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

Propionic acidemia occasionally produces a toxic encephalopathy resembling Reye's syndrome, indicating disruption of mitochondrial metabolism. Liver mitochondria respiratory control ratios were reduced 46% by 5 mM propionate; inhibition correlated with matrix propionyl-CoA levels. L-Malate prevented the toxic effect of propionate and reduced the propionyl-CoA matrix concentration by 62%. The beneficial effect of L-malate is apparently due to stimulation of succinate efflux because the effect is blocked by benzylmalonate, an inhibitor of the dicarboxylate carrier. Matrix concentration of label from [1-14C]propionate was not affected by L-malate and/or benzylmalonate. L-Malate may be useful in the treatment of patients with propionic acidemia.
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PMID:The effect of malate on propionate mitochondrial toxicity. 178 9

Propionic acidemia occasionally produces a toxic encephalopathy resembling Reye syndrome, indicating disruption of mitochondrial metabolism. Understanding the mitochondrial effect of propionate might clarify the pathophysiology. Liver mitochondria are inhibited by propionate (5 mM) while muscle mitochondria are not. Preincubation is required to inhibit liver mitochondria, suggesting that propionate is metabolized to propionyl CoA. Liver and skeletal muscle mitochondria incubated with [1-14C]propionate contain similar quantities of matrix isotope and release comparable [14C]CO2. However, only liver mitochondria accumulated significant propionyl CoA, which was largely (68%) synthesized from propionate. Carnitine reduced the level of liver matrix propionyl CoA. Inhibition of respiratory control ratios by propionate correlated with propionyl CoA levels. These results support the hypothesis that acyl CoA esters are toxic and that carnitine exerts its protective effect by converting acyl CoA esters to acylcarnitine esters.
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PMID:Propionate mitochondrial toxicity in liver and skeletal muscle: acyl CoA levels. 188 30

Carnitine deficiency can be defined as a decrease of intracellular carnitine, leading to an accumulation of acyl-CoA esters and an inhibition of acyl-transport via the mitochondrial inner membrane. This may cause disease by the following processes. A. Inhibition of the mitochondrial oxidation of long-chain fatty acids during fasting causes heart or liver failure. The latter may cause encephalopathy by hypoketonaemia, hypoglycaemia and hyperammonaemia. B. Increased acyl-CoA esters inhibit many enzymes and carriers. Long-chain acyl-CoA affects mitochondrial oxidative phosphorylation at the adenine nucleotide carrier, and also inhibits other mitochondrial enzymes such as glutamate dehydrogenase, carnitine acetyltransferase and NAD(P) transhydrogenase. C. Accumulation of triacylglycerols in organs increases stress susceptibility by an exaggerated response to hormonal stimuli. D. Decreased mitochondrial acetyl-export lowers acetylcholine synthesis in the nervous system. Primary carnitine deficiency can be defined as a genetic defect in the transport or biosynthesis of carnitine. Until now only defects at the level of carnitine transport have been discovered. The most severe form of primary carnitine deficiency is the consequence of a lesion of the carnitine transport protein in the brush border membrane of the renal tubules. This defect causes cardiomyopathy or hepatic encephalopathy usually in combination with skeletal myopathy. In a patient with cardiomyopathy and without myopathy, we found that carnitine transport at the level of the small intestinal epithelial brush border was also inhibited. The patient was cured by carnitine supplementation. Muscle carnitine increased, but remained too low. This suggests that carnitine transport in muscle is also inhibited. Carnitine transport in fibroblasts was normal, which disagrees with literature reports for similar patients.
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PMID:Primary carnitine deficiency. 219 96

