最新刊期
期 3 ， 2000
- 摘要：The photosensitization effects of tris(bipyridine)ruthenium-(III) on DNA caused by visible light has been studied by using of agarose electrophoresis. In the presence of oxygen, it was found that DNA strand break, which amount was related to the concentration ratios of DNA and tris-(bipyridine)-ruthenium-(III), the DNA fragments appearing induced by tris-(bipyridine)-ruthenium-(III) irradiated with the light wavelength ranged at 427-457nm via base damage mainly resulted from the reaction of DNA with singlet oxygen, which was produced from the reaction between ground state oxygen and excite state of tris-(bipyridine)-ruthenium-(III), and via that from the reaction with cation radical of tris-(bipyridine)-ruthenium-(III). It also shown that the ssDNA did more easily break than that of dsDNA, which might be due to the more base accessible in ssDNA.关键词：Tris-(bipyridine)-ruthenium(III);Photosensitization damage;Electrophoresis;ssDNA;dsDNA
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发布时间：2023-04-07 - 摘要：Grafting copolymerization of mixture of acrylic acid (AA) and sodium styrene sulfonate (SSS) onto high density polyethylene (HDPE) membrane was studied by the mutual γ-irradiaton technique. At last we prepared a strong acid cation exchange membrane by one-step method. Sufficient amounts of AA groups could be grafted onto the surface of PE firstly and the hydrophilicity of the surface was improved. By studying the grafting of SSS and the mixture of AA and SSS onto PE, we found SSS could not graft onto PE without AA. In this article, grafting conditions as well as dose, the effects of monomers feed composition and total concentration of monomers were discussed. The mechanical and chemical properties of membranes were also tested.关键词：Polyethylene;Acrylic acid;Sodium styrene sulfonate;Mutual irradiation technique;Strong acid cation exchange membrane
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发布时间：2023-04-07 - 摘要：In order to investigate the role of lexA gene in the radioresistance of Deinococcus radiodurans, the expressing vector of lexA gene was constructed. The genomic DNA was extracted from wild type Deinococcus radiodurans KD8301. The lexA gene was isolated from the genomic DNA and sequenced. The Plasmid vector pUC19 was used to clone lexA gene and the electroporation was employed to transfer the recombinant plasmid into E. coli JM109. SDS-PAGE was used to check the expression of lexA gene. The ribosome binding site (RBS) of lexA gene was mutated by means of Site -Directed Mutagenesis technique for the optimum of gene expression. The results indicated that the lexA gene was located in the Blnl-AscI fragment of Deinocococus radiodurans genomic DNA, containing 630bp and coding 210 aa. The theoretically deduced molecular weight and the isoelectric point were 2.5KDa and 6.4 respectively. lexA gene inserted into pUC19 could be expressed in JM109, but at very low level. After optimizing the RBS of lexA gene, higher level of lexA expression was obeserved. The results make it possible to isolate and purify lexA protein, and further to investigate the function of lexA gene in Deinococcus radiodurans.关键词：Deinococcus radiodurans;LexA gene;Gene cloning;Gene expression
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发布时间：2023-04-07 - 摘要：Pulsed-field gel electrophoresis has been applied to analyse the induction and repair of DNA double-strand breaks (DSB) in human hepatoma SMMC-7721 cells exposed to 3.17MeV/u 16O6+. It shows that the DSB yields are 0.43DSBs/100Mbp/Gy and compared with 60Co γ-rays, the relative biological effectiveness (RBE) of 16O6+ is 1.69. The half time of DSB fragments being repaired (t1/2) is relevant to the dose; the higher the dose is, the longer the time is. The main way for DSB repair is the rejoining of smaller fragments into larger ones.关键词：16O6+;DNA double-strand breaks;Pulsed field gel electrophoresis;Human hepatoma cells
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发布时间：2023-04-07 - 摘要：To study the differentially expressed genes correlative to irradiation-induced damage in mouse intestinal tract and its repair by foreign mouse small intestinal RNA. Divide 90 mice into 4 groups randomly. For the experimental groups, each mouse was given 40µg foreign mouse small intestinal RNA, and for the control groups, 0.4mL of 0.9% NaCl. The intestinal specimens were collected form each group 6h, 12h, 24h, 4d and 8d after 60Co γ-rays irradiation respectively. The differentially expressed genes in the tested and control groups were checked and cloned by long-distance PCR based on subtractive hybridization. 165 differential gene clones were obtained, of which 75 named as AXCZI-75 maybe were correlated with the irradiation-induced damage in mouse intestinal tract; and 90 named as XCZ1-90 maybe were correlated with repairing of the damaged mouse intestinal tract by foreign mouse small intestinal RNA.关键词：Mice;Irradiation;Damage;Renovate;Expressed genes;Subtractive hybridization;Long-distance PCR
