February 25, 2011
NIH Podcast Episode #0126
Balintfy: Welcome to the 126th episode of NIH Research Radio with news about the ongoing medical research at the National Institutes of Health—the nation’s medical research agency. I’m your host Joe Balintfy. Coming up in this episode: studies show how strategies can reduce dangerous college drinking, a potential treatment target has been discovered for alcohol problems, the genetics of impulsivity, how it can be inherited, and a promising strategy the may cure ringing in the ear. But first, this news update. Here’s Craig Fritz.
Fritz: Researchers funded by the National Heart, Lung and Blood Institute have found that cardiac arrests that can be treated by electric stimulation, also known as shockable arrests, occur more in public settings than in the home. In total, 79 percent of documented cardiac arrests in public were shockable arrests. Only 36 percent of in-home arrests were shockable. These findings help explain why home-based cardiac arrests have far lower survival rates than arrests that occur in public locations. The difference is not because of lack of witnesses at home who could call 911, nor is it caused by the absence of a nearby defibrillator. Instead, researchers found that certain types of cardiac arrests are more likely to occur in public, and those types are shockable arrests. The study noted that people who spend more time in public places typically are younger, more active, and have fewer chronic diseases—these people are more likely to have a different class of cardiac arrest. The researchers collected cardiac arrest data for over 14,000 people to examine if the location and type of arrest were linked to survival. The data spanned over 200 EMS agencies and their receiving hospitals across the United States and Canada. These findings appear in the January 27 issue of the New England Journal of Medicine.
Researchers may have demonstrated for the first time a potential memory enhancement with a naturally occurring substance. In a study funded by the National Institute of Mental Health, rats treated with naturally occurring insulin-like growth factor, or IGF-II, had significantly better retention and prevented forgetting of a fear memory. Researchers suspected that IGF-II plays a role in the formation and retrieval of memories. They note from this research in rats that IGF-II both strengthened a memory and delayed its forgetting when injected into the brain’s memory circuitry during a narrow window of time. The scientists hope to apply this knowledge to address clinical problems, including post-traumatic stress disorder.
Researchers funded by the National Institute on Alcohol Abuse and Alcoholism have found that the effectiveness of an experimental treatment for alcoholism depends on the genetic makeup of the individuals who receive it. The medication is currently used to treat nausea and vomiting, often following chemotherapy. It works by blocking receptors for the brain chemical serotonin. Serotonin mediates many processes in the brain, including the rewarding effects of alcohol. The researchers have found that two versions of a protein that regulate the levels of serotonin can significantly influence drinking intensity. Their study has shown that people with the first version of the protein reduced their average number of daily drinks to less than five while taking the medication. They also had significantly more days of abstinence compared to those who received a sugar pill. The medication’s effects were even more pronounced among individuals who possessed both versions of the protein, while subjects who had just the second version showed no improvement.
For this NIH News Update—I’m Craig Fritz
Balintfy: Thanks Craig. News updates are compiled from information at www.nih.gov/news. Coming up next, more stories on alcohol—a study on college drinking, and a potential treatment for alcohol problems—also, news on whether you can inherit impulsivity, and treating a ring in the ear that might sound like this: [4 kHz tone]… that’s when NIH Research Radio continues.
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NIH-supported study finds strategies to reduce college drinking
Balintfy: For this part of NIH Research Radio, we’ve got a couple stories on alcohol both from the National Institute on Alcohol Abuse and Alcoholism or N-I-tripple-A. First, researchers have conducted a trial of college and community alcohol prevention strategies at 14 large public universities in California. NIAAA-supported researchers have conducted the Safer California Universities study, to address the need for research on multi-strategy cooperative prevention approaches to reduce harmful college drinking, namely binge drinking. Binge drinking is pattern of drinking that typically means having 5 or more drinks for men, or 4 or more drinks for women, in about 2 hours. Wally Akinson has this report on what the researchers found.
Akinso: Highly visible cooperative projects can reduce harmful alcohol use among college students according to a National Institute on Alcohol Abuse and Alcoholism study.
