ClockNews #38

Asleep or awake we retain memory

Sleeping helps to reinforce what we've learned. And brain scans have revealed that cerebral activity associated with learning new information is replayed during sleep. But, in a study published in the open access journal PLoS Biology, Philippe Peigneux and colleagues at the University of Liege demonstrate for the first time that the brain doesn't wait until night to structure information. Day and night, the brain doesn't stop (re)working what we learn.

The science of lost sleep in teens

"Some of our kids are literally sleep-walking through life, with some potentially serious consequences," Millman said. "As clinicians and researchers, we know more now than ever about the biological and behavioral issues that prevent kids from getting enough sleep. But the National Sleep Foundation did something powerful: They asked teens themselves about their sleep. The results are startling and should be a wake-up call to any parent or pediatrician."

Children who sleep less are three times more likely to be overweight

The less a child sleeps, the more likely he or she is to become overweight, according to researchers from Universit Laval's Faculty of Medicine in an article published in the latest edition of the International Journal of Obesity. The risk of becoming overweight is 3.5 times higher in children who get less sleep than in those who sleep a lot, according to researchers Jean-Philippe Chaput, Marc Brunet, and Angelo Tremblay. These results come from data collected among 422 grade school students aged 5 to 10. The scientists measured the weight, height, and waist size of each participant. Information on the children's lifestyle and socioeconomic status was obtained through phone interviews with their parents.

Sleep apnea treatment benefits the heart

Patients with obstructive sleep apnea have enlarged and thickened hearts that pump less effectively, but the heart abnormalities improve with use of a device that helps patients breathe better during sleep, according to a new study in the April 4, 2006, issue of the Journal of the American College of Cardiology.

Low Stairway to Heaven

SAD arises via fluctuation in melatonin, a chemical produced in response to darkness. Those with SAD suffer from depression during the winter, as the ratio of dark to light hours increases. Melatonin produces a certain drowsiness that causes your circadian rhythms to fall out of sync with the day-night cycles of the environment. Further, some research shows that darkness decreases serotonin levels, which negatively affects mood. Certain SAD sufferers find remedy in “light box treatment”—they expose themselves to artificial light for a few hours a day and become less depressed. I like to think of the steps as my own light box treatment—give me a few hours in front of Low and my mood dramatically improves.

Getting enough Zzzzzs? Kids often don’t

You can force a kid to bed, but you can’t make him fall asleep. Especially if he — or she — is a teenager. It’s not adolescent rebellion. It’s adolescent metabolism. They physically cannot fall asleep because their bodies’ internal clocks are on sort of a chronic daylight-saving time overdrive — which worsens through their teen years, ultimately tapering off in their 20s, according to Leigh Heithoff, clinical specialist with BryanLGH Medical Center West’s Department of Sleep Medicine.

What's holding up the sandman for so many of us?

Unfortunately, with the ease of writing and filling a prescription and the mostly good press these new drugs have gotten to date, millions of people are now taking them without first exploring the reasons for their sleep problems and possible nondrug routes to cure them.

Eye cells that don't see, but regulate

As any good high school biology student can tell you, the human eye sees light with special cells called rods and cones. But when George C. Brainard experimented with shining various colors of light into people's eyes, something odd happened: A specific shade of blue light was most effective at shutting down the body's production of melatonin - the "hormone of darkness" that helps regulate sleep and the body's internal clock. Yet that shade of blue is not one of the colors best detected by rods and cones. His conclusion, shared by others conducting studies on blind people and animals: There must be some unknown cells in the eye - some that responded to light but had nothing to do with seeing. Since that experiment at Thomas Jefferson University, reported in 2001, other scientists have indeed found the new cells, as well as the gene that controls them. Only in the last year has a consensus emerged about how the new cells work.

Sleep has become the new obsession

First it was looks, then weight. Now, the new Western obsession is sleep - or a lack of it. But even experts don't agree on how much people really need

Integrating Transcriptomics and Proteomics

An example of time-shifted discord would be that of the mammalian 24-hour circadian clock, in which regulatory proteins such as Period (mPER) exhibit a four- to eight-hour delay between protein and transcript expression.

Aging-Related Sex Dependent Loss of the Circulating Leptin 24-Hour Rhythm in the Rhesus Monkey

The adipocyte-derived hormone leptin plays a pivotal role in the regulation of body weight and energy homeostasis. Many studies have indicated that the circulating levels of leptin show a 24-h rhythm, but the exact cause and nature of this rhythm is still unclear. In the present study we remotely collected blood samples every h from young and old, male and female rhesus monkeys, and examined their 24-h plasma leptin profiles. In both the young males (10-11 yrs) and young females (7-13 yrs) a clear 24-h plasma leptin rhythm was evident, with a peak occurring ~4 h into the night and a nadir occurring ~1 h into the day (lights on from 0700-1900 h). A 24-h plasma leptin rhythm was also observed in the old males (23-30 yrs), even when they were maintained under constant lighting conditions (continuous dim illumination of ~100 lux). In marked contrast, plasma leptin concentrations were relatively constant across the day and night in old perimenopausal and postmenopausal females (17-24 yrs), regardless of the lighting schedule. These data establish that rhesus monkeys, like humans, show a daily nocturnal rise in plasma leptin, and show that the magnitude of this rhythm undergoes a sex-specific aging-dependent attenuation. Furthermore, they suggest that the underlying endocrine mechanism may be driven in part by a circadian clock mechanism.

