Miller D L
Battelle Pacific Northwest Laboratory, Richland, WA 99352.
Ultrasound Med Biol. 1988;14(4):293-7. doi: 10.1016/0301-5629(88)90095-6.
In vitro studies of ultrasonic bioeffects typically employ cell number densities much lower than those present in vivo, which can lead to difficulties in interpretation and extrapolation. In this study, the influence of cell number density on the hemolytic effect of ultrasonic gas-body activation (a low-level form of cavitation) was investigated. Hydrophobic membranes with 4 micron diameter gas-trapping micropores were immersed in saline suspensions of erythrocytes with hematocrits (HCT) from 0.001 to 0.3, and whole blood, and exposed to 1.7 MHz continuous-wave ultrasound in a 37 degrees C saline-filled exposure bath. Significant hemolysis was observed for spatial peak intensities above about 45-90 mW/cm2 for the 16 min exposures. The percentage of cells hemolyzed tended to decrease with increasing hematocrit such that the number of cells hemolyzed, which is proportional to the product of the hematocrit and the percent hemolysis, remained roughly constant. Readily observable in vitro effects may therefore become quite subtle when diluted, as for in vivo conditions, by large numbers of cells.
超声生物效应的体外研究通常采用比体内细胞数量密度低得多的细胞数量密度，这可能导致解释和外推方面的困难。在本研究中，研究了细胞数量密度对超声气体-液体激活（一种低水平的空化形式）溶血效应的影响。将具有4微米直径气体捕获微孔的疏水膜浸入血细胞比容（HCT）为0.001至0.3的红细胞盐水悬浮液以及全血中，并在充满37℃盐水的暴露浴中暴露于1.7MHz连续波超声。对于16分钟的暴露，在空间峰值强度高于约45-90mW/cm2时观察到显著溶血。溶血细胞的百分比倾向于随着血细胞比容的增加而降低，使得溶血细胞的数量（与血细胞比容和溶血百分比的乘积成正比）大致保持恒定。因此，当像体内情况那样被大量细胞稀释时，易于观察到的体外效应可能会变得相当不明显。
