Dog Gazing: Attachment between Hound and Human

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While walking through Santiago, Chile, you are likely to come across at least one of the countless wandering dogs that live on the busy streets. Homeless dogs are a normal part of Santiago’s culture. They are quick to make friends with anyone who offers a welcoming hand or food. They are not quick, however, to forget their friends. If you make a canine companion in this city, as my classmates and I did, it will probably remember you the next time you come down the street.

The feeling of attachment between the dogs and people of Santiago reminded me of the way a mother and her infant gaze into each other’s eyes. This simple, mutual act of love causes an automatic reaction in both the mom and baby, which increases the levels of oxytocin in the body. Oxytocin is a hormone that plays a major role in social bonding between mothers and infants and between romantic partners. The release of oxytocin promotes a feeling of social well-being and may prevent stress. Interacting with the local dogs in Chile made me wonder if this same sense of happiness and bonding occurs between dogs and people.

A research study looking at the bond between humans and dogs found a similar release—and increase—of oxytocin during social interactions, such as gazing, in both the animals and people. The dogs’ hormone levels also increased when people talked to and petted them. Scientists think this looped interaction reaction (bonding in both directions between pooch and person) may be a reason that humans were able to domesticate wild dogs in the first place. Dogs are one of the only animals known to fully recognize human facial features and expressions. This ability likely helps dogs and people communicate, love and take comfort in one another’s presence.

This mutual interaction is likely the cause of a quick, yet memorable, friendship between humans and dogs both at home and in places like the streets of Santiago. So next time you see a dog in passing, don’t be afraid to gaze into its eyes and form a quick friendship.

 

goff black white dogLogan Goff is an exercise physiology major at the University of Dayton. Anne R. Crecelius, PhD, is an assistant professor in the Health and Sport Science Department at the University of Dayton. They spent four weeks in Chile as part of a study abroad program in partnership with the Universidad de los Andes studying nutrition, sports and research in the context of the Chilean culture. This is the final installment in a three-part series (read part one and part two) that spies physiology in this dynamic South American country.  

 

 

 

When Hormones Take Your Breath Away

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After a healthy childhood, my best friend suddenly started having breathing difficulties when she was 20 years old. The doctor diagnosed her with asthma. With the help of inhaled medications, she was able to control her symptoms. But a year later, the medications were no longer effective and she started having monthly, life-threatening asthma attacks. The severe attacks became more frequent a few days before her menstrual period, and the symptoms disappeared days after her period ended. At that time, I wondered if hormones could be to blame.

As a graduate student investigating the role of male and female hormones in lung inflammation, I know now that asthma can be a hormone-related health issue. Unfortunately, many people are unaware of this relationship. Hormones are chemicals that travel as messengers around the body through the bloodstream. They affect many bodily functions and play a large role in a woman’s life cycle from birth through puberty, adulthood, pregnancy and menopause. In proper balance, hormones help the body communicate and thrive. But sometimes hormone levels can be too high or too low, causing serious health problems, especially in people with asthma.

Although more young boys have asthma than girls, the pattern is reversed in adults: More women have asthma than men. During puberty girls begin to produce higher levels of the sex hormones estrogen and progesterone, which rise and fall throughout their menstrual cycle. About one-third of females with asthma report premenstrual-related asthma symptoms, which may lead to severe attacks. A research study of girls ages 8 to 17 found that those who started menstruating at earlier ages developed more severe asthma after puberty, perhaps because their hormone levels began to change earlier in life. Studies have shown that hormonal changes can disturb the airways and inflammatory responses in the lungs. As hormone levels go up and down, new blood vessels in the lungs form and disappear, affecting the lungs’ ability to take in oxygen. In addition, female hormones do not just cause breathing problems in women with asthma, but also in those who smoke or are overweight.

Researchers are working to discover how sex hormones affect the lungs in order to develop personalized treatments for asthma. Ideally, specialized treatments in the future will be gender-specific and take into consideration a person’s hormonal status.

Nathalie Fuentes OrtizNathalie Fuentes is a PhD candidate in the biomedical sciences program at Penn State College of Medicine. Her studies in Dr. Patricia Silveyra’s lab include the development of sex-specific therapies to treat lung diseases, sex differences in asthma-related lung inflammation triggered by ground-level ozone and the role of male and female sex hormones in lung disease. Nathalie is originally from Caguas, Puerto Rico.

 

 

Fact or Fiction: Does Coca Candy Prevent Altitude Sickness?

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This summer, I spent a month studying at the Universidad de los Andes in Chile. We visited the Atacama Desert, the driest non-polar desert in the world. It is nestled between two sets of mountains; during one of our excursions we hiked up the Andes Mountains to a village called Socaire, located at an altitude of around 11,000 feet above sea level.

Our site coordinator, physiology professor and “temporary mom,” Anne Crecelius, PhD, kindly offered us coca candy, hoping it might prevent the dizziness, nausea and headaches sometimes associated with altitude sickness. She had asked us to drink more water than we usually do, too, just in case anyone in our group responded badly to being so high up. Coca candy is made in part from coca leaves, a plant that local people have chewed on for thousands of years. Coca leaves contain chemical compounds called alkaloids, which have been shown to reduce hunger and calm the side effects of high-altitude travel.

