[1] LOYOLA MED SCH, HINES, IL USA
[2] VET ADM HOSP, HOUSTON, TX USA
[3] BAYLOR COLL MED, HOUSTON, TX 77030 USA
[4] ST PAUL GASTROENTEROL LTD, ST PAUL, MN USA
[5] ST PAUL GASTROENTEROL LTD, BRADENTON, FL USA
[6] UNIV MISSISSIPPI, MED CTR, JACKSON, MS 39216 USA
[7] CLEVELAND CLIN EDUC FDN, CLEVELAND, OH 44106 USA
[8] ALBERT EINSTEIN MED CTR, NO DIV, PHILADELPHIA, PA 19141 USA
[9] BROWN UNIV, PROVIDENCE, RI 02912 USA
[10] MCGILL UNIV, MONTREAL GEN HOSP, MONTREAL H3G 1A4, QUEBEC, CANADA
[11] MERCY CATHOLIC MED CTR, DARBY, PA USA
[12] UNIV MONTREAL, HOSP ST LUC, MONTREAL H3C 3J7, QUEBEC, CANADA
[13] ALTON OCHSNER MED FDN & OCHSNER CLIN, NEW ORLEANS, LA 70121 USA
[14] SCOTT & WHITE CLIN, TEMPLE, TX USA
[15] SCOTT & WHITE MEM HOSP, TEMPLE, TX 76501 USA
[16] UNIV OTTAWA, OTTAWA CIVIC HOSP, OTTAWA K1N 6N5, ONTARIO, CANADA
[17] DALHOUSIE UNIV, HALIFAX B3H 4H2, NS, CANADA
[18] EMORY UNIV, SCH MED, ATLANTA, GA 30322 USA
[19] VET ADM MED CTR, ATLANTA, GA USA
[20] UNIV MONTREAL, MAISONNEUVE ROSEMONT HOSP, MONTREAL H3C 3J7, QUEBEC, CANADA
[21] UNIV TENNESSEE, CTR HLTH SCI, CTR HLTH SERV, MEMPHIS, TN 38163 USA
[22] VET ADM HOSP, MEMPHIS, TN USA