Hingson: This was a study that was seeking to reduce binge drinking among college students.
Akinso: Dr. Ralph Hingson is the Director of the NIAAA’s Division of Epidemiology and Prevention Research.
Hingson: It took place at 14 colleges in the California public universities system. They had 7 matched pairs according to drinking results on a base line survey that they had done. Then they randomly allocated half of them to receive an intervention that involved a campus community partnership working on enforcement of alcohol policies that pertained to college students.
Akinso: Interventions included nuisance party enforcement operations, surveillance to prevent alcohol sales to minors, drunken driving checkpoints, social host ordinances, and use of campus and local media to increase the visibility of the interventions. Researchers conducted random surveys of students from each of the participating schools. Dr. Hingson says the survey documented that heavy drinking at off-campus parties was a common problem.
Hingson: In their baseline surveys they wanted to find out, where are the most drinking occasion that resulted intoxication occurring. And what they found was that about half of the parties that were Greek parties or off-campus parties they responded in surveys that they were doing with college students. They reported getting drunk at least once in the fall semester at parties in those occasions which was more than the residence halls or at bars in restaurants.
Akinso: To access the effectiveness of the interventions, the researchers measured the proportion of drinking occasions in which students got drunk in various settings. Dr. Hingson discusses the findings of the study.
Hingson: What they found was that in the communities where these interventions were implemented there were reductions in drinking into intoxication.
Akinso: Dr. Hingson believes these findings should give college administrators and surrounding communities some degree of optimism that student drinking is amenable to a combination of well-chosen, evidence-based universal prevention strategies. For more information, visit www.niaaa.nih.gov. This is Wally Akinso at the National Institutes of Health Bethesda, Maryland.
NIH-supported mouse studies suggest treatment target for alcohol problems
Balintfy: In this next report, Wally Akinso is back with another NIAAA expert. This story covers how a signaling pathway in the brain which has been linked to processes related to learning and memory might be involved in alcohol problems. The findings, published online in Proceedings of the National Academy of Sciences, also provide evidence that the pathway may be a promising new target for the treatment of alcohol problems. Here’s Wally.
Akinso: A molecular pathway within the brain’s reward circuitry appears to contribute to alcohol abuse according to a National Institute on Alcohol Abuse and Alcoholism study.
Noronha: The study that we are talking about shows that excessive alcohol consumption leads to an activation of a signaling complex—they’re many signaling mechanisms in the brain.
Akinso: Dr. Antonio Noronha is the Director of the NIAAA’s Division of Neuroscience and Behavior.
Noronha: This is a signaling complex of proteins called the mammalian target of rapamycin complex 1 or it’s also abbreviated as mTORC1.
Akinso: MTORC1 is a signaling pathway that helps regulate cellular processes throughout the body. In the central nervous system, mTORC1 has been linked to processes related to learning and memory. Since alcohol abuse disorders stem from a maladaptive form of learning and memory, NIAAA researchers hypothesized that mTORC1 might be involved in alcohol problems according to Dr. Noronha.
Noronha: Largely we think that addiction is a maladaptive form of learning and memory. And since this pathway has been implicated in mechanisms in learning and memory, we believe that this particular pathway, the MTORC1 pathway contributes to maladaptive form of memory that leads to or results in alcohol abuse disorders including binge drinking.
Akinso: In the laboratory studies, conducted with mice, researchers measured and found an increase in mTORC1 cellular products in the nucleus accumbens of mice that had consumed alcohol, which is an indication that alcohol activates the mTORC1 pathway. The nucleus accumbens is a brain region that in both rodents and humans is part of the reward system that affects craving for alcohol and other addictive substances. Dr. Noronha explains what researchers found when using a drug to block the mTORC1 pathway.
Noronha: Rapamycin is a FDA approved drug which is available on the market. This particular drug shows to decrease excessive alcohol consumption. The authors of the paper also show that it decreases binge drinking and alcohol seeking behaviors in rodents. Akinso: Dr. Noronha says that the findings show that the mTORC1 pathway is an important contributor to mechanisms that underlie alcohol-seeking behavior. For more information, visit www.niaaa.nih.gov. This is Wally Akinso at the National Institutes of Health, Bethesda, Maryland.
