 weeks of age ; and blks ( c57blks / j ) ( diabetes and obesity discovery institute , georgia health sciences university ) . blood glucose was measured after a tail clip using accu - chek aviva ( roche , worldwide ) .
fibroblasts were obtained through trypsin digestion of mouse ears for 1 h and cultured in dulbecco s modified eagle s medium ( dmem ) ( invitrogen , carlsbad , ca ) from rage - deficient ( rage , n = 3 ) ( 17 ) , c57bl / j ins2 ( n = 4 ) , and b6 ( n = 4 ) mice . all protocols for animal use and euthanasia were reviewed and approved by the animal use committee at georgia health sciences university and were in accordance with national institutes of health guidelines .
solei were dissected from mice , secured to 35-mm culture dishes by a drop of new - skin ( medtech , irvington , ny ) liquid bandage , and kept ( < 1 h ) in ice - cold tyrode solution : 128 mmol / l nacl , 4.7 mmol / l kcl , 1.36 mmol / l cacl2 , 20 mmol / l nahco3 , 0.36 mmol / l nah2po4 , 1 mmol / l mgcl2 , and 10 mmol / l glucose , ph 7.4 ( 18 ) . laser analysis was carried out in 37c tyrode solution containing 1.36 mmol / l cacl2 , or tyrode without added cacl2 .
fm 143 dye ( invitrogen ) , a membrane impermeant dye , was added ( 2.5 mol / l ) before laser injury ( 19 ) .
intact plasma membranes of healthy myocytes , highlighted by staining of fm dye , were targeted for laser injury using a two - photon laser scanning confocal microscope ( lsm 510 ; zeiss , thornwood , ny ) coupled with a 10-w argon / ti - sapphire laser ( spectra - physics lasers ) operated at 100% power , 100 iterations , with a 5 35 pixels bleach area .
fluorescence , associated with the injured domain of the myocyte , was measured in a 120-m diameter circular window centered on the myocyte injury site using zeiss lsm 510 software .
fluorescence measured before the injury was subtracted . after laser injury , myocyte contractions were often observed , moving fibers out of focus , and manual refocusing was used .
cultured cells were wounded in phosphate - buffered saline ( pbs ) containing 137.9 mmol / l nacl , 2.7 mmol / l kcl , 15.2 mmol / l na2hpo4 , 1.5 mmol / l kh2po4 , 1 mmol / l mgcl2 ( with or without 1.2 mmol / l ca ) ( sigma , st .
louis , mo ) , and 2.5 mol / l fm 143 or fm 464 ( invitrogen ) for injury .
the disruptions were made using 100% power and one laser iteration with a 15 15 pixels bleach area .
ins2 mice ( n = 9 ) with blood glucose levels > 600 mg / dl ( accu - chek hi ) and b6 mice ( n = 9 ) with blood glucose levels of 151.11 7.95 mg / dl were run on a treadmill set at a 15-degree decline as previously described ( 11 ) ( omnipacer treadmill lc4/m - mga / at ; accuscan instruments , columbus , oh ) .
these mice were subjected to a moderate downhill run of 10 m / min for 1 h. control mice remained in their cages ( n = 4/group ) .
after completion of the downhill run , all mice were injected with evan s blue dye ( ebd ) ( 10 mg ebd/1 ml pbs , 100 l/10 g body wt ; sigma ) ( 20 ) , and 24 h later , the quadriceps and gastrocnemius were excised , weighed , and frozen in o.c.t .
ebd stains albumin present within tissue , clearly highlighting the exterior of muscle fibers , while also staining albumin present within fibers that are no longer intact ( 16,20 ) .
cross sections were cut at a 10-m thickness and analyzed microscopically ( 10 magnification ) for ebd - positive fibers .
fluorescently labeled cells were scored per cross - section taken at four random muscle locations and averaged per muscle .
c2c12 , bs - c-1 , and hela cells were cultured in dmem , passaged twice weekly , and supplemented with glucose ( glucose at 5.5 mmol / l simulates a fasting blood glucose of 99 mg / dl , 7.5 mmol / l glucose represents fed blood glucose level of 135 mg / dl , and 30 mmol / l glucose elevated blood glucose level of 540 mg / dl ) or mannitol ( 21 ) and , where noted , treated with 1 mmol / l aminoguanidine ( amg ) ( sigma ) .
the 96-well plates of cells were subjected to scraping using a spring - loaded 96-well transfer device ( 22 ) .
this device was used in a circular motion to scrape cells off their substratum , therefore creating plasma membrane disruptions ( 23 ) .
survival in this population was assessed using a live / dead viability / cytotoxicity kit according to the manufacturer s instructions ( molecular probes , carlsbad , ca ) .
the live / dead fluorescence ratio , calcein acetoxymethyl ester ( excitation / emission 495 nm/515 nm ) to ethidium homodimer-1 ( excitation / emission 495 nm/635 nm ) ratio , was determined after 1 h of incubation using a fluorescent plate reader ( flx800 ; biotek , winooski , vt ) . alternatively ,
after replating cells from the multiwell scrape assay , fresh dmem was added to each well .
a dmem rinse was used to remove dead nonadherent cells from the plate after 4 h at 37c .
the mtt ( 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide ) assay was then performed using the methods previously described ( 24 ) .
the cells surviving the scrape injury were compared with uninjured control populations to calculate percent survival .
a rage construct was produced by subcloning the full - length human rage gene into the enhanced green fluorescent protein ( pegfp)-n1 vector to generate pegfr - n1-rage ( egfp is fused to the cooh terminus of rage ) .
bs - c-1 cells were transfected with 1 g pefgp - n1-rage using lipofectamine ( invitrogen ) .
cells were treated for 20 h with 5 mmol / l of age - modified bsa ( age - bsa ) ( sigma ) 4 h after transfection .
microscope images of laser injury were taken using a 40 ir - acroplan lens , 0.8 numerical aperture ; a zeiss axioplan 2 microscope ; and lsm 510 software for image analysis .
microscope images of ebd were taken using a 10 plan - neofluar lens , 0.3 numerical aperture ; a zeiss axioplan 2 microscope ; and a zeiss axiocam high - resolution camera .
comparisons were made with prism 5.0 software using repeated - measures anova and tukey post - analysis tests for significance . a student t test was used to determine the difference between muscle diameters ( two - tailed ) , mouse weights ( two - tailed ) , and decreased muscle weights ( one - tailed ) . for all analysis , p <
to directly assess repair in the diabetic skeletal muscle environment , we used a novel in situ assay .
the intact solei of mice were placed in physiological saline containing a fluorescent dye , fm 143 , which strongly stains the plasma membrane boundary only of intact cells . after laser disruption of the plasma membrane ,
fm 143 diffuses into the cytosol through the disruption site and begins to fluorescently stain the internal membrane . in the presence of calcium ( ca ) ,
membrane repair is activated , slowing dye entry into the cytosol and consequent staining of internal membranes ( supplementary movie 1 ) .
a hot spot of fluorescence staining , the result of initial dye entry , marks the injury throughout the experiment . in the absence of ca
, membrane repair fails and the internal cellular compartments begin to saturate with dye , a process that continues throughout the 445-s time course ( supplementary movie 2 ) . because of the contractions of the injured myocyte , refocusing is frequently necessary , so that measurement is centered on the initial disruption site .
however , with this maneuver , fluorescence within the cell can be monitored and quantitated over time surrounding the disruption site .
two diabetic mouse models , c57bl / j ins2 ( ins2 ) with type 1 diabetes and bks cg - dock7 m ( db / db ) with type 2 diabetes , were assessed using this in situ laser assay . in muscle from c57bl/6 ( b6 ) and
c57blks / j ( blks ) control mice , laser injured in the presence of ca , a hot spot of fm 143 appeared at the membrane disruption site , but widespread staining of internal membrane was not observed , indicating repair had occurred ( fig . 1a , control b6 + ca , 445 s ; and supplementary movie 3 ) .
however , when ca was absent , control fibers displayed continuous cytosolic filling with fm 143 , characteristic of failed membrane repair ( fig .
1a , control b6 ca ) . strikingly , in both diabetic models , dye entered continuously into diabetic fibers , even when ca was present , indicating repair failed to occur ( fig .
1a , type 1 ins2 + ca ; and supplementary movies 4 and 5 ) .
1b : all fibers initially displayed similar dye uptake kinetics in the presence and absence of ca , indicating the size of the disruption made was equivalent .
however , at time points thereafter ( 375 s for the ins2 and 175 s for the db / db ) , significantly more dye uptake , compared with wild - type controls , in the presence of ca , was recorded in solei from both diabetic models .
in fact , measured dye uptake in diabetic myocytes was indistinguishable , whether ca was present or absent .
thus , using a highly sensitive in situ assay , we show that ca - dependent muscle membrane repair is deficient in both type 1 and type 2 diabetes mouse models .
a : a myocyte within the soleus muscle of a wild - type ( control b6 , top two rows ) and type 1 diabetic ( type 1 ins2 , bottom two rows ) mouse was imaged before ( 0 s ) and after membrane irradiation with an infrared laser ( arrow indicates injury site ) in the presence of ca or its absence .
repair ( control b6 + ca ) impedes further dye uptake and confines the resultant fluorescence to a hot spot at the site of injury . failed repair ( control b6 ca , type 1 ins2 ca , and type 1 ins2 + ca ) results in a sustained filling of the entire fiber with dye .
b : fluorescence signal was monitored over time to determine uptake of dye by myocytes from diabetic and control mice .
the red circle indicates the time point where the first significant difference of p < 0.05 is observed ( compared with all conditions ) .
* p < 0.01 ; myofibers injured , n = 25 for b6 + ca , n = 25 for b6 -ca , n = 35 for ins2 + ca , n = 30 for ins ca , n = 47 for blks + c ,
n = 45 for blks ca , n = 50 for db / db + ca , and n = 49 for db / db ca
( a high - quality digital representation of this figure is available in the online issue . ) images obtained while performing the in situ laser assay suggested that there might be a size difference between normal and diabetic fibers .
decreased fiber diameter was measured in both the soleus and quadriceps of diabetic mice , and ins2 mice also displayed significantly decreased body weight and muscle mass aged 67.5 months ( supplementary fig .
1 ) . these morphological changes confirm previous findings ( 25,26 ) that diabetes , as expected , negatively affected the skeletal muscle in these mouse models .
plasma membrane disruptions are induced in vivo in muscle undergoing eccentric contractions , such as those produced by downhill running ( 11 ) . to determine
if membrane repair fails at a greater rate in diabetic mice during eccentric contraction - induced injury , we monitored myocyte permeability to ebd . ebd is a fluorescent dye that enters only into cells lacking an intact plasma membrane barrier and is effective at identifying injured muscle fibers without the presence of a counter - stain ( 16,20 ) .
we injected this dye into mice after running , so that myofibers that suffered a disruption and failed to repair would be labeled .
as expected , in both normal and diabetic mice , running induced an increase in the number of ebd - positive fibers .
however , running induced a significantly higher number of ebd - positive fibers in the diabetic mice ( fig .
a : paired transmission and fluorescence micrographs showing ebd - labeled myofibers ( arrows ) in the gastrocnemius muscle from diabetic ( ins2 ) and control ( ctl ) ( b6 ) mice that run downhill for 60 min and then are injected with the ebd tracer .
b : the number of ebd myofibers counted from such micrographs in the gastrocnemius and quadriceps muscles of diabetic ins2 and control b6 mice .
data are presented as the mean sem . * p < 0.05 ; n = 5 mice for the run groups and 4 mice for the not run groups
( a high - quality digital representation of this figure is available in the online issue . ) thus , both our in situ and in vivo measurements strongly support the hypothesis that membrane repair fails in diabetes .
the diabetic environment in vivo is a complicated one , in which elevated blood glucose is just one pathophysiological element . to test whether glucose elevation alone is sufficient to induce a repair defect , we used an in vitro model mimicking the blood glucose levels found in our diabetic mouse models ( supplementary table 1 ) .
c2c12 cells , a skeletal muscle myocyte culture model , were assessed for membrane repair after growth for 18 weeks in medium containing normal glucose ( 7.5 mmol / l ) , elevated glucose ( 30 mmol / l ) , or mannitol ( 30 mmol / l ) . after 1 week of elevated glucose exposure , there was no qualitative change in repair ( for example , dye entry pattern ) ( fig .
3a , 1 week + ca all conditions ; and supplementary movie 6 ) .
however , after 8 weeks of high glucose exposure , dye entry after laser injury was clearly elevated , relative to the normal glucose and mannitol controls ( fig . 3a , 8 weeks n gluc + ca and man + ca ) , indicating an inability to repair ( fig .
thus , prolonged exposure to high glucose is required for inducing a repair defect , a finding that is not compatible with other short - term responses , such as induction of insulin resistance .
a : c2c12 myoblasts were cultured in medium with 7.5 mmol / l glucose ( n gluc ) , 30 mmol / l glucose ( h gluc ) , or iso - osmolar control 30 mmol / l mannitol ( man ) and then subject to laser analysis of repair ( arrows indicate injury site ) at 1 or 8 weeks of exposure .
the interval ( seconds ) postinjury is indicated . only cells grown in 30 mmol / l glucose for 8 weeks ( h gluc + ca )
b : dye uptake , fluorescence , measured within cells over time after injury . after 1 week of exposure to high glucose
( left panel ) , all cells displayed calcium - dependent repair with no significant difference in dye uptake between groups . by contrast , cells cultured for 8 weeks in high glucose ( right panel ) showed a significant increase in dye uptake compared with normal glucose and mannitol controls .
* p < 0.05 ; 1 week , n = 15 for n gluc + ca , n = 14 for h gluc + ca , n = 13 for man + ca , and n = 17 for n gluc ca ; 8 weeks , n = 26 for n gluc + ca , n = 30 for h gluc + ca , n = 28 for man + ca , and n = 15 for n gluc ca . scale bar , 50 m and 40 magnification .
( a high - quality digital representation of this figure is available in the online issue . ) to confirm that this glucose - induced repair defect was not limited to laser - generated disruptions , adherent c2c12 cells were scraped to mechanically induce membrane disruptions ( 23 ) .
consistent with the laser assay , there was no detectable difference in survival between treatment groups after 2 weeks of high glucose exposure ( fig . 4 , 2 weeks )
however , after 8 weeks of elevated glucose , cells displayed a significant decrease in survival when compared with those grown in normal glucose or mannitol ( fig .
4 , 8 weeks h gluc ) . thus , using an independent method for inducing membrane disruptions and for monitoring repair failure , we confirmed that high glucose leads to the development of a membrane repair defect .
/ l glucose ( n gluc ) , 30 mmol / l glucose ( h gluc ) , or iso - osmolar control 30 mmol / l mannitol ( man ) and then scraped from 96-well plates .
no significant differences were demonstrated after 2 weeks of treatment . however , 8 weeks of high glucose treatment decreased survival as determined by both assays .
* p < 0.01 ; n = 24 wells for each condition . to determine if other cell types develop a membrane repair defect after high glucose exposure , we applied the above analysis to bs - c-1 ( monkey kidney epithelial ) and hela ( human cervical ) cells .
as was the case for c2c12 myoblasts , bs - c-1 cells developed a repair deficiency only after 8 weeks of high glucose treatment ( fig .
bs - c-1 and hela survival of the scraping injury was also significantly decreased after 8 weeks of high glucose exposure , compared with cells grown in normal glucose or mannitol ( supplementary fig .
this glucose - induced membrane repair defect remained even after cells were returned to a low glucose medium for over a week ( fig .
additionally , fibroblasts obtained from diabetic ( ins2 ) mice also displayed a membrane repair defect after culturing in normal glucose medium for 1 week ( supplementary fig .
2b , ins2 ) . an epithelium - derived cell line , bs - c-1 , also develops repair failure in high glucose , and this defect is not readily reversible .
a : bs - c-1 cells were cultured for 8 weeks in 7.5 mmol / l glucose ( n gluc ) , 30 mmol / l glucose ( h gluc ) , or iso - osmolar control 30 mmol / l mannitol ( man ) . laser analysis revealed that cells cultured in high glucose displayed a significant increase in dye uptake when compared with normal glucose and mannitol .
b : bs - c-1 cells were cultured for 10 weeks in h gluc and then switched to l gluc ( 5.5 mmol / l glucose ) for 10 days ( h gluc / l gluc ) , or cells were cultured for 11 weeks in l gluc or h gluc only . laser analysis determined that the high glucose membrane repair defect remained 1 week after switching to low glucose ( h gluc / l gluc ) .
0.01 ; 2 weeks , n = 18 for n gluc + ca , n = 14 for h gluc + ca , n = 12 for man + ca , and n = 13 for h gluc ca ; 10 weeks , n = 14 for l gluc , n = 16 for h gluc , and n = 15 for h gluc / l gluc .
thus , our in vitro analysis revealed that the membrane repair defect is glucose induced , not exclusive to skeletal muscle cells , and does not appear to be readily reversible .
one well - established effect of elevated blood glucose is the production of ages , thought to contribute to the development of chronic diabetes complications ( 27,28 ) .
numerous studies ( 29,30 ) have detected age generation in vitro as soon as 48 h after initiating high glucose incubation . to test if this age production is required for the development of the membrane repair defect , we simultaneously exposed bs - c-1 cells to elevated glucose and amg , a potent inhibitor of age formation and accumulation ( 31 ) .
as expected , after 8 weeks of high glucose treatment in the absence of amg , membrane repair was defective ( fig .
however , this high glucose repair defect was completely eliminated by cotreatment with amg ( fig .
age / rage interaction is responsible for the repair defect . a : bs - c-1 cells were cultured in 30 mmol / l glucose supplemented with or without 1 mmol / l amg ( h gluc amg or h gluc ) , or 30 mmol / l mannitol ( man ) for 8 weeks .
cells exposed to high glucose alone showed significantly increased ( * ) dye uptake when compared with mannitol controls .
b : rage - deficient fibroblasts ( rage ) were cultured for 12 weeks in 30 mmol / l glucose ( h gluc ) , 5.5 mmol / l glucose ( l gluc ) , or 30 mmol / l mannitol ( man ) .
rage cells exposed to high glucose and injured in the presence of calcium ( h gluc + ca ) did not exhibit a significant increase in dye uptake compared with controls ( l gluc + ca and man + ca ) .
c : bs - c-1 cells were transfected with a rage - egfp expression vector ( pegfp - n1-rage ) .
cells displaying egfp fluorescence ( fl rage ) , and as controls , nonfluorescent cells in the same culture ( nf ) , were selected for laser analysis of repair .
one culture was exposed to 5 mmol / l age - bsa , and the other was not .
laser analysis showed membrane repair of fluorescent cells ( fl rage ) to be indistinguishable from nonfluorescent controls ( nf ) in cultures not exposed to age - bsa .
however , fluorescent cells treated with age ( fl rage age ) showed a significant ( * * ) elevation in dye uptake when compared with cells not treated with age , comparable to the dye uptake seen in cells wounded without calcium ( ca ) .
d : bs - c-1 cells were treated or not with 1 or 5 mmol / l age - bsa for 3 days before laser injury .
dye uptake was found to be significantly ( * ) greater for cells treated with age - bsa than cells left untreated and resembled the lack of repair for cells injured in the absence of ca ( ca ) .
bs - c-1 : n = 14 cells for man , n = 12 for h gluc , and n = 12 for h gluc amg
. fibroblasts : n = 23 cells for l gluc + ca , n = 23 for h gluc + ca , n = 24 for man + ca , and n = 19 for l gluc ca . transfected : n = 12 cells for nf , n = 9 for nf age , n = 10 for fl rage , n = 10 for fl rage age , and n = 15 for ca .
n = 21 cells for + ca , n = 18 for ca , n = 22 for 1 mmol / l age , and n = 17 for 5 mmol / l age .
age potently binds to a cell surface rage ( 27,28 ) , which in turn stimulates increased expression of this receptor and is hypothesized to contribute to the pathophysiology of diabetes ( 28,32 ) . to test if rage is implicated in the development of the membrane repair defect , we cultured rage - deficient cells ( rage ) in high glucose .
after 12 weeks of elevated glucose exposure , rage cells did not display the drastic increase in dye uptake , as previously determined in other cells treated to high glucose ( fig .
to further test the involvement of rage in promoting repair failure , we transfected bs - c-1 cells with an expression vector ( pegfp - n1-rage , where egfp is fused with the cooh terminus of rage ) to force rage expression .
cells that were successfully transfected ( as indicated by egfp - derived fluorescence ) were selected for laser injury .
dye entry kinetics into these rage - expressing cells were indistinguishable from nonfluorescent control cells in the same culture ( fig .
however , when the mixed culture of egfp - positive and -negative cells were incubated with age - bsa , fluorescent ( egfp - positive ) cells displayed significantly enhanced dye entry relative to nonfluorescent cells and also relative to fluorescent cells not exposed to age - bsa ( fig .
thus , rage expression alone is not sufficient for inducing membrane repair deficiency in cultured cells , but rage binding of age is clearly implicated in defective membrane repair .
we noticed in these experiments a slight but not statistically significant increase in dye entry into the nonfluorescent cells exposed to age - bsa for 24 h ( fig .
therefore , we investigated further whether age exposure by itself could negatively influence membrane repair .
when we increased the exposure level of cell to age - bsa , we found that dye entry was significantly elevated ( fig .
thus , age formation , and not some other metabolic change induced by high glucose exposure , is responsible for repair failure , and rage binding of age is identified as one mechanism by which age exerts its deleterious effect .
to directly assess repair in the diabetic skeletal muscle environment , we used a novel in situ assay .
the intact solei of mice were placed in physiological saline containing a fluorescent dye , fm 143 , which strongly stains the plasma membrane boundary only of intact cells . after laser disruption of the plasma membrane ,
fm 143 diffuses into the cytosol through the disruption site and begins to fluorescently stain the internal membrane . in the presence of calcium ( ca ) ,
membrane repair is activated , slowing dye entry into the cytosol and consequent staining of internal membranes ( supplementary movie 1 ) .
a hot spot of fluorescence staining , the result of initial dye entry , marks the injury throughout the experiment . in the absence of ca
, membrane repair fails and the internal cellular compartments begin to saturate with dye , a process that continues throughout the 445-s time course ( supplementary movie 2 ) . because of the contractions of the injured myocyte , refocusing is frequently necessary , so that measurement is centered on the initial disruption site .
however , with this maneuver , fluorescence within the cell can be monitored and quantitated over time surrounding the disruption site .
two diabetic mouse models , c57bl / j ins2 ( ins2 ) with type 1 diabetes and bks cg - dock7 m ( db / db ) with type 2 diabetes , were assessed using this in situ laser assay . in muscle from c57bl/6 ( b6 ) and
c57blks / j ( blks ) control mice , laser injured in the presence of ca , a hot spot of fm 143 appeared at the membrane disruption site , but widespread staining of internal membrane was not observed , indicating repair had occurred ( fig . 1a , control b6 + ca , 445 s ; and supplementary movie 3 ) .
however , when ca was absent , control fibers displayed continuous cytosolic filling with fm 143 , characteristic of failed membrane repair ( fig .
1a , control b6 ca ) . strikingly , in both diabetic models , dye entered continuously into diabetic fibers , even when ca was present , indicating repair failed to occur ( fig .
1a , type 1 ins2 + ca ; and supplementary movies 4 and 5 ) .
1b : all fibers initially displayed similar dye uptake kinetics in the presence and absence of ca , indicating the size of the disruption made was equivalent .
however , at time points thereafter ( 375 s for the ins2 and 175 s for the db / db ) , significantly more dye uptake , compared with wild - type controls , in the presence of ca , was recorded in solei from both diabetic models .
in fact , measured dye uptake in diabetic myocytes was indistinguishable , whether ca was present or absent .
thus , using a highly sensitive in situ assay , we show that ca - dependent muscle membrane repair is deficient in both type 1 and type 2 diabetes mouse models .
a : a myocyte within the soleus muscle of a wild - type ( control b6 , top two rows ) and type 1 diabetic ( type 1 ins2 , bottom two rows ) mouse was imaged before ( 0 s ) and after membrane irradiation with an infrared laser ( arrow indicates injury site ) in the presence of ca or its absence .
repair ( control b6 + ca ) impedes further dye uptake and confines the resultant fluorescence to a hot spot at the site of injury . failed repair ( control b6 ca , type 1 ins2 ca , and type 1 ins2 + ca ) results in a sustained filling of the entire fiber with dye .
b : fluorescence signal was monitored over time to determine uptake of dye by myocytes from diabetic and control mice .
the red circle indicates the time point where the first significant difference of p < 0.05 is observed ( compared with all conditions ) .
* p < 0.01 ; myofibers injured , n = 25 for b6 + ca , n = 25 for b6 -ca , n = 35 for ins2 + ca , n = 30 for ins ca , n = 47 for blks + c ,
n = 45 for blks ca , n = 50 for db / db + ca , and n = 49 for db / db ca
( a high - quality digital representation of this figure is available in the online issue . ) images obtained while performing the in situ laser assay suggested that there might be a size difference between normal and diabetic fibers .
decreased fiber diameter was measured in both the soleus and quadriceps of diabetic mice , and ins2 mice also displayed significantly decreased body weight and muscle mass aged 67.5 months ( supplementary fig .
1 ) . these morphological changes confirm previous findings ( 25,26 ) that diabetes , as expected , negatively affected the skeletal muscle in these mouse models .
plasma membrane disruptions are induced in vivo in muscle undergoing eccentric contractions , such as those produced by downhill running ( 11 ) . to determine
if membrane repair fails at a greater rate in diabetic mice during eccentric contraction - induced injury , we monitored myocyte permeability to ebd . ebd is a fluorescent dye that enters only into cells lacking an intact plasma membrane barrier and is effective at identifying injured muscle fibers without the presence of a counter - stain ( 16,20 ) .
we injected this dye into mice after running , so that myofibers that suffered a disruption and failed to repair would be labeled .
as expected , in both normal and diabetic mice , running induced an increase in the number of ebd - positive fibers .
however , running induced a significantly higher number of ebd - positive fibers in the diabetic mice ( fig .
a : paired transmission and fluorescence micrographs showing ebd - labeled myofibers ( arrows ) in the gastrocnemius muscle from diabetic ( ins2 ) and control ( ctl ) ( b6 ) mice that run downhill for 60 min and then are injected with the ebd tracer .
b : the number of ebd myofibers counted from such micrographs in the gastrocnemius and quadriceps muscles of diabetic ins2 and control b6 mice .
data are presented as the mean sem . * p < 0.05 ; n = 5 mice for the run groups and 4 mice for the not run groups
( a high - quality digital representation of this figure is available in the online issue . ) thus , both our in situ and in vivo measurements strongly support the hypothesis that membrane repair fails in diabetes .
the diabetic environment in vivo is a complicated one , in which elevated blood glucose is just one pathophysiological element . to test whether glucose elevation alone is sufficient to induce a repair defect , we used an in vitro model mimicking the blood glucose levels found in our diabetic mouse models ( supplementary table 1 ) .
c2c12 cells , a skeletal muscle myocyte culture model , were assessed for membrane repair after growth for 18 weeks in medium containing normal glucose ( 7.5 mmol / l ) , elevated glucose ( 30 mmol / l ) , or mannitol ( 30 mmol / l ) .
after 1 week of elevated glucose exposure , there was no qualitative change in repair ( for example , dye entry pattern ) ( fig .
3a , 1 week + ca all conditions ; and supplementary movie 6 ) .
however , after 8 weeks of high glucose exposure , dye entry after laser injury was clearly elevated , relative to the normal glucose and mannitol controls ( fig .
3a , 8 weeks n gluc + ca and man + ca ) , indicating an inability to repair ( fig .
thus , prolonged exposure to high glucose is required for inducing a repair defect , a finding that is not compatible with other short - term responses , such as induction of insulin resistance .
a : c2c12 myoblasts were cultured in medium with 7.5 mmol / l glucose ( n gluc ) , 30 mmol / l glucose ( h gluc ) , or iso - osmolar control 30 mmol / l mannitol ( man ) and then subject to laser analysis of repair ( arrows indicate injury site ) at 1 or 8 weeks of exposure . the interval ( seconds ) postinjury is indicated .
only cells grown in 30 mmol / l glucose for 8 weeks ( h gluc + ca ) were observed to fill with dye after laser injury in the presence of calcium .
b : dye uptake , fluorescence , measured within cells over time after injury . after 1 week of exposure to high glucose ( left panel ) , all cells displayed calcium - dependent repair with no significant difference in dye uptake between groups . by contrast , cells cultured for 8 weeks in high glucose ( right panel ) showed a significant increase in dye uptake compared with normal glucose and mannitol controls .
p < 0.05 ; 1 week , n = 15 for n gluc + ca , n = 14 for h gluc + ca , n = 13 for man + ca , and n = 17 for n gluc ca ; 8 weeks , n = 26 for n gluc + ca , n = 30 for h gluc + ca , n = 28 for man + ca , and n = 15 for n gluc ca . scale bar , 50 m and 40 magnification .
( a high - quality digital representation of this figure is available in the online issue . ) to confirm that this glucose - induced repair defect was not limited to laser - generated disruptions , adherent c2c12 cells were scraped to mechanically induce membrane disruptions ( 23 ) .
consistent with the laser assay , there was no detectable difference in survival between treatment groups after 2 weeks of high glucose exposure ( fig . 4 , 2 weeks ) .
however , after 8 weeks of elevated glucose , cells displayed a significant decrease in survival when compared with those grown in normal glucose or mannitol ( fig .
4 , 8 weeks h gluc ) . thus , using an independent method for inducing membrane disruptions and for monitoring repair failure , we confirmed that high glucose leads to the development of a membrane repair defect .
c2c12 myoblasts were cultured for 2 or 8 weeks in 7.5 mmol / l glucose ( n gluc ) , 30 mmol / l glucose ( h gluc ) , or iso - osmolar control 30 mmol / l mannitol ( man ) and then scraped from 96-well plates .
however , 8 weeks of high glucose treatment decreased survival as determined by both assays .
data are presented as the mean sem . * p < 0.01 ; n = 24 wells for each condition . to determine if other cell types develop a membrane repair defect after high glucose exposure , we applied the above analysis to bs - c-1 ( monkey kidney epithelial ) and hela ( human cervical ) cells .
as was the case for c2c12 myoblasts , bs - c-1 cells developed a repair deficiency only after 8 weeks of high glucose treatment ( fig .
bs - c-1 and hela survival of the scraping injury was also significantly decreased after 8 weeks of high glucose exposure , compared with cells grown in normal glucose or mannitol ( supplementary fig .
this glucose - induced membrane repair defect remained even after cells were returned to a low glucose medium for over a week ( fig .
additionally , fibroblasts obtained from diabetic ( ins2 ) mice also displayed a membrane repair defect after culturing in normal glucose medium for 1 week ( supplementary fig .
2b , ins2 ) . an epithelium - derived cell line , bs - c-1 , also develops repair failure in high glucose , and this defect is not readily reversible .
/ l glucose ( n gluc ) , 30 mmol / l glucose ( h gluc ) , or iso - osmolar control 30 mmol
laser analysis revealed that cells cultured in high glucose displayed a significant increase in dye uptake when compared with normal glucose and mannitol .
b : bs - c-1 cells were cultured for 10 weeks in h gluc and then switched to l gluc ( 5.5 mmol / l glucose ) for 10 days ( h gluc / l gluc ) , or cells were cultured for 11 weeks in l gluc or h gluc only . laser analysis determined that the high glucose membrane repair defect remained 1 week after switching to low glucose ( h gluc / l gluc ) .
* p < 0.01 ; 2 weeks , n = 18 for n gluc + ca , n = 14 for h gluc + ca , n = 12 for man + ca , and n = 13 for h gluc ca ; 10 weeks , n = 14 for l gluc , n = 16 for h gluc , and n = 15 for h gluc / l gluc .
thus , our in vitro analysis revealed that the membrane repair defect is glucose induced , not exclusive to skeletal muscle cells , and does not appear to be readily reversible .
one well - established effect of elevated blood glucose is the production of ages , thought to contribute to the development of chronic diabetes complications ( 27,28 ) .
numerous studies ( 29,30 ) have detected age generation in vitro as soon as 48 h after initiating high glucose incubation . to test if this age production is required for the development of the membrane repair defect , we simultaneously exposed bs - c-1 cells to elevated glucose and amg , a potent inhibitor of age formation and accumulation ( 31 ) .
as expected , after 8 weeks of high glucose treatment in the absence of amg , membrane repair was defective ( fig .
however , this high glucose repair defect was completely eliminated by cotreatment with amg ( fig .
a : bs - c-1 cells were cultured in 30 mmol / l glucose supplemented with or without 1 mmol / l amg ( h gluc amg or h gluc ) , or 30 mmol / l mannitol ( man ) for 8 weeks .
cells exposed to high glucose alone showed significantly increased ( * ) dye uptake when compared with mannitol controls .
b : rage - deficient fibroblasts ( rage ) were cultured for 12 weeks in 30 mmol / l glucose ( h gluc ) , 5.5 mmol / l glucose ( l gluc ) , or 30 mmol / l mannitol ( man ) .
rage cells exposed to high glucose and injured in the presence of calcium ( h gluc + ca ) did not exhibit a significant increase in dye uptake compared with controls ( l gluc + ca and man + ca ) .
c : bs - c-1 cells were transfected with a rage - egfp expression vector ( pegfp - n1-rage ) .
cells displaying egfp fluorescence ( fl rage ) , and as controls , nonfluorescent cells in the same culture ( nf ) , were selected for laser analysis of repair .
one culture was exposed to 5 mmol / l age - bsa , and the other was not .
laser analysis showed membrane repair of fluorescent cells ( fl rage ) to be indistinguishable from nonfluorescent controls ( nf ) in cultures not exposed to age - bsa .
however , fluorescent cells treated with age ( fl rage age ) showed a significant ( * * ) elevation in dye uptake when compared with cells not treated with age , comparable to the dye uptake seen in cells wounded without calcium ( ca ) .
d : bs - c-1 cells were treated or not with 1 or 5 mmol / l age - bsa for 3 days before laser injury .
dye uptake was found to be significantly ( * ) greater for cells treated with age - bsa than cells left untreated and resembled the lack of repair for cells injured in the absence of ca ( ca ) .
bs - c-1 : n = 14 cells for man , n = 12 for h gluc , and n = 12 for h gluc amg
. fibroblasts : n = 23 cells for l gluc + ca , n = 23 for h gluc + ca , n = 24 for man + ca , and n = 19 for l gluc ca .
transfected : n = 12 cells for nf , n = 9 for nf age , n = 10 for fl rage , n = 10 for fl rage age , and n = 15 for ca .
n = 21 cells for + ca , n = 18 for ca , n = 22 for 1 mmol / l age , and n = 17 for 5 mmol / l age .
age potently binds to a cell surface rage ( 27,28 ) , which in turn stimulates increased expression of this receptor and is hypothesized to contribute to the pathophysiology of diabetes ( 28,32 ) . to test if rage is implicated in the development of the membrane repair defect , we cultured rage - deficient cells ( rage ) in high glucose .
after 12 weeks of elevated glucose exposure , rage cells did not display the drastic increase in dye uptake , as previously determined in other cells treated to high glucose ( fig .
this result indicates that rage is required for the glucose - induced repair defect . to further test the involvement of rage in promoting repair failure
, we transfected bs - c-1 cells with an expression vector ( pegfp - n1-rage , where egfp is fused with the cooh terminus of rage ) to force rage expression .
cells that were successfully transfected ( as indicated by egfp - derived fluorescence ) were selected for laser injury .
dye entry kinetics into these rage - expressing cells were indistinguishable from nonfluorescent control cells in the same culture ( fig .
however , when the mixed culture of egfp - positive and -negative cells were incubated with age - bsa , fluorescent ( egfp - positive ) cells displayed significantly enhanced dye entry relative to nonfluorescent cells and also relative to fluorescent cells not exposed to age - bsa ( fig .
thus , rage expression alone is not sufficient for inducing membrane repair deficiency in cultured cells , but rage binding of age is clearly implicated in defective membrane repair .
we noticed in these experiments a slight but not statistically significant increase in dye entry into the nonfluorescent cells exposed to age - bsa for 24 h ( fig .
therefore , we investigated further whether age exposure by itself could negatively influence membrane repair .
when we increased the exposure level of cell to age - bsa , we found that dye entry was significantly elevated ( fig .
thus , age formation , and not some other metabolic change induced by high glucose exposure , is responsible for repair failure , and rage binding of age is identified as one mechanism by which age exerts its deleterious effect .
the current study identifies a novel adverse effect of diabetes on skeletal muscle : we provide direct evidence that plasma membrane repair by myocytes is compromised in in vivo , in situ , and in vitro models .
diabetic myopathy , generally speaking , has been viewed as a consequence of underlying neuropathy ( 5,33 ) .
however , to our knowledge , there is no definitive evidence to suggest a causal relationship between diabetic neuropathy and myopathy .
one study found that muscle contractions induced in diabetic rats by sciatic nerve stimulation resulted in
focal ( limited domains of abnormal myofiber structure at the light microscope level ) muscle myocyte damage and elevated creatinine kinase levels ( 10 ) .
this result suggested that the diabetic condition could directly affect the contracting skeletal muscle myocyte .
what element of the diabetic environment might be detrimental and what exactly fails when the diabetic myocyte contracts remain open questions . using in vitro , in situ , and in vivo models ,
we demonstrate that elevated glucose results in defective plasma membrane repair and that , in diabetic mice , skeletal muscle myocytes are repair defective . in this study , using a novel in situ laser assay , we show that myofibers of both type 1 and type 2 diabetic mouse models display an inability to repair membrane disruptions .
neuropathy can not be implicated in this repair defect , since our analysis of isolated muscle is inherently independent of the nervous system functioning .
moreover , we use a vital dye ( ebd ) to show that repair of disruptions , induced by downhill running , is impaired in diabetic mice , indicating that the defect is not one unique to a laser injury , but one that arises under physiological conditions as well .
plasma membrane repair is a complex and dynamic cell survival response activated by influx of extracellular ca through the disruption .
this ca entry rapidly elicits homotypic vesicle - vesicle fusion in the cytoplasm surrounding the site of disruption ( 12,13,34 ) .
vesicle thus forms from cytoplasmic membranes , such as endosomes ( 35 ) , lysosomes ( 36 ) , enlargesomes ( 37 ) , and yolk granules ( 38 ) .
exocytotic annealing of this enlarging patch vesicle , also triggered by ca , to plasma membrane surrounding the injury site , restores membrane continuity ( 14,39 ) .
not unexpectedly , these include known universal components of membrane fusion , such as the soluble n - ethylmaleimide sensitive factor attachment protein receptor family members ( 12,40 ) and synaptotagmin ( 41 ) . also demonstrated to be required for successful repair are dysferlin ( 16 ) , annexins ( 42 ) , actin and myosin ( 43 ) , calpain ( 44 ) , and mitsugumin 53 ( 45 ) .
for the present work , it is important to also consider the heterogeneous array of membrane glycoproteins that decorate cell surfaces .
multivalent plant lectins that bind these surface carbohydrates can cross - link these membrane glycoproteins .
such lectin cross - linking potently inhibits membrane repair , and it is the exocytotic step of repair that is blocked by lectins ( 46 ) .
this result suggested that age / rage interactions , which are elevated in diabetes , might be acting in an analogous fashion as an inhibitor of repair . in other words , rage binding and cross - linking of age ( 46 ) might be responsible for the repair defect in diabetic mice .
we report here the numerous tests of the possibility that age / rage interactions are responsible for the repair defect in diabetes .
our in vitro model system shows that development of the membrane repair defect can be driven by a prolonged ( at least 8 weeks ) exposure to high glucose .
high glucose levels promote nonenzymatic cell surface hyperglycation of glycoproteins ( 47,48 ) ( e.g. , the production of age ) .
we show that the accumulation of ages is responsible for the membrane repair defect seen in cell culture : the glucose - induced defect was not detectable when age generation was prevented by the addition of amg to cell culture medium .
moreover , we show that age - bsa can , by virtue of its addition alone to culture medium , produces a repair defect in the absence of high glucose exposure .
finally , we show that cells expressing egfp - rage , in the absence of high glucose exposure , develop a repair defect , but only if age - bsa is added to the culture medium , and that rage - deficient cells do not develop a repair defect when exposed to elevated glucose . taken together
, these results strongly suggest that age and age / rage binding is involved in the development of the repair defect in diabetes .
whether inhibition by age / rage occurs by a mechanism analogous to that mediated by lectin cross - linking ( see above ) remains a question for further research .
normally produced at a relatively low rate under physiological conditions , reactive oxygen species are drastically elevated in diabetes ( 28 ) .
one explanation for this is that age / rage binding , elevated in diabetes , stimulates production of reactive oxygen species ( 49 ) .
another is that intracellular glucose can by itself increase production of superoxide radicals ( 1 ) .
we have recently found that reactive oxygen species strikingly inhibit repair in skeletal muscle and that prior antioxidant treatment can prevent this ( a.c.h .
thus , generation of reactive oxygen species in diabetes , whether by an age / rage - dependent or -independent mechanism , is a possible downstream mediator of membrane repair failure .
additionally , the high glucose environment induces a variety of alterations in the cell , some of which ( such as hyperlipidemia , with consequent changes in membrane lipid composition ) might influence the membrane fusion events of repair . in summary , in vitro and in vivo assays show that the diabetic environment induces in the skeletal muscle myocyte a plasma membrane repair defect .
although it is conceivable that this repair defect could negatively affect muscle health in diabetes , via muscle cell death and resulting atrophy , this conclusion must await further work directly demonstrating the extent , if any , of the connection : the pathogenesis of diabetes is , after all , thought to be complex and multifactorial .
however , we have identified for the first time the skeletal muscle myocyte as a cell directly affected in this disease and the molecular players involved in this cellular pathology ( age / rage ) .
because , as we show here , elevated glucose also induces a repair defect in cell types other than the myocyte , it is possible that defective membrane repair may contribute to other diabetes complications as well .
Output:
| objectiveskeletal muscle myopathy is a common diabetes complication .
one possible cause of myopathy is myocyte failure to repair contraction - generated plasma membrane injuries . here
, we test the hypothesis that diabetes induces a repair defect in skeletal muscle myocytes.research design and methodsmyocytes in intact muscle from type 1 ( ins2akita+/ ) and type 2 ( db / db ) diabetic mice were injured with a laser and dye uptake imaged confocally to test repair efficiency .
membrane repair defects were also assessed in diabetic mice after downhill running , which induces myocyte plasma membrane disruption injuries in vivo .
a cell culture model was used to investigate the role of advanced glycation end products ( ages ) and the receptor for age ( rage ) in development of this repair defect.resultsdiabetic myocytes displayed significantly more dye influx after laser injury than controls , indicating a repair deficiency .
downhill running also resulted in a higher level of repair failure in diabetic mice .
this repair defect was mimicked in cultured cells by prolonged exposure to high glucose .
inhibition of the formation of age eliminated this glucose - induced repair defect .
however , a repair defect could be induced , in the absence of high glucose , by enhancing age binding to rage , or simply by increasing cell exposure to age.conclusionsbecause one consequence of repair failure is rapid cell death ( via necrosis ) , our demonstration that repair fails in diabetes suggests a new mechanism by which myopathy develops in diabetes . |
PubmedSumm6514 | ***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: parathyroid carcinoma is a very rare cause of primary hyperparathyroidism in children . in adults ,
the incidence is 1 to 5% , but in children , the incidence is not exactly known .
several articles have reported sporadic cases of parathyroid carcinoma occurring in pediatric patients [ 2 - 7 ] .
this patient is the eighth reported case of parathyroid carcinoma occurring in a child under the age of 16 years .
a previously healthy 13-year - old girl was admitted to our thyroid department for an asymptomatic palpable thyroid mass .
a 4 cm hard mass was palpable in the right lobe of the thyroid gland .
her total serum calcium was 12.0 mg / dl ( normal , 7.8 to 10 mg / dl ) , ionized calcium 1.52 mm / l ( normal , 0.96 to 1.4 mm / l ) , phosphorus 2.6 mg / dl ( normal , 2.9 to 4.3 mg / dl ) , alkaline phosphatase 2,700 iu / l ( normal , 25 to 100 iu / l ) , intact parathyroid hormone ( ipth ) level was 8,368 pg / ml ( normal , 15 to 65 pg / ml ) .
ultrasonography of the neck showed a 4 cm multifocal cystic mass in the right thyroid gland ( fig .
a 35 30 20 mm firm oval tumor was found behind and adherent to the right lobe of the thyroid gland .
an en bloc resection of the tumor , along the right lobe of the thyroid gland was performed and the central lymph node was removed .
the tumor weighed 22 g. on section it appeared grayish - yellow while histologically there were capsular , vascular and perineural invasion ( fig .
the patient underwent a chest computed tomography ( ct ) scan to evaluate for metastasis . on chest
ct scan , multiple scattered subpleural nodules in both lower lung lobes were found and we considered them to be benign nodules such as an inflammatory granuloma rather than metastases .
the total serum calcium and ipth levels decreased to 8.4 mg / dl and 49.48 pg / ml on the first postoperative day , and was 9.9 mg / dl , 70.99 pg / ml two weeks , respectively .
six months postoperatively , her calcium and parathyroid hormone levels increased to 9.7 mg / dl and 297.8 pg / ml , respectively . on chest
ct scan , 7 small well - defined nodules suspicious for hematogenous parathyroid carcinoma metastases appeared with increasing size bilaterally compared to her previous ct scan ( fig .
3 ) . bilateral lung wedge resection was performed by a thoracic surgeon and 8 metastatic nodules were removed .
six months later , her ct scan showed new multiple metastatic nodules in both lungs .
four years later , her calcium and parathyroid hormone levels increased to 12.4 mg / dl and 191.5 pg / ml .
bisphosphonates were used to control hypercalcemia , but improvement in bone mineral density was noted with no other symptoms present .
it usually occurs in middle - aged individuals during their third through sixth decades of life . until now
, only 6 cases have been reported of parathyroid carcinoma occurring within the age range of 8 to 15 years [ 2 - 7 ] .
the clinical manifestations of parathyroid carcinoma in pediatric patients include palpable neck mass , bone pain , weakness , pancreatitis , malaise , polyuria , polydipsia , nausea , and vomiting .
a common clinical manifestation among the reported patients was a palpable neck mass , as seen in our patient .
most patients reported had severe hypercalcemia , with total serum calcium levels greater than 13 mg / dl without metastasis .
although there were bilateral lung metastases , in our patient , the total calcium level only mildly increased , but markedly elevated levels of pth and alkaline phosphatase were seen .
a palpable neck mass with hypercalcemia and markedly elevated levels of pth in pediatric patients should raise concern for parathyroid carcinoma .
the histologic criteria for parathyroid carcinoma includes a trabecular pattern , mitotic figures , and capsular and blood vessel invasion .
since it is usually not diagnosed preoperatively , it is important that parathyroid carcinoma be considered intraoperatively when the tumor adheres to surrounding structures , including the thyroid gland , strap muscles , and the recurrent laryngeal nerve . if it is suspicious , aggressive treatment should be considered .
surgery is the most important treatment for parathyroid carcinoma . en bloc resection with ipsilateral thyroid lobectomy
, avoiding rupture of the tumor capsule and spillage of tumor cell , at the first operation is the only curative treatment , and aggressive initial treatment is important to reduce local recurrence and improve the prognosis .
considering that there have been several reports of metastasis and recurrence after operation , total calcium and ipth levels should be monitored frequently . in our patient ,
the lung nodule on chest ct scan was considered to be a benign nodule because of normalization of total calcium and ipth after operation . however , after 6 months , metastatic parathyroid carcinoma was suspected because of increased total calcium and ipth levels with increased nodule size on follow - up ct scan .
recurrence and systemic metastases occurs in up to 52% of patients with parathyroid carcinoma . like our patient 's case ,
the lung is the most frequent site of metastases while metastases to the bone , liver and brain can also occur . when metastases are found , metastasectomy is recommended to reduce hypercalcemia because severe hypercalcemia and its metabolic complications are associated with increased mortality . since the growth rate of parathyroid carcinoma is slow ,
chemotherapeutic agents , adjuvant radiotherapy and medical management , including calcitonin , mithramycin , and bisphosphonates , may be used for patients with uncontrollable hypercalcemia with unresectable or widespread metastatic disease . however ,
preoperatively , if there is severe hypercalcemia , elevated parathyroid hormone levels and palpable neck mass in a pediatric patient , parathyroid carcinoma should be suspected . en
hypercalcemia related metabolic complications are associated with increased mortality . even if metastasis or recurrence is detected
, aggressive resection of the metastatic parathyroid carcinoma is the most effective treatment to control hypercalcemia and improve survival .
Output:
| parathyroid carcinoma is a rare disease in pediatric patients . we present a case of a 13-year - old girl who presented to the thyroid department for an asymptomatic palpable neck mass for 1 year .
the high levels of calcium , ionized calcium , and parathyroid hormone level along with parathyroid scintigraphy studies suggested primary hyperparathyroidism .
parathyroid carcinoma was confirmed by biopsy and pathologic examination after resection .
six months postoperatively , persistent hypercalcemia and multiple lung metastases were found on computed tomography .
bilateral lung wedge resection was performed . en
bloc resection for primary parathyroid carcinoma and aggressive resection of metastatic disease is the most effective treatment to control hypercalcemia . |
PubmedSumm6515 | ***TASK***
the task is to summarize an input biomedical literature in six sentences
***INPUT***
the input is a biomedical literature
***OUTPUT***
the output is the summary of an input biomedical literature in six sentences
***DOCUMENTATION***
***EXAMPLES***
Input: a 48-year - old man underwent right partial glossectomy with neck dissection for tongue cancer under general anesthesia .
past medical history showed that he had been diagnosed with diabetes mellitus ( dm ) for five years and that he is a 30 pack - year smoker . during the five hours of operation , his vital signs were kept stable and blood sugar levels were well controlled between 82 - 84 mg / dl .
pulse oxygen saturation ( spo2 ) , pulse rate , and non - invasive blood pressure ( nibp ) were stable during immediate postoperative period in the recovery room .
he began complaining of troubled breathing and showed agitation 30 minutes after arrival in the recovery room .
we informed his otolaryngologist of the situation and relieved the dressing bandage around his neck . as his oxygen saturation gradually decreased to 0% , we started bag - mask ventilation .
although severe hypoxemia occurred , it did not lead to cardiac arrest , which was known from palpable pulse of radial artery throughout the course .
his heart rate remained above 40 beats / min . at the same time , his otolaryngologist arrived and immediately opened the incision site for decompression .
all vital signs were unremarkable ( spo2 98 - 99% , heart rate 80 - 120 beats / min , and temperature 36.0 - 36.2 ) , except blood pressure . it was checked below 90/60 mmhg twice during the 2 hours of operation , and ephedrine 10 mg was injected . on average , the mean arterial pressure was kept between 60 - 80 mmhg . at the end of the operation ,
bispectral index ( bis ) was increased to 90 and his eyes were opened spontaneously ; he was extubated .
however , soon after extubation , he showed generalized tonic - clonic seizure and it was only discontinued by inhalation of sevoflurane and administration of thiopental .
he was reintubated and phenytoin , lorazepam , and midazolam were administered to control the seizures .
he was admitted to the intensive care unit ( icu ) in a sedated state .
six hours later , when a tactile stimulus was applied , he developed widespread myoclonic seizures on all four limbs , even under infusion of large dose of anticonvulsants .
two days later , he was still deeply sedated to control myoclonic seizures , but the frequency and duration of seizures were only mildly reduced .
his brain computed tomogram ( ct ) showed no remarkable evidence of hypoxic brain damage and his electroencephalogram ( eeg ) study showed normal findings . on day 10 of hospitalization , his sedatives were completely withdrawn and he became alert with a frowned face and myoclonus affecting both knees and ankles .
three weeks later , magnetic resonance ( mr ) brain imaging did not show any abnormalities ( fig .
myoclonic status epilepticus ( mse ) within the first 24 hours after cardiopulmonary resuscitation ( cpr ) is generally considered as an accurate predicting factor of deleterious outcome enough to discontinue the treatment .
it is limited to ' 24 hours ' because mse is categorized into acute and chronic types , which have completely different prognosis .
chronic mse is called lance - adams syndrome , mostly shown a few days after cpr . since las shows much favorable prognosis compared to that of acute mse , it is important to remember the different clinical features of las .
moreover , las can develop acutely , which can lead to misdiagnosis even more easily , as in our case .
in addition to the time course , las is distinguished from acute mse by several clinical features , such as awareness , intention myoclonus , and normal brain ct or eeg .
the pathophysiology of las is elusive , but the mechanism of hypoxic brain injury has been assumed to be an important role . it is based on the fact that patients in previous reports of las were the survivors of ' hypoxic ' cardiac arrest rather than ' circulatory ' cardiac arrest [ 3 - 5 ] .
patients with pure hypoxic event seem to have far better outcome than those with circulatory cardiac arrest .
hypoxia produces hypercapnia , which results in increase of cerebral blood flow secondary to cerebrovascular dilation .
this results in the brain to be continuously supplied with nutrients and glucose and toxic metabolites to be removed by the circulation .
toxic metabolites , including lactic acid and free radicals damage not only astrocytes , but glial and mesenchymal cells as well .
time course in the present case showed acute mse that have easily led us to misdiagnosis .
it is important to differentiate between the two types of mse because therapeutic strategy must be established accordingly .
patients with las are aware , but it can be masked by deep sedation to control seizure .
eeg and brain ct can be delayed since mse is difficult to control even with high dose of anticonvulsants . moreover , as seen in our case , some patients with las can start myoclonic activity within 24 hours after cpr .
not misdiagnosing las , we should well acquaint ourselves with other predictors of poor outcome after cpr comprehensively ; absent pupillary light response or corneal reflexes at 72 hours , extensor or no motor response to pain at 72 hours , bilateral absent cortical responses on somatosensory evoked potentials at 72 hours , and serum neuron - specific enolase higher than 33 g / l . the present case might be regarded as a case of good outcome in spite of post - anoxic mse .
ironically , we did not expect any neurological complication at the time of the event in the recovery room , as anoxic time was around 3 minutes and cardiac arrest had not occurred .
have shown that the most important determinant of hypoxic injury was the duration of anoxia , which is defined as the interval between collapse and the beginning of cpr .
patients with favorable outcomes were anoxic for 4.1 minutes , compared to 8 minutes for patients with unfavorable outcomes .
only one report described the occurrence of las without cardiac arrest , which was assumed to be caused by fat embolism .
the survivor was a young healthy man involved in a traffic accident and his spo2 was decreased to 89% briefly without hypotension during orthopedic surgery .
it is worthy of notice what caused neurologic complications after brief hypoxemia without cardiac arrest .
we can presume that the following factors may have contributed to the development of las ; patient 's vulnerability , co - morbid conditions , surgical factor , and lack of post - hypoxic management .
the patient was a heavy smoker who had a history of dm and tongue cancer .
hyperglycemia is widely known as the main cause of endothelial dysfunction and neuronal cell death .
although his blood glucose had been well controlled , diabetic patients show more exaggerated cortical vasoreactivity and more regional cortical atrophy than non - diabetic patients .
long - lasting cigarette smoking is related to the increase in the level of inflammatory state and endothelial injury , which lead to impair vascular function and blood brain barrier integrity .
in addition , the hematoma in the neck may have compressed the jugular vein and/or the carotid artery compromising the cerebral blood flow as well , although circulatory arrest was not evident .
these factors could make our patient vulnerable to hypoxemia inhibiting cerebrovascular dilation and a maintenance of cerebral blood flow , which made similar processes to circulatory cardiac arrest .
thus , if patients who are predisposed to hypoxic injury were exposed to brief severe hypoxemia without cardiac arrest , they should be regarded as survivors of cardiac arrest and be provided with appropriate post - resuscitation managements . in this case
, blood pressure was not elevated enough to ensure adequate cerebral blood flow during 2 hours of surgical removal of hematoma after recovery from hypoxemia .
the mean arterial blood pressure is recommended to be maintained between 80 - 100 mmhg , at least for the first 24 hours after cardiac arrest .
blood glucose levels between 70 - 140 mg / dl are known to be associated with good neurologic outcome . since hyperthermia worsens neurologic outcome , fever must be avoided .
it is clear that acute onset mse does not always mean a poor neurologic outcome , but it does need more cautious approaches of diagnosis for several reasons .
short episodes of hypoxemia can occur at any time of anesthesia and bring detrimental neurologic consequences .
therefore , if those people with high risk of hypoxic injury have experienced hypoxemia , even for a short time , we should closely monitor them .
although it is not proven clearly , we may consider providing them an intensive post - resuscitation management to minimize unexpected complications .
Output:
| myoclonic status epilepticus ( mse ) within the first 24 hours after cardiopulmonary resuscitation ( cpr ) predicts poor prognosis , enough to discontinue the treatment .
in contrast , chronic mse appearing a few days after cpr is called lance - adams syndrome ( las ) , which is characterized by preserved intellect and a favorable prognosis .
we herein report a case of las , which developed after a transient hypoxic event without an overt cardiac arrest due to hematoma formation in the neck after partial glossectomy .
differential diagnosis was also challenging as las was developed 8 hours after the hypoxic event . |
PubmedSumm6516 | ***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: neurosyphilis has a special place in the history of neuropsychiatric diseases and the unraveling of the etiology , pathogenesis and control remains one of the instructive lessons in the principles and practice of medicine .
its propensity to affect all social classes is intricately linked to it being a sexually transmitted disease .
the ravages left in its wake as it spread across europe and the subsequent fascinating story of the discovery of penicillin leading to a treatment for syphilis gave impetus for its eradication in the second half of the nineteenth century . despite some measure of success in the control and eradication ,
neurological presentations still occur and can pose a diagnostic dilemma to physicians . as this illness has become rare , opportunities for modern day neuroimaging are few .
we report a case presenting as right sided limb weakness , facial numbness and slurred speech five months prior , diagnosed as a computed tomography ( ct ) scan negative vascular event in which there was subsequent deterioration leading to admission to hospital with features diagnostic of normal pressure hydrocephalus . additionally , clinical findings consistent with dementia paralytica were present and this combination together with ct and magnetic resonance imaging ( mri ) of the modern era are uncommon in the medical literature .
furthermore , to the best of our knowledge , there have been only seven reported cases of neurosyphilis presenting as normal pressure hydrocephalus .
a 46-year - old male presented the emergency department with a history of a decline in his mental status and reduced level of cognition for four months .
he sought medical care five months prior to his presentation for weakness of the right side involving right upper and lower limbs associated with facial numbness and slurred speech .
the ct brain at that time showed diffuse atrophic and small vessel changes with mild hydrocephalus ( figure 1a ) .
he was suspected to have an atherosclerotic cerebrovascular accident and was treated empirically with aspirin , simvastatin and atenolol .
as his condition was worsening he was brought to the emergency room , 5 months later .
he had a progressive decline in his level of cognition , speech and gait was unable to express himself to the extent where his answers became yes or no responses .
there was also significant weight loss of 20 pounds over the preceding three months without any change in appetite .
his prior medication included aspirin , atenolol , simvastatin , which was started since the presumed cerebrovascular event , associated with mild dyslipidemia and hypertension .
however , he had a 20-pack year history of smoking but stopped one year prior , and a history of alcohol use for 25 years .
there was no history of herbal , marijuana , cocaine or other illicit drug use .
there were no recent ill contacts or travel , and he never received blood transfusions or tattoos .
his relatives reported that he only had one sexual partner with whom he had three children and no history of prior sexual transmitted conditions .
he was anicteric , acyanotic , afebrile and his mucus membranes were pink and moist .
he had a glasgow coma scale of 12/15 accounted by the following responses : eye=4 , motor=6 , verbal=2 .
the blood pressure was 120/77 , pulse 65 , respiratory rate 20 , percutaneous oxygen saturation 99% , random blood glucose 147
he had a reduced power of 4/5 on the right upper and lower limb , with associated past pointing and intention tremor .
the patient was able to understand instructions but had severe difficulty executing them as well as expressing himself .
his reflexes were + + + in s1s2 , l3l4 , c5c6 and t1t2 on both right and left sides .
there were involuntary jerky myoclonic movements of both upper and lower limbs , which were worse with movement .
initial laboratory investigations showed normal renal function , liver function , thyroid function , c - reactive protein test , coagulation profile , electrolytes , serum b12 and red cell folate , hiv , hemoglobin electrophoresis , as well as a normal connective tissue screen .
the echocardiogram was normal with an ef 70% with no aortic regurgitation or aortitis / aneurysm .
electroencephalography showed subcortical dysfunction in left frontal lobe , accompanied by cortical irritability in the same area spreading posteriorly to central and temporal regions .
ct brain on admission showed dilated ventricles with an evans index of 0.523 out of proportion to the degree of cerebral atrophy and hypodensities in bifrontal lobes , which appeared to be consistent with edema and microangipathic small vessel disease ( figure 1b ) .
mri imaging on t1,t2,t2 flair , apparent diffusion coefficient ( adc ) and diffusion - weighted imaging ( dwi ) on admission confirmed hydrocephalus , bifrontal white matter hyperintensities , mesotempoaral atrophy and absence of infarctions or gumma ( figure 2a - e ) .
lumbar puncture on presentation and 3 months later showed elevated protein and serological evidence confirming neurosyphilis , with improvement at 3 months following treatment ( table 1 ) .
he was treated with aqueous crystalline penicillin g 4 million units intravenously every four hours , for 14 days .
prior to treatment he had a barthel scale 20 and modified rankin scale of 4 . at the end of 2 weeks of treatment
with improved verbal communication from the patient with treatment , he reported having multiple prior sexual partners , and did not use barrier contraception on all occasions . furthermore , he recalled having an ulcer on his penis several years prior however did not seek medical care .
the clinical manifestations of neurosyphilis can occur at any stage of the infection and include asymptomatic neurosyphilis , acute meningeal syphilis , meningovascular syphilis , paretic neurosyphilis , and tabetic neurosyphilis .
clinical features of the general paresis type are divided into early and late onset features , some of which can be seen in normal pressure hydrocephalus ( nph ) which presents with ataxia , urinary incontinence and dementia .
early symptoms of the paretic type syphilis include irritability , forgetfulness , personality changes , headaches , and changes in sleep habits .
late symptoms include emotional lability , impaired memory and judgment , disorientation , confusion , delusions , and occasionally seizures .
psychiatric manifestations range from depression , to delirium ( hallucinations ) , mania , and psychosis .
common neurological signs include pupillary abnormalities ( argyll robertson pupils occur in late paresis but are more often observed in tabes dorsalis , dysarthria , and tremors of facial , lingual , and hand muscles .
pathologically , there is atrophy of the frontal and temporal lobe with sparing of the motor , sensory , and occipital cortex .
the lissauer form of the disease , which occurs much less frequently , may also affect the cerebellum and basal ganglia .
the average time from infection to onset of paretic neurosyphilis is between 15 and 20 years .
most untreated patients die within 5 years after the onset of symptoms . to the best of our knowledge
since 1940 , limited case reports have encompassed the study of neurosyphilis in the post - penicillin era .
diagnosis requires clinical documentation of one or more of the characteristic symptoms of idiopathic nph in combination with a brain imaging study demonstrating non - obstructive ventricular enlargement disproportionate to cerebral atrophy .
our patient satisfied the clinical and radiological criteria for nph , which was further confirmed with normal cerebrospinal fluid ( csf ) opening pressures and positive serum and csf serology .
ct findings of patients with neurosyphilis are not well documented and a there are few reports on the mri findings of this disease . in one report
mri is the most sensitive technique in detecting changes in cerebral vasculitis involving large , medium , and small vessels .
most common mri diagnostic features in neurosyphilis are medium contrast enhancement , atrophy , white matter lesions , cerebral infarction , edema . in one study of patients with paretic neurosyphilis ,
the most common findings were generalized cerebral atrophy and foci of increased signal intensity on t2 weighted images .
there was a significant association between the presence of frontal lesions and overall degree of psychiatric morbidity .
those may be observed at any distribution , including subcortical white matter , deep white matter , or gray matter with areas of infarction and hemorrhage .
also , multiple areas of infarction in different vascular regions and of different ages are suggestive of cerebral vasculitis .
common findings include hypointensity on t1 , hyperintensity on t2 , medium contrast enhancement , perilesional edema , meningeal enhancement / dural tail , t1 isointense lesion , t2 isointense lesion , t2 hypointense lesion , cerebral infarction , arteritis , nonspecific white matter lesions involving the frontotemporal lobes , hippocampus and periventricular area , atrophy , gummas , extraaxial enhancement , high signal changes in the bilateral mesial temporal lobes including both hippocampus and amygdala in t2-images and flair and dwi sequence , ventricular dilatation . in neurosyphilis
the most frequently involved arteries are middle cerebral artery and branches of the basilar artery .
our patient had hypointensity on t1 in the left frontal region with hyperinternsity on the left frontal t2 mri with restricted diffusion on dwi image , which support a vasculitic expression of the disease .
the goal of therapy is to inhibit the progression of the infection and reverse the symptoms .
antibodies produced in response to the syphilis antigen results in neuroinflammation , which can contribute to initiation and maintenance of chronic inflammation and tissue damage in neurosyphilis independent of active infection .
data on the treatment of psychiatric symptoms associated with paretic neurosyphilis are very limited . for late disease , especially the parenchymatous forms ,
however with treatment there can be considerable regression of the neurological and psychological signs as in our patient .
repeat lumbar puncture at 3 months showed a fall in protein and vdrl titre correlating with clinical and radiological improvement .
a high index of clinical suspicion is required to diagnose neurosyphilis and commence treatment early . in a illustrative study of 116 patients with general paresis in china , after the initial evaluation
, neurosyphilis was not suspected in 36 percent of patients , which delayed the diagnosis for 1 to 24 months . despite the drastic reduction in the incidence of neurosyphilis with the advent of effective diagnosis and treatment
however , the primary and secondary ( p&s ) syphilis rates have increased almost every year since 20002001 . in 2014 ,
a total of 19,999 p&s syphilis cases were reported , and the national p&s syphilis rate increased to 6.3 cases per 100,000 population , the highest rate since 1994 . during 2013 - 2014 , according to the centers for disease control and prevention , the number of cases of late and late latent syphilis increased 7.9% ( from 21,819 to 23,541 cases ) .
therefore , syphilis remains a global health issue and clinicians are reminded to be vigilant since treatment of this reversible cause of dementia can be most rewarding .
Output:
| we report a case of a 46-year - old man presenting with a progressive cognitive decline , ataxic gait , urinary incontinence for 4 months and neuroimaging consistent with normal pressure hydrocephalus .
the atypical presentation of a progressively worsening dysphasia and a right hemiparesis dismissed as a vascular event 1 month earlier associated with normal pressure hydrocephalus prompted further investigations confirming neurosyphilis also manifesting as dementia paralytica .
treatment using consensus guidelines led to resumption of activities of daily living .
neurosyphilis , considered rare in the neuroimaging era , must still be considered a reversible cause of dementia and other neurological manifestations in contemporary neurological practice . |
PubmedSumm6517 | ***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: microfibrillated cellulose ( mfc ) , which was first developed in the early 1980s , is cellulose produced by high - shear mechanical homogenization ( often of enzymatically hydrolyzed cellulose pulp ) in water,(3 ) as opposed to microcrystalline cellulose ( mcc ) produced by hydrolysis with strong mineral acids to a level - off degree of polymerization ( dp ) .
due to the mild character of the enzymatic hydrolysis , the cellulose fibers in mfc are substantially longer than mcc whiskers,(4 ) and the fibers are therefore capable of producing very thick hydrogels at very low solid content ( > 99 wt % water content ) upon high - shear mechanical homogenization in the absence of protective hydrocolloids , such as carboxymethylcellulose.(5 ) by controlling the number of passes during high - shear homogenization , microfibrils with diameters in the range 10100 nm and lengths on the order of several micrometers can be obtained .
mfc(6 ) together with bacterial cellulose and green algae cellulose are examples of native nanocelluloses .
thanks to its special rheological properties , mfc hydrogels were originally envisaged for use as thickening agents in food and cosmetics products .
more recent applications include dried mfc - based materials such as paper of exceptionally high tensile strength,(12 ) optically transparent paper,(13 ) and flexible organic light - emitting diode ( oled ) displays.(14 ) highly porous nanocellulose materials are generally of high interest in the manufacturing of filtration media as well as for biomedical applications , e.g. , in dialysis membranes . upon removal of water , mfc , which is produced in the form of hydrogels with very high water contents ,
collapses into a dense opalescent cellulose material of high mechanical strength.(12 ) the collapse of the structure after removal of water is initially in the drying process due to the capillary forces which water exerts on the hydrophilic cellulose microfibrils and later in the drying process due to the strong cooperative hydrogen bonding between the hydroxyl groups on the nanocellulose surfaces .
thus , upon complete removal of liquid , the neighboring microfibrils are drawn into intimate proximity and bond through numerous hydrogen bonds.(15 ) if , however , the water in mfc hydrogels is replaced by a number of solvents with progressively decreasing polarity , the latter results in a gradual decrease of the capillary forces between the solvent and the hydrophilic cellulose fibrils.(16 ) removal of the nonpolar solvent in the last step by drying ( or vacuum treatment ) prevents the fibrils from collapsing which results in the formation of a highly porous cellulose material , often referred to as cellulose aerogels.(16 ) cellulose aerogels can also be obtained via lyophilization or supercritical co2 extraction . however ,
if the latter mfc aerogels are exposed to high relative humidity and hence allowed to reabsorb water , the structure will subsequently collapse upon drying . in recent years
it has been shown that polypyrrole ( ppy ) can be uniformly coated on cellulose fibers from commercial filter paper by a chemical polymerization - induced adsorption process.(19 ) more recently , it was demonstrated that composites of cellulose and ppy , in situ polymerized on the individual cellulose fibers ( which were extracted from the cladophora green algae ) , can be obtained using a similar approach.(20 ) the high surface area and good electronic conductivity of the latter material made it highly suitable for use in electrochemically controlled ion - exchange and ultrafast all polymer - based batteries.(24 ) it was demonstrated that the large surface area of the composite cellulose material ensured the attainment of a relatively high specific charge capacity , whereas the continuous , 50 nm thick ppy coating on the individual cellulose fibers enabled the ppy layers to undergo oxidation and reduction at high rates . since the latter results were obtained with cellulose from the cladophora sp .
algae while cellulose from land plants is typically used in contemporary industrial processes , it is very interesting to study if composites with similar properties likewise can be obtained with microfibrillated cellulose from wood .
it has been reported that mfc cellulose can be coated with polyaniline ( pani ) merely by dipping the mfc aerogel in a pani toluene solution.(17 ) a cellulose pani composite using in situ polymerization(25 ) and a conductive paper made from wood microfibers , carbon nanotubes , and poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate ) ( pedotpss ) using a layer - by - layer approach(26 ) have also been described . to obtain the high capacities required for efficient extractions of biologically interesting ions and
the fast charging and discharging needed in paper - based energy storage devices , the cellulose fibers in the conducting polymer composites must clearly serve the dual purpose of mechanically reinforcing the brittle conductive polymers and enhancing the specific charge capacity by providing a continuous 3-d scaffold of high porosity . in the present work ,
we describe a straightforward method of coating mfc microfibrils with ppy to obtain highly electroactive cellulose composites with large surface areas .
the described manufacturing process is entirely water - based and does not include any time - consuming solvent - exchange and drying steps to retain the large surface area of mfc upon water removal .
it is shown that the so obtained composites have surface areas of 90 m / g and conductivities of 1.5 s / cm which render them well - suited for use in applications involving large scale extraction of ions and novel energy storage devices .
the present paper is , to our knowledge , the first to report on a composite based on wood - derived mfc and ppy .
mfc was made from a never - dried bleached sulphite softwood cellulose pulp ( domsj eco bright ; domsj fabriker ab ) consisting of 40% pine ( pinus sylverstris ) and 60% spruce ( picea abies ) with a hemicellulose content of 13.8% and a lignin content of less than 1% .
this pulp was first refined in an escher - wyss refiner to 35 sr and was then treated with a small amount of an enzyme ( 10 ecu / g fiber of a monocomponent endoglucanase enzyme , novozym 476 , novozymes a / s , denmark ) at 60 c at ph 7.0 ( using a phosphate buffer ) for 2 h after ( the enzyme activity was also terminated by a 90 c heat treatment ) .
after the enzyme treatment , the pulp was again beaten to 90 sr in the escher - wyss refiner and finally brought to its na form , by an acid wash followed by adjusting the ph to 8.0 using naoh . finally , mfc was obtained by passing the fibers once through a microfluidizer ( type m-110eh , microfluidics corp .
mfc paper was obtained by diluting 240 mg of the thick 2 wt % mfc gel in 100 ml of distilled water after which the cellulose cake was collected on a filter paper in a buchner funnel employing reduced pressure and allowed to dry in air .
when dried , the mfc paper was carefully peeled off from the filter paper by moistening the backside of the latter .
the mfcppy composite , hereafter referred to as the composite material , was prepared by first dissolving 240 mg of the 2 wt % mfc hydrogel in 100 ml of distilled water .
this solution was then mixed with a solution of 3 ml of pyrrole ( purchased from vwr sweden and used as received ) in 100 ml of distilled water , the oxidizing solution , prepared by mixing 3 ml of pyrrole ( purchased from vwr sweden and used as received ) with a solution of 8 g of fecl3 in 100 ml of distilled water , and subsequently 160 l of 37% hcl was added to the resulting mixture .
the reaction between the oxidant solution and the mfc dispersion , giving rise to a layer of polypyrrole on the cellulose fibers , was allowed to proceed for 15 min .
the resulting structure was then collected on a filter paper in a buchner funnel employing reduced pressure and thoroughly washed with distilled water .
the filter paper was subsequently removed and the cellulose ppymfc cake was dried to constant mass on a petri dish in air .
ppy powder , used for the thermogravimetric analyses , was produced by mixing 3 ml of pyrrole with 8 g of fecl3 dissolved in 100 ml of distilled water .
the reaction was then allowed to proceed for 15 min after which the solid product was collected on a filter paper within a buchner funnel using reduced pressure and then thoroughly washed with distilled water .
thermogravimetric analyses ( tga ) of the composite ( 7.5 mg ) , the mfc paper ( 9.4 mg ) , and of ppy powder ( 7.1 mg ) was performed using a mettler toledo tga / sdta851 instrument .
all samples were placed in inert ceramic crucibles and were heated from 25 to 600 c at a heating rate of 10 c / min in the presence of a 20 ml / min flow of air .
the bulk resistances of the dried and as prepared composite samples were measured at room temperature using an agilent 34401a digital multimeter .
the sample conductivity , , was obtained from the measured resistance r according to = ( 1/r)(l / wd ) , where l is the length , w is the width , and d is the thickness of the sample .
silver paint was applied at the ends of the samples to ensure good electrical contacts with the clip probes .
cyclic voltammetric measurements on aqueous solutions were performed in a standard three - electrode setup utilizing an autolab / gpes interface ( eco chemie , the netherlands ) with the composite sample ( 15 mg ) as the working electrode , a pt wire as the counter electrode , and an ag / agcl electrode as the reference electrode .
the measurements , which were carried out in 2.0 m solutions of sodium chloride , were recorded in the potential interval between 1.0 and + 1.0 v employing a scan rate of 5 mv / s .
scanning electron microscopy ( sem ) images of the mfc paper as well as of the composite were taken with an environmental sem ( fei / philips xl 30 , the netherlands ) in the high vacuum mode ( 3.5 10 mbar ) .
prior to imaging , au / pt was sputtered on the samples to minimize charging effects .
nitrogen ( n2 ) and argon ( ar ) gas adsorption isotherms were recorded for the composite sample and the mfc paper , respectively , using an asap 2020 ( micromeritics , usa ) instrument .
both measurements were performed at liquid nitrogen temperatures ( i.e. , 77 k ) , and the specific surface areas of the samples were obtained from the isotherms using the bet method.(27 )
in figure 1 , photographs of the mfc paper and the composite sheets are shown .
the mfc paper was a 100 m thick , highly flexible translucent sheet possessing good mechanical properties .
the composite was in the form of a black sheet which had a thickness of roughly 1.5 mm .
it was mechanically stable but relatively brittle in comparison both to the mfc paper and to the corresponding previously described composites consisting of algal cellulose and ppy . to exemplify this ,
the algal cellulose composite sheets can be bent at an angle of 180 without breaking , while corresponding composites of mfc break if they are bent more than 5. the higher brittleness of the composite compared to that for the mfc paper could possibly be due to the fact that the interaction between the ppy coated fibers should involve ppyppy bonds , as these are intrinsically weaker than cellulose - to - cellulose bonds .
the relatively lower mechanical strength compared to that for the corresponding algae - based composite could be due to the shorter cellulose fiber length and the thinner individual cellulose fibers of the nanocellulose ( 17 nm ) as opposed to the 30 nm thick fibers of the algal cellulose.(10 ) thus , a proper fiber design with tailored dimensions of the fiber thickness and length could most likely make the composite less brittle .
also , the mfc hydrogel is sensitive to low ph and since the iron(iii ) chloride water solution added to initiate the polymerization has a ph of 2 , this will cause the hydrogel to partly collapse and also damage the fibers . both of these effects are expected to negatively influence the mechanical stability of the composite .
thus , polymerizing in a more neutral solution would most likely also help creating a less brittle composite .
figure 2 shows the tga results of the mfc paper and the composite material compared to that for the ppy powder used as a reference .
it is seen that water is continuously evaporating up to a temperature of about 100 c and that this results in a weight loss of 5 wt % for all samples .
polypyrrole is known to degrade in a three - step process , where water leaves the sample first and thereafter a degradation process involving the counterions follows .
finally , the polymer backbone is degraded . in the first derivative curve ( dtga ) of the polypyrrole weight loss ,
the temperature ranges for the loss of the dopant ion ( 105315 c ) and for the polymer backbone degradation ( 315600 c ) are in agreement with literature values.(29 ) the result of these processes is a steady degradation of polypyrrole until 37 wt % remains at 600 c .
the mfc paper underwent rapid decomposition in the interval between 250 and 350 c in a process typical for cellulose pyrolysis involving the formation of various anhydro - monosaccharides ( including levoglucosenone , levoglucosan , and 1,6-anhydro--d - glucopyranose ) , carbon oxides , and char.(30 ) this process is also clearly seen in the dtga curve for the mfc paper which has a monomodal shape with one maximum degradation temperature at 310 c . at 350 c ,
about 61 wt % of the mfc paper was decomposed and a total weight loss of 75 wt % was reached at 600 c . in the region between 230 and 360 c ,
the composite lost 19 wt % , mainly as a result of the degradation process of the cellulose part in the composite material but also partly caused by the thermal degradation of the polymer backbone in polypyrrole .
the process during which the counterion is expelled occurs before the polymer backbone degradation in ppy and is probably responsible for shifting the main composite degradation step to have its maximum degradation temperature at a lower temperature ( 280 c ) than the maximum degradation temperature of the mfc degradation process ( 310 c ) .
it is also seen in the dtga data that the composite follows the first process of the ppy before the main cellulose degradation and after which it follows the second degradation process of polypyrrole again .
this confirms the presence of both mfc and ppy in the composite material . at temperatures above 360 c
, the composite tga curve followed that of the ppy sample with a small shift in weight percentage corresponding to the residual amount of cellulose degradation products still present in the composite material .
this indicates that the majority of the composite is ppy . by considering the extent of decomposition of cellulose and ppy at 400 c and comparing this to the residual weight of the composite at the same temperature
thermogravimetric analysis showing the weight loss vs temperature for the mfcppy composite ( solid line ) , the mfc paper material ( dashed line ) , and ppy ( dotted line ) . in the inset , the derivatives of these curves are shown as a function of temperature .
conductivity measurements on composite sheets indicated an average electrical conductivity of 1.5 s / cm , which is somewhat higher than that for the algal - cellulose - based composites.(21 ) this indicates that the ratio of conducting ( ppy ) to nonconducting ( cellulose ) material was higher in the wood - based mfc composite , a hypothesis that is in good agreement with the tga results ( cf . above and ref ( 24 ) ) .
the electrical conductivity of the mfc paper sheet was , incidentally , nearly 10 times lower than that for the composite . as is seen in figure 3 , depicting a cyclic voltammogram for the composite in 2.0 m nacl electrolyte , the composite material also showed a high degree of electroactivity .
the characteristic redox behavior of ppy(31 ) is clearly seen , with an oxidation peak at + 0.27 v and a reduction peak at 0.45 v vs ag / agcl .
the onset of an overoxidation peak can also be observed at 0.75 v. to estimate the ion - exchange capacity of the composite , the charge capacity was calculated by integrating the current vs time curve from the anodic scan in the voltammogram .
this resulted in a charge capacity of 289 c / g ( or 80 mah / g ) for the composite , which is of the same order of magnitude as that previously found for the algal - cellulose - based composite electrodes used in an ultrafast polymer battery.(24 ) this clearly shows that the present mfc - based composite material could be used as an alternative material to the composite based on cellulose from the cladophora sp .
the three first cycles of a cyclic voltammogram for a mfcppy composite recorded in a 2.0 m sodium chloride solution employing a scan rate of 5 mv / s .
the sem image shown in figure 4a implies a dense , nonporous structure of the mfc paper .
in contrast , the sem image for the composite material ( see figure 4b ) indicates the presence of an open , porous structure of intertwined fibers . at certain locations , excess nodular agglomerates
are observed for the composite material ; these features are typical results from in situ aqueous polymerization of ppy on a hydrophilic surface.(32 ) gas adsorption analyses confirmed the low - porosity structure of the mfc paper , since the specific surface area of the mfc paper was too low to be determined using n2 adsorption analyses .
ar adsorption was therefore also employed , since ar has similar dimensions as n2 but provides a 4-fold gain in measurement sensitivity due to its lower saturation pressure .
on the basis of ar bet adsorption analyses , a specific surface area of merely 1.5 m / g was obtained for the mfc paper .
the latter results suggest that the mfc nanofibers collapsed into a dense , compact structure upon drying of the mfc hydrogels , in accordance with the previous results.(16 ) the n2 bet adsorption analyses of the composite material , on the other hand , resulted in a specific surface area of 89 m / g which is somewhat higher than the values previously obtained for algal - based composites .
the present results thus indicate that direct chemical polymerization of pyrrole monomers on mfc nanofibers in the hydrogel gives rise to a composite , the structure of which ( unlike that of mfc paper itself ) does not collapse upon drying .
it can thus be concluded that the inherent large specific surface area of the composite material could be maintained without the use of any special drying method , such as solvent - exchange drying , supercritical co2 drying , or lyophilization . by covering the individual cellulose fibers with a continuous layer of ppy , the contact angle between water and the composite fibers increases which results in weaker capillary forces during drying and second the ppy blocks hydrogen bonding between the individual fibers during drying . by varying the ppy
content of the composite , it was also found that the degree of loss of surface area upon drying decreased with increasing ppy content in the composite .
the fact that the straightforward coating of the cellulose fibers with ppy helps maintain the porous , large - surface - area structure of the
mfc significantly simplifies large - scale manufacturing of highly porous , electroactive conductive paper composites for applications including ion - exchange separations , dialysis membranes , and electrode materials for paper - based energy storage devices .
sem micrograph of the mfc paper ( a ) and mfcppy composite ( b ) .
it has been shown that it is possible to manufacture an electronically conductive high - surface area composite material composed of microfibrillated cellulose ( mfc ) and polypyrrole by direct chemical polymerization of pyrrole on wood - derived nanofibers in hydrogels without the need for sophisticated and time - consuming drying techniques such as solvent - exchange drying or lyophilization .
although brittle , the air - dried composite sheets exhibited a conductivity of 1.5 s / cm and a specific surface area of 89 m / g .
since the material was found to be electroactive with an ion - exchange capacity for cl of 289 c / g ( i.e. , a specific charge of 80 mah / g ) , it is clear that the present material has similar capacities as the corresponding composites based on cellulose from the cladophora sp .
algae recently used in a novel type of rapid - charging paper - based batteries .
the present findings consequently give rise to new exciting possibilities regarding large - scale production of inexpensive paper - based materials for energy storage as well as electrochemically controlled extraction and separation of biologically interesting compounds .
work along these lines and on the improvement of the mechanical properties of the composite is currently in progress .
Output:
| it is demonstrated that it is possible to coat the individual fibers of wood - based nanocellulose with polypyrrole using in situ chemical polymerization to obtain an electrically conducting continuous high - surface - area composite .
the experimental results indicate that the high surface area of the water dispersed material , to a large extent , is maintained upon normal drying without the use of any solvent exchange .
thus , the employed chemical polymerization of polypyrrole on the microfibrillated cellulose ( mfc ) nanofibers in the hydrogel gives rise to a composite , the structure of which unlike that of uncoated mfc paper does not collapse upon drying .
the dry composite has a surface area of 90 m2/g and a conductivity of 1.5 s / cm , is electrochemically active , and exhibits an ion - exchange capacity for chloride ions of 289 c / g corresponding to a specific capacity of 80 mah / g .
the straightforwardness of the fabrication of the present nanocellulose composites should significantly facilitate industrial manufacturing of highly porous , electroactive conductive paper materials for applications including ion - exchange and paper - based energy storage devices . |
PubmedSumm6518 | ***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: giant cell tumor ( gct ) of bone usually occurs in the epiphyses of long bones like the distal femur , proximal tibia , distal radius and proximal humerus1 .
craniofacial bone involvement is rare but has been reported to occur in the mandible , temporal bone , maxilla , occipital and sphenoid23 .
the incidence of gct varies between regions and is highest amongst the asian population , especially the chinese and japanese where they account for nearly 15% of all primary bone tumors4 .
although generally thought to be benign tumors , gcts are known to be locally aggressive at times , with local recurrence occurring in about 25%-35% of patients3 .
this is a case of a 22-year - old female who was previously well till she experienced swelling and pain over her right temporal region for 18 months .
she had episodes of jaw locking and could hear clicking sounds when chewing or talking .
she sought medical help but was treated as temporomandibular disorder ( tmd ) and was given analgesics , physiotherapy and an occlusal splint . the pain reduced after the prescribed treatment and
the swelling was inconspicuous initially but increased in size and hence further investigations were carried out .
examination revealed a 22 cm swelling over the right temporal region which was firm and tender on palpation . upon opening her mouth ,
computed tomography ( ct ) scan showed an aggressive erosive tumor of the squamous temporal bone extending to the right temporomandibular joint ( tmj).(fig .
a magnetic resonance imaging ( mri ) of the brain and tmj was performed which showed an extra - axial mass at the right middle cranial fossa involving the right tmj , measuring 4.21.62.6 cm .
2 ) during surgery , we used a modified frontotemporal flap for access to the temporal bone and tmj . an intraoral right sulcular incision along the ascending ramus of the mandible was used for access to the coronoid process .
intraoperatively , the tumor was seen to invade the temporal bone , mandibular condyle , tmj and overlying temporalis muscle but did not invade the temporal dura .
the patient underwent right partial temporal craniectomy , removal of part of the mandibular condyle and zygomatic arch , excision of the coronoid process , and excision of the tmj.(fig .
histopathological examination of the tumor revealed fibrous connective tissue with a few foci of numerous multinucleated giant cells , histiocytes , neutrophils , lymphocytes and occasional foam cells .
gcts are usually benign but have been known to be locally aggressive and occasionally metastasize , especially to the lung789 . very rarely , gcts may turn into sarcoma4 .
the usual sites of occurrence are the epiphysis of long bones and less than 2% occur in the head and neck region where the usual sites are the sphenoid and temporal bones10 .
portions of the temporal bone form by endochondral ossification , which is the same way epiphyses of long bones are formed and thus it is possible that the temporal bone is more prone to develop gcts because of this11 .
patients usually present with progressive pain and swelling over the site . in the temporal region ,
hearing impairment and facial nerve paralysis can occur due to compression or local invasion from the tumor12 .
involvement of the tmj causes jaw locking , deviation of mandibular movement and clicking sounds .
we would like to highlight the danger of treating patients as tmd before a precise diagnosis is made .
a thorough history and examination should be done and a list of differential diagnoses should be considered , including tumors14 .
tmd may present with pain and swelling at the temporal area as in this case , but swelling in tmd is different and not common .
some patients may still have temporal swelling but the swelling should be softer on palpation and not persistent in size as compared to tumors .
the swelling seen in tmd may be present during and after chewing and should decrease gradually between meals .
gcts appear lytic , subarticular , eccentrically located and usually lack a sclerotic rim on radiographs .
ct will rarely provide information that helps physicians arrive at a diagnosis but may be useful in delineating tumor extent , evaluation of cortical integrity and determination of tumor recurrence15 . on mri ,
gcts have low signal intensity on t1-weighted images , heterogeneous high signal intensity on t2-weighted images and heterogeneous enhancement with gadolinium .
mri is the preferred imaging modality for gcts , as the diagnostic accuracy of mri is high and it can detect soft tissue and intra - articular extension16 .
macroscopically , most gcts are soft and fleshy and appear grey to light red or dark reddish - brown . there may be areas of cyst , hemorrhage or fibrous septa formation as well .
the margins are usually ill defined , which explains the high percentage of recurrence if only curettage is done417 .
gct is a neoplasm of stromal - like neoplastic cells that are able to recruit macrophage and multinucleate osteoclast - like giant cells .
histologically , gcts are characterized by the finding of large osteoclast - like multinucleated giant cells scattered among a background of plump or spindle shaped mononuclear stromal cells .
the stromal cells may be mitotically active but should not have abnormal or atypical mitotic cells .
these giant cells have approximately 10 - 20 nuclei per cell , but may have 100 or more nuclei
. there may be reactive bone formation usually at the periphery and reactive changes such as reactive fibrosis , necrosis , hemorrhage and xanthogranulomatous inflammation .
this is likely the reason the ultrasound - guided fine needle aspiration biopsy result showed a xanthogranuloma .
gcts often have abundance of neovascularization , which explains the hemorrhages that are frequently seen within such tumors418 .
it is important to consider lesions such as giant cell reparative granuloma , hyperparathyroidism , non - ossifying fibroma , chondroblastoma , solid areas of aneurysmal bone cyst , malignant fibrous histiocytoma and osteogenic sarcoma4 .
surgery with the aim of wide excision is the mainstay of treatment for gcts , preferably with a wide margin of normal tissue81619 .
radiotherapy is reserved for cases where wide excision can not be achieved or for patients who are not fit for surgery .
irradiation - induced sarcomatous transformation is a known risk with orthovoltage radiation , but interestingly there is less risk with current use of megavoltage radiation19 .
denosumab , a receptor activator of nuclear factor kappa - b ligand ( rankl ) inhibitor has been approved for use in recurrent and unresectable gcts20 .
high dose dexamethasone therapy had been used effectively to rapidly reduce the size of these tumors but unfortunately , discontinuation of steroids is associated with re - growth in nearly every case4 .
Output:
| giant cell tumor ( gct ) of the craniofacial bones has been reported but they are not common .
this tumor occurs more often in women than in men and predominantly affects patients around the third to fifth decade of life .
gcts are generally benign but can be locally aggressive as well .
we report a case of gct involving the temporomandibular joint ( tmj ) , which was initially thought to be temporomandibular disorder ( tmd ) . a 22-year - old female presented with swelling and pain over the right temporal region for 18 months associated with jaw locking and clicking sounds . on examination ,
her jaw deviated to the right during opening and there was a 22 cm swelling over the right temporal region . despite routine treatment for tmd , the swelling increased in size .
computed tomography and magnetic resonance imaging of the brain and tmj revealed an erosive tumor of the temporal bone involving the tmj which was displacing the temporal lobe .
surgical excision was done and the tumor removed completely .
histopathological examination was consistent with a gct .
no clinical or radiological recurrence was detected 10 months post - surgery . |
PubmedSumm6519 | ***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 clinical evaluation of left ventricular ( lv ) diastolic function has been a difficult challenge .
lv filling and pulmonary venous doppler patterns have been utilized to estimate lv diastolic function , comprising variables as such stiffness , relaxation and even lv filling pressures .
doppler echocardiography has been utilized not only as a diagnostic tool but also as a monitoring tool , permitting follow - up of the effects of therapeutic interventions . in the previous issue of critical care , vignon and
colleagues demonstrated the value of tissue doppler imaging ( tdi ) to estimate lv diastolic function in a setting where acute alterations of preloading conditions may interfere .
they also clearly show some weak points with respect to the correct use of these function variables .
a typical transmitral doppler pattern consists of a larger early filling velocity wave ( e wave ) followed by an atrial contraction flow velocity wave .
reduced lv relaxation ( present in patients with advanced age , ischaemic heart disease or arterial hypertension ) will induce a reduction of the e wave in comparison with the atrial contraction flow velocity wave . increasing filling
pressures will increase the e wave velocity and will shorten the deceleration time of the e wave , with a transition from pseudonormalization to a restrictive pattern .
the phase of diastolic dysfunction for an individual patient remains difficult because of the interplay between relaxation and preload , which makes the routine pulsed wave doppler indices useless particularly in a setting where preloading conditions may change constantly and abruptly , as in many critically ill patients .
this doppler mode facilitates the assessment of the movement of the myocardial tissue , which typically reflects low velocity with very high amplitude doppler signals .
tdi can therefore be utilized to estimate myocardial velocities at the mitral annulus to obtain an impression of both systolic and diastolic myocardial motion .
the spectral doppler pattern is characterized by a systolic wave , an early diastolic wave ( e ' wave ) and an atrial velocity wave .
the technique is hampered by shortcomings related to the doppler technology ( angle misalignment , translation and rotation of the myocardial tissue ) and by intrinsic characteristics of myocardial function ( for example , the presence of regional wall motion abnormalities ) .
nevertheless , regional lv systolic function and lv diastolic function assessment is possible provided the sample volume is placed at the level of the mitral annulus and no ischaemia / infarction in the annulus region is present .
whereas the systolic component of this doppler pattern has been shown to be clearly preload dependent , less transparency exists on the load dependency of the diastolic myocardial velocities . with the initial description of this variable
, the index appeared to be load independent in settings of rapid infusion or preload alteration .
jacques and colleagues , however , reported both afterload independency and preload dependency of the e ' wave in situations where a normal lv function was present .
in contrast to the present study of vignon and colleagues , jacques and colleagues did not report the sample volume location .
comparison between the septal and lateral mitral annulus signals suggests that the septal signals are apparently more sensitive to preload alterations .
the reader , however , should bear in mind that the stability of the signals obtained at the septal side can be questioned , particularly in mechanically ventilated patients with ventilation - induced , right - sided , afterload shifts .
nevertheless , several authors have already reported differences in e ' wave velocities between the septal and lateral walls , without the ability to indicate a clear cause for this difference .
vignon and colleagues show no changes of the e ' wave in a rather small subset of intensive care unit patients , and again several issues have to be kept in mind .
the effects of drugs such as epinephrine , however , have not been described ; one should expect an increase of the e ' wave , at least when considering a similar effect to that with dobutamine .
it can thus be questioned whether an ultrafiltration ( and thus load diminishing ) effect is not concurring , keeping the e ' wave constant .
second , the influence of ultrafiltration itself on lv systolic function and lv diastolic function during septic shock is largely unknown .
the combination of lower preload ( by ultrafiltration ) and decreased lv function would render a less preload - dependent e ' wave , as suggested by jacques and colleagues the number of intensive care unit patients included in this subset is again far too small to conclude in a proper manner . from all these studies , it is unclear whether the discussed concepts apply to all haemodynamic states . the fact that the e wave / e ' wave relates to pulmonary capillary wedge pressure suggests that increased intrathoracic pressures could impede this relationship strongly .
apart from the fact that the e ' wave ( in conjunction with traditional doppler parameters ) is useful in determining lv diastolic function more accurately , tdi in the critically ill patient keeps more questions open than are answered .
e wave = early filling velocity wave ; e ' = early diastolic wave ; lv = left ventricular ; tdi = tissue doppler imaging .
this work was supported by an unrestricted grant from the international research centre of ghent university .
Output:
| assessment of left ventricular diastolic function in the critically ill patient remains a difficult issue in clinical practice . combined use of routine transmitral and pulmonary venous doppler patterns in conjunction with tissue doppler imaging
have been claimed to allow bedside diagnosis of diastolic dysfunction .
although in the previous issue of critical care it was clearly demonstrated there might be a difference in load dependency of the early myocardial tissue doppler velocity between lateral and septal placed sample volume , there remain still several unanswered questions , particularly with respect to the preload dependency of these indices . |
PubmedSumm6520 | ***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: recognition of abnormal glycosylation in almost any cancer type has raised great interest in the exploration of the tumor glycome for biomarker discovery [ 13 ] . in this study , we explored potential glycan markers that are overexpressed on the surfaces of breast cancers . a key immunological probe of this investigation is an antitumor monoclonal antibody ( mab ) , hae3 .
this mab was raised against epiglycanin , the major sialomucin glycoprotein ( ~500 kda ) of murine mammary adenocarcinoma ta3 cells .
it was initially called ae3 but was later renamed hae3 to avoid confusion with a commonly used anti - cytokeratin antibody in cancer research [ 6 , 7 ] .
interestingly , hae3 was found to strongly cross - react with a number of human epithelial tumors in tissues , including lung , prostate , bladder , esophagus , and ovarian cancers [ 5 , 810 ] .
this cross - species tumor binding profile suggests the possibility that hae3 may recognize a conserved tumor glycan marker that is coexpressed by both mouse- and human - derived epithelial cancers .
hae3 was initially suggested to resemble lectin peanut agglutinin ( pna ) , which recognizes the t disaccharide ( gal1,3galnac1- ) linked to ser / thr .
however , the antibody differed from pna in that the concentration of the blood group t disaccharide required for inhibition of binding to epiglycanin was 10 times greater than for pna .
moreover , a t - specific mab hh8 was found to be negative with epiglycanin in elisa microtiter plates .
reported recently that the neoglycolipid conjugates that display a single t disaccharide epitope were negative with hae3 .
given that hae3 has been analyzed using a large collection of synthetic neoglycoconjugates ( n = 492 ) , this study focused on identification of the potential natural ligands of hae3 .
in essence , we produced a comprehensive carbohydrate microarray using a large collection of purified natural carbohydrate antigens for screening .
these include a , b , o , lewis , i and i , and the blood group precursors of various biological origins .
as summarized below , we have revealed that hae3 is specific for a blood group precursor cryptic epitope that is normally hidden in the cores or internal chains of blood group substances but becomes differentially expressed in human breast cancer cells .
a preparation of human carcinoma - associated antigen ( hca ) ( 1 ) was kindly provided by dr .
the murine hybridoma igm antibody , hae3 , was produced by mouse immunization ( c57bl / j ) with asialoepiglycanin ( 85 ) [ 4 , 5 ] .
carbohydrate antigens applied in this study are listed in supplementary table 1 in supplementary material available online at http://dx.doi.org/10.1155/2015/510810 .
cancer cell lines used include breast - derived ( t-47d , sk - br-3 , mcf-7 , bt-549 , md - amb-231 , and md - amb-468 ) , lung - derived ( a549 ) , or prostate - derived ( pc3 ) epithelial tumor cell lines and a skin - derived melanoma skmel-28 .
microarray assays were performed as described . in brief , a microarray robot ( pixsys 5500c , cartesian technologies , irvine , ca ) was used to spot antigen preparations onto glass slides precoated with nitrocellulose polymer ( fast slides ; schleicher & schuell , keene , nh ) .
the printed microarrays were incubated at room temperature with hae3 ( igm ) antibody at 5 g / ml in 1% ( wt / vol ) bsa in pbs containing 0.05% ( wt / vol ) nan3 and 0.05% ( vol / vol ) tween-20 . an r - phycoerythrin- ( r - pe- ) conjugated affinity - purified f(ab ) fragment of goat anti - mouse igm secondary antibody preparation ( rockland immunochemicals , inc . , pa )
fluorescence intensity values for each array spot and its background were calculated using scanarray express software .
sas institute 's jmp - genomics software package ( http://www.jmp.com/ ; cary , nc ) was used for microarray data standardization and statistical analysis .
results of the microarray assay are shown as the means of fluorescent intensities ( mfis ) of triplicate detections of given antigen preparations ( figure 1(a ) and table 1 ) .
hae3 ( igm , 5.0 g / ml ) and an isotype control mab 9.14.7 ( igm , anti-(1,6)dextran , 5.0 ug / ml ) were applied to stain tumor cell lines .
the r - pe - conjugated goat anti - mouse igm antibody preparation described above was applied in the second staining step to reveal the antigen - captured igm .
facs data were collected with lsr - ii ( bd bioscience , san jose , ca ) and analyzed with flowjo ( treestar inc . ,
carbohydrate - specific elisa and elisa inhibition assays were performed as described [ 15 , 17 ] . in brief
, glycoprotein antigen preparations were diluted in 0.1 m sodium bicarbonate buffer solution , ph 9.6 , for coating on elisa microplates ( nunc , maxisorp , thermo scientific , rochester , ny ) followed by blocking using 1% bsa and 1x phosphate buffered saline tween-20 ( pbst ) .
mab hae3 ( igm ) ( 2.5 g / ml ) and biotinylated pna ( 2.0 g / ml ) were diluted in 1% bsa , pbst for the elisa binding assay .
the bound hae3 and pna were revealed by an alkaline phosphatase- ( ap- ) conjugated goat anti - mouse igm and an ap - streptavidin conjugate ( sigma chemical co. , st .
elisa inhibition assays were performed with epgn ( 85 ) ( 1 u / ml ) coated to display the native gp epitope and a series of blood group reference antigens as potential inhibitors ( 25.0 g / ml / each ) to compete with the hae3 ( 1.0 g / ml ) binding of epgn .
percent inhibition was calculated as follows : % inhibition = ( ( standard a blank a ) ( a with inhibitor a))/(standard a blank a ) . bio - gel p-10 filtration was performed following the manufacture 's manual ( bio - rad laboratories , hercules , ca ) with minor modifications . in brief , tij ii ( 20% from 2nd 10% ) substance was fractioned in a precalibrated bio - gel p-10 column .
the sizes of the tij ii substance were measured based on the neutral sugar elution profile with reference to the calibrated saccharide molecular weight standards as shown in figure 4 .
as shown in figure 1 and table 1 , an hca preparation ( i d 1 and 2 ) was spotted as a positive control for hae3 activity .
this hae3 glycoprotein preparation was affinity - purified from cultural supernatant of the lung cancer cell line a549 using an hae3-agarose column ( egenix , millbrook , ny ) . given that the simple o - glycan core t disaccharide ( gal1,3galnac- ) and its peptide conjugates were found to weakly but significantly inhibit hae3 binding to epiglycanin , we characterized a panel of blood group substances that carry o - glycan cores in this microarray screening .
a number of blood group precursors ( 2932 ) were plotted from 3 to 32 , which was followed by other antigens from 33 to 78 and microarray printing and scanning calibration controls in 79 and 80 .
blood group substance reference reagents used include the following : cyst9 and cyst14 , a active ; beach phenol insoluble , b active ; hog , h active ; js phenol insoluble , h and le active ; and n-1 20% from the second 10% , le active .
key blood group precursor references include og , tij ii , beach p1 , and mcdon p1 .
these precursor substances were prepared to remove most of the -l - fucosyl end groups that are essential for blood groups a , b , and h or lewis active side chains but possess the internal domains or core structures of blood group substances .
a large panel of other autoantigens and microbial polysaccharides were spotted in the same microarrays to examine potential polyreactivity of this igm antibody .
figures 1(a ) and 1(b ) illustrate a representative result of multiple microarray screening assays . in figure 1(a ) , the mfis of carbohydrate microarray detections of hae3 binding signal ( red column ) are plotted with corresponding local background reading ( blue column ) as an overlay plot .
each data point represents the mean of triplicate detections ; these are shown in the figure 1(b ) microarray image with the number of positive antigens labeled .
as illustrated , hae3 is strongly positive with hca ( 1 and 2 ) as expected .
importantly , this antibody selectively binds to four blood group precursor antigens , beach p1 ( 29 ) , mcdon p1 ( 30 ) , tij ii ( 31 ) , and og ( 32 ) .
by contrast , hae3 has no detectable cross - reactivity with blood group substances a , b. o , or lewis antigens , or the large panel of other carbohydrate antigens spotted in the same array .
figure 1(c ) is a schematic of blood group substance structure with the common blood group precursor core structure highlighted .
the four - branched structure in the circle represents the internal portion of the carbohydrate moiety of blood group substances , which was proposed based on extensive immunochemical characterization of precursor og and other p1 fractions of blood group precursors that were isolated from ovarian cancer cyst fluids [ 1922 ] .
selective detection of these blood group precursors from a large panel of blood group substances by hae3 illustrated that this antibody is specific for a shared cryptic glycoepitope of these precursor substances .
we further examined whether the observed hae3 binding reactivity can be attributed to cross - reactivity with t / tn glycoepitopes that are often expressed as components of blood group precursor substances . for this purpose , we tested elisa binding of hae3 or t - specific lectin pna with blood group precursor tij ii ( 31 ) and two t / tn - positive glycoconjugates , asialo - psm ( t ) ( 81 ) and asialo - osm ( tn ) ( 82 ) .
unlike pna , which binds to both tij ii and asialo - psm ( t ) , hae3 specifically binds to tij ii without cross - reacting with asialo - psm ( t ) or asialo - osm ( tn ) ( figure 2(a ) ) .
thus , hae3 binding of tij ii is irrelevant to the native t / tn - glyco - epitopes expressed by these glycoconjugates .
elisa inhibition assays further demonstrated that blood group precursors tij ii ( 31 ) and og ( 32 ) , but not other blood group antigens , including a ( 3 ) , b ( 14 ) , h ( 22 ) , t ( 84 ) , or tn ( 83 ) , significantly inhibited hae3 binding to the immunogen asialoepiglycanin ( 85 ) ( figure 2(b ) ) .
we examined whether the hae3 glycoepitopes were expressed as cell surface tumor markers . in the first set of experiments
, we screened a panel of four tumor cell lines by cell surface staining in flow cytometry .
these include ( a ) a breast cancer line , t-47d , which was selected owing to the fact that breast cancer patients were found to produce substances in circulation that are highly effective in inhibiting hae3 binding of epiglycanin [ 12 , 23 ] , ( b ) a lung cancer line , a549 , which is known to produce an hae3-positive substance in cell culture , ( c ) a prostate cancer line , pc3 , which is found to express a blood group b - related f77 glycoepitope [ 24 , 25 ] , and ( d ) a melanoma cell line skmel-28 , which is derived from skin but not epithelial tissue . as shown in figure 3(a ) , melanoma skmel-28 and prostate cancer pc3 were negative for hae3 .
by contrast , the breast cancer cell line t-47d was strongly positive in hae3-cell surface staining . given these results , we extended the facs analysis to a panel of seven human breast cancer cell lines , including two erpr lines ( t-47d and mcf-7 ) , one er ( sk - br-3 ) , and four triple - negative cancers ( bt-549 , hs 578 t , mda - mb-231 , and mda - mb-468 ) .
figure 3(b ) shows that two erpr lines , t-47d and mcf-7 , and two triple - negative lines , bt-549 and mda - mb-468 , are gp strongly positive .
by contrast , the two remaining triple - negative cell lines , hs578 t and mda - mb-231 , were hae3 negative .
facs analyses ( figure 3 ) revealed that five of the seven breast cancer cell lines are hae3 positive .
these are t-47d , mcf-7 , sk - br-3 , bt-549 , and mda - mb-468 .
bt-549 cells are triple - negative / basal - b mammary carcinoma ; mda - mb-468 cells are known as triple - negative / basal - a mammary carcinoma .
the two remaining gp triple - negative cell lines , hs578 t and mda - mb-231 , were basal - b mammary carcinoma .
it is important to extend this investigation to a cohort of breast cancer patients to examine whether this marker was significantly associated with metastatic breast cancer and breast circulating tumor cells , especially in patients with triple - negative cancer cells that lack specific surface biomarkers .
our carbohydrate microarray analysis has identified blood group precursor substances as the natural ligands of antibody hae3 .
as shown in figure 1 , four well - characterized blood group precursor reference antigens , beach p1 ( 29 ) , mcdon p1 ( 30 ) , tij ii ( 31 ) , and og ( 32 ) , were hae3 positive .
og and tij ii antigens were prepared by pepsin digestion , ethanol precipitation , and solubilization in 90% phenol , followed by fractional ethanol precipitation from phenol . beach p1 and mcdon p1 were obtained as the nondialyzable o - cores from partially hydrolyzed blood group antigen , beach b and mcdon a1 , respectively .
thus , these blood group precursor substances were prepared to eliminate peripheral glycoepitopes , such as a , b , h , or lewis antigen - specific epitopes , but preserve their o - glycan core structures , leaving a number of cryptic o - core epitopes exposed for antibody recognition .
selective detection of these blood group precursors from a large panel of blood group substances by hae3 demonstrated that this antibody is specific for a shared cryptic glycoepitope of these precursor substances .
the native blood group precursor substances are often more complex in carbohydrate structures than the most known model o - cores .
as determined by bio - gel p-10 filtration , the sizes of the tij ii blood group precursor substance were distributed in a range of molecular weights from 7 kda to 15 kda , approximately ( figure 4 ) . since
this antigen contains only approximately 2% peptide sequences , its mass is apparently made up predominately of carbohydrates [ 26 , 30 , 31 ] .
figure 1(c ) is a postulated blood group precursor core structure , which was proposed based on extensive glycan structural analyses and immunochemical studies of blood group substances [ 1922 ] .
the four - branched structure in the circle represents the internal portion of the carbohydrate moiety of blood group substances .
however , it is not impossible to rationally design and produce hae3-positive compounds by stabilizing relatively simple o - cores via specific structural modifications .
for example , a recent microarray screening revealed an unpredicted binding of this antibody to a sulfated glycolipid sm1a , gal1 - 3galnac1 - 4(3-o - sulfate)gal1 - 4glccer , which can be viewed as an o - core derivative .
sm1a naturally occurs in small amounts in normal kidney , but such a carbohydrate sequence has not been described in tumor glycome .
tumor - associated overexpression of blood group - related autoantigens is not limited to breast cancer .
recently reported that the natural ligand of a prostate cancer - specific mab f77 is in fact blood group h , which is built on a 6-linked branch of a poly - n - acetyllactosamine backbone [ 24 , 25 ] .
overexpression of gp in prostate cancers may reflect increased blood group h expression together with upregulated expression of branching enzymes . as illustrated in figures 13
, hae3 differs from f77 in glycan binding specificities and tumor binding profiles . unlike f77 , which is blood group h - specific and stains prostate cancer cell line pc3
, hae3 has neither reactivity with blood group h nor the cell surface targets of pc3 .
both hae3 and f77 studies call our attention to epithelial tumor expression of blood group substance - related autoantigens .
it is noteworthy that blood group substance antigens may also serve as the natural ligands of c - type lectin dc - sign , one of the key glycan - binding receptors of the conserved innate immune system [ 3335 ] .
our preliminary data indicates that the hae3-positive tijii antigen is likely a dc - sign ligand ( data not shown ) .
potential of this class of tumor glycoantigens as costimulators of the immune cells in both innate and acquired immune systems for tumor vaccine development and targeted immunotherapy is yet to be explored .
Output:
| using carbohydrate microarrays , we explored potential natural ligands of antitumor monoclonal antibody hae3 .
this antibody was raised against a murine mammary tumor antigen but was found to cross - react with a number of human epithelial tumors in tissues .
our carbohydrate microarray analysis reveals that hae3 is specific for an o - glycan cryptic epitope that is normally hidden in the cores of blood group substances . using hae3 to screen tumor cell surface markers by flow cytometry
, we found that the hae3 glycoepitope , gphae3 , was highly expressed by a number of human breast cancer cell lines , including some triple - negative cancers that lack the estrogen , progesterone , and her2/neu receptors .
taken together , we demonstrate that hae3 recognizes a conserved cryptic glycoepitope of blood group precursors , which is nevertheless selectively expressed and surface - exposed in certain breast tumor cells . the potential of this class of o - glycan cryptic antigens in breast cancer subtyping and targeted immunotherapy warrants further investigation . |
PubmedSumm6521 | ***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:
| exposure of low - passage endothelial cells in culture to nonlethal amounts of asbestos , but not refractory ceramic fiber-1 , increases cell motility and gene expression .
these changes may be initiated by the fibers mimicking matrix proteins as ligands for receptors on the cell surface . in the present study , 1- to 3-hr exposures of endothelial cells to 5
mg / cm2 of chrysotile asbestos caused marked cell elongation and motility .
however , little morphological change was seen when chrysotile was added to cells pretreated with either mannosamine to prevent assembly of glycophosphatidylinositol ( gpi)-anchored receptors or with herbimycin a to inhibit tyrosine kinase activity .
affinity purification of gpi - anchored urokinase - type plasminogen activator receptor ( upar ) from chrysotile - exposed cells demonstrated that asbestos altered the profile of proteins and phosphoproteins complexed with this receptor .
tyrosine kinase activities in the complexes were also increased by asbestos .
immunoprecipitations with selective monoclonal antibodies demonstrated that both chrysotile and crocidolite asbestos increase kinase activities associated with p60 src or p120 focal adhesion kinase ( fak ) .
further , chrysotile also changed the profile of proteins and phosphoproteins associated with fak in intact cells .
these data suggest that asbestos initiates endothelial cell phenotypic change through interactions with upar - containing complexes and that this change is mediated through tyrosine kinase cascades.imagesfigure 1 .
afigure 1 .
bfigure 1 .
cfigure 1 .
dfigure 1 .
efigure 1 .
ffigure 1 .
gfigure 1 .
hfigure 2 .
afigure 2 .
bfigure 3 .
afigure 3 .
bfigure 3 .
cfigure 3 .
d |
PubmedSumm6522 | ***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: osteoarthritis ( oa ) is the most prevalent disease associated with significant morbidity ,
and it is one of the most common causes of functional limitation and dependency .
knee oa is
particularly disabling because of symptoms such as pain , stiffness , and muscle weakness1 , 2 .
it
causes difficulty in climbing stairs , rising from a seated position , and walking , eventually
leading to physical disability and decreased quality of life3 , 4 . in many previous studies ,
associations between the mechanical axis alignment of the lower
limb and oa severity were found5,6,7,8,9 .
malalignments of the knee
joint make individuals more susceptible to developments of knee oa7 , and valgus or varus alignment increase the risk of knee oa
occurrence6 , 10 .
varus alignment , in particular , resulted in the largest stresses
at the medial compartment of the knee5 .
the adduction moment at the knee during gait is the primary determinant of the
medial - to - lateral distribution11 .
measurement of the knee joint moments provides an indication of the actual knee joint loads
related with the progression of oa12 .
the
knee adduction moment is mainly determined by the ground reaction force and its lever arm .
the line of action of the ground reaction force is directed to the medial side and the
center of the knee during gait , and its lever arm is the perpendicular distance from this
force vector to the knee joint center .
the knee adduction moment tends to adduct the knee
into a varus position , which is significantly correlated with disease severity11 .
an altered kinematic pattern of the ankle joint can also influence lower extremity
function13,14,15,16,17,18 , and the foot progression angle is related to the knee adduction
moment during gait19,20,21,22 . during the late stance phase in the gait cycle , the ground
reaction force passes through the forefoot , and medial to lateral disturbances caused by
foot rotation influence knee kinetics23 .
thus , patients with knee oa tend to rotate their foot in order to reduce their adduction
moments24 .
most previous studies on foot position and knee adduction moment have focused on foot
progression19 , 22 .
only a few studies have examined the relationship between the foot
rotation angle and knee adduction moment .
therefore , the purpose of this study was to
investigate the relationships among the foot progression angle , foot rotation angle , lower
limb alignment , and knee adduction moments in patients with degenerative knee oa .
we included 48 female patients aged 65 years and older who were diagnosed by radiography
with degenerative knee oa ( kellgren - lawrence grades 2 and 3 ) .
we excluded patients who
received more than 7 points in a physical therapy evaluation , which included an assessment
of sensation , circulation , range of motion , muscle strength of the lower limbs , and problems
concerning the feet and balance25 .
additional exclusion criteria were as follows : cardiovascular disease , diabetes , peripheral
nervous disease , history of lower extremity surgery , difficulties with visual or auditory
function , and cognitive disorder ( korean mini - mental state examination score 24 ) .
the
purpose of the study was explained to the participants , and informed consent was obtained .
the study protocol was approved by the institutional review board of sahmyook university ,
seoul , republic of korea . to assess the lower extremity alignment and weight - bearing ratio , a static radiographic
measurement system ( shimadzu 500 ma and 35.56 91.44 cm cassette ; shimadzu seisakusho ,
ltd . , kyoto , japan ) was used . to minimize errors during knee angle assessment ,
the examiner conducted anterior - posterior radiography
while subjects stood with their knees straight and their big toe and heel aligned with a
marked line .
the foot progression angle , foot rotation angle , and knee adduction moments were measured
by using a three - dimensional motion analysis system ( orthostat 6.29 ; motion analysis , inc .
,
santa rosa , ca , usa ) composed of two force plates ( piezoelectric force plate , 600 900 mm ;
kistler corp . ,
winterthur , switzerland ) , six infrared cameras , and 25 mm reflective markers .
the reflective markers were attached to the right and left of the center of the sacrum ,
anterior superior iliac spine , middle point between the greater trochanter and lateral
femoral condyle , lateral femoral condyle , middle point between the femoral condyle and
lateral malleolus , lateral malleolus , calcaneus , and 2nd metatarsal bone . after a warm - up walk ,
the assessment was conducted five times , and the subjects were asked
to walk as usual and had a 2 min rest during the intervals between the assessments .
the foot progression angle and foot rotation angle were measured at the point of the first
peak knee adduction moment in the early stance phase and during the second peak knee
adduction moment in the late stance phase .
additionally , we measured lower limb alignment
and the first and second peak knee adduction moments .
descriptive statistics were used for general features . to determine
the relationships among foot position , lower limb alignment , and knee adduction moments in
the subjects , we used pearson s correlation coefficient .
the general characteristics and gait analysis results of the subjects are described in
table 1table 1.general characteristics of the subjects ( n=48)parametersvalueskellgren - lawrence radiographic criteria
( n)2nd grade(21)3rd grade(27)vas ( scores)6.5 1.6age ( years)70.5 4.7height ( cm)154.2 4.9weight ( kg)64.7 8.4foot length ( cm)22.8 0.9foot breadth ( cm)10.2 0.7cadence ( steps / min)121.8 9.1gait speed ( cm / s)118.9 10.5step length ( cm)117.5 11.7stride length ( cm)8.9 1.8values are means sd .
vas : visual analogue scale . the foot position , knee adduction moments , and lower limb alignment of the
subjects are summarized in table 2table 2.foot position , knee adduction moment , and lower limb alignment of the subjects
( n=48)parametersvaluesfoot progression angle ( )early stance phase8.95 5.81late stance phase10.25
1.07knee adduction moment ( nm / kg)1st peak value0.55 0.132nd peak value0.47 0.16weight - bearing ratio ( % ) 32.0 12.2tibiofemoral angle ( )3.60 2.22femoral valgus angle ( )medial5.19 1.49lateral4.16 1.90patellofemoral q angle ( )8.79 5.46patellotibial q angle ( )9.23 5.40values are means sd .
vas : visual analogue scale values are means sd in the early and late stance phases , the foot progression angle was significantly
correlated with the first and second peak values of the knee adduction moments ( p < 0.05 )
( table 3table 3.relationship between foot position and knee adduction moment ( n=48)foot positionknee adduction moment1st peak value2nd peak valuefoot progression angle ( )early stance phase0.30*0.45*late stance phase0.33*0.48*foot rotation angle ( )early stance phase0.080.31*late stance phase0.140.38*pearson s correlation coefficient . *
the weight - bearing ratio was significantly correlated with the first and
second peak knee adduction moments .
the tibiofemoral angle was significantly correlated with
the first and second peak knee adduction moments ( p < 0.05 ) ( table 4table 4.relationship between lower limb alignment and knee adduction moment
( n=48)lower limb alignmentknee adduction moment1st peak value2nd peak valueweight - bearing ratio ( % ) 0.58 * 0.62*tibiofemoral angle ( )0.57 * 0.59*femoral valgus angle ( )medial0.390.27lateral0.080.23patellofemoral q angle ( )0.060.22patellotibial q angle ( )0.010.30pearson s correlation coefficient .
the results of the present study indicated that as the foot progression angle and foot
lateral rotation angle increased , the knee adduction moment decreased .
in addition , the
weight - bearing ratio and tibiofemoral angle assessment with mechanical axis alignment were
correlated with the knee adduction moments .
we found that a higher foot progression angle
was correlated with a reduction in knee adduction moments .
a study by lin et al .
demonstrated a reduced peak knee adduction moment when out - toeing during normal walking22 .
additionally , a study by teichtahl et al .
showed that subjects who walked with their feet externally rotated reduced their knee
adduction moment during the late stance phase23 .
guo et al . suggested that walking with a toe - out strategy may be
beneficial for persons in the early stages of medial knee oa , because the toe - out foot
position can transfer ground reaction force to the outside of the foot , resulting in a
reduction in knee adduction moment20 .
our results showed that the foot rotation angle was higher in the second knee adduction
moment .
similarly , teichtahl et al . described that the foot rotation position was more
related to the late stance phase than the early stance phase because of the ground reaction
forces distributed to the forward , inside , and outside parts of the foot23 .
anatomical lower limb alignment assessment of the knee measured on standard knee
radiographs is widely used to investigate the relationship with the knee adduction
moment5 , 10 ,
26 and to detect the progression of
degenerative knee oa23 , 27,28,29,30 .
the anatomical
tibiofemoral angle of the knee obtained using a short cassette ( 35.56 43.18 cm ) is more
widely used because of its economical and practical benefits .
however , a limitation of this
measurement is its wide variation due to exclusion of the hip and ankle joints28 .
thus , we used a measurement method that
assessed the mechanical tibiofemoral angle and the weight - bearing ratio using the hip , knee ,
and ankle angles with full - limb radiographs using a long cassette ( 35.56 91.44 cm )
. the weight - bearing ratio is calculated by measuring the distance from the medial edge of
the proximal tibia to the point where the weight - bearing line intersects the proximal tibia
and then dividing the measurement by the entire width of the proximal tibia ; the percentage
is calculated by multiplying this ratio by 100% . by definition , a weight - bearing line of
< 50% indicates varus alignment of the lower extremity , and a line > 50% indicates
valgus alignment19 . in our results ,
the
weight - bearing ratio was significantly correlated with the first knee adduction moment and
the second knee adduction moment , meaning that as the knee adduction moment in the early and
late stance phase increased , the inside of the knee joint loading increased . in the present study ,
the tibiofemoral angle of the subjects was 3.60 2.22 , which was
greater than that of a normal person ( 1.22.2)30 , because the subjects had knee oa with varus alignment . regarding
the relationship between the tibiofemoral angle and the knee adduction moment , the first and
second knee adduction moments were significantly correlated with the valgus alignment
angle .
the femoral valgus angle was 5.19 at the time of measurement of the medial tibiofemoral
angle and was 4.16 at the time of measurement of the lateral tibiofemoral angle .
these
values were less than that of the normal group ( 6)31 , because the subjects with knee oa had varus alignment .
therefore ,
there was no relationship between the femoral valgus angle and the knee adduction moment in
our subjects .
the normal anatomical q angle is 15 330 , but in our subjects , the patellofemoral q angle was 8.7 , and the
patellotibial q angle was 9.2 , both of which were less than the normal range due to the
varus deformity of the knee joints .
additionally , there was no significant relationship
between the q angle and the knee adduction moment . in conclusion
, we found that as the foot progression angle and foot lateral rotation angle
increased , the knee adduction moment decreased .
the weight - bearing ratio and tibiofemoral
angle assessment with mechanical axis alignment were correlated with the knee adduction
moments . however
, the femoral valgus angle and anatomical q angle may not be relevant to the
knee adduction moment .
therefore , the mechanical tibiofemoral angle is more appropriate for
assessing patients with knee oa than anatomical lower limb assessment .
these findings may be
helpful for selecting therapeutic options for patients with degenerative knee oa .
Output:
| [ purpose ] the aim of this study was to determine the relationships among the foot
progression angle , foot rotation angle , lower limb alignment , and knee adduction moments
in patients with degenerative knee osteoarthritis ( oa ) . [ subjects ] forty - eight patients
diagnosed with degenerative knee oa ( kellgren - lawrence grades 2 and 3 ) were included .
[ methods ] to assess the lower extremity alignment and weight - bearing ratio , static
radiographic measurement was used .
foot progression angle , foot rotation angle , and knee
adduction moments were measured by using a three - dimensional motion analysis system .
[ results ] the results of this study were as follows : the foot progression angle in the
early and late stance phase was significantly correlated with the first and second peak
knee adduction moments ; the weight - bearing ratio was significantly correlated with the
first and second peak knee adduction moments ; and the tibiofemoral angle was significantly
correlated with the first and second peak knee adduction moments .
[ conclusion ] the results
of the present study indicated that as the foot progression angle and the foot lateral
rotation angle increased , the knee adduction moment decreased .
the weight - bearing ratio
and tibiofemoral angle assessment with mechanical axis alignment were correlated with the
knee adduction moments .
these parameters may be helpful for selecting therapeutic options
for patients with degenerative knee oa . |
PubmedSumm6523 | ***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 past 2 decades , two noninvasive imaging methods , optical coherence tomography ( oct ) and fundus autofluorescence ( faf ) photography , have become available in routine clinical practice .
these methods provide qualitative and quantitative information about retinal changes that are not only important for the management of patients with many retinal diseases but also for patients with intraocular tumors.13 oct and faf imaging , when used together and combined with fundus photography , fluorescein angiography / indocyanine green angiography ( fa / icg ) , and ultrasonography , have been shown to be useful for early tumor diagnosis , monitoring of tumor growth , and follow - up of the results of therapies.111 today , spectral domain ( sd)-oct can provide cross- sectional images of the individual retinal layers and sd - oct scans have been used for the detection and quantification of secondary retinal , retinal pigment epithelium ( rpe ) , and choroidal changes overlying ocular tumors , for example , subretinal fluid ( srf ) , which may have predictive value for ocular tumor growth and could be a clinical indicator for malignancy in eyes with indeterminate choroidal melanocytic lesions ( imls).1,6,1012 oct was found to be more sensitive than clinical examination or ultrasonography for the identification of srf.13 sd - oct findings have recently been reported to be helpful in the diagnosis , follow - up , and treatment of different choroidal tumors , such as nevi , melanomas , metastases , hemangiomas , and lymphomas.6,1418 secondary retinal and rpe changes associated with various intraocular tumors can also be documented by faf .
faf imaging is a noninvasive method that provides a topographical map of lipofuscin , which is the main fundus fluorophore.19 lipofuscin ( a mixture of proteins , lipids , and small chromophores ) is the end product of phagocytosed photoreceptor outer segments , mostly accumulating within the rpe cells .
it has been shown that excessive accumulation of lipofuscin may impair the function of rpe cells , which may cause atrophy or death of the cells and , secondarily , the death of the overlying photoreceptors.20,21 using faf , it is possible to assess the metabolic health and functionality of the rpe cells.20 today , faf can be measured using a confocal scanning laser ophthalmoscope .
the auto - fluorescence images produced by a confocal scanning laser ophthalmoscope and fundus camera are similar.2,3 several authors have used confocal scanning laser ophthalmoscope to examine faf images in patients with intraocular tumors,810,2225 while others have studied the autofluorescence using a fundus camera.9,2631 the documented growth of an iml has been used as a surrogate for malignancy or a risk factor for the malignancy of the lesion since 1994.3235 there is evidence that large tumors are associated with a poor prognosis and higher metastatic rates.3638 shields et al37 reported that each extra millimeter in melanoma thickness meant a 5% higher risk of metastasis .
recently , damato et al38 revealed that ocular treatment of choroidal melanoma may prevent tumor growth , dedifferentiation , and metastatic disease in younger patients with small and less malignant tumors .
the findings in these two reports illustrate the importance of early detection and treatment of malignant uveal melanomas to ensure a more favorable prognosis .
apart from clinical risk factors , such as large tumor size , documented tumor growth , the presence of chromosome 3 monosomy ( loss of heterozygosity ) , and somatic mutations in genes , gnaq or gna11 have also been found to be strongly associated with death due to metastases in patients with uveal melanoma.3942 a good clinical evaluation of intraocular tumors , especially , of iml should include examination with ultrasound , oct , faf , fa / icg and , if necessary , biopsy for histological , cytological , and genetic analysis to enhance the accuracy of early diagnosis and improve prognosis.35 in this study , we have evaluated the clinical , oct , and faf findings in 49 patients with intraocular tumors to determine if oct and faf could be helpful in the differential diagnosis and management of different choroidal tumors .
forty - nine patients with untreated , macular , midperipheral , and juxtapapillary intraocular tumors , who had been periodically examined or who were referred for examination due to the finding of a new intraocular tumor between 2014 and 2015 , were prospectively included in the study and follow - up between 5 and 23 months .
patients were excluded if they had a choroidal tumor that had been treated previously , had non - clear media that would reduce the quality of the oct scans and faf images , or had very peripheral choroidal tumors that could not be imaged using oct and faf .
a diagnostic decision was made by an experienced specialist in ocular oncology for each patient included in this study , on the basis of clinical manifestation , including a- and b - scan ultrasonography , biomicroscopy , fundus photography , and in some cases fa / icg characteristics .
the characteristics showed in oct and faf under study were not used to confirm the initial diagnosis . in one patient ,
the patients studied were divided into four groups : nevi , imls , melanomas , and other choroidal tumors , which were compared .
all patients included in the study underwent ophthalmic examination , including best - corrected visual acuity ( va ) , slit - lamp biomicroscopy , funduscopy , standardized b mode , and if possible a mode , ultrasonography , and color fundus photography .
in addition , all patients underwent oct and faf imaging of the surface of intraocular tumors and macula .
a- and b - scan ophthalmic ultrasonography was performed on all patients using a cinescan s ( quantel medical , clermont - ferrand , france ) .
oct was performed using the sd 3d oct-1000 , version 3.00 software ( topcon , tokyo , japan ) .
the 3d macular scan option was used for all scans in this study , centered on the tumor and the fovea , covering 66 mm , with a resolution of 512128 pixels .
faf was performed with a topcon trc-50dx retinal camera ( topcon , with an excitation bandpass filter of 535585 nm and a barrier bandpass filter of 605715 nm ) .
the patchy pattern was defined as the presence of distinct areas of increased faf between areas of normal autofluorescence .
the diffuse pattern was characterized by the presence of increased faf with indistinct borders over a larger part of the tumor in the absence of intervening areas of normal faf.8 abnormal autofluorescence was also defined as either increased or decreased faf in comparison with background faf , and classified as isoautofluorescence , hypoautofluorescence , or a combination of hypoauto and hyperautofluorescence ( mixed).23,27 the following patient characteristics and clinical examination findings at the time of oct and faf imaging were recorded and analyzed : sex ( male , female ) , age , affected eye ( right eye , left eye ) , initial snellen va , tumor location ( distance to the optic nerve and to the foveola [ mm ] ) and largest basal diameter ( mm ) measured using fundus photography , tumor thickness ( mm ) measured by b - scan ultrasonography , tumor color ( pigmented , partially pigmented , and nonpigmented ) , tumor configuration ( flat , dome - shaped ) , srf on oct ( yes / no ) , and faf findings ( patchy , diffuse , isoauto - fluorescence , hypoautofluorescence , or a combination of hypoauto and hyperautofluorescence [ mixed ] ) .
the study was approved by the ethics committee of lund university and all the participants gave their written consent to participate according to the principles outlined in the universal declaration of helsinki .
the data were analyzed using computer software spss version 22 ( ibm corporation , armonk , ny , usa ) .
va was measured using a snellen chart and then converted to the logarithm of the minimum angle of resolution ( logmar ) before statistical analysis . the mann
whitney u - test was used for continuous variables and fisher s exact test was used for categorical variables .
the data were analyzed using computer software spss version 22 ( ibm corporation , armonk , ny , usa ) .
va was measured using a snellen chart and then converted to the logarithm of the minimum angle of resolution ( logmar ) before statistical analysis . the mann
whitney u - test was used for continuous variables and fisher s exact test was used for categorical variables .
the study consisted of 49 patients with intraocular tumors ( 19 males and 30 females ) .
the mean age was 64 years ( median , 68 years ; range , 1893 years ) .
the intraocular tumors were in the right eye in 24 patients and in the left eye in 25 patients .
the mean va ( logmar ) was 0.26 ( median , 0.16 ; range , 0.02.0 ) .
the mean distance from the tumor margin to the optic nerve was 2.6 mm ( median , 2.1 mm ; range , 0.09.3 mm ) and the mean distance to the foveola was 1.7 mm ( median , 0.8 ; range , 0.07.5 mm ) .
the mean tumor thickness was 2.3 mm ( median , 2.4 mm ; range , 0.011 mm ) and the mean value of the larger basal diameter of the tumor was 6.4 mm ( median , 6.0 mm ; range , 1.614.5 mm ) .
of the 49 patients studied , 19 had choroidal nevi , ten had imls , ten had malignant choroidal melanomas , and ten had other choroidal tumors ( two choroidal metastases , three choroidal osteomas , and five choroidal hemangiomas ) ( table 1 ) .
the mean follow - up ( months ) for all tumors was 13.55.4 ; choroidal nevi , 14.84.7 ; imls , 16.94.8 ; choroidal melanomas , 10.45.5 ; and other choroidal tumors , 10.74.8 .
both patchy and diffuse faf patterns were found to be associated with decreased va in all studied tumor groups ( tables 1 and 2 ) .
nineteen of the patients had a diagnosis of choroidal nevus and had been managed by regular observation .
the characteristics , clinical , oct , and faf findings , are given in tables 1 and 3 .
fundus photographs , faf images , and oct scans of two patients with choroidal nevi are presented in figure 1 .
no significant difference was observed between patients with choroidal nevi and imls , melanomas , and other choroidal tumors regarding sex , age , affected eye , and distance from the tumor margin to the optic nerve and foveola ( table 1 ) .
patients with choroidal nevi had significantly better va ( logmar ) than those with imls and melanomas ( p=0.016 and p=0.040 , respectively ) ( table 1 ) .
significant differences were observed between choroidal nevus and imls , choroidal melanomas , and other choroidal tumors regarding tumor thickness , largest basal diameter , tumor color , configuration , and fluid on oct and faf findings ( tables 1 and 3 ) .
choroidal nevi were often pigmented ( 89% ) , had a flat configuration ( 79% ) , had no fluid on oct ( 89% ) , and often demonstrated isoautofluorescence ( 42% ) and hypoautofluorescence ( 37% ) on faf imaging ( table 3 ) .
ten of the patients had a diagnosis of iml and had been managed by regular observation .
the characteristics , clinical , oct , and faf findings , are given in tables 14 .
fundus photographs , faf images , and oct scans of two patients with iml are presented in figure 1 .
no significant difference was observed between patients with iml and patients with choroidal melanoma and other choroidal tumors regarding sex , age , affected eye , va ( logmar ) , distance from the tumor margin to the optic nerve and foveola , tumor thickness , largest basal diameter , and fluid on oct and faf findings ( tables 2 and 4 ) .
a significant difference was observed only between iml and other choroidal tumors regarding tumor color ( p=0.001 ) ( table 4 ) .
two of ten ( 20% ) patients with iml exhibited tumor growth on follow - up < 12 months .
color fundus photographs , faf images , and oct scans before and 11 months after presentation of one patient with iml who showed tumor growth and faf pattern changes from patchy to diffuse are shown in figure 1 .
the characteristics , clinical , oct , and faf findings , are given in tables 14 .
color fundus photographs , faf images , and oct scans of two patients with melanoma are presented in figure 2 .
no significant difference was observed between patients with choroidal melanoma and iml and other choroidal tumors regarding sex , age , affected eye , distance from the tumor margin to the optic nerve and foveola , tumor thickness , or largest basal diameter ( table 2 ) .
significant differences were observed between patients with choroidal melanoma and other choroidal tumors regarding tumor color and fluid on oct ( p=0.011 and p=0.020 , respectively ) ( table 4 ) .
one patient with a tumor thickness of 1.9 mm , which was nonpigmented , was diagnosed as having choroidal melanoma by transretinal biopsy ( figure 2 ) .
five of them had choroidal hemangiomas , three osteomas , and two metastases ( one breast cancer and one systemic lymphoma ) .
the characteristics , clinical , oct , and faf findings , are given in tables 14 .
color fundus photographs , faf images , and oct scans of four patients with other choroidal tumors are presented in figures 3 and 4 .
there was no significant difference between other choroidal tumors and iml and choroidal melanoma regarding sex , age , affected eye , va , distance from tumor margin to the optic nerve and foveola , tumor thickness , or largest basal diameter ( table 2 ) .
all other choroidal tumors were nonpigmented ; 70% of them had no fluid on oct images and 40% showed isoautofluorescence on faf images ( table 4 ) .
nineteen of the patients had a diagnosis of choroidal nevus and had been managed by regular observation .
the characteristics , clinical , oct , and faf findings , are given in tables 1 and 3 .
fundus photographs , faf images , and oct scans of two patients with choroidal nevi are presented in figure 1 .
no significant difference was observed between patients with choroidal nevi and imls , melanomas , and other choroidal tumors regarding sex , age , affected eye , and distance from the tumor margin to the optic nerve and foveola ( table 1 ) .
patients with choroidal nevi had significantly better va ( logmar ) than those with imls and melanomas ( p=0.016 and p=0.040 , respectively ) ( table 1 ) .
significant differences were observed between choroidal nevus and imls , choroidal melanomas , and other choroidal tumors regarding tumor thickness , largest basal diameter , tumor color , configuration , and fluid on oct and faf findings ( tables 1 and 3 ) .
choroidal nevi were often pigmented ( 89% ) , had a flat configuration ( 79% ) , had no fluid on oct ( 89% ) , and often demonstrated isoautofluorescence ( 42% ) and hypoautofluorescence ( 37% ) on faf imaging ( table 3 ) .
ten of the patients had a diagnosis of iml and had been managed by regular observation .
the characteristics , clinical , oct , and faf findings , are given in tables 14 .
fundus photographs , faf images , and oct scans of two patients with iml are presented in figure 1 .
no significant difference was observed between patients with iml and patients with choroidal melanoma and other choroidal tumors regarding sex , age , affected eye , va ( logmar ) , distance from the tumor margin to the optic nerve and foveola , tumor thickness , largest basal diameter , and fluid on oct and faf findings ( tables 2 and 4 ) .
a significant difference was observed only between iml and other choroidal tumors regarding tumor color ( p=0.001 ) ( table 4 ) .
two of ten ( 20% ) patients with iml exhibited tumor growth on follow - up < 12 months .
color fundus photographs , faf images , and oct scans before and 11 months after presentation of one patient with iml who showed tumor growth and faf pattern changes from patchy to diffuse are shown in figure 1 .
the characteristics , clinical , oct , and faf findings , are given in tables 14 .
color fundus photographs , faf images , and oct scans of two patients with melanoma are presented in figure 2 .
no significant difference was observed between patients with choroidal melanoma and iml and other choroidal tumors regarding sex , age , affected eye , distance from the tumor margin to the optic nerve and foveola , tumor thickness , or largest basal diameter ( table 2 ) .
significant differences were observed between patients with choroidal melanoma and other choroidal tumors regarding tumor color and fluid on oct ( p=0.011 and p=0.020 , respectively ) ( table 4 ) .
one patient with a tumor thickness of 1.9 mm , which was nonpigmented , was diagnosed as having choroidal melanoma by transretinal biopsy ( figure 2 ) .
five of them had choroidal hemangiomas , three osteomas , and two metastases ( one breast cancer and one systemic lymphoma ) .
the characteristics , clinical , oct , and faf findings , are given in tables 14 .
color fundus photographs , faf images , and oct scans of four patients with other choroidal tumors are presented in figures 3 and 4 .
there was no significant difference between other choroidal tumors and iml and choroidal melanoma regarding sex , age , affected eye , va , distance from tumor margin to the optic nerve and foveola , tumor thickness , or largest basal diameter ( table 2 ) .
all other choroidal tumors were nonpigmented ; 70% of them had no fluid on oct images and 40% showed isoautofluorescence on faf images ( table 4 ) .
the results of the present study demonstrate that the choroidal nevi located in the macular region , midperiphery , and juxtapapillary regions were pigmented in 89% , flat in 79% , and only 11% showed srf on oct .
these findings can be compared with those of several other studies on choroidal nevi using oct imaging in which it was reported that between 16% and 30% of the patients with choroidal nevi had srf on oct.7,13,14 the choroidal nevi included in the present study exhibited isoautofluorescence in 42% , hypoautofluorescence in 37% , a patchy faf pattern in 16% , and a diffuse pattern in 5% of the cases .
the faf abnormalities in the choroidal nevi identified in our study were somewhat different from faf findings reported by shields et al26 who found hypoautofluorescence in 56% and isoautofluorescence in only 18% of cases with choroidal nevi . the higher rate of isoautofluorescence in our study could be due to the fact that maybe we included less chronic choroidal nevi with less chronic rpe degenerative features compared to shields et al.26 we also found both patchy faf patterns and diffuse patterns in choroidal nevi , while gndz et al8 reported that all the choroidal nevi in their study showed a patchy faf pattern .
the present study demonstrates that apart from tumor features , such as tumor thickness , and the largest basal diameter , oct and faf findings were also very valuable in differentiating choroidal nevi from imls and choroidal melanomas .
the imls in this study exhibited significantly greater tumor thickness and larger basal diameter than the choroidal nevi , and did not show any significant differences between choroidal melanoma and other choroidal tumors regarding va , all tumor characteristics , or oct and faf findings .
singh et al10 studied 38 patients with iml or with a small tumor according to the size - based nomenclature used in the collaborative ocular melanoma study using sd - oct and faf imaging and found that nearly 60% of cases had srf on oct .
srf was detected in 70% of the cases of iml using oct in this study , which is very similar to the oct findings reported in the two studies mentioned above .
these faf findings are almost identical to the faf findings in patients with choroidal melanoma in the present study .
only a few authors have studied faf overlying iml and found no characteristic patterns of faf.8,10,23 our study demonstrates that tumor characteristics , oct , and faf findings , were not valuable in differentiating an iml from choroidal melanoma or other choroidal tumors , but were valuable in monitoring tumor growth .
two of ten patients ( 20% ) with iml in this study showed tumor growth on follow - up < 12 months .
the presence of documented growth of an iml has been used as a surrogate for malignancy for many years and is important in identifying imls that require treatment.4,3235 the two most important predictive clinical risk factors for tumor growth are the presence of srf overlying the tumor and orange pigment on the surface of the tumor .
the evaluation of these two risk factors is most useful using oct and faf imaging.4,10 the choroidal melanomas in this study were nonpigmented in 40% of the cases , and 90% of the cases had srf on oct .
muscat et al7 detected srf overlying the untreated choroidal melanomas in 100% of their cases using oct .
the faf patterns of choroidal melanomas were classified as either patchy or diffuse in this study .
this classification was used previously by gndz et al.8 they defined the patchy faf pattern over choroidal melanomas as the presence of distinct areas of increased faf between areas of normal autofluorescence , and the diffuse pattern of faf was characterized by the presence of increased faf with indistinct borders over a larger area of the tumor .
we found that 60% of the cases of choroidal melanoma had a patchy faf pattern , while gndz et al8 reported that 68% of choroidal melanoma cases had a diffuse faf pattern
. the higher rate of diffuse faf patterns reported by gndz et al8 compared to the present results could be due to the fact that they included larger choroidal melanomas in their study , and their observations that the diffuse faf pattern was significantly associated with increased tumor thickness and increased largest basal diameter .
shields et al27 also found that the hyperautofluorescence of choroidal melanomas increased with larger tumors , pigmented tumors , and those with disrupted overlying rpe
. only one of the ten ( 10% ) patients with choroidal melanoma in this study was diagnosed by transretinal biopsy .
this is often done without biopsy for histopathological , molecular , or cytological analysis , which prevents adequate prognosis based on histopathological and genetic analysis .
kivel and kujala43 reported that the most adequate criteria for prognosis of choroidal melanomas were analysis of chromosomal alternations and gene expression profiling .
the presence of only one copy of chromosome 3 ( complete monosomy 3 ) was observed in many choroidal melanomas that had metastasized and at 3-year follow - up , for tumors with complete monosomy 3 , the occurrence of metastasis was 0% for small , 24.4% for medium , and 57.5% for large melanomas.41,43 the recent findings by shields et al37 that each extra millimeter increase in melanoma thickness was associated with 5% increased risk of metastasis and damato et al38 that ocular treatment of choroidal melanoma may prevent tumor growth , dedifferentiation , and metastatic disease in younger patients with small and less malignant tumors indicate the importance of early and accurate diagnosis by sound clinical evaluation , including oct , faf imaging , and biopsy .
patients with other choroidal tumors in this study exhibited no significant difference regarding clinical and tumor characteristics compared with imls and choroidal melanoma cases . all were nonpigmented , and only 30% of the cases had srf on oct .
a low rate of the srf on oct ( in only 19% of the cases with choroidal hemangioma ) was also reported by ramasubramanian et al.31 we found srf on oct in 67% of the cases with osteoma ( all had choroidal neovascularization ) , while freton and finger16 found srf in only 27% of the cases with osteoma .
our patients with choroidal metastatic lesions exhibited srf in 50% of cases , whereas collet et al24 found srf in 73% of their cases . in two of our cases
( breast cancer metastasis and choroidal lymphoma metastasis ) , oct was valuable in monitoring the response to treatment ( figures 3 and 4 ) .
oct and faf imaging have been demonstrated to be important for monitoring the response to treatment of intraocular tumors by several authors.20 no characteristic patterns of faf were found in our patients with other choroidal tumors .
previous studies on faf imaging in intraocular tumors have revealed that choroidal nevi typically had overlying hypoautofluorescence due to the degeneration or atrophy of rpe cells , and choroidal melanomas , especially large melanomas , generally had confluent / diffuse overlying hyperfluorescence due to the accumulation of lipofuscin within the rpe cells and within srf.810,22,27,30 patients with choroidal metastases and choroidal hemangiomas in the present study showed both a patchy faf pattern and isoautofluorescence .
it has been reported that choroidal metastases and choroidal hemangiomas often exhibit overlying hyperautofluorescence that is correlated to focal lipofuscin accumulation in the overlying rpe cells as well as in srf , particularly in acute tumors.24,30,31 two patients with osteoma in this study had both hypo- and hyperautofluorescence ( mixed ) overlying the tumors .
characteristic faf patterns have recently been reported in patients with osteomas , with isoautofluorescence overlying calcified regions of the tumor due to the intact rpe , and general hypoautofluorescence in decalcified regions due to hyperplasia , metaplasia , and atrophy of the rpe.25,30 our study had several limitations , including the small patient number in each studied group , and the grading of patchy versus diffuse faf pattern of intraocular tumors was not done in a masked fashion but interobserver variability was tested in the classification of faf pattern .
all patients but one had the preliminary diagnosis based on clinical tumor features , funduscopy , ultrasound measurements , and fa / icg findings .
there is thus considerable evidence that oct and faf imaging should be incorporated into diagnostic algorithms for intraocular tumors in clinical care in order to improve the characterization of tumors , and promote early diagnosis and treatment to improve patient survival and decrease the risk of metastasis , especially in patients with iml.4,68,10,11,20,2231
this study demonstrates that both oct and faf were helpful in the differential diagnosis of choroidal nevi versus imls , choroidal melanomas , and other choroidal tumors .
the accurate and periodical clinical evaluation of patients with intraocular tumors using ultrasound in combination with oct and faf for the detection of both srf and characteristic faf patterns overlying the tumors may be useful for detection of tumor growth .
