DURHAM, N.C. -- It's already too late for the patient, but still the doctors come running.

"We've got it down now to where we can have the brain tissue out in about 20 to 25 minutes," says Dr. Allen Roses of Duke University. "And usually it's no longer than 30 to 45 from the moment death has been certified."

In the unique Rapid Autopsy Program at Duke University Medical Center, minutes are precious in the battle against Alzheimer's disease, the degenerative brain disorder that progressively robs its victims of memory, language, reasoning, dignity and self. It afflicts some 2 million Americans, killing 150,000 each year.

To learn the cause of Alzheimer's and ultimately find an effective treatment, many doctors now believe they must have human brain tissue almost immediately after death -- before the brain begins to change. Until now, separating the effects of the disease from the effects of death has been difficult.

So in 1985, Roses and other doctors at Duke began to offer Alzheimer's families an unusual opportunity: Help advance scientific understanding of the disease by agreeing in advance to donate the patient's brain at the moment of death.

Over the past two years, Duke doctors have performed 30 rapid autopsies on the bodies of Alzheimer's victims and other terminally ill patients who volunteered to be part of the research effort.

The brain tissue obtained is being used in a host of chemical and genetic studies, at Duke and around the world. The tissue already has provided new insights into a possible genetic cause of Alzheimer's, although scientists say it is premature to draw such a conclusion.

Says Dr. Andrew Monjan, acting director of neuroscience and neuropsychology at the National Institute on Aging: "The value of this tissue, I think, is that it more represents what happens in life than what happens in death in Alzheimer's." A Positive Step

There is no cure for Alzheimer's disease, and no effective treatment. Last week, federal health officials announced the start of widespread trials of a drug called THA, which seems to improve memory in some patients. It is, a researcher said, "the first drug" that offers "some measure of hope" for patients, but it is not and will never be a cure.

Much more needs to be learned, and for some people, such as Shirley Hamilton of Greensboro, N.C., allowing a family member to participate in research is a ray of hope in an otherwise hopeless disease.

Hamilton is interested in the rapid autopsy program for several reasons, not the least of which is her fear that one day she may become an Alzheimer's victim. She laughs uneasily, saying, "Now every time I forget something, I think Alzheimer's. It's awful."

For 17 years, she helplessly watched Alzheimer's take her mother, Sally Bernau. At 75, totally incapacitated and in a fetal position, Bernau died in a Durham nursing home on April 5, 1985.

She was the second person enrolled in the rapid autopsy program, one of the handful of initial cases done to demonstrate to the National Institutes of Health that rapid autopsies could and should be done.

The early cases were funded with a $250,000 grant from Greensboro philanthropist Joseph Bryan, whose wife was an Alzheimer's victim. The grant and the early autopsy cases were so compelling that NIH named Duke one of 10 national Alzheimer's research centers, awarding it a $4 million grant over five years.

Later, Bryan donated an additional $10 million to Duke to build a new medical research center for investigating Alzheimer's and other neurological disorders.

It was news of the first grant that caught Hamilton's attention and ultimately led to enrolling her mother, who "when she still had the ability" had signed a living will asking that heroic measures not be taken to sustain her life.

Escaping the traditional life-sustaining procedures of conventional medical and nursing care is one of the "big pluses of the rapid autopsy program," Hamilton says. "I'm afraid a lot of people would think very negatively about this, but it was such a loving, caring, dignified thing to do that I can't say enough about it."

"I remember afterward that Dr. Roses thanked us for our courage," Hamilton recalls, "but I didn't think it took any courage. It was something that made sense out of a disease that has none. It gave something positive out of a disease that has nothing positive except that there is no pain."

Tears trickling down her cheeks now, she adds, "Alzheimer's robs people of everything that makes them human, and everything that makes them who they are."

"In a bad situation," says Hamilton, "you look for something good, but this was something really good. It made the frustration of seeing someone die by degrees finally bearable."

For Hamilton's close friend, Janet Sheffield, also of Greensboro, the rapid autopsy experience even was "exciting, because I felt my Dad had actually died a long time ago. I'm sure he would have been pleased to be able to contribute this way to understanding the disease."

Her father, Richard Brooks, 80, died at Duke Medical Center last December and became the 20th rapid autopsy patient. It turned out that he did not have Alzheimer's, but rather a rare brain disorder that mimics it.

