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embryonic stem cell胚胎干细胞

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发布时间：2020-07-20

更多“embryonic stem cell胚胎干细胞”相关的问题

第1题

The US debate on human cloning gathered steam recently, moving toward federal legislation

that could affect both next fall's Congressional elections and the pre-eminence of US scientists in the worldwide race to turn research on human embryonic stem cells into a therapeutic revolution.

Testimony at a US Senate hearing on 5 March debated a bill proffered by Republican Senator Sam Brownback (Kansas) that would impose criminal penalties on all attempts at transferring a human somatic cell nucleus into a human egg, whether the purpose was to create an infant (usually called reproductive cloning) or to derive embryonic stem cells for disease research (usually called therapeutic cloning.) The US House of Representatives passed a similar total ban last year. Two other bills have also been introduced into the Senate; both would ban reproductive human cloning but permit therapeutic cloning.

Meanwhile, President Bush is expected to fill the long-vacant top job at the National Institutes of Health this week with Elias Zerhouni, executive vice dean of the Johns Hopkins University School of Medicine in Balthnore. For several months the front-runner for NIH director had been AIDS expert Anthony Fauci, head of the National Institute of Immunological Diseases and Stroke. The campaign against Fanci was led by Brownback, who regarded him as insufficiently pro-life. Zerhouni is said to have endorsed Brownbacks anti-cloning bill in writing.

The Bush administration also proposed last week that the United Nations adopt a Brownback type worldwide ban on human cloning, including therapeutic cloning. The UN is considering prohibiting reproductive cloning, but delegates from Europe and Asia oppose interfering with cloning to produce embryonic stem cells for research.

The US Senate hearing starred Christopher Reeve, Hollywood's former Superman, a persuasive high-profile advocate for stem cell research who is handsome as ever, but paralyzed from the shoulders down and unable to breathe on his own because of a riding accident some years ago. Testifying against the Brownback bill, Reeve told the hearing that only human embryonic stem cells carrying his own DNA offered hope for remyelinating his devastated spinal nerves via an immunologically compatible cell transplant. Also testifying against the bill was the hearing's scientific star, Nobel laureate Paul Berg of Stanford University. Berg argued that human stem cells not only could solve the problem of transplant rejections, they also could provide a unique source of information about common chronic late-onset diseases such as cancer. Studying cells from young people carrying mutations that predispose them to complex disorders could illuminate the disease process and generate clues to prevention or cure, he said. As both these applications are based on transfer of particular nuclei into human eggs, he pointed out, none of the existing 78 human embryonic stem cell lines President Bush approved for federally funded research last summer would be useful either for complex disease research or for compatible transplants.

Berg also objected strongly to both the Brownback and the House bills' ban on importing therapies based on human embryonic stem cell research done elsewhere in the world. That would prevent 280 million Americans from taking advantage of treatments developed in nations such as the UK where some of this research is permitted, he pointed out. It might even mean that Americans who seek such treatments abroad could be arrested and fined when they return, he predicted.

Both Reeve and Berg have suggested that a comprehensive ban on human cloning would put US scientists at a competitive disadvantage. The US would take a giant step backward in research leadership, Reeve noted, and anyway the work would be done abroad, for example in Europe. "Those are not rogue nations behaving irresponsibly," he told the Senate. Berg has said that h

A．Both reproductive and therapeutic cloning

B．Reproductive cloning only

C．Therapeutic cloning only

D．Neither reproductive nor therapeutic cloning

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第2题

A Cloud of Stem CellThe pressure on stem cell pioneer Woo Suk Hwang over the way he obtain

A Cloud of Stem Cell

The pressure on stem cell pioneer Woo Suk Hwang over the way he obtained human eggs for his research is intensifying-particularly in South Korea, where he had been a national hero. In the past week, several new claims have emerged that Hwang may have used eggs that were paid for, as well as eggs from junior members of his laboratory.

Hwang's team, based at South National University, has produced a string of landmark papers in stem cell research, including the first stem cells obtained from a cloned human embryo(胚胎)(W. S. Hwang et al. Science 303, 1669-1674; 2004) and the first patient-matched embryonic stem cells(W. S. Hwang et al. Science 308, 1777-1783; 2005).

For South Korean scientist, cloning pioneer and Snuppy creator, Woo Suk Hwang, things keep going from bad to worse. Last month, he had to admit that as part of the groundbreaking stem cell research he published in 2004, one of his colleagues had paid some women for their egg donations, and that two of the unpaid donors were Hwang's own junior researchers. Amid the moral controversy that followed, Hwang was in hospital for extreme fatigue and exhaustion. He was released earlier this week, only to find one of his former researchers on a national news broadcast claiming that the history-making stem cell lines Hwang created were fake.

