Question:
You will be presented with the full text of a biomedical research paper. Please write an abstract for this paper. Your response should include the abstract and no additional text.

Paper text:
blunt traumatic infrarenal aortic injuries are rare , with a few case reports in the literature .
a more common occurrence is an intimal flap which may form after blunt injury to the aorta , and most of these will resolve with anticoagulation alone [ 1 , 2 ] .
blunt aortic injury which initially presents as an intimal flap ( grade i ) may progress and evolve into an intramural hematoma ( grade ii ) or a pseudoaneurysm ( grade iii ) .
aortic intimal flap progressing to dissection or pseudoaneurysm is an occurrence identified in 2% or less of the patients , and the majority of these occur in the thoracic aorta [ 1 , 2 ] .
this article presents the case of a young woman found to have an intimal flap in the infrarenal abdominal aorta after a car accident , and the injury progressed to a pseudoaneurysm over 3 months .
a 47-year - old woman with a history of hypertension and smoking was involved in a  high - speed motor vehicle accident and presented to the emergency department with back pain .
computed tomographic ( ct ) scans were obtained of her abdomen and pelvis . on a single image from the abdominal scan ,
what appeared to be either an intimal flap or a small amount of contrast extravasation outside of the infrarenal aorta could be seen .
her care providers had differing opinions as to what was being seen on the image .
since the abnormality was only seen on a single image , the exact etiology could not be delineated ( fig .
the patient was observed in the hospital overnight , had minimal complaints the next day , and was discharged on aspirin .

figure 1:initial ct scan shows enhancing vascular abnormality on the right side of the aorta , shown by the black arrow .
initial ct scan shows enhancing vascular abnormality on the right side of the aorta , shown by the black arrow .
a follow - up ct scan was obtained 3 months later . at the location of the previous aortic abnormality
, there was a 3    1  cm pseudoaneurysm that had formed and could now be clearly seen ( figs 2 and 3 ) .
figure 2:pseudoaneurysm now clearly seen 3 months later .
 figure 3:black arrow pointing to pseudoaneurysm with enhancing flow outside of the aortic lumen .
operative repair was recommended , but the patient s aorta measured only 18  mm at the aortic bifurcation and was too small for even the smallest endovascular stent graft available at our institution .
therefore , an open replacement of her infrarenal aorta was performed using a dacron 22  mm graft . in the operating room ,
after the aorta was clamped and opened , a 4  mm tear in the intima had formed a mature channel into the pseudoaneurysm .
the patient recovered very well and was discharged from the hospital without complications . at her
2-year follow - up , she was in good health and had no further problems , but continues to smoke .
blunt abdominal aortic trauma occurs in only 0.040.1% of all nonpenetrating traumas [ 3 , 4 ] . and
the vast majority of these ( 92% ) are associated with multiple other injuries [ 3 , 5 ] .
our patient had no other injuries , and there was no retroperitoneal hematoma or other signs of vascular injury in the area , as is usually seen on ct when the aorta is injured [ 35 ] .
the lack of other radiographic traumatic findings added to the initial confusion as to whether there was a true injury to the aorta , or if the single image was showing artifact or an enlarged vertebral vessel .
since the majority of intimal flaps heal with anticoagulation alone ( 55% ) or remain stable ( 40% ) , a conservative plan including daily aspirin and re - imaging in 3 months was chosen . when repeat imaging showed a 3  cm pseudoaneurysm , operative repair was necessary .
endovascular repair was initially chosen for this case , but after measuring the patient s aorta , femoral vessels and the degree of taper at the bifurcation , there was not an appropriate endovascular prosthesis available in such a small size .
only one study has compared conventional open repair with endovascular repair for blunt injuries of the abdominal aorta and found similar results in both groups .
endovascular repair is generally favored since the injuries tend to be focal and discrete , making them quite amenable to a short graft .
further , the patients usually have other significant injuries that would complicate a long , and potentially morbid , open operation on the aorta .
although all blunt infrarenal aortic injuries are unusual , most of them consist of intimal flaps or dissections [ 3 , 58 ] .
a post - traumatic pseudoaneurysm , as this patient had , is even more unusual after blunt trauma .
one prior publication did document the delayed occurrence of a post - traumatic infrarenal aortic pseudoaneurysm that was diagnosed 3 years after injury .
endovascular repair for pseudoaneurysms must include post - procedure angiography to document no evidence of a type i or type ii endoleak , which could allow filling of the aneurysm sac and later rupture .
this case report highlights the need for delayed imaging for even minor intimal flaps or small aortic injuries after trauma , since progression does occur .
while the vast majority of these injuries improve over time or remain stable , a small percentage will worsen and require intervention .

Answer:
blunt traumatic infrarenal aortic injuries are unusual , and the formation of a delayed pseudoaneurysm of the aorta is even more rare . in this report
 , a young woman developed a small intimal flap of the infrarenal aorta after a motor vehicle accident which progressed into a 3  cm pseudoaneurysm after 3 months .
 operative repair was successful and the patient recovered .
 this case illustrates the importance of repeat imaging of small blunt aortic injuries since progression can occur .


Question:
You will be presented with the full text of a biomedical research paper. Please write an abstract for this paper. Your response should include the abstract and no additional text.

Paper text:
we assembled snp array data from 29,589 unrelated people and 222 nuclear families genotyped at 490,000910,000 snps from the candidate gene association resource ( care ) , studies at the children s hospital of philadelphia ( chop ) , the african american breast cancer consortium , the african american prostate cancer consortium and the african american lung cancer consortium . to build a recombination map , we used hapmix to localize candidate crossover positions , and implemented a markov chain monte carlo ( mcmc ) that used the probability distributions for the positions of the filtered crossovers to infer recombination rates for each of 1.3 million inter - snp intervals .
we also implemented a second mcmc that models each individual s set of crossovers as a mixture of a shared ( s ) map similar to the european decode map and an african - enriched ( ae ) map , and then assigns each individual an  ae phenotype  corresponding to the proportion of their newly detected crossovers assigned to the ae map .
we imputed genotypes at up to three million hapmap2 snps using mach , and then tested each of these snps for association with the ae phenotype and other recombination - related phenotypes .
we identified 2,454 candidate african - enriched hotspots with increased recombination rates in the yri vs. ceu maps , and in the ae vs. s maps , and searched for motifs enriched at these loci , thus identifying a degenerate 17-bp motif . to study the structure of prdm9 ,
we measured the length of the prdm9 zinc finger array and genotyped rs6889665 in yri , ceu and the care nuclear families ; we also carried out imputation based on 1000 genomes project short read data to infer the alleles individuals carry , among 29 previously characterized in a sequencing study of prdm9 .

Answer:
recombination , together with mutation , is the ultimate source of genetic variation in populations .
 we leverage the recent mixture of people of african and european ancestry in the americas to build a genetic map measuring the probability of crossing - over at each position in the genome , based on about 2.1 million crossovers in 30,000 unrelated african americans . at intervals of more than three megabases
 it is nearly identical to a map built in europeans . at finer scales it differs significantly , and we identify about 2,500 recombination hotspots that are active in people of west african ancestry but nearly inactive in europeans .
 the probability of a crossover at these hotspots is almost fully controlled by the alleles an individual carries at prdm9 ( p<10245 ) .
 we identify a 17 base pair dna sequence motif that is enriched in these hotspots , and is an excellent match to the predicted binding target of african - enriched alleles of prdm9 .


Question:
You will be presented with the full text of a biomedical research paper. Please write an abstract for this paper. Your response should include the abstract and no additional text.

