Biomarkers of exposure using accelerator mass spectromet

这项建议的范围是开发一种新的、超灵敏的方法来定量测量人体中的DNA加合物，并研究在相当于人体暴露水平的浓度下，成人和儿童体内苯和三氯乙烯(TCE)大分子加合物的形成和修复程度。苯和三氯乙烯是工作场所的重要毒物，普遍存在于环境中。重要的是，可能对这些病原体有年龄和性别上的敏感性，这需要研究来了解对儿童构成的风险，而不是成年人。我们这个项目的目标是在动物身上开发和验证一种方法，该方法将有能力定量测量人类暴露于苯和三氯乙烯的加合物，并了解年龄和性别之间的关系，以及到达目标组织的剂量和所形成的大分子加合物的水平，这些加合物的剂量与超级基金废弃场周围遇到的剂量相同。具体来说，我们将：1.开发和验证基于加速器质谱学的同位素“后标记”分析。这种分析将涉及核苷或核苷酸的化学酰化，将是定量的，检测限将在低阿托摩尔范围内(相当于大约1个加合物/10/12个核苷酸)。这是这项技术在毒理学研究中广泛使用的继续发展。2.将这种同位素后标记-AMS分析应用于小鼠模型的初步研究，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.对苯接触工人的人类精子进行初步研究，以评估DNA加合物水平的平均水平和变异。我们将DNA加合物水平与暴露剂量、受试者年龄、血液蛋白加合物以及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.