某氡温泉周边居民外周血淋巴细胞微核的变化

目的 观察氡温泉周边居民外周血淋巴细胞微核率,为氡温泉对健康是否有影响提供依据。 方法 采用简单随机抽样法抽取某地氡温泉周边居民42人;同时简单随机抽取生活习惯相似,但未接触过氡温泉的居民44人。采用胞质分裂阻断微核法检测两组居民外周血淋巴细胞微核。 结果 氡温泉组的微核率（u=8.26,P＜0.01）和微核细胞率（χ2=47.76,P＜0.01）均值显著高于对照组。氡温泉组微核率和微核细胞率随着年龄的增加而增加,且差异具有统计学意义（χ2=44.034、27.739,P＜0.01）。氡温泉组女性的微核率（u=7.98,P＜0.01）和微核细胞率（χ2=37.123,P＜0.01）均高于男性且差异具有统计学意义。控制年龄、性别、吸烟和饮酒等混杂因素后,氡暴露与微核率呈高度正相关（χ2=57.68,P＜0.01）。 结论 高氡温泉能够引起居民外周血淋巴细胞微核率增加。     

慢性放射损伤简易诊断指标-畸变细胞率和微核细胞率

工作试探讨骨髓分裂畸变细胞率和有核细胞微核细胞率能否敛为放射损伤的简易诊断指标。观察材料为骨髓涂片,其中24例为正常健康人,10例慢性放射病和59例血液病患者。 观察缩果表明畸变细胞率和微核细胞率增高可考虑作为诊断慢性放射损伤的参考指标。与血细胞的畸变分析比较,这两个指标具有操作简便,出结果快的优点。     

357例放射工作人员外周血淋巴细胞微核分析

对淋巴细胞微核率的观察，不仅能早期发现辐射效应，而且还能对受照个体进行生物剂量估算。随着电离辐射装置的改进及辐射防护措施的加强，放射工作人员受照剂量逐年降低。为探讨低剂量电离辐射对放射工作人员细胞遗传学的影响，笔者于2003年11—12月对濮阳市放射工作人员进行了外周血淋巴细胞微核分析，结果报道如下。     

应用细胞周期阻断法分析初诊白血病患者骨髓及外周血微核率

目的：对初诊白血病患者骨髓及外周血进行微核分析。方法：应用细胞周期阻断法对54例初诊白血病患者骨髓及外周血与30例健康人外周血淋巴细胞进行微核检测。结果：54例初诊白血病患者骨髓及外周血淋巴细胞微核率（MNR）和微核细胞率（MCR）,与30例健康人外周血相比,P〈0.01。同一患者骨髓与外周血淋巴细胞MNR和MCR相比,P〉0.05。急性淋巴细胞白血病（ALL）、急性髓细胞白血病（AML）与慢性粒细胞白血病（CML）患者骨髓及外周血淋巴细胞MNR和MCR相比,P〈0.05。结论：白血病患者发病初期即存在染色体不稳定现象,不同类型白血病患者微核检测结果间有差异,推测与白血病的发病机制密切相关。     

室内氡暴露居民外周血淋巴细胞DNA损伤及微核细胞发生率

目的：观察室内氡暴露居民外周血淋巴细胞DNA损伤及微核细胞发生率。方法：采用单核细胞凝胶电泳和微核检测两种方法。观察了我国甘肃省窑洞内氡暴露居民及对照居民外周血淋巴细胞DNA损伤及微核细胞发生率。结果：窑洞和普通住房居民（室内空气中氡浓度分别为200－350Bq.m^－3及37．5-77.1Bq.m^－3)的细胞迁移发生率分别为1．68％和1．43％，人发生细胞迁移百分别为57．1％和54．3％。50岁以上窑洞和普通住房居民细胞迁移和人发生细胞迁移率分别为2．14％、75．0％和2．00％、64．7％。窑洞和普通住房居民微核细胞发生率分别为1．07％和0．78％。结论：窑洞居民外周血淋巴细胞DNA损伤及微核细胞发生率略高于普通住房居民，P值接近0．05。     

