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Biomedical subjects

H Shibasaki

Publications and source records attributed to H Shibasaki.

At least 361 records · Page 20Linked to original sources
PubMed1985

Electrophysiological studies of myoclonus in sialidosis type 2.

Electrophysiological investigation was performed in 3 patients with beta-galactosidase and sialidase deficiencies (sialidosis type 2) in order to elucidate the underlying mechanism of intention myoclonus. It is a rare neuronal storage disease that begins in childhood with mental retardation, skeletal abnormalities, progressive myoclonus and cherry-red spots in the macula. Electrophysiological studies showed paroxysmal activities in the EEG, consistent temporal relationship between the EEG spikes and myoclonic jerks demonstrated by jerk-locked averaging, high amplitude somatosensory evoked potentials with altered wave form, and enhanced long-loop reflexes. These results suggest that there is a hyperexcitability of the cerebral cortex, which results in induction of intention myoclonus. The intention myoclonus in sialidosis type 2 is consistent with 'cortical reflex' myoclonus described in progressive myoclonic epilepsy due to various etiologies.

Adult↗
PubMed1985

Quantitative analysis of 'organization' by feature extraction of the EEG power spectrum.

Quantitative analysis of 'organization' of the background EEG activity was made by applying a new method of approximating the optimal intensity-fitting function to the EEG records of healthy college students. The parametric intensity-fitting function used in this study to approximate the power spectrum of EEG was a gaussian type function. Among the quantitative parameters obtained by the new method, the ratio of the integrated power of alpha rhythm to that of all rhythms and the standard deviation of the alpha frequency proved to be the most important organization parameters by inspecting the Pearson product-moment correlation coefficient. Next the automatic scoring of 'organization' was successfully performed by using the linear regression of those two organization parameters.

Adult↗
PubMed1985

Reinduction of experimental allergic encephalomyelitis in convalescent Lewis rats with cyclophosphamide.

Experimental allergic encephalomyelitis (EAE) in Lewis rats is an acute, monophasic autoimmune disease, and rats recovering from EAE are generally resistant to active reinduction. However, following immunosuppression with a high dose (100-200 mg/kg) of cyclophosphamide (CY), EAE was reinduced in convalescent rats, irrespective of whether or not they were rechallenged with the encephalitogenic inoculum. Reinduction of EAE was not observed in rats treated with low doses (20 mg/kg or less) of CY. A selective inhibition of suppressor cells during the convalescent stage may be responsible for the reinduction of EAE in Lewis rats.

Animals↗
PubMed1985

Pathogenesis of giant somatosensory evoked potentials in progressive myoclonic epilepsy.

Fifty-seven consecutive patients with myoclonus from various causes were studied by electrophysiological techniques. Giant somatosensory evoked potentials (SEPs) were observed almost exclusively in patients with progressive myoclonic epilepsy (PME) and diseases with similar clinical features that included lipidosis, neuronal ceroid lipofuscinosis and posthypoxic myoclonus. On the basis of combinations of the giant SEP and the myoclonus-related cortical spike demonstrated by jerk-locked averaging, myoclonus in these patients was classified into four types. In patients with 'cortical reflex' myoclonus (type I) who showed both the giant SEP and the myoclonus-related cortical spike, these two cortical activities were similar in terms of wave form, scalp topography, time relationship to either the long latency (C) reflex or myoclonus, the following cortical excitability, the effect of antimyoclonus drugs and alterations during slow wave sleep. It is therefore postulated that the giant SEP is generated, at least in part, by common physiological mechanisms to the myoclonus-related cortical spike, or that the latter may comprise a constituent of the former. In most patients with PME or allied diseases, both afferent and efferent components of the SEP are enhanced, but in some patients, only one of the two components seems to be predominantly enhanced.

Adolescent↗
PubMed1985

Cortical potentials associated with movement: a review.

Cortical potentials both preceding and following movement have been studied now for 20 years, since the advent of efficient averaging techniques. They have shed light on the physiology of movement initiation, have provided some insight into certain disease states, and may help our understanding of movement disorders in the future. The pertinent literature is reviewed.

Brain Damage, Chronic↗
PubMed1985

Cortical excitability after myoclonus: jerk-locked somatosensory evoked potentials.

Cortical excitability after myoclonus was investigated by electrically stimulating the median nerve just at the time of, or at intervals after, the onset of myoclonus and by averaging the EEG and EMG, using the myoclonus onset pulse as a trigger (jerk-locked somatosensory evoked potential technique). In a patient with "cortical reflex" myoclonus, cortical excitability was relatively enhanced for 20 msec just after the myoclonus, although it was suppressed throughout the postmyoclonus period. In a patient with Creutzfeldt-Jakob disease, cortical excitability was suppressed between periodic myoclonic jerks. In a patient with oculopalatal-somatic myoclonus, there was no change of cortical excitability in relation to myoclonus.

Adult↗
PubMed1985

Peripheral blood and CSF T-cell subsets in Japanese MS patients.

