1. Duke University, Durham, NC 27708, USA
2. Duke Clinical Research Institute, PO Box 17969, Durham, NC 27715, USA
3. University of Brescia, Piazza del Mercato, 15, Brescia BS, Italy
4. Brigham & Women's Hospital, 75 Francis St, Boston, MA 02115, USA
5. University of Groningen, 9712 CP Groningen, The Netherlands
6. University of California at San Francisco (SF) & SF Veterans Affairs Medical Center, 500 Parnassus Ave, San Francisco, CA 94143, USA