最新刊期
      期 3 ， 2004
      • ZHANG Lihua,DU Na
        Vol. 22, Issue 3, Pages: 129-138(2004)
        摘要：In an attempt to explore the effects of structure and mobility multiplicity of polymers on the mechanism of radiation crosslinking, the adaptability of Charlesby-Pinner’s equation and its various modified versions are examined. In the present paper, the effects of chain structure and state of aggregation on radiation crosslinking of polyethylene, polyethylene oxide and polyamides were studied with emphasis on the roles played by end groups, chain branches, and morphological factors. The experimental data of other polymers reported in the literature are also gathered and carefully analyzed. It is indicated that both chemical and morphological multiplicity of polymer structure result in the multiplicity of crosslinking mechanism, and which it is main reason of deviation between experimental date and those predicted by the Chharlesby-Pinner’s equation. The deviation at lower doses is closely associated with the structure and content of end groups of the polymer. In this stage, radiation crosslinking reaction takes place non-randomly. With the increase in radiation dose and the gradual consumption of end groups, the effect of end groups tends to become ignorable. Then the crosslinking reaction proceeds randomly, and the experimental date on this stage conform to the Chalesby-Pinner equation perfectly. Random crosslinking of main chain units is the characteristic reaction of amorphous phase only. When the radiation dose further increases, crosslinking takes place nonrandomly, since the Crosslinking reaction in interface of crystalline and amorphous phases.  
        关键词：Radiation effects;Radiation crosslinking mechanism;Structure;mobility of polymer   
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        发布时间：2023-03-30
      • ZHANG Fengying,HOU Zhengchi,YU Ming,XIE Leidong,LI Jing
        Vol. 22, Issue 3, Pages: 139-142(2004)
        摘要：PE films were grafted with 2-hydroxypropyl acrylate by γ−rays, and were placed in supersaturated calcium bicarbonate solution added with PAA. Biomimetic heterogeneous nucleation and growth of calcium carbonate crystals was observed on the PE film template under room temperatures . The samples were characterized by FT−IR, SEM and XRD. The obtained crystals proved to be calcite. The results indicate that in addition to polymer surface structure and proper additives, temperature variation is another key factor for heterogeneous nucleation and growth of calcium carbonate crystals.  
        关键词：γ−radiation;Heterogeneous;Organic crystal;Biomineralization;Composite   
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        发布时间：2023-03-30
      • ZU Jianhua,WU Minghong,QIU Shilong,YAO Side,YE Yin
        Vol. 22, Issue 3, Pages: 143-147(2004)
        摘要：Strong acid cation-exchange membranes were obtained by irradiation grafting of acrylic acid (AA) and sodium styrene sulfonate (SSS) onto high-density polyethylene (HDPE). Thermal and chemical stability of the cation-exchange membranes was investigated. The effectiveness of sulfonate-containing films was conformed in inducing high resistance to oxidative degradation. Thermal stability of the grafted HDPE was weaker than HDPE as detected by TGA analyzing technique. Char residue by TGA of the grafted HDPE is greater than that of HDPE. It shows that the branch chains including –SO3Na and –COOH was grafted onto the backbone of HDPE, and thus give a catalytical impetus to the charring. Crystallinity of the grafted membranes decreased with increasing grafting yield of the membrane samples. Is is supposed that the decreased crystallinity is due to collective effects of the inherent crystallinity dilution by the amorphous grafted chains and disruption of spherulitic crystallites of the HDPE component.  
        关键词：Cation-exchange membranes;Thermal stability;Chemical stability   
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        发布时间：2023-03-30
      • ZHAO Qunfen,LI Yuguo,LIU Ruili,XU Jingying,LI Wenxin
        Vol. 22, Issue 3, Pages: 148-152(2004)
        摘要：Groups of Stylonychia mytilus were exposed to 60Co γ−rays for 1.5h and irradiated to 100, 300, 500, 800, 1200 and 1500Gy, respectively. On the fifth day after the irradiation, surviving fractions of the irradiated groups were about 47%、18%、16%、8%、5% and 3%, respectively, with the increasing the doses. . Based on the observation, radioprotection of fullerenols to Stylonychia mytilus groups exposed to 60Co γ−rays was studied. The results showed that the surviving fractions of the Stylonychia mytilus in fullerenols solutions increased significantly in either the high dose groups and the low dose groups, in comparison to the control group. It was also found that the radioprotection was related to concentration of the fullerenols. The study indicated that fullerenols, as a potential radioprotection medicine, could scavenge free radical and reduce damage of the cells from γ−ray radiation.  
