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Biomedical subjects

S R Bawa

Publications and source records attributed to S R Bawa.

At least 37 records · Page 2Linked to original sources
PubMed1976

Effect of gamma-irradiation on cholesterol of chicken brain.

Cholesterol in chicken brain has been determined after head irradiation with 60Co gamma rays. The brain of five-week-old white Leghorn chickens, irradiated with 1200 R showed appreciable decrease in its cholesterol content after two and five days, and a slight increase after seven days of irradiation. But the cholesterol content after seven days of irradiation was still less than the control values. However, an insignificant increase in brain cholesterol (than control) was observed after 14 days of irradiation. Nine to ten weeks old Rhode Island Red chickens exposed to 4000 R head gamma-irradiation exhibited a similar effect in cholesterol content of the brain.

Animals↗
PubMed1975

Radiation effects on rat testes. V. Studies on lysosomal enzymes (acid phosphatase and acid DNAse) and their physiological significance following partial body gamma-irradiation.

Acid phosphatase is present in the nucleus and cytoplasm of cells in the seminiferous tubules and the interstitium of rat testes. The effect of irradiation on acid phosphatase is dependent on the environmental temperature and the dose of irradiation. It appears that initial rise in the enzyme at a low radiation dose and a high environmental temperature or at a high dose and low temperature is associated with a lysosomal breakdown of the germinal cells of the testes. A decrease in acid phosphatase in the advanced stages of radiation injury is a secondary radiation effect which may lead to decreased metabolic synthesis of phosphate esters owing to the unavailability of orthophosphate in the testicular tubules. The reduced acid phosphatase activity can be detected in the seminiferous tubules, suggesting that the enzyme activity is related to the state of the germ cell population. An initial increase in acid phosphatase is matched by an initial rise in acid DNAse within hours of irradiation, further suggesting that there is radiation interaction with the cells of the germinal epithelium. The enhanced activity of DNAse following a 2nd week of irradiation at 2000 R confirms the phagocytic activity of the non-germinal cells.

Acid Phosphatase↗
PubMed1975

Effect of malathion and radiation separately and jointly upon rat enzymes in vivo.

The effect of malathion (50 mg/kg) and radiation (900R) separately and jointly upon phosphatases and succinic dehydrogenase has been studied in female albino rats. Malathion and radiation when given separately, at the dose levels used in this study, appear to have no effect on acid and alkaline phosphatase of kidney, heart and brain. In preirradiated rats given malathion a significant decrease in phosphatases was observed in kidney and brain tissue after as little as 2 h and the values persisted for up to 24 h. No significant change was observed in heart tissue. At the dose level of 50 mg/kg of malathion, no significant change in succinic dehydrogenase was observed; however, radiation caused a significant increase in succinic dehydrogenase of brain and kidney tissue. In preirradiated rats given malathion the effect appeared to be enhanced in time to a certain degree. One could therefore speculate that simple non-specific stress caused by malathion adds to a similar effort of radiation by reducing phosphatases and enhancing the succinic dehydrogenase enzyme.

Acid Phosphatase↗
PubMed1975

Radiation effects on rat testes. VII. Alterations in nucleic acids and P-32 incorporation after partial body gamma-irradiation.

Effects of partial body gamma irradiation have been studied on rat testis at lethal (2000 R) and sublethal (720 R) doses. Radiation produced a progressive decline in DNA and RNA content of testis for first 15 days at both lethal and sublethal doses, followed by recovery as evidenced up to 74 days without any evidence for recovery of spermatogenesis. The incorporation of P-32 into nucleic acids was also low as compared to normal rats on day 8 postirradiation. Subsequently there was a tendency for the enhanced incorporation of P-32 in nucleic acid fractions. The P-32 nucleic acids specific activities were higher on 74th day in radiated rats than in normal controls. Enhanced incorporation of P-32 in nucleic acids and phospholipid fractions after 15 days of irradiation indicates greater synthetic activity of testicular interstitium rather than in recovery of germ cells.

Animals↗
PubMed1975

Radiation effects on rat testes. VIII. Kinetic properties of hydrolases following partial body gamma irradiation of rats.

Kinetic properties such as Michaelis constant (Km), maximum velocity (Vmax), temperature coefficient (Q10) and energy of activation (Ea) for hydrolysis of adenosine-5'-phosphate at pH 9.5 and sodium pyrophosphate at pH 8.35 by normal and radiated testes supernatants have been described. Kinetic parameters are related to respective phosphohydrolases (phosphatases). (1) Km values for 5'nucleotidase and inorganic pyrophosphatase of normal testis were determined as 1.25 X 10(-3)M and 0.81 X 10(-3)M respectively; (II) Vmax correspond to 318 mug P/15 min and 430 mug P/15 min for 100 mg tissue respectively; (III) Q10 for 5 nucleotidase is 1.7 and for inorganic pyrophosphatase is 4.2 at a temperature 10-30degreesC; (IV) Ea for hydrolysis of AMP and sodium pyrophosphate were calculated by Arrhenius plots as 17000 and 9000 cal/mol. (V) Km values for irradiated enzymes are similar to the control values suggesting that the binding capacities of these enzymes with their substrates remain unaffected after radiation; (VI) Vmax for radiated enzymes correspond to a value of 500 mug P/100 mg tissue/15 min for 5'nucleotidase and 118 mug P/100 mug tissue/15 min for inorganic pyrophosphatase; (VII) 110 for 5'nucleotidase is 2.2 and inorganic pyrophosphatase 1.16 at 10-30degreesC; (VIII) Ea for irradiated 5'nucleotidase is comparable to those of normal rats whereas for inorganic pyrophosphatase Ea is moderately declined. The observed changes have been related to the different types of metabolic activity in germinal and nongerminal cells of testes.

Adenosine Monophosphate↗
PubMed1975

Radiation effects on rat testes. IX. Studies on oxidative enzymes after partial body gamma irradiation.

Oxidative enzymes in the rat testes have been studied after gamma irradiation. The role of these enzymes in relation to spermatogenesis and steroidogenesis after radiation injury to testis has been discussed. Loss of succinic dehydrogenase and sorbitol dehydrogenase reflects the losts of germ cell population. Malic enzyme and malic dehydrogenase seem to the related to the deficiency of steroid hormones, whereas increase in glucose-6-phosphate dehydrogenase and NADP isocitric dehydrogenase is due to secondary stimulation of pituitary.

Animals↗