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Biomedical subjects

S Roy

Publications and source records attributed to S Roy.

At least 1,045 records · Page 58Linked to original sources
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Multiple emboli and filter function: an in vitro comparison of three vena cava filters.

PURPOSE: To establish the influence of number of emboli on the trapping ability of vena cava filters in vitro. MATERIALS AND METHODS: Three filters, the titanium Greenfield, Vena Tech-LGM, and Günther Tulip retrievable, were studied with use of 20- or 26-mm-diameter tubes to simulate the inferior vena cava. In the first protocol, five small (4 x 20-mm) or medium (6 x 10-mm) emboli were delivered in sequence, and the fate of each was recorded. In the second protocol, medium or large (6 x 30-mm) clots were sequentially introduced until filter occlusion occurred or 50 clots had been delivered. RESULTS: For the first protocol, 82% of first small clots and 60% of second clots were trapped in 20-mm tubes (P = .001) and 63% and 45%, respectively, were trapped in 26-mm tubes (P - .02). With medium clots, the proportion trapped also dropped significantly with ascending clot rank. In the second protocol the proportion of clots captured was invariably higher for the first 10 clots (P < .001 for all combinations of covariables). CONCLUSION: Filter function deteriorates with number of emboli delivered, irrespective of embolus size and simulated vein caliber.

Confidence Intervals↗
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Treatment of recurrent posterior and bulbar urethral strictures with expandable metallic stents.

PURPOSE: The role of expandable metallic Z stents (non-mesh) in the treatment of recurrent posterior and bulbar urethral strictures was evaluated. PATIENTS AND METHODS: Seven men with recurrent posterior/bulbar urethral strictures underwent balloon angioplasty followed by insertion of two stents in tandem. Retrograde urethrography, micturating cystourethrography, and urodynamic evaluation of these patients was done initially. RESULTS: Successful dilation and placement of stents was possible in all cases. In one patient slight proximal migration of the stent occurred; terminal dysuria in this patient necessitated stent extraction. In two other patients near total occlusion of the stent by an exuberant fibrous reaction occurred and this open urethroplasty in the other. Immediate postprocedure urethrography and urodynamic evaluation showed significant improvement. Five patients continue to show a satisfactory clinical urodynamic response. The follow-up period in this patient group ranged from 5 months to 1 year. CONCLUSION: Short-term response (5 months to 1 year) in patients with posterior/bulbar urethral strictures treated with Z stents appears promising. However, the efficacy of the procedure on a long-term basis requires further follow-up and evaluation.

Adult↗
PubMedDate not supplied

Management of idiopathic Budd-Chiari syndrome with primary stent placement: early results.

PURPOSE: To evaluate the utility of primary stent placement in the management of Budd-Chiari syndrome (BCS) secondary to idiopathic inferior vena caval (IVC) obstruction. PATIENTS AND METHODS: The case records of nine patients (four women, five men), ranging in age from 22 to 58 years (median, 26 years), with idiopathic IVC obstruction were reviewed. Hepatosplenomegaly, esophageal varices, and prominent collateral veins were found in all patients, while four also had ascites. Hepatic functional reserve was graded as Child class A in three patients and class B in the remaining six. All had at least one patent hepatic vein opening into the IVC below the site of occlusion. Percutaneous angioplasty of the IVC was performed, followed by the placement of double-skirt Gianturco-Rösch or hybrid Gianturco stents. Clinical follow-up was supplemented with duplex ultrasound (n = 8), endoscopy (n = 4), and cavography (n = 2). RESULTS: Caval lesions were segmental. Revascularization was technically successful in all patients. The median pressure gradient across the lesion dropped from 38 mm Hg (range, 27-61 mm Hg) to 15 mm Hg (range, 10-20 mm Hg) (P = .008). Residual stenosis after stent placement ranged from 9% to 40% (median, 20%). One patient died of presumed pulmonary embolism; another patient experienced an episode of epistaxis. The procedure was followed by regression of signs and symptoms in the eight survivors. During the follow-up period (range, 3-31 months; median, 7 months) the IVC remained patent in all patients, and clinical features of BCS did not recur. CONCLUSION: Primary stent placement could serve as the first line of treatment in patients with idiopathic BCS when the underlying lesion is not amenable to angioplasty.

Adult↗
PubMedDate not supplied

Induced thrombosis in the pig inferior vena cava: a model of deep venous thrombosis.

