ANALYSIS OF CELL-MOVEMENT

  • 1 January 1984
    • journal article
    • research article
    • Vol. 10  (1) , 61-77
Abstract
The methods of statistical physics were applied to the analysis of cell movement. Human leukocytes (granulocytes) were observed using time-lapse photography. The center of gravity of a cell, variations of cell shape and cell orientation were investigated. This analytical description leads to a better understanding of cell movement. Stationary motion of a cell is described by the anisotropy of the cell shape. The cell displacement can be characterized by 3 different types of movement: the persistent mode where the cell moves away from an arbitrary chosen origin with its track velocity; the diffusion mode where the cells become dispersed in space by a random walk process; and the drift mode where the cell moves with a drift velocity in a concentration gradient of chemoattractant molecules. The chemokinetic response is described by the diffusion constant D (= 240 .mu.m2/min) and the track velocity vc (= 30 .mu.m/min). The chemotactic response is described by the degree of orientation P1 (= 0.8), which is identical with the McCutcheon index and the chemotropism index. Cell movement can be described by elementary moving states, and the life time of such a moving state is 0.5 min. The survival probability of the moving state is determined by an internal program. It is not described by a stochastic process. The angular change in moving direction is also programmed, as the square root of the mean square angular change is .+-. 50.degree.. The plus and minus direction are equally probable in a chemokinetic response. However, in a chemotactic assay the plus and minus directions are not equally probable. The information transfer from the chemotactic gradient to the migrating cell apparently is 1 bit/change in moving direction. A disturbance in this information transfer leads to an order-disorder transition. Furthermore, it was found that the migrating cell exhibits a directional memory of 75 s.

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