1. From the Department of Ophthalmology, University Hospital, Sart-Tilman, Lie`ge, Belgium; the
2. Laboratory of Tumor and Development Biology and the
3. Center for Transgene Technology and Gene Therapy, Katholieke Universiteit Leuven, Leuven, Belgium; and the
4. Department of Ophthalmology, Middelheim Hospital, Antwerpen, Belgium.
5. Center for Cellular and Molecular Neurobiology, University of Lie`ge, Lie`ge, Belgium; the