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M Matsunaga

Publications and source records attributed to M Matsunaga.

At least 55 records · Page 3Linked to original sources
PubMed1999

[A case of clinically diagnosed corticobasal degeneration with unilateral cortical reflex myoclonus showing so-called giant SEP].

We report a 66-year-old woman clinically diagnosed as having a corticobasal degeneration (CBD), who showed electrophysiologically cortical reflex myoclonus. She developed a clumsiness and action myoclonus on the right extremities, and aphasia. The extrapyramidal signs such as dystonia and rigidity were also noted on the right side. Sequential MR images showed a progressive brain atrophy in the left frontoparietal area, where a blood perfusion was reduced on single photon emission computed tomography (SPECT). The median nerve stimulation on the affected right side, but not left side, elicited an enhanced long-loop reflex. The onset latency of the long-loop reflex (43.8msec) was similar to that of the reported cases of CBD (Thompson et al, 1994); but, significantly shorter than that reported in the patients with typical cortical reflex myoclonus. The right median nerve stimulation also elicited so-called giant somatosensory evoked potentials (SEPs). On the basis of the scalp topography of the giant SEPs, we found the high amplitude central P22-N30 components to reflect a radial dipole. We also recorded the myoclonus-related cortical spike by jerk-locked back averaging. Both the giant SEP and myoclonus-related cortical spike were recorded only on the left scalp. We therefore suggest that these two cortical activities are similar in terms of wave form, scalp topography and time relationship to either the long-loop reflex or myoclonus and may be located in the precentral area. This is the first report of a patient with CBD presenting both the giant SEP and myoclonus-related cortical spike.

Aged↗
PubMed1998

High frequency oscillations in early cortical somatosensory evoked potentials.

OBJECTIVE: To evaluate the characteristics of high frequency (HF) components of the early cortical somatosensory evoked potentials (SEPs). METHODS: We recorded 8-channel SEPs from the frontal and left centro-parietal scalp after right median nerve stimulation with a wide band-pass (0.5-2000 Hz) and digitized at 40 kHz sampling rate in 12 healthy subjects. HF components were analyzed after digital band-pass filtering (300-1000 Hz). The power spectrum was obtained by a maximum entropy method. RESULTS: HF oscillations (maximum power at 600-800 Hz) consisting of 5 to 8 peaks were discriminated from the preceding P14 far-field in all cases and their phases were reversed between the frontal and contralateral parietal regions. In addition, in subjects with a high amplitude central P22 potential in original wide-band recordings, a single HF oscillation with a maximum at the central region was present. Furthermore, this component showed no phase reversal over the centro-parietal area. CONCLUSION: We therefore conclude that HF oscillations are superimposed not only on the tangential N20-P20 but on the radial P22 potential, and are generated from both tangential (area 3b) and radial (area 1) current sources.

Adult↗
PubMed1998

Immunoadsorption plasmapheresis in acute ataxic neuropathy.

Acute ataxic neuropathy is characterized by sensory ataxia and areflexia. There is no established treatment. We tried immunoadsorption plasmapheresis 15 days after the onset for a 46-year-old woman suffering from this neuropathy. She could not walk even with assistance because of sensory ataxia. A sural nerve biopsy revealed active axonal degeneration and loss of myelinated fibers. We tried 5 sessions of plasmapheresis during 2 weeks. She could walk with assistance 12 days after the beginning of the plasmapheresis treatment. It took 3 months for her to be able to walk over 5 m without assistance, and she had severe sensory ataxia over a 17 month follow-up period. Immunoadsorption plasmapheresis started within 2 weeks after the onset of acute ataxic neuropathy may have beneficial effects if the axonal degeneration is mild. The plasmapheresis, however, should be continued for a longer period. A double blind study is necessary to clarify the effectiveness of this treatment on acute ataxic neuropathy.

Acute Disease↗
PubMed1998

[Reduction of apomorphine-induced rotation in rats with additional destruction of the pedunculopontine nucleus contralateral to the unilateral nigrostriatal lesion].

Pedunculopontine nucleus (PPN) has been proposed to be one of the responsible sites for dopamine agonist induced contraversive rotation in rats with unilateral dopaminergic denervation. However, previous experiments have not confirmed possible participation of PPN in this rotational behavior. To determine whether contralateral side of the PPN plays a vital role in this rotation, we investigated apomorphine induced rotation in rats with further destruction of unilateral PPN contralateral to the nigrostriatal lesion. First, rats with unilateral PPN lesioned with N-methyl-D aspartic acid (NMDA) showed contralateral rotation when they were injected with apomorphine 0.5 mg/kg s.c. Second, rats with right substantia nigra previously lesioned with 6-hydroxydopamine were microinjected with NMDA (PPN lesion group) or vehicle (sham lesion group) into the contralateral (left)side of the PPN. Contraversive rotation induced by apomorphine 0.05 mg/kg s.c. did not show any significant change in PPN lesion group as compared with sham lesion group. Whereas such rotation induced by apomorphine 0.5 mg/kg s.c. significantly reduced to 61% in PPN lesion group as compared with that in sham lesion group. These results could be interpreted as a partial cancellation of rotational activity to the contralateral side (left) by the potential rotational activity toward the opposite side (right) in rats with additional contralateral PPN lesion. Although PPN might not serve as an output route for the dopaminergic neurotransmission in the basal ganglia, PPN itself could rather induce some movement affecting the basal ganglia.

