Fig. 3: Quantification of platelet activation assessed by scanning electron microscopy.

Platelets were incubated for 15 min (light bars) and 60 min (dark bars) under the following conditions: untreated platelets (negative control), treated with KKO/PF4, KKO, PF4, and Ca²⁺-ionophore A23187 (positive control). Final concentrations: 10 µg/ml PF4, 50 µg/ml KKO, and 12 µM Ca²⁺-ionophore. a The fraction of activated platelets (with characteristic shape change, see Fig. 2) normalized by the number of activated platelets present in preparations of control untreated platelets (negative control) taken as 100%. b Mean diameter of platelet bodies (without membrane protrusions) under various experimental conditions. Number of platelets analyzed varied from 100 to 250 for each experimental condition. Statistical analysis was performed using a chi-square test (a) or a two-tailed t-test (b). Asterisks show statistical significance compared with the corresponding negative control values and between 15 and 60 min incubation (marked by a horizontal line). ***P < 0.001; **P < 0.01; and *P < 0.05 compared to a corresponding negative control