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“The wood frogs regularly undergo freeze-thaw cycles in the lab between 20 and a potentially infinite number of times,” says Dr. Kenneth Storey, a professor of biochemistry at Carleton University in Ottawa, Canada. “In nature they go through it about twenty times a year without harm. You can’t kill them with the normal temperatures; but if you froze it to the temperature of dry ice11 you’d kill it for sure.”
Can this process happen in humans? Storey, who also has the Canada Research Chair in Molecular Physiology, says, “No way. Frogs have a set of genes that we don’t have that allow them to undergo this process, and while it’s happening their bodies are producing huge amounts of cryoprotectant sugars. Normal levels are between about 4 and 8 mmol/L12 (70 to 150 mg/dL), and during the freezing process the frogs’ sugar level jumps to 400 mmol/L (7200 mg/dL). Humans go into a coma at 600 mg/dL. The human body can’t produce enough sugar to protect from cell and organ damage from the ice.”
I asked Dr. Storey how this might apply to zombies. “I’m afraid that’s not your answer. Freezing is fine for organs harvested for transplants. We use it to preserve sperm, eggs and embryos…but it won’t make a zombie or preserve a body that has become a zombie. Granted, in the lab we can introduce the gene from the frogs into a human cell and then freeze and thaw that successfully, but that’s a single cell. Try and duplicate that in a whole mammal and you destroy the mammal. Massive tissue destruction. In fact cold is used to destroy tissues, such as in the process of injecting frozen materials into tumors to destroy them, but that’s the reverse of a process that will reanimate a body. Can’t happen that way.”
That eliminates one possible theory, but it still leaves the question of hibernation. Could the infection cause the victim’s body to lapse into a hibernative coma so deep that it is virtually impossible (outside of a laboratory) to detect life? Ground squirrels appear dead when they’re in hibernation…why not humans?
“Understand the difference between hibernation in humans and that of some other animals such as the ground squirrel,” cautions Dr. Storey. “When a ground squirrel hibernates its metabolic rate drops from 100% to about 1%. When a human hibernates—say when a Swami goes into deep trance—the metabolic rate drops from 100% to only 99%. We’re a long, long way from inducing hibernation significantly deeper in humans.”
But the possibility still exists; and for our quest to find the scientific possibilities in the zombie this is an exciting lead. It’s a stretch, sure, but don’t forget that according to the physics of aerodynamics, a bumblebee cannot possibly fly. Science is exact, but it’s not yet complete.
This process of hibernation, both natural and induced, is being actively studied. At Seattle’s Fred Hutchinson Cancer Center scientists have been experimenting with hydrogen sulfide to temporarily convert lab animals from warm-blooded to cold-blooded, which is what happens during natural hibernation. It is not an unnatural process, and we know from our studies of all aspects of science that nature loves variation and mutation.
Hydrogen sulfide is a naturally occurring chemical in the body that buffers our metabolic flexibility. Among other things, this chemical regulates our body temperature at 98.6, regardless of whether you’re in Haiti or Nome. At the Hutchinson Cancer Research Center scientists have already induced hibernation in mice. The researchers hope, among other goals, to be able to induce hibernation in patients waiting for organ transplants. The process is known as metabolic hibernation.
Military science views this as one of several possible methods of preserving soldiers injured in the field until they can be transported to proper military facilities. Researchers see it as one possible way to induce hibernation for long-distance space travel. Doctors hope that it will be a lifesaver for patients with dangerously high fevers, and oncologists are looking to this as a way of temporarily eliminating oxygen dependence in healthy cells to make them less vulnerable targets to radiation and chemotherapy.
There are even some military experiments ongoing to determine if it would be possible to totally exsanguinate13 a wounded soldier, (see the box, “Weird Science: Fido of the Living Dead,” on p. 149). There is some supporting material on this in animal testing, though the issue of cellular damage from oxygen deprivation, especially to the brain, has not yet been solved. Even so, it does contribute another splinter of plausibility to the concept of a body that has received massive trauma, has suffered blood loss, and has had a severe metabolic drop still being technically alive.
The Zombie Factor
It’s even more plausible if zombies are the result of a disease that mutates the molecular physiology during the infection process and dramatically lowers the metabolism. Outside of practical science? Sure, just as induced metabolic hibernation is currently outside of practical science. Outside of possibility?
Not at all.
JUST THE FACTS
Raising Hell
What on earth would make the dead rise and attack the living? What sparks the reanimation process? What drives the hunger for human flesh, or in some cases, brains? What is the driving force behind this enduring and expanding mythology of zombies?
The simple answer is that there is no simple answer. There are almost as many theories as there are films and books in the genre, including radiation, plague, toxic spills, demonic possession, and even wrath of God. Granted, some of these theories are so absurd and unlikely that even the most die-hard zom fan (like me) have an impossible time suspending disbelief; while other theories are chillingly close to “possible,” according to modern science.
The zombie message boards and forums buzz constantly with discussions over which theory is the most valid; you hear it debated at genre conventions, book signings, or other events. So here are the leading theories on the cause of the zombie uprising, with some comments by a variety of experts.
