SEARCH VEGSOURCE:

 

 

Follow Ups | Post Followup | Back to Discussion Board | VegSource
See spam or
inappropriate posts?
Please let us know.
  




From: Terry S. Singeltary Sr. (216-119-143-29.ipset23.wt.net)
Subject: New study shows how mad cow prions hitch a ride into intestine
Date: December 14, 2004 at 5:22 pm PST

-------- Original Message --------
Subject: New study shows how mad cow prions hitch a ride into intestine
Date: Tue, 14 Dec 2004 19:17:16 -0600
From: "Terry S. Singeltary Sr."
Reply-To: Bovine Spongiform Encephalopathy
To: BSE-L@LISTSERV.KALIV.UNI-KARLSRUHE.DE


##################### Bovine Spongiform Encephalopathy #####################

Public release date: 14-Dec-2004


Contact: George Stamatis
George.Stamatis@case.edu
216-368-3635
Case Western Reserve University


New study shows how mad cow prions hitch a ride into intestine


They piggyback on iron-storing proteins after surviving digestive juices

A new study from the Department of Pathology at Case Western Reserve
University School of Medicine shows that the infectious version of prion
proteins, the main culprits behind the human form of mad cow disease or
variant Creutzfeldt-Jakob Disease (vCJD), are not destroyed by digestive
enzymes found in the stomach. Furthermore, the study finds that the
infectious prion proteins, also known as prions, cross the normally
stringent intestinal barrier by riding piggyback on ferritin, a protein
normally absorbed by the intestine and abundantly present in a typical
meat dish. The study appears in the Dec. 15 issue of the Journal of
Neuroscience.

Prions are a modified form of normal proteins, the prion proteins, which
become infectious and accumulate in the nervous system causing fatal
neurodegenerative disease. Variant CJD results from eating contaminated
beef products from cattle infected with mad cow disease. To date, 155
cases of confirmed and probable vCJD in the world have been reported,
and it is unclear how many others are carrying the infection.

According to the study's senior author Neena Singh, M.D., Ph.D.,
associate professor of pathology, little is known about the mechanism by
which prions cross the human intestinal barrier, which can be a
particularly difficult obstacle to cross.

"The mad cow epidemic is far from over, and the continuous spread of a
similar prion disease in the deer and elk population in the U.S. raises
serious public health concerns," said Singh. "It is therefore essential
to understand how this disease is transmitted from one species to
another, especially in the case of humans where the infectious prions
survive through stages of cooking and digestion."

Using brain tissues infected with the spontaneously occurring version of
CJD which is also caused by prions, the researchers simulated the human
digestive process by subjecting the tissue to sequential treatment with
digestive fluids as found in the human intestinal tract. They then
studied how the surviving prions are absorbed by the intestine using a
cell model. The prions were linked with ferritin, a cellular protein
that normally binds excess cellular iron to store it in a soluble,
non-toxic form within the cell.

"Since ferritin shares considerable similarity between species, it may
facilitate the uptake of prions from distant species by the human
intestine,"said Singh."This important finding provides insight into the
cellular mechanisms by which infectious prions ingested with
contaminated food cross the species barrier, and provides the
possibility of devising practical methods for blocking its uptake," she
said. "If we can develop a method of blocking the binding of prions to
ferritin, we may be able to prevent animals from getting this disease
through feed, and stop the transmission to humans."

Currently, Singh's group is checking whether prions from distant species
such as deer and elk can cross the human intestinal barrier.

###
The study was supported by National Institutes of Health grants.

http://www.eurekalert.org/pub_releases/2004-12/cwru-nss121304.php

TSS

############## BSE-L-subscribe-request@kaliv.uni-karlsruhe.de ##############


re-pig and chicken feed with ruminant material, so much for that
circle of death. The late great Joe Gibbs was correct about that
as well...TSS



Follow Ups:



Post a Followup

Name:
E-mail: (optional)
Subject:

Comments:

Optional Link URL:
Link Title:
Optional Image URL: