Data Interpretation and Sources of Error

In this study, the enzyme-linked immunosorbent assays (ELISA) were modified to detect 3-PBA in plasma (including the adducted form) and urine among a large group of consumers and farmers in an agricultural area. The samples were collected on the same day in the morning from 100 consumers (50 females, 50 males) and 100 farmers (50 females, 50 males) in the Fang district, Chiang Mai province, northern Thailand. The ELISA was very sensitive having an IC50 value of 26.7 and 15.3 ng/mL, a limit of quantitation of 5 and 2.5 ng/mL and a limit of detection of 1.08 and 1.94 ng/mL for plasma and urine, respectively. These methods had low (< 5%) intra- and inter-assay coefficients of variation. The extraction technique satisfactorily eliminated the matrix effect from samples before ELISA analysis, yielding good recoveries (85.9–99.4% and 87.3–98.0%, respectively). For the volunteer study, the detection rate for plasma 3-PBA was 24% in consumers and 42% in farmers, but the median and range values were similar (median 5.87 ng/mL, range 5.16–8.44 ng/mL in consumers and 6.27 ng/mL, range 4.29–9.57 ng/mL in farmers). The rate of detection in the urine was similar (76% and 69%, in consumers and in farmers), yet the median concentration was significantly higher in farmers (8.86 μg/g creatinine in consumers vs 16.1 μg/g creatinine in farmers) and the range also much wider in farmers (1.62–80.5 μg/g creatinine in consumers and 0.80–256.2 μg/g creatinine in farmers). There was no correlation between plasma 3-PBA and urinary 3-PBA concentrations in the study presumably because plasma 3-PBA is a measure of cumulative exposures while urinary 3-PBA reflects acute exposures. In addition, metabolism and excretion of pyrethroids varies by individual. Nevertheless, this study demonstrated that these volunteers were exposed to pyrethroids. To our knowledge, this is the first report that compared plasma 3-PBA and urinary 3-PBA in a large group of volunteers. The ELISA method provided higher sample throughput with lower cost as compared to the instrumental analysis.

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“…Minor differences between operations, preparation of calibrators, or reagent degradation are among some of the causes of such variations. [31] …”

Section: Resultsmentioning

confidence: 99%

Determination of the pyrethroid insecticide metabolite 3-PBA in plasma and urine samples from farmer and consumer groups in northern Thailand

Thiphom

Prapamontol

Chantara

et al. 2013

Journal of Environmental Science and Health, Part B

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“…The possible underestimation of NEP levels caused by protein degradation due to the presence of proteases is considered important and therefore protease inhibitors (typically a protease inhibitor cocktail) should be included in the extraction buffer (e.g. Herman and Shan, 2011;Laing and Christeller, 2004). If protease inhibitors are not used, the justification should be provided.…”

Section: Extraction Buffermentioning

confidence: 99%

“…The analytical method may be significantly influenced by components in the tissue extract resulting in a non-specific response commonly referred to as a 'matrix effect' which is one of the parameters that could affect the method accuracy (EMA, 2011;FDA, 2018;Jenkins et al, 2015;Herman and Shan, 2011). In order to assess whether there are any matrix effects, it should be demonstrated that the analytical method is not significantly affected by the presence of matrix components.…”

Section: Matrix Effectsmentioning

confidence: 99%

Explanatory note on the determination of newly expressed protein levels in the context of genetically modified plant applications for EU market authorisation

Paraskevopoulos¹,

Ramon²,

Dalmay³

et al. 2018

EFS3

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Genetically modified organisms are subject to a risk assessment and regulatory approval before entering the European market. According to legislation (Directive 2001/18/EC, Regulation (EC) No 1829/2003 No 503/2013) and the EFSA guidance documents on the risk assessment of food and feed from genetically modified (GM) plants and on the environmental risk assessment of GM plants, applicants need to perform a molecular characterisation of any DNA sequence inserted in the GM plant genome. When a GM plant is designed to produce one or more newly expressed proteins, an aspect of the risk assessment process is to characterise these proteins and to reliably determine their levels in the GM plant tissues. A number of methods to measure protein expression levels are used and several experimental factors within these methods are of critical importance in order to obtain reliable results. This explanatory note provides details on key methodological aspects for the determination of newly expressed protein levels that should be considered and reported by applicants in order to harmonise the information in GM plant applications submitted to EFSA.

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Validation Parameters for Quantitating Specific Proteins Using ELISA or LC-MS/MS: Survey Results

Settlage

Eble

Bhanushali³

et al. 2016

Food Anal. Methods

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Data Interpretation and Sources of Error

Cited by 3 publications

References 42 publications

Determination of the pyrethroid insecticide metabolite 3-PBA in plasma and urine samples from farmer and consumer groups in northern Thailand

Determination of the pyrethroid insecticide metabolite 3-PBA in plasma and urine samples from farmer and consumer groups in northern Thailand

Explanatory note on the determination of newly expressed protein levels in the context of genetically modified plant applications for EU market authorisation

Validation Parameters for Quantitating Specific Proteins Using ELISA or LC-MS/MS: Survey Results

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