Friday, August 12, 2005

ClockNews #33

Lag Drag

As motivational speaker and humorist Linda Perret once said, "Jet lag is nature's way of making you look like your passport photo."

Nighttime risk for newborns

While the superstitious might attribute the difference to astrology, numerology or perhaps even circadian rhythms, Gould said hospitals are the primary suspects. "There may be some hospitals that are really stressed at night in being able to meet patients' needs," he said.

Stuff dreams are made of

The National Institutes of Health have identified teens and young adults 12 to 25 as a population at high risk for problem sleepiness. In addition to poor performance at work or school, sleepiness leads to injuries and deaths from accidents. Drivers under 25 are involved in more than half of all fall-asleep crashes. Sleep deprivation also is linked to depression and might be a factor in attention deficit disorder.

That Morning Workout Could Be Fatal

Early morning joggers, swimmers and fitness fanatics who use the gym before breakfast are putting themselves at greater risk of infections than evening exercisers, scientists now claim.

Sex-based physiology prior to political correctness

Readers of this classic paper will immediately notice differences in the structure of that paper compared with reports of today. One obvious difference between the two groups of papers separated by almost half a century is the minimalistic statistical analysis of the data. Unlike requirements for some journals today for "independent statistical review," statistics of the Critchlow study were described with one sentence: "All statistical probabilities were derived from analysis of variance." Figures and text, unlike today's papers, were not peppered with the prerequisite asterisks, crosses, and P values to the nth decimal level of statistical significance. Differences between responses of male and female animals are obvious to the reader and as such emphasize that statistics are a tool, like other scientific assays, and statistical significance should not override common sense.

A second difference between papers of today and the Critchlow study is the lack of translational relevance or applied rationale for the study. In a recent interview with Dr. Critchlow, he indicated that his group simply needed reliable baseline information from which to design future experiments. Although their investigative team had considered possible clinical relevance of their observations, he and his colleagues were simply not aware of any. Needless to say, observations from these basic experiments have clinical relevance today. Indeed, it has taken over 40 years for sexual dimorphic responses to cortisol to be observed and validated in pubertal humans (10), and today it is recognized that estrogen-modulated release of ACTH has implications for sex disparities in incidence of depression, reproductive disorders (4), and perhaps acute stress-induced Tako-Tsubo cardiopathy (1).

By today's standards, the study by Critchlow and colleagues could perhaps be labeled "descriptive," an adjective that often pronounces a death sentence for publication of papers in so-called "high-impact" journals. Fortunately, physiologists recognize the value of definitive, descriptive, integrative experiments that provide insight into controversial findings. It is just such descriptive observations that are still cited after 40 years (9) because they provide the background information that is necessary to explore more mechanistic approaches to understanding how physiological systems are modulated.

In the Dark

Night-shift workers can feel isolated, hostile -- and just plain tired

It's when you don't snooze that you can lose

Failing to get the proper amount of sleep can raise the risk of serious health problems and experts often recommend getting eight hours each night. But the exact amount of sleep you need depends on many factors.

We're only human, none of us made to run like machines

It's hard to believe that not long ago, most people actually went to bed when the sun went down and got up when the sun came up.

Sleepless nights may cause ulcer

Researchers in the UK have discovered that the protein TFF2, which aids in stomach lining repair, mostly acts during the night when we sleep.

Faulty Biological Clocks May Influence Addiction

A gene that regulates the body's circadian rhythms, including sleep and wakefulness, body temperature, hormone levels, blood pressure and heart activity, may also play a central role in drug addiction, according to a recent study published online by the Proceedings of the National Academy of Sciences (PNAS).

Drug helps for staying awake

For those battling the fatigue of working the graveyard shift, a new study suggests that a prescription drug approved for narcolepsy may reduce sleepiness and improve alertness for nocturnal employees.

Drug may help night-shift workers

Working at night and sleeping during the day is not natural for any human body, but some people have trouble adapting to such arrangements to the point where their distress qualifies as a medical disorder. Now, this underdiagnosed and difficult-to-treat condition is the subject of the first-ever clinical trial of the promising medication modafinil.

Teens Should Light Up - Their Glasses, That Is

Researchers say teens should wear orange tinted glasses on their way to school to reset their internal clocks.

Researchers catch up with the causes of jet lag

What that means, he says, is it is not just a matter of the whole body being out of time in the environment. It is as if the times of all the body's subclocks are out of sync as well.

