Human Sample Collection Procedures

1 Biomarkers in Human Tissue Biopsy and Biofluid Samples 

For each priority biomarker, the amount of biofluid and/or tissue biopsy samples needed should be precalculated. The operations team should also decide whether extra biofluid sample volumes should be collected and banked for future retesting (as appropriate) and for bridging or cross-assay validation studies. If future exploratory studies are also in scope, the amount of tissue biopsy sample and number of biofluid aliquots per sample type should be predetermined for long-term biobanking. 

Evidence-based protocols for sample collection should be developed and implemented for each biomarker analyzed. When multiple biomarkers are to be analyzed, multiple types of collection containers/tubes may be necessary. 

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Mirex was detected (mean detection limit 3 pg/g [ppt])in 62% of 412 breast milk samples collected from women in all Canadian provinces (Mes et al. 1993). The mean, median, and maximum mirex concentrations detected in whole milk were 0.14, 0.08, and 6.56 ng/g (ppb), respectively, and for milk fat were 4.2, 2.3, and 124.5 ng/g, respectively. In previous studies, mirex residues were not detected. None of the 1,436 human milk samples collected in the United States in the late 1970s as part of the National Human Milk Study contained identifiable levels of mirex (Savage et al. 1981). A similar national study of nursing mothers in Canada (Mes et al. 1986) also failed to detect mirex in any human milk samples. The high rate of detection in the Mes et al. (1993) study was a result of improved analytical procedures and lower limits of detection. 

Experimental samples are mainly derived from tissue culture cells, laboratory animals, or human tissues collected from hospitals after surgical biopsies and autopsies. With human and animal tissue specimens, it is important to arrest metabolic processes within 5-10 min of collection in order to preserve mRNAs from degradation by internal enzymatic reactions (26,27). Most hospitals use 10% buffered formalin as a tissue fixative. Subsequently, each tissue slice is trapped in a paraffin block. Series of 4-5-pm-thick sections are cut and mounted on silanated slides. Formalin-fixed archival tissues have been successfully used in in situ PCR and in situ hybridization protocols (28-32). However, the procedure for RNA protection is not always followed. It is often difficult to alter or control the routine procedures of hospitals for the required protection of mRNAs in surgically removed human tissues. 

Human specimens. In our laboratory, we first developed a good laboratory practice (GLP)-validated procedure for quantification of intact rafAON in control human plasma. The rafAON assay validation endpoints were standard curve, between-run precision and accuracy, within-run precision and accuracy, effects of dilution and freeze thaw, stability of rafAON at -80° C, and 4°C in plasma for various times, specificity, integrity of rafAON during plasma sample collection and processing, and lipid interference. The reader is referred to a previous citation for further details (17,27). 

Noted earlier, contamination of plasma by either erythrocyte or external Pb would be very problematic with many plasma measurements, especially at lower exposures now encountered by human risk populations. Smith et al. (2002) included a measurement of hemoglobin content of plasma as one means of adjusting for this artifact in their PbP measurement protocol. External contamination is also very troublesome at the sample collection, laboratory manipulation, and measurement steps. Conventional field collection protocols and laboratory procedures are of limited use for PbP measurement. Precautions include use of extremely low Pb content reagents and sampling with special low-Pb blood tubes. NAS/NRC (1993) and Mushak (1998) have illustrated the huge impacts on accuracy of PbB measurement due to these artifacts. 

Errors in the use of POCTs may lead to inaccurate results that compromise patient safety and lead to harm. Using human-factors approaches such as simulation of the testing process (sample collection, test procedure and result output) and systan (training, data transfer, patient safety and intervention) can identity these risks and ntitigate them. 

Optimization of the sampling of chemicals and mixtures deposited on surfaces that could be sources of human exposures. Specific collection methods have been assessed and laboratory based research work is underway to define optimization procedures for sampling. 

Al fundamental question about the interpretation of acidic aerosol data is whether researchers can characterize past and current atmospheric concentrations and distributions (spatial and temporal) with sufficient accuracy for studies of their effects on ecosystems and human health. Part of the answer to this question can be provided by a review of the methods that have been used to measure the strong acid content of aerosol particles collected from the atmosphere. This chapter serves as such a review, and, in evaluating analytical procedures, it specifically assesses the ability of each procedure to overcome sampling artifacts, to distinguish between strong and weak acids, to properly partition strong acidity between gas-phase and aero-sol-phase species, and to quantitate strong acidity at the levels at which it is found in the ambient atmosphere. 

A number of procedures used to determine protein quality involve bioassays. Bioassays require feeding live animals protein ingredients for a specified period of time, and then estimating the nutritive value of the protein. Two such assays are the rat-based protein efficiency ratio (PER) bioassay and the human nitrogen balance assay (Dimes et al., 1994). Animal feeding experiments require chemical analyses of both the dietary inputs and then the metabolic output of the animal (e.g., body composition analysis, fecal sample analysis, collection, and assay for urine) from which the efficiency of protein metabolism can be predicted as well as how the protein supports animal growth and cell maintenance. 

This procedure allows the differentiation of odor active compounds from odorless substances within a complex mixture of volatiles. For decades this procedure has been successfully applied for aroma analyses of foods (Grosch, 1993). The mixture of volatile compounds either collected in a purified organic solvent extract or in a defined headspace volume is separated into its different components by means of GC and the effluent gas flow at the end of the GC capillary column is split between a FID and an experienced test person s nose. By sniffing the column effluent, the human nose is able to perceive the odor active compounds contained in a complex mixture and the test person can mark the corresponding spot in the FID chromatogram recorded in parallel and attribute a certain odor quality. A sample GC—O chromatogram of a solvent extracted material is shown in Figure 8.7. 

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