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Biomedical subjects

A Kumar

Publications and source records attributed to A Kumar.

At least 919 records · Page 51Linked to original sources
PubMed1996

Seronegative spondyloarthropathies and HLA-B27 subtyes: a study in Asian Indians.

In this study, 60 HLA-B27+ve SSA patients and 17 healthy controls belonging to North India were analyzed to ascertain heterogeneity of the B27 molecule in this population. ID-IEF and PCR-SSOP technologies were used to analyze polymorphism in exon 2 and 3 of the HLA-B27 gene. Four different subtypes were encountered: B*2702,04,05 and 07. Other subtypes of B27 viz B*2701,03,06 and 08 were not encountered. B*2704 (common oriental subtype) and B*2705 (common Caucasian subtype) were the most common subtypes in the control and patient groups. B*2707 was less frequently encountered in both groups and B*2702 was found in only one AAU patient. B*2704 was the predominant subtype in the AS group (70.8%) compared to its frequency of 47% in healthy controls (RR = 2.73) while in the undiff SpA group, B*2705 occurred most frequently (73.1%, RR = 3.05). B27 subtypes segregated differently in males and females. 12 of the 17 male AS patients carried B*2704 as compared to 1 of 8 healthy males (X2 = 3.9, P < 0.05). On the other hand, in the undiff SpA, B*2705 was significantly raised in female patients (100%) as compared to healthy females (22.2%, X2 = 4.9, P < 0.05). Subtype distribution is indicative of racial admixture in the Asian Indian population.

Case-Control Studies↗
PubMed1996

Cardiovascular effects of centrally administered endothelin-1 and its relationship to changes in cerebral blood flow.

Intracerebroventricular (i.c.v.) injection of endothelin-1 (ET-1; 100 ng. i.c.v.) produced an initial pressor (24%) (peak at 3 min following ET-1 administration) and a delayed depressor (-40%) (30 and 60 min following ET-1 administration) effects in urethane anesthetized rats. The pressor effect of ET-1 was due to an increase (21%) in cardiac output, while the depressor effect of ET-1 was associated with a marked decrease (-46%) in cardiac output. Stroke volume significantly decreased at 30 and 60 min after the administration of ET-1. No change in total peripheral vascular resistance and heart rate was observed following central administration of ET-1. The effects of ET-1 on Blood pressure, cardiac output and stroke volume were not observed in BQ123 (10 micrograms, i.c.v.) treated rats. Blood flow to the cerebral hemispheres, cerebellum, midbrain and brain stem was not affected at 3 min, but a significant decrease in blood flow to all the regions of the brain was observed at 30 and 60 min following central administration of ET-1. BQ123 pretreatment completely blocked the central ET-1 induced decrease in blood flow to the brain regions. It is concluded that the pressor effect of centrally administered ET-1 is not accompanied by a severe decrease in brain blood flow, however, a subsequent decrease in blood pressure is associated with a decrease in blood flow to the brain. The cardiovascular effects of ET-1 including decrease in brain blood flow are mediated through central ET receptors.

Animals↗
PubMed1996

Modification of systemic and regional circulatory effects of intracerebroventricular administration of endothelin-1 by propranolol in anesthetized rats.

1. Cardiovascular effects of centrally administered endothelin-1 (ET-1) were studied in control and propranolol-treated anesthetized rats using a radioactive microsphere technique. 2. In the control group, blood pressure, cardiac output, and stroke volume were decreased, and heart rate was not altered after the administration of ET-1.ET-1 produced a reduction in blood flow to the brain, heart, kidneys, gastrointestinal tract, portal system, musculoskeletal system, and skin. 3. Propranolol significantly attenuated the decrease in blood pressure, cardiac output and stroke volume induced by centrally administered ET-1. The reduction in blood flow to the brain, heart, kidneys, gastrointestinal tract, portal system, musculoskeletal system and skin induced by centrally administered ET-1 was blocked by propranolol. 4. It is concluded that centrally administered ET produces significant cardiovascular effects which are mediated through the sympathetic nervous system and could be antagonized by propranolol. These findings can also be helpful in explaining some of the beneficial effects of propranolol in various cardiovascular disorders involving central ET mechanisms.

