title: The ratios of individual chemicals in a mixture determine the degree of joint effect: the climax hypothesis.
abstract: A new hypothesis, the Climax Hypothesis, is proposed to describe how the ratios of individual chemicals influence the joint effects of chemical mixtures. This hypothesis is derived from a generalized approach using "isobolograms". With this hypothesis, one can predict that for a given mixture, a curvilinear correlation exists between the joint effects and the ratios of individual chemicals and that this curve has a climax at the equitoxic ratio. This prediction is supported by the observed toxicity to Vibrio fischeri of 18 mixtures (12 binary mixtures, 4 ternary mixtures, and 2 quaternary mixtures). With this prediction, the Climax Hypothesis has some promising applications such as controlling the discharge of effluents in environmental science, maximizing detoxifying effects in medicine, and optimizing combined pesticides in agriculture.
authors.affiliation: Key Laboratory of Tropical Marine Environmental Dynamics, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, People's Republic of China. lzhifen@yahoo.com
authors.forename: Z
authors.initials: Z
authors.lastname: Lin
authors.forename: Z
authors.initials: Z
authors.lastname: Ping
authors.forename: D
authors.initials: D
authors.lastname: Kong
authors.forename: K
authors.initials: K
authors.lastname: Yin
authors.forename: Z
authors.initials: Z
authors.lastname: Cai
mesh_terms: D003627:Data Interpretation, Statistical; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004781:Environmental Exposure / Q000009:adverse effects*; D008163:Luminescent Measurements; D008962:Models, Theoretical; D018675:Toxicity Tests / Q000379:methods; D014733:Vibrio / Q000187:drug effects / Q000254:growth & development; D014874:Water Pollutants, Chemical / Q000633:toxicity; D015262:Xenobiotics / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical; D015262:Xenobiotics