Animals↗
PubMed1997

Cervical cord ependymoma with numerous microrosettes.

"Microrosette ependymoma," which is ependymoma with numerous microrosettes throughout the tumor, has rarely been reported. We describe an autopsy case of cervical cord ependymoma with two unusual features: the presence of numerous microrosettes and the formation of trabecular architecture. The tumor originated in the C2 segment of a man aged 23 years and gradually expanded over the following 15 years and 10 months until the entire cervical cord was involved. Beside the low grade of malignancy, the tumor cells exhibited a strong tendency to form microrosettes and trabecular architecture, which formed many perivascular pseudorosettes. The microrosettes mostly consisted of only two or a few more cells, in the absence of large rosettes. Thus the constituent cells were those forming perivascular pseudorosettes. Electron microscopy and immunohistochemistry characterized the ependymal properties of the microrosettes, whose lumina frequently contained fibril bundles similar to those of the Reissner's fiber fibrils, in addition to cilia and microvilli. The pathogenesis of the occurrence of numerous microrosettes is unknown; however, a defect in the mechanism of regulation of rosette formation and enlargement is the most likely explanation.

Adult↗
PubMed1997

Effect of weight loss on body fat distribution in obese children.

The intra-abdominal visceral fat to subcutaneous fat ratio (V/S ratio) has been reported to be strongly related to disorders of glucose and lipid metabolism, and hypertension. It is a matter of concern as to whether weight loss causes an improvement of the V/S ratio or not in obese children. Changes in body fat distribution during weight loss in 23 obese children were quantified by weight, bioelectrical impedance analysis (BIA) and computed tomography (CT scan of the abdomen). Twenty-three patients were divided into two groups; six were in the inpatient group and 17 were in the outpatient group. Bodyweight, body fat percentage, subcutaneous fat and visceral fat were significantly higher in the inpatient group than in the outpatient group before weight loss. Whereas the V/S ratio was almost equal between the two groups before weight loss. Bodyweight, body fat percentage, subcutaneous fat and visceral fat were found to decrease significantly during weight loss in the two groups. The V/S ratio of the outpatient group did not change after weight loss. In contrast, the V/S ratio of the inpatient group decreased significantly during weight loss. These preliminary findings suggest that a large amount of body fat and a high obesity rate are not always accompanied by a high V/S ratio in obese children. The fat pattern changes during weight loss with strict dietary therapy and therapeutic exercise. A larger sample of obese children should be studied to test this conjecture.

Abdomen↗
PubMed1997

Long-lasting muscle relaxant activity of eperisone hydrochloride after percutaneous administration in rats.

Potency and duration of muscle relaxant activity of eperisone hydrochloride were examined after percutaneous administration in the intercollicular decerebrated rat rigidity model and compared to those of eperisone after intravenous injection. A continuous movement was loaded on the hindlimb of the rat model to maintain stable rigidity. The tonus of the hindlimb was recorded by EMG from the triceps surae and was quantified by using the public domain NIH Image program. Eperisone ointment administered percutaneously showed significant muscle relaxant activity at 8.4 cm2 (4.2 mg of eperisone)/rat. The effect was dose-dependent and lasted over 60 min. Intravenously injected eperisone showed significant activity at 1.25 mg/kg, but the decrease of tone was lost within 30 min after injection. Plasma eperisone levels were monitored in the same model, and they were well correlated to the dosage. These results suggest that percutaneously administered eperisone is absorbed efficiently and shows potent and long-lasting muscle relaxant activity.

Administration, Cutaneous↗
PubMed1997

Strychnine-sensitive and strychnine-insensitive glycine binding sites in the spinal cord of the wobbler mouse.

Using quantitative autoradiography, the strychnine-sensitive glycine site and strychnine-insensitive glycine site of the N-methyl-D-aspartate receptor were analyzed in the cervical segment of the spinal cord of the wobbler mouse, which is a purported model of human motor neuron diseases. Significantly increased density of the strychnine-sensitive site was found in the lamina II-inner (+17%) and laminae III & IV (+17%) of wobbler mice. The strychnine-insensitive site was also increased in lamina I & II-outer (+15%), lamina II-inner (+15%), laminae III & IV (+48%), laminae V-VIII (+43%) and lamina X (+26%) of wobbler mice. However, no significant differences were observed for the both sites in the ventral horn where motor neurons are located. These findings suggest that both inhibitory and excitatory-associated glycinergic dysfunctions are involved in the wobbler mouse motor neuron disease.

