Figure 2. Tubulin staining of reversibly VWF-adherent platelets visualized in real time.

Platelets were isolated from Vwf ^+/+ (Panels A, C) and Vwf ^−/− (Panels B, D) mouse blood and tubulin staining was studied prior to (Panels A, B) or during perfusion on VWF at 1800 s⁻¹ for 40 min (Panels C, D). Then tubulin staining was monitored in the flow channels by incubation of platelets with tubulin tracker (Panels C, D). Vwf ^+/+ blood contained a majority of discoid platelets (Panels A, C), and no proplatelet was visible in the static sample (Panel A). In contrast, Vwf ^−/− blood (Panel B, D) contained a mixture of dumbbell-shaped proplatelets and platelets with a circular ring of tubulin. Proplatelets were more abundant in the shear sample (Panel D) than in the static sample, with one “figure 8” proplatelet clearly visible (Panel B). Notice that Vwf ^−/− platelets were larger than Vwf ^+/+ platelets. Images were recorded using a Qimaging Rolera camera. Bar = 10 µm.