FIGURE 4.

Surface labeling of resting and convulxin+thrombin (CVX+Thr) activated platelets using immunogold technique. CD41a antigen and factor XIII A subunit (FXIII‐A) are represented by 10 nm and 15 nm gold particles, respectively. A few 15 nm gold particles are depicted by small red arrows; for comparison a few 10 nm gold particles are indicated by small black arrows. A, Non‐stimulated whole platelet, (B) higher magnification of the selected area shown in (A), (C) a CVX+Thr stimulated whole platelet, (D) higher magnification of the selected area shown in (C). E–H, Microparticles formed from CVX+Thr activated platelets, (E, F) microparticles labeled for CD41a and cFXIII demonstrate at least partially intact membrane, (G, H) cFXIII positive microvesicles without CD41a membrane labeling. The images are representative of experiments performed with platelets from three different donors