鱼微核试验筛检水体诱变物的应用与研究

对五种试验污染物的遗传毒性采用鱼微核试验技术进行了筛检,试验结果表明鱼微核试验用作筛检诱变物的遗传毒性有效的,对监测水体的质量也具有潜在的价值;同时,对国内外学将各种各样的技术应用到鱼微核式试验进行了总结,概述了微核形成的机理;在此基础上,提出应用鱼微核试验筛检水体诱变物时应注意的问题。     

从文献计量分析看京津冀近65年昆虫学研究发展态势

本文运用文献计量学方法,对新中国成立以来发表在我国主要中文期刊上的京津冀地区昆虫学文献进行检索、整理、分类、统计和分析,共搜集了2457篇相关文献。探讨了这些文献的文献学特征,包括数量年度分布、研究类群分布、研究领域分布、文献载体分布、研究机构分布和学科方向分布,并对昆虫学各分支学科的发展情况进行了阶段分析,以期了解该地区昆虫学研究发展的基本现状和趋势。     

中国陆生脊椎动物野外调查的发展现状与文献分析

新中国成立以来,我国已开展了大量陆生脊椎动物的本底调查和多样性研究项目,取得了一系列成果,并有学者针对兽类、鸟类和两栖爬行类的野外调查监测进行了总结和展望,但尚缺乏对所有陆生脊椎动物类群的调查历史和现状的分析及基于文献收集的研究,特别是对调查方法和技术手段的对比与总结。因此,本文通过文献收集的方法,基于中国知网、Web of Science核心合集和以图书检索为主的读秀学术搜索,以“兽类”“鸟类”“爬行类”“两栖类”“动物资源”“调查”“监测”“新种”“新记录”和“物种多样性”作为检索词,检索并筛选了与兽类、鸟类、爬行类及两栖类陆生脊椎动物调查相关的文献资料共3,504篇,对陆生脊椎动物调查的研究文献在全国各省级行政区、生物多样性热点地区的分布,及其运用的调查方法和技术手段进行了系统的分析和比较。结果表明:相较兽类和两栖爬行类的调查,我国鸟类多样性的调查最多,发表文献占所有文献的70.26%。四川、云南的陆生脊椎动物调查最多,分别发表285篇、260篇文献。分布于我国的4个全球生物多样性热点地区的调查强度存在显著差异,印缅生物多样性热点地区和中国西南山地的研究文献较多,分别为348篇、...     

运用蚕豆根尖细胞微核试验分析校园水体的污染

许多研究表明 ,饮用水及生活污水中存在具有致突性的有机化学物质 ,其水源污染主要来源于生活污染源、工业污染源以及微生物生长活动引起非活性化学物转化成致突物等 ,在这些致突物中 ,许多具有遗传毒性。目前 ,研究饮用水的遗传毒性可用许多短期遗传毒性试验 ,其中蚕豆根尖细胞微核试验作为致突性分析的一种测试系统已越来越受到人们的青睐和应用。1　蚕豆根尖微核试验原理环境污染物 (如物理、化学、生物污染源 )能诱发植物细胞的染色体畸变 ,染色体断片游离在细胞质中于分裂末期形成微核。蚕豆是对污染物较为敏感的植物品种 ,利用污染过…     

太湖蓝藻滤液的遗传毒性研究

蓝藻爆发是环境污染引发的重要事件之一,随之产生的蓝藻毒素又直接危及区域水安全.该论文采用蚕豆和大蒜根尖微核试验研究了太湖蓝藻暴发期间蓝藻滤液的遗传毒性.结果表明,同阴性对照相比,所有试验处理对蚕豆根尖细胞微核发生率的影响显著增加;对大蒜根尖细胞微核发生率而言除蓝藻滤液8倍稀释液的影响不显著外,其它水平效应显著高于阴性对照,而且表现出一定的剂量效应.暴发期蓝藻滤液原液对蚕豆根尖细胞微核发生率影响显著高于阳性对照(0.8mg·mL^-1环磷酰胺)的效应,从而说明蓝藻暴发时期蓝藻滤液具有较强的遗传毒性.通过微核试验效果分析,蚕豆作为植物监测系统的敏感性和稳定性都优于大蒜材料.     

