1. Department of Ophthalmology, School of Medicine, Sapporo Medical University, Sapporo, Japan.
2. Department of Cardiovascular, Renal and Metabolic Medicine, and School of Medicine, Sapporo Medical University, Sapporo, Japan.
3. Department of Cellular Physiology and Signal Transduction, School of Medicine, Sapporo Medical University, Sapporo, Japan.