Scientists at UC Berkeley have found that an afternoon nap improves cognition later in the day, and posit that the beneficial effects of a nap have to do with letting a particular area of the brain clear out short-term memory “storage space” so it can absorb new information.

To reach these conclusions, Matthew Walker and colleagues randomized 39 healthy adult volunteers into a nap group and a no-nap group.

The groups performed equally well on a midday test which involved absorbing a lot of facts. After that, the nappers retired for a 1.5 hour respite, while unfortunate souls in the no-nap group toiled away. Then,  at 6 pm, both groups underwent further cognitive testing.

The scientists found that the nappers outperformed the non-nappers. In fact, the nappers performed better than they did on the first test, which occurred before their nap.

The results supported earlier research which showed that that the hippocampus temporarily stores fact-based memories before relaying them to the brain’s prefrontal cortex, and that the hippocampus has a relatively limited storage capacity.

They also supported earlier research showing that students who work through the night reduce their capacity to absorb new facts by 40% by the following morning.

According to Walker, “Sleep not only rights the wrong of prolonged wakefulness but, at a neurocognitive level, it moves you beyond where you were before you took a nap.”

Walker’s group also demonstrated using EEGs that the memory-refreshing process occurs during stage 2 non-REM sleep (non Rapid Eye Movement sleep). This is why, Walker suggests, humans spend nearly half their nap time in this stage of sleep.

Walker presented these preliminary findings at last month’s annual meeting of the American Association of the Advancement of Science (AAAS) in San Diego.

The obesity epidemic has become a major public health concern. The phenomenon is typically attributed to changes in diet and lifestyle, and socioeconomic factors like poverty and poor education.

Genetic factors have been known play a role as well, but a recent study by UK-based scientists suggests they play much more prominent role, at least in a subset of people who become morbidly obese at a young age.

In the study, Sadaf Farooqi of the University of Cambridge and colleagues showed that many such kids are missing a large chunk of DNA, known as SH2B1, from chromosome 16.

The missing genetic code had been known to play a role in regulating weight and blood sugar levels. Kids with the chromosomal abnormality tended to overeat on a massive scale, and gain weight easily. 

To reach these conclusions, the scientists scanned the genomes of 300 morbidly obese kids in search of copy number variants (CNVs), which are lengthy strands of DNA that are either duplicated or missing.
The scientists compared their findings with information from healthy controls.

In their write-up, which appears in Nature, the scientists wrote, “we identified several rare copy number variants that were recurrent in patients but absent or at much lower prevalence in controls.”

“Part of chromosome 16 can be deleted in some families. People with this deletion have severe obesity from a young age,” Farooqi told Medical News Today: “One particular gene on chromosome 16 called SH2B1 plays a key role.”

The finding may have broad social implications, since it is common to blame parents or guardians for morbid obesity in kids. The scientists noted for example, that some kids in the study had been handed over to Social Services because their parents were assumed to have been deliberately overfeeding them.

Young adults may be putting themselves at increased risk of unplanned pregnancies and sexually transmitted diseases (STDs) during the upcoming holiday period, according to new independent research conducted by YouGov and published on the Web site of UK-based Marie Stopes International.

Nearly half (48%) of respondents aged 18-34 stated that they drink more alcohol during the holidays than at other times of the year, and 27% admitted having unprotected sex because they were too drunk to remember to use contraception.

In response, Marie Stopes has launched a ‘Wrap it Up’ campaign that urges men and women to carry condoms and practice safe sex during the holidays.

Marie Stopes’ UK centers are also offering an emergency contraceptive pill  (which can be taken up to 3 days after unprotected sex to terminate unwanted pregnancies) at the reduced price of £10 until January 31st 2010 or while stocks last.

The research also showed that of the 18-34 year olds questioned:

- 19% had sex with someone they just met due to the influence of alcohol at a holiday party,
- 45% had sex under the influence of alcohol with someone that they wouldn’t have, had they been sober,
- 41% had sex that they regretted the morning after.

“The combination of alcohol and the festive party spirit may reduce inhibitions, and lead men and women to make decisions about their sexual behavior that they may not have made if sober,” said Lindsay Davey, Sexual Health Nurse at Marie Stopes. “In January and February last year Marie Stopes’  UK centers saw greater numbers of women seeking abortion services than at any other time of the year.”

Fourteen years ago, Harvard researchers revealed that insurance companies were big-time investors in tobacco companies. The seemingly hypocritical position prompted outrage and calls for them to divest.

But when the same scientists recently re-examined the matter, they found the industry had failed to kick the habit.

