Biomedical subjects

Kazumi Matsuda

Publications and source records attributed to Kazumi Matsuda.

10 recordsLinked to original sources

PubMed2006

A Kv4.2 truncation mutation in a patient with temporal lobe epilepsy.

Temporal lobe epilepsy (TLE) has a multifactorial etiology involving developmental, environmental, and genetic components. Here, we report a voltage-gated potassium channel gene mutation found in a TLE patient, namely a Kv4.2 truncation mutation. Kv4.2 channels, encoded by the KCND2 gene, mediate A currents in the brain. The identified mutation corresponds to an N587fsX1 amino acid change, predicted to produce a truncated Kv4.2 protein lacking the last 44 amino acids in the carboxyl terminal. Electrophysiological analysis indicates attenuated K+ current density in cells expressing this Kv4.2-N587fsX1 mutant channel, which is consistent with a model of aberrant neuronal excitability characteristic of TLE. Our observations, together with other lines of evidence, raise the intriguing possibility of a role for KCND2 in the etiology of TLE.

Action Potentials↗

PubMed2006

Postictal mania versus postictal psychosis: differences in clinical features, epileptogenic zone, and brain functional changes during postictal period.

PURPOSE: To clarify the differences between postictal mania (PIM) and postictal psychosis (PIP). METHODS: Five patients with PIM were compared to 17 patients with PIP, with respect to clinical, epileptological, electrophysiological, and neuroimaging features. PIM was distinguished from PIP by the symptoms observed in the postictal period based on the ICD-10 criteria. RESULTS: Postictal manic episodes lasted for a longer period than postictal psychotic episodes. Patients with PIM had more recurrent postictal episodes than patients with PIP. The age at onset of epilepsy in patients with PIM was older than that in patients with PIP. PIM was associated with frontal lobe and temporal lobe epilepsies, whereas PIP was associated with temporal lobe epilepsy. The estimated epileptogenic zone was on the language dominant side in PIM, whereas there was no predominant hemispheric laterality in PIP. Electroencephalography (EEG) performed during the early period of postictal manic and psychotic episodes showed decreased frequency of interictal epileptiform discharges in both PIM and PIP. Single-photon emission computed tomography (SPECT) during postictal manic and psychotic episodes showed increased perfusion in the temporal and/or frontal lobes in both PIM and PIP. Three patients with PIM showed increased perfusion during postictal episodes on bilateral or the language nondominant side, which were contralateral to the estimated epileptogenic zone, whereas three patients with PIP showed increased perfusion on the areas, which were ipsilateral to the estimated epileptogenic zone. CONCLUSIONS: PIM has a distinct position among the mental disorders observed in the postictal period.

Age of Onset↗

PubMed2006

Development of multi-dimensional action checklist for promoting new approaches in participatory occupational safety and health in small and medium-sized enterprises.

To meet diversified health needs in workplaces, especially in developed countries, occupational safety and health (OSH) activities should be extended. The objective of this study is to develop a new multi-dimensional action checklist that can support employers and workers in understanding a wide range of OSH activities and to promote participation in OSH in small and medium-sized enterprises (SMEs). The general structure of and specific items in the new action checklist were discussed in a focus group meeting with OSH specialists based upon the results of a literature review and our previous interviews with company employers and workers. To assure practicality and validity, several sessions were held to elicit the opinions of company members and, as a result, modifications were made. The new multi-dimensional action checklist was finally formulated consisting of 6 core areas, 9 technical areas, and 61 essential items. Each item was linked to a suitable section in the information guidebook that we developed concomitantly with the action checklist. Combined usage of the action checklist with the information guidebook would provide easily comprehended information and practical support. Intervention studies using this newly developed action checklist will clarify the effectiveness of the new approach to OSH in SMEs.

Cooperative Behavior↗

PubMed2005

Postictal mania associated with frontal lobe epilepsy.

A 38-year-old man, possibly with frontal lobe epilepsy, developed postictal mania. The changes in psychiatric symptoms and laboratory examinations over time were investigated in two episodes of postictal mania, using long-term electroencephalography with closed circuit television (EEG/CCTV) monitoring, magnetoencephalography (MEG), and single-photon emission computed tomography (SPECT) to elucidate the underlying mechanism of postictal mania. According to the clinical symptoms, the postictal manic episodes of this case had four phases: a lucid interval, manic phase, hypomanic phase, and recovery phase. EEG showed forced normalization during the florid manic phase. The serial findings of EEG, MEG, and SPECT during the postictal manic episodes suggest that functional changes in bilateral frontal lobes, especially the right frontal lobe, right temporal lobe, and right paralimbic area, are crucial in the development of postictal mania, and that these functional changes are dynamic.

Adult↗

PubMed2005

Autoantibodies and cell-mediated autoimmunity to NMDA-type GluRepsilon2 in patients with Rasmussen's encephalitis and chronic progressive epilepsia partialis continua.

