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[SANET-MG] part huam chimeras coming
Mouse human chimeras have been produced for several years using nude 
mice who lack immune systems and human cancers transplants  or human 
testicles which are born on the backs of the mice, rather like school 
back packs. Human chimeras are spreading to other animals.
Now scientists create a sheep that's 15% human
CLAUDIA JOSEPH
UK Daily Mail
Sunday, March 25, 2007
Scientists have created the world's first human-sheep chimera - which 
has the body of a sheep and half-human organs.
The sheep have 15 per cent human cells and 85 per cent animal cells - 
and their evolution brings the prospect of animal organs being 
transplanted into humans one step closer.
Professor Esmail Zanjani, of the University of Nevada, has spent seven 
years and £5million perfecting the technique, which involves injecting 
adult human cells into a sheep's foetus.
He has already created a sheep liver which has a large proportion of 
human cells and eventually hopes to precisely match a sheep to a 
transplant patient, using their own stem cells to create their own flock 
of sheep.
The process would involve extracting stem cells from the donor's bone 
marrow and injecting them into the peritoneum of a sheep's foetus. When 
the lamb is born, two months later, it would have a liver, heart, lungs 
and brain that are partly human and available for transplant.
"We would take a couple of ounces of bone marrow cells from the 
patient,' said Prof Zanjani, whose work is highlighted in a Channel 4 
programme tomorrow.
"We would isolate the stem cells from them, inject them into the 
peritoneum of these animals and then these cells would get distributed 
throughout the metabolic system into the circulatory system of all the 
organs in the body. The two ounces of stem cell or bone marrow cell we 
get would provide enough stem cells to do about ten foetuses. So you 
don't just have one organ for transplant purposes, you have many 
available in case the first one fails."
At present 7,168 patients are waiting for an organ transplant in Britain 
alone, and two thirds of them are expected to die before an organ 
becomes available.
Scientists at King's College, London, and the North East Stem Cell 
Institute in Newcastle have now applied to the HFEA, the Government's 
fertility watchdog, for permission to start work on the chimeras.
But the development is likely to revive criticisms about scientists 
playing God, with the possibility of silent viruses, which are harmless 
in animals, being introduced into the human race.
Dr Patrick Dixon, an international lecturer on biological trends, 
warned: "Many silent viruses could create a biological nightmare in 
humans. Mutant animal viruses are a real threat, as we have seen with HIV."
Animal rights activists fear that if the cells get mixed together, they 
could end up with cellular fusion, creating a hybrid which would have 
the features and characteristics of both man and sheep. But Prof Zanjani 
said: "Transplanting the cells into foetal sheep at this early stage 
does not result in fusion at all."
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