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

Rat liver glucose 6-phosphate dehydrogenase (G6PD) and malic enzyme (ME) activities were increased by starvation-refeeding to levels above those found in rats fed ad libitum. The increases in enzyme activities above ad libitum-fed levels were prevented by 8-azaguanine and 6-azauridine, but not by 2-azauridine. Blood insulin levels were not affected at the time studied. Two aza analogs, 8-azaadenine and 5-azacytidine, proved to be too toxic in this type of studies. Since 8-azahypoxanthine, 8-azaxanthine and 5-azauracil were neither effective in preventing the enzyme overshoot, nor toxic to the animals, it was concluded that the toxiciyty to the animals of 8-azaadenine and 5-azacytidine is due to the compounds themselves rather than to the breakdown products.
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PMID:Effect of aza-substituted nucleotides on the starve-refeed response of rats. 4 59

Plasma-secretin levels were measured by radioimmunoassay during a 72-hour starvation period in nine healthy subjects. Immunoreactive secretin (I.R.S.) levels rose dramatically during starvation. The rises were several orders of magnitude greater than those after intraduodenal acid. The classic concept that the major function of secretin is the control of the exocrine pancreas is challenged by these results. The findings suggest that secretin is a hormone of importance during starvation, and its role in starvation may be related to its lipolytic properties.
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PMID:Secretin: A new role for an old hormone. 5 60

The bleomycins are antitumor agents composed of various cationic amides of a common inactive bleomycinic acid. At 1 mug/ml at 37 degrees, the naturally occurring spermidine derivative of bleomycin (A5) was far more lethal to Escherichia coli than were several other bleomycins tested. An exponential loss of viability was produced for 2 hr in various strains of E. coli growing in a synthetic medium. In the stringent E. coli, strain 15 TAU (thymine-arginine-uracil) rel A+ (arginine), withholding thymine did not affect the rate of killing. However, uracil starvation completely blocked killing by the antibiotic. Arginine deprival partially inhibited bleomycin killing in the stringent cell but had little effect on the lethality of the antibiotic in a relaxed isogenic strain actively synthesizing RNA. Similar results were obtained with another isogenic pair, stringent CP78 and relaxed CP79. Thus, the lethality of the antitumor agent, bleomycin, which is reported to produce breaks in bacterial and animal cell DNA in vivo and in vitro appeared totally dependent on RNA synthesis in E. coli. Nevertheless, chloramphenicol, which blocks protein synthesis and relaxes RNA synthesis in the stringent strains, also significantly inhibited the lethal action of the antibiotic, reducing the exponential rate of killing.
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PMID:Synthesis and the lethality of bleomycin in bacteria. 5 23

Acid phosphatase activity is demonstrated employing p-nitrophenyl phosphate as substrate and lead acetate as coupler. The fine structural localization of the enzyme in starved planarian tissues is described. The method is used to pin-point starvation - induced acid phosphatase activity in relation to autophagy and crinophagy in the gland cells; autophagy, autolysis and cell death in parenchymal and gastrodermal cells and basement membrane lysis. Attention is also payed to the demonstration of muscle lysis. The histochemical implications of the method are discussed.
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PMID:Use of the p-nitrophenyl phosphate method for the demonstration of acid phosphatase during starvation and cell autolysis in the planarian Polycelis tenuis Iijima. 5 22

The hypothesis is advanced that starvation suppresses and refeeding activates certain infections as an essential part of an ecological balance between man, his animals, and his environment. During famine, then, man fails to thrive, but his ultimate extinction is prevented in part by the parallel decline in fecundity of his "micropredators". In times of plenty the parallel increase in the same predators is a check against his excessive multiplication.
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PMID:Starvation suppression and refeeding activation of infection. An ecological necessity? 6 55

Changes of the metabolic pool constitutents of Monosporium olivaceum -- a mould capable of steroid hydroxylation were examined. The experiments were carried during growth and starvation of the microorganism. The highest activity of the 11alpha-hydroxylase was observed in the mycelium which contained the lowest level of free amino acids, glucose, and mannitol. It is suggested that the inhibition of biosynthetic processes and the decrease of the respiration rate, the activity of the NAD(P)H regenerating systems maintained, provide the optimal physiological conditions for the activity of the steroid hydroxylases.
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PMID:Changes in the cellular content of the pool constituents of Monosporium olivaceum -- a steroid hydroxylating mould. 6 6

