Division of Gastroenterology & Hepatology, Mayo Clinic, Jacksonville, Florida, USA

Correspondence to Brian E. Lacy, PhD, MD, Mayo Clinic, Division of Gastroenterology & Hepatology, Davis Building, 6th Floor, 4500 San Pablo Road, Jacksonville, FL 32224, USA. Tel: +1 904 953 6319; fax: +1 904 953 7366; e-mail: [email protected]