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

The aims of the present study were to investigate the anticonvulsant activity and behavioral toxicity of FrPbAII using freely moving Wistar rats. Moreover, the effectiveness of this compound against chemical convulsants was compared to that of the inhibitor of the GABAergic uptake, nipecotic acid. Our results show that FrPbAII was effective against seizures induced by the i.c.v. injection of pilocarpine (ED(50) = 0.05 microg/animal), picrotoxin (ED(50) = 0.02 microg/animal), kainic acid (ED(50) = 0.2 microg/animal) and the systemic administration of PTZ (ED(50) = 0.03 microg/animal). The anticonvulsant effect of FrPbAII differed from that of nipecotic acid in potency, as the doses needed to block the seizures were more than 10 folds lower. Toxicity assays revealed that in the rotarod, the toxic dose of the FrPbAII is 1.33 microg/animal, and the therapeutic indexes were calculated for each convulsant. Furthermore, the spontaneous locomotor activity of treated animals was not altered when compared to control animals but differed from the animals treated with nipecotic acid. Still, FrPbAII did not induce changes in any of the behavioral parameters analyzed. Finally, when tested for cognitive impairments in the Morris water maze, the i.c.v. injection of FrPbAII did not alter escape latencies of treated animals. These findings indicate that the novel GABA uptake inhibitor is a potent anticonvulsant with mild side-effects when administered to Wistar rats.
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PMID:Neuropharmacological profile of FrPbAII, purified from the venom of the social spider Parawixia bistriata (Araneae, Araneidae), in Wistar rats. 1708 49

Ample evidence points to the dentate gyrus as anatomical region for persistent neurogenesis in the adult mammalian brain. This has been confirmed in a variety of animal models under physiological as well as pathophysiological conditions. Notwithstanding, similar experiments are difficult to perform in humans. Postmortem studies demonstrated persisting neurogenesis in the elderly human brain. In addition, neural precursor cells can be isolated from surgical specimens obtained from patients with intractable temporal lobe epilepsy (TLE) and propagated or differentiated into neuronal and glial lineages. It remains a controversial issue, whether epileptic seizures have an effect on or even increase hippocampal neurogenesis in humans. Recent data support the notion that seizures induce neurogenesis in young patients, whereas the capacity of neuronal recruitment and proliferation decreases with age. Animal models of TLE further indicate that these newly generated neurons integrate into epileptogenic networks and contribute to increased seizure susceptibility. However, pathomorphological disturbances within the epileptic hippocampus, such as granule cell dispersion (GCD), may not directly result from compromised neurogenesis. Still, the majority of adult TLE patients present with significant dentate granule cell loss at an end stage of the disease, which relates to severe memory and learning disabilities. In conclusion, surgical specimens obtained from TLE patients represent an important tool to study mechanisms of stem cell recruitment, proliferation and differentiation in the human brain. In addition, increasing availability of surgical specimens opens new avenues to systematically explore disease pathomechanisms in chronic epilepsies.
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PMID:Neurogenesis in the human hippocampus and its relevance to temporal lobe epilepsies. 1852 1

In this review we systematically assess our current knowledge about psychogenic non-epileptic seizures (PNES), epidemiology, etiology, with an emphasis on the diagnostic issues. Relevant studies were identified by searching the electronic databases. Case reports were not considered. Articles were included when published after 1980 up till 2005 (26 years). A total of 84 papers were identified; 60 of which were actual studies. Most studies have serious methodological limitations. An open non-randomized design, comparing patients with PNES to patients with epilepsy is the dominant design. The incidence of PNES in the general population is low. However, a relatively high prevalence is seen in patients referred to epilepsy centres (15-30%). Caution is needed in the clinical interpretation of ictal features suggested to be pathognomic for PNES. Video-EEG is widely considered to be the gold standard for diagnosing PNES. Still the differential diagnosis epileptic/non-epileptic seizures can be difficult. Despite the current available technical facilities, the mean latency between onset of PNES and final diagnosis as being non-epileptic and psychogenic is approximately 7 years. One of the reasons for diagnostic delay is that the diagnosis of PNES is often limited to a 'negative' process and consequently PNES is characterized as a 'non-disease' (i.e. 'not epilepsy'). The psychological diagnosis is thus an important, although not a conclusive, 'second phase' aspect of medical decision making. Specific relations between seizure presentation and underlying psychological mechanisms are not conclusive. A classification between major motor manifestations and unresponsiveness is recognized. With respect to psychological etiology, a heterogeneous set of factors have been identified that may be involved in the causation, development and provocation of PNES.
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PMID:Psychogenic non-epileptic seizures--diagnostic issues: a critical review. 1901 31

