γ射线对肝癌细胞G2染色体的原初损伤

用Calyculin—A诱导的早熟染色体凝集技术研究了γ射线诱导人肝癌细胞株HepG2细胞G2期染色体的原初损伤。结果表明:G2等点染色单体断裂畸变与辐射剂量呈线性平方关系,G2染色单体断裂畸变和G2期染色单体断裂畸变总数与辐射剂量呈线性正相关关系,发生各类断裂畸变的细胞率与剂量也呈线性正相关关系。γ射线诱发的断裂畸变主要是G2染色单体断裂畸变,断裂畸变的细胞主要是发生G2染色单体断裂畸变。A chemically induced premature chromosome condensation technique with Calyculin-A has been employed to estimate the initial chromosome damage in HepG2 condensed in G2 phase and the percentage of aberrant cells after exposure to γ-rays. The results show that the dose-response for iso-chromatid breaks is linear-quadratic manner, while chromatid-type breaks and total chromatid breaks show a positive linear dose-response. The percent tages of all kinds of aberrant cells are increasing linearly with increasing doses. G2 chromatid-type breaks and the percentage of G2 chromatid-type aberrant cells are predominate in G2 total chromatid breaks induced b y γ-rays.     

人肝癌SMMC-7721细胞对低剂量γ射线辐射超敏感性的研究

研究了人肝癌细胞SMMC-7721在低剂量γ射线照射下超敏感性和增强的辐射抗性响应。选用对数生长期细胞接受0—6 Gy不同剂量的^60Coγ射线的照射。利用流式细胞仪对细胞进行分选计数,并用克隆形成法检测细胞存活率。发现SMMC-7721细胞存在低剂量辐射超敏感性和增强的辐射抗性响应,即在0—0．3Gy之间细胞表现出单位剂量杀伤增强现象,在0．3—1Gy细胞表现一定的辐射抗性,在1Gy以上,细胞的存活符合线性平方模型。     

不同LET射线对细胞的生物学效应

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.     

利用超分次技术进行肿瘤治疗的探讨

以人类肝癌细胞SMMC-7721和正常肝细胞L02为研究对象，以这两种细胞0．3Gy时超敏感性的存活数据为基础，从理论上探讨了γ射线照射时，用超分次技术治疗肝癌的可能性。经过计算发现:如果目标肿瘤和周围的正常组织超敏感性的存活差异提高到3％，即可利用超分次技术对肿瘤进行治疗。应用超分次进行分次照射时，照射的结果与分次的间隔时间有关。对这一现象的机理进行了一定的探讨，发现时间间隔与细胞G2期的长短可能存在一定的相关性。Based on the survival data of human hepatoma SMMC-7721 and normal liver L02 cells irradiated with γ-rays at 0.3 Gy and 2 Gy, the possibility of uhra-fractionated radiotherapy is discussed in this paper. According to calculations, it is found that if the difference in cell survival between target tumor and adjacent normal tissue is up to 3%, radiotherapy using HRS would be realized through uhra-fractionation. Furthermore, the low-dose response is time-dependent. After analyzing this phenomenon, it was pointed that there would be a correlation between fractionation interval and the duration of cell G2 phase.     

拉曼光谱研究复方鹿仙草颗粒对SMMC-7721肝癌细胞的作用

应用拉曼光谱研究了不同浓度的鹿仙草溶液与肝癌细胞SMMC-7721的相互作用,通过对药物作用前后细胞的光谱变化进行分析,从而为阐明鹿仙草与肝癌细胞的作用方式提供重要的依据。拉曼光谱显示,加入鹿仙草后,细胞的许多峰都发生了变化。归属于磷酸骨架振动的785和1 092 cm-1的两个峰强度下降,对应碱基A和G的峰1 312和1 585 cm-1 等也有不同程度的降低,表明鹿仙草可能插入DNA碱基对之间,使DNA复制受到抑制,导致细胞DNA含量下降,而且会引起DNA单、双链的断裂。同时,研究还发现属于蛋白质的振动峰(1 005, 1 360, 1 656 cm-1)强度也有不同程度下降,说明蛋白质二级结构以及侧链氨基酸的环境均发生了改变。此外,鹿仙草对细胞的作用效果随浓度增加逐步增强。     

