Figure 4.

Characterization of regional white matter (WM). (A) There is marked rarefaction (pale areas) indicative of myelin loss of the subcortical WM and throughout the centrum semiovale (lower half of figure). Darker areas indicate relative preservation of WM myelin. The relatively preserved areas tend to be around blood vessels (H&E). (B) Centrum semiovale showing marked rarefaction and myelin loss. The white matter in close proximity to blood vessels is better preserved or is less affected by the disease process (H&E). (C) Cerebral WM around small blood vessels and capillaries is less rarified and has more numerous oligodendroglia; the surrounding rarefied WM is less cellular with sparse glia (H&E). (D) Internal capsule WM is mostly intact but there are scattered patches of rarefaction (H&E). (E) WM tracts in the striatum are relatively preserved (H&E). (F) Centrum semiovale is rarified with marked myelin and oligodendrocyte loss (H&E). (G) Luxol-fast blue/Periodic acid Schiff (LFB/PAS) stain reveals rarefied pale-blue myelin in centrum semiovale and perivascular areas of better-preserved WM myelin. (H) Axons near blood vessels are also better preserved (Bielschowsky preparation). (I) Axonal loss is greater in regions with more prominent WM rarefaction and myelin loss (Bielschowsky). (J) Glial fibrillary acidic protein (GFAP)-immunoreactive fibrillary astrocytes are present in cortical layers V and VI. (K) In contrast, there is a lack of prominent astrogliosis in most regions of the subcortical WM and centrum semiovale, including most of the U fibers (GFAP). (L) Laminar, fibrillary astrogliosis in cortical layers I, V and VI. Laminar astrogliosis of layer III, which often accompanies gliosis in layer V, is not present. (GFAP). (M) Laminar mineralization of cortical layers I and II corresponds to the laminar astrogliosis (von Kossa stain for calcium). Original magnification: A, J, L, M, 2x; B–E, G, K, 4x; C, F, 10x; H, I, 20x.