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 mutation in the Z deficiency variant of alpha1-antitrypsin perturbs the structure of the protein to allow a unique intermolecular linkage. These loop-sheet polymers are retained within the endoplasmic reticulum of hepatocytes to form inclusions that are associated with neonatal hepatitis, juvenile cirrhosis, and hepatocellular carcinoma. The process of polymer formation has been investigated here by intrinsic tryptophan fluorescence, fluorescence polarization, circular dichroic spectra and extrinsic fluorescence with 8-anilino-1-naphthalenesulfonic acid and tetramethylrhodamine-5-iodoacetamide. These biophysical techniques have demonstrated that alpha1-antitrypsin polymerization is a two-stage process and have allowed the calculation of rates for both of these steps. The initial fast phase is unimolecular and likely to represent temperature-induced protein unfolding, while the slow phase is bimolecular and associated with loop-sheet interaction and polymer formation. The naturally occurring Z, S, and I variants and recombinant site-directed reactive loop and shutter domain mutants of alpha1-antitrypsin were used to demonstrate the close association between protein stability and rate of alpha1-antitrypsin polymerization. Taken together, these data allow us to propose a kinetic mechanism for alpha1-antitrypsin polymer formation that involves the generation of an unstable intermediate, which can form polymers or generate latent protein.
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PMID:A kinetic mechanism for the polymerization of alpha1-antitrypsin. 1009 40

The impairment of transsulphuration during methionine degradation in hepatic failure can be counteracted by treatment with S-adenosylmethionine. Regarding the pathogenesis of hepatic encephalopathy, no convincing evidence exists for tryptophan, glutamine or glutamate being involved. Portal-systemic shunting-induced hyperammonaemia may reduce plasma branched-chain amino acids. The glucose effect on urea synthesis does not exist in cirrhosis.
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PMID:Amino acid metabolism in liver disease. 1045 30

We investigated the change of tryptophan-niacin metabolism induced by carbon tetrachloride (CCl4) in rats with liver cirrhosis. The rats were injected with CCl4 (0.5 or 1 mL of 50% olive oil solution/kg body weight) twice a week for 1 or 2 mo and given phenobarbital water simultaneously. The urinary excretions of nicotinamide (Nam) and its metabolites were assayed. As the result, the urinary excretion of Nam, N1-methyl-4-pyridone-3-carboxamide (4-Py), Nam + N1-methylnicotinamide (MNA) + N1-methyl-2-pyridone-5-carboxamide (2-Py) + 4-Py was lower in the CCl4-treated groups than in the non-treated group (control) regardless of the experimental period (1 mo and 2 mo) or dosing amount of CCl4 (0.5 and 1 mL). Moreover, we investigated which pathway of tryptophan-niacin metabolism was affected in CCl4-treated rat. As the result, the possibility that the MNA-->4-Py reaction is inhibited by CCl4 treatment was suggested in this experiment.
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PMID:Tryptophan-niacin metabolism in liver cirrhosis rat caused by carbon tetrachloride. 1057 36

Neuropsychiatric symptoms due to any type of dysfunction and/or portal-systemic shunting are summarized as hepatic encephalopathy (HE). HE in the presence of liver cirrhosis and/or portal-systemic shunting has been termed portal-systemic encephalopathy (PSE). PSE is most frequent among the HE syndromes and is almost exclusively seen in patients with advanced cirrhosis and portal hypertension. Portal-systemic shunting either spontaneous due to portal hypertension, following surgical portocaval anastomosis, or subsequent to transjugular intrahepatic portosystemic stent-shunt (TIPSS) is regarded as the primary causative condition for PSE, not hepatic dysfunction per se. PSE may be considered as a disorder of multiple neurotransmitter systems among which derangements of the serotonergic system have been documented most consistently. Incipient PSE is frequently paralleled by the occurrence of sleep disorders, however, their relation to PSE remains unclear. We observed a transient increase of sleep disorders post-TIPSS, which were only in part correlated to other symptoms of PSE. Among the biochemical parameters studied only an association between arterial ammonia levels and sleep disorders became apparent, whereas no significant relation was observed for peripheral tryptophan.
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PMID:Sleep disorders and portal-systemic encephalopathy following transjugular intrahepatic portosystemic stent shunt in patients with liver cirrhosis. Relation to plasma tryptophan. 1072 Oct 53

