| Science/Tech news |
[Aug. 24th, 2003|02:36 pm] |
Red wine chemical extends life - in yeast
A chemical found in red wine can mimic the life-extending effect of calorie-restricted diets in yeast, researchers have found.
The findings could provide a new explanation for beneficial effects of red wine. And replication of the results in mammals - although still a long way off - would raise hopes that the compound could one day be used to slow age-related diseases in humans.
"Seventy years ago we found that caloric restriction in rats increased lifespan. And over the last 70 years people have been looking for ways to explain it," says lead researcher David Sinclair, at Harvard Medical School in the US. "Now we have shown we can control the longevity pathway with a small molecule."
The compound is a polyphenol called resveratrol, and is found in grapes. Previous research has shown it can protect against heart disease in humans, but whether the life-extending properties it shows on yeast will extend to mammals is unknown. "It's a long way from yeast to humans," says David Finkelstein, at the US National Institute on Aging in Washington DC. "But it points the way to go."
Caloric restriction in yeast activates an enzyme called SIR2, which is thought to extend lifespan by stabilising DNA. Sinclair and his colleagues found a group of polyphenols that activated this gene in yeast and extended the organisms' life. The most potent was resveratrol, which increased average survival time by 70 per cent.
Scientists have suggested that resveratrol acts as an anti-oxidant, mopping up harmful free radicals that damage the cell. But Sinclair found the compound does not have strong antioxidant effects in yeast.
Nanoparticles to pinpoint viruses in body scans
An injection of magnetic nanoparticles into your bloodstream could reveal precisely where harmful viruses are lurking.
The particles are coated with antibodies to a particular virus, so they will form clumps that should be visible on conventional body scans if that virus is present. The team working on the technology, from the Harvard Medical School's Center for Molecular Imaging Research in Charlestown, Massachusetts, have already managed to detect viruses in body fluids and tissue samples.
Scans revealing where virus populations are - HIV, for example, tends to concentrate in the lymph nodes - could help doctors improve treatments. And a scan could reveal whether viruses used in gene therapy to ferry new DNA into patients have actually reached the parts of the body they are intended for - and in sufficient numbers to do any good (Journal of the American Chemical Society, DOI: 10.1021/ ja036409g).
Humans trained to hunger like Pavlov's dogs
Humans can be trained to crave food in response to abstract prompts just like Pavlov's dogs, reveals new research.
But whereas Pavlov's dogs were conditioned to drool at the sound of a bell, Jay Gottfried and colleagues at University College London, UK, trained humans to yearn for vanilla ice cream and peanut butter at the sight of fractal-based computer images.
The team tested 13 ice-cream and peanut-butter lovers. The volunteers were first trained to hunger for the foods at the sight of the abstract fractal images. This took place while the subjects were inside an MRI scanner, allowing their brain activity to be measured.
The conditioning took only eight minutes and was achieved by pumping the odour of ice cream or peanut butter into the subjects' noses while specific images were displayed. "The idea was that by repeatedly pairing the pictures and the odours together, the subjects would learn to make an association between the two items," says Gottfried.
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