Animal experiments to investigate the toxicity of tumoricide agents

To evaluate bone marrow toxicity, the peripheral blood values of leucocytes and thrombocytes were long-term examined over 7 months under conditions of a mice-whole-body irradiation. The examination covered the following points = 1) Differently fractionated irradiation. 2) Partial body irradiation with exclusive protection of the bone marrow by covering the mouse tail. 3) Synchronous treatment with irradiation and administration of 5-Fluoro-Uracil, resp. the piperazine derivative ICRF 159. It was seen that = a) Bone marrow toxicity is mainly determined by irradiation both acute and medium-term, not depending on the fractionating and without a more significant summation of the toxicity by simultaneous chemotherapy; b) long-term toxicity of exclusive irradiation depends on the fractionating, with an optimization (of minimal effect) after 2 (to 3) irradiations per week, a simultaneous chemotherapy intensifies the fractionating effects of the irradiation, irrespective of its own delayed effects, in a synchronously combined radio-chemotherapy, the depression is mainly to the disadvantage of the chemotherapy (ICRF 159); c) the letality can be considerably reduced by a regionally limited protection of the bone marrow (field limitation of the irradiation-fading out the mouse tail). (orig.) 891 MG/orig. 892 RDG