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Katsuhiro Kobayashi

Publications and source records attributed to Katsuhiro Kobayashi.

At least 19 recordsLinked to original sources
PubMed2006

Hepatic artery chemoembolization for 110 gastrointestinal stromal tumors: response, survival, and prognostic factors.

BACKGROUND: The efficacy of hepatic artery chemoembolization (HACE) was evaluated for gastrointestinal stromal tumors (GISTs) metastatic to the liver. METHODS: Records for patients with metastatic GIST who underwent HACE between January 1993 and March 2005 were reviewed and cross-sectional images were used to determine objective tumor response. Progression-free survival in the liver (PFS-liver) and overall survival (OS) were calculated with the Kaplan-Meier method. Patient, tumor, and treatment variables were analyzed to identify factors influencing survival. RESULTS: Of the 110 patients identified, the radiologic response to HACE could be evaluated in 85 patients, 12 of whom (14%) demonstrated partial responses, 63 of whom (74%) demonstrated stable disease, and 10 of whom (12%) demonstrated progressive disease. PFS-liver rates were 31.2%, 8.2%, and 5.4% at 1, 2, and 3 years, respectively; the median PFS time was 8.2 months. OS rates were 62% at 1 year, 32% at 2 years, and 20% at 3 years; the median OS time was 17.2 months. Patients who had >5 liver metastases and received only 1 HACE treatment were found to have a shorter PFS compared with patients with fewer metastases or those who received > or =2 HACE sessions. Extensive liver involvement, the presence of extrahepatic metastases, and progression of liver disease after HACE were associated with poor OS. Use of imatinib prolonged OS time. CONCLUSIONS: HACE produced a durable tumor response or disease stabilization in the majority of patients with GISTs metastatic to liver. Extent of liver disease, presence of extrahepatic disease, number of embolization treatments, and use of imatinib were found to have prognostic influence on PFS, OS, or both.

Adult↗
PubMed2006

A population-based survey of childhood epilepsy in Okayama Prefecture, Japan: reclassification by a newly proposed diagnostic scheme of epilepsies in 2001.

The purpose of this study is to clarify the usefulness and problems of the newly proposed classification of epilepsies (International League Against Epilepsy: ILAE, 2001) in the epidemiological studies of epilepsy. We previously conducted an epidemiological study in Okayama Prefecture, Japan, in 1999, using the ILAE 1989 classification. Among 250,997 children under 13 years of age, 2220 epileptic patients were ascertained. In this study, we reclassified them according to the ILAE 2001 classification, focusing on axes 2 (seizure types) and 3 (syndromes). We were able to classify 1803 (95.0%) seizure types out of 1899 with detailed clinical information. In focal seizures, the most common were secondarily generalized seizures (88.6%), which generally do not represent a unique anatomic substrate. In generalized seizures, topic-clonic seizures (40.7%) and spasms (21.0%) were the most common. We identified only 269 (12.1%) patients with specific epilepsy syndromes out of the 2220. We classified 1761 patients without specific syndromic diagnoses only by axis 2, but the new concept of epileptic seizure types, representing a unique pathophysiologic mechanism and anatomic substrate, was not very meaningful in most cases, even in those with focal seizures.

Child↗
PubMed2006

Diagnostic issues and treatment of cryptogenic or symptomatic generalized epilepsies.

To clarify the diagnostic issues and treatment of patients with cryptogenic or symptomatic generalized epilepsies, not including West syndrome (WS), we investigated electroclinical change during the clinical course, and treatment effects in these patients. The selection criteria were minor generalized seizures as their main seizure type and diffuse epileptic discharges as their main EEG findings. Regarding EEG, we included EEGs that predominantly displayed multifocal spike-waves because of the inclusion of severe epilepsy with multiple independent spike foci (SE-MISF). We divided the subjects into two groups according to their main seizure types: Group A (54 patients) with brief tonic seizures and Group B (24 patients) with myoclonic seizures and/or atypical absences. The main epileptic syndromes were considered to be Lennox-Gastaut syndrome and SE-MISF in Group A, and epilepsy with myoclonic-astatic seizures in Group B. A history of WS was often seen in Group A, but it was exceptional in Group B. During the clinical course, seizure types did not basically change in Group A. EEG patterns were changeable in both groups. Although there was some overlap in electroclinical manifestations among epileptic syndromes, a transition between the two groups was not seen. High-dose valproate and ethosuximide were the most effective in Groups A and B, respectively. Long-term prognosis was significantly more favorable in Group B than in Group A.

