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Biomedical subjects

R Sharma

Publications and source records attributed to R Sharma.

At least 577 records · Page 32Linked to original sources
PubMed1987

Age-dependent activation of glucocorticoid receptors in the liver of male rats.

The binding of hepatic [3H] dexamethasone-receptor complexes to DNA-cellulose and purified nuclei was studied in the immature (3-week) and mature (26-week) Long-Evans male rats to determine the age-associated changes, if any, in the physicochemical properties of glucocorticoid-receptors. Our data show that heat activation (for 45 min at 25 degrees C) significantly enhances the binding of [3H] dexamethasone-receptor complexes to DNA-cellulose and purified nuclei at both the ages, with a greater magnitude in mature rats. Cross-mixing experiments (i.e. binding of activated cytosol from mature rats to nuclei of immature and vice-versa) show receptor specificity. Ca2+ activation (20mM Ca2+ for 45 min at 0 degrees C) also enhances the nuclear and DNA-cellulose binding at both the ages but to a similar extent. These findings indicate that some of the physicochemical properties (e.g. heat activation) of glucocorticoid receptor change, while others (e.g. Ca2+ activation) remain unchanged at these phases of the life span. The observed changes may lead to functional alterations in the tissue response as a function of age.

Aging↗
PubMed1987

Keratomycosis in corneal sepsis.

510 cases of corneal ulceration were studied for the presence of fungus as a causative organism. Fungus was found in 87 (17.5%) most common fungus found was aspergillus. Mucor was found in 16 cases (18.1%) which is higher than earlier reports. History of trauma specially with vegetative matter and the application of steriods for one purpose or the other is a factor of importance as noted in this study.

Cohort Studies↗
PubMed1987

Pretreatment dexamethasone suppression test as a predictor of response to phenelzine.

Twenty inpatients who met Research Diagnostic Criteria and DSM-III criteria for depression underwent a 2-week washout period before the administration of a pretreatment dexamethasone suppression test (DST); the patients then received the monoamine oxidase inhibitor (MAOI) phenelzine. The mean MAO inhibition level achieved during treatment was greater than 80%. On the basis of clinical global evaluation and changes in Hamilton Rating Scale for Depression scores, 7 of the 9 baseline DST suppressors were classified as responders, 1 as a partial responder, and 1 as a nonresponder; of the 11 baseline DST nonsuppressors, 3 were responders, 1 a partial responder, and 7 nonresponders. The Mann-Whitney U test yielded p less than .02, indicating that an abnormally high pretreatment level of cortisol in response to the DST appeared to be predictive of nonresponse to phenelzine.

Adult↗
PubMed1986

Heat shock (45 degrees C) results in an increase of nuclear matrix protein mass in HeLa cells.

The nuclear matrix from HeLa cells heated at 45 degrees C was isolated to determine the effect of thermal shock on its composition and structure. The matrix from unheated cells contained about 10 per cent of total cell protein and was observed to be spherical particle with a diameter ranging from 3 to 5 microns with the major constituent polypeptides having molecular weights of 45, 47, 55, 57, 59 and 65 kilodaltons. The nuclear-matrix protein mass increased linearly with increasing exposure time at 45 degrees C with no observable change in its size or shape. The additional proteins were observed in general to have molecular weights greater than 45 kilodaltons, with marked increases in polypeptides of 28.5, 38.5, 60, 66, 75, 81, 88, 100 and 115 kilodaltons. An exponential relationship was observed between heat-induced cytotoxicity and the nuclear matrix protein mass increase. A 15 per cent increase in matrix protein mass was sustained prior to the onset of cytotoxicity, while a 35 per cent increase in matrix protein content was associated with a 63 per cent probability of cell killing. The results indicate that redistribution of cell protein or alterations in the mass or structure of the nuclear matrix may be involved in heat-induced cytotoxicity.

Cell Fractionation↗
PubMed1986

Aluminium phosphide poisoning: a prospective study of 16 cases in one year.

Sixteen patients suffering from aluminium phosphide poisoning were treated during the year from January 1985 to December 1985. These accounted for approximately half the total number of cases of acute poisoning. Profuse vomiting, pain in the upper abdomen and shock were the most common presenting features. Six patients succumbed to their illness. Analysis of various prognostic factors revealed that ingestion of 'unexposed' tablets of aluminium phosphide taken from a freshly opened bottle was associated with a greater risk of fatal outcome. Aluminium phosphide poisoning has become an important matter of public health in parts of India.

Abdomen↗
PubMed1986

Effects of exogenous progesterone following ovariectomy on the metrial glands of pregnant mice.

