2006年VOA标准英语-Fetal Stem Cells Created Without Destroying Emb

By David McAlary
Washington
23 August 2006

A U.S. biotechnology company has developed a way to create human embryonic² stem cells for disease research and treatment without destroying the fetus³ they come from. The researchers say their technique solves the ethical⁴ problems involving the traditional procedure in which a fetus is killed.

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embryo1 to be used in generating embryonic stem cells for scientific research" src="/upimg/allimg/070417/1235380.jpg" width="210" border="0" /> In this photo made available by Advanced Cell Technology, a single cell is removed from a human embryo to be used in generating embryonic stem cells for scientific research

A team at the firm Advanced Cell Technology in Massachusetts has generated new lines of human embryonic stem cells while leaving the embryos⁵ intact.

Stem cells are master cells in embryos that can become any kind of tissue as the fetus develops. Scientists say the cells hold out hope as cures for many diseases if they can be injected into patients and stimulate⁶ the growth of healthy replacement⁷ tissue.

The standard method of obtaining stem cells has been to extract a large number of cells from an embryo at its blastocyst stage, when it is about five days old and has divided into about 100 cells. This method destroys the fetus and is very controversial.

President Bush has banned U.S. government funding for any research using embryonic stem cells created after August 2001, a decision opposed by most stem cell researchers and which Congress tried, but failed to overturn recently.

The Advanced Cell Technology group says its method avoids ethical objections by extracting only a single cell from each embryo at an earlier stage of development, leaving the rest to develop.

"We have shown that we cannot only generate stem cells without destroying the embryo, but that that remaining embryo also has the potential to go on to create a healthy hatching blastocyst," he said.

This is project leader Robert Lanza, speaking to interviewers for the journal Nature, where the research appears.

"What we're actually doing is removing a single cell from an eight-cell stage embryo, and then we actually culture that cell in the petri dish, and are actually able, though various manipulations, to create stable embryonic stem cell lines," he added.

Lanza says stem cells obtained this way are identical to those obtained by the traditional method. He says the new approach should satisfy President Bush and others who have opposed stem cell research because it killed embryos to obtain tissue.

However, some stem cell scientists complain that Lanza's technique is not as efficient as the standard method.

It also does not satisfy pro-life groups such as the U.S. Conference of Catholic Bishops⁸. Spokesman Richard Doerflinger says the single cell it uses could develop into a twin if not cultured into stem cells. Furthermore, Doerflinger says the U.S. government's National Institutes of Health says some fetuses⁹ that have had a single cell removed for genetic¹⁰ diagnosis¹¹ do not survive, while others that come to term are sometimes born with subtle defects.

"We're seeing a number of ethical problems in this. The procedure they are talking about of picking off a single cell from an early embryo is not as benign¹² as they say," he explained.

Robert Lanza says the procedure is still too new to use immediately, but is worth studying. His company is offering stem cell lines it has developed free to scientists.

1 embryo   

n.胚胎，萌芽的事物

参考例句：

• They are engaging in an embryo research.他们正在进行一项胚胎研究。
• The project was barely in embryo.该计划只是个雏形。

2 embryonic   

adj.胚胎的

参考例句：

• It is still in an embryonic stage.它还处于萌芽阶段。
• The plan,as yet,only exists in embryonic form.这个计划迄今为止还只是在酝酿之中。

3 fetus   

n.胎，胎儿

参考例句：

• In the fetus,blood cells are formed in different sites at different ages.胎儿的血细胞在不同时期生成在不同的部位。
• No one knows why a fetus is not automatically rejected by the mother's immune system. 没有人知道为什么母亲的免疫系统不会自动排斥胎儿。

4 ethical   

adj.伦理的，道德的，合乎道德的

参考例句：

• It is necessary to get the youth to have a high ethical concept.必须使青年具有高度的道德观念。
• It was a debate which aroused fervent ethical arguments.那是一场引发强烈的伦理道德争论的辩论。

5 embryos   

n.晶胚；胚，胚胎( embryo的名词复数 )

参考例句：

• Somatic cells of angiosperms enter a regenerative phase and behave like embryos. 被子植物体细胞进入一个生殖阶段，而且其行为象胚。 来自辞典例句
• Evolution can explain why human embryos look like gilled fishes. 进化论能够解释为什么人类的胚胎看起来象除去了内脏的鱼一样。 来自辞典例句

6 stimulate   

vt.刺激，使兴奋；激励，使…振奋

参考例句：

• Your encouragement will stimulate me to further efforts.你的鼓励会激发我进一步努力。
• Success will stimulate the people for fresh efforts.成功能鼓舞人们去作新的努力。

7 replacement   

n.取代，替换，交换；替代品，代用品

参考例句：

• We are hard put to find a replacement for our assistant.我们很难找到一个人来代替我们的助手。
• They put all the students through the replacement examination.他们让所有的学生参加分班考试。

8 bishops   

（基督教某些教派管辖大教区的）主教( bishop的名词复数 )； （国际象棋的）象

参考例句：

• Each player has two bishops at the start of the game. 棋赛开始时，每名棋手有两只象。
• "Only sheriffs and bishops and rich people and kings, and such like. “他劫富济贫，抢的都是郡长、主教、国王之类的富人。

9 fetuses   

n.胎，胎儿( fetus的名词复数 )

参考例句：

• DNA was extracted from fetuses at mid-gestation, about 10 days past conception. DNA从受孕大约10天后的中期妊娠胚胎中提取。 来自互联网
• Brucellosis is a disease that causes fetuses to abort in cattle. 普鲁士菌病是一种可以导致牲畜胎儿夭折的疾病。 来自互联网

10 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

11 diagnosis   

n.诊断，诊断结果，调查分析，判断

参考例句：

• His symptoms gave no obvious pointer to a possible diagnosis.他的症状无法作出明确的诊断。
• The engineer made a complete diagnosis of the bridge's collapse.工程师对桥的倒塌做一次彻底的调查分析。

12 benign   

adj.善良的，慈祥的；良性的，无危险的

参考例句：

• The benign weather brought North America a bumper crop.温和的气候给北美带来大丰收。
• Martha is a benign old lady.玛莎是个仁慈的老妇人。