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

Hepatic metabolism of ethanol to acetaldehyde by the alcohol dehydrogenase pathway is associated with the generation of reducing equivalents as NADH. Conversely, reducing equivalents are consumed when ethanol oxidation is catalyzed by the NADPH dependent microsomal ethanol oxidizing system. Since the major fraction of ethanol metabolism proceeds via alcohol dehydrogenase and since the oxidation of acetaldehyde also generates NADH, an excess of reducing equivalents is produced. This explains a variety of effects following acute ethanol administration, including hyperlactacidemia, hyperuricemia, enhanced lipogenesis and depressed lipid oxidation. To the extent that ethanol is oxidized by the alternate microsomal ethanol oxidizing system pathway, it slows the metabolism of other microsomal substrates. Following chronic ethanol consumption, adaptive microsomal changes prevail, which include enhanced ethanol and drug metabolism, and increased lipoprotein production. Severe hepatic lesions (alcoholic hepatitis and cirrhosis) develop after prolonged ethanol consumption in baboons. These injurious alterations are not prevented by nutritionally adequate diets and can therefore be ascribed to ethanol rather than to dietary inadequacy.
 ...
PMID:Differences in hepatic and metabolic changes after acute and chronic alcohol consumption. 24 Jul 42

The present paper is devoted to overview the basic concepts of ethanol-induced hepatic injury and therapeutic modalities by which alcoholic liver disease can be alleviated. The role of alcohol dehydrogenase of both hepatic and gastric origin as well as the importance of the number one metabolite acetaldehyde are discussed, furthermore the effects of microsomal ethanol oxidizing system are also described. The features of the major clinicopathological consequences of alcohol abuse fatty liver, alcoholic hepatitis are briefly outlined, and the basic pathogenetic mechanisms that lead to cirrhosis--cell necrosis, regeneration and fibroplasia--are shown. The understanding of the pathophysiology of alcohol-induced liver injury may improve the therapy with drugs and nutritional factors, and allow successful prevention through the early recognition of heavy drinkers before their social or medical disintegration. In the management of alcoholic liver diseases, among the true hepatoprotective agents a naturally occurring flavonoid silymarin and an active methyl-donor metabolite S-adenosyl-L-methionine seem to be promising. An antifibrotic treatment with colchicine might also be of importance. Further prospective, well-designed, controlled clinical trials are still warranted to evaluate real efficacy of these drugs. The hepatic consequences of alcohol abuse may be treatable, however, prevention would be the true resolution of the major global health problem of alcoholism.
 ...
PMID:Pathogenesis and management of alcoholic liver injury. 134

Two types of factors can theoretically modulate alcohol metabolism toward increased acetaldehyde production. These factors are the following: (a) individual, genetically determined isoenzymes with distinct catalytic properties, and (b) modifications of enzyme activity induced by alcohol itself or liver damage. To investigate the respective roles of these factors in white individuals, we studied the alcohol dehydrogenase phenotype, together with liver alcohol dehydrogenase and aldehyde dehydrogenase activities, in 161 patients. Patients with alcoholic cirrhosis (n = 31) were compared with three types of controls: patients with nonalcoholic cirrhosis (n = 25) and excessive (n = 62) and moderate drinkers (n = 43) without liver disease. No association between alcohol dehydrogenase-3 phenotype and alcoholic cirrhosis was found. The prevalence of atypical alcohol dehydrogenase in the four groups was less than 1%. Patients with cirrhosis, regardless of its cause, had significantly lower alcohol dehydrogenase activity than the patients without cirrhosis (p less than 0.05 and p less than 0.01 vs. excessive and moderate drinkers, respectively). Among the noncirrhotic patients, alcohol dehydrogenase activity was significantly lower in the excessive drinkers than in the moderate drinkers (p less than 0.001). Aldehyde dehydrogenase activity was not different between cirrhosis-free excessive and moderate drinkers; in contrast, compared with these two groups, it was significantly lower in the two cirrhosis groups (p less than 0.01). These results suggest that no phenotypic pattern of alcohol dehydrogenase-3 associated with alcoholic cirrhosis in white patients exists, that liver alcohol dehydrogenase activity falls as a consequence of both alcohol abuse and cirrhosis and that liver aldehyde dehydrogenase activity is unaffected by alcohol abuse and only falls after the onset of cirrhosis.
 ...
PMID:Polymorphism of alcohol dehydrogenase, alcohol and aldehyde dehydrogenase activities: implication in alcoholic cirrhosis in white patients. The French Group for Research on Alcohol and Liver. 832 17

