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Biomedical subjects

C Gupta

Publications and source records attributed to C Gupta.

34 records · Page 2Linked to original sources
PubMed1985

Long-term marrow culture of cells from patients with acute myelogenous leukemia. Selection in favor of normal phenotypes in some but not all cases.

Long-term cultures were initiated with leukemic marrow aspirate cells from each of 13 newly diagnosed acute myelogenous leukemia (AML) patients. Initial assessment of the clonogenic potential of the marrow suggested that normal hemopoietic progenitors were reduced in most cases and progenitors of abnormal colonies and clusters were present in 10 cases. Subsequent assays of both nonadherent and adherent fractions of long-term cultures revealed two patterns of progenitor cell behavior. The most common pattern (nine cases) featured the detection after 1-4 wk of near normal numbers of typical erythroid, granulopoietic, and mixed colony-forming progenitor cells. Progenitors of abnormal (blast) colonies and clusters initially demonstrable in eight of these nine cases were, in these cases, not sustained in long-term culture and could not be found after 4 wk. Conversion to cytogenetic normalcy in long-term culture was confirmed in two experiments in this group. The second pattern (four cases) was characterized by the failure of progenitors capable of normal differentiation to become detectable in long-term cultures, and the concomitant maintenance of blast progenitors in the two cases in this group where such cells were initially demonstrable. Although progenitors capable of producing abnormal (blast) colonies or clusters in methylcellulose were not detected in either of the other two experiments, the maintenance for 6 wk of a hypercellular nonadherent blast population in one of these suggested the persisting activity of an "adherent layer-dependent" leukemic progenitor cell. Taken together, these findings indicate a strong correlation between the presence of leukemic blasts and their progenitors and a decreased level of normal hemopoiesis. In addition, the failure of leukemic cells to be maintained in long-term marrow cultures from some (but not all) AML patients suggests new applications of this methodology for studies of early stages of leukemic cell development.

Adult↗
PubMed1985

Dexamethasone-induced phospholipase A2-inhibitory proteins (PLIP) influenced by the H-2 histocompatibility region.

Recent work has indicated that the H-2 histocompatibility complex on chromosome 17 influences the degree of glucocorticoid-induced teratogenicity and anti-inflammatory response. Since both of these hormonal actions appear to be mediated by the induction of phospholipase A2-inhibitory proteins (PLIP), the influence of the H-2 complex on the induction of PLIP by glucocorticoids in thymocytes and embryonic palates has been investigated. Analysis of dexamethasone-induced PLIP by Sephadex G-100 revealed four peaks of mol wt 55,000, 40,000, 28,000 and 15,000 in mouse thymocytes and from one to three of these PLIPs in mouse embryonic palates. The 55,000 mol wt PLIP comprised 50-60% of the total activity. The total amount of dexamethasone-induced PLIP is significantly higher in B10.A (H-2a) thymocytes than that in thymocytes of their congenic resistant partners, B10 (H-2b). The induced level of PLIP in the embryonic palates treated with dexamethasone is also significantly higher in the H-2a congenic strains with either the A or B background (AWy or B10.A) than that in their resistant partners (A.BY or B10). Thus, both susceptibility to glucocorticoid-induced cleft palate and the production of PLIP by this hormone are influenced by the H-2 complex.

Animals↗
PubMed1985

H-2 histocompatibility region influences the inhibition of arachidonic acid cascade by dexamethasone and phenytoin in mouse embryonic palates.

We have reported that susceptibility to glucocorticoid- and phenytoin-induced cleft palate and glucocorticoid receptor levels in mice are influenced by the H-2 histocompatibility complex on chromosome 17. Phenytoin competes with glucocorticoids for the glucocorticoid receptor and inhibits production of prostaglandins and thromboxanes. In this paper, we have investigated whether glucocorticoids and phenytoin inhibit arachidonic acid release and prostaglandin biosynthesis directly in the embryonic palates and whether the H-2 gene complex influences the degree of inhibition. Using congenic strains varying only in the H-2 region, we demonstrate here that both glucocorticoids and phenytoin inhibit the release of 3H-arachidonic acid and prostaglandin biosynthesis from embryonic palatal tissue, prelabeled with 3H-arachidonic acid. The degree of inhibition of arachidonic acid release and of prostaglandin biosynthesis is greater in the strain with H-2a (A/Wy) than in its corresponding congenic partner H-2b (A.BY). Thus, these results provide further evidence for a similar genetic and biochemical pathway for the teratogenic action of both phenytoin and glucocorticoids.

Abnormalities, Drug-Induced↗
PubMed1979

In vivo metabolism of progestins. V. The effect of protocol design on the estimated metabolic clearance rate and volume of distribution of medroxyprogesterone acetate in women.

The metabolism of the synthetic progestin, [3H]medroxyprogesterone acetate (MPA), was studied in women using a single injection technique. Computer-implemented analysis was used to calculate the MCR (MCRMPA) and volume of distribution (VoMPA) from the steroid disappearance curve. The value of an objective curve-fitting technique was demonstrated. The effect of protocol design (number and frequency of samples) on these metabolic parameters was evaluated. The estimation of VoMPA was most sensitive to alterations of experimental design and biological variability, while MCR was less easily effected. The MCRMPA of 1668 +/- 146 (SEM) liters/day was lower than that for progesterone but higher than that of another synthetic steroid, dexamethasone. Treatment of women with MPA or aminoglutethimide, two drugs known to increase the rates of testosterone and dexamethasone metabolism, respectively, did not alter MCRMPA. From these observations we conclude 1) with the single injection technique it is difficult to estimate Vo of compounds such as MPA which are rapidly metabolized and 2) the MCRMPA was higher than expected and less susceptible to drug-induced changes than the clearance of other steroids.

