Knowledge Update

​London, Dec 15 (IANS) Researchers have in a breakthrough study found that brains of people genetically inclined towards Alzheimer's are likely to show abnormal immune reactions as early as about seven years before the expected onset of dementia.

These immune responses can be detected by means of a protein known as "TREM2" and found in the cerebrospinal fluid, offering physicians the possibility to trace the progression of the disease, the study said. 

Thus, when the researchers measured the levels of TREM2 -- segregated by certain immune cells of the brain called microglia -- they were able to detect an increasing immune activity of the brain. 

"The activity of the microglia is stimulated by the dying brain cells, not by the deposits of amyloid proteins, called plaques, which also occur in Alzheimer's disease," said Christian Haass, Professor at Ludwig Maximilian University (LMU) in Munich, Germany.

The rise of TREM2 levels years before the expected occurrence of dementia symptoms can be monitored and thus the timing for the onset of dementia can be precisely predicted, the researchers noted.

"TREM2 levels could therefore be a biomarker used to track immune activity while Alzheimer's is progressing, irrespective of whether the disease is genetic or not. TREM2 may also serve as a therapeutic marker to monitor drug response," explained Michael Ewers, Professor at Ludwig Maximilian University (LMU). 

For the study, the team included 127 individuals, with an average age of 40 years, who had a genetic predisposition to Alzheimer's. The vast majority showed no symptoms of dementia or had only minor cognitive impairments. 

The study results are published in the journal Science Translational Medicine.

​London, Dec 15 (IANS) A cost-effective saliva test may have the potential to act as non-invasive marker of immunity and thus enable assessment of vaccination and protection against bacterial infections such as pneumococcal infections in the human body, a study has found.

Saliva test can be an attractive method of specimen collection particularly for children and the elderly, the researchers said.

"Saliva sampling is non-invasive, requires no specialist training or equipment, and may be more cost-effective," said lead author Jennifer Heaney from the University of Birmingham in Britain.

The study showed that IgG Pn antibodies in saliva correlated with antibody levels in serum in infants. 

Protection against bacterial infection is usually inferred by measuring antibody levels in blood serum.

But taking blood samples involves a number of logistical considerations and may not always be feasible, especially in developing countries or where children are involved. 


"The suggestion that antibody levels in saliva may be indicative of those in serum therefore has important implications for markers of immunity and vaccination in many parts of the world," Heaney added. 

Previous research showed that lower levels of antibodies in saliva are associated with of an elevated risk of mortality, and that saliva sampling to determine IgA secretion rate has the potential to be used as an indicator of overall health by professionals as part of a general check-up.

For the study, samples of both blood and saliva were taken from 72 healthy adults. Samples were then analysed to test for concentrations of IgG, IgM and IgA antibodies against 12 pneumococcal (Pn) antigens.

The results showed that in general, higher antibody concentrations in serum were associated with higher concentrations in saliva, with the strongest relationships observed for IgA antibodies.

The study was published in the journal Biomarkers.

​New York, Dec 14 (IANS) NASA's Curiosity rover has detected boron for the first time on the surface of Mars, indicating the potential for long-term habitable groundwater in the ancient past.

"No prior mission to Mars has found boron," said Patrick Gasda of the US Department of Energy's Los Alamos National Laboratory in New Mexico. 

"If the boron that we found in calcium sulfate mineral veins on Mars is similar to what we see on Earth, it would indicate that the groundwater of ancient Mars that formed these veins would have been 0-60 degrees Celsius and neutral-to-alkaline pH," Gasda noted.

The temperature, pH, and dissolved mineral content of the groundwater could make it habitable, according to the scientists.

The boron was identified by the rover's laser-shooting Chemistry and Camera (ChemCam) instrument, which was developed at Los Alamos National Laboratory in conjunction with the French space agency. 

Boron is famously associated with arid sites where much water has evaporated away. However, environmental implications of the boron found by Curiosity are still open to debate.

Whether Martian life has ever existed is still unknown. No compelling evidence for it has been found. When Curiosity landed in Mars' Gale Crater in 2012 the mission's main goal was to determine whether the area ever offered an environment favourable for microbes.

Curiosity is currently climbing a layered Martian mountain and finding rock-composition evidence of how ancient lakes and wet underground environments changed, billions of years ago.

The discovery of boron is only one of several recent findings related to the composition of Martian rocks. 

