Molecular and Cellular Radiobiology Effeccs of Radiation and Chemicals on Control of Project Title: Hemopoiesis RX-03-02-(b) 14, Scope: (Cont'd.) ratio of mitotic figures and DNA labeling at the different levels of maturation from myeloblast through the myelocyte. These studies are performed before and after the induction of severe inflammation in order to derive insight into the mechanism by which the organism increases the production of granulocytes upon demand. In vivo studies in animals and man are complemented by studies involving the growth of human and animal bone marrow and peripheral blood cells in diffusion chambers implanted into the peritoneum of the mouse in a xenogenic system. An autologous system has been developed in the goat whereby the goat's own peripheral blood or marrow cells are grown in multiple diffusion chambers implanted in its own peritoneal cavity. The growth curves for proliferating and non-proliferating granulo- cytes From normal bone marrow and from peripheral blood cells are measured in terms of the total cell numbers and the rate of progression through the proliferative and differentiated stages of granulopoiesis. Bone marrow and peripheral blood cells from patients with a wide range of hematopoietic disorders are cultured before, during, and after therapy to gain an insight into the disease state. Bone marrow transplantation may be life saving after fatal irradiation or after aplasia induced by drugs, To date, allogeneic transplantation of marrow though partly successful, carries the risk of severe and sometimes fatal graft vs. host disease because of a lack of histocompatability between donor and recipient. The only safe and really effective transplantation is between identical twins, identical, Since the CFUs and the HSC are believed to be reported observations here of an increase in CFUg grown in diffusion chambers, suggests that one might be able to grow useful amounts of HSC's that could be frozen and stored for later use, replication of HSC's will be attempted. | Development of culture The regulation of platelet production and the preparation and pre- servation of platelets for transfusion remain important for treatment of radiation casualties, Inhibitors and stimulators of platelet production are studied when time and facilities permit. Radiation hemorrhage correctable by transfusion of compatible homologous platelets remains impractical because of inadequate preservation techniques, At the Blood Research Laboratory, United States Naval Hospital, Chelsea, Massachusetts, Dr. Valeri is studying the viability and preservation of platelets using normal volunteers. Platelets are prepared, preserved with various tech, and are transfused into individuals prior to administration of niq asp Bm, and their viability studied by determining whether the increased ble time induced by the aspirin is shortened by the autotransfusion of the preserved platelets. The ultimate test of platelet viability and function is the prevention or treatment of thrombopenic bleeding. Colla- borative studies at BNL have been planned on in vivo studies of the hemorrhagic state in animals to correlate the output of red cells in the cannulated thoracic duct with thrombopenia and che decreased output of red cells after transfusion of preserved platelets. (See Continuation Sheet) 1171928) RX-227