Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Utilizing a specific and sensitive radioimmunoassay, palsma and urine tyramine were measured in 14 consecutive patients with liver biopsy-proven Reye's syndrome. Plasma tyrosine was measured in 11 of these patients. The results revealed significant (P less than .003) elevation in plasma (3.4 +/- .52 ng/ml) (mean +/- SEM) and urine (1.00 +/- .26 mg/24 hr) tyramine as well as plasma tyrosine (204 +/- 52.5 mumole/liter) at the onset of the disease when compared to the levels of tyramine and tyrosine in a group of hospitalized patients without hepatic disorders. Furthermore, there was a positive correlation between plasma tyramine and days in coma (r = .86; P less than .001), and between plasma tyramine and tyrosine (r = 0.80; P less than .001). These data suggest that there is s substantial disturbance of tyrosine metabolism in Reye's syndrome and that the accumulation of this amino acid and its metabolite, tyramine, may contribute to the encephalopathy of this disease.
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PMID:Evidence for hypertyraminemia in Reye's syndrome. 45 May 66

beta-Oxidation of [1-14C]palmitic acid was examined in homogenates of astrocytes cultured from neonatal mouse brain. Under optimal reaction conditions (< or = 50 micrograms protein, 10 min at 37 degrees C), oxidation increased as a function of palmitate concentration (15 microM to 2 mM) and reached a maximum rate of 1.98 +/- 0.29 nmol/min/mg protein (mean +/- SEM) at 0.2 mM substrate. Eadie-Hofstee analysis of data from four experiments yielded apparent values for Vmax of 1.87 nmol/min/mg protein, and for Km, 35-40 microM. There were no dramatic changes in the oxidation rate in cells between 10 and 36 days in culture. During the 10-min assays, less than 0.05% of the radioactivity was converted to 14CO2 by the astrocytes; water-soluble products accounted for 1-2% of the total substrate added. Studies with KCN indicated that 60-70% of the total activity occurred in the mitochondria. We have been studying the structural and functional changes associated with the cerebral encephalopathy of Reye's syndrome (RS). Three-week-old astrocytes exposed to serum from RS children for the final 7 days of culture exhibited minor mitochondrial pleomorphism and had increased numbers of other intracellular organelles. Examination of the effects of agents implicated in RS indicated that oxidation of [1-14C]palmitate was not altered by Na+ salicylate (1-3 mM), but was inhibited by the industrial surfactant, Toximul MP-8 (> or = 10 micrograms/ml), 4-pentenoic acid (> or = 0.1 microM), or with 4 days' exposure to ammonia (10 nM). The latter treatment also resulted in an increase in protein synthesis, cell volume, and malondialdehyde formation. These results suggest that some of the "toxins" implicated in RS inhibit fatty-acid oxidation in the astrocytes and produce other lipid-related abnormalities that could be related to encephalopathy.
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PMID:Beta-oxidation of [1-14C]palmitic acid by mouse astrocytes in primary culture: effects of agents implicated in the encephalopathy of Reye's syndrome. 146 46

Elevated serum levels of gamma-aminobutyric acid (GABA), a potent inhibitory neurotransmitter, have recently been implicated in the pathogenesis of hepatic encephalopathy. In this study, serum GABA levels were measured in five children with severe Reye's syndrome, 10 children with acute viral hepatitis, and seven healthy volunteers. Serum GABA levels were highest in the five Reye's syndrome patients. The mean serum GABA level for the Reye's syndrome group (3.0 +/- 1.3 microM, mean +/- SEM) was significantly elevated as compared to the mean of the viral hepatitis group (0.72 +/- 0.07 microM, p less than 0.05) and the healthy volunteers (0.38 +/- 0.04 microM, p less than 0.05). These results provide preliminary evidence to suggest that elevated serum GABA levels may in part be responsible for the encephalopathic state observed in children with Reye's syndrome.
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PMID:Elevated serum gamma-aminobutyric acid levels in children with Reye's syndrome. 403 63