Sunday, March 14, 2010

“Psychopaths wired to seek reward at any cost: study (AFP via Yahoo! News)” plus 2 more

“Psychopaths wired to seek reward at any cost: study (AFP via Yahoo! News)” plus 2 more

Psychopaths wired to seek reward at any cost: study (AFP via Yahoo! News)

Posted: 14 Mar 2010 04:26 PM PDT

PARIS (AFP) – The brains of psychopaths could be hardwired to seek reward even when the consequences are life-threatening to others or themselves, according to a study released Sunday.

A naturally-occurring chemical, dopamine, plays a key role in some forms of pathologically violent behaviour and drug addiction, the study found.

Previous research has focused on what psychopaths tend to lack -- fear, empathy and the ability to maintain normal relationships.

But a team led by Joshua Buckholtz of Vanderbilt University in Nashville, Tennessee examined what there is too much of, namely impulsiveness and an extreme attraction to risk-taking and rewards.

"Lack of sensitivity to punishment and a lack of fear are not particularly good predictors of violence or criminal behavior," said colleague and co-author David Zald.

The new data, published in Nature Neuroscience, suggests that psychopaths "have such a strong draw to reward -- to the carrot -- that it overwhelms the sense of risk or concern about the stick," he said.

The key may be dopamine, a neurotransmitter known to affect cognition and behaviour, especially related to motivation, punishment and gratification.

Cocaine, alcohol and nicotine all stimulate the brain's dopamine circuits.

Other pathological states linked to dopamine dysfunction include autism, schizophrenia, and attention deficit hyperactivity disorder (ADHD).

"Psychopaths are often thought of as cold-blooded criminals who take what they want without thinking about consequences," Buckholtz said.

"We found that a hyper-reactive dopamine reward system may be the foundation for some of the most problematic behaviors associated with psychopathy, such as violent crime, recidivism and substance abuse."

The evidence came from brain scans of volunteers ranked according to their psychopathic traits through psychological testing.

Violent criminals were at the far end of the spectrum, followed by normally functioning persons who were nonetheless manipulative, aggressive and risk-takers.

In the first experiment, positron emission tomography, or PET, imaging was used to measure dopamine release in the brain after the participants had been given a dose of amphetamine, more commonly known as "speed".

"Our hypothesis was the psychopathic traits are also linked to dysfunction in dopamine reward circuitry," Buckholtz said.

As predicted, the drug triggered the release of nearly four times as much dopamine in people at the high end of the psychopathy scale.

In the second test, volunteers were told they would receive money for completing a simple task. Their brains were scanned via functional magnetic imaging, or fMRI, as they did so.

Once again, in those individuals scoring high on the ranking, the dopamine-related reward centre in the brain was far more active than in the other participants.

"It may be that because of these exaggerated dopamine responses, once they focus on the chance to get a reward, psychopaths are unable to alter their attention until they get what they're after," Buckholtz said.

"With these two very different techniques, we saw a very similar pattern -- both were heightened in individuals with psychopathic traits," he added.

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'Tommy John' elbow reconstruction 95 percent successful with grown teen pitchers, study says (Science Daily)

Posted: 14 Mar 2010 01:10 PM PDT

ScienceDaily (Mar. 13, 2010) — A new study presented March 13 at the American Orthopaedic Society for Sports Medicine's (AOSSM) Specialty Day in New Orleans found that 95 percent of skeletally mature high school pitchers were satisfied with their "Tommy John" elbow reconstruction surgery. Almost as many (94.7 percent) returned to competitive baseball.

"Tommy John" surgery is a procedure where a damaged elbow ligament (ulnar collateral ligament or UCL) is replaced with a tendon from elsewhere in the body. The surgery is named for Hall of Fame pitcher Tommy John, who was the first person to have the surgery in 1974. John returned to the major leagues and went on to win 164 games after the surgery. Prior to this historic surgery, a UCL injury was a career-ending injury.

