Spotlight On: Tuberculosis

Pulmonary Tuberculosis

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If you’ve ever volunteered or worked in a hospital, nursing home or laboratory, you may remember having a tuberculosis (TB) skin test. But did you fully understand what TB is and why the tests are necessary? Though TB may not seem to be a major health concern in the U.S., this cunning disease remains a leading cause of death worldwide and a major risk to people with weak immune systems.

A strain of bacteria called Mycobacterium tuberculosis causes TB. People who are exposed to the bacteria may develop a form of the disease without actually being sick. This is called latent TB infection and means the body is able to fight the bacteria without spreading it to others. However, if the immune system is not in top-notch shape, the bacteria can multiply and develop into a dangerous active infection. Active TB infection is very serious and can be deadly if not treated.

An active TB infection can be spread easily, especially when the disease attacks the lungs (pulmonary TB). The bacteria spreads from one person to another through the air. When someone with active pulmonary TB coughs or even speaks, tiny droplets sent out from the lungs carry bacteria through the air. The droplets can easily be inhaled by others, especially in close contact. Common symptoms of pulmonary TB include chest pain, coughing—sometimes coughing up blood and mucus—and wheezing. People with active TB infection may also feel weak and have fever, chills or no appetite.

You might wonder what all this has to do with skin tests. Because active TB is so dangerous and because latent TB can develop into active disease, people who have a high risk of developing TB and their caregivers need to be tested for the disease. A small amount of solution containing an inactive part of the bacteria is injected under the skin. If the skin at the injection site doesn’t change, everything is fine. But if the skin becomes red or swollen, this indicates there are TB bacteria in the body and treatment is necessary.

Although the number of people infected in the U.S. has been steadily declining, more than 10 million people worldwide were sickened by TB in 2016. March 24 is World Tuberculosis Day. Learn more about how to stop the spread of TB.

Audrey Vasauskas

Curcumin, the Golden Spice

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Growing up, I enjoyed spending time in my grandmother’s kitchen. Her cooking usually involved an array of colorful spices, including a generous mix of curry powder in nearly every Indian recipe. You can’t mistake the tantalizing smell—cooking with this yellow-tinted powder can fill a room quite quickly. But it appears that there is much more to the aromatic spice than first meets the nose. It may help maintain heart health, too.

Turmeric, one of the spices that make up curry powder, contains curcumin. Evidence suggests that consuming curcumin has a wide range of physiological effects that may be beneficial to health. Curcumin is rich in antioxidants and acts as an anti-inflammatory, which may help explain its ability to promote nitric oxide (NO) availability. NO is a key compound in maintaining the health of our blood vessels. Scientists think that the body makes less NO and more becomes inactive as we age. Consequently, there is less available as we get older.

Also as we age, our blood vessels aren’t able to expand (dilate) as well. They become stiffer and less flexible and more likely to become clogged. Older people have a greater risk for developing high blood pressure due to the increased stiffness and reduced flexibility of the blood vessels. This process is called vascular aging. Women appear to experience vascular aging more quickly after menopause when the hormone estrogen is no longer produced.

A study of healthy middle-aged and older women in Japan found that taking curcumin supplements for eight weeks improved the blood vessels’ ability to dilate and reduced stiffening of the carotid artery in the neck. A recent study in the Journal of Applied Physiology found that exercise training alone does not protect against blood vessel stiffening in postmenopausal women. Therefore, combining exercise training with curcumin may be a promising way for women to slow down the steep decline in vascular health after menopause.

Another study of healthy middle-aged and older adults found that 12 weeks of curcumin supplementation improved NO availability and reduced oxidative stress (a type of cell damage) to improve blood vessel function.

These studies show promise for curcumin as a preventive therapy to lower heart disease risk in both men and women.

It seems that this golden spice really is a spice for life and may help prevent cardiovascular disease—the leading cause of death in the United States and worldwide—in older people.

March is National Nutrition Month. Learn more about how eating a balanced diet can improve your health at the Academy of Nutrition and Dietetics website.

Yasina Somani cropYasina 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.

Childhood Stress + Immune Overactivity = High Blood Pressure in Adulthood?

