X-Message-Number: 26111
From: "Basie" <>
Subject: Sheep with human brain
Date: Fri, 29 Apr 2005 19:09:43 -0400

This is what Cryo scientists need!

Basie

Genetic Mingling Mixes Human, Animal Cells By PAUL ELIAS, AP Biotechnology 
Writer
Fri Apr 29, 3:58 PM ET

RENO, Nev. - On a farm about six miles outside this gambling town, Jason 
Chamberlain looks over a flock of about 50 smelly sheep, many of them 
possessing partially human livers, hearts, brains and other organs.
The University of Nevada-Reno researcher talks matter-of-factly about his 
plans to euthanize one of the pregnant sheep in a nearby lab. He can't wait 
to examine the effects of the human cells he had injected into the fetus' 
brain about two months ago.

"It's mice on a large scale," Chamberlain says with a shrug.

As strange as his work may sound, it falls firmly within the new ethics 
guidelines the influential National Academies issued this past week for stem 
cell research.

In fact, the Academies' report endorses research that co-mingles human and 
animal tissue as vital to ensuring that experimental drugs and new tissue 
replacement therapies are safe for people.

Doctors have transplanted pig valves into human hearts for years, and 
scientists have injected human cells into lab animals for even longer.

But the biological co-mingling of animal and human is now evolving into even 
more exotic and unsettling mixes of species, evoking the Greek myth of the 
monstrous chimera, which was part lion, part goat and part serpent.

In the past two years, scientists have created pigs with human blood, fused 
rabbit eggs with human DNA and injected human stem cells to make paralyzed 
mice walk.

Particularly worrisome to some scientists are the nightmare scenarios that 
could arise from the mixing of brain cells: What if a human mind somehow got 
trapped inside a sheep's head?

The "idea that human neuronal cells might participate in 'higher order' 
brain functions in a nonhuman animal, however unlikely that may be, raises 
concerns that need to be considered," the academies report warned.

In January, an informal ethics committee at Stanford University endorsed a 
proposal to create mice with brains nearly completely made of human brain 
cells. Stem cell scientist Irving Weissman said his experiment could provide 
unparalleled insight into how the human brain develops and how degenerative 
brain diseases like Parkinson's progress.

Stanford law professor Hank Greely, who chaired the ethics committee, said 
the board was satisfied that the size and shape of the mouse brain would 
prevent the human cells from creating any traits of humanity. Just in case, 
Greely said, the committee recommended closely monitoring the mice's 
behavior and immediately killing any that display human-like behavior.

The Academies' report recommends that each institution involved in stem cell 
research create a formal, standing committee to specifically oversee the 
work, including experiments that mix human and animal cells.

Weissman, who has already created mice with 1 percent human brain cells, 
said he has no immediate plans to make mostly human mouse brains, but wanted 
to get ethical clearance in any case. A formal Stanford committee that 
oversees research at the university would also need to authorize the 
experiment.

Few human-animal hybrids are as advanced as the sheep created by another 
stem cell scientist, Esmail Zanjani, and his team at the University of 
Nevada-Reno. They want to one day turn sheep into living factories for human 
organs and tissues and along the way create cutting-edge lab animals to more 
effectively test experimental drugs.

Zanjani is most optimistic about the sheep that grow partially human livers 
after human stem cells are injected into them while they are still in the 
womb. Most of the adult sheep in his experiment contain about 10 percent 
human liver cells, though a few have as much as 40 percent, Zanjani said.

Because the human liver regenerates, the research raises the possibility of 
transplanting partial organs into people whose livers are failing.

Zanjani must first ensure no animal diseases would be passed on to patients. 
He also must find an efficient way to completely separate the human and 
sheep cells, a tough task because the human cells aren't clumped together 
but are rather spread throughout the sheep's liver.

Zanjani and other stem cell scientists defend their research and insist they 
aren't creating monsters - or anything remotely human.

"We haven't seen them act as anything but sheep," Zanjani said.

Zanjani's goals are many years from being realized.

He's also had trouble raising funds, and the     U.S. Department of 
Agriculture is investigating the university over allegations made by another 
researcher that the school mishandled its research sheep. Zanjani declined 
to comment on that matter, and university officials have stood by their 
practices.

Allegations about the proper treatment of lab animals may take on strange 
new meanings as scientists work their way up the evolutionary chart. First, 
human stem cells were injected into bacteria, then mice and now sheep. Such 
research blurs biological divisions between species that couldn't until now 
be breached.

Drawing ethical boundaries that no research appears to have crossed yet, the 
Academies recommend a prohibition on mixing human stem cells with embryos 
from monkeys and other primates. But even that policy recommendation isn't 
tough enough for some researchers.

"The boundary is going to push further into larger animals," New York 
Medical College professor Stuart Newman said. "That's just asking for 
trouble."

Newman and anti-biotechnology activist Jeremy Rifkin have been tracking this 
issue for the last decade and were behind a rather creative assault on both 
interspecies mixing and the government's policy of patenting individual 
human genes and other living matter.

Years ago, the two applied for a patent for what they called a "humanzee," a 
hypothetical - but very possible - creation that was half human and chimp.

The U.S. Patent and Trademark Office finally denied their application this 
year, ruling that the proposed invention was too human: Constitutional 
prohibitions against slavery prevents the patenting of people.

Newman and Rifkin were delighted, since they never intended to create the 
creature and instead wanted to use their application to protest what they 
see as science and commerce turning people into commodities.

And that's a point, Newman warns, that stem scientists are edging closer to 
every day: "Once you are on the slope, you tend to move down it."

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