Fig. (7) Core membrane fluidity measured using 1,3-Bis-pyrenylpropane (BPP) fluorescent probe. Membrane fluidity in the human monocytic cells (THP-1) was measured after incubation with different activators and inhibitors. Serp-1 (p=0.553), thrombin (p=0.113), or heparin (p=0.158) alone did not cause membrane fluidity changes when compared to control (saline). In the presence of heparin (0.1 U/ml), thrombin increased membrane fluidity sig-nificantly (p<0.001). Serp-1 reversed the heparin-mediated activation, bringing the fluidity level back to a normal level (p < 0.001 compared to heparin activation; p=0.793 on comparison to saline, heparin or thrombin alone without Serp-1). ^*Significantly different (p<0.001) compared to control saline.