Mad Cow! MOOOOOOO!

[strawman]

http://www.cnn.com/2013/09/20/health/creutzfeldt-jakob-brain-disease/index.html?hpt=hp_t2

The Creutzfeldt Jakob disease commonly known as mad cow was found in a deceased patient in the US recently. Unfortunately that patient had a brain operation prior to discovering the disease. Even more unfortunately the equipment used during that operation was subsequently used, after having been cleaned, on up to 16 other patients having brain operations.

Most unfortunately of all, the normal sterilization procedures are not enough to destroy the prions that characterize the disease.

Time will tell if these patients contract the disease, but they have been notified.

There is no known cure or treatment and it is always fatal once contracted.

What surprises me is that after all the mad cow business over nearly the last two decades, we are still using surgical tool sterilization procedures that aren't sufficient to stop its spread.

Moo.

 

[redthirtyone]

 

[bhamv3]

Could be worse, here in Taiwan we had a case where the organs from a recently-deceased HIV-positive individual were given to five other patients for transplant. Imagine the doctor talking to the patient afterwards.

"Well Mr. Chang, it looks like your new liver's working quite well, no sign of rejection at all, congratulations! Also, you have AIDS."

 

[Bones]

they are going to have to add an acid bath to sterilization of tools used in brain surgery going forward.

 

[PatrThom]

I saw the story, and the big takeaway I got from it was that there are bad things that don't get destroyed by autoclaving, to which I said, "There are bad things that don't get destroyed by autoclaving???"

These spongiform deseases are all listed as "incurable," but I wonder how effective it would be to treat them with bexarotene and Vitamin A (two things which help boost the clearing of amyloid plaques in the brain).

--Patrick

 

[ThatNickGuy]

 

[PatrThom]

--Patrick

 

[GasBandit]

As I understand it, Prions are just misfolded protiens, not actual living things, so sterilization would be more difficult than what it takes to kill a virus or bacteria. I've always envisioned it as Ice-9 for the brain.

 

[PatrThom]

Right, they are mechanical in nature, not biological. I was more surprised that the proteins themselves were durable enough to survive autoclaving, which is basically pressure-cooking something at > 120°C/240°F for 20 minutes. You try to do that with even the toughest cut of beef and it'll come out of there like mush I stand corrected, there are recipes which actually recommend cooking some of the organ meats for over an hour.

--Patrick

 

[strawman]

Read the wikipedia entry on prions - very enlightening. Here's the summary excerpt, with some emphasis (by me):

A prion (i/ˈpriːɒn/[1]) in the Scrapie form (PrPSc) is an infectious agent composed of protein in a misfolded form.[2] This is the central idea of the Prion Hypothesis, which remains debated.[3] This would be in contrast to all other known infectious agents (virus/bacteria/fungus/parasite) which must contain nucleic acids (either DNA, RNA, or both). The word prion, coined in 1982 by Stanley B. Prusiner, is derived from the words protein and infection.[4] Prions are responsible for the transmissible spongiform encephalopathies in a variety of mammals, including bovine spongiform encephalopathy (BSE, also known as "mad cow disease") in cattle. In humans, prions cause Creutzfeldt-Jakob Disease (CJD), variant Creutzfeldt-Jakob Disease (vCJD), Gerstmann–Sträussler–Scheinker syndrome, Fatal Familial Insomnia and kuru.[5] All known prion diseases affect the structure of the brain or other neural tissue and all are currently untreatable and universally fatal.[6]

Prions, like viruses, are not actually alive, although both can reproduce by hijacking the functions of living cells.[7]

Prions propagate by transmitting a misfolded protein state. If a prion enters a healthy organism, it induces existing, properly folded proteins to convert into the disease-associated, prion form; the prion acts as a template to guide the misfolding of more proteins into prion form. These newly formed prions can then go on to convert more proteins themselves; this triggers a chain reaction that produces large amounts of the prion form.[8] All known prions induce the formation of an amyloid fold, in which the protein polymerises into an aggregate consisting of tightly packed beta sheets. Amyloid aggregates are fibrils, growing at their ends, and replicating when breakage causes two growing ends to become four growing ends. The incubation period of prion diseases is determined by the exponential growth rate associated with prion replication, which is a balance between the linear growth and the breakage of aggregates.[9] (Note that the propagation of the prion depends on the presence of normally folded protein in which the prion can induce misfolding; animals which do not express the normal form of the prion protein cannot develop nor transmit the disease.)

This altered structure is extremely stable and accumulates in infected tissue, causing tissue damage and cell death.[10] This structural stability means that prions are resistant to denaturation by chemical and physical agents, making disposal and containment of these particles difficult. Prions come in different strains, each with a slightly different structure, and most of the time, strains breed true. Prion replication is nevertheless subject to occasional epimutation and then natural selection just like other forms of replication.[11]

When talking about denaturation you need to consider whether it's reversible or not. Cooking an egg changes the proteins so they can't go back to what they were, but freezing it doesn't.

The prions associated with these diseases may unfold during an autoclave process, and it may even destroy some of them, but it only takes one surviving protein to incite an infection in a host.

 

[PatrThom]

Fascinatingly scary, and the mechanism does sound very close to Ice-9's behavior.
The idea of "death by microorigami" is an interesting one.

I hope this is something that leaks over to the Folding@Home team. I'd like to see them try a few experiments with prion-related folding.

--Patrick

 

[strawman]

Maybe nanorigami. The prion associated with CJD is 150nM long. Here's a false color electron microscopic photo: