| Project/Area Number |
04670461
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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 |
呼吸器内科学
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| Research Institution | Chiba University |
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Principal Investigator |
OKADA Osamu Chiba University, School of Medicine, Instructor, 医学部, 助手 (60177045)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHIDA Yasuhide Chiba University, School of Medicine, Instructor, 医学部, 助手 (40220686)
KATOU Kunihoko Chiba University, School of Medicine, Instructor, 医学部, 助手 (00204462)
KURIYAMA Takayuki Chiba University, School of Medicine, Professor, 医学部, 教授 (20009723)
佐藤 圭一 千葉大学, 医学部, 医員
安田 順一 千葉大学, 医学部, 医員
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| Project Period (FY) |
1992 – 1993
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| Project Status |
Completed (Fiscal Year 1993)
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| Budget Amount *help |
¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1993: ¥400,000 (Direct Cost: ¥400,000)
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| Keywords | Pulmonary microcirculation / In-vivo microscopy / Hypoxic pulmanary vasoconstriction / Isolated perfused lung / Pulmonary capillary / Pulmonary circulation / Pulmonary vascular distensibility / 摘出分離灌流肺 |
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| Research Abstract |
In the pulmonary circulation, pressure and flow are not linearly related. Although our understanding of this relationship is incomplete, much of the nonlinearity is thought to be coused by resistance alterations that result from a cmplex combination of recruitment of new vesselsand distension of already perfused vessels.
To investigate capillary perfusion patterns and pulmonary microvasvlar distensibility , we used videomicroscopy to observe the subpleural pulmonary microcirculation, both in intact dogs and in isolated perfused lobes.
First, elevated pulmonary arterial pressure by airway hypoxia increased the number of perfused capillary segments. Therefore, recruitment in the pulmonary circulation was exclusively a capillary event and essentially absent in arterioles and venules. We showed that one-half of the capillary segments were consistently perfused during at least eight of th enine observations in intact dags and were interconnected to form perferntial pathways across the alveolar wall. We put a balloon in the left atrium to control capillary pressure, and provided th efirst evidence that resistances vary significantly among capillary segments and might be determined by morphological factors, such as diameter to length of individual capillary segments. Moreover, the differences among segmental opening pressure were stable and significantly influenced to the perfusion patterns within alveolar capollary network.
Next, as microvascular pressure was systematically varied between 0 and 30 mmHg, subpleural microvasvular diameters were determined from computer-enhanced images obtained by videomicroscopy. The distensibility of the smallest (39-70 mu m diam) precapillary atrerioles and postcapillary venules were not different from each other.
Those results are thought to be valuable informations for our understanging of hemodynamics and perfusion patterns in pulmonary microcirsulation.
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