- ....."All human embryonic stem cell lines approved
for use in federally funded research are contaminated with A FOREIGN MOLECULE
FROM MICE that may make them risky for use in medical therapies....."
-
- "Researchers have suspected that exposing the stem
cells to animal products could have contaminated them with viruses, proteins
or other molecules that be dangerous to people. NOW THEY HAVE EVIDENCE
IT DID."
- _______
-
- From Alan -
-
- AGAIN, THIS IS MORE EVIDENCE OF THE DANGERS OF GENETIC
ENGINEERING AND THE "species-jumping" EXPERIMENTS IN VIROLOGY
THAT HAVE BEEN GOING ON FOR THE PAST 5 DECADES -- AND WHICH ARE AT THE
ROOT OF MAN-MADE AIDS AND "EMERGING VIRUSES" (and new lethal
"bird flu"?)
-
- WHO WILL STOP THE INSANITY???????
- ________
-
- Stem Cell Contamination Worries
-
- Embryonic stem cells, hailed as a potential treatment
for a range of diseases, are contaminated by an animal molecule, researchers
suggest.
-
- The molecule's presence would lead the human immune
system to attack the cells.
-
- The University of California team, writing in Nature
Medicine, says this means such cells could not be used.
-
- They say the only solution is to create new stem cell
lines without using animal-derived products.
-
- It would seem best to start over again
- Dr Ajit Varki, University of California
-
- Human embryonic stem cells are taken from embryos created,
but not used, in fertility treatments.
-
- These cells can potentially generate every body cell
type.
-
- Once they have been removed, they are usually cultured
with animal-derived 'serum replacements', which are sources of sialic acid
Neu5Gc, a molecule against which many humans have circulating antibodies.
-
- Neu5Gc is found on the surface of animal cells, but
not on human cells and is therefore attacked by the human immune system.
-
- It is the reason why the human body rejects organs transplanted
from animals.
-
- New lines
-
- The Neu5Gc molecule is taken up by stem cells when they
are grown in laboratory cultures that contain animal-derived materials,
including so-called "feeder layers" from mice and foetal calf
serum.
-
- The study, led by Dr Ajit Varki at the Departments of
Medicine and Cellular and Molecular Medicine at the University of California,
found embryonic stem cells were contaminated with substantial amounts of
Neu5Gc.
-
- Dr Varki said: "The human embryonic stem cells
remained contaminated by Neu5Gc even when grown in special culture conditions
with commercially available serum replacements, apparently because they
are derived from animal products.
-
- "It would seem best to start over again with newly
derived human embryonic stem cells that have never been exposed to any
animal products."
-
- However, he said regulations in the US which only allows
federal funding to be given to research on embryonic stem cell lines created
before 2001 would mean such an approach could not be pursued without a
change in the law.
-
- Dr Stephen Minger of King's College London, who created
the first embryonic stem (ES) cell line in the UK, told the Times newspaper:
"My perspective has always been that, when we are serious about getting
ES cell therapies into the clinic, we will have to derive new lines completely
free from animal conditioning."
-
- Patrick Cusworth, a spokesman for the pro-life charity
Life, said: "If anything, this latest report has demonstrated the
sheer unpredictability of embryonic stem cells, and the enormous potential
hazards if these were implanted into human patients."
-
- © BBC MMV
- http://news.bbc.co.uk/go/pr/fr/-/1/hi/health/4201565.stm
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