Effect of EC retraction on matrix TSP exposure and PS-exposing RBC adherence.

EC monolayers were pretreated with buffer (A) or histamine (B), labeled with antibodies to TSP, and viewed by fluorescent microscopy. Histamine-induced EC contraction exposed TSP (B), which is normally cryptic (A). Pretreatment with thrombin (white bar), histamine (striped bar), or EDTA (shaded bar) causes enhanced adherence of PS-exposing RBCs (C). Adherence is reported relative to the adherence of the untreated control (solid bar), which was arbitrarily set to 1. Error bars represent standard error of the means calculated from the absolute values from 4 experiments and normalized relative to the adherence of the buffer-treated control. *Indicates significant differences between PS-exposing RBC adherence to ECs treated with buffer, and thrombin, histamine, or EDTA.