BC: MAD COW AND DEMENTIA
Found this from 2001 .. I'm sufficiently
concerned/curious to have myself tested
for 'prions' if such a test is available ..
As if mad cow disease isn't frightening enough, the cause is the stuff of science fiction. The cause is a mutant protein that kills the brain. It's called a prion and scientists haven't seen anything like it since Louis Pasteur found germs.
"I describe the prion as a completely new infectious particle. It's not a virus, not a bacterium, not a fungus. Different," said Dr. Stanley Prusiner.
Prusiner, of the University of California, San Francisco, won the Nobel prize in medicine for discovering the prion. It's a natural protein in mammals that can mysteriously deform itself, replicate and concentrate in the brain.
"The end result of this accumulation of prions in the brain are these big holes in the brain. A Swiss cheese appearance" in which the brain is wasting away, said Prusiner,
In the 1950s a disease similar to mad cow was found in Papua New Guinea. A tribe there got a brain-wasting disease called kuru after eating the prion-infected brains of dead relatives in a religious ritual. Cannibalism is the link. Mad cow, it seems, comes from healthy cows eating the remains of infected cows in feed. Somehow, the infectious prions jump to humans in beef.
The outbreak in Europe has launched a scientific race to find a blood test for prions. The idea is if you can find the infection in cows, you can prevent it in people.
"We can take all the animals that are positive, that are infected with prions, if your test is good enough, and we can keep all these animals out of the human food chain," said Prusiner.
Also working on a blood test is Dr. Robert Galo at the University of Maryland. Gallo, the same man who helped discover HIV, says there's nothing as indestructible as a prion. If it was in your meat, Gallo says, it could not be cooked out.
Gallo is unsure about the threat from mad cow. "We have to be concerned enough that we should be prepared, but I can't answer you that we should be scared," he said.
There are some reasons not to be alarmed by prion diseases. They are not thought to be contagious person-to-person, and despite the rising mad cow numbers in Europe, that disease is still very rare. However, of all the creatures found with a prion disease — cows, sheep, elk, human beings — not a single victim has ever recovered.
And here is the wild card. Remember that cannibal tribe? Some did not get sick for 40 years. To scientists, that means a small, but real, risk thousands of human carriers are incubating mad cow prions now, but don't know.
When asked if, in his darkest moment he thought that this is the plague of the 21st Century, Prusiner said, "I don't need a dark moment to wonder if that's the case, because everybody's wondering that, not just me."
Prusiner is certain someone will find a medicine to neutralize prions. Right now, mad cow is hard to detect, impossible to treat, and its true reach into human beings is unknown.
and some more .. urine test for prions ??
In a surprising and unexpected discovery, researchers in Israel have found a form of prion in urine that can indicate the presence of disease caused by the mysterious protein even before symptoms appear.
The findings suggest that a urine test could be developed to identify cows with mad cow disease, people with Creutzfeldt-Jakob disease (CJD), sheep with scrapie, and animals with other forms of prion diseases--transmissible spongiform encephalopathies, or TSEs.
The discovery is surprising because dozens of companies, academic research teams, and government groups have been in active competition to devise diagnostic tests for TSEs, but none had detected diagnostic prions or prion-related metabolites in urine before. Urine samples are relatively easy to obtain, whereas current TSE tests must be carried out on brain tissue samples obtained with great difficulty from postmortem autopsies.
The discovery was made by graduate student Gideon M. Shaked, senior lecturer Ruth Gabizon, and coworkers at the department of neurology of Hadassah University Hospital, Jerusalem [J. Biol. Chem., published June 21, Papers in Press, (http://www.jbc.org/cgi/reprint/C100278200v1.pdf)]. Gabizon is hardly a newcomer to prion research. A decade ago, she worked for neurology professor Stanley B. Prusiner of the University of California, San Francisco, who won the 1997 Nobel Prize in Physiology or Medicine for discovering that prions cause TSEs.
While looking for other substances in hamster urine, she and her coworkers found an isoform (tissue-specific form) of protease-resistant prion protein in the urine of prion-infected hamsters, and subsequently also in the urine of cattle and humans with prion diseases. Few researchers had looked for prions in urine before, Gabizon notes, because they generally believed prions would not pass through the kidneys in substantially intact form.
Using Western blotting (electrophoresis and immunological detection), the Hadassah group detected the prion isoform in hamster urine before disease symptoms appeared--a hopeful sign for diagnostic purposes. They found a prion isoform in CJD patients as well. And in a blind test they were able to distinguish cows with mad cow disease from those without it.
Steve Dealler, a consultant medical microbiologist at Burnley General Hospital, in the U.K., who follows TSE diagnostic developments closely, comments that the discovery of a diagnostic form of prions in urine "is bound to be an exciting twist, and this method ... may well turn out to be the final answer" to the problem of TSE diagnosis.
Research chemist Mary Jo Schmerr of USDA's National Animal Disease Center,, Ames, Iowa--who is developing an antibody-binding assay to detect low levels of prions in blood--says the new study "has potential." Despite "a few unanswered questions" in the study that still need to be addressed, she believes prion isoforms in urine "could very well prove to be a valid diagnostic marker for TSEs."
A potentially troubling implication of the study is "the alarming possibility that urine from prion-infected individuals, either ill or as yet incubating the disease, can somehow transmit prion diseases," Gabizon and coworkers note. "This prospect is especially disturbing in the case of [TSE-infected] cattle as well as in natural scrapie in sheep. Since the mechanism by which these diseases are transmitted among animals within the herd was never elucidated, it is conceivable that urine can contaminate the living areas of these animals" and thus spread the diseases to other members of herds.
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