Sci-Ed Update 259

A TAPP slowdown, Beethoven's DNA, penile microbiome, dropping life expectancy in U.S., exercise doesn't change calories used and much more!

Mar 28, 2023

Temporary Slowdown at TAPP

Perhaps you noticed the slowdown—or should I say shutdown?—at The A&P Professor (TAPP) this past week. No issues of this newsletter were sent out and the expected new episode of the TAPP podcast did not drop last week.

I apologize.

As you probably realize, these projects are a labor of love and the considerable work it takes to produce them is done in-between my “real” jobs—two teaching gigs and writing several A&P textbooks. So when disaster strikes, there’s really no guess as to what comes last on my priority list.

I’m the primary healthcare wrangler for several relatives who are currently struggling with life-threatening crises. So, between hospital and rehab transfers, conferences with providers and insurers, conferences with bankers and attorneys, calls and visits, and even using my lion taming skills to temporarily integrate a wild animal (chihuahua mix) into our home menagerie while her person tries to hang on, I’m kinda drowning here.

If you’ve been in this situation, you know. Right?

So here’s a fresh newsletter issue to tide us over until I can do the next one. And I’ll be trying to do the post-production on a great chat I had on uncertainty (a timely topic for me, to be sure) with Dr. Michelle Lazarus for the next podcast episode. But in the meantime, I’m working on being grateful for the opportunity to help my relatives in their time of need.

Your native language may shape the wiring of your brain

The connections between different regions of the brain responsible for language processing depend on which language you grew up with.

The observed differences in these language network structures were related to linguistic characteristics in the native languages of the study participants: German and Arabic.
"So the difference we find there shouldn't be due to different ethnic background but really because of the language we [they] speak," Alfred Anwander(opens in new tab), a researcher at the Max Planck Institute for Human Cognitive and Brain Sciences in Germany who led the study, told Live Science. The research was published online in February in the journal NeuroImage(opens in new tab).

'Live free and die?' The sad state of U.S. life expectancy

Life expectancy continues to decline in the U.S. as it rebounds in other countries

Just before Christmas, federal health officials confirmed life expectancy in America had dropped for a nearly unprecedented second year in a row – down to 76 years. While countries all over the world saw life expectancy rebound during the second year of the pandemic after the arrival of vaccines, the U.S. did not.
Then, last week, more bad news: Maternal mortality in the U.S. reached a high in 2021. Also, a paper in the Journal of the American Medical Association found rising mortality rates among U.S. children and adolescents.
"This is the first time in my career that I've ever seen [an increase in pediatric mortality] – it's always been declining in the United States for as long as I can remember," says the JAMA paper's lead author Steven Woolf, director emeritus of the Center on Society and Health at Virginia Commonwealth University. "Now, it's increasing at a magnitude that has not occurred at least for half a century."
Across the lifespan, and across every demographic group, Americans die at younger ages than their counterparts in other wealthy nations.
How could this happen? In a country that prides itself on scientific excellence and innovation, and spends an incredible amount of money on health care, the population keeps dying at younger and younger ages.

Beethoven’s DNA decoded from locks of hair saved by his fans

A tuft of hair believed to belong to German composer Ludwig van Beethoven, known as the Stumpff lock, is studied at the Max Planck Institute for the Science of Human History. (Anthi Tiliakou)

In 1802, German composer Ludwig van Beethoven wrote a heart-wrenching letter to his brothers, describing the deafness that forced him to “live like an exile” and yearn for death. Beethoven kept going for another 25 years, propelled by his music, but he begged them to have his hearing loss studied and publicized, so that “so far as possible, the world may be reconciled to me after my death.”
Two centuries later, a team of international researchers has answered that plea by sequencing Beethoven’s DNA, preserved in locks of his hair that collaborators and fans collected as treasured keepsakes.
The central ailment of Beethoven’s life was his hearing loss, which began in his mid-20s. He also suffered from debilitating gastrointestinal symptoms and attacks of jaundice. An autopsy revealed that he had cirrhosis of the liver, pancreatitis and a swollen spleen. Medical biographers have debated what killed him at the age of 56 and whether his liver disease was the result of excessive drinking or some other cause.

