Dynamic toxicity factor

As for the rate of heat release (cf. Section 3.1.3) and rate of smoke generation (cf. Section 4.1.1.2), a rate of toxicity production was introduced in terms of the unit surface of the sample. It led to the definition of the dynamic toxicity factor ... 

Experimental dynamic toxicity factors of some materials... 

Tsuchiya, Y. Dynamic toxicity factor — evaluating fire gas toxicity. /. Combustion Toxi-cology, 8, No. 8 187 (1981)... 

Abrasion. When evaluating the possibility of installing a seal in a liquid that has entrained solids, several factors must be considered. Is the seal constructed in such a way that the dynamic motion of the seal will be restricted by fouling of the seal parts The seal arrangement that is usually preferred when abrasives are present is a flushed single inside type with a face combination of very hard material. Flowever, factors such as toxicity or corrosiveness of the material may dictate that other arrangements be used. 

Use of in vivo Tests. In vivo tests are more relevant indicators than are in vitro tests of immunotoxicity since the dynamic interactions between the various immuno-components, as well as the pertinent pharmacokinetic (absorption, distribution, plasma concentrations) and metabolic factors, are taken into consideration. However, it is important to select the appropriate animal model and to design the protocol such that it will accurately reflect drug (or relevant metabolite) exposure to humans. For example, one should consider species variability when selecting the animal model, since biological diversity may further obscure the ability to accurately predict human toxicity. 

It is necessary to appreciate both for a mechanistic view of toxicology. The first of these includes the absorption, distribution, metabolism, and excretion of xenobiotics, which are all factors of importance in the toxic process and which have a biochemical basis in many instances. The mode of action of toxic compounds in the interaction with cellular components, and at the molecular level with structural proteins and other macromolecules, enzymes, and receptors, and the types of toxic response produced are included in the second category of interaction. However, a biological system is a dynamic one, and therefore a series of events may follow the initial response. For instance, a toxic compound may cause liver or kidney damage and thereby limit its own metabolism or excretion. 

Although trace elements typically occur at concentrations of less than 1 ppb (part per billion) (or pg L-1, also reported in molar units), these elements are important in estuaries because of their toxic effects, as well as their importance as micronutrients for many organisms. The fate and transport of trace elements in estuaries are controlled by a variety of factors ranging from redox, ionic strength, abundance of adsorbing surfaces, and pH, just to name a few (Wen et al., 1999). The highly dynamic nature of... 

The CSAFs for toxicodynamic components are most simply, ratios of the doses which induce the critical toxic effect or a measurable related response in vitro in relevant tissues of animals and a representative sample of the healthy human population (interspecies differences) or in average versus sensitive humans (interindividual variability). At its simplest, then, replacement of the dynamic component of the default factor for interspecies differences is the ratio of the effective concentrations in critical tissues of animals versus humans (e.g., ECio animai/ECio human) for interspecies differences and in healthy human and susceptible subpopulations for interindividual variability (e.g., the ECio averag[Pg.531]

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