Adolescent↗
PubMed2006

Treatment of epilepsy with electrical status epilepticus during slow sleep and its related disorders.

To elucidate an effective therapeutic strategy for 'ESES syndrome', epilepsy with electrical status epilepticus during slow sleep (ESES) and its related epileptic disorders, we studied the effect of treatment on the EEG pattern of continuous spike-waves during slow wave sleep (CSWS) in 15 afflicted patients. Basically performed in the following order, the employed therapies included (1) high-dose valproate (VPA) therapy (serum level >100 microg/ml); (2) a combination therapy of VPA and ethosuximide (ESM); (3) short cycles of high-dose diazepam (oral or intrarectal DZP, 0.5-1 mg/kg per day for 6-7 days); and (4) intramuscular synthetic ACTH-Z therapy (0.01-0.04 mg/kg per day for 11-43 days). Regarding the initial EEG effect, a remission of CSWS was achieved by high-dose VPA therapy in 7 of 15 trials (47%), by the combination therapy of VPA and ESM in 3/7 trials (43%), by short cycles of high-dose DZP in 2/4 trials (50%), and by ACTH-Z therapy in 2/5 trials (40%). A permanent remission of ESES syndrome was achieved by high-dose VPA therapy and/or combination therapy of VPA and ESM in 10 patients (67%). The effects of short cycles of high-dose DZP and ACTH-Z therapy were at best temporary. Our strategy for the treatment of ESES syndrome is therefore considered valid.

Adolescent↗
PubMed2006

Prevalence of childhood epilepsy and distribution of epileptic syndromes: a population-based survey in Okayama, Japan.

PURPOSE: A population-based survey childhood epilepsy was undertaken in Okayama Prefecture, Japan, to determine the prevalence rate and the distribution of epilepsies and epileptic syndromes according to the International Classification (ILAE, 1989). METHODS: Information on patients younger than 13 years with active epilepsy was collected from medical records. Patients diagnosed with epilepsy according to clinical and EEG findings were put on the list even if those patients had had a single seizure or seizures occurring during febrile episodes. RESULTS: In total, 2,220 cases were identified from a background population of 250,997. The prevalence rate was 8.8 per 1,000. If we exclude patients who had experienced a single seizure or seizures occurring during febrile episodes to compare our results with previous reports, the prevalence rate was 5.3 per 1,000. Of the 2,220 cases, 2,030 (91.4%) were classified into three major categories by ILAE classification. They consisted of 1,556 (76.7%) with localization-related epilepsy, 453 (22.3%) with generalized epilepsy, and 21 (1.0%) with undetermined epilepsy. Of the 2,030 cases, 309 (15.2%) were classified into epileptic syndrome categories, and 84.8% of the total were nonspecific types of epilepsy. CONCLUSIONS: The prevalence rate of childhood epilepsy was distributed from 5.3 to 8.8 per 1,000. The appearance rate of various types of epileptic syndromes was low. Most cases could not be classified into the detailed categories of the International Classification (ILAE, 1989).

Age Factors↗
PubMed2006

EEG dipole characteristics in Panayiotopoulos syndrome.

PURPOSE: Panayiotopoulos syndrome (PS) is a type of benign childhood partial epilepsy that is frequently associated with abundant multifocal spikes other than main occipital spikes on the EEG. In this study, we investigated the characteristic features of dipoles in PS. METHODS: We performed dipole analysis of the interictal occipital spike discharges seen in 10 children with PS (group A) and in 10 children with other types of symptomatic localization-related epilepsy (group B). We analyzed the dipoles of the averaged spike in each patient. RESULTS: In group A, the averaged occipital spikes in each patient showed dense dipole locations in the mesial occipital area; in group B, widely scattered dipole locations were observed. In Group A, the geometric centers of the dipoles at each time point (such as at the main negative peak and before or after the main peak) were estimated in the neighboring locations. In contrast, they tended to be scattered in group B. CONCLUSIONS: Our study reveals that PS has high dipole stability, similar to that of rolandic epilepsy. From the electroencephalographic view, this seems to indicate a close link between these two syndromes.

Adolescent↗
PubMed2005

Relationship between severity of epilepsy and developmental outcome in Angelman syndrome.