NIH-led study identifies genetic variant that can lead to severe impulsivity
Balintfy: From a brain pathway, to genetics—can we inherit impulsivity? This next story covers how another NIAAA-supported research team has found a genetic variant that may contribute to violently impulsive behavior. Impulsive behavior is a factor in many pathological behaviors—including suicide, aggression, and addiction, for example alcohol abuse—but it is also a trait that can be of value if a quick decision must be made or in situations where risk-taking is favored. Experts define impulsivity as action without foresight.
Goldman: Impulsivity is a normal dimension of behavior.
Balintfy: That’s Dr. David Goldman, chief of the Laboratory of Neurogenetics, at the National Institute on Alcohol Abuse and Alcoholism.
Goldman: But it’s also a dimension of behavior that can be involved in some significant psychiatric diseases.
Balintfy: He adds impulsivity plays a role in suicide, for example, and other diseases like alcoholism and other addictions.
Goldman: So in trying to understand these diseases, we’ve studied their components, such as impulsivity. And for our study, we DNA-sequenced people who were extremely impulsive.
Balintfy: Those extremely impulsive people were violent criminal offenders in Finland whose crimes were notably spontaneous and purposeless.
Goldman: These are, many of them, impulsive, murderers in fact. And we did that in the country of Finland because it’s a founder population in which the complexity of genetic diseases is reduced. And by sequencing these genes in these severely impulsive individuals, we were able to find a common severe genetic variant, which is known as a stop codon.
Balintfy: Dr. Goldman explains that modern Finns are descended from a relatively small number of original settlers, which means the genetic complexity of diseases in that country is reduced. Studying the DNA of violent criminal offenders within Finland increased the chances of finding the gene that influences impulsive behavior. It turns out:
Goldman: Everybody has this gene, and also everybody has severe genetic variants of this nature. But everybody doesn’t have this particular severe genetic variant. In fact, it’s found in over hundred-thousand Finns, but so far we haven’t seen it in any other population world wide.
Balintfy: And, Dr. Goldman notes, the genetic variant alone was insufficient to cause people to act impulsively.
Goldman: While there are people who are severely impulsive, who have this genetic variant, there are many people who carry it who are not.
Balintfy: He says the gene is sometimes necessary, but never sufficient. And he adds the discovery in this study does not mean impulsivity is explained.Goldman: We know that there are genetic factors in impulsivity, just like there are for all of the major personality traits. These personality traits, including impulsivity, are from 40-60 percent inherited and that means there are genes at the base that are influencing those. These are genes that are inherited from our parents and that are shared to some extent between us and our brothers and sisters. And so, what it does mean is that we’ve made some progress in beginning to identify the specific genes that are responsible for that general inheritance.
Balintfy: In the study, carriers of the gene variant who had committed impulsive crimes were male, and all had become violent only while drunk from alcohol. The researchers have also conducted studies in mice and found that when the equivalent gene is knocked out, or turned off, mice also become more impulsive. Studies of any alcohol interaction in the knockout mice are ongoing. But so far, taken together, these findings could lead to a better understanding of some aspects of impulsivity and ultimately may lead to strategies for diagnosing and treating some clinically important manifestations of impulsive behavior. The researchers caution, however, that impulsivity is a complex trait with multiple genetic and environmental causes. For more on this study, and impulsivity, that website again is www.niaaa.nih.gov.
Coming up, research may stop the ringing that’s annoying for some, debilitating for others, that’s next on NIH Research Radio.
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Rebooting the brain helps stop the ring of tinnitus in rats
Balintfy: Welcome back. In the last episode of NIH Research Radio we heard in the News Update about tinnitus, also pronounced tinnitus [tin-EYE-tus]. Now we have more details on how researchers funded by the National Institute on Deafness and Other Communication Disorders have found a way to eliminate a persistent ringing in the ears. If you have tinnitus, it might sound something like this: [4 kHz tone]... but it isn’t really a sound.
