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H Otsubo

Publications and source records attributed to H Otsubo.

At least 37 records · Page 2Linked to original sources
PubMed2001

Comparison of electroencephalographic dipoles of interictal spikes from prolonged scalp video-electroencephalography and magnetoencephalographic dipoles from short-term recording in children with extratemporal lobe epilepsy.

We retrospectively compared electroencephalographic (EEG) dipoles of interictal spikes from prolonged video-EEG monitoring with magnetoencephalographic dipoles from short-term recording in four children with extratemporal lobe epilepsy. We analyzed both sets of dipoles using individual interictal spikes and single moving dipole modeling and evaluated the profiles of spike appearance, dipole position, and orientation in EEG and magnetoencephalography. We obtained more than 100 magnetoencephalographic spikes in two patients who manifested frequent interictal EEG spikes throughout both day and night but fewer than 40 magnetoencephalographic spikes in two patients who had interictal EEG spikes mainly during sleep. The dipole positions of EEG and magnetoencephalography were in close proximity and included in the surgical resection area. Most of the dipoles between EEG and magnetoencephalography were oriented perpendicularly. A combination of EEG dipole analysis from prolonged video-EEG monitoring and magnetoencephalographic dipole analysis provides complementary information for presurgical evaluation in children with intractable extratemporal lobe epilepsy.

Adolescent↗
PubMed2001

Computerized brain-surface voltage topographic mapping for localization of intracranial spikes from electrocorticography. Technical note.

The purpose of this paper is to describe the use of computerized brain-surface voltage topographic mapping to localize and identify epileptic discharges recorded on electrocorticographic (ECoG) studies in which a subdural grid was used during intracranial video electroencephalographic (IVEEG) monitoring. The authors studied 12 children who underwent surgery for intractable extrahippocampal epilepsy. Cortical surfaces and subdural grid electrodes were photographed during the initial surgery to create an electrode map that could be superimposed onto a picture of the brain surface. Spikes were selected from ictal discharges recorded at the beginning of clinically confirmed seizures and from interictal discharges seen on ECoG studies during IVEEG recording. A computer program was used to calculate the sequential amplitude of the spikes by using squared interpolation, and they were then superimposed onto the electrode map. Interictal discharges and high-amplitude spike complexes at seizure onset were plotted on the map. This mapping procedure depicted the ictal zone in nine patients and the interictal zone in 12, and proved to be an accurate and useful source of information for planning corrective surgery.

Action Potentials↗
PubMed2001

[Surgical treatment of refractory childhood epilepsy with special reference to the role of pediatric neurologists: introductory remarks].

There are many differences between children and adult patients regarding the selection of candidates for epilepsy surgery, decision about the timing of surgery, pre- and intra-surgical evaluation and follow-up. A comprehensive approach by an epilepsy surgery team consisting of pediatric neurologists, neurosurgeons and other medical staffs is absolutely necessary for successful surgical treatment of refractory childhood epilepsy and the improvement of the patient's quality of life. The potential risks and benefits of the surgery must be carefully weighed for each child from various aspects. Pediatric neurologists should make a more active contribution to this whole process.

Child↗
PubMed2001

[Pre- and intra-operative evaluation of epileptic children with intractable seizure disorders: the hospital for sick children].

The pediatric epilepsy management team in the Hospital for Sick Children, Toronto, Canada, consists of neurologists, neurophysiologists, neurosurgeons, neuropyschologists, clinical nurse specialist/nurse practitioners, social workers, EEG technologists and psychiatrists. The patients are initially referred to us for the diagnosis of seizure disorders. Epileptic foci and eloquent cortices are identified by neurophysiological studies such as EEG, MEG and SEP. Epileptogenic lesions can be visualized by MRI, the language, motor and sensory cortices by fMRI and the regions of hypoperfusion and hypometabolism in the epileptic foci, by SPECT and PET, respectively. The results of these studies are then discussed by members of the team. For patients with lesional epilepsy, an intraoperative image guided system and intraoperative electrocorticography are used, when lesionectomy, lobectomy and additional multiple subpial transection (MST) are performed. Patients without an identifiable lesion require intracranial invasive video EEG using subdural grids or depth electrodes, which are constructed based on MEG spike sources, seizure semiology and scalp video EEG. After the identification of the epileptogenic and functional zones, maximum cortical excision and MST are performed to control seizures and to minimize functional deficits. Pediatric neurologists should assess the intractability of epilepsy, identify the epileptogenic zone, determine the excisable epileptic region, and minimize postoperative side effects, thereby leading the epilepsy management team.