PURPOSE: To establish a new animal model of deep venous thrombosis. MATERIALS AND METHODS: Fifteen young pigs underwent temporary interruption of the inferior vena cava (IVC) below the entry of the right renal vein by means of either a silicone band (surgical technique, n = 6) or an intraluminal balloon catheter (endovascular technique, n = 9), followed by injection of absolute ethanol. Lumbar veins within 3 cm below the obstruction were ligated or occluded interventionally. The iatrogenic caval obstruction was relieved after 2 days. RESULTS: Procedure-related mortality was 33% (n = 2) and 11% (n = 1) for the surgical and endovascular groups, respectively. An adherent, occlusive thrombus was found in all four of the remaining surgically treated animals and in six of eight animals treated percutaneously. The IVC remained patent in two animals in whom balloon migration occurred. Severe caval stenosis invariably occurred after surgical banding. CONCLUSION: IVC thrombi suitable for the study of various recanalization therapies can be reliably created with this pig model.

Angioplasty, Balloon↗
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Topological shape and size of peptides: identification of potential allele specific helper T cell antigenic sites.

A database of primary sequences of 28 immunogenic peptides, known to elicit T cell response, derived from five different haplotypes was compiled to identify allele specific helper T cell antigenic sites using a rule based graph-theoretical method. The prediction was based on the identification of allele specific patterns in the form of "topological shape and size" present in the peptides. Indices computed from weighted connected graph models of amino acid side chains and peptides were used in this purpose. The system was trained by 10 Ad and 10 non-Ad restricted peptide sequences, assigned actives and inactives, respectively, chosen randomly from the database, and four Ad and four non-Ad restricted sequences were kept as test peptides. This allowed the system to learn about "topological shape and size" specific for Ad restricted peptides from the differences, if any, they had with the inactive peptides in that respect. The system made 100% correct prediction for the training set peptides and misclassified only one inactive peptide of the test set. The system also identified crucial residues for lambda repressor 12-24 and insulin A-chains. This identification also shows that activity related/crucial residues could be located at varying distances from the peptide terminals. To our knowledge, the method is unique of its kind in the literature and may find application in the rational design of synthetic vaccines and other peptides of immunological importance.

Alleles↗
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Profiling of human leukocyte antigens in Eales' disease.

Eales' disease is a primary retinal perivasculitis of an undetermined etiology seen predominantly in the Indian subcontinent and rarely in the West. Strong HLA association has been proven in retinal vasculitis of Behcet's disease. HLA association of Eales' disease is unknown and therefore the present study was undertaken to determine the same. The frequency of 30 HLA antigens (9 HLA-A antigens, 10 HLA-B antigens, 3 HLA-C antigens, 7 HLA-DR antigens and 1 HLA-DQ antigen) was studied by standard micro-lymphocytotoxicity test in 57 patients with Eales' disease and 50 age and sex-matched normal persons as controls. Both the patients and controls underwent complete ocular and clinical examinations and laboratory investigations. Inflammatory diseases similar to Eales' disease were ruled out in the patients before they were enrolled. Statistically significant higher phenotype frequencies of HLA B5 (B51), DR1 and DR4 were observed among patients with Eales' disease as compared to controls. The gene frequency of HLA B5 (B51) in our group of patients and controls was comparable with other earlier studies in the Indian population. The finding of significant association of Eales' patients with positive disequilibrium ( ) haplotypes A3-B44 and A11-B12 may be related to the development of this disease. The presence of the above HLA antigens may be indicative of predisposition to Eales' disease.

Adolescent↗
PubMedDate not supplied

Are Muslim women less susceptible to oncogenic human papillomavirus infection? A study from rural eastern India.

Muslim women are known to have lower incidences of cervical cancer and/or human papillomavirus (HPV) infection. Here we aim to determine any association that may be present between the oncogenic HPV16/18 infections and abnormal cytological lesions along with demographic and other attributes among Indian Muslim women (n = 478) and compare with the neighboring Hindus (n = 534) from a prospective cohort study. Agewise distribution of both subject-groups is similar. HPV16/18 infection is present in 9.6% Muslims and 7.5% Hindu women. Jointly atypical cells of undetermined significance (a typical cells of undetermined significance) and HPV16/18 are present in seven Muslim and two Hindu women. No high squamous intraepithelial lesions or cervical cancer is detected at the baseline. HPV16/18 infections show trends that varied with age, a nonlinear trend among Muslim women. In Hindu women the prevalence is highest at age < or =24 years, which linearly drops with increasing age. Abnormal cytology increases significantly in both religion-groups with increasing age. The data show that these Indian Muslim women are equally susceptible to HPV16/18 infection and for the development of abnormal cytology. There is a paucity in epidemiological data, which justifies the need to screen women of all religions for cervical cancer (that includes oncogenic HPV testing).

