Possible Cure For People with Creutzfeldt-Jakob Disease

University of California at San Francisco (UCSF) researchers have determined that two drugs currently approved to treat either malaria (quinacrine) or certain psychotic illnesses (chlorpromazine) are effective in treating mouse cells infected with an infectious protein known as a prion (PREE-on).

Prions are unlike any other disease-causing agent. All other pathogens -- bacteria, viruses, parasites, and fungi -- contain DNA and/or RNA. Prions do not contain DNA or RNA but are composed of amino acids, as are all proteins.

A prion causes a new variant of Creutzfeldt-Jakob disease, the human equivalent of "mad cow disease," as well as numerous other rare diseases in animals and humans. Prions destroy the brains of their hosts, causing it to look sort of like a sponge. Many of these diseases are very slow in causing damage in the brain.

Prion diseases are relentless and are always fatal. Fortunately, prion diseases have always been rare in humans. They have, however, provoked world attention in recent years as more than 105 teenagers and young adults in Europe are believed to have contracted the new variant of Creutzfeldt-Jakob disease (nvCJD) from eating beef from cattle infected with mad cow disease.

One in a million people each year develops a sporadic form of the condition, for which there is no known cause. Approximately 5-15% of all cases are inherited. Other infectious prion diseases include kuru, which arose among New Guinea natives engaged in ritualistic cannibalism, and CJD, which is caused by certain medical procedures (surgery with CJD contaminated instruments, injecting prion-contaminated cadaveric (cadaver=dead person) growth hormone and getting CJD contaminated dura mater grafts). Prion diseases also develop in sheep (scrapie), deer, elk and mink.

The prion is an infectious form of a normal protein, known as the cellular prion protein (PrPC), which exists in a healthy state in humans and many animals. The protein only becomes lethal when the slinky-like shape of a portion of the protein molecule loses its normal shape and is flattened into so-called beta-pleated sheets (fold a piece of paper several times and look at the end of it). Once this process occurs, the misformed prion protein latches on to the slinky-like portion of other prion proteins and untwists them into beta-pleated sheets.

The accumulation of the flattened beta sheets within prion proteins leads to structural damage in the nerve cells that ultimately causes cell degeneration. This degeneration is seen in the tell-tale spongy appearance of affected brain tissue - thus the alternative name for prion diseases: transmissible spongiform encephalopathies. While each prion strain contains a different protein conformation, each leads inevitably, if slowly, to

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