MAd Cow

[scrambler]

Here's an interesting but tragic side note: Disorder Steals Soldier's Mind, Life

[Fairweather]

Good info, Catbird. I've been drastically reducing my beef intake for a couple years now (almost to zero now anyway) and this just about settles it for me. It seems that the beef industry hasbeen negligent in not wholly stopping the use of animal renderings in cattle feed. If they can't get their shit together - and it seems now that they never will - I won't allow my kids to eat it (in their school lunches) either.

 

Fish: PCB's and heavy metals

Chicken/Poultry: Irradiated (The jury's still out on this)

Pork: The other white meat

Beef: Brain wasting disease

 

DAMN! I swore I'd never go 100% vegetarian, but I'm giving it serious consideration.

[Dru]

doesn't take much skill or firepower to hunt a carrot

[Dru]

try free range organic, it costs more, you eat less, it tastes better....

[Fairweather]

doesn't take much skill or firepower to hunt a carrot

 

...or to kill a cow in a slaughterhouse.

[scrambler]

The only way to kill it is to incinerate it.

 

Bar-B-Que

[catbirdseat]

All kidding aside, do I think Americans should worry about eating beef? I think the answer is no. Your chances of getting VCJD are much less than getting cancer or getting struck by lightning. People should not change my habits based on the discovery of one infected cow.

[minx]

i did my senior research on BSE. it was quite interesting and based on what i learned that year if i still ate beef this lone case would do nothing to change my interest in eating beef. there are plenty of other good reasons not to eat mass produced beef. Try organic or free range beef.

[Jim]

All kidding aside, do I think Americans should worry about eating beef? I think the answer is no. Your chances of getting VCJD are much less than getting cancer or getting struck by lightning. People should not change my habits based on the discovery of one infected cow.

 

Take a read of Fast Food Nation. That will cure you of any beef craving, from the industrial lot anyway.

[Thinker]

[chucK]

I read the article yesterday and all it said was "this is not terrorist related " and "because the cow was injured it was not destined to be slaughtered" . This was a big point in Fast Food Nation, that rules such as not using diseased, injured, dead cattle for meat production are routinely flaunted.

 

Check out that link today. Obviously the story has morphed. Also check out this one. The cow was slaughtered. The initial reports of "no worries just one cow" blah blah blah appear now to have been just another cover story? Or are the new worries just media hype? Appears either way it's already hurt the US beef industry. Seven countries, so far, have banned the import of US beef.

 

Hey RobBob, is it still "not PC" to eat beef now that Fox News is doing a story on BSE in the US?

[chelle]

Seriously though, I'm reading from the original story that there is no threat to the food supply so domestic consumption is not fatally threatened rather the impact will be felt economically in trade.

 

The crux of the problem is the long incubation period between initial infection and subsequent deterioration. So, an infected animal that does not exhibit visible symptoms is the host carrier. Why isn't there some sort of early warning test to determine the presence of the virus? Will implementing this be too costly in itself, for example, price beef beyond the reach of ordinary consumers?

 

No threat to the food supply because they "removed all diseased parts before they could enter the food supply." That's nuts in my opinion. Why not destroy the whole cow. They simply removed the brain, spinal cord, intestines, etc. before the sent the rest to be ground into hamburger. From what I know this is what they normally do to cows before grinding them up, so what was different from anyother processing day at the slaughterhouse?

 

Also, BSE and CJD are not caused by viruses. They are caused by prions, an protein organism that is not well understood, and mimics naturally ocurring protiens in mammalian brains in it's chemical structure, it is just a different shape. And it causes the normal proteins to adopt the new shape, causing the disease. It's been compared to an enzyme.

[catbirdseat]

Ehmic, are you familiar with the concept of "autocatalysis"? That's what it is. A, the normal protein, is converted to B, the abnormal one. The reaction can't go by itself, it is kinetically unfavorable (although it is thermodynamically favorable), but will go in the presence of a catalyst. In autocatalysis, the product, B, is the catalyst. So B catalyzes the production of itself from A. The more B, the faster A is converted. Wicked.

[Bronco]

I've had mean cows chase me from time to time while crossing farmer's fields to fish in their streams, but other than that, I ain't scared of cows.

[chelle]

Catbird. Thanks for clarifying that one for me. Maybe you could clear up the latest quote from Donald the great. "There are known knowns and known unknowns. And then there are unknown unknowns..."

[catbirdseat]

Did he mention unknown knowns? That's the only permutation that doesn't exist.

[arlen]

No threat to the food supply because they "removed all diseased parts before they could enter the food supply." That's nuts in my opinion. Why not destroy the whole cow. They simply removed the brain, spinal cord, intestines, etc. before the sent the rest to be ground into hamburger. From what I know this is what they normally do to cows before grinding them up, so what was different from anyother processing day at the slaughterhouse?