To clarify the relationship between the degree of developmental disturbance and the severity of epilepsy in Angelman syndrome, we investigated 11 patients and measured both clinical outcomes and EEG parameters. Seven patients were followed up until after 8 years of age. Eight patients were found to have 15q11-q13 deletions. All patients experienced epileptic seizures and all but one displayed non-convulsive status epilepticus (NCSE) during the period of observation. Epileptic seizures, including NCSE, disappeared by around 8 years of age. In addition, specific epileptic discharges, as measured by EEG, tended to subside with age. Although development seemed almost normal or only slightly delayed during the first 6 months of life, all patients eventually developed severe retardation. Two patients displayed very severe retardation and were unable to comprehend language or walk independently at the last follow-up. Only one patient was able to speak a few meaningful words. In one of the most severely affected patients, who showed the earliest onset of seizures and NCSE, it is possible that the repetitive bouts of NCSE might be responsible for the severe developmental outcome. However, the other patient with particularly severe retardation did not experience NCSE, while the patient with the most favorable outcome had repetitive episodes of NCSE. Therefore, we conclude that the severity of developmental disturbance in Angelman syndrome is not necessarily related to the degree of epilepsy. However, intensive therapy for NCSE might still be justified because there are some patients in whom NCSE results in a transient and sometimes permanent decline in mental and motor functioning.

Adolescent↗
PubMed2005

Dipole modeling of epileptic spikes can be accurate or misleading.

PURPOSE: We investigated the accuracy and potential for serious error when representing cortical generators of epileptic spikes with the common single-dipole model. Spike generators were realistically simulated with cortical areas of different extents. METHODS: The source was simulated by using a patch that comprised small triangles on the cortical surface, each triangle having an elementary dipole generator with a moment corresponding to real intracerebral fields of spikes. The source-patch covered various clinically important parts of the temporal and frontal lobes, with an area ranging from 6 to 120 cm2. The scalp field was computed for each source-patch by using a realistic head model and was fitted by the single-dipole model to determine the best-fit dipole and the intracerebral distribution of residual variance (RV). Dipole modeling also was performed for the simulated scalp field with additional real EEG background. RESULTS: The RV after fitting a dipole to the scalp field without noise was at most 1.34%. Scalp spikes arising from sources of 6 cm2 were of small amplitude, and the dipoles estimated for these spikes were inconsistent. Extension of the source area was associated with increase of scalp potential amplitude, only very small increase of RV, and increased consistency of the estimated dipoles. When the source was very large, the dipoles clustered at very misleading locations. CONCLUSIONS: Pitfalls in dipole source localization are caused by the procedure of fitting the simplistic dipole model to real cortical sources with spatial extent and complex configuration.

Action Potentials↗
PubMed2005

Characteristics of slow waves on EEG associated with epileptic spasms.

PURPOSE: The high-voltage slow waves (HVSs) on EEG associated with epileptic spasms were investigated to clarify their characteristics and their relation to the pathophysiology of spasms in West syndrome and related disorders. METHODS: In 14 patients, digitally recorded EEG segments showing the ictal HVSs were extracted and their traces were overlaid by using an average reference. The ictal HVSs were also averaged to build maps for investigation of the pattern of potential distribution over the scalp. RESULTS: In a total of 685 recorded spasms, 346 (50.5%) with minimal artifacts were selected to demonstrate that the ictal HVSs had a largely consistent waveform and distribution in each patient. The ictal HVSs were symmetrical in 10 patients and asymmetrical in the other four, and were relatively negative over the posterior region and positive over the frontal or temporal regions in 11 patients. Two symptomatic patients showed a marked deviation of the distribution of HVSs to the pathologically more involved hemisphere. An infant with Aicardi syndrome had two different types of spasms, each type showing a consistent pattern of HVSs with a lateralized distribution. CONCLUSIONS: The patterns of distribution of the ictal HVS may be related to the abnormal activation of the brain in the generation of spasms.

Brain↗
PubMed2004

Kinesigenic attacks with ictal electroencephalographic abnormalities.

We report on a 14-year 5-month-old male who had attacks similar to those of paroxysmal kinesigenic choreoathetosis. The attacks were elicited exclusively by sudden movements. On several occasions, these attacks were immediately followed by loss of consciousness or a seizure. Ictal electroencephalograms of his attacks without loss of consciousness or a seizure indicated 1.5-3.0 Hz activity in the left hemisphere. A small dosage of carbamazepine was remarkably effective in stopping the attacks. This case demonstrates that a thorough ictal electroencephalographic examination is indispensable for clarifying the pathophysiology of kinesigenic attacks. The relationship between paroxysmal kinesigenic choreoathetosis and supplementary motor area seizures is also discussed.

Adolescent↗
PubMed2004

A study of spike-density on EEG in West syndrome.

