1. Vitamins and Carcinogenesis Laboratory, Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, MA
2. Vitamin Metabolism Laboratory, Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, MA
3. Department of Clinical and Experimental Medicine, Policlinico G.B. Rossi, University of Verona, Verona, Italy
4. Mass Spectrometry Laboratory, Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, MA
5. School of Pharmacy, University at Buffalo, Buffalo, NY
6. Comparative Biology Unit, Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, MA
7. Divisions of Clinical Nutrition and Gastroenterology, Tufts University School of Medicine, Boston, MA