Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The objective of this investigation was to throw light on the biological behavior and metabolic regulation of hepatic enzymes of the nonoxidative branch of the pentose phosphate pathway. The activities of transaldolase (EC 2.2.1.2) and trasketolase (EC 2.2.1.1) Were compared in biological conditions that involve modulation of gene expression such as in starvation, in differentiation, after partial hepatectomy, and in a spectrum of hepatomas of different growth rates. The enzyme activities were determined under optimal kinetic conditions by spectrophotometric methods in the 100,000 X g supernatant fluids prepared from tissue homogenates. The kinetic properties of transaldolase and transketolase were similar in normal liver and in rapidly growing hepatoma 3924A. For transaldolase, apparent Km values of 0.13 mM (normal liver) and 0.17 mM (hepatoma) were observed for erythrose 4-phosphate and of 0.30 to 0.35 mM for fructose 6-phosphate. The pH optima in liver and hepatoma were at approximately 6.9 to 7.2. For the transketolase substrates, ribose 5-phosphate and xylulose 5-phosphate, the apparent Km values were 0.3 and 0.5 mM, respectively, in both liver and hepatoma. A broad pH optimum around 7.6 was observed in both tissues. In organ distribution studies, enzyme activities were measured in liver, intestinal mucosa, thymus, kidney, spleen, brain, adipose tissue, lung, heart, and skeletal muscle. Taking the specific activity of liver as 100%, transaldolase activity was the highest in intestinal mucosa (316%) and in thymus (219%); it was the lowest in heart (53%) and in skeletal muscle (21%). Transketolase activity was highest in kidney (155%) and lowest in heart (26%) and skeletal muscle (23%). Starvation decreased transaldolase and transketolase activities in 6 days to 69 and 74%, respectively, of those of the liver of the normal, fed rat. This was in the same range as the decrease in the protein concentration (66%y. In the liver tumors, transaldolase activity was increased 1.5- to 3.4-fold over the activities observed in normal control rat liver. Transketolase activity showed no relationship to tumor proliferation rate. In the regenerating liver at 24 hr after partial hepatectomy, the activity of both pentose phosphate pathway enzymes was in the same range as that of the sham-operated controls. In differentiation at the postnatal age of 5, 12, 23, and 32 days, hepatic transaldolase activities were 33, 44, 55, and 72%, respectively, of the activities observed in the 60-day-old, adult male rat. During the same period, transketolase activ-ties were 18, 21, 26, and 55% of the activities observed in liver of adult rat. The demonstration of increased transaldolase activity in hepatomas, irrespective of the degree of tumor malignancy, differentiation, or growth rate, suggests that the reprogramming of gene expression in malignant transformation is linked with an increase in the expression of this pentose phosphate pathway enzyme...
Cancer Res 1976 Sep
PMID:Behavior of transaldolase (EC 2.2.1.2) and transketolase (EC 2.2.1.1) Activities in normal, neoplastic, differentiating, and regenerating liver. 1 80

The effects of dietary-induced acidosis on the growth and rates of complete regression of Sarcoma 180 in mice have been studied. The experiments here reported have demonstrated that mineral acidification of laboratory food produces a late decrease in tumor growth and significantly increases the rates of complete tumor regression. Blood acid-base studies also demonstrate the effects of these diets in altering the acid-base balance, and seemingly, this is independent of starvation and/or ketosis. The relationships of such in vivo acid-base metabolic changes to the control of tumor metabolism are briefly discussed. A therapeutic potential for this preliminary approach is considered.
Cancer Res 1979 Nov
PMID:Effects of systemic acidification of mice with Sarcoma 180. 4 Jun 91

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.
Cancer Res 1976 Aug
PMID:Synthesis and the lethality of bleomycin in bacteria. 5 23

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.
Cancer Res 1977 Mar
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

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 cytostatic 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 concerning the intravenous feeding of cancer patients]. 9 20

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

In carcinoma of the esophagus, two major factors are operative, both of which are capable of suppressing the immune response, namely starvation and the presence of a malignant tumor. Twenty patients who were treated by palliative intubation for unresectable carcinoma of the esophagus were investigated. All patients were suffering from protein-calorie malnutrition and were shown to be in negative nitrogen balance. Lymphocyte counts and the nonspecific cellular and humoral immune response were evaluated before and after correction of the nutritional deficit. No attempt was made to reduce tumor bulk. The cellular immune response was compromised in all patients. The DNCB skin test was negative, absolute lymphocyte counts and T-lymphocyte numbers were significantly depressed, and the mitogenic response to phytohaemagglutinin (PHA) stimulation also significantly depressed. Immunoglobulin A levels were significantly elevated but serum complement concentrations were normal. Reversal of the negative nitrogen balance resulted in a significant increase in absolute and T-lymphocyte numbers, and a significant increase in the mitogenic response to PHA. The DNCB skin test, however, remained nonreactive. Nutritional repletion also significantly increased serum C(3), C(4) and C(3)PA concentrations. Reversal of negative nitrogen balance may reverse in vitro evidence of immunoparesis and produce an increase in complement concentrations, without therapeutic reduction in the tumor load.
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PMID:Nutritional status and the nonspecific cellular and humoral immune response in esophageal carcinoma. 10 56

