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Prions, Nearly Indestructible and Universally Lethal, Seed the Eyes of Victims

blogs.scientificamerican.com

91–100 of 195 posts

Re: Prions, Nearly Indestructible and Universally Lethal, Seed the Eyes of Victims

#91
post #76

Earlier quoted context omitted.

Well the immune system needs to be able to do something of use in response. Just putting it in even with an immune sensitizing agent would add another prion that it can't do anything useful about. But antibodies, if we had ones that worked for a strain and weren't essentially prions themselves we could vaccinate for it or use it to "chelate" assuming the prion grabbers wouldn't cause other unacceptable problems.

Passive immunization might indeed be a feasible option, but of course requires timely detection.

Couldn't we immunize before exposure as we do with, say polio, TB, influenza et al? Then no detection would be needed.

Or are the abnormal prions in CJD and the like not uniform enough for general prophylaxis?

I really have a naive understanding of immunotherapy, so sorry if my question is dumb.

Re: Prions, Nearly Indestructible and Universally Lethal, Seed the Eyes of Victims

#92

I had project in college on Prions. Some interesting things I remember: * Kuru (laughing disease) was transmitted from cannibalism. Women and children of the tribe were more likely to contract it because they were more often given the less palatable parts of the bodies, which included brains * Some countries do not trust American cattle because our standards for Prion screening are too low * Kentucky has issues with…

Eating sheep's brain is pretty common in certain parts of India

Is it a big issue out there?

If I've eaten sheeps brain twice myself, how soon should I plan my funeral?

Re: Prions, Nearly Indestructible and Universally Lethal, Seed the Eyes of Victims

#93
post #10

Prion disease is exceedingly rare. CJD is the most common, with an incidence of 1 per 1,000,000 person-years worldwide, inclusive of all transmission vectors (including medical procedures). Iatrogenic transmission is a rarer subset still: the riskiest transplants (with respect to CJD) are in the central nervous system. The UK tracked their transmission rates from 1970 to 2003 (a long period is needed because surgical…

There is a great hypothesis that I remember my dad telling me recently, although I can't remember where he heard it from, that the reason that prion disease is so rare in humans is because we're, historically, very cannibalistic, so resistance to prions was heavily selected for.

Re: Prions, Nearly Indestructible and Universally Lethal, Seed the Eyes of Victims

#94

I had project in college on Prions. Some interesting things I remember: * Kuru (laughing disease) was transmitted from cannibalism. Women and children of the tribe were more likely to contract it because they were more often given the less palatable parts of the bodies, which included brains * Some countries do not trust American cattle because our standards for Prion screening are too low * Kentucky has issues with…

> Try not to eat animal or human brains Now all I can think about is the dinner scene at the end of Hannibal.

One of the Indiana Jones movies featured a monkey brain dish... blech

Re: Prions, Nearly Indestructible and Universally Lethal, Seed the Eyes of Victims

#95
post #49

Earlier quoted context omitted.

Just when I thought my home state couldn't embarrass me more by being backwards... Thanks!

Aw don't be embarrassed. It's a cool little bit of history. Growing up in the bible belt, I remember many charity events were accompanied by a stew. You could buy it by the quart. My local volunteer fire department made a stew twice a year and everyone in the community looked forward to it. My grandfather and father used to cook stews for my birthday. The act of cooking a stew was an all day affair and pretty fun by…

That group cooking is super cool.

I am going to arrange a family event where that happens.

Re: Prions, Nearly Indestructible and Universally Lethal, Seed the Eyes of Victims

#96

Earlier quoted context omitted.

Same here. I've had strange eye problems that my doctor hasn't been able to explain, and I feel like my cognition is declining. It's easy to buy into unknowns like this which seem to explain everything wrong with you, but it's exceedingly unlikely. More likely is that my eye problems are from wearing contacts in for too long and staring too long at a computer in a low-humidity environment and never blinking. My cogni…

> I've had strange eye problems that my doctor hasn't been able to explain, and I feel like my cognition is declining You could also explain this with low-level heavy metal exposure, e.g. mercury, as well as a large amount of other possibilities :-) I thought hard if I should write this, as a joke and only the above line at first, but here it goes. Having read your second paragraph too, that is pretty much exactly wh…

Can I ask how you were exposed to mercury?

Re: Prions, Nearly Indestructible and Universally Lethal, Seed the Eyes of Victims

#97
post #89
post #83

Earlier quoted context omitted.

They don't replicate. Prions can't themselves make more prions like viruses do.