Expert Witness
“The body is designed by evolution to have natural redundancies,” explains neurologist Dr. Peter Lukacs. “Without these redundancies we’d never survive injury or illness. For example you only really need about 10% function of the liver, and about 20% function of one kidney. If certain other functions were online, and the zombie possessed the ability to seal wounds, we would have as reasonable an understanding of how they work as science allows. And it’s not that far outside of science.”
To answer the question on which parts of the brain are required to make a zombie undead, it depends on how “human” the zombie is. Does the zombie have a pulse and/or breathes for example?
“A basic zombie’s functionability,” Dr. Lukacs explains, “is that it can walk and move its limbs. For this to happen, it would need the motor cortex—this is located bilaterally (both sides of the brain) near the top part of the brain and curves to the outer curvature of the brain—to be at least minimally functioning. The right motor cortex controls the left side of the body, and vice versa. The central part of the cortex moves the legs while the arms and mouth are located on the outer curvature. Actually, I would love to see a ‘stroke-like’ zombie shown in a film who has had a localized blow to one side of the head who drags one side of its body. Without a functioning motor cortex, a person is completely paralyzed.”
Considering the odd twitching and staggering of individual zombies in different films, it’s reasonable to assume that we have seen stroked-out zombies.
Dr. Lukacs adds, “Now consider the cerebellum, which is located near the base of the skull (lower part in back of the head). The basic function of the cerebellum is the coordination of movement. For example, in order to reach for an item, the arm muscles need to move smoothly so as not to under-or overshoot the item. If the cerebellum is damaged, the muscles work in a jerky fashion (causing ataxia). Without a functioning cerebellum, there is movement, but it is in a very jerky fashion (much like many zombies) though it makes it very difficult to walk but not impossible.”
So it would seem that a zombie needs to have at least a partially functioning brain. What else needs
to be in operation?
We know from zombie movies that they moan, which means they either breathe, however minimally, or they possess the ability to draw breath as needed in order to moan. My guess, supported by science and common sense, is that they do breathe. Not well to be sure, but moaning is created by air causing the vocal chords to vibrate. Let’s take that as read, then.”
We can also assume that zombies have a working circulatory system. Again, we’re talking minimal function, but we’ve seen zombies bleed in too many films to dismiss it as a possibility. Plus, science tells us in no uncertain terms that in the absence of blood and oxygen the brain will cease to function and will soon decay so that even if resuscitative steps are taken, the brain will be so much gray goop.
So, we can also take it as read that zombies do have some kind of circulatory system, however feeble. As we’ve already discussed, we’ve seen them bleed in plenty of movies, including Romero’s; so let’s attribute the inconsistencies relative to bloodless zombies as bad reportage…and may Romero forgive me.
If we want to stretch medical credulity (and let’s face it, we are talking about zombies here), we could consider the possibility that zombies have a hyperactive wound healing capacity. Not on the scale of Wolverine from the X-Men, who regenerates back to complete health, but more on the lines of car tires when they’re filled with a can of sealant. Wounds do seal, as we know, otherwise we’d bleed out from a paper cut. Proteins called fibrins and high-molecular-weight glycoprotein containing fibronectins bond together to form a plug that traps proteins and particles and prevents further blood loss; and this plug establishes a structural support to seal the wound until collagen is deposited. Then some “migratory cells” use this plug to stretch across the wound, during which platelets stick to this seal until it’s replaced with granulation tissue and then later with collagen.
So, if this process were stimulated by the same force that has reactivated the motor cortex (and other functions), and if it worked at a high-enough rev, then the zombie might be able to form seals around wounds to prevent total blood loss. If this process happened abnormally fast, then the zombie could even keep from bleeding out if shot, stabbed, or had a limb cut off. Mind you, this process would have to work at an incredibly accelerated rate, so the mutation would have to be elaborate and very complex.
And yet zombies can be killed. We know that from nearly all the stories: A bullet in the brain or severe cranial trauma seems to punch their ticket. I asked Dr. Lukacs to comment on this.
“For a zombie to breathe and have a beating heart,” Dr. Lukacs observes, “it will need to have a functioning medulla oblongata and pons. This is part of the brain stem and is located in front of the cerebellum. Destroying this alone would be difficult by trauma since it is in a relatively small area near the cerebellum. A forceful blow between the back of the head and the nape of the neck should damage the cerebellum and the brain stem; which could kill a person (but not necessarily a zombie) since it would damage the respiratory and cardiac centers of the brain stem. So the simple answer of what part of the brain to destroy to stop a zombie would be to destroy the motor cortex, located on the top of the head.”
So, not just any shot to the head?