Brain↗
PubMed2001

Surgery for intractable epilepsy in a 14-year-old girl.

We report on a 14-year-old girl who presented with a 2-year history of simple and complex partial seizures with secondary generalisation. Monotherapy using carbamazepine and combination therapy using carbamazepine and gabapentin had been tried within the 2 years before presentation. Seizure control, however, was poor. Magnetic resonance imaging showed structural abnormalities over the right occipital and temporal lobes. Continuous scalp video electroencephalography was performed over 4 days, during which six clinical seizures were associated with electroencephalography changes at the right occipital and temporal lobes. Invasive intracranial video electroencephalography identified a focus at the right occipital lobe, a focus at the right temporal lobe that spread rapidly to the right parietal lobe, and an irritative zone over the posterior part of the right frontal lobe. Functional mapping delineated the motor and sensory cortices. Right temporal lobectomy, right occipitoparietal cortical excision, and multiple subpial transections of the posterior part of the right frontal lobe were performed. For 16 months after the surgery, the patient has been seizure-free while receiving drug treatment, and the only complication reported has been a segmental loss of the left visual field.

Adolescent↗
PubMed2000

Systematic approach to dipole localization of interictal EEG spikes in children with extratemporal lobe epilepsies.

OBJECTIVES: To assess the reliability of dipole localization based on residual variances (RV), using equivalent current dipole analysis of interictal EEG spikes in children with extratemporal lobe epilepsy. METHODS: Four pediatric patients with extratemporal lobe epilepsy were studied. Digital EEG was recorded from 19 scalp electrodes. Computer programs for spike detection and clustering analysis were used to select spikes. Dipoles were calculated 5 times for each spike using different initial guesses by the moving dipole model. Standard deviation (SD) of the dipole positions was calculated at each time point in the 5 trials. RESULTS: We analyzed the dipoles at 1097 time points from 4 patients. Among 106 time points with RV < 2%, the SD was < 1 mm in 78 (74%), while in those with SD > 1 mm the dipole positions varied between 2.8 and 52.6 mm. Of dipoles with RV < 1%, 26 of 27 (96%) had an SD < 1 mm; the one dipole with SD > 1 mm varied within 2.5 mm. The dipole localizations with RV < 2% corresponded to the epileptogenic zones identified on intracranial invasive video EEG and intraoperative ECoG. CONCLUSIONS: The systematic approach of equivalent current dipole analysis using spike detection, clustering analysis, and an RV < 2% as a standard is useful for identifying extratemporal epileptic regions.

Adolescent↗
PubMed2000

[Flowcytomeric analysis on neutrophil intracellular enzyme activity in patients on hemodialysis and continuous ambulatory peritoneal dialysis].

To elucidate the mechanism of neutrophil dysfunction in patients with maintenance hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD), intracellular enzyme activity such as oxidative burst, elastase, cathepsin, and collagenase, was investigated. Response of enzyme activity to in vitro addition of TNF-alpha, which is known to have a powerful priming effect on neutrophils, was also evaluated. Peripheral blood from 15 HD and 15 CAPD patients was washed and incubated with Cell Probe, an indicator for intracellular enzyme activity. Mean fluorescent intensity of neutrophils, which represents neutrophil enzyme activity, was measured by flowcytometry. In HD group, unstimulated enzyme activity was similar to that of control, but activity after addition of TNF-alpha was significantly lower than the control. In the group of CAPD, enzyme activity without stimulation was not different from that of control, and in TNF-alpha stimulated neutrophils, only elastase activity was lower than control. Many of the enzyme activities after stimulation were lower in HD than in CAPD. Response to in vitro addition of TNF-alpha was diminished in both dialysis groups, but more prominent in HD neutrophils. Duration of dialysis, serum concentration of beta 2-microglobulin (beta 2-MG) and parathyroid hormone (PTH) was significantly related inversely to intracellular enzyme activity in HD patients. To the contrary, in CAPD group, although beta 2-MG and PTH showed similar negative correlation, duration of dialysis was not related to enzyme activity. These results indicate that neutrophils in patients with maintenance dialysis have diminished intracellular oxidative burst, elastase, and cathepsin activity. Especially, impaired response to TNF-alpha closely related to neutrophil dysfunction in dialysis patients.