Output:
| purposeto describe clinical , optical coherence tomography ( oct ) and fundus autofluorescence ( faf ) findings in patients with intraocular tumors and determine if oct and faf could be helpful in the differential diagnosis and management of different choroidal tumors.methodsforty-nine patients with untreated , macular , midperipheral , and extrapapillary intraocular tumors were included .
all patients underwent ophthalmic examination : best - corrected visual acuity , slit - lamp biomicroscopy , funduscopy , and standardized b mode , and if possible a mode , ultrasonography , and oct and faf imaging of the surface of the intraocular tumors.resultsof the 49 patients studied , 19 had choroidal nevi , ten had indeterminate choroidal melanocytic lesions ( imls ) , ten had malignant melanomas , and ten had other choroidal tumors .
the choroidal nevi revealed subretinal fluid ( srf ) on oct in only 11% .
faf detected isoauto - fluorescence in 42% , hypoautofluorescence in 37% , patchy faf pattern in 16% , and a diffuse faf pattern in 5% .
seventy percent of patients with iml showed srf on oct and 20% showed tumor growth on follow - up , detected only by oct and faf imaging .
faf revealed a patchy pattern in 50% and a diffuse pattern in 40% of cases with iml .
ninety percent of the patients with choroidal melanoma had srf on oct and faf revealed a patchy pattern in 60% and a diffuse pattern in 40% .
patients with other choroidal tumors had srf on oct in 30% of cases and no characteristic pattern on faf.conclusionboth oct and faf were helpful in the differential diagnosis of choroidal nevi versus imls , choroidal melanomas , and other choroidal tumors .
also , detailed and periodical clinical evaluation of patients with intraocular tumors using oct and faf imaging for the detection of both srf and faf patterns overlying the tumor can be useful for detection of tumor growth . |
PubmedSumm6524 | ***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: cystic lesions of the pancreas occasionally present problems in diagnosis and management , especially when found incidentally .
cystic lesions can be broadly classified as follows : congenital true cyst ; primary cystic neoplasms ; acquired cysts , including parasitic cysts and postinflammatory cysts ( pseudocyst , retention cyst ) ; extra - pancreatic cystic disorders masquerading as pancreatic cyst ; and other miscellaneaus cystic lesion .
endometriosis is defined as the presence of endometrial glands and stroma occurring outside of the uterine cavity .
it has been encountered in multiple sites such as the ovaries , fallopian tubes , uterus , peritonium , uterine ligaments , rectovaginal septum , cervix , vagina , vulva , skin , umbilicus , incisional scars , hernia scars , bladder wall , kidney , pelvic lymph nodes , extremities , lung , pleura , large intestine , rectum , appendix , gallbladder , stomach , and spleen .
we report a patient with a cyst in the body of the pancreas that on pathologic examination proved to be lined by the ectopic endometrial tissue .
a 21-yr - old korean woman was admitted to the hospital with a recurrent epigastric pain and 8 kg weight loss over a one year period .
she denied a history of hepato - biliary disease , alcoholism , previous surgery , traumatic abdominal injury or cyclic abdominal pain .
her menstrual history was normal . on admission , her blood pressure was 120/80 mmhg , pulse 80/min , temperature 36.5c and respirations 20/min . on examination , there was no abnormally palpable mass in her abdomen .
laboratory data on admission was as follows : hemoglobin 12.4 g / dl , hematocrit 37.3% , white blood cell count 5,500/mm , platelet 300,000/mm , total protein 6.4 g / dl , albumin 4.2 g / dl , total bilirubin 0.7 mg / dl , ast 10
iu / l , alt 9 iu / l , alklaine phosphatase 135 iu / l , ggt 12 iu / l , amylase 60 u , cea 1.24 ng / dl , ca-125 8.71 u / ml , ca 19 - 9 54.34 u / ml , afp 0.4 ng / ml , ca 15 - 3 9.09 u / ml .
computed tomography of the abdomen showed a 3.54.0 cm - sized , oval - shaped low density cystic mass involving the body of the pancreas with bulging - out contour .
there was no definite pancreatic duct dilatation ( figure 1 ) . with a preoperative diagnosis of mucous cystic adenoma , the patient underwent partial pancreatectomy .
gross finding of surgical specimen revealed a 4.04.04.5 cm well - circumscribed cyst located within the pancreatic stroma .
the cyst was lined by a smooth , trabeculated , grey - brown wall with focal areas of hemorrhage .
on microscopy , the cyst was covered with fibrous tissue containing endometrial elongated glands consisting of cuboidal and columnar cells with basal nuclei and amphophilic cytoplasm .
the glands were admixed with well - vascularized spindle cell stroma containing multiple areas of focal hemorrhage and hemosiderin deposition in macrophage ( figure 2 ) .
immunohistochemical examinations showed positive tests to antibodies to the estrogen receptor - related protein ( er ) and the nuclear progesteron receptor protein ( pr ) ( figure 3 ) .
extrapelvic endometriosis refers to endometropic implants found in other areas of the body , including the vagina , vulva , cervix and perineum , in the inguinal canal , the urinary system , the gastrointestinal tracts , pulmonary structures , extremities , skin and central nervous system .
the epidemiology , diagnosis and natural history of extrapelvic endometriosis appear to differ somewhat from endometriosis .
it remains uncertain whether lesions distant from pelvic sites even represent the same disease process and whether the same diagnostic and treatment modalities are appropriate .
the intestines are involved in 515% of all the cases of endometriosis , and the gastrointestinal tract is the most common site of extrapelvic disease .
cystic endoteriosis of the pancreas is very rare and has been mentioned in the literature only four times .
but , in our presented case , an endometrial cyst was located in the body of the pancreas .
endometriosis is defined as the presence of endometrial glands and stroma occurring outside of the uterine cavity .
histopathological demonstration of endometrial tissue from various parts of the mass is desirable for confirmation of the diagnosis . in our presented case ,
immunohistochemical investigations of a previous report with antibodies to the estrogen receptor - related - protein and the nuclear progeteron receptor protein was negative . in our case however , immunostaining were positive .
the possible pathogenesis of endometriosis in multiple organs has been the subject of controversy and numerous theories . for more than 70 years
interest in the genesis of the endometric lesion has been a focus since the earliest studies .
the theory of direct extension proposes that endometriosis results from direct invasion of the ectopic endometrium through the uterine musculature .
spread of endometrial glands and stroma through muscle fibers or along lymphatic and venous channels may , in fact , be a progenitor of adenomyosis , but the relationship of direct endometrial spread to endometriotic implants is not well established .
the theory of coelomic metaplasia holds that endometriosis developed from metaplasia of cells lining the pelvic peritonium .
this is based on embryologic studies demonstrating that mullerian ducts , germinal epithelium of the ovary and pelvic peritoneum are all derived from the same embryologic precusor .
an attractive component of the coelomic metaplasia theory is that it can account for the occurrence of endometriosis anywhere in the abdominal cavity .
the theory of lymphatic and vascular metastasis had esuggested that endometriosis could result from lymphatic and hematogenous dissemination of endometrial cells .
it has been offered as an explanation for rare cases of endometriosis occurring in locations remote from the peritoneal cavity .
in addition to pleural tissue , endometriosis has been reported in pulmonary parenchyma , bone , biceps muscle , peripheral nerves and the brain . the composite theory of the histogenesis of endometriosis combines the implantation , vascular / lymphatic metastasis and direct extension theories . in a previous report , the pancreas was located in the retroperitoneum and had no clear connection with the peritoneal cavity , a finding that endometrial fragments could be transported through lymphatic or blood vessels into such distant sites . because there are protean manifestations of endometriosis , it is likely that several mechanisms are involved in the pathogenesis .
further clinical and experimental investigations are needed to evaluate the pathogenesis of endometriosis occurring in unusual sites .
Output:
| pancreatic endometrial cyst is an extremely rare instance of ectopic endometriosis that was first described by marchevsky in 19841 ) .
a 21-yr - old woman with a history of epigastric pain and weight loss was found to have a cystic lesion in the pancreas on ct - scan . under the tentative diagnosis of a pancreatic cystic neoplasm
, partial pancreatectomy was performed .
histopathological examination of the specimen revealed cystic endometriosis .
the clinicopathological features of the lesion are discussed and literature concerning this extremely rare lesion is reviewed . |
PubmedSumm6525 | ***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: disease modeling in neuropsychiatric disorders implicates the role of abnormal cellular structure and function , resulting in consequential disturbances in synaptic signaling and discrete neural circuits .
a concatenation of research evidence underscores the role of genetic , epigenetic , as well as environmental pathogenic influences .
however , the specific pathoetiological mechanisms underlying the phenomenology of most neurological and psychiatric disorders have yet to be elucidated .
notwithstanding , convergent evidence indicates that alterations in neuronal integrity and function are mediated by abnormal central insulin signaling .
the critical role of insulin in normal and abnormal cns functioning provides the framework for characterizing its role in the pathoetiology , progression , and treatment of several neuropsychiatric disorders .
moreover , refining disease models for neuropsychiatric disorders , by evaluating the phenotypic and neurobiological overlap between neuropsychiatric disorders with metabolic disturbances , is an essential step in the development of personalized , preventative , and/or pre - emptive treatments .
this review broadly aims to underscore insulin 's salience to pathoetiological and therapeutic research in neuropsychiatric disorders . towards these aims ,
we review , herein , descriptive studies in human and animal models documenting the phenotypic overlap of psychiatric and neurological disorders with metabolic disturbances ; we also report on a pathophysiological nexus shared by neuropsychiatric disorders and metabolic disturbances with a particular emphasis on the interplay between insulin and central reward networks , stress , and neuroinflammation .
we also attempt to identify research vistas capable of empirically establishing a therapeutic role for targeting insulin and/or insulin - related pathways to generate novel correction strategies for select neuropsychiatric disorders .
the original association between disruptions in peripheral glucose metabolism and psychiatric disorders was documented approximately 400 years ago by thomas willis ( 1621 - 1675 ) .
he noted that diabetes often appeared among persons who had experienced stressful life events , sadness , or long sorrow . in 1899 , henry maudsley observed that diabetes and insanity are often co - expressed in families ( as quoted by ) .
one of the first systematic studies testing willis hypothesis was described in 1935 , by the american psychiatrist dr .
w. menninger , who postulated the existence of psychogenic diabetes and described a diabetic personality .
historically , insulin - shock therapy was observed to mitigate psychotic and affective symptoms ; unfortunately , safety concerns with insulin therapy appropriately resulted in its termination as an acceptable treatment modality .
it was also suggested that enhancing glucose metabolism and related insulin - signaling pathways in the brain improved functional activity of patients with schizophrenia .
major depressive disorder bardet - biedl syndrome ataxia - telangiectasia ( louis - bar syndrome ) woodhouse - sakati syndrome familiar hyperinsulinism kearns - sayre syndrome thiamine responsive megaloblastic anemia syndrome spinocerebellar ataxia 3 ( machado - joseph disease ) spinocerebellar ataxia 6 presently , accumulating evidence from human clinical studies demonstrates a bidirectional association between metabolic disturbances and neuropsychiatric disorders ( summarized in table 1 ) .
psychiatric disorders ( e.g. schizophrenia and bipolar disorder ) often co - occur with metabolic disturbances ( e.g. insulin resistance , type ii diabetes mellitus , obesity ) .
for example , individuals with depression have a higher risk of developing type ii diabetes mellitus by approximately 60% ( reviewed in , table 1 ) .
similarly , metabolic disturbances are reported to be two to four times higher in people with schizophrenia ( table 1 ) .
furthermore , psychotropic medications ( e.g. antipsychotics and antidepressants ) prescribed to individuals with psychiatric disorders are often accompanied by disturbances in metabolic parameters ( e.g. hyperglycemia , impaired glucose tolerance , type ii diabetes mellitus ( reviewed in [ 11 - 13 ] ) ) .
metabolic disturbances have also been implicated in neurodegenerative disorders ( e.g. alzheimer 's , huntington 's , and parkinson 's disease ) .
multiple clinical observations have demonstrated that dementia in general , and alzheimer 's disease in particular , is associated with type ii diabetes mellitus and obesity .
moreover , type ii diabetes mellitus is considered an independent risk factor for dementia , increasing the prevalence of dementia two - fold in diabetic populations [ 14 - 16 ] ( table 1 ) .
other clinical observations have shown that impaired glucose tolerance affects up to 80% of parkinson 's disease patients ( reviewed in ) ( table 1 ) .
the metabolic disturbances observed in individuals with parkinson 's disease may be linked to treatment .
for example , levodopa may induce hyperglycemia and hyperinsulinemia , whereas bromocriptine may increase insulin sensitivity .
likewise , the prevalence rates for type ii diabetes mellitus and insulin abnormalities are approximately seven - fold higher in patients with huntington 's disease when compared to healthy matched controls [ 20 - 22 ] ( table 1 ) . in addition
, clinical research in congenital neurodegenerative disorders suggests that more than 20% of those affected will develop metabolic complications , such as type ii diabetes mellitus and/or obesity ; moreover , convergent evidence suggests that these may be causative ( reviewed in ) ( presented in table 1 ) .
furthermore , age - related processes likely contribute to the underlying pathophysiological mechanisms of neurodegenerative disorders , via natural and chronic changes in whole - body metabolism ( i.e. insulin sensitivity ) , which may partially account for commonalities observed between neurodegenerative disorders and disturbances in metabolic profile ( reviewed in ) .
notably , starvation is also capable of inducing changes in emotional and behavioral brain functions .
for example , based on case reports and diary entries during natural periods of food shortages during war and famine , it has been shown that starvation was frequently accompanied by mental illness , including instances of depression , anxiety , psychosis and suicide .
similarly , eating disorders , such as anorexia nervosa and bulimia nervosa , are classified as serious mental illnesses with a mortality rate of 10% or higher ( reviewed in ) .
moreover , healthy controls exhibit psychopathology similar to those seen in patients with anorexia nervosa under conditions of starvation .
furthermore , dysfunctions in insulin signaling pathways have been implicated as part of the underlying pathophysiological mechanisms for both anorexia and bulimia nervosa ( reviewed in ) .
taken together , clinical studies have provided ample evidence describing an overlap between metabolic disturbances and neuropsychiatric disorders .
thus , pathophysiological changes in brain function and metabolic status coincide at a rate suggestive of a shared pathoetiology , suggesting that humoral factors ( discussed below ) are important as a part of this nexus ( figure 1 ) .
humoral factors , such as hormones and cytokines , circulate in the blood and serve as immediate and intermediate communicators between the brain and peripheral organs .
human and animal studies have shown that acute and/or chronic inflammatory processes and stress can trigger whole - body adaptation changes in the brain and peripheral organs ( discussed below ) .
stress ( e.g. hunger , childhood adversity , challenging life events ) has been implicated in the pathogenesis of obesity , addiction , and other psychiatric disorders .
the chronic activation of the hypothalamic - pituitary - adrenal axis , resulting in the overproduction of stress / glucocorticoid hormones , has been documented to be a consequence of abnormal negative feedback and reported in individuals exposed to trauma . moreover ,
an increase in glucocorticoid resistance has been found in more than 50% of mood disorder cases .
obese patients have increased levels of 11--hydroxysteroid dehydrogenase type 1 ( 11--hsd ; an enzyme which reduces cortisone to the active stress hormone cortisol following activation of glucocorticoid receptors ) , which has been reported to be a candidate biomarker for depression .
rats undergoing cyclic periods of caloric restriction and re - feeding , which sensitize them to stress - induced overeating , demonstrate compulsive - like consumption of palatable foods .
also , mice overexpressing corticotrophin - releasing hormone are characterized by increased food intake , weight gain , insulin resistance , increased anxiety , impaired learning , and altered adaptations to stress [ 41 , 42 ] .
abnormal levels of immunomodulating agents , such as cytokines , are associated with inflammatory processes in the brain and peripheral organs .
studies in humans and rodents have demonstrated that chronic inflammation may be a key factor in the pathogenesis of neuropsychiatric disorders and metabolic disturbances .
inflammatory cytokines , together with activated astrocytes and microglia ( i.e. neuroinflammation ) , have been found in patients with parkinson 's disease , alzheimer 's disease , amyotrophic lateral sclerosis , and multiple sclerosis ( reviewed in [ 43 - 46 ] ) .
cytokines have the capacity to influence the synthesis of neurotransmitters , including the release and reuptake of monoamines .
many groups have shown that elevated levels of inflammatory cytokines are found in individuals with mood disorders ( reviewed in [ 47,49 - 53 ] ) .
in addition , antidepressants are less effective in individuals with an active inflammatory state , and antidepressant efficiency may be enhanced when combined with agents known to affect the immune - inflammatory system ( e.g. acetylsalicylic acid ) [ 54 - 56 ] .
the aforementioned findings in humans were supported by animal studies , which have indicated that the systemic administration of pro - inflammatory cytokines ( e.g. tumor necrosis factor- [ tnf ] , interleukin-1 [ il1 ] and interleukin-6 [ il-6 ] ) in rodents induces sickness behavior associated with anorexia , sleep disturbance , neurocognitive impairment , fatigue , and reduced self - care behaviors ( reviewed in ) .
obesity is classified as a state of chronic low - grade inflammation ( reviewed in ) .
chronic obesity is associated with abnormal insulin , cytokine , and adipokine ( e.g. leptin and resistin ) function ( reviewed in ) .
postmortem studies of depressed patients who committed suicide revealed a down - regulation of leptin receptors in the frontal cortex .
circulating levels of resistin ( secreted by adipocytes and immunocompetent cells ) were associated with body mass index in patients with depression ; however , this may be the effect of antidepressant treatment , which has been shown to decrease resistin levels .
in addition , animal studies have demonstrated that toll - like receptor ( tlr ) signaling , which is a fundamental component in the innate immune system response , is implicated in mediating insulin and leptin resistance in the brain ( reviewed in ) .
for instance , obese diabetic mice with a mutation in the leptin gene ( ob / ob ) or leptin receptor ( db / db ) have demonstrated deficits in cell - mediated immunity . moreover , rodents on high - fat diets produce a local pro - inflammatory response that subsequently induces insulin resistance in the hypothalamus a state which may be reversed via the pharmacological inhibition of neuronal tlr signaling .
approximately 25% of total body glucose utilization is required for proper brain function , as glucose is the obligatory energy substrate of the brain ( reviewed in ) .
in contrast to peripheral organs where glucose can go through various metabolic pathways ( e.g. storage in the form of glycogen and lipids ) , the fate of glucose in the brain is determined almost entirely by oxidation ( reviewed in ) .
thus , similar to the periphery , glucose in the cns may proceed to the following : a. glycolysis , b. storage as glycogen , c. contribute to glycolipid / glycoprotein production , and/or d. serve as a progenitor to three principle neurotransmitters in the brain ( glutamate , gamma - aminobutyric acid [ gaba ] , and acetylcholine ) ( reviewed in ) .
the brain is traditionally viewed as an organ that metabolizes glucose independently of insulin ; however , this view has been challenged recently by several studies .
insulin receptors and insulin - sensitive glucose transporters ( e.g. glucose transporter [ glut]-4 and glut-8 ) have been identified in the cns on both neurons and astrocytes [ 70 - 72 ] .
also , insulin receptors , as well as downstream effectors of insulin , have exhibited similar patterns of distribution throughout the brain ( e.g. olfactory bulbs , hypothalamus , hippocampus , cortex , and cerebellum ) .
evidence also exists for insulin receptor expression in the substantia nigra , basal ganglia , and frontal cortex .
insulin 's ability to cross the blood brain barrier was evinced approximately four decades ago ; however , the amount of insulin capable of traversing the blood brain barrier varies across species and pathological conditions .
for example , acute hyperinsulinemia increases insulin concentration in the brain , whereas chronic hyperinsulinemia ( e.g. during type ii diabetes mellitus and obesity ) down - regulates insulin receptor expression in the blood brain barrier , characterized by central insulin resistance ( reviewed in ) .
both the presence of insulin receptors in the brain and insulin 's ability to cross the blood brain barrier suggest that insulin is required for normal brain function ( summarized in figure 2 ) .
neuronal ( central ) insulin signaling has been shown to have an important impact on the regulation of whole - body glucose metabolism and energy homeostasis .
insulin has catabolic effects on the brain , whereas it is anabolic at the level of peripheral insulin - sensitive tissues ( e.g. liver , fat tissue , and skeletal muscle ) ( reviewed in ) .
studies in rodents have shown that direct administration of insulin into the brain inhibits food intake ( i.e. anorexigenic effect ) and reduces body weight .
more specifically , the infusion of insulin into the ventral tegmental area in rats decreases food intake .
moreover , diminished insulin signaling in the brain has been associated with an orexigenic effect ( e.g. weight gain and peripheral insulin resistance ) [ 83,84,87 - 90 ] . the infusion of insulin ( or a small - molecule insulin mimetic ) into the third cerebral ventricle suppressed glucose production , independent of circulating levels of insulin and other glucoregulatory hormones .
studies using genetic manipulations of insulin receptors in the brain have illustrated the critical role of neuronal insulin signaling pathways in regulating feeding behavior and whole - body glucose metabolism ( summarized in table 2 ) .
for instance , mice lacking insulin receptors in the brain ( i.e. nirko ) develop insulin resistance and obesity phenotypes consistent with mice exhibiting hypothalamic - specific insulin receptor knockout . in the drug - inducible , brain - specific , insulin receptor knockout model
the deletion of insulin receptors from midbrain dopamine neurons in mice results in hyperphagia and increased body weight .
brain - specific insulin receptor substrate-2 ( irs2 ) knockout mice are overweight , hyperinsulinemic , and glucose intolerant results similar to those seen in conventional irs2 knockout mice .
moreover , the ablation of insulin receptors in the brain or liver of mice results in obesity- and diabetes - associated phenotypes , whereas the deletion of insulin receptors from adipose tissue produces the opposite effect ( i.e. weight loss ) ( reviewed in ) . taken together , these observations suggest that organ - specific regulation of insulin is used to maintain glucose homeostasis .
insulin also participates in reward circuits by regulating neurons of the mesolimbic dopamine - mediated pathway , implicated in the motivating , rewarding , and reinforcing properties of food ( reviewed in , figure 2 ) .
studies in human subjects have identified an imbalance of several neuronal circuits in obesity , which include aspects of reward - saliency , motivation , learning - conditioning , as well as the inhibitory control of emotional regulation and executive function ( reviewed in ) .
a novel hypothesis postulates that obesity is a consequence of addictive food behaviors ( reviewed in [ 98 - 101 ] ) .
obesity , which is often associated with insulin resistance , has been characterized by striatal dopamine-2 ( d2 ) receptor deficits .
leptin - deficient ( ob / ob ) mice are genetically obese and diabetic and also have low levels of tyrosine hydroxylase ( a rate - limiting enzyme in dopamine synthesis ) in their midbrain dopamine neurons .
these mice also have reduced dopamine release into the nucleus accumbens and decreased somatodendritic vesicular stores of dopamine in the ventral tegmental area .
treatment of ob / ob mice with dopamine-1/-2 ( d1/d2 ) receptor agonists reduces hyperphagic behavior , obesity , and improves insulin sensitivity . moreover , ob / ob mice show diminished sensitivity to the dopamine - dependent motivational and psychomotor stimulant effects of cocaine and amphetamines .
also , intracerebroventricular insulin administration increases the amount and activity of dopamine transporters in the substantia nigra .
diabetic rats have greatly diminished levels of dopamine in the midbrain and striatum , resulting in decreased sensitivity to the dopamine - dependent rewarding properties of amphetamines , compared with control rats with physiological levels of insulin .
moreover , inhibiting the irs2 in the midbrain attenuates the rewarding properties of cocaine and morphine in mice .
insulin and insulin - mediated signaling pathways also have an important role in the regulation of normal emotional and cognitive brain functions ( figure 2 ) .
for example , training for memory tasks in animals causes an upregulation of insulin receptors in the hippocampus .
historically , cognitive impairment has been associated with insulin resistance and type ii diabetes mellitus and was classified as diabetic encephalopathy . to take a more extreme case ,
individuals with alzheimer 's disease have a lower concentration of cerebrospinal fluid insulin and a higher plasma insulin concentration than controls , both of which indicate impaired insulin metabolism in the brain .
insulin treatment in individuals with alzheimer 's disease has produced beneficial effects on memory improvement and performance . in parallel , the systemic infusion of insulin has displayed improvements in verbal memory and selective attention in humans . moreover
, intranasal administration of insulin has been evinced to facilitate memory performance , and similarly acute intracerebroventricular insulin administration resulted in enhanced memory performance in rodents .
however , it is still unclear whether or not insulin has a direct effect on brain function or if these changes in brain function are a consequence of disturbances in peripheral glucose metabolism ( reviewed in ) .
growing evidence supports the notion that alzheimer 's disease could be conceptualized as a metabolic disease with progressive impairment of the brain 's capacity to utilize glucose , and respond to insulin and insulin - like growth factor ( igf ) stimulation .
indeed , insulin plays an important role in clearing -amyloid from the brain , which also regulated -amyloid levels by competitively blocking the insulin - degradation enzyme .
moreover , insulin treatment reduces the plasma concentrations of the amyloid precursor protein the precursor for the -amyloid peptide implicated in the development of alzheimer 's disease .
in addition , igf-1 has been shown to have a protective effect against the development of amyloidosis in tg2576 animals ( an animal model for alzheimer 's disease with a swedish double mutation of amyloid precursor protein : k670n
however , amyloidosis was promoted when mice developed high - fat diet - induced insulin resistance .
the aforementioned mouse models for brain - specific deletion of insulin signaling molecules ( e.g. nirko , as well as irs-2 knockout mice ) also display increased levels of phosphorylated tau , implicated in alzheimer 's disease .
normal and pathological conditions ( such as nutrients , oxygen , inflammatory factors , stress and hormones ) have immediate impact on brain functions .
moreover , neurons and glial cells exist in a tight mutual structural - functional relationship that depends on the peripheral supply of glucose as their major energy source .
insulin receptors are expressed in the brain , as such insulin can cross the blood brain barrier , affecting not only whole - body glucose metabolism , but also a wide range of normal brain functions , such as reward , motivation , cognition , attention , and memory formation ( figure 2 ) .
converging evidence indicates that insulin serves several critical roles in the cns under both normal and abnormal conditions .
thus , pharmacological targeting of insulin - related pathways may be beneficial in the normalization of brain functions .
it could be hypothesized that acute insults ( i.e. ischemia ) may immobilize compensatory pathways to protect and preserve normal neuronal function , whereas a chronic pathological state ( e.g. insulin resistance , obesity , inflammation or chronic imbalanced hormonal regulation ) may trigger decompensatory mechanisms that generate a perpetual cycle wherein the initial deregulation of central and peripheral glucose metabolism begins to affect neuronal functions , further exacerbating the underlying pathology .
moreover , it is important to take into consideration the role of humoral factors ( circulating in the blood ) , which act as immediate and intermediate communicators between the brain and peripheral organs , and their effects on homeostatic adaptations to stress and starvation .
the totality of evidence provides the basis for hypothesizing that these metabolic and neuropsychiatric disorders may share a common pathophysiological nexus .
critical effectors of this nexus include alterations in whole - body energy metabolism , oxidative stress , inflammation , insulin resistance , and corticosteroid signaling , as well as imbalances in cytokines and adipokines .
investigations that aim to refine the relative contributions of these effector systems , with a particular focus on convergent molecular pathways , may provide the basis for disease - related biomarker discovery , as well as novel treatment approaches for both metabolic and neuropsychiatric conditions .
roger s. mcintyre receives research grants from the following companies : stanley medical research institute , national alliance for research on schizophrenia and depression ( narsad ) , national institutes of mental health , eli lilly , janssen - ortho , shire , astra - zeneca , pfizer , lundbeck , forest and sepracor .
he is a member of the following advisory boards : astra zeneca , bristol - myers squibb , janssen - ortho , eli lilly , lundbeck , pfizer , shire and merck .
he is also a member of the following speakers bureaus : janssen - ortho , astra - zeneca , eli lilly , lundbeck , merck , pfizer and otsuka .
Output:
| evidence supporting the concurrence of metabolic disturbances ( e.g. insulin resistance , diabetes and obesity ) and neuropsychiatric disorders has been demonstrated in both human and animal studies , suggesting the possibility that they have shared pathophysiological mechanisms . during the past decade , our understanding for the role of insulin in both normal and abnormal central nervous system ( cns ) processes has become increasingly refined .
evidence indicates that insulin is a pleiotropic peptide , critical to neurotrophism , neuroplasticity , and neuromodulation .
moreover , the role of insulin underscores its importance in the development of several neuropsychiatric disorders , including , but not limited to , mechanisms involved in the pathogenesis and progression towards diabetes , obesity , and neurodegenerative disorders , such as alzheimer 's disease .
this review focuses on the insulin - mediated effects on normal and abnormal brain function and discusses why targeting insulin - related pathways in the brain may emerge as a new approach for refining treatment of neurological and psychiatric disorders . |
PubmedSumm6526 | ***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: the introduction of dihydroxyphenylalanine ( levodopa ) to the treatment of pd was a major scientific and clinical breakthrough in the treatment of this devastating disease .
second , comes the realization that an understanding of biochemical deficits can provide a clue as to how replacement , therapy could be successfully employed in neurodegenerative diseases , providing significant symptomatic benefit , if not a cure .
dopa had an enormous impact on attempts to treat other neurodegenerative disorders , particularly ad .
unfortunately , in spite of miraculous effects on patients with early and advanced pd and the motor benefits afforded to them , it soon became clear that dopa does not slow the neurodegenerative process and its effects are purely symptomatic .
consequently , the dopa dose required to control the motor manifestations must , be gradually increased as the disease progresses .
it quickly became clear also that , of the two dopa isomers , only the levorotatory stereoisomer , levodopa , produced therapeutic benefits , and chemical means to separate the two isomers were developed . in practice , only levodopa is now used in the treatment of pd , resulting in an improved safety profile . soon after came the recognition that some of the adverse effects associated with the drug were the result of peripheral - rather than central - conversion of levodopa into da , which , unlike levodopa , has significant autonomic activity .
since da does not cross the blood - brain barrier ( bbb ) , any da produced in the peripheral nervous system docs not contribute to the clinical benefits afforded by levodopa , and actually causes significant , adverse events , particularly gastrointestinal and other autonomic disturbances . the enzyme involved in the transformation of levodopa to da , ie ,
l - amino acid decarboxylase ( l - aad , initially called dopa decarboxylase ) is widespread in the body , with high concentrations in the liver .
two agents were developed that could inhibit , it , and both are still in use : carbidopa and benserazide . at .
present , practically all patients who require treatment with levodopa receive it as a fixed - dose combination with one of these inhibitors . of course , it is essential that levodopa be converted into da in the brain , and so the l - aad inhibitor should not cross the bbb .
the inhibition of peripheral l - aad has another result , which was initially unappreciated : it prolongs the biological half - life of levodopa ( and therefore also of da in the brain ) .
early on in pd , there is a dramatic beneficial effect of levodopa , described as the honeymoon .
as the disease advances and additional da neurons arc being lost , there is a need to compensate for this by increasing the daily dose of levodopa .
this is first , manifested by shortening of the duration of action of individual levodopa doses , called end - of dose effect or wearing off .
later on , other manifestations appear , including peak of dose dyskinesias and erratic responses to levodopa ( so - called unexpected on - off , or yo - yoing ) ( table i ) . while the exact mechanism responsible for this erratic response is still elusive , it is at least partly dependent upon pharmacokinetic factors such as plasma levels of levodopa . in particular , the phenomenon of wearing off , where the initial prolonged response to individual doses of levodopa is no longer maintained , limits the patients ' independence .
wearing off probably results from impaired capacity of the nigrostriatal da neurons and their terminals to uptake , store , and release da .
blockade of peripheral l - aad , which prolongs the biological half - life of the drug , can only incompletely compensate for this .
gait instability ( late ) depression ( early or late ) cognitive decline ( early or late ) autonomic dysfunction ( mainly constipation ) nonmotor problems ( eg , dementia , autonomic dysfunction ) fluctuations and/or drug - induced complications short duration response : delayed or partial on , wearing off , dyskinesias levodopa remains the gold standard of pd therapy .
however , several key symptoms of pd fail to respond to levodopa , or have a limited or unsatisfactory response ( table ii ) .
as discussed above , the long - term use of levodopa often leads to complications later in the disease ; wearing - off , dyskinesias , freezing episodes , and unpredictable on - off fluctuations are the most , problematic .
the pathogenesis and pathophysiology of these complications remain unclear , but it has been suggested that they are related to the toxicity of levodopa or its metabolites .
the pharmacokinetic and pharmacodynamic changes that take place as the disease progresses may be major contributors .
it has also been speculated that the complications may derive , at least in part , from the toxic effects of levodopa or da oxidative metabolites .
since levodopa alleviates the symptoms of the disease , accurate assessment of the patient 's real condition and monitoring of disease progression are problematic . at present ,
the only way to assess progression or deterioration is by withdrawing levodopa for a period exceeding 2 weeks .
obviously , this is not a practical solution particularly in the advanced stages of the disease and therefore our ability to monitor the rate of disease progression is limited .
positron emission tomography ( pet ) and single - photon emission computed tomography ( spect ) techniques are being developed and have shown significant correlations with global severity of pd .
catechol - o - methyltransferase ( comt ) is a ubiquitous enzyme that breaks down levodopa before it can be converted to da , as well as da itself .
comt inhibitors prolong the availability of a single dose of levodopa , without , delaying the onset of its effects , frequently reducing the total amount , of levodopa needed .
the present , indication for comt inhibition is as an adjunctive therapy to levodopa in advanced pd patients who have developed wearing off or on - off fluctuations .
however , comt treatment in the earlier stages of pd may also be worthwhile by preventing or delaying motor complications .
comt inhibition as a new treatment , strategy for pd has been recently comprehensively reviewed .
two comt inhibitors have been widely tested so far : tolcapone and entacapone . although motor fluctuations such as off periods are frequently reduced or eliminated by the use of tolcapone or entacapone , peak dose dyskinesias can be enhanced or precipitated , requiring a reduction in individual doses of levodopa .
tolcapone was recently removed from the market in most , countries due to presumed hepatic toxicity . however , the exact relationship to drug exposure is still ambiguous . on the basis of the rarity of these adverse events ,
some practitioners believe that its withdrawal was premature , arguing that the drug is possibly superior to entacapone ( although a direct comparison between the two has not been performed ) .
entacapone has a brief duration of action of approximately 2 h , ie , it has to be consumed with each levodopa dose ( or even more frequently ) .
preparations containing levodopa , entacapone , and a decarboxylase inhibitor in a single tablet or capsule could be beneficial , especially for patients who are treated with other drugs as well .
long - acting derivatives or sustained - release formulations of entacapone could also be advantageous .
da agonists ( daas ) have been an important tool in the treatment of pd for almost 40 years .
ttttc first , study of daas by calne et al constituted a milestone in pd therapy .
these drugs were introduced shortly after the discovery of levodopa and were initially thought to represent second- or even third - line agents .
ttttis was because they were effective in patients who had developed intolerance to - or side effects of - levodopa .
their initial use demonstrated not only their efficacy against rigidity and tremor , but also their dopa - sparing effects .
the possibility of reducing the dose of levodopa gradually became more important as the complications of chronic levodopa therapy were recognized , particularly dyskinesias and motor fluctuations .
the ability to replace some of the levodopa dose with a daa resulted in amelioration of these motor disturbances , also proving that they are not necessarily an unavoidable development in chronic pd .
attempts to use a daa as monotherapy in advanced cases of pd were deserted due to poor efficacy and the existence of side effects , while the trend toward using a daa as early therapy increased : by delaying the initiation of levodopa treatment , motor complications can be prevented .
several novel daas were tested and their utility was unquestionably demonstrated , although these studies proved that .
however , as the disease progresses , stronger da stimulation is required and , as increased daa dosages become limited by side effects , supplementation with levodopa becomes necessary , albeit again with the danger of the development of motor complications .
although there is no doubt , that daas can be used initially as monotherapy , the number of patients in whom this treatment can be maintained over long periods remains unclear . according to available data
20% of patients , and in 50% after 5 years .
while the ergot derivatives are clearly efficacious in pd , their use has been complicated by several side effects .
it was realized that ergots are dirty drugs , with the potential to interact with several types of receptors in the central nervous system , as well as in the periphery .
the development , of the synthetic daas piribedil , ropinirole , and pramipexole was an important further step . however , these agents shared a number of side effects .
it thus became clear that , while pleuropulmonary fibrosis may be specific to ergot derivatives , most of the complications of these therapies are class effects .
the motor fluctuations that characterize prolonged levodopa therapy are thought ( but . not proven ) to be related to the short , plasma half - lives of individual levodopa doses ( t1/2=90 min).thc clinical benefit from individual doses is longer , at least , in early stages of the disease , due to the buffering capacity of surviving da neurons , which transform levodopa to da , store it , and then release it in a tonic , rather than phasic , pattern .
the fact that daas do not depend on da neurons is a theoretical advantage , particularly at advanced stages of the disease when very few da neurons survive .
however , this advantage is related to their longer duration of action , typically 4 to 6 hours ( and much longer for cabergoline ) . if the nonsustained level of da stimulation is responsible for the development of motor fluctuations , these complications should be significantly delayed if cabergoline is to be used in de novo cases .
several studies have suggested that daas have additional beneficial properties , such as antioxidant or antiapoptotic effects .
notably , all these studies were performed in vitro , and therefore had a very short duration and used doses with unclear relationship to the clinical situation .
there are no available data indicating that daas have relevant antioxidant or antiapoptotic effects in routine clinical use in humans , or indeed that oxidative stress plays a major role in the pathogenesis of pd.the early addition of a daa prevents ( or at .
least delays ) the appearance of motor complications , but . whether this should be regarded as a neuroprotective effect
furthermore , even if daa can slow the progressive loss of da neurons in the substantia nigra , it would be very difficult , to prove it .
if daas do slow the progression of pd , a possible mechanism could be stimulation of presynaptic da receptors .
probably all da terminals contain receptors that mediate the synthesis and release of da by negative feedback .
reduction in the rate of da synthesis can thus be expected to slow the ongoing damage to da neurons .
most ( and probably all ) daas reduce the rate da of synthesis , but there is limited information on their relative efficacy in this regard . theoretically , a drug with relatively strong presynaptic stimulation ( relative to postsynaptic d2 stimulation ) , such as talipexole , should be preferred , although it is difficult to see how that advantage can be demonstrated in pd patients .
currently used daas include the ergot - derived or ergoline drugs bromocriptine , cabergoline , lisuride , and pergolide , with chemical structures based on ergot , a plant alkaloid . the newer , non - ergot synthetic daa , piribedil , pramipexole , and ropinirole - chemically unrelated to ergot - are being promoted vigorously .
side effects typical of all daas ( as well as levodopa ) include nausea , vomiting , dizziness , and orthostatic hypotension . at higher doses
, daas may induce confusion , hallucinations , and psychosis , although these usually appear in the advanced stages of the disea.se .
sedation and insomnia are other reported side effects of some daas , as well as of levodopa , and are probably not associated with any specific agonist .
attention has recently been drawn to somnolence as a possible adverse effect of daas ( including levodopa ) .
events of a compelling urge to sleep ( so - called sleep attacks ) have been observed in patients treated with daas .
this needs to be considered and explained to the patient , particularly if he or she is involved in activity in which the somnolence , even if not excessive , could endanger them or others .
some of the side effects specifically linked to the ergot derivatives include digital or coronary vasospasm , as well as pleuropulmonary and retroperitoneal fibrosis .
these are not associated with the newer and safer non - ergot daas piribedil , ropinirole , and pramipexole .
it has been found to reduce daily levodopa doses by 30% in a multicenter phase 2b trial in mild - to - severe pd .
apomorphine is the most , potent daa , and the only one that stimulates effectively both da d1 and d2 receptors ( as does da itself ) .
however , its therapeutic effect is hampered by its complex interindividual pharmaco - kinetics and pharmacodynamic variability and its narrow therapeutic range .
subcutaneous injections are very helpful , particularly for patients with prolonged off episodes .
is technically complex to use and expensive . in order to overcome these difficulties , several attempts to create individualized controlled delivery systems for apomorphine
in a recent study , a carboxymethyl cellulose powder of apomorphine was tested as intranasal sustained - release formulation .
these newer delivery systems will hopefully enhance its use as a rescue medication in severe cases .
there are at least , five types of da receptors , namely d1 , d2 , d3 , d4 , and d5 .
the role of d1 stimulation in the therapy of movement disorders , and particularly pd , has been debated for years .
bromocriptine is a d1 antagonist , pergolide a d1 agonist , while ropinirole and pramipexole do not interact with d1 receptors at all .
since all these daas have similar efficacy in pd , the role of d1 receptors in pd therapy is questionable .
however recent , reports suggest that the specific drstimulating drug , abt-431 , is also effective in pd .
thus , there arc several remaining issues in daa therapy ( table iii ) .
the efficacy of selegiline in the treatment , of pd is based on the assumption that inhibition of the monoamine oxidase b ( maob ) enzyme may prevent .
da neurotoxicity . the extensive datatop ( deprenyl and tocopherol antioxidative therapy of parkinsonism ) study demonstrated the safety and beneficial symptomatic effects of selegiline in early pd , but
it is possible that at higher therapeutic doses , maob inhibitors will not only ameliorate disease symptoms , but .
could also provide neuroprotection , which has been demonstrated in vitro with equivalent drug concentrations .
a new formulation of selegiline dissolves instantly in the mouth , eliminating the first - pass effect , in the liver , so that therapeutic levels are reached at an eighth of the daily regular dose of selegiline .
tms reduces the concentrations of amphetamine , the unwanted metabolite of selegiline , which otherwise limits the maximal tolerated dose .
rasagiline , another maob inhibitor , is presently being evaluated in clinical trials in the usa , europe , and israel . at .
doses up to 2 mg / day , rasagiline shows good safety and tolerability . it has a similar pharmacological profile to selegiline , but without amphetamine as a metabolite .
amantadine has been used for the treatment of pd for several decades , even though its mechanism of action is obscure .
recently , it was shown to function by inhibiting n - methyl - d - aspartate ( nmda ) receptors and found to be effective in reducing dyskinesias .
mcmantinc , a related drug , also functions as a neuroprotective agent through this mechanism .
memantine is used in germany as an antispastic drug and also to treat dementia , and is presently being evaluated for its effectiveness in pd , on the basis of preliminary results .
the antiglutamatergic effect of amantadine and memantine also suggests a neuroprotective action , and memantine is now actively promoted in ad .
although motor symptoms are the cardinal features of pd , most if not all patients will also manifest symptoms in other spheres . depression is particularly common and frequently antedates the motor disorder .
clinical experience shows that tricyclic antidepressants and selective serotonin reuptake inhibitors are very efficacious in this condition , with a dose and adverse event , profile similar to that of other patients .
amitriptyline , which has a marked antimuscarinic action , may adversely affect the constipation , while reducing the severity of parkinsonian tremor .
cognitive deterioration in pd may start , even before motor symptoms appear ( and is then trcndily termed
dementia with lewy bodies ) , but more frequently characterizes the advanced stages of the disease .
it is therefore not surprising that treatment with acetylcholinesterase inhibitors is effective in demented patients with pd .
delusions and hallucinations , usually visual , are frequent in advanced pd , particularly in demented patients .
obviously , classical neuroleptics can not be used since by blocking da receptors the parkinsonian symptoms would be exacerbated .
clozapine in particular is helpful in this situation , though its side effects and particularly the need for hematological monitoring are disadvantageous .
ouetiapine may be as useful , but other socalled atypical neuroleptics , and particularly olanzapine , are quite likely to induce motor exacerbation .
the most significant , of all is constipation , which commonly antedates the diagnosis and is frequently exacerbated by the antiparkinsonian drugs .
clinical experience again suggests that , the usual therapies ( eg , sildenafil for penile erectile dysfunction ) arc useful .
the management of pd is quite easy at the initial stages of the disease , where all dopaminomimetic drugs , as well as amantadine or selegiline ( or an antimuscarinic agent if tremor is the main problem ) , can be very efficacious .
as the disease advances , however , the motor complications become increasingly more severe and difficult to control , and require expertise and individual tailoring . at this stage , it is sometimes necessary to resort to functional neurosurgery . unfortunately , no drugs are yet available that slow the rate of progression of pd . the initial therapy for the motor symptoms should constitute a daa , which all have similar efficacy , though non - ergot daas arc probably safer . as the disease progresses and these agents become insufficient , levodopa can be added .
there is no clear role for selegiline and amantadine . in spite of the fact that these drugs are definitely effective and relatively safe
Output:
| parkinson 's disease ( pd ) is a common neurodegenerative disease .
while its cause remains elusive , much progress has been made regarding its treatment .
available drugs have a good symptomatic effect , but none has yet been shown to slow the progression of the disease in humans .
the most efficacious drug is levodopa , but it remains unclear whether the symptomatic benefit is associated with neurotoxic effects and long - term deterioration . the long - term problem associated with levodopa is the appearance of dyskinesias , which is significantly delayed among patients treated with dopamine agonists as initial therapy .
less clear is the role of other drugs in pd , such as monoamine oxidase inhibitors ( maois ) , including selegiline and rasagiline , the putative n - meihyl - o - aspartaie ( nmda ) receptor antagonists amantadine and memantine , and the muscarinic receptor blockers .
all these may be used as initial therapy and delay the use of dopaminergic drugs , or can be added later to reduce specific symptoms ( tremor or dyskinesias ) .
advanced pd is frequently associated with cognitive decline . to some extent , this can be helped by treatment with cholinesterase inhibitors such as rivastigmine .
similarly , hallucinations and delusions affect pd patients in the advanced stages of their disease .
the use of classical neuroleptic drugs in these patients is contraindicated because of their extrapyramidal effects , but atypical drugs , and particularly clozapine , are very helpful .
the big void in the therapy of pd lies in the more advanced stages .
several motor symptoms , like postural instability , dysphagia , and dysphonia , as well as dyskinesias , are poorly controlled by existing drugs .
new therapies should also be developed against autonomic symptoms , particularly constipation . |
PubmedSumm6527 | ***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 stimulus evoked electromyography ( emg ) is commonly used to confirm the accuracy of pedicle screw placement .
there are no studies to differentiate between solid screws and hollow screws to the electrical resistance of pedicle screws .
we speculate that the electrical resistance of the solid and hollow pedicle screws may be different and then a potential source of error with stimulus - evoked emg may happen .
resistance measurements were obtained from 12 pedicle screw varieties ( 6 screws of each manufacturer ) across the screw shank based on known constant current and measured voltage .
resistance of all solid screws ranged from 0.084 to 0.151 ( mean = 0.118 0.024 ) and hollow screws ranged from 0.148 to 0.402 ( mean = 0.285 0.081 ) .
there was a significant difference of resistance between the solid screws and hollow screws ( p < 0.05 ) .
the screw with the largest diameter no matter solid screws or hollow screws had lower resistance than screws with other diameters .
no matter in solid screws group or hollow screws group , there were significant differences ( p < 0.05 ) between the 5.0 mm screws and 6.0 mm screws , 6.0 mm screws and 7.0 mm screws , 5.0 mm screws and 7.0 mm screws , 4.5 mm screws and 5.5 mm screws , 5.5 mm screws and 6.5 mm screws , 4.5 mm screws and 6.5 mm screws .
the resistance of hollow screws was much larger than the solid screws in the same diameter group ( p < 0.05 ) .
hollow pedicle screws have the potential for high electrical resistance compared to the solid pedicle screws and therefore may affect the emg response during stimulus - evoked emg testing in pedicle screw fixation especially in minimally invasive percutaneous pedical screw fixation surgery .
the reported incidence of malpositioned pedicle screws in both cadaveric studies and clinical series has ranged from about 5% to as much as 40% , with potential consequences of construct failure , visceral injury , or neurologic injury.12345678 in traditional open instrumentation procedures , pedicle screws are placed free hand with the use of anatomic markers.910 the significant individual patient variation of pedicle anatomy can lead to difficulties in accurately placing pedicle screws.11 bony landmark deformities hamper the ability to obtain reliable fluoroscopic images .
furthermore , surgeons and operating room personnel are subjected to varying degrees of radiation when we use intraoperative fluoroscopy.12 recently , computer navigation has been reported to be more accurate , but this modality is time consuming , may lead to excessive radiation exposure and is not available in every institution because of its expense .
electrophysiological methods using intraoperative real - time electromyography ( emg ) recordings differ from the other modalities in that they provide functional data regarding the nerve roots , which are close to the pedicle screws .
in addition to advances in intraoperative monitoring , minimally invasive techniques have found increasing application in spinal surgery .
pedicle screws have been successfully placed by a variety of percutaneous techniques.1314 the risks in percutaneous pedicle screw placement are theoretically greater than open screw placement because of complete lack of direct visualization of landmarks or palpation of the medial pedicle and complete reliance on radiographic guidance . for this reason , emg testing may have even greater significance in percutaneous pedicle screw placement than open procedures .
the strong likelihood of a pedicle wall defect and a potential screw contact with a nerve root and/or the dura ranged from 6 ma to 11 ma.15161718 the electrical conductivity of pedicle screws may be one important variable that can affect the threshold .
different from solid pedicle screws mostly used in open surgery , pedicle screws used in minimally invasive surgery are mostly polyaxial hollow pedicle screws so that the pedicle screws can be inserted along the position and direction adjusted guiding needle .
to our knowledge , no earlier study evaluated effects of the hollow or solid screw design on its intrinsic electrical properties .
we have a hypothesis that the electrical resistance may be different between the solid and hollow pedicle screws , the difference may become a potential source of error with stimulus - evoked emg . in order to test and verify the hypothesis , resistance measurements were obtained from 12 pedicle screw varieties ( 6 screws of each manufacturer ) across the screw shank based on known constant current and measured voltage .
twelve titanium alloy ( ti-6al-4v ) pedicle screws from two different manufacturers [ table 1 ] commonly used in spine surgery were clamped by two aluminium clamps to provide a connection with the current source . a current meter ( hy1791 - 5s system direct current power supply , huaian yaguang electronic co , jiangsu , china )
was attached to the adjustable resistor with a current wire on each side and through a current wire to the pedicle screw .
two voltage wires that measured a current potential were attached 20 mm apart along the length of a screw ( the x1-x2 distance ) , using two aluminium clamps which has extremely low resistivity .
a current ( i ) measured using a multimeter ( uni - t ut60a - cn digital multimeter , uni - t technology co , china ) was passed through a screw via current wire .
generated voltage ( v ) was recorded using a voltmeter ( uj31 system direct current potentiometer , hangzhou jingke electronic co , zhejiang , china ) .
the resistance was calculated based on ohm 's law ( r = v / i ) ; where r is resistance of an object ( measured in ohms ; ) , v is a potential difference across an object ( measured in volts ) and i is a current through an object ( measured in amperes ) .
each screw was tested 5 times at respectively 50 ma , 100 ma , 150 ma , 200 ma and 250 ma to minimize a current selection bias error .
statistical analysis was carried out by using spss 15.0 ( spss / pc , chicago , il , usa ) software and anova .
as it is shown in table 1 , there are different categories of screw sizes from two different manufacturers : pedicle screws with diameter of 5.0 mm , 6.0 mm , 7.0 mm got from johnson company ( manufacturer a ) and pedicle screws with diameter of 4.5 mm , 5.5 mm , 6.5 mm got from medtronic company ( manufacturer b ) .
resistance of all solid screws ranged from 0.084 to 0.151 ( mean = 0.118 0.024 ) and hollow screws ranged from 0.148 to 0.402 ( mean = 0.285 0.081 ) , there was a significant difference between the solid screws and hollow screws ( p < 0.05 ) .
larger diameter screw had lower resistance than other diameter screws in solid screws or hollow screws group .
no matter in solid screws group or hollow screws group , there were significant differences ( p < 0.05 ) between the 5.0 screws and 6.0 screws , 6.0 screws and 7.0 screws , 5.0 screws and 7.0 screws , 4.5 screws and 5.5 screws , 5.5 screws and 6.5 screws , 4.5 screws and 6.5 screws .
resistance of all hollow screws was significantly larger than the solid screws with the same diameter ( p < 0.05 ) .
to prevent nerve root injury , investigators have sought ways to ensure that pedicle screws are confined within the bony cortex of the pedicle . in 1991 , calancie et al .
introduced intraoperative evoked emg recordings in a porcine model.19 the technique offered an objective means of evaluating pedicle screw placement . by applying an electrical stimulus through the pedicle screw , then recording the resulting evoked emg response , threshold values can help determine medially malpositioned screws .
now , the intraoperative electrical testing of pedicle screws is a widely accepted technique of minimizing intraoperative nerve root irritation or an injury during the insertion of spinal instrumentation.15161718 emg pedicle screw testing works by stimulating the placed screw and depending on the threshold needed to elicit a compound muscle action potential ( cmap ) from the corresponding myotome , an indication of pedicle breach can be determined . as the pedicle acts as an insulator , the higher the response threshold , the decreased likelihood of direct or near contact to the exiting nerve root . on the other hand , stimulation thresholds
the strong likelihood of a pedicle wall defect and a potential screw contact with a nerve root and/or the dura ranged from 6 ma to 11 ma.15161718 the electrical conductivity of pedicle screws may be an important variable that can affect the threshold.20 different from solid pedicle screws mostly used in open surgery , pedicle screws used in minimally invasive surgery are mostly polyaxial hollow pedicle screws so that the pedicle screws can be inserted along the position and direction adjusted guiding needle . to our knowledge ,
no earlier study evaluated effects of the hollow or solid screw design on its intrinsic electrical properties .
the current study showed that larger diameter screws from the same manufacture had lower resistance and more current flowed through it .
the results are consistent with a previous study.20 anderson et al.21 demonstrated that polyaxial pedicle screws have the potential for high electrical resistance between the mobile crown and shank and therefore may fail to demonstrate an emg response during stimulus - evoked emg testing in the setting of a pedicle breach .
furthermore , limthongkul et al.20 found there were no difference between different probe locations ( outer and inner mobile crown versus a screw 's shank stimulation ) and voltage through a screw .
a probable reason for that is that the equipment used in the study completed by limthongkul et al .
the measured screw resistances of hollow pedicle screws were larger than that of solid pedicle screws . by using a larger screw or solid
pedicle screw higher electrical current passes through it which might stimulate a nerve root earlier .
therefore , if higher threshold values are used intraoperatively , there could be a higher incidence of false positive measurements if larger diameter screws or solid screw are used .
a surgeon might accept even a lower threshold levels as a sign of an intact pedicle during the spinal cord stimulation .
therefore , in a large diameter screws or solid screws even lower threshold might not necessary indicate screw perforation through the pedicle cortex and a possible nerve root injury .
ozgur et al.22 pointed out that tapping often improved thresholds in emg testing to identify suboptimal screw trajectories in minimally invasive pedicle screw fixation , perhaps by compressing the bone and creating a denser , more insulative pedicle wall .
other potential pitfalls in neuromonitoring may be caused by an actual condition of a nerve root .
limbrick and wright23 showed that significantly higher stimulus intensities were required to evoke myogenic responses from chronically compressed nerve roots compared with normal nerve roots .
there were many studies about the utility of emg testing in percutaneous pedicle screw fixation techniques.222425 ozgur et al.22 used the initial fluoroscopically guided k - wires and the subsequent taps were insulated and stimulated via an automated emg system , then pointed out that emg testing helps to identify suboptimal screw trajectories , allowing for early adjustment and confirmation of improved placement .
bindal and ghosh24 pointed out that a continuous stimulation pedicle access needle alerts the surgeon to incorrect medial trajectories and may lead to safer pedicle cannulation .
wood and mannion25 pointed out that the combination of computer - assisted navigation combined with continuous emg monitoring during pedicle cannulation results in a low rate of pedicle screw misplacement .
furthermore , this technique allows reduction of the radiation exposure for the surgical team without compromising the accuracy of screw placement . through these techniques
it mainly focuses on the electrical resistance testing of the pedicle screws and discussion about the influence of pedicle screws to the stimulus - evoked emg .
other parameters with higher resistance that can interfere with an intraoperative spinal cord monitoring in vivo such as : pedicle cortical thickness , conditions of a recording nerve , conductivity of a muscle and thickness of a subcutaneous fat layer when using percutaneous cmap recording ; however , these factors were not examined in this study .
the question of clinical relevance of our data remains open and further research on this is needed .
based on the prospective clinical series some authors recommended that the pedicle tap nerve root stimulation threshold stimulus intensity below 12 ma or 15 ma is to be considered an indicator for a potential pedicle wall defect due to screw perforation and a possible contact of a screw with a nerve root.2426 the emg continuously stimulus intensity is set at 5 ma or 7 ma stimulus to monitor the lumbar nerve roots at the operated levels through the pedicle access needle.2425 the stimulation threshold stimulus intensities are not absolute when we use different stimulators such as pedicle tap and pedicle access needle with different intrinsic properties.242526 so we speculate that the difference of electrical resistance between the solid and hollow pedicle screws may become a potential source of error with stimulus - evoked emg . to avoid false - negative stimulus - evoked emg testing through the different design of pedicle screws such as solid or hollow pedicle
, the cathode stimulator probe should be applied to the pedicle access needle or pedicle tap with constant structure especially in the minimally invasive surgery , the technique may allow us the early adjustment and confirmation of improved pedicle screw placement trajectory . through the technique , we can see that the interference of screws can be avoided .
but the set of stimulation threshold need further investigation , future research should also look into other factors that might affect threshold stimulus intensity such as thickness and resistance of a pedicle cortex around the pedicle access needle or pedicle tap .
Output:
| background : although stimulus evoked electromyography ( emg ) is commonly used to confirm the accuracy of pedicle screw placement .
there are no studies to differentiate between solid screws and hollow screws to the electrical resistance of pedicle screws .
we speculate that the electrical resistance of the solid and hollow pedicle screws may be different and then a potential source of error with stimulus - evoked emg may happen.materials and methods : resistance measurements were obtained from 12 pedicle screw varieties ( 6 screws of each manufacturer ) across the screw shank based on known constant current and measured voltage .
the voltage was measured 5 times at each site.results:resistance of all solid screws ranged from 0.084 to 0.151 ( mean = 0.118 0.024 ) and hollow screws ranged from 0.148 to 0.402 ( mean = 0.285 0.081 ) .
there was a significant difference of resistance between the solid screws and hollow screws ( p < 0.05 ) .
the screw with the largest diameter no matter solid screws or hollow screws had lower resistance than screws with other diameters .
no matter in solid screws group or hollow screws group , there were significant differences ( p < 0.05 ) between the 5.0 mm screws and 6.0 mm screws , 6.0 mm screws and 7.0 mm screws , 5.0 mm screws and 7.0 mm screws , 4.5 mm screws and 5.5 mm screws , 5.5 mm screws and 6.5 mm screws , 4.5 mm screws and 6.5 mm screws .
the resistance of hollow screws was much larger than the solid screws in the same diameter group ( p < 0.05).conclusions : hollow pedicle screws have the potential for high electrical resistance compared to the solid pedicle screws and therefore may affect the emg response during stimulus - evoked emg testing in pedicle screw fixation especially in minimally invasive percutaneous pedical screw fixation surgery . |
PubmedSumm6528 | ***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: prepublication concerns , rumors , and the subsequent publication of two studies that reported the generation of mammalian - transmissible h5n1 virus in the laboratory have launched a passionate dialog among biomedical scientists about biosafety , biosecurity , and bioterrorism , not to mention the social responsibility of scientists . because of the language and intensity of the discussion , the influenza virology community agreed to a voluntary 60-day pause of any research that involved highly pathogenic avian influenza h5n1 viruses and led to the generation of viruses that are more transmissible in mammals . although originally planned for 60 days
, this self - imposed moratorium remains in place , and there is a great deal of pressure to continue the moratorium until the multiple issues that have been raised about this research and its implications are dispassionately discussed at the worldwide level .
the issues are not trivial . some argue that research of this kind pushes the limits of legitimate scientific inquiry .
others argue that the research is essential for world health , epidemic surveillance , and vaccine development .
the research is viewed in the broader context of genetic engineering and so - called dual - use research of concern ( durc ) . at a more fundamental level
, there is a need to explain both the benefits and the hazards of such research to the public .
i have been asked to take a historical perspective of these questions based on my active participation in the asilomar meeting of 1975 and my role as one of the original members of the recombinant dna committee charged with drafting the first recombinant dna research guidelines .
i think research on virus transmissibility is an essential focus of contemporary research not just for h5n1 but for all infectious agents .
how such experiments are performed needs to be discussed openly , with more attention paid to the science rather than to the rhetoric .
the university of wisconsin and erasmus university groups had their h5n1 mammalian transfer experiment work approved by their local institutional biosafety committee ( ibc ) and peer reviewed by nih . the work was clearly identified at the outset as being durc .
it was unknown at the time how their research would progress or if they would be successful .
however , based on what we learned at the time of the recombinant dna debate , i would argue that once the first ferret sneezed , it would have been prudent for the investigators to have initiated a self - imposed moratorium and , once again , address the consequences of their research with the ibc and the nih and plan a way forward . and
but the full implications of the work with regard to durc were not realized , and the world was treated to an unexpected announcement at an international virology meeting that h5n1 recombinants infectious to mammals had been created in the laboratory .
thus , i believe the moratorium should have been established sooner than it was and the work should have been subjected to a wider discussion of the broad issues facing science precipitated by the discovery of these recombinant viruses .
it is akin to the discomfort and self - imposed moratorium put in place when it was realized in 1974 that a recombinant dna molecule made in the laboratory with genes from the tumor virus sv40 , escherichia coli , and a bacterial virus was happily replicating in a strain of the human commensal bacterium , e. coli . at the time of the recombinant dna controversy , there was a moratorium on the cloning of toxins and certain genes from pathogens .
what is not as well remembered is that there was also a broad moratorium on cloning certain eukaryotic genes , for example , insulin into e. coli , until such time that the experiments could be done in an approved safe vector and safe host .
it took several years before these prerequisites were available , and the moratorium remained in place until that time .
even when these experiments could be safely performed , the first experiments were done under biosafety level 3 ( bsl3 ) conditions rather than at the more secure bsl4 .
the adoption of safe laboratory practices and the training necessary to conduct these experiments safely were implemented worldwide .
the inclusion of nonscientists in forming these policy decisions strengthened and legitimized the efforts and led to an increased public awareness of this research and a more general willingness to accept biological research using dna technologies .
the entire process was open to reporters and journalists to keep the public updated with the decisions that would potentially guide the creation of new organisms and protect the environment .
i think that one answer to the dual - use problem and the dark specter painted by the critics of genetic engineering , including the h5n1 experiments , is the immediate implementation of training for investigators in the principles and practices of research that may have public health or social consequences .
it will also be necessary to discuss and understand the risks posed by the information generated by the work rather than the risks posed by the physical agent or material ( i.e. , biosecurity rather than biosafety ) , a concept new to many of us .
critics have asked , why did no one in authority at the nih or at the institutions where the research was conducted think through the consequences of this research before it was given the go - ahead ?
i think when these matters arise , the responsibility must be placed on the individual investigator .
the ibc , the study sections , and grant program oversight are only as effective as the information provided by the investigator .
once we train a generation of young scientists in what constitutes responsible research that may have unintended social consequences , it will become part of the research culture , as did the recombinant dna guidelines .
every concerned biomedical scientist can begin to educate themselves and , more importantly , their students , staff , and colleagues now .
the training materials already exist and can be employed to educate the lay public and the future members of an ibc and study section .
in my view , this should not be a government - initiated or -driven program but rather a standardized program devised by working scientists and the professional organizations to which they belong .
the success of scientific leadership during the recombinant dna debate of the mid-1970s was the result of a progression of experience , new technology , and education .
this can be accomplished again even as more complex technology is available and the ability to alter the gene pool of the planet becomes experimental reality .
the study of genomes of all living ( even once living ) things and their manipulation dominates much of contemporary research and thought in biology .
it has altered both the way scientific questions are formulated and the way experiments are designed and carried out .
it must be approached thoughtfully using , one hopes , common sense as well as scientific creativity . in spite of widespread consternation among many scientists about the validity of the concerns ,
recall that one goal of the self - imposed recombinant dna moratorium was to provide time for an international conference(s ) to be organized that would evaluate the state of the new technology and the risks associated with it .
this is a new time , and an analogous event that calls for similar action .
it is also a good time for scientists to learn how to talk effectively to the public and , in an age of instant reporting , to the press and media .
finally , i should note that , in my mind , this current debate is not so much an issue about the freedom of scientific inquiry and the dissemination of scientific research as it is about the social responsibility of science and scientists . the ( very privileged ) social contract by which science is sustained depends on the public continuing to understand why this work is beneficial and worthwhile .
Output:
| abstractin mid-1974 , soon after the first recombinant dna molecules were replicated in escherichia coli , scientists called for , and observed , a voluntary moratorium on certain experiments . one goal of the moratorium was to hold a conference ( asilomar ) to evaluate the risks , if any , of this new technology .
the asilomar conference concluded that recombinant dna research should proceed but under strict guidelines .
the furor surrounding the recent genetic manipulation of the transmissibility of avian influenza virus h5n1 led to a short - term moratorium that has been extended indefinitely .
the question is how long should the moratorium remain in place , or should it be permanent ?
voltaire observed ,
history never repeats itself ; man always does .
i believe the parallels of asilomar can be applied to the problem facing biomedical science today .
we should move forward to establish standardized guidelines , using common sense and scientific creativity .
the onus of responsibility falls on the individual scientist and involves the education of a new generation of scientists into the social and ethical implications of genetic engineering in a new age of genomics and synthetic biology .
in addition , scientists who work with infectious agents must deal not only with biosafety but also , alas , with bioterrorism .
the h5n1 affair is not a question of freedom of inquiry or the dissemination of scientific research ; it is a question of the social responsibility of science and scientists to ensure that the public understands why this work is beneficial and worthwhile . |
PubmedSumm6529 | ***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 caries is still a highly prevalent pathology in the worldwide population despite all the traditional and original prevention methods . in spite of dramatic improvement in the caries status of children , dental caries
although fluorides are highly effective in prevention of caries on smooth surfaces , they are not equally effective in protecting the occlusal surfaces .
permanent posterior teeth construct about 90 percent of carious lesions of the pits and fissures .
molars are the most vulnerable tooth type for this defect . the application of pit - and - fissure sealants is considered as the most appropriate treatment modality for prevention of occlusal caries .
therefore , the retention rate becomes a determinant of their effectiveness as a caries preventive measure .
sealants are rarely retained completely over the tooth s lifetime and must be reapplied . even under proper application conditions , 5 to 10 percent of sealants
are lost annually . in order to enhance the longevity of pit - and - fissure sealants , several materials and techniques
have been evolved , among which is the use of flowable composite resins as pit - and - fissure sealants [ 811 ] .
the higher filler content causing decrease in the surface wear is the main logic for using flowable composites as pit - and - fissure sealants .
however , there are few clinical studies comparing the retention of these materials with that of conventional resin based sealants .
the purpose of this study was to compare the retention of a conventional resin - based sealant and a flowable composite resin placed on occlusal pits and fissures over a 12-month period .
children in the age range of 6 to 9 years having caries free , fully erupted first permanent molars were included in this study . written informed consent was obtained from the parents or guardians of all children in the study , and the study design was approved by the ethics committee of the school of dentistry , university of isfahan .
prior to examination , the occlusal surfaces were first cleaned by pumice prophylaxis to remove the dental biofilm and stains .
the teeth were examined by a trained clinician ( mj ) using a flat mirror and a who probe to confirm the absence of decay .
a total of 40 children were recruited , providing a sample size of 80 teeth .
the occlusal surfaces were etched with 37% phosphoric acid for 20 seconds , rinsed with air / water spray for 15 seconds , and dried with a mild air stream for 20 seconds until a uniform whitened surface with chalk - like appearance was obtained . in cases of saliva contamination ,
a 5-second re - etch was performed . a layer of light - cured single - component adhesive ( excite , ivoclar vivadent inc .
amherst , ny , usa ) system was applied to the acid - etched surface and light cured for 20 seconds . using a half - mouth design , a conventional light - cured resin - based pit - and - fissure sealant ( concise light cure white sealant , 3 m espe , st .
paul , mn , usa ) was applied on randomly assigned first permanent molar on one side of the mouth , and a light - cured flowable composite resin ( filtek supreme xt flowable restorative , 3 m espe , st .
the teeth assignment was done using a coin toss . for the teeth sealed with conventional fissure sealant ,
the sealant was applied to the occlusal surface and light cured for 40 seconds using a conventional visible light - curing unit at 450 mw / cm output ( coltolux 2.5 , c7906 , colten , usa ) . for the teeth sealed with flowable
composite , the flowable resin was applied to the occlusal surface and light cured for 40 seconds .
after each application , the sealant was tested for lack of air bubbles , marginal adaptation , retention , and complete polymerization and if it was deficient , the tooth was re - treated .
the children were re - examined at 3 , 6 , and 12 months after the sealant application , using an explorer and flat mirror .
evaluations were performed by a trained clinician ( mj ) , who was blind to the treatment group assignments .
sealants were classified as present , partial loss or complete loss , following the criteria proposed by garca - godoy .
the statistical analysis was performed using spss windows 11.0 ( spss inc , chicago il ) , using wilcoxon test at 5% significance level .
table 1 displays the distribution of sealant retention rates after 3 , 6 and 12 months for the two materials . for both materials
after three months , 38 teeth sealed with either conventional fissure sealant or flowable composite were completely intact .
after six months , 36 teeth sealed with conventional fissure sealant and 37 sealed with flowable composite were still intact .
after 12 months , 33 teeth sealed with conventional fissure sealant were intact compared to 35 sealed with flowable composite .
the wilcoxon test revealed no statistically significant difference regarding retention rate between the two materials after three ( p>0.05 ) , six ( p>0.05 ) and 12 months ( p>0.05 ) .
although the use of pit and fissure sealant has been effective in preventing occlusal caries for more than two decades , there remained the concern that the sealant had broken away .
it has been reported that the higher amount of filler particles of flowable composites provides lesser porosity and better wear resistance than conventional resin based sealants .
however , the conventional fissure sealant has enhanced flowing properties . it can be argued that this property allowed the conventional fissure sealant to penetrate deeper into the fissure and may therefore be better retained .
however , a study by kakaboura et al showed that a low - viscosity resin composite also penetrates more in shallow - wide fissures compared to the conventional resin sealant .
our study supports findings from earlier studies that the success rate was similar between the two materials [ 810 ] .
a similar trend was observed in a study by corona et al , where the complete retention was 95% for conventional pit - and - fissure sealant and 100% for flowable composite over a one - year follow - up period . in a study by koch et al ,
a flowable restorative system was compared to a conventional filled sealant , and 30 out of 31 teeth sealed with an unfilled resin were completely intact compared to 28 out of 31 teeth that were sealed with the filled resin after 12 months .
contrary to our findings , autio - gold observed slightly lower retention rates in teeth sealed with a medium - filled material when compared with an unfilled sealant ( delton ) , but the difference was not statistically significant .
the complete retention at 12 months was 89.7% for the flowable composite and 84.6% for the conventional sealant .
several authors have reported that after one - year , sealant retention is about 8595% , which might be considered as a clinical success [ 1921 ] .
although the total study period of 12 months seems short for the evaluation of the retention rates , according to dennison et al , most sealant failures occur at six months following application . in order to overcome the inter - operator variability , the two materials were applied in every child .
the selection of material for each quadrant was randomized and the evaluation process was blind , further minimizing the possibility of bias .
overall , it may be concluded that the conventional pit - and - fissure sealant and the flowable composite resin presented similar results in terms of retention . however , because of the scarcity of clinical studies on the use of flowable composite resins as sealants , further studies are warranted that include other flowable composite resins , children of different ages , and longer follow - up periods .
Output:
| objective : long - term retention of pit and fissure sealants is crucial for their success .
this clinical study evaluated the retention rate of a flowable composite resin ( filtek supreme xt flowable restorative ) compared to a conventional resin - based sealant ( concise light cure white sealant ) over 12 months.materials and methods : forty subjects aged 6 to 9 years were included in the study . using a half - mouth design ,
a total of 80 first permanent molars were sealed with conventional fissure sealant on one side of the mouth and flowable composite on the contralateral side .
clinical evaluation was performed at 3 , 6 , and 12 months by a single blind examiner and the retention was classified as complete retention , partial loss , or total loss.results:for both materials , there was no total loss of sealants over 12 months .
partial loss of both materials was observed in one sealant after 3 months .
after 6 months , 36 teeth sealed with conventional fissure sealant were intact compared with 37 sealed with a flowable composite , and after 12 months , 33 teeth sealed with conventional fissure sealant were intact compared with 35 that were sealed with a flowable composite .
there were no statistically significant difference ( p>0.05 ) between the two materials regarding the retention rate at each follow - up period.conclusion:as flowable composite resulted in comparable sealant retention rates , this material could be a good choice for fissure sealant . |
PubmedSumm6530 | ***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: decubital ischemic fasciitis is a rare entity occurring mostly in the elderly and in debilitated patients , in the deep subcutaneous tissue , at pressure points or bony prominences.[14 ] it can simulate a soft - tissue sarcoma clinically and histopathologically.[14 ] imaging helps to rule out malignancies and therefore to prevent unnecessary interventions .
a 72-year - old woman presented with a palpable mass over the right hip region .
physical examination revealed a 4- to 5-cm , hard , and fixated mass in the right proximal thigh , located posterolateral to the greater trochanter .
mri revealed diffuse hyperintense signals on the t2w images [ figures 1a and 1b ] consistent with edema and inflammation , in the muscles and subcutaneous tissues , with prominent , peripheral , and ill - defined enhancement [ figure 2 ] , over an area measuring approximately 4 - 7 cm , at the level of the greater trochanter .
a ct - guided needle biopsy showed coagulative necrosis , hemorrhage , and fibrosis involving the adipose tissue .
the capillary and muscular vessels within the lesion also showed fibrinoid necrosis in their walls , without evidence of primary vasculitis [ figure 3 ] .
these findings , along with the clinical features , were considered compatible with the diagnosis of ischemic fasciitis ( atypical decubital fibroplasia ) .
axial ( a ) and coronal ( b ) fat - suppressed t2w images show diffuse hyperintense signals ( arrows ) in the muscles and subcutaneous tissues , adjacent to the right greater trochanter axial contrast - enhanced t1w , fat - suppressed mri shows subtle , peripheral enhancement ( arrow ) in an area measuring approximately 47 cm , at the level of the greater trochanter histopathologic slide ( h and e stain ) shows coagulative necrosis and hemorrhage with capillary and muscular vessels showing fibrinoid necrosis in their walls ( arrows )
decubital ischemic fasciitis , also called atypical decubital fibroplasia , is a distinctive fibroplasia occurring predominantly in the elderly and debilitated patients , confined to bed or wheelchair - bound.[13 ] the lesions occur in the deep subcutaneous tissue at pressure points or bony prominences .
it is a rare condition , and 40 cases have been reported in the literature until 2009 .
ilaslan et al . have reported the mri features of decubital ischemic fasciitis in three patients . on mri ,
the mass - like area in our patient was isointense compared to muscle on the t1w images , and hyperintense on the t2w images .
after administration of gadolinium , subtle and peripheral enhancement was seen in the subcutaneous and muscular tissues .
the bone adjacent to the affected soft tissue ( greater trochanter ) was not involved .
lesions occurring in the shoulder , sacral area , posterior chest wall , and vulvovagina have been reported .
the diagnosis of decubital ischemic fasciitis with typical findings on mri prevents the already debilitated patient from undergoing further and unnecessary interventions .
consideration of this entity by the clinician and the radiologist helps the pathologist rule out malignancy .
we want to point out that since mri is a common and appropriate imaging method used to examine soft - tissue masses , all radiologists , especially those evaluating musculoskeletal mri examinations , should be aware of this entity and be familiar with the clinical features , common locations , and mri findings .
Output:
| the mri findings in a case of decubital ischemic fasciitis located posterolateral to the right greater trochanter , in a 72-year - old woman , are presented .
decubital ischemic fasciitis is an uncommon entity encountered mostly in debilitated , elderly patients , in the deep subcutaneous tissue , at pressure points or bony prominences .
it can simulate soft - tissue sarcomas .
recognition of this lesion radiologically is important to prevent unnecessary interventions . |
PubmedSumm6531 | ***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: therapeutic lifestyle interventions tlss are recommended as an essential component of the initial and lifelong therapeutic regimen for the majority of individuals with or at risk for type 2 diabetes .
tls interventions consist of dietary and exercise recommendations that promote weight loss in overweight and obese individuals with the ultimate goal of reducing risk for cardiovascular disease cvd , the primary contributor to early morbidity and mortality in type 2 diabetes . despite the implied importance of the influence of tls on promoting glycemic and metabolic control and ultimately reducing risk for cvd events
, there were no long - term randomized controlled clinical trials investigating the impact of diet and exercise on cvd outcomes . until recent publication of the results of the look action for health in diabetes ahead trial
, the majority of intervention studies have focused on achieving strict levels of glycemic control using existing pharmacologic therapies as a way of addressing cvd risk . the failure to observe reductions in cvd outcomes with intensive pharmacologic strategies in several recent large clinical trials supported the need to investigate the contribution of tls recommendations on amelioration of risk for macrovascular complications .
the primary objective of look ahead study was to examine the long - term effects of an intensive lifestyle intervention program in overweight subjects with type 2 diabetes when compared with a control group receiving diabetes support and education .
the primary outcome was a composite of the first postrandomization occurrence of fatal and nonfatal myocardial infarction and stroke .
the study was powered to detect an 18% difference in cvd events between the two groups at 13.5 years of follow - up .
due to the observation of fewer events than anticipated , angina requiring hospitalization was added to this composite measure during the second study year .
look ahead randomized 5145 participants with type 2 diabetes between the ages of 45 and 74 years to an intensive lifestyle intervention or control group .
the mean age was approximately 59 years and the mean body mass index was 36 kg / m .
randomized subjects were under reasonable levels of glycemic control with mean baseline a1c values of < 7.5% .
women accounted for 60% of participants and only 16% of subjects were treated with insulin at time of study entry , fulfilling the prespecified recruitment goal of < 30% of insulin - treated subjects .
all participants were required to complete a maximal exercise stress test prior to randomization to ensure safety of the exercise intervention .
retention of participants was high throughout the mean follow - up time period of approximately 10 years , with less than 4% of subjects being lost to follow - up .
the ability to maintain retention in the look ahead study can be attributed in part to the intensive screening process that required candidates to keep detailed records of food intake and physical activity during a 2-week lead in period .
this resulted in the inclusion of subjects who were both motivated and willing to perform self - monitoring of caloric intake and physical activity .
the intensive lifestyle intervention was designed to allow participants to achieve and maintain a 10% weight loss through a combination of a decrease in caloric intake and an increase in physical activity [ table 1 ] .
energy intake was restricted to 1200 - 1800 calories per day according to body weight .
food choices were limited by use of meal replacement strategies for two meals a day for the first 6 months and one meal a day for the next 6 months .
regular meetings with nutritional support personnel guided participants toward sensible meal planning with encouragement of the intake of fresh fruits and vegetables .
components of the intensive lifestyle intervention in look ahead exercise prescriptions encouraged 175 min or more of moderate intensity physical activity per week in sessions of at least 10 min duration .
all intensive lifestyle intervention participants received pedometers and with a goal of 10,000 steps each day .
all participants were assigned to a lifestyle coordinator . to ensure compliance with both caloric and exercise interventions , meetings with nutritionists , exercise , and behavioral specialists
were held on a weekly basis for the first 6 months with a gradual tapering of frequency to at least one in - person or phone contact per month .
periodic refresher courses and national campaigns were introduced to reemphasize the principles of the intensive intervention .
participants randomized to the control group received three group educational and social support sessions per year .
these sessions focused on diet and nutrition , exercise , and issues related to living with diabetes .
control group participants were seen at annual visits and received periodic phone calls to encourage continued participation in this long term clinical trial .
significant differences were observed between the intensive lifestyle intervention and control groups at 1 year .
weight loss -8.6 vs. 0.7% , p < 0.001 and fitness levels + 20.9 vs. 5.8% , p < 0.001 were greater in the intensive lifestyle intervention group .
there were associated reductions in a1c and cardiovascular risk factors , providing a clear separation between the intensive lifestyle intervention and control groups in anticipation of meeting prespecified criteria for the primary outcome .
however , these differences in weight reduction and fitness did not translate into long - term reductions in cvd outcomes .
the look ahead intensive lifestyle intervention was ended in september 2012 , when no group differences were observed in cvd events as the primary composite endpoints .
a total of 403 intensive lifestyle intervention and 418 control group participants experienced the primary outcome .
these differences were not significant as a composite , or when broken down into secondary or other individual cvd events , despite sustained differences in weight loss and fitness levels between the two groups .
subgroup analyses revealed fewer cvd events in intensive lifestyle intervention group participants with no history cvd at baseline , and more events in those with a history of cvd at baseline .
subgroup analyses based on gender or ethnicity also failed to demonstrate any group differences in outcomes .
the failure to observe differences in cvd events either in all participants or among specified subgroups raises the question as to whether look ahead represents another negative intervention study in type 2 diabetes .
this issue is likely to cause debate and commentary in coming years , but it is worth looking at some of the prespecified secondary objectives for look ahead .
these secondary objectives included an examination of the effect of intensive lifestyle intervention on diabetes control and complications albuminuria / amputation ; measures of physical activity and fitness , dietary intake , body weight , blood pressure bp , lipids , obesity - related cancers ; osteoarthritis symptoms and disability ; sleep apnea ; urinary incontinence ; gall bladder disease ; fracture risk and bone mineral density ; and quality of life and psychological outcomes .
it is in through an examination of these secondary outcomes that look ahead offers important information that supports efforts to promote intensive lifestyle intervention among individuals with type 2 diabetes .
participants randomized to ils had greater reductions in a1c , lost more weight , had greater reductions in waist circumference , a greater increase in fitness levels , and more mobility with less disability than those receiving diabetes support and education .
similar to what has been observed in earlier studies , these favorable changes were most marked at 1 year but differences were maintained for the duration of the study .
for example , the initial 8.6% weight loss in the intensive lifestyle intervention group at 1 year was followed by a period of weight regain through year 5 , following which there was a gradual decline with a sustained weight loss of 6.5% at the end of the study .
fitness levels also peaked at 1 year followed by a decline over the next 4 years ; however , fitness levels remained above baseline values in the intensive lifestyle intervention group , while a decline was observed in the control group .
other benefits observed with the intensive intervention in look ahead included favorable changes in sleep apnea , urinary incontinence , and health - related quality of life hrql .
the sleep ahead study enrolled 264 subjects from four centers who were representative of the overall look ahead population .
subjects in this substudy had evidence of obstructive sleep apnea ( osa with a baseline mean apnea - hypopnea index ahi of 23.2 16.5 events per hour .
participants receiving the intensive lifestyle intervention experienced a decrease in ahi events of 9.7 2.0 events per hour when compared with the control group .
these improvements were directly related to weight loss with greatest improvements observed in participants losing 10 kg body weight . in women ,
the prevalence and incidence of urinary incontinence was reduced among those receiving the intensive lifestyle intervention at 1 year .
changes in hrql using the 36-item short - form health survey and beck depression inventory ii bdi - ii scale demonstrated improvements in the physical component measures of hrqol and bdi - ii scores in the intensive lifestyle intervention group .
an investigation into adverse events was conducted to determine in these may have been affected by the intensive lifestyle intervention . although medical management was relegated to a participant 's physician , adjustments were made to diabetes medications to offset risk for hypoglycemia in the intervention group .
there were no observed group differences in the frequency of hypoglycemia , fractures , amputations , congestive heart failure , or occurrence of gallstones .
these findings support the safety of interventions that promote weight loss through caloric reductions and increased physical activity in obese and overweight individuals with type 2 diabetes .
the focus on cvd events as the primary outcome can blur the benefits that were observed with the intensive lifestyle intervention program in look ahead .
the intensive lifestyle intervention was associated with improvements in glycemic control , mobility , osa , hrql , and urinary incontinence in women .
more participants in the intensive lifestyle intervention group experienced remission of their diabetes , which may have accounted for higher levels of low - density lipoprotein cholesterol and the less frequent use of ace inhibitors and angiotensin receptor blockers in this group .
remission of diabetes was more likely in those with a shorter disease duration and lower baseline a1c , suggesting that the presence of residual beta cell function may be necessary to maximize the effects of exercise on glycemic control .
greater reductions in systolic bp and increases in high - density lipoprotein cholesterol were observed with intensive lifestyle intervention .
waist circumference , a measure of central obesity , was reduced , as was the incidence and prevalence of depression .
while these changes do not satisfy the requirements for a positive study , they do provide validation of including tls as a major component of therapy in type 2 diabetes . in summary ,
an intensive lifestyle intervention focused on weight loss did not reduce the rate of cardiovascular events in overweight or obese adults with type 2 diabetes .
however , significant improvements were observed in cvd risk factors , sleep apnea , depression , and quality of life .
one important aspect of therapy in individuals with type 2 diabetes is to promote well - being as those who live with this disorder deal with the multicomponent therapy required to achieve metabolic control .
although the intensive lifestyle intervention has been discontinued , look ahead participants continue to be followed to determine the long - term effects of the intervention on health outcomes .
it is likely that we will learn more about these effects in the coming years .
Output:
| the look action for health in diabetes ahead study was designed as a long - term randomized controlled clinical trial and powered to detect differences in cardiovascular outcomes , the primary cause of early morbidity and mortality in type 2 diabetes , among subjects randomized to receive an intensive lifestyle intervention or a control group of diabetes support and education .
the study was terminated early due to the absence of any difference in the primary outcome , defined as a composite of the first postrandomization occurrence of fatal and nonfatal myocardial infarction and stroke , or angina requiring hospitalization . however , important secondary favorable outcomes were observed in those receiving the intensive lifestyle intervention .
this included more weight loss , greater fitness , less disability , less depression , reductions in sleep apnea and urinary incontinence , better glycemic control , and more subjects experiencing diabetes remission .
these results underscore the importance of lifestyle interventions as a component of diabetes therapy .
long - term follow - up of look ahead participants is planned , despite discontinuation of the intensive lifestyle program . |
PubmedSumm6532 | ***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 acquired dacryocystocele is a diffuse and centrifugal enlargement of the lacrimal sac that forms as a result of obstruction of lacrimal drainage system proximally at the level of the common canaliculus and distally at the level of nasolacrimal duct .
findings associated with dacryocystocele are irreversible fibrotic narrowing in the lacrimal system , osseous changes in the nasolacrimal duct and chronic and low - grade inflammation . adult dacryocystoceles are often observed after dacryocystitis ; however , they may also develop idiopathically or due to autoimmune fibrous diseases , sinusitis and paranasal sinus mucoceles , after trauma or osseous configuration in the dysplastic duct wall and tumors , or secondarily to dacryocystorhinostomy surgeries . in computerized tomography ( ct ) and magnetic resonance imaging ( mri ) ,
a dacryocystocele appears as a fluid collection that is separated from other solid structures by a thin rim .
differential diagnosis includes malformations of the lacrimal sac , diverticulum , dermoid and epidermoid cysts , encephalocele , primary epithelial tumors of the sac , and external tumors . in this study
, we aimed to determine the probable etiology as well as clinical , microbiological , histopathological , and radiological findings of dacryocystoceles in acquired dacryocystocele cases . to our knowledge , this is one of the largest case series published of acquired dacryocystoceles in adult patients .
in the study , the charts of patients who had undergone external dacryocystorhinostomy ( edcr ) surgery in our clinic between 2008 and 2013 were reviewed retrospectively , and 10 eyes of 8 patients who were diagnosed with dacryocystocele were included in the study .
the median follow - up time for those patients was 22 months ( range 13 to 38 months ) .
the study was conducted in accordance with the tenets of the declaration of helsinki by obtaining written consent from all patients , with the approval of the local ethical review board .
complete ophthalmologic examinations , nose examinations , and ct imaging were done preoperatively for all cases .
those patients who had epiphora complaints , who were observed with a palpable mass at the medial chantal region and no pus coming out from the lower and upper punctum when the mass was pressed with a finger , and who showed a soft ending when a lavage cannula was placed into the punctum were diagnosed with dacryocystocele .
culture specimens were collected from the surgically excised lacrimal sac walls and fluid samples were collected perioperatively for microbiological analysis . the material was also smeared onto sterile labeled glass slides for 10% potassium hydroxide
wet mount , gram stain , giemsa stain , ziehl - neelsen acid fast stain , and kinyoun 's acid fast stain .
specimens were inoculated into sheep 's blood agar , chocolate agar , sabouraud 's dextrose agar , brain heart infusion broth , and thioglycollate medium . at the stage of preparation of preoperative lacrimal sac flaps ,
incisional biopsy samples were collected from the lacrimal sac for histopathological assessment to establish a differential diagnosis .
, an obstruction was experienced in the common canaliculus and it was noted that the obstruction was overcome with a click sound while inserting the intubation tube .
routine external dcr operations were completed and control examinations were made on postoperative day 1 , week 1 , and month 1 and month 3 , month 6 , and then yearly .
anatomic success was assessed by diagnostic probing with a hard stop and irrigation through the passage in all adult patients .
the records of 412 patients who underwent external dcr surgery due to acquired nasolacrimal duct obstruction were reviewed retrospectively .
a total of 10 eyes of 8 patients ( 4 females and 4 males , aged 29 to 75 , mean 52 16.1 years ) with dacryocystoceles were included in this study .
the most common initial symptoms and findings were epiphora ( 100% ) and palpable mass ( 100% ) in the medial canthal area ( figures 1(a ) and 1(b ) ) . in the histories of the patients ,
it was observed that there was the history of a mass in the lacrimal sac region unaccompanied by inflammation in 7 eyes ( 70% ) and dacryocystitis history in 3 eyes ( 30% ) which had been treated in accordance with the diagnosis of acute dacryocystitis . in the initial examination
there was no acute dacryocystitis , trauma history , or any local or systemic disorder which could result in damage in the lacrimal system . in nose examinations ,
computerized tomography imaging demonstrated the fluid collection separated from adjacent tissues by a thin rim corresponding to a dacryocystocele in the sac , but no further lesions ( figures 3(a ) and 3(b ) ) . in the histopathological evaluation of the sample collected from the lacrimal sac wall during surgery
, chronic inflammation findings were observed in all eyes ( 100% ) as well as fibrosis in 2 eyes ( 20% ) ( figure 2 ) .
again , in the microbiological examination of the fluid samples collected from within the cyst during surgery , no bacteria growth in 5 eyes ( 50% ) , gram negative bacillus in 3 eyes ( 30% ) , and gram positive cocci in 2 eyes ( 20% ) were observed ( table 1 ) .
all cases were treated with external dcr combined with bicanalicular silicone tube placement , and no complications were observed , at least at annual follow - ups .
an acquired dacryocystocele is a rare , benign , and painless mass located at the side of the lacrimal sac .
dacryocystoceles usually occur congenitally or less frequently as a result of chronic inflammation , surgeries , and tumors which originate from medial canthal region or sinuses , radiation therapy , or as a side effect of chemotherapeutic drugs .
previously published literature about dacryocystoceles is mostly related to the congenital form . in congenital cases
particularly , dacryocystocele occurrence has been explained as the obstruction of the common canaliculi and lacrimal sac junction , by enlargement of the sac fundus which limits the movement of the rosenmuller valve indirectly , and obstruction of the distal duct by the presence of a persistent membrane between the lacrimal duct and nasal mucosal epithelium , which is present in many newborns [ 35 ] . in patients who develop dacryocystitis following nasolacrimal duct obstruction ( nldo ) , infective materials that accumulate in the sac may enlarge the sac in a form similar to congenital dacryocystocele .
reasons such as the limitation of the movement of the valve , damage to the valve epithelium due to an infective environment , and chronic inflammation may lead to irreversible synechia in the common canaliculus . in our study , a history of dacryocystitis was detected in 3 eyes ( 30% ) , whereas there was no history of dacryocystitis in 7 eyes ( 70% ) ; therefore , these cases were assessed as idiopathic dacryocystocele .
then , one comes to the question as to why the common canaliculus does not get blocked after every chronic dacryocystitis , or in other words , why dacryocystocele does not develop in all chronic dacryocystitis cases . taking this question as the starting point
, we strived to understand the histopathological causes for patients who develop dacryocystocele after nldo , by collecting preoperative microbiological samples and perioperative biopsy samples from the lacrimal sac .
histologically evaluated dacryocystoceles and detected chronic inflammation from the cystic wall of the patients ' samples , whereas woo and kim , in their series of 4 cases , identified partial necrotic changes in addition to chronic inflammation . in our study , we collected specimens from all patients with dacryocystoceles perioperatively , and only the cultures of 5 eyes reproduced bacteria .
further , as the bacteria strains produced were different from each other , we concluded that the formation of dacryocystoceles is not associated with a specific pathogenic agent .
perry et al . reported that prevotella ( gram ( ) bacillus ) and peptostreptococcus ( an aerobic gram ( + ) coccus ) grew in the microbiological analysis of specimens from the dacryocystomucopyocele fluid , which are members of the normal otolaryngeal flora .
reported two familial cases one of which was determined as bilateral dacryocystoceles and the other as unilateral dacryocystoceles .
woo and kim reported bilateral dacryocystoceles in one out of the four cases which was a congenital case associated with punctual agenesis .
we observed bilateral dacryocystoceles in two cases none of which was associated with punctual or canalicular agenesis .
studied the imaging characteristics of dacryocystoceles that occurred after surgery for sinonasal cancers and reported that ct and mr imaging revealed characteristic findings such as a cystic , fluid filled structure with thin rim enhancement and no solid components . in accordance with these findings , we performed ct imaging in all cases in our study , which demonstrated fluid collection separated from adjacent tissues by a thin rim corresponding to a dacryocystocele in the medial canthal area but no other pathologic lesions .
the treatment of dacryocystoceles includes conservative management and drainage followed by external or endoscopic dcr , combined with or without silicone tube placement or dacryocystectomy [ 710 ] . in the previous literature
, it seems that mostly conservative management was preferred in congenital cases and dacryocystectomy was reserved for patients with dry eyes or those who were poor surgical candidates .
we preferred external dcr with silicone tube placement and found that it is a well tolerated and effective method that yields satisfactory results .
particularly when there is no upper lacrimal system absence , such as punctual or canalicular agenesis , external or endoscopic dcr can be the first choice of surgical technique .
if there is an upper lachrymal system damage , then conjunctival dcr may be the first choice . in conclusion
, dacryocystocele should be taken into consideration in the diagnosis of any painless cystic mass in the lacrimal sac area , and ct imaging can be helpful for diagnosis , whereas surgical interventions combining silicon tube placement may give successful results .
we found that although it is not possible to obtain a definite pathogenic agent in all cases of microbiological analysis of dacryocystocele specimens , dacryocystoceles may occur due to chronic dacryocystitis .
it may also develop idiopathically or due to autoimmune fibrous diseases , sinusitis and sinus mucoceles , trauma or osseous configuration in the dysplastic duct wall , from tumors , and secondarily to dacryocystorhinostomy .
previous studies about adult dacryocystoceles are mostly case reports or case series . to our knowledge , however , this study is one of the largest series ; therefore we think that adult dacryocystoceles are more common than expressed through published literature .
further studies on adult dacryocystoceles with larger sample sizes are required to determine the pathologic mechanism and the gold standard treatment modalities .
Output:
| purpose .
the aim of this study is to investigate the etiology and the clinical , microbiological , histopathological , and radiological findings of acquired dacryocystoceles . methods . in this retrospective study
, we reviewed the clinical records of 10 eyes of 8 patients with dacryocystoceles who underwent external dacryocystorhinostomy ( dcr ) surgery .
etiology , presenting symptoms and radiological findings as well as microbiological and histopathological assessment results and outcome were analyzed . results .
the records of 8 patients with dacryocystoceles were included in this study . in the histopathological evaluations of the samples collected from the lacrimal sac wall ,
chronic inflammation was found in all biopsied samples and fibrosis was observed in two histopathological evaluations .
computerized tomography ( ct ) imaging showed fluid collection separated from adjacent tissues by a thin rim , corresponding to dacryocystoceles in the sac . in the microbiological culture examination of samples collected from the fluid within the cyst , no bacterial growth in 5 eyes , gram - negative bacillus growth in 3 eyes , and gram - positive cocci growth in 2 eyes
were found . conclusions .
acquired dacryocystoceles were observed extremely rarely and a definite pathogenic agent could not be identified in any of the cases , either microbiologically or histologically , whereas chronic inflammation was detected in all cases in our study . |
PubmedSumm6533 | ***TASK***
the task is to summarize an input biomedical literature in six sentences
***INPUT***
the input is a biomedical literature
***OUTPUT***
the output is the summary of an input biomedical literature in six sentences
***DOCUMENTATION***
***EXAMPLES***
Input: this disorder may cause by frequent and prolonged contact of the skin with the urine , stool and moisture , and exacerbated by candidiasis infection and abrasion .
signs and symptoms of this disorder may include erythema , flaking , papules and lesions in the areas such as buttocks , thighs , scrotum , and mons pubis .
this disorder commonly occurs in the age of 9 - 12 months old , and its prevalence have reported to be around 7 - 35 and even 50% . the prevalence of diaper dermatitis among the infants is reported to be 75% in the united states ( us ) , 87% in japan , 15% in italy , and 34.9% in iran .
the onset of this disorder commonly occurs within the first 3 to 12 weeks of life , but its peak is in the first 7 to 12 weeks .
the routine treatment options for diaper dermatitis includes changing the diaper and washing the genital area frequently , applying vaseline or zinc oxide , and corticosteroids .
furthermore , a topical antifungal agent ( such as miconazole , clotrimazole , and nystatin ) may be used if fungal infections occurred .
calendula is a plant with the yellow color , which is used to cure skin disorders and pain .
bentonite is basically a kind of mineral , which is in the form of aluminum phyllosilicates with al2o34sio2 h2o formula .
this material can absorb several folds of water as its own volume , and makes a jellified , plastic , and viscose form .
medical powder of bentonite is so fine , odorless , with the color of white to grey , or yellow or pink .
studies have shown that bentonite was effective on the treatment of chronic dermatitis of the hands .
likely , it may be effective on the treatment of skin disorders and diaper dermatitis , but no published studies are found in this regard . on the other hand , in local observations , the researchers observed that parents traditionally apply this mineral to decrease redness , severity , and extent of affected area by diaper dermatitis .
as regard to the observed positive effects , no side - effects and cost - effectiveness of bentonite , and the high prevalence of diaper dermatitis among infants and children which leads to frequent refers to pediatricians and increased stress and anxiety among families , the present study was conducted to compare the effects of bentonite and calendula on the improvement of infantile diaper dermatitis .
the present study was a double - blinded randomized controlled trial which was conducted during february and march 2013 on 60 outpatient infants referred to health care centers or pediatric clinics in khomein city .
all patients were visited by a general practitioner or a pediatrician and diagnosed with diaper dermatitis .
inclusion criteria were : age range of 1 - 24 months , and having mild ( redness , abrasion , and skin atrophy ) to medium ( redness with papules , abrasion , and skin atrophy ) diaper dermatitis .
furthermore , not having infantile eczema , diarrhea , and urinary tract infection , not having fungus dermatitis , and not using corticosteroids for present lesions were selected as additional inclusion criteria .
exclusion criteria were using corticosteroids during study ( even once ) , not following the program during the period , exacerbation of the lesions , and developing diarrhea during the study . to keep the study blind form the physician and the mothers , calendula and bentonite were prepared in cans with similar color , shape and weight and then all cans were coded by the pharmacist as a or b. the treating physician and also the mothers were not aware of cods .
before the sampling started , a randomization plan was developed using the spss ( spss inc . , chicago , il , usa ) software .
for this purpose , we entered numbers 1 - 60 in the data sheet of the software that represented a sample of 60 subjects .
then , using the random numbers option in the compute and function group box in the transform menu we randomly assigned 60 supposed samples into the two conditions , each condition was representative of one group with 30 samples .
the numbers in each group were then sorted and passed to the doctor and he prescribed the medication with code a for one group and medication with code
b to the second group . to begin the study , the researcher talked to the parents , explained the study process , took their agreement ( by taking the written informed consent ) , and then took an initial skin test on the infant 's arm to ensure not having allergic reaction .
to do so , the researcher applied one fingertip of bentonite and calendula on the internal surface of the infant 's arm ( 1 cm 1 cm ) . if redness or any other allergic reactions were not observed after 20 min , the researcher gave bentonite or calendula to them . using a random number table ,
the samples were assigned randomly in bentonite group or in the calendula group ( if redness or any other allergic reactions were not observed ) . a consort flow diagram of this study was as described in figure 1 .
to produce bentonite 50% , the mineral was squashed and turned into powder , sterilized an oven , mixed with water ( 50 g bentonite was mixed with 50 ml of distilled water ) and poured in sterile cans and prepared in the form of bentonite 50% cream in 30 g cans by a pharmacist . to produce calendula , two 15 g creams of calendula 1.5% ( produced by dineh company )
calendula and bentonite were prepared in cans with similar shape and weight and then all cans were coded by the pharmacist . to gather the data ,
a checklist was prepared through literature review and then its content validity was assessed by 10 faculty members in kashan and arak universities of medical sciences .
the reliability of the checklist was assessed through inter - observers reliability . to do this ,
the checklist was completed by the second researcher and a coresearcher ( who was trained formerly ) , for 10 patients ( 2 times with a short break between them ) and a rate of agreement of 0.93 was calculated between them .
the checklist was included the characteristics of the infants ( age , gender , and weight ) , and mother ( education level , age , and job ) , type of feeding ( breast feeding , formula milk , cow 's milk , or combined ) history of diaper dermatitis , and its severity , drugs used in the previous episodes of the disease and the frequency of changing diaper in a day .
there also was a table for recording the effects of treatment including : onset of recovery in the first 6 h ( yes , no ) , improvement in the 1 , 2 , and 3 day ( yes / no ) , time of the complete recovery ( 1 , 2 , 3 , and more days after the start of treatment ) .
checklists were completed by the second researcher for each infant and then the physician ( who was unaware of the cans cods ) visited the baby and prescribed one of the two creams according to the random plan previously prepared .
a can contained one of the drugs was given to the mother of each infant , and they were told that additional drugs will be prescribed in the next visit if necessary .
all mothers were taught to apply the cream on the affected area 4 times a day after changing the diaper .
the second researcher educated both groups of parents about the following items and wanted them to do the 1 time at her presence for ensuring both the researcher and the mothers of the correct care :
to wash the affected area only with lukewarm water and dry it with a clean cotton towel.to spread the prescribed cream on the affected area as it covers 1 cm over the lesions borders , then diaper the baby , and repeat this work every 4 - 6 h. if needed , they could repeat this work more times.not to apply any other material on the affected area such as wet wipes , essence contained soaps , or other medications .
to wash the affected area only with lukewarm water and
dry it with a clean cotton towel . to spread the prescribed cream on the affected area as it covers 1 cm over the lesions borders , then diaper the baby , and repeat this work
every 4 - 6 h. if needed , they could repeat this work more times . not to apply any other material on the affected area such as wet wipes ,
the second researcher followed the process of administrating the cream , following the treatment program and the effect of treatment 3 times a day by phone .
also , every other day ( up to 3 times ) , the infants were visited and assessed both by the researcher and the physician and additional cream of the same code was given to the parents if needed .
the effect of treatment ( improvement or nonimprovement ) was documented based on the physician 's decision .
the study was approved by the institutional review board and the human research ethics committee in the kashan university of medical sciences ( project number : 91121 ) .
in addition , parents of all babies were informed about the design of the study and assured about data confidentiality , safeness of the study , and their right not to participate .
the parents were also assured that the baby will be under the close and frequent observation of the research team for any possible side - effect or the delay in recovery .
we also observed all ethical issues in accordance with the last version of the declaration of helsinki .
independent sample t - test was used to compare quantitative variables ( i.e. , age , weight ) , and chi - square and fisher 's exact test were used to compare qualitative variables between two groups such as improvement .
the mean ( standard error ) age of infants was 5.68 0.84 months in calendula group and 6.88 1.02 months in bentonite group ( p = 0.42 ) .
in calendula group , 10 samples were males ( 33.3% ) and 20 were female ( 66.7% ) , and in bentonite group nine samples were males ( 30% ) and 21 were female ( 70% ) ; however , no significant difference was observed between the two groups ( p = 0.78 ) [ table 1 ] .
basic characteristics of the infants and their mothers in total , 93.3% of lesions in the infants in bentonite group started its recovery in the first 6 h while this rate was 40% in calendula group , and the higher rate of improvement in the bentonite group was significant ( p < 0.001 ) [ table 2 ] .
the start of improvement in the first 6 h and complete improvement in the first 3 days furthermore , 90% of infants in the bentonite group and 36.7% in the calendula group were improved completely in the first 3 days . this higher rate of improvement in bentonite group was significant ( p < 0.001 ) [ table 2 ] .
findings of the present study showed that the onset of improvement in the first 6 h was significantly higher in bentonite group than in calendula group . also , the complete improvement in the first 3 days was significantly higher in bentonite group .
emami - razavi et al . , in a study on animal samples made 2 cm lesions on the mature rats skins and reported that bentonite was effective on the improvement of these lesions . in another study ,
fowler assessed the effectiveness of bentonite on the improvement of chronic dermatitis of the hands on human samples and reported that using the moisturizer cream containing bentonite in an 8 weeks period , significantly accelerated the improvement of chronic dermatitis . despite searching the scientific databases ,
no studies about the effectiveness of bentonite on the improvement of diaper dermatitis were found .
some studies have assessed the effects of some herbal products on the improvement of diaper dermatitis .
one study has assessed the effects of a cream containing honey , olive oil and beeswax , and another study has assessed the effects of olive oil in diaper dermatitis and reported relatively positive effects .
fotouhi et al . , in a study aimed to compare the effects of calendula and betamethasone in the prevention of acute radiation dermatitis reported that calendula and betamethasone had the same effects in the palliation of the disease severity . in the present study ,
the rate of improvement in bentonite group was greater than the mentioned studies . in a study ,
panahi et al . , compared the effects of aloe vera and calendula on children younger than 3 years old with diaper dermatitis and reported that calendula was more effective than a. vera in a 10 day period .
, showed the effectiveness of calendula on the improvement of diaper dermatitis ; however , the present study showed that bentonite was not only more effective than calendula on the improvement of diaper dermatitis , but it accelerated the speed of improvement , too .
in the present study , the effects of calendula and bentonite were compared on the improvement of diaper dermatitis .
findings showed that bentonite was effective on the improvement of diaper dermatitis , and also bentonite had faster effects compare to calendula .
these advantages may be related to anti - inflammatory , antibacterial , water absorbing and skin protecting properties of this traditional product .
it is also important to note that no side - effects were observed in the two groups .
however , the study sample in the present study was small , and it is recommended to conduct similar studies with a larger sample .
furthermore , the present study was conducted on the samples with mild to moderate diaper dermatitis , so it is recommended to conduct multicenter studies on severe diaper dermatitis .
Output:
| background : diaper dermatitis is one of the most common skin disorders of infancy and childhood . the present study aimed to compare the effects of bentonite and calendula on the improvement of diaper dermatitis in infants.materials and methods : a double - blind randomized controlled trial , which was conducted on 60 out - patient infants referred to health care centers or pediatric clinics in khomein city and diagnosed with diaper dermatitis .
data were collected by checklist and observation , and analyzed using t - test , chi - square , and fisher 's exact test.results:mean ( standard error ) age of the total sample was 6.55 0.69 months . totally ,
93.3% of lesions in the bentonite group started its recovery in the first 6 h , while this rate was 40% in calendula group ( p < 0.001 ) . furthermore , 90% of infants in the bentonite group and 36.7% in the calendula group were improved completely in the first 3 days ( p < 0.001).conclusion : bentonite was effective on the improvement of diaper dermatitis , and also had faster effects compared with calendula . |
PubmedSumm6534 | ***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: immunometabolism is an emerging field of investigation including immunology and biochemical pathways that govern metabolism
. accelerating interest in this area is being fuelled by increased lifespan and the relatively recent knowledge that aging affects the immune system and promotes inflammation that is associated with metabolic dysfunctions .
ageing is associated with an increase in visceral obesity in men and women , which has been claimed as the prominent cause of systemic metabolic perturbations and chronic inflammation . in particular , with ageing , vat expands and becomes hypovascularized and resident adipocytes quickly release proinflammatory cytokines as response to such stressful condition [ 35 ] . among the produced proinflammatory molecules , tumour necrosis factor ( tnf ) and interleukin 6 ( il-6 ) have been most intensively studied for their involvement in inducing systemic metabolic perturbations .
polyphenols are the most promising natural compounds to combat metabolic syndromes including age - related inflammatory states .
many polyphenols are efficient antioxidants and anti - inflammatory molecules by virtue of their ability to directly scavenge inflammation - derived radicals , to increase antioxidants expression , and to block inflammatory cytokines production by modulating the activity of specific transcription factors . in adipose tissue
, the polyphenol resveratrol ( rsv ) suppresses both systemic and adipose tissue inflammation and has the potential to improve age - associated metabolic disorders and to increase insulin sensitivity [ 7 , 8 ] .
moreover , rsv inhibits triglycerides accumulation by suppressing adipocytes differentiation and by stimulating lipid catabolism via the induction of the adipose triglyceride lipase ( atgl ) .
it has been firstly identified in white adipose tissue and represents the rate - limiting enzyme of triglycerides lipolysis . moreover ,
fatty acids ( fas ) liberated by atgl have been implicated in lipid signalling mediated by the family of peroxisome proliferator activated receptors ( ppars ) .
ppars are ligand - activated nuclear receptors , which can be activated by fas and have been mainly studied in the transcriptional regulation of genes involved in glucose and lipid metabolism .
atgl - mediated fa / ppar signalling was demonstrated to be essential to maintain mitochondrial oxidative metabolism and in vat orchestrates stress resistance adaptation of adipocytes to limited nutrient delivery , thus counteracting cell death and the onset of the inflammatory response .
atgl activity changes during aging , and it has been suggested that its expression levels are directly related to the inflammatory status [ 5 , 14 , 15 ] .
more precisely , atgl downregulation is described in several age - related metabolic disorders ( i.e. , insulin resistance - related states ) characterized by an increased level of inflammatory mediators [ 16 , 17 ] .
importantly , ppars , including ppar , play a very important role in the regulation of inflammatory responses .
however , even though cell metabolism and inflammation are known to be tightly regulated by lipid signalling , the mechanism by which atgl modulates the production of inflammatory mediators is unclear . in particular , whether fa / ppar is involved in the anti - inflammatory effect of atgl has not been fully addressed yet . in the present work we have investigated whether atgl has a role in orchestrating pro - inflammatory cytokines production in aged adipocytes and whether the anti - inflammatory activity of rsv is associated with modulation of atgl .
we housed and sacrificed all mice in accordance with accepted standard of humane animal care and with the approval by relevant national ( ministry of welfare ) and local ( institutional animal care and use committee , tor vergata university ) committees .
c57bl/6 male mice were purchased from harlan laboratories srl ( urbino , italy ) . for the experiments , 1- , 7- , 14- , and
mice were killed by cervical dislocation ; vat was explanted immediately , frozen on dry ice , and stored at 80c .
3t3-l1 murine preadipocytes and c2c12 murine myoblasts were purchased from american type cell culture ( atcc ) and grown in dmem supplemented with 10% newborn serum or 10% fetal bovine serum and 1% pen / strep mix ( lonza sales , basel , switzerland ) . 3t3-l1 and
c2c12 cells were seeded at density of 2 10 cells per well in 6-well plates and differentiated in adipocytes and myotubes , respectively , as previously reported [ 9 , 19 ] .
louis , mo , usa ) was solubilized in dmso and added at concentration of 100 m for up to 48 h , a condition that was demonstrated to be effective in selectively inducing atgl expression in adipocytes .
atgl and scramble sirnas ( santa cruz biotechnology , dallas , texas , usa ) were transfected by using the deliverx plus kit ( affymetrix , santa clara , ca , usa ) as previously described .
3 g of rna was used for retrotranscription with m - mlv ( promega , madison , wi , usa ) .
qpcr was performed in triplicates by using validated qpcr primers ( blast ) , ex taq qpcr premix ( lonza sales ) , and the real time pcr lightcycler ii ( roche diagnostics , indianapolis , in , usa ) .
mrna levels were normalized to -actin mrna , and the relative mrna levels were determined by using the 2 method .
cells and vat were lysed in ripa buffer ( 50 mm tris hcl ph 8.0 , 150 mm nacl , 0.1% sds , 0.5% sodium deoxycholate , and 1% np-40 ) supplemented with protease inhibitors cocktail ( merck millipore , darmstadt , germany ) .
western blotting analysis was performed as previously described by using the following polyclonal antibodies : atgl , -actin , gapdh , i , tnf ( santa cruz biotechnologies ) , and phosphoactive forms of nf ( pnfb ) ( cell signalling technologies , danvers , ma , usa ) .
statistical evaluation was conducted by anova , followed by the post - student - newman - keuls .
during aging vat expands and undergoes hypovascularization concomitantly with immunometabolic perturbations [ 3 , 5 ] .
in particular , vat peaks at middle age or early old age and then declines substantially in advanced old age [ 24 , 25 ] .
the inflammatory state that commonly accompanies aging , also called inflammaging , has been proposed to be causative of a systemic metabolic perturbation .
vat has been proposed at the nexus of the mechanisms and pathways involved in the genesis of age - related inflammatory disorders .
atgl upregulation represents a stress adaptive response of adipocytes to hypovascularization that is crucial to buffer energetic catastrophe and to prevent cell death and tissue inflammation .
the present study was designed to investigate whether the dramatic inflammatory picture typically observed during late ageing could be triggered by the failure of the atgl - mediated adaptive response . as showed in figure 1(a ) , and in line with what we previously reported , vat of 7- and 14-month - old mice displayed higher levels of atgl protein with respect to 1-month - old mice . however ,
a decline of atgl was observed at later stage of ageing ( figure 1(a ) ) . in particular , the oldest mice ( 24-months - old )
had atgl protein level comparable to that of 1-month - old mice ( figure 1(a ) , bottom panel ) .
moreover , rt - qpcr analysis demonstrated a significant reduction of atgl mrna in the oldest mice with respect to young ones , suggesting an impaired atgl expression ( figure 1(b ) ) .
we then attempted to reveal the degree of inflammation in vat of the oldest mice with respect to the youngest and we found a stronger production of il-6 mrna .
notwithstanding , we did not reveal any changes in macrophages marker cd-14 ( figure 1(c ) ) , suggesting that the production of inflammatory cytokines was independent of cellular - mediated immune response .
this data is supported by our previous evidence showing that macrophages were not infiltrated in vat of old mice . to confirm the ability of adipose cells residing in vat of 24-month - old mice to produce inflammatory cytokines independently of cell immunity
, we have set up an in vitro aging model of adipocytes by culturing differentiated 3t3-l1 adipocytes for 21 days and compared the mrna levels of atgl , tnf , and il-6 to those of 3t3-l1 adipocytes after 8 days of differentiation . as shown in figure 2(a ) , we detected reduced mrna level of atgl and its downstream target ppar. this event was associated with an upregulation of tnf and il-6 expression in 21-day - old adipocytes compared with the 8-day - old adipocytes , thus nicely recapitulating the in vivo results obtained with 24-month - old mice ( figure 1(b ) ) .
therefore , on the basis of these data we can postulate that the failure of atgl - mediated stress response observed in 24-month - old and 21-day - old adipocytes triggers the production of proinflammatory cytokines . in agreement with this idea , higher levels of inflammatory markers
the modulatory action of atgl on tissue inflammation has been reported recently also in cardiac muscle . in particular , a prominent upregulation of different inflammatory markers ( e.g. , tnf and il-6 ) was observed in steatotic hearts of atgl ko mice .
thus , we asked whether downregulation of atgl in cultured skeletal muscle myotubes could result in enhanced inflammation markers as well . to this end , we downregulated atgl in fully differentiated c2c12 myotubes [ atgl( ) ] through rnai .
coherently , atgl( ) myotubes displayed decreased ppar and a greater mrna expression level of tnf than controls ( figure 2(b ) ) .
fas are liberated by atgl function as lipid signalling molecules leading to activation of ppar , which favours the expression of lipid oxidative genes .
an impaired fa / ppar signalling was observed during atgl deficiency in vat and adipocytes and this may initiate sequelae of events that eventually lead to the induction of proinflammatory genes . in support of this assumption ppar ko mice show a prolonged inflammatory response .
the involved mechanism is that ppar is a strong repressor of nfb transcription factor and of its downstream inflammatory cytokines in different cell types including adipocytes .
moreover , ppar is able to inhibit inflammation in several pathological conditions including hepatic steatosis and obesity [ 2931 ] .
the anti - inflammatory role of ppar in our system is strongly supported by the analysis of ppar mrna in 21-day - old adipocytes and in vat of the 24-month - old mice , which evidenced a significant reduction of ppar concomitant with production of inflammatory mediators .
several studies have suggested that the health benefits of rsv are mediated by its antioxidant capacity . in the context of adipocytes physiology
, rsv strongly inhibits adipogenesis by inducing the synthesis of the main nonenzymatic intracellular antioxidant , that is , glutathione . in doing so
, rsv buffers the onset of a prooxidant milieu , which is mandatory for adipocytes differentiation . other findings support rsv efficacy also in reducing the inflammatory response in several tissues such as brain during neurodegenerative processes and adipose tissue upon high fat and sugar diet .
the main anti - inflammatory mechanism of rsv seems to be related to the inhibitory action of nfb - mediated pathways including the transcription of tnf and il-6 . according to lasa et al .
, we found that treatment of 8-day - old adipocytes with rsv efficiently impinged upon a strong atgl protein accumulation at 24 h , which was accompanied by the decrease of phosphoactive nfb ( figure 2(c ) ) . to dissect whether atgl / fa / ppar axis
could be involved in the anti - inflammaging action of rsv , we analysed the level of atgl and ppar after rsv administration in 21-day - old adipocytes .
we found a significant upregulation of both atgl and ppar expression ( figure 2(a ) ) .
coherently , a simultaneous decrease of tnf and il-6 mrna expression was observed after rsv treatment ( figure 2(a ) ) .
as reported in the literature , stress stimuli such as lps or nutrient starvation upregulate atgl [ 5 , 37 ] . moreover , atgl ko mice challenged with lps display enhanced inflammation in liver compared to wt and show increased mortality and torpor , and these events have been attributed to impaired ppar activity .
next , given that rsv has an anti - inflammaging action and this nicely correlates with the upregulation of atgl and ppar , we asked whether rsv could also restrain the increase of tnf and il-6 caused by atgl downregulation through rnai , in 8-day - old adipocytes .
as reported in figure 3(a ) , atgl lacking cells [ atgl( ) ] displayed impaired ppar expression and higher expression of tnf and il-6 than controls , in line with what we observed in c2c12 myotubes ( figure 2(b ) ) and previously revealed on primary adipocytes and mouse embryonic fibroblasts .
however , contrary to what we observed in 21-day - old adipocytes , rsv was unable to revert the induction of tnf and il-6 in atgl( ) adipocytes ; but rather it unexpectedly further upregulated their mrna expression , indicating an enhancement of nfb activity ( figure 3(a ) ) . to confirm the proinflammatory role of rsv in atgl( ) adipocytes , we carried out an immunoblotting analysis of the transcriptional phosphoactive form of nfb ( pnfb ) and its inhibitory partner ib .
figure 3(b ) shows an increased pnfb level in atgl( ) adipocytes treated with rsv that was paralleled by the decrease of ib ( figure 3(b ) ) .
rsv has been proposed as a plausible gerosuppressant natural compound to overcome age - related metabolic perturbations and chronic inflammatory states [ 8 , 38 , 39 ] .
interestingly , in rhesus monkeys , rsv administration reduces nfb activation in high fat diet fed animals , suppressing inflammation in vat with beneficial action on metabolic profile . our data point out that , in condition of irreversible atgl inhibition ( silenced atgl expression ) , rsv would not function as anti - inflammatory agent , the atgl - mediated fa / ppar signalling axis being strongly affected .
thus , we can speculate that the anti - inflammatory potential of rsv is strongly dependent on atgl / fa / ppar pathway ( figure 4 ) .
overall these findings further support the anti - inflammatory role of atgl in adipocytes and suggest that rsv , being a powerful enhancer of atgl expression / activity , is able to reinforce the anti - inflammatory fa / ppar signalling [ 5 , 15 ] .
given that rsv is ineffective in inhibiting nfb when atgl is lacking , we can suggest that this lipase also efficiently modulates nfb activity by ( i ) restraining its phosphorylation and ( ii ) stabilizing the inhibitory partner ib .
these hypotheses remain to be elucidated yet and are currently under investigation in our laboratory .
importantly , recent papers demonstrate that rsv worsens the clinical symptoms in mice models of multiple sclerosis , exacerbating inflammation and neuronal demyelization .
moreover , rsv has been found to activate nfb and to increase inflammatory cytokines in cardiac cells .
these findings and our data collectively indicate that caution should be exercised in using rsv against inflammatory states .
here we give additional effort to the authentic role of atgl as a stress responsive protein , having the capacity to suppress the production of age - related proinflammatory cytokines in adipocytes .
atgl being an important node in the promotion of lipid signalling , the anti - inflammaging effect of atgl seems to proceed via the induction of fa / ppar-mediated pathway in that ppar functions as a valid suppressor of inflammatory cytokines at the level of gene transcription .
importantly , we have also pointed out that rsv can act as a powerful anti - inflammatory agent thanks to its ability to restore atgl expression , which is hardly compromised by ageing , thus allowing fa / ppar signalling to proceed towards the repression of cytokines production .
therefore , on the basis of our findings we can state that rsv could act as a powerful enhancer of atgl / fa / ppar pathway , thus representing a valid natural tool to limit the onset and/or the exacerbation of the age - related metabolic disorders and inflammatory states .
Output:
| ageing is characterized by the expansion and the decreased vascularization of visceral adipose tissue ( vat ) , disruption of metabolic activities , and decline of the function of the immune system , leading to chronic inflammatory states .
we previously demonstrated that , in vat of mice at early state of ageing , adipocytes mount a stress resistance response consisting in the upregulation of atgl , which is functional in restraining the production of inflammatory cytokines . here , we found that , in the late phase of ageing , such an adaptive response is impaired .
in particular , 24-months - old mice and aged 3t3-l1 adipocytes display affected expression of atgl and its downstream ppar-mediated lipid signalling pathway , leading to upregulation of tnf and il-6 production . we show that the natural polyphenol compound resveratrol ( rsv ) efficiently suppresses the expression of tnf and il-6 in an atgl / ppar dependent manner .
actually , adipocytes downregulating atgl do not show a restored ppar expression and display elevated cytokines production .
overall the results obtained highlight a crucial function of atgl in inhibiting age - related inflammation and reinforce the idea that rsv could represent a valid natural compound to limit the onset and/or the exacerbation of the age - related inflammatory states . |
PubmedSumm6535 | ***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: remodeling after tooth extraction results in substantial horizontal ( 3 - 4 mm ) and vertical ( 1 - 2 mm ) alveolar bone loss [ 13 ] .
this postextraction alveolar bone loss can compromise or prevent subsequent implant placement , while loss of crestal support compromises the position and appearance of the soft tissues in aesthetic areas . in an effort to minimize postextraction alveolar bone remodeling and thus prevent its undesirable sequelae , alveolar ridge preservation ( arp , a form of guided bone regeneration , gbr ) was developed as a therapeutic modality .
several studies have been conducted to evaluate the effectiveness of different arp surgical techniques ( e.g. , flapped versus flapless and primary intention healing versus no primary closure ) and materials ( e.g. , occlusive membranes and bone grafts ) , and several approaches have proven successful to varying degrees [ 116 ] .
systematic reviews indicate that the combination of bone grafts with resorbable membranes achieved the best results [ 13 ] . however , a high incidence of membrane exposure ( potentially leading to infection ) , early membrane degradation with inadequate barrier function , postoperative discomfort with coronal flap movement , and loss of width and thickness of keratinized tissue in the alveolar ridge are among the reported complications [ 2 , 6 , 8 , 17 ] .
soft tissue management is important for maintaining an appropriate soft tissue profile for future tooth- or implant - supported restorations [ 1821 ] .
for example , in patients with thin biotype , a connective tissue graft may be recommended during or after arp . in this context , a resorbable barrier that preserves soft tissue attributes could be a valuable addition to arp protocols .
recently , a new xenogeneic collagen matrix ( xcm ) ( mucograft , geistlich pharma ag , wolhusen , switzerland ) of porcine origin has been introduced into clinical practice that is made of non - cross - linked collagen types i and iii .
the new xcm is designed with a bilayer structure to support tissue ingrowth , regeneration , and integration within the host tissue .
it has been specifically designed for soft tissue regeneration and has been histologically and clinically evaluated for root coverage and keratinized tissue augmentation .
studies report complete integration and revascularization with mature mucosal and submucosal tissues after 3 months , in both nonsubmerged and submerged healing environments [ 2233 ] .
the structural characteristics of this xcm and the studies indicating that it maintains its barrier function for at least 30 days suggest that it could also be used as a gbr device [ 22 , 23 , 28 ] . results of clinical studies suggesting that the width and thickness of keratinized tissue can be maintained or increased , even if this matrix is left exposed , indicate that this xcm may be used without coronal advancement of flaps or periosteal - releasing incisions [ 27 , 29 ] .
these are potentially significant advantages since such an approach could minimize the reported complications following gbr .
the aim of this case series is to report clinical , radiographic , and histological outcomes following use of a new xcm in combination with freeze - dried bone allograft ( fdba ) for arp .
nine nonsmoking patients ( aged 2174 years ; 2 males and 7 females ) were treated with arp after extraction of 18 teeth in a private practice in athens , greece , from october 2010 to october 2012 .
all patients had a noncontributory medical history and required arp either prior to future implant placement or for preservation of aesthetics prior to fabrication of a maxillary anterior tooth - supported fixed restoration ( table 1 ) .
a presurgical evaluation , consisting of a detailed oral and periodontal examination and full mouth radiographic assessment , was conducted on all patients .
three patients presented with gingivitis , 4 presented with moderate or severe periodontitis , and 2 were on maintenance .
all patients received at least one session of oral hygiene instruction and scaling prior to tooth extraction , in order to establish an oral environment more favorable to wound healing .
in addition , periodontal treatment comprising of root planing under local anesthesia and access / regenerative surgery , when necessary , was completed prior to the arp procedure .
the recommended treatment was thoroughly explained to each patient and written informed consent was obtained .
all patients received antibiotics ( amoxicillin 500 mg three times a day for 8 days or azithromycin 250 mg once a day for 6 days ) starting 2 days preoperatively . following minimal flap elevation with soft tissue preservation , atraumatic extractions were performed , using piezosurgical instruments ( piezotome , satelec acteon , merignac , france ) .
buccal bone wall defects were present in all sockets , with a buccal bony dehiscence extending > 50% of the length of the socket in seven sites .
the fdba ( cortical bone ( 2501000 m ) lifenet , virginia beach , va , usa ) was rehydrated and used to completely fill the sockets and resulting bony defects .
the xcm was trimmed and adapted to cover the defects and 2 - 3 mm of the adjacent bone .
the flaps were repositioned ( no periosteal release was performed ) and sutured with nonabsorbable monofilament sutures ( gore - tex , w. l. gore & associates , flagstaff , az , usa ) ( figures 1 , 2 , 3 , and 6 ) .
postoperatively , patients were given instructions and prescriptions for antimicrobial rinse ( chlorhexidine gluconate 0.12% ) two times a day for 3 weeks and analgesics ( acetaminophen 1000 mg or ibuprofen 400 mg ) as needed for pain .
patients were seen at 1 , 2 , 4 , 8 , 12 , and 24 weeks postoperatively .
radiographic examination included periapical radiographs preoperatively and 6 months postoperatively and cone - beam computed tomography ( cbct ) scans in 6 patients at 6 months .
histological and immunohistochemical analysis included 9 sites from 4 patients 6 months after arp ( table 1 ) . following thorough discussion and explanation of the procedure , patients agreed to proceed , and an informed consent form was signed that was based on the helsinki declaration of 1975 , as revised in 2000 .
soft tissues , approximately 3 4 mm in size , removed by soft tissue punches during guided implant placement surgery ( navigator system , biomet 3i , palm beach gardens , fl , usa ) or ridge modification for construction of ovate pontics , were not discarded but placed in 10% buffered formalin , processed , and stored for future analysis .
after fixation in 10% buffered formalin , 5 m thick paraffin - embedded tissue sections were stained with hematoxylin and eosin .
streptavidin - biotin - peroxidase immunohistochemistry was performed with a fully automated slide preparation system ( ventana benchmark xt , ventana medical systems inc . ,
tucson , az , usa ) and commercially available detection kit ( iview dab , ventana medical systems inc .
antibodies used were pan - keratin ( dilution 1 : 50 ) ( clone ae1/ae3 , dako , carpinteria , ca , usa ) and cd34 ( dilution 1 : 50 ) ( clone qbend 10 , dako , carpinteria , ca , usa ) .
appropriate positive and negative ( i.e. , primary antibodies substituted with nonimmune serum ) controls were used according to manufacturers ' instructions .
postoperatively , patients reported only minor swelling and discomfort or pain ; in all cases , healing was uneventful .
the exposed matrix portions remained intact during the first 8 postoperative weeks and were slowly replaced by mature keratinized tissue within 2 - 3 months .
the clinical appearance of the soft tissue between postoperative visits at 8 weeks and 24 weeks suggested that the width and thickness had increased ( figures 4 and 5 ) .
radiographic assessment on cbct scans at 24 weeks indicated adequate crestal bone width for standard - size implant placement in all sites , which was confirmed during surgery ( figures 4 , 6 , 7 , and 8) .
horizontal ridge width , measured with specialized software ( simplant , materialise dental nv , belgium ) 1 mm below the most coronal aspect of the crest perpendicular to the long axis of the ridge , ranged from 5.8 to 7.6 mm .
all treatment - planned implants were placed in acceptable positions and all fixed restorations fulfilled the aesthetic demands of the case without need for further soft or hard tissue augmentation procedures ( figure 5 ) ( table 1 ) .
following processing of the gross specimens ( figure 9(a ) ) , microscopic examination showed that all specimens consisted of normal - appearing oral mucosa , covered by parakeratinized squamous epithelium with long interconnecting rete pegs ( figure 9(b ) ) .
the lamina propria was composed of fibrous connective tissue with interlacing bands of collagen fibers , showing many fibroblasts and medium- and small - sized vessels ( figure 9(c ) ) .
the full thickness of the regenerated epithelium reacted with the pan - keratin antibody ( figure 9(d ) ) , while many capillary vessels lined by cd34-positive endothelial cells were regularly distributed in the lamina propria ( figures 9(e ) and 9(f ) ) .
this case series reports on the clinical , radiographic , and histological outcomes after use of a new xcm and fdba when performing arp following tooth extraction .
the treatment plan called for the treated sites to subsequently receive either dental implant placement or tooth - supported fixed partial dentures .
the clinical and radiographic results indicated that the xcm - fdba combination resulted in successful arp outcomes , with minimal complications or patient discomfort and pain .
the xcm remained clinically intact during the first 8 postoperative weeks ; this suggests that the barrier function was maintained during the first 2 months of healing .
clinically , the exposed matrix portions were slowly replaced by mature keratinized tissue within 2 - 3 months , with tissue width and thickness seemingly increasing between the postoperative visits at 8 weeks and 24 weeks .
all implants were placed in acceptable positions without need for further soft or hard tissue augmentation procedures , thus minimizing possible additional discomfort and cost for the patient during placement .
the histological and immunohistochemical results indicated that the soft tissue regenerated over the extraction sites has the characteristics of normal keratinized oral mucosa .
these findings are consistent with some of the recent clinical [ 27 , 2931 ] and histological studies [ 24 , 27 ] suggesting that the width and thickness of keratinized tissue can be maintained or even increased when this specific matrix is left exposed .
the reported complete integration and formation of mature mucosal and submucosal tissues suggested that the new xcm could also be used as a gbr device [ 22 , 23 , 28 ] and that the xcm - fdba combination could be an additional valuable option when performing arp for subsequent implant placement or fixed partial denture restorative treatment .
however , the limitations of this study small and heterogeneous clinical , radiographic , and histological sample size ; lack of clinical and preoperative radiographic measurements ; and one time point of histological assessment suggest caution in interpreting the results .
randomized controlled clinical trials are necessary to confirm the efficacy and predictability of this approach and to assess the long - term outcomes of implant therapy or conventional prosthodontics in sites treated with this protocol . for a successful outcome in maintaining barrier function during the early postoperative healing period
, resorbable barrier membranes used in gbr must possess certain properties , including biocompatibility , preferential tissue integration , place - holder characteristics , and adequate physicochemical stability .
collagen - based materials have often been explored for gbr applications because of the desirable material properties of collagen ( natural origin , rapid biodegradation rate , biocompatibility , etc . ) .
however , these same characteristics may prove to be a disadvantage , since barrier function may be limited over time . to decrease the degradation rate and enhance the temporal stability of collagen - based membranes , manufacturers have used several cross - linking approaches .
although cross - linking may address membrane stability in the oral or wound environment , it may also result in compromised attachment and proliferation of desirable connective tissue wound cells ( e.g. , fibroblasts ) , which could lead to delayed wound healing and possible infection as well as to undesirable tissue reaction .
one such technique involves the combination of non - cross - linked native collagen iii , which undergoes relatively fast degradation , and collagen i , which is more resistant , in order to tightly control membrane degradation .
in addition , the literature shows that intentional exposure of such bioresorbable membranes does not jeopardize the procedure outcomes ( alveolar bone and keratinized tissue preservation ) [ 2 , 37 ] .
the new non - cross - linked xcm is composed of collagen type i and type iii without further cross - linking or chemical treatment .
the xcm matrix is a bilayer : one side is thin and smooth and is of low porosity , while the other is a more porous 3-dimensional network .
the xcm must be placed with the thin and smooth surface as the external layer since it is designed to allow cell attachment and host tissue integration but at the same time to remain impermeable to invading cells for 30 days .
the more porous part is designed to be the internal layer since it is rapidly infiltrated by host mesenchymal cells [ 22 , 23 ] .
in summary , the favorable preliminary results reported here indicate that the xcm used could be a valuable alternative for arp procedures .
randomized controlled clinical trials are necessary to confirm its efficacy and predictability and to assess the long - term outcomes of implant therapy or conventional prosthodontics in sites treated with this protocol .
