Work

A nonlinear isobologram model with Box-Cox transformation to both sides for chemical mixtures.

Year: 1998

Type: article

Abstract: The linear logistical isobologram is a commonly used and powerful graphical and statistical tool for analyzing the combined effects of simple chemical mixtures. In this paper a nonlinear isobologram model is proposed to analyze the joint action of chemical mixtures for quantitative dose-response relationships. This nonlinear isobologram model incorporates two additional new parameters, Ymin and Ymax, to facilitate analysis of response data that are not constrained between 0 and 1, where parameters Ymin and Ymax represent the minimal and the maximal observed toxic response. This nonlinear isobologram model for binary mixtures can be expressed as [formula: see text] In addition, a Box-Cox transformation to both sides is introduced to improve the goodness of fit and to provide a more robust model for achieving homogeneity and normality of the residuals. Finally, a confidence band is proposed for selected isobols, e.g., the median effective dose, to facilitate graphical and statistical analysis of the isobologram. The versatility of this approach is demonstrated using published data describing the toxicity of the binary mixtures of citrinin and ochratoxin as well as a new experimental data from our laboratory for mixtures of mercury and cadmium.

Source: Environmental Health Perspectives

DOI: 10.1289/ehp.98106s61367

Authors: D G Chen, J G Pounds

Institution: Fisheries and Oceans Canada

Language: English

Topic: Environmental Toxicology and Ecotoxicology

Subfield: Health, Toxicology and Mutagenesis

Field: Environmental Science

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $4,500

Funder: National Center for Complementary and Integrative Health