[1] Univ Fed Rio Grande Sul, Hosp Crianca Conceicao, Pediat Gastroenterol Unit, Fed Dept Hlth, BR-90046900 Porto Alegre, RS, Brazil
[2] Univ Fed Rio Grande Sul, Hosp Clin Porto Alegre, Digest Endoscopy Unit, BR-90046900 Porto Alegre, RS, Brazil
[3] Univ Fed Rio Grande Sul, Pediat Gastroenterol Unit, BR-90046900 Porto Alegre, RS, Brazil
[4] Univ Fed Rio Grande Sul, Hosp Clin Porto Alegre, BR-90046900 Porto Alegre, RS, Brazil
[5] Hosp Crianca Conceicao, Fed Dept Hlth, Dept Pathol, Porto Alegre, RS, Brazil