Output:
| alveolar ridge preservation ( arp ) has been shown to prevent postextraction bone loss .
the aim of this report is to highlight the clinical , radiographic , and histological outcomes following use of a bilayer xenogeneic collagen matrix ( xcm ) in combination with freeze - dried bone allograft ( fdba ) for arp .
nine patients were treated after extraction of 18 teeth . following minimal flap elevation and atraumatic extraction ,
sockets were filled with fdba .
the xcm was adapted to cover the defect and 2 - 3 mm of adjacent bone and flaps were repositioned .
healing was uneventful in all cases , the xcm remained in place , and any matrix exposure was devoid of further complications . exposed matrix portions were slowly vascularized and replaced by mature keratinized tissue within 2 - 3 months .
radiographic and clinical assessment indicated adequate volume of bone for implant placement , with all planned implants placed in acceptable positions . when fixed partial dentures were placed , restorations fulfilled aesthetic demands without requiring further augmentation procedures .
histological and immunohistochemical analysis from 9 sites ( 4 patients ) indicated normal mucosa with complete incorporation of the matrix and absence of inflammatory response .
the xcm + fdba combination resulted in minimal complications and desirable soft and hard tissue therapeutic outcomes , suggesting the feasibility of this approach for arp . |
PubmedSumm6536 | ***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: renal cell carcinoma ( rcc ) is representative kidney cancer and has increased annually in the recent 2 decades .
although surgery remains the standard curative treatment for rcc , approximately 30% of patients with rcc develop metastatic disease after surgery , and approximately one third of patients with rcc have metastasis at the time of diagnosis .
several prognostic parameters have been evaluated and grade , histologic subtype , and stage remain important prognostic parameters in localized rcc . in addition , some preoperative parameters , including platelet count , c - reactive protein ( crp ) , and erythrocyte sedimentation rate have been considered for their prognostic relevance .
thrombocytosis ( tc ) , particularly secondary type has been regarded as a poor prognostic factor in many malignant diseases including gastric , gynecologic , and lung cancer .
recent studies have demonstrated an association of lower survival after operation with reactive tc for variable type of cancer , platelet count could have relation with the systemic inflammatory response , even though the exact relation between inflammation , platelet , and cancer outcomes is still not known .
the purpose of this study is to examine the association of preoperative tc with the prognosis of nonmetastatic rcc patients .
this study was approved by the ethics committee of yeungnam university school of medicine and informed consents were waived because the operations were done between 1997 and 2009 . in this
study the medical records of 187 patients who underwent radical nephrectomy for nonmetastatic rcc between july 1997 and june 2009 were reviewed retrospectively .
all patients were examined by routine hematologic laboratories and radiologic imaging including chest x - ray and abdominal computed tomography .
the definition of tc was platelet count400,000 l , and patients were divided into 2 groups by presence of preoperative tc .
tumor stage was reassigned using the 2002 tnm classification of the american joint committee on cancer ( ajcc ) .
postoperatively , every 3 or 6 month , all patients were evaluated for the first 2 years and every 6 months for next 2 years , and annually thereafter .
preoperative variabels including sex , gender , platelet count , neutrophil to lymphocytes ratio ( nlr ) , platelet to lymphocyte ratio ( plr ) , tumor size , tumor grade , histology and t stage were recorded .
moreover , distant metastasis during follow - up periods was also represented as a variable .
fisher exact test and chi - square test were used for comparison of discrete variables between the 2 groups .
receiver operating characteristics ( roc ) curves were generated to determine cutoff points for nlr and plr .
the overall survival ( os ) and cancer - specific survival ( css ) were estimated using the kaplan - meier survival analysis and the log - rank test .
univariate and multivariable analysis was fulfilled using the cox proportional hazard model and logistic regression for assessment of significant parameters associated with survival .
in this study the medical records of 187 patients who underwent radical nephrectomy for nonmetastatic rcc between july 1997 and june 2009 were reviewed retrospectively .
all patients were examined by routine hematologic laboratories and radiologic imaging including chest x - ray and abdominal computed tomography .
the definition of tc was platelet count400,000 l , and patients were divided into 2 groups by presence of preoperative tc .
tumor stage was reassigned using the 2002 tnm classification of the american joint committee on cancer ( ajcc ) .
postoperatively , every 3 or 6 month , all patients were evaluated for the first 2 years and every 6 months for next 2 years , and annually thereafter .
preoperative variabels including sex , gender , platelet count , neutrophil to lymphocytes ratio ( nlr ) , platelet to lymphocyte ratio ( plr ) , tumor size , tumor grade , histology and t stage were recorded .
moreover , distant metastasis during follow - up periods was also represented as a variable .
fisher exact test and chi - square test were used for comparison of discrete variables between the 2 groups . receiver
operating characteristics ( roc ) curves were generated to determine cutoff points for nlr and plr .
the overall survival ( os ) and cancer - specific survival ( css ) were estimated using the kaplan - meier survival analysis and the log - rank test .
univariate and multivariable analysis was fulfilled using the cox proportional hazard model and logistic regression for assessment of significant parameters associated with survival .
the mean follow - up period was 59.342.1 months and patients ' mean age was 56.011.7 years . mean tumor size was 5.22.9 cm .
twenty patients ( 10.7% ) had t3 or t4 tumors , and 20 patients ( 10.7% ) had preoperative tc .
thirty patients ( 16.0% ) developed metastasis and 9 patients ( 4.8% ) died during follow - up period .
the cutoff value of nlr was 1.81 ( area under the curve [ auc]=0.547 ; sensitivity , 0.5 ; specificity , 0.51 ) and plr was 128.7 ( auc=0.703 ; sensitivity , 0.67 ; specificity , 0.51 ) in the roc curve ( table 1 ) .
preoperative tc showed significant correlation with t stage ( p=0.028 ) , and metastasis ( p=0.001 ) , nlr1.81 ( p=0.003 ) , plr128.7 ( p=0.001 ) , but not with age , tumor histology subtype , gender , grade or tumor size ( table 2 ) . in kaplan - meier analysis using univariate log - rank test , css rate ( p=0.013 ) and os rate ( p=0.012 ) showed significant association with preoperative tc ( fig .
1 ) . tc , t stage , tumor size , and distant metastasis were significantly influencing parameters for css in both univariate and multivariable analysis . controlling for pathological tnm stage , tumor size and fuhrman grade , cox proportional hazards model for css rates showed that preoperative tc was an independent prognostic factor ( p=0.025 ) ( table 3 ) .
cox proportional hazards model for os rates showed that distant metastasis was an independent prognostic factor in multivariable analysis ( p=0.001 ) ( table 4 ) .
the european association of urology guidelines advise use of the tnm classification , fuhrman nuclear grade , and histological subtype for treatment of rcc .
the pathological stage according to tnm classification is the most important prognostic factor in rcc , followed by fuhrman grade .
many recent studies have examined platelet counts and tc as a useful prognostic factor in predicting survival and recurrence of rcc .
tc has also been reported in various malignancies and has been investigated as a prognostic factor .
primary tc is due to clonal tc and occurs in chronic myelodysplastic or myeloproliferative disorders .
secondary tc has been studied in many malignancies , including liver , gastrointestinal tract , lung , cervix , and others .
several theories have been suggested on how tc may be related to worse survival and the metastatic potential in malignancy .
one theory , tc in rcc patients may increase tumorigenesis by increasing platelet - derived growth factor , which is a mitogen for various cell types . according to another theory
in addition , platelets may provide for the adherence , penetration , and sequestration of malignant cells through the endothelial wall .
many cytokines including interleukin-6 or interleukin-11 , stem cell factor , granulocyte - macrophage colony - stimulating factor , and thrombopoietin are assumed to contribute to tc .
tc has been investigated as a valuable prognostic factor in predicting survival and recurrence in rcc patients . in their retrospective study of 1,422 patients who underwent radical or partial nephrectomy for rcc , either localized or metastatic , wosnitzer et al .
however , when excluding metastatic patients , tc was not an independent predictor of os and css .
a different result was reported by brookman - may et al . in their study of 3,139 patients who underwent surgery for rcc at four centers ,
preoperative tc was an independent predictor for decreased css in localized rcc patients and tc had no independent influence on css in metastatic disease . in a review of the records of 204 patients with rcc who underwent radical nephrectomy , o'keefe et al
. reported that the overall and cancer specific death rate in 26 patients with tc was 50% and 42% .
however , in the remaining the normal platelet counts 178 patients , the same variables were 15.2% and 7.3% . in their study the cancer - specific death rate was 5 times greater in patients with tc .
they concluded that tc was a potent independent prognostic factor in patients with localized rcc .
cho et al . , who studied the association of tc and preoperative crp elevation with prognosis of nonmetastatic rcc patients in korea , found that crp and tc were significant prognostic factors associated with recurrence - free survival in univariate analysis , whereas multivariate analysis showed that tc was not an independent prognostic factor but crp was . in the current study , significantly lower os and css was observed in the tc group and tc , t stage , tumor size , and distant metastasis were significantly influencing parameters for css in both univariate and multivariable analysis . controlling for other parameters ,
reported that preoperative tc is a significant prognostic factor in localized rcc patients and tc was more frequent in advanced stage rcc patients , and patients with preoperative tc had worse survival compared to patients with normal platelet counts .
nlr is recently , one of the most investigated inflammation prognostic markers of postoperative outcome .
in fact , as it has relation with inflammatory response , the role in identifying patients with high - risk has been suggested in noncancer and cancer patients .
different studies have emphasized the role of high for detection of poorer prognosis cancer patients , in terms of both overall and cancer disease - free survival and general comorbidities .
plr was identified as a prognostic marker in advanced gastric cancer patients treated with chemotherapy , however mainly the studies are retrospective and pertain to only a few kinds of cancer . in our study ,
( p=0.003 ) , plr1.28.7 ( p=0.001 ) , but nlr and plr were not significant influencing factors for css in both univariate and multivariable analysis .
limitations of this study include the retrospective data assessment and no information was available concerning performance status , symptoms at the time of diagnosis , and further hematologic laboratory parameters such as crp or hematocrit , and platelet count was assessed only before the operation .
furthermore , only the influence of tc on os and css was evaluated , but not on recurrence - free survival , which can also be of interest .
based on the results of the current study preoperative tc is a significant predictor for determining prognosis in nonmetastatic rcc patients and patients with preoperative tc had worse survival compared to patients with normal platelet counts .
thus , preoperative platelet count may be clinically useful for risk stratifying patients undergoing surgery for nonmetastatic rcc .
Output:
| purposethe aim of this study was to examine the association of preoperative thrombocytosis with the prognosis of patients with nonmetastatic renal cell carcinoma ( rcc).materials and methodswe conducted a retrospective analysis of 187 patients who underwent a radical nephrectomy for nonmetastatic rcc between july 1997 and june 2009 .
thrombocytosis was defined as a platelet count400,000 l , and patients were divided into 2 groups according to presence of preoperative thrombocytosis , and the cancer - specific survival rates and overall survival rates of the 2 groups after radical nephrectomy were compared.resultsthe mean age of the patients was 56.011.7 years and the mean follow - up period was 59.342.1 months ; there were 20 patients with preoperative thrombocytosis .
thirty patients developed metastases and 9 patients died during the follow - up period . in kaplan - meier analysis using a univariate log - rank test ,
both cancer - specific survival rate ( p=0.013 ) and overall survival rate ( p=0.012 ) showed significant association with preoperative thrombocytosis .
controlling for pathological tnm stage , fuhrman grade and tumor diameter , the cox proportional hazards model for cancer - specific survival rates showed that preoperative thrombocytosis was an independent prognostic factor ( p=0.025).conclusionspreoperative thrombocytosis was associated with poorer prognosis in patients with nonmetastatic rcc .
thus , preoperative platelet count may be clinically useful for risk stratification of patients undergoing surgery for nonmetastatic rcc . |
PubmedSumm6537 | ***TASK***
the task is to summarize an input biomedical literature in six sentences
***INPUT***
the input is a biomedical literature
***OUTPUT***
the output is the summary of an input biomedical literature in six sentences
***DOCUMENTATION***
***EXAMPLES***
Input: recent technical developments have improved the versatility , applicability and quantitative nature of em , leading to a revival of ultrastructural analysis .
advances include 3d em , large scale 2d em and improved methods and reagents for correlated light microscopy and electron microscopy ( clem ) to compare other modes of microscopic analysis directly to the em level .
large - scale 2d em is particularly suitable to quantify or identify ( novel ) disease features for human pathology , study animal models for disease and tissue culture models . due to the typically small field of view
it is difficult to correlate changes at high magnification to a tissue wide scale , as well as to unbiasedly and quantitatively analyze ultrastructural features . for pathological analysis of human tissue or the assessment of pathology in animal models , haematoxylin and eosin ( h&e ) colored sections of formaldehyde fixed paraffin
embedded ( ffpe ) tissue is the standard . besides simple h&e staining immunolabeling is also performed to identify pathological abnormalities .
if such tissues could be analyzed at the em level , specific cell types , and subcellular changes could be identified .
the unbiased nature of large scale em allows finding unexpected and novel features of disease . by large - scale em areas up to
we and others previously applied nanotomy to rat pancreatic islets , cell culture , rat brain , skin and mucosa and whole zebrafish larvae ( www.nanotomy.org ) .
zebrafish are highly suitable for in vivo imaging , in particularly to visualize cell types which are difficult to access in mammalian tissues including brain immune cells . here
the nanotomy procedure is described in detail , applied to coronal sections of zebrafish heads undergoing conditional neuronal ablation by conversion of metronidazole by neuronal expressed nitroreductase ( www.nanotomy.org ) .
all raw data is presented as zoomable html files , visualizing molecular to tissue scale changes .
the presentation of the raw data allows unbiased analyses of the datasets from other angles by experts worldwide .
all experiments with zebrafish larvae were approved by the animal experimentation committee of the university of groningen according to national and eu guidelines .
fixation and embedding
fixation
anaesthetize fish larvae in tricaine ( 0.003% ) added to the e3 ( 5 mm nacl , 0.17 mm kcl , 0.33 mm cacl2 , 0.33 mm mgso4 , 10 mm hepes , ph 7.6 ) zebrafish water and test for depth of anesthesia by poking gently with a 200 l pipette tip under dissection microscope until motion is no longer detected ( figure 1a).when processing samples for correlative em after acquiring in vivo imaging data using confocal or 2 photon imaging in 1.8% agarose as described , fix larvae in agarose using 4% pfa in pbs containing triton - x-100 ( 0.05%).cut larvae from agarose and process for large - scale em.fix larvae in fresh 4% paraformaldehyde in pbs containing triton - x-100 ( 0.05% ) for 2 hr at room temperature in plastic tubes .
note : cells grown in culture ( in vitro ) can be directly fixed in glutaraldehyde , as described in the next step ( 1.1.1.5).remove solution and add 100 l 0.5% pfa , 2% glutaraldehyde ( ga ) , and 0.1 m sodium cacodylate ( ph 7.4 ) . store overnight at 4 c .
rinse samples twice in 0.1 m sodium cacodylate.cut larval heads rostrally to the hindbrain to facilitate penetration of osmium .
use fine syringes / forceps.postfix larvae in 1% osmium tetroxide ( oso4)/1.5% potassium ferrocyanide ( k4[fe(cn)6 ] ) in 0.1 m sodium cacodylate on ice for 2 hr and rinse 3 x 5 min in double distilled h2o.dehydrate in ethanol by 20 min incubations in increasing ethanol concentrations ( 50% , 70% , 3 times 100% ) .
embedding
prepare epoxy resin according to standard recipes used in em labs . note : we use epoxy resin as follows : mix 19.8 g glycid ether 100 , 9.6 g 2-dodecenylsuccinic acid anhydride and 11.4 g methylnadic anhydride using a magnetic stirrer . add 0.5 g dmp-30 ( tris-(dimethylaminomethyl ) phenol ) and mix again.incubate larvae overnight in 50% epoxy resin in ethanol ( v / v ) while rotating ( rt).replace diluted epoxy - resin with pure resin .
incubate for 30 min , add fresh resin again and incubate for another 30 min .
again refresh the resin and then incubate 3 hr at rt , followed by 15 min at 58 c and another 1 hr at rt under low pressure ( 200 mbar).orient the heads in commercially available silicon flat embedding molds under a dissection microscope using a needle or toothpick with the anterior facing the side of the mold or as needed(figure 1b).polymerize epoxy resin overnight at 58 c .
if epoxy resin is still too soft allow another day to polymerize and harden at 58 c .
if this easily leaves an indentation allow another day to polymerize and harden at 58 c .
when specimen is fully hardened proceed to trimming and sectioning.trim away excess resin from the stub using razor blades ( figure 1b ) .
fixation
anaesthetize fish larvae in tricaine ( 0.003% ) added to the e3 ( 5 mm nacl , 0.17 mm kcl , 0.33 mm cacl2 , 0.33 mm mgso4 , 10 mm hepes , ph 7.6 ) zebrafish water and test for depth of anesthesia by poking gently with a 200 l pipette tip under dissection microscope until motion is no longer detected ( figure 1a).when processing samples for correlative em after acquiring in vivo imaging data using confocal or 2 photon imaging in 1.8% agarose as described , fix larvae in agarose using 4% pfa in pbs containing triton - x-100 ( 0.05%).cut larvae from agarose and process for large - scale em.fix larvae in fresh 4% paraformaldehyde in pbs containing triton - x-100 ( 0.05% ) for 2 hr at room temperature in plastic tubes .
note : cells grown in culture ( in vitro ) can be directly fixed in glutaraldehyde , as described in the next step ( 1.1.1.5).remove solution and add 100 l 0.5% pfa , 2% glutaraldehyde ( ga ) , and 0.1 m sodium cacodylate ( ph 7.4 ) . store overnight at 4 c .
rinse samples twice in 0.1 m sodium cacodylate.cut larval heads rostrally to the hindbrain to facilitate penetration of osmium .
use fine syringes / forceps.postfix larvae in 1% osmium tetroxide ( oso4)/1.5% potassium ferrocyanide ( k4[fe(cn)6 ] ) in 0.1 m sodium cacodylate on ice for 2 hr and rinse 3 x 5 min in double distilled h2o.dehydrate in ethanol by 20 min incubations in increasing ethanol concentrations ( 50% , 70% , 3 times 100% ) .
anaesthetize fish larvae in tricaine ( 0.003% ) added to the e3 ( 5 mm nacl , 0.17 mm kcl , 0.33 mm cacl2 , 0.33 mm mgso4 , 10 mm hepes , ph 7.6 ) zebrafish water and test for depth of anesthesia by poking gently with a 200 l pipette tip under dissection microscope until motion is no longer detected ( figure 1a ) . when processing samples for correlative em after acquiring in vivo imaging data using confocal or 2 photon imaging in 1.8% agarose as described , fix larvae in agarose using 4% pfa in pbs containing triton - x-100 ( 0.05% )
fix larvae in fresh 4% paraformaldehyde in pbs containing triton - x-100 ( 0.05% ) for 2 hr at room temperature in plastic tubes .
note : cells grown in culture ( in vitro ) can be directly fixed in glutaraldehyde , as described in the next step ( 1.1.1.5 ) . remove solution and add 100 l 0.5% pfa , 2% glutaraldehyde ( ga ) , and 0.1 m sodium cacodylate ( ph 7.4 ) . store overnight at 4 c .
postfix larvae in 1% osmium tetroxide ( oso4)/1.5% potassium ferrocyanide ( k4[fe(cn)6 ] ) in 0.1 m sodium cacodylate on ice for 2 hr and rinse 3 x 5 min in double distilled h2o .
dehydrate in ethanol by 20 min incubations in increasing ethanol concentrations ( 50% , 70% , 3 times 100% ) .
note : we use epoxy resin as follows : mix 19.8 g glycid ether 100 , 9.6 g 2-dodecenylsuccinic acid anhydride and 11.4 g methylnadic anhydride using a magnetic stirrer .
add 0.5 g dmp-30 ( tris-(dimethylaminomethyl ) phenol ) and mix again.incubate larvae overnight in 50% epoxy resin in ethanol ( v / v ) while rotating ( rt).replace diluted epoxy - resin with pure resin .
incubate for 30 min , add fresh resin again and incubate for another 30 min .
again refresh the resin and then incubate 3 hr at rt , followed by 15 min at 58 c and another 1 hr at rt under low pressure ( 200 mbar).orient the heads in commercially available silicon flat embedding molds under a dissection microscope using a needle or toothpick with the anterior facing the side of the mold or as needed(figure 1b).polymerize epoxy resin overnight at 58 c .
if epoxy resin is still too soft allow another day to polymerize and harden at 58 c .
if this easily leaves an indentation allow another day to polymerize and harden at 58 c .
when specimen is fully hardened proceed to trimming and sectioning.trim away excess resin from the stub using razor blades ( figure 1b ) .
note : we use epoxy resin as follows : mix 19.8 g glycid ether 100 , 9.6 g 2-dodecenylsuccinic acid anhydride and 11.4 g methylnadic anhydride using a magnetic stirrer .
incubate larvae overnight in 50% epoxy resin in ethanol ( v / v ) while rotating ( rt ) .
incubate for 30 min , add fresh resin again and incubate for another 30 min .
again refresh the resin and then incubate 3 hr at rt , followed by 15 min at 58 c and another 1 hr at rt under low pressure ( 200 mbar ) .
orient the heads in commercially available silicon flat embedding molds under a dissection microscope using a needle or toothpick with the anterior facing the side of the mold or as needed(figure 1b ) .
if epoxy resin is still too soft allow another day to polymerize and harden at 58 c .
if this easily leaves an indentation allow another day to polymerize and harden at 58 c .
trim away excess resin from the stub using razor blades ( figure 1b ) .
sectioning , contrasting , and mounting
sectioning
section epoxy resin block using an ultramicrotome.use a glass knife or a diamond histoknife to cut semithin sections ( 500 nm ) for toluidine blue / basic fuchsin ( figure 1d ) staining to detect the right positioning.transfer semi - thin sections on microscopic slides by picking them up with a glass pasteur pipet whose tip has been closed by melting in a flame .
stain for 10 sec with 1% toluidine blue in water on a hot plate and after rinsing with water , stain for 10 sec with 0.05% basic fuchsin in 1% sodium tetraborate .
examine with a normal light microscope at 10x to 40x.when the proper site / orientation within the brain is reached , continue sectioning the epoxy resin block with a diamond knife to cut ultrathin sections ( ~ 70 nm ; figure 1e)use easily identifiable anatomic structures in and around the brain , including olfactory pits , eyes , grey - white matter boundaries , to identify the region of interest during ultrathin sectioning and to adjust the sectioning angle when the sample is tilted.mount section on single slot l2 x 1 copper grids ( figure 1f ) , to allow acquisition uninterrupted by grid bars .
contrasting
stain ultrathin sections on grids for 2 min in 2% uranyl acetate in methanol followed by reynolds lead citrate for another 2 min .
sectioning
section epoxy resin block using an ultramicrotome.use a glass knife or a diamond histoknife to cut semithin sections ( 500 nm ) for toluidine blue / basic fuchsin ( figure 1d ) staining to detect the right positioning.transfer semi - thin sections on microscopic slides by picking them up with a glass pasteur pipet whose tip has been closed by melting in a flame .
stain for 10 sec with 1% toluidine blue in water on a hot plate and after rinsing with water , stain for 10 sec with 0.05% basic fuchsin in 1% sodium tetraborate .
examine with a normal light microscope at 10x to 40x.when the proper site / orientation within the brain is reached , continue sectioning the epoxy resin block with a diamond knife to cut ultrathin sections ( ~ 70 nm ; figure 1e)use easily identifiable anatomic structures in and around the brain , including olfactory pits , eyes , grey - white matter boundaries , to identify the region of interest during ultrathin sectioning and to adjust the sectioning angle when the sample is tilted.mount section on single slot l2 x 1 copper grids ( figure 1f ) , to allow acquisition uninterrupted by grid bars .
use a glass knife or a diamond histoknife to cut semithin sections ( 500 nm ) for toluidine blue / basic fuchsin ( figure 1d ) staining to detect the right positioning .
transfer semi - thin sections on microscopic slides by picking them up with a glass pasteur pipet whose tip has been closed by melting in a flame .
stain for 10 sec with 1% toluidine blue in water on a hot plate and after rinsing with water , stain for 10 sec with 0.05% basic fuchsin in 1% sodium tetraborate .
when the proper site / orientation within the brain is reached , continue sectioning the epoxy resin block with a diamond knife to cut ultrathin sections ( ~ 70 nm ; figure 1e ) use easily identifiable anatomic structures in and around the brain , including olfactory pits , eyes , grey - white matter boundaries , to identify the region of interest during ultrathin sectioning and to adjust the sectioning angle when the sample is tilted . mount section on single slot l2 x 1 copper grids ( figure 1f ) , to allow acquisition uninterrupted by grid bars .
contrasting
stain ultrathin sections on grids for 2 min in 2% uranyl acetate in methanol followed by reynolds lead citrate for another 2 min .
stain ultrathin sections on grids for 2 min in 2% uranyl acetate in methanol followed by reynolds lead citrate for another 2 min .
large scale stem note : we use scanning em with an external scan generator capable of acquiring multiple large fields of view at high resolution using stem detection .
typically , one image generated this way is equivalent to the fields of view of ~ 100 transmission electron microscope ( tem ) images , significantly reducing the amount of stitching .
mounting sample in microscopeplace grid with section in the multiple grid sample holder and transfer into the chamber of the sem.alignment of the stem detectorput the grid with the sample under the beam and move it up so it will be approx .
acquire an image at 20 kv using the in - lens detector.focus on grid edge and adjust working distance to 4.0 mm.move the sample holder to a safe position and bring in the stem detector.center the hole of the stem detector in the image - field by turning the adjustments screws while imaging at maximum speed with the in - lens detector.carefully bring back the sample holder which will just fit between the lens pole and the detector.acquire an image with the in - lens detector to be sure to be on the section area.switch to stem detection ( gain medium and all quadrants set on ' minus ' ) and acquire an image and select the area to be scanned.raise acceleration voltage to 21 kv and wait for stabilization of the beam ( stable image again ) and then go to 29 kv in steps of 2 kv.acquiring imagespre - irradiate the sample ( to prevent brightness changes caused by the e - beam ) by zooming out so the complete area to be scanned fits the image window.change aperture to 120 m ( to keep the proper dynamic range the detector gains have to be reduced one step).de - focus so the image is blurred.make the scanned area as tight as possible using the reduced area scan option.set scan speed such that a frame is scanned in approx . 1 - 2 sec .
note : depending on the size and tissue this typically takes hr ( 100 x 100 m fov ) to up to 3 hr ( 1,000 x 500 m).zoom in at least 100x and scan a small area for 10 sec .
note : when this area does not change brightness compared to its surrounding , pre - irradiation is sufficient.bring back the 30 m aperture ( and stem gain on medium)focus the sample.align aperture using the wobbler ( at ~ 40,000x magnification).while in focus select the lightest area / feature , set scan speed such that details are visible.in the microscope software adjust brightness and contrast by carefully watching the histogram to keep all pixels in the dynamic range .
do the same for the darkest area / features.go back to the bright area and check again .
be on the safe side so there is some space on both sides of the histogram.zoom out so the complete area to be scanned fits the imaging window , and start the large area acquisition program.use the wizard option to set up a mosaic by selecting an area from the screen .
use dwell time 3 s for stem.select option " autofocus on previous tile " , use the large scale acquisition software autofocus with default company settings , check box " verify setting prior to execution " and define where to save the data.press " optimize " to check microscope settings .
this might be up to 72 hr for 1 x 0.5 mm areas.in window " maximum tile resolution " type 20,000 so individual tiles will not be bigger than 20k x 20k , preventing blunt edge effects .
press " execute".when asked for checking focus and brightness / contrast ( b / c ) , switch off external scan generator and carefully adjust focus and astigmatism in the microscope software . do not change b / c .
note : the stage can be moved and magnification changed , but magnification has to be set back to the desired pixel size.switch on external scan generator again and press " continue " .
mounting sample in microscopeplace grid with section in the multiple grid sample holder and transfer into the chamber of the sem .
place grid with section in the multiple grid sample holder and transfer into the chamber of the sem .
alignment of the stem detectorput the grid with the sample under the beam and move it up so it will be approx .
acquire an image at 20 kv using the in - lens detector.focus on grid edge and adjust working distance to 4.0 mm.move the sample holder to a safe position and bring in the stem detector.center the hole of the stem detector in the image - field by turning the adjustments screws while imaging at maximum speed with the in - lens detector.carefully bring back the sample holder which will just fit between the lens pole and the detector.acquire an image with the in - lens detector to be sure to be on the section area.switch to stem detection ( gain medium and all quadrants set on ' minus ' ) and acquire an image and select the area to be scanned.raise acceleration voltage to 21 kv and wait for stabilization of the beam ( stable image again ) and then go to 29 kv in steps of 2 kv .
put the grid with the sample under the beam and move it up so it will be approx .
center the hole of the stem detector in the image - field by turning the adjustments screws while imaging at maximum speed with the in - lens detector .
carefully bring back the sample holder which will just fit between the lens pole and the detector .
acquire an image with the in - lens detector to be sure to be on the section area . switch to stem detection ( gain medium and all quadrants set on ' minus ' ) and acquire an image and select the area to be scanned .
raise acceleration voltage to 21 kv and wait for stabilization of the beam ( stable image again ) and then go to 29 kv in steps of 2 kv .
acquiring imagespre - irradiate the sample ( to prevent brightness changes caused by the e - beam ) by zooming out so the complete area to be scanned fits the image window.change aperture to 120 m ( to keep the proper dynamic range the detector gains have to be reduced one step).de - focus so the image is blurred.make the scanned area as tight as possible using the reduced area scan option.set scan speed such that a frame is scanned in approx .
1 - 2 sec . note : depending on the size and tissue this typically takes hr ( 100 x 100 m fov ) to up to 3 hr ( 1,000 x 500 m).zoom in at least 100x and scan a small area for 10 sec .
note : when this area does not change brightness compared to its surrounding , pre - irradiation is sufficient.bring back the 30 m aperture ( and stem gain on medium)focus the sample.align aperture using the wobbler ( at ~ 40,000x magnification).while in focus select the lightest area / feature , set scan speed such that details are visible.in the microscope software adjust brightness and contrast by carefully watching the histogram to keep all pixels in the dynamic range .
do the same for the darkest area / features.go back to the bright area and check again .
be on the safe side so there is some space on both sides of the histogram.zoom out so the complete area to be scanned fits the imaging window , and start the large area acquisition program.use the wizard option to set up a mosaic by selecting an area from the screen .
use dwell time 3 s for stem.select option " autofocus on previous tile " , use the large scale acquisition software autofocus with default company settings , check box " verify setting prior to execution " and define where to save the data.press " optimize " to check microscope settings .
this might be up to 72 hr for 1 x 0.5 mm areas.in window " maximum tile resolution " type 20,000 so individual tiles will not be bigger than 20k x 20k , preventing blunt edge effects .
press " execute".when asked for checking focus and brightness / contrast ( b / c ) , switch off external scan generator and carefully adjust focus and astigmatism in the microscope software .
note : the stage can be moved and magnification changed , but magnification has to be set back to the desired pixel size.switch on external scan generator again and press " continue " . pre - irradiate the sample ( to prevent brightness changes caused by the e - beam ) by zooming out so the complete area to be scanned fits the image window .
change aperture to 120 m ( to keep the proper dynamic range the detector gains have to be reduced one step )
make the scanned area as tight as possible using the reduced area scan option . set scan speed such that a frame is scanned in approx
note : depending on the size and tissue this typically takes hr ( 100 x 100 m fov ) to up to 3 hr ( 1,000 x 500 m ) .
note : when this area does not change brightness compared to its surrounding , pre - irradiation is sufficient .
bring back the 30 m aperture ( and stem gain on medium ) align aperture using the wobbler ( at ~ 40,000x magnification ) .
while in focus select the lightest area / feature , set scan speed such that details are visible . in the microscope software adjust brightness and contrast by carefully watching the histogram to keep all pixels in the dynamic range .
be on the safe side so there is some space on both sides of the histogram . zoom out so the complete area to be scanned fits the imaging window , and start the large area acquisition program . use the wizard option to set up a mosaic by selecting an area from the screen .
select option " autofocus on previous tile " , use the large scale acquisition software autofocus with default company settings , check box " verify setting prior to execution " and define where to save the data . press
this might be up to 72 hr for 1 x 0.5 mm areas . in window
" maximum tile resolution " type 20,000 so individual tiles will not be bigger than 20k x 20k , preventing blunt edge effects . press " execute " .
when asked for checking focus and brightness / contrast ( b / c ) , switch off external scan generator and carefully adjust focus and astigmatism in the microscope software .
note : the stage can be moved and magnification changed , but magnification has to be set back to the desired pixel size .
open large - scale em file viewer program and open the file " mosaic info " .
this preferably is performed on another workstation to not obstruct new acquisitions . choose option ' auto stitch entire mosaic ( parameters overlap mode on half , stitching threshold 0.90 , noise reduction automatic . in case stitching criteria can not be fulfilled , zoom in and manually place tile in position and click ' continue as is ' ) .
perform annotations in the tif file by opening it in an image editing program . in parallel , open the zoomable html file in a web browser for optimal resolution observation .
fixation and embedding
fixation
anaesthetize fish larvae in tricaine ( 0.003% ) added to the e3 ( 5 mm nacl , 0.17 mm kcl , 0.33 mm cacl2 , 0.33 mm mgso4 , 10 mm hepes , ph 7.6 ) zebrafish water and test for depth of anesthesia by poking gently with a 200 l pipette tip under dissection microscope until motion is no longer detected ( figure 1a).when processing samples for correlative em after acquiring in vivo imaging data using confocal or 2 photon imaging in 1.8% agarose as described , fix larvae in agarose using 4% pfa in pbs containing triton - x-100 ( 0.05%).cut larvae from agarose and process for large - scale em.fix larvae in fresh 4% paraformaldehyde in pbs containing triton - x-100 ( 0.05% ) for 2 hr at room temperature in plastic tubes .
note : cells grown in culture ( in vitro ) can be directly fixed in glutaraldehyde , as described in the next step ( 1.1.1.5).remove solution and add 100 l 0.5% pfa , 2% glutaraldehyde ( ga ) , and 0.1 m sodium cacodylate ( ph 7.4 ) . store overnight at 4 c .
rinse samples twice in 0.1 m sodium cacodylate.cut larval heads rostrally to the hindbrain to facilitate penetration of osmium .
use fine syringes / forceps.postfix larvae in 1% osmium tetroxide ( oso4)/1.5% potassium ferrocyanide ( k4[fe(cn)6 ] ) in 0.1 m sodium cacodylate on ice for 2 hr and rinse 3 x 5 min in double distilled h2o.dehydrate in ethanol by 20 min incubations in increasing ethanol concentrations ( 50% , 70% , 3 times 100% ) .
note : we use epoxy resin as follows : mix 19.8 g glycid ether 100 , 9.6 g 2-dodecenylsuccinic acid anhydride and 11.4 g methylnadic anhydride using a magnetic stirrer .
add 0.5 g dmp-30 ( tris-(dimethylaminomethyl ) phenol ) and mix again.incubate larvae overnight in 50% epoxy resin in ethanol ( v / v ) while rotating ( rt).replace diluted epoxy - resin with pure resin .
incubate for 30 min , add fresh resin again and incubate for another 30 min .
again refresh the resin and then incubate 3 hr at rt , followed by 15 min at 58 c and another 1 hr at rt under low pressure ( 200 mbar).orient the heads in commercially available silicon flat embedding molds under a dissection microscope using a needle or toothpick with the anterior facing the side of the mold or as needed(figure 1b).polymerize epoxy resin overnight at 58 c .
if epoxy resin is still too soft allow another day to polymerize and harden at 58 c .
if this easily leaves an indentation allow another day to polymerize and harden at 58 c .
when specimen is fully hardened proceed to trimming and sectioning.trim away excess resin from the stub using razor blades ( figure 1b ) .
fixation
anaesthetize fish larvae in tricaine ( 0.003% ) added to the e3 ( 5 mm nacl , 0.17 mm kcl , 0.33 mm cacl2 , 0.33 mm mgso4 , 10 mm hepes , ph 7.6 ) zebrafish water and test for depth of anesthesia by poking gently with a 200 l pipette tip under dissection microscope until motion is no longer detected ( figure 1a).when processing samples for correlative em after acquiring in vivo imaging data using confocal or 2 photon imaging in 1.8% agarose as described , fix larvae in agarose using 4% pfa in pbs containing triton - x-100 ( 0.05%).cut larvae from agarose and process for large - scale em.fix larvae in fresh 4% paraformaldehyde in pbs containing triton - x-100 ( 0.05% ) for 2 hr at room temperature in plastic tubes .
note : cells grown in culture ( in vitro ) can be directly fixed in glutaraldehyde , as described in the next step ( 1.1.1.5).remove solution and add 100 l 0.5% pfa , 2% glutaraldehyde ( ga ) , and 0.1 m sodium cacodylate ( ph 7.4 ) . store overnight at 4 c .
rinse samples twice in 0.1 m sodium cacodylate.cut larval heads rostrally to the hindbrain to facilitate penetration of osmium .
use fine syringes / forceps.postfix larvae in 1% osmium tetroxide ( oso4)/1.5% potassium ferrocyanide ( k4[fe(cn)6 ] ) in 0.1 m sodium cacodylate on ice for 2 hr and rinse 3 x 5 min in double distilled h2o.dehydrate in ethanol by 20 min incubations in increasing ethanol concentrations ( 50% , 70% , 3 times 100% ) .
anaesthetize fish larvae in tricaine ( 0.003% ) added to the e3 ( 5 mm nacl , 0.17 mm kcl , 0.33 mm cacl2 , 0.33 mm mgso4 , 10 mm hepes , ph 7.6 ) zebrafish water and test for depth of anesthesia by poking gently with a 200 l pipette tip under dissection microscope until motion is no longer detected ( figure 1a ) . when processing samples for correlative em after acquiring in vivo imaging data using confocal or 2 photon imaging in 1.8% agarose as described , fix larvae in agarose using 4% pfa in pbs containing triton - x-100 ( 0.05% )
fix larvae in fresh 4% paraformaldehyde in pbs containing triton - x-100 ( 0.05% ) for 2 hr at room temperature in plastic tubes .
note : cells grown in culture ( in vitro ) can be directly fixed in glutaraldehyde , as described in the next step ( 1.1.1.5 ) .
remove solution and add 100 l 0.5% pfa , 2% glutaraldehyde ( ga ) , and 0.1 m sodium cacodylate ( ph 7.4 ) . store overnight at 4 c .
postfix larvae in 1% osmium tetroxide ( oso4)/1.5% potassium ferrocyanide ( k4[fe(cn)6 ] ) in 0.1 m sodium cacodylate on ice for 2 hr and rinse 3 x 5 min in double distilled h2o .
dehydrate in ethanol by 20 min incubations in increasing ethanol concentrations ( 50% , 70% , 3 times 100% ) .
embedding
prepare epoxy resin according to standard recipes used in em labs .
note : we use epoxy resin as follows : mix 19.8 g glycid ether 100 , 9.6 g 2-dodecenylsuccinic acid anhydride and 11.4 g methylnadic anhydride using a magnetic stirrer .
add 0.5 g dmp-30 ( tris-(dimethylaminomethyl ) phenol ) and mix again.incubate larvae overnight in 50% epoxy resin in ethanol ( v / v ) while rotating ( rt).replace diluted epoxy - resin with pure resin .
incubate for 30 min , add fresh resin again and incubate for another 30 min . again
refresh the resin and then incubate 3 hr at rt , followed by 15 min at 58 c and another 1 hr at rt under low pressure ( 200 mbar).orient the heads in commercially available silicon flat embedding molds under a dissection microscope using a needle or toothpick with the anterior facing the side of the mold or as needed(figure 1b).polymerize epoxy resin overnight at 58 c .
if epoxy resin is still too soft allow another day to polymerize and harden at 58 c .
if this easily leaves an indentation allow another day to polymerize and harden at 58 c .
when specimen is fully hardened proceed to trimming and sectioning.trim away excess resin from the stub using razor blades ( figure 1b ) .
note : we use epoxy resin as follows : mix 19.8 g glycid ether 100 , 9.6 g 2-dodecenylsuccinic acid anhydride and 11.4 g methylnadic anhydride using a magnetic stirrer .
incubate larvae overnight in 50% epoxy resin in ethanol ( v / v ) while rotating ( rt ) .
incubate for 30 min , add fresh resin again and incubate for another 30 min .
again refresh the resin and then incubate 3 hr at rt , followed by 15 min at 58 c and another 1 hr at rt under low pressure ( 200 mbar ) .
orient the heads in commercially available silicon flat embedding molds under a dissection microscope using a needle or toothpick with the anterior facing the side of the mold or as needed(figure 1b ) .
if epoxy resin is still too soft allow another day to polymerize and harden at 58 c .
if this easily leaves an indentation allow another day to polymerize and harden at 58 c .
trim away excess resin from the stub using razor blades ( figure 1b ) .
sectioning , contrasting , and mounting
sectioning
section epoxy resin block using an ultramicrotome.use a glass knife or a diamond histoknife to cut semithin sections ( 500 nm ) for toluidine blue / basic fuchsin ( figure 1d ) staining to detect the right positioning.transfer semi - thin sections on microscopic slides by picking them up with a glass pasteur pipet whose tip has been closed by melting in a flame .
stain for 10 sec with 1% toluidine blue in water on a hot plate and after rinsing with water , stain for 10 sec with 0.05% basic fuchsin in 1% sodium tetraborate .
examine with a normal light microscope at 10x to 40x.when the proper site / orientation within the brain is reached , continue sectioning the epoxy resin block with a diamond knife to cut ultrathin sections ( ~ 70 nm ; figure 1e)use easily identifiable anatomic structures in and around the brain , including olfactory pits , eyes , grey - white matter boundaries , to identify the region of interest during ultrathin sectioning and to adjust the sectioning angle when the sample is tilted.mount section on single slot l2 x 1 copper grids ( figure 1f ) , to allow acquisition uninterrupted by grid bars .
contrasting
stain ultrathin sections on grids for 2 min in 2% uranyl acetate in methanol followed by reynolds lead citrate for another 2 min .
sectioning
section epoxy resin block using an ultramicrotome.use a glass knife or a diamond histoknife to cut semithin sections ( 500 nm ) for toluidine blue / basic fuchsin ( figure 1d ) staining to detect the right positioning.transfer semi - thin sections on microscopic slides by picking them up with a glass pasteur pipet
stain for 10 sec with 1% toluidine blue in water on a hot plate and after rinsing with water , stain for 10 sec with 0.05% basic fuchsin in 1% sodium tetraborate .
examine with a normal light microscope at 10x to 40x.when the proper site / orientation within the brain is reached , continue sectioning the epoxy resin block with a diamond knife to cut ultrathin sections ( ~ 70 nm ; figure 1e)use easily identifiable anatomic structures in and around the brain , including olfactory pits , eyes , grey - white matter boundaries , to identify the region of interest during ultrathin sectioning and to adjust the sectioning angle when the sample is tilted.mount section on single slot l2 x 1 copper grids ( figure 1f ) , to allow acquisition uninterrupted by grid bars .
use a glass knife or a diamond histoknife to cut semithin sections ( 500 nm ) for toluidine blue / basic fuchsin ( figure 1d ) staining to detect the right positioning .
transfer semi - thin sections on microscopic slides by picking them up with a glass pasteur pipet whose tip has been closed by melting in a flame .
stain for 10 sec with 1% toluidine blue in water on a hot plate and after rinsing with water , stain for 10 sec with 0.05% basic fuchsin in 1% sodium tetraborate .
when the proper site / orientation within the brain is reached , continue sectioning the epoxy resin block with a diamond knife to cut ultrathin sections ( ~ 70 nm ; figure 1e ) use easily identifiable anatomic structures in and around the brain , including olfactory pits , eyes , grey - white matter boundaries , to identify the region of interest during ultrathin sectioning and to adjust the sectioning angle when the sample is tilted . mount section on single slot l2 x 1 copper grids ( figure 1f ) , to allow acquisition uninterrupted by grid bars .
contrasting
stain ultrathin sections on grids for 2 min in 2% uranyl acetate in methanol followed by reynolds lead citrate for another 2 min .
stain ultrathin sections on grids for 2 min in 2% uranyl acetate in methanol followed by reynolds lead citrate for another 2 min .
large scale stem note : we use scanning em with an external scan generator capable of acquiring multiple large fields of view at high resolution using stem detection .
typically , one image generated this way is equivalent to the fields of view of ~ 100 transmission electron microscope ( tem ) images , significantly reducing the amount of stitching .
mounting sample in microscopeplace grid with section in the multiple grid sample holder and transfer into the chamber of the sem.alignment of the stem detectorput the grid with the sample under the beam and move it up so it will be approx .
acquire an image at 20 kv using the in - lens detector.focus on grid edge and adjust working distance to 4.0 mm.move the sample holder to a safe position and bring in the stem detector.center the hole of the stem detector in the image - field by turning the adjustments screws while imaging at maximum speed with the in - lens detector.carefully bring back the sample holder which will just fit between the lens pole and the detector.acquire an image with the in - lens detector to be sure to be on the section area.switch to stem detection ( gain medium and all quadrants set on ' minus ' ) and acquire an image and select the area to be scanned.raise acceleration voltage to 21 kv and wait for stabilization of the beam ( stable image again ) and then go to 29 kv in steps of 2 kv.acquiring imagespre - irradiate the sample ( to prevent brightness changes caused by the e - beam ) by zooming out so the complete area to be scanned fits the image window.change aperture to 120 m ( to keep the proper dynamic range the detector gains have to be reduced one step).de - focus so the image is blurred.make the scanned area as tight as possible using the reduced area scan option.set scan speed such that a frame is scanned in approx . 1 - 2 sec .
note : depending on the size and tissue this typically takes hr ( 100 x 100 m fov ) to up to 3 hr ( 1,000 x 500 m).zoom in at least 100x and scan a small area for 10 sec .
note : when this area does not change brightness compared to its surrounding , pre - irradiation is sufficient.bring back the 30 m aperture ( and stem gain on medium)focus the sample.align aperture using the wobbler ( at ~ 40,000x magnification).while in focus select the lightest area / feature , set scan speed such that details are visible.in the microscope software adjust brightness and contrast by carefully watching the histogram to keep all pixels in the dynamic range .
do the same for the darkest area / features.go back to the bright area and check again .
be on the safe side so there is some space on both sides of the histogram.zoom out so the complete area to be scanned fits the imaging window , and start the large area acquisition program.use the wizard option to set up a mosaic by selecting an area from the screen .
use dwell time 3 s for stem.select option " autofocus on previous tile " , use the large scale acquisition software autofocus with default company settings , check box " verify setting prior to execution " and define where to save the data.press " optimize " to check microscope settings .
this might be up to 72 hr for 1 x 0.5 mm areas.in window " maximum tile resolution " type 20,000 so individual tiles will not be bigger than 20k x 20k , preventing blunt edge effects . press
" execute".when asked for checking focus and brightness / contrast ( b / c ) , switch off external scan generator and carefully adjust focus and astigmatism in the microscope software .
note : the stage can be moved and magnification changed , but magnification has to be set back to the desired pixel size.switch on external scan generator again and press " continue " .
mounting sample in microscopeplace grid with section in the multiple grid sample holder and transfer into the chamber of the sem .
place grid with section in the multiple grid sample holder and transfer into the chamber of the sem .
alignment of the stem detectorput the grid with the sample under the beam and move it up so it will be approx .
acquire an image at 20 kv using the in - lens detector.focus on grid edge and adjust working distance to 4.0 mm.move the sample holder to a safe position and bring in the stem detector.center the hole of the stem detector in the image - field by turning the adjustments screws while imaging at maximum speed with the in - lens detector.carefully bring back the sample holder which will just fit between the lens pole and the detector.acquire an image with the in - lens detector to be sure to be on the section area.switch to stem detection ( gain medium and all quadrants set on ' minus ' ) and acquire an image and select the area to be scanned.raise acceleration voltage to 21 kv and wait for stabilization of the beam ( stable image again ) and then go to 29 kv in steps of 2 kv .
put the grid with the sample under the beam and move it up so it will be approx .
center the hole of the stem detector in the image - field by turning the adjustments screws while imaging at maximum speed with the in - lens detector .
carefully bring back the sample holder which will just fit between the lens pole and the detector . acquire an image with the in - lens detector to be sure to be on the section area . switch to stem detection ( gain medium and all quadrants set on ' minus ' ) and acquire an image and select the area to be scanned
raise acceleration voltage to 21 kv and wait for stabilization of the beam ( stable image again ) and then go to 29 kv in steps of 2 kv .
acquiring imagespre - irradiate the sample ( to prevent brightness changes caused by the e - beam ) by zooming out so the complete area to be scanned fits the image window.change aperture to 120 m ( to keep the proper dynamic range the detector gains have to be reduced one step).de - focus so the image is blurred.make the scanned area as tight as possible using the reduced area scan option.set scan speed such that a frame is scanned in approx .
1 - 2 sec . note : depending on the size and tissue this typically takes hr ( 100 x 100 m fov ) to up to 3 hr ( 1,000 x 500 m).zoom in at least 100x and scan a small area for 10 sec .
note : when this area does not change brightness compared to its surrounding , pre - irradiation is sufficient.bring back the 30 m aperture ( and stem gain on medium)focus the sample.align aperture using the wobbler ( at ~ 40,000x magnification).while in focus select the lightest area / feature , set scan speed such that details are visible.in the microscope software adjust brightness and contrast by carefully watching the histogram to keep all pixels in the dynamic range .
do the same for the darkest area / features.go back to the bright area and check again .
be on the safe side so there is some space on both sides of the histogram.zoom out so the complete area to be scanned fits the imaging window , and start the large area acquisition program.use the wizard option to set up a mosaic by selecting an area from the screen .
use dwell time 3 s for stem.select option " autofocus on previous tile " , use the large scale acquisition software autofocus with default company settings , check box " verify setting prior to execution " and define where to save the data.press " optimize " to check microscope settings .
this might be up to 72 hr for 1 x 0.5 mm areas.in window " maximum tile resolution " type 20,000 so individual tiles will not be bigger than 20k x 20k , preventing blunt edge effects .
press " execute".when asked for checking focus and brightness / contrast ( b / c ) , switch off external scan generator and carefully adjust focus and astigmatism in the microscope software . do not change b / c .
note : the stage can be moved and magnification changed , but magnification has to be set back to the desired pixel size.switch on external scan generator again and press " continue " . pre - irradiate the sample ( to prevent brightness changes caused by the e - beam ) by zooming out so the complete area to be scanned fits the image window .
change aperture to 120 m ( to keep the proper dynamic range the detector gains have to be reduced one step )
make the scanned area as tight as possible using the reduced area scan option . set scan speed such that a frame is scanned in approx
note : depending on the size and tissue this typically takes hr ( 100 x 100 m fov ) to up to 3 hr ( 1,000 x 500 m ) .
note : when this area does not change brightness compared to its surrounding , pre - irradiation is sufficient . bring back the 30 m aperture ( and stem gain on medium ) align aperture using the wobbler ( at ~ 40,000x magnification ) .
while in focus select the lightest area / feature , set scan speed such that details are visible . in the microscope software adjust brightness and contrast by carefully watching the histogram to keep all pixels in the dynamic range .
be on the safe side so there is some space on both sides of the histogram . zoom out so the complete area to be scanned fits the imaging window , and start the large area acquisition program . use the wizard option to set up a mosaic by selecting an area from the screen .
. select option " autofocus on previous tile " , use the large scale acquisition software autofocus with default company settings , check box " verify setting prior to execution " and define where to save the data .
this might be up to 72 hr for 1 x 0.5 mm areas . in window
" maximum tile resolution " type 20,000 so individual tiles will not be bigger than 20k x 20k , preventing blunt edge effects . press " execute " .
when asked for checking focus and brightness / contrast ( b / c ) , switch off external scan generator and carefully adjust focus and astigmatism in the microscope software . do not change b / c .
note : the stage can be moved and magnification changed , but magnification has to be set back to the desired pixel size .
open large - scale em file viewer program and open the file " mosaic info "
this preferably is performed on another workstation to not obstruct new acquisitions . choose option ' auto stitch entire mosaic ( parameters overlap mode on half , stitching threshold 0.90 , noise reduction automatic . in case stitching criteria can not be fulfilled , zoom in and manually place tile in position and click ' continue as is ' ) .
perform annotations in the tif file by opening it in an image editing program . in parallel , open the zoomable html file in a web browser for optimal resolution observation .
large - scale em dataset of coronal sections of the head of 1-week - old zebrafish larvae shows many tissue and cellular features in a single large scale image ( www.nanotomy.org ) .
nanotomy of control brain sections reveals typical ultrastructural features of neural tissue of the rostral forebrain including olfactory fiber bundles , neuronal nuclei and neuronal sub - compartments including synapses ( figure 2a , www.nanotomy.org ) .
cell types in the head that can be distinguished include chondrocytes with large vacuoles in the lower jaw , osmiophilic myelin of the olfactory nerve cells , endothelial cells of a small vessel , structures include the meninx ( the zebrafish counterpart of the meninges , the membranous layer encasing the mammalian brain ) .
subcellular structures include the glycocalyx of the epidermis , different nuclear morphologies and foci in different cell types and organelles including golgi apparatus , endoplasmic reticulum ( er ) , mitochondria and synaptic vesicles and post - synaptic densities .
unexpectedly the nuclei of cells lining the ventricle are very electron dense compared to other cells dispersed more laterally in the brain .
additionally , these ventricular nuclei show dark foci that are absent in other cells in the brain and appear different in size and structure from the heterochromatin , which is found in nuclei of phagocytic microglia ( figure 2 ) .
cells lining the ventricle in developing zebrafish include mostly radial glial cells and neuronal progenitors , which may reflect an altered chromatin state than more differentiated cells .
as stem cells in tissue are generally quite rare , nanotomy to correlate tissue labeling for stem cell markers with tissue scale em could therefore be used to identify ultrastructural features of stem cells .
large - scale em ( www.nanotomy.org ) of a coronal section in a zebrafish larva undergoing neuronal ablation reveals many specific tissues , and cellular and molecular features not found in control animals .
cellular features include phagocytic microglia and vacuoles the size of cells , likely representing dying cells ( figure 2b , www.nanotomy.org ) .
characteristic features of microglia include elongated nuclei , clumps of patchy chromatin next to the nuclear envelope , prominent golgi apparatus , free polyribosomes , granular endoplasmic reticulum ( er ) with long narrow cisternae , relatively dark / dense cytoplasm , and numerous inclusions , such as phagosomes , lipid droplets and lysosomes .
all these hallmarks , attributed to microglia in mammalian tissues , were also found in these cells in zebrafish brains ( figure 2b , www.nanotomy.org ) .
( d ) representative semithin toluidine blue stained section showing two side - by - side embedded zebrafish larvae .
( f ) edited image in ( d ) of whole zebrafish larval brain section on one - hole grid to indicate positioning . (
figure 2:nanotomy results : from macromolecule to tissue.(a ) nanotomy of brains of 7 days post fertilization control and ( b ) treated ( neuronal ablation ; figure 1 ) , showing features specific to the neuronal ablated degenerative brain .
( b ) these include phagocytic microglia , dark cells undergoing cell death and spongy appearance of neural tissue ( ( a ) and ( b ) ) . upper panels ( adapted from ): 10x magnified view of region indicated in middle panels .
( a , middle panel ) high magnification view of neuropil showing synapse in ( a , lower panel ) , synaptic vesicles ( svs ) and postsynaptic density ( pd ) .
( b , middle panel ) high magnification view of amoeboid microglia or possibly a macrophage ( middle panel , m ) showing typical amoeboid microglial features ( lower panel ) including prominent golgi apparatus ( g ) , inclusions including lysosomal vacuoles ( l ) .
scale bars : 50 m ( top ) , 5 m ( middle ) and 0.5 m ( bottom ) .
please click here to view a larger version of this figure , or visit the full data online ( nanotomy.org ) .
larger scale 3d em is particularly suitable for mapping neuronal connectivity by creating nanoscale resolution 3 dimensional reconstructions , requiring complex data processing .
in contrast , 2d large scale em requires only a single section and stitching of the imaging data , and assessment of the data is possible by anyone with access to an internet browser .
as for most approaches , tem and sem - based stitching do have their own advantages . here ,
scanning transmission em ( stem ) was used that allows generation of a large field of view at high resolution .
typically , one stem image is equivalent to the fields of view of approximately 100 tem images , significantly reducing the amount of stitching when imaging large fields of view at high resolution .
stem has the advantage over tem that non - contrasted samples can be used with good ultrastructural contrast .
additionally , the method described here can be simply adjusted for use with back scattered electron detection ( bsd ) on sections mounted on silica wafers , broadening the use to multiple microscope systems .
html - zoomable tissue em files are very useful for quantification , sharing data that may not have been analyzed to its full content , combining lm and em data ( clem ) , presentation purposes in scientific research , to analyze patient data , and for education .
alternatively , in large - scale em in a sem , but not in a tem , silica wafers can be used , which has two main advantages : bsd can be used , which is more generally available on scanning electron microscopes than stem detection .
second , mounting of large sections ( > 1 mm areas of interest ) is straightforward .
a disadvantage of bsd imaging is that , compared to stem , images have increased noise .
this can partly be compensated by increasing the pixel dwell time , resulting in much longer acquisition times .
although for sample preparation relatively standard em processing ( fixation , embedding and sectioning ) is needed , it is technically challenging to cut large ultrathin sections completely devoid of artifacts .
sections are very fragile , easily break , fold or are destroyed during imaging , which typically takes multiple hours per dataset . however , because of the online sharing of the raw unbiased data , it should become possible to compare more easily to published data , and use published dataset in the open domain as controls
. currently , few em devices capable of large - scale analysis are in use , and therefore accessibility to this technique is somewhat limited , though most imaging centers welcome collaborative efforts . for large - scale sections the tissue has to be properly fixed throughout the sample .
that is why a mixture of the fast but moderate fixative pfa is used in combination with the slow but strong fixative ga .
working with wafers in combination with bsd is easier compared to collecting sections on single hole grids .
heavy metal post staining is more critical compared to classical em . since the whole section is imaged every artifact will be visible . tem users typically find it difficult to switch to a sem , because of the difference in microscope operation .
the possibility to zoom in and out of large - scale images readily allows identification of cells of interest , which can be followed by nanoscale measurements inside the cells .
these datasets indicate that specific cell types can be rapidly identified and quantified in an unbiased manner in these large tissue sections , based on features detectable at different scales .
subsequently , upon zooming in on the individual cells , nanoscale subcellular and molecular features of these cells can be measured within the same dataset , as we previously showed for er width within a large scale em tissue culture dataset .
an additional advantage of nanotomy is that hosting of large scale datasets online will allow others to inspect the data , maybe for other features , and draw their conclusions on new hypothesis .
clem - in addition to facilitating quantitative em , large scale em makes it easier to correlate light microscopic labeling to em level . in the present example
a major question in neuroscience is what the individual functions and contributions are of microglia and potential other sources of phagocytic and immune cells .
unfortunately , it is difficult to selectively label microglia in particular in a pathological setting , as they exhibit large overlap with other immune cells in gene expression , morphology and function .
therefore , it is unclear whether and when microglia at the ultrastructural level differ from immune cells from other sources including monocyte derived infiltrating macrophages . understanding whether there are ultrastructural differences between these cells will provide a starting point for analysis of functional differences . combining selective transgenic or expression markers and clem allows detection of ultrastructural features selective to specific populations .
diagnosis & presentation and education - by visualizing nanoscale to microscale within a single dataset em data is greatly facilitated to a broad audience . with the increased possibilities and tools for correlative and large - scale em we anticipate a revival of em in basic and medical research .
our method represented here is applied to a zebrafish brain injury model , but has been used on human tissue , rat brain , in a rat model for diabetes and in cell culture , and can also be used in combination with a tem - based approach showing the versatility of this method .
the microscope operator is no longer recording highly selected , and hence biased images , but all numerous ultrastructural features are recorded and open for worldwide analysis .
Output:
| large - scale 2d electron microscopy ( em ) , or nanotomy , is the tissue - wide application of nanoscale resolution electron microscopy .
others and we previously applied large scale em to human skin pancreatic islets , tissue culture and whole zebrafish larvae1 - 7 . here
we describe a universally applicable method for tissue - scale scanning em for unbiased detection of sub - cellular and molecular features .
nanotomy was applied to investigate the healthy and a neurodegenerative zebrafish brain .
our method is based on standardized em sample preparation protocols : fixation with glutaraldehyde and osmium , followed by epoxy - resin embedding , ultrathin sectioning and mounting of ultrathin - sections on one - hole grids , followed by post staining with uranyl and lead .
large - scale 2d em mosaic images are acquired using a scanning em connected to an external large area scan generator using scanning transmission em ( stem ) .
large scale em images are typically ~ 5 - 50 g pixels in size , and best viewed using zoomable html files , which can be opened in any web browser , similar to online geographical html maps .
this method can be applied to ( human ) tissue , cross sections of whole animals as well as tissue culture1 - 5 . here
, zebrafish brains were analyzed in a non - invasive neuronal ablation model .
we visualize within a single dataset tissue , cellular and subcellular changes which can be quantified in various cell types including neurons and microglia , the brain 's macrophages .
in addition , nanotomy facilitates the correlation of em with light microscopy ( clem)8 on the same tissue , as large surface areas previously imaged using fluorescent microscopy , can subsequently be subjected to large area em , resulting in the nano - anatomy ( nanotomy ) of tissues . in all
, nanotomy allows unbiased detection of features at em level in a tissue - wide quantifiable manner . |
PubmedSumm6538 | ***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: healthy male and female volunteers , 1870 years of age , were recruited from the greater baton rouge , louisiana area .
eligible participants were free of chronic disease with fasting serum glucose levels of 125 mg / dl and a bmi between 25 and 35 kg / m .
the study was approved by the institutional review board at pennington biomedical research center ; all subjects provided written informed consent .
all foods were prepared and provided by the pennington metabolic kitchen core . for each diet period , participants were fed a standard american diet ( 34% fat , 15% protein , 51% carbohydrate ) for 3 days in order to control for diet prior to test days .
clinicians often recommend that patients consume a diet rich in carbohydrates prior to oral glucose tolerance testing ( 6 ) .
the energy level of the diet was individualized based on each participant s estimated resting metabolic rate .
lunch was provided as takeout . on day 4 , participants consumed all their meals for their assigned diet in clinic .
participants were asked to consume their meals within 20 min with breakfast centered at 8:00 a.m. lunch was provided 4 h following completion of breakfast and dinner 4 h following completion of lunch .
one daily menu , including breakfast , lunch , and dinner , was constructed for four isocaloric diets differing in gl by manipulation of gi based on white bread values and percent energy from carbohydrate .
dietary fiber was also held constant among diets with the addition of cellulose when needed .
the meals consisted of mixed foods ( casseroles ) that matched the diets gi and percent energy from carbohydrate as closely as possible .
table 1 provides a summary of the test diets ( high gi , high carbohydrate [ hgi - hc ] ; high gi , low carbohydrate [ hgi - lc ] ; low gi , high carbohydrate [ lgi - hc ] ; and low gi , low carbohydrate [ lgi - lc ] ) .
gi , gl , energy , macronutrient , and fiber content of each diet at the 2,200-kcal energy level on day 4 , after a 10-h fast , blood samples were drawn via indwelling catheter beginning just before breakfast and at timed intervals thereafter for 12 h. a baseline blood sample was obtained 15 min prior to breakfast consumption .
additional blood samples were collected at 15 , 30 , 45 , 60 , 90 , 120 , 150 , and 210 min after eating commenced .
subjective appetite sensations and mood were assessed using visual analog scales ( vas ) as previously described ( 7 ) .
participants were asked to rate their levels of hunger , satiety , energy , and mood using the questions listed in table 2 .
questions were presented one at a time , and subjects marked their rating on a 100-mm line anchored at 0 ( i am not hungry at all ) and 100 ( i have never been more hungry ) .
vas ratings of satiety , energy , and emotions the minimum clinically relevant difference between any two levels of treatment for incremental area under the curve ( auc ) for serum glucose is taken to be 25% of the mean levels under standard diet conditions ( 8) .
a sample size of 25 subjects gives 80% power to detect a 25% difference between treatments with a significance level of = 0.05 .
this model included auc as the dependent variable and fixed effects for the four treatments , the 4 days , and the four sequences together with random effects for subjects within sequence as independent ( predictor ) variables .
statistical significance was defined as p 0.05 , and pairwise comparisons of the four treatments were performed using a tukey adjustment .
healthy male and female volunteers , 1870 years of age , were recruited from the greater baton rouge , louisiana area .
eligible participants were free of chronic disease with fasting serum glucose levels of 125 mg / dl and a bmi between 25 and 35 kg / m .
the study was approved by the institutional review board at pennington biomedical research center ; all subjects provided written informed consent .
all foods were prepared and provided by the pennington metabolic kitchen core . for each diet period , participants were fed a standard american diet ( 34% fat , 15% protein , 51% carbohydrate ) for 3 days in order to control for diet prior to test days . clinicians often recommend that patients consume a diet rich in carbohydrates prior to oral glucose tolerance testing ( 6 ) .
the energy level of the diet was individualized based on each participant s estimated resting metabolic rate .
participants were asked to consume their meals within 20 min with breakfast centered at 8:00 a.m. lunch was provided 4 h following completion of breakfast and dinner 4 h following completion of lunch .
one daily menu , including breakfast , lunch , and dinner , was constructed for four isocaloric diets differing in gl by manipulation of gi based on white bread values and percent energy from carbohydrate .
dietary fiber was also held constant among diets with the addition of cellulose when needed .
the meals consisted of mixed foods ( casseroles ) that matched the diets gi and percent energy from carbohydrate as closely as possible .
table 1 provides a summary of the test diets ( high gi , high carbohydrate [ hgi - hc ] ; high gi , low carbohydrate [ hgi - lc ] ; low gi , high carbohydrate [ lgi - hc ] ; and low gi , low carbohydrate [ lgi - lc ] ) .
gi , gl , energy , macronutrient , and fiber content of each diet at the 2,200-kcal energy level
on day 4 , after a 10-h fast , blood samples were drawn via indwelling catheter beginning just before breakfast and at timed intervals thereafter for 12 h. a baseline blood sample was obtained 15 min prior to breakfast consumption .
additional blood samples were collected at 15 , 30 , 45 , 60 , 90 , 120 , 150 , and 210 min after eating commenced .
subjective appetite sensations and mood were assessed using visual analog scales ( vas ) as previously described ( 7 ) .
participants were asked to rate their levels of hunger , satiety , energy , and mood using the questions listed in table 2 .
questions were presented one at a time , and subjects marked their rating on a 100-mm line anchored at 0 ( i am not hungry at all ) and 100 ( i have never been more hungry ) .
the minimum clinically relevant difference between any two levels of treatment for incremental area under the curve ( auc ) for serum glucose is taken to be 25% of the mean levels under standard diet conditions ( 8) .
a sample size of 25 subjects gives 80% power to detect a 25% difference between treatments with a significance level of = 0.05 .
this model included auc as the dependent variable and fixed effects for the four treatments , the 4 days , and the four sequences together with random effects for subjects within sequence as independent ( predictor ) variables .
statistical significance was defined as p 0.05 , and pairwise comparisons of the four treatments were performed using a tukey adjustment .
thirty participants were enrolled in the study between february and june 2007 with a total of 26 completing .
two participants changed their minds , one participant discontinued because of a schedule conflict , and one participant was not able to meet the study demands .
the average age of participants was 43.5 14.7 years , and the average bmi was 29.1 2.8 kg / m .
baseline characteristics of the study participants are shown in supplementary table 5 . the daylong ( 12 h ) glucose and insulin profiles are shown in supplementary fig . 1 .
mean glucose and insulin auc values for all meals combined were significantly higher for the hgi - hc compared with all other diets ( fig .
was reduced 24 , 33 , and 42% in the hgi - lc , lgi - hc , and lgi - lc treatments , respectively ( p < 0.001 for all comparisons ) .
serum insulin auc was 20 , 20 , and 29% lower in the hgi - lc , lgi - hc , and lgi - lc treatments as compared with the hgi - hc diet ( p < 0.0001 for all comparisons ) .
using criteria of at least a 25% change from mean levels , the lgi - lc diet produced the largest clinically relevant reductions in serum glucose and insulin .
not surprisingly , consumption of the hgi - lc ( gl = 77 ) and lgi - hc ( gl = 69 ) diets resulted in glucose and insulin aucs that were intermediate to the hgi - hc ( gl = 108 ) and lgi - lc ( gl = 50 ) diets .
glucose and insulin auc values for all meals combined ( mean 95% ci ; n = 26 ) .
glucose and insulin auc values for breakfast , lunch , and dinner ( mean 95% ci ; n = 26 ) .
the hgi - hc breakfast meal yielded the highest levels of circulating glucose , and levels for all other diets were equally reduced compared with hgi - hc diet .
blood insulin levels were higher in response to both high - carbohydrate diets regardless of gi . at lunch ,
the effect of gi on glucose and insulin levels became more pronounced , and a distinct dose - response relationship between glucose or insulin auc and gl was apparent .
we measured subjective hunger , fullness , and satiety using vas throughout the course of the day .
as an exploratory measure , we also asked subjects to answer several questions related to energy levels and emotions .
participants rated their levels of weariness higher when they consumed the lgi - lc diet compared with the hgi - hc diet ( p < 0.05 ) .
participants also felt that doing anything took more effort when they were consuming the lgi - lc diet compared with the lgi - hc and hgi - lc diets ( p < 0.05 ) .
calmness ratings were highest in the lgi - hc treatment , whereas sadness ratings were highest in the hgi - lc treatment . with most of the ratings
thirty participants were enrolled in the study between february and june 2007 with a total of 26 completing .
two participants changed their minds , one participant discontinued because of a schedule conflict , and one participant was not able to meet the study demands .
the average age of participants was 43.5 14.7 years , and the average bmi was 29.1 2.8 kg / m .
the daylong ( 12 h ) glucose and insulin profiles are shown in supplementary fig . 1 . mean glucose and insulin auc values for all meals combined were significantly higher for the hgi - hc compared with all other diets ( fig .
was reduced 24 , 33 , and 42% in the hgi - lc , lgi - hc , and lgi - lc treatments , respectively ( p < 0.001 for all comparisons ) .
serum insulin auc was 20 , 20 , and 29% lower in the hgi - lc , lgi - hc , and lgi - lc treatments as compared with the hgi - hc diet ( p < 0.0001 for all comparisons ) .
using criteria of at least a 25% change from mean levels , the lgi - lc diet produced the largest clinically relevant reductions in serum glucose and insulin .
not surprisingly , consumption of the hgi - lc ( gl = 77 ) and lgi - hc ( gl = 69 ) diets resulted in glucose and insulin aucs that were intermediate to the hgi - hc ( gl = 108 ) and lgi - lc ( gl = 50 ) diets .
glucose and insulin auc values for all meals combined ( mean 95% ci ; n = 26 ) . glucose and insulin auc values for breakfast , lunch , and dinner
the hgi - hc breakfast meal yielded the highest levels of circulating glucose , and levels for all other diets were equally reduced compared with hgi - hc diet .
blood insulin levels were higher in response to both high - carbohydrate diets regardless of gi . at lunch ,
the effect of gi on glucose and insulin levels became more pronounced , and a distinct dose - response relationship between glucose or insulin auc and gl was apparent .
we measured subjective hunger , fullness , and satiety using vas throughout the course of the day . there were no differences between dietary treatments in these measures ( table 2 ) .
as an exploratory measure , we also asked subjects to answer several questions related to energy levels and emotions .
participants rated their levels of weariness higher when they consumed the lgi - lc diet compared with the hgi - hc diet ( p < 0.05 ) .
participants also felt that doing anything took more effort when they were consuming the lgi - lc diet compared with the lgi - hc and hgi - lc diets ( p < 0.05 ) .
calmness ratings were highest in the lgi - hc treatment , whereas sadness ratings were highest in the hgi - lc treatment . with most of the ratings
this study is unique in that we fed well - defined meals to overweight or obese subjects throughout an entire day and compared a low gi diet to a high gi diet with percent energy from carbohydrate at two levels ( 40 and 56% ) .
thus , the gl varied for all diets . we were also able to control for any effects of previous diet by having participants consume standard diets for the 3 days prior to testing .
overall consumption of the low gi diets resulted in glucose and insulin aucs that were lower than that aucs induced by high gi diets regardless to whether it was high or low in percent energy from carbohydrates .
our results are in agreement with previous literature including a recent study by bao et al .
( 9 ) , which demonstrated that gl is a good predictor of postprandial serum glucose and insulin response in healthy , lean adults . in that study
, groups of subjects consumed 121 single food items and 13 mixed meals , and glucose and insulin response was quantified as auc . among single foods ,
gl explained 85 and 59% of the observed variation in glucose and insulin response , respectively ( p < 0.001 ) . among mixed meals , gl explained 58% ( p = 0.003 ) and 46% ( p = 0.01 ) of the variation in glucose and insulin response , respectively .
our study suggests that the gl remains a good predictor of postprandial serum and glucose levels in an overweight and obese population .
interestingly , despite significant reductions in postprandial glycemia and insulinemia with decreasing gl , there was no effect on measures of hunger or satiety . though this does not support the hypothesis that blood glucose levels mediate appetite , our findings are in agreement with the handful of studies that have examined the effect of low or high gi mixed meals on hunger and satiety ratings ( 1013 ) .
all studies except one report no effect of low versus high gi meals on hunger and satiety ratings .
( 14 ) previously demonstrated that blood glucose and insulin tracked with vas scores , but the amount of variation explained by these blood markers was too small to serve as a useful biomarker .
( 15 ) found no correlation between blood glucose concentrations and feelings of hunger or satiety .
our study was limited in that we were only able to assess subjective measures of hunger and satiety .
quantifying caloric intake in an ad libitum setting would have allowed for objective measurement of food intake .
however , other studies have reported no differences in calories consumed at ad libitum meals when subjects are prefed a low or high gi test meal ( 10,12,13,16 ) .
although we did see some statistically significant changes in parameters related to mood and energy , the physiological significance is questionable due to the lack of a clear relationship with gi or gl .
based on our data , it does not appear that blood glucose levels are a significant modulator of mood or energy levels .
this study demonstrates that lowering the gl of mixed meals is an effective method of controlling blood glucose and insulin levels throughout the day .
Output:
| objectivewe evaluated the effects of mixed meals differing in glycemic index ( gi ) and carbohydrate content on postprandial serum glucose and insulin response , hunger , and satiety over the course of a 12-h day.research design and methodsin this randomized crossover trial , 26 overweight or obese adults received four diets in random order ( high gi , high carbohydrate [ hgi - hc ] ; high gi , low carbohydrate [ hgi - lc ] ; low gi , high carbohydrate [ lgi - hc ] ; and low gi , low carbohydrate [ lgi - lc ] ) .
all meals were prepared by a metabolic kitchen .
participants received breakfast , lunch , and dinner over the course of a 12-h day .
primary outcomes were postprandial serum glucose and insulin quantified as area under the curve .
hunger , fullness , and satiety were assessed by visual analog scale.resultsthe hgi - lc , lgi - hc , and lgi - lc diets significantly reduced glucose and insulin area under the curve compared with the hgi - hc diet ( p < 0.001 for all comparisons ) . there were no significant differences in ratings of hunger , fullness , or satiety between the different dietary treatments.conclusionsreducing the gi or carbohydrate content of mixed meals reduces postprandial glycemia and insulinemia , and these changes can be sustained over the course of an entire day .
however , there were no differences in subjective hunger and satiety ratings between the diets .
these results demonstrate that maintaining a low gi or glycemic load diet is an effective method of controlling serum glucose and insulin levels . |
PubmedSumm6539 | ***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: symptomatic cerebral air embolism ( cae ) is a rare complication associated with cerebral angiography with a reported incidence of 0.08%.2 ) clinical manifestations of symptomatic cae may include decreased level of consciousness , hemiparesis , seizures , and neuromonitoring changes while under anesthesia.6 ) early recognition , diagnosis , and treatment of cae can minimize irreversible neurological deficits and avoid potential mortality .
we report on a rare case of cae , which highlights that symptomatic cae should be considered in differential diagnoses when abnormal neuromonitoring signals are observed during cerebral angiography and prompt treatment can minimize neurological deficits .
a 69-year - old female presented for elective stent - assisted coiling of a 7 mm , unruptured right middle cerebral artery ( mca ) bifurcation aneurysm .
she was started on aspirin 325 mg and clopidogrel 75 mg daily seven days prior to undergoing the elective procedure .
neuromonitoring with electroencephalography ( eeg ) and somatosensory evoked potential ( ssep ) were set up with good quality baseline signals prior to starting the procedure . a 6-french neuron guide catheter ( penumbra inc . ,
alameda , ca , usa ) was advanced over a 5-french berenstein catheter for selection of the patient 's right common carotid artery . using a roadmap technique and over - the - wire technique ,
the diagnostic catheter was used for selection of the patient 's right internal carotid artery .
a microcatheter ( excelsior sl-10 , stryker neurovascular , fremont , ca , usa ) and a wire ( synchro-14 , stryker neurovascular ) were then used for selective catheterization of the mca and coiling of the mca aneurysm was started . during coiling of the aneurysm however , the neurophysiologist reported severe attenuation of sseps in the bilateral upper and lower extremities along with near flatlining of the eeg .
there was no change in anesthetics , blood pressure , or body temperature prior to the ssep and eeg change .
an intraoperative dynact was then obtained and showed multiple , hypodense cortical vessels consistent with cerebral air embolism ( fig .
, it was noted that the pressure bag was depleted and a small amount of air was present in the drip line tubing .
the fio2 was increased to 100% on the ventilator , intravenous levetiracetam was administered , mean arterial blood pressure was increased , and intra - arterial verapamil infusion was administered in order to facilitate vasodilatation and to maximize cerebral perfusion .
the ssep and eeg signals showed gradual improvement approximately 30 minutes after the initial change .
given the patient 's improvement on neuromonitoring and risk of coil migration , an enterprise stent ( 4.5 22 mm ; cordis , bridgewater , nj , usa ) was deployed successfully across the aneurysm for completion of the procedure .
the catheter was retracted out of the body . a 6-french angio - seal closure device ( st . jude medical , st .
magnetic resonance imaging ( mri ) of the brain showed only a small focal area with restricted diffusion in the right parietal region ( fig .
the patient 's left hemiparesis showed gradual improvement over the next few days and she was eventually discharged with near baseline strength .
follow - up angiogram at four weeks showed raymond grade 1 occlusion of the right mca aneurysm ( fig .
cerebral air embolism is known to occur in a number of clinical settings , including cranial surgeries in the sitting position , trauma , decompression sickness , and cardiopulmonary bypass procedures.6 ) in many of these situations , air first enters into the venous circulation and subsequently migrates to the arterial side from either a patent foramen ovale or other cardiopulmonary shunts ( paradoxical embolism ) . during cerebral angiography ,
however , air can be introduced directly into the arterial circulation and therefore is more likely to cause neurological symptoms .
fortunately , the overall incidence of symptomatic cae associated with cerebral angiography is extremely low . in a study examining more than 4,500 cerebral angiographies , only four cases of symptomatic cae
of particular interest , all four cases of cae occurred during interventional cases and conferred a risk of 0.2%.2 ) several sources for air emboli in the setting of cerebral angiography have been reported in the literature , including air bubbles in the flush syringe , air bubbles in improperly primed flush tubing , non - degassed pressure bag , accidentally opened 3-way stopcock during an episode of hypotension , and rupture of an inadequately degassed angioplasty balloon.2)4 ) in our case , air was introduced from the pressure bag , which had been inadequately degassed prior to the procedure ; when the pressure bag was depleted , the small amount of residual air in the bag subsequently moved into the drip line , the guide wire , and eventually into the cerebral vasculatures .
when cae is suspected during cerebral angiography , a quick angiogram can be helpful in assessment for any large vessel occlusion .
computed tomography ( ct ) or dynact , if available , is a quick way to look for intracranial air , which can often demonstrate the outline of affected cerebral vasculature as the air emboli serve as a negative contrast medium .
mri can also demonstrate intracranial air as hypointensity on t1-weighted sequence , however , the time requirement and patient transport often limit its role in acute diagnosis of cae ; however , mri is valuable in assessing the extent of ischemic changes due to cae .
once the diagnosis of cae has been established , several measures can be taken to minimize potential neurological deficits . first , 100% o2 can be used to dilute nitrogen in the air emboli ( same composition as the earth 's atmosphere , ~ 78% n2 and 21% o2 ) and facilitate absorption of air .
second , mean arterial pressure can be raised to increase cerebral blood flow , which helps to increase perfusion of the affected area from collateral vessels and to increase the rate of air absorption .
third , as in our case , intra - arterial verapamil infusion can potentially increase cerebral vessel dilation to maximize cerebral perfusion and to facilitate more distal migration of air emboli .
another important treatment option for cae is placing the patient in a hyperbaric chamber , where increased pressure can decrease air emboli size and increase the amount of gas molecules dissolved in the blood stream .
however , the utilization of hyperbaric chambers is limited by availability . finally , early prophylactic anticonvulsants should also be considered , given that many patients with cae are prone to having seizures .
prevention of cae is paramount in every neurointerventional case and all potential sources for introduction of air into the drip line should be checked carefully prior to starting any procedure .
the prognosis of cae depends on a combination of several factors , including the amount of air present , collateral circulation , time of diagnosis , time of intervention , and treatment strategies utilized .
many patients with cae can have complete recovery ; however , permanent neurological injuries and mortality can also occur if diagnosis and proper intervention is delayed.1)2)3)4)5)6 )
symptomatic cerebral air embolism is a rare but important complication associated with cerebral angiography which all neurointerventional surgeons should bear in mind . with prompt
diagnosis and appropriate management , major permanent neurological deficits and mortality can often be avoided .
Output:
| symptomatic cerebral air embolism during cerebral angiography is extremely rare .
we report on the case of a 69-year - old woman undergoing elective stent - assisted coiling of an unruptured right middle cerebral artery ( mca ) bifurcation aneurysm , who was found to have severe attenuation of somatosensory evoked potential ( ssep ) and electroencephalography ( eeg ) during the procedure .
intra - operative dynact showed hypodense cortical vessels consistent with cerebral air embolism .
diagnostic and management strategies for this rare complication are reviewed . |
PubmedSumm6540 | ***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: phosphorus ( p ) is the 11th most abundant element of the earth s crust ; while simultaneously the most immobile nutrients in the soils resulting in in its poorly availability for plants .
the major available form of p for plants in the soils is inorganic p ( pi ) . to overcome pi deficiency ,
a massive pi supply is chosen as an immediate remedy , a practice that is neither ecologically sustainable nor economically viable .
interestingly , crops take up only 1530% of the applied pi fertilizer within the year of its application , whereas rest of the applied fertilizer is lost in form of leaching and polluting the water bodies . thus improving the ability of crops to use the available pi
is necessary to reduce a plant dependency on pi - fertilizers while maintaining an optimum yield .
such an objective requires a better understanding on mechanisms regulating both the pi transport system in plants and the root growth capacity in response to fluctuating pi concentrations in soil . during the last few decades ,
our knowledge on the transport of pi and its accumulation in plants has been considerably advanced , mainly using arabidopsis as a reference model plant [ 3 , 4 ] . for an extensive review of the pi transporter gene family
the physiological and molecular aspects of root growth and development in response to pi deficiency has been also investigated in arabidopsis ecotype columbia ( col ) .
low pi conditions have been shown to affect the course of root development in plants , for instance on low pi media , a reduction in primary root length as well as increase in lateral root length have been reported [ 8 - 11 ] .
these morphological changes have been opined to increase the root surface , thus enabling plants for the better exploration of the top layer of soil to improve the acquisition of the poorly mobile pi .
number of key genes involved in the primary root growth inhibition upon pi deficiency has been identified in arabidopsis through classical genetic ( reverse and forward ) studies . based on detailed mutant analysis
we can distinguish the following three categories , 1 ) mutants hypersensitive to low pi such as the phosphate deficiency response 2 mutant ( pdr2 , p5-type atpase , at5g23630 ) ; the siz1 mutant ( sumo e3 ligase , at5g60410 ) and the prd mutant ( dna binding protein , at1g79700 ) ; 2 ) mutants able to maintain primary root growth in low pi , such as the low phosphate root lpr mutants ( lpr1 , at1g23010 ; lpr2 , at1g71040 ; lpr3 ) and ; 3 ) mutants that are low phosphorus insensitive , namely lpi1 , lpi2 , lpi3 and lpi4 , which are characterized by a long primary root despite of low pi in the growth media . in general ,
low pi causes a redistribution of root growth from the primary root to the lateral roots and the later becoming denser [ 8 , 13 ] .
although this observation is overstated in some mutants such as the siz1 mutant displaying an increase of lateral root number , or the pdr2 and the ribonuclease polynucleotide phosphorylase mutant ( pnp , at3g03710 ) that presents highly branched lateral roots .
substantial natural variation of root developmental response to pi deficiency can be easily observed using hundreds of available accessions of arabidopsis genus .
numerous initiatives in the development of high - throughput plant phenotyping platforms using robotic - assisted imaging and computer vision - assisted analysis tools are engaged [ 15 , 16 ] .
the availability of the complete arabidopsis genome sequence has dramatically accelerated traditional genetic research on root biology , and has also enabled entirely new experimental strategies to be applied .
the availability of genome sequences of various plant species coupled with root phenotyping tools have allowed the emergence of the genome - wide association studies ( gwas ) as an excellent strategy to dissect the genetic basis of many plant traits in responses to abiotic stresses .
gwas combined with expression analyses , allows the identification of genomic regions and causal genes , associated with biological processes such as root development .
for instance , reports a cost - efficient phenotyping system for arabidopsis roots that enables scalable image acquisition and processing , as well as storing of positional information of plant genotypes and automated annotation of multiple genotypes per plate . the setup and evaluation of the performance of this system to produce and process a large data set as well as its robustness toward different growth conditions was discussed .
recently , this system was used and allowed the identification of a new f - box gene , kuk , involved in the regulation of root meristem and cell length .
the availability of nucleotide and protein sequences allowed the identification of the polymorphisms in the coding sequences as the major causes of kuk ( f - box ) allele dependent natural variation in root development .
therefore , gwas strategy has proved its reliability to explore the genetic determinants underlying the plasticity of root growth in response to pi availability .
pi starvation activates a large - scale change at the transcriptome and proteome levels in plant shoots and roots [ 19 , 20 ] .
gene expression profiles ( microarrays ) of a high - resolution set of developmental time points within a single arabidopsis root and a comprehensive map of nearly all root cell types has been reported .
these data revealed complex programs that define arabidopsis root development in both space and time .
it will very interesting to combines cell sorting with microarray analysis to generate the global expression pattern for every cell type in the root under pi deficiency conditions .
if this information could be obtained for every cell type and every developmental stage of the root grown under limited pi condition , it would provide an all - encompassing picture of the regulatory networks controlling root development . from this dataset
all transcription factors that are expressed in a tissue - specific pattern can be identified .
localizing these transcription factors and determining their immediate targets will be instrumental for a better understanding of complex biological systems such as root development . in conclusion ,
combination of the above mentioned innovative approaches will certainly complete the current understanding on genes and their regulatory network involved in the regulation of primary root development , but also others root traits in response to pi availability .
recent works have shown that the external , but not the internal , low - pi content conditions the primary root growth arrest ; this is a typical local response to low - pi [ 22 , 23 ] .
accumulating evidence indicates that the root tip plays a critical role for sensing and responding to pi starvation .
the physical contact of the root tip with low - pi medium is necessary and sufficient to severely reduce the root growth capacity .
the conditional short root phenotype of pdr2 under pi limitation can be rescued by supplementing the pi - limiting media with phosphite ( phi ) , which leads to resume the root meristem activity [ 25 , 26 ] .
the pdr2 gene ( p5-type atpase ) appears to function in the endoplasmic reticulum ( er ) and act as a pi sensitive checkpoint in root development in low pi media through the maintenance of the stem - cell fate .
pdr2 in pi - deprived roots is required for proper expression of a key regulator gene of root patterning , scarecrow ( scr ) , and affects short - root ( shr ) movement towards the endodermis .
it was also observed that prd , an arabidopsis aintegumenta - like gene , was involved in root architectural changes in response to pi starvation by controlling primary and lateral root elongation .
the low phosphate root1 ( lpr1 , ferroxidase ) , as its paralog lpr2 , are expressed in the root tip , comprising the meristem and root cap .
it is noteworthy that pdr2 and lpr1 expression domains overlap in the stem - cell niche and distal root meristem , which strengthens the hypothesis that these two genes function together in an er - resident pathway that adjusts root meristem activity in response to external pi . taken together , these data attest the critical role of the root tip in pi starvation response .
fortuitously , multiple sets of arabidopsis microarray data have been assembled in various available databases , as well as data mining and analysis tool boxes such as tair , nascarrays , the stanford microarray database and genevestigator .
these data sources can be combined with several meta - analysis tools using a guilt - by - association principle to help visualise correlated gene expression , such as atted - ii , and cressexpress .
the functional annotations in the gene 's co - expression neighbourhood can then be used to hypothesise a biologically relevant relationship . using atted ver7.1 ( http://atted.jp/ ) ,
the co - expression relationship of atlpr1 ( at1g23010 ) and atlpr2 ( at1g71040 ) and atpdr2 ( at5g23630 ) can be investigated .
interestingly , such an analysis revealed that lpr1 , lpr2 , and pdr2 genes constitute a different set of co - expressed genes , which illustrate the existence of co - expression clusters that correspond to different functional modules involved in regulation of root development . a comprehensive protein
protein interaction map would be another valuable resource that would help identifying new network connections .
variation in the experimental design and the composition of the growth media impacts the morphology of the roots of pi - deficient plants [ 10 , 11 , 35 ] .
concentrations of iron ( fe ) and other microelement contaminants in gelling agents cause significant variations in the morphological responses to pi deprivation .
therefore , the root phenotype could not be the only placemark to define status of pi in plants .
for example , similarly to low pi , fe deprivation induces an increase in root hair length and density [ 37 - 39 ] .
we have learned recently that the morphological changes in root architecture upon pi starvation are most likely an outcome of the complex interactions between pi and the fe [ 24 , 35 ] .
indeed , the pi - deprived plants over - accumulate fe , resulting supposedly to a fe toxicity effects in roots . in line with this statement , the reduction of fe concentration in the medium , in spite of low concentrations of pi , leads to the recovery of the primary root elongation and the ability of plant to uptake pi .
therefore , pi deficiency - induced root growth inhibition depends on external fe presence and is initiated by accelerated differentiation of elongating cells , followed by a decline in meristematic cells .
the molecular basis and the nature of the cross - talks between pi and fe homeostasis start to emerge .
very recently , reported that the two functionally interacting genes , lpr1 and pdr2 , facilitate cell - specific apoplastic fe and callose deposition in the meristem and elongation zone of primary roots upon pi limitation .
this work highlights the importance of callose - regulated symplastic communication in root meristems for the perception of pi availability , which likely depends on fe redox cycling .
however , taken into account that the inhibitory effect on the growth of pi - deprived pdr2 mutant roots was shown to be mostly independent of fe concentration in the media , it is thus clear that plants have evolved distinct pi - signalling pathways that are dependent and independent of metal ions availability .
in addition to fe , zinc ( zn ) availability in the growth media has also been shown to inversely impact the pi uptake and accumulation on plants [ 41 - 43 ] .
it will be interesting to decipher the root phenotype under conditions of pi availability linked with zn excess or deficiency conditions . to further address the question of a regulatory connection between ions signalling pathways and root growth capacity in arabidopsis thaliana , combination of bioinformatics , system biology , molecular genetics and genomics
experimental approaches should be more effective at unravelling complex cross - talk mechanisms compared to previous , single approach , studies .
the role of root hair in anchoring the plant to the soil is proposed but not fully established .
the ability of arabidopsis mutants affected in root hair development to adhere to the growth medium is compromised in the case of actin double mutant actin2actin7 ( act2act7 ; at3g18780 , at5g09810 ) , but not in the case of the root hair defective 2 ( rhd2 - 1 ; at5g51060 ) mutant , which is defective in nadph oxidase and hence ros production . nevertheless , the implication of root hair in the acquisition of nutrients from the soil solution is well established .
the importance of root hairs in the absorption of this element has been proven earlier using the arabidopsis mutants affected in root hair elongation ( rdh2 , at5g51060 ) or reduced root hair density ( rhd6 , at1g66470 ) [ 45 - 48 ] .
it is a proven fact that a plant increases its root hair length and density under pi deficiency .
these morphological changes can be seen as a strategy to further empower the capacity of a root system to explore more soil surface , to penetrate into the finest structures of the soil and to enhance the acquisition of available pi .
for instance , pi - deficient plants increase root hair density by the formation of shorter cells , resulting in a higher frequency of hairs per unit root length , and additional trichoblast cell fate assignment via increased expression of the enhancer of try and cpc ( etc1 , at1g01380 ) gene .
there is a growing list of arabidopsis genes involved in root hair proliferation in response to low pi condition .
mutants in these genes can promote root hair formation such as the sumo e3 ligase gene siz1 ( at5g60410 ) , the transcription factor genes ( wrky75 , at5g13080 ; bhlh32 , at3g25710 ) , the transcription factor phl1/phr1(at5g29000/at4g28610 ) .
other genes have been also identified including the f - box protein with wd40 domain ( fbx2 , at5g21040 ) , inositol polyphosphate kinase ( ipk , at5g42810 ) , raf like kinase ( hsp2 , at5g03730 ) , loss of heat shock protein ( hsp2 , at5g03730 ) , or the loss of the f - box gene bx2 ( at5g21040 ) .
mutants that also reduce and or inhibit root hair growth have been described for e.g. the ubiquitin protease ( ubp14/per1 , at3g20630 ) , gibberellin biosynthesis ( ga1 - 3 , at4g02780 ) , and the transcription factor ( rsl4 , at1g27740 ) . a recent study on the natural variation of the root hair responses to local scarcity of pi in a large panel of a. thaliana accessions ( 166 ) , using gwa mapping , allowed the identification of some accessions showing no root hair under pi deficiency or in the opposite longer / denser root hair formation under this condition .
gwas analysis revealed new genes involved in the response of root hairs to scarce local pi level including ( cyr1 , at1g32360 and rlp48 , at4g13880 ) . in the post
genomic area , root hair cells can be seen as a system biology model to investigate pi uptake , and response to pi deficiency at a plant cell level . a system model for root hairs should include gene regulatory and signal transduction networks , and metabolic pathways related to various aspects of root hair function .
to generate this knowledge , there is a need of methodological development and improvement . in method development ,
efficient ways to isolate and manipulate the fragile root hair cells is the first crucial step to generate the omics data . to date , the transcriptome data on isolated root hair cells have been reported only on limited number of plant species such as soybean .
analysis of transcriptome of root hair in presence or absence of pi , using the dna microarray hybridization and high - throughput sequencing technologies will help in obtaining the repertoire of gene expression which can be used for the identification of pi- specific regulatory genes . at the microscopic level ,
the observation of root hair , with minimal interference from surrounding cells , is feasible and enables the analysis of different biological processes related to root hair elongation under different pi regimes .
nevertheless , further method improvement is also needed to measure and visualize intercellular pi dynamics and pi signalling molecules accurately .
bioinformatics and systems biology are promising approaches to help integrating these large biological data sets .
the combination of traditional forward genetics , genomics and systems biology approaches emerge as a powerful strategy to uncover key players in ion signalling pathways crosstalk in plant .
these approaches were successfully used to predict network modeling of the high - resolution dynamic plant transcriptome in response to nitrate [ 59 , 60 ] .
such approaches , implemented as part of the adaptive response of the root system to the pi deficiency , should emerge original crosstalk between pi and plant hormone signalling pathways .
hormonal activities have been implicated in different developmental aspects of root growth under pi deficiency , with either promotive or repressive effects .
nevertheless , how pi signal interacts with those of others nutrients at the molecular level , is a largely unanswered question in plants .
the responses of the arabidopsis root system architecture to pi deficiency involve both auxin - dependent and auxin - independent mechanisms [ 8 , 10 , 13 , 39 , 62 , 63 ] . in a similar manner to wild type plants ,
all auxin - related mutants ( aux1 and eir1 , axr1 , axr2 and axr4 ) showed a decrease in primary root length as well as an increase in lateral root number and density in response to pi deficiency .
the only exception is the auxin response mutant iaa28 which is severely defective in lateral root formation in plants grown in either pi - sufficient or pi - deficient conditions .
lateral root formation in pi starvation appeared to require a class of transcriptional regulators that mediate growth and developmental responses to auxins auxin response factor 19 ( arf19 , at1g19220 ) and which involves an scftir1-dependent signalling mechanism . like wild type , the root hair elongation in the hairless auxin - resistant mutant axr1 and axr2 , as well as in the auxin - insensitive mutant aux1 ,
recent experimental evidences indicate that auxin could affect root architecture in pi - starved plants via modulation of the status of other phytohormones .
for example , it has been proposed that auxin may regulate root growth by modulating gibberellic acid ( ga ) signalling . in line with this report , jiang et al . , (
2007 ) showed that low pi in plants resulted in a reduction in bioactive ga levels and accumulation of della proteins .
worth noting that della - mediated signalling contributes only to certain aspects of pi - deficiency response in roots , typically are suppression of the primary root growth and promotion of root hairs .
the gaseous phytohormone , ethylene , has been shown to play an integral local role in the root hair formation , the lateral root elongation , and the reduction of primary root elongation upon pi starvation .
the root system of all ethylene mutants , such as the ethylene - insensitive mutants etr1 , ein2 , ein3 , and hls , the ethylene - overproducing mutant eto1 and the ethylene constitutive response mutant ctr1 , respond to pi deprivation by a decrease in primary root growth and an increase in lateral root formation , although the response of the ctr1 and eto1 mutants was reduced compared to wild type [ 8 , 13 ] .
some indication for the role of ethylene in systemic pi signalling through modulation a number of systemically controlled pi starvation responses start to emerge .
recently role of strigolactones ( sls ) in plant responses to pi growth conditions have been reported .
pi - deficiency has been shown to increase sls biosynthesis in arabidopsis roots and transport through the xylem to the shoot .
sls act as long - distance shoot - branching inhibitors [ 70 , 71 ] .
sls have also been suggested to have a positive effect on root - hair elongation , mediated via the max2 f - box .
the sls ' ability to regulate root development may be executed by induction of the ethylene pathway in conjunction with regulation of auxin transport [ 72 , 73 ] .
sls were suggested to negatively regulate lateral root ( lr ) formation in arabidopsis , under conditions of sufficient pi nutrition .
the brassinosteroid ( br ) signaling pathway regulates numerous physiological and developmental processes in plants . in roots ,
brs have both promoting and inhibitory effects on growth , depending on the intensity of the signal .
reported that two homologous br transcriptional effectors , namely brassinazole - resistant 1 ( bzr1 ) and brassinazole - resistant 2 ( bzr2 ) , block these responses ( namely exhaustion of the primary meristem , impaired unidirectional cell expansion and elevated density of lateral roots ) , consequently maintaining normal root development under low pi conditions .
the roots of the bzr1-d mutants remain longer at the very low pi concentration compared to wild type .
over the past few decades , many research works aimed to elucidate the molecular mechanisms controlling pi homeostasis in plants have been performed using arabidopsis thaliana as a model system .
a combination of genetics , molecular biology and genomics led to the identification and characterization of a number of genes that regulate growth and development of the root in arabidopsis in response to pi deficiency .
nevertheless , it is clear that much remains to be discovered to fully appreciate the molecular processes that govern the adaptation of plants root system to pi availability .
achieving this objective becomes possible thanks to the available resources in the current post - genomic era including completion of the arabidopsis genome , developing genome - wide profiling technology , the system biology methods and an arrays of experimental tools including phenotyping platforms .
orthologous of the arabidopsis regulatory genes in crop plants could be then targeted for biotechnological and agronomical applications .
Output:
| phosphorus ( p ) is an essential macronutrient for plant growth and development .
inorganic phosphate ( pi ) is the major form of p taken up from the soil by plant roots .
it is well established that under pi deficiency condition , plant roots undergo striking morphological changes ; mainly a reduction in primary root length while increase in lateral root length as well as root hair length and density .
this typical phenotypic change reflects complex interactions with other nutrients such as iron , and involves the activity of a large spectrum of plant hormones .
although , several key proteins involved in the regulation of root growth under pi - deficiency have been identified in arabidopsis , how plants adapt roots system architecture in response to pi availability remains an open question . in the current post - genomic era , state of the art technologies like high - throughput phenotyping and sequencing platforms,omics methods , together with the widespread use of system biology and genome - wide association studies
will help to elucidate the genetic architectures of root growth on different pi regimes .
it is clear that the large - scale characterization of molecular systems will improve our understanding of nutrient stress phenotype and biology .
herein , we summarize the recent advances and future directions towards a better understanding of arabidopsis root developmental programs functional under pi deficiency . such a progress is necessary to devise strategies to improve the pi use efficiency in plants that is an important issue for agriculture . |
PubmedSumm6541 | ***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: nebulizer solutions are widely used in the treatment of asthma and chronic obstructive pulmonary disease .
a number of bronchial and nasal nebulizer preparations contain benzalkonium chloride ( bac ) ( 1 ) .
quaternary ammonium compounds are used as antiseptics , disinfectants , detergents , and preservatives , and of these bac is the most frequently used .
we report a 23-yr - old woman presenting with anaphylactic shock following an intradermal skin test with a nebulizer solution containing bac . as far as we could ascetain from available literatures ,
this is the first reported case of anaphylaxis caused by benzalkonium in a nebulizer solution .
a 23-yr - old woman who had complained of exacerbation of cough and dyspnea after inhalation therapy with a nebulizer solution was referred to our outpatient clinic .
she had been diagnosed with asthma 3 yr previously and treated with a metered dose of a short - acting b2-agonist inhaler as needed .
she had no history of anaphylaxis , urticaria , or drug allergy . on admission ,
her white cell count was 7,400/l with 5% eosinophils and the serum total ige was 256 iu / ml by the eia method .
on spirometry , her forced vital capacity and forced expiratory volume in 1 sec were 3,520 ml ( 90% of the predicted value ) and 2,700 ml ( 86% of the predicted value ) , respectively .
she underwent skin prick tests with a panel of 10 common inhalant allergens and histamine ( allergopharma co. , hamburg , germany ) and serial dilution of nebulizer solution containing bac ( ventolin , glaxosmithklein , u.k . ) .
the skin prick test was positive only for house dust mites species ( dermatophagoides farinae and d. pteronyssinus ) .
subsequently , an intradermal skin test with a serial dilution of her nebulizer solution was performed .
a positive reaction was observed with 1:10 solution ( wheal : 45 mm in diameter , flare : 1820 mm ) .
her blood pressure was 70/30 mmhg , and her pulse was 120 - 140 per minute .
she was resuscitated with a subcutaneous injection of epinephrine ( 0.5 mg ) , an intravenous infusion of saline , and oxygen .
after obtaining oral informed consent , two healthy women without atopy or allergies underwent intradermal skin tests with the same nebulizer solution .
one month later , we conducted a bronchial provocation test with bac following the method used by asmus et al .
the patient inhaled 3 ml of 0.9% nacl solution containing 600 g of bac ( benzalkonium chloride , sigma , st .
the solutions were prepared using aseptic techniques and stored at 2 in an eppendorf tube .
each 3 ml dose was inhaled using normal tidal breathing through a devilbiss 646 nebulizer ( devilbiss co. , somerset , pa , u.s.a . ) .
spirometry was performed at the beginning of the test and 15 min after inhalation of each dose began . on bac bronchial challenge ,
the patient refused skin test with bac since she was aware of her anaphylactic reaction .
this patient 's history and the results of the skin test and bac bronchial provocation test are consistent with anaphylaxis caused by a nebulizer solution containing bac .
our case showed a positive skin test to nebulizer solution and developed an anaphylactic reaction .
although a positive bronchial provocative response to bac is not specific to diagnosis of bac - induced anaphylaxis , the immediate development of symptoms and bronchoconstriction in response to bac were significant in this case .
bac is one of the best known etiologic causes of contact dermatitis and occupational asthma .
it is found in cosmetics , soaps , baby lotions , body lotions , and skin care products , as well as in medical products , such as eye drops , ointments , and solutions .
some bronchial nebulizer solutions contain bac as a bactericidal preservative , and it causes paradoxical bronchoconstriction in some asthmatics when inhaled .
the mechanism of the allergic reaction caused by bac and other chemicals remains controversial ( 3 ) .
the previous reports on bac - induced asthma suggest that it induces anaphylaxis via either ige - mediated or non - ige mediated mechanisms .
our case showed a positive intradermal test , suggesting that an ige - mediated mechanism played a role in causing the reaction .
however , this does not exclude the possibility that bac also causes non - specific histamine release from mast cells via surface activation .
this is supported by previous reports of dose - dependant histamine release from rat mast cells , and antihistamine inhibition of the bronchoconstriction caused by bac ( 4 , 5 ) . in conclusion ,
our patient had an anaphylactic reaction caused by the intradermal injection of benzalkonium chloride in her nebulizer solution .
although this is not a common complication , such reactions may occur in patients treated with nebulized solutions containing bac .
Output:
| benzalkonium chloride ( bac ) is commonly used as a bactericidal preservative in nebulizer solutions , and can cause paradoxical onchoconstriction following nebulizing therapy in some asthmatics .
we describe a case of anaphylactic shock in a 23-yr - old asthmatic woman following an intradermal skin test with a salbutamol solution containing bac .
since she complained of cough and dyspnea after inhalation therapy with a nebulizer solution , we conducted an intradermal skin test using the same solution , which contained bac .
about 10 min later , the patient reported dizziness , palpitations , and dyspnea . on examination , tachycardia ,
tachypnea , and hypotension were found .
she was resuscitated with a subcutaneous injection of epinephrine and an infusion of saline .
one month later , we conducted a bronchial provocation test with bac , and she showed a positive response . |
PubmedSumm6542 | ***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: moyamoya disease ( mmd ) is a specific cerebrovascular disease affecting the termini of the internal carotid arteries , typically bilaterally9 ) .
thus , a natural approach is to investigate the vessel wall cells of mmd patients in search of significant findings that are relevant to mmd pathophysiology and treatment .
we propose that this research interest must be driven in two directions , endothelial - lineage cells and smooth muscle - type ( mural ) cells , as both cells are indispensable to completely healthy vasculature . in reality , it is not easy to obtain these cells directly from patients , except for tiny specimens that are obtained during direct bypass surgery and tissues from autopsy cases . therefore , vascular progenitor cells seem to be a valuable cell type for disease research because they can be derived from patient peripheral blood .
endothelial progenitor cells ( epcs ) have been an important topic in research evaluating several vascular diseases , including heart disease and ischemic cerebrovascular disease ; however , the concept of smooth muscle progenitor cells ( spcs ) has only recently been introduced . in this review
, we present the up - to - date accomplishments with regard to vascular progenitor cell studies in moyamoya disease .
circulating epcs originate from the bone marrow , and they seem to take part in both postnatal vasculogenesis and vascular homeostasis7 ) .
epcs are usually characterized by the surface protein expression of cd31 [ an endothelial cell marker , also known as pecam-1 ( platelet endothelial cell adhesion molecule-1 ) ] , cd34 ( a hematopoietic or progenitor marker ) , and vascular endothelial growth factor receptor-2 [ vegfr-2 , also known as kdr [ kinase insert domain receptor ) ] .
several investigators consider the stem cell marker cd133 to be a more precise epc marker .
cd133/cd34/vegfr-2 cells are considered to represent a more primitive epc type with high proliferative potential . in identifying epcs , the usefulness of other markers such as cd45 ( the leukocyte common antigen ) and cd14 ( a myelomonocytic cell marker ) is controversial3 ) .
the expression of von willebrand factor , uptake of acetylated low - density lipoprotein , and enhanced endothelial nitric oxide synthase expression after shear - stress exposure can also be demonstrated14 ) .
functionally , epcs exhibit tremendous proliferative capacity and can be mobilized to vasculogenesis sites1 ) .
spcs from human peripheral blood were first isolated and cultured by simper et al.12 ) in platelet - derived growth factor ( pdgf ) bb - enriched media .
spc - type outgrowth cells show a " hill - and - valley " appearance , while epc - type outgrowth cells show a " cobblestone " appearance ( fig . 1)1214 ) .
in addition to the striking morphological differences in the outgrowth cells , they are characterized by positive staining with smooth muscle actin- , smooth muscle myosin heavy chain ( mhc ) and calponin , which are smooth muscle - specific . in a previous experiment , these cells had 4- to 5-fold greater proliferative potential compared with endothelial outgrowth cells12 ) . for epc culture from peripheral blood ,
the cells are plated in culture dishes that are coated with fibronectin and are cultured in endothelial cell growth medium that is enriched with vascular endothelial growth factor ( vegf ) .
for spc cultures , pdgf bb - enriched media seems to be essential . in a previous experiment ,
pdgf - bb was added at a concentration of 5 ng / ml since the seventh day of culturing6 ) .
two studies present opposing opinions on the relation between epc circulation and moyamoya disease810 ) .
rafat et al.10 ) demonstrated increased circulating hematopoietic stem cell and epc levels ( healthy controls vs. moyamoya disease subjects , 0.09% vs. 0.29% for cd34cd133 cells ; 0.02% vs. 0.11% for cd34cd133vegfr-2 cells ) from an adult moyamoya disease population ( mean age , 35.715.9 years ) .
in contrast , kim et al.8 ) studied circulating epcs from a pediatric moyamoya disease population ( mean age , 7.5 years ; age range , 2 - 13 years ) . on the day when the blood was collected ( day 0 ) , kim et al.8 ) showed that the percentages of circulating cells that were positive for cd34 , cd133 , and kdr were significantly lower in the study subject population ( normal controls vs. subjects , 8.48% vs. 2.97% for cd34 ; 0.56% vs. 0.09% for cd133 ; and 8.40% vs. 1.04% for kdr ; all p less than 0.05 ) .
rafat et al.10 ) presented data regarding double ( cd34cd133 cells ) and triple positive cells ( cd34cd133vegfr-2 cells ) , while kim et al.8 ) provided the numbers of cells that were positive for the respective markers .
thus , the differences in the datasets and ages of the study subjects make direct comparison of the two studies difficult .
we acknowledge that the cd133 cells made up less than 1% of the peripheral blood mononuclear cells in both studies . in general , there are more driving cues for vascular progenitor cell recruitment in patients with ischemic cerebrovascular diseases . failure to show such an adequate response might be responsible for early and severe manifestations in pediatric mmd patients .
jung et al.5 ) compared the numbers of colony - forming units ( cfu , also called as ' cell clusters ' ) of epcs and outgrowth cells between mmd patients and healthy controls , and they demonstrated that the cfu numbers decreased ( mmd patients vs. controls , 32.426.7 vs. 65.218.3 , p<0.001 ) and the outgrowth cells were more frequently isolated in the mmd patients ( 33.3% vs. 10.4% , p=0.025 ) .
notably , the outgrowth cells were isolated in all patients ( n=3 ) who underwent revascularization surgery .
additionally , they found that low epc - cfu number ( less than 30 ) was more prevalent in the patients with more advanced mmd ( p=0.001 ) .
they also showed that conditioned media from epcs of mmd patients significantly induced less tube formation , which reflected impaired paracrine function in the patients ' epcs .
three - day cultures of mononuclear cells were used to produce the conditioned media , and human umbilical vein endothelial cells were employed for the tubule formation assay .
pediatric mmd patients also showed reduced epc cell cluster formation8 ) . from a different perspective ,
kim et al.8 ) conducted a tubule formation assay with late epcs ( i.e. , cells with cobblestone morphology ) from mmd patients and normal controls , and they showed that the patient cells had reduced tubule formation capability .
a senescence - associated -galactosidase assay revealed a higher percentage of senescent cells among the epcs from the patients .
recently , cells expressing cd34 and vegfr2 were found in the thickened intima of supraclinoid internal carotid arteries that were collected from adult mmd patients13 ) .
these findings suggest that bone marrow - derived circulating epcs may participate in development of the occlusive arterial lesions in mmd .
the origin of the smooth muscle cells is one of the key questions regarding mmd pathophysiology .
we established spcs from the peripheral blood of mmd patients6 ) . for cell culture , well plates that were coated with type i collagen were used .
after 5 days , non - adherent cells were removed , and fresh culture medium was applied . at 1 week , pdgf - bb was added to the culture medium .
after the initial cell cluster formation , two patterns of outgrowth cells appeared , which included spcs ( hill - and - valley pattern ) and epcs ( cobblestone appearance ) .
fluorescence - activated cell sorter ( facs ) analysis demonstrated that spcs were present in 20% of the observed mmd patients , epcs were present in 68% of the patients , and a mixed pattern was observed in 12% of the patients . among the normal controls ,
facs analysis revealed that spcs were present in 30% , epcs were present in 40% , and a mixed population was present in 40% of the subjects
spcs from the patients had lower pdgf receptor expression ( mmd patients vs. controls , 38.5%2.6% vs. 66.1%8.2% , p=0.0286)6 ) .
pdgf receptor expression was not significantly different between the groups ( 87.73.1% vs. 96.61.2% , p= 0.1143 ) .
spcs from the patients also had lower mhc ( 42.818.6% vs. 961.8% ; p=0.0087 ) and calponin expression levels ( 87.1 8.2% vs. 99.80.1% ; p=0.0519 ) .
it was presumed that a defect in the cell maturation process might have occurred in the spcs from the mmd patients .
interestingly , the tubule formation assay identified more irregularly arranged and thickened tubules with the patient spcs , which is reminiscent of the pathologic findings of the mmd patient cerebral arteries ( fig .
an affymetrix gene chip mrna microarray revealed 286 differentially expressed genes in spcs from mmd patients with a > 1.5-fold change and a t - test p value<0.016 ) .
gene ontology ( go ) analysis for the 124 up - regulated transcripts identified 19 terms ( p<0.05 ) , which included responses to endogenous stimulus , anterior / posterior pattern formation , and ephrin receptor signaling .
meanwhile , the go analysis for the 162 down - regulated transcripts identified 26 terms ( p<0.01 ) , including cell adhesion , cell migration regulation , innate immune response , enzyme - linked receptor protein signaling pathways , and vasculature development .
it is known that circulating epc number increases significantly after various injury types , including myocardial infarction , coronary artery bypass grafting , and stroke2411 ) .
studies evaluating epcs from mmd patients showed differences in epc mobilization between adult and pediatric patients810 ) , which might explain differences in the disease presentation and severity between the two age groups .
additionally , epcs from mmd patients were found to be functionally impaired , whereby they failed to form tubules and showed defects in paracrine functions510 ) .
further studies are under way to define the specific causes and possible solutions for these functional impairments .
it can be hypothesized that the thickened intima in mmd patients ' cerebral arteries may ( at least partly ) result from malfunctioning epcs and spcs during the vascular repair and maintenance process .
although studies on spcs are scarce , a study revealed some distinctive characteristics in relation to the cell culture finding , immaturity in terms of expression markers , defective tubule formation , and differential gene expression that were relevant to vascular development .
further studies are required to specify these characteristics in the setting of disease pathogenesis . moreover , in vivo studies and animal models that mimic the disease are also required .
still , there is much to learn in regard to mmd and vascular progenitor cells .
thus , research that utilizes these particular cells seems to be promising , although the establishment and maintenance of progenitor cells requires significant manpower , facilities , and funds .
Output:
| various approaches have been attempted in translational moyamoya disease research . one promising material for modeling and treating this disease is vascular progenitor cells , which can be acquired and expanded from patient peripheral blood .
these cells may provide a novel experimental model and enable us to obtain insights regarding moyamoya disease pathogenesis .
we briefly present the recent accomplishments in regard to the studies of vascular progenitor cells in moyamoya disease . |
PubmedSumm6543 | ***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:
| dna adducts derived from complex mixtures of polycyclic aromatic compounds emitted from tobacco smoke are compared to industrial pollution sources ( e.g. , coke ovens and aluminum smelters ) , smoky coal burning , and urban air pollution .
exposures to coke oven emissions and smoky coal , both potent rodent skin tumor initiators and lung carcinogens in humans , result in high levels of dna adducts compared to tobacco smoke in the in vitro calf thymus dna model system , in cultured lymphocytes , and in the mouse skin assay .
using tobacco smoke as a model in human studies , we have compared relative dna adduct levels detected in blood lymphocytes , placental tissue , bronchoalveolar lung lavage cells , sperm , and autopsy tissues of smokers and nonsmokers .
adduct levels in dna isolated from smokers were highest in human heart and lung tissue with smaller but detectable differences in placental tissue and lung lavage cells .
comparison of the dna adduct levels resulting from human exposure to different complex mixtures shows that emissions from coke ovens , aluminum smelters , and smoky coal result in higher dna adduct levels than tobacco smoke exposure .
these studies suggest that humans exposed to complex combustion mixtures will have higher dna adduct levels in target cells ( e.g. , lung ) as compared to nontarget cells ( e.g. , lymphocytes ) and that the adduct levels will be dependent on the genotoxic and dna adduct - forming potency of the mixture .
imagesfigure 1.figure 1.figure 2.figure 3.figure 3.figure 3.figure 3.figure 3.figure 3.figure 4 . |
PubmedSumm6544 | ***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: hepatitis c virus ( hcv ) is a major cause of post transfusion hepatitis and liver transplantation in many countries .
it is estimated that approximately 3% of the world 's population is infected with hcv and 60% to 85% of the patients develop chronic infection that leads to cirrhosis , and hepatocellular carcinoma , and need liver transplantation ( 1 , 2 ) .
three groups of hcv testing are available : 1 ) serological assays to detect anti - hcv .
hcv tests are used to diagnose hcv and to guide therapy and/or monitor the treatment of hcv infection ( 1 , 3 - 5 ) . the most common type of hcv antibody testing is the enzyme immunoassay by methods of enzyme linked immunosorbent assay ( elisa ) , and chemiluminescence immunoassay ( cia ) .
elisa testing is a semi - quantitative assay that its results are reported as positive or negative based on comparison of absorbance reading of each sample with a cut - off value defined for the lot used expressed as a signal to cutoff ratio ( s / co ) , and shows the quantity of antibody in blood ( 6 ) . although hcv antibody assays are highly sensitive and specific in patients with chronic hcv infection , there are frequent false positive in anti - hcv results .
quantitative viral load tests are used to measure the amount of hcv - rna in one milliliter of blood .
pcr - based hcv rna methods are used as the gold standard to confirm the hcv positivity in anti - hcv assays and monitor the treatment ( 1 , 4 , 7 - 9 ) .
the current study aimed to evaluate the relationship between quantitative anti - hcv ( s / co ratio ) and quantitative hcv - rna levels , also to determine a specific s / co ratio with a routine commercial hcv - ab kit used in the laboratories to identify viremic from non - viremic anti - hcv positive patients .
in the current cross sectional study , from may 2012 to october 2013 , 378 patients suspected with hcv who referred to iranian blood transfusion organization ( ibto ) research center were included .
patients had no history of hepatitis b virus ( hbv ) and human immunodeficiency virus ( hiv ) infections .
the written consent was signed by the patients to include in the study and the questioner was filled out for all subjects .
all subjects also were tested for anti - hcv assay ; hcv viral loads were performed on all anti - hcv positive patients .
all fresh serum samples were assayed for anti - hcv ( hepanostika hcv ultra , uk ) by elisa method , according to the manufacturer 's protocol .
the results were expressed as s / co ratio calculated by dividing the signal detected on each sample to the cut - off value .
briefly , viral rna was extracted from one milliliter plasma using the qiaamp ultrasense virus kit ( qiagen , germany ) according to the manufacturer 's protocol .
the extracted rna was eluted in elution buffer and used as the template for the quantitative rna pcr .
quantitative rna pcr was performed using artus hcv rg rt- pcr kit ( qiagen gmbh , qiagen strasse , germany ) with lower detection limit of 34 iu / ml .
20 l of the extracted rna was added to 30 l of master mix in each 0.1 ml microtube and test was performed in rotorgene - q apparatus .
a standard curve was automatically drawn with the rotorgene - q software using five quantification standard concentrations of hcv - rna to analyze the viral rna load .
the results expressed in iu/l were determined in iu / ml based on artus hcv rg rt- pcr kit handbook . in each run , plasma negative sample and internal control were used to prevent false positive and negative results , respectively .
quantitative group variables were described as mean , standard deviation , and range . to compare variables ,
in the current cross sectional study , from may 2012 to october 2013 , 378 patients suspected with hcv who referred to iranian blood transfusion organization ( ibto ) research center were included .
patients had no history of hepatitis b virus ( hbv ) and human immunodeficiency virus ( hiv ) infections .
the written consent was signed by the patients to include in the study and the questioner was filled out for all subjects .
all subjects also were tested for anti - hcv assay ; hcv viral loads were performed on all anti - hcv positive patients .
all fresh serum samples were assayed for anti - hcv ( hepanostika hcv ultra , uk ) by elisa method , according to the manufacturer 's protocol .
the results were expressed as s / co ratio calculated by dividing the signal detected on each sample to the cut - off value .
briefly , viral rna was extracted from one milliliter plasma using the qiaamp ultrasense virus kit ( qiagen , germany ) according to the manufacturer 's protocol .
the extracted rna was eluted in elution buffer and used as the template for the quantitative rna pcr .
quantitative rna pcr was performed using artus hcv rg rt- pcr kit ( qiagen gmbh , qiagen strasse , germany ) with lower detection limit of 34 iu / ml .
20 l of the extracted rna was added to 30 l of master mix in each 0.1 ml microtube and test was performed in rotorgene - q apparatus .
a standard curve was automatically drawn with the rotorgene - q software using five quantification standard concentrations of hcv - rna to analyze the viral rna load .
the results expressed in iu/l were determined in iu / ml based on artus hcv rg rt- pcr kit handbook . in each run , plasma negative sample and internal control were used to prevent false positive and negative results , respectively .
quantitative group variables were described as mean , standard deviation , and range . to compare variables ,
of the 265 hcv - ab positive patients , 204 ( 77% ) were male and the mean age was 43.53 13.17 years .
there were significant differences in s / co ratio between viremic and non - viremic patients .
the s / co ratio was higher in viremic group than the non - viremic group ( p < 0.05 ) ( table 1 ) .
( % ) or mean sd . the sensitivity , specificity , negative predictive and positive predictive values were 100% , 81.4% , 100% , and 77.2% , respectively in the s / co ratio of 2.7 ( table 2 ) .
all of the data are presented as ( % ) except anti - hcv s / co ratio .
it is estimated that 20% of people with chronic hcv infection develop cirrhosis after 25 years ( 1 , 4 , 8 - 10 ) .
a positive result of anti - hcv by elisa method may represent active viremia , infection in the past or false positive .
although recombinant immunoblot assay ( riba ) is used to confirm results in elisa method , it can not detect viremia to follow treatment .
qualitative and quantitative assays for hcv - rna are introduced as gold standards to confirm viremia in patients with positive anti - hcv ( 1 , 4 , 8 , 9).quantification of hcv - rna is important to determine disease status and is used before and during anti - viral therapy ( 9 - 14 ) .
although using quantitative hcv - rna rt - pcr to detect and monitor the treatment of hcv infection is approved , it consumes time and money especially in patients with no viremia ; also , its high cost makes it unavailable in many laboratories .
recently , the necessity to use confirmatory testing in anti - hcv low s / co ratio was suggested by the centers for disease control ( cdc ) .
they also introduced s / co ratio 3.8 as a cut - off value and suggested that s / co ratio < 3.8 determines low positive .
an anti - hcv s / co ratio 3.8 determines a true anti - hcv positive result in 95% of cases .
in contrast , in patients with s / co ratio 3.8 the mentioned possibility is high ( 15 ) .
several studies conducted to detect a cut - off point to distinguish low positive from high positive subjects reported that the majority of subjects with low positive anti - hcv results , by elisa method , were negative in hcv - rna testing ( 6 , 12 , 13 ) .
several studies are conducted to introduce s / co value to distinguish viremic and non - viremic patients . in several published studies ,
different s / co values ranging from 3 to 34 were determined in the third generation of anti - hcv assays ( 6 , 10 , 13 , 16 - 20 ) .
the result of the current study showed that in low positive anti - hcv elisa results , the frequency of false positivity was high . according to the obtained result , using 2.7 as a cut - off for s / co ratio , the sensitivity was 100% .
the study found that all hcv - ab positive patients with s / co cutoff ratio < 2.7 were not detectable hcv - rna .
positive results in hcv - ab assay may represent a past infection or false positive result .
in the current study the majority of the patients with hcv - ab positive , s / co cut - off ratio 2.7 were viremic .
due to differences in sample size , the study population , and the kit used to detect hcv - rna , there are discrepancies in the s / co ratios introduced as cut - off point in different studies . further studies with common approaches are necessary to predict using anti - hcv s / co ratio as a cut - off value . in conclusion
the present study indicated that anti - hcv s / co ratio can be used as a useful tool to manage hcv infection .
a cut - off value of 2.7 can determine the need to hcv - rna testing .
therefore , for patients with s / co < 2.7 , hcv - rna viral load is not recommended .
it is suggested that laboratories should report s / co ratio along with anti - hcv results .
Output:
| background : hepatitis c virus ( hcv ) infection is diagnosed by antibody and rna based methods .
patients with anti - hcv sample rate / cutoff rate ( s / co ) ratios > 1 are reported as anti - hcv positive .
rna based methods are introduced to confirm positivity in seropositive samples.objectives:the current study aimed to assess relationship between s / co rates and hcv - rna levels in the laboratory to identify hcv viremia in patients with a positive anti-hcv.patients and methods : all serum samples were assayed for anti - hcv by elisa method .
a total of 265 anti - hcv positive patients were tested for hcv - rna testing by quantitative method using artus hcv rg real - time polymerase chain reaction ( rt- pcr ) kit .
statistical analysis was done by spss version 16.results:of the 265 patients with hcv infection , 204 ( 77% ) were male and the mean age was 43.53 13.17 years , ranging 1 - 81 years .
no correlation was found between s / co ratios and hcv - rna levels
. there was significant difference in s / co ratio between viremic and non - viremic subjects .
the sensitivity , specificity , negative predictive value , and positive predictive value were 100% , 81.4% , 100% , and 77.2% , respectively in the s / co ratio of 2.7.conclusions:the present study indicated that anti - hcv s / co ratio is useful to predict non - viremic patients .
a cut - off value of 2.7 can determine the usefulness of hcv - rna testing .
patients with s / co < 2.7 are not viremic ; therefore , hcv - rna testing is not recommended .
it is suggested that laboratories report s / co ratio along with anti - hcv results to manage hcv infection better , especially in countries that quantitative hcv testing is expensive or not available . |
PubmedSumm6545 | ***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: laminectomy without reconstruction has been the standard surgical treatment method for intradural and posterior epidural spinal lesions7 ) .
although this surgical technique provides an adequate operative field , it may lead to hematoma in the spinal canal , invasion of scar tissue after surgery , or postoperative instability and scoliosis45 ) . as microscopic surgical techniques have evolved ,
new surgical methods such as laminoplasty with the use of a t - saw for reconstruction36 ) or laminoplasty with a 90 or 60 change in the lamina with en bloc removal14 ) have been introduced .
some authors have reported that certain spinal cord tumors can be removed through hemilaminectomy and a minimally invasive technique that involves the use of a tubular retractor system , which enables maximum preservation of the posterior elements210 ) . here ,
we report a spinous process - splitting hemilaminoplasty technique that maintains the shape and integrity of the posterior elements and retains a barrier that prevents hematoma in the spinal canal and scar tissue damage .
between 2011 and 2014 , spinous process - splitting hemilaminoplasty was performed in nine patients .
physical examinations , mri with gadolinium , ct , and routine radiography with dynamic imaging of the intradural and posterior epidural lesions were performed prior to surgery .
unilateral paravertebral muscle dissection reveals the lamina and a part of the medial facet joint .
a hole is created in the spinous process , lamina , and medial articular facet with a match head burr ( 1.7 mm ) drill to achieve laminoplasty to replace the bone that was removed en bloc into the exact pre - surgery position .
the splitting of the spinous process can be performed by 1 ) cutting to a depth determined on the basis of measurements on computed tomography ( ct ) scans with an oscillating saw in the midline where the epidural space is wide or 2 ) splitting with the t - saw by partially removing the surrounding ligament flavum to facilitate use of the t - saw , revealing the dura and enabling passage of the t - saw stylet . in the cases reported here
, we used both methods and found that the t - saw method resulted in less bone loss due to the cutting . using a fine burr ,
we linearly drilled the laminofacet junction into the spinal canal in order to perform the hemilaminectomy .
this approach secures a wider operating field than previous hemilaminectomy procedures , as the surgeon is able to see as much as half of the spinous process .
furthermore , undercutting of the opposite side of the spinolamina junction enables the surgeon to see the dura margin on the contralateral side , providing enough space to treat intradural and posterior epidural lesions .
finally , the 1-cm operating field is wide enough to place dura sutures . after removing the spinal lesion
, we performed suture for the spinous process and the laminofacet junction , which enabled laminoplasty with similar pre - surgery integrity . of note , placing the sutures on the split spinous process results in a stable suture on the laminofacet junction without subsequent movement .
non - absorbable suture threads were used to stabilize the surgical area and to prevent the formation of artifacts .
this is beneficial given that imaging techniques such as magnetic resonance imaging ( mri ) are used for follow - up inspection .
surgical outcomes were evaluated on the basis of postoperative symptom states and complications , operation time , and estimated blood loss ( ebl ) ( table 2 ) .
between 2011 and 2014 , spinous process - splitting hemilaminoplasty was performed in nine patients .
physical examinations , mri with gadolinium , ct , and routine radiography with dynamic imaging of the intradural and posterior epidural lesions were performed prior to surgery .
unilateral paravertebral muscle dissection reveals the lamina and a part of the medial facet joint .
a hole is created in the spinous process , lamina , and medial articular facet with a match head burr ( 1.7 mm ) drill to achieve laminoplasty to replace the bone that was removed en bloc into the exact pre - surgery position .
the splitting of the spinous process can be performed by 1 ) cutting to a depth determined on the basis of measurements on computed tomography ( ct ) scans with an oscillating saw in the midline where the epidural space is wide or 2 ) splitting with the t - saw by partially removing the surrounding ligament flavum to facilitate use of the t - saw , revealing the dura and enabling passage of the t - saw stylet . in the cases reported here , we used both methods and found that the t - saw method resulted in less bone loss due to the cutting . using a fine burr , we linearly drilled the laminofacet junction into the spinal canal in order to perform the hemilaminectomy .
this approach secures a wider operating field than previous hemilaminectomy procedures , as the surgeon is able to see as much as half of the spinous process .
furthermore , undercutting of the opposite side of the spinolamina junction enables the surgeon to see the dura margin on the contralateral side , providing enough space to treat intradural and posterior epidural lesions .
finally , the 1-cm operating field is wide enough to place dura sutures . after removing the spinal lesion
, we performed suture for the spinous process and the laminofacet junction , which enabled laminoplasty with similar pre - surgery integrity . of note , placing the sutures on the split spinous process results in a stable suture on the laminofacet junction without subsequent movement .
non - absorbable suture threads were used to stabilize the surgical area and to prevent the formation of artifacts .
this is beneficial given that imaging techniques such as magnetic resonance imaging ( mri ) are used for follow - up inspection .
surgical outcomes were evaluated on the basis of postoperative symptom states and complications , operation time , and estimated blood loss ( ebl ) ( table 2 ) .
the age of the patients ranged from 28 to 76 years ( mean , 60.2 years ) .
eight had an intradural extramedullary spinal tumor and one had ossification of the ligament flavum .
the surgical sites were cervical in six patients , thoracic in one , and lumbar in two ( table 1 ) .
spinous process - splitting hemilaminoplasty was performed on levels 1 - 3 with a mean operation time of 237.847.0 min ( range , 160 - 315 min ) and a mean ebl of 116.761.2 ml ( range , 50 - 200 ml ) .
post - surgical diagnoses were schwannoma in five patients , meningioma in two , neurofibroma in one , and ossification of the ligament flavum in one .
we performed total resection in the schwannoma , neurofibroma , and ossified ligament flavum cases , and simpson grade ii resection in the patients with meningioma ( table 2 ) .
the postoperative follow - up period was 6 to 31 months , and all patients were able to walk 1 day after surgery .
ct scans were obtained for each patient 6 months after surgery , and the findings confirmed that laminoplasty was achieved on the bone fusion without displacement .
a 57-year - old female patient had pain and numbness in her left arm for 3 months .
cervical mri revealed an intradural extramedullary spinal tumor leaning toward the left at c3 - 4 - 5 ( fig .
we split the spinous process on the left side of c3 - 4 - 5 , drilled the facet lamina junction , and performed en bloc hemilaminectomy . after removing the tumor
, we placed the detached bone fragments in their original position using non - absorbable suture threads ( fig . 2c ) .
ct performed 6 months after surgery revealed that bone fusion had been achieved ( fig .
3a , b ) , and a spinous - splitting hemilaminectomy was performed . to achieve optimal vision , undercutting of the contralateral spinous process was performed , which enabled the surgeon to see both sides of the dura to the same extent ( fig .
a 62-year - old female patient had progressive pain and numbness in the right arm 3 months prior to her hospital visit .
mri revealed an intradural extramedullary spinal tumor on the right side of c5 - 6 ( fig .
spinous process - splitting hemilaminectomy was performed on the right side of c5 - 6 , and the tumor was removed .
laminoplasty was performed in the same position , using non - absorbable threads ( fig .
a 57-year - old female patient had pain and numbness in her left arm for 3 months .
cervical mri revealed an intradural extramedullary spinal tumor leaning toward the left at c3 - 4 - 5 ( fig .
we split the spinous process on the left side of c3 - 4 - 5 , drilled the facet lamina junction , and performed en bloc hemilaminectomy . after removing the tumor
, we placed the detached bone fragments in their original position using non - absorbable suture threads ( fig . 2c ) .
ct performed 6 months after surgery revealed that bone fusion had been achieved ( fig .
3a , b ) , and a spinous - splitting hemilaminectomy was performed . to achieve optimal vision , undercutting of the contralateral spinous process was performed , which enabled the surgeon to see both sides of the dura to the same extent ( fig .
a 62-year - old female patient had progressive pain and numbness in the right arm 3 months prior to her hospital visit .
mri revealed an intradural extramedullary spinal tumor on the right side of c5 - 6 ( fig .
spinous process - splitting hemilaminectomy was performed on the right side of c5 - 6 , and the tumor was removed .
laminoplasty was performed in the same position , using non - absorbable threads ( fig .
although laminectomy has previously been used to treat intradural lesions , the surgical outcomes have often been compromised by hematoma , scar tissue invasion , and/or postoperative instability . with
asazuma et al.1 ) performed 90 degree - rotation laminoplasty on spinal cord and cauda equina tumors in seven patients and reconstructed the vertebral arch .
the authors reported satisfactory operative exposure , a maintained range of motion , and an improved japanese orthopedic association score .
hida et al.4 ) introduced a 60 degree - rotation laminoplasty with titanium mini - plates .
of the eight patients who underwent surgery , six had an intradural tumor as well as ossification of the ligament flava and spontaneous spinal cord herniation .
this can only be conducted on the thoracic and lumbar spine where the spinous process is long , but not on the cervical spine where the spinous process is short .
therefore , these techniques can only be used to treat thoracic and lumbar lesions . furthermore , because bone fusion does not mirror the original state , this technique can not be considered true reconstructive laminoplasty .
in contrast , the method that we introduced here involves minimizing bone loss by cutting the spinous process with a t - saw or oscillating saw to obtain a wide epidural space , enabling preservation of the pre - surgical appearance .
this technique is not only applicable to the thoracic and lumbar spine regions , but also to cervical lesions .
in addition , because it does not involve the use of titanium mini - plates , there are no artifacts , and therefore , imaging evaluations are more accurate , especially in cases of tumors that could be recurrent .
hemilaminectomy has been introduced as a surgical treatment for intradural lesions using a unilateral approach28 ) .
it preserves the contralateral muscles and ligaments , which prevents secondary instability and scoliosis after laminectomy .
however , in hemilaminectomy , the lamina is removed via a unilateral approach , and thus , the operative field is restricted .
in contrast , our technique involves splitting the spinous process , thereby allowing the midline of the dura to be seen ( fig .
3 ) . undercutting of the spinous process enables the surgeon to see around the midline of the dura and dura margins , and therefore , both sides become visible .
hara et al.3 ) performed en bloc laminoplasty on 16 patients using a t - saw , and similar to the results obtained using our technique , the bone shape remained similar before and after surgery .
the authors reported that by cutting the spinous process around the surgical level and placing the sutures , they were able to preserve posterior supporting elements such as the supraspinous and infraspinous ligaments , preventing kyphotic deformity after laminoplasty .
however , our method involves a smaller incision because the spinous process around the surgical area is not removed .
moreover , the midline and contralateral posterior elements remain intact , and thus , the physiological integrity of the spinous ligament is maintained while postoperative kyphotic deformity is prevented .
it should also be noted that splitting the spinous process where there is a large amount of cancellous bone , rather than the laminofacet junction , results in better bone fusion .
spinous process - splitting hemilaminoplasty and other surgical methods were compared with respect to operative time and blood loss12348 ) .
the operation time for 60-degree rotation laminoplasty3 ) was 233.7563.46 min ( 170 - 380 ) and blood loss was 218.75176.33 ml ( 45 - 600 ) , while for 90-degree rotation laminoplasty1 ) , the operation time was 338.29144.35 min ( 205 - 445 ) and blood loss was 578.43176.33 ml ( 73 - 2038 ) . for heminlaminectomy8 ) , operative time was 246.6761.54 min ( 180 - 320 ) and blood loss during surgery was 55.8312.01 ml . for en - bloc laminoplasty3 ) , surgery time was 350.6381.20 min ( 242 - 485 ) and blood loss was 589.31282.89 ml ( 90 - 1209 ) .
these results are similar to those obtained using our surgical technique . and the minimal operative time and bleeding on our surgical method were similar for other surgical methods .
the majority of spinal tumors are either intradural extramedullary ( 40% ) or extradural ( 55% ) tumors , and the intradural lesions often lean toward one side8 ) . in our cases , during same period , we treated a total of 11 cases of spinal cord tumors .
except for two patients with intradural intramedullary tumors and one patient with previous posterior spine surgery , spinous process - splitting hemilaminoplasty was performed in all cases where conventional techniques were applicable .
our novel surgical technique has advantages over previous laminectomy , laminoplasty , and hemilaminectomy techniques .
primarily , this new procedure enables adequate visualization during surgery and prevents scar tissue invasion and hematoma .
moreover , it does not cause injury to the muscles and ligaments on the contralateral side of the lesion , and thus prevents postoperative instability and subluxation .
finally , it should be noted that no imaging artifacts are produced as a result of the surgery , and therefore , imaging evaluations related to tumor recurrence are more accurate .
spinous process - splitting hemilaminoplasty for intradural and posterior epidural lesions preserves the contralateral posterior elements and maintains stability compared to previous reconstructive laminoplasty techniques .
visualization is also improved compared to previous hemilaminectomy techniques , and laminoplasty following this procedure helps maintain physiological integrity .
Output:
| objectiveto describe a novel spinous process - splitting hemilaminoplasty technique for the surgical treatment of intradural and posterior epidural lesions that promotes physiological restoration.methodsthe spinous process was split , the area of the facet lamina junction was drilled , and en bloc hemilaminectomy was then performed . after removing intradural and posterior epidural lesions , we fitted the previously en bloc - removed bone to the pre - surgery same shape , and held it in place with non - absorbable sutures .
surgery was performed on 16 laminas from a total of nine patients between 2011 and 2014 .
bony union of the reconstructed lamina was assessed using computed tomography ( ct ) at 6 months after surgery.resultsspinous process - slitting hemilaminoplasty was performed for intradural extramedullary tumors in eight patients and for ossification of the ligament flavum in one patient . because we were able to visualize the margin of the ipsilateral and contralateral dura
, we were able to secure space for removal of the lesion and closure of the dura .
none of the cases showed spinal deformity or other complications .
bone fusion and maintenance of the spinal canal were found to be perfect on ct scans.conclusionthe spinous process - splitting hemilaminoplasty technique presented here was successful in creating sufficient space to remove intradural and posterior epidural lesions and to close the dura .
furthermore , we were able to maintain the physiological barrier and integrity after surgery because the posterior musculature and bone structures were restored . |
PubmedSumm6546 | ***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: erythropoietin ( epo ) is a 34 kda glycoprotein hormone that controls the proliferation , differentiation , and survival of erythroid progenitor cells through an antiapoptotic mechanism .
it has become apparent that epo protects many organs , including brain , heart , kidney and liver , against the injury caused by ischaemia / reperfusion , hemorrhagic shock and systemic inflammation . in this issue of critical care , kao and colleagues
they found that recombinant human epo ( 400 iu / kg ) exerts significant beneficial effects when it is given as late as 18 hours after caecal ligation and puncture ( clp ) .
although epo had no effect on the ( small ) decline in blood pressure , the decline in platelet and white blood cell counts , or the rise in lactate , it significantly increased tissue perfusion and reduced tissue hypoxia . within 18 hours after clp there was a decline in the number of perfused capillary beds ( reduced oxygen delivery ) ; this , in turn , resulted in an impairment in mitochondrial electron transport and hence respiration ( measured as increase in mitochondrial nadh fluorescence ) in skeletal musle ( extensor digitorum longus ) .
most notably , epo rapidly ( within 10 min ) reversed both of these effects of clp , and hence it increased the number of patent capillaries and increased mitochondrial function .
unfortunately , the authors did not measure any parameters of organ injury and dysfunction , and the model of clp used did not ( within 24 hours ) result in any deaths .
thus , it remains to be seen whether the improvement in oxygen delivery or mitochondrial function afforded by epo also results in a significant improvement in outcome .
the study by kao and coworkers is of particular importance because epo protects the brain , heart , kidney and liver against the tissue injury and dysfunction caused by ischaemia / reperfusion ( for review ) .
the pathophysiology of the shock associated with trauma / haemorrhage also comprises elements of ischaemia / reperfusion injury ( because of hypovolaemia and resuscitation ) as well as excessive inflammation . in 2004
, we reported that administration of epo ( 300 iu / kg intravenously ) upon resuscitation reduced the renal dysfunction and liver injury caused by severe haemorrhage and resuscitation in rat .
these beneficial effects of epo were associated with a reduction in tissue ( renal ) apoptosis secondary to prevention of activation of caspase-3 , -8 and -9 .
interestingly , epo also prevents motor neurone apoptosis and associated neurological disability in an experimental model of spinal cord injury .
low doses of epo ( 300 iu / kg intravenously ) did not affect the organ injury / dysfunction caused by high doses ( 6 mg / kg ) of the toll - like receptor-4 agonist lipopolysaccharide ( lps ) within 6 hours in the rat . however , higher doses of epo ( 4,000 iu / kg given 30 min before lps ) attenuated the renal dysfunction ( decline in glomerular filtration rate ) , which occurred at 16 hours after injection of low - dose lps ( 2.5 mg / kg intraperitoneally ) in mouse .
this beneficial effect of epo in murine endotoxaemia was not due to effects of epo on either renal blood flow or apoptosis , but it was associated with prevention by epo of a fall in renal tissue superoxide dismutase activity associated with endotoxaemia .
thus , mitra and coworkers concluded that the observed beneficial effects of epo in murine endotoxaemia are secondary to both antioxidant and anti - inflammatory effects of epo , which have been reported in other models of disease .
thus , the beneficial effects of epo in rodent models of endotoxaemia may vary with doses of epo and lps , as well as species ( rat or mouse ) used .
interestingly , higher doses of epo reduce both the systemic inflammation and the organ injury caused by the toll - like receptor-2 agonist zymosan in mouse . specifically , treatment of mice with epo ( 1,000 iu / kg subcutaneously , 1 and 6 hours after zymosan ) attenuated the signs of local ( peritoneal exudation ) and systemic ( lung inflammation ) , as well as organ ( lung , liver and pancreas ) injury and dysfunction ( kidney ) caused by zymosan .
most notably , epo reduced the high mortality ( 70% ) caused by zymosan over the observation period of 7 days .
the reported beneficial effects of epo in preclinical models of shock , trauma and haemorrhage are exciting , but further studies are warranted to determine the effects of epo on outcome ( organ injury / dysfunction and survival ) in models of clp .
interestingly , in 86 patients admitted to a long - term acute care facility , administration of weekly recombinant human epo ( n = 42 ) resulted in a significant reduction in exposure to allogeneic red blood cell transfusion and higher haemoglobin levels than placebo ( n = 44 ) during the initial 42 days of epo therapy .
although not significant , the mortality rates in patients treated with epo ( 12% ) were lower than in the patients treated with placebo ( 23% ) .
the author is funded by the william harvey research foundation ( unrestricted research grant ) to study the tissue - protective effects of epo and has presented a number of invited lectures in this area of research .
