1 Universitat Autònoma de Barcelona, Bellaterra, Spain.
2 Departament of Internal Medicine, Hospital Universitari Germans Trias i Pujol, Badalona, Spain.
3 Division of Gastroenterology and Hepatology, Department of Medicine and Biochemistry, Indiana University School of Medicine, Indianapolis, Indiana, USA.
4 Division of Gastroenterology and Hepatology, Department of Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA.
5 Roudebush Veterans Administration Medical Center, Indianapolis, Indiana, USA.