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Biomedical subjects

S Toya

Publications and source records attributed to S Toya.

187 records · Page 11Linked to original sources
PubMedDate not supplied

Distribution of PASII/PMP22 and connexin 32 proteins in the peripheral nervous system.

Various mutations of PO, PASII/PMP22 and connexin 32 genes were recently reported in hereditary neuropathies, such as Charcot-Marie-Tooth disease (CMT) and Dejerine Sottas disease (DS). However, physiological roles of the proteins in PNS are not well understood. To address the functions of the proteins, we examined their localization in PNS comparatively by immunohistochemical methods. In Western blotting, a polyclonal antibody against the carboxyl terminal peptide of PASII/PMP22 reacted to 20-24 kD bands of PASII/PMP22 in mammalian PNS myelin, but produced no reaction in either mammalian or carp CNS myelin proteins. Monoclonal anti-connexin 32 antibody recognised connexin 32 of a dimer or monomer form in rat and human PNS myelin. By histological examination, PASII/PMP22 expressed dominantly in rat PNS compact myelins, while connexin 32 localized exclusively in the nodes of Ranvier, but not in compact myelins. In cell culture, axonal contact induced a remarkable increase of PASII/PMP22 in the Schwann cell in contrast to faint staining in immature Schwann cells. While localization of connexin 32 is quite different from that of PASII/PMP22, the mutations of the two proteins often induce similar phenotypes of hereditary neuropathies.

Animals↗
PubMedDate not supplied

Experimental study on changes of the spinal-evoked potential and circulatory dynamics following spinal cord compression and decompression.

In an attempt to elucidate the pathogenesis of spinal cord injury, the authors investigated the changes in spinal-evoked potential (SEP) and serial fluorescein angiography during compression and after decompression of the thoracolumbar cord in dogs. The degree of compression was correlated well with the changes in SEP during compression and after decompression. The findings of serial fluorescein angiography immediately after decompression indicated hyperemia and extravasation of the fluorescein dye, especially in the group weighted with 36 and 60 g. Poor filling of the arteries and veins with fluorescein dye, and prolongation of the regional circulation time were observed at between 30 and 120 minutes after decompression in the group weighted with 36 and 60 g. These findings suggest that secondary circulatory disturbance plays an important role in the pathogenesis of spinal cord injury. The relation between changes of SEP and the circulation are also discussed.

Animals↗
PubMedDate not supplied

Implantation of xenogeneic transgenic neural plate tissues into parkinsonian rat brain.

Xenografting must be considered as a means of establishing neural transplantation therapy and of securing fetal neural tissues as donor material. The early stage (embryonic day 8.5, E8.5) embryonic mesencephalic neural plate (NP) from transgenic mice was examined for possible application in effective xenografting therapy. As recipients, Parkinsonian rats treated with 6-hydroxydopamine were used, and as donors, GT4-2 mice into which a beta-galactosidase gene was introduced to allow brain tissue differentiation from the recipients by X-gal staining. Three microscopic pieces of E8.5 GT4-2 mice NP were injected into the striatum of the Parkinsonian rats. Some hosts were given immunosuppressants (cyclophosphamide and FK506) (IS group), others were not (non-IS group). Amphetamine-induced rotation was examined at days 11 and 21 after grafting (D11 and D21, respectively), and morphological investigations were performed using hematoxylin-eosin (H-E), X-gal, and thyrosine hydroxylase (TH) staining. The rotations were counted in 30 of the 38 transplanted rats before and after grafting. Histological data were obtained from 19 of these 30 rats. In 11 of them the grafts survived (survival group) and in the remaining 8, the grafts were unsuccessful (rejection group). In the survival group at D11, the mean number of rotations made by transplanted rats expressed as a percentage of the number before grafting (rotation percentage) decreased to 43.8% (n = 9), which, in comparison with the average of 125.9% (n = 6) in the rejection group, reveals significant behavioral recovery (p < 0.01). The rotation percentage at D21 was 23.8% in the survival group (n = 4) and 84.5% in the rejection group (n = 3). Behavioral recovery was thus seen to improve with time in the survival group. In the IS group (n = 19), the rotation percentages averaged 74.9% (D11, n = 15) and 51.1% (D21, n = 7), while the non-IS group averages were 136.7% (D11, n = 9) and 140.7% (D21, n = 9), indicating a tendency for better behavioral recovery in the IS group than in the non-IS group (p < 0.05). Fifteen IS group rats were studied histologically, 10 (sacrificed on D11, D21) from the survival group and 5 (sacrificed on D11, D21) from the rejection group, In the non-IS group (n = 4), there was a graft in only one rat sacrificed on D11. There were many X-gal positive and TH positive cells in the grafts, suggesting that mouse NP survived, and differentiated into TH positive neurons in the rat brain. Xenografted NP has the potential to cure central nervous system diseases.

Amphetamine↗
PubMedDate not supplied

Hearing preservation in acoustic neuroma surgery and postoperative audiological findings.

One hundred fifty-three cases of acoustic neuroma were treated surgically by the middle cranial fossa approach or extended middle cranial fossa approach. Attempts to preserve hearing were made in 30 cases with tumours extending 2.0 cm or less into the posterior fossa; successful hearing preservation was achieved in 12 cases. Among the 15 patients with preoperative hearing levels (HL) of 50 dB or lower and speech discrimination scores (SDS) of 50% or higher, hearing was preserved in 9 (60%) patients. A similar rate of hearing preservation was achieved among the patients with normal or near-normal hearing. Compared with those patients in whom hearing could not be preserved, those with hearing preservation had better HL, higher SDS, and less abnormal ABR findings preoperatively. Postoperatively, the HL and SDS deteriorated slightly. In addition, there was a marked prolongation of the IT5, and the incidence of absence of the stapedius reflex increased. Compared with the preoperative HL, the postoperative HL was unchanged in 5 cases; deteriorated temporarily and then improved in 5 cases; and deteriorated, though with hearing preserved, in 2 cases. Intraoperative monitoring was conducted by recording the ABR and VIII nerve compound action potentials and by electrocochleography. However, postoperative hearing could not always be predicted from the findings obtained at the end of the operation.

Audiometry↗