人外周血网织红细胞微核作为辐射生物剂量仪的初步研究

背景与目的:探讨人外周血网织红细胞微核率是否可以替代双核淋巴细胞微核率作为辐射生物剂量仪.材料与方法:以接受放疗的鼻咽癌(nasopharyngeal cancer,NPC)患者为受辐照模型,以双核淋巴细胞微核实验为比对标准,应用已建立的基于单激光流式细胞仪的人外周血网织红细胞微核自动化检测体系,检测NPC患者接受不同累积放疗剂量后的外周血网织红细胞微核率.结果:NPC患者接受放疗后,外周血网织红细胞微核率迅速显著增高,呈现良好的剂量-反应关系;外周血网织红细胞微核率对辐射的反应模式与双核淋巴细胞微核率对辐射的反应模式一样,所得曲线方程均符合Y=A BX-CX2 DX3模式.结论:人外周血网织红细胞微核率有可能替代双核淋巴细胞微核率作为辐射生物剂量仪对辐射所致损伤进行评估.     

吡虫啉和抑食肼对人体外周血淋巴细胞遗传物质的影响

目的: 研究两种新型杀虫剂-吡虫啉和抑食肼对人体外周血淋巴细胞遗传物质的影响.方法:人体外周血淋巴细胞的微核试验,姐妹染色单体互换试验(SCE)以及单细胞凝胶电泳试验(SCGE,又名彗星试验).结果:在低浓度(吡虫啉为0.05 mg/L,抑食肼为5 mg/L)时,它们对微核和SCE的影响与对照组相比无显著性差异(P>0.05),当浓度升高(吡虫啉为0.1 mg/L,抑食肼为25 mg/L)时,则有显著性差异(P<0.05).而彗星试验在各试验组与对照组相比都有极显著性差异(P<{0.01}),且存在明显的剂量-效应关系(r=0.995, r=0.965).结论:吡虫啉和抑食肼对人外周血淋巴细胞的遗传物质都具有一定程度的损伤作用,相比之下,吡虫啉比抑食肼具有更大的毒性.     

1,2-二甲基-3-羟基-4-吡啶酮遗传毒性的研究

背景与目的:研究1,2-二甲基-3-羟基-4-吡啶酮(DHPO)的急性毒性及不同剂量、不同时间的遗传毒性.材料与方法:采用昆明种小鼠,先进行LD50试验,然后对高(1/2 LD50)、中(1/4 LD50)、低(1/8 LD50)DHPO剂量组进行外周血和骨髓微核率的观察.结果:DHPO的小鼠经口LD50为562.34 mg/kg.外周血和骨髓微核试验显示,1/8 LD50(70 mg/kg)组、1/4 LD50(140 mg/kg)组微核率与阴性对照组相比差异均无统计学意义(P＞0.05);1/2 LD50(280 mg/kg)组微核率高于阴性对照组、1/8 LD50(140 mg/kg)组和1/4 LD50组(P均＜0.05).结论:DHPO属于低毒药物,具有小鼠体内染色体畸变的遗传毒性.     

海藻多糖对γ-射线诱发的小鼠微核形成率的影响

目的: 观察海藻多糖(PS)的抗辐射效应.方法:观察PS对60Coγ-射线诱发的小鼠外周血淋巴细胞及骨髓嗜多染红细胞微核率的影响.结果:小鼠接受2 Gyγ-射线照射后,外周血淋巴细胞及骨髓嗜多染红细胞微核率明显升高(P＜0.01);20 mg/kg*bw及40mg/kg*bw剂量的PS能使照射小鼠外周血淋巴细胞微核率明显降低(P<0.05); 10 mg/kg*bw、20 mg/kg*bw及40 mg/kg*bw剂量的PS能使照射小鼠骨髓嗜多染红细胞微核率明显降低(P＜0.05).结论:PS对γ-射线诱发的染色体损伤有明显的保护作用.     