New England Journal of Medicine Publishes First Clinical Study of Medication to Improve Wakefulness in Patients with Shift Work Sleep Disorder

"This is a very important first study demonstrating the value of an effective therapy for shift work sleep disorder and illustrates the need for further research to identify other effective therapies for these patients, whose sleepiness was not completely resolved with treatment," stated Charles A. Czeisler, PhD, MD, Professor of Sleep Medicine at Harvard Medical School and lead study author. "Patients with this under-recognized condition are just as sleepy at night as patients with narcolepsy or obstructive sleep apnea during the day."

Provigil of Modest Benefit for Shift-Work Sleep Disorder

3-Provigil (modafinil), a stimulant with an unknown mechanism, has been found to be of modest benefit in treating excessive sleepiness associated with shift-work sleep disorder, yet more effective therapies are needed, researchers here reported.

The Papalotzin Panopticon

Scientists only recently sorted out a major butterfly mystery: how Monarch butterflies have steered for millennia between eastern Canada's forests and central Mexico's mountains. It was known that the Monarchs use the angle of polarized sunlight to keep them on course, but researchers have discovered the mechanics of how this works. Special photoreceptors for ultraviolet light in butterfly eyes provide them with sense of direction. This sense connects with the circadian clock in the butterfly brain to both cue the creatures and direct them on their 3,400-odd mile migration.

Sleep Demons

Students can find their nightly rest interrupted by insomnia and sleeptalking

P.M. kids in an A.M. world

Why are teens so foggy early in the day?

Sleep Aid with Novel Mechanism Approved

A new insomnia treatment, approved by FDA July 22, is the first insomnia drug that was not designated a controlled substance by the Drug Enforcement Agency. Rozerem (ramelteon) is also the second sleep aid indicated for long-term use. Sepracor’s Lunesta (eszopiclone) was the first.

Protein controls metabolism and circadian rhythms

University of Toronto researchers have gained new insight into how a specific protein may control circadian rhythms and metabolic processes, which has implications for treating cholesterol-related diseases.

Sleep deprivation eats into child development

A sleep-deprived child may appear the opposite of sleepy -- so much so that he or she could end up being wrongly diagnosed with an attention deficit disorder

Melatonin Slows Cancer But Is Little Used

Despite growing evidence that melatonin significantly improves risk, survival, and performance status in patients with advanced cancer, it continues to be overlooked as a therapeutic option because it lacks US Food and Drug Administration (FDA) approval and requires administration at times of day inconvenient to physicians.

Teenager circadian rhythm

Many teens have trouble waking up in the morning for school, and their circadian clock may be to blame.

New insight into how protein E75 may control circadian rhythms and metabolic processes

University of Toronto researchers have gained new insight into how a specific protein may control circadian rhythms and metabolic processes, which has implications for treating cholesterol-related diseases.

Dad Knows Best Sometimes

All people follow a “body rhythm” that has them up at a particular time each morning, and bedding down at another particular time each night.

Age and sleep play catch-up

There's growing evidence that poor sleep can foster diseases that shorten life, says Fred Turek, director of the Center for Sleep and Circadian Biology at Northwestern University School of Medicine. Sleep problems can lead to biological changes that cause weight gain, increase diabetes risk, promote heart disease and worsen depression.

Putting Some Life Back into the Graveyard Shift

Imagine waking up every day at 9PM and heading to work until 3AM. Would you be able to adapt to working nights and sleeping when the sun is up? There's a reason they call it the graveyard shift, but for the 22 million shift workers in America, overnight jobs and constantly changing schedules are a reality that cannot be avoided.

Sleep, and other maladies

Sleep deprivation seems to be a favorite means of torture. Considered non-invasive, it still leaves scars on the psyche. Our circadian rhythms are disrupted, and this affects more than the body, as any medical student can affirm. Sleepless nights, whether in Seattle or not, can mean a terrible day. Polyphasic sleep, or short siestas can help ease the tiredness.

Drug treatment mimics circadian rhythms

UK company Diurnal has received orphan product designation from the European Commission for a novel treatment that uses a drug delivery technology to match the body’s circadian rhythms.

Battle against cancer hits home for project donor

How disruption to the body's circadian clock may be related to breast cancer development, and how the circadian clock may offer new ways to fight cancer.

Window treatments control light, privacy

Light is essential to life. Without light, there would be no life as we know it in our world. It's important not just for the plants in our home and garden, but also for our own emotional and physical health. Many people suffer from seasonal affective disorder when they are deprived of natural light during winter months.

Plant Circadian Clocks Increase Photosynthesis, Growth, Survival, and Competitive Advantage

Circadian clocks are believed to confer an advantage to plants, but the nature of that advantage has been unknown. We show that a substantial photosynthetic advantage is conferred by correct matching of the circadian clock period with that of the external light-dark cycle. In wild type and in long– and short–circadian period mutants of Arabidopsis thaliana, plants with a clock period matched to the environment contain more chlorophyll, fix more carbon, grow faster, and survive better than plants with circadian periods differing from their environment. This explains why plants gain advantage from circadian control.

