Hyperhad

The adhesion experiments were performed as described previously14 (link). Briefly, the monocytes were subjected to laminar flow through a channel (2 mm width and 0.1 mm height) inserted into a well of a 24-well chamber. The shear rate was ~10 s⁻¹; thus, the cells attached to the surface were subjected to a viscous force on the order of 7 pN23 (link). Images were acquired with a video camera (HyperHAD; Sony France, Clichy, France) attached to an Olympus IX 50 inverted microscope with a 10× objective set within a closed box maintained at 37 °C. The pixel size was 1 × 1 μm². Sequences, typically 2 min in duration, were digitized and DivX compressed with a Win-TV digitizer (Hauppauge, France) for subsequent analysis. The films were decomposed into frames using ImageJ software (1.48v; NIH, USA). Subsequently, the TrajFSerie program (written in Java) used these tables to create a file containing the trajectory of each cell. This file was processed with Igor software (Wavemetrics, EUA) to detect and measure the duration of the stops of each cell. The numbers of detectable arrests (remaining for 200 ms or longer) and the numbers of permanent arrests (i.e., arrests lasting 2 min) were thus determined.