November 16, 2012
NIH Podcast Episode #0172
Balintfy: Welcome to episode 172 of NIH Research Radio. NIH Research Radio bringing you news and information about the ongoing medical research at the National Institutes of Health – NIH . . . Turning Discovery Into Health®. I'm your host Joe Balintfy, and coming up in this episode, learning more about how a kind of chemotherapy drug works, better understanding on how the brain can adapt:
The question we were trying to answer is what happens to the hearing regions of the brain when a person is born deaf.
Also, tips for a healthy holiday season, and how the future of coronary artery disease may be diagnosed. But first, this news update. Here’s Craig Fritz.
Fritz: Adults with diabetes and multi-vessel coronary heart disease who underwent cardiac bypass surgery had better overall heart-related outcomes than those who underwent a stent procedure to improve blood flow to the heart muscle, according to the results from an NIH-funded study. The study compared the effectiveness of bypass surgery with the insertion of drug-coated stents. After five years, the bypass group had fewer adverse events and better survival rates than the stent group. Scientists say these study results confirm that bypass surgery is a better overall treatment option for individuals with diabetes and multi-vessel coronary disease and may assist physician’s efforts to prevent cardiovascular events such as heart attack and death.
For this NIH news update – I’m Craig Fritz.
Balintfy: News updates are compiled from information at www.nih.gov/news. Coming up how the brains of deaf people have adapted, tips to manage eating and stress during the holidays, a new way to see into blood vessels, and a new understanding of a chemotherapy drug. That’s next on NIH Research Radio.
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NIH study uncovers new mechanism of action for class of chemotherapy drugs
Balintfy: Researchers have uncovered new details on how a class of chemotherapy drugs works. In recent years, these chemotherapy drugs called PARP inhibitors have been shown to be promising anticancer agents for breast and ovarian cancer.
Pommier: PARP inhibitors have been found to be very promising for patients who suffer from predisposition because of BRCA, breast cancer-associated gene mutations.
Balintfy: Dr. Yves Pommier is with the NIH’s National Cancer Institute.
Pommier: So there’s a great interest because these patients their tumors was not responsive usually to most therapies and they turn out to be selectively sensitive to these PARP inhibitors. So that’s the big interest and there are many drugs in the pipeline today.
Balintfy: PARP, short for poly (ADP-ribose) polymerase, is a protein involved in cell growth. Blocking PARP enzyme activity prevents the repair of DNA damage and ultimately causes cell death.
Pommier: So if you block the poly (ADP-ribose) polymerase, the PARP, then it’s much harder for the DNA to be repaired.
Balintfy: Now researchers have discovered a significant new way in which these chemotherapy drugs work. They have also identified differences in the toxic capabilities of some of them. Dr. Pommier explains that these drugs were supposed to just choke the PARP enzyme.
Pommier: In fact, what we found is that some of the drugs do more than that. They poison the enzyme as the enzyme is attaching to the DNA itself and what we revealed is that some of the drugs do these better than others and they poison PARP.
Balintfy: And that he says is what kills the cancer cells. These findings suggest that there may be two classes of PARP inhibitors, ones that mainly inhibit PARP enzyme activity, and others that are dual inhibitors that both block PARP enzyme activity and also trap PARP.
Pommier: PARP inhibitors have to be looked at in this context because their activity is highly dependent on that particular function of trapping PARP on DNA.
Balintfy: Dr. Pommier expects these findings will offer new opportunities to target weaknesses in cancer cells. For more on this study and new cancer research, visit www.cancer.gov.
NIH study shows the deaf brain processes touch differently
Balintfy: People who are born deaf process the sense of touch differently than people who are born with normal hearing; this is according to NIH-funded research. Wally Akinso reports what researchers are learning about the auditory cortex, the part of the brain that processes sounds.
Akinso: A recent study suggests that since the auditory cortex of profoundly deaf people is not exposed to sound stimuli, it adapts and takes on additional sensory processing tasks.
Karns: In any scientific study we’re asking a specific question, and the question we were trying to answer is what happens to the hearing regions of the brain when a person is born deaf.
