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

Tetrahymena thermophila cells grown in a synthetic nutrient medium for 9 h removed 97% of the free L-arginine but less than 50% of any of the other essential amino acids. The major portion of the arginine was degraded rapidly (76-92%) whereas 5-15% was conserved as intact and only 2.5-10% were incorporated into protein. However, if bovine serum albumin (BSA) was present in the medium as a macromolecular arginine source the incorporation of free arginine into protein was reduced to less than 1% but the degraded fraction was increased. Apparently, the uptake mode of arginine determines its fate: arginine taken up by phagocytosis is bound for protein biosynthesis, arginine taken up by membrane receptors is chanelled to degradation. Media without arginine did not support growth of Tetrahymena. Citrulline and ornithine, the precursors of arginine biosynthesis in yeast and vertebrates, were not able to substitute for arginine. Pronounced morphological changes, e.g. greatly reduced ribosome content, were observed in Tetrahymena cells after 24 h of arginine starvation in otherwise complete medium, but not in cells starved in water, salt solution, or buffer. Thus, arginine is an essential nutrient component for Tetrahymena and the rapid degradation of this compound involving the enzymes arginine deiminase (ADI) and citrulline hydrolase (CH) might be of regulatory importance for the unicellular, as it is the case with acetylcholine and catecholamines in mammalian organisms. Since the product of these enzymes, L-ornithine, is the substrate for the regulatory key enzyme of polyamine biosynthesis, ornithine decarboxylase (ODC), the effects of the presence of absence of arginine on the activities of each particular enzyme of the pathway were studied, including ODC and the enzyme ornithine-oxo-acid aminotransferase (O delta T), which is a competitor of ODC for the common substrate. The arginine-degradative pathway was stimulated by extracellular free but not by peptide-bound arginine and was modulated by extracellular protein which induced phagocytosis; O delta T was stimulated with a time lag. The stimulation of ODC was in a reciprocal relation to the arginine concentration and enhanced by phagocytosis and previous arginine starvation.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Stimulation of growth and polyamine biosynthesis of the ciliated protozoan Tetrahymena thermophila. Regulation by L-arginine. 261 Sep 29

PCM can be usefully considered in terms of edematous (kwashiorkor-like) and nonedematous (marasmic) forms, as long as the limitations of the traditional terms are kept in mind. The body composition of subjects with undernutrition, or total starvation, both appear to maintain an extracellular fluid volume at a normal level, which increases as a percentage of the shrinking body weight. This is in contrast to patients with hospital malnutrition, in whom there is often an absolute increase in the extracellular volume while the body cell mass is shrinking. Data from the starvation literature suggest that the adult subject must gain approximately 10% of his or her body weight as extracellular expansion before edema is clinically evident. Preliminary evidence indicates that the hospitalized patient with the edematous form of malnutrition is at greater risk for complications and death when undergoing an operation, or requiring intensive care. The depleted patient who shows a rise in a depressed serum albumin after 7 to 10 days of TPN will have an improved prognosis when undergoing the stress of an elective operation. This improvement appears to be more the result of decreasing the expanded extracellular fluid volume than achieving a major increase in protein stores. The severely catabolic patient, particularly during episodes of major infection, can be expected to benefit by a nutritional intake that is carefully designed to provide calorie and nitrogen equilibrium. Nutritional intake high enough to guarantee positive balances of calories and nitrogen should be delayed until the acute catabolic stimulus has subsided, at which time the nutritional objective is to rebuild lost tissue.
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PMID:Forms of malnutrition in stressed and unstressed patients. 308 75

The influence of nutritional status on the resumption of adequate food intake in 101 patients recovering from colorectal cancer operation was examined. Two thirds of these patients were well-nourished; the others were malnourished. Malnutrition criteria were serum albumin of less than 3.5 gm per dl plus any two of the following four factors: recent weight loss greater than 10 per cent or weight for height, mid-arm circumference, and triceps skinfold thickness lower than the tenth percentile. Over half of the well-nourished patients were eating 60 per cent or greater of their caloric requirements by the tenth postoperative day, whereas only one quarter of the malnourished patients had attained this intake. the morbidity and mortality in 33 malnourished patients was 52 and 12 per cent, respectively, compared with 31 and 6 per cent (p less than 0.01) in 68 nourished patients. The duration of postoperative functional starvation in malnourished patients without complications increased to an average of 22 days following a complication and was further prolonged after a complication. Age or operative procedure (curative or palliative) did not influence complication rate. Our data suggest that postoperative nutritional support as either TPN or enteral feeding using an elemental diet is indicated in malnourished patients and in well-nourished patients immediately following a complication requiring therapeutic intervention.
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PMID:Influence of nutritional status on the resumption of adequate food intake in patients recovering from colorectal cancer operations. 309 45

