Radioimmunoassay, applications

C. C. Harris, R. H. Yolken, H. Krokan, and I. C. Hsu, Ultrasensitive enzymatic radioimmunoassay Application to detection of cholera toxin and rotavirus, Proc. Natl. Acad. Set., USA, 76 5336-5339 (1979). 

The immunochemical interaction between the antigen and antibody is very specific. By labeling either the antigen or antibody, the method s sensitivity is increased. The most frequently used labels to increase sensitivity are radionucHdes (see Radioisotopes) where the assay process is called radioimmunoassay (RIA), or en2ymes where the assay is named en2yme immunoassay (ElA) (see Enzyme applications). 

Utility. Insufficient data Is available on the measurement of 1,25(0H)2D3 for evaluation of Its utility In clinical medicine. A major breakthrough In methodology will be needed before routine application will be possible. This could come with the development of a battery of radioimmunoassays for the measurement of all of the vitamin D metabolites. So far, however, the development of antibodies to vitamin D and Its metabolites has been limited by apparently Irreversable changes In the Important B ring of the sterol which occur during Its conjugation to Immunogenic proteins. 

The first application of immunologically based technology to pesticides was not reported until 1970, when Centeno and Johnson developed antibodies that selectively bound malathion. A few years later, radioimmunoassays were developed for aldrin and dieldrin and for parathion. In 1972, Engvall and Perlman introduced the use of enzymes as labels for immunoassay and launched the term enzyme-linked... 

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. 

Table 10.1 A selection of compounds for which radioimmunoassays have been developed, indicating the wide applicability of the technique...

The scope of applicability of radioimmunoassay is rapidly expanding with the dawn of each day as RIA is being developed for newer pharmaceutical substances. It has attained wide recognition and application both in vitro and in vivo measurements of compounds of interest like insulin, gastrin, glucagon, and growth hormones on one hand whereas drugs like ... 

The radioimmunoassay technique has been gainfully exploited in a variety of novel applications of which only the two important aspects stated below will be discussed briefly, namely ... 

Part—VI has been solely devoted to Miscellaneous Assay Methods wherein radioimmunoassay (RIA) (Chapter 32) has been discussed extensively. Various arms of theoretical aspects viz., hapten determinants and purity importance of antigenic determinants and analysis of competitive antibody binding of isotopically labeled compounds. The applications of RIA in pharmaceutical analysis, such as morphine, hydromorphone and hydrocordone in human plasma clonazepam, flurazepam in human plasma chlordiazepoxide in plasma barbiturates, flunisolide in human plasma have been described elaborately. Lastly, the novel applications of RIA-techniques, combined RIA-technique-isotope dilution and stereospecificity have also been included to highlight the importance of RIA in the analytical armamentarium. 

Radioactive isotopes provide a very convenient way of monitoring the fate or metabolism of compounds that contain the isotopes. When used in this way, the isotope is described as a tracer and compounds into which the radioactive atom has been introduced are said to be labelled or tagged. The labelled molecules need only comprise a very small proportion of the total amount of the unlabelled radioactive substance because they act in the same way as the non-radioactive substance but can be detected very much more easily. The varied applications of tracers in biochemistry range from studies of metabolism in whole animals or isolated organs to sensitive quantitative analytical techniques, such as radioimmunoassay. Phosphorus-32 is used in work with nucleic acids, particularly in DNA sequencing and hybridization techniques. In these instances the isotope is used as a means of visualizing DNA separations by autoradiographic techniques. 

Luft, R. Yallow, R. S. "Radioimmunoassay Methodology and Applications in Physiology and in Clinical Studies" George Thieme Verlag Stuttgard, 1974. 

This report describes the development of a radioimmunoassay (RIA) for one of the major PSP (saxitoxin, la) which is based on our successful production of antibodies to a stable saxitoxin derivative-bovine serum albumin conjugate. The application of the RIA to the analysis of PSP contaminated clam extracts and the problems which must be addressed in the development of a routine immunoassay for the PSP are discussed. 

