Spit-test can predict risk of depression in teens

London: Cambridge scientists have identified the first biomarker for clinical depression after they found that high levels of stress hormone in spit can indicate a serious risk of developing psychiatric disorders in teen boys.
 

Teenage boys with symptoms of depression and raised levels of the stress hormone cortisol are up to 14 times more likely to develop major depression than those without these traits, researchers found.
Clinical depression affects one in six people at some point in their lives. Until now, doctors have lacked a biomarker for clinical depression, partly because its causes and symptoms are so varied.
 

"Through our research, we now have a very real way of identifying those teenage boys most likely to develop clinical depression," said Professor Ian Goodyer of the University's Department of Psychiatry who led the study.
 

"This will help us strategically target preventions and interventions at these individuals and hopefully help reduce their risk of serious episodes of depression and their consequences in adult life," Goodyer said. The researchers collected spit samples from hundreds of teenagers and measured levels of cortisol in the saliva, as well as self-reported information on symptoms of depression.
 

This they used to divide the teenagers into one of four groups depending on their cortisol levels and symptoms of depression.
 

After following the group for 12 to 36 months, they were then able to work out which group was most likely to develop clinical depression and other psychiatric disorders. They found boys with high levels of cortisol and depressive symptoms were 14 times more likely to develop clinical depression than those with neither. In girls, however, this difference was less marked.
 

Girls with high cortisol and depressive symptoms were four times more likely to develop clinical depression than those with neither, suggesting gender differences in how depression develops.
 

The researchers hope that having an easily measurable biomarker - in this case, raised cortisol plus depressive symptoms - will allow primary care services to identify boys at high risk and consider new public mental health strategies for this part of the population.
 

"This new biomarker suggests that we may be able to offer a more personalised approach to tackling boys at risk for depression," said co-author Dr Matthew Owens.
 

The study was published in Proceedings of the National Academies of Science.

Scientists closer to find vaccine for dengue

Washington: Scientists have unveiled the mechanism behind how dengue enters cells of our immune system, a finding that could help develop vaccine for the deadly virus.

Dengue fever, an infectious tropical disease caused by a mosquito-borne virus, afflicts millions of people each year, causing fever, headache, muscle and joint pains and a characteristic skin rash, a PTI report quoting researchers, said.

In some people the disease progresses to a severe, often fatal, form known as dengue hemorrhagic fever. Despite its heavy toll, the prevention and clinical treatment of dengue infection has been a "dramatic failure in public health compared to other infectious diseases like HIV," said Ping Liu of the University of North Carolina at Chapel Hill.

Now, new research by Liu and her colleagues could offer vital insight into the mechanism of dengue virus entry into cells - and aid vaccine and clinical drug development.

Liu along with dengue fever expert Aravinda de Silva, used high-resolution microscopes to examine the expression of a particular protein, known as DC-SIGN, on the surface of immune system cells called dendritic cells.

The normal role of DC-SIGN (dendritic cell-specific intercellular adhesion molecule-grabbing nonintegrin) is to capture pathogens so that fragments of those pathogens can be presented as antigens on the surface of the dendritic cells.

Such antigens then are recognised by T cells - the workhorse cells of the immune system - "which is one of the first steps in the normal immune response," Liu said. While it has been known for some time that dengue used DC-SIGN to attach to cells, Liu and her colleagues used high-resolution microscopy to study exactly how the viruses used the protein to gain entry into cells.

"DC-SIGN has a unique carbohydrate recognition domain on its extracellular portion, which binds to all sorts of carbohydrates on pathogens," she said.

"An effective medication or vaccine should stop the process of dengue virus entry into cells," Liu said.
She said, de Silva and his colleagues have identified strong neutralisation antibodies that block dengue infection. By identifying the mechanism of antibody neutralisation, Liu and colleagues hope to advance the development of vaccines for dengue virus infections.

Scientists find safe way to kill cancer cells

Washington: Indian-origin scientists have successfully developed a radical new technique that may kill
brain tumours by hijacking them into toxic pits or areas of the body that are safer to operate on.

One factor that makes glioblastoma cancers so difficult to treat is that malignant cells from the tumours spread throughout the brain by following nerve fibres and blood vessels to invade new locations.     Now, researchers have learned to hijack this migratory mechanism, turning it against the cancer by using a film of nanofibres thinner than human hair to lure tumour cells away, a media report quoting PTI, said.

Instead of invading new areas, the migrating cells latch onto the specially-designed nanofibres and follow them to a location - potentially outside the brain - where they can be
captured and killed.

Using this technique, researchers can partially move tumours from inoperable locations to more accessible ones. Though it would not eliminate the cancer, the new technique reduced the size of brain tumours in animal models, suggesting that this form of brain cancer might one day be treated more like a chronic disease, researchers said.

