Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P17174 (aspartate aminotransferase)
 14,872 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Acetaminophen (APAP) hepatotoxicity was investigated in rats fed ethanol and isopentanol alone or in combination in a liquid diet for 7 days. Serum levels of aspartate aminotransferase (AST) and histological examination of liver slices were used to assess hepatotoxicity. At 7 hr after intragastric administration of 0.5 or 1.0 g APAP/kg, there was no significant increase in serum levels of AST in rats treated with APAP alone, or in rats pretreated with ethanol or isopentanol alone followed by APAP. There was mild central lobular congestion in the livers of rats pretreated with ethanol alone followed by APAP. In contrast, in rats pretreated with the combination of ethanol and isopentanol, administration of APAP caused a dramatic increase in serum levels of AST, along with marked central lobular necrosis, including steatosis and ischemic changes. Hepatic glutathione levels were decreased to 40-50% of control values in APAP-treated rats that had been pretreated with ethanol either alone or in combination with isopentanol. The serum concentrations of APAP were significantly lower in rats pretreated with the combination of ethanol and isopentanol followed by 1 g APAP/kg than in rats treated with APAP alone, suggesting a greater rate of APAP metabolism. We had reported previously that combined treatment of rats with ethanol and isopentanol resulted in additive to synergistic increases in CYP3A, with no further increases in CYP2E than that caused by ethanol alone. CYP3A may, therefore, be responsible for the increased APAP hepatotoxicity caused by the combined alcohol treatment.
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PMID:Acute hepatotoxicity of acetaminophen in rats treated with ethanol plus isopentanol. 861 51

Administration of 500 mg/kg acetaminophen (APAP) to female B6C3F1 mice resulted in well-documented pathophysiological changes in the liver manifested as increased serum concentration of liver enzymes (aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and serum sorbitol dehydrogenase), centrilobular congestion, and hepatocellular degeneration and necrosis. The role of proinflammatory cytokines, including tumor necrosis factor alpha (TNF-alpha) and interleukin 1 alpha (IL-1 alpha), on the hepatotoxicity of APAP was examined at 4, 8, 12, and 24 hr following APAP administration. Neutralization of TNF-alpha or IL-1 alpha with specific antibodies partially prevented the hepatotoxic effects of APAP at the 4- and 8-hr time points. In addition, prior administration of anti-TNF-alpha antibodies shortened the recovery time following APAP treatment. While IL-1 receptor antagonist (IL-1ra) had only a modest protective effect against APAP-induced liver damage, as determined by serum enzyme release, IL-1ra had no effect on the degree of hepatic congestion or necrosis at any of the time points examined. On the other hand, administration of antibodies against IL-1ra exacerbated APAP-induced liver toxicity. These results suggest that TNF-alpha and IL-1 alpha play an important role in the degree of damage and recovery that the liver undergoes following APAP intoxication.
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PMID:Histopathology of acetaminophen-induced liver changes: role of interleukin 1 alpha and tumor necrosis factor alpha. 899 8

Effects of acute physical exercise on the acetaminophen-induced hepatotoxicity were examined in adult female rats. Rats were forced to move at a speed of 10 m/min for 2 hr in a rotating cage. Immediately following the exercise bout rats were treated with acetaminophen (APAP; 700 mg/kg, i.p.). The physical exercise enhanced the hepatotoxicity of APAP as shown by increases in alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities measured 24 hr following the treatment. A significant decrease in hepatic glutathione (GSH) was observed in the rats forced to exercise suggesting that the enhancement of APAP hepatotoxicity was associated with the depression of this endogenous tripeptide. The role of adrenergic stimulation in the exercise-induced hepatic GSH depression was examined by pretreating the animals with a receptor specific adrenergic antagonist, such as prazosin HCl (15 mg/kg, i.p.), propranolol HCl (15 mg/kg, i.p.), and yohimbine HCl (15 mg/kg, i.p.) 15 min prior to the exercise bout, but neither of the antagonists prevented the GSH depression. Administration of alpha-tocopherol acetate (450 mg/kg/day for 3 days and 150 mg/kg on day 4, i.p.) did not affect the exercise-induced GSH depression or lipid peroxidation in liver homogenates as determined by increases in malondialdehyde formation. These results suggest that neither adrenergic stimulation nor oxidative stress plays a significant role in the enhancement of APAP hepatotoxicity and hepatic GSH depression induced by acute physical exercise.
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PMID:Potentiation of acetaminophen hepatotoxicity by acute physical exercise in rats. 917 66

