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Two Common Antibiotics Don’t Work the Way We Thought

The secret lives of antibiotics are more interesting than we ever knew. Researchers analyzing two commonly prescribed drugs say these medications attack bacteria using never-before-seen techniques—a discovery that could help us develop better drugs in the future. The team published its findings in the Proceedings of the National Academy of Sciences.

Chloramphenicol (CHL) is an aggressive broad-spectrum antibiotic that’s been around since the 1940s. It’s injected intravenously to treat serious infections like meningitis, cholera, plague, and anthrax, but the risks of use are so extreme that it’s typically only used as a drug of last resort.

Linezolid (LZD) is both newer and gentler. It’s prescribed for common illnesses like pneumonia and strep, but has also proven itself against drug-resistant bacteria like the one that causes the staph infection MRSA.

Despite differences in their structure, the two drugs fight disease the same way many other antibiotics do: by sticking to the catalytic center of a bacterial cell and blocking its ability to synthesize proteins. Because other drugs are universal inhibitors—that is, they prevent any and all synthesis—scientists assumed CHL and LZD would be, too.

Researchers at the University of Illinois, Chicago were not content to assume. They wanted to know for sure what the two antibiotics were up to. They cultured colonies of E. coli bacteria, exposed them to strong doses of CHL and LZD, then sequenced the beleaguered bacteria’s genes to see what was going on inside.

As expected, CHL and LZD were all up on the bacteria’s ribosomes, frustrating its attempts to put proteins together. But the drugs weren’t as totalitarian as scientists had believed. Instead, their approach seemed both specific and context-dependent, switching targets based on which amino acids were present.

"These findings indicate that the nascent protein modulates the properties of the ribosomal catalytic center and affects binding of its ligands, including antibiotics," co-author Nora Vazquez-Laslop said in a statement. In other words: It seems amino acids have a lot more influence than we realized.

As so often happens in science, finding these answers also raised a lot of questions (like "How many other antibiotics have we mischaracterized?"), but it also opens a door for medical science, said co-author Alexander Mankin.

"If you know how these inhibitors work, you can make better drugs and make them better tools for research. You can also use them more efficiently to treat human and animal diseases."

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Feeling Anxious? Just a Few Minutes of Meditation Might Help
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Some say mindfulness meditation can cure anything. It might make you more compassionate. It can fix your procrastination habit. It could ward off germs and improve health. And it may boost your mental health and reduce stress, anxiety, depression, and pain.

New research suggests that for people with anxiety, mindfulness meditation programs could be beneficial after just one session. According to Michigan Technological University physiologist John Durocher, who presented his work during the annual Experimental Biology meeting in San Diego, California on April 23, meditation may be able to reduce the toll anxiety takes on the heart in just one session.

As part of the study, Durocher and his colleagues asked 14 adults with mild to moderate anxiety to participate in an hour-long guided meditation session that encouraged them to focus on their breathing and awareness of their thoughts.

The week before the meditation session, the researchers had measured the participants' cardiovascular health (through data like heart rate and the blood pressure in the aorta). They evaluated those same markers immediately after the session ended, and again an hour later. They also asked the participants how anxious they felt afterward.

Other studies have looked at the benefits of mindfulness after extended periods, but this one suggests that the effects are immediate. The participants showed significant reduction in anxiety after the single session, an effect that lasted up to a week afterward. The session also reduced stress on their arteries. Mindfulness meditation "could help to reduce stress on organs like the brain and kidneys and help prevent conditions such as high blood pressure," Durocher said in a press statement, helping protect the heart against the negative effects of chronic anxiety.

But other researchers have had a more cautious outlook on mindfulness research in general, and especially on studies as small as this one. In a 2017 article in the journal Perspectives on Psychological Science, a group of 15 different experts warned that mindfulness studies aren't always trustworthy. "Misinformation and poor methodology associated with past studies of mindfulness may lead public consumers to be harmed, misled, and disappointed," they wrote.

But one of the reasons that mindfulness can be so easy to hype is that it is such a low-investment, low-risk treatment. Much like dentists still recommend flossing even though there are few studies demonstrating its effectiveness against gum disease, it’s easy to tell people to meditate. It might work, but if it doesn't, it probably won't hurt you. (It should be said that in rare cases, some people do report having very negative experiences with meditation.) Even if studies have yet to show that it can definitively cure whatever ails you, sitting down and clearing your head for a few minutes probably won't hurt.

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Women Suffer Worse Migraines Than Men. Now Scientists Think They Know Why
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Migraines are one of medicine's most frustrating mysteries, both causes and treatments. Now researchers believe they've solved one part of the puzzle: a protein affected by fluctuating estrogen levels may explain why more women suffer from migraines than men.

Migraines are the third most common illness in the world, affecting more than 1 in 10 people. Some 75 percent of sufferers are women, who also experience them more frequently and more intensely, and don't respond as well to drug treatments as men do.

At this year's Experimental Biology meeting in San Diego, researcher Emily Galloway presented new findings on the connection between the protein NHE1 and the development of migraine headaches. NHE1 regulates the transfer of protons and sodium ions across cell membranes, including the membranes that separate incoming blood flow from the brain.

When NHE1 levels are low or the molecule isn't working as it's supposed to, migraine-level head pain can ensue. And because irregular NHE1 disrupts the flow of protons and sodium ions to the brain, medications like pain killers have trouble crossing the blood-brain barrier as well. This may explain why the condition is so hard to treat.

When the researchers analyzed NHE1 levels in the brains of male and female lab rats, the researchers found them to be four times higher in the males than in the females. Additionally, when estrogen levels were highest in the female specimens, NHE1 levels in the blood vessels of their brains were at their lowest.

Previous research had implicated fluctuating estrogen levels in migraines, but the mechanism behind it has remained elusive. The new finding could change the way migraines are studied and treated in the future, which is especially important considering that most migraine studies have focused on male animal subjects.

"Conducting research on the molecular mechanisms behind migraine is the first step in creating more targeted drugs to treat this condition, for men and women," Galloway said in a press statement. "Knowledge gained from this work could lead to relief for millions of those who suffer from migraines and identify individuals who may have better responses to specific therapies."

The new research is part of a broader effort to build a molecular map of the relationship between sex hormones and NHE1 expression. The next step is testing drugs that regulate these hormones to see how they affect NHE1 levels in the brain.

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