30th Nov 2014, 06:55 PM #1611
Re: Health Bulletin
Late-night snacks may damage memory
Late-night meals may interfere with your memory, a new study has warned.
The study in mice found that eating during times of day when one would normally be sleeping impaired the animals' memory for objects they had seen, even when the rats got the same amount of sleep as mice on a normal eating and sleeping schedule.
Study co-author Christopher Colwell, of the University of California, Los Angeles, and a team of researchers acclimatised mice to a normal sleep schedule, sleeping during the day. Mice are nocturnal, so they are normally awake at night and asleep during the day.
Then, the researchers allowed some of the animals to eat only during the time they were typically asleep, while allowing others to eat when the animals would normally be awake, 'LiveScience' reported.
The mice on the misaligned eating schedule had shifted sleep times, but they still slept for the same total amount of time, ate the same amount of food and weighed the same as the mice that ate at normal times, Colwell said.
The researchers then tested the mice's memory. In one experiment, they put the mice in a box with two different objects, and allowed them to explore.
Then, after putting the animals on different feeding schedules, the researchers placed them in the box with one of the familiar objects and one new object, and measured how long the mice spent exploring each one.
Compared with the mice on the aligned eating schedule, the misaligned mice showed a significant decline in memory.
The animals on the altered feeding and sleep schedule spent more time exploring the familiar object, suggesting they didn't remember encountering the object before
In a second experiment, the researchers conditioned both groups of mice to feel fear in a certain location, and later put them back in that location to see if they showed fear.
The mice on the shifted eating schedule froze less often in the fearful situation than their normal-schedule peers, suggesting the odd eating and sleeping schedule affected the animals' memory of scary situations.
The researchers also found that the mice that ate during normal sleeping periods learned less quickly than the mice that ate at normal times.
The study was presented at the annual meeting of the Society for Neuroscience in Washington, DC.
2nd Dec 2014, 05:12 PM #1612
Re: Health Bulletin
HIV's ability to cause AIDS is weakening over time, study finds
Rapid evolution of HIV, the human immunodeficiency virus, is slowing its ability to cause AIDS, according to a study of more than 2,000 women in Africa.
Scientists said the research suggests a less virulent HIV could be one of several factors contributing to a turning of the deadly pandemic, eventually leading to the end of AIDS.
"Overall we are bringing down the ability of HIV to cause AIDS so quickly," Philip Goulder, a professor at Oxford University who led the study, said in a telephone interview.
"But it would be overstating it to say HIV has lost its potency — it's still a virus you wouldn't want to have."
Some 35 million people currently have HIV and AIDS has killed around 40 million people since it began spreading 30 years ago.
But campaigners noted on Monday that for the first time in the epidemic's history, the annual number of new HIV infections is lower than the number of HIV positive people being added to those receiving treatment, meaning a crucial tipping point has been reached in reducing deaths from AIDS.
Goulder's team conducted their study in Botswana and South Africa — two countries badly hit by AIDS — where they enrolled more than 2,000 women with HIV.
First they looked at whether the interaction between the body's natural immune response and HIV leads to the virus becoming less virulent or able to cause disease.
Previous research on HIV has shown that people with a gene known as HLA-B*57 can benefit from a protective effect against HIV and progress more slowly than usual to AIDS.
The scientists found that in Botswana, HIV has evolved to adapt to HLA-B*57 more than in South Africa, so patients no longer benefited from the protective effect. But they also found the cost of this adaptation for HIV is a reduced ability to replicate — making it less virulent.
The scientists then analysed the impact on HIV virulence of the wide use of AIDS drugs. Using a mathematical model, they found that treating the sickest HIV patients -- whose immune systems have been weakened by the infection — accelerates the evolution of variants of HIV with a weaker ability to replicate.
"HIV adaptation to the most effective immune responses we can make against it comes at a significant cost to its ability to replicate," Goulder said. "Anything we can do to increase the pressure on HIV in this way may allow scientists to reduce the destructive power of HIV over time."
The study was published on Monday in the journal Proceedings of the National Academy of Sciences (PNAS).
2nd Dec 2014, 05:14 PM #1613
Re: Health Bulletin
Don't miss vitamin A after weight-loss surgery
People who have undergone bariatric surgery to shed weight should not miss on taking the prescribed supplements including Vitamin A to protect their eyes, says a study.
