Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0085584 (encephalopathy)
 18,178 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Patients with chronic liver disease, yet without severe encephalopathy, were found to show evidence of increased brain utilization of glucose. The changes were abolished after an intravenous infusion of 15 g ornithine alpha oxoglutarate, given over a period of 15 minutes. The possible implications of these observations are discussed.
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PMID:Effect of ornithine alpha oxoglutarate on brain metabolism in patients with chronic liver disease. 23

Two subsequent phases of hepatogenic encephalopathy (HE), the metabolic and precomatous phase, were produced in rats by thioacetamide treatment. Plasma and brain levels of arginine and its metabolites in the arginine-glutamate pathway, and activities of 2 brain enzymes of this pathway: arginase (L-arginine amidohydrolase, EC3521) and ornithine amino-transferase (OAT, ornithine-oxo-acid aminotransferase, EC26113) were measured in these rats. Plasma arginine sharply decreased in the metabolic phase and rose above control level in the precomatous phase, whereas ornithine and glutamate increased and urea decreased in both phases. Brain amino acids levels remained unchanged throughout, confirming earlier report of their insensitivity to external manipulation. Both brain enzymes showed a similar stepwise increase in their activities up to 150% the control level. The results are indicative of increased involvement of arginine as a precursor of amino acid neurotransmitters glutamate and GABA, with possible implication for the course of HE.
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PMID:Arginine in thioacetamide-induced hepatogenic encephalopathy in rats: activation of enzymes of arginine metabolism to glutamate. 287 5

Young male ferrets developed hyperammonemia and encephalopathy shortly after eating a diet lacking in arginine. The dietary supplementation of arginine or intraperitoneal injection of ornithine prevented hyperammonemia and shortened the duration of encephalopathy. Therefore, young ferrets were assumed to be unable to meet their ornithine needs from sources other than arginine. Adult ferrets did not develop hyperammonemia and encephalopathy after eating arginine-free diet. Because young ferrets are also susceptible to human influenza infections, they were further tested as animal model of Reye's syndrome. Reye's syndrome is a serious childhood disorder that develops following influenza infections and is characterized in part by an encephalopathy, hyperammonemia and elevated serum transaminases. In young ferrets, concurrent administration of aspirin with human influenza inoculation and an arginine-free diet produced symptoms similar to those seen in humans with Reye's syndrome. The ferret model appears to be useful for studying the roles of various etiologic agents and their interactions in producing Reye's syndrome-like disorders. The ammonia metabolism in ferrets is reviewed and the ferret model for Reye's syndrome and its applications for the better understanding of this disorder in humans are discussed.
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PMID:Arginine deficiency, hyperammonemia and Reye's syndrome in ferrets. 299 54

Ornithine and arginine compounds were highly effective in preventing an increase in blood ammonia and in preventing or minimizing encephalopathy after acute subcoma, coma-inducing, or lethal doses of NH4+. Similar protection was seen after subacute loading with glycine. Ornithine ketoacid derivatives were no more effective than ornithine alone or ornithine glutamate. Ornithine appeared to be a little more effective than arginine, but the differences were slight. Aspartate and glutamate alone were ineffective. Carbamyl glutamate was much less effective than either ornithine glutamate or arginine glutamate. Orotic acid excretion was markedly increased in the presence of excess NH4+. This increment was eliminated with ornithine or arginine, although the reduction with arginine was unpredictably erratic. Aspartate increased the orotic acid excretion and the amount of urea formed. Sodium benzoate was borderline in its effect on the blood ammonia and on orotic acid excretion.
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PMID:Ammonia toxicity: comparative protective effect of various arginine and ornithine derivatives, aspartate, benzoate, and carbamyl glutamate. 350 33

Two-month-old, male ferrets were fasted for 16 h and fed a synthetic, arginine-free diet. Within 2-3 h after ingesting the diet, they developed hyperammonemia and encephalopathy. Ammonia levels in the serum, brain and cerebrospinal fluid were greatly elevated compared to those of ferrets fed the synthetic diet supplemented with arginine. Orotic acid and glucose levels in serum were also significantly elevated. Urinary orotic acid was significantly increased but citrate and creatinine level were unaltered. Adult (18-mo-old) ferrets did not develop hyperammonemia and encephalopathy after eating the arginine-free diet. Serum and urinary orotic acid levels were significantly elevated in the adult ferrets fed arginine-free diet. Hyperammonemia and encephalopathy were prevented in young ferrets by supplying dietary arginine and abbreviated by ornithine injections given during encephalopathy. These results suggest that young ferrets are unable to meet their ornithine needs from precursors other than arginine, whereas adult ferrets appear to be able to synthesize ornithine from sources other than dietary arginine. Intraperitoneal injection of sodium benzoate to young ferrets fed arginine-free diet failed to decrease serum ammonia levels.
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PMID:Effect of arginine-free diet on ammonia metabolism in young and adult ferrets. 395 2

