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1.
探讨12C6+ 离子束辐射对用带有绿色荧光蛋白基因的缺陷性腺病毒(AdCMV GFP)转染小鼠黑色素瘤细胞(B16细胞系)的影响。 采用不同剂量的12C6+ 重离子束辐射经AdCMV GFP 转染的B16细胞, 利用流式细胞仪检测腺病毒的转染率。 结果表明, 12C6+重离子束辐射能提高腺病毒对B16细胞的转染率, 且具有量效关系。 此外, 先转染后辐射法比起先辐射后转染法能更显著地提高转染率。The effect of 12C6+ beam irradiation on AdCMV GFP (a replication deficient recombinant adenoviral vector containing CMV promoter and green fluorescent protein) gene transfection efficiency for murine melanoma cell B16 has been investigated. B16 cells infected with AdCMV GFP were irradiated by different doses of 12C6+ beam. The transfection efficiency was assessed by flow cytometry (FCM). Results show that 12C6+ beam irradiation can improve tansfection efficiency of AdCMV GFP on murine melanoma cell B16 in a dose dependent manner. In addition, the tansfection efficiency in pre tranfection plus irradiation group is higher than that in pre irradiation plus tranfection group at the same dose irradiation dose.  相似文献   

2.
The combination of ionizing radiation and gene therapy has been investigated. However, there are very few reports about the combination of heavy-ion irradiation and gene therapy. To determine if the pre-exposure to low-dose heavy ion beam enhances the suppression of AdCMV-p53 on non-small lung cancer (NSLC), the cells pre-irradiated or non-irradiated were infected with 20, 40 MOl of AdCMV-p53. Survival fraction and the relative biology effect (RBE) were determined by clonogenic assay. The results showed that the proportions of p53 positive cells in 12C6 beam induced AdCMV-p53 infected cells were more than 90%, which were significantly more than those in γ-ray induced AdCMV-p53 infected cells. The pre-exposure to low-dose 12C6 beam significantly prevented the G0/G1 arrest and activated G2/M checkpoints. The pre-exposure to 12C6 beam significantly improved cell to apoptosis. RBEs for the 12C6 AdCMV-p53 infection groups were 30%-60%, 20% -130% and 30%-70% more than those for the 12C6 -irradiated only, AdCMV-p53 infected only, and γ-irradiation induced AdCMVp53 infected groups, respectively. The data suggested that the pre-exposure to low-dose 12C6 beam significantly promotes exogenous p53 expression in NSLC, and the suppression of AdCMV-p53 gene therapy on NSLC.  相似文献   

3.
The combination of ionizing radiation and gene therapy has been investigated. However, there are very few reports about the combination of heavy-ion irradiation and gene therapy. To determine if the pre-exposure to low-dose heavy ion beam enhances the suppression of AdCMV-p53 on non-small lung cancer (NSLC), the cells pre-irradiated or non-irradiated were infected with 20, 40 MOI of AdCMV-p53. Survival fraction and the relative biology effect (RBE) were determined by clonogenic assay. The results showed that the proportions of p53 positive cells in 12C6+ beam induced AdCMV-p53 infected cells were more than 90%, which were signifi-cantly more than those in γ-ray induced AdCMV-p53 infected cells. The pre-exposure to low-dose 12C6+ beam significantly prevented the G0/G1 arrest and activated G2/M checkpoints. The pre-exposure to 12C6+ beam significantly improved cell to apoptosis. RBEs for the 12C6+ + AdCMV-p53 infection groups were 30%-60%, 20%-130% and 30%-70% more than those for the 12C6+-irradiated only, AdCMV-p53 infected only, and γ-irradiation induced AdCMVp53 infected groups, respectively. The data suggested that the pre-exposure to low-dose 12C6+ beam significantly promotes exogenous p53 expression in NSLC, and the suppression of AdCMV-p53 gene therapy on NSLC.  相似文献   

