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Biomedical subjects

P Gupta

Publications and source records attributed to P Gupta.

At least 343 records · Page 19Linked to original sources
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

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

Transcriptional control of the bovine leukemia virus genome: role and characterization of a non-immunoglobulin plasma protein from bovine leukemia virus-infected cattle.

Using cloned bovine leukemia virus (BLV) DNA as a probe in the dot blot hybridization technique, we demonstrated that the expression of the BLV genome in infected lymphocytes is blocked in vivo at the transcriptional level. This blocking effect is due to a non-immunoglobulin protein present in the plasma but not in the serum of BLV-infected cattle. The plasma BLV-blocking protein also blocks the expression of the BLV genome in fibroblast cells of bovine and nonbovine origin infected with BLV in vitro. The plasma BLV-blocking factor has no inhibitory effect on the expression of Rauscher murine leukemia virus and feline leukemia virus in monolayer culture. The plasma BLV-blocking factor is not an interferon molecule. As determined by gel filtration chromatography, the plasma BLV-blocking factor has an apparent molecular weight of ca. 150,000.

Animals↗
PubMed1983

Measurement of the dissociation constant of MgATP at physiological nucleotide levels by a combination of 31P NMR and optical absorbance spectroscopy.

To resolve a controversy in the literature concerning the affinity of Mg++ for ATP to be used in our noninvasive 31P NMR procedure for the determination of free Mg++ in living cells, we have reinvestigated the apparent dissociation constant of MgATP under physiologic ionic conditions and over the cellular range of ATP concentrations by a combination of NMR and optical absorbance techniques. The new combination method utilizes 31P NMR chemical shifts to determine the degree of Mg++ chelation of ATP in a solution containing free ATP and MgATP, and uses a properly calibrated indicator dye, antipyrylazo III, for optical measurement of free Mg++ in the same solution. The data yield an average value of 50 +/- 10 microM for the apparent dissociation constant of MgATP which indicates low levels of free Mg++ (less than 1 mM) in several different types of tissues, including perfused heart muscle, contrary to a recent report in the literature.

Adenosine Triphosphate↗
PubMed1983

Localization of urinary lactosylceramide in cytoplasmic vesicles of renal tubular cells in homozygous familial hypercholesterolemia.

An average 15-fold increase in lactosylceramide (LacCer) in the sediment of receptor-negative, familial hypercholesterolemic (FH) homozygotes has been reported [Chatterjee, S., Sekerke, C.S. & Kwiterovich, P.O., Jr. (1982) J. Lipid Res. 23, 513-522]. We report here the abnormal urinary excretion of significant numbers of renal tubular cells in eight FH homozygotes. The mean activity of gamma-glutamyltransferase, a marker for renal tubular cells, was twice as high in urinary sediment of FH homozygotes as in normals. Membrane-enclosed cytoplasmic vesicles that stained strongly positive with a fluorescein-labeled antibody against LacCer were found in the renal tubular cells of all homozygotes except two who had undergone a portacaval shunt. These two had normal urinary levels of LacCer, and the cytoplasmic vesicles were vacuolated. In the other six, most of the fluorescent antibody label was intracellular and perinuclear. The cytoplasmic vesicles stained strongly with polychromatic Papanicolaou stain, periodic acid/Schiff reagent, and oil red O. Electron microscopy revealed perinuclear membrane-enclosed lipid and free lipid droplets. When two FH homozygotes, who excreted increased LacCer, underwent plasma exchange, the cytoplasmic vesicles became empty, and the urinary LacCer level decreased into the normal range. We conclude that the increased urinary excretion of LacCer in FH homozygotes occurs in renal tubular cells and that the intracellular locatin of LacCer is within cytoplasmic vesicles. The presence of LacCer within these vesicles can be modulated by treatment with plasma exchange.

Adolescent↗
PubMed1983

On the noninvasive measurement of intracellular free magnesium by 31P NMR spectroscopy.

