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Biomedical subjects

D Ghosh

Publications and source records attributed to D Ghosh.

At least 181 records · Page 10Linked to original sources
PubMed1993

Subcellular action of estradiol-17 beta in a freshwater prawn Macrobrachium rosenbergii.

Injections with different doses (0.1, 0.25, 0.5, 1.0, 2.0, and 4.0 micrograms/g) of estradiol-17 beta (E2), administered three days consecutively, showed a statistically significant increase in mitochondrial Na(+)-K(+)-ATPase, cytosolic malate dehydrogenase, and cytosolic glucose-6-phosphate dehydrogenase activities in a dose-dependent manner in the hepatopancreas of the freshwater prawn (Macrobrachium rosenbergii) on the 4th day of treatment compared to the control values. A lower dose of 0.05 microgram/g was without any effect on these enzyme activities. A uniform increase in the Mg(2+)-ATPase activity was observed after injections with 0.5, 1.0, and 2.0 micrograms/g of E2. Ergosterol, a nonsex steroid did not show any change in the malate dehydrogenase and glucose-6-phosphate dehydrogenase activities on which this compound was tested at a 2.0 micrograms/g dose, compared to the control values. Simultaneous injection of tamoxifen (0.5 microgram/g), an antiestrogenic compound, with E2 (2 micrograms/g) caused inhibition of the E2-induced rise in mitochondrial Na(+)-K(+)-ATPase and cytosolic NADP-linked malate dehydrogenase activities. Conversely, tamoxifen (0.5 and 1.0 microgram/g) behaved as an estrogen agonist to the response (increase) of Mg(2+)-ATPase and cytosolic glucose-6-phosphate dehydrogenase activities. Potentiation of the estrogen effect with tamoxifen (1.0 microgram/g) was observed in these enzyme activities when used simultaneously with E2 (2 micrograms/g). Use of cycloheximide (0.5 mg/liter), a protein synthesis blocker, inhibited the inhibited the E2 (2 micrograms/g)-induced increase in all the enzyme activities studied. The data show specific and prominent subcellular action of estrogen with an indication of its role in energy-dependent ion transport and metabolic activation in hepatopancreas of the freshwater prawn.

Animals↗
PubMed1993

Crystallization and preliminary X-ray diffraction studies of a mammalian steroid dehydrogenase.

20 beta-Hydroxysteroid dehydrogenase from the cytosolic fraction of neonatal pig testis is a NADPH-dependent enzyme that catalyzes the reduction of the C-20 ketone of C21-steroids. It is 85% homologous in amino acid sequence to the human enzyme, carbonyl reductase. The enzyme has been crystallized from 36% saturated ammonium sulfate in 10 mM 2-[N-Morpholino]ethanesulfonic acid buffer. The size and the quality of nicely formed square bi-pyramidal crystals were improved by using a "seeding" technique. The crystals diffract X-rays to at least 2.5 A resolution. The space group is P4(1)2(1)2 (or P4(3)2(1)2) and the unit-cell dimensions are a = b = 58.53 A, c = 165.64 A. There is one molecule (M(r) = 30.5 kDa; 289 amino acid residues) in the asymmetric unit. An intensity data set to 2.5 A has been collected with an overall Rmerge of 6.6% for all reflections.

Animals↗
PubMed1993

Vertebral haemangioma presenting as Kasabach-Merritt syndrome.

A case of spinal cord compression due to vertebral haemangioma is described as presenting as part of the Kasabach-Merritt syndrome, which is characterized by bleeding disorder, thrombocytopenia and leukopenia. A dramatic improvement in neurological status and coagulation profile following surgical decompression and postoperative radiotherapy is reported. A brief review of the literature on the usefulness of radiotherapy is discussed.

Adult↗
PubMed1993

Morphological characteristics of preimplantation stage endometrium in the rhesus monkey.