4.
P53及其相关蛋白对X射线照射肝癌细胞周期的调节   总被引:1,自引:0,他引:1  
X射线照射人肝癌细胞HepG2, 照射后细胞存活随照射剂量增大明显下降。 流式细胞术分析, 不同剂量组照射后24 h均发生G2期阻滞。 照射后不同时间组的细胞周期分布也有不同, 照射后12 h, 有显著的S期延迟。 Western Blot 显示照射后24 h P53, MDM2, P21蛋白表达上升, 并有时间效应: P53在照射后24 h之内始终维持较高表达, MDM2和P21分别在照射后6和12 h的表达最高。 X射线照射通过影响P53及其相关蛋白的表达影响细胞周期。 HepG2 cells were irradiated with X ray at the doses of 0, 1.0, 2.0, 4.0 or 8.0 Gy and separately maintained in DMEM at 37 ℃ for 0, 6, 12 or 24 h. Colony forming assay showed that cell survival decreased with the irradiation dose increasing. Cell cycle was detected by FACS, the arrest of S phase was found after 12 h irradiation and arrest of G2 phase took place at 24 h after all irradiation doses, which suggested that cell cycle distribution was different in groups gathered after different maintaining time. The results of Western blotting showed that the expression of P53, MDM2 and P21 increased more after irradiation than the control. The expression of P53 remained high at 24 h after irradiation, while the levels of MDM2 or P21 arrived at the highest at 6 h or 12 h after irradiation respectively. The expressions of P21 after irradiation were in corresponding with the cell cycle distribution in the groups of different maintaining time. In conclusion, irradiation change the distribution of cell cycle by effecting the expression of P53 and its related proteins.  相似文献   

5.
以低剂量γ射线(0.05 Gy)预照射人肝癌细胞hep G2, 8 h后再用高剂量(3 Gy)照射, 测定了细胞的克隆存活率和细胞周期。 结果表明, 低剂量辐射预处理可诱导hep G2细胞产生克隆存活适应性反应, 并且有助于细胞通过G2/M期阻滞; 低剂量辐射诱导的克隆存活适应性反应与增强的通过细胞周期阻滞的能力之间有一定的相关性。 Human hepatoma cells hep G2 were irradiated with 3 Gy of γ ray 8 hours after primed with 0.05 Gy of γ ray, thereafter,cell survival and cell cycle were determined. The results indicated that both survival adaptive response and the enhanced ability to overcome G2/M arrest could be induced by pre irradiation with low dose of γ ray. It is suggested that there is a certain correlation between the survival adaptive response and the enhanced ability to overcome cell cycle arrest.  相似文献   

6.
研究了和厚朴酚(HNK)对非小细胞肺癌(NSCLC)细胞系A549和H1299对低线性能量转移(LET) X射线和高LET碳离子的辐射增敏效应。首先用CCK-8检测了HNK对A549和H1299细胞的生长抑制情况,发现20 μmol/L的HNK处理对细胞的生长抑制作用较弱。用该浓度HNK预处理细胞2 h后给予不同剂量X射线或碳离子的照射,克隆存活法检测细胞的辐射敏感性,Annexin-PI双染法检测细胞凋亡,γH2AX焦点法检测DNA的双链断裂(DSB)损伤。实验结果显示:与X射线相比,NSCLC细胞对碳离子更敏感,HNK预处理仅对碳离子照射有辐射增敏作用;与碳离子单独照射相比,HNK预处理联合碳离子照射诱导了更明显的细胞凋亡;在照射后24 h,HNK预处理联合碳离子照射引起的细胞γH2AX焦点阳性率维持在较高水平,而X射线照射没有这些效应。实验结果表明,HNK预处理抑制了NSCLC细胞DNA的DSB修复,诱导了细胞凋亡的发生,从而提高了细胞对碳离子的辐射敏感性。The radiosensitizing effect of Honokiol (HNK) on non-small cell lung carcinoma (NSCLC) cell lines A549 and H1299 to low-linear energy transfer (LET) X-rays and high-LET carbon ions was investigated in this study. First, the inhibitory effects of HNK on the growth of A549 and H1299 cells were detected by CCK-8 assay, and 20 μmol/L HNK treatment was found to induce a growth inhibitory effect slightly in these two cell lines. Cells were pre-treated with HNK and then irradiated with X-rays and carbon ions of different doses. Cellular radiosensitivity, apoptosis and DNA damage were analyzed by clonogenic survival, Annexin-PI staining and γH2AX foci, respectively. The results showed the cells were more sensitive to carbon ion irradiation compared to X-rays and the radiosensitization of HNK was only observed after carbon ion irradiation. Furthermore, the co-treatment led to higher apoptosis rate 48 h after irradiation and increased the positive rate of γH2AX foci 24 h after irradiation in A549 and H1299 cells compared with those in the groups treated with carbon ion irradiation alone. These phenomena were not observed after X-ray irradiation. Our data suggest that the pre-treatment with HNK inhibited DNA DSB repair, induced apoptosis and then enhanced the cellular radiosensitivity to carbon ions in NSCLC cells.  相似文献   