Output:
| erythropoietin protects many organs against the tissue injury and dysfunction caused by ischaemia / reperfusion and excessive inflammation .
this editorial comment discusses the effects of erythropoietin in preclinical models of septic shock , endotoxemia , hemorrhagic shock , spinal cord trauma and zymosan - induced multiple organ failure . |
PubmedSumm6547 | ***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 fundamental event
in the folding and oligomerization of membrane
proteins is the association of the transmembrane ( tm ) helices .
helix
association is required to achieve the final fold and oligomeric state
of the protein . a favorite system for investigating the rules that
govern tm helix association are the single - span membrane proteins , primarily because a variety of methods are available for measuring
their oligomerization ( including fret , sedimentation equilibrium analytical
ultracentrifugation , in vivo assays in biological
membranes , sds - page , and steric trapping ) .
conversely , assessing the folding energetics of multispan membrane
proteins still represents a tremendous challenge .
in addition to being a tractable system , the single - span membrane
proteins attract interest because of their biological importance .
these proteins comprise the most numerous class of membrane proteins ,
constituting about half of the total . rather than acting as
mere membrane anchors for soluble domains ,
as it was once assumed ,
the oligomerization of single tm domains actively plays roles in assembly ,
signal transduction , ion conduction and regulation in a wide variety
of biological processes . to investigate
the basis of oligomerization in tm helices , our
group and others have pursued a strategy based on the analysis of
frequently occurring association motifs .
one of the most important motifs is gasright ( figure 1 ) , which is
best known as the fold of a widely studied model system for tm association ,
the glycophorin a tm dimer .
gasright gets its name from its right - handed crossing angle ( figure 1b ) , and from the characteristic small amino acids
at its interface ( gas : gly , ala , ser ) , which are arranged to form gxxxg and gxxxg - like patterns ( gxxxa ,
axxxg , etc . ) . in many ways
gasright parallels the important coiled coil , a frequently occurring interaction
motif and model for folding and association for soluble proteins . like the coiled coil
, gasright is characterized by a
specific geometry ( a short interhelical distance and a crossing angle
near 40 ) , it has a distinctive sequence signature ( the
gxxxg patterns ) , and is one of the most common oligomerization motifs ,
if not the most common . structural features of
the gasright tm association motif .
( a ) the gasright motif ( which is best known as the fold
of the tm region of glycophorin a ) is a right - handed helical dimer
with a short interhelical distance d and a right - handed
crossing angle of approximatively 40. the gxxxg
sequence pattern near the crossing point ( marked in red in the green
helix ) allows the backbones to come into close contact .
( b ) the contact
enables the formation of networks of interhelical hydrogen bonds between
ch donors and carbonyl oxygen acceptors ( shown in detail
in ( c ) ) . in a recent computational analysis
of transmembrane dimer geometry
,
we proposed that the primary role of gxxxg in gasright is
to promote the formation of networks of stabilizing hydrogen bonds
between ch donors and carbonyl oxygen acceptors on
opposed helices ( figure 1b , c ) .
more specifically , we proposed that the small amino
acids perform two distinct functions : the first is to create permissive
steric conditions , allowing the two helices to come in backbone contact ,
thus bringing the ch donors and carbonyl acceptors
in proximity
. the second function , which is performed exclusively
by gly , is to increase the number of hydrogen bonds by donating with
the second h , which corresponds to the side chain r - group in
all other amino acids . to perform these functions ,
the formation
of this network of hydrogen bonds is also dependent on the specific
crossing angle of gasright ( 40 ) , which precisely
aligns ch donors spaced at i , i+1 on one helix against carbonyl acceptors spaced at i , i+3 on the opposing helix ( see figure
4 in mueller et al . ) .
carbons are generally weak donors , but the c
in proteins is activated by the electron - withdrawing amide groups
on both sides , and quantum calculations indicate that the energy of
ch hydrogen bonds may be as much as one - third to half
of that of canonical donors in vacuum . therefore ,
they are likely to be stabilizing factors in proteins embedded in
the hydrophobic milieu of the membrane , particularly when they occur
in multiple instances at the same interface , as in the gasright motif ( figure 1 ) . an ir - based investigation of the cd2 stretching mode
of a ch donor in the transmembrane domain of glycophorin
a produced an estimated contribution of 0.88 kcal / mol for
the hydrogen bond .
conversely , a folding
study of the multispan membrane protein bacteriorhodopsin in which
a cho side chain hydroxyl acceptor
( thr-24 ) was mutated indicated that this particular bond was not stabilizing .
subsequent computational work suggested that
the orientation of the groups can determine whether an interaction
may be strongly favorable or unfavorable .
the exact contribution of hydrogen bonds to membrane protein
folding
and association whether the donor is a ch
or a more canonical n h or o h group
is still unresolved .
a governing
assumption maintains that donors and acceptors buried in the membrane
would not pay a significant desolvation penalty upon helix association ,
and therefore the formation of hydrogen bonds should contribute appreciably
to the stability of membrane proteins .
yet , the limited number of experimental
observations made to date seem to indicate that the contribution of
hydrogen bonding in the membrane may be , surprisingly , of the same
magnitude observed for water - soluble proteins . despite the scarce experimental evidence regarding
the contribution
of ch hydrogen bonds to tm interactions , the hypothesis
that they drive folding and oligomerization remains compelling . in
particular
, the fact that the prevalent gasright motif
corresponds to the only interhelical geometry that maximizes formation
of cho = c networks , strongly
suggests that these bonds are indeed a major contributor to association . under these premises
, we hypothesized that a
computational structural search based on the simultaneous optimization
of side chain packing and ch hydrogen bonding may be
able to predict the structure of gasright dimers .
the resulting
program , named catm , was tested against the small database of known
gasright homodimeric structures .
the finding provides further indirect support that ch
hydrogen bonding is likely to be a structural determinant of gasright dimers .
the positive result
also indicates that catm may be a powerful tool for assisting the
experimental investigation of gasright homodimers of unknown
structure . to test the ability of our methods to predict ab
initio the structure
of unknown gasright dimers ,
here we investigate adck3 ,
a human mitochondrial protein that is a member of the highly conserved
ubib protein kinase - like family .
ubib
family members account for approximately one - quarter of microbial
pkl sequences , are ubiquitous among eukaryotes , and are strongly associated with lipid metabolism .
most organisms have a ubib family member
that is required for the biosynthesis of coenzyme q ( coq , ubiquinone ) .
deletion of the escherichia
coli gene ubib(54 ) or the yeast gene coq8(55 ) completely halts coq biosynthesis .
similarly ,
mutations to human adck3 are known to cause coq deficiency and cerebellar
ataxia , and mutations to human adck4 were recently shown to cause coq deficiency
and a steroid - resistant nephrotic syndrome .
our knowledge of the molecular mechanism by which ubib family proteins
enable coq biosynthesis is limited , primarily because the endogenous
substrates of ubib proteins have not yet been discovered . however ,
we do know that coq8p in yeast somehow stabilizes a complex of coq
biosynthesis enzymes .
coq biosynthesis
occurs within the context of cellular membranes , either the plasma
membrane of prokaryotes or the inner mitochondrial membrane of eukaryotes ,
and the responsible enzymes are either integral membrane proteins
or peripherally associated membrane proteins .
adck3 , which contains a predicted tm domain , is also likely to associate
with membranes , but this hypothesis has not yet been tested . biochemical
characterization of the adck3 tm domain would provide an important
foundation for understanding how it enables coq biosynthesis .
the potential functional importance of the adck3 tm region is underlined
by the existence of a mutation at the putative edge of the tm domain
( r213w ) that disrupts coq biosynthesis and causes cerebellar ataxia
in human patients .
furthermore , dimerization
of single - span tm domains is known to be central to the regulation
of some kinase families , such as the receptor tyrosine kinases .
however , it was unknown whether the predicted tm helix of adck3
could actually insert into biological membranes and whether the tm
helix can self - associate to potentially drive dimerization of adck3 . here , we demonstrate experimentally that the tm domain of adck3
inserts into membranes and self - associates . using extensive mutagenesis
,
we also show that the interaction interface is consistent with the
structural models predicted by catm , which involves an extended gly - zipper
motif ( i.e. , a series of gly amino acids
separated at i , i+4 ) .
the experimental
and computational data also indicates that the gly - zipper interface
is potentially compatible with alternative conformations of the tm
domain , opening the possibility that conformational changes of the
tm dimer may be important for adck3 function .
all oligonucleotides were purchased
in desalted form from integrated dna technologies and used without
purification .
the expression vectors pcckan , pccgpa - wt , and pccgpa - g83i ,
and male deficient e. coli strain
mm39 were kindly provided by dr .
the genes encoding the tm domain of adck3 ( 214-lanfgglavglgfgala-230 )
and adck4 ( 92-lanfgglavglglgvla-108 ) were cloned into
the nhei - bamhi restriction sites of the pcckan vector .
site directed mutations to produce single amino acid variants in the
tm domain of adck3 were introduced with the quikchange kit ( stratagene ) .
a freshly streaked colony
was inoculated into 3 ml of lb broth containing 100 g / ml ampicillin
and grown overnight at 37 c .
30 l of overnight cultures
were inoculated into 3 ml of lb broth and grown to an od420 of approximately 0.81.1 ( od600 of 0.4 to 0.6 )
at 37 c . after recording the optical density ,
1 ml of cells
was spun down for 10 min at 17000 g and resuspended
in 500 ml of sonication buffer ( 25 mm tris - hcl , 2 mm edta , ph 8.0 ) .
cells were lysed by probe sonication at medium power for 8 s over
ice .
an aliquot was removed from each sample and stored in sds - page
loading buffer for immunoblotting .
the lysates were then cleared by
centrifugation at 17000 g , and the supernatant was
kept on ice for chloramphenicol acetyltransferase ( cat ) activity assay . to confirm proper membrane
insertion and orientation of the toxcat constructs , overnight cultures
were plated on m9 minimal medium plates containing 0.4% maltose as
the only carbon source and grown at 37 c for 48 h. cat activity
briefly , 1 ml of buffer containing 0.1 mm acetyl coa , 0.4 mg / ml
5,5-dithiobis(2-nitrobenzoic acid ) or ellman s reagent ,
and 0.1 m tris - hcl ph 7.8 , were mixed with 40 l of cleared
cell lysates and the absorbance at 412 nm was measured for 2 min to
establish basal enzyme activity rate .
after addition of 40 l
of 2.5 mm chloramphenicol in 10% ethanol , the absorbance was measured
for an additional 2 min to determine cat activity .
the basal cat activity
was subtracted and the value was normalized by the cell density measured
as od420 .
all measurements were determined at least in
duplicate and the experiments were repeated at least twice .
the cell lysates ( 10 l )
were loaded onto a nupage 412% bis - tris sds - page gel ( invitrogen )
and then transferred to pvdf membranes ( vwr ) for 1 h at 100 millivolts .
blots were blocked using 5% bovine serum albumin ( us biologicals )
in tbs - tween buffer ( 50 mm tris , 150 mm nacl , 0.05% tween 20 ) for
2 h at 4 c , incubated with biotinylated anti - maltose binding
protein antibodies ( vector laboratories ) overnight at 4 c , followed
by peroxidase - conjugated streptavidin ( jackson immunoresearch ) for
2 h at 4 c .
blots were developed with the pierce ecl western
blotting substrate kit and chemiluminescence was measured using an
imagequant las 4000 ( ge healthsciences ) .
the structure of adck3-tm was
predicted with catm , which is distributed
with the open source msl c++ library v. 1.2 at http://msl-libraries.org .
the computational mutagenesis
was performed on all adck3 models by applying the same point mutations
measured experimentally in the context of a fixed backbone , followed
by side chain optimization .
side chain mobility was modeled using
the energy - based conformer library applied at the 95% level .
energies were determined using the charmm 22
van der waals function and the hydrogen
bonding function of scwrl 4 , as implemented
in msl , with the following parameters
for c donors , as reported previously : b =
60.278 ; d0 = 2.3 ; d = 1.202 ; max = 74.0 ; max = 98.0. the relative
energy of each mutant was calculated aswhere ewt , dimer and emut , dimer are the energies of the
wild type and mutant sequence , respectively , in the dimeric state ,
and ewt , monomer and emut , monomer are the energies of the wild type and mutant
sequence , respectively , in a side chain optimized monomeric state
with the same sequence . as reported previously ,
the effect of each mutation was classified in four categories
( analogous to the experimental mutagenesis ) using the following criterion :
category 0 , wt - like , emut < 2 kcal / mol ; category 1 , mild , 2
emut < 4 ; category 2 , severe ,
4 emut < 8 ; category
3 , disruptive , emut 8 .
the numerical category values were averaged to calculate
the average position - dependent disruption value .
the protein kinase - like
domain of adck3 is preceded on the n - terminal side by a region of
undefined function .
a predicted tm helix within this region is annotated
in uniprot for the close homologue adck4 , providing a potential anchor for the protein at the inner mitochondrial
membrane ( figure 2a ) .
uniprot does not report
a predicted tm domain for the corresponding region of adck3 , but the
sequence of the putative tm segment is highly conserved between the
two proteins .
the same general domain organization and function is
also predicted for the yeast homologue coq8p . given that adck3 and
adck4 are localized to the mitochondrial matrix , the tm domain would position their catalytic kinase domains
on the matrix face of the inner membrane , the same localization of
the enzymes involved in the biosynthesis of coenzyme q. therefore , it is important to verify the tm domain experimentally
and to investigate its potential functional role .
( a ) domain organization of adck3 homologues , which are proteins associated
with the mitochondrial inner membrane .
they are predicted to contain
a tm domain ( yellow ) and a protein kinase - like domain ( white ) .
( b )
the sequence alignment of the tm domains of adck3 , adck4 ( yellow box ) .
the tm domains of adck3 and adkc4 , which differ only at two positions ,
contain a number of gxxxg - like motifs , including an extended gly - zipper
motif ( red ) and a second axxxg motif which is off - register by two
positions ( magenta ) .
( c ) sequence logo of the alignment of 400 sequences
homologous to adck3 from a broad range of eukaryotic species highlights
conservation in the tm domain and in the n - terminal side of the juxta - membrane
region .
all gly positions in the gly - zipper ( red ) appear strongly
conserved .
identifiers of the sequences used for the alignment are
provided in supplementary text s1 ( si ) .
the sequences of the putative
tm domains of adck3 and adck4 are
aligned in figure 2b .
as summarized in table 1 , these sequences have low hydrophobicity and a
relative short length ( 17 amino acids ) , and thus are not well recognized
by prediction servers .
the tm domain of adck3 , which contains one
polar amino acid ( asn 216 ) , is recognized as a borderline tm sequence
by most servers .
specifically , the segment is not recognized by tmhmm and e(z ) , but the
segment is predicted as transmembrane by membrain and hmmtop , and phobius and g prediction recognize it with low confidence .
adck4 shares over 50% sequence
identify with adck3 but their tm domains are almost identical , differing
only at two positions ( figure 2b ) . because
of these two substitutions ( and primarily because of the a228 v substitution ) ,
the hydrophobicity of the tm domain of adck4 is higher ( as calculated
with either the wimley - white octanol scale or the biological scale ) and is sufficient to be predicted by most servers , except e(z ) ,
with good confidence ( table 1 ) .
wimley white
octanol scale
( kcal / mol ) . biological hydrophobicity scale
( kcal / mol ) .
g predictior at http://dgpred.cbr.su.se ( in paretheses
the gapp for the predicted tm segment ,
kcal / mol ) .
it is important to consider
that tm prediction servers are trained against a majority of proteins
that are inserted in the membrane via a translocon mediated mechanism .
the sequence requirements for translocon mediated insertion in an
eukaryotic system are well understood .
a recent analysis
in a bacterial system shows good overall correspondence to the mammalian
system , but the hydrophobicity threshold appears to be distinctly
lower .
much less is known about the requirements
for membrane insertion of mitochondrial integral membrane proteins
that are encoded in the nucleus , such as adck3 .
there is , however ,
good indication that the hydrophobicity threshold for these proteins
should be even lower , to avoid mistargeting of these proteins to the
endoplasmic reticulum and to facilitate their translocation to the
mitochondrion .
based on the above considerations , it is highly probable that the
predicted tm segments of adck3 and adck4 are indeed bona fide tm domains .
as
shown in figure 2b , the predicted tm regions
of adck3 and adck4 are very rich in small amino acids such as gly ,
ala and ser ( 9 in each ) .
the sequences contain a number of gxxxg and
gxxxg - like ( axxxg ) helix association patterns , which appear to be
evolutionarily conserved ( figure 2c ) .
in particular ,
they contain an extended gly - zipper motif , i.e. , a series of small amino acids ( 215-axxxgxxxgxxxg-227 ) spaced
at i , i+4 , highlighted in red in
figure 2b .
they also contain an additional
axxxg motif ( magenta ) , which is off - frame by two positions with respect
to the gly - zipper .
they occur with high frequency
in tm helices , both in multispan proteins
and in oligomerizing single - span membrane proteins , and are often important for biological function .
the presence of gxxxg - like motifs in the putative
tm sequence of adck3 raised the question of whether this domain oligomerizes .
to investigate this question
, we analyzed the sequence with catm , a program for the structural prediction of gasright motifs , an important and common class of gxxxg - mediated
dimers .
as shown in figure 3 , catm predicts five alternative models for the
tm sequence of adck3 .
the position of the crossing point between
the two helices is marked ( dot ) , and the interfacial positions that
surround this crossing point are highlighted by a green parallelogram .
all the positions that are involved in intermonomer contacts at the
interface are highlighted in either yellow , or in red if they belong
to the gly - zipper motif .
the scores of the top models of adck3 in
catm ( 59.8 , 50.8 , and 47.7 for models 1 , 2 ,
and 3 respectively ) are comparable to the scores obtained for the
five known structures of gasright motifs ( which range between
56 and 38 ) , which catm is able to predict at near
atomic precision .
catm predicts multiple
modes of interaction along the gly - zipper
motif of adck3 .
the four positions that surround the
crossing point are marked by a green parallelogram and are underlined
in the sequence .
the positions involved in interhelical packing at
the dimer interface are highlighted : in red are the interfacial positions
that belong to the extended gly - zipper motif of adck3 ; all other interfacial
positions are highlighted in yellow .
the table summarizes the geometry
of the five models : interhelical distance d ; crossing
angle ; vertical ( z ) and axial ( )
coordinates of the crossing point within the parallelogram of closest
approach ; and energy score e. for the geometric definitions ,
see figure s2 ( si ) and mueller et al .
model 1
and 2 are related geometries whose crossing points fall in the quadrilateral
defined by gly 219 , leu 220 , gly 223 and leu 224 ( axxxglxxglxxg ) .
these two models differ by the position of the crossing point and ,
most importantly , by their crossing angle , which is near the canonical
40 of gasright motifs for model 2 , and narrower
for model 1 ( 27.1 ) .
the smaller crossing angle causes
model 1 to have a more extended interface , which is reflected also
by the more extensive van der waals interaction of model 1 .
both models
have 12 interhelical ch hydrogen bonds , although model
2 has a better overall hydrogen bonding score ( tables s1 and s2 ( si ) ) .
the other three predicted models
cross at different sections of
the gly - zipper .
model 3 and model 5 are variations that cross within
the n - terminal side of the zipper ( anxxglxxgxxxg ) .
conversely ,
model 4 crosses on the c - terminal side of the zipper ( axxxgxxxglxxga ) .
catm does not produce any model mediated by the off - frame
axxxg motif of adck3 ( magenta in figure 2b ) .
the coordinates of all adck3 models are available as supporting information and for download at http://seneslab.org/adck3_models . to investigate the structural predictions of
catm
, we assessed the dimerization of adck3-tm and adck4-tm experimentally
using toxcat , a widely used assay for tm association in biological
membranes .
this assay involves the biological
expression in the membrane of e. coli of a chimeric
construct that fuses the tm domain of interest with the toxr transcriptional
activator of vibrio cholera ( figure 4a ) .
tm helix association
leads to the dimerization of the toxr domain , resulting in expression
of the reporter gene chloramphenicol acetyltransferase ( cat ) . the
expression level of cat ( measured by its enzymatic activity )
is compared
to that of a stable dimer , glycophorin a ( gpa ) , and to a monomeric
gpa variant ( gpa - g83i ) as standards . adck3-tm and adck4-tm associate strongly
in toxcat .
( a ) toxcat
is an in vivo assay based on a construct in which the transmembrane
domain under investigation is fused to the toxr transcriptional activator
of v. cholerae .
transmembrane association results
in the expression of a reporter gene in e. coli cells ,
which can be quantified .
the toxcat construct containing the tm domain of adck3 and
adck4 can use maltose as a carbon source , demonstrating correct insertion .
gpa : glycophorin a positive control ; no tm : pcckan plasmid without
tm insert , negative control .
adck3 shows approximately 150% of the cat activity of the strong transmembrane
dimer of glycophorin a ( gpa ) .
the monomeric g83i mutant ( gpa * ) is
used as a negative control .
we first tested whether the constructs inserted correctly
in the
plasma membrane of e. coli , using a complementation
test in the male deficient strain mm39 .
the adck3-tm
and adck4-tm toxcat constructs supported growth in minimal media with
maltose as the sole carbon source ( figure 4b ) , indicating that the fusion proteins are recognized as tm domains
and are expressed in the bacterial inner membrane in the correct orientation ,
with the mbp moiety positioned on the periplasmic side . to examine
whether adck3 oligomerizes in toxcat , we quantified
the enzymatic activity of the reporter gene cat , as an indirect measure
of its expression .
as shown in figure 4c , the
cat activities of the adck3-tm and adck4-tm constructs are higher
than the activity of the gpa standard , which is a stable homodimer .
these results indicate that the tm domain of adck3 and adck4 form
strong homo - oligomers in toxcat . to assess experimentally the
interaction interface of the adck3-tm oligomer and validate the computational
predictions , we performed large scale mutagenesis along the entire
span of the tm segment , and measured their self - association in toxcat .
each position was individually changed to a variety of large and small
hydrophobic amino acids .
the expectation is that the changes at interfacial
positions are more likely to perturb oligomerization than changes
at lipid exposed positions , as commonly observed ( for example ) .
the toxcat data is shown in figure s1 ( si ) and is schematically represented in figure 5a . to compute an overall position - dependent sensitivity to mutation
,
we applied a classification scheme for the variants phenotypes
using four categories ( dashed lines in figure
s1 ( si ) ) , labeled as wt - like ( > 80% of wild
type cat activity ) , mild ( 5080% ) , severe
position - based averaging reduces some of the natural
variability of the biological assay and the method has been reliable
in identifying the most sensitive positions at the helix
mackenzie
plot summarizing the effect of all mutations of adck3-tm measured
in toxcat .
the color coding of the gxxxg motifs in the sequence corresponds
to figure 1 .
a calculated average disruption
score for each position is displayed at the bottom of the scheme .
( b ) the same average disruption plotted numerically ( 0 = as tw ; 3
= disruptive ) .
the mutagenesis reveals two positions that are essential
for self - association , g223 and g227 , which are the last two position
of adck3s gly - zipper ( red ) .
a majority of the variants had cat activity levels similar
or higher
compared to the wild type sequences ( figure 5b ) .
however , a number of variants showed dramatically reduced activity
in a position specific fashion . in particular , all variants of the
two c - terminal gly residues of the gly - zipper ( g223 and g227 ) have
the strongest disruptive phenotypes .
interestingly , the next most
sensitive positions are l220 and l224 , which are also predicted to
be interfacial in almost all catm models ( figure 3 ) .
conversely , the n - terminal positions of the zipper are
either mildly affected by mutation ( g219 ) or appear completely tolerant
( a215 ) .
the off - frame 221-axxxg-225 ( magenta ) is also relatively
insensitive
to mutation .
substitution for a large leu at these two positions has
only a mild effect , and the ile variants are completely tolerated .
this is consistent with the catm predictions , which do not identify
any model in which this motif is at the interface .
polar
residues can drive tm helix oligomerization through the formation
of hydrogen bonds , and have been found to be important for the association
of model peptides and of biological systems , including in the context of gasright motifs .
in addition , some polarity of position 216 appears to be relatively
conserved , as the main substitutions of n216 in a sequence alignment
( figure 2c ) are gly , ser , gln and glu . however ,
neither the computational nor the experimental analysis suggest that
n216 is important for self - association .
asn 216 can be mutated to
ala , leu or phe in toxcat without reduction of self - association .
catm
is in agreement with the experimental data , as it does not identify
any potential strong polar interaction ( i.e. , n
ho
hydrogen bonds ) involving the side chain of n216 , although the side
chain carbonyl oxygen ( o1 ) acts as a ch bond
acceptor in most models .
overall the data indicates that the
interface of the adck3-tm oligomer
is mediated by gly - zipper motif and , in particular , by the c - terminal
side of this interaction motif . in order to identify the structure most consistent
with the toxcat data
, we performed a mutational analysis of the five
models generated by catm . using a protocol developed previously to
analyze similar mutational data
, we created
in silico the same set of variants that were tested experimentally ,
and computed an analogous position - dependent average disruption
given that all catm structures interact through portions
of the extended gly - zipper , the computed patterns have similar periodicity
across all models , with disruption peaking at position g219 , g223
and/or g227 .
models 1 , 3 , and 5 ( figure 6a , c , e )
show high sensitivity to mutation on the n - terminal side of the tm
domain , in disagreement with the experimental observations . in these
three models , mutations to g219
models 1 and 5 are
also very sensitive at positions a215 and n216 , which are completely
tolerant experimentally .
comparison
of the mutagenesis obtained in toxcat ( same as figure 5b ) with the computational mutagenesis performed on the five
catm models ( a e ) .
the comparison suggests that model 2 is
the best fit to the experimental data , followed by model 4 .
( f ) a
linear combination of model 2 ( 60% ) and model 4 ( 40% ) produces an
excellent fit to the data , suggesting that the tm of adck3 may be
in equilibrium between at least two conformations in the toxcat system .
model 2 ( figure 6b ) and
model 4 ( figure 6d ) are in better agreement
with the experimental data and represent two possible structural solutions
for the adck3 tm dimer .
the disruption for both models peak at g223
and g227 , which are also the two most disruptive positions in toxcat .
however , model 4 appears insensitive at position g219 ( which is mildly
sensitive experimentally ) and it is extremely disruptive at position
a228 ( which is insensitive experimentally ) .
in addition to being a
better match , model 2 also has lower energy , better packing and a
larger number of hydrogen bonds ( tables s2 and
s4 ( si ) ) .
therefore , model 2 appears to be the best structural
candidate for the adck3 tm dimer .
structural models 2 and 4 . comparison
of the structures of catm
models 2 and 4 for adck3 . from left to right , entire tm helix , detail
of the interface , and same conformation in full atom spheres .
model
2 has lower energy , a larger number of hydrogen bonds ( 12 in model
2 versus 4 in model 4 ) and more extended and complementary packing . in a recent analysis of known
gasright structures
, we
demonstrated that catm is capable of capturing alternative conformations
of biological importance .
therefore ,
an additional possibility is that the tm domain of adck3 may be in
equilibrium between two or more structures .
we observed that a linear
combination of the mutagenesis profiles of the two models that best
fit the data , 60% of model 2 and 40% of model 4 , improves the fit
with the toxcat data , producing an excellent correspondence between
the two experiments ( figure 6f ) .
this interpolation
is not necessarily quantitative , but it suggests that a conformational
equilibrium would be compatible with the data . if such an equilibrium
occurs in the biological context , it would postulate that the tm domain
of adck3 may be a switchable element , a trait that could be important
for regulation or signaling , as observed in a number of other single - span
tm proteins . in this framework ,
the gly - zipper
would provide a dynamic interface for structural changes that could
potentially affect either the distance of the helical termini or the
relative rotation of the helices .
we
have presented a computational and experimental analysis of
the structural organization of the tm domain of the mitochondrial
kinase adck3 .
while more experiments are necessary to fully test catm ,
the work provides a first practical demonstration of the applicability
of the program to the characterization of a tm dimer of unknown structure .
it also confirms the ability of the algorithm ( which is based on optimization
of van der waals and ch hydrogen bonding ) to correctly
predict gasright motifs .
we have experimentally demonstrated
that the tm domain of adck3
self - associates in e. coli membranes . while the specific
oligomeric state could not be determined by toxcat
although gly - zipper motifs can be
involved in the formation of higher - oligomeric complexes , the good agreement between the experimental
and computational mutagenesis supports the homodimeric hypothesis .
moreover , such oligomeric state is also consistent with a large body
of structural evidence , which shows that kinases frequently form dimeric
complexes ( for example ) , while higher oligomers are
rarely observed .
helix interaction interface was determined
and the mutagenesis identified a number of disruptive interfacial
mutations that will be useful for follow - up functional studies .
the
computational prediction of alternative models in which the helices
adopt a different crossing point along the gly - zipper interface raises
also the hypothesis that the tm domain of adck3 may possibly undergo
conformational changes .
indirectly , the work also provides important
insight about adck4 .
all the amino acids that participate at the dimerization interface
of adck3 are identical in adck4 .
the two positions that differ between
the two sequences ( f228l and a230 v , figure 2 ) are insensitive to variation when they are mutated individually
( figure 5 ) .
the computational predictions obtained
for adck3 and adck4 are nearly identical , and it is thus expected
that both tm domains dimerize with the same structure . because the
two interfaces are compatible with each other , it also possible that
the tm domains could associate to drive formation of a heterodimeric
complex between adck3 and adck4 .
these hypotheses need to be investigated
in a biological context ; the present analysis provides the theoretical
foundation necessary for testing in vivo the role of these tm domains .
Output:
| interactions
between -helices within the hydrophobic environment
of lipid bilayers are integral to the folding and function of transmembrane
proteins ; however , the major forces that mediate these interactions
remain debated , and our ability to predict these interactions is still
largely untested .
we recently demonstrated that the frequent transmembrane
association motif gasright , the gxxxg - containing fold of
the glycophorin a dimer , is optimal for the formation of extended
networks of ch hydrogen bonds , supporting the hypothesis
that these bonds are major contributors to association .
we also found
that optimization of ch hydrogen bonding and interhelical
packing is sufficient to computationally predict the structure of
known gasright dimers at near atomic level . here ,
we demonstrate
that this computational method can be used to characterize the structure
of a protein not previously known to dimerize , by predicting and validating
the transmembrane dimer of adck3 , a mitochondrial kinase .
adck3 is
involved in the biosynthesis of the redox active lipid , ubiquinone ,
and human adck3 mutations cause a cerebellar ataxia associated with
ubiquinone deficiency , but the biochemical functions of adck3 remain
largely undefined .
our experimental analyses show that the transmembrane
helix of adck3 oligomerizes , with an interface based on an extended
gly - zipper motif , as predicted by our models .
the data provide strong
evidence for the hypothesis that optimization of ch
hydrogen bonding is an important factor in the association of transmembrane
helices .
this work also provides a structural foundation for investigating
the role of transmembrane association in regulating the biological
activity of adck3 . |
PubmedSumm6548 | ***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:
| a general ,
asymmetric synthesis of amino acid derivatives is reported .
masked
acyl cyanide ( mac ) reagents are shown to be effective umpolung synthons
for enantioselective additions to n - boc - aldimines .
the reactions are catalyzed by a modified cinchona alkaloid , which
can function as a bifunctional , hydrogen bonding catalyst , and afford
adducts in excellent yields ( 9098% ) and high enantioselectivities
( up to 97.5:2.5 er ) . unmasking the addition products
gives acyl cyanide
intermediates that are intercepted by a variety of nucleophiles to
afford -amino acid derivatives .
notably , the methodology provides
an alternative method for peptide bond formation . |
PubmedSumm6549 | ***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: testicular cancer is a rare disease ; it occurs most commonly in young men in their third to fifth decade of life and accounts for about 13% of all cancers in men in western countries and about 17% of cancers in men below 45 , .
germany is one of the countries with the highest incidence rates of testicular cancer , with an estimated age - standardized incidence rate ( europe standard ) of 11.1/10 in 2004 .
the risk factors associated with testicular cancer are not very well known apart from the association with cryptorchidism ( undescended testis ) documented in multiple studies , , , , , , familial association and exposure to high level of estrogen in utero .
some occupational exposures were suggested to be associated with a higher risk for testicular cancer .
rural residence during adulthood was associated with an increased risk of testicular cancer in italy ( odds ratio ( or ) = 3.31 ; 95% confidence interval ( ci ) 1.368.01 ) ; use of pesticides in gardening was similarly associated with an elevated or of 1.83 ( 95% ci 1.023.29 ) .
further relevant occupations seem to include fire fighters and carpenters . in professional fire fighters in florida
the standardized incidence ratio ( sir ) was 1.60 ( 95% ci 1.202.09 ) , and similar results were obtained in new zealand and in germany .
studies concerning carpenters also showed an increased risk for testicular cancer ; in new jersey the sir of testicular cancer for carpenters between 19792000 was 1.29 ( 95% ci 0.782.01 ) . the incidence rate was increased after a 15-years lag from initial work date ( sir=2.40 ; 95% ci 1.294.32 ) , with similar results documented in germany .
results for selected other occupations have shown inconsistency associated with an increased risk of testicular cancer . a study on
vietnam war veterans showed a twofold elevated risk for testicular cancer with an or of 2.5 ( 95% ci 1.15.7 ) .
no clear associations were seen for metal workers , but paper and pulp maintenance workers ( and not process workers ) in sweden had higher risk of testicular cancer . no clear risk was observed for professional and technical workers . in order to shed more light on the occupational risk factors of testicular cancer and to assess the feasibility of a registry - based case - control study , data from the cancer registry of the german federal state of rhineland - palatinate were used to conduct a case - control study for testicular cancer , where both the cases and controls were cancer patients registered in the years 20002005 . because of the small number of cases , only broad occupational categories , with limited specificity regarding occupational exposures were used .
the study population includes cases and controls with registered malignancies in the rhineland palatinate cancer registry for the period 20002005 .
cases of testicular cancer diagnosed between 2000 and 2005 in the cancer registry and having occupational information were compared to a set of cancer diagnoses which were chosen to represent the controls pool .
these included primary cancer of the stomach , colon , pancreas , kidney , hodgkin s lymphoma , thyroid , and lip , oral cavity and pharynx .
these cancer types were selected because there was no strong indication of their association with occupational risk factors , , , , , , , .
additionally , these cancers affect a wide age group including young patients which made it possible to broadly match them to testicular cancer patients basing on age groups , . from the group of 15,868 potential controls ,
controls were matched by 5 years age groups ( 24 , 2529 , 3034 , 3539 , 4044 , 4549 , 50 ) , giving priority to controls with occupational information .
the selection probabilities for the controls were 1 for the age groups 24 , 2529 , 3034 , 3539 , 0.26 for the age groups 4044 , 4549 and 0.02 for the age group 50 . however , not all the cancer types included in the control pool eventually contributed controls to be matched to our cases , either due to absence of registered patients in specific age group ( mostly people younger than 40 years ) or because of missing occupational information . as a result of these restrictions , only a subset of cancers ( colon , pancreas , kidney , thyroid cancers and hodgkin s lymphoma ) eventually formed our control population from the potential control pool .
frequency matching was implemented because of the relatively young age of testicular cancer cases which rendered the selection of individually matched controls rather difficult .
they were re - coded according to the international standard classification of occupations version 2008 , for better comparability with international results . due to the very large proportion of registrations with missing occupational information in the control population ( about 70% of the potential controls in the cancer registry ) a decision to include only cases and controls with job titles indicating gainful occupations in the analyses
the availability of job information for the potential controls in the age groups 2549 was similar to that of testicular cancer patients as shown in table 1 ( tab .
the stepwise process of controls selection is illustrated in more details in figure 1 ( fig .
1 ) . because of the relatively small number of cases , the analysis included only the major occupational groups and the main subgroups rather than specific job titles to avoid diluting any possible effects .
the analysis of the case - control study included calculating the odds ratio for the different jobs via unconditional logistic regression in relation to the different job titles .
the reference group for the analysis was all the other occupations combined against the occupational title under study . to investigate the effect of this approach ,
a sensitivity analysis was done with another reference group including a set of occupational titles with no proven associations with testicular cancer risk reported in the literature ( armed forces , services and sales workers , skilled agriculture , and elementary occupations ) .
age - group specific odds ratios for the occupational distribution of the patients in the highest risk age group ( 2050 ) were also calculated .
no additional adjustment for confounders could be done as no relevant additional information on cases and controls is available in the registry .
there were 864 primary testicular cancer cases and 718 age matched controls selected from the rhineland - palatinate cancer registry .
for the analysis 348 cases and 564 cancer controls with gainful occupational information were available .
the vast majority of the cases and controls were verified histologically ( 95.5% and 97.5% respectively ) ( table 2 ( tab .
3 ) . there was a significant risk elevation for technicians and associate professionals , or=1.62 ( 95% ci 1.002.63 ) and clerical support workers , or=1.71 ( 95% ci 1.142.56 ) mostly for the subgroup general and keyboard clerics with an or=1.83 ( 95% ci 1.212.77 ) . in analyses stratified by age group
the or for the technicians and associate professionals and the clerical support workers was also elevated for the age - group 2050 years , or=2.02 ( 95% ci 1.233.33 ) and 2.00 ( 95% ci 1.303.09 ) respectively ( table 4 ( tab .
4 ) ) . when the or was calculated against a selected group of occupations as reference ( see methods ) , no significant increase was noted for any of the occupations , but the directions of associations were unchanged ( table 5 ( tab .
this is the first registry - based case - control analysis to be conducted in the rhineland palatinate cancer registry , where both cases and controls were anonymously derived from the registry database .
the registry has a good completeness of over 90% ( and 95% for testicular cancer ) .
the study showed a slight increase in the or for testicular cancer in association with occupational codes related to
technicians and associate professionals and to clerical support workers . however , due to the large number of missing occupational data these results need to be viewed with great caution .
the feasibility of the registry - based case - control approach was tested with a view to better utilize the data stored in the cancer registry . however , this approach was associated with some difficulties .
the use of cancer cases as controls instead of the general population might raise concerns regarding the findings of this study .
however , the cancer types included in our control group are generally not known to be strongly associated with occupational exposures .
thyroid cancer and hodgkin s lymphoma are considered to be associated with radiation exposure , , but this was not a limitation since testicular cancer does not seem to be associated with radiation .
other difficulties encountered include the fact that the average age of male cancer patients is usually high while testicular cancer patients are mostly young or middle - aged men .
this led to problems in finding appropriate age - matched controls for testicular cancer patients since there were very few cancers with relatively young age at occurrence .
an additional limitation of this study was the high proportion of missing occupational information for both the cases and controls .
less than 50% of all cases and a little more than 30% of the overall potential controls had occupational information available . to overcome this limitation
the analysis was restricted to cases and controls with gainful occupational information available in the registry .
this may induce selection bias if availability of occupational information is linked to other differences relevant for the comparisons performed in this study , or if particular occupations had a higher probability to be noted in the registry . while this remains a possibility , we observed a wide range of occupational codes among both cases and controls .
additionally , the availability of occupational information in the high risk age groups was similar in testicular cancer patients and the selected controls .
we found an increased risk of testicular cancer in two groups , technicians and associate professionals ; and clerical support workers .
an increase in testicular cancer risk in these groups was also reported in some previous studies , . however ,
in a large prospective study that included 7,519 incident cases of testicular cancer from denmark , finland , iceland , norway and sweden ( nocca study ) , the standardized incidence ratios ( sir ) for these occupations were only slightly elevated .
the sir for technician workers and clerical workers were 1.06 ( 95% ci 0.991.15 ) and 1.14 ( 95% ci 1.021.27 ) respectively . in the nocca study , physicians were found to have the highest risk for testicular cancer , with an sir of 1.48 ( 95% ci 1.151.88 ) . in our study
the risk for health professionals and health associate professionals was non - significantly elevated , or 2.32 ( 95% ci 0.3614.83 ) and 2.41 ( 95% ci 0.738.02 ) respectively . combining both groups into one health related jobs group resulted in an or of 1.82 ( 95% ci 0.734.54 ) .
obviously , the nordic study included a much larger number of cases in comparison to our study , did not rely on cancer controls and was much less afflicted by missing data issues , which once again underlines the need for caution when interpreting our data .
it is , however , interesting to note that both studies indicate risk elevations associated with medical occupations .
the two groups ( technicians and associate professionals and clerical support workers ) with elevated or noted in our analysis share a similar job environment , including long hours of office work .
the increase of testicular cancer risk in both technicians and clerical support workers could be expected to be related to their socioeconomic status which , although not available in the cancer registry data , may be higher than in comparison groups .
several studies have indicated that testicular cancer is associated with higher socioeconomic status , , , but more detailed mechanisms are not understood .
a possible explanation of our findings is the sedentary life style characteristic of these two groups . in a review discussing the lifestyle factors associated with testicular dysfunction , sedentary work habits
an increase in testicular temperature has long been associated with the increase in testicular cancer incidence ; however , in a study conducted in the united states , exposure to elevated temperatures ( 80f or 26.7c ) was not significantly associated with testicular cancer risk ( or 1.20 ; 95% ci 0.801.80 ) .
other studies investigating the effect of raised temperature on testicular cancer incidence have also failed to detect an association , , , .
the uk testicular cancer study group reported a protective effect of exercise against testicular cancer , whereas a positive association with sedentary life style was reported .
a canadian study also showed protective effects of moderate to high levels of recreational and somewhat less clearly for occupational activities .
an inverse association between physical activity during childhood and the risk of testicular cancer was also reported .
contrary to the above findings , many studies reported no effect , or even positive associations between testicular cancer and physical activity . in conclusion , we found a slightly increased risk of testicular cancer for both technicians and associate professionals and for clerical support workers . whether this increase is related to specific occupational exposure in those people including the lifestyle factors associated with these occupations such as increased scrotal temperature or lack of physical activity due to prolonged periods of sitting , or exposure to electromagnetic fields from electrical equipments such as laptops ,
these exposures ( heat , physical activity and exposure to electromagnetic fields ) were previously discussed as possible causes for testicular cancer among other possibilities in pulp and paper workers in sweden , a relationship was not confirmed though .
the feasibility of a registry - based case - control study in the cancer registry could be demonstrated , while limitations were highlighted . for the future ,
such studies are likely to become more informative if the amount of missing data can be reduced , as physicians provide more complete data to the registry wherever possible .
l. y.s work on this review was supported by the daad ( german academic exchange service ) as part of her doctoral study .
l. y.s work on this review was supported by the daad ( german academic exchange service ) as part of her doctoral study .
Output:
| objectives : testicular cancer affects mainly men below the age of 50 .
an association with occupation and social status has been suggested but risk factors are not well understood .
a registry - based case - control study focusing on occupation was performed in germany.methods : all 348 testicular cancer cases with available gainful occupational information registered between 2000 and 2005 ; as well as 564 suitable controls ( from a pool of other cancers ) were drawn from the cancer registry of rhineland - palatinate .
unconditional logistic regression was used to compute odds ratios ( or ) and associated 95% confidence intervals ( ci).results : slightly elevated or were observed for technicians and related professionals ( or 1.62 , 95% ci 1.002.63 ) and for clerical support workers ( or 1.71 , 95% ci 1.142.56 ) .
this increase was highest in the age group 2050 for technicians ( or 2.02 , 95% ci 1.233.33 ) and clerks ( or 2.00 , 95% ci 1.303.09 ) , respectively .
an association with testicular cancer was observed for no other occupation.conclusion : an increased risk of testicular cancer was observed for technicians and related professionals and clerical support workers .
this could be related to socioeconomic status or sedentary life style , two factors that were identified in previous studies .
while the feasibility of a purely registry - based study was shown , missing occupational data and the choice of cancer controls represent challenges to the validity of this approach . |
PubmedSumm6550 | ***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: amyotrophic lateral sclerosis ( als ) is a progressive and fatal neurodegenerative disease affecting motor neurons in the anterior horn of the spinal cord , the brainstem and the motor cortex with a pattern of progression not shared by other fatal diseases ( mitchell and borasio , 2007 ) .
it is clinically characterized by progressive increasing weakness leading to death by respiratory insufficiency usually within three years ( haverkamp et al . , 1995 ) .
als typically manifests itself as a muscle wasting or weakness in a limb or bulbar regions ( talbot , 2002 ) .
it then progresses to pervasive muscle weakness with a combination of upper and lower motor neuron dysfunction .
patients become relentlessly immobile , develop an impaired speech , often leading to social isolation . in the late stages of the disease
, progressing paralysis can result in a locked - in state in which only residual muscular movement is possible ( borasio et al . , 2001 ) , but the intellect and the personality usually remain unimpaired . the incidence of als is reported to be between 1.5 and 2.7 per 100,000 population / year ( average 1.89 per 100,000/year ) in europe and north america , with a uniform incidence across these countries ( worms , 2001 ) .
the mean age of onset for als is between 55 to 65 years , with a 5% of cases that had an onset before the age of 30 years ( haverkamp et al .
although most cases of als are sporadic , about 5% of cases have a family history of als ( mulder et al . , 1986 ) .
so far it is not possible to stop the progression of the disease therefore the primary goal in caring for patients with als is often considered to be the enhancement of their quality of life ( simmons , 2005 ) .
quality of life is generally defined in its biopsychosocial issues , which means an integration of physical and biological aspects ( i.e. , symptoms of illness or wellness ) , psychological aspects ( i.e. , emotions and thoughts ) , and social aspects ( i.e. , family relationships , social support ) ( engel , 1977 ) . all als patients show a similar clinical evolution , while loss of functions can have a different onset and has different times of worsening .
given the devastating nature of the disease , the access to a psychological support can be highly important . as well as for other very serious illness ( i.e. , cancer )
, psychological support should provide a scaffolding action , with a safe emotional space where people can express their feelings and emotions and be accompanied in the analysis of pain and fears .
psychologists can play an extremely active role in the rehabilitation process of als patients due to their capacity in providing a specific support for every phase in the disease progression .
furthermore , psychologists should help not only patients and families in understanding what is happening , but they can also play a key role in supporting the other members of the multi - professional team in their endeavor managing such an over complex framework .
the way in which als diagnosis is communicated to the patients appears to be of the most importance in determining their initial reaction ( simmons , 2005 ) .
communication of als diagnosis may cause major repeated psychological trauma which the patient will have to cope with , using defenses and adaptation mechanisms .
clinical management of als should include knowledge , understanding , and acceptance of these mechanisms .
this could be challenging for physicians , who may be unprepared to break bad news ( buckman , 1996 ) , mostly because of a lack of emotional management training ( pagnini et al . , 2009 ) .
guidelines for breaking the news to a patient with als ( borasio et al . , 1998 ) also suggest the proposal of a psychological support .
right after the communication of the diagnosis , patients often need a room in which they can express their emotions , usually despair , regarding what they will have to inevitably face in the future .
as mentioned above , the diagnostic communication of the illness is a crucial and emotionally relevant moment for the patient .
the presence of a psychologist in the medical staff can allow the patients to express their feelings and fears in a better way compared to what they would have done with the only presence of a physician .
a patient - centered service should be very careful in diagnostic communication and the clinical team should work together to enhance the quality of the patient
clinician relationship , with a particular focus on the diagnostic and prognostic communication processes . relatives and close caregivers of als patients should be able to receive psychological support from the very first period of disease
als is a huge burden to be carried , both by patients and their relatives . in the beginning
they need to cope with bereavement , caused by the knowledge about the progressive loss of motor functions and the awareness that , within a few years , the patient will probably pass away .
psychological support for families should be both expressive ( promoting mourning management ) and practical , helping relatives with discussion and practical suggestions . for example , people can be worried and confused about if and how to communicate information regarding the disease to their small children and this could be object of practical analysis in psychological counseling .
during illness progression , the awareness of an emotionally safe room , offered by the psychologist , is a great resource for patients and caregivers , improving their quality of life . during counseling
they can explore their needs , feel free to voice their emotions , guaranteeing a cathartic effect .
people can be seen alone , with their partner or as a family . at the same time it is also possible to manage other practical troubles that cause personal , familiar , or social diseases , problems that could be unrelated to the apparition of als symptoms .
sometimes clinicians need to face pre - existent issues , for example couple problems , that interact with the new medical condition .
spirituality and existential well - being issues may be addressed and explored in these interviews , with respect and the awareness that they are very powerful resources in the coping with illness and the shadow of death .
it is sometimes useful for psychologists to send patients to a spiritual counselor , according to the patients beliefs ( i.e. , a priest , a monk , maybe a philosopher ) .
spiritual care should encompass the whole family as a means of preventing complicated bereavement . throughout the course of the disease , a balance should be maintained by physicians between anticipating onsets of loss of functions and introducing life support measures , on the one hand , and respecting the patient 's psychological state , life plans , and environment , on the other .
medical knowledge is unable to reverse this process , but it can offer auxiliaries to compensate , like walkers , manual wheelchairs , or power chairs .
painful goodbye to their autonomy , a limitation of freedom . in a clinical relationship
furthermore , als patients will , sooner or later , face the loss of speech and voice .
usually there is an initial decrease of speech volume , followed by a change in the voice , becoming more confused .
this may be followed by complete loss of speech . in order to prevent devastating psychological and social consequences , patients and caregivers
in addition to technological solutions , like computerized communicators , there are different ways to communicate , like hand signals , head nodding , sign language , etc .
the psychologist should facilitate the awareness that living without speech is not living without communicating .
patient couple find a way to easily interact between them and this could be a task for psychologists .
respiratory support is usually provided by non - invasive ventilation ( niv ) or invasive ventilation via tracheotomy .
niv is the provision of ventilatory support through the patient 's upper airway using a mask or similar device , while tracheotomy is a surgical procedure on the neck to open a direct airway through an incision in the trachea .
niv is usually initially used for sporadic nocturnal support to alleviate symptoms of nocturnal hypoventilation . as respiratory function worsens , patients tend to require increasing daytime niv support and eventually continuous support . together with the emotional strain due to the decrease of respiratory functions , many patients report a rejection of the mask , describing an experience similar to claustrophobia , where they feel suffocating , feeling an increasing anxiety , and anguish .
respiratory anxiety can be treated with relaxation techniques , in particular with those related to breathe listening and control .
patient 's capacity to swallow food decreases as tongue weaknesses , while coughing and choking increase .
initially management of this dysphagia consists in urging a change in food consistency , but when this method is not enough , it is proposed a feeding gastrostomy tube to the patient ( peg or rig ) .
despite a variety in disease progression , sooner or later all als patients must face important decisions .
these choices are highly important and hard to be taken , since they will have an important impact on the patients lives .
patients should be able to make a choice with the consciousness of medical issues , communicated by physicians , but they also need time to express their fears and doubts . when patient have to decide about an intervention , an informed consent must be signed .
( 2009 ) propose a two - steps informed consent , with the communication of clinically relevant information made by physician and a second phase , after some hours or some days , where patients can explore feelings and fears to the psychologist . only in this second step
psychological support becomes even more important in the end - of - life phase of the disease .
psychologists need to be aware of potential difficulties in the bereavement outcome for surviving relatives and/or carers .
difficult questions are often asked to clinicians from both patients and caregivers , questions typically related to the suffering management at the end of life . in this period
the emotional strain is very high and can promote the breakdown of a psychological equilibrium in pre - morbid subjects .
there could be requests for assistance to die as a means of stopping the suffering .
answers to these questions should be given sensitively and honestly , considering the ability of the individuals to understand and manage the information that they are asking for .
after the patient 's death continuous counseling is often needed in order to cope with the grief of mourning .
the death of a person has a lasting effect on his family and not all people are able to cope well with the situation ( martin and turnbull , 2001 ) .
grief and bereavement support is integral to als care , but a study conducted in the us indicates that the support provided by als centers is often inadequate ( hebert et al . , 2005 ) .
measures such as the possibility to talk to the psychologist or a letter of condolence can improve this support .
a letter of condolence can help a bereaved family and tie - up the relationship between the physician and the late patient 's family ( bedell et al .
the burden experienced by als caregivers is severe , as the one experienced in caring for any other neurological disorder .
( 2003 ) analyzed the burden of als carers , comparing it with the one experienced by carers of other diseases .
they found a lower level of care burden for als , compared with dementia or mixed neuropsychiatric and internal diseases , but it was correlated with functional impairment .
personal and social restrictions and physical and emotional problems were the main burden components . given that the burden of care increases with the functional impairment , these researchers suggest that support for caregivers has to start sooner .
caregivers spend a lot of time for day caring , sometimes more than 11 h a day , despite having other assistance in the home ( krivickas et al . ,
1997 ) and those who believe they can not leave the patient are the most distressed ( rabkin et al . , 2005 ) .
als caregivers note many changes in patients , including increased tension , less frequent vacations , decreased time for themselves , increased anxiety , and decreased time for recreational activities ( mitsumoto , 2002 ) . together with emotional strain ,
care in als requires a certain amount of physical effort , in particular during the advanced phases of the disease .
patients need assistance to make movements and to get up and providing this could be a problem for people with physical impairments .
the progressive nature of the disease promote dependence of the patient upon a primary caregiver and it is important to identify factors relevant to quality of life for both patient and caregiver ( lo coco et al . , 2005 ) and to improve these as much as possible .
there is some evidence supporting the idea that caregivers influence the mental and physical status of patients with als ( chio et al . , 2004 ) .
the therapeutic team should be aware of the strengths and deficiencies of the caregivers and should help them in improving their coping skills . since concordance of depression and distress levels between patients and caregivers is high , attention to the mental health of the caregiver could alleviate the patient 's distress as well ( rabkin et al . , 2000 ) .
perceived social support is an important predictor of carer distress ( goldstein et al . , 2006 ) , marital relationship satisfaction ( o'connor et al . , 2008 ) , and patient 's quality of life ( chio et al . , 2004 ) .
however , the maintain of a network of social support may be difficult to accomplish , as friends often stop visiting or became awkward around the patient as symptoms increase in severity ( cobb and hamera , 1986 ) .
even if the enhancement of relationships may be considered as a task for other specialists , clinicians could work with caregivers and patients in order to improve their social networks , when this could have a positive influence on their well - being .
the authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest .
Output:
| amyotrophic lateral sclerosis is a fatal and progressive disease , characterized by progressive muscles weakness , with consequent loss of physical capacities .
psychologists can play an important role in als care , by providing clinical activities in every step of the disease , including support and counseling activities directed to patients , their caregivers and to physicians . |
PubmedSumm6551 | ***TASK***
the task is to summarize an input biomedical literature in six sentences
***INPUT***
the input is a biomedical literature
***OUTPUT***
the output is the summary of an input biomedical literature in six sentences
***DOCUMENTATION***
***EXAMPLES***
Input: abdominal muscle strengthening exercises are frequently used for the promotion of health
and prevention of musculoskeletal disease , as well as for rehabilitation of lower back
pain1 , 2 .
strengthening the abdominal muscles helps to stabilize the trunk
and lessen the stress on the lumbar spine3 .
the curl - up exercise has been shown to produce reasonable levels of
activity in the rectus abdominis ( ra ) muscle while minimizing the resultant load on the
spine4 .
however , the curl - up exercise may activate the superficial cervical flexors , such as the
sternocleidomastoid ( scm ) , because the head and shoulders are raised off the floor during
the neck flexion .
superficial cervical flexors are the dominant muscle group during neck
flexion movement5 . a neck flexion position
that causes neck pain could be a contributing factor to increased back pain , because the
vertebral regions are connected to each other6 .
according to lee et al.7 the activity of the scm muscle increases as the neck flexion angle
increases .
muscle activity of the superficial neck flexor is significantly increased in
cervical pain during the neck stabilizing task ; increased activity of the scm could be
compensatory for poor segmental stability of the deep muscles .
therefore , an intervention to
decrease scm activity with neck flexion restriction during the curl - up exercise is
required .
research has focused primarily on increased abdominal activity during curl - up exercises
using an unstable surface8 and different
positions of the upper and lower limbs9 to
identify the most effective position to increase abdominal strength . the question of whether
neck flexion restriction can alter the muscle activity of the ra , external oblique ( eo ) , and
scm muscles during a curl - up has not been investigated .
thus , the purpose of this study was
to assess the effect of neck flexion restriction on scm and abdominal muscle activity during
the traditional curl - up exercise and the curl - up exercise with neck flexion restriction .
in total , 13 healthy male subjects were recruited from inje university , gyeongsangnam - do ,
republic of korea .
the mean age of the subjects was 23.7 0.4 years , and their mean height
and weight were 173.2 5.25 cm and 66.5 5.7 kg , respectively .
subjects were excluded if
they had a history of abdominal or low - back pain within 6 weeks prior to the study and an
inability to correctly perform all the exercises in a pain - free manner .
prior to
participation , all subjects read and signed an informed consent form that was approved by
the institutional research review committee of inje university .
surface electromyographic ( emg ) signals were collected with a trigno wireless emg system
( delsys , inc . ,
emg data were collected from the scm , ra , and eo muscles on
the dominant side .
the electrode placements were as follows : scm , half the distance between
the mastoid process and the sternal notch ; ra , 2 cm lateral to the umbilicus ; and eo , the
inferior edge of the eighth rib superolateral to the costal margin10 .
root mean square values were calculated for all raw data .
to normalize the data , the maximum voluntary isometric contraction ( mvic ) of each muscle
the subject was instructed to lay supine with both arms down
by their side , knees flexed to approximately 90 , hips flexed to approximately 45 , and feet
placed flat on the floor .
subjects elevated their trunk by lifting their head and shoulders
until the scapulae were lifted above the floor .
a target bar was placed at the chest to
provide feedback when the scapulae were off the floor .
second , subjects performed a
traditional curl - up exercise with neck flexion restriction .
the subject began in a supine
hook - lying position and was asked to move to the chin tuck position .
lightly touch your right hands on your mandible to provide a tactile cue for
neck flexion restriction during curl - up .
the subject was asked to touch the target bar
during each curl - up exercise and to hold the position for 5 s. all test trials were repeated
three times , with a 1-min rest between trials to avoid fatigue .
the mean value of these
measurements was used for data analysis . to compare the differences in normalized emg muscle activity of the scm , ra , and eo
muscles , between the traditional curl - up and curl - up with neck flexion restriction
exercises ,
there was significantly lower emg activity of the scm during the curl - up exercise with neck
flexion restriction than the traditional curl - up exercise ( p < 0.05 ) .
conversely , the
activity of the ra and eo muscles was significantly higher during the curl - up exercise with
neck flexion restriction compared to the traditional curl - up exercise ( p < 0.05 ; table 1table 1.electromyography activity ( % maximum voluntary isometric contraction ) in the
sternocleidomastoid , rectus abdominis , and external oblique muscles during the
traditional curl - up and curl - up with neck flexion restriction exercisesmuscletraditional curl - upcurl - up with neck flexion restrictionsternocleidomastoid32.2 4.5 * 22.1 6.1rectus abdominis46.5 12.356.2 11.1*external oblique38.8 15.550.4 17.8**p<0.05 ) .
the results of this study showed that the curl - up exercise with neck flexion restriction
decreased the activity of the scm muscle and increased the activity of the abdominal muscles
significantly .
this may have important clinical implications for abdominal muscle
strengthening in patients with neck pain . in this study
, we showed that during the curl - up exercise in which neck flexion was
restricted by the subject s hand , the muscle activity of the scm was decreased compared to
the traditional curl - up exercise .
recently , a self - monitored method using tactile
stimulation through the subject s own finger touching has been shown to be a useful clinical
method to enhance abdominal muscle training and to prevent compensatory movement12 .
superficial cervical flexors ( scm and
anterior scalenes ) contribute to forward translator motion in the cervical region5 .
considering the significantly decreased scm
activity in this study , having subjects touch their hands on the mandible could be a good
strategy to prevent forward translation in the cervical region .
previous studies focused on decreased scm and increased abdominal activity during the
curl - up exercise13 , 14 .
yoon et al.14
reported that the muscle activity of scm during curl - up with craniocervical flexion ( ccf )
was significantly lower than during the traditional curl - up exercise , but the abdominal
muscle activity did not differ between the two tasks .
however , we found that decreased scm
activity could influence increased abdominal muscle activity during curl - up with neck
flexion restriction .
it is possible that neck flexion restriction by the subject s hand
( scm : 22.1%mvic ) could be used to greatly reduce cervical curve flexion relative to ccf
( right scm : 39.5 , left scm : 38.2%mvic ) due to decreased scm activity .
thus , reduced cervical
flexion during the curl - up exercise with neck flexion restriction could increase abdominal
muscle activity because of the lengthened lever arm of the trunk .
further studies are needed to
assess not only the activity of the abdominal muscle , but also kinematic data in the
cervical region .
this study provides empirical evidence that the curl - up exercise in which neck flexion is
restricted by the hand is more useful for enhancing abdominal muscle activity compared to
the traditional curl - up exercise .
this suggests that it may be used as an alternative
abdominal strengthening exercise for the management of patients with neck disability .
therefore , the curl - up exercise with neck flexion restriction is recommended to prevent
excessive activation of the superficial cervical flexors during the curl - up exercise .
Output:
| [ purpose ] the purpose of this study was to investigate the effect of neck flexion
restriction on sternocleidomastoid ( scm ) , rectus abdominis ( ra ) , and external oblique ( eo )
muscle activity during a traditional curl - up exercise and a curl - up with neck flexion
restriction .
[ subjects ] in total , 13 healthy male subjects volunteered for this study .
[ methods ] all subjects performed a traditional curl - up exercise and a curl - up exercise in
which neck flexion was restricted by the subject s hand
. surface electromyography ( emg )
signals were recorded from the scm , ra , and eo during the curl - up .
[ results ] there was
significantly lower emg activity of the scm during the curl - up exercise with neck flexion
restriction compared to the traditional curl - up exercise .
conversely , the activity of the
ra and eo muscles was significantly higher in the curl - up exercise with neck flexion
restriction than in the traditional curl - up exercise .
[ conclusion ] neck flexion
restriction is recommended to prevent excessive activation of superficial cervical flexors
during the curl - up exercise . |
PubmedSumm6552 | ***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: lung cancer has been the leading cause of cancer - related deaths in korea , and its incidence continues to rise . despite therapeutic advances , the overall 5-year survival remains only 15% .
lung cancer is a multicellular and multistage process that involves a number of genetic changes in oncogenes and tumor suppressor genes .
nevertheless , the prognosis of lung cancer has remained poor despite innovations in diagnostic testing and surgical technique and the development of new chemotherapeutic agents .
recently introduced targeted agents show different responses according to histological subtype , and the efficiency of treatment modalities for lung cancer depends on the time of diagnosis .
therefore , there is a great need for rapid and efficient early detection methods . for developing improved molecular biomarkers for the early detection and prediction of response to chemotherapy
, it is important to identify genetic alterations specific to each subtype of lung cancer .
single - nucleotide polymorphisms ( snps ) represent an important class of genetic variations and affect an individual 's susceptibility to disease in certain circumstances [ 4 - 6 ] .
activation of the intracellular survival signal transduction protein akt , known as protein kinase b , has been proposed as a central signaling event in carcinogenesis and has been shown in experimental models to confer resistance to chemotherapy and radiation [ 7 , 8 ] .
akt is activated by phosphatidylinositol 3 phosphates , the products of phosphoinositide 3-kinase ( pi3k ) activity .
additionally , akt activity is commonly dysregulated in a variety of human tumors because of frequent inactivation of the pten tumor suppressor gene , which negatively regulates phosphatidylinositol 3 phosphate levels , and alterations of this gene have been identified in various cancers , including lung cancer [ 10 , 11 ] . to date , 3 human isoforms of akt have been identified , akt1 , akt2 , and akt3 , which are expressed in lung , breast , colon , and prostate tumor tissues .
somatic mutations of akts have been reported in endometrial carcinomas , hypoglycemia , and breast cancer [ 13 , 14 ] .
however , somatic mutations in akt families are rare in lung cancer [ 15 , 16 ] .
previously , it was reported that an akt1 polymorphism was not associated with schizophrenia [ 17 , 18 ] .
akt1 and akt2 polymorphisms have been reported to be related to survival of esophageal cancer , and it was reported that an akt1 polymorphism was associated with survival in surgically resected non - small cell lung cancer . however , the association between akt2 and akt3 polymorphisms and the risk of lung cancer has not yet been clarified .
this study discovered polymorphisms of the akt2 and akt3 promoter regions and their relation with the risk of lung cancer in a korean population .
between august 2001 and november 2010 , blood samples were collected from 720 subjects , including 360 lung cancer patients and 360 normal controls without cancer .
lung cancer patients were recruited from the patient pool at the genomic research center for lung and breast / ovarian cancer , and control subjects were randomly selected from a pool of healthy volunteers who had visited the cardiovascular genome center and genomic research center for allergy and respiratory diseases .
detailed information on diet , smoking status , drinking status , lifestyle , and medical history were collected by trained interviewers using a structured questionnaire .
out of 360 cases , information was available for 352 on smoking status , 317 on stage , and 343 on cell type , while information was available for 272 on smoking status of 360 controls .
all study subjects provided written consent and were ethnic koreans , and all participating institutional review boards approved the study protocol .
genomic dna was prepared from peripheral blood samples using a puregene blood dna kit ( gentra , minneapolis , mn , usa ) , following the manufacturer 's protocol . to identify polymorphisms in the promoter of the akt2 and akt3 genes , human genomic dna was isolated from the whole blood of 24 lung cancer patients for direct sequencing , and the promoter region of the akt2 and
polymerase chain reaction ( pcr ) amplifications were performed on a ptc-225 peltier thermal cycler ( mj research inc . ,
waltham , ma , usa ) using ampli - taggold ( roche , branchburg , nj , usa ) .
all amplifications were performed using 35 cycles of 30 s at 95 , 1 min at 64 , and 1 min at 72 , followed by a single 10-min extension at 72. pcr products were purified using the montage pcr96 cleanup kit ( millipore , bedford , ma , usa ) and eluted in 20 l of nuclease - free h2o .
dna cycle sequencing was carried out using the bigdye terminator v 3.1 cycle sequencing kit ( perkin elmer , foster city , ca , usa ) .
multiscreen seq 384-well filter plates were used for dye removal , and sequences were then analyzed on an applied biosystems 3700 ( abi , foster city , ca , usa ) .
all polymorphisms and sequence alignments were analyzed using polyphred . after direct sequencing of the akt2 and akt3 genes , we performed genotyping for the 8 polymorphisms of the akt2 and akt3 genes .
the genotypes of the akt2 and akt3 polymorphisms were screened by taqman fluorogenic 5 ' nuclease assay ( abi ) .
the final volume of the pcr was 5 l , containing 10 ng of genomic dna , and 2.5 l taqman universal pcr master mix , with 0.13 l of 40 assay mix .
thermal cycle conditions were as follows : 50 for 2 min to activate uracil n - glycosylase and prevent carryover contamination , 95 for 10 min to activate the dna polymerase , and 45 cycles of 95 for 15 s and 60 for 1 min .
all pcrs were performed using 384-well plates on a dual 384-well geneamp pcr system 9700 ( abi ) , and the endpoint fluorescent readings were performed on an abi prism 7900 ht sequence detection system ( abi ) . duplicate samples and negative controls were included to ensure accuracy of genotyping .
allele frequencies , genotype frequencies , and departures of genotype distributions from hardy - weinberg equilibrium ( hwe ) for each snp were analyzed using chi - square test or fisher 's exact test .
linkage disequilibrium ( ld ) was tested on pairwise combinations of polymorphisms using the absolute value of the standardized measure of ld , d ' , calculated by haploview version 3.2 .
genotype - specific risks were estimated as odds ratios with associated 95% confidence intervals by unconditional logistic regression ( sas institute inc . , cary , nc , usa ) and adjusted for age , gender , and smoking status .
between august 2001 and november 2010 , blood samples were collected from 720 subjects , including 360 lung cancer patients and 360 normal controls without cancer .
lung cancer patients were recruited from the patient pool at the genomic research center for lung and breast / ovarian cancer , and control subjects were randomly selected from a pool of healthy volunteers who had visited the cardiovascular genome center and genomic research center for allergy and respiratory diseases .
detailed information on diet , smoking status , drinking status , lifestyle , and medical history were collected by trained interviewers using a structured questionnaire .
out of 360 cases , information was available for 352 on smoking status , 317 on stage , and 343 on cell type , while information was available for 272 on smoking status of 360 controls .
all study subjects provided written consent and were ethnic koreans , and all participating institutional review boards approved the study protocol .
genomic dna was prepared from peripheral blood samples using a puregene blood dna kit ( gentra , minneapolis , mn , usa ) , following the manufacturer 's protocol . to identify polymorphisms in the promoter of the akt2 and akt3 genes ,
human genomic dna was isolated from the whole blood of 24 lung cancer patients for direct sequencing , and the promoter region of the akt2 and akt3 genes was amplified .
polymerase chain reaction ( pcr ) amplifications were performed on a ptc-225 peltier thermal cycler ( mj research inc . ,
waltham , ma , usa ) using ampli - taggold ( roche , branchburg , nj , usa ) .
all amplifications were performed using 35 cycles of 30 s at 95 , 1 min at 64 , and 1 min at 72 , followed by a single 10-min extension at 72. pcr products were purified using the montage pcr96 cleanup kit ( millipore , bedford , ma , usa ) and eluted in 20 l of nuclease - free h2o .
dna cycle sequencing was carried out using the bigdye terminator v 3.1 cycle sequencing kit ( perkin elmer , foster city , ca , usa ) .
multiscreen seq 384-well filter plates were used for dye removal , and sequences were then analyzed on an applied biosystems 3700 ( abi , foster city , ca , usa ) . all polymorphisms and sequence alignments were analyzed using polyphred .
after direct sequencing of the akt2 and akt3 genes , we performed genotyping for the 8 polymorphisms of the akt2 and akt3 genes .
the genotypes of the akt2 and akt3 polymorphisms were screened by taqman fluorogenic 5 ' nuclease assay ( abi ) .
the final volume of the pcr was 5 l , containing 10 ng of genomic dna , and 2.5 l taqman universal pcr master mix , with 0.13 l of 40 assay mix .
thermal cycle conditions were as follows : 50 for 2 min to activate uracil n - glycosylase and prevent carryover contamination , 95 for 10 min to activate the dna polymerase , and 45 cycles of 95 for 15 s and 60 for 1 min . all pcrs were performed using 384-well plates on a dual 384-well geneamp pcr system 9700 ( abi ) , and the endpoint fluorescent readings were performed on an abi prism 7900 ht sequence detection system ( abi ) .
allele frequencies , genotype frequencies , and departures of genotype distributions from hardy - weinberg equilibrium ( hwe ) for each snp were analyzed using chi - square test or fisher 's exact test .
linkage disequilibrium ( ld ) was tested on pairwise combinations of polymorphisms using the absolute value of the standardized measure of ld , d ' , calculated by haploview version 3.2 .
genotype - specific risks were estimated as odds ratios with associated 95% confidence intervals by unconditional logistic regression ( sas institute inc . , cary , nc , usa ) and adjusted for age , gender , and smoking status .
all the clinical characteristics , except for smoking status , were not significantly different between the cases and controls .
this difference of smoking status was controlled in the multiple logistic regression analysis , adjusted for age , gender , and smoking status . by direct sequencing of the akt2 promoter region in 24 lung cancer patient samples , we identified 1 novel polymorphism ( -9826 c / g ) and 4 known polymorphisms ( -9473 c / t , -9151 c / t , -9025 c / t , and -8618 g / a ) .
also , we identified 1 novel polymorphism ( -811 a / g ) and 2 known polymorphisms ( -675 a/- and -244 c / t ) by direct sequencing in the akt3 promoter region ( table 2 ) .
however , the ld and haplotype block in akt3 polymorphisms were unidentified because of the low frequency of the akt3 - 811 g allele and akt3 - 244 t allele ( 2.1% and 2.2% , respectively ) ( fig .
further analyses were then performed on the samples from 460 lung cancer patients and 460 controls .
association of lung cancer risk with akt polymorphisms was then analyzed , revealing no association of the polymorphisms with the risks of lung cancer ( table 3 ) .
the association of the polymorphisms with the risk of lung cancer was further examined after stratifying the subjects according to gender and smoking status .
furthermore , the haplotypes of the akt2 polymorphisms were not associated with the risks of lung cancer in 3 alternative models ( data not shown ) .
v - akt murine thymoma viral oncogene homolog ( akt ) is a serine / threonine protein kinase that is activated by pi3k- and mediates pi3l signaling . a major recurrent mutation ( glu17lys ) in the akt1 gene , which encodes protein kinase b , has been identified in several solid tumors , including breast , colon , and ovarian cancers .
overall , the frequency of akt1 mutations in non - small cell lung carcinoma ( nsclc ) is about 1% , and they have only been identified in squamous cell carcinoma .
also , mutations in the akt2 and akt3 genes are rare in several tumors , including lung cancer .
recently , several polymorphisms in the akt1 gene have been reported in relation to human disease [ 24 - 26 ] .
kim et al . first reported that the akt1 polymorphisms could be used as prognostic markers for patients with early - stage nsclc .
however , there has been no study on the association between lung cancer risk and polymorphisms of akt2 and akt3 . in this study , we investigated the association between akt2 and akt3 polymorphisms and the risk of lung cancer in the korean population .
the genotypes and haplotypes of the akt2 and akt3 genes were determined in 720 koreans to evaluate the role of the akt2 and akt3 polymorphisms in the risk of lung cancer ; however , the results revealed no significant difference between lung cancer patients and normal controls .
also , by tfsearch ( version 1.3 ) analysis of the akt2 and akt3 polymorphism regions , the location of these variants did not have sequences for transcription factor binding sites .
this result suggests that polymorphisms of the akt2 and akt3 promoter region are unlikely to play an important role in the susceptibility to lung cancer .
, we observed the frequencies of 5 polymorphisms in the akt2 promoter region , and we observed frequencies of 3 polymorphisms in the akt3 promoter region in 24 korean populations using direct sequencing . in the direct sequencing result , we detected no frequencies in another known polymorphisms ( akt2 : rs11666690 , rs11665880 , rs35814223 , rs34408497 , rs35408040 , rs10418387 ; akt3 : rs11588441 , rs6679386 , rs41267521 ) .
the frequencies of akt2 promoter polymorphisms showed similar frequencies in the asian ethnic groups ( han chinese and japanese ) of the dbsnp database ( www.ncbi.nlm.nih.gov/snp ) .
the frequency of the minor allele of rs35835614 in the akt3 gene was 0.275 ; however , the frequency of this polymorphism has not been reported in the dbsnp database ( www.ncbi.nlm.nih.gov/snp ) .
a series of our previous studies showed that polymorphisms of oncogenes , tumor suppressor genes , and receptor tyrosine kinases are related to lung cancer risk [ 6 , 28 , 29 ] .
recently , we reported that stk11 and pik3ca polymorphisms are not related to genetic susceptibility to lung cancer [ 30 , 31 ] .
the genotypes of the akt2 and akt3 promoter polymorphisms , determined in 720 koreans in the present study , revealed no significant difference between lung cancer patients and normal controls . to our best knowledge , this is the first study on the association of akt2 and akt3 promoter polymorphisms and the risk of lung cancer in a korean population .
Output:
| akt is a signal transduction protein that plays a central role in the tumorigenesis .
there are 3 mammalian isoforms of this serine / threonine protein kinase - akt1 , akt2 , and akt3-showing a broad tissue distribution .
we first discovered 2 novel polymorphisms ( akt2 -9826 c / g and akt3 -811 a / g ) , and we confirmed 6 known polymorphisms ( akt2 -9473 c / t , akt2 -9151 c / t , akt2 -9025 c / t , akt2 -8618g / a , akt3 -675 a/- , and akt3 -244 c / t ) of the akt2 and akt3 promoter region in 24 blood samples of korean lung cancer patients using direct sequencing . to evaluate the role of akt2 and akt3 polymorphisms in the risk of korean lung cancer , genotypes of the akt2 and akt3 polymorphisms ( akt2 -9826 c / g , akt2 -9473 c / t , akt2 -9151 c / t , akt2 -9025 c / t , akt2 -8618g / a , and akt3 -675 a/- ) were determined in 360 lung cancer patients and 360 normal controls .
statistical analyses revealed that the genotypes and haplotypes in the akt2 and akt3 promoter regions were not significantly associated with the risk of lung cancer in the korean population .
these results suggest that polymorphisms of the akt2 and akt3 promoter regions do not contribute to the genetic susceptibility to lung cancer in the korean population . |
PubmedSumm6553 | ***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: electrocardiogram ( ecg ) is an important diagnostic tool for the prompt recognition of myocardial infarction ( mi ) .
identification of st elevation mi by ecg in the critically ill patient population is limited by the lack of specificity due to a variety of non - ischemic processes .
this is a case report of a 77-year - old male patient who presented with generalized weakness , confusion , somnolence , recurrent falls and tea - colored urine for 3 - 4 days .
his past medical history was significant for hypertension , chronic obstructive pulmonary disease and coronary artery disease with a remote history of mi .
his vitals showed blood pressure 97/42 , heart rate of 51 , respiratory rate of 12 and oxygen saturation of 93% on room air .
there were extensive ecchymoses in different stages of healing on all 4 extremities and on the torso .
baseline electrocardiogram during admission to the hospital the patient was rehydrated with intravenous normal saline and nephrotoxic medications were withheld .
his renal function improved and on the 2 day , his chest x - ray revealed patchy bilateral infiltrates . on the 3 day , he developed respiratory distress with an increase in oxygen requirements .
the chest computed tomography revealed bilateral ground glass opacities with consolidation consistent with acute lung injury / acute respiratory distress syndrome . after failing a trial of
non - invasive positive pressure ventilation , he was intubated and mechanically ventilated for hypoxic respiratory failure .
he developed intermittent supraventricular tachycardia , atrial flutter and atrial fibrillation were treated with intravenous esmolol and diltiazem after which he converted to sinus rhythm . on the 4 hospital day , he developed increasing oxygen requirements and asynchronous volume control ventilation ; his ventilator settings were switched to pressure control ventilation .
an echocardiogram revealed left ventricular ejection fraction of 45 - 50% with grade ii diastolic dysfunction and no wall motion abnormalities .
he later became progressively hypoxic and tachypneic on the ventilator during the next couple of days .
his clinical status worsened and his ventilator settings were changed ; the positive end - expiratory pressure ( peep ) was increased to 13 mm hg .
ecg at the time showed st segment and t wave changes concerning for st elevation mi .
careful review of the ecg revealed bizarre , broad - based apparent st - segment elevation in the precordial leads where the upward shift of the baseline started slightly before the onset of the qrs complexes .
a more obvious dome and spike pattern was seen in the inferior leads [ figure 2 ] .
his central venous pressure decreased from 12 to 7 mm hg and tidal volumes were increased from 550 to 750 cc during this period .
an urgent bedside echocardiogram showed preserved left ventricular ejection fraction with no wall motion abnormalities .
the patient passed away on the 11 day of hospitalization from acute respiratory distress syndrome .
st - t segment changes of precordial leads after increase in positive end - expiratory pressure to 13 mm hg .
german military helmet with dome and spike ( inset ) reproduced with permission from mayo clinic proceedings resolution of st - t segment changes in precordial leads after the discontinuation of positive end - expiratory pressure
our case represents an uncommon finding of dome and spike st - t wave changes mimicking st elevation mi in the setting of a critical non - cardiac illness .
these findings were similar to those reported by littmann and monroe and tomcsnyi et al .
the st - t wave changes in these cases were likened to a spiked german military helmet [ inset figure 2 ] the pickelhaube , introduced in 1842 by friedrich wilhelm iv , the king of prussia .
the mechanism of this phenomenon is unknown and several postulated mechanisms for this finding include ( 1 ) artifact ( 2 ) a sudden increase in the intra - abdominal or intra - thoracic pressure ( 3 ) direct stimulation of inferior wall of left ventricle by the diaphragm , ( 4 ) stimulation of the diaphragm by the left phrenic nerve , ( 5 ) synchronized contraction of diaphragm along with the cardiac cycle in the setting of alkalosis with latent tetany , ( 6 ) acute stretch of skin overlying the chest wall with each cardiac cycle and ( 7 ) diaphragmatic breathing that alters ecg patterns .
the acute rise in intrathoracic pressure with an increase in peep most likely contributed to the dome and spike pattern in our patient .
this abnormal ecg finding with a dome and spike helmet sign pattern in a critically ill patient is a marker for very high mortality .
it is an under - recognized phenomenon and further research is needed as early recognition can possibly assist clinical management .
Output:
| a 77-year - old male patient presented with rhabdomyolysis .
he developed progressive respiratory failure and acute respiratory distress syndrome during his hospital stay requiring mechanical ventilation .
an electrocardiogram during mechanical ventilation showed findings suggestive of st elevation myocardial infarction .
closer review showed dome and spike findings that have been likened to a spiked helmet .
this finding has been associated with significant mortality .
we discuss this under - recognized finding and the potential contributing mechanisms . |
PubmedSumm6554 | ***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 about 45 bc , hippocrates used the words mania and melancholia to describe mental disorders .
mood disorders , especially depression , are among the most common mental disorders of adults , in which the individuals involvement during their lifetime is estimated to be 10 - 25% .
numerous factors including biological , psychological , and social elements influence the incidence of depression .
constant pain and suffering and hopelessness , not enjoying the most joyful events , and loss of interest in visiting family members and friends or to go to work or to have other leisure time activities are among the signs of depression .
its other signs include existence of negative thoughts including feeling of not being worthy , sinfulness , hopelessness , and even suicidal thoughts .
depression can be a disabling disorder , and most of the types of depression can be successfully treated by timely diagnosis and medication or psycho therapy , so that their recurrence onset can be prevented .
mentally retarded children , whose presence is a disturbing factor for family 's normal condition , act as a very important and effective stressor , which can threaten familial mental health .
studies show that existence of a mentally retarded child in a family can result in special problems and concerns for other family members .
in researches investigating and comparing the level of depression in mothers of mentally retarded children with that of mothers with healthy children , a notable percentage of depression was reported among mothers of the former group .
the families who take care of their mentally retarded children at home are surrounded by various problems to different extent .
detection of their problems and their related factors can be used by supportive organizations for providing support and guidance of these families . since the health of mothers is considered the main core of the family in all societies , and due to the importance of health of mothers with mentally retarded children in making use of existing potentialities among these children , their mental problems should be essentially assessed .
therefore , the present study was conducted with the goal of investigating the level of depression and its related factors among the mothers with mentally retarded children , who were exceptional girls of primary schools in isfahan .
it is hoped to design an educational program to improve the health and quality of life of the mothers involved in taking care of a mentally disabled child , through the results of this research .
this is a cross - sectional study conducted on 120 mothers of mentally retarded children in primary exceptional girls schools of isfahan in the school year 2012 - 2013 .
simple size was calculated to be 120 based on the existing files on girls of exceptional primary schools ( a total of eight schools ) and considering p = 0.5 and an accuracy of 0.05 .
data were collected by a questionnaire including two sections of personal characteristics and beck standard depression scale , for which the validity had been confirmed in iran .
this scale is used to measure the intensity of depression and includes 21 questions scored based on the likert 's scale ( 0 - 3 ) . its reliability was reported as 0.73 and its cronbach 's alpha was 0.90 .
scores 1 - 10 were assigned to healthy individuals , 11 - 17 to minor depression , 18 - 29 to moderate depression , and scores > 30 were assigned to major or acute depression .
the qualified subjects completed personal characteristics questionnaire and beck depression scale . if the selected student was not qualified to be included or her mother did not cooperate with the researcher , a new subject was randomly selected .
mothers with depression already diagnosed and undergoing treatment were excluded from completion of the depression questionnaire . after the questionnaires were completed , the results were analyzed by spearman , mann - whitney , and kruskal - wallis tests through spss .
this is a cross - sectional study conducted on 120 mothers of mentally retarded children in primary exceptional girls schools of isfahan in the school year 2012 - 2013 .
simple size was calculated to be 120 based on the existing files on girls of exceptional primary schools ( a total of eight schools ) and considering p = 0.5 and an accuracy of 0.05 .
data were collected by a questionnaire including two sections of personal characteristics and beck standard depression scale , for which the validity had been confirmed in iran .
this scale is used to measure the intensity of depression and includes 21 questions scored based on the likert 's scale ( 0 - 3 ) . its reliability was reported as 0.73 and its cronbach 's alpha was 0.90 .
scores 1 - 10 were assigned to healthy individuals , 11 - 17 to minor depression , 18 - 29 to moderate depression , and scores > 30 were assigned to major or acute depression .
the qualified subjects completed personal characteristics questionnaire and beck depression scale . if the selected student was not qualified to be included or her mother did not cooperate with the researcher , a new subject was randomly selected .
mothers with depression already diagnosed and undergoing treatment were excluded from completion of the depression questionnaire . after the questionnaires were completed , the results were analyzed by spearman , mann - whitney , and kruskal - wallis tests through spss .
in the present study , 120 mothers of age 28 - 50 years with a mean age of 40.08 5.3 years and with mentally retarded children were investigated .
( n = 33 ) were working . the highest frequency distribution with regard to mothers education , i.e. 78.4% , was for high school diploma or less ( n = 94 ) .
the age of their children ranged 6 - 23 years with a mean of 13.7 3.4 years .
their spouses age ranged 30 - 62 years with a mean of 44.8 6.7 years .
the highest frequency distribution with regard to fathers education ( 73.3% ) was for high school diploma or less .
about 4.2% of the spouses were jobless , 55% were employees , 32.5% were self - employed , and 8.3% were laborers .
the length of marriage of the mothers under study ranged 14 - 38 years with a mean of 20.02 6.7 years .
the results showed that 75% of these mothers had various degrees of depression ( 25.8% had minor depression , 24.2% had moderate depression , and 25% had major depression ) .
there was no significant association between mothers occupation and the intensity of depression ( z = 0.58 , p = 0.56 ) . in mothers whose spouses were unemployed or laborer s , the intensity of depression was significantly higher , compared to the mothers whose spouses were employees or self - employed ( = 9.84 , p = 0.02 ) .
spearman coefficient showed a direct association between mothers depression and students age ( r = 0.258 , p = 0.005 ) , mothers age ( r = 0.186 ,
p = 0.04 ) , fathers age ( r = 0.362 , p = 0.004 ) , the number of children ( r = 0.003 , p = 0.265 ) , and the length of marriage ( r = 0.259 , p = 0.004 ) , and an inverse association with fathers education ( r = 0.336 , p = 0.000 ) and mothers education ( r = 0.222 , p = 0.015 ) [ table 1 ] . variables in mothers with mentally retarded children with and without depression about 26.7% of the women had married their relatives and 6.7% mentioned a history of a genetic disease in their families .
none of the mothers mentioned any history of maternal diseases and consumption of a specific medication during their pregnancies .
about 42.5% of the pregnancies were unwanted , and 14.2% of children were taking medication under the supervision of a physician at the time of the study .
there was no significant association between familial marriage and the intensity of mothers depression , as well as between existence of a genetic disease and mothers depression ( z = 0.41 , p = 0.68 ) .
there was a significant association between wanted pregnancy and the intensity of mothers depression , as 41% of mothers with an unwanted pregnancy experienced various degrees of depression and just 10% of these mothers had no depression ( z = 1.98 , p = 0.048 ) .
there was no significant association between depression during pregnancy and mothers depression intensity ( z = 0.04 , p = 0.97 ) [ table 2 ] .
related factors in mothers with mentally retarded children with and without depression table 2 shows that there was no significant association between consumption of medication by the child and mothers intensity of depression ( z = 0.626 , p = 0.532 ) . with regard to adequacy of spouses and
families mental and psychological support , 33.3% of mothers believed that the support was not adequate .
results showed a significant inverse association between adequate spouses and families mental and psychological support and the intensity of mothers depression ( z = 4.89 , p < 0.001 ) . in the group where spouses and families mental and psychological support was believed to be adequate , depression of different degrees was found in 62.4% , while in the group where it was not believed to be adequate , this value was 100% , with a notable difference ( 37.6% ) compared to the first group .
intensity of depression was significantly higher in mothers with mentally retarded children compared to that in mothers with children having down syndrome ( z = 4.28 , p < 0.001 ) .
the obtained results show that prevalence of various degrees of depression among the mothers with mentally retarded children was higher ( 75% ) than that among the other women in the society .
one researcher in iran reported 34.2% of population suffered from mental disorders ( 37.9% in women and 28.6% in men ) .
mohamadi et al . reported the prevalence of major depression among women in isfahan as 5.57% and the total prevalence of mood disorders in women of isfahan as 8.44% .
as observed in the present study , prevalence of total depression among women was higher in isfahan .
this reveals that women with mentally retarded children are more prone to depression due to the different conditions they are in , compared to the other members of the society .
mohamadi et al . reported in their study that 76.7% of these mothers suffered from acute mental problems and depression .
mohamadkhan kermanshahi et al . pointed to a high prevalence of depression and other mental problems among these mothers ( 50% ) . in this direction ,
kouhestani and mirzamani stated that mothers with mentally retarded children are more prone to develop depression , compared to mothers with healthy children .
our study also revealed that 75% of the mothers with mentally retarded children had various degrees of depression .
25.8% had minor depression , 24.2% had moderate depression , and 25% had major depression .
research shows that in general , mothers of mentally retarded children have unstable emotional states , psychological diseases , resistant sorrow , social isolation and , eventually , depression . in relation with education
, it was observed that with an increase in the level of education , mothers depression intensity decreased , which can be possibly due to their increased awareness and knowledge . on the other hand ,
increase in awareness of the families enhances their referral to educational and counseling centers and they acquire the correct approach toward these children and the way to educate them , which decreases their concern , anxiety and , consequently , their depression . through passing higher degrees of education ,
the mothers try to have a more appropriate attitude and perception , which are combined with empowerment of the children 's abilities and positive potentialities through time and results in children 's condition getting better , which ultimately diminishes mothers depression .
moosavi khatat indicated that mothers sometimes have to leave their education unfinished due to them being involved in numerous caring needs of their children and devoting all their time to their children 's care , which leads to the worsening of their depression .
harris also reported that the mothers with low education and belonging to low socioeconomic condition had more tension due to their direct responsibility for such children and their related care , as well as tolerating their conditions .
no significant association was observed between mothers occupation and their depression . in the family where a mentally retarded child exists , having a job is of high importance for the mother as it can affect various dimensions of her life .
women 's working , despite allowing them to spend only fewer hours of their time at home , improves families economic status and causes changes in the management and family members roles .
although primarily this effect results in a change in the spouse 's function and decrease of his power , finally in many cases , it leads to better coordination between spouses in decision making and management of their common life . with regard to the association between spouses occupation and mothers depression , the intensity of depression was significantly more among the mothers whose spouses were unemployed or laborer s , compared to those whose spouses were employees or self - employed . in this relation ,
amiri et al . pointed out that lower income of a family increases the stress imposed on it and , consequently , increases the incidence of depression .
it can be noted that occupation is a key element in the incidence of depression , as a higher family income brings about more financial and mental security for the mother . on the contrary , low financial status of the family
may worsen the already existing depression in case of having a mentally retarded child , which was not possible to be investigated and controlled in the present study and needs to be studied further . in relation with
the association between mothers wanted pregnancy and their intensity of depression , there was a significant difference , such that only 10% of these mothers did not suffer from depression . in this case , either unwanted pregnancy may itself be the cause of the depression , which is made more severe by existence of a mentally retarded child , or the report of an unwanted pregnancy is masked by the child 's mental disability .
there was no significant association between medication consumption of the mentally retarded children and their mothers depression in the present study .
on the one hand , the child 's medication , followed by an improvement in his / her condition , can positively affect the family 's mental conditions and , consequently , positively influence the intensity of the mother 's depression .
on the other hand , children 's medication may make the mothers believe their children 's condition is so acute that they have to take mediation , and it may cause anxiety among mothers .
therefore , depending on the attitudes and approaches of the mothers concerning their children 's medication , as well as the effect of medication on the children 's condition , the intensity of depression may vary . as this issue has not been adequately studied in the present study ,
results showed a direct association between mothers depression intensity and students age , mothers age , fathers age , the number of children , and the length of marriage .
reported that the child 's age is associated with parents stress and mental health , as the stress and mental pressure , related to the child 's cognitive defect , disappear with increase of his / her age .
claimed that there was no association between the child 's mother 's and father 's age and mother 's social adaptation and depression .
they also showed that there was no association between mothers depression , and the length of marriage and the number of children .
the results showed that 33.3% of the subjects did not believe that spouses and friends mental support was adequate , although a direct significant association was observed between adequate mental support from spouses and friends and the intensity of mothers depression .
depression of different degrees was observed in 62.4% of the group which believed that spouses and friends support was adequate , while in the group which did not believe so , most of the mothers had a notable difference of 37.6% , which was consistent with mohamadkhan kermanshahi et al .
one of the social determinants of health which points out the importance of social dimension of human beings and has been increasingly noted in recent years is social support .
there are notable evidences which show that social support plays a key role in the health of individuals in a society , and that social isolation results in a disease .
spouses and friends mental support is a part of social support , which is a very important factor in the prevention of depression .
since the level of depression was 100% among the mothers who believed the support was not adequate , it can be noted that those who are not mentally supported develop more severe depression .
mohamadkhan kermanshahi et al . mentioned that most of these mothers are not adequately provided with mental support from their spouses and friends , which worsens their mental disorders including depression .
this problem can be solved by life skills education through educational programs , so as to take steps toward the reduction of depression among these mothers . in relation with the association between existence of depression in mothers immediate family members and their own depression
, it can be argued that an immediate family member with depression may cause depression in mothers due to genetics or shortage of adequate support received from the related family member or friend .
consequently , the mothers lack support and feel lonely and helpless in taking care of their mentally retarded child . on the other hand , existence of depression in an immediate family member
can impose an extra source of anxiety to the mothers , in addition to their already existing stress and problems related to taking care of a mentally retarded child , which eventually leads to the worsening of their depression .
results showed that the intensity of depression was significantly higher in the mothers with mentally retarded children , compared to that in mothers with children having down syndrome . perhaps as the children with down syndrome can make stronger emotional ties with their mothers , while mentally retarded children can not , prevalence of depression was higher in the latter group .
khayatzadeh mahani stated that there was an association between mother 's quality of life and severity of her child 's disability , so mothers of children with lower abilities experience lower quality of life .
finally , this study showed that depression is seen more among the mothers with mentally retarded children , compared to other women . with regard to their very important role in the support of mentally retarded children ,
it is essential to screen such individuals as the high - risk ones and give them social support . with regard to the important role of women in the family , especially their role of motherhood , and
the existing risk for family 's and children 's health , conducting educational programs for school teachers who are in contact with these mothers is crucial to prevent , detect , and introduce them to related centers to be treated .
Output:
| background : nowadays , depression is one of the most prevalent mental diseases to which some individuals like mothers of mentally retarded children are more vulnerable due to their ( children s ) special condition .
therefore , the present study aimed to investigate the level of depression and its related factors in these mothers.materials and methods : this cross - sectional study was conducted on 120 qualified mothers with mentally retarded children who were from exceptional children girls schools in isfahan .
the subjects filled personal characteristics and beck depression inventory assessment , and their level of depression and its association with some baseline factors were analyzed through descriptive statistics in spss.results:results showed that 75% of the mothers experienced various levels of depression , of whom 25.8% suffered from minor depression , 24.2% from moderate depression , and 25% suffered from major depression .
the results obtained showed that there was a significant direct association between the intensity of depression and students age , mothers age , fathers age , the number of children , and the length of parents marriage and a reverse association between the intensity of depression and subjects , fathers , and mothers education ( p = 0.004 ) . no association was observed between mothers occupation and the intensity of depression .
meanwhile , there was a negative significant association between fathers occupation and mothers depression ( p = 0.02 ) .
about 33.3% of the mothers did not believe that their spouses and families psychological and mental support was adequate.conclusions:the present study showed that mothers of mentally retarded children are predisposed to depression . with regard to the important role of mothers in the family and , consequently , the risk of impaired health of the family members , especially these children 's health , prevention and diagnosis of depression and treatment of these mothers seem to be essential .
adequate support to these mothers plays a key role in reduction of the risk of their depression . |
PubmedSumm6555 | ***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: tsetse flies are vectors of african trypanosomes , the causative agents of sleeping sickness in humans and nagana in animals . following a long period of increasing prevalence
however , this debilitating disease still affects a wide range of people in sub - saharan africa and is invariably fatal if untreated .
nagana is estimated to cost african agriculture us $ 4.5 billion per year . until now ,
therefore , the search for novel strategies must continue and among them are alternative vector - based strategies .
these strategies require a clear and full understanding of the various steps and mechanisms involved in the transmission of the parasite . to be transmitted , trypanosomes must undergo cycles of development of varying complexity within the tsetse fly , transforming from bloodstream forms to procyclic nonmammalian infective forms in the fly midgut ( establishment ) . to complete their life cycle , trypanosoma brucei brucei and
the causative agents of human african trypanosomiasis , trypanosoma brucei rhodesiense , and trypanosoma brucei gambiense must migrate from the midgut to the salivary glands where they transform into infective metacyclic forms .
the fly 's ability to acquire the parasite , favor its maturation , and transmit it to a mammalian host is known as vector competence , which depends on complex interactions between glossina , the parasite , and the environment .
the factors involved in establishment are largely unknown and those involved in maturation are unclear .
nevertheless , among factors involved in vector competence appear to be the sex of the fly [ 6 , 7 ] , the trypanosome genotype , the tsetse intestinal lectin [ 9 , 10 ] , and the tsetse immune responses .
more recently , antioxidants have been shown to greatly increase midgut trypanosome infection rates in tsetse , suggesting that oxidative stress plays a role in the refractoriness of tsetse to trypanosome infection . moreover
, a no signal has been suggested to be required to promote the trypanosome migration to the salivary glands and its subsequent maturation into mammalian infective forms .
nevertheless , vectorial competence of a given glossina species could also be influenced by the nature of the parasite species .
moreover , differences in the establishment and maturation rates have even been observed for different genotypes belonging to a given parasite subspecies .
these observations demonstrate the complexity of the mechanisms governing parasite development in the tsetse fly . given that knowledge on the infection process that remains limited , further studies are required to characterize the overall glossina - parasite molecular interactions .
the identification of the proteins secreted by the insect procyclic parasite may contribute to the increasing of the understanding of the infection process and lead to the identification of potential targets for drug and/or vaccine design . in this respect
, we have investigated the excreted / secreted proteins ( esps ) produced by two procyclic trypanosoma brucei parasite subspecies ( t. brucei brucei and t. brucei gambiense ) and compared their respective secretomes .
stib 215 and biyamina [ 19 , 20 ] procyclic forms of trypanosoma brucei brucei and trypanosoma brucei gambiense , respectively , were grown at 25c , in cunningham 's medium supplemented with 20% fetal calf serum .
when the cultures displayed logarithmic growth , procyclic parasites were washed four times with phosphate buffer saline ( pbs ) and spun for 10 minutes for 2600 g at 25c .
the parasites were resuspended at a concentration of 2 10 cells / ml in a secretion buffer and incubated for 2 hours at 25c for esp production . during the incubation process
, the parasite cell viability was controlled every 15 minutes by flow cytofluorometry using the dna intercalant propidium iodide ( ip ) procedure .
briefly , 2 10 parasites were incubated with 1 g ip in 1 ml pbs as recommended by the manufacturer ( immunotech , marseille , france ) .
the cells were immediately analyzed with a facscan flow cytometer ( becton dickinson , ivry , france ) using an argon - ion laser .
the secretion of esps was stopped by centrifugation of the parasites , 2600 g for 10 minutes at 4c .
the supernatant was collected and filtered on 0.2-m filter and immediately mixed with protease inhibitors .
the esps were then concentrated by ultrafiltration on a pm 10 ( 10 kda cut - off ) membrane ( amicon ) for further protein electrophoretic separation ( sds - page ) . the protein concentration was determined by the bradford dye binding procedure ( bio - rad ) , and 300 g of esps were further separated using sds - page .
parasite pellets were resuspended at a concentration of 2 10 cells / ml of laemmli buffer .
the protein concentration was determined , and 100 g of proteins of the total proteomes were further separated using sds - page .
proteins from the different samples ( esps and total proteome ) were heated at 100c for 2 minutes and spun for 5 minutes for 14.000 g prior to separation using one - dimensional sds - page .
proteins were separated on 24 18 cm tricine / sds / urea - polyacrylamide gels ( 12% acrylamide ) . after migration ,
the gels were fixed , and the proteins were visualized using coomassie brilliant blue r-250 .
pictures of the gels were taken with an amersham biosciences personal densitometer ( bio - rad ) .
sixty four protein spots were excised manually from the one - dimensional gels of esps , washed , digested with trypsin , and extracted with formic acid .
protein digests were analyzed using either a triple - quadrupole mass spectrometer ( q - trap 4000 ; applied biosystems ) , coupled to a nanochromatography system ( dionex ) or an ion trap mass spectrometer ( esquire hct ; bruker ) , and interfaced with an hplc - chip system ( agilent ) .
ms / ms data were searched against ncbi and trypanosoma brucei databases using mascot software .
raw data were analyzed using data analysis software ( bruker ) to generate a peak list for searching a trypanosoma database extracted from the sanger institute .
the mascot ( v2.2 ) search engine was used with the following parameters : one missed cleavage allowed for trypsin , carboxymethylation of cyst as fixed modification , methionine oxidation as variable modification , and a 0.6-da tolerance range for mass accuracy in ms / ms .
at least one matching sequence of tags of high quality was needed for positive identification of proteins .
potential false - positive identifications have been addressed as described by elias et al . , ( 2005 ) , using identical search parameters against a database in which the sequences have been reversed .
we set a false discovery rate ( fdr ) of 1% . when the mascot peptide score was below ( and even above ) the mascot peptide score indicated for an fdr of 1% , a systematic manual validation was done with stringent parameters ( at least 6 y or b ions , at least 4 consecutive ions , and peptidic sequence formed of more than 7 amino acids ) .
the main objective of the study was a comprehensive characterization of the proteins secreted by two different strains of t. brucei in procyclic form , t. brucei gambiense / biyamina strain ( whose bloodstream form is pathogenic for humans ) and t. brucei brucei / stib 215 strains ( whose bloodstream form is pathogenic for animals ) .
a three - step investigation was conducted and consisted in the following : ( 1 ) one - dimensional electrophoresis profiling of the secreted proteins and comparison with the corresponding proteomes , ( 2 ) the identification of the secreted proteins by mass spectrometry and distribution into functional classes , and ( 3 ) a cross - comparative analysis between ( a ) the secretomes of the two strains ( procyclic forms ) and ( b ) the secretome of the procyclic forms and the proteome .
the profiles generated by the electrophoretic separation of the secretome proteins from the two procyclic parasite strains ( biyamina and stib 215 ) and their corresponding proteomes are shown in figure 1 .
a high number of bands were separated , corresponding to proteins with molecular weights ranging from 7.2 to 205.8 kda .
clear differences were noted between the electrophoretic profiles of the proteome of the two procyclic strains and their corresponding secretome profiles , in terms of both proteic band intensity and presence or absence of several protein bands .
furthermore , since over the entire 2-hour secretion process ( a ) the parasites ' viability remained constant and was greater than 98% and ( b ) the incubated trypanosomes presented normal morphology and motility , all these data indicate that the secretome resulted from an active export of proteins from living trypanosomes and not from cellular lysis .
the electrophoretic profiles of the proteome of the two procyclic strains show that they have many protein bands in common ( 3234 visible bands ) ; some differences in intensity were noted after coomassie staining
. visual observation of the 1d gels showed similarities as well as some quantitative and qualitative differences between the secretome profiles of the two parasite subspecies .
secreted proteins from procyclic strains were fractionated by 1d sds - page , and 64 spots were selected all along the 1d gel for ms / ms analysis .
this resulted in the identification of 427 secreted proteins from the stib 215 ( t. brucei brucei ) strain and 483 proteins from biyamina ( t. brucei gambiense ) .
supplementary table 1 ( in supplementary material available online at doi:10.1155/2010/212817 ) lists the proteins identified .
they were classified into 12 main functional categories ( figure 2 and supplementary table 1 ) . both of the procyclic strains ' secretomes , the proteins associated with unassigned functions , those associated with ( un)folding and degradation processes , and protein synthesis were quantitatively the largest categories , with a total of 60% of the secreted proteins ( figure 2 ) .
moreover , lipid and cofactor , transport , rna / dna metabolism , cell cycle and organization , nucleotide metabolism , and amino acid metabolism contribute approximately 26% of the secreted proteins , and finally carbohydrate metabolism accounts for about 9% of the secreted proteins .
globally , the importance ( expressed as the percentage of the proteins concerned ) of each functional class is similar for both procyclic strains , except for the redox and signaling classes that are under - represented in the t. brucei brucei strain ( stib 215 ) secretome as compared with the t. brucei gambiense strain ( biyamina ) ( figure 2 ) .
comparing the secretomes of two procyclic strains ( figure 3 ) showed 279 common secreted proteins ( 57.8% and 65.3% of the biyamina and the stib 215 esps , resp . ) , 204 ( 42.2% ) were specifically secreted by t. brucei gambiense ( biyamina ) , and 148 ( 34.7% ) were secreted by t. brucei brucei ( stib 215 ) .
the proteins specifically secreted by either stib 215 or biyamina were represented in all 12 functional categories previously identified . however , the ( un)folding and degradation protein class was particularly valuable because it grouped 14 different families of peptidases ; four of which were specifically secreted by the t. brucei gambiense procyclic strain ( biyamina ) and two others by t. brucei brucei ( stib 215 ) .
the other eight secreted peptidase families were common to both strains ( table 1 ) .
surprisingly , we also identified a serine protease inhibitor among the proteins secreted by both strains .
more than one - third of the proteins ( 39.2% ) specifically secreted by stib 215 procyclic strain corresponds to hypothetical proteins , although they account for only 27.8% in biyamina . of major interest
was the observation that some proteins , such as calreticulin and ige - dependent histamine - releasing factor which belong to the class of signaling proteins , were specifically secreted only by the biyamina strain ; this strain also secreted higher levels ( 2.9% ) of proteins belonging to the redox class .
finally , only 45% of the proteins secreted by the procyclic strains were common to the proteins from the procyclic total proteome ( figure 4 ) .
this data also corroborates that the secretome results from an active protein exportation from living cells .
the life cycle of trypanosoma is complex and requires the expression of specialized proteins for the development of the parasite in both invertebrate and vertebrate host environments , to escape host immune responses . for successful glossina infection
, the parasite has to adapt to its novel environment ; it must switch both from a homoiothermic to a poikilothermic host and from a mammal to an insect .
furthermore , it must develop new weapons or choose among its panel of weapons to fight a novel type of host defense . in vertebrate hosts ,
trypanosome bloodstream forms are protected by the variant surface glycoprotein ( vsg ) , which prevents their recognition by the host immune system . when the parasites are taken up by the insect in the blood meal
, they must confront the insect 's immune system , mainly composed of midgut proteases , physical barriers such as peritrophic matrix , reactive oxygen species [ 25 , 26 ] , and antimicrobial peptides .
a number of studies have revealed that the procyclins , surface glycoproteins expressed by trypanosome procyclic forms , may protect these forms against tsetse midgut proteases [ 28 , 29 ] . however , there are yet no examples of direct interactions between tsetse fly and trypanosome molecules .
the purpose of this study was to identify the whole excreted / secreted proteins in two trypanosome procyclic forms to better understand the interactions between the trypanosome and tsetse fly in terms of establishment in the midgut or vectorial competence and to search for new tools for vector control strategies .
we successfully used 1d electrophoresis and ms / ms to establish the first extensive protein map of the secretome of the procyclic form of the parasite using stringent mass spectrometry criteria to validate potential candidates ( false discovery rate ( fdr ) < 1% ) .
the substantial differences between the set of proteins secreted by both trypanosome strains and those of their respective total proteomes demonstrate that the proteins identified in the secretome are indeed secreted and are not an artifact resulting from possible cell lysis during the secretion step . sequencing 1d gel showed that a large number of proteins were specifically secreted by both biyamina ( t. brucei gambiense ) and stib 215 ( t. brucei brucei ) ( 42.4% and 34.6% , resp . ) .
the differences in the protein secretion profiles between the two parasite subspecies may reflect their genetic differences and could possibly be related to differences in glossina vector competence [ 14 , 15 , 3034 ] . to better understand the possible role of the secreted proteins ,
the groups of unfolding and degradation proteins , protein synthesis , and proteins with no assigned functions were the most numerous .
unknown or hypothetical proteins are a source of candidates that could be used to explore novel functions .
we did not expect to find so many different peptidase families among the unfolding and degradation classes of secreted proteins .
the group of proteases deserves the greatest attention because these enzymes cover a large panel of physiological and pathological functions .
consequently , representatives of this group are known to be virulence factors , to favor parasite invasion and its growth in the hostile host environment , to make it possible to escape the host immune defenses , and/or , finally , to produce nutrients by hydrolyzing host proteins .
some parasites such as plasmodium falciparum produce a diversified panel of secreted and surface - bound proteases . in a variety of animals , including humans as well as arthropods
, the blood clotting system plays an important role in the immobilization of invading parasites , and in preventing their dispersal from the site of initial invasion .
how the parasite proteases process to inactivate or cause the inappropriate expression of host immune defense systems is a major question .
in addition to their direct role as virulence factors , secreted proteases are involved in various housekeeping functions during parasitic infection . as shown in porphyromonas gingivalis , the proteolytic degradation of host proteins is able to produce nutritive elements for parasite growth .
virulence has correlated positively with the expression of secreted proteases in a variety of systems where virulence can be modified genetically or in response to environmental cues . as a result ,
strains of leishmania mexicana , engineered by targeted gene disruption of the genes encoding a pair of cysteine proteases , showed attenuated virulence .
the virulence of laboratory strains and clinical isolates of entamoeba histolytica correlates well with the level of activity of a secreted cysteine protease .
in addition , inhibitors of serine proteases have been shown to block the entry of merozoites of plasmodium into erythrocytes .
surprisingly , an inhibitor of serine proteases ( ecotin ) has been discovered in the secretion products of trypanosome strains .
the wide distribution of serine protease inhibitors , and their ability to regulate a variety of divergent proteinase - dependent physiological functions , shows that they are closely involved in a host of biological processes . in several systems ,
serine protease inhibitors from viruses have been implicated in pathogen escape from the host immune system . in brugia malayi ,
cysteine - protease inhibitors that can inhibit host proteases involved in antigen processing have been discovered . besides contributing to protect the parasite against the host 's defense mechanisms ,
in addition to their protein degrading activity , proteases perform highly specific processing tasks that can affect protein structure , function , life span , and localization . by limited and specific cleavage
, proteases can act as switches , turning protein activity on or off ; they can also modulate protein function in more complex ways , regulating vital processes .
consequently , proteases constitute both promising candidates for developing diagnostic tools and attractive drug targets to fight trypanosomes and subsequently to control sleeping sickness . proteins involved in signaling make up another group of proteins identified in the secretome of procyclic trypanosome , but even this is not a major class ; some proteins , such as calreticulin , could play physiopathological roles . autoantibodies against calreticulin
are found in the sera of human hosts in a number of parasitic diseases and it was suggested that the parasite - derived calreticulin could trigger an inappropriate immune response against self - antigens through molecular mimicry .
the class of proteins involved in protein synthesis is quantitatively ( 17% ) well represented in the secretome .
however , some proteins , such as elongation factor-1 , were suggested to be a virulence factor in leishmania .
we did not expect to find so many representatives of the carbohydrate metabolism protein class ( 9.79% in the t. brucei gambiense secretome and 8.27% in the t. brucei brucei secretome ) .
several papers have reported on the ability of the procyclic cell to adapt its metabolism to different environments . because tsetse hemolymph contains abundant supplies of amino acids , and because the tsetse fly itself uses proline as a major carbon source during flight , it has long been speculated that in situ , the procyclic form of trypanosomes , might use proline .
accordingly , proline is a key component in the culture media currently used to cultivate the parasite .
in contrast , another study has shown that , when grown in high glucose - concentrated media , the procyclic cells are susceptible to glycolytic inhibitors and to the downregulation of genes encoding glycolytic enzymes .
this confirms the flexibility of the trypanosome metabolism and its adaptability to diverse growth conditions .
cells grown under chemostat conditions were shown to regulate their glucose metabolism according to the availability of proline . since the buffer we used to stimulate protein secretion contained sugar , it was not surprising to find a high level of enzymes involved in carbohydrate metabolism .
besides , procyclic forms establish mainly in the vector 's midgut where sugar may be abundantly available immediately after a blood meal .
nevertheless , two major questions remain unresolved because glycolytic enzymes are expected to be intracellular enzymes .
( 1 ) why is there such a high level of carbohydrate metabolism enzymes secreted ?
( 2 ) what is the role of such enzymes when secreted in the fly 's midgut ? the redox - protein class of secreted proteins was poorly represented .
this finding was also unexpected because in the flies ' midgut , reactive oxygen species are generated during immune responses or because of the abundance of heme molecules freed from the digested blood meal .
in addition , some of these proteins may play roles other than the detoxification of reactive oxygen . therefore
, a superoxide dismutase ( sod ) has been shown to be secreted by t. cruzi ; it was suggested that this enzyme was involved in both the parasite defense mechanism and the establishment of the parasite in the host [ 52 , 53 ] . in another context
, sod was considered to participate in the immune escape in filarial infections [ 54 , 55 ] . finally , in the procyclic parasite secretome
, we have identified 13 ( gapdh , clathrin heavy chain , rab protein , ubiquitin , 14 - 3 - 3 proteins , cyclophilin , enolase , hsp70 , actin , cofilin , tubulin and , and histone ) out of the 22 proteins commonly associated with the exosome secretion pathway in various organisms .
moreover , we have also identified translationally controlled tumor protein ( tctp ) in this secretome .
this protein was shown to be present in exosomes [ 57 , 58 ] .
these results suggest that the secretome proteins may be secreted via an exosome pathway that has never been described until now in trypanosomes .
this also suggests that exosome - directed transmission - blocking vaccines could be developed and are capable of suppressing the capacity of the parasite to infect the vector and consequently preventing the spread of the parasite in human populations .
to conclude , the trypanosoma parasite is a multistage organism that evolves in tsetse flies and vertebrates .
designing drugs that persistently interrupt the life cycle of this parasite requires a comprehensive understanding of its biology and the mechanism involving the vector - parasite interactions .
the primary goal of our proteomic investigation was to identify secretome proteins of procyclic parasites to improve the knowledge of these interactions .
the secretome encompasses a spectrum of proteins that may be required for every facet of the parasite 's lifestyle , from the modification of the physiological environment to the immune escape .
this may open leads to initiate novel strategies for controlling the parasites and sleeping sickness .
Output:
| trypanosoma secretome was shown to be involved in parasite virulence and is suspected of interfering in parasite life - cycle steps such as establishment in the glossina midgut , metacyclogenesis .
therefore , we attempted to identify the proteins secreted by procyclic strains of t. brucei gambiense and t. brucei brucei , responsible for human and animal trypanosomiasis , respectively .
using mass spectrometry ,
427 and 483 nonredundant proteins were characterized in t. brucei brucei and t. brucei gambiense secretomes , respectively ; 35% and 42% of the corresponding secretome proteins were specifically secreted by t. brucei brucei and t. brucei gambiense , respectively , while 279 proteins were common to both subspecies .
the proteins were assigned to 12 functional classes .
special attention was paid to the most abundant proteases ( 14 families ) because of their potential implication in the infection process and nutrient supply .
the presence of proteins usually secreted via an exosome pathway suggests that this type of process is involved in trypanosome esp secretion .
the overall results provide leads for further research to develop novel tools for blocking trypanosome transmission . |
PubmedSumm6556 | ***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 previous issue of critical care , van herpe and colleagues describe a new method of blood glucose reporting for hospitalized patients , the glycemic penalty index ( gpi ) . a stepped scale weights the clinical significance of differences of blood glucose ( bg ) from target .
the gpi scale is appropriately accordioned on the hypoglycemic range and expanded on the hyperglycemic range .
the authors recommend that use of the index should be combined with counting of episodes of severe hypoglycemia .
the index , capturing both overall hyperglycemia and hypoglycemia , could permit analysis of the ability of an algorithm to control between - patient glycemic variability . in the evaluation of glycemic control , the measures that are simplest to ascertain are the average and standard deviation , using the bg as the unit of observation .
in the leuven , belgium surgical intensive care unit , the standard deviations in intensively and conventionally treated groups was 19 and 33 mg / dl , respectively .
it could have been asked whether the greater bg variability in the conventionally treated group reflected the contribution of a hyperglycemic subgroup . until a second report was issued referring to control at the patient level , within the conventionally treated group even the relationship between hyperglycemia and mortality rate was unclear . in order to evaluate patient outcomes , there is no substitute for reporting on the patient as the unit of observation .
a key question is whether patient outcomes relate to overall hyperglycemia during a critical timeframe or to specific episodes of severe hyperglycemia .
the answer , predicated upon the mechanism of harm , could depend upon what outcome is being studied .
single episodes of severe hyperglycemia , such as the in - hospital development of diabetic ketoacidosis or hyperglycemia - associated dehydration , may result in specific consequences , such as dialysis fistula thrombosis , readmission to a critical care unit , or treatment - related pulmonary edema .
the association of single episodes with outcomes was recognized by stagnaro - green and colleagues .
furnary and colleagues , capitalizing upon a critical window of time in the postoperative interval following heart surgery , have reported on outcomes in relation to the " 3-day bg , " each value representing a patient 's 3-day average of postoperative bg measurements .
recent literature supports the importance of overall prevention of hyperglycemia , at least during critical windows of time , with respect to survival and morbidities such as sepsis , renal failure , duration of ventilator dependency , or transfusion requirement .
unfortunately , we have no simple measure comparable to the a1c by which the short - term inpatient overall glycemic control of an individual may be described . although hypoglycemia might simply reflect severity of comorbidities , the correlation between hypoglycemia and mortality of hospitalized patients is well known .
evidence from a mixed intensive care unit suggests that hypoglycemia is an independent predictor of mortality . among groups of patients having myocardial infarction or congestive heart failure
, observational patient - level data suggest that when mortality is considered as a function of overall bg concentration , there may be a j - shaped curve , such that patients having the lowest and the highest averages experience outcomes worse than those having intermediate range bg control .
is there a plausible mechanism by which modest overall reduction of average bg might cause harm , and if so , what specific harm is caused ?
alternatively , is harm a consequence of isolated episodes of severe hypoglycemia , to which the population having lower average bg is more vulnerable ? in the literature concerning strict glycemic control , serious or fatal consequences of hypoglycemia occasionally are reported . however , even when severe hypoglycemia is reported , sublethal permanent neurological injury seldom is described .
if a patient - level metric relied only upon bg averaging methods , isolated episodes of severe hypoglycemia could be overlooked that had resulted in altered function with respect to the activities of daily living or reduction of intellectual capacity .
application of the gpi index is cumbersome , such that other centers may have difficulty in adopting the method ; therefore , the measure may remain unfamiliar .
perhaps overall hyperglycemia and discrete episodes of hypoglycemia ought not to be captured by the same metric .
an extra mental step is needed to quantify the contribution of hypoglycemia and hyperglycemia as a fraction of the total value of the index .
multiple small episodes of hypoglycemia , none having clinical impact , might be weighted equally to one severe life - changing episode .
analysis of episodes of severe hypoglycemia should complement the use of the gpi , as the authors acknowledge . with that caveat , can a single measure sum up patient risk for a variety of outcomes that might be related to glycemic control ?
we await evidence that the gpi will improve upon our ability to define glycemic targets and predict clinical outcomes .
Output:
| the article by van herpe and colleagues in the previous issue of critical care describes the glycemic penalty index ( gpi ) , which weights both hyperglycemic and hypoglycemic blood glucose measurements commensurate to their clinically significant difference from target .
although certain adverse consequences result from isolated severe hyperglycemic episodes , several specific outcomes depend upon overall hyperglycemia .
in contrast , although mortality has been related epidemiologically to overall low blood glucose , specific negative outcomes may depend upon isolated episodes . capturing both hypoglycemia and hyperglycemia in a single index
will be shown to be useful if the gpi enables us to better define insulin strategies , outcomes , and targets . |
PubmedSumm6557 | ***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: metformin ( n , n-dimethylbiguanide ) is a widely used drug for the treatment of type 2 diabetes mellitus , condition associated with insulin sensitivity and obesity .
additionally , it has been shown that metformin may inhibit growth of tumor cells and thus potentially may find application in therapy of various types of cancer [ 16 ] .
metformin was also classified for conceptual group of drugs , known as calorie restriction mimetics ( crm ) .
have shown that calorie restriction model involving metformin supplementation is a very effective way of increasing the lifespan by reducing morbidity and mortality both of healthy mice and of mice with tumor .
the progressive aging of the human population together with increasing obesity are the main reasons of metabolic diseases .
the world health organization ( who ) reported that over 500 million people suffer from overweight and/or obesity ( data from 2013 ) . this serious medical condition becomes a great challenge for modern pharmacotherapy .
metformin is considered a part of the solution to this problem due to its multidirectional action on adipose tissue metabolism [ 9 , 10 ] .
metformin has an ability to decrease adiposity and obesity related conditions what was proved either in human or animal model [ 1114 ] .
additionally , according to a randomized study performed by srinivasan et al . and yanovski et al .
children and adolescents may be much more responsive to metformin - induced weight reduction as compared to adults .
these results might suggest that the metformin has an effect not only on morphology and distribution of fat tissue but also on proliferation potential of adipocytes precursors .
progenitor cells in the uncultured stroma - vascular fraction ( svf ) derived from adipose tissue usually amount to up to 3% of the whole cells .
this unique population is defined as adipose - derived multipotent stromal cells , ascs [ 15 , 16 ] .
although ascs are of mesoderm origin , these stem cells possess a unique ability to differentiate into ectoderm and endoderm lineages as well as mesoderm cells .
ascs are increasingly being not only used as a research tool , but also applied in the human and veterinary medicine cell therapy .
the reason for this is that they can be easily obtained in large quantities with little donor site morbidity or patient discomfort .
ascs become a source of cells characterized by high proliferative potential , stable growth , and kinetics and thus are considered a promising candidate in regenerative medicine .
asc - based therapies have been shown to be safe and efficacious in the preclinical and clinical studies of various injuries and diseases [ 18 , 19 ] .
given the fact that metformin exerts an unquestionable influence on adipose tissue , which becomes a source of a unique stem cell population , it was reasonable to investigate the effects of this compound on the proliferation potential , morphology , and ultrastructure of the ascs .
markers that can be associated with cells proliferation are ki-67 and osteopontin ( opn ) . additionally ,
expression of another marker , for example , cd105/endoglin , should be taken into consideration , because it defines mscs provenance and is associated with preadipocytes proliferation and differentiation potential [ 20 , 21 ] .
ki-67 is a ubiquitous human nuclear protein expressed in g1 , s , and g2 phases of the cell cycle [ 22 , 23 ] and therefore is used as indicator of growth fraction of particular cells population .
ki-67 was also used to quantify preadipocyte replication when assessing cellular turnover within adipose tissue of mice and humans . in turn
, osteopontin is a multifunctional protein mainly associated with osseous tissue metabolism and bone remodeling .
it is expressed in proliferating fibroblast and in osteogenic and periodontal ligament cell populations [ 26 , 27 ] . moreover ,
opn upregulation is also connected with variety of acute and chronic inflammatory conditions , such as wound healing , fibrosis , autoimmune disease , and atherosclerosis .
the osteopontin is also regarded as a mediator linking obesity to the development of insulin resistance by promoting inflammation and the accumulation of macrophages in adipose tissue .
bearing in mind all mentioned facts , determination of expressions of ki-67 and osteopontin in adipose tissue of mice treated with metformin seems to be crucial regarding its influence on ascs proliferation activity . to the best of our knowledge
therefore , to obtain complex information concerning effect of metformin of ascs and adipose tissue , we decided to approach this subject bidirectionally , performing in vitro and in vivo studies .
we evaluated not only proliferative activity of ascs exposed to metformin , but also their morphology and ultrastructure .
metformin accumulates in tissues of diabetic mice in concentrations several times higher than those in blood [ 30 , 31 ] , and therefore three concentrations of metformin ( 1 mm , 5 mm , and 10 mm ) were applied in this study .
the aim of in vivo study was to evaluate the effect of metformin on histological structure of adipose tissue and to determine expression of proliferation markers .
we believed that the data presented in this study will provide meaningful information of clinical significance , especially due to the fact that substantial part of our research was dedicated to cells morphology investigation , important in diagnosis of pathology .
all reagents used in this experiment were purchased from sigma - aldrich ( poland ) , unless indicated otherwise .
all experimental procedures were approved by the ii local ethics committee of environmental and life science university ( dec .
the cells were isolated from subcutaneous adipose tissue of six c57bl/6 mice using protocol established previously [ 32 , 33 ] .
tissue fragments were minced and digested using type i collagenase for 40 minutes at 37c . next , the tissue homogenates were centrifuged for 10 min at 1200 g .
the supernatants were aspirated and the pellets of the stromal - vascular adipose fraction , containing mscs precursors , were washed with hank 's balanced salt solution and centrifuged three times ( 5 min at 600 g ) .
pellets were then suspended in dulbecco 's modified eagle 's medium ( dmem ) with nutrient f-12 ham and transferred to culture flasks .
cultures were maintained at 37c in a humidified atmosphere of 5% co2 and 95% air .
culture media were supplemented with 10% fbs and 1% antibiotics ( penicillin and streptomycin ) .
, the cells were passaged three times , using trypsin solution ( tryple ; life technologies ) according to manufacturers ' instruction .
phenotypic characterization of cells was performed using ascs cultures derived from animals assigned for in vitro tests .
analyzed cells were adjusted in terms of subculture ( all after second passage ) . for staining ,
for each staining , cultures were run in triplicate . to determine the phenotype of cells , the expression of following markers
the antibodies used for the analysis were purchased from sigma ( rabbit anti - mouse integrin - b-1 ( cd29 ) , dilution 1 : 100 ; rabbit anti - mouse nt5e ( cd73 ) , dilution 1 : 200 ; rabbit anti - mouse endoglin ( cd105 ) , dilution 1 : 200 ; rabbit anti - mouse cd45 , dilution 1 : 100 ) , except for anti - cd44 which was obtained from r&d systems ( rabbit anti - mouse cd44 , dilution 1 : 100 ) .
secondary antibody conjugated with atto-488 fluorescence label was purchased from sigma ( goat anti - mouse igg atto-488 , dilution 1 : 400 ) .
incubation with primary antibodies was carried out overnight , while the reaction with secondary antibodies was performed at 37c for 1 hour in the dark . in order to determine background fluorescence and exclude nonspecific staining
negative controls were incubated with secondary antibody for 1 hour at 37c in the dark .
the samples were imaged using an inverted fluorescence microscope ( axioobservera1 , carl zeiss , jena , germany ) .
images were captured with cannon powershot camera and merged using axiovision 4.8 software ( carl zeiss , jena , germany ) .
osteogenic and adipogenic differentiation of ascs were induced using commercial kits ( stempro , life technologies ) .
osteogenesis was induced during 21-day period , while stimulation toward adipocytes lasted for 14 days . to evaluate results of osteogenic and adipogenic differentiation ,
two specific staining methods were used , that is , alizarin red for determination of calcium deposits and detection of neutral lipid deposits performed using hcs lipidtox green neutral lipid stain , and according to the manufacturers ' instruction preparations were analyzed using axio observer a1 inverted and epifluorescent microscope ( axio observer a1 , carl zeiss , jena , germany ) , while the documentation was made using cannon powershot camera . for assays ,
metformin hydrochloride ( metformax 850 , teva pharmaceuticals , poland ) was crushed in a mortar and dissolved in the culture medium at the following concentrations : 1 mm , 5 mm , and 10 mm .
nontreated cells served as a control for comparison with the test culture . in order to performe further analysis ( including morphology , ultrastructure , and gene expression )
proper number of culture plates was performed to investigate cells in the chosen time - points .
the first dosage of metformin was added to the culture after 24 hours . during the cell treatment medium
the viability of the cells was evaluated after 24 , 48 , and 72 hours using a resazurin - resorufin system ( alamar blue ) . to perform the test ,
the supernatants were collected and transferred to a 96-well microplate reader ( spectrostar nano , bmg labtech ) .
the absorbance of the supernatants was measured spectrophotometrically at a wavelength of 600 nm for resazurin and 690 nm as a reference wavelength .
proliferation activity was described using a value , expressing difference of absorbance of supernatants at 600 and 690 nm and including absorbance of blank samples .
asc morphology was evaluated under epifluorescent microscope ( zeiss , axio observer a1 ) and scanning electron microscope ( sem , zeiss evo ls 15 ) .
the analysis of morphology was performed after 24 h and 72 h of culture in 24-well plates .
the preparation of ascs for fluorescent microscopy was performed according to established procedure [ 34 , 35 ] and included the following stages : ( i ) washing three times using hbss , 1 min each ; ( ii ) fixation of cells in 4% ice cold paraformaldehyde , performed overnight at 4c ; ( iii ) washing of cells ( as described above ) ; ( iv ) 15 min of cell permeabilization with 0.1% triton x-100 at room temperature ; ( v ) washing of cells ( as described above ) ; ( vi ) staining with atto-488-labeled phalloidin ( 1 : 800 ) for 30 min performed in the dark at room temperature ; ( vii ) counterstaining using diamidino-2-phenylindole ( dapi ; 1 : 1000 ) for 5 min at room temperature . for the detection of apoptotic cells ,
simultaneously to dapi staining , immunofluorescence staining of caspase-3 was performed using polyclonal rabbit anti - mouse caspase-3 antibody ( dilution 1 : 100 ) .
additionally , for detection of dead and apoptotic cells analysis using cellstain double staining kit with propidium iodide was conducted .
cells were fixed in 2.5% glutaraldehyde in dmem , ( ii ) rinsed with hbss , ( iii ) dehydrated in a graded ethanol series ( from 50% to 100% , increasing every 10% ) , ( iv ) air - dried for 30 min at room temperature , and ( v ) coated with gold using 300-second program ( edwards , scancoat six ) .
prepared samples were captured using a se1 detector at 10 kv filament tension ( sem , zeiss evo ls 15 ) under 500x and 5000x magnification . for tem analysis ,
briefly , cells were fixed overnight at 4c in 2.5% glutaraldehyde in dmem . after fixation
, cells were centrifuged at 2000 g for 10 min and rinsed with pbs ( 0.1 m , ph = 7.0 ) for 30 min at room temperature .
cells were washed once again using 0.1 m pbs and centrifuged . following this procedure ,
the cells were dehydrated in a graded acetone series ( 30100% ) and embedded using agar low viscosity resin kit ( agar scientific ltd .
ultrathin sections ( 80 nm ) of the specimens were collected on copper grids .
cells were contrasted with uranyl acetate ( 30 min incubation ) and lead citrate ( 15 min incubation ) .
cells were imaged with tem detector , at 10 kv filament tension . after 24 and 72 hours of culture , cells were rinsed twice using hbss and then homogenized using 0.8 ml of tri reagent .
total rna was isolated using a single - step method described by chomczynski and sacchi .
the quantity and quality of total rna were determined using a nanospectrophotometer ( vpa biowave ii ) .
traces of genomic dna ( gdna ) were digested with dnase i rnase - free kit ( thermo scientific ) .
complementary dna ( cdna ) was obtained in the reaction with moloney murine leukemia virus reverse transcriptase ( m - mlv rt ) and oligo(dt)15 primers ( verte kit oligo(dt)15 , novazym ) .
both rna purification and cdna synthesis were performed in accordance with manufacturers ' instructions using the t100 thermal cycler ( bio - rad ) .
detection of osteopontin was performed using following primers : ( i ) forward 5-agaccatgcagagagcgag-3 and ( ii ) reverse 5-gccctttccgttgttgtcct-3 ( ncbi accession number : nm_001204203.1 ) .
beta-2 microglobulin ( 2 m ) was used as housekeeping gene ; sequences of primers were as follows : ( i ) forward 5-catacgcctgcagagttaagca-3 and ( ii ) reverse 5-gatcacatgtctcgatcccagtag-3 ( ncbi accession number : nm_009735.3 ) .
quantitative rt - pcr was carried out in a total volume of 20 l using sensifast sybr and fluorescein kit ( bioline ) .
the following cycling conditions were applied : 95c for 2 min , followed by 45 cycles at 95c for 5 sec , annealing 58c for 10 sec , and 72c step for 5 sec with a single fluorescence measurement .
analysis of the dissociation curve of amplicons was performed to determine the specificity of the pcr products .
melting curve was determined with a gradient program of the range from 65 to 95c at a heating rate of 0.2c / s and continuous measurement of the fluorescence .
the values of the threshold cycle ( ct ) obtained in each experiment were used to calculate fold change in relation to the expression of housekeeping gene .
real - time pcr was performed using cfx connect real - time pcr detection system ( biorad ) .
the concentration of opn was measured by enzyme - linked immunosorbent assay ( elisa ) using a commercially available elisa kit ( duoset elisa development kit ; r&d systems ) .
eighteen c57bl/6 mice ( females , 4-week - old ) were housed three per cage in an ultraclean facility on ventilated racks and were provided food and water ad libitum during the 5-week experiment .
the animals were purchased from animal laboratory house , wroclaw medical school , and housed in the animal experimental laboratory ( wroclaw medical school , poland ) .
mice received a standard diet with 4,2% fat ( morawski , labofeed h , poland ) and were maintained on a 12-hour light - dark cycle at 22 0.2c .
the animals used in the study were divided into two groups : ( i ) control ( n = 9 ) receiving drinking water only and ( ii ) the group receiving metformin in drinking water at a concentration equal to 2,8 mg / day ( metformax 850 ; teva pharmaceuticals , poland ) ( n = 9 ) .
after the experiment , mice were fasted for 24 h. body weight measurement was carried out using electronic weight ( radwag ps / c1 series , poland ) .
biochemical analysis of blood samples , such as glucose and lipids measurements , was performed with erba xl 300 platform ( erba diagnostics
after euthanasia of animals , adipose tissue was collected from abdominal subcutaneous layer of all animals .
subcutaneous adipose tissue ( 0.5 g ) was fixed in a cold 4% paraformaldehyde ( sigma - aldrich ) .
next , samples were transferred to 0.1 m phosphate buffer and incubated for 24 hours .
the samples were applied on a specimen holder using tissue freezing medium and transferred to a freezer ( 20c ) .
the samples were cut into sections of 0.5 m thickness and subsequently stained using mayer hematoxylin ( sigma - aldrich ) .
sections were prepared in six replicates and deposited on superfrost ultra plus adhesion slides ( thermo scientific ) .
morphometric analysis of adipose tissue was performed with axio imager light microscope ( zeiss ) using 10 fields of view for each individual ( each slide ) based on our previous experience .
the image j software ( http://rsbweb.nih.gov/ij/ ) was used to measure size and area of adipocytes .
adipocytes that were damaged or overly distorted owing to processing were not included in the measurements . moreover ,
number of crown - like structures ( cls ) was determined from six random microscopic fields magnified 100x . for immunohistochemistry , 4 m frozen sections were placed on superfrost ultra plus adhesion slides ( thermo scientific ) .
the samples were stored at 20c and before preparations were rehydrated . for each staining , two specimens were prepared .
antibodies used in the experiment were raised against mouse opn , ki67 ( 1 : 200 ) ( both purchased from abcam ) , and caspase-3 markers ( 1 : 100 ) ( sigma ) as well as cd44 ( 1 : 500 ) and cd105 ( 1 : 100 ) antigens ( both from abcam ) .
obtained samples were incubated with specific antibodies over night at 4c . after rinsing with hbss
, sections were incubated for 1 hour with goat anti - rabbit igg antibody conjugated with atto-488 ( dilution 1 : 200 ) , avoiding direct light .
nuclei were counterstained using 4,6-diamidino-2-phenylindole ( dapi , dilution 1 : 1000 ) .
incubation of specimens with dapi ( 5 min ) was followed by hbss washing .
specimens were visualized using epifluorescence microscopy ( axio observer a1 , zeiss ) with a 100-fold magnification .
nonspecific staining of the samples was reduced by incubation with a blocking buffer for 30 minutes .
the incubation buffer contained goat serum ( 1 : 100 ) , bovine albumin ( 1 : 10 ) , and triton - x ( 0.3% ) . the opn concentration was measured using elisa kit ( duoset elisa development kit ; r&d systems ) .
the test was performed similarly as it was described in paragraph 1.7 , with the difference that serum samples required 100-fold dilution .
the normality of the population data was determined using shapiro - wilk test , while equality of variances was assessed by levene 's test .
differences between groups were determined using one- or two - way analysis of variance ( anova ) .
