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Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Clostridium purinolyticum decomposed uric acid via pyrimidine derivatives under selenium starvation conditions. Products were acetate, formate, glycine, ammonia, and CO2. 4,5-Diaminouracil could be identified as an intermediate after converting the labile substance into 6,7-dimethyllumazine. The breakdown of uric acid was inhibited by EDTA. High-pressure liquid chromatography methods have been developed for the simultaneous determination of uric acid, 4,5-diaminouracil, and 6,7-dimethyllumazine. The significance of the new pathway is discussed.
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PMID:Anaerobic degradation of uric acid via pyrimidine derivatives by selenium-starved cells of Clostridium purinolyticum. 680 63

Male Sprague-Dawley rats and male B6C3F1 mice excreted 5-15% of a tracer dose of [14C]trichloroethylene as 14CO2 within 24 h after ip injection of a single dose in a corn-oil vehicle. The proportion of the dose excreted as CO2 was greater in mice than in rats, but increased in the rats after starvation or pretreatment with phenobarbital. As the dose was increased toward the LD50 level, the proportion excreted as 14CO2 decreased slightly, but this was largely due to increased loss of unchanged trichloroethylene. The excretion of 14CO2 was thus correlated with the expected level of microsomal metabolism of trichloroethylene to an electrophilic intermediate capable of binding to glutathione or macromolecules. Liver protein labeling was observed to be relatively high (10,000-23,000 cpm/mg in the mouse), while DNA labeling was consistently observed to be very low, not allowing identification of any adducts by high-performance liquid chromatography (HPLC). Also, no effect on DNA fragmentation was seen by alkaline sucrose gradient centrifugation after injection of an LD50 dose of trichloroethylene. The ability of trichloroethylene to interact with DNA in vivo was thus observed to be very slight.
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PMID:Metabolism of [14C]trichloroethylene to 14CO2 and interaction of a metabolite with liver DNA in rats and mice. 681 65

The metabolic regulation of alpha-ketoisocaproic acid was studied in fetal brain from rats. Starvation of the mother for days 18-20 did not alter CO2 evolution from alpha-ketoisocaproic acid in fetal brain slices but significantly diminished the incorporation of the branched-chain keto acids into leucine. When fetal brain slices from starved mothers were exposed to graded concentrations of labeled alpha-ketoisocaproic acid (0.05-2.5 mM), over 70% of the labeled products were consistently represented by leucine and less than 30% by CO2. Both beta-hydroxybutyrate and pyruvate, alone and in combination, diminished the amount of 14CO2 that evolved from alpha-ketoisocaproic acid-1-14C, but had no effect on the conversion of the keto acid to labeled leucine. It is concluded that exogenous alpha-ketoisocaproic acid is preferentially converted to leucine by fetal brain slices independent of the nutritional state of the mother. During maternal starvation, beta-hydroxybutyrate, by restraining irreversible decarboxylation of alpha-ketoisocaproic acid, could act to salvage the keto acid for conversion to leucine. Thus alpha-ketoisocaproic acid metabolism in the fetal brain may be regulated in part by altered metabolic functions in this structure and in part by changing components in circulating fuel mixtures reaching the fetus from the starved mother.
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PMID:Fetal fuels VI. Metabolism of alpha-ketoisocaproic acid in fetal rat brain. 684 58

When Candida albicans is grown at 25 degrees C in suspension in defined medium, cells accumulate at stationary phase as singlets in G1 of the deoxyribonucleic acid replication cycle and acquire the capacity to form mycelia. When cells were removed from a stationary-phase culture and a low concentration of fresh cells was inoculated into the cell-free, stationary-phase medium, the fresh cells grew to approximately the same cell density as the original culture. We demonstrated that in the accompanying decrease in pH, nor due to a depletion of O2, an accumulation of CO2, a physical crowding effect, or accumulation of the putative autoinhibitors tryptophol and 2-phenylethyl alcohol. Rather, cells stop multiplying at stationary phase due to the depletion of zinc from the culture medium. The manipulation of cultures with glassware to remove stationary-phase cells and to add fresh cells led to the addition of zinc to the medium and hence a new round of culture growth. The same manipulations with plasticware did not result in zinc supplementation and hence in now new round of culture growth. When cells enter stationary phase in excess zinc, they do not accumulate as singlets; rather, they accumulate as budded cells. When these cells were induced to form mycelia, they did so in half the time it took zinc-starved cells. The usefulness of employing zinc starvation as a method for obtaining a uniform stationary-phase phenotype and for synchronizing induced mycelium or bud formation is discussed.
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PMID:Zinc and regulation of growth and phenotype in the infectious yeast Candida albicans. 701 88

