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Nerve-Regrowth Studies Buoy the Paralyzed

August 12, 1986|PETER BAKER

Bob Yant thought it could never happen to him.

Living on Balboa Peninsula so close to the Wedge, he had heard the ambulance sirens each time yet another surfer cracked his back or neck and ended up paralyzed for life. He knew the risks as he sauntered down to the beach every day that summer of 1981, but, like most of us, he didn't think about them.

Then the "meat wagon" came for him.

Diving into a breaking wave, Yant struck his head on a sand bar. Instantly paralyzed from the shoulders down, he was catapulted overnight from the idyllic life of a healthy, 30-year-old surfer to a world where showering and shaving is a two-hour chore and brushing his teeth is an accomplishment. Like hundreds of thousands before him, Yant heard a doctor utter those awful words: "You'll never walk again."

"When they first told me I was going to be a quad, oh, man, I cried," Yant recalled, sitting in his comfortable one-story Balboa home, describing the events with a detachment born of spending five years in a wheelchair.

But he is hardly detached about discoveries made in spinal cord research that might--just might--enable him to walk again.

'Wisdom' Falling Away

When Yant, founder and president of the American Paralysis Assn.'s Orange County chapter, became a quadriplegic five years ago, the world still accepted the old medical "wisdom" that central nerve tissue could not regenerate, that a paralysis like Yant's was incurable.

Now researchers have proved that nerve cells will regrow under the right circumstances, and indeed, that a cure for spinal injuries may not be many years away.

Some recent developments:

- At UC San Francisco last month, researchers began testing in humans a drug they think will, if injected shortly after spinal cord injury, actually prevent paralysis in many cases.

- At UC Irvine and San Diego, scientists are working on regenerating damaged central nerve tissue in rats--a process called axon sprouting--by using certain hormones or by transplanting healthy tissue from aborted rat fetuses or from other areas of the animals' bodies.

- At Yale University last fall, two scientists severed the spinal cords of sea lampreys, eel-like creatures with nerve cells similar to those of humans, and only a few months later, some of them were swimming again. This was the first evidence of spinal cord regeneration in a vertebrate; now, using a special dye technique, the researchers hope to unlock the lampreys' secret.

- In other labs across the country, doctors and scientists are collecting clues about what makes the central nervous system work in the first place.

The central nervous system operates like the telephone network of a big corporation. The brain decides what muscles will do and "phones" its various "offices" with its orders.

The thin, gelatinous spinal cord--about the width of a little finger--is the telephone cable, carrying electric impulses from the brain to nerves that control muscles throughout the body. Break the connection and the brain has no way to control its various parts. The result is paralysis.

Most injuries to the spinal cord are relatively minor bruise-like abrasions. But unlike most other body cells, central nerve tissue does not regenerate by itself, and even a small injury can cause paraplegia (loss of sensation below the waist) or quadriplegia (below the shoulders or neck).

In 1906, Santiago Ramon y Cajal, a leading neurologist, won a Nobel Prize in part for determining that central nerve tissue could not be regenerated--a thesis taken as gospel until very recently.

Before World War II and antibiotics, there wasn't much need to challenge the assumption, since infections killed most spinal cord victims. Today, however, about 500,000 Americans suffer from some form of paralysis. Each year, there are as many as 15,000 new victims--average age 19. That's a new victim every 30 minutes.

One hope lies with Dr. Carl Cotman, a researcher at UC Irvine and a past winner of the MacArthur Foundation "genius" grant.

Dogma Turned Around

"It was said just three years ago that a nerve fiber in the central nervous system wouldn't regenerate. Period. That was dogma," Cotman says. "But that's clearly now been turned around. You can make a nerve fiber regenerate."

Cotman is concentrating on two areas:

- Transplanting nerve tissue from rat fetuses into the damaged area of a rat's spinal cord and watching to see if the regrown axons (the long tentacles that carry electric impulses from one nerve cell to another) will rewire the circuitry.

- Exploring natural chemicals in the body--called growth factors--to find out how they affect the natural healing process.

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