1. Instituto de Investigaciones Bioquímicas de La Plata-Pathology B (P.C.R., R.G.G.), 1900 La Plata, Argentina
2. Histology B (P.C.R., G.M.C., R.G.G.), 1900 La Plata, Argentina
3. Faculty of Medicine, and Veterinary Histology (C.G.B., A.M.F.), 1900 La Plata, Argentina
4. Institute of Anatomy (G.O.Z.), Faculty of Veterinary Medicine, University of La Plata, 1900 La Plata, Argentina
5. Centre National de la Recherche Scientifique Unité Mixte de Recherche 8147 (M.D.), Université Paris Descartes, Hôpital Necker, Paris 75015, France