Interactions of Ultrasound with Platelets and the Blood Coagulation System
The recalcification time of whole blood is a measure of the time taken to form strands of fibrin in vitro after the addition of enough calcium ions to overcome the effect of the anticoagulant. This time was significantly shortened (i.e. the blood sample rendered more clottable) after the samples had been exposed to continuous wave 1 MHz ultrasound at space averaged intensities within the range 0.065 to 2 W/cm2(1). The blood samples (each 1.5 ml) were contained within a siliconized Pyrex(R) glass tube (1.1 cm i.d. and 1.5 cm long) attached centrally at 90° to a hollow glass stem so that it resembled the letter “T”. The open ends of the glass tube were covered with an acoustically transparent window of cling film held in position by means of rubber O-rings. This sample chamber was mounted in a 37°C water bath on axis with and in the near field of the transducer. The formation of standing waves was minimized by the incorporation of a highly absorbing bath of castor oil at the far end of the exposure tank.
KeywordsHuman Platelet Ultrasonic Irradiation Release Reaction Ultrasonic Cavitation Platelet Suspension
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