"Taking in too little Vitamin A could in some cases cause night blindness, dry eyes, corneal ulcers and, in extreme cases, total blindness," said Rui Azevedo Guerreiro and Rui Ribeiro of Centro Hospitalar de Lisboa Central in Portugal.
For the study, the researchers reviewed what little research there currently is on the occurrence of eye conditions following bariatric surgery.
One of the drawbacks of these operations is that patients can develop nutrient deficiencies.
This happens, for example, when patients vomit more often, eat less or develop food intolerances.
"There is a risk that bariatric surgery patients, who do not take the vitamin and mineral supplements prescribed to them, could develop eye-related complications because of nutrient deficiencies," Azevedo Guerreiro said.
In general, Vitamin A deficiency and eye-related complications seem to be more prevalent after malabsorptive bariatric surgery, the study noted.
The review was published in Springer's journal Obesity Surgery.
2nd Dec 2014, 05:15 PM #1614
Re: Health Bulletin
Statins not linked with reduced fracture risk
Contrary to prevalent suggestions that statin users may have a reduced risk of fractures, researchers have found that treatment with an anti-cholesterol medicine did not reduce the risk of fracture among men and women.
"Our study does not support the use of statins in doses used for cardiovascular disease prevention to reduce the risk of fracture," the researchers said.
Jessica Pena from Albert Einstein College of Medicine, New York, and co-authors examined whether statin therapy reduced the risk of fracture in a trial that enrolled 17,802 men (older than 50 years) and women (older than 60 years).
Participants were divided equally in two groups: one group received 20 mg daily of the anticholesterol medicine rosuvastatin while the other received placebo.
There were 431 fractures reported during the study with 221 fractures among participants who took rosuvastatin compared with 210 fractures among individuals who received placebo, according to the study results.
Cardiovascular disease (CVD) and the bone weakening disease osteoporosis may share common biological pathways with inflammation key to the development of atherosclerosis, which is hardening of the arteries, and possibly the development of osteoporosis.
Several studies suggest statin users may have a reduced risk of fractures, while other studies find no association.
The new study appeared online in the journal JAMA Internal Medicine.
2nd Dec 2014, 05:16 PM #1615
Re: Health Bulletin
Manchester United keen on Atletico Madrid defender Diego Godin
Manchester United are keen to sign Atletico Madrid central defender Diego Godin. With the transfer window re-opening on January, Louis van Gaal looks tempted to recruit the Uruguayan who has been named in the FIFA's shortlist of Europe's best defenders for the 2013-14 season.
According to reports Van Gaal is said has not ruled out meeting the 28-year-old's £28m buy-out clause with the Spanish champions.
The Uruguayan has been one of Atletico's most consistent performers over the past two years, guiding the team to the La Liga title and the Champions League final in 2013-14. He was a key figure in the Atletico team that won Spanish Super Cup and the UEFA Super Cup.
In the current season, he has so far started every match in the league, which is proof of the defender's vitality.
Godin will add a lot of experience in the United defence and can lead the backline with ease. United, who have been badly hit with injuries especially to the defenders, need a consistent performer and Godin fits the bill perfectly. The likes of Phil Jones, Johnny Evans and Chris Smalling have often been sidelined over the years for various injuries and lack leadership qualities.
In the central defending position, United added former Sporting Lisbon's versatile defender Marcos Rojo in their ranks in the summer, after the departure of veterans Rio Ferdinand and Nemanja Vidic.
With the injury ridden back-line, United had to play the likes of academy graduates Tyler Blackett and Paddy Mcnair. They have been promising so far and the inclusion of a world class defender will help these youngsters learn further.
Earlier, United who were keen on Borussia Dortmund's Mats Hummels, signed a new deal with the German outfit. Reports suggest that presently the club are also looking at FC Basel's Fabian Schar, Real Madrid youngster Raphael Varane and Dynamo Kiev star Aleksandar Dragovic. Also Premier League experienced campaigners such as Aston Villa's Ron Vlaar and Stoke's Ryan Shawcross too have been linked with the English giants.
Manchester United who have had 41 different injuries this season, take on Stoke City in a crucial matchweek 14 encounter at home on Tuesday in the Premier League.
