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Dive into the research topics where Osamu Tone is active.

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Featured researches published by Osamu Tone.


Acta neurochirurgica | 2003

Chronological changes of perihematomal edema of human intracerebral hematoma

Motoki Inaji; Hiroki Tomita; Osamu Tone; M. Tamaki; Ryuta Suzuki; K. Ohno

Recent investigations have indicated the importance of secondary brain damage in the pathophysiology of intracerebral hemorrhage (ICH), which includes ischemic brain damage and edema formation around a hematoma. The purpose of the current study is to investigate chronological changes of perihematomal edema in patients with human ICH and also the correlation between volume of perihematomal edema and neurological status. Fourteen patients with medium-sized putaminal hemorrhage (29.4 +/- 13.2 ml) without hematoma enlargement were included in this study. To investigate chronological changes of perihematomal edema, we performed CT scans prospectively on the day of hemorrhage and repeated them on days 1, 3, 7, 14, and 28. We evaluated the patients neurologically using the NIH stroke scale on the day a CT scan was performed. The volume of perihematomal edema in human ICH increased rapidly three days after hemorrhage and the score on the NIH stroke scale showed a deterioration. The volume of perihematomal edema then increased slowly until day 14 after hemorrhage, and decreased thereafter. Despite progression of perihematomal edema, the score on the NIH stroke scale improved gradually after day 3.


Surgical Neurology | 1989

Changes in cerebral hemodynamics following encephalo-duro-arterio-synangiosis (EDAS) in young patients with moyamoya disease☆

Ryuta Suzuki; Yoshiharu Matsushima; Yoshiaki Takada; Tadashi Nariai; Shinichi Wakabayashi; Osamu Tone

To evaluate the effect of encephalo-duro-arterio-synangiosis, (EDAS), we obtained follow-up angiograms and measured regional cerebral blood flow in 21 young patients with Moyamoya disease. Carotid fork stenosis continued to progress after EDAS, although angiography demonstrated a marked increase in the number of middle cerebral artery branches via implanted arteries. Preoperative cortical blood flow was lower than normal. The post-EDAS increases in hemispheric and cortical flow were significant in patients with transient ischemic attacks, but not in patients with infarction. The increase in cortical flow at the site of EDAS was first noted 2 weeks after EDAS.


Acta neurochirurgica | 1994

High Colloid Oncotic Therapy for Contusional Brain Edema

Hiroki Tomita; Umeo Ito; Osamu Tone; H. Masaoka; B. Tominaga

We investigated whether prolonged high colloid oncotic therapy for two weeks can suppress contusional brain edema. Eighteen patients with cerebral contusion were randomly divided into two groups of patients receiving high oncotic pressure (HOP; 26-30 mmHg) treatment and those receiving normal oncotic pressure (NOP; 22-26 mmHg) treatment. Oncotic pressure was maintained for two weeks with administration of a 25% albumin solution with additional use of furosemide. Edema volume was calculated by summation of all measured low-density areas in each CT slice multiplied by 1.0 cm of slice of thickness. We expressed contusional brain edema volume as a percent increase based on each patients initial CT. The mean percent increase of contusional brain edema in the NOP group was significantly higher than that in the HOP group at 9-15 days (208.9% and 14.0%, respectively) and 16-25 days (188.8% and 10.0%, respectively). There were no complications such as heart failure or renal failure during treatment. All the patients in the HOP group recovered with minimal or no neurological deficit. On the other hand, 30% of patients in the NOP group remained in poor condition. With frequent measurement of oncotic pressure and adjustment of fluids and electrolytes, continuous oncotic therapy for two weeks effectively and safely reduced contusional brain edema.


Journal of the Neurological Sciences | 1998

A clinical, genetic, neuropathological study in a Japanese family with SCA 6 and a review of Japanese autopsy cases of autosomal dominant cortical cerebellar atrophy

Kuniaki Tsuchiya; Kinya Ishikawa; Sadakiyo Watabiki; Osamu Tone; Kazuhiro Taki; Chie Haga; Minoru Takashima; Umeo Ito; Riki Okeda; Hidehiro Mizusawa; Kenji Ikeda

This report concerns a Japanese family with genetically confirmed SCA 6, including an autopsy case, and a review of Japanese autopsy cases of autosomal dominant cortical cerebellar atrophy (ADCCA). The proband (Case 1) was a Japanese woman. She developed gait disturbance at age 62. The father and younger sister (Case 2) had the same disorder. She died at age 67 due to subarachnoid hemorrhage. Neuropathological examination revealed severe loss of Purkinje cells in the cerebellum, prominently in the dorsal vermis, and absence of neuronal loss in the inferior olives. Molecular genetic study showed the CAG-repeat expansion of SCA 6 gene. The younger sister (Case 2) developed gait disturbance at age 62. Neurological examination at age 66 revealed cerebellar signs without sensory disturbance. Neuroimaging at this time showed cerebellar atrophy, prominently in the vermis. She died of multiple myeloma at age 66. A neuropathological review of Japanese autopsy cases of ADCCA showed that there are two patterns in the distribution of cerebellar cortical lesions of Japanese patients with ADCCA. The distribution of cerebellar cortical lesions in genetically confirmed Japanese patients with SCA 6 is more prominent in the vermis than in the hemisphere.