By reviewing SEC filings and news reports from 2008, J. Wesley Boyd and colleagues determined that US, UK and Canadian-based insurance companies owned at least $4.4 billion worth of stock in companies whose subsidiaries produce cigarettes, cigars, chewing tobacco and related products.

“Despite calls upon the insurance industry to get out of the tobacco business by physicians and others, insurers continue to put their profits above people’s health,” Boyd told Medical News Today. “It’s clear their top priority is making money, not safeguarding people’s well-being.”

The World Health Organization estimates that tobacco products contribute to 5.4 million deaths per year worldwide.

New Jersey-based Prudential Financial Inc., which markets life and disability insurance, has holdings in tobacco firms like Reynolds American and Philip Morris, that total $264 million.
 
These numbers are dwarfed by Toronto-based Sun Life which sells health, disability, life and long-term care insurance. It owns just north of $1 billion in tobacco company stock.

Meanwhile, London-based Prudential Plc, which offers disability, health and long-term care insurance, holds $1.38 billion in British American Tobacco and other such companies.

“Insurance firms have figured out ways to profit from both… investing in tobacco (and) selling life or health insurance. (They) exclude smokers from coverage or, more commonly, charge them higher premiums. Insurers profit -- and smokers lose -- twice over,” wrote the authors.

Boyd’s group first reported on the matter in a 1995 Lancet article.

Over 185 million Americans live under skies so polluted it endangers life, according to a report released last week by the American Lung Association.

The report grades 900 US counties on an A to F scale for ozone (smog), annual particle pollution, and 24-hour particle pollution.

Cities ranking in the top 3 on ozone pollution were the Los Angeles-Long Beach-Riverside metropolitan area, Bakersfield and Visalia-Porterville.

The three cities also top the charts for year-round particle pollution, and follow just behind Pittsburgh-New Castle at the top of the list on 24-hour particle pollution.

Fargo, North Dakota came up cleanest in all categories.

“60% of Americans are breathing air dirty enough to send people to the emergency room, to shape how kids’ lungs develop, and to kill,” said ALA Chairman Stephen Nolan.

The ALA report indicates that 175 million Americans live in areas where there is a dangerous abundance of days in which unhealthy ozone levels are present. Ozone irritates the lungs like a bad sunburn. It triggers asthma and shortens life expectancy.

Particle pollution is the “most dangerous and deadly of the outdoor air pollutants,” according to the ALA, because it “can increase the risk of early death, heart attacks, strokes and emergency room visits for asthma and cardiovascular disease.”

One in 6 Americans lives in an area having unhealthy level of year-round fine particle pollution, and 30% reside in counties with unhealthy 24-hour levels, in which atmospheric fine particle concentrations spike to unhealthy levels for hours or even days.

“Air pollution can impair the lung function of even the healthiest people,” said Norman Edelman, the ALAs Chief Medical Officer, but “people with lung and heart disease (are) especially vulnerable,” he added.

Scientists at SUNY Downstate have demonstrated that injecting a compound known as ZIP into the brains of mice causes them to instantly forget distasteful memories, raising hope the stuff could someday be used to treat humans with PTSD or drug addiction.

Todd Sacktor and colleagues made the discovery after deducing that a substance known as PKMzeta was involved in murine memory.

Sacktor’s group found for example, that when neurons in the hippocampus and neocortex of mice were activated by a certain memory, they released PKMzeta to recruit nearby neurons. This apparently helped the brain construct visual, auditory and olfactory components of that particular experience.
 
These PKMzeta molecules subsequently remained at their new locations, effectively hard-wiring the memory for easy recall at a later time.

Sacktor’s group then leveraged work by André Fenton, a colleague at SUNY Downstate, who had devised a technique for generating powerful spatial location memories in mice such as the position in a chamber where they could expect to receive an electric shock.

Once Fenton’s mice learned the avoidance behavior, they didn’t forget, at least until Sacktor nailed ‘em with a short, sharp, shot of ZIP. Almost instantly thereafter, the mice behaved as if they had completely forgotten the lesson.

“If this molecule is as important as it appears to be, you can see the implications,” Sacktor told the New York Times. “For trauma. For addiction, which is a learned behavior. Ultimately for improving memory and learning.”

But Thomas Carew, a neuroscientist at UC Irvine was circumspect. “There is not going to be one, single memory molecule, the system is not that simple,” he said. “There are going to be many molecules involved, in different kinds of memories, all along the process of learning, storage and retrieval.”

Christakis and Fowler are at it again!

Two months ago they caused a stir by publishing research in BMJ which seemed to show that happiness is contagious, a conclusion that some chalked up to an inexcusably naïve failure to recognize the effects of epiphenomena in social networks.

