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

We studied the effects of transcranial magnetic stimulation (TMS) applied in trains of 8- to 25-Hz stimuli on electroencephalographic epileptiform activity on eight patients being evaluated for epilepsy surgery. We performed the stimulation with a round water-cooled stimulation coil held flat on the scalp and centered over different positions of the International 10-20 System. We were unable to trigger seizures or induce epileptiform discharges arising from the epileptic focus in any of the eight patients with any of the stimulation protocols. However, we induced a partial motor seizure from the contralateral hemisphere to the exclusive temporal focus in the only patient stimulated with 100% maximal intensity. Precautions have to be taken when applying rapid TMS to patients because of the risk of seizure induction. Our results do not support the view that TMS specifically activates the epileptic foci.
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PMID:Transcranial magnetic stimulation in patients with epilepsy. 162 Mar 63

Pulmonary function was studied in ten preeclamptic women in labor (mean gestational age 38.1 +/- 0.9 weeks measured from the last menstrual period) receiving continuous intravenous (IV) infusions of magnesium sulfate. Baseline maximal inspiratory pressure, maximal expiratory pressure, functional vital capacity, and forced expiratory volume at 1 second were measured immediately before a 6-g IV loading dose of magnesium sulfate and 2 hours after the initiation of a continuous 2-g/hour infusion of magnesium sulfate. Serum magnesium levels were measured at the same time pulmonary function tests were performed. All values are reported as the mean +/- standard deviation. The maximal inspiratory pressure, an indicator of generalized respiratory muscle weakness, decreased from a baseline value of 26.2 +/- 7.7 to 19.4 +/- 6.3 cm H2O (P less than .05). The maximal expiratory pressure, an indicator of expiratory muscle strength, decreased from a baseline value of 30.6 +/- 9.2 to 25.2 +/- 7.1 cm H2O (P less than .005). The functional vital capacity decreased from a baseline value of 3.37 +/- 0.49 to 3.19 +/- 0.73 L, and the forced expiratory volume at 1 second decreased from a baseline value of 2.61 +/- 0.58 to 2.36 +/- 0.68 L at 2 hours (P less than .05). The mean serum magnesium level was 1.7 +/- 0.2 mg/dL before the administration of the IV loading dose and 4.51 +/- 0.67 mg/dL 2 hours after initiation of the continuous infusion. Our results demonstrate a significant decrease in pulmonary function tests in term preeclamptic patients receiving magnesium sulfate for seizure prophylaxis.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Pulmonary function of preeclamptic women receiving intravenous magnesium sulfate seizure prophylaxis. 206 69

Carbamazepine (Tegretol) is widely used therapeutically as an anticonvulsant. Based on an hypothesis that links electrical kindling in the limbic system (leading to seizures) to reverse tolerance or sensitivity to cocaine's effects, carbamazepine is being tested as a treatment for human cocaine users. The purpose of this experiment was to examine the effects of carbamazepine on intravenous cocaine self-administration in rats. Rats self-administered intravenously delivered cocaine (0.2 mg/kg) under a fixed-ratio 4 schedule. When cocaine injections reached stable levels, carbamazepine was mixed with the rats' food for 8 days. Three doses of carbamazepine were tested (80, 120, and 160 mg/kg) in different groups of 5 rats each. The rats were later separated into groups with a high (greater than 750 infusions) and a low (500-750 infusions) cocaine baseline. Two control groups of 5 rats each received carbamazepine treatments (120 or 160 mg/kg) and self-administered an orally delivered solution of glucose and saccharin (G + S). At the highest carbamazepine dose in the high cocaine baseline group, carbamazepine reduced cocaine infusions by at least 50 percent and food intake by approximately 25 percent during the 8 days of treatment. Cocaine infusions returned to baseline within 24 hr after the regular diet was restored. Carbamazepine had a minimal effect in groups of rats with lower cocaine baselines. Responding reinforced by the G + S solution was reduced by both the 120 and 160 mg/kg carbamazepine doses. Water intake was not systematically affected by the addition of carbamazepine to the food; however, activity measures were significantly lower in some groups at the higher carbamazepine doses.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of carbamazepine on self-administration of intravenously delivered cocaine in rats. 208 94

