Search PubMed⌕ Search

Biomedical subjects

D Ghosh

Publications and source records attributed to D Ghosh.

At least 199 records · Page 11Linked to original sources
PubMed1991

Three-dimensional structure of holo 3 alpha,20 beta-hydroxysteroid dehydrogenase: a member of a short-chain dehydrogenase family.

The x-ray structure of a short-chain dehydrogenase, the bacterial holo 3 alpha,20 beta-hydroxysteroid dehydrogenase (EC 1.1.1.53), is described at 2.6 A resolution. This enzyme is active as a tetramer and crystallizes with four identical subunits in the asymmetric unit. It has the alpha/beta fold characteristic of the dinucleotide binding region. The fold of the rest of the subunit, the quaternary structure, and the nature of the cofactor-enzyme interactions are, however, significantly different from those observed in the long-chain dehydrogenases. The architecture of the postulated active site is consistent with the observed stereospecificity of the enzyme and the fact that the tetramer is the active form. There is only one cofactor and one substrate-binding site per subunit; the specificity for both 3 alpha- and 20 beta-ends of the steroid results from the binding of the steroid in two orientations near the same cofactor at the same catalytic site.

Amino Acid Sequence↗
PubMed1991

Functional differentiation of mouse uterine epithelial cells grown on collagen gels or reconstituted basement membranes.

Epithelial cells were isolated from mouse endometrium and cultured on two types of extracellular matrix, namely, rat-tail collagen (type I) gels and basement membrane extract (BME) derived from the Engelbreth-Holm-Swarm murine sarcoma. Cell attachment in serum-free medium during the initial 24 h after seeding was approximately twofold higher on BME compared with collagen type I. Addition of serum to the medium enhanced cell attachment on both matrices. On both collagen and BME, uterine cells grew as smooth-bordered colonies, and within a week of culture the cells became cuboidal to columnar in shape. Electron microscopy revealed the presence of apical microvilli associated with a glycocalyx, junctional complexes, tonofilaments, short strands of undilated endoplasmic reticulum, Golgi complex, and lipid droplets. However, cells on BME showed a higher degree of differentiation as assessed by occasional formation of small patches of basement membranelike structure subjacent to the flattened basal surface and formation of glandlike structures within the matrix. Proliferation of these cells as measured by radioactive thymidine incorporation into DNA was increased threefold by addition of epidermal growth factor (EGF) and insulin to the medium, but was not changed by 17 beta-estradiol. The expression of progesterone receptors by uterine epithelial cells grown on both matrices was doubled by addition of EGF and estradiol to the medium.

Animals↗
PubMed1991

Effect of lithium chloride on spermatogenesis and testicular steroidogenesis in mature albino rats: duration dependent response.

Quantitative evaluation of the different varieties of germ cells at stage VII of the seminiferous epithelium cycle, namely type-A spermatogonia (ASg), preleptotene spermatocytes (pLSc), midpachytene spermatocytes (mPSc) and step 7 spermatids (7 Sd) along with Leydig cell nuclear area (LCNA) and radioimmunoassay of plasma levels of gonadotropins (FSH and LH), prolactin (PRL) and testosterone (T), activities of testicular, delta 5-3 beta hydroxysteroid dehydrogenase (delta 5-3 beta-HSD) and 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) were measured in mature rats of the Wistar strain following treatment with lithium chloride at a dose of 200 ug/100 g body wt/day for 7,14 and 21 days. A remarkable reduction in plasma levels of FSH (P less than 0.001), LH (P less than 0.05, P less than 0.01), PRL (P less than 0.05, P less than 0.001) and T (P less than 0.001) along with significant diminution in the activities of testicular delta 5-3 beta-HSD (P less than 0.001) and 17 beta-HSD (P less than 0.001) were observed following lithium treatment for 14 and 21 days. 21 days of treatment also resulted a marked degree of degeneration of ASg (P less than 0.05) and 7Sd(P less than 0.001) at stage VII but 14 days of treatment did not exhibited any significant effect on testicular gametogenesis. LCNA was decreased after lithium chloride treatment for 14 and 21 days (P less than 0.001). 7 days of treatment did not exert any notable result in the above parameters. The results of our experiment suggest that duration of lithium treatment is the critical factor for its adverse effects on testicular activity when the plasma levels of lithium remain within the therapeutic range. The possibility of an indirect action of lithium at the level of the testes is also discussed. Hence the data of our experiments have potential clinical implication.

