[1] Stanford Univ, Med Ctr, Dept Pathol, Stanford, CA 94306 USA
[2] Royal Brompton & Harefield NHS Fdn Trust, London, England
[3] Rigshosp, DK-2100 Copenhagen, Denmark
[4] Univ Padua, Padua, Italy
[5] Hop Europeen Georges Pompidou, Paris, France
[6] Univ Calif Los Angeles, David Geffen Sch Med, Los Angeles, CA 90095 USA
[7] Papworth Hosp, Papworth Everard, England
[8] St Orsola Hosp, Bologna, Italy
[9] Mayo Clin, Rochester, MN USA
[10] Columbia Univ, New York, NY USA
[11] Intermt Med Ctr, Salt Lake City, UT USA
[12] Queen Elizabeth Hosp, Birmingham B15 2TH, W Midlands, England
[13] Brigham & Womens Hosp, Boston, MA 02115 USA
[14] Univ Utah, Salt Lake City, UT USA
[15] Univ Pittsburgh, Med Ctr, Pittsburgh, PA USA