Knowledge Update

London, May 10 (IANS) In a finding that could change the way the most common form of stroke is treated globally, researchers have shown that modified dosage of a clot-busting drug can reduce risk of serious bleeding in the brain and improve survival rates.

Intravenous rtPA (or alteplase) is given to people suffering acute ischaemic stroke and works by breaking up clots blocking the flow of blood to the brain.

However, it can cause serious bleeding in the brain in around five per cent of cases, with many of these proving fatal.

Compared to standard dose (0.9mg/kg body weight), the lower dose (0.6mg/kg) of rtPA reduced rates of serious bleeding in the brain, known as intracerebral haemorrhage (ICH), by two thirds, showed the results of the trial of more than 3,000 patients in 100 hospitals worldwide.

"Most patients who have a major stroke want to know they will survive but without being seriously dependent on their family. We have shown this to be the case with the lower dose of the drug,” said one of the researchers Tom Robinson, professor at University of Leicester in Britain.

The findings were published in the New England Journal of Medicine.

"At the moment you could have a stroke but end up dying from a bleed in the brain. It's largely unpredictable as to who will respond and who is at risk with rtPA,” lead author of the study Craig Anderson, professor at Sydney Medical School, University of Sydney in Australia.

"What we have shown is that if we reduce the dose level, we maintain most of the clot busting benefits of the higher dose but with significantly less major bleeds and improved survival rates. On a global scale, this approach could save the lives of many tens of thousands of people,” Anderson noted.​

​New York, May 6 (IANS) Although India managed to counter a steep decline in its vulture population in mid-1990s, these efficient scavengers are in danger of disappearing in many parts of the world primarily due to the presence of toxins in the carrion they consume.

Poisoning is the greatest extinction risk facing vultures, and impacts 88 percent of threatened vulture species, the study said.

Now, the center of the vulture crisis is in sub-Saharan Africa, the researchers noted.

In the mid-1990s India experienced a precipitous vulture decline, with more than 95 percent of vultures disappearing by the early 2000s. 

"That was a massive collapse that led a lot of people to really focus more attention on vultures," said one of the researchers Evan Buechley from University of Utah in the US.

The cause was eventually traced to diclofenac, a veterinary anti-inflammatory drug that relieved pain in cattle, but proved highly toxic to vultures. 

Hundreds of vultures would flock to each cattle carcass. And if the cow had recently been treated with diclofenac, hundreds of vultures would die. 

Because of this highly gregarious feeding behaviour, less than one percent of cattle carcasses contaminated with diclofenac could account for the steep vulture decline. 

Fortunately, international cooperation led to a total ban on veterinary diclofenac use. 

The numbers of vultures have stabilised, and are now showing signs of slowly increasing, Buechley said.

Losses of vultures can allow other scavengers to flourish, Buechley pointed out in a report published in the journa Biological Conservation.

For example, following the decline of vultures, India experienced a strong uptick in feral dogs --by an estimated seven million. 

The increase in dogs, potentially feeding on disease-ridden carcasses, is thought to have at least partially caused the rabies outbreak that was estimated to have killed 48,000 people from 1992-2006 in India -- deaths that may have been avoided if not for the disappearance of vultures.

Members of the Parsi sect of Zoroastrianism experienced a different impact. For thousands of years, the Parsi people have placed their dead on exposed mountaintops or tall towers for vultures to consume. The practice is called "sky burial."

But with few vultures and unable to properly handle their dead, the Parsis experienced a crisis within the faith. ​

Some constructed captive vulture aviaries. Others talked about desiccating bodies using focused solar mirrors. The Parsis' plight exemplifies the vultures' role in south Asian society -- and the various impacts if the vultures are not there.

Although the vulture crisis in Africa is ongoing, the researchers can predict what the outcome will be, based on previous experiences in India. 

Crows, gulls, rats and dogs will boom. And the rabies outbreak in India may just be a prologue, because several sub-Saharan Africa countries already have the highest per-capita rabies infection rates in the world, the researchers noted.

​New York, May 6 (IANS) Researchers have developed a miniature camera that can be mounted onto the eyeglasses of people who are legally blind -- vision with 20/200 or worse in the better eye -- and dramatically improve their ability to read an email or a newspaper article.