胞浆阻滞微核测试法研究3H－TdR诱导的小剂量适应性反应

作者采用胞浆阻滞微核测试法，选用４个健康成年人静脉血，分别以３．７×１０２Ｂｑ／ｍｌ、１．４８×１０３Ｂｑ／ｍｌ３Ｈ－ＴｄＲ作为小剂量照射，３．７×１０４Ｂｑ／ｍｌ３Ｈ－ＴｄＲ和６０Ｃｏγ射线１．５Ｇｙ作为大剂量照射，结果发现先用小剂量照射，再加大剂量照射的微核率比单独大剂量照射微核率低，经统计学检验，观察值和预期值有显著性差异，表明人外周血淋巴细胞微核分析存在着小剂量辐射诱导的适应性反应现象，且个体之间有差异性，同时发现３－氨基苯胺对小剂量诱导的适应性反应有阻断作用。     

中国仓鼠细胞受照后子代微核率增加

V79中国仓鼠细胞经不同剂量X射线照射(剂量率:0.5Gy/min)后检测了①延迟接种率;②双核细胞率和微核率;③克隆间的延迟微核率和增殖死亡差异性。     

胃癌及慢性胃炎患者外周血淋巴细胞微核出现率与临床意义

对正常人及良、恶性胃疾病患者进行了微核测定。淋巴细胞微核出现率((?)±SE‰,下同)是:正常人3.40±0.26,胃癌为9.85±0.75,萎缩性胃炎为5.62±0.33,浅表性胃炎为4.86±0.23。胃癌与正常人、胃癌与两种胃炎之间均有非常显著的差异(P<0.001),两种胃炎与正常人之间均有显著差异(P<0.01),但两种胃炎之间无显著差异(P>0.05)。结果表明,胃癌患者外周血淋巴细胞微核出现率明显高于正常人和非癌胃病患者,说明该出现率反映了染色体畸变和损伤的程度。微核数随癌的恶性程度增加而增加,提示微核测定对癌的预后及复发的预测有一定意义。该方法可作为临床筛选胃癌的检测手段之一。     

民航飞行人员外周血淋巴细胞微核的观察

目的　观察宇宙辐射对民航飞行人员淋巴细胞微核的影响。　方法　采集 6 5名健康飞行人员和 2 1名地面对照人员的外周静脉血 ,在含 PHA的 RPMI16 40培养基中 37℃培养 72 h,经低渗、固定、涂片、染色 ,每例观察 10 0 0个转化淋巴细胞中的微核。　结果　飞行人员的 MNF(5 .5 1±0 .2 9‰ )、MNCF(4 .92± 0 .2 7‰ )与地面人员的 MNF(3.0 5± 0 .38‰ )、MNCF(2 .6 2± 0 .35‰ )相比 ,差异有非常显著性意义 (P<0 .0 1)。MNF、MNCF随飞行人员的年飞行小时、飞行工龄及飞行状况变化而变化的梯度小 ,差异无显著性意义 (P>0 .0 5 )。在性别和年龄可比条件下 ,吸烟飞行人员 MNF(6 .12± 0 .42‰ )、MNCF(5 .5 0± 0 .40‰ )略高于不吸烟飞行人员 MNF(5 .19± 0 .5 0‰ )、MNCF(4 .48± 0 .46‰ ) ,但差异无显著性意义 (P>0 .0 5 )。　结论　宇宙辐射引起民航飞行人员染色体损伤。常规培养微核法灵敏度低 ,不能反映飞行负荷的差别。吸烟没有明显加重飞行人员染色体损伤     

6MVX射线诱发离体人血染色体畸变剂量效应关系及与微核的比较

本文在与已报道的微核研究相同实验条件下, 观察了不同剂量(0～5Gy)照射后, 人血淋巴细胞第一次分裂时的染色体畸变, 用WHO推荐的4个模式进行了剂量效应曲线的拟台, 并选出了较优的拟合模式, 以此与CB微核法进行了比较。所得结果说明, 尽管染色体畸变的剂量效应模式可能与微核不同, 但两者的辐射敏感性是接近的。染色体畸变细胞率、总畸变、CB法微核细胞率和微核宰的加倍剂量分别是0.11、0.36、0.18和0.18Gy。     