Akinso: Dr. Christina Karns is a NIH postdoctoral research associate in the Brain Development Lab at the University of Oregon.
Karns: The reason that we want to know the answer to this question is it tell us something about how the brain develops. We know that the basic instruction for how a brain is built based on genes, but carrying out these instructions is highly influenced by experience that tells the development is plastic—meaning flexible and multiple opposed to sort of hard and brittle. And because the experience of someone who’s born deaf is really different than the typical experience that can tell us how flexible is the brain development of the auditory system.
Akinso: Deaf people may process vision using many different brain regions, especially auditory areas, including the primary auditory cortex. However, no one has tackled whether vision and touch together are processed differently in deaf people, primarily because in experimental settings, it's more difficult to produce the kind of precise tactile stimuli needed to answer this question. Dr. Karns and her colleagues developed an apparatus that could be worn like head-phones while subjects were in a MRI scanner.
Karns: So we scanned the brain of hearing people and people born profoundly deaf while they did a task in the MRI scanner. We compared the brain signal measures between these two groups. While the people were in the scanner they do a task, where they detect dim lights or feel gentle touches to the face. So we had to develop this kind of crazy headphone apparatus that they can wear inside this kind of tight tube. And the tubes deliver both ear puffs and then they have a little fiber optic cable that presents a dim light so that we can present touch and vision right at the same time, right in about the same place. Our volunteers ended up looking a bit like a cyborg wearing this headset with all these tubes kind of attached aiming at their face but it was pretty comfortable for them.
Akinso: The researchers have been able to show that deaf people use the auditory cortex to process touch stimuli and visual stimuli to a much greater degree than occurs in hearing people.
Karns: And what we found was that in deaf participants Heschl's gyrus, which is primary auditory cortex, had a much stronger response to touch and vision than in the hearing participants. So in hearing participants just like you might expect that part of the brain is specialized for hearing. So it’s not going to be as responsive to these other senses. But in the deaf people the brain has reorganized or organized in a way that’s not typical so that they're responding to these other senses. And in fact the response to touch was about twice as strong as for vision. And touch and vision seem to interact with each other more in the deaf participants.
Akinso: The study adds to a growing list of discoveries that confirm the impact of experiences and outside influences in molding the developing brain.
Karns: One of the really cool findings was that in some deaf participants the way that touch and vision in auditory cortex interacted was so strong that a single flash of light appeared to be two flashes when it was paired with two air puffs. So feeling two touches made them think they saw two lights. And what was really cool was that those deaf participants with the largest response in the primary auditory cortex saw this illusion more often than others.
Akinso: Dr. Karns says there are several ways the finding may help deaf people.
Karns: We've learn something new about the deaf brain and how sensitive the hearing areas are the touch and the deaf and also to vision. And there's a lot more work to do, but this discovery might support the use of new approaches for education of deaf people. The more we know about the way that the brain might adapt the better that we can tailor education and therapeutic intervention to deaf folks.
Akinso: She adds that the primary auditory cortex in people who are profoundly deaf focuses on touch even, more than vision. For more information on this study, visit www.nidcd.nih.gov. For NIH Radio, this is Wally Akinso.
Tips to stay healthy this holiday season
Balintfy: So the holidays are just around the corner – Thanksgiving is less than a week away. And that has some health implications when it comes to eating and stress. I’m talking with Dr. Griffin Rodgers, the director of NIH’s National Institute of Diabetes and Digestive and Kidney Diseases to get some tips to stay healthy this holiday season. First, Dr. Rodgers, when it comes to family gatherings and celebrations over the holiday season, is it possible to eat healthy without giving up favorite foods?
Rodgers: The holiday seasons can be filled with family, fun and festivities, but it can also be a stressful time. Holiday pressures can interrupt a person’s routine and make it even more challenging to follow plans to stay healthy.
When you’re getting ready to go to a family gathering or celebration and you know there’s going to be a lot of food around, planning ahead really helps. Here are some tips:
Don’t “save up” for big meals. Have a light snack before a party or family gathering. Eat an apple or half a turkey sandwich with a slice of reduced-fat cheese. Don’t skip meals-just eat a little less. This way, you will be less tempted to go overboard and eat more than you should.