We report 2 fatal cases of the acetaminophen-alcohol syndrome and review 51 reported cases in the medical literature. The MEDLINE database from January 1966 to December 1995 and bibliographies of selected articles were used to obtain the case reports. Inclusion criteria were a clear history of alcohol use, a history of acetaminophen use and/or an elevated serum acetaminophen level, peak aspartate aminotransferase (AST) greater than 800 U/L, and exclusion of other causes of hepatotoxicity by negative hepatitis serologies and/or a liver biopsy showing typical findings of acetaminophen toxicity. Demographic characteristics, clinical features, treatment, and outcome were extracted from reports meeting inclusion criteria and our own 2 cases. This syndrome affected relatively young, frequently healthy patients. Acetaminophen was invariably taken for nonsuicidal intent. The mortality rate was 32%. A typical laboratory picture was defined, characterized by an extraordinarily high AST level. Treatment with N-acetylcysteine was not effective due to delayed presentation and diagnosis. Patients who use alcohol and health care providers should be educated about this potentially fatal syndrome. Prevention is the key to reducing its occurrence.
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PMID:Enhanced hepatotoxicity of acetaminophen in the alcoholic patient. Two case reports and a review of the literature. 919 53

The hepatoprotective effect of various fractions (n-hexane, CHCl3, EtOAc, n-BuOH, and H2O) of Ban-zhi-lian derived from Scutellaria rivularis Benth was studied against carbon tetrachloride (CCl4), D-galactosamine (D-GalN) and acetaminophen (APAP)-induced acute hepatotoxicity in rats. Liver damage was assessed by quantifying serum activities of glutamate oxaloacetate transaminase (sGOT) and glutamate pyruvate transaminase (sGPT), as well as by histopathological examination. The results indicated that the CHCl3 fraction and EtOAc fractions exhibited the greatest hepatoprotective effects on CCl4-induced liver injuries, the CHCl3 fraction and n-hexane fraction are most potent against D-GalN-induced intoxication, and the CHCl3 fraction represented the most liver-protective effect on APAP-induced hepatotoxicity. The pathological changes of hepatic lesions caused by these three hepatotoxicants were improved by treatment with the fractions mentioned above, which were compared to Glycyrrhizin (GLZ) and Silymarin as standard reference medicines.
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PMID:Hepatoprotective effect of the fractions of Ban-zhi-lian on experimental liver injuries in rats. 920 8

Recent evidence suggests that macrophages and/or other nonparenchymal cells may release important mediators contributing to the hepatic necrosis induced by high doses of acetaminophen (APAP). The nature and causative role of these mediators has remained elusive, however. To investigate the role of the proinflammatory cytokine, tumor necrosis factor (TNF) in the initiation and early propagation of APAP-induced liver injury, we have used mice deficient in both TNF and the closely related lymphotoxin-alpha (LT-alpha). Male TNF/LT-alpha knockout mice and C57BL/6 wild-type mice were treated with a hepatotoxic dose of APAP (400 mg/kg, intraperitoneally), and the development of liver injury was monitored over 8 hours. Both genotypes exhibited similar basal activities of hepatic cytochrome P450 2E1 and 1A2. After APAP administration, both the rate of glutathione consumption and the extent of subsequent selective protein binding did not differ significantly in the knockout and wild-type mice. The TNF/LT-alpha-deficient mice developed severe centrilobular necrosis and exhibited highly increased levels of serum alanine aminotransferase and aspartate aminotransferase, the extent of which was not significantly different from that in wild-type mice. In C57BL/6 mice exposed to APAP, no increases in hepatic transcripts of TNF or LT-alpha were found by reverse transcription-polymerase chain reaction, nor was immunoreactive serum TNF detected by enzyme-linked immunosorbent assay over 8 hours posttreatment. These data indicate that, in the absence of the genes encoding for TNF and LT-alpha, APAP bioactivation was not altered and mice still developed severe hepatic necrosis. Thus, TNF is unlikely to be a key mediator in the early pathogenesis of APAP-induced hepatotoxicity.
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PMID:Acetaminophen hepatotoxicity in tumor necrosis factor/lymphotoxin-alpha gene knockout mice. 953 42

The potential of protopine to inhibit microsomal drug metabolising enzymes (MDM E) and prevent paracetamol- and CCl4-induced hepatotoxicity was studied in rats. Paracetamol at the dose of 640 mg kg-1 produced hepatic damage in rats as manifested by the rise in serum levels of aspartate transaminase (AST) and alanine transaminase (ALT) to 972+/-186 and 624+/-131 IU (mean+/-sem; n=10), respectively, compared to respective control values of 101+/-29 and 64+/-18 IU. Pretreatment of rats with protopine (11 mg kg-1, orally twice daily for 2 days) lowered significantly the respective serum AST and ALT levels (P<0.05) to 289+/-52 and 178+/-43 IU. The hepatotoxic dose of CCl4 (1.5 ml kg-1; orally) raised serum AST and ALT levels to 543+/-89 and 387+/-69 IU (mean+/-sem; n=10), respectively, compared to respective control values of 98+/-28 and 56+/-17 IU. The same dose of protopine (11 mg kg-1) was able to prevent significantly (P<0.05), the CCl4-induced rise in serum enzymes and the estimated values of AST and ALT were 168+/-36 and 93+/-28 IU, respectively. Protopine caused prolongation (P<0.05) in pentobarbital (55 mg kg-1)-induced sleep as well as potentiated strychnine-induced toxicity in rats, suggestive of an inhibitory effect on MDME. These results indicate that protopine exhibits anti-hepatotoxic action which may be mediated through inhibition of MDME.
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PMID:An assessment of the potential of protopine to inhibit microsomal drug metabolising enzymes and prevent chemical-induced hepatotoxicity in rodents. 978 72

