1. Department of Molecular Biomedicine Centro de Investigación y de Estudios Avanzados del I.P.N. Mexico City Mexico
2. Department of Internal Medicine Hospital General Ticomán Mexico City Mexico
3. Experimental Laboratory for Neurodegenerative Diseases Instituto Nacional de Neurología y Neurocirugía “Manuel Velazco Suárez” Mexico City Mexico
4. Research Department Hospital Regional “Licenciado Adolfo López Mateos” (ISSSTE) Mexico City Mexico
5. Service of General Surgery Hospital “Ángeles Lindavista” Mexico City Mexico