Paper text:
bariatric surgery has become an effective treatment for obesity , also reducing the onset of type 2 diabetes mellitus ( t2 dm )   as well as inducing remission   and reducing cardiovascular mortality and mortality in general [ 3 , 4 ] .
obesity is a chronic condition characterized by elevated inflammatory markers [ 57 ] and is associated with nonalcoholic fatty liver disease ( nafld ) [ 8 , 9 ] .
serum gamma - glutamyltransferase ( ggt ) and alanine aminotransferase ( alt ) are markers of nafld and of liver fat content [ 10 , 11 ] .
increased platelet counts have been observed in conditions with chronic inflammation as well as in obesity , probably due to secondary thrombocytosis [ 1214 ] . in more advanced stages of nafld , with portal hypertension and splenomegaly ,
there is a linear association between decreased platelet counts and increased fibrosis in the histopathology of liver biopsies , which may indicate that platelet counts might be an important biomarker of the degree of fibrosis in nafld patients .
platelet count is a simple , easy to perform , cost - effective , and accurate surrogate marker for predicting fibrosis severity in nafld patients .
bariatric surgery improves steatosis and fibrosis in patients with morbid obesity nafld , and adjustable gastric banding in a previous study has been related to a nonsignificant trend of lowered platelet counts .
regarding rygbp , one study reports a significant reduction in platelet counts 1 year after surgery .
data after longer periods of followup , after rygbp as well as bpd - ds surgeries , are lacking .
the aim of this study was to assess changes , if any , in morbidly obese patients treated with bpd - ds and rygbp , from baseline , that is , before surgery , to followups 1 year and 3 years after surgery , with regard to platelet counts and serum concentrations of ggt and alt .
ten morbidly obese patients who had undergone bpd - ds surgery ( five men and five women ) , all caucasians , free from established diabetes , were recruited from the outpatient clinic of obesity care , uppsala university hospital , uppsala , sweden .
data from the bpd - ds group were compared to that of a morbidly obese group ( n = 21 ; three men and eighteen women ) , all free from established diabetes and had undergone rygbp .
patients were investigated preoperatively ( baseline ) and then 1 year ( 1st followup ) and 3 years ( 2nd followup ) after bpd - ds and rygbp , respectively .
roux - en - y gastric bypass is a procedure that combines restriction and malabsorption .
it is considered by many to be the gold standard because of its high level of effectiveness and its durability .
more extreme malabsorption accompanies biliopancreatic diversion procedures , commonly performed with a duodenal switch in which a short , distal and common channel length of small intestine severely limits caloric absorption , which induces a greater weight loss than rygbp does .
a very high bmi indicated that bpd - ds procedure was performed instead of rygbp at our clinic [ 19 , 20 ] .
all participants underwent physical examination and blood tests for platelet count , ggt , and alt preoperatively ( baseline ) and at the 1st and 2nd followups .
blood samples were collected from each patient ( following an overnight fast ) and were analyzed using routine tests at the department of clinical chemistry at uppsala university hospital [ 19 , 20 ] . weight ( kg ) and height ( m ) were measured on standardized calibrated scales , and bmi ( kg / m ) was calculated .
tests were two tailed , and a p  value < 0.05 was considered significant .
patient clinical characteristics at baseline , that is , before rygbp and bpd - ds surgeries , are shown in table 1 .
there were no statistically significant intergroup differences in platelet counts or plasma concentrations of ggt and alt .
mean weight and bmi were , as expected , higher in the bpd - ds group , selecting the patients for this procedure , and age was lower .
bmi decreased by 43% in the bpd - ds group from 53.5  kg / m at baseline to 30.7  kg / m at 1st followup ( p < 0.001 ) and was unchanged between the 1st and 2nd followups ( 30.2  kg / m ,  p < 0.001 ) , as shown in figure 1(a ) . in the rygbp group ,
bmi was reduced by 30% from 42.3  kg / m at baseline to 29.7  kg / m at the 1st followup ( p < 0.001 ) but was 32.1  kg / m at the 2nd followup ( p < 0.001 ) , implying a 6% gain ( gain over the baseline bmi ) between the 1st and 2nd followups ( p < 0.001 ) .
platelet counts were reduced by 22% in the bpd - ds group from 308  10/l at baseline to 240  10/l at the 1st followup ( p < 0.001 ) and were unchanged at the 2nd followup ( 244  10/l ,  p < 0.001 ) , as shown in figure 1(b ) . in the rygbp group , platelet counts were reduced by 10% from 297  10/l at baseline to 266  10/l at the 1st followup ( p = 0.012 ) but were 292  10/l at the 2nd followup ( p = 0.687 ) , implying a 9% increase between the 1st and 2nd followups ( p = 0.024 ) .
katal / l at the 1st followup ( p = 0.01 ) and was 0.32
katal / l at the 2nd followup ( p < 0.001 ) , but this further decrease was not significant ( p = 0.867 ) , as shown in figure 1(c ) . in the rygbp group , ggt
katal / l at the 1st followup ( p < 0.001 ) , with no further alteration at the 2nd followup ( 0.31 katal / l , p < 0.001 ) .
katal / l at the 1st followup ( p = 0.004 ) and was unchanged at the 2nd followup ( 0.41  katal / l , p = 0.004 ) . in the rygbp group ,
katal / l at the 2nd followup ( p < 0.001 ) , implying a further decrease by 16% between the 1st and 2nd followups ( p = 0.02 ) .
the main findings in this study were that liver enzymes , ggt and alt , markedly decreased over time after both rygbp and bpd - ds surgeries , but platelet counts only decreased significantly after bpd - ds .
the alteration in platelet counts showed a somewhat different pattern after rygbp , with a reduction at the 1st followup but no significant change at the 2nd followup .
it might be speculated that the sustained reduction in platelet counts may indicate a long - term improvement in the inflammation of the liver and a more pronounced decrease of liver - fat - content - related inflammation in obese patients treated by bpd - ds compared to rygbp .
platelets vary daily and are depending on a variety of issues such as ethnicity , age , and gender .
buckley et al . have showed in their analysis of serial platelet counts from 3,789 subjects that the repeatability of the platelet count is very high .
obesity is an inflammatory condition [ 23 , 24 ] and a major risk factor for the development of nafld and liver disease . in obese patients ,
ultrasonographic examinations as well as liver biopsies have revealed that nafld is very common . as it is difficult to perform biopsies in all nafld patients ,
it has been reported that a lowered ggt may best predict improvements in inflammation and fibrosis in the hepatocytes in nafld , which are two major prognostic features in this condition , whereas changes in aminotransferase concentrations did not predict change in steatosis .
furthermore , increased numbers of platelets are observed in conditions with low - grade inflammation , such as obesity , although the platelet counts are within normal ranges .
overweight , obese , and morbidly obese females have significantly elevated platelet counts compared with normal - weight females and male subgroups .
the gender difference in platelets might be due to the higher body fat mass in females .
higher platelet counts are associated with more adverse clinical outcomes in patients with myocardial infarction and stroke .
obesity is also associated with platelet dysfunction , increased adhesiveness , and activation [ 2628 ] . in more severe states of nafld with fibrosis , a consumption of thrombocytes are observed . in a recent study ,
yoneda et al . used liver biopsies to evaluate the clinical usefulness of measuring platelet counts for predicting the severity of liver fibrosis in 1,048 patients with nafld .
our data show a sustained reduction in platelet counts over time after bpd - ds , probably induced by a more pronounced weight loss than after rygbp and possibly a more pronounced decrease of liver inflammation .
one year after rygbp , a significant reduction in platelet counts was observed , which is in accordance with 1 year data from dallal et al . , but the reduction was not sustained at the 2nd followup , 3 years after surgery .
there are several limitations in the present study such as the small number of patients and the lack of a morbidly obese control group followedup over 3 years
. however , such patients can be logistically difficult to follow for long term followups .
the bpd - ds group was significantly younger than the rygbp group , but no differences were observed between the two groups at baseline in platelet counts , ggt or alt . body fat content and liver fat content , measured by imaging techniques such as dual energy x - ray absorptiometry or ultrasonography , would have been warranted to investigate if and how different fat distribution might influence the variables analyzed in this study .   in conclusion , morbidly obese patients treated with rygbp and bpd - ds show a marked and sustained decrease in ggt and alt .
a significant reduction in platelets , a marker for inflammation and fibrosis in nafld , was observed in both groups after 1 year but only in bpd - ds over time , which may indicate improvements in general inflammatory status and particularly steatohepatitis .

Answer:
background . obesity is characterized by liver steatosis , chronic inflammation , and increased liver enzymes , that is , gamma - glutamyltransferase ( ggt ) and alanine aminotransferase ( alt ) , markers for nonalcoholic fatty liver disease ( nafld ) and liver fat content . increased platelet counts ( pcs )
 are associated with inflammatory conditions and are a valuable biomarker of the degree of fibrosis in nafld .
 we investigated alterations in pc , ggt , and alt after biliopancreatic diversion with duodenal switch ( bpd - ds ) and roux - en - y gastric bypass ( rygbp ) .
 methods . ten morbidly obese patients ( body mass index , bmi : 53.5  3.8  kg / m2 ) who underwent bpd - ds were evaluated preoperatively ( baseline ) and 1 year ( 1st followup ) and 3 years ( 2nd followup ) after surgery and compared with 21 morbidly obese patients ( bmi : 42.3  5.2  kg / m2 ) who underwent rygbp . results . over the 3 years of followup , changes in bpd - ds and rygbp patients ( bpd - ds / rygbp ) were as follows :
 bmi ( 44%/24% ) , ggt ( 63%/52% ) , and alt ( 48%/62% ) .
 pc decreased ( 21% ) statistically significantly only in bpd - ds patients .
 conclusions .
 morbidly obese patients treated by rygbp or bpd - ds show sustained reductions in bmi , alt , and ggt .
 the decrease in pc and liver enzymes after bpd - ds may reflect a more pronounced decrease of liver - fat - content - related inflammation and , as a result , a lowered secondary thrombocytosis .


Question:
You will be presented with the full text of a biomedical research paper. Please write an abstract for this paper. Your response should include the abstract and no additional text.

