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Podcast TranscriptThe Naked Scientists: Science Radio & Science Podcasts |
| 18th May 2002 | < Previous Show | Next Show > | ||||||||||
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Mechanical Leeches Helping Surgeons
Here's something slimey. Real leeches are used by surgeons because arteries are easier to re-connect than the more fragile veins, making it easier for blood to get into the tissue than to get out. This means a reattached finger often swells up with blood, which coagulates, clots and prevents the finger grafting properly. Leeches can be useful because they inject a bit of saliva containing their own anticoagulant, called hirudin, and then feed off the excess blood which helps to keep a constant supply of fresh blood flowing into the tissues. The process is painless but patients and doctors often dislike the idea of touching the slimy creatures. Help is at hand in the form of a newly invented mechanical leech. The little device is based on a vacuum pump and unlike leeches will be sterile, and will not get tired or full up ! The University of Wisconsin team involved and says the artificial bloodsucker consists of a glass shell that fits over the skin and a vacuum to draw off blood. A slender rotating probe pierces the skin and infuses a mixture of the anticoagulant heparin and polyvinyl alcohol to keep the blood flowing. The mechanical leech has certain advantages too. Up to 20 per cent of patients treated with real leeches develop infections caused by Aeromonas hydrophila, bacteria that live in the leech's gut. These infections can be treated with antibiotics, but Conforti says that his device would be sterile. And while leeches stop feeding when sated, their mechanical counterparts will go on removing blood for as long as needed. Finally, the mechanical leech's probe can be adjusted to go deep into the tissue if clotted blood collected there- real leeches just attach to the surface and suck....
18th May 2002
Male Starlings Sing a Song of Reproductive Fitness
Scientists at Johns Hopkins in the US have found that how well a male Starling sings is a strong indication of the health of his immune system and hence his suitability as a mate. Dr. Duffy and Dr. Ball looked at the singing abilities of 16 adult male European Starlings in an outdoor aviary. They compared the strengths' of their immune systems with how many songs they sang, and how long each song was. They found that they best singers also had the best immune systems. Presumably female Starlings pay a lot of attention to singing because it indicates a healthy mate who is likely to father healthy chicks. How the link between immunity and song quality comes about though, we don't know, but as the researchers point out, it might provide important clues to how the immune system is controlled at large which has implications for many diseases in animals and people.
18th May 2002
Wind Farms - Great Idea Under Threat From the Mod
Britain's plans to generate 10% of electricity from renewable sources could be under threat from an unlikely source…the Ministry of Defence. They have blocked plans for five of the proposed eighteen new offshore windfarms. Apparently wind turbines show up as a twinkling spot on radar screens, making aircraft hard to track. And the turbines may even cause a radar shadow behind them, so that wind farms could be used as a camouflage for enemy aircraft.
18th May 2002
New Information About Oetzi
The archaeologists studying Oetzi, the stone age man found frozen in ice in the Alps, have made an interesting discovery, a flint arrowhead lodged in his shoulder. Many experts have speculated how the man came to be where he was found, but this recent discovery suggests that he had probably fled an attacker before finally bleeding to death. That he was involved in violent combat not long before his death seems likely since the teams studying his remains have also found a deep wound on his right hand.
18th May 2002
Coffee Protects your Teeth
Many people think that coffee is bad for your teeth, but recent research has shown that the reverse may be true. Coffee made from roasted coffee beans contains substances with antibacterial effects against Streptococcus mutans, a bacterial strain which inhabits the mouth and causes caries, or dental decay.
Coffee prevents colon cancer
GM strawberries to tackle tooth decay
18th May 2002
Termite Vaccination Programme
Humans aren't the only ones with a vaccination programme, apparently. James Traniello and his team at Boston University in the US have found that termites vaccinate their nest-mates, protecting them against diseases that, unchecked, would wipe out their colony. Other social-animals have similar strategies for controlling infections within their numbers. For instance ants remove dead workers from their nests, whilst bees increase the temperature in parts of their hives infected with fungi to stop the invading organism from growing properly. So what do the termites do ? The Boston scientists have found that if they infected some termites with a fungal disease, allowed them to recover, and then introduced them to a group of termites that had never had the fungal disease, these new 'unexposed' termites fared much better than termites that had not previously mixed with survivors of the disease. The team are calling this 'social vaccination', although they are not sure how the termites are sharing immunity to the infection amongst their nest mates. Termites regularly share gut-bacteria with each other to enable them to digest food, so they could be sharing strains of bacteria that naturally make fungicides. Alternatively, immunised termites might be passing dead fungal 'spores' to each other, so that they can experience the infection safely, rather like injecting dead viruses or bacteria into a person to make them immune.
18th May 2002
Another Secret to Smooth Ice-cream
We've all had ice cream that was crunchy. The reason is that with repeated thawing and re-freezing as happens when you take the tub out of the deep-freeze, the ice crystals grow too large and the smooth silky texture is lost. But scientist Douglas Goff from Guelph University, Canada, has identified a natural 'anti-freeze' protein, produced by wheat plants to help them resist freezing in the winter. The team have been extracting the protein from wheat seedlings and adding it to ice-cream to test the effects. The team suggest that this is a vegetarian-friendly way to make smooth ice-cream. Other attempts to keep ice-cream soft have included using proteins extracted from Arctic fish, and a bacterial protein marinomonin, isolated last year from bacteria inhabiting Antarctic lakes.
18th May 2002
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Can people with no vocal cords still snore ? Jane, by email, |
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Yes, because snoring is produced by the soft palate falling to the back of the throat and vibrating. It doesn't come from the vocal cords. |
May 2002 |
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What is cellulite - I can find lots of claimed 'cures', but no information about what it actually is ? Anon |
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Cellulite is nothing more than just a localised collection of fat. The dimpled appearence is produced by the fat bulging out between the fibrous tissue and is merely a reflection on the normal female fat distribution. |
May 2002 |
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Why do mints make your breath feel cold ? James, by email, |
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According to a group of scientists in San Francisco, the reason is that the same nerve fibres that signal hot and cold are also sensitive to menthol, an ingredient in mints. Normally when the temperature changes it causes pores on the surface of the nerve cell to open and close, changing the electrical activity of the cell, which the brain interprets as a change in temperature. But menthol can also affect the function of the pores in the same way and triggers the nerve cell into thinking that the temperature is lower than it is. |
May 2002 |
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