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)

A method has been developed for simultaneous analysis of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) isoenzymes in small (2.5 mg) liver biopsy cores by starch gel electrophoresis. All the currently recognized hepatic isoenzymes coded by ADH1, ADH2, ADH3 and ADH4 can be detected as can the five ALDH isoenzymes. Using this technique we have investigated the isoenzyme composition of liver samples from English and Chinese subjects and a group of chronic alcoholics. Pronounced racial differences in frequency of ADH2 and ALDH phenotypes were found--only 2 (4%) of English controls had the "atypical" ADH2 variant whereas this was present in 42 (84%) of Chinese subjects, and whereas all the English subjects had the rapidly migrating mitochondrial isoenzyme of ALDH, this was absent in 27 (54%) of Chinese. No differences in ADH or ALDH phenotype were seen in the chronic alcoholics, all of whom were of English origin, compared with the English controls, but there was a reduction in overall ALDH activity and particularly in the mitochondrial isoenzyme in those with cirrhosis. The reduction in ALDH activity is probably acquired; by limiting acetaldehyde oxidation it could be responsible for the rapid deterioration in liver function in patients who continue drinking excessively.
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PMID:Hepatic ADH and ALDH isoenzymes in different racial groups and in chronic alcoholism. 635 65

The mechanisms responsible for the increased hepatic collagen deposition in alcoholic cirrhosis remain unknown. The question of whether ethanol or acetaldehyde has a direct effect on collagen and noncollagen protein production was investigated in human fibroblasts with no detectable activity of alcohol dehydrogenase to distinguish the effects of these metabolites. To eliminate environmental factors, protein production by confluent human skin, fetal and hepatic fibroblasts was studied after three passages. Cells were labeled with [5-3H]proline for 4 hr in the presence of 0.2 mM ascorbate alone or with addition of either ethanol (50 mM) or acetaldehyde (0 to 300 microM). Rates of protein production were calculated from the radioactivities of collagenase-sensitive and collagenase-resistant proteins. Skin fibroblasts from alcoholic individual either with cirrhosis or without liver disease have comparable rates of collagen and noncollagen protein production. Acetaldehyde, in a concentration found in the liver during ethanol abuse, significantly increased collagen production by human skin fibroblasts (up to 140%), fetal fibroblasts (up to 240%) and hepatic fibroblasts (up to 70%) but the addition of ethanol had no significant effect on basal collagen production. The effect of acetaldehyde was dose-related and affected noncollagen protein production in a similar manner. Acetaldehyde did not cause changes in either proline transport or the specific activity of the proline precursor pool. This newly recognized stimulation of collagen production by acetaldehyde may be a possible mechanism of fibrogenesis in alcoholic individuals.
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PMID:Acetaldehyde stimulates collagen and noncollagen protein production by human fibroblasts. 647 53

Hepatic ethanol metabolism in the liver from carbon tetrachloride (CCl4)- treated animals was studied using non-recirculating hemoglobin-free liver perfusion system. CCl4-administration decreased ethanol uptake by the liver to 56% and 30% of the control values following the acute (24 hrs. after treatment) and chronic (8-12 weeks) treatments, respectively. In addition, 4 mM fructose, a well-known agent to increase ethanol metabolism in the liver, did not increase the hepatic uptake of ethanol in CCl4-treated livers. Hepatic alcohol dehydrogenase activity was not changed following acute and chronic CCl4 treatments. The lactate/pyruvate (cytosolic NADH/NAD) ratio as well as beta-hydroxybutyrate/acetoacetate (mitochondrial NADH/NAD) ratio significantly increased, whereas both hepatic oxygen uptake and oxidation of NADH in mitochondria remarkably decreased in parallel with the magnitude of liver injury induced by CCl4. Histological studies revealed that the liver had centrilobular coagulative necrosis with fatty droplet formations at acute phase, while bridging fibrosis between central and portal areas and the pattern of cirrhosis with conspicuous changes in the mitochondria were seen at chronic phase. These data indicate that CCl4-treatment significantly reduces hepatic ethanol metabolism via the inhibition of reoxidation of NADH, a rate limiting step of ethanol metabolism in the liver.
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PMID:Alteration of hepatic ethanol metabolism in CCL4-intoxicated rats: analysis using isolated liver perfusion system. 676 60