Calcium hopantenate (HOPA) has been widely used as an activator of cerebral metabolism in Japan. However, several cases of acute encephalopathy during HOPA administration were recently reported, which were characterized by marked metabolic acidosis and hypoglycemia. The encephalopathy in these patients was named Reye-like syndrome because of the similarity to Reye's syndrome in children. The purposes of this presentation are to report on 5 patients with acute encephalopathy developing during HOPA administration, to summarize their symptoms and clinical courses, and to discuss the pathogenesis of metabolic acidosis and hypoglycemia. Initial characteristics of the clinical course in all patients were loss of appetite, nausea and vomiting, followed by unconsciousness. Laboratory examinations revealed marked metabolic acidosis, severe hypoglycemia, hyperlactacidemia, leukocytosis, ketonuria, and increased Ht and BUN. A few days after development of the initial symptoms, mild renal and liver dysfunction, and elevation of serum amylase were observed in all patients. Hyperlactacidemia was present in 4 in the initial period. Blood concentration of HOPA was 2.131 micrograms/ml in patient 1 (8-10 hours after final administration), and 10.7 micrograms/ml in patient 5 (24 hours after final administration). These values are extremely high, because usually HOPA concentration is almost negligible 7 hours after the drug is taken. As the pathogenesis of acute encephalopathy due to HOPA administration, the failure of fatty acid beta-oxidation has been proposed by some investigators. However, the serum concentrations of CoA, pantothenic acid and carnitine during the initial stage were not reduced in our patients. Furthermore, it is very difficult to explain the severe hypoglycemia in terms of the beta-oxidation theory.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Metabolic acidosis and hypoglycemia during calcium hopantenate administration--report on 5 patients]. 258 87

An unusual clinical course of a patient with biotinidase deficiency, causing Leigh syndrome, is reported. Laryngeal stridor was the major presenting symptom followed by progressive neurologic deterioration and death at the age of 21.5 mo. Absence of skin and hair abnormalities as well as of organic aciduria delayed the correct diagnosis. Necropsy revealed subacute necrotizing encephalopathy (Leigh syndrome). Carboxylase activities (propionyl CoA carboxylase, 3-methylcrotonyl-CoA carboxylase, pyruvate carboxylase) measured in lymphocytes 1 day before death were decreased to 10% of normal values. Propionyl-CoA carboxylase was shown to be the only stable carboxylase in human postmortem tissue; in our patient it was moderately decreased in postmortem liver (29% of control) and kidney (42%), but severely decreased in brain (3%). These findings might explain the severity of neurological symptoms in the absence of marked organic aciduria. They indicate that in biotinidase deficiency the CNS may become biotin depleted earlier and more severely than other organs. Biotinidase deficiency should be included in the differential diagnosis of Leigh syndrome and of unexplained respiratory problems.
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PMID:Biotinidase deficiency: a cause of subacute necrotizing encephalomyelopathy (Leigh syndrome). Report of a case with lethal outcome. 258 27

Recently a number of defects of fatty acid transport and beta-oxidation have been described. Primary carnitine deficiency presents itself as muscle carnitine deficiency, systemic carnitine deficiency or a cardiomyopathic subtype. Another abnormality of fatty acid transport is due to inner carnitine palmitoyl transferase deficiency, usually associated with a myoglobinuric phenotype. Long chain, medium and short chain acyl-CoA-dehydrogenase defects are usually associated to Reye's syndrome, encephalopathy, organic aciduria and secondary carnitine deficiency.
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PMID:[Alterations of mitochondria in metabolic diseases. Carnitine deficiency, carnitine palmitoyltransferase deficiency and beta oxidation]. 260 79

Reye's Syndrome (RS) is characterized by encephalopathy, fatty degeneration of viscera and high levels of free fatty acids which are implicated in cellular toxicity. We have examined the effects of octanoic acid (C8:0), palmitic acid (C16:0) and oleic acid (C18:1) on rat liver mitochondrial swelling by spectroscopic and microscopic techniques. Of the fatty acids tested oleic acid had a greater effect than palmitic acid while octanoic acid had no effect. Acyl-CoA derivatives produced greater mitochondrial swelling than either acyl-carnitine or free fatty acids. However, identical amounts of palmitoyl-CoA and oleoyl-CoA were required to produce the same degree of swelling. Addition of carnitine (2mM) to oleoyl-CoA reduced the mitochondrial swelling significantly thus suggesting that the toxicity of the fatty acids may be reduced by conversion to their carnitine derivatives. Twice the concentration of oleoyl-carnitine was required to produce half the maximum swelling as compared to oleoyl-CoA. Ultrastructural profiles of mitochondria treated with oleic acid, oleoyl-CoA and oleoyl-carnitine demonstrated greater swelling with oleoyl-CoA than with oleic acid or oleoyl-carnitine. These results suggest that carnitine may protect the mitochondria from damage by the fatty acids and their acyl-CoA derivatives in Reye's Syndrome.
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PMID:Effect of fatty acids and their derivatives on mitochondrial structures. 277 51

