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I like the idea of chimeras and I like mice. Wish my dog could talk. Ray ----- Original Message ----- From: "M.Schild" <[log in to unmask]> To: <[log in to unmask]> Sent: Monday, October 17, 2005 11:31 PM Subject: human cells in mouse brain > By Dianna Bai > Monday, October 17, 2005 > last updated October 17, 2005 12:27 AM > > Can the cure to Alzheimer's, Parkinson's and a long list of other fatal > genetic diseases be found in the mind of a mouse? It just might be > possible > with recent, but controversial, developments in stem cell research. > > Irving Weissman, director of Stanford's Institute for Stem Cell Biology > and > Regenerative Medicine, has worked with the transfer of human neurons to > the > brains of mice for several years now. He has already bred mice whose > brains > are composed of 1 percent human neurons, finding that transplanted human > brain cells could successfully connect to a mouse brain. > > > "Remarkably, even though humans and mice are separated by millions of > years > of evolution, human neurons responded to the mouse signals," Weissman > said. > > > Now, he wants to initiate a new experiment by transplanting human > brain-stem > cells to an inbred strain of mice whose natural brain cells die before the > mice's birth. Human brain cells would then replace the mice's own, > creating a > breed of mice whose brains are composed entirely of human neurons. > > > Although Weissman acknowledged that the experiment "may not even work at > all" > - if it were to be successful, scientists would have a way to study living > human-brain cells in a lab animal. Researchers, according to Weissman, > would > then be able to experiment on diseased human neurons in lab animals in > ways > that they could not with human subjects due to the high risks. > > > But even with the potential benefits, blurring the line between species > has > always brought up many ethical concerns in the scientific community, as > well > as negative reactions from the public. > > > As part of an ethics committee gathered together by Weissman, Stanford Law > Prof. Henry Greely has identified four ethical questions concerning the > project. They include the use of stem cells from aborted fetuses, the > inappropriate use of human tissue and the pain and suffering of the > laboratory mice. > > > However, the main concern, Greely said, is "running the risk of conferring > aspects of humanness in the mice." > > > In other words, the creation of a human chimera - a mouse with human > consciousness. > > > In Greek mythology, chimeras were hybrid creatures with bodies of goats, > heads > of lions and tails of snakes. But both Weissman and Greely agreed that the > project in question is nowhere near so sensational. > > > This past July, Sen. Sam Brownback (R-Kan.) introduced a bill to prohibit > the > creation of human chimeras. If passed, the new legislation would ban > experiments like Weissman's, even making them subject to criminal penalty. > > > "If passed, the legislation might make it a 10-year prison sentence to > conduct experiments like these," Greely said. > > > He also mentioned that the strongest reaction from the public to human > chimeras is usually the "yuck factor." > > > "People have talked about giving this mouse a human brain, but that would > not > be true," Greely said. "It would be unlikely to truly impossible for these > mice to exhibit human ability." > > > He stressed that neurons only comprise about 10 percent of the brain, > while > the connections between neurons are what scientist believe determine > consciousness. Greely described neurons as the bricks that make up the > brain. > > > "A church built with red bricks instead of gray will still be a church > because > the framework has not changed, just as the structure of the mouse's brain > has > not changed," he said. "What's important is the architecture, not the > bricks." > > > Stanford students surveyed also doubted the possibility of someone > creating a > "Stuart Little." > > > "I'd be interested to see the results of the experiment, but I don't think > the mouse is going to get up and start talking," said freshman Jonathan > Scrafford. "But if it did, then it would raise some issues." > > > Others said they did not believe the experiment raised any serious ethical > questions. > > > "It doesn't bother me that much," said junior Daniel Jacobs. "Even if the > worst thing happened and all the human behavior was transferred to a > mouse, > it wouldn't be that bad." > > > Junior Andrew Liefer, the technology columnist for The Daily, said he had > mixed feelings about the experiment. > > > "All this research is good because it's helping solve a lot of problems, > but > it'd be nice if people thought about the ethical concerns a little more," > he > said. > > > Greely's recommendation to Weissman was to forge ahead step-by-step and to > look for humanness in the structure of the mouse brain before proceeding > further. > > > "If everything looks mouse-like, go forward. If anything looks > un-mouselike, > stop," he said. > > > But at the moment, Weissman's proposed mouse project still has not begun > as > he waits for the scientific community's approval after reviewing the > ethical > concerns raised by the experiment. > > > "This project will test human neuronal cells in a mouse brain > micro-environment as a prelude to studying stem cells that have human > genetic > diseases like Alzheimer's, Parkinson's, Lou Gehrig's, and cerebral palsy," > Weissman said. > > > Weissman emphasized the urgency of his project as he asked, "Which of > these > diseases should we not be working on as fast as we can?" > > ---------------------------------------------------------------------- > To sign-off Parkinsn send a message to: > mailto:[log in to unmask] > In the body of the message put: signoff parkinsn > ---------------------------------------------------------------------- To sign-off Parkinsn send a message to: mailto:[log in to unmask] In the body of the message put: signoff parkinsn