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Query: UMLS:C0023890 (cirrhosis)
 42,195 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ammonia is generated from a large number of metabolically important reactions. Despite its central importance in whole body nitrogen homeostasis excess ammonia is neurotoxic and its concentration must be kept low. Ammonia generated in most extrahepatic tissues is detoxified by incorporation into glutamine (amide). This glutamine may be used in a number of biosynthetic reactions (e.g. in pyrimidine synthesis). Alternatively, as a means of maintaining nitrogen balance, glutamine may be released to the blood. Resting skeletal muscle is particularly important 1) as a "sink" for removal of blood ammonia, and 2) as a major source of circulating glutamine. However, during vigorous exercise skeletal muscle may become a net contributor of ammonia to the blood. A few tissues and cell types (e.g. lymphocytes, macrophages, enterocytes, colonocytes, thymocytes, fibroblasts, bone) and tumors exhibit marked rates of glutamine utilization. In the kidney, glutamine is an important source of urinary ammonia. Ammonia generated from 1) the breakdown of nitrogenous substances in the gut, and 2) from the use of glutamine as a metabolic fuel in the small intestine, is taken up by the liver wherein it is detoxified by conversion to urea and to a lesser extent, glutamine. Some portal vein glutamine acts as a source of urea nitrogen. Ultimately, however, most excess ammonia nitrogen is detoxified indirectly (via glutamine (blood)----glutamine (small intestine)----ammonia (portal vein) or directly in the liver as urea. Portal-systemic shunting of blood, as occurs in chronic cirrhosis of the liver or following the surgical construction of a portacaval shunt results in portal blood bypassing the normal ammonia detoxification machinery of the liver. Under this condition blood ammonia levels rise markedly, increasing the burden on extrahepatic tissues, such as skeletal muscle, brain, and kidney, in maintaining ammonia homeostasis. The most commonly employed animal model of human liver disease is the rat in which an end-to-side portacaval shunt (PCS) has been surgically constructed. Brain glutamine synthetase activity is not increased in PCS rats and in some areas of the brain there may even be a decrease in activity. The brain glutamine synthetase appears to be working at near maximal capacity. Thus, the PCS rats exhibit profound neurological dysfunction when administered ammonium salts in amounts easily tolerated by normal animals. Because of the limited capacity of brain to remove excess ammonia, a rational approach to the treatment of patients with liver disease should include a regimen directed toward lowering the associated hyperammonemia.
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PMID:Ammonia metabolism in normal and portacaval-shunted rats. 210 90

To assess the metabolic characteristics of cirrhotic hepatocytes, a primary culture of hepatocytes was established using rat liver induced cirrhosis by CCl4 administration. Using this system, cell responsiveness to different metabolic and excretory stimuli was investigated and compared with a primary culture of normal healthy rat hepatocytes. Cirrhotic hepatocytes showed reduced protein synthesis in response to insulin and reduced urea synthesis in response to glucagon. However, DNA synthesis stimulated by insulin and EGF was significantly enhanced in cirrhotic hepatocytes. No significant difference was observed in the fluorescein diacetate excretion rate. Cirrhotic hepatocytes showed impairment of antipyrine metabolism and conjugation and excretion of unconjugated bilirubin. These results suggest indirectly that cirrhotic hepatocytes may be less functionally mature than normal healthy hepatocytes.
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PMID:[Studies on metabolic characteristics of cirrhotic rat hepatocytes using primary culture]. 221 64

A three-compartment model was used to analyse the urea response to an alanine infusion in control subjects and patients with liver cirrhosis. Discriminant analysis showed a good separation between model coefficients of the two groups. A single parameter was derived, able to quantify the liver functional capacity. The method provides a useful diagnostic tool in patients with liver disease.
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PMID:Mathematical model to analyse urea synthesis following alanine infusion in control subjects and in patients with liver cirrhosis. 224 31

The authors studied gastric juice ammonia and urea nitrogen levels to determine how they are altered by gastric Campylobacter pylori (CP) infection. Patients with chronic gastritis (20), peptic ulcer (24), hepatic cirrhosis (10), chronic renal failure (13), or gastric remnant (20) were included. Endoscopic biopsy specimens stained with the Warthin-Starry stain were evaluated for the presence of CP. Blood and gastric juice analysis was performed for 11 of the patients with chronic renal failure and 37 patients from the remaining groups. CP was identified in gastric biopsies from 50 of 87 (57.5%) patients, including 87.5% with peptic ulcer and 40-50% of those with chronic gastritis, cirrhosis, chronic renal failure, or gastric remnant. CP infection had no effect on blood urea nitrogen or blood ammonia levels in any group of patients. The urea nitrogen level of gastric juice was higher in patients with chronic renal failure than in other groups but was not related to CP infection. CP infection was associated with a significant increase in gastric juice ammonia levels, both in patients with chronic renal failure (23.3 mmol/L vs. 2.90 mmol/L; [P less than 0.05]) and in other groups (5.48 mmol/L vs. 1.26 mmol/L [P less than 0.0001]). The authors conclude that elevation of gastric juice ammonia level is an indicator of gastric CP infection.
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PMID:The gastric juice urea and ammonia levels in patients with Campylobacter pylori. 237 72

