dgRTA-induced morphologic changes. HUV-EC-C monolayers were cultured on the collagen IV-coated microporous cell culture inserts and treated as they were in the TEFF assays. SEM images represent (A) naked microporous membranes, (B) untreated control monolayers, (C) monolayers treated with 10⁻⁷ mol/L dgRTA for 96 hours, or (D) monolayers treated with 1 μg/mL cytochalasin D for 15 minutes. All photomicrographs were taken at 500× magnification using a tilt angle of 45°. The bar in (A) represents 50 μm; the original magnifications for (B) through (D) are the same as (A). Arrows indicate exposed pores and arrowheads indicate pores covered by endothelial cells.