Representative ultrastructural analysis of α-Gal A-deficient and wild-type mouse brain. Ultra-thin sections of the cerebellum (CB; panels a, b, d, e, g, h) and cortex (CTX; panels c, f, i) of 21 month-old α-Gal A hemizygous (-/0; panels d-i) and α-Gal A wild-type (+/0; panels a-c) mice were prepared for electron microscopic analysis. Brain ultrastructure from the α-Gal A +/0 mouse exhibited normal appearing blood vessels (panel a) and perikarya (panel b) and neuronal cells with normal appearing nuclei and cytoplasm (panel c). The endothelial cell lining a blood vessel in α-Gal A -/0 cerebellum contains a prominent inclusion (panel d; panel g represents inset box) exhibiting electron densities (arrowheads). In both cerebellum (panel e; panel h represents inset box) and cortex (panel f; panel i represents inset box) there appeared numerous lipopigment aggregates consisting of lipid droplets associated with electron-dense osmiophilic material. Scale bars = 500 nm.