Keisuke Ishizawa

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Multiple system atrophy (MSA) is a neurodegenerative disorder that predominantly affects motor-related neuroanatomic structures. The role of microglia in MSA is unknown. To address this issue, we conducted quantitative image studies on the brains from 13 cases of MSA, comprising 8 cerebellar and 5 parkinsonian variants. Microglial and glial cytoplasmic(More)
Hyperphosphorylated tau (p-tau) deposition has been documented in a limited population of patients with Gerstmann-Sträussler-Scheinker syndrome (GSS) with particular point mutations of the prion protein (PrP) gene. Although its pathogenesis is only poorly understood, p-tau in GSS is known to be identical to that in Alzheimer's disease (AD). We conducted(More)
Papillary glioneuronal tumor (PGNT) is a rare and new type of glioneuronal neoplasm of the central nervous system. It is characterized by pseudopapillary structures composed of hyalinized vessels rimmed by cuboidal glial cells and the proliferation of neuronal cells. We report a peculiar PGNT arising in the parietal lobe of a 67-year-old man, which was(More)
The histogenesis of stromal cells in hemangioblastoma is inconclusive despite a long-term controversy. An immunohistochemical and ultrastructural study was conducted for 17 cases of cerebellar hemangioblastoma. A wide range of immunohistological markers, targeting epithelial, mesenchymal, endothelial and neuroectodermal tissues, was used. In all cases, the(More)
AIMS To facilitate the understanding and correct diagnosis of the anaplastic variant of pleomorphic xanthoastrocytoma (PXA). METHODS AND RESULTS Twelve cases of PXA were divided into six conventional and six anaplastic types. Three anaplastic PXAs developed in recurrent tumours and three occurred as the primary tumour. Anaplastic PXAs were microscopically(More)
To clarify the cellular composition of various peripheral nerve tumorous lesions (traumatic neuroma, 5 cases; schwannoma, 10 cases; neurofibroma, 14 cases; perineurioma, 3 cases; conventional malignant peripheral nerve sheath tumor (MPNST), 7 cases; perineurial MPNST, 4 cases), expression of several markers specific to nerve sheath cells, including glucose(More)
Subependymoma is a tumor of the central nervous system, which frequently occurs in the ventricles and rarely in the spinal cord. Most of the intraventricular subependymomas are subclinical and thus incidentally encountered at autopsy, whereas the spinal ones are inevitably accompanied by myelopathy and are often diagnosed clinically as ependymomas or(More)
1: Ebselen (2-phenyl-1,2-benzisoselenazol-3[2H]-one) is a selenoorganic compound exhibiting both glutathione peroxidase activity and antioxidant activity. Although it has been reported that ebselen is effective for oxidative stress-induced neuronal damage both in vivo and clinically, the precise mechanisms of the efficacy have not yet been elucidated. Thus,(More)
The present study was undertaken to clarify the role of histaminergic neuron system on amygdaloid kindled seizures in rats. A significant decrease in histamine contents in the amygdala was observed after development of amygdaloid kindling. Histidine and metoprine inhibited amygdaloid kindled seizures at doses causing an increase in histamine contents of the(More)