Microvascular occlusion and degeneration. Panels A-D show cerebral microvessels of animals that received 3 × 74.5 kPa blast exposures and were perfused 24 hours later. Note the luminal occlusions by the accumulation of heterogeneous amorphous materials (A-D). Panels C and D show different magnifications of a remnant of a microvessel with extensive degenerative changes. An apparent lumen indicated by an asterisk in panel D is the only architectural feature suggestive of a vascular structure. Endothelial and perivascular cell architecture is otherwise unrecognizable. Despite the extensive degenerative changes in the microvessels the surrounding neuropil appears normal. Panels E and F illustrate longitudinally cut microvessels from non-blast exposed control brains. Scale bar: 0.9 μm A-C and E-F; 0.5 μm D.