Substance biological action

Group of compounds Individual substances Biological action... 

Aerobic Treatment. The activated sludge process depends on aerobic biological action. In this case the microorganisms, in searching for food, break down the complex organic substances into simple stable substances. This process results in the removal of soluble and suspended organic matter from wastewater. 

As in many fields of research, new tools and techniques for measuring carotenoids in various systems are critical to support research progress. Several chapters discuss new methodologies to measure carotenoids (see Chapter 4), carotenoid metabolites/radicals (see Chapter 9), or carotenoids in vivo in complex biological systems, especially in the human eye (e.g., see Chapters 5 and 6). Other chapters describe the oxygenase enzymes that are essential components of carotenoid metabolism to active metabolites (see Chapter 19). The study of active metabolites includes the in-depth evaluation of carotenoid cleavage products (see Chapter 11) and carotenoid radicals (see Chapter 14) that may account for some of the biological actions observed for these unique substances. 

Where a substance causes concern as a result of some specific aspects of its biological action (e.g. a therapeutic class of which several members have produced positive oncogenic results), its pattern of toxicity or long-term retention (of drug or metabolites) detected in previous studies positive findings in genotoxicity studies. 

If the combination of a high-resolution separation system with a physicochemical detection principle is specific to properties of many harmful (toxic) chemicals, then a straightforward approach may be possible (27). Electron capture detection (ECD) registers electronegative compounds. Since the early 1960s, Lovelock (28) has pointed at the possible link between the ability of a substance to capture electrons and its biological action. 

Skoog, F. Miller, C.O. (1957). Chemical regulation of growth and organ formation in plant tissues cultured in vitro. Biological Action of Growth Substances, Symp. Soc. Exptl. Biol. 11, pp. 118-131. Cambridge University Press. 

Other studies have shown biological actions from these kinds of structure and indicate interrelationships between the chemicals in terms of their potencies. Tomita [229] found that the substances, vitamin A, vitamin K, vitamin E, /1-carotene, ubiquinone (15), phytol and squalene (16), from green-yellow vegetables could suppress the growth of tumour cells and enhance T-cell cytotoxicity, but /1-carotene, which does have both ends of the chain substituted with a bulky / -ionone ring on each end-group did not. Hydrophobic chain... 

Its biological action is not significantly stronger than that of endogenous substances. 

With the aid of this theory it is explained that just as in coloured substances the introduction of some auxochromic groups changes the colour of the substances, so in the war gases the presence of certain autotoxes can alter the type of biological action. Thus, for example, halogen introduced into the hydrocyanic acid molecule reduces the toxicity of the toxophor, —CN, and confers on the product lachrymatory properties. 

The physiopathological classification of the war gases, though used very widely, is even less exact than the others mentioned. In point of fact the biological action of these substances is extremely complex and in certain concentrations a gas may change its action to that of another group. 

Vitamin A is a generic term embracing substances having the biological actions of retinol and related substances (which are called retinoids). The principal functions of retinol are to ... 

Complex Formation. If a substance is not in solution, it cannot gain entrance to the cell and thus cannot affect the metabolism of an organism. Thus, complex formation (i,e, removal of a substance from effective solution) has a significant effect on the toxicity observed in any situation. It is most important in any toxicity situation to understand the potential of the substances present to partake in complex formation reactions. In some situations, complex formation can be predicted easily on the basis of the substances present. In other situations, complex formation is diflBcult to gage since it will result only after biological action alters some of the components. 

Clinical pharmacology and the biological action of the drug substance ... 

Substance P and Substance K are also known as tachykinins. They are a family of closely related peptides responsible for important biological actions including bronchoconstriction, salivation, vasodilatation. 

A major factor regulating the pharmacological or biological actions of substances delivered to the lumen of the airways is epithelial permeability. Passage of drug through the epithelium is prerequisite for an action or subepithelial target cells,... 

Dicoumarin is a white crystalline substance of slightly bitter taste. Its biological action is twofold. On the one hand, it is an antagonist of vitamin K, reducing the production of prothrombin in liver cells, which results in a decrease of blood coagulability. On the other hand, dicoumarin makes vein walls permeable, so that blood may penetrate the tissues of internal organs. As a result of this double action, animals bleed to death or die from cerebral haemorrhage. 

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