4P-selectin blockade inhibits endothelial protein tyrosine phosphorylation in ventilation stress. anti-P-sel mAb, anti–P-selectin monoclonal antibody, RMP-1 (20 μg/ml). α-tyrP, anti-phosphotyrosine; HV, high tidal volume; WB, whole blood perfusion; Rec-WB, reconstituted whole blood perfusion; DB, perfusion with leukocyte- and platelet-depleted blood. (A and B) Representative anti-phosphotyrosine blot of lysates of endothelial cells derived from lungs ventilated and perfused for 2 h as indicated. Arrows indicate prominent bands. Coomassie staining is on duplicate gels. Molecular weights are indicated on the left. (C and D) Bars represent band densities (tyrosine phosphorylation/protein ratios). C: solid bars indicate Rec-WB; open bars indicate DB. D: solid bars indicate WB; open bars indicate WB + anti–P-sel mAb. n = 6 (A) and 3 (B). Mean ± SE. *P < 0.05 by paired t test against left bar.