[ExI] Subject: [New_Cryonet] Fw: [cryo] Fwd: Steve Van Sickle's presentation a
m2darwin at aol.com
m2darwin at aol.com
Sat Sep 7 05:12:51 UTC 2013
-----Original Message-----
From: Alejandro Dubrovsky
Sent: Friday, September 6, 2013 9:53 AM
To: cryo at postbiota.org
Subject: [cryo] Fwd: [ExI] Steve Van Sickle's presentation at SENS6
-------- Original Message --------
Subject: [ExI] Steve Van Sickle's presentation at SENS6
Date: Fri, 6 Sep 2013 01:40:34 -0400
From: Rafal Smigrodzki <rafal.smigrodzki at gmail.com>
Reply-To: rafal at smigrodzki.org, ExI chat list
<extropy-chat at lists.extropy.org>
To: ExI chat list <extropy-chat at lists.extropy.org>
Yesterday I had the pleasure of attending Steve Van Sickle's
presentation at SENS6, reporting his results with cryonic preservation
of kidneys. Steve developed a technique for persufflation of organs
perfused with cryoprotectants using cold helium. He was able to cool
pig kidneys to liquid nitrogen temperature, achieving total
vitrification while *avoiding* fractures! I was absolutely floored by
his work, easily the most important presentation at SENS6 so far.
Steve also described calculations for hyperbaric persufflation, which
might allow vitrifying a human body in *a few minutes*!
There's only one small problem (at least for me) with this "remarkable
breakthrough", or more particularly, with the crediting of it.
When Steve Van Sickle was President of Alcor, and Tanya Jones was in
charge of acute patient care, I engaged in an extended and frustrating series of
emails with Van Sickle, copied to Tanya and to Alcor Director Dr. Brian
Wowk. The subject of this correspondence was my urging Alcor to switch to
using gas perfusion following cryoprotective perfusion of patients, in order
to achieve both more uniform cooling, as well as much faster cooling and
very possibly the reduction or elimination of fracturing injury in patients.
The reasons I suggested this were not merely theoretical. When I was
working as a researcher for Manrise Corporation (Fred and Linda Chamberlain) in
the mid-1970s I had conducted gas perfusion experiments on rabbit kidneys
and heads following the work of Schimmel, et al. with gas perfusion of rat
kidneys; http://www.ncbi.nlm.nih.gov/pubmed/5872343 , that of of Hamilton
and Lehr with gas peerfusion of canine small bowel
http://www.ncbi.nlm.nih.gov/pubmed/4702169 and of the work of Guttmann, et al., using hedlium
perfusion in canine kidneys: http://www.ncbi.nlm.nih.gov/pubmed/1259562 and
http://jama.jamanetwork.com/article.aspx?articleid=661256 .
This work demonstrated that uniform cooling rates on the order of 2-3 deg
C min were achievable and, as I noted in my correspondence with van Sickle
at that time, there was no evidence of fracturing, even in kidneys loaded
with 25% w/v cryoprotectant.
I would also point out my extensive discussion of the idea of gas
perfusion in cryonics in this post on Cryonet during the "cooling fluids debate"
that took place there on 12/17/92:
http://www.cryonet.org/cgi-bin/dsp.cgi?msg=1465
I pointed out that this technique was far easier to implement than was
perflurochemical (PFC) perfusion and that it had the advantage of having
already been proven out from a practical standpoint not only by my work in the
mid-1970s, but by work done by Pegg, et al., in the in 1978;
http://www.sciencedirect.com/science/article/pii/001122407890086X . What's more,
experiments conducted in recent years using oxygen persufflation of hypothermically
(non-frozen) stored organs had demonstrated that putative problems with gas
emboli, or endothelial cell dehydration, were, in fact NOT problems and
that organs perfused with gas could be transplanted with the long term
support and survival of the animals being a uniform outcome:
1: Srinivasan PK, Yagi S, Doorschodt B, Nagai K, Afify M, Uemoto S, Tolba
R.
Impact of venous systemic oxygen persufflation supplemented with nitric
oxide gas
on cold-stored, warm ischemia-damaged experimental liver grafts. Liver
Transpl.
2012 Feb;18(2):219-25. doi: 10.1002/lt.22442. PubMed PMID: 21987402.
2: Minor T, Akbar S, Tolba R, Dombrowski F. Cold preservation of fatty
liver
grafts: prevention of functional and ultrastructural impairments by venous
oxygen
persufflation. J Hepatol. 2000 Jan;32(1):105-11. PubMed PMID: 10673074.
3: Stegemann J, Hirner A, Rauen U, Minor T. Gaseous oxygen persufflation
or
oxygenated machine perfusion with Custodiol-N for long-term preservation of
ischemic rat livers? Cryobiology. 2009 Feb;58(1):45-51. doi:
10.1016/j.cryobiol.2008.10.127. Epub 2008 Oct 17. PubMed PMID: 18977213.
4: Minor T, Olschewski P, Tolba RH, Akbar S, Kocálková M, Dombrowski F.
