Figure 1. Comparison of number of copies of endothelin-1 (ET-1) mRNA in patients and controls. Statistical significance was found for control versus nonproliferative diabetic retinopathy (NPDR; p=0.036), control versus proliferative diabetic retinopathy (PDR; p=0.026), diabetes mellitus (DM) without DR versus NPDR (p=0.005), and DM without DR versus PDR (p=0.007). Boxes and whisker plots present medians±quartiles and minimum-maximum values of copy number per 1 μg total RNA.