Now these crowd pleasers have put a piece in PNAS which concludes that a person’s popularity is genetically determined. 

Or as Christakis, a medical sociologist at Harvard told Medical News Today, “We were able to show that our particular location in vast social networks has a genetic basis.”

“In fact, the beautiful and complicated pattern of human connection depends on our genes to a significant measure,” he waxed.

Does this guy think he’s Ram Dass or what?

To reach this data-mining epiphany, Christakis and Fowler characterized the social networks of 1,110 identical and non-identical teen-aged twins from the National Longitudinal Study of Adolescent Health.

They measured popularity by the number of times an individual was named as a friend and the likelihood those friends knew each other.

Does this work for everybody?

Whatever, the scientists observed a higher concordance among the networks of identical twins than their non-identical counterparts.

They also concluded that whether a person was central to, or at the periphery of her social network was genetically determined, which inspired them to raise Charles Darwin from the dead, all in the same article.

Maybe it’s good to be on the periphery of a social group, they mused, like when there’s Ebola virus floating around. Then again, those hub-of-the-network types have access to more information like which Starbucks still has Christmas Blend in stock.
 
Please people.

It’s a shame that blood pressure recordings from the doctor’s office aren’t great predictors of future cardiovascular events due to white-coat hypertension, but it is what it is.

The long-recognized phenomenon is characterized by office-based BP readings that are higher and more labile than those taken during the course of normal everyday life.

Thankfully, scientists have shown that ambulatory blood pressure recording devices provide useful predictive information, particularly in those having severe hypertension, a cardiac history, multiple cardiovascular risk factors, pregnancy and elderly folks.

Now Gil Salles and co-investigators at University Hospital Clementino Fraga Filho in Rio de Janeiro, Brazil have shown that ambulatory blood pressure recordings can predict CV risk in another subset of patients, the ones with resistant hypertension.

Sales’ was a prospective study of 556 patients with resistant hypertension, defined as persistently elevated blood pressure despite treatment with 3 anti-hypertensive agents.

After median follow-up of 4.8 years, the scientists found that 109 patients (19.6%) either died or incurred a cardiovascular event.

After controlling for age, gender, prior cardiac events and other CV risk factors, Salas’ group confirmed that office-derived blood pressure recordings were not predictive of future events, but higher mean ambulatory BPs did predict these events.

Ambulatory systolic and diastolic blood pressure recordings were both effective predictors, and nighttime recordings were superior to those obtained during the day.

Britain’s National Institute for Health and Clinical Excellence (NICE) new treatment guidelines for attention-deficit hyperactivity disorder (ADHD) suggest that drugs should be used as first line therapy only for those who are severely impaired.

British physicians are strongly encouraged to implement the NICE recommendations, but they are not obligated to do so. Widespread adoption of the new guidelines would result in dramatic reductions in the use of Ritalin (Novartis) Concerta (Johnson & Johnson) and Strattera (Eli Lilly).

The NICE recommendations call for group-based parent education and training programs as the first line intervention for children with mild or moderate impairment due to ADHD. These behavioral/social interventions are also recommended, along with drug therapy, for severe cases.

NICE also stated that primary care physicians should neither diagnose ADHD nor start drug treatment on their own. These decisions should be left with psychiatrists, pediatricians or those having expertise in ADHD.

Approximately 3% of all school aged children are thought to have ADHD, but only a small percentage of them are severely impaired. In the US, more than 2.5 million children take drugs for ADHD.

A randomized controlled trial has revealed that for patients with osteoarthritis (OA) of the knee, arthroscopic surgery offers no benefit versus conservative therapy.

The arthroscopic intervention tested in this study is lavage and debridement. Conservative therapy included anti-inflammatory medications and physical therapy.

The investigators randomized 178 patients with moderate to severe OA. They assessed patient outcomes using two symptom-based questionnaires-the Western Ontario and McMaster Universities Osteoarthritis Index and the Short Form-36 Physical Component summary score. When investigators compared scores on these tests for the treatment and control groups at the end of two years, they found no significant difference. In particular, there was no difference in pain or activity level. Score comparisons at earlier time intervals also showed no difference.

The authors concluded that “the resources currently allocated towards arthroscopic surgery for osteoarthritis would be better directed elsewhere.”

Interestingly, Medicare stopped paying for the procedure in 2003 after an earlier study had come to the same conclusion, despite protests from many surgeons who felt the trial design was flawed. It is not clear how many arthroscopic surgeries for OA had been done between then and now (and presumably billed for using a reimbursable procedure code), but the number is probably in the hundreds of thousands per year.