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Featured researches published by Youichi Itoyama.


Neurosurgery | 1990

Clinical study of intracranial nongerminomatous germ cell tumors producing alpha-fetoprotein

Youichi Itoyama; Masato Kochi; Haruaki Yamamoto; Jun Ichi Kuratsu; Shozaburou Uemura; Yukitaka Ushio

We present six patients with intracranial nongerminomatous germ cell tumors that produced alpha-fetoprotein (AFP). Their ages ranged from 8 to 20 years (average, 11.5 years old); two were male and four were female. Four of the tumors originated in the pineal region and two in the suprachiasmatic region. One patient treated with only radiation therapy died within 3 months of admission as a result of intraperitoneal metastasis via a ventriculoperitoneal shunt. Another patient, treated with radiation therapy and intrathecal administration of neocarzinostatin, died after 12 months because of tumor progression and subarachnoid dissemination. Two patients who received radiation and combination therapy with cisplatin, vinblastine, and bleomycin died after 13 and 25 months. The remaining two patients treated with radiation therapy and adjuvant chemotherapy (cisplatin and etoposide) are now alive without recurrence after 16 and 19 months from admission. Adjuvant chemotherapy with cisplatin and etoposide appears to be efficacious in the treatment of intracranial nongerminomatous germ cell tumor.


Neurosurgery | 1994

Significance of Elevated Thrombin-Antithrombin III Complex and Plasmin-α2-Plasmin Inhibitor Complex in the Acute Stage of Nontraumatic Subarachnoid Hemorrhage

Youichi Itoyama; Shodo Fujioka; Shuichi Takaki; Motohiro Morioka; Takuichiro Hide; Yukitaka Ushio

Thrombin-antithrombin III complex (TAT) and plasmin-alpha 2-plasmin inhibitor complex (PIC) were examined in the acute stage in 51 patients with nontraumatic subarachnoid hemorrhage. TAT and PIC values were correlated with severity at the time of onset and with outcome. In the patients whose TAT levels were 25 ng/ml or more and PIC levels were 3.0 micrograms/ml or more (n = 16), only 25% had a good or fair outcome. In the patients with TAT levels less than 25 ng/ml or PIC levels less than 3.0 micrograms/ml (n = 35), on the other hand, 82.9% had a good or fair outcome. There were no significant differences in TAT and PIC levels between patients who experienced arterial spasm and those who did not. These results indicate that TAT and PIC values may reflect the severity of the brain damage induced by subarachnoid hemorrhage. It is speculated that marked coagulation and fibrinolytic disorders occur in the acute stage of subarachnoid hemorrhage.


Neurosurgery | 1997

Ruptured distal accessory anterior cerebral artery aneurysm: case report.

Motohiro Morioka; Shodo Fujioka; Youichi Itoyama; Yukitaka Ushio

OBJECTIVE AND IMPORTANCE Accessory anterior cerebral artery (ACA), which is a type of median artery of anomalous triplicate ACA, is not rare, but aneurysmal formation is extremely rare. We report a rare case with ruptured aneurysm arising from a distal accessory ACA. We discuss the characteristics and causes of this type of aneurysm and classification of this anomaly. CLINICAL PRESENTATION A 63-year-old man suddenly developed severe headache and then loss of consciousness and paraplegia. Computed tomography disclosed thick and diffuse subarachnoid hemorrhage and interhemispheric hematoma. Subsequent bleeding occurred 2 hours after the first hemorrhage. Cerebral angiography disclosed a saccular aneurysm arising from the distal accessory ACA. INTERVENTION Neck clipping of the aneurysm was performed 22 hours after the second episode, using an interhemispheric approach. CONCLUSION Although transient paraplegia occurred 8 days after onset, the patient recovered well after surgery without neurological deficit. The characteristics of the aneurysm arising from distal accessory ACA are considered similar to those of distal ACA aneurysm. There is, however, some confusion regarding the terminology of the anterior communicating artery complex anomalies, which we discuss.


Neurosurgery | 1990

Brain metastasis from malignant fibrous histiocytoma of the heart: Case report

Youichi Itoyama; Shinji Nagahiro; Hiroshi Seto; Nobuyuki Sueyoshi; Jun Ichi Kuratsu; Yukitaka Ushio

This is the second reported case of a malignant fibrous histiocytoma of the heart that metastasized to the brain. A 33-year-old woman developed headache, nausea, and ataxic gait 9 months after removal of the tumor from the left atrium of the heart. Computed tomographic and magnetic resonance imaging scans disclosed multiple metastatic tumors in the brain. Although dramatic improvement in her symptoms and signs followed the removal of the brain tumors, she died of tumor recurrence in the left atrium 3 months after the removal of the metastatic brain tumors.


Journal of Neurosurgery | 1989

Natural course of unoperated intracranial arteriovenous malformations: study of 50 cases

Youichi Itoyama; Syouzaburou Uemura; Yukitaka Ushio; Jun Ichi Kuratsu; Nobuhito Nonaka; Hidetaka Wada; Yoshinori Sano; Akinobu Fukumura; Kensei Yoshida; Tatsushi Yano


Journal of Neurosurgery | 2003

Successful treatment of intracranial nongerminomatous malignant germ cell tumors by administering neoadjuvant chemotherapy and radiotherapy before excision of residual tumors

Masato Kochi; Youichi Itoyama; Shoji Shiraishi; Isao Kitamura; Toru Marubayashi; Yukitaka Ushio


Journal of Neurosurgery | 1999

Preliminary observations for a new treatment in children with primary intracranial yolk sac tumor or embryonal carcinoma : Report of five cases

Yukitaka Ushio; Masato Kochi; Jun Ichi Kuratsu; Youichi Itoyama; Toru Marubayashi


Neurosurgery | 1995

Treatment of intracranial nongerminomatous malignant germ cell tumors producing α-fetoprotein

Youichi Itoyama; Masato Kochi; Jun Ichi Kuratsu; Seishi Takamura; Ikuo Kitano; Toru Marubayashi; Shozaburo Uemura; Yukitaka Ushio


Neurologia Medico-chirurgica | 1990

Intracranial Arterial Vasospasm Associated with Pituitary Apoplexy after Head Trauma : Case Report

Youichi Itoyama; Satoshi Goto; Masatake Miura; Jun Ichi Kuratsu; Yukitaka Ushio; Takashi Matsumoto


Journal of Neurosurgery | 1995

Kernohan's notch in chronic subdural hematoma: findings on magnetic resonance imaging

Youichi Itoyama; Shodo Fujioka; Yukitaka Ushio

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