I just wrote:

> In that regard, how do you feel about dandruff?
>
>  It's not quite yet in our technical capability to clone a new individual
> from shed skin, and there are deep technical reasons to reject the use of
> such cells, but we're getting closer to being able to accomplish such a
feat
> every year.
>
>  But in such a world, the question of importance becomes: what deep moral
> force makes an unused blastocyte any different than shed skin other than
> personal whims? The proper answer is the probability of success.

In response, one person privately sent me the following article, which is the
lead article in today's issue of Wired Magazine's on-line edition:

=======================================

Cells That Go Back in Time

http://www.wired.com/news/medtech/0,1286,67155,00.html?tw=wn_tophead_1

By Kristen Philipkoski

02:00 AM Apr. 08, 2005 PT

Lop off a newt's leg or tail, and it will grow a new one. The creature's
cells can regenerate thanks to built-in time machines that revert cells
to early versions of themselves in a process called dedifferentiation.

Researchers who study this mechanism hope one day to learn how to induce
the same "cell time travel" in humans. If the cells go back far enough,
they become stem cells, which researchers believe hold promise for
treating many diseases. Stem cells, which are often taken from embryos,
are unformed and have the ability to become many different types of
cells. If researchers succeed in inducing this cell time travel, they
will also eliminate the ethical issues surrounding embryonic stem-cell
research, because no embryos would be destroyed to obtain the cells.

The research is in its infancy, but a 2001 discovery jump-started the
field of study. Mark Keating, Christopher McGann and Shannon Odelberg
applied a protein extract derived from newts to mouse muscle cells. To
their surprise, the protein extract transformed those muscle cells into
stem cells in just 48 hours, which means the mouse cells would have the
ability to regenerate.

No one expected the experiment to work. Previously, scientists believed
that once mammalian cells became muscle, bone or any other type of
cells, that was their fate for life -- and if those cells were injured,
they didn't regenerate, but grew scar tissue.

But Keating's experiment introduced the possibility that, under the
right circumstances, humans -- who are 99 percent genetically similar to
mice -- might one day be able to regenerate their own cells. Those
regenerated cells could be used to treat disease.

"For those of us who want to understand what happens in
dedifferentiation, our ultimate goal is to be able to form a pool of
stem-cell-like cells that would be able to repopulate the organ or
tissue you're trying to repair," said Catherine Tsilfidis, a scientist
at the Ottawa Health Research Institute who has reproduced Keating's
findings, which she describes as "beautiful."

In newts and some other animals with the ability to regenerate, cells at
the site of an injury can revert to their embryonic stem-cell stage and
can become another type of cell in that creature's body. In other words,
a skin cell can dedifferentiate into a stem cell, then regenerate into a
muscle cell or another completely different type of cell.

Tsilfidis and her colleagues are now trying to pinpoint which genes are
responsible for kick-starting newt dedifferentiation. They published
findings in the March 23 issue of Developmental Dynamics identifying 59
DNA fragments that seem to play a role in newt forelimb regeneration,
and Tsilfidis believes many of those gene fragments have counterparts in
humans.

"Whether (those genes) can actually induce dedifferentiation is yet to
be determined," Tsilfidis said. While the genes were active during
maximum dedifferentiation activity, she said, so much is going on in
cells after a newt's forelimb is cut off that it's difficult to pick out
specific dedifferentiation genes.

While some cells are dedifferentiating, others have already begun
regenerating and differentiating, or becoming specialized cells. They're
performing activities like healing wounds or growing blood vessels, so
it's difficult to pin certain genes to specific activities.

Researchers are trying to learn similar lessons from other creatures
that have the ability to regenerate, including starfish, zebrafish,
earthworms and lobsters.

Adult human bodies do contain some stem cells, but they are rare.

"Maybe only one in a million cells in a particular region might have
that regenerative capacity you're interested in," said Robert Naviaux,
who studies cancer and stem-cell differentiation, and is co-director of
the Mitochondrial and Metabolic Disease Center at the University of
California at San Diego. "Stem cells are more concentrated in certain
locations like human umbilical cords, blood and bone marrow, and certain
areas of the brain around the ventricles."

People who believe it's unethical to destroy any embryos, even those
abandoned and destined for destruction at in vitro fertilization
clinics, have touted adult stem cells as an ethical choice. The field
has seen some success, but many researchers believe adult stem cells
have less "plasticity," or ability to become different types of cells.

Others have promoted various schemes for getting around the embryo
conundrum, but none has received a unanimous stamp of approval from
scientists and religious groups or others who oppose the destruction of
embryos.

But at least one religious leader believes the ability to use
dedifferentiation to create human stem cells would eliminate the
controversy.

"I believe that dedifferentiation -- the direct conversion of a somatic
cell into an embryonic stem cell -- is the holy grail for those seeking
morally acceptable alternatives to the destructive embryo research now
required to obtain (embryonic stem) cells," said Father Nicanor
Austriaco, a molecular biologist and Catholic priest in Washington, D.C.
"You would also be able to get immunocompatible (embryonic stem) cells
from every patient by simply dedifferentiating his or her cells. This
would be an amazing discovery."

========================================

However amazing this might be, it only solves a part of the problem, and
that's only a philosophical problem of our own making. Errors accumulated in the
adult cells due to replicative entropy (the same kind of error that condemns a
xerox copy of a xerox copy, infinitely repeated, ultimately to a mass of black
and white dots) will not be rectified by this procedure.

Wirt Atmar

* To join/leave the list, search archives, change list settings, *
* etc., please visit http://raven.utc.edu/archives/hp3000-l.html *