Figure 1.

The concept of capture and the influences of vessel type, pretreatment, vessel diameter, and WSR on capture in vivo. (A) Capture in vitro occurs through either of two distinct mechanisms. Leukocytes may attach directly to the endothelium and subsequently initiate rolling interactions, an event called primary capture. Alternatively, a freely flowing leukocyte can transiently interact with a previously rolling leukocyte, and subsequently initiate a rolling interaction with the endothelium immediately downstream of the previously rolling cell. This event is known as secondary capture. (B) RLF, capture, and detachment in arterioles and venules of the mouse cremaster muscle microcirculation after cytokine stimulation of the tissue, and in response to preparation trauma only. Capture represents the number of leukocytes that initiated rolling within the central part of the field of vision without previously having been in contact with the vessel wall. (C) Capture of leukocytes in various situations in the microcirculation plotted against leukocyte detachment from the endothelium (r = 0.843, P < 0.001). Data for venules and arterioles are indicated by dots or circles, respectively. (D) Capture of leukocytes from the free flow was plotted against vessel diameter and WSR. In arterioles, capture of leukocytes to the endothelium occurs in all vessels where leukocyte rolling is observed. In venules, capture is low at low WSR and in vessels of small diameters whereas in larger venules and at higher WSR, capture is prominent.