Liver
preservation with HTK: salutary effect of hypothermic aerobiosis by either
gaseous oxygen or machine perfusion. Clin Transplant. 2002
Jun;16(3):206-11.
PubMed PMID: 12010145.
5: Lauschke H, Olschewski P, Tolba R, Schulz S, Minor T. Oxygenated
machine
perfusion mitigates surface antigen expression and improves preservation of
predamaged donor livers. Cryobiology. 2003 Feb;46(1):53-60. PubMed PMID:
12623028.
6: Gong J, Lao XJ, Zhang SJ, Chen S. Protective effects of L-arginine
against
ischemia-reperfusion injury in non-heart beating rat liver graft.
Hepatobiliary
Pancreat Dis Int. 2008 Oct;7(5):481-4. PubMed PMID: 18842493.
7: Nagai K, Yagi S, Afify M, Bleilevens C, Uemoto S, Tolba RH. Impact of
venous-systemic oxygen persufflation with nitric oxide gas on steatotic
grafts
after partial orthotopic liver transplantation in rats. Transplantation.
2013 Jan
15;95(1):78-84. doi: 10.1097/TP.0b013e318277e2d1. PubMed PMID: 23263502.
8: Minor T, Isselhard W, Klauke H. Reduction in nonparenchymal cell injury
and
vascular endothelial dysfunction after cold preservation of the liver by
gaseous
oxygen. Transpl Int. 1996;9 Suppl 1:S425-8. PubMed PMID: 8959878.
9: Saad S, Minor T, Nagelschmidt M, Fu ZX, Kötting I, Paul A, Troidl H,
Isselhard
W. [Revitalizing donor livers after cardiovascular arrest with venous
oxygen
persufflation]. Langenbecks Arch Chir Suppl Kongressbd. 1998;115(Suppl
I):705-8.
German. PubMed PMID: 14518345.
10: Tolba RH, Schildberg FA, Schnurr C, Glatzel U, Decker D, Minor T.
Reduced
liver apoptosis after venous systemic oxygen persufflation in
non-heart-beating
donors. J Invest Surg. 2006 Jul-Aug;19(4):219-27. PubMed PMID: 16835136.
11: Sun HW, Shen F, Zhou YM. Influence of perfusion by gaseous oxygen
persufflation on rat donor liver. Hepatobiliary Pancreat Dis Int. 2006
May;5(2):195-8. PubMed PMID: 16698574.
Van Sickle's response was, essentially, to argue that gas perfusion simply
could not compete with the exchange capability of a liquid - even a liquid
with relatively poor heat carrying capacity, such as a perflurochemical
(PFC), or a mixture of PFCs. These remarks were presumably made on the basis
of a patent by Brian Wowk and demonstrating the utility of PFC for
improving heat exchange during cooling of organs and whole animals.
My efforts to point out to Steve that this technique was severely limited
because:
* Because of the increasing viscosity, and ultimately the solidification
of the PFCs at temperatures right around the critical glass transition point
for M-22, the ability to remove heat from the patient is lost at precisely
the point during cooling when it was most needed.
* Perfusion of PFCs was incredibly uneven in the tissues due to a short
circuiting effect that occurred when very low viscosity PFC first opened a
channel of flow between the arterial and venous circulations. These "first
opened" channels effectively "stole" much of the flow from the capillary
beds.
* The PFC proved virtually impossible to remove, proved obstructive to
subsequent perfusion and precluded any access to the circulation at storage
temperatures.
* PFC perfusion was logistically very difficult and there were many
problems with cryoprotective perfusate continuing to stream out of the animals'
circulatory systems requiring extensive filtration and multiple trap
placement in the PFC perfusion circuit (on both the venous and the arterial
side).
Perfusion circuit of a dog undergoing subzero PFC perfusion cooling to ~
-70 deg C in 1995:
Prototype PFC perfusion cooling and re-warming machine developed at 21CM
circa 1996:
And lastly, that pumping PFC through Silastic (silicone rubber) tubing caus
ed the build-up of dangerous electrostatic charges which, on two
occasions, resulted in fires in the operating room and the destruction of the costly
centrifugal pumps being used to pump the PFC. One fire had to be
extinguished with a CO2 fire extinguished and it caused nearly $2,500 worth of
damage - not to mention ruining the experiment! These problems were never
definitively solved...
Still, I could not get through to Van Sickle and I did not receive any
response from Tanya Jones regarding this matter.
Shortly after Peter Thiel funded Van Sickle and Jones' Argo Biomedical in
February, 2012, I received an email (anonymous) informing me that the
technology Argos was developing was being kept "top secret" in large measure to
avoid a response from me, like this one. I was informed that the basis for
Argos' research venture was the communications from me to Van Sickle and
Jones in the mid-2000s. This prompted me to place a call to Dr. Greg Fahy
and to ask him if he knew what Argos' research platform was? His response was
that he had agreed to keep the matter confidential and that he intended to
honor that agreement.
