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Biomedical subjects

S Toya

Publications and source records attributed to S Toya.

At least 91 records · Page 5Linked to original sources
PubMed1992

[Radiosensitive malignant meningioma presenting Garcin's syndrome: a case report].

A 58-year-old woman with Garcin's syndrome caused by malignant meningioma is reported. She first noticed left facial hypesthesia followed by left visual disturbance with exophthalmos. CT scan showed an enhanced mass extending from the left cavernous sinus to the left orbit. Cranial x-ray revealed bone deformity around the orbit. The tumor was subtotally resected and its histological type was shown to be anaplastic meningioma. After the initial surgery the patient was left with hyposmia, mild ptosis and incomplete 6th cranial nerve palsy on the left side. After one and half years, not only palsy of those cranial nerves but also that of other unilateral cranial nerves became progressively apparent due to tumor regrowth. In total, 11 nerves (2nd-12th) were affected by the tumor, without long tract signs or symptoms of increased intracranial pressure. Radiation therapy carried out after the 2nd surgery was extremely effective and resulted in the recovery of lower cranial nerve function. The tumor was founded to have disappeared completely on the 2-year follow-up CT.

Combined Modality Therapy↗
PubMed1991

Classification of the extended middle cranial fossa approach.

There are several possible operative approaches to acoustic neuroma surgery. Ideally, there should be no need to select among approaches according to tumor size or indications for hearing preservation. The ideal approach should also allow otologists and neurosurgeons to work as a team using the same operative field and achieve functional preservation (facial nerve function and hearing) in a high percentage of cases. In 1977, the authors first reported on the extended middle cranial fossa (EMCF) approach for AN surgery. Based on our 15-year experiences of this approach, we have classified it into 3 types and describe their indications and techniques in the present paper. In addition, we examine the advantages and disadvantages and emphasize its excellent applicability as a team approach for otologists and neurosurgeons.

Cerebellum↗
PubMed1991

Results of acoustic neuroma surgery by the extended middle cranial fossa approach.

The results of surgery in 160 cases of AN are reported. Surgery was carried out by the extended middle cranial fossa (EMCF) approach in 138 cases and by the middle cranial fossa (MCF) approach in 22 cases. The tumor extended an average of 28.9 mm into the posterior cranial fossa; 42% of the tumors extended 31 mm or more. Mortality was 1.9%. Of the 3 cases of death, two had large tumors of 45 mm and 52 mm each, and one was a case of recurrence. Total tumor removal was achieved in an average of 78.8% of the cases. When the cases were classified by date of operation, the total tumor removal rate in the 60 most recent cases was 93.3%. The rate of facial nerve presentation was 82.4% on average and 93% in the recent cases. Hypoglossal-facial nerve anastomosis was performed in 33% of the cases in which facial nerve function failed to recover for an extended period of time. Among recent cases, however, anastomosis has been carried out in 22% of the cases. Hearing was preserved in 20 cases. Useful hearing was preserved in 8 (38%) of 22 cases. Recurrence was confirmed through surgery in 3 cases. Recurrence was suspected but was unconfirmed in 3 cases.

Adolescent↗
PubMed1991

Hearing preservation in acoustic neuroma surgery by the extended middle cranial fossa method.

The results of attempted hearing preservation were investigated in 160 cases of acoustic neuroma surgery carried out by a team of otologists and neurosurgeons at Keio University Hospital during a 14-year period from 1976 to 1989. Surgery was carried out by the middle cranial fossa (MCF) approach in the earlier cases and by the extended middle cranial fossa (EMCF) approach in the more recent cases. Measurable postoperative hearing was preserved in 20 of the 160 cases. Preoperatively, 22 cases had tumors of 20 mm or smaller in diameter, hearing levels (HL) of 50 dB or lower, and speech discrimination scores (SDS) of 50% or higher; 8 (36%) met these conditions postoperatively. Among those cases with hearing preserved postoperatively, hearing was unchanged from the preoperative level in 9 cases and changed in 11 cases. Total tumor removal was achieved in 19 cases. In one case, part of the tumor was left in order to preserve hearing, but MRI and CT have revealed no change in hearing or tumor enlargement to date, at 4 1/2 years after surgery. Hearing was preserved but progressively deteriorated postoperatively in one case in which the tumor was believed to have been totally removed but there was recurrence and in another case of total resection of neurofibromatosis II. Postoperatively, there were increased incidences of absence of the stapedius reflex, Type V by Békésy audiometry, and prolongation of the IT5, disappearance of Wave V, and no response in measurements of the ABR.

