Blood type(血型揭秘)

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(抗原), 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.

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

参考例句：

• He transfused his own courage into his men. 他用自己的勇气鼓舞了士兵。 来自《现代英汉综合大词典》
• The professor transfused his enthusiasm for research into his students. 教授把自己的研究热忱移注给学生。 来自辞典例句

2 carbohydrates   

n.碳水化合物，糖类( carbohydrate的名词复数 )；淀粉质或糖类食物

参考例句：

• The plant uses the carbohydrates to make cellulose. 植物用碳水化合物制造纤维素。 来自《简明英汉词典》
• All carbohydrates originate from plants. 所有的碳水化合物均来自植物。 来自辞典例句

3 transfusion   

n.输血，输液

参考例句：

• She soon came to her senses after a blood transfusion.输血后不久她就苏醒了。
• The doctor kept him alive by a blood transfusion.医生靠输血使他仍然活着。

4 donor   

n.捐献者；赠送人；(组织、器官等的)供体

参考例句：

• In these cases,the recipient usually takes care of the donor afterwards.在这类情况下，接受捐献者以后通常会照顾捐赠者。
• The Doctor transplanted the donor's heart to Mike's chest cavity.医生将捐赠者的心脏移植进麦克的胸腔。

5 defense   

n.防御，保卫；[pl.]防务工事；辩护，答辩

参考例句：

• The accused has the right to defense.被告人有权获得辩护。
• The war has impacted the area with military and defense workers.战争使那个地区挤满了军队和防御工程人员。

6 enzymes   

n. 酶，酵素

参考例句：

• It was said that washing powders containing enzymes remove stains more efficiently. 据说加酶洗衣粉除污更有效。
• Among the enzymes which are particularly effective are pepsin, papain. 在酶当中特别有效的是胃朊酶、木瓜酶。

7 fungus   

n.真菌，真菌类植物

参考例句：

• Mushrooms are a type of fungus.蘑菇是一种真菌。
• This fungus can just be detected by the unaided eye.这种真菌只用肉眼就能检查出。

8 essentially   

adv.本质上，实质上，基本上

参考例句：

• Really great men are essentially modest.真正的伟人大都很谦虚。
• She is an essentially selfish person.她本质上是个自私自利的人。