A boy suffering from recurrent episodes of acute encephalopathy and hepatic steatosis died at 40 months of age. The symptoms started when he was 13 months old and he appeared completely normal in the intervals. Pertinent biologic findings were as follows: slight labile hypoglycemia and hyperammonemia having no direct correlation with neurologic derangement, no elevation of ammonia levels in loading tests, complete failure to generate ketones and the absence of organic aciduria during a fast, normal plasma carnitine levels and normal activity of long and medium chain acyl-CoA-dehydrogenase in skin fibroblasts. Pertinent autopsy findings were marked steatosis of liver and renal tubular cells with many foamy histiocytes in bone marrow. An error in metabolic pathways, particularly a derangement in lipid metabolism, was considered.
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PMID:[Acute encephalopathy and recurrent hepatic steatosis with normal long and medium chain fatty acyl-CoA-dehydrogenase activity]. 361 69

We have previously reported that chronic valproate administration reduced ketonemia in suckling mice and fasting epileptic children. The present study demonstrates that even a single dose of valproate in the therapeutic range for man caused a prolonged reduction of plasma beta-hydroxybutyrate levels in normal infant mice; the plasma glucose concentration was also significantly lowered. In the livers of these animals, there were extraordinary decreases in levels of free coenzyme A, acetyl CoA and free carnitine. Concomitantly concentrations of acid-soluble fatty acid (short-chain, non-acetyl) coenzyme A esters and of acid-insoluble (long-chain) fatty acid carnitine esters increased. There was evidence for inhibition of the metabolic flux through the Krebs citric acid cycle at those enzyme reactions which require coenzyme A. While valproate doubled liver alanine levels, concentrations of liver aspartate, glutamate and glutamine were reduced. All of the valproate-induced metabolite changes can be explained by the decrease of coenzyme A due to the accumulation of acid-soluble (non-acetyl) coenzyme A esters (presumably valproyl CoA and further metabolites). Decreased coenzyme A would limit the activities of one or more enzymes in the pathway of fatty acid oxidation and the Krebs citric acid cycle. Secondary decreases in acetyl CoA would limit both ketogenesis and gluconeogenesis. Decreased levels of selected hepatic amino acids could reflect their use as alternative fuels. The effect of clinical doses of valproate in infant mice may relate to the valproate-associated syndrome of hepatic failure and Reye-like encephalopathy in some infants and children and suggest a simple screen for those who may be at particular risk.
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PMID:A single therapeutic dose of valproate affects liver carbohydrate, fat, adenylate, amino acid, coenzyme A, and carnitine metabolism in infant mice: possible clinical significance. 392 91

A 9-year-old girl was referred to our hospital after recurrent episodes of hypoglycemia, altered consciousness and persistent vomiting without acetonemia or myopathic symptoms. Other pertinent laboratory data included elevated BUN, hyperammonemia and very low levels of triglycerides with elevated free fatty acids. The patient was born from unaffected but related parents (second cousins) and the illness was previously diagnosed as Reye encephalopathy. Recurrence of similar attacks suggested an underlying metabolic disorder. Several syndromes of impaired FFA beta oxidation were taken into account and discarded successively after laboratory investigations: systemic carnitine deficiency, Medium and Long Chain Acyl-CoA Dehydrogenase deficiency and Multiple Acyl CoA Dehydrogenation deficiency (Glutaric aciduria, Ethylmalonic-adipic aciduria and riboflavin-responsive multiple acyl CoA dehydrogenation deficiency). Urinary and hematic gas-chromatography and Mass-Spectrometry show no abnormality in Medium Chain fatty acids and in C6-C10 dicarboxylic acids. Carnitine plasma concentrations (both total and free) were above normal levels while in urine acetyl carnitine was low in respect to longer acyclic radicals. Among metabolic defects located at the level of hepatic fatty acid oxidation, only Carnitine Transferase deficiency can explain this peculiar mosaic of data (precursors of the blocked reaction are elevated in blood whereas lack of the metabolites derived uniquely from this reaction explains all the clinical manifestations).
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PMID:[Non-ketotic hypoglycemia caused by carnitine palmitoyl transferase 1 deficiency]. 848 29


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