, statistica for windows , tulsa , ok , usa ) . differences with a probability of p < 0.05 were considered significant .
to confirm multipotent and mesenchymal character of isolated stromal cells , immunohistochemical staining and multipotency assay were performed .
analyses were conducted with regard to the recommendations of international society of cellular therapy [ 39 , 40 ] .
immunohistochemical analysis revealed that ascs showed a negative reaction with an antibody against the hematopoietic marker , cd45 ( figure 1 ) .
in contrast , the cells were positive for mesenchymal markers characteristic for multipotent stromal cells , for example , cd29 , cd44 , cd73 , and cd105 ( figure 1 ) . the multipotency of mice adipose - derived mesenchymal stem cells was confirmed by the positive results of osteo- and adipogenic differentiation ( figure 2 ) .
ascs cultured under osteogenic conditions formed extracellular matrix rich in mineral calcium deposits visualized by alizarin red staining ( figure 2(b ) ) . in adipogenic cultures after 14 days of stimulation the formation of lipid droplets was observed ( figure 2(c ) ) .
the proliferation activity of ascs in vitro , after exposition to the investigated concentrations of metformin , was evaluated after 24 , 48 , and 72 hours of culture ( figure 3 ) .
determination of cell activity in control culture demonstrated that during the first 48 h the growth of cells was exponential . between 48 and 72 hours of the culture , the growth rate declined , implying stationary phase of growth .
proliferation of ascs cultures significantly decreased after 48 h of exposition to the metformin .
the inhibition of ascs cell growth by metformin occurred in a dose - dependent manner . despite the fact that proliferation rate of ascs in cultures with metformin at concentration equal to 1 mm was significantly lower in relation to the control culture , the growth curve had exponential character .
exposure of ascs to the 5 mm and 10 mm metformin inhibited growth of cells ; however after 72 h the proliferation activity of cultures was restored but at the level significantly lower than in control cultures .
the morphological and ultrastructural changes of ascs were examined after 24 and 72 h of the experiment in cultures treated with 1 mm , 5 mm , and 10 mm metformin and compared to the control culture ( figures 4 , 6 , and 7 ) .
the characteristic feature of the obtained ascs cultures was occurrence of both small and large multipolar fibroblast - like cells ( indicated in figure 4 with white arrows ) .
analysis performed using epifluorescence microscope showed that exposure to metformin influenced cells morphology and growth pattern of cultures . in cultures treated with metformin ,
the formation of apoptotic bodies was also more evident and their number was positively correlated with the metformin dose ; the increase of apoptotic bodies , visualized with dapi , was the most significant in culture exposed to 10 mm metformin .
the ascs maintained in control cultures were characterized by the high proliferative activity of cells also expressed by the formation of well - developed monolayer .
cultures treated with metformin were characterized by the irregular pattern of growth , both dispersed , as in cultures exposed to 1 mm metformin , and aggregated , as in culture treated with 5 mm of metformin .
the degeneration of ascs culture was observed after 72 h as a result of exposure to 10 mm of metformin .
moreover , the analysis of characteristic signs of cell death , performed after 72 h of culture , showed that the percentage of dead and apoptotic cells was increasing with the metformin dose ( figure 4 : propidium iodide and caspase-3 staining ) . additionally , dead cells visualized with propidium iodide were counted .
the result of comparative analysis regarding the number of dead cells in experimental versus control culture was shown in figure 5 .
analysis of cellular junctions formation showed that addition of metformin caused decline of cytoplasmic projection . in the control culture , intercellular connections during the culture period became narrowed , indicating on tight cell - cell interaction in formed monolayer .
interactions between plasma membranes of cells in experimental cultures were noticeable only after 24 hours ; however connections between cells were not maintained in cultures treated with the drug for 72 hours .
week development of cellular projections was evident especially when 5 mm and 10 mm metformin were used ( figure 6 ) .
the influence of metformin on cells ' ultrastructure was expressed mainly by the changes of nuclei shape , size of endosomes and mitochondria , and the number of plasma membrane - derived particles ( microvesicles , mvs ) shedding ( figure 7 ) .
the ultrastructure of ascs treated with the lowest concentration of metformin was comparable to the ultrastructure of control cells .
cells both derived from control culture and treated with 1 mm of metformin were characterized by the centrally located nuclei surrounded mainly by small , early endosomes and formation of mvs .
cells treated with 5 mm and 10 mm of metformin were characterized by peripherally located nuclei and enlarged , late endosomes . in these cultures ,
mvs shedding was incidental . additionally , the ascs treatment with metformin at concentrations of 5 and 10 mm caused ultrastructural abnormalities in mitochondria ( enlargement of mitochondria ) .
similarly , after 72 h of culture control cells from control culture and from culture stimulated with 1 mm of metformin shared some common ultrastructural features , like peripheral displacement of nuclei and increased number of mvs .
the distinctive feature of cells derived from culture treated with 5 mm was increase of nuclei size , occupying substantial part of cell body , and alteration of its shape .
degenerative changes of ascs , treated with the highest dose of the drug , involved invagination and disintegration of cellular membrane , excessive accumulation of endocytic vesicles , and disintegration of cell nuclei ( figure 7 ) .
analysis of opn gene expression was investigated in cells derived from experimental and control cultures , after 24 h and 72 h of propagation ( figure 8) .
quantitative analysis of transcripts revealed that the expression of opn in ascs after 24 h treated with 1 mm and 5 mm of metformin decreased in comparison to the opn mrna expression in control culture ; however observed differences were not statistically significant .
the propagation of ascs with 10 mm metformin for 24 h caused significant inhibition of opn mrna expression .
expression of opn mrna level was elevated after 72 h , when treated with 1 mm ; however the increase was not statistically significant .
inhibition of opn mrna expression at significant level was noted in cultures maintained for 72 h with 5 mm and 10 mm of metformin .
the level of secreted metformin in experimental cultures decreased in time and in dose - dependent manner , while in control cultures highest concentration of opn protein was noted after 72 h of culture .
the concentration of opn decreased significantly in all experimental cultures after 48 h of propagation ( figure 9 ) . in our experiment ,
additionally , mice treated with metformin had lowered glucose and triglyceride levels , whereas cholesterol level increased ( table 1 ) . all differences observed were statistically significant ( p < 0.001 ) .
evaluation of the adipocytes morphology and results of morphometric analyses are shown in figure 10 .
histological examination of abdominal subcutaneous fat tissue collected from mice treated with metformin and from control animals revealed significant morphological changes regarding size of cells and their organization in the tissue .
adipocytes forming adipose tissue of control mice were larger ( 16.95 1.21 m ) than adipocytes of experimental mice ( 13.97 2.01 m ) .
the areas of adipocytes derived from experimental animals were also smaller than in control group .
additionally , population of adipocytes in tissue of control mice was more homogenous both in size ( within a range of 15.4618.67 m ) and in shape ( mainly polygonal ) , while adipocytes forming adipose tissue of experimental mouse had divergent size ( within a range of 11.0218.21 m ) and morphology .
the formation of crown - like structures in adipose tissue of experimental animals was more evident ; however comparative analysis of cls number showed that difference between groups is not relevant .
the immunohistochemical analysis of subcutaneous fat tissue collected from animals treated with metformin and control animals demonstrated positive reaction for the following markers : cd105 , cd44 , opn , ki67 , and caspase-3 ( casp-3 ) .
however , substantial differences in the quality and intensity of reaction between investigated groups were observed ; results were presented in figure 11 .
fat biopsies of control animals exhibited stronger reaction for cd44 and cd105(figures 11(b ) and 11(f ) , resp . ) in comparison to animals treated with metformin ( figures 11(d ) and 11(h ) ) .
the expression of opn in the fat tissue of animals treated with metformin was weaker ( figure 11(l ) ) when compared to the control animals ( figure 11(j ) ) .
the reaction with ki67 antigen was also more abundant in the fat biopsies of control animals ( figure 11(n ) ) than in tissues obtained from experimental animals ( figure 11(p ) ) . in turn , the expression of caspase-3 staining in the fat tissue of animals treated with metformin was higher ( figure 11(t ) ) , when compared to the tissue derived from control animals ( figure 11(r ) ) .
evaluation of opn serum concentration measured with elisa showed that mice treated with metformin exhibit significantly lower opn level than mouse in control group .
in the present study we investigated the effects of metformin on adipose - derived mesenchymal multipotent stromal cells ( ascs ) and adipocytes , especially in relation to their proliferative potential . we have also focused on the evaluation of the influence of metformin on the morphology of both cells population of adipose tissue , and thus the results presented here include in vitro and in vivo studies .
metformin is known mainly for its antidiabetic properties , but it may also produce physiological effects comparable to calorie restriction . for instant , it may decrease fat mass and reduce size of adipocytes , as it was shown in depots of subcutaneous tissue of patients with diabetes [ 41 , 42 ] .
additionally , it has been shown in in vitro studies that metformin may increase glucose uptake of adipocytes and embryonic tissues [ 43 , 44 ] . because glucose is a crucial nutrient for proliferating cells
, it was of our interest whether metformin has an effect on proliferation of adipocytes precursors ( ascs ) and adipocytes .
the application of ascs for regenerative medicine becomes more and more frequently investigated in both basic biological research , fundamental in context of establishing of ascs cytophysiology , and preclinical studies .
fibroblasts and cancer cells by activation of ampk and inhibition of multiple molecular signaling pathways , which are important in protein synthesis control [ 4749 ] .
the field of our interest was to evaluate the influence of metformin on the expression of osteopontin which is a multifunctional protein involved in various inflammatory processes , cell proliferation and migration , and tissue remodeling . when comparing proliferation activity of ascs in vitro in experimental and control cultures with the supernatant concentration of opn measured with elisa , we have found similarity in the pattern of curves ' course . in the first 24 hours of cultures
the proliferation activity of cells and opn concentration in all investigated groups were at the same level . both proliferation and opn concentration significantly decreased after 48 h in cultures exposed to the metformin .
inhibition of proliferation activity of cells was also correlated with opn decrease at mrna level ; the transcript level depends on dose used in culture , and the lowest expression of opn mrna was noted in cultures treated with 10 mm of metformin .
inhibited expression of opn gene along with other osteogenic markers after treatment with metformin was noted previously in primary osteoblasts and mouse osteoblastic cell line ( mc3t3-e1 ) . in this paper , the authors revealed that osteogenic differentiation was downregulated significantly by 2 mm of metformin and also due to glucose restriction .
this occurrence was associated by the authors with ampk activity , as its phosphorylation was induced by metformin .
additionally it was proven that sustained phosphorylation of ampk was well correlated with the inhibition of matrix mineralization .
the authors of this paper revealed that phosphorylation of ampka in osteoblasts caused by metformin strongly depends on its dose , which is very important .
the metformin action in time- and dose - dependent manner was also noticed by the other researcher groups in various cell cultures .
the concentrations of metformin which was used in this study were also tested in cultures of human oral squamous cell carcinoma and significantly reduced the colony formation of those cells in vitro .
abu - zaiton has shown that metformin at concentration of 100 g / ml inhibits fibroblast proliferation , at both the normoxia and hypoxia conditions .
showed also that metformin may negatively influence adipogenic differentiation of progenitor cells isolated from bone marrow .
interestingly , the effects of metformin on stromal cells were tested at concentrations lower than doses used in experiments showing antitumor effect of this drug [ 46 , 52 , 53 ] .
the antitumor effect of metformin investigated in vitro was established for doses from 5 to 30 mm [ 1 , 46 , 54 ] .
these concentrations of metformin tested on cancer cell cultures are considered as well above the concentration in which metformin can be safely used in vivo [ 30 , 55 ] .
it was shown that the levels of metformin that accumulate in the tissues might be several times higher than in the blood , and thus metformin acts at a significantly higher level in the target organs .
additionally , results of microscopic evaluation of ascs morphology and ultrastructure have shown that high doses of metformin ( 5 mm and 10 mm ) , which were used for in vitro studies , possess a cytotoxic effect on the cells and may cause ( i ) disintegration of cells , ( ii ) nucleus fragmentation and production of apoptotic bodies , ( iii ) enlargement of mitochondria , ( iv ) inhibition of mvs shedding , and ( v ) limited development of cellular projections . to the best of our knowledge ,
this is the first report describing morphological and ultrastructural changes of ascs under the influence of metformin .
however the observations concerning ultrastructural alterations resulting from the metformin action are consistent with the descriptions presented by pounaghi et al . who have noticed shape shrinking and size decreasing of granulosa cells , as well as nuclei shrinking and reduction in number of cytoplasmic organelles and their unnatural appearance .
interestingly , the enlargement of mitochondria observed in ascs treated with 5 mm of metformin is a feature which was noticed also in granulosa cells and nontransformed breast epithelial cells [ 56 , 57 ] .
kiefer et al . have noticed that osteopontin is strongly upregulated in adipose tissue of high - fat diet - induced and genetically obese mice .
our results show that osteopontin expression in adipose tissue of mice treated with metformin decreased in comparison with control group , not receiving metformin .
the decrease of tissue opn expression was correlated with the decrease of other investigated markers of proliferating cells , that is , ki-67 and cd105 .
the downregulation of ki-67 expression resulting from metformin treatment was noted previously in breast and ovarian tumors .
ki - index is highly correlated with cancer progression as it is strongly expressed by proliferating cancer cells .
recently , tebbe et al . have shown that metformin limits adipocyte mediated ovarian cancer cell proliferation , migration , and expression of cancer associated genes and bioenergetic changes .
the inhibition of adipocytes proliferative potential was associated with inhibition of ki-67 expression in differentiating adipocytes .
paper of tebbe et al . supported the thesis that metformin inhibits differentiation of murine preadipocytes , stated previously by the other authors [ 61 , 62 ] .
our results are in good agreement with this postulate , because in the adipose tissue of mice treated with metformin the decrease of cd105 protein expression was noted . moreover , after metformin treatment , we have observed the increased expression of caspase-3 in adipose tissue biopsies .
as it was previously shown , inhibitory effect of metformin on cancer cells may be the result of activation of caspase - dependent apoptosis [ 63 , 64 ] . therefore , obtained results of immunostaining assay show that metformin not only may inhibit self - renewal properties of adipocytes , but also may induce their death . additionally , in our model , the decrease of tissue opn expression after metformin treatment correlated also with decreased levels of this protein in mice serum .
number of human studies reported elevated circulating opn levels in obese individuals compared with lean subjects .
surprisingly , results presented by kiefer et al . and you et al . showed that circulating levels of opn do not correspond with opn expression in adipose tissue of individuals with diet - induced obesity , in both mice and humans .
indicate that local concentrations of opn in adipose tissue may not affect its systemic levels . based on the results obtained in our model
morphometric correlation of adipocytes size from adipose tissue of control and experimental group revealed that metformin treatment significantly decreased diameter and area of adipocytes .
this observation is in a good agreement with ciaraldi et al . and stumvoll et al .
additionally , we noted that metformin may influence adipose tissue composition , due to the fact that adipose tissue of mouse treated with metformin had more heterogeneous structure .
quantitative evaluation of crown - like structures occurring around adipocytes revealed that macrophage infiltration into adipose tissue is similar in both investigated groups of animals .
the fact that metformin may regulate body weight [ 11 , 12 ] was also evident in our model .
moreover , metformin influenced glucose and triglyceride levels causing their decrease ; however , in contrary to previous reports , our results indicate elevated levels of cholesterol in group receiving metformin [ 66 , 67 ] .
in conclusion , metformin affects morphology of adipose - derived multipotent mesenchymal stem cells and adipocytes .
targeting opn expression and synthesis by the metformin action may significantly inhibit proliferation and differentiation of adipocytes and adipocytes precursors .
because obesity , cancer , and aging have numerous interrelationships , the recognition of metformin influence on opn expression may bring a key that will help to tackle epidemics of obesity , diabetes , and cancer .
additionally , dose titration of metformin appears to be crucial , as effects of metformin action strongly relates to its concentration .
an important part of future studies , related to metformin effects on stromal cells , should be a detailed analysis of the mechanisms of its action .
as it was previously noted , the inhibitory effect of metformin on cells proliferation and differentiation may vary among cells .
it seems that a strong clue that will allow for clarification of this issue might be elucidation of ampk role in these cellular processes .
Output:
| metformin is applied not only as antidiabetic drug , but also in the treatment of obesity or as antiaging drug .
the first part of the research discussed the effect of metformin at concentrations of 1 mm , 5 mm , and 10 mm on the morphology , ultrastructure , and proliferation potential of mice adipose - derived multipotent mesenchymal stromal cells ( ascs ) in vitro . additionally , we determined the influence of metformin on mice adipose tissue metabolism .
this study has shown for the first time that metformin inhibits the proliferative potential of ascs in vitro in a dose- and time - dependent manner .
in addition , we have found a significant correlation between the activity of ascs and osteopontin at the mrna and protein level .
furthermore , we have demonstrated that 5 mm and 10 mm metformin have cytotoxic effect on ascs , causing severe morphological , ultrastructural , and apoptotic changes .
the reduced level of opn in the adipose tissue of metformin - treated animals strongly correlated with the lower expression of ki67 and cd105 and increased caspase-3 .
the metformin influenced also circulating levels of opn , which is what was found with systemic and local action of metformin .
the results are a valuable source of information regarding the in vitro effect of metformin on adipose - derived stem cells . |
PubmedSumm6558 | ***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: tbe ( 2,2,2- tribomoethanol 97% , c2h3br3o , mw 282.8 ) , tert - amyl alcohol ( 99% ) and methyl orange were purchased from sigma aldrich , ( st .
hp--cd ( kleptose hpb , mw 1440 ) was obtained from a gift from roquette lestrem , france .
combititrant 5 and methanol ( 99.8% ) were purchased from merck ( auckland , new zealand ) .
atropine was obtained as phoenix atropine injection from provet nz ltd ( christchurch , new zealand ) .
hematoxylin and eosin dyes for histological examination were obtained from surgipath medical ( illinois , usa ) .
tbe is reported to have a solubility of 1 in 40 parts water at 40c , soluble in alcohol , ether , bezene and chloroform and very soluble in tert - amyl alcohol and is supplied as a white crystalline powder .
a 1.25% w / v tbe anesthetic solution was produced following the method recommended by the animal welfare office , university of otago , by dissolving 0.5 g tbe in 0.25 g tert - amyl alcohol then diluting to 40 ml with 0.9% nacl .
dilution of the tert - amyl alcohol solution produced a precipitate , which redissolved with stirring for 30 - 60 min on a magnetic stirrer .
the final solution was filtered ( 0.2 m ) into an amber glass bottle , protected from light by covering the vial with foil and stored at 4c .
the water content of hp--cd samples ( 0.05 g , n = 5 ) was determined by karl fischer titration ( 736 gp titrino , metrohm , usa ) .
the mixture was calibrated with 10 l of distilled water until a consistent value was obtained .
the water content of the hp--cd solid was calculated to be 8.4% w / w .
tbe has no appreciable ultra violet absorbance and so direct measurement of the binding constant for tbe and hp--cd could not be performed .
an approximate phase solubility diagram was constructed by addition of small aliquots ( 5 - 30 mg ) of tbe to hp--cd solutions ( 0 - 0.035 m ) until no further tbe would dissolve .
solutions were protected from light to reduce the risk of chemical degradation during the observation period and stored at 20c .
temperature was monitored using a hobo data logger ( onset computer corp . , bourne , ma , usa ) .
cyclodextrin formulations were prepared aseptically no more than 2 days prior to being used in the animal study .
the cyclodextrin tbe formulation was prepared by dissolving 0.25 g tbe with 0.344 g hp--cd ( weight corrected for water content ) in 20 ml to give a concentration of 1.25% w / v in 0.012 m hp--cd .
this mixture was dispersed using a magnetic stirrer ( ~1 h ) and once fully dissolved , the solution was filtered ( 0.2 m ) and stored at 4c and protected from light until administered .
the procedures described had prior approval from the university of otago animal ethics committee , dunedin and conformed to the university of otago code of ethical conduct for the manipulation of animals ( 1987 ) and the animal welfare act ( 1999 ) in new zealand .
specific pathogen free , adult , female balb / c mice of the same approximate weight ( 19 - 21 g ) were maintained in group housing and acclimatized to the environment for at least 7 days prior to being used in the study .
animals were offered food and water ad libitum , and both were not withheld prior to , or following , anesthesia .
animals were removed from group housing , weighed and placed in individual cages on heating pads to maintain body temperature .
atropine ( 0.05 mg / kg ) was administered subcutaneously 30 min prior to administration of the anesthetic formulations . the cyclodextrin tbe formulation and the standard tbe solution
were compared using the dose regimen of 260 mg / kg tbe administered through the ip route ( n = 6/group ) .
parameters observed in the animals were depth of anesthesia , time to righting reflex loss and gain . the anesthetic efficacy of each formulation was assessed in the mice by monitoring several reflex responses . the time after administration of the anesthetic
to loss of righting reflex , the animal 's reflex to roll onto its front when placed on its back , was recorded .
the intensity of the tail pinch reflex was assessed after pinching the tail of the mouse with plastic forceps .
the intensity of the pedal withdrawal reflex was assessed when the interdigital skin on the fore and hind feet were pinched with plastic forceps .
tail and pedal withdrawal responses were scored on a scale from 0 to 3 ( 0 = no response through to 3 = strong response as in a conscious animal ) . the reflex scores for each time point
were summed to give a combined reflex score ( crs ) of 0 - 9 ( 0 = surgical anesthesia , 9 = fully responsive ) for each animal .
14 days following administration of the anesthetic formulations , a necropsy was performed and tissue samples of the liver and gut were collected for histological examination .
the tissue samples were fixed with 10% formalin , embedded in paraffin and sectioned with a leica rm2025 rotary microtome ( nussloch , germany ) to 3 m thick sections .
statistical analysis was performed using statistical package for the social sciences software ( ibm , version 19 ) .
the comparison between respiratory rate with standard and cyclodextrin tbe formulations was undertaken by repeated measures analysis of variance model .
the time to loss and gain , of righting reflex was compared between the two treatment groups using an independent samples t - test .
tbe ( 2,2,2- tribomoethanol 97% , c2h3br3o , mw 282.8 ) , tert - amyl alcohol ( 99% ) and methyl orange were purchased from sigma aldrich , ( st .
hp--cd ( kleptose hpb , mw 1440 ) was obtained from a gift from roquette lestrem , france .
combititrant 5 and methanol ( 99.8% ) were purchased from merck ( auckland , new zealand ) .
atropine was obtained as phoenix atropine injection from provet nz ltd ( christchurch , new zealand ) .
hematoxylin and eosin dyes for histological examination were obtained from surgipath medical ( illinois , usa ) .
tbe is reported to have a solubility of 1 in 40 parts water at 40c , soluble in alcohol , ether , bezene and chloroform and very soluble in tert - amyl alcohol and is supplied as a white crystalline powder .
a 1.25% w / v tbe anesthetic solution was produced following the method recommended by the animal welfare office , university of otago , by dissolving 0.5 g tbe in 0.25 g tert - amyl alcohol then diluting to 40 ml with 0.9% nacl .
dilution of the tert - amyl alcohol solution produced a precipitate , which redissolved with stirring for 30 - 60 min on a magnetic stirrer .
the final solution was filtered ( 0.2 m ) into an amber glass bottle , protected from light by covering the vial with foil and stored at 4c .
the water content of hp--cd samples ( 0.05 g , n = 5 ) was determined by karl fischer titration ( 736 gp titrino , metrohm , usa ) .
the mixture was calibrated with 10 l of distilled water until a consistent value was obtained .
the water content of the hp--cd solid was calculated to be 8.4% w / w .
tbe has no appreciable ultra violet absorbance and so direct measurement of the binding constant for tbe and hp--cd could not be performed .
an approximate phase solubility diagram was constructed by addition of small aliquots ( 5 - 30 mg ) of tbe to hp--cd solutions ( 0 - 0.035 m ) until no further tbe would dissolve .
solutions were protected from light to reduce the risk of chemical degradation during the observation period and stored at 20c .
temperature was monitored using a hobo data logger ( onset computer corp . , bourne , ma , usa ) .
cyclodextrin formulations were prepared aseptically no more than 2 days prior to being used in the animal study .
the cyclodextrin tbe formulation was prepared by dissolving 0.25 g tbe with 0.344 g hp--cd ( weight corrected for water content ) in 20 ml to give a concentration of 1.25% w / v in 0.012 m hp--cd .
this mixture was dispersed using a magnetic stirrer ( ~1 h ) and once fully dissolved , the solution was filtered ( 0.2 m ) and stored at 4c and protected from light until administered .
the procedures described had prior approval from the university of otago animal ethics committee , dunedin and conformed to the university of otago code of ethical conduct for the manipulation of animals ( 1987 ) and the animal welfare act ( 1999 ) in new zealand .
specific pathogen free , adult , female balb / c mice of the same approximate weight ( 19 - 21 g ) were maintained in group housing and acclimatized to the environment for at least 7 days prior to being used in the study .
animals were offered food and water ad libitum , and both were not withheld prior to , or following , anesthesia .
animals were removed from group housing , weighed and placed in individual cages on heating pads to maintain body temperature .
atropine ( 0.05 mg / kg ) was administered subcutaneously 30 min prior to administration of the anesthetic formulations . the cyclodextrin tbe formulation and the standard tbe solution
were compared using the dose regimen of 260 mg / kg tbe administered through the ip route ( n = 6/group ) .
parameters observed in the animals were depth of anesthesia , time to righting reflex loss and gain .
the anesthetic efficacy of each formulation was assessed in the mice by monitoring several reflex responses .
the time after administration of the anesthetic to loss of righting reflex , the animal 's reflex to roll onto its front when placed on its back , was recorded .
the intensity of the tail pinch reflex was assessed after pinching the tail of the mouse with plastic forceps .
the intensity of the pedal withdrawal reflex was assessed when the interdigital skin on the fore and hind feet were pinched with plastic forceps .
tail and pedal withdrawal responses were scored on a scale from 0 to 3 ( 0 = no response through to 3 = strong response as in a conscious animal ) .
the reflex scores for each time point were summed to give a combined reflex score ( crs ) of 0 - 9 ( 0 = surgical anesthesia , 9 = fully responsive ) for each animal .
14 days following administration of the anesthetic formulations , a necropsy was performed and tissue samples of the liver and gut were collected for histological examination .
the tissue samples were fixed with 10% formalin , embedded in paraffin and sectioned with a leica rm2025 rotary microtome ( nussloch , germany ) to 3 m thick sections .
statistical analysis was performed using statistical package for the social sciences software ( ibm , version 19 ) .
the comparison between respiratory rate with standard and cyclodextrin tbe formulations was undertaken by repeated measures analysis of variance model .
the time to loss and gain , of righting reflex was compared between the two treatment groups using an independent samples t - test .
the solubility of tbe in water is reported to be 1 in 40 ( 2.5% w / v ) at 40c . in the present study
, we observed the solubility of tbe to increase linearly with increasing hp--cd concentration [ figure 1 ] .
the solubility in the absence of hp--cd was 28 mg / ml ( 2.8% w / v ) and temperature recorded over the study period was 21 1.5c .
the al shaped diagram with a slope of greater than 1 suggested a higher order interaction with respect to the drug ( > 1:1 ) exists between tbe and hp--cd . since tbe is a small molecule it is possible that 2:1 or greater molar ratio tbe : hp--cd complex was formed . using equation 1 ,
least squares linear regression produced a slope = 1.608 ( standard error = 0.065 ) ; intercept = 0.1037 ( se = 0.0037 ) ; r = 0.993 where s0 = solubility ( m ) of tbe in the absence of hp--cd and the slope is from the tbe solubility versus hp--cd concentration graph [ figure 1 ] .
a notable difference between the preparations of the formulations was that tbe could be readily dissolved directly in the cyclodextrin solution prior to use , whereas for the standard formulation tbe required dissolution in an organic solvent followed by dilution with normal saline .
when the organic solution was diluted , tbe precipitation was observed and time was required to allow this to re - dissolve prior to use .
the use of cyclodextrin formulations can reduce precipitation in vivo as discussed by brewster and loftsson .
the relationship between the solubility of a drug that forms a complexation with a cyclodextrin is commonly linear .
consequently , upon administration , dilution of the drug - cyclodextrin complex causing dissociation should also occur in a linear fashion , and without precipitation .
this is in contrast to preparations made using organic solvents where the solubilization of the drug is based on a non - linear relationship and so upon dilution following in vivo administration , the ability of organic solvents to solubilize the drug is rapidly reduced leading to precipitation . owing to the disparity in doses reported in the literature ( 125 - 500 mg / kg )
, a preliminary study was undertaken to determine an appropriate dose of tbe to achieve anesthesia in mice .
consistent with other studies , at a dose of 260 mg / kg there was good surgical anesthesia , however there was also some evidence of respiratory depression ( i.e. vocalizations , labored breathing ) .
consequently , atropine was administered 30 min prior to anesthesia ( 0.05 mg / kg ) by subcutaneous injection .
a comparison of anesthesia between the standard tbe solution and the cyclodextrin tbe formulation figure 2 shows the trend for the standard formulation to produce a deeper level of anesthesia , although the difference was not statistically significant .
the lowest crs attained was 0 for the standard formulation and 2 for the cyclodextrin formulation [ figure 2 ] .
short and variable anesthetic times with tbe ( dose 300 mg / kg ) have been reported by avila et al . and
these authors also comment that the duration of anesthesia was sometimes too short to conduct their intended measurements .
the effectiveness of the standard tbe formulation compared to the cyclodextrin formulation may be attributed to the presence of organic solvent ( concentration = 0.625% in the injected solution ) , which is known to cause central nervous system depression and ataxia on its own , and which is not present in the cyclodextrin tbe formulation .
complexation of the tbe with the cyclodextrin would also result in reduced free drug concentrations compared to the standard formulation .
it may be that rather than a comparison of the same dose ( 260 mg / kg ) between the two formulations , a higher dose of the cyclodextrin formulation may be required to have the same effect as the standard formulation .
binding of tbe by hp--cd supports the observation of reduced pharmacodynamic effect in the present study .
however , stella and rajewski reported that release of drugs from cyclodextrin complexes occurs very rapidly once administered to the body .
recovery from the tbe anesthetic was more rapid for the cyclodextrin group as all mice had regained a crs of 9 by 30 min following administration compared to up to 1 h for the standard tbe formulation .
the time to loss and gain of righting reflex reflects the level of anesthesia reached with the two formulations .
results from observation of the righting reflex [ table 1 ] show that this reflex is lost approximately 30 s faster with the standard formulation ( p = 0.006 ) and it appears to take longer to return , although this result was not significant . at a relatively high tbe dose of 400 mg / kg ,
the time interval between loss and regain of righting reflex has reported to be between 0 min and 120 min , with a mean of 21.5 min .
influence of anesthetic formulation on combined reflex score for mice treated with ( a ) standard tribromoethanol or ( b ) hydroxypropyl--cyclodextrin tribromoethanol ( n = 6/group ) . dose of tribromoethanol was 260 mg / kg + atropine 0.05 mg / kg .
crs score 0 = surgical anesthesia and 9 = fully responsive comparison of times to loss and gain of righting reflex between the standard tribromoethanol formulation and hydroxypropyl--cyclodextrin tribromoethanol formulation variable anesthetic effect is reported in the literature for tbe and comparisons may be confounded by the variety of doses used , animal characteristics ( age , sex and species ) and method of assessment of anesthesia .
for example , a gender difference is reported for tbe with female mice having longer durations of anesthesia .
the current experiments were performed to reduce sources of variability by using an inbred strain of mice , one gender ( females ) of similar age and weight and performing the experiments at the same time of day to reduce variation due to circadian rhythm .
it is also noted in the present study that there was considerable individual variation in response to the anesthetic , with the group of mice that received the cyclodextrin formulation showing less variation [ figure 2 ] .
the observed differences in response following the injection of tbe could be in part due to the variable placement of the ip injection within the peritoneum .
injection of the formulations adjacent to gut vasculature may lead to a more rapid and higher absorption , as diffusional distances for tbe are less .
such variability in absorption of substances from the peritoneal cavity is known to vary between subjects , as has been seen with the peritoneal absorption of insulin in humans .
there has also been criticism of the use of the ip route as it is easy to cause damage to the intestine and visceral organs during administration of the injection .
the use of a cyclodextrin formulation instead of one that includes an organic solvent may make it feasible for administration to be performed subcutaneously rather than the ip route ; however the suitability of the subcutaneous site for tbe remains to be investigated .
some researchers report high rates of post - anesthesia mortality , peritonitis , intestinal ileus and abdominal adhesions , whereas others have used tbe extensively with few adverse effects .
the mice in the current study were monitored daily for 14 days after administration of the anesthetic for clinical signs of illness , i.e. weight loss , reduction in water intake , abnormal behavior . at day 14
no evidence of inflammation or gross lesions was identified in the abdominal cavity of the animals .
tissue samples were taken from the spleen , kidney , bowel and liver for histological examination .
there was no evidence of inflammation or fibrosis found in any of the tissues examined and there was no difference between the two tbe formulations investigated [ figure 3 ] .
norris and turner investigated the use of tbe in mongolian gerbils at varying concentrations ( 1.25 - 2.25% ) and doses ( 225 - 450 mg / kg ) and found that mortality rate increased with the use of the 2.25% solution and at higher doses for the 1.25% solution .
the use of the lower concentration ( 1.25% ) solution and the relatively low dose rate in the present study may be a contributing factor why no inflammation was observed in the tissues .
in addition , the absence of pathological findings may be because of the period of time between the animals receiving the formulation and the euthanasia .
the post mortem conducted 14 days after anesthetic administration may have provided time for any inflammation to resolved , however thompson et al
. investigated histopathological changes to the liver , spleen , heart and kidney 3 and 6 h after the onset of anesthesia following an ip injection of tbe in mice ( dose 160 mg / kg ) and also report no detectable pathologic changes in the tissue .
photomicrographs of bowel section from mice administered ( a ) standard tribromoethanol formulation and ( b ) cyclodextrin tribromoethanol formulation .
sections of liver parenchyma 14 days after administration of ( c ) standard tribromoethanol formulation and ( d ) cyclodextrin tribromoethanol formulation .
v = vein , hepatocyte nuclei are stained a blue / black colour ( arrow ) and red blood cells visible in the sinusoids
tbe could be formulated as a 1.25% w / v solution 0.035 m hp--cd in a single step without the need for an organic solvent .
this study has also identified the value in using atropine in addition to tbe for anesthesia .
the reduced anesthetic effect of the cyclodextrin formulation compared to the standard formulation may have been due to tbe complexation with the cyclodextrin complex .
no evidence of peritonitis or abdominal adhesions were observed with either formulation , suggesting that freshly prepared tbe solutions ( standard or hp--cd ) at a concentration of 1.25% were not significantly irritant .
Output:
| objective : efficacy and safety concerns have been raised in the literature with the use of tribromoethanol ( tbe ) ( avertin ) for anesthesia in rats and mice when administered by intraperitoneal ( ip ) injection . despite the controversy , it remains in common usage as an anesthetic agent in laboratory rodents for short - term surgical procedures .
cyclodextrins have been shown to improve drug solubility and were investigated here as an improved anesthetic formulation for mice.materials and methods : the phase solubility of tbe with hydroxypropyl--cyclodextrin ( hp--cd ) was estimated .
the efficacy of two anesthetic regimens was compared in this study ; the conventional tbe formulation solubilized in tert - amyl alcohol and a hp--cd formulation containing tbe .
mice ( n = 6 ) were administered the formulations by ip injection and the pharmacodynamic parameters of time to induction of anesthesia , duration of anesthesia and recovery time were measured using a combined reflex score ( crs).results and discussion : phase solubility studies showed a linear increase in the solubility of tbe with increasing hp--cd concentration and suggested > 1:1 binding of the drug in the cyclodextrin complex . at a dose of 260 mg
/ kg the standard tbe formulation appeared to produce deeper anesthesia than the cyclodextrin formulation , with a minimum average crs of 1.8 compared with 5.2 .
no post - mortem pathology was observed in mice that received either the conventional or cyclodextrin formulation.conclusion:the cyclodextrin tbe formulation did not conclusively provide an improved anesthetic response at a dose of 260 mg / kg compared with the conventional formulation .
the improved solubility of tbe with hp--cd and the reduced variability in anesthetic response warrants the further investigation of this formulation .
this study has also identified the value of using the anticholinergic atropine in association with tbe for anesthesia . |
PubmedSumm6559 | ***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 percentage of elderly people has increased from 11.4% in 1984 to over 18% in 2011 and is estimated to reach 35% in 2050.1 today , 3.5% of those over 65-years old are aged over 80 ; since 1984 the number has increased from 1.2 million to 2.4 million and in 2050 this will reach 5 million;1 of these , 50% will be suffering from concurrent diseases and will be chronically disabled .
frail elderly patients whose health is worsening usually seek care from a general practitioner and then , in the case of complex clinical care , to the service network ( specialist s and home visits , nursing home , hospital , and so on ) .
a significant percentage of elderly subjects ( 50%80% ) with chronic ischemic cerebrovascular disease with or without moderate - to - severe cognitive decline , and with or without behavioral and psychological disorders , show complex symptoms related to the progressive deterioration of their general state of health and/or to situations causing an increase in stress ( eg , institutionalization ) .
symptoms are characterized by confusion and/or stupor , which are difficult to manage clinically and require a great deal of care .
the percentage of elderly people has increased from 11.4% in 1984 to over 18% in 2011 and is estimated to reach 35% in 2050.1 today , 3.5% of those over 65-years old are aged over 80 ; since 1984 the number has increased from 1.2 million to 2.4 million and in 2050 this will reach 5 million;1 of these , 50% will be suffering from concurrent diseases and will be chronically disabled .
frail elderly patients whose health is worsening usually seek care from a general practitioner and then , in the case of complex clinical care , to the service network ( specialist s and home visits , nursing home , hospital , and so on ) .
a significant percentage of elderly subjects ( 50%80% ) with chronic ischemic cerebrovascular disease with or without moderate - to - severe cognitive decline , and with or without behavioral and psychological disorders , show complex symptoms related to the progressive deterioration of their general state of health and/or to situations causing an increase in stress ( eg , institutionalization ) .
symptoms are characterized by confusion and/or stupor , which are difficult to manage clinically and require a great deal of care .
citicoline ( cdp - choline and choline or cytidine-5-diphosphate choline ) works as an intermediate compound in the biosynthesis of cell membrane phospholipids and has got cholinergic and neuroprotective actions.24 cdp - choline ( cytidine-5-diphosphate choline ) is an essential precursor for the synthesis of phosphatidylcholine , a component of the cell membrane that , during cerebral ischemia , is degraded into fatty acids and free radicals.24 this was widely demonstrated in animal models which have shown that cdp - choline may protect cell membranes by accelerating phospholipid resynthesis.5 it can also reduce the progression of cell ischemic damage by suppressing the release of free fatty acids.6 cdp - choline supplementation has been shown to play an important protective role in case of vascular damage and neurodegeneration , whereas in aging , normal rats there was no improved effect on memory .
therefore , these findings suggest that young rats with long - term memory impairment , due to selective hippocampal damage , benefit from a dietary supplementation of cdp - choline.5 cdp - choline is an endogenous compound normally produced by the body ; when it is introduced as a drug , it is called citicoline.7 citicoline inhibits apoptosis associated with cerebral ischemia and several models of neurodegeneration and it is able to strengthen neuroplasticity.7 citicoline : activates the biosynthesis of phospholipids in neuronal membranes increases brain metabolism increases norepinephrine and dopamine levels in the central nervous system has neuroprotective effects during hypoxia and ischemia improves learning and cognitive performance in animal models of brain aging protects atpase activity of mitochondrial and membrane na / k atpase inhibits phospholipase a2 activation and accelerates the reabsorption of cerebral edema in various experimental models.6 in some studies of patients with head trauma , citicoline has shown its capability at accelerating recovery from posttraumatic coma ( including the ability to walk ) , reaching better functional outcomes , reducing the duration of hospital stays , and to the improvement of memory and cognitive impairment.6 in the treatment of patients with acute ischemic vascular disease , citicoline accelerates the recovery of consciousness and motor deficits , facilitating the rehabilitation of these patients.4,810 another important use of cdp - choline is in the treatment of cognitive impairment secondary to age - related degenerative diseases ( eg , alzheimer s disease ) and chronic cerebrovascular disease.2,3 in patients with chronic cerebral ischemia the use of cdp - choline has been shown to improve scores on cognitive evaluation ranges , while in patients with alzheimer s senile dementia , it slows down disease progression .
beneficial neuroendocrine , neurophysiological , and neuroimmunomodulatory effects in parkinson s disease have also been reported , thanks to its indirect dopamine - agonist effect.1114 the evidence is definitely strong , although limited by the duration of studies , so it would be appropriate to perform more long - term studies . moreover , it can be assumed that long - term treatment is safe because serious side effects have never been reported . on the other hand , citicoline has no significant systemic cholinergic effects.6 therefore , we can summarize that citicoline may be used in cerebrovascular diseases , head trauma , cognitive disorders of different etiology , glaucoma , parkinson s disease , and amblyopia .
the aim of the present study was to evaluate the safety , tolerability , and efficacy of citicoline in geriatric syndrome8 with a complex clinical picture of confusion on a retrospective and observational basis .
the study involved ten centers throughout the country performing both geriatric surgery and home visits . over 65-year - olds with moderate to severe neurological deficits due to cerebral ischemia
were enrolled.9,10,15,17 the following scales were administered : the national institute of health stroke scale ( nihss),1921 rankin scale ( modified version ) , and barthel index.16,18 the enrolled patients needed to have nihss 814/>15 , rankin scale 45 , and barthel index 4020/<20 .
those enrolled were people with progressive worsening of their cognitive health and general confusion and/or stupor ( requiring the intervention of a geriatrician either in a nursing home or for home visits ) .
the study was divided into three phases in a period of 6 months ( table 1 ) . during the first phase ( t1 ) , which lasted 4 months ,
patients were enrolled and treated with 2000 mg of citicoline through a slow intravenous infusion in 500 cc of saline for 5 days , to be repeated for 5 more days in the case of nonresponders . in the second phase ( t2 ) , after clinical reassessment and verification of side effects and tolerability , ( step a ) treatment with 1000 mg of intramuscular citicoline was administered and it was repeated for 21 days ( step b ) after a 7 day interruption . during the third and final phase ( t3 ) the results were evaluated .
the nihss , the rankin scale , the scale of independence in activities of daily living ( adl ) , and the scale of independence in instrumental activities of daily living ( iadl ) were identified as tools for assessing deficits in autonomy , for their validity , reliability , and quick performance .
demographic and clinical information about the patients included in the study were collected in forms filled in during the described phases and conveyed to a central database .
the statistical processing of such data was made through the use of spss ( ibm , armonk , ny ) .
a total of 272 subjects were enrolled . of these , 197 subjects ( 72% ) were recruited and completed treatment and assessment , ( 43.1% men , 57.9% women ) , of which 55 ( 20% ) were given the treatment provided during stage t1 , step b ( figure 1 ) .
a total of 75 patients ( 27% ) dropped out of the study , five ( 1.8% ) refused to continue treatment , and 70 ( 25% ) gave up the study protocol or dropped out for other reasons .
frequency analysis by age group ( table 2 ) shows five subjects ( 2.5% ) aged 6069 years , 78 subjects ( 39.6% ) aged 7079 years , 106 subjects ( 53.8% ) aged 8089 years , and eight subjects ( 4.1% ) over 90 years old .
the sample distribution by age group was conditioned only by the time limit of the first phase of recruitment and , therefore , features a real sample , which turns out to be better represented by the group of subjects aged 8089 years .
the analysis of diseases detected on history is confirmed by epidemiological data in literature , and hypertension seems to be the most represented risk factor .
the association of dementia - hypertension- non - insulin dependent diabetes mellitus and coronary artery disease seem to exacerbate the development of this syndrome ( table 3 ) .
the results were compared with a control group whose mean age was 86.7 years standard deviation ; it included eight men ( 54% ) and seven women ( 46% ; table 2 ) . the control group was treated with intravenous administration of saline ( 500 cc ) and glucose 5% ( 500 cc ) and limited to 15 cases where treatment did not seem to result in significant clinical improvement . in particular , mean
nihss score was 19 and 18.2 during t1 and t3 respectively , mean rankin score was 4.7 and 4.5 during t1 and t3 respectively , mean adl was 0.5 and 0.7 during t1 and t3 respectively , and mean iadl was 0.0 and 0.3 during t1 and t3 respectively ( table 4 ) .
the comparison with the sample group certainly indicates more favorable outcomes in the treated group , even though the small sample size of the controls does not provide a statistically significant difference ( table 5 ) .
data analysis of the nihss scale by age group shows an improvement in all phases and in all age groups .
the positive results are particularly evident from t1 to t2 : many of the starting values were higher and the age group was lower ( 6069 years old ) .
however , our results were also significant in the oldest age groups , because of age - related medical conditions ( figure 2 ) . in short
, the data must be read considering both the age group s starting point and its therapeutic - rehabilitative goals .
the assessment with the rankin scale shows a reduced improvement in self - sufficiency in those aged 7079 years and 8089 years , whereas changes in the first and last age groups are negligible . in this case , too , the assessment must consider the starting values since the study samples rankin values already showed the presence of moderate to severe disabilities which can hardly regress ( figure 3 ) .
even adl data ( figure 4 ) displayed a positive trend in the performance of functional independence in the sample group aged over 90 years old .
the examination of the final results shows statistical significance , confirming the efficacy of citicoline in the complex geriatric syndrome complicated by confusion due to the worsening of general health conditions for the nihss during t1t2 , the rankin scale during t1t2t3 , and adl scale during t1t2 . there was no significance in iadl scores .
however , the lack of statistical significance of our data , compared to a positive trend , requires further studies and a larger sample size .
in sub - acute ischemic cerebrovascular disease , administration of citicoline at the intravenous dose of 2000 mg in 500 cc of saline for 5 days or 10 days has proven to be effective in improving functional independence and in reducing the burden of care .
after 5 days ( 80% of cases ) , or 10 days ( 20% of cases ; t2 ) , or 2 months ( t3 ) since the beginning of treatment , there was an improvement in key measures of performance .
the most important and significant positive impact was evident in the results of the oldest age groups .
there were no major side effects in any phase of the study , so we can conclude that citicoline at the commonly used dosages is safe and well - tolerated .
the association dementia hypertension non - insulin dependent diabetes mellitus coronary artery disease is very much related to the development of complex geriatric syndrome complicated by confusion , and this leads us to reflect on the need for aggressive preventive therapies in advanced age too .
the presence of dementia is associated with cardio - cerebrovascular risk factors and the reconsideration on epidemiological data of degenerative dementias .
the complex geriatric syndrome is significantly related to a condition of frailty that is , in turn , related to age .
the results must consider the poor sample size , the short follow - up , and its features of being a retrospective and observational study .
Output:
| a significant percentage of elderly subjects ( 50%80% ) suffering from sub - acute ischemic cerebrovascular disease , with or without moderate or severe cognitive memory decline and with or without associated behavioral and psychological symptoms , shows a complex syndrome .
this syndrome is related to the progressive impairment of health conditions and/or stressing events ( ie , hospitalization ) , characterized by confusion and/or stupor , which are consequently difficult to manage and require a great deal of care .
geriatric patients often suffer from multiple chronic illnesses , may take numerous medications daily , exhibit clinical instability , and may experience worsening of medical conditions following cerebral ischemic events and thus have an increased risk of disability and mortality .
there are several studies in literature which demonstrate the efficacy of citicoline , thanks to its neuroprotective function , for the recovery and in postischemic cerebral rehabilitation .
it has been shown that , even soon after an ischemic stroke , administration of oral citicoline ( 5004000 mg / day ) improves the general conditions evaluated with the rankin scale and the national institute of health stroke scale 12 . in particular , it has been shown that the cdp - choline improves the cognitive and mental performance in alzheimer s dementia and vascular dementia .
we have evaluated the administration of citicoline in geriatric patients following a protocol of intravenous study on improvement of individual performances . |
PubmedSumm6560 | ***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: urethral diverticular adenocarcinoma is a rare cancer found in female patients , presenting only 5% of female urothelial cancers .
we report a case of a urethral diverticular adenocarcinoma after the fenestration of the anterior vaginal wall for pelvic floor abscess .
a 61-year - old woman presented to the gynecology department with complaints of atypical genital bleeding .
magnetic resonance imaging ( mri ) revealed a localized urethral tumor extended to vagina ( fig . 1 ) .
computed tomography did not reveal any evidence of metastasis . under the diagnosis of urethral tumor , the patient was referred to our department . because the fenestration of the anterior vaginal wall was performed under the diagnosis of the abscess in the pelvic floor for the patient 15 years ago and the histological test demonstrates the adenocarcinoma , we suspected a urethral diverticular adenocarcinoma .
figure 1:sagittal t2-weighted mri of the pelvis revealed a localized urethral tumor extended to vagina .
sagittal t2-weighted mri of the pelvis revealed a localized urethral tumor extended to vagina . on admission , we performed standard open total cystectomy with lymph node excision and ileal conduit .
the resected specimen showed the mass on the anterior vaginal wall ( fig . 2 ) .
histopathological examination of the specimen showed adenocarcinoma tumor that continues to anterior vaginal wall , but urethral diverticular wall could not be identified ( fig .
we could not establish a diagnosis of urethral diverticulum ; however , we clinically diagnosed as urethral diverticular adenocarcinoma .
the proximal margin was negative , and all lymph nodes were negative . because the post - surgical course was uneventful , the patient was discharged from our hospital on day 27 post - surgery .
figure 3:histopathological examination of the specimen showed adenocarcinoma tumor which continues to anterior vaginal wall , but urethral diverticular wall could not be identified .
histopathological examination of the specimen showed adenocarcinoma tumor which continues to anterior vaginal wall , but urethral diverticular wall could not be identified .
, there are less than 60 reported cases of urethral diverticula carcinoma , including adenocarcinoma and squamous cell carcinoma .
urethral bleeding is the most common presenting symptom , occurring in 51% patients . a painless growth , found initially as either an anterior vaginal mass or a urothelial obstruction , was present in 24% patients
therapy for urethral diverticular carcinoma consists of local excision such as diverticulectomy or more aggressive therapy such as definitive radiation therapy or radical cystourectomy with pelvic lymph node dissection . in our case , it is possible that drainage treatment was performed for urothelial diverticulum 15 years ago .
patients with urethral diverticula often present with a variety of nonspecific lower urinary symptoms such as frequency , urgency , localized pain or dysuria . approximately 4% cases of female urethral diverticulum cause urinary retention . an asymptomatic patient with urethral diverticulum can be managed by observation . on the other hand ,
the first and most common choice of treatment for symptomatic urethral diverticulum is complete vaginal excision .
however , because of several risks and the high recurrence rate of complete vaginal excision , we have advocated that the management by transvaginal drainage could be the appropriate treatment for urethral diverticulum on the past published case report .
this procedure is effective and conservative with few complications , but we should not forget very rare cases of carcinoma arising in urethral diverticula have been reported . in this case , if the urethral diverticulum had removed completely 15 years ago , the generation of malignant tumors might have been avoidable .
anyway , for the patient with urethral diverticula , close long - term follow - up for the recurrence or generation of malignant tumors by genitourinary examinations or images is necessary .
Output:
| a 61-year - old woman presented to the gynecology department with complaints of atypical genital bleeding . magnetic resonance imaging revealed a localized urethral tumor extended to vagina .
histological test of the biopsy tissue of the mass suggested the adenocarcinoma .
the patient was performed the fenestration of the anterior vaginal wall 15 years ago . under the diagnosis of urethral diverticular adenocarcinoma , we performed standard open total cystectomy with lymph node excision and ileal conduit .
we could not establish a diagnosis of urethral diverticulum from the histological test ; however , we clinically diagnosed as urethral diverticular adenocarcinoma . because carcinoma arising from urethral diverticula is reported , a close long - term follow - up for the recurrence or generation of malignant tumors by genitourinary examinations or images is necessary , for the patient with urethral diverticula . |
PubmedSumm6561 | ***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: joint contracture occurs when joint movements are reduced , such as by immobilization of a
joint with a plaster cast , orthosis , or after prolonged bed rest .
several conditions limit
the range of motion ( rom ) of joints , including cerebrovascular diseases , neuromuscular
diseases , bone and joint diseases , and various other diseases .
contracture may be classified into three groups : arthrogenic , myogenic , and soft
tissue1 .
arthrogenic contracture is
caused by immobility caused by damage and inflammation of cartilage , synovial tissue , and
joint capsule .
soft
tissue contracture occurs because of pathological shortening of connective tissue , including
the skin , subcutaneous tissue , tendons , and ligaments .
examples of intrinsic causes include
trauma , inflammation , degenerative changes , and ischemia .
examples of extrinsic causes
include spasticity , flaccid paralysis , malpositioning , and immobilization .
many investigators have studied the pathogenesis of contracture in dogs , monkeys , rats , and
other experimental animals .
these studies provided evidence of a relationship between the
period of immobilization and rom limitation factors , and changes in joint components and
soft tissue , including muscle and skin . in addition , decreases in mobility and plasticity of
the nervous system are considered to cause rom limitation2 .
nervous system mobilization is used as a physical therapeutic
approach to improve such conditions .
it uses palpation or joint movements to initiate
physical or physiological changes in blood flow or the axonal flow of nerves , aiming to
improve the plasticity of the nerve3 . in
addition
, nervous system mobilization has been reported to be effective at improving rom
limitation and pain , and induces the largest longitudinal excursion of the nerve relative to
its surrounding structures without being associated with a potentially detrimental increase
in nerve strain4,5,6 . on the other hand ,
there is
no evidence that mobilization of neural tissue , independent of other anatomical structures ,
would be feasible in living people , or that nervous system mobilization is effective in the
treatment of musculoskeletal dysfunction .
therefore , it is still unclear whether nervous
system mobilization is effective7,8,9,10 . as stated above , nervous system mobilization is used to improve rom limitation and other
conditions , but the changes that it causes in the nerves and the periphery in contracture
arising from secondary disabilities or prolonged bed rest remain unclear .
the present study was
performed to determine changes in the tissue located in the periphery of the sciatic nerve
during contracture in an animal model .
immobilization model male wistar rats ( 9 weeks old , n = 29 , weight 240 280 g ) were divided randomly into a
control group ( c group , n = 7 ) and immobilized group ( i group , n = 22 ) , and were kept in
plastic cages for 2 weeks .
the rats had unlimited activity in the cage and free access to
food and water .
the animal room was maintained at a constant temperature of 22 c , and the
animals were maintained under a 12-h light / dark cycle to avoid effects arising from the
biological rhythm of the rats .
this experiment was performed in accordance with the
guidelines for the care and use of laboratory animals of kanazawa university and the
protocol for this experiment was approved by the animal research committee of kanazawa
university .
rats in i group had the left knee joint immobilized for 2 weeks in the posture of maximum
flexion with a plaster cast of our own making and aluminum wire netting .
the casts were
applied under deep anesthesia induced by intraperitoneal injection of pentobarbital sodium
( 40 mg / kg ) ( fig .
care was taken to avoid
disturbance of blood flow to the hip and ankle joints due to pressure from the cast . during
the immobilization period
, wounds and edema were prevented and if the plaster cast came off
immobilization was repeated again as soon as possible .
animals in c group were given food ad
libitum , and had no restrictions placed on their mobility .
at the end of the immobilization period , the rats were euthanized with diethyl ether and
both hip joints were disarticulated immediately .
the joint tissue was fixed with 10%
formalin neutral buffer solution for 72 h decalcified in edta at 4 c for 72 h. after
decalcification , the specimens were cut vertically at the center of the femur and
neutralized with 5% sodium sulfate for 72 h , and then embedded in paraffin .
the embedded
paraffin blocks were cut into sections at a thickness of 3 m .
we examined the periphery of the sciatic nerve under an optical microscope ( bx51 ; olympus ) .
the software
program jmp7 ( sas institute japan inc . ) was used for statistical analyses , and values of p
< 0.05 were accepted as statistically significant .
the perineural space ( black arrows ) can be seen between the
bundle of nerve fibers and the perineurium ( dotted arrows ) .
adherence between the bundle of nerve fibers and the
perineurium ( black arrows ) , and thickening of the perineurium ( dotted arrows ) were
observed .
scale bar : c : 500 m , d : 200 m . in c group ,
the bundle of nerve fibers tended to separate from the perineurium , and a space
was clearly observed between the bundle of nerve fibers and the perineurium ( fig . 2 and table
1 ) .
conversely , in the rats of i group , strong adherence between the bundle of
nerve fibers and perineurium was observed in 19 of 22 animals ( fig .
3 and table 1 ) , and
thickening of the perineurium was detected in 20 of 22 of these rats ( fig . 3 and table 2 ) .
generally , peripheral nerves consist of several bundles of nerve fibers . in these bundles
of nerve fibers , each nerve fiber , including the schwann cells enveloping it , is surrounded
by endoneurium that consists of areolar connective tissues containing blood vessels . each
bundle of nerve fibers is covered by perineurium , which is a dense layer composed of
collagenous connective tissue enveloped by 7 or 8 layers of squamous epithelial - like
cells11 .
there is a space between the
perineurium and the bundle of nerve fibers , but there have been no previous anatomical
descriptions of this space .
peripheral nerves consist of more than one bundle of nerve
fibers and the epineurium consisting of areolar connective tissues .
the bundles of nerve
fibers are combined with each other and form a nerve trunk , with a cylindrical strong
connective tissue sheath12 .
the sciatic nerve is the largest nerve in humans and represents most of the nerve fibers
forming the sacral plexus .
this nerve descends into the posterior compartment of the thigh from the gluteal region
through the greater sciatic foramen .
proximal to the knee , and sometimes within the pelvis ,
the sciatic nerve divides into its two terminal branches , the tibial nerve and the common
fibular nerve .
it innervates all muscles in the posterior compartment of the thigh , lower
leg , and foot , as well as most of the skin of the lower leg and foot13,14,15 .
the spinal nerves in the rat consist of 34 pairs of
nerves : 8 cervical , 13 thoracic , 6 lumbar , 4 sacral , and 3 caudal .
the sacral plexus in the rat is
more limited in the extent of its origin than the human one .
it is formed by the fifth , and
the adjacent parts of the fourth and sixth lumbar nerves .
the sciatic nerve divides into its
two terminal components , the common fibular nerve and the tibial nerve , which in their
course through the thigh cross the obturator externus , quadratus femoris , and adductor
magnus , lying between these muscles and biceps femoris , until they reach the popliteal fossa
where they separate .
as described above , the sciatic nerve tract in the rat is almost the
same as in humans16 .
the nervous system adapts to lengthening in two ways , movement and elongation2 , 3 .
movement may be considered as gross movement or movement occurring intraneurally between the
connective tissues and the neural tissues .
gross movements refer to movement of the system
as a whole in relation to the connective tissue interface .
a peripheral nerve sliding
through a tunnel , such as the median nerve , is a clear example of this type of gross
movement .
intraneural movement refers to movement of the neural tissue elements in relation
to the connective tissue interfaces .
the brain or the spinal cord can move in relation to
the dura mater and a fascicle can slide in relation to another fascicle in peripheral
nerves . on the other hand , elongation is like elastic gum and the nervous system adapts to
joint movement by increasing intraneural pressure or intradural pressure .
the looseness of
nerve fibers , epineurium , and perineurium decrease as the nerve is elongated .
the epineurium
is only slightly involved in resisting elongation of the nerve , and resistance is mainly
offered by the perineurium .
reductions in these adaptations induce limitation of rom , pain ,
and neurological symptoms .
generally , nervous system mobilization can increase the mobility
of the nerve by improving the motility and extensibility of the nervous system when movement
and elongation are reduced due to the influence of various factors , but there is no
histological evidence of such an effect . in this study , a space was observed between the bundle of nerve fibers and the perineurium
of the sciatic nerve in the c group .
it is possible that this space is an artificial
histopathological image caused by differences in the rate of contraction between the bundle
of nerve fibers and perineurium tissue in the process of specimen preparation .
however , in i
group this space was not observed , so , we considered it unlikely that this was an artificial
image appearing only in i group .
there have been no anatomical descriptions of this space and it has not been the focus of
prior study .
however , in pancreatic cancer , gastric cancer , and prostate cancer , the
invasion of cancer tissue into this space ( perineural invasion ) has been seen ; therefore ,
this space has attracted attention and is known as the perineural space .
watanabe17 reported that cancer cells do not invade
bundles of nerve fibers , but scatter along loose connective tissue in the perineurium .
the
results of experimental and clinical studies indicate that the perineural space is
independent of the lymphatic system and there is no traffic between the two18 , 19 .
in addition , miyazaki20 reported that perineural invasion shows continuous tumor spread ,
unlike lymphatic invasion and vein invasion , and there is no flow in the perineural space ,
unlike lymphatic and blood vessels .
as mentioned above , it is clear that there is a space
between the bundle of nerve fibers and the perineurium of autonomic nerves .
however , there
have been no previous reports of its presence in somatic nerves and its physiological
significance remains unknown .
further studies and descriptions of the perineural space have
not been reported to date . in c group ,
the bundle of nerve fibers separated from the perineurium physiologically , and
there was a perineural space in the periphery of not only the autonomic nerve , but also the
somatic nerve . on the other hand
, there was no perineural space in i group : the bundle of
nerve fibers tended to make contact with the perineurium , and there was the possibility of
adhesion between the two .
with regard to this adhesion , if the perineurium functions as a
buffer between the bundle of nerve fibers and the peripheral tissue of the nerve , it is
possible that this adhesion decreased the mobility and plasticity of the bundle of nerve
fibers .
thomas21 reported that the
perineurium acts as a mechanical barrier to external forces , and sunderland22 reported that it was the structure most
resistant to tensile forces .
we suggest that thickening disturbs these functions of the
perineurium , causing a decrease in the buffer function and the mobility and plasticity of
the nerve .
this is the first study to examine the changes in the periphery of nerve tissue
after joint immobilization with histopathological observations . in conclusion
, abnormal histopathological images were observed in not only the joint
components and soft tissue , but also in the peripheral tissue of nerves in the rat knee
joint contracture model indicating joint immobilization may affect the peripheral tissue of
nerves .
Output:
| [ purpose ] this study was performed to investigate the histological changes that occur in
the periphery of the sciatic nerve in rats undergoing knee immobilization .
[ subjects and
methods ] 29 male 9-week - old wistar rats were divided randomly into a control group ( c
group , n = 7 ) and an immobilized group ( i group , n = 22 ) .
the animals in the i group had
the left knee joint immobilized in maximal flexion with plaster casts for two weeks .
after
the experimental period , we obtained cross - sections of tissues from the center of the left
thigh , and the periphery of the sciatic nerve was observed under an optical microscope
after hematoxylin - eosin staining .
[ results ] in contrast to the rats of c group , the rats
in i group showed adherence between the bundle of nerve fibers and perineurium , as well as
thickening of the perineurium .
these histological changes were statistically significant .
[ conclusions ] immobilization of the knee joints of rats resulted in characteristic
histological changes in the connective tissue around the sciatic nerve . |
PubmedSumm6562 | ***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: subjects for this study were identified from an institutional review board approved clinical registry of all ischemic strokes at the new york - presbyterian hospital / weill cornell medical center , a tertiary - care hospital and certified primary stroke center .
all patients admitted to our hospital s stroke service with ischemic stroke during 2013 were prospectively included in a database that is part of the aha s get with the guidelines stroke national registry.9 the get with the guidelines data collection was performed using a standardized template to collect clinical data on consecutively admitted stroke patients.9 ischemic stroke was determined by inpatient vascular neurologists using the aha s definition10 of an episode of neurologic dysfunction caused by focal brain ischemia , based on either imaging evidence of infarction in a defined vascular distribution or clinical symptoms persisting > 24 hours .
trained hospital personnel collected information about the national institutes of health stroke scale upon presentation , prior stroke history , inpatient hospital diagnostic studies performed , and demographic characteristics .
in addition , the presence of the following vascular risk factors was also recorded : active tobacco use , diabetes ( defined as a hemoglobin a1c of > 6.5% or on diabetes medication ) , insulin use , hypertension ( blood pressure > 140/90 mm hg or on antihypertensive medication ) , atrial fibrillation , dyslipidemia ( low - density lipoprotein > 100 mg / dl or on statin therapy ) , coronary heart disease , and cardiac valvular disease . for subjects included in this prospective registry , 2 vascular neurologists , using all available medical data , independently assigned stroke etiology using the toast classification scheme.11 disagreements in subjects stroke subtype classification were adjudicated by a third vascular neurologist .
once this cohort of ischemic stroke patients was identified , the following additional inclusion criteria were applied : ( 1 ) ischemic stroke of undetermined source per the toast classification , ( 2 ) mri of the brain and mra of the neck ( including 3d and 2d tof sequences ) performed during the inpatient admission , and ( 3 ) mri evidence of diffusion - weighted imaging ( dwi)positive , unilateral anterior circulation infarct(s ) .
we also applied the following exclusion criteria : ( 1 ) bilateral or posterior circulation acute , dwi positive infarcts on mri ; and ( 2 ) evidence of carotid artery stenosis > 50% on sonography , computed tomography angiography , or mra as per north american symptomatic carotid endarterectomy trial criteria.1 in a sensitivity analysis , we additionally excluded patients who were classified as having a stroke of undetermined source because of the presence of 2 or more potential stroke causes , thereby focusing on patients with truly cryptogenic stroke .
all neck mra studies were performed on either 1.5 or 3.0 t signa ( general electric ) scanners using standard quadrature neck array coils . of note , neither high - resolution surface carotid coils nor gadolinium were used for these examinations , which were performed during the acute stroke workup .
the 3-minute 3d - tof acquisition involved a 20-cm field - of - view centered at the carotid artery bifurcation and included a 1.4-mm slice thickness and matrix of 320192 and 320224 on 1.5 and 3 t , respectively , yielding pixel sizes of 0.6 mm . because we aimed to assess the generalizability of this technique to routine clinical practice , no studies were excluded for patient motion artifact , and all studies with image quality sufficient to generate a clinical interpretation at the time of original image acquisition
dwi - positive lesions were also categorized in terms of whether the cerebral cortex was involved .
intraplaque high - intensity signal ( ihis ) on axial 3d - tof images was used as a presumed marker for intraplaque hemorrhage.12,13 we used a previously published method12,1416 in which hyperintense signal intensity in carotid plaque is assessed using region - of - interest analysis compared to background sternocleidomastoid muscle signal intensity . in those patients with visible nonhemodynamically stenosing plaque on tof images , we used a quantitative cutoff of signal intensity 50% greater than skeletal muscle based on region - of - interest analysis in the area of suspected ihis.1416 we took care to clearly delineate ihis from perivascular fat outside of the vessel by classifying a case as ihis - positive only when high signal occurred specifically at the site of a presumed atherosclerotic plaque , which we required to be detectable as a region of focal eccentric luminal narrowing seen on contiguous axial images .
such an effort minimized the chance that high - signal fat outside of the vessel would be mistaken for the intraplaque hemorrhage for which ihis is a surrogate.14 furthermore , we made an effort to avoid misclassifying plaque ulcers as ihis by keeping in mind that ulcers ( rather than ihis associated with intraplaque hemorrhage ) typically demonstrate focal outpouching of flow - related enhancement with a narrow neck into a region of atherosclerotic plaque .
ihis assessments were made blinded to clinical data and brain mri data by a board - certified neuroradiologist .
reproducibility of these plaque assessments was made by a second independent radiologist who reviewed all mra studies blinded to clinical data , the brain mri findings , and the primary reader s interpretations .
since our acquisition also involves a larger field - of - view 2d - tof acquisition ( matrix size 320192 on 3 t , 256160 on 1.5 t , 22-cm field - of - view , slice thickness 1.6 mm , pixel size 0.8 mm ) from the aortic arch to the skull base , these images were used for determination of the distal internal carotid artery as the denominator for north american symptomatic carotid endarterectomy trial ( nascet ) stenosis .
we calculated nascet vessel narrowing by measuring the smallest luminal diameter relative to the caliber of normal - appearing distal internal carotid artery on axial source images .
we also used the 3d maximum intensity projection images to corroborate whether the stenosis measurements derived from axial images were consistent with the overall impression of luminal narrowing severity provided by the interpretation of the maximum intensity projection images .
given the known relative imprecision of tof imaging compared to contrast - enhanced techniques or catheter angiography in assessing stenosis severity , we dichotomized our stenosis severities into the more general 0% to 29% and 30% to 49% categories .
our primary question was whether , in patients with ischemic stroke of undetermined source , there was a higher prevalence of ihis ipsilateral to the infarct compared to the contralateral side . to compare the presence of ihis on the ipsilateral versus contralateral side within individual patients
, we used mcnemar s test for correlated proportions . because we studied patients with unilateral anterior circulation infarction , this approach allowed us to use each subject
s contralateral carotid artery as an internal control , thereby minimizing the impact of individual - level confounding bias since systemic vascular risk factors would presumably influence the cerebral hemispheres equally and differences due to unilateral abnormal carotid plaque could still be detected .
comparison of clinical characteristics between individual ihis - positive and ihis - negative patients was performed using either fisher exact test or the wilcoxon - mann whitney test as appropriate .
interobserver variability in ihis assessment was performed using both inter - rater agreement percentage and a cohen statistic .
to see whether ihis is suboptimally detected on lower magnetic field strength mri , a post - hoc sensitivity analysis limited to test data from 1.5 t mri was performed .
all analyses were performed using sas v9.3 ( sas institute , cary , nc ) .
subjects for this study were identified from an institutional review board approved clinical registry of all ischemic strokes at the new york - presbyterian hospital / weill cornell medical center , a tertiary - care hospital and certified primary stroke center .
all patients admitted to our hospital s stroke service with ischemic stroke during 2013 were prospectively included in a database that is part of the aha s get with the guidelines stroke national registry.9 the get with the guidelines data collection was performed using a standardized template to collect clinical data on consecutively admitted stroke patients.9 ischemic stroke was determined by inpatient vascular neurologists using the aha s definition10 of an episode of neurologic dysfunction caused by focal brain ischemia , based on either imaging evidence of infarction in a defined vascular distribution or clinical symptoms persisting > 24 hours .
trained hospital personnel collected information about the national institutes of health stroke scale upon presentation , prior stroke history , inpatient hospital diagnostic studies performed , and demographic characteristics .
in addition , the presence of the following vascular risk factors was also recorded : active tobacco use , diabetes ( defined as a hemoglobin a1c of > 6.5% or on diabetes medication ) , insulin use , hypertension ( blood pressure > 140/90 mm hg or on antihypertensive medication ) , atrial fibrillation , dyslipidemia ( low - density lipoprotein > 100 mg / dl or on statin therapy ) , coronary heart disease , and cardiac valvular disease . for subjects included in this prospective registry , 2 vascular neurologists , using all available medical data , independently assigned stroke etiology using the toast classification scheme.11 disagreements in subjects stroke subtype classification were adjudicated by a third vascular neurologist .
once this cohort of ischemic stroke patients was identified , the following additional inclusion criteria were applied : ( 1 ) ischemic stroke of undetermined source per the toast classification , ( 2 ) mri of the brain and mra of the neck ( including 3d and 2d tof sequences ) performed during the inpatient admission , and ( 3 ) mri evidence of diffusion - weighted imaging ( dwi)positive , unilateral anterior circulation infarct(s ) .
we also applied the following exclusion criteria : ( 1 ) bilateral or posterior circulation acute , dwi positive infarcts on mri ; and ( 2 ) evidence of carotid artery stenosis > 50% on sonography , computed tomography angiography , or mra as per north american symptomatic carotid endarterectomy trial criteria.1 in a sensitivity analysis , we additionally excluded patients who were classified as having a stroke of undetermined source because of the presence of 2 or more potential stroke causes , thereby focusing on patients with truly cryptogenic stroke .
all neck mra studies were performed on either 1.5 or 3.0 t signa ( general electric ) scanners using standard quadrature neck array coils . of note ,
neither high - resolution surface carotid coils nor gadolinium were used for these examinations , which were performed during the acute stroke workup .
the 3-minute 3d - tof acquisition involved a 20-cm field - of - view centered at the carotid artery bifurcation and included a 1.4-mm slice thickness and matrix of 320192 and 320224 on 1.5 and 3 t , respectively , yielding pixel sizes of 0.6 mm . because we aimed to assess the generalizability of this technique to routine clinical practice , no studies were excluded for patient motion artifact , and all studies with image quality sufficient to generate a clinical interpretation at the time of original image acquisition were included in our analysis .
dwi - positive lesions were also categorized in terms of whether the cerebral cortex was involved .
intraplaque high - intensity signal ( ihis ) on axial 3d - tof images was used as a presumed marker for intraplaque hemorrhage.12,13 we used a previously published method12,1416 in which hyperintense signal intensity in carotid plaque is assessed using region - of - interest analysis compared to background sternocleidomastoid muscle signal intensity . in those patients with visible nonhemodynamically stenosing plaque on tof images , we used a quantitative cutoff of signal intensity 50% greater than skeletal muscle based on region - of - interest analysis in the area of suspected ihis.1416 we took care to clearly delineate ihis from perivascular fat outside of the vessel by classifying a case as ihis - positive only when high signal occurred specifically at the site of a presumed atherosclerotic plaque , which we required to be detectable as a region of focal eccentric luminal narrowing seen on contiguous axial images .
such an effort minimized the chance that high - signal fat outside of the vessel would be mistaken for the intraplaque hemorrhage for which ihis is a surrogate.14 furthermore , we made an effort to avoid misclassifying plaque ulcers as ihis by keeping in mind that ulcers ( rather than ihis associated with intraplaque hemorrhage ) typically demonstrate focal outpouching of flow - related enhancement with a narrow neck into a region of atherosclerotic plaque .
ihis assessments were made blinded to clinical data and brain mri data by a board - certified neuroradiologist .
reproducibility of these plaque assessments was made by a second independent radiologist who reviewed all mra studies blinded to clinical data , the brain mri findings , and the primary reader s interpretations .
since our acquisition also involves a larger field - of - view 2d - tof acquisition ( matrix size 320192 on 3 t , 256160 on 1.5 t , 22-cm field - of - view , slice thickness 1.6 mm , pixel size 0.8 mm ) from the aortic arch to the skull base , these images were used for determination of the distal internal carotid artery as the denominator for north american symptomatic carotid endarterectomy trial ( nascet ) stenosis .
we calculated nascet vessel narrowing by measuring the smallest luminal diameter relative to the caliber of normal - appearing distal internal carotid artery on axial source images .
we also used the 3d maximum intensity projection images to corroborate whether the stenosis measurements derived from axial images were consistent with the overall impression of luminal narrowing severity provided by the interpretation of the maximum intensity projection images . given the known relative imprecision of tof imaging compared to contrast - enhanced techniques or catheter angiography in assessing stenosis severity , we dichotomized our stenosis severities into the more general 0% to 29% and 30% to 49% categories .
our primary question was whether , in patients with ischemic stroke of undetermined source , there was a higher prevalence of ihis ipsilateral to the infarct compared to the contralateral side . to compare the presence of ihis on the ipsilateral versus contralateral side within individual patients
, we used mcnemar s test for correlated proportions . because we studied patients with unilateral anterior circulation infarction , this approach allowed us to use each subject
s contralateral carotid artery as an internal control , thereby minimizing the impact of individual - level confounding bias since systemic vascular risk factors would presumably influence the cerebral hemispheres equally and differences due to unilateral abnormal carotid plaque could still be detected .
comparison of clinical characteristics between individual ihis - positive and ihis - negative patients was performed using either fisher exact test or the wilcoxon - mann whitney test as appropriate .
interobserver variability in ihis assessment was performed using both inter - rater agreement percentage and a cohen statistic . to see whether ihis is suboptimally detected on lower magnetic field strength mri , a post - hoc sensitivity analysis limited to test data from 1.5 t mri was performed .
all analyses were performed using sas v9.3 ( sas institute , cary , nc ) .
among 337 ischemic strokes in our institution s 2013 get with the guidelines stroke registry , 119 subjects ( 35.3% ) were classified as having stroke of undetermined source . after applying our additional inclusion and exclusion criteria , a total of 54 unique internal carotid arteries in 27 subjects ( 48.2% female , mean age 71.014.7 years ) formed the sample that was analyzed in this study ( table1 ) .
cohort baseline characteristics stratified by the presence of intraplaque high - signal intensity in the ipsilateral internal carotid artery on mr angiography of the neck p value by fisher exact test or wilcoxon - mann whitney as appropriate .
iqr indicates interquartile range ; iv tpa , intravenous tissue plasminogen activator ; mr , magnetic resonance ; nih , national institutes of health . all brain and mra neck images of this cohort were included for analysis , with no studies excluded for technical reasons .
the median interval days between the mri brain showing dwi - positive lesions and the mra neck was 0 , with a mean of 1.7 days , as most patients had mri of the brain performed concurrently during the same testing session as the neck mra .
similarly , the median interval days between stroke onset and neck mra was 1 , with a mean of 2.6 days .
a total of 21 of 27 subjects ( 77.8% ) had mri performed on a 1.5 t machine , with the remainder scanned on a 3 t machine .
the mean nascet degree of vessel narrowing was not significantly different between carotid arteries ipsilateral and contralateral to the side of stroke ( 10.5%sd 16.3% ipsilateral to the side of stroke versus 8.6%sd 15.9% contralateral to the side of stroke ; p=0.52 ) .
a total of 6 of 27 patients ( 22.2% ) had nonhemodynamically stenosing carotid plaque positive for ihis
ipsilateral to the dwi - positive lesion compared to 0 of 27 patients with ihis - positive plaques contralateral to the side of the infarction ( p=0.01 ) .
interobserver reproducibility of ihis assessment was excellent , with an inter - rater agreement of 98% , and a coefficient of 0.90 ( 95% ci : 0.70 to 1.00 ) ( representative neck and brain images are shown in figure 1 ) .
all 6 patients with ihis - positive plaques had dwi - positive lesions involving the ipsilateral cerebral cortex , compared to 12 of the 21 patients ( 57.1% ) without evidence of ihis - positive plaque ( p=0.07 ) .
patients with ihis - positive plaques were on average older than the cohort with ihis - negative plaques ( table1 ) .
stroke severity measures , completeness of diagnostic evaluations , type of diagnostic evaluation , the prevalence of vascular risk factors , and the degree of ipsilateral and contralateral carotid stenosis did not differ between the ihis - positive and ihis - negative groups ( table2 ) .
diagnostic stroke workups stratified by the presence of intraplaque high - signal intensity in the ipsilateral internal carotid artery on mra of the neck p value by fisher exact test .
cta indicates computed tomography angiography ; mra , magnetic resonance angiography ; tee , transesophageal echocardiogram ; tte , transthoracic echocardiogram . a , axial 3d - time - of - flight source image demonstrates signal hyperintensity in the plaque ( arrow ) of a nonstenosing left - sided carotid artery plaque .
the patent lumen ( arrowhead ) is clearly discriminated from the extraluminal high - intensity plaque on this and adjacent contiguous axial images .
b , axial diffusion - weighted imaging image shows evidence of high left - sided frontal and parietal acute infarctions in the same patient , including involvement of the cerebral cortex . in a sensitivity analysis excluding 2 subjects who had atrial fibrillation and therefore 2 or more potential causes of stroke , the prevalence of ihis - positive plaque ipsilateral to stroke remained significantly higher than the prevalence contralateral to the side of stroke ( p=0.02 ) .
similarly , in a sensitivity analysis excluding the 6 cases performed on the 3 t magnet , the prevalence of ihis - positive plaque ipsilateral to stroke remained significantly higher than in ihis - negative plaque ( p=0.03 ) .
among 337 ischemic strokes in our institution s 2013 get with the guidelines stroke registry , 119 subjects ( 35.3% ) were classified as having stroke of undetermined source . after applying our additional inclusion and exclusion criteria , a total of 54 unique internal carotid arteries in 27 subjects ( 48.2% female , mean age 71.014.7 years ) formed the sample that was analyzed in this study ( table1 ) .
cohort baseline characteristics stratified by the presence of intraplaque high - signal intensity in the ipsilateral internal carotid artery on mr angiography of the neck p value by fisher exact test or wilcoxon - mann whitney as appropriate .
iqr indicates interquartile range ; iv tpa , intravenous tissue plasminogen activator ; mr , magnetic resonance ; nih , national institutes of health .
all brain and mra neck images of this cohort were included for analysis , with no studies excluded for technical reasons .
the median interval days between the mri brain showing dwi - positive lesions and the mra neck was 0 , with a mean of 1.7 days , as most patients had mri of the brain performed concurrently during the same testing session as the neck mra .
similarly , the median interval days between stroke onset and neck mra was 1 , with a mean of 2.6 days .
a total of 21 of 27 subjects ( 77.8% ) had mri performed on a 1.5 t machine , with the remainder scanned on a 3 t machine .
the mean nascet degree of vessel narrowing was not significantly different between carotid arteries ipsilateral and contralateral to the side of stroke ( 10.5%sd 16.3% ipsilateral to the side of stroke versus 8.6%sd 15.9% contralateral to the side of stroke ; p=0.52 ) .
a total of 6 of 27 patients ( 22.2% ) had nonhemodynamically stenosing carotid plaque positive for ihis ipsilateral to the dwi - positive lesion compared to 0 of 27 patients with ihis - positive plaques contralateral to the side of the infarction ( p=0.01 ) .
interobserver reproducibility of ihis assessment was excellent , with an inter - rater agreement of 98% , and a coefficient of 0.90 ( 95% ci : 0.70 to 1.00 ) ( representative neck and brain images are shown in figure 1 ) .
all 6 patients with ihis - positive plaques had dwi - positive lesions involving the ipsilateral cerebral cortex , compared to 12 of the 21 patients ( 57.1% ) without evidence of ihis - positive plaque ( p=0.07 ) .
patients with ihis - positive plaques were on average older than the cohort with ihis - negative plaques ( table1 ) .
stroke severity measures , completeness of diagnostic evaluations , type of diagnostic evaluation , the prevalence of vascular risk factors , and the degree of ipsilateral and contralateral carotid stenosis did not differ between the ihis - positive and ihis - negative groups ( table2 ) .
diagnostic stroke workups stratified by the presence of intraplaque high - signal intensity in the ipsilateral internal carotid artery on mra of the neck p value by fisher exact test .
cta indicates computed tomography angiography ; mra , magnetic resonance angiography ; tee , transesophageal echocardiogram ; tte , transthoracic echocardiogram . a , axial 3d - time - of - flight source image demonstrates signal hyperintensity in the plaque ( arrow ) of a nonstenosing left - sided carotid artery plaque .
the patent lumen ( arrowhead ) is clearly discriminated from the extraluminal high - intensity plaque on this and adjacent contiguous axial images .
b , axial diffusion - weighted imaging image shows evidence of high left - sided frontal and parietal acute infarctions in the same patient , including involvement of the cerebral cortex . in a sensitivity analysis excluding 2 subjects who had atrial fibrillation and therefore 2 or more potential causes of stroke , the prevalence of ihis - positive plaque ipsilateral to stroke remained significantly higher than the prevalence contralateral to the side of stroke ( p=0.02 ) .
similarly , in a sensitivity analysis excluding the 6 cases performed on the 3 t magnet , the prevalence of ihis - positive plaque ipsilateral to stroke remained significantly higher than in ihis - negative plaque ( p=0.03 ) .
using data from a prospective inpatient ischemic stroke registry , we found that a mra - defined plaque risk marker in nonhemodynamically stenosing carotid artery plaque ( ihis ) was significantly more prevalent ipsilateral to the side of cryptogenic stroke compared to the side contralateral to the stroke . those patients with and without plaque ihis were not significantly different in terms of stroke severity , stroke diagnostic workups , or vascular risk factors
however , patients with plaque ihis were older than those without ihis , consistent with population - based epidemiologic data suggesting that complex atherosclerotic plaque elements increase in prevalence with age.17,18 additionally , the nascet degree of luminal narrowing was not significantly different between the ipsilateral and contralateral sides . taken together , our data suggest that a subset of cryptogenic strokes may be caused by vulnerable carotid artery plaque in patients with plaque burden considered to be insignificant based on traditional luminal stenosis severity measures .
in other words , embolization from large - artery atherosclerosis may occur even in the absence of hemodynamically significant internal carotid artery stenosis .
our data suggest that vulnerable carotid plaques likely cause some proportion of cryptogenic strokes , because current classification of stroke subtypes requires luminal stenosis of at least 50% in order to classify a stroke as being caused by large - artery atherosclerosis . our study s results are consistent with a prior report of carotid artery plaque composition specifically in cryptogenic stroke . in this
study,8 investigators used a gadolinium - enhanced , multisequence protocol with a dedicated carotid coil and found that the presence of aha type vi plaque in nonstenosing carotid artery plaque was significantly more prevalent on the side ipsilateral to the infarct in patients with cryptogenic stroke .
it is interesting to note that when the 60 strokes of undetermined source in both studies are considered together , neither we nor freilinger et al found a single case in which complicated nonhemodynamically stenosing carotid plaque was found contralateral to the side of cryptogenic stroke . despite the consistency of our main findings ,
it is important to note that the freilinger et al study evaluated features such as fibrous plaque rupture and luminal thrombus in addition to intraplaque hemorrhage .
though our plaque imaging technique may provide less detailed plaque characterization , there are several reasons why our approach might be more practical to implement in acute stroke patients : ( 1 ) our methodology does not require specialized mri hardware ( a carotid coil ) and therefore can occur as part of the routine initial acute stroke workup rather than at a separate dedicated carotid plaque imaging session after stroke diagnosis is confirmed ; ( 2 ) our assessment of ihis can occur without the necessity of gadolinium injection and takes 3 minutes compared to 18 minutes in the freilinger et al multisequence protocol ; ( 3 ) our risk marker is rapidly detectable on imaging ( either present or absent ) and does not require the more time - consuming assessment of multiple plaque tissue types ; and ( 4 ) our method can be performed in all mra studies , without any exclusions related to motion or other technically suboptimal studies , which are unavoidable in the imaging of acute stroke patients and can limit interpretability of multisequence high - resolution plaque imaging . given that many patients with known or suspected stroke are imaged at the time of presentation to the emergency department or other acute care setting , our study is particularly informative as it demonstrates that a simple mra neck sequence historically used to assess for luminal stenosis also contains plaque risk information .
moreover , our plaque classification system ( ihis present or not ) is highly reproducible with an inter - rater agreement of 98% and of 0.90 ( 95% ci , 0.70 to 1.00 ) . our interobserver reproducibility was higher in the current study compared to previous similar work in patients with high - grade carotid stenosis.14 one possible reason for this difference in reproducibility is that there may be a lower prevalence of other advanced atherosclerotic features in 0% to 49% stenosis plaque compared with higher - grade stenosis , thereby potentially simplifying image analysis and reducing the risk of the false - positive assessments more likely to occur in the presence of ulceration , lipid , and other complicated plaque features .
similarly , an added benefit of this approach is that such a system does not require the more detailed plaque element assessment necessary in aha plaque subtype classification for which fibrous cap rupture , intraplaque hemorrhage , or juxtaluminal hemorrhage / mural thrombus must be characterized.19 our findings have face validity because extracting plaque information from 3d - tof mra source images has been shown in prior studies to be potentially useful in providing plaque risk stratification in patients with more substantial plaque burden.14 for example , in patients with high - grade proximal internal carotid artery stenosis , those with ihis on routine mra source images were 14 times more likely to have had symptomatic disease compared to those with high - grade stenosis and no ihis.14 the dominant plaque element present in areas of ihis on mra images is most likely intraplaque hemorrhage , as several prior studies have shown a high correlation between high signal on mra source images and intraplaque hemorrhage on histopathologic analysis.5,12,13 such intramural hemorrhage likely induces a prothrombotic environment that may promote embolism formation.20 the detection of intraplaque hemorrhage on mri is possible with a wide range of techniques .
the use of a dedicated carotid coil with a multisequence mri test is one such approach , which has the advantages of excellent spatial resolution and a high signal - to - noise ratio.5,13 the disadvantages of this method include the need for specialized equipment and extra time required for imaging and interpretation .
an alternative strategy , which we used in our study , is based on the principle that intraplaque hemorrhage demonstrates hyperintensity greater than background skeletal muscle on t1-weighted images or images dependent on a tissue s t1 characteristics , such as tof imaging.15,16,21 using this principle , some studies have utilized a large field - of - view coronal gradient echo t1-weighted acquisition such as a 3d - magnetization prepared rapid acquisition gradient - echo sequences , which can allow for black blood imaging and can therefore provide increased conspicuity of plaque hemorrhage adjacent to the carotid lumen .
such an approach requires an extra 5 minutes of imaging time in addition to the sequences typically performed to characterize luminal stenosis . in our study , we extracted ihis data ( a surrogate for intraplaque hemorrhage ) using 3d - tof images alone and therefore used only imaging data that are commonly obtained at stroke care facilities that use extracranial mra to evaluate acute stroke patients .
the general benefit of this simpler approach is that plaque hemorrhage can be detected rapidly using larger field - of - view imaging without specialized equipment .
furthermore , studies have shown that such rapid techniques of plaque hemorrhage detection can predict future ischemic events with the same predictive strength as hemorrhage detected via the more detailed , carotid - coil - dependent techniques.5,6 disadvantages of these simpler techniques , especially those without dedicated fat - suppression , is that the resulting decreased tissue discrimination and spatial resolution can make it more challenging to distinguish plaque hemorrhage from other high - risk plaque elements , perivascular fat , or small plaque ulcers . since our simplified plaque characterization technique lacks the specificity of a multisequence approach with dedicated mri hardware , it possible that ihis may represent lipid - rich necrotic core , another component of complicated carotid atherosclerotic plaque that can demonstrate t1 shortening.20 however , differentiating between intraplaque hemorrhage and lipid - rich necrotic core via carotid plaque imaging may not be clinically significant .
for example , a recent meta - analysis showed that the presence of intraplaque hemorrhage or lipid - rich necrotic core as determined by carotid plaque mri conferred similar future risk of ipsilateral stroke ( 3- to 5-fold increased risk ) in patients with carotid stenosis.5 future studies may be helpful to assess whether multisequence carotid - coil - dependent plaque imaging adds additional information over standard mra techniques that are more practical to perform in an acute stroke evaluation .
first , although our clinical data collection was prospective , our classification of toast stroke subtypes was made retrospectively .
we attempted to minimize misclassification by relying on a team adjudication process by 3 vascular neurologists .
additionally , reviewing records after hospital discharge allowed for an assessment of toast subtype using more complete diagnostic evaluations , which continued into the outpatient setting .
second , in a small ( n=2 ) subset of patients , more than 1 plausible cause of stroke was present , thereby limiting our ability to infer that stroke had occurred directly as a consequence of nonhemodynamically stenosing carotid plaque .
third , the mra neck studies that demonstrated complicated carotid plaque were performed after the index stroke and were read retrospectively by a blinded neuroradiologist .
however , nearly all of our mra neck studies occurred on the day of the acute infarction , and it is unlikely that plaque characteristics changed significantly in such a short interval of time , especially in light of epidemiologic data showing that in most patients , carotid plaque morphology does not significantly change over a 1-year period.22 fourth , though we attempted to minimize the mischaracterization of perivascular fat and plaque ulcers as ihis , further studies using black blood mra techniques , which do not require a carotid coil , would be informative to assess whether alternative mra techniques will yield similar results to our study and the freilinger et al studies .
finally , our study has a small absolute sample size for which a formal power calculation was not performed in advance . despite this , it is unlikely that the association between ihis - positive plaques and cryptogenic stroke was due to chance ( p=0.01 ) .
it is important to note that plaque hemorrhage is present in asymptomatic subjects , and that as a result , the association between ihis - positive carotid plaque and ipsilateral infarcts does not prove that an ihis - positive carotid plaque in a given patient is necessarily the cause of that patient s stroke .
future , appropriately powered prospective studies are now warranted to confirm our results and also to study the issue of stroke recurrence in this patient group . furthermore , future research is necessary to assess whether careful patient selection using evaluation for high - risk carotid plaques would impart benefit to revascularization procedures in patients who are traditionally medically managed based on degree of luminal stenosis.23
we have demonstrated that a simple , commonly performed , 3-minute mra neck 3d - tof imaging test can detect the presence of complicated but nonhemodynamically stenosing atherosclerotic plaque , which may explain the mechanism of some strokes currently classified as cryptogenic .
our results suggest that the routine assessment of plaque vulnerability is possible using existing acute stroke mri protocols and that such information might prospectively improve our ability to classify stroke etiology at the time of patient presentation .
dr gupta s effort was supported by an association of university radiologists - general electric radiology research award fellowship and the foundation of the american society of neuroradiology scholar award .
dr kamel s effort was supported by grant k23ns082367 from the national institute of neurological disorders and stroke .
the authors report no disclosures pertaining to the work under consideration . outside this work , dr kamel reports serving as a lecturer for genentech on the subject of alteplase for acute ischemic stroke .
Output:
| backgroundmagnetic resonance imaging of carotid plaque can aid in stroke risk stratification in patients with carotid stenosis .
however , the prevalence of complicated carotid plaque in patients with cryptogenic stroke is uncertain , especially as assessed by plaque imaging techniques routinely included in acute stroke magnetic resonance imaging protocols .
we assessed whether the magnetic resonance angiography
defined presence of intraplaque high - intensity signal ( ihis ) , a marker of intraplaque hemorrhage , is associated with ipsilateral cryptogenic stroke.methods and resultscryptogenic stroke patients with magnetic resonance imaging evidence of unilateral anterior circulation infarction and without hemodynamically significant ( 50% ) stenosis of the cervical carotid artery were identified from a prospective stroke registry at a tertiary - care hospital .
high - risk plaque was assessed by evaluating for ihis on routine magnetic resonance angiography source images using a validated technique . to compare the presence of ihis on the ipsilateral versus contralateral side within individual patients
, we used mcnemar s test for correlated proportions .
a total of 54 carotid arteries in 27 unique patients were included .
a total of 6 patients ( 22.2% ) had ihis - positive nonstenosing carotid plaque ipsilateral to the side of ischemic stroke compared to 0 patients who had ihis - positive carotid plaques contralateral to the side of stroke ( p=0.01 ) .
stroke severity measures , diagnostic evaluations , and prevalence of vascular risk factors were not different between the ihis - positive and ihis - negative groups.conclusionsour findings suggest that a proportion of strokes classified as cryptogenic may be mechanistically related to complicated , nonhemodynamically significant cervical carotid artery plaque that can easily be detected by routine magnetic resonance imaging / magnetic resonance angiography acute stroke protocols . |
PubmedSumm6563 | ***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: schizophrenia ( sz ) is a debilitating illness characterized by delusions , hallucinations and disorganized thought .
impairments of cognitive functions , such as working memory , are also considered core features of the disorder ( green , 2006 ; kahn and keefe , 2013 ; park and gooding , 2014 ) and have been linked to genetic liability ( agnew - blais and seidman , 2013 ; reichenberg and harvey , 2007 ) .
however , little is known about how cognitive dysfunction is related to underlying brain anatomy and brain function , and improving our understanding of these associations may help uncover the neuronal substrates of the disease ( kahn and keefe , 2013 ; schultz et al . , 2012a ) .
neuroimaging studies have identified brain regions and networks involved in cognitive processing ( alnaes et al .
, 2015 ; cabeza and nyberg , 2000 ; cole et al . , 2014 ) , and both hypo- and hyperactivation ( brandt et al . , 2014 ; glahn et al . , 2005 ; kraguljac et al . , 2013 ;
ragland et al . , 2007 ) , as well as brain network dysconnectivity ( brandt et al .
, 2015 ; fornito et al . , 2012b ; kaufmann et al . , 2015 ; pettersson - yeo et al . ,
, fmri studies have demonstrated abnormal neuronal recruitment during working memory processing ( anticevic et al . , 2013 ;
callicott et al . , 2003 ; glahn et al . , 2005 ; henseler et al .
, 2009 ; karlsgodt et al . , 2007 ; kim et al . , 2010 ; potkin et al .
2011 ) reflecting dysfunction of a fronto - parietal network including the lateral prefrontal cortex and posterior parietal cortex , as well as anterior cingulate and other regions related to execution of challenging cognitive tasks ( owen et al . , 2005 ) .
this network shows increased activation during cognitive processing and is thought to reflect focus on task - relevant information , like updating information in working memory .
similar networks have been referred to as central executive ( bressler and menon , 2010 ; sridharan et al . , 2008 ) , executive control ( seeley et al . , 2007 ) , and task - positive ( fox et al . , 2005 ) networks .
the function of such a task - positive fronto - parietal network and its interactions with a task - negative default - mode network ( dmn ) are considered to play important roles in cognition ( cocchi et al . , 2013 ;
the dmn shows task - related deactivation and has been hypothesized to reflect the suppression of task - irrelevant internal activity to optimize goal - directed cognition ( anticevic et al . , 2012 ) .
cognitive impairments in sz may not only be associated with the failure to recruit the fronto - parietal network , but also a relative lack of dmn deactivation ( whitfield - gabrieli and ford , 2012 ) . in line with this
, a failure of dmn deactivation may reflect a key feature of sz ( broyd et al .
, 2009 ; landin - romero et al . , 2015 ; pomarol - clotet et al . ,
2008 ) , and the reciprocity between these two networks may be affected in patients ( anticevic et al . , 2013 ;
nygard et al . , 2012 ; whitfield - gabrieli et al . , 2009 ) .
structural brain abnormalities have been consistently reported in patients with sz , including reductions in cortical thickness , surface area , gray matter volumes , and gyrification ( ellison - wright and bullmore , 2010 ; gupta et al . , 2015 ; nesvag et al . , 2014 ; rimol et al . , 2010 ; rimol et al . ,
2012 ) , global and subcortical volumes ( van erp et al . , 2015 ) , as well as white matter microstructure as measured by diffusion tensor imaging ( dti ) ( ellison - wright and bullmore , 2009 ) .
gray matter reductions have been identified in widespread brain regions , but are particularly pronounced in fronto - temporal regions ( glahn et al . , 2008 ; gupta et al . , 2015 ; nesvag et al .
2010 ) , including the insula ( glahn et al . , 2008 ; shepherd et al . ,
it has been suggested that these structural brain alterations are associated with abnormal integration of information between frontal and temporal cortical areas ( friston and frith , 1995 ; schultz et al . , 2012b ) .
similarly , functional neuroimaging studies have reported disrupted fronto - temporal connectivity in sz related to cognitive processing including working memory ( cocchi et al .
, 2014 ; crossley et al . , 2009 ; meyer - lindenberg et al . , 2001 ; wolf et al . , 2007 ) , indicating that cognitive impairment is a result of underlying brain dysconnectivity . in order to understand more of the relationship between structural and functional brain abnormalities in sz
, several studies have examined associations between structural mri and neuropsychological performance ( ehrlich et al . , 2012 ;
, 2010 ; hartberg et al . , 2010 ) , or between brain structure and brain activation during cognitive tasks using different methods and modalities ( see schultz et al .
a common finding has been significant structure function associations in patients , but not in healthy controls ( fusar - poli et al .
previous studies have however often performed separate analyses of brain structure and function without correlating them directly ( pomarol - clotet et al .
, while only a few have combined structural and functional measures in the same analysis allowing for interpretation of joint features across modalities ( calhoun et al . , 2006
further , a common approach has been to use structural and functional regions of interest ( harms et al .
, 2013 ; pujol et al . , 2013 ; schultz et al . , 2012b ) , thus restricting the anatomical interpretations to these regions .
the sample size has often been small , comprising around 15 patients and 15 controls ( calhoun et al . , 2006 ; fusar - poli et al . , 2011a ; pujol et al . , 2013 ; rasser et al . ,
thus , there is a need for studies combining structural and functional modalities in the same analysis in large samples of patients and controls .
lastly , despite the relevance of task - positive and task - negative networks in cognition and sz , only one regions - of - interest based study comprising a small number of patients has investigated the relationship between these functional brain systems and brain anatomy in sz ( pujol et al . , 2013 ) .
summarized , functional and structural imaging has documented a plethora of brain abnormalities in sz . however , more knowledge is needed to map task - related brain activation onto underlying brain structure in sz and hc , and to assess if patients show differential structure function relationships compared to hc .
these are important questions pertaining to the fundamental aim of delineating associations between structural and functional properties of the brain , and for increasing the understanding of the mechanisms of severe mental illness , such as sz .
thus , the main aim of the current study was to determine structure function relationships in a large sample of sz ( n = 96 ) and hc ( n = 142 ) by combining patterns of fmri activation during a working - memory paradigm ( n - back ) and key brain morphometric properties including vertex- and voxel - based measures of surface area , cortical thickness , and gray matter volume .
we used linked independent component analysis ( lica ) , a data - driven approach in which several imaging modalities may be combined ( groves et al .
, 2011 ; groves et al . , 2012 ) , and tested for associations between lica components reflecting brain structural features and functional brain networks related to task - positive and task - negative activation , respectively , and to what degree these associations were different in sz compared to hc .
based on the few previous studies examining associations between task - related fmri activation and gray matter structure in sz ( calhoun et al . , 2006 ; fusar - poli et al .
2012b ) , we hypothesized that strong task - related activation and deactivation would be associated with brain patterns reflecting increased structural integrity , including cortical thickness and gray matter volume in overlapping brain regions .
further , we expected that any group differences in the structure function relationships would reflect disruptions of fronto - parietal , default - mode , and fronto - temporal brain regions in sz .
lastly , likely related to larger between - subject variance , we expected stronger structure function associations in sz compared to hc .
( 2014 , 2015 ) , were recruited as part of the thematically organized psychosis ( top ) study , comprising 96 dsm - iv - diagnosed patients with schizophrenia spectrum disorders ( 70 schizophrenia , 15 schizoaffective disorder , 11 schizophreniform disorder ) , referred to as sz , and 142 healthy controls ( hc ) .
healthy controls were randomly selected from the same catchment area as the patient group using statistical records .
28% replied to the invitation and consented to participate , and of these 37.4% participated in the mr scanning .
the study is approved by the regional committee for medical research ethics and the norwegian data inspectorate . written informed consent was obtained from all participants according to the declaration of helsinki .
exclusion criteria were presence of a developmental disorder or serious brain damage , and having metal implants , cardiac pacemaker or other mri contraindications .
healthy controls were screened with a questionnaire about severe mental illness and the primary care evaluation of mental disorders ( spitzer et al . , 1994 ) , and were excluded if they or a first - degree relative had a lifetime history of sz , bipolar disorder or major depression .
patients were characterized through a clinical interview conducted by trained physicians or clinical psychologists , covering diagnostics , symptoms , cognition , drug use and medication status .
diagnosis was established using the structured clinical interview for dsm - iv axis i disorders ( scid ) ( first et al . , 1995 ) .
diagnostic reliability was satisfactory , with overall agreement for dsm - iv diagnosis categories of 82% and overall kappa = 0.77 ( 95% ci : 0.600.94 ) .
current symptoms were assessed on the day of scanning using a brief interview covering psychosis , depression , and elevated mood in the previous week ( aminoff et al . , 2011 ) .
current psychotic symptoms were present in less than one third of the patients , indicating low symptom levels at the time of scanning .
regular medication was also recorded on the scanning day , as well as the use of alcohol and illicit drugs .
the experimental paradigm was an n - back task with consecutive presentations of pairs of numbers between 1 and 9 ( haatveit et al .
2004 ) . in a 0-back condition , participants were instructed to press a response button when the two numbers were identical . in a 2-back condition ,
the numbers in each stimulus pair were identical and participants were instructed to press a response button when they were the same as the ones presented two trials earlier .
stimuli were presented using a blocked design with four on - blocks and four off - blocks . on - blocks of 52 s duration comprised 18 stimuli presented in a pseudo - randomized sequence , including 34 targets ( in total 12 targets in 0-back and 13 targets in 2-back ) .
stimulus duration was 300 ms and the inter - stimulus interval was 2500 ms . on - blocks were followed by off - blocks consisting of a fixation cross of 26 s duration .
the paradigm was programmed in e - prime ( psychology software tools , inc . , sharpsburg , usa ) and stimuli were presented through goggles ( nordicneurolab inc . ,
mri data were acquired on a 1.5 t siemens magnetom sonata ( siemens medical solutions , erlangen , germany ) using a standard head coil at oslo university hospital .
structural data were acquired using a 3d t1-weighted magnetization prepared rapid acquisition gradient echo ( mprage ) sequence with the following parameters : tr / te / ti / fov / fa / matrix = 2730 ms/3.93 ms/1000 ms/240 mm/7/192 256 ; voxel size 1.33 0.94 1 mm , 160 sagittal slices .
functional imaging with 164 whole brain volumes per run was obtained with a t2 * -weighted echo - planar imaging ( epi ) pulse sequence with the following parameters : tr / te / fov / fa / matrix = 2040 ms/50 ms/224 224 mm/90/64 64 .
each volume consisted of 24 axial slices with a voxel size of 3 mm in the axial plane , and a slice thickness of 4 mm with 1 mm gap between slices .
the first seven volumes and the last volume were discarded , leaving 156 volumes for analysis .
an initial screening of the data was performed to exclude datasets with obvious movement or scanner artifacts . from the remaining available sample of 115 patients and 163 controls , 16 sz and 20 hc
were excluded due to task performance below chance level ( sz : n = 3 ) , excessive relative head motion ( displacement from 1 volume to the next ) defined as more than 3 sds above the mean ( sz : n = 6 , hc : n = 3 ) , and poor data quality ( structural images ; sz : n = 3 , hc : n = 1 ; signal loss in functional images ; sz : n = 7 , hc : n = 16 ) , yielding 96 sz and 142 hc in the included sample .
t1-weighted scans were processed using freesurfer ( http://surfer.nmr.mgh.harvard.edu ) including 3d surface reconstruction and full brain segmentation ( fischl et al . , 2002 ) .
the segmented volume was used in order to produce high quality brain masks for co - registration .
freesurfer was also used to estimate vertex - wise cortical thickness and surface area measures ( dale et al .
cortical thickness was obtained by reconstructing the gray / white matter boundary and the pial surface ( dale et al .
surface area was estimated by registering each subject 's reconstructed surfaces to a common template , and the relative amount of expansion or compression at each vertex was used as a proxy for regional arealization .
surface maps were resampled and mapped to a common coordinate system ( fsaverage5 , 10,242 vertices ) using a non - rigid high - dimensional spherical averaging method to align cortical folding patterns ( fischl et al . , 1999 ) .
fsl - vbm ( douaud et al . , 2007 ) , a voxel - based morphometry ( vbm ) analysis ( ashburner and friston , 2000 ; good et al . , 2001 ) , was used to derive a gray matter volume ( gmv ) map .
the registered map was divided by the jacobian map of the deformation field to account for local contraction and expansion .
fmri data were processed using feat , part of fmrib 's software library ( fsl ; http://www.fmrib.ox.ac.uk/fsl ) ( jenkinson et al . , 2012 ) .
preprocessing included motion correction ( jenkinson et al . , 2002 ) , non - brain removal ( smith , 2002 ) , spatial smoothing using a gaussian kernel of full width of half maximum ( fwhm ) = 6 mm , and high - pass temporal filtering with a 90 s window . registration from fmri to structural space
, 2002 ) , and fmri data were warped to mni space via the high - resolution structural volume using fnirt ( http://fsl.fmrib.ox.ac.uk/fsl/fslwiki/fnirt ) . in a lower - level general linear model ( glm )
analysis for each run ( 0-back and 2-back ) , the onset and duration of the on - blocks were modeled with the off - blocks as implicit baseline .
the design matrix was filtered and convolved with a hemodynamic response function ( hrf ) before the model fit .
motion ( translation and rotation ) parameters as estimated by the motion correction during preprocessing were included in the model to remove residual motion effects that were left after correction , and a temporal derivative was added to adjust for regional differences in the timing of the hrf .
this first - level analysis resulted in individual contrast parameter estimate ( cope ) maps reflecting the on vs. off contrast within 0-back and 2-back .
then , an intermediate - level fixed - effects analysis was performed to calculate individual copes reflecting the 2-back vs 0-back contrast .
cortical thickness maps were smoothed using a gaussian kernel with an fwhm of 15 mm , yielding an effective smoothness of 20.8 mm as estimated based on hagler et al .
( 2006 ) . to match the smoothness across measures , which may be beneficial in order to match the dimensionality across features , smoothing of the surface area , gmv , and cope maps
gmv and cope maps were resampled to have an isotropic voxel size of 4 mm using a trilinear interpolator , and subsequently smoothed using freesurfer 's tool mri_fwhm with an fwhm of 10.5 and 9.8 mm , respectively . whereas the main analysis was performed using matched smoothness across modalities , the necessity and utility of assuming a common smoothing level across modalities in a lica context is unresolved .
therefore , lica and the main between - subjects analyses were rerun with no additional smoothing of the cope maps and less smoothing of gmv maps ( using the same fwhm value of 9.4 mm as described by groves et al .
the purpose was to assess the robustness of the results across smoothing levels , and specifically test whether significant findings from the main analysis were replicated in the additional analysis .
multimodal analysis was performed using lica ( groves et al . , 2011 , 2012 ) including three structural and three functional modalities : cortical surface area , thickness , and gmv , as well as full - brain and unthresholded individual
cope maps for 0-back ( task vs. rest ) , 2-back ( task vs. rest ) , and 2-back > 0-back .
dimensionality selection was automatically performed by lica ( groves et al . , 2011 ) , yielding 66 components ( 83 components for the additional analysis with less smoothing ) . in lica
, each component has a shared individual subject weight ( loading ) across modalities , indicating the degree to which each subject contributes to that component .
the spatial maps of all components were inspected , and the relative weight of each modality in each component was assessed .
no components showed substantial fusing between structural and functional modalities , i.e. more than 10% involvement of at least one structural and one functional modality .
27 components were defined as structural ( < 10% total involvement of functional modalities ) and 39 as functional ( < 10% total involvement of structural modalities ) . the structural components , including the modalities and brain regions involved , are summarized in table a.1 .
based on the spatial maps , two functional components were selected for correlation with these structural components : a task - positive fronto - parietal network ( fpn ; ic2 ) overlapping with a central executive network ( bressler and menon , 2010 ; sridharan et al . , 2008 ) , and a task - negative default - mode network ( dmn ; ic12 ) ( cole et al . , 2010 ; smith et al . ,
both components showed strong contributions from 2-back and 2-back > 0-back cope maps , and were chosen based on their spatial similarity with canonical task - positive and task - negative patterns of brain activation ( cocchi et al .
2010 ) , as well as the variance explained by these two components within the 2-back modality across subjects .
the spatial maps of the fpn and dmn lica components overlapped highly with brain regions showing positive and negative correlations with the task , respectively ( fig .
1 ) , which was confirmed by the correlations between the spatial maps of fpn / dmn components and 2-back cope - maps , as estimated using fslcc in fsl ( fpn vs. 2-back > rest : r = .76 ; dmn vs. rest > 2-back : r = .66 ) .
fpn explained 17.1% ( ranked first , i.e. being the component explaining the largest amount of variance ) and dmn explained 6.1% ( ranked fourth ) of the variance , i.e. together these components explained 23.2% of the total variance across the brain in the 2-back modality .
other functional components related to 2-back reflected brain networks such as left ( 6.3% ) and right ( 4.9% ) fronto - parietal , cingulo - opercular ( 4.3% ) , parietal ( dorsal attention : 3.9% ) , and occipital ( primary visual : 4.2% ; secondary visual : 3.6% ) networks .
n - back performance was assessed using d - prime ( d ) ( see haatveit et al . , 2010 ) and response time ( rt ) on correct responses .
repeated measure anovas were performed with load ( 0-back , 2-back ) as within - subject factor and diagnosis ( sz , hc ) as between - subject factor to test for main effects of load and diagnosis and their interactions on d and rt . in all analyses ,
the functional and structural components identified using lica were investigated by using the individual subject weights as input .
linear regressions were performed to investigate group differences within fpn and dmn while covarying for sex and age .
associations between the two functional components were assessed using partial correlations across groups ( covarying for sex , age , and diagnosis ) and within groups ( covarying for sex and age ) .
we tested for associations with task performance ( d and rt during 2-back ) and relative subject motion during 2-back on the two functional components while covarying for sex , age , and diagnosis .
the functional components showed no clear multi - modal fusion with structural modalities , and structure function relationships were assessed based on the correlations between the subject weights of the two functional components and the structural components . in order to investigate the associations between structure and function across groups ,
linear regressions were performed with each structural component as independent variable and each functional component as dependent variable , using two different models : ( 1 ) while covarying for sex , age , and diagnosis , and ( 2 ) while covarying for sex , age , diagnosis , and the interaction between structural component and diagnosis . for associations that did not show a significant interaction effect ,
the results are reported and interpreted from the across groups analysis without interaction term . for cases with a significant interaction effect ,
results are reported from the across groups analysis with interaction term , but the structure function association within each group is used for interpretation of the results . between groups ( case control )
differences in structure function associations were inferred from the interaction term ( structural component diagnosis ) from the same statistical model .
associations within groups are also reported ( covarying for sex and age ) . to assess the methodological generalizability of the findings
, we tested the associations between the two functional components and several conventional structural measures : ( 1 ) surface area ( vertex - based analysis using freesurfer ) , ( 2 ) cortical thickness ( vertex - based analysis using freesurfer ) , ( 3 ) gmv ( voxel - based analysis using fsl - vbm ) , and ( 4 ) selected global and regional brain volumes , including intracranial volume , total cortical volume , total subcortical gray matter volume , as well as bilateral volumes of the lateral ventricles , hippocampus , amygdala , thalamus , caudate , putamen , pallidum , corpus callosum , and cerebellar cortex . here , using linear regressions , we tested the effect of each functional component on surface area , thickness and gmv , while we tested the effect of each brain structural volume on the functional components , both across groups ( covarying for sex , age , and diagnosis ) and within groups ( covarying for sex and age ) .
for the associations with surface area and structural volumes , intracranial volume was also included as covariate . for structure
function associations surviving correction for multiple comparisons within patients , post - hoc tests were performed to examine the effects of possible confounders , including current symptoms ( psychosis , depression , elevated mood ) , lifetime symptoms ( depression , mania ) , medication level ( antipsychotics , antiepileptics , antidepressants , anxiolytics ) , duration of illness , and substance use ( alcohol use , illicit drug use , drug disorder , smoking ) .
each covariate was included sequentially in the within - group model in addition to sex and age . for associations surviving correction for multiple comparisons across and between groups , as well as within sz
, the analyses were also performed after excluding patients with schizoaffective ( n = 15 ) and schizophreniform ( n = 11 ) disorders .
further , effects of task performance ( d and rt during 2-back ) and relative subject motion during 2-back were tested by including these variables in the model . for the main analysis of structure
function associations across , between , and within groups , correction for multiple comparisons was performed using permutation testing ( nichols and holmes , 2002 ) .
the subject weights of each of the two functional components ( fpn , dmn ) were permuted together with the covariates ( sex , age , diagnosis ) 10,000 times with respect to the subject weights of the structural components . in each iteration ,
the maximum positive and minimum negative t statistics across the structural components were computed and stored , resulting in a two - tail null distribution of the t - statistics .
the corrected p - value was obtained by comparing the t - statistics obtained from the original analyses to the null distribution .
the main focus was on associations that were significant at a corrected p - level , but effects with a nominal p < .05 ( uncorrected ) are also reported for full transparency and in order to facilitate comparisons with previous and future studies . for other analyses ,
the statistical threshold was set to p < .05 ( uncorrected ) . all statistical analyses were carried out using ibm spss statistics version 22 and r ( http://www.r-project.org ) .
table 2 summarizes task performance . in line with previous reports from an overlapping sample ( brandt et al . , 2014 ;
brandt et al . , 2015 ) , significant group differences in d and rt were found in both load conditions , indicating reduced target discrimination and increased response times in sz . in addition to main effects of load and diagnosis on d ( load : f = 204.8 ; diagnosis : f = 37.4 ; p < .001 ) and rt ( load : f = 98.2 ; diagnosis : f = 12.6 ; p <
.001 ) , there was also a significant load diagnosis interaction on both measures ( d : f = 38.0 , p < .001 ; rt : f = 8.7 , p = .004 ) , indicating larger group differences during 2-back compared to 0-back .
1 shows spatial maps of the fpn and dmn components , as well as the 2-back vs. rest cope maps .
there was no significant ( t = 1.3 , p = .196 ) difference in fpn subject weights between sz ( mean = .090 , sd = .99 ) and hc ( mean = .057 , sd = 1.00 ) covarying for age and sex .
similarly , there was no significant ( t = .08 , p = .443 ) difference in dmn between sz ( mean = .035 , sd = .99 ) and hc ( mean = .016 , sd = 1.01 ) .
fpn and dmn subject weights were negatively correlated ( across groups : r = .46 , p < .001 ; within sz : r = .40 , p < .001 , within hc : r = .51 ; p < .001 ) , indicating increasing task - positive activations with increasing deactivation of the dmn .
d in 2-back was associated with both functional components ( fpn : t = 5.5 , p < .001 ; dmn : t = 3.4 , p = .001 , covarying for sex , age , diagnosis ) , reflecting increasing fpn activation and dmn deactivation with increasing performance .
rt in 2-back was associated with fpn ( t = 3.0 , p = .004 , covarying for sex , age , diagnosis ) , but not dmn ( t = .80 , p = .424 ) , indicating increasing fpn activation with slower responses .
subject motion showed a significant association with both functional components ( fpn : t = 2.4 , p = .017 ; dmn : t = 2.2 , p = .027 ) , indicating reduced fpn activation and reduced dmn deactivation with increasing motion .
these results ( d , rt , motion ) were highly similar also when not including diagnosis in the model .
permutation testing revealed a significant ( t = 3.0 , uncorrected p = .003 , corrected p < .05 ) association across groups between the fpn component and a component reflecting fronto - temporal thickness ( ic60 ) , indicating stronger fpn activation with increasing thickness .
eight other structure function associations were nominally significant ( p < .05 , uncorrected ) across groups : fpn was associated with components reflecting global surface area ( ic4 ; t = 2.2 , p = .031 ) , global thickness ( ic5 ; t = 2.2 , p = .029 ) , and precentral surface area ( ic62 ; t = 2.7 , p = .009 ) , while dmn was associated with cerebellar gmv ( ic22 ; t = 2.3 , p = .023 ) , frontal thickness ( ic45 ; t = 2.2 , p = .031 ) , temporal gmv ( ic50 ; t = 2.5 , p = .013 ) , precuneal gmv ( ic58 ; t = 2.1 , p = .041 ) , and fronto - temporal thickness ( ic60 ; t = 2.0 , p = .047 ) .
table a.2 also shows the case control differences in structure function associations , as indicated by the interaction term .
none of these remained significant after permutation testing , but the association between dmn and a structural component reflecting frontal gmv ( ic59 ) was at the border of significance ( t = 2.8 , uncorrected p = .005 ; corrected p = .066 ) , indicating reduced dmn deactivation with increased frontal gmv in controls ( t = 2.4 , uncorrected p = .020 ) , and a tendency towards an opposite pattern in sz ( t = 1.8 , uncorrected p = .078 ) .
four other structure function associations showed nominally significant ( p < .05 , uncorrected ) differences between sz and hc : fpn and fronto - temporal thickness ( ic60 ; t = 2.6 , p = .009 ) , dmn and cerebellar gmv ( ic22 ; t = 2.2 , p = .026 ) , dmn and fronto - cingulate surface area ( ic35 ; t = 2.1 , p = .040 ) , and dmn and precuneal gmv ( ic58 ; t = 2.0 , p = .046 ) .
these group differences were mainly driven by significant associations within patients , indicating increased fpn activation with increased fronto - temporal thickness ( ic60 ) , and increased dmn deactivation with increased cerebellar ( ic22 ) and precuneal ( ic58 ) gmv .
dmn and fronto - cingulate surface area ( ic35 ) were not significantly associated in any of the groups .
the association between fpn and fronto - temporal thickness ( ic60 ) was significant at a corrected p - level threshold ( t = 3.0 , uncorrected p = .003 , corrected p = .038 ) .
nominal associations ( p < .05 , uncorrected ) were found between fpn and global surface area ( ic4 ; t = 2.3 , p = .027 ) , global thickness ( ic5 ; t = 2.1 , p = .041 ) , and occipital surface area ( ic66 ; t = 2.0 , p = .048 ) .
dmn was nominally associated with global surface area ( t = 2.4 , p = .017 ) , cerebellar gmv ( ic22 ; t = 2.3 , p = .024 ) , frontal thickness ( ic45 ; b = .28 , t = 2.5 , p = .015 ) , temporal gmv ( ic50 ; t = 2.1 , p = .043 ) , cerebellar - putamen gmv ( ic54 ; t = 2.0 , p = .049 ) , precuneal gmv ( ic58 ; t = 2.1 , p = .035 ) , and fronto - temporal thickness ( ic60 : t = 2.1 , p = .035 ) . within hc , no associations survived permutation testing .
( p < .05 , uncorrected ) were found between fpn and temporal gmv ( ic50 ; t = 2.0 , p = .045 ) and precentral surface area ( ic62 ; t = 2.2 , p = .028 ) , while dmn was associated with temporo - parietal surface area ( ic39 ; t = 2.0 , p = .048 ) and frontal gmv ( ic59 ; t = 2.4 , p = .020 ) . across groups ,
the analysis of conventional structural measures showed associations ( p < .05 , uncorrected ) between fpn and surface area in small clusters mainly in the left precentral , postcentral and inferior temporal gyri ; cortical thickness mainly in the precentral , postcentral , and superior temporal gyri ( fig .
a.1 ) ; and gmv in small clusters in the postcentral gyrus , precuneus , and lateral occipital cortex .
dmn was associated ( p < .05 , uncorrected ) with surface area in small clusters mainly in the medial frontal pole , precuneus , and superior parietal cortex ; cortical thickness in the inferior frontal , precentral , postcentral , and superior temporal gyri ; and gmv in small clusters in the frontal pole , occipital cortex , and middle frontal gyrus . as shown for cortical thickness in fig .
a.1 , these associations were generally more pronounced in patients than in controls , with a main pattern of positive associations with fpn and negative associations with dmn .
the analyses of brain volumes ( table a.4 ) showed that across groups fpn was associated with total cortical volume ( t = 2.0 , p = .046 , uncorrected ) , while there were no associations with any of the other brain structural volumes , and no associations between dmn and brain volumes . within sz
, fpn was associated with total cortical volume ( t = 2.2 , p = .033 , uncorrected ) and total subcortical gray matter volume ( t = 2.2 , p = .034 , uncorrected ) , while dmn was associated with cerebellar volume ( t = 3.0 , p = .003 , uncorrected ) . in hc , no associations were found between functional components and brain volumes .
the association between fpn and fronto - temporal thickness ( ic60 ) , which was significant within sz also at a corrected p - level , remained significant at a nominal level when controlling for the effect of all clinical variables ( fpn ic60 : p < .01 , uncorrected ) , and when including d ( fpn ic60 : p = .013 , uncorrected ) , rt ( fpn ic60 : p = .010 , uncorrected ) , and relative subject motion ( fpn ic60 : p = .002 , uncorrected ) in the model .
when excluding patients with schizoaffective ( n = 15 ) and schizophreniform ( n = 11 ) disorders from the analysis the fpn - ic60 association within patients ( n = 70 ) was not significant , but showed a tendency towards a positive association ( b = .15 , t = 1.4 , p = .178 ) . in line with the results from the main analysis using matched smoothness , the additional analysis with less smoothing on the 3d gmv and cope maps showed a significant association between the fpn resulting from this lica run ( ic2 ) and a component reflecting fronto - temporal thickness ( ic64 ) in sz , which also survived correction for multiple comparisons ( t = 3.2 , uncorrected p = .002 , corrected p = .038 ) . see table a.5 for all within groups associations from this analysis . as shown in fig .
2 , the functional fpn components were highly similar across analyses ( spatial map correlation : r = .93 ; subject weight correlation : r = .95 ) , including the frontal pole , middle frontal gyrus , inferior frontal gyrus , insula , precentral gyrus , paracingulate gyrus , supplementary motor area , lateral occipital cortex and superior parietal lobule in both hemispheres .
the somewhat more extended pattern in the original analysis was due to the higher smoothing level .
the structural fronto - temporal thickness components were also similar across analyses ( spatial map correlation : r = .59 ; subject weight correlation : r = .59 ) , including the superior temporal gyrus , insula , and postcentral gyrus in both hemispheres .
the inferior frontal and precentral gyri showed a stronger involvement in the original analysis , and the insula in the additional analysis , but all these regions were present in both structural components at a z - score threshold <3 , indicating that the components captured the same spatial variability .
using a multivariate approach for multimodal fusing of brain imaging data , we have documented a robust association between task - positive fronto - parietal brain activation and cortical thickness of fronto - temporal regions in sz .
this finding was also confirmed in an additional analysis using less smoothing of fmri and gmv maps . whereas the remaining structure function associations were in general stronger in patients compared to controls
, they were moderate both across , between and within groups , with nominally significant associations . the characteristics and implications of these novel findings will be detailed below .
function relationship was found in sz , between the functional fronto - parietal network ( fpn ) and a structural component reflecting cortical thickness of frontal and temporal brain regions , including the insula .
this association was specific to sz , indicating a disrupted integration of brain structure and function in the implicated brain regions .
the current finding is in line with previous reports of fronto - temporal and insular gray matter reductions in sz ( glahn et al .
, 2010 ; schultz et al . , 2012b ; shepherd et al . , 2012 ) , which may reflect alterations at the neuronal and synaptic level , with consequences for cognitive networks and processing .
evidence from dti studies suggests disruptions of fronto - temporal white matter bundles in sz , including the uncinate fasciculus ( kubicki et al . ,
similarly , functional imaging studies have reported connectivity alterations between frontal and temporal areas ( cocchi et al . , 2014 ; crossley et al . , 2009 ; meyer - lindenberg et al . , 2001 ;
, 2005 ; wolf et al . , 2007 ) , as well as regional abnormalities in frontal ( callicott et al .
2011 ) , temporal ( hugdahl et al . , 2009 ) , and insular ( palaniyappan and liddle , 2012 ; uddin , 2015 ) regions during cognitive processing .
however , the current finding extends previous reports of fronto - temporal abnormalities in sz by suggesting a coupling between cortical thickness in these brain regions and working memory - related brain activation .
the regions involved in the structural and functional components were partly overlapping , e.g. in the insula which shows consistent abnormalities in sz and has been suggested a role in hallucinations ( palaniyappan and liddle , 2012 ) .
however , the main pattern emerging was a lack of anatomical overlap , indicating that activation of the fpn in patients was related to brain structural variability in other regions .
yet the causal relationship is unclear ( see harms et al . , 2013 for discussion ) .
a few other studies have also reported structure function alterations in sz in similar regions using different methodological approaches .
( 2011 ) reported a differential and aberrant association in sz between working memory - related brain activation and fronto - temporal anatomy , though this correlation was negative , indicating decreased activation with increased gray matter volume ( michael et al . , 2011 ) .
( 2013 ) reported that cortical thickness in the left inferior frontal gyrus and insula explained 57% of the variability in task - positive network activation and task - negative deactivation in sz .
however , this study comprised a small number of patients ( n = 14 ) and restricted the analyses to regions showing cortical thinning in the patient group .
the current positive association between fpn and fronto - temporal thickness indicates increased activation with increased thickness . in line with this ,
a positive correlation between anterior cingulate working memory - related activation during a sternberg task and fronto - temporal thickness in sz has been reported ( schultz et al .
the observed association between fpn and fronto - temporal thickness in sz may be related to several factors which should be taken into consideration when interpreting the results , including behavioral effects , clinical variables and patient subgroups .
the structure function association remained significant when controlling for task performance and in - scanner subject motion .
still , behavioral differences within patients may have influenced the findings indirectly , since differences in task performance may reflect illness severity and other aspects of the disorder .
similarly for clinical variables , the association was also present when controlling for the effect of illness duration , current and lifetime symptoms , medication level , and substance use .
however , since this is a naturalistic study , there is an inherent association between clinical severity , symptoms , and medication status , which is difficult to disentangle .
also , since all patients were medicated , it is not possible to isolate effects of disease from effects of medication . in line with this , a recent study ( lesh et al . , 2015 ) showed aspects of this complexity by reporting that cortical thinning , including in fronto - temporal regions , was identified in patients receiving antipsychotic treatment , but not in unmedicated patients , as compared to healthy controls .
the medicated group also presented with higher prefrontal activation and better behavioral performance than the unmedicated group in response to a continuous performance task ( lesh et al . , 2015 ) . due to this complex relationship between medication status and brain alterations in sz
it is unclear to which degree the current findings reflect brain abnormalities related to vulnerability and underlying pathophysiology , or secondary disease- and treatment - related effects . when excluding patients with schizoaffective and schizophreniform disorders , the structure function association in patients largely disappeared , implying that the effect was partly driven by these subgroups .
however , since these groups consisted of 15 and 11 patients only , no clear conclusions should be drawn from this , and further studies are needed to assess the reliability of the present findings . across and between groups ,
the results suggest a complex relationship between brain structure and function , which does not support a direct anatomical overlap . instead ,
as also shown in the main finding , functional networks such as fpn and dmn may rely on brain structural variability in distant regions ( harms et al . ,
2013 ) , which is in line with a system - level perspective of brain function .
further , whereas all effect sizes were moderate , patients in general showed more numerous and stronger associations than hc , in line with recent reports ( fusar - poli et al .
this may be related to factors such as stronger variance in patients and clinical characteristics that are specific to the patient group .
in addition to clinical variables , several factors should be mentioned in relation to the current results .
compared to hc , sz performed significantly worse on the 2-back task , implying reduced target discrimination and slower responses , while there was no group difference in fpn and dmn activations . increased target discrimination was associated with increased fpn activation and dmn deactivation across groups , while slower responses were associated with increased fpn activation .
there was also an effect of subject motion on the functional components , indicating reduced fpn activation and dmn deactivation with increasing subject motion .
these behavioral effects on brain activation may also have influenced the observed structure function associations and the lack thereof .
further , it is not clear to what degree varying spatial smoothing levels of imaging modalities influence lica results . therefore , as a supplement to the main analysis involving comparable smoothness across modalities , we performed an additional analysis using less smoothing on gmv and fmri maps , in order to assess consistency across analyses .
the results showed that the main finding of an association between fpn and fronto - temporal thickness in patients was reliable across approaches and independent of smoothing level , suggesting that robust associations are not sensitive to such variation .
however , since issues related to spatial smoothing are unresolved , future studies should assess the impact of spatial smoothing on the results , and also consider other approaches such as surface - based alignment , which has been shown advantageous in sz ( anticevic et al .
an important question related to the generalizability of the findings is whether lica is sensitive to the same variability as other approaches .
first , this question is relevant to the functional lica components used here and to what degree these are comparable to networks resulting from , e.g. independent component analysis of task- and resting - state fmri data , and from conventional fmri analysis .
encouragingly , even in absence of any time series information in the cope maps submitted to lica , the fpn and dmn components were isolated as separate components that were independent of components reflecting other brain networks ( e.g. visual and lateralized fronto - parietal networks ) .
fpn and dmn also showed a high spatial overlap with the group cope maps reflecting task vs. rest .
second , although univariate and multivariate approaches may in principle target different sources of variability , conventional analyses of structural imaging data yielded an overlapping pattern of nominally significant structure function associations and slightly stronger effects in sz than hc .
similar patterns and directions ( positive / negative ) were found for several structural components , including the fpn association with fronto - temporal thickness in sz .
together , these results show that the current approach detects patterns of structure function relationships which are consistent with conventional structural approaches .
the advantages of lica include that the variation in other components is taken into account when a particular component is investigated , which allows for stronger interpretations regarding specificity .
also , it provides a substantial down - sampling of the multidimensional imaging data , which increases statistical power and facilitates further associations with other variables , including clinical and genetic variability . using a multimodal fusion approach to investigate structure function associations in a large sample of sz and
hc , we found a significant and robust relationship between a task - positive fronto - parietal network and fronto - temporal thickness in sz .
this finding extends previous reports of fronto - temporal abnormalities in sz by suggesting a coupling between cortical thickness in these brain regions and working memory - related brain activation .
Output:
| schizophrenia ( sz ) is a psychotic disorder with significant cognitive dysfunction .
abnormal brain activation during cognitive processing has been reported , both in task - positive and task - negative networks .
further , structural cortical and subcortical brain abnormalities have been documented , but little is known about how task - related brain activation is associated with brain anatomy in sz compared to healthy controls ( hc ) . utilizing linked independent component analysis ( lica ) , a data - driven multimodal analysis approach , we investigated structure function associations in a large sample of sz ( n = 96 ) and hc ( n = 142 ) .
we tested for associations between task - positive ( fronto - parietal ) and task - negative ( default - mode ) brain networks derived from fmri activation during an n - back working memory task , and brain structural measures of surface area , cortical thickness , and gray matter volume , and to what extent these associations differed in sz compared to hc . a significant association ( p < .05 , corrected for multiple comparisons ) was found between a component reflecting the task - positive fronto - parietal network and another component reflecting cortical thickness in fronto - temporal brain regions in sz , indicating increased activation with increased thickness .
other structure function associations across , between and within groups were generally moderate and significant at a nominal p - level only , with more numerous and stronger associations in sz compared to hc .
these results indicate a complex pattern of moderate associations between brain activation during cognitive processing and brain morphometry , and extend previous findings of fronto - temporal brain abnormalities in sz by suggesting a coupling between cortical thickness of these brain regions and working memory - related brain activation . |
PubmedSumm6564 | ***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: renal cell carcinoma ( rcc ) represents the most common cancer of kidney and accounts for approximately 3% of all adult malignancies in western countries ( 1 ) .
rcc remains primarily a surgical disease requiring early diagnosis to optimize the opportunity for cure .
the treatment for patients with rcc who have no clinical signs of distant metastases is radical nephrectomy .
however , metastases occur in approximately 30% of these patients , usually within 1 yr .
moreover 30% of patients already have metastases at the time of presentation ( 2 ) , and in this situation neither chemotherapy nor radiation therapy is effective . despite the lack of an effective systemic therapy ,
a small but significant improvement in overall 5-yr survival has been noted due to early detection and advances in surgical management of the disease ( 3 ) .
a number of investigations have recently undertaken to search for a protein marker for rcc , which can be used for early diagnosis , staging , detection of occult metastatic disease , and to monitor the response to treatment .
however , they have been shown to be either nonspecific or insensitive ( 4 ) .
proteins are key materials to understand cellular functions and disease process , such as tumorigenesis , tumor growth and metastases .
thus , it is expected that protein expression would differ between normal kidney tissue and homologous rcc tissue .
many investigators are currently working on the characterization of rcc using proteome - based techniques .
this technique has been shown to be a useful tool to identify novel proteins for diagnosis and prognosis of malignant disease including colorectal carcinoma ( 5 ) , lung ( 6 ) , and breast cancer ( 7 ) . in rcc , sarto et al .
( 8) reported a number of polypeptides differentially expressed in rcc by comparing 2-dimensional electrophoresis patterns of whole normal kidney epithelium and rcc tissue . in this study , we prepared proteins from the rcc tissue and the homologous normal kidney tissue , and analyzed a number of proteins to isolate and identify tumor - specific proteins of rcc by two - dimensional gel electrophoresis .
the tissue samples of conventional rcc and the surrounding non - cancerous kidney tissues were prepared from surgical specimens of 7 patients after radical nephrectomy .
the study protocol was approved by the human subject research committee of the gyeongsang national university .
part of the sample was immediately frozen in liquid nitrogen and stored at -80 until use .
the frozen kidney tissues were washed several times with phosphate - buffered saline ( ph 7.2 ) to remove cell debris and any remaining blood .
the samples were homogenized in lysis buffer ( 0.3 g tissue / l ml buffer ) ( 8 m urea , 2% chaps , ampholytes and 1 mm pmsf ) , and were centrifuged at 100,000 g for 10 min at 4. the resulting supernatant was kept at -80 until use .
the total protein concentration was determined by the bradford method using bovine serum albumin as a standard ( 10 ) .
the ipg gel strips ( bio - rad , ca , u.s.a . ) were rehydrated in a swelling solution [ 7 m urea , 2% chaps , 100 mm dithiothreitol , 0.5% ipg buffer ( amersham biosciences ) , and bromophenol blue ] that contained 50 g ( for silver staining ) or 500 g ( for coomassie staining ) proteins for 12 hr at 20. isoelectric focusing ( ief ) was performed on immobilized ph gradients ( ipg , ph 4 - 7 , 18 cm ) at 20 in three steps : at 250 v ( 15 min ) , 10,000 v ( 3 hr ) , and then for 40,000 vh using protean ief cell ( bio - rad , ca , u.s.a . ) .
after the ief procedure , the strips were equilibrated with a buffer containing 50 mm tris - hcl , ph 8.8 , 6 m urea , 30% glycerol , 2% sds , and 1% dithiothreitol for 15 min as a first step , and with 2.5% iodoacetamide instead of dithiothreitol for another 15 min as a second step . for sds gel electrophoresis ,
a 7.5 - 17.5% gradient sds gel was prepared , then an equilibrated ipg gel strip was laid on top of the gel and was covered with 0.5% agarose solution .
gel electrophoresis was carried out at 16 at 5 ma / cm ( constant current ) for 1 hr , and then at 10 ma / cm until the bromophenol blue reached the bottom of the gel . for silver staining ,
the gel was fixed in a solution ( 50% methanol and 12% acetic acid ) for 1.5 hr ; washed in 50% ethanol twice for 30 min each time , and then treated with 0.2% sodium sulfoxide for 1 min . after washing with deionized water 3 times for 1 min
the gel was developed in a solution ( 2% sodium bicarbonate , 0.0004% sodium sulfoxide , and 0.5 ml / l formaldehyde ) , and the reaction was stopped by adding 1% acetic acid at the designated time point . for coomassie blue staining , the gel was soaked in a fixation solution ( 30% ethanol , and 2% phosphoric acid ) for 30 min , then in 2% phosphoric acid for 20 min , and equilibrated in a solution ( 2% phosphoric acid , 18% ethanol , and 15% ammonium sulfate ) for 30 min .
the gel was stained in the equilibration solution containing coomassie brilliant blue g-250 for overnight .
the protein patterns in the gel were recorded as digitalized images using a high - resolution scanner ( gs-710 calibrated imaging densitometer , bio - rad , ca , u.s.a . ) .
the scanned gel image was analyzed using a standard protocol for pdquest software ( bio - rad , hercules , ca , u.s.a . ) .
differentially expressed proteins ( p<0.05 by student 's t - test ) were identified in each patient 's tumor sample compared to the corresponding normal kidney sample to form eight independent analyses .
inter - individual comparisons were then made by comparison of reference gels and protein spots found to be significantly higher or lower in all tumor samples compared to corresponding normal kidney samples . for protein identification , we used a voyager -de ( delayed extraction ) str biospectrometry workstation ( applied biosystems , forster city , ca , u.s.a . ) for maldi - tof mass spectrometry .
the gel pieces containing the desired protein spots were excised , washed and digested in gel with trypsin ( sequencing grade , boehringer mannheim ) ( 11 ) .
the search for protein identity was performed with reference to the public sequence databases ( swiss - prot or ncbi ) using ms - fit ( http://prospector.ucsf.edu/ucsfhtml13.4/msfit.htm ) .
the tissue samples of conventional rcc and the surrounding non - cancerous kidney tissues were prepared from surgical specimens of 7 patients after radical nephrectomy .
the study protocol was approved by the human subject research committee of the gyeongsang national university .
part of the sample was immediately frozen in liquid nitrogen and stored at -80 until use .
the frozen kidney tissues were washed several times with phosphate - buffered saline ( ph 7.2 ) to remove cell debris and any remaining blood .
the samples were homogenized in lysis buffer ( 0.3 g tissue / l ml buffer ) ( 8 m urea , 2% chaps , ampholytes and 1 mm pmsf ) , and were centrifuged at 100,000 g for 10 min at 4. the resulting supernatant was kept at -80 until use .
the total protein concentration was determined by the bradford method using bovine serum albumin as a standard ( 10 ) .
the ipg gel strips ( bio - rad , ca , u.s.a . ) were rehydrated in a swelling solution [ 7 m urea , 2% chaps , 100 mm dithiothreitol , 0.5% ipg buffer ( amersham biosciences ) , and bromophenol blue ] that contained 50 g ( for silver staining ) or 500 g ( for coomassie staining ) proteins for 12 hr at 20. isoelectric focusing ( ief ) was performed on immobilized ph gradients ( ipg , ph 4 - 7 , 18 cm ) at 20 in three steps : at 250 v ( 15 min ) , 10,000 v ( 3 hr ) , and then for 40,000 vh using protean ief cell ( bio - rad , ca , u.s.a . ) .
after the ief procedure , the strips were equilibrated with a buffer containing 50 mm tris - hcl , ph 8.8 , 6 m urea , 30% glycerol , 2% sds , and 1% dithiothreitol for 15 min as a first step , and with 2.5% iodoacetamide instead of dithiothreitol for another 15 min as a second step . for sds gel electrophoresis
, a 7.5 - 17.5% gradient sds gel was prepared , then an equilibrated ipg gel strip was laid on top of the gel and was covered with 0.5% agarose solution .
gel electrophoresis was carried out at 16 at 5 ma / cm ( constant current ) for 1 hr , and then at 10 ma / cm until the bromophenol blue reached the bottom of the gel . for silver staining ,
the gel was fixed in a solution ( 50% methanol and 12% acetic acid ) for 1.5 hr ; washed in 50% ethanol twice for 30 min each time , and then treated with 0.2% sodium sulfoxide for 1 min . after washing with deionized water 3 times for 1 min
each , the gel was impregnated in a solution ( 0.2% silver nitrate and 0.75 ml / l formaldehyde ) for 20 min and washed twice in water .
the gel was developed in a solution ( 2% sodium bicarbonate , 0.0004% sodium sulfoxide , and 0.5
ml / l formaldehyde ) , and the reaction was stopped by adding 1% acetic acid at the designated time point . for coomassie blue staining , the gel was soaked in a fixation solution ( 30% ethanol , and 2% phosphoric acid ) for 30 min , then in 2% phosphoric acid for 20 min , and equilibrated in a solution ( 2% phosphoric acid , 18% ethanol , and 15% ammonium sulfate ) for 30 min .
the gel was stained in the equilibration solution containing coomassie brilliant blue g-250 for overnight .
the protein patterns in the gel were recorded as digitalized images using a high - resolution scanner ( gs-710 calibrated imaging densitometer , bio - rad , ca , u.s.a . ) .
the scanned gel image was analyzed using a standard protocol for pdquest software ( bio - rad , hercules , ca , u.s.a . ) .
differentially expressed proteins ( p<0.05 by student 's t - test ) were identified in each patient 's tumor sample compared to the corresponding normal kidney sample to form eight independent analyses .
inter - individual comparisons were then made by comparison of reference gels and protein spots found to be significantly higher or lower in all tumor samples compared to corresponding normal kidney samples . for protein identification , we used a voyager -de ( delayed extraction ) str biospectrometry workstation ( applied biosystems , forster city , ca , u.s.a . ) for maldi - tof mass spectrometry .
the gel pieces containing the desired protein spots were excised , washed and digested in gel with trypsin ( sequencing grade , boehringer mannheim ) ( 11 ) .
the search for protein identity was performed with reference to the public sequence databases ( swiss - prot or ncbi ) using ms - fit ( http://prospector.ucsf.edu/ucsfhtml13.4/msfit.htm ) .
we analyzed the proteomic profiles of the rcc tissue and the corresponding normal kidney tissues from 7 consecutive patients with conventional rcc .
the mean age of the patients was 65.4 yr ( range 54 to 78 ) .
the samples were examined histologically to verify the macroscopic cell type ( benign or cancer ) .
spots representing proteins that were differentially expressed in rcc were selected ( p<0.05 by student 's t - test ) .
a total of 905 spots from a conventional rcc samples and 953 spots from a corresponding normal kidney samples were visualized in a gel ( ph range from 4.0 - 7.0 and a molecular mass range from 10 - 100 kda ) ( fig .
the overall protein expression patterns in clear cell rcc and normal kidney tissues were quite similar except for some areas .
ten specific regions containing some proteins differentially expressed in rcc and normal tissues were further analyzed by comparing their expression patterns in all 7 patients .
for the assessment of differentially expressed proteins only protein spots altered in all tumor samples were considered .
the protein identities from all the spots were entered in the composite gel database so that any changes in the protein expression could be determined for each protein spot .
the integrated protein intensity was determined for each identified spot in seven gels each from the rcc tissues and corresponding normal kidney tissues .
the mean intensity of each spot was calculated by its silver stain intensity and the relative intensities between the rcc tissues and normal tissues .
two proteins were dominantly expressed in the conventional rcc and six proteins were revealed largely repressed , these proteins were found with a statistical significance .
some of these proteins have been identified by mass spectrometry . a typical mass spectrum of a protein , aldehyde reductase , is shown in fig .
the expression level of each protein in both rcc and normal tissue was indicated by the density values ( fig . 3 , 4 ) .
their predicted values of isoelectrical point ( pi ) and molecular weight ( mw ) are summarized in table 2 , and the values were compatible to those of acquired from the gels .
the sequence coverage of proteins isolated from the peptide mass matching in a program was acceptable ( 19 - 55% ranges ) .
these rows of protein spots , which typically had similar molecular sizes but slightly different isoelectrical points , probably were due to posttranslational modifications that change in the protein charge .
the protein identities from all spots were entered in the composite gel database so that changes in protein expression could be determined for each protein spot .
integrated protein intensity was determined for each identified spot in seven gels each from rcc and corresponding normal kidney tissues .
the mean intensity of each spot was calculated by silver stain intensity , and relative intensities between rcc and normal tissues were compared .
six proteins showed largely repressed expression in rcc with a statistical significance ; aminoacylase-1 in region 1 , enoyl - coa hydratase in region 2 , agmatinase and ketohexokinase in region 4 , aldehyde reductase in region 5 and tropomyosin -4 chain in region 9 ( fig . 1 , 3 ) .
two proteins were dominantly expressed in rcc ( fig . 1 , 4 ) ; -1 antitrypsin precursor in region 3 and vimentin in region 7 .
the proteomic approach shows great potential to be a powerful tool for the identification of proteins differentially expressed in the normal kidney tissue and rcc tissue , and the characterization of the newly isolated rcc - specific markers might allow for a better subclassification of rcc and the early diagnosis of this disease . in this study ,
66 proteins were shown to have either increased or decreased expression ( 2 ) in rcc ( data not shown ) . some of these proteins have previously been shown to have an altered expression in rcc . among them , five proteins were identified as vimentin ( 12 ) , aminoacylase-1 , enoyl - coa hydratase ( 13 ) , aldehyde reductase ( 14 ) , and agmatinase by using maldi - tof mass spectrometry ( 15 ) .
vimentin , one of the cytoskeletal proteins , was significantly overexpressed in rcc tissue compared with the corresponding normal tissue . a proteome - based study demonstrated a heterogeneous expression pattern of vimentin in different rcc subtypes ( 12 ) .
it is often associated with cellular differentiation , invasion , migration and metastatic potential of tumors ( 16 ) .
aminoacylase-1 , which is found in many mammalian tissues with the highest activities occurring in the kidney , is usually involved in detoxification processes .
it hydrolyzes a variety of n - acylated amino acids generating free amino acids and may be involved in the synthesis of hippurate that is formed during detoxification of aromatic compounds ( 17 ) .
a diminished expression of this enzyme has also been found in lung cancer cell lines of small cell type and pulmonary tumors ( 18 ) .
the von hippel - lindau ( vhl ) gene , a tumor suppressor gene , is located on chromosome 3p25-p26 ( 19 ) , and the vhl gene mutations were detected in a high percentage of tumors from patients with conventional rcc ( 20 ) . in line with the previous observation , enoyl - coa hydratase , a short - chain mitochondrial enoyl - coa hydratase , involved in mitochodrial -oxidation , was shown to have decreased expression in rcc ( 13 ) .
aldehyde reductase is an oxidoreductase that catalyzes nadph - dependent reduction of a variety of aromatic and aliphatic aldehydes ( 21 ) .
this enzyme is important because of its ability to detoxify a variety of reductive aldehyde species and metabolize certain steroid and neurotransmitter metabolites and glucuronate ( 22 ) , however , little is known about its physiological role .
g250-treated and untreated rcc cell lines were investigated for their protein expression profiles to identify tumor markers , which may allow the selection of patients prior to specific immunotherapy .
they found decreased expression of aldehyde reductase in g250-treated rcc cell line ( 14 ) .
recently , dallmann et al . ( 15 ) reported that human agmatinaes is diminished in the clear cell type of rcc by proteomic approach .
rt - pcr and nothern blot analyses demonstrated a clearly decreased amount of agmatinase mrna in tumor cells , and they confirmed the differential expression of agmatinase mrna at the protein level by western blot analysis .
the expression of agmatinase in this study was also diminished in rcc compared with that in the normal counterpart of kidney ( fig .
antitrypsin precursor , which present in the proximal tubule of kidney , showed an increased expression in the tumor . based on the histochemical profile of normal kidney , carcinoma , and oncocytoma , 89% of rcc and 50% of oncocytoma expressed -1 antitrypsin activity ( 23 ) .