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发布时间：2023-04-07 - 摘要：To explore the molecular mechanism of G1 arrest of EL-4 cells induced by whole body irradiation (WBI), Flow cytometry (FCM) and Northern blot were used to analyze p53, MDM2 gene expressions of EL-4 cells after irradiation with X-rays. Results showed that the p53 protein level of El-4 cells increased from 2 to 24h, and the MDM2 protein level of El-4 increased from 4 to 24h after 4Gy irradiation with X-rays. Meanwhile, the MDM2 mRNA level was significantly increased at 4h after irradiation. Conclusion: these results suggested that there was a feedback loop between p53 and MDM2 protein in EL-4 cells after irradiation with X-rays, which made G1 arrest cells reenter cell cycle.关键词：Ionizing radiation;EL-4 cells;MDM2;P53
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发布时间：2023-04-07 - 摘要：In order to study the change of receptor signal transduction after irradiation and its relation with growth of irradiated hematopoietic cells, the effects of the inhibitors of protein-tyrosine kinase and phosphatase on irradiated and unirradiated NFS-60 cells were observed by using MTT method. It was showed that the proliferation of NFS-60 cells was promoted by phosphatase inhibitors and suppressed by kinase inhibitors. Compared with unirradiated cells, phosphatase inhibitors had stronger stimulating effects on irradiated NFS-60 cells with 3Gy irradiation, meanwhile some kinase inhibitors might repress the growth of irradiated cells relatively. It was suggested that the homostasis of kinase and phosphatase were out of balance in irradiated NFS-60 cells, which might be one of the reasons for growth repression of hematopoietic cells after irradiation.关键词：Signaling molecular inhibitors;Radiation injury;NFS-60 cells
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发布时间：2023-04-07 - 摘要：To observe the effect of mixed infusion of bone marrow and bone marrow stromal cells on hematopoietic reconstitution in lethally irradiated mice, Balb/c mice irradiated lethally received 1×107 syngeneic bone marrow cells and 2×105 syngeneic bone marrow stromal cells via the intravenous route. As compared with the simple BMT group, the WBC and the BPC in peripheral blood in mixed infusion group recover more quickly on day 14 after BMT and BMSCT. The numbers of CFU-GM, BFU-E, CFU-E, CFU-S in mixed infusion group are higher than that of the simple BMT group on day 15 and day 20 after BMT and BMSCT. Conclusion: primary cultured bone marrow stromal cells not only is transplantable, but also can accelerate hematopoietic reconstitution.关键词：Bone marrow transplantation;Bone marrow stromal cells;In vitro proliferation;Hematopoietic reconstitution
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发布时间：2023-04-07 - 摘要：To study the effects of heat and ionizing radiation on mouse embryos, the LACA mice were exposed to 42℃ for 10min and 1.0Gy 60Co γ rays on the 9th day after gestation, and development of mouse embryos were observed and the contents of DNA, RNA and protein in the brains of mouse embryos were measured on the 18th day after gestation. Results demonstrated that 1.0Gy 60Co γ rays irradiation, compared with control, could induce the development retardation for mouse embryos, and the contents of nucleic acids and protein in brains of mouse embryos irradiated were lwss. Meanwhile 42℃ exposure induce insignificant or less effects. The mouse group with 42℃ treatment followed by 1.0Gy 60Co irradiation showed the efffects at the level between the groups with 42℃ and 1.0Gy irradiation. Thus, exposure of mouse embryos to 42℃ for 10min prior to irradiation may be could induce their adaptive response to irradiation.关键词：Ionizing radiation;Hyperthermia;Mouse embryos;Nucleic acids;Protein
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发布时间：2023-04-07 - 摘要：The interaction of 2-methyl-1, 4-naphthoquinone (MQ) with nucleotides and DNA have been studied using KrF laser photolysis aimed at elucidation of the initial reaction mechanism. Laser spectroscopy demonstrates directly that the initial species from interaction of MQ with nucleotides are radical cations of nucleotides and MQ radical anion. Kinetic analysis indicates that formation of ion pair from interaction of any of mucleotides with MQ is synchronous with decay of triplet MQ, which has provided dynamic evidence for initiation of electron transfer from DNA bases to triplet MQ, while the oxidation of TMP with slowest rate could be the rate determining step during the interaction of triplet MQ with DNA. Moreover direct observation of stabilized DNA guanyl radical cation from interaction of MQ with DNA has provided initial evidence for selective cleavage of DNA at guanine moiety, which has simulated the major, initial species produced by the action of ionizing radiation or UV light on DNA.关键词：DNA;Nucleotide;2-methyl-1,4-naphthoquinone triplet state;Radical ion pair;Transient absorption spectra;Electron transfer oxidation
