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Yael: I just read about an exciting technique. Researchers found a way to convert types A and B blood into type O blood--the type that can be transfused1 into any patient. This advance could help avoid blood shortages in the future.
Don: Wow, that is exciting. But what makes type O blood so special?
Y: Blood types result from different carbohydrates2, called antigens, on the surface of human blood cells. Your blood "type" denotes the kinds of antigens you have on the surface of your cells. People with type A blood have A antigens; those with type B have B antigens. If you have both kinds of antigens, you're type AB; if you have neither one, you're type O.
Your immune system recognizes the antigens on your blood as "self", but attack cells with "foreign" antigens. So if you ever need a blood transfusion3, it's important that you only receive blood compatible with your own type.
D: I see. So if a type A person receives type B or AB blood, her immune system will see the B-antigens as foreign, and attack the donor4 blood cells?
Y: Exactly. But type O is called the "universal donor" since it doesn't have any antigens that would set off the body's defense5 system.
A team of Danish scientists has identified enzymes6 that remove the A and B antigens from blood cells. The enzymes, which were extracted from a bacteria and a fungus7, essentially8 change any donated blood into type O.
Clinical trials are underway to test whether the treated blood is safe and effective. If so, the technology could help save lives, since type O blood is such a precious commodity.
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1 transfused | |
v.输(血或别的液体)( transfuse的过去式和过去分词 );渗透;使…被灌输或传达 | |
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2 carbohydrates | |
n.碳水化合物,糖类( carbohydrate的名词复数 );淀粉质或糖类食物 | |
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3 transfusion | |
n.输血,输液 | |
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4 donor | |
n.捐献者;赠送人;(组织、器官等的)供体 | |
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5 defense | |
n.防御,保卫;[pl.]防务工事;辩护,答辩 | |
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6 enzymes | |
n. 酶,酵素 | |
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7 fungus | |
n.真菌,真菌类植物 | |
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8 essentially | |
adv.本质上,实质上,基本上 | |
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