Knowledge Update

​Toronto, Nov 17 (IANS) A single bout of sleep apnea - a condition where breathing repeatedly stops and starts during sleep -- impacts your ability to regulate blood pressure, says a study.

Sleep apnea can result in frequent periods of decreased oxygen levels in the body, known as intermittent hypoxia.

Just six hours of the fluctuating oxygen levels associated with sleep apnea can begin to deteriorate a person's circulatory system, the study found.

"While it is well established that sleep apnea is linked to high blood pressure, our study shows this condition has an impact on the cardiovascular system that can begin within a single day," said researcher Glen Foster, Assistant Professor at University of British Columbia's Okanagan campus in Canada.

"After just six hours of fluctuating oxygen levels, similar to what happens with sleep apnea, the body's ability to regulate blood pressure is impaired," Foster noted.

"These changes occurred almost immediately in healthy young adults who were not experiencing the cumulative effects years of sleep apnea could bring about," Foster said.

As part of his study, Foster examined the impact of intermittent hypoxia on the cardiovascular system in a few healthy young adults. 

Study participants wore a ventilating mask for six hours and oxygen levels were altered to mimic sleep apnea symptoms.

The study, published in the American Journal of Physiology, found that sleep apnea compromised the function of a person's baroreceptors--biological sensors that regulate blood pressure. 

It also found damaging blood flow patterns in the legs, which over time could impact vascular health.

"These findings suggest that interventions for people suffering sleep apnea should occur as soon as the condition is diagnosed," Foster said.

​New York, Nov 17 (IANS) High doses of vitamin D are likely to reduce the incidence of acute respiratory illness in older adults, suggests a study led by an Indian-origin researcher.

The study found that among those who took higher doses of vitamin D, there was a 40 per cent reduction in acute respiratory illness -- one of the leading causes of serious illness, debilitation and death among patients in nursing homes and other long-term care facilities.

"Vitamin D can improve the immune system's ability to fight infections because it bolsters the first line of defense of the immune system," said lead author Adit Ginde, professor at the University of Colorado, Denver, US.

"This is a potentially life-saving discovery. There is very little in a doctor's arsenal to battle ARI, especially since most are viral infections where antibiotics don't work. But vitamin D seems able to potentially prevent these infections," Ginde added.

In older people that first line of defence is often impaired. But vitamin D can reinforce it and prevent illnesses like pneumonia, influenza and bronchitis, Ginde said.

It may also prevent infections and exacerbations of chronic obstructive pulmonary disease (COPD) like emphysema.

Conversely, Ginde found that those who received higher doses of vitamin D also saw an increase in falls. 

The falls were lower in those given smaller doses rather than higher monthly doses of vitamin D.

For the study, the team looked at 107 patients with an average age of 84 over a 12 month period. 

Those who received higher doses saw acute respiratory illness cut nearly in half, but also had over double the incidence of falls, the study said.

The study was published in the Journal of the American Geriatrics Society.

​Washington, Nov 17 (IANS) Scientists have discovered a "great valley" in the southern hemisphere of Mercury, providing more evidence that the small planet closest to the sun is shrinking.

Scientists used images from NASA's MESSENGER spacecraft to create a high-resolution topographic map that revealed the broad valley -- more than 1,000 kilometres long -- extending into the Rembrandt basin, one of the largest and youngest impact basins on Mercury. 

"Unlike Earth's Great Rift Valley, Mercury's great valley is not caused by the pulling apart of lithospheric plates due to plate tectonics; it is the result of the global contraction of a shrinking one-plate planet," said lead author of the study Tom Watters, senior scientist at the Smithsonian National Air and Space Museum in Washington, D.C. 

About 400 kilometres wide and three kilometres deep, Mercury's great valley is smaller than Mars' Valles Marineris, but larger than North America's Grand Canyon and wider and deeper than the Great Rift Valley in East Africa, said the study published in the journal Geophysical Research Letters.

Mercury's great valley is bound by two large fault scarps ? cliff-like landforms that resemble stair steps. 

The scarps formed as Mercury's interior cooled and the planet's shrinking was accommodated by the crustal rocks being pushed together, thrusting them upward along fault lines, the study said.

NASA's MErcury Surface, Space ENvironment, Geochemistry and Ranging (MESSENGER) mission was launched on August 3, 2004 to understand Mercury, the smallest, densest and least-explored of the terrestrial planets.

​Toronto, Nov 16 (IANS) Exercise may help improve gait, balance and reduce risks of falls in individuals living with Parkinson's disease, researchers say.