Made using optical character-recognition technology, the artificial vision device can be easily mounted onto the eyeglasses and works either by pointing at an item, tapping on it, or pressing a trigger button.



A wire attaches the device to a small pack containing its battery and computer. It recognises text and reads it to the user using an earpiece that transmits sound, and can also be programmed to recognise faces and commercial products.

The camera device offers hope to patients with age-related macular degeneration -- leading cause of permanent impairment of reading and fine or close-up vision in the elderly -- who are beyond medical or surgical therapy for the condition, researchers said.

“The device offers new hope for the large and growing number of individuals with age-related macular degeneration or advanced-stage glaucoma, two of the leading causes of vision loss among the elderly,” said one of the researchers Mark Mannis, professor at University of California in the US.

The device, which can be carried, fit into a pocket or attached to a belt, can also help older adults who are struggling with vision loss to better perform daily activities and could potentially bring greater independence, the researchers added in the paper published online in the journal JAMA Ophthalmology.

The team conducted a pilot study and analysed 12 participants with low vision, six men and six women, with an average age of 62. 

Using the device, the study participants were significantly better able to perform activities of daily living. 

"Our results show that it can be a very useful aid for patients with low vision in performing activities of daily living, and increase their functional independence," said another researcher Elad Moisseiev.​

​Washington, May 7 (IANS) Scientists have detected atomic oxygen in the Martian atmosphere for the first time since the last observation 40 years ago.

Atomic oxygen -- an elemental form of oxygen that does not exist in Earth's atmosphere -- affects how other gases escape Mars and therefore has a significant impact on the planet's atmosphere. 

An instrument onboard the Stratospheric Observatory for Infrared Astronomy (SOFIA) - a joint project of NASA and the German Aerospace Center - helped detect these atoms in the upper layers of the Martian atmosphere known as the mesosphere, NASA said in a statement.

"Atomic oxygen in the Martian atmosphere is notoriously difficult to measure," said SOFIA project scientist Pamela Marcum. 

"To observe the far-infrared wavelengths needed to detect atomic oxygen, researchers must be above the majority of Earth’s atmosphere and use highly sensitive instruments, in this case a spectrometer. SOFIA provides both capabilities," Marcum noted.

The scientists could detect only about half the amount of oxygen expected, which may be due to variations in the Martian atmosphere. 

The Viking and Mariner missions of the 1970s made the last measurements of atomic oxygen in the Martian atmosphere. 

These more recent observations were possible thanks to SOFIA’s airborne location, flying between 37,000-45,000 feet, above most of the infrared-blocking moisture in Earth’s atmosphere, NASA said.

The advanced detectors on one of the observatory’s instruments, the German Receiver for Astronomy at Terahertz Frequencies (GREAT), enabled astronomers to distinguish the oxygen in the Martian atmosphere from oxygen in Earth’s atmosphere.

The findings were presented in a paper published in the journal Astronomy and Astrophysics.

SOFIA is a Boeing 747SP jetliner modified to carry a 100-inch diametre telescope.​

​London, May 7 (IANS) Most people feel that friendship is a two-way street, but only half of your buddies would actually consider you their friend, a study has found, adding that this limits their ability to influence them and further impacts on human behaviour.

Companies and social groups that depend on social influence for collective action, information dissemination and product promotion could improve their strategies and interventions.

"It turns out that we're very bad at judging who our friends are and difficulty in determining the reciprocity of friendship significantly limits our ability to engage in cooperative arrangements," said Erez Shmueli from Tel Aviv University.

“We learned that we can't rely on our instincts or intuition. There must be an objective way to measure these relationships and quantify their impact," Shmueli added in a paper published in the journal PLoS One.

The team conducted extensive social experiments and examined six friendship surveys from some 600 students in Israel, Europe and the United States to assess friendship levels and expectations of reciprocity.

They then developed an algorithm that examines several objective features of a perceived friendship -- the number of common friends or the total number of friends and then distinguish between unidirectional and reciprocal.

The findings showed that 95 percent of participants think that their relationships were reciprocal.

