- 相关推荐
2013职称英语卫生类B试题解析（3）
Human Heart Can Make New Cells
Solving a longstanding mystery, scientists have found that the human heart continues to generate new cardiac cells throughout the life span, although the rate of new cell production slows with age.
The finding, published in the April 3 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, 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 are bom with or if 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 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 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.
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 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-whether the rate of cell tumover in diseased hearts is the same remains unknown.
1. The human heart stops producing cardiac cells
A. when a person becomes old
B. as soon as a person gets sick
C. immediately after a person is born
D. once a person dies
2. The finding could prove to be useful to
A. the analysis of cardiac cells
B. the prevention of chronic diseases
C. the treatment of heart disease
D. the study of longstanding mysteries
3. 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
4. Chronic heart failure is attributed to
A. the dying heart cells
B. the effect of pharmceutical
C. the weight of a patient
D. the life span of a person
5. It is not known yet if the rate of cell turnover in diseased hearts
A. is high enough to replace cells faster than they're dying off
B. is of any use to researchers
C. is the same as that in healthy hearts
D. changes over time
参考译文及答案：
帕金森氏综合征
帕金森氏综合征会影响你行动的方式。当大脑的某些神经细胞出现问题时，这种疾病就会爆发。正常情况下，这些神经细胞会产生一种叫多巴胺的重要的化学物质。多巴胺会向你的大脑中控制行为的部分发出信号。它使你的肌肉能活动自如，做你想做的事。一旦你患上帕金森氏综合征，这些神经细胞就会出问题。接着，你不再有足够的多巴胺，并开始行动困难。
没人知道什么促使这些神经细胞出现问题。但是，科学家们做了很多研究来寻找答案。
他们研究了很多可能的病因，包括年龄老化和环境污染。在某些人身上，似乎是不正常的基因导致了帕金森氏综合征的发病。但是目前没有足够的证据表明它是遗传的。
颤抖可能是你注意到的第一个症状。虽然并不是每一位患者都有这种症状，但是它是这种疾病最常见的表现之一。更重要的是，并不是每一个颤抖的人都患有帕金森氏综合征。颤抖往往从一条胳膊，一条腿或身体的一侧开始。这种情况在你醒着但是没有移动受影响的胳膊或者腿时更严重些。但是当你移动肢体或睡眠时情况会有所缓和。不久，帕金森氏综合征会影响你的全身肌肉，导致吞咽困难及便秘。在疾病后期，患这种病的人可能会有表情僵化，言语困难及其他一些问题。一些患者也会思维退化。
现在还没有办法治愈帕金森氏综合征。但是有几种药物能控制症状并让患者好受些。如果你的症状很轻微的话，你可能根本不需要治疗。直到你的症状影响到你的日常生活方式时，医生才会给你开药。伴随着你的症状的恶化，医生将会调整用药。为了得到最好的疗效你得吃几种药。
1.D [解析]根据是第一段中：…the human heart continues to generate new cardiac cells throughout the life span。在人的整个生命进程中，其心脏不时产生新的心肌细胞。言外之意，这个过程直到人死才会停止。
2.C [解析]根据是第二段中：The finding，…，could open a new path for the treatment of heart diseases 这一研究成果将为心脏病的医治开拓新的途径。
3.C[解析]第四段说，一个人20岁时，其每年被更替的心肌细胞为1%，随着年龄的增长，该更替率( turnover rate)不断下降，等到75岁时，只有0.45%。
4.A [解析]倒数第三段说：Chronic heart failure arises from heart cells dying。慢性心衰是由心肌细胞死亡导致的。
5.C[解析]最后一句说：心脏产生的新细胞的数量是按照健康心脏计算的，而有心脏病的细胞更替率是否与健康心脏相同还不得而知。
http://jianlimoban.c321.cn/【职称英语卫生类B试题解析3】相关文章：
2013职称英语卫生类B试题解析（2）07-15
2013职称英语卫生类B试题解析（4）07-15
2013职称英语卫生类B试题解析507-15
2013职称英语卫生类B试题解析（6）07-15
职称英语考试2006年全真模拟试题卫生类B级(二)07-29
职称英语考试卫生类阅读试题07-28