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

Two patients with status epilepticus due to specific conditions were examined using MRI and stable Xe/CT CBF. [Case 1] A 30-year-old woman developed a grand mal seizure during delivery. She was comatose, and MRI revealed abnormal high intensity areas bilateral basal ganglia, compatible with eclampsia. Regional CBF was decreased in bilateral occipital lobes and right basal ganglia. Six days after onset. Regional gray matter flow was increased, especially in the thalami and basal ganglia. [Case 2] The patient is a 31-year-old male diagnosed with temporal lobe epilepsy since 10 years. At the onset, he had a prolonged right hemiconvulsion followed by generalized tonic-clonic convulsion. MRI 13 days after onset showed left hemispheric edematous swelling of gray matter. Stable Xe/CT 3 weeks after onset demonstrated increased cortical CBF corresponding to edematous area. The results suggested that regional CBF decreased immediately after status epilepticus and then increased for 1-3 weeks in the interictal period. We speculate that the energy debt incurred during prolonged seizure causes relative ischemic condition in the neurons, with the increase in CBF resulting from accelerated energy production for a long period.
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PMID:Regional cerebral blood flow after status epilepticus. 1075 Mar 44

Development of functional neuroimaging is contributed to diagnosis and treatment in epilepsy patients. The dipole analysis of interictal spikes on EEG or MEG provides 3D-localization of the irritable zone. Interictal and ictal CBF-SPECT reveals the local change in CBF associated to epileptic focus. Three-dimensional stereotactic surface projection (3D-SSP) of SPECT is useful to recognize the seizure generation area. Furthermore, Subtraction ictal SPECT coregistration of MRI (SISCOM), that is fusion image of anatomical and functional brain images, is beneficial to understand the localization of seizure-induced hyperperfusion area. During epilepsy surgery, image-guided system makes less-invasive and accurate surgery possible. Functional image-guided surgery for epilepsy will be available in near future.
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PMID:[Three-dimensional neuroimaging in diagnosis and surgical treatment for epilepsy]. 1510 45

The results of clinical and experimental studies on epilepsy associated with focal cortical dysplasia (FCD) are presented. We have been interested in the findings of abnormal increases in the numbers of small vessels in specimens of FCD resected from epilepsy patients. In the clinical study of 13 patients with epilepsy, specimens of FCD or dysembryoplastic neuroepithelial tumor (DNT) were examined using immunohistochemistry. The number of vessels in both lesions were greater than those in cortical specimens of autopsy cases without epilepsy. Because the vessels showed negative staining of VEGF, it was thought that the phenomenon of increase in the number of vessels was simply a hypervascularity, not a neovascularity. The local hypervascularity was expected to show local hyperperfusion in CBF-SPECT study, but interictal SPECT demonstrated local hypoperfusion and ictal SPECT showed hyperperfusion. This may have been caused by a functional change in those vessels. In the experimental study, we tried to make a new animal model of FCD to study epileptogenicity of FCD. When kainic acid had been infused into the neocortex in the neonatal rats, FCD was induced in adult Wistar rats. Histopathological examination revealed cortical dyslamination and abnormal neurons. On EEG, local spike bursts were elicited from the lesions, however, clinical seizures were not detected. Although the data are preliminary and observation over a longer period is required to determine whether spontaneous seizures will occur in this model, it is expected that this new model will be useful for studying epilepsy associated with FCD.
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PMID:Clinical and experimental studies of epilepsy associated with focal cortical dysplasia. 1514 12