Aminoglutethimide↗
PubMed1978

Androgenic effects of the antiprogestagen RMI 12,936.

RMI 12,936 (7alpha-methyl-17beta-hydroxy-androst-5-en-one) was tested for androgenic activity in mouse kidney and for antiprogestational activity in guinea-pig uterus. RMI 12,936 stimulated an increase in kidney weight and in the activity of the androgen-responsive renal enzymes, beta-glucuronidase, alcohol dehydrogenase and arginase. RMI 12,936 was bound by the renal androgen receptor with a relative affinity approximately one-third that of testosterone. Although RMI 12,936 did not stimulate glycogen accumulation in guinea-pig endometrium in vivo, it was active in endometrial organ culture. When RMI 12,936 was combined with progesterone, glycogen accumulation in vitro was partly inhibited. RMI 12,936 was bound by the guinea-pig uterine progesterone receptor with a relative affinity of less than 1%. It is concluded that RMI 12,936 is an androgenic steroid with antifertility actions and in-vitro antiglycogenic activity.

Androstenols↗
PubMed1977

The in vivo metabolism of progestins. IV. The metabolic clearance rate and plasma binding of 6alpha-methylpregn-4-ene-3, 20-dione in women.

[3H]6alpha-methylprogesterone (6MP) was synthesized by selective catalytic tritiation of the delta1-olefinic bond of 6alpha-methylpregna-1,4-diene-3,20-dione. The metabolic clearance rate of 6MP (MCR6MP) was determined in 6 women by the single injection technique. The plasma MCR6MP was 4047 +/- 298 L/day (59 +/- 15 L/day/kg) which was higher than the MCR of progesterone and medroxyprogesterone acetate (6alpha-methyl-17alpha-hydroxy-pregna-4-ene-3,20-dione acetate). The high clearance was not due to binding or metabolism of 6MP by red cells. Although 6MP was bound to CBG with a lower affinity than progesterone, this could not entirely explain the high MCR6MP. When considered with the reports of progesterone and medroxyprogesterone acetate clearance, the present studies suggest that the 6alpha-substitution of progesterone leads to an increased rate of steroid metabolism in women.

Carrier Proteins↗
PubMed1976

Testosterone-binding protein in reproductive tracts of fetal rats.

Testosterone-binding proteins may mediate the induction of Wolffian duct differentiation by testicular testosterone. The presence of such protein(s) was sought in reproductive tracts of 14.5-21.5-day-old fetal rats. Supernatant fractions (127,000 x g) were equilibrated with [3H]T) +/- radioinert testosterone in Tris - HCl:EDTA buffer, pH 7.4, (approximately 0.1 mg protein/0.5 ml) at 4 C for 16 hours. Bound and free (3H)T were separated by charcoaldextran adsorption or Sephadex G-100 gel filtration. The results with 14.5-15.0-day-old tracts were: a) specific binding to protein was saturated with increasing (3H)T concentration; b) Scatchard plot analysis indicated the presence of a single class of binding sites with high affinity (apparent Kd = 2 nM) and limited capacity (approximately 16 fmol/mg protein) for (3H)T; c) specific uptake was limited to (3H)T and (3H)5 alpha-dihydrotestosterone; d) (3H)T uptake by the tract supernatant was tissue-specific; e) pronase treatment abolished binding capacity for (3H)T; f) bound radioactivity consisted solely of (3H)T; and g) the mesonephric and ductal segment of the genital tract specifically binds (3H)T. The data demonstrate binding protein(s), specific for testosterone and possibly dihydrotestosterone, in the genital ducts of 14.5-15-day-old fetal rats. (3H)T binding to genital duct supernatants from male but not from female fetuses increased about 5-fold between 14.5 and 20.5 days of gestation. Upon Sephadex G-100 gel filtration, radioactivity was confined to the macromolecular fraction appearing in the void volume. Nuclear fractions, obtained from intact ducts incubated with (3H)T at 30 C but not at 0 C contained radioactivity. These observations are compatible with the existence of a cytoplasmic testosterone receptor or carrier protein aggregate. We have thus concluded that testosterone-binding proteins are present in the genital ducts of rat fetuses and that, in the male, their concentrations increase with progressive Wolffian duct differentiation.

Animals↗
PubMedDate not supplied

Estrogen receptor levels in a murine model of systemic lupus erythematosus.

Offspring of a cross between the NZB and NZW mice (F1) develop a disease similar to SLE in humans. Female mice of the F1 strain develop the disease at a younger age and die earlier than the males. In order to test the hypothesis that estrogen receptor concentrations in the lymphoid organs of these mice may correlate with increased female susceptibility, estrogen receptor assays were performed on cytosol from the uterus, thymus, spleen, and liver of affected animals and the parental stock using the dextran-charcoal method. Specific binding of the receptor was analysed by Scatchard analysis. There were no differences among receptor concentrations in the uterus, thymus, and spleen of NZB, NZW, and F1 mice. However, the estrogen receptor concentrations in the liver from NZW and F1 mice were twice that of NZB mice. This observation may be of importance since the liver is involved in steroid metabolism and abnormalities of estrogen metabolism have been reported in human SLE.

Animals↗