The etiology of uremic encephalopathy remains largely unknown. In order to elucidate the role of amino acid changes in uremic encephalopathy, the free amino acids in serum and cerebral cortex were measured in the experimental uremic models. The rats weighing 200 g underwent bilateral ureteral ligation for 48 hours (acute uremia), while the other animals were kept for 4 months after unilateral nephrectomy followed by partial 2/3 nephrectomy of the remaining kidney (chronic uremia). They were confirmed to develop chemical changes compatible with uremia showing markedly elevated serum levels of BUN, creatinine and K+, and were compared with the sham-operated controls. The amino acid patterns, obtained from serum and cerebral cortex, were essentially identical in both acute and chronic uremia. In serum, aspartic acid, glycine and 3-methylhistidine were significantly elevated, and in addition citrulline, alpha-aminoadipic acid, cystine and gamma-aminobutyric acid specifically appeared in uremia. On the contrary, glutamic acid, leucine, lysine, tryptophan, tyrosine and valine were significantly reduced. Tyrosine/phenylalanine ratio, valine/glycine ratio, essential amino acids/non essential amino acids ratio were also apparently reduced in uremia. In cerebral cortex, aspartic acid, glutamine, glycine, histidine, ornithine, phenylalanine, phosphoethanolamine and taurine were significantly elevated, whereas 1-methylhistidine and 3-methylhistidine were specifically detected. Carnocine, glutamic acid and ornithine disclosed a significant reduction in uremia. The above complicated changes in cerebral cortex could not be explained simply by the enhanced permeability of the blood-brain barrier, or by the accelerated ammonia fixation. Therefore, it was suggested that the amino acid levels in cerebral cortex vary under the control of the sophisticated mechanism.
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PMID:[A comparative study of free amino acid levels in serum and cerebral cortex in uremic rat]. 650 56

The amino acid solution, Aminofusin hepar, was evaluated for treatment of hepatic encephalopathy and for parenteral nutrition of patients with liver cirrhosis in correlation to changes in amino acid levels. In contrast to amino acid solutions used for the parenteral nutrition of patients without liver disease, this solution contains an increased proportion of branch chained amino acids and of arginine and ornithine, and a reduced proportion of phenylalanine, methionine, glycine and threonine. The changes in the plasma amino acid levels after infusion of this solution were measured in 4 cirrhotics. The concentration of leucine, isoleucine, valine, ornithine and arginine increased markedly, whereas phenylalanine, methionine, tyrosine, glycine and threonine decreased. The ammonia level in venous blood increased slightly. 4 cirrhotics with encephalopathy were treated for 7 days. In 3 of them the neuropsychiatric symptoms were completely reversed, whereas in the remaining 1 no clinical improvement was achieved in spite of normalization of the plasma aminogramm. In this patient a constant rise of blood ammonia was noted. The indications for special amino acid solutions in liver diseases are discussed.
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PMID:[Parenteral feeding of patients with liver cirrhosis with hepatic encephalopathy]. 677 52

The clinical features and the computed tomographic appearances of the brain in seven children with ornithine carbamoyl transferase deficiency are described. Episodic vomiting and drowsiness, acute encephalopathy, failure to thrive and developmental retardation were common, but focal neurological symptoms and signs were also observed. The CT appearances were non-specific with generalised or focal changes. They were related to the severity, the duration and the age of onset of the hyperammonaemia. Since the CT changes may suggest conditions other than metabolic disease, the emergency investigation of a child with an encephalopathy should include the estimation of plasma ammonium and, if elevated, the appropriate investigations to establish the cause.
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PMID:Neurological features and computed tomography of the brain in children with ornithine carbamoyl transferase deficiency. 684 97

The levels of free amino acids in the cerebral cortex of acute and chronic uremic rats were examined. Amino acids significantly elevated were aspartate, glutamine, glycine, histidine, ornithine, phenylalanine, phosphoethanolamine and taurine, whereas 1-methyl histidine and 3-methyl histidine were specifically detected in uremic rats. Glutamate, arginine and carnosine disclosed a significant reduction. There was no change in the concentrations of gamma-aminobutyrate and alanine. The above findings were essentially identical in both acute and chronic uremia. It was conjectured that these changes of amino acid levels in the brain might participate in the progress of uremic encephalopathy.
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PMID:Free amino acid changes in the cerebral cortex of experimental uremic rat. 685 32

In eight patients with chronic portal-systemic encephalopathy who were symptomatic despite protein restriction and lactulose, a double-blind crossover comparison was conducted of branched-chain amino acids (68 mmol/d) versus ornithine salts of branched-chain ketoacids (34 mmol/d), both mixtures being administered orally for 7 to 10 days, after control periods, during a single hospitalization. Ornithine salts of branched-chain ketoacids markedly improved electroencephalographic abnormalities and clinical grade of encephalopathy; branched-chain amino acids had significantly lesser effects, which were of borderline statistical significance. To ascertain whether ornithine or branched-chain ketoacids were responsible for the improvement observed, we administered to six patients calcium salts of branched-chain ketoacids (34 mmol/d) after control periods; only slight improvement was seen.. Four patients received a daily dose of ornithine alpha-ketoglutarate containing the same quantity of ornithine; one did not change and three deteriorated rapidly. We conclude that the combination of ornithine and branched-chain ketoacids improves chronic portal-systemic encephalopathy more than its components given separately and more than branched-chain amino acids at twice the molar dose.
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PMID:The use of ornithine salts of branched-chain ketoacids in portal-systemic encephalopathy. 700 71


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