Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.6.1.1 (aspartate aminotransferase)
 21,665 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Acacia confusa Merr. (Leguminosae), a species native to Taiwan, is widely distributed on the hills and lowlands of Taiwan, and has been traditionally used as a medicine. The hepatoprotective effects of A. confusa bark extract (ACBE) and its active constituent gallic acid were evaluated against carbon tetrachloride (CCl(4))-induced hepatotoxicity in rats. CCl(4)-induced hepatic pathological damage and significantly increased the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and malondialdehyde (MDA) in plasma, and cytochrome P4502E1 (CYP2E1) protein expression in hepatic samples, and decreased the activities of superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT) in erythrocytes. Treatment with ACBE, gallic acid or silymarin could decrease significantly the AST, ALT, and MDA levels in plasma, and CYP2E1 expression in liver tissues, and increase the activities of SOD and GPX in erythrocyte when compared with CCl(4)-treated group. Liver histopathology also showed that ACBE, gallic acid or silymarin could significantly reduce the incidence of liver lesions induced by CCl(4). These results suggested that the ACBE and gallic acid exhibit potent hepatoprotection against CCl(4)-induced liver damages in rats, and the hepatoprotective effects of ACBE and gallic acid may be due to the modulation of antioxidant enzymes activities and inhibition of lipid peroxidation and CYP2E1 activation.
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PMID:Protective effect of Acacia confusa bark extract and its active compound gallic acid against carbon tetrachloride-induced chronic liver injury in rats. 1932 82

It is established that rabbits kept under the conditions of 30-day hypodynamia with high-grade feeding exhibit disorders in both structure and functions of the liver, which are classified as nonalcoholic type fatness. Other disturbances are an increase in the activity of aspartate aminotransferase (AsAT) and alanine aminotransferase (AlAT) and a decrease in the total protein content predominantly at the expense of albumin. The development of a syndrome of mesenchymal inflammation is manifested by a relative growth of the alpha1, alpha2 and gamma-protein fractions. Pronounced violations of the lipid metabolism were manifested by a growth in the content of beta-lipoproteins, triglycerides, general cholesterol, and low-density lipoproteins and by a decrease in the level of high-density lipoproteins in the blood serum of animals. An increase in the content of malonic dialdehyde was accompanied by a drop in the activity of catalases in the blood serum and erythrocytes of rabbits. Investigation of the morphology of liver tissues showed evidence for small- and large-drop diffuse steatosis, which was most expressed in the central zones of lobes. Using of cytochrome C and mexidol, it is possible to reduce the expression of disorders to various degrees and, in some cases, to prevent the development of pathological changes.
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PMID:[The influence of mexidol on the liver functions, structure, and parameters of lipid peroxidation under long-term hypodynamia conditions]. 1944 31

Lung cancer remains a leading cause of disease globally, with smoking being the largest single cause. Phase I enzymes, including cytochrome P(450), family 1, subfamily A, polypeptide 1 (CYP1A1), are involved in the activation of carcinogens, such as polycyclic aromatic hydrocarbons, to reactive intermediates that are capable of binding covalently to DNA to form DNA adducts, potentially initiating the carcinogenic process. The aim of the present study was to investigate the association of CYP1A1 gene polymorphisms and haplotypes with lung cancer risk. A case-control study was carried out on 1,040 nonsmall cell lung cancer (NSCLC) cases and 784 controls to investigate three CYP1A1 variants, CYP1A1*2A (rs4646903; thymidine to cytosine substitution at nucleotide 3801 (3801T>C)), CYP1A1*2C (rs1048943; 2455A>G; substitution of isoleucine 462 with valine (exon 7)) and CYP1A1*4 (rs1799814; 2453C>A; substitution of threonine 461 with asparagine (exon 7)) using PCR restriction fragment length polymorphism methods. The CYP1A1*2A and CYP1A1*2C variants were significantly over-represented in NSCLC cases compared with controls, whereas the CYP1A1*4 variant was under-represented. CYP1A1 haplotypes (in allele order CYP1A1*4, CYP1A1*2C, CYP1A1*2A) CGC and CGT were associated with an increased risk of lung cancer, whereas AAT was associated with decreased lung cancer risk in this population. The present study has identified risk haplotypes for CYP1A1 in NSCLC and confirmed that CYP1A1 polymorphisms are a minor risk factor for NSCLC.
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PMID:Genetic association study of CYP1A1 polymorphisms identifies risk haplotypes in nonsmall cell lung cancer. 1960 85