7.
This paper presents the results of a study that compares CTOM, a microscopic optical model potential(OMP), which is an optical model co-created by the China Nuclear Data Center & Tuebingen University, to CH89, which is a typical phenomenological OMP.The respective OMPs were tested by applying them to the modelling of nucleon elastic scattering and(d,p) transfer reactions involving14C,36S, and58Ni targets at both low and relatively high energies. The results demonstrated that although both potentials successfully accounted for the angular distributions of both the elastic scattering and transfer cross sections, the absolute values of the transfer cross sections calculated using CTOM were approximately 25% larger than those calculated using CH89. This increased transfer cross sections allowed CTOM to produce single particle strength reduction factors for the three reactions that were consistent with those extracted from(e,e′p) reactions as well as with more recent(p,2p) and(p,pn) reactions. Notch tests suggested that nucleon elastic scattering and transfer reactions are sensitive to different regions of the OMP;accordingly,phenomenological OMPs, which are constrained only by elastic scattering cross sections, may not be sufficient for nucleon transfer reactions. Therefore, we suggest that microscopic OMPs, which reflect more theoretical considerations, should be preferred over phenomenological ones in calculations of direct nuclear reactions.  相似文献   

8.
本研究旨在探讨羧甲基-β-1,3葡聚糖(CMG)对人肝癌HepG2细胞X射线或12C6+离子束辐射敏感性的影响。首先用CCK-8法检测CMG对HepG2细胞的生长抑制情况,得到半数抑制浓度(IC50)为120.6μg/mL。用浓度为0.1×IC50的CMG预处理HepG2细胞24 h,再给予2 Gy X射线或12C6+离子束辐照(CMG+辐照组);CMG未处理组直接接受2 Gy X射线或12C6+离子束辐照(辐照组)。对比分析辐照组和CMG+辐照组细胞的克隆存活、DNA损伤、凋亡与周期分布、细胞内活性氧(ROS)水平。发现:与X射线辐照组相比,相同剂量的12C6+离子辐照组克隆存活率更小,DNA损伤和周期阻滞更加严重,细胞凋亡率和细胞内ROS水平也更高。与单独X射线或12C6+离子束辐照组相比,CMG+辐照组克隆存活率明显降低,细胞凋亡率随辐照后CMG作用时间的延长而明显增加,CMG使辐照后细胞内ROS维持在一个较高的水平,同时CMG明显加重了单独辐照诱导的DNA损伤和周期阻滞。结果表明,与X射线相比,HepG2细胞对相同剂量的12C6+离子辐射更敏感;CMG可增加HepG2细胞对X射线或12C6+离子辐射的敏感性;CMG可能通过增加受照HepG2细胞内的ROS水平,加剧辐照诱导的DNA损伤,促进辐射诱导细胞凋亡而起到辐射增敏作用。This study aims to investigate the effect of carboxymethy-β-1, 3-glucan (CMG) on the sensitivity of human hepatoma HepG2 cells to X-rays or 12C6+ ions irradiation. First, the inhibitory effect of CMG on the growth of HepG2 cells was detected by CCK-8 assay, and the half maximal inhibitory concentration (IC50) was 120.6 μg/mL. HepG2 cells were pretreated with CMG at a concentration of 0.1×IC50 for 24 h and then irradiated with 2 Gy X-ray or 12C6+ ion beams (CMG + irradiation group). CMG untreated group was directly irradiated by 2 Gy X-rays or 12C6+ ions beam (irradiation group). The clone survival, DNA damage, cell apoptosis, cell cycle distribution, and intracellular reactive oxygen species (ROS) levels in irradiation group and CMG + irradiation group were comparatively analyzed. The results showed that the clone survival rate was lower, DNA damage and cycle arrest were more serious, and the rate of apoptosis and intracellular ROS levels were higher in 12C6+ ions irradiation group than those in the same dose of X-rays irradiation group. Compared with X-rays or 12C6+ ions irradiation group, the clone survival rate of CMG + irradiation group was significantly decreased, and the apoptosis rate significantly increased with the prolongation of CMG treatment post-irradiation; CMG maintained intracellular ROS at a higher level after irradiation, CMG also significantly aggravated radiation-induced DNA damage and cycle arrest. These results indicated that HepG2 cells were more sensitive to 12C6+ ions radiation than those at the same dose of X-rays. CMG increased the sensitivity of HepG2 cells to X-rays or 12C6+ ions irradiation by increasing intracellular ROS level, exacerbating radiation-induced DNA damage and promoting radiation-induced apoptosis in irradiated HepG2 cells.  相似文献   

