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

The effect of compression rate on onset of high-pressure convulsions has been studied in 14 vertebrate species, as well as in 10 mouse strains and 4 rat strains. Compression rate effects were observed in 9 of the 14 species. They appear to be independent of exposure temperature, correlate only very loosely with phylogenetic position, and appear to reflect species-specific compensatory mechanisms grafted onto an underlying convulsion-producing effect of high hydrostatic pressure. Five vertebrate species distributed among three of the four classes tested failed to show a significant degree of compression rate dependence of high-pressure neurological syndrome (HPNS) convulsion thresholds. The implications of this finding for the formulation of hypotheses regarding the biophysical basis for HPNS convulsions has been discussed. Comparison of intrinsic HPNS susceptibility in different species, in the light of these findings, requires that the comparison be made at a common compression rate. Four of the five lower vertebrate species fall consistently into the category showing high HPNS convulsion threshold pressures regardless of the compression rate employed, whereas the two primates and the one carnivore tested equally consistently fall in the low convulsion threshold pressure category. The data suggest a parallel between the degree of brain development and the relative HPNS susceptibility of a given species and contrast with the inverse relations observed during maturation of newborn mice and rats. The results are compared with data for other convulsants and suggest grouping HPNS and pentylenetetrazole seizures as against electroshock, hyperoxic, flurothyl, strychine, or picrotoxin convulsions.
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PMID:Comparative physiology of the high-pressure neurological syndrome--compression rate effects. 11 Jul 55

Grand mal type of sequential spike discharges at 8-12 cps are rare as interseizure phenomena. When the grand mal component is prominent, it usually indicates a greater tendency for major convulsions. The case of a 15 year old girl who developed akinetic seizures along with her menarche and whose electroencephalogram showed recurring sharp waves at 10-11 cps, is reported, and its clinical significance discussed.
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PMID:"Grand mal type" of spike discharge as interseizure phenomenon. 11 38

The mechanisms of the anticonvulsant activity of cannabidiol (CBD) and the central excitation of delta 9-tetrahydrocannabinol (delta 9-THC) were investigated electrophysiologically with conscious, unrestrained cobalt epileptic rats. The well-known antiepileptics, trimethadione (TMO), ethosuximide (ESM), and phenytoin (PHT), were included as reference drugs. Direct measurements were made of spontaneously firing, epileptic potentials from a primary focus on the parietal cortex and convulsions were monitored visually. ESM and TMO decreased the frequency of focal potentials, but PHT and CBD exerted no such effect. Although CBD did not suppress the focal abnormality, it did abolish jaw and limb clonus; in contrast, delta 9-THC markedly increased the frequency of focal potentials, evoked generalized bursts of polyspikes, and produced frank convlusions. 11-OH-delta 9-THC, the major metabolite of delta 9-THC, displayed only one of the excitatory properties of the parent compound: production of bursts of polyspikes. In contrast to delta 9-THC and its 11-OH metabolite, CBD, even in very high doses, did not induce any excitatory effects or convulsions. The present study provides the first evidence that CBD exerts anticonvulsant activity against the motor manifestations of a focal epilepsy, and that the mechanism of the effect may involve a depression of seizure generation or spread in the CNS.
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PMID:The influence of cannabidiol and delta 9-tetrahydrocannabinol on cobalt epilepsy in rats. 11 6

Isolated infantile convulsions were noted in 206 patients (13%) of 1,572 patients who underwent cortical resection for medically refractory focal epilepsy at the Montreal Neurological Institute over the period 1928 through 1977. In 59 patients (29% of the 206), the isolated infantile convulsion was associated with an identifiable febrile systemic or neural illness. In 54 patients (26%), there was a definite history of cerebral birth injury in addition to the isolated infantile convulsions. Twenty patients (10%) had some other potential etiological factor for the later development of seizures, such as postnatal head injury, Sturge-Weber syndrome, etc., in addition to the isolated infantile convulsions. In 95 patients, 6% of the total 1,572 patient series and 41% of those with isolated infantile convulsions, the latter was the sole apparent cause for the later development of recurring seizures. Although this was the case in a small but significant percentage in this series of patients, more frequently, the isolated infantile convulsion represents a manifestation of invasion of the brain by an infectious agent of a systemic or brain disease, or is a harbinger of the later development of a seizure tendency due to some other preexisting etiological factor.
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PMID:Relative significance of isolated infantile convulsions as a primary cause of focal epilepsy. 11 7

The author examined the cerebral schistosomiasis japonica (CSJ) in the Philippines which is one of the areas heavily infected with S. japonicum. Seventy-five subjects were selected randomly from 307 patients with CSJ, who showed neurological symptoms such as convulsions, paroxysmal disturbance of consciousness and hemiparesis. The mean age of the subjects was 33. Of the 71 patients who had paroxysmal disease, 54 had convulsions, in 33 of which it was of the Jacksonian type, and 24 had psychomotor seizures and 1 autonomic seizures. Thus, 58 patients or 82% of the paroxysmal disease group showed a sign of the localized lesion of the brain. Fifty-one patients (72%) of this group had attacks more than once a month, and the onset of the paroxysmal disease was later than 20 years old in 49 (69%). EEGs were judged as abnormal in 24 (32% of total subjects), borderline in 13 (17%) and normal in 38 (51%). The characteristic abnormal or borderline findings of EEG were random and paroxysmal slow waves with asymmetry. Discussion was made in reference to the strong suspicion that the cerebral symptoms of the subjects, the paroxysmal diseases in particular, were a syndrome associated with Schistosoma japonicum and to the difference between CSJ in Japan and that in the Philippines.
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PMID:Clinical studies on cerebral schistosomiasis japonica in the Philippines. 11 11