Vitamin A and zinc metabolism are affected both by ethanol and by hepatic cirrhosis. Ethanol causes abnormal dark adaptation by acting as a competitive inhibitor with retinol for alcohol dehydrogenase in the eye. In animals oral ethanol intake results in increased losses of zinc by the urinary and fecal routes. Vitamin A malnutrition in cirrhotics may be caused by poor diet, malabsorption, decreased hepatic vitamin A uptake, and decreased hepatic storage capacity for vitamin A. In some cirrhotic patients zinc deficiency and or protein deficiency may limit the ability to respond to vitamin A. Combined vitamin A and zinc deficiencies are common in cirrhotics and either may result in abnormal dark adaptation or impaired taste and smell. The interaction of these two micro-nutrients must be kept in mind by the clinician caring for alcoholic or alcoholic cirrhotic patients.
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PMID:Vitamin A and zinc metabolism in alcoholism. 700 92

Ethanol is easily absorbed from the intestine and diffuses quickly throughout body water. The bulk of ethanol is metabolized in the liver, where alcohol dehydrogenase, a complex mixture of isoenzymes, oxidizes ethanol to acetaldehyde. Ethanol abuse produces functional and structural changes in the gastrointestinal tract, such as in the stomach, small intestine, liver, and pancreas. Accumulating evidence suggests direct toxicity of ethanol and possibly of acetaldehyde. Fatty liver, alcoholic hepatitis, liver cirrhosis, acute and chronic gastritis, deranged structure and function of the small intestine, acute and chronic pancreatitis, and pancreatic lithiasis are some of the sequelae of ethanol abuse. Recent investigations have enhanced our understanding of the functional and structural changes of the gastrointestinal tract produced by the abuse of ethanol.
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PMID:Ethanol, the liver, and the gastrointestinal tract. 719 92

Liver alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH), the principal enzymes responsible for the oxidation of ethanol, are polymorphic at the ADH2, ADH3 and ALDH2 loci in human beings. Our previous studies have shown that, compared with nonalcoholic individuals, Chinese alcoholic patients without liver disease had significantly lower frequencies of the ADH2*2 and ADH3*1 alleles, which encode high maximum velocity beta 2- and gamma 1-ADH subunits, respectively, as well as a lower frequency of the ALDH2*2 allele, which encodes an enzymatically inactive subunit. The data strongly suggest that genetic variation in both ADH and ALDH may influence drinking behavior and the risk of alcoholism developing through acetaldehyde formation. To further investigate the possible role of acetaldehyde in the pathogenesis of alcoholic liver disease, we determined the ADH and ALDH genotype frequencies in patients with alcohol-related cirrhosis (n = 27), viral hepatitis-related cirrhosis (n = 29) and gastric and duodenal ulcer without relevance to alcohol (n = 30). We developed a new restriction fragment length polymorphism method to genotype the mutant and normal ALDH2 alleles by using polymerase chain reaction-directed mutagenesis, which proved to be simpler and faster than the conventional detection methods that use hybridization with allele-specific oligonucleotide probes. We found that the frequencies of the alleles ADH2*2 (57%), ADH3*1 (78%) and ALDH2*2 (9%) in the alcoholic cirrhotic patients were significantly lower than those in the healthy controls and in the patients with cirrhosis from viral hepatitis and with gastric and duodenal ulcer.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Polymorphism of alcohol and aldehyde dehydrogenase genes and alcoholic cirrhosis in Chinese patients. 790 79

Inherited variations in alcohol and aldehyde dehydrogenases, the principal enzymes of ethanol metabolism, have been implicated in determining susceptibility to alcoholism and alcohol-related organ damage. An association between an RFLP for the alcohol dehydrogenase-2 (ADH2) gene and alcohol-induced liver damage was demonstrated in a Caucasian population. Genotyping studies revealed an increase in the ADH3(2) allele in patients with alcohol-induced cirrhosis. PCR studies of the ALDH5 gene have demonstrated diverse polymorphism within a short segment of its coding region, with marked inter-racial variation in allele frequencies. In addition, the Caucasian alcohol-induced flushing reaction has been characterised and its relationship with phenotypic polymorphism of ALDH1 examined.
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PMID:Alcohol and acetaldehyde dehydrogenase gene polymorphism and alcoholism. 791 53

