Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.6.1.1 (aspartate aminotransferase)
21,665 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In an experimental study, employing anaesthetized dogs, it was investigated whether cellular enzymes from peripheral skeletal muscle get into the circulating blood by diffusion across capillary membranes or by lymphatic transport. In the experimental group 1, the animals were anaesthetized only. The plasma activities of the four enzymes measured--lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, creatine kinase--did not show any mentionable change during a time period of 6 h. In group 2 one hind limb of each animal was moved passively for 1 h. Alanine aminotransferase remained unchanged in plasma, the activities of the three other enzymes increased significantly. In group 3 one hind limb was made hypoxic by clamping the femoral blood vessels for 1 h. No activity changes were observed. When the period of hypoxia was followed by a 1-hour period of passive movement in group 4, the alterations in plasma activities were almost identical to those observed in group 2. In group 5 the experimental procedure was as in group 4, in addition the lymph from the thoracic duct was quantitatively withdrawn. The enzyme activities in plasma revealed a tendency to decrease rather than increase. Lymph flow increased significantly as well as the lymphatic activities of those enzymes which have high intracellular activities in muscle. The results prove, that enzymes from muscle are transported from the interstitial into the intravascular compartment mainly by lymphatic transport. Indications were found that the interruption of blood flow in one hind limb did not result in an enzyme release from muscle cells. It is discussed how changes in lymph flow, occurring during physical exercise for example, affect enzyme activities in plasma.
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PMID:Lymphatic transport of cellular enzymes from muscle into the intravascular compartment. 45 37

Oxamate, a potent inhibitor of lactate dehydrogenase, is shown also to inhibit aspartate aminotransferase activity, both in human serum and in purified isoenzymes of human origin. The inhibition was competitive with respect to 2-oxoglutarate for both isoenzymes. The apparent Ki was 29 mmol/L for the cytoplasmic enzyme and 17 mmol/L for the mitochondrial enzyme. Noncompetitive inhibition was found between oxamate and aspartate. At saturating concentrations of substrate (2-oxoglutarate greater than or equal to 15 mmol/L, L-aspartate greater than or equal 150 mmol/L) oxamate inhibited the mitochondrial enzyme but had less effect on the cytoplasmic isoenzyme. Oxamate at 40 mmol/L inhibited the enzyme in serum by 11 and 9% in assays containing 2-oxoglutarate at 6.7 and 15 mmol/L, respectively. This concentration of oxamate inhibited enzyme activity in serum by 5% more than did the same concentration of Cl- (itself an inhibitor). Oxamate (less than or equal to 30 mmol/L) had no measurable effect on the stability or activity of porcine malate dehydrogenase. Until the effects of its inhibitory properties are considered, addition of oxamate to suppress lactate dehydrogenase-mediated side reactions in the assay of aspartate aminotransferase cannot be recommended.
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PMID:Measurement of aspartate aminotransferase activity: effects of oxamate. 46 65

Sets of survey specimens having known linear interralationships were analyzed on four occasions by approximately 450 laboratories for the five enzymes lactate dehydrogenase, aspartate aminotransferase, creatine kinase, alanine aminotransferase, and alkaline phosphatase. The results are summarized in terms of the apparent precision and relative accuracy of various analytical systems, and some apparent problems in enzyme assays are identified. The results show that interlaboratory differences in enzyme analyses are not due primarily to differences in the way laboratorians utilize their analytical systems but rather are due to fundamental differences in the instruments and reagents supplied to the laboratorians. The attainment of interlaboratory comparability of enzyme analyses is a problem that can best be addressed by the manufacturers of instruments and reagents, rather than by individual laboratorians.
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PMID:The 1978 College of American Pathologists survey of analyses of five serum enzymes by 450 laboratories. 47 5

