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Prions in Muscle Tissue

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Mike

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Advances in Understanding the Nature and
Behavior of the Agent

9:00 Welcome by Session Chairperson
Dr. Paul W. Brown

9:15 De novo Generation of Mammalian Prions
Dr. Giuseppe Legname, Institute for Neurodegenerative Diseases, University of California at San Francisco
A long-standing issue in the study of prion diseases, or transmissible spongiform encephalopathies, has been the formal proof that such disorders are indeed caused solely by conformation changes in the prion protein (PrP). In order to test the protein-only hypothesis we polymerized N-terminally truncated MoPrP(89-230) into amyloid and bioassayed the samples in transgenic (Tg) mice expressing MoPrP(89-230) (Tg(MoPrP,?23-88)9949/Prnp0/0). All of these Tg mice developed neurologic dysfunction between 380 and 660 days after inoculation, while control Tg mice inoculated with phosphate-buffered saline solution remained healthy for 670 days before sacrifice. Western blotting of brain extracts showed protease-resistant PrPSc; serial transmission of the brain extracts to wt FVB and Tg(MoPrP)4053 mice resulted in incubation times of 160 and 90 days, respectively. Prions generated de novo were compared to RML, which represents a well-characterized mouse scrapie strain. At least two new strains with different biochemical, biophysical and neuropathological characteristics were created. Our results support the propositions that prions are infectious proteins and that sporadic prion disease requires only the spontaneous conversion of PrPC into PrPSc.

9:45 In Vitro Generation of Infectivity by Protein Misfolding Cyclic Amplification (PMCA) and Use for Prion Detection in Blood
Dr. Claudio Soto, Professor, Neurology, University Of Texas Galveston

10:15 Early Events during TSE Infection
Dr. Suzette Priola, National Institutes of Health, NIAID, Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories
Despite the fact that normal protease-sensitive prion protein (PrP-sen) is required for infection with transmissible spongiform encephalopathy (TSE) agents, not all PrP-sen expressing cells are susceptible to TSE infection. In order to determine why TSE infection appears to be restricted to certain cell types, we have developed a tissue culture system that allows us to monitor both acute and persistent formation of protease-resistant prion protein (PrP-res), the form of PrP associated with TSE diseases. Our results demonstrate that, while any cell type can make PrP-res acutely, only certain cell types can make PrP-res persistently and become chronically infected with TSE agents. The data suggest that infection with TSE agents is a two-stage process involving a cell type-independent phase of acute PrP-res formation followed by a cell type-dependent phase of persistent PrP-res formation and infection.

10:45 Coffee Break, Poster and Exhibit Viewing

11:15 Transmission of Human TSE Diseases to Bank Voles
Dr. Maurizio Pocchiari, Director of Research Virology, Istituto Superiore di Sanita, Italy
Rodent models of human transmissible spongiform encephalopathy (TSE) represent a valuable tool for characterising human isolates, but primary inoculations have always resulted in a low rate of transmission and long incubation periods. We found that the wild rodent bank vole (C. glareolus) is highly susceptible to some forms of sporadic and genetic Creutzfeldt-Jakob disease with incubation periods shorter than 180 days. These rodents may be valuable for strain typing human TSE diseases. Co-Authors: Vaccari G., Di Bari M.A., Simson S., Frassanito P., Nonno R., Cartoni C., Borroni R., Cardone F, Agrimi U.

11:45 Studies on Pathogenesis, with Special Attention to Muscle Involvement
Dr. Michael Beekes, Robert Koch Institute, Germany
PrPTSE, the biochemical marker for infectious agents causing transmissible spongiform encephalopathies (TSEs) or prion diseases, can be detected in muscle tissue, not only at late stages of disease, but already before clinical symptoms become visible. Using different detection methods, such as Western blotting, immunohistochemistry or PET blotting the location of disease-specific prion protein in muscles, nerves and lymphoid tissue can be visualized in order to track down the routing pathways and reservoirs of TSE agents in the body. Experimental rodent studies are expected to provide further conceptual insights into the pathophysiology of TSE infections and may contribute to a better assessment of the risks for public health possibly emanating from "prions in skeletal muscle".

