Perivascular distribution of APP-immunoreactive axon abnormalities demonstrated here on adjacent sections, one of which (top) was processed for APP immunohistochemistry and the other (bottom) with Masson trichrome stain (images taken from Case 3). Numbers indicate corresponding blood vessels. Note that axonal abnormalities encircle aniline blue (+) thick-walled vessels representing arterioles (#1, 3, 5), but not thin-walled vessels that are venules (#2, 4). (4) is not evident on top section and only its position was marked as such. Size bars: 50 μm.