Scientists perform fewer experiments on animals than they have for 30 years. But plans to transplant pig hearts into chimpanzees (box) are likely to inflame animal rights protesters. Alison Goddard reports

In some British labs, the beating hearts of sedated guinea pigs are torn out in science's name. By studying the organs, researchers hope to learn how the heart works and, ultimately, how to cure human heart disease.

Do scientists have to experiment on animals?

Animal-rights activists say no, scientists, yes. The argument has raged for years.

Last week at the British Association's annual meeting in Cardiff anti-vivisectionists confronted biomedical researchers in a debate over "To what extent can we replace the use of animals in biomedical research?".

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John Martin of the Wolfson Institute for Biomedical Research in London was one of the speakers in the debate. He disputed "the uneducated and simplistic view" that human disease can be cured without using animals. "I don't see any possibility of that in the next 100 years," he said.

Martin's research explores how heart attacks occur, and animals are vital for a fraction of his work. Tissue cultures change over time, and Martin has been misled by some results from human tissue culture. Similarly, computer modelling of how blood cells stick to each other has also yielded incorrect results that were revealed only by subsequent animal experiments. "I believe that animals are valuable and that humans are valuable, and that humans are more valuable than animals," he argues.

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It is a point with which some anti-vivisectionists have sympathy. The British Union for the Abolition of Vivisection campaigns for a complete end to the use of animal testing but takes a pragmatic view in the short term. "I feel that there is a new consensus on practical ways of moving away from the use of animals," says Mike Baker, BUAV chief executive. "There are ways of moving forward on this without damaging biomedical research. For example, the link between smoking and lung cancer was made through epidemiological studies." That finding was replicated only after observing beagles that had been forced to inhale cigarette smoke for years.

Not long before the BA's meeting, more than 1,000 scientists, including 31 Nobel laureates, had signed a declaration stating that experiments on animals have contributed to great medical advances. More research using animals is essential, the declaration goes on, to conquer unsolved medical problems such as cancer and Aids.

The declaration warns that violent attacks on people and property, and hostile campaigns against individual scientists should be publicly condemned. Scientists such as Oxford physiologist Colin Blakemore, whose research into vision has involved sewing shut kittens' eyelids, have received letter bombs. Others have been too scared to make their work known publicly.

According to the É«ºÐÖ±²¥ Office, some 2.64 million experiments were conducted on animals last year, fewer than at any time in the past 30 years. And, it says, it has issued no licences for cosmetics testing on animals since a voluntary industry-wide ban came into force in November 1997.

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To encourage the move away from animal testing, researchers at the European Centre for the Validication of Alternative Methods are creating a database of alternatives, which they plan to put on the Web.

As animal welfare groups fund research into the issue, alternatives are set to multiply. The Dr Hadwen Trust, which funds 25 projects, hopes to spend up to Pounds 250,000 on university-based research next year. One of the projects is the human tissue bank at the University of Leicester. It stores and distributes donated human organs that were removed for transplant into humans but then found to be unsuitable. "The bank aims to provide scientists with a reliable source of human tissues, to replace animal research in the fight to save human lives," says Terry Huxtable, trust secretary.

Number of experiments using animals

.......................................1995 1996 1997

Primates............................. 4,721 4,374 3,908

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Genetically manipulated animals..... 215,000 302,000 353,000

All animals (total)............... 2,710,000 2,720,000 2,640,000

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