12:15 Pathologic PrP Deposition at the Cerebral Subcellular Level
Dr. Herbert Budka, Medical University of Vienna, Austria
We examined co-localization patterns of distinct PrPsc immunodeposits with cellular markers by confocal laser microscopy in CJD brains. PrPsc co-localizes most prominently with chemical synapses, but also electric synapses, neuronal somata, dendrites, axons, astrocytes, and microglia harbor PrPsc. Axons, shown for the first time in human disease to contain PrPsc, may be a relevant route of prion spread, and activated microglia and astrocytes may contribute to PrPsc processing or degradation.

12:45 Luncheon Technology Workshop Sponsored by

Enhancing Robust BSE Testing With Automation
Mr. Chris Neary, General Manager, Beckman Coulter, Inc
 
A

Anonymous

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That will be wonderful research to reflect back on when a disease similar to BSE rears it's ugly head again. BSE is almost history!



~SH~
 

Mike

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~SH~ said:
That will be wonderful research to reflect back on when a disease similar to BSE rears it's ugly head again. BSE is almost history!



~SH~

Yea, and that's exactly what the UK said in 1988 when they installed the feed ban. 40,000 cases born after the ban says they are not so sure that was the proper statement.
 

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Search for BSE in muscle meat draws blank

Tests by government scientists in France have allayed renewed fears that eating beef can cause variant Creutzfeldt Jakob Disease, the human form of BSE. The fears were heightened on 18 March when scientists unexpectedly reported finding traces of infective material in the muscles of mice.

The findings carried extra weight because they came from the lab of Stanley Prusiner, the scientist at the University of California in San Francisco who won a Nobel Prize for discovering mutated "prions". These are the defective proteins believed to cause brain-wasting diseases like BSE, vCJD and scrapie.

Prions are known to collect in brains, spinal cords, spleens and other lymphoid tissue and these parts have long been banned for human consumption. Muscle tissue in meat was assumed to be free of prion contamination and safe to eat.

But Prusiner's team found prions in the hind leg muscles of mice whose brains had been injected with BSE-like prions. He reported his results in Proceedings of the National Academy of Sciences.

Complete blank
The new twist in the story came on Wednesday, when French government scientists announced that they had drawn a complete blank when they looked for prions in muscles from several BSE or scrapie-infected animals including mice, sheep, goats and cows.

"The tests proved negative in the search for pathological prions in the set of samples, including those taken from the hind limb muscles," says the AFSSA, France's food safety watchdog.

Reassuringly, tests on peripheral nerves and lymphoid tissue in the cow also came up negative, suggesting that meat will be safe even if it contains this type of tissue. "These observations are consistent with the findings made to date concerning the distribution of the infectivity linked to BSE in cows," they say.

The researchers detected prions with two tests. The first, an "ELISA" test, detects antibodies made by animals against prions. The second "Western blotting" test isolates and identifies fragments of the prion protein itself. The scientists will discuss their results in more detail at a meeting of France's top BSE specialists on 11 April.

Low level infectivity
The significance of Prusiner's results has also been questioned in Britain. Peter Smith, chairman of the government's Spongiform Encephalopathy Advisory Committee, told New Scientist that a much more significant experiment had been under way for five years in Britain, and had yet to give any cause for concern.

Instead of using a surrogate animal like the mouse, this experiment is focusing on which cattle tissues can transmit BSE to other cattle. Scientists at the Veterinary Laboratories Agency in Weybridge, Surrey, injected the brains of live calves with liquidised tissue from various parts of the bodies of BSE-infected cows.

"None injected with muscle have gone down yet," says Smith. "But if you inject BSE-infected brain tissue, the calves come down with BSE in about two years, as expected," he says.

"If there is infectivity in muscle, it must be at a much lower level than in other tissue, particularly that from the brain or central nervous system," says Smith. You can never prove a negative, he adds, but the results so far have been reassuring.
 

Mike

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Scientists find the pathological prion protein in skeletal muscles of hamster with scrapie


In the May 2003 issue of EMBO reports, researchers from the German Robert Koch Institute in Berlin report finding the pathological prion protein PrPSc in a wide range of skeletal muscles after feeding hamsters with prion-infected food. PrPSc is believed to be an essential - if not the sole - constituent of the agent that causes BSE in cattle, scrapie in sheep and Creutzfeldt-Jakob disease in humans.

The researchers fed Syrian hamsters with food pellets that contained mashed-up brain tissue from scrapie-infected hamsters. These hamsters developed symptoms of scrapie as expected and were put down at the terminal stage of the disease. The researchers used a highly sensitive method (Western blot analysis) to analyse concentrated extracts from different muscles in the animals. They subsequently detected the pathological prion protein in various types of skeletal muscle of the terminally-ill animals. A control group of uninfected hamsters did not show pathological prion protein in their muscle tissue.

