[1] Mayo Clin, Div Gastroenterol & Hepatol, Rochester, MN 55905 USA
[2] Mayo Clin, Mayo Clin Lib, Rochester, MN USA
[3] Rochester Gen Hosp, Dept Internal Med, Rochester, NY USA
[4] Unity Hosp, Dept Internal Med, Rochester, NY USA
[5] Univ Calif San Diego, Div Gastroenterol & Hepatol, La Jolla, CA USA
[6] 200 First St SW, Rochester, MN 55905 USA