1. Joslin Research Laboratory, Department of Medicine, Peter Bent Brigham Hospital, Harvard Medical School, Boston, Massachusetts 02215
2. Division of Biology and Medical Sciences, Brown University, Providence, Rhode Island 02912
3. Department of Surgery, Peter Bent Brigham Hospital, Harvard Medical School
4. Department of Pathology, University of Massachusetts Medical School, Worcester 01605
5. Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge 02138
6. Amicon Corporation, Lexington, Massachusetts 02176