The presence of atypical liver alcohol dehydrogenase (ADH) was determined in samples of liver tissue from 222 alcoholic and nonalcoholic subjects to determine its prevalence in the Spanish population, and to evaluate the possible relationship between the presence of this isoenzyme and the development of alcoholism and alcoholic liver disease. Alcoholic patients were classified into the following groups: control subjects, with normal liver pathology (group 1), patients with noncirrhotic liver disease (group 2), and patients with cirrhosis of the liver (group 3). Nonalcoholic subjects were also divided, following the same criteria, into groups 4, 5, and 6, respectively. The prevalence of atypical ADH in the population analyzed was 16.2%. Atypical ADH was present in 14.9% of alcoholics and in 17.4% of nonalcoholics (p = NS). There were no significant differences when the prevalence of atypical ADH of alcoholic and nonalcoholic patients with similar degrees of liver pathology was compared (group 1 vs. 4, group 2 vs. 5, and group 3 vs. 6). The prevalence of atypical ADH was also similar in cirrhotic patients with respect to those of noncirrhotic liver disease and control patients, either in alcoholic or nonalcoholic groups. Our findings indicate that the prevalence of atypical ADH in the Spanish population is similar to that reported for other Caucasian groups. Moreover, the presence of atypical ADH does not play a role in the development of alcoholism nor in the development of alcoholic liver disease in the population analyzed.
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PMID:Atypical liver alcohol dehydrogenase in the Spanish population: its relation with the development of alcoholic liver disease. 821 14

Alcohol causes primary malnutrition by displacing nutrients in the diet and secondary malnutrition via malabsorption and cellular injury through direct cytotoxicity. Hepatotoxicity results from metabolic disturbances associated with the oxidation of ethanol via liver alcohol dehydrogenase (ADH) and the redox changes produced by the generated NADH (the reduced form of nicotinamide adenine dinucleotide), which in turn affects the metabolism of lipids, carbohydrates, proteins, and purines. Ethanol is also oxidized in liver microsomes by an ethanol-inducible cytochrome P450, which contributes to the alcoholic's tolerance and his increased vulnerability to the toxicity of industrial solvents, anesthetics, commonly prescribed drugs, over-the-counter analgesics, chemical carcinogens, and retinoids. Increased acetaldehyde generation, with formation of protein adducts, results in antibody production, enzyme inactivation, decreased DNA repair, impaired utilization of oxygen, glutathione depletion, free radical-mediated toxicity, lipid peroxidation, and increased collagen synthesis. Therapy may eventually improve with the use of supernutrients such as S-adenosyl-L-methionine, which replenishes glutathione, restores methylation, and attenuates liver injury, as well as dilinoleoylphosphatidylcholine, which prevents cirrhosis.
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PMID:Herman Award Lecture, 1993: a personal perspective on alcohol, nutrition, and the liver. 823 56

To determine the zonal distribution of alcohol dehydrogenase in normal and cirrhotic human livers, we measured activities of this enzyme by quantitative cytochemical analysis along the liver cell plate in liver specimens from 10 normal organ donors and from 7 children with extrahepatic biliary atresia cirrhosis. In normal human liver samples, a continuous increase in alcohol dehydrogenase activity was observed along the sinusoid from the periportal to the perivenular hepatocytes (mean extinction units from 16.2 +/- 10.0 to 58.0 +/- 14.8). A similar observation was made in cirrhotic nodules, with activity increasing continuously from nodule periphery to center (7.6 +/- 4.1 to 44.9 +/- 13.3). This study demonstrates a heterogeneous pattern of alcohol dehydrogenase distribution along the sinusoid in normal human liver specimens. In addition, demonstration of this heterogeneity in human cirrhosis suggests that the cirrhotic liver is able to maintain a parenchymal functional organization, with persistence of metabolic zonation.
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PMID:Continuous increase of alcohol dehydrogenase activity along the liver plate in normal and cirrhotic human livers. 842 16


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