3rd Dec 2014, 03:04 PM #1616
Re: Health Bulletin
Doctors put chip in brain to make deaf children hear
Parents of two-year-old Guhan and five-year-old Beninal had only one dream - to hear them talk in their lifetime. The children, hailing from two poor families, were born deaf, and hence couldn't speak too. While Guhan's father was a farmer in Thanjavur district, Beninal's was a house painter in Aranthangi in Pudukottai. Both, struggling to make ends meet, couldn't afford the huge treatment costs.
The state government's health insurance scheme came to their rescue. A team of city doctors performed complex surgeries, which involved implanting the hearing device , on the children, who are now on the path to recovery. The surgeries that cost 18.25 lakh for each child were performed free of cost, making these the most expensive surgeries the government has ever paid for.
Guhan and Beninal were both deaf since birth. While 99% of children with deafness can be treated with a cochlear implant, these two fell in the 1% bracket as they were born without a cochlea. "So we had to perform a surgery and implant the hearing device directly in the brain, which makes this procedure complex ," said Dr Mohan Kameshwaran of Madras ENT Research Foundation, who performed the surgery.
Explaining the procedure, Dr M C Vasudevan, a neurosurgeon from Voluntary Health Services, said, "It involves opening the skull and planting the chip in the brainstem. It is a critical procedure as the brainstem has the nerves responsible for all the vital activities of the body." The chip bypasses the absent cochlea and directly stimulates the hearing nerves that are present in the brain. Once the wound heals, an external device is fitted three months after the surgery. The children would also be made to undergo rehabilitation to gain speech, the doctor said.
The procedure which took more than five hours was performed jointly by ENT and neurosurgery teams. "TN has the highest deafness rate with 6 in 1,000 children born with hearing loss. The main reason for this is consanguineous marriage." said Dr Kameshwaran.
3rd Dec 2014, 03:14 PM #1617
Re: Health Bulletin
For first time, scientists make synthetic enzymes
In a major breakthrough, scientists have for the first time made synthetic enzymes — the vital ingredients needed for life — from artificial genetic material that does not exist outside the laboratory.
The milestone could soon lead to new ways of developing drugs and medical treatments.
Medical Research Council (MRC) scientists said the enzymes were made from artificial genetic material. Their synthetic enzymes, which are made from molecules that do not occur anywhere in nature, are capable of triggering chemical reactions in the lab.
The research gives new insights into the origins of life and could provide a starting point for an entirely new generation of drugs and diagnostics.
The findings build on which saw them create synthetic molecules called 'XNAs' that can store and pass on genetic information, in a similar way to DNA.
Using their lab-made XNAs as building blocks, the team has now created 'XNAzymes', which power simple reactions, such as cutting up or stitching together small chunks of RNA, just like naturally occurring enzymes.
Dr Alex Taylor, the study's first author said, "The creation of synthetic DNA, and now enzymes, from building blocks that don't exist in nature also raises the possibility that, if there is life on other planets, it may have sprung up from an entirely different set of molecules, and it widens the possible number of planets that might be able to host life."
DNA and RNA are the building blocks of life, storing all of our genetic information and passing it on to future generations.
Illustration of the various stages of tyrosine metabolism, which, thanks to enzymes E1, E2, E3 and E4, enables the production of complex DOPA molecules, dopamine, noradrenaline and adrenaline in the chromaffin cells of the adrenal medulla and melanin in skin cells.
Scientists who led the research at the MRC Laboratory of Molecular Biology, said, "All life on earth depends on a series of chemical reactions, from digesting food to making DNA in our cells. Many of these reactions are too sluggish to happen at ambient temperatures and pressures, and require enzymes to kick-start or 'catalyse' the process."
Every one of our cells contains thousands of different enzymes, many of which are proteins. But some of the key fundamental reactions necessary for life are performed by RNA, a close chemical cousin of DNA. Life itself is thought to have begun with the evolution of a self-copying RNA enzyme.
Dr Taylor explains: "Until recently, it was thought that DNA and RNA were the only molecules that could store genetic information and, together with proteins, the only biomolecules able to form enzymes. Our work suggests that, in principle, there are a number of possible alternatives to nature's molecules that will support the catalytic processes required for life. Life's 'choice' of RNA and DNA may just be an accident of prehistoric chemistry."
