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)

Individual enzyme-inhibitor complexes with characteristic absorption spectra have been obtained as a result of the reaction of the apoenzyme of aspartate aminotransferase with Nalpha-(5'-phosphopyridoxyl)-L-glutamic acid, Nalpha-(5'-phosphopyridoxyl)-D-glutamic acid, and Nalpha-(5'-phosphopyridoxyl)-L-pyroglutamic acid. The stability of the enzyme-inhibitor complexes has been investigated under various conditions, viz., reactivation by the coenzyme, denaturation by urea, variations in the pH. It has been shown that the complexes formed by the last two inhibitors are reactivated by pyridoxal-5'-phosphate and that the inhibitor can be released under mild conditions. The enzyme-inhibitor complex formed by Nalpha-(5'-phosphopyridoxyl)-L-glutamic acid, on the other hand, was not reactivated by the coenzyme. Pyridoxylglutamic acid has been isolate in attempts to release the inhibitor. The dephosphorylation of the inhibitor has been associated both with the hydrolysis of a phosphate bond involving the enzyme and with the phosphorylation of aspartate aminotransferase. A 32P peptide containing 13 amino acids has been isolated from the tryptic hydrolysate of the enzyme-inhibitor complex (formed by a 32P inhibitor). The data obtained have been interpreted on the basis of an assumption that the phosphate group of the coenzyme has an active role in the enzymatic transamination reaction.
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PMID:Labilization of the phosphoester linkage in enzyme-inhibitor complexes of aspartate aminotransferase. 1 13

Toxicosis was induced in pregnant Holstein-Friesian heifers by giving polybrominated biphenyls a in gelatin capsules at the rate of 25 g/day. Initially, this dosage was approximately 67 mg/kg of body weight. Clinical signs were anorexia, excessive lacrimation and salivation, diarrhea, emaciation, dehydration, depression, and abortion. Fever was not evident during the experiment. Values for serum glutamic-oxalacetic transaminase, lactic dehydrogenase, blood urea nitrogen, and bilirubin were increased. Changes in packed cell volume, hemoglobin content, total erythrocyte and leukocyte counts, and differential leukocyte counts were minimal and reflected dehydration and secondary infection. The principal urine changes were decreased specific gravity and moderate proteinuria. Gross necropsy findings included dehydration; subcutaneous emphysema and hemorrhage; atrophy of the thymus; fetal death with concomitant necrosis of cotyledons; kidneys that were enlarged, pale tan to gray; thickened wall of the gallbladder; inspissated bile; edema of abomasal folds; mucoid enteritis; linear hemorrhage and edema of the rectal mucosa; and secondary pneumonia. Microscopic changes were most marked in the kidneys, gallbladder, and eyelid. In the kidney, the principal changes were extreme dilatation of collecting ducts and convoluted tubules, with epithelial degenerative changes of cloudy swelling, hydropic degeneration, and separation from the basement membrane. Common changes in the gallbladder were moderate to marked hyperplasia and cystic dilatation of the mucous glands in the lamina propria. The changes in the eyelids were characterized by hyperkeratosis, with accumulations of keratin in hair follicles of the epidermis and squamous metaplasia with keratin cysts in the tarsal glands. Clinical signs and lesions of toxicosis did not develop in heifers given the polybrominated biphenyls at the rate of 0.25 mg and 250 mg/day for 60 days. Initially these rates were approximately 0.00065 mg/kg and 0.65 mg/kg of body weight, respectively.
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PMID:Pathology of experimentally induced polybrominated biphenyl toxicosis in pregnant heifers. 18 92