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发布时间：2023-04-07 - 摘要：To study the expression of c-Fos and Rb in radiation-induced rat skin ulcers. We set up an animal model of radiation skin ulcer with 140 rats which were locally irradiated with 35~55Gy γ rays, and the pathological changes were observed for 1 year. Immunohistochemical studies were performed in 72 rat radiation skin ulcer tissues, and c-Fos, Rb protein polyclonal antibodies were used. The results showed that the positive rate for overexpression of c-Fos was 45.8%, and for that of Rb was 63.9%. The positive position was mainly in the nucleus of activated squamous epithelial cells and in some fibroblasts, endotheliocytes of the arterioles in mesenchyme. It is suggested that the overexpression of c-Fos and Rb proteins might be related to canceration and poor healing in radiation skin ulcers.关键词：Rat;Radiation skin ulcer;Oncogene
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发布时间：2023-04-07 - 摘要：In this study, the effect of whole body irradiation (WBI) with different low doses of X-rays on the expression of Glucocorticoid receptor (GCR) in mouse splenocytes and the time course of GCR expression after WBI with 75mGy X-rays were observed using the radioactive ligand binding assay. Results showed that the GCR expression in mouse splenocytes decreased significantly 8h after WBI with 25, 50 and 75mGy X-ray irradiation, and in the case of 75mGy, the GCR expression began to decrease 4h after irradiation. Based on the fact that WBI with low doses of X-rays could reduce GCR expression in mouse splenocytes, it suggested that the down-regulated GCR expression may play a role in the enhancement of immune effect caused by low dose radiation.关键词：GCR;Splenocytes;X-rays;Low dose radiation
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发布时间：2023-04-07 - 摘要：The TNF-mediated L929 cell toxicity bioassay was used to examine the expression of TNFα in mouse peritoneal macrophages following whole body irradiation (WBI). The expression of TNFα gradually increased after WBI with 0.075Gy, reaching its peak at 12h. The TNFα expression of TNFα gradually increased from 3 to 120h after WBI with 2Gy. The expression of TNFα was significantly increased at 24h after WBI with 0.05, 0.075, 0.1. 0.2, 0.5, 1.0 and 2.0Gy.The expression of TNFα increased most markedly in the group irradiated with 0.5Gy.关键词：X-ray irradiation;Peritoneal macrophages;Tumor necrosis facfor α
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发布时间：2023-04-07
- 摘要：ABSTRACT The effect of whole-body X-irradiation on the transcription and expression level of genes related to cell survival and cell cycle control, the transcription level of genes related to immune responses as well as the signal molecules of mouse thymocytes and/or splenocytes was reviewed. Opposite effects from low versus high doses of irradiation were demonstrated in most of the parameters examined. The implications of these changes in connection with the cellular responses after different doses of ionizing radiation were analyzed.关键词：KEYWORDS Radiation;Genes;Cell survival;Cytokines;Cell cycle control;Signal transduction
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发布时间：2023-04-07 - 摘要：ABSTRACT An animal model of radiation-induced skin ulcer was set up with 140 rats, which were locally irradiated with 35～55Gy γ-rays. The pathological changes were observed for 1 year. Immunohistochemical studies were performed in 72 rat radiation skin ulcer specimens using anti-p53 and anti-MDM2 protein polyclonal antibodies. The results showed that the positive rate for overexpression of p53 protein was 9.7%, and for that of MDM2 was 19.4%. The overexpression of p53 was mainly seen in the nuclei of activated squamous epithelial cells, and in fibroblasts, endotheliocytes in deeper part of the skin ulcers. The overexpression of MDM2 had the same localizations. It's suggested that the changes of p53 and MDM2, genes and proteins, may be related to the cancer transformation and poor healing of radiation-induced skin ulcers.关键词：KEYWORDS Rat;Radiation skin ulcer;P53;MDM2
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发布时间：2023-04-07
研究论文
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