[en] The frequencies of micronuclei, micro-nucleate cell and various micro-nucleate cell in human lymphocytes, which had been irradiated with ⁶⁰Co gamma ray at different doses and dose rates, were investigated after 72 hours of irradiation. The results are as following: (1) the relationship between dose and frequency of micronuclei of frequency of micro-nucleate cell is a quadratic polynomial, and at high dose the exponential correction is needed. (2) The uncertainty of estimated dose by dose-effect curve is depending on the dose rate, especially, in the low dose range the influence is remarkable. (3) By using of different thresholds of dose and dose rate for appearing micro-nucleate cell, the dose and dose rate received by human body can be roughly estimated and the uncertainty can be reduced

[en] Objective: To study the induction of DNA double-strand breaks (DSBs) in human osteosarcoma cells irradiated by X-ray, the DNA DSBs repair process and the tumour cell radiosensitivity. Methods: Two cell lines of human osteosarcoma, Rho0 and 143. B were used. Initial DNA damage of DSBs by X-ray irradiation was measured using clamped homogeneous electrical field (CHEF) electrophoresis. Results: X-ray-induced DNA DSBs of human osteosarcoma cells after CHEF-electrophoresis increased linearly with the irradiation dose between 0 and 50 Gy. The repair of DNA DSBs in human osteosarcoma cells increased with the post-irradiation incubation time. In contrast to 14.3B cell line at the same dose point, much more DNA DSBs were induced in Rho0 cell line after X-ray irradiation. Conclusion: CHEF pulsed-field gel electrophoresis (PEGE) is a sensitive method for the determination of radiation-induced DNA DSBs in high molecular weight DNA of human osteosarcoma cells. Radiation-induced DNA DSBs of osteosarcoma increase with the dose in a linear manner. After incubation, both Rho0 cell line and 143. B cell line can repair the DNA DSBs. Between two cell lines of human osteosarcoma, Rho0 and 143.B, Rho0 cell line is more sensitive to ionizing radiation than 143.B line

[en] Calyculin A was added into the human blood samples irradiated by ⁶⁰Co γ-ray at different doses (0, 0.25, 0.5, 1.0, 2.0, 3.0 Gy) after 46 h irradiation. Chromosome condensations induced by Calyculin A were observed and compared with conventional chromosome aberrations. The results showed that the mitotic index of PCC induced by Calyculin A was much higher than those obtained with conventional colchicine block or G₀-PCC by fusion; and there was a linear relation between the fragments of PCC induced by Calyculin A and the dose

[en] The results of concentration measuring of ²²²Ru and its daughters and estimation of internal doses to workers in the underground buildings at Nanjing city are presented. The double filtering membrane method and Thomas method were used in the monitoring of ²²²Rn and its daughters, and the dose conversion factor was taken from the latest UNSCEAR report. Concentration distributions of ²²²Rn and its daughters were approximately log-normal. The geometric means for ²²²Rn was 40.5 Bq · m^-3 and for its daughters was 1.4 x 10^-7 J · m^-3. The equilibrium factor was 0.63. The radioactive equilibrium ratio between short-lived ²²²Rn daughters was 1:0.57:0.49. The estimation value of annual effective dose equivalent from ²²²Rn daughters to workers working at underground sites was 1.3 mSv, which was 86% higher than that of those working on ground sites

[en] Ataxia Telangiectasia (AT) as a genetic disorder results from single gene mutation, characterized by radiosensitivity, progressive nerve degeneration, immunodeficiency, premature aging and cancer predisposition. Progress in the research of AT is reviewed in this paper, including the clinical symptoms of this disorder, as well as the localization, structure and function of ATM (AT mutated) gene, the effects of ionizing radiation on the signal transduction of AT cells, AT genomic instability and AT gene therapy