The numbers of granulated metrial gland cells, the percentage of them incorporating tritiated thymidine and the numbers of granulated metrial gland cell precursors in a defined area of the metrial gland, and the cross sectional area of the metrial gland, have been determined in mice ovariectomised on Day 8 of pregnancy. The effects, on these parameters and on fetal survival, of progesterone treatment, given at two levels (0.5 mg or 1 mg twice daily) and started immediately after ovariectomy or after 6, 10 or 24 hours delay, have been studied. Granulated metrial gland cell number, DNA synthetic activity and metrial gland size decreased rapidly after ovariectomy but there was a significant increase in the number of granulated metrial gland cell precursors in the first 24 hours. Progesterone treatment, at the higher dose level started immediately after ovariectomy, resulted in significantly more granulated metrial gland cells in the area analysed two days after ovariectomy although a normal proportion of them were in DNA synthesis. Immediate progesterone treatment, at the higher dose level, was able to prolong the DNA synthetic activity of granulated metrial gland cells until Day 19 and this probably accounted for the significantly greater numbers of granulated metrial gland cells in these mice than in control mice, at this time. Delaying progesterone treatment at the higher level by 24 hours significantly reduced the size of the metrial glands at Day 10 but there was no effect on the cellular composition of the area analysed. Delaying the lower dose of progesterone treatment by 24 hours also resulted in small metrial glands and was associated with significantly fewer granulated metrial gland cells in the area analysed but significantly more of them were synthesising DNA. The observations are discussed and an attempt is made to relate the effects on individual fetal and placental survival to the effects on the corresponding metrial glands.

Animals↗
PubMed1986

Changes in glucocorticoid receptors in different regions of brain of immature and mature male rats.

Specific cytosolic binding for synthetic glucocorticoid dexamethasone was studied in several brain regions (hypothalamus, hippocampus, caudate nucleus, cerebellum, cerebral cortex) of immature (3-week) and mature (26-week) male rats, intact and adrenalectomized. A significant regional difference was observed in the concentration of in vitro [3H] dexamethasone binding in the brain of adrenalectomized rats at both ages, with the highest levels in the hippocampus. A marked decrease in specific binding was observed in all brain regions of adrenalectomized mature rats as compared to immature. The dexamethasone binding was significantly lower in all brain regions of normal intact animals as compared to adrenalectomized rats in both ages.

Aging↗
PubMed1985

Affinity chromatography of mustard beta-amylase on starch columns.

An affinity chromatography method for purification of beta-amylase from cotyledons of white mustard seedlings (Sinapis alba L.) is described. beta-Amylase is bound to starch column, while other contaminating proteins are eluted with the binding buffer. The bound beta-amylase is eluted by including dextrin (1%, w/v) in binding buffer. This method yielded a homogeneous preparation of beta-amylase enzyme, which migrated as a single polypeptide band in SDS gel electrophoresis.

Amylases↗
PubMed1985

Effects of 2-deoxy-D-glucose on glycolysis, proliferation kinetics and radiation response of human cancer cells.

The effects of 2-deoxy-D-glucose (2-DG) on energy metabolism, cell proliferation kinetics, radiation-induced DNA repair, and micronuclei formation in HeLa cells have been studied. Results show that the 2-DG induced modifications of the radiation effects are biphasic: at high 2-DG concentrations (greater than 2.5 mM), DNA repair is inhibited and manifestation of radiation damage is enhanced as observed by an increase in the radiation (X ray) induced micronuclei formation; lower concentrations of 2-DG (less than 2.5 mM) do not inhibit DNA repair and a decrease in the frequency of micronuclei formation is observed. These data, in correlation with the effects of 2-DG on glycolysis and cell proliferation kinetics, can be explained by the hypothesis that 2-DG induced modifications of radiation effects arise as a result of energy linked differential inhibitions of pathways of repair and fixation of DNA damage. Implications for cancer therapy are discussed.

Cell Division↗
PubMed1985

Serum thyroxine and triiodothyronine concentrations in rats receiving lithium carbonate.

Circulating thyroxine (T4) and triiodothyronine (T3) concentrations in rats were determined after various periods of lithium administration in diet. No significant change in serum T4 and T3 levels was observed after ten days of lithium treatment. However, lithium treatment for one month, two months and four months showed a significant decrease in serum T4 and T3 levels indicating the adverse effect of chronic lithium intake.

Animals↗
PubMed1985

Cell mediated immune response following foot-and-mouth disease vaccination in buffalo calves.

The cell mediated immune (CMI) response was studied by E-rosette formation in vitro and delayed type hypersensitivity (DTH) skin reaction in buffalo calves vaccinated with monovalent type 0 as well as with a polyvalent foot-and-mouth disease vaccine. Up to 35 days post-vaccination there was a significant increase (P less than 0.05) in the number of T-lymphocytes in both animal groups. Thereafter, the number of lymphocytes decreased. Delayed type hypersensitivity (DTH) skin reaction was characterized by a significant increase in skin thickness; histology showed mononuclear infiltration and perivascular cuffing.

Animals↗