1. Puebla Research Coordination, Instituto Mexicano del Seguro Social, CP 72000 Puebla-PUE, Mexico
2. School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7080, USA
3. Hospital General Regional Número 36, Instituto Mexicano del Seguro Social, CP 72090 Puebla-PUE, Mexico
4. Laboratory of Liver, Pancreas and Motility (HIPAM), Department of Experimental Medicine, Faculty of Medicine, Hospital General de México, Universidad Nacional Autónoma de México (UNAM), CP 06726 Mexico City, Mexico