"These results support and expand on recent observations by Stanley Prusiner and his colleagues, who found scrapie agent in the hind limb muscles of mice whose brains had been injected with prions," says Michael Beekes, researcher at the Robert Koch Institute in Berlin. Until recently, PrPSc has normally been found in the central nervous system or in the lymphatic system, for instance, but never in skeletal muscle.

Reference: Thomzig, A., Kratzel, C., Lenz, G., Krüger, D. & Beekes, M. Widespread PrPsc-accumulation in muscles of hamster orally infected with scrapie. EMBO reports 4, 5, (2003). (Advanced online publishing on April 11, 2003; published in print May 1, 2003.)
 

Mike

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Dueling studies? That's funny! My point is that for every study there is another that contradicts. Which one do we believe? As in all safety procedural
guidelines; Only the "Worst Case Scenario" will assure safety for all. Until all is known should we dismiss any studies? History will tell.
 

mrj

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Mike and reader 2 are some of the scientists you quote using or treating results from SCRAPIE prions the same as that from BSE prions?

It is my understanding, though I haven't recorded the sources of what I read, that the two are not the same and they acti differently in whether or not the prions form in the blood, muscle, or urine rather than only in the brain tissue.

I have a couple of web sites to check and will not have time to do so before Monday at best.

http://www1.umn.edu/eoh/hazards/hazardssite/prions/priona sorb.html.

Http://europa.eu.int/comm/food/fs/sc/ssc/out296_en.pdf

While it is interesting to read what even the fringe and non-mainstream people have to say, maybe we are giving short shrift to the researchers in the mainstream because they are not as "glamorous" or exciting in their results to date???

And, please relax, I'm not saying those you quote are fringe or non-mainstream, only making a general observation of many quotes in various places re. what is and is not known or accepted re. BSE and TSE's in general. Just asking for careful thought and consideration of ALL the "reports", as well as possible financial biases of the researchers promoting their tests, etc.

MRJ
 

Mike

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Actually MRJ, the scientists I quote are not really scientists at all. They are really plumbers from the local union hall who have been laid off and are picking up extra income.
They have no idea what the difference is between scrapie and BSE prions are and could care less. All they are in it for is the money. But since the pay is less than what they are accustomed to they are also moonlighting as PR reps for the NCBA.
 

Tam

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Most of the so called proof of Prions in the Muscle has been coming out of Stanley Prusiner. So I googled him and I found a very interesting article about the ego of the young Stanley Prusiner. Its titled "The Name of the Game is Fame but is it Science?" written in 1986. It tells the story of how Stanley would do a bit of research jump to a conclusion and release it to the press while his collaborators would quit because they knew they couldn't prove what he had just released or the other scientist was left to tell the press there was no PROOF to back up his story. It also says how he took another scientist work and renamed it and claimed he had discovered it, namely the PRION (formally known in the Science world as the SAF found by Ms. Pat Merz a researcher at IBR and predated Stanleys claims by a year.) The article also says how he was asked to referee a peers paper for the New England Journal he did and suggested it be rejected. Then he turn around, changed a few details as in the number of head tested and submitted it in his own name. Turns out his paper was rejected and the one he suggested be rejected was printed, because another one of his peers that knew about the first paper reviewed his paper. Since then he request on submission of an article for publication that it not be referee by his competitors.

And before you jump all over me I'm just paraphrasing what the article says. If true, I sure hope Stanley has changed with age because if he did these kinds of things to get to the top of the scientific food chain what is he willing to do to stay there when his publicity has got him multimillion dollar grants? So two questions come up question #1 is why after Stanley announced the information to the press about the Prions in the muscle meat has so many other scientist not found the same test results? And the other is If Stanley is wrong like he has been in the past what will his statements cost the beef industry before the rest of the scientific community is listened to? Oh maybe he is not being listen to as most of what you hear is that Beef is safe as the prions are not found in the Muscle meat of Cattle that have been natural infected.

You do not have to convince me, you have to convince the expert scientists that oppose Stanley's therioies and have for years. Those the rest of the world is looking to, to get the answers and the guidelines of how to protect all consumers.

The article is at http://slate.msn.com/id/2096/sidebar/42786/ if you care to read it, it is about 14 pages long.
 

