[en] Radiosensitivity of spleen CFU depositing in bone marrow and in the spleen does not differ essentially. For CFU forming colonies in the spleen the Dsub(o) value varies within 105-120 R. For CFU forming colonies in bone marrow the value of Dsub(o) is 120-135 0. It is suggested that in bone marrow there are 2 fractions of CFU one of which is radiosensitive and the other radioresistant. It is mainly radiosensitive fraction of CFU that is localized, in the spleen

[en] Kinetics and radiosensitivity of human lymphocytes were studied by the techniques of monolayer agar culture and liquid culture in vitro. In the experiments of lymphocyte kinetics, PHA was designated as a motogen for T lymphocyte. LPS, MEBC and BSA were chosen as mitogens for B lymphocyte. The data from thses experiments showed that under the alone or combination stimulation of LPS, MRBC and BSA, B lymphocytes developed to form colonies in agar culture (0.3%) with the same manner. The stimulation of LPS to B lymphocytes was most significant. By the day 6 after seeding, the numbers of colonies in agar culture were maximal. Whereas the numbers decreased significantly by the day 8. The number of T lymphocyte colonies increased with culture time within 12 days. The peak of ³H-TdR incorporation into T lymphocytes in liquid culture occured at 5th day after seeding. The data above-mentioned demonstrated that the kinetics of lymphocytes cultured in two kinds of environments were different. The studies of the radiosensitivity of T lymphocytes showed that the decreasing in the number of colonies and rate of ³H-TdR incorporation varied in different dose ranges. In the range of 0∼1.0 Gy, r = -0.96, D₀ value was 1.71 Gy for TL-CFC in agar culture, r = -.96, D₀ value was 4.34 Gy for the proliferation T lymphocytes in liquid culture. In the range of 1.0∼6.0 Gy, r were -0.99 and -0.98, the D₀ were 5.88 and 7.36 Gy respectively. The declining tendency in colonies formed by BL-CFC was the same as that of TL-CFC, r = -0.97, for the range of 0∼1.0 Gy, r = -0.97, for the range of 1.0∼3.0, the D₀ values were 1.35 and 4.36 Gy respectively. The results from these experiments shown that the colony technique was a good method for the study in radiosensitivity

[en] To determine radiation survival curves for mammalian cells cultured in vitro it is standard practice to irradiate the cells in microcolonies after a period of attachment. A method is proposed to determine the average multiplicity of viable cells, the parameter needed to convert microcolony surviving fraction to single cell surviving fraction. If the fractions of cells able to grow into macrocolonies (plating efficiency) and of those able to attach (attachment efficiency) are known, the average viable cell multiplicity corresponding to a given average cellular multiplicity can be estimated with good accuracy. In cell lines with plating efficiency significantly lower than attachment efficiency, substitution of viable cell multiplicity for average cell multiplicity may help to avoid errors in the interpretation of survival data

No abstract available

[en] The radiosensitivity of human stem cells is discussed. New techniques for the study of stem cell radiosensitivity are described

[en] Radiation survival of MOLT-4, a leukaemic T-lymphocyte cell line, was measured by counting colonies formed in 0.8% methyl cellulose. The survival curve was a simple exponential and showed the cells to be radiation sensitive, with D₀=0.49+-0.02 Gy and extrapolation number n=0.92+-0.09. No increase in survival as measured by colony-forming ability or trypan blue dye exclusion was seen when the dose was split into two fractions, separated by a 5 h incubation period. Electron microscopy and trypan blue dye exclusion showed that 5 h after exposure to high doses, MOLT-4 cells began to die and displayed condensed, marginated chromatin and cellular vesticulation. (author)

[en] The results of the microbiological surveillance of workshops in seven factories are repoted. The data obtained showed that the use of the general sterile measures are the better methods for microbiological surveillance. The microbes in the environment can be controlled at the permitted number (≤ 500 CFU/m³) and the high standard of the biological load (≤ 1 CFU/m³) in medical instruments is ensured. The resistance among the common micro-organisms has not been found. This can provide a scientific basis for selecting the dosage of irradiation and safe clinical use

[en] Spleen colony-forming stem cells of the bone marrow of mice (CFU) have been used as an in vivo test system for toxic and radiosensitizing effects of misonidazole. The cells were irradiated in vivo in the donors before they were suspended and injected i.v. into recipients. Hypoxic conditions were achieved by killing the donors 20 min before irradiation. A drug dose in donors of 1.0 mg/g body wt (ca 1200μg/ml in serum) was found to be weakly toxic over an exposure time of 50 min under hypoxic conditions. The radiosensitizing effect at this concentration was found to be about the same as the full effect of oxygen. (author)

[en] The previously reported decrease in the ratio of erythrocytic (E): granulocytic (G) spleen colonies observed 8 days after bone marrow transplantation, when the donors had been x-irradiated up to 4 hours before the marrow was taken for transfer, was confirmed. The effect of taking the marrow between 4 hours and 13 days after x-irradiation, on the E:G ratio in both spleen and femoral bone marrow colonies, has been studied in detail. The reversion to a normal E:G ratio in spleen colonies assessed at 8 or 10 days was associated with increases in this ratio of colonies in the femoral bone marrow. Transplantation of cell suspensions prepared from the spleen and femoral bone marrow of primary recipients 8 days after the initial transfer produced a histological distribution of 8-day colonies in secondary recipients which was independent of x-irradiation of the donor. The data suggest that a hypothesis involving CFU migration within the spleen and, possibly, from the bone marrow to the spleen, provides a more satisfactory explanation of the data than one involving two CFU populations with different radiosensitivities. (author)

[en] The bone marrow stromal cells have been implicated as an integral part of the haemopoietic microenvironment, which is responsible for the in vivo regulation of adult haemopoiesis Stromal stem cells give rise to adherent colonies of fibroblast-like cells in vitro. This CFU-F assay allows the study of functional characteristics and qualitative and quantitative responses of the stromal cells. Experiments to determine CFU-F concentrations in femoral bone marrow pooled from 3 to 8 normal adult mice gave results which were not reproducible. From one experiment to another, the mean CFU-F concentrations varied from 0.5 to 4 CFU-F 10^-5 bone marrow cells even though all the experiments were performed with identical culture conditions according to a standard procedure for CFU-F assay. In this study the authors found that the variability was due to important individual variations in the concentration of CFU-F between different animals (mice). (author)