| Project/Area Number |
16390407
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Cerebral neurosurgery
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| Research Institution | Hamamatsu University School of Medicine |
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Principal Investigator |
YAMAMOTO Seiji Photon Med Res Ctr, Associate Professor, 光量子医学研究センター, 助教授 (60144094)
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| Co-Investigator(Kenkyū-buntansha) |
TERAKAWA Susumu Photon Med Res Ctr, Professor, 光量子医学研究センター, 教授 (50014246)
SAKURAI Takashi Photon Med Res Ctr, Research Associate, 光量子医学研究センター, 助手 (50283362)
TSUKADA Hideo Central Research Laboratory, Hamamatsu Photonics, Chief Researcher, 中央研究所, 主任部員 (10393951)
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| Project Period (FY) |
2004 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥12,900,000 (Direct Cost: ¥12,900,000)
Fiscal Year 2006: ¥4,500,000 (Direct Cost: ¥4,500,000)
Fiscal Year 2005: ¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 2004: ¥4,600,000 (Direct Cost: ¥4,600,000)
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| Keywords | Intravital Cell Imaging / Confocal Laser Microscope / Cerebral Ischemia / Photodynamic Therapy / Free Radical / Reactive Oxygen Species / 蛍光蛋白 / 蛍光色素 / イメージングファイバー / グリオーマ |
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| Research Abstract |
Mounting evidences indicate that the calcium ion and reactive oxygen species (ROS) play key roles in many diseases of the brain. Most of them have been studied using cultured cells. However, in whole animals, calcium response and the production of ROS following ischemia remains to be established, since no method has been available to measure the [Ca^<2+>]_i and ROS in the brain of living animals. In the present study, we sought to determine, in rats, 1) the production of ROS following brain ischemia ; and 2) the [Ca^<2+>]_i changes following transient forebrain ischemia in hippocampus. In addition, 3) during photodynamic therapy (PDT), we sought to monitor the production of singlet oxygen (^1O_2), one of the ROS, in rat glioma. The results in the present project must be useful to examine the cellular mechanism in situ, and thereby valuable to develop the methods for the treatment of the brain disease including cerebral infarction and brain tumor.
1) We established a new semi-quantitativ
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e analysis system that can spatiotemporally detect the cortical intracellular production of ROS. Ischemia/reperfusion-dependent production of superoxide radical (・O_2^-) and hydroxyl radical (・OH) were measured by intravital imaging using fluorescence dye. The result indicated that ・O_2^- and・OH production increased in the early period of reperfusion but not during the ischemia.
2) To determine, in rats, the [Ca^<2+>]_i changes following transient forebrain ischemia in hippocampus, we employed a fiber-coupled confocal microscope to observe the confocal images in hippocampus. In CA1, but not in CA3, transient forebrain ischemia induced long lasting [Ca^<2+>]i increase in situ. Since the [Ca^<2+>]_i increase was significantly larger in CA1 during reperfusion period, it might reach to toxic levels and then mediate the vulnerability of CA1 against ischemia.
3) Using a new near infrared-photomultiplier tube system, we monitored the real-time production of ^1O_2 during PDT and investigated the relationship between the ^1O_2 production and photodynamic effects. Our results indicated that the optimal condition of irradiation should be decided based on the ^1O_2 generation. Less
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