Intraventricular injection of 5,7-dihydroxytryptamine, selective destruction of descending serotoninergic neurons by 5,6-dihydroxytryptamine or electrolytic and chemical lesions of the nucleus raphe dorsalis did not affect the electroconvulsive threshold in rats. No effect was observed after the systemic administration of drugs known to increase central serotonin transmission, such as quipazine, m-chlorophenylpiperazine, and moderate doses of d-fenfluramine, whereas p-chlorophenylalanine, an inhibitor of serotonin synthesis, decreased seizure susceptibility. The anticonvulsant activity of carbamazepine was not modified in animals with the same experimental lesions. The results, in relation to the high selectivity of the experimental procedures employed to deplete brain and spinal cord serotonin, do not bear out any involvement of serotonin in the tonic component of electrically induced convulsions or in the action of carbamazepine.
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PMID:Evidence against serotonin involvement in the tonic component of electrically induced convulsions and in carbamazepine anticonvulsant activity. 12 May 46

Nine cases of childhood epilepsy manifesting motor convulsions uncontrolled despite high levels of phenytoin (PHT) were studied clinically and electroencephalographically. These cases consisted of five cases of partial seizures without impairment of consciousness, two cases of partial seizures (occasionally generalized seizures beginning locally), one case of predominantly unilateral seizures, and one case of generalized tonic-clonic seizures. the onset of seizures was at a rather early age, between 3 months and 9 years, and under 3 years of age in eight cases. All cases had single or multiple, cortical epileptic foci in EEG. The projection of spikes was localized to a rather limited area. Seizures of these patients were frequent. All cases, except one, did not respond to other medication. Convulsive seizures with cortical focal spike foci in EEG uncontrolled despite high levels of PHT were thought to have poor responsiveness to not only PHT itself, but also to other anticonvulsants.
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PMID:Childhood epilepsy uncontrolled by phenytoin: clinical and electroencephalographic study. 12 93

Fukuyama type Congenital Muscular Dystrophy, inherited autosomal-recessively, is characterized by muscular dystrophy associated with severe mental retardation and epileptic convulsions. By examining 56 cases, followed for more than three years, 75 EEG records from 40 patients and visual evoked potentials from 11 patients with reference to autopsied materials, the authors aimed at clarifying the causative relationship between congenital central nervous system (CNS) lesions and childhood epilepsy. In 36 out of 56 cases diffuse epileptic seizures were observed with onset at 1.64 +/- 1.01 years average. In 32/36 cases seizures developed before 3 years of age. In 51/75 EEGs focal paroxysmal discharges (FPD), fronto-contro-parietal in younger and centro-occipital in older cases, were observed. Abnormal basic activities (ABA), diffuse-alpha-activity and/or abundant or extreme spindles, were observed more often in older than younger cases. The incidence of FPD was similar between convulsive and non-convulsive cases, but ABA predominated in the former, VEP revealed abnormal findings in 64% of 11 cases examined. Of the CNS pathology, consisting of cerebral and cerebellar gyral abnormalities and a hypoplastic corticospinal tract, the gyral lesions (verrucous polymicrogyria with adhesions of adjacent gyri and cellular disarrangement) were thought to be lesions causing epilepsy. Cortical nonprogressive gyral lesions occurring around the second trimester could cause FPD and clinical diffuse epileptic seizures develop with other factors concerned with ABA.
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PMID:Fukuyama type congenital muscular dystrophy as a natural model of childhood epilepsy. 12 66

Study of 100 children with grand mal convulsive disorders and 100 medically healthy children of matching age showed significantly lower plasma levels of vitamin E in the former (means 632.2 +/- 17.3 and 822.5 +/- 21.8 micrograms/dl respectively; p less than 0.001). This finding accords with the ability to prevent seizures in rodents by giving alpha-tocopherol before exposing them to a convulsion-inducing environment.
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PMID:Vitamin E deficiency and seizures in animals and man. 12 40

Several observations in Man as well as in animals have stressed the importance of specific afferents in triggering some focal cortical fits. The authors report an analysis of the role of various afferents on the activity of a precentral focus in the monkey. The chronic focus was created on one adult female monkey by subpial injection of alumina cream in the motor area of the left foot. Typical seizures were clonic and local. The most striking feature was that movement or, more generally, proprioceptive afferents from the concerned leg could elicit and maintain these motor fits. This assumption was verified by curaryzing the animal with succinyl-choline. In this condition, the number of attacks was strongly reduced. Since there was no lowering of excitability at the central level, as shown by direct stimulation of the perifocal area, this decrease seems to result from the lack of triggering mechanisms. If this is the case, one should be able to elicit seizures by proprioceptive afferent volleys coming from the concerned leg. In fact, although passive motion was not very effective (the reason probably being the decrease of the back-ground activity of stretch receptors under curare), direct electrical intramuscular stimulation was always followed by an attack. Similar stimulation of the opposite leg was ineffective. These results are discussed. The role of the "motor cortex proprioceptive feedback" in jacksonian progression of motor seizures is debated. The same concept is applied to "startle epilepsy", for which a physiological hypothesis is purposed.
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PMID:[Analysis of a "movement epilepsy" bearing a rolandic focus in a monkey]. 12 50


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