| Project/Area Number |
04807064
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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 |
Circulatory organs internal medicine
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| Research Institution | Osaka University (1994)
National Cardiovascular Center Research Institute (1992-1993) |
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Principal Investigator |
BEPPU Shintaro Osaka Univ.Med.School, School of Allied Health Sciences Professor, 医学部・保健学科医用物理学, 教授 (40113500)
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| Co-Investigator(Kenkyū-buntansha) |
MIYATAKE Kunio National Cardiovascular Center, Hospital, Director, 内科心臓血管部門, 部長
MATSUDA Hisao National Cardiovascular Center, Research Institute Stuff, 循環動態機能部, 室員 (30229489)
SAITO Koji Suzuka Univ.Med.Science and Technology, Professor, 教授 (00261040)
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| Project Period (FY) |
1992 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1994: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1993: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1992: ¥800,000 (Direct Cost: ¥800,000)
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| Keywords | coronary artery / thrombus / recanalization / ultrasound / ultrasonic disruption / catheter |
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| Research Abstract |
It has been revealed that blood clot made in vitro was broken by ultrasound radiation from the ultrasound tip as thin as 3mm in diameter, in which the ultrasound frequency was 20KHz and the power was 1 Watt. Several self-made thin transducer was examined its power in a water bath. Direction and magnitude of the ultrasound power in the water could be visualized using solution diffused by microbubbles. After adjusting the ultrasound frequency to be maximize its effect, the transducer was applied to examine whether the transducer could enhance the thrombolysis in vitro. Dry weight of the clot was less by combination use of ultrasound radiation and Urokinase than that by sole use of Urokinase. This ultrasound effect is enhanced under presence of microbubbles, probably due to cavitation phenomenon. Long-life microbubbles are needed, while ordinal microbubbles are easy to be solved into water or blood. We developed a new agent of stable microbubbles, which was made from dodecafluoropentane. Its durability was examined in canines by echocardiography. The solution of dodecafluoropentane was injected into the peripheral vein and the myocardial opacification was evaluated. Using a dosage over 0.5ml/kg, the myocardium was clearly opacified for long period as over 10 to 50 minutes. Weconclude that the combination use of microtransducer of ultrasound and microbubbles will enhance the thrombolysis in vivo.
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