A case of colchicine-induced rhabdomyolysis is reported. A 48 year old African-American male with history of hypertension and chronic gout on colchicine 0.6 mg daily presented with symptoms of a community acquired pneumonia. The patient was started on 500 mg of clarithromycin orally twice daily and represented to the emergency room after 3 days complaining of severe muscle pain. His liver panel showed elevations in the serum aminotransferases; AST 513 mU/ml (nl 15-41) and ALT 182 mU/ml (nl 17-63). His complete blood count showed an elevated white blood cell count of 18,800/ml (nl 4,000-10,000/ml). Urine analysis was positive for myoglobin with no red cells present. Serum creatine kinase (CK) was 22,996 mU/ml (nl 31-221) with a normal troponin I 0.18 (nl <0.4).Investigations confirmed the presence of rhabdomyolysis and discontinuation of colchicine and clarithromycin resulted in resolution of clinical and biochemical features of rhabdomyolysis. By hospital day four, his muscle soreness had improved markedly. His serum CK improved to 3,389 mU/ml (nl 31-221 mU/ml) and serum creatinine improved to 1.5 mg/dl (nl 0.8-1.2). On hospital day five, the patient was discharged on oral anti-hypertensive medication and a ten-day course of doxycycline. Metabolism of colchicine by the cytochrome P450 3A4 system has been previously described, but this is the first published report of colchicine associated rhabdomyolysis secondary to drug metabolism interactions with an antibiotic. A review of medications that are metabolized via the cytochrome 3A4 and A-SLAVED-LIVER (Amiodarone, Simvastatin, Lovastatin, Atorvastatin, Verapamil, Erythromycin, Diltiazem, cLarithromycin, Itraconazole, Voriconazole, colchicinE, Ritonavir) pneumonic was established.
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PMID:Short term treatment with clarithromycin resulting in colchicine-induced rhabdomyolysis. 2541 92

Although it is becoming increasingly common to accept livers from older donors for transplantation, old livers are more damaged by hepatic ischemia and reperfusion injury (HIRI) than young livers. We hypothesized that this age-related susceptibility to HIRI is due to increased hepatocellular apoptosis driven by tumor necrosis factor alpha (TNFalpha). Young (6-week-old) and old (60-week-old) mice underwent 60 minutes of hepatic ischemia and increasing periods of reperfusion. TNFalpha was determined by enzyme-linked immunosorbent assay. Liver injury (enzyme release), apoptosis (terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-digoxigenin nick-end labeling staining, cytochrome C release, and caspase activation), and necrosis (hematoxylin and eosin staining) were assessed. We assessed the impact of apoptosis by blocking TNFalpha production or effect (pentoxifylline and TNFalpha receptor knockout), inhibiting apoptotic pathways (caspase inhibition), or imposing a hepatic protective strategy [glucose infusion with ischemic preconditioning (Glc/PC)]. In comparison with young livers, old livers subjected to HIRI had more pronounced liver aspartate aminotransferase release (6200 versus 3900 U/L, P = 0.02), necrosis (45% versus 25%, P = 0.03), and apoptosis with increased 30-minute TNFalpha release (19.02 versus 10.62 pg/mg, P = 0.03). Eliminating TNFalpha production reversed the effect of age, as did inhibition of apoptotic pathways with caspase inhibition. Glc/PC of old mice attenuated TNFalpha release (9.56 versus 19.02 pg/mg, P = 0.001) and age-related exaggerated HIRI and improved survival (60% versus 0%). In conclusion, the age-related susceptibility to HIRI is driven by an exaggerated induction of TNFalpha-dependent hepatocellular apoptosis. Targeting the apoptotic cascade has implications for the older donor liver population.
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PMID:Exaggerated up-regulation of tumor necrosis factor alpha-dependent apoptosis in the older mouse liver following reperfusion injury: targeting liver protective strategies to patient age. 1987 8

