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Biomedical subjects

A Nishimoto

Publications and source records attributed to A Nishimoto.

At least 55 records · Page 3Linked to original sources
PubMed1990

[Adrenal medullary graft induces recovery of the host nigrostriatal dopaminergic system in MPTP-induced mouse model of Parkinson's disease].

C57BL/6 mice show decreased dopaminergic fibers and dopamine concentration in the striatum following systemic injection of 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP). We have investigated the effect of adrenal medullary grafts into the striatum of young mice treated with MPTP. Enhanced recovery of the host nigrostriatal dopaminergic system was observed in those adrenal medullary grafted mice. However, this recovery was influenced by the survivability of grafted chromaffin cells and adrenal chromaffin cells from younger donors survived better than those from older donors. Since adrenal chromaffin cells contain several kinds of neurotrophic factors such as basic fibroblast growth factor and gangliosides, survivability of those grafted chromaffin cells may play an important role concerning recovery of the host intrinsic dopaminergic fibers. Adrenal medullary grafts to the patients with Parkinson's disease are currently under way in a large number of hospitals and we suggest more consideration be given to methods which lead to enhance the grafted chromaffin cell survival, since those survivability might be closely related to the functional recovery of these patients.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1990

[Interstitial brachytherapy for malignant gliomas using the Brown-Roberts-Wells (BRW) stereotactic system].

Eleven patients harboring recurrent or deep-seated malignant gliomas were treated by interstitial brachytherapy with 192Ir seed assembly, between June 1987 and September 1989. Implantations for the afterloaded catheter were performed using the Brown-Roberts-Wells (BRW) CT guided stereotactic system. The number of seeds and the distribution of the implants were chosen in such a way that the minimum tumor dose of 30-50Gy could be delivered to the surface or 1cm beyond the rim of the contrast enhancement. The radioactive sources were held in the afterloaded catheters that were removed after the desired dose had been delivered. Response to therapy was measured by serial CT scans and clinical examination. Tumor regressions were seen by CT scans made 2 or 3 months after implantation. One tumor showed complete regression (CR), four showed partial response (PR), one showed minor response (MR) and 5 showed no change (NC). Overall response rate was 54%. Six patients died 3 to 18 months following implantation, and five are still alive 7 to 27 months after implantation. No complications such as infection or hemorrhage were observed during the treatment. A patient harboring large (6.5cm in diameter) recurrent glioblastoma in the rt. parietal robe required a craniotomy due to the mass growing for one and half month after implantation, and radiation necrosis of the entire tumor mass was documented. The technique of stereotactic interstitial implantation was clinically well tolerated and easily reproducible and our preliminary results seemed encouraging. Technical improvement to achieve an adequate isodose distribution to cover the tumor volume might lead to improved survival rates.

Adolescent↗
PubMed1990

[Cerebellopontine angle lipoma: a case report].

A surgical case of lipoma in the cerebellopontine angle in a 37-year-old man is reported. Cerebellopontine angle lipomas are very rare lesions that differ from other intracranial lipomas in that they typically present slowly progressive focal symptoms identical to those in other tumors of this location. The patient's chief complaints were left hearing disturbance and dizzy spells. Computed tomography showed a very low density lesion (-99.3 Hounsfield units) with no enhancement in the left cerebellopontine angle. Magnetic resonance imaging (0.15T) was subsequently performed. The relative T1 weighted image showed a lesion of high signal intensity in the left cerebellopontine angle. The tumor was adherent to both the brainstem and the cranial nerves involved. On dissection, it was quite hemorrhagic. The tumor could only be partially resected because of the embedded cranial nerves and vascularity. The authors review the literature on this rare tumor and discuss the clinical appearance. Radiological assessment including CT and MRI and management of this lesion were also discussed.

Adult↗
PubMed1990

[The role of stimulation of the medullary reticular formation on intracranial pressure in cold injured brain].

This study was carried out to study the effect of stimulation of the reticular formation of the medulla oblongata on intracranial pressure (ICP) and cerebral blood volume (CBV) in injured brain with increased ICP. CBV was measured by the photoelectric method from the parietal lobe. Seventeen hours prior to the experiments, cold induced edema was produced to increase basal ICP. In 15 cats, electric stimulation produced temporary increases in BP, ICP and CBV and progressive intracranial hypertension was never observed (Group A). In 9 animals, progressive increases in CBV and ICP up to 50 to 100 mmHg were evoked after cessation of stimulation (Group B). Prestimulation ICP in Group B was significantly higher than that of Group A. Rapid and simultaneous increases in ICP and CBV following stimulation strongly suggested that global increments of CBV secondary to loss of cerebral vasomotor tonus were responsible for producing progressive intracranial hypertension. In Group B, the stimulation electrodes were invariably located at the area of the nucleus reticularis parvocellularis and gigantocellularis. Our experimental results show that in increased ICP a stimulated or irritable condition of the medullary reticular formation will cause acute progressive intracranial hypertension.

