The Myopia Pandemic

August 28, 2015 by

Aug. 28, 2015

By Medical Discovery News

The Myopia Pandemic

You’ve probably heard of pandemics – the plague, influenza, HIV – but you might not have seen coverage of the growing myopia pandemic. Before you consider bathing in sanitizer, you should know that myopia isn’t contagious. Another word for it is nearsightedness.

Myopia is a condition in which close objects are seen clearly but distant objects are blurred due to the elongation of the eye or too much curvature of the cornea. This causes light entering the eye focusing in front of the retina rather than on it. Myopia is different than hyperopia, which is the kind of nearsightedness that comes from growing older. In fact, the myopia pandemic is primarily affecting young people.

It currently affects 90 percent of the young adults in China, although 60 years ago it was 10-20 percent. In the United States and Europe it affects about half of all young adults, double what it was 50 years ago. Seoul has the highest incidence: 96.5 percent of young people in South Korea’s capital have myopia. An estimated 2.5 billion people will experience myopia by 2020.

Vision issues can be corrected with glasses, contact lenses, or surgery, but none of those fix the underlying defect. Eye elongation can stretch and thin parts of the inner eye, which can increase the risk of retinal detachment, glaucoma, cataracts, and even blindness.

Genetic causes have been discounted, so this rapid change has to come from something in the environment. More than 400 years ago, Johannes Kepler, an astronomer and expert in optics, wrote that his intense studying led to nearsightedness. Today, students are not only studying a great deal but are also spending much of their time with cell phones, tablets, computers, and video games, primarily indoors.

Intense periods of reading and studying were disproved as a cause of myopia during a study in 2000. Seven years later, scientists from Ohio State University followed more than 500 eight- and nine-year-olds with healthy vision and tracked the time they spent outdoors. After five years, 20 percent had developed myopia, which correlated to the time they spent indoors. This was confirmed one year later, when scientists in Australia studied 4,000 students and also reported that the amount of time spent indoors was the important factor.

It’s probably because the retina of the eye produces and releases more dopamine, a neurotransmitter, during the day to signal the eye to switch from night to daytime vision. Indoor light disrupts this cycle, affecting eye development. Only 30 percent of Australian children who spent three or more hours outside each day had myopia. A systematic review paper aggregated previous studies and concluded that each hour of each week spent outside reduces a child’s chance of developing myopia by 2 percent.

Researchers are examining possible ways to control the development of myopia, such as altering the way contact lenses focus light, producing eye drops that block neurotransmitter release, and using artificial lights like those used to treat seasonal affective disorder, also known as winter depression. Of course, having children play or simply be outside seems the best option, and it has other health benefits too.

For a link to this story, click here.

Filed Under: Health Tagged With: , , , , , , , , , , , , , , , , , , , , , , ,

Zombies? Not Quite

December 1, 2012 by

By Medical Discovery News

Nov. 31, 2012

When a nude Miami man chewing on another man’s face made headlines and sparked fears of “zombie” attacks, the public became acutely aware of a designer drug with the street name “bath salts.” Authorities speculated the man was high on bath salts since similar bizarre events were reported in other cities. Toxicology reports have since shown the man only had marijuana in his system. Yet the case highlights the growth of designer drugs and the violent highs they create while skirting the law.

Bath salts’ innocuous name is meant to make them appear safe and legal. They resemble bath crystals but are synthetic drugs sold under innocent names such as “Ivory Wave,” “Purple Wave,” “Vanilla Sky,” and “Bliss,” and are widely available on the Internet, head shops and some convenience stores. To confuse the public even further, they’re also sold as glass cleaners or plant food, which again is an attempt at avoiding drug laws.

Sold in small packets, these stimulants can be smoked, swallowed, snorted, or put into a solution and injected. They’re far cheaper and easier to get than cocaine or ecstasy, yet like those, they act on the central nervous system with far less predictable effects. Since “street chemists” produce bath salts, no one knows exactly what’s in them.

The main compounds in bath salts are synthetic stimulants including MDPV, mephedrone, and methylone, but there are many others. These compounds are synthetic derivatives of cathinones, which are naturally found in the Catha edulis plant. The North African shrub known as khat is a hallucinogenic stimulant and illegal in the U.S. But the synthetic derivatives are far more concentrated and acutely toxic.

