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Biomedical subjects

A Chowdhury

Publications and source records attributed to A Chowdhury.

At least 73 records · Page 4Linked to original sources
PubMed1995

The expression of IL-2, IL-4 and interferon-gamma (IFN-gamma) mRNA using liver biopsies at different phases of acute exacerbation of chronic hepatitis B.

To investigate the hypothesis that Th1 phenotype cytokines are associated with the increasing activity of hepatitis and Th2 phenotype cytokines with decreasing activity in the liver of chronic viral hepatitis, expressions of the mRNA of the cytokines IL-2, IFN-gamma and IL-4 in the liver of 23 patients with chronic hepatitis B were investigated by reverse transcription polymerase chain reaction. Patients were divided into three groups according to the phase of acute exacerbation of hepatitis as increasing (n = 9), decreasing (n = 8), and stable phase (n = 6). Both IL-2 and IFN-gamma mRNA were preferentially expressed in increasing phase than in decreasing phase (P < 0.01, P < 0.05, respectively) and associated with the high serum alanine aminotransferase (ALT) level. On the other hand, IL-4 mRNA was detected in decreasing phase with significant frequency compared with increasing phase (P < 0.05). However, expression of IL-4 mRNA was not associated with serum ALT level. Our results suggest that Th1 phenotype cytokines up-regulate and Th2 phenotype cytokines down-regulate the liver inflammation of chronic viral hepatitis.

Adolescent↗
PubMed1995

Cytokines in the stools of children with complicated shigellosis.

The pathogenesis of the systemic complications, leukemoid reaction and hemolytic uremic syndrome, associated with Shigella dysenteriae type 1 infection is not well understood. The excessive production of proinflammatory cytokines, including tumor necrosis factor alpha (TNF-alpha) and interleukin 6 (IL-6), has been suggested as a possible factor. We measured IL-6 and TNF-alpha in stools of 56 children with S. dysenteriae 1 infection and 29 children without any apparent infection, all age 12 to 60 months. Sixteen children with S. dysenteriae 1 infection had leukemoid reaction or hemolytic uremic syndrome (complicated shigellosis), while the others did not (uncomplicated shigellosis). Stool IL-6 and TNF-alpha concentrations were higher in children with uncomplicated shigellosis than in children with complicated shigellosis (P = 0.009 and < 0.001, respectively) or in uninfected children (P < 0.001). It is concluded that complicated infection is not associated with higher concentrations of the proinflammatory cytokines IL-6 and TNF-alpha in stool.

Child, Preschool↗
PubMed1995

Evaluation of the monoclonal antibody-based kit Bengal SMART for rapid detection of Vibrio cholerae O139 synonym Bengal in stool samples.

A monoclonal antibody-based test, Bengal SMART, was developed for rapid detection of Vibrio cholerae O139 synonym Bengal directly from stool specimens. The test, which takes about 15 min to complete, was used to screen 189 diarrheal stool specimens. The results were compared with those of a monoclonal antibody-based coagglutination test (COAT) and the conventional culture methods used as the "gold standard" for detection of V. cholerae O139. The Bengal SMART test showed a sensitivity of 100% and a specificity of 97% in comparison with the gold standard. It also fared better than COAT, which had a sensitivity of 96% for rapid detection of V. cholerae O139 synonym Bengal. These results show that Bengal SMART is suitable for use in field settings for rapid diagnosis of cholera caused by V. cholerae O139.

Agglutination Tests↗
PubMed1994

Monoclonal antibodies specific for Shigella dysenteriae serotype 13. Production, characterization, and diagnostic application.

Three mouse monoclonal antibodies (mAbs) (ICL3, ICL4, and ICL5) were produced that specifically recognized the lipopolysaccharide antigen of the newly recognized Shigella dysenteriae serotype-13 strain. All three mAbs reacted with all nine reference isolates of S. dysenteriae 13 in different tests. The mAbs also detected colonies of S. dysenteriae-13 isolates by direct slide agglutination test. The mAbs also reacted with the reference Escherichia coli 0150 strain and showed its close antigenic relationship with S. dysenteriae 13. Use of these mAbs in our clinical laboratory during an 8-month period detected three S. dysenteriae-13 isolates that were also detected by a polyclonal rabbit antiserum. It should now be possible to define the epidemiologic importance of S. dysenteriae serotype 13 in diarrhea by using these mAbs.

