1. Division of Digestive Diseases, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London, United Kingdom.
2. Cultech Limited, Unit 2 Christchurch Road, Baglan Industrial Park, Port Talbot, United Kingdom.
3. Pharmacology based Clinical Trials, Pennington Biomedical Research Center, 6400 Perkins Rd, Baton Rouge, LA 70808, USA.
4. Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.