Slices of fetal rat kidney were incubated for 90 min at 37 degrees C in Krebs phosphate buffer containing [14C]glucose. Glucose uptake did not change significantly with age, but the 14CO2 evolved from [14C]-glucose dropped, and the lactate concentration at the end of incubation rose. The increasing development of the medulla during gestation was believed to be responsible for this. Higher glucose uptake and lower [14C]glucose incorporation into CO2 was observed in whole fetal slices compared to cortical slices from adult kidney, incubated following the same procedure. These results might be due to the smaller number of functionally differentiated nephrons present in fetal compared to adult kidney. Competition between glucose and lactate, normally found at high concentrations in fetal blood, and between glucose and beta-hydroxybutyrate, known to increase in circumstances such as starvation in the mother, showed a decrease in the 14CO2 evolved from [14C]glucose. This suggests that both these substrates might be oxidized by fetal kidney. This was confirmed by experiments in which lactate or beta-hydroxybutyrate replaced glucose in the incubation medium. Further, both these substrates seemed to be preferential fuels for oxidation compared to glucose, and their possible role in saving glucose is discussed.
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PMID:Oxidative metabolism in fetal rat kidney during late gestation. 717 19

The utilisation (conversion to CO2 and/or glucose) of a series of amino acids by isolated trout hepatocytes was investigated and compared to the utilisation of lactate and palmitate. In fed fish, several amino acids (alanine, serine, asparagine and glycine) and lactate produced CO2 at considerably higher rates than palmitate. During starvation plus exercise, the rate of CO2 production from palmitate increased while that from lactate and most of the amino acids decreased. Gluconeogenesis from amino acids in fed fish was lower than from lactate. Serine and asparagine were the most effective substrates; alanine gave lower rates of incorporation. During prolonged starvation plus exercise, the rates of gluconeogenesis from amino acids increased twofold and, simultaneously, there was a corresponding increase in phosphoenolpyruvate carboxykinase activity in liver. It is concluded that several amino acids (dietary or released from muscle protein) are potentially major oxidative substrates in trout. In addition, amino acids appear to have the capability to maintain supplies of glucose during a period of prolonged starvation and exercise. No evidence could be found to support the contention that alanine is the most important glucogenic amino acid.
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PMID:Amino acid utilisation in isolated hepatocytes from rainbow trout. 720 13

Using radioactive tracers, the effect of n-alkanes with a varying length--C16-C25--of the carbon chain on the rate of yeast growth and the ratio of major chemicals in their biomass was studied. The change in the level of n-alkanes accumulated by the yeast during carbon starvation was determined. No differences in the rate of metabolization of 1-14C-octadecane, 1,2-3H-hexadecane, and 13-14C-pentacosane were found. During 3 hour incubation the cell losses of C25, C18 and C16 amounted to 35.0, 33.0 and 38.1 microgram alkane/mg yeast, respectively. The intensity of yeast growth in the accumulative culture on dispersed n-alkanes with different molecular weights was similar. The specific formation of CO2 during the lag-phase by the yeast cultivated C18 was larger than on C23 or C25. The lipid content in the yeast grown on C18 was 3 times greater than in those grown on C22. The difference was made by an increased content of triglycerides and waxes.
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PMID:[Assimilation of n-alkanes with a varying length of the carbon chain by the yeast Candida guilliermondii]. 738 5

