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)

We have measured the activity of S-adenosyl-L-methionine synthetase, the ratio between the high- and low-molecular-weight forms of this enzyme and the concentration of S-adenosyl-L-methionine in liver biopsies from a group of controls (n = 6) and in six cirrhotics (five posthepatitic and one alcoholic). The total activity of S-adenosyl-L-methionine synthetase was markedly reduced in cirrhosis (37.5% of that found in the control group). This was due to a specific reduction in the high-molecular-weight S-adenosyl-L-methionine synthetase in the group of cirrhotics (73.9 pmoles per min per mg protein) when compared with that observed in controls (460.3 pmoles per min per mg protein). Despite this reduction in the rate of synthesis of S-adenosyl-L-methionine (the high-molecular-weight form of the enzyme is 15 times more active than the low-molecular-weight form at physiological concentration of substrates), the concentration of this metabolite was the same in the control group (17.3 +/- 2.6 microM) and in the group of cirrhotics (17.8 +/- 3.1 microM). To explain these findings, it is postulated that in human liver, where the concentration of S-adenosyl-L-methionine is lower than the Km values of a variety of enzymes that use this metabolite (around 50 to 100 microM), a reduction in the synthesis of S-adenosyl-L-methionine is compensated by a reduction in the rate of utilization of this molecule without affecting the intrahepatic concentration of S-adenosyl-L-methionine.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Specific loss of the high-molecular-weight form of S-adenosyl-L-methionine synthetase in human liver cirrhosis. 319 66

Methionine enkephalin and catecholamines were measured in carefully collected plasma samples from 25 patients with cirrhosis and ascites, and 25 with cirrhosis without ascites, 15 disease and 15 healthy controls. Methionine enkephalin was invariably raised in the ascites group, the median value being 4.6-6.9 times that of the other three groups. Similarly, in the ascites group, median noradrenaline was increased 2.5-4.2 and median adrenaline 1.8-2.5 times that of the other groups. Plasma methionine enkephalin is considerably raised in patients with cirrhotic ascites and has actions which could enable it to be an initiating factor of ascites formation.
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PMID:Is ascites caused by impaired hepatic inactivation of blood borne endogenous opioid peptides? 319 89

Increased sympathetic tone and adrenal medullary activity in hepatic cirrhosis may promote portal hypertension. We suggest that they may be imperfect homeostatic mechanisms attempting to maintain systemic arterial pressure in response to chronic vasodilatation and that small, endogenous opioid peptides may play a part in this vasodilatation. As initial investigation of this hypothesis, we measured noradrenaline (an indicator of sympathetic tone), adrenaline and methionine enkephalin in the plasma of patients with cirrhosis with oesophageal varices which had or had not bled previously, patients with cirrhosis without varices, patients with acute liver disease and controls. In patients with cirrhosis, noradrenaline, adrenaline and methionine enkephalin were all greatest in those with oesophageal varices which had previously bled. In this group, noradrenaline correlated strongly with the widely used prognostic guide, Pugh's modification of Child's classification. In patients with acute liver disease, methionine enkephalin and adrenaline were increased six- and four-fold respectively. However, noradrenaline was normal, suggesting that increased sympathetic tone in cirrhosis may develop gradually. The use of opioid antagonists may enable determination of whether elevated plasma opioid peptides in cirrhosis stimulate the increase in sympathetic tone and plasma adrenaline, and promote bleeding oesophageal varices.
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PMID:Do increased catecholamines and plasma methionine enkephalin in cirrhosis promote bleeding oesophageal varices? 326 78

We have measured the activity S-adenosyl-L-methionine synthetase in liver biopsies from a group of controls (n = 17) and in 26 cirrhotics (12 alcoholic and 14 posthepatic). The activity of this enzyme was markedly reduced in the group of cirrhotics (285 +/- 32 pmoles per min per mg protein) when compared with that observed in controls (505 +/- 37 pmoles per min per mg protein). No differences in S-adenosyl-L-methionine synthetase was observed between both groups of cirrhotics. Similarly, a marked reduction in the activity phospholipid methyltransferase was also observed in liver biopsies from the same group of cirrhotics (105 +/- 12 pmoles per min per mg protein) when compared with the control subjects (241 +/- 13 pmoles per min per mg protein). Again, no difference in the activity of this enzyme was observed between both groups of cirrhotics. These results indicated a marked deficiency in the metabolism of S-adenosyl-L-methionine in cirrhosis.
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PMID:S-adenosyl-L-methionine synthetase and phospholipid methyltransferase are inhibited in human cirrhosis. 333 21

