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S Choudhary

Publications and source records attributed to S Choudhary.

At least 55 records · Page 3Linked to original sources
PubMed1999

Ethanol-induced barrier dysfunction and its prevention by growth factors in human intestinal monolayers: evidence for oxidative and cytoskeletal mechanisms.

Exposure of intestinal mucosa to ethanol (EtOH) disrupts barrier function and growth factors [epidermal growth factor (EGF) and transforming growth factor-alpha (TGF-alpha)] are protective, but the mechanisms remain obscure. Accordingly, we sought to determine whether the molecular mechanism of EtOH-induced intestinal barrier dysfunction involves oxidative stress and disassembly of microtubules and whether the mechanism of protection by EGF or TGF-alpha involves prevention of these alterations. To this end, human colonic (Caco-2) monolayers were exposed to 0 to 15% EtOH with or without pretreatment with EGF or TGF-alpha (10 ng/ml) or with oxidative or cytoskeletal modulators. Effects on cell viability, barrier function, tubulin (microtubules), and oxidative stress were then determined. Cells were also processed for immunoblots of polymerized tubulin (S2; index of stability) and the monomeric tubulin (S1; index of disruption). EtOH dose-dependently decreased the stable S2 polymerized tubulin and concomitantly increased measures of oxidative stress, including oxidation and nitration of tubulin, fluorescence of dichlorofluorescein, and inducible nitric oxide synthase activity. EtOH also dose-dependently disrupted barrier function and extensively damaged microtubules, and these effects were prevented by pretreatment with antioxidant scavengers: L-cysteine, superoxide dismutase, and L-N(6)-1-iminoethyl-lysine (an inducible nitric oxide synthase inhibitor). In monolayers exposed to EtOH, pretreatment with EGF or TGF-alpha prevented the oxidation and nitration of tubulin, increases in the levels of the unstable S1 tubulin, disruption of microtubules, and barrier dysfunction. A microtubule stabilizer (paclitaxel,Taxol) mimicked, in part, the effects of EGF and TGF-alpha, whereas a microtubule disruptive drug (colchicine) prevented the protective effects of these growth factors. We concluded that mucosal barrier dysfunction induced by EtOH involves oxidative stress, which causes the disassembly of the microtubule cytoskeleton. Protection by EGF and TGF-alpha involves the prevention of these EtOH-induced alterations in microtubules.

Antioxidants↗
PubMed1998

Umbilicosculpture: a concept revisited.

After birth the umbilicus is the only naturally formed visible scar on the body. To reconstruct a neo-umbilicus following abdominoplasty various local interposition flaps have been described to circumvent a circular scar contracture and to recreate a superior hood. The additional scarring with these techniques can give an operated look to the neo-umbilicus. The importance of gravity in the formation of a superior hood is highlighted and the issue of circular scar contractures is addressed. Emphasis is placed on sculpturing the peri-umbilical fat to enhance contour and on placing the circular scar deep in the neo-umbilicus.

Contracture↗
PubMed1998

Prevalence and pattern of psychiatric morbidity in children.

Present study was carried out at child guidance clinic of Guru Teg Bahadur Hospital, Delhi. Sample consisted of 300 children (175 boys and 125 girls of aged 2-12 years) from November, 1994 to October, 1996. Diagnoses were made by using ICD-10 criteria. The major diagnoses were mental retardation (20.6%), epilepsy (20%), hysterical conversion reaction (6.3%), ADHD (5%) and childhood depression (6%).

Child↗
PubMed1996

Measurement of faecal alpha 1-antitrypsin: methodologies and clinical application.