17-Hydroxysteroid Dehydrogenases↗
PubMed1991

Crystallization and preliminary diffraction analysis of cholesterol esterase from Candida cylindracea.

Cholesterol esterase (EC 3.1.1.13) from the microorganism Candida cylindracea has been crystallized in two forms. Crystals, typically 0.30 x 0.15 x 0.10 mm in size, diffract rotating anode generated x-rays to beyond 3 A are suitable for data collection for an x-ray crystallographic investigation. A monoclinic crystal form in the space group P2(1) was found to have cell dimensions of a = 122.9 A, b = 101.0 A, c = 95.2 A and beta = 108.3 degrees. The asymmetric unit of the cell contains two dimers of 129 kDa each. A second crystal form, in the triclinic space group P1, has cell dimensions of a = 58.6 A, b = 88.7 A, c = 58.6 A, alpha = 93.3 degrees, beta = 113.8 degrees and gamma = 96.0 degrees, and has one dimer per asymmetric unit.

Candida↗
PubMed1991

Selective embolization of internal iliac artery for massive haemorrhage from bladder secondary to carcinoma.

Uncontrolled haemorrhage from the urinary bladder secondary to carcinoma can at times be a life-threatening complication. We report a case of recurrent carcinoma of bladder where all the conservative measures for controlling hematuria had failed. Selective embolization of both internal iliac arteries was undertaken which controlled haematuria within 12 hours of the procedure. The procedure had not caused any complication up until the patient was last seen 5 months after the procedure.

Carcinoma, Transitional Cell↗
PubMed1991

Effect of lithium chloride on testicular steroidogenesis and gametogenesis in immature male rats.

The present study was performed on immature male rats aged 35 days. Subcutaneous injections of lithium chloride at a daily dose of 2.0 mg/kg for 15 days resulted in significant inhibition of spermatogenesis at stage VII of the seminiferous epithelial cycle. Spermatogonia A, preleptotene spermatocytes and step 7 spermatids were decreased in number in comparison to controls. Serum levels of FSH, LH, PRL, and testosterone were decreased. Activities of testicular delta 5-3 beta-hydroxysteroid dehydrogenase and 17 beta-hydroxysteroid dehydrogenase were suppressed along with a low caudal epididymal sperm count in comparison with controls. When the treatment was prolonged for 20 and 25 days, it showed an additional significant diminution in accessory sex organ weights and number of midpachytene spermatocytes at stage VII in comparison to control animals of corresponding age. It is concluded that lithium has an adverse effect on testicular function in immature rats by reducing serum levels of FSH, LH, PRL, and testosterone. Furthermore, since hormonal changes and altered spermatogenic activities were evident when the serum concentration of lithium was within the therapeutic range, our data may have some potential clinical implications.

17-Hydroxysteroid Dehydrogenases↗
PubMed1991

Studies on the effect of prolactin treatment on testicular steroidogenesis and gametogenesis in lithium-treated rats.

The effect of PRL supplementation in lithium-treated rats on spermatogenesis, testicular delta 5-3 beta-hydroxysteroid dehydrogenase and 17 beta-hydroxysteroid dehydrogenase activities, and serum levels of FSH, LH, PRL and testosterone were studied on the 22nd day of the experiment. Subcutaneous injections of lithium chloride at a dose of 2.0 mg.kg-1.day-1 for 21 days resulted in a significant inhibition of spermatogenesis at stage VII of the seminiferous epithelial cycle, along with remarkable diminution of serum levels of the above hormones and suppression of the activities of the above two testicular steroidogenic enzymes. Administration of bovine PRL at a dose of 0.25 mg.kg-1.day-1 plus lithium treatment resulted in a remarkable protection of spermatogenic and steroidogenic activities of the testes, along with restoration of serum levels of FSH and testosterone. It is concluded that PRL can markedly protect the testicular dysfunction induced by lithium chloride treatment in rats.

17-Hydroxysteroid Dehydrogenases↗
PubMed1991

Changes in the testicular acid and alkaline phosphatase activities at different durations following prostatectomy: a correlative study with spermatogenesis.

The purpose of this investigation was to make a correlative study between spermatogenesis and testicular acid and alkaline phosphatase activities in mature prostatectomized animals at different post-operative periods. The results demonstrate that there was a significant augmentation in the activity of testicular acid and alkaline phosphatases subsequent to 14 and 21 days of prostatectomy. A parallel quantitative study of spermatogenesis at stage VII of the seminiferous cycle, namely, type A spermatogonia (ASg), preleptotene spermatocytes (pLSc), mid-pachytene spermatocytes (mPSc) and step 7 spermatids (7sd), revealed that there was a significant reduction in the number of step 7 spermatids after 14 and 21 days. No change was observed in the above testicular enzymes and spermatogenesis after 7 days of prostatectomy. Therefore, it is concluded that prostatectomy can alter the above testicular enzyme activities and spermatogenesis in chronic prostatectomized state.

