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Query: UMLS:C0085584 (encephalopathy)
 18,178 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The 15N-tracer technique gives new opportunities to medical research for investigation of normal and pathological nitrogen metabolism. Analysis of 15N kinetic data derived from total nitrogen excretion in the urine allows to calculate quantitatively certain parameters of protein synthesis and protein metabolism. At the same time analysis of serum samples will allow measurement of 15N-nitrogen incorporation into particular protein or non-protein fractions of the plasma. In the study reported here patients with different liver parenchyme lesions (acute hepatitis, chronic active hepatitis, biliary obstruction, cirrhosis of the liver, hepatic coma) were investigated with a standardized 15N-tracer method developed by us. It could be shown, that protein turnover in patients with liver insufficiency is significantly decreased as compared to healthy persons. Decrease of protein synthesis is associated with a still more pronounced decrease of protein catabolism. There are significant differences in dynamics of 15N in patients with hepatic coma as compared to other patients with liver parenchyme disease without portal encephalopathy. Nevertheless, even in hepatic coma 15N incorporation into plasma proteins can be shown. Differences in the 15N elimination kinetics of the non-protein pool between patients with chronic active hepatitis, biliary obstruction and hepatic coma could be found.
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PMID:[Protein turnover in liver failure--determination using the stable isotope 15N]. 650 88

A symptomatic elevation in plasma ammonium concentration, termed hyperammonemia, is associated with numerous congenital and acquired conditions (Table 11). In some cases, such as urea cycle disorders, ammonia is the principal toxin. In other instances, such as portal systemic encephalopathy, it is but one of a number of metabolic disturbances, However, in either case hyperammonemic episodes should be treated aggressively to prevent coma, subsequent brain damage, or death. This involves restricting protein intake, providing adequate calories, and giving agents that remove accumulated nitrogen. Long-term therapy relies on diagnosing the specific disease rate. This rarely requires invasive procedures such as liver biopsy. In most cases measurement of plasma amino acids and urinary organic acids will identify the defect. Treatment involving restriction of nitrogen intake, vitamin supplementation, or stimulation of alternative pathways of waste nitrogen excretion can then be instituted. Early therapy, especially in patients with neonatal-onset hyperammonemia, is imperative to avoid severe brain damage. On this basis, the plasma ammonium level should be determined in virtually every newborn with lethargy, hypotonia, poor feeding, seizures, and/or respiratory distress of unclear origin (Table 12).
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PMID:Hyperammonemia. 651 17

Plasma levels of six short-chain fatty acids (SCFA) were measured in 23 Reye's syndrome patients. In sequential measurements, only propionic acid correlated closely with neurologic severity. Although admission SCFA levels were slightly elevated, there were no significant differences between patients grouped by severity of encephalopathy. Admission SCFA did not predict neurologic outcome; also, they correlated poorly with admission blood ammonia, amino acid nitrogen, and lactate.
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PMID:Short-chain fatty acids and encephalopathy of Reye's syndrome. 653 50

Twenty-two patients with cirrhosis and acute encephalopathy who were refractory to medical therapy were entered into a randomized, double-blind prospective trial. This trial consisted of either neomycin or a modified amino acid solution rich in branched chains and low in aromatic amino acids and methionine (F080) in the presence of isocaloric amounts of dextrose. The groups were indistinguishable from each other by clinical or laboratory criteria; they were primarily patients who had undergone operation and they would tolerate only 30 gm of oral protein or intravenous standard amino acids. The group receiving F080 had a faster and more complete improvement in encephalopathy. This improvement correlated with the plasma molar ratio and occurred with a lower mortality rate. In addition, the patients also tolerated twice the amino acid load without encephalopathy and were in positive nitrogen balance. Modified metabolic support is effective in the setting of acute liver failure in chronic cirrhosis, particularly in patients who have undergone operation.
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PMID:Cirrhosis, encephalopathy, and improved results with metabolic support. 662 61

