1. Programa de Patología, Campus Oriente, Instituto de Ciencias Biomédicas, Facultad de Medicina (R.A.R., J.A.L., E.M.S.), International Center for Andean Research, Universidad de Chile, Santiago, Chile
2. Department of Obstetrics and Gynecology, University College London (H.H.G.M., M.A.H.), London, United Kingdom WC1E 6HX
3. The Physiological Laboratory, University of Cambridge (D.A.G.), Cambridge, United Kingdom CB2 3EG