Humans are exposed to a number of toxic elements in the environment; however, most experiments with laboratory animals investigate only one toxic element. To determine if concomitant exposure to lead (Pb), cadmium (Cd), and/or arsenic (As) modified the changes produced by any one metal in various parameters of toxicity, 168 male, Sprague-Dawley, young adult rats were fed nutritionally adequate diets to which had been added 0 or 200 ppm Pb as Pb acetate, or 50 ppm Cd as Cd chloride, or 50 ppm As as sodium arsenate or arsanilic acid in a factorial design for a period of 10 weeks. At these concentrations, Cd and As reduced weight gain even when differences in food intake were taken into account; administration of both Cd and As depressed weight gain more than did either metal alone. Pb did not adversely affect food consumption or weight gain. Increased numbers of red blood cells (RBCs) were observed following administration of Pb, Cd, or As; usually more cells were observed when two or three metals were administered, compared to individual metals. Despite increasing numbers of circulating RBCs, hemoglobin and hematocrit were reduced, especially with the Pb-Cd combination and the Cd-arsanilic acid combination. Specific effects of Pb on heme synthesis were observed, including increased urinary excretion of delta-aminolevulinic acid; this increase was reduced by the presence of dietary cadmium. Analyses of blood showed values for the laboratory rat within normal ranges for blood urea nitrogen, creatinine, cholesterol, calcium, albumin, total protein, and bilirubin. Uric acid was increased by Pb, with little modification by dietary Cd or As content. Serum glutamate-oxalate transaminase activity was reduced by As. Serum alkaline phosphatase was greatly reduced by either As or Cd but not Pb. Combinations of As and Cd did not further reduce the activity of this enzyme. Kidney weight and kidney weight/body weight ratios were increased by Pb alone, with no effects of Cd or As alone or as interactions. Liver weight/body weight ratios were reduced in animals fed 50 ppm dietary Cd. Kidney histology shows predominantly Pb effects, namely, intranuclear inclusion bodies and cloudy swelling. Ultrastructural evaluation of kidneys from Pb-treated animals disclosed nuclear inclusion bodies of the usual morphology and mitochondrial swelling. Concurrent administration of Cd greatly minimized Pb effects on the kidney under conditions of this experiment. Liver histology suggests an increased rate of cell turnover with either As compound, but few specific changes.
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PMID:Effects of concurrent administration of lead, cadmium, and arsenic in the rat. 19 3

Toxicosis was induced in pregnant heifers by feeding 25,000 mg/head/day of FireMaster BP-6, a commercial blend of polybrominated biphenyls (PBB). The PBB feeding decreased dry matter intake approximately 50% by 4 days exposure. Emaciated animals became anorexic a few days prior to death at 33 to 66 days. Weight losses of heifers average 80 kg. Other clinical signs observed were dehydration, diarrhea, excessive salivation and lacrimation, fetal death, abortion, and general depression as evidenced by depressed heart and respiratory rates. Clinical signs were apparent after 10 days exposure and progressively intensified along with loss of condition until death. Clinicopathologic changes included significantly increased serum glutamic-oxaloacetic transaminase and decreased serum calcium by 30 days exposure. Lactate dehydrogenase, urea nitrogen, and bilirubin were elevated, and serum albumin decreased by 36 to 40 days. Principal urine changes were decreased specific gravity and moderate proteinuria. Pregnant heifers fed 0.25 or 250 mg/head/day for 60 days and nonpregnant heifers fed 250 mg/head/day for 180 days displayed neither clinical signs nor clinicopathologic changes indicating adverse effects from PBB exposure. Post-exposure, all heifers exposed to PBB for 60 days calved normally with zero calf mortality and were successfully rebred. Milk production was not different from control animals. Birth weights of calves from dams exposed to 250 mg PBB/head/day were significantly greater than calves of dams exposed to 0 mg or 0.25 mg/head/day. PBB exposure of dams produced no detrimental effects on calves as indicated by clinical signs, clinicopathologic changes, or performance.
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PMID:Effects of PBBs on cattle. I. Clinical evaluations and clinical chemistry. 21 5

Isolated rat livers were perfused at 35 degrees C with bovine serum albumin (40 g/l) in Krebs Ringer bicarbonate buffer, or with the same solution containing insulin (0.22 x 10(-6) mol/l), hydrocortisone (0.068 x 10(-3) mol/l), or both hormones together. Observations on the synthesis of bile and on perfusate levels of potassium, aspartate aminotransferase, urea and glucose showed that the presence of insulin and/or hydrocortisone had no beneficial effect on the perfused rat liver in vitro. There is little justification of the isolated liver.
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PMID:The effect of insulin and hydrocortisone on the isolated rat liver. 28 8

