Biological methods biomarkers

Griffin, P., Jones, K., and Cocker, J., Biological monitoring of polychlorinated biphenyls in plasma a comparison of enzyme-linked immunosorbent assay and gas chromatography detection methods, Biomarkers, 2, 193-195, 1997. 

Methods of measurement of pesticide exposures can be separated into two categories direct and indirect (Bristol et al., 1984 Nigg et al., 1990). Direct methods measure a pesticide residue in environmental media or on the skin surface before it has entered the body in order to estimate the potential dose. Indirect methods estimate the minimum absorbed dose by measuring residues in excreta, body fluids or tissues after exposure has occurred. Examples of direct methods are those that determine residues in air, water, food and on surfaces. Indirect methods may involve determination of the levels of specific pesticides, their metabolites or biological indicators ( biomarkers ), such as protein- or DNA-adducts, in blood, urine, feces, sputum, sebum, cerumen or adipose tissue. This chapter covers direct measurement methods only. 

Indirect method Estimates the minimum absorbed dose by measuring residues in excreta, body fluids or tissues after exposure has occurred. Indirect methods may involve determination of the levels of specific pesticides, their metabolites or biological indicators ( biomarkers ), such as protein- or DNA-adducts, in blood, urine, feces, sputum, sebum, cerumen or adipose tissue (Lewis, Ch. 3). 

The effects of the appropriate environmental matrices (soil, water, air, biological - for biomarker or exposure assessment studies) on assay performance must be well characterized and documented. The SOP must also include the degree of quality control necessary to ensure the satisfactory performance of the method. Quality control procedures must address the required sample preparation steps, reagent stability, instrumentation, data handling and analysis. In many immunoassay SOPs that the EPA has reviewed, quality control is totally lacking or minimally addressed particularly for the sample preparations. The Agency can provide direction on what is an appropriate degree of quality control based on the objective of the method. 

Methods for Determining Biomarkers of Exposure and Effect. GC/ECD, GC/MS, and GC/MC are analytical techniques used for measuring endosulfan in blood, urine, hand rinses, and various biological tissues and excreta at low- and sub-ppb levels (Coutselinis et al. 1976 Demeter and Heyndrickx 1978 Demeter et al. 1977 Griffith and Blanke 1974 Guardino et al. 1996 Kazen et al. 

A range of biomarkers (biological markers) have been developed for the detection of microorganisms using both their genetic (DNA and RNA) and biochemical components. Most methods have originated from studies on pure isolates and have been adapted to identify and quantify either the total or a sub.set of the microbial biomass in a sample. In these methods,. specific taxonomic or pheno-... 

Methods for Determining Biomarkers of Exposure and Effect. Analytical methods with satisfactory sensitivity and precision are available to determine the levels of americium in human tissues and body fluids. However, improved methods are needed to assess the biological effects of americium in tissues. 

Polyalphaolefin Hydraulic Fluids. No methods were identified for determining biomarkers of exposure or effect. Nonetheless, the available analytical methods for identifying C15 50 alkanes in biological tissues could be used to determine exposure levels (Ferrario et al. 1985a, 1985b Hesselberg and Seelye 1982). 

Analytical Methods for Determining Biomarkers of -Hexane in Biological Samples... 

MS has been successfully interfaced to both gas and liquid chromatography and the interface to CE has also been successfully developed. CE—MS is serving an analytical role in the area of small sample sizes commonly found in biological, biomarker, or cellular samples. Liquid chromatography is ideally suited for trace analysis when large amounts of sample are available. Compared to HPLC, CE offers different selectivity, higher efficiency, fast method development, and shorter analysis times. 

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