Chromosome aberrations in patients treated with telecobalt therapy for glioblastoma.

The yield of dicentric chromosomes has been recorded in peripheral blood lymphocytes of patients undergoing telecobalt therapy for glioblastoma. Blood samples were taken by venipuncture, prior to the first radiotherapy session and 24 h after 10, 20 and 30 Gy to the tumor volume. On the basis of the maximum likelihood method, the yield of chromosome aberrations was best fitted by a linear quadratic dose-response relationship. According to this relationship, the dose inducing ten dicentrics at the target volume is 58 Gy, a value considerably higher than those found after radiotherapy for mammary carcinoma (15 Gy) or for pelvic tumors (5.62 Gy). Our results indicate that, in the case of fractionated exposures, confined to a small volume of the body, it is not possible to estimate the total dose administered and that the method only provides an estimate of the proportion of the lymphocytes irradiated

[Kinetics of the propagation of a murine virus (C57Bl mice) in the lymphoid system and bone marrow of rats (study using electron microscopy)].

Either a Slow (SL) or Early (EL) type of leukemia are respectively induced in rats by the RadLV-Rs derived BL/F (SL) and BL/F (EL) viral populations. The kinetics of virus propagation was studied comparatively in the thymus, spleen, lymph nodes and bone marrow of rats infected either with BL/F (EL) or BL/F (SL). During the first days after inoculation with BL/F (SL), the viral population increased rapidly in all tissues, reaching a peak at day 8 to 10, except in the lymph nodes which were almost devoid of viral particles. A very different pattern was shown by the EL leukemia, indicating the importance of the early distribution of viruses amongst the lymphoid tissues in view of the further development of the disease. The large amount of viruses observed inside the megakaryocytes and budding from these cells confirm that they play a role in the leukemogenesis