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Biomedical subjects

S Bandyopadhyay

Publications and source records attributed to S Bandyopadhyay.

At least 91 records · Page 5Linked to original sources
PubMed1993

CD4-independent infection of human peripheral blood dendritic cells with isolates of human immunodeficiency virus type 1.

Dendritic cells (DC) are members of a distinct family of bone marrow-derived leukocytes. DC are potent accessory cells for a number of T cell-mediated immune responses, including autologous and allogeneic mixed leukocyte reactions, and mitogen- and antigen-stimulated lymphocyte proliferation. In the present study, DC purified from human peripheral blood were inoculated with various strains (IIIB, SF2, WMJ1, SF162, 89.6 and clone HXB2) of human immunodeficiency virus type 1 (HIV-1) displaying different patterns of cellular tropism. Viral replication was demonstrated by detection of p24 antigen (Ag) intracellularly and in culture supernatants, and by Southern and Northern blot analyses for the presence of HIV DNA and RNA, respectively, within infected cells. Cell-free and cell-associated p24 Ag levels rose substantially when DC were inoculated with strains SF162, 89.6 and clone HXB2. In contrast, p24 Ag levels rose only marginally after inoculation of DC with strains IIIB, SF2 and WMJ1. Purified DC did not express detectable membrane CD4, although CD4 mRNA was detected by reverse transcriptase PCR. The presence of anti-CD4 monoclonal antibodies failed to block infection of DC by any of the HIV strains tested, suggesting the existence of a CD4-independent alternative pathway of viral entry. The possibility that DC serve as a reservoir for HIV-1 must be considered.

Adult↗
PubMed1993

IFN-gamma is directly cytostatic to the extracellular form (promastigote) of Leishmania donovani.

We investigated the effect of various human cytokines on the in vitro growth of Leishmania donovani (L. donovani) promastigotes. rhIFN-alpha, rhIFN-beta, rhIL-1, rhIL-2, rhIL-3, rhIL-4, rhIL-6 and rhM-CSF had no effect. By contrast, rhIFN-gamma was directly growth inhibitory to L. donovani promastigotes in a dose-dependent manner. Anti-IFN-gamma antibody, but neither anti-IFN-alpha nor anti-IFN-beta antibody, abolished this promastigote growth inhibitory effect of rhIFN-gamma. L. donovani promastigotes were not lysed by rhIFN-gamma as determined by 51Cr-release assay. These data indicate that rhIFN-gamma is cytostatic, not cytotoxic, to L. donovani promastigotes.

Animals↗
PubMed1993

Impairment of natural killer cell activity in Indian kala-azar: restoration of activity by interleukin 2 but not by alpha or gamma interferon.

Indian kala-azar patients have normal numbers of peripheral blood NK cells but impaired functional activity due to decreased binding and lysis of target cells. This impairment of NK activity could not be corrected by exogenous recombinant human alpha or gamma interferon. However, recombinant human interleukin 2 was able to restore this activity by augmenting conjugate formation and lysis of target cells.

Adolescent↗
PubMed1993

Epidemiological features of cholera outbreak in Delhi in 1988.

During 1988 a large scale outbreak of cholera occurred in Delhi giving rise to a total of 1708 bacteriologically proved El Tor cholera cases, the highest number recorded in a single year in Delhi, following its first detection in 1965. Civil lines and Shahdara zones were the worst affected areas recording 85.7 and 55.7 cases per 100,000 population respectively. The highest incidence rate was observed in the age group of 1-4 years (77 per 100,000). Males and females were equally affected. The data of moving average show the endemicity of cholera in Delhi with an increasing trend. The risk factors identified are lower socioeconomic status, poor personal hygiene, drinking water and food storage practices.

Adult↗
PubMed1993

An investigation of an outbreak of viral hepatitis in a residential area of Delhi.

Epidemiological investigation of a focal outbreak of jaundice in the KD block of Pitampura, Delhi during February-March 1992 revealed that 7.0 per cent of the population of the block suffered from viral hepatitis. There was no age or sex predilection. Epidemiological findings and Serological studies suggest that the epidemic was due to Hepatitis E (Enterically transmitted Non A and Non B) virus.

Adolescent↗
PubMed1993

Practices of preparation of oral rehydration solution among mothers reporting to the drug distribution centres in Delhi, India, 1992.

A study to assess the ability for preparing oral rehydration solution (ORS) correctly among the recipients of ORS packets from the Government of India service outlets was carried out in Delhi during July to August, 1992. One centre from each of the municipal zones of Delhi was selected randomly. Four hundred mothers with a child having diarrhoea reporting to the nearest centre were studied using a standardized questionnaire adopted from the WHO household survey schedule. Two paramedical personnel from each of the centres who were responsible for distribution of ORS were also interviewed regarding their knowledge of preparation of ORS. Results indicate that only 10.8% of mothers prepared the ORS correctly and that the majority (83%) of the paramedicals involved in ORS distribution had correct knowledge about its preparation. Communication methods directed at the mothers regarding the preparation of ORS should be stepped up in these communities.

Child, Preschool↗
PubMed1992

Studies on human lenses: II. Distribution and solubility of fluorescent pigments in cataractous and non-cataractous lenses of Indian origin.

