重组缺陷型试验和几种金属化合物诱变性研究

本文用重组修复阳性枯草杆菌H_(17)(Rec~+)和重组修复缺陷型枯草杆菌M_(45)(Rec~-)及其胞子,进行了胞子和生长茵的灵敏度比较,有或没有代谢活化剂的胞子重组试验。结果表明,枯草杆菌胞子比生长茵敏感7～10倍,该法能检测需要或不需要代谢活化的化学物质和金属化合物的诱变性。     

果蝇 DNA 修复试验评价膳食纤维对诱变剂毒性的作用

本次研究应用果蝇 DNA 修复试验检测膳食纤维对诱变剂的吸附作用与提高用各种诱变剂处理的 DNA 修复缺陷的幼蝇存活率是否密切相关。实验结果表明,10种受试的纤维中,爱兰苔胶和木质素可明显减少3-氨基-1-甲基-5-氢-吡啶吲哚(Trp-P-2)对果蝇的致死性,而其余纤维如果胶、精氨酸和来自大豆的中性净化纤维均无作用。培养基中用 Trp-P-2和纤维处理的 DNA 修复缺陷雄幼蝇的死亡率与培养基中的游离 Trp-P-2的水平呈负相关。上述实验结果提示,膳食纤维可吸附 Trp-P-2,减少 Trp-     

冷培养对金属化合物枯草杆菌致变试验结果的影响

目的：研究枯草杆菌芽孢重组修得试验中增加冷培养对金属化合物和间接致变物DNA损伤试验的影响。方法：比较直接培养法与增加4℃ 24h冷培养对测试结果的作用。观察指标：最小抑菌浓度（MIC）和敏感性。结果：增加冷培养对大多数金属化合物测试结果无影响，而对K2Cr2O4、CoCl2、CoSO4及2种间接致突变物2-AF、AFB反而提高了MIC，降低了敏感性。此结果与Kada的报道不尽一致，对其原因加以探讨。结论：枯草杆菌芽孢重组修复试验增加冷培养，降低了部分金属致突变物和间接致变物敏感性。     

金属化合物的重组缺陷型试验和诱变性研究

金属化合物的遗传毒性研究比较少。大约30年前,Demerec和他的同事报道某些铁、锰和汞的化合物在细菌中可引起点突变。Nishi-oka指出,重组缺陷型试验阳性金属化合物中,重铬酸钾、钼酸铵和亚砷酸钠是诱变剂。细菌重组缺陷型试验也证实砷、铬和硒化合物具有诱变性。作者对127种金属化合物,用重组缺陷型试验和回变试验进行诱变性检测。重组缺陷型试验用枯草杆菌H17(Rec~+arg~-try~-)和M45(Rec~-,arg~-try~-)菌株。在加金属化合物后和37℃培养之前进行“冷培养”,即培养皿在4℃保存24小时,这样延长了金属化合物和非正在     

465株结核分枝杆菌药物敏感试验二种方法比较

目的：应用绝对浓度法和比例法对４６５例结核分枝杆菌作药物敏感试验比较研究。方法：采用绝对浓度法和比例法检测４６５株结核分枝杆菌对四种抗结核药物（ＩＮＨ、ＳＭ、ＲＦＰ、ＥＭＢ）的敏感性。结果：４６５株结核分枝杆菌四种抗结核药物总耐药率分别为１８．５％和２０．９％,无显著性差异（ｐ〈０．０５）。两种药敏测定法符合率为９５．３％～９７．８％。结论：绝对浓度法和比例法对结核分枝杆菌药物敏感试验无显著性差异,两种方法目前均可在实际工作中应用。     

石棉诱发人外周血淋巴细胞姐妹染色单体交换分析

目前普遍认为,姐妹染色单体交换(SCE)是染色体损害和修复的指标。业已证实SCE是揭示化学诱变剂和致癌物质对染色体作用的极为敏感的指标。1974年,Late研究丝裂霉素C对人的淋巴细胞作用时,发现低得不能使染色体畸变增高的浓度,仍可使SCE有明显的增高,从此SCE的方法被建议用于监测诱变剂对哺乳类染色体的作用。由于SCE的计数容易,正确,观察染色体畸变敏感,它要求的诱变剂的浓度远远低于引起染色体畸变的浓度,且发生率高,观察的细胞数较少,故近年来     