"We have designed a polymer thin film nanofibre that mimics the structure of nerves and blood vessels that brain tumour cells normally use to invade other parts of the brain," said Ravi Bellamkonda, lead investigator and chair of the Wallace H Coulter Department of Biomedical Engineering at Georgia Tech and Emory University.

"The cancer cells normally latch onto these natural structures and ride them like a monorail to other parts of the brain. By providing an attractive alternative fibre, we can efficiently move the tumours along a different path to a destination that we choose," said Bellamkonda.

Treating the Glioblastoma multiforme cancer, also known as GBM, is difficult because the aggressive and invasive cancer often develops in parts of the brain where surgeons are
reluctant to operate.

Even if the primary tumour can be removed, however, it has often spread to other locations before being diagnosed. "The signalling pathways we were trying to activate to repair the spinal cord were the same pathways researchers would like to inactivate for glioblastomas," said first author
of the study, Anjana Jain, an assistant professor in the Department of Biomedical Engineering at Worcester Polytechnic Institute in Massachusetts.

Tumour cells typically invade healthy tissue by secreting enzymes that allow the invasion to take place, Jain said. That activity requires a significant amount of energy from the cancer cells.
"Our idea was to give the tumour cells a path of least resistance, one that resembles the natural structures in the brain, but is attractive because it does not require the cancer cells to expend any more energy," she said.

Details of the technique were reported in the journal Nature Materials.

Stay healthy with a glass of wine a day

Washington: Moderate alcohol consumption can boost your immune system and potentially improve your ability to fight infections, a new study has claimed.
 

A research team led by an immunologist at the University of California, Riverside found that moderate consumption of alcohol can improve immune response to vaccination.
 

The finding could pave the way for potentially new interventions to improve our ability to respond to vaccines and infections, benefiting vulnerable populations, such as the elderly for whom the flu vaccine, for example, has been found to be largely ineffective.
 

"It has been known for a long time that moderate alcohol consumption is associated with lower mortality," said Ilhem Messaoudi, an associate professor of biomedical sciences in the School of Medicine and lead author of the study published in the journal Vaccine.
 

"Our study, conducted on non-human  primates, shows for the first time that voluntary moderate alcohol consumption boosts immune responses to vaccination," Messaoudi said.
 

To study the impact of alcohol consumption on the immune system, the researchers trained 12 rhesus macaques to self-administer/consume alcohol on their own accord. The team first vaccinated the animals (against small pox) and then allowed them to access either 4 per cent ethanol (the experimental group) or calorically matched sugar water (the control group).
 

All the animals also had open access to water as an alternative fluid, as well as food. The researchers monitored the animals' daily ethanol consumption for 14 months. The animals were vaccinated one more time, seven months after the experiment began.
 

The research team found that over nine months of the animals' ethanol self-administration, mean daily ethanol intake varied markedly among them. "Like humans, rhesus macaques showed highly variable drinking behaviour. Some animals drank large volumes of ethanol, while others drank in moderation," Messaoudi said.
 

The animals' voluntary ethanol consumption segregated them into two groups: animals in the first group were those that consumed more alcohol, averaged a blood ethanol concentration (BEC) greater than the legal limit of 0.08 per cent and were therefore designated 'heavy drinkers'; animals in the second group consumed less alcohol, averaged a BEC of 0.02-0.04 per cent and were designated 'moderate drinkers.'
 

"Prior to consuming alcohol, all the animals showed comparable responses to vaccination. Following exposure to ethanol, however, the animals showed markedly different responses after receiving the booster vaccine," Messaoudi said. The researchers found that those animals that drank the
largest amounts of alcohol showed greatly diminished vaccine responses compared to the control group.

Soybean compound may prevent HIV spread

A compound found in soybeans can be used in new treatments to inhibit the deadly HIV infection, scientists claim. Researchers from George Mason University in the US found that genistein, derived from soybeans and other plants, may become an effective HIV treatment without the drug resistance issues faced by current therapies.

Genistein is a "tyrosine kinase inhibitor" that works by blocking the communication from a cell's surface sensors to its interior.

Found on a cell's surface, these sensors tell the cell about its environment and also communicate with other cells. HIV uses some of these surface sensors to trick the cell to send signals inside. These signals change cell structure so that the virus can get inside and spread infection.

But genistein blocks the signal and stops HIV from finding a way inside the cell. It takes a different approach than the standard antiretroviral drug used to inhibit HIV.

"Instead of directly acting on the virus, genistein interferes with the cellular processes that are necessary for the virus to infect cells," said Yuntao Wu, a professor with the George Mason-based National Center for Biodefense and Infectious Diseases and the Department of Molecular and Microbiology.