Paper text:
acute liver failure ( alf ) is a rare but life - threatening illness which occurs mostly in young adults without any known underlying liver disease [ 1 , 2 ] . in the united states ,
the most common cause of alf is acetaminophen overdose ( 39% ) but in 13% of cases , the causes are indeterminate .
epstein - barr virus ( ebv ) is a dna virus associated with infectious mononucleosis ( i m ) in children and young adults .
it may cause moderate and transitory increase of liver enzymes ; however , in rare cases , severe liver injury and even fatal alf may occur .
we report a case of successful orthotopic liver transplantation ( olt ) in a 67-year - old female who presented with ebv - associated alf .
a 67-year - old woman with bilateral osteoarthritis of the knee , hypothyroidism and recurrent deep vein thrombosis presented with 3 weeks of fatigue and a 1-week history of jaundice .
her medications include diclofenac , rivaroxaban , desiccated thyroid , alprazolam , selenium and glucosamine .
four weeks prior to admission , the patient was found to have mildly elevated serum aminotransferases during a routine visit .
one week prior to admission , she reported to become jaundiced and her aminotransferases were found to be elevated to about 1,000
one day prior to admission , her serum alanine aminotransferase ( alt ) was 3,542 u / l , aspartate aminotransferase ( ast ) was 3,610
u / l and her inr was 2.7 . on admission , her vital signs were normal , and a physical exam was positive only for jaundice .
laboratory findings included a white blood cell count of 13,200/l ( neutrophils 84.9% , lymphocytes 12.4% , monocytes 3.5% and eosinophils 0.2% ) .
u / l , ast was 1,236 u / l , alp was 215 u / l and inr was 2.9 .
hepatic artery , hepatic veins , and portal vein were patent , with a normal direction of flow by doppler study .
serum acetaminophen level was 7 g / ml . hav antibody , hbsag , hcv and hev antibody were all negative .
blood tests for human immunodeficiency virus ( hiv , hiv1/2 antibody and p24 antigen ) , cytomegalovirus ( cmv ) , rubella and rubeola were negative .
antinuclear antibody , anti - mitochondrial antibody and anti - smooth muscle antibody were negative . the patient was initially diagnosed with alf possibly , secondary to diclofenac use , because she had begun to take diclofenac potassium 50 mg twice daily since 5 months ago .
she was admitted to the icu and received multiple transfusions of fresh - frozen plasma ( ffp ) to correct her coagulopathy .
she was given midodrine and octreotide and underwent hemodialysis for hepatorenal syndrome . despite multiple transfusions of ffp , her coagulopathy worsened , and her inr was 3.7 the following day .
her serum alt and ast decreased rapidly in the following 2 days and the patient became more lethargic and somnolent , and difficult to arouse .
four days after admission , she underwent a successful liver transplantation from a cmv - negative , ebv ( igg ) positive cadaveric donor .
the explanted liver was significantly smaller than normal indicating acute failure of the liver ( fig .
after transplantation , she received thymoglobulin , methylprednisolone taper and was later switched to prednisone taper , and she also started tacrolimus 4 days after transplantation .
( a ) small explanted liver weighing 720 g. ( b , c ) histologically , the liver showing 75% of parenchyma extinction and massive necrosis with sinusoidal lymphocytosis and atypical lymphocytes ( h&e , b :  100 ; c :  400 ) .
( d ) ebv in situ hybridization ( left ,  600 ) and cd20 immunostain ( right ,  600 ) showing numerous ebv - positive atypical b lymphocytes .
her histological report of the explanted liver showed that there was 75% massive hepatic parenchyma necrosis ( fig .
there were also acidophilic bodies , microvesicular steatosis and mild macrovesicular steatosis present in the residual hepatic parenchyma .
there was a mixed population of inflammatory cells with predominant lymphocytes with sinusoidal lymphocytosis ( fig .
1d , left ) and positive for cd20 immunostain ( 1:100 dilution , horse radish peroxidase technique ; dako , carpenteria , ca ) ( fig .
hsv staining of the liver tissue was negative although the serum antibodies were slightly higher than normal .
a review of the liver biopsy 5 days prior to admission showed about 25% hepatic parenchyma necrosis with bridging necrosis ( fig .
a whole blood assay for ebv dna using pcr of edta anticoagulated peripheral blood showed 462,000 copies / ml .
she was started on intravenous acyclovir immediately after the diagnosis of ebv infection , and later she was switched to oral acyclovir which was administered for 3 months .
two weeks after transplantation , ebv viral capsid antigen ( vca)-igg test was positive and vca - igm was negative , ebv d early antigen ( ea - d ) and epstein - barr nuclear antigen ( ebna ) were negative .
one month later , the transplanted liver underwent biopsy and showed negative cd20 and ebv rna ( data not shown ) .
the patient is presently doing well 6 months after liver transplantation with no evidence of clinical ebv infection or lymphoproliferative disease .
( a , b ) liver showing 25% parenchyma necrosis with bridging necrosis , acidophilic bodies , mixed inflammatory infiltrate and sinusoidal lymphocytosis ( a :  100 ; b :  400 ) .
( c ) ebv in situ hybridization showing occasional ebv - positive b lymphocytes (  400 , arrows ) .
lt : liver transplant ; acv : acyclovir ; alp : alkaline phosphatase ; ast : aspartate aminotransferase ; alt : alanine aminotransferase .
we describe a case of alf - associated with ebv infection in a previously healthy elderly woman that underwent successful emergent liver transplantation .
fulminant liver failure  , is a sudden and severe hepatic injury in patients without previous liver diseases .
the clinical manifestation usually includes loss of hepatic function , coagulopathy , hepatic encephalopathy and in many cases , progressive multi - organ failure [ 1 , 2 ] . despite recent advances in intensive care management ,
it has been reported that 5-year survival rate is about 80% in patients who underwent emergency liver transplantation for alf .
the etiologies of alf vary greatly by country and have evolved over time . in the unites states ,
drug - induced alf , mainly acetaminophen , accounts for about 58% of cases , and hepatitis a and b accounts for 14% of cases according to the us acute liver failure study group data .
these cases often follow a relatively insidious presentation before patients quickly develop liver failure , and rates of survival are poor without transplantation .
recent studies showed that the cause may be related to ebv infection . in our case
, the cause of alf was initially thought to be diclofenac , because the patient had been taking diclofenac for about 5 months prior to admission , and other causes such as acetaminophen , infectious agents and metabolic diseases were excluded through serological tests ; however , the biopsy and blood ebv dna pcr results confirmed that ebv is the major cause of alf , and diclofenac may have played no or a minor role in this process .
ebv - associated alf is very rare , accounting for only 0.21 % of adult alf cases .
it usually occurs in adults younger than 40 years of age , which is consistent with the fact that young adult patients tend to have symptomatic infectious mononucleosis [ 10 , 11 ] .
it has been reported that patients with neoplasm , cmv and hiv and patients on immunosuppressant drugs are at high risk for ebv - associated alf , although recent studies also showed that immunocompetent patients can also develop alf , indicating that other unknown risk factors may also be involved in the development of ebv - associated alf [ 12 - 14 ] . in adult aged 60 years or older , there were only two cases of ebv - associated alf in the literature ; however , both of them had impaired immune system : one had just started steroids and the other had recent heart surgery [ 15 - 17 ] . in our case , the patient does not have any of the above mentioned problems and did not take any immunosuppressant medications .
this is the first case of ebv reactivation - associated alf in a healthy elderly patient .
this indicates that in older immunocompetent patients presenting with alf , a primary ebv infection or ebv reactivation should be considered when other causes have been excluded
. early diagnosis of ebv - associated hepatitis was difficult as reliable diagnostic criteria are not clearly defined .
molecular approaches , such as ebv - dna pcr or eber - rish , are frequently used to diagnose ebv - related hepatitis [ 9 , 18 ] .
serological ebv tests such as vca - igm , vca - igg , ea - d and ebna can also help to detect a recent infection or a prior infection , or a reactivated ebv infection , although they are not reliable , especially in the elderly , as they have significantly higher titers of the serum tests than young adults [ 9 , 18 ] . in our case ,
the liver biopsy 1 week before admission showed 25% hepatic necrosis , some atypical b lymphocytes with positive ebv rna . in explanted liver
, there was over 75% necrosis , significantly increased atypical b cells and strongly positive expression of ebv rna , which is consistent with the progression of the liver failure .
we also tested the blood ebv level by pcr 4 days after liver transplantation and it was extremely high , indicating a severe active ebv infection .
the ebv serology tests 10 days after liver transplantation showed very high vca - igg but normal vca - igm , indicating that this is an ebv reactivation .
moreover , the liver enzyme showed cholestatic enzyme changes after transplantation with continuously increased alp .
we think that the increased alp was due to damage caused by ebv infection to the implanted liver .
treatment with acyclovir should be strongly considered after liver transplantation for alf from ebv to prevent infection of the liver graft during the period of high level immunosuppression .
first , we were not able to diagnose ebv hepatitis until after evaluation of the explanted liver .
liver transplantation could be potentially avoided if an early diagnosis of ebv hepatitis could have been made .
second , the ebv pcr test was done after transplantation , when patient had already been on steroids .
the extremely high ebv pcr value may not reflect the severity of ebv infection , as steroids can suppress the immune system and ebv could replicate faster than expected .
third , the serological test was done 10 days after we started acyclovir , which may not show the initial changes of ebv infection .
in addition , the use of diclofenac in this patient since a few months ago might have caused some initial injury to the liver .
diclofenac is reported to cause liver injuries by two main mechanisms , hypersensitivity and metabolic aberration [ 19 , 20 ] .
acute liver injury caused by diclofenac is thought to be due to hypersensitivity and usually presents within days to a few weeks after starting diclofenac , which can result in fatal liver failure .
metabolic aberration can cause persistent mild liver injury and once diclofenac is stopped , the liver can recover quickly . in our patient , diclofenac might have caused mild liver injury initially ; however , the reactivation of ebv plays a major role in developing alf .
we are confident that ebv is the cause of alf in the patient based on liver enzyme changes , characteristic histopathological changes , and most importantly strong ebv rna expression in the explanted liver . in conclusion
, our case demonstrates that ebv infection or reactivation may be under - recognized as a cause of alf .
early recognition and diagnosis is extremely important , however difficult . in both healthy young and elderly adults with alf
liver biopsy should be strongly considered in patients with unexplained alf with hepatitis pattern and ebv rna by in situ hybridization should be mandatory if sinusoidal lymphocytosis is present .
emergent liver transplantation is the only definitive treatment option , with very favorable prognosis for such patients .
treatment with acyclovir should be strongly considered after liver transplantation for alf from ebv to prevent infection of the liver graft during the period of high level immunosuppression .

Answer:
acute liver failure ( alf ) is a rare illness with a high mortality rate .
 the only favorable management is emergent liver transplantation .
 about 13% of alf cases have no clear etiology .
 epstein - barr virus ( ebv)-associated alf accounts for less than 1% of all alf cases , and is seen mostly in adults younger than 40 years .
 there are only a few cases of ebv - associated alf in elderly immunocompromised adults .
 we report a case of alf in an immunocompetent 67-year - old woman caused by ebv infection that was treated by orthotopic liver transplantation ( olt ) .
 the diagnosis of ebv - associated alf was established by ebv - dna polymerase chain reaction ( pcr ) and ebv - encoded rna ( eber - rna ) in situ hybridization ( eber - rish ) .
 the patient is currently doing well 6 months after transplantation without any evidence of clinical ebv infection .
 this case illustrates the importance of early recognition and diagnosis of ebv - associated alf by detection of ebv from liver biopsy , especially when patients are immunocompetent and other causes are excluded . to the best of our knowledge ,
 this is the first case of ebv - associated alf present in an immunocompetent elderly female .


Question:
You will be presented with the full text of a biomedical research paper. Please write an abstract for this paper. Your response should include the abstract and no additional text.

