| Project/Area Number |
10671317
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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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 | KITASATO UNIVERSITY |
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Principal Investigator |
IRIKURA Katsumi Kitasato Univ.Sch.of Medicine, Assistant Prof., 医学部, 講師 (70176519)
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| Co-Investigator(Kenkyū-buntansha) |
FUJII Kiyotaka Kitasato Univ.Sch.of Medicine, Professor, 医学部, 教授 (10128085)
YOSHIO Miyasaka Kitasato Univ.Sch.of Medicine, Associate Prof., 医学部, 助教授 (90104538)
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 2000: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1999: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1998: ¥900,000 (Direct Cost: ¥900,000)
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| Keywords | hypothermia / acid-base management / autoregulation / cerebral blood flow / cerebral ischemia / cranial window / rat / rat / hypothermia / cerebral blood flow / acid-base managemeut / autoregulation |
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| Research Abstract |
We studied changes in reactivity of the pial arterioles, cerebral blood flow (CBF), and cerebral oxygen metabolism under hypothermia in Sprague-Dawley rats. Hypothermia of 30℃ was introduced after stable baseline condition and the influence of acid-base management during hypothermia was examined. The cerebrovascular response to induced hypotension and hypercapnia was studied using a closed cranial window technique, which allowed us to observe the pial arterioles in situ and measure diameter of the vessels continuously. Moderate hypothermia attenuated dilation of the pial arterioles to hypotension. In contrast, hypercapnic vasodilation was preserved. Cerebral blood flow measured by hydrogen clearance method in the caudoputamen and laser-Dappler flowmetry in the cortex decreased 40-50% of the baseline in alpha-stat management, whereas changes in cerebral blood flow were not significant in pH-stat management. The cerebral metabolic rate for oxygen by multiplying cerebral blood flow (sagit
… More
tal sinus hydrogen clearance) by the cerebral arteriovenous difference in oxygen contents was reduced in both alpha-stat and pH-stat managements during mild to moderate hypothermia. Therefore it was suggested that uncoupling of cerebral blood flow and metabolism might occur in pH-stat management. We also studied the influence of acid-base management on the ischemic penumbra CBF and infarction volume in the rat transient middle cerebral artery occlusion (MCA-O) model in spontaneously hypertensive rats. First, we introduced moderate hypothermia before ischemia and observed the greater reduction in CBF of the penumbra area in the hypothermic alpha-stat group. However, the penumbra CBF decreased in association with MCA-O to the same level in these acid-base managements. No significant difference was observed in infarction volume. Second, we introduced hypothermia during MCA-O.The penumbra CBF in both two acid-base managements showed reduction in the same degree and no significant difference in infarct volume was observed. Our results indicated that acid-base management did not affect on the penumbra CBF and infarct volume if hypothermia was induced before or during ischemia. The effect of acid-base management induced during reperfusion phase remains to be clarified. Less
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