| Project/Area Number |
08044287
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Joint Research |
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| Research Institution | Tottori University |
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Principal Investigator |
KAWAI Yasuaki Tottori University, Faculty of Medicine, Professor, 医学部, 教授 (70143972)
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| Co-Investigator(Kenkyū-buntansha) |
MURTHY Gita University of California at San Diego, Researcher, サンディエゴ校, 共同研究員
HARGENS Alan R NASA Ames Research Center, Researcher, Ames研究所, 主任研究員
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| Project Period (FY) |
1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1996: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | Microgravity / Cerebral Blood Flow / Intracranial Pressure / Ocular Blood Flow / Intraocular Pressure / Heed-Down Tilt / Laser Doppler / Near Infrared / ヘッドダウンテイルト |
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| Research Abstract |
As the result of recent development in aerospace technology, human subjects have been exposed to an extreme environment such as microgravity when they go up to the space. Therefore, it is important to investigate the influence of microgravity on human physiological functions. Thus in the prresent study, effects of simulated microgravity on cerebral hemodynamics and the counter measures were studied in humans and experimental animals.
(1) Development of New Method for ICP (Intracranial Pressure) Measurement : Since 1994, Dr.Hargens at NASA Ames and Kawai have collaborated to develop a new non-invasive technique for measurement of ICP using ultrasound. In the present study, the ultrasound technique documented a linear relationship between intracranial distance and ICP in two cadavera, suggesting a possibility to apply this technique to quantify ICP in humans. (2) Brain Oxygenation and Hemoglobin Concentration during Postural Change : Human study using near infrared spectroscopy demonstrated that postural change from upright standing to horizontal supine increased brain oxygenation by 9.4% and hemoglobin concentration by 4.9%, suggesting a transient increase in cerebral blood flow. (3) Intracranial Pressure and Cerebral Blood Flow during Head-down Tilt (HDT) : Intracranial pressure elevated by 2 mmHg in rast and by 12 mmHg in rabbits right after exposure to HDT (negative 45 degree). Cerebral blood flow did not show a significant change during 2 hour HDT in rabbits. (4) Intraocular Pressure and Ocular Blood Flow during HDT in Rabbits : Exposure to HDT increased intraocular pressure by 2 mmHg and ocular blood flow by 10% above the baseline. Animal model for cerebral hemodynamics during microgravity has not been established. Further studies are recommended to investigate time course of such parameters during prolonged exposure to microgravity.
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