9.
The effects of 12C+6 ion irradiation on colony morphology and mycelia morphology, as well as on mutation rate have been studied in the B1a high-product strains (ZJAV-Y1-203) mutated by heavy ion irradiation and compared with that in the original strain (ZJAV-A-1). After irradiating the rate of a straw hat colony type having a high ability of producing B1a in ZJAV-Y1-203 strains was higher than that found in ZJAV-A-1 strains. When strains were cultured in a liquid medium for 24 hours, the mycelium becoming thinner could be observed in all of the irradiated ZJAV- Y1-203 groups, but only in the ZJAV-A-1 groups irradiated at the dose of 50 Gy or more. The early growth of mycelium was inhibited in the ZJAV- Y1-203 group irradiated with a high dose. The highest positive mutation rate (23.5%) of ZJAV - Y1 - 203 was reached at the lower dose of 30 Gy while the highest positive mutation rate of 34.2% in ZJAV-A-1 appeared at 50 Gy.  相似文献   

10.
由于低能离子较低的组织穿透能力, 其诱变机理一直是研究者争论的问题。 近年来, 本研究组的一系列研究工作已经证明在植物中存在辐射远程(诱变)效应, 从一个新的角度解释了低能离子的诱变机理, 然而依然无法解释低能离子辐照中的许多独特生物现象, 而这些现象均具有明显的表观遗传学特性。 以表观遗传学最具标志性特征的胞嘧啶甲基化为研究对象, 以α粒子 拟南芥菜根辐照实验体系作为研究平台, 检测了远程组织(器官)甲基化相关基因 AtDML3 的表达及特定基因片段的甲基化水平。 研究证实, 在植物个体水平辐射可以诱导远程表观遗传的变化, 为进一步探索低能离子的诱变机理提供了新的思路。 Along the way, the mutagenic mechanism of low energy ions irradiation is a debatable issue. Recently, the existence of radiation induced long range (mutagenic) effects in vivo in plants has been performed in a series of studies of our group, which account for the mutagenesis of low energy ions irradiation in a new perspective. However, numerous distinct biology phenomena remain to be addressed, which bear obvious characteristics to epigenetic. In the present study, using the expression of methylation related AtDML3 gene and methylation level of specific gene segments as end points, the methylation of cytosine, the most important feature of epigenetic, was investigated. It was shown that, in A. thaliana, root loca lized α irradiation could induce epigenetic changes in aerial parts which avoided the direct irradiation. The radiation induced long range epigenetic changes were confirmed in this study, which supplied innovative ideas for the further investigation of the mutagenetic mechanism of low energy ions irradiation.  相似文献   

