From: Brett Paatsch (paatschb@ocean.com.au)
Date: Fri Nov 08 2002 - 11:18:46 MST
Robert Bradbury wrote:
>
> Well, it looks like the crafty Republicans are up to their old
> tricks again. Since they can't get a ban on cloning through the
> Senate, they are trying to do it via the U.N.
As I understand it the US senate was roughly even and deadlocked behind two
competing bills (no cloning at all) vs (therapeutic cloning ok). Has the
recent elections changed this situation at all?
I would presume that as things were not going straight down party lines (I
heard that Nancy Reagan was actively lobbying the Republicans) that the
recent elections would not have effected things enough to break the
deadlock.
Last I hear California was looking to legislate for therapeutic cloning in
its own right.
>
> See:
> U.S., Pushing for Broader Ban, Blocks U.N. Anti-Cloning Move
>
http://www.nytimes.com/2002/11/08/international/08CLON.html?pagewanted=print
>
> Seems Germany and France are pushing for a ban on reproductive cloning
> (which is fine by me at this point) and the U.S. is pushing back seeking
> a total ban on cloning.
>
> I don't see the point (other than if its pure politics). If they can't
get
> a U.S. ban through the Senate now -- how can they expect to get the Senate
> to approve a U.N. Treaty on a total ban? Perhaps they think generally
> uninformed international opinion will sway some votes???
>
> Worth noting is the downsides of this which seem to be at least
> (a) No cloning of bodies for cryonically suspended heads;
> (b) No migration into space (i.e. we are imprisoned on Earth)
> because you couldn't enforce a ban on cloning activities in
> some remote part of the solar system; and (c) greater difficulty
> developing the methods to grow replacement organs from stem cells.
>
As you noted in an earlier post there is some interesting work being done in
inducing tolerance.
>From talking to the commercial co's here in Oz, it seems that in the absence
of therapeutic cloning they are hoping that the tolerance stuff pans out.
But in any case, therapeutic cloning for body tissue generation is not
regarded amongst the commercial co's here as a cost effective solution for
tissue replacement. Its thought that it will be too slow and expensive to
grow tissues for a particular person.
What SCNT or therapeutic cloning does allow however is some good discovery
science if you can take cloned cells from a person with Parkinson's and
other genetic diseases, get them to differentiate into the appropriate
tissue you can test pharmaceuticals more directly (and safely) on the
diseased tissue.
It would also to nice to know exactly what the cocktail of factors are in
human oocytes, hESC's, and adult stem cells such as adult hematopoietic stem
cells. I'm really not sure why this has not yet been done with techniques
like electrophoresis. Perhaps they simply lack the sensitivity required. I
think the count for maternal factors in mouse oocytes is up to about 30.
Given that these factors/proteins are only needed to do the bootstrapping
before the genomic dna comes online I would have thought they should not be
too many different types and that they could be well conserved within higher
mammals (perhaps giving rise to the possibility of alternate sources for the
its protein/factors besides human oocytes).
There is a company called Bresagen which had a patent technique for fusing
ES cells together into one large multinucleate ES cell (comparable amounts
of cytoplasm to an oocyte I think is the point), they then introduce an
nucleus from a somatic cell (similar to the Dolly procedure). At this point
this has been performed only in mice and they haven't managed to remove the
multiple nuclei from the original ES cells. Bresagen is hoping it can remove
these and get the technique to work with human ES cells.
If so, it would nicely step around the ethical problem (to a substantial
extent) as the fused ES cell construct has no trophoblast it cannot implant
and is not deemed an embryo. Also perhaps even more importantly it would
require no human oocytes. Still remains to be seen whether this ES cell
nuclear reprogramming technique can be refined for human use or not.
Even if the egg problem is bypassed it seems likely that tolerance induction
or something like it will be required to bring costs down for affordable and
practical tissue matching.
Regards,
Brett
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