MTX-induced membrane blebbing in BAECs. This figure shows a photomicrograph of BAECs treated with 1.0 nM MTX in the presence of YO-PRO-1 for 50 min at room temperature. The image shown was obtained using Hoffman optics and dual bright-field/fluorescence illumination. Note the intense green fluorescence of the nucleus, indicative of YO-PRO uptake. Fluorescence is also detected in the cytoplasm and membrane blebs.