首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
考研
There’s a human liver sitting in a lab dish in Madison, Wis. Also a heart, a brain and every bone in the human body even though
There’s a human liver sitting in a lab dish in Madison, Wis. Also a heart, a brain and every bone in the human body even though
admin
2011-02-25
70
问题
There’s a human liver sitting in a lab dish in Madison, Wis. Also a heart, a brain and every bone in the human body even though the contents of the dish are a few cells too small to be seen without a microscope. But these are stem cells, the most immature human cells ever discovered, taken from embryos before they had decided upon their career path in the body. (46)
If scientists could only figure out how to give them just the right kick in just the right direction, each could become a liver, a heart, a brain or a bone.
(47)
When a team from the University of Wisconsin announced their discovery, doctors around the world looked forward to a new era of medicine one without organ-donor shortages or the tissues-rejection problems that bedevil transplant patients today.
Doctors also saw obstacles, though. One of them was a U. S. Congress skittish about research on stem cells taken from unwanted human embryos and aborted fetuses. Indeed, 70 lawmakers asked in a firmly worded letter that the Federal Government ban all such work.
Yet the era of "grow your own" organs is already upon us, as researchers have sidestepped the stem cell controversy by making clever use of ordinary cells. Today a machinist in Massachusetts is using his own cells to grow a new thumb after he lost part of his chest wall in an accident. A teenager born without half of his chest wall is growing a new cage of bone and cartilage within his chest cavity. Scientists announced that bladders, grown from bladder cells in a lab, have been implanted in dogs and are working. Meanwhile, patches of skin, the first "tissue-engineered" organ to be approved by the U. S. Food and Drug Administration, are healing sores and skin ulcers on hundreds of patients across the U. S.
How have scientists managed to do all this without those protean stem cells? Part of the answer is smart engineering. (48)
Using materials such as polymers with pores no wider than a toothbrush bristle, researchers have learned to sculpt scaffolds in shapes into which cells can settle.
The other part of the answer is just plain cell biology. (49)
Scientists have discovered that they don’t have to teach old cells new tricks; given the right framework and the right nutrients, cells will organize themselves into real tissues as the scaffolds dissolve.
"I’m a great believer in the cells. They’re not just lying there, looking stupidly at each other," says Francois Auger, an infectious disease specialist and builder of artificial blood vessels at Laval University in Quebec City. "They will do the work for you if you treat them right."
Replacement hearts—or even replacement heart parts—are at least a decade off, estimates Kiki Hellman, who monitors tissue-engineering efforts for the FDA. "Any problem that requires lots of cell types ’talking’ to one another is really hard," she notes. Bone and cartilage efforts are much closer to fruition, and could be ready for human trials within two years. (50)
And what of those magical stem cells that can grow into any organ you happen to need—if the law and biologists’ knowledge permit?
"Using them," says Sefton, "is really the Holy Grail."
选项
答案
研究人员利用诸如上端有牙刷毛大小细孔的聚合物之类的物质,搭构成细胞可以着床安歇的形状。
解析
句子的框架是Using materials…,researchers have learned to sculpt scaffolds in shapes into which cells can settle。现在分词作方式状语,shapes后跟定语从句。no wider than译为“如……一样窄”。
转载请注明原文地址:https://kaotiyun.com/show/vzp4777K
0
考研英语一
相关试题推荐
Inthefollowingtext,somesentenceshavebeenremoved.ForQuestions41-45,choosethemostsuitableonefromthelist(A、B、C、
Thepersonwhocanseeashipwithoutsomefeelingofexcitementmusthaveverylittleimagination.Eventheideaofleavingthe
Theauthor’sattitudetowardsthecurrentsituationintheexploitationofnaturalresourcesis______Accordingtotheauthor,
Thefirstmassiveelectroniccomputerswere______Wemaybelievethatsuchwordsasthoughtandthinking______
Whichofthefollowingbeststatesthemainpointofthepassage?______Itcanbeinferredfromthepassagethatonewayinwhi
YourforeignfriendClarehasjustgraduatedfromBeifangUniversityinChinaandplanstogobacktotheUnitedStatessoon.Wr
SometimebetweendigestingChristmasdinnerandputtingyourheadbackdowntowork,spareathoughtortwoforthecranberry.
China’sentryintotheWTOactuallyrepresentstheresultofathree-sidedwin-winsituation-China,theUnitedStatesandthe
China’sentryintotheWTOactuallyrepresentstheresultofathree-sidedwin-winsituation-China,theUnitedStatesandthe
ItisimpossibletomeasuretheimportanceofEdisonbyaddingupthespecificinventionswithwhichhisnameisassociated.Far
随机试题
简述幼儿园美育的意义。
下列哪种凝血因子不属于蛋白质()。
穿髓孔内由表及里依次为炎性、坏死渗出,炎性肉芽组织及新生的胶原纤维,有活性的散在炎细胞浸润的牙髓组织的变化见于
心脏压塞不会出现
甲、乙、丙、丁共同投资设立合伙企业,约定利润分配比例为4:3:2:1,现甲、乙退伙,丙、丁未就现有合伙企业利润约定新的比例。依照法律规定,现该合伙企业利润在丙丁之间如何分配?
关于刑法解释的说法,下列哪一选项是正确的?()(2009年卷二第1题)
某装饰装修工程的下列单项合同额中属于中型工程的是()万元。
专用会计核算软件也称为()。
某班的班干部在看到班上的同学违反纪律时,会将情况报告给老师。这体现出的高级情感是()。
给定资料l~3反映:湖北襄樊5名贫困大学生,因为在受助的一年多时间内没有任何“感恩”表示,被取消继续受资助资格。此事一经报道,评论纷至沓来,形成了两种对立的观点:一是认为这些贫困大学生懂得知恩图报是最基本的道德要求,应该感恩;二是认为资助者资助的目的不应是
最新回复
(
0
)