The question remains whether coca really has physiological benefits. The research is mixed. Some studies, citing the uses of coca throughout history, claim that there are significant benefits to chewing coca leaves. They recount improved energy efficiency during exercise, boosted energy levels—similar to the effect of caffeine in coffee—and decreased thirst and appetite.

However, other researchers suggest that the effects of coca leaves are mostly psychological, similar to a placebo effect (using a fake treatment, or placebo, in a group of people to compare the effects with people using a real treatment). In some cases, the group taking the placebo will also see improvement in their condition.

Even if coca leaves do prevent altitude sickness symptoms, the candies we munched on did not contain enough coca to help much. But perhaps they were enough to create some sort of placebo effect in our group, as no one was sick, just a little out of breath. Nevertheless, we enjoyed the town, the candy and a snowball fight near a very old church. Who knew that a small town at high altitude could be so much fun? Most likely, the locals and generations of indigenous people, who also know of the power of coca.

Andrew KramerAndrew Kramer is an exercise physiology major at the University of Dayton. Anne R. Crecelius, PhD, is an assistant professor in the Health and Sport Science Department at the University of Dayton. They spent four weeks in Chile as part of a study abroad program in partnership with the Universidad de los Andes, studying nutrition, sports and research in the context of the Chilean culture. This is the second in a three-part series that spies physiology in this dynamic South American country. Read part one.

 

Being Left (Handed) Is All Right

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“There’s something I ought to tell you. I’m not left-handed either.” – Westley, The Princess Bride

Throughout history, left-handedness has both fascinated and frightened people. Maybe it is because only about 15 percent of the population is left-handed. Or maybe it is because the reasons for left-handedness remain somewhat of a mystery.

What makes a person left- or right-handed? It seems we can find the answer in our genes, at least partially. Most researchers in the field agree that left- or right-handedness is most likely produced by genetic influences. We inherit our genes from our parents, and the genes that are turned on determine our characteristics. The specific reasons behind these genetic differences are still hotly debated, but many studies seem to point to natural selection as a probable cause.

The human brain is divided into the right and left hemispheres, with nerve fibers connecting the two. Different parts of each half of the brain control different functions of the body. Many evolutionary biologists argue that evolution produced a majority of people who controlled language with their left brain, which also controls the right side of the body, including the right hand. As written language developed, people with genes toward right-handedness had a genetic advantage and passed those genes down to their children. But the question remains: Why are some people left-handed when natural selection seems to be evolutionarily “against” left-handedness?

Scientists have discovered that handedness is influenced by not just one, but a group of genes, and that these genes can be influenced by external and societal pressures. For example, if a person expresses the genes for left-handedness, they may be taught to write with their right hand. In the same way, a person who writes with their right hand can be taught to use their left hand to throw or shoot a ball for a competitive advantage.

Although it may be more difficult to find a pair of scissors or spiral notebook that are easy to use, left-handedness has its advantages. Left-handers have been shown to have greater coordination, and left-handedness has been linked to creativity, especially in men. This may be due to the connection with the right brain, which is the creative hemisphere. Many lefties excel in sports such as tennis and fencing, possibly because there are fewer left-handed opponents.

While research continues into what makes left-handed people unique, we can celebrate our left-handed friends now in honor of Lefthanders Day on August 13.

Audrey Vasauskas

Beer Does a Body Good?

Drinks: Beer Isolated on White Background

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Bone is a living organ that constantly breaks down and rebuilds itself. As we get older, bone breaks down more and rebuilds less, which often leads to weaker bones over time. If we lose too much bone, we increase our risk of fracture and developing osteoporosis.

Women tend to have weaker bones and a faster rate of bone loss—particularly after menopause—than men. Approximately 50 percent of women in the U.S. over the age of 50 will break a bone due to osteoporosis. If the broken bone is in the hip, there is about a 20 percent chance that the individual will die within one year. Breaking a bone in our later years can significantly affect quality of life and the ability to live independently. Therefore, it is important to do everything we can to minimize age-related bone loss.

Lifestyle choices can help minimize bone loss, including:

  • following a healthy diet with enough calcium and vitamin D;
  • participating in regular physical activity; and
  • refraining from smoking.

Believe it or not, drinking a beer now and then may even help.

Researchers in Spain have discovered a link between beer consumption and bone health in women. They found that women who drank moderate amounts of beer—defined in the U.S. as up to one 12-ounce beer per day—had stronger bones than those who did not.

Beer contains two important nutrients that could be beneficial to bone health: phytoestrogens and silicon. Phytoestrogens are naturally occurring nutrients in plants that act similar to the hormone estrogen. Estrogen protects women from bone loss, but levels drop significantly after menopause. Estrogen deficiency is the primary cause of bone loss after menopause. Silicon is a naturally occurring mineral that may be used as a supplement to reduce bone breakdown and increase bone rebuilding in women with osteoporosis. Beer is one of the most plentiful sources of silicon in the Western diet.

It’s likely that the combination of phytoestrogen and silicon in beer helps limit bone loss. This finding has potentially important implications for bone health, although more study is needed.

It is also important to remember that drinking too much alcohol has many negative health effects, including reduced bone strength. Keep beer intake at a moderate level. That said Aug. 4 is International Beer Day. Drink a toast to healthy bones!

 

Kim HenigeKim Henige, EdD, CSCS, ACSM EP-C, is an associate professor and undergraduate program coordinator in the department of kinesiology at California State University, Northridge.