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March 12, 2010
NIH Podcast Episode #0105
Balintfy: Welcome to episode 105 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 a pair of reports on Autism Spectrum Disorders, the latest research there; some new knowledge resources about genes, what may help health professionals and patients; plus, insight on a study of age-related macular degeneration. But first, this news update.
News Update
Balintfy: Results of a clinical trial conducted during the 2008-09 flu season show that immunizing children against seasonal influenza can significantly protect unvaccinated community members as well. Researchers wanted to determine if immunized children could act as a barrier to limit the spread of influenza to the wider, unvaccinated community. This concept is known as herd immunity. Researchers recruited volunteers from 46 Canadian Hutterite religious colonies that have limited contact with surrounding, non-Hutterite populations. Of the 947 children who participated in the trial 502 received the seasonal influenza vaccine. The researchers found that influenza vaccination was 61 percent effective at indirectly preventing illness in unvaccinated individuals—that is, herd immunity—if they lived in a colony where approximately 80 percent of the children had received flu vaccine.
Also about the flu, researchers have long puzzled over why it becomes so much more active in winter. A new study reveals that dry air is one likely culprit. By comparing 31 years of influenza death rates to nationwide absolute humidity readings, researchers found that there were often significant drops in absolute humidity in the weeks prior to a flu outbreak. Absolute humidity is a measure of how much water vapor is in the air. Researchers add that a dry period is not a requirement for triggering an influenza outbreak, but one was present in 55-60 percent of the outbreaks analyzed. Researchers conclude that big drops in absolute humidity appear to increase the likelihood of a flu outbreak. This discovery might be used in the future to help predict when outbreaks will occur. It also has implications for treating influenza outbreaks: For example, hospitals may pay more attention to controlling humidity levels.
An independent panel recently confronted a troubling fact: pregnant women often face so-called vaginal birth after cesarean, or VBAC, bans. This means women, even those at low risk for complications, have limited access to clinicians and facilities able and willing to offer a trial of labor after previous cesarean delivery. According to the panel, a trial of labor is a reasonable option for many women with a prior cesarean delivery. They also urged that current VBAC guidelines be revisited, malpractice concerns be addressed, and additional research undertaken to better understand the medical and non-medical factors that influence decision making for women with previous cesarean deliveries.
And this last note, NIH Director Dr. Francis Collins has been named a recipient of the Albany Medical Center Prize in Medicine and Biomedical Research. He and two others are honored for their leading role in mapping the human genome. While accepting the honor, Dr. Collins declined his portion of the half-million dollar prize in order to comply with government ethics rules. Dr. Collins’ co-recipients are Dr. Eric Lander, director of the Broad Institute at the Massachusetts Institute of Technology and Harvard University, and Dr. David Botstein, director of the Lewis-Sigler Institute for Integrative Genomics at Princeton University. Collectively, the work of Drs. Collins, Lander, and Botstein has unlocked the human genome, paving the way for easier identification and study of genes associated with common diseases such as diabetes, cancer and heart disease. The Albany Medical Center Prize, often called "America’s Nobel," honors scientists whose work has translated from "the bench to the bedside" resulting in better outcomes for patients.
News updates are compiled from information at www.nih.gov/news as well as the Research Matters e-magazine. Coming up after this break, a pair of reports on Autism Spectrum Disorders, and much more. Stay tuned.
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Disrupted Brain Circuits in Autism Spectrum Disorder
Balintfy: Autism Spectrum Disorders are complex developmental brain disorders that affect an individual’s ability to communicate and interact with others socially. In a recent study, conducted at the National Institute of Mental Health, scientists have identified a circuit in the brain which plays a key role in social processing and which is disrupted in autistic individuals. Anahita Hamidi files this report.
Hamidi: We often take our ability to understand a subtle joke, to pick up on sarcasm and to relate to others socially for granted. Individuals who are affected by autism are unable to process these social cues. Recent findings have uncovered some key brain areas that may be essential in processing this social information and which are disrupted in autistic individuals.
Dr. Martin: What's been termed the "social brain" has been based on about 20 years of research.
Hamidi: Dr. Alex Martin is a senior investigator at the National Institute of Mental Health and the chief on the Section of Cognitive Neuropsychology in the Laboratory of Brain and Cognition.
Dr. Martin: And these areas all seem to work together as a circuit to allow us kind of to negotiate our social world and it's that circuitry that seems to be most dysfunctional, certainly in our so-called high-functioning individuals on the autism spectrum.
Hamidi: Different people with autism can have very different symptoms. Health care providers think of autism as a "spectrum" disorder, a group of disorders with similar features. One person may have mild symptoms, while another may have serious symptoms. Dr. Martin says, the high-functioning individuals are still able to use these brain circuits to process non-social information. The deficits, he explains, are restricted to the ability to process social information.