Paper text:
urinary tract infections ( utis ) are one of the inflammatory diseases produced by high multiplication of many pathogens in the urinary apparatus , resulting in alterations in the perfect function of the urinary tract and kidneys .
uti is particularly a major problem for females ; nearly 5080% of the female population endures from uti at least once in lifetime and 20 - 50% of them will have recrudescent events ( 1 , 2 ) .
escherichia coli is the most frequent pathogen responsible for up to 80% of utis ( 3 ) .
this bacteria is responsible for 85% and 50% of community and hospital acquired utis , respectively ( 4 ) .
uropathogenic e. coli ( upec ) strains have special virulence factors , including pili or fimbriae , which mediate attachment to uroepithelial and vaginal cells , resistance to human serum bactericidal activity , haemolysin production , and increased amounts of k capsular antigen ( 5 ) .
furthermore , virulence factors of upec strains have a significant role in development of utis .
the most virulence factors dependent upon the upec include adhesions ( type 1 fimbriae , p fimbriae , curli mbriae , ambrial adhesion and flagellum ) , aerobactins , hemolysins , and cytotoxic necrotizing factor 1 .
the mentioned virulence factors are important in colonization of upec , extra - intestinal survival , and creation of cytopathic effects .
in addition , the expression of special virulence factors of upec can contribute to uropathogenicity , as well as worsening of utis ( 1 , 6 , 7 ) . an essential step for beginning and development of uti is bacterial attachment to uroepithelial cells .
e. coli attachment is mediated by ligands of bacteria ( generally small proteins placed at the tips of bacterial fimbriae ) which bind to host cell wall carbohydrate residues , working as receptors ( 5 ) .
therefore , the adherence of e. coli to host receptors is a function , usually mediated by adhesions of bacteria to host cell receptors ( 8) .
the bacterial attachment permits bacteria to resist mechanical elimination by the flow of urine and bladder emptying and increasing persistence of e. coli .
upec strains produce different types of adhesins , including type 1 fimbriae , which are essential for recognition and attachment to urinary tract receptors ( 9 ) . among adhesions of upec ,
the adhesive subunit of type 1 fimbriae , fimh , is a major determinant , which has high tropism for urinary tract receptors ; thus , fimh adhesion is important in colonizing different niches of e. coli ( 10 ) .
in addition , single - nucleotide polymorphism ( snp ) analysis of fimh is a screening tool for epidemiological typing of upec ( 11 , 12 ) . therefore , the research on bacterial virulence factors can result in expansion and development of new methods for diagnosis and prevention of utis .
for more subsequent investigations , the fimh gene was detected in upec strains isolated from hospitalized and out - patients with uti , referred to educational hospitals of shahrekord .
the present study was conducted for detection of the fimh virulence gene from upec isolated from both hospitalized patients and outpatients with uti , referred to educational hospitals of shahrekord , iran .
in this study , 140 isolated e. coli strains from patients with uti were evaluated .
the isolates were collected from both hospitalized and non - hospitalized patients with utis from april to july 2012 from kashani and hajar hospitals , shahrekord , iran . hospitalized infections were characterized as patients who were confined to bed in hospital and non - hospitalized infections were characterized as infections in patients who had no prior contacts with hospitals or long - term care facilities two weeks prior to admission .
the samples were cultured on macconkey agar , blood agar and eosin methylene blue ( emb ) agar ( hi media , india ) .
the plates were incubated at 35c for 24 hours and pure isolates were characterized and identified according to gram staining and biochemical tests such as catalase , oxidase , indole production , citrate utilization , triple iron sugar , ortho - nitrophenyl--galactoside ( onpg ) test , and methyl red - voges proskauer , as described in standard bacteriological methods .
all the above chemicals and media were purchased from sigma - aldrich ( germany ) .
genomic dna templates for pcr amplification were gained from overnight growth of bacterial isolates on luria - bertani agar ( hi media , india ) , pelleted by centrifugation , resuspended in 500 l of sterile deionized water , and boiled for 10 minutes .
after centrifugation of the boiled samples at 19000 g for five minutes , the supernatant was applied as the dna template for pcr .
the bacterial isolates were subjected to screening for the presence of the fimh gene by pcr .
the nucleotide sequence of the primers and the annealing temperature for amplification of the fimh gene by pcr are shown in table 1 .
pcr was carried out in 25 l containing 2.5 l of 10  pcr reaction buffer with mgcl2 ( 1.6 mm ) , 0.5 l ( 200 m ) of deoxynucleoside triphosphates mixture ( dntps , 10 mm ) , 0.5 l of each primer ( 10 pm/l ) , 2 l of the dna template ( 50 ng ) with 0.5 l ( 3 u/l ) taq dna polymerase . the amplification condition included an initial denaturation ( 96c for three minutes ) , 37 cycles ( 96c for 30 seconds , 64c for five minutes , 72c for 60 seconds ) and a final extension ( 72c for fiv eminutes ) .
the pcr amplifications were performed on a thermocycler tc-512 ( bio - techne , cambridge uk ) and the pcr products were analyzed by polyacrylamide gel ( 8% ) electrophoresis . a molecular marker ( fermentas sm0321 , 100 bp ) was used to assess the pcr products sizes .
in this study , 140 isolated e. coli strains from patients with uti were evaluated .
the isolates were collected from both hospitalized and non - hospitalized patients with utis from april to july 2012 from kashani and hajar hospitals , shahrekord , iran . hospitalized infections were characterized as patients who were confined to bed in hospital and non - hospitalized infections were characterized as infections in patients who had no prior contacts with hospitals or long - term care facilities two weeks prior to admission .
the samples were cultured on macconkey agar , blood agar and eosin methylene blue ( emb ) agar ( hi media , india ) .
the plates were incubated at 35c for 24 hours and pure isolates were characterized and identified according to gram staining and biochemical tests such as catalase , oxidase , indole production , citrate utilization , triple iron sugar , ortho - nitrophenyl--galactoside ( onpg ) test , and methyl red - voges proskauer , as described in standard bacteriological methods .
all the above chemicals and media were purchased from sigma - aldrich ( germany ) .
genomic dna templates for pcr amplification were gained from overnight growth of bacterial isolates on luria - bertani agar ( hi media , india ) , pelleted by centrifugation , resuspended in 500 l of sterile deionized water , and boiled for 10 minutes .
after centrifugation of the boiled samples at 19000 g for five minutes , the supernatant was applied as the dna template for pcr .
the bacterial isolates were subjected to screening for the presence of the fimh gene by pcr .
the nucleotide sequence of the primers and the annealing temperature for amplification of the fimh gene by pcr are shown in table 1 .
pcr was carried out in 25 l containing 2.5 l of 10  pcr reaction buffer with mgcl2 ( 1.6 mm ) , 0.5 l ( 200 m ) of deoxynucleoside triphosphates mixture ( dntps , 10 mm ) , 0.5 l of each primer ( 10 pm/l ) , 2 l of the dna template ( 50 ng ) with 0.5 l ( 3 u/l ) taq dna polymerase . the amplification condition included an initial denaturation ( 96c for three minutes ) , 37 cycles ( 96c for 30 seconds , 64c for five minutes , 72c for 60 seconds ) and a final extension ( 72c for fiv eminutes ) .
the pcr amplifications were performed on a thermocycler tc-512 ( bio - techne , cambridge uk ) and the pcr products were analyzed by polyacrylamide gel ( 8% ) electrophoresis .
a molecular marker ( fermentas sm0321 , 100 bp ) was used to assess the pcr products sizes .
the fimh gene was amplified using specific primers and appeared as a band of about 164 bp on polyacrylamide gel ( figure 1 ) .
the fimh gene was found in 130 isolates ( 92.8% ) of upec . of the 130
isolates positive for the fimh gene , 62 ( 47.7% ) and 68 ( 52.3% ) belonged to hospitalized patients and outpatients , respectively .
coli clinical isolates containing the fimh gene ( 164 bp ) ; lane 13,negative control ( without dna template ) ; lanes 14 - 17 : e. coli clinical isolates containing the fimh gene ( 164 bp ) .
the onset of uti results from the ability of upec attachment to urinary tract epithelial cells by specific adhesions including type 1 fimbriae ( 13 ) .
upec strains have many virulence factors which enhance their capacity to colonize in the urogenital tract .
attachment to the urothelial cell surface is mediated by fimh adhesion , placed at the tip of the type 1 fimbriae , which prevents bacterial washout by urine flow and starts bacterial invasion ( 4 , 14 ) . since the fimh virulence factor associated with uti cases
was not widely determined from the upec isolated from both hospitalized patients and outpatients with utis referred to educational hospitals of shahrekord , iran , the prevalence of the fimh gene was examined .
the presence of the fimh gene was confirmed by pcr and the results indicated that the fimh gene was present in 130 upec isolates ( 92.8% ) ; 62 isolates ( 47.7% ) of hospitalized patients and 68 ( 52.3% ) of outpatients .
this showed that most of the upec strains had the fimh gene and our results were almost in accordance with the results of previous literature .
( 15 ) reported that among the studied virulence genes of upec strains , the fimh gene was the most prevalent virulence gene and was found in 68% ( 61/90 ) of the uti isolates .
( 16 ) studied 18 upec isolates collected from females and found that the fimh gene was the most prevalent virulence factor and 100% of the isolates had that gene . in another study ,
17 ) demonstrated that the fimh gene was the most frequent virulence gene and was detected in 98% of e. coli strains isolated from patient with utis .
( 7 ) evaluated the distribution of virulence genes among the studied upec and showed that the prevalence of different virulence genes varied from 10% for the cnf gene to 80% for the fimh gene .
in addition , arabi et al . ( 18 ) investigated the frequency of fimh and other adhesions genes in upec and determined the fimh gene frequency as 87.7% .
apart from investigation on evaluation of the fimh gene in upec strains , this gene has been detected in other strains of e. coli .
for example , kaczmarek et al . ( 13 ) evaluated and detected the genes encoding virulence factors among e. coli strains with k1 antigen as well as the non - k1 e. coli strains .
they found that the fimh gene existed in the whole tested e. coli k1strains as well as in 97.0% of non - k1 strains .
( 19 ) also reported that the fimh gene was present in 54.55% of avian pathogenic e. coli ( apec ) strains which are pathogenic for birds . in another study ,
20 ) showed that in enterohemorrhagic e. coli ( ehec ) strains , the fimh gene was conveyed by the majority of non - o157:h7 e. coli strains ( 97% ) and by all the o157:h7 e. coli strains .
( 21 ) detected the fimh gene in all the e. coli isolates from bovine mastitis .
moreover , fimh snp analysis is a typing tool for epidemiological studying of community- and hospital - associated e. coli isolates and could be used as an easy , cheap screening test for genotypic analyses of upec ( 11 , 12 ) .
we can conclude that type 1 fimbriae is present among upec as well as other strains of e. coli , to the extent that the fimh gene was detected in more than 90% of the e. coli strains . the high binding ability of fimh could result in increased bacterial binding to target cells and increased pathogenicity of e. coli ; thus , fimh could be used to design vaccine for prevention of e. coli infections by blocking the bacterial attachment and colonization .
in addition , fimh could be used as a tool for the extension of rapid detection - based assays .

Answer:
background : urinary tract infections ( utis ) are one of main health problems caused by many microorganisms , including uropathogenic escherichia coli ( upec ) .
 upec strains are the most frequent pathogens responsible for 85% and 50% of community and hospital acquired utis , respectively .
 upec strains have special virulence factors , including type 1 fimbriae , which can result in worsening of utis.objectives:this study was performed to detect type 1 fimbriae ( the fimh gene ) among upec strains by molecular method.materials and methods : a total of 140 isolated e. coli strains from patients with uti were identified using biochemical tests and then evaluated for the fimh gene by polymerase chain reaction ( pcr ) analysis.results:the upec isolates were identified using biochemical tests and were screened by pcr .
 the fimh gene was amplified using specific primers and showed a band about 164 bp .
 the fimh gene was found in 130 isolates ( 92.8% ) of the upec strains .
 of 130 isolates positive for the fimh gene , 62 ( 47.7% ) and 68 ( 52.3% ) belonged to hospitalized patients and outpatients , respectively.conclusions:the results of this study indicated that more than 90% of e. coli isolates harbored the fimh gene . the high binding ability of fimh could result in the increased pathogenicity of e. coli ; thus , fimh could be used as a possible diagnostic marker and/or vaccine candidate .


Question:
You will be presented with the full text of a biomedical research paper. Please write an abstract for this paper. Your response should include the abstract and no additional text.