Adrenergic beta-Antagonists↗
PubMed1996

Benign esophageal strictures in children and adolescents: etiology, clinical profile, and results of endoscopic dilation.

BACKGROUND: The problem of dysphagia in children and adolescents differs from that in adults, and therefore requires special consideration. METHODS: Forty-one consecutive children and adolescents 16 years of age or younger (mean, 7.2 years), with benign esophageal strictures were evaluated in a prospective manner over a 7-year period. The most frequent causes of esophageal strictures were caustic ingestion and complications of endoscopic sclerotherapy of esophageal varices. Dilation was done on a weekly basis using bougies and was considered adequate if the esophageal lumen could be dilated to 15 mm diameter (11 mm in children less than 5 years old) with complete relief of dysphagia. RESULTS: Of the 30 patients who could be adequately followed after initial dilation, 16 had corrosive strictures and 14 had strictures due to other causes. Patients with corrosive strictures required a significantly higher number of sessions for adequate initial dilation (7.8 +/- 2.5 sessions vs 1.86 +/- 0.48 sessions; p < 0.01). Patients with corrosive strictures had a higher number of mean symptomatic recurrences per patient month as compared to the noncorrosive stricture group (0.15 +/- 0.01 vs 0.087 +/- 0.03, p < 0.01). Six esophageal perforations occurred during a total of 327 dilation sessions (1.8%); there was one fatality. CONCLUSIONS: From our experience, we conclude that benign esophageal strictures in young patients can be treated effectively and with acceptable safety by means of endoscopic dilation.

Adolescent↗
PubMed1996

Academicians' attitudes and beliefs towards anti-smoking measures.

Academic staff of Lucknow University (India) and its various faculties were questioned to know their attitudes and beliefs regarding various anti-smoking measures, using a questionnaire based on WHO guidelines. Of the male teachers 21.4% were current smokers and 12.3% were ex-smokers. Non-smokers were in greater agreement with various anti-smoking measures than current and ex-smokers, while more females-all of whom were non-smokers-than their male counterparts supported these measures. Endorsement of various anti-smoking measures differed from group to group, however, academicians agreed most with the notion that "Everybody has a right to breath air free of tobacco smoke'. "Sale of tobacco completely banned' was the measure opposed by most of the academicians. "Preventing diseases' and "Religious reasons' were, respectively, the most and least important motives for not smoking.

Adult↗
PubMed1996

Fibrillary glomerulonephritis related to serum fibrillar immunoglobulin-fibronectin complexes.

Fibrillary glomerulonephritis is a disease of uncertain origin and pathogenesis characterized by nonamyloidotic fibrils in glomeruli. We report immunohistological, immunochemical, and biochemical studies of a serum fibrillar cryoprecipitate obtained from a patient with fibrillary glomerulonephritis, that formed on prolonged storage at 4 degrees C. By Western blot and amino acid sequence analysis, the cryoprecipitated fibril components consisted of immunoglobulins, heavy chains gamma and mu, light chains kappa and lambda, and fibronectin, similar to the proteins identified by immunofluorescence and immunoelectron microscopy in the glomerular fibrils. These findings support the hypothesis that serum precursors may be the source of the fibrillar deposits and suggest a role for immunoglobulin-fibronectin complexes in the pathogenesis of fibrillary glomerulonephritis.

Antigen-Antibody Complex↗
PubMed1996

Prolapsing gastric polyp, an unusual cause of gastric outlet obstruction: a review of the pathology and management of gastric polyps.

Gastric polyps are rare and largely asymptomatic, but attract importance because of their strong potential to progress to carcinoma. Rarely, pedunculated polyps arising in the antrum may prolapse through the pylorus, causing intermittent gastric outlet obstruction. We describe here our experience of four cases collected over a ten-year period, each presenting dissimilarly with this phenomenon. We review the literature referring to the pathogenesis of gastric polyps and their association with malignancy and other disorders. We proceed to discuss the efficacy of barium studies versus gastroscopy in detecting these lesions, the relative roles and merits of endoscopic polypectomy and surgery, and the importance of prolonged follow-up of patients harbouring gastric polyps.

