| Project/Area Number |
06671432
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Cerebral neurosurgery
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| Research Institution | National Cardiovasular Center Reseauch Institute |
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Principal Investigator |
SEKI Junji Natl.Cardiovasc Ctr Res Inst.Dept Biomed Eng, Research Fellow, 生体工学部, 室長 (20163082)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAMIZAWA Keiichi Natl.Cardiovasc Ctr Res Inst.Dept Biomed Eng, Research Fellow, 生体工学部, 室員 (10163312)
MATSUDA Takehisa Natl.Cardiovasc Ctr Res Inst.Dept Biomed Eng, Head of Dept, 生体工学部, 部長 (60142189)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1995: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1994: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | Brain Pial Microvessels / Laser-Doppler Anemometer / Pulsatile Flow / Amplitude of Pulsation / Wave Propagation / Propagation Velocity / Vessel Wall Elasticity / Intracranial Pressure / 血流脈波 |
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| Research Abstract |
This research project was aimed to establish the applicability of our developed fiber-optic laser-Doppler anemometer microscope (FLDAM) to the measurement of red cell velocity in the cerebral pial microvessels and was also aimed to analyze the blood flow dynamics under the increased intracranial pressures.
A closed cranial window was implanted on one side of the parietal region of rats to observe the brain pial microcirculation. The red cell velocity in single pial microvessels with diameter range from 10 to 230 mum was successfully measured by the FLDAM.The red cell velocity in arterioles showed regular pulsation synchronous with the heart beats with amplitude up to 46 % of the mean velocity, while the velocity in venules only showed random fluctuations with small amplitude. The amplitude of velocity pulsation was defined as the half of the difference betweenthe maximum and minimum of the ensemble average velocity. The temporal mean velocity in the arterioles increased with increasing
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diameter. It was 3.5 and 14 mm/s for the arteriole with 10 and 50 mum in diameter, respectively, on an average. The time lag of the velocity in the arteriole relative to the femoral arterial pressure increased with the distance along the vessel from upstream to downstream, which indicates the propagation of flow pulse along the arteriole. The propagation velocity of flow pulse was determined for several pial arterioles. It ranged between 10 and 115 cm/s.
Effects of intracranial pressure (ICP) on the pial microcirculation were studied by changing the internal pressure of the closed cranial window implanted in the rats. The average diameter of venules decreased monotonically from 1.1 to 0.78 as the ICP increased from 0 to 50 mmHg, where the diameter is normalized by the diameter at ICP=5mmHg. On the other hand, the temporal mean velocity in venules increased monotonically from 0.85 to 1.91. As a result, the volume flow rate in venules did not change significantly with ICP.The changes of arterioles with ICP were small compared with those of venules. The amplitude of velocity pulsation in arterioles showed stepwise increase with ICP at a certain value of ICP,ICP_<cr'> which depended on the location of the vessel. ICP_<cr> increased with increasing vessel diameter and decreased from upstream to downstream along an arteriole, suggesting that ICP_<cr> represents the intravascular pressure of the arteriole at a certain phase of pulsation. Less
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