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Biomedical subjects

R Assan

Publications and source records attributed to R Assan.

At least 145 records · Page 8Linked to original sources
PubMed1979

Fuel metabolism in fasted newborn rabbits.

Newborn rabbits delivered by Caesarean section at term were fasted for 72 h at 36 degrees C. Despite the abrupt interruption of maternal supply of energy substrates, glycaemia remains stable for 4 h after birth. This can be related to glucose production via rapid liver glycogenolysis; however, indirect evidence suggests that gluconeogenesis could also contribute to glucose production during this period. There is a selective decrease in the concentrations of gluconeogenic substrates and a suitable hormonal environment for gluconeogenesis as decreased insulin and increased glucagon concentration just after birth. The relative hypoglycaemia which develops after 6 h of life (2.6 mM at 72 h), despite high blood concentrations of non-esterified fatty acids and ketone bodies is not due to a deficient gluconeogenesis per se, as injection of gluconeogenic substrates to 72 h fasted newborns produces a three-fold increase in plasma glucose concentration. It is suggested that this relative hypoglycaemia is secondary to limited gluconeogenic substrate availability in the form of low circulting concentrations of gluconeogenic amino acids.

Amino Acids↗
PubMed1978

[Functional inhibition of isolated pancreatic cells, new technic for the detection of macrophage cytotoxicity].

It is usually accepted that macrophages "activated" by lymphokines may be found cytotoxic against tumoral target cells but show no detectable cytotoxicity in in vitro tests using normal non tumoral cells as target cells. These data have been obtained mainly with the chromium-release test. The present paper describes a new test using normal isolated pancreatic cells as target cells and evaluating the effect of activated or non-activated macrophages on the insulin secretion response to glucose stimulation. The results show a striking decrease in this response following an 18-hr incubation of pancreatic islet cells with activated macrophages, as compared to that of the same cells incubated with control macrophages. This is clear evidence that activated macrophages may alter normal cells and suggests that their cytotoxic properties are not restricted to tumoral target cells.

Animals↗
PubMed1978

Regulation of phosphoenolpyruvate carboxykinase and fatty acid synthetase in brown fat of suckling rats.

Infant rats were injected with prednisolone (0.5-5 mg/100 g wt). This caused phosphoenolpyruvate carboxykinase (PEPCK) activity to rise in liver and to decrease in brown fat. Fatty acid synthetase (FAS) activity remained unchanged in liver but increased in brown fat. A single injection of prednisolone caused hepatic PEPCK activity to remain elevated for at least 7 days. Brown fat FAS also remained high for that period. However, brown fat PEPK activity returned to normal on the third day after the injection. A single injection of prednisolone or cortisone to 5-day-old rats caused a transient elevation of the blood level of insulin and a prolonged decrease in that of growth hormone. No effect on the level of glucagon was noted. Injections of insulin had effects similar to those of prednisolone, i.e. a rise in hepatic and a fall in brown fat PEPCK. Using antibodies prepared to hepatic PEPCK it was shown that the observed changes were due to changes in the rate of synthesis of the enzyme. Using actinomycin D indirect evidence was obtained that changes in FAS activity of brown fat were also due to changes in the synthetic rate.

Adipose Tissue, Brown↗
PubMed1977

[Hypoglycemia in 2 patients treated with perhexiline maleate].

Hypoglycaemia occurred in two patients treated with perhexiline maleate. The responsibility of the medication is discussed in each case. Blood insulin levels were increased. Blood perhexiline levels decreased very rapidly in the first patient, though much more slowly in the second.

Aged↗
PubMed1977

Control of blood cholesterol levels in suckling and weanling rats.

The high blood cholesterol and glucagon levels of suckling rats can be rapidly decreased within 24 hours by prematurely weaning rats to a high carbohydrate diet on day 18. The fall in the cholesterol level is much smaller if rats are starved for 24 hours. This decrease can partly be inhibited by injections of glucagon. The only factor so far found to decrease blood cholesterol levels in suckling rats was starvation. Insulin, which slightly but significantly, depressed the level in 40 day old rats, increased it in suckling ones, as does prednisolone. It is concluded that blood cholesterol levels are more easily manipulated in suckling rats than in older rats, and that this is probably related to a different hormonal balance.

Animals↗