1. Gastroenterology Unit1and
2. Division of Gastroenterology, CHUV, University of Lausanne, 1011 Lausanne,2 Switzerland
3. Institutes of Veterinary Bacteriology3 and
4. Veterinary Pathology,4 University of Bern, 3012 Bern, and
5. Institute of Clinical Pharmacology,5Inselspital, 3010 Bern,