Salivary levels of phenytoin, phenobarbitone, carbamazepine and carbamazepine-epoxide correlate with the simultaneous plasma water levels of these substances, after correcting for the effects of pH differences between saliva and plasma in the case of phenobarbitone. Saliva is easy and painless to collect, and salivary levels of the drugs are conveniently measured. Frequent (often daily) monitoring of pre-dose morning anticonvulsant drug concentrations in saliva over periods of weeks or months in 3 groups of epileptic subjects showed that (i) in some but not all poorly controlled epileptic patients seizures tended to occur on days when salivary anticonvulsant levels were lower than on non-seizure days, (ii) in such subjects it was possible to estimate an anticipated optimal drug concentration and dose to minimize seizure activity from the plot of seizure frequency against drug concentrations, (iii) in women with 'catamenial' epilepsy, salivary anticonvulsant levels were lower on perimenstrual days than at mid-cycle in half of the subjects studied, and (iv) in pregnant epileptic women the time course of the change in drug levels relative to dose could be followed more closely throughout pregnancy and the post-natal period than was practicable when using blood level measurements. Frequent measurement of salivary anticonvulsant concentrations appears a promising and inexpensive adjunct to the investigation and management of certain problem areas in epilepsy.
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PMID:Possible roles for frequent salivary antiepileptic drug monitoring in the management of epilepsy. 211 29

The anticonvulsant effects of two doses of clonazepam (CZP, Rivotril Roche, 0.1 and 1 mg/kg i.p.) were studied on model motor seizures induced by strychnine, bicuculline, 3-mercaptopropionic acid and metrazol in male laboratory rats (Wistar strain). In the first part the effects of different doses of the convulsants were investigated and for interaction with CZP doses were chosen after which more than 70% of the animals displayed generalized tonic-clonic convulsions (a grand mal seizure). Strychnine induced this type of seizure only: two doses (2 and 3 mg/kg s.c.) were used. CZP reduced the incidence of convulsions only after the larger dose, but plain solvent (propylene glycol, ethanol, water) was equally effective. The other substances first induced a seizure of minimal (mainly clonic) convulsions and only later a grand mal seizure. CZP was highly effective against bicuculline (3 mg/kg s.c.) and metrazol (100 mg/kg s.c.), but was less so against 3-mercaptopropionic acid. The effect on grand mal seizures was more pronounced in every case than on minimal seizures. The decisive role in the anticonvulsant effect of CZP is played by the mechanisms by which the convulsants induce epileptic manifestations. CZP is most effective against substances acting on the supramolecular complex GABA receptor (benzodiazepine receptor) chloride ionophore (bicuculline and probably metrazol).
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PMID:Anticonvulsant effects of clonazepam on chemically induced convulsions. 215 Sep 91

Ivermectin, a potent, effective anthelmintic, is easy to administer, has a broad spectrum of action and a wide safety margin. However, no testing has been done in hosts genetically selected for seizure susceptibility which may be more sensitive to the effects of ivermectin than other animals. This was done in the present experiments with seizure prone and seizure resistant mice infested with Syphacia obvelata (pinworm). These subjects were treated daily with oral ivermectin in their drinking water every other week for six weeks, for a total of 21 days. The treatment cleared the mice of the pinworm infestation, but did not alter the seizure susceptibility or binding parameters of [3H]flunitrazepam in either of the selected lines.
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PMID:Effect of chronic ivermectin treatment on GABA receptor function in ethanol withdrawal-seizure prone and resistant mice. 215 65

The 5-HT3 receptor antagonist BRL 43694 was administered in drinking fluid to Mongolian gerbils, previously selected for their propensity to exhibit seizures on mild stimulation, for 11 days at doses of 1.5 micrograms/kg, 150 micrograms/kg and 1 mg/kg daily, while controls received tap water. Effects upon behaviour during encounters under white light with an untreated resident gerbil were assessed using ethological procedures. Effects upon seizure susceptibility and severity were also examined. All doses of BRL 43694 significantly increased the time spent by gerbils in the social activity "attend", and acts of social investigation involving physical contact between animals were significantly increased only by the highest dose of 1 mg/kg, as was occurrence of the specific element, "groom". The duration of flight was increased in gerbils receiving the drugs at 1.5 micrograms/kg. The treatment had no effect upon seizure susceptibility or severity. It is suggested that BRL 43694 increases the sensitivity of gerbils to their social environment. At the lower dose this was seen as an increase in flight, at all doses it was associated with increase of the social activity "attend" and at the high dose it was manifested as an increase in active social interaction. Further investigations are required to assess the relevance of these findings to the purported anxiolytic activity of 5-HT3 receptor antagonists.
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PMID:Chronic administration of the 5-HT3 receptor antagonist BRL 43694; effects on reflex epilepsy and social behaviour of the Mongolian gerbil. 216 51

