Friday, August 19, 2016

Did They Think the State was Kidding?

In July of 2015 the California legislature passed a law that requires all children to be vaccinated before they can attend school (see this blog, July 8, 2015). Unlike the previous law, the new law does not permit exceptions for either personal or religious beliefs. The new law will be phased in over seven years; this year and each subsequent year, all students entering kindergarten and the seventh grade will have to be vaccinated. (Current tenth- through twelfth-graders are exempt from the new law, as they'll all be out of school in three years anyway.)

The Sacramento Bee reports that in the Fulsom Unified School District, 145 kindergartners and seventh-graders were sent home on Tuesday last week (the first day of school) for failure to have the required vaccination documentation. By Friday, 98 of those students still had not returned to school. Do parents who oppose childhood vaccinations think the state is kidding? If they stick to their convictions they'll have to home-school their children.

I'm with the state and the school district on this one. It's time to hold the line against the anti-vaccine movement.

Tuesday, August 16, 2016

I'm Confused: Which Foods are Best/Worst for My Health?

Will eating more blueberries or broccoli help prevent cancer? Does oatmeal really reduce the risk of heart disease? How can we separate truth from fiction when it comes to the constant barrage of claims about certain foods?

The short answer is that it's difficult. That's because there's no easy way to prove that a certain food has a certain specific effect, given that so many other variables are in play at the same time. Most studies of specific foods and health rely on self-reported food consumption data, which is notoriously unreliable since people have a tendency to report what they think is the "right" answer. And such studies can't co ntrol for all the other variables in a person's life. So we're left, usually, with just a report of an "association" between a certain food and a certain medical effect. And as you know, an association (or correlation) doesn't prove cause and effect.

Want further evidence of the difficulty in evaluating the health effects of specific foods? Researchers from Harvard and Stanford Universities examined the recipes of a published cookbook and came up with a list of 50 common food ingredients. Then they surveyed the scientific literature to find out what had been published about that ingredient and the risk of cancer. Astonishingly, they found that 72% of the ingredients had been associated with either an increase or a decrease in cancer risk; some of the ingredients were reported to either increase or decrease risk in different studies.

I've stopped listening to the hype about any one food. I just try to eat a variety of foods, while keeping an eye on my weight. I'd like to report that I eat plenty of fresh fruits and vegetables and that I restrict my saturated fat intake, but that would be stretching it. You can do what you like; just don't believe that eating a lot of just one food is going to keep you from getting cancer, or prevent any other health problem for that matter.

Thursday, August 11, 2016

The U.S. Death Rate Increased in 2015

The death rate per 100,000 people in the U.S., also called the mortality rate, increased in 2015 for the first time in years, even when adjusted for age. The increase was slight but unusual; in a healthy society, death rates generally decline as a result of better nutrition and health care. So what happened in 2015?

For years, there has been a slow upward trend in the death rate among middle-aged whites, due to increases in drug- and alcohol-related deaths (see this blog, Dec. 13, 2015). Suicides have also been on the rise. In the past, these increases in deaths were more than offset by declines in deaths from specific diseases, such as heart disease and some cancers. But in 2015 the death rate from heart disease stopped declining. As a result, for the first time in a long time the overall death rate in the U.S. increased in 2015.

It would be unusual if this were the start of a new long-term trend in the U.S., for most developed and developing nations are still reporting annual declines in mortality. A long-term trend toward increases in mortality in the U.S. would be a worrying sign of a decline in overall societal health. Perhaps it will focus our attention on the rising death rate due drugs, alcohol, and suicides. Might many of these deaths be preventable?

Tuesday, August 9, 2016

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.

Wednesday, August 3, 2016

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.

Tuesday, July 26, 2016

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.

Thursday, July 21, 2016

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.