Quality control parameters for brain sample microarrays from hippocampus.

Abbreviations: COC, cocaine abuser; CTRL, drug-free control; GAPDH, glyceraldehyde-3-phosphate dehydrogenase *The lower percent present calls in the B chip compared to the A chip is due to the fact that the B chip contains primary probe sets representing EST clusters. As a result overall signal intensities on the B chip are lower which is reflected by higher scaling factors. Note that RNA-QC metrics (including β-actin and GAPDH signal ratios) are consistent across chips. Values were derived from Microarray Analysis Suite version 5.0 analysis (available at http://www.affymetrix.com).