Knowledge Update

New York, March 17 (IANS) In the early stages of Alzheimer's disease, patients are often unable to remember recent experiences. However, a significant research suggests that those memories are still stored in the brain and can be retrieved with a new technique in the near future.

According to neuroscientists including an Indian-origin scientist from the Massachusetts Institute of Technology (MIT), mice in the early stages of Alzheimer's can form new memories just as well as normal mice but cannot recall them a few days later.Furthermore, the researchers were able to artificially stimulate those memories using a technique known as optogenetics, suggesting that those memories can still be retrieved with a little help. Although optogenetics cannot currently be used in humans, the findings raise the possibility of developing future treatments that might reverse some of the memory loss seen in early stage Alzheimer's.

“The important point is that this is a proof of concept. That is, even if a memory seems to be gone, it is still there. It's a matter of how to retrieve it,” said Susumu Tonegawa, director of the RIKEN-MIT Center for Neural Circuit Genetics at the Picower Institute for Learning and Memory.Tonegawa is the senior author of the study which appeared in the journal Nature, and Dheeraj Roy, an MIT graduate student, is the paper's lead author.

The researchers have also shown that they can manipulate these memory traces or engrams to plant false memories, activate existing memories, or alter a memory's emotional associations.To investigate this further, the researchers studied two different strains of mice genetically engineered to develop Alzheimer's symptoms along with a group of healthy mice.All of these mice, when exposed to a chamber where they received a foot shock, showed fear when placed in the same chamber an hour later. However, when placed in the chamber again several days later, only the normal mice still showed fear. 

The Alzheimer's mice did not appear to remember the foot shock.

"Short-term memory seems to be normal, on the order of hours. But for long-term memory, these early Alzheimer's mice seem to be impaired," Roy said.

The researchers then showed that while the mice cannot recall their experiences when prompted by natural cues, those memories are still there.
“Directly activating the cells that we believe are holding the memory gets them to retrieve it," Roy noted, adding that “this suggests that it is indeed an access problem to the information, not that they're unable to learn or store this memory”.
“If we want to recall a memory, the memory-holding cells have to be reactivated by the correct cue. If the spine density does not go up during learning process, then later, if you give a natural recall cue, it may not be able to reach the nucleus of the engram cells," Tonegawa explained.
The researchers were also able to induce a longer-term reactivation of the "lost" memories by stimulating new connections between the entorhinal cortex region of the brain and the hippocampus.

“It's possible that in the future some technology will be developed to activate or inactivate cells deep inside the brain, like the hippocampus or entorhinal cortex, with more precision," Tonegawa added.​

​New York, March 11 (IANS) A team of US researchers has identified a new bacteria that may keep bad bacteria in check and can help prevent oral cavities using probiotics.

According to researchers, the findings could lead to the development of a supplement that patients could take orally to prevent cavities.

"A12" bacteria has a potent ability to battle a particularly harmful kind of streptococcal bacteria, which metabolises sugar into lactic acid, contributing to acidic conditions in the mouth that form cavities. 

The researchers found that A12 not only helps neutralise acid by metabolising arginine in the mouth, it also often kills Streptococcus mutans.

“To maintain a healthy mouth, the oral environment must have a relatively neutral chemical make-up, or a neutral pH. When the environment in the mouth becomes more acidic, dental cavities or other disorders can develop,” said Robert Burne from the University of Florida's college of dentistry.

"At that point, bacteria on the teeth make acid and acid dissolves the teeth. It's straightforward chemistry," Burne added in the paper published in the journal Applied and Environmental Microbiology.

For the study, researchers collected plaque samples, isolating more than 2,000 bacteria and then screened them to find bacteria that fit the bill.

Dental plaque is a mass of bacteria that grows on the surface of teeth and can contribute to the formation of cavities.

The results showed that out of these, "A12" stood out for having all of the properties in a bacteria strain that could prevent cavities in a probiotic application.