Acta neurochirurgica | 1994

Peritumoral Edema in Meningioma: a Contrast Enhanced CT Study

Umeo Ito; Hiroki Tomita; Osamu Tone; H. Masaoka; B. Tominaga

The propagation of extravasated contrast medium around 6 supratentorial meningiomas with peritumoral white matter of low density (PWL) of Lanksch II-III was investigated by repeated CT scanning at 4 h intervals, following a 1 h drip infusion of 200 ml of Iopamidol. The volume of the expanding peritumoral contrast enhancement was calculated according to a method previously described. By calculating the increase in volume from the first to the second scan, and from the second to third, we derived the rate of edema formation as well as the resolution rate of edema in the PWL. The surface area of the entire tumor (TS) and area of tumor surface facing the PWL (LS) were calculated by summating the surface areas of all CT slices, each area of which was derived from the measured length of the entire circumference of the tumor and circumference of the tumor facing the PWL, respectively, multiplied by the slice thickness of 0.5 cm. The volume of PWL, edema formation rate of entire tumor, and tumor volume x LS/TS were well correlated with each other. We concluded that the severity of peritumoral edema in meningiomas depends on the size of the tumor and the extent of tumor surface contact with the PWL.


Acta Neurologica Scandinavica | 1996

Correlation between cerebral blood flow values obtained by Xenon/CT and Kety‐Schmidt (N2O) methods

Osamu Tone; Umeo Ito; Hiroki Tomita; Hideaki Aklmoto; Hlsaakl Sakeml

The means of the cerebral blood flow (CBF) values obtained by the stable xenon enhanced CT (Xe/CT) method using two different CT scanners were compared with the global CBF value obtained by the Kety‐Schmidt (N2O) method as a reference. Xe/CT CBF values were obtained using a GE CT9200 (31 patients, 2 flow maps, 120 kV, absorption constant of 0.040) as well as a GE ProSeed Accell (38 patients, 4 flow maps, 80 kV, absorption constant of 0.028). The protocol of inhalation in the Xe/XT method consisted of 4 min wash‐in and 4‐min wash‐out of 35% stable xenon. In the Kety‐Schmidt method, 15% N2O gas was inhaled for 10 min. The N2O content of blood samples was measured using a van Slyke‐Neill blood gas analyzer. We corrected all obtained CBF values for a PaCO2 of 34 mmHg (CBF34).


Surgical Neurology | 1994

Atrophy and maldevelopment of the ipsilateral cerebral hemisphere after acute subdural hematoma in infants

Hiroki Tomita; Umeo Ito; Osamu Tone; Hiroyuki Masaoka; Ben Tominaga

Among nine infants aged less than 4 years with acute subdural hematoma admitted between 1980 and 1991, five required evacuation of a hematoma. Eight of them survived longer than 1 month and the remaining patient who had a hematoma removal died 3 days postoperatively. The four infants who required evacuation of a hematoma and survived longer than 1 month had prolonged hemispheric swelling ipsilateral to the hematoma lasting for 2 weeks postoperatively. Intracranial pressure was higher than 25 mm Hg during this period. Diffuse high density was observed in the affected hemisphere in one patient 12 days after injury, which was assumed to be hemorrhagic infarction. Subsequently, these four infants developed atrophy of the cerebral hemisphere ipsilateral to the hematoma. The pathophysiology of the atrophy of the cerebral hemisphere ipsilateral to the acute subdural hematoma is discussed.


Neurologia Medico-chirurgica | 2017

Correlations between Cognitive Impairments and Employment Status in Patients with Diffuse Axonal Injury.