The morphological characteristics of endometrium on day 6 after ovulation of conception (group 1) and non-fecund, menstrual (group 2) cycles have been studied in the rhesus monkey (n = 30). A conception cycle was distinguished by the presence of a developmentally normal, age-stage-synchronized embryo. Thus, 78% of the mated cycles (n = 18) yielding synchronous embryos (12 zona-encased and two zona-free blastocysts) were used for this study. On day 6 after ovulation, no significant changes in the serum concentrations of oestrogen and progesterone were seen in conception cycles (n = 14) compared with the non-mated, normal ovulatory cycles (n = 12). Morphometric analyses revealed that on day 6 of gestation (n = 8), endometrium differed from the corresponding non-mated luteal phase (n = 7) with significant increases in epithelial mitosis (P < 0.01), height of glandular epithelium (P < 0.05), volume ratio of gland cell to gland (P < 0.03), degree of pseudostratification (P < 0.02), and higher frequency of supranuclear, adluminal accumulation of vacuoles in gland cells (P < 0.05). The degree of stromal oedema was higher (P < 0.02) in fecund cycles but there was no change in venular diameter. In a separate set of experiments, estimates of tissue vascular response revealed a higher (P < 0.02) endometrial extravascular albumin space on the same day of gestation; there were no differences, however, in endometrial blood volume, or in the number of von Willebrand antigen-positive capillaries and small vessels between the two groups (group 1, n = 6; group 2, n = 5).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Anti-nidatory effect of a single, early post-ovulatory administration of mifepristone (RU 486) in the rhesus monkey.

The hypothesis that post-coital administration of mifepristone (RU 486) as a single dose in the early luteal phase can be an effective anti-nidatory strategy was tested using the rhesus monkey as the experimental model. Incidence of pregnancy, vaginal bleeding patterns, profiles of menstrual cyclicity and of serum levels of progesterone and oestrogen were examined following administration of RU 486 as a single dose of 10 mg/kg and 2 mg/kg body weight on the second day after ovulation. In control monkeys (group 1; n = 5) receiving the vehicle alone (benzyl benzoate:olive oil, 1:4, v/v) there was a 60% pregnancy rate. Following s.c. administration of RU 486 at both doses, no pregnancy was recorded in a total of 33 treatment cycles in 12 monkeys. Five monkeys received RU 486 at 10 mg/kg s.c. (group 2) in three consecutive cycles. All animals had complete inhibition of implantation; in addition, the treatment cycle length was prolonged (P < 0.001) due to an extension of the luteal phase. The subsequent follicular phase was unaffected. Mild, premature vaginal bleeding during the luteal phase was recorded in five treatment cycles, 3-5 days after drug application. Though the serum profiles of progesterone and oestrogen in these monkeys showed marked individual variations, there was a characteristic progesterone rebound about 18-20 days after drug administration. Monkeys in group 3 were given RU 486 at 2 mg/kg, s.c. either for three consecutive cycles (group 3a; n = 4) or for two consecutive cycles (group 3b; n = 3). Premature luteal phase vaginal bleeding occurred only in four treatment cycles, within 2-6 days post-treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

N-terminal DNA-binding domains contribute to differential DNA-binding specificities of NF-kappa B p50 and p65.

We previously reported that either oxidation or alkylation of NF-kappa B in vitro abrogates DNA binding. We used this phenomenon to help elucidate structural determinants of NF-kappa B binding. We now demonstrate that Cys-62 of NF-kappa B p50 mediates the redox effect and lies within an N-terminal region required for DNA binding but not for dimerization. Several point mutations in this region confer a transdominant negative binding phenotype to p50. The region is highly conserved in all Rel family proteins, and we have determined that it is also critical for DNA binding of NF-kappa B p65. Replacement of the N-terminal region of p65 with the corresponding region from p50 changes its DNA-binding specificity towards that of p50. These data suggest that the N-terminal regions of p50 and p65 are critical for DNA binding and help determine the DNA-binding specificities of p50 and p65. We have defined within the N-terminal region a sequence motif, R(F/G)(R/K)YXCE, which is present in Rel family proteins and also in zinc finger proteins capable of binding to kappa B sites. The potential significance of this finding is discussed.

Amino Acid Sequence↗
PubMed1993

Hyperkalemic periodic paralysis associated with thyrotoxicosis.

A 32 year old male presented with episodic pure motor weakness for 1 1/2 months. On evaluation he was found to be thyrotoxic. Hyperkalemic challenge test provoked similar weakness with raised serum potassium (6 meq/L). He responded to treatment with neomercazole. Till he became euthyroid, he responded to the addition of acetazolamide to his medication. He is symptom free on antithyroid drug alone over 8 months of follow up.

