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Biomedical subjects

N Sharma

Publications and source records attributed to N Sharma.

At least 217 records · Page 12Linked to original sources
PubMed1990

Induction of error-free DNA repair in Escherichia coli by thiamine deprivation.

Incubation of Escherichia coli AB1157 in a thiamine-deficient medium causes a large, time-dependent increase in resistance to UV-radiation (254 nm) and a fall in its UV-induced mutation frequency to histidine prototrophy which are abolished in its uvrA mutant, but only delayed in lon- and recA- cells. The response of the lexA3 mutant resembles that of the parental cells. These effects are very similar to those we have shown to be induced by heat shock and are clearly due to an error-free, DNA-excision repair-dependent process. They may represent a general response to non-mutagenic stress in these cells.

Bacterial Proteins↗
PubMed1990

Effect of electroconvulsions on glucose homeostasis in rabbits.

Acute electroconvulsions (ECS) produced hyperglycemic response in rabbits which peaked at 30 min and recovered within 4 h. This hyperglycemic response to acute ECS was significantly more marked in rabbits which were chronically pretreated with ECS. The hyperglycemic responses to acute ECS and oral glucose were additive in nature. Daily administration of adrenaline in chronically ECS pretreated rabbits further enhanced the hyperglycemic response to acute ECS. The hyperglycemic response to oral glucose and parenteral adrenaline were significantly more marked in such rabbits. GTT done on the day next to ECS, in rabbits chronically pretreated with ECS and then with ECS plus adrenaline produced enhanced hyperglycemic response. These results indicate that repetitive ECS disturbs glucose homeostasis.

Animals↗
PubMed1990

Haematologic changes in young adult Swiss albino mice after tritiated water administration.

Tritiated water (HTO) injected intraperitoneally to Swiss albino mice at the rate of 370 kBq (10 microCi)/g body weight has been found to cause certain alterations in blood parameters 1, 5, 7 and 15 days postinjectionem. Leucocyte count dropped significantly post treatment. Differential leucocyte counting showed lymphocytes to be most affected which were reduced by 38.29% on 5th day p.i. Erythrocyte count, haemoglobin and haematocrit values though showed no significant changes at early intervals, these values were significantly lower at later intervals than those of control.

Animals↗
PubMed1989

Care of the newborn by traditional birth attendants.

The study was carried out in a slum cum resettlement colony (Area-I) and four villages (Area-II) of Delhi. Management of the newborn by the 25 functioning Traditional Birth Attendants (TBA's) who conducted 83.64% deliveries in Area-I and 16.22% in Area-II was studied. Majority of TBA's did not have the concept of washing hands before conducting per vaginum (P/V) examinations or deliveries. Most of the TBA's, i.e., 21 out of 25 used a razor blade to cut the umbilical cord of which 9 used a fresh blade. No TBA left the cord untied. Vigorous patting in upright and also after holding the baby upside down was the commonest (68%) method of neonatal resuscitation. All TBA's massaged and bathed the baby everyday. Majority of the TBA's (18 out of 25) referred the baby to a health agency for immunization though they did not know the exact schedule.

Delivery, Obstetric↗
PubMed1989

Effects of dexamethasone on lipid metabolism in rat organs.

Injecting of dexamethasone (10 mg/kg body weight) for 8 days to rats decreased the body weight and feed intake by 29 and 50%, respectively. The increase in weights of liver, heart, kidneys and testes per 100 g body weight was 55, 37, 33 and 13%, respectively. Though, in general, the triglyceride content increased in all the organs, maximum increase (9-fold) was observed in the liver. The plasma showed elevated levels of triglycerides, cholesterol and phospholipids. In hepatic mitochondrial membranes, the content of protein, phospholipids and cholesterol decreased/g tissue. The percent 14C distribution, as a part of total incorporation in nonpolar lipids, of [14C]acetate into triglycerides of liver, kidneys and testes increased significantly. The increased turnover of phospholipids in liver and heart was mainly due to increased turnover of phosphatidyl choline (PC) and phosphatidyl ethanolamine in liver and PC in heart. Turnover of phospholipids of testes was not affected.

Animals↗
PubMed1989

Health educators in India--a profile.

While India has a long history of health education, its formal integration into health care services is just three decades old. In addition to providing health education through traditional or informal methods, the country has been stimulating the integration of health education through a professionally trained group of health workers, commonly called: "Health Educators". The impression remains, however, that "information giving" is the primary goal and function of a health educator, and, more often than not, his activities remain confined to publicity. This leads to a debate of the issue of: "who should conduct health education activities, a health education specialist or some other health worker"?

Health Education↗
PubMed1988

Sonographic findings in scrotal brucellosis.

Six patients with scrotal brucellosis were ultrasonically examined. All cases were of acute onset. Concomitant involvement of testes and epididymes were noted in all cases except one in which the epididymis was spared. Abnormal sonographic findings consisted of enlargement of the testes and epididymes, nonhomogenous hypoechoic diffuse, or focal echo patterns in all cases and a hydrocele in one case.

Adult↗
PubMed1988

Alterations in lactate dehydrogenase isoenzymes and phosphofructokinase activity in the hormonally induced G-XII cell line.