The 2-n-propyl (pr) and 2-n-butyl (bu) methylenedioxyindenes (MDIs) developed in our laboratories are intracellular calcium antagonists with coronary dilating and antiarrhythmic actions. Acute toxicity studies resulted, in mice, in an iv LD50 of 40 and 32 mg/kg for pr-MDI and bu-MDI, respectively, and an ip LD50 of 185 mg/kg for both MDIs. In rats, the ip LD50 was 175 and 240 mg/kg for pr-MDI and bu-MDI, respectively. An iv dose of 16 mg/kg decreased motor activity and prolonged barbiturate sleeping time in mice, but did not affect conditioned avoidance behavior or motor coordination tests. In sub-acute toxicity studies, rats received daily for 4 weeks 26.25 or 52.5 mg/kg ip of either MDIs, while mice received 23.13 or 46.25 mg/kg ip of either MDIs. No alterations were observed in serum alkaline phosphatase, glutamic-pyruvic transaminase, glutamic-oxalacetic transaminase, creatine phosphokinase, bilirubin, chloride, cholesterol, uric acid, prothrombin time, and bromsulphalein retention. Blood glucose was slightly lowered. Serum calcium was slightly lowered in male mice. The higher dose of pr-MDI elevated serum lactate dehydrogenase in rats. Both MDIs elevated serum isocitric dehydrogenase in male rats. Light microscopic examination of brain, kidney, liver, spleen, intestine, stomach, and myocardium showed no anomalies resulting from the 4-week MDI treatment, and electron microscopic examination of hepatocytes revealed no deleterious effects of either MDIs.
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PMID:Toxicological evaluation of new calcium antagonists: 2-substituted 3-dimethylamino-5,6-methylenedioxyindenes. 51 12

The methodology of a large prospective study on the influence of repeated anaesthetics on liver function is reported and the problems involved are discussed. The most suitable patients were those presenting for endoscopic examination of the bladder and urethra, for urethral dilatation and for cervical implantation of radium. Blood samples were taken immediately before induction of anaesthesia and on days 3-4 and 13-15 after operation, when a clinical assessment of the patient was also carried out. The concentrations of six enzymes (lactate dehydrogenase, alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, serum cholinesterase and gamma glutamyl transpeptidase) werechosen specifically as indices of liver function. The eosinophil count was measured to reflect any hypersensitivity reaction. The non-Gaussian distribution of these necessitated using appropriate non-parametric tests together with parametric tests on logarithmic transformed data. In addition a quantal method was used to measure the frequency of patients showing an "abnormal" increase in enzyme concentrations.
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PMID:Methodology of a prospective study of changes in liver enzyme concentrations following repeat anaesthetics. 52 78

A radioimmunoassay for quantitation of serum myoglobin in healthy individuals and patients with different diseases is described. Purified myoglobin was labelled by an 125I-labelled ester (N-succinimidyl 3-(-4 hydroxy, 5-[125I]iodophenyl) propionate), a commercially available antiserum was used, and the antigen-antibody complex was precipitated with polyethylene glycol 6000. The rapid assay can be performed within 1 h at 37 degrees C with a detection limit of 45 micrograms/l. Prolonged incubation at 4 degrees C for 18 or 72 h gives a detection limit of 6 and 2 micrograms/l, respectively. The mean coefficient of variation of the routine assay was 11%. In healthy human subjects a significant difference in mean serum myoglobin concentration was found between 43 women (34 +/- 17 micrograms/l) and 51 mean 47 +/- 15 micrograms/l). In twenty patients admitted to hospital with the clinical diagnosis acute myocardial infarction, the serum myoglobin concentration profiles were in close agreement with the final diagnosis. In three patients with myocardial infarction serum samples were taken every 2 h after the acute episode, and serum myoglobin levels were compared with the levels of creatine kinase, lactate dehydrogenase, aspartate aminotransferase and creatine kinase isoenzyme-MB.
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PMID:Rapid and sensitive radioimmunoassays for human myoglobin. 53 83

