1.   But they are found in every cell of the body, as are the mutated proteins in patients with the diseases.

2.   Prions are the mutated proteins responsible for the outbreak of the disease in the United Kingdom that led to panic and a ban on exports of British beef.

3.   These mutated genes are put into bacteria to make the mutated proteins, which are then tested to see how well they perform a given task.

4.   Why the mutated proteins selectively kill only certain brain cells remains a mystery.

5.   Gene-assist drugs would circumvent this, not by curing the genetic defect but by helping the mutated protein work more normally.

6.   Mad cow disease is believed to be caused by a mutated protein that is transmitted through eating pieces of the brain or nervous system of an infected animal.

7.   Mad cow disease, which is the result of a mutated protein, gradually eats away at the brain.

8.   The process prevents the transmission to humans of bovine diseases, including mad cow disease, which is caused by a mutated protein, he said.