Additive or synergistic interactions

Collectively, valerian extracts show a variety of GABAergic mechanisms. The predominant mechanism has yet to be determined, but an additive or synergistic interaction among the several mechanisms is Dossible. Future research on valerian extracts needs to address any compositional differences Detween aqueous and nonaqueous extracts, and to determine the responsible active constitutents. 

As an example of what 10-6 would mean in terms of the U.S. population, a total of 20 cases of cancer would result if 10 of the population was exposed at a dose level equivalent to a 10-6 risk for 70 years. That would be one-third of a cancer case per year as an upper limit in the U.S. population compared with the approximately 500,000 annual cancer deaths that occur. The actual number of cases attributable to that particular substance would probably be less, and perhaps none at all would occur unless some additive or synergistic interaction with other substances resulted in enhanced toxicity. 

In brief, the PEEP index is a useful HAS to apply in comparative studies of wastewater effluents to assess their ecotoxicity and toxic loading. Some of its advantages include the fact that it considers results from different toxicity tests and endpoints, while integrating all possible antagonistic, additive or synergistic interactions that can occur between toxicants in a complex liquid sample. Furthermore, the use of a single PEEP value becomes very useful for decisionmakers who are then able to take science-based decisions to prioritize corrective actions on industries whose effluents are the most toxic for the aquatic environment. It is also noteworthy to point out that the PEEP index can be applied anywhere with any number or type of tests and endpoints to suit the needs and expertise of laboratories internationally. 

Soy protein isolate shows an additive or synergistic interaction with potassium that may be successfully exploited to design gel products with desired characteristics. To this end the response surface methodology proved to be an excellent tool. 

The extent of the risk with these serotonergic drugs is not known, but because of the potential severity of the reaction this warning would seem to be a prudent precaution. For more information on the serotonin syndrome, see Additive or synergistic interactions , (p.9). 

The serotonin syndrome seems to occur rarely but patients and prescrib-ers should be aware of the symptoms so that prompt action can be taken if problems occur. For more about the serotonin syndrome see, Additive or synergistic interactions , (p.9). 

Assessing the effects of pollutants on aquatic ecosystems is complicated by the fact that trace contaminants generally appear as mixtures, often as complex suites of trace metals and organics. This is particularly true for many industrial wastes. Coal-ash effluents may contain significant concentrations of up to 20 or more metals 13, 59). To evaluate the combined toxicity of metal mixtures, more information is required concerning possible antagonistic, additive, or synergistic interactions. 

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