Portrait of little kid boy sad on birthday. child with lots of toy

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About 35 million adults in the U.S. may develop high blood pressure because of negative events that happened to them during childhood. Researchers are exploring how an event you experience when you’re a kid can cause high blood pressure as an adult.

About 35 million children in the U.S. experience early-life stress (ELS). ELS is any traumatic event that occurs for an extended period of time to a child younger than 10. These experiences may range from emotional, sexual or physical abuse to parental divorce or growing up in a low-income household. ELS often has negative health effects—including high blood pressure—throughout a person’s adult life.

High blood pressure occurs when the force of the blood passing through the blood vessels remains higher than normal. If the pressure is not controlled, the blood vessels become stiff over time, which reduces blood flow and oxygen to the heart and increases the risk of heart failure or heart attack. High blood pressure can also cause severe damage to blood vessels in the kidneys and may eventually lead to chronic kidney disease, a condition in which the kidneys are no longer able to filter blood to remove toxic waste from the body. People with severe chronic kidney disease require a treatment called dialysis to keep them alive. During dialysis, a machine removes waste and excess water from the blood, effectively acting as an artificial kidney outside the body.

Because of these potential complications, it’s important to understand how ELS puts people at risk for high blood pressure. Numerous studies have shown that activation of immune cells can make high blood pressure worse. A recent study explored how ELS affects the immune system in rat kidneys, the organs responsible for long-term blood pressure control. The study found that rats exposed to ELS had higher numbers of immune cell markers and more immune cell activation in their adult life. Prolonged immune cell activation can prevent the kidneys from working properly, which may cause high blood pressure later on.

Interestingly, the study also found that when the immune cells in the kidneys of ELS rats were stimulated they showed that the immune cells were overactive. This finding is important because it shows researchers are starting to understand more about the link between ELS and high blood pressure. However, more research is needed to fully establish a connection between childhood trauma, the immune response of the kidneys and high blood pressure in adulthood.

Ijeoma ObiIjeoma Obi, MS, is a PhD candidate in the University of Alabama at Birmingham’s Department of Medicine, Nephrology Division, Section of Cardio-Renal Physiology and Medicine.

Why Marriage Is Good for Your Heart

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Valentine’s Day is a time when many of us reflect on the importance of our closest relationships. Whether they include family, friends or a significant other, science is not silent on the impact these relationships have on our health. A review of 148 studies reveals that strong social relationships are associated with a 50 percent increased likelihood of survival, regardless of medical condition. Other studies link low social support to an increased risk and incidence of heart disease. The newest research, however, explores the effect our most intimate relationships—with a romantic partner—have on heart health.

A study that looked at more than 6,000 people reports that being single is associated with heart disease. Specifically, people who were single had a 45 percent higher rate of death from heart disease than those who were married. A striking finding in this study was that even though the reason for being unmarried varied among the participants—some people had never married, others were divorced, separated or widowed—the risks were consistently lower in married people. From these results, the overall benefit of the spousal relationship on heart health seems clear.

Many factors may account for the positive effect of marriage on heart health, including:

  • improved social support,
  • a less sedentary lifestyle, and
  • increased motivation to make healthy lifestyle changes.

The quality of marital relationships over time also influences heart disease risk factors. Men who described their relationships as “improving” had a lowering of risk factors compared to those in marriages categorized as “consistently good” or “deteriorating.”

In other words, marriage is generally good for your heart health and even better when you work to improve that relationship over time. So as you think about those closest to your heart on Valentine’s Day, do your heart a favor and take your sweetheart on a date.

Shawn Bender, PhD

Shawn Bender, PhD, is an assistant professor at the University of Missouri and a research health scientist at the Harry S. Truman Memorial Veterans’ Hospital.

Why Does Muscle Matter?

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When young people think about their muscles, they often focus on enhancing their muscle size and strength for cosmetic or athletic reasons. Those older than 50, however, need to be more concerned with just keeping the muscle they have. On average, people over the age of 50 lose 1 to 2 percent of their muscle mass each year, and after age 60, this number increases to 3 percent. Bed rest, lack of exercise and sedentary behavior in the elderly can speed up this gradual loss over time. Why is maintaining muscle so important for the elderly?

