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January 2004
A Way to Prevent Vision Loss in Premature Infants
Weakening Hearts Get Some Help
Liver Function: Two New Threats
Radiation Oncologist Ted DeWeese
A Way to Prevent Vision Loss in Premature Infants
A new study by specialists at Hopkins and 25 other centers in the U.S. for the first time gives eye doctors a precise way to identify premature babies at highest risk of abnormal blood vessel growth in the retina and subsequent blindness. The computerized tool should lead to treatment of retinopathy of prematurity (ROP) at its earliest stages. The researchers showed that early treatment significantly reduced the likelihood of poor vision from 19.5 to 14.5 percent at about one year of age. Early treatment also reduced the likelihood of structural damage to the eye from 15.6 to 9.1 percent.
Weakening Hearts Get Some Help
A steady pace from an electronic pacemaker could fight congestive heart failure say Hopkins researchers who studied outcomes from more than 1,600 patients with moderate to severe heart failure. Some patients received specialized pacemakers, while others were treated only with drugs. In the first three to six months after surgery, lead author David Bradley, M.D., found the specialized pacemakers can reduce heart failure mortality by 51 percent. As a patient's condition changes, Bradley says the pacemaker can also be easily adjusted with a wand that is placed on the skin over the pacemaker. The pacemaker is then adjusted using a laptop computer and without the need for further surgery.
Liver Function: Two New Threats
Although many older adults are doing what they can to reduce their risk of getting cancer and heart disease, chronic liver disease is rarely viewed with the same degree of concern. Yet the liver is a vital organ: It is necessary for regulating most of the substances carried in the blood and for breaking down many of the medications and harmful substances that enter the body. Liver failure, which can occur suddenly or gradually, may lead to severe bleeding abnormalities, brain dysfunction, and-in extreme cases-even coma and death.
Long-term excessive alcohol consumption and the hepatitis C virus (spread mainly through intravenous drug use) are two widely known causes of chronic liver disease. However, it has recently become clear that liver health is seriously threatened by two other significant, often ignored problems: excessive use of the popular pain reliever acetaminophen (Tylenol and others) and nonalcoholic fatty liver disease (NAFLD), which is closely associated with diabetes and obesity. The good news is that liver function can be protected by preventing or treating these and other threats.
Radiation Oncologist Ted DeWeese
Radiation oncologists don't use drugs or surgery, and they don't take images simply to diagnose disease. Instead, they treat cancer with the powerful energy of radiation. Known for his work on urologic malignancies, Dr. Ted DeWeese, Director of Radiation Oncology at Hopkins, devised the first adenoviral gene therapy trial for prostate cancer, using a common cold virus as a "smart bomb" targeting only cancer cells while leaving normal cells alone.
What's the current state of radiation oncology?
There have been staggering changes in the last five years that have affected the field in ways we only dreamed of before. Using molecular-based imaging, we'll be able to see tumors like never before -- not only what's in the organ we're interested in, but also cells related to the tumor outside the organ. Also, we'll be able to see the function of the tumor and direct therapies specifically toward it. When radiation is given one way, for example, tumors respond far differently than if it's given another way.
What are the different ways tumors respond?
For example, if a tumor depends on a specific protein to repair its DNA, then we might be able to deliver radiation to those tumors in a way that avoids activating this DNA repair system. Likewise, there are certain drugs that target these DNA repair pathways that can be designed to seek out only the cancer cell and, when combined with radiation, destroy cells at a greater rate. We've designed several ways to get the drugs into those pathways, one of the most interesting being through common cold viruses called adenoviruses. By injecting the virus into the tumor we're irradiating, we've shown both in the culture dish and in animals growing tumors that this combination will kill seven times more cells with the same dose of radiation than with radiation alone. We're about to start a clinical trial based on this work.
We're now using a very sophisticated, computer-driven technique called IMRT (intensity modulated radiation therapy) that precisely shapes the radiation beam to the exact shape of the organ. We also use the gamma knife and our other radiosurgery techniques to treat tumors to within an accuracy of less than one millimeter. It takes both real capital and human capital to pull it all off, but there's no doubt we can deliver radiation at higher doses with fewer side effects.
And the risks?
There's a double-edged sword to all that precision. If you're right on target, precision is good, and if you're off a little bit, you might miss part of the tumor. We go to great lengths to use three-dimensional imaging to specifically localize the tumor. While important, that's one snapshot in time, and an organ like the prostate can move within the body. So we've also adopted some new 3-D ultrasound techniques to see the tumor every day before the patient is treated, and determine if the tumor has moved slightly on that particular day. An even more precise way to see a cancer is to use a CT scan every day. I'd like to see us move toward using a CT scanner and a radiation machine in the same unit, so all could decide if adjustments are required that very day and then use the same machine to treat the patient right away. That allows us to be as precise as we could ever be.
How expensive is that for patients?
Interestingly, from the patient's perspective, it won't be more expensive than what we presently do. It's certainly more technically challenging, so the costs to Hopkins are slightly higher, because it's not yet known how to best integrate this into a standard clinical setting. But that's our job, to be at the cutting edge. That's why we have research physicists, Ph.D. and master's-level physicists who work with our physicians and biologists to understand the technology and apply it in the most reasonable fashion. I want us to evolve in ways that can improve our patients' lives. Because ultimately that's the goal. The rest of it is kind of an interesting dance.
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