To elucidate the pathophysiology of spasms in series, the distribution and density of spikes on hypsarrhythmia were studied in 13 patients with West syndrome by excluding slow waves from EEG using a digital filter. (1) Interictal spikes were mostly multifocal and dominant over the bilateral posterior head area with very few diffuse discharges. Therefore, spikes on hypsarrhythmia were demonstrated to occur actually depending on the brain regions although they appeared random. (2) The dominant region of interictal spikes did not correspond to the underlying focal cortical lesion in many patients, and was indicated to reflect the general process of cerebral maturation in infancy. (3) There were far fewer inter-spasm spikes, especially during the middle phase of a series of spasms, than interictal spikes. It was implied that the cortical activity of hypsarrhythmia was interfered with by the abnormal subcortical function, which might be related to the generation of spasms. (4) The dominant region of inter-spasm spikes tended to coincide with a focal cortical lesion shown by MRI and the focus of associated partial seizures.

Action Potentials↗
PubMed2004

Clinical and electroencephalographic characteristics of children with febrile seizures plus.

OBJECTIVES: Febrile seizures plus (FS+) are attracting attention for their corresponding genetic abnormalities, and are defined as febrile seizures (FS) continuing beyond 6 years of age (late FS) or those associated with afebrile seizures. We tried to elucidate their clinical and EEG characteristics as compared with those of children having only FS. SUBJECTS AND METHODS: We reviewed clinical records in a pediatric neurology clinic to identify 31 patients with FS+ (group FS+) and 51 with only FS (group FS). Their family history of seizures, clinical features and EEG findings were compared. RESULTS: A family history of seizures was noted in 14 patients (45.2%) of group FS+ and in 24 (47.1%) of group FS. In group FS+, 19 patients had late FS, 11 had afebrile seizures, and the remaining one had both types of seizures. Two patients had seizures induced by TV/video-game as well, and another suffered from absences. Epileptic EEG abnormalities, which included diffuse spike-waves and focal spikes, were noted in 13 patients (41.9%) of group FS+ and 12 (23.5%) of group FS. CONCLUSIONS: The clinical and EEG characteristics of the children having FS+ were diverse, without significant differences from those with FS except for the seizures types.

Adolescent↗
PubMed2004

Very fast rhythmic activity on scalp EEG associated with epileptic spasms.

PURPOSE: Very fast activity was investigated on the ictal EEGs of epileptic spasms to elucidate the pathophysiology of West syndrome (WS) and related disorders from a novel point of view. METHODS: The traces of scalp ictal EEG of spasms temporally were expanded in 11 patients whose clinical diagnosis was symptomatic WS in six, cryptogenic WS in two, Aicardi syndrome in one, and symptomatic generalized epilepsy after WS in the remaining two. Time evolution of averaged power spectra of the ictal fast activity also was analyzed in each patient. RESULTS: Rhythmic gamma activity with frequency ranging from 50 to 100 Hz was detected in a total of 345 of 537 spasms. Fast activity was seen bilaterally in nine patients, was lateralized to one hemisphere in another, and appeared independently on each hemisphere in the remaining infant with Aicardi syndrome. Power spectra showed a clear peak corresponding to spasm-associated gamma rhythm, with frequency centering approximately 65 Hz and ranging from 51 to 98 Hz. The morphology and spectral characteristics of ictal gamma rhythm were completely different from those of muscle activity or alternating current (AC) artifacts. CONCLUSIONS: Spasm-associated gamma activity was clearly detected on the scalp. This observation may provide a clue to the pathophysiology of spasms.

Cerebral Cortex↗
PubMed2004

Initiation of treatment and selection of antiepileptic drugs in childhood epilepsy.

PURPOSE: A retrospective study was carried out on 53 cases with childhood epilepsy to evaluate the validity of the initial selection of antiepileptic drug (AED). METHODS: We investigated the AEDs selected at the beginning of the treatment from the medical records of 53 untreated cases. A follow-up study was undertaken to evaluate the effects of the AEDs. In the second study, we investigated the AEDs of 10 cases with atypical benign partial epilepsy (ABPE), to clarify whether the initial AEDs selected for rolandic epilepsy were related to the appearance of ABPE. RESULTS: The AEDs used at the initial stage consisted of carbamazepine (CBZ), valproic acid (VPA), phenobarbital (PB), and vitamin B6. The main AEDs were CBZ and VPA for localization-related epilepsy, and VPA for generalized epilepsy. The initial selection of AEDs in 41 (85.4%) of 48 cases treated with AEDs were considered to be correct from the results of follow-up. We could not specify any AEDs that related to the appearance of ABPE. CONCLUSIONS: The selection of AED in this series was considered to be most appropriate. We proposed a criterion to determine whether to begin the AED treatment immediately at the initial seizure.

