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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, author notes, because they generally believed prions would not pass through the kidneys in substantially intact form.
Using Western blotting (electrophoresis and immunological detection), the 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. 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," author et al 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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