|
|
Issue 285, Friday 25 January 2013 - 13 Rabi' al-Awwal 1434 Health and Science By Rachel Kayani Breath tests could be used to identify lung diseases A new breath-test could detect bacterial lung infections, like tuberculosis, within minutes dramatically reducing waiting times for laboratory tests, which can take days to complete. Bacteria that cause lung infections release volatile organic compounds that can be detected in exhaled breath. Scientists hope that by identifying these unique chemicals, or ‘chemical fingerprints’, given off by different bacteria they can analyse a patient’s breath to determine which bacteria is responsible for a particular lung infection. The correct medication and antibiotic can then be started more promptly to help target the infection. Researchers from the University of Vermont in the US have published a study showing that they were able to analyse and identify volatile organic compounds (VOCs) given off from different bacteria in exhaled breath, as well as different strains of the same bacterium. Currently, correctly identifying which bacteria is responsible for a lung infection can takes days if not weeks. Firstly, a sample has to be taken; this is then used to grow a colony of bacteria in the lab. Then tests need to be carried out to determine what class of bacteria is present, and which antibiotics it is resistant to, before treatment can begin. A breath test could potentially speed up this process and it is less invasive. The method they used to test for volatile organic compounds is called Secondary Electrospray Ionization Mass Spectrometry (SESI-MS). It can find minute traces of such compounds, down to one part per trillion. Breath analysis is a new and emerging field and this technique is also being applied to other conditions of the lung - such as asthma and cancer. It is hoped it will open up new diagnostic tests that can significantly help in the treatment of patients with a range of lung diseases. Why do our fingers go wrinkly when wet? Sit in the bath for too long and we all know what happens – wrinkly fingers. It happens to all of us when our hands and feet are submerged in water for any length of time – but what we don’t really know is why this happens. Scientists from Newcastle University have now come up with a possible explanation for our prune like fingers and toes when we get wet – it helps to improve your grip on wet objects. For a long time, the wrinkly skin effect seen on our fingers and toes after being submerged in water was thought to be the result of the skin swelling in water, but recent investigations have actually shown the furrows to be caused by the blood vessels constricting in reaction to the water. Constricting the vessels in this way is a response that is controlled by the nervous system – in this case the sympathetic nervous system, which plays a role in regulating blood pressure and vessel diameter in the body. Given that an active system of regulation is involved, scientist began to think the ridges and furrows in the skin could have a function. American based researchers were the first to propose that the wrinkles might act like the tread on tyres, and even demonstrated how the patterns in the skin resembled those of run-off channels seen on the sides of hills. To test if the wrinkles gave better grip when handling objects with wet hands, the team in Newcastle asked volunteers to pick up marbles immersed in a bucket of water with one hand, then passing them through a small slot to be deposited by the other hand in a second container. They found that volunteers with wrinkled fingers routinely completed the task faster than the group with smooth skinned fingers. The team also found that there was no advantage from having wrinkly skin when handling dry objects - but it did seem to confer an advantage when handling wet objects, and provided a better grip under water, suggesting that the wrinkles serve the specific function of improving our grip on objects under water or when dealing with wet surfaces in general. The team have suggested that this adaptation to the wet, and when we are handling wet objects, may have been of particular benefit to early man as he foraged for food along lakes and shore-lines and by rivers. Wrinkled feet would have provided better grip when walking in water or wet conditions, and on the fingers better grip when handling or searching for foods and materials in water. Exactly how the wrinkles offer greater grip is unclear – it could be the grooves help to channel the water away improving grip – the scientists hope to look at this next. Rachel Kayani |
|