1. C. C. Paulusma, P. J. Bosma, C. T. M. Bakker, R. P. J. Oude Elferink, Department of Gastrointestinal and Liver Diseases, Center for Liver and Intestinal Research, Academic Medical Center F0-116, Meibergdreef 9, 1105 AZ Amsterdam, Netherlands.
2. G. J. R. Zaman and P. Borst, Division of Molecular Biology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, Netherlands.
3. M. Otter, Department of Biochemistry, Academic Medical Center, Meibergdreef 9, 1105 AZ Amsterdam, Netherlands.
4. G. L. Scheffer and R. J. Scheper, Department of Pathology, Free University Hospital, De Boelelaan 1117, 1080 HV Amsterdam, Netherlands.