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December 27, 1952


JAMA. 1952;150(17):1673. doi:10.1001/jama.1952.03680170027009

It is now well established that lead shielding of various organs or portions of the body increases the survival rate in animals exposed to high doses of x-radiation. While it has been assumed that the beneficial effects are due to protection of hematopoietic tissue, Storer, Lushbaugh, and Furchner1 point out that it has not been shown conclusively that other tissues, such as muscle, connective tissue, primitive reticulum, and bone, which are unavoidably shielded in these experiments, do not contribute to the protective effect or that this protection depends on well-developed hematopoietic tissue. The Los Alamos investigators have offered an answer to these uncertainties by an ingenious series of experiments that took advantage of the fact that the marrow cavity of the rat tail, which normally contains only fat and reticulum, becomes gradually filled with hematopoietic tissue if the tail is implanted in the abdominal cavity.2 Ectopic marrow was