Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Endotoxin was shown to depress neutrophil bactericidal activity while enhancing Nitro Blue Tetrazolium reduction and hexose monophosphate shunt activity. Separation of bactericidal action from oxidative metabolism suggests that the effect of endotoxin might involve the formation of reactive oxygen radicals such as superoxide. Chemiluminescence often accompanies metabolic activation of polymorphonuclear neutrophils (PMNs). However, human PMNs did not show chemiluminescence when challenged with endotoxin (lipopolysaccharide; LPS) or lipid A. Superoxide formation was also unaffected by endotoxin. In contrast, preincubation of PMNs with LPS for 30 min produced significant depression of chemiluminescence, oxygen consumption, and superoxide formation. Decreased chemiluminescence was not the result of complement consumption. In a cell-free system, superoxide was not scavenged by LPS, nor did LPS stimulate superoxide dismutase. Oxidase enzymes for reduced nicotinamide adenine dinucleotide or reduced nicotinamide adenine dinucleotide phosphate harvested from broken cells were not affected by LPS. The toxicity of LPS may reside in its ability to activate the PMNs while simultaneously blocking bactericidal capacity.
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PMID:Endotoxin in vitro interactions with human neutrophils: depression of chemiluminescence, oxygen consumption, superoxide production, and killing. 22 88

The specific activity of glutamine synthetase in cultured Chinese hamster cells is inversely related to the concentration of glutamine in the surrounding solution. Enzyme specific activity increases 8- to 10-fold when glutamine is removed from serum-free F12 growth media. The induction of glutamine synthetase activity occurs only after glutamine removal and not after the removal of other amino acids (methionine, leucine, or isoleucine). The analysis of the glutamine-mediated decrease in glutamine synthetase activity has been simplified by the finding that depression proceeds in nutrient-free buffered saline solution (141 mM NaCl, 5.4 mM KCl and 30 mM Tricine (pH 7.4). Under these conditions, 0.1 mM cyanide blocks glutamine-mediated depression. The cyanide inhibition is reversed by the addition of 1.0 mM glucose which suggests that ATP is required for depression. Glutamine-mediated depression is temperature-dependent, occurring between 25 and 45 degrees with an optimum rate at 37 degrees. Studies of the time course of induction and depression as a function of glutamine concentration suggest that glutamine regulates the rate at which the enzyme is either modified or degraded. We have employed an antibody prepared against homogeneous Chinese hamster liver glutamine synthetase to measure the amount of glutamine synthetase protein in extracts of cells containing induced or depressed levels of enzyme activity. A highly sensitive immunoprecipitation procedure enables quantitation of nanogram amounts of glutamine synthetase protein. Glutamine synthetase in cell extracts containing induced levels of enzyme activity possesses the same molecular specific activity (ratio of activity to antigenicity) as homogeneous Chinese hamster liver glutamine synthetase. The molecular specific activity of glutamine synthetase is almost the same in extracts of cells with depressed levels of enzyme obtained by growth for short (2 hours) and long (24 hours) times in the presence of glutamine. These data suggest that glutamine-mediated depression of glutamine synthetase results from degradation of enzyme molecules.
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PMID:Immunochemical evidence for glutamine-mediated degradation of glutamine synthetase in cultured Chinese hamster cells. 23 54

The properties of succinate uptake in succinate-grown Kluyveromyces cells were examined. The rate of succinate transport at 15C exhibits an approximate V-max of 1.2 mumol times h-1 times mg-1 dry weight of cells and an apparent K-m of 18 muM. The uptake process appears to be tightly coupled to metabolism. L-Malate, fumarate, and alpha-ketoglutarate were the only other dicarboxylates tested, which were found to inhibit succinate transport. The aggreement between the order of inhibition of succinate transport by these dicarboxylates and their rates of uptake, as well as the competitive nature of the inhibition are all consistent with the existence of a common carrier system showing specificity for dicarboxylates of the TCA cycle. Cells transferred from succinate to glucose medium rapidly lose their ability to transport succinate. Glucose-grown cells also exhibit an inability to oxidize dicarboxylates or to use them for growth without a very long lag. The dicarboxylate uptake system, therefore, appears to be subject to a strong catabolite repression. The depression of the succinate transport system requires the presence of succinate, as well as low concentrations of glucose.
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PMID:Dual effects of glucose on dicarboxylic acid transport in Kluyveromyces lactis. 23 57

