Curious George歌词

[00:03.877]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 transfused into any patient.This advance could help avoid blood shortages in the future.
[00:16.339]Don:Wow,that is exciting.But what makes type O blood so special?
[00:20.279]Y:Blood types result from different carbohydrates,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.
[00:42.938]Your immune system recognizes the antigens on your blood as "self",but attack cells with "foreign"antigens.So if you ever need a blood transfusion,it's important that you only receive blood compatible with your own type.
[00:53.989]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 donor blood cells?
[01:04.05]Y:Exactly.But type O is called the "universal donor"since it doesn't have any antigens that would set off the body's defense system.
[01:11.369]A team of Danish scientists has identified enzymes that remove the A and B antigens from blood cells.The enzymes,which were extracted from a bacteria and a fungus,essentially change any donated blood into type O.
[01:25.403]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