Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023890 (cirrhosis)
 42,195 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The concentration of cytochrome P-450 and activities of the microsomal enzymes aryl hydrocarbon hydroxylase and ethylmorphine demethylase were measured in hepatic tissue obtained at biopsy from 69 patients. Antipyrine half-life (AP t1/2) was measured simultaneously as an in vivo marker of drug metabolism. Values for each index of the drug-metabolizing system varied greatly, but the mean values in groups of patients with mild hepatitis or inactive cirrhosis did not differ significantly from those of controls. Hepatic cytochrome P-450 content and aryl hydrocarbon hydroxylase activity were lower in patients with severe hepatitis or active cirrhosis than in controls, but ethylmorphine demethylase activity was unchanged in the patients. Drug ingestion was associated with enhancement of drug-metabolizing enzymes in all patients but those with severe liver disease; ethylmorphine demethylase activity was enhanced proportionately more than aryl hydrocarbon hydroxylase activity or cytochrome P-450 concentration. The observation that aryl hydrocarbon hydroxylase and ethylmorphine demethylase activities are influenced to a different extent by liver disease and also by drug ingestion indicates functional heterogeneity of the hepatic microsomal drug-metabolizing system in man. Correlations between t1/2 and hepatic drug oxidases were weak, even when allowance was made for variation in liver size. Thus, the rate of drug metabolism in vivo assessed by measuring AP t1/2 does not appear to be closely related to the activity of some hepatic drug-metabolizing enzymes.
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PMID:Drug metabolism in liver disease: activity of hepatic microsomal metabolizing enzymes. 48 96

In a survey the trend of the biochemical investigations in hepatology is analysed. Together with the histologic diagnosis the function of the liver parenchyma must be determined, in which cases tolerance tests which do not only determine the function of the liver parenchyma, but also the changed functions of other organs are of importance. On the basis of own findings is shown that the ammonia metabolism in patients with hepatic encephalopathy is also disturbed in musculature. In the serum of patients with decompensated liver cirrhosis a factor could be isolated which apart from the inhibition of the utilisation of glucose has also another metabolic effect. In future we might expect an intensified search for such active metabolites. Investigations concerning the salicylaemia in patients with liver cirrhosis and experimental findings about changes of the O-demethylase activity in the fatty degeneration of the liver show the great significance of the pharmacokinetic analyses in the clinical hepatology.
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PMID:[Perspectives of clinical biochemistry in hepatology]. 85 Oct 12

Despite the epidemiological evidence of a correlation between ethanol abuse and hepatocellular carcinoma, some of the results of experimental and clinical studies remain controversial. Apart from inducing cirrhosis, which may be viewed as a precancerous liver lesion, ethanol may act as a cocarcinogen. Most investigations on this topic have focused on two aspects: ethanol's capacity to induce the cytochrome P-450-dependent microsomal biotransformation system and its interference with at least one DNA repair mechanism. Ethanol exposure enhances the capacity of mixed function oxidases to activate many chemical carcinogens, such as dimethylnitrosamine (DMN). On the other hand, ethanol exposure fails to influence DMN-induced liver carcinogenesis. The capacity of alcohol to inhibit DMN-demethylase activity has not been clearly demonstrated in experiments carried out with human tissue. In conclusion, both the effects of ethanol and their underlying mechanisms as regards liver carcinogenesis are open to debate. The link between ethanol abuse and hepatocellular carcinoma appears to be mediated mainly by its capacity to induce cirrhosis.
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PMID:Hepatocellular carcinoma, alcohol, and cirrhosis: facts and hypotheses. 165 Jun 91

To verify whether a mild, but prolonged liver injury by chemicals needing bioactivation causes both hepatic cirrhosis and the appearance of hepatocyte nodules and tumors (providing the liver has been exposed previously to initiating stimuli), diethylnitrosamine-initiated and uninitiated rats were administered thioacetamide at low dose (250 mg/l drinking water) for 6 months. Hepatocyte nodule incidence as well as changes in the drug-metabolizing system were followed at monthly intervals. In the uninitiated rats a micronodular liver cirrhosis slowly developed upon thioacetamide chronic administration; a few hepatocyte focal lesions of small size were seen from the 3rd month onward. By contrast in the diethylnitrosamine-initiated thioacetamide-treated rats the liver was macronodular because of the appearance and growth of many hepatocyte nodules; some hepatomas were also seen. During thioacetamide administration both uninitiated and diethylnitrosamine-initiated rats underwent a progressive decrease of the cytochrome P-450 liver content as well as of the activity of aminopyrine N-demethylase, ethoxycoumarin O-deethylase and ethoxyresorufin O-deethylase. On the other hand, most components of the phase II of the drug-metabolizing system were markedly enhanced. In conclusion, chronic administration of thioacetamide at low doses provided strong promoting stimuli for previously initiated hepatocytes.
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PMID:Chronic liver injury by thioacetamide and promotion of hepatic carcinogenesis. 292 Dec 70

