BACE1 and Alzheimer disease: To determine the quantitative relationships between BACE1 and βIII-tubulin immunoreactivities within the peri-plaque halo, we calculated the ratio of BACE1 to βIII-tubulin immunofluorescence intensities in dystrophic neurites (defined by high BACE1 signal) around plaques and in regions of normal neuropil distant from plaques for the AD cases (Fig. 3b).