One-dimensional steady continuum model of retraction of pseudopod in leukocytes.
One-dimensional steady continuum model of retraction of pseudopod in leukocytes.
复制标题
白细胞中伪足回缩的一维稳定连续体模型。
DOI：
10.1115/1.3168342
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
Schmid-Schönbein,GW
中科院分区：
文献类型：
--
作者：
Zhu,C;Skalak,R;Schmid-Schönbein,GW
建立了白细胞假足缩回的一维稳态连续力学模型。假设收缩的假足向主细胞体移动，其整体运动可以通过典型的流过白细胞的流管内的细胞质流动来表示。流管近似为具有规定几何形状的无摩擦管。用Maxwell流体和Hookean固体分别模拟了主细胞体和假足细胞质的被动流变特性。假设这两个区域被一个尖锐的界面分开，肌动蛋白凝胶在这个界面上分离，从而改变了它从假足流向主细胞体的流变特性。主动收缩运动的驱动机制被假设为肌动蛋白凝胶的自发变形，类似于但不一定等于众所周知的肌动蛋白-肌球蛋白相互作用。这导致在假足和细胞皮层中产生积极的收缩应力。横向牵引力作用于流管的倾斜壁，并转化为轴向应力梯度，进而驱动流体。管壁上的张力被预应力的皮质壳吸收。推导了控制方程和边界条件。得到了一个解。计算样本数据。理论与实验的比较表明，该模型与观测相吻合。
A one-dimensional steady state continuum mechanics model of retraction of pseudopod in leukocytes is developed. The retracting pseudopod is assumed to move bodily toward the main cell body, the bulk motion of which can be represented by cytoplasmic flow within a typical stream tube through the leukocyte. The stream tube is approximated by a frictionless tube with prescribed geometry. The passive rheological properties of cytoplasm in the main cell body and in the pseudopod are modeled, respectively, by Maxwell fluid and Hookean solid. The two regions are assumed to be separated by a sharp interface at which actin gel solates and thereby changes its rheological properties as it flows from the pseudopod to the main cell body. The driving mechanism responsible for the active retraction motion is hypothesized to be a spontaneous deformation of the actin gel, analogous but not necessarily equal to the well known actin-myosin interaction. This results in an active contractile stress being developed in the pseudopod as well as in the cell cortex. The transverse traction pulls against the inclined wall of the stream tube and is transduced into an axial stress gradient, which in turn drives the flow. The tension on the tube wall is picked up by the prestressed cortical shell. Governing equations and boundary conditions are derived. A solution is obtained. Sample data are computed. Comparison of the theory with experiments shows that the model is compatible to the observations.