Paper text:
ganglioneuromas are rare benign tumors of neural crest origin ; they arise from peripheral sympathetic ganglia or the adrenal glands .
these tumors are most commonly discovered in older pediatric patients or adults ; they are discovered incidentally , through thoracic or abdominal imaging studies performed for unrelated conditions .
intracranial involvement of ganglioneuromas is extremely rare ( 1 , 2 ) , and there has been only one report of ganglioneuroma arising from the trigeminal nerve .
we report a very rare case of trigeminal ganglioneuroma in the prepontine and cerebellopontine angle cistern , in a 44-year - old female and describe the magnetic resonance ( mr ) imaging characteristics , including diffusion - weighted imaging ( dwi ) findings .
a 44-year - old female was admitted to our hospital because of a 2-year history of facial pain and numbness in the left side .
the patient complained of an intermittent stabbing pain and numbness over the left zygomatic region .
a brain mr imaging study was performed with a 3 t unit ( magnetom triotim , siemens , erlangen , germany ) , which revealed a 2  1.8  1.5 cm well - circumscribed mass in the prepontine and cerebellopontine angle cistern on the left side ( fig .
the left fifth cranial nerve was displaced superomedially , and the seventh - eighth nerve complex inferiorly by the mass .
the mass showed homogeneous iso - signal intensity on a t1-weighted image relative to the brain parenchyma ( fig .
1a ) as well as heterogeneous increased signal intensity on a t2-weighted image ( fig .
the apparent diffusion coefficient ( adc ) values were obtained using a circular region of interest with a diameter of 6 mm at 4 nonoverlapping locations in the tumor ( fig .
the mean adc values obtained with b values of 0 and 1000 sec / mm of the tumor were 0.72  10 mm / s , compared to 3.01  10 mm / s for csf ( measured in the fourth ventricle ) and 0.71  10 mm / s for adjacent brain tissue ( measured in the pons ) .
the preoperative diagnosis for this poorly enhancing mass with a dwi high signal intensity lesion in the prepontine and cerebellopontine angle cistern was an epidermoid cyst .
, a well - circumscribed solid mass was found to be firmly attached to the trigeminal nerve .
histopathologic examination demonstrated a benign tumor composed of mature ganglion cells and spindle - shaped cells in an abundant collagenous stroma ( fig .
postoperatively , facial pain and numbness disappeared , and follow - up mr imaging , obtained 16 months later showed no evidence of tumor recurrence .
ganglioneuromas are typically found within the posterior mediastinum and retroperitoneum , though less common locations include the adrenal medulla , parapharyngeal region , and visceral ganglia .
rarely , ganglioneuromas have been observed in the tongue , prostate , skin , and bone ( 3 ) .
intracranial ganglioneuroma is extremely rare , and only a few cases have been reported in previous literature ( 1 , 2 ) .
histologically , these tumors are composed of single or clustered mature ganglion cells and mature schwann cells ( 3 ) .
typical radiologic findings of ganglioneuroma arising from the peripheral sympathetic nerve have been described . at ct , ganglioneuromas are well - demarcated hypoattenuated lesions , with calcifications in 20 - 42% of cases .
these tumors are not significantly enhanced after the administration of contrast materials , but delayed ct images can show slight or moderate enhancement ( 3 , 4 ) . at mr , ganglioneuromas are generally hypointense on t1-weighted images and heterogeneously hyperintense on t2-weighted images with respect to adjacent muscle .
( 1 ) reported the first case of trigeminal ganglioneuroma and described conventional mr imaging findings , which are similar to those of thoracoabdominal ganglioneuromas . mr images included in their report demonstrated a well - defined mass with low signal intensity on a t1-weighted image , high signal intensity on a t2-weighted image , and relatively homogenous enhancement on a post - contrast t1-weighted image . in our patient ,
the lesion was iso - signal intense to the adjacent pons on the t1-weighted image and showed slightly increased signal intensity on the t2-weighted image .
it has previously been reported that ganglioneuromas with markedly high signal intensity on a t2-weighted image histologically consist of a large amount of myxoid stroma and relatively few cellular components and collagen fibers .
in contrast , tumors with intermediate to subtle high signal intensities on a t2-weighted image , as in our case , consisted of numerous cellular and fibrous components and few myxoid stroma ( 4 , 5 ) . in our case , the mass showed poor enhancement on a postcontrast t1-weighted image .
thoracoabdominal ganglioneuromas can demonstrate gradually increasing enhancement with dynamic mr imaging ( 3 - 5 ) .
diffusion - weighed imaging findings and adc values with regard to intracranial ganglioneuroma have not been published previously .
our case showed a homogeneous hyperintense signal throughout the tumor , on a dwi , and revealed a mean tumor adc value of 0.72  10 mm / s .
( 6 ) recently reported dwi findings of the ganglioneuromas / ganglioneuroblastomas originating from the thoracoabdominal sympathetic nervous system .
these tumors showed relatively high adc values ( mean adc : 1.60  10 mm / s , range 1.13 - 1.99  10 mm / s ) .
the differences between gahr 's cases and our case may be due to the different tumor histopathologies .
one might postulate that high cellular density and scanty myxoid stroma , revealed through histopathology , may be attributed to relatively low adc values in our case .
( 7 ) reported that focal central hemorrhages were observed in 2 of 17 adrenal ganglioneuromas .
our case showed no intratumoral susceptibility signals on gradient echo images , as well as absence of intratumoral hemorrhage or calcification with histopathology .
an epidermoid cyst should be included in the differential diagnosis of t2-increased signal intensity lesions in the prepontine and cerebellopontine angle cisterns .
the high signal intensity of epidermoid cysts with dwi is caused by the intrinsic t2 shine - through effects of the lesion .
reported adc values of intracranial epidermoid cysts range from 0.98  10 mm / s up to 1.36  10 mm / s ( 8) ; these are higher than the values of trigeminal ganglioneuroma in our case .
other differential diagnoses of masses in the prepontine and cerebellopontine angle cisterns include schwannoma , meningioma , neurofibroma , and metastasis .
the majority of these tumors do not show high signal intensity with dwi and demonstrate relatively strong enhancement on post - contrast t1-weighted images .
other rare tumors that have been reported to occur in the trigeminal nerve include benign triton tumor ( neuromuscular hamartoma ) and ganglioglioma .
neuromuscular hamartomas were reported to be profoundly hypointense on t2-weighted images and demonstrated mild homogenous contrast enhancement ( 9 ) .
a trigeminal ganglioglioma may be difficult to distinguish from a ganglioneuroma like that in our case .
this tumor showed a nonspecific homogenous mr signal intensity indistinguishable from the adjacent brain stem with all imaging sequences and no contrast enhancement ( 10 ) .
dwi findings of neuromuscular hamartoma and ganglioglioma , arising from the trigeminal nerve have not been reported .
trigeminal ganglioneuroma is a very rare tumor ; however , this tumor should be considered in the differential diagnosis of tumors with low adc values in the prepontine and cerebellopontine angle cistern .
trigeminal ganglioneuroma is a very rare tumor ; however , this tumor should be considered in the differential diagnosis of tumors with low adc values in the prepontine and cerebellopontine angle cistern .

Answer:
a case of intracranial ganglioneuroma arising from the trigeminal nerve in the pontine and cerebellopontine angle cistern , in a 44-year - old female , is presented with an emphasis on diffusion - weighted imaging findings .
 we will discuss on how the tumor in the very unusual location should be differentiated particularly focused on diffusion - weighted imaging findings .


Question:
You will be presented with the full text of a biomedical research paper. Please write an abstract for this paper. Your response should include the abstract and no additional text.

Paper text:
cavernous sinus thrombosis ( cst ) was first reported by bright et al . in 18311 .
cst is an infectious disease that is potentially fatal if it is not treated in its early stage .
furthermore , despite treatment , complications of cst such as cranial nerve dysfunction may remain .
there are very few reports of cst related to periodontal disease or to tooth extraction3 .
the authors present a case in which misdiagnosis and inappropriate treatment of a buccal cheek laceration due to an ill - fitting denture resulted in a buccal space abscess that progressed into cst .
a 65-year - old man with no past medical history presented to the emergency room with facial swelling and fever .
two weeks earlier , he began having trismus and pain on the mandibular left side .
the patient was prescribed prednisolone , cyclobenzaprine , steroids and muscle relaxants and was advised to frequently apply moist hot packs .
the patient 's symptoms persisted and he developed spiking fevers with delirium . in the emergency room ,
his vital signs included blood pressure 151/82 mmhg , pulse 95 beats per minute , temperature 39.3 , and respiratory rate 12/min .
a complete blood count revealed a white blood cell ( wbc ) count of 19,110/l with 92.8% neutrophils , a erythrocyte sedimentation rate ( esr ) of 89 mm / h and c - reactive protein ( crp ) of 279.2 mg / l .
computed tomography ( ct ) showed an abscess in the buccal and pterygomandibular space spreading into the temporal space.(fig .
1 ) the patient 's mental status was assessed with questions about his personal information .
he had three teeth on the right mandibular side , and the left buccal cheek was swollen with a 1 cm laceration .
however , because the patient showed clinical signs of infection associated with buccal , pterygomandibular , and temporal space abscesses , he was admitted to the hospital .
empirical antibiotic treatment was initiated with flomoxef 2 g / day , metronidazole 1.5 g / day , and isepamicin sulfate 400 mg / day . on the day of hospitalization
ofloxacin otic solution was topically applied to the external auditory canal and the occlusive dressing was changed daily . on the second day of hospitalization ,
a spinal tap revealed cerebrospinal fluid turbidity suggestive of central nervous system ( cns ) infection .
as per recommendations from internal medicine , and neurology , the antibiotic regimen was changed to ceftazidime 4 g / day and vancomycin 2.7 g / day to cover the cns infection and potential methicillin - resistance staphylococcus aureus ( mrsa ) . on the third day of hospitalization , an oral and maxillofacial surgeon performed intraoral incision and drainage of the buccal and pterygomandibular spaces .
results of a magnetic resonance image ( mri ) included a dilated superior ophthalmic vein , bulging cavernous sinus contour , and septic thrombi in the cavernous sinus .
2 ) antimicrobial sensitivity testing identified methicillin - sensitive staphylococcus aureus ( mssa ) and therefore the antibiotic regimen was changed to nafcillin 12 g / day .
his buccal swelling decreased , he recovered the ability to open his mouth , and his visual acuity and extremity sensation improved .
wbc , esr , and crp counts also improved.(table 1 ) with reduced swelling , we discovered an ill - fitting denture .
cst is a rare condition in which blood clots form within the cavernous sinus , a large collection of thin - walled veins .
septic cst may be caused by sinusitis , otitis , odontogenic infection , or facial cellulitis .
the most frequent cause of septic cst is sinusitis in the sphenoid or ethmoidal sinuses .
dental infections account for < 10% of septic cst cases , and most of these cases are related to maxillary infection4 .
eagleton5 proposed the following criteria for cst diagnosis : a known site of infection ; blood stream infection ( sepsis ) ; early obstructive signs ( such as retinal vein fullness , proptosis , exophthalmus , and collateral venous circulation ) ; ocular nerve paralysis ( via lesions of cranial nerves iii , iv , v , and iv ) ; surrounding soft tissue abscesses ( of the orbit , occiput , neck or nasopharynx ) ; and symptoms of a complicated disease ( such as headache , papilledema , and meningeal signs ) .
other potential pathogens include pneumococcus , bacteroides , fusobacterium , proteus , haemophilus , pseudomonas , and corynebacterium6 .
venous flow is bidirectional in the cerebral vein , emissary vein , and dural sinus because these vessels do not have valves .
therefore , bacteria or thrombi from another facial region can spread to the cavernous sinus via the facial vein or pterygoid plexus7 .
ophthalmoplegia is extraocular muscle weakness that results ( in cst ) when cranial nerves iii , iv , and/or vi are damaged due to their passage through the cavernous sinus .
other symptoms of lethargy , headache , periorbital swelling , papilledema , and venous engorgement occur in 50%-80% of patients . decreased visual acuity , sluggish / dilated pupil , periorbital sensory loss , and decreased corneal reflex are less frequent symptoms that occur in < 50% of patients .
. early symptoms of orbital cellulitis are similar to those of cst and include periorbital swelling , proptosis , chemosis , fever and impaired vision .
cst is included in the differential diagnosis when the above symptoms present bilaterally or when there is sensory loss in the periocular area , papilledema , and pupillary dilation9 .
coronal ct reveals that the lateral wall of the cavernous sinus is flat or convex instead of its normal concave shape . additionally , irregular filling defects due to thrombi , and superior ophthalmic vein dilation are often observed .
mri is useful when the ct images are not clear or when the infection has spread to surrounding tissues including the brain and pituitary gland10,11 . in the past
these imaging techniques are no longer recommended because they increase the risks of the infection spreading and thrombosis12 .
optimal therapy for cst includes the concomitant administration of nafcillin , metronidazole , and ceftriaxone / cefotaxime .
surgical interventions are indicated when the primary site of infection is sinusitis , or a dental infection . in the case of a serious infection ,
one may consider direct surgical drainage of the cavernous sinus ; however , this approach is difficult and complications are likely to arise7 .
corticosteroid therapy must be considered if adrenal insufficiency occurs due to cranial nerve dysfunction or pituitary necrosis13 .
some studies have reported that anticoagulating with heparin , for example , within seven days after cst reduces the mortality rate14 .
however , anticoagulation increases the risk of intracranial and/or systemic hemorrhage , and therefore should be used with caution15 . in this case , it was difficult to confirm the source of infection because the patient 's buccal cheek swelling and trismus prevented adequate intraoral examination .
the only suspicious finding was a small laceration on left buccal mucosa . generally , odontogenic infections arise from the teeth themselves or from periodontal tissue . therefore , it was difficult to confirm that this severe infection originated from a small laceration in a patient with no medical history .
another dentist who examined the patient two weeks before his presentation had misdiagnosed him with temporomandibular joint symptoms and myofascial pain .
administration of moist hot packs and prednisolone may have actually facilitated the infection 's progression .
cst treatment must include proper management of the primary infection site and empiric antibiotics considering the possible pathogens .
cst presents with inconsistent symptoms , and therefore it is essential to collaborate with various departments including neurology , ophthalmology , otorhinolaryngology , and internal medicine .
it presents with proptosis , chemosis , periorbital swelling and other typical signs of infection including as fever , pain and swelling .
clinicians in oral and maxillofacial surgery should be aware of cst and should consider it in patients with facial swelling .

