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:
primary stabbing headache is a short duration headache disorder that is characterized by brief paroxysms of sharp head pain often located in the first division of the trigeminal nerve , occurring at an irregular frequency , lacking any accompanying symptoms , and not attributable to any underlying cause .
stabbing headache has also been reported to occur as a symptom of , or in association with , a variety of underlying secondary disorders , including giant cell arteritis [ 2 , 3 ] , pituitary tumors , meningiomas , ocular pathology , ischemic stroke [ 6 , 7 ] , cavernous hemangioma of the frontal bone , and varicella zoster meningoencephalitis .
stabbing headache has not been reported to manifest as a direct consequence of a small well - circumscribed acute brain lesion , and its pathophysiology remains elusive .
herein , a lesional cause of stabbing headache , a small acute thalamic hematoma , is presented .
a 95-year - old right - handed caucasian woman presented to our emergency department with the sudden onset of a constellation of spontaneous neurological symptoms .
she first noted repetitive , sharp , 12  s paroxysms of pain in strictly the right frontal and supraorbital region , occurring dozens of times per hour but at irregular and unpredictable frequencies .
her pain was unaccompanied by photophobia , phonophobia , cranial autonomic symptoms , or any visual changes .
she did not identify any triggers and tactile stimulation of any area of the head or face did not provoke the pain .
these attacks continued until she finally fell asleep in the hospital 12  h later , and upon awakening 6  h later , did not recur .
minutes after the head pain onset , she noted mildly slurred speech , which also resolved by the following morning , and upon attempting to ambulate she felt very imbalanced , which persisted for several days .
her past medical history included hypertension , hyperthyroidism , gastroesophageal reflux , osteoarthritis , and a left intertrochanteric femoral fracture sustained after a fall , which was surgically repaired 4  months previously .
postoperatively she developed cholangitis from choledocholithiasis , an acute pulmonary embolism , and paroxysmal atrial fibrillation , for which she was treated with intravenous antibiotics and placed on long - term anticoagulation .
she had no history of any primary headache disorder , denied ever experiencing any focal neurological symptoms .
her medications included warfarin , fosinopril , omeprazole , metoprolol , digoxin , and methimazole .
she lived with her husband and was a retired school teacher . on review of systems , for several months she had ongoing right upper quadrant pain and occasional nausea that had been attributed to choledocholithiasis .
she denied jaw claudication , episodes of visual loss , myalgias , or neck pain .
her general medical examination revealed a well - appearing woman with normal vital signs , and only mild right upper quadrant tenderness . on neurological examination ,
deep tendon reflexes were 1 + in the arms , trace at the knees , and she lacked ankle jerks .
she had a white blood cell count of 12,000/l , a total bilirubin of 2.3  mg / dl , a direct bilirubin of 1.2  mg / dl , an alkaline phosphatase of 560
u / l , a sgot of 341  u / l , and a sgpt of 292  u / l .
noncontrast computed tomography of the head revealed a rounded hyperdense lesion in the left lateral thalamus abutting the posterior limb of the internal capsule , consistent with an acute small hemorrhage , along with multiple subcortical lacunes and white matter ischemic changes ( fig .  1 ) .
the hematoma volume was estimated to be 0.12  cm using the abc/2 method .fig .
1axial noncontrast computed tomography of the brain revealed an acute , rounded hyperdense lesion in the region of the left thalamus and likely abutting the posterior limb of the internal capsule ( white arrow ) , corresponding to a small acute hemorrhage axial noncontrast computed tomography of the brain revealed an acute , rounded hyperdense lesion in the region of the left thalamus and likely abutting the posterior limb of the internal capsule ( white arrow ) , corresponding to a small acute hemorrhage the patient was administered fresh frozen plasma and vitamin k to reverse her coagulopathy and ultimately had an endoscopic retrograde cholangiopancreatography , where numerous gallstones were removed .
the patient was ultimately discharged to a short - term rehabilitation facility for her imbalance and deconditioning .
the correspondence of the acuity of the clinical syndrome with the radiographic demonstration of an acute hematoma strongly supports its causality , although the lack of magnetic resonance imaging makes the exclusion of other acute lesions slightly less definitive .
a fixed site of stabbing headache may signify an underlying symptomatic cause of the disorder ,   as was the case with this patient .
although a stabbing pain character of headache is not uncommon in association with acute cerebrovascular disease , the diagnosis of stabbing headache has not been well described in this population . in a large prospective series of over 2,000 patients with acute ischemic stroke where headache details were captured at stroke onset
, 20% of the patients described their pain character as stabbing , although the diagnosis of stabbing headache was not mentioned .
pareja and colleagues mentioned the onset of stabbing headache in a patient with an ischemic stroke to the parietal lobe , but did not describe its laterality and relationship to the site of the stabbing head pain .
piovesan and colleagues reported the occurrence of stabbing headache in a delayed fashion after an ischemic stroke in three patients who all likely sustained acute middle cerebral artery territory infarctions .
regarding hemorrhagic stroke , in a large series of 90 intracranial hemorrhage survivors , six patients experienced stabbing headache de novo after intracranial hemorrhage , only one of whom had no premorbid headache history .
acute thalamic hematomas in particular can lead to headache over half the time , but similar to other deep structures do not lead to headache nearly as often as hemorrhage in the posterior fossa or lobar structures . in this patient , stabbing headache resulted from an acute parenchymal brain lesion in the thalamus , a location vital to the processing of pain . more specifically , the location of the hematoma may have encompassed the ventral posteromedial nucleus of the thalamus , a relay center for sensory input from the trigeminal system .
the association of the pain strictly occurring in the right trigeminal distribution with a lesion in the corresponding left thalamus is intriguing .
some authors have proposed the disorder results from spontaneous activation of peripheral nerve branches in the trigeminal or upper cervical distribution [ 14 , 15 ] .
another theory is that patients with stabbing headache have segmental and fleeting disinhibition of central pain pathways [ 14 , 15 ] . perhaps in cerebrovascular disease , such disinhibition occurs in an acute fashion in those patients with contralateral pain to the site of infarction or hemorrhage . in stroke patients with ipsilateral stabbing headache
this report demonstrates an association of an acute thalamic lesion with stabbing headache occurring in the contralateral trigeminal distribution . particularly in an elderly patient or individual taking anticoagulants ,
a small thalamic hemorrhage should be considered in the differential diagnosis of new - onset stabbing headache , even when fleeting .

Answer:
stabbing headache can be encountered in both primary and secondary forms , but has been infrequently reported among patients with stroke , and is not known to be associated with a small well - circumscribed brain lesion . a 95-year - old woman taking warfarin presented with the sudden onset of stabbing headache strictly in the right frontal and supraorbital regions , along with gait imbalance and dysarthria .
 neuroimaging revealed a small left thalamic hematoma .
 this association of an acute thalamic lesion with stabbing headache in the contralateral trigeminal distribution is discussed , along with a brief review of stabbing headache occurring in cerebrovascular disease .


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:
bladder cancer ( bca ) is the fifth most common cancer in the united states . in 2012 , it is projected that 73,510 people will be diagnosed with bca and 14,880 will die from the disease .
muscle invasive bc ( nmibc ) , about 30% of patients will either initially present or later progress to muscle invasive bladder cancer ( mibc ) .
radical cystectomy ( rc ) with urinary diversion ( ud ) is the ultimate curative treatment .
diagnosis of bca in patients aged < 40 years is rare and is extremely rare in patients < 30 years of age .
however , cases of bca have been previously reported in pediatric and young adult patients [ 4 , 5 ] .
our aim is to report our experience with a young adult patient with mibc and review the literature for the natural history and outcome .
a 28year  old caucasian male patient with 10 pack  year smoking history with no family history of bca presented to the emergency department with gross hematuria and left flank pain .
the patient underwent computerized tomography ( ct ) of the abdomen and pelvis without contrast due to an elevated creatinine .
ct showed a 6 cm fungating mass at the left posterior wall of the bladder extending to the left ureteral orifice and left hydronephrosis .
no abnormal laboratory findings were noted except for a serum creatinine of 1.73 mg / dl .
the patient was initially managed by left nephrostomy tube placement and subsequent transurethral resection of bladder tumor ( turbt ) . during cystoscopy ,
multiple large masses originating from the left side of the trigone extending to the prostatic urethra and the right ureteric orifice were noted ( figure 2 ) .
no attempt was made to obtain muscle bites secondary to the large volume of disease .
serum creatinine was 1.6 mg / dl following nephrostomy tube placement . the patient was counseled about the possibility for restaging turbt , rc , and urinary diversion by either ileal neobladder or ileal conduit .
the patient then elected to undergo rc and ileal conduit urinary diversion as the patient had elevated serum creatinine and was reluctant to perform cic .
urothelial carcinoma of the bladder in the first three decades of life is extremely rare .
invasive disease and only 1.7% had high  grade tumor . since the vast majority of young patients with bca present with non
muscle invasive low  grade disease , these patients have lower progression and recurrence rates compared to older patients .
this further suggested that the nature of bca in the younger population is different compared to elderly patients . on the otherhand , yossepowitch and dalbagni found no difference in grade or stage upon comparing 74 patients < 40 years of age to 75 patients > 65 years of age .
however , when focusing on only bca patients diagnosed in the first two decades of life , it is evident that these patients had a relatively indolent behaving bca . nevertheless , aggressive bca has been reported in children  a 31 month old   and a 14 year old .
exposure to polycyclic aromatic hydrocarbons ( pahs ) is responsible for 10% to 15% of cases as a result of bladder carcinogenesis .
genetic predisposition to bca has been suggested by reports of multiple  case families with bca .
however , it is unclear whether it resulted from a genetic predisposition or common environmental exposure among family members . as in elderly patients ,
radical cystectomy is the curative intervention for patients with mibc , recurrent high grade superficial bca , and high  grade t1 disease .
prostate and seminal vesicles sparing rc in addition to nerve sparing procedure can be a valuable option for those patients .
preservation of urinary continence by performing a nerve sparing procedure and orthotopic neobladder urinary diversion is preferred to attain a proper quality of life and body image . in our patient
, ileal neobladder urinary diversion was not performed due to the patient 's unwillingness to perform cic and the fear of chronic renal insufficiency considering the elevated baseline creatinine , ( 1.73 ) which remained elevated ( 1.6 ) following nephrostomy tube placement .
this tendency is more pronounced in patients presenting in the first three decades of life and is likely to decrease with age .
quality of life and fertility preservation is particularly significant in young patients undergoing radical cystectomy and urinary diversion .
our case demonstrates a rare example of a high  grade t2 transitional cell carcinoma in a 28 year male .

