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Query: UMLS:C0036572 (seizures)
 80,221 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Inherited organic acidemias are a group of metabolic disorders currently being described and investigated as gas-liquid chromatography is applied to unexplained diseases of infancy and childhood. Common clinical presentations include attacks of ketoacidosis, unexplained metabolic acidosis, failure of normal development, seizures, and other neurologic abnormalities. Hyperglycinemia, hyperammonemia, and hypoglycemia are other laboratory findings frequently present. Diagnosis depends on examination of urine, and sometimes blood, by gas-liquid chromatography to measure concentrations of organic acids and organic acid derivatives. Prognosis in many cases is excellent if diagnosis is made promptly and the metabolic acidosis can be reversed. Recovery from neurologic deficits has frequently been seen. Long-term therapy is generally dependent on restricting precursors of the toxic organic acid which builds up as a consequence of the enzyme deficiency. If there is some enzyme activity retained or if alternate metabolic pathways exist, success with therapy is likely.
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PMID:Organic acidemias. 0 30

This study examines the possibility that changes of cerebral extracellular pH (PH e) or adenosine concentration may provide coupling mechanisms of a general nautre, adjusting cerebral blood flow (CBF) to metabolic demands. Although there is considerable indirect evidence that CBF varies inversely with pHe, results obtained during the last few years indicate that large increases in flow may occur in the absence of a fall in pHe. Thus, induction of hypoxia or epileptic seizures leads to maximal increase in CBF before pHe falls or even when there is initial alkalosis due to concomitant hypocapnia. Furthermore, CBF increases in hypoglycaemia and after administration of amphetamine, two conditions unassociated with tissue acidosis. The possibility that adenosine may be a coupling factor was examined in hypoxia and during epileptic seizures in rats. In both conditions a four- to fivefold increase in CBF occurs in spite of the fact that tissue adenosine concentrations remain at or below 1 mumolkg-u. It is concluded that adenosine accumulates first when there is a perturbation of cerebral energy state with a rise in AMP concentration. It seems unlikely that adenosine, formed by breakdown of AMP, acts as a general coupling factor.
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PMID:Coupling of cerebral metabolism and blood flow in epileptic seizures, hypoxia and hypoglycaemia. 2 37

Rats with different levels of blood glucose concentration were exposed to 10 min of complete brain ischemia achieved by compression of neck vessels by a pneumatic cuff. All normoglycemic rats survived the ischemic period and made the best clinical recovery. Hyperglycemic rats died within 12 h. Seizure activity was observed in all animals in this group. Three of eight hypoglycemic rats died between 3 and 16 days. The clinical recovery was less complete than in the control group. Thus, recovery from cerebral ischemia depends upon preischemic blood glucose concentration. Hyper- and hypoglycemia hamper the clinical recovery after transient cerebral ischemia.
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PMID:Clinical restitution following cerebral ischemia in hypo-, normo- and hyperglycemic rats. 3 Feb 50

Changes in plasma glucose, nonesterified fatty acids, insulin, glucagon, cortisol, growth hormone, and prolactin have been studied in baboons during the course of generalized epileptic seizures induced by intravenous bicuculline. Plasma glucose rose to a peak at 25 min but fell to hypoglycemic levels after 60 min of seizure activity. This hypoglycemia was accompanied by a marked elevation in plasma insulin. Plasma glucagon rose to a peak at 14 min, then returned to normal. Plasma growth hormone levels were elevated after 60 min of seizure activity. Plasma prolactin and cortisol levels also rose during the seizure. These changes result from sequential interaction of (1) autonomic activation at seizure onset, (2) spread of neuronal activity to the hypothalamus leading to the liberation of releasing factors, and (3) indirect physiologic consequences of seizure activity.
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PMID:Endocrine factors and glucose metabolism during prolonged seizures in baboons. 11 9

A Canadian Indian family is described in which three of the children were mentally retarded, and had seizures and other neurological abnormalities. They had chronic metabolic acidosis associated with elevated blood levels of lactate, pyruvate, and alanine. Two of the children excreted large amounts of pyruvic and alpha-ketoglutaric acids in the urine and had elevated plasma levels of glutamic acid and proline. Hypoglycemia occurred with fasting in two of the children. Treatment with pharmacological doses of thiamine, lipoic acid, biotin, riboflavin, and various dietary regimes was without effect. One child died at 3 1/2 months and another at 4 1/2 months; the third is still alive at 23 months of age. Enzyme assays revealed a low level of activity of both the pyruvate and alpha-ketoglutarate dehydrogenase complexes in cultured fibroblasts of one of the sibs. These patients appeared to have partial defects in the oxidation of pyruvate, as well as of alpha-ketoglutarate within the tricarboxylic acid cycle.
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PMID:Lactic acidosis in three sibs due to defects in both pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase complexes. 18 26