Aged↗
PubMed1996

Modulatory influence of alcoholic extract of Ocimum leaves on carcinogen-metabolizing enzyme activities and reduced glutathione levels in mouse.

The present study reports the modulatory influence of alcoholic extract from the leaves of Ocimum sanctum on the activities of cytochrome p-450, cytochrome b5, and aryl hydrocarbon hydroxylase enzymes in the liver and glutathione-S-transferase and reduced glutathione level in the liver, lung, and stomach of the mouse. Oral treatment with the leaf extract at 400 and 800 mg/kg body wt for 15 days would significantly elevate the activities of cytochrome p-450 (p < 0.05), cytochrome b5 (p < 0.01, p < 0.001), aryl hydrocarbon hydroxylase (p < 0.05), and glutathione S-transferase (p < 0.05, p < 0.01), all of which are important in the detoxification of carcinogens as well as mutagens. Moreover treatment with 400 and 800 mg/kg body wt of Ocimum extract for 15 days also significantly elevated extrahepatic glutathione-S-transferase (p < 0.05, p < 0.01). The reduced glutathione level was also elevated by treatment with the leaf extract in liver, lung, and stomach tissues (p < 0.01, p < 0.001). Mice fed a diet containing 0.75% butylated hydroxyanisole (positive control) revealed no alteration in the basal hepatic cytochrome p-450 and aryl hydrocarbon hydroxylase level, but hepatic cytochrome b5 and glutathione S-transferase activity in hepatic and extrahepatic organs were elevated in a time-responsive manner (p < 0.05, p < 0.001). The observations suggest further exploitation of the Ocimum leaf extract or its active principle(s) for the chemoprevention of chemical carcinogenesis in different animal model systems.

Animals↗
PubMed1996

Cloning of mouse integrin alphaV cDNA and role of the alphaV-related matrix receptors in metanephric development.

Metanephrogenesis has been a long-standing model to study cell-matrix interactions. A number of adhesion molecules, including matrix receptors (i.e., integrins), are believed to be involved in such interactions. The integrins contain alpha and beta s ubunits and are present in various tissues in different heterodimeric forms. In this study, one of the members of the integrin superfamily, alphaV, was characterized, and its relevance in murine nephrogenesis was investigated. Mouse embryonic renal cDNA libraries were prepared and screened for alphaV, and multiple clones were isolated and sequenced. The deduced amino acid sequence of the alpha-v cDNA clones and hydropathic analysis revealed that it has a typical signal sequence and extracellular, transmembrane, and cytoplasmic domains, with multiple Ca2+ binding sites. No A(U)nA mRNA instability motifs were present. Conformational analysis revealed no rigid long-range-ordered structure in murine alphaV. The alphaV was expressed in the embryonic kidney at day 13 of the gestation, with a transcript size of approximately 7 kb. Its expression increased progressively during the later gestational stages and in the neonatal period. It was distributed in the epithelial elements of developing nephrons and was absent in the uninduced mesenchyme. In mature metanephroi, the expression was relatively high in the glomeruli and blood vessels, as compared to the tubules. Various heterodimeric associations of alphaV, i.e., with beta1, beta3, beta5, and beta6, were observed in metanephric tissues. Inclusion of alphaV-antisense-oligodeoxynucleotide or -antibody in metanephric culture induced dysmorphogenesis of the kidney with reduced population of the nephrons, disorganization of the ureteric bud branches, and reduction of mRNA and protein expressions of alphaV. The expressions of integrin beta3, beta5, and beta6 were unaltered. These findings suggest that the integrin alphaV is developmentally regulated, has a distinct spatio-temporal expression, and is relevant in the mammalian organogenesis.

Amino Acid Sequence↗
PubMed1996

Evaluation of Bcl-2/B cell transgenic mice (B6) for hybridoma production.

