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Biomedical subjects

S Chatterjee

Publications and source records attributed to S Chatterjee.

At least 433 records · Page 24Linked to original sources
PubMed1985

A rapid screening procedure for the isolation of nonconditional replication mutants of Mason-Pfizer monkey virus: identification of a mutant defective in pol.

A rapid, sensitive, and reproducible method for the isolation of human cell clones containing nonconditional, replication-defective (rd) mutants of Mason-Pfizer monkey virus (M-PMV), the prototype of the D-type retroviruses is described. The two mutants, rd1 and rd2, thus far isolated have been analyzed for virus particle production (using radiolabeled precursors and by electron microscopy) and for the status of intracellular viral precursors. Thin sections of rd1 and rd2 infected cells showed typical M-PMV particles when observed under electron microscope. A more direct assay of virus production, by labeling the mutant cell clones with [3H]uridine, also showed a distinct virus peak at an approximate density of 1.16 g/ml when culture fluids from rd1 and rd2 were analyzed. Analyses of these two mutants showed no defect in either gag or env gene products, however, further analysis of rd1 showed that the Pr180gag-pol was altered in its migration on SDS-polyacrylamide gel electrophoresis and no reverse transcriptase activity could be detected in rd1 virions. Mutant rd2, on the other hand, assembles noninfectious virus particles that are otherwise indistinguishable from those produced by wild-type cell clones. The biochemical basis for the defect in this mutant remains to be established.

Defective Viruses↗
PubMed1985

Effect of cloned human interferons on protein synthesis and morphogenesis of herpes simplex virus.

Pretreatment of human fibroblast cells with 100 U of either cloned human alpha-2 or beta interferon per ml for 24 h reduced the release of infectious herpes simplex virus type 1 by more than 99%. This inhibition in infectivity correlated well with the total number of extracellular virus particles released from treated cells as determined by DNA dot blot hybridization analysis. Electron microscopic observations of interferon-treated human fibroblast cells clearly demonstrated typical assembly of nucleocapsids inside the nucleus, even though very few mature extracellular particles were seen. Analysis of virus-specific proteins by the immunoblot technique showed that neither species of interferon had a significant inhibitory effect on the synthesis of major nucleocapsid proteins. However, the synthesis of specific glycoproteins (D and B) was drastically reduced or delayed in beta-interferon-treated cells. The results presented in this communication suggest that cloned human interferons block herpes simplex virus morphogenesis at a late stage and inhibit the release of particles from the treated cells.

Animals↗
PubMed1985

Symmetrical and asymmetrical sexual isolation among laboratory strains of Drosophila ananassae.

Male-choice experiments using five isofemale lines of Drosophila ananassae originating from different localities were performed to study sexual isolation within the species. In most of the crosses homogamic matings outnumber heterogamic ones, and deviation from randomness is statistically significant in 11 of 20 crosses. This provides evidence for positive assortative mating within D. ananassae. Isolation indices range from -0.057 to 0.555. Eleven positive isolation indices are significantly greater than zero. Both types of sexual isolation, symmetrical and asymmetrical, have been observed among different strains. Thus the present results clearly indicate that the laboratory strains of D. ananassae have developed behavioural reproductive isolation as a result of genetic divergence.

Animals↗
PubMed1985

Sarcoidosis in India.

Sarcoidosis in India frequently presents in elderly males with a dissociation between extensive radiological changes and scanty clinical signs in the chest. Clubbing is not infrequent. Erythema nodosum, generalized lymphadenopathy, eye changes, and bone cysts are uncommon. Spontaneous resolution or asymptomatic course is very rare. Follow-up reports, whenever available, show that patients have frequent relapses which respond well to short courses of steroids. This comparative study shows a few differences between this series (of 90 cases diagnosed from 1957 to 1982), two different Western series and the World series. Detection and documentation of cases of sarcoidosis in India have been on the increase during the last few decades. Whether that is due to increase in incidence or awareness is difficult to say. In two special centres in India, the frequency of detection of the disorder varied between 61.2 (in a chest hospital in Delhi during 1957-74) to over 150 per 100 000 patients (Calcutta) attending a general hospital with a sarcoidosis clinic (1980-82).