The simplest reason is that muscle is essential for all kinds of movement. Mobility is a crucial component of maintaining independence as we age. Adequate muscle mass and strength allow seniors to continue performing simple daily activities—things like bathing, getting dressed and preparing food—without assistance. Another less obvious reason is that muscle burns a large percentage of the energy that we get from the foods we eat. Losing muscle mass means that we do not use the energy from food as effectively, which can lead to chronic health conditions. In fact, loss of muscle mass is a major contributor to the increased rates of type 2 diabetes in older adults.

Current research has revealed, however, that muscle size is not the only, or even best measure of muscle health. Scientists have traditionally used the term “sarcopenia” to refer to aged-related loss of muscle mass, but many scientists are now focusing more on “dynapenia,” which indicates the loss of muscle function due to aging. New research is showing that how well muscle works can be just as important as how much muscle mass remains. In fact, a person with a smaller amount of muscle mass whose muscle function is good may be stronger and healthier than someone with more muscle mass but poor muscle function. This realization has led to new strategies for promoting muscle health in aging. Although maintaining muscle mass is still important, new approaches are targeting improvement in muscle function. These strategies go beyond simply lifting weights and look at ways to make the inner machinery of the muscle work better. Although nothing can completely stop the loss of muscle function with age, promising new nutritional and exercise therapies are emerging to substantially slow the decline, helping seniors stay active and independent for as long as possible.

Ben MillerBenjamin Miller, PhD, is an associate professor in the department of Health and Exercise Science at Colorado State University. He co-directs the Translational Research in Aging and Chronic Disease (TRACD) Laboratory.

2017’s 10 Most-read Posts

Using technology to take brainstorming to the next level

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Another physiology-filled year on the I Spy Physiology blog is almost over. This year, we’ve explored dozens of topics, ranging from skin cancer, gut health and spinal cord injury to the mystery of how hibernating animals’ muscles remain strong. We’ve celebrated women in science and smiled at the thought of turkeys running on treadmills. Today, we’re highlighting the 10 most-read posts of 2017.

Scholarly articles highlight the need for more research about women’s responses to illness and disease risk. In that vein, our most popular post this year looked at the relationship between sex-specific hormones and asthma. Posts about the danger of e-cigs—especially in the under-21 set—and how muscle rebuilds during the daunting feat of cycling the 500-mile Colorado Trail rounded out the top three. Take a look at this year’s top 10:

  1. When Hormones Take Your Breath Away
  2. The Trouble with E-Cigs: Why They May Pose More Harm than Good
  3. Muscle Rebuilding on the Colorado Trail
  4. Beer Does a Body Good?
  5. Meet Karyn Hamilton, Health and Exercise Science Professor
  6. Dog Gazing: Bond between Hound and Human
  7. Why Does Air Pollution Affect More Women than Men?
  8. When Vampires Attack: How Your Body Reacts to Extreme Blood Loss
  9. Microvesicles and Blood Vessels and Exercise, Oh My!
  10. The Hispanic Paradox: Why Are Some Ethnic Groups Living Longer than Others?

We’d love to hear what you’d like us to feature next year. Share your thoughts in the comments or send us an email. And don’t forget to follow our blog in 2018.

Erica Roth 

Look on the Bright Side—It May Improve Your Health

half full

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If you tend to see the proverbial glass as half empty instead of half full, you may want to rethink your position. Looking on the bright side and expecting good things to happen may have a positive effect on your physical health. An optimistic outlook on life may reduce your cardiovascular disease risk, lower blood pressure and improve overall health and longevity. It can also reduce sensitivity to pain and may help people manage chronic pain more easily.

You may be skeptical or cautiously optimistic about this. How can simple optimism lead to good health? The answer is still not entirely clear, but scientists are slowly uncovering the biological details. They’ve learned that the body’s response to stress may be an important factor.

When the body is stressed, it sends biological messengers called stress hormones into the bloodstream to tell different organs to respond in various ways. One of the major stress hormones is cortisol. When cortisol is high, the body responds by making unhealthy amounts of certain substances (such as cholesterol) that can harm the heart. These substances may damage and cause inflammation in the blood vessels. Inflammation may also lead to more damage in the circulatory system. This unfavorable chain of events may increase the risk of heart disease.

