1. From the Departments of Integrative Medical Biology, Section for Anatomy, and the2Department of Clinical Sciences, Ophthalmology, Umea° University, Umea°, Sweden; the
2. Institute of Biomedicine and Anatomy, University of Helsinki, Helsinki, Finland; the
3. Institut de Biologie et Chimie des Prote´ines, Universite´ Lyon, Lyon, France; and the
4. Department of Biomedicine, Section for Physiology, University of Bergen, Bergen, Norway.