[1] Mayo Clin & Mayo Fdn, Rochester, MN 55905 USA
[2] Univ Western Ontario, London, ON, Canada
[3] Univ Chicago, Chicago, IL 60637 USA
[4] Univ Berlin, Klinikum Charite, Schwerpunkt Gastroenterol Hepatol & Endokrinol, Berlin, Germany
[5] Huddinge Univ Hosp, S-14186 Huddinge, Sweden
[6] Hop St Louis, Paris, France
[7] CUNY Mt Sinai Sch Med, New York, NY 10029 USA
[8] Univ Hosp Gasthuisberg, B-3000 Louvain, Belgium
[9] Univ Regensburg, D-8400 Regensburg, Germany
[10] Robert Bosch Krankenhaus, Stuttgart, Germany
[11] Dept Community Hlth Sci, Calgary, AB, Canada