口腔微生态失衡导致口腔异昧的研究

目的介绍口腔微生态失调与口腔疾病的关系,口腔疾病出现口腔气味异常的机制。综合分析口腔微生态与口腔健康的研究动态及意义。展望口腔微生态调整在口腔疾病治疗中的作用研究,尤其在消除口腔异昧的积极作用。方法由第一、二作者应用计算机通过pubmed检索NCBI数据库1992年至2007年相关文献,检索词为“Micro ecology”,限定语言种类为“English”;同时检索CNKI全文数据库、维普全文数据库1995年至2007年相关文献,检索词为“微生态”,限定语言种类为中文。纳入标准：文章内容与口腔微生态相关的研究、以及在口腔疾病研究领域有关。排除标准：较陈旧的文献和重复研究。结果共收集到106篇相关文献,21篇文献纳入本文,其中,19篇为综述和述评类文献,19篇为中文杂志,2篇为外文杂志。结论致病菌大量生长繁殖,口腔微生态失调,菌斑内微生物之间以及机体与菌斑之间相互作用分解蛋白产生硫化物,这些代谢产物包括H2S、CH3SH、CH3SCH3、吲哚、甲基吲哚、挥发脂肪酸和聚胺等发出刺激性气味,产生口腔异味。治疗口腔异味应该考虑平衡口腔微生态,调整口腔菌群。口腔异味的治疗又有利于口腔菌群平衡。提示我们治疗口腔疾病应该考虑口腔微生态平衡。     

口腔微生态失衡导致口腔异味的研究

目的介绍口腔微生态失调与口腔疾病的关系,口腔疾病出现口腔气味异常的机制。综合分析口腔微生态与口腔健康的研究动态及意义。展望口腔微生态调整在口腔疾病治疗中的作用研究,尤其在消除口腔异昧的积极作用。方法由第一、二作者应用计算机通过pubmed检索NCBI数据库1992年至2007年相关文献,检索词为“Micro ecology”,限定语言种类为“English”;同时检索CNKI全文数据库、维普全文数据库1995年至2007年相关文献,检索词为“微生态”,限定语言种类为中文。纳入标准：文章内容与口腔微生态相关的研究、以及在口腔疾病研究领域有关。排除标准：较陈旧的文献和重复研究。结果共收集到106篇相关文献,21篇文献纳入本文,其中,19篇为综述和述评类文献,19篇为中文杂志,2篇为外文杂志。结论致病菌大量生长繁殖,口腔微生态失调,菌斑内微生物之间以及机体与菌斑之间相互作用分解蛋白产生硫化物,这些代谢产物包括H2S、CH3SH、CH3SCH3、吲哚、甲基吲哚、挥发脂肪酸和聚胺等发出刺激性气味,产生口腔异味。治疗口腔异味应该考虑平衡口腔微生态,调整口腔菌群。口腔异味的治疗又有利于口腔菌群平衡。提示我们治疗口腔疾病应该考虑口腔微生态平衡。     

家庭食物可及性与儿童肥胖的定性循证研究

目的：检索国内外文献,综合分析家庭食物环境与儿童肥胖的关系,为儿童肥胖的预防和治疗提供依据。方法：维普数据库、万方数据库、中国期刊网、Pubmed、Medline、Cochrane Library检索1998—2020年国内外公开发表的（国内限核心期刊）的相关研究文献,语种限定为中文和英文。结果：共检索出文献144 篇,共纳入8篇文献作为本研究的主要证据,综合评价家庭食物环境与儿童肥胖的关系。家庭食物环境包括家庭食物可及性、家庭共餐情况、家庭成员营养素养等。塑造健康的家庭食物环境有益于儿童青少年形成健康的饮食习惯、维系合理体重。结论：良好的家庭食物环境有利于塑造儿童健康的饮食行为,但对儿童体重和肥胖发生率的影响尚缺乏足够的证据。     

