[1] Univ Chicago Med, Inflammatory Bowel Dis Ctr, Chicago, IL 60637 USA
[2] Massachusetts Gen Hosp, Crohns & Colitis Ctr, Div Gastroenterol, Boston, MA 02114 USA
[3] Dartmouth Hitchcock Med Ctr, Sect Gastroenterol & Hepatol, Lebanon, NH 03766 USA
[4] Univ Virginia, Dept Med, Charlottesville, VA USA
[5] Univ N Carolina, Dept Med, Div Gastroenterol & Hepatol, Chapel Hill, NC 27515 USA