There is broad agreement that generalized tonic-clonic seizures (GTCS) and normal somatosensory stimulation are associated with increases in regional CBF. However, the data regarding CBF changes during absence seizures are controversial. Electrophysiologic studies in WAG/Rij rats, an established animal model of absence seizures, have shown spike-wave discharges (SWD) that are largest in the perioral somatosensory cortex while sparing the visual cortex. Recent functional magnetic resonance imaging (fMRI) studies in the same model have also shown localized increases in fMRI signals in the perioral somatosensory cortex during SWD. Because fMRI signals are only indirectly related to neuronal activity, the authors directly measured CBF and neuronal activity from specific microdomains of the WAG/Rij cortex using a specially designed probe combining laser-Doppler flowmetry and extra-cellular microelectrode recordings under fentanyl/haloperidol anesthesia. Using this approach, parallel increases in neuronal activity and CBF were observed during SWD in the whisker somatosensory (barrel) cortex, whereas the visual cortex showed no significant changes. For comparison, these measurements were repeated during somatosensory (whisker) stimulation, and bicuculline-induced GTCS in the same animals. Interestingly, whisker stimulation increased neuronal activity and CBF in the barrel cortex more than during SWD. During GTCS, much larger increases that included both the somatosensory and visual cortex were observed. Thus, SWD in this model produce parallel localized increases in neuronal activity and CBF with similar distribution to somatosensory stimulation, whereas GTCS produce larger and more widespread changes. The normal response to somatosensory stimulation appears to be poised between two abnormal responses produced by two physiologically different types of seizures.
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PMID:Relative changes in cerebral blood flow and neuronal activity in local microdomains during generalized seizures. 1535 26

The role of neuronal nitric oxide (NO) in the cerebrovascular response to partial seizures induced by intrahippocampal injection of kainate (KA) was investigated in mice deleted for the neuronal NO synthase gene (nNOS-/-) and in wild-type controls (WT). A second group of WT mice received the nNOS inhibitor, 7-nitroindazole (WT-7NI). Local cerebral blood flow (LCBF) was measured using the quantitative (14)C-iodoantipyrine method. Within the epileptic focus, all three groups of seizing mice (WT, WT-7NI, and nNOS-/-) showed significant 26-88% LCBF increases in ipsilateral hippocampus, compared to saline-injected mice. Contralaterally to the epileptic focus, KA seizures induced a 21-47% LCBF decreases in hippocampus and limbic cortex of WT mice and in most contralateral brain structures of nNOS-/- mice, while WT-7NI mice showed no contralateral CBF change. Neuronal NO appears to be not involved in the cerebrovascular response within the epileptic focus, but may rather have a role in the maintenance of distant LCBF regulation during seizures.
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PMID:Role of nitric oxide in cerebral blood flow changes during kainate seizures in mice: genetic and pharmacological approaches. 1568 55

The purpose of the present study was to explore the seizure-induced changes in Bad (Bcl-2-associated death protein), 14-3-3, phosphoBad, Bcl-2 and Bcl-XL expression in the rat model of focal limbic seizure. Unilateral intra-amygdaloid injection of kainic acid (KA) was made to induce seizure. Electroencephalogram (EEG) and regional cerebral flow (r-CBF) were monitored continuously. Diazepam (30 mg/kg) was administered to terminate the seizure. The apoptotic and surviving neurons in the hippocampus were observed by terminal deoxynucleotidyl transferrase-mediated dUTP nick end labeling (TUNEL) and cresyl violet staining, the expression of Bad, 14-3-3, phosphoBad, Bcl-2 and Bcl-XL were detected with immunofluorescence, Western blot and immunoprecipitation. The results showed that TUNEL-positive neurons appeared at 8 h and reached maximum at 24 h following seizure cessation within the ipsilateral CA3 subfield of the hippocampus. Seizure induced the dephosphorylation of Bad and the dissociation of Bad from its chaperone protein 14-3-3 and subsequent dimerization of Bad with Bcl-XL. The expression of phosphoBad decreased and Bcl-2 increased. There was little change in r-CBF after the seizure. These results suggest that seizure leads to a dephosphorylation of Bad and an upregulation of Bcl-2. Dephosphorylation of Bad may be injurious while the upregulation of Bcl-2 may be protective to the brain damage induced by seizures, but not related with r-CBF.
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PMID:[Dephosphorelation of Bad and upregulation of Bcl-2 in hippocampus of rats following limbic seizure induced by kainic acid injection into amygdaloid nucleus]. 1596 25