Shin Hirota; Motoki Inaji; Tadashi Nariai; Mutsuya Hara; Masashi Tamaki; Taketoshi Maehara; Hiroki Tomita; Osamu Tone

Patients with diffuse axonal injury (DAI) may initially present with prominent physical impairments, but their cognitive dysfunctions are more persistent and are attributable to later unemployment. In this study, we analyzed how the findings of early and delayed neuropsychological assessments correlated with employment outcome of patients with DAI. A total of 56 patients with DAI without motor or visual dysfunction were included in this study. The neuropsychological battery consisted of the Wechsler Adult Intelligent Scale - Revised (WAIS-R), Wechsler Memory Scale - Revised (WMS-R), Trail Making Test (TMT), Wisconsin Card Sorting Test (WCST), and Word Fluency Test (WFT). This battery of tests was administered twice in early stage after injury and in later stage. The results of all of the neuropsychological tests improved significantly (P <0.001) between the early and later assessments. All scores other than TMT part A and B improved to the normal range (Z-score ≥ 2). The patient characteristics (age, gender, initial Glasgow Coma Scale, and duration of posttraumatic amnesia) had no relationship to the outcome. The results of TMT part B, however, were significantly correlated with employment outcome in both the early and later assessments (P = 0.01, 0.04). Given that TMT evaluates visual attention, we surmise that a lack of attention may be the core symptom of the cognitive deficit and cause the re-employment failure in patients with DAI. TMT part B in both early and later assessments has the potential to accurately predict chronic functional outcome.


Journal of Clinical Neuroscience | 2010

Efficacy of the American Heart Association/American Stroke Association guidelines for ultra-early, intentional antihypertensive therapy in intracerebral hemorrhage

Mutsumi Fujii; Kazuhiko Nakagawa; Hiroki Tomita; Osamu Tone; Masashi Tamaki; Yoshiaki Takada; Mitsuhiko Hokari; Tadashi Nariai; Kikuo Ohno

Whether the intentional antihypertensive therapy recommended by the American Heart Association/American Stroke Association (AHA/ASA) guidelines has clinical benefit for patients who have acute spontaneous intracerebral hemorrhage (ICH) has yet to be proven. We retrospectively reviewed the clinical charts of 175 patients with putaminal or thalamic ICH with acute hypertension to examine the correlation between the efficacy of antihypertensive therapy within 3 hours of onset, hematoma expansion (HE) after hospitalization and clinical outcome. The aim of the antihypertensive therapy was to achieve and maintain a systolic blood pressure of 120 mm Hg to 160 mm Hg until the second CT scan. The mean arterial pressure (MAP) after admission was the average MAP values measured every hour for the first 3 hours of hospitalization or until the second CT scan, if this was performed within the same timeframe. Thirty-two (18.3%) patients were found to have HE. Prior to the second CT scan, antihypertensive medications were administered to all patients without any major complications. A multiple logistic regression analysis revealed that a MAP of >110 mm Hg after admission was the only variable independently associated with HE (odds ratio [OR] = 3.455; 95% confidence interval [CI] = 1.510-8.412; p = 0.004). Modified Rankin Scale scores of < or = 3 on day 30 were significantly more common in those patients without HE (p = 0.002). Our findings suggest that there are clinical benefits, by the prevention of subsequent HE, in maintaining a MAP level lower than that recommended by the AHA/ASA (110 mm Hg) after hospitalization for patients who have ICH.


神経外傷 | 2004

Neuropsychological recovery in pediatric patients with acute subdural hematoma treated with mild hypothermia therapy : Report of two cases

Shoji Yokobori; Hiroki Tomita; Osamu Tone; Masashi Tamaki; Youhei Sato; Motoaki Nakabayashi; Shinji Inada; Atsushi Katsumi; Shinichirou Suzaki; Tomoko Yamazaki; Hiroyuki Yokota; Yasuhiro Yamamoto

In Case 1, an 11-year-old boy fell and struck the occipital part of his head. He was admitted to our hospital with a Glasgow Coma Score (GCS) of 4, and both pupils were dilated. Computed tomography (CT) showed a right acute subdural hematoma (ASDH), necessitating an emergency decompressive craniectomy and hematoma removal. In Case 2, a 6-yearold girl was admitted with severe head injuries caused by a traffic accident. Her GCS was 5 (El VI M3) and both pupils were dilated. Emergency CT showed a left ASDH and acute brain swelling, necessitating a decompressive craniectomy and hematoma removal. These two children were both treated with mild hypothermia after the evacuation of ASDH. Neuropsychological examinations were conducted 6 months and 1 year after injury. The Wechsler Intelligence Scale for Children, third edition (WISC-III), and the social maturity scale were used to score their total intellects and social behaviors. The results showed that mild hypothermia could be a beneficial therapy in preserving neuropsychological function in pediatric patients suffering from severe head injuries.

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Hiroki Tomita

Tokyo Medical and Dental University

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Masashi Tamaki

Tokyo Medical and Dental University

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Mutsuya Hara

Tokyo Medical and Dental University

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Motoki Inaji

Tokyo Medical and Dental University

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Tadashi Nariai

Tokyo Medical and Dental University

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Mutsumi Fujii

Tokyo Medical and Dental University

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