The researchers have sequenced the entire genome of A12 and plan to turn this discovery into a tool to screen for people who are at a higher risk for developing oral cavities.​

London, March 15 (IANS) Traditionally viewed as a predator of insects, a new study has revealed that spiders like to spice up their menu occasionally with a vegetarian meal.The study showed evidence of spiders from ten families feeding on a wide variety of different plant types such as trees, shrubs, weeds, grasses, ferns or orchids. Also, these spiders demonstrated a diverse taste when it comes to the type of plant food: Nectar, plant sap, honeydew, leaf tissue, pollen and seeds are all on the menu.
As plant-dwelling, highly mobile foragers with excellent capability to detect suitable plant food, these spiders seems to be predestined to include some plant food in their diets.
Spiders diversifying their diet with plants are advantageous as it provides them with additional nutritional supplements and helps them survive when the insects are scarce, said the study detailed in the Journal of Arachnology.
"The ability of spiders to derive nutrients from plants is broadening the food base of these animals; this might be a survival mechanism helping spiders to stay alive during periods when insects are scarce," said study lead author Martin Nyffeler from University of Basel in Switzerland. However, the extent to which the different categories of plant food contribute to the spiders' diet is still largely unexplored.Although spiders feeding on plants are global in its extent, it is reported more frequently from warmer areas, the study said.The researchers suggested that it might be due to the fact that a larger number of the reports relate to nectar consumption, which has its core distribution in warmer areas where plants secreting large amounts of nectar are widespread.​

London, March 14 (IANS) Yoga may improve quality of life in patients suffering from abnormal heart rhythm because it gives them a method to gain some self control over their symptoms instead of feeling helples, says a new study.

The researchers examined the effects of yoga on patients with paroxysmal atrial fibrillation (AF) in which faulty electrical signals and rapid heart rate begin suddenly and then stop on their own.

"Many patients with paroxysmal atrial fibrillation (AF) can't live their lives as they want to -- they refuse dinners with friends, concerts and travelling - because they are afraid of an AF episode occurring," said one of the researchers Maria Wahlstrom from Sophiahemmet University in Sweden.

"AF episodes are accompanied by chest pain, dyspnoea and dizziness," added Wahlstrom in the study published in the European journal of cardiovascular nursing.

These symptoms are unpleasant and patients feel anxious, worried and stressed that an AF episode would occur. 

AF is the most common cardiac rhythm disorder and has no cure, the researches pointed out.

Patients with paroxysmal AF experience episodes of AF usually lasting less than 48 hours and stop by themselves, although in some patients they can last up to seven days. 

The team included 80 patients with paroxysmal AF who were randomised to yoga or a control group that did not do yoga. 

Yoga was performed for one hour, once a week, for 12 weeks in the hospital with an experienced instructor, which included light movements, deep breathing and meditation.

After 12 weeks, the yoga group had higher "SF-36" mental health scores, lower heart rate and lower systolic and diastolic blood pressure than the control group.

"We found that patients who did yoga had a better quality of life, lower heart rate and lower blood pressure than patients who did not do yoga. The breathing and movement may have beneficial effects on blood pressure," Wahlstrom stated.

"Patients in the yoga group said it felt good to let go of their thoughts and just be inside themselves for awhile," Wahlstrom noted.

​London, March 11 (IANS) It is often assumed that as our income rises so does our life satisfaction but this may not be the case with many people.

According to researchers, what really matters is when income is lost and this is only important for people who are highly conscientious, hard working and diligent.

The research, which examined levels of life satisfaction and income changes in more than 18,000 adults over a nine-year period, revealed that income change is only important when individuals with specific personality characteristics experience an income loss.

According to the team, continually increasing our income is not an important factor for achieving greater happiness and well-being for most people living in economically-developed countries.

"Instead, we should aim for financial stability to achieve greater happiness while protecting those individuals who experience negative income shocks," said Christopher Boyce of the behavioural science centre at the University of Stirling in Britain.

The study, involving two separate samples from Germany and Britain, asked participants annually about their income level and how satisfied they were with life.

Participants also answered questions on their personality at the start of the study.

Results revealed that regardless of personality, income increases did not affect life satisfaction.

When people lost income, however, there was a reduction in their life satisfaction.

This was far greater for those who reported themselves as being conscientious, namely they were thorough in their attitudes to life and work, energetic, effective and efficient in how they did things.

The study accounted for shifting circumstances such as entering or leaving work and changes to health and household make up.

It found that for people that were only even moderately conscientious, a loss of income had a negative impact at least two and a half times greater than less conscientious individuals.​

Raymon Tomlinson, the inventor of modern email and a technological leader, has died.