A randomized study was conducted in 37 hospitalized patients at six cooperating hospitals in which protein-intolerant cirrhotic patients were fed increasing amounts of either dietary protein or a branched-chain enriched amino acid solution (BCAA) until they attained an intake of 80 gm protein per day or equivalent or until they developed stage 2 encephalopathy. All patients initially received 20 gm of dietary protein for 1 week, after which 20 gm of protein or BCAA were added weekly. Nitrogen balance improved from negative to positive in all patients in whom it was measured and increased equally in both groups. Seven of the 20 patients in the protein group and 1 of 17 in the BCAA group developed encephalopathy of stage 2 or greater (p less than 0.05). Changes in each component of the portal-systemic encephalopathy syndrome were compared, and differences were statistically significant for mental status grade (p less than 0.01), asterixis (p less than 0.05), Portal-systemic encephalopathy index (p less than 0.01), but insignificant for Number Connection Test, EEG or ammonia. Plasma amino acid profiles showed an increase in BCAA in the study group. Thus, oral BCAA supplements appear to induce positive nitrogen balance to approximately the same degree as an equivalent amount of dietary protein without inducing encephalopathy as frequently.
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PMID:Comparison of dietary protein with an oral, branched chain-enriched amino acid supplement in chronic portal-systemic encephalopathy: a randomized controlled trial. 670 2

Whole body calcium, phosphorus and nitrogen have been measured by in vivo neutron activation analysis in patients with chronic renal failure, including 9 with dialysis encephalopathy. Aluminium was also activated by this procedure, but to the same radioactive product as that from phosphorus: its presence was therefore detected as an increase in the apparent total body phosphorus above that expected for a person with the same calcium content. Patients with dialysis encephalopathy had slightly more apparent phosphorus than others with chronic renal failure, although the difference was not statistically significant. This difference corresponded to an excess of aluminium not greater than 3.3 g(95% confidence limit) which places an upper limit on excess aluminium accumulation in this condition.
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PMID:Whole body aluminium in chronic renal failure and dialysis encephalopathy. 677 55

The method of constant infusion of U14C tyrosine tracer was used to measure whole body protein turnover in 24 patients with liver disease of varying severity. Whilst on a basic diet of glucose alone (5 g/hr), protein turnover and endogenous breakdown was significantly elevated in patients with cirrhosis and fulminant hepatic failure (F.H.F.), breakdown rising to 700 g/d greater than normal in F.H.F. In addition plasma aromatic aminoacids were significantly elevated and positively associated with the increases in endogenous protein breakdown (r = 0.78, p less than 0.05). Fourteen patients had a second infusion after dietary supplementation with either complete aminoacids (3 g/hr, n = 8) or branched chain aminoacids (BCAA, 4 g/hr, n = 6). The complete mixture did not worsen encephalopathy, improved the plasma aminoacid pattern, reduced protein breakdown and resulted in positive aminoacid balance. The BCAA supplements significantly reduced protein oxidation and endogenous breakdown. The results indicate that protein restriction in cirrhosis and fulminant hepatic failure will not significantly affect the load of aminoacids on the liver, nor their accumulation in plasma. Nutritional support of such patients should therefore include 40 - 60 g. protein per day to prevent protein depletion, and hypertonic glucose and insulin to suppress catabolism. BCAA supplementation may play a useful supportive role in increasing the utilisable nitrogen content of the diet and further suppressing catabolism.
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PMID:Protein turnover in acute and chronic liver disease. 679 9

