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)

This contribution presents data from the literature as well as our own results concerning the mechanisms of hepatic encephalopathy (HE). 1. Blood chemistry: In patients with liver cirrhosis, the plasma levels of ammonia, phenylalanine, tyrosine, phenolic acids, and octopamine correlated with the stages of HE. Methionine and free tryptophan concentrations were increased only in stages 2-4. Further, branched chain amino acids were below the normal range. Experimental findings in animals elucidated some mechanisms of these changes. 2. Effects of administered substances: With ammonia, methionine, methanethiol, tryptophan, phenolic substances, and fatty acids central nervous disturbances were observed. 3. Interactions: Anemia, methanethiol, and fatty acids favored ammonia toxicity. Alkalosis diminished cerebral symptoms. 4. Neurotransmitters: HE was accompanied by an enhanced turnover of serotonin and by increased amounts of false neurotransmitters (like octopamine) in the brain. 5. Oxydative brain metabolism: Disorders of cerebral oxygen and glucose utilization were mainly documented in cases of long term HE with EEG alterations. 6. Structural changes of the brain: Most of them are irreversible.
 ...
PMID:[Pathogenesis of hepatic encephalopathy (author's transl)]. 1 66

When amino acid solutions with high concentrations of branched chained amino acids and low concentrations of aromatic amino acids were administered to patients with cirrhosis of the liver 1. the serum levels of tyrosine and phenylalanine were significantly reduced, 2. the molar ratio of the branched chained amino acids to the aromatic amino acids substantially increased, and 3. as therapeutic response in all cases treated, a marked improvement of hepatic encephalopathy was achieved.
 ...
PMID:[Therapy of hepatic encephalopathy. Modification of the plasma aminogram using amino acid infusions]. 11 May 63

A mixture with essential and nonessential amino acids high in branched chain amino acids and low in aromatic amino acids (Fischer solution), and another synthetic mixture of branched chain amino acids containing 3 amino acids associated with the urea cycle (Hep-OU) were infused to control subjects and patients with severe hepatic disease. Alterations in serum aminograms, blood ammonia levels and electroencephalograms following the infusion were studied and compared with those obtained by a commercially available amino acid mixture. Short-term or continuous infusion of a commercially available amino acid solution to cirrhotic patients caused an increase in methionine, phenylalanine and tyrosine and a decrease in branched chain amino acids. These post-infusion results were similar to the patterns seen in hepatic encephalopathy. In cirrhotic patients, infusion of Fischer solution which contains small quantities of methionine and phenylalanine produced an increase in the concentrations of these 2 amino acids, probably because of impaired utilization by the injured liver. No marked alterations in serum aminograms, however, were observed in cirrhotic patients either immediately after, or 3 h after, the end of the Hep-OU infusion. Reduction of methionine, tyrosine and phenylalanine levels and elevation of the molar ratio of (valine + leucine + isoleucine)/(phenylalanine + tyrosine) were significant. The infusion of Hep-OU to patients with liver cirrhosis or subacute hepatitis resulted in clinical and neurological improvements and the restoration of the molar ratio of branched chain amino acids/aromatic amino acids.
 ...
PMID:An approach to nutritional therapy of hepatic encephalopathy by normalization of deranged amino acid patterns in serum. 15 28

Encephalopathic patients with cirrhosis of the liver consistently showed elevated levels of the aromatic amino acids, phenylalanine, tyrosine and free tryptophan as well as methionine in serum, whereas levels of the branched chain amino acids, valine, leucine and isoleucine, were depressed. Comatose patients with fulminant hepatitis had markedly elevated levels of all amino acids, the results being greatly different from those of cirrhotic patients. Molar ratios of (valine + leucine + isoleucine)/(phenylalanine + tyrosine) decreased both in cirrhotics with and without encephalopathy and in cases with fulminant hepatitis. Infusion of a commercially available L-amino acid solution in a cirrhotic patient induced a strikingly abnormal aminogram documented in hepatic encephalopathy. Therefore, effects of branched chain amino acid infusion on the deranged amino acid pattern were primarily studied for the purpose of improvement in hepatic encephalopathy by normalization of serum amino acid patterns. Elevated levels of the aromatic amino acids and methionine could be apparently depressed in a cirrhotic patient by this type of infusion but not in a case of fulminant hepatitis probably because of the poor utilization of these amino acids in severely impaired liver.
 ...
PMID:Serum amino acids in hepatic encephalopathy--effects of branched chain amino acid infusion on serum aminogram. 52 13