Epilepsy is a frequent symptom in inborn errors of metabolism, with virtually no specific seizure types or EEG signatures. It is most important to look quickly for those few inborn errors of metabolism in which specific therapies such as supplementation of cofactors or diets can make all the difference. If these investigations remain negative, epilepsy has to be treated with conventional antiepileptic drugs. Still, epilepsy is a potentially treatable symptom of many inborn errors of metabolism, and optimal treatment is of great importance for patients and their families.
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PMID:Epilepsy and inborn errors of metabolism in children. 1964 11

Previous human studies have demonstrated that midazolam-induced signal changes on scalp EEG recording include widespread augmentation of sigma-oscillations and that the amplitude of such oscillations is correlated to the severity of midazolam-induced amnesia. Still unanswered questions include whether midazolam-induced sigma-augmentation also involves the medial temporal region, which plays a role in memory encoding. Taking advantage of rare and unique opportunities to monitor neuronal activities using intracranial electrocorticography (ECoG) recording, we determined how intravenous administration of midazolam elicited spectral frequency changes in the human cerebral cortex, including the medial temporal region. We studied three children with focal epilepsy who underwent subdural electrode placement and extraoperative ECoG recording for subsequent resection of the seizure focus; an intravenous bolus of midazolam was given to abort an ongoing simple partial seizure or to provide sedation prior to induction of general anesthesia. 'Midazolam-induced ECoG frequency alteration' in sites distant from the seizure focus was sequentially animated on their individual three-dimensional MR images. The common ECoG changes induced by midazolam included gradual augmentation of sigma-oscillations (12-16 Hz) in the widespread non-epileptic regions, including the medial temporal region. The spatial and temporal alteration of ECoG spectral frequency pattern can be appreciated via animation movies. Midazolam-induced sigma-augmentation was observed in the medial temporal region in our relatively small cohort of human subjects. In-vivo animation of ECoG spectral measures provided a unique situation to study the effect of midazolam on neuronal processing in the deep brain regions.
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PMID:In-vivo animation of midazolam-induced electrocorticographic changes in humans. 1973 66

Ischemic and hemorrhagic strokes are established etiological factors for recurrent seizures. Still, only few prospective data are available to predict post-stroke epilepsy and to choose the best point in time and anticonvulsive agent for treatment. In a prospective study we evaluated 264 consecutive stroke patients and assessed their post-stroke epilepsy risk within a follow-up of 1 year. Data on ten risk items concerning the stroke localisation, persisting neurological deficit, stroke subtype, established diagnosis of vascular encephalopathy, early- and late-onset seizures were collected using a post-stroke epilepsy risk scale (PoSERS). All patients underwent brain imaging with either CT, MRI or both and 148 patients underwent electroencephalography. The overall frequency of early-onset seizures within 14 days was 4.5%, of at least one late seizure 6.4% and of epilepsy 3.8%. Chi-Square tests showed significantly higher relative frequencies of seven of the ten clinical characteristics in post-stroke epilepsy patients. The total scale showed moderate sensitivity (70%) and positive predictive value (87.5%) while specificity (99.6%) and negative predictive value (98.8%) were relatively high. The EEG showed little value in predicting post-stroke epilepsy. The PoSERS appears to be a valuable tool to predict the risk for post-stroke epilepsy within the first few days after a stroke.
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PMID:Prospective evaluation of a post-stroke epilepsy risk scale. 2030 71

So far little is known about the long-term outcome of difficult-to-treat epilepsy syndromes of childhood. The aim of this study was to evaluate precise long-term data concerning the course of such epilepsies after 20 years. By means of a questionnaire we assessed the current situation of patients who had been treated as in-patients at the Department of Children and Adolescents at our Centre due to their difficult-to-treat epilepsy. Of 287 patients who met the inclusion criteria (diagnosis of difficult-to-treat epilepsy according to the final hospital record and hospitalisation for a therapy-resistant epilepsy), 176 were traced successfully and 81 completed and returned the questionnaire. A significant improvement of seizure frequency was reported by 49.7% and complete remission (with or without AEDs) by 25.9% of the patients. Social integration and work was attained by 21%. Cognitive impairment and treatment with more than 3 antiepileptic drugs proved to be significant negative outcome predictors. Among the patient population addressed in this study a high percentage had neurological impairments and/or cognitive deficiencies. Still, with 25.9% an unexpectedly high proportion of patients reached complete clinical remission after 20 years. Our data indicate that the natural course of difficult-to-treat epilepsies of childhood may be better than previously suggested.
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PMID:Long-term outcome of difficult-to-treat epilepsy in childhood. 2085 33