Presence of the serum protein, alpha 1-antitrypsin, in the faeces is a potentially useful marker for gastrointestinal disease and/or blood loss. In an effort to simplify faecal sampling procedures, we evaluated the performance of measuring alpha 1-antitrypsin in eluants of thin smears of faeces made on filter paper, relative to conventional measurement in aqueous extracts of stool. Faecal specimens and smears were collected from healthy subjects (n = 22) and from patients with gastrointestinal bleeding (n = 12) or inflammation (n = 22), colorectal neoplasia (n = 15), or miscellaneous diseases with a low risk of excessive faecal protein loss (n = 30). alpha 1-Antitrypsin was measured by ELISA and haem porphyrins (as a measure of blood loss) by HemoQuant. Results from smears were highly correlated (r = 0.81; P < 0.001) with faecal alpha 1-antitrypsin. The smear method detected an elevated faecal alpha 1-antitrypsin with 93% specificity and 75% sensitivity. Sensitivity was high ( > 88%) where levels were markedly elevated in inflammatory and bleeding groups and low ( < 62%) where abnormal levels were mildly elevated (neoplasia and miscellaneous groups). Elevated alpha 1-antitrypsin detection by either method positively predicted > 90% of patients with gastrointestinal inflammatory disease when levels were elevated 6-fold and 1.5-fold or more, respectively. In 15 patients with colorectal neoplasia, faecal alpha 1-antitrypsin was elevated in 10 patients, haem porphyrins in nine patients and either in 12; however, smear eluant levels were elevated in only six patients. Blood loss was probably a major contributor to elevated faecal alpha 1-antitrypsin in some patients but not in the inflammatory group as a whole. The sampling and aesthetic advantages of the smear eluant method are offset by reduced sensitivity, precluding its use as a screening test for colorectal neoplasia. However, its performance in predicting inflammatory disease is equivalent to that of conventional measurement and warrants a prospective evaluation as an early investigative test. Concurrent evaluation of blood loss may improve its interpretation.

Adolescent↗
PubMed1995

Modulation of primary antibody response by protein A in tumor bearing mice.

Protein A (PA) is a cell wall glycoprotein of Staphylococcus aureus Cowan I, which possess a number of immunomodulatory and antitumor properties. We have previously shown that PA suppresses the anti-sheep erythrocyte primary antibody response in normal mice. The present investigation evaluates the effect of protein A on the anti-sheep erythrocyte primary antibody response in tumor-bearing mice. The primary antibody response in tumor-bearing mice immunized with sheep red blood cells (SRBC) was suppressed by the intraperitoneal administration of PA in a dose-dependent fashion. The plaque forming cell (PFC) assay was used to assess this response. Maximum suppression of the PFC response was observed at 12 micrograms PA/animal (p < 0.001) and could be observed at doses as low as 1 microgram PA/animal (p < 0.01). The amount of suppression was proportional to the number of PA doses administered. In addition this effect was critically dependent on the timing of PA administration. PA showed no significant effect on PFC when injected after immunization, but it produced pronounced suppression when injected prior to the immunization with SRBC. Maximum suppression of the PFC response was observed when PA was administered one day before the antigen challenge. PA also reduced splenic localization of 51Cr labeled SRBC to 42% (p < 0.01). The altered localization of antigen in spleen may be responsible for reduced PFC response in tumor-bearing mice. Depletion of B-lymphocyte is reported to exhibit tumor inhibition. Therefore, we propose that the suppression of the primary antibody response by PA helps in tumor regression by reducing the soluble immunosuppressive immune complexes.

Animals↗
PubMed1992

Visualization of myocardial cellular architecture using acoustic microscopy.

The resolution of an ultrasound transducer depends on its frequency. The resolution improves when higher frequency transducers are used. A 1000 MHz transducer has a resolution of approximately 1 micron. Acoustic microscopy utilizes very high-frequency ultrasound (600 to 1000 MHz) to visualize structures on a microscopic level. Unstained, deparaffinized, 5 microns sections of myocardial biopsy specimens from 10 patients were placed on a slide and imaged using an Olympus UH3 scanning acoustic microscope. To compare with light microscopy, the section used for acoustic microscopy was subsequently stained with hematoxylin and eosin and a serial section from the paraffin block was stained with PTAH stain. Myocytes, myofibrils, and interstitial tissue were accurately imaged. Pathologic phenomena such as cell fallout, interstitial fibrosis, and lymphocytic infiltration were identified by acoustic microscopy. Intramural vessels, nuclei of endothelial cells, and the media were clearly identified by this technique. There was close correlation between findings by acoustic microscopy and light microscopy. Acoustic microscopy permitted the visualization of cardiac cellular detail with a resolution similar to that of light microscopy. Unlike light microscopy, acoustic microscopy requires no staining of the specimen.

Biopsy↗
PubMed1990

Apert's disease.

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Acrocephalosyndactylia↗