Periodic lateralized epileptiform discharges (PLEDs), which are known as unusual electroencephalogram (EEG) patterns, are described in a patient who had stroke and seizures. This patient underwent Tc-99m HMPAO (hexamethyl propylene amine oxime) brain single photon emission computed tomography (SPECT) imaging both during PLEDs on EEG and after the cessation of PLEDs. The initial SPECT study revealed increased CBF in the left frontal and parietal cortex extending through the left temporal region and in the left basal ganglium. After the PLEDs disappeared, the second SPECT study showed decreased perfusion on the left frontal and parietal region in the brain. Brain SPECT findings supported the contention that PLEDs may be an ictal phenomenon. Here we also present a review on PLEDs and contributions of brain SPECT as a functional imaging modality to investigate the underlying mechanism of this interesting EEG pattern.
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PMID:SPECT in periodic lateralized epileptiform discharges (PLEDs): a case report on PLEDs. 1671 55

In the present study, L-pGlu-(1-benzyl)-L-His-L-ProNH(2) (NP-355), a newer CNS active thyrotropin-releasing hormone (TRH) analog was evaluated for its antiepileptic potential. NP-355 (5, 10 and 20 micromol/kg; i.v.) pretreatment significantly delayed onset and reduced the frequency of convulsions in pentylenetetrazole-induced seizures. NP-355 was also found to be protective against picrotoxin- and kainic acid-induced seizures. Maximum electroshock-induced seizures were not protected even at 20 micromol/kg in mice. Effects of NP-355 on functional observation battery did not exhibit any undesirable effects. Moreover, the antiepileptic activity produced by NP-355 was observed without significantly altering mean arterial blood pressure. NP-355 significantly increases the CBF to 17+/-3% as compared to saline (6+/-2%). NP-355 (100, 300 and 1000 microM) produces a concentration-dependent depression (16%, 63% and 77%, respectively) of the peak sodium current. NP-355 did not alter neurobehavioral parameters. This study demonstrates that NP-355 has potential antiepileptic activity and devoid of undesirable effects.
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PMID:Neuropharmacological profile of L-pGlu-(1-benzyl)-L-His-L-ProNH2, a newer thyrotropin-releasing hormone analog: effects on seizure models, sodium current, cerebral blood flow and behavioral parameters. 1983 80

We reviewed MRI and SPECT images in 10 patients with septo-optic dysplasia (SOD). MRI was performed in all of them. Six of them had bilateral optic nerve atrophy and abnormality of midline brain structures (e. g., septum pellucidum, corpus callosum). Four cases had one-sided optic nerve atrophy. They have ipsilateral or bilateral cortical dysplasia. It may suggest that one of the pathogenesis of SOD is a disruption of the anterior cerebral artery at embryonic site. SPECT was performed in 3 patients with cortical dysplasia. At cortical dysplasia area, CBF-SPECT and IMZ-SPECT showed the same RI count as the normal cortex. This finding is compatible with the fact that few patients with SOD have epileptic seizures.
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PMID:[Review of images in children with septo-optic dysplasia based on MRI and SPECT]. 2140 Sep 24

Non-invasive pulsed arterial spin labeling (PASL) MRI is a method to study brain perfusion that does not require the administration of a contrast agent, which makes it a valuable diagnostic tool as it reduces cost and side effects. The purpose of the present study was to establish the viability of PASL as an alternative to dynamic susceptibility contrast (DSC-MRI) and other perfusion imaging methods in characterizing changes in perfusion patterns caused by seizures in epileptic patients. We evaluated 19 patients with PASL. Of these, the 9 affected by high-frequency seizures were observed during the peri-ictal period (within 5hours since the last seizure), while the 10 patients affected by low-frequency seizures were observed in the post-ictal period. For comparison, 17/19 patients were also evaluated with DSC-MRI and CBF/CBV. PASL imaging showed focal vascular changes, which allowed the classification of patients in three categories: 8 patients characterized by increased perfusion, 4 patients with normal perfusion and 7 patients with decreased perfusion. PASL perfusion imaging findings were comparable to those obtained by DSC-MRI. Since PASL is a) sensitive to vascular alterations induced by epileptic seizures, b) comparable to DSC-MRI for detecting perfusion asymmetries, c) potentially capable of detecting time-related perfusion changes, it can be recommended for repeated evaluations, to identify the epileptic focus, and in follow-up and/or therapy-response assessment.
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PMID:Cerebral perfusion alterations in epileptic patients during peri-ictal and post-ictal phase: PASL vs DSC-MRI. 2362 32


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