The news broadcast was part of a multi-part investigative series by Korea's MBC-TV. Also in the broadcast, the researcher said that Hwang had told him to make up data in order to make it appear as if the South Koreans had created more stem cells, made from patients with diseases, than they actually had. "This is something I shouldn't have done," said the researcher, whose face was not shown on camera and was only identified by his last name, Kim. "I had no choice but to do it."

In a separate interview, Roh Sung Li, the doctor who had provided donated eggs to Hwang's research, said that Hwang had asked Science, the journal that published his paper on patient-specific stem cells, to withdraw the publication. A spokesperson at the journal said that they had not yet received a request to take back, but have e-mailed all 25 co-authors asking for clarification of the allegations(指控). Roh told news media that of the 11 stem cell lines created from patients with diseases, nine were fake. Whether the two remaining lines were valid, and photographed repeatedly to stand in for the other lines, is not clear. Roh also claims that after a visit to Hwang on Thursday, he believes there were no stem cells at all, and that all of the colonies had died in the lab. "I heard some things that I haven't been aware of when I visited Professor Hwang at his request, that there are no embryonic stem cells," he told MBC.

These latest claim comes just 24 hours after a former Hwang cooperator, Dr. Gerald Schatten of the University of Pittsburgh, charged Hwang with fabricating his data. Back in June, the two men had co-authored a paper published in Science that detailed how individual stem cell lines were created for 11 patients through cloning. When Hwang's immoral deeds were uncovered last month, Schatten was already publicly distancing himself from his onetime colleague. But on Tuesday, Schatten, took the next step and asked that his name be removed from the work. His reasons？ "Careful re-evaluations of published figures and tables," he said in his letter, "along with new problematic information, now cast substantial doubts about the paper's accuracy." Hwang has still not responded to these new accusations(指控), and Schatten has declined to comment further.

Hwang's academic affair is the latest plot twist in a drama that's playing out in the Korean press. Several days after Schatten's initial break with Hwang, Seoul's news outlets cited a Korean government official and other sources in both Korea and the U.S., claiming that Schatten had met with

A．Y

B．N

C．NG

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第3题

Well, he made it up. All of it, apparently. According to a report published on December 29

th by Seoul National University in South Korea, its erstwhile employee Hwang Woo-suk, who had tendered his resignation six days earlier, deliberately falsified his data in the paper on human embryonic stem cells that he and 24 colleagues published in Science in May 2005.

In particular, Dr Hwang claimed he had created 11 colonies of human embryonic stem ceils genetically matched to specific patients. He had already admitted that nine of these were bogus, but had said that this was the result of an honest mistake, and that the other two were still the real McCoy. A panel of experts appointed by the university to investigate the matter, however, disagreed. They found that DNA fingerprint traces conducted on the stem-cell lines reported in the paper had been manipulated to make it seem as if all 11 lines were tailored to specific patients. In fact, none of them matched the volunteers with spinal-cord injuries and diabetes who had donated skin cells for the work. To obtain his promising "results", Dr Hwang had sent for testing two samples from each donor, rather than a sample from the donor and a sample of the cells into which the donor's DNA had supposedly been transplanted.

The panel also found that a second claim in the paper — that only 185 eggs were used to create the 11 stem cell lines — was false. The investigators said the actual number of eggs used was far larger, in the thousands, although they were unable to determine an exact figure. The reason this double fraud is such a blow is that human embryonic stem-cell research has great expectations. Stem cells, which have not yet been programmed to specialise and can thus, in principle, grow into any tissue or organ, could be used to treat illnesses ranging from diabetes to Parkinson's disease. They might even be able to fix spinal-cord injuries. And stem cells cloned from a patient would not be rejected as foreign by his immune system.

Dr Hwang's reputation, of course, is in tatters. The university is now investigating two other groundbreaking experiments he claims to have conducted — the creation of the world's first cloned human embryo and the extraction of stem cells from it, and the creation of the world's first cloned dog. He is also in trouble for breaching ethical guidelines by using eggs donated by members of his research team.

And it is even possible that the whole farce may have been for nothing. Cloned embryos might be the ideal source of stem cells intended to treat disease, but if it proves too difficult to create them, a rough-and-ready alternative may suffice.

From the passage we may learn that Hwang Woo-suk ______.

A．made up all his experience

B．is a famous geneticists in Seoul National University

C．was an employee in Seoul National University

D．published an authentic paper in Science with his 24 colleagues

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第4题

胚胎干细胞（embryonic stem cells，ES cells)

胚胎干细胞(embryonic stem cells，ES cells)

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第5题

On which of the following aspects does Frisen disagree with some radicals？A．Whether resear