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

Total starvation in the rat for 2 days did not alter the hypothalamic content of thyrotropin-releasing hormone (TRH), but did decrease both pituitary TSH content and serum TSH concentration. Five days starvation resulted in a significant decrease in serum TSH and a slightly enhanced serum TSH response to exogenous TRH, suggesting that the pituitary retains its sensitivity to TRH. Fasting for 5 days resulted in a decreased 1 and 4th, but an increased 24th thyroid 131I uptake. Other starvation-induced abnormalities of intrathyroid 131I metabolism were a consistent increase in the percent of organified 131I present as MIT and DIT and a decreased percent 131I labeled T4 AND T3. These alterations in the intrathyroid metabolism of 131I in the starved rat probably reflect both a decrease in serum TSH concentration and a decrease in urinary and fecal loss of administered 131I. The serum total and free T4 and total and free T3 concentrations were decreased following 2 and 5 days of starvation.
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PMID:Effect of starvation on hypothalamic-pituitary-thyroid function in the rat. 9 84

Kidney and liver mitochondria of rat, rabbit and guinea pig are able to transform 3-hydroxy-3-methylglutarate into acetoacetate, whereas ox liver mitochondria and rat mitochondria of heart, diaphragm and brain do not exhibit such an activity. Starvation and streptozotocin treatment decreases the formation of acetoacetate from 3-hydroxy-3-methylglutarate. Addition of acetoacetate and succinate to the incubation media of mitochondria results in a decrease in the transformation of 3-hydroxy-3-methylglutarate into acetoacetate. A 3-hydroxy-3-methylglutaryl-CoA hydrolase is present in rat liver mitochondria; the activity does not show appreciable changes after starvation or streptozotocin treatment.
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PMID:Formation and utilization of 3-hydroxy-3-methylglutarate in liver mitochondria of starved and streptozotocin-diabetic rats. 9 38

Aspartate transcarbamylase is synthesized during exponential growth of Bacillus subtilis and is inactivated when the cells enter the stationary phase. This work is a study of the regulation of aspartate transcarbamylase synthesis during growth and the stationary phase. Using specific immunoprecipitation of aspartate transcarbamylase from extracts of cells pulse-labeled with tritiated leucine, we showed that the synthesis of the enzyme decreased very rapidly at the end of exponential growth and was barely detectable during inactivation of the enzyme. Synthesis of most cell proteins continued during this time. When the cells ceased growing because of pyrimidine starvation of a uracil auxotroph, however, synthesis and inactivation occurred simultaneously. Measurement of pools of pyrimidine nucleotides and guanosine tetra- and pentaphosphate demonstrated that failure to synthesize aspartate transcarbamylase in the stationary phase was not explained by simple repression by these compounds. The cessation of aspartate transcarbamylase synthesis may reflect the shutting off of a "vegetative gene" as part of the program of differential gene expression during sporulation. However, aspartate transcarbamylase synthesis decreased normally at the end of exponential growth at the nonpermissive temperature in a mutant strain that is temperature-sensitive in sporulation and RNA polymerase function. Cessation of aspartate transcarbamylase synthesis appeared to be normal in three other temperature-sensitive RNA polymerase mutants and in several classes of spo0 mutants.
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PMID:Aspartate transcarbamylase synthesis ceases prior to inactivation of the enzyme in Bacillus subtilis. 9 40

A simple defined medium (neisseria defined medium) was devised that does not require iron extraction to produce iron-limited growth of Neisseria meningitidis (SDIC). Comparison of this medium to Mueller-Hinton broth and agar showed nearly identical growth rates and yields. The defined medium was used in batch cultures to determine the disappearance of iron from the medium and its uptake by cells. To avoid a number of problems inherent in batch culture, continuous culture, in which iron and dissolved oxygen were varied independently, was used. Most of the cellular iron was found to be nonheme and associated with the particulate fraction in sonically disrupted cells. Nonheme and catalase-heme iron were reduced by iron starvation far more than cytochromes b and c and N,N,N',N'-tetramethylphenylenediamine-oxidase. The respiration rate and efficiency also decreased under iron limitation, whereas generation times increased. The iron-starved meningococcus took up iron by an energy-independent system operating in the first minute after an iron pulse and a slower energy-dependent system inhibited by respiratory poisons and an uncoupler. The energy-dependent system showed saturation kinetics and was stimulated nearly fourfold by iron privation. In addition, to determine the availability to the meningococcus of the iron in selected compounds, a sensitive assay was devised in which an iron-limited continuous culture was pulsed with the iron-containing compound.
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PMID:Iron in Neisseria meningitidis: minimum requirements, effects of limitation, and characteristics of uptake. 10 16

