- The Washington Times - Saturday, February 8, 2003

SYDNEY, Australia, Feb. 8 (UPI) — An Australian company said it has developed technology to remove the protein that causes mad cow and other neuro-degenerative diseases from blood samples.

The company, Gradipore, said its Gradiflow membrane technology can remove infectious prion proteins from two blood components — gamma globulin and albumin.

Scientists said the device could permit earlier diagnoses of animals afflicted with these diseases and enable farmers to isolate and remove infected animals from their herds. In addition, they said, it might be possible to use the membrane to detect the human forms of mad cow — known as Creutzfeldt-Jacob disease.

"This discovery is really important because if you pick up infectious prions at the earliest possible stage, while the animal is still alive, then you can limit the spread of associated diseases and start to look for a cure," Tim Wawn, Chief Operating Officer for Gradipore, told United Press International.

Wawn said the new technology is the result of experiments designed, performed and validated in collaboration with two institutions in Scotland: the National Blood Transfusion Service, an authority in the field of prion diagnostics, and Q-One Biotech, of Glasgow, an independent authority in the design and implementation of virus, prions and other contaminant validation studies.

Steven Mahler, associate professor in biotechnology at the University of New South Wales, also acknowledged the significance of the Gradiflow membrane.

"This discovery is novel and it has huge potential," he told UPI.

Prions are proteins that circulate in minute quantities in the blood. Although scientists are unsure how this occurs, when prions become diseased, they infect healthy prions and then congregate in big clumps in the brain, destroying healthy tissue.

This results in degenerative spongiform encephalopathy, or TSE, diseases, such as scrapie in sheep and goats, bovine spongiform encephalopathy (BSE or mad cow disease) in cattle, feline spongiform encephalopathy (FSE) in cats and Creutzfeldt-Jakob in humans.

All these diseases are transmissible and fatal.

Scrapie, which was first reported in Britain in 1730, has infected more than 1,000 flocks in the United States since its first detected case in 1947. Because of the fear of transmission, farmers often need to cull large numbers of animals, including healthy animals, to prevent infection.

The prions that cause these conditions occur in such small quantities in the blood that, until now, they have eluded detection in blood samples. The only reliable diagnostic tests for prion disease require extracting brain tissue, so they can only be performed post-mortem. Such testing is time-consuming and, due to lead times, can allow the disease to spread before the condition is discovered.

Wawn said although it has been known for some time that Gradiflow could detect viral and bacterial pathogens in the bloodstream, its ability to detect infectious prion proteins is new. The membrane unit can vary in size, depending on flow requirements, but the typical benchtop unit is about the size of a television set.

When a blood sample is introduced, the unit pulls the prions through a wafer-like membrane, either by electrical charge or by varying the size of the holes in the membrane.

Because all proteins have different sizes and electrical charges — and abnormal prions have a different size and charge from normal ones — the Gradiflow can even separate healthy prions from infected ones.

Once separated, the technology concentrates the prions in sufficient quantities for diagnostic analysis.

Because the Gradiflow can remove prions from the bloodstream, theoretically if someone with CJD were to donate blood, the infected prions could be removed and the blood sample freed from contamination.

Although researchers at the Australian Red Cross Blood Bank would not comment on the device, or on the possibility of its use in decontaminating the blood supply from other dangerous pathogens, industry insiders told UPI the organization thinks Gradiflow has a lot of merit.

Its most immediate potential benefit, however, is for the livestock industry.

"The technology means that if you have a herd, you can take blood samples from each of your animals and verify if any have diseased prions," Mahler said. "You don't have to kill them all just in case there is potential for infection. It takes the fear factor out of the decision-making process."


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