Ultrastructural sections of HUVEC under standard culture conditions (A) and after exposure to 0.1 pmol/L VBL (B, C). Cells appear elongated with cytoplasm containing organelles, lipid droplets (arrow) and subcortical microfilaments extending across the cells (arrowheads). (B, C) A bundle of microfilaments (arrow) accumulated to nucleus (N) of a spindle-shaped endothelial cell. Bar (A), (B) = 16.6 μm; (C) = 0.5 μm.