2015年職稱英語衛生類B級閱讀復習

　　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 born 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 be 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, 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

　　人體心臟可產生新細胞

　　科學家解開了一個為時甚久的謎團，他們發現人類心臟在人的一生中不斷地產生新的心肌細胞，盡管新細胞產生的速度隨年齡增長而放緩。

　　此番發現發表于今年4月3日出版的《科學》雜志，這一發現可能為心臟疾病的治療比如心臟衰竭、心臟病發作開辟出一條新途徑，老師稱。

　　“我們發現心臟中的搏動細胞心肌細胞是可再生的”，首席研究員喬納斯?弗瑞森談到。他是一名在瑞典斯德哥爾摩的卡羅林斯卡學院從事干細胞研究的教授。“早前并不清楚人們是否局限于出生時所具有的心肌細胞還是說這些細胞可以被更新”，他說。

　　這些細胞的更新過程隨時間的推移而有所變化，弗瑞森補充道。一個人20歲時，其每年被更替的心肌細胞約為l%，隨著年齡的增長，該更替率不斷下降，等到75歲時，只有0.45%。

　　“如果我們能明白新的心肌細胞的產生是如何控制的，我們就有可能開發出醫藥品來促進這一過程的實現，可以刺激心肌細胞的再生，比如在心臟病發作以后”，弗瑞森說。

　　這樣的治療方案可以幫助恢復受損心臟。

　　“許多人遭受慢性心力衰竭的折磨”，同樣來自卡羅林斯卡學院的文章合著者拉坦?布哈德瓦基指出。“慢性心力衰竭是由心肌細胞的死亡導致的”，他說。

　　有了這一發現，科學家們正在“打開讓我們自愈的潛在療法的大門”，布哈德瓦基說。“或許人們可以發明一種能使心肌細胞產生新的更多細胞的藥劑以克服他們正面臨的問題。”

　　話雖如此，困難尤存。根據布哈德瓦基的說法，科學家們還不知道如何使心臟細胞更新的速度快于細胞死亡的速度，尤其是對于那些心力衰竭的老年患者而言。此外，心臟產生新細胞的數量是按照健康心臟計算的，而有病心臟的細胞更替率是否與健康心臟相同還不得而知。