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Biomedical subjects

S Toya

Publications and source records attributed to S Toya.

At least 127 records · Page 7Linked to original sources
PubMed1987

Immunohistochemical studies on synapse formation by embryonic cerebellar tissue transplanted into the cerebellum of the weaver mutant mouse.

Normal cerebellar tissue, obtained from 15-day-old CBA/JNCij mouse embryos, was transplanted into the cerebellum of 4-week-old weaver mice. At the 6th week after the transplantation, the grafted tissue was distinguishable from the host cerebellum, developing a trilaminar organization. The formation of synapses by the implanted granule cells was analyzed immunohistochemically with antiserum against synaptic vesicle protein, Synapsin I. Some areas in the host cerebellum as well as in the grafted tissue were intensely stained by anti-Synapsin I serum, suggesting that the implanted granule cells make synaptic contacts with the neuronal cells.

Animals↗
PubMed1987

[Monitoring of antidromic facial nerve action potentials in cerebello-pontine angle tumor operations].

A method of recording the antidromic facial nerve compound potential (AFNAP) is presented. When the facial nerve is stimulated, a compound action potential is propagated in both directions from the stimulating site. We recorded AFNAP's in 6 cases of cerebello-pontine angle (CP angle) tumors (5 acoustic neuromas and one epidermoid) using a bipolar silver ball-type electrode directly put on the facial nerve in CP angle by stimulation of the peripheral facial nerve at the stylomastoid foramen. It was necessary to use needle electrodes instead of surface ones for stimulation to keep the artefacts from stimulating currents within reasonable bounds. Good contact of the electrode tips with facial nerve was required to get clear action potential. By stimulation with needle electrodes AFNAP's were recorded without averaging and had a good reproducibility. AFNAP's were typical triphasic potentials and the major negative peak latencies were observed from 1.5 to 3.4 msec except one case of recurrent epidermoid whose major negative peak latency was 7.6 msec. It was verified that these potentials were the results of facial activity, because they were recorded exclusively on the facial nerve, they could not be recorded at the proximal end of the sectioned facial nerve, and alterations of latency were observed with changing the position of recording electrode along the facial nerve. A calculated conduction velocity was about 50 m/sec. It was thought that recording AFNAP facilitated the identification of the facial nerve on the surface of the CP angle tumor, because the amplitude of AFNAP decreased immediately when the recording electrodes were off from the facial nerve.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1987

[Basal skull metastasis of stomach cancer presenting with Garcin's syndrome--a case report].

A case of 57-year-old man with Garcin's syndrome is reported. By means of upper gastrointestinal endoscopy, this patient proved to have a stomach cancer. He noticed left trigeminal neuralgia for the first time in early Jan. 1986, and when he was referred to our department, his symptoms and signs of left cranial nerve palsy (from 5th to 12th, totally 8 nerves) were complete, although other neurological findings such as long tract signs, cerebellar signs, or papilledema were all negative. Although skull X-ray and basal skull tomography revealed neither bony deformity nor destruction, CT scan and angiography showed suspicious appearance of basal skull invasion of a certain mass. CSF examination revealed no malignant cells or abnormal protein, and sugar content. Exploratory craniotomy for tumor biopsy was performed. Histologically, the tumor had characteristics of anaplastic carcinoma. General survey revealed that he had a stomach cancer which was histologically the same as the basal skull tumor. His general condition became so serious that irradiation to the lesion was not indicated Among many papers reported about Garcin's syndrome, those of basal skull metastasis of stomach cancer are extremely rare. The authors discussed the lesion in comparison with meningeal carcinomatosis involving cranial nerves.

Carcinoma↗
PubMed1986

Subcultured astrocytes suppress the proliferation of neuroblasts in vitro.