-1 antitrypsin is a broad spectrum inhibitor of serine proteases , including trypsin protease , chymotrypsin protease , and elastase like enzyme ( 24 ) .
its major physiological role is the inhibition of leukocytes elastases released at sites of inflammation .
the function of -1 antitrypsin released by epithelial cells is still unclear , although they may play a role in the regulation of growth and proliferation processes . in this study , this enzyme was overexpressed in rcc tissue , suggesting the tumor tissues might need the -1 antitrypsin activity .
a significantly heterogeneous expression pattern of the different members of the cytoskeleton was found between different rcc cell lines and by comparison of rcc cell lines with corresponding kidney epithelium cell lines .
tropomyosin -4 chain , one of the cytoskeletal proteins , showed a decreased expression in rcc .
it is noteworthy that with the exception of cytoskeletal tropomyosin , cytoskeletal proteins seem to be readily recognized by patients with rcc than by control sera .
the reason for the relatively high frequency of cytoskeletal tropomyosin autoantibodies in control sera and their potential role in the development of autoimmune disease requires further investigation using a larger sample number ( 12 ) .
it might be suggested that the loss of potential tumor antigens over time represents an effective strategy of tumors to evade immune recognition .
much of the ingested fructose is metabolized by the liver , using fructose 1-phosphate pathway , and then can be funneled into the universal glycolytic pathway . although ketohexokinase is most abundant in the liver , it is also found in the kidney , small intestine , and pancreas ( 25 ) .
glycolysis takes place predominantly in the distal segments of renal tubular system . during the development of rat renal basophilic cell tumors
a predominant biochemical alteration in cancer cells is a markedly elevated rate of glucose catabolism ( 27 ) .
thus , it has been observed that activities of key glycolytic enzymes such as hexokinase and pyruvate kinase are increased in tumor cells compared with normal cells from their tissue of origin .
nonetheless , the increased glycolysis can not be considered as a general phenomenon in neoplasm .
some brain neoplasm , for example , neuroblastomas ( 28 ) , and retinoblastoma ( 29 ) show decreased hexokinase activity compared with normal brain .
however , it might also be suggested that different types of rcc represent different expression pattern of ketohexokinase , which is eventually involved in glycolysis . in conclusion ,
two - dimensional polyacrylamide gel electrophoresis is a powerful tool to comprehensively analyze total proteins that are differentially expressed in rcc .
we compared proteomes of the normal human kidney with that of the corresponding renal cell carcinoma tissues in gels , and identified differentially expressed proteins by mass spectrometry .
the expression of six proteins , aminnoacylase-1 , enoyl - coa hydratase , aldehyde reductase , tropomyosin -4 chain , agmatinase and ketohexokinase , was decreased in rcc .
the study of the protein expression in rcc and the normal kidney tissue may help us to find tumor - specific proteins of these diseases .
Output:
| renal cell carcinoma ( rcc ) is one of the most malignant tumors in urology , and due to its insidious onset patients frequently have advanced disease at the time of clinical presentation .
thus , early detection is crucial in management of rcc . to identify tumor specific proteins of rcc
, we employed proteomic analysis .
we prepared proteins from conventional rcc and the corresponding normal kidney tissues from seven patients with conventional rcc .
the expression of proteins was determined by silver stain after two - dimensional polyacrylamide gel electrophoresis ( 2d - page ) .
the overall protein expression patterns in the rcc and the normal kidney tissues were quite similar except some areas . of 66 differentially expressed protein spots ( p<0.05 by student t - test ) , 8 different proteins from 11 spots were identified by maldi - tof - ms .
the expression of the following proteins was repressed ( p<0.05 ) ; aminoacylase-1 , enoyl - coa hydratase , aldehyde reductase , tropomyosin -4 chain , agmatinase and ketohexokinase . two proteins , vimentin and -1 antitrypsin precursor , were dominantly expressed in rcc ( p<0.05 ) . |
PubmedSumm6565 | ***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: osteonecrosis of the jaw ( onj ) emerged as a well - known devastating side effect of parenteral bisphosphonate therapy since the widespread use of biphosphonates to reduce skeletal related events ( sre ) .
biphosphonates are commonly used every three to four weeks with around 1448% reduction of sre occurrence and onj occurrence in 1.23.8% despite preventive measures , , , .
although the positive results of 4 different trials , the use of biyearly biphosphonates regimens to reduce aibl is not approved , , , . this spaced interval of six months achieved an increase in median bone mineral density of 2.74.3% in the lumbar spine and 1.61.7% in the hip when used in post - menopausal women receiving adjuvant hormonal aromatase inhibitor , . however , the risk of developing onj with the bi - annually regimen of zoledronic acid is not well recognized .
a review of literature in women having breast cancer receiving zoledronate biannually to prevent aibl was conducted . reported cases of onj are collected from the selected studies and an estimation of the onj risk in this category of patients is reported .
electronic searches of the literature published until september 2014 were conducted using pubmed and the cochrane collaboration database to identify articles evaluating the onj as a side effect in women receiving zoledronic acid every six months for the prevention of aromatase inhibitor associated bone loss ( aibl ) in patients with early stage breast cancer . only randomized and non - randomized controlled clinical trials were included .
zoledronic acid , early breast cancer and aromatase inhibitors. this search was augmented by a hand search of the reference lists of relevant articles included in the literature review .
two different investigators performed the search and the abstracts were independently reviewed for possible inclusion .
types of participants : included studies were limited to post - menopausal women receiving zoledronic acid every six months with aromatase inhibitors to prevent aibl .
selection of studies : the articles were first selected individually on the basis of their titles by two of the authors .
electronic searches of the literature published until september 2014 were conducted using pubmed and the cochrane collaboration database to identify articles evaluating the onj as a side effect in women receiving zoledronic acid every six months for the prevention of aromatase inhibitor associated bone loss ( aibl ) in patients with early stage breast cancer . only randomized and non - randomized controlled clinical trials were included .
zoledronic acid , early breast cancer and aromatase inhibitors. this search was augmented by a hand search of the reference lists of relevant articles included in the literature review .
two different investigators performed the search and the abstracts were independently reviewed for possible inclusion .
types of participants : included studies were limited to post - menopausal women receiving zoledronic acid every six months with aromatase inhibitors to prevent aibl .
selection of studies : the articles were first selected individually on the basis of their titles by two of the authors .
the upfront biyearly regimen of zoledronic acid significantly increased bone mineral density ( bmd ) in postmenopausal women receiving aromatase inhibitors for early breast cancer , , , .
the z - fast trial enrolled 602 postmenopausal women with early hormone receptor - positive breast cancer receiving adjuvant letrozole .
patients were randomized equally to receive upfront or delayed zoledronic acid with a 4 mg intravenous regimen every 6 months for 5 years .
the investigators reported two cases of onj in the upfront group during the 60 months follow - up .
however , an onj adjudication committee deemed one of the cases inconsistent with onj and the other one indeterminate because of insufficient information .
the zo - fast trial recruited 1065 postmenopausal women receiving adjuvant letrozole that were randomly assigned to immediate zoledronic acid with a regimen of 4 mg every 6 months for 5 years , or delayed administration initiated at fracture occurrence or on - study bmd decrease .
a total of nine potential onj events from seven patients were reported in this study after 60 months follow up .
each event was independently adjudicated by an external panel that confirmed onj occurrence in three cases , deemed possible for insufficient data in two cases , and excluded the remaining cases .
therefore , in the zo - fast trial , onj occurred in 0.280.47% . in the e - zo - fast trial , 527 postmenopausal women receiving aromatase inhibitors were randomized to either immediate or delayed zoledronic acid treatment , at 4 mg every 6 months .
two reported cases of onj of the immediate zoledronic acid group were confirmed by the adjudication committee . at diagnosis
finally , the abcsg-12 trial is the largest study recruiting 1803 patients with early breast cancer receiving zoledronic acid 4 mg intravenously every 6 months .
all these studies are summarized in the table 1 . keeping in mind the limitation of these studies by the absence of long - term follow - up , the mean risk of developing onj varies between 0.230.41% in patients receiving immediate or late zoledronic acid .
zoledronic acid has been approved for prevention and treatment of osteoporosis and glucocorticoids - induced osteoporosis , treatment of paget 's disease , hypercalcemia , multiple myeloma and bone metastasis . in the particular case of breast cancer , it is recommended as a monthly administration in breast cancer patients with bone metastasis and as a biyearly administration in early breast cancer patients receiving adjuvant aromatase inhibitors for aibl prevention .
it is incorporated into the skeleton without being degraded and consequently decreases bone turnover and inhibits of the bone 's reparative ability , .
reports of the side effects of zoledronic acid most commonly describe bone pain , nausea , fever , fatigue and constipation .
onj is an uncommon , but severe , adverse event that has been reported with prolonged zoledronic acid therapy . in women with advanced breast cancer and bone metastases ,
the use of bisphosphonates in adjunction to hormone therapy or chemotherapy reduces the sre occurrence and the sre rate , as well as increases the time to skeletal event occurrence .
effectively , breast cancer patients receiving bisphophonates represent more than 20% of patients developing onj .
metastatic breast cancer patients treated by zoledronic acid monthly develop onj in 1.23.8% with the long - term treatment , . on the other hand ,
biyearly zoledronic acid for aibl prevention in early breast cancer is complicated with onj in less than 0.7% according to our literature review . unfortunately , these trials did not report the time of occurrence of the onj , , .
however , the azure trial used a regimen that consisted of monthly zoledronic acid for six doses then every three to six months to compete the 5 years treatment and reported a comparable prevalence of onj .
this comparison allows a safe administration of the loading dose of zoledronic acid .
effectively , the pharmacology of the zoledronic acid characterized by a long half - life correlates well with this finding . a recently published abstract , swog 0307 compared three different bisphosphonates clodronate , ibandronate and zoledronic acid administred in a specific schedules in the adjuvant setting of early breast cancer .
no evidence of differences in efficacy by type of bisphosphonate either in the intent to treat analysis or based on age and menopausal status was detected between the three arms . at 5 years
follow - up , the rate of onj was 1.2% in zoledronic acid arm administered monthly for six months then every 3 months for 2.5 years .
denosumab , a fully monoclonal antibody rankl inhibitor , was also evaluated at 60 mg every six months instead of zoledronic acid in patients presenting aromatase inhibitor associated bone loss in early breast cancer . in abcsg
18 trial comparing denosumab 60 mg every six months to placebo , 3425 patients were included ; overall lower number of fractures was demonstrated in the denosumab arm versus the placebo arm .
35 dental problems were identified by proactive monitoring of onj during the trial , 31 suspected cases of onj were detected but no case was eventually judged to meet the diagnosis criteria of onj .
denosumab seems to be safer concerning onj in the indication compared to zoledronic acid ; a randomized trial comparing these two agents can only confirm this hypothesis .
osteonecrosis of the jaw is a major complication of monthly biphosphonate regiments that seems to be encountered also in biyearly administration .
the literature review on zoledronic acid given every six months to prevent aibl , showed a relatively low risk for onj not exceeding 0.7% . despite this low prevalence , avoidance of dental manipulation and recommendations of oral hygiene
Output:
| osteonecrosis of the jaw ( onj ) is one of the most relevant and specific complication of biphosphonates .
onj in patients receiving zoledronic acid every 3 to 4 weeks is frequently described , but the onj biyearly regimen used to reduce aromatase inhibitor associated bone loss ( aibl ) , is rarely reported . a literature review , focusing on the important trials using zoledronic acid to reduce aibl , found that the mean risk of developing onj when zoledronic acid is used biyearly varies between 0.12% and 0.7% . |
PubmedSumm6566 | ***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 was established by the 1980 's that drug treatment of elevated blood pressure ( bp ) reduces the risks of cardiovascular complications of hypertension .
the prevailing assumption among clinicians and regulators was , and probably continues to be , that the benefits of antihypertensive treatment were a direct consequence of the reduction in systolic and/or diastolic bp .
based on this premise , we have seen a flood of new antihypertensive agents from multiple classes of drugs introduced into the marketplace .
the scientific documentation has often consisted of small , short - term trials . as long as the new agents are superior to placebo in reducing bp , and as long as they are reasonably free of side effects , the drugs receive regulatory approval .
clinicians now have more than 100 antihypertensive drugs from which to choose . because the blood - pressure - lowering potential of these drugs is fairly similar , use of individual pharmaceutical agents is determined more by marketing forces than by science .
a health services concern is that there is a greater than 20-fold difference in drug cost .
the key question today is , " does it matter how elevated bp is lowered ? "
this question is best answered by randomized clinical trials that compare antihypertensive agents . however , a number of issues and concerns have been raised about the design of these trials .
regulatory agencies prefer placebo - controlled trials , since they want to know whether a drug is effective for its intended use and whether it is reasonably safe .
comparative or active - controlled trials have other objectives and provide answers along the superiority inferiority axis .
although extremely relevant clinically , the regulatory agencies have limited interest and use for information regarding which drug is superior .
comparative trials are a cause for concern to the pharmaceutical industry , since such trials may produce losers ( inferior drugs ) , whereas the outcome of placebo - controlled trials of new antihypertensive agents is , for the industry , less risky . to lessen the risks that a drug may be inferior to that of a competitor
, there is an unfortunate tendency to compare the new agent to the least effective standard therapy , sometimes in an inadequate dose .
another approach is to proceed with only a small sample size , which is inadequate to detect reliably meaningful differences among drugs .
the antihypertensive and lipid - lowering treatment to prevent heart attack trial ( allhat ) , initiated in 1994 , was one of the first major comparative trials with clinical outcomes .
its strengths include : independent sponsorship ( the national heart , lung , and blood institute ) ; its scope ( comparison of 4 drugs from different drug classes ) ; optimal selection of standard / control treatment ( low - dose diuretics ) ; a double blind design ; its sample size ( 40,000 high - risk hypertensives to be treated for 48 years ) ; and the selection of trial outcomes ( all major vascular complications of hypertension ) .
allhat addresses the question of whether representatives of the newer and more expensive antihypertensive agents : lisinopril ( angiotensin - converting enzyme inhibitor ) , doxazosin ( alpha - blocker ) , and amlodipine ( calcium - channel blocker ) , are more effective as first - line drugs than a generic agent , chlorthalidone ( low - dose diuretic ) , in reducing the risk of cardiovascular disease .
first , there was a highly significant ( 25% ) excess risk of major cardiovascular events ( a prespecified secondary endpoint ) in the doxazosin group in comparison to the chlorthalidone group .
second , the likelihood of doxazosin emerging as superior to low - dose chlorthalidone was very remote .
this excess of cardiovascular events with doxazosin was driven by a doubling in the risk of congestive heart failure , both primarily hospitalized and fatal cases .
the annual heart failure rate was 2% in the doxazosin group but 1% in the chlorthalidone group .
in addition , there was a 20% excess in the relative risk of stroke , and 15% excesses in coronary revascularizations and angina , in the doxazosin group .
however , the risks of major coronary events ( the prespecified primary endpoint ) and all - cause mortality were not different between the two treatment groups .
the fact that the achieved blood pressures were similar throughout the duration of the trial indicates that non - blood - pressure - related mechanisms are involved , which could explain these differences .
the more persuasive ones conclude that alpha - blockers should no longer be considered first - line agents for hypertension in high - risk , elderly adults [ 4 - 6 ] . others raise questions of a technical nature , but fail to realize the public health implication of the allhat findings [ 7 - 9 ] . among the approximately one million users of doxazosin in the united states and europe
, one could expect as many as 10,000 unnecessary cases of advanced heart failure every year .
krakoff raises a critical question , " should the results of allhat be considered as revealing drug toxicity or of the lesser charge of ineffectiveness ? "
he suggests that doxazosin , " may be ineffective and perhaps little better than placebo , for the many patients at higher risk for heart failure " .
regardless of the answer , actions should be taken to inform treating clinicians . to date , the manufacturer of doxazosin , pfizer , has refused to issue even a " dear doctor " letter with a proper warning . the other two commentaries by gavras and gavras and hooper discuss potential mechanisms behind the observed excess of cardiovascular events .
gavras and gavras speculate that alpha - adrenergic blockage would lead to small elevations of arginine vasopressin .
this systemic pressor hormone could become important through its pressor action in elderly patients and in those with diabetes , triggering congestive heart failure and myocardial ischemia .
these proteins have vital functions in the body , protecting cells from injury through multiple mechanisms .
alpha - adrenergic stimulation with norepinephrine increases the levels of heat shock proteins , while alpha - adrenergic blockade decreases it .
a drug - induced decrease could lead to increased vulnerability of the cardiovascular system to injury .
. we may never know with certainty why doxazosin had unfavorable cardiovascular effects in allhat .
however , we stand on a solid scientific foundation when we conclude that doxazosin is an inferior antihypertensive agent and it should only be used if first - line agents low - dose diuretics , beta - blockers , and angiotensin - converting enzyme inhibitors fail to achieve blood pressure control or can not be tolerated .
Output:
| the key question in hypertension research today is , " does it matter how elevated blood pressure is lowered ? "
the antihypertensive and lipid - lowering treatment to prevent heart attack trial ( allhat ) initiated in 1994 serves as a model for comparative trials .
its strengths include its independent sponsorship , scope and design .
the alpha - blocker arm was stopped early ; doxazosin was shown to be clearly inferior to low - dose chlorthalidone not only in preventing heart failure , but also stroke , in spite of similar blood pressure reduction .
the findings have major public health implications as pointed out by krakoff in this journal .
other commentaries by gavras and gavras and hooper discuss possible mechanisms behind the excess of cardiovascular events in doxazosin - treated patients . |
PubmedSumm6567 | ***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: bullous pemphigoid ( bp ) , the most common autoimmune blistering disease , is mediated by autoantibodies .
bp primarily affects the elderly and is characterized by the development of urticarial plaques surmounted by subepidermal blisters , and the deposition of immunoglobulins and complement at the basement membrane zone ( bmz ) of the skin .
bp is immunologically characterized by the development of autoantibodies targeting two structural proteins of the hemidesmosomes , bp180 ( collagen xvii ) and bp230 ( bpag1 ) .
a 63 -year - old caucasian female patient was evaluated for a 4 day history of several itching , erythematous blisters on her extremities .
biopsies for hematoxylin and eosin ( h&e ) examination , as well as periodic acid - schiff ( pas ) , immunohistochemistry ( ihc ) and direct immunofluorescence ( dif ) analysis were performed .
h&e demonstrated a subepidermal blister , with partial re - epithelialization of the blister floor . within the blister lumen ,
numerous neutrophils were present , with occasional eosinophils and lymphocytes also noted . within the dermis ,
a mild , superficial , perivascular and periadnexal infiltrate of lymphocytes , histiocytes and occasional eosinophils was identified , with mild perivascular leukocytoclastic debris .
the pas stain was positive at the bmz , and around selected blood vessels , nerves and sweat glands .
dif revealed linear deposits of igg and complement / c3 and fibrinogen at the bmz , and around selected dermal nerves , blood vessels and sweat glands .
strong granular deposits of ige were also observed , colocalizing with monoclonal antibodies to collagen iv ( civ ) . by ihc ,
positive cd45 staining of lymphocytes was seen surrounding selected dermal blood vessels , eccrine sweat glands , and nerves .
the patient displayed igg , ige , and fibrinogen autoantibodies against the bmz , as well as around some dermal nerves and sweat glands ; their binding in the skin could trigger complement activation .
bullous pemphigoid ( bp ) is an autoimmune blistering disease primarily affecting elderly patients , and characterized by the development of urticarial plaques surmounted by subepidermal blisters and the deposition of both immunoglobulins and complement at the basement membrane zone ( bmz ) of the skin .
immunologically , it is characterized by the development of autoantibodies targeting two important proteins of the hemidesmosomes , bp180 ( collagen xvii ) and bp230 .
it is known that bp230 is an intracellular protein of the hemidesmosomal plaque , while bp180 is a transmembrane protein containing a collagenous extracellular domain .
autoantibodies are of both the igg and ige classes ; their binding in the skin triggers complement activation , mast cell degranulation and additional migration of eosinophils , mast cells , and neutrophils[14].discharge of proteases from these inflammatory cells may result in cleavage of the bmz and subsequent blister formation .
a 63 year old female patient was referred with a four day history of several , severely pruritic , erythematous blisters and crusts on her extremities ( arms and thighs ) ( fig .
skin biopsies for hematoxylin and eosin ( h & e ) , as well as for periodic acid - schiff ( pas ) and immunohistochemistry ( ihc ) were performed .
in addition , direct immunofluorescence ( dif ) and indirect immunofluorescence ( iif ) with 0.1 m sodium chloride salt split skin were performed . in brief
, dif was performed utilizing skin cryosections , incubated with multiple fluorescein isothiocyanate ( fitc)-conjugated secondary antibodies .
the secondary antibodies were of rabbit origin , and included : a ) anti - human igg ( chain ) , b ) anti - human iga ( chains ) , c ) anti - human igm ( -chain ) , d ) anti - human fibrinogen , and e ) anti - human albumin ( all used at 1:20 to 1:40 dilutions and obtained from dako ( carpinteria , california , usa ) .
we also utilized secondary antibodies of goat origin , including : a ) anti - human ige antiserum ( vector laboratories , bridgeport , new jersey , usa ) and b ) anti - human c1q ( southern biotech , birmingham , alabama , usa ) .
finally , monoclonal anti - mouse collagen iv ( civ ) from invitrogen(carlsbad , california , usa ) with a goat anti - mouse texas red conjugated secondary antibody was utilized to highlight the basement membrane zone ( bmz ) .
the slides were then counterstained with 4,6-diamidino-2-phenylindole ( dapi ) ( pierce , rockford , illinois , usa ) washed , coverslipped , and dried overnight at 4c .
ihc staining using anti human cd45 was performed using a dako automatized dual endogenous flex system , following dako technical instructions . in figure 1 , we highlight our most significant h & e , pas , dif and ihc results , including localization of the bmz autoantibodies utilizing the iif sodium chloride split skin technique . the dif results in the basement membrane zone of the skin ( bmz ) were as follows : igg , linear , + + ; ige , granular , + + ; c3 , linear , + + ; fibrinogen , linear , + + ; complement / c1q , linear , + /-
; fibrinogen , linear , + + , and collagen iv , linear , + + . within the dermis , we observed ige , fibrinogen and c3 perineural and sweat gland reactivity ( + + ) .
indirect immunofluorescence(iif ) performed on 1 m nacl salt split skin displayed the following results : igg ( + , linear , blister roof ) ; iga ( + , linear , blister roof ) ; igm ( + , linear , blister roof ) ; ige ( + , dermal perivascular and perineural ) ; complement / c1q(+ , linear , blister roof ) ; complement / c3 ( + , linear , blister roof ) ; albumin(+ , linear , blister roof ) ; and fibrinogen ( + , linear , blister roof ) .
h & e staining ( 100x ) demonstrating the subepidermal blister ( red arrow ) . 1b ,
dif , positive staining with fitc conjugated anti - human ige at the bmz in a linear pattern ( green staining , lower white arrow ) , colocalizing with the collagen iv(civ ) antibody ( red staining , top yellow arrow ) .
please notice that civ also stains the upper dermal blood vessel areas ( lower yellow arrow ) .
dif , showing destruction of epidermal keratinocytes , characterized by amorphous staining of cell nuclei with dapi ( blue staining , yellow arrows ) .
the red arrow shows defragmented pieces of civ in the blister lumen ( red particles ) ; the white arrows show positive staining with fitc conjugated antihuman fibrinogen , on both sides of the blister ( epidermal and dermal ) .
1d , shows a clinical blister ( white arrow ) and some adjacent crusts ( blue arrows ) .
note the keratinocytes nuclei in blue ( dapi ) , and the mapping of the blister with civ antibody ( red staining , yellow arrows ) .
please note the delicate , trans - epidermal excretion of tiny fragments of civ , seen as small red dots among the keratinocytes .
. periodic acid - schiff ( pas ) stain , displaying pink positivity at the bmz ( red arrow ) .
positive staining of a nerve with fitc conjugated anti - human fibrinogen ( green staining ; red arrows ) , as well as against eccrine sweat glands ( yellow arrows ) .
the identity of the nerve was confirmed by colocalizing , positive s-100 ihc staining ( brown staining , red arrow ) .
in addition , we utilized ihc to confirm a significant lymphocytic infiltrate around dermal neurovascular package and eccrine sweat glands with cd45 ( brown staining , red arrows ) .
. 1k , dif positive staining of a blood vessel wall with fitc conjugated complement / c3 ( green - yellowish staining , yellow arrow ) , colocalizing with civ antibody ( red staining , red arrows ) .
1 m . h & e stain , showing lymphocytes infiltrating around dermal nerves ( black arrow ) , eccrine sweat glands ( yellow arrow ) and an eccrine sweat gland ductus ( blue arrow ) .
pas positive staining of eccrine sweat gland peripheral membranes ( pink staining , black arrows ) .
examination of the h&e tissue sections demonstrated a subepidermal , tense blister , with partial re - epithelialization of the blister floor .
a mild , superficial , perivascular and periadnexal infiltrate of lymphocytes , histiocytes and occasional eosinophils was identified .
a pas special stain displayed positivity at the basement membrane zone ( bmz ) , as well as around some dermal blood vessels , nerves and eccrine sweat glands ( fig .
bullous pemphigoid and epidermolysis bullosa acquisita ( eba ) may have indistinguishable clinical , histologic , and routine immunofluorescence features .
thus , these two diseases can be reliably distinguished 1 ) in seropositive cases by indirect immunoflrouescence ( iif ) testing on salt lamina lucida split skin , 2 ) in research studies by direct immunoelectron microscopy and 3 ) in patients with circulating autoantibodies , by immunoblotting ( ib ) western studies .
the use of these methods is limited by their availability and expense , and the requirement for circulating autoantibodies . in our case , following initial direct immunofluorescence of the biopsy specimen , additional salt split skin studies utilizing 1.0 mol / l sodium chloride were performed . in eba ,
the igg linear bmz deposits classically appear on the dermal side of a split specimen ; in bp , predominantly or exclusively in the epidermal side . in our case , the salt split skin pattern favored the diagnosis of bp , with the additional features of ige and fibrinogen also present on both sides of the nacl induced blister .
other differential diagnoses we considered included bullous impetigo , and a bullous arthropod bite reaction .
in general , patient encounters with biting or stinging arthropods elicit localized reactions including pruritic macules , urticarial wheals and papular reactions .
less frequently , localized bullous or hemorrhagic or disseminated papular reactions may be seen , particularly in children and immunologically naive adults . with the exclusion of bee and wasp venom allergies , immediate - type allergic reactions to arthropod stings and bites
thus , we considered a bullous arthropod bite reaction in our differential diagnosis , which could produce late - phase reactions including the development of sustained edema , vesicles , blisters , and/or intense pruritus .
although igg represents the most commonly documented immunoglobulin subclass in bp patients , several recent reports also highlight the importance of ige ; its binding in the skin triggers complement activation , and further accumulation of inflammatory cells[79 ] .
indeed , a correlation of ige autoantibody with bp180 in a severe form of bullous pemphigoid has been described .
the case demonstrated positivity with igg , ige , fibrinogen and complement / c3 against not only the bmz , but also to dermal nerves , blood vessels and sweat glands .
the desmosomes are multi - protein complexes , promoting stable adhesion of epithelial cells to the underlying extracellular matrix .
interactions between different hemidesmosomal components with each other have been studied ; these interactions have been studied utilizing double hybrid and cell transfection assays .
the results demonstrated that : bp180 binds not only to bp230 , but also to plectin .
the interactions between these proteins are facilitated by the y subdomain within the n - terminal plakin domains of bp230 and plectin , and residues 145 - 230 of the cytoplasmic domain of bp180 .
relative to residues 145 - 230 , different , but overlapping , sequences on bp180 mediate binding to integrin 4 which , in turn , also associates with bp180 via its third fibronectin type iii repeat .
further , sequences in the n - terminal extremity of bp230 mediate its binding to integrin 4 , which requires the c - terminal end of the connecting segment ( up to the fourth fibronectin repeat of the integrin 4 subunit ) .
based on this knowledge , we speculate that , given our patient 's immunofluorescence positivity against the dermal sweat glands , possible epitope spreading between the bp180 and bp230 antigens could elicit reactivity to integrins and/or plectins expressed not only in multiple areas of the bmz , but also in the dermal nerves , sweat glands and/or microvasculature .
in addition , serum from a patient with bullous pemphigoid was recently associated with neurological diseases , recognizing bp antigen in the skin and in the brain .
we were able to demonstrate a direct correlation of our dif and iif / salt split skin positivity with positive pas staining .
relative to patients who live in areas where dif and iif are not available , the pas stain often shows a high correlation with the positivity of immunoglobulins and complement in autoimmune diseases , as shown in our case[1517 ] .
the reaction of periodic acid selectively oxidizes glucose residues , creating aldehydes ; these then react with the schiff reagent , yielding a purple - magenta color .
thus , pas staining is often utilized for staining structures containing a high proportion of carbohydrate macromolecules ( i.e. , glycogen , glycoproteins , or proteoglycans ) , typically found in neutrophils , fungal organisms and basal laminae .
positive pas staining may be found in diverse autoimmune diseases , including vasculitides , autoimmune bullous diseases , autoimmune nephritis and goodpasture 's syndrome[1517 ] .
finally , the significance in our case of abundant cd45 positive lymphocytes around the dermal sweat glands , sweat ducts and neurovascular packages remains unknown .
further investigation of our case features of 1 ) bp ige / igg / fibrinogen linear deposits at the bmz , 2 ) auto - reactivity to dermal sweat glands and nerves and 3 ) cd45 positive infiltrating dermal lymphocytes may lead to a better understanding of this disease .
Output:
| context : bullous pemphigoid ( bp ) , the most common autoimmune blistering disease , is mediated by autoantibodies .
bp primarily affects the elderly and is characterized by the development of urticarial plaques surmounted by subepidermal blisters , and the deposition of immunoglobulins and complement at the basement membrane zone ( bmz ) of the skin .
bp is immunologically characterized by the development of autoantibodies targeting two structural proteins of the hemidesmosomes , bp180 ( collagen xvii ) and bp230 ( bpag1).case report : a 63 -year - old caucasian female patient was evaluated for a 4 day history of several itching , erythematous blisters on her extremities .
biopsies for hematoxylin and eosin ( h&e ) examination , as well as periodic acid - schiff ( pas ) , immunohistochemistry ( ihc ) and direct immunofluorescence ( dif ) analysis were performed.results:h&e demonstrated a subepidermal blister , with partial re - epithelialization of the blister floor . within the blister lumen ,
numerous neutrophils were present , with occasional eosinophils and lymphocytes also noted . within the dermis ,
a mild , superficial , perivascular and periadnexal infiltrate of lymphocytes , histiocytes and occasional eosinophils was identified , with mild perivascular leukocytoclastic debris .
the pas stain was positive at the bmz , and around selected blood vessels , nerves and sweat glands .
dif revealed linear deposits of igg and complement / c3 and fibrinogen at the bmz , and around selected dermal nerves , blood vessels and sweat glands .
strong granular deposits of ige were also observed , colocalizing with monoclonal antibodies to collagen iv ( civ ) . by ihc ,
positive cd45 staining of lymphocytes was seen surrounding selected dermal blood vessels , eccrine sweat glands , and nerves.conclusion:the patient displayed igg , ige , and fibrinogen autoantibodies against the bmz , as well as around some dermal nerves and sweat glands ; their binding in the skin could trigger complement activation .
in addition , the role of the dermal cd45 positive lymphocytes warrants further investigation . |
PubmedSumm6568 | ***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 part of the aging process involves a decline in cellular housekeeping functions disturbing the maintenance of organism homeostasis [ 1 , 2 ] .
the accumulation of damaged and defective components increases cellular stress , for example , oxidative stress , which activates cellular defence mechanisms including nf-b signaling pathway and innate immunity system , such as inflammasomes [ 35 ] ( section 3.1 ) .
aging is associated with a low - grade proinflammatory phenotype which further interferes with housekeeping and cellular homeostasis .
recent studies have indicated that autophagy is a crucial cleansing system preventing inflammation but its capacity clearly declines with aging [ 68 ] .
the nf-b signaling system and the autophagic degradation pathway have been closely conserved during evolution and emerging studies indicate that these systems have many context - dependent interactions with each other .
we will review the recent literature on the control mechanisms of autophagy by nf-b signaling and particularly we will focus on its context - dependent regulation during the aging process . by definition , autophagy or autophagocytosis
is a cellular self - digestion process involving the uptake of cellular components and organelles for degradation by lysosomal system .
the hallmark of autophagy is the appearance of autophagosomes which subsequently fuse with primary lysosomes to form autolysosomes where the ingested material is digested by lysosomal enzymes .
there also exist microautophagy and chaperone - mediated autophagy which deliver cytoplasmic material directly into the lysosomes without the formation of autophagosome .
several reviews have detailed the mechanisms involved in autophagosome formation , for example , over thirty autophagy - related ( atg ) proteins are known to participate in this process [ 911 ] .
beclin 1 and its interactome , that is , proteins interacting with beclin 1 , have a crucial role in the vesicle nucleation during autophagosome formation [ 12 , 13 ] .
beclin 1 and hvps34 , a class iii phosphatidylinositol-3 kinase , assemble the core complex which then cooperates with several stable and transient binding partners in order to establish phagophore formation .
autophagosomes most likely originate in the specialized subdomains of endoplasmic reticulum but in addition , golgi complex and endosomes seem to supply some lipids and proteins to elongating autophagosome membranes .
atg14l protein targets beclin 1/hvps34 complex to the cup - shaped protrusion of the endoplasmic reticulum , called omegasome .
beclin 1 is a bh3-only protein which can interact with the antiapoptotic bcl-2 and bcl - xl proteins which inhibit the autophagosome formation in the initiation phase .
however , bcl-2/xl proteins can be phosphorylated by jnk1 , induced by , for example , starvation and ceramides , which block its inhibitory binding to beclin 1 [ 13 , 16 ] . moreover , competitive binding of bcl-2/xl to other bh3-only proteins , such as bnip3 and bad , also prevents beclin 1 inhibition and induces autophagy [ 13 , 17 ] .
interactions between beclin 1 and antiapoptotic bcl-2/xl proteins are known to regulate the crosstalk between autophagy and apoptosis .
another important regulatory complex in addition to beclin 1 is the ulk1/2 complex which is controlled by mtor kinase [ 10 , 19 ] .
there are several extensive reviews on the regulation of autophagy and its physiological and pathological functions [ 1922 ] .
nf-b signaling pathway is involved in the regulation of multiple cellular functions , for example , apoptosis , autophagy , cellular proliferation , differentiation , metabolism , and adaptive and innate immunity responses .
( i ) the ikk kinase complex including ikk , ikk , and ikk ( also called nemo ) are upstream activators of nf-b signaling , ( ii ) the nf-b / rel dna - binding complexes involving the nf-b proteins p50 and p52 and the rel family members ( rela / p65 , relb , and c - rel ) , and ( iii ) several typical and atypical inhibitory ib proteins ( ib , ib , ib , ib , ib , ibns , bcl-3 , p100 , and p105 ) [ 2325 ] .
briefly , the homo- and heterodimers of nf-b / rel components assemble inactive complexes with ib proteins in the cytoplasm .
after stimulation by upstream kinases , ikk/ kinases phosphorylate ib proteins which are subsequently ubiquitinated and degraded in proteasomes . afterwards , dissociated nf-b / rel dimers translocate to nuclei where they transactivate the expression of hundreds of genes .
this is the basic principle of nf-b function but the nf-b pathway can be controlled at several levels which means that nf-b signaling is a highly context - dependent process .
recently , tieri et al . applied a network analysis to reveal the interactome map of nf-b signaling pathway .
they observed that the integrated network affecting nf-b activation consisted of 622 proteins whereas the nf-b signaling was able to regulate the expression of 426 proteins of which 49 proteins established a feedback loop controlling nf-b activity .
many of the upstream signaling pathways converging in the regulation of ikk complex and directly nf-b components have been characterized [ 2729 ] .
the upstream pathways were earlier classified into canonical and noncanonical pathways but currently , it seems that this scenario is not adequate due to intense crosstalk between different signaling pathways .
moreover , ikk complex has many nf-b - independent , context - dependent functions , for example , in immunity and cancer .
thus , modifications such as phosphorylation , acetylation , methylation , sulfhydration , sumoylation , and ubiquitination can regulate the duration and capacity of transactivation and possibly also the dimerization of nf-b / rel components and their recruitment of proper coregulators to specific dna sites [ 3133 ] .
context - dependent factors affect the specificity which links different stimuli to the activation of relevant nf-b - driven target genes .
it is most likely that context - dependent factors control the responses of nf-b signaling with respect to apoptosis , autophagy , and activation of inflammation .
there is a substantial literature indicating that nf-b signaling and autophagy are reciprocally involved in the control of cellular survival and any dysfunction in this crosstalk can evoke detrimental effects .
for instance , it is known that a decline in autophagy can stimulate nf-b - dependent inflammatory responses whereas an increase in autophagy can prevent inflammatory responses . on the other hand , the inhibitors of nf-b signaling are effective activators of autophagocytosis , for example , ampk and sirt1 signaling [ 38 , 39 ]
. however , there is mounting evidence that nf-b signaling can either activate or inhibit autophagocytosis in a context - dependent manner ( see below ) .
moreover , several proteins , for example , bcl-2 family members are key players both in the regulation of autophagy and apoptosis indicating that there could be a context - dependent crosstalk via the activation of ikk - nf-b signaling axis .
recently , trocoli and djavaheri - mergny reviewed the complex interplay between nf-b signaling and autophagy in cancer formation .
were the first investigators who demonstrated that several autophagic inducers stimulated autophagy via the activation of the ikk complex but without any involvement of nf-b signaling in several cell lines .
they also observed that starvation and rapamycin did not induce autophagy in the livers of mice carrying a conditional knockout of ikk. they did not reveal any exact mechanism but they noted that the ikk complex promoted autophagy by ( i ) activating ampk , ( ii ) inhibiting mtor , and ( iii ) depleting nuclear p53 , all of which are crucial inducers of autophagy . on the other hand , comb et al . demonstrated that cellular starvation induced the expression of atg5 , becn1 , and lc3 , important autophagy genes , in the ikk and ikk-dependent manner but independently of nf-b signaling .
interestingly , starvation stimulated the expression of nf-b - dependent antiapoptotic genes , for example , bnip3 and ciap2 .
these studies indicate that in some circumstances , ib kinases can stimulate canonical autophagy and induce the expression of autophagy - related genes without nf-b transcription factors ( figure 1 ) .
. revealed that the regulatory subunit of pi3k , p85 , is an ikk phosphorylation target in cellular starvation inducing the transient feedback inhibition of pi3k / akt signaling and subsequently triggering autophagy via the inhibition of mtor activity .
it is important to emphasize here that the autophagy activated by the ikk complex in acute stress , extending up to some hours , was transient , probably due to the effective feedback inhibition .
chaperone is a major stability factor for the activation of ikk signalosome [ 4446 ] .
it is known that acute cellular stress can trigger the dissociation of hsp90 from the ikk complex which inhibits nf-b signaling [ 46 , 47 ] .
demonstrated that the treatment of cells with geldanamycin , an inhibitor of hsp90 , induced the degradation of ikk and ikk proteins via autophagy and neither ubiquitination nor proteasomes were involved in the degradation of the ikk complex .
moreover , they also revealed that geldanamycin stimulated the autophagic degradation of nik , a key kinase activating ikk in the noncanonical nf-b pathway .
these studies indicate that hsp90 has a crucial role in the control of signaling via the ikk - nf-b axis , that is , acute insults trigger ikk - mediated autophagy and block nf-b - driven transcription whereas prolonging the stress will stimulate the autophagic degradation of the ikk complex , thus , preventing apoptotic cell death .
observed that the excessive activation of ikk could trigger its monoubiquitination by ro52 , an e3 ubiquitin ligase , which subsequently enhanced the autophagic degradation of ikk ( figure 1 ) .
moreover , keap1 , another e3 ligase , can interact with ikk , but not with ikk , and thus induce the autophagic degradation of ikk which consequently inhibits nf-b signaling . in conclusion
, it seems that the ikk complex and autophagy have a mutual function in acute cellular stress , that is , at its onset , ikk - induced autophagy ensures the energy supply and supports housekeeping but later , autophagic degradation of the ikk complex prevents the excessive activation of ikks and their harmful responses , such as tumorigenesis and inflammation ( figure 1 ) .
there is an interesting context - dependent activation of autophagy between the ikk complex and its downstream target , the nf-b system .
occasionally , the ikk complex can trigger autophagy without involvement of nf-b system ( section 2.1 . )
whereas under other circumstances , nf-b is a crucial inducer of autophagy . for instance , nivon et al
. demonstrated that nf-b signaling triggered autophagy during the heat shock recovery period and thus supported cellular survival .
inhibition of nf-b activation blocked the autophagic response and augmented cell death after a heat shock stress .
recently , they revealed that the nf-b signaling induced by heat stress increased the expression level of bag3-hspb8 complexes which enhanced the autophagic uptake and elevated the clearance of irreversibly damaged proteins .
this implies that nf-b signaling has an important role in the maintenance of protein quality during heat shock .
excessive heat shock can also induce an atypical activation of nf-b signaling through a thermolabile dissociation of the nf-b complex without any phosphorylation of ib proteins and thus no involvement of the ikk signalosome is necessary .
demonstrated that the p65/rela component can induce the transcription of the becn1 gene ( beclin 1 ) and thus stimulate autophagy in t - cells .
they identified some conserved nf-b binding sites both in the promoter and the first intron of the becn1 gene in mice and humans .
observed that p65 regulated beclin 1 expression in several cell types and consistently enhanced the induction of autophagy .
their study indicated that the becn1 gene is one of the target genes of nf-b signaling .
bhatnagar et al . revealed that the proinflammatory cytokine tweak , a well - known nf-b - dependent inducer of atrophy in skeletal muscles , could stimulate the expression of several autophagy genes , for example , becn1 , lc3b , atg5 , in c2c12 myotubes and it also activated autophagocytosis .
it is known that tweak can stimulate nf-b signaling via traf6 and induce a prolonged activation of nf-b .
traf6 , an e3 ubiquitin ligase , can also ubiquitinate beclin 1 in bh3 domain and trigger autophagy .
it seems that nf-b signaling can directly stimulate the expression of autophagy - related genes in order to support cell survival but also organismal life since skeletal muscle atrophy supplies amino acids , for example , in starvation ( figure 1 ) .
jiang et al . revealed that the downregulation of hsp90 expression by selenite inhibited the signaling of the ikk / nf-b pathway and significantly reduced the expression of beclin 1 which subsequently increased the transition from autophagy to apoptosis .
recently , romano et al . observed that ionizing radiation stimulated nf-b signaling via the activation of fkbp51 in malignant melanoma cells .
subsequently , the activation of nf-b protected from apoptotic cell death by inducing xiap expression and promoting bax degradation by autophagy .
these studies indicate that nf-b - dependent autophagy can prevent apoptotic cell death . however , there are several reports which have demonstrated that the nf-b - dependent activation of autophagy could lead to autophagic cell death [ 6365 ] . currently , it is a matter of debate whether autophagy can be the mechanism of cell death .
there are many observations which indicate that under certain circumstances the nf-b system can also mediate the suppression of autophagy .
for instance , djavaheri - mergny et al . observed that nf-b signaling inhibited the autophagy induced by tnf- in different cell types .
they revealed that nf-b signaling activated mtor kinase which is the major inhibitor of autophagy .
moreover , suppression of nf-b signaling in this model stimulated the expression of beclin 1 and subsequently triggered autophagy in tnf--treated cells .
this response was mediated by ros which can context - dependently promote autophagocytosis . upon tnf- treatment ,
the activation of ikk/ can repress tsc complex [ 69 , 70 ] , a potent inhibitor of mtor , and thus induce the activation of autophagy . on the other hand
, nf-b signaling , induced by tnf- , can inhibit the expression of pten , a dual - specificity phosphatase that inhibits insulin / akt pathway [ 71 , 72 ] .
the insulin / akt pathway is a potent activator of mtor and thus nf-b signaling can inhibit autophagy by stimulating this homeostatic pathway ( figure 1 ) . interestingly , signaling via insulin / igf pathway can accelerate the aging process .
. demonstrated that the prolonged activation of nf-b signaling inhibited the expression of becn1 and atg5 genes and repressed autophagy in macrophages .
interestingly , it seems that the activation of nf-b signaling in acute stress can provoke autophagy ( section 2.2 ) whereas a delayed activation can suppress autophagy .
probably , this is a feedback regulation which could prevent cells from autophagic cell death .
it is known that nf-b signaling can control the expression of several , well - known activators and inhibitors of autophagy and in that way indirectly and context - dependently regulate autophagy ( figure 1 ) .
beclin 1 network is a crucial regulator of autophagocytosis but also apoptosis [ 13 , 18 , 75 ] .
( bcl-2-homology-3 ) , ecd ( evolutionarily conserved domain ) and ccd ( coiled - coil domain ) through which it binds a number of proteins to create a functional network called the beclin 1 interactome .
for instance , beclin 1 binds with bcl-2 and bcl - xl , which are the major antiapoptotic proteins and thus the beclin 1 interactome can control both autophagy and apoptosis ( figure 2 ) .
binding of bcl-2 and bcl - xl to beclin 1 protein inhibits the formation of the initiation complex and subsequently blocks autophagocytosis .
however , the phosphorylation of bcl-2 by jnk1 and beclin 1 by dapk can dissociate the interaction between beclin 1 and bcl-2/xl which supports autophagocytosis .
the versatile balance between the proteins binding to bcl-2/xl and beclin 1 controls the activity of autophagy .
for instance , the overexpression of bcl - xl delays the onset of autophagy whereas downregulation of bcl-2 stimulates autophagy .
interestingly , it is known well that nf-b signaling is a potent inducer of bcl-2 and bcl - xl transcription [ 7983 ] and thus the expression of bcl-2/xl inhibits apoptosis but simultaneously it also represses autophagy .
moreover , nf-b signaling stimulates the transcription of bfl-1/a1 , a bcl-2 family member and a beclin 1 binding partner , which also negatively regulates autophagy [ 84 , 85 ] .
recently , chang et al . characterized the bcl-2-interacting protein naf-1 ( nutrient - deprivation autophagy factor-1 ) in endoplasmic reticulum , which is required for the interaction between beclin 1 and bcl-2 .
it is known that bcl-2 inhibits the beclin 1-mediated autophagy only if it is present in er . chang et al .
demonstrated that naf-1 also interacted with ip3 receptor and mediated the bcl-2-induced regulation of er calcium homeostasis .
there are also reports indicating that the overexpression of bcl-2 could activate nf-b signaling via the mekk-1/ikk pathway [ 87 , 88 ] .
. in conclusion , there is mounting evidence indicating that nf-b signaling can induce autophagy by inducing the transcription of autophagy genes ( section 2.2 ) but on the other hand , it can repress autophagy by stimulating the expression of antiapoptotic , bcl-2 family genes .
it seems that nf-b signaling controls the crosstalk between autophagy and apoptosis in a context - dependent manner .
shi and kehrl demonstrated that lps as well as many other stimuli of autophagy in murine macrophages , for example , il-1 , ifn , and amino acid starvation , induced lys-117 ubiquitination of beclin 1 .
they observed that traf6 was able to bind to beclin 1 and it triggered a k63-linked ubiquitination at the bh3 site of beclin 1 protein .
they also revealed that ubiquitination facilitated the oligomerization of beclin 1 and thus enhanced autophagy , probably preventing the formation of inhibitory complexes between bcl-2/xl and beclin 1 .
shi and kehrl also observed that a20 , a ubiquitin - editing enzyme , provoked the deubiquitination of beclin 1 and in that way inhibited autophagic capacity of beclin 1 .
interestingly , a20 deubiquitinase is a target gene of nf-b transactivation but on the other hand , the expression of a20 establishes a negative feedback mechanism to shut down the activation of nf-b system [ 91 , 92 ] .
the activation of the nf-b signaling pathway , for example , by tnf and il-1 receptors , involves several regulatory steps mediated by k63 ubiquitination at the level of upstream kinases and inhibitory ib proteins [ 89 , 91 ] .
a20 is a well - known inhibitor of nf-b - mediated inflammatory responses occurring in crohn 's disease , rheumatoid arthritis , and psoriasis .
it seems that a20 and its coactivator abin-1 could be potent inhibitors of beclin 1 function enhancing its deubiquitination and thus supporting its complex formation with bcl-2/xl proteins during the chronic inflammation . recently , jounai et al
. observed that beclin 1 can interact with the members of nlr family of inflammasome receptors , for example , nlrc4 , nlrp3 , nlrp4 , and nlrp10 .
they revealed that the evolutionarily conserved domain ( ecd ) of beclin 1 could physically bind to the nacht domain of nlr proteins .
. also revealed that nlrp4 and nlrc4 inhibited the autophagosome formation whereas nlrp4 could also repress the maturation of autophagosomes to autolysosomes .
nlr proteins are important intracellular danger sensors assembling inflammasomes which in turn activate inflammatory caspases to cleave the proforms of il-1 and il-18 into the mature , secreted cytokines [ 4 , 96 ] .
. demonstrated that the activation of inflammasomes was dependent on the priming phase in which nf-b signaling induced the expression of nlrp3 and the proforms of il-1 and il-18 in order to assemble inflammasomes .
currently , it is not known whether other nlr receptors require the priming stage to facilitate inflammasome activation
. however , it seems that inflammasome receptors can bind to beclin 1 and thus repress autophagy . on the other hand , shi et al
. demonstrated that the activation of autophagy by inflammatory signals induced the ubiquitination of asc adapter of inflammasomes and subsequently triggered their degradation via p62-mediated selective autophagy .
this indicates that autophagy can repress the overwhelming inflammation and imply that a decline in autophagic capacity can generate chronic inflammatory conditions both during aging process and age - related diseases ( section 3 ) .
there are also reports that antiapoptotic proteins bcl-2/xl could bind to nlrp1 protein and thus inhibit its inflammasome function [ 99 , 100 ] .
these observations imply that antiapoptotic proteins bcl-2/xl can also regulate inflammation , in addition to autophagocytosis .
there is a substantial literature indicating that ros and oxidative stress can control autophagocytosis [ 68 , 101 , 102 ] .
moreover , inducible nitric oxide synthase ( inos ) , induced by nf-b activation , stimulates the production of nitric oxide ( no ) which has a crucial role as a messenger molecule but its dysfunction generates nitrosative stress and provokes many diseases .
recently , sarkar et al . demonstrated that no could inhibit autophagy by s - nitrosylating and thus inhibiting the activities of ikk and jnk1 , potent inducers of autophagy .
the inhibition of jnk1 by no reduces the phosphorylation of bcl-2 and in that way increases the formation of inhibitory bcl-2/beclin 1 complexes .
the s - nitrosylation of ikk reduces its capacity to activate ampk , an important inducer of autophagy by activating ulk1 and repressing mtor .
these studies indicate that cellular stress can repress autophagy via the reactive nitrogen species induced by nf-b signaling .
the interactome of beclin 1 contains several binding factors , for example , bcl-2 and bcl - xl ( section 2.3.1 ) , but the beclin 1 complexes can be disrupted by bh3 domain containing proteins , for example , bnip3 and nix / bnip3l , which bind to bcl-2 and bcl - xl proteins and subsequently activate the formation of the beclin 1/hvps34/hvps15 interaction , an initiation complex in the process of autophagocytosis .
hypoxia is a potent inducer of bnip3 and nix expression which in particular , enhances the autophagic uptake of mitochondria , a process called mitophagy .
it is known that bnip3 and nix represent a survival mechanism in moderate stress but excessive insults contribute to mitochondrial damage and consequently to cell death through the induction of apoptosis , for example , in the hypoxic myocardium [ 106 , 107 ] .
several transcription factors regulate the transcription of bnip3 gene , for example , hif-1 , nf-b , e2f1 , foxo3 , p53 , and sp1 [ 107109 ] .
moreover , the promoter of bnip3 contains several gc - rich regions and is hypermethylated and silenced in many cancers .
kirshenbaum and coworkers demonstrated that the binding of p65 component of the nf-b complex induced the transcriptional repression of bnip3 expression in rat ventricular myocytes [ 109111 ] ( figure 2 ) . under physiological conditions , the nf-b
complex interacts with hdac1 , histone deacetylase 1 , and prevents the binding of e2f1 to the adjacent sites in bnip3 promoter . in hypoxic conditions or during the deficiency of nf-b , binding of e2f1 , hif-1 , and foxo3 factors stimulate autophagy which can lead to cell death . moreover , p53 can also suppress the expression of bnip3 by binding to the bnip3 promoter and recruiting the corepressor sin3a .
these studies indicated that the expression level of bnip3 is a crucial regulator of autophagy through beclin 1 interactome .
wei et al . demonstrated that starvation triggered the phosphorylation of bcl-2 at several residues and induced its dissociation from beclin 1 which provoked autophagocytosis .
many other stress - related factors can also activate autophagy through the jnk1 pathway , stimulating the dissociation of bcl-2/beclin 1 complex , for example , ceramides .
there is substantial evidence that nf-b signaling suppresses the jnk1 signaling cascade and thus can protect cells from jnk1-induced apoptosis [ 114117 ] .
several studies have indicated that nf-b signaling can induce the expression of antioxidants and antiapoptotic proteins which prevent the prolonged activation of jnk1 signaling for example , during the tnf- exposure .
for instance , nf-b signaling stimulates the expression of gadd45 which inhibits the activity of mkk7 , an upstream kinase of jnk1 .
moreover , a20 and xiap , which are also induced by nf-b , inhibit the tnf--mediated jnk1 activation [ 115 , 116 ] .
it is well known that ros and redox signaling can increase autophagocytosis via many different mechanisms , in addition to jnk1 regulation [ 68 , 101 , 102 ] .
for instance , ros can oxidize cysteine - rich domains of atg4 and rubicon and thus enhance autophagy [ 68 , 102 ] .
. demonstrated that ros can activate type iii pi3 kinase , also known as hvsp34 which is a beclin 1-interacting protein and the major enhancer of autophagy .
regulation of antioxidant gene expression is one of the major functions of nf-b signaling and thus nf-b activity can repress autophagy by reducing the presence of ros although in many contexts it can protect cells from injuries induced by excessive ros production .
there are several aspects indicating that autophagy is a tumor suppressor mechanism , for example , beclin 1 is a haploinsufficient tumor suppressor protein , and chronic inhibition of autophagy can increase carcinogenesis [ 120 , 121 ] . moreover , p53 can have both activating and inhibiting effects on autophagy , that is , nuclear p53 stimulates autophagy but in cytoplasm , p53 represses autophagy [ 120 , 122 ] . on the other hand , there is mounting evidence pointing out that nf-b signaling can induce tumorigenesis , either directly or via inflammation . whether or not this is linked to the capacity of nf-b to repress
nuclear p53 is a potent inducer of autophagy since it can transactivate many activators of autophagy , for example , dram1 , dapk-1 and sesn2 .
however , the exact mechanism by how nf-b - dependent signaling could inhibit the transcriptional activity of p53 is not known . in conclusion
, there is substantial literature which shows that nf-b signaling can either stimulate or inhibit autophagocytosis .
it is clear that the control of autophagy by nf-b system is a context - dependent process which is closely linked together apoptosis and autophagy .
it seems that nf-b signaling , which is a potent antiapoptotic factor and inducer of inflammatory defence , could also have harmful consequences by inhibiting autophagocytosis .
during the last decade , mounting evidence has revealed that there is a clear imbalance between adaptive and innate immunity in mammals during the aging process [ 126 , 127 ] .
immunosenescence of adaptive immunity system enhances the activation of innate immunity responses which generates a proinflammatory phenotype , called inflammaging .
the major characteristics of inflammaging are the increased expression of genes associated with inflammation in tissues [ 128 , 129 ] and augmented levels of cytokines , for example , il-6 and tnf- , in serum [ 130 , 131 ] .
these observations agree with earlier studies indicating that the nf-b system is activated with aging in many tissues [ 132135 ] .
interestingly , inflammaging is also linked to a clear decline in autophagy [ 68 , 136 ] as well as apoptosis [ 137141 ] .
moreover , it seems that the aging process in vivo also involves the appearance of senescent cells which are resistant to apoptotic cell death [ 142145 ] .
have revealed that cellular senescence is linked to a proinflammatory phenotype called the senescence - associated secretory phenotype ( sasp ) .
recent studies have indicated that the formation of this condition is stimulated by the activation of nf-b signaling .
kang et al . demonstrated that impairment of autophagy induces a premature senescence in normal human fibroblasts and on the other hand , replicatively senescent cells expressed reduced levels of autophagy proteins .
however , autophagy can facilitate oncogene - induced senescence and trigger autophagic cell death by increasing the expression of noxa which is able to displace bcl-2 family members from the beclin 1 complex .
impaired autophagy supports the accumulation of waste materials into cells , called the garbage - can hypothesis by brunk and terman .
recent studies have indicated that the decline in autophagy and impaired housekeeping can stimulate nf-b signaling and generate chronic inflammation via the activation of inflammasomes [ 4 , 5 , 152 ] . in particular , oxidative stress , which increases with aging ,
. indicated that autophagy could be transcriptionally downregulated during normal aging process in the human brain .
their study also revealed that aging could decrease the activity of type iii pi3k ( hvps35 ) , which is a crucial factor of beclin 1 interactome during the nucleation phase of autophagy .
protein - protein interaction analysis revealed that rip1 and pkc kinases and p62/sequestosome could be involved in the regulation of autophagy with aging .
all of these three proteins are associated with nf-b signaling and autophagy [ 154156 ] .
hua et al . observed a significant decrease in the protein levels of beclin 1 and atg5 whereas that of insoluble p62 was elevated , probably indicating its binding to protein aggregates in the hearts of old mice .
moreover , aging decreased the activity of ampk whereas mtor activity was increased , both of these changes could reduce autophagic activity .
wohlgemuth et al . reported that the protein levels of atg7 , atg9 , and lamp1 decreased but that of beclin 1 was unaffected in old rat hearts .
in general , these studies indicate that the expression of several autophagy proteins seems to be decreased during organismal aging as well as under cellular senescence in vitro conditions .
however , the changes are small and tissue - specific and not repeatable in different studies which implies that many other factors in addition to the expression level can contribute to the decline in the autophagic process in conjunction with aging .
the regulation of the beclin 1 interactome is a crucial control mechanism in the initiation of autophagy [ 13 , 18 ] .
as described earlier ( section 2.3.1 ) , transcription factor nf-b is an important transactivator of beclin 1 itself as well as of several other binding partners , for example , bcl-2 , bcl - xl , and nlrp4 .
normally , beclin 1 protein is complexed with bcl-2/xl and autophagy is inhibited but the balance is dynamic and can be controlled by the availability of the different binding partners .
many reports have demonstrated that aging is linked to an increase in the expression of antiapoptotic bcl-2 and bcl - xl proteins , in particular in brain [ 159 , 160 ] . moreover , satou et al . observed that the immunoreactivity of bcl-2 protein within neurons increased with the severity of alzheimer 's disease .
it also seems that oxidative stress and accumulation of lipofuscin could enhance the expression of bcl-2 in neurons with aging [ 159 , 160 ] .
xu et al . demonstrated that the intracerebroventricular injection of proinflammatory cytokines , tnf- and ifn , markedly increased the expression of bcl-2 in neurons of cortex and hippocampus .
interestingly , the response was age - related being clearly more prominent in the brains of old mice .
this implies that inflammation , probably via the stimulation of nf-b signaling , is a significant contributor to the decline of apoptosis and autophagy during aging .
several studies have revealed that the expression of bcl-2/xl proteins is clearly increased in senescent cells in vitro , simultaneously with the augmentation of apoptosis resistance [ 145 , 163 ] .
wang observed that serum deprivation reduced the level of bcl-2 in young , proliferating human fibroblasts whereas in senescent cells , the expression level of bcl-2 remained unchanged .
this agrees with the observations that the capacity for autophagy is impaired in human senescent fibroblasts .
moreover , the overexpression of bcl-2 reduces the lifespan of cultured human fibroblasts as well as induces cellular senescence in human carcinoma cells .
. demonstrated that the inhibition of jnk1 activity and subsequently the reduction in the level of bcl-2 phosphorylation , the signal for autophagy ( section 2.3.1 ) , induced cellular senescence both in human fibroblasts and carcinoma cells .
this indicates that the autophagy via jnk / bcl-2 phosphorylation is essential in the prevention of cellular senescence .
these studies imply that bcl-2/xl proteins have a crucial role with aging in the decline of apoptotic capacity as well as autophagy via the stabilization of beclin 1 complexes .
in view of the important function of nf-b signaling in the generation of cellular senescence , it seems plausible that the overexpression of bcl-2/xl has a major role in the appearance of the senescent phenotype . a decline in autophagy with aging
can also increase ros production and stimulate the expression of inflammasome components via nf-b signaling ( section 2.3.1 ) .
interestingly , many of the inflammasome receptors can interact with beclin 1 , for example , nlrc4 , nlrp3 and nlrp4 , and inhibit autophagocytosis .
the beclin 1 interactome also contains hmgb1 proteins , enigmatic proteins which can regulate ( i ) genome function in nuclei , ( ii ) nf-b transactivation , ( iii ) autophagy in cytoplasm , and ( iv ) inflammatory responses in extracellular space [ 167170 ] .
tang et al . demonstrated that hmgb1 could directly bind to beclin 1 which displaced the inhibitory bcl-2 protein from the complex and subsequently activated autophagy .
hmgb1 is evolutionarily conserved and contains sequence homology with beclin 1 which implies that it controls autophagocytosis .
ros and oxidative stress oxidize the cysteine residues of hmgb1 which is required for the cytoplasmic translocation of hmgb1 and its binding to beclin 1 and the subsequent stimulation of autophagy . on the other hand ,
the activation of nlrp3 inflammasomes triggers the secretion of hmgb1 protein into the extracellular space where it can bind several immune receptors and thus stimulate inflammatory responses .
hmgb1 is an architectural factor in genome , for example , assisting in the binding of nf-b complexes to dna .
there are age - related , tissue - specific changes in the expression of nuclear hmgb1 ( previously called hmg-1 ) , for example , the level of hmgb1 clearly decreases in brain ( neurons ) , heart , lung , and thymus [ 173 , 174 ] .
in contrast , the overexpression of hmgb1 is one of the hallmarks of cancer . in this scenario
, it seems that autophagy and inflammation are evolutionarily linked to each other to defend the host organism . in 1956 , harman presented the free radical theory of aging which states that oxygenderived free radicals attack cellular constituents causing structural damage and impairing housekeeping functions .
this theory has received substantial support since it was appreciated that the level of ros - induced damage augments with aging .
however , ros are signaling molecules , for example , stimulating autophagy ( section 2.3.2 ) and it is known that the enhancement of autophagy increases the lifespan [ 136 , 177 ] .
have proposed a gradual ros response hypothesis , which maintains that low ros levels activate signaling pathways which protect cells against different insults .
however , with increases in the duration and input of stress , the accumulation of ros could become detrimental and induce toxic responses .
this theory could explain the apparently contradictory evidence that is , that a low level of oxidative stress can extend the lifespan in animal experiments .
recently , morgan and liu reviewed the extensive crosstalk between ros and nf-b signaling .
nf-b signaling induces the expression of major antioxidants , for example , superoxide dismutases , thioredoxins , heme oxygenase , and glutathione peroxidase-1 . on the other hand , nf-b stimulates the expression of many ros - producing enzymes , for example , nadph oxidase-2 , inducible nos , and xanthine oxidase .
ros can also directly control the activity of nf-b signaling in a cell type - specific manner .
moreover , bauernfeind et al . demonstrated that the nf-b - provoked induction of nlrp3 expression , an inhibitory binding partner of beclin 1 ( section 2.3.1 ) , was highly dependent on the presence of ros . in this way
, ros could inhibit the function of beclin 1 initiation complex and thus repress autophagy .
it seems that nf-b signaling has a crucial role in the context - dependent regulation of autophagy .
currently , it is not known whether a low - grade inflammatory state with increased ros levels could generate some feedback responses in the nf-b signaling which might suppress autophagocytosis with aging .
metabolic syndrome is a major age - related disorder involving obesity , hypertension , diabetes , and cardiovascular diseases .
zhang et al . demonstrated that overnutrition , a common cause of metabolic syndrome , activated ikk/nf-b signaling in hypothalamic neurons and caused central insulin and leptin resistance .
further studies have revealed that excessive nutrition and systemic inflammation induced oxidative and endoplasmic stresses and activated nf-b signaling in hypothalamus which subsequently triggered metabolic inflammation and provoked obesity and hypertension [ 182 , 183 ] .
recently , meng and cai demonstrated that the tissue - specific inhibition of autophagy in hypothalamus stimulated ikk/nf-b signaling and induced inflammatory changes which were associated with the development of obesity and systemic insulin resistance .
these studies indicate that the decline in autophagy in hypothalamic neurons can lead to metabolic dysfunctions in many tissues and ultimately induce metabolic syndrome .
transgenic and knockout models have revealed complex , tissue - specific functions of nf-b signaling .
moreover , aging responses are tissue - specific and thus it needs to be clarified whether aging controls the tissue - specific crosstalk between autophagy and nf-b system .
the nf-b signaling system and autophagic degradation pathway are evolutionarily conserved , major cellular survival mechanisms .
it is most likely that they have engaged in a close crosstalk with each other although its detailed characterization has remained elusive .
there is emerging evidence indicating that the reciprocal regulation is highly dependent on the cellular context which emphasizes their fundamental role in host defence .
moreover , it seems that autophagy and apoptosis are controlled in cooperation with certain common regulatory proteins , for example , bcl-2 , bcl - xl and bnip3 .
it is also known that autophagy is an important regulator of inflammatory responses , in particular via the inflammasomes .
recent studies have revealed that the beclin 1 interactome is a key player which controls autophagic initiation but it has also crucial effects on the function of apoptosis and inflammasomes .
interestingly , the nf-b transcription factor directly regulates the transactivation of beclin 1 and many other components of the beclin 1 interactome .
moreover , nf-b signaling controls the level of ros and oxidative stress which are potent activators of autophagy .
one puzzling aspect is that ikk/ , close upstream kinases of nf-b signaling , can in certain contexts stimulate autophagy without any activation of nf-b signaling .
currently , it is not known whether the regulation mechanisms of autophagy , apoptosis , and inflammasomes are linked to each other but clearly they act in concert to aggravate the aging phenotype and expose tissues to the danger of age - related degenerative diseases .
there are some indications that the beclin 1 interactome and increased oxidative stress may be critically involved in the aging process .
several studies have revealed that nf-b signaling is enhanced with aging which could explain the appearance of a low - grade inflammatory phenotype as well as the decline in autophagy and increased apoptosis resistance .
intriguingly , it is likely that the highly chronic nature of the aging process affects the regulation of autophagy by nf-b signaling in a context dependent manner that is , impairing autophagy and inducing a proinflammatory aging phenotype .
Output:
| the nf-b signaling system and the autophagic degradation pathway are crucial cellular survival mechanisms , both being well conserved during evolution .
emerging studies have indicated that the ikk / nf-b signaling axis regulates autophagy in a context - dependent manner .
ikk complex and nf-b can enhance the expression of beclin 1 and other autophagy - related proteins and stimulate autophagy whereas as a feedback response , autophagy can degrade ikk components .
moreover , nf-b signaling activates the expression of autophagy inhibitors ( e.g. , a20 and bcl-2/xl ) and represses the activators of autophagy ( bnip3 , jnk1 , and ros ) .
several studies have indicated that nf-b signaling is enhanced both during aging and cellular senescence , inducing a proinflammatory phenotype .
the aging process is also associated with a decline in autophagic degradation .
it seems that the activity of beclin 1 initiation complex could be impaired with aging , since the expression of beclin 1 decreases as does the activity of type iii pi3k . on the other hand ,
the expression of inhibitory bcl-2/xl proteins increases with aging .
we will review the recent literature on the control mechanisms of autophagy through ikk / nf-b signaling and emphasize that nf-b signaling could be a potent repressor of autophagy with ageing . |
PubmedSumm6569 | ***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: polypropylene ( pp ) is a well - known hydrophobic polymer which has good mechanical properties and easy processing with low cost and excellent recyclability [ 1 , 2 ] . because of its good film and fiber properties
however , in order to obtain a better in vivo biocompatibility , hydrophilic groups can be introduced into this polymer to overcome its hydrophobic character via postpolymerization reactions .these
newly formed polymers are named as amphiphilic block copolymers . grafting reactions of the hydrophilic segments with a hydrophobic chain
can be performed in three routes [ 46 ] : grafting from , grafting through , and grafting onto leading to comb- or brush - type graft copolymers [ 711 ] .
brush - type graft copolymers consist of a linear backbone with a high grafting density of side chains ( usually one side chain per repeat unit of the backbone ) .
comb - type graft polymers consist of a main polymer chain , the backbone with one or more side chains attached to it through covalent bonds , and the branches .
the total molar mass and the properties of comb - type graft are determined by the backbone length , grafting density , and side chain length . grafting onto method of polymerization
block copolymers having a poly(ethylene glycol ) ( peg ) comprise a special and interesting category since peg is a crystalline , neutral , biocompatible material with hydrophilic properties [ 1315 ] .
they have a unique molecular structure containing parts with both hydrophobic and hydrophilic character [ 1618 ] .
since peg overcomes the hydrophobic effect of the pp , the diversity of in vivo application of pp - peg will be expanded . to our knowledge ,
experimental studies concerning the in vivo properties of low and pp - peg block copolymers with high molecular weight have not been studied previously .
another attractive research field in biomaterials is polymer - stabilized nanoparticles , especially metal nanoparticles such as gold and silver [ 1927 ] . in our previous study , we have already pointed out antimicrobial effects of au and ag nanoparticles embedded into the pp - g - peg amphiphilic polymers .
we have also studied the in vivo and in vitro biocompatibility of au - embedded copolymer samples [ 2831 ] .
au - nanoparticle - embedded biodegradable polymers were found to cause less inflammation when compared to pure type .
the synthesis , spectroscopic characterization , and antibacterial activity of metal nanoparticles embedded in the pp - g - peg amphiphilic comb - type graft copolymers were studied by our research group , previously . according to these recent data
, we think that this copolymer can be a promising biomaterial and we have planned a new study based on in vivo behavior of gold - nanoparticle - attached pp - g - peg and pure pp - g - peg film samples .
peg2000 , peg4000 , chlorinated pp ( pp - cl ) , nah , and the solvents were all purchased from aldrich and used without further purification . the synthesis of pp - g - peg2000
, pure pp - g - peg4000 , au - nanoparticles - embedded pp - g - peg2000 , and au - pp - g - peg4000 was explained in our previous study in detail [ 12 , 28 ] .
briefly , the williamson - ether - synthesis - like reaction between peg and pp - cl was performed in thf solution in the presence of sodium hydride .
a typical endcapping reaction was performed as follows : peg-2000 ( 5.0 g , 2.5 mmol ) and pp - cl ( 1.43 g , 1.0 mmol cl ) were mixed and dissolved in dry thf ( 10 ml ) .
nah ( 0.12 g , 5 mmol ) was added to the solution , and the reaction mixture was stirred at room temperature under argon for 3 days .
the reaction mixture was poured into 200 ml water containing 1 ml of concentrated hcl .
the polymer was filtered , washed with distilled water , and dried under vacuum at 50c for a day . for the purification ,
the crude polymer was redissolved in chloroform and reprecipitated in 200 ml of methanol and then dried under vacuum overnight .
gold - nanoparticles - embedded pp - g - peg amphiphilic graft copolymers were obtained in our previous study .
briefly , aqueous stock solutions of haucl4 : 0.1 m and the reducing agent , nabh4 ( 0.1 m ) , were prepared separately .
the pp - g - peg2000 graft copolymer ( 0.2 g ) was dissolved in 20 ml of thf .
0.10 ml of haucl4 aqueous solution was added into the polymer solution by vigorously stirring .
after 10 min stirring , 0.10 ml of nabh4 aqueous solution was added to this mixture , generating a deep red colloidal solution .
the solution was stirred 10 more minutes and then was poured into a petri dish ( = 7 cm ) , and the solvent was allowed to evaporate leaving a deep red colored thin polymer film .
the in vivo implantation process was the same with our previous study of au - nanoparticle - embedded biodegradable polyhydroxyoctanoate ( pho ) polymer blocks .
we have analyzed in vivo behavior of five different polymers , pp as the control group , pp - peg 2000 , pp - peg-4000 , au - embedded pp - peg , and au - embedded pp - peg 4000 .
two polymer film samples of five different polymer types were prepared in standard measures as 10 12 0.3 mm in dimensions , and eight polymer film samples in total were sterilized via ethylene oxide gas for eight hours and implanted to rats in sterile forms .
all surgical procedures were done in sterile conditions under the approval of ethical committee of hacettepe university .
a mixture of 0.1 ml / kg alphasyn and 0.3 ml / kg ketamine was used to anaesthetize five different female albino wister rats in average weight of 250 g. then , two polymer film samples of each type were embedded into the back of five different rats individually .
a 5 cm midline incision was made under an operating microscope ( zeiss , 3,5 * ) .
each side of the spinous process of the vertebrae was dissected bluntly to create a subcutaneous pocket for the placement of the polymer films .
each polymer film sample was anchored to each side of the back via 7,0 nylon sutures ( ethilon , ethicon ) to prevent displacement .
after 30 days of implantation , all five rats were sacrificed and two polymer samples of the same type attached to the subcutaneous tissue and muscle fascia were harvested from each animal .
one polymer sample was kept for sem assessment , and the other block was immediately fixed in a 10 wt% formalin solution for several days to keep the structure of the polymer and the surrounding tissue in the harvested from .
all five polymer film samples were then embedded in paraffin wax , cut into 5 m thick sections , and stained with hematoxylin - eosin and mason 's trichrome . under the light microscope , in vivo behavior of each polymer was evaluated .
various histological sections from each harvested sample were observed by using an optical microscope with different magnifications . in each histological section
, there was a capsule formation in different thickness covering the implanted polymer film sample .
in vivo behavior of each polymer sample was discussed via intensity of the inflammatory reaction within this capsule .
the inflammatory reaction was categorized in four different groups : inflammatory cell population , collagen synthesis , thickness of the capsule , and new blood vessel formation named as neovascularization .
interpretation of inflammatory reaction for different polymer samples was performed by using a modified scale of marios et al . which was initially introduced to the literature via our previous study .
the thickness of the capsule surrounding the polymer sample was measured from four different standardized areas , one on each side of the implant .
the collagen proliferation , intensity of neovascularization , and inflammatory cell count were analyzed and scored in the same fashion .
scanning electron micrographs of the polymer samples were taken on a jeol jxa-6335 fs scanning electron microscope ( sem ) .
semiquantitative - inca - energy dispersive x - ray spectroscopy ( eds ) was also used for the assessment of metal nanoparticles . for the fracture surface assessment ,
the composite polymer samples were frozen under liquid nitrogen then fractured , mounted , and coated with palladium , gold , and carbon .
the sem was operated at 15 kv , and the electron images were recorded directly from the cathode ray tube on a polaroid film .
in this study , we have compared the in vivo properties and sem assessment of pp as control group and four different types of amphiphilic graft copolymers : pp - peg-2000 , pp - peg-4000 , au - pp - peg-2000 , and aupp - peg-4000 .
each polymer film was placed on the back of the rat in similar fashion with our previous studies [ 29 , 30 ] . throughout the implantation period ,
all the rats were healthy and there were no adverse reaction such as necrosis or abscess formation in the neighborhood of the implants .
neither of the films had abscess formation or adverse inflammatory reactions neighboring the polymer blocks since all sterilized polymer samples were implanted to rats in sterile condition .
pp polymer films were deeply embedded into the soft tissue and there was a thick , hard capsule formation around the sample which was hard to detach from the surrounding tissue ( figure 1 ) .
however , all other amphiphilic graft copolymers revealed thinner capsule formation than the pp polymer sample
. there was a moderate capsule formation around the pp - peg-2000 polymer film , and the physical appearance of pp - peg-4000 film was also similar with prominent vascular capsule .
on the other hand , au - pp - peg-2000 and au - pp - peg-4000 both had a very fine capsule which was hardly seen on the polymer .
capsule formation and blood supply of the surrounding tissue did not differ in between high- and low - molecular - weight side chains in both gold - nanoparticle - embedded and pure polypropylene polymer blocks .
we have analyzed the inflammation around the polymer film with a standard scoring described in our previous study .
soft tissue response of five different polymer blocks was analyzed according to the inflammatory reaction within the capsule ( table 1 ) . in every aspect of the inflammatory parameters , pp sample ( control group ) demonstrated the most prominent inflammatory reaction among all samples ( figures 2(a ) and 2(b ) ) .
collagen infiltration was intense in pp sample , and the least accumulation was seen in au - pp - peg-4000 .
neovascularization and inflammatory cell count were less in au - nanoparticle - containing polymer blocks compared to the au - free polymers .
however , gold - containing polymer blocks appeared to have more foreign - body giant cell count compared to pure pp and pp - peg polymer blocks . when pp - peg-2000 and au - pp - peg-2000 were compared , neovascularization and inflammatory cell count were lower in gold - nanoparticle - embedded block than the pure ones .
giant cells are lined on the polymer side of the capsule in front of the newly formed vessels ( figure 3(a ) ) . on the other hand
, there was a marked difference in the aspect of inflammation in between high- and low - molecular - weight polymer blocks independent of au nanoparticles .
inflammatory cell reaction in each of the 4000 weighted peg block copolymer was fairly mild compared to the 2000 weighted peg .
giant cell accumulation was also prominent in high - molecular - weight block copolymers . among all polymer blocks ,
gold - nanoparticle - embedded polymer film samples were presented with very fine inflammatory reaction .
there was a very few inflammatory cell migration with giant cells in majority around this polymer film sample compared to the au - pp - peg-2000 ( figures 3(a ) and 3(b ) ) .
new blood vessel formation in thin and loose capsule was seen in both histological sections , more prominent in high - molecular - weight polymer sample ( figure 3(b ) ) .
sem scans of pp polymer sample revealed no change after 30 days of implantation . in peg - attached polymer samples , whether they are au attached or not , there were some changes on the surface of the polymer . in all polymer samples
( except from pp sample ) , there were circular holes on the surface of the polymer with darkened spaces in the periphery .
the number of these holes was increased as the molecular weight of the polymer sample increase .
also au - attached polymer samples contained more holes on the surface than pure graft copolymers .
when the au - pp - peg-2000 and au - pp - peg-4000 were compared , there was a major difference in between ( figure 4(a ) ) .
there were multiple holes in various sizes on the surface of au - attached pp - peg-4000 ( figure 4(b ) ) .
since these holes are two dimensional , one can not decide whether these are embedded holes or crater - like elevated areas .
the same appearance was present in the light microscopic section of the au - attached polymer ( figures 5(a ) and 5(b ) ) . in both cases
, this appearance shows that there is major structural defect in implanted polymer block and this property might be the result of drying process of the swollen peg blocks of the graft copolymer .
since it is an unbreakable , elastic , and hydrophobic polymer and causes strong chronic inflammatory reaction , pp is a good substitute to reinforce weakened soft tissue , for example , inguinal or incisional hernias , abdominal wall or pelvic floor defects [ 34 , 35 ] .
however , its hydrophobicity and potent foreign - body reaction limit its other medical applications such as drug carriers or vascular grafts . in order to overcome these deficiencies and to broaden its medical applications ,
one approach is to prepare block copolymers containing hydrophilic blocks that can modify the hydrophilicity , crystallinity , mechanical properties , and biocompatibility of the original material . in this
regard , polyethylene glycol ( peg ) can be used as it is a popular hydrophilic and biocompatible polymer .
it has been shown that peg - grafted copolymers have the ability to reduce platelet adhesion and bacterial repulsion .
furthermore , nanoparticles especially gold nanoparticles embedded into the polymer structure were reported to enhance the biocompatibility and the antimicrobial effect of the polymer itself [ 28 , 30 ] .
therefore , pp can be modified to form a more biocompatible and antimicrobial polymer for in vivo applications via attaching gold nanoparticles and peg side chains . in our previous report
, we have already described the synthesis and characterization of nanoparticles embedded into amphiphilic comb - type graft copolymers .
a question may rise whether in vivo properties of the copolymer may be enhanced as the number of side chain attached to the original polymer increases .
therefore , in this present study , we have compared the soft tissue response of the pure pp polymer samples with gold - nanoparticle - embedded pp - peg copolymers and pure type pp - peg block copolymers in two different molecular weight forms following in vivo application via histochemical and sem assessment .
inflammatory cells such as polymorph nuclear cells and giant cells play an important role in the foreign - body reaction for any material implanted to living organism .
these cells are carried to the reaction site via newly formed vessels [ 39 , 40 ] .
pp had the most intense inflammatory reaction with highest inflammatory cell count and multiple blood vessels among all other polymer samples .
when the number of peg side chains is attached ( pp - peg-4000 ) , the inflammatory cells and collagen accumulation decrease and the sample becomes more biocompatible ( table 1 ) .
similar to our previous study , soft tissue response of the gold - nanoparticle - attached polymer blocks is found to be milder with lower cellular migration and less collagen formation .
au - pp - peg-4000 had the thinnest capsule formation with least cellular count ( figure 3(b ) ) .
these data indicate that both addition of gold nanoparticles and increasing the number of side chains in the block copolymer will facilitate the in vivo compatibility of the polymer itself .
pp - peg-2000 and au - pp - peg-2000 seemed to have similar sem scans , with minor superiority in number of holes in au - embedded copolymers .
however , gold - nanoparticles - embedded high - molecular - weight polymer block showed unexpected properties .
there were multiple craters like holes on the surface of the polymer , and this appearance was also present in the light microscopic sections ( figures 5(a ) and 5(b ) ) . in first glance these multiple punched holes
interestingly , similar appearance is seen on the light microscopic sections without passing through any drying process .
since these holes are present on the surface of the high - molecular - weight polymer blocks , they might be formed by the hydrophilic side chains .
these hydrophilic peg side chains attract the water in the microenvironment of the implantation area , and small blebs occur on the surface of the polymer .
as the number of hydrophilic and biodegradable peg side chains increases , the polymer absorbs more water and the number of crater - like holes on the surface of the polymer increases as well .
this property changes the soft tissue response of the pp polymer in favor of milder inflammatory reaction .
we have investigated in vivo behavior of pp , pp - g - peg2000 , pp - g - peg4000 , aupp - g - peg2000 , and aupp - g - peg4000 after 30 days of implantation and compared the inflammatory reaction and sem assessment of each of them .
overall , au - embedded polymer favors less inflammatory reaction when compared to pure pp - g - peg ones , and even more increased molecular weight of the polymer film with increased number of side chains of peg reveals milder inflammatory reaction compared to the low - molecular - weight ones . sem assessment also supports this data with a lot of holes on the surface of au - pp - g - peg 4000 .
however , featuring studies should be done to understand why these holes are present on the surface of the polymer after the in vivo implantation .
Output:
| the aim of this study is to evaluate the soft tissue response of the pure and au - embedded ppg - peg .
pp - g - peg2000 , pp - g - peg4000 , au - pp - g - peg2000 , and aupp - g - peg4000 were obtained via chlorination of polypropylene and polyethylene glycol in the presence of a base with a grafting onto technique .
solvent cast films of these four copolymers with pp as a control group were embedded into five different rats .
after 30 days of implantation , microscopic evaluation of inflammation and sem analysis were done .
pp had the most intense inflammatory reaction among the other polymers .
pp - peg block copolymers with high molecular weight and gold - nanoparticles - embedded ones revealed mild inflammatory reaction independently .
sem assessment revealed punched hole - like defects on the surface of all polymer samples except for pp .
graft copolymers with peg , especially au - attached ones , have favorable soft tissue response , and inflammatory reaction becomes milder as the number of peg side chains increases . |
PubmedSumm6570 | ***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 myeloid leukemia ( cml ) is a myeloproliferative disease that represents 15%25% of all leukemias .
the disease was the result of a reciprocal translocation between chromosome 22 and chromosome 9 , the so - called philadelphia translocation .
this rearrangement joins the c - abl gene on chromosome 9 and bcr on chromosome 22 creating a bcr - abl fusion gene , which codes for a 190230 kda , bcr - abl fusion protein with elevated tyrosine kinase activity .
the upregulated bcr - abl fusion protein includes the tyrosine kinase domain , which likely contributes to dysregulation of the mechanism of cellular signals transduction , normally involved in controlling apoptosis , proliferations , and cell - cell adhesions , and thus promoting leukemogenesis .
the abrogation of bcr - abl function has become a model for development of targeted therapies .
the enzymatic inhibition of bcr - abl using imatinib mesylate ( gleevectm , sti571 ; novartis pharmaceutical corp .
, east hanover , nj ) has been shown to possess potent in vitro and in vivo activities in preclinical studies [ 3 , 4 ] .
the activity of this inhibitor in patients with previously treated cml was further confirmed in early clinical trials [ 57 ] .
recently , the landmark international randomized study of interferon versus sti571 ( iris ) study has shown cytogenetic responses in 87% of their patients after 5 years of imatinib as a primary treatment . over the past few decades , allogeneic bone marrow transplantation ( allo - bmt ) has been used to treat cml and other malignant and nonmalignant diseases .
however , this success is frequently not maintained since leukemic relapse substantially occurs in 30% to 60% of patients who undergo transplantation during the advanced stages of disease ( accelerated phase and blast crisis ) and 5% to 20% of those who undergo transplantation during the chronic phase .
moreover , the impact of this potential treatment is limited because it depends considerably on the patient 's age and availability of a genetically cross matching donor with the same tissue type to prevent rejection .
the infusion of donor lymphocytes ( dli ) into cml patients who have relapsed following an allo - bmt has been frequently used and proved to effectively treat 70%80% of patients with relapsed chronic leukemia . however , this therapeutic option is less effective in patients with more advanced disease and may also be associated with severe marrow aplasia , high incidence of chronic graft - versus - host disease ( gvhd ) , and transplant - related mortality [ 1012 ] .
several studies have shown that the administration of imatinib is safe and highly effective in controlling leukemic relapses after allo - bmt [ 13 , 14 ] .
these compelling facts have made us adopt imatinib therapy as the preferred treatment at our institution . in this study
, we performed a retrospective analysis to determine the efficacy of imatinib administration in treating leukemic relapses after allo - bmt .
from january 2005 to january 2009 , a total of 7 cases with primary relapse of cml after allo - bmt undergoing treatment with imatinib were found after a retrospective search of the cml database at the department of cml ambulatory of the hospital das clinicas , so paulo university .
patients ' medical records were reviewed for the following : sex , age , date of cml diagnosis , time from diagnosis to transplant , time from transplant to relapse , disease stage at relapse , and other variables as shown in table 1 .
the extent of cml was staged ( chronic , accelerated or blast phase ) according to the 2008 revision of the world health organization staging system . in all patients ,
complete blood counts were performed weekly for the first month of follow - up and monthly thereafter .
quantification of bcr - abl transcript numbers was measured every 3 months by real - time pcr and conventional bone marrow cytogenetics were performed every 6 months and then every 12 months .
cytogenetic response was classified as complete ( no ph chromosome - positive cells in metaphase in the bone marrow ) , partial ( 1%34% ph chromosome - positive cells ) , or minor ( 35%90% ph chromosome - positive cells ) .
molecular response was considered major if the bcr - abl level was below 0.1% and complete when it was negative .
toxicities were assessed according to the national cancer institute common toxicity criteria version 3.0 ( national cancer institute , bethesda , md ) .
posttransplant allogeneic hematopoietic chimerism was evaluated by fluorescent - based pcr amplification and capillary gel electrophoresis of microsatellite dna str markers in sequential peripheral blood and bone marrow samples from the recipients using established techniques .
curves of overall survival and progression free survival were estimated using the kaplan and meier method .
all 7 patients received an allogeneic peripheral blood progenitor cell from hla - identical sibling .
the median time to diagnosis was 7.4 years after transplant . at the time of relapse
, four patients were classified as having a hematologic relapse , two as having a major molecular relapse , and one as having a cytogenetic relapse . the mean time from allobmt to detection of relapse was 4.02 years .
two patients received a dli as a salvage therapy after relapse to enhance donor engraftment without response .
of the seven patients , five had cml in a chronic phase at the time of imatinib initiation , while one patient was diagnosed as having accelerated phase and blast crisis .
imatinib was given at a dose of 400 mg / d ( five patients ) or 600 mg / d ( two patients ) .
this latter patient was in blastic crisis before imatinib administration and died of rapid disease progression 7 months after initiation of therapy , before hematologic recovery .
eventually , all patients could be evaluated for the therapeutic efficacy . at a mean of follow - up of 1.8 years of imatinib therapy ,
all but one patient had achieved complete hematologic , cytogenetic , and major molecular response .
response to imatinib was then evaluated based on relapse classification and found that all but one patient with hematologic relapse achieved major molecular response .
analyses of the safety data in patients who remained alive indicate that the treatment was generally well tolerated and that most of toxicities were mild and transient .
four patients experienced grade 2 hematological toxicities , while one patient developed grade 2 alterations in hepatic enzymes .
the estimated overall and progression - free survivals were 7.1 and 2.1 years , respectively .
a number of therapeutic interventions have met with varying degrees of success in the treatment of cml patients with relapse after allo - bmt .
these options include a second transplant [ 19 , 20 ] , conventional cytotoxic chemotherapy , and interferon - alpha . each treatment , however , has limitations .
for example , although the option of second allo - bmt offers a prospect of cure , it is limited to young patients with good performance status and is associated with a very poor outcome [ 10 , 21 , 22 ] .
evidence from several reports indicated a high remission rate ( 70%80% ) after dli in chronic phase cml .
however , the success of this option has been limited by short duration of response , myelosuppression , significant gvhd , and rare long - term survival [ 1 , 5 , 19 ] .
it is therefore important to consider the effects of the alternative therapies listed above on outcomes .
the recent use of imatinib mesylate as new therapeutic approach is eventually become accepted as the preferred treatment of posttransplant relapse setting and offers a number of potential advantages over dli including fewer adverse effects and relatively rapid and durable response . apart from our study ,
several anecdotal and clinical trials have examined the use of imatinib in patients with relapse after bmt .
the largest of these was a prospective phase ii open label multicenter study by hess et al . who examined the use of imatinib therapy in 44 relapsed patients .
in this 494-day median follow - up study , patients were treated with imatinib at starting dose of 400 mg / d and escalated to 600 mg / d to 800 mg / d if patients did not achieve mmr . of the 37 patients assessable for efficacy analysis , a total of 23 patients ( 62% ) had a cmr during the initial 9 months , which improved to 70% during follow - up .
therapy was generally well tolerated , with a main adverse event of neutropenia / leucopenia .
the review by palandri and coworkers of the outcomes of 16 patients who received imatinib as first or second line therapy showed that 93% of this group achieved a molecular negativity after 327 months and 75% had negative reverse transcriptase - polymerase chain reaction after 1245 months . similarly , hayat et al
. found , in a group of 14 patients who relapsed postallo - bmt from the preimatinib era , that 93% had achieved excellent response to imatinib with a median time of 4 months . in this study , although the sample size is small , imatinib maintained mmr in all 6 evaluable patients for an average time of 21 months of follow - up .
all patients are still on treatment with imatinib and have full - donor chimerism according to the last analysis .
generally , the results presented here compare favorably with the outcomes from previous studies [ 13 , 19 , 25 ] and lend support to the conclusion that the imatinib therapy is efficiently improving outcome even further in patients with relapse after bmt particularly for chronic phase cml without compromising safety .
although the introduction of imatinib has obviously been a major step forward a high objective response and disease stabilization rate in patients with relapse after bmt , several questions still remain open . among them , how well does imatinib perform over the long - term of therapy ?
is there a tendency for some patients to gradually relapse overtime passage ? can patients eventually stop their therapy without relapsing ? to provide answers to these questions , additional double - blind imatinib - placebo controlled research of long - term follow - up is needed to further evaluate the safety of a long - term , continuous therapy with the imatinib in a large number of patients with relapse after bmt .
Output:
| we describe the
response of imatinib as lifesaving treatment of
chronic myeloid leukemia ( cml ) relapse in seven
patients who underwent allogeneic bone marrow
transplantation ( allobmt ) at our institution
over a period of 4 years .
retrospective analysis
of their medical records revealed that a mean age at
transplant was 45.2 years .
the median time to
diagnosis was 7.4 years after transplant . at
relapse ,
four , two , and one patients were
classified as having hematologic , major
molecular , and cytogenetic relapse , respectively .
at imatinib initiation ,
five had cml in a
chronic phase , while one patient was
diagnosed as having accelerated phase and blast
crisis .
all these patients could be evaluated
for the therapeutic efficacy . at a mean of
follow - up of 1.9 years of therapy , all
evaluable
patients achieved major molecular response
without compromising safety .
consistent with
available data , our results indicate that
imatinib is safe and effective treatment option
for patients with relapse after
bmt . |
PubmedSumm6571 | ***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: participants included 613 youth ( 52% female ) enrolled in grades 6 ( 35% ) , 7 ( 29% ) and 8 ( 36% ) at study outset .
the ethnic composition of the sample included 86% white / caucasian , 4% asian - american , 2% latino / a - american , 1% african - american , and 6% mixed ethnicity students .
participants were enrolled in a single public middle school within a city of fairly homogeneous middle - class socioeconomic status . according to school records ,
11% of children were eligible for free / reduced - price lunch . at time 1 , all sixth through eighth grade students and their families received mailed and hand - distributed consent forms for study recruitment with strong encouragement and incentives ( e.g. , raffles ) for consent form return .
consent forms were returned by 92% of families ( n = 784 ) ; of these , 80% of parents gave consent for their child s participation ( n = 627 ; 74% of the total population ) .
students who were absent on one of the days of testing ( n = 10 ) or refused to participate ( n = 4 ) , were excluded from analyses , yielding a final sample of 613 participants at time 1 . a total of 567 ( 92% ) of these participants were available for testing eleven months later ( i.e. , time 2 ) , when students were in grades seven through nine .
attrition was due to participants moving away from the area ( n = 36 ) , absenteeism ( n = 7 ) , and three participants who refused to continue participation . no significant differences were revealed for any of the constructs measured in this study between adolescents who participated at both time points and those who only participated at one time point . because listwise deletion would unnecessarily omit valuable data , all analyses were conducted with all available data ( see data analyses below ) .
analyses using only available data revealed an identical pattern of results . at time 1 , measures of pubertal timing , depressive symptoms , and reputation - based peer status ( i.e. , popularity ) were administered .
( i.e. , time 2 ) , participants completed a second measure of depressive symptoms .
1988 ) includes five items for boys ( e.g. , growth spurt , body hair , skin change , voice change , facial hair ) and girls ( e.g. , growth spurt , body hair , skin change , breast growth , menarche ) measuring gender - specific physical changes associated with maturation .
adolescents respond to each item using a four point likert scale ( 1 = not started ; 4 = seems completed ) .
as in past research ( mcbride et al . 2003 ) , responses for girls menarche were coded ( 1 = no ; 4 = yes ) to create a scale comparable to other items and a mean score across all five items was computed for both girls , = 0.75 , and boys , = 0.79 , with higher scores indicating more advanced pubertal development .
pubertal development scores were standardized within grade , within gender to obtain a measure of pubertal timing .
popularity a sociometric peer nomination questionnaire was used to measure the peer status of participants .
each team was about twice the size of a traditional academic classroom ( ns = 3075 ) . an alphabetized list of all teammates was presented to each participant and they were asked to select an unlimited number of peers that were most popular and peers that were least popular .
the order of the names on this list was counterbalanced ( a through z or z through a ) to control for possible effects of order on the selection of peers . for each participant
scores then was computed and re - standardized as a measure of social reputation , with higher scores indicating higher levels of popularity .
peer nominations are considered the most reliable and valid method to measure various dimensions of peer status and reputations in adolescence ( jiang and cillessen 2005 ) .
depressive symptoms the children s depression inventory ( cdi ; kovacs 1981 , 1985 ) is a 27-item measure designed to assess depressive affect and symptoms . for each item ,
the participant is provided with three alternative statements and instructed to select the one that best describes their symptoms over the past 2 weeks ( e.g. ,
i am sad many times , and i am sad all the time ) .
responses are coded on a scale of 02 , with higher scores indicating heightened depressive symptoms .
the cdi is well - established as a reliable and valid assessment of depressive symptoms in children between the ages of 7 and 18 years ( smucker et al .
descriptive statistics first were conducted to examine the gender differences in the primary study variables , as well as intercorrelations .
hypotheses were examined with a multiple group ( by gender ) structural equation model using full information maximum likelihood as implemented in amos version 16.0 .
means and intercepts were estimated using full information direct maximum likelihood when data were missing .
depressive symptoms at time 1 and time 2 were estimated as latent variables by creating three item parcels of the cdi .
each parcel is the summed score on a subset of 9 items . to create parcels
we examined the unidimensionality of the cdi using confirmatory factor analysis ( cfa).2 from these results we may infer that the latent variable
for the construction of the three parcels we used the item - to - construct balance method as described in little et al .
( 2002 ) . a 1-factor solution at time 1 was used to allocate items to one of the three parcels according to the magnitude of the factor loadings . in this way each parcel reflected the original factor structure with higher and lower factor loadings .
the alpha s of the parcels at t1 were 0.75 , 0.76 and 0.75 , and at t2 0.77 , 0.75 , 0.68 . in the model error terms of identical parcels over time
were correlated ( finkel 1995).3 a multiple group ( by gender ) structural equation model was estimated to examine the primary hypotheses regarding a three - way interaction between pubertal timing , popularity , and gender .
the model included an estimated autocorrelation between latent variables for depressive symptoms at time 1 to time 2 .
paths were estimated between both exogenous predictors ( i.e. , pubertal timing , popularity ) and time 2 depressive symptoms , as well as between a product term between these two variables ( pubertal timing x popularity ) predicting time 2 depressive symptoms . to examine hypotheses in a stringent manner ,
two additional variables were entered as predictors : age , and a product term between age and popularity .
the error terms for the depressive symptoms parcels at time 1 were allowed to correlate with the error terms for the corresponding depressive symptoms parcels at time 2 .
gender interactions were examined by comparing models with paths either fixed or free to vary between groups , and the significance of chi - squared difference tests between nested models was used to examine statistically significant gender differences in the magnitude of estimated paths . unless otherwise noted , all parameter estimates were allowed to vary freely by gender ( see fig . 1 ) .
1structural equation model examining popularity as a moderator of the longitudinal association between pubertal timing and depressive symptoms , while controlling for age effects structural equation model examining popularity as a moderator of the longitudinal association between pubertal timing and depressive symptoms , while controlling for age effects
1988 ) includes five items for boys ( e.g. , growth spurt , body hair , skin change , voice change , facial hair ) and girls ( e.g. , growth spurt , body hair , skin change , breast growth , menarche ) measuring gender - specific physical changes associated with maturation .
adolescents respond to each item using a four point likert scale ( 1 = not started ; 4 = seems completed ) . as in past research ( mcbride et al .
2003 ) , responses for girls menarche were coded ( 1 = no ; 4 = yes ) to create a scale comparable to other items and a mean score across all five items was computed for both girls , = 0.75 , and boys , = 0.79 , with higher scores indicating more advanced pubertal development .
pubertal development scores were standardized within grade , within gender to obtain a measure of pubertal timing .
popularity a sociometric peer nomination questionnaire was used to measure the peer status of participants .
each team was about twice the size of a traditional academic classroom ( ns = 3075 ) .
an alphabetized list of all teammates was presented to each participant and they were asked to select an unlimited number of peers that were most popular and peers that were least popular .
the order of the names on this list was counterbalanced ( a through z or z through a ) to control for possible effects of order on the selection of peers . for each participant
scores then was computed and re - standardized as a measure of social reputation , with higher scores indicating higher levels of popularity .
peer nominations are considered the most reliable and valid method to measure various dimensions of peer status and reputations in adolescence ( jiang and cillessen 2005 ) .
depressive symptoms the children s depression inventory ( cdi ; kovacs 1981 , 1985 ) is a 27-item measure designed to assess depressive affect and symptoms . for each item ,
the participant is provided with three alternative statements and instructed to select the one that best describes their symptoms over the past 2 weeks ( e.g. ,
i am sad many times , and i am sad all the time ) .
responses are coded on a scale of 02 , with higher scores indicating heightened depressive symptoms .
the cdi is well - established as a reliable and valid assessment of depressive symptoms in children between the ages of 7 and 18 years ( smucker et al .
descriptive statistics first were conducted to examine the gender differences in the primary study variables , as well as intercorrelations .
hypotheses were examined with a multiple group ( by gender ) structural equation model using full information maximum likelihood as implemented in amos version 16.0 .
means and intercepts were estimated using full information direct maximum likelihood when data were missing .
depressive symptoms at time 1 and time 2 were estimated as latent variables by creating three item parcels of the cdi .
each parcel is the summed score on a subset of 9 items . to create parcels
we examined the unidimensionality of the cdi using confirmatory factor analysis ( cfa).2 from these results we may infer that the latent variable
for the construction of the three parcels we used the item - to - construct balance method as described in little et al .
a 1-factor solution at time 1 was used to allocate items to one of the three parcels according to the magnitude of the factor loadings . in this way each parcel reflected the original factor structure with higher and lower factor loadings .
the alpha s of the parcels at t1 were 0.75 , 0.76 and 0.75 , and at t2 0.77 , 0.75 , 0.68 . in the model error terms of identical parcels over time
were correlated ( finkel 1995).3 a multiple group ( by gender ) structural equation model was estimated to examine the primary hypotheses regarding a three - way interaction between pubertal timing , popularity , and gender .
the model included an estimated autocorrelation between latent variables for depressive symptoms at time 1 to time 2 .
paths were estimated between both exogenous predictors ( i.e. , pubertal timing , popularity ) and time 2 depressive symptoms , as well as between a product term between these two variables ( pubertal timing x popularity ) predicting time 2 depressive symptoms . to examine hypotheses in a stringent manner ,
two additional variables were entered as predictors : age , and a product term between age and popularity .
the error terms for the depressive symptoms parcels at time 1 were allowed to correlate with the error terms for the corresponding depressive symptoms parcels at time 2 .
gender interactions were examined by comparing models with paths either fixed or free to vary between groups , and the significance of chi - squared difference tests between nested models was used to examine statistically significant gender differences in the magnitude of estimated paths . unless otherwise noted , all parameter estimates were allowed to vary freely by gender ( see fig . 1 ) .
1structural equation model examining popularity as a moderator of the longitudinal association between pubertal timing and depressive symptoms , while controlling for age effects structural equation model examining popularity as a moderator of the longitudinal association between pubertal timing and depressive symptoms , while controlling for age effects
means and standard deviations for all variables included in this study are presented in table 1 . as would be anticipated , t - tests indicated that girls reported higher levels of depression at time 2 than boys .
pubertal timing was positively related to depressive symptoms at time 1 and time 2 ( for girls only ) .
low levels of popularity were associated with high levels of depressive symptoms at time 1 ( for boys and girls ) and time 2 ( for girls only ) .
table 1means ( and standard deviations ) for primary variables at time 1 and time 2boysgirlst ( 613)time 1 depressive symptoms0.27 ( 0.24)0.30 ( 0.27)1.13 pubertal development ( unstandardized)2.30 ( 0.63)2.77 ( 0.73)8.91 * * popularity0.03 ( 1.03)0.09 ( 0.93)1.46 age ( in months)151.57 ( 11.64)150.78 ( 10.84)0.88time 2 depressive symptoms0.21 ( 0.20)0.25 ( 0.25)2.02**p < 0.05 ; * * p < 0.0001table 2bivariate associations among primary variablestime 1time 2depressive symptomspubertal timingpopularityagedepressive symptomstime 1 depressive symptoms0.020.19**0.070.60 * * * pubertal timing0.12 * 0.090.13 * 0.02 popularity0.20**0.030.080.10 age0.000.100.040.14*time 2 depressive symptoms0.75***0.16**0.19**0.05*correlations for males appear above the diagonal ; correlations for females appear below the diagonal.*p < 0.05 ; * * p < 0.01 ; * * * p < 0.001 means ( and standard deviations ) for primary variables at time 1 and time 2 * p < 0.05 ; * * p < 0.0001 bivariate associations among primary variables correlations for males appear above the diagonal ; correlations for females appear below the diagonal . *
p < 0.05 ; * * p < 0.01 ; * * * p < 0.001 results suggested that an initial model with all paths , factor weights , covariances , and error terms freely varying across gender was a satisfactory fit to the data , ( 104 ) = 85.99 , p < 0.001 ; /df
= 1.72 ; cfi = 0.99 ; rmsea = 0.03 .
paths , covariances , and error terms systematically were constrained across gender to examine improvement in model fit . for all but five estimated parameters
two of these parameters represented gender differences in covariances : ( 1 ) covariance between the two product terms in model : 0.61 for girls , ns ; 3.64 for boys , p < 0.001 ; = 13.82 , p < 0.001 ; ( 2 ) covariance between pubertal timing and depressive symptoms : 0.35 for girls , p < 0.01 ; 0.10 for boys , ns ; = 7.46 , p < .01 ) .
two parameters represented differences in factor weights ( 1 ) parcel 2 at time 2 : 1.03 for girls , p < 0.001 ; 1.27 for boys , p < 0.001 ; = 5.23 , p < 0.05 ; ( 2 ) parcel 3 at time 2 : 0.95 for girls , p < 0.001 ; 1.36 for boys , p < 0.001 ; = 14.04 , p < 0.001 .
last , the autocorrelation of depressive symptoms over time was moderated by gender : 0.82 for girls , p <
0.001 ; 0.51 for boys , p < 0.001 ; = 15.11 , p < 0.001 .
the autocorrelation path between depressive symptoms at both time points was statistically significant for boys and girls .
after accounting for this association , no significant interaction between age and popularity was revealed in the prediction of depressive symptoms either for boys or girls .
the results suggested that the interaction term ( pubertal timing x popularity ) was associated significantly with time 2 depressive symptoms ( see table 3 ) .
however , contrary to hypotheses , a chi - square difference test suggested no significant detriment to model fit when constraining this path across gender as compared to when allowing this path to vary freely , ( 1 ) = 2.44 , p = 0.12 , suggesting that gender did not further moderate the pubertal timing x popularity interaction .
the final model was a good fit to the data , ( 72 ) = 104.79 , p < 0.01 ; /df
= 1.46 ; cfi = 0.99 ; rmsea = 0.03 ( 90% ci 0.01 to 0.04 )
table 3unstandardized path coefficients , standard errors , and standardized path coefficients for structural equation model examining longitudinal associations between pubertal timing , popularity , age , and depressive symptoms at time 1 with depressive symptoms at time 2 , for boys and girlsunstandardized(se)standardizedtime 1depressive symptomspubertal timing0.03(0.06)0.01popularity0.01(0.06)0.00age0.01(0.01)0.07*age popularity0.01(0.01)0.03pubertal timing popularity0.29(0.11)0.11*this path weight was moderated by gender , girls : unstandardized = 0.82 ( 0.05 ) , standardized = 0.81 * * ; boys : unstandardized = 0.51 ( 0.05 ) , standardized = 0.67***p < 0.01 ; * * p < 0.001 unstandardized path coefficients , standard errors , and standardized path coefficients for structural equation model examining longitudinal associations between pubertal timing , popularity , age , and depressive symptoms at time 1 with depressive symptoms at time 2 , for boys and girls this path weight was moderated by gender , girls : unstandardized = 0.82 ( 0.05 ) , standardized = 0.81 * * ; boys : unstandardized = 0.51 ( 0.05 ) , standardized = 0.67 * * * p < 0.01 ; * * p < 0.001 to examine the interaction between pubertal timing and popularity , a reduced model next was estimated including only prior levels of depressive symptoms , the main effects of hypothesized predictors , and interaction term ( i.e. , removing age and the interaction between age and popularity as predictors to ensure that findings were not due to suppression effects ; holmbeck 2002 ) .
this reduced model was a good fit to the data , ( 46 ) = 81.72 , p < 0.01 ; /df = 1.78 ; cfi = 0.98 ; rmsea = 0.03 .
the interaction between pubertal timing and popularity as a longitudinal predictor of depressive symptoms remained significant , b = 0.14 , p < 0.05 .
results of simple slope analyses were conducted for adolescents scoring low ( 1 sd ) , average , or high ( + 1 sd ) in popularity . for adolescents with low levels of popularity , advanced pubertal timing compared to peers ( i.e. , early pubertal timing )
was associated with high levels of depressive symptoms at time 2 , slope = 0.18 , t = 2.11 , p < 0.05 . for adolescents average or high in popularity ,
the association between pubertal timing was not associated significantly with time 2 depressive symptoms , slopes = 0.04 and 0.09 , ts = 0.81 and 1.14 , ns , respectively .
this study examined popularity as a potential moderator of the relationship between early pubertal timing and the development of depressive symptoms over a one year interval . it was expected that this effect would be revealed only for girls .
results revealed a significant moderating effect of popularity , however , surprisingly , significant effects were revealed both for boys and girls .
specifically , the positive relationship between early pubertal timing and increases in depressive symptoms was revealed for adolescents with a low social reputation , but not among adolescents with a high social reputation .
these results suggest that a high social reputation may protect early maturing adolescents from the development of depressive symptoms over time , while a low social reputation may be a risk factor for the development of depressive symptoms .
the findings supported an integrated biological - interpersonal model in examining the development of depressive symptoms during adolescence .
the interaction between pubertal timing and social reputation in predicting the change in depressive symptoms may explain why studies that have focused solely on the association between early pubertal timing and depressive symptoms , or on the relationship between social reputation and depressive symptoms , have yielded mixed results ( e.g. canals et al .
2003 ; la greca and harrison 2005 ; prinstein and la greca 2002 ; stroud and davila 2008 ) .
the additional consideration of peer status as a moderator is consistent with biopsychosocial models , which remind us to consider transactions that occur between social , biological and psychological systems in understanding the development of psychopathology .
it appears that the inclusion of peer status as a moderator provides a more complete picture of the relationship between early pubertal development and the development of depressive symptoms over time .
the finding that interpersonal factors interact with pubertal timing in predicting depressive symptoms is consistent with a study by conley and rudolph ( 2009 ) , which revealed that early pubertal timing was related to depressive symptoms in adolescents who experienced high levels of peer stress , but not in adolescents who experienced low levels of peer stress .
examples of peer stress included fights with peers or being teased by peers , social exclusion , and low support or poor quality of friendships .
the authors suggested that early pubertal timing is a diathesis for depressive symptoms that is activated when it occurs in a stressful peer context .
this model offers one possible interpretation of the current study s findings : popularity may reduce the incidence of certain interpersonal stressors associated with early maturation ( i.e. , reduce the likelihood of peer victimization ) , and thus may serve as a protective factor against the development of depressive symptoms .
further studies assessing the incidence of peer victimization and other social stressors among popular versus unpopular early developing adolescents could determine whether popularity does , in fact , buffer against depression by decreasing the incidence of social stressors .
such a finding would provide evidence that the moderational effect of peer status may be a proxy for increased exposure to social stressors , which interact with the biological ( i.e. , hormonal ) and social - cognitive ( i.e. , self - appraisal ) vulnerabilities posed by early development to predict the onset of depressive symptoms .
notably , however , conley and rudolph s ( 2009 ) results were significant for girls , and not for boys .
although the data in this study trended in a similar direction , the role of gender in further moderating hypothesized effects did not reach significance .
in addition , absent substantial data confirming the measurement and scalar invariance of the cdi across gender , it is difficult to make strong interpretations regarding gender effects conclusively ( see carle et al .
. it may be that among males , early pubertal timing combined with low peer popularity also presents risks for depressive symptoms over time .
it is likely that early pubertal timing may become a source of ridicule or ostracism among boys who already are unpopular , but perhaps a source of status and esteem among boys who enjoy high levels of popularity .
the finding that the relationship between early pubertal timing and depressive symptoms is moderated by popularity is a step forward in understanding both the inconsistent findings of past research in this domain , and the uniqueness of the adolescent period in the development of depression .
furthermore , the use of a longitudinal , prospective design allowed for examination of the temporal relationship between these variables . despite these strengths , several limitations of the current study highlight the somewhat tentative nature of these results .
first , results of conley and rudolph s ( 2009 ) study discussed above serve as a reminder that the construct of peer status may serve as a proxy for level of social stress or other related variables .
indeed , several interpersonal variables ( e.g. , social stress , peer - perceived attractiveness , friendship quality , etc . ) correlate highly with popularity , and can not be meaningfully examined as orthogonal moderators of the relationship between early pubertal development and depression .
other variables that correlate with popularity could explain the difference in depressive symptoms between popular and unpopular early maturing youth .
socioeconomic status , for example , is positively correlated with membership in the popular group ( brown et al .
all participants had similar ses , so in our sample this factor could not explain the relationship between popularity and the change in depressive symptoms in early maturing adolescents .
another important factor that might explain the difference in depressive symptoms among popular and unpopular early maturing adolescents is social connectedness .
adolescents with high social connectedness feel close with peers , easily identify with others and participate in social activities ( lee et al .
popularity is associated with social connectedness , while unpopularity is related to social withdrawal and a lack of skills to fit in with peers ( lafontana and cillessen 2002 ) .
other findings indicate a negative relationship between social connectedness and depressive symptoms , suggesting that adolescents who are socially less well connected are more likely to experience depressive symptoms ( lee et al .
this could suggest that low levels of social connectedness in unpopular adolescents are related to high levels of depressive symptoms .
social connectedness could then be the underlying factor that accounts for the difference in depressive symptom scores between popular and unpopular early maturing adolescents .
further research is needed to determine mechanisms by which early puberty confers risk for the development of depressive symptoms among adolescents .
while the current study provides valuable information about one potential moderator of this relationship , interpretations regarding the process ( i.e. , how popularity may buffer against the development of depressive symptoms for early developing adolescents ) remain theoretical .
some research suggests that european american adolescents , but not african american adolescents , experience more depressive symptoms following early maturation ( michael and eccles 2003 ) . this difference might be explained by the finding that african and african - american women , in particular , report a preference for a body type and size that is more consistent with a post - pubescent body ( i.e. , larger and curvier ) , whereas caucasian women report a preference for a thinner body type ( cogan et al .
consistent with this idea , siegel and colleagues ( 1999 ) found that african american girls , compared to caucasian and latino girls , are unique in their level of body satisfaction during adolescence .
however , more recent research has found a positive relationship between early pubertal timing and depressive symptoms in african american girls ( ge et al .
studies further examining the role of ethnicity in the association between pubertal timing and depressive symptoms should note that ethnicity should be considered in the context of the overall community in which adolescents live . note that african - american adolescents develop earlier than caucasian adolescents ( herman - giddens et al .
are more likely to be characterized as early maturers , while they might be on - time compared to their african - american agemates
. it may be important for research to consider pubertal timing with respect to same - ethnicity peers ( ge et al .
an additional limitation in this study pertains to the use of self - report measures to assess pubertal timing . although the pds is a widely used scale to measure pubertal development , it assesses perceived pubertal maturation instead of objective pubertal maturation . adding
more objective measures of pubertal maturation ( e.g. , physician ratings ) would strengthen the reliability of our findings ( dorn et al . 2003 ) .
conversely , the use of peer - reported measures to assess popularity offers the possibility that different peers ( e.g. , males vs. females ) use different standards to determine who is popular .
this issue also leads to invariance within the measurement of key constructs . despite these limitations ,
the present study provides insight into the relationship between early pubertal timing and the development of depressive symptoms .
the results indicate that early pubertal timing does not directly predict depressive symptoms among adolescents . instead , individual differences in popularity appear to affect the nature of this relationship .
these findings indicate that the interaction between individual development and the peer context may be important for understanding the relationship between pubertal timing and depressive symptoms .
future studies are likely to benefit from a similar biopsychosocial perspective in understanding the complex interactions between various systems in determining typical versus atypical development
. the findings of the current study may have important implications for prevention of depressive symptoms .
our results provide a more complete profile of adolescents who may be at risk for the development of depressive symptoms .
interventions that target early maturing , unpopular adolescents therefore may serve to reduce the prevalence of depressive symptoms among youth .
evidence that social skills and social connectedness are related to both social status and depression ( lafontana and cillessen 2002 ; lee et al .
2001 ) suggests that interventions that focus on these constructs might help to reduce risk for depression among adolescents . along these same lines ,
focusing on resiliency factors and resources for adolescents who are at risk may be beneficial .
the introduction of these and other resiliency factors through targeted interventions might aid in disconnecting the trajectory from risk factors to the development of depressive symptoms ( fergus and zimmerman 2005 ) .
furthermore , psychoeducation also could be a crucial element in the prevention of depressive symptoms .
early maturing adolescents may perceive themselves as deviant from their peers , and this perception of abnormality may negatively affect well - being .
psychoeducation aimed at informing adolescents about pubertal maturation , and the individual differences in its timing , might result in more personal and social acceptance of variations in puberty ( conley and rudolph 2009 ) .
psychoeducation also could help to prepare adolescents for the transition to puberty , and might even serve to reduce the accompanying psychosocial difficulties by normalizing the physical and social changes associated with pubertal development .
the current study has provided a clearer picture of the relationship between pubertal development , peer status , and the development of depressive symptoms over time .
it appears that early pubertal timing and low social status converge to create a high - risk context for the development of depressive symptoms among adolescents .
treatment strategies that seek to alter this trajectory may benefit from strategies that both increase peer status , and decrease the psychosocial impact of early maturation
. several such strategies , suggested above , may represent complementary approaches in the reduction of depressive symptoms .
Output:
| the transition to adolescence marks a time of sharply increased vulnerability to the development of depression , particularly among girls .
past research has examined isolated risk factors from individual theoretical models ( e.g. , biological , interpersonal , and cognitive ) of depression , but few have examined integrative models .
this study investigated the conjoint effects of early pubertal timing and popularity in the longitudinal prediction of depressive symptoms .
a total of 319 girls and 294 boys ( ages 1114 ) provided information on their pubertal status , depressive symptoms , and the social status ( i.e. , popularity ) of their peers .
adolescents completed a second measure of depressive symptoms 11 months after the initial time point .
findings supported an integrated biological - interpersonal model in explaining the development of depressive symptoms during adolescence .
early pubertal development was associated with increase in depressive symptoms only when accompanied by low levels of popularity .
high levels of popularity buffered the association between early pubertal development and later depressive symptoms .
unexpectedly , these results were significant both for girls and boys .
results are discussed in terms of dynamic systems theories . |
PubmedSumm6572 | ***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: atypical fibroxanthoma ( afx ) is a malignancy developed typically in the dermis of the head and neck of senior caucasians , however it is a very rare tumor in asians [ 1 - 5 ] .
in addition , the incidence of afx in koreans is very low and only 6 cases developed in the sun - exposed face and hand area have been reported in dermatology [ 6 - 10 ] . although the metastatic potential is known to be low , it grows rapidly and has a highly local recurrent ability . it must be differentiated from many diseases since it shows the sarcoma pattern consisting of atypical spindle cells within the dermis histology .
it can also be considered a benign lesion because there is no pain or local invasion clinically . although rare , metastases have been reported , and they could not be differentiated from malignant fibrous histiocytoma ( mfh ) histopathologically . as a treatment ,
however , local recurrence can occur frequently because the margin is not distinct when performing an excision .
therefore , a wide excision has been known to be the most effective . in this study , we examine a case diagnosed as atypical fibroxanthoma in the head and neck area , and report this case with a review of the literature .
our patient was a 70-year - old male who 3 months ago underwent an incision biopsy at another hospital for a 1.01.0 cm sized palpable and protruding reddish nodule in the left infra - auricular area . by result of a histological test ,
a malignant tumor was suspected and he was transferred to our hospital . in the physical examination , there was a round scar remaining from the previously performed biopsy and the size of the resected tissue was approximately 0.70.7 cm .
the specimen acquired at the other hospital was examined again at our hospital . in our histopathologic
finding , we detected a numerously mitotic figure with atypical , bizarre , large and hyperchromatic nuclei ( fig .
, we had cd34 , cd45 , cytokeratin and desmin showing negative reaction with a positive reaction for vimentin as well as cd68 .
in addition , the malignancy was confirmed in the previous incision margin , and there was no special findings in a metastatic work - up .
therefore , a wide excision was performed with 2 cm safety resection margin around the lesion which underwent the initial incision biopsy , and there was no malignancy detected by frozen biopsy ( fig .
twelve months have passed after surgery and the patient is under the follow - up observation at our outpatient clinic without any local recurrence .
an afx is a rapid growing neoplasm with low metastatic potential , but local recurrence is estimated at between 2%-20% and metastasis has been reported .
it is a solitary nodule smaller than 2 cm in diameter in most cases and it occurs on the face as well as the back of the hand in caucasians older than 50 years ( average , 70-year - old ) in the sun - exposed area [ 1 - 5 ] .
it is thought that the length of sun exposure , trauma and previous cutaneous neoplasm history as well as previous radiation history are all involved in the risk factors in the development of afx .
histopathologically , it commonly accompanies ulceration in the epidermis covering the lesion and there is a partial protrusion shape compared with adjacent tissue .
pleomorphic tumors with an indistinct border adjacent to the dermis - epidermis junction are shown .
tumor cells are primarily atypical spindle cells , multinucleated giant cells with a strange shape that can not be characterized and are also mixed with pleomorphic cells .
many mitosis are observed and cells similar to fibroxanthoma are densely distributed and surround the skin adnexa . with immunohistochemical staining , it is positive for vimentin .
however , it shows negative for cd34 , cytokeratin , desmin , and s-100 protein [ 1 - 5 ] .
diseases to be differentiated are dermatofibrosarcoma protuberance ( dfsp ) , mfh , leiomyosarcoma , spindle cell cancer , squamous cell carcinoma , etc . from the aspect of clinical findings ,
, mfh is similar to afx , however mfh occurs preferentially in the limbs and deep invasion is frequent which is different from afx .
there is also a positive result for vimentin , and a negative result for cd34 and s-100 protein .
leimyosarcoma or squamous cell tumors could be differentiated by histologic findings as well as immunohistochemistry test .
recently , the expression of cd99 and s-100a6 has been reported to be a useful immunohistochemical test indicator for the diagnosis of afx .
regarding afx treatments , although the tumor shows histological malignancy findings , the site of the lesion is the superficial layer in most cases , and the tumor shows a benign course since its metastatic potential is low . it could be treated by complete resection with 2 cm safety resection margin creating a good prognosis .
however , in the case of a large tumor or a tumor lacking a distinctive border , the recurrence and metastasis are more frequent .
our patient had a mass developed in the infra - auricular area which looked like a benign nodule and underwent an incision biopsy .
since it was diagnosed as an atypical fibroxanthoma in the histopathologic test , a complete resection was done with 2 cm safe margin around the initial lesion .
the postsurgical follow - up observation period was just 1 year , which may be short for malignant tumor case .
therefore we think we can check the recurrence status every three months for a 2 year period . in my opinion ,
typically , in this case , a simple incision biopsy is preferred because of the simplicity of surgery and less discomfort to the patients . however , we believe it needs to be an excisional biopsy even if it is a simple nodule , because it may give rise to more serious problem and we can not completely exclude the possibility of malignant tumor .
we think this case is very important because , it is not only a rare case in a korean , but also consider the question of the diagnosis of a neck mass once more . as a result , we report this case together with a review of the literature .
Output:
| atypical fibroxanthoma is a pleomorphic spindle cell tumor of the dermis and it 's been known to be a benign lesion clinically in spite of malignant histologic features .
but recurrence is estimated at between 2%-20% and metastasis has been reported .
we are about to describe a 70-year - old man with the lesion developed on the left infra - auricular area .
the lesion was located superficially and is composed of compact pleomorphic spindle cells and several bizarre multinucleated giant cells .
the patient was treated with wide excision .
we would like to discuss about this case with a review of literatures . |
PubmedSumm6573 | ***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 investigate the prevalence of different plasmodium spp . in wild great apes living in their natural habitat ( tropical rainforests ) , we analyzed tissue samples from 16 wild west african chimpanzees that died primarily of anthrax or respiratory disease in ta national park , cte divoire .
a generic real - time pcr that detects all known plasmodium spp . was used to test all samples for the parasite .
sequence analysis of the cytb gene and small subunit rrna genes was conducted for real - time pcr positive samples to determine the strain present ; 1,140 bp of the cytb gene and 765 bp of the 18s gene of the plasmodium genome were amplified by classic pcr .
resulting products were sequenced either directly or after cloning for rrna gene and when initial sequence information showed the possible presence of 2 different species ( table ) . *
all chimpanzees were pan troglodytes verus from tai except p. t. schweinfuthii chimpanzees , which were from budongo forest .
parentheses indicate the number of samples for which sequences were obtained and used for phylogenetic tree analyses .
phylogenetic analyses of sequences obtained confirmed the presence of 5 species : p. reichenowi and p. gaboni , which had been found previously ( 2,3 ) ; but also p. vivax , p. ovale , and p. malariae like strains ( figure 1 , figure 2 ) .
the most prevalent species was p. reichenowi ( 6/16 ) , which had representatives in subclusters p. gaboni and p. reichenowi .
the other species were rare , seen only 1 ( p. ovale and p. vivax ) or 2 ( p. malariae ) times .
( figure 1 , figure 2 ) , 1 infected with p. reichenowi and a p. malariae like strain and the other with p. reichenowi and p. gaboni .
maximum - likelihood trees of plasmodium spp . obtained from the analysis of a 1,087-bp cytb alignment .
blue indicates sequences determined from chimpanzee hosts ; green , bonobos ; gray , gorillas ; and red , humans .
blue indicates sequences determined from chimpanzee hosts ; green , bonobos ; gray , gorillas ; and red , humans .
typical for wild chimpanzees or related to reduced immune function associated with the severe infection that was the primary cause of death in each case ? to investigate this question , we tested dna extracted from fecal samples of apparently healthy chimpanzees collected over the past 8 years ( n = 30 ) ( 11 ) of the same study population by using the generic real - time pcr followed by amplification of the cytb gene .
of these samples , 21 ( 70% ) were positive for plasmodium spp . by real - time pcr .
because of low copy numbers in feces , phylogentic analyses were limited to 2 samples in which p. reichenowi of the p. gaboni subcluster was confirmed . to determine if the observed high prevalence of plasmodia was a site- or chimpanzee subspecies specific phenomenon , we tested 30 randomly selected fecal samples of individually known apparently healthy wild eastern chimpanzees from the budongo forest in uganda . overall prevalence of plasmodium spp .
was lower than in west african chimpanzees but still relatively high ( 40% ) ; p. reichenowi and p. gaboni were identified in 3 samples .
is similar to that of untreated human populations in sub - saharan africa ( www.who.int/malaria ) . throughout sub - saharan africa ,
p. falciparum is more predominant in humans than are other plasmodium spp . considering the lack of clinical signs of malaria in chimpanzees from which fecal samples were collected and those that had died of respiratory disease or anthrax , plasmodium spp .
however , signs of illness are rarely observed in wild primates because infected animals often mask weakness to maintain social position and avoid attack by predators ( 12 ) .
recently developed technologies for the noninvasive determination of temperature in wild chimpanzees may enable more effective examination of the relationship between the primary clinical feature of malaria ( i.e. , cyclical fevers ) and plasmodium spp .
p. ovale was previously described from captive chimpanzees and p. malariae from captive chimpanzees and captive bonobos have been described ( 58 ) .
our study results demonstrate that p. malariae and p. ovale occur in wild chimpanzees that inhabit pristine contiguous forest with extremely limited exposure to humans , suggesting the natural existence of these parasites in wild great apes . because of a duffy - negative condition in 95%99% of the human population in western and central continental africa , transmission of p. vivax does not seem to occur
. however , p. vivax infections are common in travelers returning from these areas ( 11 ) .
even though we can not totally exclude the possibility of introduction of p. vivax in the chimpanzee population through humans , our discovery of p. vivax in wild chimpanzees living exclusively within their natural habitat suggests that wild african apes may be a natural reservoir .
our study shows the existence of p. reichenowi and related strains in wild chimpanzees as described for chimpanzees and gorilla by others ( 24,6 ) .
infections with strains of the p.
reichenowi group ( sometimes referred to as the species p. gaboni , p. billbrayi , and p. billcollinsi ) appear to occur widely in wild and captive great apes in africa with some variation between chimpanzee subspecies from biogeographically distinct sites .
this lack of infection is likely caused by low human presence in their habitat and , consequently , few or no infected vectors , low sample size , or a missing receptor in chimpanzees ( 14 ) .
more investigations are needed because recently p. falciparum infections have been described for 2 captive chimpanzees ( 6 ) .
the situation is clearer for captive and wild lowland gorillas ( gorilla gorilla ) for which infections and receptors have recently been described ( 4 ) .
previous examination of the role of our closest phylogenetic relatives , the great apes , in the evolution and persistence of human plasmodia has been limited by a lack of data from wild ape populations where opportunities for human - mosquito - ape malaria exchange are minimal .
interpretation of patterns of malaria infection in captive ape populations , such as sanctuaries and zoos , must consider the ample opportunities for human - to - ape transmission of such parasites , negating the opportunity to investigate the evolutionary origins and public health related risks of these parasites .
conversely , our examination of these parasites in wild chimpanzees with no contact to the periphery of the rainforest habitat ( technical appendix figure ) demonstrates that these apes are most likely naturally infected with p. ovale , p. vivax , and p. malariae , 3 types of plasmodia rarely observed in humans of the region . whether wild great apes are the origin or reservoirs of these plasmodium types requires further investigation .
these results may have implications for global efforts to eradicate malaria in humans , including vaccine development based on animal variants of human parasites .
Output:
| data are missing on the diversity of plasmodium spp . infecting apes that live in their natural habitat , with limited possibility of human - mosquito - ape exchange .
we surveyed plasmodium spp .
diversity in wild chimpanzees living in an undisturbed tropical rainforest habitat and found 5 species : p. malariae , p. vivax ,
p. ovale , p. reichenowi , and p. gaboni . |
PubmedSumm6574 | ***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: eccrine poroma is a benign neoplasm of the sweat glands originating from the intraepidermal eccrine duct.1 ) this unusual tumor is known to arise in bare skin areas , such as the sole of the foot .
recently it was revealed that it could occur in more various skin region.2 ) but only few cases have been reported in the head and neck area .
a 54-year - old female presented with a gradually increasing mass on the auricle for one year . on physical examination , there was a soft , protruding , and purple - colored , solitary mass , 1.01.0 cm in size on the retroauricular surface of the left auricle ( fig .
the patient reported serous discharge but there was no pain nor tenderness . with an impression of an atypical nevus or a melanoma
histopathological findings revealed that broad anasto - mosing bands extended from the epidermis to dermis with multifocal fibrovascular cores and irregular duct - like structures ( fig .
there were also tightly packed small uniform cells with central round to oval nuclei , prominent nucleoli , and occasional clear cytoplasm ( fig .
we did not find any necrosis , nuclear atypia , or mitosis in the specimen .
after complete excision , the patient has been followed up without any recurrence for more than 6 months .
eccrine poroma was first described by goldman , et al.2 ) in 1956 as a neoplasm composed of cells that are analogous to cells in the walls of eccrine sweat pores .
it is composed of poroid cells and cuticular cells that have much eosinophilic cytoplasm , similar to eccrine ductal cuticles.1 ) vacuolizations in the intracytoplasmic and intercellular areas are characteristic histological features , resembling the formation of eccrine ducts.1 ) this tumor is occurred in bare areas of skin such as the sole of the foot .
goldman , et al.2 ) reported that the most common sites were soles of feet ( 65% ) followed by the hands ( 10% ) .
only one case of the ear ( external auditory canal ) has been previously reported , and only three cases reported in the postauricular scalp skin , not on the auricle worldwide . among seven cases reported in the korean literature ,
the scalp was the most common site.3,4,5,6 ) moore , et al.7 ) compared patients with poroma in the head and neck area with lesions occurred in extremities .
lesions of the head and neck were mostly asymptomatic mass , but some patients with poroma in the extremities complained symptoms such as pain or discharge . and more pigmented lesions were noted in the head and neck , compared with mass of the extremities . in our case ,
histopathological diagnosis is crucial because eccrine poroma should be differentiated from basal cell carcinoma and seborrheic keratosis.3 ) poroma seems to have more organoid appearance than basal cell carcinoma . also , poroma has fewer epithelial cells compared to the seborrheic keratosis of the sweat duct .
it has been found that about 18% of poromas transform to procarcinoma.8 ) in a case of reported malignancy , it causes multiple cutaneous metastases leading to death.4 ) porocarcinoma shows more exphytic and ulcerative appearance than eccrine poroma .
when the eccrine poroma develop into malignancy , it shows spontaneous bleeding , ulceration , sudden itching sense or pain , and rapid growth in a short period.8 ) so early detection , complete excision and close follow up are important in the management of the tumor .
Output:
| eccrine poroma is described as a benign neoplasm originating from the intraepidermal eccrine duct of sweat glands .
this tumor is known to arise in bare skin areas , but more rarely appeared in head and neck region . a 54-year - old female presented with a mass on the retroauricular aspect of the left auricle .
there was a soft , protruding , and purple - colored , solitary mass of about 1.01.0 cm in size .
after authors performed an excisional biopsy , eccrine poroma was confirmed histopathologically .
thus , we report a rare case of eccrine poroma of the ear with the review of literature . |
PubmedSumm6575 | ***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: uncomplicated and complicated crown fracture is the most common traumatic dental injury to permanent teeth .
most dental injuries involve just one tooth , and the majority of the affected teeth are maxillary central incisors.[24 ] this may be attributable to their anterior position and protrusion caused by the eruptive pattern . during the last century
, clinicians used a variety of procedures ( e.g. , pin - retained resin , orthodontic bands , modified three - quarter crowns , full - coverage gold with bonded porcelain , porcelain jacket crowns , porcelain - bonded crowns , porcelain inlays ) for the restoration of the fractured crown .
several factors influence the management of coronal tooth fractures , including extent of fracture ( biological width violation , endodontic involvement , alveolar bone fracture ) , pattern of fracture and restorability of fractured tooth ( associated root fracture ) , secondary trauma injuries ( soft tissue status ) , presence / absence of fractured tooth fragment and its condition for use ( fit between fragment and the remaining tooth structure ) , occlusion , aesthetics , finances and prognosis.[79 ] if the fracture is uncomplicated ( i.e. , not involving the pulp ) and the pulpal health is uncompromised , it may be restored with composite resin or a jacket crown . if the pulp is involved , the tooth is treated endodontically and then restored with the help of a jacket crown with or without post and core . if the fracture is sub - gingival , the tooth may require surgical crown lengthening or forced eruption ( orthodontic extrusion ) followed by prosthetic rehabilitation . in situations where a ferrule effect can not be established , the only treatment left is the extraction of the tooth followed by prosthetic rehabilitation .
one of the options for managing coronal tooth fractures , especially when there is no or minimal violation of the biological width , is the reattachment of the dental fragment when it is available .
tooth fragment bonding offers the advantage of being a highly conservative technique that promotes preservation of natural tooth structure , good aesthetics and acceptance by patients , who receive a psychological benefit from amelioration of the mutilation .
a 13-year - old boy reported to the department of pedodontics and preventive dentistry with a history of fall from cycle 2 days back .
clinical and radiographic examination revealed ellis class iii fracture ( involvement of enamel and dentin compromising the pulp ) of the maxillary left central incisor [ figure 1 ] .
an intraoral periapical radiograph was taken , which showed the coronal fracture with no root fracture or any other periapical changes [ figure 2 ] .
the child was carrying the broken tooth fragment that was confirming adequately to the fractured left central incisor [ figure 3 ] .
the tooth fragment was stored in water and did not show any significant change in color .
ellis class iii fracture of the maxillary left central incisor intraoral periapical radiograph showing coronal fracture the fractured fragment an immediate endodontic intervention followed by bonding of the fractured segment using the acid etch technique was decided .
an access cavity was prepared and pulp extripation was performed with the help of barbed broaches . after working length determination ,
biomechanical preparation was carried out with the help of k - files using the crown down technique .
copious irrigation of the root canal was intermittently done with sodium hypochlorite and normal saline .
the canal was dried with absorbent point and was obturated with gutta percha points and zinc oxide eugenol sealer using the lateral condensation technique [ figure 4 ] .
the tooth fragment was disinfected with sodium hypochlorite solution and then rinsed properly with water .
an enamel bevel was prepared all around the remaining tooth structure as well as the fractured margin of the segment and the fragment was reapproximated to check its fit [ figure 5 ] .
an additional internal dentinal groove was also prepared within the dentine of the fractured fragment part , which approximated the access cavity prepared for endodontic therapy of the remaining tooth structure [ figure 6 ] .
acid etching of the access cavity and the approximating surfaces of the two segments were carried out for 20 s with 37% orthophosphoric acid [ figure 7 ] .
amherst , ny , usa ) was subsequently applied and light cured for 10 s. the access cavity was filled with composite resin in small increments and light cured for 40 s for each increment .
then , flowable composite ( ( ivoclar vivadent inc , usa ) was applied into the dentinal grove and on the approximating surfaces of the fragment and the remaining tooth .
both the fragments were reapproximated and light cured for 40 s each from the buccal and lingual aspects of the tooth .
flowable composite was applied over the bevel all around the tooth and was light cured appropriately . finishing and polishing of the tooth
the patient came for recall visit at 3 months , 6 months and 18 months and the tooth was found to be intact and functional inside the oral cavity in all the three visits .
intraoral periapical radiograph showing the endodontic intervention circumferential enamel bevel internal dentinal groove post - treatment : reattached tooth fragment
the treatment performed and presented in this clinical case report is one of the many possible options that could have been used to rehabilitate this patient .
the other treatment options may have included the endodontic therapy followed by restoration of the tooth with composite resin or with a full coverage crown .
selection of the treatment plan should be made considering the advantages and disadvantages of each technique available and should be in conjunction with the desires and limitations of the patient . restoration with composite resin with the help of the acid etch technique is considered to be a highly aesthetic treatment for restoring fractured anterior teeth . although composite resins do not have hydroxyapatite crystals , dentin tubules or enamel rods , these newer formulations possess secondary optical properties such as translucency , opacity , opalescence , iridescence , fluorescence and surface gloss .
there is , however , no synthetic restorative material that can replicate the aesthetic characterization or color stability of the natural tooth structure .
moreover , composite resin will be abraded more quickly than enamel by the opposing dentition .
in contrast to this , when the fractured tooth fragment is reattached , the rate of wear and abrasiveness is the same as that for the intact tooth .
in addition , the treatment procedure is less time - consuming ; thus , cutting the cost of the treatment .
reattachment of the original tooth fragment also gives an emotionally and socially positive response due to the protection of the natural tooth structure .
the patient and parents are at least satisfied of the original fragment being used in the restoration of their fractured tooth .
various authors have recommended extra preparation of the fractured fragment and the remaining tooth structure to enhance the bonding of the fractured fragment to the remaining tooth .
they pointed out that when reattaching without making any extra preparation for the broken incisal part and for the remaining tooth in the mouth , lower values than intact tooth fracture strength were obtained .
therefore , they stated the necessity of the application of an extra preparation on the tooth when reattaching the broken incisal part . in the case presented here , a combination of external enamel groove ( bevel ) in the shape of a v at the fracture interface and
an internal dentinal grove has been used to enhance the bonding of the fragment with the remaining tooth .
the patient was followed - up for 18 months and the results were found to be satisfactory , both aesthetically and functionally . in a similar manner , bruke had used a combination of an internal dentin groove and the circumferential beveling of enamel margins and found the result to be successful .
other additional preparations that have been used by different clinicians to improve adhesion between the fractured and the remaining segment include placing a chamfer at the fracture line after bonding , using a v - shaped enamel notch and placing an internal groove or a superficial overcontour over the fracture line . in cases where the patient is undergoing fixed orthodontic treatment or is likely to undergo fixed orthodontic treatment in the near future
, the reattachment technique allows performing such treatment and seems to be advantageous and reliable as reported by simonsen .
the present literature shows good short - term and medium - term results of this technique .
very often , the loss of the reattached fragment occurs due to another traumatic injury to the treated tooth , non - physiological use of the tooth or horizontal traction when biting into hard and chewy foods .
thus , andreasen et al . suggested fabrication of a mouth guard and patient education about the precautions and treatment limitations of this procedure . in young patients and adolescents , where a prosthetic rehabilitation or an implant is indicated but is limited by their age , reattachment may be carried out as a provisional restoration or treatment . in those cases , if the patient could benefit from the restoration for some years before receiving a more complex and expensive
Output:
| reattachment of the fractured anterior tooth is a highly conservative and aesthetic treatment that has gained popularity in the recent past .
presented here is one such case in which a combination of external enamel bevel and internal dentinal groove has been used to enhance the bonding between the fractured fragment and the remaining tooth .
the treatment was found to be successful both functionally and aesthetically at the 18-month follow - up . |
PubmedSumm6576 | ***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: neuropeptide y ( npy ) is one of the most common peptides in the brain and an abundant neurotransmitter in the peripheral sympathetic nervous system ( sns ) .
it plays a well - established role in the hypothalamic control of body energy balance by promoting feeding and lipid storage in white adipose tissue ( wat ) .
however , in pair - fed rats , central npy administration still leads to increased fat accumulation , which suggests that npy has an important role in promoting adiposity independent of food intake .
npy outside the hypothalamus in the regulation of energy homeostasis has not been widely studied , although npy and its receptors are located in key peripheral tissues , such as wat , liver , and pancreas .
npy inhibits lipolysis in adipocytes via y1 receptors , and could modulate adipose tissue expansion by regulating angiogenesis .
npy also inhibits insulin release via pancreatic y1 receptors . on the other hand , npy in the brainstem
could modulate sympathetic tone , which is known to have multiple effects on energy homeostasis .
to address the role of npy colocalized with noradrenaline in sns and brain noradrenergic neurons , we created a transgenic mouse model ( oe - npy mouse ) , where npy is overexpressed under the dopamine - betahydroxylase ( dbh ) promoter .
this resulted in moderately increased levels of npy protein ( 1.31.8-fold ) peripherally in adrenal glands and centrally in noradrenergic neurons of the brainstem , but not in the hypothalamus .
the oe - npy mice displayed increased adiposity and liver triglyceride accumulation without changes in body weight , food consumption , or physical activity on a normal chow diet .
the increased adiposity was observed in both genders at all ages studied , but the major metabolic complications such as impaired glucose tolerance , hyperinsulinemia , and hepatosteatosis were only present in male oe - npy mice .
furthermore , the oe - npy mice showed elevated sympathetic tone and increased responses to stress , and increased susceptibility to arterial thickening after vascular injury .
others have shown that stress - induced activation of the npy system combined with a high - calorie diet results in augmented obesity .
the primary finding of kuo et al . was increased fat mass without change in food intake or body weight after two weeks of daily stress and high fat diet
. prolonged stress and diet led to liver steatosis , impaired glucose tolerance and obesity , which were attenuated by local y2r antagonist administration and fat - targeted y2-gene knockdown procedure .
these data combined show that extrahypothalamic npy regulates adiposity independent of food intake and that npy together with stress are potent factors in several pathways leading to a complex disorder called the metabolic syndrome . in humans ,
association studies of a polymorphism in the npy gene have linked npy to metabolic disturbances .
the npy1228 t > c polymorphism ( rs16139 ) , which causes an amino acid substitution of leucine 7 to proline 7 ( l7p ) in the signal peptide is functional , enhancing the secretion of npy [ 10 , 11 ] .
it is associated with an earlier onset of type 2 diabetes in carriers of l7p , as well as with other traits of the metabolic syndrome especially in obese subjects .
recently , it was reported that there is a gender difference in the npy - mediated effects of the proline 7 allele .
the associations of the l7p seem to be more pronounced in men than women , which is in agreement with our findings in oe - npy mice indicating that males develop more severe metabolic changes .
human obesity and metabolic syndrome are often due to lifestyle changes including increased sedentary work and decreased physical activity , and increased accessibility and affordability of dense , high - calorie foods .
an increase in dietary fat and sucrose content has been shown to produce hyperglycaemia and obesity in various strains of mice and rats . in the present study
, we exposed male and female oe - npy and wildtype ( wt ) control mice to an energy - dense western - type diet for seven weeks , and compared the genotype and sex differences in the impacts of the diet on the development of obesity , insulin resistance , and impaired glucose tolerance . based on the findings in these mice ,
the possible reasons , that is , food intake and physical activity , were studied further in the oe - npy female mice .
eight - week - old male and female oe - npy mice heterozygous for the npy transgene and their wt littermates on a c57bl/6n genetic background were used .
animal care was in accordance with the guidelines of the european convention for the protection of vertebrate animals used for experimental and other scientific purposes ( council of europe no .
