Red Cell Rheology in Pulsative Flow

红细胞的流动特性影响循环血液的流变学特性。然而，对于脉动剪切流这一动脉生理环境下的红细胞行为，目前还知之甚少。为此，我们利用自制的红细胞流变仪和脉动流系统，对脉动流中红细胞的流变特性进行了研究。(1)为了揭示红细胞变形对剪切应力快速变化的响应，用流变仪观察了稀释悬液中红细胞变形的时间依赖性过程。剪切应力正弦调制。在高于2 Hz的调制频率下，在正弦调制的剪切应力的上相中检测到延迟响应。反应受（i）细胞内粘度，（ii）膜硬度，和（iii）细胞内钙含量的影响。(2)利用计算机控制的脉动剪切流系统，研究了红细胞压积对脉动剪切流中红细胞变形的影响。(i)随着红细胞压积的增加，变形增强。(ii)时间依赖性的红细胞变形表明，形状恢复到双凹形状的脉动剪切应力的下降阶段延迟在高红细胞压积。(3)本文利用直径为250 μ m的刚性管脉动流系统研究了红细胞变形对脉动流压力-流量关系的影响。用压力传感器在沿管的沿着两点处测量侧向压力，以测量两点之间的压力传递效率。结果表明，悬浮液的粘度，而不是红细胞的变形能力，影响的压力传递的效率。

The flow properties of red cells affect the rheological characteristics of circulating blood. However, a little is known about red cell behavior under the pulsative shear flow which is physiological circumstance in arteries. Therefore, we studied the red cell rheology in pulsative flow with a rheoscope and a pulsative flow system built in our laboratory.(1) To reveal the response of red cell deformation to a rapid change in shear stress, the time-dependent process of red cell deformation in a diluted suspension was observed with a rheoscope. Shear stress was modulated sinusoidally. At a modulation frequency of above 2Hz, the retarded response was detected in the up-phase of the sinusoidally modulated shear stress. The response was affected by (i) intracellular viscosity, (ii) membrane stiffness, and (iii) intracellular calcium content.(2) The effect of hematocrit on red cell deformation in pulsative shear flow was studied with the pulsative shear flow system controlled by a computer. (i) The enhancement of deformation was detected with increasing hematocrit. (ii) The time dependent red cell deformation showed that shape recovery to biconcave shape in the down phase of pulsative shear stress was retarded at high hematocrit.(3) The effect of red cell deformation on the pressure-flow relationship of pulsative flow was studied with the pulsative flow system equipped with a rigid tube of 250 um in diameter. Lateral pressure was measured at two points along the tube with pressure transducers to measure the efficiency of pressure transmission between the two points. It was revealed that suspension viscosity, but not red cell deformability, affected the efficiency of the pressure transmission.