Hematite and clay minerals are among the other ingredients found to be more abundant in layers farther uphill, compared with lower, older layers examined earlier in the mission.

"The boron and clay underline the mobility of elements and electrons, and that is good for life," John Grotzinger of the California Institute of Technology, Pasadena, California, pointed out.

The findings were discussed in San Francisco during the American Geophysical Union conference.

​London, Dec 14 (IANS) A sound sleep in the first 24 hours after suffering a trauma can help individuals with post traumatic stress disorder (PTSD) to process the horrific experiences, a study has found.

People with PTSD experience highly emotional and distressing memories or even flashbacks where they feel as if they were experiencing the trauma all over again. 

Sleep could play a key role in processing what they have suffered.

"Our approach offers an important non-invasive alternative to the current attempts to erase traumatic memories or treat them with medication," said lead author Birgit Kleim from the University of Zurich. 

The findings showed that a good sleep can help weaken emotions connected to an existing memory, such as fear caused by traumatic experiences. 

In addition, sleep also helps contextualise the recollections, processing them as information and storing the memories. 

However, the process may take several nights, the researchers said.

"The use of sleep might prove to be a suitable and natural early prevention strategy," Kleim added.

For the study, the researchers showed participants a traumatic video. The recurring memories of the images in the film that haunted the participants for a few days were recorded in detail in a diary. 

Study participants were randomly assigned to two groups. One slept in the lab for a night after the video while their sleep was recorded via an electroencephalograph (EEG), the other group remained awake. 

The results revealed that people who slept after the film had fewer and less distressing recurring emotional memories than those who were awake.

"This supports the assumption that sleep may have a protective effect in the aftermath of traumatic experiences," Kleim said, in the study published in the journal Sleep.

​London, Dec 14 (IANS) A drug used for sleep disorder could also reduce the impulse for food, thereby helping food addicts to lose weight, a study says.

The researchers discovered that a drug called Modafinil, usually used for narcolepsy, shift work disorder and excessive daytime sleepiness, can reduce impulsivity and thus food addiction.

"We found Modafinil, which is already on the market, did reduce people's impulsive behaviour," said Ivo Vlaev, Professor at University of Warwick in Britain.

Impulsive behaviour is an important factor that could lead to to food addiction.

"It has been shown to reduce impulsiveness in a variety of disorders such as alcohol dependence, schizophrenia and ADHD (Attention-deficit/hyperactivity disorder). Food addicts suffer from the same neurobiological conditions so we believe it will help food addicts as well and our initial tests have backed up that theory," Vlaev noted.

This could have important implications for people who are obese. 

"There is mounting evidence to show that there is a substantial number of obese people who are food addicts because they have an inability to control their impulsive actions and this drug has shown it can give them more control, which will help overweight people lose weight and so improve their health," Vlaev said.

Food addicts have also been found to have a deficiency in a certain type of dopamine so that their sense of reward and pleasure is diminished, thus they have to eat more to reach the same level of pleasure as anybody else.

The drug, which is sold under a wide variety of brand names around the world, was one of two drugs tested by researchers, the other being Atomoxetine. 

Both drugs have been used for impulsive conditions, including ADHD.

In a paper published in the journal Personality and Individual Differences, the scientists conducted a series of trials on 60 men aged between 19 and 32, with 20 taking a placebo, 20 Atomoxetine and 20 Modafinil.

The tests revealed that those who had taken Modafinil had a significantly reduced level of impulsiveness, whereas Atomoxetine produced no difference compared to the placebo group.

"Modafinil was found to have an effect on impulsivity in healthy individuals and so would be able to have an even bigger effect on food addicts, who are lacking in certain types of dopamine," Vlaev said.

​New York, Dec 13 (IANS) An intense flare detected last year in a distant galaxy about four billion light years from Earth, considered to be the brightest supernova ever observed, is actually a tidal disruption event (TDE) -- the destruction of a star by a rapidly spinning supermassive black hole, suggests new research.

The findings are based on new astronomical observation data from the Las Cumbres Observatory (LCO), a global robotic telescope network, and the Hubble Space Telescope.

"We observed the source for 10 months following the event and have concluded that the explanation is unlikely to lie with an extraordinarily bright supernova," said lead researcher Giorgos Leloudas from Weizmann Institute of Science in Israel.

