1. From the School of Veterinary Medicine and Biomedical Sciences, and 2the Redox Biology Center, University of Nebraska-Lincoln, Lincoln, Nebraska; and
2. From the School of Veterinary Medicine and Biomedical Sciences, and 2the Redox Biology Center, University of Nebraska-Lincoln, Lincoln, Nebraska; and 3the Department of Ophthalmology, University of Nebraska Medical Center, Omaha, Nebraska.