Answer:
the peak incidence of bladder cancer ( bc ) is in the sixth decade of life .
 muscle  invasive bladder cancer ( mibc ) in young adults is extremely rare .
 we report a case of mibc in a 28year  old smoking male patient .
 the patient presented with hematuria and flank pain for which he underwent a computerized tomography ( ct ) scan of the abdomen and pelvis with and without contrast .
 the ct scan showed a 6 cm mass on the left side of the trigone extending to the left urteric orifice and left hydronephrosis , but no lymphadenopathy was noted .
 the patient then underwent a left nephrostomy tube placement followed by trans
 urethral resection of bladder tumor ( turbt ) .
 the tumor involved both ureteric orifices and extended to the prostatic urethra .
 complete resection was not feasible .
 pathology showed high
 grade t1 urothelial carcinoma .
 ct scan of the chest showed no distant lung metastasis .
 the patient then elected to undergo radical cystectomy with ileal conduit urinary diversion .
 final pathology revealed t2a n0 urothelial carcinoma of the bladder .
 our aim is to present our experience and review the literature for the natural history and oncological and quality of life outcomes of urothelial carcinoma of the bladder in young patients .


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 numerous industrial countries , cerebro - vascular accident ( cva ) has been the third common cause of death after coronary arteries diseases ( cad ) and cancers .
several studies have indicated that higher levels of inflammatory biomarkers such as c - reactive protein ( crp ) and interlukin-6 ( il-6 ) have been associated with worsening ischemic events .

crp is a systemic inflammatory marker that is produced in a large amounts by hepatocytes in response to il-1 , il-6 and tnf factor .
rapid induction of crp , its long half - life ( 19 hours ) and lack of alteration during day and night in comparison with other acute phase reactants has introduced crp as an important factor for evaluation in inflammatory and infectious diseases .
nowadays , crp is a confirmed diagnostic marker for the patients with cva and recent prospective investigations showed that crp is clinically helpful for predicting the risk of the next cardiovascular diseases .
although many studies have been conducted on association of crp and cardiac diseases ; only few studies have evaluated its role in predicting mortality in stroke patients . in addition
, it can be used as biomarker at early phases in diagnosis of stroke , determining prognostic value of therapeutic programs and secondary prevention strategies . in this study
, we intended to evaluate association of crp as an inflammatory marker with acute cerebral ischemic attack characteristics , risk factors and to determine a cutoff point of hs - crp in predicting early mortality .
this study was conducted on 200 patients with impression of stroke who had been referred to emergency ward of university hospital , imam khomeini hospital , tehran , iran , within may 2009 march 2011 .
patients who had referred earlier than 24 hours after ischemic stroke were enrolled in the study .
38 patients with body temperature higher than 37.8 c , hemorrhagic stroke and those with previous inflammatory or malignant diseases were excluded .
medical history was taken from the patient or his / her relatives if the patient was unconscious or not able to speak .
patients were evaluated for age , sex , diabetes , hyperlipidemia , ischemic heart diseases , smoking and past history of stroke or hypertension .
routine laboratory tests , brain magnetic resonance imaging ( mri ) , transthoracic echocardiography ( tte ) and carotid doppler ultrasonography were done in all of the patients .
national institutes of health stroke scale ( nihss ) was used for assessing stroke severity .
type of stroke was determined based on toast ( trial of org 10172 in acute stroke treatment ) classification .
it is able to demonstrate various types of acute ischemic stroke with different etiology and is consisted of 5 sub - groups : large - vessel atherosclerosis , cardioembolic , small - vessel occlusion or lacunar , undetermined etiology , and non - atherosclerotic determined etiologies .
another sample for specific tests was stored in room temperature for 20 minutes until clotting .
serum was stored in -70 c and sent to heart center hospital of tehran university of medical sciences and hs - crp concentration was determined by turbidimetry method and roche kit ( manufactured in swiss ) with using cobaf apparatus ( model integra400 + ) .
usa ) using chi - square test and student 's t - test for univariate analysis and mantel hansel analysis for multivariate analysis .
receiver operating characteristic ( roc ) curve was drawn for demonstrating cut off point of crp for predicting patients mortality within the first week of admission .
they had been referred to emergency ward of imam khomeini hospital within may 2009march 2011 .
mean age of the patients was 67  12 years with a range of 33 - 95 years .
patients were classified into 3 age groups : 11 patients were younger than 50 years ( 6.8% ) , 81 cases were 50 - 70 years ( 50% ) and 70 patients were older than 70 years ( 43.2% ) .
clinical demographic evaluation showed hypertension in 77 ( 47.5% ) patients , diabetes in 50 ( 30.9% ) , hyperlipidemia in 56(35% ) , history of cardiovascular diseases in 46(24.8% ) , history of previous cva in 33(20.4% ) and cigarette smoking in 67(41.4% ) patients .
mean of nihss score was 9.5  8 ( min 1 and max 30 ) . according to nihss score ,
our patients were classified to 3 sub - groups : nihss score < 7 ( mild neurologic disorders ) , nihss score 7 - 13 ( moderate neurological disorders ) and nihss score > 13 ( severe neurological disorders ) . according to toast classification criteria , large vessel atherosclerosis was seen in 95 subjects ( 58.6% ) , cardioembolic in 11 ( 6.8% ) and small vessel occlusion in 56 patients ( 35% ) .
regarding roc curve analysis , appropriate cut - off point for predicting patients short time mortality was determined as 2.15 in this study .
in addition , nihss > 10 was considered as appropriate score for predicting patients short - term mortality ( fig .
roc curve of variables for predicting mortality in the patients with stroke association between hs - crp and early mortality in the patients with acute cva was significant .
mean of crp in died patients was 8.9  7 mg / dl and in survived patients was 2.2  5 mg / dl ( p = 0.0001 ) .
the hs - crp amounts showed a significant association with early mortality , diabetes , ihd ( ischemic heart diseases ) , smoking and nihss .
incidence of early onset mortality based on sub - groups of evaluated demographic variables in the investigated patients with acute ischemic stroke nihss : national institutes of health stroke scale ; rr : relative risk ; crp : c - reactive protein after multivariate analysis and adjusting for sex , age , history of heart disease , nihss score and toast , we found hs - crp as an independent factor in predicting early onset mortality .
significantly increased rate of mortality by 13.3 times was seen in patients by simultaneous crp > 2.15 and nihss > 10 as cut - off points for predicting mortality , so that out of 23 patients possessing these conditions 11(47.8% ) died . in the patients who had simultaneously crp > 2.15 ,
neurological defect severity was more than 10 and diabetes and mortality rate increased about 19 times ; so that out of 13 patients possessing these conditions , 10(76.90% ) died .
therefore , co - existence of these three factors in a patient may strongly increase the risk of mortality .
determinant criteria for mortality risk in the patients with cva and comparing them with each other are summarized in table 2 .

comparing of multivariate factors with early death in the patients with stroke nihss : national institutes of health stroke scale ; rr : relative risk ; crp : c - reactive protein
the results of present study showed that hs - crp in the patients with acute ischemic cva who had died within the first week after manifesting symptoms was significantly higher than survived patients .
in addition , hs - crp levels more than 2.15 mg / dl were considered as cut - off point for predicting mortality in this study .
in addition , a large number of previous studies have reported that increasing crp at the first hours after stroke was associated with risk of mortality .
montaner et al . introduced crp as a powerful factor for predicting mortality after cva .

ischemic damage to brain resulted in disturbance in neuroglia activity especially astrocytes adhered to endothelial .
therefore , these cells release cytokines and inflammatory factors that resulted in neuron necrosis and vessels endothelial permeability . at the same time by impaired blood brain barrier ( bbb )
permeability , neutrophils by exiting through endothelial cells , enters into tissues and increase inflammatory markers concentration . as a consequence ,
it is considerable that numerous articles recommend application of nihss system for more accuracy in stroke severity .
  cut - off point of > 10 for nihss was shown in present study that in combination with an elevated crp > 2.15 was associated with 13 times increase in mortality .
similarly , studies performed by basic et al . and shenhar et al . showed association of nihss and increase in inflammatory factors .
neurological defect severity and its association with elevated crp were shown in ischemic cycles so that more ischemia resulted in more neurological defect severity . among 16 dead cases , 14 ( 30.4% )
patients had history of heart diseases and significant association was seen between hs - crp and mortality in relation to ischemic heart disease .
in addition , a meta - analysis study indicated that crp is directly associated with ischemic heart diseases , stroke and mortality risk .

time of hs - crp evaluation was a determining factor in early predicting mortality in this study .
maximum of plasma crp concentration has been usually reported within 36 to 48 hours after initiating signs of stroke .
a study by winbeck et al . showed that the most appropriate time for obtaining blood samples was 12 - 24 hours after initiating signs and can predict the risk of cardiac and cerebral vascular events . in the present study ,
this study showed that there was a direct association between hs - crp and mortality within the first week after stroke .
cut - off point of crp was 2.15 mg / dl and measuring hs - crp within the first hours after stroke increase the predicting rate of early mortality risk .
as up to now , a blood biomarker that can introduce accurate information about cause and outcome after stroke has not been known yet , cut - off point of hs - crp can be used for therapeutic decision making .

