[1] Cedars Sinai Med Ctr, Los Angeles, CA 90048 USA
[2] Univ Calif Los Angeles, Los Angeles Vet Adm Ctr Outcomes Res & Educ, VA Greater Los Angeles Healthcare Syst, Ctr Ulcer Res & Educ,Digest Dis Res Ctr, Los Angeles, CA USA
[3] Univ Calif Los Angeles, David Geffen Sch Med, Los Angeles, CA 90095 USA
[4] Univ British Columbia, Vancouver, BC V5Z 1M9, Canada
[5] Harvard Univ, Beth Israel Deaconess Med Ctr, Sch Med, Boston, MA 02215 USA
[6] Univ Calgary, Calgary, AB T2N 1N4, Canada
[7] Univ Chicago, Chicago, IL 60637 USA
[8] Guys Hosp, London SE1 9RT, England
[9] St Thomas Hosp, London, England
[10] Univ Saskatchewan, Saskatoon, SK, Canada
[11] Thomas Jefferson Univ, Philadelphia, PA 19107 USA
[12] Univ Calif San Francisco, San Francisco, CA 94143 USA
[13] Univ Pittsburgh, Pittsburgh, PA USA
[14] Alfred Hosp, Dept Gastroenterol, Melbourne, Vic, Australia
[15] Dartmouth Hitchcock Med Ctr, Lebanon, NH 03766 USA