The effect of therapy with a microsomal enzyme-inducing drug on the cirrhotic liver in male Wistar rats was investigated by morphological and biochemical means. The cirrhotic animals were treated with medroxyprogesterone acetate (MPA) 100 mg/kg body wt, i.p. daily for a week. In the cirrhotic rats liver weight was enhanced, liver protein content was increased while total liver DNA content remained unchanged upon MPA treatment. The hepatic regenerative nodule size increased, as determined by morphological means. Hepatic microsomal metabolic activity was improved, as seen by increases in NADPH-cytochrome P-450 reductase and aminopyrine N-demethylase activities and cytochrome P-450 content. Since the increases in liver protein content and metabolic activity were relatively greater in the cirrhotic than intact animals upon MPA treatment, it was suggested that the spontaneous regeneration associated with liver cirrhosis may affect the induction phenomenon. The results demonstrate that an enzyme inducer may have beneficial effects on the cirrhotic liver by elevating metabolic activity and parenchymal mass.
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PMID:Treatment of liver cirrhosis with microsomal enzyme-inducing compound in the rat. 293 1

The aim of this study was to determine the prognostic significance of functional changes in the liver during progression of cirrhosis. Liver function was quantitated weekly by the aminopyrine breath test (measuring microsomal function) and the galactose breath test (measuring cytosolic function) in rats made cirrhotic by bile duct ligation (n = 14) and in sham-surgery controls (n = 9). Nine rats died spontaneously of cirrhosis. Both the aminopyrine breath test and galactose breath test were sensitive (89%) predictors of death within 1 week, but the galactose breath test was more specific (83%). Morphometric measurements of livers from surviving cirrhotic animals and controls (n = 5 each) showed that mean hepatocyte mass was maintained in the cirrhotic livers [cirrhosis (17.0 +/- 2.0) vs. controls (13.9 +/- 0.9 gm)]. The galactose breath test was also maintained, whereas the aminopyrine breath test was significantly decreased in the surviving cirrhotics. The galactose breath test, but not the aminopyrine breath test, correlated with hepatocyte mass (r = 0.67). The aminopyrine breath test correlated with microsomal aminopyrine N-demethylase activity (r = 0.78). Serial use of quantitative liver tests allows prediction of time of death from cirrhosis in this model.
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PMID:The evolution of changes in quantitative liver function tests in a rat model of biliary cirrhosis: correlation with morphometric measurement of hepatocyte mass. 357 Jan 57

Hydroxylase and demethylase activity of cytochrome P450-dependent liver monooxygenases was estimated in healthy persons and patients with chronic diseases of the hepatobiliary system. Metabolite urine content and 4-hydroxyantipyrine and norantipyrine clearance were measured within 24 h after oral antipyrine administration (10 mg/kg). It was shown that progressive antipyrine metabolic derangements depended on the form and stage of chronic diffuse liver lesion, which was especially marked in patients with chronic active viral hepatitis, liver cirrhosis with or without ascites and with signs of encephalopathy. More considerable inhibition of N-demethylase monooxygenase activity as compared to hydroxylase activity in patients with chronic active viral hepatitis showed different sensitivity of some cytochrome P450 forms to pathogenetic factors. It could be of diagnostic value. The authors put forward the idea of interaction between the oxygenase and immune systems in drug detoxication in liver diseases.
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PMID:[Monooxigenase activity in liver diseases (study based on data of antipyrine metabolism)]. 357 85

