Effects of Irradiation on the Blood and Blood Forming Tissues.

摘要

A review is given of the effects of external whole body and local irradiation in man and experimental animals. Internal irradiation by radioactive substances in man and experimental animals is considered. An abstract of pertinent findings is given in the summary and conclusions. All investigators are in agreement that blood formation occurs embryologically in an identical manner in all mammals. It consists of a condensation in the yolk sac of the embryonic connective tissue, the mesenchyme, into blood islands, the central cells of which 'round' up into basophilic cells which give rise to the primitive erythroblasts. These first basophilic cells have been called large lymphocytes by Maximow, hemocytoblasts by Bloom, Maximow, and by many other names. The blood cells produced in this embryonic site are largely so-called primitive red corpuscles which acquire hemoglobin, remain nucleated, and carry oxygen. As the embryo grows, primitive cells migrate to other sites and they, as well as local mesenchymal cells in these sites give rise to the definitive generation of red corpuscles, granulocytes, megakaryocytes, lymphocytes and other blood cells. The production of the cellular elements of the blood in places other than the yolk sac proceeds in a definite pattern, probably in the following order: liver, spleen, lymph nodes, and bone marrow. No division of function into production of myeloid and lymphatic cells occurs in any of these sites until late in embryonic life.