淋巴细胞微核检测可用作辐射生物剂量计

用外周血淋巴细胞微核检测法对一起６０Ｃｏ源事故及１例非何杰金氏淋巴瘤６０Ｃｏ源全身照射治疗后的生物剂量进行了估算，取得与物理剂量或染色体剂量一致的结果。照后３１天的微核剂量仍能反映实际剂量，认为微核检测可作为生物剂量计用于估算受照者的生物剂量。在事故情况下，为尽早向临床提供剂量数据，可先观察５２小时培养制片标本，计算出初步参考剂量，然后观察７２小时培养制片的标本，给出正式剂量。     

半身照射条件下以微核估计全身等效剂量可能性的探讨

作者探讨了半身照射条件下以微核（ＭＮ）率估计相当于全身一次均匀照射剂量的可能性，并与人体模型以相同条件照射后的剂量计算结果及临床反应相验证，结果显示：以ＭＮ率所估算的剂量与人体模型所计算出的相当于一次全身均匀照射的红骨髓干细胞活存计权剂量及临床反应基本一致，照后无或仅有白细胞、血小板计数的轻微下降，多数有恶心呕吐，可能与全腹照射有关。因此，在以下半身为主的高度不均匀照射条件下，ＭＮ检测所估计的生物剂量可用以表示全身等效剂量及反映全身损伤程度。     

Use of the micronucleus assay for the selective detection of radiosensitivity in BUdR-unincorporated cells after pulse-labelling of exponentially growing tumour cells

To determine the radiosensitivity of non-S-phase tumour cells in vitro, survival curves of SCC VII tumour cells were obtained after a short block with hydroxyurea. Dose-response curves of micronucleus (MN) frequency appearing in non-S-phase cells were also determined by excluding S-phase cells with immunofluorescence staining to 5-bromo-2'-deoxyuridine (BUdR). Both the dose-response curves of MN frequency and survival curves were analysed by a linear-quadratic model (surviving fraction = exp (-alpha D-beta D2), MN frequency = aD+bD2+c). A good correlation between the alpha/beta and alpha/beta ratios was observed. In both BUdR-unincorporated and asynchronous cell cultures, the regression lines between the surviving fraction and micronucleus frequency were statistically identical. Therefore, it was shown that cell survival curves, which cannot be obtained directly by the routine colony-formation technique, can be calculated using the micronucleus frequency and the regression line in asynchronous cell cultures. Therefore, it should be possible to detect the response to irradiation of quiescent cells in tumours using the immunofluorescence staining to BUdR and the MN frequency assay.     

Intra- and inter-individual variation of background and radiation-induced micronucleus frequencies in human lymphocytes.

Serial blood samples were taken from four healthy individuals (three males, one female, aged between 26 and 51 years) in 3-monthly intervals during 1 year. Leucocyte suspensions were prepared and exposed to 3 Gy of 137Cs gamma-rays or left unirradiated as controls. In a cytokinesis-blocked (CB) micronucleus (MN) assay significant inter- and intra-donor variations of background and radiation-induced MN incidences became apparent. The two sources of variation lead to an extra variance sigma I2, in addition to the sample variance sigma e2 of MN incidences. The contributions of the different components to the total variance were estimated by means of a variance component model. The deviation sigma I for the mean background MN level of 1.53 x 10(-2) MN/CB cell was +/- 0.67 x 10(-2) and for the mean radiation-induced MN level of 0.53 MN/CB cell it was +/- 0.10. The contribution of the intra-individual variance to sigma I2 was about 50% for background MN levels and 75% for radiation-induced MN frequencies. With respect to the application of the CB-MN assay as a biological dosimetry system, the consequences of the present findings for calibration purposes and low-dose estimation are discussed. The calculation of the variance components is explained in an appendix, which serves also as an example for the adaptation of analysis of variance techniques to the evaluation of data derived from scoring of MN, as well as from scoring of metaphase chromosomal aberrations.     

