Fig. 1.

A: effect of passage number (P) on 3-min subendothelial accumulation of the 66- to 69-kDa FITC-avidin tracer [expressed in relative fluorescence units (RFU)], measured by a scanning fluorimetric plate reader. Values are means + SD; n = 10 isolations. B: subendothelial accumulation of FITC-avidin as a function of time. Tracer fluorescence was measured by confocal microscopy of a living monolayer. Tracer was added to the well at time ≈ 9 s. A second-order polynomial was fitted to the data.