New Research

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Creighton Researcher Studies Prions,

Possible Cause Of Mad Cow Disease

OMAHA, Neb. -- Proteins that may cause " mad cow "

disease, chronic

wasting disease in mule deer and elk, and Creutzfeldt

Jakob disease in

humans, all of which are fatal neurological diseases,

are the subject of two

studies at Creighton funded by federal grants.

Bessen, assistant professor of medical

microbiology and immunology,

has received a five-year $488,000 National Institutes

of Health grant and a

three-year $250,000 grant from the United States

Department of Agriculture

to study prions.

Prions are proteins that all humans possess in their

normal form. The disease

forms are chemically identical but are configured in

different shapes.

" What makes prions unique is that these infectious

agents do not appear to

contain a nucleic acid molecule which is the genetic

basis of all life forms, "

Bessen said. " Prion diseases are caused by the

misfolding of normal prion

proteins. There is debate about how this misfolding

occurs and how that

pattern is replicated. "

It appears that " mad cow " disease, or bovine

spongiform encephalopathy

(BSE), adapted from sheep scrapie.

" If you eat processed foods, such as sausage or

products with animal-derived

food additives, you may have been exposed to sheep

scrapie, with no effect, "

Bessen said. " However, cattle apparently are

susceptible upon oral exposure

to scrapie-contaminated feed additives. Once they

infected cattle, the prions

may have adapted further to create an agent that

posed danger to humans.

" The BSE epidemic in the United Kingdom indicates

that these agents,

transmissible spongiform encephalopathies or TSEs,

can adapt unpredictably

to new hosts and potentially can cause widespread

neurodegenerative

disease, " Bessen said. " There have been more than

175,000 cases of BSE in

Europe, mainly in the United Kingdom. "

Initially, the potential danger of BSE to humans was

downplayed, but BSE

now has been linked to 27 cases of variant

Creutzfeldt-Jakob disease in

humans. The cattle industry has changed feeding and

herd management

approaches to avoid possible transmission of prion

disease to humans and

animals. No cases of BSE have been confirmed in the

United States.

Bessen is examining the molecular basis of prion

strain diversity and how

prions replicate. He also will investigate the

ability of drugs to inhibit the

conversion of normal prions into the disease forms.

Creighton is an independent Catholic university

operated by the Jesuits. It

recently was ranked No. 1 for the third consecutive

year among Midwestern

universities in the U.S. News and World Report

magazine's 1999 " America's

Best Colleges " edition.

Creighton enrolls approximately 6,200 students in the

Colleges of Arts and

Sciences and Business Administration, the Graduate

School, University

College and schools of Nursing, Medicine, Law,

Pharmacy and Allied Health

Professions, Dentistry, and Summer Sessions.

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