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

Though children with febrile convulsions only have seizures in the early stage of a febrile illness and not later, these seizures have been attributed to the fever. We studied the serum electrolyte and metabolite profiles in the later stage to see if there were fuel responses resulting in electrophysiological changes which prevented further seizure activity. On admission there was intracellular glucose starvation, as evidenced by increased ketones and lactate, and the possibility of the failure of some electrolyte pumps, as suggested by hyperuricaemia (energy crisis) and decreased serum Na+, Cl- and Ca2+. However, there was adaptive hyperglycemia and decreased serum K+. It seems likely that the hyperglycemia, induced the uptake of K+ by neurones, enabling their repolarization and hyperpolarization, which prevented further seizure activity, while Cl- influx short-circuited depolarizing currents produced by Na+ influx. Studies during recovery showed a gradual return of the metabolic and electrolyte aberrations to normality, suggesting that the provision of energy through adaptation to the stress, enabled recovery of the aforementioned pumps.
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PMID:Hyperpolarization and short-circuiting as mechanisms of seizure prevention following febrile convulsions. 277 93

Cell envelope composition and selected physiological traits of Vibrio parahaemolyticus were studied in regard to the Kanagawa phenomenon and growth conditions. Cell envelopes were prepared from cells cultured in Proteose Peptone-beef extract (Difco Laboratories, Detroit, Mich.) medium or filtered estuarine water. Protein, phospholipid, and lipopolysaccharide contents varied with culture conditions. The phospholipids present in the cell envelopes were identified as phosphatidylethanolamine, phosphatidylglycerol, and cardiolipin. Phosphatidylethanolamine decreased and phosphatidylglycerol increased in cells grown in estuarine water. Profiles of proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrated numerous protein species, with four to six predominant proteins ranging from 26,000 to 120,000 in molecular weight. The profile of V. parahaemolyticus cell envelope proteins was unique and might be useful in the identification of the organism. Alkaline phosphatase activity was slightly higher in Kanagawa-negative strains and was higher in cells grown in estuarine water than in cells grown in rich laboratory medium. The DNA levels in estuarine water-grown cells increased, while RNA levels and cell volume decreased. Bacteriophage sensitivity typing demonstrated a close intraspecies relationship. Results indicated that Kanagawa-positive and -negative strains were closely related, but they could be grouped separately and may have undergone starvation-related physiological changes when cultured in estuarine water.
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PMID:Comparison of Vibrio parahaemolyticus grown in estuarine water and rich medium. 278 69

Crithidia luciliae, a trypanosomatid protozoan readily grown in axenic cultures, was shown to possess low levels of a surface membrane-bound ectoenzyme capable of hydrolyzing both 3'-ribonucleotides and nucleic acids. The specific activities of this 3'-nucleotidase/nuclease, with both mononucleotide and nucleic acid substrates, were greatly enhanced when the protozoa were deprived of purines, an essential nutrient. The catalytic activities were exhibited by a polypeptide which migrated in sodium dodecyl sulfate-polyacrylamide gel electrophoresis with an Mr of 47,000. Starvation of these cells for inorganic phosphate (Pi), in media with or without purines, also led to an increase in the specific activity of the ectoenzyme compared to that of Pi- and purine-replete cells. In contrast, the level of enzyme activity was not increased when the protozoa were starved, under purine-replete conditions, for either arginine or hemin, two other essential nutrients. Cells starved simultaneously for either of the latter two nutrients and for purines also did not show increased levels of the 3'-nucleotidase/nuclease. The activation of the enzyme was also prevented by sodium arsenite, cycloheximide, actinomycin D, and tunicamycin indicating that the activation presumably required metabolic energy as well as new transcription, translation, and protein modification. The results demonstrate that the control of 3'-nucleotidase/nuclease expression is a regulated, adaptive response to growth-limiting levels of essential nutrients.
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PMID:Crithidia luciliae: factors affecting the expression of 3'-nucleotidase/nuclease activity. 283 57