γ射线辐照人类正常肝细胞染色体损伤的动态修复

应用早熟染色体凝集技术对人类正常肝脏细胞经γ射线照射导致的染色体损伤后48h内的动态修复过程进行了研究。结果显示:照射后原初染色单体断裂和等点染色单体断裂数随着照射剂量的增加而增多，染色单体断裂显著多于等点染色单体断裂；经过24h的继续培养，这两种类型的损伤都有不同程度的修复，约50％染色单体断裂得到修复，而等点染色单体断裂的修复率最多为15％；经过48h的照射后培养，染色体损伤的水平与24h相比没有显著差异。说明肝细胞经γ射线照射后染色体损伤的主要形式是染色单体断裂，易于修复；虽然等点染色单体断裂数量较少，但修复困难。由此表明，等点染色体断裂是细胞经γ射线照射后死亡和癌变的一个重要因素。We employed the prematurely chromosome condensation （PCC） technique to investigate the 48 h kinetic repair of normal human liver cell line L02 exposed to γ-rays. The results showed that chromatidtype and isochromatid-type breaks increased with the dose at 0 h measured by PCC, the number of chromatid-type breaks was several times more than that of isochromatid-type breaks. Further 24 h incubationafter exposed to irradiation, both of these two type breaks decreased in different extent, 50% for chromatid-type one, change of the the main type easy to repair. 15% for isochromatid-type one at most, respectively. chromosome breaks compared with that of 24th h（p〉 0. 05 of the chromosome breaks was chromatid-type after exposed 48th h, there was a slightly ）. These results revealed that to low LET rays, also, it was Though the isochromatid-type breaks was obvioously less than that of the chromatid-type one, it was difficult to repair. It implied that the isochromatid-type breaks was the important factor causing cell death and canceration when cells were exposed to irradiations.     

细胞的原子力显微镜最佳成像条件研究

通过对不同处理条件和测试条件下人肝癌细胞SMMC-7721的原子力显微镜图像的分析和研究,得到了在大气环境和溶液环境中肝癌SMMC-7721细胞的最佳成像条件,同时建立了用原子力显微镜观测活细胞的实验方法.使用0.5%、1%、1.5%的戊二醛溶液固定细胞后再漂洗,变换原子力显微镜的扫描模式,调节扫描参量并在大气环境下观测以寻找该环境下的最佳成像条件；将用多聚赖氨酸处理基底后的培养细胞直接放置于生理溶液中用原子力显微镜进行溶液环境观测,比较扫描时限并分别改变环境液体类型、探针以及扫描频率,比较了不同条件下原子力显微镜图像的差异,在得出最优参量的同时对其相关原理进行了分析,建立了活细胞实时观测的实验方法.比较两种条件下的细胞图像发现,戊二醛溶液固定过的细胞与生理溶液环境中的活细胞有很大差别,在生理溶液条件下的细胞饱满,可见到光滑清晰的细胞边缘；但戊二醛溶液固定的细胞表面粗糙,细胞边缘不清晰,表明固定后观测到的细胞与生理状态下活细胞的表面形貌存在很大差异.     

低剂量辐射诱导hepG2细胞克隆存活和细胞周期适应性反应

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.     

重离子辐射哺乳动物细胞敏感性的分子机理

研究了用传能线密度125.5keV/μm的12C6+辐照小鼠黑色素瘤、中国仓鼠肺、人的宫颈癌、人的肝癌细胞的敏感性以及DNA双链断裂和DNA双链断裂片段分布,结果表明细胞敏感性与DNA双链断裂之间没有一致的关系,提出了细胞辐射敏感性的一种可能的分子机理,即DNA序列敏感性位点协同DNA双链断裂互补性机理.由此解释了4种细胞系的不同敏感性问题. Four types of cells, melanoma B16, cervical squamous carcinima HeLa, Chinese hamster V79 and hepatoma SMMC 7721, were irradiated by 125.5 keV/μm carbon ions. Celullar sensitivities to irradiation indicated by D50 , DNA double strand break (DSB) and distribution of DSB fragments expressed by molecular weight are studied. The results show that there is not a consistent relationship between cellular sensitivity and DNA DSB induction, a possible molecular mechanism of radiosensitivity which...     