Keep an eye on the drinks. Quench your thirst with water instead of soda or juice. And, limit the alcohol. It’s double trouble. Alcohol adds calories and it enhances your appetite.
Go easy on dessert. At celebrations, dessert is frequently the highlight of the event. Plan for it by eating more vegetables earlier in the meal, and saving calories and carbohydrates for a sliver of pie to add to a plateful of fruit.
Balintfy: Any tips for preventing holiday stress and letting that stress affect your health?
Rodgers: Try to be realistic and plan ahead. The holidays don’t have to be perfect, but with some planning, you can help prevent some of the situations that can create stress and affect your health. Here are some tips:
Plan ahead. Set aside specific times of the day for getting some physical activity. Plan your menus and make a shopping list so you have some healthy foods to eat during the holiday season.
Don't abandon healthy habits. Don't let the holidays become a free-for-all. Overindulgence only adds to your stress and guilt. Continue to get plenty of sleep and physical activity. If you do overindulge in eating too much, don’t be too hard on yourself up. Get back on track at the next meal.
Balintfy: Dr. Rodgers, what other tips would you offer that may help with managing stress during the holiday season?
Rodgers: Regular physical activity during the holiday season may boost your energy, clear your mind, manage any health problems like diabetes or high blood pressure, and help get some items checked off your holiday “to do” list. Here are some ways to make regular physical activity part of your holiday celebrations:
Go for a walk before or after a holiday meal. Ask your family and friends to join you. Physical activity is good for them too. If it is too cold out, turn up the music and have a dance contest with your family and friends.
Have fun with the kids. Pull them away from video games and celebrate the holidays with activities that will get everyone up and moving-flag football, kickball and jumping rope. You and your kids will burn off some calories without knowing it.
Keep track of your activity. As you keep track of holiday spending, you can also monitor your level of physical activity. Use a small notebook, portable devices or online tools to track your efforts. You can look back and feel good about your progress.
Balintfy: While eating favorite foods and desserts and exchanging gifts are central to many family gatherings, how can families also use this time together to help each other get healthier, perhaps give the gift of health?
Rodgers: Share family health history. Knowing your family health history can help you and your health care provider make the right decisions for your health.
Start a conversation about family health history. Ask questions. Talk about common health problems like diabetes and high blood pressure and whether anyone in the family has these conditions.
Exchange “healthy gifts.” Make a healthy food basket with fresh fruit, low-fat cheese, whole wheat crackers, and salsa dip and add a few healthy recipes.
Balintfy: Thanks to Dr. Griffin Rodgers, director of the NIH’s National Institute of Diabetes and Digestive and Kidney Diseases. The NIH has many resources to help you and your family and friends stay healthy this holiday season. Learn more about healthy eating and physical activity from the Weight-control Information Network at www.win.niddk.nih.gov. For diabetes prevention and management tips from the National Diabetes Education Program visit www.yourdiabetesinfo.org. And family health history and kidney disease details from the National Kidney Disease Education Program are available at www.nkdep.nih.gov.
And for more from the NIH’s National Institute of Diabetes and Digestive and Kidney Diseases, stay tuned for insight into arteries. That’s next on NIH Research Radio.
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Research on MRI screening for coronary artery disease
Balintfy: Coronary artery disease, also known as coronary heart disease, is the most common type of heart disease and is the leading cause of death in the United States in both men and women. Coronary artery disease happens when the arteries those are the blood vessels that supply blood to heart muscle become hardened and narrowed. This is due to the buildup of cholesterol and other material, called plaque, on their inner walls. When plaque builds up in the arteries, the condition is called atherosclerosis. Atherosclerosis can lead to serious problems, including heart attack, stroke, and even death. Researchers are now investigating a new way to look inside arteries before any symptoms of coronary artery disease appear. I’m talking with Dr. Ahmed Gharib, a radiologist and an investigator here at the NIH. Dr. Gharib, what are the challenges of getting useful images of the blood vessels of the heart.
