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BeBro
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of the Krauts
Mar 2000
time: 06:33
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http://www.cnn.com/2004/HEALTH/02/1...lone/index.html
quote:
WASHINGTON -- Researchers from South Korea say they have cloned human embryos and extracted from them stem cells in a development that experts hope could spark a medical revolution.
The experiment, which is reported in Friday's edition of the respected American magazine Science, is viewed as a major advance towards growing patients' own replacement tissue to treat diseases.
Previous attempts to clone a human embryo to produce stem cells are believed to have failed -- despite claims to the contrary -- and the report is likely to revive controversy around the world over the technique.
Critics have attacked such experiments as unethical because of the destruction of the embryos, however tiny. The U.S. government is trying to outlaw all cloning both in America and around the world.
In the experiment, scientists from Seoul National University said they collected 242 human eggs and succeeded in creating the 30 blastocrysts -- early-stage embryos containing about 100 cells.
From these they harvested one colony of stem cells that have the potential to grow into any tissue -- without being rejected by a patient's immune system.
The technique raises the hope of revolutionary treatments for diabetes, Parkinson's and other diseases, but any therapy is years away from being tested in people.
"Our approach opens the door for the use of these specially developed cells in transplantation medicine," Dr. Woo Suk Hwang, who led the study, said in a statement.
Experts on cloning praised the work.
"It is a very impressive study. It obviously represents a major medical milestone," Dr. Robert Lanza, from Advanced Cell Technology, told Reuters on Thursday.
"I think it could help spur a medical revolution."
And stem-cell researcher Dr. Rudolf Jaenisch of the Whitehead Institute for Biomedical Research in Cambridge, Massachusetts told The Associated Press the experiment proved the technique was possible using human cells.
"That's an important point to prove," he said.
Still, "it's not of practical use at this point," Jaenisch said, stressing that years of additional research were required.
The reports will renew debate over whether human cloning should be banned. The U.S. House last year voted to do that, but the Senate stalled over whether there should be an exception for research of this type.
Internationally, the U.S. is pushing for a United Nations ban of all human cloning, too. The U.N. General Assembly recently postponed a decision.
There is almost universal support for a global ban of reproductive cloning, but Britain and several other countries want cloning for medical experiments to be permitted.
Jaenisch said he regretted that most U.S. scientists could not experiment with the Seoul researchers' new stem-cell line.
Extracting stem cells from embryos kills them and U.S. President George W. Bush has banned any federally funded research on stem cells from embryos destroyed after August 9, 2001 -- making the South Koreans' recently developed line too new.
Further experiments in Seoul suggest the stem-cell colony could produce different types of body cells, AP reported. It began to form muscle, bone and other tissues in test tubes and when implanted into mice.
The team said it was now studying how to direct which tissues those cells form.
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Barinthus
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A Magical Moment...
Jan 2004
time: 21:33
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quote:
Originally posted by curtsibling
On what level do you have a problem with cloning a copy of a living human for organ harvesting? |
In that case, those human beings would be... human beings which are entitled to basic human rights. They're not animals nor farms to be harvested.
I prefer to clone organs themselves using stem cells instead of growing actual human beings.
EDIT: Let me expand on this some more. I've read about the possiblity of having stem cell banks in which some stem cells are taken from an emybro during a pregnancy. Those cells would be stored and then suppose 25 years later, the person got in an accident and the liver get destroyed or something, doctors can come back to that person's stem cells and use those cells to grow a new liver. The advantage is that since the new liver's from the same stem cells that the body grew from, the body would not reject the liver.
I'd like to take an opportunity to bring up a thought. Hopefully someone with extensive knowledge of biochemistry can help me out here ( I know at least one of you are studying that field!). From what I understand, basically, when one die of old age, it means on the cellular level, cells has been replicating itself so often that the quality of new copies are not as good and eventually the quality is so poor those cells just don't function. (cell A replicates itself into cell A.1 which replicates itself into cell A.2 copying from A.1 not A and so on. Imagine doing that with a paper and a copier. 100th copy wouldn't be as good as the first copy) When the body has so many of cells that are not functioning, the body die. Would it be possible to use stem cells to revitalize the body? Those cells would be closer to orginial copies. Would this enable a person to live longer until basically his brains stop functioning?
Last edited by Barinthus on 12-02-2004 at 21:30
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Eli
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Israel
Jul 2000
time: 07:33
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quote:
From what I understand, basically, when one die of old age, it means on the cellular level, cells has been replicating itself so often that the quality of new copies are not as good and eventually the quality is so poor those cells just don't function. (cell A replicates itself into cell A.1 which replicates itself into cell A.2 copying from A.1 not A and so on. Imagine doing that with a paper and a copier. 100th copy wouldn't be as good as the first copy |
That's what happens when you use analog systems...
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Starchild
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a raving alcoholic drama queen with a penchant for the biosciences
Jan 1970
time: 00:33
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quote:
Originally posted by DataAeolus
I'd like to take an opportunity to bring up a thought. Hopefully someone with extensive knowledge of biochemistry can help me out here ( I know at least one of you are studying that field!). From what I understand, basically, when one die of old age, it means on the cellular level, cells has been replicating itself so often that the quality of new copies are not as good and eventually the quality is so poor those cells just don't function. (cell A replicates itself into cell A.1 which replicates itself into cell A.2 copying from A.1 not A and so on. Imagine doing that with a paper and a copier. 100th copy wouldn't be as good as the first copy) When the body has so many of cells that are not functioning, the body die. Would it be possible to use stem cells to revitalize the body? Those cells would be closer to orginial copies. Would this enable a person to live longer until basically his brains stop functioning? |
The ends of chromosomes have "caps" called telomeres. As the cell divides, genetic information gets copied and these telomeres are eroded. That's because, IIRC, the copying enzymes can't actually grab onto the end of the DNA coil but have to start a bit of the way into it. Telomeres are genetic safeguards, meaningless bits of DNA that can get worn away safely instead of having functioning genes be degraded.
So as a person ages, their telemores wear down, increasing the chance of genetic damage when the cell next divides. Cancer cells (and I think stem cells but don't quote me on that) possess an enzyme called telomase that can rebuild telomeres. That's why cancer cells are so very long lived. However, once the cells are assigned their "proper" role in life, such as liver or nerve cell, they can no longer manufacture telomase.
So there's really not much point in growing a human clone to adulthood to harvest its organs. The organs would be the same age as the person since the original genetic material would have to come from the adult needing the organs. Growing organs from preserved stem cells makes more sense since the organ is geneticall "younger" than one from a clone.
Also, stem cells aren't closer to the original copy. Cloned stem cells are the original copy. Of course, there's a lot more to aging and death than telomore erosion. Free radicals (like che) play a part too along with tons more stuff.
In the end, flesh with always turn to dust. That's why my money is on uploading human minds into machine bodies.
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12-02-2004 16:23
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