Fluorometric studies of cataractous and non-cataractous human lenses were carried out to study the emission characteristics and the distribution and solubility of lenticular pigments. Most of the detected fluorophores were well distributed over the cortical and nuclear portion of the lens. The decrease in solubility of proteins with aging and cataract formation is concomitant with increasing photolysis of tryptophan. However, this is likely a phenomenon independent of the photochemical transformations of the lens proteins. The number of emitting species in the diseased lenses are higher than in the normal mature lenses. A species emitting around 375 or 388 nm is of particular interest (lambda cx 330 nm) in that the emission characteristics of this fluorophore resemble kynurenic acid which has a high photosensitizing efficiency. The concentration of fluorescent pigments in the lenses of Indian origin is significantly high. The intense pigmentation could be attributed largely to the formation of photoproducts in the absence of normal endogenous antioxidant accumulation that is dependent on nutrition standard. If, indeed, any of these fluorescent pigments, because of their photosensitizing ability, are responsible for lenticular opacity, it is not the abundance of sunlight alone but also malnutrition that could account for the high incidence of cataract in India.

Adult↗
PubMed1992

Eating epilepsy: a study of twenty cases.

Twenty cases of eating epilepsy have been studied over a period of 5 years (1985-1989). Males outnumbered females (4:1). Heavy meal comprising conventional Indian diet (viz, rice, vegetables, etc), was found to be the most important provocating factor (14 out of 20 cases). The attacks occurred at lunch time in most cases (15). Thirteen cases had generalised seizures. Electro-encephalogram showed focal changes in 10 cases, generalised changes in 6 cases, while 4 cases had normal electro-encephalogram. Computerised tomography scan was normal in all the cases (7) when it was done.

Adolescent↗
PubMed1991

17beta-Estradiol releases thyroxine from the thyroid follicles of a teleost, Channa gachua (Ham.).

To observe a direct effect of 17beta-estradiol (E2) on thyroid activity, thyroid follicles were isolated from hypobranchial muscles of a freshwater murrel, Channa gachua. Thyroid follicles were incubated (5 X 10(6) follicles/well) in vitro at 30 degrees for 2 hr without hormone and then 3 hr with E2 or bovine thyroid-stimulating hormone (bTSH). Addition of 10 and 100 ng of E2 to thyroid follicles resulted in 2- and 3-fold increases in thyroxine (T4) release. When 100 ng of bTSH was added to check the isolated follicular function, it stimulated T4 release to more than 3-fold. Increasing doses of E2 from 1 to 100 ng caused a dose-dependent stimulation of T4 release, while a 1000-ng dose reduced T4 release compared to 100 ng. When thyroid follicles of this experiment were lysed by sonication and T4 content was determined, it corroborated the profile of T4 release in response to varied E2 doses. E2 was ineffective in increasing 125I uptake by the follicles, while bTSH elevated it by 45% over the control. Incubation of varied concentrations of [3H]estradiol with cytosol and nuclear fractions of thyroid follicles in the presence of a 100-fold excess of diethylstilbestrol showed saturable specific binding of E2.

Animals↗
PubMed1991

Evaluation of amiodarone free radical toxicity in rat hepatocytes.

The possible roles of free radicals and lipid peroxidation in the mechanism of toxicity of amiodarone (AD) [2-butyl-3-(3',5'-diiodo-4' alpha-diethylaminoethoxybenzoyl)benzofuran] and its principle metabolite, desethylamiodarone (DE), were examined in primary cultured Sprague-Dawley male rat hepatocytes. AD (20 and 40 micrograms/ml) and DE (10 and 25 micrograms/ml) killed hepatocytes in concentration- and time-dependent fashions. Several antioxidants [Cu,Zn-superoxide dismutase (200 U/ml), catalase (200 U/ml), N,N'-diphenylphenylenediamine (DPPD; 25 microM), butylated hydroxytoluene (0.1 mM), and N-acetylcysteine (5 mM)] were incapable of preventing AD and DE hepatocyte toxicity. Only vitamin E (VE, d,l-alpha-tocopherol acetate; 20-200 microM) prevented AD and DE toxicity. No correlation between the onset of hepatocyte death by AD and DE and hepatocyte lipid peroxidation was seen. Both drugs inhibited NADPH-dependent rat liver microsomal superoxide production. These results, excluding the preventive effects of VE, do not support a free radical/lipid peroxidation mechanism of hepatocyte toxicity by AD and DE. VE may have prevented hepatocyte toxicity through non-antioxidant effects.

Acetylcysteine↗
PubMed1991

In vitro infection of natural killer cells with different human immunodeficiency virus type 1 isolates.

Natural killer (NK) cells are a discrete subset of leukocytes, distinct from T and B lymphocytes. NK cells mediate spontaneous non-MHC-restricted killing of a wide variety of target cells without prior sensitization and appear to be involved in initial protection against certain viral infections. Depressed NK cell-mediated cytotoxicity, one of the many immunological defects observed in AIDS patients, may contribute to secondary virus infections. Here we report that clonal and purified polyclonal populations of NK cells, which expressed neither surface CD4 nor CD4 mRNA, were susceptible to infection with various isolates of human immunodeficiency virus type 1 (HIV-1). Viral replication was demonstrated by detection of p24 antigen intracellularly and in culture supernatants, by the presence of HIV DNA within infected cells, and by the ability of supernatants derived from HIV-infected NK cells to infect peripheral blood mononuclear cells or CD4+ cell lines. Infection of NK cells was not blocked by anti-CD4 or anti-Fc gamma RIII monoclonal antibodies. NK cells from HIV-infected and uninfected cultures were similar in their ability to lyse three different target cells. Considerable numbers of cells died in HIV-infected NK cell cultures. These results suggest that loss of NK cells in AIDS patients is a direct effect of HIV infection but that reduced NK cell function involves another mechanism. The possibility that NK cells serve as a potential reservoir for HIV-1 must be considered.

Acquired Immunodeficiency Syndrome↗