The effects of subcultured astrocytes on the proliferation of neuronal precursor cells (neuroblasts) from rat embryonic cerebral hemispheres were examined. The survivability of neurons and the neurite outgrowth were significantly enhanced by the subcultured astrocytes compared to those of neurons plated on poly-L-lysine-coated coverslips. The incorporation of [3H]thymidine into neuroblasts was remarkably suppressed by the subcultured astrocytes indicating that the astrocytes inhibit the proliferation of neuroblasts. These results suggest that astrocytes enhance the maturation of neuroblasts possibly via either cell-cell contact or trophic substances.

Animals↗
PubMed1986

Possible association of platelet-derived growth factor (PDGF) with the appearance of reactive astrocytes following brain injury in situ.

The association of platelet-derived growth factor (PDGF) with the appearance of reactive astrocytes following injury was investigated by using a specific antagonist of PDGF, Trapidil. The cerebral cortex of 4-week-old male rats was unilaterally injured with a 22-gauge needle. Immunohistochemical staining with antiserum to glial fibrillary acidic protein revealed that reactive astrocytes had increased in number around the wound by 2 days following the injury and had spread to the ipsilateral areas distant from the wound by 3 days. The appearance of reactive astrocytes in areas distant from the wound was dramatically suppressed by the administration of Trapidil. This finding indicates that PDGF might play a role in gliosis following injury.

Animals↗
PubMed1986

Septal deafferentation enhances the neurotrophic effects of rat hippocampus on cultured neural cells from the central nervous system.

Neurotrophic effects (NTEs) of various brain regions of 4-week-old rats were examined in primary culture of rat embryonic cerebral hemispheres. Extracts of the hippocampus, brainstem and septal nucleus highly enhanced the survivability of neuronal cells and the division of non-neuronal cells by 9 days. The septohippocampal tract (fimbria fornix) was cut and the effect on the neurotrophic activity in the hippocampus was examined. The NTEs of hippocampal extracts remained unchanged 3 days after septal deafferentation, was significantly increased by 7 days, peaked at 14 days and returned to the basal level by 21 days.

Animals↗
PubMed1986

Transplantation of bulk-separated oligodendrocytes into the brains of shiverer mutant mice: immunohistochemical and electron microscopic studies on the myelination.

Normal oligodendrocytes were separated from 7-day-old mouse (BALB/c) brains by the Percoll gradient method. Immunohistochemical staining with an anti-galactocerebroside serum revealed that about 85% of the separated cells were oligodendrocytes. The oligodendrocytes were transplanted into the corpus striatum of 4-week-old shiverer mutant mice which are characterized by the lack of myelin basic protein (MBP). Myelination by the implanted oligodendrocytes was investigated immunohistochemically and electron microscopically 6 weeks after the operation. Certain areas in the corpus striatum were intensely stained with antiserum to MBP. Electron microscopic examination showed that some axons were surrounded by normal type myelin sheaths with major dense lines. These results clearly indicate that matured oligodendrocytes are able to survive and myelinate the host axons even in the adult brain.

Animals↗
PubMed1986

The effect of arcuate nucleus transplantation on the development of the anterior pituitary in monosodium glutamate-treated rats.

Treatment with monosodium glutamate (MSG) during the neonatal period is known to produce a selective lesion of the arcuate nucleus in rat brain, which is the major site of production of growth hormone releasing-hormone (GRH), followed by a secondary reduction in growth hormone (GH) synthesis in the anterior pituitary. Normal arcuate nuclei from hypothalamic areas of newborn rats were transplanted into the third ventricles of 27-day-old rats which were treated with MSG on alternate days for the first 10 days of life. Ninety days after birth, the anterior pituitaries were examined for GH synthesis by immunohistochemical staining with GH antiserum. The results indicated that the impaired GH synthesis in the anterior pituitary treated with MSG was partially restored in some recipients by grafts of arcuate nuclei in which the GRH-containing neurons were clearly detected by immunohistochemical staining with GRH antiserum.