We evaluated whether repeated arsenic preexposure can increase acetaminophen-induced hepatic oxidative stress. Rats were exposed to arsenic (25 ppm; rat equivalent concentration of maximum groundwater contamination level) via drinking water for 28 days. Next day, they were given single oral administration of acetaminophen (420 or 1000 mg/kg b.w.). Hepatotoxicity was evaluated by assessing serum biomarkers, cytochrome-P450 (CYP) content, CYP3A4- and CYP2E1-dependent enzymes, lipid peroxidation and antioxidants. Arsenic or acetaminophen increased serum ALT and AST activities and depleted CYP. Arsenic decreased, but acetaminophen increased CYP-dependent enzyme activities. These agents independently increased lipid peroxidation and decreased antioxidants. Arsenic did not alter the effects of acetaminophen on serum biomarkers, caused further CYP depletion and decreased acetaminophen-mediated induction of drug-metabolizing enzymes. Arsenic enhanced the lower dose of acetaminophen-mediated lipid peroxidation and glutathione depletion with no further alterations in enzymatic antioxidants. However, arsenic attenuated the higher dose-mediated lipid peroxidation and glutathione depletion with improvement in glutathione peroxidase and glutathione reductase activities, further decrease in catalase and no alterations in superoxide dismutase and glutathione-S-transferase activities. Results show that arsenic preexposure increased the susceptibility of rats to hepatic oxidative stress induced by the lower dose of acetaminophen, but reduced the oxidative stress induced by the higher dose.
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PMID:Influence of repeated preexposure to arsenic on acetaminophen-induced oxidative stress in liver of male rats. 1993 28

The present study investigated the preventive effect of eugenol, a naturally occurring food flavouring agent on thioacetamide (TA)-induced hepatic injury in rats. Adult male Wistar rats of body weight 150-180 g were used for the study. Eugenol (10.7 mg/kg b.w./day) was administered to rats by oral intubation for 15 days. TA was administered (300 mg/kg b.w., i.p.) for the last 2 days at 24h interval and the rats were sacrificed on the 16th day. Markers of liver injury (aspartate transaminase, alanine transaminase, alkaline phosphatase, gamma-glutamyl transferase and bilirubin), inflammation (myeloperoxidase, tumor necrosis factor-alpha and interleukin-6), oxidative stress (lipid peroxidation indices, protein carbonyl and antioxidant status) and cytochrome P4502E1 activity were assessed. Expression of cyclooxygenase-2 (COX-2) and the extent of DNA damage were analyzed using immunoblotting and comet assay, respectively. Liver injury and collagen accumulation were assessed using histological studies by hematoxylin and eosin and Masson trichrome staining. Rats exposed to TA alone showed increased activities of hepatocellular enzymes in plasma, lipid peroxidation indices, inflammatory markers and pro-inflammatory cytokines and decreased antioxidant status in circulation and liver. Hepatic injury and necrosis were also evidenced by histology. Eugenol pretreatment prevented liver injury by decreasing CYP2E1 activity, lipid peroxidation indices, protein oxidation and inflammatory markers and by improving the antioxidant status. Single-cell gel electrophoresis revealed that eugenol pretreatment prevented DNA strand break induced by TA. Increased expression of COX-2 gene induced by TA was also abolished by eugenol. These findings suggest that eugenol curtails the toxic effects of TA in liver.
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PMID:Investigation of antioxidant, anti-inflammatory and DNA-protective properties of eugenol in thioacetamide-induced liver injury in rats. 2003 7