PURPOSE: To evaluate antibody-mediated and cytotoxic T cell-mediated pathogenicity that has been implicated as the autoimmune pathophysiological mechanism in Rasmussen's encephalitis. METHODS: We examined autoantibodies against the N-methyl-d-aspartate glutamate receptor (NMDA-type GluR) epsilon2 subunit and its epitopes in serum and CSF samples from 20 patients [five histologically proven (definitive) Rasmussen's encephalitis with epilepsia partialis continua (EPC), four definitive Rasmussen's encephalitis without EPC, and 11 clinical Rasmussen's encephalitis with EPC]. We examined 3H-thymidine uptake into lymphocytes after stimulation by GluRs. RESULTS: All nine definitive patients (five patients with EPC and four without EPC), and 10 of 11 clinical Rasmussen's encephalitis patients had the autoantibodies. In four patients, the autoantibodies were absent in early stage when epileptic seizures had already become frequent, and appeared subsequently. In two patients, the autoantibodies persisted in the serum after frontal lobe resection or functional hemispherectomy, although epileptic seizures were completely controlled. Autoantibodies to the C2 epitope predominated, while autoantibodies to the extracellular N epitope were rare. The mean 3H-thymidine uptake ratios (stimulation by GluRepsilon2-containing homogenates/stimulation by PHA) were significantly higher in definitive and clinical Rasmussen encephalitis patients than in controls. The mean 3H-thymidine uptake ratios (relative to PHA) were significantly higher for GluRepsilon2-containing homogenate than for control homogenate or GluRdelta2-containing homogenate. CONCLUSIONS: Autoantibodies against GluRepsilon2 may be one of the diagnostic markers for Rasmussen's encephalitis with and without EPC. Patients have activated T cells stimulated by GluRepsilon2 in peripheral blood circulation. We speculate that cellular autoimmunity and the subsequent humoral autoimmunity against GluRepsilon2 may contribute to the pathophysiological processes in Rasmussen's encephalitis.

Adolescent↗

PubMed2005

Central-type benzodiazepine receptors and epileptogenesis: basic mechanisms and clinical validity.

PURPOSE: Gamma-aminobutyric acid (GABA)-A/benzodiazepine receptors (BZRs) play an important inhibitory role in epileptogenesis. [123I]Iomazenil (123I-IMZ) is a specific ligand for central-type (or neuronal-type) BNRs and is available for single-photon emission computed tomography (SPECT) in brain disorders. We demonstrated alterations of central-type BZRs in human focal epilepsies and their experimental models. METHODS: We examined interictal 123I-IMZ SPECT in patients with mesial temporal lobe epilepsy (MTLE; n = 19) with hippocampal sclerosis and neocortical epilepsy with focal cortical dysplasia (NE-CD; n = 18), and compared those with magnetic resonance imaging (MRI) and 123I-IMP SPECT (for regional cerebral blood flow). We also investigated in vitro autoradiography with (123)I-IMZ at various time courses in the intraamygdala kainate, amygdala kindling, and in-utero irradiation models. RESULTS: In MTLE patients, the epileptogenic hippocampus often showed decreases in both 123I-IMZ and 123I-IMP SPECT. Consistent with those, marked reduction of 125I-IMZ binding was observed in hippocampal CA1-3 regions of the kainate model, which clearly paralleled pyramidal neuronal loss. In contrast, 125I-IMZ binding was increased in the dentate gyrus at 1 month but returned to the normal level at 3-6 months, when frequent spontaneous seizures appeared. The amygdala-kindling model demonstrated similar increases in 125I-IMZ binding in the dentate gyrus without any changes in other brain regions. In NE-CD patients, the epileptogenic foci showed decreased 123I-IMZ binding with relatively normal 123I-IMP SPECT. 125I-IMZ binding also was decreased in the cerebral cortex, hippocampus (areas CA1, 2, and 4), and caudate/putamen of the in-utero irradiation model. CONCLUSIONS: These results indicate that central-type BZRs neuroimaging is useful for detection of epileptogenic foci, but their alterations differ between epilepsy subtypes and time-courses.

Adult↗

PubMed2004

Dystonic posturing associated with putaminal hyperperfusion depicted on subtraction SPECT.