Animals↗
PubMed1997

Changes in motor nerve terminals following proximal constriction by a ligature.

To elucidate the effect of proximal constriction on motor nerve terminals, silk ligations were placed around the tibial nerve in the thigh of rabbits. The ligatures were tight enough to cause Wallerian degeneration in most of the large myelinated fibers; we studied those which remained unaffected. A week after operation, 9 animals showed a fall in amplitude of medial plantar muscle action potential to less than 30% of the pre-operative value on tibial nerve stimulation at the ankle. They were killed after keeping the constriction from 10 to 100 days, and the medial plantar muscles were removed for histological studies on the motor terminals of the medial plantar nerve. AChE-silver staining showed many nerve endings without terminal axons, and "junctional" terminals showing preservation of the continuity proximal to complete degeneration from 10 days to the 40 days after ligation. A few terminal and nodal sproutings were found 10 days after ligation. Transverse sections of the intramuscular portion of the medial plantar nerve showed a decrease in number of the large myelinated fibers. While the ratio of axonal caliber/external diameter of large myelinated fibers (g-ratio) was reduced, g-ratio of small myelinated fibers were varied but as high as that in normal controls from 40 days after ligation. These results indicate distal axonal degeneration (dying back) of the terminal fibers besides the Wallerian degeneration at the level of the ligature and inhibited distal sproutings, which are probably caused by a local disturbance of axonal transport resulting from proximal constriction.

Action Potentials↗
PubMed1997

[On intra-familial clinical diversities of a familial amyotrophic lateral sclerosis with a point mutation of Cu/Zn superoxide dismutase (Asn 86-Ser].

In a familial amyotrophic lateral sclerosis (FALS) with SOD-1 mutation (Asn 86-Ser), there were intra-familial clinical diversities. The proband, a daughter patient, shows a mild clinical course of 16 years. Her father died of respiratory failure in 3 years. His initial symptom was weakness of upper extremity. The daughter's first symptom was that of lower extremities. Her respiratory-assist started after 9 years from the onset. She is alive under whole-day respiratory assist while she had been taking nutrients per os for 15 years. Her abilities of swallowing remain, even more dependent of tube-feeding (15 years after the onset). The fact of the presence of intra-familial clinical varieties with SOD-1 mutation in FALS suggests that the mutation is not an exclusive factor to determine the clinical phenotype, age of the onset and rapidity of illness of FALS associated with SOD-1 mutation. We collect reports of FALS with SOD-1 mutation which have similar diversities of intra-familial clinical manifestations as our family. Varieties of intra-familial clinical manifestations of motor neuron disease are shown in 9 families with SOD-1 mutation. The genetic error appears to have a limit, and is not a exclusive cause of FALS. However, we should not underestimate the significance of the discovery of a gene, since it might offer a clue to still unanswered riddle of ALS pathogenesis.

Amyotrophic Lateral Sclerosis↗
PubMed1996

The relation between respiratory inhibition and uptake of 1-methyl-isoquinoline (MIQ+) in mitochondria.

The effect of 1-methyl-isoquinoline (MIQ+) on the respiratory inhibition and the uptake of MIQ+ were measured using mouse liver mitochondria. MIQ+ inhibited the electron transport of complex I but did not inhibit the respiration of mitochondria with succinate as a substrate. MIQ+ was taken up by mitochondria in an energy dependent process. Tetraphenylboron enhanced the MIQ+ uptake by mitochondria and its inhibitory effect on respiration. The respiratory inhibition of mitochondria by MIQ+ resulted in release of MIQ+ from mitochondria in medium containing glutamate and malate. These characteristics of MIQ+, for uptake into mitochondria and respiratory inhibition, were similar to those of 1-methyl-4-phenylpyridine (MPP+). The IC50 of MIQ+ for respiratory inhibition was higher than that of MPP+, and the amount of MIQ+ uptake by mitochondria was smaller that of MPP+. The lower ability of MIQ+ for respiratory inhibition as compared to that of MPP+ must result from the lower lipophilic ability of MIQ+ than that of MPP+. These results show that, unlike MPP+, MIQ+ cannot act as a rapid neurotoxin. But, it does not eliminate the possibility that MIQ+ acts as a neurotoxin in the long-term, since MIQ+ was taken up in mitochondria and inhibited the respiration.

1-Methyl-4-phenylpyridinium↗
PubMed1996

N30 in PD.

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Brain↗
PubMed1996

Central conduction in somatosensory evoked potentials: comparison of ulnar and median data and evaluation of onset versus peak methods.