A study of cardiovascular risk factors in middle-aged twin men provided an opportunity to test for genetic variability in the SMA 12/60 (Technicon) battery of clinical chemistry tests. Classical twin methodology was used to analyze the variation of monozygotic and dizygotic twins. In addition, frequency of co-twin contact was used to control for effects of differences in shared environment. Genetic variability played a definite role in controlling four of the 11 reported tests: one-hour serum glucose, serum urea nitrogen, uric acid, and bilirubin. No genetic variation was found for lactate dehydrogenase, phosphorus, and alkaline phosphatase. Significantly higher means for calcium, total protein, albumin, and aspartate aminotransferase in monozygotic twins precluded any statement about heredity and environment for these tests.
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PMID:Genetic variability of clinical chemical values. 55 78

Vitamins A, E and K were incorporated into turkey starter rations at normal (1 x ), 5 x and 50 x the National Research Council recommended vitamin levels and evaluated for their effect on histomoniasis in turkeys. Infected as well as comparable unifected poults were included in all trials. Each vitamin was also evaluated at normal and 50 x the NRC level in combination with ipronidazole, a low-level antihistomonal agent. In addition to performance parameters, glutamate oxaloacetate transaminase (GOT) and lactate dehydrogenase (LDH) plasma enzyme levels were used to evaluate the vitamin effect. None of the vitamins tested alone were found to be effective in terms of reducing mortality and morbidity following a severe Histomonas meleagridis challenge, regardless of the vitamin dose. A significant improvement in performance was demonstrated with the vitamin E (50 X)--ipronidazole combination and a numerical improvement with the vitamin A (50 X)--ipronidazole combination over ipronidazole alone or the poults fed NRC recommended vitamin levels. The GOT and LDH plasma enzyme levels correlated well with the progressive pathological changes associated with the disease. At 11 days post-infection both enzymes were consistently and significantly elevated above those of the uninfected controls, irrespective of the vitamin levels provided. The presence of low ipronidazole in most instances delayed the onset of clinical symptoms and was associated with a delay in enzyme elevation, indicating the excellent correlation and sensitivity of the enzyme method in assessing liver damage.
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PMID:The effect of vitamins A, E and K on experimentally induced histomoniasis in turkeys. 57 Feb 65

The activities of hexokinase, glucose-6-phosphate dehydrogenase, and glycolytic enzymes were higher in the fetal myocardium of the guinea pig than at birth and fell progressively during the 1st mo of life. The alphaHBDH/LDH ratio of H to M subunits of lactate dehydrogenase, was low in the fetus and continued to rise during the 1st mo after birth. The distinction between the left and right ventricular activities of lactate dehydrogenase, which is clear in adult guinea pigs, was absent in the fetus and appeared during postnatal development. Glycogen phosphorylase activity was low in the fetus and at birth. The activities of beta-hydroxyacylcoenzyme A dehydrogenase, succinate dehydrogenase, malate dehydrogenase, and aspartate aminotransferase were low in the fetus, but had reached, or even temporarily exceeded, normal adult levels at birth. Palmitylcarnitine transferase activity was also low in the fetal heart compared with the newborn but continued to increase substantially during the first 2 wk after birth.
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PMID:Myocardial enzyme activities in guinea pigs during development. 59 69

Blood serum of pygmy goats (both sexes, and castrated males) was analyzed to establish biochemical reference values. Influence of age on reference values was also studied. Serum biochemical analyses were made for urea nitrogen, creatinin, bilirubin, lactate dehydrogenase, aspartate aminotransferase, alkaline phosphatase, glucose, uric acid, and total lipids. These serum values for pygmy goats were similar to those reported for man, except as follows: Aspartate aminotransferase activities were slightly higher than those reported for man. Glucose concentrations in pygmy goats were slightly lower than in human beings, and uric acid levels were significantly lower than the values for man. Female and castrated male goats had lower total lipid concentrations than did human beings, whereas intact males had higher concentrations. Thus, of the 9 measured variables for pygmy goats, 5 were comparable to human values. This, together with other attributes, including the small size which conduces to economics of maintenance and enhances the desirability of using pygmy goats in research.
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PMID:Serum biochemistry values in normal pygmy goats. 59 8


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