英语听力文摘 English Digest 327、吸血蝙蝠能挽救生命？（在线收听）
Bat Spit
蝙蝠的唾液
Anyone who reads gothic fiction will tell you that vampires are bad news. People who read modern medical journals, however, might disagree–in fact, they think vampires just might help save lives.
The kind of vampire I’m talking about is Desmodus rotundus, commonly known as the “vampire bat.” Yep, these little creatures are real; and even though they almost never turn into suave Romanian counts to drool over, they do drool a lot themselves. That’s because their saliva is an essential part of their dining habits.
When a vampire bat latches onto, say, a steer, it needs to keep the blood flowing from the puncture made by its teeth. That’s achieved by a natural anti-coagulant in the vampire bat’s saliva. Despite what you see in the movies, vampire bats almost never drink human blood. But people do suffer from other blood problems–a leading one being stroke.
Stroke is caused by a clotting in the blood which stops the flow and can starve areas of the brain of oxygen. Doctors have generally broken up clots with a compound called tPA. TPA works okay, but it has dangerous side effects, and can even hurt brain cells.
A better idea? Bring in the bats, says researcher Robert Medcalf, a biochemist from Australia. Vampire bat spit contains a different compound, DSPA, which does the good things tPA does with far fewer side-effects. DSPA is now being tried on patients who have suffered a stroke; the data should be in within a year. If it works, doctors might have found an unlikely friend–the vampire bat.
读过哥特小说的人都会说吸血蝙蝠是个讨厌的东西。而那些读现代医学杂志的人也许不同意这样的观点，他们认为吸血蝠能帮助拯救生命。
我说的是圆形叶口蝠，俗称“吸血蝙蝠”。是的，这些小家伙是真实的，尽管它们几乎没有垂涎于温雅的罗马利亚人，但它们却经常流口水，因为唾液是它们饮食习惯中的必不可少的一部分。
当吸血蝙蝠缠在，比如一直公牛身上时，必须保持血液从牙齿咬开的孔流过。这是通过蝙蝠唾液里一种天然的抗凝血剂来实现的。尽管你会在电影里看到，吸血蝙蝠几乎从来不吸人的血。但人类患有其它血液疾病——最重要的就是中风。
中风是由于血液凝结成块阻碍其流动，从而导致大脑部分缺氧。医生们已经找到了分解血液凝块的化合物，就是tPA。TPA很有效，但具有危险的副作用，甚至会损伤脑细胞。
有更好的主意吗？澳大利亚生物化学家，Robert Medcalf对蝙蝠进行研究。吸血蝙蝠的唾液中含有一种不同的化合物，DSPA，它能够帮助减少tPA引起的副作用，DSPA现在正在患有中风病人身上测试，结果将于一年内揭晓。如果有效的话，医生们也许多一位意想不到的朋友——吸血蝙蝠。