- Viable embryos have been created from dead people by
fusing their cells with empty cow eggs, a controversial fertility scientist
claimed on Tuesday.
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- Panayiotis Zavos, of the Kentucky Center for Reproductive
Medicine, Lexington, US, say his team has shown that cells taken from humans
after death could be used for cloning. This latest work is purely experimental
and no embryos were implanted for cloning, said Zavos, announcing the results
at his own press conference in London, UK.
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- However, the claims were immediately met with both revulsion
and scepticism from the UK scientific community.
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- The work is "both scientifically questionable and
ethically unacceptable", says Richard Gardner of the UK Royal Society's
working group on stem cell research and cloning. "It is grossly misleading
to suggest that you can replicate a loved one by producing a cloned person
with the same genetic material."
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- "This man preys on the strong desires of the most
vulnerable people in society - giving them false hopes," says Robin
Lovell-Badge, head of developmental genetics at the UK's National Institute
for Medical Research. Other scientists argue that, even if cloning a person
were possible, the risk of major birth defects is huge.
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- Peer review
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- "We have yet to see any proper description of any
of the procedures that Dr Zavos claims to be able to use. He should publish
his research in a recognised journal to prove that he is not a charlatan,"
says Lovell-Badge.
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- The UK's regulatory body, the Human Embryology and Fertilisation
Authority, refused to comment on Zavos's latest work without it being peer-reviewed.
Zavos says he has published a paper on earlier work in Reproductive Bio
Medicine Online and that other papers are currently being reviewed.
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- In the latest work, Zavos claims to have taken live cells
from the tissues of three dead people, injected them into cow eggs stripped
of their nuclei and then fused them using electrical stimulation.
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- The successfully fused embryos begin to cleave after
48 hours, says Zavos, dividing into a small ball of cells. Two of the three
human cells produced "viable embryos" which could have been implanted
in an attempt to produce a pregnancy, he says. Several other groups have
already created cloned embryos by fusing human cells with empty animal
eggs, starting in 1996.
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- Car crash
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- Zavos used blood and other tissues from an 11-year-old
girl who was killed in a car crash. Her parents kept the tissues in their
home refrigerator until they were delivered in dry ice to Zavos' group
three days later.
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- Cells were also used from a dead 18-month-old boy, but
the embryos produced survived until the four-cell stage only, Zavos says,
and so were not viable.
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- The third case was that of a 33-year-old man. His tissues
were harvested in the mortuary immediately after death, so the team was
able to culture them "just like fresh cells". These cells produced
embryos which grew to the 64-cell stage - "definitely transferable
embryos which can yield a viable pregnancy", says Zavos.
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- But both Gardner and Simon Fishel, director of fertility
centre CARE in Nottingham, UK, say the results add little to research.
Fishel told New Scientist: "One can't conceive of any useful information
that could come out of this at research level, let alone clinically."
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- Gardner notes that merely culturing healthy cells would
demonstrate their viability. And he adds that bovine eggs are particularly
good for cloning techniques: "Interspecific combination may well work
because it's an egg recipient in which we know cloning works ñ it
won't inform you as to whether it works in humans."
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