Adult↗
PubMed2000

Magnetoencephalography in children with Landau-Kleffner syndrome and acquired epileptic aphasia.

BACKGROUND AND PURPOSE: Landau-Kleffner syndrome (LKS) is epileptiform aphasia acquired during childhood and occurring in children with previously normal language development. The epileptiform activity in these children is thought to result in a functional ablation of eloquent speech areas. The purpose of this study was to investigate the usefulness of magnetoencephalography (MEG) for localizing the source of epileptiform activity in these patients. METHODS: Nineteen patients with acquired aphasia and a suspected diagnosis of LKS were referred for MEG evaluation. Patients ranged in age from 4 to 14 years. Fourteen MEG studies were performed on a 74-channel system, four on a 148-channel whole-head system, and one on a 37-channel system. RESULTS: Thirteen of the 19 patients had perisylvian MEG spikes. In 10 of the patients, the spikes were bilateral, and in three they were unilateral. Four other patients had non-sylvian spikes, and two patients had no spikes recorded. The results of MR imaging were normal or noncontributory for all 19 patients. CONCLUSIONS: MEG can play a useful role in evaluating children with LKS and acquired epileptiform aphasia, both in diagnosis and in aiding presurgical localization of epileptiform activity when surgery is being considered.

Adolescent↗
PubMed2000

Severe aplastic anemia associated with chronic natural killer cell lymphocytosis.

Chronic natural killer (NK) lymphocytosis involves a persistent increase in CD56+ large granular lymphocytes (LGLs) that is sometimes associated with immune-mediated complications, such as anemia and neutropenia. However, aplastic anemia (AA) is a rare complication. Here we describe 2 patients with severe AA who presented with persistent increases in NK cells. Their LGLs were positive for CD56, CD16, and intracellular interferon (IFN)-gamma but negative for CD3, Fas-ligand, and T-cell receptor rearrangement, findings that are compatible with NK cells. Not only the number of NK cells, but NK activity as well, was increased in both patients. The number of NK cells changed according to hematologic recovery and relapse in 1 case. Thus, there seemed to be a close relationship between NK cells and the progression of AA, at least in this instance. Further investigation of the clinical course of similar cases and the characteristics of NK cells is necessary.

Aged↗
PubMed1999

Magnetoencephalographic localization in pediatric epilepsy surgery: comparison with invasive intracranial electroencephalography.

The object of this study was to determine the concordance of the anatomical location of interictal magnetoencephalographic (MEG) spike foci with the location of ictal onset zones identified by invasive ictal intracranial electroencephalographic recordings in children undergoing evaluation for epilepsy surgery. MEG was performed in 11 children with intractable, nonlesional, extratemporal, localization-related epilepsy. Subsequently, chronic invasive intracranial electroencephalographic monitoring was performed by using subdural electrodes to localize the ictal onset zone and eloquent cortex. Based on the invasive monitoring data, all children had excision of, or multiple subpial transections through, ictal onset cortex and surrounding irritative zones. In 10 of 11 patients, the anatomical location of the epileptiform discharges as determined by MEG corresponded to the ictal onset zone established by ictal intracranial recordings. In all children, the anatomical location of the somatosensory hand area, determined by functional mapping through the subdural electrode array, was the same as that delineated by MEG. Nine of 11 patients became either seizure-free or had a greater than 90% reduction in seizures after surgery, with a mean follow-up of 24 months. MEG is a powerful and accurate tool in the presurgical evaluation of children with refractory nonlesional extratemporal epilepsy.

Adolescent↗
PubMed1999

Interhemispheric interactions analyzed by coherence during flexor spasms.