Changes in the levels of serine dehydratase and glucose-6-phosphatase induced by dietary stimuli or starvation in hyperplastic nodules of rat liver during diethylnitrosamine or N-2-fluorenylacetamide feeding were studied by immuno- and enzyme histochemical methods. The study was performed during carcinogenesis through a combined method of enzyme histochemistry and radioautography. Serine dehydratase was observed diffusely in the cytoplasm of the original hepatocytes in the periportal zone and was induced markedly during diethynitrosamine feeding but only slightly during N-2-fluorenylacetamide feeding. The enzyme was deficient and not inducible in hyperplastic nodules during their developing phase. Later during the feeding period, however, there was an elevation of the level of serine dehydratase and its inducibility with time in the majority of the nodules. A good correlation was observed between serine dehydratase and glucose-6-phosphatase in their elevated levels and response to enviornmental stimuli. There was a minor group of hyperplastic nodules in which the deficiencies of these enzymes persisted and enzyme induction was not observed. A greater number of hyperplastic nodules with persistent enzyme deficiency was seen during diethylnitrosamine carcinogenesis. These results provide further information about the changing biological nature of hyperplastic nodules with respect to their metabolic adaptability and enzyme levels during hepatocarcinogenesis.
Cancer Res 1975 Apr
PMID:The regulation of serine dehydratase and glucose-6-phosphatase in hyperplastic nodules of rat liver during diethylnitrosamine and N-2-fluorenylacetamide feeding. 16 97

We studied the effect of glucose starvation on glucose uptake and thymidine uptake and incorporation in cultures of normal chicken embryo cells and those transformed by Rous sarcoma virus. Resting normal fibroblasts increased the rate of glucose transport up to tenfold when they were starved for glucose, whereas fast-growing normal cells doubled the rate of uptake after starvation. Transformed cells did not show any change in the rate of glucose uptake during starvation. Thymidine uptake and incorporation by normal and transformed cells were not affected by glucose starvation. These results showed that a decrease in the glucose concentration of the medium induced a specific increase in the rate of glucose transport by normal chick fibroblasts, but did not change the transport of glucose by transformed cells. Therefore, it is suggested that glucose or one of its metabolic products regulated the hexose uptake of normal chick fibroblasts. Virus-transformed cells were insensitive to this regulation.
J Natl Cancer Inst 1975 Feb
PMID:Effects of glucose starvation on normal and rous sarcoma virus-transformed chick cells. 16 6

The behavior of the rate-limiting enzyme of purine catabolism, xanthine oxidase (EC 1.2.3.2); was examined in normal liver, in 17 hepatomas of different growth rates, and in rapidly growing differentiating and regenerating liver. Xanthine oxidase activity was measured in the supernatant fluid prepared by centrifugation of 5% homogenates at 100,000 X g for 30 min. There was no uricase activity in the supernatant fluid. The affinity of xanthine oxidase to xanthine was similar in normal liver and in slow- and rapidly growing hepatomas (Km=6 to 8 muM), and theoptimum pH was 8.0; at pH 7.4, the activity was 80% of that at the pH optimum. A standard assay was worked out for the liver and hepatoma systems; the enzyme activity was linear during 60-min incubation and proportionate with amounts of protein added over a range of 0.5 to 3.0 mg. Xanthine oxidase specific activity was 9 times higher in small intestine than in liver. Activities in lung, spleen, kidney, heart, testes, and thymus were 67, 59, 21, 19, 8, and 8%, and in skeletal muscle, brain, and bone marrow activities were 5% of that of the liver. In regenerating liver, xanthine oxidase activity was not changed from that of the liver of sham-operated controls up to 96 hr after operation. The activity of the average differentiating liver cell was less than 5% of that of adult liver during the first week after birth. At postnatal ages of 18, 25, 30 and 40 days, the activity rose to 18, 46, 76, and 94%, respectively, of that of the adult liver. In starvation, hepatic xanthine oxidase activity per cell was preferentially depleted as compared to the decline in protein concentration. Upon refeeding, the enzymatic activity was restored more slowly than the protein content. Since xanthine oxidase activity was decreased in all examined hepatomas, including the slowest-growing, well-differentiated neoplasms, the altered activity of this enzyme appears to be.linked with neoplastic transformatiobosyl 1-pyrophosphate amidotransferase (EC 2.4.2.14), was increassed in the hepatomas, the reprogramming of gene expression results in an imbalance that favors the synthetic over the catabolic potential. This enzymatic imbalance should confer selective advantages to the cancer cells.
Cancer Res 1976 Dec
PMID:Imbalance of purine metabolism in hepatomas of different growth rates as expressed in behavior of xanthine oxidase (EC 1.2.3.2). 18 29


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