Figure 1. The effect of halothane on polymorphonuclear leukocyte (PMN) adhesion to human umbilical vein endothelial cell (HUVEC) monolayers. Some PMNs did bind to unstimulated HUVECs. Significantly enhanced adherence of PMNs was observed with HUVECs stimulated for 10 min with 1 mM H²O²and after stimulation of PMNs with 10 nM N-formyl-methionyl-leucyl-phenylalanine for 15 min. Preincubation of PMNs alone with 1 minimum alveolar concentration halothane (PMN plus halothane) for 40 min completely abolished the increased PMN adhesion in both cases. In contrast, pretreatment of HUVECs alone with halothane (HUVEC plus halothane) did not inhibit adherence. Halothane exerted no greater effect when both PMNs and HUVECs were preexposed (HUVEC plus PMN plus halothane). The results are expressed as the mean +/- SD of five separate experiments. *P < 0.05 compared with baseline adhesion (without stimulation);[dagger] P < 0.05 compared with adhesion during the same conditions in the control group.