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 Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=17031