Dr. Martin: What we've been finding with our research is that this particular group of individuals have certain types of deficits in the domain of social processing, that has to do with the way they orient to the social world and their ability to kind of understand what’s going on socially and it's really restricted to kind of social interactions as opposed to interactions with other kinds of objects.
Hamidi: Although only individuals on the high-functioning end of the autism spectrum were selected for the study, the results from the brain scans can still give some information about what brain circuits might be affected across the autism spectrum. Dr. Martin explains.
Dr. Martin: So, with our high-functioning individuals we take advantage of analyses where we just record data when people are simply resting in the scanner not really doing anything but lying there and we've been able to show—we could pick out the dysfunctional network by comparing what are these "resting-state scans" in these individuals and compare them to their control group.
Hamidi: Dr. Martin continues that the results of these studies, not only provide insight into what circuits are dysfunctional in high-functioning autistic individuals, but may provide some clues about which brain areas may be affected in all autistic individuals.
Dr. Martin: So in other words, these analyses suggest that one might be able to detect abnormalities in specific circuits in the brain in individuals that would normally be way too impaired to perform our task.
Hamidi: Dr. Martin spoke recently at the Clinical Center Grand Rounds lecture. To hear his presentation, titled "Cognition and Brain Functional Connectivity in Autism" visit the Clinical Center website: clinicalcenter.nih.gov. For more information regarding this study and autism research, visit www.nimh.nih.gov. This is Anahita Hamidi, National Institutes of Health, Bethesda, Maryland.
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NICHD Investigates Connection Between Low Blood Cholesterol and Autism in Children
Balintfy: In this next report, also dealing with Autism Spectrum Disorders, we turn to Nicole Martino from Clinical Center Radio. She reports on the details of just one of many trials that are under way now.
Martino: The Centers for Disease Control estimate that an average of 1 in 150 children in the United States have an autism spectrum disorder. Unfortunately, much is unknown about the causes and risk factors of autism, although a quick search on clinicialtrials.gov for autism studies yields almost 200 results. Dr. Forbes Porter, from the Eunice Kennedy Shriver National Institute of Child Health and Human Development is a principal investigator of one of those studies, a study at the NIH Clinical Center that is investigating the connection between autism and low blood cholesterol.
Dr. Porter: We got interested in autism because we study another rare disease, a very rare disease, called Smith-Lemli-Opitz Syndrome in which there is a problem in cholesterol formation, children's bodies don't make enough cholesterol. Those patients frequently have autistic symptoms, so initially we were interested in finding out whether we could find Smith-Lemli-Opitz patients in children who had previously only been diagnosed with autism. We didn't find the Smith-Lemli-Opitz patients but we found that a higher then expected percentage of children with autism had low cholesterol.
Martino: The study plans to enroll children between the ages of 4 and 11 who have been diagnosed with an autism spectrum disorder.
Dr. Porter: Autism spectrum disorders encompass children who have problems in certain domains of interaction, communication, social interaction and they can often have sort of repetitive activities.
Martino: The study involves blood drawing, multiple questionnaires, and behavioral assessments. This study is a multi center trial, in addition to the NIH Clinical Center it is also being conducted at Ohio State University and the Kennedy Krieger Institute in Baltimore, Maryland. This study is also sponsored in part by Autism Speaks, one of the nation's largest autism science and advocacy organizations dedicated to funding research into the causes, prevention, treatments and cure for autism.
Dr. Porter: It may give us an insight into a small subet of autistic patients on what might be causing or underlying the autism in those children. It will also teach us whether in that small group of autistic patients, because the majority do not have low cholesterol, whether we can improve their symptoms by giving them cholesterol.
Martino: If you would like more information about this study or one of the approximately 1,500 other studies offered at the NIH Clinical Center, log on to http://clinicalcenter.nih.gov, or e-mail prpl@mail.cc.nih.gov.
Balintfy: That’s Nicole Martino with Clinical Center Radio. Stay tuned for another Clinical Center Radio report later in the program.
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NHGRI Launches Online Genomics Center for Educators of Nurses, Physician Assistants
Balintfy: To address the growing need for genetic and genomic knowledge among health care professionals, the NIH Genome institute launched an online tool to help educate the next generation of nurses and physician assistants about this new frontier. Wally Akinso has the details.
Akinso: The National Human Genome Research Institute has launched an online tool to help educators teach the next generation of nurses and physician assistants about genetics and genomics. Dr. Jean Jenkins, NHGRI's senior clinical advisor to the director, says this tool is part of NHGRI's effort to address the need among health care professionals for knowledge in this area.
Dr. Jenkins: We worked to design the Genetics/Genomics Competency Center, we call G2C2. It's a free web-based collection of materials on genetics and genomics. And it's been developed to facilitate the educator’s ability to find resources and curricular material with which to teach genetics and genomics to nurses and physician assistant students.
Akinso: Nursing and physician assistant educators can use the Genetics/Genomics Competency Center to find and download materials for their classrooms according to Dr. Jenkins.
