 |
 |
Scientists Make Madcow Prion in Lab for First Time Fri 30 July, 2004 04:36 WASHINGTON (Reuters) - Researchers have for the first time made a prion in the laboratory and used it to demonstrate that the misfolded proteins are indeed the sole cause of mad cow disease, the U.S. and German scientists reported Thursday. The research, published in the journal Science, also may help open the way to treatments for the currently untreatable and incurable family of prion diseases, which include not only mad cow but the human Creutzfeldt Jakob disease, and a related human form of CJD caused by eating mad cow-infected beef. "Our study demonstrates that misfolding a particular segment of the normal prion protein is sufficient to transform the protein into infectious prions," said lead researcher Giuseppe Legname at the University of California San Francisco. Scientists from the Heinrich-Heine Universitat in Duesseldorf, Germany also took part in the study. The researchers created a synthetic prion by using bacteria to grow prion fragments and then folding them into larger protein structures. They injected these into the brains of mice bred to be susceptible to transmissible spongiform encephalopathies such as bovine spongiform encephalopathy -- mad cow disease -- CJD and others. The mice started showing symptoms in about a year, the researchers reported. "A great deal of evidence indicates that prions are composed only of protein, but this is the first time that this has been directly shown in mammals," Legname said. "The challenge in the last few years has been to figure out exactly how to demonstrate that prions are made entirely of protein." There had been some argument that so-called prion diseases were in fact caused by virus-like particles, or perhaps another kind of infection. Prions are protein particles that naturally exist in the body. But they become misfolded in the TSE diseases and the misfolded prions are themselves infectious, or so the argument goes. "For the first time, we can create prions in the test tube, which will change the way scientists do experiments in the field," said Legname's UCSF colleague Stanley Prusiner, who won a Nobel prize in 1997 for his discovery of prions. "We now have a tool for exploring the mechanism by which a protein can spontaneously fold into a shape that causes disease." Prusiner said in a statement he hoped the findings would open ways to study other brain-destroying diseases such as Parkinson's and Alzheimer's. SOURCE: Reuters, UK http://tinyurl.com/6m947 * * * ---------------------------------------------------------------------- To sign-off Parkinsn send a message to: mailto:[log in to unmask] In the body of the message put: signoff parkinsn