SEM observations of HUVECs (A-B) and BECs STR-4 (C-D) treated with 100 nM di-h-HALI for 120 min. (A) HUVECs exposed to di-h-HALI show significant signs of cell contraction; i.e. the cytoplasm is retracted and numerous fine cytoplasmic extensions appear (arrows). Scale bar, 5 μm. (B) High magnification image of the cytoplasm shows a smooth surface and the lack of fenestrated structures (compare with Fig. 2C for the difference with LSECs). Scale bar, 2.5 μm. (C-D) di-h-HALI treated BECs STR-4 show features similar to those seen in A and B (scale bars [C] 5 μm, [D] 2.5 μm).