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 this study, we examined whether the production of hydrogen peroxide by peroxisome proliferators causes oxidative DNA damage in the form of 8-oxodeoxyguanosine (8-oxodG) and hepatic injury, and whether it is related to their tumor-promoting or carcinogenic activities in female rats treated with the peroxisome proliferators clofibrate and perfluorodecanoic acid (PFDA). Clofibrate has tumor-promoting and carcinogenic activities, whereas PFDA does not. We also tested whether peroxisome proliferators directly induce mutagenic events in Salmonella typhimurium strains TA 98 and TA 1537. Rats were treated either by 5% clofibrate in diet or by an i.p. injection of corn oil containing 10 mg/kg body weight of PFDA every week for 2 or 8 weeks. 8-OxodG in liver DNA was analyzed by HPLC coupled with an electrochemical detector. Hepatic injury was evidenced by liver enlargement and by levels of serum enzymes, aspartate aminotransferase (AST) and alanine aminotransferase (ALT), and hepatic gamma-glutamylpeptidase (gamma-GT) activity. Clofibrate and PFDA increased the activity of catalase about or less than 2-fold, whereas FAO activity was increased about 6 to 7-fold by clofibrate and about 3 to 4-fold by PFDA. Neither clofibrate nor PFDA induced mutation at any dose tested. Clofibrate significantly increased the formation of 8-oxodG, but PFDA only slightly increased. Serum AST and ALT levels, and hepatic gamma-GT activity were not significantly changed at both time points, whereas the ratio of liver/body weight was significantly increased by clofibrate and PFDA at 8 weeks. These data imply that the magnitude of the production of hydrogen peroxide-generated FAO is related to the induction of oxidative DNA damage by peroxisome proliferators, and their tumor-promoting or carcinogenic activities. However, the effect of hydrogen peroxide in hepatic injury is not clear.
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PMID:Formation of 8-oxodeoxyguanosine in liver DNA and hepatic injury by peroxisome proliferator clofibrate and perfluorodecanoic acid in rats. 964 51

Age-associated changes in liver injury and post-necrotic regeneration were studied in rats aged 6 and 30 months in a period of 96 h following a dose of thioacetamide (6.6 mmol/kg body weight). Hepatocellular necrosis was detected in both groups by serum aspartate aminotransferase, but the severity of injury was significantly lower (one fourth, p < 0.001) in the oldest. Differences were observed in hepatocyte FAD monooxygenase activity between 6 and 30 months old rats at 24 h (278 versus 170%, p < 0.001, respectively) and also in GSH/GSSG ratio, in protein thiol groups and in malondialdehyde. Glutathione peroxidase, glutathione reductase and glucose-6-phosphate dehydrogenase activities rose markedly in both groups, this increase being slightly lower in the oldest. Superoxide dismutase and catalase did not show significant changes between both groups. At the end of the 96 h experimental period the restoration towards normal of GSG/GSSG, protein thiols malondialdehyde and the activities of Cu-Zn superoxide dismutase and catalase were significantly lower in hepatocytes from 30 months old rats. We summarize that the main age-related changes in the sequenced process of liver injury and regeneration occurred to a lesser extent in severity of injury and delayed response in the post-necrotic restoration of liver function, probably due to a lower increase in antioxidant enzyme system.
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PMID:Aging delays the post-necrotic restoration of liver function. 969 17

Total superoxide dismutase (SOD, EC 1.15.1.1) and catalase (CAT, EC 1.11.1.6) activities in erythrocytes and the glutamic acid-oxalacetic acid-transaminase (GOT, EC 2.6.1.1) and glutamic acid-pyruvic acid-transaminase (GPT, EC 2.6.1.2) activities in the plasma were measured in experimental groups of carps (Cyprinus carpio L.) exposed to cadmium in a concentration of 20 mg Cd/l water under aquarium conditions for 6, 12, 18 and 24 hours and in control fishes. It was shown that the total activity of SOD in the erythrocytes is significantly decreased after 12, 18 and 24 hours of cadmium exposure. Increased activities of CAT (after 24 hours) in the erythrocytes and GOT and GPT in the plasma were found in cadmium-treated fishes. At the same time the concentration of blood haemoglobin and haematocrit values were significantly diminished. These results indicate that cadmium causes oxidative stress and tissue damage in the exposed fishes.
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PMID:Activities of superoxide dismutase and catalase in erythrocytes and transaminases in the plasma of carps (Cyprinus carpio L.) exposed to cadmium. 972 86