We analyzed peripheral blood and CSF T-cell subsets in Japanese patients with MS, using an OK series of monoclonal antibodies in an immunofluorescent technique. In the peripheral blood, suppressor T cells were increased, with a concomitant decrease in helper T cells, after recovery from acute exacerbation, but there was no relationship between T cells in peripheral blood and CSF. In the CSF, acute exacerbation was associated with an increase in Ia-positive cells and a decrease in T cells. CSF pleocytosis (with more than 30% of Ia-positive cells) probably indicated active disease.

Adolescent↗
PubMed1984

Mirror movement: application of movement-related cortical potentials.

In a patient with Kallmann's syndrome (hypogonadotropic hypogonadism and anosmia) manifesting mirror movement, cortical potentials associated with unilateral and bilateral simultaneous voluntary middle finger extensions were studied. Premovement negative slope, which has been shown to reflect preparatory excitation of motor cortex corresponding to the voluntary movement, was recorded bilaterally in this patient in spite of intended unilateral hand movement. It is suggested that mirror movement in this particular patient is generated by unintended excitation of the opposite motor cortex.

Adult↗
PubMed1984

Exacerbation of myasthenia gravis after removal of a thymoma having a membrane phenotype of suppressor T cells.

We describe a case of myasthenia gravis associated with a thymoma having a membrane phenotype of suppressor T cells, as defined by monoclonal antibodies. Thymectomy resulted in exacerbation of the disease, a drastic increase in serum acetylcholine receptor-antibody titer, and a decrease of the circulating suppressor T cell population. The findings indicate that the etiopathogenic relationship between the thymus and myasthenia gravis is variable and complex.

Adult↗
PubMed1984

Subcortical, thalamic and cortical somatosensory evoked potentials to median nerve stimulation.

Subcortical and cortical somatosensory evoked potentials (SEPs) to median nerve stimulation were studied in 16 normal controls, 3 patients with Parkinson's disease, and 2 patients with thalamic lesions. Multiple electrodes were placed over the scalp and cervical spines and connected with a hand electrode or Fz in grid II. Thalamic SEPs were recorded directly from the Vim nucleus in 3 patients with Parkinson's disease during the stereotaxic operation. SEPs recorded from the scalp-hand derivations were composed of 4 negative (N9, N11, N16, N18) and 3 positive potentials (P8, P10, P12), whereas, at the scalp-Fz electrode, only one negative peak was identified (N20). N18 is of higher amplitude on the parieto-occipital areas and corresponds to N20. On the other hand, N16 can be identified more clearly on the fronto-central areas at scalp-hand derivations because of intermixture with N18 on the posterior head areas and disappears at scalp-scalp derivation. This suggests that N16 represents a subcortical component that is picked up as a far-field potential at the scalp electrodes. Components preceding N16 at scalp-hand derivations are also interpreted as far-field potentials because of their short latency and wide distribution over the scalp. The peak latency of N16 is not significantly different from the major negativity recorded directly from the thalamus, whereas N18 (N20) occurs significantly later. From this we conclude that N16 is most probably generated in the thalamus with the potentials of shorter latency originating caudal to the thalamus and N18 rostral to the thalamus.

Adolescent↗
PubMed1984

Scalp topography of mechanically and electrically evoked somatosensory potentials in man.

Scalp topography of somatosensory evoked potentials following mechanical (SEPs(M)) and electrical (SEPs(E)) stimulation of the left middle finger was investigated with linked ear reference in 21 normal young adults. A small plastic ball (touch) or needle (pain) was used for the mechanical stimulation. With mechanical stimulation, at least 3 positive and 3 negative potentials (P19(M), N24(M), P29(M), N36(M), P49(M) and N61(M] were found in the post-rolandic area contralateral to the stimulation. The wave form in SEPs(M) was similar to those in SEPs(E), but the peak latency of each component in SEPs(M) was 1-4 msec longer than that in SEPs(E). Earlier components such as P19(M), N24(M) and P29(M) were not as clearly recognized as corresponding components in SEPs(E). However, the wave form recorded on the hemisphere ipsilateral to the stimulation or in the frontal area contralateral to the stimulation showed a greater difference from subject to subject. P19(M), N24(M) and P29(M) correlated positively both with arm length and height of the subject. There was no significant difference of the wave form between the linked ear reference and the bipolar (C4-Fz) derivation. Wave form of SEPs(M) by needle stimulation did not significantly differ from that by plastic ball stimulation.

Adult↗
PubMed1984

Minimal record of disability in multiple sclerosis--application to Japanese patients.

The Japanese version of Minimal Record of Disability in MS was applied to randomly selected Japanese MS cases in order to determine the applicability of the scales and also to get the general trends of the disabilities of Japanese MS. The scales did reflect impairment of functional systems, in which visual system was most severe. The average DSS was 4/10. Incapacity status or environment status were well correlated with impairment of pyramidal or bowel/bladder systems. They also correlated with DSS. Duration of the illness was correlated with the severity of impairment, disability or handicap. Accumulation of such a core data base may help in management of the MS problems in the world.

Activities of Daily Living↗