The Myopia Pandemic

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.

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Zombies? Not Quite

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.

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Study Buddies

By Medical Discovery News

Sept. 29, 2012

Study Buddies

The go-to stimulant to fuel all night study sessions or write a big paper was always caffeine. But now students are tempted by a prescription drug said to be so effective at enhancing mental performance it’s called a cognitive steroid. A recent study revealed 20 percent of college students report having taken Adderall to improve studying and test-taking skills. Some students smoke, snort, or inject the drug for instantaneous focus. But like most easy fixes, it comes with a price: addiction.

Adderall is a combination of dextroamphetamine and amphetamine routinely prescribed to control the symptoms of attention deficit hyperactivity disorder (ADHD) and narcolepsy. There are two forms of Adderall: a rapid release pill that lasts four to six hours and the slow release pill that extends the effects for up to 12 hours. It works, in part, by elevating the amount of dopamine in the brain. For those with ADHD, this neurotransmitter is deficient in the frontal cortex where executive functions such as reasoning, planning, focusing, and problem solving take place. Users report first feeling a mild euphoria, which then gives way to a calming sensation and eventually grogginess as it wears off.

In people without ADHD, drugs like Adderall and a similar drug, Ritalin, are appealing because they can enhance mental performance and lower fatigue. Adderall may also increase alertness, concentration, and mental processing speed. When sitting down to a task like writing, users find they are intensely focused and work for long hours, although some say at the cost of creativity. Hence it has become the drug of choice for overachievers. Despite what some believe, these neuroenhancers are not benign.

Many side effects of Adderall aren’t serious, but more severe side effects include aggression, depression, suicidal thoughts, hallucinations, fainting, and seizures. Someone who stops taking the drug after using it regularly for more than a few weeks or in high doses will suffer withdrawal symptoms like anxiety, depression, fatigue, hypersomnia, insomnia, paranoia, hyperactivity, irritability, or personality changes. Severe cases of withdrawal can cause psychosis long after Adderall is stopped. Surveys show most college students who abuse Adderall also abuse alcohol and are three times more likely to use marijuana, five times more likely to abuse pain relievers, and eight times more likely to use cocaine or abuse tranquilizers.

Many people may be shocked to learn Adderall is a controlled substance grouped with other highly addictive drugs like cocaine. Addiction treatment centers across the country have programs for Adderall abuse. Possessing it without a prescription is illegal and prosecuted as a felony charge in many states.

Despite the downsides of neuroenhancers, they may have a place in improving human health. As the population ages, cognitive enhancers can improve quality of life and compensate for mental decline. But the long-term effects of these drugs are still unknown and need to be studied so that individuals can make responsible decisions about their use.

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A Vaccine for Cocaine

By Medical Discovery News

Feb. 4, 2012

A Vaccine for Cocaine

In the city that never sleeps, 274 people died due to cocaine abuse last year, according to the New York Post. While that figure has decreased by almost half in the past four years in New York City alone, scientists are attempting to create vaccines to end the addiction for millions of people around the world.

Despite the general belief that drug addiction is a moral failure rather than a physical disease, developing and producing inexpensive vaccines for addicts can reduce the hundreds of millions of dollars spent on their medical care and incarceration. Plus, it can help turn their lives around.

After 20 years of work by a number of different scientists, a cocaine vaccine is showing promising results. A trial study by an arm of the National Institutes of Health showed the vaccine reduced cocaine use in 38 percent of vaccinated patients. It works by stimulating the immune system to produce anti-cocaine antibodies that attack cocaine molecules in the blood, preventing them from traveling to organs such as the brain. If it’s not allowed in the brain, cocaine can’t induce a high. Therefore, over time, the patient may have a better chance at kicking the addiction.

Cocaine works by binding to receptors that normally would receive dopamine from another neuron. That leaves excess dopamine stuck between neurons, stimulating these neurons to fire repeatedly, creating the euphoria users feel. Some scientists believe this high makes cocaine the most addictive of drugs and is the reason why behavior therapy has not been effective in helping addicts stay off the drug.

A complication in developing the vaccine was the small size of the cocaine molecule, which does not generate a good immune response and high levels of antibodies. So, the idea was to link it to a large protein molecule. Researchers focused on an unlikely partner molecule – the cholera toxin B, a portion of cholera toxin that does not cause disease, but will stimulate the immune system to respond.

Researchers then attached this portion of the toxin to the cocaine molecule. Once the vaccine is injected, it induces production of antibodies that then circulate in the blood. When an addict uses cocaine, the antibodies bind to the molecule and prevent it from entering the brain.

The vaccine is a strict regimen of five shots over 12 weeks, a schedule that was challenging for many addicts to meet. In those that did, a third saw positive results. After two months, they needed a booster vaccine to maintain the proper level of cocaine antibodies. Researchers say the next step is to make the vaccine effective for a larger proportion of the people taking it, and to maintain the antibody level for longer than two months. It’s also clear that counseling and behavior therapy is necessary to control urges since the vaccine does not affect this physical component of the addiction.

Making a cocaine vaccine available to a wide range of people in both developed and developing countries would curb the damaging toll of this drug.

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