Immunohistochemical detection of ASMA and PrPres in scrapie-infected Tg44+/+ transgenic mice at 308 dpi. (a) Overview showing perivascular PrPres amyloid plaques (brown) and ASMA (pink) in cerebral cortex. Note association of PrPres plaques with capillaries (green arrowheads), veins (black arrows) and arteries (green arrows). (b) Higher magnification of perivascular PrPres on a large ASMA-negative vein (black arrow) and a small capillary (green arrowhead). (c) PrPres surrounding an artery (green arrow) and a capillary (green arrowhead). (d) ASMA-positive leptomeningeal artery with thin ablumenal ring of PrPres (green arrow). (e) Leptomeningeal vein (black arrow) with adjacent PrPres. In lower area a small artery (green arrow) and a capillary (green arrowhead) have associated PrPres. Bars: 100 μm (a), 50 μm (b-e).