Turning Sutures Into Sensors

A number of wearable and implantable sensors are now used to collect medical information from patients. It's possible, for example to wear devices that monitor body temperature, heart rate, steps taken, etc. A limitation of most wearable sensors is that they must lie relatively flat against the body. More importantly, none are very effective at monitoring the complex chemical changes that can take place within the body.

A breakthrough technology of the future may be to create "smart thread" - specialized types of sutures that could be used as sensors. Sutures are flexible, cheap, and easily implanted into the skin or even into organs. Researchers at Tufts University are studying how to coat sutures with conductive materials so that they might be used to monitor mechanical activity or chemical activity. Coating stretchable suture material with nanotubes and silicone causes the thread's resistance to change when they are stretched, so that by passing a small amount of current through the thread, sutures could be used to measure physical strain. By taking advantage of the wicking properties of some fibers (most notably cotton), sutures could be used to monitor the complex biochemistry of interstitial fluid in real time. Such sutures might be particularly useful in monitoring the progress of wound healing, where local conditions (pH, electrolytes, and glucose, for example) might be quite different from conditions elsewhere in the body.

So far, most of these ideas are just that: ideas. But the Tufts researchers are laying the groundwork with experiments in rats and in animal tissues such as chicken skin. Don't be surprised if someday your physician suggests using a smart suture to monitor some aspect of your health.

Hybrids and the Environmental Protection Act

In the 43 years since it was written, the Endangered Species Act (ESA) has played a key role in the recoveries from near-extinction of several species, including the bald eagle, the humpback whale, and the gray wolf. However, the ESA doesn't address hybrids - organisms produced when individuals of two different species mate and produce viable offspring. The problem of what to do about endangered hybrids has now come to the forefront, thanks (or no thanks) to a powerful new tool in biology, DNA sequencing.

The classic definition of a species is "a group of organisms that under natural conditions tend to breed within that group." Most species can't breed with other species and produce viable offspring. But there are exceptions; wolves, for example, can (and occasionally do) interbreed with dogs or coyotes. And that brings us to the problem of which wolves, if any, should be protected by the ESA.

The ESA currently recognizes (and protects) two species of wolves. Gray wolves are found primarily in the western U.S.; their population is recovering, thanks to protection under the ESA. Red wolves were once found in the southeast U.S. but now exist only in captivity; they, too, are protected. In addition, scientists have recently suggested that wolves in the eastern U.S. should also be listed as a separate protected species, to be called the Eastern wolf.

But now new research, using DNA sequencing, has revealed that the Eastern wolf and the red wolf are actually hybrids, produced by interspecies mating between gray wolves and coyotes. That creates a problem for the ESA. If Eastern and red wolves are just hybrids of two true species, should we attempt to save them? And if there is just one species of wolf, does its total population still warrant protection under the ESA?

The Environmental Protection Act is showing its age. It needs to be able to take into account new findings derived from DNA sequencing. And it needs to address what to do (if anything) about hybrids.

A New Map of the Cerebral Cortex

The map used in most textbooks to describe the functional regions of the cerebral cortex is admittedly rather old. Fortunately, it has just been updated. Using data collected as part of the Human Connectome Project, researchers examined over 1,200 brain scans looking at not one, but four features; architecture, function, connectivity and topography. They identified nearly 180 distinct areas of the cerebral cortex - more than double the number described in the past. The researchers also created a computer program that can recognize each area in an individual brain being studied.

What makes each region different and how they communicate with each other will likely be areas of active research for years to come. Of specific interest will be how the areas are involved in specific neurologic disorders. Dreaming big, we might imagine a future in which doctors could diagnose specific brain disorders from an MRI (magnetic resonance image), just by looking at changes in specific brain areas.

We're Just One Step Away From a Superbug

The possibility that a strain of bacteria might develop total resistance to all known antibiotics (i.e., a superbug) continues to haunt us. Slowly but surely, more and more bacteria are increasing their resistance to antibiotics faster than we can create new antibiotics. No bacterium is completely resistant to all antibiotics yet, but a recent discovery suggests that we are just one step away from that point.

