Biomarkers of exposure using accelerator mass spectromet

本提案的范围是开发一种新的和超灵敏的方法来定量测量人类DNA加合物，并研究在相当于人类暴露水平的浓度下，苯和三氯乙烯（TCE）大分子加合物在成人和儿童中的形成和修复程度。苯和三氯乙烯是工作场所的重要有毒物质，在环境中无处不在。重要的是，对这些药物可能存在年龄和性别特异性的敏感性，这需要研究以了解对儿童构成的风险，而不是对成人构成的风险。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接触苯和三氯乙烯所产生的加合物，并了解年龄和性别对到达目标组织的剂量的关系，以及在与超级基金垃圾场周围所遇到的剂量相当的剂量下形成的大分子加合物的最终水平。具体来说，我们将：1。开发和验证基于加速器质谱的同位素“后标记”分析。该分析将涉及核苷或核苷酸的化学酰化，将是定量的，并且将在低原子摩尔范围内具有检测限（相当于大约1加合物/10/12核苷酸）。这是该技术在毒理学研究中广泛应用的发展的延续。2. 将这种同位素标记后的ams分析应用于使用小鼠模型的初步研究中，以探索年龄和性别对苯和TCE DNA加合物形成和清除的影响。3. 对接触苯的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.