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  3. Athletes who cheat by injecting themselves with stored supplies of their own blood might soon be caught out. A revealing trail o

Athletes who cheat by injecting themselves with stored supplies of their own blood might soon be caught out. A revealing trail o

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问题     Athletes who cheat by injecting themselves with stored supplies of their own blood might soon be caught out. A revealing trail of debris could give the game away.
    Most "blood dopers"cheat by injecting themselves with the blood-boosting hormone erythropoietin (EPO),but there have been tests todetect EPOsince 2000. Another way to dope blood is to periodically extract some of your own, store it and re-inject it before competitions. Some professional cyclists are alleged to have done this as part of a doping scandal that emerged in Spain in 2006, called Operacion Puerto. At least one cyclist is still fighting to clear his name.
    Re-injecting stored blood boosts the oxygen supply to muscles. The practice has so far eluded detection but now there might be a way catch out the cheats.
    During storage, red blood cells start to fall apart, generating debris such as the fragments of cell membranes (a cell membrane is the outside envelop of a living cell). Olaf Schumacher of the University of Freiburg in Germany and his colleagues have shown that when stored blood is re-injected, the recipient’s white blood cells prepare to get rid of this sudden tide of debris. They say that these changes on blood cell ’debris’ could betray sportsmen and make cheats detectable. "It’s like someone dumping rubbish in your blood," he says. "When all the rubbish comes at once, there’s lots of activity."
    Schumacher’s team took blood from six non-athletes, stored it for 35 days then re-infused it, taking further blood samples three and four days afterwards. When they analyzed the white blood cells in these samples, genes needed for identifying and disposing of ailing and damaged cells were much more active than usual.
    The gene changes led to the appearance of new proteins on the surface of the white blood cells which could potentially be picked up by antibodies, Schumacher says. He also suggests that antibodies could be created to detect the changes to the surface of red blood cells as well. Schumacher couldn’t say whether such tests would be ready in time for the 2012 Olympics in London. David Cowan, director of the UK Drug Control Centre at King’s College London, says: "The paper is promising, but more work is needed to establish a test that meets the rigorous standards required by sport so as not to falsely accuse an athlete." Schumacher says that one key goal is to make sure these changes only occur due to doping, rather than illness, for example.
According to Paragraph 4, which of the following is true about the debris?
选项 A、The white blood cells are ready to get rid of it all the time.
B、It is the product of red blood cells during blood storage.
C、It could help sports cheats avoid detection.
D、It is fragments of cell membranes.
答案B
解析 判断推理题。第四段第一句提到，在血液储存的过程中，红血球细胞开始分裂，产生出诸如细胞膜碎片之类的残骸。B项符合原文。A项仅仅是在受体注射了被储藏的血液之后才会出现的情况，且all the time没有原文依据；C项与第四段第三句意思相反，debris只会使作弊行为更容易被检测出来；D项过于片面，根据第四段第一句，细胞膜碎片只是debris的一种。
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