Life on ice: extreme cold is both a killer and lifesaver. Learn how scientists are tapping its powers to preserve body organs--and corpses. (Life Science: temperature scale * cryogenics).
His body was whisked away to the Arizona desert: There, inside the Alcor Life Extension Foundation in Scottsdale, Williams' corpse was plunged into a stainless-steel vat of liquid nitrogen, a chemical element so frigid it chilled his body to -195[degrees]C (-319[degrees]F). Why on Earth? you may wonder. The slugger's fervent hope was that one day medical science would be able to "reanimate" his body--in other words, bring him back to life.
The process is called cryonics Derived from the Greek word for "cold," cryonics has drawn widespread interest since 1967, when a 73-year-old psychology professor who died of cancer became the first human ever put into deep freeze. Alcor, one of several U.S. cryonics organizations, says that of 100 or so people cryogenically frozen since then, 49 lie in its tanks. Another 580 people are signed up.
Think cryonics sounds like pure Hollywood? Many scientists think so, too. "Ted Williams is not coming back," insists Kenneth Storey, a biologist at Carleton University in Ottawa, Canada. Storey is a leader in cryobiology, the science of how extreme cold impacts plants and animals. And while reanimating entire bodies may be a stretch, Storey and others are striving to find methods to freeze and thaw pieces of individual cells, scraps of tissue, even organs like livers and hearts--because for transplant patients freezable organs could be lifesavers.
During surgery, even when kept in a cooler, the human heart lives merely eight hours outside the body; surgeons must race against the clock to deliver the organ to its new owner. And each day in the U.S., 13 people die waiting. If scientists figure out how to freeze organs, they could preserve them for weeks or months instead of hours.
But freezing organs has proven impossible because ice can shred body tissue. So Storey and other scientists have turned to nature for solutions.
In Earth's coldest places, certain plants, insects, and other animals somehow survive. Take the tiny wood frog (Rana sylvatica), for example. During winters in northern Canada, where temperatures plunge to -29[degrees]C (-20[degrees]F), the small brown creatures cuddle on the forest floor beneath a thick blanket of leaf litter and snow--frozen solid. Pick one up and you'd swear it was dead.
And it is--sort of.
In his laboratory, Ken Storey has found that frozen "frogsicles" have no heartbeat, brain activity, or breath. "They're no more alive than a pot roast," Storey says of the specimens he stores in Tupperware in the lab fridge, often not far from somebody's lunch. But let the wood frog thaw a few hours, and soon it leaps about and croaks. The big mystery--Storey has spent 20 years trying to unravel it--is how do these frogs do it?
Normally, ice is deadly to living tissue. If a human finger or toe is exposed to freezing temperatures for too long, the tissue loses blood, turns black, and dies. The condition, called frostbite, occurs because all living organisms contain water--an adult human is made up of as much as 70 percent.
As water nears the freezing point of 0[degrees]C (32[degrees]F), its molecules expand and become less dense, which explains why ice cubes float. But just as expanding ice beneath a road can cause the road to crack, ice forming in tissue can rip apart cells and blood vessels. "Cells become squashed between ice crystals and are killed," says Brian Wowk, a physicist at 21st Century Medicine in California, who's devising strategies to chill and preserve organs for transplant.
So how do the frogs beat the chill? Storey and his team discovered that to survive their icy environments, wood frogs and other freeze-proof animals boast some unusual tricks. The winter flounder, a fish that swims in glacial polar seas, manufactures a special chemical compound or protein known as an "ice blocker." The protein sticks to tiny ice crystals that form in the fish's body and prevents more water molecules from latching on--the thorny crystals never get big enough to damage the fish.
The wood frog uses a slightly different strategy. As soon as the frog's skin begins to freeze, the animal's liver, an organ that filters toxins from the body, cranks out a type of blood sugar called glucose, also found in humans. Glucose may act like a natural antifreeze to lower the freezing point of water. Storey found the wood frog's body cells absorb so much glucose that water inside the cells never totally freezes. So while a wood frog may look and feel frozen stiff, no more than 65 percent of its body water actually turns to ice--and its cells remain syrupy inside.
