Fig. 1.

Normalized concentrations of rhodamine 123 (R123) and tetramethylrhodamine ethyl ester (TMRE) in medium surrounding pulmonary arterial endothelial cell-coated beads vs. time. Medium containing R123 (10, 30, and 100 nM) or TMRE (10, 30, and 100 nM) was added to cell-coated beads, and dye concentrations in medium ([R_e]) were measured over time. Measured dye concentrations were normalized to initial dye concentrations ([R123_e] or [TMRE_e]). Also shown are normalized R123 and TMRE concentrations in medium over time in the absence of cells. Symbols represent representative data from 3 experiments without cells and 4 experiments with cells for each dye concentration. Solid line, Eq. 8 fit to data; dashed lines, model predictions using Table 1 parameter values.