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

Starvation induced changes in the intralysosomal proteolysis in rat liver were assessed in terms of the degradation of intravenously administered [131I]-human serum albumin 30 min after injection. Fasting for five days resulted in nearly 11% increase in the endocytic uptake of the labeled protein in lysosome rich fraction. However, the rate of degradation of internalized protein measured in terms of TCA soluble products showed a distinct decline in starved animals as compared to fed controls. The observed decrease in proteolysis was reversed completely by refeeding the starved rats for 10 days. The restoration of the degradation profiles in fasted animals was also accomplished by isolating lysosomes at a post injection period of 90 min. The results indicated that the starvation induced decrease in proteolysis was a consequence of delayed fusion of lysosomes and the phagosome containing the labeled protein.
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PMID:Influence of starvation on the intra-lysosomal proteolysis in rat liver. 406 50

Fixation of (131)I-serum albumin by Ehrlich ascites tumor cells in suspensions and sarcoma S-180 monolayers was measured under experimental conditions. Anaerobic incubation and inhibitors of the oxidative metabolism critically restricted the range of glucose concentrations capable of supporting cell life; in glucose concentrations higher than 10(-2)M, Ehrlich cells suffered from their own acid production; in concentrations 10(-2)M, lower than they underwent damage by starvation. Both types of damage were accompanied by increased albumin fixation unrelated to pinocytosis. Different procedures recommended to enhance the uptake of infectious viral RNA by animal cells in culture were tested for their ability to increase albumin uptake. They enhanced the penetration of both albumin and vital dyes and decreased the viability of cell populations. Their effect, therefore, is related to cell damage. It was postulated that reversible damage to cells favors RNA infection by leading to abnormal uptake processes and by decreasing intracellular digestion. This abnormal uptake is different from pinocytosis and also from the massive fixation of albumin to dead cells. The latter phenomenon is due to adsorption by intracellular sites exposed by disruption of the cell membrane. Polycations are able to induce all three forms of fixation depending on the experimental conditions.
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PMID:Studies on protein uptake by isolated tumor cells. 3. Apparent stimulations due to pH, hypertonicity, polycations, or dehydration and their relation to the enhanced penetration of infectious nucleic acids. 603 87

This study evaluated the effect of 5 days of starvation followed by 5 days of refeeding on immunoreactive plasma and serum fibronectin and associated opsonic activity as studied by peritoneal macrophage monolayer bioassay in 12 healthy women volunteers. The temporal alteration of fibronectin was compared with the serum albumin, total iron-binding capacity, and retinol-binding protein levels. Fibronectin concentration and opsonic activity were also determined in two cachectic patients who were 61 and 78% of their ideal body weight. Prior to starvation, plasma fibronectin was 292 +/- 20 micrograms/ml and serum fibronectin was 182 +/- 16 in all subjects. After 5 days of starvation, immunoreactive fibronectin decreased (p less than 0.05) by 20-25%. This decrease was not great enough to impair opsonic activity as tested by the in vitro macrophage assay. Starvation caused no decrease in serum albumin or total iron-binding capacity, although retinol-binding protein decreased by 35%. During refeeding, subjects were randomized to a diet with (n = 6) and without (n = 6) carbohydrate. After 5 days of refeeding, fibronectin levels were normalized on the carbohydrate-containing diet, but were still low (82% of normal) on the carbohydrate-free diet. Retinol-binding protein did not fully normalize after 5 days of refeeding. In the two cachectic patients, fibronectin levels prior to total parenteral nutrition were 25 and 75% of normal. Thus, starvation can lower fibronectin levels and this protein is rapidly restored with adequate nutrition.
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PMID:Decreased plasma fibronectin during starvation in man. 642 59

