The area fraction was calculated as the number of points falling over amyloid (plaques) or tau (NFTs, NP, or neurites) immunoreactivity divided by the total number of points. Data
from the three groups were compared using the nonparametric exact Kruskal–Wallis test. Pairwise comparisons used the exact Wilcoxon two-sample test Inhibitors,research,lifescience,medical to determine the TSA HDAC supplier relationship between each group. PET scanning conditions Participants underwent PET scanning sessions at baseline (year 1) and annually for up to eight follow-up visits (mean interval 7.2 years). During each imaging session, a resting state PET scan was performed. During rest, participants were instructed to keep their eyes open and focused on a computer Inhibitors,research,lifescience,medical screen covered by a black cloth. For the analyses, scans were censored at the time of clinical diagnosis of dementia onset, documented transient ischemic attack/cerebral infarction, or development of seizures. PET scanning parameters PET measures of regional CBF (rCBF) were obtained using [15O] water. For each scan, 75 mCi of [15O] water were injected as a bolus. Scans were performed on a GE 4096+ scanner, which provides 15 slices of 6.5-mm thickness. Images were acquired Inhibitors,research,lifescience,medical for 60 sec from the time the total radioactivity counts in
brain reached threshold level. Attenuation correction was performed using a transmission scan acquired prior to the emission scans. PET data analysis For each subject, the PET scans were realigned, resliced to a voxel size of 2 × 2 × 2 mm, spatially normalized into standard stereotactic, and smoothed to a full width at half maximum of 12, 12, and 12 mm in the x, y, and z Inhibitors,research,lifescience,medical planes. To control for variability in global flow, rCBF values at each voxel were ratio adjusted and scaled to a mean global flow of 50 mL/100 g/min for each image. The image data were analyzed using Statistical Parametric Mapping (SPM5; Wellcome Department of Cognitive Neurology, London, England), where whole brain voxel
by voxel comparisons determined significant similarities and differences in longitudinal rCBF change between the groups. Group × Inhibitors,research,lifescience,medical Bumetanide time linear comparisons were performed to assess (1) similar changes over time in both ASYMAD and CI groups relative to CN, (2) changes in the ASYMAD group relative to CI and CN, and (3) changes in the CI group relative to ASYMAD and CN groups. All contrasts were adjusted for sex and baseline age at year 1. Significant effects for each contrast were based on the magnitude (P≤ 0.005) and spatial extent (>50 voxels) of activity. To examine the direction and patterns of change in significant regions, rCBF values were extracted from 6 mm spherical regions centered on the local maxima of each region. The rCBF values were then used to calculate differences in baseline (year 1) levels between the groups, and to calculate and compare mean trajectories of change over time for each group using linear mixed models.