1987 Fiscal Year Final Research Report Summary
Quantitative Analyses of the Atherosclerotic aorta in Watanabe Hereditary Hyperlipidemic(WHHL) Rabbits.
| Project/Area Number |
60480238
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Circulatory organs internal medicine
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| Research Institution | National Cardiovascular Center |
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Principal Investigator |
HASEGAWA Masamitsu National Cardiovascular Center Research Institute, Chairman, 研究部, 部長 (30020738)
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| Co-Investigator(Kenkyū-buntansha) |
WATANABE Yoshio Kobe University, School of Medicine, Associate Professor, 医学部, 助教授 (00031401)
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| Project Period (FY) |
1985 – 1987
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| Keywords | Atherosclerosis / Pressure pulse wave / WHHL rabbit / Atheromatous plaque / Wall thickness / Stress-strain curve / 弾性率 |
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| Research Abstract |
Our project was aimed to obtain informations necessary to understand the severity of atherosclerosis quantitatively. For this purpose, we analyzed the pressure pulse waves along the aorta in inherited hyperlipidemic(WHHL) rabbits with different ages with special reference to rheological properties and morphological features of the aortic walls. Methods: After intravenous injection of pentobarbital(25mg/ml), a microtip pressure transducer was placed into the aortic arch through the left carotid artery. Another transducer was inserted into the right femoral artery and advanced to the abdominal aorta and then to the thoracic aorta. Pressure pulse waves were simultaneously determined at two microtip sites. Longitudinal and circumferential strips 5mm wide were made from the excised thoracic aorta and were subjected to the stress-strain test. On the other hand, the area of atheromatous plaques attached on the intimal surface was measured at five aortic portions by means of an area computing
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device.
Results and Discussions: Pressure pulse waves at each aortic portion showed an increase in amplitude of the percussion wave with advancing age, followed by a gradual disappearance of dicrotic notches and dicrotic waves. A positive relationship was found between the wall thickness and the the month of age with the correlation coefficient of 0.66(p<0.01). Elastic moduli at the stresses of 5x10^5 and 10^6dyn/cm^2 calculated from the stress-strain curve increased significantly with advancing age in the longitudinal and circumferential strips. Therefore, age-related changes in the pressure pulse waves were closely related to the increased wall thickness in addition to the increased elastic modulus due to the compositional changes in the wall. The earliest atheromatous plaques appeared in the aortic arch of WHHL rabbits aged two months. Early lesions were located at the origin of aortic branches with specific anatiomical sites and shapes indicating the rheological contribution of the local blood flow properties to the early atherogenesis in the aorta. Less
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