In 2012, the group showed that six alternative molecules, called XNAs, could also store genetic information and evolve through natural selection. They have now expanded on this principle to discover, for the first time, four different types of synthetic catalyst formed from these entirely unnatural building blocks.
Methyltransferase complexed with DNA, molecular model. The strand of DNA (red and pink) is enclosed by DNA methyltransferase 1 (DNMT-1, blue). This enzyme acts to add methyl groups to the DNA, a process called DNA methylation, which can silence and regulate genes without changing the actual genetic sequence. DNA methylation is also being studied in relation to cancer.
The XNAzymes are capable of catalysing simple reactions like cutting and joining RNA strands in a test tube. One of the XNAzymes can even join XNA strands together, which represents one of the first steps to creating a living system.
Because their XNAzymes are much more stable than naturally occurring enzymes, the scientists believe they could be particularly useful in developing new therapies for a range of diseases, including cancers and viral infections, which exploit the body's natural processes to take hold in the body.
They added: "Our XNAs are chemically extremely robust and, because they do not occur in nature, they are not recognized by the body's natural degrading enzymes. This might make them an attractive candidate for long-lasting treatments that can disrupt disease-related RNAs."
3rd Dec 2014, 03:20 PM #1618
Re: Health Bulletin
Human eye can see 'invisible' infrared light
Any science textbook will tell you that humans cannot see infrared light, but researchers have found that under certain conditions our eyes can actually detect the 'invisible' light.
Like X-rays and radio waves, infrared light waves are outside the visual spectrum.
Using cells from the retinas of mice and people, and powerful lasers that emit pulses of infrared light, the researchers found that when laser light pulses rapidly, light-sensing cells in the retina sometimes get a double hit of infrared energy.
When that happens, the eye is able to detect light that falls outside the visible spectrum.
"We're using what we learned in these experiments to try to develop a new tool that would allow physicians to not only examine the eye but also to stimulate specific parts of the retina to determine whether it's functioning properly," said senior investigator Vladimir J Kefalov, associate professor of ophthalmology and visual sciences at Washington University.
The study was initiated after scientists reported seeing occasional flashes of green light while working with an infrared laser.
Unlike the laser pointers used in lecture halls or as toys, the powerful infrared laser the scientists worked with emits light waves thought to be invisible to the human eye.
"They were able to see the laser light, which was outside of the normal visible range, and we really wanted to figure out how they were able to sense light that was supposed to be invisible," said Frans Vinberg, one of the study's lead authors.
Researchers examined the scientific literature and revisited reports of people seeing infrared light.
They repeated previous experiments in which infrared light had been seen, and they analysed such light from several lasers to see what they could learn about how and why it sometimes is visible.
"We experimented with laser pulses of different durations that delivered the same total number of photons, and we found that the shorter the pulse, the more likely it was a person could see it," Vinberg said.
"Although the length of time between pulses was so short that it couldn't be noticed by the naked eye, the existence of those pulses was very important in allowing people to see this invisible light," Vinberg added.
The findings are published in the journal PNAS.
4th Dec 2014, 12:54 PM #1619
Re: Health Bulletin
Why some smokers get back to smoking after kicking the butt
A new study has examined that brain activity in humans predict chances of relapsing after people quit smoking.
The study conducted at Penn State University suggested that quitting smoking sets off a series of changes in the brain and it may better identify smokers who will start smoking again i.e. a prediction that goes above and beyond today's clinical or behavioral tools for assessing relapse risk.
James Loughead, PhD, associate professor of Psychiatry, and Caryn Lerman, PhD, a professor of Psychiatry and director of Penn's Center for Interdisciplinary Research on Nicotine Addiction, found that smokers who relapsed within seven days from their target quit date had specific disruptions in the brain's working memory system during abstinence that separated them from the group who successfully quit. Such neural activity was mainly a decrease in the part of the brain that supported self-control and a boost in the area that promotes an "introspective" state could help distinguish successful quitters from those who fail at an earlier stage and serve as a potentially therapeutic target for novel treatments.
Researchers used functional magnetic resonance imaging (fMRI) to explore the effects of brief abstinence from smoking on working memory and its associated neural activation in 80 smokers seeking treatment. Participants were between 18 and 65 and reported smoking more than 10 cigarettes a day for more than six months.
