Biomarkers of exposure using accelerator mass spectromet

本提案的范围是开发一种新的超灵敏方法，用于定量测量人体中的DNA加合物，并研究苯和三氯乙烯（TCE）大分子加合物在成人和儿童中形成和修复的程度，其浓度相当于人体暴露水平。苯和三氯乙烯是工作场所的重要有毒物质，在环境中普遍存在。 重要的是，对这些药剂可能存在特定年龄和性别的敏感性，这需要进行研究，以了解对儿童而不是成人构成的风险。本项目的目标是开发和验证一种动物方法，该方法将有能力定量测量人类接触苯和三氯乙烯的加合物，并了解年龄和性别对到达靶组织的剂量的关系，以及在相当于超级基金废物场地周围遇到的剂量下形成的大分子加合物的水平。具体来说，我们将：1。开发并验证基于加速器质谱的同位素“后标记”分析。该测定将涉及核苷或核苷酸的化学酰化，将是定量的，并且将具有低阿托摩尔范围内的检测限（相当于约1个加合物/10/12个核苷酸）。这是该技术在毒理学研究中广泛使用的发展的延续。2.应用这种同位素后标记-AMS测定在试点研究中使用小鼠模型，以探索年龄和性别对苯和TCE DNA加合物的形成和清除的影响。3.对苯接触工人的精子进行初步研究，以评估DNA加合物水平的平均水平和变化。我们将把DNA加合物水平与暴露剂量、受试者年龄、血液蛋白加合物和本项目中其他项目测量的染色体损伤标记物相关联。

The scope of this proposal is to develop a novel and ultra sensitive method for the measurement of DNA adducts quantitatively in humans and to study the degree of benzene and trichloroethylene (TCE) macromolecular adduct formation and repair in adults and children at concentrations equivalent yo human exposure levels. Benzene and TCE are important toxicants in the workplace and are ubiquitous in the environment. Importantly, there may be age- and gender-specific sensitivity to these agents, which requires study to understand the risks posed to children as opposed to adults. Our goal for this project is to develop and validate a method in animals that will have the capacity to quantitatively measure adducts from benzene and TCE exposure in humans and to understand the relationship between age and gender on the dose reaching the target tissues and the resultant levels of macromolecular adducts that are formed at doses equivalent to those encountered around superfund waste sites. Specifically, we will: 1. Develop and validate an accelerator mass spectroscopy-based isotope "post-labeling" assay. This assay will involve chemical acylation of nucleosides or nucleotides, will be quantitative, and will have detection limits in the low attomole range (equivalent to approximately 1 adducts/10/12 nucleotides). This is a continuation of the development of this technology for broad use in toxicology research. 2. Apply this isotope post-labeling-AMS assay in pilot studies using a mouse model to explore age and gender effects on benzene and TCE DNA adduct formation and clearance. 3. Conduct a pilot study with human sperm from benzene exposed workers to assess the mean level and variation in DNA adduct levels. We will correlate DNA adduct levels with exposure dose, subject age, blood protein adducts, and markers of chromosomal damage measured by other projects in this program.