The next step, says Storey: to determine how to use biological antifreezes on human organs in order to freeze and thaw them without destroying their delicate cells.
BACK TO THE FUTURE
Cryonics organizations such as Alcor carefully monitor developments in cryobiology. Cold can kill living tissue--but as the wood frogs show, cold can also preserve it. That's because as living things grow cold over time, chemical reactions that power cells grind to a halt. "If you stop chemistry, you essentially stop time in a living thing. That's the secret of cryopreserration," says Wowk.
But many cryobiologists think freezing entire bodies is scientifically impossible, and--in the words of Ken Storey--"insane." Why is he so skeptical? Research on freeze-proof animals already suggests different cells and tissues require different kinds of biological antifreeze. "The same chemicals that protect a liver won't protect a heart," Storey says.
Still, a small number of scientists who believe in the future of cryonics are plowing ahead anyway. "What proof do we have that medical technology in a future era won't be able to restore dead bodies?" says Ralph Merkle. "Suppose you lived in the year 1700 and developed a life-threatening illness, and the doctor said he couldn't cure you. Wouldn't you like a second opinion from a modern-day doctor with modern-day tools?"
Merkle, a scientist at the Texas cryonics company Zyvex, is attempting to construct machines and other devices one molecule--even one atom--at a time. The science is called nanotechnology, and Merkle argues it could help bring cryonically frozen bodies back to life. He and others envision a day when microscopic robots will repair cells damaged by freezing or illness (see illustrazion, p. 10). "Disease is simply atoms arranged in the wrong way," says Merkle, who's also an advisor to Alcor.
Merkle himself is so convinced, he's signed up with Alcor to have his head frozen after he dies--known in cryonics circles as a "neuro." But immortality doesn't come cheap. Alcor charges $120,000 to put an entire body in deep freeze, while a brain costs $50,000. And even Merkle agrees that success is a long way off. Nanotechnologists have barely reached the stage where they can manipulate individual atoms--let alone build tiny robots capable of rearranging the atoms in a single cell.
"We're just beginning," he says.
THINK ABOUT IT: Should researchers be able to perfect cryonics to bring corpses back to life? Why or why not?
HOW HOT? HOW COLD?
These are the three most common scales used to measures temperature. All use the freezing and boiling points of water as reference tempertures.
([degrees]C) Degree Celsius
A widely used metric system scale that has 100 divisions between the freezing and boiling points of water.
([degrees]F) Degree Fahrenheit
The U.S. is the only nation to use this scale for official weather observations. It includes 180 divisions between the freezing and boiling points of water.
Use by scientist, this scale measures down to the lowest temperature, or absolute zero (OK). One Kelvin equals 1[degrees]C.
CRYONICS: 5 Steps to Deep Freeze a Corpse
More than 100 corpses, including baseball legend Ted Williams, have been "cryogenically frozen," or placed in deep-freeze storage. Like a freezer preserving food, the procedure draws heat from the body. As the body chills, molecules within tissue cease motion and halt decay.
1 Day 1: Clinical death
Body is packed on ice and transported to a cryonics facility. Ice slows tissue decay.
2 Day 2: Body fluids drained
A five-step procedure replaces body fluids with a solution that helps prevent tissue damage caused by freezing.
3 Days 3 to 7: Dry ice treatment
Body is placed on dry ice, frozen carbon dioxide gas with a temperature of -78,5[degrees]C (-109.3[degrees]F). The body is slowly cooled to -40[degrees]C (-40[degrees]F).
4 Days 8 to 14: Liquid nitrogen treatment
Body is slowly submerged in a container of liquid nitrogen, a chemical element with a freezing point so low it boils at -196[degrees]C (-320[degrees]F).
