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 | | From: | Scented Nectar | | Subject: | Re: Prions in Previously Unsuspected Organs | | Date: | Sat, 22 Jan 2005 16:37:55 -0500 |
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http://www.scentednectar.com/veg/
A huge directory listing over 700 veg recipe sites.
Has a fun 'Jump to a Random Link' button.
wrote in message
news:1106424143.314732.99280@c13g2000cwb.googlegroups.com...
> http://www.rense.com/general62/prion.htm
Also, there's an article in New Scientist about the
same thing. Here it is:
http://www.newscientist.com/article.ns?id=dn6907
Inflammation lets prions invade "safe" tissue
19:00 20 January 2005
NewScientist.com news service
Emily Singer
Inflammation can cause the deformed proteins
that cause prion diseases, such as BSE, to
invade organs that normally resist infection.
If the new research in mice holds true for cattle,
it could mean that some organs previously
thought to be safe to eat are not - with significant
implications for BSE testing programmes.
Previous screening tests have shown the prions
that cause BSE are found only in specific organs,
such as the brain and intestines. "So the
assumption has been that other parts are safe to
eat," says Adriano Aguzzi, at the University
Hospital of Zurich, Switzerland, who led the new
research.
"People in countries with BSE still eat steak
because the authorities say if you stay away
from the brain and lymphoid tissue, you should
be safe," he told New Scientist. However, the
experiments to find out where BSE prions lurk
in cattle incubating the disease have been
done in otherwise healthy animals, he says:
"If you have a sick cow, these rules may no
longer apply."
The US and UK agencies responsible for BSE
testing say the findings do not warrant any
immediate changes to existing regulations,
but say they plan to review the new research in
depth.
Infectivity can vary between species, says
Danny Matthews, at the UK Department for
Environment, Food and Rural Affairs, so
the results need to be replicated in cattle.
The officials also claim that inflamed tissue
can be identified and removed from
carcasses along with specified risk organs.
Prion bioreactor
However, if the findings of Aguzzi's team
translate to cattle, changes may be needed.
Current European surveillance programs
test the central nervous system of
slaughtered cattle for signs of infection,
on the assumption that even animals
incubating the disease poses no risk to
consumers until prions show up in the brain.
But if inflamed organs are infected with
prions earlier than brain tissue - as
preliminary results from Aguzzi's lab
suggest - animals whose brains test
negative for BSE could still be carrying
dangerous levels of prions in other organs,
and those could end up in food.
In their new study, the researchers tested
mice with five different inflammatory
diseases of the kidney, pancreas and
liver. They found that in all cases, chronic
inflammation caused a build up of prion
proteins in organs that are normally
prion-free.
"The organ transforms itself into a bioreactor
for prions," says Aguzzi. For example,
diabetic mice injected with prions end up
with a pancreas full of the misfolded protein,
while the organ is unaffected in healthy mice.
Immune reaction
While inflammation does affect where prions
accumulate, it does not make animals more
susceptible to brain infection or affect how
quickly the disease makes the animals sick.
The team now plans to carry out similar
experiments with farm animals.
The scientists are not sure why inflamed
organs become more vulnerable to prions,
but suspect it may be connected to the
immune reaction. When an organ is inflamed,
the immune system produces blood cells
called lymphocytes to help battle the disease.
These cells produce a substance called
lymphotoxin, which Aguzzi says may trigger
a reaction that turns a normal cell into one
capable of replicating prions. His lab has
found that mice lacking the lymphotoxin
receptor lack prion disease in inflamed
organs.
Journal reference: Science (DOI: 10.1126/science.1106460)
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