1. Post-graduate Program of the Federal University of Sao Paulo. Department of Gastroenterology, Federal University of Sao Paulo, Botucatu Street, 740, Sao Paulo 04023-900, Brazil
2. Professor Alberto Antunes University Hospital, Federal University of Alagoas, Lourival Melo Mota Avenue, Maceio-Alagoas 57072-970, Brazil
3. Institute of Medical Assistance of the Hospital do Servidor Publico Estadual de São Paulo, Pedro de Toledo Street 1800, São Paulo 04038-034, Brazil
4. Department of Gastroenterology, Federal University of Sao Paulo, Botucatu Street, 740, Sao Paulo 04023-900, Brazil