The localization of the key photoreductive and oxidative processes and some stress-protective reactions within leaves of mesophytic C(3) plants were investigated. The role of light in determining the profile of Rubisco, glutamate oxaloacetate transaminase, catalase, fumarase, and cytochrome-c-oxidase across spinach leaves was examined by exposing leaves to illumination on either the adaxial or abaxial leaf surfaces. Oxygen evolution in fresh paradermal leaf sections and CO(2) gas exchange in whole leaves under adaxial or abaxial illumination was also examined. The results showed that the palisade mesophyll is responsible for the midday depression of photosynthesis in spinach leaves. The photosynthetic apparatus was more sensitive to the light environment than the respiratory apparatus. Additionally, examination of the paradermal leaf sections by optical microscopy allowed us to describe two new types of parenchyma in spinach-pirum mesophyll and pillow spongy mesophyll. A hypothesis that oxaloacetate may protect the upper leaf tissue from the destructive influence of active oxygen is presented. The application of mathematical modeling shows that the pattern of enzymatic distribution across leaves abides by the principle of maximal ecological utility. Light regulation of carbon metabolism across leaves is discussed.
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PMID:Untangling metabolic and spatial interactions of stress tolerance in plants. 1. Patterns of carbon metabolism within leaves. 2044 59

The double null mutation of glutathione transferase, GSTM1 and GSTT1, is reported to influence troglitazone-associated abnormal increases of alanine aminotransferase and aspartate aminotransferase. However, no nonclinical data with a bearing on the clinical outcomes and underlying mechanisms have hitherto been reported. To investigate whether deficiency in GSTM1 and/or GSTT1 is related to troglitazone hepatotoxicity in vitro, the covalent binding level (CBL) (an index of reactive metabolite formation) and cytotoxicity of troglitazone and rosiglitazone, another thiazolidinedione but with low hepatotoxicity, were examined using human liver samples phenotyped for cytochrome P450s and genotyped for GSTM1 and GSTT1. Despite addition of GSH, CBLs of troglitazone and rosiglitazone in human liver microsomes were correlated with CYP3A (or CYP2C8) and CYP2C8 activities, respectively. With addition of recombinant GSTM1, the microsomal CBLs of troglitazone and rosiglitazone decreased. However, the CBLs of troglitazone in GSTM1/GSTT1 wild-type hepatocytes were unexpectedly higher than those in null hepatocytes. Although this discrepancy has not been fully explained, the GSTM1 and GSTT1 null mutations increased the cytotoxicity of troglitazone, independent of CYP3A or CYP2C8 activities. Furthermore, a GSH adduct of troglitazone, M2, limited to GSTM1 wild-type hepatocytes was detected. Of clear interest, GSTM1 and/or GSTT1 null mutation-dependent cytotoxicity and higher exposure to the reactive metabolite trapped as M2 as for troglitazone were not observed for rosiglitazone. This result might at least partly explain the findings related to clinical hepatotoxicity, suggesting that measurement of GSH adducts or cytotoxicity using GSTM1- and GSTT1-genotyped hepatocytes might offer an important in vitro system to assist in better prediction of idiosyncratic hepatotoxicity.
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PMID:In vitro investigation of the glutathione transferase M1 and T1 null genotypes as risk factors for troglitazone-induced liver injury. 2151 44

It is well known that schistosomal infection and food contamination with aflatoxins caused marked histopathological changes in human liver. This study demonstrates the influence of Schistosoma mansoni infection on the capacity of drug-metabolizing enzymes and in vitro aflatoxin B-1 metabolism in human liver. Clinical data showed an increase in alkaline phosphatase, alanine and aspartate aminotransferase by 82, 74 and 100%, respectively. The activity of NADPH cytochrome C reductase and cytochrome P-450 content were significantly decreased in the liver of schistosomal patients by 70 and 52% respectively. The cytochrome b-5 content was also decreased by 61%. Aflatoxin B-1 tris-diol could not be detected using the microsomal fractions of the schistosomal group relative to the control group. The content of aflatoxin Q(1) metabolite produced by microsomal fractions of schistosomal patients increased by 308%. There was no difference in the formation of aflatoxin M(1) between the two groups. These observations indicate that Schistosoma mansoni infection might potentiate the deleterious effects of environmental carcinogens.
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PMID:Influence of Schistosoma mansoni infection on carcinogen-metabolizing capacities and in vitro aflatoxin B-1 metabolism in human liver. 2159 52


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