Complex Similar Action

In order to predict the effect of a mixture of chemicals with the same target receptor, but with different nonlinear dose-effect relationships, either physiological or mathematical modeling can be applied. For interactions between chemicals and a target receptor or enzyme, the Michaelis-Menten kinetics (first order kinetics but with saturation) are often applicable. This kind of action can then be considered a special case of similar combined action (dose addition). 

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Interactions Complex Similar Action and Complex Dissimilar Action... 

Chemicals in mixtures may interact with one another and modify the magnitude and sometimes also the nature of the toxic effect. As illustrated in Table 10.1, the combined action of chemicals that interacts can be divided into two categories complex similar action and complex dissimilar action (dependent action). 

It is highly likely that, for compounds thought to have complex similar actions, the observed deviations from the expected additivity in some cases are due to the fact that the compounds are acmally not acting at the very same site at the target receptor. This means that the compounds acmally have complex dissimilar actions and the combined action is misclassified as a complex similar action due to insufficient knowledge about the exact mechanisms of action. 

The hydride ion can act as a ligand and form hydride complexes similar in some ways to those of halides, although their stability is often limited by the reducing properties of the H ion. The most important complexes are the tetrahedral ions and normally found as the salts NaBH4 and LiAlH4. They may be made by the action of NaH or LiH on a halide or similar compound of B or Al,... 

Metal complexes Similarly to metal oxides, these compounds can be exploited for electrocatalytic (mediating) actions to facilitate electron transport between analyte and electrode surface [135-137]. Ferrocenes,... 

However, reversal of the order of addition produces mainly /7-(dimethylamino)-benzenesulfonic acid indictive of the sulfonating action of the complex. Similarly, sulfonation of AT-methylformanilide 339 with chlorosulfonic acid afforded the / -sulfonyl chloride 340 (Equation 108). ... 

The effect of histones on RNA synthesis in the chromosomes and on DNA-dependent synthesis in vivo has been the subject of several investigations in other laboratories also, among which the work of Allfrey and Mirsky (1962), Allfrey et al., (1963), and Frenster et al., (1963) may be mentioned in particular. These workers studied synfliesis of RNA and proteins by thymocyte nuclei, and in a series of earlier experiments, carried out in 1958-1961, they showed that histones definitely inhibit this synthesis. Polylysine has a similar action. However, exogeneous histones, when added to nuclei, possessed a complex inhibitory action, some of which was due to their toxic action on ATP synthesis and on amino acid activation. Accordingly, in a series of new e3q>eri-ments, they used the method of studying removal of native histones from nuclei with proteases and the effect of this removal on DNA-dependent synthesis of RNA and proteins. 

Mineralocorticoids foUow a mechanistic route similar to that of glucocorticoids, though differing in the proteins expressed. The activated MR-DNA complex promotes the expression of aldosterone-induced proteins (AIPs), which then act to increase conductance of the luminal membrane and concurrently increase pump activity of the basolateral membrane. These actions result from a number of AlP-influenced cellular characteristics,... 

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