Answer:
cavernous sinus thrombosis not only presents with constitutional symptoms including fever , pain and swelling but also with specific findings such as proptosis , chemosis , periorbital swelling , and cranial nerve palsies .
 it is known to occur secondary to the spread of paranasal sinus infections in the nose , ethmoidal and sphenoidal sinuses . however , paranasal sinus infection of dental origin is rare .
 the following is a case of cavernous sinus thrombosis due to the spread of an abscess in the buccal and pterygomandibular spaces via buccal mucosal laceration .


Question:
You will be presented with the full text of a biomedical research paper. Please write an abstract for this paper. Your response should include the abstract and no additional text.

Paper text:
in this issue of the jem , two articles describe a potential role for two bacterial toxins in the modulation of the immune system by interfering with t cell signaling . using an in vitro jurkat t cell system , gerke et al .
( 8) report that yersinia pseudotuberculosis inhibits t cell activation and that the inhibitory activity was strictly dependent on the yersinia outer protein h ( yoph ) , a potent tyrosine phosphatase that is delivered to host cells by a bacterially encoded type iii protein secretion system .
previous studies by a number of laboratories have identified several tyrosine phosphorylated proteins as apparent targets for the tyrosine phosphatase activity of yoph in cell culture systems .
these include p130cas , focal adhesion kinase , and paxillin in hela cells , and fyb / slap130 , p130cas , and skap55 in macrophages ( 912 ) . in general ,
these are proteins involved in integrin signaling , which is consistent with the proposed role of yoph as an antiphagocytic molecule .
more recent studies have shown that yoph can also inhibit t cell signaling in - vitro and that this activity could be correlated with the presence of yoph and the dephosphorylation of the tyrosine kinase lck ( 13 ) .
( 8) have now extended those studies and added the t cell  signaling adaptor proteins lat and slp-76 to the list of potential yoph substrates .
these adaptor proteins are essential for the transduction of signals from the t cell receptor and its associated tyrosine kinases , and their tyrosine phosphorylation is required for their activities .
( 8) argue that tyrosine dephosphorylation of these adaptor proteins by yoph is responsible for the observed inhibition of t cell receptor signaling after yersinia infection of cultured jurkat t cells .
they also present data that argue that both of these proteins are high affinity substrates of yoph , presumably requiring small amounts of translocated toxin to be targeted for dephosphorylation . in the second article , rossi paccani et al .
( 14 ) report that anthrax toxin also disrupts t cell signaling but by a completely different mechanism . anthrax toxin , which is produced by bacillus anthracis , is composed of two enzymatic or a subunits known as edema factor ( ef ) and lethal factor ( lf ) that alternatively associate with a b subunit , known as protective antigen , which mediates their delivery into target cells ( 15 ) .
ef is a potent calcium / calmodulin - dependent adenylate cyclase , which causes a massive increase of cyclic amp in intoxicated cells and global disruption of cell signaling .
lf is a zinc - dependent protease that specifically disrupts the mitogen - activated protein ( map ) kinase signaling pathways by cleaving the activating map kinase kinases mek1/2 and mkk3 , mkk4 , mkk6 , and mkk7 ( 1619 ) .
( 14 ) showed that treatment of peripheral blood lymphocytes with protective antigen in combination with either lf or ef effectively blocked t cell signaling as measured by the expression levels of the surface activation markers cd69 and cd25 , the production of cytokines , and cell proliferation .
given the ubiquitous presence of the anthrax toxin receptors and the essential role for map kinases and camp in t cell signaling , the results presented by rossi paccani et al .
the broader issue raised by these two and other studies with other bacterial toxins that disrupt immune cell function in vitro , however , is the in vivo relevance of the findings .
do these pathogens specifically interfere with t cell signaling during the course of an infection ? unfortunately , in vitro studies , although useful to provide testable hypotheses , can not provide answers to these important questions
( 8) make a strong case for slp-76 and lat as high affinity substrates for this tyrosine phosphatase and hence of potential relevance during infection when presumably the pathogen would deliver small quantities of this toxin .
indeed , it is often the case that under vitro experimental conditions , cells are exposed to toxin quantities not usually delivered during actual infections .
nevertheless , it is not known how much yoph is delivered by yersinia during infection , and there is no evidence demonstrating that yersinia hampers t cell function during infection .
yersinia infections are usually acute ( 20 ) , arguing against the need for these pathogens to counteract the host - specific adaptive immune responses during infection . however , although rare , chronic infections are sometimes observed ( 21 , 22 ) , and in those cases , the ability to interfere with t cell function might be useful to the pathogen .
whether this function of yoph has been specifically selected by evolution or is simply a  by - product  of another of its demonstrated functions , such as disruption of macrophages during acute infection , remains to be established .
anthrax toxin possesses even a more difficult challenge because its biochemical activity ( such as inhibition of map kinase signaling ) can potentially affect a large number of cellular processes .
therefore , the ability of anthrax toxin to inhibit map kinase signaling can result in the in vitro inhibition of any of the rather large number of intracellular signaling pathways that involve these kinases , regardless of their relevance during infection .
for example , if added to cultured neurons , anthrax toxin would certainly prevent neurite outgrowth , a process strictly dependent on map kinase signaling ( 23 )
. however , it would be hard to argue that this is a relevant function for the toxin during infection . by the same token , anthrax toxin
predictably inhibited in vitro t cell signaling , a process strictly dependent on map kinase signaling .
however , more experiments will be required to establish whether this activity of the toxin is important during infection .
if untreated , b. anthracis infections are usually hyper acute ( 24 ) ; therefore , inhibiting t cell signaling may not provide a significant advantage to the pathogen . on occasions
, b. anthracis can be associated with sub - acute infections ( such as cutaneous anthrax ; reference 24 ) , in which case inhibition of t cell function may provide some advantages to the pathogen . in any case , because b. anthracis is most likely an  accidental
pathogen of mammals , it is unlikely that evolution may have played any role in directly shaping the effects of anthrax toxin on t cells . therefore , this activity might be more a byproduct , relevant or not , of other activities of this toxin in the normal ecology of b. anthracis . although every pathogen must contend with the onslaught of the innate immune responses , it is not necessarily the case that every pathogen must counteract the acquired immune response to fulfill its replication program . for most pathogens that cause acute infections , their life cycle within the host is most often over by the time the naive host mounts a meaningful acquired immune response capable of controlling the infection .
in fact , most infections with pathogens that have coevolved with their hosts are indeed asymptomatic , do not lead to overt harm , and most often result in protective convalescent immunity . on the other hand ,
pathogens that cause persistent infections might be under strong evolutionary pressure to evolve specific mechanisms to avoid acquired immune responses .
indeed , mechanisms of antigenic variation or specific inhibition of antigen presentation evolved by microbial pathogens are well documented ( 25 ) .
for example , many viral pathogens specifically interfere , by a variety of mechanisms , with both major histocompatibility class i and ii antigen - presenting pathways ( 26 , 27 ) .
in addition , many viral , bacterial , and protozoan pathogens undergo rapid antigenic variation to evade the onslaught of the acquired immune response ( 2830 ) . whether inhibition of t cell signaling by anthrax or yoph toxins should be added to the list of pathogenic mechanisms specifically evolved to counter the acquired immune response

Answer:
microorganisms that cause persistent infection often exhibit specific adaptations that allow them to avoid the adaptive immune response . recently
 , several bacterial toxins have been shown in vitro to disrupt immune cell functions .
 however , it remains to be established whether these activities are relevant during infection and whether these toxins have specifically evolved to disrupt the adaptive immune system .


Question:
You will be presented with the full text of a biomedical research paper. Please write an abstract for this paper. Your response should include the abstract and no additional text.