Adolescent↗
PubMed1991

Preservation of facial nerve function in acoustic neuroma surgery by the extended middle cranial fossa approach.

The anatomical preservation rates of the facial nerve and postoperative facial nerve function were investigated in cases of initial operation for acoustic neuroma by the middle cranial fossa or extended middle cranial fossa approach. The cases were divided chronologically into three groups according to the date of surgery. The rate of anatomical preservation was 93% in the most recent period, compared to 82.4% for the entire series. This was attributable to higher preservation rates being achieved in cases with medium or large tumors with increased experience. Also regarding postoperative facial nerve function, the number of cases with no paralysis or only partial paralysis increased and the number of cases requiring sacrifice of the facial nerve decreased as experience was accumulated in the series. Even when the facial nerve was preserved anatomically, however, facial-hypoglossal anastomosis was carried out actively if facial nerve function did not recover satisfactorily one year after surgery. For this reason, as many as 33% of the patients underwent anastomosis. This high percentage, however, is attributable to anastomosis ultimately being carried out in 47.7% of the patients in the early period; 22.2% of the patients in the most recent period underwent anastomosis.

Adolescent↗
PubMed1991

Effects of astroglia on the development of cultured neurons from embryonic rat cerebral cortex.

1. Previous studies from our laboratory demonstrated that subcultured astroglia enhance neurite outgrowth and survival of cultured neurons from embryonic rat cerebral cortex, but suppress proliferation of neuroblasts. 2. In the present study, the mechanisms of these three effects were further investigated. 3. Dissociated neurons were seeded on poly-L-lysine-coated coverslips which were plated on subcultured astroglia, and the survival, proliferation and neurite outgrowth of the neurons were investigated. Under these conditions, survival and antimitotic effects were also observed, while neurite extension was not stimulated. 4. The results clearly indicate that neuronal survival and proliferation are regulated by soluble factors produced by astroglia. 5. We also postulated that the neurite-promoting effect of astroglia is mediated by cell-cell contact. 6. This idea was confirmed by the finding that neurite extension was enhanced when the neurons were cultured directly on heat-treated astroglia. 7. The neurite-promoting effect was found to be specific to astroglia. 8. We preliminarily characterized the astroglial surface neurite-promoting factors (ASNPFs). 9. The relationship of laminin to ASNPFs was examined by using antibody to laminin. Laminin antibody did not inhibit the ASNPF activity. 10. The effect of digestion of heat-treated astroglia with enzymes (sialidase and endo-beta-galactosidase) on the ASNPF activity was also examined. 11. These enzyme treatments did not inhibit the ASNPF activity. 12. These results suggest that enhancement of the neurite-promoting activity is not associated with the sugar moiety of ASNPFs.

Animals↗
PubMed1991

Intracranial reconstruction of the facial nerve. Clinical observation.

Nine cases of intracranial facial nerve reconstruction are reviewed in this paper. All patients underwent this procedure for severe injury or disruption of the facial nerve during surgery for acoustic neruroma through the modified extended middle cranial fossa approach (1). Satisfactory recovery of facial function was obtained in 4 patients. Three patients underwent hypoglossal-facial nerve anastomosis 1.3-1.5 years later for no or poor recovery of the facial function. One patient refused any further surgical treatment despite unsatisfactory recovery. The remaining 1 patient, during a telephone interview, stated that facial function had not returned at all 1 year and 5 months postoperatively. Although some degree of associated movement or mass movement was unavoidable, facial movement and mimetic facial expression were better in the patients with satisfactory recovery, as compared with those after hypoglossal-facial nerve anastomosis (2). Fibrin glue, which we used in the latest 3 cases instead of suture, seemed to possibly solve the technical difficulty in placing a suture. Facial function after intracranial reconstruction with fibrin glue was as good or better than that after repair by suturing.

Adult↗
PubMed1991

Anterior transpetrosal-transtentorial approach for sphenopetroclival meningiomas: surgical method and results in 10 patients.

