Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: WEDNESDAY, September 1, 1993 TAG: 9309010034
SECTION: NATIONAL/INTERNATIONAL PAGE: A-1 EDITION: METRO
SOURCE: Associated Press
DATELINE: WASHINGTON LENGTH: Medium
The test could save a great deal of money, shield patients from having to undergo extensive testing, and help doctors quickly distinguish those with a fatal disease from those with treatable forms of impairment, said Dr. Daniel L. Alkon, a researcher at the National Institute of Neurological Disorders and Stroke.
"If this test fulfills its promise, it should have an immediate positive impact on our health care delivery system because we can save hundreds of millions of dollars in diagnostic evaluations," he said.
The test is based on the discovery that brain cells in Alzheimer's disease patients develop a flaw that closes up a microscopic pore, or channel, through which flows a form of potassium.
Alkon said researchers speculated that if this happens in brain cells, why not other cells in the body? With that in mind, the NIH team tested cells taken from tissues in the nose and from the skin. In both cases, he said, the test showed that the potassium channels were collapsed in tissue from Alzheimer's patients.
Alkon's team then treated cells with chemicals that cause microscopic sparks in healthy cells. Where the potassium channels were closed, in the Alzheimer's cells, there were no sparks.
JoAnn McConnell, senior vice president for medical and scientific affairs of the Alzheimer's Association, said that if the validity of the diagnostic test can be proven it would be important in dealing with the disease, but she warned that other promising tests for Alzheimer's have been disappointing.
"We are guardedly optimistic about this," she said. "There have been a number of tests for biological markers which have been proven to not be true.
"It would be very beneficial to doctors to determine exactly what the disease entity is because there are many forms of dementia that are treatable," said McConnell. "If you could rule out Alzheimer's then you could explore seriously the other possibilities."
Alzheimer's disease is a progressive disorder that gradually destroys memory, the ability to function, and, eventually, life itself. There now is no treatment. An estimated 2.5 million to 4 million Americans have the disease, and McConnell said the number is expected to triple within 20 years.
Alzheimer's disease can be diagnosed with certainty only after an autopsy.
Alkon said the Alzheimer's tests were conducted on 50 cell samples, including some from patients with other forms of dementia. He said the researchers were able to correctly determine which specimens were from Alzheimer's patients and which came from patients without the disease.
He said a much larger experiment will use enough patients to statistically verify the skin test. It also will help determine if the test can detect the disease at a stage before the symptoms of memory loss develop, he said.
by CNB