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Biomedical subjects

S Tobimatsu

Publications and source records attributed to S Tobimatsu.

At least 91 records · Page 5Linked 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

Multimodality evoked potentials in patients and carriers with adrenoleukodystrophy and adrenomyeloneuropathy.

A combination of brain-stem auditory evoked potentials (BAEPs), short latency somatosensory evoked potentials (SEPs) and pattern reversal visual evoked potentials (VEPs), were studied in two patients with adrenoleukodystrophy (ALD) and one patient with adrenomyeloneuropathy (AMN), as well as in one female carrier of each of the respective diseases. Abnormalities in at least 1 of the 3 evoked potentials were found in every case, including the carriers of ALD and AMN. The two most common findings were prolongation of the I-V interval of the BAEP and the N13-N20 interval of the SEP. These abnormalities were recorded either alone or in combination in all 5 cases. This finding suggests delayed conduction time in the central sensory pathways in both diseases, probably due to demyelination. The remarkable result, which distinguished AMN from ALD, even in their respective carriers, was delay of the N9 latency of the SEP, indicating slowing in conduction velocity of the peripheral nerve. Multimodality evoked potentials are useful not only in raising the detection rate for abnormal findings, but also in providing additional information about the functional state of separate afferent pathways. It is also of value in detecting and differentiating the carriers of ALD and AMN.

Adrenal Gland Diseases↗
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↗
PubMed1984

Local cerebral glucose utilization altered in rats with unilateral electrolytic striatal lesions and modification by apomorphine.

Alterations in local cerebral glucose utilization (LCGU) in rats with unilateral striatal lesions and the modification by apomorphine were investigated. Electrolytic lesions were made in the rostral part of the right striatum, and 1, 7, and 30 days later, LCGU was observed in terms of relative and absolute LCGU values, using the [14C]deoxyglucose method. A definite change in the pattern of LCGU was seen only at 7 days. These were increases in LCGU in the globus pallidus, entopeduncular nucleus and substantia nigra pars reticulata, and decreases in the ventroanterior-ventrolateral (VAL) and ventromedial (VM) thalamic nuclei and lateral habenula, all on the lesioned side. The circling behavior following the lesion, however, was maximal after 2 days and disappeared after 7 days. Intravenous administration of apomorphine (1.5 mg/kg) produced different modifications in the LCGU pattern between the intact and lesioned sides, at 7 days after producing the lesions. On the intact side, there were increases in LCGU in the striatum, globus pallidus, entopeduncular nucleus, substantia nigra pars reticulata and subthalamic nucleus, and a decrease in the lateral habenula. No such changes were observed on the lesioned side. These results indicate firstly that electrolytic striatal lesions induce LCGU increases or decreases in the structures which receive the striatal input, secondly that the mechanism of this change differs from that of the circling behavior seen in case of striatal lesions, and finally that the majority of the LCGU changes in the basal ganglia and thalamus following intravenous administration of apomorphine are brought about by an altered input of neuronal activity from the striatum to these structures.

Animals↗
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↗
PubMed1982

Increased local cerebral glucose utilization in the basal ganglia of the rolling mouse Nagoya.

Rolling mouse Nagoya (rolling), an experimental mutant mouse, is characterized by a marked incoordination of the hind limbs and disturbance of gait. These motor disturbances have been attributed to cerebellar dysfunction, and rolling, therefore, has been regarded as an animal model of hereditary cerebellar ataxia. However, definite evidence for this possibility has not yet been provided. In the present study, local cerebral glucose utilization (LCGU) was observed by means of the [14C]deoxyglucose method in rolling (rol/rol), as well as in behaviorally normal heterozygotes (+/rol) and normal controls (+/+), in order to study functional activity of the brain in these mice. A definite increase in LCGU was found in the globus pallidus, entopeduncular nucleus, subthalamic nucleus, and substantia nigra of rolling, bilaterally. A minimal decrease in LCGU was also found in the vermis of the cerebellum. These findings reflect the markedly hyperactive state of the basal ganglia and the minimally hypoactive state in the vermis of the cerebellum in rolling. It is concluded that the dysfunction in the basal ganglia is the major cause of the motor disturbances of rolling, and that rolling may be regarded as an animal model of extrapyramidal motor disturbance.