This study was undertaken to determine the changes in basic nutritional indices associated with major colonic surgery accompanied by periods of semi-starvation. Changes in weight, serum albumin, nitrogen balance, and maximum exercise capacity were studied. Weight loss was 5.5 +/- 1 per cent, serum albumin decreased 0.20 +/- 0.15 gm per cent. Nitrogen loss was 5.9 +/- 0.9 gm per day and maximum exercise capacity decreased by 13.5 +/- 1.8 per cent. Nitrogen balance improved when amino acids were substituted for glucose as the maintenance regimen, but no corresponding improvement in exercise performance could be demonstrated. It is concluded that major colonic surgery associated with moderate periods of semi-starvation is associated with an average nitrogen loss of 5.9 +/- 0.9 gm per day and a 13.5 +/- 1.8 per cent loss in maximum exercise capacity or effective muscle mass.
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PMID:An assessment of nutritional depletion following major colonic surgery. 648 74

Patients requiring long term intensive care and/or prolonged ventilatory support, are frequently undergoing progressive malnutrition, occasionally complicated by a hypercatabolic state. Sepsis, fever and the requirements for postoperative healing will add further nutritional demands on such patients. In contrast to starvation, critically ill patients maintained on protein-free energy-deficient diet do not adapt to utilization of their lipid to provide energy needs. Mobilization of endogenous fat stores is reduced, and this reduction leads to increased gluconeogenesis from amino acids derived from muscle protein to meet the increased energy needs. Low serum albumin, possible low surfactant production, devitalization of the alveolo-capillary membrane and impaired immunocompetence could contribute to the development of pulmonary transudation, alveolar collapse, low compliance and pulmonary infection. Such sequelae of a protein-free energy-deficient diet would delay weaning patients off prolonged mechanical ventilation. Nutritional assessment, which may be determined serially, and means of nutritional support are outlined.
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PMID:Nutritional support in long term intensive care with special reference to ventilator patients: a review. 678 7

We had noted that a number of hospitalized patients showed abnormally low serum albumin levels within a few days of admission, although the albumin had been normal at admission. Since this rapid decline in albumin could not be accounted for on the basis of starvation, we hypothesized that the changes were due to the increase in intravascular fluid volume which normally occurs with assumption of the recumbent position. Since albumin is often a nutritional screening parameter in hospitalized patients, it is important to ascertain the incidence of such profound changes in albumin as well as to identify possible causes for this change. A survey of 34 concurrent hospital admissions showed that 28 out of 34 (82%) patients had a decline in serum albumin within 5 days of hospitalization. These 28 patients had a decrease of 0.5 +/- 0.09 g/dl. Twenty-five additional patients were studied in order to elucidate causative factors. Twenty out of the 25 showed a decrease in serum albumin within 5 days of admission (mean decrease 0.5 +/- 0.05 g/dl). Hemoglobins in these patients decreased by a mean of 1.1 +/- 0.34 g/dl (p less than 0.01), but BUN and uric acid levels did not change significantly. The one factor common to all patients with declining albumin values was change in posture. All patients were ambulatory at the time of the initial albumin determination but were on bedrest for at least 6 1/2 hours before the second determination. The findings indicate that most hospitalized patients have significant changes in serum albumin levels which occur with change in posture. If the albumin level is to be used as a nutritional indicator, the patient's position at the time of phlebotomy is essential for accurate interpretation of results.
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PMID:Rapidly declining serum albumin values in newly hospitalized patients: prevalence, severity, and contributory factors. 680 74

We report that Chinese hamster ovary cells assemble membrane phospholipids from choline-linked lipid present in fetal calf serum. This was examined by testing the ability of various serum preparations to satisfy the choline requirement of the cells. Chinese hamster ovary cells divided in growth medium containing lipoprotein-deficient serum and approximately 8 microM lysolecithin. Identical results were obtained in growth medium supplemented with solvent-extracted (delipidated) serum reconstituted with purified egg lysolecithin and the uptake of lipid was inhibited by the addition of bovine serum albumin. Analysis of the phospholipid composition of cells incubated with 32Pi and egg lysolecithin in place of choline revealed that approximately 30% of the phosphorus moieties of the cellular phospholipids were derived from the added lipid, while in the presence of choline less than 10% arose in this fashion. Choline starvation enhanced the formation of lecithin from [32P]lysolecithin without affecting phospholipid turnover and labeled lecithin was converted to other phospholipids, especially sphingomyelin and phosphatidylserine. Unlike endogenous serum lysolecithin, lipoproteins obtained from human and fetal calf sera failed to satisfy the choline requirement of Chinese hamster ovary cells, even though 95% of the lipoprotein phospholipid was phosphatidylcholine and sphingomyelin. Together, these results demonstrate that animal cells can derive all of the choline required for membrane phospholipid synthesis from serum lysolecithin and that its conversion to lecithin within the cell is regulated by the availability of choline. In contrast, serum lipoproteins do not normally serve as a major source of choline moieties.
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PMID:Biosynthesis of phosphatidylcholine from serum phospholipids in Chinese hamster ovary cells deprived of choline. 682 51