In hypoosmolar hyponatremia, vasopressin is commonly observed to be less than maximally suppressed. This is attributed to the presence of nonosmolar vasopressin stimuli. However, the exact relationship of nonsuppressed antidiuretic hormone to specific circulatory parameters is controversial. Therefore, in the present study, we examined this question in 100 hypoosmolar hyponatremic patients in the Department of Medicine. Despite plasma hypoosmolality, vasopressin was found to be measurable in 92% of patients. Seventy patients suffered from edematous disorders (congestive heart failure, cirrhosis) or volume contraction per se; in these patients we observed unequivocal, though indirect, evidence of advanced circulatory alterations. These were associated with hyponatremia and nonsuppressed vasopressin. However, the latter could not be related directly to a specific circulatory parameter such as mean arterial blood pressure, creatinine clearance, plasma renin activity (PRA), norepinephrine, or aldosterone. However, patients with nondetectable vasopressin (n = 8) differed significantly from those with high vasopressin concentrations (n = 8: PADH greater than 9 pg/ml); in the latter, pulse rate (104 +/- 3 vs. 82 +/- 5 beats/min), plasma urea concentration (90 +/- 5 vs. 32 +/- 5 mg/dl), plasma urate concentration (7.2 +/- 0.8 vs. 3.6 +/- 0.8 mg/dl), and PRA (36 +/- 7 vs. 9.5 +/- 4.6 ng AI/ml/h) were all significantly higher than in the former. It is concluded that, in hyponatremia, the relationship between circulatory impairment and vasopressin is complex.
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PMID:Vasopressin in hyponatremia: what stimuli? 243 81

The authors conducted a prospective, longitudinal, multicentre study in patients with liver cirrhosis; a total of 192 patients were on follow-up, of this number 125 died during the study. Mean age, 56 years, was markedly more advanced in the dead; men prevailed among the patients. Duration of complaints and the interval since the diagnosis had been established was shorter in the dead than in those alive; a positive HBs antigen was likewise more often present in the former. Clinical and laboratory parameters in this group were assessed with a view to the differences between the dead and those alive and with a view to the time course of changes in these differences. Multifactorial discriminative analysis of these data for various intervals before death was also performed. The most pronounced differences were noted in clinical manifestations and laboratory signs of hepatic insufficiency, especially in the presence and degree of ascites, jaundice, encephalopathy, and in the values of bilirubin, Quick' test and blood albumin levels; thus the degree of liver insufficiency appears to be the most important prognostic marker in patients with liver cirrhosis. Moreover, a significant increase in urea and leucocyte levels was found in the terminal stages of the disease. Ascites, encephalopathy and a progressive increase in serum bilirubin levels seem to be the best markers for discriminative analysis of prognosis for the last six months of life. Results of this study, while confirming some findings by other authors, offer also new insights into the whole issue.
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PMID:[A prospective prognostic study of liver cirrhosis]. 267 84

Ammonia clearance, portal blood ammonia, and amino acid concentrations were studied during induction of cirrhosis by carbon tetrachloride in rats. Exposure to CCl4 vapors twice weekly for 7-16 weeks doubled orotic acid excretion. If exposure was discontinued for 7 days, the orotic acid excretion decreased despite the presence of cirrhosis proven histologically. Replacement of dietary casein with soybean protein eliminated the CCl4-induced orotic aciduria in growing rats but not in adults. Supplementation of casein with 1.5% arginine did not prevent CCl4-induced orotic aciduria. [14C]Orotate uptake into RNA and DNA of liver was not impaired. Perfusion of livers of cirrhotic animals with ammonia concentrations between 0.2 and 3.0 mM revealed no significant decreases in urea synthesis rates due to cirrhosis and no increase in the tendency to make orotic acid at a given ammonia concentration. However, ammonia uptake by cirrhotic livers was significantly reduced, resulting in higher ammonia concentrations in the effluent when there was moderate-to-severe cirrhosis. Portal blood samples taken from rats exposed to CCl4 had higher ammonia concentrations as cirrhosis worsened. The results lend support to the "intact hepatocyte" hypothesis of cirrhosis which attributes metabolic abnormalities to intrahepatic shunts.
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PMID:Orotic acid overproduction in experimental cirrhosis of rats. 272 54

