Detection and assay

The development of rehable uv analysis permitted the dependable detection and assay of the provitamins and vitamins. Prior to this, the Lieberman-Bouchard chemical test was used, but the color reaction gave many false positives and was relatively inaccurate. 

Toxicological problems among infants are relatively common. For example, it is now routine to follow the course of changes in Dilantin levels of patients who are being treated for various convulsive disorders (12). It is also important to be able to detect and assay for other drugs that are used in the newborn, such as various other anticonvulsants, salicylates, and a host of others. 

Fournier E. Sonnier, M, Dally S (1978) Detection and assay of organophosphate pesticides in human blood by gas chromatography. Clin Toxicol 12 457-462. 

Immunoassay Detection and assay of substances by serological (immunological) methods in most applications the substance in question serves as antigen, both in antibody production and in measurement of antibody by the test substance. 

The existence of photoreversible, but not of heat-reversible, absorbance change in irradiated poly dI dC was taken to prove that the photoproducts are entirely dimers (in contrast to those in poly C irradiations where the product is almost entirely the hydrate82a). It was possible to detect dimers of uracil as well as those of cytosine, by means of the much slower photoreversal of uracil dimers. In the acid hydrolysates of irradiated dl-dC, both uracil dimers and uracil could be identified. Enzymatic hydrolysis (snake venom phosphodiesterase) does not split pyrimidine dimers, and the products of such hydrolysis of irradiated tritium-labeled poly dl dC contained trinucleotides shown by radioactivity to contain cytosine dimers. Thymine dimers were formed in the photolysis of the poly dA dT, and were detected and assayed by the same methods. The yield of thymine dimers in irradiated poly... 

P Resmini. A rapid electrophoretic method for the detection and assay of soft wheat in hard wheat flour (semolina) and pasta (macaroni). Tecnica Molitoria 19 145-150, 1968. 

Even though our understanding of the possible types of lipid-protein interactions in membranes has developed only recently, it was evident to early investigators that neutral solvents per se were the most effective for isolation purposes. Perhaps the most widely used solvent extraction procedure for many years was that employing a mixture of ethanol-diethyl ether (usually 1 3, v/v). This technique involved extraction of a tissue with this solvent combination for several hours at 55-60°C (Bloor, 1928). However, as more refined techniques were developed for the detection and assay of lipids, it became evident that this solvent (and condition) could have a deleterious... 

The water-soluble fraction (from the original extraction of the reaction mixture described above) is evaporated to dryness, dissolved in 2 ml water, and applied to a Dowex AG 50 W x 8 column (H form, 200-400 mesh-column size, 0.6 x 5 cm). Water is used as the eluant, and the P-containing components are collected. The latter could be evaporated to dryness and silylated using the reagent pyridine/Tri-Sil TBT and BSTFA (1 2 2, v/v) (Pierce Chemical Co., Rockford, 1L). Subsequently an aliquot of this TMS derivative can be analyzed directly by the gas-liquid chromatography technique of Karlsson (1970). For further information on the detection and assay of choline and phosphocholine, suggested reading is an article by Kennedy (1991). 

Two more recent routes to the detection and assay of ethanolamine and related compounds deserve mention here. Sundler and Akesson (1975) reported an elegant method for the analysis of ethanolamine and possible derivatives (e.g., O-phosphoethanolamine) using the dansyl(5-dimethylaminonaphtha-lene-l-sulfonyl) derivatives and their fluorescence characteristics, in the 0.05-5 xM range. McMasters and Choy (1992) outlined a procedure for the determination of ethanolamine, by reverse-phase HPLC, as the phenythio-carbamyl derivative. A quantitative evaluation could be obtained in the 0.1-10 nmol range. 

Detecting and assaying lectins are made possible by the ability of lectins to agglutinate red blood cells. The specificity of lectins is in terms of the simple sugars that inhibit the agglutination assay. Some lectins, of course, recognize somewhat more complex carbohydrate structures. Table 2 gives alist of some lectins to illustrate the features of this class of proteins. 

The formation of colored products by the action of a variety of oxidating agents has been used for the detection and assay of pheno-thiazine derivatives. The use of chlorpromazine as an indicator... 

In addition to the studies cited above, there are several others showing that phenyl phosphate is much more readily hydrolyzed than j3-glycerophosphate by acid phosphatase from human erythrocytes, whereas no such marked difference exists with respect to human prostatic phosphatase (B2, Tl, T3). Unfortunately, there do not appear to be any systematic investigations of the substrate-velocity relationship for the acid phosphatases of other human tissues. In general, the available data would indicate that /3-glycerophosphate is a more specific substrate than phenyl phosphate for the detection and assay of acid phosphatase coming from the prostate. 

White, C.A. and Kennedy, J.F. 1981. Manual and automated spectrophotometric techniques for the detection and assay of carbohydrates and related molecules, Tech. Carbohydr. Metab., B312 1-64. 

F. Beisson, A. Tiss, C. Riviere, and R. Verger, Methods for lipase detection and assay a critical review, Eur. J. Lipid Sci. Technol., 2000, pp. 133-153. 

Chun, J. (1998) Detection of cells undergoing programmed cell death using in situ end-labeling plus, in Apoptosis Detection and Assay Methods (Zhu, L. and Chun, J. M., eds.), Biotechniques Books, Natick, MA, pp. 7-14. 

W7. Wilson, H., and Fairbanks, R. A., Micro method for the detection and assay of steroid Cji, 17-hydroxy-a-glycols. Arch. Biochem. Biophys. 64, 457—466 (1955). 

To elucidate the urinary steroid excretion pattern in various cases of the adrenogenital syndrome Bongiovanni (B28) used a long but excellent technique involving digitonin, and Girard separations, multiple chromatography on silica-gel and paper, and a variety of colorimetric techniques for detection and assay. 

These needs provide scope for considerable innovation and one procedure that is receiving considerable attention has its basis in immunochemistry. Thus, specific and sensitive immunochemical methods are being developed for the detection and assay of specific protein and DNA adducts formed by reaction with ultimate genotoxic agents. Immunological methods have... 

A CZE procedure for detection and assay of protein kinase and phosphatase activities in complex biological mixtures has been developed by Dawson et al. Thephosphorylated and dephosphorylated forms of several peptides were resolved using an uncoated capillary and a 150 mM phosphoric acid buffer at pH 2.0 or pH 5.0. Furthermore, the CZE-based assay was capable of resolving a peptide phosphorylated on different sites and permitted the quantification of each peptide. Since this application, much research has been done on protein kinase assays based on CE. 

One draw-back of bioassay however is its inherent non-specificity. Reactions to bioactive substances not related to this field of biochemistry can generally be blocked by pretreatment of the assay organ with specific antagonists and inhibitors [212]. However, even using these precautions, many bioassay systems for detection and assay of TXAj are not entirely specific for this compound but react in a similar fashion also to the endoperoxides. This is the case with two of the most frequently used systems platelets and the rabbit aorta. Since endoperoxides may be present in parallel with TXA 2 in many biological situations, this non-specificity may create a problem. One possible solution is to use an assay more specific for TXAj the rabbit mesenteric artery, for example, has been reported to be contracted only by TXA 2 [215]. 

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