        关键词：Stylonychia mytilus;Fullerenols;γ−rays;Radioprotection;Survival fraction   
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        发布时间：2023-03-30
      • LI Yang,SONG Liangwen,WANG Dewen,PENG Ruiyun,CUI Xuemei,GAO Yabin,JIN Meihong,MA Junjie
        Vol. 22, Issue 3, Pages: 153-156(2004)
        摘要：The work is to investigate expressions and roles of Smad3, Smad4 and Smad7 in pathogenesis of pulmonary fibrosis of rats. Altogether 60 specific-pathogen-free Wistar rats were used in the study, with 50 of them being irradiated with 25Gy 60Co γ−rays on whole thoracic region. The rats were sacrificed and specimens were harvested in 1 day, 1 week, 1month and 3 months after the irradiation. Alveolar macrophages were obtained and cultured. Expressions of Smad3, Smad4 and Smad7 were observed by immunohistochemistry. In normal pulmonary tissue, expressions of Smad3, Smad4 and Smad7 could be seen in the plasma of endothelial cells and smooth muscle cells of blood vessel. Expressions of Smad4 could be seen in the plasma of epithelial cells of bronchi. One day after the irradiation, expressions of the three proteins could be seen in the plasma of some pneumocytes and macrophages. One week and even one month after the irradiation, expressions of Smad4 could be seen in the plasma of some fibroblasts. Three months after the irradiation, expressions of Smad4 could be seen in the nucleus of endothelial cells, macrophages and fibroblasts. The cells, in which Smad3, Smad4 and Smad7 are positive, are main target or effect cells related to the initiation and development of radiation pneumonia and fibrosis. This indicates that Smad signaling might be a key pathway of TGF β−mediated radiation pulmonary injury.  
        关键词：Radiation pneumonia and pulmonary fibrosis;Transforrning growth factor β(TGF β);Smad protein;Signal transduction   
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        发布时间：2023-03-30
      • WANG Yuan,YUAN Xiaoling,ZHAO Zhenhu,SHAN Yajun,CHEN Jiapei,Cong Yuwen
        Vol. 22, Issue 3, Pages: 157-160(2004)
        摘要：To comprehend the feasibility of the inhibitor of tyrosine phosphatase pervanadate using for therapy of radiation injury and inquire into the effects of tyrosine phosphatases on the radiation injury of hematopoietic cells, the effects of different times of administration on NFS-60 cells irradiated with different doses were observed. It was found that pervanadate could specifically enhance the proliferation of irradiated cells, such effects became obvious with the dose of irradiation increased and displayed time effects. For 3Gy irradiated NFS-60 cells, good results were achieved when pervanadate was administrated 24h after irradiation, there were no difference between before and 30 mins after irradiation, but for 5Gy irradiated cells, the best time administration is 24 and 48h after irradiation. Effects of pervanadate administrated before irradiation was better than that administrated 30min after irradiation. These results suggest that protein tyrosine phosphatase might involve in the course of radiation injury of hematopoietic cells. It is hoped that enhancing receptor signal transduction by PTP inhibitors will become a new way of therapy of acute radiation disease.  
        关键词：Pervanadate;Radiation;Proliferation;NFS-60 cells   
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        发布时间：2023-03-30
      • KONG Zhaolu,JIN Yizun,SHEN Zhifen,TONG Sungao
        Vol. 22, Issue 3, Pages: 161-164(2004)
        摘要：The present study aims to analyze the correspondence between intracellular gluthathione (GSH) content and tumour cells sensitivity to γ-rays, to investigate the influence of irradiation on GSH synthesis and to evaluate the feasibility of monitoring patients radiosensitivity by determining GSH in peripheral monocyto. In this experiments, buthionine sulfoximine (BSO), a GSH synthase inhibitor used to adjust intracellular GSH content, was observed its radiosensitization effect in vivo and in vitro. The results indicated that irradiation increased GSH synthese, BSO enhanced cells sensitivity to γ-ray by exhausting intracellulsr GSH, GSH in PMN could be an useful biochemical parameter to monitor patients sensitivity to irradiation.  
