Department of Occupational and Environmental Health, University of Iowa, Iowa City, Iowa 52242, USA.
Appl Environ Microbiol. 2010 Aug;76(15):4988-95. doi: 10.1128/AEM.00527-10. Epub 2010 Jun 4.
As a potent inflammatory agent, endotoxin is a key analyte of interest for studies of lung ailments in domestic environments and occupational settings with organic dust. A relatively unexplored advance in endotoxin exposure assessment is the use of recombinant factor C (rFC) from the Limulus pathway in a fluorometric assay. In this study, we compared airborne endotoxin concentrations in laboratory- and field-collected parallel air samples using the kinetic Limulus amebocyte lysate (LAL) assay and the rFC assay. Air sampling was performed using paired Institute of Occupational Medicine (IOM) samplers, Button samplers, closed-face cassettes, and cyclone samplers. Field sampling was performed in 10 livestock production facilities, including those housing swine, chicken, turkey, dairy cows, cattle, and horses. Laboratory sampling was performed in exposure chambers using resuspended airborne dust collected in five livestock facilities. Paired samples were extracted in pyrogen-free water with 0.05% Tween 20 and analyzed using LAL and rFC assays. In 402 field sample pairs there was excellent agreement between endotoxin concentrations determined by LAL and rFC (r = 0.93; P < 0.0001). In 510 laboratory sample pairs there was also excellent agreement between the two assays (r = 0.86; P < 0.0001). Correlations for subgroups of facility or dust type ranged from 0.65 to 0.96. Mixed-model analysis of variance (ANOVA) for the field studies showed significant interactions of facility-sampler and facility-assay. rFC/LAL ratios of the geometric means were 0.9 to 1.14 for the samplers (not significantly different from 1.0). The data from this study demonstrate that the LAL assay and the rFC assay return similar estimates of exposure in livestock facilities. Both methods provided suitable lower limits of detection such that all but 19 of 1,824 samples were quantifiable.
作为一种强效的炎症介质，内毒素是研究室内环境和有机粉尘职业环境中肺部疾病的关键分析物。在评估内毒素暴露方面，相对较新的进展是在荧光测定法中使用来自鲎途径的重组因子 C(rFC)。在这项研究中，我们比较了使用动力学鲎变形细胞溶解物 (LAL) 测定法和 rFC 测定法对实验室和现场采集的平行空气样本中的空气中内毒素浓度。空气采样使用配对的职业医学研究所 (IOM) 采样器、纽扣采样器、封闭面盒和旋风采样器进行。现场采样在 10 个牲畜生产设施中进行，包括饲养猪、鸡、火鸡、奶牛、牛和马的设施。实验室采样在暴露室中进行，使用在五个牲畜设施中收集的再悬浮空气中的灰尘。将配对样品用无热原水提取，其中含有 0.05%吐温 20，并使用 LAL 和 rFC 测定法进行分析。在 402 对现场样本中，LAL 和 rFC 确定的内毒素浓度之间存在极好的一致性(r=0.93；P<0.0001)。在 510 对实验室样本中，两种测定法之间也存在极好的一致性(r=0.86；P<0.0001)。设施或灰尘类型亚组的相关性范围为 0.65 至 0.96。对现场研究的混合模型方差分析(ANOVA)显示设施-采样器和设施-测定法的显著交互作用。几何平均值的 rFC/LAL 比值为 0.9 至 1.14，对于采样器(与 1.0 无显著差异)。本研究的数据表明，LAL 测定法和 rFC 测定法在牲畜设施中返回相似的暴露估计值。两种方法都提供了合适的检测下限，使得 1824 个样本中只有 19 个无法量化。