Octanoate is avidly incorporated into triglycerides by isolated rat adipocytes in the presence of glucose via direct esterification without prior beta-oxidation to acetyl CoA. This was shown by separation of the products formed from (1-14C) octanoate into lipid classes using Florisil columns, and after alkaline hydrolysis of the triglyceride fraction, by cochromatogrpahy with authentic fatty acids on reverse-phase Celite columns. The relative contribution of (U-14C) glucose and (1-14C) octanoate to triglyceride synthesis and CO2 formation were studied under a variety of conditions. Concentrations of octanoate below 0.5 mM have a stimulatory effect on the conversion of (U-14C) glucose to CO2, triglycerides and esterified fatty acids. However, a marked depression of fatty acid synthesis from (U-14C) glucose was observed in the presence of millimolar concentrations of octanoate. Octanoate had no effect on the esterification of palmitate, but palmitate strongly depressed the ability of rat adipocytes to esterify octanoate.
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PMID:Metabolism of octanoate and its effect on glucose and palmitate utilization by isolated fat cells. 23 73

Stupor in patients with nonketotic hyperglycemia has been ascribed to hyperosmolarity, but the cause of depressed consciousness in patients with ketoacidosis has been puzzling. In this study, blood pH, serum glucose and sodium concentrations, and serum osmolality were measured in eighty-five consecutive episodes of diabetic ketoacidosis and forty-seven of nonketotic hyperglycemia. In the acidotic patients, as in those with nonketotic hyperglycemia, stupor closely paralleled hyperosmolarity and not the severity of acidemia. Indeed, the mean elevations of serum osmolarity were almost the same in the ketotic and in the nonketotic patients who were deeply obtunded. It seems likely that depression of consciousness in patients with severely uncontrolled diabetes mellitus, if not due to a nonmetabolic disorder, such as acute stroke, is attributable to hyperosmolarity, whether or not ketoacidosis is present.
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PMID:Hyperosmolar nature of diabetic coma. 23 99

Respiration and glycolysis of pig platelets suspended in a dialyzed plasma were studied at various hydrogen ion concentrations. Respiration of platelets was high at acidic pH and decreased at physiological pH. This pH profile may not be attributed to properties of mitochondria, since the respiratory rate of mitochondria prepared from platelets was maximal at physiological pH. A low respiratory rate at physiological pH seemed to be attributable to depression of respiration by glycolysis, since the addition of glucose further depressed the rate. The Crabtree effect was more prominent at alkaline ph. glycolysis increased with an increase in the pH of the plasma, contrary to oxygen comsumption. The Pasteur effect was less prominent at alkaline pH. The effect of pH on lactate production by the cytosol fraction of platelets was similar to that of whole platelets. The glycolytic intermediate pattern showed that phosphofructolinase was the committed step. Both ATP concentration and ATP formation calculated from respiratory and glycolytic rates were constant at various pH values. These observations may indicate that the pH primarily affects platelet glycolysis at the phosphofructokinase step and the respiration is secondarily controlled by glycolysis.
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PMID:Effect of hydrogen ion concentration on energy metabolism in pig platelets. 23 23

Studies in vitro and with intact chicks support the view that liver is the major site of lipid biosynthesis in the chicken. Adipose tissue is relatively unimportant as a site of fatty acid biosynthesis in this species although it does have the ability to esterify fatty acids to triglycerides. The available evidence, therefore, suggests that in the chicken, and presumably other avian species, fatty acids are synthesized in liver and are transported as triglycerides in the plasma low-density lipoproteins to the adipose tissue for storage. Fasting, even for short periods of time, markedly depresses the capacity for hepatic lipogenesis in the chick. Food restriction for 2 hr. depresses hepatic lipogenesis by about 90% and refeeding for 1 hr./or/the intravenous administration of glucose or fructose restores the lipogenic capacity. Feeding diets high in fat or protein cannot be adequately explained on the basis of the reduction of dietary carbohydrate which accompanies increased dietary protein or fat levels. Dietary fat and protein appear to exert their effects on hepatic lipid synthesis by different mechanisms. The depression in hepatic fatty acid synthesis brought about by fasting or fat-feeding is accompanied, and probably preceded, by an increased plasma free fatty acid level. Under these conditions hepatic fatty-acyl CoA levels increase while free CoA levels are reduced. Long-chain acyl CoA derivatives are capable of inhibiting acetyl CoA carboxylase activity as well as citrate transport. The reduced availability of free CoA may limit the citrate cleavage reaction. Dietary alterations influence the hepatic lactate-pyruvate ratio of chicks, however the changes observed are not always consistent with the changes observed in rat liver. Chicks fed high-protein diets have a decreased hepatic lactate/pyruvate ratio indicative of a more oxidized cytoplasmic environment. This change in redox state may be associated with control of fatty acid synthesis in chicks fed high-protein diets. Thyroxine and glucagon affect hepatic fatty acid synthesis in the chick, however insulin appears to play a lesser role.
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PMID:Lipid biosynthesis in the chick. A consideration of site of synthesis, influence of diet and possible regulatory mechanisms. 24 Jan 59