Carnitine (beta-hydroxy-gamma-N-trimethylaminobutyric acid) is required for transport of long-chain fatty acids into the inner mitochondrial compartment for beta-oxidation. Widely distributed in foods from animal, but not plant, sources, carnitine is also synthesized endogenously from two essential amino acids, lysine and methionine. Human skeletal and cardiac muscles contain relatively high carnitine concentrations which they receive from the plasma, since they are incapable of carnitine biosynthesis themselves. Since the discovery of a primary genetic carnitine deficiency syndrome in 1973, carnitine has become the subject of extensive research. It is now recognized that carnitine deficiency may also occur secondary to genetic disorders of intermediary metabolism as well as to a variety of clinical disorders, including renal disease treated by hemodialysis, the renal Fanconi syndrome, cirrhosis, untreated diabetes mellitus, malnutrition, Reye's syndrome, and certain disorders of the endocrine, neuromuscular, and reproductive systems. Administration of the anticonvulsant valproic acid and total parenteral nutrition may also induce hypocarnitinemia. In many instances, the physiological implications of secondary carnitine deficiency have not been resolved. However, evidence for a specific carnitine requirement for the newborn, especially if preterm, is accumulating. Moreover, carnitine administration may have a favorable effect on some forms of hyperlipoproteinemia. Carnitine, now recognized as a conditionally essential nutrient, is a significant factor in preventive medicine.
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PMID:Carnitine: an overview of its role in preventive medicine. 353 87

We measured fasting plasma amino acids in 26 children aged 6 months to 5 years with extrahepatic biliary atresia and cirrhosis and compared them with fasting values in 95 normal control children aged 4 months to 12 years. We found that the cirrhotic children had elevations of total free plasma amino acids implying reduced hepatic metabolism of amino acids and that the molar ratio of the branched chain amino acids (isoleucine, leucine, and valine) to the aromatic amino acids (phenylalanine and tyrosine) was significantly depressed. Methionine was also markedly elevated, and taurine concentrations were significantly decreased. Manipulation of the amino acid distribution in dietary protein to normalize plasma amino acids prior to orthotopic hepatic transplantation may be helpful in improving amino acid utilization.
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PMID:Amino acid abnormalities in infants with extrahepatic biliary atresia and cirrhosis. 368 71

Amino acid levels were measured in the plasma and ascitic fluid of 13 alcoholic patients with liver cirrhosis and of 14 normal controls. The plasma aromatic amino acids of the alcoholic patients were not statistically different from those of the control subjects, whereas the levels of branched-chain amino acids were reduced (P less than 0.05). The values for the ratio of the muscle/liver metabolized amino acids (valine + isoleucine + leucine)/(phenylalanine + tyrosine + methionine) were statistically lower in the cirrhotic patients both in plasma and ascitic fluid (P less than 0.05). The amino acid levels in the ascitic fluid of the cirrhotic patients were slightly lower than those in the plasma of the same patients and the values for the muscle/liver metabolized amino acid ratio were similar in plasma and ascitic fluid. Aspartic acid, glutamic acid and glycine levels were higher among the cirrhotic patients (P less than 0.05). Cirrhotic patients present an alteration in amino acid metabolism which creates a different amino acid pattern in both plasma and ascitic fluid. The significance of the proposed ratio and its possible relation to hepatic failure are discussed.
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PMID:Amino acid patterns in the plasma and ascitic fluid of cirrhotic patients. 383 4

Evidence from several sources suggest that blood-brain transport of the large neutral amino acids (NAA) is abnormal in animals with a portacaval anastomosis (PCA) and in patients with liver cirrhosis and portal-systemic shunting and encephalopathy, but the underlying mechanisms are unknown. After PCA, the concentration of glutamine (Gln) in brain is markedly increased as a by-product of cerebral ammonia detoxification, and the rate of efflux of Gln from brain is also increased. The following studies were undertaken to clarify the relationships among plasma and brain concentrations of NAA after PCA in rats and to examine the relationship of brain Gln concentration to plasma and brain NAA concentrations. After PCA plasma phenylalanine, tyrosine and histidine were elevated and leucine, isoleucine and valine were lowered. In brain, phenylalanine, tyrosine, histidine and methionine were markedly elevated after PCA and their concentrations in brain far exceeded the concentrations in plasma. Analyses of single, partial and multiple correlations of plasma NAA ratios expressed as plasma competitor function (PCF), brain NAA and brain Gln showed significant correlations between PCF nd brain NAA in shunted rats. A better correlation was found between brain NAA and brain Gln. Correlation coefficients obtained from multiple correlation analysis equalled or exceeded those obtained in the partial correlation or in the single correlation, suggesting that the effects of PCF and brain Gln on brain NAA were separate and additive. Gln was shown to compete with other NAA for blood brain transport by inhibiting brain 14C phenylalanine uptake.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Relationship of brain glutamine and brain neutral amino acid concentrations after portacaval anastomosis in rats. 393 Feb 56