Changes in placental lipid content in rats at the 15th and 20th days of pregnancy were investigates. It was found that progress of gestation is accompanied by a significant increase in triglycerides per mg placental DNA. Maternal starvation caused additional increase in the placental triglyceride content. By incubation with 14C-oleic acid, it was shown that placenta at term possesses an increased capacity to esterify fatty acids at a wide range of medium oleic acid concentrations. Increase in free fatty acid concentration caused a linear increase of their incorporation into placental lipids. Oxidation of oleic acid into CO2 was also increased with the duration of gestation, but to a lesser degree and over a narrower range of concentration than esterification, suggesting an increased channelling of fatty acids into glycerides.
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PMID:Lipid deposition and metabolism in rat placenta during gestation. 745 90

The occurrence of a postoperative complication represents an additional stress factor for patients and leads in many cases rapidly to a malnutrition status. Thus a nutritional support is required as soon as the foreseeable duration of starvation has a longer duration than one week. Considering its lower risk of septic complications and lower cost, enteral feeding should be initiated as soon as possible. Appraisal of caloric needs with standard formulas often leads to inappropriate nutritional management. Therefore the requirements should be assessed by indirect calorimetry if available. Nutritional support is a part of the management of a postoperative septic patient. It must be initiated when initial phase of haemodynamic instability is amended. Branched chain amino acids, medium chain triglycerides and other specific nutrients have failed to demonstrate a real clinical beneficial effect. In case of acute respiratory failure, nutritional support must be cautious with regard to caloric load, as carbohydrates may increase CO2 production and lipids may worsen hypoxaemia. In case of postoperative acute renal failure, nutritional management is facilitated by continuous haemofiltration techniques allowing an unlimited nutrient intake. Solutions containing only essential amino acids are not recommended. During severe acute pancreatitis, enteral feeding is indicated when ileus does not permit the use of the intestinal tract. Jejunal access must be preferred to stomach or duodenum. Lipid emulsions can be used safely if serum triglyceride concentrations remain below 4 g.L-1 during infusion and below 2 g.L-1 between infusions.
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PMID:[Effect of postoperative complications on nutritional status: therapeutic consequences]. 748 37

Estradiol treatment of starving immature rainbow trout dramatically alters the metabolic performance of isolated hepatocytes. One and two weeks postimplantation with estradiol, the rate of de novo glucose synthesis from [14C]alanine is reduced fourfold from 0.4 mumol/g/hr to 0.1 mumol/g/hr, compared with vehicle-injected control fish. After 6 weeks, the rate of glucose production on a gram wet weight basis is identical in both treatment groups, but significantly larger (by 80%) in the estradiol-treated group than in the controls, if expressed normalized to the hepatosomatic index (HSI). Estradiol treatment caused preferential partitioning of alanine carbon into oxidative pathways away from gluconeogenesis, indicated by a significantly lower ratio of glucose production over CO2 production in hepatocytes isolated from estradiol-treated animals. Incorporation of [14C]alanine into acid-precipitable protein is significantly larger in the estradiol-treated group after 2 weeks, and also after 6 weeks, when normalized to the HSI, indicating that part of the protein synthesized in the estradiol-treated groups is vitellogenin. No differences were detected between estradiol-treated animals and control animals in the activities of enzymes associated with gluconeogenesis [phosphoenolpyruvate carboxykinase, fructose 1,6-bisphosphatase (FBPase)] and amino acid metabolism (alanine and aspartate aminotransferases) in the time course investigated (expressed on a wet weight basis). Activities normalized to the HSI are higher in fish implanted with estradiol compared with controls at 2 and 6 weeks. In keeping with the increased potential of hepatocytes for CO2 production from alanine, estradiol treatment doubled and tripled the maximum activity of pyruvate kinase 1 and 2 weeks postimplantation, respectively. Fish were fasted to avoid erratic feeding due to treatments. Superimposed on estradiol actions are effects of starvation: a fourfold increase in the rate of gluconeogenesis, a threefold increase in oxidative flux, and a fivefold increase in the activity of FBPase--all normalized to hepatocyte weight.
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PMID:Gluconeogenesis in hepatocytes of immature rainbow trout (Oncorhynchus mykiss): control by estradiol. 767 84


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