Adolescent↗
PubMed1984

UV non-mutable mutant from V-79 Chinese hamster cells.

To get an idea about the response of a living system, exposed to gradually increasing doses of a mutagen for several generations, a population of V-79 Chinese hamster cells was exposed repeatedly to gradually increasing doses of UV radiation. Each dose was followed by a variable period of growth for at least ten generations. After treatment the cells were not mutable by UV radiation, though MNNG was capable of producing mutations with the same efficiency as in the untreated cells. In terms of viability, the treated cells behaved exactly as the untreated ones for both UV and MNNG. The observed behaviour of the treated cells was found to be stable for during the 50 passages studied.

Animals↗
PubMed1984

Distribution of antithrombin III and glucosylceramide in human plasma lipoproteins and lipoprotein deficient plasma.

We have investigated the distribution of antithrombin-III and glucosylceramide (Glc-Cer) in human plasma, plasma lipoproteins and lipoprotein-deficient plasma. Antithrombin III activity was measured employing immunochemical and biological assays. Glc-Cer was quantified by gas liquid chromatography (GLC). Whole plasma contained 145 micrograms antithrombin III/ml plasma, all of which was associated with the lipoprotein-deficient plasma (d greater than 1.25 g/ml). Whereas, most if not all the plasma GlcCer was associated with plasma low density lipoproteins (LDL) (d-1.022-1.055 g/ml) and high density lipoproteins (HDL) (d-1.063-1.25). GlcCer was not found in the lipoprotein-deficient plasma. We conclude that GlcCer on lipoproteins does not contribute to antithrombin III activity. Moreover, the absence of GlcCer in lipoprotein-deficient plasma does not impair antithrombin-III activity.

Antithrombin III↗
PubMed1984

Separation of human urinary proximal tubular cells from familial hypercholesterolemic homozygotes by Ficoll gradient centrifugation. Morphological and biochemical characteristics.

The isolation of renal proximal tubular (PT) cells from the fresh urinary sediment ( UrS ) of familial hypercholesterolemic (FH) homozygotes using discontinuous Ficoll gradient centrifugation was studied. For comparative purposes, cultured cells derived from normal human UrS or kidney were also studied. Unfractionated PT cells were nucleated and 90-99% of the cells excluded trypan blue. Both the unfractionated and fractionated cultured normal PT cells contained numerous empty cytoplasmic vesicles. In contrast, similar preparations from the UrS of FH homozygotes contained membrane-enclosed cytoplasmic vesicles that stained with the Papanicolaou (Pap) reagent and were strongly positive with a fluorescein-labeled antibody against lactosylceramide. The PT cells of FH homozygotes contained 2.0 to 2.5 fold higher activity of gamma-glutamyltransferase and alkaline phosphatase, respectively, than the unfractionated UrS cells. We conclude that human PT cells can be separated from other UrS cells by ficoll gradient centrifugation, and that most, if not all of the LacCer present in the UrS of FH homozygotes is associated with the PT cells. Purified PT cells should provide a useful model to test the biochemical mechanisms of LacCer accumulation in FH.

Adolescent↗
PubMed1984

Effect of cloned human interferons on the replication of and cell fusion induced by herpes simplex virus.

Human alpha- and beta-interferons, expressed from cloned genes, block the replication of, and cell fusion induced by herpes simplex viruses. This inhibition is neutralized by antiserum to interferon and demonstrates species specificity. The block in replication appears to be late in the replication cycle of herpes simplex virus, since similar levels of viral DNA are synthesized in both interferon-treated and untreated cells.

