Nakajima T, Rhee J G, Song C W, Onoyama Y
University of Minnesota Medical School, Department of Therapeutic Radiology-Radiation Oncology, Minneapolis 55455.
Int J Hyperthermia. 1992 Sep-Oct;8(5):679-87. doi: 10.3109/02656739209038003.
Effects of a second heating on blood flow in the liver and cardiac output were studied in Fischer rats. Heating was done by an experimental capacitive heating device using 8 MHz radiofrequency. Thermometry was performed at seven points around the liver with thermocouples. Blood flow and cardiac output were measured with the radioactive microsphere method. The liver was preheated for 30 min at 41 or 43 degrees C, and then reheated 1-7 days later at 41 degrees C for 15 min. Hepatic arterial blood flow, portal venous blood flow and the cardiac output were measured immediately before and at the end of the reheating. Heating the liver at 41 degrees C for 15 min without preheating slightly increased the hepatic arterial blood flow, and reheating 1-7 days after the first heating caused a greater increase in the hepatic arterial blood flow. Increase in hepatic arterial blood flow caused by reheatings pointed to the development of thermotolerance or thermal adaptation in the hepatic artery. When the liver was heated at 41 degrees C for 15 min without preheating, the portal venous blood flow remained almost unchanged 1-7 days after the heating. On the other hand, a reheating at 41 degrees C for 15 min applied 1-7 days after the preheating reduced the portal venous blood flow. Reduction in portal venous blood flow was approximately parallel to reduction in cardiac output by reheating, pointing to the existence of a causal relationship. Reduction in portal venous blood flow by reheating may also be, in part, due to the decrease in the splanchnic blood flow resulting from a systemic adaptation to the heat stress.
在Fischer大鼠中研究了二次加热对肝脏血流和心输出量的影响。加热通过使用8MHz射频的实验性电容加热装置进行。用热电偶在肝脏周围的七个点进行温度测量。用放射性微球法测量血流和心输出量。将肝脏在41或43℃下预热30分钟，然后在1-7天后在41℃下再加热15分钟。在再加热之前和结束时立即测量肝动脉血流、门静脉血流和心输出量。在不预热的情况下将肝脏在41℃下加热15分钟会使肝动脉血流略有增加，并且在第一次加热后1-7天进行再加热会使肝动脉血流有更大的增加。再加热引起的肝动脉血流增加表明肝动脉中耐热性或热适应性的发展。当在不预热的情况下将肝脏在41℃下加热15分钟时，加热后1-7天门静脉血流几乎保持不变。另一方面，在预热后1-7天进行41℃下15分钟的再加热会使门静脉血流减少。门静脉血流的减少与再加热导致的心输出量减少大致平行，表明存在因果关系。再加热引起的门静脉血流减少也可能部分归因于全身对热应激适应导致的内脏血流减少。