Parkinson's Disease -- a neurodegenerative disease that impacts movement, often including tremors -- affects nearly seven to 10 million persons around the world, according to the Parkinson's Disease Foundation. 

Despite the progressive nature of the disease, people living with Parkinson's disease can expect to improve their physical condition by being more physically active, the researchers said.

"Exercise should be a life-long commitment to avoid physical and cognitive decline, and our research shows that this is also true for individuals with Parkinson's disease," said Christian Duval, Professor at the Universite du Quebec a Montreal in Canada. 

The study found that exercise in Parkinson's disease patients majorly benefitted physical capacities -- strength, flexibility --, physical and cognitive functional capacities -- gait, mobility, cognitive functions.

The physical activity was also effective for limb strength, endurance, flexibility or range of motion, motor control, and metabolic function in patients with Parkinson's disease. 

Exercise showed nearly 67 per cent improvement in upper limb strength, the researchers explained. 

However, physical activity seems less efficient at improving clinical symptoms of Parkinson's disease -- rigidity, tremor, posture alterations -- and psychosocial aspects of life -- quality of life and health management --, with only 50 per cent or less of results reporting positive effects. 

The impact of physical activity on cognitive functions and depression also appeared weaker, the researchers reported the in the paper published in the Journal of Parkinson's Disease. 

​New York, Nov 16 (IANS) Adverse childhood experiences such as abuse or neglect, dysfunctional homes or low socio-economic status may be associated with a risk of poor blood pressure regulation, a study has found.

The study showed that children who experienced such adverse environments in early life were far more likely to have higher blood pressure at night as well as blood pressure variability over 24 hours.

In addition they are also prone to rapid onset of hypertension -- risk factor for cardiovascular disease -- at an earlier age.

"Adverse environments in early life have been consistently associated with the increased risk of hypertension in later life," said lead author Shaoyong Su, Associate Professor at the Augusta University in Georgia, US. 

Blood pressure variability has been linked to a number of problems in adults, including decreased brain function in older adults, as well as increased risk of stroke and poorer post-stroke recovery. Likewise, early-onset hypertension and prehypertension have been linked to adverse preclinical cardiovascular disease, including left ventricular hypertrophy and evidence of increased arterial stiffness.

For the study, the team conducted periodic around-the-clock blood pressure monitoring to capture day and nighttime pressure readings in 373 participants between the ages of seven and 38 during a 23-year period. 

Those who reported childhood adversity were 17 per cent more likely to have blood pressure higher than the clinical definition of hypertension during the daytime.

Most physicians focus on average blood pressure readings, but the new findings suggest that they should also ask younger patients about childhood adversity and watch for high blood pressure variability, Su noted.

The research was presented at the American Heart Association's Scientific Sessions 2016 in Louisana, US.

​Washington, Nov 16 (IANS) To help learn more about the primitive building blocks of the solar system and answer questions about Earths neighbours like the moon and Mars, three federal entities in the US, including NASA, are reaffirming their commitment to search for Antarctic meteorites.

NASA, the National Science Foundation (NSF) and the Smithsonian Institution (SI) recently renewed their agreement to search for, collect and curate Antarctic meteorites in a partnership known as ANSMET -- the Antarctic Search for Meteorites Program, the US space agency said in a statement on Tuesday.

The signing of this new joint agreement advances the programme for an additional decade, replacing an earlier agreement signed in 1980.

"Antarctic meteorites are posing new questions about the formation and early history of our solar system. Some of these questions are spurring new exploration of the solar system by NASA missions," Smithsonian meteorite scientist Tim McCoy said.

Since the US began searching for meteorites in Antarctica in 1976, the ANSMET programme has collected more than 23,000 specimens, dramatically increasing the number of samples available for study from Earth's moon, Mars and asteroids. 

Among them are the first meteorites discovered to come from the moon and Mars, and the well-known ALH 84001 Martian meteorite, which helped renew interest in Mars exploration in the 1990s.

Meteorites are natural objects that fall to Earth from space and survive intact so they can be collected on the ground, or -- in this case -- on ice. 

Antarctica provides a unique environment for the collection of meteorites, because the cold desert climate preserves meteorites for long periods of time, NASA said. 

​New York, Nov 15 (IANS) Insomnia may raise your risks of an irregular and often rapid heartbeat, known as atrial fibrillation or arrhythmia, that can further increase your risk of stroke, heart failure and other heart-related complications, researchers have found.

Insomnia is having trouble falling asleep, not getting enough sleep, or having poor sleep.