Answer:
backgroundhigh sensitive c - reactive protein ( hs - crp ) is a systemic inflammatory marker that is produced in a large amount by hepatocytes in response to interleukin-1 ( il-1 ) , il-6 and tumor necrosis factor after ischemic stroke.methodsmeasurement of hs - crp in the first 24 hours of onset in 162 patients suffering from ischemic stroke was done .
 relation of crp with the risk of early mortality , national institutes of health stroke scale ( nihss ) , stroke subtypes and other factors was determined.resultsregarding to roc curve analysis , appropriate cut - off point for predicting patients short time mortality was equal to 2.15 mg / dl in this study .
 significantly increased rate of mortality by 13.3 times was seen in patients with simultaneous crp > 2.15 mg / dl and nihss > 10.conclusionthe result of this study showed that there is a direct association between hs - crp and mortality within the first week after stroke .
 measuring hs - crp within the first hours after stroke increases the predicting rate of early mortality risk with cut - off point of 2.15 .


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:
vascular complications after a total knee arthroplasty ( tka ) occur in less than 0.5% of cases.1 it is uncommon , with a reported incidence following tka ranging from 0.03 to 0.17%.27 however , when such a complication does occur , it is potentially limb and life threatening .
popliteal artery pseudoaneurysm is one of the sequelae of popliteal artery trauma and also can cause arterial thrombosis , arteriovenous fistulae , or arterial severance.26 we report a case of a false aneurysm of the popliteal artery after a tka with unusual presentation , difficult diagnosis and successful management .
right tka was done using mobile - bearing knee prosthesis ( depuy , warsaw , indiana , usa ) [ figure 1a and b ] .
postoperative rehabilitation was started on the 1 postoperative day and consisted of static exercises and continuous passive motion .
for postoperative analgesia , iv fentanyl patient controlled analgesia ( pca ) dose 1.5 ml / h , along with intravenous paracetamol ( 1 g ) thrice daily was used . on the 3 postoperative day
, she was disoriented , agitated , and had a fall while trying to get up from bed .
the passive range of motion ( rom ) was not affected following fall and there was no increase in swelling or hematoma formation .
disorientation continued , and on the 4 postoperative day , she had accidental fall again .
she gave a significant history of direct blunt injury to the popliteal fossa with the railing of the bed .
hemoglobin dropped from 8.4 gm% ( 1 postoperative day ) to 6.7 gm% , and she was given packed blood cells .
( a ) postoperative anteroposterior ( a ) lateral ( b ) view x - ray of right total knee arthroplasty showing implant in situ on the 6 postoperative day , patient complained of swelling and severe pain in her calf , refusing to move her right lower limb . swelling extended from popliteal fossa up to midcalf region and was nonpulsatile .
venous doppler examination of the right lower limb was done , which showed no evidence of dvt . while doing the venous doppler , the radiologist suspected an arterial injury .
the arterial doppler showed a pseudoaneurysm of the right popliteal artery , of size 3.9  2.6 cm , with hematoma collection extending into calf [ figure 2a and b ] . computed tomography ( ct ) angiography
was done for further evaluation and suggested extensive wall calcification of the abdominal aorta and iliac arteries .
a 3  2.5 cm pseudoaneurysm in relation to the right popliteal artery just above the knee joint was seen [ figure 3a ] .
( b ) color doppler imaging popliteal artery flow pattern across the pseudoaneurysm ct scan with arrow showing location of pseudoaneurysm ( posterior ) ct angiography of both lower limbs with distal runoffs and good vascularity vascular surgeon opined the need for repair of the rent in the artery causing the aneurysm . a repeat ultrasonographic examination done the next day did not show any increase in the size of the aneurysm .
considering the location of false aneurysm , the vascular surgeon decided to go posterior . on exploration , there were significant clots and the rent was found on the posterior surface of the artery of size 2  2 mm .
the rent was not on the anterior aspect , indicating that the injury to the artery was as a result of the impact on the popliteal region due to a fall in the immediate postoperative period and not an intraoperative incident as is seen in most of the reported cases of popliteal pseudoaneurysm following tka .
after 12 months , the patient remained asymptomatic without any vascular problems . on followup ,
she had well felt distal pulsations without any clinical evidence of pulsatile swelling in popliteal area .
trauma to popliteal artery in tka is an intraoperative event . it can present as an acute arterial severance or with arterial thrombosis , pseudoaneurysm , arteriovenous fistula , and occlusion.26 pseudoaneurysm of the popliteal artery is one of the uncommon arterial complications which may present early as a pulsatile mass in the popliteal fossa or remains undetected for a long time.236 it can present as a painful calf swelling as in dvt.5 occasionally , it may present very late.7 the reported mechanisms of injury are due to direct trauma to the vessel , like posterior retractor , oscillating saw or pins used to hold the tibial jig , posterior capsular release.26 the diagnosis of a post tka popliteal artery pseudoaneurysm should be suspected clinically , and diagnostic tools such as doppler ultrasonography and ct angiography should be used to confirm the diagnosis.1516 repeat ultrasonography is also valuable in determining whether the aneurysm is increasing in size .
smaller pseudoaneurysms which are associated with small defects in the arterial wall can be treated with ultrasound guided compression repair ( ugcr ) .
this procedure involves two sittings , week apart , by applying compression at the neck of pseudoaneurysm .
compression is performed with the us transducer itself , a procedure that permits direct and continuous visualization of the vessels .
typical protocol includes an initial 10 - 20-min compression of the pseudoaneurysmal neck ; if this is not feasible , the pseudoaneurysm itself is compressed .
anticoagulation therapy decreases the success rate ; therefore , anticoagulants should be discontinued prior to the procedure if possible . drawbacks of this procedure are long procedure time , discomfort to the patient , recurrence , and rupture of aneurysm .
however , due to the nature of the trauma , only a small proportion of these lesions are amenable to percutaneous therapy which is fairly superficial pseudoaneurysm with less hematoma and commonly used for femoral , axillary , and brachial artery pseudoaneurysms.1416 the established treatment for the remainder is open repair with or without popliteal artery bypass grafting with ligation of the native artery .
open repair has its own set of difficulties as it involves operating from a posterior approach and exposing the recently placed prosthesis to infection .
endovascular treatment involves placement of a covered stent across the defect in the popliteal artery.11316 though no long patient series is available , evidence suggests that endovascular treatment is safe and durable as a treatment modality in the treatment of traumatic popliteal artery pseudoaneurysms and can be performed with an acceptable morbidity rate .
all reported pseudoaneurysms of popliteal artery or inferior geniculate artery are on anterior aspect and due to intraoperative direct injury to the vessel with varied presentation.27 though popliteal pseudoaneurysm is rare , it can be a devastating complication post tka .
we hereby reported an exceptional case where there was trauma to the popliteal fossa due to a fall in the immediate postoperative period probably due to disorientation caused by the use of iv fentanyl and the location of arterial rent was on posterior aspect .
the clinical presentation of this condition can be confused with that of a postoperative dvt or hematoma formation in early postoperative period and the surgeon should be aware of this condition .
the treatment options include an open surgical repair or other described noninvasive techniques such as percutaneous embolization or endovascular stenting .

Answer:
we report a case of posttraumatic false aneurysm of popliteal artery after a total knee arthroplasty in an 82-year - old woman .
 this case is characterized by the distinct history of trauma to the popliteal fossa in the immediate postoperative period and the location of false aneurysm . in addition , the clinical symptoms were similar to those of deep vein thrombosis . the ultrasonographic examination and computed tomography ( ct ) angiography confirmed the diagnosis on 6th day after the surgery .
 ultrasonographic examination 1 day later revealed no increase in the size of false aneurysm .
 she was treated with open surgical repair .
 presenting the difficulty in the diagnosis , unusual location , etiology , and its management is the intention of this case report .