Persistent infection with hepatitis C virus (HCV) is a major cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. All treatments known so far rely on the antiviral activity of interferon alfa (IFN-alpha) that is given alone or in combination with ribavirin. Unfortunately, only a fraction of the patients clear the virus during therapy and for those who do not respond there is currently no alternative treatment. Selectable subgenomic HCV RNAs (replicons) have been recently used to investigate the effect of IFN-alpha on HCV replication. However, it has not yet been analyzed whether other cytokines also play a role in the innate immune response against HCV. Here we show that IFN-gamma inhibits protein synthesis and RNA replication of subgenomic and genomic HCV replicons. We further show that the inhibitory action of IFN-gamma does not rely on the production of nitric oxide or the depletion of tryptophan. In conclusion, our results suggest that cytotoxic T cells and natural killer cells may contribute to HCV clearance not only by cell killing but also by producing IFN-gamma, thereby enhancing the intracellular inhibition of viral replication.
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PMID:Interferon-gamma inhibits replication of subgenomic and genomic hepatitis C virus RNAs. 1187 Mar 86

North American Indian childhood cirrhosis (CIRH1A, or NAIC), a severe autosomal recessive intrahepatic cholestasis described in Ojibway-Cree children from northwestern Quebec, is one of several familial cholestases with unknown molecular etiology. It typically presents with transient neonatal jaundice, in a child who is otherwise healthy, and progresses to biliary cirrhosis and portal hypertension. Clinical and physiological investigations have not revealed the underlying cause of the disease. Currently, liver transplantation is the only effective therapy for patients with advanced disease. We previously identified the NAIC locus by homozygosity mapping to chromosome 16q22. Here we report that an exon 15 mutation in gene FLJ14728 (alias Cirhin) causes NAIC: c.1741C-->T in GenBank cDNA sequence NM_032830, found in all NAIC chromosomes, changes the conserved arginine 565 codon to a tryptophan, altering the predicted secondary structure of the protein. Cirhin is preferentially expressed in embryonic liver, is predicted to localize to mitochondria, and contains WD repeats, which are structural motifs frequently associated with molecular scaffolds.
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PMID:A missense mutation (R565W) in cirhin (FLJ14728) in North American Indian childhood cirrhosis. 1241 87

The native serpin architecture is extremely sensitive to mutation and environmental factors. These factors induce the formation of a partially folded species that results in the production of inactive loop-sheet polymers. The deposition of these aggregates in tissue, results in diseases such as liver cirrhosis, thrombosis, angioedema and dementia. In this study, we characterize the kinetics and conformational changes of alpha(1)-antitrypsin polymerization at pH 4 using tryptophan fluorescence, circular dichroism, turbidity changes and thioflavin T binding. These biophysical techniques have demonstrated that polymerization begins with a reversible conformational change that results in partial loss of secondary structure and distortion at the top of beta-sheet A. This is followed by two bimolecular processes. First, protodimers are formed, which can be dissociated by changing the pH back to 8. Then, an irreversible conformational change occurs, resulting in the stabilization of the dimers with a concomitant increase in beta-sheet structure, allowing for subsequent polymer extension. Electron microscopy analysis of the polymers, coupled with the far-UV CD and thioflavin T properties of the pH 4 polymers suggest they do not form via the classical loop-beta-sheet A linkage. However, they more closely resemble those formed by the pathological variant M(malton). Taken together, these data describe a novel kinetic mechanism of serine proteinase inhibitor polymerization.
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PMID:Acid Denaturation of alpha1-antitrypsin: characterization of a novel mechanism of serpin polymerization. 1246 May 83