 

Sounds like they sent the sample to the lab because the cow looked sick; thus they didn't know it was BSE until processing was done. That's what NPR is reporting, anyway.

[scrambler]

Seriously though, I'm reading from the original story that there is no threat to the food supply so domestic consumption is not fatally threatened rather the impact will be felt economically in trade.

 

The crux of the problem is the long incubation period between initial infection and subsequent deterioration. So, an infected animal that does not exhibit visible symptoms is the host carrier. Why isn't there some sort of early warning test to determine the presence of the virus? Will implementing this be too costly in itself, for example, price beef beyond the reach of ordinary consumers?

 

No threat to the food supply because they "removed all diseased parts before they could enter the food supply." That's nuts in my opinion. Why not destroy the whole cow. They simply removed the brain, spinal cord, intestines, etc. before the sent the rest to be ground into hamburger. From what I know this is what they normally do to cows before grinding them up, so what was different from anyother processing day at the slaughterhouse?

 

Also, BSE and CJD are not caused by viruses. They are caused by prions, an protein organism that is not well understood, and mimics naturally ocurring protiens in mammalian brains in it's chemical structure, it is just a different shape. And it causes the normal proteins to adopt the new shape, causing the disease. It's been compared to an enzyme.

 

Yeah, it's a prion, which I understand to be a self-replicating infectious protein. The terms, carrier and incubation time are applicable in discussing the disease vector.

 

As far as the 'species barrier' this appears to have been breached. Pigs and other animals including fowl can contract prions from other host animals. The reason for not seeing the full blown symptoms is that these animals are slaughtered before the end of the incubation period.

 

The disease is always fatal. Anybody for Russian roulette?

 

We're going to see a lot of spin on both sides of the story.

[glacier]

Funny, I was talking with my folks on this in October - They are retired cattle ranchers, and we had just seen a talk in marketing of beef sales to South Korea and Japan - the two countries make their largest beef imports from the U.S - both high-end beef, as well as 'second' cuts, like skirt steak (diaphram) and tongue - But both are also insular markets, sensitive to real or perceived threats to the health of their own industry.

 

Long and short of it - Canada had one case of mad cow a couple years ago, and Japan has not imported beef from them since. My folks were disbelieving that it could happen here. The day after our BSE-suspect cow shows up, Japan shuts up down.

 

It's a difficult path to walk - we need to better fund and improve inspections, but not so much that the costs potentially cripple our own market - at this point, I'm not sure that the existing testing is statistically significant enough to protect the foodsource.

 

Was watching local coverage of the cow this AM, and traced the path of the carcass/meat. Yakima to Moses Lake to Centralia to Portland. about 400 miles. In a couple of days. The speed and distance (average of 800 miles producer to consumer) at which our food is distributed is a definite weak link.

 

newsflash - beef ban up to 12 countries (mostly Asia and South AM) - Europe already banning/limiting imports due to growth hormone use.

[JayB]

Ehmic, are you familiar with the concept of "autocatalysis"? That's what it is. A, the normal protein, is converted to B, the abnormal one. The reaction can't go by itself, it is kinetically unfavorable (although it is thermodynamically favorable), but will go in the presence of a catalyst. In autocatalysis, the product, B, is the catalyst. So B catalyzes the production of itself from A. The more B, the faster A is converted. Wicked.

 

"J Biol Chem. 2003 Dec 10 [Epub ahead of print]. Related Articles, Links

 

 

Autocatalytic conversion of recombinant prion proteins discplays a species barrier.

 

Baskakov IV.

 

Medical Biotechnology Center, University of Maryland Biotechnology Institute, Baltimore, MD 21201.

 

The most unorthodox feature of the prion disease is the existence of an abnormal infectious isoform of the prion protein, PrP(Sc). According to the protein-only hypothesis, PrP(Sc) propagates its abnormal conformation in an autocatalytic manner using the normal isoform, Pr P©, as a substrate. Because autocatalytic conversion is considered to be a key element of prion replication, in this study we tested whether in vitro conversion of recombinant PrP into abnormal isoform displays specific features of an autocatalytic process. We found that recombinant human PrP formed two distinct beta-sheet rich isoforms, the beta-oligomer and the amyloid fibrils. The kinetics of the fibrils formation measured at different pH values were consistent with a model in which the beta-oligomer was not on the kinetic pathway to the fibrillar form. As judged by electron microscopy, an acidic pH favored to the long fibrils, whereas short fibrils morphologically similar to prion rods were formed at neutral pH. At neutral pH the conversion to the fibrils can be seeded with small aliquots of preformed fibrils. As small as 0.001% aliquot displayed seeding activity. The conversion of human PrP was seeded with high efficacy only with the preformed fibrils of human but not mouse PrP and vice versa. These studies illustrate that in vitro conversion of recombinant PrP displays specific features of an autocatalytic process and mimics the transmission barrier of prion propagation observed in vivo. We speculate that this model can be used as a rapid assay for assessing the intrinsic propensities of prion transmission between different species."