Agglutination Tests↗
PubMed1994

Production, characterization, and application of monoclonal antibodies to Vibrio cholerae O139 synonym Bengal.

Mouse monoclonal antibodies (MAbs) were derived against acetone-treated whole cells of the newly recognized Vibrio cholerae O139 serogroup which is causing epidemics of cholera-like disease in India and Bangladesh. Four MAbs specifically recognized the lipopolysaccharide antigens of V. cholerae O139. MAbs ICL9 and ICL13 were of the immunoglobulin M (IgM) isotype, ICL11 was of the IgG3 isotype, and ICL12 was of the Ig2b isotype. A fifth MAb, ICL10, of the IgG2b isotype cross-reacted with V. cholerae O91. All five MAbs recognized V. cholerae O139 in an enzyme-linked immunosorbent assay, slide agglutination test, motility inhibition test, and indirect immunofluorescence test. During a 1-month evaluation of these MAbs in our clinical laboratory, all 86 cases diagnosed as V. cholerae O139 by a rabbit polyclonal antiserum were also detected by these MAbs, establishing their utility as highly sensitive and specific diagnostic reagents. With these MAbs, it should now be possible to screen for the V. cholerae O139 serogroup in epidemic and endemic diarrhea cases and in environmental and food samples.

Agglutination Tests↗
PubMed1994

Development and evaluation of rapid monoclonal antibody-based coagglutination test for direct detection of Vibrio cholerae O139 synonym Bengal in stool samples.

A monoclonal antibody-based coagglutination test directly detected Vibrio cholerae O139 synonym Bengal in 83 of 120 watery diarrheal stool specimens; on culture, 90 samples were positive. Thus, with 92% sensitivity, 100% specificity, and 100% positive and 95% negative predictive values, the coagglutination test is a useful rapid test for V. cholerae O139.

Agglutination Tests↗
PubMed1991

Evaluation of indigenous plants in the treatment of acute shigellosis.

The clinical efficacy of three indigenous plants was compared with that of ampicillin and placebo in a randomized double blind clinical trial. Eighty-two men with shigellosis were studied. Sixteen patients received dried unripe fruit powder of 'bel' (Aegle marmelos), 19 received dried powdered plant of 'thankuni' (Hydrocotyle asiatica), 15 received a similar preparation of 'gandhavadulia' (Paederia foetida), 15 received ampicillin and 17 received a placebo. Treatment with indigenous plants did not show any clinical improvement or bacteriological cure as compared to ampicillin. The natural history of shigellosis was obtained by documenting the response of the indigenous plants and placebo treated groups.

Adolescent↗
PubMed1990

Detection of cellular retinoic acid-binding protein in chick embryonic tissues by monoclonal antibodies.

We describe the production of monoclonal antibodies (MAbs) directed against cellular retinoic acid-binding protein (CRABP) and their application for the quantitation and localization of CRABP during the development and growth of chick embryo. Three MAbs, classified as D-10 and H-6 (IgG1-isotype), and G-4 (IgM-isotype), exhibited the highest degree of immunoreactivity for chick embryo CRABP. The antibodies showed partial reactivity to CRABP from rat testis. None of the MAbs showed cross-reactivity with cellular retinol-binding protein or fatty acid-binding protein which are structurally similar to CRABP. The antigen-specificity was confirmed by immunoblot analysis as well as by fast protein liquid chromatographic analysis. The radioimmunoassay developed for MAb (D-10) provided a detectability range of 0.5-5.0 ng of CRABP in the standard displacement curves. An abundance of CRABP was found in embryonic skin, brain, testis and eye. Several other tissues (heart, lung, liver), previously reported to have undetectable levels of CRABP, showed significant amounts of the binding protein. The levels of CRABP peaked in early (4-6-day-old) and late (11-14-day-old) stages of embryo development. Immunolocalization of CRABP in chick embryo skin demonstrates a specific intense staining for the antigen in the dense areas of mesenchyme cells (mesodermal layers); little or no staining was apparent in the differentiated cells of epidermis and peridermis as well as in the loose connective tissues. The MAbs are useful not only in the purification of CRABP as an affinity adsorbent, but also in the elucidation of the possible role of CRABP in the transfer of the ligand to its nuclear receptors and in the morphogenetic gradient formation of RA in chick embryo tissues.