The idea of using helium (or other) gas perfusion to increase both the
rate and the homogeneity of cooling in organs is not a new one and it did not
originate with me. While I can fairly take credit for being the first to
propose this for use in cryonics, and to be the first to actually apply the
technique to isolated heads, I have always been careful to credit the
researchers who originated and first validated the utility of this idea. To
those who would say that this idea is both obvious and compelling for
application in cryonics, I would point to the correspondence reproduced below,
wherein as recently as 2008, I am arguing for adoption of this approach - to no
avail.
Reaching the minimum concentration of cryoprotectants needed to achieve
vitrification (CNV) uniformly in human cryonics patients is very difficult
due to peri- and post-cardiac arrest ischemia. The result is that substantial
freezing occurs in areas of the brain that are not quite at CNV. The
obvious way to solve this problem is to eliminate ischemia. But, alas, this is
not now possible. However CNV is a function of not just the CPA
concentration, but also of the cooling rate. Currently, Alcor is limited to a cooling
rate of ~ -3 deg C per hour for brain and this means that the CNV must be
very high - well over 60% (v/v). If that cooling rate could be increased to
even 0.5 deg C/min, the CNV would be lower and more of the brain in
ischemic patients would thus likely undergone vitrification, as opposed to
freezing.
This is what I argued be done for Alcor patients many years ago. I
subsequently repeated this argument to people at CI in 2007-8 - again to no
avail.
In closing I would like to quote Isaac Newton in a letter to Robert Hooke
on 15 February 1676:
"If I have seen further it is by standing on ye sholders of Giants."
For the context of this quote see:
http://www.newtonproject.sussex.ac.uk/view/texts/normalized/OTHE00101
Generally, (but sadly, not always) it is in the character of innovators
and academics to generously acknowledge the intellectual lineage of their
work. Indeed, one of the reasons that Newton is, to this day, so much more
beloved and respected than Robert Hooke, is because he had both the wisdom and
the personal integrity to acknowledge that his efforts, Herculean though
they were, were possible only because he himself had stood upon the
shoulders of giants.
Mike Darwin
____________________________________
From: M2darwin
To: REDACTED
CC: wowk at 21CM.com, gfahy at 21CM.com, aschwin.de.wolf at gmail.com,
chana.de.wolf at gmail.com, m2darwin at googlemail.com
BCC: danila.medvedev at gmail.com
Sent: 10/4/2008 4:29:55 A.M. Pacific Daylight Time
Subj: Cold Gas Perfusion
Hello All,
After much effort I retrieved my 1970s photocopy of Pegg's paper wherein
he fails to reduplicate Guttman's work. The useful thing about this paper
and the Schimmel paper on ultra cold gas perfusion of dog and rat kidneys is
that they show what kind of cooling rates are possible and what the range
of gas flows through dog kidneys was in Pegg's hands (i.e., a credible,
solid researcher whose work is reproducible).
Schimmel http://www.ncbi.nlm.nih.gov/pubmed/5872343:
Pegg
I've attached both papers plus a bit of history from Greg circa 1978 when
he was very hot to trot for cold gas cooling . I've also extracted and
relabeled the cooling curve graph from the Pegg paper. The principal problem
with Pegg's paper is that the kidneys were in a cold air bath; in fact her
had to wrap them in a rubber glove to SLOW the rate of cooling of the cortex.
Schimmel et al., cooled their kidneys in an insulated container with the
only source of cooling being the intra-arterial helium they used.
Helium flow rates through dog kidneys were 750 ml/min = or - 140 ml/min
and cooling rate to -80 deg C using gas chilled to -90 deg C was 2.8 deg
C/min! This is in close agreement with Schimmel et al's data also copied below.
I've marked up the Pegg data showing very conservative estimates for
cooling and they come out where Pegg said they do: it is important to realize
that the OVERALL rate of cooling is probably much slower than would be the
case with a kidney or a patient loaded with a vitrifiable mixture because:
1) There is a huge 'loss' of efficiency in cooling rate in kidneys that
freeze because the latent heat of fusion must be dissipated. This is not a
problem in systems to be vitrified.
2) The delta decay is enormous in Pegg's study because he held his cold
gas temperature to no lower than around -80 deg C and kept his delta of gas
to organ at around -40 to -50 deg C for the first part of the procedure
(less later on). If the delta T were TWICE this from the start the cooling rate
would be a lot faster. In fact his peak rates were in the range of 4.5 deg
C min according to the text in his paper.
3) He used helium which as he notes is particularly bad at heat transfer.
To what extent this made up by better flow (he reports helium literally
pouring out of the uninjured surface of the kidney!!!!! is unknown. However,
if nitrogen is as much better you guys say, then cooling rates of ~3 deg
C/min should be easily achievable for the kidney and presumably for the brain
in patients without bad vascular obstruction.
If you eliminate the problem Pegg had with the superficial cortex cooling
faster than the deep cortex and medulla by insulating the patient/organ
from the cold bath gas then you would see a virtual abolition of any
significant difference between surface and core cooling - presumably eliminating
viscoeslastic injury.
4) Finally, unlike the case with PFCs the vasculature will be open so that
nanomachines or worst case, fixatives, can be introduced later at subzero
temperatures. It will also be far cheaper than using PFCs if N2 works OK.
Mike Darwin
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