Alcohol interferes with body's ability to regulate sleep

At right: Mahesh Thakkar, PhD, associate professor and director of research in the MU School of Medicine’s Department of Neurology, and Pradeep Sahota, MD, chair of the MU School of Medicine’s Department of Neurology, have studied alcohol’s effects on sleep for more than five years. Their study found that drinking interferes with the brain’s built-in system for regulating a person’s need for sleep. Credit: Image courtesy of University of Missouri-Columbia

Researchers from the University of Missouri School of Medicine have found that drinking alcohol to fall asleep interferes with sleep homeostasis, the body's sleep-regulating mechanism.

Alcohol is known to be a powerful somnogen, or sleep inducer, and approximately 20 percent of the U.S. adult population drinks alcohol to help fall asleep. The researchers, led by Mahesh Thakkar, PhD, associate professor and director of research in the MU School of Medicine's Department of Neurology, have studied alcohol's effects on sleep for more than five years. They found that alcohol interferes with the brain's built-in system for regulating a person's need for sleep.

"The prevailing thought was that alcohol promotes sleep by changing a person's circadian rhythm -- the body's built-in 24-hour clock," Thakkar said. "However, we discovered that alcohol actually promotes sleep by affecting a person's sleep homeostasis -- the brain's built-in mechanism that regulates your sleepiness and wakefulness."

Sleep homeostasis balances the body's need for sleep in relation to how long a person has been awake. If an individual loses sleep, the body produces adenosine, a naturally occurring sleep-regulating substance that increases a person's need for sleep. When a person goes to sleep early, sleep homeostasis is shifted and he or she may wake up in the middle of the night or early morning. The researchers found that alcohol alters the sleep homeostatic mechanism and puts pressure on an individual to sleep. When this happens, the sleep period is shifted, and a person may experience disrupted sleep.

"Based on our results, it's clear that alcohol should not be used as a sleep aid," said Pradeep Sahota, MD, chair of the MU School of Medicine's Department of Neurology and an author of the study. "Alcohol disrupts sleep and the quality of sleep is diminished. Additionally, alcohol is a diuretic, which increases your need to go the bathroom and causes you to wake up earlier in the morning."

In addition to studying alcohol's impact on sleep homeostasis, the researchers explored how alcohol withdrawal affects sleep. The investigators found that after extended periods of frequent drinking, subjects would fall asleep as expected, but would wake within a few hours and would be unable to fall back asleep. When the subjects were not given alcohol, the researchers found that subjects showed symptomatic insomnia.

"During acute alcohol withdrawal, subjects displayed a significant increase in wakefulness with a reduction in rapid eye movement and non-rapid eye movement sleep," Thakkar said. "This caused insomnia-like symptoms and suggests an impaired sleep homeostasis."

The researchers hope to use these findings to explore other effects of alcohol consumption.

"Sleep is an immense area of study," Thakkar said. "Approximately one-third of our life is spent sleeping. Coupled with statistics that show 20 percent of people drink alcohol to sleep, it's vital that we understand how the two interact. If you are experiencing difficulty sleeping, don't use alcohol. Talk to your doctor or a sleep medicine physician to determine what factors are keeping you from sleeping. These factors can then be addressed with individualized treatments."

The study, "Alcohol Disrupts Sleep Homeostasis," is an invited article published in the international biomedical journal Alcohol.

Source:  University of Missouri-Columbia

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Artificial light, biological clock disruptions, increase breast cancer risk, study finds

Employment as a flight attendant has been found to be related to an increased risk of breast cancer. Credit: © dmitrimaruta / Fotolia

The disruption of a person's circadian rhythm -- their 24-hour biological clock -- has been linked to an increased risk of breast cancer, according to new University of Georgia research. The culprit, in this study in particular, is artificial light.

"Exposure to artificial light leads to a significantly higher risk for developing breast cancer," said Chunla He, a biostatistics graduate student in the UGA College of Public Health. "To decrease the use of artificial light, people should avoid working at night and implement earlier bed times."

Her research, published in the International Archives of Occupational and Environmental Health, examined key studies that included risk factors for developing breast cancer.

"A large body of related research about circadian rhythms and breast cancer exists," He said. 

"However, these studies are inconsistent and have a variety of limitations."

Under the mentorship of Sara Wagner Robb, assistant professor of epidemiology in the College of Public Health, He turned to previous studies to see what the research revealed.

In addition to other relevant exposures, He examined studies on breast cancer and flight attendants, who typically work both day and night shifts. The flight attendants represented a group of workers particularly susceptible to disrupted circadian rhythms, which are heavily influenced by light.

In her analysis, He found that employment as a flight attendant was related to an increased risk of breast cancer.

