[1] Digestive Diseases Branch, NIDDK, National Institutes of Health, Bethesda, MD 20892, United States
[2] Departamento de Fisiología, Universidad de Extremadura, Cáceres 10071, Spain
[3] NIH/NIDDK/DDB, MSC 1804, 10 Center Dr., Bethesda, MD 20892-1804, United States