Low-Frequency (20 kHz) Ultrasonic Modulation of Drug Action.

We tested the effect of low-frequency ultrasound (LUS, 20 kHz, 4 W/cm2) on the function of rat mesentery and human pulmonary arteries with wire myography. The vessels were induced to contract with either noradrenaline or physiologic saline solution (PSS) with a high potassium concentration (KPSS) and then incubated with capsaicin (2.1 × 10-7 M, TRPV1 [transient receptor potential vanilloid 1] activator), dopamine (1 × 10-4 M, dopamine and α2-receptor activator), or fenoldopam (dopamineA1 receptor agonist, 1 × 10-4 M) with and without glibenclamide (1 µM, KATP [adenosine triphosphate {sensitive potassium channel (ATP)}-sensitive potassium channel] inhibitor and α2-receptor modulator), and insonated. Vessels were incubated in Ca2+-free PSS and induced to contract with added extracellular Ca2+ and noradrenaline. Pulmonary arteries were induced to contract with KPSS and dopamine. Then the vessels were insonated. LUS inhibited the influx of external Ca2+, inhibited the dopamine-induced vasoconstriction in the KPSS (glibenclamide reversible), reduced the capsaicin-induced vasorelaxation, increased the gentamicin-induced vasorelaxation and increased the dopamine-induced contraction in the KPSS in human pulmonary arteries.

Experimental investigation of the determination for the safe operating regime of ultrasound tube-shaped waveguide wire for internal blood vessel debulking.

BACKGROUND: Majority of limb amputations are caused by circulatory disturbances such as vascular occlusions and strictures. Discovery of modern and more advanced ultrasonic interventional vascular debulking methodology would likely save limbs of CVD patients and their lives in an economical way. However, there is a lack of researches regarding the ultrasound's effect on physiological functions of human blood cells. The tube-shaped ultrasound waveguide wire with orifices at its operational end was offered as the alternative to some currently patented interventional thrombosis treatment solutions. OBJECTIVE: To establish the safe operating regime of the proposed device. METHODS: The temperature rise induced by the cavitation process and friction between the waveguide and surrounding fluids was measured and microscopic pictures of human blood were made. RESULTS: Blood insonation lasting 15 seconds, leads to blood clot formation. If insonation continues for 30 seconds some cells are totally destroyed. In addition, the safe operating regime was established. To avoid heating of the environment to the temperature harmful for the medium (blood) and surrounding tissues, is achieved when the system should be on for 40%, and of for 60% of the period of 1 second. CONCLUSIONS: The safe operating regime of the proposed device was established.