水声目标辐射噪声的局部线性预测分析

从动力学的观点,对水声目标辐射噪声进行相空间的局部线性预测。计算了辐射噪声序列的平均预测误差与邻域大小的关系曲线,从曲线的类型可判断辐射噪声序列的线性性,并得到合适的预测函数类型及参数。文中对线谱和连续谱成分分别进行了局部预测。此外,还讨论了使预测误差最小的模型参数的选取。     

Radiobiological response of human hepatoma and normal liver cells exposed to carbon ions generated by Heavy Ion Research Facility in Lanzhou

Human hepatoma and normal liver cells were irradiated with ¹²C⁶⁺ ion beams (LET = 96.05 keV/μm) and γ-rays at Heavy Ion Research Facility in Lanzhou (HIRFL). The chromatid breaks and break types were detected using the premature chromosome condensation technique. Our experimental results showed that chromatid breaks seem to have a good relation with ¹²C⁶⁺ absorbed dose and ¹²C⁶⁺ are more effective to induce chromatid breaks as compared to the γ-rays. For ¹²C⁶⁺ ion irradiation the major break was isochromatid break, while chromatid breaks were dominant for γ-ray irradiation. We also observed that the Relative Biology Effectiveness (RBE) of ¹²C⁶⁺ ion is about 2.5 times higher than that of γ-rays.     

Tuneable magnetic properties of hydrothermally synthesised core/shell CoFe2O4/NiFe2O4 and NiFe2O4/CoFe2O4 nanoparticles

The aim of this study was to prepare a novel targeting nano drug delivery system of 2-methoxyestradiol (2-ME) based on the folic acid-modified bovine serum albumin, in order to improve the clinical application disadvantages and antitumor effect of 2-ME. In this study, 2-methoxyestradiol-loaded albumin nanoparticles (2-ME-BSANPs) were prepared by desolvation method, and then the activated folic acid was conjugated to 2-ME-BSANPs by covalent attachment (2-ME-FA-BSANPs). The size and zeta potential of 2-ME-FA-BSANPs were about 208.8 ± 5.1 nm and ?32.70 ± 1.01 mV, respectively. 2-ME loading efficiency and loading amount of the nanoparticles were 80.49 ± 3.80 and 10.25 ± 1.59 %, respectively. SEM images indicated that 2-ME-FA-BSANPs were of a round shape, similar uniform size, and smooth surface. Studies on drug release indicated that 2-ME-FA-BSANPs had the properties of sustained and controlled release, which provided them with the ability to fight continually against cancer cells. Internalization analysis demonstrated that 2-ME-FA-BSANPs-targeting drug delivery system could get efficiently transferred into the cells through the folic acid-mediated endocytosis, leading to higher apoptosis and affording higher antitumor efficacy against SMMC-7721 cells in vitro compared with 2-ME alone. Furthermore, the cell-cycle arrest of 2-ME-FA-BSANPs on the SMMC-7721 cells occurred at G2/M phase, and 2-ME-FA-BSANPs did not change the inhibition of the tumor mechanisms of 2-ME. Based on these results, it was concluded that albumin nanoparticles could be the promising nano carrier for 2-ME, and 2-ME-FA-BSANPs-targeting drug delivery system may be promising candidate for providing high treatment efficacy with minimal side effects in future cancer therapy.     

新光敏剂铝酞菁与人癌细胞作用的荧光研究

本文对用于光动力癌症疗法(PPT)的新光敏剂铝酞菁(AlSPC)与人癌细胞的作用进行了实验探讨。细胞荧光光谱的测定及荧光强度的定量表明,铝酞菁能被人癌细胞所吸收,且经40μg/mlAlSPC培育24小时后,细胞对AlSPC吸收的量级为3.47μg/107细胞。对人癌细胞的光敏杀伤显示,杀伤效果正比于光敏剂培育浓度与光辐照剂量。由脂质过氧化的荧光研究表明,经光敏反应后人癌细胞膜的脂质过氧化代谢产物丙二醛(MDA)明显增高,揭示在AlSPC光敏反应中有活性氧作用。色氨酸降解的荧光实验证实,在光敏反应中有单线态氧(1O2)的生成。     

The effects of lipid A on gamma-irradiated human peripheral blood lymphocytes in vitro

The modulatory effects of lipid A (diphosphoryl lipid A (DLA) and monophosphoryl lipid A (MLA)) on apoptosis induction and DNA structure damage (single and double-strand breaks (SSBs and DSBs, respectively)) in peripheral human blood lymphocytes are studied for ⁶⁰Co gamma-irradiation. It is shown that in the presence of these agents the amount of apoptotic cells increases compared with the irradiated control samples. The effect is most strongly pronounced for DLA. In its presence, a significant increase is observed in the number of radiation-induced DNA SSBs and DSBs. Possible mechanisms are discussed of the modifying influence of the used agents on radiation-induced cell reactions