Fig. 2. Shear flow-induced cell motility. Cells were submitted to a 1 Pa shear stress and monitored under dark field illumination at a 2.5x magnification for 10 minutes. A set of representative cell tracks is shown superimposed over the first image recorded. Each track starts on the cell identified by the indicated number and ends at the free end of the line. Scale bar, 100 µm. Arrow points into the flow direction. (A) Untreated cells. These data correspond to Movie 1. (B) In the presence of 20 µg ml^–1 CIPC. These data correspond to Movie 2. (C) Example of individual cell track analysis. The instant velocity and angle with respect to flow of the cells denoted 1, 2 and 3 in (A) were calculated according to Eqn 2 and represented in orthoradial coordinates. Left: speed modulus as a function of time. The dotted lines indicate the average speed modulus. Right: speed angle as a function of time. The solid lines represent portions of straight-line movements. The dotted lines indicate cell turns.