[South American blastomycosis: report of a case with ocular lesion].
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Biomedical subjects
Publications and source records attributed to R Curi.
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The functions of glutamine are many and include, substrate for protein synthesis, anabolic precursor for muscle growth, acid-base balance in the kidney, substrate for ureogenesis in the liver, substrate for hepatic and renal gluconeogenesis, an oxidative fuel for intestine and cells of the immune system, inter-organ nitrogen transport, precursor for neurotransmitter synthesis, precursor for nucleotide and nucleic acid synthesis and precursor for glutathione production. In the present review information on the mechanism of glutamine action is presented. This amino acid has been shown to regulate the expression of several genes (such as p47phox, p22phox, gp91phox, alpha-actin and fibronectin) and activate several proteins (such as ASK1, c-myc, c-jun and p70s6k).
The acute effects of isolated and combined L-alanine (L-Ala) and L-glutamine (L-Gln) on liver gluconeogenesis, ureagenesis and glycaemic recovery during short-term insulin-induced hypoglycaemia (IIH) were investigated. For this purpose, 24-h fasted rats that received intraperitoneal injection of regular insulin (1.0 U/Kg) were investigated. The control group (COG group) were represented by rats which received saline. The studies were performed 30 min after insulin (IIH group) or saline (COG group) injection. Livers from IIH and COG groups were perfused with basal or saturating levels of L-Ala, L-Gln or L-Gln + L-Ala (L-G + L-A). The production of glucose, urea, L-lactate and pyruvate in livers from IIH and COG group were markedly increased (p < 0.001) when perfused with saturating levels of L-Ala, L-Gln or L-G + L-A compared with basal levels of the same substrates. In addition, livers from IIH rats showed greater ability in producing glucose and urea from saturating levels of L-Ala compared with L-Gln or L-G + L-A. In agreement with these results, the oral administration of L-Ala (100 mg/kg) promoted better glycaemic recovery than L-Gln (100 mg/kg) or the combination of L-G (50 mg/kg) + L-A (50 mg/kg). It can be concluded that L-Ala, but not L-Gln or L-G + L-A could help glycaemic recovery by a mechanism mediated, partly at least, by the increased gluconeogenic and ureagenic efficiency of L-Ala.
We investigated the effect of a meal feeding schedule (MFS) on food intake, hepatic glycogen synthesis, hepatic capacity to produce glucose and glycemia in rats. The MFS comprised free access to food for a 2-hour period daily at a fixed mealtime (8.00-10.00 a.m.) for 13 days. The control group was composed of rats with free access to food from day 1 to 12, which were then starved for 22 h, refed with a single meal at 8.00-10.00 a.m. and starved again for another 22 h. All experiments were performed at the meal time (i.e. 8.00 a.m.). The MFS group exhibited increased food intake and higher glycogen synthase activity. Since gluconeogenesis from L-glutamine or L-alanine was not affected by MFS, we conclude that the increased food intake and higher glycogen synthase activity contributed to the better glucose maintenance showed by MFS rats at the fixed meal time.
Lipids, either as membrane components or as fuel, are important nutrients that can affect insulin secretion. The aim of this study was to establish the maximum tolerable amount of fat present in the diet, which does not induce significant alteration in the process of insulin secretion. For that, just-weaned male albino rats (70-90 g body weight) were fed during 6 weeks with diets for growing rodents containing 7% fat (A Group) as recommended by the American Institute of Nutrition-AIN. Two other groups in which the fat content of the diet was increased to reach 10% (B Group) or 13% (C Group) were also included. Insulin release, 86Rb+ and 45Ca2+ Fractional Outflow Rate (FOR) during the process of glucose-induced insulin secretion was determined in perfused islets isolated from these animals. No statistical differences in these parameters were detected between A and B rats. However, in the C group, a lower 86Rb+ FOR was found during the whole experiment and a poor insulin secretory response to glucose stimulus was observed. These results led us to postulate that the maximal limiting amount of total lipids present in the diet that does not impair the process of glucose-induced insulin secretion is 10%. These findings authorize future studies on the interference of different dietary lipid sources, in a content 43% more elevated than that recommended (10% against 7%), on the mechanisms of insulin secretion.
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Protein and electrolyte disturbances in hepatic and muscle tissues are related to trauma, sepsis, or short term starvation or semistarvation. The consequences of a prolonged semistarvation are poorly understood. For five weeks, male adult rats were offered 50% of the diet until they had a weight loss of 40%, after which protein and electrolyte (Ca++, Mg++, Zn++, Na+, K+) changes in the liver and soleus and extensorum digitorum longus muscles were analyzed. There was a significant weight loss after 5 weeks of semistarvation. Hepatic protein and serum albumin were not changed, but the authors observed a significant muscle protein depletion. A fall in Zn++ levels in the blood was accompanied by a rise in muscle and liver concentrations. The rise in Ca++ and Mg++ concentration in blood and in the muscles might be related to the enhanced proteolysis. Results suggest that the early changes of protein and electrolyte metabolism at tissue level with semistarvation impair muscular and hepatic functions as they delay adequate response to trauma and infection.