Luminal alterations in the microvasculature following blast exposure. Transverse section of a control microvessel (A) with its general ultrastructural morphology. Also shown are microvessels from animals that received either one (B) or three (C) 74.5 kPa blast exposures and were sacrificed 24 hours later. Note the circular lumen of the normal vessel (A). By contrast the luminal circularity has been lost in the microvessels shown in B and C. Endothelial cell nuclei are labeled with asterisks. Astrocytic processes (A) are indicated in panels A and C. In panels B and C, the endothelial cell nuclei are intact although the microvessel walls (arrows in panels B and C) are abnormally electron dense. The surrounding neuropil appears otherwise normal. Scale bar: 2 μm.