Counterpoint: The Fore people of NZ had kuru from ritual cannibalism. Then they stopped. Eventually, the disease stopped too. Prions are nasty, but we've had 3.5 billion years of protein folding and none of it has ended the world yet.
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Prions
171–180 of 184 posts
Re: Prions
#172Earlier quoted context omitted.
It appears that the first mention of scrapie in scientific literature is 1755, and the disease increased with inbreeding (and lessened when this practice was stopped): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1114482/ The wiki also indicates that a sheep vaccine distributed in 1935 caused an epidemic, as it contained contaminated neural tissue: https://en.wikipedia.org/wiki/Scrapie It also seems to me that the re…
This is a very interesting idea! But, is it known that macrophages are able to break down prions? My understanding of the problem is that part of it is that they're just quite hardy.
Even if they can't, it's probably better for them to build up in macrophages, dendritic cells, etc. rather than in neurons.
Re: Prions
#173Earlier quoted context omitted.
Also sarcasm
Whoosh! (me, LOL)
It's okay. Lack of sarcasm tells in textual format leads to Poe's Law. ;) I wish English had inline accessory indicators to tack on tone for context instead of ambiguous wording, especially for critical conversations (that probably should be had by phone or in-person). Perhaps emoji serve this purpose? Why not some sort of diacritics though?
Re: Prions
#174I remember that in the 90s, when "mad cow disease" was dominating the headlines, it was predicted that there would be an exponential increase in cases, decades down the line. The same point about prions being virtually indestructible was being made, the same concerns about surgical equipment and blood donations were raised. Suffice it to say, the prion disaster did not materialize, so I'm skeptical about the same sto…
We have no idea if US Beef is infected. The USDA prohibits anyone from testing their cows and ended their spot-testing program (which was a joke). So unlike Europe we never reckoned with the problem and don't know if it is currently spreading. For human exposure we would not yet be far enough along to know if the US Beef supply either is or was contaminated. Personally I have basically stopped eating beef for this re…
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Re: Prions
#175Earlier quoted context omitted.
Who knows. I'll give you an interesting thought. There is NO single, conclusive test for Alzheimer's disease. The symptoms are almost identical to CJD (human mad cow) with the biggest differentiator being time from diagnosis to death. Even Amyloid-beta plaque buildup is often (though not always) noted in CJD patients [0][2]. Likewise the other Alzheimer's marker tau protein is also elevated in CJD patients [3]. I'd n…
> The symptoms are almost identical to CJD (human mad cow) with the biggest differentiator being time from diagnosis to death. Ordinary CJD has a much lower median age of death (68 years) than Alzheimer's (88 years), but vCJD (the form that is believed to be caused by contaminated food) has a median age of death of only 28 years. https://en.wikipedia.org/wiki/Creutzfeldt%E2%80%93Jakob_dise... A surge in young or midd…
> You have mistaken the rate of deaths (per 100,000) for the percentage. When judging this increase, one must consider that in the same timeframe, the mean age of the population has risen by 10% and life expectancy increased by more than two years.
Sorry, knew what I meant, but messed up what I typed. In any case, doubling the death rate per 100k is still much greater than the 10% age and 2-3% lifespan increase would indicate. Alzheimer's mortality had increased 16x between 79 and 91 (from a mere 857 to 13,768 in 1991[0]. The previous study I quoted above put the 2018 mortality at 122,019. Alzheimer's is now the 6th leading cause of death and continues to rise at a rapid rate.
> Ordinary CJD has a much lower median age of death (68 years) than Alzheimer's (88 years), but vCJD (the form that is believed to be caused by contaminated food) has a median age of death of only 28 years.
This is the crux of the problem.
We have experimental knowledge about this from kuru. The last patient displayed symptomatic kuru some 5 decades after the cannibalistic practices had stopped.
Do only young people eat meat? If all age groups eat meat at equivalent rates and infection rates in cattle are constant (believed to be around 1 in a million IIRC), then the median age should be the population median age PLUS a shift for however long it takes to become symptomatic.
Linkage is also important. How do we know that CJD and vCJD are different? We made that distinction arbitrarily and don't have evidence that "normal" CJD is not caused by external sources. Official vCJD cases are around 200 over the past 30 years, so there isn't exactly huge amounts of data to pull from either.
