Life Lines - The Podcast of The American Physiological Society

APS’ Chief Science Officer Dennis Brown, PhD, recently spoke to astronaut and APS member Jessica Meir, PhD, about her work on the International Space Station. As part of the interview, we asked her for lessons that #StationLife can teach us about living in isolation. Listen to her recommendations and read the full interview in the July issue of The Physiologist Magazine.

From the cutting room floor, here are some of the outtakes about physiology that we thought were just too interesting not to use: 1.    Dusty Sarazan describes one way that physiological research helped advance cardiac surgery, and also how research led to the development of the modern treadmill 2.    David Linden talks about our imperfect memories 3.    David Kraus tells us why we are so sensitive to the odor of hydrogen sulfide gas (what is hydrogen sulfide gas? where does it come from and what does it do?).

Heart attacks peak during the winter months and cold weather has been thought to be the primary culprit. But cardiologist Robert Kloner of the Keck School of Medicine and Good Samaritan Hospital found that heart attack deaths peak on Christmas and New Year's in the mild climate of Los Angeles County. Could it be that the weather is not the most important factor behind the seasonal increase in heart attacks? The show's second segment, the Buzz in Physiology, features research on how a probiotic treatment alleviated colitis in mice and how five exercises helped women office workers suffering from repetitive strain injury. (Begins at 10:55) From the American Heart Association, Heart Attack/Stroke Warning Signs. Click here. Total Time: 13:28

What would it be like to live without being able to detect any odors? For one thing, Thanksgiving would be much less enjoyable, perhaps disturbingly so. In this episode, we talk to Robert I. Henkin of the Taste and Smell Clinic in Washington, D.C., who will tell us why people lose their sense of smell and how his research can help some people restore it. (Begins at: 02:03) The Buzz in Physiology features studies on a simple test that may determine arterial stiffness in adults older than 40, and a look at a 1950s program that tested the fitness of women to become astronauts. (Begins at: 00:43)

Dean Franklin developed the first instruments to measure blood flow and the changes in diameter of the pulsating heart in conscious animals. He also pioneered the use of radio waves to measure heart and blood vessel function without wiring the body to the instrument. Dusty Sarazan, a former student of Dean Franklin, explains how these inventions led to the non-invasive cardiovascular monitoring instruments we have today. You can find the full article on Dean Franklin here and a press release here. (Begins at 02:22) A program note: We misspoke when we mentioned that physiologists made an important discovery after a giraffe frightened an instrumented baboon. In fact, a leopard had frightened the baboon. The Buzz in Physiology (Begins at 00:52) A study on how exercise helps prevent weight regain after dieting finds that exercise reduces the drive to overeat, causes the body to burn fat before burning carbohydrates and prevents an increase in the number of fat cells during weight regain. A study on how alcohol can disrupt circadian rhythm finds that chronic drinking blunts the biological clock's ability to synchronize daily activities to light, disrupts natural activity patterns and continues to affect the body's clock even days after the drinking ends.

You've heard the word telecomm? In this episode, we are going to coin a new word: elecomm, shorthand for elephant communication. Caitlin O'Connell-Rodwell is a Stanford University professor and the author of The Elephant's Secret Sense, published by the University of Chicago Press. Dr. O'Connell-Rodwell discovered that elephant vocalizations travel through the ground, sometimes for great distances. Other elephants pick up these seismic communications and understand them. There are links to videos of three of Dr. O'Connell-Rodwell's elephant communication experiments on her website, www.utopiascientific.org or by clicking here, here and here. (Begins at 2:44) From the Buzz in Physiology (Begins at 1:13): Divers who held their breath for several minutes had elevated levels of S100B (a protein found after cell injury) in their bloodstream, which suggests that holding one's breath for a long time disrupts the blood-brain barrier. However, the appearance of the protein was transient and leaves open the question of whether lengthy breath holding can damage the brain over the long term, according to the Lund University researchers. And drinking beetroot juice boosts stamina and could help you exercise for up to 16% longer, according to a study from the University of Exeter. The study shows how the nitrate contained in the juice leads to a reduction in oxygen uptake, making exercise less tiring. You can read the press releases on these studies: Freediving Beetroot