        关键词：glutathione;glutathione peroxidase;γ-rays;buthionine sulfoximine;Radiosensitization   
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        发布时间：2023-03-30
      • LIU Yongbiao,LIU Ying,ZHAO Jie,HAO Xingzhi,WANG Xu,YAO Side
        Vol. 22, Issue 3, Pages: 165-170(2004)
        摘要：In this paper the effects of exogenous SOD on differentiation, proliferation, regulation of subpopulation of spleen lymphocytes has been studied with irradiated tumor−bearing mice. The activity of antioxidant enzymes and the contents of redoxic products have also been determined. And the effect of SOD on ultra−structure of spleen of irradiated tumor−bearing mice has been investigated meanwhile the killed effect of spleen tumor under irradiation with addition of SOD has been observed. It has been found that SOD does emphasize the differentiation, proliferation, regulation of subpopulation of spleen lymphocytes cell with radiated tumor−bearing mice and increase the activities of GSH、GPX and total−vigor of SOD while MDA decreased in spleen. It has been also found that SOD injected before or after irradiation can reduce the injury of spleen obviously and makes the tissue have higher protection from irradiation while the tumor was killed as the same as no addition of SOD. It can be deduced that lighten of lipid peroxidation occurs from the scavenge of ROS by SOD, the high protection of sleep from irradiation is because of delay to S phase of lymphocytes and increase of activity of antioxidant enzymes. The concentration change of SOD and ROS may have some influence on signal transferring pathway and gene expression of cell apoptosis.  
        关键词：Superoxide dismutase;Tumor−bearing mice;Subpopulation of lymphocytes;Radiation−protection;Lipid peroxidation   
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        发布时间：2023-03-30
      • LU Ying,YANG Zhihua,CAO Zhenshan,Fan Feiyue,ZHU Maoxiang,Tom K. Hei
        Vol. 22, Issue 3, Pages: 171-175(2004)
        摘要：The work is to investigate α-particle irradiation-induced bystander effects on the mutagenicity in human chromosome 11 in the human−hamster hybrid (AL cells) and its possible mechanism. AL cells were used for assaying mutation rates of human chromosome 11 through screening mutants in the presence of anti−CD59 surface antigen antibody (S1) and complement. A grid was interposed between α−particle source and the cells being irradiated, so as to fix proportion of the irradiated cells (15 %) and the bystander effects on the mutagenicity were detected. Free radical scavenger DMSO and intercellular communication inhibitor Lindane were selected to investigate the potential mechanism of α−particle induced bystander effect. There was clear dose−dependent relationship between mutation rate and the dose of alpha particle radiation. However, the mutant fractions of cell population shielded by the grid in α−particle irradiation system were much higher than the expected levels of irradiated cells. Lindane, but not DMSO, could obviously decrease this bystander effect induced by α−particle irradiation. Alpha−particle irradiation can induce bystander effect on the mutagenicity, in which intercellular communication may play important roles.  
        关键词：Alpha−particle irradiation;Gene mutation;Bystander effect;Reactive oxygen species;Intercellular communication   
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        发布时间：2023-03-30
      • GONG Shouliang,LIU Shuchun,LU Zhe,WANG Zhenqi,LIU Yang,LIU Guangwei,LIU Shuzheng
        Vol. 22, Issue 3, Pages: 176-180(2004)
        摘要：In this paper, dose-, dose rate- and time−effect of adaptive response of thymocyte cycle progression induced by low dose radiation were observed. Kunming mice were irradiated with different inductive doses ( D1) of 25, 50, 100 and 200mGy at a fixed dose rate of 12.5mGy/min, or a fixed inductive dose (D1) of 75mGy with different dose rates of 6.25, 12.5, 25, 50, 100 and 200mGy/min. The mice were then irradiated with different challenging doses ( D2) of 1.0, 1.5 and 2.0Gy at a fixed dose rate of 287mGy/min. The time intervals between D1 and D2 were 3, 6, 12, 24 and 60h. Thymocyte cycle progression was measured with flow cytometer. It has been found that with the mice which had received D1 of 25, 50 and 100mGy at 12.5 mGy/min dose rate and the D2 doses 6h after the D1, or D1 of 75mGy at dose rates of 6.25, 12.5 and 25mGy/min and the D2 doses 3, 6 and 12h after the D1, or D2 of 1.0, 1.5 and 2.0Gy, the percentage ratio of S phase thymocytes decreased significantly (p<0.05 or p<0.01), and the percentage of G0/G1 and G2+M phase thymocytes increased significantly (p<0.05 or p<0.01).too, by comparing the D2 groups to the sham−irradiation group, Comparing the D1+D2 groups to the D2 groups, however, the percentage ratio of S phase thymocytes increased significantly (p<0.05 or p<0.01), and the percentage of G0/G1 and G2+M phase thymocytes decreased in varying degrees. The results suggest that irradiating the mice to 25—100mGy at dose rates of 6.25—25mGy/min 3—12h before exposing them to 1.0—2.0Gy irradiation at 287mGy/min dose rate, the adaptive response of thymocyte cycle progression could be induced under the condition of whole−body irradiation.  
