1. Department of Internal Medicine and Nephrology, Hospital Civil de Culiacán, Culiacán, Mexico
2. Centro de Investigación y Docencia en Ciencias de la Salud, Universidad Autónoma de Sinaloa, Culiacán, Mexico
3. Instituto Mexicano del Seguro Social (IMSS), Mexico
4. Division of Nephrology, Hospital Obrero #2 – C.N.S., Cochabamba, Bolivia
5. Department of Nephrology, Hospital General de México, Mexico City, Mexico