123 , strasbourg 1985 ) , and all experimental procedures were approved by the institutional animal care and use committee .
oe - npy mice are stress - sensitive , and therefore the mice in this study were housed with their same - sex siblings instead of single cages and maintained on a 12-h light / dark cycle ( lights on at 6 am ) with free access to food and water .
the number of animals in the male groups was 9 - 10 , and in the female groups 15 - 16 .
the mice were placed on a western - type diet ( 42% kcal fat from milk fat , 43% carbohydrates from sucrose and corn starch , 15% protein , and 0.15% supplementary cholesterol , code 829100 , special diets services , essex , uk ) and fed ad libitum for seven weeks .
after five weeks on the diet , the mice were fasted from 6:00 h to 10:00 h , and administered intraperitoneally ( ip ) with glucose ( 10% w / v , 1 g kg body weight ) for glucose tolerance test ( gtt ) .
tail vein blood glucose was measured immediately before the injection and at 20 , 40 , 60 , and 90 min with a glucose analyzer ( precision xtra , abbott diabetes care , abbott park , il , usa ) .
areas under the resultant curves ( auc ) were calculated with the trapezoidal method in graphpad prism 5.01 software .
mmol l ( 250 mg dl ) in mice following a fast started on the morning of the experiment as guided by mouse metabolic phenotyping centers ( http://www.mmpc.org/ ) established by the national institutions of health ( nih ) and by the animal models of diabetic complications consortium ( amdcc , http://www.amdcc.org/ ) .
the same level of fasted blood glucose in determination of hyperglycaemia in mice has been used by others as well [ 16 , 17 ] .
after six weeks on the diet , the mice were fasted for 1 h. recombinant human insulin ( protaphane , novo nordisk ) at a dose of 0.5 or 1.0 iu kg was injected ip for insulin tolerance test ( itt ) .
blood glucose was measured immediately before the injection and at 20 , 40 , and 60 min after the injection . at sacrifice ,
the mice were fasted from 6:00 h to 10:00 h , the rectal temperature was measured ( ellab , roedovre , denmark ) , and the animals were anesthetized with ketamine ( ketalar 75 mg kg ) and medetomidine ( domitor 1 mg kg ) .
terminal blood samples were obtained from inferior vena cava with 1 ml syringe and 23 g needle into heparinized tubes .
plasma was centrifuged ( 4000 rpm , 10 min ) and stored at 70c until analyzed .
wat weight was determined by collecting the subcutaneous , epididymal / gonadal , and retroperitoneal fat pads .
in addition , brown fat and liver weights were determined , and the tissues were snap frozen in liquid nitrogen for further analyses .
brown fat samples were cryo - sectioned on microscopic slides and stained with hematoxylin and eosin ( h&e ) for standard morphology .
plasma concentrations of insulin ( mercodia ultrasensitive mouse insulin elisa , mercodia ab , uppsala , sweden ) and total cholesterol ( biovision cholesterol quantitation kit , biovision inc .
, mountain view , ca , usa ) were determined according to the manufacturers ' instructions . total rna in bat
was extracted with trizol reagent ( invitrogen , carlsbad , ca , usa ) combined with dnase treatment ( turbo dna - free kit , ambion inc . ,
rna was converted to cdna with high capacity rna - to - cdna kit ( applied biosystems ) according to the manufacturer 's instructions .
predesigned taqman gene expression assay ( applied biosystems , assay i d mm01244861_m1 ) for uncoupling protein-1 ( ucp-1 ) was used to analyze the mrna levels in bat .
ucp-1 levels were quantitated relatively to the housekeeping gene -actin , ( mouse actb , vic / mgb probe , primer limited with 7300 real - time pcr system applied biosystems ) .
relative ct method and the formula 2 were used as the quantitation method . in order to study the genotype differences in the female gender in more detail , another set of female mice age - matched to experiment 1 were studied .
this time we used oe - npy mice homozygous for the transgene and c57bl/6n wt female mice .
heterozygous oe - npy mice were bred together in order to produce wt , heterozygous and homozygous pups , which were genotyped by qpcr .
genomic dna was isolated from tail biopsies with a commercial kit ( puregene dna purification kit , gentra , minneapolis , mn , usa ) . forward
( 5-tggctggagtgcgatcttc-3 ) and reverse ( 5-gagtttgaccgtctacgtgc-3 ) primers , and the taqman - mgb probe ( 6fam - ccgatactgtcgtcgtc - mgb ) were designed for the lacz reporter gene in the transgene construct with the primer express 3.0 software ( applied biosystems ) .
lacz levels were quantitated relatively to the housekeeping gene -actin , ( mouse actb , vic / mgb probe , primer limited ) .
homozygous oe - npy and littermate wt mice were selected for breeding ( oe - npy oe - npy and wt wt ) , thus creating purely transgenic or wt lines housed separately .
the first litters from the homozygous and wt mouse lines were genotyped as described above to verify all pups had the same genotype for the transgene .
the female mice ( n = 712 ) were placed on the western - type diet for five weeks and their weight gain and food consumption were measured on a weekly basis .
in addition , after two weeks on the diet , a 24-h spontaneous physical activity along with food intake was monitored with a photo - beam recording system ( san diego instruments , san diego , ca , usa ) in 10 minute intervals .
mice were placed in single cages and had a 23-h adjustment period before monitoring the 24-h activity .
whole body fat mass was measured in vivo after the five - week period with an echomri-700 ( echo medical systems , houston , tx , usa ) .
the reproduction history of all three genotype lines was followed and the number of total pups as well as female versus male pups was analyzed .
the number of wt , heterozygous oe - npy , and homozygous oe - npy dames used in breeding was 45 , 26 , and 34 , respectively .
the results were analyzed with a student 's parametric t - test or with a mann - whitney 's nonparametric u - test to compare the groups of oe - npy and wt mice .
weight gain , gtt and itt were analyzed with two - way anova for repeated measurements and bonferroni posthoc tests .
test was used to calculate the statistical difference in the number of male mice with hyperglycaemia as 0 = fasting glucose
< 13.8 mmol l or 1 = fasting glucose > 13.8 mmol l. statistical analyses were carried out using graphpad prism 5.01 ( graphpad software , san diego , ca , usa ) .
female oe - npy mice gained more weight compared with their wt littermates on the western diet ( figures 1(a ) and 1(c ) ) . in males ,
prominent weight gain was observed in both genotypes , but no difference in the weight gain pattern was observed between the oe - npy and wt mice ( figures 1(b ) and 1(d ) ) .
the female transgenic mice also had larger wat and bat mass as measured by individual fat pads or the sum of wat pads compared with wt female mice ( figures 1(e ) and 1(g ) ) . in males , a significant difference between the genotypes was only observed in the epididymal wat weight ( figures 1(f ) and 1(h ) ) .
glucose tolerance was significantly impaired in female oe - npy mice compared with wt mice , as shown by the much greater rise in blood glucose in oe - npy mice over the studied 90 min time period following administration of glucose ( figure 2(a ) ) .
in addition , the auc value in oe - npy mice was significantly higher than in wt controls ( table 1 ) .
in male mice , the glucose tolerance was similar between the genotypes and thus no statistical significance between the groups was reached ( figure 2(b ) ) .
however , four out of ten oe - npy male mice , but none of the nine wt controls , had a 4-h fasting glucose value over 13.8 mmol l. thus , they were considered to show severe hyperglycaemia [ 16 , 17 ] .
this difference reached statistical difference of p < 0.05 with the test .
there was no difference in gtt auc values between the genotypes in males ( table 1 ) .
insulin sensitivity was assessed by investigating the action of exogenous insulin on blood glucose levels .
blood glucose levels were higher in female oe - npy mice compared with their wt controls at all investigated time points after intraperitoneal injection of insulin ( figure 2(c ) ) .
insulin was first administered with 0.5 iu / kg , which was sufficient in females but had no effect on circulating glucose levels in males .
hence , the experiment was repeated with a higher dose of 1.0 iu kg .
this dose decreased blood glucose on average by 35% in eight out of nine wt and seven out of ten oe - npy male mice ( figure 2(d ) ) , whereas the rest of the mice ( 1/9 of wt and 3/10 of oe - npy ) were resistant to the effect of insulin , that is , the blood glucose levels were the same or even higher than at baseline .
no significant difference between the genotypes in blood glucose values after insulin dosing in males was observed . circulating insulin and total cholesterol levels were determined after a 4-h fast .
no difference in either parameter was observed between the genotypes in males or females ( table 1 ) .
the female oe - npy mice had significantly heavier livers per se ( wt : 1.1 0.07 ; oe - npy : 1.3 0.06 grams ; p < 0.05 ) , but when the weights were corrected with body weights , the statistical difference was lost ( data not shown ) . in males ,
the actual ( wt : 2.5 0.21 ; oe - npy : 2.8 0.22 grams ; p = ns ) and normalized liver weights were identical between the genotypes .
gross visual examination of the livers suggested steatosis as observed by a pale abnormal color with naked eyes .
no difference in triglyceride levels between the genotypes in males or females was observed ( table 1 ) .
rectal body temperatures did not differ between the genotypes in males ( wt : 35.4 0.24 ; oe - npy : 35.7 0.29 degrees centigrade ) or females ( wt : 35.9 0.36 ; oe - npy : 35.7 0.37 degrees centigrade ) .
ucp-1 expression levels in bat were measured with qpcr by using the average mrna expression of the wt group as a calibrator .
no difference in ucp-1 levels in males ( wt : 1.13 0.18 ; oe - npy : 1.16 0.15 fold mrna expression ; p = ns ) or females ( wt : 1.09 0.13 ; oe - npy : 1.24 0.16 fold mrna expression ; p = ns ) were observed .
the tissue morphology showed atypical bat tissue with lipid deposition in both male groups and in the oe - npy female group whereas the wt females showed normal bat morphology ( figure 3 ) . in order to verify and to find the reason for the findings in females , the early steps of the weight gain and adiposity were further studied in a homozygous oe - npy line .
a similar weight gain pattern was observed as in the heterozygous mice in comparison with wt controls , that is , the weights start to differ after four weeks on the diet and are significantly higher at five weeks from the beginning of the diet ( figure 4(a ) ) .
food intake measured weekly in group - housed ( food consumed divided by the number of animals ) ( figure 4(b ) ) or in 47-h individually housed mice ( wt : 6.7 0.7 ; oe - npy : 6.3 1.2 grams ; p = ns ) was not different between the genotypes .
a whole body echomri analysis was performed at week five to measure the amount of fat in vivo .
the oe - npy females showed increased adiposity compared with wt mice ( figure 4(c ) ) , which explains the difference in body weights .
24-h locomotor activity of female wt and oe - npy mice measured in photo - beam cages after two weeks on the diet revealed no differences between the genotypes either in horizontal or vertical movements ( data not shown ) .
total activity per hour calculated as the sum of these two parameters is presented in figure 5 .
based on 82 litters from 45 wt dames , wt female mice produced on average 3.5 female ( total 284 ) and 3.6 male ( total 294 ) pups .
heterozygous oe - npy female mice ( 35 litters from 26 dames ) produced 4.0 female ( total 141 ) and 3.8 male ( total 134 ) pups and homozygous oe - npy mice ( 55 litters from 34 dames ) 3.3 female ( total 176 ) and 3.7 male ( total 199 ) pups .
in our previous work , we observed that both the male and female transgenic mice overexpressing npy in noradrenergic and adrenergic neurons showed increased adiposity without significant increase in body weight or food intake on a normal chow diet . in the current study , we hypothesized that npy overexpression would render the transgenic mice even more susceptible to obesity induced by a western - type diet . in line with the hypothesis ,
the female oe - npy mice gained significantly more weight compared to their wt littermate controls ( 40% versus 26% of initial weight ) and showed an increased adipose tissue mass .
in contrast , the male oe - npy mice gained weight similarly to their wt controls ( 55% of initial weight ) .
thus , npy overexpression overrode the resistance of the c57bl/6 female mice to the diet - induced obesity , but susceptibility of the male c57bl/6 mice to the diet induced obesity overrode the npy 's adiposity inducing effect
. the mechanisms of increased weight gain in the female oe - npy mice were studied in more detail in a separate group of mice .
this time the mice were homozygous for the transgene and thus housed with same - sex , same - genotype siblings , which made it possible to study the feeding behavior between the genotypes in unstressed conditions ( group housing ) .
the results showed that enhanced weight gain is not due to increased food consumption during the time preceding the difference in body weights .
rodents resistant to the diet - induced obesity increase bat thermogenesis via increased ucp-1 activity to avoid weight gain .
similar to the oe - npy and wt male mice , the female oe - npy mice showed atypical bat morphology with white fat - like appearance and large lipid vacuoles in bat .
this implied the onset of brown adipocyte degeneration often associated with obesity and impaired thermogenesis in mice [ 20 , 21 ] .
however , the bat thermogenic capacity , as measured by ucp-1 expression levels in bat , did not differ between the genotypes .
we show in this study that there are no differences in the number of litters or litter sizes between the oe - npy or wt mice .
thus , prenatal and suckling conditions in this regard are similar for the pups . therefore , different challenges in the developmental and prepubertal environment are an unlikely explanation for the weight gain in the diet - induced obesity in the oe - npy mice .
sexually dimorphic responses to npy - associated metabolic changes have been reported in npy y1 receptor knock - out mice , which develop late - onset obesity without hyperphagia that is more pronounced in female than male mice .
the difference was attributed to decreased skeletal muscle mitochondrial oxidative capacity in female y1 knock - out mice .
gonadal steroid hormones seem to play a role in the fat accumulation in the y1 knock - out mice as weight gain does not start until puberty [ 24 , 25 ] .
estrogens seem to protect female mice from obesity as evidenced for instance by weight gain after gonadectomy , and their effects are at least in part mediated by hypothalamic npy [ 26 , 27 ] .
our results may imply that the overexpression of npy in adrenergic and noradrenergic neurons overrides the protective effects of estrogens in female mice , suggesting that npy in the brainstem and in the sns may also play a role in mediating estrogen action on body composition .
along with the increased adiposity , the oe - npy female mice displayed impaired glucose tolerance and altered insulin sensitivity or counterregulatory effect of glucose 40 min after the ip administration of glucose .
it is generally acknowledged that female mice are less likely to develop disturbances in glucose metabolism , which may be due to the antiobesity effects of estrogens in females [ 29 , 30 ] .
previously , chow - fed female oe - npy mice were shown to possess normal glucose tolerance despite of increased adiposity and sensitivity to stress [ 6 , 7 ] , and impairment in glucose tolerance in the current study occurred with increasing levels of obesity .
thus , disturbances in glucose metabolism in the female oe - npy mice seem to be caused by increased adiposity rather than by direct effects of npy or sympathoadrenal system on glucose metabolism , which is supported by a positive correlation with the area under the curve value for gtt and body weight in both female genotypes ( wt , r = 0.54 , p < 0.05 ; oe - npy , r = 0.45 , p = 0.08 ) .
in contrast , the diet - induced hepatosteatosis that similarly affected the wt and oe - npy mice is not likely to explain the impaired glucose tolerance in the female oe - npy mice .
however , increased glycogenolysis in the liver in response to the insulin - induced decline may be responsible for the altered insulin sensitivity presented in figure 3(c ) , which remains to be studied further . although gtt showed very high levels of blood glucose with no genotype differences in the male mice , the oe - npy mice had a tendency towards reduced insulin - induced decline in glucose levels as evidenced by the more numerous individuals that did not respond to insulin in itt .
in addition , forty per cent of the oe - npy males but none of the wt littermates developed severe hyperglycaemia defined as a blood glucose level over 13.8 mmol l following a 4-h fast .
interestingly , these tendencies occurred without major differences in wat depot weights or at the level of hepatosteatosis in the oe - npy male mice .
this suggests that increased npy may have a diabetogenic effect in the context of obesity and supports the association of the l7p polymorphism with an earlier onset of diabetes in the obese human population .
oe - npy female mice showed a more pronounced diet - induced obesity , glucose intolerant , and insulin resistant phenotype on a western - type energy - dense diet than their wt littermates that could not be explained by increased feeding , decreased activity , or impaired thermogenesis .
this suggests that increased npy release may predispose women and females in general , to a greater risk of weight gain under high caloric conditions .
in contrast , there was no difference between the male oe - npy and wt mice in the degree of obesity , although the oe - npy mice seemed to be more susceptible to developing diabetes while on the diet .
interestingly , we have shown that the oe - npy males fed with chow and the oe - npy females with a western diet display similar traits with the humans who carry the proline 7 allele in their npy sequence , which support the associations between the rs16139 polymorphism and high npy levels and various metabolic risks .
furthermore , these results strengthen the hypothesis that npy has an important role in promoting adiposity via extrahypothalamic pathways .
Output:
| neuropeptide y ( npy ) is a neurotransmitter associated with feeding and obesity .
we have constructed an npy transgenic mouse model ( oe - npydbh mouse ) , where targeted overexpression leads to increased levels of npy in noradrenergic and adrenergic neurons .
we previously showed that these mice become obese on a normal chow .
now we aimed to study the effect of a western - type diet in oe - npydbh and wildtype ( wt ) mice , and to compare the genotype differences in the development of obesity , insulin resistance , and diabetes .
weight gain , glucose , and insulin tolerance tests , fasted plasma insulin , and cholesterol levels were assayed .
we found that female oe - npydbh mice gained significantly more weight without hyperphagia or decreased activity , and showed larger white and brown fat depots with no difference in ucp-1 levels .
they also displayed impaired glucose tolerance and decreased insulin sensitivity .
oe - npydbh and wt males gained weight robustly , but no difference in the degree of adiposity was observed . however , 40% of oe - npydbh but none of the wt males developed hyperglycaemia while on the diet .
the present study shows that female oe - npydbh mice were not protected from the obesogenic effect of the diet suggesting that increased npy release may predispose females to a greater risk of weight gain under high caloric conditions . |
PubmedSumm6577 | ***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: prions are infectious proteins , able to propagate and transmit the infection from one individual to another without an essential nucleic acid .
in addition to this horizontal transmission , typical of the mammalian transmissible spongiform encephalopathies ( tses ) , prions of fungi also transmit the infection vertically ( to their offspring ) , and so they are proteins acting as genes , just as nucleic acids can act as enzymes ( table 1 ) .
prions of mammals , yeast and the filamentous fungus podospora anserina most prions are amyloids filamentous polymers high in -sheet structure , usually protease resistant and with characteristic staining properties .
prion transmission occurs when donor amyloid enters the recipient cell and the equivalent recipient protein joins to the ends of the amyloid filaments , which act as a structural template , so that the recipient protein adopts ( usually ) the same conformation as the donor amyloid .
the known prion - forming proteins of yeast and mammals are listed in table 1 .
a single prion protein sequence can form any of several biologically distinct prion ' strains ' or ' variants ' , differentiated in mammals by incubation time , disease signs and lesion distribution , or in yeast by prion stability , phenotype intensity or sensitivity to elevated or depressed levels of particular chaperones ( reviewed in ) .
different prion variants have different amyloid structures , although the exact structures are as yet unknown .
prions that are fully infectious between individuals of the same mammalian or yeast species may transmit poorly or not at all between species , a phenomenon called the species barrier . in spite of centuries of exposure ,
sheep scrapie is not known to have been transmitted to humans , but bovine spongiform encephalopathy ( bse ) has ( fortunately only rarely ) done so .
the primary determinants of the species barrier are the sequences of the potential prion proteins of the two species . however , the prion variant is also an important factor .
for example , the ure2 nitrogen regulation proteins of various saccharomyces species can become prions ( called [ ure3 ] ) , and species barriers are seen among these [ ure3]s that are dependent on the prion variant . while one variant of the [ ure3 ] prion of species a may transmit with 100% efficiency to species b , another variant may transmit with 0% efficiency between the same two species .
these phenomena can be explained by assuming that each sequence has a range of possible conformers .
a narrow overlap of conformers between donor and recipient produces a high species barrier , while a wide overlap implies a low barrier .
thus , according to this model , a specific conformer common to donor and recipient could overcome what would otherwise be a high species barrier .
it is likely that interactions with chaperones or other cellular factors , known to differ depending on prion variant , will be found to be at least part of some species barriers . in yeast ,
de novo formation of prions can , though rarely , be primed by other prions .
all of the prion - forming proteins of yeast have asparagine / glutamine - rich prion domains , and this shared structure is thought to enable prions of one of the proteins to prime filament formation by others .
in fact , de novo generation of the [ psi ] prion of saccharomyces cerevisiae is almost undetectable in a strain not carrying one of the other prions .
this cross - seeding produces an array of prion variants , whereas passing a species barrier usually produces a single , unchanged prion variant in the recipient . in both mammals and yeast ,
if a prion is successfully transmitted to a new host , the variant produced in the recipient is usually that of the donor .
for example , when zoo animals were infected with bse , and those infections were then introduced into mice , the same unique distribution of brain lesions was seen as when mice were infected with bse directly from cows .
similarly , passing the [ ure3 ] of one species through ure2p of a different species and then returning it to the original ure2p generally produces a [ ure3 ] prion 1 with the same properties as the original . in some cases ,
however , infection of a new species is so inefficient in other words , the species barrier is so high that disease only results if a ' mutant ' prion is selected that can replicate readily in the new host ( figure 1a ) .
for example , mouse scrapie strain 139a only produces disease in hamsters after an extended incubation period ( see , for example ) .
serial passage of the infection in hamsters then eventually produced a shorter stable incubation period .
however , on passage from hamsters back into mice and after the initial species barrier had subsided by a few passages , the agent had a dramatically longer incubation period than the original mouse scrapie and gave a different brain - lesion profile .
the conclusion from this classic experiment was that a ' mutant ' scrapie strain had been selected .
( a ) an altered form ( a ' mutant ' ) of mouse scrapie strain 139a is selected by the high species barrier encountered when it is transferred to hamsters ( modified from ) .
( b ) the species barrier between the s. cerevisiae sup 35 prion [ psi ] and a chimeric protein with a p. methanolica sup35 prion domain results in the rare generation of either of two [ chipm ] prion variants of the latter on exposure to [ psi ] .
( c ) schematic diagram showing partial templating by species a amyloid filament of species b protein .
species b protein sequence is incompatible with all of species a filament structure , and so assumes an altered self - propagating form a prion variant .
an apparently analogous phenomenon has recently been reported in bmc biology by vishveshwara and liebman using chimeric yeast prions .
the [ psi ] prion of s. cerevisiae is based on an amyloid form of the protein sup35p , which normally functions as a translation termination factor ( table 1 ) .
sup35p has a glutamine ( q)/asparagine ( n)-rich amino - terminal prion domain ( n ) the domain responsible for amyloid formation a charged middle domain ( m ) , and a carboxy - terminal domain ( c ) , which is responsible for sup35p 's normal function of translation termination . a chimeric protein made by fusing the similarly q / n - rich n domain and the m domain of sup35 protein of the yeast pichia methanolica to the s. cerevisiae c domain ( nmpm - csc )
will act as a prion , called [ chipm ] , when expressed in s. cerevisiae .
however , the considerable sequence difference between the p. methanolica and s. cerevisiae sup35 n domains results in a species barrier between the two n domains , so that prion transmission is rare . moreover , the rare prion transmission from [ psi ] to [ chipm ] results in at least two different prion variants of the chimera ( figure 1b ) .
this indicates that the s. cerevisiae sup35n amyloid was not able to accurately template the chimera , although its presence certainly induced prion formation by the chimeric protein . in this case , it was probably prion generation that was induced by [ psi ] , rather than transmission , although it remains possible that one of the [ chipm ] variants corresponds to the original [ psi ] variant .
the similarity between the scrapie ' mutation ' phenomenon and the yeast stimulated prion generation is striking . in each case , sequence differences largely blocked duplication of the donor prion conformation , resulting in only partial templating and generation of altered prion variants .
this also is presumed to be the basis of the prion priming phenomenon described above .
the structure of infectious prp is not yet known , but infectious amyloids of the prion domains of ure2p , sup35p and rnq1p each have an in - register parallel -sheet structure ( see , for example , ) .
thus , each residue of the last monomer to join the filament contacts the same residue of the preceding monomer ( figure 1c ) .
the register is maintained by hydrogen bonds between gln or asn ( the so - called -zipper ) and possibly between ser and thr residues .
a line of hydrophobic residues down the fiber will likewise have positive interactions , helping to keep the -sheet in register .
the location of turns , the contacts between -sheets and the extent of -sheet are thus transmitted to the newly joined monomer . combined with chain breakage to make new seeds ,
a weakly homologous or non - homologous ( but still q / n rich ) monomer might interact with part of the monomer on the end of the filament , so that only part of its conformation was fixed .
the remainder may form by some stochastic interaction with another monomer identical to itself ( shown schematically in figure 1c ) .
this could explain yeast prion cross - seeding and the ' mutation ' phenomena using the known structural information .
unlike the mammalian tses and the yeast prions [ ure3 ] and [ psi ] , which are all diseases , the [ het - s ] prion of the filamentous fungus podospora anserina is evolved to be a prion .
it appears to function for the host in hetero - karyon incompatibility , and to be the basis of a striking meiotic drive phenomenon . which is the phenomenon and which is the ' epiphenomenon ' is not yet clear , but in either case , the het - s protein is evolved to be a prion .
only a single prion variant of [ het - s ] has been described , as would be expected for a protein evolved to be a prion .
the infectivity and heritability of yeast prions and the ease of yeast manipulation as exemplified by the work of vishveshwara and liebman make possible detailed studies of different amyloid forms , their generation and interaction with each other and with other cellular components , that would be impossible in the non - infectious amyloid diseases of mammals .
nonetheless , the findings with the prions are applicable to the non - infectious amyloid diseases that pose a burgeoning problem for our aging populations . both the cross - seeding phenomenon , as suggested by the coincident occurrence of amyloids of a peptide , tau , -synuclein and others in the human amyloidoses , and the variant phenomenon , as in the different self - propagating amyloid forms of a , are apparently present in non - infectious amyloidoses .
this work was supported by the intramural program of the national institute of diabetes digestive and kidney diseases . due to journal policy
, we have only sparingly referenced the literature and apologize to those whose work we were unable to specifically mention .
Output:
| prion variants faithfully propagate across species barriers , but if the barrier is too high , new variants ( mutants ) are selected , as shown in a recent bmc biology report
. protein sequence alteration can prevent accurate structural templating at filament ends producing prion variants . |
PubmedSumm6578 | ***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: burkholderia
pseudomallei ( bp ) is the causative agent
for the bacterial septic disease melioidosis .
melioidosis is endemic throughout the tropical southeast pacific region
and is considered a growing global health threat.bp , an environmental saphrophyte
by nature , is intrinsically resistant to multiple antibiotics due
to factors including drug inactivation ( e.g. , -lactamase activity ) ,
a multidrug efflux pump system , and an adaptive physiology that can
alter drug target sites throughout disease progression . as a result
, mortality rates from melioidosis
can approach 50% even with antibiotic treatment . despite increased scrutiny in recent years
, the
mechanisms by which bp can establish and propagate
an infection have remained unclear .
bioinformatics analyses of bp and its genetic relatives burkholderia mallei ( bm ) and burkholderia thailandensis ( bt ) indicate that substantial parts of their genomes
are dedicated to polyketide ( pk)- and non - ribosomal peptide ( nrp)-based
secondary metabolism , which we have hypothesized could be a key component
of burkholderia virulence .
while many of the gene clusters
common to all three species have been studied , clusters that are solely
found within the bp genome have remained uncharacterized ,
and to date , the specific roles that secondary metabolism has in establishing
melioidosis have not been evaluated . herein , we begin the characterization
of the unique secondary metabolome encoded by bp and
show that it is a key factor in melioid virulence .
the importance
of these molecules to bp pathogenicity suggests that
inhibition of their biosynthesis could present a viable avenue for
future therapeutic intervention .
cryptic and/or silent small - molecule
biosynthetic gene clusters
are routinely found within sequenced bacterial genomes .
while biosynthetic gene clusters encoding molecules
required for bacterial pathogenesis must be produced in vivo during an infectious event , many may remain silent in the laboratory
setting due the lack of appropriate environmental stimuli needed to
induce their activation ( figure 1 ) . due to
its nih / cdc select agent status , the manipulation of the bp genome for gaining access to silent biosynthesis has been cumbersome .
as bt
is generally considered to be avirulent in
most mammalian hosts , it has been used as a convenient surrogate model
to study biosynthesis in pseudomallei - group burkholderia species . as much of the bp secondary metabolome has been characterized through bt , neither the identity of the molecules encoded by bp - specific gene clusters nor
recently , the schweizer group developed
a bp adenine auxotroph ( bp82 ) that
has been removed from the select agent list due to its inability to
survive outside the laboratory , providing
a strain with the genetic background with which to study cryptic secondary
metabolism of this important pathogen . examining the influence
of secondary metabolism on bacterial pathogenicity .
( a ) bacterial pathogens typically produce a limited number of metabolites
under laboratory fermentation conditions , ( b ) while having the capacity
to produce multiple metabolites within the context of an infection ,
which can function as virulence factors .
( c ) cryptic / silent gene clusters
can be identified bioinformatically in sequenced pathogen genomes .
through genome engineering ,
individual biosynthetic clusters can be
both activated for accessing the encoded molecules and disrupted for
determining their influence on bacterial pathogenicity .
( d ) virulence
factor biosynthesis can be targeted for the development of new disease - specific
therapeutics .
a comparative genome analysis ( figure 2 and table s1 ) of pseudomallei - group burkholderia
revealed that , although bp , bm ,
and bt share many pk / nrp gene clusters , three gene
clusters are unique to bp ( figure 2 ; clusters 2 , 14 , and 15 ) , and one cluster ( cluster 11 ) is
shared between bp and bm ( but not bt ) . while extensively truncated versions of clusters 14
and 15 appear in the bm genome , cluster 2 is completely
absent .
gene clusters 2 and 15 are predicted to encode for novel lipopeptides ,
cluster 11 is also predicted to encode a novel metabolite but has
a gene organization and content similar to that found in the bt - specific thailandamide biosynthetic cluster , and cluster 14 is predicted to encode a syrbactin - type
structure ( see discussion below ) ( tables s1 and
s2 ) .
we hypothesized that bp - specific cryptic
gene clusters may play an important , and overlooked , role in melioidosis .
to test this hypothesis
, we used homologous recombination to delete
the initial biosynthetic domains ( detailed in table s4 ) within the first either pk or nrp megasynth(et)ase
gene of clusters 2 , 11 , 14 , and 15 , thereby creating four strains
with individually disrupted biosynthetic gene clusters .
this set of
deletions was created in a fully sequenced clinical isolate , b. pseudomallei1026b ( bp1026b ) , under strict bsl3 level biocontainment .
these gene cluster disruption
strains were then tested for pathogenicity using an intranasal
murine infection model ( figure 3 ) .
remarkably ,
disruption of any of the three gene clusters that are uniquely found
in bp ( clusters 2 , 14 , and 15 ) completely abrogated bp1026b murine virulence , even at titers up to 10 times
the bp1026b ld50 inoculum .
disruption
of cluster 11 , which is shared between bp and bm , led to a strain with virulence that was indistinguishable
from the wild - type strain in the murine model .
each of the three nrp / pk
metabolites encoded solely within the bp genome is
therefore individually essential to the pathogenicity of this bacterium .
additionally , the growth rates of these three mutants were identical
to that of wild - type bp1026b ( figure s2 ) , indicating that the disruption of biosynthesis
has no impact on general bacterial fitness . based on their importance
to bp virulence
, we initiated the structural and
functional characterization of the small molecules encoded by this
collection of bp - specific gene clusters . here
the
third cluster ( cluster 2 ) , predicted to encode a five - amino - acid lipopeptide
structure , has so far remained recalcitrant to characterization .
future
studies will focus on activating this remaining silent gene cluster
in the laboratory setting .
comparison of the secondary metabolomes encoded
by b. pseudomallei1026b ( bp ) , b. mallei atcc 23344 ( bm ) , and b. thailandensis e264 ( bt ) .
positioning of individual nrp- and pk - encoding
gene clusters within each genome is displayed .
clusters shared among
the three species are indicated by the connective lines between genomes
( detailed in table s1 ) .
genomes are linearized
and arranged for clarity , with the purple arrowhead designating direction
from the first gene in each chromosome ( i.e. , nucleotide + 1 ) .
clusters
2 , 14 , and 15 ( red ) are unique to bp . cluster 11
( yellow )
genes dedicated to nrp / pk - based secondary
metabolism encompass approximately 6% of the bp genome .
21-day murine intranasal infection challenge
of wild - type bp and the disruption mutants of biosynthetic
clusters 2 ,
11 , 14 , and 15 .
inoculum : 10 ( 10 for cluster 15 ) colony - forming
units . in previous work with bt
, we developed a promoter - replacement
strategy for up - regulating or activating secondary metabolite gene
clusters in burkholderia . in this approach
,
the rhamnose - inducible promoter prhab is inserted directly
upstream of a key operon in a gene cluster of interest , providing
a conditional switch that activates or represses biosynthesis in the
presence or absence of rhamnose , respectively . to investigate cryptic
virulence - associated secondary metabolism in bp ,
we created prhab recombination cassettes targeting the
promoters upstream of the most biosynthetic - rich operons found in
each gene cluster of interest ( i.e. , clusters 2 , 14 , and 15 ) .
these
cassettes were ligated into the allele replacement vector pexkm5 for
use in transformation , recombination , selection , and ultimately promoter
replacement in bp82 . using this approach
, we were able to induce high - level metabolite
production from clusters 14 and 15 ( syr and mpn clusters , respectively ) ,
and then through a combination of bioinformatics , mass spectroscopy ,
and nmr , we characterized the molecules encoded by these two clusters ,
as follows .
on the basis of bioinformatics analysis , we predicted
that the
mpn gene cluster was composed of a unidirectional five - gene locus
( mpna - e ) .
three of these genes , mpnbcd , encode large modular nrp megasynthetases ( nrpss ) that together
are predicted to synthesize a 12-amino - acid peptide ( figure 4a ) .
the mpnb initiation module is predicted to incorporate
an acyl group as a starter unit , suggesting that the mpn cluster would
encode a lipopeptide .
the two additional
genes predicted to reside in the mpn cluster would appear to be responsible
for generating unnatural amino acids for use by the nrpss .
the first , mpna , encodes a diaminobutyrate-2-oxoglutarate
transaminase that is commonly used in 2,4-diaminobutyric
acid ( dab ) biosynthesis , which is supported by the predicted dab substrate
binding specificity of one of the nrps adenylation domains , a7 ( figure 4b ) . the final gene , mpne , is predicted to encode for a syrp - like aspartic / glutamic
acid hydroxylase .
( a ) biosynthetic
gene cluster
encoding the malleipeptins ( genes bp1026b_ii1742 - 1746 , table s2 ) , with prhab promoter
exchange ( red ) . ( b ) predicted nrps domain architecture and adenylation
domain selectivity for mpnbcd .
parentheses indicate amino acids observed
in the nmr - determined final malleipeptin structure that differ
from the bioinformatics prediction .
abbreviations : c , condensation
domain ; cs , starter condensation domain ; cd ,
dual condensation / epimerization domain ; a , adenylation domain ; t ,
peptidyl carrier domain ; te , thioesterase ; dhb , 2,3-dehydrobutyric
acid ; dab , 2,4-diaminobutyric acid ; hglu , 4-hydroxyglutamic
acid .
( c ) hplc traces ( diode array : 254 nm ) of culture broth extracts
from ( a ) bp82 , ( b ) bp82:prhab - mpn ( no rhamnose ) , and ( c ) bp82:prhab - mpn ( rhamnose
induced ) . ( d ) structure of malleipeptins a ( 1 )
and b ( 2 ) with key hmbc / roesy correlations . predicted
tailoring enzyme functionalities ( mpna and mpne ) are highlighted .
the induction of mpn
biosynthesis was achieved through prhab insertion upstream
of mpna to give strain bp82:prhab - mpn . upon induction with rhamnose
,
two major strain - specific metabolites appeared in culture broth extracts
( figure 4c ; 1 and 2 , esi [ m+h]m / z 1384.3
and 1398.2 , respectively ) .
these metabolites were absent in extracts
from both wild - type bp82 and uninduced bp82:prhab - mpn cultures , indicating that , while the mpn cluster
is critical for virulence in vivo , it remains silent
under simple laboratory fermentation conditions .
compounds 1 and 2 were purified by preparative reverse - phase chromatography
from the methanol eluent of hp-20 resin - infused rhamnose - induced bp82:prhab - mpn cultures .
cosy / tocsy analyses
of major compound 2 showed 14
spin systems ( figures s3 and s4 ) . on the
basis of h / c chemical shift data and hmqc / hmbc
correlations , 12 of these are predicted to be amino acids .
c hmbc correlations between amide protons and
adjacent carbonyl groups , with supporting h h roesy correlations ,
defined the order of the 12 amino acids
( figures 4d and s3 ) .
intramolecular cyclization through the threonine side chain ( position
9 ) to form a 13-member macrolactone is supported by an hmbc correlation
between the -carbon methine proton ( h 5.37 )
of threonine and the carbonyl carbon of the c - terminal isoleucine
residue ( c-1 169.2 ) .
the final two cosy spin
systems are predicted to be part of an acyl substituent .
an hmbc correlation
between the carbonyl ( c-1 165.8 ) that is
connected by hmbc correlations to the olefin - containing spin system
and the serine amide proton ( h 8.24 ) confirms attachment
of acyl group to the n - terminus .
ultimately ,
the exact length of the acyl substituent ( 2-(e)-decenoic )
was determined on the basis of the molecular formula predicted by
hrms - tof ( m / z [ m+h ] calcd
for c62h105n14o22 , 1397.7511 ;
found , 1397.7528 ) .
minor product 1 differs from 2 by ch2 , based on the ms - predicted formula ( hrms - tof m / z [ m+h ] calcd for c61h103n14o22 , 1383.7372 ; found , 1383.7365 ) .
the same general nmr / ms arguments used to define the structure of 2 were used to establish the structure of 1 ,
with the exception that h , c , and both the
cosy and tocsy spectra indicate the c - terminal amino acid is a valine
instead of an isoleucine .
we have assigned these new lipopeptides
the names malleipeptin a ( 1 ) and malleipeptin
b ( 2 ) .
malleipeptins a and b are 12-amino - acid
lipopeptides with
a novel peptide sequence and a rarely seen 13-membered terminal lactone .
the primary malleipeptin amino acid sequence is in very good
agreement with the bioinformatics prediction from the primary mpnbcd
nrps ( figures 4b ) .
one exception is that 2,3-dehydro-2-aminobutanoic
acid ( dhb ) , a dehydrated threonine residue , is incorporated at the
position predicted to contain a threonine .
the biosynthesis of the
hydroxyglutamic acid ( hglu ) moiety seen at position 10 is supported
by the presence mpne , which is a predicted syrp - like aspartic / glutamic
acid hydroxylase.h and cosy
spectra with supporting h
c hmqc correlations
indicate that the oxidation occurs at the c-4 methine ( c-4 66.3 ) , instead of the more common c-3 position ( figure s5 ) .
the presence of dual condensation / epimerization
domains in five of the nrps modules indicates
the incorporation of d - amino acids directly upstream of these
domains at positions-1 , 3 , 5 , 7 , and 10
( figure 4b ) , as is drawn in figure 4d .
the tandem thioesterases ( te1te2 ) found at the n - terminus of mpnd are commonly seen in large
lipopeptide biosynthetic clusters and are predicted to encode
for both intramolecular cyclization and proofreading to ensure the
fidelity of the biosynthetic assembly line .
the malleipeptins are the first lipopeptides characterized
from pseudomallei - group burkholderia and are distinct from lipopeptides
produced by unrelated burkholderia species ( e.g. , burkholdine , occifungin ) .
the nrpss responsible for the assembly of the malleipeptins
do not align well to any deposited nrps sequences outside of those
found in other sequenced bp strains , indicating that
the mpn cluster encodes for a novel structural family of lipopeptides
that is so far solely associated with bp virulence .
the syr cluster is comprised of nine genes ( syra i ) that are unidirectionally oriented ( figure 5a ) .
bioinformatics analysis predicted this gene cluster was likely
to encode a syrbactin - type proteasome inhibitor , as indicated by homologues
of genes known to encode the hybrid pk / nrp syrbactin warhead
that binds to the 20s proteasome active site ( syregfhi ) .
in addition , this cluster is predicted
to contain a set of genes ( syrabcd ) putatively responsible
for synthesis and transfer of an acyl group ( figure
s23 ) . while syrbactins have been characterized from bacteria
that are pathogenic to plant and insect hosts , this is the first syrbactin - type
cluster identified within a mammalian pathogen . to study this cluster
,
we exchanged the promoter upstream of syra with prhab , yielding strain bp82:prhab - syr .
hplc analysis of ethyl acetate extracts from rhamnose - infused
cultures of bp82 and bp82:prhab - syr showed a dramatic increase in two metabolites in the
induced bp82:prhab - syr cultures ( figure 5b ; 3 and 4 ) .
these metabolites
are absent in extracts from uninduced bp82:prhab - syr cultures , confirming the activation / repression phenotype
provided by the prhab promoter and coupling compound 3 and 4 production to syr gene cluster induction .
compounds 3 and 4 were purified from ethyl
acetate extracts using a modified kupchan scheme followed by silica
gel flash chromatography and preparative reverse - phase hplc .
ms and
nmr data indicate that compound 3 is identical to the
syrbactin glidobactin c ( hrms - tof m / z [ m+na ] calcd for c29h48n4o6na , 571.3514 ; found , 571.3483 ) , which is characterized
by the acylation of the pk / nrp warhead with a 2(e),4(e)-diene derivative of myristic acid ( figure 5c ) .
the hrms - predicted molecular formula for 4 differs from that of 3 by one oxygen atom ( hrms - tof m / z [ m + na ] calcd for c29h48n4o5na , 555.3522 ; found ,
555.3520 ) .
h and c chemical shift data as
well as cosy , hmqc , and hmbc correlation data indicate that compound 4 contains lysine , instead of 4-hydroxyllysine , within the
warhead substructure . to our knowledge , this syrbactin variant , which
we assign the name deoxyglidobactin c ( 4 ) , has
not been reported previously .
( a ) biosynthetic gene cluster
encoding for the syrbactins ( genes bp1026b_ii1345 - 1353 ; table s2 ) with prhab promoter
exchange ( red ) .
( b ) hplc traces ( diode array : 254 nm ) of culture broth
extracts from ( a ) bp82 , ( b ) bp82:prhab - syr ( no rhamnose ) ,
and ( c ) bp82:prhab - syr
( rhamnose induced ) .
( c ) structures of glidobactin c ( 3 ) and deoxyglidobactin c ( 4 ) .
while syrbactins are known proteasome inhibitors , the biological
activity of the malleipeptins was unknown . at the highest levels
tested , the malleipeptins showed no general toxicity against
bacterial ( 100 g / disk ) or human cells lines ( 100 g ml ) .
a common function among non - cytotoxic lipopeptides
is surfactant activity . in bacteria ,
biosurfactant production is thought
to reduce the surface tension at water / hydrophobic interfaces , thereby
helping to increase growth on surfaces ; in pathogens , they have been
shown to aid in bacterial invasion mechanisms . using a toluene emulsion assay , we tested the emulsive potential
of bp82 and bp82:prhab - mpn cultures both in the presence and in the absence of rhamnose .
only the induced bp82:prhab - mpn supernatant
formed any emulsion when mixed 1:1 with organic solvent , indicating
that a potent surfactant property is , in fact , associated with malleipeptin
production ( figure 6a ) .
as biosurfactants have
also been shown to possess a role in modulating biofilms , we examined the effect of malleipeptin on bp82 biofilm production . at concentrations as low as 1 m , malleipeptin
disrupted bp82 biofilm formation ( figures 6b and s32 ) . on the basis
of these observations , we believe malleipeptins are biosurfactants
that are required at some stage during bp infections .
equal parts toluene and supernatant were combined , vortexed ,
and then let stand for 2 h. ( a ) bp82 , no rhamnose ; ( b ) bp82 , plus rhamnose ;
( c ) bp82:prhab - mpn , no
rhamnose ; ( d ) bp82:prhab - mpn , plus rhamnose ; ( e ) lb medium ( blank ) .
( b )
microtiter plate assay showing increasing disruption of bp82 top biofilm with increasing concentrations of 2 ( 200
l cultures , 30 c , 48 h ; 20 magnification ) .
comparative genome analyses
led us to three small - molecule biosynthetic
gene clusters that are required for bp pathogenicity .
in a previous study involving bt , we showed that
the lipophilic siderophore malleilactone , which is encoded by
a gene cluster that is shared among bp , bm , and bt ( figure 2 , cluster
8) , strongly influences the virulence of bt in non - mammalian
models .
taken together , these works illustrate
that small molecules play critical , yet largely overlooked , roles
in burkholderia pathogenesis ( figure 7 ) .
additionally ,
the identification and characterization of small molecules encoded
by cryptic gene clusters associated with virulence , especially when
studying highly controlled select agent pathogens like bp , provide a means to potentially more safely dissect the detailed
mechanisms of melioidosis .
small - molecule
biosynthesis is predicted to influence bp virulence
through diverse mechanisms : ( a ) bacterial invasion , ( b ) systemic toxicity ,
and ( c ) acquisition of nutrients .
the inhibition of these overlooked
components of bp virulence should provide novel avenues
for the development of bp - specific anti - infective
agents . as the pathogenicity of bp
is known to involve
intracellular replication following invasion of both epithelial and
macrophage cells , potential roles for secondary metabolites within bp pathogenicity can be proposed .
biosurfactants have been
shown to disrupt epithelial integrity , facilitate paracellular infiltration
by bacterial pathogens , and support intercellular communication among
bacteria by improving the solubility of lipophilic quorum sensing
molecules .
the malleipeptins may play
similar roles in bp pathogenicity , potentially aiding
in bacterial infiltration and disease progression .
proteasome inhibition
is known to directly activate programmed cell death through induction
of apoptosis and autophagy across multiple cell lines , including macrophages . in the context of bp infections
, autophagy has
been shown to be critical for diverting host nutrients to the pathogen .
proteasome inhibition by the glidobactins
could therefore provide the mechanistic explanation for both promoting
intracellular replication or , in the case of macrophages , immunosuppression ,
which has long been suspected within bp pathogenicity . in light of the importance of these small molecules
to bp pathogenesis , the inhibition of their biosyntheses
could prove to be a productive avenue for the development of next - generation
therapeutics for combating melioidosis .
deletion of biosynthetic clusters was performed via a two - stage
pcr strategy , wherein a key region of genomic dna was excised by homologous
recombination of dna designed from genetic regions both upstream and
downstream of the targeted excision region .
upstream and downstream regions ( 1 kb in length ) were amplified
from bp1026b genomic dna in a volume of 50 l
with 50 pmol of primer pair ( primers 2f/2r and primers 3f/3r ; listed
in table s3 ) , 1x failsafe premix e ( epicentre ) ,
and 5 u phusion polymerase ( neb ) .
pcr cycling conditions were as follows :
98 c for 30 s , 30 cycles of 98 c for 30 s ; annealing at
62.5 c for 30 s ; 60 s extension at 72 c ; 72 c , 1
min .
primers were designed to ligate into the sacb - based vector pexkm5 as a smai / xhoi cassette using the in - fusion cloning kit
( clontech ) .
each fragment was gel purified with qiagen pcr purification
kit , and the fragments were ligated together into 2 kb fragments
by a second round of pcr with the above protocol using primers 2f
and 3r and 1 ng of each product from the initial pcr reaction .
the extension time
was increased to 2 min , with final 72 c incubation
at 2 min .
recombinant
derivatives of pexkm5 were electroporated into e. coli s17 - 1 and conjugated with b. pseudomallei for 8
h , as described elsewhere.bp1026b transconjugants were selected with kanamycin ( 1000 g
ml ) , and polymyxin b ( 25 g ml ) was used to counterselect e. coli s17 - 1 .
optimal conditions for resolution of the sacb constructs were found to be lb agar lacking nacl and containing
10% sucrose , with incubation at 25 c for 34 days .
colony pcr was performed by resuspending an isolated
sucrose resistant colony in 50 l of water and using 5 l
of the suspension in a pcr reaction .
pcr amplifications were performed
in a final reaction volume of 50 l containing 1x failsafe premix
d ( epicentre ) , 1.25 u of failsafe pcr enzyme mix ( epicentre ) , and
1 m pcr primers .
pcr cycling conditions were as follows : 97
c for 5 min , 30 cycles of a three - temperature cycling protocol
( 97 c for 30 s , 55 c for 30 s , and 72 c for 1 min ) ;
72 c , 10 min .
confirmation primers were designed to show a 500
bp region from the fusion of the upstream and downstream regions of
the excised target locus , as verified by agarose gel ( figure s1 ) .
b. pseudomallei animal work was
conducted under animal biosafety level 3 ( absl3 )
conditions in accordance with institutional animal care and use committee
regulations at the u.s .
six- to eight - week - old female balb / c mice ( national cancer
institute , frederick , md ) were anesthetized with a 0.10.2
ml intraperitoneal injection of ketamine hcl , acepromazine ,
and xylazine ( k - a - x ) .
the k - a - x solution was prepared by combining
5 ml of ketamine hcl ( 100 g ml ) and 0.5
ml of acepromazine ( 10 g ml ) with 2.75
ml of xylazine ( 20 g ml ) and mixing 1 ml
of the resulting solution with 9 ml of saline .
b. pseudomallei strains were grown overnight in lennox lb broth and then serially
diluted in phosphate - buffered saline , and 1010 colony - forming units were used to inoculate groups of 10
mice by intranasal instillation .
briefly , 50 l of the
bacterial inoculum was gradually released into the nostrils of anaesthetized
mice using a gilson pipetman p200 .
the infected animals were monitored
daily for a period of 21 days , at which time the survivors were euthanized
with co2 , and the 50% lethal dose ( ld50 ) was
calculated .
avirulent bp strain , bp82 , was
derived directly from bp1026b through deletion of
the purm gene responsible for de novo adenine synthesis , and all primers
were based on the bp1026b genome sequence .
all media
formulated for adenine auxotroph bp82 strain culturing
were supplemented with adenine ( 80 g ml ) and thymidine ( 5 g ml ) . for dual activation / suppression
of individual biosynthetic gene clusters in bp82 ,
we previously designed a strategy for replacing native promoter regions
upstream of an individual biosynthetic cluster with an inducible promoter
imposing tight repression of transcription in burkholderia ( i.e. ,
promoter exchange ) , detailed by biggins et al .
promoter exchange cassettes containing the rhamnose - inducible promoter
prhab and the dhfr trimethoprim resistance
gene ( from pscrhab2 vector ) , flanked
on each side by 1 kb of sequence homologous to the specific
recombination sites in the burkholderia genome , were constructed by
successive rounds of pcr / restriction digest / ligation .
each 4.8
kb promoter exchange cassette was pcr amplified from its puc - rha parent
clone with primer pair 2f/3r , gel purified , treated to afford blunt - ended
phosphorylation ( end - it dna repair kit ; epicenter ) , and ligated into
vector pexkm5 at the cip - treated smai site within
the multicloning region .
each pexkm5-cloned variant was transported
into e. coli s17 - 1 and conjugated with bp82 , as described.bp82/e .
coli co - cultures were resuspended in 250 l
of lb medium and selected over 23 days on selection media
lb agar / kanamycin ( 1000 g ml)/trimethoprim
( 100 g ml ) .
merodiploid bp82 colonies were
picked and restreaked on a fresh selection plate for 48 h. a single
colony was then grown in 1 ml of yt medium overnight and plated on sacb - curing media yt agar / trimethoprim
( 100 g ml)/x - gluc ( 50 g ml)/15% sucrose for 23 days at 30 c .
excision of the
plasmid backbone was verified by white colony phenotype and the inability
to survive against kanamycin ( 1000 g ml ) selection .
proper recombinant transformants were verified for proper
insertion / recombination by pcr using primer pair 4f/5r for proper
4.8 kb fragment containing prhab and flanking hybridization
domains .
seamless insertion of promoter prhab was verified
by amplifying the region within the prhab promoter and
downstream of the insertion site with primer pairs 5f/5r , gel purifying
each 1 kb fragment , and sanger sequencing to verify that no
mutations occurred during the cloning process .
strain bp82:prhab - mpn was grown overnight
to confluence in lb / trimethoprim ( 100 g ml ) , and then 500 l was inoculated into 50 ml of lb / trimethoprim
( 100 g ml)/0.2% l - rhamnose with
1.5 g of hp-20 resin added and incubated at 30 c , 200 rpm , 72
h. an identical control culture lacked the addition of l - rhamnose
to the culture medium .
after 72 h , resin was filtered from the broths ,
washed twice in equal amounts of deionized water , and dried overnight
in a laboratory fume hood .
dried resins were resuspended in 10 ml
of methanol , sonicated , decanted , dried in vacuo ,
and monitored by reverse - phase hplc - ms ( linear gradient from 10:90
ch3cn / h2o with 0.1% formic acid to 100% ch3cn with 0.1% formic acid over 50 min ; 0.7 ml min ; waters xbridge c18 , 5 m , 4.6 150 mm ) . rhamnose - induced
culture ( illustrated in figure 4c ) displayed
two major peaks ( retention times : 22.6 min , 1 ; 23.4 min , 2 ) that are not present in the control cultures .
strain bp82:prhab - syr was grown overnight to confluence
in lb / trimethoprim ( 100 g ml ) , and then
500 l was inoculated into 50 ml of lb / trimethoprim ( 100 g
ml)/0.2% l - rhamnose and incubated at
30 c , 200 rpm , 72 h. an identical control culture lacked the
addition of l - rhamnose to the culture medium . after 72 h ,
20 ml of culture broth was extracted with an equal amount of ethyl
acetate , dried in vacuo , and monitored by reverse - phase
hplc - ms ( linear gradient from 10:90 ch3cn / h2o with 0.2% trifluoroacetic acid to 100% ch3cn with 0.2%
trifluoroacetic acid over 50 min ; 0.7 ml min ;
waters xbridge c18 , 5 m , 4.6 150 mm ) . rhamnose - induced
culture ( illustrated in figure 5c ) displayed
two major peaks ( retention times : 31.6 min , 3 ; 34.0 min , 4 ) that are repressed in non - induced cultures .
the emulsive potential of malleipeptin
producing extracts of bp82:prhab - mpn cultures
was tested against wild - type bp82 , both with ( induction )
and without 0.2% l - rhamnose added to media , using toluene
as an organic solvent .
confluent cultures
of each strain were grown overnight from a freshly restreaked colony
in lb medium .
aliquots of 50 l of lb media , both with and without
added 0.2% l - rhamnose , were inoculated with 500 l
of each strain and incubated ( 48 h , 200 rpm ; 30 c ) .
one milliliter
of each culture was pelleted ( 60 s ; 15000 g ) , from
which 500 l was mixed with an equal volume of toluene in a
glass vial , vortexed vigorously , and rested for 2 h. lb media alone
was used as a blank control .
a confluent
culture of bp82 was grown overnight from a freshly
restreaked colony
in lb medium , inoculated into 50 ml
lb medium , and grown to od600 0.5 ( 200 rpm ; 37 c ) , after which the culture was
diluted 1:100 and seeded in 96-well plates ( 200 l / well ) .
the
concentration of purified malleipeptin b ranged from 100 g
ml ( 70 m ) to 0.34 g ml ( 0.24 m ) ( 2.25-fold dilution increments ) .
blank controls
( methanol solvent vector ) were co - incubated in adjacent wells .
cultures were incubated ( 48 h ; 80 rpm ; 30
c ) , and top biofilm formations were visualized through a dissecting
stereoscope .
disruption in biofilm is evident in cultures with ligand
concentration above 1 m malleipeptin b , wherein
biofilms become increasingly porous and fragmented .
still pictures
were taken with a leica m60 stereoscope affixed with an ic80hd camera
( 20 magnification ) .
Output:
| increasing evidence has shown that
small - molecule chemistry in
microbes ( i.e. , secondary metabolism ) can modulate the microbe
host
response in infection and pathogenicity .
the bacterial disease melioidosis
is conferred by the highly virulent , antibiotic - resistant pathogen burkholderia pseudomallei ( bp ) . whereas
some macromolecular structures have been shown to influence bp virulence ( e.g. , secretion systems , cellular capsule ,
pili ) , the role of the large cryptic secondary metabolome encoded
within its genome has been largely unexplored for its importance to
virulence .
herein we demonstrate that bp - encoded
small - molecule biosynthesis is indispensible for in vivo bp pathogenicity .
promoter exchange experiments were used to induce
high - level molecule production from two gene clusters ( mpn and syr )
found to be essential for in vivo virulence .
nmr
structural characterization of these metabolites identified a new
class of lipopeptide biosurfactants / biofilm modulators ( the
malleipeptins ) and syrbactin - type proteasome inhibitors , both
of which represent overlooked small - molecule virulence factors for bp .
disruption of burkholderia virulence by inhibiting the
biosynthesis of these small - molecule biosynthetic pathways may prove
to be an effective strategy for developing novel melioidosis - specific
therapeutics . |
PubmedSumm6579 | ***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:
| we investigated mammary gland differentiation and cell proliferation in rats after acute exposure to xenoestrogens .
pubertal female sprague - dawley rats ( six / group ) were treated for 1 week with diethylstilbestrol ( des ) , genistein , o , p'-ddt , aroclor 1221 , aroclor 1254 , 2,3,7,8-tetrachlorodibenzo - p - dioxin ( tcdd ) , or the vehicle , sesame oil . animals were killed 18 hr after the last treatment .
analysis of mammary whole - mounts revealed that exposure to des , genistein , and o , p'-ddt resulted in enhanced gland differentiation and increased epithelial cell proliferation as measured by proliferating cell nuclear antigen immunohistochemistry , tcdd treatment inhibited cell proliferation and gland development .
aroclor 1221 and aroclor 1254 treatments had slight but not statistically significant effects on cell proliferation and mammary gland development .
we conclude that des , genistein , and o , p'-ddt given to pubertal rats act as morphogens ; i.e. , they increase cell proliferation , which promotes maturation of the undifferentiated terminal end buds to more differentiated lobular terminal ductal structures.imagesfigure 1 .
afigure 1 .
bfigure 2.figure 3 .
afigure 3 .
bfigure 3 .
cfigure 3 .
dfigure 4.figure 5.figure 6 . |
PubmedSumm6580 | ***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: infantile tremor syndrome ( its ) is characterized by anemia , skin pigmentation , tremors , physical , and mental regression without a defined etiopathogenesis and low incidence .
we have studied 9 patients over 1 year for the changing clinical and laboratory variables of patients with its .
neuroregression and anemia were presented in all followed by tremors in 5 and hypotonia in 2 .
infantile tremor syndrome ( its ) is a syndrome characterized by anemia , skin pigmentation , tremors , physical , and mental regression .
it has been reported in children between 5 months and 3 years of age with a male predominance .
the purpose of this case series was to determine factors responsible for its continuing prevalence despite better knowledge and weaning practices .
we have studied 9 patients presenting to us with typical features of its and pre - its in a tertiary care hospital of hilly terrain [ table 1 ] . a detailed history and examination
investigations included complete hemogram , peripheral smear to type the anemia and malaria parasite , serum electrolytes , renal and liver function tests along with sepsis screen , and urine routine examination .
blood and urine cultures , serum b12 levels , chest x - ray , and tuberculosis screen were done when indicated . written informed consent was taken from all .
total 9 patients , 3 males and 6 females presented over the period of 1 year .
the mean age of presentation was 13.5 months , ranging from 7 months to 18 months .
all ( 100% ) patients admitted with the complaint of lethargy and weakness with a mean duration of 21 days .
neuroregression was present in all ( 100% ) with a mean delay of 7 months ranging from 4 to 11 months in all spheres of development .
tremors were present in 5 ( 55% ) and hypotonia in 2 ( 22% ) reflecting neurological changes .
seven ( 78% ) were exclusively breastfed and 2 ( 22% ) improperly weaned with diluted milk .
protein energy malnutrition was present in 5 ( 55% ) out of which 2 ( 40% ) had grade i and 3 had grade ii ( 60% ) protein energy malnutrition as per iap classification .
ofc records of all patients were within normal range for their age [ table 2 ] .
all had severe pallor ( 100% ) with knuckle hyperpigmentation and sparse hair in most .
hepatomegaly was present in 4 ( 44% ) , splenomegaly in 2 ( 22% ) , and pneumonia in 1 ( 11% ) .
peripheral blood film examination revealed the macrocytic picture in 4 ( 44% ) , dimorphic in 4 ( 44% ) , and microcytic in 1 ( 11% ) .
chest x - rays had infiltrated in 3 ( 33% ) but workup for tubercular screening was negative .
urine cultures were positive in 2 ( 22% ) with escherichia coli and pseudumonas in 1 each .
serum b12 levels were low in 4 out of 5 patients but could not be performed in all due to financial constraints .
the mean duration of hospital stay was 9 days ranging from 4 to 16 days .
total 6 ( 66% ) with positive sepsis screen or cultures received antibiotics for the average duration of 9 days .
improved after treatment with supplements such as vitamins a , d , k , b - complex , zinc , calcium , and magnesium along with dietary management .
on monthly follow - up , those with pre - its had better catch up in growth and development in all spheres .
infantile and pre - its is a well - known clinical entity reported primarily from the developing nations . despite its decreasing incidence , the finding of additional clinical features made us present this series .
associated nutritional deficiencies such as protein , vitamin a , d , c , and b - complex may be present .
our series also found that all children with this syndrome had anemia , lethargy , and neuroregression and presented throughout the year with no seasonal clustering as previously stated .
furthermore , the type of anemia in this disease is not specific . on the other hand , it reflects the pattern of prevalence of the hematinic deficiencies in the region .
however , unlike previous reports , there were more female patients , which may be due to bias in nutritional status .
the study adds the need for rational antibiotic use in patients of its , unlike many previous reports where all patients have been administered antibiotics .
the disease process may be superadded by urinary infections probably due to lower immunity state as a result of malnutrition , the leading cause of acquired immunodeficiency .
it is also a reflection of changing epidemiology with no seasonal variation , showing the role of non - viral etiologies although previous studies show a seasonal pattern of disease .
it highlights the need for better education for weaning practices and need for better community support .
Output:
| background : infantile tremor syndrome ( its ) is characterized by anemia , skin pigmentation , tremors , physical , and mental regression without a defined etiopathogenesis and low incidence.materials and methods : we have studied 9 patients over 1 year for the changing clinical and laboratory variables of patients with its .
neuroregression and anemia were presented in all followed by tremors in 5 and hypotonia in 2.result:sepsis screen was positive in 6 and urine cultures in 2 .
antibiotics were required in 6 .
its with changing parameters still significantly contributes to healthcare burden.conclusion:it is important to screen for urinary infection and septicemia to avoid antibiotic abuse . |
PubmedSumm6581 | ***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 manifold unusual semiologies of epilepsy , pure epileptic chest pain has not received attention to date .
pain occurs in a small minority of patients with epilepsy but is often accompanied by other motor , sensory or behavioural features which denote their ictal origin .
the clinical history and video - eeg features of a young boy , who presented with episodic chest pain , is described to illustrate this atypical presentation .
a 14-year - old boy preparing for his final exams was brought by his mother for evaluation of episodic left - sided chest pain of 2 weeks duration . the pain which lasted a few seconds to half a minute
was described as sharp , excruciating and localized to the lower chest on the left side and involved an area of only two finger breadths . the frequency varied from 1 to 8 episodes per day with variable severity but consistent location .
there were no accompanying clinical features like breathlessness , diaphoresis , palpitation , fear , abnormal behavior or movements .
there was no antecedent illness or trauma ; no history of febrile seizures , encephalitis or perinatal insult .
he was evaluated by a pulmonologist and cardiologist who performed relevant investigations including a chest ct scan , electrocardiogram , and echocardiogram which returned normal findings .
he was referred to a psychiatrist but the family preferred to get an opinion at our neurology center .
an interictal eeg was initially performed which showed spike - and - wave discharges in the awake state distributed frontocentrally over the left hemisphere ( fig .
1 ) . this prompted us to obtain a long term video - eeg recording . during the 24 h of study
, five events were recorded of which only one was associated with a clear - cut ictal pattern .
the clinical semiology was dominated by severe localized chest pain in the right lower chest ( as opposed to the typical left - sided location for chest pain ) .
however some paucity of movements were observed on the right side especially the right upper limb .
the initial part of the ictal recording was obscured by artifact while a nicely evolving 4.04.5 hz rhythm was noted in the parasagittal region a few seconds after clinical onset . a 910 hz faster rhythm was also observed in the left mid and posterior temporal regions which did not show evolution ( fig .
2 ) . a 1.5 tesla mri of the brain did not reveal any focal pathology .
the electroclinical data offered definitive proof for the ictal origin of the phenomenology from the left hemisphere .
this drug was chosen as first line , because the family wanted seizure freedom in a short time as his exams were due in two days .
he has had no seizures , behavioural or cognitive abnormalities during the last four months of follow - up .
epileptic pain as a somatosensory manifestation of seizures is not uncommon but as a solitary presentation of epilepsy is extremely rare and diagnostically challenging .
pazarci et al . who searched for this elusive symptom in their data base of 4736 patients identified only 9 patients .
their experiences consisted of nuchal pain , headache , abdominal pain and pain in the extremities ( peripheral pain ) .
the ictal eeg more often showed hemispheric or diffuse abnormalities than focal well - defined ictal activity . in our patient
the lateralization was clearly evident compared to localization although the parasagittal region showed the most unequivocal changes .
all the patients in their study who had lateralized peripheral pain had an abnormal mri while our report describes mr - negative algic seizures .
structural abnormalities were a universal feature of patients with peripheral pain in a previous series of 8 patients with ictal pain .
one of the patients had only biparietal atrophy evident on mri whose spect study corroborated the finding .
the electrographic abnormalities were either restricted to the parietal area or hemisphere on the surface eeg .
intracranial recordings in three patients showed seizure onset from inferior parietal lobule / parietal operculum or medial parietal lobe . in another analysis of retrospective data of more than five thousand patients , the authors found pain associated with seizures associated with epilepsy in 10 patients of whom 8 had peripheral location of pain .
three of their patients had a normal mri while two had a central location of ictal onset which is comparable to our observation .
however none of these patients in any of the above mentioned series had pain as the sole manifestation of epilepsy thus making our observation a novel one .
the major studies which address epileptic pain due to seizures associated with epilepsy are summarised in table 1
, , , .
none of the patients in these reports had isolated chest pain as an ictal manifestation which makes this case unique and challenging .
the patient had several events during the long term recording without any eeg abnormalities until he had an event with definite ictal abnormalities .
this emphasizes the need for a high index of suspicion to discover the ictal origin of unexplained pain .
pain has a localization more or less similar to somatosensory aura . when the seat of origin is the primary sensory area , a
secondary sensory area ( ssa-2 ) involvement produces vague or complex sensations which are more diffuse in distribution .
posterior insular involvement can also produce sensory phenomena like warmth or dysesthesias which encompasses a widespread cutaneous distribution .
supplementary somatosensory - motor area and cingulate cortex are the other anatomical sites whose involvement can result in sensory manifestations .
the ictal origin of pain in the present report was established by the presence of electrographic abnormalities and response to antiseizure drugs .
this bears resemblance to ictal epileptic headache observed especially in the pediatric age group diagnosis of painful seizures which is based on similar grounds .
the location and nature of ictal pain is variable as evidenced in this report of pure left - sided chest pain .
a dedicated evaluation by video - eeg telemetry can be invaluable in establishing the diagnosis in such cases .
Output:
| purposeto investigate the probable ictal origin of unexplained episodic chest pain and if possible to lateralize and localize the epileptic focus.methodsa 14 year old boy presented with episodic short lasting localized chest pain .
his cardiac and other systemic work - up were normal .
mri brain did not reveal any structural pathology .
video telemetry was done for characterization of the paroxysms.resultsinterictal record showed left fronto - central epileptiform discharges .
a left hemispheric , predominantly centroparietal ictal rhythm was identified .
the possible localizations of this unusual semiology are somatosensory areas i and ii , supplementary sensorimotor area , posterior insula and cingulate cortex .
patient responded remarkably to antiseizure drugs.conclusionpain is a rare manifestation of epilepsy observed in less than 1% of patients .
when present , it is usually accompanied by other focal features .
this rare occurrence of epileptic seizures masquerading as angina is a novel observation . |
PubmedSumm6582 | ***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: marginal gingival recession is not an uncommon feature in almost all populations regardless of oral hygiene . covering exposed root surfaces
are indicated mainly in subjects with esthetic demands , root sensitivity , and cervical caries .
all free - graft procedures require a donor site and result in an additional wound site and discomfort for the patient while pedicle flaps without tissue grafts do not require harvesting the graft from a donor site and have been used for root coverage successfully .
one of the predictable techniques for recession coverage is the coronally positioned flap ( cpf ) .
it is a relatively easy procedure for the clinician and patient , with satisfactory esthetic results without the need for a second surgical site . despite the positive results reported by all root coverage procedures , surgical techniques using particular subepithelialized connective tissue graft and matrix graft should be considered as the first and second choice procedures , respectively , when complete root coverage is the desired outcome .
the reported range of root coverage with cpf is 70 - 99% with a mean of 83% .
the additional use of demineralized agents of varying ph as an adjunct to root coverage procedures has been recommended in order to remove the smear layer and bacterial toxins , to expose collagen fibers on the dentin surface , facilitate cell migration and retard epithelial downgrowth .
several controlled clinical trials comparing the effects of different surgical techniques with and without use of citric acid did not show any beneficial clinical effect from the use of citric acid .
some studies comparing the effects of etching agents operating at neutral ph ( ph = 7 ) such as ethylene diamine tetraacetic acid ( edta ) and agents operating at low ph such as citric acid ( ph = 1 ) demonstrated improved healing following etching with edta in comparison to controls with no etching or citric acid etching .
edta root treatment may facilitate the formation and adherence of the blood clot to the root surface , whilst maintaining the vitality of the surrounding periodontium .
in contrast , low ph agents may dissolve and alter the collagenous fibrillar surface resulting in a granulated rather than fibrous dentin surface .
the aim of the present study was to compare the clinical efficacy of cpf procedure with and without the additional use of root surface demineralization agents of varying ph ( edta , 24% , ph = 7and citric acid ph = 1 ) in treatment of recession type defects .
this randomized controlled trial was performed on 27 systemically healthy and non smoking patients who were referred to the department of periodontology , school of dentistry , tehran azad university , for treatment of buccal recession type defects .
patients of any age in both gender were eligible if they had at least one miller class i buccal gingival recession 2 mm , single - rooted teeth , at least 2-mm keratinized tissues , a good occlusal relationship , and no caries or cervical restorations .
exclusion criteria included sites with probing depths ( pds ) > 3 mm , poor oral hygiene ( oleary plaque index 20% ) , systemic illness , compromised immune systems , pregnancy , taking any drug known to cause gingival enlargement .
also , patients allergic or sensitive to any medication or those who had contraindications for periodontal surgery were excluded from the study .
the present study was assessed and approved by the ethical committee of the islamic azad university of tehran , and written informed consent was obtained from all patients .
following selection , all patients received plaque control instruction and professional tooth cleansing on all tooth surfaces . in each patient , tooth or teeth with areas of gingival recession
was randomly assigned into three groups ( group i and ii ) of test and control , using random - maker software random allocation .
two test groups received surgical treatment modalities consisted of recession coverage by cpf technique with additional application of demineralization agents either edta gel or citric acid on the denuded root surfaces .
the control ( group iii ) teeth were treated similarly but without additional application of any root conditioner .
after local anesthesia , an intrasulcular incision was made with a-15c surgical blade on the buccal aspect of the involved tooth .
the adjacent papillae were only partially involved to preserve soft tissue and to leave the buccal gingival margin of the adjacent teeth intact .
two oblique releasing incisions were made from the mesial and distal extremities of the intrasulcular buccal incision beyond the mucogingival junction .
the interdental papillae were preserved as much as possible ( facial portion was de - epithelialized to create a connective tissue bed ) .
the full - thickness trapezoidal flap exposed the marginal bone of the dehiscence on the root surface 3 mm [ figures 1a - c ] .
( a ) right maxillary cuspid treated with the edta gel ( preoperative view ) ; ( b ) oblique incisions ; ( c ) raising a trapezoidal full - thickness flap ; ( d ) edta application to the exposed root ; ( e ) the flap sutured in the new coronal position ; ( f ) healing 6 months post - surgery the exposed root surface was planned using hand instruments .
a horizontal releasing incision was made in the periosteum at the base of the flap to allow for a tension free coronal flap .
the root surface in the edta group was conditioned with edta gel ( 24% ph = 7 ) with rubbing technique using a cotton pellet for 3 min .
the cotton pellet was changed approximately every 30 s followed by copious irrigation with sterile saline [ figure 1d ] . in the acid group ,
the roots were treated with citric acid using a cotton pellet soaked in aqueous solution of citric acid ( ph = 1 supersaturated ) for 20 s and followed by copious irrigation with sterile saline [ figure 2a ] .
( a ) left mandibular lateral incisor treated with the citric acid ( preoperative view ) ; ( b ) the 6-month result the coronally advanced flap was secured at the level of the cementoenamel junction ( cej ) by suturing to the de - epithelialized papillae using 4 - 0 silk sutures and a single - sling suturing technique .
interrupted sutures were then used for releasing incisions [ figure 1e ] . the same surgical procedure was performed for recessions in controls with the exception of not applying any root conditioner on the root surfaces [ figure 3a ] .
( a ) right maxillary cuspid as control case ( preoperative view ) ; ( b ) the 6-month result patients were instructed to discontinue tooth brushing for 1 week and flossing for the first 4 weeks in the treated areas to avoid trauma around the surgical site , to rinse twice daily with 0.2% chlorhexidine digluconate solution ( for 45 s ) , and to use modified stillman brush technique .
all patients were seen at 1 , 2 , 3 , and 6 months post - surgery to monitor their oral hygiene condition . at these visits , all measurements and clinical photographs
were obtained and oral hygiene instructions were reviewed by a single examiner who was different from the surgeon and , if needed , prophylaxis were performed [ figures 1f , 2b , and 3b ] .
surgeon , clinical examiner , and patients were unaware of the group conditions of each patient .
patients were called for measurement and photographic documentation pre - surgically and 1 , 2 , 3 , and 6 months post - operatively .
measurements were made using a periodontal probe and rounded off to the nearest millimeter . at baseline and 1 , 2 , 3 , and 6 months after surgical treatment , the following parameters were recorded : recession depth ( rd ) was measured at the point of the deepest recession from the cej to the gingival margin .
pd was the distance to which an ad hoc instrument ( probe ) penetrates into the pocket .
clinical attachment level ( cal ) was the distance from the cej to the base of the pocket and was calculated by combining pd and rd measurements .
height of keratinized gingiva ( hkg ) was measured from the gingival margin to the mucogingival junction at the same point as the rd .
plaque score was recorded using the plaque control record ( pcr ) ( oleary plaque index ) .
the surgical treatment for each patient was done only when the pcr reached was below 20% [ figure 4 ] .
age , rd , cal , pd , and hkg before treatment and after 6 months among study groups were compared by one - way anova followed by the tukey test .
figure 4 shows flowchart of study . of 33 reviewed patients , 6 were not eligible ( 2
did not meet inclusion criteria and 4 patients refused informed consent ) and did not enter the study . finally , 27 patients with 66 gingival recessions in 3 groups completed the study and analyzed .
comparison of means of rd among study groups before and 6 months after intervention are summarized in table 1 . as shown ,
six months later , no significant differences were noted between controls with test groups , but in group i rd was significantly lower than group ii .
rd changes were statistically different between group i and two other groups but rd change was not statistically different between group ii and control group .
percentage of root coverage in group i was significantly higher than in groups ii and iii , but there was no significant difference between groups ii and iii .
the clinical results of a representative case are shown in figures 1e , 2b , and 3b .
recession depth during trial period in studied groups table 2 shows the clinical variables at baseline and 6 months after treatment .
differences in the mean of cal , ppd , and hkg among study groups at baseline were not statistically significant .
cal 6 months after treatment and gain after 6 months among the three groups was significant .
ppd and hkg among the study groups 6 months after treatment and gain after 6 months were not statistically significant .
the results of the present study showed that all treatment modalities ( edta + cpf , citric acid + cpf , and cpf alone ) can produce significant improvements in the studied clinical parameters with respect to baseline .
also , our results demonstrated that there was a significant difference for rd between the edta and acid group and also between the edta and control group .
several studies have compared the effect of emdogain ( emd ) and edta gel and cpf for covering exposed root surfaces ; controversial results have been reported .
showed that topical application of emd and edta are beneficial in augmenting the effects of the cpf in terms of the amount of root coverage gained .
modica et al . reported that additional use of emd and edta , together with cpf technique for recession coverage showed no significant difference in overall clinical outcome .
several possible reasons may explain these controversies such as differences in methodology , duration of the study , and also data variability . in the present study , the relative values for root coverage expressed as a percentage after 6 months in the edta group showed it to be superior .
reported that the mean values for treatment success in the two treatment groups were 80% for experimental sites and 79% for control sites . in this study , while there was a significant difference between the edta and acid group for gingival recession coverage ( 80.13% vs. 52.6% ) , no statistically significant differences for gingival recession coverage were found between the acid and control group .
the relative values expressed as a percentage after 6 months for the acid and control group were 52.16% and 64.5% , respectively , and the absolute values of the change expressed in millimeter were also similar .
thus , there is no additional benefit for citric acid application on root surfaces for root coverage .
this is in accordance with some other studies and suggests that , low ph etching agents such as citric acid exerts an immediate ( within 20 s ) necrotizing effect on both mucosal flaps and periodontal tissue .
thus , the superficial necrotizing effect on exposed periodontal tissues by citric acid in the present study may have restricted the healing potential of these tissues while etching at neutral ph ( edta gel ) may be argued to enhanced periodontal healing by inducing less adverse effects and consequently making full use of the healing potential of surrounding periodontal tissues .
the cal was improved by reduction of rd and ppd in the edta and control group after 6 months .
this is in accordance with other studies and suggests that recession coverage by cpf procedure does not result in pocket formation but in tissue attachment on the previously exposed root surface ; to facilitate this tissue attachment it has been advocated to condition the root surfaces with agents with a neutral ph .
these agents such as edta gel 24% may be able to produce a biocompatible surface more conductive to periodontal membrane cell colonization after removal of root surface smear without compromising the vitality of the surrounding periodontium .
on the other hand , acidic etching agents such as citric acid ( ph = 1 ) was able to dissolves the mineral component of the roots and erodes the collagenous matrix and may not only be unable to produce additional new attachment but may also exert an immediate necrotizing effect on the periodontium .
the clinical significance of attached gingival width is questionable , as the dimensions of the keratinized tissue are not related to the health and stability of the gingival tissues .
wennstrom and zucchelli suggested that tooth brushing habits may be of greater importance for maintenance of the surgically established position of the gingival margin .
long - term clinical studies are needed to evaluate the long - term clinical effects of the application of edta gel 24% and the stability of the results achieved .
, one can not draw conclusions regarding the type of attachment that was gained based on clinical measurements .
in conclusion , our results demonstrated that root preparation with edta is an effective procedure to cover localized gingival recessions ; use of edta significantly improved the amount of root coverage obtained ; long - term clinical studies are needed to evaluate the long - term clinical effects and stability of the results achieved .
Output:
| background : localized gingival recession can be treated successfully via coronally positioned flap ( cpf ) and additional use of root surface demineralization agents .
the purpose of this study was to evaluate the effects of additional use of ethylene diamine tetraacetic acid ( edta ) and citric acid as a root conditioner in association with cpf to cover localized buccal gingival recessions.materials and methods : twenty - seven patients with 66 miller class i buccal gingival recession 2 mm on single - rooted teeth were studied .
patients were randomly assigned : cpf with edta gel ( test 1 ) and cpf with saturated citric acid ( test 2 ) or cpf alone ( control ) .
clinical parameters were measured at baseline and 1 , 2 , 3 and 6 months after surgery ; assessment included recession depth ( rd ) , clinical attachment level ( cal ) , probing depth ( pd ) and height of keratinized gingiva ( hkg ) .
spss version-20 was used to perform all statistical analyses .
data was reported as mean sd .
age , rd , cal , pd , and hkg before treatment and after 6 months among study groups were compared by one - way anova followed by the tukey test .
the level of significance was considered to be less than 0.05.results:at 6 months , all treatment modalities showed significant root coverage and gain in cal .
rd was reduced from 2.86 0.76 mm to 0.550.53 mm in the edta group and from 2.370.57 mm to 1.030.43 mm in the acid group and from 2.370.54 mm to 0.850.49 mm in the control group . the average percentage of root coverage for the edta , acid , and control groups were 80.73% , 52.16% , and 64.50% , respectively . at 6 months
, there was a significant difference ( p
< 0.05 ) in all parameters for the edta group ( except hkg that did not vary among the groups).conclusion : root preparation with edta was an effective procedure to cover localized gingival recessions and significantly improved the amount of root coverage obtained . |
PubmedSumm6583 | ***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
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***EXAMPLES***
Input: genetics and environmental factors combine to produce different asthma phenotypes and various responses to controller medications .
the global initiative for asthma ( gina ) updated in 20161 is an ongoing international effort to provide a unified approach to the diagnosis and treatment of asthma .
table 1 summarizes the gina general treatment approach to asthma that uses a stepwise function based on the severity of asthma symptoms .
the table shows that inhaled corticosteroids ( icss ) play a major role as maintenance or preventative treatments in this stepwise approach to asthma .
table 2 summarizes the currently available and approved handheld inhalers by the us food and drug administration ( fda ) and several others not available in the usa .
fluticasone furoate ( ff ) is a potent corticosteroid that is dosed once daily due to its long half - life when inhaled .
it was approved by the fda as a once - daily ics for the maintenance treatment of asthma as a dry powder inhaler ( dpi ) in august 2014 with the brand name arnuity ellipta ( gsk , usa).2 controversy exists as to the role of long - acting beta2 agonists ( labas ) in the maintenance treatment of moderate to severe asthmatics .
early clinical trials of the laba salmeterol ( sal ) noted a nonstatistically significant increase in all - cause mortality in asthmatic patients treated over 16 weeks when compared to those using the short - acting beta2 agonist ( saba ) , albuterol.3 a large 2006 clinical trial of 26,355 asthmatics named the salmeterol multicenter asthma research trial ( smart ) evaluated sal by metered dose inhaler ( mdi ) compared to placebo mdi over 28 weeks.4 the use of ics and leukotriene modifiers was equal in both groups ( 47% and 11% , respectively ) .
the primary outcome included respiratory - related deaths or life - threatening events , and both were infrequent for the sal group ( 50 patients ) and placebo group ( 36 patients ) .
this difference did not reach statistical significance ( relative risk [ rr ] = 1.40 , 95% confidence interval [ ci ] = 0.912.14 ) . when secondary outcomes were explored , a small but significant increase in respiratory - related deaths was found in the sal group ( sal 24 vs placebo 11 ; rr = 2.16 , 95% ci = 1.064.41 ) along with specific asthma - related deaths ( sal 13 vs placebo 3 ; rr = 4.37 , 95% ci = 1.2515.4 ) .
the secondary outcome imbalances were largely related to the effects on the african - american subpopulation ( 20 sal vs 5 placebo ; rr = 4.92 , 95% ci = 1.5410.90).4 this study and a few others resulted in the fda requiring a black box
warning for all inhaled laba agents based on the risk of their use in asthma .
recent studies have called into question if there is an increase in risk to asthmatic patients treated with a combination ics / laba inhaler . in 2016 , peters et al5 studied 11,693 adult and adolescent asthmatic patients 12 years of age for 26 weeks .
they were randomized to the ics budesonide alone or a fixed - dose combination of budesonide and the laba formoterol given twice daily by mdi .
the budesonide / formoterol ( bud / f ) combination was found to be noninferior to budesonide alone with 43 patients having a serious asthma - related event in the bud / f group and 40 patients in the budesonide - alone - treated group ( hazard ratio [ hr ] = 1.07 , 95% ci = 0.701.65 ) . the risk of an asthma exacerbation was 16.5% lower in the bud / f - treated group compared to the budesonide - alone - treated group ( hr = 0.84 , 95% ci = 0.740.94).5 a similarly designed study in 11,679 asthmatic patients 12 years of age treated for 26 weeks also found that the combined fixed - dose fluticasone propionate ( fp)/sal did not have a significantly higher risk of serious asthma - related events and did have a 21% reduction in severe asthma exacerbations than those treated with fluticasone alone.6 similarly , when a fixed combination inhaler of sal and fp was compared to inhaled fp alone in 6,208 asthmatic children aged 411 years , non - inferiority for serious asthma - related events was seen ( hr = 1.28 , 95% ci = 0.732.27).7 these and other data suggest that the combination of an ics with laba is a safe and an effective treatment for asthma . furthermore , the use of both an ics and a laba is an integral part of the gina guidelines ( table 1 ) for the asthma patient at the step 3step 5 levels.1
table 2 summarizes the multiple handheld inhalers available in the usa . at this time
, laba monotherapy without the simultaneous use of an ics is still discouraged and has recently been described as medical negligence in children with asthma.8 the fixed combination of ff ( 100 or 200 g ) combined with the laba vilanterol trifenatate ( vi ; 25 g ) was approved in the usa in may 2013 for the maintenance treatment of chronic obstructive pulmonary disease ( copd ) as the once - daily dpi breo ellipta ( gsk , usa ) .
the same year , the same combination of drugs , doses and delivery system ( relvar ellipta ; gsk , uk ) was approved in japan and the european union for the treatment of asthma.9 breo ellipta ( ff [ 100 or 200 g]/vi [ 25 g ] ) was approved by the fda for the maintenance treatment of asthma in april 2015.2 this article reviews the data that support the use of the fixed - dose combination of dpi ff with vi as a once - daily asthma maintenance treatment .
the inhaled use of ff in asthma is in part based on its long half - life in the lung that allows once - daily dosing for asthma maintenance therapy.10 as given in table 1 , ics therapy plays a major role in the current gina guidelines .
when as - needed sabas become inadequate to control asthma symptoms , the use of low - dose ics should be considered as early as step 1 and used through step 2 into step 3 as medium- to high - dose ics .
the 100 g daily dpi dose of ff is considered low - dose ics therapy for asthmatics aged 12 years and older.1 after the addition of a laba to low - dose ics therapy at step 3 , higher medium- or high - dose ics therapy is recommended by the gina guidelines for asthmatic patients that remain symptomatic .
high - dose ics and can be used for symptomatic step 35 asthmatic patients.1 table 3 summarizes the major clinical trials that have examined the use of ff as an ics maintenance asthma therapy .
efficacy and safety have been verified with once - daily ff dosing in asthmatic patients in several studies .
an 8-week study of 545 adolescent and adult asthmatic patients demonstrated significant ( all p0.033 ) improvements with ff in pre - dose and placebo - adjusted forced expiratory volume at 1 second ( fev1 ) .
once - daily evening - dosed ff ( 400 g ) was also as effective as twice - daily dosing ( 200 g ) of the same total daily ff dose in improving placebo - adjusted fev1 ( 200 ml).11 in this study , the morning - dosed ff ( 400 g ) was found to be less effective than an equal dose of ff ( 200 g ) given twice daily ( 202 ml improvement , 95% ci = 96307 vs 315 ml improvement , 95% ci = 208421 ml).11 a randomized , double - blind , double - dummy and placebo - controlled study further evaluated once - daily ff ( 100 g ) given in the morning compared to the evening over a 2-week trial in asthmatics aged 1870 years who required an ics to control symptoms.12 inhaled ff ( 100 g ) daily increased 24-hour weighted mean fev1 relative to placebo ( for am dosing , 77 ml ; 90% ci = 1152 ml and for pm dosing , 105 ml ; 90% ci = 29180 ml)13 and found that the difference in the increase when ff was given in the morning or evening was negligible ( adjusted differences , 28 ml ; 90% ci = 10245 ml).12 a longer 24-week multicenter , double - blind , parallel - group study compared once - daily evening doses of ff ( 100 g ) to ff ( 200 g).13 both ff doses improved least - squares mean trough fev1 from baseline by 208 ml in the ff ( 100 g ) group and 284 ml in the ff ( 200 g ) group ( treatment difference , 77 ml ; 95% ci = 39192 ml).13 similar improvements were seen in rescue- and symptom - free days , morning and evening peak expiratory flow ( pef ) and reported adverse events with the two ff doses .
the 200 g ff - treated group was 42% more likely to have well - controlled symptoms than the 100 g ff - treated group .
there were no safety concerns , and no clinically relevant effects on 24-hour urinary cortisol levels with either of the doses of inhaled ff were found.13 when inhaled ff ( 100 g ) daily for 2 weeks was compared to ff ( 100 g ) combined with the long - acting muscarinic antagonist ( lama ) , umeclidinium ( umec ; 15.6 , 31.25 , 62.5 , 125 or 250 g ) , in adult asthmatics , trough fev1 was improved with ff ( 100 g ) alone ( by 87 ml ) compared to baseline , but they increased even more when ff ( 100 g ) was combined with umec doses ( 141214 ml).14 when least - squares mean change in trough fev1 was evaluated , statistically significant differences were seen with ff ( 100 g)/umec ( 125 and 250 g ; both 55 ml , p=0.018 ) compared to ff ( 100 g ) alone.14 in addition , both morning and evening pef improved more with the combination of ff with umec daily inhalation compared to ff alone .
the ff serum concentrations peaked at half an hour when given alone , and this did not change when combined with umec.15 the use of daily ff given by dpi has a proven efficacy in asthmatic patients requiring an ics for symptom control .
the combination of ff with lama appears to increase the efficacy compared to ff alone in asthmatic patients .
several new laba agents designed for once - daily dosing are available or under study including indacaterol , olodaterol , abediterol and vi.16 appropriate concern for the use of laba agents alone as maintenance therapy has mandated that asthmatic subjects in most clinical studies evaluating the use of the inhaled laba vi be currently on an ics ( table 4 ) .
an exception is the study by kempsford et al.17 inhaled vi was given once daily ( 25100 g ) for 14 days to healthy volunteers and once to patients with either asthma or copd .
inhaled vi was rapidly absorbed with a median time to maximal serum concentrations of 5 minutes in healthy subjects and 10 minutes for asthma and copd patients .
all vi doses improved fev1 by 5 minutes and maintained increased fev1 up to 24 hours after inhalation in patients with asthma or copd.17 no clinically significant adverse effects were found including evaluations of vital signs , 12-lead electrocardiogram ( ecg ) , holter ecg , blood glucose or potassium levels .
table 4 summarizes five placebo - controlled clinical trials in asthmatics on an ics that evaluated inhaled vi using a dpi device lasting between 1 and 12 weeks .
doses between 3 and 50 g daily of inhaled vi were tried , and the bronchodilator effect lasted at least 24 hours for vi doses 12.550 g.18 the efficacy and safety of once - daily vi dosing in asthmatics were established by sterling et al19 who evaluated 72 adult ( 18 years old ) asthmatics on an ics with a 7-day treatment of daily inhaled vi ( 6.25 , 12.5 and 25 g ) , twice - daily inhaled vi ( 6.25 g ) or placebo using a dpi . the vi treatment in asthmatics resulted in a statistically significant ( p<0.001 for all doses ) increase on day 7 in trough fev1 and weighted mean 24-hour fev1 versus placebo .
the differences from placebo for trough fev1 with once - daily vi were 94 ml ( 95% ci = 49140 ml ) , 102 ml ( 95% ci = 57147 ml ) and 125 ml ( 95% ci = 80170
the 6.25 g vi twice - daily dose resulted in 140 ml ( 95% ci = 95185 ml ) improvement in trough fev1 compared to placebo.19 non - inferiority between once - daily versus twice - daily vi dosing was also shown.19 a recent large trial children aged 511 years ( n=456 ) with persistent asthma symptoms inadequately controlled on an ics were randomized to once - daily inhaled vi ( 6.25 , 12.5 or 25 g ) , and this was compared to placebo over 4 weeks .
it demonstrated safety but failed to show an improvement from baseline in trough fev1 for any of the vi doses tested.20 adult asthmatic patients uncontrolled on an ics ( n=347 ) were given once - daily vi ( 25 g ) for 12 weeks and were compared to those given twice - daily sal or placebo .
researchers noted the improvement in fev1 of 35942.9 ml with vi , 28341.9 ml with sal and 28942.9 ml for placebo.21 the increase in fev1 was not statistically significantly different between vi and placebo .
overall , these data suggest that there is a variable response to inhaled vi in adult patients with persistent symptoms already on an ics and even less efficacy of vi in asthmatic children on an ics .
pharmacodynamic , pharmacokinetic and safety data have been tested with inhaled ff / vi in several populations , including healthy chinese and japanese , in patients simultaneously on ketoconazole and in patients with renal and hepatic impairment.2225 stable pharmacokinetics and pharmacodynamics and no safety concerns over the use of inhaled ff / vi were found in these studies .
allergen and methacholine challenge tests were used in 27 patients randomized to inhaled ff ( 100 g ) , vi ( 25 g ) , ff ( 100 g)/vi ( 25 g ) or placebo.26 using the allergen challenge to test early asthmatic response ( ear ) and airway hyperresponsiveness ( ahr ) , researchers found a decrease in fev1 . using the mean 02 hours post allergen challenge fev1 ,
the least decrease was reported with the pre - challenge dosing of the combination ff / vi inhaler ( 0.614 l , 95% ci = 0.858 to 0.370 ) and the greatest decrease was after placebo inhaler ( 1.091 l , 95% ci = 1.344 to 0.837 ) .
the methacholine challenge test was used in these patients to model late asthmatic response ( lar ) and ahr at 24 hours . weighted mean
fev1 410 hours post challenge was reduced after placebo ( 466 ml , 95% ci = 589 to 343 ) but actually increased with ff ( 100 g ; 18 ml , 95% ci = 89 to 125 ) and with ff ( 100 g)/vi ( 25 g ; 18 ml , 95% ci = 89 to 124 ) . it was also improved compared to placebo with vi ( 25 g ; 298 ml , 95% ci = 415 to 181).26 the use of the combined ff / vi provided statistically significant protection against the ear of ahr compared to its components alone and to placebo .
there was also statistically significant protection with combination ff / vi therapy when compared to placebo and vi alone against the lar of ahr .
cytochrome p450 3a4 ( cyp3a4 ) is the major hepatic enzyme responsible for metabolizing ff by ester hydrolysis with the formation of the 17 beta - carboxylic acid and loss of the s - fluoro - methyl - carbothioate.24,27 ff is also believed to be a substrate for the p - glycoprotein ( pgp ) efflux transporter , and enterocytes may have a major metabolic effect on ff in the gastrointestinal track.27 the hepatic enzyme cyp3a4 also plays a major role in the metabolism of vi by o - dealkylation.28 it is also believed to be a substrate for pgp when in the gastrointestinal system.24 ketoconazole is a probe used to assess the potential effect of cyp3a4 metabolic inhibition , and it also has inhibitory effects on pgp.24 coadministration of repeat doses of ketoconazole 400 mg daily and inhaled vi ( 25 g ) alone had no pharmacodynamic or pharmacokinetic effect on vi .
when 11 days of 400 mg oral ketoconazole daily was coadministered with inhaled ff ( 200 g)/vi ( 25 g ) from days 5 to 11 , no statistical or clinical effect was seen on heart rate or minimal potassium levels.24 there was a 27% decrease in 24-hour weighted mean serum cortisol levels ( treatment ratio = 0.73 , 90% ci = 0.620.86 ) .
an increase in the ff area under the plasma concentration 024-hour curve by 36% with ketoconazole ( 90% ci = 16%59% ) was reported .
the area under the plasma concentration 024-hour vi curve increased by 65% ( 90% ci = 38%97%).24
table 5 summarizes the major pharmacokinetic parameters of ff and vi that allow once - daily dosing for this inhaled fixed combination medication .
table 6 summarizes the major clinical trials evaluating pharmacokinetics , safety and efficacy of ff / vi given by dpi in asthmatic patients .
large randomized double - blind clinical trials have shown improved fev1 and pef measures by treatment with ff / vi compared to placebo or the same or better measures with active control agents such as inhaled fp and fp with the laba sal twice daily.2936 these clinical trials lasted from 2 to 52 weeks and evaluated efficacy and safety . two trials
each of 12-week duration have confirmed the efficacy of ff ( 100200 g)/vi ( 25 g ) given daily by dpi in asian asthmatic patients compared to placebo37 and compared to the active comparator fp using pef measures of efficacy.38 an observational study from italian national health service data used propensity score matching on baseline covariates of gender , age , fev1 and comorbidities on 40 adult asthmatic patients .
they were treated with ff ( 100 g)/vi ( 25 g ) by dpi once daily or beclomethasone dipropionate / formoterol ( bec / f ) inhalation twice daily.39 the bec / f - treated group had 0.28 ( 0.12 ) days of hospitalization , and those treated with ff / vi had 0.08 ( 0.04 ) days of hospitalization ( p=0.09 ) during the 12-week analysis period .
both the number of physician visits and the number of specialist visits were statistically reduced in the ff / vi - treated group compared to the bec / f - treated group.39 another small comparison study ( n=30 ) in japan evaluated bud ( 160 g)/f ( 4.5 g ) two puffs twice daily and one additional inhalation as needed of bud / f each day versus ff ( 100 g)/vi ( 25 g ) by dpi daily over 4 weeks in asthmatics 20 years who required an ics.40 both drug combinations showed statistically significant ( p<0.001 ) improvement in the asthma control questionnaire during the 4 weeks with greater improvement in the scores with the bud / f - treated group .
both groups also showed decreases ( p<0.001 ) in fractional exhaled nitric oxide ( feno ) from baseline to week 4 with the levels in the bud / f group reduced greater ( p<0.001 ) than the ff / vi - treated group .
the use of a fixed - dose ics / laba as a rescue medication in this study goes against historical dogma of using saba agents as rescue medication in asthma but is in the gina guidelines ( table 1 ) .
in addition , direct comparisons between different combinations of ics / laba beg the question of dosage equivalence . in this study ,
perhaps the comparator should have been ff ( 200 g)/vi ( 25 g ) as a high - dose ics as opposed to the low - dose ff ( 100 g)/vi ( 25 g ) combination . the asthma copd overlap syndrome ( acos ) is an asthma phenotype that shares features of both asthma and traditional copd.1,41 a small ( n=16 ) open - label , randomized , crossover study of patients with acos in japan compared once - daily ff ( 200 g)/vi ( 25 g ) versus fp ( 500 g)/sal ( 50 g ) twice daily for 4-week treatment periods.42 the mean value of fev1 was 1.33 l ( 1.29 ) during the run - in period , 138 l ( 0.39 ) after the fp / sal treatment and 1.47 ( 0.38 ) l after the ff / vi treatment .
the mean value of fev1 was significantly ( p<0.01 ) greater in the ff / vi treatment group compared to the run - in period in these patients with acos .
although a small trial of short duration , it is one of the few pharmacological trials in patients with acos and the only randomized trial evaluating the ff / vi combination inhaler in patients with acos phenotype . a large pragmatic study evaluating ff ( 100 or 200 g)/vi ( 25 g )
the salford lung study is a randomized and controlled trial started before ff / vi inhalers were approved for asthma treatment .
it utilizes the salford electronic medical record to give near real - time data collection and monitoring of safety data at 66 primary care sites in and around salford and south manchester , england.43 the data from this study when available will complement the more standard double - blind , randomized , controlled trials evaluating real - world efficacy and obtaining risk / benefit information on inhaled ff / vi . when east asian patients were compared to non - east asian patients from the large randomized , double - blind , multicenter clinical trials in a prespecified subgroup analysis ,
both ff ( 100 or 200 g)/vi ( 25 g ) dose combinations were as effective in improving fev1 compared to placebo as in non - east asian patients.44 a systematic review with meta - analysis of seven published trials ( n=5,668 ) evaluating inhaled ff / vi in asthmatic patients was recently performed.45 the combination therapy of ff ( 100 or 200 g)/vi ( 25 g ) daily increased trough fev1 in asthmatics treated longer than 8 weeks compared to either fp twice daily or ff daily alone .
three of the seven trials compared ff ( 100 or 200 g)/vi ( 25 g ) doses to ff ( 100 g ) once daily and showed a significant ( p0.001 ) increase in trough fev1 of 90 ml ( 95% ci = 60120 ml ) with the combination inhaler compared to ff alone.45
medication adherence or following the medication plan is a significant problem and factor in the treatment of chronic diseases.46 dosing frequency has a major effect on the rate of nonadherence of medication in chronic diseases.47 when medications are given twice daily compared to once daily , the adherence rates were significantly lower , with regimen adherence reduced by 13.1% and timing adherence reduced by 26.7% compared to once daily.47 the adherence rates fall 23.1% for regimen adherence and 54.2% for timing adherence when medications are given four times daily compared to daily dosing .
nonadherence to treatment is associated with poor baseline asthma control.48,49 the nonadherence rates among asthmatic patients range between 30% and 70% , and because of this the assessment of medication adherence is a critical part of evaluating the difficult to treat asthma patient.50,51 integrated and innovative approaches to patients are needed to improve medication adherence in difficult asthmatic patients.52 once - daily medications and the combination of an ics with a laba in a single inhaler are associated with improved medication adherence compared to that of an ics alone.53,54 better medication adherence must be addressed and will improve health outcomes and asthma disease control.55,56 in addition to being a daily combination dosing asthma maintenance medication , breo ellipta ( gsk ) utilizes the ellipta delivery system .
the ellipta dry powder system ( gsk , uk and japan ) has been shown to be easy to use and preferred over the breezhaler ( novartis pharma uk , japan ) in device - naive japanese volunteers.57 when semi - structured , in - depth , qualitative interviews were conducted on asthma and copd patients after using ellipta ( gsk , germany ) dry powder inhalation systems , the ellipta device was associated with the highest patient satisfaction and preference.58 patient preference for the ellipta device was also demonstrated in 287 copd patients randomized to the ellipta or diskus dpis.59 the ellipta device was significantly preferred ( p<0.001 ) over the diskus device in all categories .
overall inhaler preference was 67% for the ellipta device and 31% for the diskus.59 once - daily dosing with the ff / vi ellipta device and its high patient preference are also likely to contribute to improved asthma medication adherence .
to date , a large amount of clinical trial data exists supporting the efficacy and safety of the use of inhaled ff / vi by dpi for asthma maintenance treatment .
the combination ics / laba of ff / vi fits well into the gina guidelines starting as early as step 3.1 studies looking at a fixed - dose triple - combination inhaler with ff , vi and the lama umec are ongoing in healthy volunteers , being developed for copd indication and could be evaluated in asthmatic patients.60
the dpi inhaler , ff / vi , is a fixed combination of two strengths of ff ( 100 or 200 g ) both with vi ( 25 g ) used as a maintenance treatment in asthmatic patients not controlled on just an ics therapy alone .
the doses of ff cover low- and high - dose ics categories and fit nicely into the current gina asthma treatment guidelines .
similarly , efficacy and safety were demonstrated in clinical trials in adolescent and adult asthmatic patients on an ics with adding inhaled vi but not in children aged 511 years .
the data supporting the combined use of ff / vi in asthmatic patients requiring ics are strong and document its efficacy and safety in long - term , large and randomized clinical trials in adolescents and adults .
pharmacokinetics and pharmacodynamics have been well studied and have demonstrated limited clinically important drug interactions ( eg , ketoconazole ) and minimal alterations from renal and liver impairments .
limited efficacy data with inhaled ff / vi exist for asthmatic children ( < 12 years ) .
further studies on asthmatic children and various asthma phenotypes such as patients with acos are needed to better understand the full spectrum of the use of inhaled fixed combination ff / vi in the maintenance treatment of asthma .
Output:
| the use of inhaled corticosteroids ( icss ) plays a key role in the treatment of asthmatic patients , and international guidelines have designated icss as an early maintenance therapy in controlling asthma symptoms .
when asthmatic patients remain symptomatic on icss , one common option is to add a long - acting beta2 agonist ( laba ) to the maintenance treatment .
fixed combination inhalers that contain both an ics and a laba have been popular for both chronic obstructive pulmonary disease ( copd ) and asthma .
historically , these inhalers have been dosed twice daily .
however , currently , there is a once - daily combination therapy with the ics fluticasone furoate ( ff ) and the laba vilanterol trifenatate ( vi ) with indications for use in both copd and asthma .
this dry powder inhaler ( dpi ) comes in two doses of ff ( 100 or 200 g ) both combined with vi ( 25 g ) .
this article reviews the clinical trial data for ff , vi and ff / vi combination inhalers and documents the efficacy and safety of once - daily inhaled maintenance therapy by dpi in asthmatic patients . |
PubmedSumm6584 | ***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: immunoglobulin e ( ige ) predominantly mediates immunity and immune responses against parasitic infections , but it is also an essential component of type i hypersensitivity reaction , which can cause anaphylaxis , asthma , atopic dermatitis , and allergic rhinitis [ 2 , 3 ] .
inhalant and food allergies are induced and regulated by ige and can be present in children and adults with frequent or chronic upper respiratory inflammatory episodes that are often misdiagnosed as viral infections .
allergy is increasingly common worldwide : 20%25% of adults reportedly have an allergy - based respiratory disease , and up to 40% of children in western countries may be affected [ 68 ] .
children who are genetically prone to atopy commonly present with eczema up to the age of 3 years , after which asthma and rhinitis develop as the next stage of the atopic march .
the most effective treatment is prompt diagnosis followed by the identification of specific causative allergen(s ) .
the gold standard for the detection of specific allergens is the immunocap immunoassay , but this method can be costly and requires specialist equipment and skill .
many immunologists therefore initially assess the total ige levels in patients with suspected allergies , despite the reported low negative predictive value of this assay [ 1013 ] .
currently , the measurement of total ige is recommended only as a supplemental diagnostic measure for the diagnosis of allergic asthma .
however , this investigation is widely used by clinicians in the middle east , including those in saudi arabia , even though the efficacy and cost - effectiveness of assessing total ige remain unclear .
this study aimed to assess the predictive value of total ige in a group of patients with suspected allergies in saudi arabia , in order to determine whether this test is useful as a diagnostic tool in this population .
moreover , the predictive value of total ige was determined separately for inhalant , food , and multiple allergies , in order to verify which type of allergy is more specifically associated with high total ige levels .
this retrospective study was carried out at king abdulaziz university hospital ( kauh ) , which is the referral medical center in the western region of saudi arabia .
the electronic records of all patients who presented between january 2013 and december 2014 to the outpatient or inpatient clinics of kauh with clinical suspicion of food or inhalant allergy were analyzed .
the protocol of this study was approved by the biomedical research ethics committee of king abdulaziz university .
patients were suspected for allergy based on a history of significant skin , digestive , or respiratory reaction concomitant to the exposure to any potential food or inhalant allergen .
total ige level was determined using unicap 100 ( pharmacia ab diagnostics , uppsala , sweden ) .
the results were collected as a continuous variable ( ku / l ) and the test was defined as positive for a value > 195
the identification of specific allergens was considered to be the golden standard and was carried out using the immunocap technology ( phadia inc . , uppsala , sweden ) . based on the characteristics of our study population , specific allergen groups that were used in immunocap included phad , hx2 , or mx1 in inhalant allergies and fx2 , fx3 , or fx5 in food allergies .
for both total ige and immunocap assays , blood samples were collected in plain tubes ( without anticoagulant ) . according to patient 's history and clinical presentation ,
the population was divided into two groups : patients with suspected food allergy ( group a ) and those with suspected inhalant allergy ( group b ) . a pooled analysis of the two groups
was first carried out to determine the overall diagnostic value of total ige in allergy regardless of its type .
afterwards , groups a and b were analyzed apart to determine the diagnostic value of total ige in food and inhalant allergies , separately .
in both pooled and separate analyses , subjects with positive allergen detection ( positive results in immunocap ) were analyzed as cases and those with negative allergen detection ( negative results in immunocap ) were analyzed as controls . finally , subjects with two or more allergens identified in immunocap were compared to those with only one allergen identified , in order to assess the predictive value of total ige in multiple allergy disorders .
statistical analysis was performed in statistical package for social sciences version 16.0 for windows ( spss inc . ,
the sensitivity , specificity , positive predictive value ( ppv ) , negative predictive value ( npv ) , positive likelihood ratio ( + lr ) , and negative likelihood ratio ( lr ) of total ige level were determined in the following different clinical situations : ( a ) for any allergy suspected regardless of its type ( groups a + b ) ; ( b ) suspected food allergy ( group a ) ; ( c ) suspected inhalant allergy ( group b ) ; and ( d ) screening for multiple allergies in patients with one known allergen . receiver operator characteristic ( roc ) curves were drawn and the area under the curve ( auc ) was measured to study the diagnostic value of total ige in all four previous clinical situations . as previously specified , subjects were analyzed as cases or controls as per their results ( positive or negative ) in immunocap assay .
furthermore , subjects were divided into different categories as per the number of specific allergens detected and mean ige level was compared between these categories , using independent t - test or one - way analysis of variance ( one - way anova ) as appropriate .
finally , logistic regression was carried out using the presence of an allergen on the immunocap assay as the categorical variable , total ige level as the continuous variable , and sex and age as independent variables .
the medical records of 2641 patients were analyzed , among whom a total of 1893 ( 71.7% ) were eligible for the study . with regard to the clinical presentation
, there were 300 cases of suspicion of food allergies ( group a : 60.7% males , age ( mean sd ) = 34.3 20.4 years ) and 1604 cases of suspected inhalant allergies ( group b : 40.5% males , age ( mean sd ) = 38.5 19.1 years ) ; however , 11 patients presented twice , once with a suspicion of inhalant allergy and another time with a suspicion of food allergy , and were thus included in both groups in respective separate analysis . on the other hand , cases with ultimate positivity to both foods and inhalant allergens during the same visit were included and analyzed in their respective groups according to the clinical presentation .
patients were from a range of national backgrounds , including saudi arabia , other middle east countries , asia , and africa ( table 1 ) . in the pooled analysis ( n = 1893 ) , 482 ( 25.5% ) subjects tested negative in total ige assay ( 195
ku / l ) , among whom 143 were false negatives as they tested positive for either food or inhalant allergens on immunocap .
thus , total ige assay had an overall sensitivity of 61.3% , specificity of 83.4% , ppv of 80.6% , npv of 65.8% , + lr of 3.69 , and lr of 0.46 . in separate analysis ,
total ige assay had a relatively higher ppv ( 79.1% ) in inhalant allergies than in food allergies ( 54.4% ) and , conversely , a relatively higher ( 84.6% ) npv in food allergies than in inhalant allergies ( 67.9% ) .
further , the + lr and lr values were comparable for both inhalant and food allergies ( table 2 ) .
comparison of means between cases and controls showed a mean total ige level of 734.7 ku / l ( n = 798 , median = 271.0 , sem = 51.4 ) versus 122.1 ku / l ( n = 806 , median = 50.0 , sem = 8.9 ) in inhalant allergy , respectively ( p < 0.001 ) , and 755.2 ku / l ( n = 77 , median = 252.0 , sem = 152.7 ) versus 142.1 ku / l ( n = 223 , median = 52.0 , sem = 21.1 ) in food allergy , respectively ( p < 0.001 ) .
roc curve analysis of the diagnostic value of total ige showed an area under the curve ( auc ) = 0.770 ( 95% ci = 0.7070.833 , p <
0.001 ) in food allergies and auc = 0.817 ( 95% ci = 0.7960.837 , p < 0.001 ) in inhalant allergies ( figure 1 ) .
one - way analysis of variance ( anova ) showed that total ige level significantly increased with the number of concomitant allergies ( p < 0.001 ) ( figure 2 ) .
the sensitivity of total ige was higher ( 78.6% ) in screening for multiple allergens in patients with an already diagnosed allergen than in the primary diagnosis of any type of allergy ( 61.3% ) , inhalant allergy ( 59.6% ) , or food allergy ( 55.8% ) .
conversely , its specificity in screening for multiple allergens is weak ( 41.8% ) , in comparison with the other diagnoses .
however , a negative total ige assay ( 195 ui / ml ) predicts at 91.5% the absence of another allergen in subjects where an allergen was already detected ( table 2 ) .
roc curve analysis was carried out to assess the diagnostic value of total ige in multiple allergies in two clinical situations : ( a ) in patients with an unknown allergic status ( auc = 0.762 ( 95% ci = 0.7260.799 ) , p < 0.001 ) and ( b ) in patients already known as allergic for one allergen ( auc = 0.636 ( 95% ci = 0.5880.684 ) , p < 0.001 ) ( figure 3 ) .
sensitivity diminishes considerably with increase in the value of total ige used as a cut - off , while specificity increases in parallel .
further , the ppv of total ige is weak ( up to 40% ) even for high cut - off values .
npv is the only constantly good diagnostic parameter ( > 84% ) , which means that a low total ige in a patient with an already detected allergen is highly predictive of the absence of other simultaneous allergens ( figure 4 ) .
logistic regression analysis showed that age ( p = 0.155 ) and sex ( p = 0.322 ) were independent of the presence of an allergy and did not influence the correlation between the presence of a true allergy and the total ige assay results .
similarly , nationality did not impact the results ( p = 0.87 ) , most probably because all groups except for saudi arabians were small in number .
furthermore , the ability to exclude atopy as a cause of the symptoms is particularly important so that treatments with significant side effects are not used spuriously .
most allergy clinicians in the middle east still order total ige assays for patients with suspected allergies and only proceed to specific allergy testing if the total ige level is above a certain cut - off , which varies depending on the center .
this study provides evidence that the measurement of total ige has relatively low levels of both sensitivity and specificity .
this translates into the fact that , in almost 20% of the cases , high total ige levels do not indicate an allergy and , in up to 44% of the cases , normal levels do not necessarily indicate the absence of allergy .
wide et al . reported the first ige detection tool in 1967 , which was superseded shortly thereafter by phadebas rast ( radioallergosorbent test , pharmacia diagnostics ) , which measured ige against specific allergens quantitatively .
the current gold standard for assessing allergen - specific ige in plasma or serum samples is the immunocap specific ige test .
allergens of interest react with enzyme - labelled ige - specific antibodies , resulting in a measurable fluorescence reaction .
such reactions can be conducted on an automated platform that enables hundreds of samples to be processed in a precise and reproducible manner .
the immunocap platform is a highly sensitive and specific automated assay that is widely used worldwide for the diagnosis of allergies , but the cost and specialist technology required for the analysis mean that , in most cases , a total ige assay is performed first as a screening tool before specific allergen tests are performed .
one of the first studies to assess the sensitivity of total ige screening for nonspecific allergens was conducted in 2004 , and it showed that screening for specific allergens was not indicated if the total ige value was < 10 ku / l .
however , in this study , 3 out of 73 patients with values < 10 ku / l were positive for specific allergens .
the cut - off used in the present study for the total ige assay was 195
this value was based on the protocol adopted by our biochemistry laboratory at king abdulaziz hospital , but no study has so far investigated this cut - off level .
the cut - off is slightly higher than that published previously for ige , notably the cut - off of 183 ku / l by campos et al . and 169 ku / l by carosso et al .
however , the normal range of total ige can vary between ethnic groups , and those in the middle east tend to have higher levels of circulating ige than western populations [ 21 , 22 ] . in this study , we could not determine the influence of ethnicity as the majority of the population was from saudi arabia , and the nationality can not accurately indicate the ethnicity .
in addition to the influence of ethnicity , total ige levels vary depending on geographic area , smoking , and age . sex was also reported to be an influencing factor , with higher mean levels of total ige found in a cohort of boys compared to girls in a study from south korea .
however , we found no difference in cross gender comparison of means in total ige levels nor in logistic regression .
moreover , we did not find age to have a significant influence on the ige levels . in this study ,
when we analyzed food and inhalant allergies separately , we found that the total ige level had a higher ppv for inhalant allergies ( 79.1% ) than for food allergies ( 54.4% ) , while it had a higher npv for food allergies ( 84.6% ) than for inhalant allergies ( 67.9% ) .
further , the diagnostic value was relatively higher for inhalant allergies than for food allergies in roc curves , but we can not conclude to the efficacy of use of total ige as a diagnostic test for inhalant allergies .
we also determined the specificity and sensitivity of the total ige level for the diagnosis of multiple allergies .
the sensitivity of total ige ( cut - off > 195 ui ) in diagnosing multiple allergens was higher than that in the primary diagnosis of any type of allergy .
expectedly , when different values of total ige levels were analyzed as cut - offs in the diagnosis of multiple allergies in patients with a known allergy , we found that sensitivity decreases for higher values and specificity decreases for lower values .
practically , in patients with a documented allergen , even very high levels of total ige are a poor indicator of the existence of another allergen . however , in case of identification of multiple allergens , total ige showed efficacy in monitoring the efficacy of polydesensitisation methods , such as ifn - gamma therapy , where a decrease in total ige levels significantly indicated an improvement in the polysensitised status .
further , our study showed that npv of total ige ( 91.5% ) was best in the diagnosis of multiple allergies , which means that a low total ige level in a patient with one known allergen is highly predictive of the absence of a second allergen .
thus , total ige could be helpful to rule out a polysensitisation syndrome in patients where a specific allergen has already been diagnosed .
this can be especially indicated when the clinical context is not conclusive enough to guide further specific allergens identification . however
as this was a retrospective design , many confounders could not be collected and analyzed , such as smoking that could have been a major confounder for increased serum total ige levels [ 21 , 24 ] . a prospective controlled trial that assesses the outcomes after
the results of this study indicate that total ige assay is not efficient as a diagnostic test for allergy diagnosis in saudi patients , especially in food allergies .
the best diagnostic strategy in allergology should refer to the proper selection and interpretation of specific ige testing , sustained by a comprehensive atopic history of the patient .
nevertheless , total ige could be proposed in ruling out multiple allergic disorders in case of one specific allergen identification in patients with nonconclusive history .
Output:
| objective . to assess the diagnostic significance of total ige in foods , inhalant , and multiple allergies . methods .
retrospective review of the laboratory records of patients who presented with clinical suspicion of food or inhalant allergy between january 2013 and december 2014 .
total ige level was defined as positive for a value > 195
ku / l ; and diagnosis was confirmed by the detection of specific ige ( golden standard ) for at least one food or inhalant allergen and at least two allergens in multiple allergies .
results .
a total of 1893 ( male ratio = 0.68 , mean age = 39.0 19.2 years ) patients were included .
total ige had comparable sensitivity ( 55.8% versus 59.6% ) and specificity ( 83.9% versus 84.4% ) in food versus inhalant allergy , respectively , but a superior ppv in inhalant allergy ( 79.1% versus 54.4% ) .
roc curve analysis showed a better diagnostic value in inhalant allergies ( auc = 0.817 ( 95% ci = 0.7960.837 ) versus 0.770 ( 95% ci = 0.7070.833 ) ) . in multiple allergies ,
total ige had a relatively good sensitivity ( 78.6% ) , while negative ige testing ( < 195
ku / l ) predicted the absence of multiple allergies with 91.5% certitude .
conclusion .
total ige assay is not efficient as a diagnostic test for foods , inhalant , or multiple allergies .
the best strategy should refer to specific ige testing guided by a comprehensive atopic history . |
PubmedSumm6585 | ***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:
| occupational and toxicological studies have demonstrated adverse health effects from exposure to toxic air contaminants .
data on outdoor levels of toxic air contaminants have not been available for most communities in the united states , making it difficult to assess the potential for adverse human health effects from general population exposures .
emissions data from stationary and mobile sources are used in an atmospheric dispersion model to estimate outdoor concentrations of 148 toxic air contaminants for each of the 60,803 census tracts in the contiguous united states for 1990 .
outdoor concentrations of air toxics were compared to previously defined benchmark concentrations for cancer and noncancer health effects .
benchmark concentrations are based on standard toxicological references and represent air toxic levels above which health risks may occur . the number of benchmark concentrations exceeded by modeled concentrations ranged from 8 to 32 per census tract , with a mean of 14 . estimated concentrations of benzene , formaldehyde , and 1,3-butadiene were greater than cancer benchmark concentrations in over 90% of the census tracts .
approximately 10% of all census tracts had estimated concentrations of one or more carcinogenic haps greater than a 1-in-10,000 risk level .
twenty - two pollutants with chronic toxicity benchmark concentrations had modeled concentrations in excess of these benchmarks , and approximately 200 census tracts had a modeled concentration 100 times the benchmark for at least one of these pollutants .
this comprehensive assessment of air toxics concentrations across the united states indicates hazardous air pollutants may pose a potential public health problem.imagesfigure 1figure 2figure 3figure 4 |
PubmedSumm6586 | ***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: ameloblastic fibroodontomas ( afos ) are slow - growing , benign tumors developing from the odontogenic epithelium and ectomesenchyme .
they are usually found to be asymptomatic and are most often discovered on routine radiography .
the clinical features are painless swelling of the jaw , an asymmetrical face , missing permanent teeth , and displaced or impacted tooth .
radiographically , such a tumor appears as a well - circumscribed , expansile radiolucency that generally contains solitary or multiple small radiopaque foci .
the presence of radiopaque material ranging from small spots to extensive compact masses in the center of the tumor image is common .
we present a case of an 18-year - old female with giant complex odontoma present in the body of the mandible leading to an impacted mandibular third molar .
an 18-year - old female presented to our unit with the complaint of a painless swelling on the left side of the lower jaw for the last 3 years that seemed to show a progressive increase in size . on examination , a firm , diffuse , nontender swelling of size 9 5 cm involving the left body of the mandible was observed [ figure 1 ] .
on intraoral examination , a small hard tissue projecting over the posterior alveolus was present with normal surrounding mucosa . to our surprise ,
the orthopantomogram ( opg ) showed a well - defined radiopaque mass of size 3 6 cm present over the left body of the mandible .
an impacted third molar was present below the mass just above the inferior border [ figure 3 ] .
preoperative photograph showing diffuse swelling over the left side of the lower face intraoral photograph showing missing permanent left mandibular molars and a calcified , toothlike structure protruding from the alveolar mucosa over the retromolar region orthopantomogram revealsa large , well - defined radiopaque lesion with focal radiolucent areas occupying the whole left body of the mandible . an impacted tooth is also visible .
this appearance suggests that the lesion is a complex odontoma we planned surgical removal of the tumor along with the impacted third molar under general anesthesia .
the tumor was approached via submandibular incision , followed by layer - wise dissection to reach the inferior border of the mandible .
after reflection of the periosteal layer , the expanded buccal cortex was seen . with the help of a chisel and mallet , the outer cortical bone overlying the tumor
the lingual cortical bone was found to be intact [ figures 4 and 5 ] .
the reconstruction of the defect was done with nonvascularized corticocancellous iliac crest bone , which was taken from the contralateral side [ figure 6 ] . the fixation of the graft was done with 2 - 0 vicryl sutures to prevent any unnecessary hardware fixation or thermal injury to it . after achieving proper hemostasis , closure was done in layers .
one week post operation , healing over both the donor and recipient sites was found to be satisfactory , and the sutures were thus removed . to our surprise ,
the patient was kept under regular follow - up for 6 months and , to add to our delight , there were nosigns of graft failure or loco regional recurrence .
intraoperative photograph after complete removal of the tumor the tumor specimen showing the presence of both calcified and epithelial components reconstruction of the mandibular defect was done with iliac crest graft photomicrograph stained with h and e reveals the presence of dense fibrous tissue and a few odontogenic epithelial cell islands .
fibrous tissue is of a primitive type containing spindle - shaped fibroblasts , some areas of hyalinization signifying dentin formation , and some clear spaces of enamel formation .
in addition , odontogenic epithelial cells follicles are visualized with a few stellate cells suggestive of afo
according to the world health organization ( who ) , an afo is a benign epithelial odontogenic tumor with odontogenic mesenchyme .
a few authors suggest the ameloblastic fibroma and the ameloblastic fibrodentinoma as its precursors . a long - standing case of afo may progress to complex odontoma .
it is an asymptomatic , slow - growing tumor mostly associated with an unerupted tooth . in our case
slootweg reviewed 50 cases with this condition , for which the mean age was 8.1 years ( range 1 - 20 years ) .
radiographically , it appears as a well - circumscribed , expansile radiolucency that generally contains solitary or multiple small radiopaque foci .
large areas of calcification make it impossible to differentiate an afo radiographically from a complex odontoma .
differential diagnoses include lesions with mixed radiographic features , such as immature complex odontoma , calcifying epithelial odontogenic tumor , adenomatoid odontogenic tumor , and ameloblastoma .
the relative arrangement of the soft tissues and the stage of development of the involved tooth are useful criteria for diagnosis .
the tumor mass is surrounded by a fibrous capsule and is composed predominantly of a fibroblastic connective tissue matrix containing strands of odontogenic epithelium and immature tooth structures , including enamel and dentin .
an afo is an immature variant of complex odontoma , as the clinical and radiographic findings are identical .
the authors certify that they have obtained all appropriate patient consent forms . in the form the patient(s )
has / have given his / her / their consent for his / her / their images and other clinical information to be reported in the journal .
the patients understand that their names and initials will not be published and due efforts will be made to conceal their identity , but anonymity can not be guaranteed .
the authors certify that they have obtained all appropriate patient consent forms . in the form the patient(s )
has / have given his / her / their consent for his / her / their images and other clinical information to be reported in the journal .
the patients understand that their names and initials will not be published and due efforts will be made to conceal their identity , but anonymity can not be guaranteed .
Output:
| an ameloblastic fibroodontoma ( afo ) is a rare odontogenic tumor of mixed dental tissue origin .
it exhibits histological features of ameloblastic fibroma and complex odontoma .
afos are usually found to be asymptomatic and are most often discovered on routine radiography .
sometimes their presence is suspected due to missing permanent dentition .
we report a case of an 18-year - old female patient with missing mandibular molars on the left side associated with a giant complex odontoma .
treatment included surgical excision of the tumor followed by reconstruction with iliac crest graft .
histopathological study revealed it as an afo , to our surprise . |
PubmedSumm6587 | ***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: previous studies examining the relationship between hospital costs and health outcomes have reached divergent conclusions . whereas some studies have found a positive association between hospital costs and health outcomes ( mukamel , zwanziger , and tomaszewski 2001 ) , others have concluded that low hospital costs and excellent health outcomes are not mutually exclusive ( fleming 1991 ; carey and burgess 1999 ) .
weech - maldonado , shea , and mor ( 2006 ) examined the cost / outcome relationship for nursing homes and found that the pattern of the relationship depended on the choice of outcome measures .
different studies examining the relationship between inefficiency and health outcomes have also yielded contradictory results .
morey et al . ( 1992 ) and deily and mckay ( 2006 ) found that a hospital 's inefficiency score was positively associated with the observed in - hospital mortality rate , whereas mckay and deily ( 2008 ) did not find any consistent association .
some studies have used cost functions with costs as the dependent variable , where outcome measures were explanatory variables in a given cost function ( fleming 1991 ; carey and burgess 1999 ; weech - maldonado , shea , and mor 2006 ) .
this cost function usually has a hybrid functional form following grannemann , brown , and pauly ( 1986 ) .
however , mukamel , zwanziger , and tomaszewski ( 2001 ) , deily and mckay ( 2006 ) , and mckay and deily ( 2008 ) used outcomes as the dependent variables , where hospital cost was one explanatory variable .
a common feature of these studies is their use of aggregate measures for costs and health outcomes .
most studies use mortality ( i.e. , usually in - hospital mortality ) as the only outcome measure ( morey et al .
1992 ; mukamel , zwanziger , and tomaszewski 2001 ; deily and mckay 2006 ; ) . using both readmissions and mortality , fleming ( 1991 ) found that the association with costs was positive at low outcome levels , negative at intermediate outcome levels , and positive again at high outcome levels for both outcomes measures .
however , mckay and deily ( 2008 ) also used readmissions in addition to mortality and found no systematic pattern .
carey and burgess ( 1999 ) used posthospitalization outcomes for mortality and readmission , as well as outpatient follow - up rates .
they found that all three outcome measures were positively associated with hospital costs ( i.e. , high levels of mortality were associated with high costs ) .
weech - maldonado , shea , and mor ( 2006 ) used pressure ulcers and mood decline as outcome measures in nursing homes .
the goal of the present study was to explore and to quantify the relationship between costs and outcomes of treatment for ami while controlling for comorbidity , input quality , and organizational hospital characteristics .
we used individual - level data for costs , outcomes , and comorbidity from the vha .
mortality and readmission , each assessed 1 year after the index hospitalization , were used as measures of clinical outcome .
we hypothesized that outcome would be a function of age , comorbidities , costs , and hospital organizational characteristics .
while age , comorbidities , and costs can differ for each treated patient , hospital organizational characteristics remain identical for all patients treated in a given hospital . as a result , observations across patients violate assumptions such as independence and common variance .
significance tests are thus not robust and would overestimate the precision of information provided by the hospital - level variables . to avoid this problem , we applied random - effects proportional hazard models , also known as frailty models ( yamaguchi et al .
, we took a two - level multilevel modeling approach , nesting treated patients as microunits within hospitals , which were , in turn , considered to be macrounits .
we used the following model : where hij(t ) is the hazard for the ith patient in the jth hospital at time t. h0(t ) is the unspecified baseline hazard .
xij is a vector of explanatory variables at the patient level , while zj is a vector of explanatory variables at the hospital level .
and are two vectors that measure the effects of xij and zj , respectively .
0j , or 0j ( = exp(0j ) ) , if interpreted as a factor , represent the deviation of hospital j from the overall baseline hazard .
two models were estimated , one model for time to death and one model for time to readmission .
as the event death is a competing risk for the event readmission , that is , death at a specific point in time thereafter excludes readmission , we treated observations that died as censored at the time of death in the readmission model ( allison 2005 ; s , dismuke , and guimaras 2007 ; ) .
however , is not a competing risk for the event death because the data allowed a follow - up for 365 days after index admission .
we also assumed that costs were endogenous to health outcomes , which we confirmed using the hausman test ( hausman 1978 ) .
thus , we subsequently used two - stage residual inclusion ( 2sri ) based on terza , basu , and rathouz ( 2008 ) .
the two - stage approach is less efficient than full information maximum likelihood but yields consistent estimates .
2sri has been used before for survival outcomes in a health care context by lindrooth and weisbrod ( 2007 ) .
the method requires the use of instrumental variables , that is , variables that are highly correlated with the endogenous variable ( costs ) , but not with unobserved determinants of the main outcome variable of interest ( time to readmission conditional on not dying , time to death ) .
these assumptions are often satisfied by variables that are correlated with the endogenous variable but have no direct effect on the outcome variable ( cameron and trivedi 2005 ) .
we believe that the medicare wage index and general overhead costs per day at the hospital level meet these criteria .
the medicare wage index adjusts hospital costs for regional differences in medical wages across the united states .
one could argue that higher wages may represent an extrinsic incentive for staff to perform better and deliver higher quality care .
however , the medicare wage index only covers wage differences between , and not within , regions and thus is unlikely to have a direct effect on health outcomes .
general overhead costs per day at the hospital level include cost elements from the nonmedical infrastructure of a hospital , for example , costs for activities such as housekeeping , engineering , and administration .
note that we excluded medical department overhead from overhead costs . the variable general overhead costs per day thus acts as a proxy for the price level a hospital faces to purchase certain activities excluding prices for medical personnel .
the costs are allocated by charging the same amount for each patient day irrespective of the reason for admission .
thus , this is a specific type of overhead costs , which does not relate to the actual hospital stay of each patient .
these overhead costs are predominantly fixed in the short term and are not related to ami treatment and severity of disease .
it should also be pointed out that this type of overhead costs is not related to either hospital size or angiography , because we control for both of these in the analysis at both stages of the estimation .
given our definition of general overhead costs per day at the hospital level , the variable is highly correlated with individual level costs per case but is unlikely to be associated with health outcomes .
in particular we also included the hospital 's occupancy rate and the overall hospital 's case mix .
however , their explanatory power was calculated to be low ( i.e. , with an f - value < 10 ) . because the use of weak instruments can be problematic in statistical analysis
we first estimated a generalized linear mixed model with cost as the dependent variable and all variables at the patient and hospital levels , including the medicare wage index and general overhead costs per day at the hospital level , as explanatory variables .
we assumed a gamma distribution for the variable cost and used a log - link function .
the functional form of the cost function incorporates variables used in structural cost functions and variables on an ad hoc basis ( grannemann , brown , and pauly 1986 ) .
subsequently , we estimated two separate random - effects proportional hazard models for mortality and readmission using the survival package of the statistical program r , which allows for frailty models .
actual costs and residuals from the first - stage regression were used in the second stage ( terza , basu , and rathouz 2008 ) .
we also reestimated including polynomials of the residuals . to adjust standard errors of the second - stage regression for including estimated residuals from the first stage , murphy
topel adjustment was used ( murphy and topel 1985 ) . to assess the validity of the proportional hazards assumption , we plotted scaled schoenfeld residuals against event time .
in addition , according to a test suggested by grambsch and therneau ( 1994 ) , we regressed scaled schoenfeld residuals on event time for each covariate and tested for zero slope .
the goal of the present study was to explore and to quantify the relationship between costs and outcomes of treatment for ami while controlling for comorbidity , input quality , and organizational hospital characteristics .
we used individual - level data for costs , outcomes , and comorbidity from the vha .
mortality and readmission , each assessed 1 year after the index hospitalization , were used as measures of clinical outcome .
we hypothesized that outcome would be a function of age , comorbidities , costs , and hospital organizational characteristics .
while age , comorbidities , and costs can differ for each treated patient , hospital organizational characteristics remain identical for all patients treated in a given hospital . as a result , observations across patients violate assumptions such as independence and common variance .
significance tests are thus not robust and would overestimate the precision of information provided by the hospital - level variables . to avoid this problem , we applied random - effects proportional hazard models , also known as frailty models ( yamaguchi et al .
, we took a two - level multilevel modeling approach , nesting treated patients as microunits within hospitals , which were , in turn , considered to be macrounits .
we used the following model : where hij(t ) is the hazard for the ith patient in the jth hospital at time t. h0(t ) is the unspecified baseline hazard .
xij is a vector of explanatory variables at the patient level , while zj is a vector of explanatory variables at the hospital level .
and are two vectors that measure the effects of xij and zj , respectively .
0j , or 0j ( = exp(0j ) ) , if interpreted as a factor , represent the deviation of hospital j from the overall baseline hazard .
two models were estimated , one model for time to death and one model for time to readmission .
as the event death is a competing risk for the event readmission , that is , death at a specific point in time thereafter excludes readmission , we treated observations that died as censored at the time of death in the readmission model ( allison 2005 ; s , dismuke , and guimaras 2007 ; ) .
however , is not a competing risk for the event death because the data allowed a follow - up for 365 days after index admission .
we also assumed that costs were endogenous to health outcomes , which we confirmed using the hausman test ( hausman 1978 ) .
thus , we subsequently used two - stage residual inclusion ( 2sri ) based on terza , basu , and rathouz ( 2008 ) .
the two - stage approach is less efficient than full information maximum likelihood but yields consistent estimates .
2sri has been used before for survival outcomes in a health care context by lindrooth and weisbrod ( 2007 ) .
the method requires the use of instrumental variables , that is , variables that are highly correlated with the endogenous variable ( costs ) , but not with unobserved determinants of the main outcome variable of interest ( time to readmission conditional on not dying , time to death ) .
these assumptions are often satisfied by variables that are correlated with the endogenous variable but have no direct effect on the outcome variable ( cameron and trivedi 2005 ) .
we believe that the medicare wage index and general overhead costs per day at the hospital level meet these criteria .
the medicare wage index adjusts hospital costs for regional differences in medical wages across the united states .
one could argue that higher wages may represent an extrinsic incentive for staff to perform better and deliver higher quality care .
however , the medicare wage index only covers wage differences between , and not within , regions and thus is unlikely to have a direct effect on health outcomes .
general overhead costs per day at the hospital level include cost elements from the nonmedical infrastructure of a hospital , for example , costs for activities such as housekeeping , engineering , and administration .
note that we excluded medical department overhead from overhead costs . the variable general overhead costs per day thus acts as a proxy for the price level a hospital faces to purchase certain activities excluding prices for medical personnel .
the costs are allocated by charging the same amount for each patient day irrespective of the reason for admission .
thus , this is a specific type of overhead costs , which does not relate to the actual hospital stay of each patient .
these overhead costs are predominantly fixed in the short term and are not related to ami treatment and severity of disease .
it should also be pointed out that this type of overhead costs is not related to either hospital size or angiography , because we control for both of these in the analysis at both stages of the estimation .
given our definition of general overhead costs per day at the hospital level , the variable is highly correlated with individual level costs per case but is unlikely to be associated with health outcomes .
in particular we also included the hospital 's occupancy rate and the overall hospital 's case mix .
however , their explanatory power was calculated to be low ( i.e. , with an f - value < 10 ) . because the use of weak instruments can be problematic in statistical analysis
we first estimated a generalized linear mixed model with cost as the dependent variable and all variables at the patient and hospital levels , including the medicare wage index and general overhead costs per day at the hospital level , as explanatory variables .
we assumed a gamma distribution for the variable cost and used a log - link function .
the functional form of the cost function incorporates variables used in structural cost functions and variables on an ad hoc basis ( grannemann , brown , and pauly 1986 ) .
subsequently , we estimated two separate random - effects proportional hazard models for mortality and readmission using the survival package of the statistical program r , which allows for frailty models .
actual costs and residuals from the first - stage regression were used in the second stage ( terza , basu , and rathouz 2008 ) .
we also reestimated including polynomials of the residuals . to adjust standard errors of the second - stage regression for including estimated residuals from the first stage , murphy
topel adjustment was used ( murphy and topel 1985 ) . to assess the validity of the proportional hazards assumption , we plotted scaled schoenfeld residuals against event time .
in addition , according to a test suggested by grambsch and therneau ( 1994 ) , we regressed scaled schoenfeld residuals on event time for each covariate and tested for zero slope .
the primary data source in this study was a set of vha administrative files for the fiscal years 2000 through 2006 . for each ami patient , we selected the index hospitalization during which a primary diagnosis of ami was made .
we excluded all patients who were admitted and discharged on the same day , because we assumed that these patients were transferred to other hospitals or ruled out for ami .
moreover , we excluded patients who had been admitted with ami in the previous year , as well as those whose ami was coded as an in - hospital complication . ultimately , a total of 115 vha hospitals with 35,279 patients remained in the sample . for measuring costs , the vha database offers several advantages over the american hospital association data commonly used in u.s .
hospital cost estimation , because the former is based on the requirement that hospitals provide information to a standardized internal accounting system that is subject to extensive periodic audits .
the vha accounting system was established in the 1990s and has been continuously improved since then .
it provides detailed cost information for hospitalization episodes and thus individual - level cost data .
moreover , it includes the costs of physicians while , at the same time , excluding capital costs .
we eliminated the costs of postacute care , a component usually included in vha hospital costs , from the total costs , and we excluded patients whose total treatment costs were recorded as being < u.s.$100 , interpreting this as an obvious accounting error .
finally , costs were deflated to reflect year 1999 values . to control for patient comorbidities , we compiled a comprehensive list of comorbidities that have been found in other studies to affect mortality .
in doing so , we relied on the ontario acute myocardial infarction mortality prediction rules ( tu et al .