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:
carbapenem resistant gram - negative bacteria ( gnb ) such as enterobacteriaceae ( cre ) ( including escherichia coli [ crec ] and klebsiella pneumoniae [ crkp ] ) , pseudomonas aeruginosa ( crpa ) and acinetobacter baumanni ( crab ) are important emerging causes of nosocomial blood stream infections and carry significant mortality .
 urgent threat  by the us centers for disease control and prevention ( cdc ) , while the antimicrobial availability task force formed by the infectious diseases society of america had identified crpa and crab of particular importance , because of growing antimicrobial resistance among these isolates and shrinking therapeutic options .
indian single center studies overall report a prevalence of carbapenem resistance in up to 12 - 15% of enterobacteriaceae and 40 - 60% in a. baumanii and p. aeruginosa .
however , there is little data from india about the clinical profile and treatment outcome of infections caused by these organisms .
this was a retrospective study performed at a 600 bed tertiary care facility in chennai , india between may 2011 and may 2012 .
we identified all blood culture results that had yielded a growth of carbapenem - resistant gnb during the study period .
blood cultures were performed using bact / alert ( biomerieux ) culture system , and species ' identification was carried out with vitek - gni card ( biomerieux ) .
antibiotic susceptibility was performed using disc diffusion interpretive criteria as per revised clinical and laboratory standards institute performance standards .
gram - negative bacteremia was defined as the isolation of gram - negative bacilli in blood culture specimen in at least two bottles of two different culture sets with clinical features compatible with systemic inflammatory response syndrome .
clinical parameters analyzed included severity of illness as calculated by acute physiology and chronic health evaluation ( apache ) ii score on the day of bacteremia onset , presumed source of infection and presence of arterial and venous central catheters or hemodialysis catheters .
the source of bacteremia was defined on the basis clinical and microbiologic evaluation using infections criteria proposed by cdc .
presence of risk factors such diabetes , recent surgery , organ transplant and immunosuppression were recorded .
prior antibiotic usage , dose of colistin and requirement for renal replacement therapy ( rrt ) after treatment with colistin commenced were also noted .
the records of 50 patients with bacteremia caused by crec , crkp , crab , crpa were identified and analyzed .
the mean age of patients was 52.3 years and 32 ( 64% ) were male .
the most common co - morbid condition was diabetes mellitus ( 30% ) , followed by chronic kidney disease ( 22% ) .
the total mean duration of hospitalization was 24.68 days with a mean of 11.76 days of intensive care unit ( icu ) care . the mean time to onset of bacteremia was 6.4 days after admission .
of the 50 patients , 96% had already received antibiotics , including beta - lactam / beta - lactamase inhibitors ( 32% ) and carbapenems ( 40% ) [ table 1 ] .
the mean (  standard deviation [ sd ] ) apache ii score at the onset of bacteremia was 19.64  3.8 .
thirty - eight percent ( n = 19 ) patients had septic shock complicating bacteremia .
fourteen episodes ( 28% ) of bacteremia were attributed to ventilator - associated pneumonia ( vap ) , 12 episodes ( 24% ) to the central line related bloodstream infections ( clabsi ) , 10 episodes ( 20% ) were due to intra - abdominal infections ( iai ) and 9 episodes ( 18% ) to urinary tract infections .
the most common causative organism in our study was crkp ( 44% ) followed by crec ( 26% ) , while crab and crpa were isolated in 20% and 10% patients respectively [ table 2 ] .
observed outcome of patients all patients received a loading dose of colistin with a mean of 5.14 million units intravenously followed by a mean 5.18 million units total daily dose .
mean creatinine clearance ( calculated estimated glomerular filtration rate [ egfr ] ) at the initiation of colistin was 52.48 ml / min .
six patients ( 12% ) required rrt after initiation of colistin for worsening renal functions ; all recovered to normal renal function .
the overall survival at 30 days was 40% in our study with lowest survival rates for clabsi ( 33.3% ) , with survival rates for vap , iai and urosepsis patients of 35.7% , 40% and 44.4% respectively .
overall 30 days survival for crab and crkp bacteraemia were lowest ( 30% and 31.8% respectively ) , while survival rates for crpa and crec bacteraemia were 40% and 61.5% respectively .
we also found that patients treated with combination therapy had lower mortality ( 44.8% ) compared with colistin monotherapy ( 66.6% ) although this was statistically not significant ( p = 0.35 ) [ table 3 ] .
carbapenem resistance in gram - negative organisms is increasingly encountered in healthcare - associated infections in india .
bacteremic episodes due to these organisms carry a high mortality as shown by previous studies from other countries . in our study , the most common carbapenem
resistant gram - negative isolate was crkp ( 44% ) followed by crec ( 26% ) with more than half of all episodes due to pneumonia or clabsi , similar to two previous indian studies presented as abstracts in scientific meetings .
our patients had a high apache ii score ( 19.64  3.8 sd ) and had a mean icu stay of 11.76 days , with a mean time of onset of bacteremia after admission of 6.4 days .
these results are in concordance with previous studies implicating these organisms as causes of healthcare - associated infections .
seriously ill - patients in icus for prolonged periods often require central lines , dialysis catheters , broad spectrum antibiotics , and mechanical ventilation , which make them susceptible to resistant hospital - acquired infections .
notably only 40% of our patients had received carbapenems , but virtually all had antibiotic exposure , suggesting that healthcare exposure and overall prior antibiotic exposure may be more important risk factors for developing carbapenem resistant infections rather than prior receipt of carbapenems .
colistin has emerged as the cornerstone of therapy for carbapenem - resistant gnb , but the correct dose and frequency of dosing is a subject of on - going study .
the mean colistin loading dose in our study was only 5.14 million units followed by mean total daily dose of 5.18 million units intravenously , even with a mean egfr of 52.48 ml / min at colistin initiation .
use of low colistin doses may be because of a perceived concern about nephrotoxicity ; our study period was also prior to evolution of new colistin dosing recommendations . in our study , six patients ( 12% ) required new onset rrt due to worsening renal functions after colistin initiation but this was fully reversible with dosing adjustments , which was reassuring and similar to other studies .
the overall 30 days survival rate in our cohort was only 40% , but it was difficult to assess whether this was due to sepsis itself or due to underlying severe illness and multiple co - morbidities .
mortality in our patients was highest when clabsi or vap was the source of bacteremia and when crab and crkp were the causative organisms .
better survival rates from the west have been reported , but similar results to ours have been observed in two previous indian abstract presentations .
higher colistin doses are associated with higher microbiologic clearance and reduced mortality at 7 days although 28 days mortality did not differ .
it is also possible that relatively low dose our patients received may have contributed to mortality .
we also observed that patients treated with two drug combinations had a trend towards a higher survival rate than those treated with colistin monotherapy , as observed in other studies also .
small study numbers in the two groups and the fact that more severely ill patients may receive combination treatment , may have resulted in the absence of a statistically significant difference .
we acknowledge significant limitations in our study : its retrospective nature , relatively small sample size and absence of a control group for comparison .
we have shown that carbapenem - resistant gram - negative bacteremia is a serious healthcare - associated infection in critically ill - patients in indian icus with co - morbidities and prior antibiotic exposure ; k. pneumoniae is the most common organism at our center .
thirty days survival rate is only 40% and even lower for clabsi or vap or when due to a. baumanii or k. pneumoniae .
colistin is the cornerstone of therapy and may need to be studied at higher doses to optimize the outcome ; nephrotoxicity requiring rrt was seen in 12% of patients only and was reversible in all .
combinations of other antibiotics with colistin may result in a lower mortality compared with monothrapy , however this needs needs to be explored through a randomized controlled study

Answer:
background : growing antimicrobial resistance and limited therapeutic options to treat carbapenem - resistant bacteremia prompted us to evaluate the clinical outcomes associated with healthcare - associated bacteremia.methods:this was a retrospective observational study of carbapenem - resistant gram - negative bacteremia performed at a tertiary care facility in chennai , india between may 2011 and may 2012.results:in our study , patients had mean 11.76 days of intensive care unit ( icu ) care and mean time to onset of bacteremia was 6.4 days after admission .
 the commonest organism was klebsiella pneumoniae ( 44% ) .
 patients with combination treatment had lower mortality ( 44.8% ) compared with colistin monotherapy ( 66.6% ) ; ( p = 0.35).conclusion : carbapenem resistant bacteremia is a late onset infection in patients with antibiotic exposure in the icu and carries a 30 days mortality of 60% ; k. pneumoniae is the most common organism at our center .
 two drug combinations appear to carry a lower mortality compared with monotherapy .


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:
bone marrow is the major hematopoietic organ . bone marrow hematopoietic tissues are highly sensitive to toxins , including radiation and chemotherapeutics , which may induce myelosuppression .
the cytoactivities of primitive hematopoietic cells may , therefore , be depressed , and the number of peripheral blood cells may decrease substantially .
in addition , severe myelosuppression may cause infections , inflammation , and bleeding [ 1 , 2 ] .
it is generally accepted that maintenance of normal hematopoiesis relies on the stabilization of the hematopoietic microenvironment . as the major component of this microenvironment ,
hematopoietic cytokines play a key role in the regulation of hematopoiesis , controlling the proliferation , differentiation , and maturation of primitive hematopoietic cells [ 3 , 4 ] .
il-6 is a kind of cytokine with a wide range of biological activities , produced mainly by t and b lymphocytes , monocytes , fibroblasts , and so forth [ 5 , 6 ] .
recent studies showed that il-6 involved not only in the progress of the stress reaction , autoimmune , and neoplastic diseases of the body but also in regulation of the proliferation and differentiation of primitive hematopoietic cells , and it is considered as a permissive factor of primitive hematopoiesis .
of all the cytokines , il-6 is the first one found to be associated with the pathogenesis of the disease , due to its close relation with a variety of diseases under overexpression .   in the present study , a mouse model of aplastic anemia
was established by using cyclophosphamide in combination with chloramphenicol and co radiation . after modeling ,
the in vitro proliferation of bmsc was tested by mtt assay , and the il-6 secretion levels of bmsc were analyzed .
this study gives new insights into the hematopoiesis regulating properties of il-6 in mice with aplastic anemia .
the procedures of our experiment are in compliance with the principles of laboratory animal care .
imdm tissue culture media and il-6 elisa kits were purchased from the jingmei company ( chengdu , china ) .
the tunel kit was purchased from the boster company ( wuhan , china ) . the fully automatic blood cell analyzer ( hs-18 )
was made in italy ; the inverted phase contrast microscope by the chong qing optical instrument factory ( china ) ; the co2 incubator ( mcd-15a ) in japan ; and the fully - automatic elisa meter by the thermo company ( usa ) .
healthy balb / c male mice , weighing 1822  g , aged 68 weeks , were provided by the experimental animal center of chengdu university of traditional chinese medicine .
animals were housed in a warm , quiet environment with free access to food and water .
the radiation source ( co ) was provided by sichuan academy of agricultural sciences .
briefly , the mice were irradiated with 2.0  gy co and then treated with daily intraperitoneal injections of cyclophosphamide at 40  mg / kg / day and chloramphenicol at 50  mg / kg / day for the next three days .   on day 7 after modeling ,
20  l blood was taken from the orbital vein of the mouse and diluted with the manufacturer recommended diluent before analysis with the hs-18 fully automatic blood cell analyzer .
eight mice from each group were sacrificed , and the femurs of each mouse were removed .
the bmc suspension was prepared according to zhang 's method , and the number of bmc was counted . on day 7 ,
two mice from each group were randomly chosen , the femurs and spleens were removed , fixed in 4% neutral formalin , decalcified , and desiccated , and embedded in paraffin , and then semithin sections were cut .
after hematoxylin - eosin staining , the pathomorphological changes of bone marrow and spleen were observed with a light microscope . on day 7 , bmc smears were prepared , and bmc apoptosis was analyzed by tunel , according to the specifications of the tunel kit .
5 microscopic fields of each slide were randomly chosen and observed under microscope , and the apoptosis ratio was calculated .
on the 4th , 7th , and 10th days after modeling , bmc suspensions were prepared as described above then adjusted to a concentration of 1  10  cells / ml .
bmc were cultured in imdm supplemented with 15% fetal calf serum at 37c in 5% co2 and saturated humidity . after 48  h of cultivation , culture supernatants were harvested and stored at 20c for il-6 analysis .
mtt was added to every well , and the culture medium was put back to the incubator .
4  h later , the mtt was removed and the cells were washed by pbs twice . 100  l of isopropyl alcohol was added to split the cells . then , the enzyme - linked immunosorbent assay was used at the 570  nm to detect the a value of every well .
all data were expressed as mean  standard deviation ( x-s ) , and the t - test was used to evaluate the difference between groups , with p < 0.05 considered to be statistically significant .
as measured by the fully automatic blood cell analyzer , the number of peripheral blood cells in the aplastic anemia mouse model was notably decreased ( p < 0.05 ) . besides , the number of bmc was markedly decreased ( p < 0.05 ) .
these data indicated that the aplastic anemia model had been successfully established ( figure 1 ) .
the morphology of the bone marrow tissue had changed obviously after modeling . in our model ,
the amount of hematopoietic tissue , as well as the number of hematogenous cells in bone marrow , was obviously reduced .
the number of lymphocytes , fat cells , and other nonhematogenous cells , however , increased markedly .
these changes were accompanied by interstitial edema and blood sinus expansion ( figure 2 ) .
the spleen atrophied , the splenic corpuscle shrank or disappeared , and its structure was clearly compromised .
spleen blood sinuses dilated , hematopoietic focus disappeared , and megakaryocytes decreased or were absent ( figure 3 ) .
the apoptosis rate of bmc from the aplastic anemia group ( 9.75  2.43% ) was significantly higher than that of normal controls ( 3.63  1.06% ; figure 4 ) ( p < 0.05 ) .
nuclei of the apoptotic bmc were stained red with fast red while nuclei of nonapoptotic bmc were stained blue with hematoxylin ( figure 5 ) .