"Our results indicate that the event was probably caused by a rapidly spinning supermassive black hole as it destroyed a low-mass star," Leloudas explained.

Using images from the Hubble Space Telescope that were not available when the event, called ASASSN-15lh, was observed, the scientists found that the event occurred at the centre of the galaxy where the supermassive black hole resides. 

The black hole inferred to lie in this galaxy is more than 100 million times the mass of the sun.

For a star to be tidally disrupted by such a massive black hole -- rather than swallowed whole -- the black hole must be spinning very rapidly, said the study published in the journal Nature Astronomy.

This discovery marks the first time that a TDE has been used to probe the spin of a black hole, a property that is very difficult to measure and is used to infer the existence of so-called Kerr black holes.

ASASSN-15lh occurred when the star strayed too close to the supermassive black hole and was torn apart by the tides generated by the extreme gravity. 

The stellar material orbited around the black hole, collided with itself at high velocity and started falling into the black hole. 

This released copious amounts of energy and generated the bright flare astronomers observed as ASASSN-15lh.

"Years ago we just wouldn't have been able to follow an event like this," study co-author Andy Howell, University of California, Santa Barbara, US, noted.

"This study shows that large area surveys, a global robotic telescope network and a NASA satellite can come together to reveal dramatic new discoveries that wouldn't be possible without each piece of that puzzle," Howell said.

​New York, Dec 13 (IANS) Researchers have identified that bone marrow-derived cells are the source of suPAR -- a protein recently identified as both a reliable marker for chronic kidney disease and a pathogen of the often deadly condition.

The place of origin of suPAR in the human body had been a mystery until now. 

"SuPAR is not just a biomarker; it may also be a cause of the disease," said Jochen Reiser, Professor at Rush University in Illinois, US.

Thus the new discovery may aid search for kidney disease treatment and prevent recurrence after transplant, the researchers said. 

The research showed a type of immature myeloid cell, located in the bone marrow, as the source of abnormal levels of suPAR.

"These immature myeloid cells appear as a main source of circulating suPAR," Reiser added.

Myeloid cells are one of three main types of blood cells. It appears that "these cells are producing high amounts of suPAR, which becomes the mediator that communicates between the immune system and the kidney. At high levels, suPAR travels to the kidneys, causes a reaction, and takes the kidney down," Reiser explained.

The researchers identified bone marrow GR-1lo, Sca1+ immature myeloid cells as the specific type of cells giving rise to suPAR.

"The benefit of knowing what we know about suPAR is that it will allow for much better risk stratification," Reiser said. 

While smoking cessation and losing weight can help bring suPAR levels down. SuPAR levels will likely require pharmacological intervention because "suPAR still won't go down to completely normal levels just because of a better lifestyle," Reiser says.

As for treatments, "stem cell transplantation may prove to be a viable approach to treat diseases such as suPAR-associated kidney disease," the study, published in the journal Nature Medicine, stated.

​London, Dec 13 (IANS) Music may influence a man's ability to focus. While classical music can boost the concentration, rock music can distract, a new research has found.

Interestingly, women's ability to focus is not much affected by the background music -- be it Mozart or AC/DC, the study showed.

"One of our areas of research is how we can boost performance in many different settings -- from rowing in the Olympics, to a musical performance or delivering an important speech," said lead author Daisy Fancourt from the Centre for Performance Science, a collaboration between Imperial College London and the Royal College of Music in Britain.

"This study suggests that for men who are operating or playing a board game, rock music may be a bad idea," Fancourt noted.

In the study, the research team asked 352 participants to play the game Operation.

This game involves removing various body parts from a pretend patient -- Cavity Sam -- whose nose flashes and buzzes if your tweezers touch the metal sides of the body.

Researchers gave the volunteers headphones that played one of three tracks -- Andante from Sonata for Two Pianos by Mozart, Thunderstruck by AC/DC, or the sound of an operating theatre.

The team then timed them how long it took the participants to remove three body parts, as well as tracking their mistakes.

The results revealed that men who listened to AC/DC were slower and made more mistakes, compared to men who listened to Mozart or the sound of an operating theatre.

Thunderstruck triggered around 36 mistakes on average, while the Sonata and operating theatre noises caused 28.

It took volunteers around one minute to complete the task.

Women, however, did not seem to be distracted by the rock music, and none of the three tracks made any difference to performance or speed, showed the findings published in the Medical Journal of Australia.