To compare central conduction in ulnar and median nerve somatosensory evoked potentials (SEPs), we recorded SEPs from the neck and scalp elicited by median and ulnar nerve stimulation in 46 normal young adults. We determined the central conduction time (CCT) in each subject from peak-to-peak and onset-to-onset measurements. The mean value of the onset CCT for the ulnar nerve SEP was 6.2 +/- 0.3 msec, and for the median nerve SEP, 5.9 +/- 0.3 msec. Onset CCT was significantly longer for the ulnar nerve SEP, and there was a significant correlation between onset CCT in both median and ulnar nerve SEPs and subject height. In contrast, the mean value of the "conventional" peak CCT for the ulnar nerve SEP was 5.6 +/- 0.6 msec, and for the median nerve SEP, 5.8 +/- 0.5 msec, with no significant difference between them. In addition, the peak CCT was not correlated with subject height in the ulnar or median nerve SEPs. Our findings suggest that onset CCT measurement is superior to the conventional peak CCT measurement for ulnar as well as median nerve SEPs, and confirm that the central conduction pathway for the ulnar nerve SEP is slightly longer than that for the median nerve SEP.

Adolescent↗
PubMed1996

Uptake of 1-methyl-4-phenylpyridinium ion (MPP+) and ATP content in synaptosomes.

Symptoms such as those in Parkinson's disease are known to be induced by the neurotoxin, 1-methyl-4-phenylpyridinium (MPP+). We tried to quantitatively measure synaptosomal MPP+ uptake using an MPP+ selective electrode to study the correlation between MPP+ uptake and respiratory inhibition. Synaptosomal MPP+ uptake was low but could be increased by the addition of glucose as an energy substrate, or increased with an increase in the concentration of MPP+. The rate of uptake was 0.2 nmol/mg protein/min at 50 microM MPP+. Tetraphenylboron (TPB+), which enhances cation permeability, increased MPP+ uptake, and the increase was proportional to the TPB+ concentration. When external MPP+ concentration was increased above 200 microM, ATP was depleted and the uptake of MPP+ decreased, which resulted in the release of intrasynaptosomal MPP+. MPP+ uptake was also decreased by depolarization of the membrane potential in synaptosomes. MPP+ was presumed to be distributed across both the synaptosomal and inner mitochondrial membranes, and to be affected by membrane potential as a lipophilic cation. When respiration of the inner mitochondria was inhibited by increasing the intrasynaptosomal MPP+ concentration, the concentration of MPP+ in cytosol was presumed to increase by the release of MPP+ from the mitochondria, and synaptosomal MPP+ uptake would then be decreased.

1-Methyl-4-phenylpyridinium↗
PubMed1996

[Isaacs' syndrome with abnormal F response and effects of double filtration plasmapheresis: a case report].

We reported a case of Isaacs' syndrome with abnormal F response detected electrophysiologically. A 14-year-old female was admitted to Hirosaki University Hospital with complaints of progressive myokymia and muscle cramp. PHT and CBZ were partially effective, but discontinued for drowsiness. A neurological examination revealed prominent myokymia and muscle cramp in the legs. The myokymia were worsened by exercise, bathing and diet. An electrophysiological examination showed characteristic F-response; high amplitude, long duration and increased number of phases. The epidural nerve block brought about a disappearance of the myokymia and an improvement of the abnormal features of F response. After repeated double filtration plasmapheresis, the myokymia and abnormal features of F response were remarkably reduced. Although Isaacs' syndrome is thought to have a hyperexcitability at the site of distal peripheral nerve, we suggested that the hyperexcitability might exist at the site of proximal region, and that immunological mechanisms underlie the cause of myokymia and unusual F-response in this case.

Adolescent↗
PubMed1996

[Treatment of chronic inflammatory demyelinating polyneuropathy (CIDP)].

Fifty patients with CIDP were treated with cortico-steroids (CS), plasmapheresis (PP) and human immunoglobulin (IG). Objective improvements in strength and in nerve conduction occurred in 53% of the patients after CS. In 50% of the non-responders to CS showed objective improvements after PP, and 40% of them responded to IG. Complete remission was achieved in only one patient. Around 15% of the patients showed poor response to any treatments. Azathioprine combined with CS induced little objective improvements.

Adolescent↗
PubMed1995

"Pseudo" hypertrophic neuropathy of childhood.

A 9 year old boy had chronic progressive motor-sensory neuropathy that started in early infancy. He had enlarged nerves and pes cavus deformity. Motor conduction studies showed very dispersed, polyphasic compound muscle action potentials with conduction velocities around 2 m/s. A sural nerve biopsy showed severe loss of myelinated fibres. Two months of treatment with corticosteroids restored muscle power. During this time the enlarged nerves became normal and electrophysiological recovery was achieved. Chronically acquired neuropathy in infancy is strikingly similar to genetically determined neuropathy.

Child↗