Frontal lobe epilepsy (FLE) is considered the second most common type of the localization-related epilepsies of childhood. Still, the etiology of FLE in children, its impact on cognitive functioning and behavior, as well as the response to antiepileptic drug treatment in children has not been sufficiently studied. This review focuses on these aspects of FLE in childhood, and reveals that FLE in childhood is most often cryptogenic, and impacts on a broad range of cognitive functions. The nature and severity of cognitive deficits are highly variable, although impaired attention and executive functions are most frequent. Young age at seizure onset is the only potential risk factor for poor cognitive outcome that has been consistently reported. The behavioral disturbances associated with FLE are also highly variable, although attention deficit/hyperactivity disorder seems most frequent. In 40% of children with FLE satisfactory seizure control could not be achieved. This is a higher percentage than reported for the general population of children with epilepsy. Therefore, pediatric FLE, even if cryptogenic in nature, is frequently complicated by impairment of cognitive function, behavioral disturbances, and therapy-resistance. Given the impact of these complications, there is a need for studies of the etiology of frontal lobe epilepsy-associated cognitive and behavioral disturbances, as well as pharmacotherapy-resistance.
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PMID:Cognitive and behavioral complications of frontal lobe epilepsy in children: a review of the literature. 2148 Aug 82

Carbon monoxide (CO) is produced by heme oxygenase (HO)-catalyzed heme degradation to CO, iron, and biliverdin. HO has two active isoforms, HO-1 (inducible) and HO-2 (constitutive). HO-2, but not HO-1, is highly expressed in endothelial and smooth muscle cells and in adjacent astrocytes in the brain. HO-1 is expressed basally only in the spleen and liver but can be induced to a varying extent in most tissues. Elevating heme, protein phosphorylation, Ca(2+) influx, and Ca(2+)/calmodulin-dependent processes increase HO-2 activity. CO dilates cerebral arterioles and may constrict or dilate skeletal muscle and renal arterioles. Selected vasodilatory stimuli, including seizures, glutamatergic stimulation, hypoxia, hypotension, and ADP, increase CO, and the inhibition of HO attenuates the dilation to these stimuli. Astrocytic HO-2-derived CO causes glutamatergic dilation of pial arterioles. CO dilates by activating smooth muscle cell large-conductance Ca(2+)-activated K(+) (BK(Ca)) channels. CO binds to BK(Ca) channel-bound heme, leading to an increase in Ca(2+) sparks-to-BK(Ca) channel coupling. Also, CO may bind directly to the BK(Ca) channel at several locations. Endothelial nitric oxide and prostacyclin interact with HO/CO in circulatory regulation. In cerebral arterioles in vivo, in contrast to dilation to acute CO, a prolonged exposure of cerebral arterioles to elevated CO produces progressive constriction by inhibiting nitric oxide synthase. The HO/CO system is highly protective to the vasculature. CO suppresses apoptosis and inhibits components of endogenous oxidant-generating pathways. Bilirubin is a potent reactive oxygen species scavenger. Still many questions remain about the physiology and biochemistry of HO/CO in the circulatory system and about the function and dysfunction of this gaseous mediator system.
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PMID:Carbon monoxide as an endogenous vascular modulator. 2149 77

Electroencephalography (EEG) remains central to the investigation of epilepsy. This review discusses two clinical problems at the temporal extremes of neurophysiologic recording: evaluation of the clinical significance of individual spike discharges in benign epilepsy of childhood with centrotemporal spikes (BECTS), and prolonged (several days) continuous EEG monitoring in the ICU. BECTS is misdiagnosed often, and probably mis-treated often as well. Though the long-term outcome is usually excellent, it remains unclear whether the individual epileptiform discharges have a clinical effect. Answering this question is difficult, in part because of the natural evolution of the epilepsy and its different appearance depending on wakefulness or sleep state, and also due to substantial methodologic problems in measuring short and long-term cognitive effects. Continuous EEG (CEEG) recording has grown remarkably over the last 10 years. It has proved crucial in the diagnosis of nonconvulsive status epilepticus (NCSE), especially in the ICU, given the usual lack of obvious clinical signs of seizures in most of these patients, many of whom are critically ill. Much progress has been made in agreeing on terminology for the EEG findings, but diagnosis is still complicated. More efficient and reliable technology is being developed to help process the massive amount of data captured by CEEG and make it more useful (and in a timely fashion) clinically. Still, it is not completely clear which patients should be monitored, for how long, and what is the best role for CEEG in assessing and adjusting treatment once the diagnosis has been made. Investigators are using CEEG to study "seizure burden," to help determine what are the long-term effects of nonconvulsive seizures and NCSE, and to help guide treatment and improve outcome.
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PMID:Electroencephalography in clinical epilepsy research. 2182 21


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