(A, B) Images (original magnification ×200) display patency of postcapillary venules prior to thrombus formation (upper panel) and standstill of perfusion upon light/dye-induced thrombus formation due to complete vessel occlusion (lower panel) in ZPI+/+ (A) or PZ+/+ (B) mice. (C, D) The occlusion times in venules upon induction of GSR or exposure to physiological saline are quantified for ZPI (C) or PZ (D) mouse strains. Data are given as box plots indicating the median with the 25th and 75th percentiles. Mann-Whitney rank-sum test, followed by Bonferroni correction; * p<0.05 vs. saline-treated mice with the same genetic background, # p<0.05 vs. wild-type GSR mice. Abbreviations: PZ, protein Z; ZPI, protein Z-dependent protease-inhibitor; GSR, generalized Shwartzman reaction; TI, thrombus induction. (GSR 4 hours: ZPI+/+ n=11, ZPI−/− n=14, PZ+/+ n=11, PZ−/− n=14; saline: ZPI+/+ n=11, ZPI−/− n=13, PZ+/+ n=12, PZ−/− n=12).