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  3. 共用题干 第一篇Human Heart can Make New CellsS

共用题干 第一篇Human Heart can Make New CellsS

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问题 共用题干第一篇

Human Heart can Make New Cells

Solving a longstanding（为时甚久的）mystery, scientists have found that the human heart continues to
generate new cardiac（心脏的）cells throughout the life span, although the rate of new cell production slows
with age.
The finding,published in the April 3rd issue of Science,could open a new path for the treatment of heart
diseases such as heart failure and heart attack,experts say.
"We find that the beating cells in the heart, cardiomyocytes（心肌细胞）,are renewed," said lead
researcher Dr. Jonas Frisen,a professor of stem cell research at the Karolinska Institute in Stockholm,
Sweden."It has previously not been known whether we were limited to the cardiomyocytes we were born with
or whether they could be renewed,"he said.
"The process of renewing these cells changes over time,"Frisen added. In a 20-year-old,about 1
percent of cardiomyocytes are exchanged each year , but the turnover（更替）rate decreases with age to only
0.45 percent by age 75.
"If we can understand how the generation of new cardiomyocytes is regulated,it may be potentially
possible to develop pharmaceuticals（药物）that promote this process to stimulate regeneration after , for
example,a heart attack,"Frisen said.
That could lead to treatment that helps restore damaged hearts.
"A lot of people suffer from chronic heart failure,."noted co-author Dr. Ratan Bhardwaj,also from the
Karolinska Institute."Chronic heart failure arises from heart cells dying," he said.
"With this finding,scientists are opening the door to potential therapies（疗法）,to having ourselves heal
ourselves,"Bhardwaj said."Maybe one could devise a pharmaceutical agent that would make heart cells
make new and more cells to overcome the problem they are facing."
But barriers remain.According to Bhardwaj,scientists do not yet know how to increase heart cell
production to a rate that would replace cells faster than they are dying off,especially in older patients with
heart failure.In addition,the number of new cells the heart produces was estimated using healthy hearts一
whether the rate of cell turnover in diseased hearts is the same remains unknown.In people in their mid-70s,only 0.45 percent of cardiomyocytes______.A:are still functionalB:are reduced each yearC:are replaced each yearD:are damaged each year
选项 In people in their mid-70s,only 0.45 percent of cardiomyocytes______.
A:are still functional
B:are reduced each year
C:are replaced each year
D:are damaged each year
答案 C
解析 根据第一段中“…the human heart continues to generate new cardiac（心脏的）cells throughout the life span”可知，在人的整个生命进程中，其心脏持续产生新的心肌细胞。言外之 意，这个过程直到生命结束才会停止。
根据第二段中“The finding...could open a new path for the treatment of heart diseases”可 知，这个研究成果将为心脏病的治疗开辟新的途径。因此C项符合题意。
根据第四段中“…but the turnover（更替）rate decreases with age to only 0.45 percent by age 75”可知，C项符合题意。
根据倒数第三段中“Chronic heart failure arises from heart cells dying”可知，慢性心力衰 竭是由心肌细胞死亡导致的。因此A项符合题意。
最后一句的大意是：另外，心脏产生的新细胞的数量是按照健康心脏估算的，而患病心脏的细胞更替率是否与健康心脏相同还不得而知。因此C项符合题意。第二篇 本篇文章主要讲述了远古冰人尸体的发现及对其的相关研究情况。
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