Animals↗
PubMed1986

Results of surgery by the modified extended middle cranial fossa approach in 100 patients with acoustic neuroma.

The results of surgery by the middle cranial fossa (MCF) approach or the modified extended MCF approach in 100 patients with acoustic neuroma are reported. The rates of facial nerve preservation, tumor removal, and hearing preservation were reported and discussed. This surgical procedure can be applied to tumors of any size, from tumors confined to the internal auditory canal to those extending into the posterior fossa.

Adult↗
PubMed1986

Facial nerve function after surgery for removal of acoustic neuroma by the extended middle cranial fossa approach.

Postoperative facial nerve function was evaluated in 98 patients operated on by the middle cranial fossa approach or the extended middle cranial fossa approach from June 1976 to April 1985. In this series, the smaller the tumor size at the time of the initial surgery, the better the postoperative facial nerve function was. The facial nerve was preserved in 83.4% of the 79 patients who were subjected only to the initial surgery. However, total removal of the tumor along with facial nerve preservation was achieved only in 70.8%. Anatomical preservation of the facial nerve was possible in 78% of 87 patients. The postoperative functional results among patients in whom facial nerves were anatomically preserved were satisfactory (facial expression score of 75% or higher, i.e., 30 points or more out of a possible 40 points) in 70-80% of the patients with small size or intracanalicular tumors, but, in less than 50% of the patients with tumors of medium size or larger. There is a need to obtain higher rates of functional preservation as well as higher rates of satisfactory functional results. At the present stage, we must strive to achieve earlier diagnosis so that surgery can be performed while the tumor is still medium-sized or small.

Adult↗
PubMed1986

Echocardiographic detection and treatment of intraoperative air embolism.

A real-time two-dimensional echocardiogram was used to detect the presence of an air embolism in patients undergoing neurosurgical procedures in the sitting position. The technique could with good sensitivity detect the appearance of a single air bubble intraoperatively, thus allowing early intervention to prevent development of further air emboli. Two types of air embolism could be differentiated; the single-bubble type and the "stormy-bubble" type. The single-bubble type was observed during skin and muscle incisions, craniotomy, and brain lesion excision. Further embolism development was prevented by electrocoagulation and application of bone wax. The stormy-bubble type occurred during dura and muscle incisions and was prevented by electrocoagulation, reflection of the dura, or suturing the affected muscle. The routine use of a Swan-Ganz catheter for removal of air embolism by suction proved effective for the treatment of the stormy-bubble type of air embolism. Masking the operative field with saline-soaked cotton strips was of moderate benefit in the stabilization of the single-bubble type of air influx, but proved to be of little value in controlling the entrance of the stormy-bubble type.

Echocardiography↗
PubMed1985

Immunohistochemical detection of the gene product of Rous sarcoma virus in human brain tumors.

We have studied 108 cases of brain tumors by immunohistochemical staining utilizing an antiserum against the src gene product and GFA protein in order to elucidate the relationship between the brain tumors and the transforming genes. While the normal human brain tissues were not positive with the antiserum against the src gene product, several astrocytomas were clearly positive and other brain tumors were negative with the same. Src-gene product related peptide was detected in some of the human astrocytomas.

Astrocytoma↗
PubMed1985

Immunohistochemical studies on mouse cerebral cortex grafted into the third ventricle of rats treated with cyclosporin A.

Newborn mouse cerebral cortex was transplanted into the third ventricle of an adult rat brain. After the operation, the immunosuppressant cyclosporin A was administered daily for two weeks, and the grafted tissue was examined immunohistochemically at the 4th week. Neurons, astroglias and oligodendroglias were positively stained by antibodies against neurofilament, glial fibrillary acid protein and 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase), respectively. The CNPase staining indicated that myelination had occurred in the grafted tissue. Thus both neuronal and glial elements in the grafted tissue could survive and mature in the third ventricle of the different species upon administration of cyclosporin A.

Animals↗