ヒトだ液せんがん由来ヌードマウス可移植性しゅようの樹立とその放射線感受性に関する細胞動態学的研究

Abstract

The present study was performed for elucidation of the biologicalproperties of the transplantable tumor in nude mice and objective evaluation of X-irradiation effects through its cell kinetics. The experimental results are as follows:1. An undifferentiated carcinoma arising in the palatal gland of a 69-year-old woman was inoculated into BALB/c-nu/nu nude mice, and the transplantable tumor, TS-1, has been established.2. The histology of TS-1 tumor was almost identical to that of the original tumor through the serial passages.3. The following cell kinetic parameters of TS-1 tumor were obtained:doubling time (TD): 33 days, time of cell cycle (Tc): 52.4 hours, DNA synthetic time (Ts): 12.8 hours, growth fraction (GF): 63.0%, and cell loss factor (CL): 89.4%4. The growth rate of TS-1 tumor was approximately the same as that of the metastatic foci of the original tumor in the patient's lung, indicating the maintenance of original properties of the transplantable tumor.5. The cell death caused by single dose irradiation with 1, 000rad was suggested mainly to be a “reproductive death”, whereas the death by single dose irradiation with 3, 000, 5, 000 rad, and 5 fractionated dose irradiation with 1, 000 rad was considered largely to be an “interphase death”.6. The possibility of proliferating tumor cells to reutilize 3H-TdR liberated from the dead cells after single dose irradiation with 3, 000, 5, 000 rad and 5 fractionated dose with 1, 000 rad was speculated.7. The GF value of the 3rd day of irradiation became lower in correlation with an increase of the irradiation doses. Single dose irradiation with 1, 000 rad prolonged Ts and Tc, while that with 3, 000 rad slightly prolonged Ts but shortened Tc. Single dose irradiation with 5, 000 rad and 5 fractionated dose irradiation with 1, 000 rad apparently shortened both the Ts and Tc values.8. Comparing the single dose irradiation with 5, 000 rad and the 5 fractionated dose irradiation with 1, 000 rad, a dominating aspect of the fractionated method was indicated as judged by its increased effective inhibition of tumor proliferation and decreased cutaneous damage.