Dr. Jenkins: Educators can browse disciplines specific libraries to find learning resources and curricular materials in varied formats. And the library currently includes things like websites, and web modules that might include information about genetics and genomics of value to educator. Course information, books, articles, power point presentations and other curricular material that has been peer reviewed and found to be a value for the education of nursing and or physician assistant students.
Akinso: Dr. Jenkins hopes that this tool expands to include other health care professions, such as pharmacists and physicians.
Dr. Jenkins: G2C2 is a resource that as we enter the era of personalized medicine, establishing genetic and genomic literacy is an urgent concern for those who educate health professionals. And we hope that this online resource will provide a valuable new tool for meeting that challenge.
Akinso: To access this resource, visit www.g-2-c-2.org. This is Wally Akinso at the National Institute of Health, Bethesda Maryland.
Balintfy: Coming up after this break, we turn our attention to eyes in another report from Clinical Center Radio. We’ll be right back.
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New NEI Study Investigates Age-Related Macular Degeneration
Balintfy: Keeping our eyes healthy is important throughout our lives, yet millions of Americans lose some of their vision every year to a variety of causes. One of those causes is known as age-related macular degeneration or AMD. AMD is a disease associated with aging that gradually destroys sharp, central vision necessary for seeing objects clearly. Bill Schmafeld reports that AMD is one of the leading causes of blindness in the United States.
Schmalfeldt: Dr. Catherine Meyerle is the principal investigator of a National Eye Institute protocol studying new treatments for this disorder.
Dr. Meyerle: There are two different forms, the wet form which is also known as the neovascular form, and the dry form. There are different stages of the dry form; there is early, intermediate or advanced.
Schmalfeldt: The presence of yellowish deposits under the retina called "drusen" are the first signs of early AMD. People with intermediate AMD have a significant presence of drusen . Advanced AMD involves a breakdown of light sensitive cells and supporting tissue in the central retinal area. This breakdown can cause a blurred spot in the center of your vision which may get bigger and darker over time or it can make straight lines appear wavy. Advanced AMD presents itself in two forms: wet and dry. This study specifically addresses wet age-related macular degeneration.
Dr. Meyerle: Wet macular degeneration, unlike the advanced dry, instead of a thinning of tissue you get abnormal blood vessels that grow underneath your retina. These abnormal blood vessels tend to bleed and leak fluid and this fluid and blood goes into your macula itself. And the problem with fluid and blood in your macula is it distorts the cells that enable you to see, the photoreceptors, so they don't function as well and this can ultimately if not treated, lead to scarring, and once there is scarring we can't reverse scarring. And if you have a scar on your macula you will have a central area where you can't see, we call it a scotoma. If I have a scar on my macula, I might look at someone's face and not be able to see their nose and part of their eyes, maybe I'll just be able to see their chin.
Schmalfeldt: More than 1.7 million Americans have the advanced form of AMD with about 200,000 new cases of wet macular degeneration diagnosed each year. This study is seeking participants 50 years of age and older with a diagnosis of wet age-related macular degeneration to study those leaky blood vessels Dr. Meyerle described. This protocol provides participants with the standard treatment for this disorder, a drug called Lucentis, although it does involve a little something extra.
Dr. Meyerle: This study is looking at high speed indocyanine green angiography. We call it ICG for short. ICG is an imaging test where we inject green dye in your arm and it circulates in your body and it helps us visualize the vessels underneath the retina called the choroid, and this is where you can develop the abnormal vessels associated with wet macular degeneration… This study is different because we are looking at the actual abnormal vessels themselves as opposed to looking just at the fluid and the leakage.
Schmalfeldt: Essentially, this study combines standard treatment of wet AMD combined with the ICG to see if there is any effect of the medication on the abnormal blood vessels themselves or if it only affects the fluid. This is important information because currently people may respond differently to Lucentis.
Dr. Meyerle: With Lucentis therapy, some patients need injections monthly for years, and other patients, after they have a few induction injections, they can go a long time without an injection. And why is there this variability in response to therapy? There might be something different about these characteristics of these abnormal blood vessels and that's what this study is designed to look at.
Balintfy: If you would like more information about this study or one of the 1,500 other studies offered at the NIH Clinical Center, visit the website, clinicalcenter.nih.gov, or e-mail prpl@mail.cc.nih.gov. Special thanks to Bill Schmalfeldt at Clinical Center Radio for this report. Again to hear other Clincal Center Radio podcasts, visit www.cc.nih.gov/podcast.
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Balintfy: That’s it for this episode of NIH Research Radio. Please join us again on Friday, March 26 when our next edition will be available for download. I'm your host, Joe Balintfy. Thanks for listening.
Announcer: NIH Research Radio is a presentation of the NIH Radio News Service, part of the News Media Branch, Office of Communications and Public Liaison in the Office of the Director at the National Institutes of Health in Bethesda, Maryland, an agency of the US Department of Health and Human Services.
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