11.
对类金刚石 (以下简称 DLC)薄膜受 γ射线与 N离子辐照的结果进行了比较 .通过 Raman光谱分析得出 :γ射线辐照造成薄膜中 SP3C— H和 SP2C— H键的减少及 SP3C— C键的增加 ,与此同时氢原子结合成氢分子 ,并从膜中释出 ,薄膜的类金刚石特征更加明显.当辐照剂量达1 0×104Gy时 ,SP3C—H键减少了约 5 0 % .N离子辐照使 DLC薄膜中 SP3C— C键、SP2 C—H键及 SP3C—H键的含量均变少 ,并伴随着氢分子的释出 ,直接导致 DLC薄膜的进一步石墨化,其对 SP3C—H及 SP2C— H键的破坏程度远大于γ射线 .两者在辐照机理上截然不同.The results of the diamond like carbon films(the following is called for short DLC film) irradiated by γ rays and N ion were reported. It showed that SP 3C—H and SP 2C—H bonds were decreased, and SP 3C—C bonds were increased by γ ray irradiation, and induced hydrogen recombination with H 2 molecules, and subsequently released from the surface of the films. When the γ ray irradiation dose reached 10×104Gy, the numbers of SP3C—H bonds were decreased by about 50%...  相似文献   

12.
以人肝癌细胞系和正常肝细胞系为材料,报道了不同传能线密度射线辐射引发细胞染色体原初断裂及24 h内的修复情况。 计算了相对生物学效应的值。 以L02染色体总断裂数量得出的RBE值96.05 keV/μm的12C6+ 为3.6, 512 keV/μm 36Ar18+ 为2.9。 而以7721染色体总断裂数量得出的RBE值: 96.05 keV/μm的12C6+ 为3.5,512keV/μm 36Ar18+也为2.9。用产生等点染色单体断裂计算,则RBE更高。对比得出,高LET对增加等点染色单体断裂量的作用要远远大于对增加染色单体断裂量的作用。等点染色单体的断裂修复难度要远远大于染色单体断裂的修复难度, 这也是高LET高致死率的一个重要原因。 Human hepatoma SMMC 7721 and normal liver L02 cells were irradiated with γ rays,12C6+ and 36Ar18+ ion beams at the Heavy Ion Research Facility in Lanzhou(HIRFL). We reported the kinetic repair of chromosome breaks of L02 and SMMC 7721 cells in 24 h of post irradiation time. The relative biological effectiveness(RBE) for inducing chromatid breaks were 3.6 for L02 and 3.5 for SMMC 7721 cell lines at the linear energy transfer(LET) peak of 96.55 keV/μm 12C6+ ions, and 2.9 (both of the two cell lines) at 512 keV/μm 36Ar18+ ions.It suggested that the RBE of isochromatid type breaks induced by 36Ar18+ was higher than those by 12C6+. We concluded that the high production of isochromatid type breaks, induced by the densely ionizing track structure, could be regarded as a signature of high LET radiation exposure.  相似文献   

13.
ALICE光子谱仪光子判别能力模拟研究   总被引:1,自引:0,他引:1  
光子判别能力是ALICE光子谱仪PHOS的重要性能指标之一. 利用ALIROOT软件包对0.5—100 GeV能量范围随机分布的7种粒子n, p,π+, K+和γ入射到PHOS上时光子判别的效率和纯度进行模拟研究. 在簇射形状分析中, 采用主成分分析方法将7参数分析问题约简为2参数, 并与7参数拓扑分析结果进行了比较. 给出了不同能区中光子判别效率与纯度的关系.The photon discrimination power of the ALICE photon spectrometer is simulated for incident particles n, p,π+, K+and γ with random energy distribution in the range from 0.5 to 100 GeV. The pricipale component analysis method is used to reduce the number of parameters in the shower shape analysis, and the results are compared with that from the seven parameter topology analysis.The efficiency dependence of purity for the photon discrimination is obtained for the deposited energy range 0.5—10, 10—20, 20—50 and 50—100 GeV.  相似文献   

14.
利用辐照质粒DNA构象变化的分子模型,以DNA糖苷酶Fpg和AP核酸内切酶EndoIII识别并切割辐射所致DNA碱基损伤,将其转换为DNA断裂损伤,通过电泳分析DNA分子构象变化,研究比较γ射线、质子和7Li离子诱发DNA集簇性损伤。50Gy以上高剂量γ辐射对质粒DNA的损伤主要表现为单链断裂(SSB)和很少比例的双链断裂(DSB),并能产生一定水平的集簇性损伤。相比之下,高能质子束和高LET的7Li离子直接所致DNA的断裂损伤以及所产生的集簇性碱基损伤比γ射线的要严重,质子10Gy照射就可诱发明显的集簇损伤。  相似文献   