"If you think someone is your friend, you expect him to feel the same way. But in fact that's not the case -- only 50 percent of those polled matched up in the bidirectional friendship category."

"Reciprocal relationships are important because of social influence as influence is the name of the game," Shmueli stated.​

New York, May 7 (IANS) Researchers have developed a new antibody-based drug that has the potential to slow down the replication of the human immunodeficiency virus (HIV) in the body and may also provide a better strategy for long-term control of the deadly infection.

Anti-retroviral therapy -- a combination of drugs that slows the replication of HIV in the body -- currently used to treat HIV has drawbacks. If a person discontinues his or her treatment, even missing a few doses, the level of the virus in the body is able to rebound quickly.

In the antibody therapy, the researchers used 3BNC117 -- a molecule -- also called as a broadly neutralising antibody because it has the ability to fight a wide range of HIV strains.

The findings of the first clinical trial showed that using the antibody could greatly reduce the amount of virus that is present in an individual's blood.

"This study provides evidence that a single dose of an antibody stimulates patients' immune response, enabling them to make new or better antibodies against the virus," said lead author Till Schoofs, postdoctoral fellow at The Rockefeller University in the US. 

For the study, published in the journal Science, the team included 15 patients, in the clinical trial, who had high levels of the virus in their blood, and 12 other patients whose virus levels were being controlled with antiretroviral therapy (ART). 

The patients were infused with a single dose of 3BNC117 and were monitored over a six-month period.

In 14 out of 15 patients who had higher levels of the virus at the time they were given the antibody were seen making new antibodies that could neutralise a number of different strains of HIV.

It usually takes several years for the body to begin to make good antibodies against HIV. So there might be an even better effect later on, especially if patients are given more than one dose of 3BNC117, the researchers added.

To determine further benefits of treatment with 3BNC117, the researchers conducted another study, also published in the journal Science, in a mouse model. 

The results revealed that 3BNC117 was able to engage the animals' immune cells and accelerate their clearance of HIV-infected cells. 

"This shows that the antibody not only can exert pressure on the virus, but also can shorten the survival of infected cells," first author of the study Ching-Lan Lu, doctoral student at The Rockefeller University, noted. 

Further, the researchers plan to test 3BNC117 in combination with other antibodies that target HIV, to determine whether an even stronger antiviral effect can be found. 

New York, May 8 (IANS) Climate change is likely to accelerate rates of chronic kidney disease worldwide as rising temperatures and heat stress harm kidneys.

New findings show that heat stress nephropathy -- chronic kidney diseases are on the rise, especially in many rural communities in hot regions.

With rise in temperature worldwide, dehydration and heat stress are likely to take a toll on the kidneys, emerging as a major cause of poor kidney health in the near future.

"A new type of kidney disease, occurring throughout the world in hot areas, is linked with temperature and climate and may be one of the first epidemics due to global warming," said Richard Johnson, from the University of Colorado in the US.

Also, global warming and a rise in extreme heat waves have increased the risk of kidney disease, especially for the agricultural workers, who are exposed to the heat for longer duration.

Decreasing amounts of rain contribute to the growing epidemic of the chronic kidney disease consistent with heat stress -- by reducing water supplies and quality as temperatures rise, the researchers noted.

"We were able to connect increased rates of chronic kidney disease in different areas to an underlying mechanism -- heat stress and dehydration -- and to climate," Johnson said.

The findings will be detailed in forthcoming issue of the Clinical Journal of the American Society of Nephrology (CJASN).

Governments and scientists need to work together to learn more about this threat and take action to reduce the risk of climate change-linked kidney disease, the researchers said.​

Washington, May 8 (IANS) NASA's MESSENGER mission has unveiled the first global digital elevation model (DEM) of Mercury, revealing in stunning detail the topography across the entire innermost planet.

It will also pave the way for scientists to fully characterise Mercury's geologic history.

"The wealth of these data has already enabled and will continue to enable exciting scientific discoveries about Mercury for decades to come," said Susan Ensor, software engineer at The Johns Hopkins University's Applied Physics Laboratory (APL).

This new model reveals a variety of interesting topographic features, including the highest and lowest points on the planet.

