Research machines probe nature for
medical, technological insights
Scientists from the Illinois Institute of Technology and the University of North Carolina used the APS for a major advance in radiography that could dramatically improve mammography and other medical and materials imaging.
The researchers developed a new imaging method that produces images never seen before in X-ray radiography.
Mammography presents very difficult imaging problems because of the density of the tissues which often hide tumors, says team member Dr. Etta Pisano, chief of mammography, Department of Radiology, University of North Carolina. With our method, we have produced images showing improved detail of cancerous tumors in human breast tissue. The detail is outstanding.
In conventional mammography, differences in tissue densities and composition are shown as contrasting areas in the image, allowing visualization of tumors or changes in tissue. However, differences between healthy and cancerous tissues are very small, and scattering of X-rays can lead to blurring and even lower contrast, making it difficult to detect small tumors.
The new method uses a single-energy fan beam of X-rays instead of the broad-energy beam used in conventional imaging. The object is scanned through the beam, reducing scatter and helping to visualize low-contrast areas that otherwise would be lost.
The improved method could be used in a laboratory setting within five years, and in clinical applications in 10 years, the researchers say.
In a finding that is expected to lead to the development of a new class of drugs for allergy and asthma sufferers, researchers at Northwestern University and Harvard Medical School have used the APS to determine the precise shape of the receptor molecule that triggers the allergic response in the human immune system.
The finding is the first structure reported for a member of this family of antibody receptor proteins. It was made by probing crystals of the receptor called the high-affinity immunoglobulin-E (IG-E) receptor with the extremely brilliant X-rays from the APS.
We think this identifies the structure that all of the members of this antibody receptor family will have, says Theodore S. Jardetzky, the Northwestern X-ray crystallographer who led the study.
The IG-E receptor was of particular interest because an estimated 20 percent of the population suffers from allergies. Asthma afflicts 15 million people in the United States and causes 500,000 hospitalizations and 5,000 deaths each year.
Current medical treatments are aimed at blocking the action of the signal molecules or the inflammation they cause. But knocking out the master switch would in principle be more effective than trying to impede all the signals sent out by the mast cell which releases histamine and the anticoagulant heparin. The cell, Jardetzky says, would never release those compounds because it would never know a triggering allergen was present.
Several pharmaceutical and academic teams had been trying to study the receptor by expressing its gene in cultured cells. But the receptor protein that researchers obtained from these cells had stubbornly defied all attempts to solve its molecular structure until the light from the APS revealed the secrets.