Episode 24: Pregnancy and Exercise When a pregnant woman exercises, is it good for her fetus? That is the question that researchers Linda May of the Kansas City University of Medicine and Biosciences and Kathleen Gustafson of the University of Kansas Medical Center are trying to answer. Their work is ongoing, but it is good news, so far, for pregnant women who like to exercise. (Begins at 01:59) Buzz in Physiology (Begins at 00:47) Estrogen can halt the damage caused by a stroke by inactivating the protein, p53.  Researchers have found a way to diagnose overtraining syndrome in horses by measuring the secretion of nocturnal growth hormone. 

Three physiologists tell us why the prescription "drink when you are thirsty" is usually the best guideline for deciding when and how much to drink. We will talk to Heinz Valtin of Dartmouth Medical School (retired); Mark Knepper, the chief of the Laboratory of Kidney & Electrolyte Metabolism of the National Heart Lung and Blood Institute; and Samuel Cheuvront, of the Thermal and Mountain Medicine Division of the U.S. Army Research Institute of Environmental Medicine about water consumption. They will answer the question: "Must I drink 64 ounces of water each day?" (Begins at 3:47) To read the review of the eight-by-eight rule by Heinz Valtin, click here: In the Buzz in Physiology, we look at studies involving a prosthetic device known as the Cheetah Flex Foot and whether it gives a runner who is a bilateral amputee an unfair advantage over limb-intact runners. We also summarize a study in mice in which adult bone marrow stem cells were used as a non-invasive therapy to repair cardiac tissue. And finally, we'll look at a study that finds that electro-acupuncture successfully reduced sympathetic nerve activity, normalized menstrual cycles and reduced testosterone in women with polycystic ovarian syndrome. (Begins at 1:05)

There is nothing like a good laugh, is there? It not only feels great to laugh, it can feel great to hear other people laugh. Beyond brightening the mood, can laughter provide tangible health benefits? Lee Berk of Loma Linda University in California has done a series of studies on laughter and its possible physiological effects. We will talk to him about his latest study, done over the course of a year with diabetic patients. (Begins at 3:50) In this month’s Buzz in Physiology (begins at 0:51), we look at studies that provide possible explanations for: Why pregnant Andean give birth to larger babies at high altitude, compared to European women How certain side effects in some medical procedures may trace back to a solvent found in plastic tubing Total Time: 9:47

Did you know that there is a sensor in the nerve endings in the carotid artery that rapidly lowers blood pressure when stimulated? This discovery may one day allow people who are hypertensive to lower their blood pressure by using a pacemaker-like device that stimulates the nerve endings in the blood vessels. In this edition of Life Lines, we talk to Francois Abboud, of the Carver College of Medicine at the University of Iowa whose research identified this sensor. We’ll also talk to him about his recent research looking at the genes that regulate ion channels, microscopic gates that move chemicals in and out of cells, and that play a role in the signaling between the brain and the blood vessels. In experiments with animals, Dr. Abboud and his colleagues deleted one specific ion channel and found that the animals developed high blood pressure. (Begins at 03:51) We'll also talk to Ann M. Schreihofer, of the Medical College of Georgia, who focuses on the role the brain plays in increasing sympathetic nervous activity, which contributes to many forms of hypertension (high blood pressure). Among the questions her research seeks to answer is why people who are obese become hypertensive. The Schreihofer laboratory has also been looking at sleep apnea and whether it is possible to improve respiratory function as a way to reduce the sympathetic activity that leads to obesity and hypertension. (Begins at 09:43) In the Buzz in Physiology (begins at 1:24), we have studies on: resistance training and octogenarians muscle atrophy during lengthy space missions belly fat, inflammation and exercise The photo in our logo is a neuron from the rostral ventral lateral medulla of the brain stem and was provided by Dr. Schreihofer. Total running time: 16:45.