G-XII cell line was earlier developed in our laboratory from the granulosa lutein cells of goat ovaries, subjected to sustained stimulation by ovine luteinizing hormone. It is a non-clonogenic and non-tumorigenic cell line which secretes progesterone. In the present paper, we report some biochemical findings on the cell line studied between passages 10 and 15. The cells exhibited a shift in the lactate dehydrogenase isoenzyme pattern from the heart form to muscle form and a 300% increase in the phosphofructokinase activity compared to fresh granulosa cells.

Animals↗
PubMed1987

The fate of thymine-containing dimers in ultraviolet-irradiated Halobacterium cutirubrum.

Extremely halophilic bacteria do not recover in the dark from the effects of ultraviolet radiation, although they can be completely photoreactivated, thus proving that pyrimidine dimers are the cytotoxic photoproducts. We have now shown, by studying the fate of thymine-containing dimers during dark liquid-holding of Halobacterium cutirubrum, that the lack of dark repair in these bacteria is due to their inability to excise such lesions, in contrast to Escherichia coli B. Nevertheless, extensive nonspecific degradation of DNA occurs in H. cutirubrum following ultraviolet irradiation, so the lack of dimer excision is not due to a generalised inability to degrade DNA after such treatment. These findings raise interesting questions concerning the basis of the resistance of halophiles to ultraviolet radiation.

DNA Repair↗
PubMed1987

Studies of adenosine incorporation in Langendorff rat heart and rat heart mitochondria.

The acid-insoluble product isolated from well-oxygenated Langendorff rat heart after perfusion with [14C]adenosine was purified by phenol extraction and subjected to specific phosphorolysis by pure polynucleotide phosphorylase. TLC analysis of the reaction mixture showed that ADP was the only radioactive product, proving that the original substance was a polyribonucleotide. Studies of the time course of labelling and of the distribution of the acid-insoluble product between the mitochondrial and nuclear fractions showed that both are labelled even after 1 min at 25 degrees C, but at short times and low temperature more radioactivity is found in the mitochondria. The kinetics of adenosine incorporation resemble those expected for the labelling of hnRNA and mRNA. Isolated, respiring mitochondria incorporate adenosine and adenine nucleotides into acid insoluble form by a process dependent on oxidative phosphorylation and the adenine nucleotide translocase that is specific for adenine derivatives. The results are discussed in terms of the hypothesis that the polyribonucleotide might be a storage form of adenine nucleotides: it is concluded that the bulk of the labelled product is unlikely to play a major role in energy metabolism.

Adenine Nucleotides↗
PubMed1985

Preparation and properties of highly-purified Vibrio costicola polynucleotide phosphorylase.

Vibrio costicola polynucleotide phosphorylase (polyribonucleotide: orthophosphate nucleotidyltransferase, EC 2.7.7.8) has been purified to electrophoretic homogeneity. It has an approximate molecular weight of 220 000 and consists of identical subunits with an approximate molecular weight of 72 000. The enzyme appears to be a fairly typical polynucleotide phosphorylase with respect to its pH optima, substrate specificity and requirement for a divalent cation cofactor. However, the effect of salt concentration on its physiologically important phosphorolysis activity suggests that it is a moderately halophilic enzyme, able to function at the intracellular ionic strength of the bacterium. In addition, its ADP polymerization activity is remarkably stimulated by polylysine.

Adenosine Diphosphate↗
PubMed1985

A possible adenine nucleotide storage form in normal and ischaemic rat heart.

Perfusion of Langendorff rat hearts with [14C]adenosine yields an acid-insoluble, radioactive product whose concentration falls during ischaemia. The properties of the substance show that it is a polyribonucleotide. It is suggested that it may be mitochondrial poly A acting as a storage form of adenine nucleotides.

Adenine Nucleotides↗
PubMed1985

Further studies on the presumed adenine nucleotide storage compound of rat heart.

Further studies on the acid-precipitable radioactive substance formed during perfusion of Langendorff rat hearts with [14C]adenosine have shown that very brief (30 s) ischaemia causes a sudden rise (20-35%) in its level in the tissue which is followed by the steady fall we have previously described. Analysis of the products of alkaline hydrolysis of this compound shows that at least 96% of the radioactivity appears in the form of a mixture of 2'- and 3'-AMP as would be expected for RNA while its relatively high resistance to dilute alkali suggests that it is poly A. Subcellular localization studies indicate that radioactivity enters all compartments of the cell, with maximum label in the nucleus. However, a significant proportion is present in the mitochondria and may be poly A acting as the mitochondrial storage form of adenine nucleotides whose existence we have proposed.

Adenine Nucleotides↗
PubMed1984

Photoreactivation in pigmented and non-pigmented extreme halophiles.

The sensitivity to ultraviolet radiation (254 nm) and the photoreactivability of four pigmented and three colourless strains of the extremely halophilic bacteria Halobacterium cutirubrum and Halobacterium salinarium have been studied. The results with three pigmented/non-pigmented pairs show that the pigments play an accessory role in photoreactivation at low visible light intensities and confirm that they do not provide passive protection against ultraviolet light. Evidence is presented that photoreactivation plays an unexpected direct role in the resistance of extreme halophiles to ultraviolet radiation and that colourless mutants of H. cutirubrum NRC 34001 only arise in cultures that have been both ultraviolet-irradiated and photoreactivated. None of these extreme halophiles is capable of excision repair of ultraviolet damage to DNA.

DNA Repair↗