[1] Univ N Carolina, Chapel Hill, NC USA
[2] Univ Penn, Sch Med, Philadelphia, PA 19104 USA
[3] St Louis Univ, Sch Med, St Louis, MO USA
[4] Univ Chicago, Chicago, IL 60637 USA
[5] Weill Cornell Coll Med, New York, NY USA
[6] Johns Hopkins Sch Med, Baltimore, MD USA
[7] Univ Calif San Francisco, San Francisco, CA 94143 USA
[8] Beth Israel Deaconess Med Ctr, Boston, MA 02215 USA
[9] Henry Ford Hlth Syst, Detroit, MI USA
[10] Scripps Clin, La Jolla, CA 92037 USA
[11] Indiana Univ Sch Med, Indianapolis, IN USA
[12] Univ Colorado Denver Sch Med, Denver, CO USA
[13] Univ Cincinnati, Coll Med, Cincinnati, OH USA
[14] Duke Clin Res Inst, Durham, NC USA
[15] Atlanta Med Ctr, Atlanta, GA USA
[16] Univ Florida, Coll Med, Gainesville, FL USA