A–B: Six-μm thick, mirror-sectioned serial sections from frontal neocortex of AD brain doubly stained for CLAC (blue, anti-pyroGlu113) and thioS (green) (A) or for CLAC (blue, anti-pyroGlu113) and Aβ40 (red, BA27) (B). Note that most of the thioS-positive areas in A are overlapped and included within the Aβ40-positive areas in B, and occasional CLAC/Aβ40-positive SP (visualized in purple in B; eg, a SP in the lower left) are thioS-negative in A. Bar, 50 μm. C: Relative ratios of CLAC-positive, thioS-negative (blue), CLAC- and thioS-positive (light blue) and CLAC-negative, thioS-positive (green) SP areas in sections stained as in A (mean value in eight AD cases in which numerous thioS-positive SP were observed) are shown. The total areas (100%) correspond to those positive for CLAC plus thio-S.