Frequent Sighing Helps Keep You Alive

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iStock

Good news for hopeless romantics and the perpetually dismayed: All that sighing is good for you. In fact, you’d die without it. Scientists have now pinpointed the region in the brain that transforms normal breathing into a life-giving sigh. They published their findings this week in the journal Nature.

Let’s start with the mechanics. Physiologically speaking, sighing is a way of keeping your lungs inflated. “A sigh is a deep breath, but not a voluntary deep breath,” study co-author Jack Feldman said in a press release. “It starts out as a normal breath, but before you exhale, you take a second breath on top of it.” Whether you realize it or not, you do this about 12 times an hour, and even more than that when you’re stressed or anxious. And it’s a good thing you do. “If you don’t sigh every five minutes of so, the alveoli will slowly collapse, causing lung failure,” Feldman said. “That’s why patients in early iron lungs had such problems, because they never sighed.” The machines had not been programmed to give patients regular deep, lung-filling breaths.

One group of researchers sifted through nearly 19,000 gene expression patterns in the active brains of mice, looking for the root of the sigh reflex. It was much smaller than they expected: just one little bundle of 200 cells in the brain stem, releasing one of two molecules called peptides. They shared their data with Feldman’s lab, and together the team found another set of 200 cells on the peptide receiving end.

A mouse's sigh clusters. Image credit: Stanford/Krasnow Lab

When the scientists prevented one peptide from reaching its goal, the rate of the mice’s sighing was cut in half. Blocking both peptides caused the mice to stop sighing altogether. “Unlike a pacemaker that regulates only how fast we breathe, the brain’s breathing center also controls the type of breath we take,” co-author Mark Krasnow noted in the press release. “It’s made up of small numbers of different kinds of neurons. Each functions like a button that turns on a different type of breath. One button programs regular breaths, another sighs, and the others could be for yawns, sniffs, coughs, and maybe even laughs and cries.”

It’s highly unusual for such small clusters of neurons to have so much power, Feldman said. “Sighing appears to be regulated by the fewest number of neurons we have seen linked to a fundamental human behavior.” The team’s findings may someday lead to treatment for people with diseases that limit their breathing. “These molecular pathways are critical regulators of sighing, and define the core of a sigh-control circuit,” Krasnow said. “It may now be possible to find drugs that target these pathways to control sighing.”

A Simple Skin Swab Could Soon Identify People at Risk for Parkinson's

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iStock.com/stevanovicigor

More than 200 years have passed since physician James Parkinson first identified the degenerative neurological disorder that bears his name. Over five million people worldwide suffer from Parkinson’s disease, a neurological condition characterized by muscle tremors and other symptoms. Diagnosis is based on those symptoms rather than blood tests, brain imaging, or any other laboratory evidence.

Now, science may be close to a simple and non-invasive method for diagnosing the disease based on a waxy substance called sebum, which people secrete through their skin. And it’s thanks to a woman with the unique ability to sniff out differences in the sebum of those with Parkinson's—years before a diagnosis can be made.

The Guardian describes how researchers at the University of Manchester partnered with a nurse named Joy Milne, a "super smeller" who can detect a unique odor emanating from Parkinson's patients that is unnoticeable to most people. Working with Tilo Kunath, a neurobiologist at Edinburgh University, Milne and the researchers pinpointed the strongest odor coming from the patients' upper backs, where sebum-emitting pores are concentrated.

For a new study in the journal ACS Central Science, the researchers analyzed skin swabs from 64 Parkinson's and non-Parkinson's subjects and found that three substances—eicosane, hippuric acid, and octadecanal—were present in higher concentrations in the Parkinson’s patients. One substance, perillic aldehyde, was lower. Milne confirmed that these swabs bore the distinct, musky odor associated with Parkinson’s patients.

Researchers also found no difference between patients who took drugs to control symptoms and those who did not, meaning that drug metabolites had no influence on the odor or compounds.

The next step will be to swab a a much larger cohort of Parkinson’s patients and healthy volunteers to see if the results are consistent and reliable. If these compounds are able to accurately identify Parkinson’s, researchers are optimistic that it could lead to earlier diagnosis and more effective interventions.

[h/t The Guardian]

World’s Oldest Stored Sperm Has Produced Some Healthy Baby Sheep

A stock photo of a lamb
A stock photo of a lamb
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It’s not every day that you stumble across a 50-year-old batch of frozen sheep sperm. So when Australian researchers rediscovered a wriggly little time capsule that had been left behind by an earlier researcher, they did the obvious: they tried to create some lambs. As Smithsonian reports, they pulled it off, too.

The semen, which came from several prize rams, had been frozen in 1968 by Dr. Steve Salamon, a sheep researcher from the University of Sydney. After bringing the sample out of storage, researchers thawed it out and conducted a few lab tests. They determined that its viability and DNA integrity were still intact, so they decided to put it to the ultimate test: Would it get a sheep pregnant? The sperm was artificially inseminated into 56 Merino ewes, and lo and behold, 34 of them became pregnant and gave birth to healthy lambs.

Of course, this experiment wasn’t just for fun. They wanted to test whether decades-old sperm—frozen in liquid nitrogen at -320°F—would still be viable for breeding purposes. Remarkably, the older sperm had a slightly higher pregnancy rate (61 percent) than sheep sperm that had been frozen for 12 months and used to impregnate ewes in a different experiment (in that case, the success rate was 59 percent).

“We believe this is the oldest viable stored semen of any species in the world and definitely the oldest sperm used to produce offspring,” researcher Dr. Jessica Rickard said in a statement.

Researchers say this experiment also lets them assess the genetic progress of selective breeding over the last five decades. “In that time, we’ve been trying to make better, more productive sheep [for the wool industry],” associate professor Simon de Graaf said. “This gives us a resource to benchmark and compare.”

[h/t Smithsonian]

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