煤焦沥青对作业工外周血淋巴细胞DNA的损伤

背景与目的:了解煤焦沥青接触工人外周血淋巴细胞DNA损伤情况.材料与方法:应用外周血淋巴细胞单细胞凝胶电泳(SCGE)试验及微核(MN)试验,分别检测43名煤焦沥青接触工人和21名对照工人外周血淋巴细胞DNA损伤情况.结果:接触组外周血淋巴细胞中彗星出现率及微核发生率分别为(3.26±1.12)×10-2和(1.23±0.27)×10-3,高于对照组,且这种损伤效应可随接触时间的延长而增强.结论:长期接触煤焦沥青可明显地导致作业工外周血淋巴细胞DNA损伤.     

7种农药对植物及人外周淋巴细胞SCE影响的比较观察

目的：研究杀虫磺、杀虫双、杀虫环、杀菌剂NF133、蚓哚乙酸、久效磷和氧化乐果7种农药对人和植物细胞染色体的诱变性,并比较其诱变作用在人和植物上是否一致。方法：测定蚕豆、大麦根尖细胞和人外周血淋巴细胞姐妹染色单体交换（SCE）率。结果：7种农药都能明显诱导蚕豆、大麦根尖细胞和人外周血淋巴细胞和SCE率增加。结论：本研究中7种农药对植物和人细胞均有较强的作用。对植物细胞与对人细胞的诱变作用是一致的。     

三氯乙烯对职业人群的细胞遗传学效应

目的 :探讨三氯乙烯(TCE)对职业人群有无细胞遗传损伤作用以及与接触浓度和时间的关系。 方法 :采用气相色谱和吡啶化学比色法对工作场所中TCE浓度和工人尿中三氯乙酸(TCA)含量进行了测定 ,采用外周血淋巴细胞微核试验、胞质分裂阻滞微核试验以及姐妹染色单体交换(SCE)试验、单细胞凝胶电泳(SCGE)试验对141名直接接触TCE的工人和39名对照者检测了有无染色体损伤和DNA损伤。 结果 :TCE接触组人群(车间内空气中TCE平均浓度为90.4mg/m3 ,尿中TCA平均浓度为61.79mg/L)微核、双核微核、SCE和彗星样淋巴细胞出现率分别为1.66‰、2.73‰、4.33、7.48 % ,均明显高于对照组(分别为1.13‰、1.66‰、2.95、3.74 % ,P<0.05或P<0.01) ;除SCE外 ,微核、双核微核、彗星样淋巴细胞出现率与接触工龄间存在相关关系(r=0.222 ,0.246 ,0.320 ;P<0.05或P<0.01) ;微核、双核微核发生率、SCE和彗星样淋巴细胞出现率与尿中TCA浓度间也存在相关关系(r=0.294 ,0.260 ,0.229 ,0.268 ;P<0.05或P<0.01)。 结论 :TCE具有遗传毒作用 ,长期接触高浓度TCE可导致染色体断裂和DNA损伤     

肺癌患者外周血淋巴细胞微核、SCE和染色体畸变的研究

 本文分析观察14例肺癌患者和14例正常健康人外周血淋巴细胞的微核, SCE和染色体畸变。 结果发现肺癌患者的微核率、SCE频率和染色体畸变率均高于正常对照组。 经统计学分析表明两组之间差异显著, 认为染色体不稳定可能是肺癌发生的物质基础。     

重质芳烃的致突变性研究

目的：用Ames试验,小鼠骨髓嗜多染红细胞微核试验,人体外周血淋巴细胞姐妹染色单体交换（SCE）试验以及小鼠精子畸形试验对重质芳烃进行了致突变性研究,结果：重质芳烃无移码突变和碱基置换效应,微核试验显示在316－1580mg/kg.bw剂量范围小鼠骨髓嗜多染红细胞微核率显著增加（与阴性对照组比较P＜0．01）;SCE试验结果显示在活化系统（S9混合液）存在的条件下,人外周血淋巴细胞SCE频率较对照组显著增高（在0．5mg/ml及5mg/ml剂量组）;小鼠精子畸形试验显示在1580m,g/kg.bw剂量水平小鼠精子畸形率显著增高,与阴性对照组比较差异有显著性（P＜0．01）,结论：重质芳烃具有间接致突变性,对其职业性接触及应用的安全性应给予,高度重视。     