"People naturally secrete the hormone melatonin, which helps to regulate the circadian rhythm," He said. "When the sleep-wake cycle is disrupted by artificial light, melatonin secretion is adversely affected."

Robb recommends spreading this information to shift workers so they understand the harms in disrupting their circadian rhythms.

"Individuals engaging in this type of work should be aware of these risks and may make efforts to adjust their circadian rhythms," she said. "Although additional studies are certainly needed, scientists are becoming increasingly aware of the health risks associated with night workers and others exposed to circadian-disrupting behaviors."

Robb and He also advise that future research needs to examine social constraints -- which may foster disruption of circadian rhythms -- on shift workers. Additionally, shift workers should contact their primary care physicians for personalized treatment and options.

"This information tells us the harm in disrupting our natural cycle," He said. "With this new analysis, we must be cautious in our exposure to artificial light."

The article was co-authored by Sonia Taj Anand, a former graduate student in the College of Public Health; Mark H. Ebell, professor of epidemiology; and John E. Vena, Medical University of South Carolina.

Source: University of Georgia

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Internet addicts often suffer from additional disorders

Chatting via WhatsApp rather than meeting friends in real life, sharing holiday photos on Facebook rather than showing them in person, playing video games rather than going out. Digital media play an important role in our everyday lives. However, some people spend an excessive amount of time online, and they are unable to break free. Credit: Image courtesy of Ruhr-Universitaet-Bochum

Internet addicts often suffer from concomitant disorders, most frequently from depressive disorders, anxiety disorders and ADHS. PD Dr med. Bert te Wildt studies this phenomenon at the Ruhr-Universität's LWL Clinic for Psychosomatic Medicine and Psychotherapy.

Spectrum of concomitant disorders similar to that in alcohol addicts

The researcher from Bochum has compiled a so-called comorbidity profile of 25 Internet addicts. Each patient presented at least one concomitant disorder. Together with his colleagues, Bert te Wildt examined 25 alcohol addicts for comparison. Their comorbidity profile was quite similar. However, only every other patient in this cohort suffered from a concomitant disorder. "These results highlight the significance of comorbidity for Internet addiction," says te Wildt. He also points out: "This is not a one-way street, the disorders interact." In another study, he found evidence that in a number of patients Internet addiction may be traced back to similar personality structures.

Large numbers presumably undetected

According to estimates, 500,000 Germans in the age bracket from 14 to 64 years suffer from Internet addiction, which most commonly takes the shape of online gaming addiction. The studies conducted by Bert te Wildt's team at the media outpatient clinic in Bochum suggest that many cases remain undetected.

Source: Ruhr-Universitaet-Bochum

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Software to automatically outline bones in x-rays

An image from the Bone Finder software. Credit: Image courtesy of Manchester University

Research into disorders such as arthritis is to be helped by new software developed at the University of Manchester which automatically outlines bones -- saving thousands of hours of manual work.

Amidst a national shortage of radiographers in the UK and an increasing requirement for researchers to work with large databases of radiograph images, the software which is being funded by the Engineering and Physical Sciences Research Council, is being designed to automatically pick out the shapes of bones in the images, rather than relying on individual researchers.

The system can already identify hips, but the researchers from the University's Institute of Population Health will now adapt it to map out knees and hands and to be able to learn to identify other bones and structures within the body.

The funding will allow further development to ensure the system is accurate enough that it can be used in hospitals to help provide faster diagnosis of problems in patients.

Professor of Computer Vision, Tim Cootes said: "Mapping the outlines of bones from radiographs is hard work that takes time and skill. When researchers into conditions like arthritis are working with hundreds of images, it's a very inefficient way of obtaining data.

"The idea of this software is to take the routine tasks out of human hands, so scientists can 

focus on drawing conclusions and developing treatments."

The funding of £300,000 lasts for three years and builds on earlier work which developed software, called Bonefinder, to identify problems and find the outlines of hips. This free software has been adopted by a number of research groups, including some based in Oxford and California.

Professor Cootes added: "We have a growing problem with arthritis which affects more than 30% of over 65s and costs around £30 billion to the UK economy year.

"Ultimately we want to get this technology into hospitals where it can save time and resources for the benefit of patients."

Source: Manchester University

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Odor that smells like blood: Single component powerful trigger for large carnivores

African wild dogs compete for a log impregnated with blood or a single component. Both were equally attractive. Credit: Linköping University

People find the smell of blood unpleasant, but for predatory animals it means food. When behavioural researchers at Linköping University in Sweden wanted to find out which substances of blood trigger behavioural reactions, they got some unexpected results.