PURPOSE: Dystonic posturing (DP) is one of the most reliable lateralizing indicators for temporal lobe epilepsy (TLE). We evaluated the ictal hyperperfusional areas in patients with DP by using ictal-interictal subtraction single-photon emission computed tomography (SPECT). METHODS: Ninety-seven patients were treated surgically for intractable TLE, and 39 patients underwent ictal and interictal SPECT studies with the same isotope. These patients were divided into three groups: group I with DP of the contralateral side extended to the epileptogenic focus, group II with elevated muscle tonus but without DP, and group III without DP or alteration of muscle tonus. Ictal, interictal SPECT and thin-slice magnetic resonance imaging (MRI) were overlaid by using the automatic multimodality registration program to construct ictal-interictal subtracted images of SPECT on MRI. RESULTS: Thirteen patients belonged to group I; 14, to group II; and 12, to group III. A statistically significant difference in hyperperfusion rate was observed in the putamen (10 patients in group I, three in group II and two in group III; p < 0.01) and mesial temporal lobe (10 patients in group I, seven in group II, and two in group III; p < 0.05) on the ipsilateral side of the epileptogenic focus. No statistically significant difference was observed for other ictal symptoms except ipsilateral upper-limb automatism (eight patients in group I, three in group II, and none in group III; p < 0.01). CONCLUSIONS: A strong correlation between DP and hyperperfusion in the putamen and mesial temporal lobe was demonstrated. Some patients showed a wide hyperperfusion area extending from the mesial temporal lobe to putamen, which may correspond to the propagation of epileptic discharges. Our results suggest a correlation between hyperperfusion of putamen and contralateral dystonic posturing.

Adolescent↗

PubMed2004

Long-term seizure outcome following resective surgery at National Epilepsy Center in Shizuoka, Japan.

We analyzed the seizure outcome of 357 patients who were followed for at least 2 years after resective surgeries; 282 underwent temporal lobe resection and 75 had extratemporal lobe resection. This study confirmed that resective surgery provides sustained, positive benefits with a high seizure-free rate of nearly 80% for most medically refractory patients. In patients with no MRI-detectable lesion who underwent extratemporal lobe resection, however, Engel's class I-II (seizure-free or rare seizures) was achieved in less than 50% of patients. High-resolution MRI should be performed at the early stage of disease in all patients with partial epilepsies. The findings would certainly urge clinicians to actively select surgical intervention.

Adolescent↗

PubMed2002

Quantitative analysis of benzodiazepine receptor in temporal lobe epilepsy: [(125)I]iomazenil autoradiographic study of surgically resected specimens.

PURPOSE: To evaluate the changes of the inhibitory neurotransmitter receptor system related to epileptogenesis by measuring central benzodiazepine receptors (BZDRs) in surgically resected specimens of temporal lobe epilepsy by using [(125)I]iomazenil autoradiography. METHODS: Surgically resected specimens were obtained from 66 temporal lobe epilepsy patients [51 with mesial temporal lobe epilepsy (MTLE) and 15 with non-MTLE] receiving no BZDs and seven MTLE patients receiving BZDs. BZDR densities in brain sections were measured by using [(125)I]iomazenil autoradiography. Cell densities were measured from cresyl violet-stained sections. RESULTS: Compared with non-MTLE patients, non-BZD-treated MTLE patients showed remarkable reduction of BZDR density in the pyramidal cell region of cornu ammonis (CA) 1, CA3, and CA4, and a smaller but significant reduction in CA2 and the molecular and granule cell layers of dentate gyrus (mDG). In the MTLE group, the BZDR density in the mDG correlated with that in lateral cortex. Significant correlations between BZDR density and cell density were found in all hippocampal regions. A significant difference in BZDR density/cell-density ratio was observed in CA1 region between MTLE and non-MTLE. BZD-treated patients tended to have lower BZDR densities than did non-BZD-treated patients, although the differences did not reach significance. In all MTLE cases, [(123)I]iomazenil singlephoton emission computed tomography (SPECT) showed decreased BZDR binding in MTL. CONCLUSIONS: In MTLE, BZDR densities decreased parallel to reduction in cell density in most hippocampal subfields, but BZDR density appeared to decrease in excess of neuron loss in CA1. [(125)I]iomazenil SPECT might be useful for detecting in vivo changes of BZDR density.

Adolescent↗

PubMedDate not supplied

Vaccination and infection as causative factors in Japanese patients with Rasmussen syndrome: molecular mimicry and HLA class I.

Rasmussen syndrome is an intractable epilepsy with a putative causal relation with cellular and humoral autoimmunity. Almost half of the patients have some preceding causative factors, with infections found in 38.2%, vaccinations in 5.9% and head trauma in 8.9% of Japanese patients. In a patient with seizure onset after influenza A infections, cross-reaction of the patient's lymphocytes with GluR epsilon 2 and influenza vaccine components was demonstrated by lymphocyte stimulation test. Database analyses revealed that influenza A virus hemagglutinin and GluR epsilon 2 molecules contain peptides with the patient's HLA class I binding motif (HLA - A*0201). The relative risks of HLA class I genotypes for Rasmussen syndrome are 6.1 (A*2402), 6.4 (A*0201), 6.3 (A*2601) and 11.4 (B*4601). The relative risks of HLA class I-A and B haplotypes are infinity (A*2601 + B*5401), 21.1 (A*2402 + B*1501), 13.3 (A*2402 + B*4801) and 5.1 (A*2402 + B*5201). Some alleles and haplotypes of HLA class I may be the risk factors in Japanese patients. Cross-reactivity of cytotoxic T lymphocytes may contribute to the processes leading from infection to the involvement of CNS.

Encephalitis↗