The purpose of our study was to assess the effects of experimental dicroceliosis on the antioxidant defense capability of the liver in hamsters. Studies were carried out at 80 and 120 days after infection with an oral dose of 40 metacercariae of Dicrocoelium dendriticum. The parasitic pathology was ascertained by the presence of fluke eggs in feces, increased serum ALT and AST activities, and histological findings. The concentration of thiobarbituric acid-reactive substances (TBARS) and the ratio of oxidized to reduced glutathione (GSSG/GSH), measured as markers of oxidative stress, were significantly increased [TBARS: +40% and +84% at 80 and 120 days postinfection (p.i.), respectively; GSSG/GSH: +200% and +117%]. Dicroceliosis increased Se-dependent glutathione peroxidase (GPx) activity in both cytosol (+24% and +46%) and mitochondria (+73% and +41%). Superoxide dismutase activity was significantly reduced in cytosol (-19% and -38%) and mitochondria (-20% and -39%). No significant change was found in the activity of Se-independent GPx or catalase. The ratio of glutathione peroxidase/glutathione reductase at 80 and 120 days p.i. was increased by 25% and 63%, respectively. Gamma-glutamyl cysteinyl synthetase activity was increased by 27% and 20%, respectively. Our data indicate that although dicroceliosis courses with activation of antioxidant enzymes and glutathione synthesis, inefficient scavenging of reactive oxygen species takes place, resulting in oxidative liver damage.
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PMID:Oxidative stress and changes in liver antioxidant enzymes induced by experimental dicroceliosis in hamsters. 1034 40

Somatic mutations in the transforming growth factor beta receptor type II (TGF-beta RII) gene have been observed in various human cancers showing microsatellite instability. Most of the mutations observed were additions or deletions of the mononucleotide repeat sequence present in TGF-beta RII coding region, suggesting that the TGF-beta RII may be a target gene of genomic instability in tumorigenesis. Recently, we reported germ-line frameshift mutations in the mononucleotide repeat sequence of the hMSH6 gene, which is believed to be one of the target genes of genomic instability in tumorigenesis, suggesting the possibility of germ-line mutation in mononucleotide repeat sequences. Moreover, one case of germ-line mutation in the TGF-beta RII gene was identified in a hereditary nonpolyposis colorectal cancer (HNPCC) kindred, indicating the involvement of TGF-beta RII inactivation in tumorigenesis of HNPCC. However, germ-line mutation analysis of all of the coding sequences and the mononucleotide repeat sequence of the TGF-beta RII in HNPCC patients has not yet been fully elucidated. Therefore, to further investigate the presence of germ-line mutations, we screened all of the coding region sequences and mononucleotide repeat sequence of TGF-beta RII from 35 HNPCC, 44 suspected HNPCC, and 45 sporadic early-onset colorectal cancer patients. However, no pathogenic mutations other than silent mutations, introgenic mutation, and polymorphisms were identified. Two silent mutations at codons 309 (ACG to ACA) and 340 (CAT to CAC) in the kinase domain located in exon 4 were detected. A 1-bp cytidine deletion was observed 6 bases from the 3' end of intron. Two polymorphisms were identified at codon 389 (AAC to AAT) and at the fourth-to-last base in intron 3. The polymorphism at codon 389 was more frequent in HNPCC (20%; 7 of 35) and suspected HNPCC patients (18%; 8 of 44) than in nonmalignant control group (10%; 5 of 50). Moreover, the frequency was significantly higher in early-onset colorectal cancer patients (31%; 14 of 45). This is the first report of a different frequency of polymorphism in HNPCC, suspected HNPCC, early-onset colorectal cancer patients, and healthy normal individuals. This result suggests that: (a) germ-line mutation of the TGF-beta RII gene may be a rare event during tumorigenesis in HNPCC and sporadic early-onset colorectal cancer; (b) the mononucleotide repeat sequence of the TGF-beta RII gene is an apparent target of genomic instability but not of germ-line mutation; and (c) the polymorphism of codon 389 (AAC to AAT) is frequent, especially in early-onset colorectal cancer patients, in which it is more frequent than in control group.
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PMID:Mutational analysis of the transforming growth factor beta receptor type II gene in hereditary nonpolyposis colorectal cancer and early-onset colorectal cancer patients. 1069 May 36