The effect of varying dietary protein content on the daily rhythms in plasma neutral amino acid concentrations was studied in patients with chronic cirrhosis. For two consecutive 5-day periods, subjects consumed diets containing either 0 or 75 g of protein per day. Blood samples were drawn at 4-hr intervals on the 4th and 5th days of each dietary period. For most of the neutral amino acids, the changes in plasma concentration associated with time of day or with variations in dietary protein content were similar to those observed previously in normal subjects. Ingestion of the protein-free diet caused significant reductions in the daytime level of all amino acids studied, except for tryptophan, the concentration of which did not change during the 24-hr period. Ingestion of the 75-g protein diet caused plasma levels of most of theamino acids to increase slightly during the day; these increments were not statistically significant for tryptophan, tyrosine, leucine, and methionine. The absolute plasma concentrations of most of the neutral amino acids were also in the normal range; exceptions included methonine, tyrosine, and phenylalanine, whose plasma levels were significantly elevated above normal valves. The plasma ratios of tryptophan, tyrosine, and phenylalanine concentrations to the sum of the concentrations of other large neutral amino acids increased during the day uhen the protein-free diet was ingested; this effect was moderated by the addition of protein to the food. The plasma ratios for the branched-chain amino acids were depressed below normal; those for tyrosine, phenylalanine, and methionine were significantly increased. The plasma tryptophan ratio was within the normal range. These findings provide a basis for anticipating that the uptake from blood into brain of several of the large neutral amino acids may be modified in patients with chronic cirrhosis.
 ...
PMID:Diurnal variations in plasma neutral amino acid concentrations among patients with cirrhosis: effect of dietary protein. 57 62

The effect on free plasma amino acids before and after infusion of 1 mg glucagon was studied at rest after an overnight fast in seven patients with compensated liver cirrhosis and in seven healthy controls. Total aminoacidaemia in cirrhotic patients is significantly higher than in controls. Elevated basal levels in cirrhotics are found particularly in tyrosine, citrulline, tryptophane, threonine, phenylalanine, and methionine whereas ornithine and serine levels are decreased. Save for the redox couple cystine-cysteine which increases, glucagon elicits an decrease in most amino acids that is proportionate to their initial level. Total aminoacidaemia decreases in controls and cirrhotics by 14.6 and 9.1 per cent respectively. Serum ammonia level rises significantly in both groups, urea increases only in controls, uricaemia remains virtually unchanged.
 ...
PMID:The effect of glucagon on free plasma amino acids in cirrhotics and healthy controls. 63 37

The molar ratio valine + leucine + isoleucine/phenylalanine + tyrosine was determined in the plasma of patients with liver disease of varying aetiology and severity and in an age and sex matched control group. In the control group of 58 subjects the mean ratio was 3.3 +/- 0.5 (ISD). The mean ratio was significantly lowered in groups of 25 patients with alcoholic cirrhosis (P less than 0.001), 25 patients with chronic active hepatitis (P less than 0.001), 23 patients with primary biliary cirrhosis (P less than 0.001), and 11 patients with cryptogenic cirrhosis (P less than 0.001). In a group of 50 patients with cirrhosis, the ratio was significantly lowered (P less than 0.001) irrespective of the presence of hepatic encephalopathy. A good correlation existed between the value of the ratio and the severity of the liver disease as judged histologically, with values of the ratio appearing to reflect histological change irrespective of the patient's clinical condition. There was no significant diurnal variation in the value of the ratio. Lowering of this plasma amino acid ratio appears to be secondary to liver disease and quite independent of the presence of hepatic encephalopathy.
 ...
PMID:Plasma ratio of valine, leucine and isoleucine to phenylalanine and tyrosine in liver disease. 73 76

