An In Vitro Assay for Sonothrombolysis Based on the Spectrophotometric Measurement of Clot Thickness.
OBJECTIVE
For improved thrombolysis therapy based on ultrasound irradiation, researchers and practitioners would strongly benefit from an easy and efficient in vitro assay system of thrombolysis activity involving irradiated ultrasound. For the present study, we designed a new in vitro sonothrombolysis assay system using a sheet-type clot.


METHODS
We designed a cell for clot assay, and we confirmed that this clot cell did not significantly intervene in the acoustic field. Using human plasma, we made a sheet-type clot in the cell. Clot thicknesses at 100 points along 4 directions were measured photometrically at a rate of approximately 4 points/s.


RESULTS
The sonothrombolysis effects at 13 levels of ultrasonic intensity were obtained with only one sheet-type clot. With this method, we used a clinically oriented probe at 0.7 and 0.3 W/cm2to confirm that sonothrombolysis took place.


CONCLUSIONS
We successfully established a new, easy, and efficient method for conducting in vitro sonothrombolysis assays. This method involves little intervention of either ultrasound reflection or standing waves in the clot cell. We believe that this new assay method is very useful for fundamental analyses of ultrasound's thrombolysis effects.
Division of Medical Engineering, Research Center for Medical Sciences, the Jikei University School of Medicine, Tokyo, Japan.
Zuojun
Z
Wang
Department of Clinical Pharmaceutics, Nihon Pharmaceutical University, Saitama, Japan.
Yoshikazu
Y
Sawaguchi
Medical Devices Division, Kaneka Corporation, Tokyo, Japan.
Hideo
H
Hirose
Medical Devices Division, Kaneka Corporation, Tokyo, Japan.
Kazumasa
K
Ohara
Medical Devices Division, Kaneka Corporation, Tokyo, Japan.
Shinichiro
S
Sakamoto
Department of Neurology, the Jikei University School of Medicine, Tokyo, Japan.
Hidetaka
H
Mitsumura
Department of Emergency Medicine, the Jikei University School of Medicine, Tokyo, Japan.
Takeki
T
Ogawa
Department of Neurology, the Jikei University School of Medicine, Tokyo, Japan.
Yasuyuki
Y
Iguchi
Division of Medical Engineering, Research Center for Medical Sciences, the Jikei University School of Medicine, Tokyo, Japan.
Masayuki
M
Yokoyama
D006801:Humans; D066298:In Vitro Techniques; D013053:Spectrophotometry / Q000379:methods*; D015912:Thrombolytic Therapy / Q000379:methods*; D013927:Thrombosis / Q000628:therapy*; D014464:Ultrasonic Therapy / Q000379:methods*
acute ischemic stroke; fibrin clot; rt-PA; sonothrombolysis; standing wave