吲哚-3-甲醇诱导人鼻咽癌细胞凋亡作用及机制的初步研究

背景与目的： 了解吲哚-3-甲醇在体外对人鼻咽癌CNE细胞增殖的影响及其诱导CNE细胞凋亡的作用及其可能机制。 材料与方法： 采用WST-1法检测吲哚-3-甲醇在体外对人鼻咽癌CNE细胞增殖的抑制作用;用Hochest33258荧光染色法及TUNEL法观察吲哚-3-甲醇诱导CNE细胞的凋亡;用Western blotting方法检测凋亡相关信号分caspase-9、caspase-3蛋白表达情况,实验同时设空白对照组及溶剂对照组。 结果： 吲哚-3-甲醇在体外可以明显抑制人鼻咽癌细胞增殖,诱导细胞凋亡并呈剂量依赖性,且在细胞凋亡过程中,半胱天冬酶家族成员caspase-9和caspase-3 活化片段表达阳性。 结论： 吲哚-3-甲醇在体外可抑制人鼻咽癌CNE细胞增殖并诱导其发生凋亡,且凋亡的发生可能与caspase-9、caspase-3活化有关。     

靶向HRP/IAA自杀基因系统联合IL-12基因治疗Lewis肺癌的研究

目的:观察人端粒酶逆转录酶(hTERT)启动子驱动辣根过氧化物酶(HRP)/吲哚乙酸(IAA)系统联合白细胞介素-12(IL-12)基因对小鼠Lewis肺癌的疗效。方法:建立Lewis肺癌移植瘤模型,随机分为对照组、HRP组、IL-12组和联合组,分别给予AdCMVGFP、AdhTERTHRP、AdCMVmIL-12单一或联合注射,然后腹腔注射IAA,观察肿瘤生长情况。蛋白质印迹法和ELISA检测瘤组织HRP和IL-12表达;免疫组化检测瘤组织内CD4+、CD8+淋巴细胞浸润情况。结果:与对照组、单一治疗组相比,联合组小鼠肿瘤生长受到显著抑制(联合组vs对照组:P=0.000,9 d;联合组vsHRP组:P=0.005,15 d;联合组vsIL-12组:P=0.046,12 d),生存期显著延长(联合组vs对照组:χ2=9.529,P=0.002;联合组vsHRP组:χ2=9.039,P=0.003;联合组vsIL-12组:χ2=8.595,P=0.003),肿瘤组织广泛坏死,CD4+、CD8+淋巴细胞浸润显著增多。结论:IL-12基因治疗可诱导宿主产生抗肿瘤免疫应答,与靶向HRP/IAA自杀基因系统联合具有...     

Analysis of the horseradish peroxidase/indole-3-acetic acid combination in a three-dimensional tumor model

Horseradish peroxidase has previously been shown to catalyze the conversion of indole-3-acetic acid (IAA) to a potent cytotoxin in a gene therapy setting. A three-dimensional spheroid model composed of a human head and neck carcinoma cell line, has been used to mimic the tumor microenvironment, such as regions of hypoxia. Exposure of intact spheroids to 0.05-5 mM concentrations of IAA and the halogenated indole, 5-bromoindole-3-acetic acid (5Br-IAA), resulted in decreased cell survival, and demonstrates that this combination is effective under tumor-simulated conditions. In addition, 5Br-IAA, displayed selectivity for spheroids with a large hypoxic fraction following short exposure times.     

Cytogenetic Finding of Breast Cancer Cases and in Their First-Degree Relatives

Purpose

The aim of this study was to evaluate and compare the rate of sister chromatid exchange (SCE), the occurrence of micronuclei, and the lymphocyte proliferation rate index (PRI) in patients with breast cancer, their first-degree relatives, and healthy volunteers.

Methods

We analyzed the frequency of SCE and micronuclei, and the PRI in the peripheral blood lymphocytes of 30 women with breast cancer, 22 of their female family members, and 20 age-matched healthy female volunteers.

