Want an example of yet another orders of magnitude improvement in what bioscientists and biotechnologists can do? Blood tests will be able to detect diseases at much earlier stages when the FACTT assay reaches the market.
(Philadelphia, PA) - Researchers at the University of Pennsylvania School of Medicine have developed a paradigm-shifting method for detecting small amounts of proteins in the blood. Applications of this method will make discerning low-abundance molecules associated with cancers (such as breast cancer), Alzheimer's disease, prion diseases, and possibly psychiatric diseases relatively easy and more accurate compared with the current methodology, including the widely used ELISA (enzyme-linked immunoadsorbent assay).
ELISA is a common immune-system-based assay that uses enzymes linked to an antibody or antigen as a marker for picking out specific proteins. For example, it is used as a diagnostic test to determine exposure to infectious agents, such as HIV, by identifying antibodies present in a blood sample.
The sensitivity of detecting molecules by the new method, called FACTT, short for Florescent Amplification Catalyzed by T7-polymerase Technique, is five orders of magnitude (100,000 times) greater than that of ELISA, the Penn researchers found.
Senior author Mark I. Greene MD, PhD, the John Eckman Professor of Medical Science, Hongtao Zhang, PhD research specialist; Xin Cheng, PhD, research investigator, and Mark Richter, a research technician in Greene's lab, report their findings in the advanced online publication of Nature Medicine.
"The current ELISA tests can only detect proteins when they are in high abundance," says Zhang. "But the problem is that many of the functional proteins - those that have a role in determining your health - exist in very low amounts until diseases are apparent and cannot be detected or measured at early stages of medical pathology. It was important to develop a technique that can detect these rare molecules to detect abnormalities at an early stage."
One problem that'll arise as a result of more sensitive blood and saliva assays is finding very early stage cancers. Okay, you'll know you have cancer. But it is incredibly small and your body is big. How to find it? As things stand now in spite of advanced CAT scanners and MRI machines surgeons sometimes have to cut into people to poke around to find something oncologists can't localize even at an advanced state of illness.
Imagine a cancer about the size of a needle tip. You have lots of little cancers in your body that are stuck at a small size because they haven't mutated the ability to grow blood vessels (they do not yet secrete angiogenesis factors). How to find just the right cancer to remove that has just crossed that threshold? Seems hard to me.
|Share |||Randall Parker, 2006 March 14 10:41 PM Biotech Assay Tools|