The intact cell hypothesis states that a reduced number of intrinsically normal hepatocytes, together with hemodynamic alterations, explains decreased drug metabolism in cirrhosis. We explored this hypothesis by comparing results of the aminopyrine breath test with in vitro measurements of aminopyrine N-demethylation and morphometrically determined liver cell volume in a rat model of cirrhosis. Aminopyrine N-demethylation in vivo (ABT-k) was 0.98 +/- 0.10/h (mean +/- SD) in controls. The cirrhotic rats were separated into those with normal (NCR) and those with abnormal ABT-k (PCR). Microsomal aminopyrine N-demethylase averaged 2.08 +/- 0.77 and 2.09 +/- 0.54 mumol/min in controls and NCRs, respectively; it was reduced to 1.00 +/- 0.81 mumol/min (p less than 0.02) in PCRs. Morphometrically determined hepatocellular volume was 18.8 +/- 2.8, 17.1 +/- 1.9, and 11.6 +/- 6.1 ml in controls, NCRs, and PCRs, respectively, PCRs being lower than controls (p less than 0.01) and NCRs (p less than 0.05). When N-demethylase and cytochrome P450 were related to hepatocellular volume (in milliliters), no significant difference between the three groups was apparent. We conclude that reduced aminopyrine N-demethylation in progressed cirrhosis is mainly due to a loss of liver cell volume. The function per liver cell volume remains constant, however, thus favoring the intact cell hypothesis for the handling of slowly metabolized compounds such as aminopyrine.
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PMID:Aminopyrine N-demethylation by rats with liver cirrhosis. Evidence for the intact cell hypothesis. A morphometric-functional study. 362 18

The effect of a choline-deficient diet on microsomal cytochrome P-450 and mixed-function oxidase (MFO) activity was investigated in relation to the development of nutritional cirrhosis. In rats that received the choline-deficient diet for 28 weeks cirrhosis was evident macroscopically and histologically; control rats that received an identical diet supplemented with choline had normal livers. Microsomal cytochrome P-450 and cytochrome b5 were reduced in cirrhotic liver to 50% of control levels. Three MFO activities (ethylmorphine N-demethylase, aryl hydrocarbon hydroxylase and 7-ethoxycoumarin O-deethylase) were also reduced to 40-70% of control levels. However, the turnover number for the O-deethylation of 7-ethoxycoumarin was not reduced in cirrhotic liver. This finding suggested that certain drug oxidations may be selectively depressed in nutritional cirrhosis. To examine the possibility that selective changes in MFO activity may reflect the suppression of certain cytochrome P-450 isozymes, partially purified fractions of the cytochrome were prepared after solubilisation and hydrophobic affinity chromatography (on n-octylamino-Sepharose 4B) of cirrhotic and control liver microsomes. Analysis of these fractions by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and laser densitometry indicated that a protein band of apparent minimum molecular weight 50.5 kD was primarily affected in cirrhotic rat liver microsomes. Levels of two other bands (apparent minimum molecular weight 48 and 52.5 kD) appeared essentially unaltered. Additional electrophoretic studies, conducted under non-reduced conditions, indicated the haemoprotein nature of protein bands in the 48-55 kD region. These data strongly suggest that cirrhosis produced in rats by a choline-deficient diet is associated with selective decreases in oxidative drug metabolism and individual cytochrome P-450 isozymes.
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PMID:Drug metabolism in cirrhosis. Selective changes in cytochrome P-450 isozymes in the choline-deficient rat model. 371 30

In vitro drug metabolism studies were carried out in 97 patients with liver disease. Drug-metabolizing enzymes (aminopyrine N-demethylase and bilirubin UDP-glucuronyl transferase) were estimated in livers obtained at the time of biopsy with a Menghini needle. The patients were divided into three groups depending on clinical, biochemical, radiologic, and histologic findings: (i) mild (non-cirrhotic portal fibrosis and extrahepatic portal vein obstruction), (ii) moderate (Budd-Chiari syndrome and amebic liver abscess), (iii) severe (acute hepatitis, chronic active hepatitis, and cirrhosis). Aminopyrine N-demethylase was decreased in all liver disorders as compared to ten control liver samples. Bilirubin UDP-glucuronyl transferase was significantly lower in all liver disorders except for amebic liver abscess and extrahepatic portal vein obstruction. Both the enzymes in (i) and (ii) groups were significantly higher than in group (iii). A significant correlation was obtained between the two enzymes.
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PMID:In vitro drug metabolism in humans with different liver diseases. 664 84


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