1. Divisions of Gastroenterology, Washington University School of Medicine, St. Louis, MO 63110
2. Biocenter, Division of Cell Biology, Innsbruck Medical University, Innsbruck 6010, Austria
3. Divisions of Endocrinology, Metabolism and Lipid Research, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110
4. Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110
5. Department of Medicine, St. Louis Veterans Administration Medical Center, St. Louis, MO 63106