Administration of total parenteral nutrition (TPN) solutions high in branched chain amino acids (BCAA) is thought to improve metabolic support during stress. This prospective, randomized, double blind study compared 45 per cent BCAA with 25 per cent BCAA in 12 patients. Seven patients had multiple trauma; two, gastrointestinal surgery; one, pancreatitis; and two, cirrhosis. The TPN regimen was 1.0-1.5 gm/kg/day amino acids and 30-45 glucose kcal/kg/day. The BCAA formula used was high in isoleucine and valine, but not leucine. Amino acid plasma levels, blood chemistries, 3-methylhistidine excretion, and nitrogen balance were studied. Control studies showed negative nitrogen balance (-7.1 +/- 2.9 gm) (mean +/- SEM), elevated insulin (61 +/- 21 microunit/ml), and elevated 3-methylhistidine (3MH) excretion (688 +/- 309 micromol); plasma leucine (93 +/- 11 nmol/ml) and isoleucine (37 +/- 23) were low, and valine (155 +/- 20) was elevated. Plasma methionine (40 +/- 9) and tyrosine (70 +/- 12) were high normal. Phenylalanine (85 +/- 5) was elevated. Both groups showed increased nitrogen excretion and positive nitrogen balance during the study (25 per cent, 2.0 +/- 1.4 gm/day; 45 per cent, 1.2 +/- 2.6 gm/day). Three-methylhistidine excretion changed little in either group (557 +/- 149, 414 +/- 91), insulin rose (135 +/- 27, 65 +/- 19), and plasma leucine (82 +/- 4, 71 +/- 9) changed little. Plasma isoleucine (51 +/- 3, 155 +/- 16) and valine (173 +/- 11, 691 +/- 23) both rose, more in the 45 per cent group. Methionine (67 +/- 12, 37 +/- 4) and tyrosine (51 +/- 6, 50 +/- 10) changed little.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Comparison of total parenteral nutrition with 25 per cent and 45 per cent branched chain amino acids in stressed patients. 393 93

Patients with hepatic cirrhosis often are malnourished and wasted. If portal-systemic encephalopathy (PSE) develops, restriction of dietary protein in an attempt to treat encephalopathy may further promote negative nitrogen balance. There is considerable interest in providing nutritional supplements to patients with cirrhosis and PSE which would lead to improvement in nitrogen balance while improving or at least not worsening PSE. Amino acid supplements designed to correct the abnormal amino acid pattern characteristically found in patients with cirrhosis and PSE are under investigation as potential therapeutic agents. The levels of the branched chain amino acids (BCAAs) are decreased in almost all patients with cirrhosis and PSE. The exact mechanism for the reductions in BCAA concentrations is unknown. Furthermore, aromatic amino acids (AAA) and methionine (MET) concentrations are usually increased in these patients. It has been suggested that BCAAs and neutral amino acids compete for transport across the blood-brain barrier and that a decrease in BCAA concentrations promotes entrance of neutral amino acids into the brain. Aromatic amino acids, MET, and their derivatives may have a role in the production of PSE. These observations have increased interest in the potential therapeutic benefit of administering BCAAs to patients with cirrhosis and PSE in order to decrease the entrance of putative toxins into the brain. Treatment trials using BCAAs alone or in solutions containing other amino acids in patients with cirrhosis and PSE have given conflicting results. In one trial, there appeared to be less PSE induced by a BCAA-enriched solution when compared to equinitrogenous dietary protein. However, other controlled studies have not demonstrated any advantage to the addition of BCAAs as compared to placebo with regards to reducing mortality or improving cerebral function in patients with acute cirrhosis and PSE. Some of the differences in study outcomes may relate to the patient population evaluated; the type, amount, and duration of treatment; and whether other therapy was administered. BCAA supplements may also be useful in minimizing or reversing the catabolic state characteristic of patients with cirrhosis. A reduction of increased urinary 3-methylhistidine excretion by infusions of BCAAs in cirrhotic patients suggests an anticatabolic effect. These potential anticatabolic effects of BCAAs are most interesting and deserve further study.
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PMID:Branched chain amino acid therapy in liver disease. 393 6


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