不同梅毒螺旋体基因重组抗原酶联免疫试验比较

目的 对单一梅毒螺旋体（Treponema palidum,Tp）基因重组抗原Tp47、Tp42或TP17及联合3种基因重组抗原（Tp47、Tp42和Tp17）酶联免疫试验（enzyme immunoassay,EIA）进行比较。方法 分别用3种单一Tp基因重组抗原Tp47、Tp42或Tp17EIA法，检测11份梅毒血凝试验Tp抗体阳性和28份阴性血清，并与联合应用3种基因重组抗原（Tp47、Tp42和Tp17）EIA法比较。结果 单一基因重组抗原Tp47、Tp42和Tp17EIA法的灵敏工分别为100％（11／11）、100％（11／11）和90．9％（10／11）特异度分别为96．4％（27／28）、100％（28／28）和96．4％（27／28）；联合应用3种基因重组抗原EIA法的灵敏度和特异度分别为100％（11／11）和100％（28／28）。结论 单一Tp基因重组缺的EIA法用于梅毒诊断存在一定的假阳性和假阴性反应，联合应用3种基因重组抗原（Tp47、Tp42和Tp17）EIA法的灵敏度高于单一Tp基因重组抗原EIA法。     

小儿肺炎细菌学检测及药敏试验

目的 了解小儿肺炎的细菌病原谱及药敏情况。方法 采用气管内导管法取声门以下部位分泌物培养，阳性者再作药敏试验。结果 细菌检出阳性率为20.8%,其中肺炎克雷伯氏菌最多，其次为大肠埃希菌、流感嗜血杆菌，不动杆菌，阴沟肠肝菌等。对头孢噻肟，菌必治，复达欣、泰能，氟哌酸，环丙沙星敏感率最高。结论 小儿肺炎病原菌以革兰氏阴性菌多见，抗菌素以头孢三代为敏感。     

枯草杆菌重组修复试验在环境致突变剂研究中的应用

为了有效地检出环境中的致突变剂和致癌剂,作者建立了枯草杆菌重组修复试验方法。方法原理是据根遗传性DNA重组修复能力缺陷型菌株M_(45)在受到DNA损伤剂作用时较野生型菌株H_(17)易受抑制和死亡。因此通过检测被检化学物对两菌株抑菌效应的差别,就能判明是否有DNA损伤。重组修复试验的阳性结果只表示DNA损伤,要结合其他的生物检测方法,以确定DNA损伤剂的致突变特性。     

用培养法测定广州地区120例健康成人外周血的微核正常值

微核测定是染色体损伤的快速测定方法,目前广泛用于诱变剂的检测。人外周血淋巴细胞微核培养法测定,因其取材于人体,且操作简单,对各种诱变剂反应较浓集法敏感,故有广阔的应用前景。但由于国内各地正常值范围报道不一。因此,我们于1989年进行了此项工作。     

Synthesis and estrogenic activity of bisphenol a mono- and di-beta-D-glucopyranosides, plant metabolites of bisphenol A

The syntheses and characterization of bisphenol A mono- and di-beta-D-glucopyranosides were undertaken to confirm that these compounds are major plant metabolities of bisphenol A (BPA) and to allow an assessment of their estrogenicity. Synthesis involved the glucosidation of unprotected BPA with glucose penta-acetate with phosphorus oxychloride as catalyst. The estrogenic activity of BPA and its mono- and di-beta-D-glucopyranosides were measured with an enzyme-linked immunosorbent assay (ELISA)-based estrogen receptor competitive binding assay and with a yeast two-hybrid assay adapted to a chemiluminescent reporter gene (for beta-galactosidase). Both methods showed that the estrogenicity of BPA was eliminated by formation of the di-glucoside, but whereas the ELISA-based method indicated that reduced activity remained in the monoglucoside, the yeast two-hybrid method showed the monoglucoside to be inactive. Presumably these results reflect the more complex interactions of test compound and cellular components required to demonstrate estrogenicity in the yeast two-hybrid assay. As these processes parallel those in mammalian cells, the yeast two-hybrid method is likely to be the more realistic assay. The uptake and metabolism of BPA by plants offers the possibility of phytoremediation of contaminated water, but also provides an additional route for the compound to enter the human food chain.     

