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Biomedical subjects

D Ghosh

Publications and source records attributed to D Ghosh.

At least 271 records · Page 15Linked to original sources

Antemortem diagnosis of Leigh's disease: role of magnetic resonance studies.

A two-and-a-half-year-old male child presented with recurrent attacks of intractable vomiting, psychomotor retardation since 14 months of age. He had also lower cranial nerve palsy and corticospinal involvement. Magnetic resonance imaging had shown multiple well circumscribed areas of hypointusity in T1 weighted image which were brightly hyperintense in heavily T2-weighted image. The lesions were seen in basal ganglia, thalamii and brainstem and spared mamillary bodies. Magnetic resonance spectroscopy demonstrated lactate peak in the affected areas confirming the diagnosis of Leigh's disease. The child responded well to large dose of vitamin 'B' therapy.

Brain↗

Role of progesterone on peri-implantation stage endometrium-embryo interaction in the primate.

Progesterone secretion during the luteal phase influences oviductal and endometrial functions which are essential for embryo viability and implantation in a number of species including primates. Luteal phase estrogen is not essential for progesterone-dependent endometrial receptivity towards implantation and pregnancy in the rhesus monkey and in the human. However, synchronous development of embryo and endometrium is an essential prerequisite for evolutive implantation. Progesterone helps to maintain synchronous development of preimplantation embryo through its action on maternal uterus. The anti-nidatory action of mifepristone, a potent progesterone receptor modulator (PRM) with pronounced antiprogestagenic activity, is known to be associated with desynchronization of endometrium along with repression of glandular secretory differentiation and vascular maturation. Thus, it is likely that early luteal phase administration of mifepristone affects paracrine action of the secretory stage endometrium on the preimplantation stage embryo, and thereby inhibits embryonic development and viability. We shall examine this hypothesis using the rhesus monkey as a primate model.

Animals↗

Structural perturbation of alpha-crystallin and its chaperone-like activity.

alpha-Crystallin is a multimeric lenticular protein that has recently been shown to be expressed in several non-lenticular tissues as well. It is shown to prevent aggregation of non-native proteins as a molecular chaperone. By using a non-thermal aggregation model, we could show that this process is temperature-dependent. We investigated the chaperone-like activity of alpha-crystallin towards photo-induced aggregation of gamma-crystallin, aggregation of insulin and on the refolding induced aggregation of beta- and gamma-crystallins. We observed that alpha-crystallin could prevent photo-aggregation of gamma-crystallin and this chaperone-like activity of alpha-crystallin is enhanced several fold at temperatures above 30 degrees C. This enhancement parallels the exposure of its hydrophobic surfaces as a function of temperature, probed using hydrophobic fluorescent probes such as pyrene and 8-anilinonaphthalene-1-sulfonate. We, therefore, concluded that alpha-crystallin prevents the aggregation of other proteins by providing appropriately placed hydrophobic surfaces; a structural transition above 30 degrees C involving enhanced or re-organized hydrophobic surfaces of alpha-crystallin is important for its chaperone-like activity. We also addressed the issue of conformational aspects of target proteins and found that their aggregation prone molten globule states bind to alpha-crystallin. We trace these developments and discuss some new lines that suggest the role of tertiary structural aspects in the chaperone process.

Animals↗

Effect of human chorionic gonadotrophin coadministration on ovarian steroidogenic and folliculogenic activities in cyclophosphamide treated albino rats.

Quantitative evaluation of ovarian Delta5,3beta- hydroxysteroid dehydrogenese (HSD) and 17beta - HSD activities along with radioimmunoassay of plasma levels of gonadotrophins (FSH and LH), and estradiol (E2), and quantification of different types of developing follicles and regressive follicles were noted in mature rats of the Wistar strain following treatment with cyclophosphamide at a dose of 5 mg/kg body weight/day for 28 days. A significant reduction in plasma levels of LH and E2 along with significant diminution in the activities of ovarian Delta5,3beta -HSD and 17beta- HSD were observed following cyclophosphamide treatment for 28 days without any change in the plasma level of FSH. This treatment also produced a marked degree of degeneration in different types of follicles. Coadministration of hCG at 5 IU/kg body weight/day for 28 days in the cyclophosphamide-treated group provided significant protection except with respect to plasma LH. These results suggest the possibility of an indirect action of cyclophosphamide at the level of the ovary.