The highest elevation on Mercury is at 4.48 km above Mercury's average elevation, located just south of the equator in some of Mercury's oldest terrain.

The lowest elevation, at 5.38 km below Mercury's average, is found on the floor of Rachmaninoff basin, an intriguing double-ring impact basin suspected to host some of the most recent volcanic deposits on the planet.

More than 100,000 images were used to create the new model.

"This has become one of my favourite maps of Mercury. Now that it is available, I'm looking forward to it being used to investigate this epic volcanic event that shaped Mercury's surface," added Nancy Chabot, instrument scientist for the Mercury Dual Imaging System (MDIS) in a NASA statement.

"During its four years of orbital observations, MESSENGER revealed the global characteristics of one of our closest planetary neighbours for the first time.

The data from the mission will continue to be utilised by the planetary science community for years to come.​

New York, May 8 (IANS) Introducing a noise net around airfields that emit sound levels equivalent to those of a conversation in a busy restaurant could prevent collisions between birds and aircraft, saving lives and billions in damages, new research has found.

Filling a controlled area with acoustic noise around an airfield, where the majority of collisions tend to take place, can reduce the number of birds in the area by 80 percent, the findings showed.

"We are using a different kind of deterrent - trying to stop birds from hearing one another by playing a noise that is at the same pitch as the alarm calls or predator noises they are listening out for," said lead researcher John Swaddle, professor of biology at College of William and Mary in Williamsburg, US.

"By playing a noise at the same pitch, we mask those sounds, making the area much riskier for the birds to occupy. The birds don't like it and leave the area around the airfields, where there is potential for tremendous damage and loss of life," Swaddle noted.

The researchers set up speakers and amplifiers in three areas of an airfield in Virginia state and observed bird abundance over eight weeks, the first four weeks without noise and the second four weeks with the noise turned on.

Results showed a large decrease in the number of birds in the 'sonic net' and areas just outside and found that it was particularly effective at deterring a number of species that were at high risk of bird strike such as starlings.

"We have conducted prior research in an aviary but this is the first study done out in the field to show the efficacy of the sonic net," Swaddle, who is also a visiting research associate at University of Exeter in Britain, said.

The study was published in the journal Ecological Applications.

Bird strikes cost the aviation industry worldwide billions of dollars annually, and were responsible for 255 deaths between 1988 and 2013, yet measures to reduce these have been largely ineffective, the study noted.

Techniques to deter birds from airports include shooting, poisoning, live-capture and relocation, and the use of scare technologies, but these have proved largely ineffective.​

​New York, May 9 (IANS) Researchers have developed a device with the potential of shortening the time required to rapidly diagnose bacterial infections from days to a couple of hours.

The system could also allow point-of-care diagnosis, as it does not require the facilities and expertise available only in hospital laboratories, the study said. 

"Health-care-associated infections are a major problem that affects more than 600,000 patients each year, more than 10 percent of whom will die, and incurs more $100 billion in related costs," said co-senior author of the study Ralph Weissleder from Massachusetts General Hospital (MGH) in Boston, US.

"Rapid and efficient diagnosis of the pathogen is a critical first step in choosing the appropriate antibiotic regimen, and this system could provide that information in a physician's office in less than two hours," Weissleder noted.

The system developed by the MGH team, dubbed PAD for Polarization Anisotropy Diagnostics, allows for accurate genetic testing in a simple device. 

In this study, the team used a prototype PAD system to test clinical samples from nine patients and compared the results with those acquired by conventional microbiology cultures. 

Testing for the presence of five important bacterial species -- E. coli, Klebsiella, Acinetobacter, Pseudomonas, and Staph aureus -- and for factors indicating the virulence and antibiotic resistance of specific strains produced identical results with both procedures. 

But while PAD provided results in less than two hours, the bacterial culture process took three to five days. 

The findings were reported in the journal Science Advances.

"We can see three immediate applications for a system that can provide such rapid and accurate results - quickly diagnosing a patient's infection, determining whether antibiotic-resistant bacteria are present in a group of patients, and detecting bacterial contamination of medical devices or patient environments," co-senior author Hakho Lee, associate professor of radiology at Harvard Medical School, pointed out.​