Science: Update

A CLOT-BUSTING drug to treat heart patients is to be developed from snake venom in an pounds 84,000 study funded by the British Heart Foundation. A molecule in venom called dendroaspin (or mambin) is known to stop blood from clotting - which can prevent strokes - but causes side-effects. The study points the way to drugs based on the anti-clotting part of dendroaspin, which does not produce associated problems.

Dr Eve Hyde, a scientist at the University of Birmingham, where the research is to be carried out, said: "We have already found out the overall structure of dendroaspin, but now we hope to focus in on a part of the molecule that makes it so effective at stopping clots. If we can find this part and copy it, it could be the basis for a highly effective new drug."

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SCIENTISTS AT the American National Aeronautics and Space Administration (Nasa) are expected next week to announce new evidence for the presence of life on Martian meteorites. Researchers led by David McKay, from Nasa's Johnson Space Center in Houston, will inform the Lunar and Planetary Conference that they have found tiny structures on the Nakhla meteorite that could be fossilised micro-organisms. The same group said in 1996 that they had found signs of life on another meteorite, known as ALH84001, but this was subsequently disputed by other scientists. Critics argue that the meteorites have suffered too much terrestrial contamination to be of use in the search for Martian life forms.

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VIAGRA, THE wonder drug for male impotence, does not have the same effect on women, reports New Scientist. A study of 33 post-menopausal women in the US found that only a quarter of them claimed their sex lives had improved as a result of taking the drug - results which were no better than a placebo. Steven Kaplan, of the Columbia University College of Physicians and Surgeons in New York, said that only one in five of the women wanted to continue taking Viagra after the trial. "Clitoral blood-flow improvement, manifested... by increased sensitivity, may not have translated into improved sexual function," Dr Kaplan said.