Hepatic-Aid is purported to ameliorate encephalopathy and promote positive nitrogen balance in protein-intolerant, cirrhotic patients by correcting their imbalanced amino acid profile. This study evaluated Hepatic-Acid by comparing a 50-g Casein diet with an identical diet with 20-g Casein/30-g Hepatic-Aid per day in a cross-over study. Four patients with biopsy-proven stable cirrhosis, encephalopathy, and under-nutrition were studied. Each study period included three days of equilibration and eight days of metabolic balance, with the following measured at baseline and on balance days 5 and 8: routine biochemistry, fasting ammonia, psychometric tests, EEG, and plasma amino acid profiles. There was no significant change in clinical status, routine biochemistry, fasting ammonia, psychometrics or EEG between the two study periods. Mean (+/-SD) nitrogen balance on the Casein diet at 1.5 +/- 1.5 g/day was not significantly different from that on the Hepatic-Aid diet at 1.5 +/- 1.2 g/day. Plasma amino acid profiles showed a significant fall (p less than 0.05) in fasting and intraprandial tyrosine (tyr) and phenylalanine (phe) on Hepatic-Aid, but only intraprandial leucine (leu), isoleucine (ile), and valine (val) were significantly increased (p less than 0.05) on Hepatic-Aid. The ratio leu + ile + val to tyr + phe was significantly increased (p less than 0.05) on Hepatic-Aid. It is concluded that Hepatic-Aid, as given in this study, maintains N balance similar to Casein, alters the amino acid profile towards normal, but does not ameliorate encephalopathy.
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PMID:Comparison of the effects of Hepatic-Aid and a Casein modular diet on encephalopathy, plasma amino acids, and nitrogen balance in cirrhotic patients. 683 Mar 37

Nine patients on long-term hemodialysis with dialysis encephalopathy were studied, with sex matched control subjects for eight of the patients. Each patient with dialysis encephalopathy and control subject were contemporaries in a similar dialysis environment. Rib and other fractures were found in excess in the patients with dialysis encephalopathy (p less than 0.005 and p less than 0.01). These patients had less radiographic hyperparathyroid bone disease, and no more osteopenia as measured by metacarpal thickness than did their control counterparts. Severe osteomalacia was documented by bone biopsy in four of te patients. In a retrospective review of clinical, biochemical and pharmacologic differences, the patients with dialysis encephalopathy were significantly older at the start of dialysis (45.6 years versus 38.6 years, p less than 0.02) and had higher mean concentrations of blood urea nitrogen (BUN) and lower serum hemoglobin in the first year of dialysis than the control subjects. Blood pressure weight, creatinine, calcium, phosphate, alkaline phosphatase and a number of transfusions did not differ significantly. There was no difference in prescribed vitamin D and elemental aluminum in phosphate binders. This study demonstrates that patients with dialysis encephalopathy had more rib fractures without more parathyroid or osteopenic bone disease than did the control subjects and suggests that the etiology of dialysis encephalopathy and osteomalacia is multifactorial.
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PMID:Dialysis encephalopathy and osteomalacic bone disease: a case-controlled study. 703 24

Ammonia metabolism in Reye syndrome was studied by quantitative analysis of the time course of hyperammonemia and the urinary excretion of ammonia, urea, and total nitrogen. These measures were then utilized to assess the effect of citrulline administration in 8 patients compared to results in 22 patients managed without citrulline. Two indices of the severity and duration of hyperammonemia correlated strongly with mortality: the half-time for decline of hyperammonemia and the area under the hyperammonemia curve (an index of the total burden of ammonia presented to the brain). These results suggest that the total amount of ammonia delivered to brain may be important to the pathogenesis of encephalopathy. Citrulline-treated patients had more severe disease at admission and greater abnormalities in indices of nitrogen and ammonia metabolism, though the latter did not reach significance. The urine ammonia/urea nitrogen excretion ratio, an index of the efficiency of ammonia conversion to urea, normalized more rapidly in the citrulline-treated group, evidence that citrulline may have improved urea cycle function. Overall mortality did not differ in the two groups. The deaths of 2 citrulline-treated patients in this small group were attributable to factors unrelated to treatment, however, so the possible effect of citrulline on mortality was not definitively tested. No indication was found that citrulline was harmful, nor that it increased ammonia levels.
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PMID:Ammonia metabolism in Reye syndrome and the effect of citrulline. 705 28


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