All Time Favs
MA Citizens for
Real Texas Freedom
16. ON THE PROBLEMS OF TOXICOLOGY
M. Lotti and P. Nicotera (University of Padua, IT) discuss toxicology, the
authors making the following points:
- Several key advances in biology and medicine in the past were brought
about by studies of poisons. The eludication of the mechanism of carbon
monoxide toxicity by Claude Bernard (1813-1878), which led to the
understanding of the function of hemoglobin, is a classic example. However,
Jean-Pierre Changeux and colleagues, who used alpha-bungarotoxin to purify
acetylcholine receptors, and William Catterall, who isolated sodium channels
using scorpion toxin, probably did not consider themselves to be
toxicologists. Has modern toxicology actually provided new fundamental
concepts? Surprisingly, with a few notable exceptions, it has not _ it is
nowadays regarded as an applied science that is devoted to minimizing
environmental health risks posed by chemicals, mainly through risk assessment.
- At the same time, there is an emerging crisis of confidence in toxicology
as an applied science that can effectively predict risk, as illustrated by the
debate about servicemen exposed to depleted uranium from weapons during the
Kosovo conflict in 1999. Although there is no evidence for radiological or
chemical carcinogenic risk at any conceivable level of exposure, the wide
perception of this issue has been very different.
Predictions based solely upon epidemiological projections without solid
scientific bases are often misleading. Examples include the debates over
genetically modified foods, dioxins, measles vaccinations, and prion diseases
in cattle and sheep. In the case of prion diseases, there is a remarkably
uncertain and contradictory range of theoretical predictions for the size of
any future epidemic of variant Creutzfeld-Jakob disease in humans.
- There are surely various reasons for this failure of trust, but the
authors discuss one in particular. Perhaps because of the immense scope of
research into the mechanisms by which individual compounds act, basic research
has, over the past two decades, become irrelevant to many toxicologists.
A discipline that mostly depends on others for fresh fundamental knowledge,
and is slow in acquiring it, will also be slow in its progress and weak in its
conclusions. Prejudice, ideology and irrationality will undoubtedly grow.
For instance, few among the public appreciate the fact that hazard and risk
are different concepts. Hazard defines the potential of a compound to cause
harm and is therefore associated with virtually any molecule, whereas a risk
of adverse health effects relates to the level of exposure and to individual
susceptibility to that molecule. Such misunderstanding may account for the
generous public funds that have been allocated to the study of dioxin
toxicity, despite the lack of evidence for effects on human health at current
- Toxicology is being shaped by worldwide political agendas,
triggered by the public's desire for swift and precautionary solutions to the
possible health effects of environmental chemicals. The resulting feedback
loop has impoverished the discipline, because its growth has largely been
driven by the demand for protocols for regulatory actions (1-5).
1. Berry, C. Trends Pharmacol. Sci. 22, 277-280 (2001).
2. Golub, T. R.l. Science 286, 531-537 (1999).
3. Hoeijmakers, J. H. J. Nature 411, 366-374 (2001).
4. Smith, L. L. Trends Pharmacol. Sci. 22, 281-285 (2001).
5. Gibbons, M. Nature 402, C81-C84 (1999).
Nature 2002 416:481