A higher micronucleus yield in B-versus T-cells after low-dose gamma-irradiation is not linked with defective Ku86 protein

PURPOSE: To elaborate the B-cell micronucleus (MN) response in the low-dose region in detail and to investigate the postulated deficiency in DNA-PK in B-cells. MATERIALS AND METHODS: Lymphocytes of five healthy volunteers were irradiated with low LET gamma-rays and high LET fast neutrons with doses ranging between 0.01 and 2 Gy. After post-irradiation incubation, B- and T-cells were isolated via CD3 and CD19 immunomagnetic microbeads. MN were analysed in both subpopulations. To study the underlying mechanism of chromosomal radiosensitivity, cell extracts prepared from purified B- and T-cells were subjected to SDS-electrophoresis and electroblotting using antibodies directed against the DNA-PK repair enzymes Ku70/86 and DNA-PKcs. Activity measurements were performed using the SignaTECT DNA-dependent protein kinase assay. DNA double-strand break (DSB) induction and rejoining was determined using constant-field gel electrophoresis. RESULTS: For low LET gamma-rays a higher MN yield was observed in B-cells than in T-cells, but only in those samples exposed to doses < 1 Gy. For 1 Gy, the MN yields were comparable and for 2Gy even lower in B-cells compared with T-cells. After high LET neutron irradiation no significant differences in MN yields were observed between both subsets. The results of the DNA-PK experiments demonstrate that there is no difference between T- and B-cells in the basal expression and activity of DNA-PK repair proteins. No differences in DNA DSB induction and rejoining were found between T- and B-cells using constant-field gel electrophoresis. CONCLUSIONS: From the results, it was concluded that the enhanced chromosomal radiosensitivity in B-cells is restricted to low doses (<1 Gy) of low LET radiation and that the chromosomal behaviour of B-cells to low LET radiation cannot be attributed to aberrant forms of the DNA-PK components. A type of chromosomal induced radioresistance (IRR) may be a possible explanation for the observed effect.     

Inter-individual differences in radiation response shown by an in vitro micronucleus assay: effects of 3-aminobenzamide on X-ray treatment.

Among the methods of biological dosimetry of ionizing radiation, we propose the cytokinesis-block micronucleus assay for the measurement of the individual dose absorbed. The dose-response curve was determined for in vitro-irradiated lymphocytes from 25 individuals. The dose-response relationship, fitted by the linear-quadratic function, was F(MN) = 0.015 (+/- 0.0016) + 0.043 (+/- 0.0075).D + 0.083 (+/- 0.0045).D2. Our results are compared with those of other authors. 3-aminobenzamide (3AB) combined with X-rays were used to evaluate the micronucleus dose-response relationship in blood from 14 individuals. While it is known that 3AB inhibits poly(ADP-ribose) polymerase activity in vitro, we demonstrate that it also increases the X-ray-induced micronucleus yields. The resulting dose-response relationship varies from subject to subject. The possibility of using this approach to identify the individual radiosensitivity level is discussed.     

胞浆分裂阻滞微核法对山东"10·21"辐射事故病人受照射剂量的估算

目的 对山东"10·21"辐射事故中2例严重受照射者进行淋巴细胞微核(MN)检测,并估算受照射剂量.方法 用胞浆分裂阻滞微核(CBMN)法对2例患者(A和B)的外周血和骨髓样本分别进行MN检测.结果 2例患者的外周血培养均未见双核淋巴细胞.患者A的骨髓培养所获双核细胞极少,依据双核淋巴细胞多少粗估剂量＞20Gy.患者B的骨髓MN率为2.42个/细胞,剂量估计为8.7(8.0～9.4)Gy,与用染色体畸变分析、物理方法及ESR法所估算剂量接近,与临床表现基本一致.结论 MN法简便快速,结果准确,是除染色体畸变分析之外又一种可靠的生物剂量计.     

