A nonlinear isobologram model with Box-Cox transformation to both sides for chemical mixtures.
Environ Health Perspect
; 106 Suppl 6: 1367-71, 1998 Dec.
Article
em En
| MEDLINE
| ID: mdl-9860894
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.
Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Algoritmos
/
Testes de Toxicidade
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Interações Medicamentosas
Limite:
Animals
/
Humans
Idioma:
En
Revista:
Environ Health Perspect
Ano de publicação:
1998
Tipo de documento:
Article
País de afiliação:
Canadá