1. Consorci Sanitari del Garraf, Servicio de Nefrología, Barcelona, Spain
2. Advanced Unit of Renal Sonographic Diagnostics, Puerto Ordaz Clinic, Puerto Ordaz City, Venezuela
3. Universidad Simon Bolívar Facultad de Ciencias de la Salud, Barranquilla, Colombia
4. Department of Physiological Sciences, Universidad de Oriente, Bolívar, Venezuela
5. Rutgers, The State University of New Jersey, New Brunswick, NJ, USA