Paper text:
the most important goal of rehabilitation for a lower limb amputee is the independent
 performance of daily activities through restoration of functional walking ability .
miller et al .
 reported that 52% of prosthesis users experienced falls and 49% of amputees have a fear of
 falling .
it also said that the fear of falling limits the daily movement of amputees and
 causes further deterioration of the balance ability required for walking1 .
therefore , physical therapy for lower limb
 amputees should be focused on the prevention of falls during movement / walking for the
 improvement of everyday activities . for this purpose , it is necessary to properly evaluate
 the balance ability of amputees and to perform training to improve the balance ability based
 on the results of that evaluation .
the objectives of the present study were to elucidate
 what type of compensatory movement and postural strategy are used by lower limb amputees for
 posture control during the period from prosthesis fitting to hospital discharge by analyzing
 the muscle activity patterns of the lower limb muscles and to elucidate the changes over
 time in the muscle activity pattern during the course of physical therapy .
elderly patients
 also have a higher risk of falling than younger patients because of biomechanical ,
 physiological , and psychological differences .
however , no study has yet focused on comparing
 time - dependant changes in muscle activity patterns between younger and elderly patients .

therefore , the other purpose of this study was to reveal the differences in muscle activity
 patterns during standing between younger and elderly patients .
a young male , 34  years old , and an elderly female , 84  years old , who had a lower limb
 amputated were the subjects .
neither of the patients had a history of orthopedic or
 neurological disease in the unaffected lower limb or the trunk . a patient who undergoes
 below - knee amputation due to diabetes
has a normal deep sensation in the unaffected ankle
 joint . in both of our cases ,
the fitting between the socket and the stump on wearing was
 well adjusted with no pain in the stump .
the prosthesis used by the lower limb amputees was a total
 surface bearing liner type and a sach foot ( table
 1table 1 .
characteristics of the subjectssubjectssexage ( year)height ( cm)weight ( kg)amputation sitesocketankle jointcauseweek to start pt after amputationweek to wear prosthesis after amputationweek to discharge after wearing prosthesis for
 the first timeyoungm3317572right bkatsbsachtumor174elderf8515045left bkatsbsachdiabetes1514 m : male , f : female , bka : below knee amputee , tsb : total surface bearing , sach : solid
 ankle cushion heel ; j - foot m1170 , pt : physical therapy ) .
surface electromyography ( emg ) measurements were performed of the
 gastrocnemius medial head ( ga ) of the unaffected lower limb .
the electrodes were placed on
 the most prominent bulge of the ga muscle following seniam guidelines .
after sufficient
 treatment with skinpure to reduce the inter - electrode resistance to no more than 10  k on
 the skin , disposable electrodes ( blue sensor , nf-50-k / w , ambu ) were attached at an
 inter - electrode distance of 2  cm .
the emg signals were amplified ( to 1.0  mv ) and band - pass
 filtered between 201,000  hz using a synact mt-11 ( nec corp . , tokyo , japan ) .
the emg signals
 were digitized using a waveform analysis system , power lab 16s ( ad instruments ltd , hasting ,
 uk ) , at a sampling frequency of 1,000  hz , and stored on a personal computer for off - line
 analysis .
after data input , waveform processing was performed using waveform analysis
 software , chart36.8 , ad instruments .
two different tasks of maintaining the static standing
 position were performed on the floor .
the test subjects were asked to stand on the floor
 with their feet shoulder - width apart and look at a point set at 1  m distance to the front at
 the height of the eye for 10 seconds .
the first task , reference task , was to maintain
 upright standing position on the prosthesis while holding parallel bars .
the second task ,
 experimental task , was forward weight shift while maintaining the standing position without
 grasping the parallel bars .
the recorded data were smoothed using the root mean square ( rms )
 value of every 100  msec using waveform analysis software .
the reference contraction is
 judged to be reliable by being reproducible , giving approximately equal results within
 subjects over trial .
therefore , we used the emg of another task as a reference contraction
 for emg normalization . the normalized level of % rmsemg was determined using the following
 formula .
m : male , f : female , bka : below knee amputee , tsb : total surface bearing , sach : solid
 ankle cushion heel ; j - foot m1170 , pt : physical therapy % rmsemg = experimental task rmsemg ( second task ) / reference task rmsemg ( first task )
 100% maximum walking speed was measured in 10  m walking .
depending on the condition at the time of the measurements , subjects
 were allowed to use a crutch , or a single cane on the unaffected side while walking .
the
 surface muscle activity and the walking speed were measured once a week , a total of four
 occasions , starting on the day of prosthesis fitting ( first week ) .
this study was conducted
 after approval was obtained from the ethics committee of tohoku university graduate school
 of medicine .
the study patients were sufficiently informed about the purpose and methods of
 the study , and their consent to participation was obtained .
when the time - dependent changes in muscular activity of ga , which is the most active muscle
 in the standing position , were investigated in the forward weight shift task , two unique
 patterns were observed . for the younger subject ,
no muscle activity of ga was observed in
 the standing position tasks in the first week , but the amount of muscular activity of ga
 gradually increased over time . on the other hand , for the elderly subject , increased
 activity of ga was observed in the forward weight shift task in the first week , when the
 prosthesis was worn for the first time , followed by a gradual decrease in activity over time
 ( table 2table 2 .
time shift of activity in ga ( % rmsemg ) and walking speed ( m / min)week%rmsemg ( % ) mws ( m / min)youngerelderlyyoungerelderlyfirst0.6618.4348.5815.12second4.7116.4873.8924.57third5.9812.6580.3224.33fourth8.855.4110043.17%rmsemg : % root mean square electromyography , mws : maximum walking speed ) .
the maximum walking speed gradually increased over the period from when the
 prosthesis was worn for the first time to when the subjects were discharged from the
 hospital ( table 2 ) .
the basic elements for the smoothest and most energy efficient walk are proper balance
 ability and posture control function2 . in
 lower limb amputation , the contralateral lower limb function influences subsequent ability
 to perform daily living and transfer activities , and standing balance on the unaffected side
 is an important determinant of whether walking with a prosthesis is possible or not3 .
reported that the muscle of
 the unaffected lower limb of prosthesis wearers tended to adopt a balancing strategy to
 compensate for the loss of the ankle joint and muscles due to amputation4 .
therefore , lower limb amputees need to
 adapt to asymmetrical body weight and muscular strength when they exert effort to maintain
 static standing while wearing a prosthesis . in the present study , we evaluated the changes
 in surface emg activity of the gastrocnemius during standing , and the walking speed with a
 prosthesis .
the muscular activity of ga is most conspicuous when the amputee is standing
 with the prosthesis for the first time .
when the static standing position is maintained , the
 ga is activated in preparation for the forward movement of the center of pressure5 , 6 .
we
 found two unique muscle activity patterns were exhibited by the two below - knee amputees .

when the prosthesis was first worn , the younger subject was so careful about maintaining the
 standing posture that adequate forward movement of the center of gravity could not be
 achieved . for the elderly subject
, however , marked activity of the ga was found , and ga
 activity at the final assessment was lower than that of the initial measurement , especially
 during the forward weight shift task .
these time - dependent changes in the muscular activity
 of ga indicate how younger and elderly amputees adapt muscular force to maintain standing
 posture , and it might also be as a cause of falls by elderly patients in the early stage of
 standing or gait training .
the subjects learned the method for shifting the center of gravity forward in a
 stable manner , resulting in the gradual reduction or increase of ga muscle activity .
there are many
 factors known to contribute to the improvement of the walking speed of amputees .
as far as
 the results of this study are concerned , it can be concluded that one important factor is
 regaining the ability to be able to shift the center of gravity in the static standing
 position through the efficient muscle activity of the unaffected lower limb . in conclusion ,
 the trend of muscle activities over time should contribute to the development of effective
 rehabilitation programs .
due to the limited number of subjects included in this study , a statistical analysis of
 sufficient power could not be performed .
furthermore , there were obvious differences in
 biomechanical , physiological , and psychological attributes because of age differences .

biomechanical or physiological perspective approaches are very important . in this study ,
 however , there was no history of disorders of the trunk , such as lordosis or kyphosis , so we
 only focused on the differences in emg .
further studies with larger numbers of subjects
 stratified by the causes and types of amputation are needed to clarify the specific factors
 associated with the acquisition of the ability to walk by amputees , and the development of
 efficient methods for physical therapy and programs .

Answer:
[ purpose ] dysfunction of lower extremity muscles is one risk factor of falls for amputee
 patients .
 however , the change in muscle activity pattern and balance ability of amputees
 who have no experience in standing with prosthesis during the period from prosthesis
 fitting to regaining the ability to walk has never been studied .
 therefore , the objectives
 of the present study were to elucidate changes over time in the muscle activity pattern
 and walking speed from first prosthesis fitting to hospital discharge .
 we also
 investigated the differences of muscle activity during standing between younger and
 elderly amputee patients .
 [ methods ] electromyography measurements were performed on the
 gastrocnemius of the intact leg during standing .
 the test subjects were asked to shift
 their center of gravity forward .
 [ results ] two unique patterns of gastrocnemius activities
 were observed over time . in a younger patient ,
 the amount of muscular activity of the
 gastrocnemius gradually increased over time . in an elderly patient , however , the amount of
 muscular activity of gastrocnemius gradually decreased over time .
 [ conclusion ] the
 time - dependent changes in gastrocnemius muscle activities are indicative postural control
 ability .
 therefore , understanding the time - dependent changes in muscle activities during
 rehabilitation and the differences of postural control between younger and elderly
 patients would contribute to the development of effective rehabilitation programs for each
 patient .


Question:
You will be presented with the full text of a biomedical research paper. Please write an abstract for this paper. Your response should include the abstract and no additional text.