Gharib: The problem with looking at the vessels that supply the heart is as you can imagine, it’s a smaller vessel. It’s about 2 mm and it’s sitting on moving organ which is beating at least 60 to 90 beats per minute which is also sitting on the diaphragm which is what we use to breathe so that’s also going up and down. So it’s almost like trying to image a spaghetti on a trampoline so that’s as simple as that and on top of that we’re trying to suppress the flow in the vessel itself, the blood flow in the vessel so that we can see the wall itself. Because there is blood within the vessel and there’s tissue outside the vessel so what we’re trying to do is suppress all of this, the motion and the flow and all of that together in order to look a the vessel wall itself.
Balintfy: Now a study has been testing a new technique for imaging using MRI or magnetic resonance imaging technology. Can you explain what that study is showing?
Gharib: So what we’re seeing is that when we compared 38 subjects, 12 of them were healthy subjects without any risk factors for heart disease or for contrary artery disease or atherosclerosis. We compared their vessel wall thickness to 26 subjects who do have, although they’re asymptomatic but some of them actually asymptomatic they have no symptom but have risk factors for coronary artery disease. We found that this technique is quite successful not only in imaging them but also is sensitive and more precise in separating the two groups.
The reason behind that mainly is that we’re imaging the vessel in almost a cinematic type of view so that we capture one still image that is perfect or close to perfect. It’s almost like imaging a race car and it’s moving very fast so if you take one shot at it, your chances of success is less than if you try to image it many or take multiple shots at it, there will be less blur in one of the images. Your chances of getting an image with less blur increases. So this is kind of similar to that. The process is being done in synchrony with the heart motion and the breathing motion and also the flow.
Balintfy: It makes me think of the motor drive on a camera, but timed to that bouncing spaghetti on a trampoline you described earlier. What do you think are the implications of this study Dr. Gharib?
Gharib: So this actually might have a few implications. First of all, it can be an early tool to detect vessel hardening or atherosclerosis. So somebody with risk factors or thinks he has problems in that area might come and look at their vessel wall in their coronary arteries and see if it’s thickened or not. At a certain point, if it is thickened then we can say okay this is a little bit above the normal. Mind you, we don’t have the complete normal values yet, we’re working on that.
And the other thing is follow-up. So now I have vessel wall thickening and I have atherosclerosis but I will want to take a medication or want to change my lifestyle. Now I can actually see if this is working, if what I’ve done has resulted in improvement in this vessel wall.
What’s also very important or potentially important is new drugs. So if there’s a new drug in the market, there’s a huge investment by the drug companies to put this drug and get it FDA approved. What this can do is actually show that this drug might be effective in reducing the vessel wall thickness early on before, because now we see a direct effect on the vessels.
Balintfy: To back up a little bit, there is imaging already being done now, but how is that different?
Gharib: There is but everything comes at a cost. So most of the imaging requires radiation. For example, the standard catheterization techniques require radiation. And there’s also a procedure involved with some minimal risk, but there is some. And that is usually in the delayed aspect or the later stages. Other imaging techniques such as nuclear medicine there’s also radiation involved. And then there is CT or computerized tomography requires radiation. MR is one of the ones that do not require radiation and they do use it, magnetic resonance, they use it for assessing the contractility or wall motion of the heart and sometimes perfusion of the heart. But also that for example to look at perfusion, you do require contrast agents or dyes that also comes with some minimal but existing risks and contraindication. Not everybody can tolerate it going into the MR scanner and so forth.
Balintfy: So these existing imaging options have risks. But it doesn’t sound like this new MRI technique is “ready for prime-time” quite yet. What are the next steps?
Gharib: What we’re trying to do is try to package it up so that when it goes out there it’s easier to use. But what is more important I think is trying to validate it in different populations to make sure that these initial findings will hold up in larger groups of patients and different types of patients.
Balintfy: Thanks to Dr. Ahmed Gharib who is with the NIH’s National Institute of Diabetes and Digestive and Kidney Diseases. For more on his research, visit www.niddk.nih.gov. And for details on coronary artery disease, visit www.nhlbi.nih.gov.
Balintfy: That’s it for this episode of NIH Research Radio. Please join us again on Friday, November 30 when our next edition will be available. Until next time, I'm your host, Joe Balintfy. Thanks for listening.
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