1. Division of Nephrology, Department of Medicine, Duke University School of Medicine, Durham, North Carolina
2. Duke Clinical Research Institute, Duke University School of Medicine, Durham, North Carolina
3. Renal Section, Durham VA Health Care System, Durham, North Carolina
4. Division of Cardiology, Department of Medicine, Duke University School of Medicine, Durham, North Carolina
5. Department of Biochemistry, Duke University Medical Center, Durham, North Carolina