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Dive into the research topics where Masaharu Amagasa is active.

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Featured researches published by Masaharu Amagasa.


Neurosurgery | 1988

Posttraumatic dissecting aneurysm of the anterior cerebral artery: case report.

Masaharu Amagasa; So Sato; Kazunori Otabe

A case of cerebral infarction in the territory of the anterior cerebral artery after a minor head injury is reported. It is possible that direct or mechanical damage by the edge of the falx or stretching and shearing of the anterior cerebral artery after an acute shift of the corpus callosum caused the localized lesion of the left anterior cerebral artery. We think that this mechanical injury caused a dissecting aneurysm or a cerebral arterial dissection, which was diagnosed by sequential angiographic changes.


Brain Research | 1989

Actions of brain-protecting substances against both oxygen and and glucose deprivation in the guinea pig hippocampal neurons studies in vitro

Masaharu Amagasa; Kazuo Mizoi; Akira Ogawa; Takashi Yoshimoto

A study was made of the protective effects of several drugs (mannitol, phenytoin, vitamin E and dexamethasone) on the electrical activities of guinea pig hippocampal neurons in vitro when they were treated with a bathing medium deprived of both oxygen and glucose. Using guinea pig hippocampal slices, antidromic field potentials in the granular cell layer of the dentate gyrus were recorded stimulating mossy fibers. A model of ischemia in vivo in the slices was achieved by removing both oxygen and glucose from the perfusing medium. In standard medium, after 10 min of both oxygen and glucose deprivation, the field potentials exhibited minimum recovery with an amplitude of 6% of the control after 60 min. The protective effect of the drugs was evaluated by recovery of the field potential amplitude of the 60 min post-deprivation response and histological examination of the brain slice tissue. Drugs were added during 30 min of pre-deprivation and during deprivation. In this experiment we demonstrated that (1) phenytoin and vitamin E clearly showed protective action against neuronal damage caused by both oxygen and glucose deprivation in guinea pig hippocampal slices, (2) combined application of these drugs was more effective, and (3) mannitol showed no protective action in vitro. It was also demonstrated that (4) the dentate antidromic field response can be a useful index of cell death.


Brain Tumor Pathology | 1997

Lhermitte-Duclos disease associated with Cowden disease

Masaharu Amagasa; Fumiaki Yuda; Takahiko Tsunoda; So Sato

We encountered a patient with Lhermitte-Duclos disease accompanied by Cowden disease, the second reported in Japan. The histological findings are described in detail. It is important to suspect Cowden disease in patients with Lhermitte-Duclos disease. Although Cowden disease is little known, making the diagnosis is very important, because cancer frequently occurs in the patients famility and genetic counseling is necessary.


Neurosurgery | 1986

Trigeminal neurinoma associated with suprasellar arachnoid cyst: case report

Masaharu Amagasa; Hiroo Sato; Hiroshi Niizuma; Jiro Suzuki

The first case of trigeminal neurinoma associated with suprasellar arachnoid cyst is presented. Coexistence of these two lesions may be accidental, but it is also possible that the arachnoid cyst was secondary to the neurinoma.


The Lancet | 2001

Ruptured intracerebral abscess

Yasuhiko Matsumori; Masaharu Amagasa; So Sato

25 Fisher LD, Kennedy JW, Davis KB, et al. Association of sex, physical size, and operative mortality after coronary artery bypass in the Coronary Artery Surgery Study (CASS). J Thorac Cardiovasc Surg 1982; 84: 334–41. 26 Berkman LF, Leo-Summers L, Horwitz RI. Emotional support and survival after myocardial infarction. A prospective, population-based study of the elderly. Ann Intern Med 1992; 117: 1003–09. 27 Case RB, Moss AJ, Case N, McDermott M, Eberly S. Living alone after myocardial infarction: impact on prognosis. JAMA 1992; 267: 515–19. 28 Frasure-Smith N, Lesperance F, Gravel G, et al. Social support, depression, and mortality during the first year after myocardial infarction. Circulation 2000; 101: 1919–24. 29 Schleifer SJ, Macari-Hinson MM, Coyle DA, et al. The nature and course of depression following myocardial infarction. Arch Intern Med 1989; 149: 1785–89. 30 Langeluddecke P, Fulcher G, Baird D, Hughes C, Tennant C. A prospective evaluation of the pyschosocial effects of coronary artery bypass surgery. J Psychosom Res 1989; 33: 37–45 ARTICLES


Brain Tumor Pathology | 2000

Pilocytic astrocytoma arising from an area of nudular heterotopia located in the white matter of the temporal lobe: case report

Masaharu Amagasa; Hideaki Kojima; Fumiaki Yuda; Satoru Ohtomo; Yoshihiro Numagami; So Sato

A 16-year-old girl suffering from intractable temporal lobe epilepsy presented with a pilocytic astrocytoma, which occurred in an area of nodular heterotopia located in the white matter of the temporal lobe. The pilocytic astrocytoma appeared to be covered by an area of gliosis, which contained numerous Rosenthal fibers, while in the lesion the pilocytic astrocytoma occupied a small area. The gliosis eventually became a tumor-like lesion. The while matter around the mass was composed of gliosis with nodular heterotopia. Temporal developmental malformation, which was a basic lesion of the patient, might therefore be a precursor lesion of pilocytic astrocytomas.


Surgical Neurology | 1996

Spinal malignant lymphoma appearing after radiation and chemotherapy of a pineal region tumor

Masaharu Amagasa; Makoto Kawase; So Sato; Fumiaki Yuda

The occurrence of malignant lymphoma in the pineal region is very rare. We experienced a case of pineal region tumor that was treated by radiation and chemotherapy. After 1 year, the tumor metastasized to the cauda equina and was operated on. The diagnosis was malignant lymphoma. Although the incidence of intracranial malignant lymphoma is known to be on the increase recently, malignant lymphoma should be considered in the differential diagnosis of pineal region tumors.


Brain Research | 1990

Effects of calcium and calcium antagonists against deprivation of glucose and oxygen in guinea pig hippocampal slices

Masaharu Amagasa; Akira Ogawa; Takashi Yoshimoto


Journal of Neurosurgery | 1986

Early cerebral angiography after aneurysm rupture. Analysis of 197 cases.

Masaharu Amagasa; Takashi Yoshimoto; Kazuo Mizoi; Jiro Suzuki


Surgery for Cerebral Stroke | 1987

Surgical Treatment of Intracranial Traumatic Aneurysm

Masaharu Amagasa; Takehide Onuma; Jiro Suzuki

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Akira Ogawa

Iwate Medical University

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