Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0035400 (Reye's syndrome)
 879 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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

Reye's syndrome is an acute hepatopathy and encephalopathy affecting children during the convalescent period of a viral infection, frequently influenza B. The role of influenza B in the pathogenesis of Reye's syndrome is unknown. To investigate this relationship, an in vitro system was designed to examine the interaction of influenza B virus with a cell line of human hepatocytes (HepG2) which retains many specific hepatic synthetic characteristics. HepG2 was capable of supporting a productive infection by influenza B, although greater virus inputs were required than in fully permissive Madin-Darby canine kidney cells. Because of the recent association of Reye's syndrome with aspirin use, the kinetics of influenza B growth were studied in the presence of acetylsalicylic acid (25 and 100 micrograms/ml) and were not found to be altered. Protein synthesis by HepG2 cells was decreased by 80% in influenza B-infected cells when compared to uninfected controls. Acetylsalicylic acid, 100 micrograms/ml, did not affect the rate of 35S-methionine incorporation by infected or uninfected HepG2 cells. The rates of synthesis of specific proteins (albumin, transferrin, and apoprotein B) by HepG2 cells were determined by immunoprecipitation of 35S-methionine labeled cell lysates. After 12 h of infection, synthesis of all three plasma proteins was decreased by 40-60%. These studies describe a useful system for delineation of mechanisms by which influenza B virus interacts with host hepatocytes and the host-cell protein synthetic machinery. The studies could be pertinent to the pathogenesis of Reye's syndrome.
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PMID:Protein synthesis by HepG2 cells infected with influenza B virus. 283 18

Reye syndrome, a reversible metabolic encephalopathy and hepatopathy, offers a unique opportunity to investigate the pharmacologic mechanisms by which a toxic-metabolic insult to mitochondria is translated into neurochemical and neurologic dysfunction. Similarity of some clinical and metabolic abnormalities between certain inborn errors of organic acid, ammonia, and carbohydrate metabolism and Reye syndrome suggests a common pathophysiologic mechanism at some level. The primary metabolic aberration in Reye syndrome is unknown. Viral, drug, and toxic precipitants in a conductive host alter glial and neuronal function, possibly by direct toxic effects or by altered transmitter metabolism and signal transduction. These events translate into a rather stereotyped progression of the clinical syndrome. Increased ICP, which is a life-threatening epiphenomenon, is the focus of conventional therapy. Investigational treatments, still in preliminary stages, are aimed at early correction of instigating metabolic abnormalities or correction of their consequences on central neurotransmission. Our fragmentary knowledge of neurotransmitter abnormalities in this disorder, which have suggested disparate interpretations, does not allow a cohesive pharmacologic theory of Reye syndrome. The greatest difficulties in interpretation of possible central mechanisms from existing data, which derive largely from peripheral tissues, is in the differentiation of primary from compensatory changes. The unitarian notion that a single pharmacologic disturbance is the source of the encephalopathy is perhaps too simplistic. It is hoped that future studies of disorders such as Reye syndrome will elucidate the intricate relationships between biochemical pathways and neurotransmitter metabolism.
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PMID:Pharmacology of Reye syndrome. 284 66

Transient severe hyperammonaemia developed in the absence of serious liver dysfunction in three patients being treated for acute leukaemia. The onset of the biochemical disturbance was abrupt and led rapidly to acute encephalopathy, fatal in two cases. In the third patient, prompt initiation of aggressive haemodialysis and intravenous sodium benzoate and sodium phenylacetate infusion successfully controlled plasma ammonium levels until they spontaneously resolved. The cause of the disorder remains to be determined, but urinary nitrogen partition studies suggest temporary impairment of ureagenesis in a catabolic setting as a major pathophysiological feature of this disorder. The absence of liver disease, the normal mitochondrial ultrastructure seen in two cases, and the plasma aminoacid profiles observed serve to distinguish this disorder from others such as Reye's syndrome.
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PMID:Transient idiopathic hyperammonaemia in adults. 286 37

A case of cerebral oedema developed during an apparently common attempted suicide with valpromide is reported. The most conspicuous biochemical abnormality was hyperammonaemia. The oedema proved refractory to the standard medical treatment of intracranial hypertension, and decompressive craniectomy was performed with only minor sequelae. The cerebral oedema cum hyperammonaemia syndrome led to the discovery, in this hitherto asymptomatic adult subject, of a 50 per cent deficiency in type a carbamyl phosphate synthetase liver activity. By completing such a deficiency, valproate may produce an extremely serious syndrome resembling the neonatal encephalopathy due to complete enzyme deficiencies in the urea cycle. All valpromide or valproate intoxications probably are cerebral oedemas with hyperammonaemia akin ti Reye's syndrome. All accidents of this type occurring during treatment or poisoning with valproate should be investigated for urea cycle enzyme abnormalities.
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PMID:[Cerebral edema with hyperammonemia in valpromide poisoning. Manifestation in an adult, of a partial deficit in type I carbamylphosphate synthetase]. 297 63

