Specificity and quantitation . Each sample was run in duplicate, and values not falling within 50% of their mean were rerun. Specificity of the PCR product was evaluated using the melting curve generated at the end of amplification and by running a 2% agarose gel to visualize the PCR product. Absolute quantitation of mRNA concentration in the original sample was achieved using a standard curve generated for each batch. Each standard curve included two nontemplate controls and eight serial dilutions covering the range of 10 3 to 10 7 molecules/µL. The standards for each gene were prepared as described previously ( Bhat and Epelboym 2004 ). The R 2 for the standard curve was between and ; the plate was rerun if it was < . The ratio of target gene mRNA molecules to 18S mRNA molecules was calculated for each.