To investigate the effect of stress on the dynamics of serum protein response during starvation, serum albumin, prealbumin, and transferrin changes were studied in six chair-adapted macaques during two separate 7-day test periods: (1) Starvation--NPO + IV D5/W (100 cc/kg/day), and (2) Surgery/starvation--laparotomy and gastrostomy + NPO + IV D5/W (100 cc/kg/day). During the starvation period, transferrin was the only protein that decreased from baseline values and did so at day 7 of the study period. In contrast, during the period of starvation following surgery, both prealbumin and transferrin were significantly decreased at both day 4 and day 7 of the study period, whereas albumin was only decreased at day 7 of this period. These findings indicate that the addition of a surgical stress to starvation results in a depression of serum protein levels that is not only of greater magnitude, but also more rapid in onset than observed with starvation alone. In addition, the differential response of prealbumin and transferrin to starvation and stress may provide a useful indicator of the presence and/or degree of stress in certain situations. The clinical utility of this finding remains to be ascertained.
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PMID:Serum protein response to surgery and starvation. 689 11

The resting metabolic expenditure of 65 patients with advanced cancer was measured by indirect calorimetry. Resting metabolic expenditure was found to be abnormally high in about 60 per cent of the patients, and there was a strong correlation between resting metabolic expenditure and weight loss and between resting metabolic expenditure and variation in serum transferrin. No relation was observed between resting metabolic expenditure and serum albumin or between resting metabolic expenditure and creatinine-height index. We suggest that these high values of resting metabolic rate, despite the weight loss and starvation, could play a role in the genesis of malnutrition in patients with cancer. The importance of these findings for an adequate planning of nutritional rehabilitation of patients with cancer is emphasized.
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PMID:Excessive caloric expenditure as a cause of malnutrition in patients with cancer. 735 15

An important goal for the investigation of the proliferation of mammalian cells is to establish a fully defined condition for culturing them in vitro. Here, we report establishment of a fully defined culture condition that supports the primary culture of normal c-kit+IL-7 receptor (IL-7R)+ B precursor cells without the aid of stromal cell lines. This defined culture condition contains IL-7, the ligand for c-kit, transferrin, insulin, and bovine serum albumin as protein components. By using the cell lines derived from RAG2(-/-) mice, which do not differentiate into c-kit- stage, we have evaluated the role of each protein in the cell cycle progression of c-kit+IL-7R+ B precursor cells. Since B precursor cells can grow without insulin, c-kit remains a sole functional receptor tyrosine kinase for their growth. While both c-kit ligand (KL) and IL-7 are the requisite molecules for sustained proliferation of B precursor cells, each molecule plays distinct roles. IL-7 starvation results in prompt arrest of the cells at G1. An accumulation of the cells in the mitotic phase was also detected. Thus, the major role of IL-7 is to regulate the G1/S transition and the process of cytokinesis of B precursor cells. Although prolonged KL starvation over 48 h resulted in accumulation of G1 cells, its effect could not be detected within 24 h, which is long enough for all the cells to complete one cell cycle. This suggests that KL might be involved in the cell cycle progression of B precursor cells in a manner that its signal could still be effective in the one or two cell cycles that follow. Although molecular nature of the signals underlying the present observation awaits future investigation, the method described in this report would provide a useful model system for investigating the signaling pathways that are involved in the cell cycle progression of B precursor cells.
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PMID:Cell cycle control of c-kit+IL-7R+ B precursor cells by two distinct signals derived from IL-7 receptor and c-kit in a fully defined medium. 754 34


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