We have analyzed the effects of the cAMP relay inhibitor, caffeine, and the receptor antagonist, adenosine, on the regulation of the cell-surface cAMP receptor in suspension-starved Dictyostelium discoideum cells by measuring ammonium sulfate-stabilized binding of [3-H]cAMP to intact cells. When cells were starved in fast (230 r.p.m.) shaken suspension in 10 mM Na+/5 mM K+ phosphate buffer, pH 6.5, plus 1 mM CaCl2 and 2.5 mM MgCl2, and assayed for specific cAMP binding, receptor accumulation peaked at approximately 6 hours, reaching a maximum of 1.5 pmol cAMP bound/10(7) cells (saturation binding). Neither caffeine nor adenosine inhibited the accumulation of cAMP receptors. Similar results were obtained in caffeine-treated, slow shaken (90 r.p.m.) suspension cultures. These results suggest that starvation alone is sufficient stimulus to induce the cAMP receptor. We have also tested the effects of different buffer ionic compositions on the accumulation of cAMP receptors. Elevation of the monovalent ion concentration to 30-40 mM was found to significantly inhibit the induction of cAMP receptors.
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PMID:The effect of caffeine, adenosine, and buffer ionic composition on the induction of cell-surface cAMP binding during starvation of Dictyostelium discoideum. 285 21

Diarrhea or respiratory infection constitutes the terminal illness in most starved children and adults. A major component of starvation diarrhea appears to be an organ-specific malnutrition of the inestinal epithelium, not bacterial overgrowth. Faced with an overburden of nutrients on refeeding, the intestine cannot salvage ions because its epithelium has insufficient energy to control absorption effectively. In many cases, patients have a worsening of diarrhea and die within the 1st few days of oral refeeding. Antibiotics are particularly detrimental in starvation because they prevent effective bacterial fermentation and thus production of substrates for mucosal growth and sodium absorption. Oral rehydration thereapy uses glucose to drive sodium absorption in the small intestine mucosa, but it provides little energy to the mucosa. Nutrition of the small bowel mucosa is promoted by increasing the vascular supply of amino acids. Once nutrition of the intestinal mucosa has been restored, absorption of orally supplied nutrients becomes efficient. Refeeding diets in starvation should have a relatively high content of ferementable complex polysaccharides and dietary fiber and smaller amounts of milk fats and glucose than are normally provided to severely malnourished children. The starved intestinal epithelium returns to functional capacity after 5-7 days. As a result of the therapeutic implications in severely malnourished children, it is essential that cases of infective diarrhea and starvational diarrhea be differentiated from each other.
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PMID:Metabolic basis of starvation diarrhoea: implications for treatment. 287 46

1. The perfused isolated head technique has been used to measure sodium arterial fluxes following direct transfer from fresh water to sea-water. 2. A starvation-related decrease in net sodium flux is reported. 3. Sexual maturation slackens the decrement of this net flux. 4. In starved fish, the cytological modifications of chloride cells following such a transfer are delayed. 5. This effect of starvation is discussed in terms of lamella sodium imperviousness.
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PMID:The effects of starvation and sexual maturation on Na+ transbranchial fluxes following direct transfer from fresh water to sea-water in rainbow trout (Salmo gairdneri). 288 46

1. The effect of starvation for 12 months on organo-somatic indices, glycogen, protein and water contents of several organs and the Na+/K+ ratio in muscle was studied in the South African clawed toad Xenopus laevis Daudin. 2. The liver- and ovary-somatic index were reduced by 30 and 70% of the initial value after 12 months. Fat bodies had disappeared after approximately 6 months of starvation. The indices of heart and kidney were not changed. 3. Glycogen concentration of the liver, ovaries and muscle were depleted nearly totally during the first half of the experimental time, whereas glycogen in the kidney seemed to be unaffected. 4. Protein concentration increased in the liver, decreased in the muscle and remained constant in the kidney. 5. Starvation caused an increase of the water concentration of the whole animal and different organs, especially at the end of the experiment. 6. The Na+/K+ ratio of the muscle increased significantly after 6 months of starvation and reached a maximum after 10 months.
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PMID:Long-term starvation in Xenopus laevis Daudin--II. Effects on several organs. 290 21

