Post-traumatic Stress Disorder: 1 Part Genes, 1 Part Experience

Diagnosis Posttraumatic Stress Disorder. Medical note surrounded by neurologic hammer, mental status exam with an inscription in large letters psychiatric diagnosis of Posttraumatic Stress Disorder

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Post-traumatic stress disorder (PTSD) is a debilitating, psychiatric disorder that can occur following exposure to trauma or extreme stress. While anyone who has experienced trauma can develop PTSD, it is most often associated with military veterans. Not everyone who has experienced trauma will develop PTSD—in fact, the majority of people exposed to trauma do not develop the disorder. Whether or not someone develops PTSD depends on a person’s perception of stress, which is shaped by life experiences, genetics and behavior.

The genetic aspect of PTSD has two parts: genes and environmental factors such as life experiences. The idea that genes play a role in PTSD is getting a lot of attention lately. The effect of genes and environmental factors together is called gene-environment interaction. Scientists have identified a gene that may contribute to PTSD, particularly in people who have experienced early-life trauma.

Researchers think that variations in genes can play a role in determining how someone responds to a traumatic event or can even make them more likely to develop PTSD. One type of gene variation is on a particular gene called FKBP5 that has been associated with PTSD. FKBP5 has a related protein that is involved in the body’s response to stress. If a variation occurs in FKBP5 that causes irregular function of its associated protein, it will affect a person’s stress response. This in turn could influence the development or severity of PTSD symptoms. Studies of people with PTSD who have a FKBP5 variation and also experienced early-life trauma, such as childhood abuse, show a significant gene-environment interaction. More specifically, the combination of the gene variation plus early-life trauma resulted in more severe PTSD symptoms compared to people who had not experienced trauma.

Scientists hope the results of studies like these will lead to new and more effective PTSD treatments.

Donna CioffiDonna Cioffi, PhD, is an associate professor in the department of biochemistry and molecular biology at the University of South Alabama. She studies the role of the protein FKBP51 in calcium signaling in pulmonary endothelial cells.

Cardiovascular Consequences of Wildfires and Climate Change

Night long exposure photograph of the Santa Clarita wildfire

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This week, there’s been nonstop media coverage of the massive wildfires in California—including the Mendocino Complex fire, now considered the largest fire in state history. In California alone, more than 13,000 firefighters are battling flames that have scorched more than 600,000 acres. The U.S. is not the only country experiencing an uptick in catastrophic fire events. As global temperatures rise, European firefighters are also facing longer, hotter and more damaging wildfire seasons than ever before.

Firefighters and other first responders are at risk of burns and smoke inhalation as they work to contain these massive blazes. In addition, they may also be at risk of cardiovascular damage related to the stress and physical challenges of battling extreme heat and fire. Dao H. Ho, PhD, recently wrote about these cardiovascular risks on the I Spy Physiology blog: “The incidence of fires increases in the U. S. during the summer months. Firefighters fight almost twice as many fires in the summer compared to the rest of the year. On top of dealing with the extreme heat (sometimes over 700 degrees F!), these first responders face extreme physical exertion, mental stress and smoke inhalation on the job. All of these factors together can place firefighters in immediate danger of heat exhaustion, heatstroke and heart problems. In fact, firefighters are up to 136 times more likely to die of coronary artery or heart disease during or soon after they suppress a fire.”

Climate change may be causing more health problems for regular citizens, too. A recent study linked an increase in heart attacks to extreme climate change-related temperature fluctuations. Research in the American Journal of Physiology—Cell Physiology also found that higher temperatures are causing a boom in a fungus that worsens allergy and asthma symptoms. Unfortunately, this may just be the tip of the quickly melting iceberg.

The Centers for Disease Control and Prevention has developed resources and tips for those in areas threatened by wildfires including guidance to help protect emotional and physical well-being after a fire. Visit www.cdc.gov/disasters/wildfires/index.html to learn more.

Stacy Brooks

Taking Tests in a Heat Wave is Not So Hot

Businesswoman Sweating At Work With Broken Conditioner

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You know the feeling: It’s like a sauna outside. Sweat pours down your face and body. You drink gallons of water and still can’t get cool. You don’t want to exert much physical effort. The dog days of summer are here, but with a heightened intensity. Record-breaking heat in the U.S.—with North Texas seeing triple digit temperatures for days on end and daytime highs in Southern California reaching 117 degrees F—along with soaring global temps put many people at risk for dehydration and heat stroke. It’s August and the heat is on.

