Molecular Vision: Pendergrass, Mol Vis 2011; 17:2672-2684. Table 1

Table 1. The extent of loss of DNase II-like acid DNase-beta (DLAD), during aging of C57BL/6 mice.

Age	(Average C_TDLAD – average C_TGapdh)	2-C_TDLAD – C_TGapdh	Mean±SEM	Ratio of old/young
27 months old	8.3	0.0032	0.0036±0.0010	13.1%
	7.6	0.0052
	8.7	0.0024
3 months old	6.0	0.016	0.0272±0.005	13.1%
	5.0	0.031
	5.4	0.024
	4.7	0.038

The mRNA concentration is defined as the PCR threshold cycle time (CT; time when the cDNA fluorescence reaches 1.1× of the baseline fluorescence) as a power of 2. Each individual cDNA sample was normalized to the concentration of the control mRNA, Gapdh. The average CT for Gapdh (control enzyme) was subtracted from the average CT for DLAD (column 2). Because PCR amplification is exponential, the difference in CT s must be converted by a power function (column 3). This relative ratio of [mRNA DLAD]/[mRNA Gapdh] is given by the Equation 2exp -(CT DLAD -CT Gapdh). Comparing the values from four 27 month old lenses to the values from three 3 month old lenses, we find a p value <0.01 indicating that mRNA for DLAD was significantly reduced in the old lenses. SE=standard errors of the mean. The analyses were performed in triplicate on lenses from 3×c57bl/6 young mice at 3 months of age compared to lenses from 4 old mice at 28 months.