MECHANICAL PROPERTIES OF WHITE BLOOD CELLS

这些项目的主要目的是研究中性粒细胞运动的机制。这是通过机械地表征细胞运动的三个主要组成部分：粘附、皮层重排和细胞体收缩，以及表征各种运动反应的信号传导，如假足的形成、运动、游离胞质钙的释放等来完成的。使用的实验技术是微移管操作结合视频显微镜和一种新的微移管技术，称为生物界面探针。该技术可用于测量单分子黏结强度，以及探测细胞表面形貌和皮质张力。在过去的一年里，我们测量了静息中性粒细胞的皮质张力，并在已知会影响皮层亚表层硬度的刺激剂（从fMLP和细胞松弛素d开始）的刺激下继续进行这些实验。我们还研究了胞质钙对中性粒细胞运动反应的影响。我们的计划是继续这些实验，并开始测量粘附分子键的强度，重点是l -选择素。在这项工作中，我们使用来自静脉血的人类中性粒细胞以及来自手指刺破的细胞。这些单元将在整个赠款期间使用。我们预计将继续进行大约五年的实验。献血者总数预计在20至30人之间，迄今已有11人献血者。这不是一个多中心项目或临床试验。

The major goal of these projects is to study the mechanisms of neutrophil motility. This is done by mechanically characterizing the three major components of cell motility: adhesion, cortical rearrangement and cell body contraction, and by characterizing the signaling of a variety of motility responses, such as pseudopod formation, locomotion, release of free cytosolic calcium, etc. The experimental techniques used are micropipet manipulation combined with video microscopy and also a new micropipet technique called the biointerface probe. This technique can be used to measure single molecular adhesive bond strengths, as well as to probe cell surface topography and cortical tension. During the past year, we have measured the cortical tension of the resting neutrophil and are continuing to perform these experiments upon stimulation by agents that are known to affect the stiffness of the sub-surface cortical layer, beginning with fMLP and cytochalasin D. We have also examined the effects of cytosolic calcium on the neutrophil motility response. Our plans are to continue these experiments and also to begin making measurements of adhesion molecule bond strengths, with emphasis on L-selectin. In this work, we use human neutrophils from venous blood as well as cells from finger pricks. These cells will be used for the entire duration of the grants. We expect to continue the experiments for approximately another five years. The total number of blood donors is expected to be in the range of 20 to 30, with 11 donors to date. This is not a multi-center project or a clinical trial.