Selection and evaluation of the immunogenicity of protective antigen mutants as anthrax vaccine candidates

Protective antigen (PA) is a central component of anthrax toxin and a major antigen in anthrax vaccines. However, the use of native PA as a vaccine is not optimal. If administered to people who have been freshly exposed to anthrax, PA may actually aid in anthrax toxin formation and thus may pose a serious safety concern for postexposure vaccination applications. A non-functional PA mutant may be a much safer alternative. To identify an improved anthrax vaccine antigen, we examined four non-functional mutants of PA, each being impaired in a critical step of the cellular intoxication pathway of PA. These mutants were Rec(-) (unable to bind PA-receptors), SSSR (resistant to activation by furin), Oligo(-) (unable to form oligomers), and DNI (Dominant Negative Inhibitory, unable to form endosomal transmembrane pores). When tested in mice and after three doses of immunization, all four mutants were highly potent in eliciting PA-specific, toxin-neutralizing antibodies, with immunogenicity increasing in the order of PA相似文献   

多不饱和脂肪酸在骨质疏松症中的研究进展

多不饱和脂肪酸（PUFA）,是指碳氢链有两个或两个以上不饱和键的脂肪酸,通常分为n-3PUFA和n-6PUFA两种。骨质疏松症（OP）是以骨量减少、骨组织显微结构退化为特征,以致骨的脆性增高及骨折危险性增加的一种全身性骨病。已知遗传、年龄、内分泌、饮食等因素均参与OP的发病,但确切的病因及发病机制尚未明了。近年不少研究发现饮食中的PUFA对骨健康存在重要影响,本文特就PUFA在OP发病机制及治疗中的研究进展作一综述。     

蝎形引物PCR快速检测环境水样中沙门菌方法研究

[目的]以蝎形引物PCR技术为基础建立一套环境水样沙门菌的快速检测方法。[方法]选择沙门菌himA基因设计出以荧光素(FAM)和淬灭物(DABCYL)双标记探针的茎环尾状结构构成蝎形引物，对8种沙门菌和8种非沙门菌经增菌、DNA提取后，以蝎形引物PCR方法进行检测，探讨该检测方法的可行性、特异性和灵敏度，并与普通引物PCR法检测50份环境水样进行比较。[结果]蝎形引物PCR方法检测沙门菌，细菌密度与荧光相对强度存在着量比关系，与普通引物PCR法比较，具有快速、特异、灵敏度高的特点，在50μl PCR及反应体系中最低可检出2cfu沙门菌。[结论]沙门菌蝎形引物在PCR扩增中，探针可特异地与目的DNA片段杂交，使DABCYL不能有效地淬灭FAM产生的荧光，荧光可经仪器直读检出。所建立的快速检测方法可定性或定量的用于环境水样中沙门菌检测。     

A commentary on some inconsistencies in the icrp 2005 recommendations: exclusion levels

The International Commission on Radiological Protection (ICRP) 2005 Recommendations, which were released at the International Radiation Protection Association's congress held in Madrid (May 2004), have been available for public comment via the ICRP's Web site. The comment period has now closed and the Recommendations are presumably being re-worked. There are several inconsistencies in the Recommendations and they are exemplified by looking at the exclusion levels in more detail. The relevant text of the Recommendations is included in this paper as an . It is suggested that the International Atomic Energy Agency's approach is more balanced where each nuclide receives its own exclusion level instead of the incomplete and arbitrary categories proposed by the ICRP.     