Poor sleep is also known to increase the risk for high blood pressure, obesity and stroke -- key heart disease risk factors, said researchers from the University of Michigan in Ann Arbor, US.

The results showed that people diagnosed with insomnia had a 29 per cent higher risk of developing atrial fibrillation compared to those without insomnia.

People who reported frequent night-time awakening -- which puts extra stress on the heart's chambers -- had about a 26 per cent higher risk of developing atrial fibrillation compared to those who did not wake up a lot.

Having less rapid-eye movement (REM) sleep than other sleep phases during the night is also linked to higher chances of developing atrial fibrillation.

"By examining the actual characteristics of sleep, such as how much REM sleep you get, it points us toward a more plausible mechanism. There could be something particular about how sleep impacts the autonomic nervous system," said lead study author Matt Christensen, a medical student at the University of Michigan.

The autonomic nervous system plays a major role in controlling heart rate and blood pressure, Christensen added.

Getting enough physical activity, avoiding too much caffeine can enhance sleep quality and may also help prevent arrhythmia, the researchers suggested.

The preliminary research was presented at the American Heart Association's Scientific Sessions 2016 in Louisiana, recently.

New York, Nov 15 (IANS) Experience rather than possession is more likely to give individuals a greater sense of gratitude, and will also make them more generous towards others, a study involving an Indian-origin researcher has found.

Our deeds mean more to us. "We feel more gratitude for what we've done than for what we have," said Thomas Gilovich, Professor of psychology at the Cornell University.

"Think about how you feel when you come home from buying something new," Gilovich said in the study published in the journal, Emotion.

"You might say: this new couch is cool, however, you're less likely to say: I'm so grateful for that set of shelves. 

"But when you come home from a vacation, you are likely to say: I feel so blessed I got to go," he said. 

"People say positive things about the stuff they buy, but they don't usually express gratitude for it, or they don't express it as often as they do for their experiences," Gilovich added.

The researchers looked at 1,200 customer reviews, half for experiential purchases like restaurant meals and hotel stays and half for material purchases like furniture and clothing. 

Reviewers were more likely to spontaneously mention feeling grateful for experiential purchases than material ones, the study suggested.

"One of the reason for this increased gratitude may be because experiences trigger fewer social comparisons than material possessions. 

"Consequently, experiences are more likely to foster a greater appreciation of one's own circumstances," said Jesse Walker, Researcher at the Cornell University.

The researchers also looked at how gratitude for experiences versus material purchases affected pro-social behaviour. 

In a study involving an economic game, they found that thinking about a meaningful experiential purchase caused participants to behave more generously toward others than when they thought about a material purchase.

"This link between gratitude and altruistic behaviour is intriguing," said Amit Kumar, Researcher at the University of Chicago.

"It suggests that the benefits of experiential consumption apply not only to the consumers of those purchases themselves, but to others in their orbit as well," Kumar said.

Feeling gratitude increased happiness and social cohesion, better health outcomes, and even improved sleep quality, the study revealed.

New York, Nov 12 (IANS) Traumatic stress may have different impact in the brains of adolescent boys and girls, according to a new brain-scanning study.

The study found structural differences between the sexes in one part of the insula -- a brain region -- among the youth with post-traumatic stress disorder (PTSD) -- a mental health condition triggered by experiencing or seeing a terrifying event.

"The insula appears to play a key role in the development of PTSD. The difference we saw between the brains of boys and girls who have experienced psychological trauma is important because it may help explain differences in trauma symptoms between sexes," said Victor Carrion, Professor at Stanford University in California. 

"Our findings suggest it is possible that boys and girls could exhibit different trauma symptoms and that they might benefit from different approaches to treatment," added Megan Klabunde, psychologist from Stanford University.

In the study, the research team conducted MRI scans of the brains of 59 study participants aged 9-17. Thirty of them -- 14 girls and 16 boys -- had trauma symptoms, and 29 others -- the control group of 15 girls and 14 boys -- did not. 

In the control group, no differences was found in the brain structure of boys and girls. 

However, among the traumatised boys and girls, they saw differences in a portion of the insula called the anterior circular sulcus. This brain region had larger volume and surface area in traumatised boys than in boys in the control group. 

Insula's volume and surface area were smaller in girls with trauma than among girls in the control group, the researchers said.

In addition, the research also implies that traumatic stress could contribute to accelerated cortical ageing of the insula in girls who develop PTSD, Klabunde noted, adding that the study may help scientists understand how experiencing trauma could play into differences between the sexes in regulating emotions. 

The paper was published online in the journal Depression and Anxiety