Acetazolamide↗
PubMed1993

Contranidatory activity of early luteal phase administration of mifepristone in the rhesus monkey.

The contranidatory action of mifepristone (RU 486) given as a single application at different dosages to mated rhesus monkeys (Macaca mulatta) on second day after ovulation has been examined in the present study. In group 1, monkeys (n = 3) received only vehicle (benzyl benzoate: olive oil, 1:4, v/v) and were treated as controls. In group 2 monkeys (n = 4), RU 486 was given by gavage at 10 mg/kg in group 4 (n = 5). The patterns of cycles and profiles of serum estrogen and progesterone were monitored for assessing the occurrence of implantation and pregnancy. At a single dose of 10 mg/kg, RU 486 was found to be ineffective in preventing nidation, resulting pregnancy in three females out of four treated monkeys. Similarly, an s.c. administration of 1 mg/kg could provide pregnancy protection in two of the four treated monkeys. In these monkeys, however, the menstrual cycle characteristics were not affected as compared to pretreatment cycles. Interestingly, the administration of 2 mg/kg, s.c., RU 486 could provide a hundred percent pregnancy protection in mated monkeys, and there was no significant changes in the pattern of menstrual cycle characteristics. It appears that an early post-ovulatory administration of RU 486 may be successfully used in human as an effective once-a-month, early luteal phase contranidatory agent.

Animals↗
PubMed1992

Inhibition of Streptomyces hydrogenans 3 alpha,20 beta-hydroxysteroid dehydrogenase by licorice-derived compounds and crystallization of an enzyme-cofactor-inhibitor complex.

Streptomyces hydrogenans 3 alpha,20 beta-hydroxysteroid dehydrogenase reduces the C20 ketone on glucocorticoids and progestins. We find that two licorice-derived compounds, glycyrrhizic acid and carbenoxolone, inhibit this enzyme with microM Kis. Inhibition is competitive, indicating that these compounds are binding at or close to the catalytic site. Carbenoxolone's high aqueous solubility and affinity for 3 alpha,20 beta-hydroxysteroid dehydrogenase enabled us to prepare crystals of a carbenoxolone-NADH-enzyme ternary complex, which preliminary X-ray analysis indicates has a crystal structure that is significantly different from that of the 3 alpha,20 beta-hydroxysteroid dehydrogenase-NADH complex. A comparison of the tertiary structures of these two complexes should prove useful in understanding this enzyme's catalytic mechanism, as well as those of two homologous enzymes, mammalian 11 beta-hydroxysteroid dehydrogenase and 15-hydroxyprostaglandin dehydrogenase that also are inhibited by carbenoxolone.

Binding Sites↗
PubMed1992

Effect of RU 486 on the endometrial response to deciduogenic stimulus in ovariectomized rhesus monkeys treated with oestrogen and progesterone.

Using the artificial plaque--decidual cell model in rhesus monkeys, the potential role of progesterone in the process of of epithelial and stromal cell responses was investigated by time-adjusted application of an antiprogestin, RU 486. Epithelial plaque formation is an immediate response of the endometrium to either trauma or invading trophoblast cells. To study this process, RU 486 (2.5 mg/kg body weight) or vehicle (ethanol/saline, 7:3, v/v, i.m.) was administered to the first group of monkeys immediately following traumatization (days 16 and 17 of treatment cycle). Histometric analysis revealed that treatment with RU 486 led to significant inhibition (P less than 0.001) in the recruitment of epithelial cells into plaque acini and consequent reduction (P less than 0.001) in the spread of the plaque reaction compared with control monkeys. In the second group of monkeys, experimental treatment was delayed until plaque formation had occurred (days 21 and 22 of cycle). RU 486 induced increased degeneration (P less than 0.01) in plaque cells. Thus the transformation and the maintenance of the epithelial plaque response appears to be progesterone-dependent. Glandular epithelium showed only marginal changes (P less than 0.05) in maximum cell height, amount of pseudostratification and secretory activity of glands as a consequence of RU 486 treatment; however, the antiprogestin induced a higher incidence of glandular apoptosis (P less than 0.01 for both groups). It has been suggested that the higher degree of apoptosis in the glandular epithelium could be a consequence of the progesterone receptor blocking action of RU 486. No distinctive change in endothelial cell ultrastructure was evident following RU 486 treatment; however, venular diameter was significantly increased (P less than 0.01, group I; P less than 0.001, group II) along with an apparent reduction in the extent of oedema. There was increased extravasation (P less than 0.01) and leukocytic infiltration (P less than 0.001, group I; P less than 0.05, group II) following RU 486 treatment. RU 486 induced vascular responses and increased diapedesis could presumably have resulted from its progesterone blocking action in vascular cells. RU 486 accelerated the incidence (P less than 0.01) of stromal decidualization (group I), as well as quantitatively accentuating (P less than 0.001) the decidual cell reaction (group II). It is possible that RU 486 may inhibit specific functions of decidual cells, despite morphologically consistent decidual transformation.