基于Web of Science数据库扩张型心肌病研究的文献计量学分析

目的:对扩张型心肌病(Dilated Cardiomyopathy,DCM)的研究,目前仍是国际上对于原发性心肌病研究的热点问题。本文针对DCM相关领域的研究文献进行计量分析,从而进一步深入了解国际DCM研究进展,为该研究的相关领域提供参考。方法:基于(SCIE)引文数据库为检索对象,检索2003-2012年DCM的所有相关文献,分别对不同国家和地区、著者、机构、文献来源期刊及论文学科分布等进行统计分析。结果:共检索出DCM研究文献12728篇,研究论文发表共涉及了107个国家和地区,美国的发文数最多4500篇,占35.36%,其次为德国和日本。中国居第9位,504篇占总发文量的3.96%;主要刊登期刊涵盖了国际上心血管领域的15种知名期刊;研究热点涉及心血管系统及脏病学、分子生物学、基因遗传学等学科。结论:目前DCM研究仍是人们关注的一个热点,美国、德国、日本等发达国家在该领域的研究居领先水平,中国在这一领域也做出了贡献。与领先国家和机构相比,我国亟需进一步加强对DCM的研究。为我国进一步了解和深入研究DCM的方向提出参考。     

国外急诊专科医师胜任力框架及其应用概述

目的 对国外急诊专科医师胜任力要求及其应用进行比较分析,为我国开展急诊专科医师胜任力研究提供参考。方法 以美国、欧洲、加拿大和澳大利亚为研究对象,运用文献研究法检索国外相关机构官方网站和外文数据库,收集和分析各国急诊专科医师胜任力相关文献。结果 经过检索,共获得相关资料和文献1 740余篇,初筛后纳入文献136篇,复筛后最终纳入文献24篇。结论 胜任力研究已逐渐成为各国开展急诊专科医师培养的基础和关键,研究对于规范我国急诊医师培养和考核具有较强的借鉴意义。     

Chromosomal mutagen sensitivity associated with mutations in BRCA genes

Chromosomal mutagen sensitivity is a common feature of cells from patients with different kinds of cancer. A portion of breast cancer patients also shows an elevated sensitivity to the induction of chromosome damage in cells exposed to ionizing radiation or chemical mutagens. Segregation analysis in families of patients with breast cancer indicated heritability of mutagen sensitivity. It has therefore been suggested that mutations in low-penetrance genes which are possibly involved in DNA repair predispose a substantial portion of breast cancer patients. Chromosomal mutagen sensitivity has been determined with the G2 chromosome aberration test and the G(0) micronucleus test (MNT). However, there seems to be no clear correlation between the results from the two tests, indicating that the inherited defect leading to enhanced G(0) sensitivity is different from that causing G2 sensitivity. Less than 5% of breast cancer patients have a familial form of the disease due to inherited mutations in the breast cancer susceptibility genes BRCA1 or BRCA2. Heterozygous mutations in BRCA1 or BRCA2 in lymphocytes from women with familial breast cancer are also associated with mutagen sensitivity. Differentiation between mutation carriers and controls seems to be much better with the MNT than with the G2 assay. Mutagen sensitivity was detected with the MNT not only after irradiation but also after treatment with chemical mutagens including various cytostatics. The enhanced formation of micronuclei after exposure of lymphocytes to these substances suggests that different DNA repair pathways are affected by a BRCA1 mutation in accordance with the proposed central role of BRCA1 in maintaining genomic integrity. Mutations in BRCA1 and BRCA2 seem to predispose cells to an increased risk of mutagenesis and transformation after exposure to radiation or cytostatics. This raises a question about potentially increased risks by mammography and cancer therapy in women carrying a mutation in one of the BRCA genes. Lymphoblastoid cell lines (LCLs) from breast cancer patients have been used to study the mechanisms and genetic changes associated with tumorigenesis. With respect to mutagen sensitivity, conflicting results have been reported. In particular enhanced induction of micronuclei does not seem to be a general feature of LCLs with a BRCA1 mutation in contrast to lymphocytes with the same mutation. Therefore, LCLs are of limited utility for studying the mechanisms underlying chromosomal mutagen sensitivity.     