[en] It has been proved that the antimalarial agent, Artemisinin and its derivates (such as artemether, arteether, artesunate, dihydroartemisinine, etc) boast powerful antitumor effects. Recently, researches have found that Artemisinin and its derivates can also enhance the radio-sensitivity of tumors through regulating cell cycle, creating cytotoxic effects induced by ROS, suppressing GSH activity and inhibiting the reparation of DNA damage etc. Moreover, they can reduce cell survival in a dose-dependent manner. This paper is paying more attention on the radio-sensitizing effects, characteristics and mechanisms of artemisinin and its derivates. (authors)

[en] Objective: To observe the changes of cell cycle on cancer cells after dihydroartemisinin and X-ray irradiation. Methods: Human HeLa cells of cervical cancer with p53 mutation was used and human SiHa cells of cervical cancer with wild p53 was used as control. Flow cytometry was used to detect the effect of dihydroartemisinin (20 and 100 μmol/L) and irradiation (6 Gy)on cell cycle. Western blot was used to measure the levels of cell cycle protein. Results: G₂ arrest was observed in irradiated HeLa cells, which the proportion of cells in G₂ phase was increased from 14.45% to 73.58% after 6 Gy X-ray irradiation, but it was abrogated by dihydroartemisinin from 73. 58% to 48.31% in HeLa cells, and it had no change on the SiHa cells. The elevated Wee1 protein and the lowered Cyclin B1 protein were observed with the G₂ arrest severity. The expression of radiation-induced Wee1 protein was suppressed and the Cyclin B1 protein was increased after dihydroartemisinin treatment, which was in accordance with the abrogation of radiation-induced G₂ delay. Conclusions: The main effect of irradiation on cell cycle of p53 mutated HeLa cells is G₂ arrest. Dihydroartemisinin could abrogate it, which is associated with the changes of Wee1 protein and Cyclin B1 protein. In Siha cells, the main effect of irradiation on cell cycle is G₁ arrest, and dihydroartemisinin has no effect on it. (authors)

[en] Objective: To explore the feasibility of using fluorescence in situ hybridization (FISH) to detect stable chromosome translocation as a biological dosimeter. Methods: Translocation and dicentric frequencies in peripheral blood lymphocytes induced by ⁶⁰Co γ-rays at different doses were analysed by conventional staining and dual-colour FISH with composite whole chromosome-specific probes for human chromosomes 1 and 4, and their dose-response curves were fitted. Results: All dose response curves for translocation and dicentrics from FISH analysis, as well as dicentrics from conventional staining could be described by linear-quadratic equations Y = c + αD + βD². The difference between dicentric frequencies analysed by FISH and conventional staining were not statistically significant (P>0.05). for radiation-induced translocation and dicentrics in chromosomes 1 and 4, no significant differences were found between the observed frequencies and expected frequencies based on DNA content. Conclusion: Chromosome translocation can be quickly and accurately analysed by FISH and has a good dose-response relationship; thus, it is hopeful to use translocation frequencies measured by FISH as a long-term or accumulative biological dosimeter

[en] To investigate the effect of artesunate on radio-sensitivity of human cervical cancer cells in vitro. The human cervical cancer cells HeLa and Siha were used as the experimental cells. MTT assay was used to determine the most appropriate drug concentration in the subsequent experiment, and the effect of human cervical cancer cells treated with artesunate and irradiation of ⁶⁰Co γ-rays was studied by using conventional chromosomal aberration analysis and cytokinesis block method (CB method). The results show that when the concentration of artesunate in this experiment was 2.0 μmol/L for HeLa cell and 4.0 μmol/L for Siha cell respectively, the chromosome aberration, micronuclei cell and micronuclei rates of HeLa cells treated with artesunate were more serious than that of the only irradiation, but there is almost no change with Siha cells. (authors)

[en] Poly (ADP-ribose) polymerases (PARP) constitute a family of enzymes involved in the regulation of many cellular processes. It plays a vital role in many physical and physiopathological processes,, In the past ten years scientists have conducted extensive research on PARP and its inhibitors, among which the role of PARP inhihitors in radiosensitization, chemopotentiation and neuroprotection have been placed close attention. There have been several PARP inhibitors entering the clinical trials, which predicts its sound application perspectives. (authors)