PLEURAL DOSIMETRY AND BIOMARKERS OF RESPONSE TO FIBERS

职业性接触石棉纤维与 风险发展间皮瘤，恶性肿瘤引起的胸膜 或腹膜衬里。 过去石棉的广泛使用 公众关注环境暴露也可能产生间皮瘤。 评估接触后发生恶性间皮瘤的风险 石棉或其他纤维是困难的，因为最小剂量的纤维 产生这些肿瘤所需的条件是未知的。 目前的啮齿动物模型 间皮瘤是不令人满意的，因为他们使用极高剂量的 通过腹膜内或胸膜内注射直接递送纤维 而不是吸入。 拟议研究的目的是 建立一种新的动物模型，以确定生物有效剂量 青石棉石棉纤维所需的启动发展， 间皮瘤 纤维剂量测定将表示为 纤维存款并持续存在于胸膜内层， 消化，透射电子显微镜，和视频增强 微分干涉对比光学显微镜观察纤维， 潜在的靶细胞群（特定目标#1）。 两个答案 潜在的靶细胞将被验证为特异性和敏感性生物制剂， 对沉积在胸膜中的石棉纤维的反应标记。 第一、 石棉纤维引起的染色体损伤的分子标记将被 使用生物素标记的DNA探针和原位杂交。 鼠标 着丝粒DNA探针将用于检测染色体非整倍性， 结构畸变 抑癌基因p53杂合性缺失 基因位点将通过中期的间接免疫荧光显示 扩散和间期核（具体目标#2）。 第二，量化 将开发间皮细胞损伤和增殖的标志物 使用形态测定法（特定目标#3）。 纤维剂量测定和生物标记物 将比较胸膜内注射后的反应， 吸入青石棉纤维。 这些实验将评估 是否存在沉积在纤维中的纤维数量之间的相关性 胸膜，它们的持续性，以及种群倍增次数 在恶性间皮瘤的组织学表现之前（特定目的 #4和5）。 最终，这个新模型可以用来推断 人体接触石棉和人造石棉的剂量-反应关系 矿物纤维，以更准确地评估发展的风险 恶性间皮瘤

Occupational exposure to asbestos fibers is associated with an increased risk of developing mesotheliomas, malignant tumors arising from the pleural or peritoneal linings. Widespread use of asbestos in the past raises public concern that environmental exposure may also produce mesotheliomas. Assessment of the risk of developing malignant mesothelioma after exposure to asbestos or other fibers is difficult because the minimum dose of fibers required to produce these tumors is unknown. Current rodent models of mesothelioma are unsatisfactory because they use extremely high doses of fibers delivered directly by intraperitoneal or intrapleural injection instead of inhalation. The objective of the proposed research is to develop a new animal model to determine the biologic effective dose of crocidolite asbestos fibers required to initiate the development of mesotheliomas. Fiber dosimetry will be expressed as the total number of fibers that deposit and persist in the pleural lining using tissue digestion, transmission electron microscopy, and video-enhanced differential interference contrast light microscopy to visualize fibers in potential target cell populations (Specific Aim #1). Two responses of potential target cells will be validated as specific and sensitive biologic markers of response to asbestos fibers deposited in the pleura. First, molecular markers for chromosomal damage induced by asbestos fibers will be developed using biotinylated DNA probes and in-situ hybridization. A mouse centromeric DNA probe will be used to detect chromosomal aneuploidy and structural aberrations. Loss of heterozygosity at the p53 tumor suppressor gene locus will be visualized by indirect immunofluorescence on metaphase spreads and interphase nuclei (Specific Aim #2). Second, quantitative markers of mesothelial cell injury and proliferation will be developed using morphometry (Specific Aim #3). Fiber dosimetry and biologic markers of response will be compared following intrapleural injection and inhalation of crocidolite asbestos fibers. These experiments will assess whether there is a correlation between the number of fibers deposited in the pleura, their persistence, and the number of population doubling times before the histologic appearance of malignant mesothelioma (Specific Aims #4 and 5). Ultimately, this new model could be used to extrapolate dose-response relationships to human exposure to asbestos and man-made mineral fibers in order to assess more accurately the risk of developing malignant mesotheliomas.