[en] The study of dose-response relationship by a colorimetric titer (MTT) assay and a clonogenic assay in Hela-S₃ cells irradiated with 8 MeV X-rays under anaerobic and aerobic condition is reported. The experiment curves were drawn based on the model of a single hit multi-target. the results show a closer relationship in the MTT assay than that in the clonogenic assay. The two methods yield similar OER, Dq and n values, but the D₀ value of MTT assay. It suggests that in radiobiological study it is feasible to substitute MTT assay for the traditional clonogenic assay

[en] Objective: In order to detect if any analysis of frequency of micronucleated polychromatic erythrocytes (fMPCE) in mouse bone marrow was possible to diagnose combined radiation-burn injuries. Methods: By using the index of fMPCE, the investigation was carried out in the conditions of burn injury alone, radiation injury alone and combined radiation-burn injury. Results: The fMPCE induced by 10% and 20% body surface area (BSA) burns were not significantly increased at 24h compared with untreated groups. The fMPCE induced by combined radiation-burn injury significantly lower than those by radiation alone, and the fMPCE in the 20% BSA combined radiation-burn injury groups were lower than those in 10% BSA groups. Conclusion: These results indicate that radiation combined burns have an effect to reduce the fMPCE induced by radiation injury. The reason may be due to the frequency of increase of PCE after burn injury

[en] Objectives: Thrombopoietin (TPO) is a normal physiological hematopoietic factor which is able to stimulate the hematopoietic progenitor cells to proliferate and differentiate into megakaryocytes and to induce the production and release of platelets. In this study rhTPO was cloned to be potentially used for treatment of radiation-induced thrombocytopenia, the authors studied the prokaryotic expression of rhTPO. Methods: According to the cDNA sequence encoding hTPO published elsewhere, the authors designed two sets of PCR primers at first, and cloned hTPO gene from fetal liver mRNA by means of RT-PCR, then subcloned it into prokaryotic expression vector pBV220 to form recombinant expression plasmids pBV220/TPO, and to transfer it into prokaryotic cells escherichia coli, DH5α. Expression was induced by heat of 42 degree C. Results: The authors obtained the aimed prokaryotic expression of recombinant (r) hTPO by assessment of SDS-Page. Conclusion: hTPO can be expressed completely in prokaryotic cells. The prokaryotic expression of rhTPO might be a basis for the bio-treatment of radiation induced thrombocytopenia

[en] Objective: To assess the radiosensitization of nitro-triazole derivatives and elucidate the structure-activity relationships within this group of compounds. Method: The partition coefficient (p), reduction potential (E_1/2), cytotoxicity and sensitization activity were determined by HPLC, polarography and colony formation, respectively. Results: It was found that among these 22 derivatives, two compounds were more efficient than MISO, and other three were of the same efficiency as MISO was in radiosensitizing hypoxic cells, the rest showed poor radiosensitizing properties. As 2-nitroimidazoles, the radiosensitizing activity of a 3-nitro-triazole derivative correlates with its electron affinity, determined as E_1/2, half-wave reduction potential. The greater is the electron affinity i.e. the more positive the E_1/2, the greater is the radiosensitizing efficiency. The value of E_1/2, partition coefficient p value and cytotoxicity of a nitro-triazole derivative are influenced by the structure and chemical properties of the substituent at N¹ or 5 position of triazole ring. The nitro-triazoles examined show only limited differential hypoxic: aerobic toxicity. Conclusion: Although the nitro-triazole derivation are not viable hypoxia-mediated cytotoxins, the radiosensitization of some of them should be studied thoroughly

[en] Objective: To design an ambient dose equivalent dosimeter with digital display for radiation protection, which is based on the definition of the new operational radiation quantity for environmental monitoring-ambient dose equivalent recommended by the International Commission on Radiation Units and Measurements (ICRU) Report 39. Methods: Considering the energy response of the instrument, the inner wall of ionizing chamber is coated with gum graphite added with a bit of metal powder. Results: Using this chamber, measurement of H^*(10) for photon radiation with unknown spectrum distribution is possible in the energy range from 47 keV to 230 keV with an uncertainty of better than 5%. The configuration, technology and dosimetric performance of the chamber and automatic functions of the reader are presented. Conclusion: The ambient dose equivalent dosimeter can be used as not only a working reference dosimeter, but also a field dosimeter for radiation protection because the readings are expressed directly in ambient dose equivalent and averaged automatically in the period of measurement. Also, its power is supplied by battery for the portable purpose and the readings are displayed on the screen with light-background for dim field