5 Day 15: Long-term storage
Once the body hardens, it's transferred to a liquid nitrogen-filled cryostat, a container made of insulating materials like fiberglass and the mineral perlite, The body is maintained at -196[degrees]C (-320[degrees]F).
COLD AS ICE
The temperature at which liquid turns solid is called the freezing point. Water, for example, freezes at 0[degrees]C (32[degrees]F). But not all liquids have the same freezing point. Experiment to see which of the following liquids has the lowest freezing point: milk, water, rubbing alcohol, or vinegar.
Which liquid do you expect to freeze first? Why? At what temperature do you expect your liquid to freeze?
(one set per group) 1 ruler * 1 tall narrow glass * 1 plastic bowl or container 2 to 3 times wider than the glass * 1 thermometer * ice * salt * timer
1. Divide into four groups.
2. Assign a different liquid to each group. Group A tests milk, Group B water, Group C rubbing alcohol, and Group D vinegar.
3. Measure the size of the glass, mark the halfway point, and pour the liquid up to the mark.
4. Carefully place the liquid-filled glass inside the plastic container.
5. Insert the thermometer vertically in liquid. Record the starting temperature.
6. Fill the plastic container with ice and sprinkle 1/4 cup of salt over the ice. (Be careful not to get salt in liquid.)
7. Place the plastic container in the freezer. Begin timing.
8. Check the experiment at 5-minute intervals and remove glass container at the first signs of freezing. (Ice crystals should form on the liquid's surface.)
9. Record the liquid's temperature and the total amount of time it took to freeze.
Compare results. Which liquid has the highest freezing point? The lowest? How would your results change if you added salt to the liquid?
Did You Know?
* Absolute zero, or -273.15[degrees]C (-459.67[degrees]F), is the lowest possible temperature. It's defined by the absence of all heat energy--a state in which molecules in matter cease to move.
* Physicists at 21st Century Medicine in California chilled a rabbit kidney to -21.7[degrees]C (-7[degrees]F) for one hour. When thawed, they successfully transplanted it into another rabbit. With current technology, freezing the kidney for periods longer than one hour creates tissue damage.
* Injuries like cuts and bruises cause tissue to inflame or expand. This puts pressure on nerve fibers, creating pain. Cold packs work to decrease swelling and pain by constricting tissue, blood vessels, muscles, tendons, and ligaments.
Language Arts: Imagine it's the year 2500, and you've just been revived from a 400-year cryogenic slumber. Write a short science-fiction story about your new life.
Would you want your body to be frozen and brought back to life? Why or why not?
CHECK FOR UNDERSTANDING
Directions: Answer the following in complete sentences.
1. Which chemical do cryonics organizations use to freeze corpses, and how does it work?
2. Define cryobiology.
3. What is frostbite? Describe how and why it occurs.
4. Why might studying wood frogs and winter flounder help scientists preserve human organs?
1. Cryonics organizations use liquid nitrogen to preserve corpses because it has a freezing point so low it boils at -196[degrees]C (-320[degrees]F).
2. Cryobiology is the science of how extreme cold impacts plants and animals.
3. When a human body part is exposed to freezing temperatures for too long, the tissue loses blood, turns black, and dies. It happens because the human body is composed of as a much as 70 percent water. As water nears freezing point, molecules expand. And as ice crystals form in tissue, they can rip apart cells and blood vessels,
4. Animals like wood frogs and the winter flounder can survive in freezing cold temperatures. By studying these species, scientists may find ways to freeze and thaw human organs without damage. This could help increase the supply of organs available for transplant surgery.
"Putting Mortality on Ice," by Henry Fountain and Anne Eisenberg, The New York Times, July 14, 2002
To learn more about cryonics, log on to the Alcor Life Extension Foundation Web site: www.alcor.org
Chemistry, by Antony C. Wilbraham, Dennis D. Staley, Michael S. Matta, and Edward L. Waterman, Prentice Hall, 2002, Chapter 3
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|Date:||Jan 10, 2003|
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