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IMAGE CREDIT: 
Sérgio Valle Duarte
, Wikimedia Commons // CC BY 3.0
IMAGE CREDIT: Sérgio Valle Duarte , Wikimedia Commons // CC BY 3.0

Scientists Say American Sperm Counts Are on the Decline

IMAGE CREDIT: 
Sérgio Valle Duarte
, Wikimedia Commons // CC BY 3.0
IMAGE CREDIT: Sérgio Valle Duarte , Wikimedia Commons // CC BY 3.0

Concerned scientists say the sperm count of men in Western nations has dropped significantly since the 1970s, a change that may signify underlying public health issues. They described their findings in the journal Human Reproductive Update.

The international team of researchers analyzed data from 185 studies of semen samples collected from 1973 to 2011. The 42,935 donors hailed from 50 countries, which the scientists divided into two groups: "Western," including North America, Europe, Australia, and New Zealand; and "Other," including South America, Asia, and Africa.

At first glance, the results are both concerning and surprising. The last 40 years seem to have seen a slow but significant sperm slump among American and other Western men. The studies recorded an average annual decrease of 1.6 percent, yielding a total loss of 59.3 percent over the 38-year study period.

The same could not be said for men in the "Other" group, whose sperm count appeared to experience no significant change.

The authors of the current paper seem alarmed by their own findings.

"The fact that the decline is seen in Western countries strongly suggests that chemicals in commerce are playing a causal role in this trend," co-author Shanna Swan of the Icahn School of Medicine at Mount Sinai told New Scientist.

Swan and her colleagues did not look into any possible causes of the decrease but believe it could be a sign of overall declining health in the West.

"A decline in sperm count might be considered as a 'canary in the coal mine' for male health across the lifespan," they write. "Our report of a continuing and robust decline should, therefore, trigger research into its causes, aiming for prevention."

But before we all freak out, it's important to consider other elements that could be influencing these results. First, the sperm samples were not distributed evenly across all 50 nations. Only 16 percent of samples came from North America, and there were far fewer studies on the "Other" group overall; it's possible that sperm populations in South America, Asia, and Africa are experiencing the same slow decline.

Second, these studies measured sperm count—not sperm quality.

Third, and most importantly, even with the decrease, the global average sperm count remains within normal range. While a downturn means that more men's count may fall beneath ideal levels, we’re hardly facing a worldwide sperm shortage. Let's take this situation one drop at a time.

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Medicine
New Cancer-Fighting Nanobots Can Track Down Tumors and Cut Off Their Blood Supply
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Scientists have developed a new way to cut off the blood flow to cancerous tumors, causing them to eventually shrivel up and die. As Business Insider reports, the new treatment uses a design inspired by origami to infiltrate crucial blood vessels while leaving the rest of the body unharmed.

A team of molecular chemists from Arizona State University and the Chinese Academy of Sciences describe their method in the journal Nature Biotechnology. First, they constructed robots that are 1000 times smaller than a human hair from strands of DNA. These tiny devices contain enzymes called thrombin that encourage blood clotting, and they're rolled up tightly enough to keep the substance contained.

Next, researchers injected the robots into the bloodstreams of mice and small pigs sick with different types of cancer. The DNA sought the tumor in the body while leaving healthy cells alone. The robot knew when it reached the tumor and responded by unfurling and releasing the thrombin into the blood vessel that fed it. A clot started to form, eventually blocking off the tumor's blood supply and causing the cancerous tissues to die.

The treatment has been tested on dozen of animals with breast, lung, skin, and ovarian cancers. In mice, the average life expectancy doubled, and in three of the skin cancer cases tumors regressed completely.

Researchers are optimistic about the therapy's effectiveness on cancers throughout the body. There's not much variation between the blood vessels that supply tumors, whether they're in an ovary in or a prostate. So if triggering a blood clot causes one type of tumor to waste away, the same method holds promise for other cancers.

But before the scientists think too far ahead, they'll need to test the treatments on human patients. Nanobots have been an appealing cancer-fighting option to researchers for years. If effective, the machines can target cancer at the microscopic level without causing harm to healthy cells. But if something goes wrong, the bots could end up attacking the wrong tissue and leave the patient worse off. Study co-author Hao Yan believes this latest method may be the one that gets it right. He said in a statement, "I think we are much closer to real, practical medical applications of the technology."

[h/t Business Insider]

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Medicine
New Peanut Allergy Patch Could Be Coming to Pharmacies This Year
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About 6 million people in the U.S. and Europe have severe peanut allergies, including more than 2 million children. Now, French biotechnology company DBV Technologies SA has secured an FDA review for its peanut allergy patch, Bloomberg reports.

If approved, the company aims to start selling the Viaskin patch to children afflicted with peanut allergies in the second half of 2018. The FDA's decision comes in spite of the patch's disappointing study results last year, which found the product to be less effective than DBV hoped (though it did receive high marks for safety). The FDA has also granted Viaskin breakthrough-therapy and fast-track designations, which means a faster review process.

DBV's potentially life-saving product is a small disc that is placed on the arm or between the shoulder blades. It works like a vaccine, exposing the wearer's immune system to micro-doses of peanut protein to increase tolerance. It's intended to reduce the chances of having a severe allergic reaction to accidental exposure.

The patch might have competition: Aimmune Therapeutics Inc., which specializes in food allergy treatments, and the drug company Regeneron Pharmaceuticals Inc. are working together to develop a cure for peanut allergies.

[h/t Bloomberg]

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