Fig. 1.

Attenuation of platelet spreading by PF-228. Human platelets were either pre-treated with DMSO (−) or PF-228 (+) (1 μM) for 5 min in suspension before being allowed to settle on a either a fibrinogen or CRP-coated surface. Unbound platelets were washed off and bound platelets fixed. The numbers of platelets bound were counted with the assistance of Image J software and presented as the mean number bound per field of view (±SEM; 5 replicates, n = 3) (A). The platelet surface area was determined from the same samples using NIH Image J software and was recorded as the mean surface area (±SEM; 5 replicates, n = 3). Statistical significance was determined using a two-way ANOVA with Bonnferoni post-test (B). Bound platelets were subdivided into different classes: class 1, compact shape; class 2, filopodial extensions evident; class 3, filopodial extensions evident and some platelet spreading; class 4, fully spread with no filopodia evident. Platelets in each class were expressed as a mean percentage (±SEM; 5 replicates, n = 3) of the total number of bound platelets examined (C).