figure 6 showed that at the three time points ( 4th day , 7th day , and 10th day ) , the level of il-6 in cultured supernatants of bmsc from the anemia group was significantly higher than that of the normal group ( p < 0.05 ) .
bmsc displayed long fusiform shape under invert phase contrast microscope cultured more that 2 days ( figure 7 ) .
the a value of model group at the three time points ( 4th day , 7th day , and 10th day ) was significantly lower than that of normal group ( p < 0.05 ) ( figure 8) .
it has many target cells including macrophages , liver cells , stationary t cells , activated b cells , and plasma cells .
it can play important roles in the acute phase of the immune response , hematopoietic regulation , and other processes .
recent studies also found that il-6 can stimulate the formation of myeloid , erythroid , megakaryocyte , and macrophage cloning , in combination with epo , il-3 , and other hematopoietic cytokines .
as il-6 has important functions in proliferation , differentiation , and maturation of early hsc , it is considered as a permissive factor of primitive hematopoiesis .
defective bone marrow stroma , or microenvironment , has been proposed as one of several mechanisms to account for bone marrow failure .
this could involve defects in positive- or negative - acting hemopoietic regulator expression by stroma or alteration of normal stroma - stem cell interactions . as the permissive factor of primitive hematopoiesis ,
the role of il-6 in the bone marrow hematopoiesis disorder has been subject of intense attention in recent years .
so far , the precise mechanism of il-6 in hematopoiesis regulation still remains largely unclear . in the present study , a mouse model of aplastic anemia
was established by using cyclophosphamide in combination with chloramphenicol and co radiation . after modeling ,
the peripheral blood cells and bmc were significantly reduced and the apoptosis of bmc was obviously increased . decreased hematogenous cells and increased fat cells in the bone marrow of the mouse model were easily observable with a microscope .
furthermore , the spleen shrank , the splenic sinus was enlarged , and the hemopoietic focus were evidently reduced .
these results demonstrated that the bone marrow hematopoietic function was severely injured , and the mice model was successfully constructed .   to investigate the level of il-6 secreted by bone marrow stromal cells from the mouse model of aplastic anemia , in the present study , in vitro cultivation of bone marrow stromal cells was employed , and the il-6 level was measured with elisa .
the result showed that at the three time points ( 4th day , 7th day , and 10th day ) , the level of il-6 in cultured supernatants of bmsc from the anemia group was significantly higher than that of the normal group , which indicated that the il-6 secretion level may be enhanced to some extent by the induction of aplastic anemia caused by irradiation and chemotherapeutic drugs .
as a cytokine with a wide range of biological activities , il-6 has very complex functions .
it is a key component of the inflammatory mediator network , with an important role in the inflammatory response . as an anti - inflammatory cytokine
however , il-6 is also a proinflammatory factor and , when overexpressed , can lead to a variety of diseases .
significantly elevated il-6 levels were detected in the serum of rheumatoid arthritis , diabetes , acute pancreatitis , hiv , and cancer patients [ 1316 ] .
herodin et al . reported that in radiation - induced bone marrow depressed baboons , a substantial precocious and transient il-6 blood release was detected within hours after irradiation .
the origin of the precocious transient il-6 peak observed just after irradiation was not clear .
it was supposed that the increase of il-6 may be caused by a more precocious il-1 and/or tnf release . in a clinical experiment ,
fu et al . found that the pretreatment level of il-6 in serum and bone marrow of 37 aplastic anemia patients were slightly higher than that of normal control , but there was no significant difference between the aplastic anemia group and the normal control group .
supposed that the change of il-6 level in aplastic anemia patients may be due to an association with inflammatory response , and il-6 may have an effect of immunoregulation and mediate induction in the destruction pathology of bone marrow cells , but the concrete mechanism still needs to be elucidated . in our study , we noticed that in the anemia group , with the increase of il-6 level , the proliferation of the bmsc was obviously impeded .
this result indicated that high level of il-6 might be harmful to the proliferation of bone marrow stromal cells and might interfere with the stability of the bone marrow hematopoietic microenvironment . as the main component of the bone marrow hematopoietic microenvironment , bmsc adhere to hematopoietic stem cells , support and regulate the internal environment for the settling , differentiation , proliferation , and maturation of the primitive hematopoietic cells , and secrete a variety of cytokines to regulate hematopoiesis ; therefore , defects of the bone marrow stromal cells can cause hematopoietic disorders of the bone marrow [ 19 , 20 ] .
the results of our study suggested that the il-6 secretion level may be enhanced to some extent by the induction of aplastic anemia caused by irradiation and chemotherapeutic drugs and that the abnormal level of il-6 might probably interfere with the stability of the bone marrow hematopoietic microenvironment .
currently , the role of il-6 in the regulation of hematopoiesis process and the specific mechanism remain unclear , so further investigations are needed .

Answer:
parasecretion of the hematopoietic cytokines is considered as one of the mechanisms account for bone marrow hematopoiesis disorder . in this study , the level of il-6 secreted by bone marrow stromal cells from a mouse model of aplastic anemia was analyzed .
 the aplastic anemia mouse model was established with cyclophosphamide in combination with chloramphenicol and 60co radiation .
 the impairment of bone marrow hematopoiesis induced by irradiation and chemotherapeutic drugs was subsequently characterized by peripheral blood cell count , pathomorphological changes , and apoptosis rate .
 furthermore , the in vitro proliferation of bone marrow stromal cells ( bmsc ) and the il-6 secretion levels of bmsc were analyzed . in our model of aplastic anemia ,
 the number of peripheral blood cells and bone marrow cells ( bmc ) were notably decreased , and the apoptosis rate of bmc increased .
 furthermore , the proliferation of bmsc was obviously impeded while the il-6 secretion levels of bmsc significantly increased .
 the findings of our study suggested that the il-6 secretion level may be enhanced to some extent by the induction of aplastic anemia caused by irradiation and chemotherapeutic drugs and that the abnormal level of il-6 might probably interfere with the stability of the bone marrow hematopoietic microenvironment .