Generally, women took longer to remove the body parts, but made fewer mistakes.

The researchers are unsure why rock music affected men more than women. 

One explanation, they said, could be that rock music causes more auditory stress -- a state triggered by loud or discordant music -- in men.

The scientists also asked people about their musical tastes, and found that Mozart only reduced the number of mistakes people made if they reported high levels of appreciation for the Sonata they listened to.

New York, Dec 13 (IANS) Researchers have found that intermittent fasting inhibits the development and progression of the most common type of childhood leukemia.

This strategy was not effective, however, in another type of blood cancer that commonly strikes adults.

"This study using mouse models indicates that the effects of fasting on blood cancers are type-dependent and provides a platform for identifying new targets for leukemia treatments," said senior author of the study Chengcheng (Alec) Zhang, Associate Professor at University of Texas Southwestern Medical Center in the US.

"We also identified a mechanism responsible for the differing response to the fasting treatment," he added.

Acute lymphoblastic leukemia, the most common type of leukemia found in children, can occur at any age. Acute myeloid leukemia (AML) is more common in adults.

The two types of leukemia arise from different bone marrow-derived blood cells, he explained. 

Acute lymphoblastic leukemia affects B cells and T cells, two types of the immune system's disease-fighting white blood cells. 

AML targets other types of white blood cells such as macrophages and granulocytes, among other cells.

In both ALL and AML, the cancerous cells remain immature yet proliferate uncontrollably.

Those cells fail to work well and displace healthy blood cells, leading to anemia and infection. They may also infiltrate into tissues and thus cause problems.

The researchers created several mouse models of acute leukemia and tried various dietary restriction plans. 

They used green or yellow florescent proteins to mark the cancer cells so they could trace them and determine if their levels rose or fell in response to the fasting treatment, Zhang explained.

"Strikingly, we found that in models of ALL, a regimen consisting of six cycles of one day of fasting followed by one day of feeding completely inhibited cancer development," he said. 

At the end of seven weeks, the fasted mice had virtually no detectible cancerous cells compared to an average of nearly 68 per cent of cells found to be cancerous in the test areas of the non-fasted mice, showed the findings published online in the journal Nature Medicine.

"Mice in the ALL model group that ate normally died within 59 days, while 75 percent of the fasted mice survived more than 120 days without signs of leukemia," Zhang said.

Fasting is known to reduce the level of leptin, a cell signalling molecule created by fat tissue. 

"We found that fasting decreased the levels of leptin circulating in the bloodstream as well as decreased the leptin levels in the bone marrow," he added.

Interestingly, acute myeloid leukemia was associated with higher levels of leptin receptors that were unaffected by fasting, which could help explain why the fasting treatment was ineffective against that form of leukemia.

New York, Dec 13 (IANS) Genes that are known to be essential to life -- the ones that human beings need to survive and thrive in the womb -- also play a critical role in the development of autism spectrum disorder (ASD) and lead to the disruption of normal social behaviour, suggests a new study.

ASD is a serious developmental disorder that impairs the ability to communicate and interact.

The findings suggest that ASD stems from an aggregate effect of many damaged essential genes that "work" together during the early stages of development in the womb, as soon as eight weeks after conception. 

ASD is a polygenic disease where many small gene effects contribute to a disorder, the researchers said.

"We know it's not one gene that's causing autism spectrum disorders; it's a background of mutations," said Maja Bucan, professor at the University of Pennsylvania in the US. 

For the study, the researchers analysed almost 4,000 essential genes and 5,000 non-essential genes in 2,013 males with ASD and 317 females with ASD, as well as their siblings who did not have ASD, for known exonic de novo (began in the child) and inherited mutations. 

They found that those with ASD had statistically significant elevated levels of mutations in essential genes compared to their siblings. 

The essential gene mutations were associated with a higher risk of ASD and disruption in normal social behaviour, the researchers noted.

On average, those with ASD had 44 per cent more early-in-childhood mutations and 1.3 per cent more inherited mutations in essential genes than their non-affected siblings.

In addition, the researchers identified a list of 29 "high-priority" essential genes that are co-expressed in the developing human brain with previously identified ASD-associated genes. 

"Focusing in on this group of genes will help shed more light on the complex genetic architecture of this disorder," explained Xiao Ji, a doctoral student at the University of Pennsylvania. 

The study was published online in the journal PNAS.