Department of Gastroenterology;
University Hospital of the Canary Islands;
c/Ofra s/n;
La Laguna 38320;
Tenerife;
Spain;
Department of Gastroenterology;
Hospital Universitario Central de Asturias;
Celestino Villamil s/n;
33006 Oviedo;
Principado de Asturias;
Spain;
Research Unit;
University Hospital of the Canary Islands;
c/Ofra s/n;
La Laguna 38320;
Tenerife;
Spain;
Centre for Digestive Diseases;
The General Infirmary at Leeds;
Great George St;
Leeds;
LS1 3EX;
United Kingdom;
Department of Gastroenterology;
Hospital de Clínicas de Montevideo;
Avda.Italia s/n;
Montevideo 11600;
Uruguay;
Division of Endoscopy;
National Cancer Center Hospital;
5-1-1 Tsukiji;
Chuo-ku;
Tokyo 104-0045;
Japan;