[en] From Nov. 1988 to Mar. 1993, cooperated by China and Japan, a survey of outdoor and indoor ²²²Rn concentrations in 10 cities which were highly populated in China was carried out by means of passive method. the annual mean of outdoor ²²²Rn concentration in 10 cities was 8.8 Bq·m^-3. The highest of 13.5 Bq·m^-3 was in Wuhan, the lowest of 3.3 Bq·m^-3 was in Chongming Island of Shanghai; and there were no significant differences among the different years in the same areas. During the northwest wind seasons, about 50% of outdoor ²²²Rn concentration in Taiwan was contributed by the airflow from the mainland. Typical apartment houses and offices built of brick and concrete were also surveyed for indoor ²²²Rn concentration. The annual mean of indoor ²²²Rn concentration in the 10 cities was 19.5 Bq·m^-3. The highest of 33.9 Bq·m^-3 was observed in Guiyang, the lowest of 9.0 Bq·m^-3 was observed in Chongming Island of Shanghai. The outdoor and indoor ²²²Rn concentrations showed a clear seasonal pattern with the minimum in summer and the maximum in winter. And they also showed a clear geographic distribution tendency; they were higher in inland than in seashores, and higher in the south than in the north. The ratios of indoor to outdoor ²²²Rn concentrations were from 1.1 to 4.6. The annual effective dose equivalents resulting from outdoor and indoor ²²²Rn concentrations amounted to about 0.64 mSv·a^-1. The highest was in Guiyang, and the lowest was in Nantong, being 1.12 and 0.39 mSv·a^-1, respectively

[en] An image processing solid state nuclear detector (SSNTD) for radon survey has been developed by using computer technique of image discrimination. The method had good accuracy, i.e., the Rn concentration (106.8 +- 3.4 kBq·m^-3·h), by this detector was in good accordance with the given exposure value (115.6 +- 3.4 kBq ·m^-3·h), and greatly increased measurement speed. It has been widely used in Rn investigation in hundreds of dwellings and galleries

[en] The authors present the clinical effect and chromosome damage sustained by a fetus and the four months pregnant mother in an accidental ⁶⁰Co exposure in November of 1992 in Xinzhou, Shanxi Province. The mother suffered from a moderate acute radiation sickness with ratardation of fetal development. After delivery, the infant's body length, body weight and head circumference were all lowered by three percentiles compared with the normals. Four months after the exposure, the assay of the mother's peripheral lymphocytes showed a chromosome aberration rate of 36%, while concomitant examination of the baby failed to reveal any chromosome abnormality although the sister chromatid exchange rate was remarkably higher than that of the mother and the normal control

[en] In experiments, adaptive response was found by using cytokinesis block micronucleus method. The experiments were carried out in human lymphocytes from four donors. The cells were previously exposed to low concentrations of ³H-TdR at 3.7·10² Bq/ml and 1.48·10² Bq/ml, and subsequently were challenged with high dose of ³H-TdR (3.7·10⁴ Bq/ml) or 1.5 Gy of ⁶⁰Co γ-rays. The results showed that low dose exposure could cause adaption and lead to a reduction in the number of micronuclei induced by the challenging dose. It indicated that an adaptive response was observed in human lymphocytes and there were variations among individuals. It was also found that the adaptive response could be eliminated by adding 3-AB

[en] Changes in contents of the two kinds of neuropeptides have been measured in the brains of postnatal G57BL/6J strain mice that received accumulative doses of 0, 0.05, 0.10 or 0.30 Gy respectively in utero from tritium β-irradiation during the mother mice's pregnancy from the 12.5th day of gestation to the day of delivery. Dose response relationship for alteration in somatostatin content due to exposure to 0.10 Gy or above was observed, and it was also noted that 0.30 Gy could cause decrease in arginine vasopressin in hypothalamus. These results were consistent with findings in research on brain development and reflex behavior in the literature. 0.10 Gy exposure may represent a threshold for exposure to tritiated water within the range from day 12.5 of gestation to the day of delivery using change in content of somatostatin in hypophysis as a parameter