Acid Phosphatase↗
PubMed1991

Myositis ossificans progressiva.

Myositis ossificans progressiva is a rare, incurable disease causing progressive ossification of skeletal muscles leading to total immobility. We report one such case.

Adult↗
PubMed1990

A relational database of transcription factors.

Recent advances in the understanding of eukaryotic gene regulation have produced an extensive body of transcriptionally-related sequence information in the biological literature, and have created a need for computing structures that organize and manage this information. The 'relational model' represents an approach that is finding increasing application in the design of biological databases. This report describes the compilation of information regarding eukaryotic transcription factors, the organization of this information into five tables, the computational applications of the resultant relational database that are of theoretical as well as experimental interest, and possible avenues of further development.

Amino Acid Sequence↗
PubMed1990

Effects of lithium chloride on testicular steroidogenic and gametogenic functions in mature male albino rats.

The present study was undertaken to evaluate the effects of lithium, an antimanic drug, on steroidogenic and gametogenic functions of testis in the laboratory rat. Adult male rats of Wistar strain maintained under standard laboratory conditions (L:D, 14h:10h), were injected (S.C) with lithium chloride at the dose of 0.1 mg, 0.2 mg and 0.4 mg/100 g body weight/day for 21 days. All the treated animals along with the vehicle treated controls were sacrificed 24 hours after the last injections. Testicular steroidogenic activity was evaluated by measuring the activities of two steroidogenic key enzymes, delta 5-3 beta hydroxysteroid dehydrogenase (delta 5-3 beta-HSD) and 17 beta hydroxysteroid dehydrogenase (17 beta-HSD). Gametogenic capacity was determined by counting the number of germ cells at stage VII of seminiferous cycle. Plasma levels of follicle stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL) and testosterone (T) were measured by radioimmunoassay (RIA). Administration of lithium chloride at a dose of 0.1 mg/100 g body wt. for 21 days led to insignificant changes of plasma FSH, LH, PRL and T along with unaltered activities of testicular delta 5-3 beta-HSD, 17 beta-HSD activities and gametogenesis. In contrast, 0.2 mg of lithium treatment for 21 days causes a significant reduction of plasma FSH (P less than 0.01), LH (P less than 0.001), PRL (P less than 0.001) and T (P less than 0.001) along with inhibition of testicular delta 5-3 beta-HSD activity (P less than 0.01) and 17 beta-HSD activity (P less than 0.001). Gametogenic activity does not exhibits any significant reduction in the number of preleptotene spermatocytes (PLSc) and midpachytene spermatocytes (mPSC) while significant reduction in the number of spermatogonia A (Asg) (P less than 0.01) and Step 7 spermatids (7Sd) (P less than 0.001) were observed at stage VII of seminiferous cycle when compared to control. The degree of detrimental effects of lithium on testicular activity became more prominent at the dose of 0.4 mg/100 g body wt. The results of our experiments suggest that lithium administration might be associated with significant adverse effects on testicular activities. Furthermore, since hormonal changes and altered gametogenic activities were evident when plasma lithium concentration was below or within the therapeutic range, our data may have some potential clinical implications.

Animals↗
PubMed1990

cis-acting regulatory elements near the Epstein-Barr virus latent-infection membrane protein transcriptional start site.

Epstein-Barr virus (EBV) latent-infection membrane protein (LMP) gene cis-acting regulatory sequences were assayed in human B lymphocytes by using chloramphenicol acetyltransferase (cat) gene expression as a reporter. The activities of progressively longer upstream elements from bases -55 to -2350 were compared. At least two positive cis-activating regulatory components (-155 to -147 and -234 to -205) upstream of the LMP promoter were defined. LMP promoter cat gene constructs were more active in a Burkitt's lymphoma cell line latently infected with the B95 EBV strain than in the same cells latently infected with the P3HR1 EBV strain. Since the P3HR1- and B95-infected cells differ in EBNA-2 and EBNA-LP expression, EBNA-2 or EBNA-LP is a likely transactivator of the LMP promoter. Probable cognate sequences for known transcription factors in the LMP promoter are discussed.

Antigens, Viral↗