This chapter reviews the year s published work on physical and analytical aspects of steroid chemistry. No attempt has been made to survey the enormous number of routine applications of spectroscopic methods to structure determination. Attention has been concentrated mainly upon those developments of a fundamental nature which increase our understanding of the physical techniques and the phenomena which they explore. The major advances reported this year in the area of spectroscopy lie in the interpretation and applications of Cn.m.r. tritium n.m.r. has made its appearance as a method for the analysis of labelled steroids. The short sections on analytical methods give the Reviewer s selection of significant advances in radioimmunoassay and chromatographic methods of interest to chemists. 

Apart from radioimmunoassays, various enzyme-linked immunosorbent assays have been described as well. Campbell et al. (42) first reported a sensitive and specific ELISA using polystyrene tubes and a polyclonal antibody. However, the performance of this method was not evaluated with real samples but only with standards and aqueous muscle tissue extracts. Sensitive ELISAs were also developed for the determination of chloramphenicol in milk (43) and eggs (44) the results drawn by the latter assay correlated well with those obtained by application of a radioimmunoassay. 

Today the largest number of applications of radiotracers is in biology and medicine. Because of the large number of applications, it is beyond the scope of this work to review them in any detail. Instead, we shall focus on three specific applications, one that is very old, one that is middle-aged, and one that is adolescent in its scope, if not in its development. We refer to autoradiography, radioimmunoassay, and DNA (deoxyribonucleic acid) analysis, respectively. 

M. Sisak, M. Franek and K. Hruska, Application of radioimmunoassay in the screening of polychlorinated biphenyls, Anal. Chim. Acta, 311 (1995) 415-422. 

The role of the immunoassay, especially the radioimmunoassay (RIA), in clinical biochemistry has been the major factor in the tremendous advances made in that field since its introduction in 1959 (11). At present the RIA is the most powerful analytical tool available for quantitative detection of molecules of diverse structure and function in biological fluids of human, animal and now plant origin. The immunoassay comprises a unique combination of sensitivity and specificity as well as precision and applicability. With this assay technique, it is now possible to detect and very accurately measure compounds at endogenous physiological concentrations which frequently are in the range of 10 M or lower. In Table II the major characteristics of the immunoassay are listed. This method is versatile, specific, can be utilized for almost an unlimited number of compounds and has a high throughput potential. 

Application of 125I Radioimmunoassay to Measure Inhibition of Precipitin Reactions using Carbohydrate-Specific Antibodies, P. H. Boullanger, A. Nagpurkar, A. A. Noujaim, and R. U. Lemieux, Can. J. Biochem., 56 (1978) 1102-1108. 

For mycotoxin analyses radioimmunoassay (RIA), enzyme-linked immunosorbent assay (ELISAs) and affinity chromatography are the principal immunochemical methods in commercial application. Immunoaffinity columns or cartridges for specific mycotoxins are now being increasingly used in preliminary clean-up of extracts prior to final analysis by HPLC or GLC methods. 

Corrie, J.E.T., W.A. Ratcliffe, and J.S. Macpherson. 1981. Generally applicable 125 iodine-based radioimmunoassays for plasma progesterone. Steroids 38 709-717. 

Aaltonen L, Kanto J, Iisalo E, Pihlajamaki K (1984) Comparison of radioreceptor assay and radioimmunoassay for atropine pharmacokinetic application. Eur J Clin Pharmacol 26 613-617... 

Current research involves the use of radioimmunoassay to quantitate testosterone and estrogen in dried blood samples (22, 24). The ultimate goal of this research will be to determine the sexual origin of the stains. In the past, researchers have attempted this by identifying Barr bodies and Y chromosomes using differential fluorescence staining with quinacine however, these tests required a substantial amount of blood deposited as a thin film on a non-porous surface and are therefore limited in their application (19, 20, 21). The sensitivity and basic technique of radioimmunoassay will permit the analysis of bloodstains on virtually any surface and should also be applicable to very small ones. 

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