[1] Indiana Univ Sch Med, Indianapolis, IN 46202 USA
[2] Univ Puerto Rico, Ctr Comprehens Canc, San Juan, PR 00936 USA
[3] Univ Alabama Birmingham, Dept Med, Birmingham, AL 35294 USA
[4] Hosp Occidente, Santa Rosa De Copan, Copan, Honduras
[5] Vanderbilt Univ, Div Gastroenterol & Hepatol, 221 Kirkland Hall, Nashville, TN 37235 USA
[6] Univ Alabama Birmingham, Div Gastroenterol & Hepatol, Birmingham, AL USA