Adult↗
PubMedDate not supplied

Uterine effects of tamoxifen: a prospective study.

The purpose of the study was to evaluate tamoxifen-associated changes in the vagina and uterus in postmenopausal breast cancer patients. Between June 1994 and December 1998, 45 patients enrolled in a prospective study before commencing tamoxifen therapy. Patients with endometrial thickness >5 mm or neoplasia were excluded. Transvaginal ultrasonography, vaginal maturation indexes (VMI), and endometrial biopsy were performed at baseline and repeated at 6 months (n= 42), 1 year (n= 39), 2 years (n= 32), 3 years (n= 26), 4 years (n= 19), and 5 years (n= 15). For the 39 patients followed for 1 year, VMI (% parabasal/intermediate/superficial) was 21/71/8 at baseline compared with 1/90/9 at 1 year (P value = 0.0008/0.001/0.78). At baseline, mean endometrial thickness and uterine volume were 2.6 mm and 64 cm(3), respectively, compared with 5.8 mm and 84 cm(3) at 1 year (P= 0.0002, 0.002). At baseline, 80% of patients had atrophic endometrium and 9% proliferative endometrium compared with 61% and 26% at 1 year, respectively (P= 0.04). No cases of endometrial hyperplasia or adenocarcinoma were detected. Findings observed at 6 months persisted through 5 years of follow-up. Tamoxifen exerts a weak estrogenic effect on the vagina and uterus in highly prescreened postmenopausal women without preexisting endometrial pathology.

Adult↗
PubMedDate not supplied

Pain during mammography: impact of breast pathologies and demographic factors.

OBJECTIVES: The aim of this study was to systematically assess the pain experienced by patients undergoing mammography for various clinical presentations. SUBJECTS AND METHODS: Two hundred and twenty-five patients aged 25-85 years (45.43 +/- 8.25 years) presenting for mammography were included in the study. Presenting symptoms and clinical diagnosis were provided by the referring physicians and demographic information was obtained from self-reported questionnaires. Mammography results were recorded by the radiologist. Two different but reliable and valid measures of pain--Visual Analog Scale (VAS) and Pain/Discomfort Rating Scale (DRS)--were used to assess pain during mammography and data were statistically analyzed to examine the possible predictors of pain. RESULTS: Forty-nine percent of the patients reported pain during mammography when cut-off level of VAS score was 40; however, when the cut-off level was raised to 60 (considering the preexisting pain as presenting symptom in some patients) only 23% reported pain. With DRS, 7% reported pain, 27% discomfort and 66% neither pain nor discomfort. Biserial correlation between the VAS and DRS scores suggested strong positive agreement between the two measures of pain (r = 0.56, d.f. = 90, p < 0.01). Patients presenting with coexisting breast lumps and preexisting breast pain and those diagnosed with inflammatory conditions of the breast and fibrocystic changes experienced more pain during mammography. CONCLUSION: Preexisting breast pathologies and demographic factors such as age and educational level of the patient were important in reporting pain during mammography. This finding indicates that proper assessment of pain using standard measures and its association with breast pathologies and demographic factors is important for planning pain management in women undergoing mammography.

Adult↗
PubMedDate not supplied

Abundance of siderophages in sputum: indicator of an adverse lung reaction to air pollution.

OBJECTIVE: To investigate the lung response to traffic-related air pollution by enumerating hemosiderin-laden alveolar macrophages (AM) in sputum. STUDY DESIGN: Sputum samples were collected from 103 urban adult males from Calcutta chronically exposed to automobile exhaust. Forty-nine rural individuals served as controls. AM were identified by nonspecific esterase staining. Perl's Prussian blue technique was employed for the detection of hemosiderin-laden AM (siderophages). RESULTS: The urban group, consisting of 31 traffic officers, 25 automobile service station workers and 47 street hawkers, had seven times more AM in their sputum than did the matched controls. Besides, a remarkable rise (27-fold) in the number of siderophages in sputum was observed in urban individuals. Smoking further elevated the AM count and number of siderophages. CONCLUSION: Abundant siderophages in the urban group may indicate the toxic effect of airborne pollutants on the lung, leading to phagocytosis of destroyed cells, including erythrocytes, and accumulation of iron in AM. Enumeration of siderophages in sputum appears to be a simple, noninvasive, inexpensive cytochemical technique well suited to preliminary assessment of the adverse effects of air pollution on the lungs in large, population-based studies, especially in developing countries.