2001 ) and the charlson comorbidity index ( sundararajan et al . 2004 ) . because evans et al .
( 2007 ) have shown that comorbidities associated with mortality in ami patients are also associated with resource use , we hypothesized that these and other predictors of mortality risk would also be associated with inpatient costs .
we thus also included the full set of comorbidities for the first - stage cost estimation . for coding diagnoses
we obtained data on hospital organizational characteristics that we judged to be potentially associated with outcomes .
the number of treated ami patients per hospital was included to control for volume effects , because a larger number of treated cases has been found to be associated with superior outcomes for specific indications ( birkmeyer et al .
, we used the number of beds to control for the size of the hospital ( carey and burgess 1999 ; dudley et al .
one of these was a dummy variable for a hospital 's teaching status , which we used as a proxy for staff qualification and equipment .
each vha hospital was classified as a teaching - affiliated hospital if it was a member of the council of teaching hospitals ( coth ) . as a proxy for labor intensity
, we included the ratio of nurses per bed for each hospital ( needleman et al .
( 2004 ) , we also included a dummy variable for a hospital 's capability to perform coronary angiography ; we counted five or more claims for coronary angiography as evidence of a hospital 's capability to perform this procedure .
all hospital characteristics were also included in the first - stage cost equation . to control for regional effects
, we included regional dummies into first- and second - stage equations . as discussed previously , we estimated a cost equation in the first stage .
the additional variables included in this equation are the medicare wage index obtained from the centers for medicare and medicaid services and general overhead costs per day on hospital level .
table 2 presents coefficient estimates and p - values for the first - stage cost equation .
the signs of the estimated coefficients were generally in line with our expectations , and the variables for medicare wage index and general overhead costs per day were highly significant .
characteristics of the study sample values for mortality do not include cases who died during index hospitalization .
the coefficients for ami cases ( no . ) and beds were multiplied by 100 .
table 3 shows the results of the second - stage regression models , with mortality and readmission conditional on not dying as dependent variables . for the mortality equation ,
the majority of coefficients had the expected signs and the equation showed a highly significant negative association between costs and mortality .
every u.s.$100 less spent is associated with a 0.63 percent increase in the hazard of dying .
the risk for mortality also decreased significantly as the number of treated ami cases per hospital increased ( each additional ami case treated decreased the hazard of dying by 0.32 percent ) .
every u.s.$100 less spent is associated with a 1.24 percent increase in the hazard to be readmitted conditional on not dying . except for angiographic capability that was positively associated with readmission conditional on not dying , hospital - level variables were not significant .
dependent variables : time to death and time to readmission within 1 year of discharge .
the coefficients for ami cases ( no . ) and beds were multiplied by 100 .
we tested the robustness of our findings in five ways . to begin with , we reestimated the first- and second - stage regressions using readmission and mortality assessed 1 year after admission from the index hospitalization instead of discharge .
thus , in these reestimated models mortality and readmission are dated from the admission to the hospital because one could argue that if dated from discharge some individuals would be observed shorter than others due to longer hospitalization .
second , we ran the models by excluding cases that were transferred between different hospitals during index hospitalization ( 3,131 cases ) .
the modification had very little impact on the coefficient of the cost variable , which remained highly significant in both equations .
third , we reestimated both models without a multilevel approach dropping the higher level variables . in doing so
, we made a correction for clusters of the variance covariance matrix to obtain a robust estimate in the second stage .
the size of the coefficients decreased slightly in both equations , but it remained highly significant .
fourth , we ran the models with an extended observation period of 2 years instead of 1 year for both outcomes .
again the modification had very little impact on the coefficient of the cost variable , which remained highly significant in both equations .
fifth , we obtained f - statistics to test the reliability of our instrument ( i.e. , whether our instrument was correlated with the costs ) . because the f
- statistics for the medicare wage index and general overhead per day were 23.69 and 58.91 , respectively , weak correlation is unlikely to be a source of bias ( bound , jaeger , and baker 1995 ; staiger and stock 1994 ) .
when plotting scaled schoenfeld residuals against event time for the survival models , the mortality model appeared to be a good fit to the data .
according to the regressions , the proportional assumption seems to have been violated for the variable chronic renal failure , and some of the dummy variables for year of treatment .
however , this might also be due to the ols regression being heavily influenced by outliers ( thompson et al .
2003 ) that could be identified in the plots . in the readmission model , however , the proportional hazard assumption seems to have been violated more often .
therefore , and as an additional sensitivity analysis , we also fitted a weibull model for mortality and readmission , respectively .
the results in both models , that is , the sign of the coefficient for the variable cost and the p - value , remained robust .
if parameter estimates of the weibull models are transformed to hazard ratios , every u.s.$100 less spent is associated with a 0.64 percent increase in the hazard of dying and a 1.27 percent increase in the hazard of a readmission conditional on not dying .
in this paper , we investigated and we quantified the relationship between hospital costs and health outcomes for patients with ami using a two - step random intercept cox proportional hazard model to obtain consistent estimates of the effects of costs on outcomes .
we followed a more refined approach than previous studies investigating this relationship by ( a ) focusing on one episode of care , ( b ) using patient - level data , and ( c ) applying a survival model .
we found that costs were negatively associated with mortality and with readmission conditional on not dying .
outcome relationship appears to be very clear in both cases , although costs were more significant in the readmission equation compared with the mortality equation .
the finding that the relationship between costs and outcomes is negatively correlated for both outcome measures is at odds with the results obtained by carey and burgess ( 1999 ) , who also based their analysis on vha data .
they found that both 1-year mortality and 1-year readmissions were positively associated with hospital costs .
they suggested that differences in severity of illness unmeasured by the case mix were a likely explanation for this result .
however , comparability to our study is limited by the fact that carey and burgess ( 1999 ) did not concentrate solely on ami as one episode of care and by that they used aggregate hospital costs instead of patient - level costs .
in addition , they did not use a survival model and did not control for competing risks . in general , none of the previous studies used a survival model to investigate the cost outcome relationship , making any comparison with our study difficult .
the negative association between costs and the risk for mortality / readmission conditional on not dying confirms the often - stated hypothesis that increased resource input for patients should clearly lead to better outcomes .
some of the hospital - level variables had unexpected signs , although most of them ( e.g. , coth ) were not significant .
however , the positive coefficient for the variable for capability of angiography in both equations suggests that the risk for an event , that is , readmission conditional on not dying or death , increases significantly with capability of angiography .
one potential explanation for this pattern may be that certain measures for case mix are not included .
thus , the positive coefficients for angiography capability may reflect higher severity rather than input quality .
, it is the first study , to our knowledge , to examine the trade - off between costs and outcomes using patient - level cost and outcome data .
the use of patient - level data enabled us to obtain more consistent estimates on the relationship between costs and outcomes .
second , we focused on ami as one episode of care , which allowed us to control appropriately for case mix .
third , we are the first study exploring this trade - off using a cox proportional hazard model and considering the competing risk nature of the data .
fourth , the rich data sample containing information at the patient and hospital levels allowed us to use a multilevel model combined with a 2sri model .
first , certain undocumented health - related conditions or factors may explain part of the variation in our outcome variables , thus potentially affecting the relationship between costs and outcomes . also , the validity of the instruments relies on the assumption that the error structure follows a random effects model
. another limitation may be this study 's focus on mortality and readmissions as opposed to clinical - outcome measures .
although the vha has a standardized internal accounting system , certain variations in costs may be explained by the different accounting systems used in different vha hospitals , which is a factor we were unable to control for .
finally , our study uses only vha data , which raises the question of generalizability beyond the vha .
it is likely that the relationship between costs and outcomes varies according to the health care context , differing , for example , between fragmented and integrated health care systems .
for instance , an integrated delivery system with managed care elements , such as the vha , is more likely than fragmented health care systems to avoid or substitute readmissions .
thus , in the vha context , it is conceivable that patients with multiple conditions for which acute hospital treatment was not appropriate were less likely to be readmitted . in spite of the clear findings
certainly , the negative association between costs and mortality and costs and readmission conditional on not dying does not mean that every clinical intervention is justified , especially if the costs of the intervention are greater than the benefits .
however , this negative association does suggest that reductions in costs may indeed lead to poorer outcomes .
because of this , outcomes should be monitored closely when introducing cost - containment programs . moreover , linking reimbursement rates to outcomes , as is practiced in reimbursement programs such as pay for performance in the united states or
payment by results in the united kingdom , might represent a promising approach to overcoming the trade - off between costs and outcomes , supplying providers with incentives to keep outcomes stable in spite of decreasing costs .
outcome relationship for conditions other than ami to see whether our results are consistent . with this in mind , examining the various treatment processes within organizations would also seem a fruitful way of gaining a greater understanding of this relationship .
additional supporting information may be found in the online version of this article : appendix sa1 : author matrix .
please note : wiley - blackwell is not responsible for the content or functionality of any supporting materials supplied by the authors .
any queries ( other than missing material ) should be directed to the corresponding author for the article .
Output:
| objectiveto investigate and to quantify the relationship between hospital costs and health outcomes for patients with acute myocardial infarction ( ami ) in veterans health administration ( vha ) hospitals using individual - level data for costs and outcomes.data sourcesvha administrative files for the fiscal years 20002006.study designcosts were defined as costs incurred during the index hospitalization for treatment of ami .
mortality and readmission , assessed 1 year after the index hospitalization , were used as measures of clinical outcome .
we examined health outcomes as a function of costs and other patient - level and hospital - level characteristics using a two - stage cox proportional hazard model that accounted for competing risks within a multilevel framework . to control for patient comorbidities , we compiled a comprehensive list of comorbidities that have been found in other studies to affect mortality and readmissions.principal findingswe found that costs were negatively associated with mortality and readmissions .
every u.s.$100 less spent is associated with a 0.63 percent increase in the hazard of dying and a 1.24 percent increase in the hazard to be readmitted conditional on not dying .
this main finding remained unchanged after a number of sensitivity checks.conclusionsour results suggest that there is a trade - off between costs and outcomes .
the negative association between costs and mortality suggests that outcomes should be monitored closely when introducing cost - containment programs .
additional studies are needed to examine the cost
outcome relationship for conditions other than ami to see whether our results are consistent . |
PubmedSumm6588 | ***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: radical prostatectomy is regarded as the gold standard surgical treatment for organ confined prostate cancer . even though the surgical technique has been improved steadily stress urinary
incontinence is a well - known side effect of this procedure with reported incidence rates of up to 20% [ 1 , 2 ] .
another rare reason for postsurgery incontinence is the transurethral resection ( tur ) of the prostate .
the artificial urinary sphincter is still considered to be the standard surgical treatment for stress incontinence after prostate surgery with good long - term results in terms of continence and quality of life [ 4 , 5 ] . however , besides patients ' requirement of mental capacity and fine - motor control to operate the implanted pump , the significant reoperation rate 35% due to well - known complications such as cuff erosion , infection , or mechanical problems lead to an establishment of minimal invasive sling systems for treatment of urinary incontinence in the last years .
the retrourethral transobturator sling suspension ( rts ) , ( advance male sling , american medical systems , minnetonka , mn , usa ) , introduced in 2006 , offers a functional approach by relocating the descent proximal urethra into the original anatomic position and thus allowing adequate function of the sphincter [ 7 , 8 ] .
therefore sufficient sphincter contraction with or without complete closure is essential for the success of this approach .
promising results in recent studies show success rates from 5480% regarding improved continence with few serious complications .
however , failure rates of up to 36.5% and even worsening in 9% have been reported . taking these objections into account
, this study was performed to prospectively evaluate the functional outcome of the rts at our institution .
from september 2010 to september 2011 , 32 patients with mild to severe stress urinary incontinence after prostate surgery were treated with rts in the department of urology , university hospital ulm .
twenty - eight patients ( 87.5% ) had undergone radical prostatectomy for prostate cancer , the remaining 4 patients ( 12.5% ) had been treated with transurethral resection of the prostate .
the median time between prostate surgery to sling implantation was 56 months ( range , 6161 ) .
the implantation of the male sling system was performed at least 6 months after initial treatment .
ten patients ( 31.3% ) were treated with transurethral incision of the bladder neck in case of bladder - neck obstruction prior ( n = 8) to or during ( n = 2 ) the implantation of the rts .
six men ( 18.8% ) had been treated with bulking agents without success before sling implantation .
preoperative work - up included physical examination , uroflowmetry ( qmax ) , postvoid residual urine ( pvr ) and flexible urethroscopy to assess sphincter function and mobility of the membranous urethra .
the repositioning test [ 9 , 13 ] was used to simulate the function of male sling before implantation .
iciq - ui sf 2004 score , a validated self - report questionnaire , was assessed to evaluate urinary incontinence and its impact on quality of life .
degree of incontinence was classified by the number of pads used per 24 hours and categorized in 3 grades ( mild : 1 - 2 , moderate : 35 ; severe : > 5 pads/24 h ) .
table 1 presents patient characteristics before sling implantation in detail . according to a prospective protocol
, patients were reevaluated after 3 , 6 , and 12 months concerning the number of pads used daily , the current iciq - ui sf score , qmax , and pvr .
cure was defined as no pad usage , improvement was defined as a use of 1 - 2 pads / day or 50% reduction of the preoperative pad use .
all complications were recorded and assessed from review of the patients ' clinical record charts .
intraoperative urethroscopy was performed in all cases to validate correct sling placement and to exclude urethral lesions .
chi - square tests were performed to compare the success and failure groups by demographic , clinical , surgical , and follow - up parameters .
the median followup was 9 months ( range , 314 ) . based on pad test results at
last followup the cure rate ( no pad usage ) was 56.3% ( 18 of 32 patients ) .
the improvement rate ( 1 - 2 pads / day or 50% reduction ) was 21.9% ( 7 patients ) .
the success rate was durable since only one patient initially classified as cured at the 3-month visit subsequently had to use pads again in the course of followup .
patients with severe sui ( n = 8) showed a trend of inferior cure rates compared to patients with mild ( n = 6 ) and moderate ( n = 18 ) sui ; however , this was not significant ( 25% versus 83.3% and 61.1% , p = 0.075 , fisher 's exact test ) ( see table 2 ) .
overall mean sd pad use decreased from 5.1 2.8 ( median : 4 , range : 210 ) to 1.8 2.7 ( median : 0 , range : 010 ) pads daily ( p < 0.001 , u test ) .
the iciq - ui sf score improved from a mean of 15.4 3.5 ( median : 16 , range : 721 ) before sling implantation to 5.7 6.3 ( median : 4 , range : 018 ) after surgery ( p < 0.001 ; u test ) ( see table 3 ) .
twenty - one patients ( 65.2% ) demonstrated a 50% reduction or more of the iciq - ui sf score after sling implantation .
the 50% decrease of daily pad use was significantly associated with the 50% decrease of iciq - iu sf score indicating a strong correlation between both parameters ( p < 0.001 , fisher 's exact test ) . to evaluate the potential impact of prior treatment on the sphincter region and thus success of the rts implantation several subgroup analysis was performed .
patients with prior pelvic radiotherapy ( n = 10 , 31.3% ) demonstrated a cure rate of 30% ( n = 3/10 ) and an improvement rate of 30%
the failure rate in patients with prior radiotherapy was 40% ( n = 4/10 ) .
the iciq - ui sf score was decreased by 50% in 40% of these patients .
however , there was no statistical difference regarding pad use and iciq - ui sf score compared to patients without prior radiotherapy ( 50% pad reduction 60.0% versus 81.8% , p = 0.218 and 50% iciq - ui sf score decrease .
44.4% versus 77.3% p = 0.105 , respectively ; without prior radiotherapy 's exact test ) . considering patients with previous or simultaneous transurethral incision of the bladder neck ( n = 10 , 31.3% ) the cure rate was 30% , the improvement rate 20% , and the failure rate 50% . again
, there was a trend towards worse outcome regarding decrease of daily pad use compared to patients without transurethral incision ( 50% ; 50.0% versus 86.8% ; p = 0.072 , fisher 's exact test ) .
however , the reduction of iciq - ui sf score demonstrated a significantly worse outcome in these patients ( 50% ; 33.3% versus 81.8% ; p = 0.015 , fisher 's exact test ) .
neither pretreatment with bulking agents nor patient age ( 70 yrs . versus < 70 yrs . ) had impact on improvement of pad use or iciq - ui sf score after sling implantation .
no changes in postvoid residual urine ( pvr ) were observed after the implantation of the rts ( mean : 7.3 12.8 ml versus 11.0 19.0 ml ; p = 0.381 , u test ) .
uroflowmetry demonstrated significant decreased qmax rates ( mean : 20.3 11.9 versus 23.9 13.6 ml / sec ) after sling implantation ( p < 0.001 , u test ) .
no perioperative serious complications occurred . in one patient the rts had to be removed because of sling dislocation and persistent perineal pain .
the patient had undergone prior pelvic radiotherapy and palliative transurethral laser resection before sling implantation .
postoperative acute urinary retention ( aur ) was seen in five patients ( 15.6% ) .
the catheter could be removed after 13 weeks without further treatment with residual urine 50 ml at time of catheter removal .
3 patients ( 9.3% ) had mild local wound infection / inflammation and were treated conservatively with oral antibiotics .
midterm outcome in a recent study showed sustainable results over a followup period of up to two years .
most common complications of the male sling are urinary retention , impaired healing , and sling dislocation due to inflammation or misplacement [ 13 , 19 ] . in our present study
considering these data , implantation of rts is a valid procedure for treatment of postprostate - surgery incontinence .
the significant decrease of the iciq - ui sf score from a median of 15.4 before sling implantation to 5.7 after surgery underscores this observation .
most common complications were acute urinary retention in 15.6% and wound healing disorders in 9.3% .
one patient underwent sling removal because of dislocation of the sling system and persistent perineal pain . while acute urinary retention was a transient postoperative observation , mild reduction of qmax was a common finding after male sling implantation in our study suggesting that the implantation and function of the rts result at least partly in obstruction .
in contrast to our observation urodynamic evaluation performed in previous studies had not revealed significant changes of maximum flow rates following sling implantation [ 15 , 16 ] .
however , in the present study the clinical impact of the reduced qmax could almost be disregarded .
residual urine volume demonstrated no significant change after sling implantation and urinary frequency seemed to be unaffected .
most accurate means of predicting treatment success and subsequent selection of appropriate patients for functional transobturator sling implantation are still under debate . in the present study severity of incontinence showed a trend to negative impact on the cure rate .
this observation was found to be significant in a few studies [ 10 , 11 , 20 , 21 ] , whereas no correlation was found in other reports [ 9 , 12 ] .
even though the cure rate was only 25% in patients with severe sui , the present success rate ( cure rate + improvement rate ) of 62.5% in this challenging cohort demonstrates that patients with severe incontinence can benefit from sling implantation .
nevertheless , precise patient information about the decreased cure rate is needed if male sling implantation is the chosen treatment in these patients .
although our results are hampered by the small number of cases , analysis of patients with history of radiation therapy showed a tendency of worse outcome in terms of pad use and iciq - ui sf score , respectively .
this observation is in line with cornu et al . who noticed in patients with prior radiotherapy ( n = 17 ) a success rate of 59% ( 9 cured , 1 improved ) compared to 85% in patients without history of pelvic radiation indicating that prior radiation could predict inferior clinical outcome .
in a prospective study bauer et al . reported similar results with a success rate of 50% ( 25% cure rate , 25% improvement rate ) in selected patients ( n = 24 ) after radical prostatectomy and adjuvant radiotherapy .
one explanation for the worse outcome in these patients might be a direct radiogenic damage of the intrinsic sphincter in combination with an increasing immobility of the urethra caused by the irradiated tissue in the perineal area .
moreover , patients with previous or simultaneous anastomotic stricture surgery ( n = 10 ) showed a trend towards inferior outcome regarding decrease of daily pad use compared to patients without history of urethral surgery ( 50.0% versus 86.8% ) .
additionally , the iciq - ui sf score demonstrated a significant worse outcome in these patients ( 50% reduction ; 33.3% versus 81.8% ) .
this corresponds to midterm results reported by cornu et al . on a subgroup of 18 patients with a history of surgery for urethral stenosis demonstrating a significant association with persistent pad use after sling implantation
the lower success rate in patients with prior transurethral surgery may be caused by the immobility of a
our study indicates that prior therapy with potentially negative impact on the urethral mobility has a negative influence on treatment success .
therefore , in this challenging cohort we recommend using the functional treatment approach of the rts very cautiously .
the limitation of our study is certainly the low number of patients with a mean followup of 9 months after implantation .
long - term prospective studies with focus on risk factors of treatment failure after rts implantation are warranted to prove real value .
the retrourethral transobturator male sling represents a safe and effective treatment option for patients with postprostate - surgery sui .
history of radiotherapy and urethral surgery as well as severe incontinence should be carefully considered in the preoperative selection of patients since in this subgroup the success rate of advance male sling implantation could be lower .
Output:
| objective . to evaluate functional outcome of the retrourethral transobturator sling suspension ( rts ) in the treatment of stress urinary incontinence ( sui ) caused by prior prostate surgery
. methods .
the rts ( advance male sling ) was implanted in 32 patients who suffered from mild to severe postsurgical - treatment incontinence at the university hospital ulm from september 2010 to september 2011 including 10 patients with prior radiation therapy .
functional data ( uroflowmetry , daily pad use , and postvoid residual urine ) as well as quality of life with impact of urinary problems ( iciq - ui sf ) were prospectively assessed at baseline and during followup .
results . after a median followup of 9 months ( range , 314 )
the incontinence cure rate ( no pad usage ) was 56.2% and the improvement rate ( 1 - 2 pads / day or 50% reduction ) was 21.9% .
no improvement was observed in 21.9% .
daily pad use and iciq - ui sf score improved significantly .
no major perioperative complications occurred .
postoperatively , 15.6% of the patients exhibited transient acute urinary retention which resolved without further treatment after a maximum of 3 weeks .
one patient underwent sling explantation due to dislocation and persistent perineal pain .
conclusions .
the implantation of the rts is a safe and effective procedure in selected patients with sui resulting from prostate surgery . |
PubmedSumm6589 | ***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: spontaneous intramedullary hemorrhage is a rare disease entity , and most cases have specific etiologies , such as vascular malformations and tumorous lesions61112 ) .
there are also reports indicating that anticoagulation therapy and hemophilia cause spontaneous intramedullary hemorrhage1313 ) .
it is extremely rare for this to occur without an apparent underlying etiology , and only a few such cases have been reported468910 ) .
recurrent hemorrhage is thought to be the cause of progressive and stepwise neurological deterioration in vascular malformations of the spinal cord2 ) , and a high risk of rebleeding from a vascular malformation is the reason why total excision of the pathology is important .
although there have been some reports suggesting the occurrence of recurrent bleeding in chronic forms of intramedullary hemorrhage without apparent etiology710 ) , it is extremely rare for recurrent intramedullary hemorrhage to occur acutely without a specific cause . here ,
while we describe this rare event , we discuss its etiology , and the diagnostic , therapeutic and prognostic implications of this disease including a review of the relevant literature .
a 48-year - old woman visited our emergency department complaining of voiding difficulty , weakness and sensory disturbances in both lower extremities , which had started 7 days ago prior to her visit .
an initial neurological examination revealed grade iii motor power for the right and grade iv motor power for left lower extremity , and she was unable to walk .
she had been taking an antihypertensive medication for 4 years . otherwise she had no known diseases such as blood dyscrasias , bleeding disorders , cardiovascular disorders , and various other central nervous system disorders .
thoraco - lumbar spine magnetic resonance imaging ( mri ) revealed an intramedullary mass lesion at the t9 - 10 level , which showed as a high signal in a t1 weighted image ( fig .
following gadolinium injection , subtle enhancement at the periphery of the mass was observed ( fig .
midline myelotomy along the dorsal columns was performed , and a dark - colored hematoma was evacuated .
it was mostly liquefied , but some of it was not . keeping cavernous malformation in mind as a possible diagnosis , the dark blood clots were carefully dissected from the spinal cord and sent for histopathological examination . on careful inspection of the intraspinal cavity , neither abnormal vessels nor tumorous lesions
postoperative mri revealed most of the lesion was removed , and no abnormal findings other than postoperative changes were observed ( fig .
an mri was immediately taken , and it showed an increased extent of intramedullary hemorrhage at the operation site ( fig .
laboratory examination revealed no abnormality of coagulation profile ( prothrombin time international normalized ratio , 0.99 ( reference 0.85 - 1.3 ) , activated partial thromboplastin time , 30.7 seconds ( reference 30 - 47 seconds ) ) .
however , we failed to identify any abnormal vasculature or tumorous lesion that might have caused rebleeding .
lesions which might have caused the recurrent bleeding were dissected and biopsied for pathologic diagnosis . during the operation ,
the spinal cord was so severely swollen that we had to perform expansile duroplasty using artificial dura .
the pathology report again confirmed only hematoma , and no abnormal vessels or atypical cells were identified .
a mri that was taken seven days after the second surgery showed a markedly decreased extent of the intramedullary hemorrhage and a spinal cord herniation to the dorsal side , which was due to the expansile duroplasty .
. a rehabilitation program was arranged , and motor power in both of her lower extremities gradually improved .
three months after surgery , motor power in both right and left legs were improved to grade 2 and 3 , respectively . at a 9-month follow - up
in addition , self - voiding became possible with a maneuver to increase abdominal pressure .
what makes this case unique from others is that two confirmed events of intramedullary hemorrhage without specific cause occurred , and that the second event happened a few days after the surgery to perform hematoma evacuation with meticulous bleeding control .
evidence for recurrent bleeding in chronic forms of spontaneous intramedullary hemorrhage are present in the literature10 ) , but it was difficult to find a case similar to the present one .
variable causes of intramedullary hemorrhage , such as vascular malformations , tumorous conditions , and conditions causing coagulopathies and trauma have been proposed4 ) .
although it is extremely rare , there are a few reports of cases of intramedullary hemorrhage without an identifiable etiology .
the stages and extent of hematoma can be seen clearly , and sometimes the underlying pathology can be identified .
the hematoma usually compresses the surrounding neural tissue and the possibility that small obliterated lesions are present that do not appear on a mri scan should be considered . in the present case ,
the periphery of the hematoma was likely to enhance , and our preoperative diagnosis was intramedullary ependymoma with hemorrhage .
however , intraoperative inspection and the pathology report did not find any pathology that might cause hemorrhage .
five days after the initial surgery , rebleeding at the operation site occurred . because it was possible that the etiology had been missed during the first surgery , possible lesions that might cause the recurrent bleeding were dissected and biopsied during the second surgery .
again , no abnormal lesions other than hematoma were confirmed in the final pathology report .
postoperative mris taken after the first and second operations also showed no abnormal enhancement of vessels or mass lesions , except for normal postoperative changes . with these findings , we concluded that the diagnosis of our case was spontaneous idiopathic intramedullary hemorrhage .
some authors disagree with its use if a mri did not show any abnormal vessels56 ) .
idiopathic intramedullary hemorrhage is usually diagnosed by surgery when no underlying pathology is found in macro- and microscopy4 ) .
however , most recurrent hemorrhage cases in central nervous system have a vascular pathology with a bleeding focus , and it is logical to think so in our case . in this context , spinal angiography would have been helpful to identify the etiology of recurrent bleeding , and we think that it was necessary to do the angiography on looking back upon this case .
most of the literature recommends early diagnosis and surgery for cases of intramedullary hemorrhage with progressive neurologic deterioration4569 ) .
in addition , our case suggests that delayed hemorrhage can occur without the presence of an etiology even after meticulous bleeding control is performed in a previous surgery .
approximately 9 months later , motor power in both legs improved and the patient could walk a short distance with the aid of a walker .
we emphasize that surgical intervention should be performed as soon as possible to preserve and restore neurological functions in cases of idiopathic spontaneous intramedullary hemorrhage .
because spontaneous intramedullary hemorrhage with unknown etiology is very rare , meticulous inspection of the hemorrhagic site to find the cause is essential .
repeated hemorrhage can occur ; close observation of patients after surgery is therefore important in cases without an apparent etiology .
Output:
| a 48-year - old woman presented with acute voiding difficulty , numbness and weakness of both lower extremities . magnetic resonance imaging ( mri ) showed an intramedullary hemorrhagic mass that extended from t9 to t10 .
t8-t10 laminotomy and surgical removal of the hemorrhagic mass was performed .
the pathological diagnosis was hematoma .
her neurological status remained the same after the operation . at 5 days post - operation ,
the patient suddenly became paraplegic , and mri that was immediately performed revealed a recurrent intramedullary hemorrhage .
emergent surgical evacuation was performed .
again , histological examination showed only hematoma , without any evidence of abnormal vessels or a tumor .
a postoperative mri revealed no abnormal lesions other than those resulting from postoperative changes . at a 9-month follow up ,
the patient could walk a short distance with the aid of a walker . because spontaneous intramedullary hemorrhage with unknown etiology is very rare
, it is essential to perform a meticulous inspection of the hemorrhagic site to find the underlying cause .
repeated hemorrhage can occur ; therefore , close observation of patients after surgery is important in cases without an apparent etiology .
urgent surgical evacuation is important to improve outcomes in these cases . |
PubmedSumm6590 | ***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: treatment for acute mesenteric ischemia ( ami ) traditionally involves exploratory laparotomy to assess bowel viability and revascularization of visceral arteries , usually the superior mesenteric artery ( sma ) .
revascularization can be achieved through a bypass from the aorta or iliac arteries , embolectomy , open exposure of sma and retrograde recanalization and stent , or percutaneous antegrade stenting via a femoral or brachial approach . in patients without clinical evidence of acute bowel ischemia
flush occlusion of the sma , however , can make antegrade recanalization very challenging and is usually unsuccessful .
transcollateral recanalization of occluded vessels has been previously described for lower extremity disease with good outcomes .
urasawa et al have described retrograde recanalization of superficial femoral artery using profunda femoris collaterals , whereas successful transcollateral recanalization of chronically occluded tibial arteries has also been demonstrated .
there have been a few reports of totally endovascular transcollateral recanalization of sma in cases of chronic mesenteric ischemia and also open laparotomy with retrograde sma stenting ; however , totally endovascular retrograde transcollateral recanalization of sma via the celiac artery ( ca ) has not been described in ami .
we report a case of ami with flush occlusion of the sma and hostile abdomen , who underwent totally endovascular retrograde recanalization of the sma via the ca through the gastroduodenal artery ( gda ) and pancreaticoduodenal arcade .
a 69-year lady with a past medical history of hypertension , hyperlipidemia had 4 months prior presented with acute onset of diffuse abdominal pain with peritonitis , and an elevated lactate and white blood cell ( wbc ) count .
we performed an exploratory laparotomy , sma exploration with direct repair of dissection flap and thrombectomy , bovine pericardium patch angioplasty , and extensive small bowel resection .
her bowel was ultimately put in continuity with 160 cm length of small bowel left .
an angiogram was performed before discharge which showed no flow limiting stenosis in the proximal sma .
she was discharged to rehab where she was recovering with anticoagulation therapy using warfarin which was started for the sma dissection .
she now presented with severe abdominal pain , nausea , vomiting , and diarrhea of 4 h duration .
computed tomographic scan of the abdomen without contrast at an outside hospital showed small bowel with wall thickening .
she was subsequently transferred to our hospital . on examination , her abdomen was tender and she had a wbc count of 20,000 .
there were no obvious peritoneal signs . despite a lengthy conversation , she refused to consent for an open exploratory laparotomy to allow for examination of the bowel . further bowel resection ,
if needed , would have made her dependent on total parenteral nutrition , and she preferred palliative care over laparotomy and possible bowel resection .
she would only consent to a less invasive procedure and thus , we decided to attempt endovascular recanalization of the sma . in the operating room ,
the left brachial artery was used for access due to the steep angulation of the sma .
the descending thoracic aorta was selected and abdominal aortogram obtained using a 5-fr pigtail catheter ( merit medical systems , south jordan , ut ) .
we then selected the ca and then the gda using an advantage glidewire ( terumo , tokyo , japan ) and 5-fr multipurpose catheter ( cordis , miami lakes , fl ) .
selective angiogram ( figure 1 ) revealed the pancreaticoduodenal arcade with filling of the sma . using choice pt ( boston scientific , heredia , costa rica ) and traverse ( abbott vascular , santa clara , ca ) 0.014 wires and progreat ( terumo , tokyo , japan ) microcatheter ,
the sma was selected and crossed , thus entering the aorta ( figure 2 ) .
recanalization of sma through celiac artery with microcatheter and 0.014 wire through the multipurpose catheter .
the traverse wire was then snared using an amplatz gooseneck snare ( ev3 , plymouth , mn ) and brought out through the 7-fr sheath . a left brachial artery
the snare catheter was then advanced into the sma and selective sma angiogram taken ( figure 3a ) revealing a short segment lesion at the origin of the sma without any flow limiting lesion distally .
a 6 38 mm icast ( atrium medical , hudson , nh ) balloon - expandable covered stent was then deployed at the sma origin and then postdilated using a 7-mm balloon .
completion angiogram showed widely open sma with normal filling of its branches ( figure 3b ) . given patient 's inr was > 2 , the brachial sheaths were sutured in place and removed in a few hours after inr reversal by holding manual pressure .
the abdominal pain and wbc count improved within a few days and the patient was successfully discharged back to rehab on general diet .
( a ) antegrade catheterization of sma over the celiac through - and - through wire with pre - sma intervention angiogram .
three and 6-month follow - ups in clinic revealed patient to be doing well and gaining weight .
most cases of ami undergo exploratory laparotomy with concomitant visceral artery revascularization . our patient had
4 months prior undergone bowel resection and sma endarterectomy with patch angioplasty with subsequent resolution of symptoms , but now presented a second time with ami .
given she did not want a potential bowel resection , and a flush sma occlusion which we could not cross antegrade , we resorted to trying to cross the sma in a retrograde fashion using the transcollateral wiring technique .
placing the support multipurpose catheter in the gda gave us enough purchase to use a microcatheter .
we prefer the progreat microcatheter due to its flexible tip , low profile , hydrophilic coating , and use of tungsten coil for kink resistance .
after reentry into the aorta and snaring of the wire , a through and through wire access across both brachial arteries was established .
it is important that subsequent pulling of this wire be smooth or inside the microcatheter , else a cheese cutting
this also protects against dissection of the arcade vessels . once we obtained antegrade sma access , we decided not to balloon the sma origin . due to the ease with which our wire passed retrograde , we were worried that there was thrombus present along with a stenosis and this was the cause for the occlusion . ballooning
thus , we directly placed an icast balloon - expandable covered stent which opens from the ends to the middle thus limiting a clot shower .
appropriate gantry angles are a must to make sure that there is enough stent projection into the abdominal aorta .
we preferred brachial access over femoral access in this case due to the steep angle of the sma which would have made passing the relatively stiff icast stent difficult from the groin .
given our worry that there was potentially thrombus present , thrombolysis and percutaneous aspiration are potential therapeutic options .
thrombolysis was not performed as it takes time and patient 's symptoms were more acute , needing acute mesenteric revascularization .
this usually necessitates losing wire access to the vessel to do the aspiration using a catheter which is pulled back across the thrombus .
given how hard it was to cannulate the sma initially and we had to go through the celiac artery , we did not think it was prudent to do percutaneous aspiration and lose access to the sma .
we have increasingly started to use covered stents rather than bare metal stents ( bms ) in the mesenteric vessels , especially if concerned about thrombus .
although these potentially require larger sheaths , limited reports in literature demonstrate much better long - term patency with covered stents versus bare metal stents ( 92% 3-year primary patency with covered stents vs 52% with bms by oderich et al ) . in conclusion , although unconventional , sma revascularization with retrograde transcollateral wiring technique is an important tool in the armamentarium of the vascular care specialist when antegrade percutaneous approach and open exposure via laparotomy are not an option .
Output:
| abstractrevascularization for acute mesenteric ischemia ( ami ) can be achieved through a bypass from the aorta or iliac arteries , embolectomy , open exposure of sma and retrograde recanalization and stent , or percutaneous antegrade stenting .
flush occlusion of the sma can make antegrade recanalization very challenging and is usually unsuccessful.we present a novel approach for recanalization of superior mesenteric artery ( sma ) via the celiac artery for acute mesenteric ischemia . a 69-year - old lady with previous endarterectomy of sma and extensive small bowel resection presented with severe abdominal pain , emesis , leukocytosis , and imaging finding of new sma flush occlusion .
she refused to consent for a laparotomy .
percutaneous retrograde transcollateral recanalization of sma was performed via the celiac artery through the pancreaticoduodenal arcade , and the sma then stented .
this resulted in subsequent resolution of patient 's symptoms and discharge.sma revascularization with retrograde transcollateral wiring technique is an important tool in the armamentarium of the vascular care specialist when antegrade percutaneous approach and open exposure via laparotomy are not an option . |
PubmedSumm6591 | ***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: age - related macular degeneration ( amd ) is the most common cause of blindness in industrialized countries affecting individuals over the age of 55 .
neovascular amd affects only 1015% of amd patients but approximately 90% of blindness due to this condition . the main cause of vision loss in neovascular amd is the development of choroidal neovascularization , which is ultimately the result of a break in a structural layer beneath the retina known as bruch 's membrane , which separates the nourishing vascular layer called the choroid from the retina .
these vessels can leak fluid or blood , initially distorting or blurring vision , and may eventually lead to scar in the macula and severe loss of central vision .
erectile dysfunction ( ed ) is defined as the inability to attain or maintain the penile erection required for sufficient sexual performance .
ed is a multifactorial disease ; the vascular , neurogenic , hormonal , psychogenic , cavernosal , iatrogenic , and anatomic causes lie in its pathophysiology .
the impact of ed can be devastating because evidence has shown that sexual function is one of the very important indices of quality of life .
cross - sectional studies have reported that ed is strongly associated with diabetes mellitus , hypertension , cardiovascular disease , hyperlipidemia , metabolic syndrome , depression , and lower urinary track symptoms [ 915 ] .
medication and recreational drugs are also associated with male sexual disorders , especially the use of antipsychotic drugs .
new epidemiological studies show an increase in the prevalence rates for ed in men who smoke as a standalone risk .
also , obesity , low testosterone levels , poor quality of life , apnoea - hypopnoea , and obstructive sleep apnoea syndrome were significantly associated with a higher risk of ed . to the best our knowledge , the association between neovascular amd and ed has not been evaluated before . in this cross - sectional study , we aim to investigate the relationship between ed and neovascular amd .
this prospective , cross - sectional study was conducted at the ophthalmology clinic between december 2012 and march 2013 .
the study was conducted according to the declaration of helsinki , the european guidelines on good clinical practice , and relevant national and regional authority requirements and the university 's ethics committees . all subjects signed informed consent forms before participating in the study .
ninety sexually active men with neovascular amd ( group 1 ) , who presented to our clinic , enrolled in the study . the control group ( group 2 ) was formed with the participation of 105 randomly chosen healthy volunteers from among those in the outpatient clinic .
patients with diabetes mellitus , hypertension , hyperlipidemia , heart disease , or other known systemic diseases ( such as depression , stroke , and medications ) and/or smokers were excluded .
the international index of erectile function ( iief ) is a widely used , multidimensional self - report instrument for the evaluation of male sexual function .
the presence and severity of ed were determined by calculating the ef domain of the questionnaire ( ef score ) . because we aimed to evaluate ef
the responses to all the six questions of the ef domain were added to arrive at a total ef score , with a range from six to 30 .
the six items on the ef domain include detailed questions concerning erection frequency , erection firmness , penetration ability , maintenance frequency , maintenance ability , and erection confidence .
ed severity was rated as no ed if scored from 26 to 30 , mild ed if scored from 17 to 25 , moderate ed if scored from 11 to 16 , and severe ed if scored from 6 to 10 .
we separated the patients according to their binocular vision ( low vision or not ) and patients were divided into two groups with or without binocular vision higher than 0.3 .
amd was diagnosed with fundoscopic retinal examination , fundus fluorescein angiography , and optical coherence tomography .
data analysis was performed with spss ( statistical package for social sciences ) , version 17.0 .
the kolmogorov - smirnov test was used to assess the normality of numeric variables . for the normally distributed variables , comparison between the two groups
was made by the independent sample t test and one - way anova , and the results were expressed as mean standard deviation . for the nonnormally distributed variables , comparison between two groups
was made by the mann whitney u - test and the descriptive statistics were expressed as median ( 2575 percentiles ) .
demographic characteristics of participants for both groups are presented in table 1 . in group 1 , there were 90 men with a mean age of 62 years , ranging from 54.5 to 73 . in group 2 , there were 105 men with a mean age of 60 years , ranging from 54 to 68 .
the results of the ef domain score revealed that 50 patients ( 55.6% ) had severe ed , 20 patients ( 22.2% ) had moderate ed , 15 patients ( 16.7% ) had mild ed , and 5 patients ( 5.6% ) had no ed . in group 2 , the results of the patients ' ef domain score revealed that 33 ( 31.4% ) had severe ed , 16 ( 15.2% ) had moderate ed , 19 ( 18.1% ) had mild ed , and 37 ( 35.2 % ) had no ed .
patients with neovascular amd had a significantly higher incidence of ed than control patients ( p < 0.01 ) .
there was a significant association between ed and neovascular amd ( p < 0.01 ) . according to binocular vision classifications
, there were 49 and 98 men whose binocular vision was higher than 0.3 in groups 1 and 2 , respectively .
similarly , there were 41 and 7 men with a binocular vision of 0.3 or lower in groups 1 and 2 , respectively . in group 1 ,
97.6% of the subjects with binocular vision of 0.3 or lower had ed . in group 2 , all of the participants with binocular vision of 0.3 or lower had ed .
62.2% of controls with good vision ( va > 0.3 ) had ed , while 91.8% of amd patient with good vision had ed .
there was no statistically significant difference according to ed and visual level in neovascular amd group ( p = 0.16 ) .
conversely , in control group , the difference was statistically significant ( p = 0.03 ) ( figure 2 ) .
bmi was calculated ( kg / m ) and subjects were categorized as normal ( 22 to 24.9 kg / m ) , overweight ( 2529.9 kg / m ) , or obese ( 30 kg / m ) according to their bmi values .
mean bmi was 26.71 3.1 and 25.87 4.1 , in groups l and 2 , respectively .
there were 22 normal weight men , 53 overweight men , and 15 obese men in group 1 .
there were 47 normal weight men , 43 overweight men , and 15 obese men in group 2 .
93.3% of obese men , 94.7% of overweight men , and 95.5% of normal weight men were found to have ed in group 1 . while in control group only 12 overweight subjects had severe ed in amd group , 33 overweight subjects ( nearly three times as many as controls ) had severe ed .
6 subjects had moderate ed , while in amd group 13 subjects had moderate ed ( p < 0.01 ) ( table 2 ) .
we separated the subjects according to their ages . in group 1 , all subjects had ed in the 4th and 5th decades . in the 6th decade and over the age of 70 , 87.5% and 96.7% of patients had ed , respectively .
46.2% of patients in the 4th decade and 56.1% of patients in the 5th decade were found to have ed in group 2 . in the 6th decade and over the age of 70 , 71% and 85% of patients had ed , respectively ( table 3 ) .
the association between neovascular amd and ed has never been elucidated in the literature . in the present study
diabetes mellitus , hypertension , stroke , chronic kidney disease , atherosclerosis , abnormalities of lipid metabolism , hyperlipidemia , and cardiovascular disease are positively associated with amd [ 21 , 22 ] .
also , several studies have attempted to assess the relationship between ed and risk factors such as diabetes mellitus , depression , cardiovascular disease , smoking , hypertension , increased age , hypogonadism , hyperprolactinemia , and hyperparathyroidism . in the control group among patients with no risk factors or any of the medical comorbidities
this prevalence and severity of ed seem to be high for controls . on the other hand ,
these results were found to be much more higher in neovascular amd group . in neovascular amd group among patients with no risk factors or any of the medical comorbidities
first , both choroid and penis have a rich vasculature and impaired microcirculation has been disclosed in the choroids of patients with neovascular amd and in the penises of men with ed [ 2224 ] .
second , some recent studies have demonstrated that disorders with endothelial dysfunction are associated with ed .
third , nitric oxide ( no ) is particularly important ; vasodilation is essential for erection , and no has the trigger role for vasodilation in the vascular endothelium .
several clinical trials have shown soluble markers related to endothelial dysfunction , for example , sicam-1 .
there is considerable evidence implicating endothelial dysfunction and cellular oxidative stress in the pathogenesis of both amd and ed .
potential mechanisms include endothelial dysfunction , metabolic syndrome and diabetes , altered endocrine function , social and psychological problems , and obstructive sleep apnoea , as well as ordinary physical disabilities .
lifestyle factors such as smoking , high alcohol intake , poor diet , and physical inactivity may also influence sexual dysfunction [ 29 , 30 ] .
interestingly , these observations were not corroborated by paick et al . who did not find a significant relationship between ed severity and metabolic syndrome , bmi , hormones , lifestyle .
no associations were found for either men or women between bmi and sexual satisfaction within their relationship .
our study revealed a statistically significant relationship between bmi and ed in control group ( p = 0.01 ) .
we also did not find any strong association between bmi and ed in neovascular amd group ( p = 0.121 ) .
depression is characterized by loss of interest , reduction in energy , lowered self - esteem , and inability to experience pleasure .
this constellation of symptoms may be expected to produce difficulties in sexual relationships and depression has long been associated with sexual problems .
several studies indicate that low vision secondary to amd is a risk factor for depression and this has serious consequences for the quality of life among patients with amd .
depression and stress are also psychogenic factors of ed and stress - related characteristics are found in patients with amd .
augustin et al . found that the prevalence of depression increased as visual impairment became more severe .
rates ranged from 14.3% for those with minimal vision loss to 25% for those with severe vision loss .
the prevalence of depression was also high among older adults who sought low vision rehabilitation services . in ophthalmology practice ,
if binocular vision is lower than 0.3 , it is called low vision .
low vision results in depression and connected with this ; depression also results in ed .
we separated the patients according to their binocular vision ( low vision or not ) and we could clarify if the ed is because of amd or low vision . in control group
those patients whose binocular vision was 0.3 or lower had a significantly higher incidence of ed than patients with good binocular vision .
interestingly , in neovascular amd group there was no association between visual levels and ed .
tsai et al . demonstrated epidemiological evidence of a significantly increased ratio of ed among patients with central serous chorioretinopathy ( cscr ) diagnosis .
they claimed that some factors like glucocorticoids , microvascular pathologies , and endothelial dysfunction prone to inducing cscr could also have a harmful effect on ef .
there are many similar risk factors between the etiology and pathogenesis of amd and ed . to the best of our knowledge
, this study is the first study that shows the association between neovascular amd and ed .
Output:
| purpose . to evaluate association between erectile dysfunction ( ed ) and
neovascular age - related macular degeneration ( amd ) . methods .
195 men enrolled in this cross - sectional study .
90 of them had neovascular amd and 105 of them were healthy volunteers .
the international index of erectile function ( iief ) questionnaire 's erectile function ( ef ) domain was used to assess ed .
the patients in the study and control groups were statistically compared according to visual acuity , ef score , and body mass index .
results .
the mean ages were 62 ( 54.573 ) and 60 ( 5468 ) , in the neovascular amd and control groups , respectively .
the total ef scores were 9 ( 616 ) in neovascular amd and 18 ( 9.527 ) in control group .
the results of iief questionnaire on neovascular amd patients revealed that 85 men ( 94.4% ) had some degree of ed , whereas 68 men ( 64.8% ) had some degree of ed on control group .
patients with neovascular amd had a significantly higher incidence of ed than control patients ( p < 0.01 ) .
there was a significant association between ed and neovascular amd ( p < 0.01 ) .
conclusions .
our results suggested that neovascular amd has a high association with ed . |
PubmedSumm6592 | ***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 difficulties include cold welding between the screw head and locking screw hole , stripping of the recess of the screw head for the screwdriver , and cross - threading between threads in the screw head and screw hole . however , there are cases in which removal is difficult .
we describe a new technique for removing a round headed , jammed locking screws from a locking plate .
55 years old male patient received a locking distal tibial plate along with distal fibular plate 3years back from uae .
now patient came with complaint of non - healing ulcer over medial aspect of lower 1/3rd of right leg from past 1 year .
the patient consented to implant removal , with the express understanding that implant removal might be impossible because already one failed attempt had been performed at some other hospital six months back .
we used stainless steel metal cutting blades that are used to cut door locks or pad locks to cut the remaining stripped headed screws .
this technique is very quick , easy to perform and inexpensive because the metal cutting blades which are used to cut the screws are very cheap .
yet it is very effective technique to remove the stripped headed or jammed locking screws .
it is also very less destructive because of very less heat production during the procedure there is no problem of thermal necrosis to the bone or the surrounding soft tissue .
these difficulties include cold welding between the screw head and locking screw hole , stripping of the recess of the screw head for the screwdriver , and cross - threading between threads in the screw head and screw hole .
these include using a conical extraction screw , cutting the plate , and using high - speed carbide drill bits and burrs to remove the screw heads , and removing the shanks with conical extraction screws .
the available screw removal kits make implant removal successful more often than not . however , there are cases in which removal is difficult .
we describe a new technique for removing a round headed , jammed locking screws from a locking plate .
preoperative antero - posterior and lateral view showing locking plate in distal tibia with 5 distal locking screws and 5 proximal locking screws .
the 55 years old male patient received a locking distal tibial plate along with distal fibular plate 3years back from uae . now
patient came with complaint of non healing ulcer over medial aspect of lower 1/3rd of right leg from past 1 year .
the patient consented to implant removal , with the express understanding that implant removal might be impossible because already one failed attempt had been performed at some other hospital six months back .
we used the ao synthes screw extraction kit along with conical extraction screw ( ao synthes ) but the screws did not come out .
we used stainless steel metal cutting blades that are used to cut door locks or pad locks to cut the remaining stripped headed screws .
firstly , after exposing the plate to be removed a space is created between locking plate and bone adjacent to screws to be cut with the help of sharp osteotome .
then an iron cutting blade which was previously autoclaved introduced between plate and bone adjacent to screws to be cut and with to and fro motion all the remaining screws were cut .
the remaining threaded parts of screws were left in the bone because there removal may further weaken the bone .
screws were cut with care with slow to and fro motion of blades but with firm pressure on blade to avoid any unnecessary soft tissue injury .
it only takes 10 minutes to cut all the remaining 4 proximal screws and there was no heating problem during the cutting of screws as there is with other procedures such carbide drills and high speed burrs . at the end of the procedure ,
we name this technique as rohit s technique for removal of stripped headed / jammed interlocking screws .
implant removal is considered for pain related to implants , part of treatment , and patient - requested implant removal .
risks of implant removal include wound - healing problems , neurovascular injury , failure to remove all of the implant , and refracture .
difficulties in removing a titanium locking screw include jammed screws , damage to the recess in the screw head ( stripping ) for the screwdriver , and broken screws .
instruments including conical extraction screws , hollow reamers , extraction bolts , modular devices , and carbide drill bits have been described in the methods used for removing locking screws [ 2 , 6 ] .
it also is accepted that no one technique can solve all problems in implant removal .
we believe failure to remove the distal screws directly with the conical extraction screw was attributable to the following factors : jamming of the screw head in the locking screw hole , owing to cross - threading and not necessarily cold welding ; grip of the screw threads in the far cortex ; bony growth over the titanium screw at the far cortex ; and as the conical extraction screw was inserted , the screw head jammed farther in the screw hole by expanding the screw head .
there is always the danger of thermal bone necrosis or iatrogenic bony injury when using high speed burrs and discs .
but our technique is less destructive as produces very less heat as compared to any others because it is not mechanical but a manual procedure .
intraoperative picture showing remaining threaded part of screws in the bone afte removal of plate along with jammed / stripped heads of screws .
post operative picture of removed tibial plate along with jammed screws in plate that are cut along the undersurface of plate .
it is essential to have all the appropriate implant removal instruments , including carbide drill bits and high - speed burrs and discs , and prepare for a long procedure .
the risks of high - speed burrs and discs are high local temperature and metal debris .
this technique requires running normal saline solution and continuous suction to remove all the metal debris .
this technique is very quick , easy to perform and inexpensive because the metal cutting blades which are used to cut the screws are very cheap .
yet it is very effective technique to remove the stripped headed or jammed locking screws .
it is also very less destructive because of very less heat production during the procedure there is no problem of thermal necrosis to the bone or the surrounding soft tissue .
inexpensive & effective method for removal of such implants which are extremely difficult as a result of round headed , cold welding and jammed locking screws heads .
Output:
| introduction : the advent of locking plates has brought new problems in implant removal .
difficulty in removing screws from a locking plate is well - known .
these difficulties include cold welding between the screw head and locking screw hole , stripping of the recess of the screw head for the screwdriver , and cross - threading between threads in the screw head and screw hole . however , there are cases in which removal is difficult .
we describe a new technique for removing a round headed , jammed locking screws from a locking plate.case report:55 years old male patient received a locking distal tibial plate along with distal fibular plate 3years back from uae .
now patient came with complaint of non - healing ulcer over medial aspect of lower 1/3rd of right leg from past 1 year .
non operative management did not improve the symptoms .
the patient consented to implant removal , with the express understanding that implant removal might be impossible because already one failed attempt had been performed at some other hospital six months back .
we then decided to proceed with the new technique .
the rest of the proximal screws were removed using a technique not previously described .
we used stainless steel metal cutting blades that are used to cut door locks or pad locks to cut the remaining stripped headed screws.conclusion:this technique is very quick , easy to perform and inexpensive because the metal cutting blades which are used to cut the screws are very cheap .
yet it is very effective technique to remove the stripped headed or jammed locking screws .
it is also very less destructive because of very less heat production during the procedure there is no problem of thermal necrosis to the bone or the surrounding soft tissue . |
PubmedSumm6593 | ***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: sclerosing mucoepidermoid carcinoma with eosinophilia ( smece ) of the thyroid is a recently recognized primary malignant neoplasm of the thyroid gland associated with hashimoto 's thyroiditis / lymphocytic thyroiditis .
till now , cases have been reported in the literature that are diagnosed histologically . and
fine needle aspiration ( fna ) from smece often show nonspecific features and most often the diagnosis of a poorly differentiated or undifferentiated carcinoma is rendered in most of the cases ; but careful examination of cytological features and the background may sometimes be helpful in diagnosis . here , we describe the cytological features of this rare case along with its differential diagnosis .
a 35-year - old female presented with thyroid swelling for 3 years and ipsilateral lymph - node swelling of 6-month duration .
her physical examination revealed right - sided thyroid swelling of 4 cm 4 cm size and lymph - node of size 1.5 cm 1.5 cm .
her thyroid profile revealed mild hypothyroidism , while routine blood examination and serum calcitonin levels were within normal limits .
fna was performed with a 22-gauge needle from both thyroid as well from lymph node and on aspiration from both sites blood mixed material was obtained .
the richly cellular smears showed predominantly round to oval cells lying singly as well as in loosely cohesive clusters .
these cells had rounded hyperchromatic nuclei with an occasional prominent nucleus and a moderate amount of eosinophilic cytoplasm .
a few cell clusters showed squamoid differentiation in the form of pyknotic to densely compact nucleus and deeply orangophilic cytoplasm [ figure 1a ] . at a few paces , the cells formed ill - defined epithelial pearl - like structures and only very occasionally the cells showed intranuclear cytoplasmic inclusion ( inci ) [ figure 1b ] .
background population comprised predominantly of lymphocytes and a significant number of eosinophils ( 1 - 2 cells / hpf ) [ figure 1c ] .
the important negative findings were the lack of mucus - secreting cells and intermediate cells .
so , depending on the abovementioned cytological features , we made the diagnosis of a primary thyroid malignancy with squamous differentiation with a differential of poorly differentiated carcinoma , mucoepidermoid carcinoma with eosinophilia , and a metastasis from a different site .
( a ) smear reveals round to oval cells with hyperchromatic nuclei with a cell cluster showing deep cytoplasmic eosinophilia and dense compact chromatin ( h and e , 40 ) ( b ) tumor cells are forming epithelial pearl - like structure and a cell showing inci ( thin arrow ) ( h and e , 200 ) ( c ) background population consists of lymphocytes and eosinophils ( arrow ) ( h and e , 200 ) the patient underwent radical thyroidectomy .
histological diagnosis was further confirmed immunohistochemically as the tumor was positive for thyroid transcription factor-1 ( ttf-1 ) and cytokeratin and negative for thyroglobulin and calcitonin [ figure 2 ] .
( a ) histology showed island of squamoid cells embedded in a sclerotic stroma and dense eosinophil cell infiltrate ( h and e , 100 ) ( b ) normal thyroid parenchyma showed lymphocytic thyroiditis ( h and e , 200 ) ( c ) calcitonin negative ( calcitonin , 200 ) ( d ) ttf-1 positivity ( ttf-1 , 200 ) ( e ) thyroglobulin negative ( thyroglobulin , 200 ) ( f ) cytokeratin positive ( cytokeratin , 200 )
smece is a rare slow - growing neoplasm of thyroid described in adults between 35 years and 70 years of age with a female predominance ( female to male ratio 17:1 ) .
though a few studies have described its histological features , only an occasional reports have described the cytological features in which it has been described as a tumor with deceptively bland morphology or as carcinoma with cytoplasmic eosinophilia .
cytologically , smece should be differentiated from benign conditions showing squamous metaplasia as well as from primary thyroid neoplasm that can show foci of squamous differentiation such as papillary carcinoma , medullary carcinoma , conventional mucoeidermoid carcinoma , and primary or metastatic squamous cell carcinoma .
papillary thyroid carcinoma can be differentiated from smece by its characteristic nuclear features such as nuclear clearing , nuclear grooves , and inci .
although , inci is present in very occasional cells but the diagnostic nuclear character was absent in the cells , rather the nucleus was hyperchromatic in the cells .
medullary carcinoma have a characteristic nuclear chromatin pattern , i.e. , a salt - and - pepper pattern and usually lacks background population of lymphocytes and is usually associated with raised calcitonin levels .
primary squamous cell carcinoma is extremely rare and is classified as anaplastic carcinoma while this neoplasm usually has more nuclear atypia and pleomorphism and is frequently associated with necrosis that lacks a background population of lymphocytes and eosinophils .
most of the time straightforward cytological diagnosis of smece is not an easy task and on cytology there is often a dilemma about the diagnosis .
likewise , we put forth the differential of a poorly differentiated carcinoma with squamous differentiation and have kept the differential of smece owing to the absence of characteristic nuclear features of papillary and medullary carcinoma , the presence of hyperchromatic nuclei , and the background population of eosinophils and lymphocytes that suggest background thyroiditis .
histologically , smece is characterized by small nest and cords of tumor cells separated by fibrocollagenous sclerotic stroma and dense eosinophil cell infiltrate .
immunohistochemically , smece is negative for thyroglobulin and calcitonin and positive for ttf-1 and cytokeratin .
its constant association with hashimoto 's thyroiditis / lymphocytic thyroiditis has suggested that smece originates from the metaplastic squamous nest found in hashimoto 's thyroiditis / lymphocytic thyroiditis .
a few have suggested follicular origin . while others suggested origin from c cell , parathyroid , ectopic salivary gland , and thyroglossal duct . though the definitive cytological diagnosis of this rare neoplasm is very difficult and often has cytologically nonspecific features but whenever a thyroid tumor exhibits squamoid features with the absence of characteristic nuclear features of papillary and medullary thyroid carcinoma one must keep the differential of smece . there are no conflicts of interest .
Output:
| sclerosing mucoepidermoid carcinoma with eosinophilia ( smece ) of the thyroid is a rare primary thyroid tumor arising in a background of hashimoto's / lymphocytic thyroiditis and has been recently introduced in the world health organization ( who ) classification of thyroid tumors .
it is characterized by extensive sclerosis , squamous and glandular differentiation , and inflammatory infiltrate rich in eosinophil . here
, we are discussing the cytological features of this rare case in a 35-year - old female presented with thyroid swelling and lymph - node enlargement . |
PubmedSumm6594 | ***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:
| molecular markers such as mutational spectra or mrna expression patterns may give some indication of the mechanisms of carcinogenesis induced by fibers and other carcinogens . in our study , tumors were induced by application of crocidolite asbestos or benzo[a]pyrene ( b[a]p ) to rat peritoneum .
dna and rna of these tumors were subjected to analysis of point mutations and to investigation of mrna expression patterns . with both assays we found typical features depending on the type of carcinogen applied .
the analysis of point mutations in the tumor suppressor gene p53 revealed mutations in the b[a]p - induced tumors .
however , in the tumors induced by crocidolite asbestos that were of the same tumor type as those induced by b[a]p , mutations in p53 were not detectable . every mutation detected on the dna level causes an amino acid substitution within one of the functional domains of the tumor suppressor protein .
therefore , these mutations seem to be of biological relevance for tumor progression and indicate a difference in the carcinogenesis regarding the type of the carcinogenic substance . an additional specificity of crocidolite - induced tumors was detectable by analyzing the mrna expression of the tumor suppressor gene wt1 , which is known to be expressed in human mesothelial and mesothelioma cells .
a relatively high amount of wt1 mrna was measured by quantitative competitive reverse transcription - polymerase using rna extracted from crocidolite - induced tumors .
however , wt1 seems to be expressed on a rather low level in tumors induced by b[a]p.imagesfigure 1.figure 2.figure 2.figure 2.figure 2 . |
PubmedSumm6595 | ***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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Input: an essential development in the evolution of multicellular organisms with a variety of tissues serving different functions has obviously been the formation of specific semi - stable and dynamic cell - cell junctions , i.e. , architectonically positioned structures of limited size that connect cells of the same or different types into higher order organs .
laterally , i.e. , in the same plasma membrane , such assemblies can be homophilic or heterophilic and are generally oriented head - to - head , usually with distinct substructures .
in present textbooks of cell biology , four major categories of cell - cell junctions are distinguished ( table 1 ; for a historic review , see franke 2009 ) :
gap junctions ( nexus ) appear as densely packed hemichannels composed of tetraspan membrane proteins , which belong to the connexin family and which are symmetrically oriented into channels that allow cell - cell exchange of small molecules.tight junctions ( tj ; zonulae or fascial adhaerentes ) are arrays of tetraspan transmembrane proteins forming tight - sealing bands of various lengths , often branched or ornamentally woven .
these proteins are arranged head - to - head into membrane barrier structures containing cell - type - specific combinations of the claudin and the occludin families of proteins , mostly in association with specific immunoglobulin - like proteins of the junction adhesion molecule ( jam ) group spanning the membrane once.adherens junctions ( aj ) are a group of variously sized and shaped cell - type - specific assemblies of glycoproteins of the cadherin family spanning the membrane once and capable of forming a continuous cell - surrounding belt ( zonula adhaerens ) or streak - like fascia adhaerens , or local near - isodiametric puncta adhaerentia.generally the thickest and most robust junction type is represented by the desmosomes ( maculae adhaerentes ) formed by special subsets of cadherins ( desmogleins , desmocollins).table 1molecular components of the major categories ( i iv ) and several other forms ( 17 ) of mammalian symmetrical ( homotypic ) junctions ( jam junction adhesion molecule , brackets not regularly seen in all cells , nd not decided as yet)typeoccurrenceassociated filamentstransmembrane proteins and glycoproteinsspecific plaque proteins ( selection of hallmark representatives)i .
desmosomes maculae adhaerentesepithelial cellsintermediate - sized filaments ( keratins , vimentin , desmin)desmogleins dsg 13plakoglobincardiomyocytesdesmoplakinsmeningothelial cellsdesmocollins dsc 13plakophilins 13reticulum cells of thymus and lymph folliclesii .
adherens junctions zonulae adhaerentesepithelial cellsmicrofilaments ( actin)typical cadherins ( e.g. , e - cadherin , n - cadherin , ve - cadherin , cadherin-11 ) nectin- and -catenin , plakoglobin , protein p120 , protein arvcf , protein p0071 , neurojungin , proteins zo-1 - 3 , afadin , vinculinendothelial cells fasciae adhaerentesvarious types of cardiomyocytes puncta adhaerentiamesenchymal and neural cellsiii .
minimal dot junctions puncta adhaerentia minimamesenchymal cellsmicrofilaments ( actin)n - cadherin , cadherin-11- and -catenin , proteins p120 , p0071 , arvcf , ( plakoglobin ) , afadin 2 .
taproot adherens junctions manubria adhaerentiamesenchymal cells in culturemicrofilaments ( actin)n - cadherin , cadherin-11- and -catenin , ( plakoglobin ) , proteins p120 , p0071 , arvcf , proteins zo-1 - 3 , afadin , vinculin 3 . plakophilin-2-containing adherens junctions coniunctiones adhaerentesmesenchymally derived cells of high proliferative activitymicrofilaments ( actin)n - cadherin , cadherin-11 ( nectin)- and -catenin , plakoglobin , proteins p120 and p0071 , plakophilin-2 , ( plakophilin-3 ) , proteins zo-1 - 3 , afadin , vinculin 4 .
composite junctions areae compositaecardiomyocytes of maturing and adult heartmicrofilaments ( actin)n - cadherindesmoplakin , - and -catenin , proteins p120 , arvcf and p0071 , plakophilin-2 , proteins zo-13cadherin-11intermediate - sized filamentsdesmoglein-2desmocollin-2 5 .
adherens cortex cortex adhaerenseye lens interiorndn - cadherin , cadherin-11- and -catenin , plakoglobin , protein p120 , ezrin , periplakin , periaxin 6 .
sandwich junctions iuncturae structaeepidermal stratum spinosum or equivalent layers of other stratified epitheliandoccludin , claudinsnd 7 .
complex junctions complexus adhaerentesendothelial and virgultar cells of lymph node sinusndn - cadherindesmoplakin , - and -catenin , protein p120 , plakoglobin , proteins zo-13 , afadincadherin-11ve - cadherinclaudin-5jam proteinsone isoform or combinations of a few representatives , often with cell - type and cell - layer specificitiesonly cell - type - specific combinations of the armadillo - type proteins underlinedthere are two mrna splice products of which only one protein has so far been localizedactin microfilaments are seen near the junctions , but their specific association is not clearplakoglobin has been demonstrated only in some cells and with markedly differing intensities , even in the same cultureplakophilin-3 has been seen only in a portion of plakophilin-2-positive cells gap junctions ( nexus ) appear as densely packed hemichannels composed of tetraspan membrane proteins , which belong to the connexin family and which are symmetrically oriented into channels that allow cell - cell exchange of small molecules .
tight junctions ( tj ; zonulae or fascial adhaerentes ) are arrays of tetraspan transmembrane proteins forming tight - sealing bands of various lengths , often branched or ornamentally woven .
these proteins are arranged head - to - head into membrane barrier structures containing cell - type - specific combinations of the claudin and the occludin families of proteins , mostly in association with specific immunoglobulin - like proteins of the junction adhesion molecule ( jam ) group spanning the membrane once .
adherens junctions ( aj ) are a group of variously sized and shaped cell - type - specific assemblies of glycoproteins of the cadherin family spanning the membrane once and capable of forming a continuous cell - surrounding belt ( zonula adhaerens ) or streak - like fascia adhaerens , or local near - isodiametric puncta adhaerentia .
generally the thickest and most robust junction type is represented by the desmosomes ( maculae adhaerentes ) formed by special subsets of cadherins ( desmogleins , desmocollins ) .
molecular components of the major categories ( i iv ) and several other forms ( 17 ) of mammalian symmetrical ( homotypic ) junctions ( jam junction adhesion molecule , brackets not regularly seen in all cells , nd not decided as yet ) one isoform or combinations of a few representatives , often with cell - type and cell - layer specificities only cell - type - specific combinations of the armadillo - type proteins underlined there are two mrna splice products of which only one protein has so far been localized actin microfilaments are seen near the junctions , but their specific association is not clear plakoglobin has been demonstrated only in some cells and with markedly differing intensities , even in the same culture plakophilin-3 has been seen only in a portion of plakophilin-2-positive cells in addition , these junctions are associated , on their cytoplasmic face , with specific ensembles of coating proteins , which again display similarities and junction - type - specific differences :
gap junctions do not reveal a distinct , i.e. , electron microscopically demonstrable cytoplasmic plaque , but their connexins are complexed with cytoplasmic proteins of the membrane - associated guanylate kinase ( maguk ) family , which in turn can interact with microtubules or actin filaments ( see anthology by peracchia 2000).tjs are also associated with a thin and barely visible coat containing maguk proteins , specifically proteins zo-1 zo-3 , plus cingulin and a series of other proteins ( see anthology by cereijido and anderson 2001 , notably therein the review by citi 2001).ajs are characterized by clearly demonstrable plaque structures of varying thickness , made up of cell - type - specific combinations of armadillo ( arm)-type proteins , e.g. , plakoglobin , -catenin , proteins p120 , p0071 , and arvcf , and neurojungin , together with vinculin - like or other actin - binding proteins such as -catenin , vinculin , and afadin ( for reviews , see the anthologies of behrens and nelson 2004 ; laflamme and kowalczyk 2008).the plaques of desmosomes , the cadherins of which can project into ( and even through ) the mostly prominent and dense plaque , also contain plakoglobin , but in addition plakophilin-2 or combinations of two plakophilins , together with the special plaque protein , desmoplakin ( for reviews , see the aforementioned anthologies and holthfer et al . 2007 ;
gap junctions do not reveal a distinct , i.e. , electron microscopically demonstrable cytoplasmic plaque , but their connexins are complexed with cytoplasmic proteins of the membrane - associated guanylate kinase ( maguk ) family , which in turn can interact with microtubules or actin filaments ( see anthology by peracchia 2000 ) .
tjs are also associated with a thin and barely visible coat containing maguk proteins , specifically proteins zo-1 zo-3 , plus cingulin and a series of other proteins ( see anthology by cereijido and anderson 2001 , notably therein the review by citi 2001 ) .
ajs are characterized by clearly demonstrable plaque structures of varying thickness , made up of cell - type - specific combinations of armadillo ( arm)-type proteins , e.g. , plakoglobin , -catenin , proteins p120 , p0071 , and arvcf , and neurojungin , together with vinculin - like or other actin - binding proteins such as -catenin , vinculin , and afadin ( for reviews , see the anthologies of behrens and nelson 2004 ; laflamme and kowalczyk 2008 ) .
the plaques of desmosomes , the cadherins of which can project into ( and even through ) the mostly prominent and dense plaque , also contain plakoglobin , but in addition plakophilin-2 or combinations of two plakophilins , together with the special plaque protein , desmoplakin ( for reviews , see the aforementioned anthologies and holthfer et al . 2007 ; waschke 2008 ) .
in recent years , a series of conspicuous cell - type - specific forms of symmetrical cell - cell junctions with diverse shapes , sizes , and unusual molecular ensembles or complexities have been ultrastructurally and analytically characterized to a considerable degree .
these studies have strengthened the conclusion that the structures under question are special junctions in their own right .
their characteristic structures and molecular ensembles known so far will be briefly described here and their possible functional significance will be discussed .
puncta adhaerentia minima ( minimal dot junctions ) puncta adhaerentia minima ( minimal dot junctions ) extremely small ajs have been found on the surfaces of several kinds of mesenchymally derived cells grown in cell culture , in particular in cultures of specific subsets of bone - marrow- , placenta- , or adipose - tissue - derived mesenchymal stem cells ( mscs ) and in cultures of interstitial cells derived from specific organs such as the matrix of cardiac valves .
sparse cultures of such mesenchymally derived cells are characterized by the frequent occurrence of filopodia - like cell processes of widely variable lengths , including some that may even exceed 400 m and that are studded in varying frequencies and patterns with punctate , often extremely small ( 2050 nm diameter ) ajs ( fig .
1a c ; see , e.g. , wuchter et al . 2007 ; barth et al .
in other words , the diameters of the smallest of these ajs are not much greater than those of nearby microtubules .
these minimal - size ajs ( puncta adhaerentia minima ; pam ) are clearly different from the aj - like structures located in the shorter " zipper " bridge structures connecting cultured murine keratinocytes ( vasioukhin et al .
light- and electron - microscopic immunolocalization , supported by the analytical biochemistry of total cell junctional proteins , have allowed the identification of n - cadherin and cadherin-11 in these pam , together with - and -catenin , protein p120 , and afadin as regular components ( e.g. , fig .
2007 ; for " normal - size " ajs of mesenchymal cells in culture , see , e.g. , hinz et al .
, we have also localized the arm - protein p0071 in such pam , whereas plakoglobin has been repeatedly seen in some of cell cultures but only sporadically noted in others ( cf .
1double - label immunofluorescence ( a , e - g ) and electron ( b , c ) and immunoelectron ( d ) microscopy showing cell processes of cultured human mesenchymal stem cells ( mscs ) , originally isolated from bone marrow ( a - d ) or ovine cardiac valve matrix ( e - g ) . a note that some of the cell processes are extremely long . the giant process extending in the lower part ,
for example , exceeds 450 m in length and forms adherens junctions ( ajs ) of the puncta adhaerentia minima type ( pam ) with at least five other cells .
the microfilament - rich cell process is immunostained for the actin - binding protein , ezrin ( ezrin , red ) , and the numerous ajs have reacted with antibodies specific for -catenin ( -cat , green ) .
b electron micrograph of the overlapping contact region of two cytoplasmic msc processes that partly overlap in the contact region ( bracket ) .
c higher magnification of the contact region demarcated in b showing a series of extremely small pam ( arrows ; e.g. , the diameter of the junction denoted by the arrow right is below 40 nm ) .
d immunoelectron microscopy of a similar region as that shown in c showing an overlap contact of processes of two cells ( a , b ) ; the processes are studded with pam decorated with silver - enhanced immunogold - label for -catenin ( arrowheads ) . for details , see wuchter et al .
g clusters of ajs at the tips of cell processes of cardiac valvular interstitial cells as visualized by immunostaining with antibodies to n - cadherin ( n - cad ; for details , see barth et al .
n - cadherin - positive ( red ) ajs connecting valvular interstitial cells ( green , vimentin ) are present as terminal punctate clusters at the tips of filopodium - like processes ( e.g. , the segment shown bottom in e exceeds 100 m in length ) .
note the clusters of small ajs connecting the central bodies of three valvular interstitial cells ( f ) and the relatively large region densely studded with ajs connecting the terminal portions of two cell processes ( g ) . for details , see barth et al .
bars 100 m ( a ) , 2 m ( b ) , 0.5 m ( c ) , 0.2 m ( d ) , 25 m ( e , f ) , 20 m ( g ) double - label immunofluorescence ( a , e - g ) and electron ( b , c ) and immunoelectron ( d ) microscopy showing cell processes of cultured human mesenchymal stem cells ( mscs ) , originally isolated from bone marrow ( a - d ) or ovine cardiac valve matrix ( e - g ) . a note that some of the cell processes are extremely long .
the giant process extending in the lower part , for example , exceeds 450 m in length and forms adherens junctions ( ajs ) of the puncta adhaerentia minima type ( pam ) with at least five other cells .
the microfilament - rich cell process is immunostained for the actin - binding protein , ezrin ( ezrin , red ) , and the numerous ajs have reacted with antibodies specific for -catenin ( -cat , green ) .
b electron micrograph of the overlapping contact region of two cytoplasmic msc processes that partly overlap in the contact region ( bracket ) .
c higher magnification of the contact region demarcated in b showing a series of extremely small pam ( arrows ; e.g. , the diameter of the junction denoted by the arrow right is below 40 nm ) .
d immunoelectron microscopy of a similar region as that shown in c showing an overlap contact of processes of two cells ( a , b ) ; the processes are studded with pam decorated with silver - enhanced immunogold - label for -catenin ( arrowheads ) . for details , see wuchter et al .
e g clusters of ajs at the tips of cell processes of cardiac valvular interstitial cells as visualized by immunostaining with antibodies to n - cadherin ( n - cad ; for details , see barth et al .
n - cadherin - positive ( red ) ajs connecting valvular interstitial cells ( green , vimentin ) are present as terminal punctate clusters at the tips of filopodium - like processes ( e.g. , the segment shown bottom in e exceeds 100 m in length ) . note the clusters of small ajs connecting the central bodies of three valvular interstitial cells ( f ) and the relatively large region densely studded with ajs connecting the terminal portions of two cell processes ( g ) . for details , see barth et al .
bars 100 m ( a ) , 2 m ( b ) , 0.5 m ( c ) , 0.2 m ( d ) , 25 m ( e , f ) , 20 m ( g ) small junctions of the aj type , including pam , have also been frequently observed on long processes and on other surface regions of cells in primary and secondary cultures of mesenchymal cells derived from other tissues such as the interstitial cells of the interior of cardiac valves from various mammalian species , including rat , sheep , cow , and human ( e.g. , fig .
1e - g ; for details see barth et al . 2009 ; and references cited therein ) . in such interstitial cell cultures ,
the small ajs are often clustered in specific regions of the filopodia , in particular at their tips , but may also occur on the central cell bodies ( fig .
again , the ajs of such cells , including pam , have been found to be positive for n - cadherin and cadherin-11 , for the arm - proteins -catenin , plakoglobin , proteins p120 , arvcf , and p0071 , and for -catenin , afadin , and proteins of the zo-1 group .
these puncta - studded long cell processes have to be distinguished from other long , thin and cylindrical filopodia - like actin - filament - rich cell - cell connections such as the cytonemata ( cytonemes ) described in drosophila and other invertebrate cells ( ramirez - weber and kornberg 1999 and further references therein ) and from the tunnelling nanotubes of various vertebrate cell systems ( rustom et al .
2004 ; gurke et al . 2008a , 2008b ; sowinski et al . 2008 ; gerdes 2009 ; gousset et al .
apparently , the presence of ajs , normal size - range or pam , provides a good criterion for distinguishing the aforementioned cell - cell junction - based contact systems from cytonemes and nanotubes and possibly from other cell - connecting filopodial structures .
manubria adhaerentia ( taproot adherens junction ) manubria adhaerentia ( taproot adherens junction ) in cultures of mesenchymally derived cells , we have also frequently noted a category of cell - cell junctions that has a highly conspicuous morphology and that often represents vast cell - cell contact areas ( wuchter et al .
these cells are characterized by processes that do not make distinct small aj contacts with the main cell bodies or with processes of other cells but deeply and tight - fittingly insert into special recesses of adjacent cells .
such taproot - like ajs ( manubria adhaerentia ) often occur in batteries of closely spaced structures of widely variable lengths ( the more frequently observed manubrium - type of short - to - medium lengths is seen in fig .
2a ) , occasionally with intracellular channel lengths of up to 50 m ( e.g. , fig .
in such long filopodia - filled invaginations , both membranes ( that of the filopodial process and that of the invagination recess ) are in close contact and are coated on the cytoplasmic and on the filopodial side by an apparently continuous plaque
. in some regions , this electron microscopically dense coat in some regions shows clustered , regularly spaced , extremely short spike - like projections into the cytoplasm ( see , e.g. , fig .
2c ) . thus , even at the electron - microscopic level , these taproot junctions often can be traced as essentially uninterrupted cylindrical aj - like structures with cell - cell contact surfaces of up to ca .
100 m , corresponding to 10 m and more per total cell , i.e. , a gigantic cell - cell contact area .
2double - label immunofluorescence microscopy ( a , b ) and conventional ultrathin section transmission electron microscopy ( c ) showing connections of mesenchymal human - bone - marrow - derived stem cells ( mscs ) , including filopodia - like cytoplasmic processes of widely variable lengths that either form direct intercellular bridges . a note that the cell shown here is connected to five other cells or deeply and tight - fittingly inserts into plasma membrane invaginations of an adjacent cell ( manubrium adhaerens ) .
b a series of such manubrial - type junctions of widely variable lengths , including examples up to 50 m long ( e.g. , top ) .
most of these taproot junction formations are almost continuously positive for n - cadherin ( n - cad , red in a , b ) and -catenin ( -cat , green in b ) , resulting in the yellow merge color .
the same structures are also positive for -catenin ( -cat , green in a ) , protein p120 ( not shown here ) , and cadherin-11 ( see also wuchter et al . 2007 ) .
c electron micrograph of a section through such a deep invagination tightly filled with a cell process from a neighboring cell forming a continuous plaque - like dense cytoplasmic coat over the entire length .
d representation showing a cell - cell junction of the manubrium adhaerens type and the resulting interlocking structure .
note that this form of structure essentially represents an extended aj structure in a special form ( inset cross - sectional image ) .
note also the continuous plaque system in the whole region . for further details , see wuchter et al .
bars 50 m ( a ) , 20 m ( b ) , 0.2 m ( c ) double - label immunofluorescence microscopy ( a , b ) and conventional ultrathin section transmission electron microscopy ( c ) showing connections of mesenchymal human - bone - marrow - derived stem cells ( mscs ) , including filopodia - like cytoplasmic processes of widely variable lengths that either form direct intercellular bridges . a note that the cell shown here is connected to five other cells or deeply and tight - fittingly inserts into plasma membrane invaginations of an adjacent cell ( manubrium adhaerens ) .
b a series of such manubrial - type junctions of widely variable lengths , including examples up to 50 m long ( e.g. , top ) .
most of these taproot junction formations are almost continuously positive for n - cadherin ( n - cad , red in a , b ) and -catenin ( -cat , green in b ) , resulting in the yellow merge color .
the same structures are also positive for -catenin ( -cat , green in a ) , protein p120 ( not shown here ) , and cadherin-11 ( see also wuchter et al . 2007 ) .
c electron micrograph of a section through such a deep invagination tightly filled with a cell process from a neighboring cell forming a continuous plaque - like dense cytoplasmic coat over the entire length .
d representation showing a cell - cell junction of the manubrium adhaerens type and the resulting interlocking structure . note that this form of structure essentially represents an extended aj structure in a special form ( inset cross - sectional image ) .
( 2007 ) . bars 50 m ( a ) , 20 m ( b ) , 0.2 m ( c ) that these manubrial cell - cell adhesion systems are indeed true aj structures is evident from their positive immunostaining reaction for both n - cadherin and cadherin-11 , together with a plaque structure positive for - and -catenin and proteins p120 , p0071 , and arvcf , whereas only weak and variable reactions for plakoglobin have been seen , and maguk proteins of the zo-13 group have not yet been identified with any significance ( table 1 ; see also wuchter et al .
. moreover , the manubria - filling filopodia typically are intensely reactive for actin and with antibodies to ezrin , moesin , myosin , and -actinin ( for the general -actinin - richness of the microfilament bundles , including the filopodia , of such cultured mscs , see also fig . 7 of wuchter et al .
we have found it impressive to follow the fate of these taproot junction structures as the cell - packing density increases with cell culture time .
such studies have demonstrated that the lengths of the cell processes and , correspondingly , of the invaginations dynamically decrease in a spectacular way so that , in cultures of extremely high density , only short residual manubria structures are seen ( see , e.g. , fig .
the changes of the molecular packing in these aj - related manubria junctions during this foreshortening phase will have to be studied in future experiments by using fluorescent - marker - coupled molecules in living cells .
for the sake of clarity , we wish finally to emphasize in this connection that the manubria adhaerentia structures only superficially resemble other kinds of " invaginations of cell processes " such as the filopodia - like zippers of vasioukhin et al .
( 2000 ) , the e - cadherin - based listeria engulfment structures ( hamon et al .
2006 ) , and the e - cadherin - aj - based cell - in - cell " entosis " structures described by brugge and collaborators ( e.g. , overholtzer et al . 2007 ) . however , that such filopodia - like processes may also occur in the body , at least at certain stages of development , is suggested by the observations of mesenchymal cells during and after mesoderm formation in mammalian embryos ( see , e.g. , franke et al . 1983 ; hashimoto and nakatsuji 1989 ; tam et al .
following such processes in their three - dimensional complexity in situ will clearly be difficult .
coniunctiones adhaerentes ( plakophilin-2-containing adherens junctions ) coniunctiones adhaerentes ( plakophilin-2-containing adherens junctions ) recently , we have found that a certain subset of ajs of mesenchymally derived cells grown in culture or as tumors in situ is markedly modified by the selective acquisition of plakophilin-2 , i.e. , an arm - group protein hitherto only known as a constituent of desmosomes of proliferatively active epithelial or epithelium - derived cells ( barth et al .
, this additional plaque protein in ajs seems to appear in a symmetrical fashion , i.e. , in both plaques of the two cells connected by the specific aj .
although ajs with the additional plakophilin-2 so far have been frequently seen in tumor - derived cell lines , this plakophilin-2-modified type of aj is clearly not restricted to cultures of malignantly transformed cells ( for non - transformed cells , see also rickelt et al .
2009 ) , as is shown with special clarity by the advent of this arm - protein in the ajs of cells growing in primary cultures of cardiac valvular interstitial cells ( fig . 3 ; barth et al .
3demonstration of the acquisition of plakophilin-2 ( pkp2 ) by some of the aj - related cell - cell junctions between human mesenchymal cells in culture .
a double - label immunofluorescence microscopy of cultured human bone - marrow - derived mesenchymal cells ( same culture as shown in fig .
1a - d ) immunostained for plakophilin-2 ( red ) , in combination with the aj protein , -catenin ( -cat , green ) .
co - localization of the two plaque proteins appears in yellow in limited regions of some of the cell - cell contacts .
b plakophilin-2 also shows co - localization with the aj - typical proteins , here with n - cadherin ( n - cad , green ) , in cells of cultures of cardiac valvular interstitial cells of human origin .
bars 20 m ( a ) , 100 m ( b ) demonstration of the acquisition of plakophilin-2 ( pkp2 ) by some of the aj - related cell - cell junctions between human mesenchymal cells in culture .
a double - label immunofluorescence microscopy of cultured human bone - marrow - derived mesenchymal cells ( same culture as shown in fig .
1a - d ) immunostained for plakophilin-2 ( red ) , in combination with the aj protein , -catenin ( -cat , green ) .
co - localization of the two plaque proteins appears in yellow in limited regions of some of the cell - cell contacts .
b plakophilin-2 also shows co - localization with the aj - typical proteins , here with n - cadherin ( n - cad , green ) , in cells of cultures of cardiac valvular interstitial cells of human origin .
bars 20 m ( a ) , 100 m ( b ) in this context , however , we consider it worth emphasizing that plakophilin-2 in general is a widespread near - ubiquitous component of all kinds of cells , i.e. , of cells lacking any desmosomes .
this protein appears to occur , albeit in low concentrations , as a component of certain nuclear complexes , including regulatory complexes ( mertens et al .
consequently , the advent of plakophilin-2 as an additional aj - plaque protein in mesenchymally derived cells does not reflect de novo synthesis but appears to be merely the result of an upregulation of the synthesis and stabilization of the protein product , perhaps only of certain posttranslational modifications .
obviously , the functional meaning of this dramatic increase of plakophilin-2 and its anomalous integration into ajs will have to be elucidated in the future , and we should also keep in mind that , in some of the cells with plakophilin-2-positive plaques , plakophilin-3 can also be detected as a junction plaque protein ( table 1 ; see also rickelt et al .
areae compositae ( composite junctions ) areae compositae ( composite junctions ) in non - mammalian vertebrates and during fetal stages of mammalian development , the cardiomyocytes of the heart are connected , for the most part , in regions rich in typical aj structures accompanied by a low proportion of desmosomes or at least desmosome - like - looking structures , representing about 10% or less of the cardiomyocyte contact surface area ( e.g. , mcnutt 1970 ; forbes and sperelakis 1985 ) .
however , mammalian heart development continues postnatally with the desmosomal and the aj structures clustering polarly into intercalated disks ( ids ) , and their two molecular ensembles mix and amalgamate ( fig . 4 ; franke et al .
4double - label immunofluorescence microscopy of cryostat sections through myocardium of an adult human heart , as seen after reactions with antibodies to desmoplakin ( dp , green ) , in combination with antibodies to ( red in each case ) desmoglein 2 ( dsg2 , a ) , n - cadherin ( n - cad , b ) , or the plaque protein arvcf ( c ) .
only the merged color ( yellow ) is seen presenting near - complete colocalization in the composite junctions ( areae compositae ) of the intercalated disks and thus representing the amalgamated form containing both desmosomal and aj proteins .
bars 20 m double - label immunofluorescence microscopy of cryostat sections through myocardium of an adult human heart , as seen after reactions with antibodies to desmoplakin ( dp , green ) , in combination with antibodies to ( red in each case ) desmoglein 2 ( dsg2 , a ) , n - cadherin ( n - cad , b ) , or the plaque protein arvcf ( c ) . only the merged color ( yellow )
is seen presenting near - complete colocalization in the composite junctions ( areae compositae ) of the intercalated disks and thus representing the amalgamated form containing both desmosomal and aj proteins .
bars 20 m consequently , in the ids of the mature mammalian heart , these junctional proteins and glycoproteins exist in almost a completely hybrid structure that has therefore been termed a composite junction
in these junctions , desmosomal molecules are no longer restricted to distinct structures but are major elements occurring in the entire plaque - coated region at which bundles of contractile myofilaments and of the desmin - rich intermediate filaments anchor ( kartenbeck et al .
1983 ; borrmann et al . 2006 ; franke et al . 2006 ; for protein p0071 , see hofmann et al .
this special merger of two major junction ensembles and the resulting hybrid character is also seen in the specific interaction of the desmosomal protein , plakophilin-2 , with the myocardium - typical aj plaque protein , -t - catenin ( goossens et al .
the importance of plakophilin-2 for i d assembly and function has also been demonstrated in mouse embryogenesis by using gene knock - out experiments ( grossmann et al .
2004 ) and in cardiomyocyte cultures by means of experiments involving short interfering mrna ( oxford et al . 2007 ; fidler et al . 2008 ; pieperhoff et al .
5immunoelectron micrographs of sections through intercalated disks ( ids ) of adult human heart . a survey image showing the localization of a desmosomal protein , desmoplakin , by an immunogold - silver enhancement reaction in the entire i d plaque of the area composita .
b details of the intense plaque reaction in both small and large i d subdivisions .
c an extended , continuous , completely plaque - covered , desmoplakin - rich junction ( for details , see franke et al .
bars 2 m ( a ) , 0.5 m ( b , c ) immunoelectron micrographs of sections through intercalated disks ( ids ) of adult human heart . a survey image showing the localization of a desmosomal protein , desmoplakin , by an immunogold - silver enhancement reaction in the entire i d plaque of the area composita . b details of the intense plaque reaction in both small and large i d subdivisions .
c an extended , continuous , completely plaque - covered , desmoplakin - rich junction ( for details , see franke et al .
bars 2 m ( a ) , 0.5 m ( b , c ) the recognition of a special composite junction in the ids of mature mammalian hearts has been valuable in finding a compelling explanation for the recently increasing number of reports that mutations , even small ones , in desmosomal proteins are highly correlated with ( and apparently causal for ) the so - called arrhythmogenic cardiomyopathies ( arvc ) , including major causes of sudden death , in young human beings , notably athletes ( table 2 ) . as about two thirds of the arvc cases genetically analyzed have been associated with specific mutations in genes encoding desmosomal proteins occurring in the composite junction ensemble ( for specific reviews , see also perriard et al . 2003 ; herren et al . 2009 ) , we are tempted to speculate that other mutations in i d proteins are responsible for the other third of arvc cases still to be elucidated .
table 2recent references reporting that certain mutations in human genes encoding desmosomal proteins and glycoproteins result in arrhythmogenic ventricular cardiomyopathies ( arvc ) and references to related topics and reviewsmoleculereferencesmoleculereferencerelated topics / reviewsreferenceplakophilin-2gerull et al .
awad et al . 2008 ; herren et al . 2009 ; corrado et al .
2007cortex adhaerens ( adherens cortex ) recent references reporting that certain mutations in human genes encoding desmosomal proteins and glycoproteins result in arrhythmogenic ventricular cardiomyopathies ( arvc ) and references to related topics and reviews cortex adhaerens ( adherens cortex ) an extreme situation of a systemic and near - complete aj - type integration of almost the entire cell - cell border is provided by the lens fibers , i.e. the internal tissue of the vertebrate eye , in which all the anucleate cell bodies are densely packed , leaving little free intercellular space and thus also contributing to the optical homogeneity of the lens . here , the cytoplasmic sides of the large plasma membrane contacts are coated by a giant cortical plaque - bearing structure , which , however , shows marked regional differences . in some regions , in particular at the short polar sides ,
this cortical complex represents a junction - equivalent that contains not only n - cadherin and cadherin-11 , but also classic plaque - components such as - and -catenin , plakoglobin , and protein p120 , although it seems to lack proteins p0071 and arvcf , afadin , and all desmosomal components .
in addition , various other proteins generally occurring on cell contact structures of the lens interior , such as ezrin , periplakin , and periaxin , are also seen in this part of the cortex ( fig .
long side is also positive for aj markers , including n - cadherin , with local exceptions of some gap junctions ( see , e.g. , fig .
6a ) , whereas in other parts of the lens , only the short sides are markedly immunostained for such aj molecules ( e.g. , fig .
by contrast , some other markers , in particular actin and actin - binding proteins such as ezrin , are present along the entire plasma membrane ( e.g. , fig . 6c ) .
fig
. 6double - label immunofluorescence microscopy of cryostat sections through bovine lens tissue presenting details of the cortex adhaerens . a comparison of the reaction for n - cadherin ( n - cad , red ) with that for the prominently gap - junction - associated protein zo-1 ( a , green ) , the actin - filament - associated protein ezrin ( b , green ) , and the aj plaque protein -catenin ( c , -cat , green ) .
note that here the zo-1 reaction appears to be restricted to a limited region in the longer lateral wall , whereas n - cadherin and -catenin are highly enriched at junction - like structures in the short wall elements .
( 2003 ) . bars 10 miuncturae structae ( sandwich junctions ) double - label immunofluorescence microscopy of cryostat sections through bovine lens tissue presenting details of the cortex adhaerens . a comparison of the reaction for n - cadherin ( n - cad , red ) with that for the prominently gap - junction - associated protein zo-1 ( a , green ) , the actin - filament - associated protein ezrin ( b , green ) , and the aj plaque protein -catenin ( c , -cat , green ) .
note that here the zo-1 reaction appears to be restricted to a limited region in the longer lateral wall , whereas n - cadherin and -catenin are highly enriched at junction - like structures in the short wall elements .
( 2003 ) . bars 10 m iuncturae structae ( sandwich junctions ) a true and trivial assertion is that tjs are recognized by localizations of tj molecules .
, that the localization of known tj molecules identifies a tj , can not be upheld as a general dogma ( cf .
table 1 ; cereijido and anderson 2001 ) . findings of tj protein reactions in various epithelial tissues , such as the stratum spinosum of stratified squamous epithelia and histologically related tissues of thymic hassall bodies and in squamous cell carcinomas , have been published but , until today , can not be reconciled with a zonula occludens or with related occluding structures , which to date in normal stratified epithelia have only been demonstrated in the uppermost living cell layer , the stratum granulosum ( e.g. , morita et al . 1998 ; brandner et al .
in contrast , several authors have shown that such tj proteins can also occur in strata spinosa , but that their immunoreactions often do not colocalize .
for example , some tj markers such as claudin-1 occur practically throughout the spinous layer of the epidermis and other stratified epithelia and in tissues lacking any lumen such as thymic hassall corpuscules and certain cell aggregates in squamous cell carcinomas , notably the so - called horn - pearls ( langbein et al . 2002 , 2003 ) .
indeed , corresponding immunoelectron microscopy has revealed that , in many of the interdesmosomal regions of these cell layers and tumors , an intense claudin-1 reaction is seen rather generally ( fig . 7 ; langbein et al .
2002 , 2003 ) . in the uppermost strata , some of these sites are also positive for occludin but not for other tj markers .
7immunoelectron microscopy of ultrathin sections through the stratified squamous epithelium of bovine tongue mucosa ( a - d ) or a hassall corpuscle of bovine thymus ( e ) , as seen after reaction with antibodies to occludin .
immunogold label is not only seen in the uppermost living cell layer , the stratum granulosum - equivalent ( for details see , e.g. , brandner et al . 2002 ; langbein et al .
2004 ) , but also in inconspicuous interdesmosomal regions ( arrows in a , b , d , e ) and in special junctions ( iuncturae structae ) with an electron - dense middle layer ( arrowheads in c , d ) .
tight junction ( tj ) proteins are not restricted to typical tjs but at least some of them also occur in additional , yet insufficiently characterized junctions ( d desmosomes ) .
bars 0.2 m ( a , b ) , 0.1 m ( c - e ) immunoelectron microscopy of ultrathin sections through the stratified squamous epithelium of bovine tongue mucosa ( a - d ) or a hassall corpuscle of bovine thymus ( e ) , as seen after reaction with antibodies to occludin .
immunogold label is not only seen in the uppermost living cell layer , the stratum granulosum - equivalent ( for details see , e.g. , brandner et al . 2002 ; langbein et al .
2004 ) , but also in inconspicuous interdesmosomal regions ( arrows in a , b , d , e ) and in special junctions ( iuncturae structae ) with an electron - dense middle layer ( arrowheads in c , d ) .
tight junction ( tj ) proteins are not restricted to typical tjs but at least some of them also occur in additional , yet insufficiently characterized junctions ( d desmosomes ) .
bars 0.2 m ( a , b ) , 0.1 m ( c - e ) whereas the stratum spinosum structures positive for specific tj markers are often small and inconspicuous , a special heavy metal staining reaction is recognized in some of them , resulting in the appearance of an electron - dense layer between the two plasma membrane domains ( fig . 7
911 of langbein et al . 2002 ) . depending on the thickness and the extent of this electron - dense middle layer in cell - cell contacts ,
lamellated junctions ( coniunctiones laminosae ) or as iunctura structa ( sandwich junctions ) .
finally , extremely small , i.e. punctate , tj - resembling structures have been seen in freeze - fractures preparations and have been tentatively termed puncta occludentia ( stud junctions ; cf . schlter et al .
as the existence of such tj - related structures in stratum spinosum structures and probably related layers in other stratified epithelia and in pathologically altered tissues derived therefrom now seems established , it is high time to characterize these tj - protein - positive structures that are not tjs in both structural and molecular terms .
complex junctions as early as 1990 , certain kinds of lymphatic endothelial cells , in particular those of the lymph node sinus , were noted to be characterized by special , highly unusual kinds of cell - cell junction , collectively referred to as complexus adhaerentes .
these junctions varied remarkably in their size and junctional architecture , including some excessively large structures .
they contained ve - cadherin , often in co- or almost co - localization with n - cadherin , and were not only positive for other typical endothelial junction markers such as - and -catenin , plakoglobin , p120 protein and afadin , but were also strongly positive for desmoplakin and for some typical tj proteins including , in certain positions , claudin-5 and jam - a ( fig . 8 , table 1 ; cf .
the unusual locations of , e.g. , desmoplakin in these lymphatic endothelial junctions was then confirmed and extended in several ways for other lymph node structures and for other parts of the lymphatic vascular system ( e.g. , valiron et al .
1996 ; ebata et al . 2001 ; baluk et al . 2007 ; pfeiffer et al .
strange morphology of the complex virgultar meshwork of the intrasinusoidal endothelial cell types and the close association of cytoplasmic wraps with collagen fiber bundles has been presented in detail elsewhere ( moll et al . 2009 ) .
however , the functional relevance of the different cell - cell junction ensembles in different parts of the lymphatic system ( subtypes of lymphatic endothelia are also positive for protein p0071 ; hofmann et al . 2008 ) remains to be elucidated .
the obvious importance of desmoplakin in angiogenesis during embryogenesis and in experimental systems ( kowalczyk et al .
1998 ; gallicano et al . 2001 ; zhou et al . 2004 ) also indicates that regional and developmental differences exist with regard to the influence of such complexus adhaerens - typical molecules .
8double - label immunofluorescence laser - scanning microscopy images of cryostat cross sections through human lymph nodes , showing the specific , mutually exclusive localization of ve - cadherin in the endothelium of small blood vessels ( v ) and the desmoplakin and -catenin immunoreactions in the complexus adhaerentes of the endothelial and virgultar cells ( sevcs ) of the sinus ( s ) .
a colocalization of desmoplakin and ve - cadherin in the complexus adhaerentes of sevcs cells in the sinus ( s ) can be seen with special clarity in the yellow merged image ( ve - cadherin , red versus desmoplakin , green ) .
b corresponding merged image showing co - localization ( yellow ) of desmoplakin ( red ) and -catenin ( green ) at distinct small junctional structures ( for details , see the review of moll et al .
2009 ) . bars 50 m double - label immunofluorescence laser - scanning microscopy images of cryostat cross sections through human lymph nodes , showing the specific , mutually exclusive localization of ve - cadherin in the endothelium of small blood vessels ( v ) and the desmoplakin and -catenin immunoreactions in the complexus adhaerentes of the endothelial and virgultar cells ( sevcs ) of the sinus ( s ) .
a colocalization of desmoplakin and ve - cadherin in the complexus adhaerentes of sevcs cells in the sinus ( s ) can be seen with special clarity in the yellow merged image ( ve - cadherin , red versus desmoplakin , green ) .
b corresponding merged image showing co - localization ( yellow ) of desmoplakin ( red ) and -catenin ( green ) at distinct small junctional structures ( for details , see the review of moll et al .
the list of special junctions summarized in this review is certainly not complete .
in particular , we have left out all those aj - like junctions that couple two apparently highly different cell types , i.e. , heterophilic or asymmetric junctions , simply because the two half - junctions might contain different molecular components from those in symmetric junctions .
( contactus adhaerentes ) , i.e. , highly specialized ajs that have been identified to connect the granular cells of the cerebellar glomeruli .
these aj - type plaque - bearing structures contain n - cadherin and m - cadherin ( rose et al .
interestingly , however , m - cadherin in these structures obviously does not seem to be essential for life , as abrogation of the gene encoding m - cadherin does not result in major defects but apparently is compensated by an upregulation of n - cadherin ( hollnagel et al .
thus , irrespective of the molecular organization in the m - cadherin - containing junctions , the special contribution of this glycoprotein to the function of the junction will have to be defined in comparison with n - cadherin .
therefore , although this review has in general to be considered incomplete , it serves primarily as a mind - opener indicating that further kinds of junctions may well lie just around the corner .
Output:
| immunocytochemical , electron- , and immunoelectron - microscopical studies have revealed that , in addition to the four major textbook categories of cell - cell junctions ( gap junctions , tight junctions , adherens junctions , and desmosomes ) , a broad range of other junctions exists , such as the tiny puncta adhaerentia minima , the taproot junctions ( manubria adhaerentia ) , the plakophilin-2-containing adherens junctions of mesenchymal or mesenchymally derived cell types including malignantly transformed cells , the composite junctions ( areae compositae ) of the mature mammalian myocardium , the cortex adhaerens of the eye lens , the interdesmosomal sandwich or stud junctions in the subapical layers of stratified epithelia and the tumors derived therefrom , and the complexus adhaerentes of the endothelial and virgultar cells of the lymph node sinus . on the basis of their sizes and shapes , other morphological criteria , and their specific molecular ensembles , these junctions and the genes that encode them
can not be subsumed under one of the major categories mentioned above but represent special structures in their own right , appear to serve special functions , and can give rise to specific pathological disorders . |
PubmedSumm6596 | ***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 recent years , advances in technology and healthcare have improved people s lives ; even so , fighting , conflicts , violence , and other traumatic phenomena , such as vehicle accidents , occupational accidents , and injuries sustained in the martial arts , have substantially intensified the physical damage that people can incur , such as oral and maxillofacial injuries ( 1 ) . at the present time ,
they cause morbidity and mortality , increase healthcare costs , and cause physical and functional deficits , such as interference with mastication , swallowing , speech , breathing , and interacting with others ; they also cause cosmetic problems , which , in turn , can cause psychological problems ( 2 , 3 ) .
there are different causes and mechanisms of traumas , and their effects can depend on the location on the body and the victim s age and gender ( 47 ) . in adults ,
the most common causes of such traumas worldwide are traffic accidents , violence , falls , and sports injuries ( 5 ) .
facial injuries as the result of trauma are divided to three main categories , i.e. , injuries to the facial bones , injuries to soft tissues , and dentoalveolar injuries ( 8) . the most important soft tissue injuries include lacerations , hematomas , contusions , and abrasions , with lacerations being the most common injuries to soft tissues caused by trauma ( 38% ) .
the most common age range of people who suffer soft tissue injuries is 030 ( 61.5% ) , and the most common causes of such injuries are daily activities ( 49.4 % ) and exercise ( 43.8 % ) ( 8 , 9 ) .
facial bone injuries include fractures of the lefort i , ii , iii , orbital , nasal , zygomatic , mandibular , and maxillary bones , and 58% of patients with fractured facial bones were 2040 years old .
common daily activities and occupational activities account for 28.7% of such fractures , and accidents account for 21.5% ( 8) .
these injuries can be either an isolated trauma ( involving only the face ) or a multiple trauma ( damage to multiple parts of the body ) , that can include limb , abdominal , intrathoracic , and intracranial injuries ( 10 ) .
in many countries , cranial injuries are the most common injuries in maxillofacial trauma patients , and with such injuries , patients can experience nausea , vomiting , loss of consciousness , and even coma ( 2 , 10 ) . in developing countries , such as iran ,
accidents are the most common etiology of injury , but , in developed countries , the trauma associated with accidents has been reduced significantly due to the use of seat belts in vehicles and the penalties for driving after drinking alcohol , so violence has become the most common etiology of injury .
traffic accidents are one of the most common causes of trauma , with 1.2 million people killed and 50 million others suffering morbidity each year .
the statistics in iran indicated that 27,567 people were killed and 276,762 were injured in traffic accidents in 1997 .
thus , the study of the causes , types , and severity of injuries in iran is very important ( 5 , 8) .
unfortunately , there are no specific organizations in iran that have the responsibility of recording the short- and long - term medical consequences of traffic accidents .
such information is recorded sporadically by the ministry of health , the ministry of labor , and others ( 6 ) . in patients admitted to hospitals with medical emergencies , acute and
life - threatening problems are dealt with first , and many other problems and injuries may be overlooked and diagnosed later , with the delayed diagnoses potentially causing irreparable problems . the purpose of this study was to investigate the prevalence and type of overlooked injuries that are associated with the ears , nose , and throat in patients with multiple traumas who are admitted to the shahid rahnamun hospital in yazd , iran , in 2012 and 2013 .
this retrospective study was conducted in multiple trauma patients who were admitted to the emergency department at shahid rahnamun hospital in 2012 and 2013 .
these patients were sent to ear , nose and throat ( ent ) department and given counseling .
however , 17 patients died , and seven others were sent to other healthcare facilities .
all of the patients with multiple traumas and a gcs score of less than 13 who were admitted to icu were given counseling and then sent to the ent department .
all patients with a gcs score greater than 13 and a gcs score less than 3 were excluded from the study .
those with gsc scores greater than 13 were excluded because of the areas of pain and injuries that were reported , and those with gsc scores less than 3 were excluded due to the likelihood that cerebral comas and lack of consciousness could occur .
demographic and etiology data of the main injury and the other associated injuries were obtained by studying the hospital s file for each of the patients , and the type , severity , and location of their injuries were determined by careful examination of the ears , nose , and throat .
this study was approved by the research committee of yazd medical university from a research ethics perspective .
among the 230 patients who were counseled by staff members of the ent department in 2012 and 2013 , 170 cases were related to trauma . among these
the mean interval between trauma and the diagnosis of associated injuries was 10 days , and the range was from three to 17 days .
the injuries were divided to two groups based on their etiologies that included five basic types , i.e. , accidents , violence , chores , occupation , and exercise , and the locations of the injuries , i.e. , soft tissue , bone , dentoalveolar , and neural injuries .
the most common etiology of injury was accidents , followed by violence , daily activities , occupation , and sports injuries .
in all cases of etiology , the injuries were more common in men ( p < 0.001 ) than in women . among the locations of the injuries , the most common were soft - tissue injuries , followed by bone , dentoalveolar , and facial nerve injuries ( table 1 ) .
undiagnosed injuries included nasal fractures ( 12 cases ) and septal hematomas ( 4 cases ) . at the time of diagnosis , the patients had necrosis , nasal cartilage , and saddle nose malformations .
twenty - four cases had posterior auricular lacerations and , due to the lack of diagnosis , severe infections .
one case required extended debridement , and two cases required locoregional flaps due to extended necrosis .
two cases had grade 6 facial paralysis ( complete paralysis ) that was , in both cases , due to a fractured longitudinal temporal bone that had not been diagnosed .
there were eight cases in which mandibular fractures had occurred , and , in four of those cases , granulation tissue was present in the line of fracture , the reduction of the fracture was not complete , and occlusion ( correct alignment of the teeth ) was not achieved .
these issues occurred due to the extensive time that passed after the injury with no medical intervention .
ten patients had varying degrees of intraoral lacerations ( oral lacerations ) in different areas , especially the lingual and buccal areas , which were due to the passage of time without any repair , resulting in severe infections that required extended debridement that produced malformations ( table 2 ) .
facial injuries are common in trauma , and they increase the risk of morbidity and mortality ( deaths ) due to physical - functional defects as well as mental disturbances in patients ; they also increase the cost of healthcare ( 2 , 3 ) .
the most common causes of trauma are accidents , violence , falls , daily activities , and exercise , but their incidences are different in different countries and at different ages ( 4 , 5 , 7 ) . in developing countries , due to the lack of preventive laws or failing to observe them , such as not fastening seat belts , traffic accidents are the most common cause of facial injuries ( 5 , 8) . in developed countries , due to the use of safety belts and observing the rules about not drinking alcohol while driving
, the trauma of traffic accidents has decreased in recent years , and violence has replaced traffic accidents as the most common etiology of injuries . in this study ,
the most common reasons for injuries were traffic accidents ( 63% ) , violence ( 13% ) , occupations and chores ( 9.2 % ) , and participating in sports activities ( 5.5% ) .
facial injuries have been classified as dentoalveolar , soft tissue , and bone injuries in various studies , most studies found that soft tissue injuries , especially lacerations , were the most common form of injury ( 811 ) . in the present study , 34 cases ( 62% ) of diagnosed injuries included soft tissue injury ( posterior auricular and oral laceration ) . due to the lack of attention during the oral examination of emergency patients ,
dentoalveolar injuries were overlooked , which resulted in patients suffering with complications as time passed and they became fully conscious ( 1215 ) .
this type of injury is more common in young people , and its incidence decreased by 4.5% with every year of increasing age ( 1621 ) .
seven patients had some degree of tooth fractures and six associated mandibular fractures were found among them .
therefore , in patients with tooth fractures due to trauma , the mandible also should be examined carefully to rule out a possible fracture .
facial bone fractures in trauma , especially trauma from accidents and daily activities , are common ( 8) . in children , the mandible is the most commonly - fractured facial ( 10 , 22 ) . in some studies ,
nasal bone fractures were the most common fractures of facial bones ( 9 ) , and , in some other studies , fractures of the orbital floor were the most common , followed by fractures of the zygomatic bone . in the present study , fractures of the nasal bone occurred in 22% of the cases , followed by fractures of the mandible at 14% . due to delayed diagnoses ,
four cases of nasal bone fractures were irreversible due to septal hematoma and nose cartilage necrosis that resulted from the lack of careful examination .
maxillofacial trauma was more common in males than in females by a ratio of 3 to 1 in most studies .
the most common age was older than 30 , and the common range was 2040 ( 60% of cases ) . in this study , 43 of the 54 patients who were diagnosed late were male ( p < 0.001 ) , and the age range was similar to that of previous studies ( 8 , 10 ) .
twenty - five percent of patients with facial injuries have associated injuries in other parts of the body , including abdominal , intrathoracic , limb , and intracranial injuries ( 10 ) . in most studies , the most common associated injuries , due to the proximity of skull to the face , were cranial injuries , particularly intracranial hemorrhages and skull base fractures ( 8 , 21 ) .
this , in turn , can decrease the level of consciousness and the patient s gcs . among the patients examined in this study , subarachnoid hemorrhage ( sah ) was the most common associated intracranial injury ( 80% ) , and it decreased the patients consciousness levels .
low consciousness , lack of patients complaining about associated problems , and lack of careful examinations led to delayed diagnoses after seeing various complications and after the patients consciousness levels improved . in a study of 54 patients with orbital floor fractures in turkey , the most common cause was traumatic violence , and most patients were diagnosed and underwent surgery between 696 hours after the trauma ; all patients were given thorough examinations and appropriate actions were taken within 96 hours ( 11 ) .
the reason this could be done was that the medical staff paid close attention to the patients clinical symptoms , such as enophthalmos and diplopia , and they used quick and timely coronal ct scans with fine ( 2 mm ) slices ( 11 ) . the approach of most studies in the case of facial trauma is to investigate the common types of facial injuries in trauma as well as the incidence and types of associated injuries ( 12 , 15 ) .
the fact that this study examined the case of undiagnosed facial injuries in unconscious trauma patients and investigated the type , incidence , and complications of such injuries in these patients differentiates it from other studies related to maxillofacial trauma .
full examinations upon admission and after the patients have been stabilized , daily serial examinations to detect signs of injury , early use of imaging , and consultation if suspicious symptoms are observed will help in the early diagnosis , treatment , and prevention of complications and problems that impose significant costs on the country s healthcare organizations . these activities also will eliminate ineffective and incomplete diagnoses that complicate the treatment process and cause irreparable problems for patients , including both physical and psychological damage .
the results of this study showed that the incidence of ent associated injuries is high in patients with multiple trauma .
overlooking such injuries intensifies the problem and causes complications , such as increased length of time in the hospital , increased risk of infection and mortality , and incomplete correction of side effects .
it is recommended that complete and thorough physical examinations be conducted for patients with multiple traumas after they are stabilized , a process that will require careful training of the medical staff and also careful and timely counseling .
Output:
| background : many trauma patients in the emergency department are unconscious , and this causes many other problems to go undiagnosed , resulting in the loss of valuable time in initiating the appropriate treatments .
the purpose of this study was to determine the prevalence and types of injuries to the ears , nose , and throat that are ignored in patients with multiple traumas in an emergency department.methods:this study was conducted by assessing patients with multiple traumas who were admitted to the emergency department at shahid rahnamun hospital in yazd , iran , in 2012 and 2013 , and who were advised to acquire diagnostic workups and treatment in the ear , nose , and throat department .
the patients data were gathered by studying their records and by careful examinations , and the data were analyzed using the chi - squared test by spss version 18.results:among the 230 patients who were counseled , 170 patients had multiple traumas that were caused by accidents , falls , conflicts between individuals , and natural disasters .
fifty - four patients with low glassco coma scale ( gcs ) values who were admitted to the icu were counseled after they regained consciousness . among the 54 cases , 12 cases ( 22% ) had nasal fractures and four cases had septal hematomas that resulted in infections and severe deformities .
twenty - four cases ( 44% ) had lacerations of posterior auricular components , one case required extended debridement , and two cases had extensive necrosis that required a local flap .
two cases ( 3% ) had paralyzed facial nerves , 8 cases ( 14% ) had fractured mandibles , and 10 cases ( 18% ) had laceration of the oral mucosa ( lingual - buccal ) that require extended debridement in the operating room.conclusions:it is recommended that complete physical examinations be done in patients with multiple trauma after they are stabilized ; such examinations would require careful training of the medical staff and also careful and timely counseling . |
PubmedSumm6597 | ***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: coexistence of hyperthyroidism and primary immune thrombocytopenia ( itp ) is a rather rare condition .
underlying untreated graves disease leads to worsening of the itp and rendering it refractory to standard therapy .
a 71-year - old female patient presented with a complaint of excessive sweating for nearly a month to a hematology unit where she had been followed - up with after a diagnosis of itp .
her laboratory tests revealed manifest hyperthyroidism in addition to thrombocytopenia , and hence she was referred to our endocrinology unit . on her physical examination , her pulse rate was 112 bpm , and her skin was warm and damp .
increased levels of anti - thyroid peroxidase , anti - thyroglobulin , and thyroid - stimulating antibody and enhanced uptake of radioactive iodine were observed , and the diagnosis of graves disease was confirmed .
methimazole therapy at daily doses of 30 mg was initiated . without any additional immunosuppressive treatment , at week 12 of methimazole therapy
, thyroid stimulating hormone ( tsh ) levels returned to normal , and platelet counts rose to tolerable levels .
when her hospital records were analyzed , they revealed that a year ago , when she had been diagnosed with itp , her tsh values had been suppressed . at that time
she had been given intravenous immune globulin ( 0.5 g / kg / day for 4 days ) and oral steroid ( 1 mg / kg / day ) for the treatment of itp .
the patient , whose platelet counts returned to being within normal limits , was followed - up with for 6 months . during this period ,
her platelet values were maintained at normal levels , and during her control visits , her tsh levels were measured twice and were within normal limits .
the patient 's laboratory test results are shown in chronological order [ table 1 ] .
afterwards , concomitancy of autoimmune thyroid diseases such as hashimoto thyroiditis and graves disease with itp has been reported many times . in graves disease ,
the lifespan of platelets is shortened significantly , and moderate degrees of thrombocytopenia are frequently seen . the potential mechanism involved in this process
the association between itp and graves disease is explained by immune dysregulation , which is the main mechanism underlying both diseases and involves an increase in the levels of antiplatelet and anti - thyroid antibodies in these patients . because of the strong fundamental autoimmune mechanism underlying both diseases , it is known that the treatment of associated autoimmune thyroid disorder contributes to the remission of itp .
it has been reported that the treatment of underlying graves disease in patients refractory to standard immunosuppressive therapy ensured remission of itp .
besides , only anti - thyroid treatment without additional immunosuppressive treatment enabled remission of itp . in our case ,
although spontaneous remissions can be seen in graves disease , we think that immunosuppressive therapy given for the treatment of itp - induced a transient euthyroidism in graves disease . during the 6 months following itp therapy of our patient ,
whose tsh values remained at normal levels , graves disease and concomitant itp recurrences were observed , and only anti - thyroid therapy increased platelet counts to tolerable levels .
it should be kept in mind that immunosuppressive therapy without considering thyroid function tests may result in a transient euthyroid state , which potentially masks graves disease accompanying immunosuppressive therapy and associated recurrent itp attacks .
Output:
| a 71-year - old female patient followed primary immune thrombocytopenia ( itp ) was admitted to endocrinology unit with excessive sweating .
we started methimazole for graves disease . without any additional immunosuppressive treatment , at week 12 of methimazole therapy
, thyroid stimulating hormone ( tsh ) levels returned to normal , and platelet counts rose to tolerable levels .
when her hospital records were analyzed , they revealed that a year ago , when she had been diagnosed with itp , her tsh values had been suppressed .
after immunosuppressive therapy , her platelet values were maintained at normal levels , and during her control visits , her tsh levels were measured twice and were within normal limits .
we think that immunosuppressive therapy for itp without considering thyroid function tests may result in a transient euthyroid state , which potentially masks graves disease accompanying immunosuppressive therapy and associated recurrent itp attacks . |
PubmedSumm6598 | ***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: fast neuronal network oscillations in the gamma frequency band ( 30100 hz ) that occur in the electroencephalogram or in local field potential recordings have been observed in virtually any mammalian cortical structure , including the neocortex and the hippocampus ( gray and singer , 1989 ; traub et al . , 1996 ; buzski and draguhn , 2004 ; bartos et al .
gamma oscillations reflect synchronous membrane potential oscillations of a large number of neurons in a given neuronal network , and they have been suggested to underlie higher cognitive functions such as sensual perception , attention , and memory formation ( lisman , 1999 ; axmacher et al . , 2006 ; mann and paulsen , 2007 ; uhlhaas and singer , 2010 ) .
gamma oscillations are generated in local neuronal networks by the complex interplay of excitatory neurons and specific inhibitory interneurons , both of which communicating via chemical and , perhaps , electrical synapses ( tams et al .
, 2000 ; whittington and traub , 2003 ; bartos et al . , 2007 ) . functionally , gamma oscillations bind neurons into a common temporal matrix , enabling precise temporal coding , spike timing - dependent plasticity , and formation of neuronal assemblies ( paulsen and moser , 1998 ; engel and singer , 2001 ; buzski and draguhn , 2004 ; axmacher et al . , 2006 ) .
a characteristic feature is the long - range synchronization of gamma oscillations in remote cortical areas ( knig et al . , 1995 ; bazhenov et al . ,
this phenomenon has been suggested to underlie binding of distributed neuronal representations and , therefore , forms a crucial neuronal prerequisite for the unity of sensual perception , attention , and , perhaps , consciousness ( engel and singer , 2001 ; fries et al .
importantly , gamma oscillations can be reliably induced in brain slice preparations in vitro ( see below ) .
the human brain consumes about 20% of the oxygen inspired at rest while accounting for only 2% of the body weight ( erecinska and silver , 2001 ) .
this suggests that neuronal information processing is associated with an extraordinary high metabolic rate . in more global estimations ,
most of the energy consumption has been attributed to action potential generation ( spiking ) and excitatory synaptic transmission ( attwell and laughlin , 2001 ) .
however , information about the energy demands of different functional brain states , i.e. , the energy demands of different forms of neuronal network activity , is widely lacking ( kann and kovcs , 2007 ; cunningham and chinnery , 2011 ) . from the clinical medicine point of view , higher cognitive functions appear to be exceptionally vulnerable during various neurological and psychiatric brain pathologies ( hansen , 1985 ; mcfarland et al . , 2010 ; uhlhaas and singer , 2010 ) .
therefore , impairment of energy metabolism by either alterations in oxygen and nutrients supply and/or dysfunction of neuronal mitochondria might be a key pathogenic factor ( kann and kovcs , 2007 ; dimauro and schon , 2008 ; distelmaier et al .
, 2009 ; nicholls , 2009 ; wallace , 2010 ) . strikingly , neuroenergetical aspects such as energy consumption and adaptations of energy metabolism that are associated with different forms of neuronal network activity have been less defined : gamma oscillations as a cellular correlate of higher cognitive functions are a prime example ( axmacher et al . , 2006 ; uhlhaas and singer , 2010 ; cunningham and chinnery , 2011 ) .
this lack of information is mainly caused by technical limitations , ( i ) in the accessibility to certain cortical areas , and ( ii ) in the high spatiotemporal resolution that is required for simultaneous local recordings of neuronal activity and energy metabolism at the level of mitochondria in vivo ( kann and kovcs , 2007 ; cunningham and chinnery , 2011 ) .
in the recent years , research has thus focused on brain slice preparations , in particular from the hippocampus , to address the energy demand of gamma oscillations and the associated adaptations in energy metabolism in vitro .
here , i will firstly describe the features of hippocampal slice preparations as a reliable model to study both , gamma oscillations and neuroenergetics , and secondly review recent reports from various groups in the field .
these reports suggest that gamma oscillations are associated with high energy demand that is counterbalanced by rapid adaptations in oxidative energy metabolism .
living slice preparations have been successfully made from the neocortex and the hippocampus of both , rodents and humans ( mcilwain , 1951 ; schwartzkroin and andersen , 1975 ; fisahn et al . , 1998 ; kann et al .
, 2005 ; vreugdenhil and toescu , 2005 ; ivanov et al . , 2011 ) .
hippocampal tissue is usually cut in slices with a thickness of 300400 m . to minimize ischemic neuronal damage because of arrest in blood circulation ,
the preparation of slices is carried out quickly and in cold preparation solution that contains ion concentrations similar to the cerebrospinal fluid in vivo ( bischofberger et al . , 2006 ; kann and kovcs , 2007 ; hjos and mody , 2009 ) .
recently , the add - on of further important substrates and nutrients has been proposed ( hjos and mody , 2009 ; zilberter et al . , 2010 ) .
notably , for investigations of hippocampal slices much higher glucose concentrations ( 1026 mm ) have been used compared with the brain in vivo ( 0.352.6 mm ) because it is difficult to obtain healthy slices using lower concentrations ( kann and kovcs , 2007 ) .
oxygenation and ph adjustment of preparation solution is achieved by a gas mixture of 95% o2 and 5% co2 .
the high oxygen fraction is routinely used to ensure sufficient oxygen supply of healthy neurons in deeper slice layers , which ultimately depends on a steep diffusion gradient .
monitoring the interstitial partial oxygen pressure ( po2 ) with oxygen sensor microelectrodes in hippocampal slices during spontaneous neuronal activity revealed that oxygen was still available in excess ( po2 > 150 mmhg ) at the depth of 160 m below the slice cut surface ( kann et al . , 2011 ) .
however , the po2 at the slice cut surface is often lower than theoretically expected and might significantly vary in experimental studies because of individual experimental settings such as size and construction of the recording chamber , temperature , as well as exchange rate of gas mixture or recording solution .
notably , the po2 is not monitored routinely in many studies because oxygen is provided in excess , at least in the neuronal cell layers of the upper third of the slice where electrophysiological and live - cell fluorescence imaging recordings are conducted ( kann and kovcs , 2007 ) .
after preparation , hippocampal slices are either used for experiments in the next 1012 h ( acutely prepared slices ; mcilwain , 1951 ; schwartzkroin and andersen , 1975 ) or maintained under sterile conditions on a biopore membrane in an incubator for up to weeks ( organotypic slice cultures ; stoppini et al . ,
it is important to note that individual neurons and neuronal networks in such slice cultures show similar morphological and functional features as compared to the hippocampus in vivo ( caeser and aertsen , 1991 ; bahr et al . , 1995 ; de simoni et al . , 2003
; kann et al . , 2011 ) , including preservation of the natural cellular environment , i.e. , the presence of astrocytes and microglial cells ( organotypic ) . however , hippocampal slice cultures widely lack input from other ( sub)cortical brain areas .
after 1014 days in vitro slice cultures have shorter diffusion distances for oxygen and nutrients compared to acutely prepared slices because of the residual thickness of about 200 m . moreover , the initially damaged slice cut surface is reorganized ( bahr et al . , 1995 ; kann and kovcs , 2007 ) .
during electrophysiological and/or live - cell fluorescence imaging recordings slice preparations are stored either entirely in recording solution that is saturated with the gas mixture containing 95% o2 ( submerged condition ) or at the interface between recording solution and the gas mixture ( interface condition ; kann and kovcs , 2007 ; hjos and mody , 2009 ) . under the interface condition ,
usage of brain slice preparations has significantly contributed to a deeper understanding of neuronal functions at the cellular and network level in the recent decades .
however , given factors such as absence of blood circulation , longer diffusion distances , steep interstitial po2 gradients , and composition of the recording solution have to be kept in mind when interpreting data from slice preparations ( kann and kovcs , 2007 ; zilberter et al . , 2010 ) .
in neuronal networks of the hippocampus , pyramidal cells , and granule cells are excitatory projection neurons with long - range glutamatergic connections ( releasing neurotransmitter , glutamate ) .
besides these projection neurons there is a population of various inhibitory gabaergic interneurons [ releasing neurotransmitter , -aminobutyric acid ( gaba ) ] , comprising about 10% of all hippocampal neurons ( caeser and aertsen , 1991 ; freund and buzki , 1996 ; freund , 2003 ) . evidence from electrophysiological recordings , high - resolution functional imaging , transgenic animals , and mathematical modeling has revealed a major role of these inhibitory interneurons in the generation of coherent activity patterns .
specific types of interneurons support broad simultaneous rhythmic inhibition and thus synchronize the activity of large neuronal populations in vitro and in vivo ( freund , 2003 ; whittington and traub , 2003 ; bartos et al . , 2007 ;
perisomatic gabaergic interneurons are of central importance because the highly divergent axonal plexus allows synchronous inhibition of 10002000 pyramidal cells ( freund and buzki , 1996 ; freund , 2003 ; mann and paulsen , 2007 ) .
about 50% of these interneurons are parvalbumin - containing baskets cells that are able to generate fast series of action potentials and , thus , follow almost every gamma cycle ( 30100 hz ) .
pyramidal cells , by contrast , show strong spiking accommodation and have typical spiking rates around 24 hz during gamma oscillations in vitro and in vivo ( csicsvari et al . , 1999 ; freund , 2003 ; hjos et al . , 2004 ; gulys et al . ,
it is important to note that the rhythmic hippocampal oscillations that occur in local field potential recordings in vitro primarily reflect averaged synchronized inhibitory postsynaptic potentials ( ipsps ) in the perisomatic region rather than action potentials and excitatory postsynaptic potentials ( epsps ; mann et al . , 2005 ; oren et al . , 2010 )
similar findings were reported from slices of the occipital cortex ( trevelyan , 2009 ) . sustained gamma oscillations can be reliably induced in both , acutely prepared slices and slice cultures . in most of the studies ,
low concentrations of acetylcholine ( carbachol ) or kainic acid were added to the recording solution to activate muscarinic and ionotropic glutamate receptors , respectively ( fisahn et al .
, 1998 ; fellous and sejnowski , 2000 ; vreugdenhil and toescu , 2005 ; wjtowicz et al . , 2009 ; kann et al . , 2011 ) .
in particular , application of acetylcholine mimics cholinergic input from the septum in vivo . despite some differences in the underlying synaptic mechanisms ( bartos et al . , 2007 )
both models share important features with hippocampal gamma oscillations in vivo and are commonly used for analysis and mathematical modeling of cellular and network dynamics ( whittington and traub , 2003 ; bartos et al . , 2007 ; hjos and paulsen , 2009 ) . in hippocampal slice preparations ,
pharmacologically induced sustained gamma oscillations occur most prominently in subfield ca3 and weaker in subfield ca1 , and they are absent in the dentate gyrus .
this has been observed in both acutely prepared slices and slice cultures from mouse and rat ( fisahn et al . , 1998 ;
the oscillations are widely similar to gamma oscillations in vivo , including the sites of intrahippocampal generation and propagation .
one exception is that under certain conditions input from the entorhinal cortex might also drive gamma oscillations of lower power in the dentate gyrus in vivo ( csicsvari et al . , 2003 ) .
gamma oscillations in vivo occur in the presence and the absence of theta oscillations ( 69 hz ) , in brief periods as well as prolonged periods ( > 10 s ) during running of the animal or rapid - eye - movement ( rem ) sleep ( penttonen et al .
, 1998 ; buhl et al . , 2003 ; buzski et al . , 2003 ; chen et al .
gamma oscillations in vitro have been reliably induced in the interface recording condition ( traub et al . , 1996 ; fisahn et al . , 1998 ) .
notably , under the submerged recording condition gamma oscillations could be only induced when the exchange of recording solution was significantly improved , for example by increasing the flow rate to 56 ml / min and by decreasing the volume of the recording chamber ( hjos et al . , 2004 ; huchzermeyer et al . , 2008
further studies demonstrated rapid decreases in the power of gamma oscillations in hippocampal slice preparations , ( i ) when the po2 of the ambient atmosphere was lowered to the normoxic range under the interface recording condition ( huchzermeyer et al . , 2008 ) ,
( ii ) when the flow rate of oxygenated recording solution was too low under the submerged recording condition ( hjos et al . ,
2009 ) , and ( iii ) when hypoxic events were induced ( fano et al . , 2007 ; pietersen et al . , 2009 ) .
rapid decreases in the power of gamma oscillations were also observed during pharmacological interference with mitochondrial function , namely inhibition of the respiratory chain by rotenone ( acting on complex i ) or potassium cyanide ( acting on cytochrome c oxidase in complex iv ) , and mitochondrial uncoupling by protonophores ( kann et al . , 2011 ; whittaker et al . , 2011 ) .
moreover , the exquisite sensitivity of gamma oscillations to mitochondrial dysfunction has been identified because other activity forms such as electrical stimulus - evoked neuronal activation and pathological seizure - like events were more resistant to both , respiratory chain inhibition and low po2 ( huchzermeyer et al . , 2008 ; kann et al . , 2011 ) .
similar observations were recently made during unilateral hippocampal ischemia in vivo ( barth and mody , 2011 ) .
these studies consistently show that hippocampal gamma oscillations are rapidly impaired during metabolic stress , indirectly suggestive for a high energy demand .
mechanistically , fast - spiking inhibitory interneurons might play a crucial role in this rapid impairment because of their key role for establishment of gamma oscillations as well as the unique electrophysiological and biochemical properties when compared to excitatory projection neurons ( gulys et al .
, 2006 ; alle et al . , 2009 ; carter and bean , 2009 ; hasenstaub et al . , 2010 ; kann et al . , 2011 ; whittaker et al . ,
more direct evidence for the high energy demand of gamma oscillations was recently provided by combining local field potential and po2 recordings .
it was demonstrated that the power of gamma oscillations positively correlated with a substantial increase in oxygen consumption in both , acutely prepared slices and slice cultures .
intriguingly , the level of oxygen consumption as determined during gamma oscillations reached the level that was observed during a strong pathological form of neuronal activity , namely seizure - like events ( kann et al . , 2011 ) . these data clearly substantiate the notion that hippocampal gamma oscillations in vitro are associated with high oxygen consumption .
this is in line with an in vivo study from the cat visual cortex describing tight correlations between gamma oscillations and hemodynamic responses ( niessing et al . , 2005 )
that might reflect local adaptations in blood flow to increase oxygen and nutrients supply ( leybaert , 2005 ; attwell et al .
the high oxygen consumption during gamma oscillations might be explained by several mechanisms underlying neuronal signaling .
both , excitatory pyramidal cells and inhibitory gabaergic interneurons increase their spiking rates from different base levels during gamma oscillations .
this would increase the energy demand in these neurons , despite the fact that diverse neuronal subtypes might feature different biophysical properties for energy cost efficient generation of action potentials ( hasenstaub et al . , 2010 ) . as a consequence of increased spiking rates and highly divergent connectivity , and
this might be more relevant for the increased energy demand during gamma oscillations , the incidence of epsps and ipsps in the neuronal network massively increases , and thus ion fluxes through neuronal membranes as well ( de simoni et al . , 2003 ; whittington and traub , 2003 ; mann and paulsen , 2007 ) .
the ion fluxes tend to dissipate the concentration gradients of na , ca , k , and cl ions that exist across neuronal membranes to ensure proper neuronal function . in order to maintain ionic homeostasis ,
the concentration gradients are continuously reconstituted against electrochemical equilibrium by ion pumps such as na / k - atpase and ca - atpase as well as transporters such as na / ca - exchanger and na / k / cl - cotransporter .
these transport processes are finally energy - dependent , leading to breakdown of cellular energy carrier , atp ( attwell and iadecola , 2002 ; kann and kovcs , 2007 ) . in the brain ,
most of the atp generation has been attributed to oxidative phosphorylation in mitochondria ( erecinska and silver , 2001 ; attwell and iadecola , 2002 ) and neurometabolic coupling is rapidly mediated by changes in substrate ratios as well as cytosolic and mitochondrial ca - signaling ( duchen , 1992 ; kann et al . , 2003 ; leybaert , 2005 ; kann and kovcs , 2007 ) .
therefore , the high oxygen consumption as observed during gamma oscillations might reflect fast adaptations in mitochondrial oxidative energy metabolism .
however , further experimental studies are required to determine the potential contribution of energy substrates other than glucose as well as the roles of aerobic and anaerobic glycolysis ( magistretti and pellerin , 1999 ; raichle and mintun , 2006 ; schurr , 2006 ; schousboe et al .
in several reports , live - cell fluorescence imaging of nicotinamide adenine dinucleotide ( phosphate ) and flavin adenine dinucleotide [ nad(p)h , fad ] was applied to get insight into neuronal activity - dependent changes in mitochondrial redox state , and thus adaptations in energy metabolism ( duchen , 1992 ; kann et al . , 2003 ;
using this imaging technique the changes in mitochondrial redox state during gamma oscillations were recently investigated in slice cultures .
interestingly , gamma oscillations were associated with a shift toward reduction of the dinucleotides although the interstitial po2 was hyperoxic ( huchzermeyer et al . , 2008 ) .
this observation might reflect an increase in the availability of substrates as a result of enhanced glycolysis in neuronal and astrocytic compartments ( kasischke et al .
, 2004 ; brennan et al . , 2006 ; hertz et al . , 2007 ) or an imbalance of neuronal tricarboxylic acid cycle and mitochondrial respiratory chain activities .
moreover , repetitive electrical stimulation that was additionally applied during gamma oscillations resulted in significantly smaller shifts toward oxidation of the dinucleotides compared to controls ( kann et al . ,
these data suggest that hippocampal gamma oscillations are associated with near - limit utilization of mitochondrial oxidative capacity , and thus provide further evidence for the high energy demand during gamma oscillations .
the data might also imply that rapid and sufficient supply of oxygen and nutrients is a fundamental prerequisite for the maintenance of fast neuronal network oscillations .
intriguingly , the electrophysiological and biochemical features of hippocampal subfield ca3 , namely highest levels in gamma oscillation power , oxygen consumption , and mitochondrial performance , also correlated with the highest expression of mitochondrial complex i subunits ( kann et al . , 2011 ; wirtz and schuelke , 2011 ) .
complex i ( nadh : ubiquinone oxidoreductase ) is part of the mitochondrial respiratory chain and composed of up to 46 individual subunits .
these subunits are encoded by both , nuclear and mitochondrial dna ( distelmaier et al . , 2009 ) .
mitochondrial complex i has been discussed to exert major control over oxidative phosphorylation , and to play a key role in the pathogenesis of neurodegenerative diseases ( pathak and davey , 2008 ) .
the pattern of complex i gene expression in the hippocampus might reflect unique enzymatic properties of neuronal mitochondria in subfield ca3 to match the high energy demand that is associated with the generation of gamma oscillations ( kann et al . , 2011 ) .
it has been known from animals and humans that higher sensory and motor functions are much more vulnerable to metabolic stress than basic responses of neurons to extrinsic electrical stimuli and ion distributions in neuronal tissue ( rossen et al . , 1943 ; hossmann and sato , 1970 ; hansen , 1985 ) . however , the underlying cellular mechanisms are still unknown .
gamma oscillations have been discussed as a cellular correlate of higher cognitive functions ( lisman , 1999 ; axmacher et al . , 2006 ; mann and paulsen , 2007 ; uhlhaas and singer , 2010 ) .
thus , the recent neuroenergetical data on gamma oscillations in brain slice preparations and the proposed mechanisms as outlined above might contribute to a more comprehensive understanding of the exceptional vulnerability of higher brain functions during circulatory disturbances , mitochondrial diseases , and neurodegeneration .
the author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest .
epsp , excitatory postsynaptic potential ; fad , flavin adenine dinucleotide ; gaba , -aminobutyric acid ; ipsp , inhibitory postsynaptic potential ; nad(p)h , nicotinamide adenine dinucleotide ( phosphate ) ; po2 , partial oxygen pressure .
Output:
| fast neuronal network oscillations in the gamma range ( 30100 hz ) in the cerebral cortex have been implicated in higher cognitive functions such as sensual perception , working memory , and , perhaps , consciousness . however
, little is known about the energy demand of gamma oscillations .
this is mainly caused by technical limitations that are associated with simultaneous recordings of neuronal activity and energy metabolism in small neuronal networks and at the level of mitochondria in vivo .
thus recent studies have focused on brain slice preparations to address the energy demand of gamma oscillations in vitro . here , reports will be summarized and discussed that combined electrophysiological recordings , oxygen sensor microelectrodes , and live - cell fluorescence imaging in acutely prepared slices and organotypic slice cultures of the hippocampus from both , mouse and rat .
these reports consistently show that gamma oscillations can be reliably induced in hippocampal slice preparations by different pharmacological tools .
they suggest that gamma oscillations are associated with high energy demand , requiring both rapid adaptation of oxidative energy metabolism and sufficient supply with oxygen and nutrients . these findings might help to explain the exceptional vulnerability of higher cognitive functions during pathological processes of the brain , such as circulatory disturbances , genetic mitochondrial diseases , and neurodegeneration . |
PubmedSumm6599 | ***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 57-year - old woman presented with a three - day history of photophobia and diplopia in the left eye .
she was diagnosed with histologically confirmed nasal nktl of the right nasal cavity one month prior .
the snellen visual acuity of the affected eye with correction was 1.0 / 0.63 , and the intraocular pressure in the right and left eyes was 17 and 18 mmhg , respectively .
the patient had mild left eye conjunctival injection , ptosis , and swelling of the eyelid .
opthalmoplegia , vitreous opacity , and an iris mass developed in the left eye ( fig .
thirty - five percent of the cells obtained from the aspiration were morphologically atypical lymphocytes .
skin biopsy confirmed neoplastic infiltration of small- to medium - sized pleomorphic lymphocytes with irregular nuclei , inconspicuous nucleoli , and scant cytoplasm ( fig .
immunohistochemical staining was positive for cd56 ( fig . 2c ) and cd3 ( fig .
the patient was diagnosed with nasal nktl with ocular involvement . after receiving radiotherapy at 900 cgy ,
her visual acuity improved and her anterior uveitis , vitreous opacity , and iris mass resolved ( fig .
3a and 3b ) . however , the patient 's condition continued to deteriorate despite radiotherapy and chemotherapy , and her ptosis and ophthalmoplegia gradually progressed .
extranodal nktl , including nasal nktl , previously known as lethal midline granuloma , is a definitive diagnostic entity according to the world health organization lymphoma classification .
however , histopathologically identical tumors may be identified at other extranodal sites , including the skin , muscle , gastrointestinal tract , liver , kidney , and retroperitoneal space .
did report a case of histologically confirmed nasal nktl with intraocular involvement , however , in most cases intraocular involvement has not been confirmed histologically .
the presence of intraocular involvement raises the possibility of leptomeningeal or central nervous system dissemination , and prompts consideration for external - beam radiotherapy to the eye and orbit in addition to systemic chemotherapy .
nktl involving the ocular adnexa is generally a rapidly progressing disease , with a short survival from time of diagnosis , despite standard therapy .
this was true in the current case as well ; the patient died three months after diagnosis .
since nktl with ocular and orbital involvement is very rare and is characterized by rapid disease progression and a poor prognosis , nktl should be considered in the differential diagnosis of uveitis or orbital pseudotumor refractory to therapy .
Output:
| herein , we report a case of nasal natural killer t - cell lymphoma ( nktl ) with intraocular involvement . a 57-year - old woman was referred due to a three - day history of photophobia and diplopia in the left eye .
one - month previously , she was diagnosed with nasal nktl of the right nasal cavity .
ophthalmic examination revealed conjunctival injection and ptosis .
the left pupil was fully dilated and non - reactive to light .
ocular motion was restricted on left - upper gaze .
five days later , anterior uveitis developed and persisted despite topical steroid treatment .
an orbital magnetic resonance imaging was without specific findings , however , ophthalmoplegia , vitreous opacity , and an iris mass were observed .
a diagnostic anterior chamber aspiration was performed .
aqueous humor aspiration revealed 35% morphologically atypical lymphocytes .
after an intravitreal triamcinolone injection , radiotherapy and chemotherapy were administered ; this resolved the uveitis and iris mass .
when refractory uveitis or orbital pseudotumor occurs in patients with nasal nktl , ocular and orbital involvement of the nktl should be considered . |
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