People who look on the bright side may be more likely to have markers of good health—including lower stress hormone levels—even when they face stressful situations. One study found rats with pessimistic behavior traits had more inflammation than their optimistic counterparts. Lower cortisol and inflammation levels may be due to decreased activity of the fight-or-flight nervous response, although more research is needed.

Motivation may also play a role in boosting the health of optimists. People who think positively may be more motivated and tend to make more of an effort in social interactions than those who are pessimistic. This can lead to healthier social connections and an increase in beneficial behaviors such as exercising regularly and following a healthy diet. The motivational aspects of optimism (or pessimism) may also affect a person’s behavioral response to stress.

December 21 is “Look on the bright side” day. Try a visualization exercise to boost your optimism. It may have a positive effect on your overall health.

Audrey Vasauskas

Exploring Causes and New Treatments for Sickle Cell Disease

genemarker

Shaina Willen, MD, of Vanderbilt University Medical Center, presents her poster at the Physiological and Pathophysiological Consequences of Sickle Cell Disease conference.

Sickle cell disease (SCD) is a lifelong disorder of the red blood cells. It’s caused by a mutation in a single gene and affects about 100,000 people in the U.S. Normal red blood cells are round, a shape that helps the cells carry oxygen around the body. But red blood cells in people with SCD can become abnormally shaped like a crescent (sickle), which can cause blood cells to get stuck in blood vessels and interfere with blood flow, leading to severe pain.

Scientists and medical doctors who specialize in SCD gathered last month in Washington, D.C., for the American Physiological Society conference “Physiological and Pathophysiological Consequences of Sickle Cell Disease.” They discussed new research into the causes of the disease and new therapies that can treat and even prevent SCD-related pain episodes. Read on to learn more about their findings.

Certain patients with SCD may have a higher risk than others of developing complications—such as increased pain, stroke, eye problems and kidney disease—but finding out which patients have a higher risk is challenging. New research from Vanderbilt University Medical Center has uncovered a genetic marker that may be able to identify which patients are more likely to have these complications.

Emotional stress is known to trigger or worsen physical symptoms of disease, including some types of pain. A group of researchers from California found that stress and the anticipation of pain causes blood vessels to become narrower (vasoconstriction). In people with SCD, vasoconstriction can be dangerous because abnormally shaped (sickled) cells may be more likely to get stuck in the blood vessels and block blood flow.

A healthy digestive system is typically filled with various types of bacteria that aid in digestion. However, researchers from Howard University found that people with SCD are more likely to have higher levels of one specific bacterium, Veillonella. Veillonella link together to form a film in the digestive tract, which can attract red blood cells. When red blood cells stick to the film, it can block blood flow to the rest of the body, which causes increased pain. This discovery may help scientists find a way to rebalance gut bacteria levels and reduce symptoms.

These studies are just a few examples of the high-caliber SCD research being done. Read more highlights from this year’s conference:

Alzheimer’s drugs may improve red blood cell function and quality of life

Scientists explore ways to create red blood cells outside the body and prevent sickling

Erica Roth 

The Trouble with E-Cigs: Why They May Pose More Harm than Good

E-Cigs

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The market for electronic cigarettes (e-cigs) and vaping has surged in popularity within the past five years, while traditional cigarette sales have declined. From 2012 to 2013, e-cig sales more than doubled to $1.7 billion. By 2015, sales were estimated at $3.7 billion.

Although manufacturers claim that e-cigs are safer than traditional cigarettes, their use has been associated with clear health risks. E-cigs may seem like they are producing harmless water vapor, but that vapor has been shown to contain a mix of cancer-causing chemicals. Some of the toxin levels are comparable to those in cigarettes.