Animals↗
PubMed1990

Gardnerella vaginalis: isolation and identification.

A total of 26 isolates of Gardnerella vaginalis were obtained from 248 patients attending the out patient department of Obstetrics and Gynaecology at A.I.I.M.S hospital, over a period of one year. The vaginal discharge of these patients was cultured on five different media in order to evaluate the best medium for the growth of G. vaginalis. Media containing human blood were found to be the most suitable, Human-Blood-Bilayer medium with Tween-80 being the best for the growth of the organism. A total of 12 biochemical tests were performed for the identification of each isolate. A short and rapid scheme for identification of the organism in a routine laboratory has been evolved.

Culture Media↗
PubMed1989

Characterization and serial propagation of mouse prostate epithelial cells in serum-free medium.

Epithelial cell cultures derived from the ventral prostate of normal adult mice have been propagated in serum-free medium. The cultures were initiated and maintained in Ham's F-12 nutrient mixture supplemented with insulin (5 micrograms/ml), EGF (10 ng/ml), hydrocortisone (0.5 micrograms/ml), cholera toxin (10 ng/ml), bovine pituitary extract (25 micrograms protein/ml) and antibiotics. The cells exhibited microvilli on cell surfaces, interdigitations and junctional complexes including desmosomes between cells, and cytokeratins in cytoplasm which are characteristic of epithelial cells. In addition, the cells exhibited the tissue-specific markers, prostatic acid phosphatase and prostate-specific antigen.

Animals↗
PubMed1988

Uptake and cellular transport of [11-3H] all-trans-retinoic acid in the liver of vitamin A-deficient hamsters.

In this study, we examined, by ultrastructural autoradiography, the uptake and intracellular transport of [3H]all-trans-retinoic acid ([3H]RA) in the livers of vitamin A-deficient hamsters. Four-week-old animals were administered 25 microCi of [3H]RA by gavage, and, at different intervals thereafter, one animal was sacrificed. Their livers were excised and processed for autoradiography. Radioactive grains were observed to pass randomly through the plasma membrane by diffusion. No evidence of retinoid internalization by endocytosis was observed. Between 1 and 30 min after gavage, the radioactivity in parenchymal cells was associated mainly with rough endoplasmic reticulum (RER) and mitochondria. The labeling over nuclei was apparent at 1 min, remained relatively high up to 30 min, and subsequently decreased. At 2 and 5 hr, only a few grains were observed over nuclei, RER and mitochondria. At 24 hr, most of the labeling was associated with endothelial cells and sinusoidal spaces, indicating mobilization of [3H]RA from the liver. The results indicate that [3H]RA is transported through the plasma membrane by transmembrane diffusion without endocytosis and, after entering the cells, the ligand is rapidly translocated into nuclei.

Animals↗
PubMed1982

Partial optimization of electrochemical-etching parameters for highly sensitive CR-39 fast neutron dosimeters.

Voltage gradient and frequency were studied for their influence on the electrochemical etching of CR-39 plastic irradiated with fission spectrum, fast neutrons. A power supply having outputs of up to 1.5 kV (rms) and 5 kHz was used. Differential voltage measurements under non-etching conditions indicated that the optimal values in electrochemical etching with this power supply would be 20 kV/cm and 1.3 kHz. That these parameters produced a maximum sensitivity was verified in subsequent electrochemical etching experiments for a standard 4 hr in 9N KOH with foils that were both unirradiated and irradiated. The introduction of a proton irradiator cover and a conventional etching step prior to the electrochemical etching, increased the sensitivity to neutrons (approximately 30-fold) and decreased the background track density to 4.4 +/- 0.6 tracks/cm2. The corresponding sensitivity was then 1.3 tracks/cm2/mrem with a minimum level of detectability (3 sigma) of 1.4 mrem.

Electrochemistry↗