Two novel procedures have been used to regulate, in vivo, the formation of phosphoenolpyruvate (PEP) from glycolysis in Streptococcus lactis ML3. In the first procedure, glucose metabolism was specifically inhibited by p-chloromercuribenzoate. Autoradiographic and enzymatic analyses showed that the cells contained glucose 6-phosphate, fructose 6-phosphate, fructose-1,6-diphosphate, and triose phosphates. Dithiothreitol reversed the p-chloromercuribenzoate inhibition, and these intermediates were rapidly and quantitatively transformed into 3- and 2-phosphoglycerates plus PEP. The three intermediates were not further metabolized and constituted the intracellular PEP potential. The second procedure simply involved starvation of the organisms. The starved cells were devoid of glucose 6-phosphate, fructose 6-phosphate, fructose- 1,6-diphosphate, and triose phosphates but contained high levels of 3- and 2-phosphoglycerates and PEP (ca. 40 mM in total). The capacity to regulate PEP formation in vivo permitted the characterization of glucose and lactose phosphotransferase systems in physiologically intact cells. Evidence has been obtained for "feed forward" activation of pyruvate kinase in vivo by phosphorylated intermediates formed before the glyceraldehyde-3-phosphate dehydrogenase reaction in the glycolytic sequence. The data suggest that pyruvate kinase (an allosteric enzyme) plays a key role in the regulation of glycolysis and phosphotransferase system functions in S. lactis ML3.
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PMID:In vivo regulation of glycolysis and characterization of sugar: phosphotransferase systems in Streptococcus lactis. 10 23

In order to obtain or maintain a good nutritional status in cancer patients, it is often necessary to perform intravenous nutrition. In summary, several studies have indicated that intravenous nutrition may be beneficial in association with surgery, radiation, or chemotherapy in patients with cancer. More controlled studies, however, are required. There is no indication at the present time of any adverse effects of this method of treatment in relation to tumor growth. The general nutritional improvement in patients on intravenous nutrition increases the immunocompetence, resistance to radiation and cytostatics as well as the mood and quality of life of the cancer patients. In very broad terms this new intravenous nutrition therapy means that a cancer patient should not be left without specific cancer therapy because of starvation and its serious or even fatal complications.
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PMID:[General aspects of intravenous feeding of cancer patients]. 10 21

Regeneration of the pigment system of Anacystis nidulans was studied following nitrate starvation. Three new, distinct fluorescence bands, at 596, 615 and 636 nm attributed to sensitizing phycobilin chromophores were detected. They each possess a separate excitation band at 425, 395 and 410 nm, respectively.
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PMID:Fluorescence from sensitizing phycobilin chromophores in the blue-green alga Anacystis nidulans. 10 40

Plasma thyroxine concentration was measured in ducks by the thyroxine-binding globulin technique. The assay allowed us to detect annual variations in thyroid activity as well as significant changes after starvation or cold exposure. No detectable thyroxine was formed in surgically thyroidectomized ducks.
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PMID:Estimation of plasma thyroxine concentration in ducks in relation to different environmental and experimental conditions. 10 25

Parenteral nutrition therapy was born 35 to 40 years ago when the first steps were taken to perform a protein nutrition by the intravenous supply of amino acids in man. Since that time, many efforts have been made to supply adequate amounts of energy intravenously. These efforts have resulted in the two available systems for parenteral nutrition: the lipid-carbohydrate system and the glucose system. The lipid-carbohydrate system, which corresponds to the nutrient content of normal food, may be given either in a peripheral vein or through a central vein catheter. The glucose system is administered through a central venous catheter. Many problems concerning the parenteral nutrition need to be solved and further elucidated. However, our present knowledge and technique in this field are far advanced over earlier methods. Now all patients who cannot take food in adequate amounts orally or enterally may be kept in good nutritional status by parenteral nutrition. In this way it is possible to prevent starvation and its complications in these patients.
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PMID:Parenteral nutrition. 10 10

The current rapid expansion of the human population on earth, particularly in the less developed countries, raises the possibility of widespread, serious malnutrition and starvation for many unless agricultural technology can intervene with appropriate answers to these problems. Plant breeders have been charged with developing varieties that will yield larger quantities of improved quality protein. Since the realization that maize having the opaque-2 gene has markedly improved protein quality, much work has been done in many areas of research to apply this discovery as well as to learn more about alternative methods to attain the same goals. This discussion will be a review of the advances so far attained by plant breeders in their efforts to develop maize with improved protein quantity and quality. Work concerning the utilization of mutant genes that improve protein quality and efforts at exploiting the naturally occurring variation for protein quality and quantity will be examined. Work that has been done in other related fields that has relevance to the protein improvement problem will also be examined. Screening and subsequent regeneration of tissue cultures as well as work concerning the biochemical energetics of yield and protein improvement will be examined in order to bring the problem of breeding for protein improvement into perspective. Finally, the corn industry's experience with improving protein quality and quantity will provide a basis for discussing the economic considerations of such improvement.
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PMID:The current status of breeding for protein quality in corn. 10 73


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