1. Department of Cardiology; Thoraxcenter, University Hospital Groningen; P.O. Box 30.001, 9700 Groningen The Netherlands
2. Department of Internal Medicine, Division of Medical Oncology; University Hospital Groningen; P.O. Box 30.001, 9700 Groningen The Netherlands
3. Department of Internal Medicine, Division of Clinical Immunology; University Hospital Groningen; P.O. Box 30.001, 9700 Groningen The Netherlands
4. Department of Internal Medicine, Division of Gastroenterology and Hepatology; University Hospital Groningen; P.O. Box 30.001, 9700 Groningen The Netherlands