X-Message-Number: 17031
From: 
Date: Fri, 20 Jul 2001 02:53:13 EDT
Subject: Liquified brains

Mike Perry is correct in asserting that liquefaction of the human brain is a 
common postmortem change. The time course is dependent on many interacting 
factors a few of which I'll list:

*Premortem pathology (head injury, brain death, sepsis, fever, etc.)
*Medications (antibiotics, some therapeutic metal compounds such as 
cisplatin, arsenic, etc., slow this change)
*Postmortem conditions such as temperature, humidity, immersion in water...

I have observed countless autopsies, including quite a few done after 
exhumation. I remember being surprised at how often an otherwise well 
preserved appearing body would have brain liquefaction. The brain literally 
flows out as a viscous soup when the calvarium is pried loose from the top of 
the head.

I have been fortunate over the years to have contact with both fine 
pathologists and morticians, and have learned much from them. One of the 
first things I learned is that how well or poorly a brain is "fixed" by 
conventional embalming is very difficult to predict. In most cases the 
results are very poor because a minimal amount of embalming fluid is used on 
the head in order to avoid a bloated or overdistended look. This happens 
because most modern morticians have never really mastered an understanding of 
how to facilitate proper venous drainage and to approach embalming slowly 
with subphysiologic pressures until most of the gross blood has been cleared. 
They don't really need to do this since their aim is only temporary cosmetic 
preservation. Using 5 to 15 or even 25 p.s.i. is acceptable: the idea is to 
get some fixative containing fluid into at least the medium caliber blood 
vessels of the tissues so that it can diffuse out and fix the unperefused 
areas over several hours. It doesn't take much aldehyde to fix tissue long 
enough to get through a 3-day wake.

If the patient is embalmed very soon after death ~1 hour, has been on 
anticoagulents, or has exhausted or absent clotting capacity by bleeding out, 
liver disease, or the like, then it is possible the brain will be well 
embalmed. Otherwise most of the fluid follows the path of least resistance 
and perfuses the external carotids and thus the face and scalp. Morticians 
will sometimes try to get good brain perfusion by using a technique called, 
ironically, the "head freeze" wherein both carotids are cannulated and 
perfused at the same time under high pressure. This is done often for medical 
school cadavers or where long delays are anticipated between death and 
viewing.

Another technique when a long delay before burial is likely is to puncture 
the cribiform plates through each nostril and aspirate the brain out and down 
the drain. The largely empty cranial vault is then partially filled with 
cavity fluid or formalin gel and the nares packed with cotton and cosmetic 
wax. This is essentially the same technique that is routinely used on the 
abdomen; after arterial embalming is complete the mortician uses a long, 
sharp tool (trocar) to puncture all the visceral organs and aspirate fluids 
out of them. This includes the pleura (lungs) , the heart, the stomach, gall 
bladder and intestines, and the urinary bladder. Once the aspiration of these 
organ is completed, concentrated "cavity fluid" (usually 37% formaldehyde) is 
used to irrigate these body viscuses.

If a person is edematous at death the mortician may well use a high index (= 
more formalin and glutaraldehyde) fluid to try to draw off some water. 
Similarly, if the body is dehydrated and facial features are drawn and 
shrunken more fluid under greater pressure can be used to fill out the face 
(both of which may also result in better brain fixation).

Conversely, I've seen people exhumed after 4 or 5 years who had nice firm 
pink brains as rubbery as if they were fixed yesterday. I'm sure the light 
microscopic structure would have looked relatively good. BTW, the pink is 
from the carmine red or other coloring added to the embalming fluid to give 
the body a more lifelike look.

Finally, in early 1980's (as I recall) Jerry Leaf, Hugh Hixon and I examined 
rates of postmortem deterioration in dogs kept at ~23C for up to 48 hours. 
Results were variable but we were surprised to see in even very mushy brains 
that could only be fixed by immersion, that the large microscopic anatomical 
areas of the brain were clearly identifiable even at 48 hours. These brains 
were barely more than gray and quite malodorous sludge. It was interesting to 
see some slide fields teeming with neat, well defined rods which we realized 
were bacteria! The extensive EM and histological results of that work were 
presented at one of the Lake Tahoe Life Extension Festivals hosted by Fred 
and Linda Chamberlain many years ago.

There are a number of lessons to learn from the above:

1) Each case is unique. The first place to start is with the embalming record 
which should give the basics such as volume of fluid injected, pretreatments 
(usually bad things like capillary rinses containing detergents and bases), 
drainage, vessels used, and so on.

2) You can't be sure what you'll find till you exhume. I've only taken one 
such case in my 30 years in cryonics. I have no regrets We did a craniotomy 
on exhumation and the brain while unfixed and days postmortem was still pink, 
had intact red cells and showed good structure on light but not electron 
microscopy.

3) Soil temperature can be misleading in the winter. If the area is very cold 
with a deep frost layer and the grave is opened a day before the burial there 
will be (literally) nearly a ton of icy soil dropped onto the top of the 
vault. This can cool the body to ~5 C within 24 hours; especially if the 
funeral home is kept cold at night and the body is below room temperature 
when interred.

4) The body cavities will contain massively punctured and lacerated organs 
from trocaring and aspiration. If ever there was an argument for neuro, this 
is it. Also, the exterior of the body may well be covered in a gray mold 
which grows quite rapidly on some bodies; again this is common but variable.

It takes an extremely sophisticated family to make the many decisions 
required in such a horrendous case. Sadly, it was the law against cryonics in 
British Columbia which caused most of the delay the child I did experienced.

The best strategy when such cases are rarely taken is to examine the brain, 
take samples, cool to dry ice and then go over the data with the family and 
let them make the decision. First, of course, making sure they are both 
intellectually and emotionally equipped to make an informed decision.

The criteria for this last statement would fill a textbook.

Mike Darwin

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