Bcl-2 is an oncogene associated with prevention of apoptosis in a variety of cell types. Bcl-2 expression in B lymphoid cells prolongs antibody production, in vitro and in vivo. A line of transgenic mice (B6) has been developed that expresses human Bcl-2 in the B cells of SWR/SJL mice. B6 transgenic, nontransgenic littermates, and BALB/c mice were immunized with beta-galactosidase (B-gal) or sheep red blood cells (SRBC). The number of spleen cells recovered from immunized B6 mice was 3-4 times greater than syngeneic, nontransgenic littermates or BALB/c mice. Spleen cells from B-gal or SRBC immune B6, SWR/SJL, and BALB/c mice were fused with P3 myeloma cells to produce hybridomas. Forty-eight percent of the wells plated with fused B6 spleen cells produced B-gal-specific antibodies compared to 14% from BALB/c and 12% from SWR/SJL. Antibody-specific wells were subcloned, resulting in enhanced recovery of antigen-specific subclones with B6-derived fusions compared to controls. In the SRBC fusions, 17% of the wells plated with fused B6 spleen cells produced SRBC-specific antibodies compared to 6% for BALB/c and SWR/SJL spleens. After subcloning, B6-derived clones produced 8% positive subclones compared to 9.5% from SWR/SJL and 3.5% from BALB/c. Comparison of the isotype distribution of subclones showed a higher ratio of IgG antibodies compared to IgM from B6 mice in the B-gal fusions. IgA antibodies were recovered only from B6 mice. These data indicate that B6 transgenic mice that overexpress Bcl-2 in their B cells may be superior to other mouse strains for production of antigen-specific hybridomas.

Animals↗
PubMed1996

Expression of intracellular interferon constitutively activates ISGF3 and confers resistance to EMC viral infection.

The mechanism(s) by which interferon (IFN)-alpha confers resistance to viruses is currently being characterized. Previous studies have shown that binding of IFN-alpha to its high-affinity receptor activates transcription factor interferon-stimulated gene factor 3 (ISGF3), which positively regulates a number of antiviral genes including 2'-5'-oligoadenylate synthetase (2-5A synthetase). We show that mouse L cells expressing nonsecreted (intracellular) type I human IFN are less susceptible to encephalomyocarditis (EMC) virus infection and have increased levels of 2-5A synthetase. The 2-5A synthetase promoter is constitutively induced, and the antiviral effects are most likely mediated through activation of ISGF3, which occurs constitutively in cell lines expressing intracellular interferon. These data suggest that the internalization of IFN-alpha may play a role in the antiviral properties associated with IFN.

2',5'-Oligoadenylate Synthetase↗
PubMed1996

Morbidity and mortality of laparoscopic cholecystectomy in an institutional setup.

Laparoscopic cholecystectomy (LC) though a very safe operative procedure does have its own morbidity and mortality. The present study was undertaken to analyze the morbidity and mortality of this procedure in an institutional setting. Between October 1992 and October 1995 a total of 433 patients received LC. Conversion to open cholecystectomy was required in 62 patients (14.3%). The decision to convert was made because the surgeon was forced to convert (3.7%) or the conversion was the operator's choice (10.6%). There was no difference in the conversion rate of consultants versus residents (14.4% vs. 14.2%). Major intraoperative and postoperative morbidity was encountered in 8.3% of patients. One patient required reexploration. The incidence of common bile duct (CBD) injury was 2.5%. There was no operative or 30 days mortality. However, two patients died in the follow-up period due to procedure-related complications. Low threshold for conversion, early recognition of morbidity, and prompt and judicious management of such complications under guided supervision is necessary in order to avoid major postoperative problems. The experience in a teaching hospital training program is different from that of an individual surgical setup.

Adolescent↗
PubMed1996

Oncocytic nodular hidradenoma.

Oncocytic neoplasms are most commonly of salivary, thyroid, parathyroid, and renal origin. Ocular adnexal tumors with oncocytosis have been reported. We report an unusual example of a skin adnexal tumor from the back. A tumor of uncertain duration was excised from a 54-year-old man. Light microscopy of hematoxylin and eosin-stained sections showed a large, fairly well-defined cystic nodular hidradenoma with areas infiltrated by numerous closely arranged, large, uniform, oval and polygonal cells with abundant intensely eosinophilic cytoplasm and small central, dark, round nuclei. No significant cellular atypia or mitotic figures were observed. The cytoplasm of these cells showed markedly positive immunostaining with monoclonal antimitochondrial antibodies. Electron microscopy demonstrated cytoplasm packed with mitochondria. Pure oncocytic tumors usually follow a benign clinical course. The focal presence of oncocytes in an otherwise histologically recognizable tumor apparently does not affect the prognosis, which in this case is the favorable outcome expected for a nodular hidradenoma.