The extracellular acidic proteinase (EC 3.4.23.6) produced by Candida albicans has been reported to be a virulence factor. In studying the role of this proteinase in human disease, we determined the optimum conditions for stimulating proteinase production in order to isolate proteinase-negative (Prt-) mutants. We found that in liquid medium containing bovine serum albumin (BSA) as the sole nitrogen source, at pH 4 and 27 degrees C, the sensitivity of proteinase detection was considerably greater than when assayed on BSA agar at 37 degrees C. This observation is due, in part, to temperature sensitivity of proteinase induction. Nitrogen starvation did not induce proteinase. Proteinase production on agar was increased by adding 0.01% yeast extract (YE) to BSA medium. Using BSA + YE agar to isolate mutants, it was discovered that C. albicans ATCC 28366 was heterozygous for a Prt- mutation. Spontaneous Prt- mutants occurred at a frequency of 2 x 10(-3). Ultraviolet light increased the mitotic segregation of Prt- cells to a frequency of 1 x 10(-2). The Prt- phenotype showed a large inoculum effect, Prt- segregants reverted with a high frequency, and the revertants were unstable.
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PMID:Segregation of proteinase-negative mutants from heterozygous Candida albicans. 332 78

Among the elderly, those at highest risk are the chronically ill, inactive patients. Assessing macronutrient requirements and outcome depends on longitudinal studies. Seven chronically ill, elderly female patients suffering from persistent infections, were studied monthly, over a 6-month period to determine their protein and energy requirements. Calorie and protein requirements were based on clinical status. The results of the nutrition support program were monitored using: weight change, nitrogen balance, serum albumin levels, alterations in anthropometric measurements (triceps skinfold thickness and arm muscle circumference), and immune function tests. Based on the 6-month study period data, the calculated mean energy requirement for weight maintenance was 98% of calculated basal energy expenditure (BEE) and the mean protein required for nitrogen balance, 0.8 g/kg desired body weight (DBW). Excess caloric administration resulted in weight gain, determined to be fat (and/or fluid) but not lean body mass. When surgery is contemplated, there should be a 30% (factorial) increase over these base-line values. It is inadvisable to allow elderly patients to sustain any starvation, period given their inability to produce increases in body cell mass even in this 6-month period.
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PMID:Nutritional support of the chronically ill elderly female at risk for elective or urgent surgery. 334 73

1. Plasma fibronectin, a glycoprotein, is an opsonin of the reticuloendothelial system. 2. In ten healthy volunteers starved for 4.5 d, daily measurements showed a rapid reduction in plasma fibronectin, no alteration in either C3 or plasma transferrin and, at the end of the starvation period, an elevated serum albumin. 3. On refeeding, plasma fibronectin rapidly returned to its prestarvation level but plasma transferrin was significantly reduced and did not recover by the end of the study. 4. Changes in plasma fibronectin may be a sensitive index of nutritional status. The reduction of plasma fibronectin in short-term starvation may compromise host defence tolerance of injury and sepsis.
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PMID:Changes in plasma fibronectin during acute nutritional deprivation in healthy human subjects. 366 79

Seventy-two hour starvation in neonatal rabbits was studied. Fasted animals received no feeds, only water every 8 h for 72 h. Fed animals were suckled by the dam. There was no difference in birth weight, serum albumin, blood urea nitrogen, electrolytes, or urine specific gravity between fed and fasted animals. Weight at 72 hr was less in fasted (p less than 0.01) than fed rabbits. Serum cortisol (p less than 0.05) and corticosterone (p less than 0.01) levels were higher in the fasted group. Proximal and distal small bowel homogenates had less DNA and protein (p less than 0.01) in the fasted group, but the protein/DNA ratio was the same in the proximal and distal small bowel homogenates from both groups. Sucrase (E.C.3.2.1.26) specific activity was significantly increased in proximal small bowel homogenates from the fasted group (p less than 0.01) but was the same in distal small bowel homogenates from both groups. Sucrase total activity per proximal segment was the same in fed and fasted animals but was significantly less per segment in distal small bowel homogenates from fasted animals. Alkaline phosphatase (E.C.3.1.3) total and specific activity was decreased in proximal (p less than 0.01) and distal (p less than 0.05) small bowel homogenates from the fasted group. Lactase (E.C.3.2.1.23) total activity was decreased in proximal and distal (p less than 0.01) small bowel homogenates from the fasted group but lactase specific activity was unchanged. Thus, a brief period of malnutrition in neonatal animals can result in a variety of regional functional changes in the gastrointestinal mucosa.
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PMID:Short-term malnutrition in neonatal rabbits. I. Brush border enzymes. 368 82