Hormone melatonin may slow breast cancer: study

A new study is shedding more light on the possible link between breast cancer and lower levels of melatonin -- a hormone the body produces during darkness to help promote sleep.

Jennie Brand-Miller: GI Jennie

It may feel as though GI has all the hallmarks of this year's media hype. The health and lifestyle pages are forever reinventing themselves, and now everyone is sick to death of the Atkins and South Beach diets, they have hit upon GI as the Next Big Thing. But that's not quite the reality. The media may operate according to its own circadian rhythms and GI may fade from the public consciousness, but the hard science behind it dates back nearly 25 years and Brand-Miller has been in on it from the start.

Workbrain Unveils Real-Time Self-Scheduling for Healthcare

Workforce management innovator enables healthcare organizations to improve patient care while decreasing costs

Neurobiology of Mice Selected for High Voluntary Wheel-Running Activity

Selective breeding of house mice has been used to study the evolution of locomotor behavior. Our model consists of 4 replicate lines selectively bred for high voluntary wheel running (High- Runner) and 4 bred randomly (Control). The major changes in High- Runner lines appear to have taken place in the brain rather than in capacities for exercise. Their neurobiological profile resembles features of human Attention Deficit Hyperactivity Disorder (ADHD) and is also consistent with high motivation for exercise as a natural reward. Both ADHD and motivation for natural rewards (such as food and sex), as well as drugs of abuse, have been associated with alterations in function of the neuromodulator dopamine, and High-Runner mice respond differently to dopamine drugs. In particular, drugs that block the dopamine transporter protein (such as Ritalin and cocaine) reduce the high-intensity running of High- Runner mice but have little effect on Control mice.

Nuns carve pioneering life from the land

New Skete is more sensitive to people's circadian rhythms than many monasteries. There is no specific time for the sisters to read, pray or meditate, other than matins in the morning and vespers, at 5 p.m.

Woman Receives Chemotherapy While Rollerblading on Lakefront

McConnell received her chemotherapy via a new field of medicine, called chronotherapy. The term is from the Greek chronos, meaning time. Chronotherapy is medicine that takes the body"s natural rhythms into account.

Parasites' genetic code 'cracked'

Sleeping sickness disturbs a person's circadian rhythm so they stay awake at night and sleep during the day.

Around the clock

There's a good amount of research that has found human circadian rhythm favors a light/dark cycle, meaning that people are built to be up during the day and to sleep at night. At the very least, a nocturnal job challenges the way many people have been raised to live and work.

Scientists find clues to memory health

They wrote in the July 2005 issue of the Journal of the American Geriatric Society that senior adults have more difficulty getting a good night's sleep because the body's circadian rhythms change with age. Seniors also may experience insomnia as a side effect of one of the many medications prescribed to older adults.

Nuclear import of mPER3 in Xenopus oocytes and HeLa cells requires complex formation with mPER1

Several transcription factors with the function of setting the biological clock in vertebrates have been described. A detailed understanding of their nucleocytolasmic transport properties may uncover novel aspects of the regulation of the circadian rhythm. This assumption led us to perform a systematic analysis of the nuclear import characteristics of the different murine PER and CRY proteins, using Xenopus oocytes and HeLa cells as experimental systems. Our major finding is that nuclear import of mPER3 requires complex formation with mPER1. We further show that the nuclear localization signal (NLS) function of mPER1 and not activation of a masked NLS in mPER3 is critical for the import of the mPER1–mPER3 complex. Finally, and as previously described in other cell systems, nuclear import of mPER proteins in Xenopus oocytes correlates positively with their phosphorylation.

Serotonin may play a role in maintaining circadian rhythm

Researchers at the University of Pennsylvania School of Medicine have determined how serotonin decreases the body's sensitivity to light and that exposure to constant darkness leads to a decrease in serotonin levels in the brain of fruit flies.

Mood Lighting: Penn Researchers Determine Role Of Serotonin In Modulating Circadian Rhythm

Researchers at the University of Pennsylvania School of Medicine have determined how serotonin decreases the body's sensitivity to light and that exposure to constant darkness leads to a decrease in serotonin levels in the brain of fruit flies. These findings suggest that serotonin may play a role in maintaining circadian rhythm, as well as modulating light-related disorders such as seasonal affective disorder (SAD). Senior author Amita Sehgal, PhD, Professor of Neuroscience at Penn and a Howard Hughes Medical Institute (HHMI) Investigator, and colleagues report their findings in the July 7 issue of Neuron.



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