The cytotoxic potential of heterologous rabbit antibody directed against mouse serum albumin (MSA) and alpha-fetoprotein (AFP) was investigated in vitro with a cell line (Hepa) derived from the mouse hepatoma BW7756. Anti-AFP in the presence of complement could kill Hepa cells at concentrations of anti-MSA that were virtually nontoxic. The specificity of the anti-AFP was defined by demonstrating that Hepa cell toxicity was dependent upon and paralleled the secretion of AFP in synchronized cultures. Furthermore, neither antiserum could be shown to be significantly toxic to mouse neuroblastoma cells (Neuro-2A). Immunoglobulin purified from pools of antisera was also highly effective in producing cytotoxicity even in a complement-free system. This reaction proceeded more slowly, requiring nearly 48 hr to reach maximum effect in comparison to the 12 hr for complement-mediated toxicity. MSA and AFP are secreted during different phases of the cell cycle. In cultures arrested by isoleucine starvation, labeled AFP appears in the medium 10 hr after release of the blockade in association with S phase. The appearance of labeled MSA is delayed until the first mitosis. Cytotoxic effects of anti-AFP parallel the secretion of AFP in synchronous cultures. Both antisera could be inhibitory to the secretion and synthesis of the proteins of their antigenic specificity. MSA synthesis was more susceptible to this inhibition than was AFP synthesis. The significance of this phenomenon and its association with the differential cytotoxicity of the antiserum are discussed.
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PMID:The influence of antisera specific for alpha-fetoprotein and mouse serum albumin on the viability and protein synthesis of cultured mouse hepatoma cells. 6 16

Proteolysis rates in vivo were measured in Escherichia coli cultures during treatment with dihydrostreptomycin and under various other conditions. Dihydrostreptomycin treatment caused an increase in the proteolysis rate, compared to untreated controls. The proteolytic system in vivo responsible for the elevated proteolysis in the early stages of dihydrostreptomycin treatment, or that during canavanine and puromycin treatment, were not inhibited by addition of phenylmethanesulphonyl fluoride. This agent did inhibit proteolysis rates in cultures whose growth was inhibited by starvation, or had been completely stopped by dihydrostreptomycin. It seems, therefore, that the extremely high proteolysis rates in cultures at this stage of dihydrostreptomycin treatment were due to the action of two protease systems: the one concerned with the breakdown of abnormal proteins, and the other concerned with normal protein turnover and active during a non-specific decline of growth. The proteolytic rate at complete growth inhibition brought about by dihydrostreptomycin was intermediate between those induced by canavanine and puromycin at the same stage of treatment. This indicated a similar hierarchy in the extent and nature of abnormality in the proteins synthesized under these conditions. The relationship between the abnormality of proteins induced by dihydrostreptomycin and the importance of this in the antibiotic mechanism is discussed.
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PMID:An investigation of mistranslation in vivo induced by streptomycin by an examination of the susceptibility of abnormal proteins to degradation. 6 37

1. The concentrations of serum protein albumin, prealbumin and transferrin were determined in twenty-eight cases of protein-energy malnutrition (PEM) with infection, together with the levels of serum proteinase inhibitors (PI), alpha1-antitrypsin (AT), alpha1-antichymotrypsin (Ach), alpha2-macroglobulin (alpha2M) and inter-alpha-trypsin inhibitor (IalphaI). 2. Albumin, prealbumin and transferrin concentrations, as well as the levels of PI, IalphaI and alpha2M were found to be lower in cases of PEM associated with infection than the corresponding values for a group of healthy Thai preschool children and a group of newborn Thai children, but despite starvation AT and Ach values generally were increased. 3. The results provide support for the hypothesis that PI, especially AT and Ach might limit the synthesis of albumin, prealbumin and transferrin in PEM associated with infection, via the inhibition of the mobilization of body's own protein.
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PMID:Serum proteinase inhibitors and other serum proteins in protein-energy malnutrition. 7 Feb 17

After an initial decrease, the specific activity of Physarum polycephalum acid phosphomonoesterase increases during the growth of the organism in an axenic medium. This increase is independent of the inorganic phosphate concentration in the culture medium. The specific activity of inorganic alkaline pyrophosphatase remains constant during the growth and is not modified by a high extracellular concentration of orthophosphate. During starvation in a non nutritive saline medium, the increase of acid phosphatase activity is immediate whereas pyrophosphatase activity remnins constant.
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PMID:Studies on the activities of an acid phosphomonoesterase and an alkaline pyrophosphatase during the growth of Physarum polycephalum. 7 Oct 89


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