Animals↗
PubMed1989

[Analysis of the water-soluble protein fraction of glioma cells by two-dimensional electrophoresis].

The authors analyzed water-soluble proteins of culture human and rat glioma cells by two-dimensional polyacrylamide gel electrophoresis methods. Glioma cells were suspended in distilled water and then destroyed by freezing and thawing to obtain the water-soluble protein fraction. A modification of O'Farrell's non-equilibrium pH gradient (NEPHGE) method was used to analyze differences in protein mapping. Manabe's microscale two-dimensional electrophoresis without denaturing agents was used to detect proliferating cell nuclear antigen (PCNA/cyclin) by Western blotting. With O'Farrell's NEPHGE method and silver staining, at least 200 different polypeptides were clearly identified in each cell line. Cytoskeletal proteins, such as actin, were consistently separated in all cell lines. Marked differences in the protein map were observed between human and rat glioma cell lines, and even within the same species. Presumably, these differences are attributable to cell-biological difference in the glioma cells lines. Some proteins that were prominent in proliferating cells were scant in the protein maps of cells cultured for 24 hours in medium not containing calf serum, which suppresses cell growth. PCNA, an acidic nuclear protein that appears only in the late G1-S phase and is believed to be involved in cell proliferation, was detected by Western blotting and indirect immunostaining. Quantitative analysis of PCNA spots on the protein map appears useful in assessment of glioma cell proliferation. These results indicate that two-dimensional polyacrylamide gel electrophoresis can contribute to the understanding of the biological features of glioma cells.

Animals↗
PubMed1989

[Immunohistochemical study on distribution of transthyretin in normal human brain tissue and tumors].

Immunohistochemical examination of transthyretin (TTR), which is known to be synthesized in the epithelial cells of the choroid plexus as well as in the liver cells, was carried out on normal brain tissues and 84 human brain tumors, using a peroxidase-antiperoxidase (PAP) technique. TTR was demonstrated diffusely and strongly in the cytoplasm of normal choroid plexus cells, but not in ependyma and other tissues of normal brain. In all of 10 choroid plexus papillomas, TTR was found within the cytoplasm of tumor cells. In contrast, neither the two papillary ependymomas nor any other brain tumors contained TTR. Among the choroid plexus papillomas, some cases showed clear positive reactions in almost all tumor cells, while others had only a few TTR-positive cells. With these immunohistochemical findings, TTR proved a very useful marker of normal choroid plexus and choroid plexus papilloma.

Adult↗
PubMed1989

[Analysis of activated lymphocytes and antigen-present macrophage in human brain tumors using double immunofluorescence staining].

Twenty-eight human brain tumors (18 gliomas and 10 metastatic brain tumors) were examined immunohistochemically using anti-Leu 1, -Leu 2 a, -Leu 3a + 3b, -LeuM 5, -HLA-DR, IL-2 receptor, -HLA-ABC and Ki-67 monoclonal antibodies (MoAb). Also, in the specimens, in which Leu 1+ cells and Leu M5+ cells infiltrate, simultaneous detection of Leu 2a, Leu 3a + 3b, or Leu M5 and HLA-DR, was performed by double immunofluorescence staining to analyze the T cell activation and antigen-present macrophage (M phi). Most of low-grade gliomas with low percentage of Ki-67+ cells showed only little lymphocyte and M phi's infiltration. THEre was a tendency toward a marked degree of T cell and M phi infiltration in malignant glioma with higher percentage of Ki-67+ cells. However, in metastatic brain tumors, M phi did not tend to infiltrate. IL-2 receptor+ cells was absent in the majority of brain tumors. Tumor cells and vascular endothelial cells also expressed HLA-DR antigens. The majority of tumor cells expressed HLA-A, B, C antigens. There were no correlation among the degree of T cell and M phi infiltration, MHC antigen expression, and percentage of Ki-67+ cells. Double immunofluorescence staining demonstrated that 42.4% of Leu 2a+ cells, 34.7% of Leu3a+ + 3b+ cells and 32.7% of M5+ cells are HLA-DR positive in glioma, and that 50.2% of Leu2a+ cells, 59.4% of Leu3a + 3b+ cells and 67.3% of LeuM5+ cells are HLA-DR positive in metastatic brain tumors.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗
PubMed1989

[A case of vacuolated meningioma].