Right now, one of the most antibiotic-resistant of all bacteria is carbapenum-resistant Enterobacteriaceae (CRE for short). CRE has developed resistance to all antibiotics except an old antibiotic developed 50 years ago, called colistin. But now researchers have discovered a strain of E. coli bacteria that is resistant to colistin. If this strain of E. coli ever transfers its genetic material to CRE (the equivalent of bacterial mating), then we are in for real trouble.

Will it ever happen? No one knows. But bacteria have proven themselves to be highly adaptable. The era when antibiotics were the answer to bacterial infections may be coming to an end. We may have to find new ways to combat the bacteria of the future.

Sexual Transmission of the Zika Virus

In healthy adults, the Zika virus causes only mild flu-like symptoms.  80% of infected adults never even know they are infected. However it's a dangerous virus nonetheless, because women who are infected during their pregnancies can give birth to infants with a birth defect called microcephaly.

When Zika first appeared in South America, it was believed that the virus was transmitted exclusively by mosquitoes that thrive in South American countries with warm, humid climates. However we now know that the Zika virus can be sexually transmitted. Until yesterday, all 14 documented cases of sexually transmitted infections in the U.S. had been caused by Zika-infected men (who infected their partners, either male or female). But now the CDC has reported the first documented case of transmission from an infected woman to her male partner in the U.S. The significance of sexual transmission is that it raises the possibility of an outbreak of Zika virtually anywhere in the world, not just in areas in which the Zika-transmitting mosquito is found.

Scientists are working feverishly on a vaccine to prevent Zika infections. It will take some time before one is available. In the meantime, pregnant women (and their male partners) should be aware of the dangers of traveling to countries where the Zika-transmitting mosquito is common.

Nobel Laureates Support Genetically Modified Organisms (GMOs)

In an open letter published online, more than 100 Nobel Laureates are urging the environmental organization Greenpeace to stop their crusade against GMOs. Over 90% of the letter's signatories earned their Nobel prizes in the fields of physics, chemistry, or medicine. According to the letter's signatories, GMOs have been proven to be safe and have the potential to improve nutrition and feed a hungry world in the future. The letter suggests that opposition to GMOs is based on emotion and dogma, rather than facts. It concludes, "How many more poor people in the world must die before we consider this a 'crime against humanity'"?

The issue of the safety of GMOs is one of those areas in which the views of the public and of scientists are still far apart. A Pew Research Center study revealed last year that while 88% of scientists affiliated with the American Association for the Advancement of Science say that GMOs are generally safe, only 37% of the public thinks so.

In other related news, this month Vermont became the first state to require that food product labels indicate whether or not the product contains GMO ingredients. Other states are likely to follow suit. Clearly, the fight over GMOs is not over yet.

Prescription Contraceptives Via App or Website

It is now possible to obtain prescription contraceptives without ever having to schedule a visit to a doctor's office. A growing number of websites and apps allow you to fill out your personal and health information online or on an app and then have a videoconference or phone conversation with a licensed doctor; after approval of your prescription, your contraceptives (pills, patches, and in some cases even the morning-after pill) can be shipped directly to you.

Contraceptives are currently available only by prescription. Health professionals believe that contraceptives are so safe that they could be made available over-the-counter. However, over-the-counter availability would require approval from the FDA, an expensive and time-consuming effort most drug companies wish to avoid. In addition, the widespread availability of contraceptives without any medical approval at all would likely meet with opposition from conservative groups.

A few states allow pharmacists to write contraceptive prescriptions, but most do not. Web-and app- based services that connect patients to a doctor without a visit to a doctor' office are yet another way to make contraceptives more readily available. Health professionals hope that by making it easier for women to obtain contraceptives, these web-and app-based services will lead to a further reduction in the rate of unintended pregnancies.

For a description of some of the current websites and apps, see this article in the New York Times.