Knowledge Update

​London, Oct 2 (IANS) Excessive sugar consumption -- specifically the sugar fructose such as in soda -- has been linked to a rise in metabolic disease worldwide, a study has found.

Some investigators contend that commonly consumed amounts of sugar do not contribute to this epidemic. While others are convinced that excessive sugar ingestion is a major cause.

"There is still significant controversy as to whether sugar consumption is a major contributor to the development of diabetes," said senior author Mark Herman, Assistant Professor at Duke University.

However, "the study reveals a specific mechanism by which consuming fructose in large amounts, such as in soda, can cause problems", Herman added.

Insulin is a key hormone that regulates blood glucose after eating. Insulin resistance, when the body's metabolic tissues stop responding normally to insulin, is one of the earliest detectable changes in the progression to diabetes.

The likely cause of insulin resistance may not be the build-up of fat in the liver, as commonly believed, but may be caused by excess sugar in the liver that activates a molecular factor known as carbohydrate-responsive element-binding protein, or ChREBP.

ChREBP may then contribute to the development of both fatty liver and increased glucose production, the researchers said.

The ChREBP protein is found in several metabolic organs in mice, humans and other mammals.

"We found that no matter how much insulin the pancreas made, it couldn't override the processes started by this protein, ChREBP, to stimulate glucose production. This would ultimately cause blood sugar and insulin levels to increase, which over time can lead to insulin resistance elsewhere in the body," Herman explained.

To test their hypothesis, researchers studied mice that were genetically altered so their liver insulin signalling pathways were maximally activated -- in other words, their livers should not have been able to produce any glucose.

The researchers found that even in these mice, eating fructose triggered ChREBP-related processes in the liver, causing it to make more and more glucose, despite insulin signals telling it to stop.

Previous studies have reported that high fructose diets can cause multiple metabolic problems in humans and animals, including insulin resistance and fatty liver disease.

The finding could also help scientists one day diagnose metabolic disorders earlier on, potentially allowing patients to make changes to their diets and lifestyles sooner to prevent more serious complications.

The study published in the Journal of Clinical Investigation.

Sydney, Oct 2 (IANS) Researchers have found three-dimensional prints of a 400 million year old fish fossil that can reveal the possible evolutionary origins of human teeth.

The printed fish fossil was found around Lake Burrinjuck in southeast Australia, by researchers from The Australian National University (ANU) and Queensland Museum in Australia.

The team digitally dissected the jaws of a fossil Buchanosteus -- an armoured fish from the extinct placoderm group -- and used the 3-D prints to learn how the jaws moved and whether the fish had teeth.

"We are conducting further research on the internal tissue structure of tooth-like denticles in the mouth of the fish fossil, to determine whether they represent a transitional stage in the evolution of teeth," said Gavin Young, palaeontologist at The Australian National University (ANU).

In the study, the team used high-resolution CT scan to investigate the internal structure of very fragile fossil skulls and braincases that have been acid-etched from limestone rock.

"It's great that we are able to use recent technology, such as micro-CT scanning and 3-D printing, to examine some of the earliest known evidence of tooth-like structures in the most primitive jawed fishes," noted Carole Burrow from Queensland Museum.

The study helped determine when and how teeth -- a characteristic feature of all animal species with jaws, including humans -- had originated in evolutionary history.

The results were published in the journal Biology Letters.

​London, Oct 2 (IANS) Family history and environment of the residential area are responsible for the differences between individual immune systems, a study has found.

The study published in the journal Trends in Immunology, discusses what shapes our immune system and how it might be applied.

The study has shown that air quality, food, stress levels, sleep patterns, and lifestyle choices had a strong combined effect on immune responses.

"Diversity isn't just programmed into our genes -- it emerges from how our genes respond to the environment," said Adrian Liston, researcher at the Translational Immunology Laboratory, Belgium.

Long-term infections are responsible for most of the differences between individual immune systems. 