A new study suggests that a heat-induced “muddled” brain can affect the way you learn—more so than just feeling uncomfortable. Researchers studied two groups of students during a heat wave. One group lived in air conditioned apartments that were cooled to 71 degrees F. The other group’s living spaces were not air conditioned and averaged about 80 degrees F. The students were given tests that assessed their math skills, speed, memory and attention as soon as they woke up for 12 days.

Students who lived in the air conditioned buildings answered more questions correctly and had faster response times than the students who lived in hotter buildings. The researchers noted that their study is just one more sign that heat stress can have a negative effect on the mind as well as the body. Although previous studies suggest that, in some cases, heat stress reduces blood flow to the brain, it’s unclear how heat impacts cognitive skills and scientists have much more to learn about the body’s response to extreme heat.

If you like the heat, it’s okay to soak up some rays and enjoy the warmth. Just remember to take steps to protect your skin and kidneys. And if you have test-taking in your future, make sure your air conditioner is working!

Erica Roth

Virtual Reality Gives Students a New Look at Physiology

 

VR Dreamery Lab

A student immersed in a virtual reality depiction of heart disease. Credit: Yasina Somani

This summer I had the opportunity to design and teach a two-week course as part of the Summer Discovery program at Penn State. The program brings high school students from all over the globe, including Taiwan, Japan and Puerto Rico, to central Pennsylvania to attend college preparation courses.

Taking the lead in developing and teaching a course was a refreshing departure from my role as a graduate teaching assistant during the school year. My course was an introduction to exercise physiology that focused on the physiological basis for exercise training to prevent and treat chronic disease. As we began, I sensed that my students didn’t fully understand the relationship between exercise and disease. So I organized a field trip to the Dreamery at Penn State.

The Dreamery is a space on campus that houses various immersive technologies such as augmented and virtual reality. Each of us had a chance to try out a physiology virtual reality application. Outfitted with headsets and controllers, we were transported into the virtual world.

The students found themselves surrounded by the small airways and air sacs (bronchioles and alveoli) in the lungs. They used the controllers to change the settings and observe what the structures would look like in someone with asthma or chronic obstructive pulmonary disease. They walked through the coronary arteries of the heart as they developed fatty streaks and sticky buildup (plaque) in a process called atherosclerosis. Atherosclerosis eventually leads to heart disease. Students observed a demonstration of a procedure—called an angioplasty—that widens the artery and places a mesh tube called a stent to keep an artery open. Although the application we tested did not have accompanying narration, a separate monitor displayed what the students were viewing and I was able to offer commentary.

In an article published in Advances in Physiology Education, researcher Daniel Richardson points out several potential pitfalls of using virtual reality for teaching physiology. One is that the complexity of physiological systems may not be considered fully in the virtual world, which may lead to misconceptions and an oversimplified view of course material. However, educators may overcome this hurdle by providing narration and “guided tours” as I did with my class.

My students said the application was “impressive” and “fun,” suggesting that this tool can help with retaining information learned in class. After my experience with the technology, I think virtual reality provides a good visual representation of the body’s systems. It may be a useful tool to supplement conventional physiology teaching and enhance learning.

Yasina SomaniYasina Somani, MS, is a PhD student in the Cardiovascular Aging and Exercise Lab at Penn State. She is interested in studying the effects of novel exercise and nutritional therapies on cardiovascular outcomes in both healthy and clinical populations.

Firefly “Magic”

Firefly blurred flying at dusk while lighting up

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Here come real stars to fill the upper skies,
And here on earth come emulating flies,
That though they never equal stars in size,
(And they were never really stars at heart)
Achieve at times a very star-like start.
Only, of course, they can’t sustain the part.

–Robert Frost, “Fireflies in the Garden

The warm glow of fireflies—also called lightning bugs—may seem magical as it fills the summer evening skies. However, that’s not magic behind their blinking yellow lights. It’s a fascinating chemical reaction that scientists have been able to use to study important events that take place in the cells of many living things.

Fireflies use their flashing lights to ward off predators, attract a mate and identify themselves to others of their own species. Their glow is what scientists call bioluminescence, a fancy term to describe the biochemical production of light by living things. In the case of fireflies, these little bugs make a chemical called luciferin and a protein called luciferase. These lightning bugs control the light flashes by releasing oxygen which, when combined with other chemicals, causes their bodies to glow.

