Yasuhiko Hayashi

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OBJECTIVES Hemangiopericytomas (HPCs) are rare neoplasms with relatively high rates of recurrence and extracranial metastasis. Though the differential diagnoses from angiomatous meningiomas and from solitary fibrous tumors (SFTs) are both important, the latter diagnosis is somewhat more important in light of the benign prognosis of SFTs and the difficulties(More)
OBJECT Fluorescence-guided surgery using 5-aminolevulinic acid (5-ALA) has been broadly recognized as a beneficial tool for the resection of glioblastoma multiforme (GBM). Fluorescence in the ventricular walls, which were apparently free of macroscopic tumor or MR imaging enhancement indicative of CSF dissemination, was detected during surgery for GBM. To(More)
Glioblastoma multiformes (GBMs) express increased aquaporin (AQP) 1 compared to normal brain. AQPs may contribute to edema, cell motility, and shuttling of H(2)O and H(+) from intracellular to extracellular space. We sought to gain insight into AQP1 function in GBM. In cultured 9L gliosarcoma cells, AQP1 expression was induced by dexamethasone,(More)
Although there are many reports on the clinical use of the MIB-1 labeling index (LI), which is a measure of proliferative activity in astrocytomas; its significance varies between studies. There are no known molecules that are directly linked to the MIB-1 LI in astrocytomas. We evaluated the clinical value of the MIB-1 LI in our human glioblastoma cases and(More)
BACKGROUND Arachnoid cysts (ACs) are congenital anomalies of the central nervous system and arise in virtually all locations where the arachnoid membrane exists. Posterior fossa ACs are considered to develop in the posterior aspect of the rhombencephalic roof plate and do not communicate freely with the fourth ventricle or perimedullary subarachnoid space.(More)
High-grade (World Health Organization grades II and III) meningiomas grow aggressively and recur frequently, resulting in a poor prognosis. Assessment of tumor malignancy before treatment initiation is important. We attempted to determine predictive factors for high-grade meningioma on magnetic resonance (MR) imaging before surgery. We reviewed 65(More)
Roquefortine, a cyclopeptide derived from the diketopiperazine cyclo(Trp-dehydroHis), is a secondary metabolite produced by several Penicillium species. It has been reported to cause neurotoxic effect and to inhibit Gram-positive bacteria growth. The mechanisms responsible for its toxicity and metabolism are still unknown. In this study, we investigated the(More)
OBJECTIVE To investigate in vitro cytotoxicity and oxidative stress response induced by multiwalled carbon nanotubes (MWCNTs). METHODS Cultured macrophages (murine RAW264.7 cells) and alveolar epithelium cells type II (human A549 lung cells) were exposed to the blank control, DNA salt control, and the MWCNTs suspensions at 2.5, 10, 25, and 100 μg/mL for(More)
Sphingosine-1-phosphate (S1P) is a bioactive lipid that signals through a family of G protein-coupled receptors consisting of 5 members termed S1P(1-5), and it regulates cellular proliferation, migration and survival. We investigated the expression and role of S1P receptors in glioma. Human glioma expressed S1P(1), S1P(2), S1P(3), and S1P(5) by quantitative(More)
A 55-year-old man was admitted to our hospital complaining of left hemiparesis. Magnetic resonance imaging (MRI) showed a smooth ring-like enhanced cystic tumor in the right parietal lobe. He underwent gross total resection of the tumor under neuronavigation and 5-aminolevulinic acid (5-ALA) fluorescence guiding method. Histopathological examination of the(More)