1. Department of Internal Medicine, San Juan Bautista Medical Center, P.O. Box 4964, Caguas, PR 00726-4964, USA
2. Endocrinology Section, San Juan City Hospital, San Juan, PR, USA
3. San Juan Bautista School of Medicine, Caguas, PR, USA
4. Neurosurgery Department, School of Medicine, University of Puerto Rico, San Juan, PR, USA