In vivo effects of FDP. (A-G) Lung morphology of mice injected with the indicated reagents; H&E. (H-J, M-P) TUNEL stain to detect in situ DNA-fragmentation on corresponding sections. Green fluorescence indicates TUNEL-positive staining. Nuclear counterstain with Hoechst dye (blue). (K,L) Immunostaining for activated caspase-3 (red). Equivalent loading concentrations of D- and E-fragments estimated from average molecular weight of fragments; synthetic peptides were injected to achieve a loading concentration in blood similar to that of D- and E-fragment (∼2 μM). Arrows denote apoptotic endothelium surrounding presumptive blood vessels filled with erythrocytes (determined by examination of phase contrast images). Bars represent 50 μm.