著者

渡辺 俊明 田中 正彦 渡邉 和俊 高松 康雄 戸部 昭広

出版者

公益社団法人 日本薬学会

雑誌

YAKUGAKU ZASSHI (ISSN:00316903)

巻号頁・発行日

vol.124, no.3, pp.99-111, 2004-03-01 (Released:2004-02-25)

参考文献数

51

被引用文献数

84 86

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Increasing data suggest that oxygen free radical species play detrimental roles in ischemic diseases. A free radical scavenger capable of inhibiting oxidative injury is expected to become a new drug for the treatment of ischemic diseases such as cerebral ischemia. Edaravon (3-methyl-1-phenyl-2-pyrazolin-5-one), which has been developed as an neuroprotective agent for more than 15 years since its discovery, is approved for the treatment of acute cerebral infarction. In this paper, the pharmacologic characteristics and clinical effects of edaravone are reviewed. In early stage of investigation, edaravone was found to have promising activities as an antioxidative radical scavenger, quenching hydroxyl radical (•OH) and inhibiting both •OH-dependent and •OH-independent lipid peroxidation. Edaravone showed inhibitory effects on both water-soluble and lipid-soluble peroxyl radical-induced peroxidation systems, which are different from the inhibitory effects of vitamins C and E in each system, respectively. Oxidative injury to cultured endothelial cells caused by arachidonate (AA) peroxides is prevented in the existence of edaravone. To clarify the characteristics of this free radical scavenger, further investigation was carried out. Edaravone ameliorated exacerbation of cortical edema induced by a focal ischemia-reperfusion model in rats, suggesting inhibitory effects on oxidative injury to the blood-brain barrier (BBB). Additionally, edaravone also prevented rat cortical edema caused by intracortical AA infusion in which free radical production and subsequent oxidative injury to the BBB are involved. With advances in in vivo measurement technology of oxygen radicals, edaravone was shown to inhibit postischemic increases in •OH production and tissue injury in the penumbral or recirculated area in rat cerebral ischemia models. In clinical studies, edaravone improved the core neurologic deficits, activities of daily living, and functional outcome of stroke patients. Furthermore, a study using proton magnetic resonance spectroscopic techniques showed that edaravone preserved N-acetyl-aspartate in stroke patients, a promising neuronal marker in the brain. Further investigation is essential for a better understanding of free radical-mediated cerebral injury during ischemia followed by recirculation. We hope that edaravone represents a promising neuroprotectant for drug therapy in acute cerebral ischemia.

著者

鎌田 照章 松本 清則 谷口 和哉 渡邉 和俊 飯田 和也 大谷 靖郎 石橋 大輔

出版者

公益社団法人 土木学会

雑誌

海岸工学論文集 (ISSN:09167897)

巻号頁・発行日

vol.47, pp.696-700, 2000-10-20 (Released:2010-03-17)

参考文献数

6

被引用文献数

1 1

著者

小菅 正裕 渡邉 和俊 橋本 一勲 葛西 宏生

出版者

公益社団法人 日本地震学会

雑誌

地震 第2輯 (ISSN:00371114)

巻号頁・発行日

vol.65, no.1, pp.69-83, 2012-09-28 (Released:2012-10-26)

参考文献数

33

被引用文献数

1 5

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We have investigated the inland seismic activity induced by the 2011 Off the Pacific coast of Tohoku (Tohoku-oki) Earthquake in the northern part of Tohoku district, using JMA catalog and newly determined focal mechanism solutions. The seismicity is quite high in the Akita prefecture, forming newly activated clusters. The cluster locations are complementary for the periods before and after the Tohoku-oki Earthquake. A stress tensor inversion using focal mechanism data indicates that the stress field has changed from reverse-faulting regime to strike-slip regime, with a counter-clockwise rotation of the maximum principal stress axis and the replacement of the other two principal axes. This change is qualitatively explained by the weakened E-W compressional stress due to megathrust faulting of the Tohoku-oki Earthquake. Thus the new stress field in the investigated area is unfavorable to the preexisting fault planes of reverse faulting, which brought the complementary seismic activity. Among the three active clusters in the Akita prefecture, the one to the north of Moriyoshi volcano is interesting, because the swarm-like activity forms a volumetric source with a dimension of about 3 km. Considering a possible existence of crustal fluid suggested by a reflected phase, delayed beginning of seismic activity about 2 month from the Tohoku-oki Earthquake, and the migration of seismic activity, the induced seismic activity in the area may be related to a response of crustal fluid to the coseismic stress change. Detailed investigation of the result of stress tensor inversion reveals the existence of local stress field superposed on the regional field represented by the average stress tensor. Inferred local stress field exists in the Tsugaru Strait area, southern part of Akita prefecture, and Kitakami Mountains.