Previous work from this laboratory has suggested that the plasma amino acid pattern, known to be deranged in hepatic encephalopathy, may be related causally. In order to test this hypothesis, 23% dextrose and a special amino acid solution whose components were calculated to normalize the plasma amino acid pattern were infused in 11 patients, eight with chronic cirrhosis and acute exacerbation (Group 1) and three patients with fulminant hepatitis (Group 2), in amounts of up to 120 Gm. of protein equivalent per 24 hours. Plasma amino acids were abnormal but different in both groups. In Group 1 (cirrhosis) changes in plasma amino acid pattern including elevated phenylalanine, tyrosine, glutamate, aspartate, and methionine and decreased valine, leucine, and isoleucine. In Group 2 all amino acids were elevated, with the exception of the branched chains which were normal. Hepatic encephalopathy improved in all patients in Group 1 and in one of three patients in Group 2 following the infusion. The ratio (see article) showed an excellent correlation with a grade of encephalopathy. When this ratio, previously 1.0 in the presence of encephalopathy, returned to the normal value near 3.0 to 3.5, encephalopathy improved. An excellent correlation was obtained between the ratio and the grade of encephalopathy and was dose related as well. The results suggest that different amino acid patterns in hepatic encephalopathy of differing etiologies require treatment modalities which may differ for the two types of encephalopathy. Whereas amino acid infusion appears to be a valuable, efficacious way of providing nutrition in treating hepatic encephalopathy in patients with cirrhosis and acute deterioration and coma, other means of therapy such as plasms "laundering" appear to be necessary in patients with fulminant hepatitis.
 ...
PMID:The effect of normalization of plasma amino acids on hepatic encephalopathy in man. 81 29

A male infant with type I hereditary tyrosinemia developed a phenylalanine-tyrosine deficiency syndrome after receiving a synthetic diet which was low in these amino acids. The syndrome was characterized by growth failure, anorexia, lethargy, and hypotonia. Hypophenylalaninemia and hypotyrosinemia were discovered. The blood concentration of most other amino acids were increased. Supplementation of the patient's diet with phenylalanine and tyrosine resulted in a prompt and dramatic reversal of both clinical and biochemical abnormalities. Dietary therapy had no effect on the child's hepatic cirrhosis.
 ...
PMID:Phenylalanine-tyrosine deficiency syndrome as a complication of the management of hereditary tyrosinemia. 83 7

The metabolism of intravenously administered L-phenylalanine has been studied in 13 patients with cirrhosis of the liver and in 17 control subjects. The decline in the plasma phenylalanine concentration followed a biexponential curve and the kinetics could be evaluated assuming a two-compartment model. The volume of the central compartment was reduced in the cirrhotic patients, reflecting a diminished liver pool size. The total phenylalanine clearance was lower in the cirrhotic patients, due mainly to a reduction of the liver cell mass or to changes in the intrahepatic membrane permeability and only to a minor extent to a reduced hepatic blood flow. The elimination rate constant from the central compartment was similar in both groups, suggesting that the remaining liver cells, had a normal capacity to hydroxylate phenylalanine to tyrosine. There was considerable overlapping in the kinetic parameters between the two groups, and even in patients with well established cirrhosis an apparently normal phenylalanine metabolism was observed.
 ...
PMID:Kinetics of intravenous administered L-phenylalanine in patients with cirrohosis of the liver. 88 70


1 2 3 4 5 6 7 8 9 10 Next >>