Cell Fusion↗
PubMed1984

Detoxication of industrial pollutants by the glutathione glutathione-S-transferase system in the liver of Anabas testudineus (Bloch).

The interrelationship of reduced glutathione (GSH) and glutathione-S-transferase in the liver of a freshwater climbing perch Anabas testudineus (Bloch) exposed to common industrial pollutants has been studied. In both short- and long-term treatments there was a concomitant decrease in reduced glutathione profile and an increase in glutathione-S-transferase activity. It may be surmised that the majority of xenobiotics of industrial origin are detoxicated by the glutathione glutathione-S-transferase pathways enabling the fish to survive exposure to the additive and/or synergistic toxicity of mixtures of poisons.

Ammonia↗
PubMed1984

Immunohistochemical localization of glycosphingolipid in urinary renal tubular cells in Fabry's disease.

Although the accumulation of neutral glycosphingolipid (GSL), principally globotriaosylceramide ( GbOse3Cer ), in the kidney of patients with Fabry's disease is well documented, little is known about the type and quantity of lipid present in the renal tubular cells shed in the urine. Using a variety of cytologic technics, the authors examined exfoliated cells found in the urine specimens of patients hemizygous and heterozygous for alpha-galactosidase A deficiency. Renal tubular cells contained periodic acid- Shiff positive material that could be identified easily by Papanicolaou stain. A fluorescein-labeled antibody specific for GbOse3Cer localized this lipid to the cytoplasm. Electron microscopy showed numerous electron-dense multilamellar membranous inclusions within phagolysosomes and electronlucent material within lysosomes of tubular cells. Based on immunofluorescence, heterozygote individuals had similar distribution but less quantity of cytoplasmic GSL. The authors conclude that in Fabry's disease GSL accumulates probably in lysosomes of renal tubular cells. These cells are exfoliated and can be identified specifically in voided urine specimens. Examination of renal tubular cells in urine using the fluorescein antibody technic described here affords a noninvasive means of diagnosing and following the effect of therapy in patients with Fabry's disease.

Adolescent↗
PubMed1984

Glycosphingolipids and plasma lipoproteins: a review.

Glycosphingolipids (GSL) are complex, sugar-containing lipids that are transported in plasma on lipoproteins, particularly low density (beta) lipoproteins (LDL). LDL are taken up and metabolized by cells through a LDL receptor-mediated pathway. Cells from receptor-negative familial hypercholesterolemic (FH) homozygotes lack a functional LDL receptor and the cellular uptake of LDL occurs through a LDL receptor-independent pathway. We have studied the relation between LDL and GSL metabolism using an in vitro model of cultured human fibroblasts and an in vivo model of renal tubular cells shed in the urine. Using biochemical, morphological, and immunocytological techniques, we have demonstrated that LDL taken up through the LDL receptor-independent pathway results in the accumulation of GSL in cells in vitro and in vivo. The storage of GSL is localized to intracytoplasmic vesicles and such storage can be modulated by changing the concentration of LDL in the culture medium or in plasma. The possible effect of LDL on certain steps in the intracellular metabolism of GSL in normal and receptor-negative-homozygous FH cells is reviewed.

Cells, Cultured↗
PubMed1984

A cell-cycle-phase-specific mutant of amoeba.

The treatment of Amoeba indica with ethylmethanesulphonate (EMS) at early S, late S and late G2 phases of the cell cycle leads to the production of mini amoeba cells in the G2 period. Among them, only a few of the mini cells that originated from EMS treatment at early S phase have been found to be viable and to give rise to stable clones. These mini amoebae show stable and altered characteristic features in cell size, structure, membrane properties, cell-cycle timing and the patterns of macromolecular syntheses as compared to the parental cells. It is suggested that the mini amoeba cell is a size mutant that has a cell-cycle-phase-specific origin. The finding is discussed in relation to preferential mutagenic action involving the functional state of DNA leading to the production of viable mutant amoebae.

Amoeba↗