1. Department of Laboratory Medicine and Pathology, Hennepin County Medical Center, and University of Minnesota, Minneapolis, MN
2. Division of Cardiology, Department of Medicine, Hennepin County Medical Center and Minneapolis Heart Institute, Abbott-Northwestern Hospital, Minneapolis, MN
3. Mayo Clinic and Mayo College of Medicine, Rochester, MN
4. Servei Bioquimica, IBB-Hospital de la Santa Creu i Sant Pau and Department de Bioquimica i Biologia Molecular, Universitat Autònoma, Barcelona, Spain