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Brain Scans Show 4 Different Types of Depression

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Scientists say they’ve found neurological evidence of four different subtypes of depression—a discovery that may someday help doctors select the best treatment for their depressed patients. The research was published in the journal Nature Medicine.

Depression is an exceptionally slippery beast. Unlike ailments located elsewhere in the body, mental illnesses are classified and diagnosed not by concrete physical signs, or biomarkers, but by patients’ behavior. There are a lot of problems with this approach, including the fact that a lot of different illnesses can cause the same symptoms—and that the same illness can cause different symptoms in different people.

What we call “depression” is an experience that likely has many different causes, co-author Conor Liston of Weill Cornell Medical College told Scientific American. “The fact that we lump people together like this has been a big obstacle in understanding the neurobiology of depression.”

Liston and his colleagues analyzed functional magnetic resonance imaging (fMRI) scans from 17 different research sites around the world. They took in scans from 1188 people, about 40 percent of whom had depression, and were able to look closely at an astounding 258 brain regions in each person.

The team had expected to find some differences between the brains of people with depression and without. They found those, but they also found differences within the group of depressed people. Differences in brain activity and connectivity revealed four distinct subtypes among people with depression.

Most excitingly, these brain-activity subtypes matched up with different medical profiles. Patients in subtypes 1 and 2 described feeling more fatigue, while people in subtypes 3 and 4 had trouble feeling pleasure.

The subtypes also responded differently to treatment techniques. People in subtype 1, for example, were more likely to experience relief with transcranial magnetic stimulation (TMS), a non-pharmaceutical method that uses electromagnetic impulses to stimulate a sluggish brain.

More research is needed, but these findings are both heartening and promising, Liston says. Depression “is not just one biological thing.”

[h/t Scientific American]

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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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