​London, March 4 (IANS) Overturning an earlier order from the Hamburg data protection authority on Facebook's "real name" policy, a German court has allowed the social networking giant to prevent its users from using fake names.

​New York, March 4 (IANS) Five or more servings of yoghurt a week are likely to help women in reducing the risk of having high blood pressure, finds a study.

Women who ate five or more servings of yoghurt per week, compared to those consuming one serving per month, had a 20 percent reduction in the risk of having high blood pressure, the results of the study showed.Adding yoghurt to an otherwise healthy diet seems to reduce the long-term risk of high blood pressure in women.
"Our study shows that daily intake of dairy products, particularly yoghurt, lowers the risk of developing high blood pressure, which is a key risk factor for the development of heart diseases and strokes," said lead author Justin Buendia, doctoral student at Boston University in US.
Moreover, several servings of milk and cheese each day can also have beneficial effects on blood pressure "although the effects of yoghurt seemed stronger than other forms of dairy", Buendia noted.
To examine the long-term effects of yoghurt on high blood pressure in middle-aged adults, researchers analysed data of participants in two Nurses' Health Study cohorts (NHS and NHS II),on women between 25-55 years of age, and the Health Professionals Follow-up Study on men between 40-75 years of age.
The authors also evaluated whether the effects of consuming larger amounts of yoghurt were different among subjects with a healthy overall diet. 

To do this, subjects were given a score to reflect how closely their diet matched that of a DASH (Dietary Approaches to Stop Hypertension) diet, intake of fruits, vegetables, nuts and beans to lower blood pressure.The benefit of five or more servings of yoghurt on the risk of high blood pressure was stronger than the DASH diet. 
In the pooled analysis, men and women who had a higher DASH score and who consumed yoghurt five or more times per week had a 31 percent lower risk of developing high blood pressure compared with those who had the lowest yoghurt intakes (one time per week) and the lowest DASH scores, the researchers claimed.The study was presented at the ongoing American Heart Association's Epidemiology/Lifestyle 2016 Scientific Sessions in Arizona.​

​New York, March 3 (IANS) A 10 percent drop in price for healthy foods and a 10 percent increase in the price of unhealthy foods could potentially prevent a significant number of people from dying from heart disease and stroke, suggests a new study.
Using a computer-based model, the researchers from Harvard University in US revealed how price changes might impact eating habits over time and whether this could reduce heart diseases. The study revealed that a 10 percent price reduction on fruits and vegetables could overall decrease 1.2 percent deaths from cardiovascular diseases in five years and almost 2 percent within 20 years. 
Heart attacks and strokes can decrease by 2.6 percent and 4 percent, respectively, over a period of 20 years.Also, a 10 percent price reduction on grains can result in 0.2 percent decrease from heart diseases within five years and 0.3 percent by 20 years. Further, a price increase of 10 percent on sugary drinks, deaths from heart diseases overall could decrease by nearly 0.1 percent within 5 years and 0.12 percent within 20 years. Specifically, heart attacks could decrease by 0.25 percent in both timeframes and strokes could decrease by 0.17 percent in 20 years. 
Diabetes could decrease by 0.2 percent in five years and 0.7 percent in 20 years.Combined, the model shows that by 2035 it would be possible to prevent 515,000 deaths from heart disease and nearly 675,000 events, such as heart attacks and strokes, across the nation with these small changes in price. 
If a change by one serving occurred daily, for example one more piece of fruit (100gm), one full serving of a vegetable (100 gm), one serving of whole grains (50 gm), and one less 8 oz sugar sweetened beverage were consumed then up to 3.5 million deaths and 4 million heart disease events could be averted over a 2 year period. 
"A change in your diet can be challenging, but if achieved through personal choice or changes in the market place, it can have a profound effect on your cardiovascular health," said lead author Thomas A. Gaziano, assistant professor at Harvard University.State and community leaders who want to improve the health of their communities can use these data to make impactful change, the researchers explained adding that the findings support the need to combine modest taxes and subsidies to better represent the real costs of food to health and society.
The research was presented at the American Heart Association's Epidemiology/Lifestyle 2016 Scientific 2016 meeting.​