A rare case of falx meningioma with extensive vacuolization was reported. A 57-year-old woman was admitted to Okayama University Hospital because of numbness in her left lower limb. A plain CT scan showed a hypodense mass in the right frontal region with marked enhancement after contrast medium injection. MRI on T1 weighted images showed low intense mass with the so-called "peritumoral band" of low intensity at the periphery of the mass. Angiogram showed a mass effect and a tumor stain fed by the right pericallosal artery and left middle meningeal artery. The mass was excised en bloc. Microscopic examination demonstrated tumor cells with varied sized vacuoles, which were mostly fat-negative, except for small islands with typical meningothelial cells in the periphery of the tumor. Ultrastructurally, there were two kinds of vacuole in the tumor cells. The smaller, round vacuoles were in the cytoplasm, while the larger ones were in the extracellular space. The cell processes had developed junctional complex, and numerous cytoplasmic filaments were evident. With these findings, this mass was diagnosed as vacuolated meningioma. It is important especially in frozen section not to misdiagnose the tumor as liposarcoma, chordoma, metastatic brain tumor and so on.

Cerebral Angiography↗
PubMed1988

Intraparenchymal allografts in the mouse brain in relation to immunocytochemical identification of T lymphocyte subsets.

In a study of intracerebellar allografts of mice brainstem anlagen (embryonic day 12-14), we examined immunocytochemically the expression of two different types of T lymphocytes in and around the grafts. Helper/inducer and cytotoxic/suppressor T cells were identified with anti-L3T4 and anti-Lyt-2 monoclonal antibodies, respectively. Allografts into major histocompatibility complex (MHC)-compatible recipients showed no histological signs of rejection such as marked neovascularization and cellular infiltrates even 6 months after transplantation, but those into MHC-incompatible recipients generally had rejection reactions within one month after transplantation. In the latter cases, the L3T4/Lyt-2 ratio for the T lymphocytes in the infiltrates of the grafts was 1.03 +/- 0.14 (mean +/- S.D.), suggesting that both helper/inducer and cytotoxic/suppressor T cells may play important roles in the mediation of intraparenchymal brain allograft rejection.

Animals↗
PubMed1988

Stimulation of internal capsule, thalamic sensory nucleus (VPM) and cerebral cortex inhibited deafferentation hyperactivity provoked after gasserian ganglionectomy in cat.

Facilitation of the opiate-mediated system provides relief of excess pain but not of deafferentation pain. Influence on neuronal hyper-activity, which was provoked after the deafferentation of the peripheral trigeminal nerve (deafferentation hyperactivity; DH), by stimulation of the internal capsule (IC), VPM nucleus of the thalamus and by the cerebral sensorimotor cortex, was examined. This experiment demonstrates that a suppressive effect is exerted on the sustained neuronal hyperactivity, which was proved to have a close relationship with deafferentation pain. In the preliminary experiment, it was confirmed that DH was provoked by coagulation of unilateral (left side) Gasserian ganglion in 29 adult cats, who were allowed to survive up to 72 days. DH, sustained high amplitude discharge without any stimuli on the face or neck, was detected in the subnucleus caudalis of the spinal trigeminal nucleus (STNcd) of the denervated side. DH was never suppressed by facilitation of the opiate-mediated system. 87 of 113 neurones identified in the STNcd of the denervated side showed DH in another 18 cats. In 30 of 55 neurones examined, DH was conspicuously suppressed by the stimulation of contralateral (right) side, 11 of 29 neurones by ipsilateral IC. Five of 13 neurones were suppressed by contralateral VPM stimulation, 2 of 3 neurones by ipsilateral stimulation. Stimulation of cortical area, SM1 of MS1, in other 15 cats, considerably suppressed DH in STNcd. Microinjection of wheat-germ-agglutinin in the cerebral cortex revealed in direct projection of the descending fibre from MS1 to STNcd and brain stem reticular formation via IC.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1988

The effect of intravenous lidocaine on experimental brain edema and neural activities.

A series of experiments was conducted to clarify the effect of intravenous administration of lidocaine on brain water content, local cerebral blood flow (lCBF), and neural recovery in brain injury induced by exposure of the cat's cerebral surface to the air. The injury produced ischemia and edema in the cortex and white matter without direct damage of the cortex. Lidocaine (3.0 mg/kg) was given intravenously for 30 minutes immediately after air exposure and thereafter at the rate of 2 mg/kg/hour. Twelve hours after exposure, lidocaine significantly suppressed cortical ischemia and edema; however, it had no effects in the white matter. The electrophysiologic activities of the cortex and white matter which were assessed by the direct cortical response and somatosensory evoked response were significantly preserved by lidocaine compared with nontreated animals. The results of this experiment demonstrate that intravenous lidocaine has a significant beneficial effect on cortical ischemia and electrophysiologic activities of the cortex and white matter in injured brain.