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:
it is predicted that by 2025 , the prevalence of hypertension ( htn ) will increase by 60% to a total of 1.56 billion worldwide   suggesting that htn remains a major public health problem .
htn in sub - saharan africa ( ssa ) has also been on the rise with reports indicating higher values in urban settings compared to rural settings [ 24 ] .
the prevalence of htn in ssa ranges between 14.5% in rural eritrea , 32.9% in semiurban ghana , and 40.1% in urban south africa .
likewise , adequate blood pressure ( bp ) control has been on the decline , ranging between 1.7% in rural ghana , 4% in urban slum dwellers in nigeria , and 21.5% in urban kenya . in cameroon
, the prevalence of htn spans from 5.7% in rural settings   through 21.9% in semiurban   to 47.5% in urban milieu , with a national average survey of 31.0% . despite the relatively better bp control in urban over rural settings , levels of adequate bp control as low as 2%   to 27.5% ( in men ) and 38.7% ( in women )
even though much has been done so far to reduce the incidence of hypertension in urban areas , this has not been the same in rural areas , with public health policies aimed at controlling hypertension mainly directed towards the large cities .
most of the studies done so far in these urban areas can not therefore give a true estimate of the extent to which the rural population is affected by this major cardiovascular disease risk factor .
an analysis of hypertension and its risk factors in rural cameroon will therefore help guide health policy decisions and provide baseline data for future studies aimed at addressing this problem .
we therefore had the following as objectives : determining the prevalence of hypertension in the adult population in the moliwe health area in rural cameroon ; identifying the risk factors associated with htn in this rural setting ; determining the extent of bp control in known hypertensive patients in this locality .
a community - based cross - sectional descriptive and analytical study was conducted over a 6-month period ( june 20 to december 28 , 2013 ) in the moliwe health area ( mha ) .
this principally rural health area is found in the limbe health district of the south west region of cameroon .
a multistage sampling method was used to select participants from the 5 villages / settlements of the health area : bonadikombo , wotutu , ewongo , moliwe , and tomatal .
the sample selected was self - weighted through the probability proportional to size method used . the data of 2005 cameroon census was used as a guide to the sampling frame with households considered as the primary sampling units . using a random start
, a systematic sample of households was then selected from a list of the approximate cumulative number of households of all the villages .
this gave an estimate of the number of households to be selected from each village .
as the secondary sampling units , two participants were then recruited from each selected household by simple random sampling from a list of eligible households occupants produced by the respective household heads .
three hundred and twenty - nine participants were thus recruited from bonadikombo , 113 from wotutu , 112 from moliwe , 96 from ewongo , and 83 from tomatal .
a combined estimate of the prevalence of htn in rural rwanda , tanzania , and malawi of 22% was used .
we recruited 733 participants by systematic and simple random sampling methods . at each selected household ,
a questionnaire was administered to each recruited participant to collect information on age , sex , level of education , marital status , status of htn , treatment of htn , smoking , quantity of alcohol intake , physical activity , diabetes status , and family history of htn .
blood pressure measurements were also done at the home of the participants by a casually dressed clinician not in white coat .
two measurements ( in mmhg ) were taken on the right arm using an automated electronic bp machine ( omron m3 hem-7200-e omron matsusaka co. ltd . , kyoto , japan ) through the standard procedure ( jnc 7 recommendations ) . heights in meters ( m ) and weights in kilograms ( kg )
were measured using standard procedures and were used to determine the body mass index ( bmi ) as follows : bmi = weight ( kg)/[height ( m )  height ( m ) ] . who steps surveillance manual
the data was entered into epi info statistical software , version 7.0 ( cdc / who , atlanta , usa ) .
frequencies and means were obtained for appropriate variables ; chi - square and fischer 's exact tests were used as appropriate to test for associations between binary and categorical variables .
a logistic regression model was built to assess the effect of factors found to be significantly associated with hypertension while controlling for potential confounders .
an ethical clearance was obtained from the institutional review board of the faculty of health sciences , university of buea .
administrative approvals were obtained from the regional delegate of public health as well as from the local chiefs , quarter heads , and camp presidents concerned .
all patients found to have elevated blood pressure values were advised and referred to the nearest health facility for proper management and follow - up .
of the 733 participants , 479 ( 39.5% ) were between 20 and 29 years .
the male to female ratio was 1  :  1.2 , 35.9% had primary education , and 50.5% were married .
less than half of the participants ( 47.3% ) had normal bmi and 15% had sedentary life style . a small proportion , ( 2.9% )
were known diabetics and 32.7% reported a family history of hypertension ( table 1 ) .
of the 733 participants recruited , 228 were hypertensive , giving a prevalence of 31.1% ( 95% ci : 27.834.6 ) .
sixty - six of the 228 hypertensive participants ( 28.9% , 95% ci : 23.235.3 ) knew their status prior to our study .
of these 66 known hypertensive participants already aware of their status , 14 of them ( 21.2% , 95% ci : 12.133.3 ) had their blood pressures well controlled even though as high as 47 of them ( 71% , 95% ci : 58.781.7 ) were on antihypertensive treatment at that moment ( figure 1 ) .
age 40 and above , obesity , smoking , alcohol consumption , diabetes , low educational level , and marriage were found to be associated with hypertension ( table 2 ) . after adjusting for all significant factors using logistic regression , only age 40 and above , obesity , low educational level , and marriage
there was a progressive increase in the prevalence of htn with age when age below 40 was used as the reference : from 3 folds in the 4059 years , through 8.3 folds in the 6079 years , to 11.6 folds in 80 years age groups .
people who were obese had 2.8 times the odds of being hypertensive compared to the nonobese .
those who never went to school had 6.7 times the odds of having htn compared to those who had at least high school education ( table 3 ) . since the new recommendations for htn diagnosis and management by jnc 7 in 2003 , no study had been done in rural cameroon . the last published rural study on htn was as far back as 1998 .
the 31.1% prevalence of htn observed in the mha is similar to the 31.0% reported in cameroon by kingue et al .   and the 32.9% reported by amoah   in semiurban ghana but higher than that reported elsewhere [ 3 , 7 , 8 , 12 , 16 , 17 ] .
however , our value was lower than 44.7% reported by williams et al .   in rural ghana and 40% reported by chow et al .   in rural and urban high , middle , and low income countries .
our study revealed low hypertension awareness similar to the 32.3% observed in rural ghana by addo et al .   and the 32.6% observed by dzudie et al .   in urban cameroon .
however , this value is higher than the 11% reported in rural cameroon by mbanya et al .
this variation between rural and urban settings could be explained by poor knowledge of the disease , lesser access to health facilities , and poverty , in rural compared to urban communities .
age was identified to be strongly associated with htn , supporting the findings of other studies [ 9 , 12 , 2123 ] .
this is because as people get older , their blood vessels become harder and they are likely to have decreased baroreceptor sensitivity , increased responsiveness to sympathetic nervous system stimuli , altered renal and sodium metabolism , and an altered renin - aldosterone relationship thereby predisposing them to high blood pressure .
obesity , which is one of the common pathways between diabetes and htn , was also found to be strongly associated with htn in our study , as earlier documented [ 8 , 26 ] .
low educational status and being married were strongly linked with htn in our study as reported in previous studies [ 21 , 27 , 28 ] . a poor understanding of the disease and its risk factors and the stress experienced my married couples , respectively ,
could put these groups at a higher risk . on the other hand , gender , family history of htn , overweight , and physical inactivity
smoking , alcohol consumption , and diabetes mellitus which were associated with htn on bivariate analysis were not significantly associated with hypertension on multivariate analysis by logistic regression .
the proportion of known hypertensives who were currently on antihypertensive treatment in our study was similar to the 64.9% reported   in ghana but much higher than the 12.5% reported   in cameroon
. the high proportion on antihypertensives may be due to the increase in awareness of htn and the availability and access to antihypertensive medications in cameroon lately compared to 16 years ago . despite this considerable proportion of hypertensive patients being on treatment ,
reported as low as 3% in rural nigeria   and yuvaraj et al . reported 12.5% in rural india
however , higher proportions have been reported ( 33.1%   and 63.2% ) among hypertensives in urban and semiurban settings in cameroon , respectively , 56.8% in mexico , and 75.9% in urban india .
in this context noncompliance to treatment is multifactorial in aetiology with reasons such as inadequate knowledge of htn , intolerance of side effects of medications , and low purchasing power .
this study was cross - sectional which means participants declared hypertensive may not necessarily be hypertensive clinically .
also , our study was done in a small rural area whose findings may not necessarily apply to all rural cameroonian or sub - saharan african communities . moreover , some known risk factors such as dyslipidaemia , salt intake , and psychosocial and socioeconomic status were not assessed in our study .
nevertheless , the large sample size , varied sampling method , and execution of standard measurement procedures make the findings of this study robust and accurate .
also , the white coat effect which could potentially produce an overestimation of the actual prevalence of hypertension in this setting was minimized since the casually dressed clinician without a white coat did the measurements from the participants ' homes .
our study revealed that about one out of three adults in the moliwe health area could be hypertensive with only a quarter of them being aware of their status and a fifth of those on treatment having their blood pressure well controlled .
this reveals how very much a cardiovascular risk the rural population may be exposed to .
there is , therefore , need for massive improvement in awareness through education and repeated patient follow - up in these rural settings alongside the urban ones .
also , the importance of further research in other rural communities to assess trends and risk factors of hypertension and the extent of blood pressure control can not be overemphasized .

Answer:
background . despite the increasing trends suggesting that hypertension is a growing public health problem in developing countries , studies on its prevalence , associated risk factors , and extent of blood pressure control have been inequitably done in urban and rural communities in these countries .
 we therefore aimed to determine the prevalence of hypertension and extent of blood pressure control in rural cameroon .
 methods .
 this was a community - based cross - sectional study conducted in rural cameroon ( the moliwe health area ) .
 participants aged 21 years and above were recruited by a probability proportional to size multistage sampling method , using systematic sampling for household selection and random sampling for participant selection .
 blood pressure , weight , and height were measured by standard methods .
 hypertension was defined as bp  140/90  mmhg .
 results .
 the prevalence of hypertension among the 733 participants recruited was 31.1% ( 95% ci : 27.834.6 ) and 71% ( 95% ci : 58.781.7 ) of these hypertensive patients were newly diagnosed . only 21.2% ( 95% ci : 12.133.3 ) of known hypertensives had a well controlled bp .
 age , obesity , low educational status , and being married were associated with htn after adjusting for confounders .
 conclusions . the high prevalence of hypertension and inadequate bp control among known hypertensives in rural cameroon warrants greater sensitization and regular screening to reduce hypertension - related morbidity and mortality .


