From Anthrax Vaccine to Aids Drugs, Testing is Set to Continue - For Now The great geneticist JBS Haldane once complained that his wife was encouraged by the government and press to poison rats with phosphorus. He on the other hand had to get the signature of the president of the Royal Society, and another leading scientist, then apply to the home secretary "before I can even kill a mouse in a slightly novel manner". That was in 1927. More than 70 years on, bureaucracy is still an issue but according to drug companies, biochemists, researchers, neuroscientists and geneticists the need for animal experiments is as great as ever. The two worlds, however, are not strictly comparable. Then, in an essay entitled "Some enemies of science", Haldane could pillory the hypocrisy of fox-hunting peers who introduced bills to prohibit animal experiments. Now hunters are under pressure too, and public attitudes have changed profoundly. In the scientific community there has been debate for years. Opponents have argued that many animal experiments have produced misleading results. In the 60s, tobacco firms could claim tobacco smoke did not cause cancer, because it did not cause lung cancer in rodents. A drug company scientist pointed out that of the 19 chemicals known to cause cancer in humans, only seven caused cancer in rodents. A heart drug that was highly effective on rats turned out to increase the chance of death for a human cardiac patient. The technology moved on, too. Many scientists, having learned what they could from living creatures, moved on to see what drugs did to cells cultured in petri dishes, with sometimes more precise results. Epidemiology - the study of what happens to populations over decades - began to show a clearer picture of factors in cancer, heart disease and diabetes. Drug firms are already talking of computer-based experiments to come, modelling how a virtual drug will behave in a virtual human. But proponents counter that without animals, Louis Pasteur would not have developed his anthrax vaccine, and Joseph Lister could not have developed antiseptic treatments that have saved millions of lives. Animals in this century died necessarily in the development of heart surgery, hypertension treatments, anti-ulcer drugs and organ transplants. Now the battle is stepping up: the human genome project has unravelled human DNA and detected genes linked to cancer, diabetes and transplant rejection. But biologists still have to work out precisely what these genes, and their proteins, actually do. More knowledge, they argue, will mean more experiments, for a time. Scientists argue that most experiments are strictly controlled, and involve very little pain, and that some tests are anyway in the service of animal welfare rather than human health. The public - though largely prepared to tolerate intensive farming for the sake of cheap meat - is uneasy about the idea of animal experiments, but also in favour of new treatments for disease. A Mori poll for New Scientist last year found that when asked: "should scientists experiment on animals" 24% were in favour, 64% against. But this clarity disappeared if pollsters prefaced the question with a statement that scientists believed the experiments would speed up research into treatments for Aids or leukaemia or better painkilling drugs. Then 45% approved of the experiments, 41% were against. In the lab Mouse protection test Used to test toxicity of antibiotics. Involves giving the antibiotic to three species - usually a mouse, a rat and a large animal like a rabbit or a dog. If all three suffer no ill effects, the antibiotic is likely to be safe in humans; if all three are poisoned, it is too dangerous. Sometimes only one species is affected, which means further tests are needed Raising antibodies An animal is injected with a substance. A week later, the same animal has a further injection of the same substance. The animal's immune system responds by producing antibodies, which can be purified from its blood, analysed and used for further research An animal, usually either bred or genetically engineered to simulate a human illness, will be given a medicine and studied to see if it has the desired effect. For a drug to combat high blood pressure, for instance, researchers would probably use a species of rat called a "spontaneously hypertensive rat." There are mice bred to test treatments for numerous human ailments - Alzheimer's mice, muscular dystrophy mice, cancerous mice, obese mice, bald mice Gene hunting Used in mutated or "knockout" animals, which have had genes altered or knocked out, when it is not known which genes have been removed or what they do. The animals, usually mice, are subjected to dozens of tests of strength, stamina, intelligence and metabolism Autopsy Often used as the culmination of other experiments. The animal is killed using an overdose of anaesthetics and its inner organs examined Brain experiments Often used in fundamental research, where medical relevance is unclear. Scientists at Oxford in 1998 and Cambridge in 1999 trained monkeys to respond to stimuli in certain ways, then chemically damaged areas of their brains to see how their performance changed. In 1999, Bristol researchers implanted microscopic wires into the brains of cats, then electrically stimulated the nerves in their legs, to see how their brains responded Source: Tim Radford, science editor Tuesday July 4, 2000 The Guardian http://www.guardian.co.uk/ Guardian Unlimited © Guardian Newspapers Limited 2002