Animals↗
PubMed1988

Elastosis in meningioma. A case report and electron microscopic study.

A 55-year-old man underwent left frontoparietal craniotomy for total removal of a parasagittal meningioma. The tumor showed a predominant pattern of meningotheliomatous meningioma and a partial pattern of angiomatous, transitional and fibrous meningioma. A striking feature was the appearance of unusually numerous elastinophilic material in the intercellular stroma. We observed a process in which the progress of elastosis changed the appearance of meningotheliomatous meningioma to a hypocellular, and subsequently acellular fibroelastotic node. Three years after the first craniotomy, meningioma recurred at the same site. The recurrent tumor also showed the histological pattern of meningotheliomatous meningioma with stromal elastosis, as previously observed. This is the first report of a case of meningioma with stromal elastosis. The present case represents the first unequivocal demonstration of elastogenesis in meningioma.

Elastic Tissue↗
PubMed1988

Hyperthermia for brain tumors: improved delivery with a new cooling system.

Hyperthermia has emerged as an adjunct to other forms of brain tumor therapy. Interstitial microwave irradiation is an effective method of inducing localized brain hyperthermia. One of the problems with this technique, however, is the overheating of tissue adjacent to the antenna. In this study, a cooling system for the interstitial microwave antenna was developed for the purpose of providing uniform and accurate heating by the elimination of overheating. The ability to generate more uniform hyperthermic fields was evaluated in normal monkey brains. Six monkeys under general anesthesia and controlled respiration underwent parietooccipital craniectomies 4 x 4 cm in size. The antenna cooling system was constructed of a silicone tube 5.0 mm in outer diameter. Silicone-coated interstitial microwave antennae 1.5 mm in diameter were used. A single antenna or a square array (1.6 cm on a side) of 4 antennae was inserted into the brain with the coupled system to a depth of 2 cm. The brain tissue was heated by 2450-MHz microwave irradiation. Temperature distributions were mapped using nonperturbing thermocouples. These thermal profiles were compared with those generated without the cooling system. In the experiments with the single antenna, the antenna cooling system eliminated the overheating and rapid radial falloff in temperature, without a reduction of the hyperthermic field. In the four-antennae experiments using the cooling system, the thermal field was dramatically flattened with minimal reduction in size; however, the area maintained at a therapeutic temperature range (42-45 degrees C) was significantly enlarged by the cooling system.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

[Early diagnosis of metastatic brain tumor].

For the early diagnosis of metastatic brain tumor, careful and long-term follow-up is important when the primary tumor has already been found. Metastatic brain tumor should be suspected whenever neurological symptoms develop in such a patient. In the cases of lung cancer or lung metastases, CT scan of brain should be taken even if the patients have no neurological symptoms, because lung cancer frequently metastasizes to the brain and other cancers metastasize to the brain via the lung. When the primary sites are unknown, primary brain tumors should be distinguished. Relatively rapid progression of symptoms including mental disturbance, multiple lesions on CT scan, lesions on chest X ray film, careful cerebral angiogram and MRI are helpful for the differential diagnosis.

Biomarkers, Tumor↗
PubMed1988

[A rare case of cerebral aspergillus aneurysm at the site of temporary clip application].

Anterior communicating artery aneurysm was shown in a 48-year-old man who had suffered from subarachnoid hemorrhage (SAH) by cerebral angiography. Right pterional approach was performed on the 40th day after SAH. Premature ruptured occurred during aneurysmal manipulation and temporary clip (Scoville clip) was placed at the middle of the right A1 segment for fifteen minutes. the anterior communicating artery aneurysm was successfully clipped and postoperative course was uneventful. But, four days after the operation, the patient fell into coma following generalized tonic convulsion. Lumbar puncture showed fresh SAH. Consciousness recovered gradually to a lethargic state. A newly formed berry aneurysm was revealed on the righ A1 segment at the site of the temporary clip application by cerebral angiography performed on the seventh day after aneurysmal surgery. Second attack occurred on the 12th postoperative day and the patient died on the 16th day after the operation. Postmortem findings disclosed massive subarachnoid and intraventricular hemorrhage from the ruptured aneurysm at the right A1 segment. Microscopic examination of the aneurysm and the right A1 segment. microscopic examination of the aneurysm and the right A1 segment showed the extensive destruction of the artery and massive proliferation of aspergillus in the arterial wall which was prominent of its outer layer. The mechanism of the formation of the new aneurysm in this case was considered as follows: the arterial wall was primarily damaged by the temporary clip and was weakened rapidly by the invasion of aspergillus, probably producing thrombosis of the vast vasorum, hemorrhage, and necrosis in it.

Aneurysm, Infected↗