Perfused livers isolated from rats under halothane anaesthesia produced greater amounts of bile, released smaller amounts of aspartate aminotransferase, and had a much greater ability to maintain a constant concentration of glucose in perfusates than those obtained with ether or pentobarbitone. Little or no effect was shown on the ability of the liver to synthesize urea and to retain potassium within the organ. It appears, therefore,that halothane is the anaesthetic of choice when removing the liver from the laboratory rat.
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PMID:Isolated liver perfusion: the choice of anaesthetic. 29 68

A safety evaluation of Aspergillus fumigatus I21, grown in a cassava carbohydrate and salts medium, was undertaken. Male weanling rats were fed the fungus at 20, 30 and 40% of the diet for 90 days. A control group was given soybean oil meal as the sole source of protein. Weekly determinations of the body weights and feed consumptions were made. A few days prior to termination of the feeding study, a kidney function test was undertaken on the rats. At the end of the feeding period hematology, blood biochemistry, urine analyses and histopathology studies of various tissues were carried out, and organs were weighed. Rats fed A. fumigatus I21 gained less weight than the controls, but kidney weights were increased. Increases in serum alkaline phosphatase and glutamic-oxaloacetic transaminase were not related to dose level. The blood urea nitrogen was increased for the rats fed 40% of the fungus. Rats fed 30 and 40% of the fungus I21 showed a significant drop in albumin. Deficiency in methionine or other essential amino acids through a limited feed consumption may have caused a decrease in albumin synthesis. Rats fed the highest level of the fungus showed increases in neutrophils and monocytes concomitant with decreases in lymphocytes and eosinophils which may be a response to stress. The urine analyses did not reveal any significant differences. The test rats were capable of concentrating urine adequately when deprived of water for 24 hours. No significant differences between the control and experimental groups were found by histopathological examinations.
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PMID:Safety evaluation of Aspergillus fumigatus grown on cassava for use as an animal feed. 33 62

The effects of three widely spaced levels of bacterial contamination of reagent water on several chemistry, radioimmunoassay, and coagulation procedures were studied. These included determinations of lactate dehydrogenase, creatine kinase, aspartate transaminase, alkaline phosphatase, blood urea nitrogen, total protein, thyroid-stimulating hormone, digoxin, thrombin time, activated partial thromboplastin time, and prothrombin time. Statistical analyses included calculations of means and coefficients of variation, and analysis of variance, as well as correlation coefficients for test results versus logarithm of bacterial contamination. Statistically and clinically significant differences occurred together only for an elevated level of creatine kinase.
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PMID:Effects of bacterial contamination of reagent water on selected laboratory tests. 43 36

Normal values for 13 chemical constituents of plasma were estimated from results for 837 presumably healthy children. Ninety microliters of specimen was analyzed for lactate dehydrogenase, aspartate aminotransferase, alkaline phosphatase, inorganic phosphorus, total calcium, total cholesterol, total proteins, albumin, uric acid, urea nitrogen, alanine aminotransferase, total bilirubin, and glucose. We used two Abbott ABA-100 Bichromatic Analyzers interfaced directly to the ABA Data Management System. For each test age- and sex-related variations were assessed and normal values were estimated for six different age groups.
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PMID:Microchemical analysis for 13 constituents of plasma from healthy children. 43 35

In order to verify the influence of sampling time on blood constituents, populations of supposedly healthy subjects were grouped according to age, sex, deviation from their ideal weight, state of fasting or nonfasting, and time of sampling. Each fasting subject in one group underwent two samplings during the course of a morning: the first at 08.00 and the second between 09.00 and 12.00. In the second group, the first was taken at 13.00, and the second between 14.00 and 16.00. Subjects in the second group had eaten a standard meal of 700 calories at 12.00. Differences between the paired samples from a given individual are discussed with respect to the time of sampling for plasma urea, creatinine, proteins, albumin, calcium, sodium, potassium, cholesterol, uric acid, chloride ions, phosphate, bilirubin, aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, creatine phosphokinase, alkaline phosphatase, hemoglobin and erythrocyte and leukocyte counts. Variations due to the time of sampling were large for phosphorus, bilirubin, and leukocyte count.
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PMID:The effect of sex, deviation from ideal weight and sampling time on blood constituents in presumably healthy subjects. 43 75


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