Results

SCE occurred significantly more often in the lymphocytes of breast cancer patients (10.84±0.4 per metaphase), compared with their first-degree relatives (7.45±0.54) and controls (5.94±0.2) (p<0.001 for both). The mean SCE frequency was not statistically different between first-degree relatives and controls (p=0.071). Similarly, micronuclei occurred at a significantly higher rate in breast cancer patients (9.6±0.72), and in their first-degree relatives (7±0.64), compared to controls (3.85±0.4) (p<0.001 and p=0.001, respectively). There was also a significant difference between the occurrence of micronuclei in patients compared to their family members (p=0.021). The PRI was significantly lower in patients (1.61±0.1), compared with both their first-degree relatives (1.75±0.1), and controls (1.74±0.1) (p=0.001 and p=0.002, respectively).

Conclusion

Increased SCE and the occurrence of micronuclei, as well as a reduced PRI are associated with breast cancer. Furthermore, increased SCE and the frequency of micronuclei in a first-degree relative suggest that they exhibit greater genetic instability than women of the same age.     

Increased Sister Chromatid Exchange in Peripheral Blood Lymphocytes from Humans Exposed to Pesticide: Evidence Based on a Meta-analysis

Background: Sister chromatid exchange (SCE) in human peripheral blood lymphocytes is one of the mostextensively studied biomarkers employed to evaluate genetic damage subsequent to pesticide exposure. Objective:To estimate the pooled levels of SCE in human peripheral blood lymphocytes among population exposed topesticide. Materials and Methods: Meta-analysis on the association between SCE frequency and pesticide exposurewas performed with STATA 10.0 software package and Review Manager 5.0.24 in this study. Results: The overallmeans of SCE were 7.88 [95% confidence intervals (95%CI): 6.71-9.04] for exposure group and 6.05 (95%CI:5.13-6.95) for controls, respectively. There was statistically significant difference in the SCE frequency in humanperipheral blood lymphocytes between pesticide-exposed groups and control groups, and the summary estimateof weighted mean difference was 1.69 (95%CI: 1.01-2.38). We also observed that pesticide-exposed populationhad significantly higher SCE frequency than control groups among smokers, nonsmokers, pesticide applicator,pesticide producer, other exposure population and Asian population in stratified analyses. Conclusions: Dataindicate that the SCE frequency in human peripheral blood lymphocytes might be an indicator of early geneticesffects for pesticide-exposed populations.     

Genotoxic activity of plant growth-regulating hormones in Aspergillus nidulans

Three plant growth-regulating hormones, indole-3-acetic acid(IAA), indole-3-butyric acid (IBA), and kinetin (6-furfuryl-aminopurine),were tested for their genetic activity in Asper-gillus nidulansin a plate test. The first two hormones were found to greatlyincrease somatic segregation in the fungus whereas kinetin wasnot effective. Several concentrations of the plant hormoneswere used and it was found that increasing concentrations ofIAA and IBA increased mitotic segregation of the fungus withmost of the segregants being produced by mitotic crossing-over,together with non-disjunctional segregants at a lower level.The metabolic activation technique was also used and it wasshown that when S9 mixture was added to IAA and IBA a further3- to 5-fold increase in the number of segregants was obtained.In the case of kinetin the S9 had no effect.     

Development of a novel enzyme/prodrug combination for gene therapy of cancer: horseradish peroxidase/indole-3-acetic acid

This paper demonstrates the potential for utilizing the plant enzyme, horseradish peroxidase (HRP), in a gene-directed enzyme prodrug therapy context. Human T24 bladder carcinoma cells transfected with a mammalian expression vector containing the HRP cDNA were selectively sensitized to the nontoxic plant hormone, indole-3-acetic acid (IAA). The HRP/IAA-induced cell kill was effective in normoxic and anoxic conditions. The activated drug is a long-lived species able to cross cell membranes, and cell contact appears not to be required for a bystander effect to take place. These preliminary results suggest that the delivery of the HRP gene to human tumors followed by IAA treatment may provide a novel cancer gene-directed enzyme prodrug therapy approach, with potential to target hypoxic cells.     

