Biomarkers, general discussion

In the present chapter, we first provide some general information concerning the chemistry of waxes and lipids currently encountered in various items from our cultural heritage and we detail the main protocols based on direct mass spectrometry that have been developed so far. We then discuss the mass spectra obtained by EI-MS on a range of reference substances and materials sampled from museum and archaeological artefacts. We then focus on the recent possibilities supplied by electrospray ionisation for the elucidation of the structure of biomarkers of beeswax and animal fats. 

The formation of life and how to recognise it is the central problem in astrobiology. All searches for other life forms will be prejudiced horribly by the study of the only example we know to date - life on Earth. Despite attempts to classify the general roles of molecules in definitions of life as biomarkers, there have been many discussions of possible biomarkers, including ... 

Methods for Determining Biomarkers of Exposure and Effect. As discussed above, the presence of radium in biological materials is usually determined by virtue of its radioactivity. Methods available for the determination of radioactivity in biological materials include alpha spectroscopy and gamma spectrometry, which is more convenient, but generally less sensitive, than alpha spectroscopy (Joshi 1987). It would be useful to have additional data on the sensitivity and accuracy of the methods that are currently in use. 

Participants in public-health studies that measure hundreds of biomarkers might give informed consent only with respect to the general objectives of the study on the grounds that detailed discussion of each biomarker is not feasible. However, failing to provide more detailed information raises ethical questions. The committee recommends research... 

It is usual whenever biologic samples are obtained in medical practice or in any health encounter for results to be expressed in relation to normal. In fact, a relationship to normal is the question almost every subject asks first when presented with such information. For biomonitoring results, it is a generally meaningless question— normal for human-made chemicals or chemicals that did not enter the environment except for human activity, is actually zero. Despite that, many laboratories report results, such as blood lead concentrations, in just this way—a practice likely to result in confusion. For example, it is not rare to see reports of blood concentrations that contain the phrase normal for industrial workers. In truth, such concentrations may be common in industrial workers, or even typical, but hardly normal in the usual meaning of that word in relation to health. Such comparisons are especially problematic for biomarkers whose relationship to health and environmental sources is less well studied. The discussion below touches briefly on the scientific issues raised by such implicit or explicit comparisons of results with reference ranges. 

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