Reactions, chemical immunological

A number of chemical compounds are potent sensitizers that can lead to serious immunological reactions. Immunotoxicology explores interactions between chemical compounds and the immune system. Chemicals can amplify, attenuate, or otherwise modify immunological reactions subsequent to exposure. - ... 

An argument against an immunologic reaction in non-immediate hypersensitivity reactions has been the lack of a hapten. Non-ionic RCM are chemically non-reactive... 

A most important technique which has been developed as an extension of the isotope dilution principle is that of radioimmunoassay (RIA). Analyses by this method employ substoichiometric amounts of specific binding immuno-chemical reagents for the determination of a wide range of materials (immunogens) which can be made to produce immunological responses in animals such as sheep or rabbits. It is possible to combine the specificity of an immunochemical reaction with the extreme sensitivity of radiotracer detection. Analytical methods based upon these principles have achieved wide applicability in the determination of organic compounds at trace levels. 

A sophisticated respiratory host defence system has evolved to clear airborne particles and potential pathogens in inspired air [106, 143], The system comprises mechanical (i.e. air filtration, cough, sneezing and mucociliary clearance), chemical (antioxidants, antiproteases and surfactant lipids) and immunological defence mechanisms and is tightly regulated to minimise inflammatory reactions [92, 143],... 

In addition to diseases of important organs such as the lungs, the liver, and the kidneys, hereditary or acquired characteristics such as immunodeficiency and hypersensitivity may also influence sensitivity to xenobiotics. For example, atopies (individuals with immunologically mediated allergy) may develop life-threatening reactions to a chemical at an exposure level that is insignificant for the population in general (KEMI 2003). 

The interaction of a chemical (hapten) with epidermal proteins (carrier) can result in a hapten-carrier complex capable of activating skin-associated lymphoid tissue (sensitisation) and dissemination of antigen-specific T l)unphocytes (induction). Subsequent encoimter with the same or cross-reactive chemicals can result in the elicitation of a characteristic inflammatory skin reaction. The clinical condition is referred to as allergic contact dermatitis and is characterised by erythema, oedema, vesiculation and pruritus. Allergic contact sensitisation is, therefore, classed as a cell-mediated immunological response to chemicals that contact and penetrate the skin. 

Isocyanates mediate their toxicity through a high degree of chemical reactivity. These reactions can result in cross-linkages of biological macromolecules that lead to the denaturation of proteins, the loss of enzyme function, and the formation of immunologic reactivities. 

Bio)chemical sensors can be active or passive according to whether they use a sensing microzone to accommodate a chemical or biochemical reaction and/or a biochemical e.g. immunological) or physico-chemical separation e.g. sorption). It should be noted that passive sensors e.g. a fibre-optic tip immersed in an industrial process stream) do not meet one of the essential requirements included in the definition of sensors as regeirds composition... 

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