Paper text:
acute embolic limb ischemia is an urgent clinical condition in which sudden decrease or worsening in limb perfusion causes a potential threat to extremity viability and to life .
thorough removal of all occlusive emboli in the arterial tree results in the best outcomes ; hence , some authors favored arteriography after embolectomy for lower limbs .

angiography is traditionally performed with iodinated contrast material , but carbon dioxide ( co2 ) has been studied as an alternative intravascular contrast agent for patients with iodine allergy or renal function impairment .
since it is not nephrotoxic , it was considered reasonable to utilize this contrast in a patient with borderline renal function who would be submitted to the noxious stimuli of the reperfused limb after revascularization .
  to the best of our knowledge ,
this was the first case assessing the intraoperative use of co2 as a substitute for iodine contrast in a patient with known chronic kidney disease and an acute ischemic limb .
a 79-year - old woman presented to the emergency department with acute limb ischemia in her left leg with a 2-hour history .
past medical history was positive for hypertension , atrial fibrillation and non - dialysis - dependent chronic renal failure .
two years before , she had been operated on for acute aortic embolic occlusion , with bilateral femoral catheter embolectomy .
upon discharge she presented pedal pulses , but no posterior tibial pulses on either limb .
medication use was irregular , and her international normalized ratio ( inr ) of prothrombin time upon admission was 1.1 .
her pulse was arrhythmic ; she was hypertensive ( 160x110mmhg ) and presented with normal femoral , popliteal and pedal pulses on her right leg .
on palpation in the left lower limb only a weak femoral pulse was observed ; there were no distal pulses .
she was classified as grade iib limb ischemia ( immediately threatened ) and was immediately referred for surgery .
preoperative exams revealed a diminished creatinine clearance ( cockroft - gault of 12ml / min ) .
arteriotomy was performed and a 4-fr embolectomy catheter was utilized ( edwards lifesciences corp , irvine , california , usa ) .
the catheter progressed more than 60 cm on the superficial artery , but could not be felt neither on pedal artery topography nor on posterior tibial artery topography .
back bleeding was not significant , and a decision was made to perform an angiography to better assess the infra - popliteal arterial tree .
a homemade water seal co2 delivery system was used , similar to another previously described , but with one modification to prevent room - air contamination .
bloomington , indianopolis , usa ) inserted in the arteriotomy while the arteries were clamped .

figure 1 shows a patent popliteal artery , a patent fibular artery and an occlusion on the mid - third of the anterior tibial artery .
we hypothesized that the embolectomy catheter reached the fibular artery on the first attempt , and thus could not be felt on physical exam .

patent popliteal and fibular arteries , occlusion in the mid - third of the anterior tibial artery
  a new embolectomy was then performed .
the catheter progressed to the foot , on the topography of the pedal artery ( i.e. , the catheter could be felt on the projection of the artery ) , and more thrombi were retrieved .
control angiography ( figure 2 ) showed complete resolution of the anterior tibial artery occlusion , with contrast up to the foot ( figure 3 ) .
a total of 28ml of co2 was used , and no iodine contrast was needed .

the arteries were unclamped , and the popliteal and pedal pulses were noted to be present on the limb .
ischemia signs ( e.g. , pallor , hypothermia ) were promptly resolved after arterial flow release .
the patient remained in the intensive care unit ( icu ) until the 11 postoperative day . during this period ,
the patient did not receive any nephrotoxic agent , such as vancomycin or vasoactive drugs .
after icu discharge she developed a urinary tract infection , as well as deteriorating renal function and uremia .
the patient developed pneumonia , which progressed to septic shock on the 36 day of her admission .
she required vasoactive drugs for 2 days at the icu and , unfortunately , her renal function was never fully recovered .
she was discharged from hospital to a hospice care facility with a pedal pulse and no deficit on her limb , though requiring chronic dialysis .
treatment of embolic arterial occlusion with severe limb ischemia is well defined and involves the use of an embolectomy catheter as the best alternative .

co2 has been used electively in both diagnostic and therapeutic procedures in the femoropopliteal tree , and is reported to be safe and non - nephrotoxic .

intraoperative angiography was beneficial because it allowed the diagnosis of the arterial tree occlusion after the initial embolectomy .
additional removal of clots was performed and the result was documented as complete patency of the anterior tibial artery to the foot .
our goal , when using co2 , was to decrease the need for postoperative dialysis .
probably , in this case , the deleterious stimuli ( surgical stress , urinary tract infection and septic shock due to pneumonia ) contributed to renal failure and subsequent need for dialysis . the countermeasure ( such as the use of non - nephrotoxic contrast )
if we had used the iodinated medium , we might wonder if something could have been done differently to avoid dialysis .
we consider co2 to be an alternative to iodine contrast when the decision to perform angiography is made in the acutely ischemic limb . to the best of our knowledge
, this agent has never been described in this clinical setting ; it presents good quality imaging , is not nephrotoxic and does not increase the risk for the limb or the patient in acute arterial occlusions .
this approach may prove to be fruitful in patients with borderline renal function , thereby reducing the risk of short or long - term need for dialysis .
a isquemia aguda de membro de origem emblica  uma situao clnica de carter urgente , em que ocorre uma diminuio ou piora sbita na perfuso de um membro , e configura um risco  viabilidade da extremidade e  vida .
o tratamento consiste em revascularizao imediata com um cateter de embolectomia . a remoo completa de todos os mbolos oclusivos na rvore arterial leva aos melhores desfechos ; por isso
, alguns autores defendem a arteriografia aps a embolectomia , para os membros inferiores .
  a angiografia  tradicionalmente realizada com contraste iodado , mas o dixido de carbono ( co2 ) foi estudado como um agente de contraste intravascular alternativo para pacientes com alergia a iodo ou alterao na funo renal .
como o co2 no  nefrotxico , julgou - se razovel utilizar esse contraste em uma paciente com funo renal limtrofe ( borderline ) que seria submetida aos estmulos nocivos de reperfuso do membro , aps a revascularizao .

em nosso entender , este foi o primeiro caso que avalia o uso intraoperatrio de co2 como um substituto de contraste iodado em um paciente com doena renal crnica conhecida e isquemia aguda de membro .
paciente do sexo feminino , 79 anos , chegou ao pronto - socorro com isquemia aguda no membro inferior esquerdo , com durao de 2 horas .
como antecedentes , apresentava hipertenso , fibrilao atrial e insuficincia renal crnica , no dependente de dilise .
a paciente tinha sido operada 2 anos antes , por ocluso artica aguda de origem emblica , quando foi realizada embolectomia femoral bilateral com cateter .
 alta , os pulsos pediosos eram palpveis , mas os tibiais posteriores eram ausentes , bilateralmente .
a paciente fazia uso irregular dos medicamentos , e o tempo de protrombina ( inr , sigla do ingls international normalized ratio ) era de 1,1 . o pulso estava arrtmico ; era hipertensa ( 160x110mmhg ) e apresentava pulsos femoral , poplteo e distal normais , na perna direita .
 palpao do membro inferior esquerdo , havia apenas um pulso femoral fraco ; os pulsos distais estavam ausentes . a paciente apresentava dor e dfice motor .
ela foi considerada como portadora de isquemia de membro grau iib ( risco eminente ) e foi encaminhada imediatamente para cirurgia .
o clearance de creatinina estava diminudo nos exames pr - operatrios ( cockroft - gault de 12ml / min ) .
sob anestesia geral , foi realizado acesso femoral na cicatriz da inciso anterior do membro inferior esquerdo . as artrias femorais comum , superficial e profunda foram dissecadas e clampeadas .
foi feita arteriotomia e uso de cateter de embolectomia de 4fr ( edwards lifesciences corp , irvine , califrnia , estados unidos ) .
os trombos foram removidos das artrias femorais superficial e profunda . o cateter avanou mais de 60 cm na artria femoral superficial , mas no pde ser palpado . o fluxo retrgrado no foi significativo e decidiu - se realizar uma angiografia para avaliar melhor a rvore arterial infrapopltea .
foi escolhido o co2 como substituto ao contraste iodado para a angiografia . utilizou - se um sistema home - made com fornecimento de co2 em selo dgua , semelhante a outro descrito anteriormente , mas com uma modificao para evitar a contaminao do ar ambiente .
bloomington , indianpolis , estados unidos ) inserido na arteriotomia , quando as artrias foram pinadas .
a figura 1 mostra uma artria popltea e uma fibular prvias , e uma ocluso no tero mdio da artria tibial anterior .
levantamos a hiptese de o cateter de embolectomia ter alcanado a artria fibular na primeira tentativa , e por isso no ter sido palpvel ao exame fsico .

artrias popltea e fibular prvias , ocluso no tero mdio da artria tibial anterior
  realizou - se , ento , nova embolectomia .
o cateter avanou at o p , na topografia da artria pediosa ( isto  , o cateter pde ser palpado na projeo da artria ) e mais trombos foram removidos . a angiografia de
controle ( figura 2 ) mostrou resoluo completa da ocluso da artria tibial anterior , com contraste fluindo at o p ( figura 3 ) .
foram usados 28ml de co2 , e no foi necessrio aplicar o contraste iodado .

resoluo completa da ocluso da artria tibial anterior

 figura 3arteriografia com dixido de carbono .
chegada de contraste na artria tibial anterior at o p
  foi realizada a arteriorrafia . as artrias foram desclampeadas ,
os sinais de isquemia ( palidez e hipotermia ) foram imediatamente resolvidos aps a liberao do fluxo arterial .
a paciente no desenvolveu sinais de sndrome compartimental . a paciente permaneceu na unidade de terapia intensiva ( uti ) at o 11 dia ps - operatrio .
durante esse perodo , no recebeu nenhum agente nefrotxico , como vancomicina ou drogas vasoativas .
aps a alta da uti , desenvolveu infeco urinria , piora da funo renal e uremia .
iniciou dilise no 18 dia ps - operatrio . a paciente teve pneumonia , que evoluiu para choque sptico no 36 dia de internao .
necessitou de drogas vasoativas por 2 dias na uti e , infelizmente , nunca mais recuperou a funo renal .
teve alta hospitalar e foi para instituio de cuidados terminais , com pulso distal sem dfice no membro inferior , mas em dilise crnica .
o tratamento da ocluso arterial emblica com isquemia grave de membro est bem definido , sendo o uso de cateter de embolectomia a melhor alternativa .

o co2 tem sido empregado de forma eletiva tanto nos procedimentos diagnsticos como nos teraputicos na rvore fmoro - popltea , sendo descrito como seguro e no nefrotxico .
  a angiografia intraoperatria foi benfica , j que permitiu o diagnstico de ocluso da rvore arterial aps a primeira embolectomia . mais cogulos foram removidos , e o resultado documentado foi a permeabilidade completa da artria tibial anterior at o p .
nosso objetivo , ao utilizar co2 , foi o de diminuir a necessidade de dilise no ps - operatrio .
neste caso , provavelmente , os estmulos prejudiciais ( estresse cirrgico , infeco do trato urinrio e choque sptico por pneumonia ) contriburam para a insuficincia renal e para consequente necessidade de dilise . a contramedida ( como o uso de contraste no nefrotxico ) poderia ter prevenido a insuficincia renal , se fosse esta uma situao nica .
se tivssemos usado o contraste iodado , pensaramos se algo diferente poderia ter sido feito para evitar dilise .
consideramos o co2 como uma alternativa ao contraste iodado quando  necessria a angiografia para isquemia aguda de membro .
em nosso entender , esse agente nunca foi descrito nessa situao clnica , proporcionando boa qualidade de imagem , no sendo nefrotxico , nem aumentado o risco do membro ou do paciente , em casos de ocluses arteriais agudas .
essa abordagem pode se mostrar til em pacientes com funo renal limtrofe ( borderline ) , reduzindo , assim , o risco de precisar de dilise a curto ou longo prazo .

Answer:
acute limb ischemia can be potentially harmful to the limb and life threatening .
 renal failure is a possible outcome associated with release of products of ischemic limb reperfusion .
 some authors reported the benefit of performing angiography after embolectomy , even though iodine contrast is also nephrotoxic .
 we report a case of embolectomy on a patient with renal insufficiency in whom carbon dioxide was used as a substitute for iodine contrast .