Why doing more exercise won't help you burn more calories

Forget the idea that to lose weight you just need to work off more calories than you consume. The truth is far weirder

A SIMPLE calculation lies at the heart of a lot of mainstream weight loss advice. If calories out exceed calories in, you will lose weight. It is why both exercise and diet are said to be key to staying trim, and why many of us feel we can make amends for overindulging by joining the gym or dusting off our running shoes.
But if you have ever increased how much exercise you do and found it did little to shed the pounds, you have probably had an inkling that the sums don’t add up. Despite tipping the balance in favour of calories out, the scales don’t budge. This is the so-called exercise paradox. Until recently, it has been explained away by the logic that exercise leaves people hungry so they eat more.
It now turns out something weirder is going on. Working out a lot doesn’t appear to burn more calories than doing a little. In fact, going mad in the gym doesn’t seem to burn any more calories than moderate activity a few days a week and taking the stairs, for instance.

Humans Walk Weird. Scientists May Finally Know Why

Humanity’s peculiar gait has long confounded engineers and biomechanists—but it might be one of nature’s clever tricks.

Image: MEIK WORPUS/Getty Images

FOR SOMETHING SO routine, walking is shockingly complicated. Biomechanists break a single step into several phases: First there’s touchdown, when your heel strikes the floor. Next comes the single support phase, when you’re balancing on that leg. After that, you roll onto your toes for takeoff and your leg goes into a forward swing.
All of this contains a mystery. Researchers have long observed that when we walk, our planted leg bounces twice before swinging into the next step. That is, the knee bends and extends once when the foot first touches down, then again just before takeoff. That first bounce helps our foot absorb the impact of our weight as we hit the ground. But the function of the second bounce, a feature characteristic to human gait, has never been clear.
In a Physical Review E paper published last month, scientists at the University of Munich may have found an answer. By modeling the physical forces that drive our double bounce, they deduced that it’s an energy-saving technique for a species that has long prioritized endurance over speed—which may be a clue about why humans evolved such an odd gait. Now, they think their model can help improve prosthetic and robotic designs, and may even lend insight into the evolutionary pressures our ancestors faced.

The microbiome inside the penis can be altered by vaginal sex

The penis plays host to a collection of bacteria known as the penile microbiome, and an analysis of urethral swabs has found that men who have vaginal sex can pick up bacteria normally found in the vagina

A transmission electron micrograph of a colony of Gardnerella vaginalis, bacteria that are found in vaginas and the urethras of men who have vaginal sex MOREDUN ANIMAL HEALTH LTD/SCIENCE PHOTO LIBRARY

The male urethra – the tube through which urine exits the body – is home to an array of bacteria, some of which are probably picked up during vaginal sex.
Evelyn Toh at the Indiana University School of Medicine and her colleagues swabbed the urethras of 110 men who had no sexually transmitted infections or urethra-related issues. The men, average age 28, came from a range of ethnic and racial backgrounds. Transgender people weren’t included in the study.
Of these men, 92 provided swabs with sufficient levels of bacterial DNA for further analysis.
The detected bacteria could be separated into two groups – those that can live in the presence of oxygen and therefore probably dwell near the tip of the penis, and those that cannot live when oxygen is present and therefore probably dwell higher up in the urethra.
The former group was found in most of the men’s swabs and are probably native to the penile urethra, according to the researchers.
The latter group, however, was dominated by bacteria that are often disrupted in the condition bacterial vaginosis (BV), a common cause of unusual vaginal discharge that is thought to come about when the vagina’s microbiome gets out of sync.

Pulse Oximeters Confirmed to Be Biased for Black Kids

These patients are prone to get false negatives in hypoxemia

Tested against a gold standard, the widely accessible pulse oximetry technique turned out to overestimate arterial oxygen saturation in Black kids, researchers reported.
Among children with true hypoxemia according to directly measured arterial blood oxygen saturation (SaO₂<88%), a discordant finding of normoxemia by peripheral oxygen saturation levels on pulse oximetry (SpO₂≥92%), or a false negative, reached 12% of Black versus 4% of white patients, Halley Ruppel, PhD, RN, of the University of Pennsylvania in Philadelphia, and colleagues reported in JAMA Pediatricsopens in a new tab or window.
Conversely, among patients with normal SpO₂readings, 5% of Black children and 1% of white children turned out to have hypoxemia by SaO₂, Ruppel and colleagues added.
The unadjusted bias, or difference in values between SpO₂and SaO₂, was 2.58 (95% CI 2.15-3.00) for Black patients compared with 0.89 (95% CI 0.64-1.15) for white patients (P<0.001).

The A&P Professor Science & Education Updates

Discussion about this post