Shammari M A, Watmough D J, Kerr C L, Gregory D W, Wheatley D N
Department of Bio-Medical Physics, Foresterhill, Aberdeen, Scotland, UK.
Int J Hyperthermia. 1990 May-Jun;6(3):571-80. doi: 10.3109/02656739009140953.
Hyperthermic treatment of HeLa cells in suspension combined with ultrasound irradiation produced alterations to the cell surfaces. The changes induced were related to ultrasound intensity in the standing wave and to heat treatments between 37 and 45 degrees C. Two transducers were used, driven at resonant frequencies of 0.75 and 1.5 MHz, and producing peak intensities up to 7 W/cm2. These intensities produced a negligible rise in temperature of the cell suspension medium. Ultrastructural damage in standing wave fields, as seen by scanning electron microscopy, progressed through stages. The first stage was characterized by the loss of microvilli and smooth appearance of the cell surface, e.g. after insonation at 41.5 degrees C for 10 min; damage increased to a final stage where the surface appeared heavily pitted and porous, with the cells showing signs of disintegration, e.g. after insonation at 45 degrees C for 10 min. The monitoring of ultrasound-induced cavitation suggested that damage was caused by bubble oscillations, not collapse cavitation. Shearing stresses accentuated by hyperthermia were considered the probable cause of such damage. Coulter counter studies of cell size distribution showed that the extent of cell damage depended on the geometry of the vessel in which insonation was carried out.
对悬浮状态的HeLa细胞进行热疗并结合超声照射会导致细胞表面发生改变。所诱导的变化与驻波中的超声强度以及37至45摄氏度之间的热处理有关。使用了两个换能器，其驱动共振频率分别为0.75和1.5兆赫兹，产生的峰值强度高达7瓦/平方厘米。这些强度使细胞悬浮培养基的温度升高可忽略不计。通过扫描电子显微镜观察，驻波场中的超微结构损伤会经历多个阶段。第一阶段的特征是微绒毛丧失且细胞表面外观光滑，例如在41.5摄氏度下超声处理10分钟后；损伤会增加到最终阶段，此时表面出现大量凹坑和孔隙，细胞呈现出解体迹象，例如在45摄氏度下超声处理10分钟后。对超声诱导空化的监测表明，损伤是由气泡振荡而非空化崩溃引起的。热疗加剧的剪切应力被认为是造成此类损伤的可能原因。对细胞大小分布的库尔特计数器研究表明，细胞损伤程度取决于进行超声处理的容器的几何形状。