E-cigs are associated with cellular damage and decreased cough reflex sensitivity after just one use. Cough reflex—triggered by chemical or mechanical irritants—protects the upper respiratory system from infection by getting rid of respiratory secretions (mucus) and foreign material from the lungs. Decreased cough reflex sensitivity may increase the risk of infection because mucus and foreign material aren’t always cleared immediately from the airways. Studies on animals have found that nicotine-containing e-cig fluid may cause changes in the lungs similar to what humans experience with chronic obstructive pulmonary disease (COPD). COPD is a condition often seen in long-term smokers. These changes include narrowing of the airways, more mucus production and increased inflammation. E-cig vapor has also been linked to substantial DNA damage and increased cancer risk and decreased lung function.

no smoking no vaping sign ban cigarette and electronic cigarette not allowed blue e-cigarette and cigarette in red circle realistic vector illustration

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More and more research is providing evidence that e-cigs pose serious health risks. One of the greatest concerns is the potential serious long-term consequences in teenagers. Teens are easy targets for tobacco and e-cig advertisers and may also be easily swayed into becoming lifelong tobacco users. Because of the potential health risks of e-cigs, the American Academy of Pediatrics recommends raising the legal purchasing age for both traditional cigarettes and e-cigs from 18 to 21. Marketing strategies of e-cigs try to make e-cigs look socially acceptable to young adults and teens by promoting candy-inspired flavors and vapor tricks on social media. The tendency for the e-cig market to prey on young adult consumers is particularly troubling because the brain is developing critical circuitry that relates to lifelong habits during this time. Users younger than 21 tend to remain nicotine users for life.

The Great American Smokeout sponsored by the American Cancer Society, is November 16. This event is designed to help smokers make a plan to quit, whether it’s traditional tobacco products or e-cigs. Their health depends on it.

 

Leigh Graziano croppedLeigh Graziano, MS, is a second-year medical student at the Alabama College of Osteopathic Medicine. She works with Audrey Vasauskas, PhD, on research on pulmonary arterial hypertension, which is high blood pressure in your lungs. In her free time, Leigh enjoys yoga, mountain biking and fishing.

The Hispanic Paradox: Why Are Some Ethnic Groups Living Longer than Others?

Senior couple smiling together

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In the U.S., we focus much attention on the health behaviors that can help us live a longer life: the “secrets” of centenarians and long-lived animal species such as the naked mole rat, the optimal amount of exercise to help us maintain muscle tone and independence, and the best eating style—whether it’s eating like we live in the Mediterranean, restricting calories or something in between. Yet part of the U.S. population seems to be unlocking the keys to increased longevity despite having risk factors traditionally linked to a shorter lifespan.

Approximately 55 million people in the U.S. are of Hispanic descent, and on average, they live two years longer than non-Hispanic whites. The Hispanic population in the U.S. has a lower overall risk of dying from 7 of the top 10 leading causes of death, including cancer and heart disease. Known as the “Hispanic paradox,” these positive health outcomes are often achieved among immigrant populations and in people with a greater likelihood living in poverty, having less education and health insurance, being overweight and several other factors that can negatively affect health. Additionally, rates of illness and death from other chronic conditions such as diabetes and liver disease remain higher among Hispanics than whites.

In an effort to boost longevity across ethnicities, scientists are studying how these unlikely circumstances—being high risk in certain areas, yet having a longer lifespan—can coexist. Theories include:

  • A study of lung disease in Hispanics suggests that their genes may protect against chronic obstructive pulmonary disease (COPD), an inflammatory lung disease, in addition to other factors.
  • Hispanics who come to live in the U.S. are generally younger than the average population and stay healthier.
  • With the exception of people from Puerto Rico, immigrants from Hispanic cultures smoke less than the overall population, leading to less lung disease. One study found that Hispanics in New Mexico are diagnosed less often with COPD than those living in other areas. Puerto Ricans, however, tend to smoke more and have a higher asthma risk.
  • A diet rich in beans and lentils, common in some Hispanic cultures, may curb inflammation to reduce chronic health risks.
  • Researchers think the strong family ties and support system seen in extended Hispanic families may play a role in staying healthy, particularly in the area of mental health.

Researchers continue to study Hispanic populations in the U.S. to try to find concrete reasons behind the Hispanic paradox to help them live even longer, healthier lives. During National Hispanic Heritage Month, we celebrate Hispanic heritage and culture in the U.S.—and all that these communities can teach us about living a healthier and longer life!

Erica Roth and Stacy Brooks