Human red cells were incubated at pH 8.2 and 30 mM phosphate concentration with glucose, glucose plus methylene blue, or inosine. In 16 normal subjects, the lactate production rate (LPR) from glucose alone was 92.2 +/- 7.5 mumoles per minute per liter red blood cell. With methylene blue added, the mean LPR was 118.5 +/- 7.4 per cent of control glucose values. With inosine as substrate the mean LPR was 68.5 +/- 6.0 per cent of that from glucose. Lactate/glucose ratios averaged 1.36, presumably because of accumulation of intermediates under conditions of high pH and Pi. Patients with various kinds of anemias had LPR's from glucose that were usually markedly higher than normal, but the LPR's from inosine were generally about 2/3 of those from glucose. The LPR's of the anemic patients correlated with their degree of reticulocytosis and several patients with pyruvate kinase (PK) deficiency showed normal LPR if the red cell population age was ignored, byt marked depression when compared to expected LPR for degree of reticulocytosis. The LPR from glucose of red cells of G6PD-deficient subjects was decreased (not increased) by methylene blue. Methylene blue, while stimulating the pentose phosphate pathway, also mediated some oxidation of NADH, thus complicating the stoichiometry of the overall system. In addition, the results suggested that the dye may have attacked -SH groups on some enzymes. In normal red cells, the lower LPR from inosine than from glucose was explained as due to consumption of ATP for hexose utilization (thus generating more ADP for the triose reactions). In confirmation, when red cells were incubated without substrate to deplete their ATP-, and enhance their ADP-, levels, the LPR from inosine exceeded that from glucose. Fluoride and iodoacetate affected LPR from glucose more than from inosine, suggesting the necessity of adequate ATP levels in hexose utilization. Overall glycolysis in the red cell is seen as the resultant of a network of metabolic reactions in which ADP and ATP levels are important control parameters.
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PMID:Incubation studies on human red cells utilizing glucose or inosine under various conditions. 24 Aug 98

These studies have been designed to test whether 1,3-butanediol (BD) alleviates milk fat depression in lactating cows, to observe physiological changes in blood and rumen constituents when BD is fed to cows or growing cattle, and to test the effects of BD on growth rates and feed efficiency in growing cattle. In trials with lactating cows, milk fat percentage and total fat production were higher for cows fed BD than for controls. Feeding BD to either cows or growing cattle had no consistent effect on rumen pH or relative concentrations of rumen volatile fatty acids. 1,3-Butanediol feeding had little effect on blood glucose concentrations. Feeding more than 4% BD in diets sometimes caused increased concentrations of blood ketones. In trials where growing cattle were fed 4% BD, rates of gain and feed efficiency were at least as good as and often better than those of cattle fed the same diets without BD. Body composition was not significantly affected. 1,3-Butanediol can be utilized effectively as an energy source for cattle and causes no obvious problems with 4% in diets.
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PMID:Use of 1,3-butanediol for lactation and growth in cattle. 24 68

Peritonitis in rats was produced by cecal ligation and puncture. Sixteen hours following cecal ligation and puncture, the gangrenous cecum was removed and the animals received either 4 ml saline (nontreated), 0.75 ATP-MgCl2 (100 mumoles ATP plus 50 mumoles MgCl2), and 2.0 ml of 50% glucose or 2.0 ml of 50% mannitol and 1.25 ml saline. Two hours after the removal of the cecum, RES function was evaluated by measuring the intravascular clearance of a 131 I triolein-labeled gelatinized test lipid emulsion. The intravascular half-time (t1/2) in the nontreated animals was double that of sham-operated animals, suggesting that significant depression in RES function occurred during sepsis. Administration of ATP-MgCl2 plus glucose following sepsis resulted in t1/2 values similar to those of sham-operated animals, indicating that the impairment of pagocytic activity of the RES was reversed with treatment. The beneficial effect of treatment following sepsis does not appear to be due to hypertonicity, since administration of 50% mannitol failed to decrease the t1/2. The precise mechanism of the beneficial effect of ATP-MgCl2 + glucose on restoration of RES function is not known.
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PMID:Impairment of reticuloendothelial system function with sepsis and its improvement with ATP-MgCl2 plus glucose administration. 26


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