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:
congenital seminal vesicle cysts associated with abnormalities of the upper urinary tract are uncommon.1 they can be asymptomatic and discovered incidentally or can be associated with dysuria , urinary tract infections , and infertility .
diagnosis is more frequently made in adult life during the period of the greatest sexual or reproductive activity.1
 2 we present a case of a congenital seminal vesicle cyst associated with ipsilateral renal agenesis incidentally discovered on ultrasound at the age of 4 years and its natural evolution until adolescence .
the association of congenital seminal vesicle cyst with ipsilateral renal malformations is rare and was first described by zinner in 1914 .
it is reported in literature as  zinner syndrome.3 this condition is considered as the male equivalent of mayer - rokitansky - kustner - hauser ( mrkh ) syndrome described in females.4

a 4-year - old boy with known right renal agenesis discovered on antenatal ultrasound , presented in our radiology department for his annual control .
the cyst was anechoic , measured 8  mm , and was not present on previous ultrasounds .
it was initially considered as an ureterocele or bladder diverticula , however , neither of these diagnosis was confirmed on intravenous urography performed at that time .
the cyst remained unchanged on size and aspect during 11 years of follow - up .
however , at the age of 15 years its aspect on the ultrasound had changed : its content was hyperechoic , it had increased in size ( measuring 1.9 cm ) , and protruded in the bladder .
it was associated to magma of some echogenic , round retrovesical masses , initially considered as lymph nodes ( fig .
1b , c ) . magnetic resonance imaging ( mri ) of the urinary tract and pelvis was further performed ( coronal , axial , and sagittal t2 spin - echo and axial t1 with fat saturation before and after gadolinium injection images ) .
it revealed a dilatation of the seminal vesicles , ipsilateral to renal agenesis ( corresponding to the magma of retrovesical round masses seen on ultrasound ) , ending to a relatively small seminal vesicle cyst ( diameter of 2 cm ) that protruded in the bladder ( fig .
2 a  c ) .
 ultrasound ( a ) at the age of 4 years detects a right retrovesical anechoic cyst ( + ) ( b ) at the age of 15 years the cyst has increased in size and it has become hyperechoic ( white arrow ) .
( c ) it is associated to magma of round retrovesical masses ( black arrow ) .

( b ) t2 spin - echo axial and ( c ) sagittal images of the pelvis show dilatation of the right seminal vesicles ( white arrow ) ending to a seminal vesicle cyst ( * ) that protrudes in the bladder .
so far , the patient was asymptomatic and had never presented with dysuria , signs of bladder obstruction or urinary tract infection .
he had neither any perineal discomfort nor pain , he described normal ejaculation without pain , no hematospermia , and had never experimented any urinary infection or prostatitis and also he was not sexually active . in this particular case , in the absence of symptoms and because of the relatively small size of the cyst a conservative treatment was decided , with an annual clinical and ultrasonographic control , at least until the first symptoms appear .
the association of congenital seminal vesicle cyst with ipsilateral renal malformations is rare and there are approximately 200 cases reported in the literature.4
  this association is explained by the common embryologic origin of both the organs ( kidneys  seminal vesicles ) from the mesonephric duct1 and is due to an insult in embryogenesis between the 4th and 13th week of gestation.4 the ureteral bud arises from the dorsal part of the distal mesonephric duct and extends dorsocranially to meet and induce differentiation of the metanephric blastema , from which the kidney will develop .
the mesonephric duct will differentiate to epididymis , ejaculatory duct , vas deferens , seminal vesicle , and hemitrigone .
complete failure of the mesonephric duct results to absence of ipsilateral kidney , ureter , hemitrigone , and seminal vesicle .
anomalous development of the distal mesonephric duct results to atresia of the ejaculatory ducts and abnormal ureteral budding ; the former leads to obstruction and cystic dilatation of the seminal vesicles with development of seminal cysts , the latter leads to renal agenesis or dysplasia.2
 5 zinner syndrome could be considered as the male equivalent of mrkh syndrome described in females.4
  the cysts are present since birth but enlarge and become symptomatic on late adolescence or adult life , usually in the third to fifth decade , at the period of greatest reproductive or sexual activity.1
 2 at this moment the accumulation of secretions in the seminal vesicle due to atresia of the ejaculatory ducts and consequently insufficient drainage leads to formation of cysts in the seminal vesicle.2
  cysts smaller than 5 cm are usually asymptomatic and are discovered incidentally .
larger cysts can irritate the bladder and be related to pain , dysuria , frequency , hematuria , urinary tract infection , epididymitis or prostatitis , infertility , hemospermia , bladder outlet , or colonic obstruction.1
 2
 6 malignant degeneration of the cysts has been also reported.2
 4
  this progressive dilatation of seminal vesicle remains often asymptomatic until the dilatation increases to 4 to 5 cm,4
 5 unless the obstruction triggers vas deferens dilatation at younger age,5 which was not the case for our adolescent .
this dilatation develops slowly , by accumulation of secretions in the seminal vesicle , for many years after puberty , due to congenital atresia of the ejaculatory ducts and consequently insufficient drainage2 : literature reports a majority of cases becoming symptomatic around the third or fourth decade of life .
diagnosis can also be made earlier in front of infertility linked to contralateral distal ejaculatory pathway compression by this cystic seminal vesicle.3
  in our case , the cyst was first seen at the age of 4 years , mimicking an ureterocele on ultrasound . in adolescence
it increased in size , but remained small and , for this reason , asymptomatic .
diagnosis was made on mri , based on its anatomic connection and to the similar signal intensity with the seminal vesicles .
differential diagnosis includes other pelvic cystic masses such as utricular or mullerian cyst , ureterocele , dilated ureter , abscess or lymph nodes,2
 4 and acquired seminal vesicle cysts .
acquired cysts are usually bilateral and concern older patients with chronic prostatitis or postprostate surgery .
ultrasound raises the suspicion of this malformation but the final diagnosis is usually made by mri ( or computed tomography , with this last method being irradiating ) . in adults
more invasive methods as cystoscopy and vasovesiculography are also used for diagnosis.2
  there is a medical consensus to propose conservative follow - up for asymptomatic or minimally symptomatic cysts.1
 4
 7 treatment is considered only for symptomatic patients and is surgical .
different surgical options exist , from the less invasive transrectal or transperineal aspiration of the cyst which gives a transitory relief of the symptoms,1 to more aggressive technics .
transurethral unroofing of the cyst by transurethral resection of the ejaculatory duct provides improvement of the quality of semen and improves the paternity rate,3 but this procedure can create injury to rectum , bladder neck , and external sphincter , and induce consequent retrograde ejaculation , and epididymitis . radical treatment , vesiculectomy with resection of ureteral or renal remnants if present , offers the better outcome .
it was traditionally performed by open exploration but is now well described laparoscopically , with low morbidity and good results in term of symptoms
relief and semen parameters.1
 4
 7
 8
 9
 10
 11 few children with surgical indication benefited from this approach.12
 13
  concerning fertility , for patients presenting with difficulty to procreate , with low volume of semen and poor quality of spermogram , treatment shows semen quality improvement , and paternity obtained without other medical help.3
 4 assisted reproductive procedures should be kept for patients with infertility persisting after successful surgical procedure.4
  our case is original as it shows the natural history and evolution of this malformation , from childhood to adolescence .
cases reported in literature concern , in their high majority the adult population ( or late adolescence ) and these cysts are rarely detected at a younger age .
congenital seminal vesicle cysts in patients with ipsilateral renal agenesis are rare but this association is known and should be considered in the differential diagnosis of cystic pelvic masses in males with renal agenesis or dysplasia .
ultrasound is useful for diagnosis but mri provides a more detailed analysis and accurate diagnosis .
congenital seminal vesicle cysts in patients with ipsilateral renal agenesis are rare but this association is well known .
pediatric surgeons should be aware and consider this entity in the differential diagnosis of cystic pelvic masses in males with renal agenesis or dysplasia .
ultrasound is useful for diagnosis but magnetic resonance imaging provides a more detailed analysis and accurate diagnosis .

Answer:
zinner syndrome , the association of congenital seminal vesicle cyst and ipsilateral renal agenesis , is more often reported in adults or older adolescents .
 we present a case of a boy , followed up in our hospital since birth for right renal agenesis who at the age of 4 years presented a right paravesical cyst on ultrasound .
 the cyst was initially considered as an ureterocele .
 the diagnosis of zinner syndrome was made later , at the age of 15 years by ultrasound and magnetic resonance imaging ; at that moment the cyst had increased in size and had changed in aspect .
 this malformation should be considered in the differential diagnosis of a pelvic cyst in male patients with renal agenesis .