Animals↗
PubMed1992

Glucocorticoid receptor-binding site in the human immunodeficiency virus long terminal repeat.

Previous reports (P. D. Katsanakis, C. E. Sekaris, and D. A. Spandidos, Anticancer Res. 11:381-383, 1991; J. Laurence, M. B. Sellers, and S. K. Sikder, Blood 74:291-297, 1989; R. Miksicek, A. Heber, W. Schmid, U. Danesch, G. Posseckert, M. Beato, and G. Schutz, Cell 46:283-290, 1986) have suggested the existence of a glucocorticoid response element in the long terminal repeat of human immunodeficiency virus (HIV) type 1. This study demonstrated a sequence-specific interaction of the glucocorticoid receptor DNA-binding domain with the previously predicted HIV glucocorticoid response element. This interaction may be relevant to the steroid responsiveness of HIV (P. A. Furth, H. Westphal, and L. Hennighausen, AIDS Res. Hum. Retroviruses 6:553-560, 1990; J. Laurence, M. B. Sellers, and S. K. Sikder, Blood 74:291-297, 1989; J. Laurence, H. Cooke, and S. K. Sikder, Blood 75:696-703, 1990; D. A. Spandidos, V. Zoounpovilis, A. Kotsinas, C. Tsiripotis, and C. E. Sekeris, Anticancer Res. 10:1241-1246, 1990).

Base Sequence↗
PubMed1992

Patterns of ovulation, conception and pre-implantation embryo development during the breeding season in rhesus monkeys kept under semi-natural conditions.

The occurrence of ovulation and conception in the female rhesus monkey (Macaca mulatta) under natural conditions is seasonal and maximum during the months of October to March. Such seasonality in reproduction suggests dependence on environmental factors like photoperiod, temperature and rainfall. There occur significant fluctuations in these environmental factors also during the breeding season itself. Whether there occur any discernible changes in the occurrence of ovulation and conception, and in the incidence of abnormality in pre-implantation stage embryo development in the rhesus monkey, associated with changes in environmental factors within the breeding season has not been known and was investigated in the present study using a total of 304 menstrual cycles over a period of five years. No preferential sidedness for any ovary to ovulate more was evident, the frequency ratio of ovulations in left ovary to right ovary being 1.02. Despite the absence of any pattern in the side selection of ovulations in successive cycles, the chance of ovulations in alternate ovaries for successive cycles appeared more likely (67% cases). An average of 21% of menstrual cycles were found to be non-ovulatory with significantly higher menstrual cycle lengths (p less than 0.03) compared with that of ovulatory cycles. An additional 28% of the mated, conception cycles yielded degenerated or desynchronized pre-implantation stage embryos. Furthermore, the number of non-ovulatory cycles (p less than 0.05) and the incidence of abnormality in pre-implantation stage embryos (p less than 0.02) were higher during the months of transition in (October) and out (March) of the breeding season.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Histochemical study on adrenal delta 5-3 beta-hydroxysteroid dehydrogenase activity in cadmium treated toad (Bufo melanostictus).

Effect of a single subcutaneous injection of cadmium chloride at the dose of 0.5 mg/toad on adrenal delta 5-3 beta-hydroxysteroid dehydrogenase (delta 5-3 beta-HSD) was observed after 7 days. The activity of delta 5-3 beta-HSD was measured histochemically. The experiments indicate that cadmium chloride resulted in a significant decrease in the activity of adrenal delta 5-3 beta-HSD in toad during breeding season (June-July).

3-Hydroxysteroid Dehydrogenases↗