Adenoma, Oxyphilic↗
PubMed1996

Candida overgrowth after treatment of duodenal ulcer. A comparison of cimetidine, famotidine, and omeprazole.

Acid-reducing drugs can cause increased growth of microbes, including fungus, because of high gastric pH. Our purpose was to evaluate the occurrence of mycotic infection in patients with duodenal ulcer on anti-ulcer therapy and to compare the effects of cimetidine, famotidine, and omeprazole. Eighty patients with duodenal ulcer (62 males and 18 female patients, 16-65 years old) were evaluated for mycotic infection before and after 6 weeks of therapy (cimetidine, 20 patients; famotidine, 40 patients; omeprazole, 20 patients). Mycotic infection was diagnosed by endoscopic biopsy from the ulcer edge subjected to smear, culture, and histopathology and by endoscopic brush samples and gastric aspirate. On the basis of these studies, patients were categorized as having no fungal growth, saprophytic growth, or significant fungal growth. Thirty-five (43.8%) patients had evidence of fungus before ulcer therapy, and 16 of the 35 (20%) had significant fungal growth. The fungal isolation rate was higher in older patients (> and = 45 years of age) and in those with an ulcer size > and = 2 cm. While there was no significant increase in the total number of patients with evidence of fungus after therapy (n = 36), there was a significant increase in those with significant growth (n = 27, p < 0.05) compared with pretreatment status. We found that posttreatment gastric pH of > and = 4 was associated with a higher fungal positivity rate (59.4%) than pH values < 4 (32.4%, p < 0.05). However, neither the type of drug used nor the response in terms of ulcer healing correlated with the presence of fungus. Regardless of the type of drug used, acid-reducing therapy is associated with increased significant fungal growth.

Adult↗
PubMed1996

Intravenous amiodarone for therapy of atrial fibrillation and flutter in critically ill patients with severely depressed left ventricular function.

A retrospective review was done to determine the efficacy and hemodynamic effects of slow intravenous amiodarone administration on invasively monitored patients with acute onset of atrial fibrillation or atrial flutter and left ventricular ejection fractions < 15%. Eight patients met predefined inclusion criteria. All received 300 mg amiodarone intravenously over 1 hour. Seven reverted to sinus rhythm within 1 hour, with return of most hemodynamic variables to baseline. Before reversion, each patient experienced a beneficial slowing of heart rate (mean, 28%) resulting in significant improvement of stroke volume index (mean, 49%) and left ventricular stroke work index (mean, 61%). No patient had hemodynamic deterioration attributable to amiodarone infusion. Slow intravenous infusion of amiodarone appears to be an effective and hemodynamically well-tolerated therapy for atrial fibrillation and atrial flutter in critically ill patients with marked depression of left ventricular systolic function.

Acute Disease↗
PubMed1996

A porcine model of peritonitis and bacteremia simulates human septic shock.

Cardiovascular responses to systemic bacteremia were evaluated in a pre-instrumented, conscious pigs. Basal observations were obtained 5-7 days after instrumentation. On the next day, Escherichia coli 0111.B4 (1.1 to 33 x 10(9) CFU/kg)-laden fibrin clots were implanted intraperitoneally. Nonsurvivors (9/18) demonstrated rapid cardiovascular decompensation. Survivors (9/18) demonstrated significant cardiovascular injury, which was reversed by 5-7 days postimplant. Cardiac inotropicity was significantly reduced in this period, but recovered by day 7. Circulating myocardial depressant substance activity (assayed by serum-induced depression of beating neonatal rat myocytes) was present on days 1-4 of bacteremia and recovered to basal values on day 6. No clinical or cardiovascular changes were seen in pigs implanted with sterile clots (n = 4). These data demonstrate that implantation of bacteria-laden fibrin clots in pigs induces cardiovascular alterations that mimic responses seen in human sepsis.

Animals↗