This report presents a new surgical method and the results in 10 patients with petroclival meningiomas extending into the parasellar region (sphenopetroclival meningiomas). Minimal but effective extradural resection of the anterior petrous bone via a middle fossa craniotomy offered a direct view of the clival area with preservation of the temporal bridging veins and cochlear organs. The dural incision was extended anteriorly to Meckel's cave, and in cases with invasion of the cavernous sinus, Parkinson's triangle was enlarged by mobilization of the trigeminal nerve. This approach offered an excellent view from the mid-clivus to the cavernous sinus. Extra-as well as intradural tumor masses and dural attachments could be cleared under direct view of the pontine surface. The risk of injury to the lower cranial nerve and of retraction damage to the temporal lobe and brain stem were kept minimal by this approach. Total tumor resection was achieved in 7 patients, with no resultant mortality. Eight patients had a satisfactory postsurgical course, extraocular paresis being their main complaint. The extent of tumor resection depended on the degree of tumor adhesion to the carotid artery, and operative morbidity on the degree of tumor invasion of the brain stem. Of the 3 patients in whom subtotal tumor removal was achieved, only one experienced regrowth of the tumor and underwent a second operation during the follow-up period (6 months-6 years).

Adult↗
PubMed1990

Tetrahydrobiopterin-dependent production of L-dopa in NRK fibroblasts transfected with tyrosine hydroxylase cDNA: future use for intracerebral grafting.

In the present study, tyrosine hydroxylase (TH; EC 1.14.16.2) cDNA was transfected into cultured fibroblasts and the production of L-3,4-dihydroxyphenylalanine (L-DOPA) was determined. Type 2 TH cDNA was transfected into fibroblasts (NRK-49F) derived from the normal rat kidney, and the expression of the TH minigene was screened by immunocytochemical staining and immunoblotting analysis with TH antiserum. Several clones of the NRK transfectants that produce TH molecules were obtained. The expressed TH molecules showed high enzyme activity in a complete assay system in vitro. However, L-DOPA was not detected in the cultured cells due to the possible absence of de novo synthesis of (6R)-L-erythro-tetrahydrobiopterin (BH4) in these cells. When BH4 was added to the medium, a large amount of L-DOPA was detected not only in the cells but also in the medium. These findings may aid in regulating the amount of L-DOPA secretion from cells after they are transplanted into the brain.

Animals↗
PubMed1990

In vivo measurement of intra- and extracellular space of brain tissue by electrical impedance method.

An impedance method was applied to evaluate transcellular fluid shifts in ischaemic brain oedema. The admittances (apparent electrical conductivities) of tissues were measured at varied frequencies based on a simple model of an electrical equivalent circuit for tissues, which consisted of Re (resistivity of extracellular fluid), Ri (resistivity of intracellular fluid) and Cm (capacitance of cell membrane). Calculated were Re, Ri, Rinf (resistivity of total fluid), Re/Ri and alpha (Cole-Cole distribution index) of brain tissue by Cole-Cole an arc of a circle. During ischaemia induced by cat middle cerebral artery occlusion (MCAO), the parameters were examined continuously. After MCAO, cerebral blood flow (CBF) decreased to under 10 ml/100 g/min. Then Re and Re/Ri increased, but Ri decreased. These results indicated that fluid shift from extracellular (EC) to intracellular (IC) space occurred after ischaemic insult. Rinf showed no changes during ischaemia of 30 min, which demonstrated no changes of total fluid volume. Using this impedance technique, fluid accumulation and shift may be examined by changes of Re, Ri, Re/Ri and Rinf in various types of brain oedema in vivo.

Animals↗
PubMed1990

Xenogeneic neural transplantation: role of vasculature and MHC antigen in immunological rejection.

The reconstruction of blood vessels in a graft is one of the important events inducing immunological rejection. First, we investigated the reconstruction of blood vessels in a graft by using a monoclonal antibody against mouse endothelial surface antigen 1. Secondly, the lymphocyte proliferative response to Ia antigen were examined in mixed lymphocyte cultures by using monoclonal antibodies against Ia antigen. The results show that the blood vessels originating in the host tissue inoculate with those originating in the donor graft tissue and that the expression of Ia antigen on the vascular endothelial cells plays an important role in the immunological rejection through sensitization of peripheral lymphocytes.

Animals↗
PubMed1990

Ceruminoma with intracranial invasion--case report.

Ceruminous gland tumors (ceruminomas), which usually involve the external auditory canal, are rare. A case of ceruminoma invading the temporal bone and histologically proven to be papillary adenoma is presented. The tumor recurred and invaded intracranially after subtotal removal and was finally diagnosed as adenocarcinoma. The importance of early diagnosis and radical treatment is stressed.