Oxygen consumption and Na+,K+-ATPase(EC 3.6.1.3)-dependent (ouabain-sensitive) and -independent respiration were measured for duodenal mucosa biopsies from 10-month-old sheep given two levels of digestible energy (DE) intake (7.6-7.7 and 14.8 MJ lucerne (Medicago sativa) pellets/d) and following 48 h of starvation. The mucosal biopsies were determined to be structurally intact and free of adherent bacteria on histological and scanning-electron-microscope examinations. The use of D-glucose as a substrate during incubations did not elevate (P greater than 0.05) the respiration indices of the biopsies over those measured during acetate incubations. Glucose uptake did not (P greater than 0.05) influence the Na+,K+-ATPase-dependent respiration of the mucosal biopsies. Na+,K+-ATPase-dependent respiration accounted for 50% of the total O2 consumption of the mucosal biopsies of sheep given the lower level of DE. Total O2 consumption of the duodenal mucosa was not (P greater than 0.05) increased when sheep were given the higher level of DE but Na+,K+-ATPase-dependent respiration of the mucosa was elevated (P less than 0.01) by 37% during this period. When sheep were starved for 48 h, total O2 consumption of the mucosal biopsies was not (P greater than 0.05) affected, however, Na+,K+-ATPase-dependent respiration of the biopsies dropped (P less than 0.01) by 45%. Na+,K+-ATPase-dependent respiration accounted for 61.3% of the O2 uptakes of mucosa from the sheep given the higher level of DE and 28.3% of the O2 uptake of mucosa from fasted sheep.
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PMID:Influence of feed intake and starvation on the magnitude of Na+,K+-ATPase(EC 3.6.1.3)-dependent respiration in duodenal mucosa of sheep. 299 48

Amino acid transport was studied in C1 cells which contain amplified levels of sodium- and potassium-activated adenosine triphosphatase (Na,K-ATPase), in C4 cells which are ouabain-sensitive revertants, and in parental HeLa S3. Sodium-dependent uptake of aminoisobutyric acid and alanine was increased 2-fold in the amplified C1 cells. After a 6 h amino acid starvation period, the rate of sodium-dependent uptake of methylaminoisobutyric acid was 70-90% greater for C1 than for C4 and HeLa. This uptake was inhibitable by ouabain and the apparent Km values for high affinity uptake were similar in all three lines. Overall, neutral amino acid uptake through Systems A, ASC, and L was 2-fold higher in the Na,K-ATPase amplified C1 cells relative to C4 or HeLa. The induction of System A uptake of methylaminoisobutyric acid after starvation was more rapid in both the amplified C1 cells and the revertant C4 when compared to HeLa, which suggests that the selection for amplification of the Na,K-ATPase produced membrane alterations affecting the adaptive regulation of System A.
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PMID:Alterations in amino acid transport in Na,K-ATPase amplified HeLa cells. 300 Oct 56

The effect of Ep on different ATPases and acetylcholinesterase of rat RBC membrane was studied. Starvation caused a slight decrease in Mg2+-, Ca2+-, and Na+ + K+-ATPases. However, these enzyme activities were markedly increased on Ep treatment of starved rats. Specific activities of all three ATPases increased linearly with increasing concentration of Ep. Under identical conditions the hormone failed to stimulate the ATPase activity of liver plasma membrane. Desensitization by fluoride of allosteric inhibition of erythrocyte membrane-bound Na+ + K+-ATPase was observed under starvation which showed a return to normal n values on Ep administration. The enzyme from normal animals was inhibited almost completely at 0.1 mM fluoride whereas enzyme from starved and Ep-treated animals showed only about 50% inhibition at that fluoride concentration. Ep increased the acetylcholinesterase activity of normal RBC membrane to a small extent whereas the stimulation was much higher under starvation. The fluoride inhibition curve of this enzyme changed from sigmoidal to hyperbolic under starvation which again changed to allosteric on administration of Ep. These changes were closely correlated to n values. Red blood cells of Ep-treated animals became more susceptible to osmotic shock under the experimental conditions.
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PMID:Effect of erythropoietin on the different ATPases and acetylcholinesterase of rat RBC membrane. 302 76


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