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Objective To study the changes of mRNA and protein expressions of Kras gene in thymic lymphomas induced by ionizing radiation,and to detect the methylation of CpG islands in promoter region of Kras gene,then to investigate the mechanisms for the occurrence of radiation carcinogenesis.Methods The thymic lymphoma models of BALB/c mice were made by X-ray irradiation,then the total RNA was extracted,cDNA was synthesized and the total protein was extracted from both thymic lymphoma tissue and normal thymus tissue;the mRNA and protein expressions of Kras gene in thymic lymphoma tissue and normal thymus tissue were detected by RT-PCR and Western blotting method, and the methylation of CpG islands in promoter region of Kras gene was detected by bisulfite sequencing PCR. Results The mRNA expression level of Kras gene in thymic lymphoma tissue was significantly higher than that in normal thymus tissue(P<0.01).The protein expression level in thymic lymphoma tissue was about 1.41 times higher than that in normal thymus tissue;4 CpG sites were methylated detected by bisulfite sequencing PCR in normal thymus tissue, however, 1 CpG site was methylated in thymic lymphoma tissue,the CpG islands in promoter region of Kras gene were demethylation state in thymic lymphoma. Conclusion Ionizing radiation can cause the changes of mRNA and protein expression levels of Kras gene in thymic lymphoma tissue by demethylation state of Kras gene,eventually lead to the occurrence of tumor;it might be one of the mechanisms for the occurrence of radiation carcinogenesis.
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Objective To study the change of chromosome aberration rate and micronucleus rate in patients with esophageal carcinoma before and after radiotherapy.Methods Twenty one patients with esophageal carcinoma who were fit for conditions were divided into two groups randomly.GroupⅠ(n=10),patients received conventional radiotherapy(radiation field was regular rectangular shape);groupⅡ(n=11),patients received conformal radiotherapy(radiation field was same to the shape of target volume),1.8-2.0 Gy,one time a day,5 times a week,the total dose was 60-70 Gy.The peripheral blood was obtained before and after radiotherapy,chromosome aberration rate and micronucleus rate were detected.Results The chromosome aberration rate and micronucleus rate were increased after conventional radiotherapy than before (P0.05).Conclusion Compared with the conventional radiotherapy,the conformal radiotherapy can decrease cytogenetics damage,the detection of chromosome aberration rate and micronucleus rate can be regarded as a simple method to evaluate cytogenetics damage in esophageal carcinoma patients induced by radiotherapy.
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Objective To study the relationship between CXXC motif and biologic activity of human augmenter of liver regeneration protein(hALRp).Methods The function of CXXC motif and its relationship with bioactivity were investigated between hALRp and hALRp-C65A groups by detecting the sulfhydryl oxidase activity;the interaction of target protein with GST-Na~+,K~+-ATPase fusion protein was examined by GST-Pulldown and MTT was used to study the ability of hALRp-C65A to promote HL-7702 hepatic cells proliferation in vitro.Results The turnover number(TN) of hALRp in sulfhydryl oxidase activity assay was 1.25?0.21,while TN was 0 of hALRp-C65A,there was significant difference between them(P
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Objective To construct pSUPER-SVV vector and obtain its expression in HeLa cells,in order to interfere the expression of survivin.Methods Oligonucleotide sequences specific for survivin were designed for RNA interference(RNAi),after annealed they were ligated to pSUPER.basic vector.After sequencing,the vector of pSUPER-SVV was transfected into HeLa cells by LipofectAmine.The expression of survivin was detected by RT-PCR and FCM.Results The RNAi expression vector of survivin was constructed successfully,which depressed the expression of survivin efficiently.Survivin was significantly depressed on the level of mRNA in HeLa cells compared with the control groups(P
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Objective: To acquire the new clear color phenotype of Aspergillus oryzae b y th e antisense strategy of siderophore regulation protein (SREP)-like gene. Method s: Construct the cDNA library of Aspergillus oryzae RIB40 and amplify the fr agme nt ac7336f from the every EST clone, which had high homology with SREP gene of o ther species, then construct the eukaryotic expression vector with SREP-like ge ne using antisense strategy. Results: The sequence of this SREP-like gene was a cquired, the vector was successfully constructed. Conclusion: The deduced amino acid sequence of SREP-like gene of Aspergillus oryzae indicated that there is t he high homology with those of SREP genes of Penicillium chrysogenum, Neur ospora crassa and Schizosaccharomyces pombe.
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Objective: To explore effect of TfR on immune function after ionizing by investigating changes in TfR expression on splenic lymphocytes of mice after whole body irradiation (WBI) with different dose X-rays. Methods: Direct immunoflurescence antibodies and flow cytometry were used to examine the changes of TfR expression. Results: The cell number of TfR positive expression in spleens increased significantly at 24 hours and 72 hours after WBI with 75 mGy X-rays but the cell number of TfR positive expression in spleens decreased significantly at 24 hours after WBI with 1～6 Gy X-rays. The activity of IL-2, meanwhile, demonstrated a parallel change. Conclusion: These results suggest that the TfR enhances immune function in low dose ionizing radiation but suppresses immune function in high dose. The change of TfR expression may be due to the change of IL-2 activity caused by ionizing radiation.
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Objective: To find out whether or not low dose radiation could induce resistance to challenge dose-induced depression of immune functions.Methods:The following techniques were employed in this experiment:flow cytometry with immunofluorescence for the expression of TCR/CD3 receptor,3H-TdR incorporation technique for the spontaneous proliferation of thymocytes and the mitogen-induced proliferation of splencoytes as well as a bioassay with CTLL cells for IL-2 production.Results:The following optimal conditions for the induction of immunological adaptive response were determined:0.025 to 0.1 Gy for the conditioning doses (D1),1.0 to 1.5 Gy for the challenge doses (D2),and 6 to 12 h for the intervals between D1 and D2.Conclusion:Immunological adaptive response could be induced by low dose radiation.