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

Between July 1983 and February 1984, eight children with adenovirus Type 3 infection, proven by virus isolation from sputum, stool or nasopharyngeal swabs and a fourfold increase in complement fixation antibody titers against the virus, were treated in our department. All eight patients had fever lasting at least 7 days, hepatomegaly, diffuse pulmonary infiltrates and abnormal liver function tests. Seven of the patients exhibited dyspnea and pulmonary wheezing. Six of the patients developed changes in state of consciousness, and three had repeated convulsions. EEG patterns in three of the patients were compatible with encephalopathy. Other clinical manifestations included: follicular tonsillitis in two patients, diarrhea in two, pneumothorax in one, and shock with disseminated intravascular coagulation in one. The spectrum of adenovirus Type 3 infection reported here has been described previously only in the viral hemorrhagic fevers. This adenovirus Type 3 infection shares the potential for disseminated disease that has been described previously for Type 7, simulating Reye's syndrome.
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PMID:Adenovirus type 3 infection with systemic manifestation in apparently normal children. 302 30

Reye's syndrome (RS) has been defined by the CDC as an acute non-inflammatory encephalopathy and hepatopathy, with no reasonable explanation for the cerebral and hepatic abnormalities. The diagnosis of RS is made by a constellation of clinical and laboratory features, none of which are pathognomonic. The demonstration of a fatty infiltration on liver biopsy is not really specific. On the other hand, the mitochondrial ultrastructural abnormalities appear to be characteristic of RS. Cerebral edema with intracranial hypertension represents the most immediate threat to life, the cause of the encephalopathy being unknown. The treatment of RS consists in perfusion of hypertonic glucose solution and management of intracranial hypertension. Grade I RS should be recognized early and treated with intravenous glucose. A number of metabolic disorders may yield a clinical picture resembling RS. These include disturbances of organic acid metabolism, urea cycle defects, and disorders of carbohydrate metabolism. The pathogenesis of RS is a mitochondrial insult induced by different viruses, drugs, exogenous toxins, and genetic factors. In the USA, pilot studies showed that a majority of RS cases may be attributable to salicylate use. In France, RS remains unfrequent although no precise epidemiological data are available. An epidemiological study appears therefore necessary for a better understanding of this mysterious syndrome. There is a need for a biological marker of the mitochondrial injury.
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PMID:[Reye's syndrome. A current entity which remains enigmatic]. 305 99

Pertussis vaccine was originally accused of provoking a short latency explosive encephalopathy with serious mental and physical consequences. Reports of recurrence of encephalopathy, worse after each dose, strengthened the notion of causality. Anecdotal associations can be no more than hypothesis-generating. With no distinctive clinical or pathological neurology, a major epidemiological study was necessary to answer the question "Does whooping cough vaccine cause brain damage in children"? The British national Childhood Encephalopathy Study (NCES) seemed to indicate that very rarely the answer was yes. Unfortunately the NCES confused disorders which might be notified as "encephalopathy" with actual brain damaging events, imaging a continuum of injury. Close scrutiny of the individual cases, as was possible during the recent test case in the High Court of London, shows that all the temporally associated cases with permanent sequelae had either viral encephalitis or Reye's syndrome. No cases were unexplained. There was an apparent excess of febrile convulsions in the first 24 hours, but all these children were normal at follow-up. The short latency explosive encephalopathy with adverse outcome predicted by the earlier case series did not occur. The NCES gives no support to the idea that pertussis vaccine damages children's brains. Contra-indications to DTP should be the same as to DT.
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PMID:A neurologist looks at neurological disease temporally related to DTP immunization. 307 4

Valproic acid is known to cause an increase in blood ammonia levels in humans at the usual clinical dose. In most patients, this increase is small and asymptomatic, but in some patients the increase is larger and is associated with encephalopathy. In this study, valproate also caused a small increase in blood ammonia level (from 50 to 83 mumol/l) in Wistar rats. Salicylate potentiated this increase in blood ammonia (greater than 210 mumol/l) when coadministered with valproate at a dose of salicylate which did not cause a significant increase when given alone. Other nonsteroidal anti-inflammatory drugs tested (ibuprofen and naproxen) did not potentiate valproate-induced hyperammonemia, and paracetamol actually appeared to decrease ammonia levels. The degree of hyperammonemia was dependent upon diet, and fasting decreased the level of hyperammonemia. In order to determine what component of the diet was responsible for this effect, protein, fat and carbohydrate were given by gavage, individually and also a mixture of the three. Only the mixture was able to increase the degree of hyperammonemia, even though the number of calories in the mixture and in each nutrient given individually was approximately the same. 2,4-Dinitrophenol, which like salicylate uncouples oxidative phosphorylation, potentiated valproate-induced hyperammonemia at a much lower dose than salicylate. Whether salicylate can potentiate hyperammonemia and lead to encephalopathy in some patients and therefore represents one of the risk factors for observed cases of valproate toxicity remains to be determined. Potentiation of hyperammonemia by salicylates is also consistent with the apparent association between salicylates and Reye's syndrome which is also characterized by hyperammonemia.
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PMID:Salicylate potentiates valproate-induced hyperammonemia in the rat. 311 9


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