Chemically induced micronucleus formation in V79 cells--comparison of three different test approaches

The in vitro micronucleus test (MNT) is a useful assay for the detection of mutagenic events on both the chromosomal and the genomic level. The main disadvantage for introducing the in vitro MNT into official test guidelines seems to be the disparity of existing protocols. To contribute to the aim of standardisation, three different methodological approaches of the in vitro MNT with V79 cells were compared: the standard assay using an asynchronically growing mixed cell population, the cytokinesis block (CB) assay and a modified MNT, the so-called mitotic shake-off (MSO) method. V79 cells were thus treated with two known aneugens (colcemide and griseofulvin) and two clastogens (mitomycin C and cyclophosphamide) over various time periods. The cultures of the CB assay were additionally exposed to cytochalasin B (Cyt-B), an inhibitor of cell, but not of nucleus division. After treatment, the cells were harvested and analysed for the appearance of micronuclei (MN). All three assays yielded positive results for all test substances. These results support the suitability of the MNT with V79 cells with regard to the ability to detect the genotoxic potential of both clastogens and aneugens independent of the test protocol applied. Thus, all three methods are appropriate for MN detection, but due to the fact that the application of Cyt-B has no advantages for a cell line like V79 in which nearly all cells undergo a normal cell cycle, its use is not recommended.     

Investigating micronucleus assay applicability for prediction of normal tissue intrinsic radiosensitivity in gynecological cancer patients

BackgroundPelvic organs morbidity after irradiation of cancer patients remains a major problem although new technologies have been developed and implemented. A relatively simple and suitable method for routine clinical practice is needed for preliminary assessment of normal tissue intrinsic radiosensitivity. The micronucleus test (MNT) determines the frequency of the radiation induced micronuclei (MN) in peripheral blood lymphocytes, which could serve as an indicator of intrinsic cell radiosensitivity.AimTo investigate a possible use of the micronucleus test (MNT) for acute radiation morbidity prediction in gynecological cancer patients.Materials and methodsForty gynecological cancer patients received 50 Gy conventional external pelvic irradiation after radical surgery. A four-field “box” technique was applied with 2D planning. The control group included 10 healthy females.Acute normal tissue reactions were graded according to NCI CTCAE v.3.0. From all reaction scores, the highest score named “summarized clinical radiosensitivity” was selected for a statistical analysis.MNT was performed before and after in vitro irradiation with 1.5 Gy. The mean radiation induced frequency of micronuclei per 1000 binucleated cells (MN/1000) and lymphocytes containing micronuclei per 1000 binucleated cells (cells with MN/1000) were evaluated for both patients and controls.An arbitrary cut off value was created to pick up a radiosensitive individual: the mean value of spontaneous frequency of cells with MN/1000 ± 2SD, found in the control group.ResultsBoth mean spontaneous frequency of cells with MN/1000 and MN/1000 were registered to be significantly higher in cancer patients compared to the control group (t = 2.46, p = 0.02 and t = 2.51, p = 0.02). No statistical difference was registered when comparing radiation induced MN frequencies between those groups.Eighty percent (32) of patients developed grade 2 summarized clinical radiosensitivity, with great variations in MNT parameters. Only three patients with grade 2 “summarized clinical radiosensitivity” had values of cells with MN/1000 above the chosen radiosensitivity threshold.ConclusionThe present study was not able to confirm in vitro MNT applicability for radiosensitivity prediction in pelvic irradiation.     

Kinetochore immunofluorescence in micronuclei: a rapid method for the in situ detection of aneuploidy and chromosome breakage in human fibroblasts

We have developed a rapid and simple immunodetection assay for the in situ identification of aneuploidy in mitotic fibroblasts. Kinetochore (centromere)-containing micronuclei can be detected easily and rapidly by immunofluorescence. The action of colchicine and its derivatives on the mitotic spindle apparatus of mammalian cells induces chromosome lag and aneuploidy. The treatment of normal human fibroblasts with Colcemid resulted in increased levels of micronuclei. Using an immunofluorescence stain (scleroderma CREST antiserum, biotinylated goat antihuman IgG and streptavidin-Texas Red) to detect the presence of kinetochores, it was observed that 90% of the Colcemid-induced micronuclei contained one or more fluorescent bodies (kinetochores). Cultured skin fibroblasts from a patient with ataxia telangiectasia (AT), which is a chromosome breakage syndrome, were used as a control. The AT fibroblasts exhibited elevated levels of spontaneous micronuclei when compared with normal fibroblasts, and 85% of these micronuclei were kinetochore-negative. This finding supports the hypothesis that the majority of spontaneous micronuclei in AT cells arise from chromosome breakage. The spontaneous micronucleus frequencies for 8 strains of human fibroblasts were in the order of 0.5-2%. Spontaneous levels of kinetochore-positive micronuclei were measured for these 8 strains; in 5 of the strains, about 25% of the micronuclei were kinetochore-positive, and in the other 3 strains approximately 50% of the micronuclei were kinetochore-positive. These data suggest that genetic factors may play a role in the control of the spontaneous levels of chromosome breakage and/or segregation errors which result in aneuploidy.     

