Yuichi Sato

Iwate Medical University, Morioka-shi, Iwate-ken, Japan

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Publications (5)8.9 Total impact

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    ABSTRACT: BACKGROUND: We report a case of an uncommon association of pituitary adenoma with neuronal choristoma that usually is diagnosed at initial surgery. CASE DESCRIPTION: A 50-year-old woman with acromegaly and bitemporal hemianopsia underwent removal of a pituitary adenoma via the transsphenoidal approach. Histologic examination of the first surgical specimen demonstrated only adenoma, which was eosinophilic and expressed growth hormone. Fourteen years later, bitemporal hemianopsia recurred, and magnetic resonance imaging revealed regrowth of the residual tumor. DISCUSSION: The patient underwent removal of the regrown tumor via the transsphenoidal approach. Histologic examination of the second surgical specimen revealed gangliocytoma and a small component of pituitary adenoma. CONCLUSIONS: The present case report supports the theory that pituitary adenoma with neuronal choristoma might represent the result of neuronal differentiation from pituitary adenoma.
    World Neurosurgery 06/2012; · 1.77 Impact Factor
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    ABSTRACT: Phosphorylation of histone H2AX is a sensitive marker of DNA damage, particularly of DNA double strand breaks. Using multiparameter cytometry we explored effects of etoposide and temozolomide (TMZ) on three glioblastoma cell lines with different p53 status (A172, T98G, YKG-1) and on normal human astrocytes (NHA) correlating the drug-induced phosphorylated H2AX (gammaH2AX) with cell cycle phase and induction of apoptosis. Etoposide induced gammaH2AX in all phases of the cell cycle in all three glioblastoma lines and led to an arrest of T98G and YKG-1 cells in S and G(2)/M. NHA cells were arrested in G(1) with no evidence of gammaH2AX induction. A172 responded by rise in gammaH2AX throughout all phases of the cycle, arrest at the late S- to G(2)/M-phase, and appearance of senescence features: induction of p53, p21(WAF1/CIP1), p16(INK4A) and beta-galactosidase, accompanied by morphological changes typical of senescence. T98G cells showed the presence of gammaH2AX in S phase with no evidence of cell cycle arrest. A modest degree of arrest in G(1) was seen in YKG-1 cells with no rise in gammaH2AX. While frequency of apoptotic cells in all four TMZ-treated cell cultures was relatively low it is conceivable that the cells with extensive DNA damage were reproductively dead. The data show that neither the status of p53 (wild-type vs. mutated, or inhibited by pifithrin-alpha) nor the expression of O(6)-methylguanine-DNA methyltransferase significantly affected the cell response to TMZ. Because of diversity in response to TMZ between individual glioblastoma lines our data suggest that with better understanding of the mechanisms, the treatment may have to be customized to individual patients.
    Cancer biology & therapy 04/2009; 8(5):452-7. · 3.29 Impact Factor
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    ABSTRACT: A desmoplastic infantile astrocytoma (DIA) is an extremely rare tumor that comprises a solid astrocytic tumor accompanied by a large cyst and involves the superficial cerebral cortex and leptomeninges in infants. The solid part of this type of tumor has been well described in various reports and books, but characteristics of the cystic portion have remained unclear. Because adequate resection is required to ensure a favorable prognosis, information about the cyst is very important for diagnostic purposes and surgical planning. The authors report on the clinical and histological features of the cyst in a case of a DIA. A 12-month-old boy presented with vomiting. Contrast-enhanced magnetic resonance imaging revealed a strongly enhancing single-lobed large cyst located in the deep white matter, under the solid part of the tumor attached to the dura mater of the left frontal lobe. Both the solid and cystic portions of the tumor were surgically removed. The border between the cyst wall and surrounding white matter was unclear. Histologically, the cyst wall was composed of gliosis representing a rough accumulation of reactive astrocytes, lymphocytes, and small capillary vessels in edematous parenchyma, but no tumor cells. The present case and previous reports suggest that the cyst does not contain tumor cells, even if strongly depicted on contrast-enhanced neuroimaging, and that a thickly enhancing cyst wall indicates gliosis with accumulation of numerous small vessels.
    Journal of Neurosurgery Pediatrics 03/2008; 1(2):148-51. · 1.63 Impact Factor
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    ABSTRACT: A 53-year-old man presented with subarachnoid hemorrhage (SAH) in the left sylvian fissure. Preoperative computed tomography angiography revealed symmetrical aneurysms located at the bifurcations of the right and left middle cerebral arteries (MCAs). The left MCA aneurysm responsible for the SAH was clipped. The patient received post-surgical volume expansion treatment that did not induce hypertension. His systolic blood pressure ranged from 170 to 225 mmHg between the day of the first surgery and the 11th postoperative day. The postoperative course was uneventful until the 11th postoperative day when the patient suffered another SAH in the right sylvian fissure. The right MCA aneurysm was responsible for the second SAH and was clipped. The patient had multiple risk factors for rupture of concomitant unruptured aneurysm including a large, multilobed aneurysm, hypertension, smoking, and a family history of aneurysmal SAH. The present case suggests that all aneurysms should be simultaneously treated using endovascular coil embolization or several craniotomies if the patient has multiple risk factors.
    Neurologia medico-chirurgica 02/2008; 48(11):512-4. · 0.49 Impact Factor
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    ABSTRACT: Reported herein is a case of central neurocytoma with differentiation toward ganglion cells, considered to be a typical case of ganglioneurocytoma. Tumor cells of various degree of differentiation toward ganglion cells were intermingled with typical neurocytoma cells in a fibrillary background, with transition of tumor cells from typical neurocytoma cells to differentiated ganglion cells evident throughout the tumor. The tumor cell nuclei were positive for NeuN. Fine granular positivity for synaptophysin was seen in the cytoplasm of the tumor cells, and background fibrils and the cytoplasm of some ganglioid cells were positive for neurofilament. Several cases of central neurocytoma with ganglioid cells have been reported, with some diagnosed as ganglioneurocytoma. However, histopathological details and persuasive figures have been lacking. It is considered that the diagnosis of ganglioneurocytoma should be applied to tumors displaying the following characteristics: (i) clinical aspects such as location, demarcation and growth rate consistent with neurocytoma; (ii) transition between neurocytoma cells and ganglion cells; and (iii) ganglioid cells distributed throughout the tumors.
    Pathology International 01/2008; 57(12):799-803. · 1.72 Impact Factor