        关键词：Low dose radiation;Cell cycle progression;Adaptive response   
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        发布时间：2023-03-30
      • FENG Huiru,TIAN Jiahe,DING Weimin,ZHANG Jinming,CHEN Yingmao
        Vol. 22, Issue 3, Pages: 181-184(2004)
        摘要：The paoer is to elucidate radiobiological charicateristics and radiobiological mechanism in killing tumor cells with low dose rate β−rays and high dose rate γ-rays. HeLa cells were exposed to low−rate β−irradiation of 32P or high−dose−rate γ−irradiation of 60Co. Cell response−patterns were compared between two the types of radiations in terms of their inhibition of cell proliferation and cell cycle blockage, evaluated by typanblue excluded method and flow cytometry, respectively. Results show that there is a different way in growth inhibition effect on HeLa cells between low−dose−rate irradiation of 32P and high−dose−rate irradiation of 60Coγ. In exposure to 32P, the inhibition of cell proliferation in HeLa cell was a prolong course, whereas and the effect was in a more serious and quick way in 60Co irradiation. Cell cycle arrest in G2 phase induced by 32P was lower and more prolong than that induced by 60Co. The inhibition effect on tumor cells between the two types of radiations is different. Impaired DNA repair system by continuous low−dose−rate radiation might contribute to the final radiation effect of 32P.  
        关键词：low−dose−rate irradiation;High−dose−rate irradiation;Cell−killing effect;HeLa cell line   
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        发布时间：2023-03-30
      • DU Weixia,FU Yinghua,LEI Shujie,LU Xue
        Vol. 22, Issue 3, Pages: 185-188(2004)
        摘要：To compare the sensitivity of chromosome aberrations induced by ionizing radiation between newborns and adults, Cord bloods from newborns and peripheral blood from adults were exposed to 60Co γ−rays under same condition, and then the chromosome aberrations were analyzed by using conventional method. Results: Dicentric frequency in lymphocytes of newborns induced with 2.0Gy and 3.0Gy is about 130% more than those of adults. And the frequencies of acentric aberrations between newborns and adults are almost same; The frequencies of dicentric in lymphocytes from newborns induced by 60Co γ−rays fits linear-quadratic dose-response equation which is described by the formula, y=4.8104D2+5.8314D+0.0034 (r=0.9982). Sensitivity of newborn to ionizing radiation is significantly higher than that of adult.  
        关键词：Radiation sensitivity;Chromosome aberrations;Newborns;Adults;Lymphocytes   
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        发布时间：2023-03-30
      • LEI Suwen,WANG Jufang,SU Xu,ZHAO Jing,LI Wenjian
        Vol. 22, Issue 3, Pages: 189-192(2004)
        摘要：DNA lesions, especially DNA double−strand breaks (dsbs), are looked upon as the dominant molecular effect of radiation action. Dsbs mark the beginning of a cascade of cellular processes that either results in complete repair of the DNA damage or lead to deleterious stages such as mutation, transformation or even cell death. Changing the radiation quality can influence the radiosensitivity of cells in culture. Accelerated particles provide an excellent means of varying the ionization density of the test radiation. With ion beams, the molecular mechanisms underlying the biological consequences of high linear energy transfer (LET) irradiation can be studied and describing radiation action with biophysical models can be tested. In this paper, radiation−induced DNA double−strand breaks (dsbs) were measured in hepatoma SMMC−7721 cells by means of an experimental approach involving pulsed−field gel electrophoresis and densitometric scanning of ethidium bromide stained gels. With this set−up, the induction of dsbs was investigated in SMMC−7721 cells after irradiation with accelerated carbon ions with specific LET 70keV/μm. The fraction of DNA retained was taken as quantitative measure to calculate absolute yields of induced DNA dsbs. Experimental data shows that the induction of DNA dsbs increasing with the dose of irradiation. Data are compared with published results on dsb induction in mammalian cells by radiations of comparable LET.  
        关键词：Carbon ion;Hepatoma cell line SMMC−7721;Double−strand breaks of DNA   
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        发布时间：2023-03-30
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