Immunoassays theophyllin

Catalase has also been used as an enzyme label in competitive heterogeneous enzyme immunoassays. Catalase generates oxygen from hydrogen peroxide with the oxygen determined amperometrically with an oxygen electrode. This approach has been demonstrated for a-fetoprotein theophylline and human serum albumin... 

The determination of theophylline in plasma can also be accomplished by various immunoassay techniques.66-67 Theophylline was also determined by a polarization fluoroimmunoassays but found to have a caffeine interference.88. In a more research oriented application, the interaction of caffeine with L-tryptophan was studied using h NMR with the results indicating that caffeine interacted with tryptophan in a 1 1 molar ratio through parallel stacking.69... 

Koup, J.R. and Brodsky, B., Comparison of homogeneous enzyme immunoassay and high pressure liquid chromatography for the determination of theophylline concentration in serum, Am. Rev. Respir. Dis., 117,1135,1978. 

Oellerich, M., Klupmann, W.R., Beneking, M., Sybrecht, G.W., Staib, A.H., and Schuster, R., Determination of theophylline in serum by nonisotopic immunoassays (EMIT, SLFIA, NIIA) and HPLC-CA comparative study, Fresenius Z. Anal. Chem., 311,355,1982. 

Tibi, L. and Burnett, D., Interference by caffeine in polarization immunoassays for theophylline, Ann. Clin. Biochem., 291 1994. 

Figure 6.1. Fluorescence polarization immunoassay for theophylline. (A) Effect of theophylline rabbit antiserum ( ) and normal rabbit serum (A) on the fluorescence polarization of the theophylline-umbelliferone conjugate. (B) Fluorescence polarization of the theophylline-umbelliferone conjugate in the presence of varying concentrations of theophylline. (Reprinted from Ref. 1, with permission from Academic Press.)...

Figure 6.2. Chemical structure of 8-[3-(7-/)-galactosylcoumarin-3-carboxyamido )propyl ] theophylline (B) used in the homogeneous substrate-labeled fluorescent immunoassay for theophylline (A). (Reprinted from Ref. 3, with permission from the American Association for Clinical Chemistry.)...

L Steinmann, J Caslavska, W Thormann. Feasibility study of a drug immunoassay based on micellar electrokinetic capillary chromatography with laser-induced fluorescence detection—determination of theophyllin in serum. Electrophoresis 16 1912-1916, 1995. 

Figure 15.6 Comparison of the values measured by an enzyme-multiplied immunoassay technique (EMIT) assay and a molecularly imprinted sorbent assay (MIA) for determination of theophylline in 32 patient serum samples. The correlation coefficient was 0.98. Reprinted from Vlatakis et al. (1993). Copyright 1993 Macmillan Ltd.

Niemann, A., Oellerich, M., Schumann, G., Sybrecht, G.W. (1985). Determination of theophylline in saliva, using fluorescence polarization immunoassay (FPIA). J. Clin. Chem. Clin. Biochem., 23(11), 725-732. 

The MIP-ILAs based on a direct format will be described elsewhere. ILAs based on indirect methods will be reviewed in this chapter. Like immunoassays, the first MIP-ILA, reported in 1993 by the Mosbach group [25] for the analysis of theophylline and diazepan, was based on a radioactive tracer. Since this work, many other indirect MIP-ILAs have been developed using non-isotopic tracers such as fluorophores, enzymes, or electroactive probes. 

Very recently, von Heeren et al. [59] have performed MECC separations with SCCE. In particular, these authors demonstrated the application of microchip MECC to biologically relevant samples such as labeled urine. A competitive immunoassay for monitoring patient serum levels of theophylline was carried... 

A robust assay for theophylline was established within the clinical range of 10-20 pg/mL [330]. Since the Ab-Ag complex can be mobilized, no additional internal standard was needed [330], as in an immunoassay study for cortisol [1006],... 

What are the two buffer additives used in the on-chip theophylline immunoassay Explain the functions of these two additives. [330] (4 marks)... 

In the on-chip theophylline homogeneous immunoassay, the antibody-antigen complex can be separated from the antigen. Why can such a separation be successful, but not in the case of the cortisol assay [330,1006] (2 marks)... 

Chiem, N., Harrison, D.J., Microchip-based capillary electrophoresis for immunoassays analysis of monoclonal antibodies and theophylline. Anal. Chem. 1997, 69, 373-378. 

An MECC immunoassay for serum theophylline was achieved on the cyclic CE microstructure, one to two orders of magnitude faster ( 30 sec) than the comparable separation using conventional fused silica capillaries, with higher efficiency and at no expense to accuracy or precision. The glass channels were not coated for these experiments, but they were rinsed with... 

Haga et al. developed another type of immunosensor by combining an enzyme membrane immunoassay and an enzyme sensor using oxygen electrodes (HI). In this assay antigen molecules (theophylline) are attached on the surface of the liposomes and an enzyme (horseradish peroxidase) is encapsulated in the sensitized liposome. When antibody (antitheophylline antibody) and complement are added, the enzyme is released by the liposome lysis. The enzyme activity with the NADH-NAD reaction can be determined by the oxygen electrode. When antigen is added, it competitively binds to antibodies, then liposome lysis and enzyme activity are decreased. The sensitivity of this method for theophylline determination was reported as 0.7 ng/ml. 

Chiem NH, Harrison DJ. Microchip systems for immunoassay an integrated im-munoreactor with electrophoretic separation for serum theophylline determination. Clin Chem 1998 44 591-598. 

Commercial immunoassay kits are available for the determination of theophylline in serum or plasma. 

The quantitative determination of drugs by radio-immunoassay techniques using imprinted polymers instead of natural antibodies was investigated by Mosbach. Theophyllin, Diazepam and Morphine were recognised and cross-reaction tests with other but sterical similar molecules, gave similar results like the established antibody reactions [449]. Eventually the expensive antibodies can be replaced by cheap synthetic imprinted polymers [474]. 

Wu, T. G. and Durst, R. A. (1990). Liposome-based flow injection enzyme immunoassay for theophylline. Microchimica Acta 100 187-195. 

---