1. University of Texas Southwestern Medical Center, Dallas (K.S., A.C., T.S., P.H.J., A.K., C.R.A., A.R.).
2. Michael E. DeBakey Veterans Affairs Medical Center, Houston, TX (S.S.V.).
3. Baylor College of Medicine, Houston, TX (S.S.V., C.M.B.).
4. Laboratory Corporation of America Holdings (LabCorp), Morrisville, NC (J.D.O., M.A.C.).
5. University of Groningen and University Medical Center Groningen, The Netherlands (R.P.F.D., E.G.G.).