These interactions slowly change the cellular makeup of immune system and make it more sensitive to that specific virus but also easier for other infections to slip past its defences. 

"People without these infections don't experience these cellular changes and even with the occasional cold or fever, their immune systems stay relatively stable over time. The exception is when a person is elderly," Liston added.

Researchers have shown that ageing changes how our immune system responds to threats. 

According to the study, as one gets older an organ called the thymus gradually stops producing T cells, which are made to help to fight off infection. Without new T cells, older people are more likely to get sick and less likely to respond to vaccines.

Beyond T cells, ageing also seems to broadly change the way our immune systems react. 

"A lot of diseases that we associated with ageing have an inflammatory component, which suggests there is likely immune involvement," said Michelle Linterman, researcher at the Babraham Institute, Britain.

"Understanding how the immune system changes with age is going to be hugely important for treating age-related diseases in the future," Linterman added. 

Washington, Oct 1 (IANS) Homeopathic teething tablets and gels may pose a health risk to infants and children, the US Food and Drug Administration (FDA) has warned.

Consumers should stop using these products and dispose of any in their possession, FDA recommended on Friday. 

Homeopathic teething tablets and gels are distributed by CVS, Hyland's, and possibly others, and are sold in retail stores and online, the US drug regulator said in a statement.

Following the FDA's warning, CVS announced a voluntary withdrawal of all brands of homeopathic teething products sold in its retail stores and online at CVS.com.

"Consumers should seek medical care immediately if their child experiences seizures, difficulty breathing, lethargy, excessive sleepiness, muscle weakness, skin flushing, constipation, difficulty urinating, or agitation after using homeopathic teething tablets or gels," FDA said.

"Teething can be managed without prescription or over-the-counter remedies," said Janet Woodcock, Director of the FDA's Center for Drug Evaluation and Research. 

"We recommend parents and caregivers not give homeopathic teething tablets and gels to children and seek advice from their health care professional for safe alternatives," Woodcock noted.

The FDA is analysing adverse events reported to the agency regarding homeopathic teething tablets and gels, including seizures in infants and children who were given these products, since a 2010 safety alert about homeopathic teething tablets. 

The FDA is currently investigating this issue, including testing product samples.

​Toronto, Oct 1 (IANS) Researchers in Canada have developed two caffeine-based chemical compounds that show promise in preventing the ravages of Parkinson's disease.

Parkinson's disease attacks the nervous system, causing uncontrolled shakes, muscle stiffness, and slow, imprecise movement, chiefly in middle-aged and elderly people. 

It is caused by the loss of brain cells (neurons) that produce dopamine, an essential neurotransmitter that allows neurons to "talk" to each other.

The team from University of Saskatchewan focused on a protein called Alpha-synuclein (AS), which is involved in dopamine regulation.

In Parkinson's sufferers, AS gets misfolded into a compact structure associated with the death of dopamine-producing neurons. 

"Many of the current therapeutic compounds focus on boosting the dopamine output of surviving cells, but this is effective only as long as there are still enough cells to do the job," said one of the lead researchers Jeremy Lee from University of Saskatchewan College of Medicine.

"Our approach aims to protect dopamine-producing cells by preventing AS from mis-folding in the first place," Lee noted.

Although the chemistry was challenging, Lee explained the team synthesised 30 different "bifunctional dimer" drugs, that is, molecules that link two different substances known to have an effect on dopamine-producing cells. 

They started with a caffeine "scaffold," guided by literature that shows the stimulant has a protective effect against Parkinson's.

From this base, they added other compounds with known effects -- nicotine, the diabetes drug metformin, and aminoindan, a research chemical similar to the Parkinson's drug rasagiline.

Using a yeast model of Parkinson's disease, Lee and his team discovered two of the compounds prevented the AS protein from clumping, effectively allowing the cells to grow normally.

"Our results suggest these novel bifunctional dimers show promise in preventing the progression of Parkinson's disease," Lee said.

