Laboratorium voor Analytische en Milieu Chemie, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium.
Talanta. 2011 Sep 30;85(4):1966-73. doi: 10.1016/j.talanta.2011.07.014. Epub 2011 Jul 18.
Chemical Activated LUciferase gene eXpression [CALUX] is a reporter gene mammalian cell bioassay used for detection and semi-quantitative analyses of dioxin-like compounds. CALUX dose-response curves for 2,3,7,8-tetrachlorodibenzo-p-dioxin [TCDD] are typically smooth and sigmoidal when the dose is portrayed on a logarithmic scale. Non-linear regression models are used to calibrate the CALUX response versus TCDD standards and to convert the sample response into Bioanalytical EQuivalents (BEQs). Several complications may arise in terms of statistical inference, specifically and most important is the uncertainty assessment of the predicted BEQ. This paper presents the use of linear calibration functions based on Box-Cox transformations to overcome the issue of uncertainty assessment. Main issues being addressed are (i) confidence and prediction intervals for the CALUX response, (ii) confidence and prediction intervals for the predicted BEQ-value, and (iii) detection/estimation capabilities for the sigmoid and linearized models. Statistical comparisons between different calculation methods involving inverse prediction, effective concentration ratios (ECR(20-50-80)) and slope ratio were achieved with example datasets in order to provide guidance for optimizing BEQ determinations and expand assay performance with the recombinant mouse hepatoma CALUX cell line H1L6.1c3.
化学激活荧光素酶基因表达（CALUX）是一种用于检测和半定量分析类二恶英化合物的哺乳动物细胞生物测定报告基因。当以对数标度表示剂量时，2,3,7,8-四氯二苯并对二恶英（TCDD）的 CALUX 剂量反应曲线通常是平滑的和呈 S 形的。非线性回归模型用于校准 CALUX 响应与 TCDD 标准，并将样品响应转换为生物分析等效物（BEQs）。在统计推断方面可能会出现一些并发症，特别是最重要的是对预测 BEQ 的不确定性评估。本文提出了使用基于 Box-Cox 变换的线性校准函数来克服不确定性评估的问题。正在解决的主要问题是（i）CALUX 响应的置信区间和预测区间，（ii）预测 BEQ 值的置信区间和预测区间，以及（iii）S 形和线性化模型的检测/估计能力。通过示例数据集实现了不同计算方法之间的统计比较，包括反预测、有效浓度比（ECR(20-50-80)) 和斜率比，以便为优化 BEQ 测定提供指导，并扩展重组小鼠肝癌 CALUX 细胞系 H1L6.1c3 的测定性能。
