1. Division of Endocrinology, Diabetes and Metabolism, University of South Carolina School of Medicine, Columbia, South Carolina.
2. Biomedical Department of Internal Medicine and Medical Specialties, University of Palermo, Palermo, Italy.
3. Department of Physiology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt.
4. Department of Internal Medicine, Division of Endocrinology, University of Texas Medical Branch, Galveston, Texas.
5. Euro-Mediterranean Institute of Science and Technology, Palermo, Italy.