The serum activity of alcohol dehydrogenase was determined in healthy controls and in patients with liver diseases. The mean activity in hepatoma (6.4 +/- 1.0U/L) was significantly higher (P less than 0.05) than the mean values in liver cirrhosis (2.7 +/- 0.5U/L); hepatitis (4.3 +/- 1.0U/L), obstructive jaundice (2.9 +/- 0.5U/L) and healthy controls (0.7 +/- 0.1U/L). Alcohol dehydrogenase purified by CM-cellulose chromatography from the sera of patients with hepatoma had a higher affinity for butanol long chain saturated and unsaturated alcohols than the purified enzyme from healthy controls. Similarly, hepatoma alcohol dehydrogenase oxidized ethanol very poorly (KM = 154 microM) when compared with that from healthy controls (KM = 40.2 microM). Hepatoma alcohol dehydrogenase was inhibited by pyrazole while those of other liver diseases and the healthy controls were not. These properties of serum alcohol dehydrogenase may prove useful in the early diagnosis of hepatoma since biochemical changes occur before morphological changes in the development of cancer.
 ...
PMID:Properties of serum alcohol dehydrogenase in Nigerians with primary hepatoma. 166 17

A biologic role of ethyl alcohol is analysed. The function of the liver in alcohol metabolism (90% of the total intake) in three oxidizing systems with the use of alcohol dehydrogenase, microsomal ethanol oxidizing system, and H2O2 catalase is described. Epidemiological data are given, clinical course of the alcohol-produced lesions to the liver starting from fatty degeneration, through the acute and chronic hepatitis, alcohol-produced cirrhosis up to the primary cancer of the liver are also presented in the light of authors experience.
 ...
PMID:[Alcohol and the liver]. 166 43

Little is known about factors determining individual susceptibility to the physical complications of alcohol abuse but genetically determined differences in ethanol metabolism may be important. The oxidative metabolism of alcohol is catalyzed by alcohol and aldehyde dehydrogenase. Polymorphisms have been observed at two of the five loci encoding alcohol dehydrogenase subunits: ADH2 (producing three beta subunits) and ADH3 (producing two tau subunits) and also at the locus encoding the metabolically important form of aldehyde dehydrogenase, ALDH2. We have compared ADH2, ADH3 and ALDH2 allele frequencies in patients with alcohol-related cirrhosis (n = 59) and chronic pancreatitis (n = 13) with 79 local healthy control subjects. The different alleles were detected with allele-specific oligonucleotide probes after amplification of leukocyte DNA by the polymerase chain reaction. All patients and all but one control subject were homozygous ADH2*1, encoding the beta 1 subunit. No ADH2*3 alleles were detected. All 34 patients and 39 control subjects tested were homozygous ALDH2*1 encoding the active enzyme. ADH3 allele frequencies were different in patients and control subjects. ADH3*1 frequency: control subjects, 55.1%; cirrhotic patients, 62.7%; chronic pancreatitis patients, 65.4%. The difference between the patient groups combined and the control subjects was significant (p less than 0.05; G-test of Sokal and Rohlf) if it was assumed that the allele frequency in our control population was a reasonable estimate of our local population allele frequency. These results suggest that genetically determined differences in alcohol metabolism may, in part, explain predisposition to alcohol-related end-organ damage.
 ...
PMID:Investigation of the role of polymorphisms at the alcohol and aldehyde dehydrogenase loci in genetic predisposition to alcohol-related end-organ damage. 193 84

Alcoholic hepatitis is a necrotizing, often inflammatory, process that is an important precursor to the development of cirrhosis. Acetaldehyde, which is derived from alcohol by the action of alcohol dehydrogenase, is apparently the most important factor leading to alcohol-induced liver injury. Other factors of importance in determining the appearance and rate of progression of liver diseases in patients who are chronic alcoholics include sex, nutritional status, and various immunologic reactions. In addition, there is an incompletely understood genetic predisposition to the development of alcoholic hepatitis. Several histologic features found in patients with alcoholic hepatitis have been evaluated in efforts to determine which are of prognostic value. The predominance of the alcohol-induced injury in zone III of the hepatic lobule; deposition of collagen, IgA, and fibronectin in the space of Disse; defenestration of endothelial cells; and transformation of lipocytes and myofibroblasts to fibroblasts have been investigated. Prolongation of the prothrombin time and marked elevation of serum bilirubin levels are indicators of a subgroup of patients with alcoholic hepatitis who have a poor prognosis, especially if there is also evidence of hepatic encephalopathy. Supportive care and abstinence from alcohol are the foundations of therapy. Corticosteroid therapy appears to decrease the number of early deaths in patients with severe alcoholic hepatitis. Other experimental approaches to therapy include the use of propylthiouracil, anabolic-androgenic steroids, and insulin and glucagon.
 ...
PMID:Alcoholic hepatitis: pathogenesis and approaches to treatment. 223 74