They can induce correctly-folded proteins to misfold, effectively replicating.

But shouldn't the number of misfolds be very limited or just one so that evolution cannot occur? It almost sounds like fearing that fire will evolve.

Re: Prions, Nearly Indestructible and Universally Lethal, Seed the Eyes of Victims

#98
post #39

Earlier quoted context omitted.

Cooked goat and cow heads are a delicacy in some regions of Tunisia. Obviously, this includes the brain. I now wonder if Prions have ever been an issue in Tunisia...

Goat heads in Iceland too.

Calve's brains in Quebec.

Re: Prions, Nearly Indestructible and Universally Lethal, Seed the Eyes of Victims

#99
post #42
post #30

Earlier quoted context omitted.

There are plenty of ways that a protein could be mis-folded. There is a lot of bumpiness in a cell (though this is unlikely to lead to this). A random mutation (through some sort of radiation) could change a piece of DNA or RNA, causing the protein to be made incorrectly. All of these are frighteningly unlikely. But happen so often they are almost certain to do so in a large enough time, with a large enough populatio…

"Prions don't really suggest that life is a simulation." If life is a simulation, prions suggest either the simulation is run at an extremely high degree of verisimilitude, indeed simulating QM at a particle level for living things, or that the simulator has an incredible desire for accuracy, and has put a lot of non-trivial work into ensuring it. Almost anything you can think of that would reduce the computational l…

>If life is a simulation, prions suggest either the simulation is run at an extremely high degree of verisimilitude, indeed simulating QM at a particle level for living things, or that the simulator has an incredible desire for accuracy,

These are both somewhat my logic for even believing we live in a simulation. Obviously humans seem to be the largest factor on Earth given how we are rapidly changing the planet and directly, and indirectly, affecting all life on the planet.

We already have things like folding@home, weather modelling, climate modelling, asteroids@home, cosmology simulations from universe sandbox to supercomputer level, etc etc so on and so forth.

People love to immediately dismiss a simulation hypothesis "stuff is too detailed!" "why would someone use such specificity!". Well, why would anyone watch the Kardashians or eat hair (Trichophagia) or smoke cigarettes because none of these things are rational... however having a highly detailed simulation has all sorts of potential applications from seeing how ancestors may have evolved to seeing how a designer organism might potentially play out on a sterile world you plan to seed to being someone's incredible version of the Sims.

I mean, WE have the desire to do this sort of stuff. The above mentioned distributed computing and supercomputer applications shows some level of desire for this sort of thing but then you have games like SimLife from 1992 that allowed players to simulate an ecosystem and to modify the genetics of the plants and animals in the game.

'Junk' DNA, prions, viruses, erm consciousness, burning fossil fuels to the tune of roughly 40 gigatons of carbon dioxide emissions this year, living in coastal cities at or below sea level even AFTER disasters do considerable damage, the rapid adoption of social media and reality television, all of these things seriously make me wonder if we in fact are some sort of simulation just to see how a species can deal with both environmental and self-caused disasters.

Throw in many other things like the fact we've not detected life off-world, we've yet to detect any signs of another intelligent species (mind you we're just starting to really look), the rapid advances we've made in technology just in the 33 years of my life, technology allowing for us to fake audio and video of people that enough reference data exists for and things like this Chinese virtual news anchor, etc and it becomes really easy to go "huh, maybe we DO live in a simulation".

Re: Prions, Nearly Indestructible and Universally Lethal, Seed the Eyes of Victims

#100
post #21

Earlier quoted context omitted.

We take measures now, for tissues where prions are a possible transmission risk. The article mis-represented that. But: (1) there are only so many resources to go around. Should we be devoting them to vanishingly rare things rather than things that might actually affect you? (2) prions will never be a wildfire plague. They have little or no tranmissive ability, by nature of being absolutely naked protein. One step up…

The example in the article has very little transmissive ability because it grows in the brain and eyes. If there were a respiratory prion disease that could be much different. By nature of being a protein they are simpler and harder to eliminate than bacteria or viruses: > In a particularly vexing twist, prions are also nearly impervious to destruction, even when attacked using a strenuous combination of disinfectant…

How is this at all a "twist"? The reason you cannot deactivate prions using these methods is that they are meant to denature protein. Prions are "amyloids"/beta-sheets, which means they are already in the lowest-energy state. This lowest-energy-state is exactly why the presence of prion can serve as a nucleation point for other proteins to denature into beta-sheets.
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