Bath salts affect behavior by altering levels of the neurotransmitters dopamine, norepinephrine, and serotonin. Dopamine controls movement, emotional responses, and the ability to experience pleasure and reward. Norepinephrine regulates heart rate, blood pressure, and sugar levels, and is part of the fight or flight response. Serotonin modulates mood, emotion, sleep, and appetite, and is implicated in the control of numerous behavioral and physiological functions.

Bath salts raise the concentration of these neurotransmitters in two ways. First, they block the reuptake of neurotransmitters, leaving extra dopamine, norepinephrine, and serotonin to react with other receptors instead of being stored safely inside neurons. Second, the drug stimulates the release of additional internal stores of neurotransmitters.

The results are increased heart rate and blood pressure, agitation, anxiety, hallucinations, extreme paranoia, and even full-blown psychosis. There also have been cases of suicide days after the more obvious effects of the drugs have worn off.

In October 2011, the US Drug Enforcement Agency banned three of the key ingredients used to make bath salts for at least a year, and 40 states have outlawed the drug. But producers can make small chemical adjustments in the molecules to stay ahead of the law, which challenges the legal system’s ability to crack down on drug use. The drug is mostly being made in China and imported through other countries, but that’s expected to change as dealers learn to manufacture it here in the United States.

For a link to this story, click here.

Filed Under: Health Tagged With: , , , , , , , , , , , , , , , , , ,

Micro(bes)

October 17, 2012 by

By Medical Discovery News

Oct. 13, 2012

Compression of the proteins of this bacterial virus can generate small amounts of an electric current

Increasingly, the mind-blowing technology portrayed in science fiction movies comes to life in labs around the world. As engineering interfaces with the physical sciences, remarkable new advances in biomedicine happen. Two recently published studies in particular have the feel of “Star Wars.”

One involves engineering viruses to generate electricity, with the hope they’ll one day power nano-size devices implanted in the human body. These viruses, called bacteriophage, attack bacteria. Bacteriophages are simple organisms with a small number of proteins and a genome consisting of DNA or RNA, both gene-encoding molecules. The proteins coat the genome, protecting it as it enters a bacterium’s cell. It’s the unique structure of these proteins that scientists are now exploiting.

In a bacteriophage called M13, the proteins have two distinct parts. One end is positively charged and the other end of the protein, facing out, is more negatively charged. This arrangement of opposing charges at opposite ends of the same molecule can be exploited in a piezo-electric effect.

Piezo-electric means when the shape of these molecules is compressed, they generate an electric current. A mechanical button on outdoor gas grills works the same way when pressed. Researchers used the same concept to build tiny generators made out of biomolecules that could be activated by a person’s movements, such as stair climbing.

These microgenerators could potentially power implanted devices that diagnose disease or monitor therapeutic treatments. In the future, such devices might sense and report the levels of medically important compounds like glucose or neurotransmitters. A step beyond that would use microgenerators as a power source for implanted devices, such as the cochlear implant or “bionic ear” for the hearing impaired, which currently uses an external battery.

Another technology with significant implications for human health is the biological ion transistor computer chip – the first ever produced. In these biological transistors, charged molecules called ions take the place of electrons found in a traditional transistor. In essence, this means a computer chip can now network with human cells.

In recent experiments in Sweden, researchers have been using a powerful neurotransmitter called acetylcholine as the charged molecule. Acetylcholine is a muscle activator that, when released by a neuron, initiates movement. This happens when a message from the brain travels along the nerves to a muscle, like the bicep. Then a neuron transmits acetylcholine ions to nearby muscle cells, triggering the arm to move. In theory, the ion transistor could be wired and integrated into the nervous system to accomplish the same job.

In the future, this could allow fine control of muscle movement or more importantly, restore movement in people with paralysis. The experiments in Sweden have only worked with acetylcholine, but researchers believe the same technology could be used with other charged molecules. A chip could be made to balance serotonin levels, thereby acting as an antidepressant. One could even be made to monitor and boost the immune response when an invading virus or bacteria is present.

For a link to this article, click here.

Filed Under: Health Tagged With: , , , , , , ,