首页
登录
职称英语
Every year, 2,000 American lives are saved by the selflessness of others. T
Every year, 2,000 American lives are saved by the selflessness of others. T
游客
2023-11-18
59
管理
问题
Every year, 2,000 American lives are saved by the selflessness of others. These are the bone marrow donors who give the gift of life to patients fighting deadly diseases such as leukemia, lymphoma, and aplastic anemia. That’s the good news. The bad news is that thousands more die each year because not enough people have signed on to the registries that would help the ill find a suitable match for a transplant.
Bone marrow or stem-cell transplants are usually a last resort, intended for those whose illnesses have not responded to traditional treatments such as chemotherapy or radiation. How do they work? We all store a special type of cell in our bone marrow called stem cells. These primitive cells give rise to the three types of blood cells: red, white and platelets. Everyone’s stem cells have certain genetic characteristics or markers that make them unique from others. Despite this uniqueness, there are some shared characteristics between people. This is important, because a patient’s immune system will reject blood or organs received from someone else if they do not share sufficient similarities.
Family members, especially siblings, are always the first to be considered as donors, because there’s a greater chance that the genetic markers on their cells will have enough in common to prevent rejection after transplantation. In many cases, however, a familial match can’t be found and then the search begins for an unrelated donor. These donors typically come from a pool of people who have already signed up on a donor registry in the event that their cells match a needy recipient.
Once the lab has verified a match between donor and recipient, the next phase starts. The patient is given radiation or chemotherapy to kill the unhealthy cells. Healthy cells are harvested from the donor — either extracted from the pelvic bones or taken from the arm in a way that is similar to having blood drawn — and prepared in a laboratory. Once they’re ready, they’re given to the patient through a vein — the same way as one would receive a blood transfusion. Once these transplanted donor cells get settled within the patient’s bone marrow, they make the healthy red blood cells, white blood cells and platelets necessary to support life.
One of the major problems currently faced by transplant centers is that while bonemarrow transplants can cure more than 70 different diseases, there aren’t enough donors on the registry to treat the more than 3,000 patients awaiting transplants. The National Marrow Donor Program, the largest registry in the country, has approximately 4.8 million adult volunteer donors, but that isn’t nearly enough for the thousands who need transplants.
Why isn’t a pool of more than 4 million donors isn’t enough to cover 3,000 needy patients? Here’s the reason: in the vast-majority of cases, finding a suitable match isn’t easy. Because we are unique individuals with a variety of ancestral backgrounds and integration patterns, finding someone similar to us is a major task. In the end, it comes down to a numbers game — the more potential donors listed on the registry, the greater a chance of finding a match, especially for those with unusual genetic characteristics. [br] Who is considered the best donor for bone marrow transplant?
选项
A、Parents.
B、Brothers and sisters.
C、Registered donors.
D、Healthy donors.
答案
B
解析
细节题。文章第三段第一句话指出,为防止出现移植后的排异现象,家庭成员,特别是兄弟姐妹,是骨髓移植的首选捐赠者,因为他们细胞中的遗传标记相同的概率较高。siblings指兄弟姐妹,故B正确。
转载请注明原文地址:http://tihaiku.com/zcyy/3198795.html
相关试题推荐
DuringtheearlyAmericancolonialyears,comwasmoreplentifulthanwheat
JeanWagner’smustenduringcontributiontothestudyofAfro-Americanpoetryis
TheAmericanbabyboomafterthewarmadeunconvincingU.S.advicetopoor
TheAmericanbabyboomafterthewarmadeunconvincingU.S.advicetopoor
TheAmericanbabyboomafterthewarmadeunconvincingU.S.advicetopoor
Tomorroweveningabout20millionAmericanswillbeshown,ontheirtelevis
Tomorroweveningabout20millionAmericanswillbeshown,ontheirtelevis
Tomorroweveningabout20millionAmericanswillbeshown,ontheirtelevis
BenjaminFranklinwasthegreatestearlyAmericanleadernevertobecomep
BenjaminFranklinwasthegreatestearlyAmericanleadernevertobecomep
随机试题
"LostCity"ExploredUsingHigh-SpeedNetworksUnderseaexplora
关于抹灰工程,下列哪一项要求是错误的?()A.凡外墙窗台、窗楣、雨篷、阳台、
28岁,GP,孕31周,从28周开始反复阴道流血,共4次,出血量少于月经量,不伴
随着考试临近,学生心情极度紧张,考试时不能集中注意,无法发挥正常水平,这是一种(
猪苓抗肿瘤的主要成分是A:猪苓酸AB:猪苓多糖C:猪苓酸CD:角甾醇E:
前列腺液检查见到白细胞、前列腺颗粒细胞明显增多、红细胞轻度增高,卵磷脂小体消失,
各年累计()不出现负值是财务生存的必要条件。A:资本公积 B:盈余资金 C
女,39岁。因黑色稀便3天入院。3天来,每日排黑色稀便2次,每次约200g,病前
其实,我们每个人的生命最初都是一片光秃秃的土地。只是后来,在我们经历了许多物事之
男孩,已能独坐稳,头围44cm,前囟0.5cm×0.8cm,乳牙3颗。最可能的年
最新回复
(
0
)