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International Association Against Painful Experiments on Animals

Fatal Mistakes of Animal Experiments Testing

6: Animal Tumours So Different that Similarity in Results Seem Coincidental

component of anti-cancer drug treatments but fails to work in a range of animal tumours, some of which were once used by America’s National Cancer Institute to identify promising new drugs!25

Some animal tumours are so different to their human counterparts that any similarity in results seems coincidental. A widely used animal model of breast cancer is the mouse in which disease is induced by a virus. But human breast cancer is not caused by a virus and whilst early pregnancy can reduce the risk of illness in women, the opposite is true in mice. Again, mouse breast tumours seldom spread whereas this is a characteristic of the human disease. Animal researchers concede that ‘the mouse model . . . has important differences from breast cancer in women.’26

Animal models have often produced disastrous results for human medicine. The use of monkeys in malaria research led to the suggestion that steroids would help patients who developed coma. But human trials showed that steroids are actually dangerous, prolonging coma and increasing the risk of complications.16 In an experimental model of heart failure in rats, the drug milrinone improved both cardiovascular performance and survival. Administration to patients, however, led to more hospitalisations and cardiovascular side-effects, together with a 28% increase in death rate.27 On the basis of animal experiments, high doses of corticosteriods were recommended for the treatment of septic shock but clinical trials revealed they were both ineffective and potentially fatal.16 The value of bicarbonate for methanol poisoning was doubted for over 30 years because it not only failed in animals but generally proved toxic to them.28 And attempts to prevent the lung disease silicosis by inhaling aluminium dust had to be abandoned after studies of workers showed it was useless and could be dangerous. The procedure originated from experiments with rabbits.16

Similar problems can arise in surgical research. The use of the patient’s own veins for surgical repair of diseased arteries was delayed through animal experiments which wrongly suggested there would be serious side-effects: vein grafts had been clinically tested during World War II and the Korean War but despite comparatively successful results, the techniques were discredited following tests on animals.29 The development of artificial heart valves was also held back because of experiments on animals. The valves almost always produced fatal blood clots in dogs and this deterred many surgeons from carrying our human trials.16 Eventually experimental surgeons Starr and Edwards boldly decided on a ‘caged ball’ device and although this killed most of the test animals, it proved successful in clinical trials where blood clotting was not such a problem. They concluded that ‘the marked propensity of the dog to thrombotic occlusion [blood clotting] or massive embolization from a mitral prosthesis is not shared by the human being.’16

In another example, surgeons proceeded with the first human kidney transplants even though the results from animal experiments were discouraging. British transplant surgeon and animal researcher Roy Calne explains that, ‘Despite no serious attempts at immuno-suppression, apart from >>

 

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