[1] Univ Fed Rio Grande do Sul, Postgrad Program Sci Gastroenterol & Hepatol, BR-90046900 Porto Alegre, RS, Brazil
[2] Univ Fed Rio Grande do Sul, Pediat Gastroenterol Unit, Hosp Clin Porto Alegre, Fac Med, BR-90046900 Porto Alegre, RS, Brazil
[3] Univ Fed Rio Grande do Sul, Hosp Clin Porto Alegre, Endoscopy Serv, Fac Med, BR-90046900 Porto Alegre, RS, Brazil