Adult↗
PubMedDate not supplied

Biochemical responses in aquatic plants as markers of environmental contamination.

This short review gives several examples of the current status of xenobiotic biotransformation reactions and oxidative stress responses in plants as biomarkers of organic pollution in aquatic environments. Based on previous basic knowledge, several biomonitoring programmes have been applied successfully during the last decade.

Biotransformation↗
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Stress changes of the distal radial epiphysis in young gymnasts. A report of twenty-one cases and a review of the literature.

Between 1980 and 1983, 21 young, high-performance gymnasts with stress changes related to the distal radial epiphysis, were treated and followed for a mean of 24 months (range, 6 to 42 months). Eleven of the gymnasts presented with roentgenographic changes of the distal radial epiphysis, and in these recovery took at least 3 months. This group was compared to a group of ten gymnasts who had similar symptoms but no roentgenographic changes, and who recovered within an average of 4 weeks. The roentgenographic changes, which are described in detail, are considered to represent stress changes, possibly stress fractures, of the distal radial epiphysis. No residual growth-related problems have been observed. Possible etiologic factors are discussed, and the literature as it pertains to stress-related adaptation and injury in the growing athlete is reviewed.

Adolescent↗
PubMedDate not supplied

Stress changes of the distal radial growth plate. A radiographic survey and review of the literature.

We conducted a radiographic survey to determine skeletal age and the nature and prevalence of stress-related changes affecting the distal radial growth plate in 60 young competitive gymnasts (39 females, 21 males). Comparison of results for chronological and skeletal age revealed a significant delay in maturation for girls (P less than 0.001). Radiographic evaluation revealed 5 gymnasts (4 girls and 1 boy) with stress-related changes of the left wrist, and four of these were considered to be minimal. These results, in conjunction with our previous findings and the review of related literature, reveal three important observations. First, the widening and irregularities of the distal radial physis that we described previously appear to be the first in a spectrum of abnormal changes secondary to overuse and probably represent a stress fracture of the distal radial growth plate. The radiographic changes associated with this injury are not the normal adaptive changes seen in young, competitive gymnasts. Secondly, more serious long-term abnormality may result even though the injury may initially resemble a Salter-Harris type I or II stress fracture. Long-term complications may include symmetrical or asymmetrical retardation or halted growth at the affected site, positive ulnar variance, and associated pathoanatomic sequelae. Thirdly, the incidence of distal radial growth plate stress injury remains unclear; we recommend a further, large-scale prospective epidemiologic study involving both male and female gymnasts. We urge that physicians and other health professionals associated with gymnastics clubs educate coaches about the possibility of significant injury to the distal radial physis, risk factors, and suggested preventive measures.

Adolescent↗
PubMedDate not supplied

Simulation of ozone depletion using ambient irradiance supplemented with UV lamps.

In studies of the biological effects of UV radiation, ozone depletion can be mimicked by performing the study under ambient conditions and adding radiation with UV-B lamps. We evaluated this methodology at three different locations along a latitudinal gradient: Rimouski (Canada), Ubatuba (Brazil) and Ushuaia (Argentina). Experiments of the effect of potential ozone depletion on marine ecosystems were carried out in large outdoor enclosures (mesocosms). In all locations we simulated irradiances corresponding to 60% ozone depletion, which may produce a 130-1900% increase in 305 nm irradiance at noon, depending on site and season. Supplementation with a fixed percentage of ambient irradiance provides a better simulation of irradiance increase due to ozone depletion than supplementation with a fixed irradiance value, particularly near sunrise and sunset or under cloudy skies. Calculations performed for Ushuaia showed that, on very cloudy days, supplementation by the square-wave method may produce unrealistic irradiances. Differences between the spectra of the calculated supplementing irradiance and the lamp for a given site and date will be a function of the time of day and may become more or less pronounced according to the biological weighting function of the effect under study.

Canada↗
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Parkinson's disease.

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Antiparkinson Agents↗