“No way,” Lukacs assures us. “Zombie destruction would require a lot of accuracy. If I were to train soldiers on where to shoot a zombie in the head with a weapon that had a very localized effect (say doing damage in only the size of a quarter or nickel to a part of the brain or something like an arrow), I would advise them to shoot for the motor cortex region of the head: the top of the head, slightly below the ‘pointy’ part of the head. Another spot that would bring down a zombie would be to sever the spinal cord: all the connections from the brain go through the spinal cord to the lower body (arms, trunk, legs) so damaging that would paralyze everything below the part damaged. If the upper neck portion is damaged, the zombie would become a quadriplegic, versus the lower back causing a paraplegic zombie. Severing the spine will bring a zombie down but it will still have upper brain functions (if there is such a thing in zombies) meaning it can still bite people and move its head about (and have a beating heart and be able to breathe if it could before). So…though it requires more accuracy it’s still pretty much a headshot that will bring down a zombie and ‘kill’ it, while spinal damage will paralyze it but not kill it.”
“There are many reports of gun shot wounds to the head where the patient survived. The most impressive of these are some attempted suicides done with a firearm at point blank range. Though these cases were not fatal, the injury undoubtedly caused brain damage on some level. So, if a point blank head shot to a healthy human brain doesn’t ensure death, why should it in a zombie brain with fewer working brain tissue?”
The Zombie Factor
So, the headshot theory holds water, but it requires more refinement. But in later chapters we’ll also learn that a lot of other types of shots will do the trick, because killing a zombie may, at times, be far less important than merely stopping one.
JUST THE FACTS
Radioactive Zombies Ate My Brain
In Night of the Living Dead, it is suggested that radiation from a returning Venus space probe may have reactivated the central nervous system including (to a very limited degree) the brain. However, Romero never comes right out and says that this is the actual cause and instead drops hints through snatches of TV interviews and news stories.
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Art of the Dead—Scott Cramton
Ghouls
“28 Days Later turned the entire zombie genre on its ear. It was the end of the world, but it was brutal and fast. It was something that we really wouldn’t be able to fight and THAT was scary.”
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Can radiation raise the dead?
I put the question to Dr. Eric Gressen, Assistant Professor of Radiation Oncology at Jefferson Medical College.14 He answered, “Radiation therapy causes free radical formation that destroys DNA by slowing the repair of cancerous and normal tissue and upsetting the duplicating process. The more oxygenated the tissue the more free radicals and the more damage/irradiation effect. Dead brain tissue is lacking oxygen and hence radiation therapy will have little to no effect. Also, the more actively the tissue is growing, the quicker the effect, as the tissue regenerating process is faster and the damage to the DNA is more evident early on. Hence hair loss/skin changes are seen much sooner than in slow growing tissue that exists in the nervous system!
“Now if we give too high a dose when we irradiate the whole brain, what typically can happen is, over time, the myelin that coats the brain can break down, messing up our cross-circuitry, and we can get brain damage from as little as mild memory loss to overt dysfunction. Radiation therapy does not assist in the transmission process of information in the brain but actually ruins it by messing with the myelin and such The repair mechanisms for all DNA damage can be rather complex, but you can imagine that if we are dealing with dead tissue, the brain without oxygen is already decayed and irradiation is not going to liven things up. If anything, over time, the brain typically goes dead from lack of oxygen, hence the term brain dead from oxygen deprivation after heart attack, stroke, etc. Radiation therapy can also alter the blood vessels in the brain, assisting in stroke formation. None of the above regenerates the nervous system.
“Now I mention the chronic problems first because they are most significant to the patient. Acutely during the radiation treatment, you can get swelling of the brain. Since this is in an enclosed cranium, pressure in the brain can cause a whole array of symptoms, headaches, nausea, and vomiting, etc., which are typically controlled with steroids. Squeezing the brain is not likely to wake someone up. The nervous system is a late-responding tissue and hence any effect irradiation can have on this system is going to take months to years—not immediately—so ‘It’s alive, it’s alive’ will not occur.”
The Zombie Factor
The foregoing should, I think, effectively bury the concept of r
adiation from a returning space probe. To be fair to Mr. Romero, he never actually said that this was the cause of the dead returning to life. Talking heads on TV screens in the movie speculated as to whether it could be the reason.
JUST THE FACTS
Pathology of the Dead
Pathology (literally, “the study of disease”) is the diagnosis and study of diseases through examination of bodily fluids, cells, organs, and tissues. There are two primary fields within pathology: a medical specialty in which fluids and tissues are used to obtain useful information for clinical use, or forensics; and the study of the entire disease process.
Forensic pathology is that branch of science built around the need to determine the cause of death in criminal and civil law cases. Forensic pathologists are medical doctors whose specialty is usually anatomical pathology. Many of these are board certified by the American Board of Pathology. Forensic pathologists perform autopsies to determine cause of death. Sometimes this is going to be pretty simple (guy with a knife stuck in his heart), sometimes it’s complicated (guy with a knife in his heart who had taken lots of poison), and sometimes it goes into the realm of diseases, which includes infections.
Pathologists also examine wounds of all kinds, including bites. They examine tissue samples to determine the age of the wound, the presence of infectious agents, and a variety of other tests in order to create a clear picture of what caused the injury. And of course they look for the presence of drugs, toxins, chemicals, and poisons.
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Art of the Dead—Lisa Gressen
Got Brains?