We previously introduced a noninvasive measurement of the concentration of free Mg2+ in intact cells and tissues using 31P NMR. To resolve a controversy in the literature concerning the affinity of Mg2+ for ATP used in our procedure, the apparent dissociation constant of MgATP under simulated intracellular conditions has been determined by three independent magnetic resonance methods, including a newly developed combination procedure for determining this value at intracellular ATP levels. The new combination method, which utilizes 31P NMR to determine the degree of Mg2+ chelation of ATP and the dye antipyrylazo III for optical determination of free Mg2+, yielded a value of (50 +/- 10) microM for this apparent dissociation constant at pH 7.2 in the presence of 0.15 M K+ and 25 degrees C. We further show that hydroxyquinolines are not satisfactory indicators for optical determination of the Mg2+-nucleotide dissociation constant. From our determinations a low value of free Mg2+ (less than 1 mM) is established for all of the tissues studied, including perfused heart muscle, contrary to a recent report in the literature. Saturating human erythrocytes with Mg2+ results in an alpha- and beta-phosphorus resonance separation for intracellular ATP that is indistinguishable from that observed in a noncellular MgATP control under similar conditions, showing that MgATP resonances in this cell are unaffected by the cellular environment.

Adenosine Triphosphate↗
PubMed1982

Expression of bovine leukemia virus genome is blocked by a nonimmunoglobulin protein in plasma from infected cattle.

Plasma of cattle infected with bovine leukemia virus contains a soluble factor that blocks the expression of the viral genome in cultured lymphocytes. The blocking factor is not present in plasma of bovine leukemia virus-free cattle or of cattle infected with common bovine viruses. Blocking of bovine leukemia virus expression by the plasma factor is reversible, and seems to be mediated by a nonimmunoglobulin protein molecule.

Animals↗
PubMed1982

Differential sensitivity of muntjac lymphocyte chromosomes to mitomycin C, bromodeoxyuridine and hydroxylamine at different cell-cycle stages.

Quantitative and qualitative analyses were made of aberrations induced by 3 hitherto well-known mutagens, mitomycin C (MC), 5-bromodeoxyuridine (BUdR and hydroxylamine hydrochloride (HA), in muntjac chromosomes, during different stages of the cell cycle. The sensitivity to MC was increased in G1, reached its maximum in early S and was considerably decreased in late S and G2 stage treated cells. BUdR induced maximal aberrations when given during the synthetic phase and the cells in G1 and G2 were least affected. The sensitivity of the cells to HA in terms of induced chromosomal aberrations increased as they moved through the cell cycle, i.e. more damage was observed in cells treated in late S and G2 stage than in those treated at G1 and early S stages. While there were defined patterns of cell-cycle stage-dependent sensitivity for all 3 chemicals, the chromosomal sites being preferentially affected by each were found to be specific and invariant at different stages. Thus, it is presumed that the functional state of such "preferred sites" at one or other stage of the cell cycle is the factor responsible for the stage-dependent sensitivity of a cell towards these chemicals.

Animals↗
PubMed1982

Localization of the casein gene family to a single mouse chromosome.

A series of mouse-hamster somatic cell hybrids containing a variable number of mouse chromosomes and a constant set of hamster chromosomes have been used to determine the chromosomal location of a family of hormone-inducible genes, the murine caseins. Recombinant mouse cDNA clones encoding the alpha-, beta-, and gamma-caseins were constructed and used in DNA restriction mapping experiments. All three casein cDNAs hybridized to the same set of somatic cell hybrid DNAs isolated from cells containing mouse chromosome 5, while negative hybridization was observed to ten other hybrid DNAs isolated from cells lacking chromosome 5. A fourth cDNA clone, designated pCM delta 40, which hybridized to an abundant 790 nucleotide poly(A)RNA isolated from 6-d lactating mouse mammary tissue, was also mapped to chromosome 5. The chromosomal assignment of the casein gene family was confirmed using a mouse albumin clone. The albumin gene had been previously localized to mouse chromosome 5 by both breeding studies and analogous molecular hybridization experiments. An additional control experiment demonstrated that another hormone-inducible gene, specifying a 620 nucleotide abundant mammary gland mRNA, hybridized to DNA isolated from a different somatic cell hybrid line. These studies represent the first localization of a peptide and steroid hormone-responsive gene family to a single mouse chromosome.

Animals↗
PubMed1982

Evaluation of ribavirin in the treatment of acute hepatitis.

In this double-blind, placebo-controlled study, treatment of 60 acute hepatitis patients with ribavirin resulted in a more rapid reduction of abnormal laboratory values when compared with the placebo group. Moreover, improved clinical status as reflected by increased appetite with resultant weight gain was noted to be significantly greater in the ribavirin-treated patients. Ribavirin was well tolerated. With this dosage regimen, there were no side effects or changes in laboratory values that could be associated with drug-related toxicity. Since hepatitis A is one of the most common viral infections afflicting the Indian population, the use of a safe and effective therapeutic agent, such as ribavirin, will be necessary to treat these cases.

Adolescent↗