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Unformatted text preview: T he use of animals for research and testing is only one of many investigative techniques avail- able. We believe that although animal experiments are sometimes intellectual- ly seductive, they are poorly suited to addressing the urgent health problems of our era, such as heart disease, cancer, stroke, AIDS and birth defects. Even worse, animal experiments can mislead researchers or even contribute to illness- es or deaths by failing to predict the tox- ic effects of drugs. Fortunately, other, more reliable methods that represent a far better investment of research funds can be employed. The process of scientific discovery of- ten begins with unexpected observations that force researchers to reconsider ex- isting theories and to conceive hypothe- ses that better explain their findings. Many of the apparent anomalies seen in animal experiments, however, merely reflect the unique biology of the species being studied, the unnatural means by which the disease was induced or the stressful environment of the laboratory. Such irregularities are irrelevant to hu- man pathology, and testing hypotheses derived from these observations wastes considerable time and money. The majority of animals in laborato- ries are used as so-called animal mod- els: through genetic manipulation, sur- gical intervention or injection of foreign substances, researchers produce ailments in these animals that “model” human conditions. This research paradigm is fraught with difficulties, however. Evo- lutionary pressures have resulted in in- numerable subtle, but significant, dif- ferences between species. Each species has multiple systems of organs—the car- diovascular and nervous systems, for example—that have complex interac- tions with one another. A stimulus ap- plied to one particular organ system perturbs the animal’s overall physiolog- ical functioning in myriad ways that of- ten cannot be predicted or fully under- stood. Such uncertainty severely under- mines the extrapolation of animal data to other species, including humans. Animal Tests Are Inapplicable I mportant medical advances have been delayed because of misleading results derived from animal experiments. David Wiebers and his colleagues at the Mayo Clinic, writing in the journal Stroke in 1990, described a study showing that of the 25 compounds that reduced dam- age from ischemic stroke (caused by lack of blood flow to the brain) in rodents, cats and other animals, none proved ef- ficacious in human trials. The research- ers attributed the disappointing results to disparities between how strokes nat- urally occur in humans and how they were experimentally triggered in the an- imals. For instance, a healthy animal that experiences a sudden stroke does not undergo the slowly progressive ar- terial damage that usually plays a cru- cial role in human strokes....
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This note was uploaded on 06/18/2008 for the course LS 2 taught by Professor Pires during the Spring '08 term at UCLA.
- Spring '08