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:
a woman in her 30s with acquired immunodeficiency syndrome ( aids ) diagnosed by the fourth - generation hiv testing , with a cd4 count of 3 ( 1% ) cells / mm , presented with weight loss and cachexia . she was started on lamivudine , zidovudine , and nevirapine and then developed hypersensitivity rash and hepatitis . at that time , she also had pancytopenia ( white blood cells 2,950/l , neutrophils 79% , lymphocytes 13% , hemoglobin 9.6 g / dl , hematocrit 29% , platelets 325,000  10/l ) and intra - abdominal lymphadenopathy .
she was treated initially for presumptive disseminated mycobacterial infection with isoniazid , rifampicin , pyrazinamide , ethambutol , and clarithromycin .
she improved clinically , and her antiretroviral regimen was restarted after three weeks with lamivudine , tenofovir , and efavirenz .
later on , she had gained weight , and laboratory results showed the resolution of pancytopenia and hepatitis .
two months later , the antibiotic regimen was readjusted to ciprofloxacin , clarithromycin , and streptomycin injection ( for one month ) according to the susceptibility , and her clinical improvement was remarkable .
two months after the initiation of antiretroviral therapy ( art ) , she had an hiv viral load of < 40 copies / ml and a cd4 count of 1 ( 2% ) cell / mm ; however , she had recurrent transaminitis .
she was given prednisolone 20 mg / day with a tapered dose for five weeks for the treatment of hepatitis possibly due to immune reconstitution inflammatory syndrome .
five months after the initiation of art , her cd4 count was 13 ( 3% ) cells / mm , with an hiv viral load of < 40 copies / ml .
she developed cytomegalovirus retinitis and received intravitreal ganciclovir injection and oral valganciclovir for six weeks .
she then developed abdominal pain , with a palpable large suprapubic mass , for three weeks .
a computed tomography ( ct ) scan of the abdomen showed a large lobulated mass ( 8.5  10 cm ) with the epicenter at the right adnexa and with the invasion of the uterus , right ovary , right lateral wall of the sigmoid colon , appendix , superior wall of the urinary bladder , and right distal ureter , causing right ureter obstruction and a moderate degree of right hydronephrosis .
multiple matted lymph nodes were present along the mesenteric root and in the para - aortic , aortocaval , and retrocaval regions .
focal circumferential wall thickening of the left side of the jejunum caused moderate intraluminal narrowing , with evidence of small bowel obstruction ( fig .
she underwent exploratory laparotomy ; intraoperative findings revealed a large pelvic mass with nodular surface and with dense adhesion to the omentum , the anterolateral wall of the uterus , the bladder , and the sigmoid colon
. only partial resection of the omentum and a biopsy of the mass at the anterior aspect of the uterus were performed .
acid - fast and gomori methenamine stains of the tissue specimen were negative ; however , microbial culture was not sent for laboratory analysis .
her hospital course was complicated by wound infection / dehiscence , with the formation of an enterocutaneous fistula .
she suffered from abdominal pain as well as malnutrition due to the nature of the unresectable residual mass and the enterocutaneous fistula .
she was discharged home on palliative care , with antimicrobial therapy , and was lost to follow - up . disseminated m. simiae infection presented with pancytopenia , hepatitis , and lymphadenopathy , similar to mycobacterium avium infection in an aids patient.1 effective antimicrobial treatment of m. simiae included rifampicin and ciprofloxacin .
our patient had an abnormal host immune response to infection , malakoplakia , which occurred after m. simiae infection , a condition that has not been previously described in the literature .
however , we were unable to demonstrate a direct correlation due to the lack of microbiological data from tissue specimens .
malakoplakia has a gross appearance of round , oval , or mushroom - shaped yellowish structures.2 histologically , there is a proliferation of histiocytes with abundant granular eosinophilic cytoplasm ( known as von hansemann histiocytes ) that contain the pathognomonic michaelis
gutmann bodies.2 these bodies are round to oval in shape and are visible as deeply basophilic structures , which are typically described as target - like and are periodic acid
schiff stain - positive and calcium - positive.2 pathogenesis of malakoplakia is associated with the lysosomal dysfunction of macrophages in the intracellular killing process of ingested organisms and/or a defect in elimination , resulting in the accumulation of partially degraded bacteria within the cytoplasm and phagolysosomes of histiocytes , forming michaelis
gutmann bodies around the undigested bacteria.2 the most common infectious etiologies described are bacteria , such as escherichia coli , rhodococcus equi , pasteurella multocida , and mycobacterium tuberculosis.211 malakoplakia often occurs in immunocompromised patients , such as those with aids , organ transplant recipients ( mostly solid organ transplants ) , and in one case a patient who had undergone stem cell transplantation.5,1114 malakoplakia affecting a major organ could result in various organ dysfunctions .
one of the most serious adverse events reported was irreversible renal allograft dysfunction due to malakoplakia in a renal transplant recipient with e. coli infection , pyelonephritis , and bacteremia.14 in an allogeneic stem cell transplant recipient , pleural malakoplakia caused by r. equi , presenting with a large tumor mass , required a lobectomy.12 in patients with residual disease , successful results have been reported by treating the underlying infection , reducing immunosuppression , improving the bactericidal activity of monocytes with a cholinergic agonist , such as bethanechol , and administering a multivitamin supplement.4,15,16 this is the first report of malakoplakia occurring after m. simiae infection .

Answer:
malakoplakia in an acquired immunodeficiency syndrome ( aids ) patient with disseminated mycobacterium simiae infection presented with a large pelvic mass that caused organ dysfunction from mimicking a tumor .
 malakoplakia is a rare , chronic granulomatous abnormal host response toward infectious agents , presenting as a tumor - like lesion .
 this is the first report of pelvic malakoplakia after disseminated m. simiae infection in an aids 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:
the missouri department of health and senior services conducted this investigation in response to the hospital s identification of an increased number of tracheal aspirates that were positive for b. cereus collected from newborns who were on ventilators during march  may , 2011 .
all tracheal aspirate culture results obtained in the neonatal intensive care unit ( nicu ) during january 2010june 2011 were reviewed .
nicu data was also searched for positive b. cereus culture from other specimens , such as blood , body fluids , or tissues .
investigators thoroughly evaluated respiratory management practices in the unit by direct observation , respiratory records review , and an interview with the respiratory therapist .
several environmental cultures were obtained from the flow sensors of the unit s ventilators over the 1-month period .
b. cereus isolates were forwarded to the centers for disease control and prevention to be molecularly characterized by using multilocus sequence typing ( mlst ) ( 10 ) .
the dna was used as a template in pcrs with the primers described on the bacillus cereus mlst web site ( www.pubmlst.org/bcereus ) for the 7 loci which define the mlst scheme .
the sequences for the loci glpf , gmk , ilvd , pta , pur , pyca , and tpi were then assigned allele designations .
a greater number of alleles that match between strains indicates a higher level of relatedness ( 10 ) .
prevalence of b. cereus  positive specimens was compared by using the mann - whitney u test .
retrospective analysis of tracheal aspirate culture results showed significant increase ( p = 0.039 ) in b. cereus isolation between march and may , 2011 ( figure 1 ) .
no bacillus spp . were isolated from blood , other body fluids , or tissues during the study period .
the chart review of the case - patients comprising the cluster of b. cereus colonization revealed that none received a diagnosis of clinical b. cereus infection .
all patients were treated with vancomycin or tobramycin , or both , for indications not related to b. cereus in tracheal aspirate .
one case - patient died 108 days later without evidence that b. cereus contributed to the outcome .
epidemiologic curve of bacillus spp.positive tracheal aspirates from newborns on ventilators , january 2010january 2012 .
investigation of the ventilation procedures in the nicu revealed that most equipment used for respiratory care was disposable , designated for single - patient use .
telford , pa , usa ; www.draeger.us/sites/enus_us/pages/hospital/evita-xl.aspx ) was used for mechanical ventilation of infants who were intubated to treat severe respiratory compromise .
the draeger evita v500 is a microprocessor controlled ventilator offering both mandatory and spontaneous ventilation modes for adult , pediatric , and neonatal patients .
heated and humidified gas flows from the ventilator unit , through the inspiratory circuit and neoflow air flow sensor to the patient through an endotracheal tube . upon exhalation , gas flows back through the air flow sensor into the expiratory circuit and returns to the ventilator through the expiratory flow sensor and exhalation valve .
in addition to the ventilator , reusable respiratory equipment comprised a proximal air flow sensor , expiratory flow sensor , exhalation valve , and circuit temperature probe .
the sensor closest to the newborn s mouth was an air flow sensor located inside the disposable ventilation circuit ( figure 2 ) .
from 9 environmental cultures obtained from 9 air flow sensors , 1 was positive for bacillus spp . , and was later confirmed as b. cereus by the state public health laboratory .
mlst was performed for 8 b. cereus isolates from case - patients and for 1 environmental isolate from the air flow sensor .
one locus for the remaining 5 strains did not yield an amplicon for sequencing after repeated attempts and , thus , could not be assigned a sequence type .
the isolates that included sequence type ( st ) 73 and st94 were closely related to each other because they differed by merely 1 locus , gmk .
the strains that were not fully typed because of the inability to obtain sequences for locus pta were also closely related to st73 or st94 because the other loci matched .
there was 1 match between strains isolated from 1 case - patient and the air flow sensor , which was st73 .
the contaminated air flow sensor was then sterilized by using a steam autoclave . a repeat culture of this sensor after sterilization was negative .
we found that air flow sensors were routinely disinfected by placing them in a container with 70% alcohol solution for 60 minutes .
after discovery of the air flow sensor contaminated with b. cereus , the disinfection policy was changed .
all air flow sensors were first soaked in enzol enzymatic detergent ( asp , irvine , ca , usa ; www.aspjj.com/us/products/enzol ) solution and then sent for steam autoclave sterilization at 134c ( 273.2f ) .
after implementation of new disinfection and sterilization procedures , no new cases of b. cereus tracheal colonization were identified in the nursery . in this cluster ,
contaminated proximal air flow sensors were the likely source of tracheal colonization with b. cereus in newborn infants , supported by a genetic match by mlst between a strain isolated from 1 case - patient and the contaminated air flow sensor .
b. cereus transmission from contaminated respiratory equipment has been reported in other geographic areas . in the netherlands , an outbreak of b. cereus infections in a pediatric intensive care unit caused by contaminated reusable ventilator air flow sensors
switching to disposable air flow sensors stopped colonization with b. cereus in that unit . in canada , an outbreak of b. cereus infections among patients in an adult icu was linked to colonized ventilator circuitry ( 8) . in the united kingdom , reusable ventilator circuits were also identified as the cause of a b. cereus outbreak among intubated nicu patients ( 9 ) .
our investigation underscores the necessity of close monitoring of occurrences of bacillus spp . in tracheal aspirates since clustering of such cases
, b. cereus isolates were either st73 , st94 , or closely related to those sequence types .
st73 and st94 are associated with strains previously described as having caused illness in elderly persons .
strains with st73 were implicated in cases of septicemia ( 12 ) , and of sepsis and pneumonia ( 13 ) . strains with st 94 were recovered from patients with pneumonia ( 14 ) .
b. cereus strains harboring b. anthracis plasmids such as pxo1 , have also been associated with severe and fatal respiratory infections ( 15 ) .
all case - patients in our investigation were considered to be colonized with b. cereus without clinical implications .
since all of them received intravenous antimicrobial drugs effective against b. cereus , it is conceivable that the clinical course of those patients could have been different without such treatment .
should not be routinely viewed as clinically insignificant and further testing to determine exact strain should be considered under appropriate clinical and epidemiologic circumstances .
proper disinfection of the entire ventilator circuit as recommended by the equipment manufacturer is crucial in avoiding potentially lethal b. cereus infections .

Answer:
we investigated bacillus cereus  positive tracheal aspirates from infants on ventilators in a neonatal intensive care unit .
 multilocus sequence typing determined a genetic match between strains isolated from samples from a case - patient and from the air flow sensor in the ventilator . changing the sterilization method for sensors to steam autoclaving stopped transmission .