"This points up," Sheffield notes, "that the autopsy is the only definitive way of knowing that it's Alzheimer's disease."

"In fact, he had been diagnosed at Duke in 1983, and there was no question in anybody's mind -- the doctors' or my family's -- that it was Alzheimer's," she says.

"My mother feels so good about it," Sheffield says, "that she has signed up to be a control" -- agreeing to have an immediate autopsy of her normal brain after death for scientific comparison.

Those are typical family reactions, says Gail Cook, one of two nurse clinicians who enroll and work with the families.

"The tissue is so important and we feel so grateful to them," explains Cook, "but for the families, who have felt so helpless for so long, it's such a positive experience that we've been made to feel as though we've given them something."

Cook says families typically see the opportunity as a way to fight back, "a chance finally to do something." 'We Needed a New Way'

Doctors have long suspected that in the hours or days between death and a regular autopsy, important changes were occurring in the brain. Enzymes and other brain proteins, particularly the messenger RNA code, deteriorate very rapidly after death {see box}.

"The time it takes you to ask for the autopsy precludes doing it rapidly," Roses explains. "We needed a new way, we needed to do everything beforehand, arrange it before death, and still make everybody comfortable with it. We had to be sensitive to ethical and moral problems."

What they have come up with is a program that requires family approval at every step of the way.

Usually, several meetings are held with family members to explain the program and to determine if the required unanimity among principal family members can be obtained.

Once a patient is enrolled, doctors at Duke keep in regular close contact with the caregivers -- family or nursing home. When death appears imminent, the patient is transported by ambulance to Duke Medical Center. Special hospice-like rooms are reserved for rapid autopsy patients.

From then on, "terminal surveillance" begins so that doctors and researchers can be alerted the instant death is official. The family's care wishes are followed, but Roses says, "By this time it's a no-code situation and we give oxygen, primarily to preserve the brain tissue, and water through a squeegee bottle."

Because the law does not permit autopsy consent prior to death, a responsible family member carries a radio beeper 24 hours a day for consent confirmation once death is certified.

"They have been told repeatedly that they can change their mind at any time," says Cook, "but no one has."

Even as the family member is being told of the death, notification is under way of the pathology team on call as well as the researchers on call from each of several laboratories involved in experiments with the brain tissue. Members of the team come from various laboratories that are investigating genes, brain chemicals, enzymes and growth factors.

Portions of the fresh brain tissues are rushed immediately to some of these laboratories for biochemical experiments. But most are instantly frozen in liquid nitrogen to about minus 112 degrees Fahrenheit, and are "banked" at about minus 200 degrees for future study.

"About two dozen things happen all at once, and they're all interrelated," says Duke neurobiologist John Gilbert. "Each team member gets their small slices as prearranged, and usually you fix them there.

"I label each sample -- what it is and where it came from, who the patient was, was he AD (Alzheimer's) or normal (control). It's pretty fast-paced."

But, says Cook, "we really don't think, 'well, this is just another specimen.' It takes a great deal of preparation, of talking to families quite extensively."

After the death, autopsy results are explained to family members, who are encouraged to remain in touch with research developments. "It's very touching because usually death is such a private affair," Cook says. "You can't help but build some bonds that you don't break when they leave."

The Program's Future

Although it has had inquiries from other states, because of the logistics the program can only handle Alzheimer's patients within a 250-mile radius of Durham.

Roses is continuing to seek more funding to provide other research teams with the brain tissue, but a $250,000 grant proposal for that purpose was turned down by the National Institutes of Health earlier this year.

"People don't realize how devastating Alzheimer's is," he says. "It's a much more staggering disease than AIDS -- not to minimize that problem -- but just in terms of impact and economics.

"We're spending about $60 million a year for nursing home care -- not all for Alzheimer's, but a big chunk is for people afflicted with brain disorders. By comparison, we're spending about $20 million on the research," he says. "I think it's staggeringly underfunded, criminally underfunded."

While researchers have speculated that Alzheimer's could be caused by aluminum poisoning or some virus, "now genetics is the hottest thing," says Roses. And he believes the rapid autopsies will be a key to providing the answer.

"In the next 10 years, we have the potential to know who will develop Alzheimer's -- and to think about stopping it."

Lawrence Spohn is a free-lance writer based in Kernersville, N.C.