Enhancement of micronuclei frequency in the Tradescantia/micronuclei test using a long recovery time

The Tradescantia/micronuclei test (TRAD/MCN) is a well-validated test for monitoring environmental genotoxicants. These pollutants induce at the early meiotic stage of pollen mother cells chromosome fragments which become micronuclei at the tetrad stage. The standard test protocol requires some hours of exposure of the inflorescences and a recovery time of about 24 hours to reach the early tetrad stage. Since the recovery period represents a critical step of the TRAD/MCN, experiments were performed to establish its length in plants of clone #4430 of the hybrid T. hirsutiflora x T. subacaulis which is widely used in environmental monitoring. The aim of the present research was to ascertain the exact duration of recovery time in order to improve the sensitivity of the TRAD/MCN test. First, studies were performed to select the flowers at the beginning of the meiosis, and then anthers were sampled and studied for a period of 48-86 hours. The complete meiosis in the plants examined required about 80 hours. Second, exposure to genotoxic substances followed by different recovery times was carried out to demonstrate that effectiveness of the TRAD/MCN test is closely related to the duration of the recovery time. The test was carried out by exposing inflorescences to known mutagens (sodium azide and maleic hydrazide) for six hours followed by different recovery times (24-72 hours). The results showed that the frequency of micronuclei in the pollen mother cells increased with the length of the recovery time.     

中国出生缺陷遗传学研究的回顾与展望

减少出生缺陷是我国“健康中国2030”规划中的重要组成部分。遗传因素单独或协同作用导致了超过80%的出生缺陷疾病。与出生缺陷相关的遗传学研究可为临床筛查、诊断和治疗提供精准的分子靶标。我国的出生缺陷遗传学研究自20世纪60年代以来取得了长足的发展。同时,随着相关研究成果的不断涌现,以遗传咨询和检测为核心的临床转化工作也在不断深化和完善。基础研究与临床应用的紧密结合,将为我国孕育“健康孩”提供可靠的技术保障。本文首先回顾了我国出生缺陷遗传学研究的历史,继而介绍当前国内外出生缺陷遗传学研究的现状和热点,最后对未来的研究方向及相关的临床应用趋势进行展望和讨论,旨在为读者提供了一个全局性的视角来认知我国的出生缺陷遗传学研究发展之路。     

Inhibition of acrylamide genotoxicity in human liver-derived HepG2 cells by the antioxidant hydroxytyrosol

The chemoprotective effect of hydroxytyrosol (HT), a strong antioxidant compound from extra virgin olive oil, against acrylamide (AA)-induced genotoxicity was investigated in a human hepatoma cell line, HepG2. The micronucleus test (MNT) assay was used to monitor genotoxicity. In MNT, we found that HT at all tested concentrations (12.5-50 microM) significantly reduced the micronuclei frequencies in a concentration-dependent manner caused by AA. In order to clarify the underlying mechanisms we measured the intracellular reactive oxygen species (ROS) formation using 2,7-dichlorofluorescein diacetate (DCFH-DA) as a fluorescent probe. Intracellular glutathione (GSH) level was estimated by fluorometric methods. The rate-limiting enzyme in GSH synthesis is gamma-glutamylcysteine synthetase (gamma-GCS) and gamma-GCS was measured using Western blotting. The results showed that HT significantly concentration-dependent reduced the genotoxicity caused by AA. Furthermore, HT was able to reduce intracellular ROS formation and attenuate GSH depletion caused by AA in a concentration-dependent manner. It was also found that HT enhanced the expression of gamma-GCS in HepG2 cells treated with 10 mM AA using immunoblotting in a concentration-dependent manner. The results showed that HT reduced the AA-induced genotoxicity by decreasing the ROS level and increasing the GSH level. The data strongly suggest that HT have significant protective ability against AA-induced genotoxicity in vitro.     