The hepatic activities and the isoenzyme patterns of both alcohol dehydrogenase and aldehyde dehydrogenase have been studied in 60 alcoholics with varying degrees of liver damage (from normal tissue or minimal changes to cirrhosis with alcoholic hepatitis) and in 24 nonalcoholics with chronic hepatitis or cirrhosis in order to ascertain their association with liver damage. In alcoholics both alcohol dehydrogenase and low-Km aldehyde dehydrogenase activities decreased proportionally with the severity of liver disease. In contrast, in nonalcoholics, there was a reduction of low-Km aldehyde dehydrogenase activity related to the severity of liver injury, but alcohol dehydrogenase was similar in patients with chronic hepatitis and nonalcoholic cirrhosis. There were no significant changes in total and high-Km aldehyde dehydrogenase activities among the different histologic groups studied, although the lowest activities were observed in patients with more severe liver injury. The prevalence of atypical alcohol dehydrogenase was similar in alcoholic (6.6%) and in nonalcoholic (8.3%) liver disease. All patients exhibited isoenzyme aldehyde dehydrogenase II, whereas isoenzyme I was not detected in 39.5% of the alcoholic patients and in 9.5% of those with nonalcoholic liver disease. The lack of aldehyde dehydrogenase I was observed in cases with the lowest enzymatic activities. These results suggest that the decrease of alcohol and aldehyde dehydrogenase activities in alcoholics is not a primary defect and, therefore, their decrease is secondary to liver damage. It is speculated that the diminution of alcohol dehydrogenase, found particularly in alcoholics, could be due to centrilobular cell necrosis.
 ...
PMID:Influence of liver disease on hepatic alcohol and aldehyde dehydrogenases. 275 31

1. Liver biopsies were performed in healthy control subjects and in subjects with alcoholic and non-alcoholic liver disease in order to examine alcohol dehydrogenase (ADH; EC 1.1.1.1) and aldehyde dehydrogenase [ALDH; aldehyde dehydrogenase (NAD+); EC 1.2.1.3] activities. Erythrocyte ALDH and ethanol metabolism were also investigated in the same subjects. 2. Fifteen per cent of the subjects studied (seven of 48 subjects tested) presented atypical ADH activity, characterized by elevated activity at pH 7.4 or 8.8 compared with that found in subjects with the usual ADH form. However, the ethanol elimination curves obtained in two subjects with atypical ADH were indistinguishable from the kinetics of the group with normal ADH. Subjects displaying atypical ADH activity showed normal liver and erythrocyte ALDH activities. 3. Considering only the subjects with the normal ADH form, hepatic ADH activity was unaltered in subjects with non-alcoholic liver disease (chronic hepatitis or cirrhosis) and in those with alcoholic steatosis. Subjects with alcoholic hepatitis or alcoholic cirrhosis showed a lower ADH activity compared with the healthy control group. 4. In spite of the changes detected in subjects with alcoholic liver disease, curves of blood ethanol concentration after oral administration of 0.4 g of ethanol/kg were indistinguishable between the alcoholic hepatitis group and the control group. 5. Hepatic ALDH activity, assayed at 300 mumol/l acetaldehyde, was found to be diminished in all liver pathologies investigated, regardless of their aetiology. Nevertheless, erythrocyte ALDH activity was not modified in subjects with non-alcoholic or alcoholic liver disease. As a result of these findings, no relationship was found between hepatic and erythrocyte ALDH.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Effect of liver disorders on ethanol elimination and alcohol and aldehyde dehydrogenase activities in liver and erythrocytes. 292 May 34

Alcohol is the most significant liver poison. Its degradation takes above all place by the alcohol dehydrogenase and the microsomal alcohol-oxidizing system. In the first step of degradation acetaldehyde develops which in enrichment evokes immediately toxic defects on the mitochondrias of the cells of the liver parenchyma and thus introduces a vicious circle. Furthermore, an increased affection of pharmacometabolites as a sequel of the alcohol-conditioned enzyme induction may lead to a defect. Alcohol influences intermediary metabolic functions: the gluconeogenesis is inhibited, multi-layer disturbances in the lipid metabolism lead to fatty degeneration of the liver. A hyperuricaemia results from overproduction in the liver as well as from decreased renal excretion. The proline formation is increased. Distinct increase of the gamma-GT-activity is an early and relatively specific indicator of the alcoholic liver defect. Morphologic and clinical manifestations are fatty degeneration of the liver, hepatitis based on fatty degeneration of the liver and cirrhosis. Apart from dose and duration of the alcohol intake additional factors require consideration. The author adopts a definite attitude to etiopathogeneis and therapeutic possibilities.
 ...
PMID:[Alcohol and the liver]. 611 57


1 2 3 4 5 6 7 Next >>