Scientists also have multiple uses for the very same luciferase reaction. They can artificially manufacture the ingredients that make up the chemical reaction to study how genes are activated in living cells. Using the luciferase reaction, scientists can also watch biological processes in living beings in real time. They can even use the chemical reaction to test food safety.

Recreating the glow of lightning bugs is an excellent example of how the study of one small organism can lead to potentially huge advances in human health. Without the “magic” of the firefly luciferase reaction, we might still be in the dark about so much that happens in our cells.

Interested in fireflies and science? Become part of the Firefly Watch Citizen Science Project to help scientists study changes in firefly populations.

–  Audrey Vasauskas 

The Latest in Physiological Education: A Report from ITL

Physiology educators gathered last month in Madison, Wis., for the third APS Institute on Teaching and Learning (ITL) conference. Attendees discussed the latest trends in science education through a series of talks, interactive workshops and poster sessions. Read on to learn more about what’s new and what’s next in the classroom.

A performance form with excellent checked off

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As recently as a couple of decades ago, the idea of online learning was in its infancy. The physical classroom was the center of the action when it came to delivering and receiving course content. As a result, the students who attended lectures were likely to outperform those who skipped class. However, researchers from the University of Central Florida College of Medicine found that the grades of medical students who skipped non-mandatory class sessions in favor of reviewing digital content didn’t suffer.

Researchers from the University of Iowa also found online learning to be beneficial to students. Their study showed that students performed better and were less anxious when they attended a “blended” course, which presented online content together with some face-to-face teaching.

Forgetting

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Don’t beat yourself up the next time you’ve forgotten something you’ve studied. Your memory is making room for new information, which actually plays a positive role in learning. Robert A. Bjork, PhD, from UCLA, explained to ITL attendees how forgetting can enrich and enhance learning and shouldn’t necessarily be thought of as a bad thing.

 

Researchers at ITL also discussed:

Read more highlights from this year’s conference.

Erica Roth 

Here Comes the Sun (and the Heat)

A thermometer shows high temperatures against the sun, a blue sky and a few white clouds.

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Summer is in full swing, and with a near-peak number of daylight hours, chances are good that there is still plenty of light left to enjoy once your workday is done. Before you get outside and bask in the sun and heat, check out these I Spy posts that explain how your body responds to hot weather and provide tips to help you stay safe this summer:

Have a safe, sunny and fun summer!

Erica Roth

A Scientist’s Quest to Understand the Box Jellyfish that Almost Killed Her

About 50 different species of box jellyfish live in the Pacific Ocean and on the coasts of Florida and New Jersey. When the box jellyfish stings, it shoots venom from its tentacles into a person’s flesh with as much pressure as a bullet fired from a gun. The unique venom contains many different types of poisonous substances called toxins, including some of the same found in dangerous bacteria and in cobra’s venom. The venom quickly pokes holes in the red blood cells that carry oxygen throughout the body, causing a spike in heart rate and bleeding in the brain. If you are stung with a large amount of venom, it only takes minutes for the venom to stop your heart. If that’s not scary enough, box jellyfish are clear, making them almost invisible to the human eye when swimming in the ocean.

Angel Yanagihara 1

Angel Yanagihara, PhD, studies box jellyfish on Waikiki. Credit: A. Yanagihara

Angel Yanagihara, PhD, a professor at the University of Hawaii at Manoa, has made it her life’s mission to learn everything she can about the box jellyfish and its deadly venom. When I first met Yanagihara, I was intrigued by her passion for studying the creatures. It was only after a few conversations with her that I found out she nearly died after being stung by a box jellyfish while she was swimming off the coast of Waikiki. Surprisingly, in 1997—when Yanagihara was stung—very little was known about box jellyfish venom. Since that time, she has discovered what is in the venom and how to purify it to understand its toxic effects in the human body. She has also developed a topical cream that deactivates the venom before it causes harm to the body. This novel first-aid approach to treating a box jellyfish sting can help prevent the venom from killing.

Angel Yanagihara 2

An early morning dive. Credit: A. Yanagihara

Yanagihara is currently studying the body’s response to the venom in the hopes of increasing a person’s chances of surviving a box jellyfish sting. I am lucky enough to be part of her study team that is looking at the physiological responses that occur after a sting. For her studies, Yanagihara goes diving very early in the morning, before sunrise. This time, she is sure to protect herself from the deadly box jellyfish by wearing a full-body wet suit.