细胞毒试验对香烟毒性检测的研究

目的通过体外细胞毒试验研究快速检测香烟综合毒性的技术。方法采用细胞毒试验(中性红法),选用仓鼠肺细胞(V79)与受试物作用,经处理、培养和仪器测试判定待检样品是否对细胞有毒性作用。结果在各不同时间段可以看出,不同浓度组香烟提取物(CSE)对细胞毒性作用的强弱不同,显色变化明显。低毒香烟组显色浅,半数抑制浓度(IC50)值大,细胞毒性小;高毒香烟组显色深,IC50值小,细胞毒性大。结论香烟的综合毒性越强,细胞毒试验显色越明显,反之亦然,证实细胞毒试验可作为快速检测香烟综合毒性的初筛方法。     

食品中肠出血性大肠埃希菌O157:H7的PCR检测

目的建立快速准确检测食品中肠出血性大肠埃希菌O157：H7的方法。方法采用多重聚合酶链式反应技术（MPCR）特异性扩增肠出血性大肠埃希菌O157：H7的STX、rfbE、fliC基因。结果分别在228，378，709bp处扩增出3个目的基因片段，且只有肠出血性大肠埃希菌O157：H7获得扩增，其他菌种扩增均呈阴性。结论PCR方法比传统细菌检测方法更特异、快速、灵敏和简便，为食品中肠出血性大肠埃希菌O157：H7的快速检测提供了新的手段。     

水体污染中常见致病菌的多重PCR分子检测研究

[目的]建立同时检测沙门氏菌、志贺氏菌、绿脓杆菌、肠出血型大肠杆菌和副溶血弧菌等5种水体常见致病菌的多重PCR检测技术,为这些致病菌感染的快速诊断提供实验依据。[方法]筛选设计5对特异引物,建立优化的多重PCR扩增体系和条件。[结果]对5种致病菌的检测,多重PCR灵敏度分别为：肠出血型大肠杆菌O157102 cfu、志贺氏菌102 cfu、副溶血弧菌102 cfu、绿脓杆菌101 cfu、沙门氏菌102 cfu。应用于人工污染水样及天然水样的检测,均有清晰、特异的预期条带产生,并与传统检测结果一致,每个样品所需时间为6～8 h,相对于传统检测方法,极大地缩短了检测时间,提高了检测灵敏度。[结论]该方法适用于大通量样品的检测研究,可推广应用于食品检测、环境监测等领域。     

Neutralizing antibody but not hemagglutination antibody provides accurate evaluation for protective immune response to H5N1 avian influenza virus in vaccinated rabbits

In order to develop an animal model and an assay method to evaluate protective immune response to H5N1 avian influenza vaccination, H5N1 avian influenza vaccine was prepared. New Zealand rabbits were assigned to receive two doses of vaccine with different hemagglutinin (HA) dosage. The sera from vaccinated rabbits was evaluated to determine antibody titer and specificity using different tested methods including hemagglutination inhibition assay (HI), neutralizing assay (NT), cross-HI assay, cross-single immunodiffusion assay and cross-neutralization assay. The titer of HI antibody from rabbits immunized with different doses of HA were no less than 1:40 among groups 14 days after the first immunization. Whereas the NT antibody titer was less than 1:10 among groups 14 days after the first immunization. NT antibodies can be detected 14 days after the second immunization in rabbits immunized at HA doses higher than 6 μg, and the NT antibody titers were equal to or higher than 1:40. A good concentration-dependent NT antibody response can be detected in the vaccinated rabbits 14 days after the second immunization, and in contrast, no concentration-dependent relationship can be seen for HA antibody. The cross-HI test showed sera from vaccinated rabbits could cross react with influenza A H5N1 virus with the titers higher than 1:40. No cross reaction among different types (influenza A/H1N1 virus, influenza A/H3N2 virus, influenza B virus and influenza A/H5N1 virus) can be detected in the sera using the single immunodiffusion assay and using NT antibody test. This showed NT antibody test was demonstrated as a more accurate assay method for evaluating vaccination and quality of the vaccine than HI antibody test.     

乳胶粒子法检测甲胎蛋白的应用

目的:评价Latex法检测甲胎蛋白(AFP)的临床应用价值。方法:对血清标本做批内批间重复性测定试验及La-tex法与电化学发光法进行对比测定。结果:Latex法与电化学发光法检测AFP结果无显著差异,Latex法与电化学发光法平均回收率分别为95.5%和96.7%。结论:电化学发光法灵敏度、精密度高,但其仪器、试剂价格高,不适于全面推广;Latex法与电化学发光法检测AFP结果无显著差异,相关性好,快速、结果稳定,试剂便宜在全自动生化仪上检测,可广泛应用。