[1] Clin Baretta, Curitiba, Parana, Brazil
[2] State Univ Campinas UNICAMP SP, Fac Med Sci, Dept Surg, Campinas, SP, Brazil
[3] Univ Fed Parana, Dept Internal Med, Curitiba, Parana, Brazil
[4] Univ Sao Paulo, Sch Med, Gastrointestinal Endoscopy Unit, Hosp Clin, Ave Dr Eneas de Carvalho Aguiar,225,6o Andar, BR-05403010 Sao Paulo, Brazil
[5] Harvard Med Sch, Brigham & Womens Hosp, Div Gasteoenterol Hepatol & Endoscopy, Boston, MA 02115 USA