OBJECTIVE: We used coherence analysis to test for leading discharges on an ipsilateral right mesial temporal lesion in a 5 year old boy with flexor spasms. METHOD: Digital EEG analysis with video-EEG telemetry was performed preparatory to epilepsy surgery. RESULTS: Study of 10 spasms with head drop and subsequent flexion of both arms demonstrated an interhemispheric time lag with secondary bilateral synchrony, with a mean difference of 17 ms. The right hemisphere led. After a lesionectomy with resection of epileptic regions (performed with electrocorticographical guidance), the patient has been seizure-free for 4 years. Pathology confirmed a low-grade mixed glioma and cortical dysgenesis. CONCLUSION: The coherence analysis demonstrated a pathway of secondary generalization, confirming that the lesional side was leading during ictal generalized discharges in flexor spasms.

Brain↗
PubMed1999

Utility of digital camera-derived intraoperative images in the planning of epilepsy surgery for children.

OBJECTIVE: This study was undertaken to assess the utility of digital camera-derived intraoperative images in the planning of neurosurgery for children with epilepsy. METHODS: A hand-held digital camera was used to capture the exposed surgical field at the time of craniotomy for 11 children with medically intractable seizure disorders. Intraoperative somatosensory evoked potential recordings of phase reversals and direct cortical stimulation were used to map areas of eloquent brain tissue. Digital camera images were obtained to mark regions of functional brain tissue with respect to cortical surface landmarks and subdural grid placement. The digital camera images were then immediately downloaded, in the operating room, to a laptop computer, which was placed next to the electroencephalographic recording device. Using computer software, the epileptologist highlighted the primary and secondary zones of epileptogenesis, as well as the functional brain areas identified during the monitoring period, on the digital camera images on the computer screen. A neurosurgical map was thus created to aid the neurosurgeon and the epileptologist with the proposed cortical resections and multiple subpial transections. RESULTS: With the images obtained using the digital camera, the epilepsy team was able to observe the contacts of the grid electrodes with the brain during the procedure. Color printouts of the images served as references during the period of invasive monitoring. Zones of primary and secondary epileptogenesis, as well as areas of functional brain tissue, were identified and plotted on the digital camera images. Other benefits of the digital camera-derived images included the ability to accurately reposition the grids or letters marking eloquent brain tissue if they were inadvertently shifted during the procedure, the ease with which the images could be obtained and manipulated, the ability to assess postresection epileptiform activity of the surrounding brain tissue with images obtained while an electrocorticographic array was in place, the ability to provide the entire epilepsy team with updated information on the neurosurgical field while minimizing movement in the operating room, and facilitation, with neurosurgical maps, of discussions with the patients and their families concerning proposed cortical resections. CONCLUSION: Digital camera images have become essential components for the planning of cortical resections for children with intractable epilepsy at our institution. We envision widespread application of this technology to other neurosurgical fields.

Adolescent↗
PubMed1999

Outcome of epilepsy surgery in the first three years of life.

PURPOSE: We analyzed our experience over a 6-year period with early-childhood patients who had undergone epilepsy surgery, and investigated the surgical outcomes. METHOD: We reviewed the medical records of 23 children, ages 0-3 years, who underwent epilepsy surgery between 1991 and 1996. RESULTS: Twenty children had partial seizures; two had infantile spasms; and one had generalized tonic-clonic seizures at onset. The mean age at onset of seizures was 4.7 months, and the mean age at time of surgery was 15.3 months. A total of 32 operations (21 focal cortical resections and 11 hemispherectomies) was performed. Five of 12 children with seizures secondary to a neuronal migration disorder had reoperations, including three who ultimately underwent complete hemispherectomy. The pathology consisted of hemimegalencephaly in three patients, focal cortical dysplasia (FCD) in eight, tuberous sclerosis in one, Sturge-Weber syndrome (SWS) in five, infarction in two, low-grade glioma (LGG) in three, and post-herpes simplex virus encephalitis (HSE) in one. The follow-up period ranged from 1 to 6.5 years (mean, 3.2 years) from patients' last operation. The seizure outcome according to Engel's criteria was class I in 12 patients, class II in three, class III in six and class IV in two. CONCLUSIONS: Seizure outcomes after surgery were less favorable in infants with FCD than in those with SWS and LGG. Seizure outcome for the patients with hemispherectomies was excellent, compared with those who had focal cortical resections.

Age Factors↗
PubMed1999

Confirmation of two magnetoencephalographic epileptic foci by invasive monitoring from subdural electrodes in an adolescent with right frontocentral epilepsy.