Celiac Update. Celiac disease is an uncontrolled immune response to wheat gluten and similar proteins of rye and barley. In those who have celiac disease, gluten can damage the small intestine, inhibit nutritional uptake and lead to malnutrition. Among the symptoms are diarrhea, stomach pain, fatigue, weight loss and slow growth. One study estimated that 1 in 133 people in the U.S. population have celiac disease. Many people do not know they have it, sometimes because there are no symptoms. Because celiac disease has a genetic component, there can be a much higher prevalence of the disease within families. Three years ago, a group of Dutch researchers led by Frits Koning of the Leiden University Medical Center published a study on an enzyme that showed promise as a treatment for celiac disease. The enzyme, prolyl endoprotease, or PEP, could quickly break down gluten in the stomach before it ever reached the small intestine, where it causes damage. In this episode, we ask Frits Koning to update us on his research. (Begins at 2:45) Total Time:  11:20

Have you ever had an experience like this: You and a friend start jogging together. Neither of you have been exercising much, but after a few days, your friend is easily striding along as you wheeze, gasp and hold onto your aching side. Do not feel bad about your performance; it may be your genes. Scientists have identified about 200 genes that play a role in our body's ability to become fitter, referred to as "adaptation to exercise." In this episode, we talk to Mark Olfert of the University of California at San Diego and Claude Bouchard of the Pennington Biomedical Research Center. They have organized a symposium on the genetics of adaptation to exercise, to take place at the Experimental Biology conference in New Orleans in April. They will give us a flavor for the research in this field by telling us a bit about their own work. (Begins at 3:51) In the Buzz in Physiology (Begins at 1:21) University of Illinois researchers are developing a program to train people to avoid falls. This research could be particularly valuable for the elderly, for whom falling can be an especially dangerous proposition. And a study from the University College London Medical School sheds light on why patients with cirrhosis may have a more regular heart rhythm than is normal, and why they develop hepatic encephalopathy, a neurological disorder. The body's inflammatory response may be the common thread behind the development of these conditions. 

Lucy Brown, a neuroscientist at the Albert Einstein School of Medicine, has studied romantic love using functional magnetic resonance imaging. Dr. Brown will talk about her studies on what happens in our brains at different stages of love: falling in love, being rejected by a lover, and longterm love.  Obstructive sleep apnea is the most commonly diagnosed condition among sleep-related breathing disorders and can lead to debilitating and sometimes fatal consequences for the 18 million Americans who have been diagnosed with the disorder. 

Accumulating evidence indicates that an increase in particulate air pollution is associated with an increase in heart attacks and deaths. In this episode, we'll talk to Aruni Bhatnagar of the University of Louisville and Robert Brook of the University of Michigan about research in the relatively new field of environmental cardiology. This field examines the relationship between air pollution and heart disease. (Begins at 2:58) Research update: Dr. Brook published his study in the September, 2009 issue of the journal Hypertension, a publication of the American Heart Association.   Why was the man known in scientific literature only as "H.M." so important to neuroscience? David Linden of Johns Hopkins University explains why in the wake of H.M.'s recent death. (Begins at 14:54) The Buzz in Physiology: (Begins at 1:14) A new study with rats could help uncover how we get hooked on sugary food.   The heart's beat is not a simple in-and-out movement, but has a bit of a twist to it. Researchers have created images showing the connection between the configuration of the heart's muscular layer and how the heart contracts. The study is available here. Be sure to click on the supplemental video to see how it works.

We’ll start this episode by talking about clocks, but not the type of clock that ticks away on your wall. Instead, we’ll talk about the biological clocks that tick inside us. Clifford Saper of the Beth Israel Deaconness Medical Center in Boston will explain some of the research on circadian rhythm and will share his theory about the best way to deal with the disruption of the biological clock caused by jet travel. If you’re traveling this holiday season, or anytime in the near future, give a listen. (Begins at 3:14) Do you have a tendency to overeat during the holidays? A new study finds that exercise affects the release of two hormones that help regulate appetite, ghrelin and peptide YY. This may help explain why exercise is often, even if only briefly, associated with suppression of appetite. David Stensel of Loughborough University in the United Kingdom will talk about his study, which appears in the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology. (Begins at 11:54) Total Time: 20:27