Wake-Up Call for Sleep Tech

A bad night's sleep is reason for a very big business. Sleeping pills, led by Ambien, rack up more than $2 billion a year in the United States. Then there is the revenue from overnight stays at sleep clinics, over-the-counter pills, a parade of gimmicks and a thriving business for sleep specialists.
--------------
"Sleep is the new sex." So says psychologist Arthur J. Spielman, associate director of the Center for Sleep Disorders Medicine & Research at New York Methodist Hospital in Brooklyn, New York. "People want it, need it, can't get enough of it." The same could be said of profits. Spielman is co-author of The Insomnia Answer (Perigee Books, 2006). He is also developing light-delivering goggles that are supposed to help people reset the circadian rhythms that govern when they nod off and wake up, so they fall asleep faster and stay asleep longer. Sleep is also the new snake oil -- the promise of a good snooze from a book or a bed or a bottle. It's easy pickings.

I'm so tired of being tired

"I'm so tired," said my friend the last time we met for lunch. "The doctor said I have chronic fatigue."
She was not sleeping more than six hours a night, didn't find time to eat well or exercise, and was always achy, so it was not surprising that she felt exhausted. But now there was a label attached to her symptoms that made her feel depressed and alarmed.

CNN Presents Classroom: Sleep: A Dr. Sanjay Gupta Special

Set your VCR to record the CNN Special Classroom Edition: Sleep: A Dr. Sanjay Gupta Special when it airs commercial-free on Monday, April 17, 2006, from approximately 4:10 -- 5:00 a.m. ET on CNN. (A short feature begins at 4:00 a.m. and precedes the program.)

Lighting for the Aging Eye

In the bath, avoid fluorescents, Gilbertson advises. Instead, opt for 100-percent color rendering light bulbs, positioned on either side of your bathroom mirror. Consider installing a dimmer on bathroom lights. Research shows that very low-level regular light, or light in the red spectrum, maximizes night vision while minimizing the disruption of our circadian rhythm, Blitzer says.

Top tips to better sleep

One in three people get less than five hours of sleep a night, according to new research. But Dr John Shneerson, director of the Sleep Centre, Papworth Hospital, Cambridge, says just being aware of some simple tricks can help sleep sufferers achieve a good night's rest. "Sticking to regular bedtimes, helping the body to unwind and avoiding certain foods and drinks in the evening can induce drowsiness and enhance sleep," he says.

Ramelteon Showed Significant Reduction in Time to Fall Asleep With No Evidence of Rebound Insomnia or Withdrawal Effects

Results of a sub-analysis from a phase 3 clinical study showed that Rozerem™ (ramelteon) significantly reduced time to fall asleep in adults with chronic insomnia and showed no evidence of rebound insomnia or withdrawal effects.

Night shift: Late-night work can be bad for your health

According to studies done in the past five years by Harvard University, the National Cancer Institute and the Fred Hutchinson Cancer Research Center in Seattle, women who work the night shift have an increased risk of breast and colorectal cancer. These women have a 60 percent higher risk of breast cancer than women who have never worked nights, the research says. Because of the circadian rhythm -- the 24-hour cycle of sleep and wakefulness -- the body will never be fooled into thinking it's daytime when it's dark out. However, Attarian says there are people who over time can get used to the off-hours. Because of their genetic make-up, Attarian says, some people are just night owls.

Remodeling of astrocytes, a prerequisite for synapse turnover in the adult brain?

A stitch in time, it’s all in the mind

Time slows down in some Kung Fu movie sequences. Jet Li’s foot takes forever to land. Michelle Yeoh’s riposte is glacially slow. This showcases a state-of-the-mind technique called entering the zone: Tai chi masters say this enables aspirants to ‘go faster by going slower.’ While sceptics scoff at such paradoxes, scientists are discovering that, like biofeedback, humans may have more conscious control over their measurement and perception of time than previously thought. Some say this could even lead to chemical cues to shrinking eternity and stretching fleeting moments for those who want to throw away their watch and rock around the clock.

Bed Rest May Not Be Helpful for Threatened Miscarriage

An opinion piece in the March 24 issue of The New York Times highlights a controversial issue in obstetrics: the value of bed rest for threatened miscarriage. Although this intervention is widely prescribed, evidence of its efficacy is limited or absent, and some experts suggest that there may be deleterious effects.

Smart strategies that help you become a beautiful dreamer

Naps can be lifesavers, but if you overdo them, it may be tough to nod off during normal sleeping hours. And you don't want to nap for more than an hour or so at a stretch. "The problem is, when you start getting into two- or three-hour naps, you start resetting your circadian cycle," Dr. Hartse says. (That's your body's internal clock.)