Fig. 1

Vascular permeability induced 1 hour following delivery of 10 Gy peak dose at 10 Gy/s. (A) Permeability of FITC-dextran (150 kDa) is observed as diffuse fluorescence in peak-irradiated regions (P, double-headed arrows) as confirmed by the presence of radiochromic film (RcF). (B) Vascular connectivity from one peak region in A (asterisk) was examined using vessel feature detection revealing intact microvasculature in both peak and valley regions at this time point and shown at a higher magnification in (B’). (C) Semithin section of CAM displays dilation of mesenchyme (edema indicated by blue double arrowheads) in irradiated region relative to out-of-field region with capillary plexus in out-of-field region appearing intact (Ci) while those in the irradiation field are densely congested with erythrocytes and occluded by swelling epithelium (Cii). (D) Ultrastructure of vasculature in the out-of-field region is comprised of elongated, continuous, and tightly associated endothelial (En) and peri-endothelial (Pr) cells as well as a homogenous epithelium (Ep). (E) Ultrastructure of in-field vasculature reveals congested capillaries with signs of endothelial (En) and peri-endothelial (Pr) cell disintegration (i) as well as erythrocyte extravasation across the endothelial gaps (ii; arrowheads). Scale bar in A and B is equivalent to 500 μm, 250 μm in B’ and 1 μm in Ei and Eii.