Automated micronucleus (MN) scoring for population triage in case of large scale radiation events

Purpose:?In case of a large-scale radiation accident when hundreds of people may be exposed, it is important to distinguish the severely exposed individuals (≥1 gray), who require early medical treatment, from those less exposed. The aim of our study was to develop a quick population triage method based on automated micronucleus (MN) scoring.

Materials and methods:?Using the MN software module developed by MetaSystems specifically for the Metafer4 platform, about 60 blood samples can be scored in one day. Standard dose response curves were determined for manual and automated MN scoring.

Results:?The automated MN assay results were closely correlated with MN yields obtained with the manual procedure. A dose of 1?Gy can be estimated with an uncertainty of 0.2?Gy. Corrections for false positives and false negatives by visual inspection of the image gallery did not result in an improved accuracy or reproducibility. To test the automated MN assay in a multicenter setting, an inter-laboratory comparison was performed whereby irradiated blood samples were processed in Ghent University (Belgium) and BfS (Bundesamt fuer Strahlenschutz; Germany). Both laboratories obtained comparable results.

Conclusions:?These results confirm the efficacy of the automated MN assay for fast population triage in a multicenter setting, in the case of large radiation accidents.     

Anabolic androgenic steroids induce micronuclei in buccal mucosa cells of bodybuilders

Objective

To evaluate genotoxicity of anabolic androgenic steroids (AAS) in male bodybuilders by a micronucleus assay in buccal mucosa cells.

Methods

11 male bodybuilders volunteered to participate in this study and two groups were formed: group 1 (n = 6), without AAS consumption and group 2 (n = 5), with AAS consumption. A sample of buccal epithelium was taken from each participant once a week for 6 weeks. Samples were fixed, stained and analysed by a light microscope, and 2000 cells were counted from each slide. Results are expressed as micronucleated cells (MNC) per 1000 cells and were analysed by the Mann–Whitney U test and Wilcoxon''s test.

Results

A marked increased in MNC was seen in bodybuilders with AAS consumption compared with those without AAS consumption (mean (SD) 4.1 (2.4) MNC/1000 cells vs 0.4 (0.4) MNC/1000 cells, respectively; p<0.004). Intragroup comparisons showed no differences in the MNC frequencies during the sampling time in group 1, whereas the MNC frequency in group 2 varied significantly, reaching the highest MNC frequencies in the third and fourth week of sampling (5.9 (2.4) MNC/1000 cells; 5.8 (1.8) MNC/1000 cells, respectively); frequency in the first sampled week was 1.1 (0.1) MNC/1000 cells. Significant differences in all sampled weeks were found between the two groups.

Conclusion

AAS consumption increased the frequency of MNC from buccal mucosa in bodybuilders.     

Comparison of micronucleus frequencies and proliferation kinetics in three X-irradiated cell lines

The kinetics of the occurrence of micronuclei was correlated with the survival of three mammalian cell lines of human, monkey, and mouse origin after irradiation with 240 kV X-rays. Particular attention was paid to the evaluation of the individual proliferation kinetics of the cell lines as well as to the characterization of micronuclei subpopulation with respect to size and possible biological importance using DNA and BUdR labelling techniques, fluorescence microscopy, and image analysis. The results demonstrate very characteristic size distributions of micronuclei for the three cell lines independent of radiation dose and time after irradiation. A close correlation between cell death and the occurrence of micronuclei (expressed as a calculated "MN index") after irradiation could be established only when the kinetics of progression of cells through the cell cycle (e.g. the doubling time) and the biological characteristics of micronuclei (e.g. BUdR positivity, the micronucleus frequencies, and the number of micronuclei per main nucleus) were taken into account. Therefore, the micronucleus assay might not be useful as a quantitative predictive assay in vivo but may allow qualitative estimations of radiation damage only because the necessary proliferation parameters of the cells might not be possible to establish in vivo.