Researchers determined predictive values of these two relapse models, as well as a new model that includes the working memory data. Using resampling methods that generate 1,000 replicates of the data from the 80 smokers, they found that incorporating the working memory-related brain activity resulted in an 81 percent correct prediction rate, a significant improvement over current models and without that data, the prediction values were 73 percent for the model of withdrawal symptoms and demographic/smoking history predictors, and 67 percent for demographic/smoking history predictors only.
The study is published in the journal Neuropsychopharmacology.
4th Dec 2014, 01:39 PM #1620
Re: Health Bulletin
Scientists confirm eating late at night causes weight gain
Scientists have confirmed that eating late at night causes weight gain suggesting that restricting eating hours could help fight high cholesterol, diabetes and obesity.
Confining meals to a 12 hour window, such as 8am to 8pm, and fasting for the remaining day, appears to make a huge difference to whether fat is stored, or burned up by the body.
A new study by researchers at the Salk Institute cautions against an extended period of snacking, suggesting instead that confining caloric consumption to an 8 to 12 hour period — as people did just a century ago-might stave off high cholesterol, diabetes and obesity.
The results add to mounting evidence suggesting that it's not just what we eat but when we eat it that matters to our health. Although the intervention has not yet been tested in humans, it has already gained visibility as a potential weight loss method - and, in mice, it may reveal what causes obesity and related conditions in the first place.
In 2012, Satchidananda Panda, a Salk associate professor, showed that mice which were fed a high-fat diet, but allowed access to that diet for only eight hours per day, were healthier and slimmer than mice given access to the same food for the whole day, even though the two groups consumed the same number of calories.
The new study shows the benefits of time restriction is surprisingly more profound than initially thought and can reverse obesity and diabetes in animal models.
Panda says, "These days, with the abundance of artificial light, TV, tablets and smartphones, adults and children alike are burning the midnight oil. What they are not burning is calories: with later bedtimes comes the tendency to eat.''
The authors demonstrated that time restriction better synchronizes the function of hundreds of genes and gene products in our body with the predictable time of eating.
Panda and his researchers, who study the body's 24-hour rhythms, wanted to know how forgiving time-restricted feeding was.
In the new study, Panda's group subjected nearly 400 mice, ranging from normal to obese, to various types of diets and lengths of time restrictions. They found that the benefits of time-restricted feeding showed up regardless of the weight of the mouse, type of diet and length of the time restriction (to some degree).
Regardless of whether their diets were high in fat, fat and sucrose or just fructose, mice that were given time restrictions of 9 to 12 hours-and consumed the same amount of daily calories as their unrestricted counterparts-gained less weight than the controls, researchers found.
In particular, variations in the time window in which the mice were allowed to eat a high-fat diet-including 9-, 10- and 12-hour periods-all resulted in similarly lean mice. For a 15-hour group, the benefits conferred by time restriction became more modest.
Researchers gave some of the time-restricted mice a respite on weekends, allowing them free access to high-fat meals for these two days. These mice had less fat mass and gained less weight than the mice given a freely available, high-fat diet the whole time. In fact, the mice that were freely fed just on weekends looked much the same as mice given access to food 9 or 12 hours a day for seven days a week, suggesting that the diet can withstand some temporary interruptions.
"The fact that it worked no matter what the diet, and the fact that it worked over the weekend and weekdays, was a very nice surprise," says the study's first author Amandine Chaix, a postdoctoral researcher in Panda's lab. More importantly, for the mice that had already become obese by eating a freely available high-fat diet, researchers restricted their food access to a nine-hour window. Although the mice continued to consume the same number of calories, they dropped body weight by five percent within a few days. Importantly, eating this way prevented the mice from further weight gain (by about 25 percent by the end of the 38-week study) compared to the group kept on the freely available high-fat diet.
The group also compared mice given a more balanced diet, showing that the time-restricted mice had more lean muscle mass than their unfettered littermates.
It's an interesting observation that although the mice on a normal diet did not lose weight, they changed their body composition," Panda says. "That brings up the question—what happens? Are these mice maintaining their muscle mass which might have been lost with free feeding, or are they gaining muscle mass?"