Donald G. Walker (1925–1979), Professor of Anatomy, School of Medicine, Johns Hopkins University, made the epochal discovery that a congenital systemic orthopedic disorder is reversible. His discovery that osteopetrosis in the gray-lethal mouse could be cured by temporary parabiosis was immediately followed by clinical trials of transfusions of normal bone marrow cells into children with Marble-bones disease. The validity of Walker's work has been established by reports of successful treatment by pediatric clinics all over the world. Walker also demonstrated that not only could osteopetrosis be cured by bone marrow cell infusions, but the disorder could be induced in normal mice by irradiation and transfusion of spleen cells of micropathalmic mice. One unhappy occurrence in Walker's career was a misguided peer review that disapproved his application for a competing renewal grant application. Walker was the model of a great teacher of anatomy. He was a quiet, soft spoken, kindly person. Colleagues greatly admired his painstaking application of the scientific method to clinical medicine. By his application of Koch postulates to a congenital disorder, Walker proved that the difference between basic and applied research was insignificant. In 1973, he received the Nicolas Andry Award by the Association of Bone and Joint Surgeons. As shown in the photograph below (Fig. 1), he was the first professor in Johns Hopkins history to be chosen by medical students for excellence in teaching.
MARSHALL R. URIST, M.D.
The excessive accumulations of spongiosa in the long bones of congenitally osteopetrotic mice permanently disappeared after a brief parabiotic union to normal littermates. Most of the bone removal was accomplished long after interruption of parabiosis. It is proposed that, during parabiosis, progenitors of competent osteolytic cells were recruited from the blood of the normal mouse.
Professor of Anatomy, Department of Anatomy, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205.
Reprinted with permission from: Walker, D. G.: Osteopetrosis cured by temporary parabolis. Science 180:875, 25 May 1973. Copyright 1973 by the American Association for the Advancement of Science.