American scientist wins Nobel Prize for medicine
His work provides insight into brain diseases
October 6, 1997
Web posted at: 8:51 a.m. EDT (1251 GMT)
STOCKHOLM, Sweden (CNN) -- An American biologist won the 1997 Nobel prize for medicine Monday for his discovery of a new class of germ believed responsible for brain-wasting conditions such as "mad cow" disease.
Stanley B. Prusiner, a professor at the University of California at San Francisco, discovered prions, "an entirely new genre of disease-causing agents," the Nobel citation from Sweden's Karolinska Institute said. "Prusiner has added prions to the list of well-known infectious agents, including bacteria, viruses, fungi and parasites."
Prusiner began his search for prions in 1972, after one of his patients died from dementia resulting from Creutzfeldt-Jakob disease, the human equivalent of "mad cow" disease.
After 10 years, he and his team produced a preparation derived from diseased hamsters' brains that contained a single agent he called a prion.
His work was greeted with skepticism at first: Unlike known infectious agents, prions contain no genetic material, and are simply proteins. Furthermore, the gene encoding for prions is found in all mammals, including humans.
However, his work has since been linked with understanding Bovine Spongiform Encephalopathy -- also known as "mad cow disease" -- Alzheimer's disease, and other dementia-related illnesses.
Prusiner's work found that, under normal conditions, prions are innocuous, but that they have an innate ability to convert into harmful structures. Prusiner found that "prion diseases may be inherited, laterally transmitted, or occur spontaneously," the institute said, and the immune system cannot defend the infected person against them.
Inherited prion diseases account for 10 to 15 percent of CJD cases, as well as two very rare conditions, fatal familial insomnia and Gertsmann-Straussler-Scheinker disease.
But the vast majority of CJD cases occur spontaneously. Last year, the British government announced that cattle with mad cow disease were the most likely cause of a variant of Creutzfeldt-Jakob disease in humans. The cattle were believed to have eaten contaminated sheep offal.
Prusiner's research to define the nature of the prion he discovered is hoped to create a basis for drug development and new types of medical treatment strategies.
His prize, worth $1 million, will be awarded on December 10 along with the economics, physics, literature, chemistry and peace prizes. The date marks the anniversary of the death of Alfred Nobel, whose will established the prizes.
The doctor's past honors include a Potamkin award in 1991 for his research into Alzheimer's disease.
Reuters contributed to this report.