Genotoxic effect and nitrative DNA damage in HepG2 cells exposed to aristolochic acid

Aristolochic acid (AA), extensively used as a traditional herbal medicine, was withdrawn from the market in the last century because it was found to be a potent carcinogen in humans and animals. The aim of this study was to evaluate the genotoxic effect of AA and obtain further insight into whether the nitrative DNA damage can be induced by reactive nitrogen species (RNS), including nitric oxide (NO) and its derivative peroxynitrite (ONOO(-)) using human hepatoma HepG2 cells. To identify the genotoxic effect, the comet assay and micronucleus test (MNT) were performed. In the comet assay, 25-200microM of AA caused a significant increase of DNA migration in a dose-dependent manner. A significant increase of the frequency of micronuclei was found in the range between 12.5 and 50microM in the MNT. The results showed that AA caused DNA and chromosome damages. To elucidate the nitrative DNA damage mechanism, the level of nitrite and 8-hydroxydeoxyguanosine (8-OHdG), which can be generated by ONOO(-), were monitored with the 2,3-diaminonaphthalene (DAN) assay and immunoperoxidase staining, respectively. The results showed that AA causes a significant increase in the levels of NO and formation of 8-OHdG at concentrations >/=50microM. This observation supports the assumption that AA could exert genotoxicity probably via NO and its derivatives at higher concentrations in HepG2 cells.     

Sudan I induces genotoxic effects and oxidative DNA damage in HepG2 cells

Sudan I, a synthetic lipid soluble azo pigment, is widely used in various industrial fields. However, Sudan I has not been approved at any level of food production, since there are many inconclusive reports relating to its genotoxicity and carcinogenicity in humans. The aim of this study was to assess the genotoxic effects of Sudan I and to identify and clarify the reaction mechanisms by use of human hepatoma HepG2 cells. To study the genotoxic effects of Sudan I, the comet assay and micronucleus test (MNT) were used. In the comet assay and MNT, we found increase of DNA migration and of the micronuclei frequencies at all tested concentrations (25-100 microM) of Sudan I in a dose-dependent manner. The data suggest that Sudan I caused DNA strand breaks and chromosome breaks. To elucidate the underlying mechanism of this difference, we monitored the level of reactive oxygen species (ROS) production with the 2,7-dichlorofluorescein diacetate assay. The level of the oxidative DNA damage and lipid peroxidation was evaluated using immunoperoxidase staining for 8-hydroxydeoxyguanosine (8-OHdG) and by measuring levels of thiobarbituric acid-reactive substances (TBARS). Significantly increased levels of ROS, 8-OHdG and TBARS were observed in HepG2 cells at higher concentrations, the doses being 100, 50-100 and 50-100 microM, respectively. We conclude that Sudan I causes genotoxic effects, probably via ROS-induced oxidative DNA damage at the higher doses.     

Investigations on the mutagenicity of 1,4-dichlorobenzene and its main metabolite 2,5-dichlorophenol in vivo and in vitro

The genotoxic potential of 1,4-dichlorobenzene (1,4-DCB) has been extensively evaluated in vitro and in vivo. The majority of the studies demonstrated the absence of a genotoxic potential for 1,4-DCB. At variance are a bone marrow micronucleus test (MNT) after intraperitoneal (i.p.) treatment of NMRI mice [Mohtashamipur et al., Mutagenesis 2 (1987) 111–113] and a gene mutation assay on mouse lymphoma cells [McGregor et al., Environ. Mol. Mutagen. 12 (1988) 85–145]. Therefore, we investigated 1,4-DCB and its main metabolite 2,5-dichlorophenol (2,5-DCP) for both endpoints. In an MNT, male and female NMRI mice were treated orally with single doses of 2500 mg/kg 1,4-DCB and 1500 mg/kg 2,5-DCP, respectively. Smears were prepared 24, 48 and 72 h thereafter. No induction of micronuclei was detected for both compounds. Also under the conditions of Mohtashamipur et al. (1987), intraperitoneal treatments of male and female mice with 2 × 177.5 and 2 × 355 mg/kg 1,4-DCB failed to induce micronuclei. In addition, CHO/HPRT-gene mutation tests with 1,4-DCB and 2,5-DCP yielded negative results for both compounds with and without metabolic activation system. Therefore, 1,4-DCB and 2,5-DCP are considered to be non-mutagenic in these test systems.