PURPOSE: To report our evaluation of interictal two epileptic spike fields on magnetoencephalography (MEG) by using invasive intracranial monitoring in a patient without lesion on magnetic resonance imaging (MRI). METHODS: A 15-year-old left-handed boy with a 9-year history of refractory simple partial seizures, secondarily generalized, and a normal MRI, was studied with MEG to define magnetic spike sources, followed by invasive intracranial monitoring with subdural electrodes to delineate the epileptogenic zone and eloquent function pursuant to focal cortical excision. RESULTS: MEG demonstrated two spike foci on the right middle frontal and inferior rolandic areas adjacent to the sensory area. Ictal recordings during prolonged invasive monitoring from subdural electrodes revealed two epileptogenic zones in the same locations as those defined by MEG. Focal cortical excision was performed of each epileptogenic zone. The patient has been seizure free for 24 months without neurologic deficit. CONCLUSIONS: Magnetic source imaging is a valuable adjunct in the planning of subdural grid placement in epilepsy surgery, particularly in patients in whom conventional imaging fails to reveal a lesion.

Adolescent↗
PubMed1998

Early forms of microtubule-associated protein are strongly expressed in cortical dysplasia.

We report the enhanced expression of early forms of microtubule-associated proteins (MAPs) in cortical dysplasia in surgical resections from 17 children with intractable epilepsy. Large neurons, which represent one of the characteristic cellular features of cortical dysplasia, showed strong immunoreactivity for MAP1B, as well as the low-molecular-weight isoform of MAP2 (MAP2c). In situ hybridization with MAP1B antisense riboprobe showed markedly increased hybridization signal intensities in the large neurons, whereas neurons in the normal-appearing cortex and most of the normal-sized neurons in the dysplastic cortex had faint signals. Because MAP2c and MAP1B are early forms of MAPs, which are abundantly expressed in the developing brain and down-regulated in the adult, and are thought to be involved in neuronal outgrowth and plasticity, our results suggest that the structural remodeling of neuronal processes is activated in cortical dysplasia.

Adolescent↗
PubMed1998

Mesalazine-associated severe aplastic anemia successfully treated with antithymocyte globulin, cyclosporine and granulocyte colony-stimulating factor.

A 20-year-old male with ulcerative colitis complicated by mesalazine-associated severe aplastic anemia is described. The patient developed aplastic anemia four months after the start of mesalazine therapy. He was treated with antithymocyte globulin, cyclosporine, and granulocyte colony-stimulating factor (G-CSF) and responded well. Hematological complications of mesalazine are rare, but if bone marrow suppression is detected, immediate cessation of the drug and intensive immunosuppressive treatment with G-CSF should be considered.

Adult↗
PubMed1998

Long-term administration of G-CSF for aplastic anaemia is closely related to the early evolution of monosomy 7 MDS in adults.

There is an increasing incidence of the evolution of myelodysplastic syndrome (MDS) from aplastic anaemia (AA) with immunosuppressive treatment. In paediatric patients G-CSF is also reported to increase MDS evolution, but this process is not precisely understood in children or in adults. Therefore risk factors of MDS evolution in adults are evaluated here. Of 72 patients, five developed MDS. In 47 patients without cyclosporine (CyA) or antithymocyte globulin (ATG) therapy, only one developed MDS with trisomy 8, 242 months after diagnosis. But of 25 patients treated with either CyA or ATG, four developed monosomy 7 MDS within 3 years. Of these 25 patients, 18 were treated with G-CSF and the four patients (22.2%) who developed MDS were found in this group. The cumulative dose and the duration of G-CSF administration were significantly elevated in patients who developed MDS when compared with those who did not, 822.3 +/- 185.0 v 205.4 +/- 25.5 microg/kg (P<0.05) and 187.5 +/- 52.5 v 72.0 +/- 24.6 d (P<0.002), respectively. However these two values for CyA did not differ significantly. Statistically, treatment with CyA, G-CSF and combined G-CSF and CyA were significantly related to MDS evolution. The administration of G-CSF for more than a year was the most important factor (P=0.00). These results suggested that a close relationship exists between G-CSF and subsequent monosomy 7 MDS from AA in adults who receive immunosuppressive therapy. Long-term administration of G-CSF should be prohibited in order to prevent MDS evolution.

Adolescent↗