15.
选取对数生长期人肺癌细胞A549接受0—6.0 Gy 碳离子照射, 用克隆形成法检测细胞的存活率; 并于照射后12和24 h收集细胞, 用流式细胞术检测细胞周期各时相的细胞百分比, 观察不同剂量碳离子辐照对A549细胞周期进程的影响。 结果显示: 0—6.0 Gy 碳离子照射后细胞存活率显著下降; 照射后12 h细胞发生G0/G1期阻滞, 而照射后24 h, 1.0 Gy 照射组细胞在G0/G1期阻滞, 2.0—6.0 Gy 照射组细胞在G2/M期阻滞。 上述结果表明, 在A549细胞接受碳离子照射后的12 和24 h内, 1.0 Gy 照射可持续激活细胞G1期检查点, 而2.0—6.0 Gy 碳离子照射后其细胞周期进程是随时间变化的。 To investigate the effects of cell cycle progression of A549 cell induced by 12C6+ ion irradiation at different doses, the survival fractions of the A549 cells were determined by colony forming assay; cell cycles were analyzed by FACS at 12 h or 24 h after irradiation. The results showed that the percentage of survival in the A549 cells decreased with irradiation doses. Compared with control group, the percentage of the cells in G0/G1 phase significantly increased at 12 h after irradiation with different doses of 12C6+ ions. However, at 24 h after irradiation the percentage of the cells in G0/G1 phase significantly increased with 1.0 Gy 12C6+ ions, while the cells showed increasing percentage in G2/M phase with 2.0, 4.0 or 6.0 Gy 12C6+ ions. The results suggested that G1 cell cycle checkpoint was activated in 12—24 h after irradiation with 1.0 Gy 12C6+ ions, but after irradiation with 2.0—6.0 Gy 12C6+ ions, the cell cycle progression of the A549 cells changed with time.  相似文献   

16.
探讨了正常皮肤对重离子辐照急性损伤反应的耐受性, 为重离子治癌临床应用提供安全性检测的实验依据。实验前10 min, 实验猪肌肉注射复方氯胺酮1.2 mg/kg进行麻醉, 然后在兰州重离子研究装置(HIRFL)辐照终端利用12C6+束照射, 辐照剂量分别为0, 12, 21和27 Gy, 辐照分3次完成, 剂量率约为1.2 Gy/min, Bragg峰区照射, 辐照后每隔7 d对照射野拍照并活检取样, 做HE组织病理学观察。不同剂量12C6+离子束辐照实验猪皮肤后, 皮肤外观反应随辐照剂量增大而加快, 表现为肿胀和色素沉积等; 皮肤组织结构的变化明显, 上皮细胞排列紊乱、 萎缩、 空泡变性; 基本恢复正常所需时间也越长, 且都存在明显的剂量效应关系。结果表明, 辐照剂量范围为0—27 Gy时, 重离子对正常皮肤的辐照是安全的。The tolerance of the normal skin to the acute radiation injury reaction induced by heavy ion beams has been studied experimentally. The experimental pigs were injected with 1.2 mg/kg ketamine in 10 min before irradiation and were irradiated with 0, 12 , 21 and 27 Gy 12C6+ ion at a dose rate of 1.2 Gy/min at the Heavy Ion Research Facility in Lanzhou(HIRFL). The total radiation dose was finished by 3 times at Bragg Peak Region of Heavy Ion Beams.The radiation fields of skin were taken photo and performed biopsy. The contaneous tissues of radiation fields were stained by HE and examined histopatholo gical changes every seven days after irradiation. The results indicated that the cutaneous appearance reaction became more faster with radiation dosage rising and presented with swollen, melanin forming and so on after irradiated by the carbon ions at different dosage. The Pathological examination showed noticeable changes in histological and structural of experimental pigs skin, such as atrophy, vacuolation, denaturation and arranged irregularly in epithelial cells. Furthermore, the time for return to normality became longer with the increasing of radiation dosage. All indexes demonstrated correlation between the does and effects. It is concluded that the irradiation of heavy ion beams to normal skin is security when the radiation dose range is about 0—27 Gy.  相似文献   

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