To evaluate the effects of substrate deficiency on cerebral function, metabolism, and blood flow during seizures, rats were injected intravenously with bicuculline (1.2 mg.kg-1) following a 24-hour period of starvation. During the course of seizures, blood glucose concentrations fell, and when they were reduced to below about 3 mumol.gm-1, cerebral function, metabolism, and blood flow altered. Changes in function involved the transition of an electroencephalographic pattern of bursts and suppression into one of frequent or sparse single spikes. Oxygen consumption, which initially increased at least twofold, fell toward normal or subnormal values in the single-spike period. Cortical blood flow was markedly reduced, and there was an attenuated response to carbon dioxide administration. Simultaneously, a small but clear fall was detected in the cerebral phosphorylation potential, and concentrations of glycolytic metabolites (including lactate) and citric acid cycle intermediates were reduced. Changes in amino acids and ammonia were somewhat similar to those observed in insulin-induced hypoglycemia, but since the amino acid pool did not fall, the experiments failed to give evidence that amino acids serve as oxidative substrates. The perturbation of cerebral energy state (and of levels of carbohydrate substrates and amino acids) was reversed by glucose administration; but since neither this procedure nor additional bicuculline injections could cause resumption of continuous seizure activity, the results suggest that cellular substrate depletion may have given rise to a sustained disturbance of synaptic transmission.
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PMID:Effects of bicuculline-induced seizures on cerebral metabolism and circulation of rats rendered hypoglycemic by starvation. 42 77

In order to determine the effects of acetate on signs and symptoms of hypoglycemic seizures, Swiss Webster albino mice were injected intraperitoneally with solutions of NaCl, NaHCO3, NH4Cl, Na-acetate, or NH4-acetate, followed by subcutaneous injection of 7 U of insulin/kg body wt. Administration of Na- or NH4-acetate delayed and reduced the incidence of hypoglycemic reactions. Reinjection with Na-acetate or repeated injections with NH4-acetate caused a return to normal behavior patterns for 60 and 75%, respectively, of the affected hypoglycemic experimental animals. Injections of control animals with NaHCO3 or NH4Cl showed that the results were not due to alkalosis or acidosis. Acetate administration significantly increased plasma acetate and citrate, but not glucose, lactate, beta-hydroxybutyrate, or acetoacetate concentrations. The results indicate that intraperitoneal administration of acetate directly acted to prevent signs of hypoglycemia from occurring and reversed its manifestations when they were present. The protective effect of acetate suggests that it may serve as a fuel for the brain.
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PMID:Effect of acetate on hypoglycemic seizures in mice. 48 41

The causes and short-term prognoses of neonatal convulsions in infants less than four weeks of age were studied in 77 full-term infants born in Stockholm in 1970--1976. In half of the infants (48%), hypoxia was considered to be the probable main etiology, while infection and metabolic disease including hypoglycemia and hypocalcemia were the next commonest cause, 12% for each condition. The etiology was unknown in 29% of the infants although 15 of those 22 included in this group had other additional diagnoses. The total mortality was 13%. At one year of age, 19 of the surviving 64 infants (30%) had severe psychomotor retardation. Of 11 infants with normal mental development at 12 months of age 6 had cerebral palsy and 5 epileptic seizures. Thirty-four (53%) of the infants still had no signs of sequelae. The poorest prognosis was found in the group with hypoxia as the main probable etiology. The incidence of neonatal convulsions was 1.5 per 1 000 full-ferm deliveries. In a similar study from Gothenburg which was performed 10 years earlier the incidence was 3.7 per 1 000. Corresponding figures for perinatal mortality rate were 13.5 and 23.8.
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PMID:Neonatal convulsions. Incidence and causes in the Stockholm area. 53 4

The role of physiological changes occurring during prolonged seizures in the causation of epileptic brain damage has been investigated experimentally in baboons and rats. Prolonged drug-induced myoclonic seizure activity is associated with initial arterial hypertension and subsequent hypotension, increased venous pressure, early hyperglycaemia and subsequent hypoglycaemia, variable arterial hypoxia and lactacidosis, and hyperpyrexia. Cerebral metabolic rate for oxygen and glucose is increased 2--3 fold throughout prolonged seizures provided the physiological status of the animal is well maintained. Ischaemic neuronal change is found after seizures lasting 1.5--7 hours, involving the small neurones of the third cortical lamina, Purkinje and basket cells in the cerebellum, and pyramidal neurons in the endfolium and Sommer sector of the hippocampus. Muscular paralysis and artificial ventilation minimise late physiological changes such as arterial hypotension and hyperpyrexia, and protect against cerebellar damage, but only slightly against neocortical and hippocampal damage. When arterial hypotension, hypoxia or hypoglycaemia lead to a reduction in the intensity of seizure discharge in paralysed, ventilated rats, there is also a reduction in hippocampal and neocortical damage. Factors intimately related to the intensity and duration of the neuronal discharge are responsible for neocortical and hippocampal lesions.
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PMID:Physiological changes during prolonged seizures and epileptic brain damage. 58 96

Reye's syndrome in infancy is not a well-defined entity and is infrequently diagnosed. Eight infants 6 months of age or younger had a prodromal viral illness followed by the rapid onset of lethargy, seizures, and coma, resulting in the diagnosis of Reye's syndrome. All had abnormal results of liver function tests including elevations of blood ammonia level. Three patients had pathological studies that confirmed fatty visceral infiltration. The data on these patients, as well as a review of the literature, indicate that the most prominent clinical findings in Reye's syndrome in infancy include marked respiratory abnormalities with tachypnea and apneic episodes; frequent occurrence of seizures in the early stages of the illness; and hypoglycemia in most cases. A strong socioeconomic bias was noted in these patients, with the infants coming primarily from lower socioeconomic, urban environments, while older children with Reye's syndrome have been observed to be predominantly middle-class and from suburban or rural areas.
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PMID:Reye's syndrome in infancy. 68 88


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