Zinc is an essential trace metal in the body. It's deficiency is known to induce skin lesions and hypogeusia. It also has an important role as a core element of various enzymes. In the liver, ornithine carbamyl transferase (OCT), a metal enzyme in the urea cycle, where ammonium is metabolized, contains zinc. The previous report showed that patients with liver cirrhosis (LC) were in a state of zinc deficiency. The present study investigated the possible involvement of hypozincemia in the functional failure of the urea cycle in hepatic insufficiency in rats with experimental LC. Compared with control rats, rats with LC showed a decrease in the serum zinc concentration (LC 118.6 +/- 33.7 micrograms/dl: control 161.6 +/- 13.9 micrograms/dl p less than 0.05), a decrease in the zinc content of the liver (LC 81.4 +/- 16.3 micrograms/g DW: control 108.1 +/- 6.9 micrograms/g DW p less than 0.01), a decrease in the OCT activity in the liver (LC 24.7 +/- 4.0 U/mg prot: control 42.4 +/- 3.8 U/mg prot p less than 0.01), and an increase in serum ammonium (LC 87.2 +/- 38.5 micrograms/dl: control 38.5 +/- 10.6 micrograms/dl p less than 0.05). There was a significant correlation between the zinc content and OCT activity in the cirrhotic liver (r = 0.6075, p less than 0.01). In addition, to evaluate the effect of dietary zinc on rats with LC, we divided these rats into two groups and fed them a diet with or without zinc for 4 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Studies of metabolic abnormality of zinc in chronic liver diseases (report 2)--basic examination of its effects on pathophysiology]. 273 94

We produced moderately severe, inactive micronodular cirrhosis in rats using CCl4 and measured the urea cycle enzyme activities in liver after feeding a 15% casein diet for 1 week and again after a 60% casein diet for 1 week. There was no deficiency of any of the five urea cycle enzymes in cirrhotic livers of rats pair-fed the 15% casein diet. Argininosuccinate synthetase and carbamyl phosphate synthetase activities were lower than in non-pair-fed controls by some baselines. All five enzymes in cirrhotic livers were induced 1.5- to 3-fold by the high-protein diet expressed as units per 100 gm of rat. The level of carbamyl phosphate synthetase activity was lower in the livers of rats pair-fed the 60% casein diet than in control livers based on wet weight, collagen-free protein and DNA, but the activities were equal expressed as units per 100 gm of rat. This example of CCl4-induced cirrhosis in the rat does not serve as a good model for human cirrhosis, in which the urea cycle enzymes are reported to be decreased in activity.
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PMID:Urea cycle enzyme activities are normal and inducible by a high-protein diet in CCl4 cirrhosis of rats. 292 Sep 93

Soluble interleukin 2 receptors (sIL 2R) in the sera of patients with viral liver diseases were quantified with a solid-phase enzyme immunoassay using two monoclonal antibodies against the receptors. The sIL 2R levels in patients with acute hepatitis, chronic hepatitis, liver cirrhosis and hepatocellular carcinoma were significantly higher than those in control subjects. In acute hepatitis patients, the high levels of sIL 2R observed during the florid stage returned to normal during remission. Levels in patients with chronic active hepatitis were significantly higher than in those with chronic persistent and lobular hepatitis, and levels observed during the exacerbation phase of chronic hepatitis were higher than they were during remission. Thus, in chronic hepatitis, sIL 2R levels increased in proportion to the inflammatory activity, and correlated well with serum transaminase (glutamic oxaloacetic transaminase: SGOT, glutamic pyruvic transaminase: SGPT) activities, but not with blood urea nitrogen or creatinine concentrations. In patients with a high degree of focal and piecemeal necrosis, serum sIL 2R levels increased further during recombinant interleukin 2 therapy. In post-hepatitic liver cirrhosis and hepatocellular carcinoma, sIL 2R levels correlated with serum cholinesterase and creatinine concentrations, but not with transaminase activities. Measurement of serum sIL 2R levels in patients with liver disease but without renal injury, may help in the diagnosis of inflammation in hepatitis, a process in which interleukin 2 may participate.
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PMID:Increased serum soluble interleukin 2 receptor levels in patients with viral liver diseases. 306 11


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