Silver-stained image and corresponding fluorescent image showing transmigrating PMNs.

(A) Transmigrating PMNs preferentially locate near tricellular corners, as shown in silver-stained micrograph viewed under bright-field optics. The endothelial borders as well as the locations of PMNs (arrowheads) are clearly visible under these conditions. (B) The fluorescence image (380 nm) shows the location of fura-2–stained endothelial cells. Because neither unstained PMNs nor the EC boundary is visible under fluorescence optics, their locations are identified by direct comparison between (A) and (B). Bar equals 30 μm.