"High school kids have been a grey zone for this surgery," said Michael J. Angel, MD, of Premier Orthopaedics of Westchester and Rockland. "Obviously, surgeons would avoid surgery on young patients whose growth plates had not closed. But this study can give surgeons the confidence to recommend this surgery to teenage skeletally mature athletes. It also gives the teen and their parents assurance that the surgery should go well."

In the study, 20 high school baseball pitchers between 16 -- 18 years old had the UCL surgery, 19 out of 20 reported being satisfied with the surgery (17 were very satisfied, 2 were somewhat satisfied). Eighteen of the 19 satisfied patients (94.7 percent) reported that they returned to competitive baseball. Of the 19 players, three reported that their highest level of competition was in the minor leagues, another 13 went on to play intercollegiate baseball and three returned to high school baseball.

Overuse injuries account for nearly 50 percent of all sports injuries in middle school and high school students, according to the National Center for Sports Safety. For high school athletes whose growth plates have closed, this study shows that the "Tommy John" UCL reconstruction is a successful option for teenage baseball pitchers who need it.

While the trend of young athletes to specialize in one sport remains controversial, sports medicine has developed innovative surgeries to repair and reconstruct overuse injuries that can result from specialization. However, the bigger problem is prevention of injury. AOSSM and several other sports medicine organizations, including the American Academy of Orthopaedic Surgeons, American Medical Society for Sports Medicine, American Academy of Pediatrics, National Athletic Trainers' Association, National Strength and Conditioning Association and SAFE Kids USA have teamed together to help prevent overuse injuries in youth athletes. The STOP (Sports Trauma and Overuse Prevention) Sports Injuries campaign includes cutting edge information on sport specific injury prevention techniques for athletes, parents, coaches and healthcare providers.

For more details, visit www.STOPSportsInjuries.org.

Story Source:

Adapted from materials provided by American Orthopaedic Society for Sports Medicine.

Note: If no author is given, the source is cited instead.

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Scientists crack opium poppy's genetic code (AFP via Yahoo! News)

Posted: 14 Mar 2010 05:46 PM PDT

PARIS (AFP) – Researchers have discovered the genes that allow the opium poppy to make codeine and morphine, according to a new study.

The findings could lead to engineered plants and microorganisms that efficiently make codeine, one of the most widely prescribed painkillers in the world, the researchers said.

Unlike morphine, codeine cannot be easily converted to heroin.

"The enzymes encoded by these two genes have eluded plant biochemists for a half-century," said Peter Facchini, a professor at the University of Calgary in Canada and co-author of the paper.

"In finding not only the enzymes but also the genes, we've make a major step forward," he said in a press release.

Opium poppy remains the world's dominant source of codeine, morphine and another opiate called oxycodone, according to the study, published Sunday in Nature Chemical Biology.

In clinical medicine, morphine is often regarded as the drug-of-first-choice to relieve severe pain and suffering.

Codeine can be extracted directly from the opium plant, but mostly it is synthesised from the much more abundant morphine found in the opium poppy.

Most morphine produced for pharmaceutical use around the world is converted into codeine.

Once ingested, codeine is converted by an enzyme in the liver to morphine, which is the active painkiller and a naturally occurring compound in humans.

"With this discovery, we can potentially create plants that will stop production at codeine," said Facchini.

"Our discovery now makes it possible to use microorganisms to produce opiate drugs and other important pharmaceuticals."

Co-author Jillian Hagel, a post-doctoral scientist in Facchini's laboratory, used cutting-edge sequencing techniques to sift through some 23,000 different genes to find the one -- codeine O-dementhylase (CODM) -- that produces the plant enzyme which converts codeine into morphine.

"We have found the missing pieces that were needed to understand how the opium poppy makes morphine," she said.

The opium poppy has been grown and exploited for thousands of years for both its medicinal and mind-altering properties.

Morphine was isolated in the early 19th century, while codeine was first identified in 1832 by French chemist Pierre Robiquet.

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