The role of the isoprenoid pathway in gastrointestinal and hepatic diseases, and its relation to hemispheric dominance, was assessed in this study. The following parameters were measured in patients with (i) acid peptic disease, (ii) ulcerative colitis, (iii) gallstones, (iv) cryptogenic cirrhosis liver, (v) Reye's syndrome, (vi) mesenteric artery occlusion, (vii) irritable bowel syndrome, and (viii) in individuals with right hemispheric, left hemispheric, and bihemispheric dominance: 1. plasma HMG CoA reductase, digoxin, dolichol, ubiquinone, and magnesium levels; 2. tryptophan/tyrosine catabolic patterns; 3. free radical metabolism; 4. glycoconjugate metabolism; and 5. membrane composition. In patients with gastrointestinal and hepatic disease there were elevated digoxin synthesis, increased dolichol, and glycoconjugate levels, and low ubiquinone and elevated free radical levels. The RBC membrane Na(+)-K+ ATPase activity and serum magnesium were decreased. There was also an increase in tryptophan catabolites and a reduction in tyrosine catabolites in the serum. There was an increase in cholesterol: phospholipid ratio and a reduction in the glycoconjugate level of RBC membrane in these groups of patients. The same biochemical patterns were obtained in individuals with right hemispheric dominance. An upregulated isoprenoid pathway and hyperdigoxinemia is characteristic of gastrointestinal and hepatic disease and in right hemispheric chemical dominance. Right hemispheric chemical dominance is important in deciding the predisposition to gastrointestinal and hepatic disease.
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PMID:Hypothalamic digoxin, cerebral chemical dominance, and regulation of gastrointestinal/hepatic function. 1269 Oct 2

Hepatic encephalopathy is a frequent complication of cirrhosis. Abnormalities of 5-hydroxytryptamine (5-HT) and its metabolites are recognized and may contribute to its pathogenesis. We therefore studied the effect of an oral tryptophan load (6-18 g) upon psychometric test scores and analyzed EEG's in alcoholic cirrhotic patients. Eight patients had had previous encephalopathic episodes related to variceal bleeds and one patient was awaiting a liver transplant. Five out of the 10 patients had at least one abnormal baseline psychometric test. Following tryptophan challenge there were no changes in blood ammonia but plasma tryptophan levels were elevated approximately 10-fold (p < 0.01 x 10(-7)). Nevertheless, there were no statistically significant changes in psychometric testing or analyzed EEG frequency distribution. All patients reported nausea or vomiting while one patient developed a short-lived serotonin like syndrome. We conclude that in this group of patients, an oral tryptophan load does not induce or worsen subclinical hepatic encephalopathy. If the high blood levels of tryptophan seen in these studies are able to influence cerebral neurotransmitter synthesis, the results do not support a primary role for abnormalities of 5-HT neurotransmission in hepatic encephalopathy.
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PMID:Oral tryptophan challenge studies in cirrhotic patients: no evidence of neuropsychiatric changes. 1456 68

Anorexia or loss of appetite, one of the most typical symptoms observed in experimental and human cirrhosis, has been proposed to be associated with altered brain serotonin (5-HT) metabolism. In order to evaluate this hypothesis, brain 5-HT, its precursor tryptophan (TRP) and its metabolite 5-hydroxyindole-acetic acid (5-HIAA) were measured in brains of rats with thioacetamide (TAA)-induced liver cirrhosis. Thioacetamide at a dose of 500 mg/l in drinking water was administered for 6 weeks and during this period food intake was carefully measured in order to monitor the loss of appetite or decrease in food intake observed in cirrhosis. Concentrations of brain TRP, 5-HT and 5-HIAA were measured by HPLC with electrochemical detection. In TAA-treated rats, concentrations of 5-HT, TRP and 5-HIAA were increased in brain (44%, 33% and 36% of controls, p < 0.01). In plasma and liver of cirrhotic rats, TRP levels were increased (195% and 43%; p < 0.01). Plasma glucose and albumin levels were decreased (50%; p < 0.01 and 31%). Food intake, growth rate and locomotor activity of TAA-treated rats also decreased (73%, 22% and 73% of controls; p < 0.01). The results of this study show that brain 5-HT concentration in rats is increased in TAA-treated rats and it may, therefore, play an important role in the pathogenesis of anorexia associated with TAA-induced cirrhosis.
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PMID:Is anorexia in thioacetamide-induced cirrhosis related to an altered brain serotonin concentration? 1504 80


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