If CJD really did explode in the 80s-90s, then you would expect the older generation to become symptomatic at an older age than would be typical if the disease were common in the decades before.
There seems to be a connection with being vegetarian/vegan and alzheimer's but how much is due to not eating meat and how much is due to overall healthy lifestyle is hard to determine.
Something weird is going on with Alzheimer's disease and the legit explosion in cases over the last 30 years (both per capita and as cause of death in the elderly) give reason to wonder what weirdness is going on.
Re: Prions
#176Prions used to bug me as an idea for quite a while when I was an undergrad. However, since I have worked in a biolab and I actually read material that isn't just fear mongering, I can tell you a ton of stuff that makes this article totally wrong.
Prions don't live forever, they are susceptible to soap and water. Prions are proteins, anything that can break down a protein will work to break down a prion. They are not some form of mystical protein. They will break down naturally over time. This is why regions that have had Kuru outbreaks have been able to stop those outbreaks.
Since prions are literally just a chemical (albeit a complex one), they are not trying to propagate themselves. There have been outbreaks, but no massive ones with prions because that's simply not how they work. As well, since they are proteins and proteins eventually break down when they are removed from a living being, they will also eventually break down.
This article is a whole lotta fear with not a whole lotta valid info.
Re: Prions
#177Earlier quoted context omitted.
Not meant as joke. I'm aware that there are lots of good reasons for not eating beef, I was wondering if prion exposure risk is one of them, as the meat/no-meat argument is one I try to revaluate regularly as new info comes to light. I eat beef once or twice a week as I have found it hard to get sufficient iron, protein, b12 and enough calories in general without it (and other meats). That and it tastes good, but I'm…
I don't think prion disease currently is a significant enough risk to make it an argument against eating meat. It's a rounding error compared to for instance increase in colon cancer I eat meat occasionally as well. I tried going vegetarian for a six months, but I lost an unhealthy amount of weight (my BMI dropped from 19.2 to 17.8) and I think the health risk from malnutrition, as you also mention having struggled w…
Yeah this is exactly the situation I find myself in. I regret the ethical and environmental consequences of eating meat, but I found it very hard to replace it completely and still have a balanced diet.
Re: Prions
#178Earlier quoted context omitted.
This is a very interesting idea! But, is it known that macrophages are able to break down prions? My understanding of the problem is that part of it is that they're just quite hardy.
Even if they can't, it's probably better for them to build up in macrophages, dendritic cells, etc. rather than in neurons.
Disagree. Every single antibody alzheimer's drug that has targeted the amyloid plaques and none of them have succeeded.
You're just as likely to elicit an immune response to the prion plaques, stabilize them, and recruit inflammation to the point of deposit, making matters worse.
Re: Prions
#179Earlier quoted context omitted.
Cwd is essentially the same as bse and cjd and scrapie. It's actually the one that you have to worry about the least. For unknown reasons, there is not species crossover between deer and cow/sheep/humans (I was briefly investigating the molecular mechanisms for this but finished my phd before getting results). As for why the grazing animals can spread prion, my guess is that the prion protein is highly concentrated i…
No lengua tacos? What will I get now?
Cabeza. Which is usually the cheek meat. Avoid sesos, of course.
Re: Prions
#180Earlier quoted context omitted.
This comment is spot on (I'm a former prion researcher).
What are your thoughts on the risks of AlphaFold and prions? It seems like prions don't have much chance to evolve/mutate naturally since any change makes them unable to duplicate. However with these simulation systems, are man-made prions a concern?
> naturally since any change makes them unable to duplicate.
That's not true.
Don't worry about alphafold. Even if it's a really good extrapolation engine (and not a really good interpolation engine) the amyloid fold is unusual enough that I doubt that alphafold can heuristically solve structures much less assess energetic or kinetic factors (which is not what it was designed to do). Note that I am an alphafold optimist and am on record here saying that I consider alphafold to have solved the basic protein folding problem. More to the point, we don't have many reliable solved structures of amyloid folds, it's clear that they are heterogeneous anyways, and iirc no one has bootstrapped an infectious prion in vitro, which means we don't know exactly what makes something infectious... We can make prion amyloid in vitro but it isn't infectious unless it was seeded by an infectious prion amyloid.