 

I'll have to read up on this one a bit more but It'd be interesting to see if there has ever been a study in which purified prion protein delivered orally to test animals has resulted in an infection. I've seen a few papers where they injected cell-lysates directly into animals and generated the disease, but this hardly excludes other vectors. It would be amazing to me if there was a protein out there that could survive being cooked, resist degredation by pepsin and acidity in the stomach, pass through the intestine intact, pass into the bloodstream as an intact protein rather than a polypeptide, exist in the bloodstream as an intact foreign protein witout provoking antibody generation, make it through the liver unmodified, ultimately be transported from the bloodstream and across the cell membrane, and then persist in the cells without being tagged by kinases for import into lysozomes for destruction, or attack by proteases in the cytosol.

[catbirdseat]

"It would be amazing to me if there was a protein out there that could survive being cooked, resist degredation by pepsin and acidity in the stomach, pass through the intestine intact, pass into the bloodstream as an intact protein rather than a polypeptide, exist in the bloodstream as an intact foreign protein witout provoking antibody generation, make it through the liver unmodified, ultimately be transported from the bloodstream and across the cell membrane, and then persist in the cells without being tagged by kinases for import into lysozomes for destruction, or attack by proteases in the cytosol. "

 

Jay, PrP(Sc) is such a protein. The article you cited is significant. It means that you can test more easily which species prion diseases are transmissible to humans by doing it in vitro rather than by attempting to infect animals. Obviously, there aren't any humans lining up to see if sheep prion (scrapie), or cattle prion is infectious.

[JayB]

Have you seen any papers where they administer purified radioloabelled prion proteins to test animals orally and then find both the intact protein localized in brain tissue as well as the plaques of aberrant prion protein? Or where they administered unlabelled protein and detected it in tissue sections with F.I.S.H. or some other means? I haven't come across any papers like that that have would support the claim that prions can move from hamburger to brain - but I would think that there must be such papers out there if this transmission model has been universally accepted.

 

I'm also curious about the incidence of CWD in wild deer and sheep, as they surely are not grilling each other up in the wilderness or engaging in the ritual cannibalism that spread Kuru. The only model of transmission that would jive with this model is if the wild animals were getting their hands on tainted-feed destined for cattle and the species-barrier was too low to prevent transmission from cattle remains to Deer and Elk. I suppose it could pass from mother to offspring (?)but you'd think that natural selection would put a damper on this mode of transmission pretty quickly.

[murraysovereign]

The only model of transmission that would jive with this model is if the wild animals were getting their hands on tainted-feed...

 

When the Alberta Mad Cow was diagnosed, I recall reading a news piece in which they discussed animals being infected simply by grazing. These prions, as has already been mentioned, are remarkably persistent, and can be present in the grasses the animals are feeding on. For instance, infected deer dies and decomposes. Prions are introduced into the local environment, scattered about by wind, predators, etc., and then taken up by another animal grazing in that same pasture. That animal, now infected, wanders off and sometime (years?) later dies and decomposes, infecting a second pasture miles away from the first. And so on... They are, inadvertently, eating contaminated feed. It's organic, free-range contaminated feed rather than the industrial variety, but the end result is the same.

[chelle]

Have you seen any papers where they administer purified radioloabelled prion proteins to test animals orally and then find both the intact protein localized in brain tissue as well as the plaques of aberrant prion protein? Or where they administered unlabelled protein and detected it in tissue sections with F.I.S.H. or some other means? I haven't come across any papers like that that have would support the claim that prions can move from hamburger to brain - but I would think that there must be such papers out there if this transmission model has been universally accepted.

 

I'm also curious about the incidence of CWD in wild deer and sheep, as they surely are not grilling each other up in the wilderness or engaging in the ritual cannibalism that spread Kuru. The only model of transmission that would jive with this model is if the wild animals were getting their hands on tainted-feed destined for cattle and the species-barrier was too low to prevent transmission from cattle remains to Deer and Elk. I suppose it could pass from mother to offspring (?)but you'd think that natural selection would put a damper on this mode of transmission pretty quickly.

 

Jay - people aren't routinely eating cattle feed from what I understand. If you think BSE can't survive digestion how is it that the consumption of diseased beef (deer or elk) and CJD are linked?

[Thinker]

I'm way out of my field here, but I would suspect that handling the raw meat could be a transmission mode.