"Thus, it makes the virus more difficult to become resistant to the drug. Our study is currently in its early stage. If clinically proven effective, genistein may be used as a complement treatment for HIV infection," Wu said.
Researchers caution that this doesn't mean people should start eating large amounts of soy products.
"Although genistein is rich in several plants such as soybeans, it is still uncertain whether the amount of genistein we consume from eating soy is sufficient to inhibit HIV," Wu said.

Wu sees possibilities in this plant-based approach, which may address drug toxicity issues as well. Because genistein is plant-derived, it may be able to sidestep drug toxicity, a common byproduct of the daily and lifelong pharmaceutical regimen faced by patients with HIV to keep the disease at bay,
Wu said.

Typically, patients take a combination of multiple drugs to inhibit the virus. The frequency can lead to drug toxicity. Plus, HIV mutates and becomes drug-resistant. Wu and his team are working at finding out how much genistein is needed to inhibit HIV. It's possible that plants may not have high enough levels, so drugs would need to be developed, Wu said.

Urine may help regrow lost teeth

Stem cells obtained from urine could one day allow humans to regrow lost teeth, scientists claim. Chinese scientists used stem cells from urine to create tiny 'tooth buds' that when transplanted into mice grew into tooth-like structures.

Stem cells - cells which can grow into any type of tissue - are popular among researchers looking for ways to grow new teeth to replace those lost with age and poor dental hygiene.

The group at the Guangzhou Institutes of Biomedicine and Health used urine as the starting point, 'BBC News' reported. Cells which are normally passed from the body, such as those from the lining of the body's waterworks, are harvested in the laboratory. These collected cells are then coaxed into
becoming stem cells.
In the study, a mix of these cells and other material from a mouse was implanted into the animals. The researchers said that after three weeks the bundle of cells started to resemble a tooth: "The tooth-like structure contained dental pulp, dentin, enamel space and enamel organ."

However, the "teeth" were not as hard as natural teeth.  The research is not immediately going to lead to new options for the dentist, but researchers said it could lead to further studies towards "the final dream of total regeneration of human teeth for clinical therapy".

However, experts caution the goal faces many challenges. Professor Chris Mason, a stem cell scientist at University College London, said urine was a poor starting point. "It is probably one of the worst sources, there are very few cells in the first place and the efficiency of turning them into stem cells is very low. You just wouldn't do it in this way," he said.

He also warned that the risk of contamination, such as through bacteria, was much higher than with other sources of cells. The study was published in Cell Regeneration Journal.

Vitamin C proves new way to combat tuberculosis

In an "unexpected" discovery, vitamin C has been found to kill drug-resistant forms of tuberculosis, which could mean existing drugs can be redesigned to combat the disease.

Researchers at Albert Einstein College of Medicine of Yeshiva University, New York have determined that vitamin C kills drug-resistant tuberculosis (TB) bacteria in laboratory culture.

The finding suggests that vitamin C added to existing TB drugs could shorten TB therapy, and it highlights a new area for drug design. TB is caused by infection with the bacterium M tuberculosis. According to the World Health Organisation (WHO), TB sickened some 8.7 million people and took some 1.4 million lives in 2011, researchers said.

Infections that fail to respond to TB drugs are a growing problem: About 650,000 people worldwide now have multi-drug-resistant TB (MDR-TB), 9 per cent of whom have extensively drug-resistant TB (XDR-TB). The discovery arose during research into how TB bacteria become resistant to isoniazid, a potent first-line TB drug.

William Jacobs, lead investigator and senior author of the study and his colleagues observed that isoniazid-resistant TB bacteria were deficient in a molecule called mycothiol. "We hypothesised that TB bacteria that can't make mycothiol might contain more cysteine, an amino acid," said Jacobs.
 

"So, we predicted that if we added isoniazid and cysteine to isoniazid-sensitive M tuberculosis in culture, the bacteria would develop resistance. Instead, we ended up killing off the culture - something totally unexpected," he said.
 

Researchers suspected that cysteine was helping to kill TB bacteria by acting as a "reducing agent" that triggers the production of reactive oxygen species, which can damage DNA. "The combination of isoniazid and vitamin C sterilised the  M tuberculosis culture. We were then amazed to discover that vitamin C by itself not only sterilised the drug-susceptible TB, but also sterilised MDR-TB and XDR-TB strains," he said.

Vitamin C induced what is known as a Fenton reaction, causing iron to react with other molecules to create reactive oxygen species that kill the TB bacteria. "We don't know whether vitamin C will work in humans, but we now have a rational basis for doing a clinical trial," said Jacobs.