The aim of the paper is to present a case of self-poisoning with paracetamol, overdosed just before a delivery. A 21-year-old woman was admitted to Obstetric and Gynecology Ward of local hospital in the second stage of physiological delivery, more than 6 hours after she had ingested 19 g of acetaminophen for self-poisoning. She delivered a normal infant weighing 3520 g who had Apgar scores of 10, and then both infant and mother were sent in an emergency ambulance to the nearest poison centre. Blood samples for toxicological examination were taken on admission to toxicological intensive care unit i.e. 11 hours post maternal ingestion. Acetaminophen levels of both patients were above the acetaminophen overdose nomogram line and the antidote treatment, i.v. N-acetylcysteine was administered according to the protocol: the mother within 11 hours post-ingestion and approximately 4 hours after a delivery; the neonate within 11 hours post maternal ingestion and 4 hours of life. Higher paracetamol concentration in the blood of infant compared to the mother's was noted in the first and then control toxicological examination performed within 35 hours post maternal ingestion. Peak maternal aspartate aminotransferase (AST) activity was 326 U/L within 35 hours and alanine aminotransferase (ALT) activity was 262 U/L within 56 hours post-ingestion. The highest neonatal enzyme activity was noted within 11 hours post maternal ingestion of paracetamol, and the elevation was not high. Except moderate anaemia in the mother, no clinical or biochemical symptoms of renal, cardiovascular or CNS injury were stated in the mother or infant. Normalisation in the maternal enzymes activity was stated within 226 hours, while in the neonatal within 58 hours post maternal ingestion. The woman recovered without sequelae and was discharged from hospital on the 11th day following paracetamol overdosing. No evidence of the liver injury was found in the infant either.
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PMID:Suicidal paracetamol poisoning of a pregnant woman just before a delivery. 1046 99

Paracetamol-induced hepatic necrosis is the most common form of toxic liver injury experienced in clinical practice in the UK and USA. Recently, reports have described prevention of hepatic necrosis, induced by other hepato-toxins, by inhibiting tumour necrosis factor alpha (TNFalpha). The aim of the present study was to determine the role of TNFalpha in paracetamol-induced hepatic necrosis. Six-week-old CBA/J female mice were given 300 mg/kg paracetamol by intraperitoneal (IP) injection after an 8-h fast. Hepatic expression of TNFalpha was measured by enzyme-linked immunoassay (ELISA) and reverse transcriptase-polymerase chain reaction (RT-PCR). Serum TNFalpha was measured by ELISA. One hour prior to paracetamol injection, mice were also given blocking anti-TNFalpha antibodies, soluble TNFalpha receptor, interleukin 10 (IL-10), and dexamethasone. Hepatic injury was measured by serum aspartate aminotransferase and histological assessment on haematoxylin and eosin (H&E)-stained liver sections. There was a significant increase in serum TNFalpha at 6 h (control 0.002+/-0.002 ng/ml, n=7; paracetamol-treated 0.022+/-0.007 ng/ml, n=5, p<0.05), but hepatic TNFalpha expression did not change up to 24 h following paracetamol injection. Histologically severe centrilobular hepatic necrosis was noted at 3 h and progressed for 24 h after paracetamol poisoning. Death rate, serum aspartate aminotransferase, and hepatic histology were not significantly different between the groups treated with blocking anti-TNFalpha antibodies, soluble TNFalpha receptor, IL-10, and dexamethasone, compared with controls. In conclusion, there is no evidence to suggest that modulation of TNFalpha expression affects hepatic injury following experimental paracetamol poisoning; anti-TNFalpha therapies are therefore unlikely to be effective in the corresponding clinical situation.
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PMID:Inhibition of tumour necrosis factor alpha does not prevent experimental paracetamol-induced hepatic necrosis. 1070

The effect of aqueous leaf extract of Azadirachta indica (A. indica) was evaluated in paracetamol induced hepatotoxicity in rats. Liver necrosis was produced by administering single dose of paracetamol (2 g/kg, p.o.). The liver damage was evidenced by elevated levels of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma glutamyl transpeptidase (gamma-GT) and by histopathological observations of liver sections. Aqueous A. indica leaf extract (500 mg/kg, p.o.) significantly (P < 0.01) reduced these elevated levels of AST, ALT and gamma-GT. Paracetamol induced liver necrosis was also found to be reduced as observed macroscopically and histologically.
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PMID:Effect of Azadirachta indica (Neem) leaf aqueous extract on paracetamol-induced liver damage in rats. 1091 97


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