Tam

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I told you before you don't have to convince me READER you have to convince all the scientists that have conficting studies to Prusiner to whom the rest of the world listens to. As if you can convince them you will be changing the way most government and the OIE see BSE :wink:

I did like the little limerick that was posted though

There was a young turk named Stan
Who embarked on a devious plan.
"If I simply rename it,
I'm sure I can claim it,"
Said Stan as he pondered his scam.

"Eureka!" cried Stan,
"I have found it. Well . . . maybe not actually found it.
But I talked to the press
Of the slow virus mess
And invented a name to confound it!"

And Reader if Stan was only one of the people why is his name on the Nobel Prize and not Pat Merz's. Other scientists studied her SAF and His Prion and claimed they were the same but Stanley refused to admit they were the same and claimed all the glory for himself.
Do you know very many of these breakthrough type scientists? Some good portion of them are driven, focused, ambitious, and even super competitive.
No I can't say I do know any but the ones that were quoted in the article seem to think Prusiner was a bit reckless with his claims of discovering something when he couldn't back them up.

Mike wrote
It's a twenty year old article. Anything newer?

Can you prove he has changed in the last twenty years when he is still releasing claims to the media that others scientist claim they can't verify?
 

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Interesting thread! Now we got Tam disproving Prusiner's theory and she's not even a scientist. She might get the "Wurlitzer" prize. :wink:
 

Tam

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reader (the Second Tam - Prusiner is not the sole recipient of the Nobel Prize for the discovery of prions. Go check your facts.[/quote said:
Prusiner Wins Nobel Prize
Victor Gonzalez ([email protected])
Mon, 6 Oct 1997 09:42:04 -0800

Messages sorted by: [ date ][ thread ][ subject ][ author ]
Next message: Victor Gonzalez: "Prusiner's Background"
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Corinna Kaarlela, Interim News Director
Source: Jeffrey Norris (415) 476-2557

MEDIA ADVISORY
October 6, 1997


UCSF DISCOVERER OF THE "PRION" WINS NOBEL PRIZE


Stanley B. Prusiner, MD, of the University of California San Francisco, was
awarded the Nobel Prize
in Physiology or Medicine today (October 6).


Prusiner, professor of neurology and biochemistry and biophysics at UCSF,
received the prize "for his pioneering discovery of an entirely new genre
of disease-causing agents and the elucidation of the underlying principles
of their mode of action," according to the Nobel committee in Stockholm,
Sweden

Dr. Prusiner is in Bethesda today attending a meeting of the Food and Drug
Administration Advisory Committee on Transmissible Spongiform
Encephalopathies. Media should contact him at the Holiday Inn, 8120
Wisconsin Avenue (301/652-2000).


THE UCSF CAMPUS WILL TOAST DR. PRUSINER IN HIS ABSENCE AS FOLLOWS. MEDIA
ARE INVITED TO COVER:


Monday, October 6
10:00 am
Room S-118, Medical Sciences Building
513 Parnassus
UCSF Campus, San Francisco


Prusiner discovered an entirely new disease agent, called a prion, which is
implicated in rare, slowly progressing brain diseases.

He has demonstrated that unlike other pathogens--bacteria, viruses,
protozoans and fungi--the prion contains no genetic material. It is mostly
a protein.


The prion is the infectious agent that causes scrapie, a disease of sheep
and goats, "mad cow disease," which has been epidemic among cattle in Great
Britain, and rare but fatal human diseases of the central nervous system.
These diseases are in some ways similar to Alzheimer's. They result in
dementia and death after a long process.


A better understanding of prion diseases may advance research into
neurodegenerative disorders, and could provide insight into the processes
by which nerve cells assume specific forms and functions, perform these
roles for decades, and then become senescent.


The correct name of the institution is the University of California San
Francisco.
Isn't this a press release from where he works and if anyone else got credit why weren't their names mentioned like maybe Pat Merz that worked for IBR and discovered the SAF years before Prusiner came up with the new name PRION according to his peers not me MIKE

Interesting thread! Now we got Tam disproving Prusiner's theory and she's not even a scientist. She might get the "Wurlitzer" prize.
Another comment from the sarcastic peanut gallery. :roll: Where was I proveing anything about his therioes I posted about expert scientist in the UK and France that contradict his theroies and a story about the ego of a man that in the past was caught with his hand in the publicity cookie jar when his peers thought he was taking sole credit where sole credit wasn't do if any. Man you are testy today Mike did you get up on the wrong side of the bed you snapped at MRJ for her civilly asked question and now this. :roll:
 

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