Miller: It is a perception of sound in the absence of any external sound; so it might be a roaring, a hissing a buzzing–typically it’s a ringing sound–but there’s no external sound that another person could hear.
Balintfy: That’s Dr. Roger Miller, Program Director for Hearing and Balance at that National Institute on Deafness and Other Communication Disorders. I asked him if tinnitus is what we have after a loud rock concert...
Miller: That’s right. So if you asked how many people have actually experienced tinnitus, since most people understand what it is, everybody has for a short period of time. When we use the phrase tinnitus as a problem, we’re really talking about an ongoing, something that happens continually, and doesn’t turn off after a couple hours.
Balintfy: How many people is that?
Miller: Well, NIDCD looked at this carefully—you see a lot of different numbers out on websites – we came up with the estimate of 23-million and that’s based on the question of has it continued on for five or more minutes.
Balintfy: I see that there are around 10-million people who are severely bothered by tinnitus.
Miller: And that’s the people we really would like to be able to help first, and those are the people that are driven to really extreme forms of behavior trying to eliminate this perception, this really bothersome and debilitating to them.
Balintfy: Is there is no cure or treatment?
Miller: There is no treatment, but there are a couple things that can help. There’s sound masking therapy that will help push that phantom percept into the background or just barely mask it so it’s quite noticeable. And there are some behavior therapies that will help the patients learn how to deal with this and find a way of making it less bothersome. And those are really quite good but we’d like to have an actual cure.
Balintfy: Who are the people most affected by tinnitus?
Miller: Typically the people that have sensory neural hearing loss. So some sort of acoustic trauma that has progressed to a point that they have a change in their ability to hear. So if you damage your cochlea or auditory nerve, let’s say, the blood supply or you have a tumor growth that damage the auditory nerve, those are the people that almost always get tinnitus. Some of the other people that have noise-induced hearing loss will get tinnitus, but we really don’t know the difference between patients that do or don’t get tinnitus based on that cochlear damage.
Balintfy: It’s worth noting here tinnitus is not a disease it is a symptom that something is wrong in the auditory system. The auditory system includes our ears, the cochlea or inner ear, the auditory nerve, and the parts of the brain that process sound. In tinnitus, that part of the brain that processes sounds — the auditory cortex — delegates too many neurons to some frequencies, which is a change in the way the brain processes auditory or sound information. But a recent research study is showing hope for those suffering from tinnitus.
Miller: It’s a very interesting observation that pairing vagul nerve stimulation with sound stimulation in a very novel and careful way has been able to help these patient, well, in this case the patients were rats.
Balintfy: The vagul nerve, that’s a nerve in the neck?
Miller: That’s right. ...The vagul nerve, so that’s not typically associated with auditory processing, but again the change in the input to the whole brain has changed the way it’s processed auditory information.
Balintfy: It’s like hitting a reset button?
Miller: That would be one way of saying it.
Balintfy: How promising is this, something soon?
Miller: Well the nice thing about this approach is takes a type of nerve stimulation that’s already been developed, it’s already been approved for one use, and if we could just slide that over laterally and start using it for tinnitus, it could go forward in a relatively straight forward and fast manner, and that’s what we’re looking for is new ways to help tinnitus patients.
Balintfy: Thanks to Dr. Roger Miller, Program Director for Hearing and Balance at that National Institute on Deafness and Other Communication Disorders. For more information on tinnitus, this study and how hearing works, visit www.nidcd.nih.gov. In addition to tinnitus, you can find information on ear infections, noise-induced hearing loss and much more.
For now, that’s it for this episode of NIH Research Radio. Please join us again on Friday, February 11 when our next edition will be available. We’ll have a feature on a condition that can be an early sign of depression in women:
“So not only women with this condition more likely to get depressed, the depression shows up in association with the menstrual cycle irregularity even before they get the diagnosis.”
If you have any questions or comments about this program, or have story suggestions for a future episode, please let me know. Best to reach me by email—my address is email@example.com. I’m your host, Joe Balintfy. Thanks for listening.
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