Adenocarcinoma↗
PubMed1990

Mixed pituitary adenoma and gangliocytoma associated with acromegaly--case report.

A gangliocytoma in the sellar region is very rare. We report a case of an intrasellar gangliocytoma complicated by pituitary adenoma presenting with acromegaly. A 52-year-old female was admitted to our hospital with headache, mild acromegaly, and bitemporal hemianopsia, and endocrinological study found a high serum level of growth hormone (GH). A computed tomographic scan revealed a tumor in the sellar region, which was almost totally removed by trans-sphenoidal surgery. Histological examination of the resected specimen showed diffuse, chromophobe-type pituitary adenoma, partially containing cholesterin clefts. Areas of clusters of dysmorphic neurons, adjacent to or mixed with pituitary adenoma, were diagnosed as gangliocytoma. The immunohistochemical examination showed GH-releasing hormone (GRH)-positive dysmorphic neurons and GH-positive pituitary adenoma. We consider that the trophic effect of GRH secreted by the neurons of GRH-producing intrasellar gangliocytoma probably caused the GH-producing pituitary adenoma.

Acromegaly↗
PubMed1989

Mosaic reconstruction of blood vessels in mouse neocortical tissue transplanted into the third ventricle of rat brain.

Newborn mouse neocortical tissue was transplanted into the third ventricle of rat brain and the reconstruction and the origin of the blood vessels were investigated by using a monoclonal antibody against mouse endothelial surface antigen-1 (MESA-1). It was clearly demonstrated that some of the blood vessels in the graft originated in the donor mouse neocortical tissue. An India ink perfusion experiment revealed that the blood was supplied to the MESA-1-positive blood vessels. Furthermore, electron microscopic immunohistochemical studies demonstrated the existence of a mosaic reconstruction of blood vessels which consisted of mouse- and rat-derived vascular endothelial cells. It was concluded that the blood vessels originating in the donor tissue and those originating in the host tissue inoculate with each other in the grafted tissue.

Animals↗
PubMed1989

Expression of Ia antigen on vascular endothelial cells in mouse cerebral tissue grafted into the third ventricle of rat brain.

The mechanisms of the immunological rejection after xenogeneic neural transplantation were investigated with special reference to the expression of class II major histocompatibility complex (MHC) antigen (Ia antigen) on the grafted tissue. Tissue from a newborn mouse cerebral cortex was transplanted into the third ventricle of a 4-week-old rat brain. Infiltration of cytotoxic T-cells into the grafted tissue was investigated immunohistochemically by using a monoclonal antibody (OX-8). The infiltration began 8 days after transplantation and continued until about 4 weeks when the tissue was completely rejected. The expression of Ia antigen was also investigated immunohistochemically. The Ia antigen was first detected in the grafted tissue at 6 days after transplantation. The Ia antigen was considered to be expressed on the vascular endothelial cells judging from the staining patterns and the location of India ink which was perfused from the host's left cardiac ventricle. The perfusion experiments with India ink also revealed that blood was supplied to the grafted tissue from 5 days after transplantation. These results suggest that the expression of Ia antigen on the vascular endothelial cells renders the grafted tissues competent to initiate and participate in the immune reaction. The results also raise a possibility that the expression of Ia antigen is triggered by blood supplied from the host brain. In addition, the results indicate that the Ia-positive blood vessels do not originate in the host brain but are intrinsic to the grafted tissue.

Animals↗
PubMed1989

Radical surgery of a galenic aneurysm with regional cerebral blood flow analysis. A case report.

Successful surgical treatment of a case of aneurysm of the vein of Galen is presented. An 11-month-old boy was admitted with episodes of convulsive attacks. Neuroradiological examination revealed an aneurysm of the vein of Galen filled by branches of posterior cerebral arteries and left thalamoperforating artery. Regional cerebral blood flow, which was measured by a method of xenon-enhanced computed tomography, showed a low flow area in the frontal and occipital regions. The aneurysm was approached through the bilateral parietooccipital interhemisphere, freed from the feeders, and ligated. During the operation, cortical blood flow was monitored for prevention of normal perfusion pressure breakthrough. After the feeders were successfully clipped, the blood flow increased and became normalized in the related cortex. There was no postoperative neurological deterioration.

Arteriovenous Fistula↗