Adolescent↗
PubMed2003

A simulation study of the error in dipole source localization for EEG spikes with a realistic head model.

OBJECTIVE: We tried to determine the error range of dipole modeling for EEG spikes originating from various clinically important sources by a simulation study employing a realistic head model. The computed error range was also compared with the degree of disturbance of dipole modeling caused by adding background activity to the spike. METHODS: The scalp fields generated by temporal, frontal and rolandic epileptic sources with spatial extent were simulated, and the corresponding 3-dimensional maps of residual variance (RV) were built by computing the RV for a single dipole at each point on a fine imaginary grid in the brain. Single dipole modeling was also performed for the simulated scalp fields after adding real background activity. RESULTS: The brain volume corresponding to a small RV was compact for the frontal sources and the lateral and baso-mesial temporal sources, and large for the anterior and baso-lateral temporal sources. The distribution of dipoles estimated for spikes contaminated with background corresponded to that of the volume of small RV and to spike-amplitude. Estimates were improved by employing inferior temporal electrodes. CONCLUSIONS: When evaluating dipole models of epileptic spikes, error ranges can be estimated and they vary considerably from region to region. SIGNIFICANCE: This study illustrates the variability of the error in dipole modeling of epileptic spikes. This variability is important when considering the clinical interpretation of modeling results.

Brain Mapping↗
PubMed2003

In situ observation of the four-step dehydration process of the 1 beta-methylcarbapenem antibiotic CS-834 crystal by X-rays.

The 1 beta-methylcarbapenem antibiotic CS-834 takes six crystalline forms depending on ambient conditions. The X-ray powder diffraction revealed that the dihydrate crystal (B2-form) was changed to the monohydrate (B1-form) through the intermediate form (B2'-form). The monohydrate form was then changed to the dehydrate (B0-form) through the intermediate B1'-form. The progress of the dehydration along the needle axis (c-axis) was observed under a microscope. When a single crystal of the B2-form was mounted on a diffractometer and the humidity was reduced, the crystal was gradually changed to the various dehydration forms with retention of the single crystal. The crystals of B2- to B0-forms form isostructures to each other except the solvent water molecules. In the crystal structure of the B1-form, the pivaloyloxymethyl moiety is disordered. One is nearly similar to that of the B2-form, while another is similar to that of the B0-form. Each crystal structure consists of a columnar arrangement of CS-834 along the c-axis, and the water molecules are located between the columns and form a characteristic hydrogen bond network. When the water molecules leave the crystal, the columns slide slightly following the slight conformational change in the pivaloyloxymethyl groups and are connected by another type of hydrogen bond network. Such a rearrangement of the hydrogen bond network should be a motive force of the phase change to the next step due to the dehydration. Since the hydrogen bond network extends along the c-axis, the dehydration proceeds along the c-axis as observed microscopically.

Anti-Bacterial Agents↗
PubMed2003

Physicochemical and crystal structure analyses of the antidiabetic agent troglitazone.

The antidiabetic agent troglitazone has two asymmetric carbons located at the chroman ring and the thiazolidine ring and is produced as a mixture of equal amounts of four optical isomers, 2R-5S, 2S-5R, 2R-5R, and 2S-5S. The crystalline powdered drug substance consists of two diastereomer pairs, 2R-5R/2S-5S and 2R-5S/2S-5R. There are many types of crystals obtained from various crystallization conditions. The X-ray structure analysis and the physicochemical analyses of troglitazone were performed. The solvated crystals of the 2R-5R/2S-5S pair were crystallized from several solutions: methanol, ethanol, acetonitrile, and dichloromethane. The ratio of solvent and troglitazone was 1 : 2 (L1/2-form). The monohydrate crystals were obtained from aqueous acetone solution (L1-form). On the other hand, only an anhydrate crystal of the 2R-5S/2S-5R pair was crystallized from various solutions (H0-form). The dihydrous mixed crystal (MA2-form) was obtained from a mixture of the two diastereomer pairs of 2R-5R/2S-5S and 2R-5S/2S-5R in equal amounts by the slow evaporation of aqueous acetone solution. The crystal structure of the MA2-form is similar to the H0-form. When the MA2 crystal was kept under low humidity, it was converted into the dehydrated form (MA0-form) with retention of the single crystal form. The structure of the MA0-form is isomorphous to the H0-form. The MA2-form was converted into the MA0-form and vice versa with retention of the single crystal under low and high humidity, respectively. The crystallization and storage conditions of the drug substances were successfully analyzed.

Chemical Phenomena↗