There are differences between young and adult organisms regarding toxokinetic aspects and clinical manifestations of heavy metal intoxications. Chronically, toxic Cd intake causes a microcytotic hypochromic anemia in young rats at lower exposure levels and after shorter exposure periods than in adult animals. Cd absorption is increased by co-administration of milk and in conjunction with iron deficiency. After long exposure periods toxic Cd concentrations accumulate in the kidney cortex; this process starts very early in life. In 3-year-old children Cd concentrations in the kidney can reach up to one-third of those found in adults. Hg++ and methyl-Hg can cause Hg encephalopathia, and frequently cause mental retardation in adults. Correspondingly, Hg++ accumulation in the brains of suckling rats is approx. 10 times higher than in grown animals. Milk increases the bioavailability of Hg++. In suckling rats Hg is bound to a greater extent to ligands in the erythrocytes. Methyl-Hg concentrations in breast milk reach 5% of those in maternal plasma and that is a severe hazard for breastfed children of exposed mothers. Toxic Pb concentrations can lead to Pb encephalopathia. A high percentage of surviving children have seizures and show signs of mental retardation. Anemia and reduced intelligence scores were recently observed in children after exposure to very low levels of Pb. Pb absorption is increased in children and after co-administration of milk. There are no definite proofs for carcinogenesis or mutagenesis after oral exposure to Cd, Hg, and Pb in man. Heavy metal concentrations were found in the same order of magnitude in commercial infant formulas and in breast milk. When infant formulas are reconstituted with contaminated tap water, however, Pb and Cd concentrations can be much higher. The average heavy metal uptake from such diets exceeds the provisional tolerable weekly intake levels set by the WHO for adults, calculated on the basis of an average food intake and a downscaled body weight. These considerations do not even provide for differences in absorption and distribution or for the increased sensitivity of children to heavy metal exposure. However, dilution effects for essential heavy metals were observed in fast-growing young children; this effect might be extrapolated to toxic metals. These theoretical considerations are compared with epidemiological evidence. A health statistic from Baltimore shows a decline of Pb intoxications in infants. This observation correlates with a simultaneous decline in exposure to Pb which was due, for example, to decreased use of lead dyes in house paints and the abolition of tin cans for infant food.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[The toxicological estimation of the heavy metal content (Cd, Hg, Pb) in food for infants and small children]. 218

Hypernatremia is a common electrolyte disturbance, most often caused by volume depletion. Hypernatremia due to sodium excess occurs less frequently, and fatal hypernatremia solely from ingestion of table salt is rare. We describe a 41-year-old man who had seizures and hypernatremia after ingestion of a supersaturated salt water solution intended for gargling. He had consumed approximately a third cup of table salt (approximately 70 to 90 g of salt or 1,200 to 1,500 meq of sodium). His initial serum sodium concentration was 209 meq/liter. Hypotonic fluid therapy was given to provide free water and to correct the hypernatremia gradually. Our patient, however, failed to recover from the initial insult and died 3 days later. Review of the literature revealed 10 adult and 20 pediatric cases of hypernatremia attributable to exogenous intake of salt. The type of therapy (fluid or peritoneal dialysis), the type of fluid used, and the rate of correction of hypernatremia did not influence survival. The age of the patient and the initial serum sodium concentration were the most important prognostic indicators. Both very young patients and those with lesser degrees of hypernatremia had a better rate of survival than did other patients. In addition, our review illustrates the surprisingly small amount of salt that can cause severe hypernatremia and the danger of using salt or saline as an emetic.
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PMID:Fatal hypernatremia from exogenous salt intake: report of a case and review of the literature. 201 96

Adult female, Fischer-344 rats were exposed to 275 mg/kg of tris(2-chloroethyl)phosphate (TRCP) by gavage. TRCP produced consistent signs of convulsive activity within 60-90 min after dosing and extensive loss of CAT hippocampal pyramidal cells when examined 7 days after dosing. At the light microscopic level, toxic effects of TRCP on pyramidal cells in the CA3 and CA4 regions and on granule cells in the dentate gyrus were less severe than those on the CA1 cells. The seizure-related and neurohistological effects of TRCP were significantly attenuated by pretreatment with atropine or chlordizepoxide, suggesting that the hippocampal damage was related to the seizures produced by TRCP. In a second experiment designed to assess the potential health risk associated with TRCP, exposed rats were mildly impaired in the acquisition of a reference memory task in a water maze. However, TRCP-exposed rats were consistently impaired in performing a repeated acquisition task in the water maze. These data underscore the potential health risk associated with exposure to TRCP and support the conclusion that the hippocampus is intimately involved in spatial memory in rats.
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PMID:Acute exposure to tris(2-chloroethyl)phosphate produces hippocampal neuronal loss and impairs learning in rats. 225 15


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