Animals↗
PubMed1982

Dentatorubropallidoluysian degeneration: clinical, neuro-ophthalmologic, biochemical, and pathologic studies on autosomal dominant form.

Four cases in two generations of a Japanese family are described as affected by an autosomal dominant-inherited cerebellar ataxia, pyramidal and extrapyramidal signs, and abnormal ocular movements, resembling Machado-Joseph disease. The neuro-ophthalmologic examination suggests the involvement of multiple motor control systems. The neuropathologic examination of one case showed neuronal loss in the subthalamic nuclei, pallidum, dentate nuclei of cerebellum, and red nuclei, which is distinct from Machado-Joseph disease.

Adult↗
PubMedDate not supplied

Effect of check size on the pattern reversal visual evoked potential.

Modifications of the components of pattern-reversal visual evoked potentials (PR-VEP) with changes in check size of the stimulating pattern were studied in 11 healthy subjects. We made use of 8 different check sizes ranging between 10 and 90 min of arc. Changes in the check size modified in different manners the latencies and amplitudes of N75, P100 and N145. Two-step statistical analyses using the polynomial regression analysis method revealed significant modifications of latencies of the 3 components, but non-significant modifications of the amplitudes, except for N75. The latency and amplitude of N75 showed a significant inverse linear relationship with the logarithm of the check size, while the P100 and N145 latencies showed significant curvilinear relationships, with minimal latencies at check sizes around 35 min. These findings suggest different physiological properties of N75 from those of P100 and N145, and hence, the necessity to establish normal values for each check size of stimulation, for application in clinical studies.

Adult↗
PubMedDate not supplied

Origin and distribution of brain-stem somatosensory evoked potentials in humans.

The distribution of somatosensory evoked potentials (SEPs) recorded from the brain-stem surface was studied to investigate their generator sources in 14 patients during surgical exploration of the posterior fossa. Two distinct SEPs of different morphologies and electrical orientation were obtained by median nerve stimulation. A small positive-large negative-late prolonged positive wave was recorded from the cuneate nucleus and its vicinity. There was a phase-reversal between the cuneate nucleus and the ventral surface of the medulla, depicting a dipole for dorso-ventral organization. From the pons and midbrain, triphasic waves with predominant negativity were obtained. This type of SEP had identical wave forms between the dorsal, lateral and ventral surface of the pons and midbrain. It showed an increase in negative peak latency as the recording sites moved rostrally, suggesting an ascending axial orientation. In a patient with pontine hemorrhage, the killed end potential, a large monophasic positive potential was obtained from the lesion. This potential occurs when an impulse approaches but never passes beyond the recording electrode. Therefore, the triphasic SEP from the pons and midbrain reflects an axonal potential generated in the medial lemniscal pathway.

Adolescent↗
PubMedDate not supplied

Clinical relevance of phase of steady-state VEPs to P100 latency of transient VEPs.

Pattern visual evoked potentials (VEPs) to transient and steady-state stimulation were recorded in 10 normal subjects at 4 levels of luminance (180, 57, 22 and 11 cd/m2). VEPs were also recorded in 5 patients with optic neuropathy at a fixed luminance (180 cd/m2). The relationship between P100 latency of transient VEPs (T-VEPs) and the phase of steady-state VEPs (S-VEPs) was analyzed. As luminance decreased in normal subjects, P100 latency was prolonged and the phase lag increased. A significant linear relationship between the P100 latency and phase was found. Patients showed both the prolonged P100 latency and the delayed phase. The simple linear regression line of the phase-P100 latency function of normal subjects closely matched the patients' values. These results suggest that changes in the phase may be equivalent to changes in the P100 latency. S-VEPs, therefore, may be clinically useful in assessing visual function.

Adult↗