HUVEC vessels with either wildtype (WT, no cytoplasmic reporter) or a 50/50 mixture of untransfected cytoplasmic-tdTomato and cytoplasmic-eGFP transfected with si-Flt1 were examined by time-lapse microscopy. Stable connection (arrow) is noted. Inset, high magnification first frame showing a stable connection. Scale bar, 25 μm (lower right); time, hrs:mins (lower left).