人端粒酶逆转录酶启动子在裸鼠中增强人喉癌对基因放射治疗的敏感性

目的 探索人端粒酶逆转录酶启动子(hTERTp)介导自杀基因辣根过氧化酶(HRP)-吲哚乙酸(IAA)系统联合射线,对相同来源而放射敏感性不同的人喉癌移植瘤模型的治疗作用.方法 建立相同来源而放射敏感性不同的人喉癌(Hep-2和Hep-2R细胞)移植瘤模型,并分为联合治疗组(A组和AR组)、基因治疗组(B组和BR组)、单纯放射组(C组和CR组)和对照组(D组和DR组).瘤内注射脂质体包裹的质粒phTERTp-HRP,腹腔内注射IAA从并联合放疗30 Gy,观察对移植瘤生长的抑制作用.应用原位末端转移酶标记技术(TUNEL)检测肿瘤细胞的凋亡情况;应用AP法检测瘤内HRP蛋白的表达.结果 裸鼠移植瘤生长以联合治疗组最慢,以对照组最快.A组的肿瘤抑制率为54.8%,B组为10.0%,C组为31.9%,AR组为52.7%,BR组为24.8%,CR组为17.0%.A组和AR组可见大量肿瘤细胞坏死和凋亡,凋亡指数分别为16.6%±1.3%和17.6%±1.3%,高于其他组(P<0.05).B组的HRP蛋白表达率(21.9%±5.7%)低于BR组和(33.3%±8.9%),辐射诱导后,A组和AR组的HRP蛋白表达率分别增加2.1和1.6倍(P<0.05).结论 在不同放射敏感性的喉癌移植瘤模型中,hTERTp能被射线诱导,并根据瘤内端粒酶活性增强HRP基因的表达.hTERTp·HRP-IAA系统通过诱导肿瘤细胞凋亡和引起细胞坏死,抑制裸鼠移植瘤生长,并与射线协同作用,起到放射增敏作用.     

Sister chromatid exchange induction in human lymphocytes exposed to benzene and its metabolites in vitro

Previous in vivo studies have shown that low-dose benzene exposure (10 to 28 ppm for 4 to 6 h) in mice can induce sister chromatid exchange (SCE) in peripheral blood B-lymphocytes and bone marrow as well as micronuclei in bone marrow polychromatic erythrocytes. Because benzene is metabolized to a variety of intermediate compounds and two of these, catechol and hydroquinone, have been reported to be potent SCE-inducers, it is possible that other known and proposed metabolites could have chromosome-damaging effects in lymphocytes. Induced SCE frequencies, mitotic indices, and cell cycle kinetics were quantitated in human peripheral blood T-lymphocytes exposed to benzene, phenol, catechol, 1,2,4-benzenetriol, hydroquinone, 1,4-benzoquinone, or trans,trans-muconic acid. Three proposed metabolites of phenol, 4,4'-biphenol, 4,4'-diphenoquinone, and 2,2'-biphenol, which can be generated by a phenol-horseradish peroxidase-hydrogen peroxide system were also examined. Benzene, phenol, catechol, 1,2,4-benzenetriol, hydroquinone, and 1,4-benzoquinone induced significant concentration-related increases in the SCE frequency, decreases in mitotic indices, and inhibition of cell cycle kinetics. Based on the slope of the linear regression curves for SCE induction, the relative potencies were as follows: catechol greater than 1,4-benzoquinone greater than hydroquinone greater than 1,2,4-benzenetriol greater than phenol greater than benzene. On an induced SCE per microM basis, catechol was approximately 221 times more active than benzene at the highest concentrations studied. trans,trans-Muconic acid had no significant effect on the cytogenetic parameters analyzed. 2,2'-Biphenol induced a significant increase in SCE only at the highest concentration analyzed, and 4,4'-biphenol caused a significant increase in SCE frequency that was not clearly concentration related. However, both 2,2'- and 4,4'-biphenol caused significant cell cycle delay and mitotic inhibition. 4,4'-Diphenoquinone caused only a significant decrease in mitotic activity. These data indicate that in addition to phenol, di- and trihydroxybenzene metabolites play important roles in SCE induction. Furthermore, the results suggest either that benzene alone can induce SCE or, a more likely possibility, that mononuclear leucocytes have a limited capability to activate benzene.