[Experimental studies on the elimination of minimal residual leukemia in vivo by alternate half body irradiation].
The purpose of this study is to develop a new way for leukemia patients to tolerate an ablative chemoradiotherapy without BMT. Previous studies had demonstrated that only a few leukemia cells remained in the body during remission phase following chemotherapy and did not migrate to distant organs via the circulation until they had given rise to 3-4 x 10(5) new cells. The period required for such growth was about 20 days. However, hematopoietic stem cells migrate earlier than do leukemia cells. Therefore, alternate half body irradiation (HBI) within this period would kill the residual leukemia cells, but hematopoietic stem cells would migrate from shielded marrow to irradiated marrow and reconstruct hematopoiesis. BN rats were injected i.v. with 10 BNML subline LT12nl #15 cells, which had been transfected with the E. coli Lac-Z and Neo genes by retrovirus-mediated gene transfer. Cytochemical X-gal staining was used to identify the leukemia cells in agar culture. At day 9 after inoculation of leukemia cells, the rats were treated with cyclophosphamide (Cy 120 mg/kg), and 3 days later irradiated with 10 Gy (2 Gy/min, 6 MV, X-rays) on the upper half body, with the lower body shielded by a lead brick. They were then irradiated with the same dosage in the lower body with the upper half body shielded a week later. The preliminary results were as follow: At day 9 after inoculation, the cellularity of bone marrow (humerus, sternum, femur and tibia) was in the normal range, and the number of L-CFU ranged from 3.6 x 10(-5) to 9.0 x 10(-5) in agar culture.(ABSTRACT TRUNCATED AT 250 WORDS)
Chu
J
J
Institute of Hematology, Tianjin.
D000818:Animals; D003131:Combined Modality Therapy; D003520:Cyclophosphamide / Q000627:therapeutic use; D015470:Leukemia, Myeloid, Acute / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D009368:Neoplasm Transplantation; D051381:Rats; D011914:Rats, Inbred BN; D014407:Tumor Cells, Cultured; D014410:Tumor Stem Cell Assay; D014916:Whole-Body Irradiation / Q000379:methods*
D003520:Cyclophosphamide