Aldehyde-Stabilized Cryopreservation Procedure Wins Brain Preservation Prize • Hacker News Board

Re: Aldehyde-Stabilized Cryopreservation Procedure Wins Brain Preservation Prize

#31

Post by lsparrish » Thu, Feb 11, 2016, 2:12 AM UTC

kanzure wrote: post #26

lsparrish wrote: post #21

Earlier quoted context omitted.

His criticism bad (as ever), since he assumes all information needed for nervous system function is the same as all information needed to replicate a given nervous system. Most of the information needed for function in any system is generic across similar systems. We are only interested in the information that is specific to the individual.

> We are only interested in the information that is specific to the individual. Not necessarily; there's a lot of value to be had in the non-specific information, too.

This technique is useful for general neuroscience purposes, yes. My point was just that it isn't what is critical to preserve for the sake of cryonics.

Re: Aldehyde-Stabilized Cryopreservation Procedure Wins Brain Preservation Prize

#32

Post by lsparrish » Thu, Feb 11, 2016, 2:27 AM UTC

dnautics wrote: post #18

Aldehydes covalently bond and crosslink the proteins and irreversibly kill all of the fixed cells. There is zero hope that this provides a solution to cryopreservation except in the slice it up and look at it under the microscope sense.

> Aldehydes covalently bond and crosslink the proteins and irreversibly kill all of the fixed cells.

That is the textbook answer, however these bonds are only "irreversible" as a matter of biochemistry. You can actually break any chemical bond by increasing the temperature enough. The problem for our purposes is that this means destroying the structure.

> There is zero hope that this provides a solution to cryopreservation except in the slice it up and look at it under the microscope sense.

The trick to reversing the bond without damaging the structure would be in delivering high enough amounts of energy with high enough precision to have only the intended effects. This may or may not be physically possible. However, to rule out the possibility completely, we would need to consider a wide variety of physical interactions that are well outside the range of biology and wet-solvent chemistry, in addition to the full spectra of potential biomimetic and biological approaches.

Re: Aldehyde-Stabilized Cryopreservation Procedure Wins Brain Preservation Prize

#33

Post by dnautics » Fri, Feb 12, 2016, 2:05 AM UTC

lsparrish wrote: post #32

dnautics wrote: post #18

Aldehydes covalently bond and crosslink the proteins and irreversibly kill all of the fixed cells. There is zero hope that this provides a solution to cryopreservation except in the slice it up and look at it under the microscope sense.

> Aldehydes covalently bond and crosslink the proteins and irreversibly kill all of the fixed cells. That is the textbook answer, however these bonds are only "irreversible" as a matter of biochemistry. You can actually break any chemical bond by increasing the temperature enough. The problem for our purposes is that this means destroying the structure. > There is zero hope that this provides a solution to cryopreser…

Good luck. When you make an imine with an aldehyde the principal mechanism of irreversability is that a stray reductant (available in spades in biochemical settings) takes the imine down to a primary amine. (This is not found in most textbooks, you just have to know that). Now, a primary amine is a relatively stable covalent bond, and getting selective deamination is going to be especially difficult since there's plenty of amines around. Not the least of which is the other side of the lysine that the aldehyde attached to in the first place.

Re: Aldehyde-Stabilized Cryopreservation Procedure Wins Brain Preservation Prize

#34

Post by xlm1717 » Fri, Feb 12, 2016, 7:59 PM UTC

Houshalter wrote: post #28

jacquesm wrote: post #12

Earlier quoted context omitted.

What a load of bull. Cryopreservationist walks into a bar. Goes 'Hey, everybody, pay me $50 and I'll show you a fantastic trick, I take your watch, put it in a bag, smash it up with a hammer, then open the bag and out comes your watch'. Fascinated a number of patrons sign up and pay their $50, hand over their watches. Audible gulps as the watches go into a nice silver velvety bag and a very large hammer smashes down…

This analogy makes little sense. Nature is the man with the hammer. After you die he smashes your brain to bits. There is nothing left. You cease to exist forever. Cryopreservation is an attempt to stop the man with the hammer. By preserving your brain, you give yourself a chance that you can be revived, if technology advances that far. Which certainly seems very likely. It is a tragedy that the majority of people wh…

Dying is already expensive enough without cryopreservation.

Re: Aldehyde-Stabilized Cryopreservation Procedure Wins Brain Preservation Prize

#35

Post by cryonaut » Sun, Feb 14, 2016, 11:04 AM UTC

zimpenfish wrote: post #19

PZ Myers had a good take on this a few days ago - http://scienceblogs.com/pharyngula/2016/01/29/how-can-you-pr... > What I didn’t do with my experiments in aldehyde-preserved brains was claim that I was preserving all the information necessary for nervous system function. I was quite aware that I was chemically nuking all the proteins in the tissue; I was washing out most of the chemistry; I was destroying most of th…

PZ made the usual error that most biologists make: if it's busted, the information isn't there and can't be recovered. It's dead. The vital spark has departed. It's soul has gone to heaven. Vitalism is alive and well.

Ask anyone who owns a computer if you can recover information from the hard drive of a busted computer.