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Biomedical subjects

L R Singh

Publications and source records attributed to L R Singh.

At least 19 recordsLinked to original sources
PubMed2006

Emergence of sporotrichosis in Manipur.

A retrospective analysis of all cases of sporotrichosis was conducted to examine the pattern and frequency of sporotrichosis cases in Manipur over a period of six year from July 1999 to June 2005. Seventy-three (73) cases of sporotrichosis were detected of which 30 were confirmed by culture and 43 were diagnosed by aspiration cytology only. Most of the patients belonged to the age group of 21 to 40 years (n = 23; 31.5%). There were 39 females (53.4%) and 34 males (46.5%). Commonest site of infection was upper limbs (n = 39; 53.4%) followed by lower limbs (n = 17; 23.2%). Commonest type of infection was lymphocutaneous form (n = 46; 63.1%) followed by fixed cutaneous form (n = 27; 36.9%). Among these 73 cases, 2 male patients (2.7%) were found to be HIV positive. In our experience, collection of material by aspiration of pus or infected tissue was found to be a better method compared to scraping or exudate. This study revealed Manipur as a new endemic area for sporotrichosis.

Adolescent↗
PubMed1998

Effects of hypothyroidism and hyperthyroidism on serum glycoproteins in experimental rats.

Hypothyroidism and hyperthyroidism were induced in adult female Sprague Dawley rats by feeding 0.05% propylthiouracil and 0.0012% L-thyroxine in drinking water. Contents of protein-bound hexose, fucose, hexosamine and sialic acid in serum were estimated in experimental rats. The results showed an increase in the protein bound hexose, fucose, hexosamine and sialic acid levels in hypothyroid rats and decrease in hyperthyroid rats. The increased content of serum glycoproteins in hypothyroid rats might possibly have come from disruptions of membranes. Depleted glycoproteins in hyperthyroid animals might be due to increase in depolymerisations of glycoproteins and accelerated secretion of glycoproteins with urine.

Animals↗
PubMed1993

Blood and hepatic glutathione in linamarin fed rats.

Female Sprague Dawley rats were fed 5 mg linamarin daily for 10 days. Reduced glutathione (GSH) levels in blood and liver of experimental rats were analysed. The results showed an increase of 45% and 33% glutathione levels in blood and liver respectively in experimental rats. This alteration in glutathione levels could be most likely either due to increased hepatic biosynthesis or as a consequence of decreased peripheral utilization which might be appreciated due to hypothyroidal status induced by linamarin feeding.

Animals↗
PubMed1989

Effect of substrates and coenzymes on the molecular symmetry-related properties of horse liver and yeast alcohol dehydrogenases.

Thermal inactivation of horse liver alcohol dehydrogenase (LADH) exhibits the following biphasic kinetics A = Afast.e-Kfast.t + Aslow.e-Kslow.t Where A is the per cent residual activity at time t,Afast and Aslow are amplitudes (expressed as % of initial activity) and kfast and kslow first-order rate constants of the fast and slow phases, respectively. For apoenzyme, Afast = Aslow = 50% of the initial activity under all conditions of temperature and pH. On the addition of a substrate or coenzyme ligand, there is a ligand concentration-dependent increase in per cent Aslow and a decrease in kslow. At sufficiently high ligand concentration, the entire time-course of inactivation can be described as a single exponential decay. The variations of per cent Aslow and of kslow with ligand concentration are consistent with the existence of two binding sites of different ligand affinities. Inactivation of LADH by excess EDTA also exhibits a similar biphasic kinetics with Afast = Aslow = 50% of the initial activity. Addition of ethanol or NAD+ brings about a concentration-dependent decrease in kfast and kslow without affecting amplitudes of the two phases. The NAD+ concentration-dependence of this decrease is consistent with a single dissociation constant for the coenzyme. Inactivation of yeast alcohol dehydrogenase by heat or excess EDTA can be represented as a single exponential decay of activity under all conditions of temperature and pH in the absence as well as presence of ethanol or NAD+. Implications of these results for the molecular symmetry of the two oligomeric enzymes in solution are discussed.

Alcohol Dehydrogenase↗
PubMed1987

Effect of whole body gamma-radiation on glutathione reductase of rat tissues.

Adult female Sprague Dawley rats approximate ten months old were exposed to whole body gamma radiation of sublethal (4 Gy) and lethal (10 Gy) doses of radiation. Serum glutathione reductase enzyme values of 4 Gy exposed rats did not show any change on first and fourth day but significantly decreased on eighth day, while enzyme values in 10 Gy exposed group remained unaltered throughout. Heart glutathione reductase activities of sublethal group did not show any change on first and eighth day but significantly decreased on fourth day. Rats exposed to lethal doses of radiation, enzyme activities remained unchanged throughout. Liver glutathione reductase enzyme values of 4 Gy exposed group showed significant decrease on first and fourth day but arrived at control values on eighth day while the same in 10 Gy exposed group showed significant decrease from first day till the eighth day. An appreciable diminution was observed in spleen glutathione reductase enzyme activities of sublethal and lethal exposed rats from first day till eighth day.

Animals↗
PubMed1984

Effect of ionizing radiation on tissue cyclic AMP and GMP in experimental rats.

Adult male Sprague Dawley rats were exposed to whole-body gamma radiation of 4 Gy and 10 Gy and cyclic AMP and GMP of several tissues were studied 4 hours, 24 hours and 72 hours after irradiation. Animals exposed to 4 Gy exhibited initial increase and subsequent decrease of plasma cyclic AMP, while opposite effects were noted in plasma cyclic GMP. Both groups of irradiated rats showed significant decrease of spleen cyclic AMP with variable responses in cyclic GMP. Initial increase with subsequent decrease of liver cyclic AMP was observed in irradiated animals with unaltered cyclic GMP values. It was interesting to note variable responses of myocardial cyclic AMP in both groups of experimental rats with a significant increase in heart cyclic GMP in rats exposed to 10 Gy only. In contrast, myocardial cyclic GMP was significantly decreased in rats exposed to 4 Gy groups.

Animals↗
PubMed1983

Molecular asymmetry in alkaline phosphatase of Escherichia coli.

Thermal inactivation of alkaline phosphatase of Escherichia coli has been studied at different temperatures (45 to 70 degrees C) and pHs (7.5, 9.0, and 10.0) for the commercial, buffer-dialyzed (pH 9.0) and EDTA-dialyzed (pH 9.0) enzymes. In each case, the inactivation exhibits biphasic kinetics consistent with the rate equation, (formula; see text) where A0 and A are activities at time zero and t, and k1 and k2 are first-order rate constants for the fast and slow phase, respectively. Values of k1 and k2 change independently with temperature, pH, and pretreatment (dialysis) of the enzyme. Time course of inactivation of the enzyme with excess EDTA and effect of Zn2+ ion concentration on the activity of EDTA-dialyzed enzyme have been investigated. The data suggest that the dimeric enzyme protein has two types of catalytic sites which have equal catalytic efficiency (or specific activity) but differ in several other properties. Structural implications of these results have been discussed.

Alkaline Phosphatase↗
PubMed1983

Effect of whole body gamma radiation on reduced glutathione contents of rat tissues.

Reduced glutathione (GSH) contents of blood, heart, liver and spleen were studied after one, four and seven days of irradiation in rats. Blood GSH in rats exposed to 4 Gy remained unaltered throughout, while animals exposed to 8 Gy showed significant decrease of blood GSH on the 8th day after exposure. Diminution of liver and heart GSH contents was observed initially in both groups of irradiated rats, while the reverse was noted in spleen GSH contents of experimental animals.

Animals↗
PubMed1982

Effect of low environmental temperature on adenylate cyclase and phosphodiesterase in rat tissues.

Adult rats were exposed to 5 degrees C for 5 and 24 h and thereafter the adenylate cyclase and phosphodiesterase (EC were studied in heart and liver. The cold exposure caused a significant increase in the myocardial adenylate cyclase with a simultaneous decrease of the phosphodiesterase activity. Long term cold exposure exhibited a decrease in the adenylate cyclase activity and an increase in the phosphodiesterase activity in rat liver.

Adenylyl Cyclases↗
PubMed1982

Effect of whole-body gamma radiation on some metals of rat plasma.

Adult male rats were exposed to 4 and 10 Gy of whole-body gamma radiation, and several metals of plasma were studied on 1st, 3rd and 6th day after exposure. Lethal radiation increased plasma calcium initially with subsequent diminution, while plasma magnesium decreased initially in both groups, becoming normal on the 6th day post exposure. Plasma iron in 4-Gy exposed rats diminished on 3rd day, while the same in 10-Gy exposed animals increased initially and then decreased. Both groups of animals exhibited significant diminution of plasma copper and ceruloplasmin from the 3rd day post irradiation. Plasma monoamine oxidase (MAO) was enhanced from 1st day post exposure in 10-Gy exposed rats, which persisted still 6th day. Liver monoamine oxidase was significantly diminished from 1st day after exposure in lethally exposed rats, while spleen monoamine oxidase, after initial increase was normalised on 6th day post irradiation.

Animals↗