 

Dao Ho, PhD

Dao H. Ho, PhD, is a biomedical research physiologist at Tripler Army Medical Center. The views expressed in this blog post are those of the author and do not reflect the official policy or position of the U.S. Department of the Army, U.S. Department of Defense or the U.S. government.

March to the Beat of Your Own Drum

Audrey's kids drumming

Audrey’s kids enjoying a drum circle. Credit: Audrey Vasauskas

My two young children absolutely love to beat on drums (or tables, chairs, any flat surface really). I recently took them to a family-oriented drum circle. They had a blast, and I was surprised at how good I felt too, both during and after the event. It turns out all that drumming—especially with others—is beneficial in a variety of ways.

Music has a positive effect on overall mood and mental health. Drumming has recently been studied for its stress- and anxiety-reducing effects. With the rise in popularity of drum circles, group drumming especially seems to be good for mental and physical health. Drumming improved mental health scores, with participants reporting less depression and lower anxiety levels.

Studies suggest that mental health and inflammation may be linked. Inflammation is how the body responds both to outside invaders, such as viruses or bacteria, and to factors that may harm the body, such as stress. White blood cells and special chemical messengers in the immune system help protect the body in a process that can be likened to “calling up the troops.” The increased protection leads to inflammation. Once additional protection is no longer needed, the anti-inflammatory chemical messengers switch off their response. The whole process is usually short-lived. However, when inflammation sticks around for too long, it can affect body and mood in a number of negative ways, which sometimes leads to depression and anxiety.

The link between physical and mental health and drumming is complex, but it seems the benefits are partially due to this effect on the immune system. Chemical messengers that increase inflammation are reduced after taking part in a group drumming activity, while anti-inflammatory messengers are increased. The creative nature and shared experience of drumming may explain these chemical changes—music has been shown to reduce nervous system activity that is associated with stress. So grab some friends, get on those drums—and be loud!

Audrey Vasauskas

How Do Frogs Survive the Cold? By Freezing

Frog

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They aren’t moving. They’re not responding to touch or light. Their hearts aren’t beating. They’re no longer breathing. Their skin is ice-cold and hard to the touch. By that description, you probably don’t think I’m describing living things. However, there are some animals that survive like this because of a process called freeze tolerance.

Unlike mammals, whose bodies are always working to maintain a constant temperature, cold-blooded animals (ectotherms) are at the mercy of their environment. As a result, when the temperature plummets, they have to come up with a physiological means to survive the bitter cold winters.

Bugs and amphibians are the freeze-tolerant animals researchers study most often. Among amphibians, a few select frogs show a clear freeze-tolerance response. Large amounts of their bodily fluid freeze into ice particles to help them make it through the winter.

The physiological changes that prepare freeze-tolerant animals for cold weather begin as the temperature drops, but they don’t happen overnight. These animals distribute substances called cryoprotectants, which allow them to get colder than freezing while shielding them against dehydration and other cell changes that can occur when ice forms. Once frozen, the animals can withstand temperatures ranging from 32 to -22 degrees F, depending on the species. Freeze tolerance can last from weeks to months. Cycling through this process is a must for any frog that wants to see the next summer.

However, thawing may be just as important as freezing. Freeze-tolerant animals likely go through several freeze-thaw cycles, during which the distribution of cryoprotectants and tolerance to the cold increases. This suggests that the cryoprotective process isn’t finished after the first freeze and is a cumulative process as the winter grows colder. When spring arrives and the weather returns to consistently above-freezing temperatures, the animals thaw, their hearts start beating again and they continue on without negative effects.

Scientists want to learn more about freeze tolerance from the animals that do it so well. In case you missed it, humans can’t freeze and thaw themselves. By studying the physiological changes in freeze-tolerant species, researchers can apply this work to mammals, such as by storing organs for later use and keeping cell lines healthy while in storage. Studying an “ideal” organism that has overcome a functional problem allows scientists to better understand those problems in mammals. Therefore, comparative physiologists continue to research the unique traits of various organisms to understand how evolution has already handled these challenges.

Brian StogsdillBrian Stogsdill is a graduate student at Wright State University, in Dayton, Ohio, currently finishing his doctorate in biomedical science. Stogsdill researches freeze tolerance and aquaglyceroporins (a family of proteins that conduct water).