Cytotoxicity of VBL. Cells were exposed to VBL in the specific growth medium as described in the proliferation assay (Fig1A): pictures on day 4. (A) HUVEC exposed to 1 pmol/L and (B) 2 pmol/L: note detached cells with loss of elongated shape and cytoplasmic swelling. (C) EA.hy926 cells exposed to 1 pmol/L and (D) 2 pmol/L, fixed in 2.5% glutharaldehyde and stained with May-Grünwald-Giemsa: note signs of toxicity as in HUVEC. (E) Human lymphoblastic leukemia T-cells (CEM cells) exposed to 2 pmol/L and (F) 40 pmol/L: different from (E), note many cells with dusty cytoplasm and some cells with nuclear pyknosis. Bar = 30 μm in (A), (B), (E), (F); 16 μm in (C), (D).