Enzyme linked immunosorbent assays biomarker development

Additionally it has been our experience that mass spectrometry as a routine detection/identification technique for bacteria is not well received by microbiologists and clinicians who prefer less expensive, less complicated approaches to bacterial typing and identification, such as methods based on polymerase chain reaction (PCR) and enzyme-linked immunosorbent assays (ELISA). For that reason we have adapted our MS approach to serve as a means of biomarker discovery that feeds candidate proteins or leads into development as PCR targets or other immunoassay techniques. 

Methods for Determining Biomarkers of Exposure and Effect. No biomarker has been identified that can be quantitatively related to dinitrophenol exposure (see Section 2.5.1) however, the presence and the amount of 2,4-DNP and 2-amino-4-nitrophenol, a metabolite in the urine, can be used as rough indicators of the intensity of exposure (see Section 2.5.1). The methods presently available for determining 2,4-DNP and 2-amino-4-nitrophenol (diazotization) in urine are outdated (Gisclard and Woodward 1946). An enzyme-linked immunosorbent assay (ELISA) is available for the quantitation of 2-amino-4-nitrophenol in water samples, but is not effective in urine (Li et al. 1991). It would be useful to develop an updated routine method for determining 2,4-DNP, 2-amino-4-nitrophenol, and 4-amino-2-nitrophenol in urine with well-defined detection limits, precision, and accuracy. 

PSA is one of the most widely used cancer biomarkers. It is a chymotryp-sin-like serine protease that is produced by epithelial cells of the prostate gland and secreted into the prostatic fluid. Prostate-cancer invasion disrupts the epithelial membrane barrier leading to elevated serum levels of PSA. Detection of PSA in blood can therefore be useful in the diagnosis of prostate abnormalities and for evaluation of prostate cancer therapy efficacy [21]. Two different forms of PSA are immunologically detectable the free form (MW 34 kDa) and a complex with a-l-antichymotrypsin (MW 96 kDa). Diagnostic assays developed for detection of PSA (e.g., enzyme-linked immunosorbent assays) detect total PSA concentrations down to 0.1 ngmL [22,23]. 

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