Matthias Laska is professor of zoology, specialising in the sense of smell. For some time his focus has been on scents that directly affect the behaviour of animals.

"For predators, food scents are particularly attractive, and much of this has to do with blood. We wanted to find out which chemical components create the scent of blood," he says.

The study, conducted at Kolmården Wildlife Park, found that for the animals, one particular component of blood odour was just as engaging as the blood odour itself.

"It's a completely new discovery that raises interesting questions on evolution," says Prof Laska.

The study has been published in the scientific journal PLOS ONE.

When Prof Laska did a search for the contents of volatile substances in mammalian blood, he found nothing. Human blood has been analysed for disease markers, but we have very little information on the substances that give blood its characteristic scent.

A master's student was sent to Friedrich-Alexander-Universität in Erlangen Germany, to analyse mammalian blood with the help of gas chromatography and mass spectrometry, methods used for separating and identifying chemical compounds in a sample. The machine detected some 30 substances, of which some are decomposition products from fats. But the machine lost the job to the human scent experts who had also been engaged. They identified scents that the gas chromatograph missed completely.

One substance stood out: an aldehyde called trans-4,5-epoxy-(E)-2-decenal, which emits the typical metallic scent that humans associate with blood.

Once the researchers had identified a scent candidate that the predators should be attracted to, they wanted to test whether the predators were actually attracted to it in reality. So they designed a study to be conducted at Kolmården Wildlife Park, involving four predator species. How would the four predators -- Asian wild dogs, African wild dogs, South American bush dogs and Siberian tigers -- react when they caught a whiff of the scent?

Half-metre long wooden logs were impregnated with four different liquids: lab-produced aldehyde, horse blood, fruit essence, and a near-odourless solvent. The animals were exposed to one scent per day in their regular enclosure, while a group of students carefully observed their behaviour.

The results were unequivocal. The logs containing aldehyde were just as attractive stimuli as those containing blood, while the two other logs aroused little interest. The commonest behaviours were sniffing, licking, biting, pawing and toying. The tiger was the most persistent, while the South American bush dogs lost interest more quickly than the other species.

The study is the first to show that a single component can be just as attractive as the complex odour.

"How this has developed through evolution is an interesting question. Perhaps there is a common denominator for all mammalian blood," says Prof Laska.

He has plans for several follow-ups of the study, including how prey animals such as mice react to blood odour.

For the wildlife park, the study provided results that can be used in its daily operations. Animals in captivity require stimulation, so as not to deteriorate or become fat. The odourised logs can be a popular addition to the animal's environment.

Source: Linköping University

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Cats and humans have shared the same households for at least 9,000 years, but we still know very little about how our feline friends became domesticated.

The scientists fitted GPS collars and motion sensors on 38 free-ranging lynx for the study. Credit: Image courtesy of Albert-Ludwigs-Universität Freiburg

An international research team recorded and analyzed the activity patterns of 38 wild cats over the course of months Whether a lynx hunts by day or by night and how active it is overall depend primarily on the behavior of the wild cat's most important prey and its individual traits -- lighting conditions, on the other hand, do not play a major role in its basic behavioral patterns. This is the key finding of a study published in the journal PLOS ONE by an international research team led by forest scientist Dr. Marco Heurich.

The scientists fitted GPS collars and motion sensors on 38 free-ranging lynx for the study. Since the study sites were located across a wide latitudinal range from Central Europe to northern Scandinavia, the length of days and nights varied greatly between them. The team recorded and analyzed the activity patterns of the wild cats on a total of more than 11,000 days. The results reveal that lynx in more southerly regions are most active at dawn and dusk and that they move more by night than by day. They take their longest break in the middle of the day, and this break is extended as daylight duration increases. However, the cats exhibit this basic behavioral pattern independently of lighting conditions: "Lynx keep to a 24-hour rhythm with an active and a resting phase even on the polar day and the polar night," reports Heurich.

What the study found to be more important for explaining the wild cats' activity patterns are their individual traits: Young lynx are more active than adult lynx, and male adults are more active than female adults. In addition, they move more in spring and summer than in fall and winter, and the farther north they live, the larger the territory they cover -- and this of course results in higher activity. Lynx adapt their hunting schedule to the behavior of their prey. In polar regions, the height of their activity at dusk is less pronounced. 

This corresponds to the behavioral pattern of reindeer, which exhibit a steady movement profile outside of their sleeping phases.. In Central Europe, by contrast, the team found a maximum amount of activity at dusk -- in lynx as well as in deer. "The findings of this study make an important contribution to our understanding of the habits of predatory animals in our landscape," says Heurich. "They also show that human activities in the areas included in the study do not have a general influence on the activity pattern of the animals."

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