The effects of thymoquinone (TQ) and desferrioxamine (DFO) against carbon tetrachloride (CCl4)-induced hepatotoxicity were investigated. A single dose of CCl4 (20 microl/kg, i.p.) induced hepatotoxicity, manifested biochemically by significant elevation of activities of serum enzymes, such as alanine transaminase (ALT, EC: 2.6.1.2) , aspartate transaminase (AST, EC: 2.6.1.1) and lactate dehydrogenase (LDH, EC: 1.1.1.27). Hepatotoxicity was further evidenced by significant decrease of total sulfhydryl (-SH) content, and catalase (EC: 1.11.1.6) activity in hepatic tissues and significant increase in hepatic lipid peroxidation measured as malondialdhyde (MDA). Pretreatment of mice with DFO (200 mg/kg i.p.) 1 h before CCl4 injection or administration of TQ (16 mg/kg/day, p.o.) in drinking water, starting 5 days before CCl4 injection and continuing during the experimental period, ameliorated the hepatotoxicity induced by CCl4, as evidenced by a significant reduction in the elevated levels of serum enzymes as well as a significant decrease in the hepatic MDA content and a significant increase in the total sulfhydryl content 24 h after CCl4 administration. In a separate in vitro assay, TQ and DFO inhibited the non-enzymatic lipid peroxidation of normal mice liver homogenate induced by Fe3+/ascorbate in a dose-dependent manner. These results indicate that TQ and DFO are efficient cytoprotective agents against CCl4-induced hepotoxicity, possibly through inhibition of the production of oxygen free radicals that cause lipid peroxidation.
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PMID:Protective effects of thymoquinone and desferrioxamine against hepatotoxicity of carbon tetrachloride in mice. 1088 36

In the past decade it became accepted that free radicals, lipid peroxidation and antioxidant defense play a role in various tissues damages, thus in certain liver diseases as well. Since only limited data have been reported concerning the oxidative stress in viral hepatitis, a comparative study was performed in patients (pts) with chronic hepatitis C and alcoholic liver disease. In addition, the effects of a flavonolignan drug silymarin were assessed. 10 pts with chronic hepatitis C, 5 pts with alcoholic hepatitis and 13 pts with alcoholic cirrhosis have been investigated. Biochemical liver tests (serum bilirubin, aminotransferases, ALT, AST, lactate dehydrogenase (LDH), pseudocholinesterase, prothrombin), malandialdehyde (MDA) levels in plasma and red blood cell (RBC) hemolysate, superoxide radical generating capacity of stimulated polymorphonuclear granulocytes (PMN), plasma concentrations of reduced (GSH) and oxidized (GSSG) glutathione, vitamin A, luteine and beta carotene, furthermore RBC superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase activities were determined. The level of plasma MDA--as the marker of lipid peroxidation--was highest in alcoholic cirrhosis (five times of normal) (p < 0.05), the RBC hemolysate MDA was most elevated in chronic hepatitis C (p < 0.05). The mean PMNs' superoxide radical generating capacity was 116.6% of normal control in alcoholic hepatitis, where the mean GSH level was the lowest (89.8% of normal). Plasma vitamin A content was lowest in alcoholic cirrhosis (68% of control) (p < 0.05). SOD activity was elevated in both chronic hepatitis C and alcoholic cirrhosis, where GPx activity was decreased (p < 0.05). There was a correlation between LDH and SOD activities (r = 0.77, p = 0.015). Silymarin treatment of one month duration resulted in normalization of serum bilirubin in 55% of treated pts, AST became normal in 45%, and RBC hemolyzate MDA level normalized in similar rate. A significant increase in both GSH and retinoids was found. Alterations in oxidative stress and antioxidant defense system were shown in chronic hepatitis C, not only in alcoholic liver disease. The parameters of lipid peroxidation and antioxidant defense may be useful surrogate markers for monitoring pts with liver disease during hepatoprotective treatment.
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PMID:[Oxidative stress and antioxidant defense in alcoholic liver disease and chronic hepatitis C]. 1096 2

