1 Institute for Diabetes, Obesity, and Metabolism, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104.
2 Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104.
3 Institute for Diabetes, Obesity, and Metabolism, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104; lazar@pennmedicine.upenn.edu.