The value of crystalline amino acids compared with glucose in maintaining functional muscle mass (maximum exercise capacity) in the perioperative period was studied. Twelve surgical patients received 100 g of glucose (Group 1) for 7 to 10 days perioperatively, and 12 (Group 2) received 90 g of crystalline amino acids for a similar period. Maximum exercise capacity, nitrogen balance, and serum albumin were studied. The use of amino acids instead of glucose spared nitrogen. Net nitrogen loss was 64.7 +/- 6.7 g in Group 1 compared with 34.7 +/- 4 g in Group 2 (p less than or equal to 0.001). Exercise capacity decreased 13.8 +/- 4.5 percent in Group 1 and 13.3 +/- 2.9 percent in group 2. The serum albumin level decreased by 0.30 +/- 0.2 g/100 ml in Group 1 compared with 0.34 +/- 0.15 g/100 ml in Group 2. These differences were not significant. Changes in serum albumin were correlated with changes in exercise capacity (r = 0.7, p less than or equal to 0.002), but neither was significantly correlated with nitrogen loss. We concluded that the use of amino acids instead of glucose during moderate periods of semi-starvation associated with moderate trauma will not influence loss of exercise capacity significantly, although some nitrogen will be spared; patients undergoing moderately severe surgical procedures accompanied by moderate periods of semistarvation will lose approximately 14 percent of their exercise capacity; and loss of exercise capacity is not correlated with loss of nitrogen under these conditions but is loosely correlated with changes in serum albumin levels.
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PMID:Relative value of glucose and amino acids in preserving exercise capacity in the postoperative period. 397 97

The compromised human newborn frequently presents with overwhelming feeding problems which lead to inadequate intake. These problems may affect the development of the small intestine, especially mucosal barrier function, leading to increased infections and susceptibility to allergens. To study this, an animal model was established using neonatal rabbits deprived of nutrients from birth until 72 h. Mucosal barrier function was compared in deprived and control (naturally fed 72-h-old animals) rabbits by measuring immunoreactive bovine serum albumin in serum 4 h after intragastric infusion of crystalline bovine serum albumin (200 mg/100 g body weight). Trypsin activity was measured in rinse fluid obtained from the small intestine. Representative sections of jejunum from control and experimental animals were formalin fixed and stained with hematoxylin and eosin for morphologic comparison. Following the bovine serum albumin feeding, a significantly increased serum immunoreactive bovine serum albumin and significantly decreased trypsin-like activity of the small intestinal rinse fluid was noted in starved animals compared to controls. In addition, the enterocytes of malnourished animals were more cuboidal and contained fewer and smaller supranuclear granules on microscopic examination than the enterocytes of controls. This study suggests that short-term starvation in newborns affects mucosal barrier function. Acute starvation may place newborns at increased risk for infections and allergic disease.
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PMID:The effect of short-term starvation on mucosal barrier function in the newborn rabbit. 402 79

We previously described an arginase-deficient, polyamine-dependent Chinese hamster ovary cell line which grows in serum-free medium. From this strain we isolated a new mutant strain that has no detectable catalytic ornithine decarboxylase activity. The mutant cells contain, however, immunoreactive ornithine decarboxylase-like protein roughly in the same quantity as the parent strain. The mutant and the parent cell line strains also contain similar amounts of ornithine decarboxylase-mRNA hybridizable to a specific cDNA. If polyamines are omitted from the medium, proliferation of the mutant cells is considerably retarded and ceases in 6 to 10 days. Addition of ornithine or alpha-difluoromethylornithine, a specific inhibitor of ornithine decarboxylase, has no effect on these cells. Putrescine and spermidine decreased in the mutant cells to undetectable levels during polyamine starvation, whereas spermine was reduced to 1/5th of that found in the control cultures. Polyamines appear to be indispensable for the mutant strain, but this was obvious only after the amount of polyamines, found as impurities in bovine serum albumin used in the medium, was reduced by dialysis to 10(-12) M. Because sera contain polyamines, the ability of the mutant strain to grow in serum-free medium is a great advantage in elucidation of the mechanisms of polyamine function.
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PMID:Mutant strain of Chinese hamster ovary cells with no detectable ornithine decarboxylase activity. 403 57


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