This review addresses the general hypothesis that the pathogenesis of preeclampsia and eclampsia are related to an imbalance of increased oxidative stress and lipid peroxidation coupled with a deficiency of antioxidant protection. Accordingly, this study was initiated to assess total antioxidant status and free-radical activity in preeclampsia and eclampsia. The patients studied were 44 healthy pregnant women and 45 women with hypertension classified as having preeclampsia (n=27), and eclampsia (n=18). The serum levels of lipid peroxide were significantly increased (p<0.0001) and antioxidant enzyme activities (superoxide dismutase and glutathione levels) in erythrocytes were significantly decreased (p<0.0001) in women with preeclampsia and eclampsia compared with the controls. The groups of preeclampsia and eclampsia had similar values of catalase activities as the controls (p>0.05). There were no correlations between serum levels of lipid peroxide and antioxidant enzyme activities or systolic-diastolic blood pressure of pregnant women with preeclampsia and eclampsia. The mean systolic and diastolic blood pressure, the serum lactate dehydrogenase (LDH) and aspartate transaminase (AST) levels of preeclamptic and eclamptic women were high, whereas haemoglobin (Hb), Hematocrit (Htc) and platelet levels were lower than those of the control subjects (p<0.0001). There were no differences in mean gestational week, whereas the mean age of eclamptic women was lower than that of the other two groups (p<0.001). The serum levels of Alanine-transaminase (ALT) and urea in eclamptic women were significantly higher compared with the other two groups (p<0.0001), whereas creatinine levels were lower than those of the other two groups (p<0.05). Our findings give support to those few studies considering lipid peroxidation as an important factor in the pathogenesis of preeclampsia and eclampsia. Further studies are needed to clarify the relations between lipid peroxidation and antioxidative function and their pathophysiological significance in preeclampsia and eclampsia.
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PMID:Significance of changes in lipid peroxides and antioxidant enzyme activities in pregnant women with preeclampsia and eclampsia. 1096 57

In the present study, the genotoxic, hematoxic effects, and their relation with pathological and biochemical parameters of hexane were investigated. Cytogenetic evaluation performed on the bone marrow indicated that chromosome aberrations increased at both hexane doses in relation to the negative controls. Decreased hematocrit, hemoglobin concentrations, and mean corpuscular volume were observed on the whole blood counts. Conjugated dienes (CD), glutathione (GSH), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and catalase (CAT) were increased. Histological examinations showed intracytoplasmic vacuolisation, nuclei with lower chromatin, and parenchymatous degenerations in the dose groups. In the bone marrow slides, depletion of the erythroid series were observed. In conclusion, hexane seems to be a genotoxic and hematoxic agent leading to degeneration and lipid peroxidation in exposed groups.
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PMID:Genotoxic, hematoxic, pathological, and biochemical effects of hexane on Swiss albino rats. 1107 17

In light of evidence that some complications of diabetes mellitus may be caused or exacerbated by oxidative damage, we investigated the effects of subacute treatment with the antioxidant quercetin on tissue antioxidant defense systems in streptozotocin-induced diabetic Sprague-Dawley rats (30 days after streptozotocin induction). Quercetin, 2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxy-4H-1-benzopyran-4-one, was administered at a dose of 10mg/kg/day, ip for 14 days, after which liver, kidney, brain, and heart were assayed for degree of lipid peroxidation, reduced and oxidized glutathione content, and activities of the free-radical detoxifying enzymes catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase. Treatment of normal rats with quercetin increased serum AST and increased hepatic concentration of oxidized glutathione. All tissues from diabetic animals exhibited disturbances in antioxidant defense when compared with normal controls. Quercetin treatment of diabetic rats reversed only the diabetic effects on brain oxidized glutathione concentration and on hepatic glutathione peroxidase activity. By contrast, a 20% increase in hepatic lipid peroxidation, a 40% decline in hepatic glutathione concentration, an increase in renal (23%) and cardiac (40%) glutathione peroxidase activities, and a 65% increase in cardiac catalase activity reflect intensified diabetic effects after treatment with quercetin. These results call into question the ability of therapy with the antioxidant quercetin to reverse diabetic oxidative stress in an overall sense.
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PMID:Effects of quercetin on antioxidant defense in streptozotocin-induced diabetic rats. 1142 24


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