The findings were published in the journal ACS Chemical Neuroscience.

Singapore, Sep 30 (IANS) Oral administration of a compound derived from neem -- a medicinal plant native to the Indian sub-continent -- can significantly reduce the size of prostate tumour by up to 70 per cent as well as suppress its spread by half, a study led by an Indian-origin scientist has found.

Prostate cancer -- the most commonly diagnosed cancers worldwide -- occurs in a man's prostate -- a small walnut-shaped gland that produces seminal fluid. Current therapies available for metastatic prostate cancer are only marginally effective. 

The study revealed that nimbolide -- a bioactive terpenoid compound derived from neem plant -- can significantly suppress cell invasion and migration of prostate cancer cells, suggesting its ability to reduce tumour metastasis or spread.

"The study demonstrated that nimbolide can inhibit tumour cell viability -- a cellular process that directly affects the ability of a cell to proliferate, grow, divide, or repair damaged cell components -- and induce programmed cell death in prostate cancer cells," said Gautam Sethi, Associate Professor at the National University of Singapore (NUS). 

The findings showed that oral administration of nimbolide for 12 weeks can reduce the size of prostate cancer tumour by as much as 70 per cent and decreased its spread by about 50 per cent, without exhibiting any adverse effects.

Nimbolide directly targets glutathione reductase -- an enzyme which is responsible for maintaining the antioxidant system that regulates the STAT3 gene in the body. 

This activation of the STAT3 gene has been reported to contribute to prostate tumour growth and metastasis, explained the researchers. 

"We have found that nimbolide can substantially inhibit STAT3 activation and thereby abrogating the growth and metastasis of prostate tumour," Sethi added.

The results of the study were published in the journal Antioxidants & Redox Signaling.

​Washington, Sep 30 (IANS) Using data from NASA's Fermi Gamma-ray Space Telescope, scientists have found the first gamma-ray binary in another galaxy and the most luminous one ever seen.

The dual-star system, dubbed LMC P3, contains a massive star and a crushed stellar core that interact to produce a cyclic flood of gamma rays, the highest-energy form of light.

"Fermi has detected only five of these systems in our own galaxy, so finding one so luminous and distant is quite exciting," said lead researcher Robin Corbet from NASA's Goddard Space Flight Center in Greenbelt, Maryland.

Gamma-ray binaries are prized because the gamma-ray output changes significantly during each orbit and sometimes over longer time scales.

"This variation lets us study many of the emission processes common to other gamma-ray sources in unique detail," Corbet added.

These rare systems contain either a neutron star or a black hole and radiate most of their energy in the form of gamma rays.

LMC P3 is the most luminous such system known in gamma rays, X-rays, radio waves and visible light, and it's only the second one discovered with Fermi.

LMC P3 lies within the expanding debris of a supernova explosion located in the Large Magellanic Cloud (LMC), a small nearby galaxy about 163,000 light-years away.

In 2012, scientists using NASA's Chandra X-ray Observatory found a strong X-ray source within the supernova remnant and showed that it was orbiting a hot, young star many times the sun's mass.

Corbet's team discovered a 10.3-day cyclic change centred near one of several gamma-ray point sources recently identified in the LMC.

Prior to Fermi's launch, gamma-ray binaries were expected to be more numerous than they have turned out to be.

"It is certainly a surprise to detect a gamma-ray binary in another galaxy before we find more of them in our own," said Guillaume Dubus, a team member at the Institute of Planetology and Astrophysics of Grenoble in France.

A paper describing the discovery is forthcoming in The Astrophysical Journal.

New York, Sep 30 (IANS) Hypertension or high blood pressure is rapidly increasing in children, largely as a consequence of their obesity.

This high blood pressure in children and adolescents can significantly affect their mental skills, a study has found. 

In the study, children with hypertension performed low on cognitive tests on visual and verbal memory, processing speed, and verbal skills.

Children with sleep issues were found to have had hypertension, which intensified the effect of poor sleep on cognition and executive function, the researchers said. 