17-Hydroxysteroid Dehydrogenases↗

Effect of human chorionic gonadotrophin coadministration on the activities of ovarian Delta5-3beta-hydroxysteroid dehydrogenase, and 17beta-hydroxysteroid dehydrogenase, and ovarian and uterine histology in lithium chloride-treated albino rats.

Lithium chloride, a compound with clinical use in bipolar disorder, produces adverse effects on ovarian function in amphibian and rodent models. This study examined the effect of human chorionic gonadotrophin coadministration on ovarian steroidogenic and gametogenic activities in lithium chloride-treated rats. Relative ovarian and uterine weights, ovarian Delta(5)-3beta-hydroxysteroid dehydrogenase and 17beta-hydroxysteroid dehydrogenase activities, folliculogenesis, uterine diameter, endometrial and myometrial thickness, and uterine luminal epithelial height were decreased significantly after lithium chloride treatment for 28 days at 1.6 mg/kg/day, the human therapeutic dose. These parameters were unchanged from the control level when subcutaneous (s.c.) human chorionic gonadotrophin (hCG) at 25 microg/kg/day was coadministered with the lithium chloride. The duration of the oestrous cycle was increased in lithium chloride-treated rat with longer metestrous and diestrous phases. Administration of hCG with lithium chloride prevented these estrous cycle alterations. We conclude that hCG can protect ovarian steroidogenic and gametogenic function after lithium chloride treatment.

17-Hydroxysteroid Dehydrogenases↗

Testicular toxicity in sodium fluoride treated rats: association with oxidative stress.

This study examined the effect of sodium fluoride, a water pollutant important through the world, including India, on testicular steroidogenic and gametogenic activities in relation to testicular oxidative stress in rats. Sodium fluoride treatment at 20mg/kg/day for 29 days by oral gavage resulted in significant diminution in the relative wet weight of the testis, prostate, and seminal vesicle without alteration in the body weight gain. Testicular delta(5),3beta-hydroxysteroid dehydrogenase (HSD) and 17beta-HSD activities were decreased significantly along with significant diminution in plasma levels of testosterone in the fluoride-exposed group compared to the control. Epididymal sperm count was decreased significantly in the fluoride-treated group and qualitative examination of testicular sections revealed fewer mature luminal spermatozoa in comparison to the control. The seminiferous tubules were dilated in treated animals. Fluoride treatment was associated with oxidative stress as indicated by an increased level of conjugated dienes in the testis, epididymis, and epididymal sperm pellet with respect to control. Peroxidase and catalase activities in the sperm pellet were decreased significantly in comparison to the control. The results of this experiment indicate that fluoride at a dose encountered in drinking water in contaminated areas exerts an adverse effect on the male reproductive system and this effect is associated with indicators of oxidative stress.

17-Hydroxysteroid Dehydrogenases↗

Spinal dysraphism presenting as acro-osteolysis: report of four cases.

The acro-osteolyses are a heterogeneous group of disorders characterized by bone resorption. The disorder may occur as familial, idiopathic, or secondary to vascular, inflammatory, or neurologic conditions. Acro-osteolysis is rare in association with spinal dysraphism. It is even rarer for it to be the presenting symptom in spinal dysraphism. We report here four patients in whom the diagnosis of spinal dysraphism was established while investigating for the various causes of acro-osteolysis. All four patients presented with trophic changes and acro-osteolysis. Hyperhidrosis in the affected limb was seen in three patients. One patient had leg pain, the others had no sensory or motor deficits. Magnetic resonance imaging showed spinal dysraphism in all four patients.

Adolescent↗

Recent developments in endocrinology and paracrinology of blastocyst implantation in the primate.

It is becoming increasingly evident that growth factors and cytokines play crucial roles in the process of blastocyst implantation. Endometrial differentiation and secretions, embryo development and secretions, and embryo-endometrium interaction leading to implantation require continuous and synchronous dialogue between these two compartments involving endocrine and paracrine regulators. In this review, a model of the endocrinology and paracrinology of blastocyst implantation in the primate is described.

Animals↗