Knowing how these physical changes might affect cognitive skills could be important in future studies that assess whether anti-hypertensive treatments could improve cognitive performance in children with hypertension and reverse or prevent future adult hypertension-related problems, said Marc B. Lande from the University of Rochester in New York, US.

In the study, researchers compared different tests of cognitive skills in 75 children aged between 10-18 years with newly-diagnosed hypertension and 75 children without hypertension. 

The children with hypertension were not cognitively impaired, but rather performing less well than children without hypertension.

Overall, this study provides evidence that hypertension in children is associated with a subtle pattern of decreased performance on cognitive testing, the authors concluded. 

The study is forthcoming in The Journal of Pediatrics.

​New York, Oct 1 (IANS) Do we have an inherited hunting instinct, like dogs, cats and other predators? Quite likely, as the popularity of the augmented reality game Pokemon Go suggests, according to a new study.

Pokemon Go allows players to catch virtual wild animals in real-world locations through the mobile phone camera.

"It is possible that we all have the hunting instinct, but it has never been proven," said study author Vladimir Dinets, Assistant Research Professor of Psychology at University of Tennessee, Knoxville in the US.

"The recent explosive popularity of the Pokemon Go game, which allows players to hunt for virtual animals across a real terrain, shows how addictive such proxies can be and how many people can enjoy hunting-like behaviour despite being city dwellers completely isolated from natural environments," Dinets said. 

Hunting has played a major role in human history, helping humans survive and populate the world, but whether we have a an inherited hunting instinct or not is not known.

"The take-home message of the study is that we have predatory instincts and have to be aware of them. But this doesn't mean that we have to be real predators; instead, we can follow these instincts in more intelligent ways," Dinets added.

The study was published recently in the open-access journal Humanimalia.

New York, Sep 30 (IANS) Humans reached the southern cone of South America some 14,000 years ago, earlier than previously thought, says a study based on ancient artifacts found at an archaeological site in Argentina.

Humans' arrival in southern South America 14,000 years ago may represent the last step in the expansion of Homo sapiens throughout the world and the final continental colonisation, the researchers said.

Approximately 13,000 years ago, a prehistoric group of hunter-gathers known as the Clovis people lived in Northern America. 

Previous research suggests that the Clovis culture was one of the earliest cultures in South America. 

However, the new research from the Pampas region of Argentina supports the hypothesis that early Homo sapiens arrived in the South America earlier than the Clovis hunters did.

The evidence for earlier human arrival in South Americas comes from a rich archaeological site in southeastern South America called Arroyo Seco 2. 

"The Arroyo Seco 2 site contains a rich archaeological record, exceptional for South America, to explain the expansion of Homo sapiens into the Americas and their interaction with extinct Pleistocene mammals," the study said.

A group of scientists led by Gustavo Politis from Universidad Nacional del Centro de la Provincia de Buenos Aires presented the research in a new study published in the journal PLOS ONE.

At Arroyo Seco 2, the researchers excavated ancient tools, bone remains from a variety of extinct species, and broken animal bones containing fractures caused by human tools. 

They used radiocarbon dating to determine the age of the mammal bones and analyzed the specimens under a microscope.

The analysis revealed the presence of limb bones from extinct mammals at the site, which may indicate human activities of transporting and depositing animal carcasses for consumption at a temporary camp. 

The bones of some mammal species were concentrated in a specific part of the site, which could indicate designated areas for butchering activities. 

Microscopic examination also revealed that some bones contained fractures most likely caused by stone tools. 

The remains were dated between 14,064 and 13,068 years ago, and the authors believe that Arroyo Seco 2 may have been occupied by humans during that time.

This timeline, along with evidence from other South American sites, indicates that humans may have arrived in southern South America prior to the Clovis people inhabiting the Americas, but after the onset of the Last Glacial Maximum, the last glacial period, which took place 19,000 to 20,000 years ago, the researchers said.